Effect of latent iron deficiency on GABA and glutamate neuroreceptors in rat brain

Eight weeks of latent iron deficiency in weaned female rats of Sprague Dawley strain maintained on experimental low-iron diet (18-20 mg/kg) did not significantly change the gross body, weight and tissue weights of brain and liver. Packed cell volume (PCV) and hemoglobin concentration remained unaltered. However, non-heme iron content in liver and brain decreased significantly (p<0.001). The activities of glutamate dehydrogenase, glutamic acid decarboxylase, and GABA-transaminase (GABA-T) in brain decreased by 15%, 11.4% and 25.7% respectively. However, this decrease was not statistically significant. Binding of(3)H Muscimol at pH 7.5 and 1 mg protein/assay increased by 143% (p<0.001) in synaptic vesicular membranes from iron-deficient rats as compared to the controls.(3)H glutamate binding to the synaptic vesicles was also carried out under similar condition. However, the L-glutamate binding was reduced by 63% in the vesicular membranes of iron deficient animals. These studies indicate that iron plays important functional role in both excitatory and inhibitory neurotransmitter receptors.

Effect of genetic variant (rs11887534) in ABCG8 gene in coronary artery disease and response to atorvastatin therapy

BACKGROUND

ATP-binding cassette transporter ABCG8 plays an important role in excretion of cholesterol from liver. Common genetic polymorphisms in ABCG8 gene may genetically predispose an individual to coronary artery disease (CAD) along with response to atorvastatin therapy. Thus, we aimed to examine the role of ABCG8 D19H polymorphism (rs11887534) in susceptibility to CAD and its influence on atorvastatin response.

METHODOLOGY

The study included 213 CAD patients and 220 controls. Genotyping of ABCG8 D19H polymorphism was done by PCR-RFLP.

RESULTS

Our results showed that ABCG8 'H' allele was conferring significant risk for CAD in a dominant model (OR=2.54; p=0.014). This increased risk for CAD was more pronounced in males (OR=2.69; p=0.030). No correlation of ABCG8 genotypes with the risk factors (diabetes, hypertension and smoking) of CAD was observed. On atorvastatin treatment there was a significant decrease in the LDL-C levels (p=0.021). However, stepwise multiple regression analysis showed that this decease was not associated with ABCG8 genetic variant (p=0.845). Observed determinants of variation in interindividual response to atorvastatin therapy were pre-treatment LDL-C (p= 0.024) and TC (p=0.017).

CONCLUSION

Although the genetic variant 19H of ABCG8 confers risk for CAD in North Indian population, it is not associated with interindividual response to atorvastatin therapy.

Association of Common Single Nucleotide Polymorphisms of Candidate Genes with Gallstone Disease: A Meta-Analysis

