Early Endotoxemia Increases Peripheral and ... - Semantic Scholar

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Early Endotoxemia Increases Peripheral and Hepatic Insulin Sensitivity in Healthy Humans Saskia N. van der Crabben, Regje M. E. Blu¨mer, Michiel E. Stegenga, Marie¨tte T. Ackermans, Erik Endert, Michael W. T. Tanck, Mireille J. Serlie, Tom van der Poll, and Hans P. Sauerwein Department of Endocrinology and Metabolism (S.N.v.d.C., R.M.E.B., M.J.S., H.P.S.), Center for Experimental and Molecular Medicine (M.E.S., T.v.d.P.), Department of Clinical Chemistry, Laboratory of Endocrinology and Radiochemistry (M.T.A., E.E.), and Department of Clinical Epidemiology, Biostatistics, and Bioinformatics (M.W.T.T.), Academic Medical Center, 1100 DD Amsterdam, The Netherlands

Context: Sepsis-induced hypoglycemia is a well known, but rare, event of unknown origin. Objective: The aim of the study was to obtain insight into the mechanism of sepsis-induced hypoglycemia, focusing on glucose kinetics and insulin sensitivity measured with stable isotopes by using the model of human endotoxemia. Design: Glucose metabolism was measured during two hyperinsulinemic 关insulin levels of 100 pmol/liter (low-dose clamp) and 400 pmol/liter (medium-dose clamp)兴 euglycemic (5 mmol/liter) clamps on two occasions: without or with lipopolysaccharide (LPS). Setting: The study was conducted at the Academic Medical Center, Metabolic and Clinical Research Unit (Amsterdam, The Netherlands). Participants: Eighteen healthy male volunteers participated in the study. Intervention: A hyperinsulinemic euglycemic (5 mmol/liter) clamp with LPS (two groups of six subjects; insulin infusion at rates of either 10 or 40 mU 䡠 m⫺2 䡠 min⫺1) or without LPS (n ⫽ 6; both insulin infusions in same subjects). Main Outcome Measure: We measured hepatic and peripheral insulin sensitivity. Results: Hepatic insulin sensitivity, defined as a decrease in endogenous glucose production during hyperinsulinemia (100 pmol/liter), was higher in the LPS group compared to the control group (P ⫽ 0.010). Insulin-stimulated peripheral glucose uptake was higher in both clamps after LPS compared to the control setting (P ⫽ 0.006 and 0.010), despite a significant increase in the plasma concentrations of norepinephrine and cytokines in the LPS group during both clamps. Conclusions: These data indicate that shortly (2 h) after administration of LPS, peripheral and hepatic insulin sensitivity increase. This may contribute to the hypoglycemia occurring in some patients with critical illness, especially in the setting of intensive insulin therapy. (J Clin Endocrinol Metab 94: 463–468, 2009)

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epsis and critical illness are associated with an acute and reversible state of insulin resistance, characterized by hyperglycemia. Hypoglycemia is also seen in critical illness as an infrequent feature of early sepsis (1–3). In animal studies, it is

known that hypoglycemia is the consequence of a decreased glucose production combined with a relative stimulation of glucose disposal by selective macrophage-rich tissues, mostly by an insulin-independent mechanism (4, 5). In humans, the pathophys-

ISSN Print 0021-972X ISSN Online 1945-7197 Printed in U.S.A. Copyright © 2009 by The Endocrine Society doi: 10.1210/jc.2008-0761 Received April 7, 2008. Accepted October 29, 2008. First Published Online November 4, 2008

Abbreviations: EGP, Endogenous glucose production; LPS, lipopolysaccharide; Ra, rate of appearance; Rd, rate of disappearance.

