Lipid parameters including Lp(a) in hemodialysis patients

Lipid Parameters Including Lipoprotein (A) in Patients Undergoing CAPD and Hemodialysis

Objective

Oyslipidemia possibly contributes to the vascular complications commonly afflicting uremic patients. Lipoprotein (a) [Lp(a)] has been identified as an independent risk factor for atherosclerotic vascular dis ease. The aim of our study was to compare lipidparameters, including Lp(a), between hemodialysis (HO) and continuous ambulatory peritoneal dialysis (CAPO) patients.

Design

A cross-sectional study.

Setting

University Medical Center.

Participants

Forty CAPO and 40 HO patients carefully matched for age, sex, body mass index (BMI), smoking habits, and duration of dialysis were studied. A group of 40 healthy individuals matched for age, sex, BMI, and smoking habits was used as control.

Interventions

None.

Main Outcome Measures

Serum lipid parameters and atherogenic risk ratios were the main outcome measures.

Results

Both groups of dialysis patients had increased serum triglycerides and decreased levels of Apo AI and HOL cholesterol compared to controls. Moreover, the risk ratios total cholesterol/HOL cholesterol and LOL cholesterol/HOL cholesterol were significantly higher, and the ratio ApoA1/ApoB was significantly lower in both groups of patients in comparison to the normal subjects. Both groups of dialysis patients exhibited decreased ratios of LOL cholesterol/ApoB and HOL cholesterol/ApoAI, suggesting the presence of compositional lipoprotein changes. CAPO patients had a more atherogenic lipid profile compared to HO patients, since they exhibited higher levels of total and LOL cholesterol, of ApoB as well as of the ratios total cholesterol/HOL cholesterol and LOL cholesterol/ HOL cholesterol, and lower levels of the ratio ApoA1/ApoB compared to HO patients. Both groups of dialysis patients had increased serum Lp(a) levels. Even though CAPO patients had higher serum Lp(a) levels than HO patients, the differences between these two groups were only marginally statistically significant (p = 0.056 by Mann-Whitney U-test). Uremic dyslipidemia was positively correlated with serum albumin levels in both groups of patients.

Conclusion

CAPO patients exhibit a more atherogenic lipid profile than that of HO patients. The marked disturbances in Lp(a) levels may further increase the vascular risk in both groups of patients.

Profil lipidique dans l’insuffisance rénale chronique au stade d’hémodialyse

INTRODUCTION

The chronic kidney failure is a source of dyslipidemia and accelerated atherosclerosis. No changes in the lipoprotein profile could be reversed by dialysis.

OBJECTIVE

Our aim was to study the lipid disturbances characteristics in end stage renal disease in order to assess their theorical atherogenic potential.

SUBJECTS AND METHODS

The patient population consisted of 36 patients on maintenance haemodialysis. Matched control subjects were recruited among apparently healthy normolipidemic Tunisians. Total cholesterol, triglycerides, high-density-lipoprotein cholesterol, low-density-lipoprotein cholesterol, apolipoprotein AI and apolipoprotein B concentrations were measured.

RESULTS

The triglycerides levels were significantly higher in patient group, unlike the high-density-lipoprotein cholesterol and apolipoprotein AI levels that were significantly reduced. We saw no increase in the levels of low-density-lipoprotein cholesterol and apolipoprotein B. The low-density-lipoprotein cholesterol/high-density-lipoprotein cholesterol ratio result wasn't helpful in the evaluation of the atherogenic risk.

CONCLUSION

We confirm the quantitative lipid disorders associated with maintenance haemodialysis. The assessment of cardiovascular risk on the basis of these disorders seems difficult.

