Late onset of bladder urothelial carcinoma after kidney transplantation for end-stage aristolochic acid nephropathy: a case series with 15-year follow-up

BACKGROUND

Aristolochic acids are nephrotoxins and predispose to upper-tract urothelial carcinoma. The risk of bladder urothelial carcinoma after kidney transplantation and its relationship to upper-tract urothelial carcinoma is not well defined.

STUDY DESIGN

Case series.

SETTING & PARTICIPANTS

Single-center cohort of 38 women given kidney transplants for end-stage aristolochic acid nephropathy.

OUTCOMES & MEASUREMENTS

The prevalence of upper urinary tract urothelial carcinoma was determined by collecting pathological results of specimens obtained by means of bilateral ureteronephrectomy. We also established the cumulative incidence of bladder urothelial carcinoma in biopsies performed during prospective screening cystoscopies during a 15-year follow-up.

RESULTS

Upper-tract urothelial carcinoma was found in 17 patients with aristolochic acid nephropathy (44.7%). During follow-up, bladder urothelial carcinoma was diagnosed in 15 patients 68 to 169 months after cessation of aristolochic acid exposure (39.5%): 8 urothelial carcinoma in situ, 4 noninvasive low-grade papillary urothelial carcinoma, and 3 infiltrating urothelial carcinoma. 12 of 17 patients (71%) with a history of upper-tract urothelial carcinoma developed bladder urothelial carcinoma during follow-up, whereas this occurred in only 3 of 21 patients (14%) without upper-tract urothelial carcinoma (P < 0.01). Despite local and/or systemic chemotherapy, 3 patients died and 2 radical cystectomies were performed.

LIMITATIONS

Small sample size of this case series.

CONCLUSIONS

Upper-tract and bladder urothelial carcinoma are dramatic complications in kidney transplant recipients with aristolochic acid nephropathy, confirming the carcinogenic properties of aristolochic acids. We identified upper-tract urothelial carcinoma as a potent risk factor for the subsequent development of bladder urothelial carcinoma after kidney transplantation for aristolochic acid nephropathy. Because this complication may occur years after aristolochic acid discontinuation, we suggest regular cystoscopies in addition to the bilateral ureteronephrectomy in kidney transplant recipients with aristolochic acid nephropathy.

[World kidney Day 2008: the impact of epidemiology of kidney diseases in Belgium]

The World Kidney Day offers a crucial opportunity to the Belgian associations of nephrologists to inform public and medical communities about the global problem of chronic kidney disease (CKD). According to epidemiological data from GNFB/ NBVN registries in our country, cardiovascular diseases and diabetes 2 are responsible for an increasing amount of CKD cases with pejorative evolution to end-stage renal disease requiring cost-effective renal replacement therapies (haemodialysis, peritoneal dialysis or renal transplantation). In these patients, the high level of comorbidities and the late referral to the nephrologists are recognized as enhanced morbidity and mortality factors. These facts underline the need for the nephrologists to stimulate collaboration with general practitioners and specialists from other disciplines in order to set up systematic screening procedures and early follow-up of patients at risk of developing CKD. These procedures should contribute to reduce the progression rate of renal function impairment.

[Experimental nephrology unit: overview and research projects]

After a short historical background of the Laboratory, the main research topics--renal toxicology, physiopathology of renal interstitial fibrosis and hormonology--are described in the perspective of a partnership between research clinicians and full time scientists. National as well as international scientific collaborations underline the need of combining expertises, stimulating also the training of youngest colleagues to the experimental approach of their future discipline.

[Nephropathy caused by Chinese plants and aristolochic acids: from clinical observation to experimental model]

