Effects of the insulin-sensitizing drug pioglitazone and lipopolysaccharide administration on insulin sensitivity in horses.

The research investigates the effects of the insulin-sensitizing drug pioglitazone on insulin sensitivity in horses, particularly in relation to obesity and laminitis. However, it was found that the drug did not improve basal insulin sensitivity but altered the abundance of glucose and lipid transporters in muscle and adipose tissues.

Objective and Methods

• The objective of this study was to determine if the drug pioglitazone (PG) could increase insulin sensitivity and the abundance of glucose and lipid transporters in adipose (fat) and skeletal muscle tissues, thereby mitigating risks associated with obesity in horses.
• The researchers conducted the study on sixteen lean, healthy horses. Eight of these horses were administered 1 mg PG per kilogram of bodyweight for 12 days. The other eight horses acted as untreated controls.
• Following the administration of PG, insulin resistance was artificially induced in the horses through an Intravenous (IV) injection of lipopolysaccharide (LPS).
• Both the treated and untreated horses were subjected to tests for peripheral insulin sensitivity and biopsies of subcutaneous adipose tissue (fat tissue under the skin) and skeletal muscle before and after the treatments, and 24 hours after LPS administration.

Results

• The research did not find that PG treatment improved basal insulin sensitivity in horses or mitigated LPS-induced insulin resistance, contradicting the initial hypothesis of the study. This indicates that PG may not help in increasing insulin sensitivity in horses.
• However, the study did find that the transcript abundance of glucose and lipid transporters was altered in both skeletal muscle and subcutaneous adipose tissues. This suggests that PG has some effect on the regulation of glucose and lipids in these tissues.

Conclusions

• The study concluded that either a higher dose or a longer treatment duration of PG might be required for physiological effects to be observed.
• Despite these findings, the researchers maintained that PG is a novel therapeutic agent that necessitates future investigation in horses to determine its potential treatment efficacy.