Renal transplantation in patients with Balkan endemic nephropathy

Local and Systemic Oxidative Stress in Balkan Endemic Nephropathy Is Not Associated with Xanthine Oxidase Activity

Balkan endemic nephropathy (BEN) represents a chronic tubulointerstitial nephropathy which is followed by the progression of kidney fibrosis to end-stage kidney failure. The critical involvement of poisons in food (aristolochic acid (AA), ochratoxin, and heavy metals) and selenium deficiency are among nutritive factors which contribute to the pathogenesis of BEN, due to reactive oxygen species (ROS) liberation and/or decreased antioxidative defence system. The aim of the study is to distinguish a possible systemic and local origin of ROS through the measurement of xanthine oxidase (XO) activity in urine and plasma, along with the determination of the oxidative changes in lipids and proteins. The study included 50 patients with BEN and 38 control healthy subjects. We noted increased levels of both thiobarbituric acid-reactive substances (TBARS) and advanced oxidation protein products (AOPPs) in the plasma of patients with BEN, compared to the control group (p < 0.001). The urinary levels of AOPPs were higher in patients with BEN in comparison to the control (p < 0.001). The specific activity of XO was significantly lower in plasma and urine in BEN samples, compared to controls (p < 0.005). Based on these results, we hypothesize that XO might not be considered a direct systemic or local contributor to ROS production in BEN, most probably because of the diminished kidney functional tissue mass and/or AA-induced changes in purine nucleotide conformation. The increased AOPP and TBARS level in both plasma and urine in BEN may predict ROS systemic liberation with toxic local effects.

Urothelial carcinoma of an allograft ureter 10 years after deceased donor kidney transplantation

The incidence of urothelial carcinoma (UC; formerly transitional cell carcinoma) is higher among renal transplant recipients compared with the general population. Upper urinary tract UC (UUT-UC) of allograft urothelium is a rare event with approximately 40 cases reported in the literature. Herein, we describe the clinical presentation and management of UUT-UC in a transplant ureter 10 years after deceased donor kidney transplantation.

Characteristics of Upper Urothelial Carcinoma in an Area of Balkan Endemic Nephropathy in South Serbia. A fifty-year Retrospective Study

Aims and background

Upper urinary tract transitional cell carcinoma, a relatively rare tumor, is up to 100 times more frequent in regions with Balkan endemic nephropathy. Characteristics of transitional cell carcinoma in the endemic South Morava Region in Serbia in the previous 50 years were evaluated.

Patients

We analyzed 477 cases with pathologically confirmed transitional cell carcinoma who underwent surgery from 1957 to 2006: 91 from endemic, 106 from adjacent and 280 from control settlements. Cases in the study came from 10 endemic villages, 46 adjacent villages, 51 control villages and the city of Nis.

Results

The increase in number of transitional cell carcinoma from 1957 was followed by a peak between 1967 and 1978 (yearly incidence 21.9 per 100,000) and a slow decrease thereafter to 7.4 (1997–2006). In the control settlements, the increase was steady. Reduced kidney function at surgery was found in 58% of patients from endemic and in 20% from control settlements. Age at surgery has significantly increased from 52.3 and 51.5 (1957–1966) to 70.9 and 66.1 (1997–2006) for endemic and control settlements, respectively. The female sex was predominant in endemic and adjacent settlements and the male sex in control settlements. Transitional cell carcinoma from endemic settlements was of a lower grade in the period from 1957–1986, but in the period from 1987–2006 they were predominantly high grade. Low tumor stage (pTa-pT1) predominated in transitional cell carcinoma from the endemic and adjacent but not the control settlements in the period from 1957 to 1986. However, in the last 20 years, upper urinary tract transitional cell carcinoma stage increased, the highest in the period from 1997 to 2006 in all settlements studied. Conservative surgery was advocated for transitional cell carcinoma in Balkan endemic nephropathy areas up to 1996. Transitional cell carcinoma are now more malignant and more advanced than before, and a less aggressive approach is used only for absolute indications.

Conclusions

An increased number of transitional cell carcinoma in endemic settlements was observed, markedly decreasing in the last decade. An increasing age and a shorter survival were recorded in patients both from Balkan endemic nephropathy and control settlements. Sporadic cases upper urinary tract transitional cell carcinoma in settlements adjacent to endemic settlements were demonstrated. Free full text available at www.tumorionline.it

Balkan endemic nephropathy: an update on its aetiology

Balkan endemic nephropathy (BEN) is a unique, chronic renal disease frequently associated with upper urothelial cancer (UUC). It only affects residents of specific farming villages located along tributaries of the Danube River in Bosnia-Herzegovina, Croatia, Macedonia, Serbia, Bulgaria, and Romania where it is estimated that ~100,000 individuals are at risk of BEN, while ~25,000 have the disease. This review summarises current findings on the aetiology of BEN. Over the last 50 years, several hypotheses on the cause of BEN have been formulated, including mycotoxins, heavy metals, viruses, and trace-element insufficiencies. However, recent molecular epidemiological studies provide a strong case that chronic dietary exposure to aristolochic acid (AA) a principal component of Aristolochia clematitis which grows as a weed in the wheat fields of the endemic regions is the cause of BEN and associated UUC. One of the still enigmatic features of BEN that need to be resolved is why the prevalence of BEN is only 3-7 %. This suggests that individual genetic susceptibilities to AA exist in humans. In fact dietary ingestion of AA along with individual genetic susceptibility provides a scenario that plausibly can explain all the peculiarities of BEN such as geographical distribution and high risk of urothelial cancer. For the countries harbouring BEN implementing public health measures to avoid AA exposure is of the utmost importance because this seems to be the best way to eradicate this once mysterious disease to which the residents of BEN villages have been completely and utterly at mercy for so long.

