BACKGROUND: Chronic renal allograft nephropathy is characterized by an abnormal accumulation of extracellular matrix proteins in the glomeruli and tubulo-interstitium. The aim of this study was to determine the relationship between intragraft expression of the genes controlling the accumulation of extracellular matrix and the development of chronic renal allograft nephropathy in human renal transplants. METHODS: Forty renal allografts with stable renal function were biopsied 6 months after transplantation. Single glomeruli were plucked from the surface of these protocol biopsies and total messenger RNA (mRNA) was extracted. Reverse transcriptase-polymerase chain reaction was used to study the intragraft expression of several fibrosis-associated genes (collagen III, collagen IValpha2, matrix metalloproteinase (MMP) 2, tissue inhibitors of metalloproteinases (TIMPs) 1 and 2, tenascin and transforming growth factor (TGF) beta1). The level of tubulo-interstitial fibrosis was measured by quantitative immunostaining of collagen III. RESULTS: There were positive correlations between the level of tubulo-interstitial collagen III immunostaining and intragraft expression of the genes for TIMP-1 (rs= 0.70, P < 0.02) and TIMP-2 (rs = 0.59, P < 0.02). Interstitial fibrosis was also strongly correlated with the levels of TGF-beta mRNA (rs = 0.67, P < 0.002). Finally, TIMP-1 expression increased with TGF-beta expression (rs = 0.77, P < 0.002). CONCLUSION: Failure of extracellular matrix degradation may be an important molecular mechanism in the pathogenesis of chronic renal allograft damage.

Biopsy, Needle↗

PubMed2002

Microemulsion cyclosporin inhibits vascular remodelling and attenuates associated changes in profibrotic gene expression in an experimental model of allograft vasculopathy.

BACKGROUND: Chronic allograft dysfunction (CAD), the leading cause of solid organ transplant failure, is characterized by histological evidence of extracellular matrix (ECM) accumulation (fibrosis). The aim of this study was to characterize the changes in fibrosis-associated gene expression in an experimental model of CAD and to measure the effect of the immunosuppressant cyclosporin on these changes. METHODS: Lewis recipients of F344 rat thoracic to abdominal transplants were administered cyclosporin or no treatment. Vascular remodelling and ECM accumulation (picrosirius red) were measured using computerized histomorphometry. Fibrosis-associated gene expression was studied by semiquantitative reverse transcription-polymerase chain reaction. RESULTS: Cyclosporin inhibited medial ECM accumulation and vascular remodelling in allografts. This was associated with an attenuation of the graft inflammatory infiltrate and a reduction in intragraft matrix metalloproteinase (MMP) 2 and MMP-9 messenger RNA (mRNA) levels. There was a significant negative correlation between neoadventitial ECM density and MMP-9 expression, as well as with vessel circumference. Neoadventitial ECM density was significantly higher in the cyclosporin-treated group than in animals with untreated allografts, as were mRNA levels of collagen 3 and tissue inhibitor of metalloproteinase 1. CONCLUSION: The alloimmune injury itself may contribute directly to vascular remodelling and fibrosis in allograft vasculopathy. Cyclosporin attenuated this component of the pathophysiology of CAD effectively.

Animals↗

PubMed2002

Effects of the combination of rapamycin with tacrolimus or cyclosporin on experimental intimal hyperplasia.

BACKGROUND: Allograft vasculopathy remains the leading cause of late allograft failure following transplantation and can be inhibited by the antiproliferative drug rapamycin. This study assessed the efficacy of combining rapamycin therapy with calcineurin inhibition. METHODS: Male Sprague-Dawley rats received rapamycin 0.05 mg/kg daily and either tacrolimus 0.1 mg/kg or cyclosporin 5 mg/kg daily, and findings were compared with those in an untreated control group. Animals underwent left common carotid artery balloon angioplasty; the artery was explanted after 2 weeks. Morphometric analysis was performed on transverse sections and the intima : media ratio was calculated. Profibrotic gene expression was measured with competitive reverse transcriptase-polymerase chain reaction at 14 and 28 days. Proliferation was determined with proliferating cell nuclear antigen at 14 and 28 days. Extracellular matrix deposition was quantified with Sirius red. RESULTS: The combination of rapamycin and tacrolimus was associated with the greatest reduction in intimal thickening. Furthermore, treatment with rapamycin and tacrolimus significantly attenuated extracellular matrix deposition compared with rapamycin and cyclosporin (P < 0.02). CONCLUSION: The effects of rapamycin in combination with tacrolimus were better than those observed with rapamycin and cyclosporin.

