Consensus statement on screening, diagnosis, classification and treatment of endemic (Balkan) nephropathy.

Currently used diagnostic criteria in different endemic (Balkan) nephropathy (EN) centers involve different combinations of parameters, various cut-off values and many of them are not in agreement with proposed international guidelines. Leaders of EN centers began to address these problems at scientific meetings, and this paper is the outgrowth of those discussions. The main aim is to provide recommendations for clinical work on current knowledge and expertise. This document is developed for use by general physicians, nephrologists, urologist, public health experts and epidemiologist, and it is hoped that it will be adopted by responsible institutions in countries harboring EN. National medical providers should cover costs of screening and diagnostic procedures and treatment of EN patients with or without upper urothelial cancers.

TP53 Mutational signature for aristolochic acid: an environmental carcinogen.

This study was designed to establish the TP53 mutational spectrum of aristolochic acid (AA), examined in the context of endemic (Balkan) nephropathy, an environmental disease associated with transitional cell (urothelial) carcinomas of the upper urinary tract (UUC). Tumor tissue was obtained from residents of regions in Bosnia, Croatia and Serbia where endemic nephropathy has been prevalent for over 50 years. Fifty-nine TP53 mutations were detected in 42 of the 97 tumors analyzed. Mutational spectra were dominated by A:T to T:A transversions with the mutated adenines located almost exclusively on the nontranscribed strand. This marked strand bias is attributed to selective processing of aristolactam-dA adducts by transcription-coupled nucleotide excision repair. Hotspots for A:T to T:A mutations include codons 131 and 179 and the 5'-AG acceptor splice site of intron 6. The unique TP53 mutational signature for AA identified in this study can be used to explore the hypothesis that botanical products containing this human carcinogen and nephrotoxin are responsible, in part, for the high prevalence of UUC and chronic renal disease in countries where Aristolochia herbal remedies traditionally have been used for medicinal purposes.

Aristolochic acid and the etiology of endemic (Balkan) nephropathy.

Endemic (Balkan) nephropathy (EN), a devastating renal disease affecting men and women living in rural areas of Bosnia, Bulgaria, Croatia, Romania, and Serbia, is characterized by its insidious onset, invariable progression to chronic renal failure and a strong association with transitional cell (urothelial) carcinoma of the upper urinary tract. Significant epidemiologic features of EN include its focal occurrence in certain villages and a familial, but not inherited, pattern of disease. Our experiments test the hypothesis that chronic dietary poisoning by aristolochic acid is responsible for EN and its associated urothelial cancer. Using (32)P-postlabeling/PAGE and authentic standards, we identified dA-aristolactam (AL) and dG-AL DNA adducts in the renal cortex of patients with EN but not in patients with other chronic renal diseases. In addition, urothelial cancer tissue was obtained from residents of endemic villages with upper urinary tract malignancies. The AmpliChip p53 microarray was then used to sequence exons 2-11 of the p53 gene where we identified 19 base substitutions. Mutations at A:T pairs accounted for 89% of all p53 mutations, with 78% of these being A:T --> T:A transversions. Our experimental results, namely, that (i) DNA adducts derived from aristolochic acid (AA) are present in renal tissues of patients with documented EN, (ii) these adducts can be detected in transitional cell cancers, and (iii) A:T --> T:A transversions dominate the p53 mutational spectrum in the upper urinary tract malignancies found in this population lead to the conclusion that dietary exposure to AA is a significant risk factor for EN and its attendant transitional cell cancer.