Association of plasminogen activator inhibitor-1 4G/4G genotype and type 2 diabetic nephropathy in Chinese patients

Analysis and evaluation of correlation between DNA polymorphism in the genes MTHFR, PAI-1 and serum creatinine, creatinine clearance and albumin/creatinine ratio in morning urine of patients with type 2 diabetes mellitus and diabetic nephropathy

INTRODUCTION

Diabetic nephropathy is a major microangiopathic complication of type 2 diabetes and a leading cause of chronic kidney disease (CKD).

Serpin Family E Member 1 Tag Single-Nucleotide Polymorphisms in Patients with Diabetic Nephropathy: An Association Study and Meta-Analysis Using a Genetic Model-Free Approach

BACKGROUND

Many lines of evidence highlight the genetic contribution on the development of diabetic nephropathy (DN). One of the studied genes is SERPINE1 whose the role in the risk of developing DN remains questionable. In order to elucidate the contribution of SERPINE1 in DN progression in the context of type 2 diabetes mellitus (T2DM), we conducted an association study and meta-analysis of SERPINE1 genetic variants.

MATERIALS AND METHODS

A total of 190 patients with DN, 150 T2DM (type 2 diabetes mellitus) patients without DN and 238 healthy controls were recruited. We selected five tag single-nucleotide polymorphisms (SNPs) from the HapMap. The generalized odds ratio (ORG) was calculated to estimate the risk on DN development. Subgroup analyses based on ethnicity and type of diabetes were also performed.

RESULTS

Both the present association study regarding SERPINE1 SNPs (rs2227667, rs2070682, rs1050813, rs2227690, rs2227692) did not found any significant association between SERPINE1 variants and DN and the meta-analysis of variant 4G>5G (rs1799889) did not also reveal a significant association between 4G>5G variant and DN in main and subgroup analyses.

DISCUSSION

In conclusion, the present association study and meta-analysis provides strong evidence that SERPINE1 genetic variant 4G>5G is not implicated in the risk or development of DN in Caucasians. Further studies in other populations remain to further investigate the role of this variant in the course of DN.

The susceptibility of SERPINE1 rs1799889 SNP in diabetic vascular complications: a meta-analysis of fifty-one case-control studies

BACKGROUND

The serine protease inhibitor-1 (SERPINE1) rs1799889 single nucleotide polymorphism (SNP) has been constantly associated with diabetes mellitus (DM) and its vascular complications. The aim of this meta-analysis was to evaluate this association with combined evidences.

METHODS

The systematic search was performed for studies published up to March 2021 which assess the associations between SERPINE1 rs1799889 SNP and the risks of DM, diabetic retinopathy (DR), diabetic cardiovascular disease (CVD) and diabetic nephropathy (DN). Only case-control studies were identified, and the linkage between SERPINE1 rs1799889 polymorphism and diabetic vascular risks were evaluated using genetic models.

RESULTS

51 comparisons were enrolled. The results revealed a significant association with diabetes risk in overall population (allelic: OR = 1.34, 95 % CI = 1.14-1.57, homozygous: OR = 1.66, 95 % CI = 1.23-2.14, heterozygous: OR = 1.35, 95 % CI = 1.08-1.69, dominant: OR = 1.49, 95 % CI = 1.18-1.88, recessive: OR = 1.30, 95 % CI = 1.06-1.59) as well as in Asian descents (allelic: OR = 1.45, 95 % CI = 1.16-1.82, homozygous: OR = 1.88, 95 % CI = 1.29-2.75, heterozygous: OR = 1.47, 95 % CI = 1.08-2.00, dominant: OR = 1.64, 95 % CI = 1.21-2.24, recessive: OR = 1.46, 95 % CI = 1.09-1.96). A significant association was observed with DR risk (homozygous: OR = 1.25, 95 % CI = 1.01-1.56, recessive: OR = 1.20, 95 % CI = 1.01-1.43) for overall population, as for the European subgroup (homozygous: OR = 1.32, 95 % CI = 1.02-1.72, recessive: OR = 1.38, 95 % CI = 1.11-1.71). A significant association were shown with DN risk for overall population (allelic: OR = 1.48, 95 % CI = 1.15-1.90, homozygous: OR = 1.92, 95 % CI = 1.26-2.95, dominant: OR = 1.41, 95 % CI = 1.01-1.97, recessive: OR = 1.78, 95 % CI = 1.27-2.51) and for Asian subgroup (allelic: OR = 1.70, 95 % CI = 1.17-2.47, homozygous: OR = 2.46, 95 % CI = 1.30-4.66, recessive: OR = 2.24, 95 % CI = 1.40-3.59) after ethnicity stratification. No obvious association was implied with overall diabetic CVD risk in any genetic models, or after ethnicity stratification.

CONCLUSIONS

SERPINE1 rs1799889 4G polymorphism may outstand for serving as a genetic synergistic factor in overall DM and DN populations, positively for individuals with Asian descent. The association of SERPINE1 rs1799889 SNP and DR or diabetic CVD risks was not revealed.

Association of plasminogen activator inhibitor-1 4G5G Polymorphism with risk of diabetic nephropathy and retinopathy: a systematic review and meta-analysis

Background

The 4G5G polymorphism of Plasminogen activator inhibitor-1 (PAI-1) gene is reported to be associated with diabetes nephropathy and retinopathy (DNR) risk. However, the findings are conflicting. Herein, we conducted a case-control and meta-analysis study to explore the association of PAI-1 4G5G polymorphism with risk of DNR.

Methods

We retrieved PubMed, EMBASE, Web of Knowledge, and CNKI databases and screened eligible studies up to August 15, 2020. The strength of associations was assessed by odd ratio (OR) and the corresponding 95% confidence interval (95% CI).

Results

A total of 27 case-control studies including 16 studies with 1,825 cases case and 1,731 controls on DN and eleven studies with 1,397 cases and 1,545 controls on DR were selected. Pooled data showed that the PAI-1 4G5G polymorphism was significantly associated with DN (allele model: OR = 0.674, 95% CI 0.524-0.865, p = 0.002; homozygote model: OR = 0.536, 95% CI 0.351-0.817, p = 0.004; heterozygote model: OR = 0.621, 95% CI 0.427-0.903, p = 0.013; dominant model: OR = 0.575, 95% CI 0.399-0.831, p = 0.003; and recessive model: OR = 0.711, 95% CI 0.515-0.981, p = 0.038) and DR (homozygote model: OR = 0.770, 95% CI 0.621-0.955, p = 0.0.017) risk. Stratified analyses by ethnicity indicated that PAI-1 4G5G polymorphism was associated with DN and DR risk in Asians and Caucasians, respectively.

Conclusions

The present meta-analysis revealed that the PAI-1 4G5G polymorphism was associated with increased risk of DN and DR risk. However, well-designed large-scale clinical studies are required to further validate our results.

The -675 4G/5G PAI-1 polymorphism confers genetic susceptibility to systemic lupus erythematosus, its clinical manifestations, and comorbidities in Mexican-Mestizo population

Systemic lupus erythematosus (SLE) involves a broad range of factors that contribute to the development of the disease and its comorbidities. Genetic predisposition influences the development of SLE, and the -675 4G/5G PAI-1 polymorphism has been associated with several pathologies with a chronic inflammatory component. Our objective was to investigate the genetic association between the -675 4G/5G PAI-1 polymorphism with SLE, its clinical manifestations, and comorbidities in a Mexican-Mestizo population. The -675 PAI-1 polymorphism was determined by PCR-RFLP in 716 subjects: 293 SLE patients and 423 control subjects. Significant associations for SLE genetic susceptibility were found in carriers of 4G/5G (OR = 2.63; CI 1.81-3.87; p < .001) and 4G/4G (OR = 2.70; CI 1.62-4.51; p < .001) genotype in comparison with the 5G/5G genotype; 4G allele carriers also presented genetic risk for SLE (OR = 1.63; CI 1.31-2.03; p < .001) compared to the 5G allele. Following a dominant genetic model, a similar association was found with the 4G allele to SLE (OR = 2.66; CI1.84-3.84; p < .001). The 4G/5G genotype was associated with shorter disease duration (p = .039), as well as lower levels of haemoglobin (p = .001) and haematocrit (p = .009); the need for prednisone treatment (p = .001), higher BMI (p = .03), presence of type 2 DM (p = .015), clinical activity (Mex-SLEDAI = 57%; p = .047), Chronicity (SLICC-ACR = 0; p = .015) and CRP levels (p = .015) were associated with 5G/5G genotypes. In conclusion, the -675 4G/5G and 4G/4G PAI-1genotypes were found as genetic risk markers of susceptibility for SLE in the Mexican-Mestizo population, and each genotype could influence the clinical manifestations and comorbidities differently in SLE.

