Reducing lipids for CV protection in CKD patients-current evidence

Pomegranate juice improves cardiometabolic risk factors, biomarkers of oxidative stress and inflammation in hemodialysis patients: a randomized crossover trial

BACKGROUND

Pomegranate has antioxidant, cardioprotective and anti-inflammatory properties. We designed a crossover study aimed at determining if consumption of pomegranate juice (PJ) improves lipid profile and oxidative and inflammatory biomarkers of hemodialysis patients. Forty-one hemodialysis patients were randomly assigned to one of two groups: PJ-treated group receiving 100 mL of natural PJ immediately after their dialysis session three times a week and the control group receiving the usual care. After 8 weeks, a 4-week washout period was established and then the role of the groups was exchanged. Lipid profile, blood pressure and oxidative and inflammatory biomarkers were measured before and after each sequence.

RESULTS

Based on the results of intention-to-treat analysis, triglycerides were decreased in PJ condition and increased in the controls. Conversely, high-density lipoprotein cholesterol was increased in PJ and decreased in the control group. Total and low-density lipoprotein cholesterol did not significantly change in either condition. Systolic and diastolic blood pressure significantly decreased in PJ condition. Total antioxidant capacity increased in PJ condition (P < 0.001) and decreased in the controls (P < 0.001). Conversely, malondialdehyde and interleukin-6 decreased in PJ (P < 0.001) and increased in the control group (P ≤ 0.001). The changes of these biomarkers were significantly different between the two conditions.

CONCLUSIONS

Eight-week PJ consumption showed beneficial effects on blood pressure, serum triglycerides, high-density lipoprotein cholesterol, oxidative stress and inflammation in hemodialysis patients. © 2019 Society of Chemical Industry.

Lipid Metabolism Disorder and Renal Fibrosis

Since the lipid nephrotoxicity hypothesis was proposed in 1982, increasing evidence has supported the hypothesis that lipid abnormalities contributed to the progression of glomerulosclerosis. In this chapter, we will discuss the general promises of the original hypothesis, focusing especially on the role of lipids and metabolic inflammation accompanying CKD in renal fibrosis and potential new strategies of prevention.

Dyslipidemia in patients with chronic kidney disease: etiology and management

Patients with chronic kidney disease (CKD), including those with end-stage renal disease, treated with dialysis, or renal transplant recipients have an increased risk for cardiovascular disease (CVD) morbidity and mortality. Dyslipidemia, often present in this patient population, is an important risk factor for CVD development. Specific quantitative and qualitative changes are seen at different stages of renal impairment and are associated with the degree of glomerular filtration rate declining. Patients with non-dialysis-dependent CKD have low high-density lipoproteins (HDL), normal or low total cholesterol (TC) and low-density lipoprotein (LDL) cholesterol, increased triglycerides as well as increased apolipoprotein B (apoB), lipoprotein(a) (Lp (a)), intermediate- and very-low-density lipoprotein (IDL, VLDL; “remnant particles”), and small dense LDL particles. In patients with nephrotic syndrome lipid profile is more atherogenic with increased TC, LDL, and triglycerides. Lipid profile in hemodialysis (HD) patients is usually similar to that in non-dialysis-dependent CKD patients. Patients on peritoneal dialysis (PD) have more altered dyslipidemia compared to HD patients, which is more atherogenic in nature. These differences may be attributed to PD per se but may also be associated with the selection of dialytic modality. In renal transplant recipients, TC, LDL, VLDL, and triglycerides are elevated, whereas HDL is significantly reduced. Many factors can influence post-transplant dyslipidemia including immunosuppressive agents. This patient population is obviously at high risk; hence, prompt diagnosis and management are required to improve their clinical outcomes. Various studies have shown statins to be effective in the cardiovascular risk reduction in patients with mild-to-moderate CKD as well as in renal transplant recipients. However, according to recent clinical randomized controlled trials (4D, A Study to Evaluate the Use of Rosuvastatin in Subjects on Regular Dialysis: an Assessment of Survival and Cardiovascular Events, and Study of Heart and Renal protection), these beneficial effects are uncertain in dialyzed patients. Therefore, further research for the most suitable treatment options is needed.

Plasma Nitration of High-Density and Low-Density Lipoproteins in Chronic Kidney Disease Patients Receiving Kidney Transplants

BACKGROUND

Functional abnormalities of high-density lipoprotein (HDL) could contribute to cardiovascular disease in chronic kidney disease patients. We measured a validated marker of HDL dysfunction, nitrated apolipoprotein A-I, in kidney transplant recipients to test the hypothesis that a functioning kidney transplant reduces serum nitrated apoA-I concentrations.