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J Clin Endocrinol Metab, February 2009, 94(2):463– 468

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LPS, Insulin, and Glucose Metabolism

iology of hypoglycemia during sepsis is unexplored. Because hypoglycemia is a rare and suddenly occurring event, requiring immediate glucose infusion, controlled studies with stable isotopes are not possible. However, iv administration of Gramnegative bacterial lipopolysaccharide (LPS) induces a systemic inflammatory response mimicking many of the clinical features associated with sepsis and can be administered safely in a welldefined manner to produce well-controlled effects (6). Only a few studies have actually measured aspects of whole body glucose metabolism in humans after administration of LPS (6 – 8). The study by Bloesch et al. (8) showed a significant decrease in plasma glucose concentration 2 h after LPS injection, followed by hyperglycemia. The decrease in glucose concentrations was ascribed to both a decrease in endogenous glucose production rate (rate of appearance of glucose/Ra) as well as an increase in peripheral glucose uptake (rate of disappearance/Rd). The changes in Ra and Rd of glucose, however, did not match in time with the short-lasting drop in plasma glucose concentrations (8). Agwunobi et al. (7) reported a significant increase in glucose infusion rate during a hyperinsulinemic euglycemic clamp 2 h after a LPS bolus, which they ascribed to an increase in peripheral glucose disposal. However, because they did not use isotopes to measure glucose fluxes, this explanation remains an assumption. The later phases of critical illness are characterized by insulin resistance, influencing the normal balance between glucose production and uptake. An aspect of the pathophysiology of hypoglycemia in early sepsis could be increased insulin sensitivity. This is especially relevant because it is more or less daily practice that severely ill patients, admitted to the intensive care unit, receive intensive insulin therapy to achieve euglycemia and start almost immediately with feeding, both resulting in hyperinsulinemia (9, 10). Because no data on insulin sensitivity in early sepsis in humans exists, we studied glucose metabolism with the use of stable isotopes during a hyperinsulinemic (100 pmol/liter and 400 pmol/ liter) euglycemic (5 mmol/liter) clamp in healthy male volunteers after LPS administration and in a control setting.

Subjects and Methods Subjects Eighteen healthy, nonsmoking, male volunteers were included. None of them used medication, had an infection in the preceding 3 months, was obese (defined as a body mass index ⬎25 kg/m2), or had a positive family history of diabetes. All volunteers had normal plasma values of fasting glucose concentration, erythrocyte sedimentation rate, complete blood count, lipid profile, creatinine, and liver enzymes, and all had a normal oral glucose tolerance test according to the American Diabetes Association criteria (11). The study was approved by the Medical Ethical Committee of the Academic Medical Center in Amsterdam, and all subjects gave written informed consent.

Protocol Volunteers (n ⫽ 18) were studied during euglycemia (5 mmol/liter) during either a plasma insulin level of 100 pmol/liter (low-dose hyperinsulinemic clamp) or an insulin level of 400 pmol/liter (medium-dose hyperinsulinemic clamp) to study hepatic and peripheral insulin sensitivity, respectively. In the control group, volunteers (n ⫽ 6) were studied


twice, i.e. during both clamps. Because it is not feasible to administer LPS twice to the same subjects, six volunteers underwent the low-dose hyperinsulinemic clamp concomitant with LPS, and six other volunteers underwent the medium-dose hyperinsulinemic clamp aimed at an insulin level of 400 pmol/liter plus LPS. The present study was part of a study on the differential effects of plasma glucose and insulin concentrations on several parameters relevant for critically ill patients (12–15). The data on glucose metabolism, measured with stable isotopes in the present study, have not been published earlier. For 3 d before the study, all volunteers consumed approximately 250 g of carbohydrates and were asked to refrain from vigorous exercise. Infusion protocols for the control and LPS groups have been published previously (12, 14). In short, at T ⫽ 0:00 (0800 h in the LPS group, and 0900 h in the control group), a blood sample was drawn for determination of background enrichment of plasma glucose. (The difference in time was due to a slight difference in study protocol.) Thereafter, a primed-continuous infusion of 关6,6-2H2兴glucose (prime, 8.0 ␮mol/kg; continuous, 0.11 ␮mol/kg 䡠 min; ⬎98% pure and ⬎99% enriched; ARC Laboratories BV, Apeldoorn, The Netherlands) together with somatostatin, glucagon, insulin (10 or 40 mU/m2 䡠 min) and glucose (10 or 20%) at a variable rate to maintain euglycemia (5 mmol/liter), was started and continued for 6 h in the control group and for 5 h in the LPS group. 关6,6-2H2兴glucose was added to the variable glucose infusion to minimize changes in the achieved plasma isotopic enrichment of approximately 1%. At T ⫽ 3:00 (after 3 h of clamping), LPS (Escherichia coli LPS) was administered to the LPS group (4 ng/kg).

