Differences in Risk Factors and Prevalence of Vascular Calcification between Pre-Dialysis and Hemodialysis Balkan Nephropathy Patients.

Aims: The aim of this study was to compare the risk factors and prevalence of vascular calcification (VC) in pre-dialysis and hemodialysis (HD) patients with Balkan endemic nephropathy (BEN) or other kidney diseases (non-BEN). Materials and Methods: The study involved 115 patients, 32 pre-dialysis and 83 HD patients, separated into groups of BEN and non-BEN patients. In addition to interviews, objective examinations and laboratory analyses, VC was assessed using Adragao score. Results: Patients with BEN were significantly older in both groups, while pre-dialysis BEN patients had significantly lower systolic blood pressure, serum cholesterol and phosphorus levels, but higher urinary excretion of phosphorus than non-BEN patients. These differences were lost in HD groups. In pre-dialysis patients, prevalence of VC was lower in BEN than in non-BEN group and mean VC score differed significantly between them (2.8 (1.7) vs. 4.6 (1.8); p = 0.009). No significant difference in VC score was found between BEN and non-BEN patients on HD. Multivariate analysis showed that in pre-dialysis patients VC score >4 was associated with lower iPTH and higher serum cholesterol level, but in the HD group with higher serum triglyceride level and longer HD vintage. Conclusions: Lower prevalence of risk factors for VC in the BEN than non-BEN patients was found in pre-dialysis but not in HD group and this was reflected in the prevalence and severity of VC in the groups. Prevalence of VC and mean VC score were significantly lower in pre-dialysis BEN than in non-BEN patients but not for those on HD.

Upper Urinary Tract Urothelial Cancer in Croatian and Bosnian Endemic Nephropathy Regions.

OBJECTIVES: Endemic nephropathy (EN) is a chronic tubulointerstitial renal disease associated with increased incidence of upper urinary tract urothelial cancer (UTUC) occurring predominantly in geographically limited areas in villages along big Danube river. Based on results obtained by the research it is confirmed that aristolochic acid is causative agent of endemic nephropathy (EN). AIM: The aim of this study was to determine characteristics of UTUC in two endemic areas and analyze trends in 5-year period. METHODS: This study included all patients with UTUC with or without synchronous/metachronous urothelial cancer in urinary bladder, from Croatian and Bosnian EN and non-EN regions. We analyzed archival data bases from all patients with UTUC who were admitted and operated in Department for surgery and urology, General Hospital Josip Bencevic Slavonski Brod in the time period between 2005 and 2010. Analyzed groups of patients were divided and compared as EN group (that includes patients from Croatian and Bosnian EN region) and non-EN group (that includes patients from Croatian and Bosnian non-EN region). All surgical specimens were processed according to standardized pathological procedures. RESULTS: Comparing patients basic characteristics from Croatian and Bosnian EN region there was no significant difference in gender (females were more frequently affected in both EN regions, p=0.99) or age (p=0.43) of patients. We found higher blood levels of urea and creatinine in group of patients from Croatian EN region when compared with group of patients from Bosnian EN region but the difference was not statistically significant (p=0.79 and p=0.44, respectively). In patients from Croatian EN group Hemoglobin levels were significantly lower than levels from Bosnian EN region patients, p=0.0049. In group of patients from Bosnian EN region ureteral tumors were more frequently observed than in Croatian group of patients, when compared with renal pelvis tumors but the difference was not statistically significant (p=0.258). CONCLUSION: Our data showed some differences in tumor localization between to investigated, relatively nearly situated, EN regions in Croatia and Bosnia. Statistically significant difference in hemoglobin levels between Croatian and Bosnian EN regions that should be further analyzed to give some reasonable explanation.

Prevalence and risk factors of vascular calcification in pre-dialysis patients with Balkan endemic nephropathy.

