Protein bound hexose and protein bound hexosamine as diagnostic indicators in severe depression

 

 

Abstract               Background: Depressive illness is considered to be a psychoneuro-immunological disorder due to peripheral immune activation through the release of pro inflammatory cytokines. Cytokines enhance the hepatic synthesis of glycoproteins. Total glycoproteins are estimatied the protein bound hexose and protein bound hexosamine levels. Aim: To analyze whether protein bound hexose (PBH), protein bound hexosamine (PBHex) can be used as diagnostic indicator in severe depression. Material and Methods: The present study included 100 subjects which were grouped as Group I (Cases): included the patients who were diagnosed as having severe depression diagnosed on the basis of ICD –10 criteria. Group II (Controls): Healthy control subjects were selected from volunteers. Serum levels of protein bound hexose (PBH), protein bound hexosamine (PBHex) were estimated. Results: The mean level of Protein bound Hexose in severe depression was 191.054.01 mg% whereas it was 102.505.81 mg% (p value <0.0001). The mean level of Protein bound Hexosamine in severe depression was 97.505.06 mg% whereas it was 78.504.97 mg% (p value <0.0001). The mean levels of Protein bound Hexose and Protein bound Hexosamine in severe depression was significantly higher than controls. (p value <0.0001). Conclusion: The present study shows significantly increased levels of protein bound hexose and hexosamine in severe depressive patients. As serum glycoproteins are non-specific indicators of severe depression, they cannot be used as a diagnostic marker.

Key Word: Severe depression, protein bound hexose, protein bound hexosamine, diagnosis.

 

 

INTRODUCTION

Mood disorders encompass a large group of psychiatry disorders where psychomotor related vegetative disturbances dominate the clinical picture. Depressive illness is considered to be a psychoneuro-immunological disorder due to peripheral immune activation through the release of pro inflammatory cytokines. These cytokines are responsible for the behavioral, neuroendocrine, neurochemical alterations and modulation of hypothalamic-pituitary- adrenal axis.¹ Cytokines enhance the hepatic synthesis of glycoproteins.²Glycoproteins are organic compounds composed of protein and monosaccharide like hexose, hexosamine, fucose and sialic acid (N-acetyl neuraminic acid) connected covalently. Glycoproteins have multiple functions. Enzymes, hormones, blood group substances, constituents of cell membrane are found to be glycoproteins. The glycoproteins can be estimated and expressed in terms of the concentration of their constituent sugars. Many authors have determined the total glycoproteins by estimating the protein bound hexose and protein bound hexosamine.^3,4 In psychiatric disorders such as schizophrenia, elevated levels of serum glycoprotein have been reported.⁵ So, it was thought of interest to investigate the changes in the level of serum glycoprotein in patients of severe depression. Hence, the present study was undertaken to analyze whether protein bound hexose (PBH), protein bound hexosamine (PBHex) can be used as diagnostic indicator in severe depression.

 

MATERIAL AND METHODS

The present study included 100 subjects which were grouped as cases (n=50) and controls (n=50).

Group I (Cases): included the patients who were diagnosed as having severe depression by the clinical psychiatrist.

Group II (Controls): Healthy control subjects were selected from volunteers on the basis of good health as evidenced by the medical history, complete physical examination and routine laboratory tests performed prior to the commencement of the study.

The study was carried out after obtaining necessary approval from Institutional Ethical Committee and Informed consent obtained from the healthy control subjects and from the legal guardian of the patients.

Inclusion Criteria

• Patients with Severe Depression based on ICD–10 criteria.
• Patients aged 25-55 years
• Both sex

Exclusion Criteria

• Age <25 years
• Patients with history of cardiovascular disease, Pulmonary tuberculosis, trauma, prolonged bed rest, carcinoma cervix, breast, chronic alcoholism
• Patients with diabetes, hypertension

Severe depressive episode: (F32.2)

• General Criteria F32 must be met
• All three symptoms in criteria B, F32.0 must be present
• Additional symptoms from F32.0 Criteria C to give a total of at least 8.
• No Hallucinations, delusion or depressive stupor.

Estimation of Protein Bound Hexose and Hexosamine

• Protein Bound Hexose (PBH): Protein bound hexose was estimated by the method of Weimer HE and Moshin JR.⁶ In this method, the hexose moiety of glycoprotein conjugates precipitated by ethanol at room temperature. Then determined by orcinol reaction and read at 540nm.
• Protein bound hexosamine (PBHex): Protein bound hexosamine was estimated by the method of Winzler.⁷ In this method, serum proteins are precipitated by ethanol and hexosamines are liberated from the glycoproteins by acid hydrolysis. Acetylation in alkaline medium cyclizes the hexosamine to pyrrole derivative that couple with paradimethyl amino bezaldehyde forming color complex, which was determined photometrically at 530 nm.

Statistical analysis: Data were expressed as Mean ± Std. deviation. The data so obtained was analyzed to obtain appropriate conclusions. Student ‘t’ test was employed to find out the statistical significance.

 

RESULTS

The total number of subjects included for the study were 100. Out of these, 50 were cases (patients with severe Depression) and 50 were controls.

