Paraskevi Tseke

Vitamin D, the renin-angiotensin system, and insulin resistance.

Insulin resistance is characterized by the systemic impairment of insulin action and is usually the result of aging, obesity, chronic inflammation, or another factor that may contribute to the inhibition of the insulin signaling pathway. Insulin resistance is accompanied by defects in lipid metabolism and blood coagulation, hypertension, obesity, and vascular inflammation in a syndrome called syndrome X or metabolic syndrome. Metabolic syndrome is involved in the development of atherosclerosis with consequent cardiovascular complications including acute myocardial infarction, stroke, and vascular disease. Recent data have shown that vitamin D acts as a negative regulator of the renin gene and that vitamin D deficiency is followed by increased renin-angiotensin II expression. The link between the insulin signaling pathway/insulin resistance and the renin-angiotensin system has been well documented in previous studies. The present review focuses on disorders characterized by a reduction in vitamin D concentration or its receptor function and the development of insulin resistance or metabolic syndrome, and discusses also possible therapeutic interventions.

Epidemiology of acute renal failure in ICUs: a multi-center prospective study.

Background and Aim: Acute kidney injury (AKI) is a common complication in intensive care units (ICUs). However, its incidence and outcome vary in several studies depending on definitions used or even the geographic origin of the study. We aimed to evaluate the epidemiology of AKI in ICUs in Greece. Method: Prospective multicenter study of ICU patients presented with AKI during a 3-month period. Results: One-hundred and seventy patients presented with AKI (16% of total admissions in 23 ICUs). The most common contributing factor to AKI was sepsis (45%). Half of the patients required renal replacement therapy, which was mainly managed by ICU clinicians. Nearly 65% of the AKI patients died, whereas 15% were discharged with renal impairment. Age (RR 1.01, p = 0.046), sepsis (RR 1.62, p = 0.015) and urine output (RR 0.99, p = 0.009) were independently associated with outcome. Conclusion: AKI involves a large number of patients in Greek ICUs and is associated with adverse outcomes.

Correlations of Sialic Acid with Markers of Inflammation, Atherosclerosis and Cardiovascular Events in Hemodialysis Patients

Background: Serum total sialic acid (S-TSA) is associated with atherosclerotic process in general population. The aim of our study was to evaluate possible correlations of S-TSA with markers of inflammation and atherosclerosis in hemodialysis (HD) patients. Methods: We involved 53 asymptomatic, nondiabetic HD patients and 28 healthy controls. Atherosclerosis was evaluated by carotid ultrasonography, estimating intima media wall thickness and wall to lumen ratio bilaterally. To confirm our findings, we performed a 32-month cohort study, during which cardiovascular (CV) events were analyzed in relation to S-TSA concentration. Results: HD patients had higher S-TSA compared to controls (adjusted OR: 1.04, p = 0.026). In HD patients, S-TSA independently correlated with hs-CRP (p < 0.0001), lipoprotein(a) (p = 0.02), intima media wall thickness (p = 0.023) and wall to lumen ratio (p = 0.028). Increased S-TSA concentration was associated with more CV events (p = 0.03). Conclusions: Serum TSA seems to correlate with inflammation, accelerated atherosclerosis and CV events in nondiabetic HD patients, but more studies need to confirm our findings.

Differential associations of renal function with coronary and peripheral atherosclerosis

BACKGROUND The aim of this study was to examine the impact of renal dysfunction on both coronary and peripheral atherosclerosis in patients with coronary artery disease (CAD) without severe renal impairment. METHODS One hundred and eighty-seven consecutive patients referred for elective coronary angiography were enrolled. Mean IMT and the presence of plaques were measured in the carotid and femoral arteries prior to angiography as markers of subclinical peripheral atherosclerosis. The severity of CAD was evaluated by the Gensini score. Glomerular filtration rate (GFR) was estimated by the MDRD formula. RESULTS Significant CAD (>50% stenosis) was identified in 139 patients. GFR independently correlated with the presence and severity of CAD with incremental value over that of IMT. Renal function was significantly but not independently correlated with carotid IMT in CAD patients. Femoral IMT and the presence of plaques did not show any significant correlations with GFR in patients with or without CAD. CONCLUSIONS Renal function is an important predictor of the presence and severity of angiographic CAD in patients without severe renal impairment with incremental value over traditional risk factors for CAD and IMT. The contrasting weak or no associations of GFR with IMT and the presence of plaques suggest that renal dysfunction may exert differential effects on the development of coronary and peripheral atherosclerosis.

Cardiovascular Risk Factors in Non-Diabetic Hemodialysis Patients: A Comparative Study

Patients on hemodialysis (HD) are prone to atherosclerotic cardiovascular complications. In an attempt to determine the significance of several atherosclerotic and thrombogenic parameters as risk factors for atherothrombotic cardiovascular disease (CVD) in these patients, we compared two groups of non-diabetic HD patients matched for age and sex, selected according to the absence (group 1, n = 30) or presence (group 2, n = 30) of symptomatic atherothrombotic vascular disease affecting the coronary, cerebral, or peripheral arteries. Duration of HD, primary renal disease (PRD), presence of hypertension, EPO treatment, and smoking habits were recorded. Serum total cholesterol (TC), triglycerides (TG), HDL-C, LDL-C, TC/HDL-C ratio, lipoprotein(a) (Lp(a)), fibrinogen (FG), plasminogen (PLG), fibronectin (FN), and hematocrit (HCT) were measured pre-HD in a midweek session. The same blood parameters were also assessed in twenty matched clinically healthy subjects (controls). None of the blood parameters differed between groups 1 and 2, except for serum Lp(a) and FN, which were higher in group 2 (p = 0.005 and p = 0.041, respectively). Both groups were not different regarding PRD, duration of HD, and EPO treatment, but the presence of hypertension and smoking habits were more common in group 2 (p = 0.008 and p = 0.045, respectively). Moreover, multiple stepwise logistic regression analysis with Lp(a), FN, hypertension, and smoking showed that the presence of hypertension (p = 0.016) and the Lp(a) (p = 0.027) and FN (p = 0.024) levels, but not smoking, were independent predictors for the presence of atherothrombotic CVD. Our results suggest that hypertension, abnormal lipid particles, and thrombogenic proteins may contribute to the high prevalence of CVD in HD patients.

Studying Survival Studies in PD versus HD: Is There Something More to Know?

Abstract Peritoneal dialysis (PD) has been introduced more than 25 years ago as an alternative to hemodialysis for the treatment of end-stage renal disease. However, after the peak of the number of PD patients, which was noted in the mid-1980s, and despite the fact that in some countries there is a tendency for PD first, the number of incident PD patients in Europe and the United States is constantly decreasing. A large number of studies comparing the effect of these two treatment modalities on patients’ outcomes have yielded conflicting results, which raise confusing messages to nephrologists. Epidemiologic methods, survival analysis models, and interpretation of results are not always clear and understandable for the average nephrologist. This review will focus on the exploration of possible causes of discrepancy among survival studies and it will try to clarify the basic key points of survival analysis in order to make the results as clear as possible.