Analytical procedures Plasma glucose was measured every 5 min at bedside from T ⫽ 0:00 until T ⫽ 6:00 in the control group and until T ⫽ 5:00 in the LPS group. From T ⫽ 2:20 until T ⫽ 3:00 and from T ⫽ 5:20 until T ⫽ 6:00 in the control group, and from T ⫽ 2:20 until T ⫽ 3:00 and T ⫽ 4:20 until T ⫽ 5:00 in the LPS group, five samples were drawn for measurement of glucose enrichment. The results of the glucose enrichments will be presented as mean of the five samples at T ⫽ 3:00 and at T ⫽ 5:00 (in the LPS group) or T ⫽ 6:00 (in the control group). Glucagon, insulin, cortisol, (nor)epinephrine, free fatty acid, and total adiponectin were measured at T ⫽ 3:00 and T ⫽ 6:00 in the control group and at T ⫽ 3:00 and T ⫽ 5:00 in the LPS group. IL-6, IL-8, IL-10, and TNF-␣ were measured at T ⫽ 6:00 in the control group and at T ⫽ 5:00 in the LPS group. Measurements of all these parameters and 关6,6-2H2兴glucose enrichment were performed as described before (12, 16).

Calculation and statistics Ra and Rd of glucose were calculated using the modified form of the Steele equations for non-steady-state measurements as described previously (17). Endogenous glucose production (EGP) was calculated as the difference between Ra glucose and glucose infusion rate. The change of EGP, Rd, and glucoregulatory hormones during the low-dose and the medium-dose hyperinsulinemic clamp (T ⫽ 6.00 compared with T ⫽ 3.00 in the control group, and T ⫽ 5:00 compared with T ⫽ 3:00 in the LPS group) were calculated and expressed as the relative (%) difference. Volunteer characteristics were compared using a Kruskal-Wallis test. For cytokines, single values measured during the low-dose and the medium-dose hyperinsulinemic clamp (T ⫽ 6.00 in the control group and T ⫽ 5:00 in the LPS group) were compared. All results were compared between the LPS and the control group using the Mann-Whitney U test. Data are presented as median 关range兴. Probability values of less than 0.05 were considered statistically significant. SPSS statistical software version 12.0.1 (SPSS Inc., Chicago, IL) was used to analyze the data.

4.9 关4.6 –5.0兴 307 关277– 483兴 6.6 关6.1–11.8兴 0.02 关0.02– 0.03兴 0.69 关0.41– 0.82兴 0.07 关0.05– 0.14兴 52 关32–71兴 252 关142–306兴 2.9 关0.0 –5.0兴 55.1 关40.0 –71.3兴 P ⬍ 0.05 when comparing T ⫽ 6:00 or T ⫽ 5:00 to T ⫽ 3:00 within the control or LPS groups. a

Data are expressed as median 关range兴, n ⫽ 6 per group. T, Time; FFA, free fatty acids.

5:00 3:00 6:00

5.0 关4.6 –5.3兴 431 关332– 487兴 5.4关2.8 –7.2兴a 0.02 0.90 关0.47–1.24兴 0.08 关0.05– 0.23兴 54 关44 – 82兴 206 关124 –312兴 0.3 关0.0 –3.8兴 58.4 关51.9 – 66.5兴 4.9 关4.7–5.2兴 436 关332– 463兴 5.6 关2.9 – 8.0兴 0.02 关0.02– 0.05兴 0.77 关0.42–1.76兴 0.08 关0.05– 0.14兴 59 关52–92兴 163 关115–287兴 0.3 关0.0 –3.4兴 54.1 关44.0 – 67.2兴

3:00 5:00 6:00

5.1 关5.0 –5.4兴a 93 关80 –106兴 4.5 关3.8 – 6.5兴a 0.02 关0.02– 0.03兴 0.95 关0.71–3.74兴 0.06 关0.05– 0.18兴 58 关49 –99兴 211 关183– 497兴 4.2 关2.9 –7.3兴a 31.0关25.0 –34.5兴a

3:00

4.8 关4.7–5.0兴 93 关80 –123兴 4.8 关4.2–7.7兴 0.02 关0.02– 0.03兴 1.14 关0.46 –10.2兴 0.06 关0.05– 0.21兴 63 关42–102兴 199 关73–355兴 10.0 关6.0 –16.3兴 28.2 关18.1–33.5兴

