Association of C-509T and T869C polymorphisms of transforming growth factor-beta1 gene with chronic allograft nephropathy and graft survival in Korean renal transplant recipients

Autologous bone marrow-derived mesenchymal stem cells for interstitial fibrosis and tubular atrophy: a pilot study

Background

Mesenchymal stem cells (MSCs)-based therapy has shown promising results for renal injury. In this study, the efficacy and safety of autologous bone marrow-derived mesenchymal stem cells (BM-MSCs) in treating nonspecific interstitial fibrosis and tubular atrophy (IFTA) were evaluated.

Methods

From March 2011 to January 2013, 11 renal transplanted patients with IFTA were recruited. At baseline, patients were given one intra-arterial infusion of BM-MSCs; 7 days and 1 month later, another two intravenous infusions of cells were followed. Serum creatinine, creatinine clearance rate, and serum cystatin-C at baseline and 7 days, 1 month, 3 months, 6 months, and 12 months after the intra-arterial infusion of BM-MSCs were used to assess renal function. At baseline and 6 months, histological examination based on hematoxylin-eosin, Masson’s trichrome and periodic acid-Schiff staining and immunohistochemistry for transforming growth factor β1 (TGF-β1) and connective tissue growth factor (CTGF) was performed. Adverse events were recorded to evaluate the safety of BM-MSCs treatment.

Results

At 12 months, the renal function of 6 patients (54.5%) was improved, 3 (27.3%) were stable and 2 (18.2%) were worsened. At 6 months, the mean IFTA scores of all participators were similar with the baseline (1.73 ± 0.41 vs.1.50 ± 0.0.77, p = 0.242); however, it was significantly decreased when only 6 patients with improved renal function were analyzed (1.67 ± 0.41 vs. 1.08 ± 0.20, p = 0.013). Besides, decreased expression of TGF-β1 and CTGF were also observed at 6 months. During 1 year follow-up period, only two minor complications including infection and allergy were observed.

Conclusion

Our results demonstrated that autologous BM-MSCs are safe and beneficial for IFTA patients. Abbreviations: MSCs: mesenchymal stem cells; BM-MSCs: marrow-derived mesenchymal stem cells; IFTA: interstitial fibrosis and tubular atrophy; CAN: chronic allograft nephropathy; CNIs: calcineurin inhibitors; Scr: serum creatinine; CCr: creatinine clearance rate; Cys-C: cystatin-C; TGF-β1: transforming growth factor β1; CTGF: connective tissue growth factor

Risk factors for calcineurin inhibitor nephrotoxicity after renal transplantation: a systematic review and meta-analysis

Background

Nephrotoxicity of calcineurin inhibitors (CNIs) is the major concern for long-term allograft survival despite its predominant role in current immunosuppressive regime after renal transplantation. CNI nephrotoxicity is multifactorial with demographic, environmental, and pharmacogenetic flexibility, whereas studies indicating risk factors for CNI nephrotoxicity obtained incomplete or conflicting results.

Methods

A systematic review and meta-analysis of risk factors for CNI nephrotoxicity was performed on all retrieved studies through a comprehensive research of network database. Data were analyzed by Review Manager 5.2 with heterogeneity assessed using the Cochrane Q and I² tests. CNI nephrotoxicity was primarily indicated with protocol biopsy or index-based clinical diagnosis, and the secondary outcome was defined as delayed graft function.

Results

Twelve observational studies containing a total of 2,849 cases were identified. Donor age (odds ratio [OR], 1.01; 95% CI, 1.01-1.03; p=0.02), recipient zero-time arteriosclerosis (OR, 1.44; 95% CI, 1.04-1.99; p=0.03), and CYP3A5*3/*3 genotype (OR, 2.80; 95% CI, 2.63-2.98; p=0.00) were confirmed as risk factors for CNI nephrotoxicity. Subgroup and sensitivity analysis claimed donor age as a significant contributor in Asian and Caucasian areas.

Conclusion

Older donor age, recipient zero-time arteriosclerosis, and CYP3A5*3/*3 genotype might add up the risk for CNI nephrotoxicity, which could be interpreted into a robust biomarker system.

