Atherogenic lipoprotein phenotype and low-density lipoprotein size and subclasses in patients with growth hormone deficiency before and after short-term replacement therapy
Objective: Patients with growth hormone deficiency (GHD) have increased cardiovascular risk and may show elevated triglyceride and reduced high density lipoprotein (HDL) cholesterol concentrations, two lipid abnormalities usually accompanied by increased small dense LDL in the ‘atherogenic lipoprotein phenotype’ (ALP). In the present study, we directly investigated (1) whether hypopituitary patients with GHD have increased small dense LDL; (2) whether growth hormone replacement therapy (GHRT) beneficially impact on such particles; (3) the prevalence of ALP in GHD and GHRT patients. Design and methods: In 14 hypopituitary patients with GHD (44 ± 13 years, body mass index (BMI) 27 ± 3) before and after 4 months of GHRT, and in 11 healthy age- and BMI-matched controls we measured plasma lipids and LDL size and subclasses by gradient gel electrophoresis. Results: Compared with controls, GHD showed increased triglycerides (P = 0.0024), similar total and LDL cholesterol levels and a tendency towards reduced HDL cholesterol concentrations (P = 0.0894). GHRT reduced total and LDL cholesterol levels (P = 0.0303 and 0.0120 respectively), but no effect was found on triglycerides and HDL cholesterol levels. LDL size was unchanged in GHD versus controls (269 ± 9 vs 274 ± 6 Å, P = ns), but LDL subclass analysis revealed a shift towards more dense particles (P = 0.0046). GHRT had no significant impact on LDL size and subclasses. The prevalence of ALP was 14% in GHD and 7% in GHRT. Conclusions: In GHD patients, individual features of ALP (including increased small dense LDL) may be common, but complete ALP is relatively uncommon. Short-term replacement therapy seems to be ineffective on such lipid alterations, but the effect of a longer GHRT remains to be assessed.