P-selectin gene haplotype associations with albuminuria in the Diabetes Heart Study

Association of SELP Polymorphisms with Soluble P-Selectin Levels and Vascular Risk in Patients with Type 2 Diabetes Mellitus: A Case-Control Study

P-selectin, an adhesion molecule, is encoded by SELP and known as biomarker of endothelial as well as platelet dysfunction. SELP polymorphisms (rs6136, rs6127, and rs6125) and raised levels of soluble P-selectin (sP-selectin) have been associated with several disease conditions. The present study was aimed to determine the association of SELP variants and sP-selectin levels as well as vascular risk in Type 2 diabetes mellitus (T2DM) patients. The frequency of rs6136, rs6127, and rs6125 was assessed by restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR). sP-selectin levels were measured using commercially available kits. Haplotypes were constructed using PHASE software. The data obtained from the above-said analyses was subjected to suitable statistical analyses. sP-selectin levels (ng/ml) were significantly higher in patients as compared to controls (p < 0.001). Out of total, 22% of patients were found to have very high vascular risk, 43.2% with high vascular risk, while 34.4% with moderate vascular risk. For both rs6136 and rs6127, frequency of variant allele was found to be significantly higher in patients as compared to controls and accounted for 2.4- and 1.5-fold risk of disease development, respectively. CAG was found to be associated with 4.5-fold risk towards disease development. In contrast, AGG was conferring the protective effect. Significantly high sP-levels were observed in patients with homozygous wild genotype of rs6136, all genotypes of rs6127, and heterozygous genotype of rs6125 as compared to respective controls. Significant difference was observed in P-selectin levels within moderate-risk category for rs6136. When compared between the categories, significant difference was observed for rs6136 and rs6127. Furthermore, patients with haplotypes AAA, AGA, and AGG were found to have significantly high sP-selectin levels as compared to controls. Significant difference in sP-selectin levels was observed within very high-risk as well as high-risk category. When compared between the categories, significant difference was observed for AGA and AGG haplotypes. The studied polymorphisms of SELP have shown significant association with sP-selectin levels as well as vascular risk in T2DM patients.

Structural and functional impact of SNPs in P-selectin gene: A comprehensive in silico analysis

P-selectin is an adhesion molecule which plays an important role in the development of inflammation. It is encoded by the SELP gene located on chromosome 1q21-q24. Various single nucleotide polymorphisms (SNPs) ofSELPhave been reported to be associated with various inflammatory disease conditions. The genetics behind these diseases could be better understood by knowing the structural and functional impact of various genetic determinants ofSELP. So far, this is the first comprehensive and systematicin silicoanalysis of SNPs inSELP. A total of 2780 SNPs ofSELPwere retrieved from NCBI dbSNP. Only conserved and validated SNPs with minor allele frequency (MAF) ≥ 0.05 were subjected to further analysis. Based on these criteria, we selected 4 non-synonymous SNPs (nsSNPs) and 119 non-coding SNPs (ncSNPs). The nsSNPs were analyzed for deleterious effects using SIFT, Polyphen-2, nsSNPAnalyzer, SNP & Go, SNPs3, Mutperd and I-mutant web tools. The template prediction for variant structure modeling was performed using MUSTER and SWISS-MODEL. The functional impact of ncSNPs was analyzed by SNPinfo and RegulomeDB. Thein silicoanalysis predicted 3 nsSNPs and 21 ncSNPs as potential candidates for future case-control association studies and functional analysis ofSELP.

Effects of magnoline on P-selectin's expression in diabetic rats and its reno-protection

BACKGROUND AND OBJECTIVE

Magnoline is an active ingredient of magnolia fargesii with anti-inflammatory and anti-platelet effects. The objective is to explore the renoprotection of magnoline in diabetic rats and its effects on P-selectin.

METHODS

Thirty-six rats were randomized into 4 groups-normal control group (C), diabetic group (D), small-dose magnoline treatment group (M1) and large-dose magnoline treatment group (M2) (n=9 in each group). Streptozotocin was selected to construct diabetic rat model, and group M1 and group M2 were treated with magnoline 0.5mg/Kg.d and 2mg/Kg.d respectively. Urinary albumin excretion rate, renal function, levels of P-selectin and TGF-β1 were observed after 16 weeks.

