Evangelia Dounousi

Dyslipidemia in chronic kidney disease: an approach to pathogenesis and treatment.

BACKGROUND/AIMS Cardiovascular disease (CVD) is a major cause of mortality in patients with mild to moderate chronic kidney disease (CKD) and end-stage renal disease (ESRD). Dyslipidemia has been established as a well-known traditional risk factor for CVD in the general population and it is well known that patients with CKD exhibit significant alterations in lipoprotein metabolism. In this review the pathogenesis and treatment of renal dyslipidemia are discussed. METHODS Studies on lipid abnormalities in CKD stages 1-4, in nephrotic syndrome, and in hemodialysis and peritoneal dialysis patients are analyzed, as well as the lipid profile of kidney graft recipients. Also, the results of the effects of epoietin treatment and hypolipidemic drugs in CKD patients are reported. RESULTS Disturbances in lipoprotein metabolism are evident even at the early stages of CKD and usually follow a downhill course that parallels the decline of renal function. However, several intrinsic or exogenous factors can influence the phenotypic expression of these alterations. According to the literature, current evidence suggests that unlike dialysis patients, mild to moderate CKD patients could be benefit from the use of statins. CONCLUSION The use of statins is indicated in patients with mild to moderate CKD, while in subjects with ESRD lipid-lowering therapy should be individualized.

Methodology used in studies reporting chronic kidney disease prevalence: a systematic literature review

Background Many publications report the prevalence of chronic kidney disease (CKD) in the general population. Comparisons across studies are hampered as CKD prevalence estimations are influenced by study population characteristics and laboratory methods. Methods For this systematic review, two researchers independently searched PubMed, MEDLINE and EMBASE to identify all original research articles that were published between 1 January 2003 and 1 November 2014 reporting the prevalence of CKD in the European adult general population. Data on study methodology and reporting of CKD prevalence results were independently extracted by two researchers. Results We identified 82 eligible publications and included 48 publications of individual studies for the data extraction. There was considerable variation in population sample selection. The majority of studies did not report the sampling frame used, and the response ranged from 10 to 87%. With regard to the assessment of kidney function, 67% used a Jaffe assay, whereas 13% used the enzymatic assay for creatinine determination. Isotope dilution mass spectrometry calibration was used in 29%. The CKD-EPI (52%) and MDRD (75%) equations were most often used to estimate glomerular filtration rate (GFR). CKD was defined as estimated GFR (eGFR) <60 mL/min/1.73 m2 in 92% of studies. Urinary markers of CKD were assessed in 60% of the studies. CKD prevalence was reported by sex and age strata in 54 and 50% of the studies, respectively. In publications with a primary objective of reporting CKD prevalence, 39% reported a 95% confidence interval. Conclusions The findings from this systematic review showed considerable variation in methods for sampling the general population and assessment of kidney function across studies reporting CKD prevalence. These results are utilized to provide recommendations to help optimize both the design and the reporting of future CKD prevalence studies, which will enhance comparability of study results.

Mononuclear Leukocyte Apoptosis and Inflammatory Markers in Patients with Chronic Kidney Disease

Background/Aim: Increased apoptosis along with enhanced inflammation has been reported in hemodialysis and pre-dialysis patients. However, there is limited information at which stage during the progression of chronic kidney disease (CKD) the balance between pro- and anti-apoptotic mechanisms is disturbed and inflammatory response is activated. The aim of this study was to investigate possible alterations in apoptotic and inflammatory markers during CKD (stages 1–4) progression and the probable interactions between them. Methods: In a cross-sectional study, 152 steady-state CKD outpatients (83 males, 55%) with mean estimated glomerular filtration rate 46 (29–76) ml/min/1.73 m2 were studied. Apoptosis was assessed in peripheral blood mononuclear cells by estimating Bcl-2 expression, annexin V-propidium iodine staining and serum soluble Fas (sFas) and Fas-ligand. Serum levels of C-reactive protein, tumor necrosis factor-α (TNF-α), interleukin-6 and plasma levels of fibrinogen were measured as markers of inflammation. Results: Bcl-2 expression was found to decrease significantly in both lymphocytes and monocytes from CKD stage 1 to 4. In contrast, the activity of sFas increased significantly and so did the levels of TNF-α and fibrinogen. The majority of these alterations occurred as soon as patients entered stage 3 of CKD. A multivariate regression analysis demonstrated that CKD remained a significant predictor of the aggregate of the assessed markers. Conclusions: Apoptosis appeared to increase across CKD stages 1–4, and this was associated with increased proinflammatory activity.

