The effect of the initiation of renal replacement therapy on lipid profile and oxidative stress during the first 6 months of treatment

Increased Levels of sRAGE in Diabetic CKD-G5D Patients: A Potential Protective Mechanism against AGE-Related Upregulation of Fibroblast Growth Factor 23 and Inflammation

Advanced glycation end products (AGEs) may induce cardiac remodeling in kidney disease by promoting fibroblast growth factor 23 (FGF-23) expression. Since AGEs are increased in diabetes mellitus (DM), our first aim was to evaluate the existence of any potential association between AGEs, FGF-23, inflammation, and increased cardiovascular risk in DM patients on dialysis (CKD-G5D). Secondarily, we explored the potential role of the soluble receptor for AGEs (sRAGE) as a marker of heart failure. Levels of glycated albumin (GA), sRAGE, c-terminal FGF-23 (cFGF-23), brain natriuretic peptide (BNP), and inflammatory mediators were compared between DM and non-DM CKD-G5D patients. The levels of sRAGE, cFGF-23, BNP, and proinflammatory markers were over the ranges of normality in both DM and non-DM groups. Only GA and sRAGE levels were increased in DM compared to non-DM patients. Plasma levels of sRAGE and CRP were the only independent predictors of BNP concentration. In conclusion, in DM CKD-G5D patients, sRAGE appeared to be a marker of cardiac remodeling. Indeed, its increase could be a potential protective mechanism against the increased risk of cardiovascular complications related to AGEs and inflammation. The causal relationship between sRAGE and cardiovascular risk in these patients needs to be further confirmed by mechanistic studies.

Targeting cannabinoid signaling for peritoneal dialysis-induced oxidative stress and fibrosis

Long-term exposure to bioincompatible peritoneal dialysis (PD) solutions frequently results in peritoneal fibrosis and ultrafiltration failure, which limits the life-long use of and leads to the cessation of PD therapy. Therefore, it is important to elucidate the pathogenesis of peritoneal fibrosis in order to design therapeutic strategies to prevent its occurrence. Peritoneal fibrosis is associated with a chronic inflammatory status as well as an elevated oxidative stress (OS) status. Beyond uremia per se, OS also results from chronic exposure to high glucose load, glucose degradation products, advanced glycation end products, and hypertonic stress. Therapy targeting the cannabinoid (CB) signaling pathway has been reported in several chronic inflammatory diseases with elevated OS. We recently reported that the intra-peritoneal administration of CB receptor ligands, including CB₁ receptor antagonists and CB₂ receptor agonists, ameliorated dialysis-related peritoneal fibrosis. As targeting the CB signaling pathway has been reported to be beneficial in attenuating the processes of several chronic inflammatory diseases, we reviewed the interaction among the cannabinoid system, inflammation, and OS, through which clinicians ultimately aim to prolong the peritoneal survival of PD patients.

Protein oxidative stress and dyslipidemia in dialysis patients

Our aim was to investigate and determine the associations between oxidative stress (OS), dyslipidemia and inflammation in patients treated with continuous ambulatory peritoneal dialysis (CAPD) and hemodialysis (HD) using observational cross-sectional study. Twenty patients in CAPD and 48 in HD for at least 8 weeks and aged ≥18 years were included in the study. Individuals with malignant or acute inflammatory disease were excluded. A control group of 17 healthy individuals was also recruited. The biochemical parameter evaluations were analyzed using colorimetric kits for albumin, serum glucose, total cholesterol (TC) and lipid fractions. To determine the inflammatory status, CRP, IL-6 and TNF-α were analyzed by automated chemiluminescence kits. Plasma advanced oxidation protein products (AOPP) were determined by spectrophotometry. Mean AOPP levels were significantly higher for the HD group compared to the control, and there was no difference in AOPP concentrations between the control and CAPD groups. Dialysis patients had levels of inflammatory parameters higher than controls, and showed a high prevalence of patients with dyslipidemia, especially in CAPD. In the HD group, AOPP was positively correlated with triglycerides (TG) and inversely associated with HDL. Also the HD group was observed to have negative associations between TNF-α and HDL, LDL and TC. In the CAPD group, CRP was inversely correlated with HDL. Hemodialysis patients had increased protein OS and associations of inflammation and dyslipidemia were also observed in these dialysis groups. A more detailed characterization of the relations between oxidative stress and other more traditional risk factors has therapeutic importance, since cardiovascular diseases are the leading cause of death among dialysis patients.

