Transplant vasculopathy in early protocol renal allograft biopsies.
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Biomedical subjects
Publications and source records attributed to F Moreso.
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BACKGROUND: Transplant recipients of kidneys harvested from old donors have a high incidence of delayed graft function (DGF) and a poor graft outcome. This result is partly explained by the increased incidence of acute rejection in patients suffering from DGF. However, the long-term impact of donor age and DGF in rejection free renal transplants is not well established. The aim of the present work is to evaluate the impact of donor age and DGF on long-term outcome in renal transplants with or without acute rejection. PATIENTS: We review all cadaveric kidney transplants performed in our centre between April 1984 and December 1995 treated with a cyclosporin-based immunosuppression. RESULTS: Five hundred and ninety-five patients were included. The overall incidence of DGF was 29.1%, and this event was associated with an increased donor age and cold ischaemia time. Univariate and multivariate analysis showed that graft loss was associated with acute rejection (relative risk (RR) 2.24, 95% confidence interval (CI) 1.62-3.01); DGF (RR 1.83, 95% CI 1.32-2.54); donors >50 years (RR 1.65, 95% CI 1.13-2.38); and retransplantation (RR 1.52, 95% CI 1.01-2.31). In rejection-free patients there were two independent predictors of graft failure: donor >50 years (RR 2.40, 95% CI 1.45-4.01); and DGF (RR 2.42, 95% CI 1.53-3.84). CONCLUSIONS: Regardless of the presence of acute rejection, delayed graft function amplifies the detrimental effect of advanced donor age on long-term graft outcome.
BACKGROUND: Because of the shortage of kidneys available for transplantation, we began in 1985 to harvest kidneys from non-heartbeating (NHB) donors. METHODS: We compared the results of a group of 66 kidney recipients from NHB donors (NHB group) with 122 kidney recipients from heartbeating donors (HB group). We analyzed, in the NHB group, the influence of ischemia times in graft survival and we tested the best cut-offs by receiver operating characteristic curves. We also studied, using a univariate and multivariate Cox hazard model, the capacity of different variables to predict graft loss. RESULTS: Patient and graft survival were similar in both groups during the follow-up. The percentage of delayed graft function was the only significant difference between both groups (NHB group 62% vs. HB group 32%; P=0.0001). Delayed graft function, in the NHB group, is influenced by the warm ischemia time, which is directly related to the number of days to achieve a serum creatinine<300 mmol/L (P=0.0001). The best cut-off times in this group were 45 min for warm ischemia time and 22 hr for cold ischemia time. Recipients have a greater likelihood of losing the graft beyond those limits (P=0.017, relative risk: 7.3). The incidence of acute rejection was similar in both groups, and it was the only predictor factor of graft loss in the complete series of patients (P=0.0001), in the NHB group (P=0.007), and in the HB group (P=0.02). CONCLUSIONS: Reducing the incidence of acute rejection and shortening ischemia time are conditions needed to guarantee a long graft survival of kidneys from NHB donors.
BACKGROUND: The aim of the present study was to analyze whether minor differences in recipient body surface area have any predictive value on renal allograft evolution. METHODS: For this study, we considered 236 pairs of recipients who received a kidney from the same donor at our center between March 1985 and December 1995. Pairs in whom at least one patient presented any of the following events were excluded: graft loss during the first year of follow-up, diabetes mellitus, noncompliance with treatment, chronic pyelonephritis, and recurrent or de novo glomerulonephritis. Recipients of each pair were classified as large or small according to their body surface area (BSA). The percentage difference of BSA in each pair was calculated, and two cohorts of pairs were defined: BSA difference < or = 10% (n=76 pairs) and BSA difference >10% (n=70 pairs). RESULTS: The large recipients of the cohort with a BSA difference >10% showed a higher incidence of posttransplant delayed graft function (22/70 vs. 12/70, P=0.075), hypertension at 1 year of follow-up (51/70 vs. 35/70, P=0.006), and a higher serum creatinine level at 1-year follow-up (173 vs. 142 micromol/L, P=0.003), whereas in the cohort with a BSA difference < or = 10%, posttransplant evolution in large and small recipients was not different. Multivariate analysis showed that recipient BSA was an independent predictor of delayed graft function, posttransplant hypertension, and serum creatinine at 1-year follow-up. CONCLUSIONS: Relatively small differences in recipient BSA influence renal allograft evolution. Consequently, our data support that recipient size should be taken into consideration for renal allograft allocation.
