Small dense low-density lipoprotein in renal transplant recipients: a potential target for prevention of cardiovascular complications?

BACKGROUND: Immunosuppressive therapy is frequently associated with dyslipidemia, which is involved in cardiovascular morbidity and mortality in transplant patients. Beyond classical factors, such as low-density lipoprotein (LDL) cholesterol (LDL-C), qualitative abnormalities of lipoproteins, such as presence of the atherogenic factor, small dense LDL, may be of interest for a cardiovascular risk assessment. This study was designed to explore LDL size in renal transplant recipients in relation to quantitative lipid parameters and apolipoprotein (apo) CIII polymorphism.

METHODS: Total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), LDL-C, apoA1, apoB, apoCIII, and LDL size were measured in 62 patients of mean age 45 +/- 13 years including 71% men at 2 +/- 0.5 years after renal transplantation. Thirty-two patients received cyclosporine (CsA), while 30 received tacrolimus (FK). ApoCIII Sstl genotype was determined by restriction fragment length polymorphism.

RESULTS: The CsA group exhibited higher TC (P = .001), LDL-C (P = .004), non-HDL-C (P = .009), HDL-C (P = .03), apoB (P = .008), and apoCIII (P = .002) levels than the FK group. However, LDL-C (CsA: 3.7 +/- 1.2, FK: 3.0 +/- 0.6 mmol/L) and triglyceride levels (CsA: 1.55 mmol/L, FK: 1.37 mmol/L) were near the normal range in both groups. Allelic frequency of the sparse A2 allele associated with hypertriglyceridemia was 6%, similar to the general population. LDL size, which was comparable in the CsA and FK groups (25.87 +/- 0.89 vs 25.75 +/- 0.62 nm, respectively), inversely correlated with TG/HDL ratio (P = 10(-4)). Prevalence of small dense LDL (defined as <25.5 nm) was 26% in the CsA group and 33% in the FK group.

CONCLUSION: After LDL-C goal has been achieved, LDL size modulation may be taken into account in order to prevent cardiovascular complications.