External cephalic version: A terrible opportunity to waste (PDF ...

Journal of Perinatology (2009) 29, 77–78 r 2009 Nature Publishing Group All rights reserved. 0743-8346/09 $32 www.nature.com/jp

EDITORIAL

External cephalic version: a terrible opportunity to waste Journal of Perinatology (2009) 29, 77–78; doi:10.1038/jp.2008.232

Breech presentation complicates 3 to 4% of pregnancies at term. Since the Term Breech Trial was published,1 the rate of breech vaginal birth has fallen precipitously. Breech vaginal birth is no longer considered the standard of care and the vast majority of singleton breech presentations lead to a cesarean delivery. Meanwhile, the cesarean delivery rate in the United States has reached an all-time high of 31.1%2 and continues to increase annually. The primary cesarean delivery rate is similarly at an alltime high despite recommendations from Health People 2010 for a primary cesarean rate of 15%.3 Of these, an increasing number of primary cesarean deliveries are performed for breech presentation.4 The reasons fewer women today opt for attempted external cephalic version (ECV) are less clear. Patient request and physician ambivalence may be involved, driven by the concern that even if successful, ECV may result in a cesarean. In this issue, Clock et al. provide compelling evidence from a matched case–control study that women who have undergone a successful ECV are not at increased risk for cesarean delivery. The authors matched 197 women who had undergone successful ECV with the next 2 women of similar parity, gestational age, delivery history and type of labor who presented for labor management. They found successful ECV did not increase the chance of a cesarean or operative vaginal delivery. Even patients with a prior cesarean who underwent ECV had a similar cesarean rate when compared with the matched control group. The discrepancy in this finding from prior studies is not entirely clear. However, the authors did take great care to match appropriately study patients to controls with similar obstetric characteristics. Of great concern is the steady fall in ECV procedures seen during the study period, from 1998 to 2006. The reasons for this decline were not studied by the authors, but their postulates, that physician threshold for cesarean delivery is lower and patient request is more common, are plausible, and this topic deserves further study. Since the peak of vaginal birth after cesarean delivery in 1996, the rate of trial of labor after cesarean has steadily fallen as well and is currently less than 10%.2 Yet, complications from cesareans are well known. With each cesarean, a woman’s risk increases for abnormal placentation, hysterectomy, adhesion-related complications such as bowel, ureteral, and bladder injury, prolonged operative time, and for the sequelae of such complications including postoperative ventilation, hospital days, transfusion of more than four units of blood5 and maternal

mortality6. These risks are magnified when a woman undergoes multiple cesareans. Fetal and neonatal risks due to cesarean delivery are similarly significant. The risk of delivery-related perinatal death during a trial of labor is 11 times greater compared with a planned repeat cesarean delivery.7 Thus, prevention of the first cesarean is critical for reducing maternal and neonatal cesarean-related morbidities down the road. On the basis of data from their own institution, the authors estimate that if all eligible lower-risk women in the United States were offered ECV and just 46% accepted, 22 161 fewer cesarean deliveries would be performed each year. Although it may seem minor compared with more than 1 million cesareans per year, some among these women will incur future morbidities otherwise avoided by vaginal birth, such as trial-of-labor-related uterine rupture, difficult repeat cesarean delivery, adhesions, abnormal placentation, obstetric hemorrhage and pulmonary embolism, to name a few. However, while the authors’ estimates were appropriately conservative, imagine the overall reduction in cesareans that might be seen if ECV for breech presentation was considered the standard of care and if more than 60% of ECVs were successful. More than 50 000 unnecessary cesarean deliveries each year would reduce the overall cesarean delivery rate by more than 1%, reduce perinatal and maternal morbidity, and reduce healthcare costs in current and future pregnancies. If the trends of avoiding ECV and not performing trial of labor after cesarean continue, skills and comfort levels will continue to diminish, cesarean rates will continue to increase, morbidities from repeat cesarean will continue to increase and the door may eventually close on something that was once preventable. Although cesarean delivery has become safer throughout the twentieth century, its ease and availability should not be confused with being safer, on average, than vaginal delivery. Many cesareans can, and probably should, be reasonably avoided. This study lends support to the routine use of ECV, a safe procedure,8 as one component of an overall approach to reducing the cesarean rate. With trial of labor after cesarean rapidly disappearing, the opportunity to avoid a primary cesarean delivery is a terrible thing to waste.

1

DJ Lyell1 and AB Caughey2

Department of Obstetrics and Gynecology, Stanford University Medical Center, Stanford, CA, USA and 2Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, CA, USA E-mail: [email protected]

Editorial

78

References 1 Hannah ME, Hannah WJ, Hewson SA, Hodnett ED, Saigal S, Willan AR. Planned caesarean section versus planned vaginal birth for breech presentation at term: a randomised multicentre trial. Lancet 2000; 356: 1375–1383. 2 Hamilton BE, Martin JA, Ventura SJ. Births: Preliminary Data for 2006. National Vital Statistics Reports; vol 56 no 7. National Center for Health Statistics: Hyattsville, MD, 2007. 3 US Department of Health and Human Services. Health People 2010. 2nd Edn. Understanding and Improving Health and Objectives for Improving Health. 2 vols. Part 16 Maternal, Infant, and Child Health. US Government Printing Office: Washington, DC, 2000. 4 Rietberg C, Elfernik-Stinkens P, Visser G. The effect of the Term Breech Trial on medical intervention behaviour and neonatal outcome in the Netherlands: an analysis of 35 453 term breech infants. BJOG 2005; 112: 205–209.

Journal of Perinatology

5 Silver RM, Landon MB, Rouse DJ. Maternal morbidity associated with multiple repeat cesarean deliveries. Obstet Gynecol 2006; 107: 1226–1232. 6 Clark SL, Belfort MA, Dildy GA, Herbst MA, Meyers JA, Hankins GD. Maternal death in the 21st century: causes, prevention, and relationship to cesarean delivery. Am J Obstet Gynecol 2008; 199(1): 36.e1-5; discussion 91–2. e7–11. E-pub 2 May 2008. 7 Smith CS, Pell JP, Cameron AD, Dobbie R. Risk of perinatal death associated with labor after previous cesarean delivery in uncomplicated term pregnancies. JAMA 2002; 287: 2684–2690. 8 Grootscholten K, Kok M, Oei SG, Mol BWJ, van der Post JA. External cephalic version-related risks: a meta-analysis. Obstet Gynecol 2008; 112: 1143–1151.


STATE-OF-THE-ART

Potential of immunomodulatory agents for prevention and treatment of neonatal sepsis JL Wynn1, J Neu2, LL Moldawer3 and O Levy4 1

Division of Neonatology, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA; 2Department of Pediatrics, College of Medicine, University of Florida, Gainesville, FL, USA; 3Department of Surgery, College of Medicine, University of Florida, Gainesville, FL, USA and 4Division of Infectious Disease, Department of Medicine, Children’s Hospital Boston, Harvard Medical School, Boston, MA, USA

Prevention of neonatal infection-related mortality represents a significant global challenge particularly in the vulnerable premature population. The increased risk of death from sepsis is likely due to the specific immune deficits found in the neonate as compared to the adult. Stimulation of the neonatal immune system to prevent and/or treat infection has been attempted in the past largely without success. In this review, we identify some of the known deficits in the neonatal immune system and their clinical impact, summarize previous attempts at immunomodulation and the outcomes of these interventions, and discuss the potential of novel immunomodulatory therapies to improve neonatal sepsis outcome. Journal of Perinatology (2009) 29, 79–88; doi:10.1038/jp.2008.132; published online 4 September 2008

Keywords: immunomodulation; adjuvant; neonatal; sepsis; Toll-like receptor; innate immunity