Introduction: Vascular calcifications (VC) are common in patients with chronic kidney disease and present one of manifestations of mineral and bone disorders in these patients. Objective: The aim of this pilot study was to examine the prevalence and risk factors of VC in pre-dialysis patients with Balkan endemic nephropathy (BEN) and other kidney diseases. Methods: The study involved 32 pre-dialysis patients, 15 with BEN and 17 with other kidney diseases. All the patients underwent an interview, objective examination, routine laboratory analyses and measurement of serum concentration of intact parathyroid hormone (iPTH), 25-hydroxyvitamin D3 [25(OH)D3] and osteopontin. VCs in iliac, femoral, radial, and digital arteries were evaluated and Adragao VC score was calculated. The samples of radial artery were collected during the first creation of an arteriovenous fistula, and expression of osteocalcin, bone morphogenic protein-2 osteopontin, and matrix Gla-protein in arterial wall were examined. Results: Patients with BEN were significantly older (71.1 ± 6.1 vs. 54.7 ± 11.1 years), but they had significantly lower systolic and mean blood pressure (95.7 ± 13.2 mmHg vs. 104.3 ± 7.4 mmHg) and lower serum concentration of phosphorus (1.32 ± 0.36 mmol/l vs. 1.65 ± 0.35 mmol/l) and cholesterol (4.3 ± 1.1 mmol/l vs. 5.2 ± 0.8 mmol/l) than patients with other kidney diseases. Mean VC score was significantly lower in patients with BEN than in those with other kidney diseases (2.8 ± 1.7 vs. 4.6 ± 1.8; p = 0.009), but expression of four examined proteins in arterial wall differed insignificantly between the two groups. VC score correlated significantly with serum concentrations of cholesterol, triglycerides (positively), and iPTH (negatively). Conclusion: Pre-dialysis BEN patients had a significantly lower mean score of VC than patients with other kidney diseases.

Ocular fundus abnormalities in patients with Balkan endemic nephropathy and other chronic kidney diseases.

AIM: The aim of this study was to examine the ocular fundus pathology in patients with Balkan endemic nephropathy (BN) and chronic kidney diseases (CKD). METHODS: The study included 51 patients with BN from the South Morava River region in Serbia, and 102 subjects with different stages of chronic renal diseases, matched according to age and gender, obtained from a database used in a recently published study. All patients had visited Outpatient Department of the Clinic of Nephrology, Clinical Center Nis. All patients underwent routine ophthalmic examinations. RESULTS: There were significantly more (P < 0.001) patients with age-related macular degeneration (AMD) in the group with BN (31.37 %) than in those with CKD (5.88 %). Multivariate logistic regression analysis confirmed that the significant factors related to AMD in the group with BN were albuminuria (P < 0.05) and proteinuria (P < 0.05); in CKD patients, the level of HDL (P < 0.05), while negative correlation with the level of triglyceride was registered (P < 0.05). There was no association between estimated glomerular filtration rate and AMD. The significant factors related to retinopathy in the group with BN are age (P < 0.05) and serum creatinine values (P < 0.05), in patients with CKD increasing age (P < 0.001) and DM (P < 0.05). CONCLUSION: Ocular fundus pathology in patients with BN is similar to the pathology of other CKD, but with significantly more AMD (about four times), probably related to the genetic/epigenetic factors.

Placental growth factor and placental protein 13 in patients with Balkan endemic nephropathy, a worldwide disease.

BACKGROUND: Balkan endemic nephropathy (BEN) is a chronic tubulointerstitial kidney disease occurring in people living in along the tributaries of the Danube River. The aim of the study was to determine serum level and urinary excretion of placental growth factor (PlGF) and placental protein 13 (PP13) in patients with BEN. METHODS: Thirty patients with BEN from the South Morava River region of Serbia and 18 controls were studied. Age of patients was 74 yr (53-87) and 73 yr (66-83) in controls. RESULTS: In patients with BEN, serum creatinine was significantly higher than in controls (129.7 vs. 83.2 µmol/L, respectively), but GFR was lower in patients than in controls (40.7 vs. 54.6 mL/min). Serum PlGF was significantly higher in BEN patients than in controls (9.90 vs. 6.80 pg/mL), urinary excretion being significantly lower in patients (0.20 vs. 0.90 pg/mmol creat.). Serum PP13 was significantly lower in BEN patients (208.2 vs. 291.0 pg/mL). Urinary excretion of PP13 was also significantly lower in BEN patients than in controls (32.5 vs. 182.5 pg/mmol creat). In multivariate regression analysis BEN, sex and age were significant determinants of the observed changes in PlGF and PP13. CONCLUSION: Important changes of PlGF and PP13 in patients with BEN were demonstrated, where kidney disease, female sex, and the age have been significant determinants.

