Association of matrix metalloproteinase-2 gene variants with diabetic nephropathy risk.

BACKGROUND: Diabetic nephropathy is a highly destructive microvascular complication of diabetes. Genetic predisposition is involved in the pathogenesis of diabetic nephropathy, with multiple allelic polymorphisms associated with the development and progression of the disease, thereby increasing the overall risk. To date, no study is available that shows the association of matrix metalloproteinase-2 (MMP-2) gene polymorphisms with diabetic nephropathy risk. Thus, we investigated the potential genetic influence of MMP-2 promoter variants in the development of diabetic nephropathy in type 2 diabetic patients. METHODS: In total, 726 type 2 diabetic patients and 310 healthy controls were included in the study and genotyped for MMP-2, -1306C/T, -790T/G, -1575G/T and -735C/T by real-time PCR. The analysis of the outcomes was performed assuming three genetic models. The threshold for statistical significance was set at 0.05. RESULTS: The results showed that the minor allele frequency of the -790T/G variant was significantly higher in patients with and without nephropathy compared to controls. Furthermore, the distribution analysis revealed a significant association of the -790T/G variant, in all genetic models, with increased risk of diabetic nephropathy that persisted after adjusting for key covariates. No significant associations between MMP-2, -1306C/T, -1575G/T, -735C/T and the risk of diabetic nephropathy were detected. Haplotype analysis identified two risk haplotypes GCGC and GTAC associated with diabetic nephropathy. CONCLUSIONS: The present study is the first to demonstrate the allelic and genotypic association of the MMP-2-790T/G variant and two haplotypes with an increased risk of diabetic nephropathy in a Tunisian population with type 2 diabetes.

Association of MMP-2 genes variants with diabetic retinopathy in Tunisian population with type 2 diabetes.

AIMS: Few studies investigated the association of genetic difference in metalloproteinase-2 (MMP-2) gene with diabetic retinopathy but with mixed outcome. To investigate the association between a set of MMP-2 genetic variants and the risk of diabetic retinopathy in an Arab Tunisian population with type 2 diabetes. SUBJECTS AND METHODS: A retrospective case-control study comprising a total of 779 type 2 diabetes patients with or without diabetic retinopathy was conducted. Genotyping was prepared by TaqMan® SNP genotyping qRT-PCR. The variants used were rs243865 (C/T), rs243864 (T/G), rs243866 (G/T) and rs2285053 (C/T). RESULTS: The minor allele frequency (MAF) of the rs243864 MMP-2 variant was significantly higher among diabetic retinopathy patients. Setting homozygous wild type genotype carrier as reference, the rs243864T/G allele was associated with increased risk of diabetic retinopathy under the dominant, recessive, and additive models which persisted when key covariates were controlled for, while a reduced risk of diabetic retinopathy progression was seen after adjustment between non-proliferative and proliferative diabetic patients. Furthermore, the heterozygous genotype GT of the rs243866 variant is positively associated with the risk of proliferative diabetic retinopathy in the additive model. A limited linkage disequilibrium (LD) was revealed between the four-matrix metalloproteinase-2 variants. Four-loci haplotype analysis identified, GCTC, TTTC, and GCTT haplotypes to be positively associated with the risk of diabetic retinopathy. CONCLUSION: Our findings demonstrate that the MMP-2 variant rs243864 and 243866 are related to the susceptibility to diabetic retinopathy and the progression of the disease in an Arab Tunisian population with type 2 diabetes.

Association of matrix metalloproteinase-2 gene polymorphisms with susceptibility to type 2 diabetes: A case control study.

AIMS: Genetic variations mediating MMP-2 expression may result in individual differences in susceptibility to particular diseases. Our aim was to investigate the possible association of certain MMP-2 gene variants with the susceptibility of type 2 diabetes (T2D) in a Tunisian population. SUBJECTS AND METHODS: A retrospective case-control study involving 310 normoglycemic control subjects and 791 T2D patients was conducted. Genotyping of MMP-2 variants was performed by real time PCR. RESULTS: Minor allele frequencies (MAF) of the rs243865 and the rs243866 MMP-2, were significantly different between T2D cases and controls. Setting homozygous wild-type genotype carrier as reference, a reduced risk of T2D was seen with the rs243865 and the rs243866 genotypes. Haploview analysis revealed limited linkage disequilibrium between the tested MMP-2 and variants, with most haplotypes (99.5%) captured by 7 MMP-2 haplotypes. Taking the GCCC haplotype as reference for MMP-2 (OR = 1.00), a reduced frequency of TTCC haplotypes (P = 0.04) and the GTCC haplotype (P = 3.5 ·â€¯10-5) was noted in T2D which indicates a protective nature of these two haplotypes for T2D development. CONCLUSION: To the best of our knowledge, the present study is the first to demonstrate a consistent association of the rs243865 and rs243866 genotype with a protection for T2D.

