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Biomedical subjects

J M Cruzado

Publications and source records attributed to J M Cruzado.

At least 37 records · Page 2Linked to original sources
PubMed2001

Hepatitis C virus infection and de novo glomerular lesions in renal allografts.

In the present study we examine whether hepatitis C virus (HCV) infection status influences glomerular pathologic findings in renal allografts and its effect on graft outcome. Renal allograft biopsies performed between January 1991 and June 1999 were considered. Exclusion criteria were insufficient sample, unknown HCV serological status at time of biopsy and final diagnosis of acute rejection. Light microscopy and immunofluorescence studies were performed on all biopsies. According to a predefined protocol, electron microscopy was carried out. Of 138 eligible renal allograft biopsies, 42 fulfilled at least one exclusion criterion. Of 96 biopsies selected for the study, 44 (45.8%) were from HCV-positive and 52 from HCV-negative recipients. Renal biopsy was performed 74 +/- 55 and 60 +/- 39 months after transplantation in HCV-positive and HCV-negative groups, respectively (p = 0.12). Of 44 HCV-positive biopsies, 20 (45.4%) showed membranoproliferative glomerulonephritis (MPGN) (16 type I and 4 type III). Conversely, in HCV-negative biopsies there were only three cases of MPGN (2 type I and 1 type III). De novo membranous GN (MGN) was diagnosed in 8/44 (18.2%) HCV-positive and in 4/52 (7.7%) HCV-negative cases. The prevalence of chronic transplant glomerulopathy was similar in HCV-positive and HCV-negative groups (11.4% and 11.5%, respectively). The prognosis of de novo GN (either MPGN or MGN) was worse in HCV-positive than in HCV-negative recipients (relative risk 4.89; 95% confidence interval, 1.15-20.69; p = 0.03). By multivariate analysis, HCV-positive serology infection was the only independent predictor of graft loss (relative risk 2.64; 95% confidence interval, 1.35-5.17; p = 0.005). In diagnostic renal allograft biopsies the presence of de novo immune-mediated glomerulonephritis, especially type I MPGN, is strongly associated with HCV infection and results in accelerated loss of the graft.

Adult↗
PubMed2000

Cold ischemia in the absence of alloreactivity induces chronic transplant nephropathy through a process mediated by the platelet-activating factor.

BACKGROUND: Ischemia-reperfusion injury is considered a risk factor for the development of chronic transplant nephropathy (CTN) although the mechanisms that mediate its effects have not been completely established. We have previously shown that treatment with a platelet-activating factor (PAF) receptor antagonist (UR12670) protected kidneys from the progression to chronic nephropathy induced by warm ischemia. Here we examine the contribution of cold ischemia to the development of late functional and structural kidney changes in rats subjected to syngeneic renal transplantation and the role of PAF in this chronic nephropathy. SUBJECTS AND METHODS: Lewis rats were used as kidney donors and recipients, which were transplanted either immediately or after a cold ischemia period of 5 hr. Contralateral nephrectomy was performed on the seventh day after transplantation. Cyclosporine was administered for 15 days after transplantation. Groups were as follows: Sy, immediate transplantation; SyI, transplantation after 5 hr of cold ischemia; SyIUr, transplantation after 5 hr of cold ischemia plus UR12670 from the transplantation day to the end of the study, at 24 weeks. Serum creatinine, creatinine clearance, and proteinuria were determined every 4 weeks. Urinary

Animals↗
PubMed2000

Influence of nephron mass in development of chronic renal failure after prolonged warm renal ischemia.

