Ewa Baum

Hemodialysis-induced changes in the blood composition affect function of the endothelium

Hemodialysis induces oxidative stress causing intravascular inflammation, which may cause endothelial dysfunction. We evaluated how hemodialysis‐induced changes in blood affect the function of endothelial cells in in vitro culture. Serum samples were collected from 42 uremic patients treated with hemodialysis, one before the start of dialysis and the other one at the end of session. All patients were dialysed with polysulfone dialyzer. Concentrations of the inflammatory molecules carbonyl protein and metabolites of NO synthesis were measured in blood. Additionally, the effect of the serum obtained before and after dialysis on the function of endothelial cells in in vitro culture was studied. Hemodialysis caused increase of monocyte chemoattractant protein (MCP)‐1 (+17%), hepatocyte growth factor (+91%), and pentraxin‐3 (+30%) concentration in serum. Concentration of carbonyl protein was decreased by 30%. Decrease of blood level of asymmetric dimethylarginine (−25%) and nitrate/nitrites (−62%) was observed. Serum obtained after hemodialysis stimulated proliferation of endothelial cells (+10%) and synthesis of MCP‐1(+11%) in these cells. Hemodialysis‐induced intravascular inflammation changes the function of endothelial cells, which may lead to acceleration of atherosclerosis.

Animal Models of Peritoneal Dialysis: Thirty Years of Our Own Experience

Experimental animal models improve our understanding of technical problems in peritoneal dialysis PD, and such studies contribute to solving crucial clinical problems. We established an acute and chronic PD model in nonuremic and uremic rats. We observed that kinetics of PD in rats change as the animals are aging, and this effect is due not only to an increasing peritoneal surface area, but also to changes in the permeability of the peritoneum. Changes of the peritoneal permeability seen during chronic PD in rats are comparable to results obtained in humans treated with PD. Effluent dialysate can be drained repeatedly to measure concentration of various bioactive molecules and to correlate the results with the peritoneal permeability. Additionally we can study in in vitro conditions properties of the effluent dialysate on cultured peritoneal mesothelial cells or fibroblasts. We can evaluate acute and chronic effect of various additives to the dialysis fluid on function and permeability of the peritoneum. Results from such study are even more relevant to the clinical scenario when experiments are performed in uremic rats. Our experimental animal PD model not only helps to understand the pathophysiology of PD but also can be used for testing biocompatibility of new PD fluids.

Sulodexide modifies intravascular homeostasis what affects function of the endothelium.

PURPOSE Sulodexide is a mixture of heparin and dermatan sulphate which has an antithrombotic action. It was shown that it has also direct effect on the endothelial cells. We tested the effect of sulodexide on the intravascular homeostasis in patients with peripheral vascular disease. METHODS Sulodexide was infused iv. at a dose of 1200 Lipoprotein Lipase Releasing Units (LRU) in 10 patients with peripheral vascular disease. Blood samples were collected before the infusion and 1, 6 and 24 hours after the infusion. Inflammatory and fibrinolytic parameters were studied in the collected serum samples. Additionally, ex-vivo effect of the serum samples on in vitro function of the endothelial cells was studied. RESULTS Infusion of sulodexide caused acute and transient peak of the Hepatocyte Growth Factor (HGF) concentration in blood and decrease of the Vascular Endothelial Growth Factor (VEGF) level, what, as we found in in vitro experiments, was due to adsorption of VEGF to endothelium. We found that HGF enhanced in vitro stimulating effect of VEGF on proliferation of the endothelial cells. Serum level of interleukin-6 was gradually decreased, whereas fibrinolytic activity of serum, reflected by t-PA/PAI-1 ratio, increased. Serum samples obtained from the studied patients suppressed oxidative stress and release of interleukin-6 in endothelial cells maintained in in vitro culture. CONCLUSION Sulodexide reduces intravascular inflammation and suppresses inflammatory reaction in the endothelial cells; both effects are desirable in patients with peripheral vascular disease.

