Michele Rossini

Randomized controlled clinical trial of corticosteroids plus ACE-inhibitors with long-term follow-up in proteinuric IgA nephropathy

BACKGROUND Immunoglobulin A nephropathy (IgAN) is the most common cause of chronic renal failure among primary glomerulonephritis patients. The best treatment for IgAN remains poorly defined. We planned a long-term, prospective, open-label, multicentre, centrally randomized controlled trial to assess whether the combination of prednisone and ramipril was more effective than ramipril alone in patients with proteinuric IgAN. METHODS Ninety-seven biopsy-proven IgAN patients with moderate histologic lesions, 24-h proteinuria > or =1.0 g and estimated glomerular filtration rate (eGFR) > or = 50 ml/min/ 1.73 m(2) were randomly allocated to receive a 6-month course of oral prednisone plus ramipril (combination therapy group) or ramipril alone (monotherapy group) for the total duration of follow-up. The primary outcome was the progression of renal disease defined as the combination of doubling of baseline serum creatinine or end-stage kidney disease (ESKD). The secondary outcomes were the rate of renal function decline defined as the eGFR slope over time, and the reduction of 24-h proteinuria. RESULTS After a follow-up of up to 96 months, 13/49 (26.5%) patients in the monotherapy group reached the primary outcome compared with 2/48 (4.2%) in the combination therapy group. The Kaplan-Meier analysis showed a significantly higher probability of not reaching the combined outcome in the combination therapy group than in the monotherapy group (85.2% versus 52.1%; log-rank test P = 0.003). In the multivariate analysis, baseline serum creatinine and 24-h proteinuria were independent predictors of the risk of primary outcome; treatment with prednisone plus ramipril significantly reduced the risk of renal disease progression (hazard ratio 0.13; 95% confidence interval 0.03-0.61; P = 0.01). The mean rate of eGFR decline was higher in the monotherapy group than in the combination therapy group (-6.17 +/- 13.3 versus -0.56 +/- 7.62 ml/min/ 1.73 m(2)/year; P = 0.013). Moreover, the combined treatment reduced 24-h proteinuria more than ramipril alone during the first 2 years. CONCLUSIONS Our results suggest that the combination of corticosteroids and ramipril may provide additional benefits compared with ramipril alone in preventing the progression of renal disease in proteinuric IgAN patients in the long-term follow-up.

Regression of Glomerulosclerosis with High-Dose Angiotensin Inhibition Is Linked to Decreased Plasminogen Activator Inhibitor-1

The potential and possible mechanisms for regression of existing glomerulosclerosis by angiotensin II type 1 receptor antagonist (AT1RA) and/or angiotensin I converting enzyme inhibitor (ACEI) were investigated. Adult male Sprague Dawley rats underwent 5/6 nephrectomy (Nx). Glomerulosclerosis was assessed by renal biopsy 8 wk later, and rats were divided into groups with equal biopsy sclerosis and treated for the next 4 wk until they were killed at 12 wk as follows: Control with no further treatment (CONT), high-dose AT1RA, high-dose ACEI, and varying AT1RA+ACEI combinations. Hypertension and proteinuria induced by 5/6 Nx were significantly decreased by all treatments, except high-dose ACEI, which showed persistent proteinuria. High-dose AT1RA and ACEI markedly decreased progression of sclerosis, with -2.3% average decrease in sclerosis from biopsy to autopsy in AT1RA versus 194% increase in CONT (P < 0.0001). Glomerulosclerosis regressed, with less severe lesions at the time when the rats were killed than at biopsy in 62% of AT1RA-treated and 57% of ACEI-treated rats. In contrast, only 17 to 33% of rats in combination groups had regression. Alternatively, these data might be viewed as reflecting halting of progression, as some groups had higher BP and proteinuria. However, this potential confounding effect does not negate the effects to achieve regression of sclerosis in these rats. Regression was not explained by changes in mRNA of TGF-beta1 and matrix metalloproteinase-2 and -9 but was linked to decreased tissue inhibitor of metalloproteinase-1 and plasminogen activator inhibitor-1. It is concluded that angiotensin inhibition mediates regression in part by effects on matrix modulation.

