Associations between endothelial nitric oxide synthase polymorphisms and risk of diabetic nephropathy: an updated meta-analysis.

BACKGROUND: Genetic polymorphism of endothelial nitric oxide synthase (eNOS) has been implicated in the risk of diabetic nephropathy (DN), but the published findings were inconsistent. We performed a comprehensive meta-analysis to derive a more precise estimation of the association between genetic polymorphisms of eNOS and the risk of DN. METHODS: Six online database were researched on the associations between polymorphisms of eNOS (T786C, G894T, 4b/4a) and DN risk. PRISMA statement and Hardy-Weinberg equilibrium assessment were used in this report. Odds ratio and 95% confidence interval were estimated based on the following genetic contrast/models: allelic model, dominant model, recessive model and co-dominant model. The publication bias and sensitivity analysis were also performed to guarantee the statistical power. RESULTS: A total of 49 case-control studies with 11,990/9754/5131 participants for DN/DM/HC group were eligible for meta-analysis (7/25/31 studies for T786C/G984T/4b/a). For the eNOS-T786C, C allele showed a weak association between C allele and DN risk in DN/T2DM group. For eNOS-G894T, there was an association between T allele and DN risk in the global, Asian and African population in DN/T2DM group. For the eNOS-4b/4a, 4a allele was found contributing significantly to increased DN risk in the global population. CONCLUSION: Our comprehensive meta-analysis suggests that three polymorphisms of eNOS may be the increased risk factors of DN development, especially in Asian population and T2DM group.

Differential expression and therapeutic efficacy of microRNA-346 in diabetic nephropathy mice.

Diabetic nephropathy (DN) is a major cause of end-stage renal disease, in which the SMAD signaling pathway plays an important role. The aim of the present study was to identify differentially expressed microRNAs (miRNAs) during the progression of DN and to investigate a selected miRNA in relation to SMAD3/4 and its therapeutic efficacy. The miRNA microarray was used to identify differentially expressed miRNAs in db/db DN mice. Reverse transcription-quantitative polymerase chain reaction and immunoblot analyses were used to detect SMAD3/4 expression. The development of DN in the db/db mice was demonstrated by glucose dysregulation and typical morphological changes in the kidney. miRNA-346 (miR-346) was identified as one of the differentially expressed miRNAs. The expression of SMAD3/4 was significantly attenuated by miR-346 administration and the therapeutic effects of miR-346 were observed in the DN mouse models. miR-346 was identified as a negative regulator of SMAD3/4. SMAD3/4 was upregulated in the renal tissue of db/db mice. The administration of miR-346 attenuated the SMAD3/4 expression in renal tissue and ameliorated the renal function and glomerular histology in DN mice. This study paves the way for clinical studies of miR-346 in DN.

Vascular endothelial growth factor gene polymorphisms and renal cell carcinoma: A systematic review and meta-analysis.

Renal cell carcinoma (RCC) accounts for 3% of all cancer-related mortalities in adults. The risk factors for the development of RCC remain under investigation. Vascular endothelial growth factor (VEGF) is a key mediator of angiogenesis and is crucial for the development and metastasis of tumors, including RCC. VEGF gene polymorphisms may alter VEGF protein concentrations, affect the process of angiogenesis and may be involved in inter-individual variation in carcinogenesis. In the present study, a systematic review and meta-analysis were performed based on published case-control studies in order to estimate the association between VEGF gene polymorphisms and the susceptibility to RCC. A total of five studies that involved eight polymorphisms and were published between January 2000 and December 2012 were identified from PubMed. The results of this systematic review and meta-analysis indicate that the VEGF 936C/T, 1612G/A, -1154G/A, -2549I/D, -460T/C and 405G/C gene polymorphisms are not associated with the risk of RCC. There was no polymorphism in 702C/T and RCC and the -2578C/A gene polymorphism may be associated with an increased risk of RCC. However, due to the limitations of the present study, further high quality case-control studies are warranted to confirm these findings.

Gypenosides inhibit renal fibrosis by regulating expression of related genes in rats with unilateral ureteral obstruction.

