Endemic nephropathy: A disease that requires further research

Abstract

Endemic nephropathy (EN) is a chronic, tubulointerstitial disease, described 60 years ago in the localized regions of the South-East Europe. In spite of numerous studies, the disease still attracts attention of researchers due to a great number of unanswered questions. This study is dedicated to some of those questions. Extensive field research, conducted in all endemic regions, showed the different disease prevalence rates, ranging from 0.3% to 10%. At the beginning of this century, the controversial opinions concerning the disease prevalence occurred, from the assumption that the disease disappears, to the data that the incidence does not change significantly. These differences occur due to a small number of studies conducted over the past thirty years and due to mass migrations from the endemic villages. That is the reason for the lack of exact data on EN prevalence in the endemic regions and for the lack of data on emigrants from endemic regions suffering from EN. EN is a family disease occurring only in the particular foci, thus it is considered that genetic factors, as well as environmental factors, are included in the occurrence of the disease. Currently, there are three hypotheses of EN etiology. One of the oldest assumptions about EN etiology is the one of ochratoxin A, a widely spread mycotoxin. Most of the attention is paid to aristolochic acid as an EN cause, but it is not excluded that, polycyclic aromatic hydrocarbons and other toxic compounds originating from lignite are causes of EN. Thus far, studies have not found out any biomarker which possesses enough specificity and sensitivity to discover and diagnose EN. Therefore, criteria have been defined, consisting of epidemiological, clinical and laboratory parameters which have enabled diagnosis of EN. Over the past decades, various research teams used different diagnostic criteria, thus aggravating results comparison. As a result, a group of experts have recently made a recommendation for screening, diagnosis, classifications and treatment of EN. However, since there is no pathognomonic biomarker for EN, the diagnosis of the disease is established on the basis of proving the presence of defined criteria and excluding other kidney diseases. It indicates that a search for the specific biomarker should be continued. Even after 60 years of endemic nephropathy studies, there are still unanswered questions which require further research by applying contemporary methods.