Surprising good antioxidant status in patients with Balkan Endemic Nephropathy on hemodialysis undergoing vitamin C therapy. A pilot study.

AIMS: End Stage Renal Disease (ESRD) represents a microinflammatory state accompanied by oxidative stress and an imbalance between pro- and antioxidants. Vitamin C is a highly effective antioxidant, acting to lessen oxidative stress. The aim of our study was to assess the Antioxidant Capacity of Water soluble substances (ACW) and the Antioxidant Capacity of Liposoluble substances (ACL) in patients with Balkan Endemic Nephropathy (BEN) on hemodialysis undergoing Vitamin C therapy as compared to healthy controls. METHODS: Twenty-one patients with BEN on hemodialysis (HD), mean age: 63.33 +/- 5.42 years, 6 M and 15 F, were enrolled into the study. All patients received 10 vials of Vitamin C 750 mg/5 ml every 2 months. Eleven apparently healthy subjects, mean age: 63.73 +/- 5.21 years, 6 M and 5 F, served as controls. The photochemiluminescence assay was used to measure the antioxidant activity of plasma samples. The results are presented in equivalent concentration units of Vitamin C for water soluble antioxidants and in equivalent concentration units of Trolox (synthetic Vitamin E) for lipid soluble antioxidants. Both concentrations are expressed in micromols/L. Statistical analysis (non-parametric Wilcoxon test) was performed using NCSS. RESULTS: Mean duration since BEN diagnosis was: 8.24 +/- 3.5 years. Mean duration since HD initiation was: 4.92 +/- 3.4 years. Smoking status was negative in all patients. Hypertension was present in 15 patients (71.42%), cardiovascular disease in 10 (47.61%), HCV infection in 13 (61.9%), 1 patient had HBV + HCV infection, 1 had renal tuberculosis, 1 had upper urinary tract cancer, 1 genital cancer, and I autoimmune thyroid disease. The Antioxidant Capacity of Water soluble substances (ACW) in patients with BEN was 477.6 +/- 177.63 micromols/L, significantly higher as compared to controls: 198.05 +/- 196.63 micromols/L; p = 0.01, whereas the Antioxidant Capacity of Liposoluble substances (ACL) in patients with BEN was 33.9 +/- 22.99 micromols/L, non-significantly different as compared to controls: 27.38 +/- 4.21 micromols/L; p = 0.22. CONCLUSIONS: We conclude that Vitamin C therapy in patients with BEN on HD significantly increases the Antioxidant Capacity of Water soluble substances (ACW) as compared to controls and could be used to counter oxidative stress in patients with ESRD.

Therapeutic remedies based on Aristolochia clematitis in the main foci of Balkan endemic nephropathy in Romania.

Balkan endemic nephropathy (BEN) is a disease found in Romania and neighboring countries in the Balkan area. In Romania, BEN is most prevalent in Mehedinti County, located in the South of Romania near the Danube River. The etiology of the disease is as yet unknown. One of the current hypotheses concerning BEN etiology is an involvement of aristolochic acid (AA). BEN bears many similarities to aristolochic nephropathy, which is developed due to the use of Chinese herbs as therapeutic remedies in slimming diets. This paper analyzes the involvement of therapeutic remedies based on AA in the BEN found in Mehedinti County, where these herbs have been traditionally used. The presence of AA in the plasma of BEN patients as well as of other subjects, including healthy relatives of these patients and other persons from the BEN-affected area, has been analyzed. No AA was detected in the plasma of the studied subjects. This proves the absence, at the current time, of an AA contribution in the analyzed subjects. Therapeutic remedies based on AA have been used in the BEN-affected area. We were not able to reveal direct relationships between these remedies and either the development of BEN in dialyzed patients or the development of urinary-tract tumors in dialyzed patients with urothelial tumors. Therapeutic remedies based on Aristolochiaclematitis may play a stimulating role in BEN with regard to its development and the development of urinary-tract tumors. There may be a relationship between BEN and cumulative previous exposure to low doses of AA due to the consumption of contaminated foodstuffs, which could add to any contributions by therapeutic remedies.