Inflammation, Endothelial Dysfunction and Increased Left Ventricular Mass in Chronic Kidney Disease (CKD) Patients: A Longitudinal Study

Introduction Within this longitudinal study we investigated the association of inflammation markers C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor-α (TNFα) and endothelial dysfunction markers intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) with left ventricular mass indexed for height2·71 (LVMI) in hypertensive predialysis CKD patients. Material and Methods From 2004 to 2005, 182 incident consecutive adult patients from the outpatient CKD clinics of two hospitals in Greece with CKD and hypertension or using antihypertensive medication, were included. Of these, 107 patients underwent CRP (mg/l) and LVMI (g/height2·71) measurements annually for three years. Results In the longitudinal analyses, using linear mixed modeling, a higher IL-6 (ß = 1.9 (95%ci:0.38;3.5), inflammation score based on CRP, IL-6 and TNF-α (ß = 5.0 (95%ci:0.72; 9.4) and VCAM-1 (ß = 0.01 (95%ci:0.005;0.02) were associated with higher LVMI. These models were adjusted for age, gender and primary renal disease, and for confounders that on top changed the beta with ≥10%, i.e. diuretic use (for IL-6 and inflammation score). Conclusion The results suggest that in predialysis CKD patients, inflammation as well as endothelial dysfunction may play an important role towards the increase in LVMI.

Chronic Kidney Disease and Disproportionally Increased Cardiovascular Damage: Does Oxidative Stress Explain the Burden?

Chronic kidney disease (CKD) patients are among the groups at the highest risk for cardiovascular disease and significantly shortened remaining lifespan. CKD enhances oxidative stress in the organism with ensuing cardiovascular damage. Oxidative stress in uremia is the consequence of higher reactive oxygen species (ROS) production, whereas attenuated clearance of pro-oxidant substances and impaired antioxidant defenses play a complementary role. The pathophysiological mechanism underlying the increased ROS production in CKD is at least partly mediated by upregulation of the intrarenal angiotensin system. Enhanced oxidative stress in the setting of the uremic milieu promotes enzymatic modification of circulating lipids and lipoproteins, protein carbamylation, endothelial dysfunction via disruption of nitric oxide (NO) pathways, and activation of inflammation, thus accelerating atherosclerosis. Left ventricular hypertrophy (LVH) and heart failure are hallmarks of CKD. NADPH oxidase activation, xanthine oxidase, mitochondrial dysfunction, and NO-ROS are the main oxidative pathways leading to LVH and the cardiorenal syndrome. Finally, a subset of antioxidant enzymes, the paraoxonases (PON), deserves special attention due to abundant clinical evidence accumulated regarding reduced serum PON1 activity in CKD as a contributor to the increased burden of cardiovascular disease. Future, meticulously designed studies are needed to assess the effects of antioxidant therapy on patients with CKD.

Intact FGF23 and α‐klotho during acute inflammation/sepsis in CKD patients

High FGF23 and low α‐Klotho levels associate with systemic inflammation and reduced nitric oxide (NO) bioavailability, but the dynamics of this relationship in patients with CKD has not been investigated.

Switch from conventional to every other day hemodialysis: a comparison pilot study.

Fluid and solute fluctuations during the week are the main drawbacks of conventional hemodialysis (cHD) in patients’ outcomes. The aim of our study was to evaluate the influence of every other day hemodialysis (eodHD) on clinical and laboratory parameters and to compare to that of cHD. Eighteen patients on cHD were included in the study. Nine patients (group I) were randomly switched to eodHD, while the rest (group II) remained on their regular cHD. By the end of the study (12 months) we observed a reduction in body weight followed by a parallel reduction in predialysis mean blood pressure by 7 mm Hg in group I (p < 0.05) and the number of antihypertensives. Moreover, a reduction in left ventricular mass and an increment of ejection fraction was observed in group I. Hemoglobin levels remained stable in both groups, but erythropoietin dose was reduced in eodHD group. Dialysis delivered dose (dpKt/V) was higher and urea rebound phenomenon was less in group I. Finally, an improvement in uremia related and postdialysis symptoms was observed in the same group of patients. Our results showed that eodHD improved patients’ clinical and biochemical status and therefore might have advantages in patients’ outcomes compared with cHD.