Association of PAI-1 4G/5G Polymorphism with Ischemic Stroke in Chinese Patients with Type 2 Diabetes Mellitus

BACKGROUND/AIM

To investigate the association of the genetic polymorphisms of the plasminogen activator inhibitor type 1 (PAI-1) gene with the risk of ischemic stroke (IS) in subjects with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

Using a case-control study design, 175 individuals with T2D and IS were enrolled in the case group and 125 patients with T2D without IS were enrolled as controls. The clinical characteristics of the groups were compared, and genotypes were determined by direct DNA sequencing.

RESULTS

Male and hypertensive subjects were higher in the IS group (p = 0.002 and 0.014, respectively). High-density lipoprotein (HDL) and apolipoprotein A1 (APOA1) were lower in the IS group (p = 0.011 and 0.025, respectively); hemoglobin A1c (HbA1c), total homocysteine (tHcy), and FT4 levels were higher in the IS group (p = 0.022, 0.003, and 0.008, respectively). The 4G/4G, 4G/5G, and 5G/5G genotype frequencies were 40.0%, 46.4%, and 13.6% in the control group versus 31.4%, 52.0% and 16.6% in the IS group, respectively. Hypertension (odds ratio [OR] = 1.953, p = 0.020), tHcy (OR = 1.059, p = 0.029), thyroid-stimulating hormone (OR = 0.876, p = 0.039), and the PAI-1 genotype dominant allele model (OR = 1.748, p = 0.047) were associated with IS by multivariate analysis.

CONCLUSION

The PAI-1 genotype dominant allele model was a risk factor for IS in patients with T2DM of Jinan, China.

Genetic variants in the plasminogen activator inhibitor-1 gene are associated with an increased risk of radiation pneumonitis in lung cancer patients

Plasminogen activator inhibitor‐1 (PAI‐1) plays a crucial role in the process of lung injury, although its association with radiation pneumonitis (RP) is unclear. We hypothesized that genetic variants in PAI‐1 may influence the risk of RP. In this study, 169 lung cancer patients were genotyped for six single‐nucleotide polymorphisms in PAI‐1 using the Sequenom MassARRAY system. The risk of RP was evaluated by Cox proportional hazards analyses. The cumulative RP probabilities by genotype were assessed using Kaplan–Meier analyses. Univariate and multivariate analyses revealed that PAI‐1:rs7242 GT/GG was correlated with an increased occurrence of grade ≥3 RP (crude hazard ratio = 3.331; 95% confidence interval, 1.168–9.497; P = 0.024). Our results indicated that PAI‐1:rs7242 in the 3′‐untranslated region of PAI‐1 can be a predictor of grade ≥3 RP before radiotherapy.

Role of ACE and PAI-1 Polymorphisms in the Development and Progression of Diabetic Retinopathy

In the present study we determined the association of angiotensin converting enzyme (ACE) and plasminogen activator inhibitor-1 (PAI-1) gene polymorphisms with diabetic retinopathy (DR) and its sub-clinical classes in Pakistani type 2 diabetic patients. A total of 353 diabetic subjects including 160 DR and 193 diabetic non retinopathy (DNR) as well as 198 healthy controls were genotyped by allele specific polymerase chain reaction (PCR) for ACE Insertion/Deletion (ID) polymorphism, rs4646994 in intron 16 and PAI-1 4G/5G (deletion/insertion) polymorphism, rs1799768 in promoter region of the gene. To statistically assess the genotype-phenotype association, multivariate logistic regression analysis was applied to the genotype data of DR, DNR and control individuals as well as the subtypes of DR. The ACE genotype ID was found to be significantly associated with DR (p = 0.009, odds ratio (OR) 1.870 [95% confidence interval (CI) = 1.04-3.36]) and its sub-clinical class non-proliferative DR (NPDR) (p = 0.006, OR 2.250 [95% CI = 1.098-4.620]), while PAI polymorphism did not show any association with DR in the current cohort. In conclusion in Pakistani population the ACE ID polymorphism was observed to be significantly associated with DR and NPDR, but not with the severe form of the disease i.e. proliferative DR (PDR).

Inhibition of Thrombin-Activated Fibrinolysis Inhibitor Increases Survival in Experimental Kidney Fibrosis

Uncontrolled diabetes, inflammation, and hypertension are key contributors to progressive renal fibrosis and subsequent loss of renal function. Reduced fibrinolysis appears to be a feature of ESRD, but its contribution to the fibrotic program has not been extensively studied. Here, we show that in patients with CKD, the activity levels of serum thrombin-activated fibrinolysis inhibitor and plasmin strongly correlated with the degree of renal function impairment. We made similar observations in rats after subtotal nephrectomy and tested whether pharmacologic inhibition of thrombin-activated fibrinolysis inhibitor with UK-396082 could reduce renal fibrosis and improve renal function. Compared with untreated animals, UK-396082-treated animals had reduced glomerular and tubulointerstitial fibrosis after subtotal nephrectomy. Renal function, as measured by an increase in creatinine clearance, was maintained and the rate of increase in proteinuria was reduced in UK-396082-treated animals. Furthermore, cumulative survival improved from 16% to 80% with inhibition of thrombin-activated fibrinolysis inhibitor. Taken together, these data support the importance of the fibrinolytic axis in regulating renal fibrosis and point to a potentially important therapeutic role for suppression of thrombin-activated fibrinolysis inhibitor activity.

PAI-1 -675 4G/5G polymorphism in association with diabetes and diabetic complications susceptibility: a meta-analysis study

A meta-analysis was performed to assess the association between the PAI-1 -675 4G/5G polymorphism and susceptibility to diabetes mellitus (DM), diabetic nephropathy (DN), diabetic retinopathy (DR) and diabetic coronary artery disease (CAD). A literature-based search was conducted to identify all relevant studies. The fixed or random effect pooled measure was calculated mainly at the allele level to determine heterogeneity bias among studies. Further stratified analyses and sensitivity analyses were also performed. Publication bias was examined by the modified Begg’s and Egger’s test. Twenty published articles with twenty-seven outcomes were included in the meta-analysis: 6 studies with a total of 1,333 cases and 3,011 controls were analyzed for the PAI-1 -675 4G/5G polymorphism with diabetes risk, 7 studies with 1,060 cases and 1,139 controls for DN risk, 10 studies with 1,327 cases and 1,557 controls for DR and 4 studies with 610 cases and 1,042 controls for diabetic CAD risk respectively. Using allelic comparison (4G vs. 5G), the PAI-1 -675 4G/5G polymorphism was observed to have no significant association with diabetes (REM OR 1.07, 95% CI 0.96, 1.20), DN (REM OR 1.10, 95% CI 0.98, 1.25), DR (REM OR 1.09, 95% CI 0.97, 1.22) or diabetic CAD risk (REM OR 1.07, 95% CI 0.81, 1.42), and similar results were obtained in the dominant, recessive and co-dominant models. Our meta-analyses suggest that the PAI-1 -675 4G/5G polymorphism might not be a risk factor for DM, DN, DR or diabetic CAD risk in the populations investigated. This conclusion warrants confirmation by further studies.

Plasminogen activator inhibitor-1 4G/5G polymorphism and retinopathy risk in type 2 diabetes: a meta-analysis

BACKGROUND

Mounting evidence has suggested that plasminogen activator inhibitor-1 (PAI-1) is a candidate for increased risk of diabetic retinopathy. Studies have reported that insertion/deletion polymorphism in the PAI-1 gene may influence the risk of this disease. To comprehensively address this issue, we performed a meta-analysis to evaluate the association of PAI-1 4G/5G polymorphism with diabetic retinopathy in type 2 diabetes.

METHODS

Data were retrieved in a systematic manner and analyzed using Review Manager and STATA Statistical Software. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations.

