High-density lipoprotein cholesterol esterification and transfer rates to lighter density lipoproteins mediated by cholesteryl ester transfer protein in the fasting and postprandial periods are not altered in type 1 diabetes mellitus

HDL functionality in type 1 diabetes

Type 1 diabetes (T1D) is a chronic autoimmune disease characterized by absence of insulin secretion due to destruction of the pancreatic beta-cells. Patients with T1D exhibit an increased risk for cardiovascular disease (CVD) compared with non-diabetic subjects. It has been established that low concentration of high-density lipoprotein cholesterol (HDL-C), an independent risk marker of CVD, coincides with a reduced protective capacity against oxidative stress. However, conflicting results have been reported on the prevalence of low HDL-C levels in T1D. Interestingly, changes in composition and function of HDL particles (abnormal ratio of cholesteryl ester-to-triglyceride, reduction in the phospholipid content, reduced capacity to promote cholesterol efflux from macrophages, impaired anti-inflammatory and anti-oxidant activities) have been described in patients with T1D. Hence, exploring HDL function, even in the presence of normal HDL-C levels, might provide additional insight into the underlying pathophysiology associated with increased CV risk in T1D. In the current review, we will provide a detailed overview of the current evidence for a role of HDL function as independent risk factor for the development of CVD in T1D.

The lipoprotein lipase S447X and cholesteryl ester transfer protein rs5882 polymorphisms and their relationship with lipid profile in human serum of obese individuals

BACKGROUND

Obesity is often associated with an alter lipid profile, e.g., raised serum triglycerides (TG) and low high-density lipoprotein (HDL) cholesterol levels, both important risk factor for cardiovascular-diseases. The aim of current study was to explore the association of a polymorphism of the lipoprotein lipase (LPL) rs328 and cholesteryl-ester-transfer-protein (CETP) rs5882 genes in relation to lipid profile in subjects with/without obesity.

SUBJECTS/METHODS

Genotyping was carried out in 271 individuals, (151 obese subjects and 120 non-obese). Univariate/multivariate analyses were conducted to evaluate the association of these genetic-polymorphisms with obesity and lipid components.

RESULTS

Obese subjects had a significantly (P<0.05) higher level of triglyceride (TG), blood pressure, waist-circumference and fasting-blood-glucose, and lower level of HDL-C. LPL and CETP polymorphisms were not associated with obesity in our population. However, the LPL rs328-GG-GC genotype was significantly related to a higher concentration of TG, compared to the CC wild-type; and a higher HDL-C level in the obesity-group with respect to the control group. Moreover, obese-subjects carrying the G allele of CETP had a significantly lower level of HDL-C (P<0.05) compared to those with C allele.

CONCLUSION

We demonstrate a significant association of LPL and CETP polymorphisms with serum triglycerides and HDL-cholesterol.

Transferência de lípides para a lipoproteína de alta densidade (HDl) em mulheres com diabetes melito tipo 1

INTRODUÇÃO: Os portadores de diabetes melito tipo 1 (DM1) possuem aumentado risco de doença cardiovascular e, ainda assim, podem apresentar perfil lipídico normal. Para esclarecer se os níveis normais de HDL podem ocultar defeitos na função, foram estudados a transferência de lípides para a HDL em DM1. MÉTODOS: Vinte e uma mulheres jovens portadoras de DM1 foram comparadas com 21 mulheres não-diabéticas. Nanoemulsões foram usadas como doadoras de lípides para HDL: uma marcada com ³H-triglicérides e 14C-colesterol livre e outra com ³H-éster de colesterol e 14C-fosfolípides. Após 1 hora de incubação com amostras de plasma, seguida por precipitação química, o sobrenadante, contendo HDL, teve a radioatividade contada. RESULTADOS: Nenhuma diferença foi encontrada nas transferências dos ésteres de colesterol, triglicérides, colesterol livre e fosfolípides para as HDL. CONCLUSÃO: A transferência de lípides para a HDL não está afetada em portadoras de DM1. Isso sugere que a doença não altera a composição de lipoproteínas e a ação de proteínas de transferência.

Effects of cholesterol ester transfer protein (CETP) gene on adiposity in response to long-term overfeeding

Cholesterol ester transfer protein (CETP) plays a key role in remodeling triglyceride-rich particles and high-density lipoproteins (HDL). We investigated CETP sequence variants in response to long-term overfeeding (100 days) in 12 pairs of male monozygotic twins (mean age+/-S.D.: 21+/-2 years). Body fat mass (FM), abdominal subcutaneous (ASF) and visceral fat (AVF), and plasma lipoproteins were determined. The CETP variants C>T/In9 (rs289714) and G>A/Ex14 (rs5882, or I405V) were investigated by RFLP-PCR methodologies. Before overfeeding, the CETP CC/In9 (n=18) genotype was associated with lower FM compared to the C>T/In9 heterozygotes. Overfeeding induced more FM and ASF accretion in C>T/In9 carriers (P<or=0.05). CETP V405V homozygotes (n=8) had lower BMI, FM, and ASF before overfeeding than those with the I405I (n=6) or I405V (n=10) genotypes. However, V405V subjects had the largest gain in AVF with overfeeding (P=0.02). Decreases from baseline were significantly different across the I405V genotypes for HDL-C, HDL-Apo AI, HDL(2), and HDL(3) (P<or=0.05). Our data suggests that CETP sequence variation contributes to the undesirable changes in adiposity and HDL-C levels when exposed to excessive calorie consumption and may be potentially helpful to identify individuals with the metabolic syndrome who are at higher risk of cardiovascular disease.