[show abstract][hide abstract] ABSTRACT: Cardiovascular diseases are more prevalent in patients with chronic kidney disease than in the general population and they are considered the leading cause of death in patients with end-stage renal disease. The discovery that vitamin D3 plays a considerable role in cardiovascular protection has led, in recent years, to an increase in the administration of therapies based on the use of this molecule; nevertheless, several studies warned that an excess of vitamin D3 may increase the risk of hypercalcemia and vascular calcifications. In this study we evaluated the effects of vitamin D3, and of its selective analog paricalcitol, on immature cardiomyocytes. Results show that vitamin D3 induces cAMP-mediated cell proliferation and significant intracellular calcification. Paricalcitol, however, induces cell differentiation, morphological modifications in cell shape and size, and no intracellular calcification. Furthermore, vitamin D3 and paricalcitol differently affect cardiomyoblasts responses to acetylcholine treatment. In conclusion, our results demonstrate that the effects of vitamin D3 and paricalcitol on cardiomyoblasts are different and, if these in vitro observations could be extrapolated in vivo, they suggest that paricalcitol has the potential for cardiovascular protection without the risk of inducing intracellular calcification.
[show abstract][hide abstract] ABSTRACT: In addition to its role in calcium homeostasis and bone mineralization, vitamin D is involved in immune defence, cardiovascular function, inflammation and angiogenesis, and these pleiotropic effects are of interested in the treatment of chronic kidney disease. Here we investigated the effects of paricalcitol, a nonhypercalcemic vitamin D analogue, on human peripheral blood mononuclear cell proliferation and signaling, and on angiogenesis. These effects were compared with those of a known inhibitor of angiogenesis pertaining to the vitamin D axis, the vitamin D-binding protein-derived Gc-macrophage activating factor (GcMAF).
Since the effects of vitamin D receptor agonists are associated with polymorphisms of the gene coding for the receptor, we measured the effects of both compounds on mononuclear cells harvested from subjects harboring different BsmI polymorphisms.
Paricalcitol inhibited mononuclear cell viability with the bb genotype showing the highest effect. GcMAF, on the contrary, stimulated cell proliferation, with the bb genotype showing the highest stimulatory effect. Both compounds stimulated 3'-5'-cyclic adenosine monophosphate formation in mononuclear cells with the highest effect on the bb genotype. Paricalcitol and GcMAF inhibited the angiogenesis induced by proinflammatory prostaglandin E1.
Polymorphisms of the vitamin D receptor gene, known to be associated with the highest responses to vitamin D receptor agonists, are also associated with the highest responses to GcMAF. These results highlight the role of the vitamin D axis in chronic kidney disease, an axis which includes vitamin D, its receptor and vitamin D-binding protein-derived GcMAF.
Journal of nephrology 09/2011; 25(4):577-81. · 2.02 Impact Factor
[show abstract][hide abstract] ABSTRACT: Dialysis patients exhibit a higher morbidity and mortality rate than those in the general population of comparable age. Survival on dialysis has become significantly longer and is mainly related to comorbid factors. Patients are usually the main research subjects, but caregivers play a pivotal role in patients' well-being. Here we describe the remarkable case of wife and husband both on hemodialysis for 32 years.
Hemodialysis International 05/2008; 12(2):233-5. · 1.44 Impact Factor
[show abstract][hide abstract] ABSTRACT: Cardiovascular disease caused by accelerated atherosclerosis is the major determinant of morbidity and mortality in chronic kidney disease patients. Vitamin D and its analogs provide survival benefit for hemodialysis (HD) patients. Vitamin D exerts its effects through the vitamin D receptor (VDR) that is coded for by a gene showing several polymorphisms that, in turn, are associated with a variety of diseases and differential responses to vitamin D. In this study, we evaluated the association between 4 VDR polymorphisms (ie, those identified by the restriction enzymes BsmI, ApaI, TaqI, and FokI) and iron indices (serum iron, transferrin, transferrin saturation, and ferritin) in 88 hemodialysis patients routinely treated with vitamin D. The absence or presence of the BsmI, ApaI, TaqI, and FokI restriction sites were denominated B and b, A and a, T and t, F and f, respectively. Our results show that in HD patients with transferrin saturation <20%, the F allele was more frequent than in HD patients with transferrin saturation >20% (P = .03). This relationship may provide a link between VDR alleles and iron and nutritional markers, which are highly predictive variables of cardiovascular morbidity and mortality in hemodialysis patients.
