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Psychiatry and Clinical Neurosciences 2009; 63: 639–645

doi:10.1111/j.1440-1819.2009.02004.x

Regular Article

Total antioxidant capacity and total oxidant status in patients with major depression: Impact of antidepressant treatment pcn_2004

639..645

Birgul Elbozan Cumurcu, MD,1* Huseyin Ozyurt, Suleyman Demir, MD1 and Rifat Karlidag, MD4

MD,2

Ilker Etikan,

PhD,3

Departments of 1Psychiatry, 2Biochemistry and 3Biostatistics, Gaziosmanpasa University School of Medicine, Tokat and 4 Department of Psychiatry, Inonu University Medical Faculty, Turgut Ozal Medical Center, Malatya, Turkey

Aim: The purpose of the present study was to investigate whether total antioxidant capacity (TAC) and total oxidant status (TOS) are associated with major depressive disorder (MDD) and to evaluate the impact of antidepressant treatment on TAC and TOS in MDD. Methods: Fifty-seven MDD patients and 40 healthy controls participated in the study. Serum TAC and TOS were measured both in patients and controls using Erel’s methods. Patients were treated with antidepressant drugs for 12 weeks. The treatment course was evaluated using the Montgomery– Asberg Depression Rating Scale (MADRS) in all patients. Results: TOS and oxidative stress index (OSI) were higher (P = 0.0001 for both) and TAC was lower (P = 0.0001) in the MDD group compared with those

EACTIVE OXYGEN SPECIES (ROS) such as hydroxyl radical and superoxide radical are reactive chemical species generated during normal metabolic processes and, in excess, can damage lipids and proteins.1 ROS cause peroxidation of cell membrane double-chain fatty acids and then cellular injury, and

R

*Correspondence: Birgul Elbozan Cumurcu, MD, Gaziosmanpas¸a Üniversitesi, Tıp Fakültesi, Psikiyatri Anabilim Dalı, 60100 Tokat, Turkey. Email: [email protected] Received 6 August 2008; revised 18 May 2009; accepted 20 May 2009.

of the controls. After 3 months of antidepressant treatment, TOS and OSI were decreased and TAC was increased compared with the pretreatment values (P = 0.0001, for all). Furthermore, there were significant positive correlations between the severity of the disease and serum TOS and OSI (r = 0.584, P = 0.0001; r = 0.636, P = 0.0001, respectively). A negative correlation was found between the severity of the disease and serum TAC (r = -0.553, P = 0.0001) at the pre-treatment stage.

Conclusion: Treatment administered for 3 months to MDD patients increases TAC while decreasing TOS and OSI. Key words: antidepressant treatment, major depressive disorder, total antioxidant capacity, total oxidant status.

also increase oxidative stress.2,3 Under physiological conditions there is a balance between oxidative and antioxidative systems in the organism. Oxidative stress is the imbalance between these systems in favor of the former and has been implicated in the pathophysiology of several neuropsychiatric diseases, including major depressive disorder (MDD).4–7 Many researchers specializing in this area have focused on the relationship of oxidant and antioxidant systems with depression in the last decade, and interesting results have been published.5–12 To our knowledge there have been only two studies that investigated total antioxidant capacity (TAC) in MDD patients6,13 and several others evaluating

© 2009 The Authors Journal compilation © 2009 Japanese Society of Psychiatry and Neurology

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oxidative and antioxidative parameters (e.g. adenosine deaminase [ADA], xanthine oxidase [XO], superoxide dismutase [SOD], glutathione peroxidase [GPx] and nitric oxide [NO]).5,7,9–12 Studies investigating the oxidative and antioxidative systems in MDD are limited and there is little information available about the effects of antidepressants on these systems.6,14,15 TAC is a useful estimate of the activity of antioxidants in a medium.16 Measurement of TAC can provide information on an individual’s overall antioxidant status, which may include those antioxidants not yet recognized or not easily measured.17 Serum concentrations of different oxidant species can be measured separately in laboratories, but the measurements are time-consuming, labor-intensive and costly and require complicated techniques.18 The aim of the present study was therefore to evaluate TAC and TOS in patients with MDD and to investigate effects of selective serotonin re-uptake inhibitors (SSRI) on these systems.