Offspring of parents with Balkan Endemic Nephropathy have higher C-reactive protein levels suggestive of inflammatory processes: a longitudinal study.

BACKGROUND: Despite the characteristic extensive tubulointerstitial fibrosis, Balkan Endemic Nephropathy (BEN) is usually considered a non-inflammatory disease. METHODS: We examined a marker of inflammation, C-reactive protein (CRP), in the offspring of patients with BEN, a population at risk for BEN, prior to development of established disease to determine if an inflammatory process could be identified in the early stages of the disease. In 2003/04, 102 adult offspring whose parents had BEN and a control group of 99 adult offspring of non-BEN patients were enrolled in this prospective study. This cohort was re-examined yearly for four consecutive years. Levels of serum CRP were measured in years 3 and 4 and compared between groups. The data were analyzed with mixed models. RESULTS: Compared to controls, offspring of BEN parents had statistically higher CRP levels in two consecutive years, suggestive of early inflammatory reactivity. Whenever the mother was affected by BEN (both parents, or mother only), serum CRP was significantly increased, but not if only the father had BEN. CRP was inversely related to kidney cortex width but not to markers or renal function. CONCLUSION: Early stages of BEN may involve inflammatory processes. The observation of a maternal involvement supports the concept of fetal programming, which has been implicated in the pathogenesis of other chronic kidney diseases.

Transforming growth factor-beta 1 in Balkan endemic nephropathy.

BACKGROUND/AIM: The aim of this study was to compare plasma and urine transforming growth factor-beta1 (TGF-beta1) levels in patients with different stages of Balkan endemic nephropathy (BEN) with those in patients with primary glomerulonephritis (GN) and healthy controls. METHODS: The study involved 47 patients with BEN (30 with manifest BEN and 17 in the early stage of BEN), 12 patients with GN and 10 healthy controls. Plasma and urine TGF-beta1 was assayed by enzyme-linked immunosorbent assay. RESULTS: The median plasma TGF-beta1 levels differed nonsignificantly between the groups (4,908-6,442 pg/ml), but individual plasma TGF-beta1 levels in BEN patients exhibited the highest dispersion. Median urinary TGF-beta1 excretion (pg/mg creatinine) was significantly higher in patient groups (manifest BEN: 203, early-stage BEN: 341, GN: 775) than in healthy controls (42). No correlation was found between plasma and urine TGF-beta1 levels or between plasma TGF-beta1 levels and creatinine clearance for any of the examined groups. CONCLUSION: Plasma TGF-beta1 levels in BEN patients extended over the widest range, but no significant differences were found between the median values for the groups. Median urinary TGF-beta1 excretion was significantly higher in patients with BEN and GN than in healthy controls.

New data on the occurrence of ochratoxin A in human sera from patients affected or not by renal diseases in Tunisia.

Ochratoxin A is often found in the sera of people exposed to this mycotoxin in their food (cereals such as barley, coffee, wines, fruit juices, spices, products of animal origin such as pig and poultry offal). Ochratoxin A is suspected of playing a role in the Balkan Endemic Nephropathy, a nephropathology described in Balkan areas where ochratoxin A is often found in cereals and in pork-derived products. In North Africa like Tunisia where high incidence of chronic interstitial nephropathies of unknown aetiology are pointed out, the involvement of ochratoxin A was suspected but contradictory studies on the degree of human exposure did not succeed in evidencing the role of ochratoxin A. In the present work, sera from 47 volunteers hospitalised for nephropathic damages including bladder tumours (21 people), and from 62 patients hospitalised for disorders other than nephropathic ones, were analysed for ochratoxin A contents. The determination of ochratoxin A in sera was done by a validated immunoaffinity-HPLC method. Sera from unaffected population exhibited percentages of 74.2%, 22.6% and 3.2% containing ranges of ochratoxin A as <0.10-0.5 microg/l, 0.51-1.0 microg/l and above 1.0 microg/l respectively. For patients affected with renal diseases, percentages were 59.5%, 25.5% and 14.9% on the same ranges of ochratoxin A levels respectively. The average ochratoxin A concentration for patients with urinary tract disease excluding cancer patients was 0.99+/-1.28 microg/l while that for the non-nephropathic patients was 0.53+/-1.00 microg/l. However the average levels in the cancer patients was only 0.26+/-0.20 microg/l. Those results are in line with most of previously published works and did not confirm very high ochratoxin A contents found in other reports from same regions.

