Going to war on COVID-19: Mobilizing an academic nephrology group practice

Aim

The COVID‐19 pandemic poses unprecedented operational challenges to nephrology divisions in every country as they cope with COVID‐19‐related kidney disease in addition to regular patient care. Although general approaches have been proposed, there is a lack of practical guidance for nephrology division response in a hospital facing a surge of cases. Here, we describe the specific measures that our division has taken in the hope that our experience in Singapore may be helpful to others.

Methods

Descriptive narrative.

Results

A compilation of operational responses to the COVID‐19 pandemic taken by a nephrology division at a Singapore university hospital.

Conclusion

Nephrology operational readiness for COVID‐19 requires a clinical mindset shift from usual standard of care to a crisis exigency model that targets best outcomes for available resources. Rapid multi‐disciplinary efforts that evolve flexibly with the local dynamics of the outbreak are required.

A valuable experience and operational response to COVID‐19 pandemic threat by a nephrology division at a Singapore university hospital. This article gives good example of shift of clinical mindset from usual standard of care to a crisis exigency model that targets best outcomes for available resources.

Projecting the Burden of Chronic Kidney Disease in a Developed Country and Its Implications on Public Health

BACKGROUND

Chronic Kidney Disease (CKD) is a major public health problem worldwide. There is limited literature on a model to project the number of people with CKD. This study projects the number of residents with CKD in Singapore by 2035 using a Markov model.

METHODS

A Markov model with nine mutually exclusive health states was developed according to the clinical course of CKD, based on a discrete time interval of 1 year. The model simulated the transition of cohorts across different health states from 2007 to 2035 using prevalence, incidence, mortality, disease transition, and disease detection rates.

RESULTS

From 2007 to 2035, the number of residents with CKD is projected to increase from 316,521 to 887,870 and the prevalence from 12.2% to 24.3%. Patients with CKD stages 1-2 constituted the largest proportion. The proportion of undiagnosed cases will decline from 72.1% to 56.4%, resulting from faster progression to higher CKD stages and its eventual detection.

CONCLUSION

By 2035, about one-quarter of the Singapore residents are expected to have CKD. National policies need to focus on primary disease prevention and early disease detection to avoid delayed treatment of CKD which eventually leads to end-stage renal disease.

Outcome of Living Donor Transplant Kidneys With Multiple Arteries

BACKGROUND

Living donor transplantation (LDT) using kidneys with multiple arteries (MA) has previously been reported to be associated with increased complications and poorer outcomes in recipients. The objective of this study was to investigate outcomes of LDT with MA at the National University Hospital of Singapore, an institution with modest kidney transplant volumes.

METHODS

From 2007 to 2014, a total of 109 consecutive living donor kidney transplantations were performed. Of the nephrectomies, 91% were left sided. A total of 19 cases involved MA, of which 7 with small polar vessels (<2 mm) were ligated and 12 were revascularized. Baseline characteristics and outcomes were comparable between donor-recipient pairs with MA and single artery (SA). Both groups had equivalent induction and maintenance immunosuppressive regimens.

RESULTS

Mean warm ischemia time (minutes) was similar for kidneys with MA and SA (4.3 ± 3.2 vs 3.9 ± 3.2, P = .38). Operative time (minutes) in the recipients was also equivalent (P > .05) for MA and SA (158 ± 39.2 and 145 ± 57.2, respectively). The MA kidney recipients had a lower estimated glomerular filtration rate (eGFR) on postoperative day 5 compared to SA (56.6 ± 24.2 vs 74.1 ± 35.9 mL/min/1.73 m(2), P = .058). However, eGFR at 1 year was the similar for both groups (64.9 ± 16.2 vs 66.4 ± 18.1 mL/min/1.73 m(2), respectively, P = .76). Delayed graft function rates were 5.6% and 6.6% for MA and SA, respectively (P = .9). There were no surgical complications for LDT recipients within the MA group. Patient and graft survival was 100% in the MA group compared with 98% in the SA group (P > .05).

CONCLUSIONS

With current surgical techniques, LDT with MA can achieve equally good functional outcomes at 1 year as SA kidneys, with minimal surgical complications.

Comparison of the preference-based EQ-5D-5L and SF-6D in patients with end-stage renal disease (ESRD)

OBJECTIVES

The objective of this study was to compare the performance of the 5-level EuroQol 5-dimension (EQ-5D-5L) and the Short Form 6-dimension (SF-6D) instruments in assessing patients with end-stage renal disease (ESRD) in Singapore.