In 1992, a new type of progressive renal fibrosis was reported in patients after the intake of weight-reducing pills containing a Chinese herb (Aristolochia fangchi) rich of nephrotoxic and carcinogenic aristolochic acids (AA). Up to now, Chinese herb nephropathy (CHN), also called aristolochic acid nephropathy (AAN), has been observed in more than 100 patients in Belgium, but also in numerous patients all around the world. The main histological characteristics of CHN are tubular atrophy and interstitial fibrosis leading to severe renal functional impairment and end-stage renal failure. Urothelial carcinomas were also found in about 50% CHN patients suffering from end-stage renal failure. Experimentally, the main features of CHN were successfully reproduced after 35 days of daily AA injections to rats. Starting from this model, we demonstrated that other potential nephrotoxic substances (dexfenfluramine, diuretics) also contained in the weight-reducing pills, did not enhance the renal toxicity of AA. Interestingly, the inhibition of renin angiotensin system did not prevent the development of renal lesions, suggesting that, in contrast with other animal models, physiopathological mechanisms leading to renal fibrosis might be largely independent of angiotensin II. From clinical observations to experimental studies, we currently increased our knowledge in the understanding of pathophysiological mechanisms of nephropathies of toxic origin. Botanicals which are known or suspected to contain AA are still sold on Web sites or over-the-counter markets. It is not surprising then to find new AAN cases reported in the medical literature. Therefore, further studies are needed to elucidate pathways of AA-related nephrotoxicity and carcinogenicity in order to develop therapeutic strategies.

Sclerosing peritonitis: report of three cases

Sclerosing peritonitis is a dramatic complication of continuous ambulatory peritoneal dialysis and chronic peritoneal inflammation. Both visceral and parietal surfaces of the peritoneal cavity are involved. A thickened peritoneum encloses the small intestine in a "cocoon" formation which often leads to intestinal occlusion. CT scan may help obtaining an early diagnosis but diagnosis is often established with some delay or even at the time of laparotomy. Our report describes three cases of this uncommon peritoneal fibrosis syndrome which caused intestinal obstruction requiring surgical intervention.

[The medico-surgical department of nephrology dialysis and renal transplantation]

The Department of Nephrology of the Hospital Erasme, opened 25 years ago, is now performing, each year, 22,000 hemodialysis sessions, 800 patient-weeks of peritoneal dialysis treatment and 70 renal grafts. Scientific contributions of the department deal with vascular access for hemodialysis, susceptibility to infections of dialyzed patients, parathyroid surgery, biocompatibility of dialysis membranes, predictive factors of renal graft survival, immunosuppression with monoclonal antibodies, experimental studies of graft tolerance and rejection, toxic nephropathies. The most original contributions are related to anaphylactoïd reactions in hemodialysis by association of acrylonitrile membranes with inhibition of the converting enzyme, to advantages and side effects of OKT3 monoclonal antibody and to discovery and study of the Chinese herbs nephropathy.

High prevalence of fenfluramine-related aortic regurgitation in women with end-stage renal disease secondary to Chinese herb nephropathy

BACKGROUND

Non-controlled studies have noted a high prevalence of valvular regurgitation in patients with Chinese herb nephropathy; most of these patients had taken appetite suppressants. We aimed to determine the prevalence of valvular regurgitation and the role of appetite suppressants in patients with Chinese herb nephropathy.

METHODS

This case-controlled echocardiographic study included 40 patients with end-stage renal failure due to Chinese herb nephropathy and 37 age-matched controls with end-stage renal disease due to nephropathy of other origin. Quantification of cumulative doses of appetite suppressants was performed.

RESULTS

Aortic regurgitation was detected in 52.5% of patients with Chinese herb nephropathy, 72+/-1 months after stopping appetite suppressants, and in 21.6% of controls (P=0.009). No difference was found in the incidence of mitral or tricuspid regurgitation. A history of slimming medication was the only significant determinant for aortic regurgitation (P=0.009). Higher cumulative doses of Chinese herbs, (dex)fenfluramine and diethylpropion were observed in patients with Chinese herb nephropathy with, when compared to those without, aortic regurgitation. The dose-response relationship between the cumulative dose of drugs and the presence of aortic regurgitation was significant for fenfluramine only (chi-square=5.16, P=0.024).

CONCLUSIONS

Six years after stopping appetite suppressants, aortic regurgitation remains highly prevalent among patients with end-stage Chinese herb nephropathy. The dose-related association with fenfluramine intake strongly confirms a determinant pathogenic role of anorectic drugs.

