Vascular Fibrosis in Aging and Hypertension: Molecular Mechanisms and Clinical Implications.
Aging is the primary risk factor underlying hypertension and incident cardiovascular disease. With aging, the vasculature undergoes structural and functional changes characterized by endothelial dysfunction, wall thickening, reduced distensibility, and arterial stiffening. Vascular stiffness results from fibrosis and extracellular matrix (ECM) remodelling, processes that are associated with aging and are amplified by hypertension. Some recently characterized molecular mechanisms underlying these processes include increased expression and activation of matrix metalloproteinases, activation of transforming growth factor-β1/SMAD signalling, upregulation of galectin-3, and activation of proinflammatory and profibrotic signalling pathways. These events can be induced by vasoactive agents, such as angiotensin II, endothelin-1, and aldosterone, which are increased in the vasculature during aging and hypertension. Complex interplay between the "aging process" and prohypertensive factors results in accelerated vascular remodelling and fibrosis and increased arterial stiffness, which is typically observed in hypertension. Because the vascular phenotype in a young hypertensive individual resembles that of an elderly otherwise healthy individual, the notion of "early" or "premature" vascular aging is now often used to describe hypertension-associated vascular disease. We review the vascular phenotype in aging and hypertension, focusing on arterial stiffness and vascular remodelling. We also highlight the clinical implications of these processes and discuss some novel molecular mechanisms of fibrosis and ECM reorganization.
Institute of Cardiovascular and Medical Sciences, BHF Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, Scotland.
Adam
A
Harvey
Institute of Cardiovascular and Medical Sciences, BHF Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, Scotland.
Augusto C
AC
Montezano
Institute of Cardiovascular and Medical Sciences, BHF Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, Scotland.
Rheure Alves
RA
Lopes
Institute of Cardiovascular and Medical Sciences, BHF Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, Scotland.
Francisco
F
Rios
Institute of Cardiovascular and Medical Sciences, BHF Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, Scotland. Electronic address: rhian.touyz@glasgow.ac.uk.
Rhian M
RM
Touyz
D000375:Aging; D000804:Angiotensin II / Q000378:metabolism; D019332:Endothelin-1 / Q000378:metabolism; D004730:Endothelium, Vascular / Q000473:pathology*; D005355:Fibrosis / Q000473:pathology; D006801:Humans; D006973:Hypertension / Q000473:pathology* / Q000503:physiopathology; D020782:Matrix Metalloproteinases / Q000378:metabolism; D012307:Risk Factors; D051785:Smad Proteins / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000378:metabolism; D059289:Vascular Stiffness
D019332:Endothelin-1; D051785:Smad Proteins; D053773:Transforming Growth Factor beta1; D000804:Angiotensin II; D020782:Matrix Metalloproteinases