METHODS

Concentrations of nitrated apoA-I and apoB were measured using indirect sandwich ELISA assays on sera collected from each transplant subject before transplantation and at 1, 3, and 12 months after transplantation. Patients were excluded if they have history of diabetes, treatment with lipid-lowering medications or HIV protease inhibitors, prednisone dose > 15 mg/day, nephrotic range proteinuria, serum creatinine > 1.5 mg/dL, or active inflammatory disease. Sera from 18 transplanted patients were analyzed. Four subjects were excluded due to insufficient data. Twelve and eight patients had creatinine < 1.5 mg/dL at 3 and 12 months after transplantation, respectively. RESULTS. Nitrated apoA-I was significantly reduced at 12 months after transplantation (p = 0.039). The decrease in apoA-I nitration was associated with significant reduction in myeloperoxidase (MPO) activity (p = 0.047). In contrast to apoA-I, nitrated apoB was not affected after kidney transplantation.

CONCLUSIONS

Patients with well-functioning grafts had significant reduction in nitrated apoA-I 12 months after kidney transplantation. Further studies are needed in a large cohort to determine if nitrated apoA-I can be used as a valuable marker for cardiovascular risk stratification in chronic kidney disease.

Systolic pressure, diastolic pressure, or pulse pressure as a cardiovascular risk factor in renal disease

Chronic kidney disease is a leading global health problem with an increasing prevalence. Hypertension is present in most patients with chronic kidney disease, and hypertension-related nephrosclerosis is a top cause of progressive renal damage and end-stage renal disease. Systolic blood pressure (BP) and pulse pressure, together with nocturnal BP, are the most important factors favoring the progression of renal failure. Consequently, strict control of BP and other cardiovascular risk factors is required, including an adequate degree of suppression of the renin-angiotensin system in every patient.

Targeting residual risk: the rationale for the use of non-HDL cholesterol

There is a wealth of epidemiological and clinical data linking low-density lipoprotein cholesterol (LDLc) with atherosclerotic cardiovascular disease. Numerous primary and secondary prevention trials have demonstrated that reduction in LDLc leads to significant decrease in cardiovascular event rates. However, patients continue to be at significant risk for recurrent events despite aggressive LDLc lowering, reflecting a substantial residual risk. Numerous parameters like apolipoprotein B, LDL particle size, number and non-high density lipoprotein cholesterol (non-HDLc) measurement have been used to assess and address this high residual risk. Herein, we discuss the rationale and the evidence supporting the use of non-HDLc. We also discuss therapeutic options and provide a practical approach to residual risk reduction from a primary care perspective.

An update on the lipid nephrotoxicity hypothesis

When the 'lipid nephrotoxicity hypothesis' was proposed in 1982, it brought together several disparate experimental findings in hyperlipidemia and renal disease to suggest that concomitant hyperlipidemia and proteinuria would cause self-perpetuating renal disease once the initial glomerular insult was no longer present. This process would be analogous to atherosclerosis. Since 1982, increasing evidence has supported the hypothesis that lipid abnormalities contribute to both atherosclerosis and glomerulosclerosis. In this Review, we discuss research developments that are relevant to the lipid nephrotoxicity hypothesis. We describe how inflammatory stress accompanying chronic kidney disease modifies lipid homeostasis by increasing cholesterol uptake mediated by lipoprotein receptors, inhibiting cholesterol efflux mediated by the ATP-binding cassette transporter 1 and impairing cholesterol synthesis in peripheral cells. As a result of these events, cholesterol relocates to and accumulates in renal, vascular, hepatic and possibly other tissues. The combination of increased cellular cholesterol influx and reduced efflux causes injury in some tissues and lowers the plasma cholesterol level. In addition, inflammatory stress causes a degree of statin resistance via unknown mechanisms. These phenomena alter traditional understanding of the pathogenesis of lipid-mediated renal and vascular injury and could influence the clinical evaluation of renal and cardiovascular risk and the role of lipid-lowering treatment in affected patients.

Dyslipidemia of kidney disease

PURPOSE OF REVIEW

Chronic kidney disease is associated with specific alterations of lipoprotein metabolism that may be linked to accelerated atherosclerosis and cardiovascular disease. This review summarizes current knowledge of the pathophysiology of renal dyslipidemia and the therapeutic options.

RECENT FINDINGS

The renal dyslipidemia is characterized by accumulation of intact and partially metabolized triglyceride-rich apoB-containing and apoC-containing lipoproteins. Increased concentrations of atherogenic apoC-III rich lipoproteins, the hallmark of renal dyslipidemia, may result from disturbances of insulin metabolism and action in chronic kidney disease. Novel findings strongly suggest that apoC-III triggers a cascade of pro-inflammatory events, which ultimately can result in endothelial dysfunction and vascular damage. Disappointingly, recently reported intervention trials with statins have failed to show any benefit on cardiovascular disease in patients with advanced renal failure.

SUMMARY

During recent years, our understanding of the character and biological significance of the dyslipidemia of chronic kidney disease, and its link to cardiovascular disease, has increased. However, our knowledge about its proper management is still very limited.