FADS Polymorphisms Affect the Clinical and Biochemical Phenotypes of Metabolic Syndrome.

Long-chain polyunsaturated fatty acids (LC-PUFAs) play important roles in human health, from controlling inflammation to lipid and glucose homeostasis. In our previous study, which employed a cluster analysis of a plasma fatty acid (FA) pattern, we identified two clusters of metabolic syndrome (MetS) independent of clinical and biochemical parameters within the whole study group (controls together with metabolic syndrome (MetS) patients). FA desaturase (FADS) genes are the key regulators of LC-PUFA metabolism. The aim of this study was to analyze associations between FADS polymorphisms and clusters of MetS. The study group consisted of 188 controls and 166 patients with MetS. The first cluster contained 71 controls (CON1) and 109 MetS patients (MetS1). The second cluster consisted of 117 controls (CON2) and 57 MetS patients (MetS2). In comparison with MetS2, cluster MetS1 displayed a more adverse risk profile. Cluster CON1 had, in comparison with CON2, higher body weight and increased triacylglycerol levels (p < 0.05). We found that the FADS rs174537 (p < 0.001), rs174570 (p < 0.01), and rs174602 (p < 0.05) polymorphisms along with two inferred haplotypes had statistically significant genotype associations with the splitting of MetS into MetS1 and MetS2. Conversely, we observed no significant differences in the distribution of FADS polymorphisms between MetS and CON subjects, or between CON1 and CON2. These associations between FADS polymorphisms and two clusters of MetS (differing in waist circumference, HOMA-IR, lipolysis, and oxidative stress) implicate the important influence of genetic factors on the phenotypic manifestation of MetS.

[Desaturases of fatty acids (FADS) and their physiological and clinical implication]. / Desaturázy mastných kyselin: patofyziologie a klinický význam.

States associated with insulin resistance, as overweight/obesity, type 2 diabetes mellitus (DM2), cardiovascular diseases (CVD), some cancers and neuropsychiatric diseases are characterized with a decrease of long-chain polyunsaturated fatty acids (LC-PUFA) levels. Amounts of LC-PUFA depend on the exogenous intake of their precursors [linoleic (LA) and α-linolenic acid (ALA)] and by rate of their metabolism, which is influenced by activities of enzymes, such as Δ6-desaturase (D6D, FADS2), D5D, FADS1, elongases (Elovl2, -5, 6).Altered activities of D5D/D6D were described in plenty of diseases, e.g. neuropsychiatric (depressive disorders, bipolar disorder, dementia), metabolic (obesity, metabolic syndrome, DM2) and cardiovascular diseases (arterial hypertension, coronary heart disease), inflammatory states and allergy (Crohns disease, atopic eczema) or some malignancies. Similar results were obtained in studies dealing with the associations between genotypes/haplotypes of FADS1/FADS2 and above mentioned diseases, or interactions of dietary intake of LA and ALA on one hand and of the polymorphisms of minor allels of FADS1/FADS2, usually characterized by lower activities, on the other hand.The decrease of the desaturases activities leads to decreased concentrations of products with concomitant increased concentrations of substrates. Associations of some SNP FADS with coronary heart disease, concentrations of plasma lipids, oxidative stress, glucose homeostasis, and inflammatory reaction, were described. Experimental studies on animal models and occurrence of rare diseases, associated with missing or with marked fall activities of D5D/D6D emphasized the significance of desaturases for healthy development of organism as well as for pathogenesis of some disease.

Xanthomas: clinical and pathophysiological relations.

BACKGROUND: Xanthomas are well circumscribed lesions in the connective tissue of the skin, tendons or fasciae that predominantly consist of foam cells; these specific cells are formed from macrophages as a result of an excessive uptake of low density lipoprotein (LDL) particles and their oxidative modification. RESULTS: Until recently, xanthelasma was considered to be only a cosmetic lesion; however, according to the results of recent prospective studies it is connected with an increased cardiovascular risk and reduced average lifespan. Pathogenetic mechanisms involved in the development of xanthomas resemble early stages of atherogenesis. In clinical practice, xanthomas can signalise various congenital or acquired dyslipidemias. The most prevalent form of xanthomas is xanthelasma palpebrarum. Tendinous and tuberous xanthomas are typical for autosomal dominant hypercholesterolemia, as well as for some rare conditions, such as cerebrotendinous xanthomatosis and familial ß-sitosterolemia. In patients with familial hypercholesterolemia, the presence of tendinous xanthomas has been shown to be associated with a two to four times higher risk for cardiovascular disease. Eruptive xanthomas are skin manifestations of a severe hypertriglyceridemia and implicate an elevated risk for acute pancreatitis or type 2 diabetes mellitus. Xanthoma striatum palmare is pathognomic for primary dysbetalipoproteinemia, whereas diffuse plane xanthomas are frequently associated with paraproteinemia and lymphoproliferative disorders. CONCLUSION: Thorough familiarity with the clinical presentation of xanthomas helps in the diagnosis and follow-up of different forms of dyslipidemia. Moreover, xanthelasma palpebrarum, the most prevalent form of xanthomas, is connected with increased risk of atherothrombotic disease independently of conventional cardiovascular risk factors. To fully understand the pathogenesis, further experimental and clinical research is required.

