Increased ROS production and DNA damage in monocytes are biomarkers of aging and atherosclerosis

BACKGROUND: New evidence demonstrates that aging and dyslipidemia are closely associated with oxidative stress, DNA damage and apoptosis in some cells and extravascular tissues. However, in monocytes, which are naturally involved in progression and/or resolution of plaque in atherosclerosis, this concurrence has not yet been fully investigated. In this study, we evaluated the influence of aging and hypercholesterolemia on serum pro-inflammatory cytokines, oxidative stress, DNA damage and apoptosis in monocytes from apolipoprotein E-deficient (apoE-/-) mice compared with age-matched wild-type C57BL/6 (WT) mice. Experiments were performed in young (2-months) and in old (18-months) male wild-type (WT) and apoE-/- mice. RESULTS: Besides the expected differences in serum lipid profile and plaque formation, we observed that atherosclerotic mice exhibited a significant increase in monocytosis and in serum levels of pro-inflammatory cytokines compared to WT mice. Moreover, it was observed that the overproduction of ROS, led to an increased DNA fragmentation and, consequently, apoptosis in monocytes from normocholesterolemic old mice, which was aggravated in age-matched atherosclerotic mice. CONCLUSIONS: In this study, we demonstrate that a pro-inflammatory systemic status is associated with an impairment of functionality of monocytes during aging and that these parameters are fundamental extra-arterial contributors to the aggravation of atherosclerosis. The present data open new avenues for the development of future strategies with the purpose of treating atherosclerosis.

Triterpenes from the Protium heptaphyllum resin - chemical composition and cytotoxicity

Protium heptaphyllum (Aubl) Marchand, Burseraceae, is popularly used as an analgesic and anti-inflammatory agent. However, the cellular mechanism of action remains unknown. This study aims to evaluate the chemical composition of P. heptaphyllum resin and cytotoxicity on a breast cancer cell line (MCF-7). The chemical composition of the resin was determined by Gas Chromatography coupled to a Mass Spectrometer. The cytotoxicity was evaluated using an MTT assay. Annexin V-FITC, caspase-3, Angiotensin Converting Enzyme activity and Tumor Necrosis Factor alpha (TNF- α) assays were performed to evaluate apoptosis and inflammatory events. The resin consisted of triterpenes, such as α- and β-amyrin. Cytotoxicity was only observed in fractions enriched with α- and β-amyrin. The resin and fractions elicited antiproliferative activity, increased activity of caspase-3 and ACE, and a decrease in the TNF-α level. Altogether, the resin and fractions enriched with α- and β-amyrin promoted cytotoxicity and apoptosis.

Manipulaçäo da expressäo gênica para o entendimento e tratamento de doenças cardiovasculares / Manipulation of gene expression for the under-standing and treatment of cardiovascular diseases

O recente anúncio do sucesso do projeto Genoma Humano constitui-se num grande estímulo para os estudos que visam utilizar a transferência de genes com fins terapêuticos clínicos. Devido ao crescente acúmulo de conhecimento sobre técnicas de biologia molecular e de como manipular a expressäo dos genes, os pesquisadores também desenvolveram estratégias para a transferência de genes, com as quais esperamos que num futuro próximo possamos corrigir, prevenir e tratar as doenças do ser humano. Os sistemas de transferência de genes baseiam-se no uso de diferentes vetores virais transformados em replicantes-deficientes (tais como o adenovírus, o vírus adeno-associado, o retrovírus e o vírus herpes simples) e vetores näo-virais (tais como oligonucleotídeos antisense, DNA de plasmídio e lipossomos), os quais vêm sendo estudados durante os últimos dez anos em fisiologia e testados na clínica. Atualmente também estäo disponíveis muitos animais transgênicos, os quais um gene específico foi adicionado (ratos e camundongos) ou retirado (camundongos knock-out). Esses animais podem ser usados como modelos de estudo para as diferentes fisiopatologias do ser humano, tais como: insuficiência cardíaca, hipertensäo arterial e aterosclerose. Além disso, a estratégia de transferência de genes através de vetores adenovirais pode ser associada com a tecnologia de animais transgênicos para estudar a eficácia da terapia gênica no tratamento de diversas doenças genéticas.

Avaliação do reflexo Bezold-Jarisch no infarto experimental do miocárdio / Evaluation of the Bezold-Jarisch Reflex in Experimental Myocardial Infarction

PURPOSE--To evaluate the cardiogenic depressor Bezold-Jarisch reflex in rats with chronic myocardial infarction. METHODS--Adult Wistar rats were submitted to ligation of the anterior descending coronary artery of the left ventricle (group INF, n = 15) and compared with rats submitted to sham-operation (group Sham, n = 15). Thirty days after the surgery, without influence of anesthetics, the basal mean arterial pressure (MAP) and heart rate (HR) were measured. Immediately after, the Bezold-Jarisch reflex was evaluated measuring the falls in diastolic arterial pressure (DAP) and the simultaneous bradycardia induced by injections of 5-hydroxytryptamine (5-HT, 4 to 32 micrograms/kg, i.v.). RESULTS--The INF group showed significantly lower basal MAP and HR values (103 +/- 3 mmHg and 328 +/- 6 bpm) when compared to the Sham group (110 +/- 2 mmHg and 348 +/- 7 bpm). The Bezold-Jarisch reflex was significantly attenuated in the INF group (falls of DAP from 2 +/- 2 to 31 +/- 3 mmHg and HR from 8 +/- 5 to 204 +/- 15 bpm), when compared to the Sham group (falls of DAP from 10 +/- 3 to 41 +/- 3 mmHg and HR from 58 +/- 12 to 276 +/- 16 bpm). The morphological analysis showed a myocardial infarction mainly located at the anterolateral portion of the left ventricle with a maximal extension of 35 of the left ventricle circumference. The INF group showed right ventricular and left atrial hypertrophy when compared to the Sham group. CONCLUSION--The experimental chronic myocardial infarction in rats is followed by significant attenuation of the Bezold-Jarisch reflex, probably as result of a heart failure and, consequently, of functional alterations in the chemosensitive receptors of cardiac unmyelinated vagal afferents.