Gitelman syndrome and glomerular proteinuria: a link between loss of sodium-chloride cotransporter and podocyte dysfunction?

We report on a 27-year-old patient presenting with chronic hypokalaemia, inappropriate kaliuresis, hypomagnesaemia and alkalosis, associated with moderate proteinuria. Genetic analysis evidenced a homozygous mutation (p.Arg399Cys) in the SLC12A3 gene coding for the sodium-chloride cotransporter (NCC), confirming the diagnosis of Gitelman syndrome. Further genetic testing did not show any mutation in NPHS2. A renal biopsy was performed in view of the unusual association with proteinuria. Light microscopy showed hypertrophy of the juxtaglomerular apparatus and discrete mesangial thickening. In addition to possible focal segmental glomerular sclerosis lesions, electron microscopy showed extensive segments of variably thickened glomerular basement membrane (GBM), contrasting with segments of regular GBM of low range thickness, and effacement of podocyte foot processes. Of interest, alterations of the GBM were also observed in a Slc12a3 knock-out mouse model for Gitelman syndrome. These data suggest that the association between Gitelman syndrome and secondary changes of the GBM is probably not coincidental. Possible mechanisms include angiotensin II- or renin-induced podocyte lesions, as well as chronic hypokalaemi

Unambiguous Detection of Multiple TP53 Gene Mutations in AAN-Associated Urothelial Cancer in Belgium Using Laser Capture Microdissection

In the Balkan and Taiwan, the relationship between exposure to aristolochic acid and risk of urothelial neoplasms was inferred from the A>T genetic hallmark in TP53 gene from malignant cells. This study aimed to characterize the TP53 mutational spectrum in urothelial cancers consecutive to Aristolochic Acid Nephropathy in Belgium. Serial frozen tumor sections from female patients (n = 5) exposed to aristolochic acid during weight-loss regimen were alternatively used either for p53 immunostaining or laser microdissection. Tissue areas with at least 60% p53-positive nuclei were selected for microdissecting sections according to p53-positive matching areas. All areas appeared to be carcinoma in situ. After DNA extraction, mutations in the TP53 hot spot region (exons 5-8) were identified using nested-PCR and sequencing. False-negative controls consisted in microdissecting fresh-frozen tumor tissues both from a patient with a Li-Fraumeni syndrome who carried a p53 constitutional mutation, and from KRas mutated adenocarcinomas. To rule out false-positive results potentially generated by microdissection and nested-PCR, a phenacetin-associated urothelial carcinoma and normal fresh ureteral tissues (n = 4) were processed with high laser power. No unexpected results being identified, molecular analysis was pursued on malignant tissues, showing at least one mutation in all (six different mutations in two) patients, with 13/16 exonic (nonsense, 2; missense, 11) and 3/16 intronic (one splice site) mutations. They were distributed as transitions (n = 7) or transversions (n = 9), with an equal prevalence of A>T and G>T (3/16 each). While current results are in line with A>T prevalence previously reported in Balkan and Taiwan studies, they also demonstrate that multiple mutations in the TP53 hot spot region and a high frequency of G>T transversion appear as a complementary signature reflecting the toxicity of a cumulative dose of aristolochic acid ingested over a short period of time

Prognostic relevance of number and bilaterality of positive surgical margins after radical prostatectomy

Item does not contain fulltextPURPOSE: Positive surgical margin (PSM) status following radical prostatectomy (RP) is a well-established prognostic factor. The aim of the present study is to evaluate whether number of PSMs or bilaterality of PSMs might have prognostic significance for biochemical recurrence (BCR) in the population with a PSM status following RP. METHODS: We evaluated 1,395 RP pathology reports from our center between 1980 and 2006. All patients who underwent (neo)-adjuvant therapy were excluded, leaving a cohort of 1,009 patients, with 249 (24.7%) subjects having a PSM at RP of whom 29.4% had multiple PSMs (>/= 2 sites), while 13.6% had bilateral PSMs. Median follow-up was 40 months (range 0-258 months). We used BCR-free survival as the primary study outcome. BCR was defined as any rise in PSA above or equal to 0.2 ng/ml. RESULTS: Of patients with a PSM status, 41% (95% CI: 33-49%) developed BCR within 5 years, compared to 12% (95% CI: 9-15%) in the population without a PSM. Multivariable analysis identified PSA at diagnosis and RP Gleason score as independent predictive factors for BCR. Increasing number and/or bilaterality of PSM did not lead to significant higher rates of BCR. CONCLUSION: In patients with a PSM, the number of positive sites or bilaterality of PSM status does not add prognostic information for risk of BCR. Survival curve slopes were different for patients with bilateral PSM, showing a significant tendency to progress to BCR earlier during follow-up than patients with unilateral PSM.1 februari 201

