Evaluation of peripheral blood polymorphonuclear cell functions after an oral carbohydrate overload in obese and insulin dysregulated horses.

This study investigates how a high-sugar diet impacts the immune system of horses with varying body weight and insulin tolerance levels. The researchers found that obese horses with insulin dysregulation displayed a significantly lower ability to clear out bad cells and infections, although this ability increased after a high-sugar meal. Additionally, the initially robust production of immune defense cells (reactive oxygen species) observed in obese horses with normal insulin levels decreased after they consumed a high-sugar meal.

Research Context

• This research was conducted due to the increasing prevalence of obesity and insulin dysregulation (ID) in horse populations across the world. There is known immune impairment in humans who suffer from similar metabolic disorders, and this study aims to understand this phenomenon in horses.
• The focus is on the effect of acute induced high blood sugar on various functions of polymorphonuclear cells (PMNs), a type of white blood cell. These functions include clearing out bad cells and infections (phagocytosis), inducing cell death (apoptosis), and producing immune defense cells (oxidative burst activity).

Methodology

• The researchers split seventeen adult horses into three groups based on their body condition score (BCS) and metabolic status. These groups were lean and insulin sensitive (lean-IS), obese and insulin sensitive (obese-IS), and obese with insulin dysregulation (obese-ID). The degree of insulin dysregulation was judged through an insulin tolerance test.
• The researchers induced high blood sugar through an oral glucose test and carried out the assessments both before and after two hours of carbohydrate overload.

Findings

• The researchers found no difference in the level of apoptosis between the three groups at any time.
• However, they discovered that the obese-ID group initially had a significantly lower phagocytic capacity compared to the other groups. This capacity increased after high-sugar meal consumption.
• In the obese-IS group, there was initially a significantly higher production of reactive oxygen species. This however dropped significantly following the consumption of a high-sugar meal.

Conclusion

• The study concluded that both the metabolic status of horses and the intake of high glucose meals alter how well the immune system functions, specifically regarding phagocytosis and oxidative burst.