Background and introduction Every year, more than one million newborns die from sepsis or serious infection in the first 4 weeks of life.1 Prevention of newborn infection therefore remains a significant global challenge. Neonatal healthcare providers routinely care for infants with risk factors, symptoms or signs of sepsis, requiring immediate clinical evaluation and presumptive antibiotic coverage. The need for such timely intervention is due to the high risk of mortality in this vulnerable population that is likely the result of multiple immunologic differences between the neonate and older populations. The teleology of these immunologic differences is believed to be focused on preventing preterm birth secondary to in utero inflammatory responses, reducing the likelihood of fetal rejection by the mother, and developing fetal immunologic tolerance.2 Although the quiescence of the fetal immune system is Correspondence: Dr James L. Wynn, Department of Pediatrics, Division of Neonatology, Duke University Medical Center, PO Box 3179, Durham, NC 27710, USA. E-mail: [email protected] Received 13 April 2008; revised 5 July 2008; accepted 19 July 2008; published online 4 September 2008

likely essential in utero, these responses ex utero may carry disadvantages, including impaired host defense against infection and weak neonatal vaccine responses that can impede efforts to protect this at risk population. Therefore, the newborn is relatively ill-equipped to deal with an infectious challenge and as a result exhibits increased morbidity and mortality compared to children and adults.3,4 These risks are significantly greater in premature, critically-ill neonates with exposure to intrapartum infections, premature rupture of membranes, or in which invasive procedures and mechanical ventilation are required.5 Although numerous studies have identified molecular markers of neonatal sepsis to facilitate early diagnosis, there has been relatively less study of the distinct pathophysiology of neonatal sepsis. Comprehensive investigation into the individual immunologic responses of neonatal sepsis may define functional immunodeficiencies that can be targeted to prevent or treat neonatal infection. Neonatal immune function Both innate and adaptive immunity are distinct at birth relative to adulthood.6 Neonatal immune responses are generally TH2-skewed, being geared towards immune tolerance instead of towards defense from microbial infections (TH1-skewed) (Table 1).7–10 Neonatal antigen-presenting cells (APCs) demonstrate impaired production of TH1-polarizing cytokines (for example, interleukin (IL)-12, interferon-g that direct immune responses against microbial pathogens) and impaired upregulation of costimulatory molecules to most Toll-like receptor (TLR) agonists.2,11,12 Nevertheless, certain stimuli such as Bacille Calmette-Guerin (BCG) induce adult-like responses by mechanisms that are not yet completely defined.7,13,14 In addition, neonatal T cells require increased stimulus to achieve adult-level responses.7,13,14 Compared to adults, neonates manifest delayed, shortened and decreased B-cell responses that limit their responses to infection and vaccination.7 Studies in adult mice using models of sepsis indicate that impairments in adaptive immunity result in poor survival,15–17 but the impact of the distinct neonatal adaptive immune system on neonatal sepsis survival has not been defined. Of note, adjuvants

Adjuvants in neonatal sepsis JL Wynn et al

80 Table 1 Deficits in neonatal adaptive immune function and the proposed clinical impact Adaptive immune deficit

Proposed clinical impact

Greater requirement for CD4 T-cell stimulation TH2-skewed and attenuated CD4 T-cell cytokine response Poor CD4 T-cell-dependent B-cell stimulation Decreased CD8 T-cell cytolytic activity Abundant, potent T regulatory cell population present at birth Maternal antibodies interfere with B-cell antibody response Weak humeral response, predominantly IgM Poor antibody response to polysaccharide antigens Deficient CD4 T-ligand stimulation of B cells Underdeveloped spleen and lymph nodes Limited antecedent exposure of T cells to foreign antigens

Decreased T-cell activities, proliferation Decreased response to infection, particularly intracellular pathogens Poor antibody production Decreased clearance of intracellularly infected cells Inhibited TH1 T-cell responses, decreased response to infection, limit vaccine responses of newborns Attenuated antibody production Poor opsonization and clearance of bacteria Increased susceptibility to encapsulated organisms Poor antibody production, lack of memory response Poor antibody production, poor clearance of bacteria from blood Lack of rapid, strong, memory response

Table 2 Deficits in neonatal innate immune function and the proposed clinical impact Innate immune deficit

Proposed clinical impact

Fragile, easily disrupted skin (particularly in premature) Decreased serum complement components

Portal of entry for microbes Decreased complement-mediated killing and opsonization lead to poor bacterial clearance and decreased naive B-cell activation Poor bacterial clearance

Defective neutrophil amplification, mobilization and function (phagocytosis, respiratory burst, lactoferrin and BPI production) Reduced MHC Class 2 expression on antigen presenting cells (APCs) Impaired APC function (decreased TH1-polarizing cytokine production, poor antigen presenting function, impaired mobilization, increased stimulation requirement to effect response) Depressed natural killer (NK) cell cytotoxic function Intrinsic immaturity of dendritic cells (DCs) Impaired cytokine production in response to pathogens Decreased neutrophil storage point in bone marrow Decreased opsonin production Impaired response to certain TLR agonists, decreased downstream signaling following TLR stimulation

Poor T- and B-cell stimulation Poor bacterial clearance

Poor clearance of cells infected with intracellular pathogens Poor antigen-presenting function, poor memory response Poor chemotactic gradient formation, poor cellular recruitment to site of inflammation Early depletion associated with poor sepsis outcomes Decreased uptake and killing by phagocytes Decreased chemotaxis and recruitment of innate cellular defenses

Abbreviations: BPI, bactericidal/permeability-increasing protein; TLR, Toll-like receptor.

directed at decreasing sepsis-induced adaptive immunodeficiencies (for example, inhibition of T- and B-cell apoptosis18 or enhancement of T-cell function19) improve sepsis outcomes in preclinical adult animal models. However, because the adaptive immune system does not function exactly in the neonate as it does in the adult,7 we must concede that therapies targeting adult sepsis-specific deficits may not work as effectively in neonates. The distinct function of the neonatal adaptive immune system renders the neonate especially dependent on the function of the innate immune system and on circulating maternal antibodies transferred during the last trimester, though these are deficient in the setting of prematurity. The neonatal innate immune system is also impaired compared to adults, likely contributing to their increased susceptibility to infection (Table 2).6,12,20 Neonates have fragile skin (preterm newborns), decreased circulating complement components (limiting opsonization/killing of pathogens), Journal of Perinatology

diminished expression of some antimicrobial proteins and peptides (APP), decreased production of type I interferons and TH1-polarizing cytokines (and a bias towards TH2-type responses), and quantitative and/or qualitative impairments in neutrophil, monocyte, macrophage and dendritic cell function.12 Neonatal leukocytes, particular under stress conditions, demonstrate diminished cellular functions necessary for bacterial clearance, including diminished responses to most TLR agonists (constituents of microbes), reduced production of cytokines/chemokines and APP, diapedesis, chemotaxis, phagocytosis and antigen presentation.6,12 Neonates are also deficient in functional splenic follicules that filter blood and remove pathogens, further limiting bacterial clearance, and increasing the risk of fulminant infection. The net effect of these deficits in neonatal immunity is to leave the neonate extremely susceptible to microbial invasion. There is therefore an unmet medical need to prevent and treat neonatal


81 Table 3 Attempts at neonatal immunomodulation and impact on sepsis survival Immunomodulation strategy

Proposed clinical benefit

Clinical impact

Granulocyte transfusion GM-CSF, G-CSF

Increase functional granulocytes (PMNs)

No change in sepsis mortality21

Stimulate proliferation and maturation of myeloid precursors in the bone marrow and modulate functions of mature PMNs at the site of infection Increase bacteria-specific serum antibody titers Bind to cell-surface receptors, provide opsonic activity, activate complement, promote antibody-dependent cytotoxicity

No change in sepsis mortality34– 38

IVIG (monoclonal) IVIG (polyclonal)

Probiotics

Breast milk Activated protein C Glutamine Pentoxifylline Antiendotoxin antibodies

Increase barrier to translocation of bacteria and bacterial products across mucosa, compatative exclusion of potential pathogens, modification of host response to microbial products Multiple mechanisms: contains cellular defenses, IgA, APP, probiotics, but growth factors Mechanism unclear Enhance gut integrity and immune function and decrease bacterial translocation Reduce TNF-a and IL-6 synthesis Decrease detrimental effects of endotoxin

No change in sepsis mortality or efficacy of sepsis prevention23,24,41,42 Small (3%) decrease in sepsis incidence, meta-analyses showed reduction in sepsis mortality with borderline statistical significance, INIS trial in progress25,28,38,41,43– 48 Limited data, reduction in NEC and NEC/sepsis mortality27

Clear proven reduction in neonatal infectious mortality28,58 –63 Limited data, no change in sepsis mortality, safety concerns28,48–50 No change in sepsis mortality30,53,56,57 Limited data, reduction in sepsis mortality31,32 Single small study, no change in mortality33