T

3:00

5.1 关4.6 –5.5兴 70 关58 – 84兴a 7.6 关4.2–11.5兴 0.04 关0.02– 0.09兴 3.01 关0.91– 4.17兴a 0.19 关0.07– 0.59兴 42 关26 –55兴 530 关463– 674兴a 1.5 关0.9 –1.7兴a 35.4 关20.2– 64.8兴a

LPS group

Medium-dose hyperinsulinemic clamp

Control group

Glucose (mmol/liter) Insulin (pmol/liter) Total adiponectin (␮g/ml) FFA (mmol/liter) Norepinephrine (nmol/liter) Epinephrine (nmol/liter) Glucagon (ng/liter) Cortisol (nmol/liter) EGP (␮mol/kg 䡠 min) Rd (␮mol/kg 䡠 min)

Glucoregulatory hormones during the low-dose and the medium-dose hyperinsulinemic clamp in the control group and the LPS group (Table 1) At T ⫽ 3:00 during the low-dose and the medium-dose hyperinsulinemic clamp, there was no difference in plasma concentration of any of the hormones between the control and the LPS group. During the low-dose clamp in the control group, plasma concentration of total adiponectin decreased significantly by 7%. In the LPS group during the low-dose hyperinsulinemic clamp, norepinephrine and cortisol significantly increased by 296 and 250%, respectively. The increase in plasma concentration of norepinephrine in the LPS group was significantly higher compared with the 11% decrease of plasma norepinephrine concentration in the control group (P ⫽ 0.006). During the medium-dose hyperinsulinemic clamp in the control group, plasma concentration of total adiponectin decreased

LPS group

Glucose kinetics during the medium-dose hyperinsulinemic clamp in the control group and the LPS group (Table 1) Euglycemia was maintained in all clamps. At T ⫽ 3:00, glucose concentration, EGP, and Rd in the control group and the LPS group were similar. In the control group, EGP and Rd remained similar between T ⫽ 3:00 and T ⫽ 6:00. In the LPS group between T ⫽ 3:00 and T ⫽ 5:00, EGP was unaffected 2 h after LPS. Rd increased significantly by 53% 2 h after LPS. This relative increase in Rd in the LPS group was significantly higher compared with the relative increase in Rd in the control group (12%) (P ⫽ 0.010).

Low-dose hyperinsulinemic clamp

Glucose kinetics during the low-dose hyperinsulinemic clamp in the control group and the LPS group (Table 1) Euglycemia was maintained during all clamps. At T ⫽ 3:00 (just before LPS administration), glucose concentrations, EGP, and Rd in the control and the LPS group were similar. In the control subjects between T ⫽ 3:00 and T ⫽ 6:00, EGP decreased significantly by 55% and Rd increased significantly by 5%. In the LPS-treated subjects, EGP decreased significantly after LPS administration by 82%. Rd increased significantly after LPS infusion by 75%. In the LPS group, the relative decrease in EGP and the relative increase in peripheral glucose disposal were significantly higher compared with those values in the control group (P ⫽ 0.010 and 0.006, respectively).

Control group

Subjects characteristics Subjects in the control group and the LPS group (low-dose and medium-dose hyperinsulinemic clamp, respectively) were similar in all aspects; age (in years), 22 关22–23兴 vs. 23 关23–25兴 and 25 关21–27兴, respectively; body mass index (kg/m2), 21.7 关21.0 –23.4兴 vs. 22.0 关19.9 –23.6兴 and 22.1 关20.9 –23.7兴, respectively.