RESULTS

Nine studies with 1, 217 cases and 1, 459 controls were included. Allelic and genotypic comparisons between cases and controls were evaluated. Overall analysis suggests a marginal association of the 4G/5G polymorphism with diabetic retinopathy (for 4G versus 5G: OR 1.13, 95%CI 1.01 to 1.26; for 4G/4G versus 5G/5G: OR 1.30, 95%CI 1.04 to 1.64; for 4G/4G versus 5G/5G + 4G/5G: OR 1.26, 95%CI 1.05 to 1.52). In subgroup analysis by ethnicity, we found an association among the Caucasian population (for 4G versus 5G: OR 1.14, 95% CI 1.00 to 1.30; for 4G/4G versus 5G/5G: OR 1.33, 95%CI 1.02 to 1.74; for 4G/4G versus 5G/5G + 4G/5G: OR 1.41, 95%CI 1.13 to 1.77). When stratified by the average duration of diabetes, patients with diabetes histories longer than 10 years have an elevated susceptibility to diabetic retinopathy than those with shorter histories (for 4G/4G versus 5G/5G: OR 1.47, 95%CI 1.08 to 2.00). We also detected a higher risk in hospital-based studies (for 4G/4G versus 5G/5G+4G/5G: OR 1.27, 95%CI 1.02 to 1.57).

CONCLUSIONS

The present meta-analysis suggested that 4G/5G polymorphism in the PAI-1 gene potentially increased the risk of diabetic retinopathy in type 2 diabetes and showed a discrepancy in different ethnicities. A higher susceptibility in patients with longer duration of diabetes (more than 10 years) indicated a gene-environment interaction in determining the risk of diabetic retinopathy.

Plasminogen activator inhibitor-1 gene polymorphism in Iranian Azeri Turkish patients with FMF disease and its association with amyloidosis

Familial Mediterranean fever (FMF) is an autosomal recessive disorder characterized by intermittent episodes of fever with serositis, arthritis, or eriseplemya. Plasminogen activator inhibitor 1 (PAI-1) is a key element in the inhibition of fibrinolysis by inactivating tissue-type and urokinase-type plasminogen activators. We evaluated the association of PAI-1 -675 4G/5G polymorphism with the severity of FMF disease. For this purpose, 89 FMF patients with M694V homozygous mutation and 95 healthy controls from Iranian Azeri Turks were selected. Detection of this polymorphism was performed by polymerase chain reaction using allele-specific primers. No significant association was found between patients and control group. However, these data showed that FMF patients with M694V homozygous mutation carrying 4G/4G genotype have a reduced risk for development of pleuritis (odds ratios (OR) 0.36; 95 % confidence intervals (CI) 0.5-0.85; P value = 0.007) compared with 5G/5G homozygotes who have increased risk for development of amyloidosis (OR = 2.46; 95 %CI = 1.29-4.72; P value = 0.001), pleuritis (OR = 2.55; 95 %CI = 1.31-4.99; P value = 0.001), and fever (OR = 4.68; 95 %CI = 2.04-10.96; P value = 0.000). Furthermore, the allelic frequency of the 4G among the patients with pleuritis was significantly low (OR = 0.5, 95 % CI = 0.27-0.92, P value = 0.008).

CONCLUSION

Our data suggest a protective role for the 4G allele against pleuritis in FMF patients with M694V homozygous mutation in this cohort. More evaluation of this polymorphism may be important and require further studies.

Plasma plasminogen activator inhibitor-1 is associated with end-stage proliferative diabetic retinopathy in the Northern Chinese Han population

Objective. To identify predictors of end-stage proliferative diabetic retinopathy (PDR) in a cohort of individuals with type 2 diabetes mellitus (T2DM) from the Northern Chinese Han population. Methods. We investigated characteristics of 153 consecutive diabetic patients with end-stage PDR (62 males, 91 females), 123 consecutive PDR patients without end-stage PDR (48 males, 75 females), and 151 normal subjects (63 males, 88 females). Only one eye of each patient or healthy subject was included in this study. Univariate logistic regression models and multivariate logistic regression models were constructed to evaluate the predictors of end-stage PDR. Results. In univariate analysis, systolic blood pressure, diastolic blood pressure, duration of diabetes, family history of T2DM, and plasminogen activator inhibitor-1 (PAI-1) were significently associated with end-stage PDR. After multivariate analysis, family history of T2DM, plasma PAI-1 levels, smoking, and duration of diabetes were four positive predictors associated with end-stage PDR. Conclusions. Higher plasma levels of PAI-1 were associated with end-stage PDR in the Northern Chinese Han population with T2DM.

Tumor Necrosis Factor-α Gene Polymorphism Correlates with Cardiovascular Disease in Patients with End-Stage Renal Disease

BACKGROUND AND OBJECTIVE

Tumor necrosis factor-alpha (TNFalpha) is a potent proinflammatory cytokine. Through its effects on lipid metabolism and endothelial function, TNFalpha is involved in cardiovascular disease (CVD). We have studied two polymorphisms in the promoter region of the TNFalpha gene (TNF -308G/A and TNF -238G/A) in end-stage renal disease (ESRD) patients with and without CVD. The aim was to assess the association of these polymorphisms with ESRD and cardiovascular comorbidity in hemodialyzed patients.

METHODS

A total of 603 patients with ESRD treated with hemodialysis (382 patients with CVD) and 325 healthy control subjects were genotyped for the TNF -308G/A and TNF -238G/A ploymorphisms by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) procedure.

RESULTS

The A allele of the TNF -308 polymorphism was more frequent in the ESRD group than in control individuals. The odds ratio (OR) for the risk allele was 2.05 (95% CI 1.48, 2.84). In the subgroup of ESRD patients with CVD, the OR was 5.76 (95% CI 3.67, 9.03) relative to ESRD patients without CVD. There was no association observed between the TNF -238 polymorphism and renal failure or CVD in ESRD patients.

CONCLUSION

Our results demonstrate for the first time that the A allele of the TNF -308 polymorphism is associated with CVD in hemodialyzed ESRD patients. If confirmed in prospective studies, it may be a predictor of increased susceptibility to CVD in these patients.

Effect of plasminogen activator inhibitor-1 and tissue plasminogen activator polymorphisms on susceptibility to type 2 diabetes in Malaysian subjects

Elevated activity of plasminogen activator inhibitor-1 (PAI-1) and decreased tissue plasminogen activator (tPA) activity are considered to be important risk factors for type 2 diabetes mellitus (T2DM) and metabolic syndrome (MetS). The aim of this study was to investigate the association of the PAI-1 4G/5G and tPA Alu-repeat I/D polymorphisms with T2DM in Malaysian subjects. Serum insulin, coronary risk panel, plasma glucose, and PAI-1 4G/5G and tPA Alu-repeat I/D polymorphisms were studied in 303 T2DM subjects (227 with MetS and 76 without MetS) and 131 normal subjects without diabetes and MetS. Statistical analysis showed that the dominant and additive models of PAI-1 4G/5G polymorphism showed a weak association with T2DM without MetS (OR = 2.35, P = 0.045; OR = 1.67, P = 0.058). On the other hand, the recessive model of the tPA Alu-repeat I/D polymorphism showed an association with T2DM with MetS (OR = 3.32, P = 0.013) whereas the dominant and additive models of the tPA Alu-repeat I/D polymorphism were not associated with T2DM either with or without MetS.

Impact of the -675 4G/5G polymorphism of the plasminogen activator inhibitor-1 gene on childhood IgA nephropathy

Plasminogen activator inhibitor-1 (PAI-1) is an important regulator of the fibrinolytic pathway and extracellular matrix (ECM) turnover. The -675 4G/5G polymorphism in the PAI-1 promoter is associated with altered PAI-1 transcription, suggesting that this polymorphism may be a candidate risk factor for diseases characterized by ECM accumulation, such as immunoglobulin A nephropathy (IgAN) and mesangial proliferative glomerulonephritis (MesPGN). We genotyped childhood patients with biopsy-confirmed IgAN (n=111) and MesPGN (n=47), and healthy control subjects (n=230) for the -675 4G/5G PAI-1 polymorphism by polymerase chain reaction-restriction fragment length polymorphism methods. The distribution of the 4G/4G (27.9%), 4G/5G (45.1%) and 5G/5G (27.0%) genotypes in IgAN patients was significantly different from the healthy controls (32.2, 54.3 and 13.5%, respectively) (p=0.0092). There was no significant difference in the genotype distributions of the 4G/5G polymorphism between MesPGN patients and the healthy controls. Regarding the impact of the polymorphism on IgAN, the 4G/4G genotype was markedly increased in patients with proteinuria (≥1,000 mg/day) and/or hypertension when compared to patients without proteinuria and hypertension (OR=5.23, 95% CI 1.34-20.38, P=0.0183). These findings indicate that the PAI-1 gene polymorphism may affect the susceptibility of childhood IgAN.