METHODS

In a cross-sectional study, ESRD patients attending a tertiary hospital were interviewed using a battery of questionnaires including the EQ-5D-5L, the kidney disease quality of life instrument (KDQOL-36), and questions assessing dialysis history and socio-demographic characteristics. We reviewed patients' medical records for their clinical information. We assessed the construct validity of the EQ-5D-5L and SF-6D index scores and compared their ability to distinguish between patients differing in health status and the magnitude of between-group difference they quantified.

RESULTS

One hundred and fifty ESRD patients on dialysis (mean age, 60.1 years; female, 48.7%) participated in the study. Both EQ-5D-5L and SF-6D demonstrated satisfactory known-groups validity; the EQ-5D-5L was more sensitive to differences in clinical outcomes and the SF-6D was more sensitive to differences in health outcomes measured by KDQOL scales. The intraclass correlation coefficient between the measures was 0.36. The differences in the EQ-5D-5L index score for patients in better and worse health status were greater than those measured by the SF-6D index score.

CONCLUSIONS

Both EQ-5D-5L and SF-6D are valid instruments for assessing ESRD patients. However, the two preference-based measures cannot be used interchangeably and it appears that EQ-5D-5L would lead to more favorable cost-effectiveness results than SF-6D if they are used in economic evaluations of interventions for ESRD.

Hemodialysis versus Peritoneal Dialysis: A Comparison of Survival Outcomes in South-East Asian Patients with End-Stage Renal Disease

Background

Studies comparing patient survival of hemodialysis (HD) and peritoneal dialysis (PD) have yielded conflicting results and no such study was from South-East Asia. This study aimed to compare the survival outcomes of patients with end-stage renal disease (ESRD) who started dialysis with HD and PD in Singapore.

Methods

Survival data for a maximum of 5 years from a single-center cohort of 871 ESRD patients starting dialysis with HD (n = 641) or PD (n = 230) from 2005–2010 was analyzed using the flexible Royston-Parmar (RP) model. The model was also applied to a subsample of 225 propensity-score-matched patient pairs and subgroups defined by age, diabetes mellitus, and cardiovascular disease.

Results

After adjusting for the effect of socio-demographic and clinical characteristics, the risk of death was higher in patients initiating dialysis with PD than those initiating dialysis with HD (hazard ratio [HR]: 2.08; 95% confidence interval [CI]: 1.67–2.59; p<0.001), although there was no significant difference in mortality between the two modalities in the first 12 months of treatment. Consistently, in the matched subsample, patients starting PD had a higher risk of death than those starting HD (HR: 1.73, 95% CI: 1.30–2.28, p<0.001). Subgroup analysis showed that PD may be similar to or better than HD in survival outcomes among young patients (≤65 years old) without diabetes or cardiovascular disease.

Conclusion

ESRD patients who initiated dialysis with HD experienced better survival outcomes than those who initiated dialysis with PD in Singapore, although survival outcomes may not differ between the two dialysis modalities in young and healthier patients. These findings are potentially confounded by selection bias, as patients were not randomized to the two dialysis modalities in this cohort study.

Health-related quality of life of Asian patients with end-stage renal disease (ESRD) in Singapore

BACKGROUND

This study aimed to identify factors associated with the health-related quality of life (HRQOL) of multiethnic Asian end-stage renal disease (ESRD) patients treated with dialysis. The role of dialysis modality was also explored.

METHODS

Data used in this study were from two cross-sectional surveys of Singaporean ESRD patients on haemodialysis (HD) or peritoneal dialysis (PD). In both surveys, participants were assessed using the kidney disease quality of life (KDQOL) instrument and questions assessing socio-demographic characteristics. Clinical data including co-morbidity (measured by Charlson comorbidity index [CCI]), albumin level, haemoglobin level, and dialysis-related variables (e.g. dialysis vintage and dialysis adequacy) were retrieved from medical records. The 36-item KDQOL (KDQOL-36) was used to generate three summary scores (physical component summary [PCS], mental component summary [MCS] and kidney disease component summary [KDCS]) and two health utility scores (Short Form 6-dimension [SF-6D] and EuroQol 5-dimension [EQ-5D]). Linear regression analysis was performed to examine the association of factors with each of the HRQOL scale scores.