Effects of dexfenfluramine on aristolochic acid nephrotoxicity in a rat model for Chinese-herb nephropathy

Chinese-herb nephropathy (CHN) is a progressive renal interstitial fibrosis initially reported after concomitant intake of an anorexigen, (dex)fenfluramine, and a Chinese herb ( Aristolochia fangchi) containing nephrotoxic and carcinogenic aristolochic acid (AA). We thus tested the possible enhancing effect of the active enantiomer dexfenfluramine (DXF) on AA nephrotoxicity in a rat model for CHN. Groups of 12 salt-depleted male Wistar rats received daily subcutaneous injections of 7 mg/kg body weight DXF (DXF group), 7 mg/kg body weight AA (AA group), a combination of the same doses of AA and DXF (AA+DXF group), or vehicle (control group) for up to 35 days. Six animals per group were killed on day 10 and the remaining six on day 35. Renal function was evaluated by determining serum creatinine and urinary leucine aminopeptidase activity. Histological evaluation of kidney samples was performed and tubulointerstitial injuries were semiquantified. The DXF group did not differ from controls for any parameter. Similarly elevated serum creatinine levels, decreased leucine aminopeptidase enzymuria, and renal lesions were observed in the AA and the AA+DXF groups after both 10 and 35 days. The formation of specific AA-DNA adducts in liver and renal tissue samples was assessed by the (32)P-postlabelling method. Specific AA-DNA adduct levels were significantly increased in kidney tissues from AA+DXF rats compared with AA rats. These functional and histological data suggest that DXF does not enhance AA nephrotoxicity in a rat model for CHN. Further investigations are needed to clarify the mechanism by which DXF may enhance AA-DNA adduct formation.

Progression rate of Chinese herb nephropathy: impact of Aristolochia fangchi ingested dose

BACKGROUND

Renal failure after ingestion of Chinese herbs between 1990 and 1992 was related to the replacement of Stephania tetrandra by Aristolochia fangchi (ST-AF), containing nephrotoxic and carcinogenic aristolochic acids. However, the relationship between ST-AF and renal failure is still a matter of debate. We therefore tested the impact of the ST-AF ingested dose on the progression of renal function deterioration.

METHODS

Analysis of medical charts and prescriptions between 1990 and 1992 was carried out to determine the presence of risk factors for kidney failure and the cumulative dose of pill components. Individual progression rate of renal impairment was studied by the time-course of the inverse of blood creatinine level (1/P(creat)).

RESULTS

Patients were divided into an end-stage renal disease (ESRD) group (n=44) and a chronic renal failure (CRF) group (n=27) according to their P(creat) at the time of this study. The mean number of risk factors (+/-SD) was equally distributed within both groups (1.50+/-0.18 vs 1.59+/-0.17, P=0.74). Patients from the ESRD group ingested significantly higher cumulative doses of ST--AF (192+/-13.1 g vs 138+/- 16.3 g), Magnolia officinalis, (80.1+/-6.3 g vs 59.8+/-11.7 g), diethylpropion (14.7+/-1.4 g vs 10.0+/-1.4 g) and fenfluramine (14.1+/-1.6 g vs 8.7+/-1.3 g). In the ESRD group, some patients who had received steroids had a slower progression to ESRD than the others. In multiple regression analysis, ST-AF emerged as the only significant drug predicting the slope of the progression of renal failure. Moreover, hypothesizing a linear dose-response relationship, the risk of developing ESRD linearly increased with ST-AF doses.

CONCLUSIONS

The relationship between the cumulative ST-AF dose and the renal failure progression rate confirms that regular ingestion of Aristolochia sp. extracts is causally involved in the onset of chronic interstitial nephropathy leading to ESRD.

Recurrent "Flexispira rappini" bacteremia in an adult patient undergoing hemodialysis: case report

A blood culture from a 65-year-old febrile man undergoing hemodialysis revealed, 5 days after inoculation, an unusual gram-negative fusiform rod with darting motility. During another episode of fever 21 days later, this Campylobacter-like organism was again recovered from three blood cultures and subcultured under an H2-enriched microaerobic atmosphere. The organism was catalase negative and oxidase positive and hydrolyzed urea rapidly. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of whole-cell proteins was indistinguishable from that of "Flexispira rappini" LMG 8738 described by Archer et al. in 1988 (J. R. Archer, S. Romero, A. E. Ritchier, M. E. Hamacher, B. M. Steiner, J. H. Bryner, and R. F. Schell, J. Clin. Microbiol. 26:101-105, 1988). The analysis of the 16S ribosomal DNA sequence revealed a similarity of 99.3% between the two strains. The patient recovered completely after a 4-week course of meropenem therapy. This is the first reported case of a recurrent "F. rappini" bacteremia in an adult patient, which confirms that this organism may be an invasive pathogen in immunocompromised patients, like other newly described Helicobacter species.