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BACKGROUND: In renal transplantation the beneficial immunosuppressive effects of cyclosporin (CsA) may be curtailed by its nephrotoxicity, specially in patients receiving a cadaveric allograft from suboptimal donors or at risk of delayed graft function. Mycophenolate mofetil (MMF) and antithymocyte globulin (ATG) have each demonstrated to be potent immunosuppressants in renal transplantation. In a prospective analysis we have studied the results at 6 months of the combination of MMF, ATG and low-dose steroids in patients with low immunological risk receiving a first cadaveric renal allograft from a suboptimal donor or at risk of delayed graft function. METHODS: Patients with preformed reactive antibodies < 500% receiving a first graft from a suboptimal donor (age > or = 40 years, non-heart-beating, acute renal failure, arterial hypertension) or at risk of delayed graft function (cold ischaemia time > or = 24 h) were eligible for this open single-arm pilot trial. From September 1996 to March 1997 we recruited 17 patients. They were treated with MMF 2 g p.o. preoperatively, and after transplantation at 3 g/day; rabbit ATG i.v. at 2 mg/kg preoperatively, and 1.5 mg/kg/day the first day after transplantation, followed by four doses of 1 mg/kg on alternate days; prednisone was given at 0.25 mg/kg/day and reduced progressively to 0.1 mg/kg/day at 3 months. Primary outcomes were incidence of biopsy-proven acute rejection, delayed graft function, opportunistic infections, graft and patient survival, and the need for introduction of CsA treatment. RESULTS: delayed graft function occurred in two cases (12%). Four of 17 patients (24%) had a biopsy-proven acute rejection (2 grade I and 2 grade II) within the first 3 months after transplantation. CsA was added in two cases with grade II biopsy-proven acute rejection, and in one with grade I biopsy-proven acute rejection. In one patient MMF was replaced by CsA because of gastrointestinal intolerance. Mean serum creatinine 6 months after transplantation was 159+/-59 micromol/1. Cytomegalovirus tissue invasive disease occurred in one patient (6%). At 6 months follow-up all patients are alive with functioning allografts. CONCLUSIONS: These preliminary results suggest that in low-immunological-risk patients who receive a suboptimal renal allograft or at risk of delayed graft function, the combination of MMF, ATG, and steroids is an efficient immunosuppressive regime that may avoid the use of CsA in 70% of the recipients.
Mycophenolate mofetil (MMF) combined with conventional cyclosporine and steroids doses efficiently prevents acute rejection in kidney transplants. However, this regimen has been associated with an increased incidence of cytomegalovirus (CMV) disease and leukopenia, specially in patients receiving MMF at 3 g/d, suggesting that the combination of two powerful immunosuppressants carries the risk of overimmunosuppression. For this reason, we treated a group of patients with MMF 3 g/d combined with low cyclosporine and steroids doses. Eighty-two kidney transplants performed at two centers and enrolled in the European Mycophenolate Mofetil Cooperative Study were randomized to receive: A) placebo (n = 27); B) MMF 2 g/d (n = 27); and C) MMF 3 g/d (n = 28). In this double blind study all patients received cyclosporine and steroids at conventional doses. Fifteen kidney transplants enrolled in an MMF open pharmacokinetic study were treated with MMF 3 g/day combined with low cyclosporine and steroid doses (group D). Efficacy was evaluated as the incidence of biopsy proven acute rejection, and safety focused on CMV disease and leukopenia. Patients receiving MMF showed a low incidence of biopsy proven rejection (B) 18.5%; C) 10.7%; and D) 13.3%). Patients of group C had a high incidence of CMV disease (35.7%) when compared with the other groups (lower than 8%). Incidence of leukopenia was higher in patients treated with MMF (B) 25.9%; C) 39.3%; and D) 40%) than in placebo treated patients (7.4%). Patients in group (C) displayed leukopenia mainly in the context of CMV disease, while patients of group (D) had leukopenia not related to CMV infection. All patients of group (D) who presented leukopenia recovered after MMF reduction dose, while in group (C) there were 5 out of 28 patients who required MMF withdrawal. We propose that a reasonable approach to take advantage of a powerful non-nephrotoxic immunosuppressant such as MMF, could be the administration of this drug at 3 g/d from the time of transplantation combined with low CsA and steroid doses.
BACKGROUND: Acute rejection is an inherent risk of the withdrawal of steroids in renal allograft recipients. Mycophenolate mofetil is a potent immunosuppressant that, when given with cyclosporine (CsA), reduces the incidence of acute rejection and may facilitate discontinuation of steroids without increasing the risk of rejection. METHODS: In an open pilot study, steroids were withdrawn from 26 adult cadaveric kidney transplant recipients. Corticosteroids were discontinued between 4 and 30 (mean 17) months after transplantation, and steroid-free follow-up ranged from 7 to 18 (mean 10) months. RESULTS: Mean CsA doses, CsA blood levels, and serum creatinine at the time of steroid withdrawal and at last patient visit after cessation of steroids were 4.2+/-1.2 mg/kg/day and 3+/-0.8 mg/kg/day (P<0.001), 170+/-53 ng/ml and 113+/-34 ng/ml (P<0.001), and 133+/-36 microM/L and 130+/-37 microM/L (NS), respectively. No rejection episodes occurred after steroid withdrawal. CONCLUSIONS: This open study shows that corticosteroids can be safely and successfully withdrawn from renal allograft recipients receiving CsA and mycophenolate mofetil.