RESULTS

Five hundred and two patients were included in the study (mean age 57.1 years; male 52.4 %; HD 236, PD 266). Mean [standard deviation (SD)] PCS, MCS and KDCS scores were 37.9 (9.7), 46.4 (10.8) and 57.6 (18.1), respectively. Mean (SD) health utility score was 0.66 (0.12) for SF-6D and 0.60 (0.21) for EQ-5D. In multivariate regression analysis, factors found to be significantly associated with better HRQOL included: young (<45 years) or old age (>60 years), low CCI (<5), high albumin (≥37 g/l) and high haemoglobin (≥11 g/dl) with PCS; long dialysis vintage (≥3.5 years) with MCS; old age, Malay ethnicity and PD modality with KDCS; low CCI, high albumin and high haemoglobin with EQ-5D and high albumin with SF-6D.

CONCLUSIONS

Clinical characteristics are better predictors of HRQOL in ESRD patients than socio-demographics in Singapore. Dialysis modality has no impact on the health utility of those patients.

A necessary step toward kidney donor safety: the transition from locking polymer clips to transfixion techniques in laparoscopic donor nephrectomy

Donor safety is of paramount importance in addressing end-stage renal failure through living kidney transplantation. The United States Food and Drug Administration (FDA) issued a Class II recall on the use of Hem-o-lok (Teleflex, Limerick, Pennsylvania, United States) polymer clips on the renal artery in laparoscopic donor nephrectomy (LDN) in June 2006 following 3 reported cases of donor deaths secondary to slipped ligature. The National University Hospital of Singapore made the transition regarding hilar control in minimally invasive donor nephrectomy, from using polymer and titanium clips to transfixion techniques (pure or hand-assisted laparoscopic) via laparoscopic staples or intracorporeal suturing, respectively. This study assessed safety during the transition in arterial transfixion techniques in minimally invasive donor nephrectomy for both donors and recipients. Forty-five consecutive kidney donors underwent donor nephrectomy over a 2-year period starting from June 2010. A total of 37 donors who underwent LDN (pure laparoscopic or hand-assisted laparoscopic) were included in the analysis. Of the 37 patients, 23 kidney donors had renal arterial control using Hem-o-lok while 14 patients from November 2011 onward underwent transfixion of the renal artery. The 2 groups of donor who underwent renal arterial control by either clips ligature or transfixion technique were comparable. The outcomes for the recipients in each group were similar with no statistical difference between postoperative creatinine level, incidence of delayed graft function, or graft survival at 1 year. We conclude that the transition in renal arterial control technique to transfixion techniques in LDN in line with FDA recommendation is feasible and affords equivalent donor and recipient outcomes.

Native renal cysts and dialysis duration are risk factors for renal cell carcinoma in renal transplant recipients

Urinary tract cancers are the third most common cancers in renal transplant recipients (RTX). This study examined the impact of dialysis duration and native renal cyst(s) (NRC) on renal cell carcinoma (RCC) occurrence among 1036 RTX followed-up from 1995 to July 2007. Abdominal ultrasonography was planned within 1-month of transplant, then every 5 years, or 2 years if renal cysts developed. Based on presence and time of development of NRC, RTX were grouped into those with no (No-NRC), new (New-NRC), preexisting (Pre-NRC) and time-indeterminate NRC (TI-NRC). Ten asymptomatic RTX were diagnosed with RCC at a median of 5.8 years posttransplant and had 5-year graft and patient survivals of 90% and 100%, respectively, following appropriate therapy. RCC occurred only in Pre-NRC and TI-NRC who had significantly longer dialysis duration than No- or New-NRC (6.7 ± 3.9 and 3.3 ± 3.2 vs. 2.7 ± 3.1 and 2.6 ± 2.4 years, respectively). These results suggest that NRC and increased dialysis duration are risk factors for RCC posttransplant. Since early treatment of RCC gives excellent outcomes, regular ultrasonography performed within a month of transplantation, then every 5 years for those without cysts and every 2 years for those with cysts for early detection of RCC is recommended.

Expression of EBV latent antigens, mammalian target of rapamycin, and tumor suppression genes in EBV-positive smooth muscle tumors: clinical and therapeutic implications

PURPOSE

EBV-positive smooth muscle tumor (EBV+SMT) is a rare disease with no established therapy. We describe the largest single institution analysis in renal transplant recipients. It aims to define its clinical features and determine the expression of EBV latent genes as well as key molecular pathways.