[show abstract][hide abstract] ABSTRACT: Cardiovascular disease due to atherosclerosis is the major determinant of morbidity and mortality in uremic patients. Inflammation is essential in the development of atherosclerosis and markers of inflammation, in particular C-reactive protein, predict the cardiovascular risk. Vitamin D exerts its effects through the Vitamin D Receptor, coded for by a gene showing several polymorphisms associated with a variety of diseases and differential responses to Vitamin D. We evaluated the association between four Vitamin D Receptor polymorphisms (i.e. those identified by the restriction enzymes BsmI, ApaI, TaqI and FokI) and serum level of C-reactive protein in 88 hemodialysis patients routinely treated with active Vitamin D (calcitriol). Absence or presence of the BsmI, ApaI, TaqI, and FokI restriction sites were denominated B and b, A and a, T and t, F and f respectively. Our results show that the b, a, T, alleles were more frequent in patients with elevated serum level of C-reactive protein compared with patients with normal C-reactive protein level. The differences were statistically significant (p < 0.05). These results suggest that the Vitamin D Receptor alleles b, a, T could be considered novel risk factors in the pathogenesis of inflammation-related, atherosclerosis-dependent cardiovascular disease risk in uremic patients.
Italian journal of anatomy and embryology = Archivio italiano di anatomia ed embriologia 01/2008; 113(1):55-62.
[show abstract][hide abstract] ABSTRACT: Chronic kidney disease patients who are resistant to erythropoietin (EPO) treatment may suffer from malnutrition and/or inflammation.
In a cross-sectional study of haemodialysis patients, we investigated the relationship between the natural logarithm of the weekly EPO dose normalized for post-dialysis body weight and outcome measures of nutrition and/or inflammation [BMI, albumin and C reactive protein (CRP)] by means of multiple linear regression analysis. On the basis of the decile distribution of weekly EPO doses, we also evaluated four groups of patients: untreated, hyper-responders, normo-responders and hypo-responders.
Six hundred and seventy-seven adult haemodialysis patients were recruited from five Italian centres. BMI and albumin were lower in the hypo-responders than in the other groups (21.3+/-3.8 vs 24.4+/-4.7 kg/m(2), P<0.001; and 3.8+/-0.6 vs 4.1+/-0.4 g/dl, P<0.001), whereas the median CRP level was higher (1.9 vs 0.8 mg/dl, P = 0.004). The median weekly EPO dose ranged from 30 IU/kg/week in the hyper-responsive group to 263 IU/kg/week in the hypo-responsive group. Transferrin saturation linearly decreased from the hyper- to hypo-responsive group (37+/-15 to 25+/-10%, P = 0.003), without any differences in transferrin levels. Ferritin levels were lower in the hypo-responsive than in the other patients (median 318 vs 445 ng/ml, P = 0.01). At multiple linear regression analysis, haemoglobin, BMI, albumin, CRP and serum iron levels were independently associated with the natural logarithm of the weekly EPO dose (R(2) = 0.22).
Our findings support a clear association between EPO responsiveness and nutritional and inflammation variables in haemodialysis patients; iron deficiency is still a major cause of hypo-responsiveness.
[show abstract][hide abstract] ABSTRACT: Pure red-cell aplasia (PRCA) in recombinant human erythropoietin (rHuEpo) treated patients is a matter of growing concern. In most cases, neutralizing anti-EPO antibodies have been detected in patient serum and held responsible for the development of PRCA. We describe a 68-year-old white woman suffering from HCV-related cryoglobulinemia and chronic kidney disease on renal replacement therapy with peritoneal dialysis. Five months after the introduction of epoetin-b therapy she developed a PRCA, as shown by the bone marrow aspirate. Cryocrit rose from 5% to 15% at this time, reticulocyte count fell, while white blood cells and platelets remained within normal values. Epoetin-b therapy was discontinued and steroid treatment was started. The test for anti-erythropoietin antibodies was negative. Hemoglobin and reticulocytes progressively rose and steroid therapy was tapered and eventually stopped, when the cryocrit was 3%. We propose that a relapse in the HCV-related cryoglobulinemia might be held responsible for the erythropoietic marrow failure.
