Effects of inhibition of the renin-angiotensin system on hypertension-induced target organ damage: clinical and experimental evidence

From Structural to Functional Hypertension Mediated Target Organ Damage—A Long Way to Heart Failure with Preserved Ejection Fraction

Arterial hypertension (AH) is a major risk factor for the development of heart failure (HF) which represents one of the leading causes of mortality and morbidity worldwide. The chronic hemodynamic overload induced by AH is responsible for different types of functional and morphological adaptation of the cardiovascular system, defined as hypertensive mediated target organ damage (HMOD), whose identification is of fundamental importance for diagnostic and prognostic purposes. Among HMODs, left ventricular hypertrophy (LVH), coronary microvascular dysfunction (CMVD), and subclinical systolic dysfunction have been shown to play a role in the pathogenesis of HF and represent promising therapeutic targets. Furthermore, LVH represents a strong predictor of cardiovascular events in hypertensive patients, influencing per se the development of CMVD and systolic dysfunction. Clinical evidence suggests considering LVH as a diagnostic marker for HF with preserved ejection fraction (HFpEF). Several studies have also shown that microalbuminuria, a parameter of abnormal renal function, is implicated in the development of HFpEF and in predicting the prognosis of patients with HF. The present review highlights recent evidence on the main HMOD, focusing in particular on LVH, CMD, subclinical systolic dysfunction, and microalbuminuria leading to HFpEF.

Insulin Resistance and Vitamin D Deficiency: A Link Beyond the Appearances

Vitamin D is a steroid hormone that plays a key role in the regulation of body homeostasis, including cardiovascular function. Although the chronic deficiency of vitamin D is associated with cardiovascular risk factors, as well as with an adverse prognosis, randomized controlled trials have failed in demonstrating that dietary vitamin D supplementation could ameliorate the prognosis of patients with cardiovascular diseases, and suggested that vitamin D deficiency is the expression of the effects of other determinants of cardiovascular risk. Thus, the supplementation of vitamin D is not sufficient to improve the cardiovascular risk profile and prognosis. Insulin resistance is a complex phenomenon that plays a key role in the pathogenesis of conventional cardiovascular risk factors. Interestingly, defects of vitamin D and insulin resistance have a superimposable epidemiological distribution. According to the common view, Insulin resistance is considered the direct or indirect consequence of vitamin D deficiency. However, it is also reasonable to speculate that the deficit or the impaired action of vitamin D, in some circumstances, could be the result of the same pathogenic mechanisms responsible of insulin resistance development. In this case, vitamin D deficiency could be considered an epiphenomenon of insulin resistance. Insulin resistance is a reversible condition, being possibly ameliorated by physical activity and hypocaloric diets. Notably, both physical exercise and energy-restricted dietary regimens are associated with an increase of vitamin D levels. These findings indicate that improving insulin resistance condition is a necessary step to ameliorate vitamin D supplementation-based strategies in cardiovascular prevention.

Molecular Interactions of Arterial Hypertension in Its Target Organs

Arterial hypertension (AH) is a major risk factor for the development of cardiovascular diseases. It is estimated that the disease affects between 10% and 20% of the adult population and is responsible for 5.8% of all deaths worldwide. Several pathophysiologic factors are crucial in AH, including inappropriate activation of the renin-angiotensin-aldosterone system, oxidative stress and inflammation. The heart, kidney, brain, retina and arterial blood vessels are prime targets of hypertensive damage. Uncontrolled and untreated AH accelerates the damage to these organs and could cause their failure. Damage to these organs could also manifest as coronary heart disease, cognitive impairment, retinopathy or optic neuropathy. For better understanding, it is important to analyze molecular factors which take part in pathogenesis of AH and hypertension-related target organ damage. In our paper, we would like to focus on molecular interactions of AH in the heart, blood vessels, brain and kidneys. We focus on matrix metalloproteinases, the role of immune system, the renin-angiotensin-aldosterone system and oxidative stress in hypertensive induced organ damage.