High-performance liquid chromatographic determination of sphinganine and sphingosine in serum and urine of subjects from an endemic nephropathy area in Croatia.

Endemic nephropathy (EN) is a chronic renal disease present as an endemic in Brodska Posavina, Croatia. The aim of the study was to assess the possible role of fumonisins, i.e., mycotoxins produced by Fusarium moniliforme, as causative agents for EN. Fumonisins inhibit ceramide synthase, the enzyme of de novo synthesis of sphingolipids, which leads to an increase in the sphinganine/sphingosine ratio. In the present study, a modified method has been used for the determination of the sphinganine/sphingosine ratio in human serum and urine of healthy subjects and EN patients from the endemic area. Free sphingoid bases, sphinganine and sphingosine, were obtained by base hydrolysis. Afterwards, precolumn ortho-phthaldialdehyde derivatisation, HPLC separation and quantification by fluorescence detection were performed. The results thus obtained pointed to a sphingolipid metabolism impairment, which may have been induced by fumonisins or fumonisin-like mycotoxins. As statistically significant differences were recorded in the subjects not yet affected with EN, an impairment in the metabolism of sphingolipids might be considered as an early indicator of EN.

Selenium-dependent and selenium-non-dependent glutathione peroxidase in patients with Balkan endemic nephropathy.

We studied the activity of erythrocyte selenium (Se)-dependent, Se-non-dependent glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) in uremic patients (UP) in clinically healthy members from families affected with Balkan nephropathy (HMF/BEN) and in healthy volunteers from endemic settlements (control group). The SOD activity was not significantly different in the groups studied and the Se-non-dependent GSH-Px activity in HMF/BEN and UP was not different from the control group. However, the activity of Se-dependent GSH-Px in UP was lower compared with the control group, whereas the mean value of the Se-dependent GSH-Px activity in HMF/BEN was not significantly different when compared with the other two investigated groups.

Elevated tumour markers in patients with Balkan endemic nephropathy.

Balkan nephropathy (BEN) is commonly associated with urothelial cancer. Urothelial cancer is manifested in the advanced stage of disease. The aim of this study was to facilitate early detection of urothelial cancer in BEN patients and their family members living in an endemic region by using tumour markers, carcinoembryonic antigen (CEA) and tissue polypeptide antigen (TPA), and a putative marker, ferritin. Fifteen BEN patients with normal renal function, 17 with renal failure (BEN-RF), 13 healthy members of their families (HFM), 14 patients with glomerulonephritis (GN) and 12 healthy controls (C) were studied. Serum CEA levels in BEN patients were within normal limits, however, in BEN-RF patients they were significantly increased over HFM (p<0.05). Serum TPA levels in BEN and BEN-RF patients were significantly higher than in the C and HFM groups (p<0.05). Urinary CEA was not significantly different between the groups studied. Urinary TPA levels in HFM (median 125 U/l, BEN (236 U/l) and BEN-RF (275 U/l) were significantly increased over C (30 U/l), however, TPA levels were increased also in GN patients (437 U/l). None of the BEN patients studied developed urothelial cancer during the ten years' follow-up. Markedly elevated urinary TPA-like levels in all patients studied (HFM, BEN, BEN-RF, GN) suggest that urinary TPA may not be a reliable tumour marker. However, the clinical relevance of high TPA levels in BEN patients should be evaluated.

Ochratoxin A in human sera in the area with endemic nephropathy in Croatia.