mic or anxiety disorder or patients with a significant suicide risk were excluded. Patients with a history of known major health problems (such as cardiovascular, endocrine, metabolic system disorders or stroke) or abnormal routine blood tests (complete blood count, serum electrolyte assay, liver function tests and thyroid function tests) were also excluded. Control subjects were excluded for past, present and family history of psychiatric disorders or chronic systemic disease (such as cardiovascular, endocrine, metabolic system disorders or stroke). Exclusion for family history of psychiatric disorders depended on an extensive questioning of subjects. None of the patients or individuals in the control group had been on any medication for the last 3 months. None of the patients or control subjects had suffered from substance abuse or addiction in the last year. In addition, there were no smokers in the patient or control group. Blood was obtained from the patient and control groups in the fasting state because serum TAC could increase post-prandially.23

METHODS Procedures Subjects Fifty-seven patients (46 female, 11 male; mean age, 35.47 ⫾ 12.05 years), who had presented at the Psychiatry Outpatient Clinic of Gaziosmanpasa University Medical Faculty were included in the study. All cases were evaluated by a psychiatrist on the basis of the Structured Clinical Interview for DSM-IV–Clinical Version (SCID-I/CV),19 Turkish version,20 and diagnosed with MDD. Forty age- and sex-matched control subjects (33 female, seven male; mean age, 35.17 ⫾ 11.81 years) were recruited from the hospital or university staff. Control subjects were also evaluated using the SCIDI/CV to exclude any psychiatric illness. This study was designed as a prospective case–control study and written informed consent was obtained from each patient after a complete description of the study. The study conformed to the articles of the Declaration of Helsinki. Depressive symptoms were explored using Montgomery–Asberg Depression Rating Scale (MADRS).21 The scale has been found valid and reliable in Turkish.22 The patients were required to have a score of least 30 at baseline on the MADRS. Patients with an Axis I disorder other than MDD or with an Axis II disorder, as well as patients who had MDD with psychotic features, bipolar, cyclothymic, dysthy-

After 12 weeks of treatment, 57 patients could be assessed together with 40 age- and sex-matched healthy controls. Throughout the study, the patients were assessed seven times: on the day of the screening visit (7th day), at baseline (day 0), and on the 21st (second visit), 42nd (third visit), 56th (fourth visit), 76th (fifth visit) and 90th day (sixth visit). In patients with major depression, TAC and TOS were tested in venous blood samples at baseline and after treatment with SSRI for 3 months. Fasting blood (>12 h) was drawn at 09.00 hours (⫾10 min) for all subjects. Initial MADRS scores showed moderate depression in 28 and severe depression in 29 patients but all patients had recovered at the end of 3 months, when recovery was defined as a MADRS score ⱕ9. The timerelated MADRS score changes during treatment are given in Figure 1. The antidepressant drugs used were sertraline in 27 (47.4%), paroxetine in 20 (35.1%), and escitalopram in 10 patients (17.5%). The average duration of MDD was 21.49 ⫾ 2.14 months. Patients with MDD were treated with sertraline 50 mg/day, or paroxetine 20 mg/day or escitalopram 10 mg/day according to their symptoms. Sertraline was increased to 100 mg/ day, paroxetine to 40 mg/day and escitalopram to 20 mg/day according to the clinical condition of the patients on the second visit. Control subjects were



40

MADRS score

30

20

10

0

0

7

21

42 Days

56

76

90

Figure 1. Change of patient Montgomery-Asberg Depression Rating Scale (MADRS) scores during treatment.

assessed on a semi-structured psychiatric interview and the same laboratory test protocol was used. The severity of depressive symptoms was assessed using the MADRS. The reason why MADRS was preferred was its sensitive measurement of depressive symptom changes in therapeutic studies.24 MADRS was administered on days 0, 7, 21, 42, 56, 76 and 90. The MDD group was classified according to the MADRS scores as moderate MDD (MDRS: 29–35, n = 28) or severe MDD (MADRS: ⱖ36, n = 29). Response to an antidepressant was defined as a ⱖ50% decrease in MADRS scores compared to the baseline value, and remission was defined as MADRS score ⱕ9. On the 42nd day, 48 patients were responders (84.21%) and six were non-responders (14.03%). All the patients were found to be in remission at the end of week 12, the end of the study. Venous blood samples (5 mL) were collected from patients and controls for measurement of serum TAC and TOS. The samples were centrifuged within 1 h, stored at -70°C and analyzed within 2 months. The TAC of serum was measured using automated colorimetry method of Erel.25 The performance characteristics of the biochemical method were between 1.22 and 2.05 for within-batch measurements [coefficient of variation (CV%)], and the measurements for within-batch days (CV%) were between 1.21 and 2.13. An automated analyzer, RxL Max (Dimension