Numerous studies have investigated the relationship between various candidate gene polymorphisms and gallbladder stone disease (GSD) across ethnic populations; however, the results are often inconsistent. This meta-analysis aims to comprehensively evaluate the influence of common ABCG8 T400K, ABCG8 D19H, ABCG8 C54Y, ApoB100 EcoRI, ApoB100 XbaI, ApoE HhaI, CETP TaqI, CYP7A1 Bsa, LRPAP1 I/D and TNF-α A308G polymorphisms on the risk of gallbladder stone disease. 33 Full-text articles with 9250 cases and 12,029 healthy controls (total 21,279 subjects) were analyzed using the RevMan software (V5.1) and the Comprehensive Meta-analysis software (Version 2.0, BIOSTAT, Englewood, NJ) a Random-effects model was applied. Begg's funnel plots, Fail-safe number, Egger's regression intercept and Begg and Mazumdar rank correlation tests were performed for the potential publication bias and sensitivity analysis. The studies were also sub-grouped into European and non-European groups to find out role of ethnicity, if any, on GSD risk. Studies included in quantitative synthesis were ABCG8 T400K rs4148217 (cases/controls, n = 671/1416) (4 studies), ABCG8 D19H rs11887534 (n = 1633/2306) (8 studies), ABCG8 C54Y rs4148211 (n = 445/1194) (3 studies), ApoB100 EcoRI rs1042031 (n = 503/390) (4 studies), ApoB100 XbaI rs693 (n = 1214/1389) (9 studies), ApoE HhaI rs429358 (n = 1335/1482) (12 studies), CETP TaqI rs708272 (n = 1038/1025) (5 studies), CYP7A1 Bsa rs3808607 (n = 565/514) (3 studies), LRPAP1 I/D rs11267919 (n = 849/900) (3 studies), TNF-α A308G rs1800629 (n = 997/1413) (3 studies). The combined results displayed significant association of ABCG8 D19H (GC + CC) [OR with 95%CI = 2.2(1.7-2.8); p < 0.00001], ABCG8 Y54C (GA + GG) [OR with 95%CI = 0.65(0.5-0.9); p = 0.01]. APOB100 EcoRI (GG vs. AA) [OR with 95%CI = 0.51(0.3-0.9); p = 0.05], (GG vs. GA) [OR with 95%CI = 0.6(0.4-0.9); p = 0.04], (GA + AA) [OR with 95%CI = 0.6(0.4-0.9); p = 0.006]. APOB Xba I (X- vs. X+) [OR with 95%CI = 0.53(0.3-0.8); p = 0.006. APOE Hha I (E4/E4 vs. E3/E3) [OR with 95%CI = 3.5(1.1-14.9); p = 0.04] and LRPAP1 I/D (ID + II) [OR with 95%CI = 1.27(1.0-1.6); p = 0.03] with the GSD risk. It was found that ABCG D19H was significantly associated with GSD in both European and Non-European populations. While APOB XbaI and LRPAP1 I/D markers were associated with gallstone disease only in Non- European population. Additionally, APOE HhaI and APOB 100 ECoRI were found to be associated with GSD only in European population. The results of quantitative synthesis suggest that the ABCG8 D19H polymorphism was associated with the increased risk of GSD in both European and Non-European populations, APOE Hha I and LRPAP1 I/D polymorphisms were associated with the increased risk of GSD in European and Non-European population respectively. However, no association was found in ABCG8 T400K, CETP Taq1, CYP7A1 Bsa and TNF-A308G polymorphisms with Gallstone Disease.

Higher alleles of apolipoprotein B gene 3' VNTR: Risk for gallstone disease

Imbalance in cholesterol homeostasis may lead to gallstone disease. Apolipoprotein B is sole component of low-density lipoprotein and plays an important role in cholesterol metabolism. The present study was carried out to explore the association of APOB 3' VNTR, exon 26 XbaI and signal peptide insertion/ deletion polymorphisms with gallstone disease. 214 ultrasonographically proven gallstone patients and 322 healthy, age and sex matched controls were taken for the study. Genotyping was done using PCR followed by polyacrylamide gel electrophoresis for VNTR and insertion/ deletion analysis. For APOB XbaI polymorphism PCR product was digested with XbaI restriction enzyme, followed by agarose gel electrophoresis. All statistical analyses were done using SPSS v11.5. Higher repeat alleles of APOB 3' VNTR polymorphism were more frequent in gallstone patients than in controls. Alleles with more than 57 repeats were present only in patient group. Long (L) alleles with repeat higher than 49, were significantly higher (P=0.000; OR=3.705, 95% CI 2.577-5.326) and medium (M) alleles were lower (P=0.000; OR=0.406, 95% CI 0.304-0.542) in patients than in controls. To nullify the effect of gender, data was further stratified into male and female population. APOB 3' VNTR, L alleles were imposing risk and M alleles were protective in both male and female population. APOBXbaI and insertion/deletion polymorphisms were not found to be associated with the gallstone disease. Longer alleles of APOB 3' VNTR occur more frequently in gallstone patients, and may be an important risk factor for the development of gallstone disease. APOB XbaI and signal peptide insertion/deletion polymorphisms may not be contributing to the risk for gallstone disease.

Role of angiotensin II type I (AT1 A1166C) receptor polymorphism in susceptibility of left ventricular dysfunction

BACKGROUND

Left ventricular dysfunction (LVD) with subsequent congestive heart failure (CHF) constitutes the final common pathway for a host of cardiac disorders. The impaired LV function develops in response to an ischemic insult followed by a fall in cardiac output that leads to activation of renin-angiotensin-system (RAS). Angiotensin II type I receptor (AT1), which mediate the vasoconstrictive and salt-conserving actions of the RAS, represent interesting candidate genes for cardiovascular diseases. Therefore, we conducted an association study between single nucleotide polymorphism (SNP) in AT1 gene and LVD in CAD patients.