EXPERIMENTAL DESIGN

Patients with EBV+SMT were identified from the Singapore General Hospital Renal Transplant Registry database. These tumors were investigated for expression of EBV latent genes with Southern blots, EBV latent antigens, mammalian target of rapamycin (mTOR), Akt, p70 S6 kinase, and vascular endothelial growth factor using immunohistochemistry, as well as methylation status of cancer-related genes using methylation-specific PCR.

RESULTS

Eight were found to be EBV+SMT in 1,123 transplant patients. All displayed indolent clinical courses and were unresponsive to immunosuppression reduction. Complete tumor regression was seen in one patient following administration of sirolimus. These tumors display the full range of known EBV latent genes. Immunohistochemistry with total and phosphorylated mTOR and Akt were positive for all patients, and vascular endothelial growth factor was positive in 25% of patients, suggesting activation of the mTOR/Akt pathway. Methylation of RASSF1A was found in all tissue samples, whereas promoter hypermethylation of RARbeta, GSTP1, DAPK, and p14 was observed in some samples.

CONCLUSIONS

Our results suggest that these tumors display a EBV type III latency pattern. The mTOR pathway is also activated. EBV may play a role in silencing RASSF1A. EBV-specific immunotherapy, mTOR inhibitors, and demethylating agents are possible therapeutic options in this disease.

Renal transplantation in Singapore

INTRODUCTION

Renal transplantation is the best treatment for kidney failure. As the demand far exceeds the supply, various legislative measures have been put into place in Singapore to increase kidney transplant rates. This paper evaluates the impact of these measures and reports on the outcomes for kidney transplant recipients in Singapore.

MATERIALS AND METHODS

Patient demographics, recipient and donor characteristics, and co-morbidities occurring in incident transplant patients were extracted from Singapore Renal Registry (SRR) Reports from 1997 to 2006, tabulated and summarised. Graft and patient survivals data, which were calculated by Kaplan-Meier analysis until return to dialysis/pre-emptive renal re-transplant or patient death respectively, were extracted from SRR Reports. Published data from the United States Renal Data System (USRDS) and Organ Procurement and Transplantation Network (OPTN) were used for comparisons with data from the SRR.

RESULTS

The introduction of the Human Organ Transplant Act increased the rate of deceased donor (DD) kidney transplants from 4.7 per year from 1970 to 1988, to 41.4 per year from 1988 to 2004. In 2006, the overall DD and living donor (LD) rate for kidney transplants performed locally for Singaporeans and permanent residents of Singapore was 22.6 per million population (pmp); taking into account overseas kidney transplants, the kidney transplant rate was 33.0 pmp. One and 5-year graft survivals for local LD and DD transplanted between 1999 and 2006, as reported by the SRR, were 98.1% and 95.3% versus 88.9% and 81.3%, respectively (P <0.001). Patient survivals at 1 and 5 years were likewise significantly better for LD versus DD (99.4% and 96.6% vs. 96% and 89.1%, respectively; P = 0.005).

CONCLUSIONS

The local kidney transplant rates were lower than those reported by the USRDS for the USA, Spain, Norway and Australia but higher than other Asian countries. While 1-year outcomes for transplants reported to the SRR were similar to that reported by the OPTN, 5-year survivals were significantly higher, possibly due to the selection of patients with fewer comorbidities for kidney transplantation in Singapore. These results suggest that while outcomes are excellent, there is much more to be done to increase kidney transplantation rates in Singapore so as to meet the needs of end-stage renal failure patients in the country.

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.

Significant impact of gene polymorphisms on tacrolimus but not cyclosporine dosing in Asian renal transplant recipients