TABLE 1. Glucoregulatory hormones and glucose kinetics during the low-dose and medium-dose hyperinsulinemic euglycemic (5 mmol/liter) clamps in the control and LPS groups

Results

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5.1 关4.7–5.5兴 260 关234 –360兴a 6.5 关6.1–10.6兴 0.03 关0.02– 0.03兴 2.20 关1.41– 6.18兴a 0.23 关0.06 – 0.48兴a 48.关27–56兴 545 关510 – 646兴a 2.0 关0.0 –5.0兴 80.2 关66.9 –115.4兴a


4.9 关4.6 –5.1兴 96 关62–122兴 7.2 关4.6 –11.5兴 0.02 关0.02– 0.09兴 0.73 关0.49 –1.07兴 0.08 关0.05– 0.09兴 50 关21– 81兴 170 关54 –295兴 8.9 关4.9 –17.8兴 21.4 关14.9 –36.9兴


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TABLE 2. Plasma cytokine concentrations during the low-dose and medium-dose hyperinsulinemic euglycemic (5 mmol/liter) clamps in the control (T ⫽ 6:00 h) and LPS (T ⫽ 5:00 h) groups Low-dose hyperinsulinemic clamp TNF-␣ (pg/ml) IL-6 (pg/ml) IL-8 (pg/ml) IL-10 (pg/ml)

Medium-dose hyperinsulinemic clamp

Control group

LPS group

Control group

LPS group

3 关3–302兴 3 关3– 498兴 13 关9 –755兴 3 关3–28兴

10,002 关4,055–38,158兴a 2,556 关1,962–10,555兴a 32,78 关2,162– 4,378兴a 53 关37–76兴a

3 关3–173兴 5 关3–341兴 10 关7– 460兴 3 关3–15兴

10,610 关6,266 –19,583兴a 2,948 关1,809 – 4,868兴a 3143 关2181– 4304兴a 69 关24 –300兴a

Data are expressed as median 关range兴, n ⫽ 6 per group. a

P ⬍ 0.05 when comparing the LPS group to the control group.

significantly by 6%. In the LPS group, during the medium-dose clamp, there was a significant decrease in plasma insulin concentration of 19% and a significant increase in plasma norepinephrine, epinephrine, and cortisol concentration by 413, 243, and 153%, respectively. This decrease in the plasma insulin concentration and the increase of the norepinephrine concentration in the LPS group were significantly higher compared with the increase of plasma insulin concentration (3%) and the plasma norepinephrine concentration (11%) in the control group (both P ⫽ 0.004). Cytokines during the low-dose and the medium-dose hyperinsulinemic clamp in the control and the LPS group (Table 2) During the low-dose and the medium-dose hyperinsulinemic clamp, all cytokines were significantly higher in the LPS group compared with the control group.

Discussion In early sepsis (i.e. during the first hours), hypoglycemia is an infrequent feature, whereas hyperglycemia is a more common phenomenon in later stages (1–3). The shift of hypoglycemia to hyperglycemia is not completely explained, but it is assumed that increased need for substrate availability for repair of damaged tissues or tissues with an increased need (immune system) is the driving force. The pathophysiological mechanism underlying hypoglycemia is unknown and cannot be investigated in clinical sepsis because it has to be corrected instantaneously. Administration of LPS, which initiates a systemic inflammation (fever, headache, tachycardia, and stress hormone responses), can be used as a validated model to mimic the clinical presentation of bacterial sepsis. In the present study, we show that administration of LPS results in an increase in peripheral and hepatic insulin sensitivity. Our data on EGP and Rd during insulin clamps extend prior assumptions about LPS-induced glucose kinetics that the decrease in plasma glucose concentration 2 h after LPS is due to an increased Rd as well as a decrease in EGP (8). The decrease in EGP is a phenomenon found previously in animal studies (5). Theoretically this decrease could be caused by either a depletion of glycogen or a decrease in gluconeogenesis and/or glycogenolysis. The explanation may be due to a lack of substrate (such as alanine), a change in activity of glucose transporters in hepatocytes, or an acute inhibition of enzymes

