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A Swine Model of Neonatal Asphyxia
Published on: October 11, 2011
Comparison of insulin sensitivity between healthy neonatal foals and horses using minimal model analysis
Hannah M Kinsella1, Laura D Hostnik1, Hailey A Snyder1
1College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States of America.
Insights
Newborn foals exhibit higher insulin sensitivity than adult horses, challenging previous assumptions about equine neonatal glucose tolerance. This heightened sensitivity may be an evolutionary adaptation for energy conservation after birth.
Area of Science:
- Veterinary Medicine
- Endocrinology
- Metabolic Research
Background:
- Equine neonates are presumed to have impaired glucose tolerance due to immature pancreatic endocrine systems.
- Limited research exists on insulin sensitivity in newborn foals using dynamic testing.
- Understanding neonatal insulin sensitivity is crucial for equine health and development.
Purpose of the Study:
- To assess and compare insulin sensitivity in neonatal foals versus adult horses.
- To utilize the insulin-modified frequently sampled intravenous glucose tolerance test (I-FSIGTT) for dynamic testing.
- To investigate key metabolic parameters including insulin sensitivity (SI) and disposition index (DI).
Main Methods:
- Healthy neonatal foals (n=12) and adult horses (n=8) underwent I-FSIGTT with intravenous dextrose and insulin administration.
- Minimal model analysis was employed to calculate insulin sensitivity (SI), acute insulin response to glucose (AIRg), glucose effectiveness (Sg), and disposition index (DI).
- Nonparametric statistical methods were used for data analysis, reporting median and interquartile range (IQR).
Main Results:
- Neonatal foals demonstrated significantly higher insulin sensitivity (SI) compared to adult horses (p < 0.0001).
- The disposition index (DI) was also significantly higher in foals than in adult horses (p < 0.0001).
- While AIRg and Sg did not differ, the modified insulin to glucose ratio (MIRG) and homeostasis model assessment of beta cell function (HOMA-BC%) indicated greater insulin sensitivity in foals.
Conclusions:
- Healthy neonatal foals possess significantly higher insulin sensitivity in the early days of life.
- This finding contrasts with the prevailing view of impaired glucose tolerance in equine neonates.
- Elevated insulin sensitivity in newborn foals may represent an evolutionary adaptation to conserve energy during the transition to extrauterine life.
Abstract:
The equine neonate is considered to have impaired glucose tolerance due to delayed maturation of the pancreatic endocrine system. Few studies have investigated insulin sensitivity in newborn foals using dynamic testing methods. The objective of this study was to assess insulin sensitivity by comparing the insulin-modified frequently sampled intravenous glucose tolerance test (I-FSIGTT) between neonatal foals and adult horses. This study was performed on healthy neonatal foals (n = 12), 24 to 60 hours of age, and horses (n = 8), 3 to 14 years of age using dextrose (300 mg/kg IV) and insulin (0.02 IU/kg IV). Insulin sensitivity (SI), acute insulin response to glucose (AIRg), glucose effectiveness (Sg), and disposition index (DI) were calculated using minimal model analysis. Proxy measurements were calculated using fasting insulin and glucose concentrations. Nonparametric statistical methods were used for analysis and reported as median and interquartile range (IQR). SI was significantly higher in foals (18.3 L·min-1· μIU-1 [13.4-28.4]) compared to horses (0.9 L·min-1· μIU-1 [0.5-1.1]); (p < 0.0001). DI was higher in foals (12 × 103 [8 × 103-14 × 103]) compared to horses (4 × 102 [2 × 102-7 × 102]); (p < 0.0001). AIRg and Sg were not different between foals and horses. The modified insulin to glucose ratio (MIRG) was lower in foals (1.72 μIUinsulin2/10·L·mgglucose [1.43-2.68]) compared to horses (3.91 μIU insulin2/10·L·mgglucose [2.57-7.89]); (p = 0.009). The homeostasis model assessment of beta cell function (HOMA-BC%) was higher in horses (78.4% [43-116]) compared to foals (23.2% [17.8-42.2]); (p = 0.0096). Our results suggest that healthy neonatal foals are insulin sensitive in the first days of life, which contradicts current literature regarding the equine neonate. Newborn foals may be more insulin sensitive immediately after birth as an evolutionary adaptation to conserve energy during the transition to extrauterine life.