PAI-1 mRNA expression and plasma level in rheumatoid arthritis: relationship with 4G/5G PAI-1 polymorphism

Rheumatoid arthritis (RA) is a chronic inflammatory disease affecting the synovial membrane, cartilage and bone. PAI-1 is a key regulator of the fibrinolytic system through which plasminogen is converted to plasmin. The plasmin activates the matrix metalloproteinase system, which is closely related with the joint damage and bone destruction in RA. The aim of this study was to investigate the relationship between 4G/5G PAI-1 polymorphism with mRNA expression and PAI-1 plasma protein levels in RA patients. 113 RA patients and 123 healthy subjects (HS) were included in the study. The 4G/5G PAI-1 polymorphism was determined by polymerase chain reaction-restriction fragment length polymorphism method; the PAI-1 mRNA expression was determined by real-time PCR; and the soluble PAI-1 (sPAI-1) levels were quantified using an ELISA kit. No significant differences in the genotype and allele frequencies of 4G/5G PAI-1 polymorphism were found between RA patients and HS. However, the 5G/5G genotype was the most frequent in both studied groups: RA (42%) and HS (44%). PAI-1 mRNA expression was slightly increased (0.67 fold) in RA patients with respect to HS (P = 0.0001). In addition, in RA patients, the 4G/4G genotype carriers showed increased PAI-1 mRNA expression (3.82 fold) versus 4G/5G and 5G/5G genotypes (P = 0.0001), whereas the sPAI-1 plasma levels did not show significant differences. Our results indicate that the 4G/5G PAI-1 polymorphism is not a marker of susceptibility in the Western Mexico. However, the 4G/4G genotype is associated with high PAI-1 mRNA expression but not with the sPAI-1 levels in RA patients.

Association analysis of ADPRT1, AKR1B1, RAGE, GFPT2 and PAI-1 gene polymorphisms with chronic renal insufficiency among Asian Indians with type-2 diabetes

BACKGROUND

To determine association of nine single nucleotide polymorphisms (SNPs) in ADP ribosyltransferase-1 (ADPRT1), aldo-keto reductase family 1 member B1 (AKR1B1), receptor for advanced glycation end-products (RAGE), glutamine:fructose-6-phosphate amidotransferase-2 (GFPT2), and plasminogen activator inhibitor-1 (PAI-1) genes with chronic renal insufficiency (CRI) among Asian Indians with type 2 diabetes; and to identify epistatic interactionss between genes from the present study and those from renin-angiotensin-aldosterone system (RAAS), and chemokine-cytokine, dopaminergic and oxidative stress pathways (previously investigated using the same sample set).

METHODS

Type 2 diabetes subjects with CRI (serum creatinine > or =3.0 mg/dl) constituted the cases (n = 196), and ethnicity and age matched individuals with diabetes for a duration of > or = 10 years, normal renal functions and normoalbuminuria recruited as controls (n = 225). Allelic and genotypic constitution of 10 polymorphisms (SNPs) from five genes namely--ADPRT1, AKR1B1, RAGE, GFPT2 and PAI-1 with diabetic CRI was investigated. The genetic associations were evaluated by computation of odds ratio and 95% confidence interval. Multiple logistic regression analysis was carried out to correlate various clinical parameters with genotypes, and to study epistatic interactions between SNPs in different genes.

RESULTS

Single nucleotide polymorphisms -429 T>C in RAGE and rs7725 C>T SNP in 3' UTR in GFPT2 gene showed a trend towards association with diabetic CRI. Investigation using miRBase statistical tool revealed that rs7725 in GFPT2 was a perfect target for predicted miRNA (hsa miR-378) suggesting the presence of the variant 'T' allele may result in an upregulation of GFPT2 contributing to diabetic renal complication. Epistatic interaction between SNPs in transforming growth factor TGF-beta1 (investigated using the same sample set and reported elsewhere) and GFPT2 genotype was observed.

CONCLUSIONS

Association of SNPs in RAGE and GFPT2 suggest that the genes involved in modulation of oxidative pathway could be major contributor to diabetic chronic renal insufficiency. In addition, GFPT2 mediated overproduction of TGF-beta1 leading to endothelial expansion and thereby CRI seems likely, suggested by our observation of a significant interaction between GFPT2 with TGF-beta1 genes. Further, identification of predicted miRNA targets spanning the associated SNP in GFPT2 implicates the rs7725 SNP in transcriptional regulation of the gene, and suggests GFPT2 could be a relevant target for pharmacological intervention. Larger replication studies are needed to confirm these observations.

The role of plasminogen activator inhibitor 1 in renal and cardiovascular diseases

The 50 kDa glycoprotein plasminogen activator inhibitor 1 (PAI-1) is the major physiological inhibitor of tissue-type and urokinase-type plasminogen activator. These two molecules convert inactive plasminogen into its fibrin-degrading form, plasmin. Plasma and tissue concentrations of PAI-1 are extremely low under normal circumstances but increase under pathologic conditions. This increase is mediated by many factors, including reactive oxygen species. Increased PAI-1 activity is associated with an increased risk of ischemic cardiovascular events and tissue fibrosis. Whereas the antifibrinolytic property of PAI-1 derives mainly from its inhibition of serine proteases, its profibrotic actions seem to derive from a capacity to stimulate interstitial macrophage recruitment and increase transcription of profibrotic genes, as well as from inhibition of serine proteases. Despite studies in mice that lack or overexpress PAI-1, the biological effects of this molecule in humans remain incompletely understood because of the complexity of the PAI-1-plasminogen-activator-plasmin system. The cardioprotective and renoprotective properties of some currently available drugs might be attributable in part to inhibition of PAI-1. The development of an orally active, high-affinity PAI-1 inhibitor will provide a potentially important pharmacological tool for further investigation of the role of PAI-1 and might offer a novel therapeutic strategy in renal and cardiovascular diseases.

Transcription factors in the pathogenesis of diabetic nephropathy

Approximately a third of patients with diabetes develop diabetic kidney disease, and diabetes is the leading cause of end-stage renal disease in most developed countries. Hyperglycaemia is known to activate genes that ultimately lead to extracellular matrix accumulation, the hallmark of diabetic nephropathy. Several transcription factors have been implicated in glucose-mediated expression of genes involved in diabetic nephropathy. This review focuses on the transcription factors upstream stimulatory factors 1 and 2 (USF1 and 2), activator protein 1 (AP-1), nuclear factor (NF)-kappaB, cAMP-response-element-binding protein (CREB), nuclear factor of activated T cells (NFAT), and stimulating protein 1 (Sp1). In response to high glucose, several of these transcription factors regulate the gene encoding the profibrotic cytokine transforming growth factor beta, as well as genes for a range of other proteins implicated in inflammation and extracellular matrix turnover, including thrombospondin 1, the chemokine CCL2, osteopontin, fibronectin, decorin, plasminogen activator inhibitor 1 and aldose reductase. Identifying the molecular mechanisms by which diabetic nephropathy occurs has important clinical implications as therapies can then be tailored to target those at risk. Strategies to specifically target transcription factor activation and function may be employed to halt the progression of diabetic nephropathy.

Lack of association between the angiotensin-converting enzyme gene (I/D) polymorphism and diabetic nephropathy in Tunisian type 2 diabetic patients

Objective. The aim of the present study was to investigate whether the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism is associated with diabetic nephropathy and type 2 diabetes in the Tunisian population.

Design. A case-control study was conducted among 141 unrelated type 2 diabetic patients with (90 patients) or without nephropathy (51 patients) and 103 non-diabetic controls with normal fasting blood glucose. Genotyping was performed using a nested polymerase chain reaction amplification in order to identify correctly heterozygous individuals.

Results. The distribution of DD, ID and II genotypes did not significantly differ between type 2 diabetic patients with or without nephropathy (DD: 44%; ID: 46%; II: 10% vs. DD: 41%; ID: 47 %; II: 12%, respectively).There was also no significant statistical difference between the genotype distribution and allele frequencies of the (I/D) polymorphism in all type 2 diabetic subjects compared to non-diabetic controls with normal fasting blood glucose (DD: 43%; ID: 46%; II: 11% vs. DD: 37%; ID: 48% ;II: 15%, respectively).

