Impaired Homocysteine Metabolism Associated with High Plasma Interleukin-17A Levels, a Pro-Atherogenic Marker, in an Endogamous Population of North India.

Background: Impaired homocysteine metabolism (IHM; hyperhomocysteinemia) has been linked with many complex disorders like cardiovascular diseases and immunological disturbances. However, studies understanding IHM in light of pro- and anti- atherogeneic markers like Interleukin-17A & -10 (IL-17A & IL-10) and Forkhead box p3 (Foxp3, a master transcription factor) are scarce. Aim: In our present study, we aimed to understand the relation of IHM with plasma IL-17A and IL-10 levels and Foxp3 mRNA expression in peripheral blood mononuclear cells (PBMCs) from an endogamous population (Jats of Haryana, North India) with high prevalence of IHM without the concurrence of significant adverse cardiovascular outcomes. Methods: Forty (40) clinically healthy individuals, unrelated up to first cousins, were recruited and were subjected to demographic, physiological and anthropometric profiling, followed by intravenous blood sample collection (fasting) and lipid profiling. Plasma homocysteine levels were estimated and individuals with homocysteine levels ≥ 15umol/L and <15umol/L were categorized as the impaired homocysteine metabolism group (IHM, n=30) and normal homocysteine metabolism group (NHM, n=10) respectively. Plasma folate and vitamin B12 and MTHFR C677T (methylenetetrahydrofolate reductase) polymorphism were detected. Relative mRNA expression of Foxp3 in PBMCs (normalized to 18S) was quantitated using SyBR green technology. Plasma IL-10 & 17 levels were estimated by ELISA assays. Results and Conclusions: None of the physiological, anthropometric and lipid variables were different between the two groups. Foxp3 mRNA expression levels were relatively lower, and plasma IL-10 levels were found to be comparable among IHM and NHM group. However, significantly higher IL-17A levels and relatively high LDL cholesterol levels were present in the IHM group as compared with NHM. Our findings suggest that the Jats of Haryana, North India, exhibiting high levels of homocysteine, might also carry the high IL-17A -pro-atherogenic marker, suggesting an increasing burden of pre-morbid condition. This apparently does not reach to significant mortality/morbidity attributed to the counter action or balancing act of IL-10 (an anti-atherogenic marker). This further suggests environment-influenced epigenetic control mechanisms of the targeted genes in the present population.

Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism among Gaddi tribe of Indian state of Himachal Pradesh.

BACKGROUND: Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism has been suggested to be positively associated with several disorders. Distribution of the mutant T-allele varies in ethnic and geographical populations of the world. AIM: The aim of the present study was to investigate the distribution of methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism in a transhumant (Gaddi) tribal population of Himachal Pradesh dwelling at high and middle altitude and exposed to strong ultraviolet radiation. METHOD AND RESULTS: A total of 486 samples (141 males and 345 females) were randomly enrolled from the individuals aged 25-75 years who were unrelated up to first cousin. Among Gaddis, genotype frequencies of CC, CT and TT were 67.90%, 27.78% and 4.32%, respectively. Among males and females distribution of genotype frequencies also followed a similar trend. The studied population was in Hardy-Weinberg equilibrium (χ(2 )= 2.213, df = 1, p = 0.136). Frequency of mutant T-allele in the Gaddi population was found to be 0.183, which might be due to European ancestry, endogamous nature and selection.

MTHFR C677T polymorphism, folate, vitamin B12 and homocysteine in recurrent pregnancy losses: a case control study among North Indian women.

AIM: The present study attempts to understand the role of methylenetetrahydrofolate reductase C677T (MTHFR C677T) in recurrent pregnancy losses in North Indian women because of hyperhomocysteinemia in light of serum folate and vitamin B12. METHODS: One hundred and seven women with three or more consecutive unexplained recurrent pregnancy losses and 343 women with two or more successful and uncomplicated pregnancies were recruited. Plasma homocysteine, serum folate and vitamin B12 were analyzed using chemiluminescence. MTHFR C677T detection was completed in all subjects. RESULTS: MTHFR genotypic distribution among cases and controls showed no significant difference (P=0.409). However, MTHFR C677T polymorphism was found to be significantly associated with increased homocysteine in the case group (P=0.031). Hyperhomocysteinemia and vitamin B12 deficiency were found to be significant risk factors for recurrent pregnancy loss (RPL) (OR=7.02 and 16.39, respectively). Folate deficiency was more common in controls (63.47%) as compared to the case group (2.56%). CONCLUSION: Low vitamin B12 increases homocysteine, specifically among T allele carrying case mothers, suggesting T allele is detrimental with B12 deficiency. The study emphasizes the importance of vitamin B12 in the prevention of RPL in North Indian women.

