Association Between the Polymorphism of Angiotensin-Converting Enzyme Gene and Interleukin-1 Beta Gene and the Response to Erythropoietin Therapy in Dialysis Patients with Anemia.

Introduction: The polymorphism of the angiotensin-converting enzyme (ACE) gene and interleukin-1 beta (IL-1b) gene could be associated with resistance in the treatment of anemia in dialysis patients with recombinant human erythropoietin (rHuEPO). The aim of the study was to evaluate the association between the polymorphism of the ACE and IL-1b genes and the response to rHuEPO therapy in dialysis patients with anemia. Material and methods: The study investigated 69 patients on dialysis with anemia treated with recombinant human erythropoietin for 12 months. Genotyping of ACE and IL-1b polymorphism was done in all study patients at the initiation of the study. The patient's demographic characteristics, dialysis vintage, and laboratory parameters were also evaluated as factors associated with rHuEPO resistance. The erythropoietin resistance index (ERI) was calculated as the weekly rHuEPO dose per kg of body weight, divided by the hemoglobin (Hb) concentration in g/dl. Results: The Hb ≥ 110 g/l was registered in 37 (53.6%) patients. Patients with Hb ≥ 110 g/l were characterized by significantly higher serum levels of albumin, cholesterol, and iron than those with Hb < 110 g/l. The serum level of the CRP, the weekly dose of rHuEPO, and ERI were significantly higher in patients with Hb < 110 g/l compared to patients with Hb ≥ 110 g/l. The ERI value of ≥ 10 IUkg/weekly/g/dl was present in 27 (39.1%) patients. The serum levels of ferritin and CRP, and weekly dose of rHuEPO were significantly higher in patients with ERI value ≥ 10 IU kg/weekly/g/dl compared with the patients with ERI value < 10 IUkg/weekly/g/dl. There was no significant association between the ERI and polymorphism of the ACE and IL-1b genes in study patients. Conclusion: The polymorphism of the ACE and IL-1b genes was not significantly associated with the response to erythropoietin therapy in dialysis patients with anemia. Iron deficiency, malnutrition, and inflammation were factors associated with anemia and resistance to erythropoietin therapy in dialysis patients.

Diabetics on dialysis in the Republic of Macedonia: A nationwide epidemiological study.

BACKGROUND: Incidence increase of diabetes mellitus (DM) has taken epidemic proportions in the world. Diabetic nephropathy (DN) is a most serious complication, taking a leading place as a factor in the progression of chronic kidney disease (CKD). Dialysis treatment of these patients is complex, expensive, and exerts an excessive burden on the health budgets of the affected countries. METHODS: We performed a nationwide precise observational study with the aim of analysing diabetics on dialysis in dialysis centres throughout the Republic of Macedonia (RM) in 2002 and in 2006; to compare the results from patients records; and to gather data on the epidemiology, clinical characteristics and complications of diabetes type 1 (DM1) and diabetes type 2 (DM2). RESULTS: The prevalence of HD patients in RM was 1114 vs 1074 in 2002 and 2006, respectively. Of these, 109 (9.78%) vs. 115 (10.71%) had DM in 2002 and 2006, respectively. The percentage of diabetics on dialysis between different centers varied between 3% to 21% vs. 2.4% to 22.07% in 2002 and 2006, respectively. The mean age of the patients was 58+/-10.29 vs. 56.5+/-10.71 in 2002 and 2006, respectively. Patients with DM1 were 19 (17.43%) vs. 15 (13.04%) and with DM2 were 90 (82.57%) vs. 100 (86.96%) in 2002 and 2006, respectively. 28 (25.68%) vs. 31 (26.96%) patients were on oral anti-diabetic drugs and 62 (57.21%) vs. 69 (60%) patients were on insulin in 2002 and 2006, respectively. Mean age of DM1 patients was 47+/-11.6 y. vs. 45+/-7.32 y. respectively and of DM2 was 60.37+/-8.33 y. vs. 61.14+/-10.23 y., in 2002 and 2006, respectively. Mean time of insulin treatment was 9.5+/-6.63 y. vs. 10.85+/-9.29 y. in 2002 and 2006. Mean Body Mass Index (BMI) was 26.4 vs. 23.49+/-4.74 kg/m2 in DM1 and 25.5 vs. 24.77+/-3.70 kg/m2 in DM2 patients in 2002 and 2006, respectively. Thrombosis of first arteriovenous fistulae (AVF) occurred in 41% vs. 25.22% in 2002 and 2006, respecttitvely. Hepatitis C virus (HCV) infection was confirmed in 57% vs. 44% of DM patients in 2002 and 2006, respectively. Most common co-morbidity in patients was hypertension, 91% vs. 80.87% in 2002 and 2006, respectively. CONCLUSION: The number of diabetics on dialysis in the Republic of Macedonia did not increase in the period from 2002 to 2006. In DM2 diabetics on dialysis the frequency of complications is higher and time on dialysis is shorter than in DM1 patients. Early detection of diabetic nephropathy by primary care physicians as well as collaborative treatment by diabetologists, nephrologists, cardiologists and ophthalmologists before and during dialysis are important for improvement of treatment and survival of diabetic patients on dialysis.