The present study examined the long-term consequences of warm renal ischemia (WRI) with or without renal ablation. Male Sprague-Dawley rats (250-300 g) were subjected to 60 min of complete WRI by pedicle clamping and then followed for 52 wk. Animals were organized into four groups: rats in which both kidneys were subjected to warm ischemia (2WIK); rats with left WRI and right nephrectomy (1WIK); uninephrectomized rats with a left nonischemic kidney (1NK); and sham-operated rats (2NK). Additional animals were studied at 24 h, 7 days, and 16 and 32 wk. In the first week after WRI, rats from the 2WIK and 1WIK groups displayed a similar degree of acute renal damage. After recovering from acute renal failure, 1WIK rats developed progressive and severe proteinuria, whereas it was mild in the 2WIK group, as well as in the 1NK and 2NK groups. Only animals from the 1WIK group developed severe chronic renal failure, glomerulosclerosis, interstitial fibrosis, and upregulation of transforming growth factor-beta(1) (TGF-beta(1)) gene, which was associated with increased TGF-beta(1) protein expression in tubular epithelial cells, arterioles, and in areas of mononuclear interstitial cell infiltrate. On the contrary, long-term renal TGF-beta(1) expression, function, and histology were similar in 2WIK and 2NK rats. The present study shows that prolonged bilateral WRI, when both kidneys are retained in place, induces very mild long-term renal lesions as opposed to the severe renal scarring observed when WRI is combined with contralateral nephrectomy.

Acute Kidney Injury↗
PubMed1999

Long-term protective effect of UR-12670 after warm renal ischemia in uninephrectomized rats.

BACKGROUND: The phospholipid platelet-activating factor (PAF) participates in the pathogenesis of renal ischemia/reperfusion injury, and in vitro, it induces synthesis of extracellular matrix proteins by mesangial and tubular epithelial cells. This study investigated the long-term effects of the potent orally active PAF antagonist UR-12670 in warm ischemic uninephrectomized rats, which was given according to different therapeutic schedules. METHODS: Uninephrectomized male Sprague-Dawley rats were divided into five groups and were followed for 52 weeks: rats without ischemia (SK); ischemic kidney for 60 minutes (SIK); ischemic kidney and UR-12670 from 0 to the 7th day (UR 0-7); ischemic kidney and UR-12670 from day 0 to 52 weeks (UR 0-E); and ischemic kidney and UR-12670 from day 8 to week 52 (UR 8-E). Two more groups (ischemic and UR treated) served to evaluate the UR-12670-protective effect on ischemic acute renal failure at one week. RESULTS: UR-12670 administration exerted functional and morphological protection against post-ischemic acute renal failure. The ischemic untreated (SIK) group developed progressive proteinuria from week 12. The onset of proteinuria in ischemic UR-12670-treated groups was delayed to the 24th week, and it was significantly lower than in SIK group throughout the study. Only SIK and ischemic-treated UR 0-7 rats presented with chronic renal failure, as shown by creatinine, creatinine clearance, glomerular filtration rate (GFR), and renal plasma flow (GFR 52 weeks: SK, 2525 +/- 267; SIK, 992 +/- 149; UR 0-7, 1551 +/- 385 microliter/min). Kidneys from the short-term treated group (UR 0-7) showed a reduction of glomerulosclerosis (SK, 14.4 +/- 3.7; SIK, 75.7 +/- 7.7; UR 0-7, 41. 5 +/- 8.5%) and vascular myointimal hyperplasia, but the tubulointerstitial damage (tubulointerstitial score: SK, 0.2 +/- 0. 2; SIK, 4.4 +/- 0.5; UR 0-7, 3.7 +/- 0.7) was similar to that in the ischemic untreated group. Long-term ischemic treated rats (UR 0-E, UR 8-E) did not develop chronic renal failure (GFR: UR 0-E, 2059 +/- 314; UR 8-E, 2410 +/- 208 microliter/min). In these groups, glomerulosclerosis (UR 0-E, 32.8 +/- 5.8; UR 8-E, 24.3 +/- 3.0%), tubulointerstitial damage (tubulointerstitial score: UR 0-E, 2.1 +/- 0.5; UR 8-E, 1.9 +/- 0.3) and vascular myointimal hyperplasia were significantly lower than in the ischemic untreated group. By in situ hybridization, an increase of transforming growth factor-beta1 mRNA expression in glomerular and tubular cells was observed in ischemic untreated and ischemic treated UR 0-7 rats. UR-12670 long-term treated rats showed a clear reduction of transforming growth factor-beta1 mRNA-positive glomerular cells. CONCLUSION: The chronic administration of the PAF antagonist UR-12670 attenuates the long-term effects of ischemia-reperfusion injury in uninephrectomized rats. The beneficial effect of this agent, even when given beyond the initial ischemia/reperfusion injury, suggests that PAF plays a role in the mechanisms of progression to late renal damage in this model.

