Effect of a highly selective endothelin-converting enzyme inhibitor on cardiac remodeling in rats after myocardial infarction.

Whilst endothelin (ET) receptor antagonism has been evaluated in post-myocardial infarction (MI) remodeling, endothelin-converting enzyme (ECE) inhibition has not been determined. In the study reported here female Sprague-Dawley rats underwent coronary artery ligation, then were randomized 24 h post-MI to either no therapy (control) or 7 days therapy with the highly selective ECE inhibitor, FR901533 (Fujisawa, Osaka, Japan) 100 mg/kg/day, by continuous subcutaneous infusion. Echocardiography [fractional shortening (FS), internal dimensions and relative wall thickness (RWT)] and invasive hemodynamics were performed before sacrifice on day 8, with subsequent cardiac immunohistochemistry. Plasma concentrations of ET-1 and big ET-1 (39 AA) were determined by enzyme-linked immunosorbent assay (ELISA). ECE inhibitor-treated rats [n = 6, infarct size (IS) 37 +/- 2%) were compared to control rats with similar size MI (n = 8, IS 38 +/- 3%). Values for sham-operated rats were: RWT 0.49 +/- 0.02; left ventricular end-diastolic diameter (LVEDD) 6.2 +/- 0.5 mm; left ventricular end-systolic diameter (LVESD) systolic3.5 +/- 0.5 mm; blood pressure (SBP) 119 +/- 4 mmHg; heart rate 340 +/- 21 bpm; and left ventricular end-diastolic pressure (LVEDP) 12 +/- 2 mmHg, FS 46 +/- 4%. ECE inhibition was confirmed by increased big ET-1 to ET-1 ratio (0.23 +/- 0.06 vs 0.05 +/- 0.02, ECE inhibitor vs control, p < 0.05). ECE inhibitor increased RWT (0.43 +/- 0.03 vs 0.35 +/- 0.02, p < 0.05) contributed to by reduced left ventricular (LV) internal dimensions (EDd 7.5 +/- 0.4 vs 7.9 +/- 0.3 mm, ESd 5.2 +/- 0.5 vs 5.6 +/- 0.3 mm, ECE inhibitor vs control respectively). There were also trends in ECE inhibitor rats to increased FS (31 +/- 4 vs 29 +/- 2%), decreased SBP (99 +/- 4 vs 104 +/- 4 mmHg), heart rate (355 +/- 28 vs 385 +/- 12 bpm) and LVEDP (23 +/- 2 vs 25 +/- 1 mmHg), all p = NS, ECE inhibitor vs control. Immunoreactive cardiac collagen I peptide was unchanged by ECE inhibitor, however, alpha-smooth muscle actin, a marker of myofibroblast activation, was decreased in the infarct zone of ECE inhibitor rats (35 +/- 4 vs 46 +/- 3%, ECE inhibitor vs control, p < 0.05). This study concludes that selective ECE inhibitor with FR901533 reduces the conversion of big ET-1 to ET-1 in post-MI rats and improves some parameters of cardiac remodeling early post-MI. However, longer-term studies are needed fully to assess the therapeutic potential of ECE inhibitor post-MI and in heart failure.

Functional, histological, and inflammatory changes in chronically rejecting small bowel transplants.

Our aim was to develop a model of chronic rejection (CR) in small bowel allografts, and to study the changes occurring in these grafts. Small bowel transplantation was performed using the DA to AS rat strain combination. Short-term (5 mg/kg intramuscular, from days -2 to +9), or long-term cyclosporin treatment (5 mg/kg, 3 times a week until day 50) was given to prevent acute rejection. Controls were untreated allografts, DA isografts with and without cyclosporin, and normal DA and AS rats. They were followed for 50 and 100 days after transplantation. Recipients of a syngeneic graft lost weight during the first week after transplantation, but started to regain weight and kept growing thereafter. Histology showed normal bowel architecture with normal mesenteric lymph nodes and Peyers patches. Vigorous acute rejection occurred in the untreated allografts. Animals had persistent weight loss, and were killed between 6-13 days after transplantation. No clinical signs of graft-versus-host disease were seen. Histology showed end-stage acute rejection. In both cyclosporin-treated allografted groups the postoperative course was as in the isografted animals. However, all animals had histologic signs of CR by 50 and 100 days after transplantation. Changes were most prominent in the mesentery. Serositis with increased vascularity, inflammation with sclerosis, and patchy myointimal proliferation with endothelialitis of the mesenteric vessels were found. Changes in the bowel were patchy and included some thickening of the muscle coat, crypt hyperplasia, scattered necrotic cells in the crypts, slight blunting of villi and loss of goblet cells. Infiltrating cells in the mesentery and bowel consisted mainly of CD 4+ cells, CD 8- T-cells and monocytes/macrophages. Lactulose-mannitol urinary excretion ratio was significantly increased in short-term cyclosporin treated allografts at days 50 and 100 posttransplant. Serum albumin levels were significantly lowered in this group at both time points examined. We developed two models in which CR occurs after small bowel transplantation. Long-term cyclosporin treatment delayed the development of CR, since functional abnormalities were only seen in the animals that were treated with short-term cyclosporin.