Abbreviations: APP, antimicrobial protein and peptide; GM-CSF, granulocyte-macrophage colony-stimulating factor; IgA, immunoglobulin A; IVIG, intravenous immmunogoblulin; IL-6, interleukin-6; NEC, necrotizing enterocolitis; TNF-a, tumor-necrosis factor alpha.

infection, and in this context, immunomodulatory agents are of considerable interest. Can the neonatal immune system be augmented in vivo to prevent and/or reduce sepsis mortality? Attempts at neonatal immunomodulation Experimentally and theoretically sound methods of immunomodulation directed at improving sepsis outcomes by correcting some neonatal immune deficits have been attempted without major improvement (Table 3).21–33 Therapies that enhance the quantity and/or quality of neutrophils, including granulocyte transfusions, granulocyte-macrophage colonystimulating factor (GM-CSF) and G-CSF have been studied in human neonates.34–38 These agents increase circulating numbers of neutrophils and appear to be safe, but have thus far been unsuccessful at significantly reducing neonatal sepsis mortality.21,22 The administration of intravenous immmunogoblulin (IVIG) (polyclonal and monoclonal) administration has been aimed at both prevention and treatment of bacterial infection in neonates39,40–48 but meta-analyses have demonstrated only a marginal clinical benefit in prevention and there is insufficient data at present to routinely recommend IVIG for treatment of neonatal sepsis.26 To more fully address the latter question of whether IVIG reduces sepsis (suspected or proven) mortality, a multicenter, international, double-blind, randomized controlled clinical trial (International

Neonatal Immunotherapy Study) has been completed with publication of the results anticipated in 2009. Other therapies such as activated protein C49 and pentoxfylline,31,32 (currently being evaluated in a phase II trial as an adjunctive treatment for necrotizing enterocolitis (NEC) in premature infants (ClinicalTrials.gov trial no. NCT00271336)) have shown some promise, although future evaluation is warranted as their mechanisms of action are incompletely characterized and dangerous side effects (increased risk of bleeding) remain a concern with activated protein C.50 Other potential immunomodulatory targets include reduction of oxidative stress and amino-acid supplementation during periods of critical illness. Melatonin, which reduced oxidative stress in neonatal animal models51 and free radical production in human neonates,52 was shown to reduce markers of inflammation and sepsis mortality in a very small study.52 Further investigation may be warranted in larger randomized controlled clinical trials to better assess the potential benefit of melatonin. When glutamine, an amino acid important for repair and growth of rapidly dividing tissues, was supplemented to critically ill adults, reduced rates of infection were noted.53–55 However, glutamine supplementation did not reduce nosocomial infections in preterm infants,30,56 or morbidity and mortality.57 As a ‘therapy’ with known immunologic benefit,6,58,59 human milk feeding has been associated with reduced infection in both term and preterm infants,6,60–63 and should be actively pursued. Journal of Perinatology


82

Role of probiotics in immunomodulation As the largest immune organ, the intestine serves as the major nexus of interaction with the external environment. The innate immune system of the intestine serves as a selective barrier to the postnatal presence of microbes and food antigens to prevent overwhelming systemic infection. At birth, the sterile intestine is rapidly colonized with microorganisms from maternal and environmental sources. Commensal microbes participate in health of the individual by being involved in nutrition and in gut development.64 Bacterial colonization of preterm infants differs from that of healthy full-term infants because of the methods of neonatal care (widespread prophylaxis with antibiotics, parenteral nutrition and feeding in incubators) that may delay or impair colonization. The effect of antibiotics on the developing gastrointestinal (GI) tract is incompletely understood, but recent studies in neonatal rodents demonstrate that the use of the ampicillin-like antibiotic, clomoxyl, alters development of intestinal gene expression.65 The short- and long-term effects of these antibiotic-driven alterations in the GI microbiota (>500 species of microbes are known to reside in the human GI tract,64,66) are the subject of intense research. The interaction between the mucosal immune system and the microbiota may be critical and the absence of this relationship may be involved in the development of autoimmune pathology and allergy. Probiotics have been successfully used as immunomodulators in the prevention and treatment of allergies in children,67,68 suggesting that modification of the relationship between the intestine and commensal organisms helps shape the immunologic network of the host and therefore could serve as a target for immunomodulation in premature neonates. Recent studies in mice demonstrating an increased susceptibility to hemorrhagic colitis after eradication of intestinal bacteria suggest that the epithelium and resident immune cells do not simply tolerate commensal organisms but are dependent on them for protection.69 Commensal bacteria express molecules such as lipopolysaccharide (LPS; Gram-negative bacteria), lipoteichoic acid (LTA; Gram-positive bacteria) and bacterial lipoproteins (BLPs, both Gram-negative and Gram-positive bacteria), that engage intestinal epithelial TLRs. The resultant tonic TLR signaling, enhances the ability of the epithelial surface to withstand chemical or inflammatory mediator-induced injury while also priming the surface for enhanced repair responses69,70 (Figure 1). This is due in part to selective coupling of TLR pathways in intestinal epithelial cells to production of antiinflammatory and repair-enhancing cytokines.71 The importance of TLR expression and stimulation in the development of NEC was highlighted in a recent report in neonatal mice indicating that overexpression of TLR4, following hypoxia or remote infection, was associated with a decreased ability of the intestine to withstand damage as well as an impairment in intestinal repair mechanisms.72,73 Thus, either the disruption of Journal of Perinatology

gut TLR signaling or the removal of TLR agonists compromises the ability of the intestinal surface to protect and repair itself in the face of an inflammatory or infectious insult,69,70,74 increasing the risk of bacterial translocation and the development of endotoxemia, sepsis and/or NEC. Preterm human infants randomly assigned to receive a daily feeding supplement of a probiotic mixture compared to nonprobiotic administered control infants had a relative risk reduction in mortality, incidence of NEC and late onset sepsis.27,75 However, a large multicenter trial conducted in 12 Italian neonatal intensive care units on 565 patients did not elicit a statistically significant beneficial effect of probiotic (Lactobacillus GG) on NEC or sepsis.76 In a recent meta-analysis, probiotic treatment was shown to reduce the incidence of higher Bell stage NEC (stage 2 and higher) and mortality in preterm infants less than 1500 g.77 Whether the differences in outcomes in these studies are associated with the use of different probiotic preparations, a different baseline incidence of NEC and sepsis in the different neonatal intensive care units, or other factors such as breast milk feeding remain speculative. Previous studies suggest that human breast milk contains beneficial microbes that are independent of those found in the areolar skin.78 The role of human milk, itself replete with innate immune effectors including APP and TLR modulators,79,80 versus formula feedings in the probiotic studies mentioned above was not critically examined but is clearly worthy of future study. Additional studies are also necessary to clarify whether types of probiotics (live or inactivated bacteria or their corresponding TLR agonists) and their dosage have a differential impact on NEC prevention and/or sepsis survival, as well as on long-term outcome measures including safety. Where do we go from here? In vitro studies light the wayy Many in vitro studies of neonatal leukocytes have identified functional deficiencies, pointing to potential future immunomodulatory therapies that may enhance specific facets of neonatal immune function, such as cytokine and APP production as well as phagocytosis. To facilitate the translation of this in vitro data to the bedside, preclinical models in animals have been employed. For example, studies of sepsis in adult animals have guided biopharmaceutical development of novel sepsis therapies including probiotics,81 caspase inhibitors,18 glucocorticoid-induced tumornecrosis factor (TNF)-a receptor stimulation,19 TLR modulation,82–84 as well as glucocorticoids, antiendotoxin antibodies, IL-1 receptor antagonists, anti-TNF-a antibodies, recombinant bactericidal/ permeability-increasing protein (BPI),85 and others.86 However, much of the descriptive and mechanistic work characterizing the immune response in sepsis has been carried out using adult animal models that may not necessarily apply to neonates given the distinct function of the neonatal immune system.12


83

Figure 1 Interaction of microbiota and neonatal intestine. The interaction between intestinal bacteria and intestinal epithelium is necessary for homeostasis and normal function of repair mechanisms. Disruption of this interaction, through the use of antibiotics or via stress to the organism (i.e., remote infection or hypoxia), results in loss of homeostasis and degradation of the intestinal boundaries with subsequent microbial translocation *such as pneumonia or sepsis.