Acute Kidney Injury↗
PubMed1999

Prevention of cold ischaemia-reperfusion injury by an endothelin receptor antagonist in experimental renal transplantation.

BACKGROUND: Endothelin (ET) is known to play a role in the pathogenesis of warm ischaemic renal damage, however, little is known about its involvement in renal cold ischaemia. This study was designed to investigate the response of ET after kidney cold ischaemia, and to assess the potential protective effect of bosentan, a dual, non-selective ET(A)/ET(B) receptor antagonist, against cold ischaemia reperfusion injury in a rat model of syngeneic renal transplantation. METHODS: Kidneys from Lewis rats were transplanted, either immediately or after 5 h of cold preservation. After 48 h, contralateral nephrectomy was performed. Rats were organized into three groups: Tr-NoISC, no cold ischaemia; Tr-ISC, 5 h cold ischaemia; and Tr-BOS, 5 h cold ischaemia plus bosentan (100 mg/kg/day, from the day before transplantation until the seventh day post-transplantation). On day 7, plasma and tissue immunoreactive ET (irET), as well as ET mRNA tissue expression, were evaluated. Renal function was measured by means of serum creatinine on days 3, 4, 5 and 7, and by creatinine clearance on day 7. Conventional histology was performed. RESULTS: The ischaemic group had significantly higher plasma irET levels than the non-ischaemic group and significantly lower levels than the bosentan group. Tissue irET levels and ET mRNA expression were similar in the ischaemic and bosentan groups and were higher than in the non-ischaemic group. Throughout the follow-up, serum creatinine was significantly higher in the ischaemic group than in the bosentan group. Moreover, creatinine decreased rapidly in the bosentan group after nephrectomy, whereas it continued to increase for 48 h in the ischaemic group. Kidneys from the ischaemic group showed a higher degree of tubular-cell necrosis and epithelial-cell detachment than kidneys from the bosentan group. CONCLUSIONS: We conclude that cold ischaemia and preservation damage induces an increase in renal ET mRNA and irET expression in the reperfusion phase, contributing both to the deterioration of renal function and to tubular necrosis. Bosentan is effective in protecting kidneys from this cold ischaemia reperfusion damage. Non-selective ET(A)/ET(B) receptor antagonists might be potentially useful in clinical renal transplantation.

Animals↗
PubMed1998

Effect of a platelet-activating factor (PAF) receptor antagonist on hyperacute xenograft rejection; evaluation in a pig kidney-human blood xenoperfusion model.

In pig to human discordant xenotransplantation, PAF may contribute to the pathogenesis of hyperacute xenograft rejection (HXR). We examined the release of PAF and the effect of a PAF receptor antagonist (BN 52021) on HXR in a pig kidney-human blood xenoperfusion model. Pig kidneys were perfused with porcine blood (AUTO group, n = 5), human blood (HETER group, n = 6) or human blood plus BN 52021 (BN group, n = 4), respectively. In contrast to HETER kidneys that never produced urine and were rejected in 15-30 min, the administration of BN 52021 induced a partial recovery of glomerular filtration rate and allowed kidneys to function until the end of the study. The release of PAF and soluble P-selectin, as well as endothelial P-selectin expression and tissue myeloperoxidase (MPO), were much higher in the HETER than in the AUTO group. HETER and BN kidneys displayed similar natural xenoantibody titres, CH50, PAF, soluble P-selectin as well as renal immunoglobulin (IgM, IgG, IgA) and complement (C3, C1q) deposition. However, HETER kidneys displayed a full histologic picture of HXR (mainly interstitial haemorrhage and vascular microthrombi) and BN kidneys had only endothelial cell swelling. Also, BN 52021 administration attenuated glomerular and vascular P-selectin expression and renal tissue MPO activity. We conclude that in the pig kidney-human blood xenoperfusion model, PAF is produced in higher amounts than in the pig kidney-pig blood autologous combination. The administration of BN 52021 exerts a protective effect by means of attenuating the acute inflammatory response and blocking vascular microthrombi formation.

