Altered chronic glycemic control in a clinically relevant model of rat thoracic spinal contusion

Bioscience Reports, 2022 · DOI: https://doi.org/10.1042/BSR20221699 · Published: December 23, 2022

Simple Explanation

This study investigates how spinal cord injuries (SCIs) affect blood sugar control in rats, especially when combined with a high-fat diet. The researchers aimed to understand why people with SCIs have a higher risk of developing type 2 diabetes. Rats with SCIs and those without were fed either a standard diet or a high-fat diet for 16 weeks. The researchers then measured their blood sugar levels and insulin sensitivity, and examined key components of the gut-brain axis. The study found that SCI rats had higher blood glucose levels after consuming a mixed-nutrient meal, and that the normal relationship between GLP-1 (a hormone that helps regulate blood sugar), glucose, and insulin was disrupted in these rats.

Study Duration

16 weeks

Participants

Long Evans male rats (N=40 initially, N=9-11 per final group)

Evidence Level

Not specified

Key Findings

1
HFD consumption equally induced weight gain in SCI and naïve rats over chow rats.
2
Gavage of ENSURE resulted in high glucagon-like peptide 1 (GLP-1) release from SCI rats over naïve controls.
3
Increased glucagon mRNA in the pancreas and reduced immunoreactive glucagon-positive staining in the pancreas in SCI rats compared with controls suggested increased glucagon turnover.

Research Summary

The study investigates the body-weight and glycemic effects of consuming a normal chow diet or a diet high in saturated fat for 16 weeks following a T10 contusion injury. The data collected show a potentially novel role of GLP-1 in the pathogenesis of reduced glucose control following SCI. The study consistently identified that the Long Evans SCI rats have higher fasting glucose levels and are glucose-intolerant compared with controls when gavaged with dextrose starting at 3 months after injury.

Practical Implications

Understanding GLP-1's Role

Further research is needed to understand the nuances of changes in the biological activity of GLP-1 in the SCI model, potentially using GLP-1 modulating drugs.

Targeting DPP4

Future studies should investigate the cause of elevated DPP4 and the timing of its onset following injury, potentially sampling the portal circulation to understand DPP4 activity.

Dietary Interventions

The findings suggest the need for tailored dietary interventions for individuals with SCI to manage glycemic control, considering the altered responses to nutrients and hormones.

Study Limitations

1
The study did not use protease inhibitors to collect samples, preventing the study of active vs. inactive GLP-1.
2
The study did not investigate time points before 15 weeks post-injury, limiting the understanding of the evolution of GLP-1 sensitivity changes.
3
The study did not investigate whether the circulating GLP-1 levels influence gastric emptying after thoracic SCI.

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