Cholesterol efflux capacity does not associate with coronary calcium, plaque vulnerability, and telomere length in healthy octogenarians.

Several studies have revealed that traditional risk factors are less effective in predicting CVD risk in the elderly, suggesting the need to identify new biomarkers. Here, we evaluated the association between serum cholesterol efflux capacity (CEC), an atheroprotective property of HDL recently identified as a novel marker of CVD risk, and atherosclerotic burden in a cohort of very old, healthy individuals. Serum CEC values were not significantly correlated either with calcium score or with markers of vulnerable plaque, such as positive remodeling, hypodensity, spotty calcification, or napking-ring sign. In addition, no association was detected between CEC and telomere length, a marker of biological aging that has been linked to atherosclerosis extent. Interestingly, elderly subjects presented a remarkably higher CEC (+30.2%; P < 0.0001) compared with values obtained from a cohort of sex-matched, cardiovascular event-free, middle-aged individuals. In conclusion, serum CEC is not related to traditional risk factors in very old, cardiovascular event-free subjects, but has significantly higher values compared with a healthy, younger population. Whether this improved HDL functionality may represent a protective factor in CVD onset must be established in future studies.

Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) Inhibitors and Incident Type 2 Diabetes: A Systematic Review and Meta-analysis With Over 96,000 Patient-Years.

OBJECTIVE: Like mutations with loss of function in the proprotein convertase subtilisin/kexin type 9 (PCSK9) gene, inhibitors of PCSK9 (PCSK9i) may potentially favor the manifestation of diabetes. RESEARCH DESIGN AND METHODS: A meta-analysis of phase 2/3 randomized clinical trials (RCTs) assessed PCSK9i versus placebo in the primary hypercholesterolemia setting. Statins and ezetimibe were used in 98.4% of these studies and balanced between PCSK9i and placebo. We calculated relative risks (RRs) and 95% CIs using random- and fixed-effect models. RESULTS: We included 68,123 participants (20 RCTs) with median follow-up of 78 weeks. PCSK9i increased fasting blood glucose (weighted mean difference 1.88 mg/dL [95% CI 0.91-2.68]; I2 = 0%; P < 0.001) and HbA1c (0.032% [0.011-0.050]; I2 = 15.5%; P < 0.001) when compared with placebo. This effect was not sufficient to increase incidence of diabetes (RR 1.04 [0.96-1.13]; I2 = 0%; P = 0.427). Exploratory meta-regression analyses indicated an association between the increased risk of diabetes and the potency (P = 0.029) and duration (P = 0.026) of PCSK9i treatment. CONCLUSIONS: In the short term, PCSK9i therapy favors a small but significant increase in plasma glycemia and HbA1c.

Sarcopenia, but not excess weight or increased caloric intake, is associated with coronary subclinical atherosclerosis in the very elderly.

BACKGROUND AND AIMS: Excess weight is a widespread condition related to increased risk of coronary heart disease (CHD). Sarcopenia is a catabolic pathway common of the aging process and also associated with CHD. In the elderly, both changes occur concurrently and it remains unclear the relative contribution on CHD risk. We aimed to investigate whether sarcopenia, excess weight, or both are associated with subclinical atherosclerosis and/or endothelial dysfunction in very elderly individuals. METHODS: We performed a cross-sectional study of cohort enrolled individuals, aged 80 years or older (n = 208), who had never manifested cardiovascular diseases. Blood tests, medical and nutritional evaluations, cardiac computed tomography, flow-mediated dilation (FMD) and physical performance tests were obtained at the study admission. Odds ratio (OR) was calculated by multivariate regression models using coronary calcium score (CCS) categories and FMD as dependent variables. Adjustment for potential confounders was done. RESULTS: Muscle mass, but not fatty mass, was inversely associated with CCS categories [OR:2.54(1.06-6.06); p = 0.018]. The lowering of gait speed was negatively related to CCS>100 [OR:2.36 (1.10-5.06); p = 0.028] and skeletal muscle index was directly associated with FMD [OR:5.44 (1.22-24.24); p = 0.026]. Total caloric intake was positively related to fatty mass [OR:2.71 (1.09-6.72); p = 0.031], but was not related to CCS. CONCLUSIONS: This study reveals that sarcopenia - comprised by reduction of muscle mass and its strength - is associated with subclinical atherosclerosis and endothelial dysfunction. Surprisingly, the excess of fatty mass seems not to be related to atherosclerotic burden in very elderly individuals.

