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Familial hypercholesterolemia (FH) is associated with heterogeneity of the onset and severity of coronary heart disease (CHD). In this study, we investigated different low-grade proinflammatory markers and the atheroprotective function of the [HDL.sub.3] subfraction in FH-patients (n = 13) with identical LDL-receptor mutations and in age- and sex-matched healthy controls (n = 11). Compared with healthy controls, FH-patients had greater gene expressions of the proatherogenic mediators TNF-[alpha] and IL-8 in circulating peripheral blood mononuclear cells. In addition, they had a higher serum concentration of intercellular adhesion molecule-1 (ICAM-1) and a lower net antioxidant capacity. FH-derived [HDL.sub.3] with a high level of triglycerides had a reduced capacity to inhibit the release of IL-8 from TNF-[alpha]-stimulated human umbilical vein endothelial cells (HUVEC) [1.864 mg/L (1.461-2.208 mg/L) vs. 1.466 mg/L (1.225-1.643 mg/L); P < 0.05; median (range)], and a reduced capacity to promote cholesterol efflux from lipid-loaded macrophages [12% (12-14%) vs. 15% (14-18%); P < 0.05; median (range)] compared with [HDL.sub.3] with a lower triglyceride content. Notably, the degree of inhibition of IL-8 release from HUVEC by [HDL.sub.3] was correlated with the ability of [HDL.sub.3] to promote cholesterol efflux (r = 0.80, P = 0.03). In conclusion, compared with healthy controls, FH-patients are characterized by higher levels of low-grade proinflammatory markers, and FH-derived [HDL.sub.3] with high triglyceride content may be more proatherogenic. These triglyceride rich-[HDL.sub.3] might be partly responsible for the phenotypic variation among FH-patients with identical LDL-receptor mutations. KEY WORDS: * familial hypercholesterolemia; high density lipoprotein * coronary heart disease * cytokines * cholesterol efflux

An elevated plasma concentration of homocysteine is an independent risk factor for cardiovascular disease. However, the mechanisms are still unclear. Lectinlike oxidized LDL receptor-1 (LOX-l) has ligand specificity for oxidized LDL (oxLDL). We hypothesized that homocysteine's atherogenic effects may involve LOX-l-mediated mechanisms. We examined the effect of folic acid supplementation for 6 wk and 12 mo (5 mg/d for 1 wk, 1 mg/d for 37 wk and 0.4 mg/d for the remaining 14 wk) on LOX-1 mRNA levels and on oxLDL-induced release of tumor necrosis factor [alpha] from peripheral blood mononuclear cells in hyperhomocysteinemic individuals. Compared with healthy controls, hyperhomocysteinemic subjects had elevated mRNA levels of LOX-1 in mononuclear cells (P < 0.001), and their mononuclear cells released more tumor necrosis factor [alpha] (TNF[alpha]) upon oxLDL stimulation (P = 0.01). This oxLDLstimulated release of TNF[alpha] correlated with LOX-1 expression (r = 0.57, P = 0.026). Folic acid treatment led to a normalization of homocysteine levels accompanied by a reduction in LOX-1 gene expression (P < 0.02) and in oxLDL-stimulated release of TNF[alpha] (P < 0.05). These novel findings suggest both that homocysteine exerts its atherogenic effect in part by elevating levels of LOX-l, thereby enhancing oxLDL-induced inflammatory responses, and most important, that folic acid supplementation may downregulate these responses. KEY WORDS: * homocysteine * folic acid * chemokines * PBMC * inflammation

Abstract Background The liver X receptors (LXR) α and β regulate lipid and carbohydrate homeostasis and inflammation. Lxrβ-/- mice are glucose intolerant and at the same time lean. We aimed to assess the associations between single nucleotide polymorphisms (SNPs) in LXRβ and risk of type 2 diabetes mellitus (T2DM), obesity and related traits in 3 separate cohort studies. Methods Twenty LXRβ SNPs were identified by sequencing and genotyped in the HUNT2 adult nested case-control study for T2DM (n = 835 cases/1986 controls). Five tag-SNPs (rs17373080, rs2695121, rs56151148, rs2303044 and rs3219281), covering 99.3% of the entire common genetic variability of the LXRβ gene were identified and genotyped in the French MONICA adult study (n = 2318) and the European adolescent HELENA cross-sectional study (n = 1144). In silico and in vitro functionality studies were performed. Results We identified suggestive or significant associations between rs17373080 and the risk of (i) T2DM in HUNT2 (OR = 0.82, p = 0.03), (ii) obesity in MONICA (OR = 1.26, p = 0.05) and (iii) overweight/obesity in HELENA (OR = 1.59, p = 0.002). An intron 4 SNP (rs28514894, a perfect proxy for rs17373080) could potentially create binding sites for hepatic nuclear factor 4 alpha (HNF4α) and nuclear factor 1 (NF1). The C allele of rs28514894 was associated with ~1.25-fold higher human LXRβ basal promoter activity in vitro. However, no differences between alleles in terms of DNA binding and reporter gene transactivation by HNF4α or NF1 were observed. Conclusions Our results suggest that rs17373080 in LXRβ is associated with T2DM and obesity, maybe via altered LXRβ expression.