Assessment of bone response to systemic therapy in an EORTC trial: preliminary experience with the use of collagen cross-link excretion. European Organization for Research and Treatment of Cancer

This study was designed to evaluate new bone resorption and tumour markers as possible alternatives to serial plain radiographs for the assessment of response to treatment. Thirty-seven patients with newly diagnosed bone metastases from breast cancer, randomized to receive oral pamidronate or placebo tablets in addition to anticancer treatment within the context of a multicentre EORTC trial, who were both assessable for radiographic response in bone and had serum and urine samples collected for more than 1 month were studied. The markers of bone metabolism measured included urinary calcium (uCa), hydroxyproline (hyp), the N-telopeptide cross-links of type I collagen (NTx) and total alkaline phosphatase. The tumour markers measured were CA15-3 and cancer-associated serum antigen (CASA). Before treatment, levels of Ntx, uCa and Hyp were elevated in 41%, 24% and 28% respectively, and CA15-3 and CASA increased in 69% and 50%. For assessment of response and identification of progression, Ntx was the most useful bone marker. All markers behaved similarly in no change (NC) and partial response (PR) patients. There was a significant difference (P < or = 0.05) in Ntx levels (compared to baseline) at 1 and 4 months and in CA15-3/CASA at 4 months between patients with PR or NC and those with progressive disease (PD), and at 4 months between those with time to progression (TP) > 7 and those with TP < or = 7 months. The diagnostic efficiency (DE) for prediction of PD following a > 50% increase in Ntx or CA15-3 was 78% and 62% respectively. An algorithm to predict response to therapy has been developed for future prospective evaluation.

[Herbal remedies and nephrotoxicity]

Numerous substances from vegetal origin used as herbal remedies can be nephrotoxic. This article summarizes several circumstances of development of acute or chronic renal failure in which the responsible agent has been identified after a thorough toxicologic study. The Chinese herbs nephropathy is extensively described, detailing not only the epidemiological and histological aspects but also the extrarenal and neoplastic complications recently reported.

Initial high anti-emetic efficacy of granisetron with dexamethasone is not maintained over repeated cycles

We have reported previously that the anti-emetic efficacy of single agent 5HT3 antagonists is not maintained when analysed with the measurement of cumulative probabilities. Presently, the most effective anti-emetic regimen is a combination of a 5HT3 antagonist plus dexamethasone. We, therefore, assessed the sustainment of efficacy of such a combination in 125 patients, scheduled to receive cisplatin > or = 70 mg m(-2) either alone or in combination with other cytotoxic drugs. Anti-emetic therapy was initiated with 10 mg of dexamethasone and 3 mg of granisetron intravenously, before cisplatin. On days 1-6, patients received 8 mg of dexamethasone and 1 mg of granisetron twice daily by oral administration. Protection was assessed during all cycles and calculated based on cumulative probability analyses using the method of Kaplan-Meier and a model for transitional probabilities. Irrespective of the type of analysis used, the anti-emetic efficacy of granisetron/dexamethasone decreased over cycles. The initial complete acute emesis protection rate of 66% decreased to 30% according to the method of Kaplan-Meier and to 39% using the model for transitional probabilities. For delayed emesis, the initial complete protection rate of 52% decreased to 21% (Kaplan-Meier) and to 43% (transitional probabilities). In addition, we observed that protection failure in the delayed emesis period adversely influenced the acute emesis protection in the next cycle. We conclude that the anti-emetic efficacy of a 5HT3 antagonist plus dexamethasone is not maintained over multiple cycles of highly emetogenic chemotherapy, and that the acute emesis protection is adversely influenced by protection failure in the delayed emesis phase.

Cleavage of atrial natriuretic peptide by a kidney membrane-bound carboxypeptidase A

An enzymatic activity that cleaved the C-terminal Tyr of ANP (1-28) was characterized in human kidney microvillar membranes by using 125I-labeled rat ANP as substrate. This activity was inhibited by potato carboxypeptidase inhibitor (PCI) and 1.10 phenanthroline, suggesting that it corresponded to a metallo-carboxypeptidase. Solubilization experiments indicated that the carboxypeptidase activity could be recovered in the supernatant after 1% Triton X-100 extraction. As separation by ion exchange chromatography revealed several peaks of enzyme activity, PCI coupled to Sepharose was used for purification. This step resulted in a single protein band at 30 kDa, as analyzed by SDS-PAGE.