BACKGROUND: Transforming growth factor ß1 (TGF-ß1), connective tissue growth factor (CTGF) and Smad7 are potent components of fibrogenesis-related signal transduction pathways. Renal fibrosis is the major pathological change in the rat models with unilateral ureteral obstruction (UUO). Investigating the effects of gypenosides (GPs) on the expression of fibrogenesis-related genes in the UUO model may lead to the development of effective therapy for renal diseases. METHODS: Rats were randomly divided into 3 experimental groups: (i) sham operation rats treated with saline (sham group), (ii) UUO model rats treated with saline (control group) and (iii) UUO model rats treated with GPs (GPs group). Blood urea nitrogen and serum creatinine were detected as the measurement of renal function. UUO-treated kidney tissues were taken for assessment of renal damage index and determination of related gene expression through immunohistochemistry and RT-PCR. RESULTS: UUO-induced tubulointerstitial damage and fibrosis were attenuated by the application of GPs (day 3 and day 7, p<0.01; day 14, p<0.05). The expression of TGF-ß1 and CTGF was significantly reduced with GPs treatment (TGF-ß1, p<0.01; CTGF, p<0.05). Smad7 expression was elevated with GPs treatment at days 7 and 14 (p<0.01). GPs' protective effects on renal function were also demonstrated with this UUO model. CONCLUSIONS: These results suggest that UUO-induced tubulointerstitial fibrosis can be effectively attenuated by GPs application. GPs-mediated down-regulation of TGF-ß1 and CTGF and up-regulation of Smad7 are essential for their effects of antifibrogenesis.

Podocyte injury is suppressed by 1,25-dihydroxyvitamin D via modulation of transforming growth factor-beta 1/bone morphogenetic protein-7 signalling in puromycin aminonucleoside nephropathy rats.

1. Accumulating evidence suggests that vitamin D and its analogues are renoprotective. However, the precise mechanisms and the molecular targets by which active vitamin D exerts its beneficial effects remain obscure. The objective of the present study was to evaluate the effect of active vitamin D on rats with puromycin aminonucleoside (PAN) nephropathy, a model that is characterized by predominant podocyte injury. 2. The PAN nephropathy rats were created by a single intravenous injection of 100 mg/kg PAN. Changes in renal pathology and podocyte numbers were observed. Real-time polymerase chain reaction (PCR) was performed to examine mRNA expression of nephrin, transforming growth factor (TGF)-beta1 and bone morphogenetic protein (BMP)-7. Protein expression of nephrin, TGF-beta1, BMP-7 and p-Smad2/3 and p-Smad1/5/8 was examined by immunofluorescence, immunohistochemistry and western blotting, respectively. Rats were treated with 1,25(OH)(2)D(3) by gastric gavage at a dose of 2.5 microg/kg per day, starting 2 days before PAN injection and continuing throughout the experiment. 3. A single injection of PAN induced massive proteinuria and elevated serum creatinine on Day 7, both of which were significantly suppressed by 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)). Immunofluorescence and real-time PCR of the podocyte-associated protein nephrin revealed reduced and discontinuous staining and this change was reversed by 1,25(OH)(2)D(3). In PAN nephropathy rats, TGF-beta1 and p-Smad2/3 expression was upregulated, whereas that of BMP-7 and p-Smad1/5/8 was downregulated. Treatment with 1,25(OH)(2)D(3) significantly restored BMP-7/Smad signalling while suppressing TGF-beta1/Smad signalling. 4. In conclusion, 1,25(OH)(2)D(3) can ameliorate podocyte damage and proteinuria induced by PAN. The beneficial effects of 1,25(OH)(2)D(3) on podocytes may be attributable, in part, to direct modulation of TGF-beta1/BMP-7 signalling.

[Effect of bone morphogenic protein 7 on nephrin expression and distribution in diabetic rat kidneys].

OBJECTIVE: To evaluate the effect of bone morphogenic protein 7 (BMP-7) on nephrin expression and distribution in diabetic rat kidneys. METHODS: Twenty rats with diabetes mellitus (DM) induced by streptozotocin (STZ) injection were randomly divided into DM model group and BMP-7 treatment group, with another 10 normal rats serving as the normal control group. The rats in BMP-7 group received intraperitoneal human recombinant BMP-7 injections at 30 microg/kg twice a week for 24 consecutive weeks, while normal saline was administered in rats of the other two groups. Blood glucose and 24 hour urinary protein and creatinine (Ccr) were measured at 8, 16 and 24 weeks, and the rats were sacrificed at 24 weeks to obtain the renal tissues for detecting the expression and distribution of nephrin using immunofluorescence assay and RT-PCR and for examining the expressions of transforming growth factor-beta1 (TGF-beta1) and WT1 using immunohistochemistry. RESULTS: Compared with the normal control group, the DM model group showed significantly increased 24 hour urinary protein, kidney to body weight ratio and TGF-beta1 expression, but had lowered Ccr, glomerular podocyte number and nephrin expression. The linear distribution of nephrin along the capillary loops as found in the normal control group became granular in the kidney of diabetic rats. The rats in BMP-7 group showed less urinary protein excretion, lower TGF-beta1 expression and greater glomerular podocyte number than those in the DM group, and the expression and distribution of nephrin remained normal in the kidney. CONCLUSION: Administration of BMP-7 can significantly suppress the down-regulation of nephrin expression and maintain its normal distribution in the podocytes in diabetic rats possibly in association with a direct suppression of TGF-betasignaling.