The type I and type II 11beta-hydroxysteroid dehydrogenase enzymes.

Local tissue concentrations of glucocorticoids are modulated by the enzyme 11beta-hydroxysteroid dehydrogenase which interconverts cortisol and the inactive glucocorticoid cortisone in man, and corticosterone and 11-dehydrocorticosterone in rodents. The type I isoform (11beta-HSD1) is a bidirectional enzyme but acts predominantly as a oxidoreductase to form the active glucocorticoids cortisol or corticosterone, while the type II enzyme (11beta-HSD2) acts unidirectionally producing inactive 11-keto metabolites. There are no known clinical conditions associated with 11beta-HSD1 deficiency, but gene deletion experiments in the mouse indicate that this enzyme is important both for the maintenance of normal serum glucocorticoid levels, and in the activation of key hepatic gluconeogenic enzymes. Other important sites of action include omental fat, the ovary, brain and vasculature. Congenital defects in the 11beta-HSD2 enzyme have been shown to account for the syndrome of apparent mineralocorticoid excess (AME), a low renin severe form of hypertension resulting from the overstimulation of the non-selective mineralocorticoid receptor by cortisol in the distal tubule of the kidney. Inactivation of the 11beta-HSD2 gene in mice results in a phenotype with similar features to AME. In addition, these mice show high neonatal mortality associated with marked colonic distention, and remarkable hypertrophy and hyperplasia of the distal tubule epithelia. 11Beta-HSD2 also plays an important role in decreasing the exposure of the fetus to the high levels of maternal glucocorticoids. Recent work suggests a role for 11beta-HSD2 in non-mineralocorticoid target tissues where it would modulate glucocorticoid access to the glucocorticoid receptor, in invasive breast cancer and as a mechanism providing ligand for the putative 11-dehydrocorticosterone receptor. While previous homologies between members of the SCAD superfamily have been of the order of 20-30% phylogenetic analysis of a new branch of retinol dehydrogenases indicates identities of > 60% and overlapping substrate specificities. The availability of crystal structures of family members has allowed the mapping of conserved 11beta-HSD domains A-D to a cleft in the protein structure (cofactor binding domain), two parallel beta-sheets, and an alpha-helix (active site), respectively.

EGF and TGF-beta1 gene expression in chronically rejecting small bowel transplants.

Long-term survival of small bowel transplants is hampered by chronic rejection. Epidermal growth factor (EGF) and transforming growth factor beta (TGF-beta) have opposing, regulatory roles in normal intestinal physiology and may be involved in the pathogenesis of chronic intestinal rejection. Our aim was to investigate the expression of EGF and TGF-beta1 in chronically rejecting small bowel transplants. Orthotopic small bowel transplantation was performed in the allogeneic DA-to-AS rat combination; Cyclosporin was administered temporarily to prevent acute rejection. Controls were DA isografts and normal DA rats. PreproEGF and TGF-beta1 gene expression was evaluated by northern blot analysis of the ileum RNA and standardized against glyceraldehyde-3-phosphate-dehydrogenase expression. Allografts demonstrated functional impairment and histological features of chronic rejection, whereas isografts appeared normal. Allografts demonstrated a significant reduction of EGF mRNA when compared to DA isografts. No significant changes were detected in TGF-beta1 expression in either allogeneic or syngeneic grafts. In conclusion, this study demonstrates reduced preproEGF and preserved TGF-beta1 gene expression in chronically rejecting small bowel transplants.

Development of injury in a rat model of chronic renal allograft rejection: effect of dietary protein restriction.