involved in these processes (18, 19). Although decreased expression of genes encoding for important gluconeogenetic enzymes, such as posphoenolpyruvate carboxykinase and glucose-6-phosphatase, has been reported after long-term exposure to LPS, this seems less likely in our acute experiments (20, 21). The increased Rd can be the result of an increase in insulin and/or non-insulin-mediated glucose uptake. In rodents, it has been shown that LPS directly stimulates non-insulin-mediated glucose uptake by macrophage-rich tissue. However, indirect stimulation of glucose uptake via an increase in LPS-induced circulating factors with insulin-like properties, such as cytokines, cannot be ruled out (4). As expected, after the administration of LPS, all plasma cytokine concentrations were significantly higher compared with the control group. The role of these inflammatory mediators is still controversial. On the one hand, TNF-␣, IL-6, IL-8, and IL-10 are associated with insulin resistance, which hampers peripheral glucose uptake (22–24). On the other hand, infusion of TNF-␣ and IL-6 is known to enhance Rd glucose, indicating a possible role for these mediators (25–28). However, because the infusion of IL-6 has previously shown to increase EGP, whereas TNF-␣ did not affect EGP, these factors cannot fully explain the increased insulin sensitivity found in our study (26, 28). The decrease of total plasma adiponectin concentrations in the control group during hyperinsulinemia is a known phenomenon (15). Although the change in plasma adiponectin levels did not differ between the LPS and the control group, the blunted decrease in adiponectin upon insulin infusion after administration of LPS may contribute to the higher Rd and the lower EGP in this group. Norepinephrine induces insulin resistance and can explain neither the increased Rd nor the decreased EGP in the LPS group (29, 30). A potential confounding factor in our study might be the 1-h difference in insulin infusion between the LPS group and the control group. However, this is an unlikely explanation for our results. It is known that the effect of insulin infusion increases in time (i.e. lower EGP and higher Rd) (31). The results of our study, however, show the opposite: in the group with the longest duration of insulin infusion (the control group), suppression of EGP was less and Rd was lower compared with the group with the shorter duration of insulin infusion (the LPS group). The same holds true for the lower insulin concentrations obtained in the LPS group. For the decreased plasma insulin con-


centrations, an increased clearance, rather than a decreased production, seems an explanation (32). The decrease in plasma insulin concentration, however, does not contradict our conclusion; as with similar insulin concentrations (i.e. the higher concentrations in the control group), the differences in Rd and EGP between groups probably would have been even more pronounced. In the control group during the low-dose hyperinsulinemic 5 mmol/liter clamp, plasma glucose concentration at T ⫽ 6:00 was significantly, but only slightly (0.3), higher than at T ⫽ 3:00. Although statistically significant, we do not consider this small difference to be relevant. In addition, it does not falsify our data because higher plasma concentrations of glucose stimulate Rd via mass effect. Because Rd was lower in the control group, the difference between control group and LPS group would therefore probably have been more significant in the case of equal glucose concentrations. LPS injection into healthy humans results in a transient rise in body temperature. In this respect, it is important to note that this rise only occurred from 2 h after LPS injection onward and to a similar extent in all LPS groups (data not shown). Hence, changes in body temperature are unlikely to have influenced our results. The studies were done in relatively young, lean males. Our results are therefore not necessarily applicable to insulin-resistant subjects, like overweight or elderly patients. Furthermore, the model of LPS used in this experiment might induce more transient changes than are probably the case in “real” sepsis. It is unknown whether LPS- and sepsis-induced hypoglycemia share the same mechanism. In conclusion, as an extension to earlier studies, the results of our study show that 2 h after administration of LPS, peripheral and hepatic insulin sensitivity increase. This is of particular importance because, nowadays, most severely ill patients admitted to the intensive care unit receive intensive insulin therapy to achieve euglycemia and start on feeding very early on, resulting in exogenous and endogenous hyperinsulinemia, respectively. This clinical setting in combination with the increased biological effects of insulin during LPS-induced sepsis may put the patients at risk for developing hypoglycemia and in fact may explain the incidence of hypoglycemia seen in septic patients during intensive insulin treatment (9). Unraveling the mechanism through which LPS establishes this effect seems helpful in treating patients by stabilizing glucose metabolism in sepsis.

Acknowledgments We thank A. F. C. Ruiter, B. C. E. Voermans, and the staff of the Clinical Research Unit of our hospital for their indispensable help during the experiments. Address all correspondence and requests for reprints to: S. N. van der Crabben, University Medical Center Utrecht (Wilhelmina Children’s Hospital), DBG Department of Clinical Genetics, KC. 04.084.2, Lundlaan 6, P.O. Box 85090, 3508 AB Utrecht, The Netherlands. E-mail: [email protected]. Disclosure Statement: S.N.v.d.C., R.M.E.B., M.T.A., E.E., M.W.T.T., M.J.S., T.v.d.P., and H.P.S. have nothing to disclose. M.E.S. has received a grant from the Dutch Diabetes Research Foundation (no. 2002.00.008).