METHODS AND RESULTS

The present study recruited a total of 950 subjects including 720 angiography confirmed CAD patients and 230 healthy controls. Among 720 CAD patients, 229 with reduced left ventricle ejection fraction (LVEF≤45%) were categorized as LVD. The AT1 (A1166C, rs5186) polymorphism was determined by ARMS-PCR. Our results showed that the frequency of AT1 1166AC and CC genotypes were significantly higher in LVD patients in comparison to non-LVD (LVEF >45%) patients (p value = 0.003; OR = 1.81 and p value <0.001; OR = 4.33). Further analysis showed that AT1 A1166C polymorphism was significantly associated with LV end diastole (p-value = 0.031), end systole (p-value = 0.038) dimensions, and mean LVEF (p-value = 0.035). Moreover, on comparing the AT1 A1166C polymorphism in CAD patients with healthy controls, we did not find any association both at genotypic and allelic level (p value = 0.927; OR = 1.04 and p value = 0.219; OR = 0.83) respectively.

CONCLUSIONS

Our study suggests that AT1 A1166C polymorphism may play significant role in conferring genetic susceptibility of LVD.

Multi-analytic approach elucidates significant role of hormonal and hepatocanalicular transporter genetic variants in gallstone disease in North Indian population

OBJECTIVE

Cholesterol gallstone disease (CGD) is a multifactorial and multistep disease. Apart from female gender and increasing age being the documented non-modifiable risk factor for gallstones the pathobiological mechanisms underlying the phenotypic expression of CGD appear to be rather complex, and one or more variations in genes could play critical roles in the diverse pathways further progressing to cholesterol crystal formation. In the present study we performed genotyping score, Multifactor dimensionality reduction (MDR) and Classification and Regression Tree analysis (CART) to identify combinations of alleles among the hormonal, hepatocanalicular transporter and adipogenesis differentiation pathway genes in modifying the risk for CGD.

DESIGN

The present case-control study recruited total of 450 subjects, including 230 CGD patients and 220 controls. We analyzed common ESR1, ESR2, PGR, ADRB3, ADRA2A, ABCG8, SLCO1B1, PPARγ2, and SREBP2 gene polymorphisms to find out combinations of genetic variants contributing to CGD risk, using multi-analytical approaches (G-score, MDR, and CART).

RESULTS

Single locus analysis by logistic regression showed association of ESR1 IVS1-397C>T (rs2234693), IVS1-351A>G (rs9340799) PGR ins/del (rs1042838) ADRB3-190 T>C (rs4994) ABCG8 D19H (rs11887534), SLCO1B1 Exon4 C>A (rs11045819) and SREBP2 1784G>C (rs2228314) with CGD risk. However, the MDR and CART analysis revealed ESR1 IVS1-397C>T (rs2234693) ADRB3-190 T>C (rs4994) and ABCG8 D19H (rs11887534) polymorphisms as the best polymorphic signature for discriminating between cases and controls. The overall odds ratio for the applied multi-analytical approaches ranged from 4.33 to 10.05 showing an incremental risk for cholesterol crystal formation. In conclusion, our muti-analytical approach suggests that, ESR1, ADRB3, in addition to ABCG8 genetic variants confer significant risk for cholesterol gallstone disease.

Association of beta2-adrenergic receptor and insulin receptor substrate-1 polymorphisms with obesity in a Northern Indian population

BACKGROUND

Imbalance in hormonal levels, regulated by host genetic factors, are known to be a major cause of obesity. Therefore, we aimed to evaluate association of genetic polymorphisms of beta(2)-adrenergic receptor (beta(2)-AR) and insulin receptor substrate-1 (IRS-1) with hormonal levels in northern Indian obese.

METHODS

A total of 111 obese and 89 age matched non-obese subjects were studied after taking detailed clinical profile. Hormonal assays in serum/plasma for different hormones were done using IRMA and RIA kits. Genetic analysis of beta(2)-AR (-47 and -20, T to C) and IRS-1 (Arg972Gly) was done using PCR-RFLP.

