Early Conversion From Calcineurin Inhibitor- to Everolimus-Based Therapy Following Kidney Transplantation: Results of the Randomized ELEVATE Trial.

In a 24-month, multicenter, open-label, randomized trial, 715 de novo kidney transplant recipients were randomized at 10-14 weeks to convert to everolimus (n = 359) or remain on standard calcineurin inhibitor (CNI) therapy (n = 356; 231 tacrolimus; 125 cyclosporine), all with mycophenolic acid and steroids. The primary endpoint, change in estimated glomerular filtration rate (eGFR) from randomization to month 12, was similar for everolimus versus CNI: mean (standard error) 0.3(1.5) mL/min/1.732 versus -1.5(1.5) mL/min/1.732 (p = 0.116). Biopsy-proven acute rejection (BPAR) at month 12 was more frequent under everolimus versus CNI overall (9.7% vs. 4.8%, p = 0.014) and versus tacrolimus-treated patients (2.6%, p < 0.001) but similar to cyclosporine-treated patients (8.8%, p = 0.755). Reporting on de novo donor-specific antibodies (DSA) was limited but suggested more frequent anti-HLA Class I DSA under everolimus. Change in left ventricular mass index was similar. Discontinuation due to adverse events was more frequent with everolimus (23.6%) versus CNI (8.4%). In conclusion, conversion to everolimus at 10-14 weeks posttransplant was associated with renal function similar to that with standard therapy overall. Rates of BPAR were low in all groups, but lower with tacrolimus than everolimus.

Sterile leukocyturia is associated with interstitial fibrosis and tubular atrophy in kidney allograft protocol biopsies.

Kidney allograft interstitial fibrosis and tubular atrophy (IF/TA) is associated with a poorer renal function and outcome. In the current clinical practice, an early diagnosis can only be provided by invasive tests. We aimed to investigate the association of sterile leukocyturia with Banff criteria histological findings in kidney allograft protocol biopsies. We studied 348 allograft biopsies from two different European countries performed at 8.5 + 3.5 months after transplantation. In these cases, the presence of sterile leukocyturia (Leuc+, n = 70) or no leukocyturia (Leuc-, n = 278) was analyzed and related to Banff elementary lesions. Only IF/TA was significantly different between Leuc+ and Leuc- groups. IF/TA was present in 85.7% of Leuc+ and 27.7% of Leuc- patients (p < 0.001). IF/TA patients had higher serum creatinine and presence of proteinuria (p < 0.05). Independent predictors of IF/TA were donor age, donor male sex, serum creatinine and Leuc+ (hazard ratio 18.2; 95% confidence interval, 8.1-40.7). The positive predictive value of leukocyturia for predicting IF/TA was 85.7% whereas the negative predictive value was 72.3%. These studies suggest that leukocyturia is a noninvasive and low-cost test to identify IF/TA. An early diagnosis may allow timely interventional measures directed to minimize its impact and improve graft outcome.

Dendritic cells phenotype fitting under hypoxia or lipopolysaccharide; adenosine 5'-triphosphate-binding cassette transporters far beyond an efflux pump.