Innate immune system enhancement by TLR stimulation Following the description of TLRs in humans,87 the characterization of their respective effects has grown exponentially. Widely expressed by invertebrate and vertebrate animals, TLRs detect pathogen-associated molecular patterns, triggering host cell cytokine and antimicrobial effector responses,88,89 (Figure 2). TLRtriggered responses are differentially regulated at the genetic level and constitute an adaptive component of the innate immune system. For example, upon restimulation of leukocytes with TLR agonists, potentially harmful excessive inflammatory cytokine production is reduced whereas antimicrobial genes remain active.90 The contribution of TLR activation, signaling and expression to human disease is currently an area of intensive study across many medical disciplines.91 In the context of well-described in vitro deficits in neonatal immunity, the TLRs prominent role in innate immunity sparked studies to assess whether TLR activation improves neonatal cellular responses.92–98 Major differences exist between newborns and

adults in TLR-mediated monocyte activation, but these differences are not uniform across all TLRs.99 Although neonatal APCs demonstrate impaired production of TH1-polarizing cytokines (for example, TNF-a and IL-12) and impaired upregulation of costimulatory molecules in responses to agonists of TLRs 1 to 7, responses to TLR8 agonists are remarkably preserved.99–101 Impaired TLR signaling also contributes to reduced neonatal leukocyte responses to bacterial cell wall products, potentially contributing to neonatal risk of infection.97 Impairment in the ability of human neonatal blood monocytes to produce TNF-a in response to TLR agonists is due to the inhibitory effects of plasma adenosine, which binds its specific adenosine receptor thereby increasing intracellular concentrations of the second messenger cyclic adenosine monophosphate (cAMP).102,103 Neonatal blood plasma contains relatively high concentrations of adenosine and neonatal cord blood mononuclear cells demonstrate increased sensitivity to the cAMP-mediated inhibitory effects of adenosine.104 cAMP inhibits production of Journal of Perinatology


84

Figure 2 Toll-like receptors (TLRs) and their respective agonists. Schematic representation of TLRs, both cell surface and endocytic, as well as their respective ligands. Stimulation of these receptors causes enhanced immune function through increased cellular cytokine production and improvement of antimicrobial effector mechanisms such as cellular phagocytosis and antimicrobial protein and peptide (APP) production. LTA, lipotechoic acid; PG, peptidoglycan; LPS, lipopolysaccharide.

multiple TH1-polarizing cytokines while preserving production of counter-regulatory cytokines such as IL-10. Thus, the adenosine system is important in limiting TLR2-mediated blood monocyte production of TNF-a and other TH1-polarizing cytokines, during exposure of the neonate to microbial flora during the birth process.12 TLR8 agonists, including single-stranded RNAs and synthetic imidazoquinoline compounds, represent an important exception to the general pattern of impaired human neonatal monocyte responses to TLR agonists.101,105 Recent in vivo studies have explored whether priming of an innate immune response by pretreatment of neonatal mice with TLR agonists improves outcomes of infection. Priming using TLR9 agonist (CpG) was protective against Listeria monocytogenes or neurotropic Tacaribe arenavirus (a powerfully lethal murine-specific virus) in single-pathogen challenge murine neonatal sepsis models.106,107 Using a neonatal murine model of polymicrobial sepsis,108 we showed that a single small dose before sepsis with TLR7/8 agonist (the imidazoquinoline resiquimod), or TLR4 agonist (LPS), was able to reduce polymicrobial sepsis mortality by 25 and 40%, respectively, over sham-treated septic animals.109 Importantly, we found TLR agonist Journal of Perinatology

priming was not uniformly beneficial, as TLR3 agonist pretreated mice had no advantage over sham-treated septic animals. TLR7/8 and TLR4 agonist pretreatment enhanced but shortened the systemic inflammatory response seen with sepsis, decreased bacteremia and improved survival, but were associated with distinct enhancement of innate immune function including increased polymorphonuclear cell (PMN) recruitment, and reactive oxygen species production (TLR4) or phagocytic function (TLR7/8) (Figure 3). In contrast to results in adult mice, in which the absence of the adaptive immune system was associated with significantly higher mortality (B60% higher than wild type), there was no difference in neonatal sepsis mortality when compared to the wild-type mice, emphasizing the dependence of the neonate on innate immunity for sepsis survival. Lastly, we showed that the survival benefit conferred by pretreatment with TLR agonists were also evident in neonatal mice lacking an adaptive immune system, confirming that the benefits of TLR agonist pretreatment are through stimulation of innate immunity alone. Thus, in marked contrast to adults, in whom absence or dysfunction of the adaptive immune system negatively affects survival following polymicrobial sepsis, neonates demonstrate a dependence on innate immune


85

Figure 3 Effect of Toll-like receptor (TLR) agonist pretreatment on sepsis survival, cytokine production, bacteremia and innate cellular function in neonatal mice. Systemic administration of select TLR agonists before the initiation of experimental polymicrobial sepsis significantly reduces murine neonatal mortality and is associated with a more robust but shortened inflammatory response and unique improvements in cell function (increased phagocytosis and reactive oxygen species production) with associated decreases in bacteremia as compared to saline-pretreated neonatal mice.

function that is improved through select TLR stimulation resulting in increased sepsis survival with minimal or no contribution of the adaptive immune system. Potential for prophylactic immunomodulation Efforts aimed at improving neonatal sepsis survival by using adjuvants must take into consideration the unique aspects of neonatal immunity and sepsis to develop age-appropriate therapies. Specific TLR stimulation appears to effectively address some of the known deficits unique to neonatal immunity, including the longappreciated impairment in phagocytic function during stress conditions.12,110,111 The efficacy of TLR agonist pretreatment in improving survival in preclinical models of severe infection is thus of great interest. Such a prophylactic approach is particularly appropriate for low-birth weight extremely premature neonates, a group at high risk for infection112 due to particularly impaired innate immune responses (for example, skin immaturity, particularly low complement and APP levels, and deficiency of passive immunoglobulins) as well as exposure to multiple invasive procedures, including intubation, central venous line placement,

delayed feeding and monitoring devices. Premature infants suffer the highest sepsis mortality of any population and early onset lethal sepsis (during the first week of life) is predominantly due to Gram-negative bacteria.112 If a prophylactic protective immune response could be generated that would persist through this crucial time, it is likely that the mortality within this population could be dramatically reduced. As a result, potential prophylactic approaches directed at priming the neonatal immune system before a potential insult are of substantial interest. Priming innate immunity might also serve other immunocompromised medical populations such as those who have received chemotherapy or those who are pharmacologically immunosuppressed. Potential adverse effects of immunomodulation Immunomodulation is not without theoretical risk of unwanted side effects. Improvements in innate cellular function might come at the expense of increased autoimmunity or other inflammatory damage. Because neonates with antenatal conditions which produce excessive inflammation (such as chorioamnionitis) are known to have Journal of Perinatology


86

associated pathology such as periventricular leukomalacia or chronic lung disease,113 the notion of augmenting the immune system response must be tempered by concerns for potential untoward effects. The recent discovery that effects of TLR stimulation, including cytokine production and antimicrobial effector mechanisms, are differentially regulated suggests that selective immunomodulatory effects can be elicited through specific pharmacologic targeting.90 TLR agonists, such as BCG (a TLR2 and four agonist114), are already given to neonates at birth to reduce tuberculosis. More studies examining the effects of TLR stimulation in vivo are necessary in neonatal animal models, including nonhuman primates, whose TLR pathways more closely conform to those of humans,115 with emphasis on determination of pharmacokinetics, pharmacodynamics and potential side effects.

14

15

16

17

18

19

Summary Modulation of innate immune responses provides fresh opportunities for improving sepsis survival in neonates. Targeting high-risk populations for selective immunoprophylaxis to enhance host defense against bacterial infection is a promising approach whose realization will require further progress regarding mechanisms of action, pharmacologic properties and safety.