Conclusions. In the present preliminary study, the (I/D) polymorphis within the ACE gene is likely not associated with diabetic nephropathy nor with type 2 diabetes in the Tunisian studied population.

Common polymorphisms of the PAI1 gene do not play a major role in the development of diabetic nephropathy in Type 1 diabetes

AIM

Plasminogen activator inhibitor 1 (PAI1) plays a key role in the regulation of extracellular matrix (ECM) degradation. ThePAI1 gene is therefore an excellent candidate gene for diabetic nephropathy. The aim of this study was to employ gene resequencing to identify common DNA polymorphisms in thePAI1gene, and subsequently assess haplotype tagged single nucleotide polymorphisms(htSNPs) using a case control design. METHODS All nine exons, exon-intron boundaries, introns 1, 4 and 7 and approximately 3 kb upstream and 5 kb downstream of thePAI1 gene were screened for DNA polymorphisms in 15 case and 15 control subjects using WAVE denaturing high-performance liquid chromatography technology and confirmed by DNA sequencing. Polymorphisms were genotyped in 86 healthy individuals using direct sequencing and haplotype tagged single nucleotide polymorphisms (htSNPs) identified. Genotyping of the htSNPs was performed in 583 Type 1 diabetic patients (222 with nephropathy, 361 without nephropathy)using Pyrosequencing.

RESULTS

Twenty-one polymorphisms with a minor allele frequency (MAF)>1%were identified; 14 had a MAF> or =10%. Five htSNPs [c.-1968_69insG, c.43 G-->A (Ala15Thr), c.1092-105 A-->G, c.*1737 G-->A, c.*3711 C-->T] were identified. Haplotype frequencies were similar in case and control groups (likelihood ratio chi2 test,P=0.66).

CONCLUSION

It is unlikely that common polymorphisms of thePAI1 gene strongly influence susceptibility to diabetic nephropathy in the White Type 1 diabetic population.

Phenotypic and genotypic risk factors for cardiovascular events in an incident dialysis cohort

Cardiovascular disease (CVD) remains the major cause of death in patients with end-stage renal disease (ESRD). Traditional risk factors do not explain the high prevalence of CVD in this population, and other non-traditional cardiovascular (CV) risk markers have now been described. Therefore, the potential relationship between CVD and phenotypic and genotypic risk markers was investigated prospectively in incident dialysis patients cohort. The 279 patients (244 on hemodialysis, 35 on peritoneal dialysis) within the Diamant Alpin Dialysis Cohort Study were investigated. Phenotypic and genotypic parameters were determined at dialysis initiation, patients monitored over a 2-year period, and CV events (morbidity and mortality) recorded. Globally, 82 CV events occurred and 26 patients (9.3%) died from CVD, whereas 28 (10%) died from non-CV causes. Previous CV events were strongly predictive of CV events occurrence, whatever patients had had one (hazard ratio (HR) 2, 95% confidence intervals (CI) 1.1-3.5) or more (HR 3.9, 95% CI 2.1-7.1) CV accidents before starting dialysis. Both lipoprotein(a) (HR 1.67, 95% CI 1-2.5) and total plasma homocysteine at cutoff 30 micromol/l (HR 1.7, 95% CI 1.1-2.8) were independent predictors of CV events outcome. In the subgroup of patients with homocysteine < 30 micromol/l, methylenetetrahydrofolate reductase (MTHFR) TT was the sole biological parameter predictive of CV event outcome (HR 2.5, 95% CI 1.1-10, P = 0.03). ESRD patients who enter chronic dialysis with a previous CV event, high total homocysteinemia levels, or MTHFR 677TT genotype must be considered at high risk of incident CV events.

Gene polymorphisms of fibrinolytic enzymes in coal workers' pneumoconiosis

The authors assessed the gene polymorphisms of missense C/T polymorphism in exon 6 of the urokinase-plasminogen activator (PLAU) gene (PLAU P141L), Alu-repeat in intron 8 of the tissue-type plasminogen activator (PLAT) gene (PLAT TPA25 Alu insertion), and 4G/5G in the promoter region of the serine proteinase inhibitor, clade E (SERPINE) or plasminogen activator inhibitor type 1 gene (SERPINE1 -675 4G/5G) in 153 healthy volunteers and 154 retired coal miners with coal miners' pneumoconiosis (CWP). The CWP subjects included 94 individuals with simple pneumoconiosis and 60 individuals with progressive massive fibrosis presenting with worse pulmonary function. The distributions of genotypes of these three genes did not differ between the control and CWP subjects or between subjects with simple pneumoconiosis and those with progressive massive fibrosis. However, by assessing duration of work and its interaction with genotypes by means of logistic regression, the authors found the missense C/T polymorphism in exon 6 of the PLAU gene to be an effect modifier of the association between work duration and the development of progressive massive fibrosis.

Mechanisms of progression and regression of renal lesions of chronic nephropathies and diabetes

The incidence of chronic kidney diseases is increasing worldwide, and these conditions are emerging as a major public health problem. While genetic factors contribute to susceptibility and progression of renal disease, proteinuria has been claimed as an independent predictor of outcome. Reduction of urinary protein levels by various medications and a low-protein diet limits renal function decline in individuals with nondiabetic and diabetic nephropathies to the point that remission of the disease and regression of renal lesions have been observed in experimental animals and even in humans. In animal models, regression of glomerular structural changes is associated with remodeling of the glomerular architecture. Instrumental to this discovery were 3D reconstruction studies of the glomerular capillary tuft, which allowed the quantification of sclerosis volume reduction and capillary regeneration upon treatment. Regeneration of capillary segments might result from the contribution of resident cells, but progenitor cells of renal or extrarenal origin may also have a role. This review describes recent advances in our understanding of the mechanisms and mediators underlying renal tissue repair ultimately responsible for regression of renal injury.

Genetic basis of diabetic nephropathy

Diabetes mellitus is the leading cause of end-stage renal disease. Development and progression of diabetic nephropathy result from a combination of genetic susceptibility and metabolic and hemodynamic abnormalities. In America, some racial and ethnic minorities have a significant burden of diabetic nephropathy, and, although genetic studies suggest that inherited factors play a major role in the pathogenesis of diabetic nephropathy, little information has been gained on the genes and molecular mechanisms involved. The genetic background of diabetic nephropathy is believed to be polygenic, and the genes predisposing to the development and progression of diabetic nephropathy are actively being investigated. New knowledge in identifying and understanding the role of susceptibility gene(s) will provide valuable information that could help develop new preventive and therapeutic strategies.

Progression of chronic kidney disease: can it be prevented or arrested?

Chronic kidney disease constitutes a highly prevalent health problem worldwide. Left untreated, it progresses inexorably to greater levels of severity at variable rates. The morbid impact of chronic kidney disease is heightened by its role as risk factor for cardiovascular disease. In the past two decades, considerable gains have been realized in retarding progression of chronic kidney disease by emphasizing blood pressure control and blockade of the renin-angiotensin system. Notwithstanding, the therapeutic goal of preventing or arresting chronic kidney disease progression remains unfulfilled. Currently attainable rates of decrease in glomerular filtration rate remain at 2 to 8 mL/min/y depending on the underlying disease. It is now believed that to achieve optimal therapeutic targets (proteinuria of <500 mg/day and decrease in glomerular filtration rate of 1 mL/min/y, the average age-related decline) we must introduce novel strategies and a multifaceted approach to treatment that interrupts multiple mechanisms of progression. To this end, and wherever relevant, new approaches to cause-specific treatment must be applied, such as targeted immunosuppression, intensive glycemic control, gene therapy, and enzyme replacement therapy. Furthermore, in all chronic kidney disease, we must interfere more effectively with the multitude of common mechanisms of progression. Established or putative, such approaches include aggressive blood pressure control; advanced renin-angiotensin system blockade; cytokine modulation and antifibrotic therapy; aldosterone blockade; endothelin blockade, nitric oxide modulation and vasopeptidase inhibition; antioxidant therapy; statin therapy; glycosaminoglycan therapy; anemia therapy; dietary restrictions; lifestyle changes; and pharmacogenomic profiling. Such a concerted, multifaceted approach to management might indeed prevent or arrest progression of chronic kidney disease, or even achieve regression of chronic kidney disease.