Therapeutic Targeting of Classical and Lectin Pathways of Complement Protects from Ischemia-Reperfusion-Induced Renal Damage

Ischemia-reperfusion injury is the major cause of delayed graft function in transplanted kidneys, an early event significantly affecting long-term graft function and survival. Several studies in rodents suggest that the alternative pathway of the complement system plays a pivotal role in renal ischemia-reperfusion injury. However, limited information is currently available from humans and larger animals. Here we demonstrated that 30 minutes of ischemia resulted in the induction of C4d/C1q, C4d/MLB, and MBL/MASP-2 deposits in a swine model of ischemia-reperfusion injury. The infusion of C1-inhibitor led to a significant reduction in peritubular capillary and glomerular C4d and C5b-9 deposition. Moreover, complement-inhibiting treatment significantly reduced the numbers of infiltrating CD163(+), SWC3a(+), CD4a(+), and CD8a(+) cells. C1-inhibitor administration led to significant inhibition of tubular damage and tubular epithelial cells apoptosis. Interestingly, we report that focal C4d-deposition colocalizes with C1q and MBL at the peritubular and glomerular capillary levels also in patients with delayed graft function. In conclusion, we demonstrated the activation and a pathogenic role of classical and lectin pathways of complement in a swine model of ischemia-reperfusion-induced renal damage. Therefore, inhibition of these two pathways might represent a novel therapeutic approach in the prevention of delayed graft function in kidney transplant recipients.

Sirolimus and proteinuria in renal transplant patients: evidence for a dose-dependent effect on slit diaphragm-associated proteins.

Background. The mechanisms underlying the development of proteinuria in renal-transplant recipients converted from calcineurin inhibitors to sirolimus are still unknown. Methods. This is a single-center cohort study. One hundred ten kidney transplant recipients converted from calcineurin inhibitors to sirolimus in the period from September 2000 to December 2005 were included in the study. All patients underwent a graft biopsy before conversion (T0) and a second protocol biopsy 2 years thereafter (T2), according to our standard clinical protocol. On the basis of the changes observed in proteinuria between T0 and T2 (median 70%), the patients were divided into two groups: group I (<70%) and group II (>70%). The authors blinded the sirolimus blood trough levels. We investigated in vivo the effects of sirolimus on nephrin, podocin, CD2ap, and actin protein expression. Slit diaphragm (SD)-associated protein expressions were evaluated in T0 and T2 biopsies. The same analysis was performed in cultured human podocytes treated with different doses of sirolimus (5, 10, 20, and 50 ng/mL). Results. The SD protein expression in group II T2 biopsies was significantly reduced compared with the T0 biopsies and with T2 group I biopsies. In addition, sirolimus blood trough levels directly and significantly correlated with the SD protein expression at T2 graft biopsies. Group II patients presented significantly higher sirolimus blood levels than group I. In vitro study confirmed that sirolimus effect on podocytes was dose dependent. Conclusions. Our data suggest that sirolimus-induced proteinuria may be a dose-dependent effect of the drug on key podocyte structures.

RAPAMYCIN INHIBITS PAI-1 EXPRESSION AND REDUCES INTERSTITIAL FIBROSIS AND GLOMERULOSCLEROSIS IN CHRONIC ALLOGRAFT NEPHROPATHY

Background. Chronic allograft nephropathy (CAN) is characterized by deposition of extracellular matrix (ECM) in all renal compartments. PAI-1 seems to play a pivotal role in ECM turnover in CAN. Rapamycin has been shown to improve long-term graft survival in patients with CAN. The aim of the study was to evaluate the molecular mechanisms underlying the beneficial effects of rapamycin on CAN progression at glomerular and tubulointerstitial level. Methods. After a biopsy-proven CAN diagnosis (T0), 18 patients on calcineurin inhibitors (CNI) were randomly assigned in a 2:1 ratio to continue CNI (6 patients) or to receive rapamycin (RAPA; 12 patients). After 2 years of treatment (T24), all patients underwent a second renal biopsy. Morphometric analysis was conducted at T0 and at T24. PAI-1 expression was evaluated at T0 and T24 by immunohistochemistry. We evaluated the effect of rapamycin on PAI-1 gene expression in cultured proximal tubular cells incubated with CD40L or thrombin, two potential CAN pathogenic mediators. Results. The RAPA group showed a significant regression of glomerulosclerotic lesions and only a 26% increase in interstitial fibrosis after 2 years compared to baseline, whereas the CNI group showed progression of glomerulosclerosis and 112% increase in fibrosis. Glomerular and tubulointerstitial PAI-1 expression was reduced compared to the baseline in the RAPA group, while they were unchanged in the CNI group. In vitro data showed that rapamycin significantly reduced PAI-1 gene expression induced by both CD40L and thrombin in proximal tubular epithelial cells. Conclusions. These data suggest that rapamycin may modulate ECM deposition in CAN reducing PAI-1 expression.

