Focal segmental glomerulosclerosis in renal transplants

The aetiology and pathogenesis of chronic allograft nephropathy

Renal transplantation is the ultimate form of renal replacement therapy, and is the treatment of choice for many patients with end-stage renal failure. The advent of calcineurin inhibitor based immunosuppression resulted in the 1-year renal allograft failure rate dropping from around 50% twenty years ago to less than 10% in more recent times. Despite a massive improvement in renal allograft survival in the first year following transplantation 10-year graft survival can be as low as 50%. Chronic allograft nephropathy (CAN) is recognised as the main cause of renal allograft failure following the first year after transplantation. The diagnosis of CAN can only be made histologically. Typically biopsy specimens in grafts with CAN demonstrate an overall fibrotic appearance effecting the vascular endothelium, renal tubules, interstitium, and glomerulus. The risk factors for CAN are divided into alloimmune and alloimmune independent. Alloimmune dependent factors include acute cellular rejection, severity of rejection, subclinical rejection and HLA mismatch. Alloimmune independent factors such as delayed graft function, donor age, Cytomegalovirus infection, donor/recipient co-morbidity and of course calcineurin inhibitor toxicity are important in the development of CAN. The pathogenesis of CAN is complex, multifactorial, and unfortunately incompletely understood. There are a number of pivotal steps in the initiation and propagation of the fibrosis seen in biopsy specimens from kidneys with CAN. Endothelial activation in response to one or more of the aforementioned risk factors stimulates leukocyte activation and recruitment. Recruited leukocytes subsequently infiltrate through the endothelium and induce key effector cells to secrete excessive and abnormal extracellular matrix (ECM). Enhanced deposition of ECM is a histological hallmark of CAN. This paper aims to present a concise yet accurate and up-to-date review of the literature concerning the aetiological factors and pathological processes which are present in the generation of CAN.

Treatment of proteinuria with low-molecular-weight heparin after renal transplantation

The development of nephrotic-range proteinuria after renal transplantation is an unfavourable prognostic factor for graft survival. In contrast to that in other nephropathies, the role of renin-angiotensin blockade in kidney transplantation is less well defined, and its anti-proteinuric effect is markedly reduced in the presence of segmental glomerulosclerosis. Here, we describe two patients who developed severe proteinuria after renal transplantation, despite effective blood pressure control with an ACE inhibitor. Histological changes were consistent with IgA-nephropathy and focal segmental glomerulosclerosis. Both patients were treated with low-molecular-weight heparin in addition to pre-existing ACE inhibition. This regimen led to a significant and long-lasting reduction of proteinuria. Our data suggest that low-molecular-weight heparin possesses strong renoprotective properties, thus confirming previous data from experimental nephropathies. This approach might represent a promising new strategy for treatment of proteinuria after kidney transplantation.

Tissue transglutaminase: a mediator and predictor of chronic allograft nephropathy?

BACKGROUND

The precise mechanisms underlying the development of chronic allograft nephropathy (CAN) and the associated renal fibrosis remain uncertain. The protein-crosslinking enzyme, tissue transglutaminase (tTg), has recently been implicated in renal fibrosis. METHODS.: We investigated the involvement of tTg and its crosslink product, epsilon-(gamma-glutamyl) lysine, in 23 human kidney allografts during the early posttransplantation period and related these to changes of CAN that developed in 8 of them. Sequential biopsies were investigated using immunohistochemical, immunofluorescence, and in situ enzyme activity techniques.

RESULTS

From implantation, tTg (+266%) and epsilon-(gamma-glutamyl) lysine crosslink (+256.3%) staining increased significantly (P <0.001) in a first renal biopsy performed within 3 months from transplantation. This was paralleled by elevated tTg in situ activity. The eight patients who developed CAN had further increases in immunostainable tTg (+197.2%, P <0.001) and epsilon-(gamma-glutamyl) lysine bonds (+465%, P <0.01) that correlated with interstitial fibrosis (r=0.843, P =0.009 and r=0.622, P =0.05, respectively). The staining for both was predominantly located within the mesangium and the renal interstitium. Both implantation and first biopsies showed tTg and epsilon-(gamma-glutamyl) lysine crosslinking levels in patients who developed CAN to be twice the levels of those with stable renal function. Cox regression analysis suggested the intensity of the early tTg staining was a better predictor of inferior allograft survival that other histologic markers (hazard ratio=4.48, P =0.04).