This study examines adenosine 5'-triphosphate-binding cassette (ABC) transporters as a potential therapeutic target in dendritic cell (DC) modulation under hypoxia and lipopolysaccharide (LPS). Functional capacity of dendritic cells (DCs) (mixed lymphocyte reaction: MLR) and maturation of iDCs were evaluated in the presence or absence of specific ABC-transporter inhibitors. Monocyte-derived DCs were cultured in the presence of interleukin (IL)-4/granulocyte-macrophage colony-stimulating factor (GM-CSF). Their maturation under hypoxia or LPS conditions was evaluated by assessing the expression of maturation phenotypes using flow cytometry. The effect of ABC transporters on DC maturation was determined using specific inhibitors for multi-drug resistance (MDR1) and multi-drug resistance proteins (MRPs). Depending on their maturation status to elicit T cell alloresponses, the functional capacity of DCs was studied by MLR. Mature DCs showed higher P-glycoprotein (Pgp) expression with confocal microscopy. Up-regulation of maturation markers was observed in hypoxia and LPS-DC, defining two different DC subpopulation profiles, plasmacytoid versus conventional-like, respectively, and different cytokine release T helper type 2 (Th2) versus Th1, depending on the stimuli. Furthermore, hypoxia-DCs induced more B lymphocyte proliferation than control-iDC (56% versus 9%), while LPS-DCs induced more CD8-lymphocyte proliferation (67% versus 16%). ABC transporter-inhibitors strongly abrogated DC maturation [half maximal inhibitory concentration (IC50 ): P-glycoprotein inhibition using valspodar (PSC833) 5 µM, CAS 115104-28-4 (MK571) 50 µM and probenecid 2·5 µM], induced significantly less lymphocyte proliferation and reduced cytokine release compared with stimulated-DCs without inhibitors. We conclude that diverse stimuli, hypoxia or LPS induce different profiles in the maturation and functionality of DC. Pgp appears to play a role in these DC events. Thus, ABC-transporters emerge as potential targets in immunosuppressive therapies interfering with DCs maturation, thereby abrogating innate immune response when it is activated after ischaemia.

Long-term results of biopsy-guided selection and allocation of kidneys from older donors in older recipients.

In our old-for-old program, we discard or allocate older extended criteria donor kidneys to single (SKT) or dual kidney transplantation (DKT) depending on histological Remuzzi's score in recipients older than 60 years. Here, we analyze the long-term results of this program and try to identify independent predictors of patient and graft survival. Between December 1996 and January 2008, we performed 115 SKT and 88 DKT. Discard rate was 15%. Acute rejection incidence was higher in SKT than in DKT (22.6% vs. 11.4%, p = 0.04). Renal function was better in DKT than in SKT up to 5 years after transplantation. Surgical complications were frequent in DKT. Ten-year cumulative graft survival was significantly lower in the SKT group (31% vs. 53%, p = 0.03). In SKT, histological score 4 provided similar graft survival than 3 or less, whereas in DKT score 4, 5 or 6 displayed similar outcome. Finally, independent predictors of graft survival were history of major adverse cardiac event and 1-year serum creatinine, rather than SKT or DKT. In conclusion, this biopsy-guided old-for-old strategy resulted in acceptable long-term graft survival. Our results suggest that DKT should be considered for scores of 5 or 6 only.

Hepatocyte growth factor gene therapy enhances infiltration of macrophages and may induce kidney repair in db/db mice as a model of diabetes.

AIMS/HYPOTHESIS: We previously demonstrated hepatocyte growth factor (HGF) gene therapy was able to induce regression of glomerulosclerosis in diabetic nephropathy through local reparative mechanisms. The aim of this study was to test whether bone-marrow-derived cells are also involved in this HGF-induced reparative process. METHODS: We have created chimeric db/db mice as a model of diabetes that produce enhanced green fluorescent protein (EGFP) in bone marrow cells. We performed treatment with HGF gene therapy either alone or in combination with granulocyte-colony stimulating factor, in order to induce mobilisation of haematopoietic stem cells in these diabetic and chimeric animals. RESULTS: We find HGF gene therapy enhances renal expression of stromal-cell-derived factor-1 and is subsequently associated with an increased number of bone-marrow-derived cells getting into the injured kidneys. These cells are mainly monocyte-derived macrophages, which may contribute to the renal tissue repair and regeneration consistently observed in our model. Finally, HGF gene therapy is associated with the presence of a small number of Bowman's capsule parietal epithelial cells producing EGFP, suggesting they are fused with bone-marrow-derived cells and are contributing to podocyte repopulation. CONCLUSIONS/INTERPRETATION: Altogether, our findings provide new evidence about the therapeutic role of HGF and open new opportunities for inducing renal regeneration in diabetic nephropathy.

Intragraft regulatory T cells in protocol biopsies retain foxp3 demethylation and are protective biomarkers for kidney graft outcome.