RESULTS

Levels of albuminuria and serum creatinine of group M1 (1078.9 ± 77.3μg/24h, 29.7 ± 3.9μmol/L) and M2 (852.9 ± 80.1μg/24h, 30.9 ± 2.9μmol/L) were lower than group D (1572.8 ± 176.2μg/24h, 39.4 ± 4.1μmol/L) (P <0.05). Serum levels of P-selectin in group M1 and M2 were lower than group D (P <0.05). The renal expression of P-selectin and TGF-β1 in group M1 and M2 were significantly attenuated respectively.

CONCLUSIONS

Magnoline has reno-protective effects on diabetic rats which may be related to the inhibition of P-selectin.

Clinical significance of plasma CD146 and P-selectin in patients with type 2 diabetic nephropathy

OBJECTIVE

To investigate the levels of plasma CD146 and P-selectin in patients with type 2 diabetic nephropathy at different stages.

METHODS

A total of 80 patients with type 2 diabetes mellitus were enrolled in the present study. According to 24h urinary albumin excretion ratio and renal function, they were further divided into group of diabetes without microalbuminuria (DN0, n=20), microalbuminuria group (DN1, n=20), macroalbuminuria group (DN2, n=20) and renal insufficiency group (DN3, n=20). Another 20 healthy subjects were enrolled as control group (non-DM). Plasma CD146 and P-selectin were measured by ELISA.

RESULTS

Plasma CD146 and P-selectin were significantly increased in patients with type 2 diabetes with microalbuminuria (DN1) compared with health control (CD146: 415.3±29.0 vs. 243.5±14.7 ng/ml, P<0.05; P-selectin: 66.8±3.4 vs. 45.3±2.7 ng/ml, P<0.001). With the development of diabetic nephropathy, both plasma CD146 and P-selectin level progressively rise, with the highest levels in patients with significant renal insufficiency (DN3: 515.9±36.9 and 81.5±5.1 ng/ml respectively, P<0.001). Moreover, the increase in CD146 is positively co-related to the rise of P-selectin in patients with type 2 diabetes.

CONCLUSION

Expression of CD146 and P-selectin in patients with type 2 diabetes is elevated, and they are positively correlated with severity of diabetic nephropathy.

Candidate gene association study for diabetic retinopathy in persons with type 2 diabetes: the Candidate gene Association Resource (CARe)

PURPOSE

To investigate whether variants in cardiovascular candidate genes, some of which have been previously associated with type 2 diabetes (T2D), diabetic retinopathy (DR), and diabetic nephropathy (DN), are associated with DR in the Candidate gene Association Resource (CARe).

METHODS

Persons with T2D who were enrolled in the study (n = 2691) had fundus photography and genotyping of single nucleotide polymorphisms (SNPs) in 2000 candidate genes. Two case definitions were investigated: Early Treatment Diabetic Retinopathy Study (ETDRS) grades ≥ 14 and ≥ 30. The χ² analyses for each CARe cohort were combined by Cochran-Mantel-Haenszel (CMH) pooling of odds ratios (ORs) and corrected for multiple hypothesis testing. Logistic regression was performed with adjustment for other DR risk factors. Results from replication in independent cohorts were analyzed with CMH meta-analysis methods.

RESULTS

Among 39 genes previously associated with DR, DN, or T2D, three SNPs in P-selectin (SELP) were associated with DR. The strongest association was to rs6128 (OR = 0.43, P = 0.0001, after Bonferroni correction). These associations remained significant after adjustment for DR risk factors. Among other genes examined, several variants were associated with DR with significant P values, including rs6856425 tagging α-l-iduronidase (IDUA) (P = 2.1 × 10(-5), after Bonferroni correction). However, replication in independent cohorts did not reveal study-wide significant effects. The P values after replication were 0.55 and 0.10 for rs6128 and rs6856425, respectively.

CONCLUSIONS

Genes associated with DN, T2D, and vascular diseases do not appear to be consistently associated with DR. A few genetic variants associated with DR, particularly those in SELP and near IDUA, should be investigated in additional DR cohorts.

