The lactase persistence genotype is a protective factor for the metabolic syndrome.

The Metabolic Syndrome (MetS) is defined as a pattern of metabolic disturbances, which include central obesity, insulin resistance and hyperglycemia, dyslipidemia, and hypertension. Milk has been promoted as a healthy beverage that can improve the management of MetS. Most human adults, however, down-regulate the production of intestinal lactase after weaning. Lactase encoded by the LCT gene is necessary for lactose digestion. The -13910C > T SNP (rs4988235) is responsible for the lactase persistence phenotype in European populations. We herein investigated whether the lactase persistence genotype is also associated with the MetS in subjects from a Brazilian population of European descent. This study consisted of 334 individuals (average age of 41 years) genotyped by PCR-based methods for the -13910C > T SNP. Clinical data were assessed and the genotypes were tested for their independent contribution to the MetS using chi-square tests and multiple logistic regression analysis. Univariate analyses showed that hypertension and MetS prevalence were higher in individuals with the lactase non-persistence genotype than in lactase persistence subjects. Furthermore, lactase persistence was associated with a lower risk for MetS (OR = 0.467; 95% CI 0.264-0.824; p = 0.009). These results suggest that LCT genotypes can be a valuable tool for the management of MetS treatment.

ACE polymorphism and use of ACE inhibitors: effects on memory performance.

Memory is an important cognition function, being fundamental to the development and independence of individuals. Our aim was to investigate the influence apolipoprotein E (APOE) and angiotensin I-converting enzyme (ACE) polymorphism and ACE inhibitors use, besides their interaction on memory performance of healthy subjects over 50 years. The sample consisted of 205 subjects assessed for five types of episodic memory, using Wechsler Memory Scale-Revised (WMS-R), who answered a questionnaire about drug use and were assessed for the ACE insertion/deletion polymorphism and APOE polymorphism. We found no influence of the APOE gene. The use of ACE inhibitors beneficially influenced learning ability scores (p = 0.02). Besides, I allele carriers of ACE polymorphism showed higher verbal memory scores compared with homozygous DD. Also, we observed an interaction influencing learning ability between the ACE polymorphism and the use of inhibitors, the beneficial influence of the I allele was present only in individuals who make use of ACE inhibitors. We conclude that the ACE gene has influence on memory performance, and that this influence is modulated by ACE inhibitors use.

The influence of nutrigenetics on the lipid profile: interaction between genes and dietary habits.

Nutrigenetics is a new field with few studies in Latin America. Our aim is to investigate the way in which different genes related to the lipid profile influence the response to specific dietary habits. Eight polymorphisms on seven genes were investigated in a sample (n = 567) from Porto Alegre, RS, Brazil. All the volunteers completed a food diary that was then assessed and classified into nine food groups. A number of nutrigenetic interactions were detected primarily related to the apolipoprotein E (apoE) gene. For example, frequent consumption of foods rich in polyunsaturated fat resulted in the beneficial effect of increasing HDL-C only in individuals who were not carriers of the E*4 allele of the APOE gene, whereas variations in eating habits of E*4 carriers did not affect their HDL-C (P = 0.018). Our data demonstrate for the first time nutrigenetic interactions in a Brazilian population.

A telomerase em células-tronco hematopoéticas: [revisão] / Telomerase in hematopoietic stem cells: [review]

A proliferação das células-tronco hematopoéticas sofre a perda dos telômeros a cada divisão celular. Alguns autores discordam quanto à perda ou não do potencial proliferativo e capacidade de auto-renovação das células mais diferenciadas. Revisaremos aqui o papel da telomerase na biologia do sistema hematopoético, na diferenciação normal ou maligna, assim como no envelhecimento das células-tronco hematopoéticas. A constante renovação celular requerida pela hematopoese confere às células-tronco embrionárias, assim como à maioria das células tumorais, um aumento da capacidade proliferativa marcada pela detecção da enzima telomerase e possível manutenção dos telômeros. Estudos clínicos se farão necessários para esclarecer melhor a atividade da telomerase em células-tronco hematopoéticas, seu possível uso como marcador de diagnóstico e seu uso a fim de propósitos prognósticos.

Hematopoietic stem cell proliferation leads to telomere length decreases at each cellular division. Some authors disagree about the telomere influence on the reduction of the proliferative potential and capacity of self renewal. Here we review telomerase function in the biology of the hematopoietic system, in normal or differentiation and its influence on the ageing of hematopoietic stem cells. The constant cellular renewal required to maintain the hematopoietic system, provides embryonic stem cells, as well as malignant cells, an increased proliferative capacity. This is marked by the detection of telomerase enzyme activity and possible telomere maintenance. Clinical trials will be required to clarify telomerase activity in hematopoietic stem cells, its possible use as a diagnostic marker and its use for prognostic purposes.

ESR1 and APOE gene polymorphisms, serum lipids, and hormonal replacement therapy.

OBJECTIVES: The risks and benefits of hormone replacement therapy (HRT) are, at least in part, mediated by the metabolic individuality of women. Therefore, we investigated the association between polymorphisms at the estrogen receptor 1 gene (ESR1) and at the apolipoprotein E gene (APOE) with lipid and lipoprotein levels in order to verify whether these concentrations are modulated by these gene variants in women with different hormonal status. METHODS: One hundred and eighteen postmenopausal women using oral HRT with estrogen or estrogen plus progestagen (HRT+, mean age=56+/-6.7 years, 39-75 years) and 167 postmenopausal women that were not on HRT (HRT-, mean age=58+/-9.8 years, 38-85 years) participated in the study. The polymorphisms were genotyped by PCR-RFLP methods. RESULTS: No significant effect of ESR1 genotypes or haplotypes and ESR1*HRT interactions were detected on lipid levels in two-way analysis of variance. Postmenopausal women HRT nonusers carriers of the APOE*4 allele had higher T-chol and LDL-C levels than postmenopausal women HRT nonusers carriers of the APOE*3 and APOE*2 allele. T-chol and LDL-C concentrations in postmenopausal users of HRT that were APOE*4 carriers were similar to those in postmenopausal women nonusers of HRT homozygotes for APOE*3 and APOE*2 carriers. A significant APOE*4/HRT interaction was detected on T-chol and LDL-C levels by multiple regression analysis. CONCLUSION: The results from this study suggest that the HRT influence on T-chol and LDL-C levels is modulated by APOE isoforms but not by ESR1 polymorphisms.

O componente genético da determinação dos lipídeos séricos / The genetic component of serum lipid determination

Os níveis de lipídeos séricos são características multifatoriais determinadas por um grande número de fatores genéticos e ambientais. A identificação do componente genético dessas características tem sido intensamente investigada nos últimos anos. Esses estudos têm enfocado principalmente polimorfismos nos genes que codificam proteínas estruturais e enzimas relacionadas com o metabolismo de lipídeos. Estudos mais recentes mostraram que o efeito desses polimorfismos depende em parte das interações dos diferentes genótipos com os fatores de risco clássicos tais como tabagismo, sobrepeso ou sedentarismo. A variabilidade encontrada nesses genes parece também influir na resposta a fármacos comumente utilizados no tratamento das hiperlipidemias.