François Glowacki

miR-199a-5p Is upregulated during fibrogenic response to tissue injury and mediates TGFbeta-induced lung fibroblast activation by targeting caveolin-1.

As miRNAs are associated with normal cellular processes, deregulation of miRNAs is thought to play a causative role in many complex diseases. Nevertheless, the precise contribution of miRNAs in fibrotic lung diseases, especially the idiopathic form (IPF), remains poorly understood. Given the poor response rate of IPF patients to current therapy, new insights into the pathogenic mechanisms controlling lung fibroblasts activation, the key cell type driving the fibrogenic process, are essential to develop new therapeutic strategies for this devastating disease. To identify miRNAs with potential roles in lung fibrogenesis, we performed a genome-wide assessment of miRNA expression in lungs from two different mouse strains known for their distinct susceptibility to develop lung fibrosis after bleomycin exposure. This led to the identification of miR-199a-5p as the best miRNA candidate associated with bleomycin response. Importantly, miR-199a-5p pulmonary expression was also significantly increased in IPF patients (94 IPF versus 83 controls). In particular, levels of miR-199a-5p were selectively increased in myofibroblasts from injured mouse lungs and fibroblastic foci, a histologic feature associated with IPF. Therefore, miR-199a-5p profibrotic effects were further investigated in cultured lung fibroblasts: miR-199a-5p expression was induced upon TGFβ exposure, and ectopic expression of miR-199a-5p was sufficient to promote the pathogenic activation of pulmonary fibroblasts including proliferation, migration, invasion, and differentiation into myofibroblasts. In addition, we demonstrated that miR-199a-5p is a key effector of TGFβ signaling in lung fibroblasts by regulating CAV1, a critical mediator of pulmonary fibrosis. Remarkably, aberrant expression of miR-199a-5p was also found in unilateral ureteral obstruction mouse model of kidney fibrosis, as well as in both bile duct ligation and CCl4-induced mouse models of liver fibrosis, suggesting that dysregulation of miR-199a-5p represents a general mechanism contributing to the fibrotic process. MiR-199a-5p thus behaves as a major regulator of tissue fibrosis with therapeutic potency to treat fibroproliferative diseases.

Increased Circulating miR-21 Levels Are Associated with Kidney Fibrosis

MicroRNAs (miRNAs) are a class of noncoding RNA acting at a post-transcriptional level to control the expression of large sets of target mRNAs. While there is evidence that miRNAs deregulation plays a causative role in various complex disorders, their role in fibrotic kidney diseases is largely unexplored. Here, we found a strong up-regulation of miR-21 in the kidneys of mice with unilateral ureteral obstruction and also in the kidneys of patients with severe kidney fibrosis. In addition, mouse primary fibroblasts derived from fibrotic kidneys exhibited higher miR-21 expression level compared to those derived from normal kidneys. Expression of miR-21 in normal primary kidney fibroblasts was induced upon TGFβ exposure, a key growth factor involved in fibrogenesis. Finally, ectopic expression of miR-21 in primary kidney fibroblasts was sufficient to promote myofibroblast differentiation. As circulating miRNAs have been suggested as promising non-invasive biomarkers, we further assess whether circulating miR-21 levels are associated with renal fibrosis using sera from 42 renal transplant recipients, categorized according to their renal fibrosis severity, evaluated on allograft biopsies (Interstitial Fibrosis/Tubular Atrophy (IF/TA). Circulating miR-21 levels are significantly increased in patients with severe IF/TA grade (IF/TA grade 3: 3.0±1.0 vs lower grade of fibrosis: 1.5±1.2; p = 0.001). By contrast, circulating miR-21 levels were not correlated with other renal histological lesions. In a multivariate linear regression model including IF/TA grade and estimated GFR, independent associations were found between circulating miR-21 levels and IF/TA score (ß = 0.307, p = 0.03), and between miR-21 levels and aMDRD (ß = −0.398, p = 0.006). Altogether, these data suggest miR-21 has a key pathogenic role in kidney fibrosis and may represent a novel, predictive and reliable blood marker of kidney fibrosis.

