Global evolutionary trend of the prevalence of primary glomerulonephritis over the past three decades.

OBJECTIVE: The prevalence of primary glomerulonephritis in Singapore is compared with that of 28 other countries to review changing trends in the evolution of primary glomerulonephritis in Asia and other countries. METHOD: 2,586 renal biopsies in Singapore over the past 3 decades were reviewed and compared with data from 28 other countries. RESULTS: In the 1st decade most Asian countries have mesangial proliferative glomerulonephritis as the most common form of primary glomerulonephritis, and in the 3rd decade there has been a dramatic increase in focal and segmental glomerulosclerosis reflecting aging and obesity in keeping with more developed countries. IgA nephritis remains the commonest glomerulonephritis in many countries. Membranous glomerulonephritis continues to be more prevalent in Western countries while mesangial proliferative glomerulonephritis remains prevalent in many Asian countries. CONCLUSION: Apart from geographical and genetic influences, socioeconomic factors may play a role in the evolution of the biopsy pattern in some countries. Worldwide, the prevalence of focal segmental glomerulosclerosis continues to increase. In third world countries some of the commoner forms of glomerulonephritis are related to infections, in contrast to developed countries where the antigenic exposure may be related to diet, allergens and other industrial agents.

Factors associated with proteinuria in renal transplant recipients treated with sirolimus.

Although sirolimus (SRL) use in renal allograft recipients (RTX) is associated with improved renal function, proteinuria develops in a significant proportion. 48 SRL-treated RTX were evaluated for development of proteinuria and stratified by level of proteinuria after SRL therapy. The Proteinuria Group (n = 25, 52.1%) had new-onset proteinuria or >25% increase in proteinuria following SRL conversion; the Nonproteinuria Group had stable proteinuria <0.5 g/day throughout. There was a higher proportion of male RTX and female donors to male recipients in the Proteinuria Group, (24% vs. 10%, P = 0.008). Calcineurin inhibitor- and statin usage were significantly higher in the Nonproteinuria Group (8% vs. 17%, P = 0.046; 28% vs. 83%, P < 0.001 respectively) whereas biopsy-proven acute rejection was higher in the Proteinuria Group (68% vs. 33%, P = 0.037). SDS-PAGE analysis of urine from 23 RTX in the Proteinuria Group demonstrated glomerular proteinuria in 100% and tubular proteinuria in 87%. While male gender and gender mismatch may impact on glomerular proteinuria through inadequate nephron dose and subsequent hyperfiltration, concurrent cyclosporine use may mitigate the development of proteinuria in SRL-treated patients, through afferent arteriolar vasoconstriction. Glomerular injury occurring following acute rejection may further contribute to glomerular proteinuria. Statins, through their anti-inflammatory and anti-fibrotic effects, may protect against development of proteinuria.

High dose Losartan and ACE gene polymorphism in IgA nephritis.

Background/aims Several studies have reported varying results of the influence of ACE gene on ACEI/ARB therapy. The efficacy of high dose ARB and its influence on ACE gene have not been explored. This is a 6 year randomised trial in IgA nephritis comparing high dose ARB (Losartan 200 mg/day) with normal dose ARB (Losartan 100 mg/day), normal dose ACEI (20 mg/day) and low dose ACEI (10 mg/day). Results Patients on high dose ARB had significantly lower proteinuria, 1.0 +/- 0.8 gm/day compared to 1.7 +/- 1.0 g/day in the other groups (P = 0.0005). The loss in eGFR was 0.7 ml min(-1)year(-1) for high dose ARB compared to 3.2-3.5 ml min(-1)year(-1) for the other three groups (P = 0.0005). There were more patients on high dose ARB with improvement in eGFR compared to other three groups (P < 0.001). Comparing patients with the three ACE genotypes DD, ID and II, all three groups responded well to therapy with decrease in proteinuria (P < 0.002). Only those on low dose ACEI (10 mg/day) with the I allele had increased in ESRF (P = 0.037). Conclusion High dose ARB is more efficacious in reducing proteinuria and preserving renal function when compared with normal dose ARB and ACEI, and also obviates the genomic influence of ACE gene polymorphism on renal survival.

