A Systematic Study of the Prevalence and Risk Factors of CKD in Uddanam, India.

INTRODUCTION: Despite reports of a high prevalence of chronic kidney disease (CKD) from the coastal Uddanam region of Andhra Pradesh, India, there are no accurate data on the distribution of kidney function abnormalities and CKD risk factors in this region. METHODS: A total of 2419 participants were recruited through multistage cluster random sampling from 67 villages. Serum creatinine and urine protein creatinine ratio were measured using validated methodologies. All abnormal estimated glomerular filtration rate (eGFR) and urine protein creatinine ratio values were reconfirmed after 3 months. A range of sociodemographic factors were evaluated for their association with CKD using Poisson regression. RESULTS: Of 2402 eligible subjects (mean ± SD age, 45.67 ± 13.29 years; 51% female), 506 (21.07%) had CKD (mean ± SD age, 51.79 ± 13.12 years; 41.3% female). A total of 246 (10.24%) had eGFR <60 ml/min/1.73 m2, whereas 371 (15.45%) had an elevated urine protein creatinine ratio (>0.15 g/g). The poststratified estimates, adjusted for age and sex distribution of the region for CKD prevalence, are 18.7% (range, 16.4%-21.0%) overall and 21.3% (range, 18.2%-24.4% ) and 16.2% (range, 13.7%-18.8%) in men and women, respectively. Older age, male sex, tobacco use, hypertension, and family history of CKD were independently associated with CKD. Compared with those with higher eGFR, those with eGFR <60 ml/min/1.73m2 were older, were more likely to be uneducated, manual laborers/farmers, or tobacco users, and were more likely to have hypertension, a family history of CKD, a diagnosis of heart disease, and a lower body mass index. Among those with low eGFR, there was no difference between those with urine protein creatinine ratio <0.15 or >0.15, except a lower frequency of males in the former. CONCLUSION: We confirmed the high prevalence of CKD in the adult population of Uddanam. The cause was not apparent in a majority. Subjects with a low eGFR with or without elevated proteinuria were phenotypically distinct from those with proteinuria and preserved eGFR. Our data suggest the need to apply a population-based approach to screening and prevention and studies to understand the causes of CKD in this region.

Association of NFKB1 gene polymorphism (rs28362491) with levels of inflammatory biomarkers and susceptibility to diabetic nephropathy in Asian Indians.

AIM: To investigate the association of NFKB1 gene -94 ATTG insertion/deletion (rs28362491) polymorphism with inflammatory markers and risk of diabetic nephropathy in Asian Indians. METHODS: A total of 300 subjects were recruited (100 each), normoglycemic, (NG); type 2 diabetes mellitus (T2DM) without any complications (DM) and T2DM with diabetic nephropathy [DM-chronic renal disease (CRD)]. Analysis was carried out by polymerase chain reaction-restriction fragment length polymorphism and ELISA. Pearson's correlation, analysis of variance and logistic regression were used for statistical analysis. RESULTS: The allelic frequencies of -94 ATTG insertion/deletion were 0.655/0.345 (NG), 0.62/0.38 (DM) and 0.775/0.225 (DM-CRD). The -94 ATTG ins allele was associated with significantly increased levels of urinary monocyte chemoattractant protein-1 (uMCP-1); uMCP-1 (P = 0.026) and plasma tumor necrosis factor-alpha (TNF-α); TNF-α (P = 0.030) and almost doubled the risk of diabetic nephropathy (OR = 1.91, 95%CI: 1.080-3.386, P = 0.025). CONCLUSION: -94 ATTG ins/ins polymorphism might be associated with increased risk of developing nephropathy in Asian Indian subjects with diabetes mellitus.

Association of tumor necrosis factor (TNF) promoter polymorphisms with plasma TNF-α levels and susceptibility to diabetic nephropathy in North Indian population.

