Experimental Spinal Cord Injury Causes Left-Ventricular Atrophy and Is Associated with an Upregulation of Proteolytic Pathways.
Level 5 - mechanism / opinion, no new human data
Controlled animal laboratory experiment without human clinical data
PubMed 29877162 · doi:10.1089/neu.2017.5624
What was done
Rats subjected to chronic experimental spinal cord injury (SCI) and control rats were evaluated 12 weeks post-injury using in vivo cardiac magnetic resonance imaging (MRI), left-ventricular (LV) pressure-volume catheterization, histological analysis, and molecular assessments of myocardial tissue and neurohumoral markers.
What was found
At 12 weeks post-injury, SCI rats exhibited significantly reduced LV mass compared to controls (413 ± 28.6 mg vs. 525 ± 38.8 mg; p = 0.0009), decreased LV end-diastolic volume (221 ± 35 μL vs. 364 ± 44 μL; p = 0.0004), and impaired contractility as measured by the end-systolic pressure-volume relationship (0.76 ± 0.11 mm Hg/μL vs. 1.31 ± 0.31 mm Hg/μL; p = 0.0045). SCI was also accompanied by significantly lower blood pressure, reduced circulating norepinephrine, elevated angiotensin II, reduced cardiomyocyte size, increased expression of angiotensin II type 1 and TGF-beta receptors 1 and 2, and a greater than two-fold increase in muscle ring finger-1 and Beclin-1 protein levels.
Why it matters
This study shows that cardiac atrophy and systolic dysfunction following spinal cord injury are associated with the activation of ubiquitin-proteasome and autophagy-lysosomal proteolytic pathways, clarifying the mechanistic links between autonomic disruption and myocardial remodeling.
Limits
The study was conducted entirely in a rodent model, which may not fully replicate human pathophysiology. The abstract does not report the total sample size (n per group), injury level or severity details, or whether these cellular changes can be reversed by intervention.
Cited by
- supports Patients with spinal cord injuries experience an approximate 25% reduction in cardiac mass due to physical inactivity.