Genetic determinants of 5-lipoxygenase pathway in a Spanish population and their relationship with cardiovascular risk

ObjectiveLeukotrienes (LT) play a role in inflammation, cardiovascular diseases, and cancer. Although some studies suggest that there are genes that determine variability of some LT-related phenotypes, the genetic influence on these phenotypes has not been evaluated.MethodsThe relative contributions of genetic and environmental influences to the 5-lipoxygenase pathway-related phenotypes (5-Lipoxygenase, five lipoxygenase activating protein (FLAP), LTA₄-hydrolase and LTC₄-synthase expression, and LTB₄-plasma concentration and LTB₄ production by stimulated whole blood) were assessed in a sample of 934 individuals in 35 extended families. Our design is based on extended families recruited through a probands with idiopathic thrombophilia. This strategy allows us the analysis of the effects of measured covariates (such as sex, age and smoking), genes, and environmental variables shared by members of a household.ResultsAll of these phenotypes showed significant genetic contributions, with heritabilities ranging from 0.33 to 0.51 for enzyme expression and from 0.25 to 0.50 for LTB₄ production of the residual phenotypic variance. Significant phenotypic and genetic correlation among the LT-related traits was found. More importantly, FLAP and LTA₄-hydrolase expression exhibit significant genetic correlations with arterial thrombosis, indicating that some of the genes that influence quantitative variation in these phenotypes also influence the risk of thrombosis.ConclusionThis is the first study that quantifies the genetic component of 5-Lipoxygenase pathway phenotypes. The high heritability of these traits and the significant genetic correlations between arterial thrombosis and some of these phenotypes suggest that the exploitation of correlated quantitative phenotypes will aid the search for susceptibility genes.     

Individual and summed effects of high-risk genetic polymorphisms on recurrent cardiovascular events following ischemic heart disease

AimsHigh-risk single nucleotide polymorphisms (SNPs) have been recently identified as risk factors for ischemic heart disease in large epidemiological and genome-wide association studies. However, their influence on prognosis remains uncertain. The aim of the study was to investigate the impact of previously identified SNPs and their joint effects in a genetic score (GS) on Major Adverse Cardiac Events (MACEs).Methods and resultsHigh-throughput genotyping for 48 high-risk SNPs was performed in 498 patients (432 males; 57.4 ± 8.3 years) who were followed-up for 6.9 ± 3.4 years. First MACE-coronary-related death, nonfatal myocardial infarction, or myocardial revascularization- was the endpoint taken into consideration. A GS was obtained by summing the number of significant high-risk alleles associated to MACEs.One-hundred and nineteen patients (24%) had a MACE. The hazard ratio (HR) for SNPs with a significant difference in cumulative survival were: APOC3 -482C > T (HR = 1.7, 95% CI 1.01–3.0), MTHFR (HR = 1.5, 95% CI 1.02–2.2), NADHPH oxidase- p22-PHOX C242T (HR = 1.9, 95% CI 1.2–2.8), PON-2 (HR = 0.2, 95% CI 0.1–0.8), and SELP (HR = 0.6, 95% CI 0.4–0.8). The resulting GS predicted a 25% risk for MACEs per risk allele (HR = 1.25, 95% CI 1.1–1.4, p = 0.001). The highest HR for MACEs was found in patients in the top tertile (HR = 3.0, 95% CI 1.4–6.7, p = 0.0005) of the GS compared with those in the bottom tertile.ConclusionOur findings show that high-risk SNPs may be used to create a useful GS that predicts MACEs in a secondary prevention setting, which in turn allows a better risk stratification.     