AIM: The concept of diabetic nephropathy (DN) as a metabolic disease is now being replaced by chronic low-grade inflammatory disease. Tumor necrosis factor-alpha (TNF-α) is a proinflammatory cytokine which plays an important role in the pathogenesis and clinical outcome of DN. Therefore, this work was planned to evaluate the association of -863C/A (rs1800630) and -1031T/C (rs1799964) polymorphisms in TNF gene with plasma TNF-α levels and DN among subjects with type 2 diabetes (T2DM) in a population from North India. METHODS: Age and sex matched 100 healthy controls (HC), 100 T2DM subjects without nephropathy (DM) and 100 subjects with DN were screened for above polymorphisms using the PCR-RFLP methods. Plasma TNF-α levels were measured by ELISA. Analysis of variance and logistic regression were used to associate individual polymorphisms with plasma TNF-α levels and DN. RESULTS: The allelic frequencies of -863C/A were 0.86/0.14 in HC, 0.72/0.23 in DM and 0.84/0.16 in DN, and that of -1031T/C were 0.89/0.11 in HC, 0.95/0.05 in DM and 0.80/0.20 in DN. The carriers of -863A allele had significantly lower plasma TNF-α levels (p<0.05). The -863C/A (OR=0.439, 95% CI=0.244-0.789, p=0.006) and -1031T/C (OR=3.0, 95% CI=1.355-6.642, p=0.007) were strongly associated with risk of development of DN. CONCLUSIONS: -863C/A was associated with low whereas -1031T/C with high TNF-α levels. The, results suggest that -863C/A polymorphism might be protective whereas -1031T/C may be associated with increased risk for DN in subjects with T2DM from North India.

Increased level of organochlorine pesticides in chronic kidney disease patients of unknown etiology: role of GSTM1/GSTT1 polymorphism.

Chronic kidney disease (CKD) of unknown etiology represents about 16% of CKD patients in Indian subcontinents and 10% worldwide. The aetiology of CKD of unknown etiology remains unclear though epidemiological studies indicate the involvement of the environmental toxins. Organochlorine pesticides (OCPs) have been detected in general population in India. It is possible that polymorphism of xenobiotic metabolizing enzymes (XMEs) may play an important role in this process. In this we intend to find out blood levels of OCPs in CKD patients of unknown etiology and to evaluate the consequence of glutathione S-transferase (GST) gene polymorphism on the same. We have assessed 270 CKD patients and 270 age-sex-matched healthy controls for this study. The blood OCP levels were analyzed by gas chromatograph. GSTM1, GSTT1 genotyping were carried out by multiplex PCR. Blood levels of HCH, endosulfan and total pesticides were significantly higher in CKD patients and negatively correlated with eGFR. The combined frequency of GSTM1(-)/GSTT1(-) genotype increased the risk of CKD by 1.8-fold as compared to healthy controls. To find out the dependence of blood OCPs level on genotype, we carried out logistic regression analysis and results revealed that GSTM1(-)/GSTT1(-) genotype associated significantly with a number of OCPs namely γ-HCH, p,p'-DDT and total pesticides. Polymorphism of XMEs not only increased accumulation of pesticides but also aggravates kidney dysfunction as evident from significant decrease in eGFR.

The structural insights of stem cell factor receptor (c-Kit) interaction with tyrosine phosphatase-2 (Shp-2): an in silico analysis.

BACKGROUND: Stem cell factor (SCF) receptor c-Kit is recognized as a key signaling molecule, which transduces signals for the proliferation, differentiation and survival of stem cells. Binding of SCF to its receptor triggers transactivation, leading to the recruitment of kinases and phosphatases to the docking platforms of c-Kit catalytic domain. Tyrosine phosphatase-1 (Shp-1) deactivates/attenuates 'Kit' kinase activity. Whereas, Asp816Val mutation in the Kit activation loop transforms kinase domain to a constitutively activated state (switch off-to-on state), in a ligand-independent manner. This phenomenon completely abrogates negative regulation of Shp-1. To predict the possible molecular basis of interaction between c-Kit and Shp-1, we have performed an in silico protein-protein docking study between crystal structure of activated c-Kit (phosphorylated c-Kit) and full length crystal structure of Shp-2, a close structural counterpart of Shp-1. FINDINGS: Study revealed a stretch of conserved amino acids (Lys818 to Ser821) in the Kit activation domain, which makes decisive H-bonds with N-sh2 and phosphotyrosine binding pocket residues of the phosphatase. These H-bonds may impose an inhibitory steric hindrance to the catalytic domain of c-Kit, there by blocking further interaction of the activation loop molecules with incoming kinases. We have also predicted a phosphotyrosine binding pocket in SH2 domains of Shp-1, which is found to be predominantly closer to a catalytic groove like structure in c-Kit kinase domain. CONCLUSIONS: This study predicts that crucial hydrogen bonding between N-sh2 domain of Shp-1 and Kit activation loop can modulate the negative regulation of c-Kit kinase by Shp-1. Thus, this finding is expected to play a significant role in designing suitable gain-of-function c-Kit mutants for inducing conditional proliferation of hematopoietic stem cells.