Presence of subclinical rejection (SCR) with IF/TA in protocol biopsies of renal allografts has been shown to be an independent predictor factor of graft loss. Also, intragraft Foxp3+ T(reg) cells in patients with SCR has been suggested to differentiate harmful from potentially protective infiltrates. Nonetheless, whether presence of Foxp3 T(reg) cells in patients with SCR and IF/TA may potentially protect from a deleterious graft outcome has not yet been evaluated. This is a case-control study in which 37 patients with the diagnosis of SCR and 68 control patients with no cellular infiltrates at 6-month protocol biopsies matched for age and time of transplantation were evaluated. We first confirmed that numbers of intragraft Foxp3-expressing T cells in patients with SCR positively correlates with Foxp3 demethylation at the T(reg) -specific demethylation region. Patients with SCR without Foxp3+ T(reg) cells within graft infiltrates showed significantly worse 5-year graft function evolution than patients with SCR and Foxp3+ T(reg) cells and those without SCR. When presence of SCR and IF/TA were assessed together, presence of Foxp3+ T(reg) could discriminate a subgroup of patients showing the same graft outcome as patients with a normal biopsy. Thus, presence of Foxp3+ T(reg) cells in patients with SCR even with IF/TA is associated with a favorable long-term allograft outcome.

In vivo therapeutic efficacy of intra-renal CD40 silencing in a model of humoral acute rejection.

The humoral branch of the immune response has an important role in acute and chronic allograft dysfunction. The CD40/CD40L costimulatory pathway is crucial in B- and T- alloresponse. Our group has developed a new small interfering RNA (siRNA) molecule against CD40 that effectively inhibits its expression. The aim of the present study was to prevent rejection in an acute vascular rejection model of kidney transplant by intra-graft gene silencing with anti-CD40 siRNA (siCD40), associated or not with sub-therapeutic rapamycin. Four groups were designed: unspecific siRNA as control; sub-therapeutic rapamycin; siCD40; and combination therapy. Long-surviving rats were found only in both siCD40-treated groups. The CD40 mRNA was overexpressed in control grafts but treatment with siCD40 decreased its expression. Recipient spleen CD40+ B-lymphocytes were reduced in both siCD40-treated groups. Moreover, CD40 silencing reduced donor-specific antibodies, graft complement deposition and immune-inflammatory mediators. The characteristic histological features of humoral rejection were not found in siCD40-treated grafts, which showed a more cellular histological pattern. Therefore, the intra-renal effective blockade of the CD40/CD40L signal reduces the graft inflammation as well as the incidence of humoral vascular acute rejection, finally changing the type of rejection from humoral to cellular.

[Growth factors and renal regeneration]. / Factores de crecimiento y regeneración renal.

Cell replenishment is critical for adult tissue repair after damage. In some organs this process is facilitated by stem cells. In contrast to the liver, the kidney has limited regeneration capacity and has even been considered over several years as not being able to regenerate itself. Nevertheless, there are several recent studies suggesting the presence of stem cells in the adult kidney. Stem cell renal niches have been identified in the renal papillae in animals as well as in the urinary pole of the Bowman's capsule in humans (CD24+CD133+ stem cells). Although these cells may contribute to organ regeneration, how these cells exert this effect and their role after kidney injury is not known. Nevertheless, renal stem cells may be therapeutic targets for treatment of renal diseases. On the other hand, bone-marrow-derived stem cells may also contribute to renal repair, particularly mesenchymal stem cells. However, the mechanism for producing such effect has not been elucidated. Some studies suggest there is cell fusion between bone marrow and resident tubular cells; others suggest that bone marrow cells are able to differentiate in resident cells, while some authors propose bone marrow cells facilitate organ regeneration by a paracrine action; that is by secreting growth factors such as HGF, VEGF and IGF1. All these secreted molecules would provide a regenerative milieu able to constrain renal damage and to amplify stem cells migration to the damaged organ.

[Prevalence of cardiovascular disease in uraemia and relevance of cardiovascular risk factors]. / Prevalencia de enfermedad cardiovascular en la uremia y relevancia de los factores de riesgo cardiovascular.

