Cardiometabolic Risk Factors in Experimental Spinal Cord Injury

Abstract

Cardiometabolic risk factors are sorely underreported after spinal cord injury (SCI), despite the high prevalence of metabolic disorders and cardiovascular mortality in this population. Body-composition analysis and serum-lipid profiling are two assessments that are beginning to be more widely used to document metabolic changes after clinical SCI. Individuals with SCI have been reported to carry increased visceral fat and to exhibit altered serum-lipid levels. However, little is known about the development of these cardiometabolic risk factors in animal models. Using a combination of magnetic resonance imaging (MRI) and adipose tissue dissection, we show that visceral and subcutaneous adipose tissue were both increased at 1 month, but not at 1 week, after complete T3 SCI in rats. Additionally, at 1 month post injury, T3 SCI rats exhibited nonfasting serum hypertriglyceridemia, a result obtained using both standard clinical methods and a home cholesterol monitoring device (CardioChek). Interestingly, at 1 month post injury, rats with complete T10 SCI did not show an increase in either visceral adiposity or serum triglyceride levels. The fact that complete high-thoracic SCI disrupts lipid metabolism and perturbs fat storage in the subacute period, while low-thoracic SCI does not, suggests that differences in descending sympathetic control of adipose tissue might play a role in these changes. These results provide the first evidence of cardiometabolic risk factors in experimental animals with SCI, and are a starting point for investigations of the etiology of obesity and metabolic dysfunctions that often accompany SCI.

Spinal Cord Injury Causes Chronic Liver Pathology in Rats

“…This is in contrast to previous work showing more severe effects after higher-level injuries on autonomic dysreflexia, inflammation, and cardiovascular problems. 16,66,67 Both injury levels used here, however, completely (cervical) or partially (thoracic) disrupt descending control of sympathetic neurons innervating the liver and, thus, differences in hepatic changes between cervical and thoracic injuries were subtle. To further test this, a cohort of animals received a lumbar SCI to spare sympathetic innervation to the liver.…”

“…16,[32][33][34][35] To determine if post-injury changes in the liver were dependent on the level of SCI, we examined liver inflammation and lipid accumulation after midline cervical (C5 level) contusion injury in rats. Similar to thoracic SCI, hepatic CD68 mRNA significantly increased by 1 dpi, reaching levels *1000-fold higher than in naïve/uninjured livers (Fig.…”

Effects of spinal cord injury on body composition and metabolic profile – Part I

“…Waist circumference (WC) plays a simple role in identifying individuals with SCI who are at risk of developing metabolic syndrome (MS) as well as altered lipid profiles post-injury. [52][53][54][55][56][57][58][59][60][61][62][63] In the AB population, WC…”

“…62 However, an earlier study that used the SCI animal model contradicted these findings and showed that rats with T3 level of injury or above had greater VAT accumulation. 63 The regional role of VAT and SAT in determining the metabolic profile warrants further investigation. Reducing insulin resistance and other metabolic derangements is a valuable goal; studies should examine whether there are rehabilitation strategies that by maintaining FFM through diet and exercise, among other things, can attenuate the infiltration of adipose tissue in non-subcutaneous sites.…”

Structural neuroplasticity following T5 spinal cord transection: increased cardiac sympathetic innervation density and SPN arborization

“…However, mortality rates in the chronic period (Ͼ2 yr following injury) have changed very little, and people with SCI have a significantly reduced life expectancy (17,28,81). The reduced life expectancy is due, in part, to a higher prevalence and earlier onset of cardiovascular diseases (57).…”