Calcineurin inhibitors (CNI) are metabolized by cytochrome-P4503A (CYP3A) enzymes and extruded into the intestinal lumen by the drug efflux pump, P-glycoprotein (P-gp). The impact of single nucleotide polymorphisms (SNPs) of genes encoding CYP3A5 and P-gp on CNI dosing was examined among Asian renal transplant recipients. Frequencies of CYP3A5*1 versus *3 and MDR1-C3435T were correlated with tacrolimus (TAC) and cyclosporine (CSA) concentration-to-dose (C/D) ratios. Among 82 recipients (49% male; 88% Chinese), the majority were CYP3A5 expressors (*1*1 and *1*3, 11% and 40%, respectively) and 49% were nonexpressors (*3/*3). The prevalence of MDR-1-C3435T variants was 3435CC (41%), 3435CT (46%), and 3435TT (13%). Among 18 TAC-treated recipients, all receiving Diltiazem (DTZ), the median C/D ratio was lower for CYP3A5 *1/*1 versus *1/*3 versus *3/*3 (1.9, 4.6, and 13.5 ng/mL per 0.1 mg/kg/d, respectively; P = .001). The median C/D ratio was higher for TAC-treated patients with MDR-1-3435CC (14.1, 7.3, and 2.2 ng/mL per 0.1 mg/kg/d for CC, CT, and TT, respectively; P = .023). Neither CYP3A5 nor MDR-1-C3435T variants had an impact on CSA C/D ratios. Thus, CYP3A5 SNP has a significant impact on TAC dosing in Asian renal transplant recipients, which was likely to facilitate TAC metabolism. Although MDR-1-3435CC with higher P-gp expression should experience more TAC efflux and, therefore, lower TAC C/D ratios, all MDR-1-3435CC carriers were CYP3A5 nonexpressors; the latter ultimately contributed to the observed higher TAC C/D ratios in this population. This study advocates starting with a higher TAC dose for CYP3A5 expressors. Coadministration of DTZ may further optimize the TAC level through preferential P-gp binding and CYP3A4 inhibition.

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.

Conversion From Mycophenolate Mofetil to Enteric-Coated Mycophenolate Sodium in Stable Maintenance Renal Transplant Patients: Pooled Results From Three International, Multicenter Studies

BACKGROUND

Mycophenolate mofetil (MMF) is effective in renal transplant patients but concerns remain over its gastrointestinal (GI) tolerability. Enteric-coated mycophenolate sodium (EC-MPS; myfortic) has been developed with the intention of improving mycophenolic acid-related GI tolerability.

METHODS

Data were pooled in a planned analysis of three subprotocols of the myfortic Prospective Multicenter Study (myPROMS). In a 6-month study, efficacy and safety of converting stable renal transplant recipients from MMF to a bioequivalent dose of EC-MPS for mycophenolic acid exposure were evaluated. Treatment efficacy was recorded and graft function was assessed by measuring serum creatinine and estimating creatinine clearance. Adverse events (AEs) and infections were monitored and the incidence of EC-MPS dose changes was recorded.

RESULTS

A total of 588 patients were recruited, 564 (96%) of whom completed the study. The rate of treatment failure (defined as biopsy-proven acute rejection, graft loss, or death) was 1.9%, with no episodes of graft loss and only one death reported during the study. Renal function remained stable throughout the trial. EC-MPS was well tolerated; the majority of AEs were mild or moderate in severity. Dose reductions or interruptions were required by 6.3% and 1.9% of patients, respectively. Gastrointestinal AEs occurred in 138 patients (23.5%). The rate of dose adjustment as a result of a GI AE was 2.2%.

CONCLUSIONS

Equimolar conversion from MMF to EC-MPS in maintenance renal transplant patients was safe and maintained efficacy.

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. Key words: Genomics, Glomerulonephritis, History, Therapy, Translational medicine

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.

Preventing renal transplant failure

INTRODUCTION

Allograft failure due to immunological or non-immunological causes or a combination and patient death after transplantation are the 2 major causes of renal transplant loss. This paper reviews the various causes of allograft failure and explores strategies for its prevention.

RESULTS

Immune mechanisms of renal allograft failure are those mediated by acute and chronic rejection and are initiated by human leukocyte antigen (HLA) disparity between donor and recipient and increased recipient immune responsiveness that results in pre-sensitisation against HLA antigens. Better HLA matching between donor and recipient in both live-donor and cadaveric renal transplant recipients and the use of more potent immunosuppressants has reduced the incidence of acute rejection and resulted in improved overall graft survivals in recent years. However, as the use of more potent immunosuppression increases the risk of infections and malignancy, tailoring therapy by administering more potent immunosuppression to those at higher immunological risk may result in a better balance between the risks and benefits of immunosuppressive therapies. Ischaemia of the donor kidney, calcineurin inhibitor (CNI), mediated nephrotoxicity, reduced renal mass, hypertension, hyperlipidaemia and infections contribute to allograft failure through non-immunological mechanisms. Indeed, any cause of renal injury that results in nephron loss, either immunological or non-immunological, leads to reduced renal mass and initiates further renal damage due to hyperfiltration. Optimising these factors and minimising CNI nephrotoxicity are critical in reducing chronic allograft failure.