Contribution of genetics and epigenetics to progression of kidney fibrosis

Chronic kidney disease (CKD) which can lead to end-stage renal failure remains a principal challenge in Nephrology. While mechanistic studies provided extensive insights into the common pathways of fibrogenesis which underlie the progression of CKD, these pre-clinical studies fail to fully explain the vastly different progression slopes of individual patients. Recent studies provide evidence that genetic polymorphisms and epigenetic variations determine the individual susceptibility of patients to develop chronic progressive kidney disease. Here, we review recent insights that were provided by genome-wide association studies (GWASs), gene-linkage studies and epigenome analysis. The progression of CKD towards end-stage renal failure remains a principal unsolved problem in Nephrology as effective therapies and predictive tests are still not available [ 1, 2]. Chronic progressive kidney disease is caused by a wide range of diseases, with diabetes mellitus, hypertension and primary glomerulopathies being the most common causes in the Western world [ 3]. Infections, physical obstruction, interstitial nephritides and genetic cystic kidney diseases are also common causes of end-stage renal disease (ESRD) [ 3]. Regardless of the primary underlying disease, chronically injured kidneys are histomorphologically characterized by tubulointerstitial fibrosis [ 1]. In fact, the extent of tubulointerstitial fibrosis is the best predictor for kidney survival, irrespective of the underlying disease. For this reason, fibrosis is considered the common pathway of chronic progressive kidney disease [ 1]. Fibrogenesis is a pathological scarring process which involves accumulation of activated fibroblasts, excessive deposition of extracellular matrix, failed regeneration of tubular epithelium, microvascular rarefaction and (mostly sterile) inflammation [ 4]. Fibrogenesis depends on a complex interaction of the involved cell types which is orchestrated by an extensive network of growth factors and signalling pathways (which are reviewed extensively elsewhere) [ 1]. In view of the detailed mechanistic knowledge of the pathways that orchestrate renal fibrogenesis, it is puzzling why progression rates of CKD differ dramatically among patients with identical underlying diseases [ 1, 2]. The fibrotic pathways are known, but the switches that control their intensities and which determine the speed at which fibrosis moves along the progression slope are not yet understood [ 1, 2]. The concept that genetic polymorphisms are the basis for individual progression rates of CKD is an obvious and attractive one. Distinct susceptibilities of different mouse and rat strains to experimental CKD are a strong testament of the impact of genetic variations on renal fibrogenesis. Identification of the underlying genetic polymorphisms and mechanistic proof of their involvement in the progression of CKD, however, is an ongoing challenge. There are two basic approaches: one strategy is to perform unbiased screening to identify genes which are associated with chronic progressive kidney disease and to then prove their mechanistic relevance in experimental studies ('genotype to phenotype approach'). The second strategy is to selectively analyse polymorphisms of genes which have been identified in mechanistic studies as drivers of renal fibrogenesis with regard to their association with CKD (phenotype to genotype approach). The puzzling observation, however, is that genetic analysis and mechanistic studies so far rarely complement each other. The current state of affairs is reviewed in more detail below.

The relationship between the TGF-beta1 gene -509C/T polymorphism and tubulointerstitial damage resulting from primary nephrotic syndrome

BACKGROUND

The aim of this study was to investigate the correlation between the transforming growth factor (TGF)-beta1 gene -509C/T polymorphism and the susceptibility to primary nephrotic syndrome (PNS), and in particular to the severe degree of tubulointerstitial damage (TID) seen in Chinese.

METHODS

Ninety-eight PNS patients and 128 normal controls were studied. The extent of tubulointerstitial changes was evaluated and patients were divided into two groups according to the severe or mild degree of TID. The TGF-beta1gene -509C/T polymorphism was detected with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique, and the serum level of TGF-beta1 was determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

No statistical differences in genotype or allele frequency of the TGF-beta1 gene -509C/T were found between PNS and normal subjects. However, T allele and CT + T T genotype frequency were higher in the PNS with severe TID than the mild TID and controls. Additionally, the serum concentration of TGF-beta1 was significantly higher in the PNS with severe TID group than the other two groups and in the T T genotype individuals than the CC and CT genotype individuals. A logistic regression analysis demonstrated that TGF-beta1 gene -509C/T genotype was the risk factor of TID in PNS patients [OR (odd ratio) 2.34, confidence interval (CI) 0.98-3.46, p = 0.012]. CONCLUSION. TGF-beta1 gene -509C/T polymorphism was associated with severe TID. The higher value in serum concentration of TGF-beta1 was also associated with severe TID and the T T genotype/T allele. T allele gene might be the important risk factor for susceptibility.