Multifunctionality of PAI-1 in fibrogenesis: evidence from obstructive nephropathy in PAI-1-overexpressing mice

BACKGROUND

Plasminogen activator inhibitor-1 (PAI-1) has been implicated in the pathogenesis of chronic kidney disease based on its up-regulated expression and on the beneficial effects of PAI-1 inhibition or depletion in experimental models. PAI-1 is a multifunctional protein and the mechanisms that account for its profibrotic effects have not been fully elucidated.

METHODS

The present study was designed to investigate PAI-1-dependent fibrogenic pathways by comparing the unilateral ureteral obstruction model (UUO) (days 3, 7, and 14) in PAI-1-overexpressing mice (PAI-1 tg) to wild-type mice, both on a C57BL6 background.

RESULTS

Following UUO, total kidney PAI-1 mRNA and/or protein levels were significantly higher in the PAI-1 tg mice (N= 6 to 8/group) and fibrosis severity was significantly worse (days 3, 7, and 14), measured both as Sirius red-positive interstitial area (e.g., 10 +/- 3.2% vs. 4.5 +/- 1.0%) (day 14) and total kidney collagen (e.g., 11.1 +/- 1.7 vs. 6.2 +/- 1.3 microg/mg) (day 14). By day 14, the expression of two normal tubular proteins, E-cadherin and Ksp-cadherin, were significantly lower in the PAI-1 tg mice (3.2 +/- 0.5% vs. 11.7 +/- 5.9% and 2.6 +/- 1.6) vs. 6.2 +/- 0.8%, respectively), implying more extensive tubular damage. At least four fibrogenic pathways were differentially expressed in the PAI-1 tg mice. First, interstitial macrophage recruitment was more intense (P < 0.05 days 3 and 14). Second, interstitial myofibroblast density was greater (P < 0.05 days 3 and 7) despite similar numbers of proliferating tubulointerstitial cells. Third, transforming growth factor-beta1 (TGF-beta1) and collagen I mRNA were significantly higher. Finally, urokinase activity was significantly lower (P < 0.05 days 7 and 14) despite similar mRNA levels. Gene microarray studies documented that that the deletion of this single profibrotic gene had far-reaching consequences on renal cellular responses to chronic injury.

CONCLUSION

These data provide further evidence that PAI-1 is directly involved in interstitial fibrosis and tubular damage via two primary overlapping mechanisms: early effects on interstitial cell recruitment and late effects associated with decreased urokinase activity.

Genetics of common progressive renal disease

Familial aggregation of common chronic kidney diseases provides a unique opportunity to investigate the susceptibility genetic and environmental factors. In the past decade, a wealth of new data has become available concerning the genetic susceptibility leading to numerous nephropathies. Knowledge of the genetic components allows better understanding of initiation and progression of these chronic kidney diseases. In addition, one can envision that identification of genetically susceptible individuals might lead to earlier diagnosis and potential reversal of the current epidemic of end-stage renal disease. The goal of the current discussion is to review various issues pertaining to the role of genetic factors in common chronic kidney diseases, as exemplified by two leading causes of end-stage renal diseases worldwide, nephropathy of type 2 diabetes and IgA nephropathy. The genetic and environmental interplay leading to the nephropathies is highlighted.

Distribution of PAI-1 promoter 4G/5G polymorphism in healthy Chinese and functional characterization using a luciferase reporter vector

The aim of this study was to analyze the distribution of plasminogen activator inhibitor-1 (PAI-1) promoter 4G/5G polymorphism in healthy Chinese and compare the transcription activity of the two PAI-1 promoters using luciferase reporter vector pGL(3). PAI-1 promoter 4G/5G polymorphism was analyzed in 77 healthy Chinese using allele-specific polymerase chain reaction (PCR). The PAI-1 promoters from individuals homozygous for the insertion (5G) and deletion (4G) were cloned into luciferase reporter vector pGL(3), respectively. The transcription activities of the two promoters (PAI-1-4G and PAI-1-5G) were then compared using the luciferase reporter vectors expressed in ECV304 and HepG(2) cell lines. Among the 77 healthy Chinese the genotype frequency for 4G/4G, 4G/5G, and 5G/5G was 49.1, 44.1, and 6.5%, respectively. Both of the two PAI-1 promoters cloned into luciferase reporter vector pGL(3), expressed very well both in ECV304 and HepG(2), and have similar basic transcription activity. Thrombin (10-20 U/ml) has no effects on the transcription activity of the two promoters expressed in ECV304, while in the HepG(2) cell line interleukin-1 (IL-1) 158 U/ml increased the transcription activity of PAI-1-4G by 67% (p<0.05, n=5) without effects on PAI-1-5G transcription activity. The distribution of PAI-1 promoter 4G/5G polymorphism in Chinese is obviously different from that in Caucasians with the 4G allele more frequently found in Chinese. PAI-1 promoter 4G/5G polymorphism does not alter basic transcription activity and 4G promoter has increased response to IL-1.

Genotype and allele frequency of PAI-1 promoter polymorphism in healthy subjects from the west of Mexico. Association with biochemical and hematological parameters

We investigated the genotype and allelic frequency of the -675 bp insertion/deletion polymorphism at the PAI-1 gene promoter, in healthy Mexican subjects. It was compared to the lipid profile and hematological parameters, and to other healthy worldwide populations. A Mexican population sample of 110 individuals was studied. Demographic data and clinical characteristics of the subjects were registered. Fasting lipid profile, serum glucose, fibrinogen, hematological parameters and leukocyte genomic DNA isolation from peripheral blood were performed in all the participants. Screening of the PAI-1 genotype was done by PCR and restriction analysis. Genotype 4G/4G, 4G/5G, 5G/5G frequency in Mexican healthy subjects was: 14.55%, 39.09%, 46.36%, respectively, whereas the allelic frequency for 5G allele was 65.9%. A significant lesser frequency for 4G allele and related genotypes (4G/4G and 4G/5G) was established in healthy subjects from Mexico, respect to all the compared populations. A particular genotype and allelic frequency of this PAI-1 polymorphism was established in Mexico. The clinical parameters were not associated according to each genotype of PAI-1.

Diabetic retinopathy in Euro-Brazilian type 2 diabetic patients: relationship with polymorphisms in the aldose reductase, the plasminogen activator inhibitor-1 and the methylenetetrahydrofolate reductase genes

We investigated the relationship between diabetic retinopathy (DR) and three polymorphisms, C(-106)T in the aldose reductase (ALR2) gene, 4G/5G in the plasminogen activator inhibitor-1 (PAI-1) gene and C677T in the methylenetetrahydrofolate reductase (MTHFR) gene, in 210 Euro-Brazilian type 2 diabetic patients. Retinopathy was evaluated by funduscopic examination and genotype analysis was performed using the polymerase chain reaction and allele-specific restriction. Retinopathy was detected in 47% of the patients. There were no significant differences in allele or genotype distributions between patients with or without retinopathy for all polymorphisms. Thus, the three polymorphisms are not related to the presence of DR in Euro-Brazilian type 2 diabetic patients.

Diabetic nephropathy in type 2 diabetes mellitus: risk factors and prevention

Diabetic nephropathy (DN) is responsible for the increasing number of patients on dialysis in developing countries, and is already the most common cause of renal replacement therapy in the developed ones. In this manuscript, we review the risk factors and point out strategies to prevent this microvascular complication in type 2 diabetic patients (DM2). There are some known genetic and non-genetic risk factors related to the development and progression of DN in DM2 patients. Candidate genes have been analysed, but there are still controversy about the genetic markers of the disease. Recognized non-genetic risk factors are poor glycemic, pressoric and lipidic control. Additionally, it has been suggested that the presence of diabetic retinopathy, autonomic neuropathy, smoking habit, higher protein ingestion, and higher normal levels of albuminuria (even within the normal range) are associated with an increased risk of developing DN. Some strategies have been investigated and proved to prevent or at least to postpone DN, such as to control blood pressure, glycemic levels and dyslipidemia. Furthermore, angiotensin-converting enzyme inhibitors and angiotensin-II blockers have independent effects, not explained by blood pressure control alone. Other therapeutic items are to consume a low protein diet and to quit smoking.

PAI-1 4G/5G and ACE I/D gene polymorphisms and the occurrence of myocardial infarction in patients on intermittent dialysis

BACKGROUND

Myocardial infarction (MI) is a leading cause of death, particularly in high-risk settings such as uraemia, in which it is not yet known to what extent genetic factors contribute to the overall risk of MI. We have prospectively evaluated the effect of plasminogen activator inhibitor-1 (PAI-1) 4G/5G and angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphisms on the occurrence of MI in uraemics.