Management of selected lipid abnormalities: hypertriglyceridemia, isolated low HDL-cholesterol, lipoprotein(a), and lipid abnormalities in renal diseases and following solid organ transplantation

Although the focus in treating lipid disorders is on reducing LDL-C levels, additional lipid-related independent risk factors, such as TG, HDL-C, and Lp(a) levels, should be used clinically to assess cardiovascular risk. Decisions to initiate drug therapy for LDL-C reduction may be influenced by levels of these other lipoprotein fractions. Data supporting intervention to modify these factors are less abundant than for LDL-C reduction, but in certain circumstances. drug therapy targeted at TGs or HDL-C may be appropriate. Patients who have nephrotic syndrome and end-stage renal disease are at particularly high risk for the development of CVD and should be treated aggressively for their lipid disorders. Finally, solid organ transplant recipients are almost always hyperlipidemic and appropriate therapy could reduce cardiovascular events.

Are lipid values and BMI related to hospitalizations in the hemodialysis population?

OBJECTIVE

To examine the relationship between lipid values and BMI (body mass index) on hospitalizations in hemodialysis (HD) patients.

DESIGN

Retrospective (2-year) study.

SETTING

Outpatient dialysis center in a large metropolitan city.

PATIENTS

This study used 158 HD patients stratified on the basis of ethnicity (non-Black and Black) and diabetic status (nondiabetic and diabetic).

INTERVENTION

Subjects were observed for 2 years. Body weight, BMI, lipid parameters, and hospitalization duration were determined 8 times (3-month intervals).

MAIN OUTCOME MEASURES

Body weight, BMI, lipid parameters (serum triglyceride concentration, serum total cholesterol, high-density lipoprotein [HDL]-, low-density lipoprotein [LDL]-, very low-density lipoprotein [VLDL]- cholesterol concentrations, serum Apo-protein A1 [Apo-A1] concentration, and serum Apo-protein B [Apo-B] concentration), and morbidity data were recorded.

RESULTS

Hemodialysis subjects were hospitalized 2.3 +/- 1.6 times over the 2-year experimental period. Length of hospital stay averaged 6.6 +/- 0.5 days/hospitalization. Length of hospital stay was inversely related to HDL concentration (r = -0.21, P <.05, n = 89), but not significantly related to BMI in HD subjects. BMI was positively associated with LDL concentration (r = +0.28, P <.01, n = 97). Cholesterol concentration was directly associated with LDL concentration (r = +0.52, P <.01, n = 138), VLDL concentration (r = +0.47, P <.01, n = 139), and triglyceride concentration (r = +0.54, P <.01, n = 155). Mean concentration of HDL-cholesterol was inversely related serum triglyceride concentration (r = -0.43, P <.01, n = 140). Although Apo-A1 concentration was directly associated with HDL level (r = +0.39, P <.01, n = 139), Apo-B was inversely related to HDL level (r = -0.37, P <.01, n = 138) and directly related to cholesterol concentration (r = +0.71, P <.01, n = 138), VLDL concentration (r = +0.87, P <.01, n = 138), and triglyceride concentration (r = +0.81, P <.01, n = 138).

CONCLUSION

Cardiac disease remains the primary cause of morbidity and mortality in HD patients, and results of the present study suggest that dyslipidemias present in the HD population negatively impact cardiovascular profiles which, in turn, influence the frequency/duration of hospitalizations. Among all lipid parameters analyzed in the present study, increased LDL and decreased HDL concentrations were more strongly related to length of hospital stay than was BMI.

Management of selected lipid abnormalities. Hypertriglyceridemia, low HDL cholesterol, lipoprotein(a), in thyroid and renal diseases, and post-transplantation

Although the focus in treating lipid disorders is on reducing LDL cholesterol levels, triglycerides, HDL cholesterol, and Lp(a) are all independent risk factors that can be used clinically to assess cardiovascular risk. Decisions to initiate drug therapy for LDL cholesterol reduction may be influenced by levels of these other lipoprotein fractions. Data supporting intervention to modify these factors is less abundant than for LDL cholesterol reduction, but in certain circumstances drug therapy targeted at triglycerides or HDL cholesterol may be appropriate. Patients with nephrotic syndrome and end-stage renal disease are at particularly high risk for the development of cardiovascular disease and should be treated aggressively for lipid disorders. Finally, solid organ transplant recipients are almost always hyperlipidemic, and appropriate therapy could reduce cardiovascular events.