N-3 polyunsaturated fatty acids in the treatment of atherogenic dyslipidemia.

BACKGROUND: Atherogenic dyslipidemia contributes substantially to the residual cardiovascular risk. The aim of this study was to examine the effects of therapeutic doses of n-3 polyunsaturated fatty acids on the three major lipid abnormalities of atherogenic dyslipidemia, i.e. hypertriacylglycerolemia, low HDL cholesterol, and increased levels of small dense LDL particles, as well as on some new risk factors. MATERIALS AND METHODS: A total of 60 hypertriacylglycerolemic patients were included in the study. Group S consisted of 36 patients who were already treated with statins, Group N of 24 patients not yet treated. Each patient was examined after six weeks on placebo and six weeks of treatment with n-3 PUFA (eicosapentaenoic and docosahexaenoic acid ethyl esters, 3.0 g/d). RESULTS: Treatment with n-3 PUFA caused a decrease in plasma triacylglycerols (28%, p<0.001), and VLDL (-27%, p<0.001), an increase in HDL-C (+4%, p<0.01), and a decrease in sdLDL cholesterol (-16%, p<0.05). These changes were accompanied by a decrease in microalbuminuria (-30%, p<0.05), as well as in several parameters of oxidative stress. Analysis of the fatty acids composition of plasma phospholipids showed a significant increase in all n-3 PUFAs examined, accompanied by a decrease in n-6 PUFAs, as well as in monounsaturated acids. No significant differences in the effects of n-3 PUFA were found between the Groups S and N. CONCLUSION: Our results support the opinion that hypertriacylglycerolemic patients benefit from the treatment with n-3 PUFA which improves several important metabolic factors of cardiovascular risk.

[Renin, prorenin, and the direct renin inhibitor aliskiren]. / Renin, prorenin a prímý inhibitor reninu aliskiren.

The renin-angiotensin system plays an important role in various physiological and pathophysiological regulatory mechanisms. Within the past few years, the classical concept of a linear enzymatic cascade has experienced substantial changes. A parallel counterregulatory axis has been identified which involves the angiotensin converting enzyme homologue ACE2, angiotensin (1-7), and receptors Mas. The research in prorenin and its non-proteolytic activation has greatly advanced after the discovery of cellular receptors (P)RR; binding of renin or prorenin to these receptors not only facilitates angiotensin generation, but at the same time activates specific signal transduction pathways. The long-term search for clinically useful direct renin inhibitors has recently succeeded with the new antihypertensive drug aliskiren. While beneficial effects of aliskiren on some markers of cardiovascular and renal diseases have been proved in large clinical studies, important questions remain to be solved.

The influence of polymorphism of -493G/T MTP gene promoter and metabolic syndrome on lipids, fatty acids and oxidative stress.

The aim of this study was to investigate the effect of the microsomal triglyceride transfer protein (MTP) -493G/T polymorphism on clinical and biochemical parameters in relation to the presence of metabolic syndrome (MS). A group of 270 participants, 143 men and 127 women [50 men/36 women fulfilled the International Diabetes Federation (IDF) criteria of MS], was categorized on the basis of the MTP -493G/T polymorphism: GG homozygotes (Group GG) and carriers of the T allele (Group TT+TG). In men with MS, the presence of the T allele was associated with elevated concentrations of plasma insulin (by 48%, P<.01) and nonesterified fatty acids (by 49%, P<.05); homeostasis model assessment for insulin resistance index was higher by 64% (P<.05). Carriers of the T allele were further characterized by elevated plasma concentrations of total cholesterol (by 14%, P<.05) and by increased triglycerides in plasma (by 95%, P<.01) and in very low-density lipoprotein (by 106%, P<.01). They also had lower concentrations of n-6 polyunsaturated fatty acids in plasma phospholipids (by 3.5%, P<.05), lower Delta5-desaturase activities (by 18%, P<.05) and elevated concentrations of conjugated dienes in low-density lipoprotein (by 29%, P<.01). No significant differences between Groups GG and TT+TG were found in men without MS and in women with and without MS. Our results imply evidence for interactive effects of genetic, metabolic and gender-specific factors on several components of metabolic syndrome, which can increase the risk for cardiovascular disease.