AIM: To evaluate the prevalence of cardiovascular disease (CVD) and its association with cardiovascular risk factors, as well as their control in end-stage renal disease (ESRD) patients under maintenance hemodialysis (HD). PATIENTS AND METHODS: A total of 265 patients with ESRD on maintenance HD from a University Hospital and 4 dialysis units were included in this multicenter and cross-sectional study that analyzed the prevalence of CVD and the possible association with classic and new cardiovascular risk factors. Usual biochemical and haemathological parameters were analyzed, as well as plasma levels of homocysteine, troponin-I, BNP, lipoprotein(a), C reactive protein, IL-6, fibrinogen, asymmetrical dimethylarginine (ADMA), advanced oxidation protein products (AOPP), malondialdehyde, adiponectin, osteoprotegerin, and fetuin. In a subset of patients an echocardiography and carotid artery Doppler echography were also performed. RESULTS: The prevalence of CVD was 52.8%. Factors positively associated with prevalent CVD were age, BMI, left ventricular hypertrophy, hypertension, dyslipidemia and diabetes mellitus, dialysis vintage, Charlson s comorbility index, levels of fibrinogen, osteoprotegerin, BNP and CRP, as well as carotid intima-media thickness, left ventricular mass and pulse pressure. Factors negatively associated with prevalent CVD were: previous renal transplant, ejection fraction or levels of LDL-c and phosphorous. In the multivariate analysis dyslipidemia, left ventricular hypertrophy, age and LDL-c (negatively) were associated with CVD. CONCLUSIONS: In HD patients the prevalence of CVD is high and is associated with the presence of cardiovascular risk factors and subclinical CVD.

Tubular epithelial cells transfected with hHGF counteracts monocyte chemotactic protein-1 up-regulation after hypoxia/reoxygenation insult.

Acute kidney injury (AKI) which is mainly produced by nephrotoxic or ischemic insults is correlated with a high mortality and morbidity. Proximal tubular epithelial cells (PTEC) play a major role. They are the main target of ischemia/reperfusion injury. PTECs have also been proposed as the effectors of AKI reversibility, but also as the creator of the inflammatory milieu: cytokine, chemokine, and complement expression. An important chemokine implicated in this process is monocyte chemotactic protein-1 (MCP-1) due to its ability to recruit and activate monocytes. Hepatocyte growth factor (HGF) is a pleiotropic factor with mitogenic, anti-apoptotic, and proliferative effects which has recently been studied for its anti-inflammatory and antifibrogenic effects. Our aim was to evaluate the potential inflammatory effect of hypoxia and reoxygenation on rat PTECs. We created a stable human HGF (hHGF) expressing PTEC line that emulated in vivo transfection and analyzed the role of this cell type in the induction and reversibility of AKI. Our results showed the efficiency of transfection with the hHGF gene to promote sustained expression of the protein in the medium (7627.13 +/- 1144.078 to 8211.3 +/- 795.37 pg/mL). When rat PTECs were under a hypoxia/reoxygenation insult, MCP-1 was highly overexpressed (4479.3 +/- 154.3 pg/mL of protein and 5.099 +/- 1.23 times control gene expression). Transfected cells abrogated this effect (288.7 +/- 13.5 pg/mL and 1.169 +/- 0.0759 times control). In conclusion, we observed that the hypoxia/reoxygenation insult stimulated MCP-1 protein secretion in PTECs and that PTECs which were stably transfected and overexpressing hHGF abrogated the inflammatory reaction mediated by hypoxia/reoxygenation, being a suitable model for later studies.

Bone marrow transplantation induces normoglycemia in a type 2 diabetes mellitus murine model.

