Sabrina Paoletti

Anaemia and resistance to erythropoiesis-stimulating agents as prognostic factors in haemodialysis patients: results from the RISCAVID study

BACKGROUND Resistance to erythropoiesis-stimulating agents (ESAs) is often associated with chronic inflammation. Here, we investigated how anaemia, ESA resistance and the plasma levels of biological markers of inflammation could influence all-cause and cardiovascular disease morbidity and mortality. METHODS Seven hundred and fifty-three haemodialysis (HD) patients (mean age 66 ± 14.2 years, mean dialytic age 70 ± 77 months and diabetes 18.8%) were enrolled and followed-up for 36 months. Demographic, clinical and laboratory data, co-morbidity conditions, administered drugs, all-cause mortality and fatal/non-fatal cardiovascular (CV) events were recorded. We measured ESA resistance index, C-reactive protein (CRP) and interleukin-6 (IL-6). RESULTS Six hundred and fifty-one patients (86.4%) received ESAs. Patients with haemoglobin level <11 g/dL (n = 225) showed increased risk of CV [relative risk (RR) 1.415, 95% confidence interval (CI) 1.046-1.914] and overall mortality (RR 1.897, 95% CI 1.423-2.530) versus patients with haemoglobin levels >11 g/dL. ESA resistance values categorized into quartiles (Quartile I <5.6, Quartile II 5.7-9.6, Quartile III 9.7-15.4 and Quartile IV >15.4) correlated with all-cause mortality and fatal/non-fatal CV events (RR 1.97, 95% CI 1.392-2.786; RR 1.619, 95% CI 1.123-2.332, respectively). Furthermore, albumin was significantly reduced versus reference patients and correlated with all-cause mortality and CV events; CRP levels were higher in hyporesponders (Quartile IV) (P < 0.001) and predicted all-cause mortality and CV events. IL-6 but not CRP was a strong predictor of ESA resistance. CONCLUSIONS ESA responsiveness can be considered a strong prognostic factor in HD patients and seems to be tightly related to protein-energy wasting and inflammation.

A Vitamin E-Coated Polysulfone Membrane Reduces Serum Levels of Inflammatory Markers and Resistance to Erythropoietin-Stimulating Agents in Hemodialysis Patients: Results of a Randomized Cross-Over Multicenter Trial

Background: Oxidative stress is prevalent in dialysis patients and has been implicated in the pathogenesis of cardiovascular disease and anemia. Vitamin E is a fat-soluble antioxidant that plays a central role in reducing lipid peroxidation and inhibiting the generation of reactive oxygen species. The aim of this cross-over randomized study was to compare the effects of a vitamin E-coated polysulfone (Vit E PS) membrane and a non-vitamin E-coated polysulfone (PS) membrane on inflammatory markers and resistance to erythropoietin-stimulating agents (ESAs). Methods: After a 1-month run-in period of standard bicarbonate dialysis with a synthetic membrane, 62 patients of both genders, and older than 18 years, dialysis vintage 48 ± 27 months, BMI 22 ± 3 (from 13 different dialysis units) were randomized (A-B or B-A) in a cross-over design to Vit E PS (treatment A) and to PS (treatment B) both for 6 months. C-reactive protein (CRP) and interleukin-6 (IL-6) concentrations were determined by a sandwich enzyme immunoassay at baseline and every 2 months; red blood cell count, ESA dose and ESA resistance index (ERI) were assessed monthly. Results: Hemoglobin (Hb) levels significantly increased in the Vit E PS group from 11.1 ± 0.6 g/dl at baseline to 11.5 ± 0.7 at 6 months (p < 0.001) and remained unchanged in the PS group. Although ESA dosage remained stable during the observation periods in both groups, ERI was significantly reduced in the Vit E PS group from 10.3 ± 2.2 IU-dl/kg/g Hb week at baseline to 9.2 ± 1.7 at 6 months (p < 0.001). No significant variation of ERI was observed in the PS group. A significant reduction in plasma CRP and IL-6 levels was observed in the Vit E PS group: CRP from 6.7 ± 4.8 to 4.8 ± 2.2 mg/l (p < 0.001) and IL-6 from 12.1 ± 1.4 to 7.5 ± 0.4 pg/ml (p < 0.05). In the PS group, CRP varied from 6.2 ± 4.0 to 6.4 ± 3.7, and IL-6 from 10.6 ± 2.1 to 9.6 ± 3.5 (p = n.s.). Conclusions: Treatment with Vit E PS membranes seems to lead to a reduction in ESA dosage in HD patients; in addition, a low chronic inflammatory response may contribute to a sparing effect on exogenous ESA requirements.