The effects of 1-year treatment with a haemodiafiltration with on-line regeneration of ultrafiltrate (HFR) dialysis on biomarkers of oxidative stress in patients with chronic renal failure

In the last few years haemodiafiltration with on-line regeneration of ultrafiltrate (HFR) has been shown to have a positive impact on inflammation and oxidative stress biomarkers, but its effect on antioxidant levels and on oxidative damage to biomolecules in the long-term is still unknown. This is a randomised clinical study over 12 months involving 40 patients on haemodialysis, comparing the effect of HFR (n=25) dialysis with haemodialysis with polysulfone (HD-PS, n=15) on oxidative stress. Total antioxidant capacity, enzymatic antioxidant [superoxide dismutase (SOD), catalase and glutathione peroxidase], non-enzymatic (GSH) and biomarkers of oxidative stress (TBARs, carbonyl groups and 8-OH-dG) were evaluated. The antioxidant activity decreased in the lymphocytes of patients dialysed with HFR, with a significant decrease in the enzyme SOD. In the oxidative stress biomarkers, an increase was seen in the levels of 8-OH-dG in patients on HD-PS dialysis but not in those treated with HFR. Throughout the year the changes in antioxidant levels and biomarkers of oxidative damage in patients dialysed with HFR were generally more modest and fluctuated less than those dialysed with HD-PS. Our study indicates that, in general, long-term dialysis with HFR does not modified antioxidant parameters or increases the oxidative damage to biomolecules. The HFR showed to be a biocompatible technique for long-term dialysis.

The impact of haemodialysis-associated variables on lipid profile in Egyptian haemodialysis population

INTRODUCTION

Haemodialysis (HD) patients appear to have particular susceptibility for cardiovascular (CV) diseases with lipid abnormalities among its significant contributors. However, there is controversy concerning the combined effect on lipid constituents during HD of the three commonly used variables; the type of heparin, dialysis membrane and the constituent of dialysate buffer bases. Consequently, this controlled prospective study was thought of.

PATIENTS

Randomly 63 patients were assigned from Urology and Nephrology haemodialysis (HD) unit, Mansoura, Egypt for the planned study. Their mean age was 45.79 +/- 13.11 years. Fourteen patients with end-stage renal disease (ESRD) served as control group for the remaining 49 HD patients. They were subdivided according to the HD duration (< and > 1 year), anticoagulant used (unfractionated [UFH] and low-molecular weight heparin [LMWH, Enoxaparin), membrane type (Hemophane [HP] and polysulfone [PS] membrane) and dialysate buffer bases (bicarbonate versus acetate based).

METHODS

Determining the fasting lipid value of total cholesterol (TC) and triglycerides (TG) as well as lipoproteins including low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and lipoprotein (a) [Lp (a)] was completed.

RESULTS

Bicarbonate dialysate was associated with significantly lower TG (134.7 +/- 11 mg/dl vs. 153 +/- 14 mg/dl, p = 0.004), higher HDL-C (33.1 +/- 3 vs. 28.3 +/- 2, p = 0.0002) and subsequently better atherosclerosis risk ratio [TC/HDL-C (ARR)] (6.02 +/- 0.09 vs. 5.3 +/- 0.9, p = 0.001) despite its insignificant effect on TC and LDL-C. However, logarithm (log) Lp (a) level was significantly higher (1.92 +/- 0.05 vs. 1.82 +/- 0.04 p = 0.001) in comparison with acetate dialysate. Membrane type was not influential in those dialyzed for < 1 year before intervention while after a year of HD, PS (n = 11) compared to HP filters (n = 11) significantly lowered TC (151.7 +/- 16 vs. 172.6 +/- 12, p = 0.003), TG (127.8 +/- 15 vs. 155.7 +/- 15, p = 0.004), LDL-C (122.1 +/- 5 vs. 130.6 +/- 7, p = 0.006) levels as well as ARR (5.9 +/- 0.5 vs. 5.4 +/- 0.3, p = 0.02). Likewise was the reduction in log Lp (a) (1.9 +/- 0.03 vs. 1.8 +/- 0.04, p = 0.002) with insignificant effect on HDL-C. After 6 months, Enoxaparin caused significant improvement of TC (0.0004), TG (p = 0.018), LDL-C (p = 0.006), HDL-C (0.041) and Lp (a) (0.047) compared to UFH. Patients who continued on Enoxaparin for 3 more months displayed an even better attenuation in most of lipid parameters whilst continuation of UFH was insignificant. Switching few patients (n = 4) from UFH to LMWH for 3 months resulted in significant lowering of TC (153 +/- 7 vs. 177.7 +/- 3, p = 0.01), TG (127.5 +/- 5 vs. 137.3 +/- 4, p = 0.03) and LDL-C (124.7 +/- 5 vs. 127.5 +/- 5, p = 0.005). However, switching equal number of patients from LMWH to UFH caused no significant change.

CONCLUSION

Dyslipidaemia in Egyptian haemodialysis patients was improved when bicarbonate-based haemodialysis, the use of polysulfone membrane, and more so when the low-molecular weight heparin Enoxaparin were used.