Influence of vascular load on plasma endothelin-1, cytokines and catecholamine levels in essential hypertensives

Strength training for arterial hypertension treatment: a systematic review and meta-analysis of randomized clinical trials

Cardiovascular diseases are the leading cause of death in the world and arterial hypertension (AH) accounts for 13.8% of deaths caused by cardiovascular diseases. Strength training interventions could be an important alternative tool for blood pressure control, however, consistent evidence and the most effective training protocol for this purpose are yet to be established. The current study used the Cochrane methodology to systematically review randomized controlled trials (RCTs) that investigated the effect of strength training on blood pressure in hypertensive patients. A systematic search was conducted in the PubMed, EMBASE, Scopus, Cochrane Library, and World Health Organization databases. This review included controlled trials that evaluated the effect of strength training for 8 weeks or more in adults with arterial hypertension, published up to December 2020. Data are described and reported as the weighted mean difference of systolic and diastolic pressure and a 95% confidence interval. Protocol registration: PROSPERO registration number CRD42020151269. A total of 14 studies were identified, including a combined total of 253 participants with hypertension. The meta-analysis showed that mean values of systolic blood pressure (SBP) and diastolic blood pressure (DBP) decreased significantly after strength training interventions. The strongest effect of strength training on decreasing blood pressure was observed in protocols with a moderate to vigorous load intensity (> 60% of one-repetition maximum-1RM), a frequency of at least 2 times per week, and a minimum duration of 8 weeks. We concluded that strength training interventions can be used as a non-drug treatment for arterial hypertension, as they promote significant decreases in blood pressure.

Cardiovascular and hormonal responses to static handgrip in young and older healthy men

The purpose of this study was to investigate the effect of age on cardiovascular changes and plasma concentrations of adrenomedullin (ADM), catecholamines, endothelin-1 (ET-1) and plasma renin activity (PRA) in healthy men. A total of 15 young (21 ± 0.3 years) and 15 older (64 ± 0.7 years) healthy men performed two 3-min bouts of static handgrip at 30% of maximal voluntary contraction, alternately with each hand without any break between the bouts. During exercise heart rate (HR), blood pressure (BP), stroke volume (SV) and pre-ejection period (PEP) and left ventricle ejection time (LVET) were measured. Blood samples were taken before exercise, at the end of both exercise bouts and in the fifth minute of the recovery period. The handgrip-induced increases in HR and cardiac output were significantly smaller in older than in young men (p < 0.01). SV decreased only in older men (p < 0.001). There were no differences between groups in BP increases. The baseline plasma ADM and catecholamines were higher in older man compared to young subjects. Handgrip caused increases in plasma ADM, ET-1 and PRA only in older men (p < 0.05). The increases in plasma ADM correlated positively with those of noradrenaline (NA), PRA, ET-1 and LVET and negatively with changes in total peripheral resistance (TPR), SV, PEP and PEP/LVET ratio. The increases in plasma ET-1 correlated positively with those of NA, PRA, TPR, mean BP and SV. These results revealed that ADM, ET-1 and angiotensin II can contribute to maintain vascular tone during static exercise in older but not in younger men.

Endogenous endothelin-1 limits exercise-induced vasodilation in hypertensive humans

Essential hypertension is a common disorder, associated with increased endothelin-1-mediated vasoconstrictor tone at rest. We hypothesized that increased vasoconstrictor activity of endothelin-1 might explain why the normal decrease in peripheral vascular resistance in response to exercise is attenuated in hypertensive patients. Therefore, we investigated the effect of endothelin A (ET(A)) receptor blockade on the vasodilator response to handgrip exercise. Forearm blood flow responses to handgrip exercise (15%, 30%, and 45% of maximum voluntary contraction) were assessed in hypertensive patients and matched normotensive subjects, before and after intra-arterial infusions of the ET(A) receptor antagonist BQ-123; a control dilator, hydralazine; and placebo (saline). Preinfusion (baseline) vasodilation in response to exercise was significantly attenuated at each workload in hypertensive patients compared with normotensive subjects. Intra-arterial infusions of hydralazine and saline did not increase the vasodilator response to exercise in either hypertensives or normotensives at any workload. The vasodilator response to exercise was markedly enhanced after BQ-123 at the 2 higher workloads in hypertensives (157+/-48%, P<0.01; 203+/-58%, P<0.01) but not in normotensives. This suggests that the impaired vasodilator response to exercise in hypertensive patients is, at least in part, a functional limitation caused by endogenous ET(A) receptor-mediated vasoconstriction. Treatment with endothelin receptor antagonists may, therefore, increase exercise capacity in essential hypertension.