Predictive Factors of Acute Rejection after Early Cyclosporine Withdrawal in Renal Transplant Recipients Who Receive Mycophenolate Mofetil: Results from a Prospective, Randomized Trial

The aim of this randomized, open-labeled trial was to compare the incidence of acute rejection after an early (3 mo posttransplantation) withdrawal of cyclosporine (CsA) or mycophenolate mofetil (MMF) in renal transplantation. Among 218 eligible recipients, 108 nonsensitized, rejection-free patients who were under a triple drug regimen (CsA-MMF-prednisone) and had received a first kidney from a deceased donor were enrolled. At 3 mo after graft, they were gradually withdrawn from CsA (MMF group, n = 54) or MMF (CsA group, n = 54). A graft biopsy and a pharmacokinetic study of CsA and mycophenolic acid were systematically performed before the randomization. At 1 yr, graft and patient survival rates were 100% in each group. Renal function was improved in the MMF group compared with the CsA group (Cockcroft calculated clearance 64.7 +/- 18.7 versus 56.5 +/- 18.0 ml/min; P = 0.023). However, the probability of acute rejection was higher in the MMF group (18.5 versus 5.6%; P = 0.045). The 10 patients who developed acute rejection after CsA withdrawal had a significantly higher incidence of borderline changes on the randomization biopsy than the 44 rejection-free patients (five of 10 versus eight of 44; P = 0.034), and they displayed a lower area under the curve of mycophenolic acid (43 +/- 9 versus 58 +/- 22 mg/h per L; P = 0.045). Multivariate analysis confirmed that borderline changes and area under the curve of mycophenolic acid were significant risk factors of acute rejection after CsA discontinuation. It is concluded that a systematic graft biopsy and a pharmacokinetic study of mycophenolic acid are needed to reduce the risk for acute rejection after CsA withdrawal.

Correction of Postkidney Transplant Anemia Reduces Progression of Allograft Nephropathy

Retrospective studies suggest that chronic allograft nephropathy might progress more rapidly in patients with post-transplant anemia, but whether correction of anemia improves renal outcomes is unknown. An open-label, multicenter, randomized controlled trial investigated the effect of epoetin-β to normalize hemoglobin values (13.0-15.0 g/dl, n=63) compared with partial correction of anemia (10.5-11.5 g/dl, n=62) on progression of nephropathy in transplant recipients with hemoglobin <11.5 g/dl and an estimated creatinine clearance (eCrCl) <50 ml/min per 1.73 m(2). After 2 years, the mean hemoglobin was 12.9 and 11.3 g/dl in the normalization and partial correction groups, respectively (P<0.001). From baseline to year 2, the eCrCl decreased by a mean 2.4 ml/min per 1.73 m(2) in the normalization group compared with 5.9 ml/min per 1.73 m(2) in the partial correction group (P=0.03). Furthermore, fewer patients in the normalization group progressed to ESRD (3 versus 13, P<0.01). Cumulative death-censored graft survival was 95% and 80% in the normalization and partial correction groups, respectively (P<0.01). Complete correction was associated with a significant improvement in quality of life at 6 and 12 months. The number of cardiovascular events was low and similar between groups. In conclusion, this prospective study suggests that targeting hemoglobin values ≥13 g/dl reduces progression of chronic allograft nephropathy in kidney transplant recipients.

