Postprandial Lipid Tracer and Exercise in Spinal Cord Injury
Condition: Spinal Cord Injuries
MeSH terms: Spinal Cord Injuries; Wounds and Injuries
Study type: Interventional

Summary: 
      This study investigates the effect of upper extremity exercise on postprandial lipemia (PPL)
      in persons with spinal cord injury (SCI). Participants are measured at rest and fed a
      standardized meal following seated rest (CON) or arm cycling exercise (ACE). The meal is
      infused with "stable isotope lipid tracers" that allow for determination of the end fates of
      the fat in the meal.
    

Detailed description: 
      Spinal cord injury (SCI) results in dysregulation of fat metabolism that increases the risk
      of morbidity and mortality from cardioendocrine disease. Excessive accumulation of visceral
      fat after SCI is a serious risk component for cardioendocrine disease and results in part
      from pronounced hypertriglyceridemia following ingestion of fat-containing meals (i.e.,
      exaggerated postprandial lipemia; PPL). Although exaggerated PPL is well documented in
      persons with SCI, its etiology is unknown. Specifically, it remains to be determined to what
      extent exaggerated PPL in those with SCI results from impairments in the use of exogenous
      (dietary) and/or endogenous (stored) fats. Additionally, it is not known if exercise improves
      postprandial fat use in a manner that alleviates the exaggerated PPL in this population and
      reduces the risk of cardioendocrine disease.

      The objective of the this study is to examine the mechanisms of exaggerated PPL in those with
      SCI and the effects of an acute pre-meal exercise bout by employing novel stable isotope
      tracer techniques. In persons without SCI, it is well established that pre-meal exercise
      lowers PPL in part by improving the use of exogenous and endogenous fats. While muscle
      atrophy and blunted sublesional sympathetic activity following SCI may hinder fat use,
      preliminary data indicate that fat use is increased during recovery from exercise in the
      postabsorptive (fasted) state in this population. Thus, the investigators hypothesize that
      decreased use of exogenous and endogenous fats contributes to exaggerated PPL in SCI, and
      that pre-meal exercise will reduce PPL due to increased use of both fat sources.
    

Intervention name(s): Seated control (CON); Arm cycle exercise (ACE); Liquid meal
Intervention type(s): Behavioral; Behavioral; Behavioral
Intervention description(s): Seated rest; Arm cycling at a continuous power output; Liquid meal of 0.5 L volume containing 20 kcal/kg fat free mass (FFM) and 5 mg/kg FFM of uniformly 13-carbon labeled palmitate ([U-13C]palmitate) at a macronutrient distribution of 50% carbohydrate, 35% fat, and 15% protein (by kcal).
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: Mixed-crossover: three separate groups (paraplegia, tetraplegia, and neurologically intact) undergo two conditions (seated control and exercise) in a randomized order.
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: lipemia; feeding; paraplegia; tetraplegia; physical activity; macronutrient metabolism