Animals↗

PubMed2002

Pirfenidone inhibits early myointimal proliferation but has no effect on late lesion size in rats.

AIMS: intimal hyperplasia is mediated by smooth muscle cell proliferation, migration and deposition of extracellular matrix. The anti-fibrotic agent pirfenidone has been shown to inhibit pro-fibrotic growth factors in non-vascular inflammatory models. This study investigated the effect of the novel anti-fibrotic agent pirfenidone on the development of neointima. METHODS: male Sprague-Dawley rats received either standard diet or diet supplemented with pirfenidone (250, 500, 1000 mg/kg/day). Animals underwent left common carotid balloon angioplasty and were explanted at 4, 8, 14 and 28 days and analysed for intimal thickening, pro-fibrotic gene expression, extracellular matrix deposition and metalloproteinase activity. RESULTS: neointimal thickness was significantly reduced in a dose-dependent manner at 14 days; pirfenidone 250 mg/kg (p<0.005), pirfenidone 500 mg/kg (p<0.001), pirfenidone 1 g/kg ( p<0.001). There were no significant differences in intimal thickening at 28 days. Expression of MMP-2, MMP-9, TIMP-1, collagen III and TGF-beta were all significantly inhibited at 14 days. Both collagen III expression and ECM deposition were reduced at 28 days ( p<0.05 and <0.002 respectively). CONCLUSION: pirfenidone reduces expression of MMPs governing smooth muscle cell proliferation and migration (MMP-2 and 9), and genes favouring ECM accumulation (TIMP-1 and collagen III). This study shows that inhibition of MMP activity is not sufficient to inhibit late lesion size.

Angioplasty, Balloon↗

PubMed2002

Autogeneous elbow fistulas: the effect of diabetes mellitus on maturation, patency, and complication rates.

OBJECTIVES: diabetes mellitus is an increasingly common cause of end stage renal failure (ESRF) and the establishment of adequate permanent vascular access for dialysis is a major cause of morbidity and mortality in these patients. The aim of this study was to compare the availability of suitable vein, maturation rates, patency and complication rates of autogeneous elbow fistulas in diabetics and non-diabetics at a single centre where an autogeneous vein only policy is employed. DESIGN: retrospective series. PATIENTS AND METHODS: two hundred and ninety-three elbow fistulas were attempted in 232 patients over a seven year period, [median age 60 years (range 14-94 years)], of which 210 were in non-diabetic and 83 were in diabetic patients. The diabetic group had a significantly higher proportion of male patients (p < 0.05), peripheral vascular disease and established ESRF. RESULTS: there was a trend towards a higher technical success rate in the non-diabetic group (98% versus 93% p = 0.057). There was no significant difference between the primary failure rate, fistula maturation rate, revision rate or incidence of complications between the two groups. Diabetes had no effect on cumulative secondary fistula patency even when stratified for Type 1/Type 2 diabetes, female sex, old age or primary versus subsequent procedures. CONCLUSION: diabetes mellitus has no significant detrimental effect on outcome following formation of autogeneous elbow fistulas for haemodialysis.

Adolescent↗

PubMed2002

Living kidney donation: a comparison of laparoscopic and conventional open operations.

Laparoscopic donor nephrectomy has the potential to lessen the burden placed on live kidney donors. This study describes the first British comparison of donor morbidity and recovery following conventional open donor nephrectomy (ODN) and laparoscopic donor nephrectomy (LDN). An initial series of LDN (n=20) was compared to a historical control group of ODN (n=34). Laparoscopic operations were performed via a transperitoneal approach, the kidney being removed through a 6--12 cm Pfannensteil incision. Open operations were performed using a retroperitoneal flank approach with resection of the 12th rib. Postoperatively, donors were managed with a patient controlled analgesia system. LDN was associated with shorter mean (SD) inpatient stay (6 (2) v 4 (1) days; p=0.0001) and lower parenteral narcotic requirements (morphine 179 (108) v 67 (54) mg; p=0.0001). Laparoscopic donors started driving their cars sooner (2 (1.5) v 6 (4) weeks; p=0.0001) and returned to work more quickly (5 (3) v 12 (6) weeks; p=0.0001) than open nephrectomy donors. There were no differences in recipient serum creatinine levels at three months post-transplant but two recipients of transplant kidneys retrieved laparoscopically (10%) developed ureteric obstruction, whereas this complication did not occur after ODN (p=0.13). LDN is associated with less postoperative pain and a substantial improvement in donor recovery times. It is not yet clear whether or not the outcome of the recipient kidney transplants are the same after ODN and LDN and much more experience is required before the place of this new technique can be defined.