DRD2 and ANKK1 gene polymorphisms and alcohol dependence: a case-control study among a Mendelian population of East Asian ancestry.

AIMS: Dopamine receptors are extensively studied in association with alcohol dependence (AD), since they are thought to be the key neural substrate for alcohol and other drug-related reinforcement and reward behaviours. The present study aims to understand the role of dopamine receptors in susceptibility to AD with respect to three sites of DRD2 gene (-141C Ins/Del, TaqIB and TaqID) and TaqIA site of ANKK1 gene among Meiteis of Manipur, a Mendelian population of India. METHODS: A total of 129 individuals who all met the DSM-IV criteria for AD and 286 controls were screened for four single-nucleotide polymorphisms (SNPs) -141C Ins/Del, TaqIB TaqID and TaqIA. Both AD cases and controls were unrelated up to first cousin. RESULTS: Early age of onset of alcohol consumption and smoking status were significantly associated with AD. Improvement in education and occupation statuses showed decreased risk of AD. The heterozygous and mutant homozygous conditions of ANKK1 TaqIA polymorphism were found to be significantly associated with AD (odds ratio = 2.13, 95% confidential interval 1.04-4.39, P < 0.05), whereas a borderline significance of the -141C Del allele was observed (P = 0.059). Such a trend was not observed between AD and the other polymorphism, i.e., TaqIB and TaqID. CONCLUSIONS: Individuals carrying the A1 allele of ANKK1 TaqIA polymorphism may be relatively more susceptible to AD. Interaction of both ANKK1 TaqIA and -141C Ins/Del polymorphism is likely to increase risk of AD phenotypes among Meiteis of Manipur, India.

Pro-inflammatory cytokine gene polymorphisms and threat for coronary heart disease in a North Indian Agrawal population.

The association of IFN-γ (+874 A/T; rs2430561), TNF-α (-308 G/A; rs1800629) and TNF-ß (+252 A/G; rs909253) with Coronary Heart Disease (CHD) has not been rigorously tested in Indian population. In the present study we sought to examine the role of these cytokines in the causation of CHD and their association with conventional CHD risk factors. A total of 138 case and 187 unrelated healthy controls aged 35 to 80years, matched on ethnicity and geography were collected from North Indian Agrawal population. Single nucleotide polymorphisms at the promoter TNF-α -308 G/A and the intronic IFN-γ +874 A/T were analyzed by allele-specific PCR, and the intronic TNF-ß +252 A/G was analyzed by RFLP. Of the three selected polymorphisms, genotypic distribution of IFN-γ +874 A/T and TNF-ß +252 A/G polymorphisms was significantly different between patients and controls in the present study. OR revealed statistically significant risk for CHD with respect to IFN-γ +874 T allele, whereas OR for TNF-ß +252 A/G showed three fold risk in homozygous condition though not significant. No such trend could be observed for TNF-α -308 G/A polymorphism. Multivariate logistic regression after adjusting for all the confounders showed significant risk for CHD with the genotypes and genotypic combinations of all the three markers (albeit not significant with TNF-α). Increased risk for CHD was likely to be associated with interaction of IFN-γ with diastolic hypertension, TNF-α with diabetes and BMI, and TNF-ß with serum triglyceride and very low density lipoprotein (VLDL) levels. The results suggest that these selected cytokine polymorphisms could possibly serve as potential bio-markers for CHD in conjunction with specific conventional risk factors.

Haptoglobin polymorphism among fourteen populations of India.

Haptoglobin (HP) is a serum protein that has the capability of binding the extracorpuscular haemoglobin released during haemolysis. It plays an important role in protection of haemolytic disease by reducing the oxidative and peroxidative potential at free haemoglobin. The present study was aimed to determine the prevalence of HP polymorphism among different Indian populations, anthropologically belonging to diverse ethnicity. The polymorphism was screened among 642 unrelated individuals belonging to 14 population groups of India including both tribal and non-tribal caste groups from different geographical regions of India with distinct linguistic affiliations. An attempt is also made to understand the distribution of HP polymorphism among the studied populations. The result reveals the HP gene to be polymorphic in all the studied populations. Except the two tribal populations (Thotis of Andhra Pradesh and Patelias of Rajasthan) and one caste population (Rajput of Himachal Pradesh), all the studied populations are found to obey the Hardy-Weinberg equilibrium. The significance of the present study is elucidated with the prevalence of high mutant HP*2 allele frequency in India. Selection could be one of the most plausible explanations for this high HP frequency because of its uniformly high occurrence among all the studied populations.

