Domenech Raúl J, Macho Pilar
Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile.
Rev Med Chil. 2008 Dec;136(12):1582-8. Epub 2009 Mar 23.
Aging produces its own cardiovascular changes, mainly remodelling of arteries, heart and the microcirculation. These progressive changes, detected since adolescence, represent a major risk factor for the development of cardiovascular diseases. Remodelling of arteries produces a thickening of the intima-media with fracture of elastic fibers and their replacement by collagen. These alterations induce an increase of the pulse wave and aortic impedance, with greater resistance to ventricular ejection, that in turns induces the remodelling of the left ventricle. Ventricular remodelling leads to systolic, diastolic and chronotropic dysfunctions that explain the reduced capacity of old people to increase cardiac output during exercise. These alterations together with oxidative endothelial dysfunction and somatic mitochondrial mutations in the skeletal muscle decrease aerobic capacity, especially in adults aged >70 years. On the other hand, the transmission of an increased pulse wave to microvessels, mainly of the brain and kidneys, damage these organs. There is a search for candidate genes associated to this phenotype, especially those associated with arterial structure. At present no specific treatment is available for cardiovascular aging. Exercise preserves a better aerobic capacity but does not prevent its decline with age. Vasodilator drugs may decrease aortic impedance and perhaps delay remodelling. However there is no clinical evidence available to recommend these drugs in young healthy people. Finally new drugs that modify aortic molecular structure are been investigated.
衰老会引发自身的心血管变化,主要包括动脉、心脏和微循环的重塑。这些自青春期起就被检测到的渐进性变化,是心血管疾病发展的主要危险因素。动脉重塑会导致内膜中层增厚,弹性纤维断裂并被胶原蛋白取代。这些改变会导致脉搏波和主动脉阻抗增加,对心室射血的阻力增大,进而引发左心室重塑。心室重塑会导致收缩、舒张和变时性功能障碍,这解释了老年人在运动时增加心输出量的能力下降的原因。这些改变连同氧化内皮功能障碍和骨骼肌中的体细胞线粒体突变会降低有氧能力,尤其是在70岁以上的成年人中。另一方面,增加的脉搏波传递到微血管,主要是大脑和肾脏的微血管,会损害这些器官。目前正在寻找与这种表型相关的候选基因,尤其是那些与动脉结构相关的基因。目前尚无针对心血管衰老的特效治疗方法。运动能保持较好的有氧能力,但无法阻止其随年龄下降。血管扩张药物可能会降低主动脉阻抗,或许还能延缓重塑。然而,尚无临床证据支持在年轻健康人群中推荐使用这些药物。最后,正在研究能改变主动脉分子结构的新药。