Plasma and Lp(a)-associated PAF-acetylhydrolase activity in uremic patients undergoing different dialysis procedures

Plasma and Lp(a)-associated PAF-acetylhydrolase activity in uremic patients undergoing different dialysis procedures.

BACKGROUND

Platelet-activating factor (PAF) is a potent inflammatory mediator associated with several physiopathological conditions, including renal diseases. PAF is degraded to the inactive metabolite lyso-PAF by PAF-acetylhydrolase (PAF-AH), which is considered as a potent anti-inflammatory and anti-atherogenic enzyme associated with lipoproteins. In this study, we evaluated the plasma- and lipoprotein(a) [Lp(a)]-associated PAF-AH activity in relationship to plasma lipid parameters and Lp(a) isoform size in patients with mild/moderate chronic renal failure (CRF), as well as in hemodialysis (HD) and chronic ambulatory peritoneal dialysis (CAPD) patients.

METHODS

We studied 74 patients undergoing maintenance HD, 44 patients undergoing CAPD, 56 patients with mild/moderate CRF, and 98 healthy subjects whose lipid profile, as well as plasma and high-density lipoprotein (HDL)-associated PAF-AH activity, was determined. Moreover, the effect of Lp(a) plasma levels on the distribution of PAF-AH among plasma lipoproteins, as well as the specific activity and kinetic properties of PAF-AH on two different Lp(a) isoforms, was measured in each studied group.

RESULTS

The plasma PAF-AH activity in all studied groups was significantly higher than in controls, and the increase was more profound in CAPD patients. The HDL-associated PAF-AH activity, expressed per milliliter of plasma, was similar among all studied groups; however, when it was expressed as either per milligrams of HDL cholesterol or per milligrams of plasma apolipoprotein (apo) AI, the PAF-AH activity was significantly higher in all patient groups compared with controls. All patient groups had significantly elevated plasma Lp(a) levels, which altered the distribution of PAF-AH among the plasma lipoproteins compared with that observed in subjects with very low plasma Lp(a) levels (<8 mg/dl). Additionally, in each studied group, the specific activity as well as the apparent Km and Vmax values of the 19K4 apo(a) isoform were significantly higher (P < 0.01) compared with the values of the 23K4 isoform. However, the specific activity, as well as the Km and Vmax values on either the 19K4 apo(a) isoform or the 23K4 isoform, was significantly higher in CAPD patients compared with the other three groups.

CONCLUSIONS

Plasma PAF-AH activity is increased in uremic patients. This elevation is more profound in CAPD patients, who also exhibit a more atherogenic lipid profile and more pronounced alterations in the specific activity and the kinetic constants of Lp(a)-associated PAF-AH.

Apolipoprotein(a) phenotypes and lipoprotein(a) concentrations in patients with renal failure

Patients with renal failure have an increased incidence of atherosclerotic disease. Numerous studies have shown that these patients show increased serum lipoprotein(a) [Lp(a)] concentrations compared with the control population. However, variable alleles at the apolipoprotein(a) [apo(a)] gene locus determine to a large extent the Lp(a) concentration in the general population. We therefore undertook the present study to evaluate apo(a) phenotypes and Lp(a) serum concentrations in a large number of patients with renal disease. Seventy-nine patients treated by hemodialysis (HD), 47 patients treated by continuous ambulatory peritoneal dialysis (CAPD), 68 patients with mild/moderate chronic renal failure (CRF) and serum creatinine levels of 1.8 to 8 mg/dL, and 73 healthy controls were studied. All patients showed significantly elevated median serum Lp(a) concentrations in comparison with controls: HD patients, 15.7 mg/dL (P < 0.01); CAPD patients, 20 mg/dL (P < 0. 005); CRF patients, 15.1 mg/dL (P < 0.01) versus controls, 7 mg/dL. The greater Lp(a) values in all groups were not explained by differences in isoform frequencies, whereas their increase was apo(a)-type specific. Thus, patients in all groups with high-molecular-weight (HMW) apo(a) isoforms showed a significant elevation of Lp(a) levels, whereas serum Lp(a) concentrations in patients with low-molecular-weight (LMW) isoforms were not significantly different from controls, except for CAPD patients, who presented increased serum Lp(a) concentrations. We conclude that in patients with renal failure, even of mild/moderate degree, as well as in patients with end-stage renal disease undergoing HD or CAPD, elevated Lp(a) concentrations are mainly observed in those with HMW apo(a) phenotypes.