CONCLUSIONS

tTg and epsilon-(gamma-glutamyl) lysine crosslink correlated with the initiation and progression of scarring on sequential biopsies from renal-allograft recipients who experienced CAN. Elevated tTg may offer an early predictor of the development of CAN, whereas tTg manipulation may be an attractive therapeutic target.

Post-transplant nephrotic syndrome: A comprehensive clinicopathologic study

BACKGROUND

Post-transplant (Tx) nephrotic syndrome (NS) is not well defined.

METHODS

Seventy-four renal transplant recipients with NS were studied.

RESULTS

Biopsies showed chronic allograft nephropathy (CAN) in 31 patients; recurrent glomerular disease (GN) in 15, de novo GN in 18, and undetermined GN in 9. NS developed 0.25 to 384 months post-Tx and was treated with angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) in 18 patients; calcium channel blockers in 25; or both drugs in 31. NS remitted in 24% of cases 2 to 28 months after onset, and this persisted in all except 3 patients. The remission rate was lowest (9%) for CAN and highest (47%) for de novo GN. Compared with persistent NS, those with remission showed higher prevalence of de novo GN (53% vs. 17%), lower prevalence of CAN (18% vs. 50%), earlier onset of NS (39 vs. 59 months), lower serum SCr at onset (2.3 vs. 2.9 mg/dL), and higher incidence of treatment with ACE or ARB. The 5-year graft loss rates for CAN, recurrent and de novo GN were 57%, 36%, and 23%, respectively. Compared with the functioning grafts, the failed grafts showed higher prevalence of CAN (60% vs. 16%), lower prevalence of de novo GN (12% vs. 46%), earlier onset of NS (47 vs 65 months post-Tx), higher serum SCr at onset (3.3 vs. 2.0 mg/dL), lower prevalence of remission of NS (5% vs. 48%), and higher proteinuria at follow-up (5.1 vs. 2.5 g/day). Graft survival improved with NS remission (88% vs. 18%).

CONCLUSION

Post-Tx NS displays distinctive clinicopathologic features with pathogenetic and therapeutic implications.

New aspects of posttransplant nephrotic syndrome: clinicopathologic correlations with outcomes

Although posttransplant nephrotic syndrome is frequent, its structural basis and prognosis have not been clearly defined. The biopsy findings of 54 patients with this disorder posttransplant, among 375 total renal transplant recipients engrafted during a 10-year period, were correlated with clinical follow-up data. The mean patient age was 41.7 +/- 12.3 years, female/male ratio 22/32, and cadaveric/living-related donor ratio 37/17. The nephrotic syndrome developed 3 to 91 months posttransplant. At the onset the mean values of serum creatinine was 2.9 +/- 1.8 mg/dL and proteinuria 4.5 +/- 0.8 g/d. The index biopsy findings showed chronic allograft nephropathy (CAN) in 33; de novo glomerulonephritis (GN) in 6, recurrent GN in 9, and undetermined GN in 6 who had an unknown primary renal disease. Among 21 follow-up biopsies during a mean of 44.3 +/- 28 months the CAN progressed but the GN remained the same. The treatment included augmented steroids alone (n = 1) or in combination with cyclophosphamide (n = 2) and with plasmapheresis (n = 1); angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) along (n = 5); calcium channel blockers (CCB) alone (n = 24); or the two types of drugs together (n = 22). Complete or partial remission was achieved in 8 and 5, respectively, but nephrotic syndrome recurred in 3 of these patients at 45.1 +/- 18 months later. Sustained remission was more likely in cases of GN (minimal change disease and IgA nephropathy) and ACEI-ARB treatment (P <.01). Graft failure, which occurred in 35 patients, correlated strongly with serum creatinine at onset, being significantly greater in patients with CAN (P <.005). Both remission of the nephrotic syndrome and graft survival were greater among patients with GN as compared to those with CAN.

Idiopathic focal segmental glomerulosclerosis

Idiopathic focal segmental glomerulosclerosis (FSGS) is a primary glomerular disease that essentially represents a form of chronic, progressive renal fibrosis for which there is no discernible cause. Often presenting with or eventually manifesting the nephrotic syndrome, this disease is increasing in incidence in both children and adults. Therapy continues to be a challenge, although some patients clearly respond to corticosteroids or cyclosporine with a decrease in, or remission of, proteinuria. A favorable response is associated with a decreased likelihood of progression to kidney failure. Given our clinical experience and recent advances in understanding the genetics of FSGS, a stochastic model of disease pathogenesis can be proposed.