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References 1. Romijn JA, Sauerwein HP 1988 Hypoglycaemia induced by septic shock. Neth J Med 33:68 –73 2. Romijn JA, Godfried MH, Wortel C, Sauerwein HP 1990 Hypoglycemia, hormones and cytokines in fatal meningococcal septicemia. J Endocrinol Invest 13:743–747 3. Miller SI, Wallace Jr RJ, Musher DM, Septimus EJ, Kohl S, Baughn RE 1980 Hypoglycemia as a manifestation of sepsis. Am J Med 68:649 – 654 4. Lang CH, Dobrescu C 1991 Sepsis-induced increases in glucose uptake by macrophage-rich tissues persist during hypoglycemia. Metabolism 40:585– 593 5. Lang CH, Spolarics Z, Ottlakan A, Spitzer JJ 1993 Effect of high-dose endotoxin on glucose production and utilization. Metabolism 42:1351–1358 6. Fong Y, Matthews DE, He W, Marano MA, Moldawer LL, Lowry SF 1994 Whole body and splanchnic leucine, phenylalanine, and glucose kinetics during endotoxemia in humans. Am J Physiol 266:R419 –R425 7. Agwunobi AO, Reid C, Maycock P, Little RA, Carlson GL 2000 Insulin resistance and substrate utilization in human endotoxemia. J Clin Endocrinol Metab 85:3770 –3778 8. Bloesch D, Keller U, Spinas GA, Kury D, Girard J, Stauffacher W 1993 Effects of endotoxin on leucine and glucose kinetics in man: contribution of prostaglandin E2 assessed by a cyclooxygenase inhibitor. J Clin Endocrinol Metab 77:1156 –1163 9. Brunkhorst FM, Engel C, Bloos F, Meier-Hellmann A, Ragaller M, Weiler N, Moerer O, Gruendling M, Oppert M, Grond S, Olthoff D, Jaschinski U, John S, Rossaint R, Welte T, Schaefer M, Kern P, Kuhnt E, Kiehntopf M, Hartog C, Natanson C, Loeffler M, Reinhart K 2008 Intensive insulin therapy and pentastarch resuscitation in severe sepsis. N Engl J Med 358:125–139 10. van den Berghe G, Wouters P, Weekers F, Verwaest C, Bruyninckx F, Schetz M, Vlasselaers D, Ferdinande P, Lauwers P, Bouillon R 2001 Intensive insulin therapy in the critically ill patients. N Engl J Med 345:1359 –1367 11. 2008 Diagnosis and classification of diabetes mellitus. Diabetes Care 31(Suppl 1): S55–S60 12. Stegenga ME, van der Crabben SN, Blumer RM, Levi M, Meijers JC, Serlie MJ, Tanck MW, Sauerwein HP, van der Poll T 2008 Hyperglycemia enhances coagulation and reduces neutrophil degranulation, whereas hyperinsulinemia inhibits fibrinolysis during human endotoxemia. Blood 112:82– 89 13. Stegenga ME, van der Crabben SN, Dessing MC, Pater JM, van den Pangaart PS, de Vos AF, Tanck MW, Roos D, Sauerwein HP, van der Poll T 2008 Effect of acute hyperglycaemia and/or hyperinsulinaemia on proinflammatory gene expression, cytokine production and neutrophil function in humans. Diabet Med 25:157–164 14. Stegenga ME, van der Crabben SN, Levi M, de Vos AF, Tanck MW, Sauerwein HP, van der Poll T 2006 Hyperglycemia stimulates coagulation, whereas hyperinsulinemia impairs fibrinolysis in healthy humans. Diabetes 55: 1807–1812 15. Blumer RM, van der Crabben SN, Stegenga ME, Tanck MW, Ackermans MT, Endert E, van der Poll T, Sauerwein HP 2008 Hyperglycemia prevents the suppressive effect of hyperinsulinemia on plasma adiponectin levels in healthy humans. Am J Physiol Endocrinol Metab 295:E613—E617 16. Soeters MR, Sauerwein HP, Groener JE, Aerts JM, Ackermans MT, Glatz JF, Fliers E, Serlie MJ 2007 Gender-related differences in the metabolic response to fasting. J Clin Endocrinol Metab 92:3646 –3652 17. Finegood DT, Bergman RN, Vranic M 1988 Modeling error and apparent isotope discrimination confound estimation of endogenous glucose production during euglycemic glucose clamps. Diabetes 37:1025–1034 18. Spolarics Z, Pekala PH, Bagby GJ, Spitzer JJ 1993 Brief endotoxemia markedly increases expression of GLUT1 glucose transporter in Kupffer, hepatic endothelial and parenchymal cells. Biochem Biophys Res Commun 193: 1211–1215 19. Meinz H, Lacy DB, Ejiofor J, McGuinness OP 1998 Alterations in hepatic gluconeogenic amino acid uptake and gluconeogenesis in the endotoxin treated conscious dog. Shock 9:296 –303 20. Yerkovich ST, Rigby PJ, Fournier PA, Olynyk JK, Yeoh GC 2004 Kupffer cell cytokines interleukin-1␤ and interleukin-10 combine to inhibit phosphoenolpyruvate carboxykinase and gluconeogenesis in cultured hepatocytes. Int J Biochem Cell Biol 36:1462–1472 21. Deutschman CS, Andrejko KM, Haber BA, Bellin L, Elenko E, Harrison R, Taub R 1997 Sepsis-induced depression of rat glucose-6-phosphatase gene expression and activity. Am J Physiol 273:R1709 –R1718 22. Shoelson SE, Lee J, Goldfine AB 2006 Inflammation and insulin resistance. J Clin Invest 116:1793–1801 23. den Boer MA, Voshol PJ, Schroder-van der Elst JP, Korsheninnikova E, Ouwens DM, Kuipers F, Havekes LM, Romijn JA 2006 Endogenous

