Carotid body Thermoreceptors, sympathetic neural activation, and cardiometabolic disease

The carotid body (CB) is the main peripheral chemoreceptor that senses the arterial PO2, PCO2 and pH. In response to hypoxemia, hypercapnia and acidosis, carotid chemosensory discharge elicits reflex respiratory, autonomic and cardiovascular adjustments. The classical construct considers the CB as the main peripheral oxygen sensor, triggering reflex physiological responses to acute hypoxemia and facilitating the ventilatory acclimation to chronic hypoxemia at high altitude. However, a growing body of experimental evidence supports the novel concept that an abnormally enhanced CB chemosensory input to the brainstem contributes to overactivation of the sympathetic nervous system, and consequent pathology. Indeed, the CB has been implicated in several diseases associated with increases in central sympathetic outflow. These include hypertension, heart failure, sleep apnea, chronic obstructive pulmonary disease and metabolic syndrome. Indeed, ablation of the CB has been proposed for the treatment of severe and resistant hypertension in humans. In this review, we will analyze and discuss new evidence supporting an important role for the CB chemoreceptor in the progression of autonomic and cardiorespiratory alterations induced by heart failure, obstructive sleep apnea, chronic obstructive pulmonary disease and metabolic syndrome.

Cardiovascular consequences of obstructive sleep apnoea.

Obstructive sleep apnoea (OSA) is a form of sleep disordered breathing with a high prevalence rate and is often underdiagnosed. OSA is associated with hypertension, coronary artery disease, stroke, peripheral vascular disease, heart failure, and arrhythmias. The presence of OSA may be a strong predictor of fatal cardiovascular events in patients with cardiovascular disease (CVD). Increased sympathetic drive, activation of metabolic and inflammatory markers, and impaired vascular function are some of the proposed mechanisms that could explain the association between OSA and cardiovascular diseases. Understanding these mechanisms is important for identifying treatment strategies. The presence of OSA should be considered in clinical practice, especially in patients with CVD. Randomized intervention studies are needed to establish whether early identification and treatment of OSA patients reduces cardiovascular morbidity.

Update in prevention of atherosclerotic heart disease: Management of major cardiovascular risk factors / Actualización en la prevención de la enfermedad aterosclerótica: manejo de los principales factores de riesgo

Cardiovascular disease (CVD) remains as the first cause of death worldwide. Scientific community works everyday trying to ameliorate this burden. Only in the year 2004 around 2,790 publications about the therapeutic use of antihypertensive agents can be found in MEDLINE. Despite this overwhelming effort and information, only a relatively short number of manuscripts have a real impact in clinical practice. For the busy clinician, it becomes almost impossible to screen and be updated with the landmark publications. The purpose of this article is to provide concise information related to prevention of CVD. We reviewed publications in the past 5 years regarding cardiovascular risk factors with special attention to dyslipide-mia, hypertension, diabetes, smoking cessation and obesity, discussing some new findings and treatments. We also discuss obstructive sleep apnea (OSA) as a recently identified cardiovascular risk factor, and provide a general overview about its pathophysiology and treatment.

La enfermedad cardiovascular es la primera causa de muerte a nivel mundial. La comunidad científica trabaja diariamente con el fin de atenuar este problema. Sólo en el año 2004 cerca de 2,790 publicaciones acerca del manejo de hipertensión pueden ser encontradas en el servidor electrónico MEDLINE. A pesar de esta gran cantidad de información, sólo un pequeño número de publicaciones tiene impacto en la práctica clínica. Tomando en cuenta el trabajo del clínico hoy en día y la cantidad de material publicado, resulta casi imposible el mantenerse actualizado. El propósito de este artículo es el proveer información concisa y relevante relacionada con la prevención de la enfermedad cardiovascular aterosclerótica. Se revisaron publicaciones relevantes de los últimos cinco años concernientes a los principales factores de riesgo cardiovascular con especial ánfasis en dislipidemia, hipertensión, diabetes, tabaquismo y obesidad. También se discute la apnea obstructiva del sueño, enfermedad descrita recientemente como un factor de riesgo cardiovascular, se comentan de manera general su patofisiología y tratamiento.