Overexpression of interleukin-13 induces minimal-change-like nephropathy in rats.

IL-13 has been implicated in the pathogenesis of minimal-change nephrotic syndrome. This study aimed to investigate the role of IL-13 on the development of proteinuria and expression of podocyte-related genes that are associated with nephrotic syndrome. IL-13 was overexpressed in Wistar rats through transfection of a mammalian expression vector cloned with the rat IL-13 gene, into the quadriceps by in vivo electroporation. Serum IL-13, albumin, cholesterol, and creatinine and urine albumin were measured serially. Kidneys were harvested after day 70 for histology and electron microscopy. Glomerular gene expression of nephrin, podocin, dystroglycan, B7-1, and IL-13 receptor subunits were examined using real-time PCR with hybridization probes and expressed as an index against beta-actin. Protein expression of these molecules was determined by immunofluorescence staining. The IL-13-transfected rats (n = 41) showed significant albuminuria, hypoalbuminemia, and hypercholesterolemia when compared with control rats (n = 17). No significant histologic changes were seen in glomeruli of IL-13-transfected rats. However, electron microscopy showed up to 80% of podocyte foot process fusion. Glomerular gene expression was significantly upregulated for B7-1, IL-4Ralpha, and IL-13Ralpha2 but downregulated for nephrin, podocin, and dystroglycan. Immunofluorescence staining intensity was reduced for nephrin, podocin, and dystroglycan but increased for B7-1 and IL-4Ralpha in IL-13-transfected rats compared with controls. In conclusion, these results suggest that IL-13 overexpression in the rat could lead to podocyte injury with downregulation of nephrin, podocin, and dystroglycan and a concurrent upregulation of B7-1 in the glomeruli, inducing a minimal change-like nephropathy that is characterized by increased proteinuria, hypoalbuminemia, hypercholesterolemia, and fusion of podocyte foot processes.

Long term outcome of renal allografts in patients with immunoglobulin A nephropathy.

Recurrent glomerular disease is an important cause of late allograft loss in renal transplant recipients. Immunoglobulin A nephropathy (IgAN) is a leading cause of end-stage renal disease (ESRD) worldwide and its recurrence has been reported in allografts. The present study examined outcomes following renal transplantation (RTX) in 101 patients with ESRD due to biopsy-proven IgAN, in comparison to non-IgA patients, and evaluated the incidence of recurrence. The study population (mean age 34.8 +/- 7.7 years; males 62.2%; Chinese 88.3%) underwent RTX under CsA immunosuppression between November 1984 and December 2004; as two patients underwent retransplantation during the study period, 103 allografts (56.3% cadaveric) were included for retrospective analysis. At time of analysis on 1 January 2005, 78 (75.7%) renal allografts (IgAN RTX) were functioning, of which 51 (49.5%) had normal serum creatinine, 27 (26.2%) had chronic allograft dysfunction, while 25 had graft losses, either due to patient death with functioning grafts (5.8%) or withdrawal to dialysis (18.5%). Persistent microscopic haematuria, not attributable to other causes or proteinuria > 1 g/day occurred in 42.7% and 13.6% of allografts respectively. Of 29 allografts biopsied for evaluation of proteinuria and/or renal dysfunction post-RTX, 8 (27.6%) had IgAN (overall histological recurrence, 7.8%). Of these, three had graft loss due to recurrent IgAN, three had elevated serum creatinine, while two had normal serum creatinine. Overall five and ten year patient survivals for IgAN RTX were 95.3% and 82.2%, and five and ten year actuarial graft survivals were 82.3% and 67.8% respectively. Five and ten year patient and graft survivals for IgAN RTX were not significantly different from that for non-IgAN RTX. In summary, RTX patients with IgAN have a low incidence of documented histological recurrence and recurrence contributing to graft loss occurs in only 2.9%. These results suggest that RTX is an excellent modality of renal replacement therapy in this population.

3rd College of Physicians' lecture--translational research: From bench to bedside and from bedside to bench; incorporating a clinical research journey in IgA nephritis (1976 to 2006).