20 21

22 23

References 1 Lawn JE, Cousens S, Zupan J. 4 million neonatal deaths: when? Where? Why? Lancet 2005; 365(9462): 891–900. 2 Marodi L. Innate cellular immune responses in newborns. Clin Immunol 2006; 118(2–3): 137–144. 3 Martin GS, Mannino DM, Eaton S, Moss M. The epidemiology of sepsis in the United States from 1979 through 2000. N Engl J Med 2003; 348(16): 1546–1554. 4 Barton P, Kalil AC, Nadel S, Goldstein B, Okhuysen-Cawley R, Brilli RJ et al. Safety, pharmacokinetics, and pharmacodynamics of drotrecogin alfa (activated) in children with severe sepsis. Pediatrics 2004; 113(1 Part 1): 7–17. 5 Martinot A, Leclerc F, Cremer R, Leteurtre S, Fourier C, Hue V. Sepsis in neonates and children: definitions, epidemiology, and outcome. Pediatr Emerg Care 1997; 13(4): 277–281. 6 Lawrence RM, Pane CA. Human breast milk: current concepts of immunology and infectious diseases. Curr Probl Pediatr Adolesc Health Care 2007; 37(1): 7–36. 7 Adkins B, Leclerc C, Marshall-Clarke S. Neonatal adaptive immunity comes of age. Nat Rev Immunol 2004; 4(7): 553–564. 8 Siegrist CA. The challenges of vaccine responses in early life: selected examples. J Comp Pathol 2007; 137(Suppl 1): S4–S9. 9 Hanekom WA. The immune response to BCG vaccination of newborns. Ann N Y Acad Sci 2005; 1062: 69–78. 10 Marchant A, Goldman M. T cell-mediated immune responses in human newborns: ready to learn? Clin Exp Immunol 2005; 141(1): 10–18. 11 Byun HJ, Jung WW, Lee JB, Chung HY, Sul D, Kim SJ et al. An evaluation of the neonatal immune system using a listeria infection model. Neonatology 2007; 92(2): 83–90. 12 Levy O. Innate immunity of the newborn: basic mechanisms and clinical correlates. Nat Rev Immunol 2007; 7(5): 379–390. 13 Nonnecke BJ, Waters WR, Foote MR, Palmer MV, Miller BL, Johnson TE et al. Development of an adult-like cell-mediated immune response in calves after early


24

25

26 27

28

29

30

31 32

33

vaccination with Mycobacterium bovis bacillus Calmette-Guerin. J Dairy Sci 2005; 88(1): 195–210. Marchant A, Appay V, Van Der Sande M, Dulphy N, Liesnard C, Kidd M et al. Mature CD8(+) T lymphocyte response to viral infection during fetal life. J Clin Invest 2003; 111(11): 1747–1755. Scumpia PO, McAuliffe PF, O’Malley KA, Ungaro R, Uchida T, Matsumoto T et al. CD11c+ dendritic cells are required for survival in murine polymicrobial sepsis. J Immunol 2005; 175(5): 3282–3286. Hotchkiss RS, Tinsley KW, Swanson PE, Grayson MH, Osborne DF, Wagner TH et al. Depletion of dendritic cells, but not macrophages, in patients with sepsis. J Immunol 2002; 168(5): 2493–2500. Hotchkiss RS, Tinsley KW, Swanson PE, Schmieg Jr RE, Hui JJ, Chang KC et al. Sepsis-induced apoptosis causes progressive profound depletion of B and CD4+ T lymphocytes in humans. J Immunol 2001; 166(11): 6952–6963. Hotchkiss RS, Chang KC, Swanson PE, Tinsley KW, Hui JJ, Klender P et al. Caspase inhibitors improve survival in sepsis: a critical role of the lymphocyte. Nat Immunol 2000; 1(6): 496–501. Scumpia PO, Delano MJ, Kelly-Scumpia KM, Weinstein JS, Wynn JL, Winfield RD et al. Treatment with GITR agonistic antibody corrects adaptive immune dysfunction in sepsis. Blood 2007; 110(10): 3673–3681. Petrova A, Mehta R. Dysfunction of innate immunity and associated pathology in neonates. Indian J Pediatr 2007; 74(2): 185–191. Mohan P, Brocklehurst P. Granulocyte transfusions for neonates with confirmed or suspected sepsis and neutropaenia. Cochrane Database Syst Rev 2003; (4): CD003956. Carr R, Modi N, Dore C. G-CSF and GM-CSF for treating or preventing neonatal infections. Cochrane Database Syst Rev 2003; (3): CD003066. DeJonge M, Burchfield D, Bloom B, Duenas M, Walker W, Polak M et al. Clinical trial of safety and efficacy of INH-A21 for the prevention of nosocomial staphylococcal bloodstream infection in premature infants. J Pediatr 2007; 151(3): 260–265, 5 e1. Benjamin Jr DK, Schelonka R, White R, Holley Jr HP, Bifano E, Cummings J et al. A blinded, randomized, multicenter study of an intravenous Staphylococcus aureus immune globulin. J Perinatol 2006; 26(5): 290. Ohlsson A, Lacy JB. Intravenous immunoglobulin for preventing infection in preterm and/or low-birth-weight infants. Cochrane Database Syst Rev 2004; (1): CD000361. Ohlsson A, Lacy JB. Intravenous immunoglobulin for suspected or subsequently proven infection in neonates. Cochrane Database Syst Rev 2004; (1): CD001239. Lin HC, Su BH, Chen AC, Lin TW, Tsai CH, Yeh TF et al. Oral probiotics reduce the incidence and severity of necrotizing enterocolitis in very low birth weight infants. Pediatrics 2005; 115(1): 1–4. el-Mohandes AE, Picard MB, Simmens SJ, Keiser JF. Use of human milk in the intensive care nursery decreases the incidence of nosocomial sepsis. J Perinatol 1997; 17(2): 130–134. Goldstein B, Nadel S, Peters M, Barton R, Machado F, Levy H et al. ENHANCE: results of a global open-label trial of drotrecogin alfa (activated) in children with severe sepsis. Pediatr Crit Care Med 2006; 7(3): 200–211. Poindexter BB, Ehrenkranz RA, Stoll BJ, Wright LL, Poole WK, Oh W et al. Parenteral glutamine supplementation does not reduce the risk of mortality or late-onset sepsis in extremely low birth weight infants. Pediatrics 2004; 113(5): 1209–1215. Haque K, Mohan P. Pentoxifylline for neonatal sepsis. Cochrane Database Syst Rev 2003; (4): CD004205. Lauterbach R, Pawlik D, Kowalczyk D, Ksycinski W, Helwich E, Zembala M. Effect of the immunomodulating agent, pentoxifylline, in the treatment of sepsis in prematurely delivered infants: a placebo-controlled, double-blind trial. Crit Care Med 1999; 27(4): 807–814. Adhikari M, Coovadia HM, Gaffin SL, Brock-Utne JG, Marivate M, Pudifin DJ. Septicaemic low birthweight neonates treated with human antibodies to endotoxin. Arch Dis Child 1985; 60(4): 382–384.