Atherosclerosis and vascular calcification in uraemia - a new experimental model.

Cardiovascular disease (CVD) is the most frequent cause of morbidity and mortality in chronic renal failure (CRF) patients. Accelerated calcifying atherosclerosis, medial calcification, and valvular calcification are hallmarks of CVD in the dialysis population. The mechanisms by which uraemia promotes vascular calcification and the relationship between arterial wall calcification and atherosclerosis are poorly understood. We surgically induced CRF in apolipoprotein E knockout (apoE-/-) mice to study a possible acceleration of aortic atherosclerosis, the degree and type of vascular calcification as well as factors involved in the calcification process. Finally we investigated appropriate treatment measures. Atherosclerotic lesions in the thoracic aorta were significantly larger in uraemic apoE-/- mice than in non-uraemic controls. The relative proportion of the calcified area to the total surface area of both atherosclerotic lesions and lesion-free vascular tissue was increased in the aortic root of uraemic apoE-/- mice when compared with controls. The accelerated atherosclerosis was associated with an increase in aortic nitrotyrosine expression, indicating enhanced oxidative stress, and an increase in plaque collagen content, indicating changes in plaque composition. N-acetylcysteine (NAC) treatment slowed the rapid progression of atherosclerotic lesions and reversed the increase in plaque collagen content compared with placebo treatment. NAC-treatment also reduced nitrotyrosine expression in uremic apoE-/- mice whereas the degree of macrophage infiltration was unchanged. Sevelamer treatment delayed not only vascular calcification but also atherosclerotic lesion progression in uraemic apoE-/- mice. These treatment effects also were associated with diminished oxidative stress and were independent of cholesterol lowering. We anticipate that this experimental model will prove to be useful to test other treatment strategies aimed at decreasing the accelerated atherosclerosis and arterial calcification of the uraemic state.

Pleiotropic effects of the non-calcium phosphate binder sevelamer.

The number of chronic kidney disease (CKD) patients and related adverse outcomes has dramatically increased worldwide in the past decade. Therefore, numerous experimental and clinical studies have recently addressed the underlying mechanisms, in particular the marked increase in cardiovascular mortality. Hyperphosphatemia is a major problem in these patients with advanced stage of CKD. Its control by calcium-containing phosphate binders is effective, but at the price of potentially noxious calcium overload. Sevelamer hydrochloride is a phosphate binder that offers an effective control of hyperphosphatemia as calcium-rich binders but without increase of calcium load. Beyond the control of phosphate, sevelamer seems to exert pleiotropic effects which include the correction of lipid abnormalities and the clearance of some uremic toxins.

Malnutrition inflammation complex syndrome in maintenance haemodialysis patients.