Anti-Inflammatory Effect of White Wine in CKD Patients and Healthy Volunteers

Background: Mediterranean-style diet has been considered for its important beneficial effects on the progression of CV disease. Wine is an important component of the Mediterranean diet, and moderate wine drinkers have lower mortality rates than nondrinkers and heavy drinkers in epidemiologic studies. The beneficial effects of red wine are thought to be dependent on the polyphenol compounds such as resveratrol that exhibit potent antioxidant activity. However, white wine, although lacking polyphenols, contains simple phenols, such as tyrosol (Tyr) and hydroxytyrosol (OH-Tyr), characteristic also of extra-virgin olive oil, which may share similar antioxidant and inflammatory properties. Patients and Methods: The effect of white wine and extra-virgin olive oil on inflammatory markers was evaluated in 10 healthy volunteers and in 10 patients with CKD (chronic kidney disease) K-DOQI stage III-IV in a prospective, single blind, randomized, cross-over trial. After two weeks of wash-out from alcoholic beverages, subjects were randomized to a cross-over design A-B or B-A of a 2-week treatment with white wine (4 ml/kg body weight, 0.48 g/kg of alcohol 12%, corresponding to 2-3 glasses/daily) and extra-virgin olive oil (treatment A) or extra-virgin olive oil alone (treatment B). The two study periods were separated by a two-week wash-out period. At baseline and at the end of each treatment, plasma levels of inflammatory markers C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and interleukin-8 (IL-8) concentration were determined. Urinary levels of Tyr, OH-Tyr, and their metabolites were measured at the same time. Results: During combined consumption of white wine and extra-virgin olive oil (treatment A), plasma levels of CRP and IL-6 decreased from 4.1 ± 1.8 to 2.4 ± 1.9 mg/l (p < 0.05) and from 5.3 ± 3.2 to 3.4 ± 2.3 mg/l (p < 0.05) in CKD patients. CRP decreased from 2.6 ± 1.2 to 1.9 ± 0.9 mg/l (p < 0.05), and IL-6 decreased from 2.2 ± 1.8 to 1.7 ± 1.3 mg/l (p = ns) in healthy volunteers. No significant variation versus baseline was observed during treatment B. A significant increase in urinary Tyr and OH-Tyr was observed during treatment A (white wine and extra-virgin olive oil). Conclusions: Plasma markers of chronic inflammation were significantly reduced in CKD patients during the combined consumption of white wine and olive oil, suggesting a possible anti-inflammatory effect of this nutritional intervention.

Biomarkers of Chronic Inflammatory State in Uremia and Cardiovascular Disease

Cardiovascular disease is the leading cause of death in the general population; traditional risk factors seem inadequate to explain completely the remarkable prevalence of cardiovascular mortality and morbidity observed in the uremic population. A role for chronic inflammation has been well established in the development of atherosclerotic disease, and, on the basis of these observations, atherosclerosis might be considered an inflammatory disease. Inflammation has been implicated in the etiology of coronary artery disease in the general population, and traditional inflammatory biomarkers such as C-reactive protein (CRP) and interleukin-6 (IL-6) have been shown to predict cardiovascular events in both symptomatic and asymptomatic individuals as well as those in the uremic population. Later on, new nontraditional markers were related to the risk of cardiovascular morbidity and mortality in general and in uremic population. As a consequence of the expanding research base and availability of assays, the number of inflammatory marker tests ordered by clinicians for cardiovascular disease (CVD) risk prediction has grown rapidly and several commercial assays have become available. So, up to now we can consider that several new nontraditional markers as CD40-CD40 ligand system and pentraxin-3 seem to be significant features of cardiovascular disease in general and in ESRD population.