468

24.

25.

26.

27.



interleukin-10 protects against hepatic steatosis but does not improve insulin sensitivity during high-fat feeding in mice. Endocrinology 147: 4553– 4558 Bruun JM, Verdich C, Toubro S, Astrup A, Richelsen B 2003 Association between measures of insulin sensitivity and circulating levels of interleukin-8, interleukin-6 and tumor necrosis factor-␣. Effect of weight loss in obese men. Eur J Endocrinol 148:535–542 Lang CH, Dobrescu C, Bagby GJ 1992 Tumor necrosis factor impairs insulin action on peripheral glucose disposal and hepatic glucose output. Endocrinology 130:43–52 Stouthard JM, Romijn JA, van der Poll T, Endert E, Klein S, Bakker PJ, Veenhof CH, Sauerwein HP 1995 Endocrinologic and metabolic effects of interleukin-6 in humans. Am J Physiol 268:E813–E819 Carey AL, Steinberg GR, Macaulay SL, Thomas WG, Holmes AG, Ramm G, Prelovsek O, Hohnen-Behrens C, Watt MJ, James DE, Kemp BE, Pedersen BK, Febbraio MA 2006 Interleukin-6 increases insulin-stimulated glucose disposal


28.

29.

30.

31.

32.

in humans and glucose uptake and fatty acid oxidation in vitro via AMPactivated protein kinase. Diabetes 55:2688 –2697 Sakurai Y, Zhang XJ, Wolfe RR 1996 TNF directly stimulates glucose uptake and leucine oxidation and inhibits FFA flux in conscious dogs. Am J Physiol 270:E864 –E872 Darmon P, Dadoun F, Boullu-Ciocca S, Grino M, Alessi MC, Dutour A 2006 Insulin resistance induced by hydrocortisone is increased in patients with abdominal obesity. Am J Physiol Endocrinol Metab 291:E995–E1002 Lembo G, Capaldo B, Rendina V, Iaccarino G, Napoli R, Guida R, Trimarco B, Sacca L 1994 Acute noradrenergic activation induces insulin resistance in human skeletal muscle. Am J Physiol 266:E242–E247 Soop M, Nygren J, Brismar K, Thorell A, Ljungqvist O 2000 The hyperinsulinaemic-euglycaemic glucose clamp: reproducibility and metabolic effects of prolonged insulin infusion in healthy subjects. Clin Sci (Lond) 98:367–374 Dahn MS, Lange MP, Mitchell RA, Lobdell K, Wilson RF 1987 Insulin production following injury and sepsis. J Trauma 27:1031–1038