Matrix Metalloproteinase-9 and Augmentation Index are Reduced with an 8-Week Green-Exercise Walking Programme
- *Corresponding Author:
- Jane ES Thompson
Centre for Biomedical Sciences
Cardiff School of Health Sciences
Cardiff Metropolitan University
Western Avenue, Cardiff, CF5 2YB, United Kingdom
Tel: +44 (2920) 416457
Fax: +44(2920) 416982
E-mail: [email protected]
Received Date: August 29, 2013; Accepted Date: September 30, 2013; Published Date: October 03, 2013
Citation: Thompson JES, Webb R, Hewlett P, Llewellyn D, Mcdonnell BJ (2013) Matrix Metalloproteinase-9 and Augmentation Index are Reduced with an 8-Week Green-Exercise Walking Programme. J Hypertens 2:127. doi:10.4172/2167-1095.1000127
Copyright: © 2013 Thompson JES, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Objectives: MMP-9 is involved in degrading the Extracellular Matrix (ECM); specifically elastin, which provides elasticity to the arterial wall. Elastin degradation and restructuring of the ECM results in increased vascular remodelling and arterial stiffness. Conversely, exercise improves age-related vascular stiffening. Therefore, this study aimed to investigate whether participation in a green-exercise programme affects vascular haemodynamics and mRNA expression of MMP-9.
Methods: Thirty-six healthy, sedentary individuals (44 ± 2yrs; not taking any cardiovascular-acting medication) joining a moderate-intensity, aerobic green-exercise programme, were recruited. At baseline and 8-weeks into the programme, physical activity (measured in weekly MET-minutes [IPAQ]), supine Mean Arterial Blood Pressure (MAP), Augmentation Index (AIx) and aortic Pulse Wave Velocity (aPWV) data were collected and blood samples were obtained. Leukocytic MMP-9 mRNA expression (RT-PCR) and plasma protein levels (ELISA) were analysed; AIx and aPWV were measured via applanation tonometry (SphygmoCor, Atcor Medical, Australia).
Results: The cohort was split into those who adhered (n=17) and did not adhere (n=19) to the programme. MMP-9 expression, MAP and AIx all decreased significantly in the exercise-adherent group (cf. the non-adherent group), while significant correlations were seen between: (i) ΔMMP-9 expression and ΔMET-minutes/wk; (ii) ΔMMP-9 expression and ΔAIx; (iii) ΔAIx and ΔMET-minutes/wk (P<0.05 in all cases). aPWV did not change significantly between the groups.
Conclusions: These findings suggest that exercise-induced down-regulation of MMP-9 may contribute to reduced ECM degradation and therefore ameliorate vascular remodelling. Additional studies are needed to explore these findings further; however, these data may provide a biomolecular mechanism for aerobic exercises ability to delay age-related increases in arterial stiffening.