Asymmetric segregation and self-renewal of hematopoietic stem and progenitor cells with endocytic Ap2a2

The stem cell-intrinsic model of self-renewal via asymmetric cell division (ACD) posits that fate determinants be partitioned unequally between daughter cells to either activate or suppress the stemness state. ACD is a purported mechanism by which hematopoietic stem cells (HSCs) self-renew, but definitive evidence for this cellular process remains open to conjecture. To address this issue, we chose 73 candidate genes that function within the cell polarity network to identify potential determinants that may concomitantly alter HSC fate while also exhibiting asymmetric segregation at cell division. Initial gene-expression profiles of polarity candidates showed high and differential expression in both HSCs and leukemia stem cells. Altered HSC fate was assessed by our established in vitro to in vivo screen on a subcohort of candidate polarity genes, which revealed 6 novel positive regulators of HSC function: Ap2a2, Gpsm2, Tmod1, Kif3a, Racgap1, and Ccnb1. Interestingly, live-cell videomicroscopy of the endocytic protein AP2A2 shows instances of asymmetric segregation during HSC/progenitor cell cytokinesis. These results contribute further evidence that ACD is functional in HSC self-renewal, suggest a role for Ap2a2 in HSC activity, and provide a unique opportunity to prospectively analyze progeny from HSC asymmetric divisions.     

Trace element status and fatty acids metabolism during healthy ageing: an example of a population from the Tunisian eastern coast

Micronutrients as well as essential fatty acids are indispensable for the correct functioning of the organism. The risk of disturbance in the associated nutrition and metabolism is expected to increase during ageing. In addition, it seems that trace elements are involved in the fatty acids metabolism. The aim of the present study was then to assess age-related changes in trace elements status and in plasma essential fatty acids composition with an emphasis on the desaturase activity estimation. Two hundred healthy Tunisian subjects (30-85 years old) were recruited and separated into two subgroups: elderly (65-85 years old) and middle-aged (30-60 years old). The findings revealed that plasma zinc and calcium concentrations significantly decreased according to age. The prevalence of zinc deficiency was therefore shown to increase in old age (over 60% of elderly subjects were deficient or at risk of deficiency). No age-related changes were obtained for copper or magnesium status. The Δ6 desaturase, involved in the EFAs conversion, was shown to decrease according to age and to be associated with the plasma zinc level. Since elderly subjects were at risk of nutritional imbalance, it would be interesting to set optimal dietary proportion. This will help to prevent age-associated alterations and diseases for a better and healthy ageing.     

Genetic and environmental influences on total plasma homocysteine and its role in coronary artery disease risk

BackgroundElevated levels of total plasma homocysteine are a risk factor for atherosclerotic disease.AimsThe rationale behind this study is to explore the correlation between degree and site of coronary lesion and hyperhomocysteinemia in Lebanese CAD patients and assess environmental and genetic factors for elevated levels of total plasma homocysteine.MethodsA total of 2644 patients were analyzed for traditional CAD risk factors. Logistic regression was performed to determine the association of hyperhomocysteinemia with degree and site of coronary lesions controlling for risk factors. Environmental and genetic factors for hyperhomocysteinemia were analyzed by logistic regression using a candidate gene approach.ResultsTraditional risk factors were correlated with stenosis. Hyperhomocysteinemia associated with increased risk of overall stenosis, and risk of mild and severe occlusion in major arteries. Hyperhomocysteinemia and hypertension were highly correlated suggesting that hyperhomocysteinemia acts as a hypertensive agent leading to CAD. Diuretics and genetic polymorphisms in MTHFR and SLCO1B1 were associated with hyperhomocysteinemia.ConclusionsHyperhomocysteinemia is a medical indicator of specific vessel stenosis in the Lebanese population. Hypertension is a major link between hyperhomocysteinemia and CAD occurrence. Genetic polymorphisms and diuretics’ intake explain partly elevated homocysteine levels. This study has important implications in CAD risk prediction.     