Non-allogeneic factors such as increased nephron "workload" may contribute to chronic renal allograft rejection. Reducing dietary protein from 20% to 8% was tested in a model of chronic rejection: Dark Agouti kidney to Albino Surgery recipient, "tolerised" by previous donor blood transfusions. Survival, weight gain, serum creatinine concentration and creatinine clearance were similar for both groups at all times. Urinary protein was significantly (P < 0.05) lower in the low-protein (LP) group 1 month after transplantation. After 3 and 6 months, both groups demonstrated mild chronic rejection. After 6 months, tubular atrophy was significantly (P < 0.05) less in the LP group and interstitial fibrosis was marginally reduced. Glomerular hypertrophy, glomerular sclerosis, tubular dilatation, leucocyte infiltration, adhesion molecule expression and TGF-beta1 mRNA expression were similarly increased in both groups. Thus, reducing dietary protein to 8% lowered urinary protein, but did not significantly affect the development of chronic rejection in renal allografts beyond affording a degree of protection from tubulointerstitial damage.

Increased expression of basic fibroblast growth factor during chronic rejection in intestinal transplants is associated with macrophage infiltrates.

Long-term survival of intestinal transplants is hampered by chronic rejection (CR). Since transplants with CR demonstrate fibrotic changes, the cytokine basic fibroblast growth factor (bFGF) may be involved in the tissue remodelling of chronic intestinal rejection. The aim of this study was to investigate the bFGF gene and protein expression and distribution in chronically rejecting intestinal allografts. Orthotopic small bowel transplantation was performed in the allogeneic DA-to-AS rat combination. Cyclosporin was administered temporarily to prevent acute rejection. Controls were DA isografts and normal DA. bFGF gene expression was evaluated using reverse transcriptase polymerase chain reaction (RT-PCR) of the ileum RNA and was standardized against Glyceraldehyde-3-phosphate-dehydrogenase (GAP-DH) expression. bFGF protein was determined using immunohistochemistry. To identify the bFGF-positive cell type, sequential sections were stained for cell markers. Allografts showed histological features of CR, whereas isografts preserved normal architecture. bFGF gene expression was present in normal ileum and significantly upregulated in allografts. Immunohistochemical staining showed a significant increase in bFGF protein compared to isografts. Most bFGF-positive cells were localized in the submucosa and muscularis, particularly around the neural plexus. bFGF-positive cells appeared to be ED-2-positive macrophages, strongly suggesting that the site of bFGF production is the activated macrophage. This study demonstrates increased bFGF mRNA and protein in chronically rejecting intestinal allografts that appear to be produced by macrophages.

Redefining peripheral tolerance in the BALB/c to CBA mouse cardiac allograft model: vascular and cytokine analysis after transient CD4 T cell depletion.

BACKGROUND: To evaluate cardiac allografts from recipients that had achieved peripheral tolerance after transient CD4+ T cell depletion, we analyzed cellular infiltrate, cytokine expression, and vascular thickening. Long-surviving cardiac allografts from tolerant recipients were compared with acutely rejecting allografts and isografts. METHODS AND RESULTS: In CBA mice treated with anti-CD4 (GK1.5, 0.5 mg intraperitoneally on days 1-28), BALB/c cardiac allografts survived >100 days. These recipients were tested for tolerance at >70 days, by challenge with donor and third-party (C57BL/6) skin grafts. BALB/c skin grafts survived >30 days, although C57BL/6 skin was rejected in <12 days, reflecting alloantigen-specific peripheral tolerance. When vascular thickening in graft arteries was assessed and computerized measurements performed, heart allografts from tolerant recipients showed significantly increased percentage of luminal occlusion compared with isografts (47% compared with 1.2%). Semiquantitative reverse transcriptase-polymerase chain reaction was used to assess normalized intragraft mRNA transcripts for cytokines and T cell markers, with immunoperoxidase staining of frozen sections to confirmed the presence of protein. Compared with rejecting grafts, well-preserved hearts from tolerant mice had lower levels of macrophage and T cell infiltration and decreased transcription of interferon-gamma, interleukin (IL)-2, IL-10, and inducible nitric oxide synthase. IL-4 expression was similar in both groups. CONCLUSIONS: The degree of tolerance achieved allowed specific acceptance of donor skin grafts, preserved primary graft function, and reduced inflammatory activation. Tolerance did not, however, completely prevent macrophage and T cell infiltration of the graft or the development of vascular lesions typical of chronic rejection.