Enhancing endogenous effects of natriuretic peptides: inhibitors of neutral endopeptidase (EC.3.4.24.11) and phosphodiesterase

Because diuretic drugs remain the main treatment for disorders of sodium and water metabolism, the quest for improved diuretic and natriuretic agents continues in the hope of achieving fewer side effects and a more rational basis in pathophysiology. One aim has been to enhance endogenous diuretic and natriuretic activity by selective manipulation of atrial natriuretic peptide and related compounds. The first approach has been to inhibit degradation of these peptides using inhibitors of their main catabolic enzyme, neutral endopeptidase, and to offset any antagonistic effect of the renin-angiotensin system by combination with an angiotensin-converting enzyme inhibitor. The second and more recent approach has been to inhibit breakdown of the second messenger of atrial natriuretic peptide, cGMP, using phosphodiesterase inhibitors. As yet, neutral endopeptidase inhibition has not advanced successfully beyond animal experimentation and phosphodiesterase inhibition is still in its infancy. Both strategies suffer from the problem that, on the one hand, neutral endopeptidase metabolizes a variety of bioactive peptides, including endothelin, and it is not possible to develop inhibitors that will be selective for a given peptide; whereas, on the other hand, there are several phosphodiesterase isoforms metabolizing cGMP and cAMP, both second messengers for many different bioactive compounds, and selective inhibitors are still under development.

Urinary neutral endopeptidase in workers exposed to cadmium: interaction with cigarette smoking

OBJECTIVES

Structural impairment of the renal proximal tubular epithelium induced by cadmium (Cd) was investigated by measuring the concentration of neutral endopeptidase 24.11 (NEP), an ectoenzyme of the apical brush border, in the urine of 106 male workers employed in a Cd smelter (among whom 52 were occupationally exposed to Cd), and by comparing it with other tubular markers (low molecular weight proteins, lysosomal enzymes).

METHODS

NEP (EC 3.4.24.11), beta-N-acetyl-glucosaminidase (NAG) (EC 3.2.1.30), and NAG-B isoenzyme activities were measured by fluorimetric assays, whereas the concentrations of retinol binding protein (RBP), beta 2-microglobulin (beta 2M), and Clara cell protein (CC16) were measured by automated latex agglutination techniques.

RESULTS

An increased urinary excretion of NEP as well as microproteins was found only in subjects excreting more than 5 micrograms Cd/g creatinine. In this group, NEP concentrations were significantly higher in the subjects who smoked. This significant interaction could not be found for any other marker tested.

CONCLUSIONS

The data suggest that NEP enzymuria is high even at low exposures to Cd (with a threshold of urinary cadmium excretion (U-Cd) at 5 micrograms/g creatinine), indicating early structural alterations. Moreover, its particular sensitivity to smoking could be useful in the detection of new population clusters potentially more susceptible to development of nephrotoxic insult.

Human neutrophil and plasma endopeptidase 24.11: quantification and respective roles in atrial natriuretic peptide hydrolysis

Neutral endopeptidase 24.11 activities were quantified on human peripheral blood cell preparations (reflecting the enzyme concentration on the surface of neutrophils) and in the corresponding diluted plasmas by a spectrofluorimetric assay. Despite statistically identical values in both compartments, enzymatic activity towards atrial natriuretic peptide was not comparable. Indeed, incubation of the radiolabelled peptide in whole blood resulted in the thiorphan-sensitive production of the labelled metabolites Phe-Arg-Tyr and the Cys-Phe bond-cleaved peptide. A similar degradation pattern was observed for blood cells but not for plasma, providing evidence for the exclusive involvement of neutrophil endopeptidase in this peptide inactivation. In search for plasma component(s) susceptible to inhibit enzymatic activity, we observed that in the presence of alpha 2-macroglobulin at the physiological concentration of 3.5 mg mL-1, endopeptidase activity decreased from 100% to 51.2 +/- 8.9% (P = 0.002). Our data suggest that this protein could play a role in the endogenous inhibition of plasma endopeptidase activity.

