Cross-sectional study of risk factors for atherosclerosis in the Azorean population.

BACKGROUND: Atherosclerosis-a major cause of vascular disease, including ischemic heart disease (IHD), is a pathology that has a two-fold higher mortality rate in the Azorean Islands compared to mainland Portugal. AIM: This cross-sectional study investigated the role of genetic variation in the prevalence of atherosclerosis in this population. SUBJECTS AND METHODS: A total of 305 individuals were characterized for polymorphisms in eight susceptibility genes for atherosclerosis: ACE, PAI1, NOS3, LTA, FGB, ITGB3, PON1 and APOE. Data were analysed with respect to phenotypic characteristics such as blood pressure, lipid profile, life-style risk factors and familial history of myocardial infarction. RESULTS: In the total sample, frequencies for hypercholestrolemic, hypertensive and obese individuals were 63.6%, 39.3% and 23.3%, respectively. The genetic profile was similar to that observed in other European populations, namely in mainland Portugal. No over-representation of risk alleles was evidenced in this sample. CONCLUSIONS: One has to consider the possibility of an important non-genetic influence on the high cholesterolemia present in the Azorean population. Since diet is the most important life-style risk factor for dyslipidemia, studies aiming to evaluate the dietary characteristics of this population and its impact on serum lipid levels will be of major importance.

Human mitochondrial variants influence on oxygen consumption.

This work investigates if human mitochondrial variants influence on maximal oxygen consumption (VO(2max)). With this purpose we recruited, as a uniform population in term of nutritional habits and life style, 114 healthy male Spanish subjects that practiced fitness exercises 3-4 times a week. Once mtDNA haplogroups were determined, we found that J presents with lower VO(2max) (P=0.02) than nonJ variants. J has been related with a lower efficiency of electron transport chain (ETC), diminished ATP and ROS production. Thus, the difficult to compensate the mitochondrial energetic deficiency could explain the accumulation of J haplogroup in LHON and multiple sclerosis. Furthermore, the lower ROS production associated to J could also account for the accrual of this variant in elderly people consequent to a decreased oxidative damage.

Association of human mitochondrial DNA variants with plasma LDL levels.

Increasing evidence supports the relationship between mitochondrial DNA variability and differences in energy metabolism, which may have pathophenotypic consequences. MtDNA pathological mutation has been also described to be associated with hypercholesterolemia. The target of this work consisted in studying the possible existence of an association between the mitochondrial DNA variability and plasma cholesterol levels. For this, two populations of 61 sedentary and 83 sportsmen were used to estimate the association of the lipidemic levels with the mitochondrial DNA variant harboured by them. Triglycerides, HDL-c, LDL-c and cholesterol/HDL-c were essayed, and mitochondrial DNA polymorphisms were assessed by HVR I sequencing and PCR/RFLP analysis. Major Caucasian mtDNA clades (HV, JT, U and IWX) did not associate with lipidemic levels in the sedentary population. However, in the case of a more disciplined population in term of nutritional habits and life style as sportsmen are, a significantly higher and lower level of LDL-c was associated with HV and JT clade, respectively. This observation could have relevant significance for metabolic distress diseases affecting plasma cholesterol levels.

[Deletions of the mitochondrial DNA associated to chronic progressive external ophthalmoplegia with ragged-red fibers in 2 Brazilian patients]. / Deleciones en el ADN mitocondrial asociadas a oftalmoplejía crónica extrínseca progresiva con fibras rojas rasgadas en 2 pacientes brasileños.

BACKGROUND AND OBJECTIVE: Our purpose was to report the neurological manifestations and molecular-genetic analysis of mitochondrial DNA associated with chronic progressive external ophthalmoplegia (CPEO) and raged red fibers (RRFs). PATIENTS AND METHOD: Two patients, a male and a female (32 and 28 year-old, respectively), were studied due to progressive palpebral ptosis associated with RRFs in muscle biopsy. Both patients were subjected to neurological, histochemical and enzymatic analysis of muscular biopsy, analysis of cerebro-spinal fluid, and molecular analysis of mitochondrial DNA. RESULTS: Symptoms started at ages 24 and 17 years. Initial symptoms were palpebral ptosis, progressive limitation of vertical and horizontal gaze, fatigue and exercise intolerance, and weakness of proximal muscles. Brain MRIs were normal in both patients. Both patients had deletions of muscle mitochondrial DNA with similar size (5,425 and 5,112 base pairs) and location. CONCLUSIONS: CPEO with RRFs is usually associated with huge deletions in mitochondrial DNA. Fatigue and proximal muscle weakness can be found during the follow-up.