Interplay between chronic kidney disease (CKD) and upper tract urothelial carcinomas (UUC): foe or friend?

Although upper tract urothelial carcinomas (UUC) is curable through nephrectomy or nephroureterectomy, progression of chronic kidney disease (CKD) and CKD-related mortality have been highlighted as clinical challenges in recent years owing to the loss of a large number of nephrons. While CKD can promote the development of UUC, other risk factors such as hypertension, diabetes mellitus, advanced age, and anemia can facilitate the progression of CKD. Conversely, CKD is especially prevalent in UUC patients. However, the relationship between CKD and UUC, mechanisms for CKD causing UUC, and gender disparity of UUC of CKD patients have so far not been well-reviewed. As UUC gradually grows, the cancer can be a physical obstacle in the urinary tract. It will cause an increased tract pressure, subsequently resulting in the dysfunction of both nephrons and kidney. At the molecular level, reduced level of oxidative stress was observed in female UUC patients. Furthermore, radical nephrectomy therapy for UUC patients accelerates the progress of chronic kidney dysfunction. Incidentally, the remedies for CKD containing aristolochic acid (AA) are carcinogenic. Our present review offers a comprehensive look at the relationship between CKD and UUC from multiple perspectives. Early and precise identification of progression of CKD and UUC will benefit the patients at high-risk of CKD or UUC, which will also be instructive in directing timely and effective therapeutic interventions whenever necessary. It may also shed light on unveiling the underlying mechanisms of carcinogenesis of UUC, preventing CKD progression, and prolonging the patients' overall survival.

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.

Upper urothelium carcinomas in Croatian endemic area

BACKGROUND/AIMS

Endemic nephropathy (EN) is a chronic tubulointerstitial disease. Strong association between EN and urothelial carcinoma was noted as early as 40-50 ago. The aim of the study was to determine and compare specific mortality and morbidity of renal pelvis and ureter (upper urothelium) carcinoma (UUC) among Croatia as a whole, Brod-Posavina County, and Croatian endemic area.

METHODS

Data on UUC mortality and morbidity were analyzed. Indirect standardization was employed on data comparison by calculating standardized mortality ratio and morbidity ratio.

RESULTS

Our study results showed the specific mortality rate in the endemic area to be 26.3-fold and 7.3-fold the rate recorded in Croatia and Brod-Posavina County, respectively. The mean standardized mortality ratio obtained by indirect standardization yielded an 8-fold and 32-fold risk of death from UUC in the endemic area vs. Brod-Posavina County and Croatia as a whole, respectively. These data revealed the specific morbidity in the Croatian endemic area and Brod-Posavina County to be 13.95-fold and 3.78-fold the morbidity recorded at the national level, respectively. The standardized morbidity ratio also showed the risk of developing UUC in the Croatian endemic area to be 3.75-fold the risk in Brod-Posavina County and 16.4-fold the risk in Croatia.

CONCLUSIONS

These results showed that specific mortality and morbidity as well as standardized morbidity ratio and standardized mortality ratio were higher in Croatian endemic area than in Brod-Posavina County and Croatia.

Balkan endemic nephropathy-current status and future perspectives

Balkan endemic nephropathy (BEN), originally described in 1956, is a unique familial, chronic renal disease encountered with a high-prevalence rate in Serbia, Bulgaria, Romania, Croatia and Bosnia and Herzegovina. The most prominent features of the disease are its endemic nature, long-incubation period, familial clustering of the disease and an unusually high incidence of associated upper urothelial cancer (UUC). There are no clear-cut data on BEN incidence and prevalence, since the studies carried out in different endemic areas yielded contradictory information. In spite of intermittent variations, the incidence of new cases has remained stable over time. It has been estimated that almost 100 000 people are at risk of BEN, whereas 25 000 have the disease. The clinical signs and symptoms of BEN are non-specific and often remain unrecognized for years. There are no pathognomonic diagnostic features of BEN, but the set of epidemiological, clinical and biochemical data along with the pattern of pathologic injury in the absence of any other renal diseases are highly suggestive of this entity. Although the aetiology has been extensively studied, fostering the publication of various hypotheses, only one of them has provided conclusive evidence related to the aetiology of BEN. Studies conducted over the past decade have provided particularly strong arguments that BEN and UUC are caused by chronic poisoning with aristolochic acids (AAs). In light of these later studies, one can raise the question whether AAs could be responsible for previously and currently widespread unrecognized global renal disease and UUC.

Balkan endemic nephropathy and associated urothelial cancer

Balkan endemic nephropathy (BEN) is a chronic tubulointerstitial disease described only in some rural parts of southeastern Europe. One of its most peculiar characteristics is a strong association with upper urothelial cancer (UUC). BEN-related UUC has the same histological features as other forms of UUC in general, but is more frequently bilateral, less frequently affects the bladder and has a sex ratio close to 1. BEN and BEN-associated UUC share the same etiology. Over time, incidence of these conditions has been declining. Since BEN was first described, around half a century ago, socioeconomic changes (in housing, farming, living standards, etc.) have been profound and have obscured the factors responsible for the observed reduction in incidence. Whatever the causes of BEN, the disease might not be restricted only to southeastern Europe. Rather, the intensity of exposure to risk factors for BEN and, consequently, clustering of cases has more likely determined our knowledge of topographical distribution of an etiological entity that is much more widespread, or that might even be ubiquitous in its sporadic form.