OBJECTIVE: To study the cellular mechanisms involved in the regression of diabetic nephropathy, bone marrow-derived cells must be identified. The aim of this study was to obtain a diabetic chimeric model with bone marrow cells expressing enhanced green fluorecence protein (EGFP), without modifying the course of diabetic nephropathy. MATERIALS AND METHODS: Bone marrow transplantation (BMT) was performed in an obese type 2 diabetic murine model (db/db) owing to a mutation in the leptin receptor gene. Whole bone marrow from female donor C57BL/6 EGFP+ mice was transplanted into 8-week-old C57BL/6 mice and into 8- and 24-week-old female C57BLKS (db/db) EGFP- mice. Recipient mice received total body irradiation (TBI) followed by bone marrow (BM) cell infusion. We tested various irradiation doses (Gy) and numbers of BM cells. RESULTS: When a low TBI dose and a small number of BM cells were administered, only syngeneic C57BL/6 mice became chimeric, whereas allogeneic db/db mice showed rejection. When Gy dose and BM cells were increased, db/db mice became chimeric. However, 8-week-old db/db mice lost the obese phenotype and became normoglycemic, probably due to peripheral BM cell infiltration. Conversely, 24-week-old db/db mice remained obese showing similar blood glucose values, body weights, albuminuria, and glomerular lesions at nontransplanted db/db mice. CONCLUSIONS: Recipient age greatly influenced the peripheral repopulation after BMT in db/db mice. Only the adult chimeric db/db mice seemed to be a good model to study the cellular mechanisms involved in the regression of diabetic nephropathy.

Immunephenotype of glomerular and interstitial infiltrating cells in protocol renal allograft biopsies and histological diagnosis.

Patients with a protocol renal allograft biopsy simultaneously displaying interstitial fibrosis/tubular atrophy (IF/TA) and subclinical rejection (SCR) have a shortened graft survival than patients with a normal biopsy, or with a biopsy only displaying IF/TA or SCR. The poor outcome of these patients could be related with a more severe inflammation. We evaluate the immunophenotype of infiltrating cells in these diagnostic categories. Nonexhausted paraffin blocks from protocol biopsies done during the first year were stained with anti-CD45, CD3, CD20, CD68 and CD15 monoclonal antibodies. Glomerular and interstitial positive cells were counted. C4d deposition in peritubular capillaries was evaluated. Histological diagnoses were: normal (n = 80), SCR (n = 17), IF/TA (n = 42) and IF/TA + SCR (n = 17). Only interstitial CD20 positive cells were significantly increased in patients displaying IF/TA + SCR; normal (137 +/- 117), SCR (202 +/- 145), IF/TA (208 +/- 151) and IF/TA + SCR (307 +/- 180 cells/mm(2)), p < 0.01. The proportion of biopsies displaying C4d deposition was not different among groups. The upper tertile of CD20 positive interstitial cells was associated with a decreased death-censored graft survival (relative risk: 3.01, 95% confidence interval: 1.23-7.35; p = 0.015). These data suggest that B-cell interstitial infiltrates are associated with histological damage and outcome, but do not distinguish whether these infiltrates were the cause or the consequence of chronic tubulo-interstitial damage.

Donor structural and functional parameters are independent predictors of renal function at 3 months.

INTRODUCTION: Epidemiological studies have shown that demographic, clinical, and histological donor characteristics influence renal function after transplantation, but whether these variables are independent predictors has not been established. The aim of this study was to evaluate the relative contribution of different donor variables on glomerular filtration rates (GFRs) at 3 months. PATIENTS AND METHODS: We analyzed single renal transplants performed at our center from January 2000 to July 2004. Donor variables included age, gender, weight and height, cause of death, duration of brain death, serum creatinine at admission and preprocurement, history of arterial hypertension or diabetes mellitus, and smoking habit. Donor chronic damage score was calculated in preimplantation biopsies as was the addition of interstitial fibrosis, fibrous intimal thickening, and glomerulosclerosis (<10% = 0, >10% = 1). Donor and recipient GFRs were calculated according to the Cockroft-Gault formula. RESULTS: We analyzed 202 transplants obtained from 113 deceased donors. A renal biopsy was available in 111 transplants. Recipient GFR at 3 months correlated negatively with donor age (R = -0.32, P < .01) and donor chronic damage score (R = 0.32, P < .01). GFR was lower among recipients of female versus male donors (50 +/- 15 vs 60 +/- 20 mL/min; P < .01). Donor cerebrovascular accident death (53 +/- 19 vs 63 +/- 19 mL/min; P < .01) and hypertension (48 +/- 16 vs 59 +/- 20 mL/min; P < .01) were also associated with lower GFR at 3 months. There was a positive correlation between GFR at admission, GFR preprocurement, and GFR at 3 months (R = 0.32 and R = 0.18 respectively; P < .01). Stepwise regression analysis included chronic damage score, GFR at admission, and donor gender but not donor age as independent predictors of GFR at 3 months (R = 0.50; P < .01). CONCLUSION: Donor structural and functional parameters are independent predictors of renal function at 3 months.