Pretransplant evaluation of renal transplant candidates

Kidney transplantation should be strongly considered for all medically suitable patients with chronic and end-stage renal disease (ESRD). Improvements in outcomes after renal transplantation have resulted in a more liberal selection of patients. High-risk category patients including human immunodeficiency virus (HIV)-positive, highly sensitized patients, T-cell positive cross-match, and ABO blood group-incompatible patients are now considered potential renal transplant candidates. Unfortunately, the demand for kidney transplants far exceeds the supply of available organs, causing a persistent increase in the number of patients on the waiting list with a parallel increase in the waiting time for a cadaveric kidney transplant. This has 2 major consequences. First, patients on the waiting list are getting sicker and older. Second, living donors have assumed increasing importance in renal transplantation. Pre-existing morbidities including malignancies, cardiovascular disease, infections, and coagulopathies should be extensively evaluated before proceeding to transplantation. Special attention should be given to cardiovascular risk factors because the leading cause of death after renal transplant is cardiovascular disease. A full immunologic evaluation with ABO blood group determination, human leukocyte antigen (HLA) typing, screening for antibody to HLA phenotypes, and cross-matching need to be gathered before transplantation to avoid antibody-mediated hyperacute rejection or to proceed with specific protocols in highly sensitized or in positive T-cell cross-match patients. With the increased rate of donation from living donors, regular follow-up evaluation of kidney donors is recommended to detect hypertension or proteinuria in those who may develop it.

De novo minimal change disease associated with reversible post-transplant nephrotic syndrome. A report of five cases and review of literature

Nephrotic syndrome (NS) is frequent in renal transplant recipients and may be related to a large variety of glomerular lesions. In some of these cases, the transplant biopsy showed no significant glomerular changes and the NS was reversible, but the primary renal disease was not minimal change disease (MCD), suggesting that MCD may develop de novo in renal transplant setting. Knowledge of this entity, however, is limited. Among 67 cases of post-transplant NS encountered in a 12-yr period, five were found to be associated with de novo MCD. A critical review of the literature revealed nine additional cases of de novo MCD. The data from these 14 cases show that patients with de novo MCD had a large variety of primary renal diseases but MCD or focal segmental glomerulosclerosis was not among them. Eight of the 14 transplanted kidneys (60%) were from living related donors, suggesting this as a risk factor. Nephrotic range proteinuria (3-76 g/d) developed immediately or shortly after transplantation (within 4 months for all reported cases, except for one at 24 months). The serum creatinine when NS was first diagnosed was normal or mildly elevated, but acute renal failure occurred in three patients. On biopsy, the glomeruli were normal or, more frequently, displayed mild, focal segmental mesangial sclerosis, hypercellularity, deposition of IgM/C3, or accumulation of mononuclear inflammatory cells in some glomerular capillaries. The tubulointerstitial compartment was normal in cases with normal renal function; displayed mild acute and/or chronic rejection that correlated with a mildly elevated serum creatinine; or showed acute changes including acute rejection, acute tubular necrosis, or acute cyclosporin A toxicity, which accounted for both acute renal failure at presentation and its subsequent reversibility. Under various treatments, including increased steroids, angiotensin converting enzyme inhibitors, calcium channel blockers and angiotensin receptor blockers, sustained remission of NS was achieved in 13 cases, within a year (0.5-12 months) in 10 and later (24, 34 and 98 months, respectively) in three. In the remaining case, the patient died of septic shock 2 months after transplantation. After remission of the NS, the grafts functioned well without or with minimal proteinuria for several years. De novo MCD has characteristic clinical and pathologic features. It represents an important but hitherto underemphasized cause of post-transplant NS, which is potentially reversible and does not adversely affect the renal transplants.

New insights in chronic allograft rejection

Chronic allograft nephropathy remains the main cause of renal graft failure. Immunologic mechanisms seem mostly responsible for the injury and subsequent fibrogenic tissue response while nonimmune mechanisms act mostly as progression factors. In this article, these factors are reviewed along with the changes that take place in the graft and new insights into possible therapeutic strategies.