Sulodexide Reduces the Proinflammatory Effect of Serum from Patients with Peripheral Artery Disease in Human Arterial Endothelial Cells

Background/Aims: Dysfunction of the arterial endothelial cells promotes the progression of atherosclerosis. We studied how exposure of human arterial endothelial cells to atherosclerotic serum from patients with peripheral artery disease changes the secretory activity of these cells, and whether that reaction is modified by sulodexide. Methods: Endothelial cells in in vitro culture were exposed to standard culture medium ± 100pg/mL Interleukin-1(IL-1) or to medium supplemented with 20% atherosclerotic serum. Afterwards, the expression of genes responsible for the synthesis of Interleukin-6 (IL-6), Vascular Cell Adhesion Protein-1 (VCAM-1) and Von Willebrand Factor (VWF) was evaluated, together with the secretion of these compounds. Additionally, the effect of sulodexide on these processes was studied. Results: Atherosclerotic serum stimulated the expression of IL6, VCAM-1 and VWF genes in endothelial cells, which was followed by increased secretion of these compounds by 179%, 121% and 116%, respectively. Sulodexide (0.5 LRU/mL) reduced atherosclerotic serum-induced increased expression of genes for IL-6 (-32%), VCAM-1 (-20%) and VWF (-42%), and lowered secretion of these molecules: IL-6 (-27%), VCAM-1(-27%), VWF (-25%). Sulodexide also reduced, in a dose- dependent manner, secretion of IL6 from unstimulated and stimulated with IL-1 endothelial cells. Conclusions: Atherosclerotic serum induces proinflammatory and prothrombotic phenotype in arterial endothelium, which is partially reduced by sulodexide, via inhibition of genes expression, and in consequence lower secretory activity.

N‐Acetylglucosamine modulates function of the skin fibroblasts

Fibroblasts are an important component of the skin determining its properties. N‐Acetylglucosamine (NAG) is the substrate for hyaluronan synthesis, and it also has anti‐inflammatory and anti‐senescent activity in mesothelial cells.

Dialysis vintage stratified comparison of body composition, hydration and nutritional state in peritoneal dialysis and hemodialysis patients

Introduction Body mass decomposition and hydration state imbalances affect patients on maintenance dialysis. We compared body composition, hydration and nutritional state of patients on peritoneal dialysis (PD) and hemodialysis (HD) based on dialysis vintage (DV). Material and methods Three hundred and fifty-nine prevalent patients on HD (n = 301) and PD (n = 58) were divided into 3 subgroups depending on DV: < 2 years HD (n = 41) and PD (n = 28), 2–4 years HD (n = 111) and PD (n = 17), > 4 years HD (n = 149) and PD (n = 13). Bioimpedance analysis delivered data including overhydration (OH), Lean (LTM) and adipose lipids mass (FAT). Other measurements included daily diuresis (DD), subjective global assessment (SGA) and serum albumin (alb), C-reactive protein (CRP) and total cholesterol (TChol), and hemoglobin (Hb). Results Dialysis vintage < 2 years. Hemodialysis patients were older (65.5 ±18.5 vs. 50.9 ±17.1; p < 0.01) with a higher mortality (28 vs. 1; p < 0.01) and OH (8.0 ±4.3 vs. 1.6 ±3.1; p < 0.001). Hemoglobin (10.6 ±1.5 vs. 11.8 ±1.7; p < 0.05), TChol (180.2 ±47.0 vs. 211.7 ±46.3; p < 0.05), DD (871 ±729 vs. 1695 ±960; p < 0.001) and LTM (46.5 ±12.9 vs. 53.8 ±14.4; p < 0.05) were lower on HD. Dialysis vintage 2–4 years: when compared to PD, HD patients had higher OH (11.7 ±5.9 vs. 2.1 ±3.2; p < 0.001) and lower Hb (10.8 ±1.5 vs. 11.9 ±1.4; p < 0.01). Dialysis vintage > 4 years: compared to PD, HD patients had higher LTM (44.3 ±11.7 vs. 38.6 ±7.9; p < 0.05) and lower FAT (34.4 ±11.1 vs. 42.8 ±6.4; p < 0.01). Conclusions Dialysis patients’ body composition depends on dialysis modality and DV. Dialysis vintage < 2 years is associated with better hydration, nutritional state, and survival in PD patients, but longer DV reduces these benefits. Dialysis vintage > 4 years associated with similar hydration and mortality in both PD and HD while body composition was better on HD.