Malnutrition inflammation complex syndrome (MICS) occurs in maintenance haemodialysis (MHD) patients and is a strong predictor of morbidity and mortality in these patients. The aim of our study was to evaluate the influence of inflammation on the biochemical and anthropometrical parameters of the nutritional status in MHD patients. Our study was made on 154 patients (93 men and 61 women, mean age=54.7 yrs. and mean time on dialysis 84 months) over a period of 6 months. The indicator of inflammation, C-reactive protein (CRP), was measured monthly at the central laboratory by nephelometry. The assessment tools used to evaluate the influence of inflammation on the nutritional status in MHD patients were: serum albumin and cholesterol level, midarm circumference (MAC), midarm muscle circumference (MAMC), triceps skin fold thickness (TSF) and body mass index (BMI). Student's t-test was used for group mean comparison between men and women. Person's correlation r was used to determine the significance and the strength of associations. The CRP level was significantly greater in men than in women (12.9 vs. 7.97, p < 0.04). The CRP level showed a strong correlation only with the serum concentration of cholesterol (r=0.49, p < 0.000), and did not correlate with the serum albumin of the MHD patients. There was no correlation between the CRP level and the anthropometrical parameters of the MHD patients in our study. Two separate processes, inflammation and reduced protein intake, each separately contributed to causing a decrease in serum albumin concentration and anthropometrical measurements. The levels of acute phase proteins vary widely as opposed to the serum albumin level; for that reason, changes in the albumin catabolic rate or synthesis require a considerable time to become visible. The average value of the protein catabolic rate of the patients in our study was 1.01 g/kg/d, a value that showed adequate protein intake. These findings would suggest that clinical attention to the maintenance of adequate nutrition could blunt the effects of inflammation on both somatic and visceral protein stores.

Histomorphometric analysis of fibrosis in the renal interstitial compartment.

The interstitium is the extravascular intertubular space of the renal parenchyma, which provides structural support to the functional renal units and is included at the same time in nearly all renal functions. Alterations to this renal compartment have been found in almost all glomerular diseases. During the last thirty years the studies of a few groups of investigators have shown that the degree of the renal dysfunction is strongly correlated with the changes in the tubulointerstitial compartment. We made a morphometric study of a group of 10 renal biopsies, previously diagnosed as IgA nephropathy or membranoproliferative glomerulonephritis. For morphometric analysis we made colour extraction of the interstitial area on tissue sections stained with trichrom Masson using the LUCIA M-NIKON image analysing system with integrated software for statistical analysis of the data. We measured the surface of the marked fields and the results were expressed as a percentage of the total scanned area. The results were correlated with the serum creatinine at the time of biopsy. We found fibrosis occupying more than 10% of the tubulointerstitial surface in all 10 patients. Six of them had a moderate level of fibrosis, occupying more that 20% of the tubulointerstitial space. The statistical analysis of these results showed a significant correlation between the degree of the interstitial expansion and the serum creatinine. The results showing the correlation between these parameters will enable the quantitative histological analyses to be included in the process of the nephropathological diagnosis in order to evaluate the histological risk factors in glomerular diseases.

Molecular and epidemiological approaches to the etiology of urinary tract tumors in an area with Balkan endemic nephropathy.

Recently, we completed a second biostatistical study of urinary tract tumors (UTT) in areas with Balkan endemic nephropathy (BEN) in the Vratza district, Bulgaria, during the period 1975 to 1991. We confirmed the positive correlation between the incidence of urinary tract tumors (UTT) and BEN demonstrated in our first population-based case control 1977 study. A UTT incidence of 98.9 per 100,000 men and 74.7 per 100,000 women was found in villages most affected by BEN when compared with 11.0 and 6.7 for men and women, respectively, in nonendemic villages. The relative risk (RR) of UTT in BEN villages showed tumors of kidney pelvis and ureters-29 in men and 35 in women and urinary bladder tumors-4 in men and 11 in women. The percentage of food and blood samples containing nephrotoxic and carcinogenic mycotoxin Ochratoxin A (OTA) correlated with the origin of the samples. The most contaminated samples were found in BEN villages and households, and the urinary excretion of OTA was higher in the group of BEN/UTT patients. The UTT DNA's were studied by the 32P-postlabeling method for the presence of OTA-DNA adducts. Some OTA-DNA adducts characteristic for endemic UTT and absent in control nonendemic UTT and nontumorous tissues were described for the first time.

Genetic predisposition to Balkan endemic nephropathy: ability to hydroxylate debrisoquine as a host risk factor.

