Serum trace elements, antioxidant-vitamins, immunoglobulins, lipid peroxidation, cortisol, amino acid level in patients with major depressive disorder and their correlation with disease status

Abstract

Background: Major Depressive Disorder (MDD) is a mental disorder characterized by a pervasive and persistent low mood which is accompanied by low self-esteem and loss of interest or pleasure in day to day activities that adversely affects a person's family, work and personal life. In Bangladesh 16.05% of adult population suffer from psychiatric illness of which 28.7% suffer from MDD. Currently this disease is diagnosed on the basis of patient's self-reported experiences, behavior reported by relatives or friends, and a mental status examination. There is no sufficient laboratory test for the diagnosis of MDD and it is expected that this investigation may be helpful for better diagnosis and management of MDD. Methods: Two hundred and forty seven patients with MDD were recruited from department of psychiatry, Bangabandhu Sheikh Mujib Medical University, Dhaka and 248 healthy volunteers were also recruited by matching with age, sex and socioeconomic status to the patient group with no previous history of any psychiatric disorders or any medical disease that may affect results. Analysis of the trace element has carried out by using flame atomic absorption spectroscopy using Varian SpectraAA 220. RP-HPLC was used for simultaneous determination of serum vitamin A and E concentrations. Concentration of vitamin C in serum was determined by spectrophotometric method. Serum concentrations of immunoglobulin A, G and M were determined by turbidimetry method using immunoglobulin kit. Modified method described by Satoh has been used to determine serum MDA. Serum cortisol level was measured by using ELISA kit. Serum levels of amino acids were measured by chromatographic methods (HPLC). Results: Our current study revealed that serum concentrations of Zn, Cu, Mn, Fe, Ca and Mg in MDD patients were 0.74±0.30, 0.86±0.41, 0.00056±0.00022, 1.24±0.30, 85.07±33.63 and 17.36±5.28 mg/L, while those were 1.01±0.19, 0.79±0.31, 0.00065±0.00032, 0.00132±0.00035, 104.33±11.13 and 21.24±3.03 mg/L in control subjects, respectively. Serum concentration of Zn, Mn, Ca and Mg decreased significantly in patient group (p<0.001, p=0.006, p<0.001 and p<0.001, respectively). But the differences of the concentration of Cu and Fe between patient and control group were not significant (p= 0.156 and p=0.056). Correlative analysis showed that serum Fe concentration has a significant correlation with age of patient (p=0.037). Serum Mg level has a direct correlation with Fe level (p=0.004) and Mg was inversely correlated with Cu (p<0.001) in the patient group. Serum levels of vitamin A, E and C were 2.05±1.16, 12.89±6.30 and 34.17±17.27 µmol/L in patients and the values were 2.33±0.92, 16.98±6.21 and 37.88±13.97 µmol/L for control subjects. Vitamin A, E and C levels decreased significantly in patients compared to the control subjects (p= 0.003, p<0.001 and p=0.009, respectively). Pearson’s correlation coefficient suggested that there was a significant positive correlation between vitamin A and E. Mean serum concentrations of IgA, IgG and IgM in patients were found to be 209.07±104.93, 791.50±235.67 and 107.92±47.53 mg/dL while those were 195.34±92.16, 763.81±175.89 and 99.17±48.78 mg/dL in control subjects, respectively. There were no significant difference of serum IgA, IgG and IgM between patients and control subjects (p=0.404, p=0.407 and p=0.293). Mean serum concentration of MDA was 5.16±2.56 µmol/L for patients and 3.21±1.77 µmol/L for control subjects. Significantly elevated level of serum MDA was found in MDD patients (p<0.001). Mean serum concentration of cortisol was 19.32±5.38 µg/dL in patients and 17.38±6.32 µg/dL for control subjects. Statistically significant elevated level of cortisol was found in patient group (p=0.024). Serum levels of most of the amino acids were decreased in MDD patients compare to control subjects whereas serum glycine level showed opposite result. Serum level of methionine, phenylalanine, tryptophan, and tyrosine were 18.35±9.80, 68.77±12.55, 51.60±12.57 and 54.78±21.99 µmol/L in patients while those were 22.48±8.72, 74.73±11.44, 59.73±11.44 and 60.23±28.58 µmol/L in control subjects. Serum concentration of methionine, phenylalanine, tryptophan, and tyrosine decreased significantly in patient group ( p<0.001, p=0.006, p<0.001, p<0.001 and p=0.018, respectively). Pearson’s correlation coefficient supports that serum level of methionine in patients has a significant positive correlation with phenylalanine and tryptophan. Smoking habit of patients has a significant positive correlation with serum methionine, phenylalanine and tryptophan level. Conclusion: Our result indicates that serum concentrations of most of the trace elements, amino acids and anti-oxidant vitamins were lower in patients compare to healthy control. But the elevated levels of serum MDA and cortisol were found in patients than control subjects. Difference in serum concentrations of IgA, IgG and IgM was not significant between the groups.