Animals↗
PubMed1998

Primary immunosuppression with mycophenolate mofetil and antithymocyte globulin for kidney transplant recipients of a suboptimal graft.

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.

Adult↗
PubMed1998

Incidence of leukopenia and cytomegalovirus disease in kidney transplants treated with mycophenolate mofetil combined with low cyclosporine and steroid doses.

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.

Adult↗
PubMed1997

Steroid withdrawal in mycophenolate mofetil-treated renal allograft recipients.

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.

Acute Disease↗
PubMed1997

Changes in serum osteocalcin levels in the follow-up of kidney transplantation.

Serum osteocalcin, total alkaline phosphatase, intact parathyroid hormone (PTH), creatinine, calcium, and phosphate were determined in 23 kidney cadaveric allograft recipients, immediately before and 0.5, 1, 3 and 6 months after surgery. Immunosuppressive treatment was based on low doses of corticosteroids and cyclosporin combined with antilymphoblast globulin. The decrease in serum creatinine was accompanied by falling PTH concentrations. Serum osteocalcin levels were higher than normal before kidney transplantation and diminished at 0.5 and 1 month after surgery. Significant increases in serum osteocalcin concentrations were observed 3 and 6 months after kidney transplantation with a significant correlation with alkaline phosphatase levels. The increase in serum osteocalcin levels observed in our transplanted patients is not related with a parallel increase in serum creatinine levels nor with an increment in PTH levels; it seems to reflect an increase in the osteoblastic activity, which is not altered by steroid therapy.

Adolescent↗
PubMed1997

Neutrophils accentuate renal cold ischemia-reperfusion injury. Dose-dependent protective effect of a platelet-activating factor receptor antagonist.

This study was undertaken to evaluate whether the renal damage induced by cold ischemia-reperfusion was worsened by neutrophils (PMN), and if blockade of platelet-activating factor (PAF) could effectively decrease this injury. After flushing with EuroCollins, 85 kidneys from Sprague-Dawley rats underwent either no cold ischemia or a 4-h cold ischemia, and then were reperfused for 75 min at 37 degrees C and 100 mm Hg in an isolated perfusion circuit. Reperfusion was performed with a Krebs-Henseleit solution containing 4.5% albumin, with and without human PMN (7.5 x 10(5) cells/ml) and with and without addition of a PAF receptor antagonist (BN 52021). Hemodynamic and functional parameters were continuously assessed during reperfusion. At end of the study, PAF production was evaluated. Presence of PMN during reperfusion of nonischemic kidneys produced no alteration of functional parameters or PAF production. After 4-h cold ischemia, the presence of PMN during reperfusion produced a significant worsening of plasma flow rate, glomerular filtration rate and sodium reabsorption in comparison with kidneys reperfused without PMN. Also, higher production of PAF was observed in the kidneys reperfused with PMN than in the kidneys reperfused without PMN. After 4-h cold ischemia, addition of BN 52021 during reperfusion in the presence of PMN significantly increased the plasma flow rate, glomerular filtration rate and sodium reabsorption in comparison with kidneys reperfused without this PAF antagonist. This effect was dose dependent. After 4-h cold ischemia, addition of BN 52021 during reperfusion in the absence of PMN produced no significant effect on functional parameters in comparison with kidneys reperfused without this PAF antagonist. These results indicate that PMN contribute to renal cold ischemia-reperfusion injury evaluated in the isolated perfused kidney. Treatment with a PAF receptor antagonist attenuated this injury in a dose-dependent manner, which suggests that it is mediated by PAF.

Animals↗