Preliminary results of treatment with pegylated interferon alpha 2A for chronic hepatitis C virus in kidney transplant candidates on hemodialysis.

INTRODUCTION: At present, there is little published information on the outcome of treatment with pegylated interferon (Peg-IF alpha 2a) in hepatitis C virus (HCV)-infected hemodialysis patients awaiting renal transplantation. The objective of this study was to assess the efficacy and tolerance of Peg-IF alpha 2a in this population. PATIENTS AND METHODS: Twelve noncirrhotic HCV-infected patients (10 men, 50 +/- 8 years of age, genotype 1b 84%), were prescribed Peg-IF alpha 2a, at 135 microg/wk for 48 weeks. Liver biopsy was performed in 11 of 12 cases. RESULTS: Six patients completed 48 weeks of treatment, with one end of treatment response (ETR), two sustained viral responses (SVRs), and three HCV relapses. Treatment was shorter in the six remaining patients: two cases 24 weeks (one due to medical reasons with relapse, one due to nonresponse), one patient chose to discontinue at 14 weeks (with relapse), one patient died of stroke at 10 weeks, and in two additional patients interferon was withdrawn at 18 weeks because of severe anemia (SVR) and at 26 weeks due to prolonged fever (relapse). Other secondary treatment-related events included anemia (requiring transfusion in two patients and major erythropoietin administration in six), and fever in four patients. CONCLUSIONS: Peg-IF had limited efficacy in this group, with ETR in 83%, SVR in only 25%, and recurrence in 50%. Tolerance was moderate, with 4/12 (33%) discontinuing treatment due to adverse events, personal decision, or death. Large randomized controlled studies are needed to determine the role of Peg-IF treatment in this population.

Mycophenolate mofetil and sirolimus combination in renal transplantation.

Mycophenolate mofetil (MMF) and sirolimus (SRL) are potent non-nephrotoxic xenobiotic immunosuppressants. Their complementary properties may provide the rationale for their combination in induction and maintenance regimens. MMF, a reversible inhibitor of inosin monophosphate dehydrogenase (IMPDH) acts as an antiproliferative drug; and SRL, an mTOR (mammalian target of rapamycin) inhibitor, inhibits cell proliferation driven by growth factors. Early experiences with the use of the SRL, MMF and steroid combination yielded insufficient prophylaxis of acute rejection. However, the introduction of induction therapy with mono- or polyclonal antilymphocyte antibodies to the SRL-MMF and steroid combination brings an efficient acute rejection prophylaxis, while improving renal function and/or reducing of chronic allograft nephropathy (CAN). However, adverse events related to the use of this drug combination (mainly haematological and surgery-related) result in a high rate of discontinuations in some trials, which may hamper the potential benefits of this calcineurin-inhibitor (CNI)-free strategy. Also, currently under investigation is whether in long-term immunosuppression, in MMF-treated patients, CNIs can be replaced by SRL to avoid and/or halt progression of chronic nephropathy and to improve graft survival. However, some authors reported a high proportion of patients with oral ulcers and proteinuria after switching to SRL. In short, refining the use of MMF and SRL may provide a better risk/benefit ratio to pave the way towards non-nephrotoxic immunosuppression.

Subclinical rejection impairs glomerular adaptation after renal transplantation.