Translational research (TR) can be defined as research where a discovery made in the laboratory (bench) can be applied in the diagnosis, treatment or prevention of a disease. Examples of medical discoveries contributing to translational medicine (TM) include the isolation of insulin by Banting (Nobel Laureate, 1923), the discovery of penicillin by Alexander Fleming (Nobel Laureate, 1945) and recently the discovery of the role of bacterium Helicobacter pylori in the causation of gastritis and peptic ulcer by Marshall and Warren (Nobel Laureates, 2005). Clinical research (CR) would be a more appropriate term for the bulk of research work undertaken by doctors. CR embraces both clinical based and laboratory-based research. The terminology "bedside to bench" applies more to CR as opposed to "bench to bedside" in the case of TR. But regardless of who does it, as long as the discovery can be translated to the bedside and results in improvement in patient care it can be considered a contribution to TM. Our work spans a 30-year period, involving laboratory-based research, clinical trials and genomics of IgA nephritis (Nx). This is a series of work to elucidate the pathogensis and therapy of IgANx. Plasma beta-thromboglobulin (BTG) an in-vivo index of platelet aggregation and anti-thrombin III increase due to a constant thrombogenecity resulting from platelet degranulation formed the basis for anti-platelet and low-dose warfarin therapy. A study of the natural history of IgANx revealed 2 courses, a slowly progressive course with end-stage renal failure (ESRF) at 7.7 years and a more rapid course at 3.3 years. Triple therapy (cyclophosphamide, persantin and low-dose warfarin) delayed progression to ESRF by about 8 years and for some patients up to 20 years. Documentation of abnormal suppressor T cell function provided the basis for immune therapy. Four patterns of proteinuria were present in IgANx and it is the quality and not so much the quantity of proteinuria which determined the prognosis. Low molecular weight proteinuria was a bad prognostic marker. A controlled therapeutic trial using ACEI/ATRA showed that therapy decreases proteinuria, improves renal function and converts non-selective to selective proteinuria. Subsequent work confirmed that it was the ATRA, not the ACEI which contributed to improved renal function. Individual anti proteinuria response to ATRA varies depending on ACE gene polymorphism. We found that the II genotype of the ACE gene was renoprotective and patients with this genotype had significantly reduced incidence of ESRF compared to those with the DD genotype. Patients responsive to ATRA therapy can retard progression to ESRF by up to 32 years. Mild renal failure can be reversed with possible regression of glomerulosclerosis because of glomerular remodelling by ATRA.

Randomized trial of Alemtuzumab for prevention of graft rejection and preservation of renal function after kidney transplantation.

BACKGROUND: A randomized, multicenter, controlled trial was undertaken to evaluate the safety and efficacy of Alemtuzumab, a powerful lytic agent for both T and B lymphocytes, in the prophylaxis of rejection in renal transplantation (RTx). METHODS: Thirty patients were randomized to receive Alemtuzumab together with low-dose cyclosporine (CsA) monotherapy (CAMPATH, n = 20) or to full doses of CsA with azathioprine and corticosteroids (Standard, n = 10). CsA was administered at doses to achieve whole-blood trough CsA levels of 90 to 110 ng/mL and 180 to 225 ng/mL in CAMPATH and Standard groups, respectively. RESULTS: Per protocol, CsA trough levels were lower in patients assigned to CAMPATH post-RTx (median trough level of 119 vs. 166 ng/mL at 6 months, CAMPATH vs. Standard; 95% confidence interval, -92 to -34). At 6 months post-RTx, serum creatinine, graft and patient survivals, incidence of biopsy proven acute rejection (25% vs. 20%, CAMPATH vs. Standard), overall treatment failure, and severe and moderate infections were comparable. Whereas all patients receiving Standard therapy required maintenance corticosteroids at 6 months, of the 17 of 20 patients with functioning grafts in CAMPATH, 15 (88%, 95% confidence interval, 53%-97%) were steroid free. CONCLUSION: These results suggest that Alemtuzumab is an effective induction agent that permits low-dose steroid-free immunosuppression in RTx.