CONCLUSIONS

Optimising each of these time-dependent and immunosuppressive drug-related factors would allow the maximization of renal allograft function and survival.

Spectrum of severe infections in an Asian renal transplant population

Infections in renal transplant recipients (RTX) account for 26% of hospitalization days annually and 40% of overall mortalities. A retrospective study of infections requiring hospitalization occurring among 725 Asian RTX in 2002 was performed.

RESULTS

Serious infections requiring at least one hospitalization occurred in 9.2% of RTX (n = 67). Multiple pathogens affected 28.4% of patients, resulting in 118 infectious episodes during 93 hospitalizations. Mean age of affected patients was 48 years and female to male ratio was 2:1. Forty-one (61.2%) had impaired renal function (serum creatinine >141 mumol/L). Mean duration of hospitalization per patient was 17 days and the in-patient mortality rate was 17.9% eighty-one (87%) hospitalizations were for late infections (>6 months posttransplant). Cyclosporine (CsA) with prednisolone with or without azathioprine was the immunosuppressant in 62.7% (n = 42) of RTX but proportionally, infections were more frequent among RTX on other more potent immunosuppressants (n = 21; 7.4% CsA-based vs. 19.3%, potent, P < .05). Bacterial, viral, fungal, and Pneumocystis carinii infections comprised 64.4%, 20.3%, 5.9%, and 4.2% respectively. Urinary tract infection, pneumonia, and bacterial septicemia (35.52%, 31.6%, and 11.8%, respectively) were the major presentations. E. coli, cytomegalovirus (CMV), and Candida were the most common pathogens. Notably, 13 out of 18 (72.2%) viral CMV infections were co- infections, occurring together with bacterial infections.

CONCLUSIONS

Late infections with the use of potent immunosuppressives and concurrent CMV reactivation are a major cause of morbidity. Longer antibacterial prophylaxis and closer monitoring for CMV infections may help reduce morbidity.

Immunosuppression use in renal transplantation from Asian transplant centers: A preliminary report from the Asian Transplant Registry

Since the first renal transplant (RTx) in 1956 in Asia in Japan, over 100,000 RTx have been performed in over 300 centers across the region. A survey was conducted to evaluate immunosuppression (IS) use among Asian RTx. Briefly, directors of RTx centers were surveyed regarding IS use for RTx performed at their centers in 2001 for (1) induction therapy, (2) maintenance IS therapy at hospital discharge, (3) antirejection treatment (REJ) to 1 year post-RTx, and (4) maintenance IS therapy to 1 year post-RTx. Categories and types of IS included in the survey were polyclonal antilymphocyte antibodies (PAB), OKT3, IL2 receptor antibodies (IL2RAb), corticosteroids (CS), cyclosporine (CyA), tacrolimus (Tac), azathioprine (Aza), mycophenolate mofetil (MMF), Mizoribine (Miz), Sirolimus (Sir), and other agents. Though only 17 RTx centers in Asia responded to the survey, a wide variation in IS use was demonstrated. In the 334 living and 85 cadavericRTx among whom actual usage was reported, induction therapy was used in only 18.4% of Asian RTx (14.1%, IL2RAb; 4.3%, PAB), in contrast to the 59.3% reported as using induction IS among RTx from the UNOS database in the same year. For maintenance therapy at hospital discharge, 87.1% of Asian RTx received CyA-based IS while only 12.4% received Tac-based therapy. This is in contrast to the 55.3% use of Tac for new RTx in the United States. Generic CyA has widespread use in Asia with over 29.9% on CyA using generic versus the Neoral formulation. Azathioprine is still the predominant antimetabolite in use in Asian RTx, with MMF being used in only 33.6% of patients, in contrast to its 77% usage in the United States. Usage of Tac and MMF for maintenance therapy was significantly higher among cadavericRTx (P < .005). Corticosteroids were used in 51.1% of REJ episodes while PAB or OKT3 were used in 31.9% and 17% of REJ episodes, respectively. As these results may be skewed due to participation of few centers in the survey, greater participation will ensure more accurate evaluation of immunosuppression use in Asia for de novo RTx.

