Haptoglobin gene subtypes in three Brazilian population groups of different ethnicities

Haptoglobin is a plasma hemoglobin-binding protein that limits iron loss during normal erythrocyte turnover and hemolysis, thereby preventing oxidative damage mediated by iron excess in the circulation. Haptoglobin polymorphism in humans, characterized by the Hp*1 and Hp*2 alleles, results in distinct phenotypes known as Hp1-1, Hp2-1 and Hp2-2, whose frequencies vary according to the ethnic origin of the population. The Hp*1 allele has two subtypes, Hp*1F and Hp*1S, that also vary in their frequencies among populations worldwide. In this work, we examined the distribution frequencies of haptoglobin subtypes in three Brazilian population groups of different ethnicities. The haptoglobin genotypes of Kayabi Amerindians (n = 56), Kalunga Afro-descendants (n = 70) and an urban population (n = 132) were determined by allele-specific PCR. The Hp*1F allele frequency was highest in Kalunga (29.3%) and lowest in Kayabi (2.6%). The Hp*1F/Hp*1S allele frequency ratios were 0.6, 1.0 and 0.26 for the Kayabi, Kalunga and urban populations, respectively. This variation was attributable largely to the Hp*1F allele. However, despite the large variation in Hp*1F frequencies, results of FST (0.0291) indicated slight genetic differentiation among subpopulations of the general Brazilian population studied here. This is the first Brazilian report of variations in the Hp *1F and Hp*1S frequencies among non-Amerindian Brazilians

Estudos dos polimorfismos genéticos de enzimas antioxidantes associados à suscetibilidade aos danos no DNA induzidos pelo peróxido de hidrogênio

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Ciências da Saúde, 2009.Organismos aeróbicos estão sujeitos aos intermediários reativos gerados durante a respiração celular. Esses são caracterizados como EROS (Espécies Reativas ao Oxigênio) responsável pelo aumento do estresse oxidativo e conseqüentes danos ao DNA. O organismo desenvolveu um mecanismo de detoxificação no qual as enzimas antioxidantes endógenas, catalase, superóxido dismutase, glutationa peroxidase, e haptoglobina agem sobre os EROS reduzindo possíveis danos no DNA. Diversos estudos associam o polimorfismo dessas enzimas ao risco do desenvolvimento de patologias. O presente estudo observou se a variabilidade genética da região promotora da catalase (21A/T), hGPX1 (Pro198Leu), SOD2(Val-9Ala) e haptoglobina confere diferença na proteção ao estresse oxidativo promovido pelo peróxido de hidrogênio nas concentrações de 250μM e 1mM em indivíduos jovens e saudáveis de Brasília. A variação das enzimas antioxidantes endógenas avaliadas, sugere conferir diferentes graus de proteção ao DNA contra o estresse oxidativo, induzido in vitro pelo peróxido de hidrogênio em indivíduos jovens e saudáveis da população de Brasília. _______________________________________________________________________________________ ABSTRACTAerobic organisms are subjected to reactive intermediaries that are generated during cell breathing. They are characterized as ROS (Reactive Oxygen Species), which are responsible for oxidative stress increase and damages to DNA. T h e organism developed a detoxification mechanism in which the endogenous anti-oxidant enzymes catalase, superoxide dismutase, glutathione peroxidase and haptoglobin act on ROS reducing possible damages to DNA. Many studies have associated these enzyme polymorphisms and the development of pathologies. T he present study observed if the genetic variability of the promoting catalase region (21A/T), hGPX1 (Pro/Leu), SOD2 ( Val/9Ala) and haptoglobin concede difference in the protection of oxidative stress, by H2O2 within concentrations of 250μM and 1mM in healthy, young subjects from Brasilia. T he variation by endogenous anti-oxidants enzymes avaliated in this study, suggest confer levels differents the DNA protection to oxidative stress, in vitro, by H2O2

Genetic polymorphisms influence runners’ responses to the dietary ingestion of antioxidant supplementation based on pequi oil (Caryocar brasiliense Camb.): a before-after study

Genes have been implicated in the levels of oxidative stress, lipids, CVD risk, immune reactivity, and performance. Pequi oil (Caryocar brasiliense) has shown anti-inflammatory and hypotensive effects, besides reducing exercise-induced DNA, tissue damages, and anisocytosis. Given that diet can interact with the human genome to influence health and disease, and because genetic variability can influence response to diet, we aim to investigate the influence of 12 gene polymorphisms on inflammatory markers, postprandial lipids, arterial pressure, and plasma lipid peroxidation of runners (N = 125), before and after 14 days of 400 mg pequi-oil supplementation, after races under closely comparable conditions. Arterial pressure was checked before races; blood samples were taken immediately after racing to perform leukogram and plateletgram, Tbars assay, lipid, and CRP dosages and genotyping. CAT, GST-M1/T1, CRP-G1059C, and MTHFR-C677T polymorphisms influenced post-pequi-oil responses in leukogram; Hp and MTHFR-C677T, in plateletgram; Hp, ACE, GSTT1, and MTHFR-A1298C, in lipid profile; MTHFR-A1298C, in C-reactive protein (CRP) levels; and Hp and MnSOD, in Tbars assay. Differences between ACE genotypes in leukogram and total cholesterol disappeared after pequi, and the same occurred for Hp and MnSOD in Tbars assay and for MTHFR-A1298C with CRP levels. Because genetic inheritance is one of the factors that drive atherosclerosis-related lipid abnormalities, results can contribute to a greater understanding of the influence of genetic polymorphisms in situations that push up free radicals. Knowledge is also expanded on how antioxidant supplementation affects an individual’s genes and how athletic genetic makeup can affect the way a person responds to antioxidant supplements