Increased serum levels of interleukin-1beta in the systemic circulation of patients with essential hypertension: additional risk factor for atherogenesis in hypertensive patients?

The dysfunction of the immune system has been implicated in the cause of essential hypertension (EH). On the other hand, interleukin- 1beta (IL-1beta) has strongly been involved in the pathogenesis of atheromatosis, whereas our preliminary experiments in serum samples from hypertensive patients before any drug therapy have shown the presence of high concentrations of IL-1beta and the absence of interleukin-2 (IL-2). The aim of this study was first to confirm our preliminary findings and second to investigate the possible interrelation(s) among the parameters studied, particularly between the immunologic markers and the blood pressure or the lipid parameters, because so far there are no data regarding the possible participation of IL-1beta in the cascade phenomena presented during the process of EH such as atherogenesis. Serum samples from 28 consecutive unselected patients with EH before any drug administration or after discontinuation of the antihypertensive therapy for at least 4 weeks, 31 normotensive patients with familial hypercholesterolemia (FH, disease control group), and 35 healthy individuals In a control group matched for age and sex were investigated for the presence of IL-1beta (commercial enzyme immunoassay), soluble IL-2 receptors (slL-2Rs, sandwich enzyme-linked immunosorbent assay set up in our laboratory), and some of the acute phase proteins by nephelometry. In addition, total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, apolipoproteins A1 and B, and lipoprotein (a) were determined by standard methods. The data were analyzed by unpaired t test, Mann Whitney-U, chi-squared analysis after Yate's correction, analysis of variance, or Kruskal-Wallis where applicable. Correlation coefficient was calculated by simple regression analysis (r) or nonparametric Spearman correlation coefficient (rs). We found that (1) none of the patients had increased concentrations of sIL-2Rs, and (2) the IL-1beta levels significantly differed in the three groups (p = 0.0001). In more detail, the concentrations of IL-1beta were significantly higher in patients with EH compared with those in patients with FH (p < 0.0005) and the healthy control group (p = 0.0001). By contrast, the IL-1beta concentrations did not differ between patients with FH and the healthy control group. (3) Sixteen (57.1%) patients with EH and only 6 (19.4%) patients with FH (p < 0.01) had increased levels of IL-1beta, and (4) the IL-1beta was not correlated with the acute phase reactants or the lipid parameters in the groups studied. However, the group of patients with EH and increased IL-1beta levels had significantly higher mean concentrations of triglycerides (p < 0.05) and significantly lower mean concentrations of high-density lipoprotein cholesterol (p < 0.05) than those who had IL-1beta levels lower than the cutoff point. (5) The IL-1beta concentrations were positively though slightly correlated with the mean blood pressure only in the group of patients with EH (r = 0.38, p < 0.05). This study demonstrated the presence of high concentrations of IL-1beta and the absence of indicators of cellular immune activation in the systemic circulation of patients with EH, suggesting that this cytokine may be involved in the pathogenesis of EH. In addition, this study showed that the high levels of IL-1beta were associated with lipid indicators of atheromatosis only in the group of patients with EH. More studies are required in an attempt to address whether IL-1beta could have a pathogenetic importance in EH. Taking into account these findings, however, it can be suggested that the presence of high IL-1beta levels may be an additional and perhaps independent risk factor for atheromatosis in patients with EH.