Amino Acid Availability Regulates the Effect of Hyperinsulinemia on Skin Protein Metabolism in Pigs

Abstract

Background: Insulin is known as an anabolic agent; however, its effect on skin protein metabolism is not well understood. Results: Hyperaminoacidemia alters the effect of hyperinsulinemia on skin protein metabolism in pigs. Conclusion: Hyperinsulinemia itself was not anabolic but rather affected skin amino acid cycling. Significance: Knowing the effect of hyperinsulinemia on skin protein metabolism will help with understanding the pathophysiology of skin conditions.

Lamellar energy metabolism and perfusion in the euglycaemic hyperinsulinaemic clamp model of equine laminitis

“…Although lamellar carbohydrate metabolism was not profoundly altered by hyperinsulinaemia and there was no apparent effect on plasma lactate, systemic or local alterations in lipid or protein metabolism were not examined and may warrant further investigation as, for example, profound reductions in plasma amino acid concentrations are observed during the euglycaemic hyperinsulinaemic clamp in horses and other species and altered amino acid availability could affect lamellar homeostasis.…”

Plasma amino acid concentrations during experimental hyperinsulinemia in 2 laminitis models

“…Insulin is a major regulator of protein metabolism, with hyperinsulinemia having been shown to decrease plasma amino acid concentration by altering amino acid utilization and protein turnover in several mammalian tissues including skeletal muscle and skin 14‐18 . Importantly, hyperinsulinemia‐induced hypoaminoacidemia previously has been reported in horses undergoing a short‐term (2 hour) EHC 15 .…”

“…Insulin is a major regulator of protein metabolism, with hyperinsulinemia having been shown to decrease plasma amino acid concentration by altering amino acid utilization and protein turnover in several mammalian tissues including skeletal muscle and skin. [14][15][16][17][18] Importantly, hyperinsulinemia-induced hypoaminoacidemia previously has been reported in horses undergoing a short-term (2 hour) EHC. 15 This finding may have relevance to laminitis because hypoaminoacidemia causes cutaneous pathology in humans and dogs, which resolves after therapeutic correction of blood amino acid concentrations.…”

Studies on the pathogenesis of insulin-induced laminitis in horses

“…Furthermore, lamellar protein metabolism was not examined and this warrants further investigation as profound reductions in plasma amino acid concentrations are observed during the EHC in horses and other species [242][243][244] and altered amino acid availability could affect lamellar structural protein homeostasis.…”

“…It is possible that the different sampling intervals (4 hours vs 6 hours) could have differentially affected microdialysate metabolite concentrations due to metabolite degradation over the course of the sampling interval, however this factor has not been investigated. It is important to also consider that the supraphysiological hyperinsulinaemia of the EHC model may not mimic the pathophysiological processes occurring in natural cases of endocrinopathic laminitis and this is also a limitation of the current study.Although lamellar carbohydrate metabolism was not profoundly altered by hyperinsulinaemia and there was no apparent effect on plasma lactate, systemic or local alterations in lipid or protein metabolism were not examined and may warrant further investigation as, for example, profound reductions in plasma amino acid concentrations are observed during the euglycaemic hyperinsulinaemic clamp in horses and other species[242][243][244] and altered amino acid availability could affect lamellar homeostasis.This study demonstrates that hyperinsulinaemia causes laminitis in the absence of ischaemia or cellular energy deprivation in the EHC model of endocrinopathic laminitis.…”