Collagen induced arthritis in rats. Contrasting effect of subcutaneous versus intradermal inoculation of type II collagen.

OBJECTIVE: To determine the effect of subcutaneous (s.c.) as compared to intradermal (i.d.) inoculation of collagen type II (CII) in induction of collagen induced arthritis (CIA). METHODS: Dark Agouti (DA) and Lewis rats were injected with CII either i.d. or s.c.. A group of s.c. inoculated DA rats was re-injected with CII intradermally 45 days after first injection (s.c./i.d.). Arthritis was assessed by macroscopic scoring, histology, and immunohistochemistry. Levels of anti-CII antibody subtypes were measured by ELISA. RESULTS: Intradermal but not s.c. inoculation of CII resulted in histologically confirmed erosive arthritis in both Lewis and DA strains. Subcutaneous/intradermal inoculated DA rats developed mild CIA with lower arthritic scores and delayed onset. Lewis rats injected s.c. had lower levels of total Ig, IgG, IgG2a, and IgG2b and similar titers of IgG1 compared to i.d. inoculated rats. In contrast, only IgG2b levels were lower in s.c./i.d. compared to i.d. rats. CONCLUSION: Our data suggest that s.c. administration of CII tolerises animals against autoimmune CIA.

Long-term survival of segmental pancreas isografts in NOD/Lt mice treated with anti-CD4 and anti-CD8 monoclonal antibodies.

Spontaneously diabetic nonobese diabetic (NOD/Lt) mice were treated with anti-T-cell monoclonal antibodies (mAbs) at the time of grafting with vascularized segmental pancreas isografts. Recipients were either untreated or given anti-CD4 and/or anti-CD8 mAbs (0.5 mg/20-g mouse on each of 4 consecutive days), which reduced target cell levels to <5% of normal. Graft function was monitored by measuring blood glucose (BG) levels. Transplants were removed for histological examination when BG returned to >20 mmol/l for two consecutive readings. Isografts from 3- to 4-week-old prediabetic mice placed in untreated diabetic NOD mice ceased functioning in 9-13 days with a mean survival time (MST) +/- SD of 10 +/- 2. Treatment with anti-CD4 prolonged survival significantly (MST = 61 +/- 35 days, P < 0.05 compared with untreated control mice). Anti-CD8 treatment was less effective, but it still significantly improved graft survival (MST = 24 +/- 9 days, P < 0.05 compared with untreated control mice). Anti-CD8 plus anti-CD4 treatment was highly effective in inhibiting autoimmune destruction of the grafts (MST = 97 +/- 8 days). This clearly demonstrates that transient inactivation of most T-cells with anti-CD4 plus anti-CD8 mAbs effectively controls autoimmune disease in the isograft, despite recovery of CD4 and CD8 T-cells to normal levels. Although insulitis developed in the long-term grafts, insulitis scores did not increase between 33 and 100 days, and none of the mice progressed to IDDM in 100 days. Histology showed a predominantly peri-islet T-cell and macrophage infiltrate with ductal expression of the cytokines interleukin (IL)-4, IL-2, and interferon-gamma. There was little infiltrate or expression of cytokines within the islets. Thus, mAb treatment at the time of grafting allowed isograft survival and prevented progression from insulitis to beta-cell destruction.

Cardiac allografts from IL-4 knockout recipients: assessment of transplant arteriosclerosis and peripheral tolerance.

To study the role of IL-4 in tolerance induction and transplant arteriosclerosis, BALB/c hearts were transplanted into C57BL/6J wild-type or IL-4 knockout (IL-4(-/-)) recipients. A 30-day course of anti-CD4/8 mAb was used to induce long term graft survival. Primary graft survival was 50% (5 of 10) in IL-4(-/-) recipients comparable to 63% (5 of 8) in wild-type recipients. Mice with allografts surviving >80 days were tested for tolerance by challenge with a second donor or third party (CBA) heart. Secondary donor-strain heart grafts survived >30 days, but showed histologic evidence of ongoing alloimmune response. Third party hearts rejected rapidly. Although immunostaining and 32P RT-PCR assays showed no differences in the mononuclear cell infiltration and T cell activation between IL-4(-/-) and wild-type tolerant recipients, some monokines (IL-12, TNF-alpha, and allograft inflammatory factor-1) were up-regulated in grafts from IL-4(-/-) recipients. Computer-assisted analysis of elastin-stained vessels revealed that the severity of vascular thickening (percentage of luminal occlusion, mean +/- SD, n = 329) was similar in grafts from IL-4(-/-) (63.7 +/- 16.9%) and wild-type (69.5 +/- 17.6%) recipients. Thus, IL-4 deficiency did not alter primary or secondary graft survival, infiltration, or vascular thickening. The selective alterations in monokine expression suggests that alternative pathways are activated and may compensate in IL-4(-/-) mice.