Adult↗

PubMed2002

Elbow fistulas using autogeneous vein: patency rates and results of revision.

BACKGROUND: The provision and maintenance of vascular access remains a major cost to end stage renal failure programmes. There are few reports regarding the surgical revision of the failing native elbow arteriovenous fistula (AVF). PATIENTS AND METHODS: A retrospective case note review was performed on all patients identified from the hospital vascular access database as having undergone construction of an autogeneous vein elbow AVF. Over a seven year period 282 autogeneous vein AVFs were fashioned in 232 patients using the brachial artery as the in-flow conduit. Of these 208 were brachiocephalic fistulas, or a variant thereof, and 74 were fashioned using the transposed autologous basilic vein (136 male: 96 female; median age 60 years, range 14-94 years). RESULTS: Of 282 elbow fistulas 197 were successfully used for dialysis (70%). Cumulative primary patency of elbow fistulas using autogeneous vein in this series was 68%, 54%, and 44% at one, two, and three years respectively. A further 34 revision procedures were performed on 28 fistulas to maintain fistula function, and cumulative secondary patency after surgical revision was 75%, 60%, and 46% at one, two, and three years. Overall 21 out of 34 procedures (62%) successfully restored fistula function and cumulative primary patency of the revised fistulas was 56% at one year. Eighteen AVFs (brachiocephalic, n=12; autologous basilar vein, n=6) required revision for access dysfunction secondary to a short stenoses within 4 cm of the arteriovenous anastomoses. Of these 18 AVFs eight were revised by excision of the stenosed segment and either primary anastomoses of the two cut ends of arterialised vein or reanastomoses of the proximal venous limb proximally on the brachial artery. In another nine fistulas the excised segment was replaced with a short interposition graft (polytetrafluoroethylene, n=7; native basilic vein, n=1; bovine carotid artery, n=1). One fistula with postanastomotic stenoses and a more proximal needle site stenoses was revised using two vein patches. Overall 100% were patent at 24 hours, 13 provided successful dialysis (72%), and cumulative primary patency was 67% and 50% at six months and one year respectively. CONCLUSIONS: Successful surgical revision of failing native elbow fistulas can restore patency and improve cumulative secondary patency with potential benefits in terms of patient morbidity and mortality. These results compare favourably to published patency rates after fistula salvage using interventional radiological techniques.

Adolescent↗

PubMed2001

Interaction of eicosanoids and nitric oxide in renal reperfusion injury.

BACKGROUND: Both the eicosanoids and nitric oxide are known to play an important role in the pathogenesis of postischemic injury. Recent evidence has suggested that the generation of each may affect the other via a feedback loop. This was investigated in an experimental model of renal warm ischemia reperfusion injury. METHODS: Rats underwent bilateral renal warm ischemia (15-60 min) then reperfusion (20 or 80 min) followed by a unilateral nephrectomy to measure renal nitric oxide (as nitroxides) and eicosanoids. Renal function was measured on days 2 and 7 prior to terminal nephrectomy for tissue analysis. RESULTS: Vasodilator eicosanoids (6-KPGF1alpha and PGE2) fell on reperfusion in line with the duration of warm ischemia with a concomitant rise in the vasoconstrictor TxA2. The ratio of vasodilator to vasoconstrictor eicosanoids fell from 8.22 (2.3) in the control to 0.82 (0.1) in the 60-min warm ischemia group (P<0.01). Renal levels of nitroxides rose on reperfusion demonstrating an inverse correlation with the eicosanoid ratio (r2=0.86). Renal function was impaired at both day 2 and day 7 and showed a positive correlation with the eicosanoid ratio (r2=0.67 and 0.62, respectively). CONCLUSIONS: Renal warm ischemic injury is associated with a progressive fall in the ratio of vasodilator-to-vasoconstrictor eicosanoids from early in reperfusion through to day seven although nitric oxide was elevated throughout the same period. There was no evidence of coinduction of nitric oxide synthase and cyclooxygenase in this model.

Animals↗

PubMed2001

A case-control comparison of the results of renal transplantation from heart-beating and non-heart-beating donors.

