Vascular Aging and Disease of the Small Vessels

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Vascular Aging and Disease of the Small Vessels Damiano Rizzoni1,2   · Marco Rizzoni3 · Matteo Nardin1 · Giulia Chiarini1 · Claudia Agabiti‑Rosei1 · Carlo Aggiusti1 · Anna Paini1 · Massimo Salvetti1 · Maria Lorenza Muiesan1 Received: 5 March 2019 / Accepted: 24 May 2019 / Published online: 29 May 2019 © Italian Society of Hypertension 2019

Abstract Cardiovascular events are the consequence of vascular damage at both the macro and microcirculatory level. The relationship between large stiffening artery and microvascular disease may be bidirectional, since wave reflection from microvascular sites could increase systolic blood pressure and pulse pressure, while transmission of increased arterial pulsatility to microvessels could represent a mechanism of damage. Hypertension and aging share similar mechanisms of vascular dysfunction. In fact, vascular remodelling, endothelial dysfunction and vascular stiffness are common features in hypertension and aging. Structural and functional changes in small arteries occur during normal and accelerated aging, possibly triggered by hypertension. A cross-talk may be present between large and small artery changes, interacting with pressure wave transmission and reflection, exaggerating cardiac, brain and kidney damage, and finally leading to cardiovascular and renal complications. Keywords  Aging · Elderly · Hypertension · Macrocirculation · Microcirculation · Small resistance arteries

1 Introduction Vascular ageing may be triggered by several mechanisms, including oxidative stress, inflammation, proliferation of smooth muscle cells, increased collagen content, etc. [1]. These factors may be involved in specific changes in vascular structure (remodeling) and function that may be observed both in large arteries and in the small vessels. During aging, in large, conductance arteries an increased stiffness, an increased intima media thickness and an increased lumen diameter might be observed [1–3], while in smaller vessels, an increased wall thickness, an increased lumen diameter and an increased wall cross-sectional area are more commonly detected [3, 4]. In the large arteries it was postulated that the presence of hypertension accelerates

* Damiano Rizzoni [email protected] 1



Clinica Medica, Department of Clinical and Experimental Sciences, University of Brescia, c/o 2a Medicina Spedali Civili di Brescia, Piazza Spedali Civili 1, 25100 Brescia, Italy

2



Division of Medicine, Istituto Clinico Città di Brescia, Brescia, Italy

3

Department of Information Engineering, University of Brescia, Brescia, Italy



the vascular effects of aging per se [1]. In fact, the observed increment of 2 m/s in the pulse wave velocity (index of large artery stiffness) between the age groups “50–59 years” and “more than 70 years”, in a large reference population of 11.092 subjects, is anticipated by the presence of hypertension by 10–20 years [5].

2 Aging and the Microcirculation In animal models of aging an outward hypertrophic remodeling, characterized by increased lum