Conversion from mycophenolate mofetil to azathioprine in high-risk renal allograft recipients on cyclosporine-based immunosuppression

OBJECTIVE

In a randomized control trial of mycophenolate mofetil (MMF) versus azathioprine (AZA) with cyclosporine and steroids, we demonstrated that MMF reduced acute rejection (AR) among renal allograft recipients (RTX) who were of low to moderate risk. However, 10% had AR when converted from MMF to AZA at 6 months, postrenal transplantation (RT). Two clinical markers, abnormal serum creatinine (SCr) and proteinuria at 6 months, post-RT, were associated with AR postconversion. The present study examined the safety of such conversion in selected high-risk RTX at 1 year of MMF therapy.

METHODS

Thirteen high-risk RTX receiving MMF for either high panel reactive antibody (n = 9) or following AR (n = 4), with normal SCr and no proteinuria at 1 year, were selected for conversion. The incidence of AR, adverse events, and renal parameters (SCr, creatinine clearance, proteinuria) at 6 months postconversion was evaluated. Eight high-risk RTX who did not meet these selection criteria were retrospectively reviewed and used as controls.

RESULTS

Renal parameters (SCr 123 +/- 26 vs 129 +/- 27 mumol/L; pre- vs postconversion) were not significantly different; no episodes of AR or proteinuria were documented. Azathioprine was discontinued in two patients due to leukopenia. In the control group, one patient had graft loss from chronic rejection, whereas one developed posttransplant lymphoproliferative disease necessitating MMF withdrawal.

CONCLUSION

These results suggest that selective conversion from MMF to AZA after 1 year is safe, even in high-risk RTX. Normal SCr and absence of proteinuria are good screening parameters to identify patients at low risk for AR following such conversion.

Improving cadaveric organ donation rates in kidney and liver transplantation in Asia

In the year 2001, cadaveric kidney and liver transplant rates (CadTx) in countries with well-established transplant programs such as the United States and Spain ranged from 51 to 61.9 and 18.7 to 31.3 per million population (pmp), respectively. However, overall kidney and liver transplant rates in Asia are significantly lower at 4.3 and 0.3 pmp, respectively. Improving CadTx rates to meet the needs of organ failure patients poses several unique challenges in Asia. Across Asia, there is a wide disparity in prehospital emergency services and intensive care facilities that allow victims of cerebrovascular accident or trauma to be sent to hospitals for optimal management. Identification of the brain-dead victim in an intensive care setting, donor referral to an organ procurement coordinator/network, making the request for organ donation, and obtaining consent for organ donation from the family are other critical issues that impact on successful cadaveric donation. While affirmative legislation regarding organ donation is existent in most Asian countries, religious, ethnic, and cultural influences on concepts of death and the sanctity of the human body remain major barriers to obtaining consent for cadaveric donation. Although there are no overt objections to CadTx among the major religions of Asia, perceptions to the contrary largely limit consent for organ donation from potential donor families. Development of transportation and communication networks, public and donor hospital education programs, legislative initiatives such as presumed consent, and establishment of effective organ procurement practices are all key initiatives that will improve CadTx rates. Broadening donor criteria as with the use of expanded criteria donors, including non-heart-beating and older donors, may further improve cadaveric donation rates by as much as 20%. Finally, ethical transplant practices that prohibit trade in organs will promote an environment conducive to cadaveric donation. Together with efforts to increase living donor TX transplant rates, it is hoped that these measures will increase the supply of organs so as to meet the needs of organ failure patients in Asia.

Hand-assisted laparoscopic living donor nephrectomy

INTRODUCTION

Laparoscopic living donor nephrectomy (LDN) for renal transplantation is increasingly being performed to improve donor outcomes, by reducing perioperative morbidity without adversely impacting on allograft function in the recipient. We report our initial experience with hand-assisted LDN.

MATERIALS AND METHODS

From March 2002 to January 2003, 10 hand-assisted LDNs were performed in 2 institutions. Potential donors were evaluated for suitability, which included a renal angiogram. Only donors with uncomplicated vascular arrangements of the left kidney were offered this technique. During surgery, dissection of the donor kidney was performed laparoscopically, aided by the surgeon 's non-dominant hand inserted into the abdominal cavity through a hand-assist device via a 7-cm abdominal incision. The graft was subsequently delivered through the incision.