Inflammatory processes including increased activation of chemokines play an important role in atherogenesis. Patients with hyperhomocysteinemia have increased risk for cardiovascular events that potentially involve enhanced inflammation. Statins may have anti-inflammatory actions at least partly independent on their lipid-lowering effects. In the present study we examined the association between statins and chemokine levels in patients with hyperhomocysteinemia. Our major findings were (i) patients with hyperhomocysteinemia on statin treatment ( n = 14) have significantly lower plasma levels of the CXC chemokine epithelial neutrophil activating peptide (ENA)-78 compared to hyperhomocysteinemic patients not on statin treatment ( n = 8). In fact, levels of ENA-78 in statin-treated patients did not differ from those of healthy controls ( n = 17); (ii) plasma levels of ENA-78 and growth-related oncogene (GRO)α correlated with levels of LDL-cholesterol and homocysteine; (iii) in contrast, plasma levels of the CC chemokine monocyte chemoattractant peptide (MCP)-1 were similar between statin-users, non-statin users and controls, and did not correlate with levels of LDL-cholesterol or homocysteine; and (iv) in vitro studies showed that simvastatin significantly reduced release of ENA-78, GROα and MCP-1 from peripheral blood mononuclear cells in healthy controls ( n = 7) in a concentration-dependent manner, without affecting release of RANTES. Our data may suggest that ENA-78 and GROα may be involved in the inflammatory arm of atherogenesis in patients with elevated risk of cardiovascular disease, with potential down-regulatory effect of statins. [ABSTRACT FROM AUTHOR]

High plasma homocysteine concentrations have been associated with increased risk of cardiovascular disease, whereas plasma HDL concentration is inversely correlated to such disorders. We hypothesized that hyperhomocysteinemic subjects may have dysfunctional HDL. We therefore investigated the ability of serum from hyperhomocysteinemic male and female subjects (n = 10) and control subjects (n = 10) to induce cholesterol efflux and to inhibit release of inflammatory mediators from human umbilical vein endothelial cell. We found that serum from hyperhomocysteinemic subjects had impaired ability to induce cholesterol efflux from lipid-loaded macrophages compared with healthy controls. HDL from those with markedly raised homocysteine concentrations had a reduced antiinflammatory effect in tumor necrosis factor-α-activated endothelial cells with an attenuated suppressive effect on interleukin-6 growth-related oncogene-a release. Also, the activity of paraoxonase in serum, a multifunctional enzyme with antioxidative effects in relation to the function of HDL, was significantly reduced in hyperhomocysteinemic subjects, in particular those with markedly raised homocysteine concentration. Our findings suggest that hyperhomocysteinemic individuals have dysfunctional HDL particles with attenuated antiatherogenic activity and may represent a novel explanation for the increased risk of cardiovascular events in these individuals. [ABSTRACT FROM AUTHOR]

Aims Familial hypercholesterolaemia (FH) is associated with increased risk of premature atherosclerosis and coronary artery disease (CAD). However, onset of clinically manifested CAD varies widely among patients with heterozygous FH, and we hypothesized that inflammatory mediators such as chemokines could contribute to atherogenesis in these patients.Methods and results We compared peripheral blood mononuclear cells (PBMCs) from FH patients with an identical mutation with PBMCs from sex- and age-matched healthy controls with respect to spontaneous and oxidized low density lipoprotein (oxLDL)-stimulated release of chemokines. Our main findings were: (1) PBMCs from FH patients spontaneously released significantly higher levels of macrophage inflammatory protein (MIP)-1α, MIP-1β and interleukin (IL)-8, and had a significantly lower oxLDL-stimulatory ratio for MIP-1α and MIP-1β than cells from healthy controls. (2) Spontaneous release of these chemokines correlated positively and stimulatory ratio correlated negatively with plasma concentrations of total and LDL cholesterol. (3) Among FH patients, release of MIP-1α, MIP-1β and IL-8 from PBMCs varied with the presence of xanthomas/xanthelasms, smoking and gender. (4) In vitro studies showed that FH serum but not control serum was able to induce enhanced spontaneous release of chemokines in PBMCs from both FH patients and control subjects.Conclusions Our data may suggest that a pathophysiological consequence of FH is enhanced chemokine responses, which in turn may promote recruitment and activation of leukocytes within the vessel wall, contributing to atherosclerosis as well as to the different phenotypes in these patients with an identical FH mutation. [ABSTRACT FROM PUBLISHER]