87 34 Ahmad A, Laborada G, Bussel J, Nesin M. Comparison of recombinant granulocyte colony-stimulating factor, recombinant human granulocyte-macrophage colonystimulating factor and placebo for treatment of septic preterm infants. Pediatr Infect Dis J 2002; 21(11): 1061–1065. 35 Bilgin K, Yaramis A, Haspolat K, Tas MA, Gunbey S, Derman O. A randomized trial of granulocyte-macrophage colony-stimulating factor in neonates with sepsis and neutropenia. Pediatrics 2001; 107(1): 36–41. 36 Carr R, Modi N, Dore CJ, El-Rifai R, Lindo D. A randomized, controlled trial of prophylactic granulocyte-macrophage colony-stimulating factor in human newborns less than 32 weeks gestation. Pediatrics 1999; 103(4 Part 1): 796–802. 37 Kucukoduk S, Sezer T, Yildiran A, Albayrak D. Randomized, double-blinded, placebocontrolled trial of early administration of recombinant human granulocyte colonystimulating factor to non-neutropenic preterm newborns between 33 and 36 weeks with presumed sepsis. Scand J Infect Dis 2002; 34(12): 893–897. 38 Miura E, Procianoy RS, Bittar C, Miura CS, Miura MS, Mello C et al. A randomized, double-masked, placebo-controlled trial of recombinant granulocyte colonystimulating factor administration to preterm infants with the clinical diagnosis of early-onset sepsis. Pediatrics 2001; 107(1): 30–35. 39 Sandberg K, Fasth A, Berger A, Eibl M, Isacson K, Lischka A et al. Preterm infants with low immunoglobulin G levels have increased risk of neonatal sepsis but do not benefit from prophylactic immunoglobulin G. J Pediatr 2000; 137(5): 623–628. 40 Bloom B, Schelonka R, Kueser T, Walker W, Jung E, Kaufman D et al. Multicenter study to assess safety and efficacy of INH-A21, a donor-selected human staphylococcal immunoglobulin, for prevention of nosocomial infections in very low birth weight infants. Pediatr Infect Dis J 2005; 24(10): 858–866. 41 Shenoi A, Nagesh NK, Maiya PP, Bhat SR, Subba Rao SD. Multicenter randomized placebo controlled trial of therapy with intravenous immunoglobulin in decreasing mortality due to neonatal sepsis. Indian Pediatr 1999; 36(11): 1113–1118. 42 Lassiter HA, Robinson TW, Brown MS, Hall DC, Hill HR, Christensen RD. Effect of intravenous immunoglobulin G on the deposition of immunoglobulin G and C3 onto type III group B streptococcus and Escherichia coli K1. J Perinatol 1996; 16(5): 346–351. 43 Atici A, Satar M, Karabay A, Yilmaz M. Intravenous immunoglobulin for prophylaxis of nosocomial sepsis. Indian J Pediatr 1996; 63(4): 517–521. 44 Haque KN, Remo C, Bahakim H. Comparison of two types of intravenous immunoglobulins in the treatment of neonatal sepsis. Clin Exp Immunol 1995; 101(2): 328–333. 45 Weisman LE, Stoll BJ, Kueser TJ, Rubio TT, Frank CG, Heiman HS et al. Intravenous immune globulin prophylaxis of late-onset sepsis in premature neonates. J Pediatr 1994; 125(6 Part 1): 922–930. 46 Weisman LE, Stoll BJ, Kueser TJ, Rubio TT, Frank CG, Heiman HS et al. Intravenous immune globulin therapy for early-onset sepsis in premature neonates. J Pediatr 1992; 121(3): 434–443. 47 Clapp DW, Kliegman RM, Baley JE, Shenker N, Kyllonen K, Fanaroff AA et al. Use of intravenously administered immune globulin to prevent nosocomial sepsis in low birth weight infants: report of a pilot study. J Pediatr 1989; 115(6): 973–978. 48 Haque KN, Zaidi MH, Haque SK, Bahakim H, el-Hazmi M, el-Swailam M. Intravenous immunoglobulin for prevention of sepsis in preterm and low birth weight infants. Pediatr Infect Dis 1986; 5(6): 622–625. 49 Kylat RI, Ohlsson A. Recombinant human activated protein C for severe sepsis in neonates. Cochrane Database Syst Rev 2006; (2): CD005385. 50 Nadel S, Goldstein B, Williams MD, Dalton H, Peters M, Macias WL et al. Drotrecogin alfa (activated) in children with severe sepsis: a multicentre phase III randomised controlled trial. Lancet 2007; 369(9564): 836–843. 51 Ozdemir D, Uysal N, Tugyan K, Gonenc S, Acikgoz O, Aksu I et al. The effect of melatonin on endotoxemia-induced intestinal apoptosis and oxidative stress in infant rats. Intensive Care Med 2007; 33(3): 511–516. 52 Gitto E, Karbownik M, Reiter RJ, Tan DX, Cuzzocrea S, Chiurazzi P et al. Effects of melatonin treatment in septic newborns. Pediatr Res 2001; 50(6): 756–760.

53 Novak F, Heyland DK, Avenell A, Drover JW, Su X. Glutamine supplementation in serious illness: a systematic review of the evidence. Crit Care Med 2002; 30(9): 2022–2029. 54 Murray SM, Pindoria S. Nutrition support for bone marrow transplant patients. Cochrane Database Syst Rev 2002; (2): CD002920. 55 Houdijk AP, Rijnsburger ER, Jansen J, Wesdorp RI, Weiss JK, McCamish MA et al. Randomised trial of glutamine-enriched enteral nutrition on infectious morbidity in patients with multiple trauma. Lancet 1998; 352(9130): 772–776. 56 Vaughn P, Thomas P, Clark R, Neu J. Enteral glutamine supplementation and morbidity in low birth weight infants. J Pediatr 2003; 142(6): 662–668. 57 Tubman TR, Thompson SW, McGuire W. Glutamine supplementation to prevent morbidity and mortality in preterm infants. Cochrane Database Syst Rev 2008; (1): CD001457. 58 Hanson LA, Korotkova M. The role of breastfeeding in prevention of neonatal infection. Semin Neonatol 2002; 7(4): 275–281. 59 Newburg DS, Walker WA. Protection of the neonate by the innate immune system of developing gut and of human milk. Pediatr Res 2007; 61(1): 2–8. 60 Dewey KG, Heinig MJ, Nommsen-Rivers LA. Differences in morbidity between breastfed and formula-fed infants. J Pediatr 1995; 126(5 Part 1): 696–702. 61 Howie PW, Forsyth JS, Ogston SA, Clark A, Florey CD. Protective effect of breast feeding against infection. BMJ 1990; 300(6716): 11–16. 62 Hylander MA, Strobino DM, Dhanireddy R. Human milk feedings and infection among very low birth weight infants. Pediatrics 1998; 102(3): E38. 63 Schanler RJ, Shulman RJ, Lau C. Feeding strategies for premature infants: beneficial outcomes of feeding fortified human milk versus preterm formula. Pediatrics 1999; 103(6 Part 1): 1150–1157. 64 Hooper LV. Bacterial contributions to mammalian gut development. Trends Microbiol 2004; 12(3): 129–134. 65 Schumann A, Nutten S, Donnicola D, Comelli EM, Mansourian R, Cherbut C et al. Neonatal antibiotic treatment alters gastrointestinal tract developmental gene expression and intestinal barrier transcriptome. Physiol Genomics 2005; 23(2): 235–245. 66 Hooper LV, Gordon JI. Commensal host–bacterial relationships in the gut. Science 2001; 292(5519): 1115–1118. 67 Pohjavuori E, Viljanen M, Korpela R, Kuitunen M, Tiittanen M, Vaarala O et al. Lactobacillus GG effect in increasing IFN-gamma production in infants with cow0 s milk allergy. J Allergy Clin Immunol 2004; 114(1): 131–136. 68 Marschan E, Kuitunen M, Kukkonen K, Poussa T, Sarnesto A, Haahtela T et al. Probiotics in infancy induce protective immune profiles that are characteristic for chronic low-grade inflammation. Clin Exp Allergy 2008; 38(4): 611–618. 69 Rakoff-Nahoum S, Paglino J, Eslami-Varzaneh F, Edberg S, Medzhitov R. Recognition of commensal microflora by toll-like receptors is required for intestinal homeostasis. Cell 2004; 118(2): 229–241. 70 Savidge TC, Newman PG, Pan WH, Weng MQ, Shi HN, McCormick BA et al. Lipopolysaccharide-induced human enterocyte tolerance to cytokine-mediated interleukin-8 production may occur independently of TLR-4/MD-2 signaling. Pediatr Res 2006; 59(1): 89–95. 71 Martin CR, Walker WA. Intestinal immune defences and the inflammatory response in necrotising enterocolitis. Semin Fetal Neonatal Med 2006; 11(5): 369–377. 72 Jilling T, Simon D, Lu J, Meng FJ, Li D, Schy R et al. The roles of bacteria and TLR4 in rat and murine models of necrotizing enterocolitis. J Immunol 2006; 177(5): 3273–3282. 73 Gribar SC, Anand RJ, Sodhi CP, Hackam DJ. The role of epithelial Toll-like receptor signaling in the pathogenesis of intestinal inflammation. J Leukoc Biol 2008; 83(3): 493–498. 74 Madara J. Building an intestineFarchitectural contributions of commensal bacteria. N Engl J Med 2004; 351(16): 1685–1686. 75 Bin-Nun A, Bromiker R, Wilschanski M, Kaplan M, Rudensky B, Caplan M et al. Oral probiotics prevent necrotizing enterocolitis in very low birth weight neonates. J Pediatr 2005; 147(2): 192–196.