METHODS

All patients undergoing intermittent dialysis in an Italian district were enrolled as subjects. From the same area, 1307 individuals served as controls. Genomic DNA was obtained and ACE I/D and PAI-1 4G/5G gene polymorphisms were determined. After a baseline evaluation, patients were followed for 28.8+/-9.8 months. MIs and other causes of death were recorded.

RESULTS

A total of 461 patients (417 on haemodialysis and 44 on peritoneal dialysis) were investigated. At entry, their mean age was 58.2+/-16.2 years and dialytic age was 82+/-69 months. Genotype frequencies were not different between controls and uraemics and, in the latter group, between patients with or without cardiovascular diseases at baseline evaluation. During the follow-up, 22 fatal and 16 non-fatal MIs were recorded (mean incidence 1.99 and 1.45%/year, respectively). The adjusted risk of fatal and total MI was related to the presence at entry of a history of MI [hazard ratios (HR) 4.3; 95% confidence interval (CI) 1.5-12.0 and HR 6.8; 95% CI: 3.3-14.0, respectively] and to the PAI-1 4/4 genotype (HR 2.8; 95% CI 1.2-6.9 and HR 2.1; 95% CI 1.1-4.2, respectively).

CONCLUSIONS

In end-stage renal disease, PAI-1 4G/5G gene polymorphism may have a significant role in the occurrence of fatal and non-fatal MI.

Association of transforming growth factor-beta (TGF-beta) T869C (Leu 10Pro) gene polymorphisms with type 2 diabetic nephropathy in Chinese

INTRODUCTION

Transforming growth factor-beta (TGF-beta) is known to play a pivotal role in the regulation of extracellular matrix (ECM) accumulation. Since diabetic nephropathy (DMN) is characterized by basement membrane thickening and mesangial expansion, control of ECM deposition is believed to be important in the pathogenesis of the disease. Recently, TGF-beta T869C (Leu 10Pro) gene polymorphism has been identified which may be associated with circulating TGF-beta levels.

METHODS

In order to examine the relationship between TGF-beta gene polymorphism with DMN in Chinese, we carried out a case-control study, which recruited 123 Chinese type 2 diabetic patients with an average duration of diabetes for 12 years. A total of 58 patients who developed DMN (micro- or macroalbuminuria, with or without renal impairment) were compared with 65 diabetic patients without DMN despite similar duration of disease (normoalbuminuric and creatinine <120 micromol/L). TGF-beta T869C (Leu 10Pro) gene polymorphism was determined by polymerase chain reaction (PCR).

RESULTS

Both groups of patients had similar baseline characteristics, including blood pressure, diabetic control, and duration of diabetes. Distribution of TGF-beta T869C (Leu 10Pro) genotype among the whole group is confined to Hardy Weinberg equilibrium. The DMN+ group has higher frequency of TGF-beta CC/CT genotypes than the DMN- group [CC, CT, TT = (DMN+) 46, 45, 9 (%) vs. (DMN-) 37, 37, 26 (%), P < 0.05]. C allele frequency is also higher in the DMN+ group than DMN- group (69% vs. 55%, P < 0.05). The adjusted odds ratio for TGF-beta CC/CT vs. TT genotype to develop DMN is 3.8 (3.2 to 4.4). Multivariate logistic regression analysis [hypertension, gender, age, duration of diabetes, hemoglobin (HbA1c), usage of angiotensin-converting enzyme (ACE) inhibitor, and cholesterol level] showed that TGF-beta genotype (P = 0.03) is an independent predictor for type 2 DMN. Among patients with DMN, those with TGF-beta CC/CT genotypes also had worse renal function and increased risk for macroalbuminuria.

CONCLUSION

Our results suggest that TGF-beta T869C (Leu 10Pro) gene polymorphism is associated with DMN in Chinese.

PAI-1 gene 4G/5G genotype: A risk factor for thrombosis in vessels of internal organs

Although the common 4G/5G polymorphism in the promoter of the PAI-1 gene was suggested to be a risk factor for some of the thrombotic disorders, its significance in the development of thrombosis is still controversial. This study presents the data on a total of 357 patients with different types of thrombosis and 281 unrelated healthy controls. It was found that the 4G/4G genotype is associated with a higher risk of thrombosis (OR, 1.7; 95% CI, 1.1-2.5). Patients were divided into five distinct groups according to the site of thrombosis. Both 4G/4G and 4G/5G genotypes were associated with a higher risk of thrombosis development in a group of 69 patients with internal organ thrombosis (OR, 6.35; 95% CI, 2.5-16.1 and OR, 4.85; 95% CI, 2.0-12.1, respectively). Interestingly, this association was even stronger in a subgroup of 33 patients with portal vein thrombosis (PVT) and 4G/4G and 4G/5G genotypes conferred more than 10- and 6-fold increases in the risk of developing PVT (95% CI: 2.3-47.1 and 1.4-28.8), respectively. No statistically significant association was found between 4G/4G genotype and the groups of deep vein thrombosis (126 patients), cerebral thrombosis (80 patients), retinal thrombosis (72 patients), and purpura fulminans (16 patients). Factor V Leiden or prothrombin G20210A mutations did not emerge as additional risk factors for thrombosis in any of the groups studied. To conclude, this study suggests that there may be an association between 4G/4G and 4G/5G genotypes and the thrombosis in vessels of internal organs especially in the portal veins.

Plasminogen activator inhibitor-1 4G/5G genetic polymorphism does not affect peritoneal transport characteristic

There is evidence that type 1 plasminogen activator inhibitor (PAI-1) may have an important role in peritoneal function. We studied the effect of physiologically relevant PAI-1 promotor polymorphisms on peritoneal permeability. We performed a standard peritoneal equilibration test (PET) in 100 new continuous ambulatory peritoneal dialysis (CAPD) patients. We studied another 48 prevalent CAPD patients who had a baseline PET performed 2 years before; a standard PET was repeated on enrollment. The PAI-1 promotor polymorphism was examined. All patients then were followed up for 16.7 +/- 15.0 months. Prevalences of 4G/4G, 4G/5G, and 5G/5G genotypes were 31.8%, 46.6%, and 21.6%, respectively. Of the 100 new CAPD patients, there was no difference in net ultrafiltration (UF), dialysate-plasma (D/P) creatinine ratio at 4 hours, or mass transfer area coefficient (MTAC) of creatinine among the three genotype groups. D/P creatinine ratios at 4 hours were 0.595 +/- 0.133, 0.607 +/- 0.137, and 0.627 +/- 0.142 for the 4G/4G, 4G/5G, and 5G/5G groups, respectively (one way analysis of variance, P = 0.715). Of the 48 prevalent patients, PAI-1 genotype did not affect the longitudinal change in net UF, D/P creatinine ratio at 4 hours, or MTAC of creatinine. During follow-up, 16 patients developed peritonitis episodes that required Tenckhoff catheter removal. One patient died, 8 patients returned to long-term CAPD therapy after peritonitis resolved, and the other 7 patients developed peritoneal failure and were switched to long-term hemodialysis therapy. PAI-1 promotor genotype did not predict peritoneal failure after an episode of severe peritonitis (chi-square test, P = 0.328). We conclude that PAI-1 promotor polymorphism is not associated with peritoneal transport characteristics in stable peritoneal dialysis patients, longitudinal change in peritoneal transport, or development of peritoneal failure after an episode of severe peritonitis.

Renal outcome in type 2 diabetic patients with or without coexisting nondiabetic nephropathies

OBJECTIVE

To determine the risk factors for adverse renal outcome in type 2 diabetic patients who underwent renal biopsy and were followed-up longitudinally.

RESEARCH DESIGN AND METHODS

We examined 68 consecutive patients with type 2 diabetes during the period of 1985-1999 who underwent renal biopsy for proteinuria > or =1 g/day, renal involvement (proteinuria or renal impairment) at the absence of retinopathy, renal involvement with duration of diabetes < 5 years, or unexplained hematuria of glomerular origin. Their clinical features and underlying renal lesion were correlated with the renal outcome after longitudinal follow-up. Three groups of patients were defined based on their renal pathology: group I consisted of 24 patients (35%) with diabetic glomerulosclerosis (DGS) alone, group II consisted of 13 patients (19%) with nondiabetic nephropathy (NDN) superimposed on DGS, and group III consisted of 31 patients (46%) with NDN alone without evidence of DGS.