TAC and TOS in major depression

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Clinical Chemistry system, Dade Behring, Newark, NJ, USA) was used. In this procedure the hydroxyl radical, the most potent biological radical, is produced by the Fenton reaction and reacts with the colorless substrate O-dianisidine to produce the dianisyl radical, which is bright yellowish-brown in color. Upon the addition of a serum sample, the oxidative reactions initiated by the hydroxyl radicals present in the reaction mix are suppressed by the antioxidant components of the serum, preventing the color change and thereby providing an effective measure of the TAC of the serum. The assay results are expressed as mmol Trolox equiv/L. The TOS of serum was measured using the automated colorimetry method of Erel (2005).26 The performance characteristics of the biochemical method were within- and between-between batch measurements (CV%), and they were lower than 3%. An automated analyzer, RxL Max (Dimension Clinical Chemistry system), was used. In this procedure the oxidants present in the sample oxidize the ferrous ion–dianisidine complex to ferric ion. The oxidation reaction is enhanced by glycerol molecules, which are abundant in the reaction medium. The ferric ion makes a colored complex with xylenol orange in an acidic medium. The color intensity, which can be measured spectrophotometrically, is related to the total amount of oxidant molecules (e.g. lipids, proteins) present in the sample. The assay is calibrated with hydrogen peroxide, and the results are expressed in terms of micromolar hydrogen peroxide equivalent per liter (mmol H2O2 equiv/L). The TOS : TAC ratio was used as the oxidative stress index (OSI). To perform the calculation, the units of TAC, mmol Trolox equivalent/L, was converted to mmol Trolox equivalent/L, and OSI was calculated as follows: OSI = [(TOS, mmol/L) / (TAC, mmol Trolox equivalent/L) / 100].27

Statistical analysis The t-test for paired samples was used to compare dependent variables. The t-test for unpaired samples was used to compare independent variables. Simple correlation analysis (Pearson correlation coefficient) was used to compare continuous variables. Discontinuous variables were compared using the c2 test.

RESULTS There were no significant differences (P > 0.05) in age or male/female ratio between patients and controls.


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Table 1. Comparison of pre-treatment with control group and of pre-treatment with post-treatment group (mean ⫾ SD)

I-Pre-treatment MDD group (n = 57) II-Control group (n = 40) III-Post-treatment MDD group (n = 57) Comparison of I–II P† Comparison of I–III

TAC (mmol Troloxequiv./L)

TOS (mmol H2O2 equiv./L)

OSI (Arbitrary unit)

1.10 ⫾ 0.17 1.31 ⫾ 0.07 1.16 ⫾ 0.14 0.0001 0.0001

16.30 ⫾ 2.57 12.24 ⫾ 3.36 14.46 ⫾ 2.13 0.0001 0.0001

0.15 ⫾ 0.03 0.09 ⫾ 0.02 0.12 ⫾ 0.02 0.0001 0.0001

†

Test for paired samples. MDD, major depressive disorder; OSI, oxidative stress index; TAC, total antioxidant capacity; TOS, total oxidant status.