T helper 1, 2 and 17 cell subsets in renal transplant patients with delayed graft function

Ischemia‐reperfusion injury (IRI) in kidney transplantation is the major cause of delayed graft function (DGF), an event associated with an increased risk of acute rejection. The aim of this study was to evaluate T helper (Th) cell phenotype in renal transplants with DGF. T‐bet (Th1), GATA‐3 (Th2) and IL‐17 (Th17) protein expression was investigated in pretransplant biopsies, DGF and acute tubular damage (ATD) caused by calcineurin‐inhibitor toxicity. Intracytofluorimetric analysis of IFN‐γ, IL‐4 and IL‐17 was performed to analyze Th1, Th2 and Th17 responses in peripheral blood mononuclear cells of recipients with early graft function (EGF) and DGF, before (T0) and 24 h after transplantation (T24). In pretransplant biopsies, T‐bet+, GATA‐3+ and IL‐17+ cells were barely detectable. In DGF, T‐bet+ and IL‐17+ cells were significantly increased compared with pretransplant and ATD. More than 90% of T‐bet+ and less then 5% of IL‐17+ cells were CD4+. GATA‐3+ cells were increased to a lower extent. T‐bet+/GATA‐3+ cell ratio was significantly higher in DGF. Peripheral CD4+ IFN‐γ/IL‐4 ratio was significantly decreased in DGF, while CD4+/IL‐17+ cells did not differ between T0 and T24 in DGF. Our data suggest that DGF is characterized by a prevalent Th1 phenotype within the graft. This event might represent a link between DGF and acute rejection.

Cells Derived from Young Bone Marrow Alleviate Renal Aging

Bone marrow-derived stem cells may modulate renal injury, but the effects may depend on the age of the stem cells. Here we investigated whether bone marrow from young mice attenuates renal aging in old mice. We radiated female 12-mo-old 129SvJ mice and reconstituted them with bone marrow cells (BMC) from either 8-wk-old (young-to-old) or 12-mo-old (old-to-old) male mice. Transfer of young BMC resulted in markedly decreased deposition of collagen IV in the mesangium and less β-galactosidase staining, an indicator of cell senescence. These changes paralleled reduced expression of plasminogen activator inhibitor-1 (PAI-1), PDGF-B (PDGF-B), the transdifferentiation marker fibroblast-specific protein-1 (FSP-1), and senescence-associated p16 and p21. Tubulointerstitial and glomerular cells derived from the transplanted BMC did not show β-galactosidase activity, but after 6 mo, there were more FSP-1-expressing bone marrow-derived cells in old-to-old mice compared with young-to-old mice. Young-to-old mice also exhibited higher expression of the anti-aging gene Klotho and less phosphorylation of IGF-1 receptor β. Taken together, these data suggest that young bone marrow-derived cells can alleviate renal aging in old mice. Direct parenchymal reconstitution by stem cells, paracrine effects from adjacent cells, and circulating anti-aging molecules may mediate the aging of the kidney.

Sulodexide ameliorates early but not late kidney disease in models of radiation nephropathy and diabetic nephropathy

BACKGROUND Sulodexide is a glycosaminoglycan with anticoagulant and antithrombotic activities. Although sulodexide reduced albuminuria in patients with type 1 and type 2 diabetes, long-term effects on chronic renal injury are not established. We investigated sulodexide effects and mechanisms in a rat radiation nephropathy model and in the db/db mouse model of diabetic kidney disease. METHODS Sprague-Dawley rats received kidney radiation and were treated as follows: 15 mg/kg/day sulodexide s.c., 6 day/week (SUL) or no treatment (CONT). Subsets of animals were sacrificed after 8 weeks and 12 weeks. Blood pressure, serum creatinine, creatinine clearance (CrCl) and urinary protein excretion were measured every 4 weeks. Sclerosis and plasminogen activator inhibitor-1 (PAI-1) expression were assessed at 8 and 12 weeks, and collagen I, total collagen content and phospho-smad-2 expressions were determined at 12 weeks. Twelve-week-old db/db mice received sulodexide as above or vehicle. Albuminuria and CrCl were assessed at intervals till sacrifice at week 9 with assessment of urinary transforming growth factor-beta (TGF-beta) and glomerular lesions. RESULTS Blood pressure, serum creatinine and CrCl were not different in radiation rat CONT vs SUL at any time. Proteinuria was significantly lower in SUL compared to CONT at 4 and 8 weeks but not at 12 weeks. Sclerosis and PAI-1 expression trended lower in SUL vs CONT at 8 weeks. There was no difference between the groups in sclerosis, collagen I mRNA, total collagen content or PAI-1 expression at 12 weeks. Phospho-smad 2 expression was significantly decreased in SUL compared to CONT at 12 weeks. Db/db mice with or without SUL showed no difference in urinary albumin/creatinine ratio, urine TGF-beta or mesangial matrix expansion. CONCLUSIONS Our data show that sulodexide can reduce the early, but not late, proteinuria in radiation nephropathy in rats. In addition, sulodexide did not affect urine TGF-beta established albuminuria or mesangial matrix expansion in a chronic model of diabetic kidney disease in mice. Although sulodexide may affect TGF-beta activation in radiation nephropathy, this effect appeared insufficient in this model to inhibit the expressions of PAI-1 and collagen and reduce accumulation of extracellular matrix. These results may explain in part its lack of efficacy in recent clinical trials of chronic kidney disease.