Chinese herbs nephropathy : pathology and etiology

Chinese herbs nephropathy (CHN) is a rapidly progressive interstitial nephropathy reported in young women who had followed a particular slimming regimen (Vanharwaghem et al., Lancet, 1993). It is characterized by early, severe anemia, mild tubular proteinuria, and normal arterial blood pressure (Kabanda et al., Kidney Int, 1995 ; Reginster et al., Nephrol Dial Transplant, 1997). The analysis of end-stage kidneys and upper urinary tract specimens removed at the time of renal transplantation (TP) in three patients with CHN allowed us to integrate the findings of renal interstitial fibrosis reported in early biopsies (Vanherweghem et al., Lancet, 1993) into a pathognomonic morphologic picture: an extensive, markedly a- or hypo-cellular interstitial fibrosis associated with tubular atrophy and global sclerosis of glomeruli with a decreasing cortico-medullar gradient (Cosyns et al., Kidney Int, 1994). We were puzzled by the presence of extensive urothelial atypia in the upper urinary tract of these patients warranting a careful follow-up to detect urinary tract malignancies. True bladder malignancies were subsequently identified (Cosyns et al, Lancet, 1994) and led our team to perform bilateral nephro-ureterectomies in all patient with CHN at the time of TP or shortly thereafter. We demonstrated a 40% prevalence of in situ urothelial carcinoma in 19 specimens removed from 10 such patients (Cosyns et al., Am J Kidney Dis, 1999), a finding subsequently confirmed by others (Nortier et la., New Engl J Med, 2000). Aristolochic acid (AA), a nephrotoxic and carcinogenic substance extracted from the Aristolochia species was identified in some herbs used to prepare the slimming pills (Van Haelen et al., Lancet, 1994) and suspected to be the cause of CHN. With the help of the Heidelberg group, we demonstrated the presence of pre-mutagenic AA-DNA adducts in the kidney tissue of CHN patients. We thus concluded that AA had indeed been ingested (Schmeiser at el., Cancer Res, 1996; Bieler et al., Carcinogenesis, 1997) and provided a pathophysiologic clue as to the CHN-associated malignancy. Our finding of immunohistochemical overexpression of p53, a tumor suppressive gene, in the neoplastic cells, further suggests that p53 is mutated in these cancers (Cosyns et al., Am J Kidney Dis, 1999). Moreover, induction of several salient pathologic and biologic features of CHN together with the development of urinary tract tumours in rabbits chronically administred AA as a single drug contained in the slimming pills (Cosyns et al, submitted). In contrast, the absence of renal interstitial fibrosis in rats after chronic AA exposure highlights species related diffenreces in the susceptibility to the toxicity of AA (Cosyns et al., Arch Toxicol, 1998). Finally, the similarities between CHN patients and those suffering from the Balkan endemic nephropathy (BEN) suggest that both conditions represent a single entity due ti AA (Cosyns et al., Kidney Int, 1994).Thèse de doctorat en sciences biomédicales (anatomie pathologique) -- UCL, 200

Aristolochic acid and 'Chinese herbs nephropathy': a review of the evidence to date.

Chinese herbs nephropathy (CHN) is a rapidly progressive interstitial nephropathy reported after the introduction of Chinese herbs in a slimming regimen followed by young Belgian women. It is characterised by early, severe anaemia, mild tubular proteinuria and initially normal arterial blood pressure in half of the patients. Renal histology shows unusual extensive, virtually hypocellular cortical interstitial fibrosis associated with tubular atrophy and global sclerosis of glomeruli decreasing from the outer to the inner cortex. Urothelial malignancy of the upper urinary tract develops subsequently in almost half of the patients. Suspicion that the disease was due to the recent introduction of Chinese herbs in the slimming regimen was reinforced by identification in the slimming pills of the nephrotoxic and carcinogenic aristolochic acid (AA) extracted from species of Aristolochia. This hypothesis was substantiated by the identification of premutagenic AA-DNA adducts in the kidney and ureteric tissues of CHN patients. Finally, induction of the clinical features (interstitial fibrosis and upper urothelial malignancy) typical of CHN in rodents given AA alone removed any doubt on the causal role of this phytotoxin in CHN, now better called aristolochic acid nephropathy (AAN). AAN is not restricted to the Belgian cases. Similar cases have been observed throughout the world, but AA is sometimes incriminated on the basis of the known content of AA in the herbs. The possibility remains that in some individuals in whom AA has not been demonstrated, other phytotoxins might be implicated. Biological and morphological features of AAN are strikingly similar to those reported in another fibrosing interstitial nephropathy of still unknown aetiology, Balkan endemic nephropathy (BEN). Interestingly, AA was incriminated as the cause of BEN many years ago, a hypothesis yet to be fully explored. The intake of AA and the presence of tissular AA-DNA adducts in patients with an unequivocal diagnosis of BEN remains to be demonstrated. The tragic phenomenon of CHN, recognised only 10 years ago, has been at the root of significant research and progress both in nephrology and oncology. It has provided a fascinating opportunity to understand the link between a fibrosing interstitial nephropathy and urothelial carcinoma. It allows the categorisation of interstitial nephritis on the basis of histological findings, of initiating toxic substances and of associated clinical features. Finally, it has led to the withdrawal in several countries of a previously unsuspected carcinogenic and nephrotoxic substance