Endothelium-derived factors in microalbuminuric and nonmicroalbuminuric essential hypertensives

Previous evidence has demonstrated a relationship between growth factors and cardiovascular diseases. This study was aimed at evaluating levels of some endothelium-derived growth factors, and their relationship with microalbuminuria (MAU), in essential hypertension. Ninety-nine mild-moderate essential hypertensives (EH) and 25 healthy controls were studied. All patients underwent 24-h blood pressure monitoring, serum endothelin-1 (ET-1), basic fibroblast growth factor (bFGF) and platelet-derived growth factor (PDGF), and 24-h MAU assays. Later, EH were divided into two subsets consisting of microalbuminurics (MAU >11 microg/min) and nonmicroalbuminurics (MAU <11 microg/min). In microalbuminuric EH, circulating ET-1, bFGF, and PDGF were significantly higher than in nonmicroalbuminurics (P < .0001, P < .0001, P < .005, respectively) or in controls. In the group of 99 EH, significant positive correlations of MAU with both ET-1 and bFGF (r = 0.35, P < .001, and r = 0.34, P < .001, respectively) were found. ET-1 and bFGF correlated significantly (r = 0.31, P < .002). Circulating bFGF also correlated significantly with MAU in the microalbuminuric EH subset (r = 0.49, P < .01). Our results show that in microalbuminuric EH circulating levels of certain growth factors are increased. In human essential hypertension these factors are linked with MAU, an early cardiovascular and renal damage marker.

Stimulation of neonatal and adult brain neurogenesis by subcutaneous injection of basic fibroblast growth factor

Mounting evidence indicates that extracellular factors exert proliferative effects on neurogenetic precursors in vivo. Recently we found that systemic levels of basic fibroblast growth factor (bFGF) regulate neurogenesis in the brain of newborn rats, with factors apparently crossing the blood-brain barrier (BBB) to stimulate mitosis. To determine whether peripheral bFGF affects proliferation during adulthood, we focused on regions in which neurogenesis persists into maturity, the hippocampus and the forebrain subventricular zone (SVZ). In postnatal day 1 (P1) rats, 8 hr after subcutaneous injection (5 ng/gm body weight), bFGF increased [(3)H]thymidine incorporation 70% in hippocampal and SVZ homogenates and elicited twofold increases in mitotic nuclei in the dentate gyrus and the dorsolateral SVZ, detected by bromodeoxyuridine immunohistochemistry. Because approximately 25% of proliferating hippocampal cells stimulated in vivo expressed neuronal traits in culture, bFGF-induced mitosis may reflect increased neurogenesis. bFGF effects were not restricted to the perinatal period; hippocampal DNA synthesis was stimulated by peripheral factor in older animals (P7-P21), indicating the persistence of bFGF-responsive cells and activity of peripheral bFGF into late development. To begin defining underlying mechanisms, pharmacokinetic studies were performed in P28 rats; bFGF transferred from plasma to CSF rapidly, levels rising in both compartments in parallel, indicating that peripheral factor crosses the BBB during maturity. Consequently, we tested bFGF in adults; peripheral bFGF increased the number of mitotic nuclei threefold in the SVZ and olfactory tract, regions exhibiting persistent neurogenesis. Our observations suggest that bFGF regulates ongoing neurogenesis via a unique, endocrine-like pathway, potentially coordinating neuron number and body growth, and potentially providing new approaches for treating damaged brain during development and adulthood.