Interleukin (IL) 4, the cytokine that isn't there: reactivity of IL-4 antibodies with cells in IL-4 -/- mice.

We analyzed cytokine expression in recipient spleens and cardiac allografts placed in mice that were unable to synthesize interleukin (IL)-4 due to disruption of the IL-4 gene (IL-4 -/-) and in wild-type (IL-4 +/+) mice. Polyclonal BL-4P and monoclonal 11B11, 1D11, and 24G2 anti-IL-4 antibodies were used to detect cell-surface and cytoplasmic antigens in sections of frozen tissue. All of the antibodies were found to react with non-IL-4 determinants associated with graft-infiltrating cells, and BL-4P, 1D11, and 24G2 bound to cells and connective tissue in the spleens of IL-4 -/- mice. The IL-4-producing cell line, X63Ag8-653 (X63), was used as a positive control for IL-4 staining and to test the ability of recombinant IL-4 to block the binding of antibodies to IL-4.

Altered expression of fibrogenic growth factors in IgA nephropathy and focal and segmental glomerulosclerosis.

The profile of fibrogenic growth factor expression was assessed in biopsies from 27 patients with IgA nephropathy (IgAN), 14 focal and segmental glomerulsclerosis (FSGS) patients and 8 controls, by immunohistochemistry. Increased platelet-derived growth factor (PDGF)-A and PDGF-B expression was detected in glomeruli and in vascular structures and collapsed tubules in the interstitium. Computer assisted image analysis demonstrated increased glomerular PDGF-A in IgAN (P < 0.05), but not FSGS patients, compared to controls, suggesting an association with mesangial proliferation. PDGF receptors were prominent in areas of mesangial expansion and intertubular fibrosis. Significant increases in interstitial PDGF Receptor beta (PDGFR-beta) were detected for both IgAN (P < 0.01) and FSGS (P < 0.05) patients. Interstitial PDGFR-beta expression was significantly correlated to monocyte/macrophage infiltrate (P < 0.0001). Increased basic fibroblast growth factor (bFGF) expression was observed segmentally in glomeruli, and in areas of tubulointerstitial damage. Higher proportions of patients with FSGS than IgAN had elevated interstitial bFGF (P < 0.005) and PDGF, reflecting the more severe degree of vascular and tubulointerstitial injury in FSGS patients. This study demonstrates distinct patterns of fibrinogenic growth factors in IgAN and FSGS, strongly associated with the severity and type of injury.

Localization of 11 beta-hydroxysteroid dehydrogenase type II in human epithelial tissues.

The enzyme 11 beta-hydroxysteroid dehydrogenase type II (11 beta HSD2) confers specificity on the renal mineralocorticoid receptor by inactivating glucocorticoids. Mutations in this gene give rise to the syndrome of apparent mineralocorticoid excess, a congenital condition characterized by sodium retention, severe hypertension, and often by growth retardation. It is not known whether 11 beta HSD2 or another enzyme confers specificity in nonrenal sodium transporting epithelia, such as those in the sweat gland, salivary gland, and gastrointestinal tract. We previously have used the HUH23 antibody to localize 11 beta HSD2 in the human kidney, vascular smooth muscle cells, and placenta. In the present study, we have examined a range of human epithelia for the presence of 11 beta HSD2. In the skin, staining was seen in eccrine sweat glands and arterioles, whereas weak HUH23 immunostaining was observed in the epidermis. Staining was absent from sebaceous glands and hair follicles. In the parotid gland, the 11 beta HSD2 enzyme was present in striated and excretory ducts, whereas in the submandibular gland, it was found in striated and interlobular ducts. Acini, adipocytes, and associated tumor tissue did not stain with the HUH23 antibody. In the gastrointestinal tract, HUH23 stained ileal enterocytes, colonic absorptive cells, and epithelial goblet cells, whereas the rectum contained areas of staining and nonstaining absorptive cells. Gastrointestinal structures, such as the lamina propria, Peyer's patch, and goblet cells within the crypts of Lieberkuhn did not stain with the antibody. This study demonstrates the presence of 11 beta HSD2 in nonrenal sodium-transporting epithelia and describes a range of tissues affected in the syndrome of apparent mineralocorticoid excess.