Acute rejection presenting as nephrotic syndrome

BACKGROUND

Early diagnosis and treatment of acute rejection is important to prevent continued renal injury. Acute rejection most commonly presents with asymptomatic rise in serum creatinine. Proteinuria associated with acute rejection is well established; however, there is limited documentation of the presentation of acute rejection as nephrotic syndrome in the literature.

METHODS AND RESULTS

We report a renal transplant patient who presented with early onset nephrotic syndrome without change in serum creatinine, whose allograft biopsy confirmed acute glomerulitis and vascular rejection. Treatment of the acute rejection was accompanied by resolution of the nephrotic syndrome. A second episode of acute rejection was also manifested as nephrotic range proteinuria.

CONCLUSION

The nephrotic syndrome in early post-transplantation period should prompt a work-up for acute rejection even in the absence of the common findings of this complication.

Recurrent and de novo glomerular disease after renal transplantation: a report from Renal Allograft Disease Registry (RADR)

INTRODUCTION

Short-term and long-term results of renal transplantation have improved over the past 15 years. However, there has been no change in the prevalence of recurrent and de novo diseases. A retrospective study was initiated through the Renal Allograft Disease Registry, to evaluate the prevalence and impact of recurrent and de novo diseases after transplantation.

MATERIALS AND METHODS

From October 1987 to December 1996, a total of 4913 renal transplants were performed on adults at the Medical College of Wisconsin, University of Cincinnati, University of California at San Francisco, University of Louisville, University of Washington, Seattle, and Washington University School of Medicine. The patients were followed for a minimum of 1 year. A total of 167 (3.4%) cases of recurrent and de novo disease were diagnosed by renal biopsy. These patients were compared with other patients who did not have recurrent and de novo disease (n=4746). There were more men (67.7% vs. 59.8%, P<0.035) and a higher number of re-transplants (17% vs. 11.5%, P<0.005) in the recurrent and de novo disease group. There was no difference in the rate of recurrent and de novo disease according to the transplant type (living related donor vs. cadaver, P=NS). Other demographic findings were not significantly different. Common forms of glomerulonephritis seen were focal segmental glomerulosclerosis (FSGS), 57; immunoglobulin A nephritis, 22; membranoproliferative glomerulonephritis (GN), 18; and membranous nephropathy, 16. Other diagnoses include: diabetic nephropathy, 19; immune complex GN, 12; crescentic GN (vasculitis), 6; hemolytic uremic syndrome-thrombotic thrombocytopenic purpura (HUS/TTP), 8; systemic lupus erythematosus, 3; Anti-glomerular basement membrane disease, 2; oxalosis, 2; and miscellaneous, 2. The diagnosis of recurrent and de novo disease was made after a mean period of 678 days after the transplant. During the follow-up period, there were significantly more graft failures in the recurrent disease group, 55% vs. 25%, P<0.001. The actuarial 1-, 2-, 3-, 4, and 5-year kidney survival rates for patients with recurrent and de novo disease was 86.5%, 78.5%, 65%, 47.7%, and 39.8%. The corresponding survival rates for patients without recurrent and de novo disease were 85.2%, 81.2%, 76.5%, 72%, and 67.6%, respectively (Log-rank test, P<0.0001). The median kidney survival rate for patients with and without recurrent and de novo disease was 1360 vs. 3382 days (P<0.0001). Multivariate analysis using the Cox proportional hazard model for graft failure was performed to identify various risk factors. Cadaveric transplants, prolonged cold ischemia time, elevated panel reactive antibody, and recurrent disease were identified as risk factors for allograft failure. The relative risk (95% confidence interval) for graft failure because of recurrent and de novo disease was 1.9 (1.57-2.40), P<0.0001. The relative risk for graft failure because of posttransplant FSGS was 2.25 (1.6-3.1), P<0.0001, for membranoprolifera. tive glomerulonephritis was 2.37 (1.3-4.2), P<0.003, and for HUS/TTP was 5.36 (2.2-12.9), P<0.0002. There was higher graft failure (64.9%) and shorter half-life (1244 days) in patients with recurrent FSGS.

CONCLUSION

In conclusion, recurrent and de novo disease are associated with poorer long-term survival, and the relative risk of allograft loss is double. Significant impact on graft survival was seen with recurrent and de novo FSGS, membranoproliferative glomerulonephritis, and HUS/TTP.