Serum TAC and TOS of healthy control and MDD patients are given in Table 1. The serum TOS and OSI were significantly higher and TAC significantly lower in the pre-treatment stage in MDD patients compared to the healthy control group (P = 0.0001). Comparison of pre- and post-treatment TOS, TAC and OSI indicated a statistically significant decrease in TOS and OSI (P = 0.0001) and a statistically significant increase in TAC (P = 0.0001) after treatment. When we analyzed the correlation between the MADRS scores and serum TOS, TAC and OSI, a significant positive correlation was found between the severity of the disease and serum TOS and OSI (r = 0.584, P = 0.0001; r = 0.636, P = 0.0001, respectively); a negative correlation was found between the severity of disease and serum TAC in the pretreatment stage (r = -0.553, P = 0.0001). Figure 2(a) shows the positive correlation between serum TOS and disease severity, while Fig. 2(b) shows the positive correlation of OSI and disease severity. Figure 2(c) shows the negative correlation between serum TAC and disease severity. There were no significant differences between the three antidepressant treatments in pre-treatment values and percent changes of the parameters (data not shown). We analyzed the change in TAC, TOS and OSI in the sertraline, paroxetine and escitalopram treatment groups separately. In the sertraline group, treatment caused a significant decrease in TOS and OSI (P = 0.01, P = 0.002, respectively), together with an increase in TAC, but this change was not significant (P = 0.109). In the paroxetine group, treatment caused a significant decrease in TOS and OSI (P = 0.0001, P = 0.0001, respectively) and a significant increase in TAC (P = 0.001). In the escitalopram group, treatment caused a significant decrease in TOS and OSI (P = 0.009, P = 0.003, respectively) and a significant increase in TAC (P = 0.028).

Table 2 shows the responder and non-responder TAC–TOS changes on the 42nd day. Comparison of responders and non-responders on the 42nd day for pre-treatment values and percent changes of TAC– TOS indicated a statistically significant TAC increase (t = 3.657, P = 0.001), together with a statistically significant TOS decrease (t = 6.721, P = 0.0001) in responders. The non-responders showed no significant difference when the pre-treatment and percent change of TAC and TOS were compared (t = 1.402, P = 0.198; t = 1.109, P = 0.300, respectively).

DISCUSSION The major findings of the present study were that (i) serum TOS and OSI were significantly higher and TAC significantly lower in the pre-treatment stage in MDD patients compared to the healthy control group; (ii) serum TOS and OSI were significantly decreased and TAC significantly increased in the posttreatment stage compared to the pre-treatment stage in MDD patients; (iii) there was a significant positive correlation between the severity of the disease and serum TOS and OSI; we also found a negative correlation between the severity of the disease and serum TAC in the pre-treatment stage; and (iv) serum TOS, TAC and OSI were influenced by the treatment but to different degrees by different antidepressants (sertraline, paroxetine, escitalopram). Sofic et al. reported no change in serum antioxidant capacity13 while Sarandol et al. found decreased serum TAC in patients with MDD.6 We found low serum TAC in MDD patients, similar to Sarandol et al.6 Sarandol et al. reported a significant positive correlation between the severity of the disease and SOD activity.6 In parallel to their results, Bilici et al. reported a significant and positive correlation between severity of disease and erythrocyte SOD



(a)

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0.80

1.40

Figure 2. Montgomery-Asberg Depression Rating Scale (MADRS) scores and (a) serum total oxidant status (TOS); (b) oxidative stress index (OSI) and (c) serum total antioxidant capacity (TAC).


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activity and suggested that increased severity of depression increases the antioxidant enzyme levels.12 Herken et al. reported no correlation between the severity of disease and SOD, ADA, XO, and NO parameters.5 In the present study we found a positive correlation between severity of disease and serum TOS and OSI; we also found a negative correlation between severity of disease and serum TAC. Bilici et al. reported that subchronic treatment with SSRI (fluoxetine, sertraline, fluvoxamine, citalopram) for 3 months reduced antioxidant enzyme activities (AEA) and malondialdehyde (MDA).12 Khanzode et al. showed an improvement in the oxidative stress parameters of MDD patients treated with SSRI (fluoxetine and citalopram).14 Herken et al. found an increase in the antioxidative system parameter SOD activity and oxidative system parameter ADA activity, while the NO level and XO levels decreased following 8 weeks of SSRI treatment in MDD patients.5 Sarandol et al.6 showed that antidepressants did not change TAC or oxidative (MDA, RBC susceptibility) or antioxidative (vitamin E, vitamin C, total carotenoid levels, SOD, GPx) system parameters following 6 weeks of treatment with various antidepressants (venlafaxine, reboxetine + sertraline, sertraline or reboxetine). In the present study, after 3 months of SSRI treatment (sertraline, paroxetine, escitalopram) serum TAC significantly increased and OSI and TOS significantly decreased. Among all these studies,6,12,14 only Sarandol et al. measured pre- and post-treatment serum TAC.6 In that study on MDD patients, the pre-treatment serum TAC was lower than in the control group, but this did not differ significantly from the MDD post-treatment level. In the present study the pre-treatment serum TAC was lower than in the control group, similar to the Sarandol et al. study,6 but it was higher in the post-treatment group than in the pre-treatment group, in contrast to that study. The increased TAC following 3 months of SSRI treatment in the present study, in contrast to the lack of change following 6 weeks of SSRI treatment in the Sarandol et al. study,6 indicates that the oxidative and antioxidative system may not change following antidepressant treatment for a short period of 6 weeks, and that long-term treatment such as 3 months, as in the Bilici et al. study,12 is needed for oxidative and antioxidative system parameters to change. Sarandol et al. found 60 of 96 patients to be responders on week 6 (62.5%) while 48 of the present 56 patients were responders (84.2%) in the same week. The mean