Objectively-measured and self-reported physical activity and fitness in relation to inflammatory markers in European adolescents: the HELENA Study

ObjectiveAtherogenesis involves an inflammatory process that occurs early in life even though clinical symptoms are not observed until adulthood. Two important protective factors for low-grade inflammation may be physical activity (PA) and fitness. We examined the independent associations of objective and subjective measurements of PA and fitness with low-grade inflammation in European adolescents.MethodsA total of 1045 adolescents, aged from 12.5 to 17.5 years old from 10 European cities, were selected from the HELENA-Cross-Sectional Study. Objectively-measured and self-reported PA variables were obtained by accelerometry and the International PA Questionnaire for Adolescents, respectively. Overall, cardiorespiratory, muscular and motor fitness variables were assessed by standardized field-based fitness tests and the International Fitness Scale. C-reactive protein (CRP), complement factors 3 (C3) and 4 (C4), interleukin-6 and TNF-α inflammatory markers were measured.ResultsObjectively-measured vigorous PA was inversely associated with C3 (β = ?0.094, P = 0.021) but it did not remain significant after any objective fitness indicator was included in the model. Other objectively measured or self-reported assessments of PA were not significantly associated with inflammatory markers. All objective measures of fitness were inversely associated with CRP, C3 and C4, whereas only self-reported motor fitness remained significantly associated with C3, C4 and TNF-α. All these observations were independent of age, sex, city and body mass index or waist circumference.ConclusionHigh PA in adolescence may play an indirect role on lessening low-grade inflammation through improvements in fitness.     

Prevalence of hepatitis A, B and C serological markers in children from western Mexico

Introduction. Viral hepatitis in children is a major public health problem worldwide.Aim. To evaluate the prevalence of serological markers for hepatitis A, B and C infections in Mexican children diagnosed with hepatitis during a five-year period.Material and methods. A total of 31,818 children admitted to a tertiary level hospital in Mexico from 2005 to 2009 were evaluated for hepatitis.Results. Hepatitis was found in 215 (0.7%) of the children. Serum samples from hepatitis-positive children were screened for anti-HAV IgM, HBsAg, total anti-HBc and anti-HCV. HAV was the leading cause of viral hepatitis (81%), followed by HBV and HCV (3.1 and 2%, respectively), whereas no serological marker was observed in 13.9% of the analyzed samples. Furthermore, when children were categorized by age, a significant increase in anti-HAV detection was observed in school-aged children (7-11 years old) (p < 0.001) and a reduction in adolescents (12-15 years old).Conclusion. In conclusion, hepatitis A is the most prevalent viral hepatitis infection detected in children, followed by HBV and HCV. In addition, the high percentage of hepatitis infections without a known etiological agent and the serological test limitations require the detection of occult HBV, HCV and hepatitis E infections. The age-dependent vulnerability of groups with HAV infections emphasizes the importance of HAV vaccination in young children in Mexico.     

Cuff width influence on blood pressure measurement during the pregnant-puerperal cycle

BACKGROUND: The correct evaluation of blood pressure (BP) during pregnancy is a crucial factor in the prevention of eclampsia. Following American Heart Association (AHA) guidelines to employ a correct cuff width (CCW), 20% larger than arm diameter, we demonstrate that the standard cuff width (SCW), 12 cm wide, is too large for lean women causing underestimation of BP. AIMS: To identify the arm circumference (AC) in pregnant women and the corresponding cuff width; to compare BP records from CCW vs. SCW; and to identify under- and overestimation of BP in SCW reading. DESIGN: A follow up study of BP was performed in 104 pregnant women using two cuffs widths (CCW vs. standard one). The investigation was carried out during all antenatal appointments and postpartum stage in two maternity hospitals. In every appointment BP was registered three times with each type of cuff; and the means of those three readings were compared. METHODS: The CCW for each woman was selected according to AHA recommendation for cuff width size (20% larger than arm diameter), which was based on the classical European and North-American studies. Results. Arm circumference varied from 20 to 38 cm requiring a cuff width from 8 to 14 cm. The CCW most employed was 10 cm wide. The SCW (12 cm) was employed as CCW in only 13.4% of the subjects. Statistical difference was found on BP means when comparing both cuffs (P < 0.05), reaching 23 mmHg in systolic values and 20 in diastolic ones. Such differences showed a serious underestimation when SCW was employed in 80.8% of the subjects and overestimation in 5.8% of obese subjects. CONCLUSION: Our findings showed that the SCW underestimates BP of pregnant women. Our hypothesis is that such underestimation may lead to the misdiagnosis of pre-eclampsia, particularly in lean pregnant women.