Elevation in Circulating Soluble CD40 Ligand Concentrations in Type 2 Diabetic Retinopathy and Association with its Severity.

BACKGROUND: To investigate the relationship between changes in circulating soluble CD40 ligand (sCD40L) levels and the presence and severity of type 2 diabetic retinopathy (DR). SUBJECTS AND METHODS: sCD40L plasma concentrations were measured in 205 type 2 diabetes (T2DM) patients without DR (DWR; n=50) and with DR (n=155), the latter subdivided into non-proliferative diabetic retinopathy [NPDR; n=98 (63.2%)], or proliferative retinopathy [PDR; n=57 (36.8%)] patients. RESULTS: Receiver operating characteristic analysis provided good discriminatory power for sCD40L as predictor of DR presence, with high sensitivity and specificity. Categorizing DWR and DR patients into sCD40L quartiles, based on sCD40L concentrations in T2DM without DR, demonstrated statistically significant gradual increase in DR risk with increasing sCD40L levels. sCD40L levels were significantly higher in DR compared to DWR patients. Plasma sCD40L levels differed significantly according to DR severity, and correlated with diabetes duration, dyslipedimea, nephropathy, and presence of DR, but not with gender, age, SBP, DBP, FPG, HbA1c, T2DM medications. Linear regression analysis confirmed the association of increased sCD40L levels with DR, independent of others parameters; mean plasma sCD40L levels differing significantly according to DR severity. CONCLUSION: Plasma sCD40L levels were positively associated with DR. The significant finding here is that sCD40L levels can be predictors of DR severity.

Association of VEGFA variants with altered VEGF secretion and type 2 diabetes: A case-control study.

BACKGROUND: Vascular endothelial growth factor (VEGF) contributes to type 2 diabetes (T2DM) pathogenesis, and genetic variations in VEGFA gene were suggested to influence VEGF secretion and T2DM pathogenesis. AIM: To evaluate the association of specific VEGFA variants with altered VEGF levels, and with T2DM among Tunisians. SUBJECTS AND METHODS: A retrospective case-control study, performed on 815 T2DM patients, and 805 healthy controls. VEGF levels were measured by ELISA, genotyping of VEGFA variants was done by allelic exclusion method (real-time PCR). RESULTS: MAF of rs1570360, rs2010963, rs25648, rs833068, rs3025036, and rs3025039 were significantly different between T2DM cases and controls. Increased T2DM risk was associated with rs699947, rs1570360, and rs3025020, while reduced T2DM risk was seen with rs1547651, rs2010963, rs25648, rs3025036, and rs3025039 genotypes, thus assigning T2DM susceptibility and protection, respectively. Reduced VEGF levels were associated with rs833061, rs2010963, and rs3025039 heterozygosity and rs3025036 major allele homozygosity in T2DM cases, while increased VEGF levels were seen in rs833070 homozygous major allele genotype. Both rs699947 and rs1570360 positively, while rs2010963 and rs3025036 negatively correlated with fasting glucose. In addition, rs699947 positively correlated with LDL-cholesterol, and rs3025039 positively correlated with diabetes duration, but negatively with HbA1c and serum triglycerides. Haploview analysis identified Block 1 containing 8 loci, and Block 2 with the remaining 3 loci. Haplotypes ACTGCCGG and AACGGCGA (Block 1) were negatively associated with T2DM, while haplotype CCC was positively and haplotype CGC (Block 2) were negatively associated with T2DM. CONCLUSION: This study confirms the contribution of altered VEGF secretion, resulting from genetic variation in VEGFA gene into T2DM pathogenesis, hence supporting role for VEGFA as T2DM candidate locus.

Gender-dependent associations of CDKN2A/2B, KCNJ11, POLI, SLC30A8, and TCF7L2 variants with type 2 diabetes in (North African) Tunisian Arabs.

We investigated the impact of gender on T2DM association with confirmed susceptibility loci. CDKN2A/2B rs10811661, KCNJ11 rs5219, and TCF7L2 rs7903146 were associated with T2DM in females, while POLI rs488846 was associated with T2DM among males; the association of SLC30A8 rs13266634 and TCF7L2 rs4506565, rs12243326, and rs12255372 with T2DM was gender-independent.

Association of POL1, MALT1, MC4R, PHLPP and DSEL single nucleotide polymorphisms in chromosome 18q region with type 2 diabetes in Tunisians.

