Low Frequency Electrically Induced Muscle Exercise Modulates Glucose Tolerance and Uric Acid Levels in People with SCI
Authors: Petrie Michael A , Kimball Amy L , Lee Jinhyun , McCue Patrick M , Johnson Kristin A , Sharma Arpit , Taylor Eric B , Shields Richard K 
Published: June 2021

Regular exercise is an important strategy to prevent the development of several chronic non‐communicable diseases (NCDs), including metabolic inflexibility and diabetes. Skeletal muscle increases glucose uptake through two distinct pathways: the insulin receptor sensitivity pathway and the exercise induced AMPK pathway. Because people with paralysis are unable to move, they never reap the benefits of muscle exercise/activity following a meal. In addition, there is a knowledge gap regarding the influence of electrically induced exercise on nitrogen metabolism.

Purpose

To determine if electrically induced exercise using electrical muscle stimulation regulates the glycemic response after an oral glucose load in people with and without a SCI. We also determined if uric acid and lactate are increased in people with SCI after electrically induced exercise.

Methods

10 and 9 people with and without a SCI participated in this study. Participants completed 2 sessions of a 2‐hour oral glucose tolerance test at least 7 days apart. 15 minutes after ingesting a 75g glucose beverage, participants sat passively (control) or were given a dose of electrically induced muscle stimulation delivered at a 3Hz frequency for 1‐hour, then rested for the next hour. Glucose, insulin, uric lactate, and uric acid were measured from venous blood draws at baseline, 60 minutes, and 120 minutes. Capillary glucose measurements were performed at baseline, 30, 60, 90, and 120 minutes. A mixed design analysis of variance was used for all comparisons with pairwise comparisons where appropriate. All participants provided written consent approved by the University of Iowa Institutional Review Board in compliance with the Declaration of Helsinki.

Results

At baseline, there was no significant difference in glucose (89.6±3.2 and 88.8±3.4 mg/dL, p=0.88) and lactate (1.4±0.2 and 1.4±0.2 mmol/L, p=0.96) concentrations between people with and without SCI. We found significant differences between baseline insulin (14.4±1.7 and 5.6±1.8 μUI/mL, p=0.003) and uric acid (5.9±0.6 and 3.9±0.6 mg/dL, p=0.036) concentrations between people with and without SCI. Exercise increased the peak lactate (6.0±0.3 and 1.7±0.3 mmol/L, p<0.001) and uric acid (6.9±0.1 and 5.6±0.2 mg/dL, p=0.005) levels during the oral glucose tolerance test in people with SCI. However, exercise only increased peak lactate (2.0±0.06 and 1.5±0.06 mmol/L, p=0.002) concentrations during the oral glucose tolerance test for people without SCI.

Conclusions

A dose of low frequency electrically induced muscle exercise attenuated the severe glycemic response in people with SCI after a meal. Additionally, electrically induced exercise increased uric acid and lactate levels suggesting a potential increase stress to the renal system. These findings offer a unique strategy for people who are paralyzed to improve their glucose tolerance after a meal. However, attention to nitrogen metabolism balance will be an important area for future research.

Support or Funding Information Research Support: This study was funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development: R01HD084645, R01HD082109

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.