ST-elevation myocardial infarction risk in the very elderly.

BACKGROUND: Despite the high incidence and mortality of ST-segment elevation myocardial infarction (STEMI) among the very elderly, risk markers for this condition remain poorly defined. This study was designed to identify independent markers of STEMI among individuals carefully selected for being healthy or manifesting STEMI in < 24 h. METHODS: We enrolled participants aged 80 years or older of whom 50 were STEMI patients and 207 had never manifested cardiovascular diseases. Blood tests, medical and psychological evaluations were obtained at study admission. Odds Ratio (OR) and attributed risk (AR) were obtained by multivariate regression models using STEMI as dependent variable. RESULTS: Low glomerular filtration rate (GFR) [OR:4.41 (1.78-10.95); p = 0.001], reduced levels of HDL-C [OR:10.70 (3.88-29.46); p = 0.001], male gender [OR:12.08 (5.82-25.08); p = 0.001], moderate to severe depressive symptoms [OR:10.00 (2.82-35.50); p = 0.001], prior smoking [OR:2.00 (1.05-3.80); p = 0.034] and current smoking [OR:6.58 (1.99-21.70); p = 0.002] were significantly associated with STEMI. No association was found between STEMI and age, diabetes, hypertension, mild depressive symptoms, triglyceride or LDL-C. CONCLUSIONS: This is the first case-control study carried out with very elderlies to assess STEMI risk. Our findings indicate that reduced HDL-C, GFR, male gender, smoking habits and moderate to severe depressive symptoms are markers of STEMI in this age group. GENERAL SIGNIFICANCE: In Individuals aged 80 or more years, a greater attention must be paid to low HDL-C and GFR at the expense of conventional STEMI risk factors for younger adults such as diabetes mellitus, hypertension and high LDL-C or triglyceride.

[Molecular mechanism of thyroid hormone action]. / Mecanismo molecular da ação do hormônio tireoideano.

Thyroid hormones (TH) are involved in normal differentiation, growth, and metabolism in several tissues of all vertebrates. Their actions are mediated by the TH receptors (TRs), members of the nuclear hormone receptor superfamily. These receptors are transcription factors that bind to DNA on specific sequences, the TR response element (TREs), in promoters of target genes. Two genes encode TRs, alpha e beta, located in chromosomes 17 and 3, respectively. These isoforms show different functions and exhibit a tissue specific expression. TRs function as monomers, homodimers or heterodimers with retinoid X receptor (RXR) and modulate transcription activity (repression or activation) by interacting with co-repressor and co-activators, which associate with TR in the absence or presence of T3, respectively. Understanding the molecular mechanism of TR action and the definition of its crystallographic structure will provide new insights into transcription mechanisms and will facilitate the design of new drugs with greater therapeutic value.

Mecanismo molecular da ação do hormônio tireoideano / Molecular mechanism of thyroid hormone action

Os hormônios tireoideanos (HTs) são necessários para a diferenciação, crescimento e metabolismo de diversos tecidos de vertebrados. Seus efeitos são mediados pelos receptores do hormônio tireoideano (TRs), membros da superfamília dos receptores nucleares. Estes receptores são fatores de transcrição modulares que se ligam em seqüências específicas do DNA denominadas elementos responsivos ao TR, que são encontrados nos promotores dos genes regulados pelo HT. Os TRs são codificados por dois genes distintos, alfae beta, localizados nos cromossomos 17 e 3, respectivamente. Estas isoformas apresentam diferentes funções e sua expressão é específica para cada tecido. O TR se liga ao DNA como monômero, homodímero ou heterodímero com o receptor de retinóide X (RXR). Além disso, o TR modula a atividade transcricional (repressão ou ativação) através da interação com correpressores e co-ativadores, na ausência e na presença do T3, respectivamente. A compreensão do mecanismo molecular da ação do receptor do hormônio tireoideano e a definição de sua estrutura cristalográfica contribuirão para a aquisição de novos conceitos envolvidos na transcrição e nos distúrbios hormonais presentes nas doenças endócrinas, assim como facilitará o desenho de novas drogas, agonistas ou antagonistas, com grande valor terapêutico.