Oxidized low-density lipoprotein, matrix-metalloproteinase-8 and carotid atherosclerosis in spinal cord injured subjects.

OBJECTIVE

Previous reports have indicated that subjects with chronic spinal cord injury (SCI) exhibit increased cardiovascular risk compared to able-bodied individuals. This study investigated the relationship between plasmatic oxidized low-density lipoprotein (OxLDL), matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) levels and vascular remodeling in SCI subjects and the role of physical activity in this regard.

METHODS

We studied 42 men with chronic (≥2 years) SCI [18 sedentary (S-SCI) and 24 physically active (PA-SCI)] and 16 able-bodied men by clinical, anthropometric, laboratory, and carotid intima-media thickness (IMT) analysis. All enrolled subjects were normotensive, non-diabetics, non-smokers and normolipemic. Plasmatic OxLDL, MMP-2, MMP-8, MMP-9, TIMP-1 and TIMP-2 levels were determined by enzyme-linked immunosorbent assay.

RESULTS

Carotid IMT, IMT/diameter ratio and OxLDL levels of PA-SCI and able-bodied subjects were statistically similar. Conversely, S-SCI subjects exhibited higher IMT, IMT/diameter ratio and OxLDL levels compared to PA-SCI (p < 0.01, p < 0.001 and p = 0.01, respectively) and able-bodied (p < 0.001 for all) individuals. Results of bivariate correlation analysis including all injured subjects showed that carotid IMT and IMT/diameter ratio only correlated with OxLDL, MMP-8 and MMP-8/TIMP-1 ratio. Further stepwise regression analysis adjusted for the presence or not of physical activity and age showed that OxLDL was associated with carotid IMT and IMT/diameter ratio, while MMP-8 was associated with IMT/diameter ratio in SCI individuals.

CONCLUSIONS

Plasmatic OxLDL and MMP-8 levels are associated with carotid atherosclerosis and there is an interaction among physical inactivity, atherosclerosis and OxLDL in SCI individuals.