Outcomes of Pregnancies after Kidney Transplantation: Lessons Learned from CKD. A Comparison of Transplanted, Nontransplanted Chronic Kidney Disease Patients and Low-Risk Pregnancies: A Multicenter Nationwide Analysis

Background Kidney transplantation (KT) may restore fertility in chronic kidney disease (CKD). The reasons why maternofetal outcomes are still inferior to the overall population are only partially known. Comparison with the CKD population may offer some useful insights for management and counselling. Aim of this study was to analyse the outcomes of pregnancy after KT, compared with a large population of nontransplanted CKD patients and with low-risk control pregnancies, observed in Italy the new millennium. Methods We selected 121 live-born singletons after KT (Italian study group of kidney in pregnancy, national coverage about 75%), 610 live-born singletons in CKD, and 1418 low-risk controls recruited in 2 large Italian Units in the same period (2000-2014). The following outcomes were considered: maternal and fetal death; malformations; preterm delivery; small for gestational age (SGA) baby; need for the neonatal intensive care unit; doubling of serum creatinine or increase in CKD stage. Data were analyzed according to kidney diseases, renal function (staging according to CKD-epidemiology collaboration), hypertension, maternal age, parity, ethnicity. Results Maternofetal outcomes are less favourable in CKD and KT as compared with the low-risk population. CKD stage and hypertension are important determinants of results. Kidney transplantation patients with estimated glomerular filtration rate greater than 90 have worse outcomes compared with CKD stage 1 patients; the differences level off when only CKD patients affected by glomerulonephritis or systemic diseases (“progressive CKD”) are compared with KT. In the multivariate analysis, risk for preterm and early-preterm delivery was linked to CKD stage (2-5 vs 1: relative risk 3.42 and 3.78) and hypertension (RR 3.68 and 3.16) while no difference was associated with being a KT or a CKD patient. Conclusions The maternofetal outcomes in patients with kidney transplantation are comparable with those of nontransplanted CKD patients with similar levels of kidney function impairment and progressive and/or immunologic kidney disease.

The Anti-Fibrotic Effect of Mycophenolic Acid–Induced Neutral Endopeptidase

Mycophenolic acid (MPA) appears to have anti-fibrotic effects, but the molecular mechanisms underlying this are unknown. We prospectively studied 35 stable kidney transplant recipients maintained on cyclosporine and azathioprine. We converted 20 patients from azathioprine to enteric-coated mycophenolate sodium (EC-MPS) and continued the remaining 15 patients on azathioprine. Exploratory mRNA expression profiling, performed on five randomly selected EC-MPS patients, revealed significant upregulation of neutral endopeptidase (NEP), which is an enzyme that degrades angiotensin II. We confirmed these microarray data by measuring levels of NEP expression in all subjects; in addition, we found that NEP gene expression correlated inversely with proteinuria. In an additional 33 patients, glomerular and tubular NEP protein levels from renal graft biopsies were significantly higher among the 13 patients receiving cyclosporine + EC-MPS than among the 12 patients receiving cyclosporine + azathioprine or 8 patients receiving cyclosporine alone. Glomerular NEP expression inversely correlated with glomerulosclerosis and proteinuria, and tubular NEP expression inversely correlated with interstitial fibrosis. Incubation of human proximal tubular cells with MPA increased NEP gene expression in a dose- and time-dependent manner. Moreover, MPA reduced angiotensin II-induced expression of the profibrotic factor plasminogen activator inhibitor-1, and a specific NEP inhibitor completely reversed this effect. Taken together, our data suggest that MPA directly induces expression of neutral endopeptidase, which may reduce proteinuria and slow the progression of renal damage in kidney transplant recipients.