Spectrum of MTHFR gene SNPs C677T and A1298C: a study among 23 population groups of India.

Elevated homocysteine is a risk factor for many complex disorders. The role of methylenetetrahydrofolate reductase (MTHFR) gene in methylation of homocysteine makes it one of the most important candidate genes for these disorders. Considering the heterogeneity in its distribution in world populations, we screened MTHFR C677T and A1298C single nucleotide polymorphisms in a total of 23 Indian caste, tribal and religious population groups from five geographical regions of India and belonging to four major linguistic groups. The frequencies of MTHFR 677T and 1298C alleles were found to be 10.08 and 20.66%, respectively. MTHFR homozygous genotype 677TT was absent in eight population groups and homozygous 1298CC was absent in two population groups. 677T allele was found to be highest among north Indian populations with Indo-European tongue and 1298C was high among Dravidian-speaking tribes of east India and south India. The less common mutant haplotype 677T-1298C was observed among seven population groups and overall the frequency of this haplotype was 0.008, which is similar to that of African populations. cis configuration of 677T and 1298C was 0.94%. However, we could not find any individual with four mutant alleles which supports the earlier observation that presence of more than two mutant alleles may decrease the viability of foetus and possibly be a selective disadvantage in the population.

LDL-R AvaII and NcoI polymorphisms: an indirect risk factor for coronary heart disease among a Mendelian population of Delhi, India.

AvaII and NcoI polymorphisms in the low-density lipoprotein receptor (LDL-R) gene are reported to alter cholesterol levels. Although found to be highly polymorphic worldwide, these mutations have not been validated in any Indian population. This case-control association study was conducted in an endogamous business community of Delhi. Blood samples from 100 cases and 100 age- and sex-matched controls belonging to the same ethnic group were subjected to biochemical and molecular analyses. Medical history and anthropometric measurements were taken from all the enrolled subjects. Linkage disequilibrium between the two polymorphisms was found to be significant (P = 0.0016). Significant variability was observed for the AvaII polymorphism among cases concerning waist-hip ratio, serum triglyceride, and low-density lipoprotein, which in turn was found to be associated with coronary heart disease.

Genomic and linguistic affinities: a study of allelic and haplotype diversity at DRD2 locus among the tribes of Gujarat, western India.

Do genetic and linguistic affinities necessarily go hand in hand? An attempt has been made in the present work to explore this dimension of population structure using three evolutionarily important TaqI sites (TaqI A, TaqI B, and TaqI D) on the dopamine receptor D2 (DRD2) locus. For the first time, DNA samples from 612 unrelated individuals belonging to 11 Indo-European-speaking tribal population groups of Gujarat, western India, have been analyzed for these three sites. All the three sites are found to be polymorphic with greater interpopulation variation seen at the TaqI B site. The average heterozygosity for the haplotype system has been found to be high in the populations under study. Most of the populations share six of the eight haplotypes pointing toward underlying genetic uniformity, which is further reaffirmed by regression analysis of heterozygosity on genetic distance. The frequency of ancestral haplotype B2D2A1 is found to range between 1.9% and 15.9%. Linkage disequilibrium between TaqI B and TaqI D sites and between TaqI B and TaqI A sites is statistically significant in all but one population. Our findings reveal strong affinities between Indo-European-speaking tribal groups of Gujarat and Dravidian-speaking tribal groups of South India, suggesting that genetic affinities may not necessarily be dependent on linguistic similarities.

Brief communication: Allelic and haplotypic structure at the DRD2 locus among five North Indian caste populations.