STATISTICAL ANALYSIS

Statistical analysis was performed by SPSS (version 11.5) software. All continuous variables were expressed as mean +/- SD and tested by ANOVA test. Comparisons of categorical variables were assessed using X(2) tests or Fisher's exact test. P-value <0.05 was considered as significant.

RESULTS

Analysis showed that obese subjects had significantly higher value of blood pressure (systolic), WHR, leptin insulin and glucagon and lower value of GH. In beta(2)-AR (-47) T/C and IRS-1 Gly972Arg gene polymorphisms we did not found significant differences in genotype or allele frequencies. Moreover, none of the studied hormonal or metabolic parameters showed any association with the gene polymorphisms.

CONCLUSIONS

Study reveals no significant association of beta(2)-AR (-47 and -20, T to C) and IRS-1 Gly 972 Arg polymorphisms with obesity in northern Indians.

SMN1 dosage analysis in spinal muscular atrophy from India

BACKGROUND

Spinal muscular atrophy (SMA) represents the second most common fatal autosomal recessive disorder after cystic fibrosis. Due to the high carrier frequency, the burden of this genetic disorder is very heavy in developing countries like India. As there is no cure or effective treatment, genetic counseling becomes very important in disease management. SMN1 dosage analysis results can be utilized for identifying carriers before offering prenatal diagnosis in the context of genetic counseling.

METHODS

In the present study we analyzed the carrier status of parents and sibs of proven SMA patients. In addition, SMN1 copy number was determined in suspected SMA patients and parents of children with a clinical diagnosis of SMA.

RESULTS

Twenty nine DNA samples were analyzed by quantitative PCR to determine the number of SMN1 gene copies present, and 17 of these were found to have one SMN1 gene copy. The parents of confirmed SMA patients were found to be obligate carriers of the disease. Dosage analysis was useful in ruling out clinical suspicion of SMA in four patients. In a family with history of a deceased floppy infant and two abortions, both parents were found to be carriers of SMA and prenatal diagnosis could be offered in future pregnancies.

CONCLUSION

SMN1 copy number analysis is an important parameter for identification of couples at risk for having a child affected with SMA and reduces unwarranted prenatal diagnosis for SMA. The dosage analysis is also useful for the counseling of clinically suspected SMA with a negative diagnostic SMA test.

No direct association of serotonin transporter (STin2 VNTR) and receptor (HT 102T>C) gene variants in genetic susceptibility to migraine

We aimed to find out if the serotonin receptor (HT102T>C) and serotonin transporter (STin 2) polymorphisms play any role in genetic susceptibility of migraine. For the study, 217 migraine patients and 217 healthy controls (HC) were recruited and genotyping was carried out using the Polymerase Chain Reaction and Restriction Fragment Length polymorphism (PCR-RFLP) method. All results were Bonferroni corrected. We could not find any significant differences in the genotype or allele frequencies in case of HT 102 T>C polymorphism between migraine patients and healthy controls (P value=0.224). No significant association was seen at allele and carrier levels. Sub-grouping the patients on the basis of gender or on basis of migraine type i.e. with or without aura also did not show any association. Similarly, no difference in genotype (P value=0.236), allele (P value=0.550) or carrier frequency (P value=0.771) in STin 2 VNTR polymorphism was observed between migraine patients. However, HT 102 TC genotype was observed to interact significantly with the STin 2.10/10 genotype in enhancing risk of migraine, both with and without aura. In conclusion, the HT102 T>C receptor and the STin 2 VNTR transporter polymorphisms, did not individually confer any significant risk of migraine or its clinical subtypes but the two polymorphisms appear to synergistically influence susceptibility to migraine.

Possible role of CYP2C9 & CYP2C19 single nucleotide polymorphisms in drug refractory epilepsy

BACKGROUND & OBJECTIVES

Multiple drug resistance in epilepsy is a common problem and one third of epilepsy patients remain non responsive to antiepileptic drug (AED) therapy. In this study we aimed to investigate the relationship between the genetic polymorphism of cytochrome P450 genes, namely CYP2C9 and CYP2C19 with multiple drug resistance in epilepsy patients.

METHODS

A total of 402 patients with epilepsy were enrolled in this study; 128 were drug resistant and 274 were drug responsive. The peripheral blood samples of the patients with epilepsy were collected. Drug compliance was confirmed in 20 per cent patient population using HPLC. Genotyping of CYP2C9 (FNx012 and FNx013), and CYP2C19 (FNx012 andFNx013) was carried out by PCR-RFLP.