RESULTS

The mean operating time was 163.5 +/- 32 minutes and the mean warm ischaemic time was 2.16 +/- 0.72 minutes. There were no conversions to the open nephrectomy technique or requirement for perioperative transfusions. Postoperatively, patients returned to normal diet by 1.8 +/- 0.8 days and needed opiate analgesia up to a maximum of 48 hours. On average, the patients started ambulation at 2.1 +/- 0.9 days and were discharged 4 +/- 1.5 days after surgery. There were no significant complications other than 3 superficial wound infections. All grafts had immediate graft function. Serum creatinine levels of all recipients fell within 24 hours and reached baseline at a mean of 5.7 +/- 4.6 days.

CONCLUSIONS

Hand-assisted LDN is safe, feasible and can be performed with minimal morbidity. It also allows for excellent allograft function.

Pregnancy after renal transplantation: experience in Singapore General Hospital

INTRODUCTION

Renal transplantation offers the best hope for those women with end-stage renal disease who wish to have children. However, pregnancy after renal transplantation is associated with increased maternal and fetal morbidity. The aim of this retrospective study was to review the outcome of pregnancy in renal transplant patients in Singapore General Hospital.

MATERIALS AND METHODS

Forty-two pregnancies, occurring between December 1986 and December 2000, in 25 out of 141 renal transplant women in their reproductive age group (18 to 45 years old) were identified from our high-risk pregnancy record and retrospectively analysed.

RESULTS

Thirteen (31%) pregnancies were unsuccessful; 10 abortions, 2 ectopic pregnancies and 1 stillbirth. The remaining 29(69%) successful pregnancies were complicated by maternal anaemia (65.5%), superimposed hypertension (44.8%), premature rupture of membranes (27.6%), urinary (17.2%) and lower genital tract (13.8%) infections, abnormal glucose tolerance test (13.8%), premature delivery (44.8%), low-birth-weight babies (44.8%), small-for-gestational-age babies (20.7%) and intrauterine growth restriction (20.7%). There were no documented cases of multiple pregnancies, congenital anomalies or deterioration of renal function. The outcome of pregnancy was not statistically influenced by preconception renal function and transplant-conception interval.

CONCLUSIONS

Successful pregnancy is possible in women after renal transplantation. Such pregnancy is often associated with increased maternal and fetal complications and should be managed by a multidisciplinary approach in a tertiary centre. The function and survival of renal allograft was not adversely affected by pregnancy.

Case reports of low dose cyclosporine. A therapy in adult minimal change nephrotic syndrome

INTRODUCTION

Many centres still use steroids to induce remission in patients with minimal change nephrotic syndrome (MCNS) and failing that to give a course of cyclophosphamide, though some centres are already using cyclosporine A (CsA) as an alternative. We report the benefits of CsA therapy in 3 adults with difficult to treat MCNS in whom low dose CsA therapy proved to be efficacious.

CLINICAL PICTURE AND OUTCOME

The first patient had her 1st relapse after 8 years and thereafter had 2 more relapses, within 3 months of each other, in spite of therapy with cyclophosphamide. With CsA therapy, at a dose of 3.5 mg/kg body weight (BW)/day, she achieved lasting remission of 22 months as of September 1999 and is still in remission. The second patient had his relapses of nephrotic syndrome over a period of 10 years when treated with prednisolone and cyclophosphamide. On the 13th relapse, he achieved a remission lasting 21 months after a 3 month course of CsA at a dose of 4 mg/kg BW/day. With the 14th relapse, he took half the dose of CsA prescribed [only the morning dose of neoral CsA (2 mg/kg BW/day)] and still achieved a remission and has been in remission since. The third patient was a young woman, married for 2 years without children. She could not tolerate prednisolone because of erosive gastritis and she responded to a pulse dose of intravenous cyclophosphamide for her 1st episode of nephrotic syndrome with complete remission. However, when she relapsed 5 months later she did not respond to a similar dose of i.v. cyclophosphamide and was therefore treated with CsA (4 mg/kg BW/day) which induced a prompt remission 1 month after commencement of therapy and she is still in remission. The trough CsA levels for the 3 patients (range 41 to 107 ng/mL) and the calculated average CsA levels were lower than that used for post renal transplant immunosuppression. The trough CsA levels were, however, similar to that used in patients with MCNS from other series, though achieved at lower CsA doses.

CONCLUSION

Our study shows that low dose CsA is a useful agent for induction of remission of MCNS and maintenance of lasting remission. A low dose CsA regimen will make CsA more affordable.