Location: Children's Nutrition Research CenterTitle: Continuous nutrient administration decreases insulin sensitivity in neonatal pigs Author
|Burrin, Douglas - Doug|
Submitted to: Journal of Parenteral and Enteral Nutrition
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2009
Publication Date: 3/1/2009
Citation: Stoll, B., Puiman, P., Benight, N., Bauchart-Thevret, C., Burrin, D.G. 2009. Continuous nutrient administration decreases insulin sensitivity in neonatal pigs [abstract]. Journal of Parenteral and Enteral Nutrition. 33(2):202. Interpretive Summary:
Technical Abstract: We previously showed that chronic TPN compared to intermittent feeding of a formula results in hepatic insulin resistance and steatosis in neonatal pigs. We hypothesized that the route of feeding (IV vs enteral) rather than the nature of the diet (elemental vs polymeric) or the feeding regimen (continuous vs intermittent) contributed to the outcome. Neonatal pigs (3-d-old, n = 47), implanted with catheters in the jugular vein, carotid artery, and stomach were fed a complete elemental diet (amino acid, glucose, fat) continuously parenterally(TPN), continuously enterally (CEN), or intermittently enterally (IEN, every 4-5h) or received a milk-based formula intermittently (FORM, every 4-5h) for 10-14d. At the end of the study period, subgroups of pigs (n = 5-8/treatment), were submitted to hyperinsulinemic-euglycemic clamps, whereby insulin was infused at 180 ng/kg(-0.67/)min(-1) to achieve plasma insulin levels of 60 muU/mL(-1), while glucose was maintained at fasting levels. Following the clamp, pigs were euthanized, and tissues were collected for further analysis. The glucose infusion rate(mg/kg(-1)/min(-1)) required to maintain blood glucose at fasting levels was not different between TPN and CEN (17.76 vs 15.88; p>=0.05). IEN was significantly higher than TPN or CEN and tended to be lower than FORM (23.53 vs 29.4). Liver weights (g/kg(-1) body weight) were similar in CEN, IEN, and FORM (25.0, 24.4, 27.8) but significantly lower than in TPN (38.0;p<=0.05). Liver triglycerides (TG; mg/g -1 liver) were not different between CEN and IEN (29.26 vs 36.64; p<=0.05). Liver TG in TPN were lower than in CEN or IEN (p<=0.05) but were higher than in FORM (15.58 vs 5.64; p=0.05). We conclude that, when given continuously, the route of elemental nutrient administration (enteral vs parenteral) does not alter insulin sensitivity. However, intermittent nutrient administration, given either in elemental or polymeric form, increased insulin sensitivity compared to continuous feeding. Enteral elemental nutrients, given continuously or intermittently, were associated with marked steatosis, but this was not strictly linked to insulin sensitivity. Thus, it appears that the pattern (continuous vs intermittent) has a greater impact than the route (enteral vs parenteral) of nutrient administration on insulin sensitivity. It remains to be seen whether feeding FORM continuously or TPN intermittently decreases or increases insulin sensitivity, respectively.