CYP3A5 and ABCB1 polymorphisms in donor and recipient: impact on Tacrolimus dose requirements and clinical outcome after renal transplantation

BACKGROUND The effect of potentially relevant genetic polymorphisms, CYP3A5 6986A>G and ABCB1 3435C>T, on Tacrolimus pharmacokinetics and graft clinical outcome was investigated in donor and recipient DNA samples from 209 kidney transplant patients. METHODOLOGY/PRINCIPAL FINDINGS The mean follow-up was 21.8 ± 9 months. The Tacrolimus dose, trough blood concentrations (C0) and C0/dose ratio were only statistically correlated with the recipient CYP3A5 genotype. CYP3A5 and ABCB1 genotypes appeared to have no influence on the incidence of Biopsy Proven Acute Rejection and Delayed Graft Function. Renal function was not affected by CYP3A5 and ABCB1 genotypes. Histological evaluation of biopsies revealed also no significant association between Tacrolimus toxicity features and donor or recipient CYP3A5 and ABCB1 polymorphisms. Tacrolimus sparing appeared to be independent of CYP3A5 and ABCB1 genotypes. CONCLUSIONS/SIGNIFICANCE Recipient CYP3A5 6986A>G polymorphism explains part of the interindividual variability of the pharmacokinetics of Tacrolimus. The clinical outcome at 2-year follow-up does not appear to be related to the donor or recipient CYP3A5 6986A>G and/or ABCB1 3435C>T polymorphisms.

TCF7L2 Polymorphism Associates with New-Onset Diabetes after Transplantation

New-onset diabetes after transplantation (NODAT) is a serious and frequent complication in transplant recipients. Whether NODAT shares the same susceptibility genes as type 2 diabetes is unknown. In this multicenter study, we genotyped 1076 white patients without diabetes at transplantation for 11 polymorphisms that associate with type 2 diabetes. We defined NODAT as a fasting plasma glucose > or =126 mg/dl on at least two occasions or de novo hypoglycemic therapy. We compared clinical and genetic factors between patients who developed NODAT within 6 mo of transplantation (n = 118; incidence 11%) and patients without diabetes (n = 958). In multivariate analysis, NODAT significantly associated with the following characteristics: TCF7L2 polymorphism (odds ratio [OR] 1.60 per each T allele; P = 0.002), age (OR 1.03 per year; P < 0.001), body mass index at transplantation (OR 1.09 per unit; P < 0.001), tacrolimus use (OR 2.26; P < 0.001), and the occurrence of a corticoid-treated acute rejection episode (OR 2.78; P < 0.001). In summary, our data show that the TCF7L2 rs7903146 polymorphism, a known risk factor for type 2 diabetes in the general population, also associates with NODAT.

Influence of cytochrome P450 3A5 (CYP3A5) genetic polymorphism on the pharmacokinetics of the prolonged-release, once-daily formulation of tacrolimus in stable renal transplant recipients.

AbstractBackground and Objective: Tacrolimus is metabolized by cytochrome P450 (CYP) 3A5. The objective of this study was to investigate the influence of the genetic polymorphism of CYP3A5 on the pharmacokinetics of a new modified-release, once-daily formulation of tacrolimus (Advagraf®) after a switch from the immediate-release formulation (Prograf®)Patients and Methods: This was a prospective, single-centre, open-label study in stable kidney transplant recipients. Seventeen ‘expressor’ patients (CYP3A5*1/*3 or *1/*1) were matched to 15 ‘non-expressor’ patients (CYP3A5*3/*3). Exposure variables (concentrations and area under the blood concentration-time curve from 0 to 24 hours [AUC24]) were obtained before and 15 days after the switch. Delay since grafting was similar for both groups of patients (expressors: 49±24 months; non-expressors: 45±22 months). Results: During administration of tacrolimus as Prograf® or Advagraf®, the mean tacrolimus daily dose was significantly higher and the dose-adjusted AUC24 was significantly lower in the expressor group. Following the switch to Advagraf®, there was a significant decrease in the dose-adjusted AUC24 for both non-expressor (5910 ± 3019 vs 5334 ± 2668 ng · h/mL per mg/kg/day; p = 0.041) and expressor patients (3701 ± 1409 vs 3273 ± 1372 ng · h/mL per mg/kg/day; p = 0.03). In the non-expressor group, mean blood trough concentration (C0) was comparable for both formulations while it decreased significantly in the expressor group after the switch (8.2 ± 2.2 vs 6.3 ± 2.5ng/mL; p = 0.02). However, a good correlation between AUC24 and C0 was observed for both Advagraf® and Prograf® regardless of CYP3A5 genotype. Conclusion: Tacrolimus exposure significantly decreases after a switch from Prograf® to Advagraf®, on a milligram-for-milligram basis, in CYP3A5 expressor recipients. Consequently, these patients should be carefully monitored.