Chronic allograft nephropathy: An update

Chronic allograft nephropathy is the most prevalent cause of renal transplant failure in the first post-transplant decade, but its pathogenesis has remained elusive. Clinically, it is characterized by a slow but variable loss of function, often in combination with proteinuria and hypertension. The histopathology is also not specific, but transplant glomerulopathy and multilayering of the peritubular capillaries are highly characteristic. Several risk factors have been identified, such as advanced donor age, delayed graft function, repeated acute rejection episodes, vascular rejection episodes, and rejections that occur late after transplantation. A common feature of chronic allograft nephropathy is that it develops in grafts that have undergone previous damage, although the mechanism(s) responsible for the progressive fibrosis and tissue remodeling has not yet been defined. Hypotheses to explain chronic allograft nephropathy include the immunolymphatic theory, the cytokine excess theory, the loss of supporting architecture theory, and the premature senescence theory. The most effective option to prevent chronic allograft nephropathy is to avoid graft injury from both immune and nonimmune mechanisms.

De novo collapsing glomerulopathy in renal allografts

BACKGROUND

Collapsing glomerulopathy is a recently described form of glomerular injury characterized by capillary collapse and visceral epithelial hypercellularity associated with nephrotic range proteinuria and a rapid, progressive decline in renal function. The lesion has rarely been described in allografts.

METHODS

We reviewed 892 allograft biopsies from a population of 1079 recipients who received renal transplants between 1978 and 1996.

RESULTS

Five cases of de novo collapsing glomerulopathy were identified (0.6% of biopsies; 3.2% since 1993). None occurred before 1993. The patients were 31 to 66 years of age and they presented 6 to 25 months after transplantation. The 24-hr urinary protein ranged from 1.8 to 11.8 g. All patients and donors were negative for the human immunodeficiency virus and had no risk factors for human immunodeficiency virus infection. Diffuse or focal, global or segmental collapse of glomerular capillaries, swelling and hypercellularity of the visceral epithelium, hyaline arteriolosclerosis, and interstitial fibrosis were characteristic histologic features. Two cases had concomitant glomerular immune complex deposits. Progressive decline in allograft function occurred within 2-24 months after diagnosis, culminating in return to dialysis in all patients.

CONCLUSION

Collapsing glomerulopathy can arise in renal allografts as a de novo disease. Although its pathogenesis remains to be clarified, it is important to distinguish this lesion in allografts as it can be associated with rapidly progressive graft failure.

Focal segmental glomerulosclerosis

Over the last 2 decades, we have learnt that focal segmental glomerulosclerosis (FSGS) is a ubiquitous phenomenon underlying the progressive deterioration of many different types of renal diseases in both pediatric and adult populations. FSGS may also be the primary renal lesion, whether in new disease entities such as glycogen storage disease and human immunodeficiency virus infection, or in idiopathic FSGS. Although the mechanism which triggers the development of primary FSGS still remains unknown, laboratory and clinical studies have identified several key pathophysiological events leading to end-stage renal disease. While therapeutic modalities have not changed remarkably, a recent study, although uncontrolled, demonstrated an impressive efficacy of intravenous steroid pulse therapy in inducing remission. Nevertheless, it remains largely unknown whether such a forced remission decreases the overall risk of developing chronic renal failure. Studies have revealed an important pathophysiological role of angiotensin and the therapeutic efficacy of angiotensin converting enzyme inhibitors in progressive loss of renal function in diseases where glomerulosclerosis is secondary; however, it remains to be verified whether these results hold true in primary FSGS. As a result of the improvement in allograft survival rate, the benefit of renal transplant outweighs the risk of recurrence of FSGS, hence transplantation continues to be a vital therapy for FSGS patients who have reached renal failure. Thus, FSGS is not one disease, but rather a range of lesions seen in many settings. The type of lesions and the patient's unique genetic factors contribute to prognosis, and also may dictate choice of optimum therapy.