Inflammatory Pattern in Hemodiafiltration

Chronic inflammation may play an important role in early morbidity and mortality in hemodialysis (HD) patients. Interleukin-6 (IL-6) production is enhanced in long-term HD patients and this activated phase response has been shown to be a predictor of cardiovascular disease in the uremic syndrome as well as in the general population. Furthermore, IL-6 and C-reactive protein (CRP) have been negatively related to low serum albumin levels (MIA syndrome). Several studies have attempted to address the question as to whether the type of the dialysis membrane, the quality of the dialysate, and the dialysis technique may be responsible for the induction of a chronic inflammatory state. Recently, the Dialysis Outcomes and Practice Patterns Study (DOPPS) has shown that high-efficiency hemodiafiltration (HDF)- treated patients had a better survival than HD-treated patients accounting for sex, dialysis dose, co-morbid condition and country specificities. Here we report data from the RISCAVID study, an observational and prospective trial including the whole chronic HD population in the north-west part of Tuscany (1,235 million people). The aim of the study was to elucidate the relevance of traditional and non-traditional risk factors on mortality and morbidity in HD patients as well as the impact of different HD modalities. Data at 30 months from this study showed the synergic effect of CRP and pro-inflammatory cytokines as the strong predictors of overall and cardiovascular mortality. HDF was associated to an improved cumulative survival independently of dialysis dose.

Soluble CD40 ligand is predictive of combined cardiovascular morbidity and mortality in patients on haemodialysis at a relatively short-term follow-up

BACKGROUND We tested the hypothesis that soluble CD40 ligand (sCD40L), a biomarker of proatherogenic inflammation, may be predictive of cardiovascular (CV) events in a subgroup of patients from the RISCAVID study, an observational and prospective study in patients on haemodialysis (HD). METHODS Plasma sCD40L levels were assessed at the time of the enrollment in 300 HD patients (mean age: 65 ± 15 years), recruited in five different centres. During a follow-up of 24 months, overall mortality, CV mortality and CV major nonfatal events (acute myocardial infarction, congestive heart failure and stroke) were registered. Cox proportional hazards regression assessed adjusted differences in CV morbidity and mortality risk. RESULTS Stratifying patients according to plasma sCD40L levels in those with levels lower or equal to (sCD40L-) and greater than (sCD40L+) the median value of 7.6 ng/mL, no significant difference was observed at baseline between the two groups in age, gender, blood pressure values and previous CV events. At 24-month follow-up, a significant (P < 0.01) lower incidence of the combined end point of CV morbidity and mortality was observed in the sCD40L- group (29%) as compared to the sCD40L+ group (36%). In the multivariate Cox proportional hazards regression model, the presence of sCD40L above the median value is associated with a significant increase in the risk of CV morbidity and mortality (hazard ratio: 1.61, 95% confidence interval 1.03-3.11). CONCLUSIONS These observational results support the prognostic value of sCD40L in end-stage renal disease, thus providing a useful tool to better stratify CV prognosis in these patients.

Impact of Dialysis Technique on Renal Anemia

Cardiovascular disease is a significant complication in chronic kidney disease (CKD) and a major cause of death in dialysis patients. Clinical studies have shown that anemia is associated with reduced survival in patients undergoing chronic hemodialysis. Furthermore, an association between anemia and adverse cardiovascular outcomes has also been observed in patients with earlier stages of CKD not yet requiring dialysis. Although this fact still remains controversial, high-efficiency on-line hemodiafiltration (HDF) has been shown to improve anemia and to reduce the need for erythropoietin-stimulating agents in hemodialysis (HD) patients. This positive effect has been attributed to the fact that the convective methods might remove some protein-bound erythropoietic inhibitor substances. Moreover, in HD patients, renal anemia is linked to the inflammatory state of uremic syndrome. It is also worth nothing that the improvement in anemia is associated with a reduced inflammatory state in patients undergoing on-line HDF. Here, we have reviewed the current knowledge of the effect of dialysis technique on renal anemia.