Long-term Kidney Disease Outcomes in Fibrillary Glomerulonephritis: A Case Series of 27 Patients

BACKGROUND Fibrillary glomerulonephritis (GN) is a rare disorder with poor renal prognosis. Therapeutic strategies, particularly the use of immunosuppressive drugs, are debated. STUDY DESIGN Case series. SETTING & PARTICIPANTS 27 adults with fibrillary GN referred to 15 nephrology departments in France between 1990 and 2011 were included. All patients were given renin-angiotensin system blockers and 13 received immunosuppressive therapy, including rituximab (7 patients) and cyclophosphamide (3 patients). OUTCOMES & MEASUREMENTS Clinical and histologic features of patients and kidney disease outcome. Renal response was defined as a >50% decrease in 24-hour proteinuria with <15% decline in estimated glomerular filtration rate (eGFR). RESULTS All patients presented with proteinuria, associated with nephrotic syndrome (41%), hematuria (73%), and hypertension (70%). Baseline median eGFR was 49 mL/min/1.73 m(2). Eight patients had a history of autoimmune disease and none had evidence of hematologic malignancy during follow-up. Light microscopic studies showed mesangial GN (70%), predominant pattern of membranous GN (19%), or membranoproliferative GN (11%). By immunofluorescence, immunoglobulin G (IgG) deposits (IgG4, 15/15; IgG1, 9/15) were polyclonal in 25 cases. Serum IgG subclass distribution was normal in the 6 patients tested. After a median 46-month follow-up, renal response occurred in 6 of 13 patients who received immunosuppressive therapy with rituximab (5 patients) or cyclophosphamide (1 patient). Of these, 5 had a mesangial or membranous light microscopic pattern, and median eGFR before therapy was 76 mL/min/1.73 m(2). In contrast, chronic kidney disease progressed in 12 of 14 patients who were not given immunosuppressive therapy, 10 of whom reached end-stage renal disease. LIMITATIONS Number of patients, retrospective study, use of multiple immunosuppressive regimens. CONCLUSIONS The therapeutic approach in fibrillary GN remains challenging. The place of immunosuppressive therapy, particularly anti-B-cell agents, needs to be assessed in larger collaborative studies.

Anti-viral therapy in haemodialysed HCV patients: efficacy, tolerance and treatment strategy.

Aliment Pharmacol Ther 2011; 34: 454–461

Isolation and characterization of a primary proximal tubular epithelial cell model from human kidney by CD10/CD13 double labeling.

Renal proximal tubular epithelial cells play a central role in renal physiology and are among the cell types most sensitive to ischemia and xenobiotic nephrotoxicity. In order to investigate the molecular and cellular mechanisms underlying the pathophysiology of kidney injuries, a stable and well-characterized primary culture model of proximal tubular cells is required. An existing model of proximal tubular cells is hampered by the cellular heterogeneity of kidney; a method based on cell sorting for specific markers must therefore be developed. In this study, we present a primary culture model based on the mechanical and enzymatic dissociation of healthy tissue obtained from nephrectomy specimens. Renal epithelial cells were sorted using co-labeling for CD10 and CD13, two renal proximal tubular epithelial markers, by flow cytometry. Their purity, phenotypic stability and functional properties were evaluated over several passages. Our results demonstrate that CD10/CD13 double-positive cells constitute a pure, functional and stable proximal tubular epithelial cell population that displays proximal tubule markers and epithelial characteristics over the long term, whereas cells positive for either CD10 or CD13 alone appear to be heterogeneous. In conclusion, this study describes a method for establishing a robust renal proximal tubular epithelial cell model suitable for further experimentation.