Vascular localization of the 11 beta-hydroxysteroid dehydrogenase type II enzyme.

1. The enzyme 11 beta-hydroxysteroid dehydrogenase type II (11 beta HSD2) confers specificity on the non-specific mineralocorticoid receptor by converting cortisol to cortisone. 2. We have examined the localization of this enzyme in the human skin, myocardium and saphenous vein by immunohistochemical techniques. 3. High amounts of 11 beta HSD2 immunoreactivity were found in smooth muscle cells in the arterioles of the skin, heart and saphenous vein. Lower amounts of staining were also found in longitudinal and concentric smooth muscle cells lining the lumen of the saphenous vein.

Immunohistochemical localization of the 11 beta-hydroxysteroid dehydrogenase type II enzyme in human kidney and placenta.

It has been proposed that the inactivation of glucocorticoids by the enzyme 11 beta-hydroxysteroid dehydrogenase (11 beta HSD) is an obligatory step in the kidney, permitting binding of aldosterone to the mineralocorticoid receptor, and in the placenta, protecting the fetus from high circulating levels of maternal glucocorticoids. Both low and high affinity isoforms of 11 beta HSD are known to exist, with evidence accumulating that the former species (11 beta HSD1) does not fulfill criteria that would allow it to perform these physiological functions. We have recently cloned a high affinity isoform of the enzyme (11 beta HSD2) from a human kidney library and have shown this species to possess all of the characteristics predicted from whole cell studies. In the present study we have raised a polyclonal antibody (HUH23) to a synthetic peptide deduced from the carboxy-terminus of the protein. The immunopurified antibody recognized a single band at 41,000 daltons on Western blots of mammalian cells transfected with an expression plasmid containing 11 beta HSD2, slightly smaller than the predicted 44,140 daltons protein. A single band of identical size was also seen in blots of human kidney and placenta, suggesting post-translational processing of the enzyme. Immunohistochemical studies on frozen sections of human kidney showed strong 11 beta HSD2 immunoreactivity in the cortical distal convoluted tubules and collecting ducts. Strong staining was also observed in medullary tubules, which had the appearance of collecting ducts and the thick ascending limb of Henle's loop. Staining of medium intensity was observed in vascular smooth muscle cells. Epithelial cells of glomeruli showed weak but detectable reactivity with HUH23. In the placenta, HUH23 antibody immunoreactivity was restricted to syncytial trophoblast cells in which strong staining was observed. These results suggest that the 11 beta HSD2 enzyme colocalizes with the mineralocorticoid receptor in the distal nephron where it allows aldosterone to occupy its physiological receptor. Furthermore, 11 beta HSD2 is also ideally situated in the placenta to protect the fetus from high circulating levels of maternal glucocorticoids.

The effect of ureteric stenting on the function and morphology of long-term rat renal allografts.

In the development of a reliable model for chronic rejection in rat renal allografts, the effect of modifying the ureteric anastomosis was tested. Rats, tolerized by pretreatment with two donor blood transfusions under Cyclosporin A, received renal allografts with either sewn or stented ureter. Control groups received isografts or underwent uninephrectomy with insertion of ureteric stents. For the first 6 days after transplantation, serum creatinine and urea values were lower in allograft recipients with stented ureters than in the group with sewn ureters. The method of ureteric anastomosis did not affect the long-term incidence of abnormal function. Allograft morphology was extremely variable from minor to extensive tubular atrophy, interstitial fibrosis, glomerular hypertrophy, focal and segmental glomerulosclerosis as well as vascular changes. Glomerulosclerosis was absent in controls and increased with time in the allografts. Two hundred days after transplantation all allograft recipients with sewn ureters exhibited some glomerulosclerosis, in half of these kidneys more than 25% of glomeruli were affected. Only 33% recipients of allografts with stented ureters exhibited some glomerulosclerosis and less than 20% of glomeruli were affected. The stented ureteric anastomosis provides a reliable method, a reduction of the technical failure rate, a reduction of the incidence of hydronephrosis, allows more accurate assessment of early renal function and may be of importance in reducing the occurrence and prevalence of glomerulosclerosis in the long-term allografts.