Chronic renal transplant loss

Chronic rejection results from recurrent episodes of subclinical or clinically evident acute rejection, with or without involvement of chronic rejection-specific allogeneic immune mechanisms. The tissue damage occurs over a prolonged period of time, which allows the emergence of antigen-independent tissue repair mechanisms and intrarenal adaptations in response to progressive loss of renal mass (Fig. 1). The combination of these mechanisms leads, very likely, to the tissue remodeling of chronic rejection. The heterogeneous expression of chronic rejection may result from different types and specificities of allogeneic immune reactions as well as different contributions of antigen-independent factors that modulate the antigen-dependent tissue responses to injury. The extent to which these mechanisms participate in the overall picture is presently unknown as immunological parameters are not measured routinely in the follow-up of patients with chronic graft dysfunction. Furthermore, some grafts may undergo tissue remodeling as a consequence of predominantly antigen-independent mechanisms. Therefore, the term chronic allograft dysfunction may clinically be preferable over chronic rejection to describe the gradual decline in graft function months or years after transplantation in the absence of a well-defined mechanism or an accepted treatment.

Living-related donor transplants should be performed with caution in patients with focal segmental glomerulosclerosis

The success rates of living-related donor (LRD) transplants are clearly superior to those obtained with cadaver donors. However, caution should be exercised when considering LRD transplantation for a condition which has an increased chance of recurring after transplantation and causing ultimate graft failure. The recurrence rate of focal segmental glomerulosclerosis (FSGS) in the allograft is 20%-40%, with graft failure resulting in 40%-50% of these cases. However, these figures may be an underestimation of the true rate of recurrence of FSGS. Once a first transplant fails due to recurrent disease, the risk of recurrence in the second transplant approaches 80%. Subgroups of patients at high risk for recurrence have been identified. In patients not at high risk for recurrent FSGS, the use of a LRD should be considered, provided that the donor and recipient and their families have been informed that the disease may recur and lead to graft failure. In patients at high risk for recurrence, a LRD transplant should be avoided. Hopefully, future development of a simple and reliable test to predict the likelihood of recurrence will enable us to counsel and advise our patients with FSGS about the wisdom or dangers of proceeding with a LRD transplant.

Nephron supply is a major determinant of long-term renal allograft outcome in rats

The effects of augmenting the nephron supply on indices of allograft injury were assessed in a rat model of "chronic rejection." Orthotopic renal allotransplantation into unine-phrectomized rats was followed by excision (allograft-alone group) or preservation of the remaining native kidney (allograft+native kidney group) such that the total kidney complement was either the allograft alone, or the allograft plus one retained native kidney. After 18 wk, values for GFR (1.85 +/- 0.3 ml/min) and kidney weights (2.3 +/- 0.2 g) in allograft-alone rats were far in excess of corresponding values in the allograft of allograft+native kidney rats (0.88 +/- 0.1 ml/min and 1.1 +/- 0.5 g, respectively). Proteinuria (35 +/- 2 mg/d) and allograft glomerulosclerosis (24 +/- 8%) also characterized allograft-alone but not allograft+native kidney rats, in whom glomerular structure (allograft glomerulosclerosis, 4 +/- 1%; native kidney glomerulosclerosis, 0%) and glomerular functional integrity (proteinuria 7 +/- 0.7 mg/d) were well preserved. Thus, the observed allograft protection derived from the presence of a retained recipient native kidney supports the hypothesis that a single renal allograft contains insufficient nephrons to prevent progressive renal injury, implicating nephron supply as a major determinant of long-term allograft outcome.

Recurrent diseases in the kidney transplant

Virtually all diseases affecting the native kidney recur in the kidney transplant with the exception of Alport syndrome, polycystic kidney disease, hypertension, chronic pyelonephritis, and chronic interstitial nephritis. Fortunately, in the majority of patients, recurrence of the original disease has minimal clinical impact, with only approximately 5% of all graft loss occurring as a result of recurrent disease. The primary renal diseases that commonly recur include membranoproliferative glomerulonephritis type II, IgA nephropathy, and focal and segmental glomerular sclerosis. The most common systemic disease that recurs is diabetic nephropathy. Living-related transplantation should be used with caution in patients with the hemolytic uremic syndrome, recurrent focal and segmental glomerular sclerosis, and membraneous glomerulonephritis. Fabry disease and primary hyperoxaluria type I are no longer absolute contraindications to kidney transplantation.

