Vascular Hypertrophy and Remodeling in Secondary Hypertension

Abstract

It has been proposed that several neurohumoral factors may be involved in the genesis of vascular structural changes (remodeling or hypertrophy) frequently observed in essential hypertension. Therefore, in this study we investigated vascular structural alterations of subcutaneous small resistance arteries in patients with secondary forms of hypertension. The study included 70 participants: 11 with pheochromocytoma, 13 with primary aldosteronism, and 17 with renovascular hypertension; 13 normotensive subjects and 16 patients with essential hypertension served as controls. All subjects were submitted to a biopsy of subcutaneous fat. Small resistance arteries were dissected and mounted on a micromyograph, and media-lumen ratio, media thickness, remodeling index, and growth index were evaluated. Endothelial function was evaluated according to the dose-response curve to acetylcholine. In patients with either primary aldosteronism or renovascular hypertension, a marked increase in media-lumen ratio was observed, whereas in patients with pheochromocytoma, the extent of vascular structural alterations was similar to that observed in patients with essential hypertension. The increase in media-lumen ratio in patients with essential hypertension and with pheochromocytoma was mainly due to vascular remodeling (remodeling index, 93% to 94%), whereas in patients with renovascular hypertension, there was vascular growth (remodeling index, 70%; growth index, 53%). Patients with primary aldosteronism had an intermediate pattern compared with the other two forms of secondary hypertension. An evident impairment of endothelial function was observed in all four hypertensive groups. In conclusion, the renin-angiotensin-aldosterone system seems to be more powerful than the adrenergic system in inducing vascular growth.

Normalization of catecholamine production following resection of phaeochromocytoma positively influences carotid vascular remodelling

“…This finding has been better documented in patients with abnormal catecholamine tone due to PHEO. Thus, in small resistance arteries of these patients, eutrophic remodelling has been reported, using a micromyographic technique (15)(16)(17). In a recent study, we confirmed these data in conduit arteries (carotid) of patients with PHEO using a non-invasive procedure, such as ultrasonic backscatter signal technique (18).…”

“…In addition, in patients with phaeochromocytoma (PHEO), studies conducted by micromyographic technique on the small resistance arteries have demonstrated that high catecholaminergic tone is associated with eutrophic vascular remodelling (15)(16)(17). Our group recently confirmed that also in conduit arteries (carotid) of patients with PHEO a sustained vascular remodelling with fibrosis may likewise be detected, through the ultrasound and ultrasonic integrated backscatter signal (IBS) technique (18).…”

Prognostic Significance of Small-Artery Structure in Hypertension

“…Details about the micromyographic technique of evaluation of small-artery morphology were reported previously. [12][13][14] Follow-up information was obtained by telephone interviews or by reevaluating subjects in the outpatient clinic. We considered cardiovascular events to be the following conditions: sudden death, ischemic or hemorrhagic stroke, transient cerebral ischemic attack, myocardial infarction, new-onset angina requiring hospitalization, progressive heart failure requiring hospitalization, coronary artery bypass or angioplasty, renal failure requiring dialysis, implantation of a pacemaker device, development of symptomatic lower-limb atherosclerosis, or surgical intervention for aortic aneurisms.…”

“…12,13,15 The presence of structural alterations in subcutaneous and omental small resistance arteries from essential hypertensive patients has been demonstrated with this approach. 6,14,15 The mechanisms leading to vascular remodeling are currently unknown, although it has been suggested that vascular wall stress, neurohormonal environment, and changes in extracellular matrix proteins 16 may have a crucial role.…”

Plasma membrane calcium ATPases (PMCAs) as potential targets for the treatment of essential hypertension

“…There is now significant evidence to support the notion that high BP is associated with a remodelling of resistance arteries such that there is a thickening of the medial layer of the arterial wall of resistance arteries, a reduced lumen diameter and thus an increased media to lumen ratio Martinez-Lemus et al, 2009;Rizzoni & Agabiti-Rosei, 2012;Renna et al, 2013). Although growth may be evident in certain pathologies and in advanced hypertension (Rizzoni et al, 1996), there is now a wealth of evidence to suggest that inward remodelling of resistance arteries with no significant change in cross sectional area, termed eutrophic remodelling, is a key feature of essential hypertension, and underpins elevated peripheral resistance Izzard et al, 2005;Heerkens et al, 2006;Staiculescu et al, 2013). Eutrophic remodelling of resistance arteries is proposed to be a consequence of realignment and potentially closer associations between vascular smooth muscle cells (VSMCs) of the arterial wall, and not hypertrophy and/or hyperplasia of VSMCs, generating a detectable narrowing in lumen diameter of the vessel (Heagerty et al, 2010), Fig.…”