After transplantation, glomerular volumes increases and large glomerular volume at 4 months is associated with better renal function. The aim is to characterize glomerular adaptation after the fourth month in two serial protocol biopsies and its relationship with subclinical rejection and chronic allograft nephropathy (CAN). Mean glomerular volume (Vg) was estimated according to the Weibel and Gomez method in a 4-month and 1-year serial protocol biopsies in 61 stable grafts. Glomerular enlargement (deltaVg) was calculated as the Vg difference between both biopsies. Banff schema was used to evaluate renal biopsies. Vg increased from 4.4+/-2.4 to 5.7+/-2.6 x 10(6) microm3 (P<0.001). Mean deltaVg was 1.0 x 10(6) microm3. Patients with deltaVg<1 were considered as patients with impaired glomerular enlargement (n=29). Impaired glomerular enlargement was associated with increased acute index score in the 4-month (1.83+/-1.56 vs 1.06+/-1.48; P<0.05) and 1-year protocol biopsies (1.52+/-1.59 vs 0.62+/-1.07; P<0.05). Impaired glomerular enlargement was also associated with increased progression of chronic lesions between the 4-month and 1-year biopsy in the glomerular (0.17+/-0.38 vs 0.55+/-0.63; P<0.01), tubular (0.38+/-0.56 vs 0.83+/-0.85; P<0.01), and interstitial compartment (0.41+/-0.57 vs 0.90+/-0.86; P<0.01). The proportion of sclerotic glomeruli between both biopsies increased in patients with impaired glomerular enlargement (1.5+/-3.9 to 5.3+/-10.1, P<0.05) while it did not modify in patients with glomerular enlargement (2.1+/-7.3 vs 2.6+/-4.5; P=NS). During the first year, glomeruli enlarge but this adaptation mechanism is impaired in patients with subclinical rejection. Moreover, impaired glomerular enlargement is associated with progression of CAN.

HGF gene therapy attenuates renal allograft scarring by preventing the profibrotic inflammatory-induced mechanisms.

Inflammatory processes and tissue scarring are characteristic features of chronic allograft nephropathy. Hepatocyte growth factor (HGF) has beneficial effects on renal fibrosis and it also ameliorates renal interstitial inflammation as it has been recently described. Contrarily to protein administration, intramuscular gene electrotransfer allows sustained release of HGF. So, here we hypothesized that gene therapy with human HGF would diminish the characteristic scarring of chronic allograft nephropathy either by antagonizing tissue fibrosis mechanisms or by reducing inflammation. Lewis rats transplanted with cold preserved Fischer kidneys received vehicle (NoHGF) or intramuscular plasmid DNA encoding HGF plus electroporation either before transplantation (IniHGF, early post-transplant cytoprotection of tubular cells) or 8/10 weeks after transplantation (DelHGF, delayed prevention of chronic mechanisms). Serum creatinine and proteinuria were measured every 4 weeks for 24 weeks. Grafts at 12 or 24 weeks were evaluated for glomerulosclerosis, fibrosis inflammatory cells and mediators, cell regeneration and tubulo-interstitial damage. Nontreated animals developed renal insufficiency, progressive proteinuria and fibrosis among other characteristic histological features of chronic allograft nephropathy. Treatment with human HGF, especially when delayed until the onset of fibrogenic mechanisms, reduced renal failure and mortality, diminished tubule-interstitial damage, induced cell regeneration, decreased inflammation, NF-kappaB activation, and profibrotic markers at 12 weeks and prevented late interstitial fibrosis and glomerulosclerosis. The effectiveness of HGF-gene therapy in the prevention of renal allograft scarring is related with the halt of profibrotic inflammatory-induced mechanisms.

Subclinical rejection associated with chronic allograft nephropathy in protocol biopsies as a risk factor for late graft loss.