88 76 Dani C, Biadaioli R, Bertini G, Martelli E, Rubaltelli FF. Probiotics feeding in prevention of urinary tract infection, bacterial sepsis and necrotizing enterocolitis in preterm infants. A prospective double-blind study. Biol Neonate 2002; 82(2): 103–108. 77 Alfaleh K, Bassler D. Probiotics for prevention of necrotizing enterocolitis in preterm infants. Cochrane Database Syst Rev 2008; (1): CD005496. 78 Martin R, Heilig HG, Zoetendal EG, Jimenez E, Fernandez L, Smidt H et al. Cultivation-independent assessment of the bacterial diversity of breast milk among healthy women. Res Microbiol 2007; 158(1): 31–37. 79 Phadke SM, Deslouches B, Hileman SE, Montelaro RC, Wiesenfeld HC, Mietzner TA. Antimicrobial peptides in mucosal secretions: the importance of local secretions in mitigating infection. J Nutr 2005; 135(5): 1289–1293. 80 LeBouder E, Rey-Nores JE, Raby AC, Affolter M, Vidal K, Thornton CA et al. Modulation of neonatal microbial recognition: TLR-mediated innate immune responses are specifically and differentially modulated by human milk. J Immunol 2006; 176(6): 3742–3752. 81 Tok D, Ilkgul O, Bengmark S, Aydede H, Erhan Y, Taneli F et al. Pretreatment with pro- and synbiotics reduces peritonitis-induced acute lung injury in rats. J Trauma 2007; 62(4): 880–885. 82 Weighardt H, Feterowski C, Veit M, Rump M, Wagner H, Holzmann B. Increased resistance against acute polymicrobial sepsis in mice challenged with immunostimulatory CpG oligodeoxynucleotides is related to an enhanced innate effector cell response. J Immunol 2000; 165(8): 4537–4543. 83 Feterowski C, Weighardt H, Emmanuilidis K, Hartung T, Holzmann B. Immune protection against septic peritonitis in endotoxin-primed mice is related to reduced neutrophil apoptosis. Eur J Immunol 2001; 31(4): 1268–1277. 84 Feterowski C, Novotny A, Kaiser-Moore S, Muhlradt PF, Rossmann-Bloeck T, Rump M et al. Attenuated pathogenesis of polymicrobial peritonitis in mice after TLR2 agonist pre-treatment involves ST2 up-regulation. Int Immunol 2005; 17(8): 1035–1046. 85 Levin M, Quint PA, Goldstein B, Barton P, Bradley JS, Shemie SD et al. Recombinant bactericidal/permeability-increasing protein (rBPI21) as adjunctive treatment for children with severe meningococcal sepsis: a randomised trial. rBPI21 Meningococcal Sepsis Study Group. Lancet 2000; 356(9234): 961–967. 86 Marshall JC. Such stuff as dreams are made on: mediator-directed therapy in sepsis. Nat Rev Drug Discov 2003; 2(5): 391–405. 87 Medzhitov R, Preston-Hurlburt P, Janeway Jr CA. A human homologue of the Drosophila Toll protein signals activation of adaptive immunity. Nature 1997; 388(6640): 394–397. 88 Kawai T, Akira S. TLR signaling. Semin Immunol 2007; 19(1): 24–32. 89 Doyle SE, O0 Connell RM, Miranda GA, Vaidya SA, Chow EK, Liu PT et al. Toll-like receptors induce a phagocytic gene program through p38. J Exp Med 2004; 199(1): 81–90. 90 Foster SL, Hargreaves DC, Medzhitov R. Gene-specific control of inflammation by TLR-induced chromatin modifications. Nature 2007; 447(7147): 972–978. 91 Kanzler H, Barrat FJ, Hessel EM, Coffman RL. Therapeutic targeting of innate immunity with Toll-like receptor agonists and antagonists. Nat Med 2007; 13(5): 552–559. 92 De Wit D, Tonon S, Olislagers V, Goriely S, Boutriaux M, Goldman M et al. Impaired responses to toll-like receptor 4 and toll-like receptor 3 ligands in human cord blood. J Autoimmun 2003; 21(3): 277–281. 93 Yan SR, Qing G, Byers DM, Stadnyk AW, Al-Hertani W, Bortolussi R. Role of MyD88 in diminished tumor necrosis factor alpha production by newborn mononuclear cells in response to lipopolysaccharide. Infect Immun 2004; 72(3): 1223–1229. 94 Schaub B, Bellou A, Gibbons FK, Velasco G, Campo M, He H et al. TLR2 and TLR4 stimulation differentially induce cytokine secretion in human neonatal, adult, and murine mononuclear cells. J Interferon Cytokine Res 2004; 24(9): 543–552. 95 Aksoy E, Albarani V, Nguyen M, Laes JF, Ruelle JL, De Wit D et al. Interferon regulatory factor 3-dependent responses to lipopolysaccharide are selectively blunted in cord blood cells. Blood 2007; 109(7): 2887–2893.


96 Sadeghi K, Berger A, Langgartner M, Prusa AR, Hayde M, Herkner K et al. Immaturity of infection control in preterm and term newborns is associated with impaired tolllike receptor signaling. J Infect Dis 2007; 195(2): 296–302. 97 Al-Hertani W, Yan SR, Byers DM, Bortolussi R. Human newborn polymorphonuclear neutrophils exhibit decreased levels of MyD88 and attenuated p38 phosphorylation in response to lipopolysaccharide. Clin Invest Med 2007; 30(2): E44–E53. 98 Krumbiegel D, Zepp F, Meyer CU. Combined Toll-like receptor agonists synergistically increase production of inflammatory cytokines in human neonatal dendritic cells. Hum Immunol 2007; 68(10): 813–822. 99 Levy O, Zarember KA, Roy RM, Cywes C, Godowski PJ, Wessels MR. Selective impairment of TLR-mediated innate immunity in human newborns: neonatal blood plasma reduces monocyte TNF-alpha induction by bacterial lipopeptides, lipopolysaccharide, and imiquimod, but preserves the response to R-848. J Immunol 2004; 173(7): 4627–4634. 100 Levy O. Innate immunity of the human newborn: distinct cytokine responses to LPS and other Toll-like receptor agonists. J Endotoxin Res 2005; 11(2): 113–116. 101 Levy O, Suter EE, Miller RL, Wessels MR. Unique efficacy of Toll-like receptor 8 agonists in activating human neonatal antigen-presenting cells. Blood 2006; 108(4): 1284–1290. 102 Hasko G, Cronstein BN. Adenosine: an endogenous regulator of innate immunity. Trends Immunol 2004; 25(1): 33–39. 103 Sitkovsky M, Lukashev D. Regulation of immune cells by local-tissue oxygen tension: HIF1 alpha and adenosine receptors. Nat Rev Immunol 2005; 5(9): 712–721. 104 Levy O, Coughlin M, Cronstein BN, Roy RM, Desai A, Wessels MR. The adenosine system selectively inhibits TLR-mediated TNF-alpha production in the human newborn. J Immunol 2006; 177(3): 1956–1966. 105 Philbin VJ, Levy O. Immunostimulatory activity of Toll-like receptor 8 agonists towards human leucocytes: basic mechanisms and translational opportunities. Biochem Soc Trans 2007; 35(Part 6): 1485–1491. 106 Ito S, Ishii KJ, Gursel M, Shirotra H, Ihata A, Klinman DM. CpG oligodeoxynucleotides enhance neonatal resistance to Listeria infection. J Immunol 2005; 174(2): 777–782. 107 Pedras-Vasconcelos JA, Goucher D, Puig M, Tonelli LH, Wang V, Ito S et al. CpG oligodeoxynucleotides protect newborn mice from a lethal challenge with the neurotropic Tacaribe arenavirus. J Immunol 2006; 176(8): 4940–4949. 108 Wynn JL, Scumpia PO, Delano MJ, O0 Malley KA, Ungaro R, Abouhamze A et al. Increased mortality and altered immunity in neonatal sepsis produced by generalized peritonitis. Shock 2007; 28(6): 675–683. 109 Wynn JL, Scumpia PO, Winfield RD, Delano MJ, Kelly-Scumpia K, Barker T et al. Defective innate immunity predisposes murine neonates to poor sepsis outcome, but is reversed by TLR agonists. Blood 2008 Jun 30. [Epub ahead of print]. 110 Henneke P, Berner R. Interaction of neonatal phagocytes with group B streptococcus: recognition and response. Infect Immun 2006; 74(6): 3085–3095. 111 Carr R. Neutrophil production and function in newborn infants. Br J Haematol 2000; 110(1): 18–28. 112 Stoll BJ, Hansen NI, Higgins RD, Fanaroff AA, Duara S, Goldberg R et al. Very low birth weight preterm infants with early onset neonatal sepsis: the predominance of Gram-negative infections continues in the National Institute of Child Health and Human Development Neonatal Research Network, 2002 to 2003. Pediatr Infect Dis J 2005; 24(7): 635–639. 113 Gotsch F, Romero R, Kusanovic JP, Mazaki-Tovi S, Pineles BL, Erez O et al. The fetal inflammatory response syndrome. Clin Obstet Gynecol 2007; 50(3): 652–683. 114 Tsuji S, Matsumoto M, Takeuchi O, Akira S, Azuma I, Hayashi A et al. Maturation of human dendritic cells by cell wall skeleton of Mycobacterium bovis bacillus CalmetteGuerin: involvement of toll-like receptors. Infect Immun 2000; 68(12): 6883–6890. 115 Sanghavi SK, Shankarappa R, Reinhart TA. Genetic analysis of Toll/Interleukin-1 Receptor (TIR) domain sequences from rhesus macaque Toll-like receptors (TLRs) 1 to 10 reveals high homology to human TLR/TIR sequences. Immunogenetics 2004; 56(9): 667–674.