Review of the Diabetes Heart Study (DHS) family of studies: a comprehensively examined sample for genetic and epidemiological studies of type 2 diabetes and its complications

The Diabetes Heart Study (DHS) is a genetic and epidemiological study of 1,443 European American and African American participants from 564 families with multiple cases of type 2 diabetes. Initially, participants were comprehensively examined for measures of subclinical cardiovascular disease (CVD) including computed tomography measurement of vascular calcified plaque, ultrasound imaging of carotid artery wall thickness, and electrocardiographic intervals. Subsequent studies have investigated the relationship between bone mineral density and vascular calcification, measures of adiposity, and biomarkers. Ongoing studies are carrying out an extensive evaluation of cerebrovascular disease using magnetic resonance imaging and cognitive assessment. A second, parallel study, the African American DHS, has expanded the sample of African Americans to investigate marked racial differences in subclinical CVD between European Americans and African Americans. Studies in development will evaluate the impact of social stress during the lifecourse on CVD risk, and the prevalence of gastroparesis in this diabetes enriched sample. In addition, the ongoing high mortality rate in DHS participants provides novel insights into the increased risks for type 2 diabetes affected individuals. A comprehensive genetic analysis of the sample is underway using the genome-wide association study (GWAS) approach. Data from this GWAS survey will complement prior family-based linkage data in the analysis of genetic contributors to the wide range of traits in the sample. To our knowledge the DHS family of studies has created the most comprehensively examined sample of individuals with type 2 diabetes yet available, and represents a unique resource for the study people with type 2 diabetes. The aim of this review is to provide a collective overview of the major results from the DHS family of studies, and relate them to the larger body of biomedical investigations of diabetes and its complications.

[Volatile oil of Magnolia biondii inhibits expressions of P-selectin protein in serum and renal tissue of rats with diabetic nephropathy]

OBJECTIVE

To investigate the protection mechanism of volatile oil of Magnolia biondii Pamp. (VOMBP) against diabetic nephropathy in rats by observing its effects on level of soluble P-selectin (sP-selectin) in serum and expression of P-selectin in renal tissue.

METHODS

Fifty SD rats were randomly divided into normal control group, untreated group, and low-, medium- and high-dose VOMBP-treated group. Diabetic nephropathy was induced in rats by intraperitoneal injection of 1% streptozotocin. Before and the 1st day, 4th, 8th and 12th week after the induction, random blood glucose (RBG) and 24-hour urinary micro-albumin were detected in different groups. At the 12th week, the rats were sacrificed to collect the blood samples and renal tissues. The contents of blood urea nitrogen (BUN) and serum creatinine (SCr) were detected and the pathological change in renal tissues was observed by light microscope; the level of sP-selectin was detected by enzyme-linked immunosorbent assay and the expression of P-selectin protein in renal tissues was measured by immunohistochemical method.

RESULTS

Compared with the normal control group, RBG, 24-hour urinary micro-albumin, the contents of BUN, sP-selectin in serum and expression of P-selectin protein in renal tissue in the untreated group were significantly increased (P<0.01), the content of SCr was significantly decreased (P<0.01), and pathological change of renal tissues was also obvious. Compared with the untreated group, 24-hour urinary micro-albumin, the level of sP-selectin in serum and expression P-selectin protein in renal tissue of the three VOMBP-treated groups were all significantly decreased (P<0.01), and pathological change was lessened too. However, there were no significant differences among the three VOMBP-treated groups (P>0.05).

CONCLUSION

VOMBP can protect the kidney in rats with diabetic nephropathy by inhibiting the expressions of P-selectin protein in serum and in renal tissue.

Genetics of progressive renal failure in diabetic kidney disease

Diabetic kidney disease is a microvascular complication that is observed in a minority of patients with long-standing hyperglycemia. Diabetic nephropathy (DN) is associated with shortened patient survival, severe morbidity, and increased health care costs. Unfortunately, the incidence rates of DN continue to increase in Western societies, and DN is now the most common reported cause of end-stage renal disease in developed nations. DN results from a complex interplay between inherited and environmental factors. This article reviews the data that support an inherited basis for susceptibility to DN by summarizing familial aggregation studies, genome-wide linkage, and population-based association analyses in diabetic and nondiabetic kidney disease. Recent evidence linking genes involved in the regulation of endothelial function with genetic predisposition to albuminuria is presented. The integration of carefully designed genetic linkage and association studies with gene expression experiments in human and animal models of diabetic kidney disease appear to offer great promise for detecting the molecular mechanisms underlying susceptibility to DN.