Journal of nephrology 01/2004; 17(5):744-6. · 2.02 Impact Factor
[show abstract][hide abstract] ABSTRACT: To study the distribution of vitamin D receptor (VDR) gene alleles in hypercalciuric and nonhypercalciuric nephrolithiasis patients, hypothesizing that distinct biochemical parameters would be associated with different VDR genotypes.
12 hypercalciuric, 15 normocalciuric nephrolithiasis patients, and 150 healthy subjects were recruited. The individual genetic pattern for VDR was evaluated by DNA extraction followed by polymerase chain reaction amplification of the VDR gene and digestion with the restriction enzyme BsmI.
In the hypercalciuric group, Bb patients represented 50% (6/12); bb patients 33% (4/12), and BB cases were 16% (2/12). The VDR frequency distribution was not statistically different in hypercalciuric patients and controls (Bb 72%; bb 16%; BB 12%). In the nonhypercalciuric group, the prevalence of the bb genotype (7/15; 47%) was thrice the percentage of control subjects, while the percentage of BB patients was similar to that of the control group (2/15; 13%). Patients with the bb haplotype exhibited a higher daily urinary calcium excretion. Among hypercalciuric patients, after a calcium-restricted diet, bb patients showed a 39% reduction in daily urinary calcium excretion in comparison with a nonsignificant 13% reduction observed in BB subjects (p = 0.004).
The effects of VDR gene polymorphism on calcium metabolism contribute to the understanding of the pathogenesis of urinary calculi.
Mineral and Electrolyte Metabolism 01/1999; 25(3):185-90.
[show abstract][hide abstract] ABSTRACT: In this study we investigated the effect of different dialysis membranes on the clonal murine haematopoietic cell line 32D cells transmembrane signalling machinary, monitored by 1,2-diacylglycerol (DAG) formation, and on their ability to respond to the physiological growth factor interleukin-3 (IL-3).
Cells were exposed to dialysers (cuprophane, CU; polysulphone, PS; cellulose diacetate, CA; polyacrylonitrile, AN69; polymethylmethacrylate, PMMA; cellulose triacetate, CT; polyamide, PA; and polycarbonate, PC); they were collected, counted, and treated with physiological amount of IL-3. Cell proliferation was monitored as incorporation of radioactivity in duplicating DNA. DAG was measured by thin-layer chromatography in cell labelled with tritiated glycerol overnight.
CU and PA stimulated cell proliferation in comparison with resting cells. PS and TC did not significantly affect thymidine incorporation either in IL-3-stimulated, or in resting cells. Cells exposed to AN69, PC, and CA showed depressed basal incorporation of thymidine (70, 54 and 56% of controls respectively) but retained the ability to respond to IL-3 in a manner not statistically different from controls. PMMA reduced thymidine incorporation both in basal condition and after IL-3 stimulation CU and PC activated early cell signalling (1.95 x and 1.31 x respectively, DAG increase over control), while PA and TC depressed DAG generation (0.38 x and 0.47 x respectively, DAG increase over control). PS, CA, AN69, and PMMA did not stimulate DAG generation.
Alternations of intracellular mitogenic signalling appear to correlate with the ability to make a cell competent for function. These results might help to elucidate the effect of different dialysers, at the molecular level, on the blood cell behaviour in vivo.