ORIGINAL ARTICLE

Cesarean risk after successful external cephalic version: a matched, retrospective analysis C Clock1, J Kurtzman2,3, J White3 and JH Chung3 1

Department of Obstetrics and Gynecology, Oregon Health Sciences University, Portland, OR, USA; 2Department of Obstetrics and Gynecology, Saddleback Memorial Medical Center, Laguna Hills, CA, USA and 3Department of Obstetrics and Gynecology, Irvine Medical Center, University of California, Orange, CA, USA Objective: To determine the odds of cesarean, operative vaginal delivery and vaginal birth after cesarean after successful external cephalic version (ECV) compared with singleton pregnancies eligible for a trial of labor.

Study Design: A matched case–control study was performed using the Memorial Care OBStat Database from 1 January 1998 to 31 July 2006. We identified 197 participants who underwent a successful ECV (study group) and compared them with the next two women presenting for labor management, matched for parity, gestational age, delivery history (previous cesarean delivery) and type of labor (spontaneous or induced). Result: There was no significant difference in the adjusted matched odds of cesarean delivery between the study group and control group overall (16.8 vs 11.9%; odds ratio (OR) 1.70; 95% confidence interval (CI) 0.98 to 2.97), even when subanalyzed according to parity. There was also no significant difference in adjusted matched odds of operative vaginal delivery for the study group and control group, 15.9 vs 8.9% (OR 1.06; 95% CI 0.32 to 3.51). Among patients with a prior cesarean, those who underwent successful ECV had a cesarean delivery rate of 11.1% compared with 16.7% in the matched control group (OR 0.59; 95% CI 0.47 to 7.43). Conclusion: Cesarean delivery and operative vaginal delivery rates following successful ECV are not increased in our data set compared with matched controls, even in patients with a prior cesarean delivery. This information may be useful when counseling patients who are contemplating an ECV attempt due to non-cephalic presentation at term. Journal of Perinatology (2009) 29, 96–100; doi:10.1038/jp.2008.227; published online 8 January 2009 Keywords: external cephalic version; cesarean delivery; breech presentation

Introduction Breech presentation complicates 3 to 4% of term pregnancies, and planned vaginal delivery for a singleton, term, breech presentation Correspondence: Dr C Clock, Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Oregon Health Sciences University, 3181 SW Sam Jackson Park Rd, Mail Code L548, Portland, OR 97239, USA. E-mail: [email protected] Received 1 June 2008; revised 21 November 2008; accepted 23 November 2008; published online 8 January 2009

has been associated with a higher neonatal morbidity than elective cesarean delivery. 1,2 In an attempt to minimize the risks associated with either breech vaginal delivery or elective cesarean delivery, the American College of Obstetricians and Gynecologists recommended application of external cephalic version (ECV) to reduce breech presentations in singleton gestations.3 ECV is a safe and effective method that consists of rotating the fetus from breech to cephalic presentation by external manipulation of the mother’s abdomen, with the success rate ranging from 44 to 77%.2,4 Although the intent of ECV is to decrease the overall cesarean delivery rate for breech presentation, there is controversy as to whether this is ultimately achieved. Some studies have shown an increased rate of cesarean delivery following successful ECV, whereas others have not.5–12 Part of the difficulty in drawing a conclusion from these studies is that differing control groups and matching characteristics have been used. In addition, small sample sizes may have been a limiting factor in some studies. Further, many have excluded participants with prior cesarean delivery, making information on this subset of individuals limited. Therefore, the goals of this investigation were to settle the questions as to whether successful ECV truly lowers the rate of cesarean delivery in patients with non-cephalic presentation and whether women undergoing successful ECV have a higher rate of cesarean delivery as compared with those presenting for labor management at term with spontaneous cephalic presentations.

Methods This is a matched case–control study that was performed at Saddleback Memorial Medical Center, an academically affiliated, community-based hospital. Before study initiation, institutional review board approval for human participant research was obtained from the Memorial Services Office of Research Administration. Cases were identified in a retrospective fashion using a contemporaneously collected, quality assurance perinatal database known as OBStat. Cases were defined as participants with a singleton gestation who underwent a successful ECV for malpresentation during the study period from 1 January 1998 to 31

Cesarean risk after successful cephalic version C Clock et al

97

July 2006. The obstetric and perinatal information of this study population was retrieved from the Memorial Care OBStat Database. The information in this database is entered by a trained clinical nurse and is checked weekly for accuracy. During the study period, the clinical protocol of the department was to offer ECV to women with a breech presentation at 36 weeks’ gestation or beyond. ECV was not offered or performed if the patient had any of the following contraindications: multifetal pregnancy, placenta previa, third trimester bleeding, oligohydramnios (amniotic fluid index 36 weeks’ gestation. ECV was attempted on 420 (46.0%) participants, of which 197 were successful (47.5%). We identified 394 matched controls for a total sample of 591 participants. Though delivery volume remained relatively steady in our medical center during the study period (approximately 250 per month), the average number of ECV attempts during the study period peaked at 3 per month in 2002 and had been decreasing since that time till it reached less than 1 per month. There were no significant differences between the two groups with respect to maternal age or medical complications including insulin-dependent diabetes, cardiac disease, gestational diabetes mellitus, chronic hypertension or pre-eclampsia (Table 1). Other demographic factors that may potentially impact the cesarean delivery rate, such as ethnicity and epidural use, were not statistically significantly different between the groups. In contrast, participants who underwent successful ECV had a higher proportion of deliveries at 41 weeks’ gestation or later, though not significant. Among those participants requiring induction of labor, the mean interval from ECV to induction was 13.6 days (range 0 to 38 days). As induction status was one of the matching criteria, there was no difference between the two groups (Table 1). Twenty patients (10.2%) underwent induction of labor within 24 h following successful ECV. Within this group, indications for induction included elective (15%), abnormal post-procedure nonstress tests (10%), post-dates (10%), suspected macrosomia (5%) and pre-eclampsia (5%). The remaining indications for induction were unspecified. Of the women undergoing successful ECV, 83.2% were subsequently delivered vaginally. Despite a slightly higher overall rate of cesarean delivery in the ECV group vs controls (16.8 vs 11.9%), the matched odds ratio (OR) for the primary outcome of cesarean delivery was not statistically different between the two groups, based on a 95% CI that crosses one (OR 1.70; 95% CI 0.98 to 2.97). There was also no statistical difference in the indication for cesarean delivery between the ECV cases and controls (data not shown). When the population was subdivided based on parity, the cesarean rate was higher among nulliparous women, but the matched odds of cesarean delivery showed no statistical difference between the ECV group and controls (Table 2). Journal of Perinatology

Cesarean risk after successful cephalic version C Clock et al

98 Table 1 Demographic data by ECV status Unadjusted matched OR (95% CI)a

ECV No (N ¼ 394)

Yes (N ¼ 197)

Maternal age X35 years