Atriopeptin III degradation by endopeptidase 24.11: the Cys-Phe bond is not the preferential cleavage site

Incubation of rANP(5-28)--also called atriopeptin III (AP III)--with purified endopeptidase 24.11 led preferentially to the production of Phe-Arg-Tyr, while other products of minor importance were detected. One of these was identified as rANP(5-25) (atriopeptin I) (AP I). This hydrolysis pattern of endopeptidase 24.11 towards AP III differs from the known favored site of cleavage at the Cys7-Phe8 bond of rANP(1-28). Moreover, by comparison with rANP(1-28), the degradation rate of AP III was slower. These data suggest that N-terminal peptide truncation results in conformational and/or charge modifications leading to a different positioning of the peptide in the endopeptidase 24.11 active site. In most hypothalamic nuclei of the rat brain known to contain AP III and endopeptidase 24.11, the preferential Ser25-Phe26 bond hydrolysis, although supposed to be responsible for a reduced degradation rate, might represent an effective enzymatic pathway of catabolism for AP III.

Enzymatic degradation of endothelin-1 by activated human polymorphonuclear neutrophils

Endothelin-1 (ET-1) is a potent vasoconstrictor peptide secreted by endothelial cells. We investigated whether polymorphonuclear neutrophils (PMN) were able to destroy this peptide by enzymatic hydrolysis produced either by the membrane-bound endopeptidase 24.11 or by lysosomal proteinases released in the medium by activated cells. Resting and activated PMN were incubated with 125I-labelled ET-1 and the degradation fragments were analyzed by HPLC. A marked degradation of ET-1 was observed only in the presence of the stimulated cells, leading to the generation of seven radiolabelled peaks. Addition of phosphoramidon had no effect on the appearance of these metabolites, while soybean trypsin inhibitor abolished almost completely the degradation of the peptide, suggesting a role of cathepsin G in ET-1 hydrolysis. Among the purified leukocyte enzymes tested, cathepsin G hydrolyzed 125I-labelled ET-1 at the higher rate and gave rise to two radiolabelled peaks already observed in the presence of activated PMN. Incubation of unlabelled ET-1 with purified cathepsin G allowed to identify a major cleavage site corresponding to the His16-Leu17 bond, leading to the formation of inactive [1-16] fragments and the C-terminal pentapeptide. This mechanism of ET-1 inactivation could play a role in acute inflammatory reaction where PMN adhere to the vascular endothelial cells.

Role of the captopril test in renovascular hypertension: a case report

This article reports the case of a rapidly severe stenosis of the right renal artery, causing uncontrolled hypertension. After failure of a percutaneous transluminal renal angioplasty, which provoked the thrombosis of the vessel, a surgical revascularization was performed after +/- eighteen hours of renal ischemia. Blood pressure, blood urea nitrogen and serum creatinine returned to normal values. A dramatic improvement of the right renal function was attested at the hippuran scintigraphy after a dose test of captopril. The results of renographic studies obtained in this clinical case underline the role of the captopril radionuclide test in detection and follow-up after treatment of renovascular hypertension.

Pathological release of urinary endopeptidase 24.11 early after renal transplantation

Endopeptidase 24.11 (EC 3.4.24.11) enzymatic activity was spectrofluorimetrically measured in human urine, using a synthetic peptidic substrate. Urinary endopeptidase 24.11 output (Uendo) was determined in 24-hour urine samples of 10 kidney transplant recipients during the first 2 weeks after surgery. In 9 patients, a large increase in Uendo levels was noted during the 1st and/or the 2nd postoperative days (mean +/- SEM of peak Uendo 624 +/- 122 micrograms/24 h, p = 0.0003 as compared to 239 +/- 20 micrograms/24 h in a healthy control population). This occurred whether patients received OKT3 (n = 6) or cyclosporine A (n = 3) as primary immunosuppression. Uendo returned to normal between the 3rd and the 5th postoperative day. We conclude that renal transplantation is associated with an early and marked release of endopeptidase 24.11 in urine. This could be due to the potentially toxic effects of ischemia and/or immunosuppressive drugs on the proximal tubular epithelium. The clinical usefulness of urinary endopeptidase 24.11 as a marker of tubular injury remains to be assessed.