[show abstract][hide abstract] ABSTRACT: A number of agents stimulate transmembrane cell-signaling in different cell types through the formation of the second messenger diacylglycerol (DAG) which activates protein kinase C (PKC). The aim of this study was to investigate phospholipase C activation, DAG formation, and cellular adhesion to dialysis membranes after simulated dialytic treatment of either human leukocytes or clonal hematopoietic cells. Cells were circulated for 60 minutes in a closed-loop dialysis system using three different dialyzers: cuprophan (CU), polysulphone (PS), and AN69 (PAN). Another cell aliquot was left within the dialyzers without circulation. Samples were taken at different time intervals and cells counted. Cells were labeled with tritiated glycerol overnight, and DAG was measured by thin-layer chromatography. Our data showed that cells tended to adhere with more efficiency to CU than to the synthetic dialyzers. Circulation in the in vitro dialysis circuit resulted in the rapid (5 min) formation of [3H]DAG (CU 1.95-; PS 1.34-; PAN 1.24-fold increase over untreated cells). The DAG level peaked at 15 to 30 minutes and remained constant thereafter (CU 1.70; PS 1.96; PAN 1.66). When we measured DAG formation in cells that had been kept in the dialyzers without circulation, we found that cells exposed to CU showed a much higher and rapid activation than those exposed to PS or PAN, as if CU per se was able to activate early cell signaling (CU 1.95-; PS 0.97-; PAN 1.09-; DAG, -fold increase over control).(ABSTRACT TRUNCATED AT 250 WORDS)
Kidney International 09/1994; 46(2):461-6. · 7.92 Impact Factor
[show abstract][hide abstract] ABSTRACT: In a crossover study conducted with eight uremic patients maintained on hemodialysis, the Authors compared the effects of heparin (100 IU/kg at the start of dialysis) and defibrotide (400 mg at the start, repeated at 2 hours of ongoing dialysis) on the parameters of blood coagulation (VIII:C, AT III, TAT, PC antigen and activity, PS, and FPA), each being assessed before dialysis and at 2, 3 and 4 hours of the ongoing procedure. Heparin-assisted dialysis resulted in a significant rise of VIII:C and AT III; with defibrotide, instead, there was evidence of thrombin activation (increased FPA and TAT). PC levels were raised with both dialysis modalities; however, PC activity and PS levels were increased only in defibrotide-assisted dialysis. There were no adverse reactions or evidence of fibrin formation. These results confirm the antithrombotic activity of defibrotide in the course of dialysis and indicate that this action is independent of thrombin neutralization.
The International journal of artificial organs 11/1992; 15(10):590-4. · 1.76 Impact Factor
[show abstract][hide abstract] ABSTRACT: Incidence of seroconversion to anti-HCV from December 1989 to May 1991 was evaluated in patients and in their sexual partners. In December '89, 13 of 66 and in May '91, 26 of 75 patients were HCV positive. 9 of 13 new, seroconverted patients had been transfused. Seroconverted mean dialytic age was lower than that of previous HCV-positive patients. All the sexual partners were HCV negative. Blood transfusion seems to be the main risk factor for HCV infection, while environmental contamination is still debatable.
[show abstract][hide abstract] ABSTRACT: Intradialytic hypoxemia, leukopenia and coagulation system activation were monitored in 9 uremic patients during hemodialysis with cuprophane (Cu) and polysulfone (Psf) membranes, using the following parameters: polymorphonuclear count (PMN), elastase alpha-1 proteinase inhibitor (EI-alpha 1PI) complex, platelet count, beta-thromboglobulin (BTG), fibronectin (FN) and arterial oxygen tension (PaO2). Our results indicate that 1) intradialytic hypoxemia observed with both membranes does not seem to be exclusively related to the well-known membrane-dependent leukopenia; 2) platelet activation, as demonstrated by the plasma BTG increase, appears to be an exclusive cellulosic membrane-related phenomenon; 3) at the same time platelet activation seems to be the major factor responsible for high FN levels, the highest FN levels occurring concurrently with the lowest platelet count.
The International journal of artificial organs 06/1988; 11(3):175-80. · 1.76 Impact Factor
[show abstract][hide abstract] ABSTRACT: This study investigates the Il-1 production in vitro by normal peripheral blood monocytes or non-T cells following contact with different dialysis membranes (cuprophan, polysulphone, polymethylmethacrylate and polyacrylonitrile), in the presence or absence of lipopolysaccharide. The results of this study show that the physical contact between dialysis membranes and Il-1 producing cells is not by itself able to induce abundant Il-1 production unless exogenous lipopolysaccharide is added. A modest Il-1 production, however, could be observed with synthetic membranes (polysulphone and polyacrylonitrile), but not with cellulose membranes (cuprophan). Used membranes are completely ineffective as a trigger of Il-1 synthesis.