Chronic rejection of rat aortic allografts. III. Synthesis of major eicosanoids by vascular wall components and effect of inhibition of the thromboxane cascade

We have previously demonstrated that rat aortic allografts from the DA (RT1a) to the WF (RT1v) strain develop chronic arteriosclerotic changes in the vascular wall after a short spontaneously reversible acute rejection episode. These changes, which are lacking in syngeneic DA-to-DA control grafts, are virtually identical with those observed in human allografts during chronic rejection. In this study we have investigated whether eicosanoids are involved in the generation of arteriosclerotic changes. Incubation of aortic wall rings in vitro and immunochemical assays demonstrated that the arteriosclerotic allografts synthesize significantly more thromboxane B2 (TxB2) but not 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha) or leukotriene B4. The increased synthesis of TxB2 in the allografts persisted for at least 5 months after transplantation. Separate incubation of the two major components of the vascular wall, after microdissection of the intima and (media plus) adventitia, demonstrated that most of the synthesis of TxB2 during chronic rejection was due to the outer layer of aorta, presumably the inflammatory cells of the adventitia. In contrast, most of the 6-keto-PGF1 alpha was synthesized by the inner layer of the aorta, presumably the endothelial cells and the smooth muscle cells of the intima. Administration of 1 mg.kg-1 x day-1 of a specific TxA2 receptor inhibitor, GR32191B, to the recipient rat reduced the proliferative response of inflammatory cells in the adventitia by 30%, as detected by in vivo tritiated-thymidine (3H-TdR) labeling and autoradiography, but did not reduce the proliferative response of smooth muscle cells in the media and intima.(ABSTRACT TRUNCATED AT 250 WORDS)

Recurrence of disease following renal transplantation

The diagnosis of recurrent renal disease after transplantation is dependent on an accurate and complete diagnosis of the initial cause of renal failure and a similar determination of the cause of graft failure. To be classified as recurrent, the disease in the renal graft must be identical to that seen in the native kidneys. Recurrence of disease accounts for less than 2% of all graft failures, but the overall incidence of recurrent disease is probably 5 to 10 times more common. The most frequent cause of recurrent disease is glomerulonephritis, which was first recognized to recur soon after renal transplantation was introduced. It was then recognized that a variety of metabolic disorders would recur, but it has taken 25 years of experience for a clear picture to emerge of recurrence in most conditions. No initial cause of renal failure poses a contraindication to at least one attempt at transplantation, although with Fabry's disease and oxalosis, a special assessment of the risks for the individual recipient is warranted. In some patients, experience has shown the need for a delay in the commitment to transplantation (eg, in those with anti-glomerular basement membrane [GBM] antibody glomerulonephritis or Henoch Schonlein purpura), the need for the choice of a particular immunosuppressive regimen (eg, in hemolytic uremic syndrome [HUS]), the need for avoidance of primary nonfunction (eg, in oxalosis), and the desirability of avoiding live kidney donation (eg, in heterozygote donors in Fabry's disease, high-risk recipients with focal glomerulosclerosis, and in recipients with HUS). Probably all types of glomerulonephritis recur, but with great variation in frequency and severity. In some forms of glomerulonephritis, recurrence may be frequent and definite on histopathological criteria but may only have a minor clinical expression (eg, dense deposit disease, anti-GBM antibody glomerulonephritis, IgA nephropathy), but in others, recurrence is less predictable yet it is clearly associated with premature graft failure (eg, focal glomerulosclerosis, membranous nephropathy). A common theme emerging is that where the initial glomerulonephritis is aggressive and causes kidney failure over a short time, recurrence is more likely, and when present, it will lead to graft failure with an increased frequency. Clinical manifestations, the frequency of recurrence, and the prognosis of the graft are now identified for most conditions. Unexpected observations have included the rarity of recurrent systemic lupus erythematosus (SLE), the immediate return of heavy proteinuria in focal glomerulosclerosis, and the predictable return of dense deposit disease.(ABSTRACT TRUNCATED AT 400 WORDS)

De novo focal glomerulosclerosis after kidney transplantation

A transplanted kidney in a patient developed focal and segmental glomerulosclerosis, associated with severe systemic hypertension, proteinuria, progressive azotemia, and allograft hypertrophy. A pediatric kidney with two main arteries was used, and occlusion of the artery supplying the upper pole resulted in infarction of this portion of the allograft. Because other known factors predisposing to focal sclerosis were absent, it is postulated that renal hemodynamic changes associated with reduction in functioning renal mass, attended by striking stimuli for renal hypertrophy, resulted in progressive damage. The implications of these concepts are discussed in relation to the progression of renal diseases.