Previous studies and replication analyses have linked chromosome 18q21.1-23 with type 2 diabetes (T2DM) and its complications, including diabetic nephropathy (DN). Here we investigated the association of POL1-nearby variant rs488846, MALT1-nearby variant rs2874116, MC4R-nearby variant rs1942872, PHLPP rs9958800 and DSEL-nearby variant rs9966483 single nucleotide polymorphisms (SNPs) in the 18q region, previously linked with DN in African-Americans, with T2DM in (North African) Tunisian subjects, followed by their association with DN, which was performed subsequent to the analysis of the association with T2DM. Study subjects comprised 900 T2DM cases and 748 normoglycemic control, and genotyping was carried out by PCR-RFLP analysis. Of the 5 SNPs analyzed, POL1-nearby variant rs488846 [P=0.044], and MC4R-nearby variant rs1942872 [P=0.012] were associated with moderate risk of T2DM. However, there was a lack of consistency in the association of the 5 tested SNPs with DN. As such, it appears that the three chromosome 18q region variants appear to play a role in T2DM pathogenesis, but not with DN in North African Tunisian Arabs.

Transcription factor-7-like 2 gene variants are strongly associated with type 2 diabetes in Tunisian Arab subjects.

Genome-wide association studies validated transcription factor 7-like 2 (TCF7L2) gene as confirmed type 2 diabetes (T2DM) susceptibility locus, and an ethnic contribution of TCF7L2 variants to T2DM risk was indicated. The aim of this study was to replicate in a Tunisian Arab population identified associations of common TCF7L2 variants with T2DM. We tested the association of TCF7L2 variants: rs4506565, rs7903146, rs12243326, and rs12255372, with T2DM in 900 Tunisian patients and 875 control subjects. TCF7L2 genotyping was done by allelic discrimination/real-time PCR method. Minor allele frequencies of rs4506565 (P=2.4×10(-8)), rs7903146 (P=1.2×10(-6)), rs12243326 (P=8.4×10(-8)) and rs12255372 (P=1.1×10(-5)) were significantly higher in cases. The four tested TCF7L2 variants were in linkage disequilibrium, and 4-locus (rs4506565, rs7903146, rs12243326, rs12255372) haplotype analysis demonstrated that haplotype 1111 was negatively associated (Pc<0.001), while haplotypes 2222 (Pc=0.008) and 2211 (Pc=0.020) were positively associated with T2DM risk, after controlling for a number of covariates. The strong contribution of TCF7L2 gene variants to T2DM among Tunisians is in line with similar findings in other ethnic groups, confirming TCF7L2 as a common T2DM candidate gene.

Lack of association between genetic polymorphisms within KCNQ1 locus and type 2 diabetes in Tunisian Arabs.

AIMS: Polymorphisms of KCNQ1 were previously associated with type 2 diabetes (T2DM) in select Caucasian and non-Caucasian populations. We investigated the association of rs231361, rs231359, rs151290, rs2237892, rs2283228, rs2237895, and rs2237896 KCNQ1 polymorphisms with T2DM in Tunisian Arabs. SUBJECTS AND METHODS: Subjects comprised 900 T2DM patients and 600 normoglycemic controls. KCNQ1 genotyping was done by allelic discrimination (real-time PCR) and PCR-RFLP methods; the contribution of KCNQ1 polymorphisms to T2DM were analyzed by Haploview and regression analysis. RESULTS: Minor allele frequency (MAF) of the 7 tested KCNQ1 variants was comparable between T2DM cases and controls. Mild association of rs2237892 genotypes with T2DM was seen (P=0.014), highlighted by the significant association of the C/T genotype with increased T2DM risk (OR, 2.11; 95%CI, 1.25-3.53), after adjusting for BMI, gender, systolic and diastolic blood pressure, and serum lipid profile. Heterogeneity in linkage disequilibrium pattern between tested KCNQ1 variants analyzed was seen. Two-locus (rs231361 and rs231359) and 5-locus (remaining 5 SNPs) haplotype analysis did not reveal any significant association with any of the haplotypes contained in either block 1 or block 2. CONCLUSION: These results indicate that there was no evidence for an association of KCNQ1 polymorphisms with T2DM in Tunisian Arabs.

Transcription factor-7-like 2 gene variants are strongly associated with type 2 diabetes in Lebanese subjects.

We tested the association of TCF7L2 variants with type 2 diabetes (T2DM) in 691 Lebanese people and 919 controls. rs7901695, rs4506565, rs7903146, rs12243326, rs7895340, and rs12255372 minor allele frequencies were higher in T2DM. Haplotype analysis (rs7901695-rs4506565-rs7903146-rs12243326-rs7895340-rs11196205-rs12255372) identified positively- (2122112, 2222222) and negatively- (1111111) T2DM-associated haplotypes. TCF7L2 is a common T2DM candidate gene in Lebanese people.

Single-nucleotide polymorphisms and haplotypes in the adiponectin gene contribute to the genetic risk for type 2 diabetes in Tunisian Arabs.