RESULTS

After a mean follow-up of 123 months from the diagnosis of type 2 diabetes (74 months from the time of renal biopsy), univariate analysis showed that risk factors for reaching end-stage renal disease (requiring maintenance dialysis, or a serum creatinine [SCr] > or =700 micromol/l) included proteinuria > or = 2g/day (P = 0.0087), SCr >120 micromol/l (P = 0.0005), presence of retinopathy (P < 0.00001) at the time of biopsy, and biopsy showing DGS (groups I and II) (P = 0.035). On multivariate analysis, retinopathy was the only independent variable correlated with end-stage renal failure. This study also showed that the association of hematuria or proteinuria with the absence of retinopathy constitutes the strongest indication for a nondiabetic lesion (positive predictive values of 94%).

CONCLUSIONS

Patients with type 2 diabetes undergoing renal biopsy constitute a heterogeneous group by their clinical presentations and underlying pathology, but longitudinal studies on the renal outcome of these patients remain limited. Our study showed that renal biopsy is indicated in selective diabetic patients because of potentially treatable nephropathy and of a better prognosis than DGS.

Chronic graft dysfunction in renal transplant patients: potential role of plasminogen activator inhibitor type 1

BACKGROUND

Chronic allograft nephropathy is the main cause of long-term kidney graft loss. The plasminogen activator inhibitor type 1 (PAI-1) is a potential fibrogenic molecule whose secretion is regulated by several metabolic, inflammatory, and genetic factors. We aimed to determine whether PAI-1 secretion in renal transplant patients is correlated with the decline in renal function after transplantation.

METHODS

Renal transplant patients (145 male/71 female) were included in the study 1-27 years after transplantation (median of follow-up: 7.35 years). At inclusion, routine clinical and biological data were collected, the 4G/5G polymorphism of the recipient PAI-1 gene was determined, and the PAI-1 plasma level was measured.

RESULTS

The mean rate of decline in renal function was -4.26+/-0.30 ml/min/year. By multiple linear regression analysis, the rate of decline in renal function was significantly correlated with proteinuria (P=0.0176), occurrence of late acute rejection episodes (P=0.0001), and PAI-1 plasma level (P=0.0051). In addition, PAI-1 plasma level was also significantly correlated with body mass index (P=0.038), insulin (P<0.0001), platelet count (P<0.0001), and fibrinogen (P=0.024). The PAI-1 gene polymorphism tested did not influence the rate of decline in renal function after transplantation nor the plasma level of PAI-1 antigen.

CONCLUSION

We conclude that PAI-1, whose secretion is determined in large part by metabolic and inflammatory factors, may be implicated in the rate of decline in renal function after transplantation.

Diabetes mellitus--a special medical challenge from a Chinese perspective

As we enter the new millennium, Asia is being hit by an epidemic of diabetes and its related diseases. The rising prevalence of young onset diabetes which is closely associated with obesity and genetic factors as well as the increased propensity to develop kidney disease are special challenges in the management of Chinese diabetic patients. Although diabetic patients have earlier mortality and increased risks for micro and macrovascular complications, there is strong evidence that these devastating complications can be largely prevented by patient education, periodic assessments and use of appropriate therapeutic agents to optimize metabolic control and improve cardiovascular risk factors. However, a multidisciplinary approach is often required to deliver these complex disease management protocols. Hence, it is not surprising that large scale studies often revealed substandard diabetes management in both the hospital and community settings. This is often due to a combination of factors such as non-adherence to recommended guidelines both by patients and doctors as well as the 'non-urgent' and 'silent nature' of diabetes and its complications. To minimize the impacts of diabetes on quality of life, society productivity and utilization of health care resources, concerted efforts between health care professionals and public bodies are urgently needed to increase awareness, improve standards of care and develop better diagnostics and treatment modalities.

Regulation of vascular bed-specific prothrombotic potential

Hemostasis is the result of interdependent and complex systemic and local endothelial pathways that govern vascular integrity and rheology. A striking feature of hypercoagulable conditions is the focal nature of the resultant thrombotic pathology. Such disorders in hemostasis may be associated with distinct vascular beds, thus implying that the relative combined contribution of individual regulatory pathways may be specific and/or unique to a particular locale in the vasculature. Systemic factors and platelets mediate the formation of fibrin deposition; however, it is the diverse interrelationships in the interaction of these systemic elements with the local endothelial components that dictate vascular bed-specific hemostatic regulation. Indeed, the local activation of coagulation cascades, rather than increases in systemic thrombotic potential, is what leads to fibrin formation in different vascular beds. Hence, the propensity for congenital or acquired disorders to result in local thrombotic pathology is based on the relative contribution of the various hemostatic regulatory pathways in individual vascular beds. The present review highlights the role of local endothelial regulation in the interaction between local and systemic elements that contribute to vascular bed-specific prothrombotic potential.

Contribution of gene polymorphisms in the renin-angiotensin system to macroangiopathy in patients with diabetic nephropathy

The renin-angiotensin system is important in the control of hemodynamic status and pathogenesis of macrovascular disease, which is a major cause of morbidity and mortality in patients with type 2 diabetes with nephropathy. Serum angiotensin-converting enzyme (ACE) and angiotensinogen (Atg) levels are related to their respective gene polymorphisms. Seventy patients with type 2 diabetes with overt nephropathy (serum creatinine >/= 1.5 mg/dL) were studied. Serum ACE activity was measured by the spectrophotometric method. ACE deletion/insertion (D/I) and Atg M235T genotypes were determined by polymerase chain reaction. Patients with and without macroangiopathy were compared. Those with macroangiopathy had increased ACE activity (median, 60.9 U/L; range, 37.9 to 100 U/L versus without macroangiopathy, 47.9 U/L; range, 11.2 to 84.5 U/L; P = 0.01) and prevalence of ACE DD/DI genotypes (DD/DI:II: with macroangiopathy, 61%:39% versus without macroangiopathy, 34%:66%; P = 0.03). Multivariate analysis using age; sex; duration of diabetes; glycemic, blood pressure, and lipid level control; serum creatinine level; and presence of the ACE D allele showed that presence of the D allele (P = 0.03; odds ratio, 1.8; confidence interval, 1.1 to 3.1) and serum creatinine level (P = 0.0007) were independent risk factors for macroangiopathy. Association of the D allele became insignificant after serum ACE activity was included in the analysis in which only serum ACE activity (P = 0.004) and serum creatinine level (P = 0.01) were independent risk factors. Neither Atg M235T nor its synergistic effect with the ACE D allele showed an association with macroangiopathy. In conclusion, the ACE D allele is associated with macroangiopathy in Chinese patients with type 2 diabetes with nephropathy. The association is dependent on its effect on serum ACE activity, which is an independent risk factor for the development of macroangiopathy.

Plasminogen activator inhibitor type 1 is a potential target in renal fibrogenesis

Plasminogen activator inhibitor type 1 is a potential target in renal fibrogenesis. The progression of renal lesions to fibrosis involves several mechanisms, among which the inhibition of extracellular matrix (ECM) degradation appears to play an important role. Two interrelated proteolytic systems are involved in matrix degradation: the plasminogen activation system and the matrix metalloproteinase system. The plasminogen activator inhibitor type 1 (PAI-1), as the main inhibitor of plasminogen activation, regulates fibrinolysis and the plasmin-mediated matrix metalloproteinase activation. PAI-1 is also a component of the ECM, where it binds to vitronectin. PAI-1 is not expressed in the normal human kidney but is strongly induced in various forms of kidney diseases, leading to renal fibrosis and terminal renal failure. Thrombin, angiotensin II, and transforming growth factor-beta are potent in vitro and in vivo agonists in increasing PAI-1 synthesis. Several experimental and clinical studies support a role for PAI-1 in the renal fibrogenic process occurring in chronic glomerulonephritis, diabetic nephropathy, focal segmental glomerulosclerosis, and other fibrotic renal diseases. Experimental models of renal diseases in PAI-1-deficient animals are in progress, and preliminary results indicate a role for PAI-1 in renal fibrogenesis. Inhibition of PAI-1 activity or of PAI-1 synthesis by specific antibodies, peptidic antagonists, antisense oligonucleotides, or decoy oligonucleotides has been obtained in vitro, but needs to be evaluated in vivo for the prevention or the treatment of renal fibrosis.