The dopamine D2 receptor (DRD2) gene, with its known human-specific derived alleles that can facilitate haplotype reconstruction, presents an important locus for anthropological studies. The three sites (TaqIA, TaqIB, and TaqID) of the DRD2 gene are widely studied in various world populations. However, no work has been previously published on DRD2 gene polymorphisms among North Indian populations. Thus, the present study attempts to understand the genetic structure of North Indian upper caste populations using the allele and haplotype frequencies and distribution patterns of the three TaqI sites of the DRD2 gene. Two hundred forty-six blood samples were collected from five upper caste populations of Himachal Pradesh (Brahmin, Rajput and Jat) and Delhi (Aggarwal and Sindhi), and analysis was performed using standard protocols. All three sites were found to be polymorphic in all five of the studied populations. Uniform allele frequency distribution patterns, low heterozygosity values, the sharing of five common haplotypes, and the absence of two of the eight possible haplotypes observed in this study suggest a genetic proximity among the selected populations. The results also indicate a major genetic contribution from Eurasia to North Indian upper castes, apart from the common genetic unity of Indian populations. The study also demonstrates a greater genetic inflow among North Indian caste populations than is observed among South Indian caste and tribal populations.

MTHFR C677T and factor V Leiden in recurrent pregnancy loss: a study among an endogamous group in North India.

AIM: In our study an attempt has been made to find the prevalence of genetic thrombophilia in recurrent pregnancy loss (RPL). METHODS: Methylene tetrahydrofolate reductase C677 (MTHFR C677T) and factor V Leiden (FVL) were investigated in 84 Rajput women with two or more pregnancy losses and in 80 age- and ethnicity-matched healthy controls. Restriction digestions of polymerase chain reaction product with HinfI and Mnl I were used for MTHFR C677T and FVL polymorphism detection, respectively. RESULTS: MTHFR C677T mutation was found in 9/84 patients (10.71%) and 2/80 controls (2.5%), yielding an odds ratio (OR) for RPL related to MTHFR C677T of 4.68 (95% confidence interval [CI] = 0.98-22.37; p = 0.03). FVL was found in 4/84 patients (4.76%) and none among the controls, yielding a modified OR for RPL related to FVL of 9.00 (95% CI = 0.48-169.9; p = 0.05). Both, MTHFR C677T and FVL were not found to be significantly more prevalent in patients than controls as a whole. However, MTHFR C677T showed significant association with early pregnancy loss (OR = 6.3; 95% CI = 1.22-32.85; p-value = 0.03; Bonferroni-corrected p-value = 0.04). CONCLUSIONS: Our study supports the association between MTHFR C677T and patients with early RPL among north Indian Rajputs and strengthens the notion that thrombophilia plays a role in this clinical entity.

Emerging biomarkers: new directions and clinical applications.

This article summarizes content proceedings of a symposium held at the 2004 Research Society on Alcoholism Scientific Annual Meeting in Vancouver, Canada. The chairs were Friedrich M. Wurst and Raye Litten. The presentations were (1) Introduction, by Raye Litten; (2) Direct Ethanol Metabolites--On the Threshold From Science to Routine Use, by Friedrich M. Wurst; (3) Sialic Acid Index of Plasma Apolipoprotein J (SIJ) as a Viable Marker for Chronic Alcohol Consumption, by Philippe Marmillot; (4) The Emergence of Ethyl Glucuronide (EtG) Testing as a Tool in Monitoring Healthcare Professionals, by Gregory E. Skipper; (5) Application of Biomarkers for Alcohol Use Disorders in Clinical Practice, by Tim Neumann; (6) Utility of Biomarkers in Assessing the Efficacy of Medications for Treating Alcoholism, by Marty Javors; and (7) Discussion, by Raye Litten.

Regulatory enzymes of lipid metabolism in LA/N-cp rats.

Hepatic activities of rate limiting enzymes in fatty acid and cholesterol synthesis and cholesterol degradation were determined in lean and obese LA/N-cp rats. The hepatic activities of acetyl-CoA carboxylase and fatty acid synthetase, the key enzymes of fatty acid synthesis and 3-hydroxy-3-methylglutaryl coenzyme A reductase (the rate limiting enzyme in cholesterol synthesis), were increased 2-fold in the obese rats as compared with their lean littermates. In contrast, the activity of cholesterol 7alpha-hydroxylase, the rate limiting enzyme of cholesterol degradation to bile acids, was significantly decreased by 28% in the obese group as compared with the control group. Significantly, compared with the control group, the obese animals exhibited similar magnitudes of differences in the activities of the above enzymes even when they were pair-fed with the control animals. Thus these differences in the obese group are not due to hyperphagia but possibly to hypersecretion of the lipogenic hormone, insulin in this strain. These results indicate that the LA/N-cp obese rat has twice the capacity to synthesize body fat and cholesterol but has a reduced capacity to degrade the cholesterol, leading to increased accumulation of cholesterol and fat.