Chronic allograft nephropathy (CAN) in protocol biopsies is associated with graft loss while the association between subclinical rejection (SCR) and outcome has yielded contradictory results. We analyze the predictive value of SCR and/or CAN in protocol biopsies on death-censored graft survival. Since 1988, a protocol biopsy was done during the first 6 months in stable grafts with serum creatinine <300 micromol/L and proteinuria <1 g/day. Biopsies were evaluated according to Banff criteria. Borderline changes and acute rejection were grouped as SCR. CAN was defined as presence of interstitial fibrosis and tubular atrophy. Mean follow-up was 91 +/- 46 months. Sufficient tissue was obtained in 435 transplants. Biopsies were classified as normal (n = 186), SCR (n = 74), CAN (n = 110) and SCR with CAN (n = 65). Presence of SCR with CAN was associated with old donors, percentage of panel reactive antibodies and presence of acute rejection before protocol biopsy. Cox regression analysis showed that SCR with CAN (relative risk [RR]: 1.86, 95% confidence interval [CI]: 1.11-3.12; p = 0.02) and hepatitis C virus (RR: 2.27, 95% CI: 1.38-3.75; p = 0.01) were independent predictors of graft survival. In protocol biopsies, the detrimental effect of interstitial fibrosis/tubular atrophy on long-term graft survival is modulated by SCR.

Long-term effect of hepatitis C virus chronic infection on patient and renal graft survival.

BACKGROUND: Hepatitis C virus (HCV) infection increases morbimortality in renal transplantation. The immune response against the HVC is not predictable in a great proportion of patients developing into chronic liver disease, glomerulonephritis, or both. PATIENTS: We analyzed the impact of posttransplant chronic hepatitis development on patient and graft survival in 200 HCV-positive/HBsAg-negative renal allograft recipients transplanted between 1981 and 2003. RESULTS: Ninety-eight patients developed chronic ALT elevation (ALT+), while 102 did not (ALT-). There was no difference in acute rejection episodes (ARE), acute tubular necrosis, donor and recipient age, gender, HLA mismatches, and number of previous renal transplants. Development of ALT+ was associated with a worse patient survival (90% vs 65% at 15 years of follow-up, P = .007; RR = 3.8, CI = 1.4-10.1), an effect that was independent of other variables as time on dialysis and age. The main causes of death among ALT+ were chronic liver disease (52%), cardiovascular (26%), and infection (13%), whereas in ALT- they were cardiovascular (33%), cancer (33%), and chronic liver disease (16%). Conversely, graft survival (censoring for patient death with a functioning graft) was higher among ALT+ (50% vs 35% at 15 years of follow-up, P = .04; RR = 1.5, CI = 1.19-2.22). Causes of graft loss in ALT- patients were chronic allograft nephropathy (CAN, 53%), glomerulonephritis (GN, 18%), acute rejection episode (AR, 22%), and death (5%), whereas among ALT+ they were CAN (36%), GN (31%), ARE (10%), and death (21%; P = .01). By multivariate analysis, ALT- (RR = 1.6, CI = 1.07-2.55, P = .02) and de novo GN (RR = 2, CI = 1.29-3.09, P = .002) were associated with worse renal allograft survival. CONCLUSION: Our results suggested that a better immune response against the HCV lead to greater patient survival but poorer graft survival.

Cyclosporine nephrotoxicity.

The polypeptide immunosuppressant cyclosporine is a prodrug that binds an intracellular immunophilin. The complex cyclosporine-cyclophilin binds and inhibits the phosphatase activity of calcineurin interfering with the dephosphorilation of members of the nuclear factor of activated T cells, which is involved in the regulation of genes encoding many cytokines. However, calcineurin is not exclusive from T cells; it is also present in many organs, such as the kidney, and their inhibition accounts for both the immunosuppressive and the nephrotoxic effects of cyclosporine. In renal transplantation, it was shown that graft survival improved progressively between 1998 to 1996, mainly due to reduction of acute rejection episodes. There is no doubt that cyclosporine contributed to that success. After 20 years, cyclosporine targets for maintenance immunosuppression have not been defined and the magnitude of chronic cyclosporine nephrotoxicity in renal allografts is not known, in part by the limitations of histologic classification of chronic allograft nephropathy. In the future, the new technology based on DNA microarrays can be a valuable tool to separate chronic drug toxicity from other causes of graft deterioration. On the other hand, in the cyclosporine era, chronic renal failure has emerged as a frequent adverse event after transplantation of nonrenal organs and it is associated with increased risk of death. Although there is not yet enough evidence to support a generalization of calcineurin-free immunosuppression, we should open our minds to the upcoming new concepts on immunosuppression.