Association Between Serum Cystatin C and Creatinine in Chronic Kidney Disease Subjects Attending a Tertiary Health Care Centre.

INTRODUCTION: Chronic Kidney Disease (CKD) is an emerging health problem due to the increasing prevalence of conditions like diabetes mellitus and hypertension. Most patients are diagnosed during the later stages of CKD when the clinical symptoms become apparent. There is a need for early diagnosis to prevent disease progression and associated morbidities. Serum Creatinine (SCr) is commonly used among clinicians to determine renal function. However, SCr is affected by several factors and cannot be entirely relied upon. In pursuit of an alternative indicator of renal function, several biomarkers have been discovered and their utility in prompt diagnosis has been evaluated. Among such biomarkers, serum cystatin C (SCysC) has been extensively studied. AIM: To determine and compare the levels of SCr and SCysC in CKD subjects across various severity groups based on estimated Glomerular Filtration Rate (eGFR). MATERIALS AND METHODS: The study comprised of 120 CKD subjects. SCr was estimated by modified Jaffe's method and SCysC was estimated by particle enhanced immunoturbidimetric method. Estimated GFR (eGFR) was determined using Chronic Kidney Disease Epidemiology collaboration (CKD EPI) 2009 creatinine based formula. Based on eGFR, CKD subjects were further categorized into four groups. Statistical analysis was done using SPSS. Data were represented as median and interquartile range. Kruskal Wallis test was used for comparison between more than two groups. Correlation was done using Pearson's test. Statistical significance was considered as p <0.05. RESULTS: Both SCr and SCysC levels increased significantly across CKD groups (p<0.001). In CKD subjects with eGFR ≥ 60 ml/min/1.732 m2, the median value of SCr (1.01 mg/dl) was well within the normal range while median value of SCysC (1.34 mg/l) was found to be more than the upper reference limit. A positive correlation was present between SCysC and SCr (r=0.875, p<0.001). Both SCysC (r=-0.736) and SCr (r=-0.719) had a negative correlation with eGFR (p<0.001). CONCLUSION: SCysC is useful in detecting individuals with CKD having mild decrease in GFR compared to SCr. Both SCr and SCysC levels increase with decrease in eGFR. SCysC may be used to screen patients with poorly controlled diabetes mellitus or hypertension when SCr level is inconclusive.

Lipid peroxidation, hemolysis and antioxidant enzymes of erythrocytes in stroke.

Erythrocyte membrane lipid peroxidation and consequent percentage hemolysis and related antioxidant enzymes viz., superoxide dismutase, glutathione peroxidase, glutathione reductase and catalase were determined in 16 cases of hemorrhagic stroke and 30 cases of thrombotic stroke. The results obtained were compared with 50 age and sex matched controls. 12 thrombotic stroke patients who showed symptomatic recovery after medication were considered for follow up. Lipid peroxidation and percentage hemolysis in patients with thrombotic stroke and hemorrhagic stroke was significantly elevated when compared to controls. Glutathione reductase and superoxide dismutase levels were found to be significantly reduced in thrombotic stroke and hemorrhagic stroke respectively, when compared to healthy subjects. There was no significant difference in the other parameters when compared to controls. In post treatment thrombotic stoke, catalase and glutathione reductase levels increased significantly and oxidative hemolysis decreased compared to their pretreatment values. Thus, our results indicate considerable oxidative stress in stroke.

Oxidative stress and antioxidants in tubercular meningitis.

Oxidative stress is implicated in the etiopathogenesis of a variety of human diseases. Therefore, in the present study, erythrocyte lipid peroxidation, percentage hemolysis, antioxidant enzymes viz., glutathione reductase, glutathione peroxidase, superoxide dismutase and plasma antioxidants viz., ceruloplasmin, vitamins A,E and C have been determined in 19 patients with tubercular meningitis (TBM) and 50 normals. Six patients who were treated with antibiotics were considered for the follow up. The statistical analysis was carried out by Mann Whitney U test and Wilcoxon rank sum test. Lipid peroxidation (P<0.02), percentage hemolysis (P<0.001) and plasma ceruloplasmin (P<0.0001) of TBM patients were significantly higher, whereas erythrocyte glutathione reductase (P<0.05) and plasma antioxidant vitamins A, E and C (P<0.01, P<0.05 respectively) were significantly lower than those of the controls. In the follow up patients the glutathione reductase and catalase levels were significantly high (P<0.05) compared to their pre-treated condition. Vitamin C and E levels have attained normal range. This study indicated that the blood antioxidant status of TBM patients which was low compared to controls improved after treatment, suggesting the role of free radicals in TBM.