Adiponectin is an adipocyte-produced protein involved in regulating glucose, lipid, and energy metabolism, and is encoded by ADIPOQ (APM1) gene. ADIPOQ polymorphisms were previously associated with type 2 diabetes (T2DM) in Caucasian and non-Caucasian populations. We investigated the contribution of 13 polymorphisms in the promoter, coding regions, and 3'untranslated region of ADIPOQ gene to T2DM in 917 patients and 748 normoglycemic control subjects. ADIPOQ genotyping was done by allelic discrimination method. Of the 13 ADIPOQ variants analyzed, higher minor allele frequency of rs16861194 (P<0.001), rs17300539 (P<0.001), rs266729 (P<0.001), rs822396 (P=0.02), rs2241767 (P=0.03), and rs1063538 (P=0.02) were seen in T2DM cases. Varied association of ADIPOQ genotypes with T2DM was seen according to the genetic model used: rs17300539 and rs266729 were significantly associated with T2DM under the three models, while rs16861194 was association with T2DM under additive and dominant models, and rs822396, rs2241766, and rs1063538 were associated with T2DM under the dominant models only. Haploview analysis revealed low linkage disequilibrium between the ADIPOQ variants, resulting in high haplotype diversity, and two blocks were identified, each differentially associated with T2DM. These results support a significant association of ADIPOQ gene polymorphism with T2DM in Tunisian Arabs.

Renin-angiotensin-aldosterone system genotypes and haplotypes affect the susceptibility to nephropathy in type 2 diabetes patients.

BACKGROUND: The association between renin C-4063T and angiotensinogen (AGT) T174M, M235T, and A-6G polymorphisms with diabetic nephropathy (DN) was investigated in Tunisian type 2 diabetes (T2DM) patients. METHODS: Study subjects comprised 917 T2DM patients (405 normoalbuminuric, 329 microalbuminuric and 185 macroalbuminuric). Genotyping was done by PCR-RFLP. RESULTS: Renin C-4063T allele and genotype frequencies were comparable between DN cases and normoalbuminuric controls. Although AGT 235T and -6G allele, and 235T/T and -6G/G genotype frequencies were higher in DN compared to normoalbuminuric patients, they were comparable between microalbuminuric or macroalbuminuric patients. Three-locus AGT haplotype analysis (A-6G/T174M/M235T) identified DN-protective (ATM, AMM, GTM) and DN-susceptible (GTM, ATT, GMT and AMT) haplotypes, and demonstrated enrichment of GTT haplotype in macroalbuminuric compared to microalbuminuric or normoalbuminuric patients. Regression analysis confirmed negative (AMM) and positive (GTM, ATT, GMT, AMT) association of AGT haplotypes with microalbuminuria, and negative (AMM) and positive (GTM and ATT) association of AGT haplotypes with macroalbuminuria. None of the AGT haplotypes was associated with DN severity. CONCLUSIONS: Genetic variation at the AGT gene influences the risk of nephropathy in T2DM patients but not extent of DN severity, and thus represents a potential DN genetic susceptibility locus worthy of replication.

Common polymorphisms of calpain-10 and the risk of Type 2 Diabetes in a Tunisian Arab population: a case-control study.

BACKGROUND: Genetic variations in the calpain-10 gene (CAPN10), in particular the at-risk diplotype (112/121), were previously implicated with increased risk of type 2 diabetes (T2D). METHODS: We examined the association of CAPN10 UCSNP-43 (rs3792267), UCSNP-19 (rs3842570), and UCSNP-63 (rs5030952) SNPs with T2D in 917 Tunisian T2D patients and 748 non-diabetic controls. CAPN10 genotyping was done by PCR-RFLP. RESULTS: Enrichment of UCSNP-19 2R (minor) allele and 2R/2R genotype was found in T2D patients; the allele and genotype distribution of UCSNP-43 and UCSNP-63 alleles and genotypes were not significantly different between patient groups and non-diabetic control subjects. Regression analysis demonstrated progressive increases in T2D risk in 3R/2R [OR (95% CI) = 1.35 (1.08 - 1.68)] and 2R/2R [OR (95% CI) = 1.61 (1.20 - 2.18)] genotypes. Of the six haplotypes detected, enrichment of haplotype 111 (UCSNP-43/UCSNP-19/UCSNP-63) was seen in patients (Pc = 0.034); the distribution of the other haplotypes was comparable between patients and control subjects; neither haplotype 211 nor haplotype 212 was observed. Furthermore, the frequency of all CAPN10 diplotypes identified, including the "high-risk diplotype (112/121) reported for Mexican-Americans and Northern Europeans, were comparable between patients and controls. CONCLUSIONS: CAPN10 UCSNP-19 variant, and the 111 haplotype contribute to the risk of T2D in Tunisian subjects; no significant associations between CAPN10 diplotypes and T2D were demonstrated for Tunisians.