Adverse effects of members of the Enterobacteriaceae family on boar sperm quality.

Semen samples collected in 2012 from 1785 boars belonging to five different breeds were recruited from the quality control laboratory of Magapor SL, Spain. These samples came from 43 boar studs and resulted from diluting the ejaculates in commercial semen extenders. Evaluation of the semen sample characteristics (color, smell, pH, osmolality, concentration, motility of sperm cells, agglutination, acrosome integrity, short hypoosmotic swelling test, and abnormal forms) revealed that they met the international standards. The samples were also tested for the presence of aerobic bacterial contamination. In the present study, 14.73% (n = 263) of the semen samples were contaminated above 3 × 10(2) colony-forming units/mL with at least one type of bacteria. The Enterobacteriaceae family was by far the major contaminant, being present in 40.68% of the contaminated samples (n = 107). Bacterial strains of the Enterobacteriaceae family isolated from boar semen samples were in order of incidence (percentage of the contaminated samples): Serratia marcescens (12.55%), Klebsiella oxytoca (11.79%), Providencia stuartii (9.12%), Morganella morganii (3.80%), Proteus mirabilis (1.90%), and Escherichia coli (1.52%). We have seen that the presence in semen samples of S. marcescens, K. oxytoca, M. morganii, or P. mirabilis, but not P. stuartii or E. coli, was negatively associated with sperm motility (P < 0.05). The mean sperm concentration (P < 0.05), the mean percentage of spermatozoa with curled tails after the short hypoosmotic swelling test (P < 0.01), and the incidence of morphologically normal acrosomes (P < 0.05) were also lower in semen samples infected with M. morganii compared with uninfected ones. Moreover, P. mirabilis was negatively associated with the presence of abnormal forms. Thus, on the basis of the pathological effects that some of these strains may have on boar sperm quality, bacterial contamination should always be examined in semen samples prepared for artificial insemination.

Human mitochondrial haplogroup H: the highest VO2max consumer--is it a paradox?

Mitochondrial background has been demonstrated to influence maximal oxygen uptake (VO(2max), in mLkg(-1)min(-1)), but this genetic influence can be compensated for by regular exercise. A positive correlation among electron transport chain (ETC) coupling, ATP and reactive oxygen species (ROS) production has been established, and mitochondrial variants have been reported to show differences in their ETC performance. In this study, we examined in detail the VO(2max) differences found among mitochondrial haplogroups. We recruited 81 healthy male Spanish Caucasian individuals and determined their mitochondrial haplogroup. Their VO(2max) was determined using incremental cycling exercise (ICE). VO(2max) was lower in J than in non-J haplogroup individuals (P=0.04). The H haplogroup was responsible for this difference (VO(2max); J vs. H; P=0.008) and this group also had significantly higher mitochondrial oxidative damage (mtOD) than the J haplogroup (P=0.04). In agreement with these results, VO(2max) and mtOD were positively correlated (P=0.01). Given that ROS production is the major contributor to mtOD and consumes four times more oxygen per electron than the ETC, our results strongly suggest that ROS production is responsible for the higher VO(2max) found in the H variant. These findings not only contribute to a better understanding of the mechanisms underneath VO(2max), but also help to explain some reported associations between mitochondrial haplogroups and mtOD with longevity, sperm motility, premature aging and susceptibility to different pathologies.

Steady exercise removes VO(2max) difference between mitochondrial genomic variants.

It has been clearly established that mitochondrial variants, among other potential factors, influence on VO(2max). With this study we sought to determine whether this genetic predisposition could be modified by steady exercise. Mitochondrial genetic variants were determined in 70 healthy controls (CON) and in 77 athletes who trained regularly (50 cyclists, aerobic training (AER), and 27 runners of 400m, anaerobic training (NoAER)). All of them were male Spanish Caucasian individuals. A maximum graded exercise test (GXT) in cycle-ergometer was performed to determine VO(2max) (mL kg(-1)min(-1)). Our results confirmed that, in CON, VO(2max) (P=0.007) was higher in Non-J than J individuals. Furthermore, we found that AER and NoAER showed, as it could be expected, higher VO(2max) than CON, but not differences between mitochondrial variants have been found. According with these findings, the influence of mitochondrial DNA (mtDNA) variants on VO(2max) has been confirmed, and a new conclusion has arisen: the steady exercise is able to remove this influence. The interest of these promising findings in muscular performance should be further explored, in particular, the understanding of potential applications in sport training and in muscle pathological syndromes.