The importance of hypoalbuminemiain peritoneal dialysis patients: Impact of gender

BACKGROUND High mortality in peritoneal dialysis (PD) patients is associated with the presence of nontraditional cardiovascular risk factors, such as malnutrition. However, hypoalbuminemia in patients undergoing PD may have gender-dependent consequences. OBJECTIVES The aim of the study was to evaluate the relationship between hypoalbuminemia, overhydration (OH), inflammation, and cardiovascular risk, depending on gender. MATERIAL AND METHODS The group studied consisted of 54 PD patients: 26 male (mean age: 59 ±19 years) and 28 female (mean age: 52 ±15 years) patients. Serum albumin levels were measured routinely by the hospital central laboratory. The degree of OH was assessed by bioelectrical impedance analysis (BIA). Serum concentrations of C-reactive protein (CRP) and interleukin (IL)-6 were measured as inflammatory markers. Levels of N-terminal prohormone of brain natriuretic peptide (NT-proBNP) and troponin T (TnT) were used to assess cardiovascular risk. RESULTS Median serum albumin concentration was 3.9 g/dL (3.6-4.2 g/dL). Both genders were comparable regarding most parameters except body weight (79 ±16 kg vs 67 ±16 kg; p = 0.009), but no differences were observed in body mass index (BMI) (26.3 ±5.0 kg/m2 vs 26.2 ±5.9 kg/m2; non significant (NS)). There was also no difference in the prevalence of hypoalbuminemia between female and male PD patients (23% vs 21%; NS). In females, low serum albumin concentrations were associated with OH, inflammation and cardiovascular risk, while in males serum albumin levels correlated with the parameters of dialysis and cardiovascular risk. CONCLUSIONS The impact of hypoalbuminemia may be gender-dependent. It seems that hypoalbuminemia is more important for female patients. It is also possible that different mechanisms regulate serum albumin concentration in female and male PD patients.

Higher Serum Hepatocyte Growth Factor Concentration is Associated with Better Preservation of GFR in Hemodialysis Patients

Background/Aims: Hemodialysis induces an intravascular inflammatory reaction which may further deteriorate renal function. We studied changes of serum interleukin 6 (IL6) and hepatocyte growth factor (HGF) concentrations during dialysis sessions, and at 12 month intervals. The synthesis of these cytokines in arterial endothelial cells in the presence of serum obtained from dialyzed patients was studied. Changes of the inflammatory reaction during 12 months of treatment were correlated with GFR. Methods: The study was performed on a group of 30 uremic patients treated with hemodialysis. Serum samples were collected before the start of dialysis, 15 minutes, and 4 hours later, when the session was finished. Serum levels of IL6 and HGF were measured with ELISA, as was the effect of serum samples on the synthesis of these cytokines in arterial endothelial cells. Results: At baseline hemodialysis induced an increase of serum IL6 (+10%) and HGF (+164%) levels at the end of the session. After 12 months of treatment predialysis serum IL 6 level was increased as compared to the beginning of the study (+22%), but no change in serum HGF level was observed. At that time the dialysis-induced rise of serum IL6 level was stronger than at the start (+18%), but the observed effect for HGF was weaker (+116%). An inverse correlation was observed between the dialysis-induced increase of HGF level and decrease of GFR after 12 months of study. The same relation was seen for HGF synthesis in the endothelium, but opposite for IL6 synthesis in the endothelium. Conclusions: We found that a higher HGF serum level during hemodialysis treatment is associated with a slower loss of residual renal function.