RESULTS

The genotype frequencies of CYP2C9 430 C>T (FNx012 variant) and CYP2C9 1075 A>C (FNx013 variant) did not differ significantly in drug resistant versus responsive patients. After combining CYP2C9 FNx012 and CYP2C9 FNx013, the frequency of CYP2C9FNx011/FNx013 was significantly lower in drug resistant as compared to drug responsive epilepsy patients (P=0.03, OR=0.53, 95%CI=0.30-0.95). Similarly, combined frequency of all the slow and poor metabolizer variants (2C9 FNx011/FNx012, FNx011/FNx013 and FNx012/FNx013) was also lower as compared to drug resistant group (P=0.03, OR=0.60, 95% CI 0.38-0.96). There was no significant differences in genotypic or allelic distribution of CYP2C190FNx012 while CYP2C19FNx013 was monomorphic in northern Indian population.

INTERPRETATION & CONCLUSIONS

Our results demonstrated significant involvement of CYP2C9 genetic variants in the modulation of epilepsy pharmacotherapy confirming the important role of CYP2C9 mutants preventing epilepsy patients from developing drug resistance.

CYP4F2 1347 G > A & GGCX 12970 C > G polymorphisms: frequency in north Indians & their effect on dosing of acenocoumarol oral anticoagulant

BACKGROUND & OBJECTIVES

CYP4F2 and γ-glutamyl carboxylase (GGCX) have small but significant roles in the maintenance dose of coumarinic oral anticoagulants (COAs). CYP4F2 1347 G > A and GGCX 12970 C > G polymorphisms have been used in the pharmacogenetic dosing algorithms of warfarin for Caucasians and Chinese populations. India has a large population with multiple ethnic groups but there are no reports about the frequencies of these polymorphisms in north Indians. In the present study, we aimed to find out the allelic frequencies of CYP4F2 1347 G > A and GGCX 12970 C > G polymorphisms in a north Indian population and relate these to daily maintenance drug dose requirements of COA.

METHODS

CYP4F2 1347 G > A and GGCX 12970 C > G polymorphisms were genotyped by polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) protocols and Taqman SNP discrimination assays in healthy volunteers (n=102) and patients (n=225) receiving acenocoumarol, an oral anticoagulant, after cardiac valve replacement surgery.

RESULTS

In healthy volunteers, the allele frequencies for CYP4F2 1347 G > A and GGCX 12970 C > G were 43.14 and 1.43 per cent, respectively. No significant differences in mean weight normalized doses of acenocoumarol were found for these CYP4F2 and GGCX genotypes. Binary logistic regression analysis revealed no significant association of any of the genotypes or alleles with the dosing phenotypes for both the SNPs.

INTERPRETATION & CONCLUSIONS

We report distinct frequencies of CYP4F2 1347 G > A and GGCX 12970 C > G polymorphisms in north Indians but these polymorphisms did not have significant bearing on maintenance dose of acenocoumarol oral anticoagulant in cardiac valve replacement patients.

Evaluation of microsatellite instability in tumors of central nervous system: A pilot study

Microsatellite instability (MSI) characterized by alterations at simple repetitive genomic sequences is a distinct mechanism in tumorogenesis. Central nervous system (CNS) tumors have been reported to exhibit MSI, indicator of defective mismatch repair system with controversies. The present study was undertaken to examine sixteen primary brain and two spinal tumors for MSI at six mono: BAT-26, BAT-40, BAX, TGFßRII, IGFIIR and hMSH3 and four dinucleotide loci: D2S123, D9S1851, D9S283 and D18S58. Polymerase chain reaction (PCR) was done to amplify tumour and blood DNA, analyzed on 8% denaturing Polyacrylamide gel followed by autoradiography. Out of 18 CNS tumors examined, 39% exhibited MSI at BAT-26, BAT-40, D9S1851, D9S283 and D18S58 in tumoral DNA. However, no alteration was observed at BAX, TGFßRII, IGFIIR, hMSH3 and D2S123 loci. Low incidence of MS1-high hypothesizes role of MSI in evolution of CNS tumors but not in cancer initiation or progression.