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Table 2. Pre- and post-treatment TAC and TOS vs response status (42 days)

TAC responder (n = 48) TAC non-responder (n = 9) TOS responder (n = 48) TOS non-responder (n = 9)

Before treatment After treatment Before treatment After treatment Before treatment After treatment Before treatment After treatment

Mean ⫾ SD

t, P

1.11 ⫾ 0.16 1.17 ⫾ 0.14 1.07 ⫾ 0.19 1.11 ⫾ 0.16 16.60 ⫾ 2.62 14.46 ⫾ 2.25 14.71 ⫾ 1.50 14.50 ⫾ 1.42

3.657 0.001 1.402 0.198 6.721 0.0001 1.109 0.300

TAC, total antioxidant capacity; TOS, total oxidant status.

MADRS score of the present patients at week 6 was 12.71 ⫾ 5.83, with all patients in remission at the end of the 3 months (MADRS ⱕ9). In the present study the TAC had a statistically significant increase in the 6-week responders while the TOS had a statistically significant decrease. Non-responders showed no significant change regarding these values. The increase in TAC and decrease in TOS when patients start to respond to treatment and the MADRS score decreases is an important finding indicating a relationship between disease severity and TAC–TOS. The Sarandol et al. study reported no change in serum TAC and various oxidative system parameters after 6 weeks of treatment.6 In addition they compared the pre-treatment values and percent changes of the parameters between the responders and nonresponders, and found no significant differences. The Sarandol et al. study was different to the present one in that they did not find a change in serum TAC and there was no significant change in serum TAC in the responder and non-responder groups with treatment.6 Some studies have reported a decrease in some oxidative system parameters (MDA, NO, XO) and an increase in some (SOD, ADA) with 8–12 weeks of treatment.5,12,14 Bilici et al. studied the antioxidative system parameter AEA and found a decrease following 3 months of treatment.12 These studies do not reflect TAC and TOS directly5,12,14 and it is not possible to compare them directly with the present study but the decrease in some oxidative stress parameters with treatment is similar to the present finding of serum TOS decrease. Responder and non-responder groups were not evaluated in these studies. The present significant results with responders and non-responders indicate that treatment duration may be important. We did not determine the menstrual cycle of female patients in the present study and did not

check whether the menstrual cycle affected TAC–TOS and this is a limitation of the study. Many studies have shown a disturbance in the oxidative and antioxidative status serum levels in disorders such as schizophrenia, dementia and depression.5–7,28–30 The ideal study would be to evaluate TAC and TOS in brain tissue or the cerebrospinal fluid but this is not practical. The various oxidative– antioxidative system parameters that were measured are substances that pass from the brain to the blood and vice versa and many studies have analyzed these parameters only in the serum, as in the present study. The important features of the present study are a uniform patient and control group with no other diagnosed psychiatric disorders and no history of smoking or addiction, the measurement of TAC and TOS and a long-term treatment schedule continuing for 3 months. In conclusion, we found higher serum TOS and lower serum TAC in MDD patients than in healthy volunteers. Treatment with antidepressants lowered TOS and raised TAC in the serum of MDD patients. One of the major findings of the present study was the significant increase in serum TAC, together with a significant decrease in TOS in responders on day 42 of treatment.

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