INTRODUCTION: The decline in heart-beating brainstem dead organ donors has necessitated the search for other organ sources. In the field of renal transplantation one alternative source currently available, but little used, is that of kidneys from non-heart-beating donors (NHBD). Reticence to use NHBD kidneys is in part due to concerns over the effect that warm ischemic may have subsequent graft function. Presented here are the results of the NHBD renal transplants at the Leicester transplant unit, and compared with matched heart-beating donor transplants as a case control analysis. METHODS: In order to analyze any differences in graft performance between the two organ sources, the confounding effect of other variables known to influence the outcome of renal transplantation was minimized by matching NHBD and HBD transplants for the following criteria: donor age and sex, first or re-transplant, anastomosis and cold times, tissue match and PRA sensitisation. Transplant performance was assessed primarily by graft survival, the statistical evaluation of which was by log rank analysis of Kaplan-Meier curves. RESULTS: 72 NHBD and 192 HBD transplants were performed over an eight year period. Of the 192 HBD transplants, 105 matched one or more of the NHBD by the criteria outlined above, and thus constituted the control group for comparison. There was no significant difference in overall graft survival between the two groups. The 5 year survival for the NHBD was 73% compared with 65% for HBD kidneys. When death with a functioning graft is treated as censored data, then these figures become 75% and 81% respectively, again without statistical significance. CONCLUSION: NHBD kidneys are a valuable additional source of organs for transplantation, with long-term survival, comparable to transplants from HBD.

Acute Disease↗

PubMed2001

Chronic allograft nephropathy: a prospective randomised trial of cyclosporin reduction with or without mycophenolate mofetil.

Explore the source record for details and available documents.

Azathioprine↗

PubMed2001

Molecular mechanisms of renal allograft fibrosis.

BACKGROUND: Chronic graft nephropathy (CGN) remains the leading cause of renal allograft loss after the first year following transplantation. Histologically it is characterized by glomerulosclerosis, intimal hyperplasia and interstitial fibrosis. The pathogenesis is unclear, but is likely to involve both immunological and non-immunological factors. Despite improvements in short-term graft survival rates, new immunosuppressive regimens have made no impact on CGN. METHODS: A review of the current literature on renal transplantation, novel immunosuppression regimens and advances in the molecular pathogenesis of renal allograft fibrosis was performed. RESULTS AND CONCLUSION: Recent advances in understanding of the underlying molecular mechanisms involved suggest autocrine secretion of cytokines and growth factors, especially transforming growth factor beta, are associated with a change in fibroblast phenotype leading to the deposition of extracellular matrix. Repeated insults trigger upregulation of the tissue inhibitors of matrix metalloproteinases, favouring accumulation of extracellular matrix. To date, no drug has proved effective in inhibiting or reducing allograft fibrosis. The deleterious consequences of chronic immunosuppression on the development of such fibrosis are now recognized; newer immunosuppressive drugs, including rapamycin and mycophenolate mofetil, reduce profibrotic gene expression in both experimental and clinical settings, and offer potential strategies for prolonging allograft survival.

Angiotensin II↗

PubMed2001

Influence of aspirin on early allograft thrombosis and chronic allograft nephropathy following renal transplantation.

BACKGROUND: Primary thrombosis and chronic allograft nephropathy are important causes of early and late graft loss, respectively, following renal transplantation. This study examined the potential for aspirin therapy to reduce these complications. METHODS: A consecutive series of 105 cadaveric renal transplants treated with aspirin 150 mg daily for the first 3 months after transplantation was compared with an untreated historical control group (n = 121). Protocol needle-core biopsies were performed on all transplants in both groups at 1 week and 12 months after transplantation. Needle-core allograft biopsies were performed at 3, 6 and 12 months after transplantation, and serum creatinine was measured at each outpatient attendance for the duration of follow-up. RESULTS: There was a significantly lower rate of primary allograft thrombosis in patients treated with aspirin (none of 105) compared with that in the control group (six (5 per cent) of 121; P = 0.03). There were no differences in renal function or 2-year allograft survival between the two groups. Aspirin-treated patients had a lower incidence of chronic allograft nephropathy at 1 year than controls although this did not reach statistical significance (16 versus 26 per cent; P = 0.075). There were no major bleeding complications in either group in association with peptic ulcer disease or following renal transplant biopsy. CONCLUSION: Aspirin reduced the rate of early graft thrombosis of renal transplants in this series but did not improve renal function or graft survival. A trend towards a lower rate of chronic allograft nephropathy was noted with aspirin treatment. These findings require confirmation in a prospective randomized trial.

Aspirin↗