To evaluate whether biopsies performed early after transplantation in stable grafts can predict graft failure due to chronic transplant nephropathy, a protocol biopsy was performed at three months in 98 patients treated with antilymphocytic antibodies, cyclosporine and prednisone. Patients were followed for 58 +/- 16 months. Histological diagnosis according to the Banff schema were: normal (N = 41), borderline changes (N = 12), chronic transplant nephropathy (CTN; N = 30), CTN associated to borderline changes (N = 11) and acute rejection (N = 4). Biopsies displaying acute rejection were not considered for statistical analysis. Since clinical characteristics of patients displaying CTN either with or without tubulitis were not different, biopsies were grouped as presence or absence of CTN. Patients displaying CTN had an increased incidence of acute rejection before performing biopsy (24.3 vs. 3.9%, P = 0.003), a higher mean cyclosporine level until biopsy (242 +/- 74 vs. 214 +/- 59 ng/ml, P = 0.049) and a lower actuarial graft survival (80.5% vs. 94.4%, P = 0.024). We conclude that early protocol biopsies are useful to detect patients at risk of losing their graft due to chronic transplant nephropathy.
OBJECTIVE: To segment renal interstitial space in order to automatically quantify renal cortical interstitial volume fraction (Vvint/cortex) by means of image analysis techniques. STUDY DESIGN: The study group consisted of 35 renal biopsies with different degrees of chronic interstitial damage. Biopsies were stained with Sirius red and digitized under polarized light. Two methods were employed to segment interstitial space: (1) interstitial bright particles were thresholded, and afterwards interstitial space was reconstructed with a morphologic operation, and (2) the texture of the surroundings of each pixel was quantified by means of local granulometry, and this information was employed as the input of a neural network in order to classify interstitial and tubular pixels. RESULTS: The correlation between Vvint/cortex obtained manually and both methods was r = .92. The first method produced some deformation of tubular contours and underestimated Vvint/cortex (beta = .70) when compared to the second approach (beta = .95) (P < .05). CONCLUSION: Two different algorithms based on image analysis techniques allow the classification of renal interstitial and tubular structures and consequently allow the automated and precise estimation of renal Vvint/cortex.
The extraction of circulating antiglomerular basement membrane (GBM) antibodies by plasmapheresis (PP) has allowed the prognosis of Goodpasture's disease to markedly improve. Immunoabsorption (IA) may improve the results of PP upon allowing more effective immunoglobulin extraction. Two patients with Goodpasture disease were treated with IA. A rapid decrease was observed in the serum levels of anti GBM antibodies and improvement in respiratory failure. In one of the patients this regimen was administered following the observation of a lack of clinical response of pulmonary hemorrhage in three PP sessions (9 liters of treated plasma). In this patient, the IA processed 39 liters of plasma and the method was found to be equally effective on reinstatement (29 liters) on the occasion of a relapse in the pulmonary symptoms presented at three weeks after the first treatment. Both cases showed renal involvement. In one case this was incipient and the treatment was associated with non progression of the kidney disease, normalization of the urine sediment and preservation of renal function. In the second case treatment was initiated at an advanced disease state with no changes in dialysis needs. Immunoadsorption has shown to be effective in the treatment of pulmonary hemorrhage in Goodpasture's disease. Onset of treatment at an early stage of the kidney disease may avoid progression to renal failure.
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There is a relationship between chronic renal damage and renal function at the time of biopsy. Since the quantification of interstitial lesions with morphometric techniques is very time consuming, a fully automatic method to quantify chronic damage is desirable. Progression of chronic renal damage could be viewed as a texture modification of tubulointerstitial structures. The aim of the present work is to study whether chronic renal damage could be automatically measured by means of texture analysis based on mathematical morphology. Among the morphological tools the best suited for our purpose is that of granulometry. Between four and six fields from 35 renal biopsies with different degrees of renal damage were stained with Sirius red and digitized under polarized light. In each field granulometric function with a circular structuring element was obtained. Interstitial volume fraction was measured with a point counting technique. Glomerular filtration rate at the time of biopsy was available in each case. A positive relationship between granulometric function and glomerular filtration rate was observed (r2 = 0.85). The determination coefficient between interstitial volume fraction and renal function was (r2 = 0.54). In conclusion, we describe a fully automatic method that precisely quantifies interstitial chronic renal damage.