Ochratoxin A (OA) is nephrotoxic fungal metabolite (mycotoxin) occurring in foodstuffs. The compound is causally associated with mycotoxin porcine nephropathy, a disease comparable with a human kidney disease called endemic nephropathy (EN). In this paper we presented results obtained over a 10-year period in the hyperendemic village Kaniza, and in control villages where no clinical cases of nephropathy had been found. In the hyperendemic village Kaniza and non-endemic villages the incidence of OA in human blood was up to 4.5% (range 2-50 ng/ml) and up to 2.4% (range 2-10 ng/ml), respectively. Almost all samples of food and feed, collected randomly in the hyperendemic village were found to contain OA. Considering marked exposure to OA in Kaniza, it was assumed that incidence of EN in this population could be related to OA contamination of food and feed.

Serum angiotensin-converting enzyme activity in patients with endemic nephropathy.

Serum angiotensin-converting enzyme was measured in 60 patients with endemic nephropathy and in 30 healthy individuals. According to the arterial blood pressure, the patients with endemic nephropathy were further divided into groups with arterial hypertension (n = 30) and without arterial hypertension (n = 30). The activity of angiotensin-converting enzyme was determined by a spectrophotometric method using hippuryl-l-histidyl-l-leucine as a substrate. The serum activity of angiotensin-converting enzyme was significantly increased in the patients with endemic nephropathy (28.51 +/- 1.64 U/l) as compared with healthy individuals (20.83 +/- 1.33 U/l). The level of the enzyme was further increased if the endemic nephropathy was accompanied by arterial hypertension (37.09 +/- 1.45 U/l). The possible mechanisms of the increase in the angiotensin-converting enzyme activity are discussed.

[Erythrocyte catalase activity in patients with endemic nephropathy and in their family members]. / Aktivnost katalaze eritrocita kod bolesnika s endemskom nefropatijom i clanova njihovih porodica

Etiology and pathogenesis of endemic nephropathy (EN) are unknown and in this work the possible pathogenetic role of disturbed antioxidant protection, estimated by the activity of erythrocyte catalase, was evaluated. In patients with EN as well as in clinically healthy members of their families a statistically significant increase in catalase activity (16.7 +/- 0.63 x 10(4) U/g Hb) compared to the control group of the blood bank donors from the city of Nish (11.7 +/- 0.69 x 10 U/g Hb) was found. Increased catalase activity, at the level of significance, was also found in clinically healthy members of EN patients families. The increase of catalase activity was considered compensatory to the increased oxydative capacity.

Circulating inhibitor of interleukin 1 activity in patients with chronic renal diseases.

The effects of sera derived from patients suffering from chronic renal diseases (endemic Balkan nephropathy, glomerulonephritis and pyelonephritis) on T cell proliferative response was studied. It was found that these sera contained factors which affect interleukin 1 (IL-1) dependent events in T cell proliferative response. The factors prevent costimulatory effects of IL-1 on T cells but do not bind to IL-1, nor do they affect interleukin 2 (IL-2) dependent T cell proliferation. These findings indicate that immuno-suppression observed in some kidney disorders may be partially due to serum immunoinhibitory factors affecting IL-1 activity.

Selenium status of patients with Balkan endemic nephropathy.

The selenium (Se) contents in common cereals in endemic and nonendemic areas in Serbia are very low. Plasma Se levels of both patients and healthy subjects, were also low, reflecting low Se intakes. Patients with Balkan endemic nephropathy (BEN) had significantly lower (p less than 0.05) plasma Se levels than healthy individuals, both from regions close to endemic areas, and from Belgrade. Mean plasma Se of BEN patients was slightly but insignificantly higher in samples taken immediately after dialysis than in those taken before, suggesting that very little of the Se present in plasma is dialyzable. Plasma SeGSH-Px activities before and after hemodialysis in both BEN and Nonendemic chronic renal failure (NCRF) patients were not significantly different, but BEN patients had lower enzyme activities than those with NCRF and healthy controls. In BEN patients, a significant correlation between plasma Se and SeGSH-Px activity was found.