Oxidative Stress in Hemodialysis Patients: A Review of the Literature

Hemodialysis (HD) patients are at high risk for all-cause mortality and cardiovascular events. In addition to traditional risk factors, excessive oxidative stress (OS) and chronic inflammation emerge as novel and major contributors to accelerated atherosclerosis and elevated mortality. OS is defined as the imbalance between antioxidant defense mechanisms and oxidant products, the latter overwhelming the former. OS appears in early stages of chronic kidney disease (CKD), advances along with worsening of renal failure, and is further exacerbated by the HD process per se. HD patients manifest excessive OS status due to retention of a plethora of toxins, subsidized under uremia, nutrition lacking antioxidants and turn-over of antioxidants, loss of antioxidants during renal replacement therapy, and leukocyte activation that leads to accumulation of oxidative products. Duration of dialysis therapy, iron infusion, anemia, presence of central venous catheter, and bioincompatible dialyzers are several factors triggering the development of OS. Antioxidant supplementation may take an overall protective role, even at early stages of CKD, to halt the deterioration of kidney function and antagonize systemic inflammation. Unfortunately, clinical studies have not yielded unequivocal positive outcomes when antioxidants have been administered to hemodialysis patients, likely due to their heterogeneous clinical conditions and underlying risk profile.

PCSK9 in chronic kidney disease

PurposeChronic kidney disease (CKD) is accompanied by a number of secondary metabolic dysregulations, such as lipid abnormalities, presenting with unique characteristics. Proprotein convertase subtilisin/kexin 9 (PCSK9) inhibitors have been introduced as the new era in the management of dyslipidemia with promising results in groups with refractory lipid abnormalities. Increasing number of studies investigate the possible association of PCSK9 levels with kidney function, especially with nephrotic range proteinuria, as well as its role as a prognostic cardiovascular risk marker in CKD. In this review, we discuss the existing evidence for PCSK9 levels in patient groups with nephrotic syndrome, non-dialysis CKD, end-stage renal disease and kidney transplantation.MethodsOnline research was conducted in MEDLINE database to identify articles investigating PCSK9 in all different aspects of CKD. References from relevant studies were screened for supplementary articles.ResultsFour cross-sectional studies, one secondary analysis, one publication from two independent cohort studies and one multicentre prospective cohort study assessed PCSK9 plasma levels in different subgroups of CKD patients. PCSK9 levels increase in nephrotic syndrome and have a positive correlation with proteinuria. In CKD patients, no correlation was found between PCSK9 levels and estimated GFR. Peritoneal dialysis patients have higher PCSK9 levels compared with hemodialysis and renal transplant patients as well as general population.ConclusionAccumulative evidence focuses on the possible association of PCSK9 levels with kidney function. No data are available for the administration of PCSK9 inhibitors in CKD patients. Further research will optimize knowledge on the role of PCSK9 levels and PCSK9 inhibitors in CKD.

Metabolic acidosis during parenteral nutrition: Pathophysiological mechanisms

Total parenteral nutrition (TPN) is associated with metabolic complications including metabolic acidosis (MA), one of the main disorders of acid-base balance. The main causes involved in the appearance of MA during TPN administration are the metabolism of cationic amino acids and amino acids containing sulfuric acid (exogenous addition), the titratable acidity of the infused parenteral solution, the addition of acidificant agents (hydrochloric acid, acetic acid), thiamine deficiency, disruption of carbohydrate and lipid metabolic pathways and D-fructose administration. Moreover, hypophosphatemia that appears during TPN therapy contributes significantly to the maintenance of MA. This review describes in a comprehensive way the pathophysiological mechanisms involved in the appearance of MA induced by intravenous administration of TPN products most commonly used in critically ill-patients.