The patients and controls were grouped in to three according to the age. They were,

Group 1: 25-35 years

Group 2:36-45 years

Group 3: 46-55 years

Table 1: Comparison of Mean levels of serum Protein bound Hexose and Hexosamine in patients with severe depression and controls

The mean level of Protein bound Hexose in severe depression was 191.05±4.01 mg% whereas it was 102.50±5.81 mg% (p value <0.0001). The mean level of Protein bound Hexosamine in severe depression was 97.50±5.06 mg% whereas it was 78.50±4.97 mg% (p value <0.0001). Themean levels of Protein bound Hexose and Protein bound Hexosamine in severe depression was significantly higher than controls. (p value <0.0001). The mean levels of protein bound hexose and protein bound hexosamine were compared within the different age group taken for the study. No significance was found between the age groups for the protein bound hexose and protein bound hexosamine levels in serum either in the study group or in controls. The mean values are significantly higher in both the sex in patients with severe depression compared to controls. The comparison of Protein bound hexose and protein bound hexosamine within males and females do not show any significance. This infers that age and sex do not influence the parameters.

 

Table 2: Correlation between Protein bound Hexose and Protein bound Hexosamine in patients with severe depression and controls

Pearson’s correlation analysis was carried out to find the relationship between the parameters, Protein bound Hexose and Protein bound Hexosamine. There was a significant positive correlation between Protein bound Hexose and Protein bound Hexosamine in patients with severe depression and controls.

DISCUSSION

The study shows a statistically significant difference in the mean concentration of Protein bound Hexose and Protein bound Hexosamine between the controls and patients with severe depression. This study also demonstrates an elevated level of serum glycoproteins as Protein bound Hexose and Protein bound Hexosamine in severe depressed patients compared to the control group. The mean value of both the parameters in all 3-age groups was significantly higher in patients with severe depression than controls. The same was observed in both males and females of study subjects than controls. The mean values of parameters studied when compared among the age group and between males and females do not show any significance. This infers that the age and sex do not influence the levels of serum glycoproteins. Nandave et al⁴ reported changes in levels of serum glycoproteins in major depressive disorder. They have concluded that raised levels of glycoproteins may serve as an indicator of major depressive disorder. Elevated serum Glycoprotein levels represent a systemic response to non-specific stress. The levels are effected by pituitary adrenal axis. The change in the hypothalamic pituitary adrenal axis is caused by cytokines, which are the signaling molecules of the immune system.⁸ Seidel et al³ have reported significantly high levels of cytokines and serum proteins in patients with depression. An elevated cytokine levels indicate that depression is associated with exaggerated immune activity. The cytokines enhance the hepatic synthesis of acute phase proteins like alpha 1–acid Glycoprotein and other glycoproteins in patients with depression. Sluzeswka et al⁹ observed high level of serum alpha 1- acid Glycoprotein and C-reactive protein in patients with Major depressive disorder. The present study has found an increase in the levels of serum Protein bound Hexose and Protein bound Hexosamine in patients with severe depression. This is due to enhanced hepatic biosynthesis of glycoproteins mediated by cytokines. As there are many reports of increased glycoproteins in disorders of varied pathology, using the raised levels as a specific marker for depression is probably not useful to diagnose the condition. Glycoprotein increase due to raised cytokines is found in many unrelated disorders. Although the present study has observed significantly raised levels of protein bound hexose and hexosamine, they cannot be used as a diagnostic marker for severe depressive patients as the increase seems to be not specific for depression alone.

 

CONCLUSION

The present study shows significantly increased levels of protein bound hexose and hexosamine in severe depressive patients. As serum glycoproteins are non-specific indicators of severe depression, they cannot be used as a diagnostic marker. At best these levels may be used to study the response to treatment.

 

REFERENCES

1. Miller AH, Maletic V, Raison CL. Inflammation and Its Discontents: The Role of Cytokines in the Pathophysiology of Major Depression. Biological psychiatry. 2009;65(9):732-741.
2. Andus T, Bauer J, Gerok W. Effects of cytokines on the liver. Hepatology 1991;13(2):364-375.
3. Seidel A, Arolt V, Hunstiger M, Renk L, Behnisch A, Kirchner H. Cytokine production and serum proteins in depression. Scand J Immunol. 1995;41(6):534-538.
4. Nandave M, Ojha SK, Kaur R. Changes in levels of serum glycoproteins in major depressive disorders. Indian Journal of Clinical Biochemistry 2005;20(2):154-157.
5. Varma R, Hoshino AY. Serum glycoprotein in schizophrenia. Carbohydr. Res. 1980; 82: 343-351.
6. Weimer HE, Moshin JR. Comparative effects of intramuscular injections of ACTH, cortisone, and saline on serum glycoprotein levels. ProcSocExpBiol Med. 1953; 84:34-37.
7. Winzler RJ. Determinations of serum glycoproteins, Methods of biochemical analysis; Vol 2; Ed. Glick D.; 1955; pg. 279-311, Interscience Publishers, Newyork, USA.
8. Zunszain PA, Anacker C, Cattaneo A, Carvalho LA, Pariante CM. Glucocorticoids, cytokines and brain abnormalities in depression. Progress in Neuro-psychopharmacology and Biological Psychiatry. 2011;35(3):722-729.
9. Sluzewska A, Rybakowski JK, Sobieska M, Bosnians E, Pollet H, Wiktorowicz K. Increased levels of alpha‐1‐acid glycoprotein and interleukin‐6 in refractory depression. Depression 1995;3(4):170-175.