The objective of this study was to examine the association between efficiency of oxidative metabolism and risk for developing Balkan endemic nephropathy (BEN) and/or transitional-cell carcinoma of the urinary tract, using a case-control design controlling for age, gender and socioeconomic factors. Over 900 urine samples were taken from 646 subjects, divided into the following groups: healthy subjects from areas with no BEN; healthy subjects from villages with BEN; subjects suspected of having BEN; and subjects with BEN and/or upper urinary tract tumours (UUT). BEN patients and controls from the same villages were of similar age. The highest urinary recovery of debrisoquine was found among controls from areas with no BEN; recovery in BEN patients was only 50% of that in controls. The most interesting result is that BEN patients did not have impaired debrisoquine metabolism: subjects who metabolized less than 25% of the drug represented only 2.9% of BEN patients, 12.4% of controls from BEN villages and 12.7% of controls from outside the BEN area. The very poor metabolizers represented 1.0% of BEN patients and 4.8-5.8% of controls. the percentages of extensive metabolizers in the same groups were 86.3, 64.5 and 67.4%, respectively. The mean metabolic ratio rose progressively from BEN patients less than suspected BEN patients less than controls from BEN villages less than controls from non-BEN villages; the maximum metabolic ratios were 40, 51, 72 and 87, respectively. The cumulative distribution of the 8-h urinary debrisoquine metabolic ratios, presented as a normal probability plot, formed a discrete population with values over 10. The distribution among patients with BEN/UUT indicates a predominance of extensive debrisoquine hydroxylation and a lack of poor metabolizers. These results are consistent with the hypothesis that the efficiency of oxidative metabolism is greater in BEN patients and that it may be one of the key host factors determining predisposition to these diseases.

Partial hepatectomy and liver regeneration in Syrian hamsters.

In Syrian hamsters 74-75% removal of the liver led to 8-10% mortality. Cell mitosis increased at 36-42 hours after the operation and reached a peak of 43-51% during the 3rd day. Individual variations in liver weight as well as in number of mitosis were smaller in 2-3 months old hamsters than in 6-12 months old animals.

Familial aggregation of urinary system tumors in a region with endemic nephropathy.

In hyperendemic villages in the Vratza district of Bulgaria, 193 patients with urinary system tumors (UST) were diagnosed during 1965 to 1976. A tendency towards familial aggregation was revealed when the patients were compared with two groups of controls, namely, patients with tumors other than UST and healthy persons. Each control group consisted of 193 persons matched by sex, age, and place of birth. This tendency was observed in all relatives who lived together as well as in those related by blood. The probability of having relatives with UST was 2.5 times higher than could be expected as chance occurrence among UST patients than among the controls. The UST cases also had significantly more relatives with endemic nephropathy than did the controls. The familial clustering of both UST and nephropathy in the endemic region is considered another clue to their common etiology.

Epidemiologic data for environmental determination of urinary system tumours and nephropathy in an endemic region.

One hundred and thirty-eight patients diagnosed for urinary system tumours (UST), 714 patients with endemic nephropathy (EN) and 55 cases of UST and EN combined, all from endemic villages of Vratza district, Bulgaria were investigated for their familial pattern and time of diagnosis compared with the age at diagnosis. There were 144 spouses among these patients and nearly half of them came from non-endemic families and villages. The familial pattern followed the size of the population found to be at greater risk, i.e. people 40-60 years old, in particular women. Among the investigated 91 pairs of parents and children and 166 pairs of siblings the mean diagnostic interval was shorter than the mean difference of age at diagnosis. Therefore the epidemiologic data provide support to the hypothesis that possibly environment plays a predominant role in the familial aggregation and in the etiology of UST and EN in the endemic region.

[Malignant tumors in a region of endemic nephropathy]. / Zlokachestvennye opukholi v raione éndemicheskoi nefropatii.

In villages with endemic nephropathy (EN) high incidence and mortality rates of some urinary system tumors are reported. Age-adjusted incidences of renal pelvic and ureteral neoplasms were 46/10(5) in females and 27/10(5) in males; for urinary bladder tumors these figures were 16/10(5) and 35/10(5). The frequency of parenchymal kidney tumors was similar to that reported for the country as a whole. An increased relative risk of developing urinary system tumors was observed in patients with EN and with advancing age (only in women). Smoking did not relate to the occurrence of these neoplasms. No tumors of the urinary system were found in the investigated farm and domestic animals from the endemic region.

Families with multiple cases of urinary system tumors: brief communication.

A study of three families living in villages with endemic nephropathy (EN) in Vratza district, Bulgaria, revealed 9 members with urinary system tumors (UST), 7 with UST and EN, and 7 with EN. Most cases were registered from 1962 to 1976. The predominant form was transitional cell neoplasms of the kidney pelvis and ureter in patients 40-60 years old. In about 40% of the patients more than one site in the urinary system was involved. One ovarian carcinoma was also registered in these families during this period. Persons related by marriage and coming from nonendemic families and villages were also affected by both diseases. In other branches of the three families living in other households or villages, only one case of EN was found.