1.
Trafficking of nonesterified fatty acids in insulin resistance and relationship to dysglycemia.
Walker, RE, Ford, JL, Boston, RC, Savinova, OV, Harris, WS, Green, MH, Shearer, GC
American journal of physiology. Endocrinology and metabolism. 2020;(3):E392-E404
Abstract
In adipose, insulin functions to suppress intracellular lipolysis and secretion of nonesterified fatty acid (NEFA) into plasma. We applied glucose and NEFA minimal models (MM) following a frequently sampled intravenous glucose tolerance test (FSIVGTT) to assess glucose-specific and NEFA-specific insulin resistance. We used total NEFA and individual fatty acids in the NEFA MM, comparing the model parameters in metabolic syndrome (MetSyn) subjects (n = 52) with optimally healthy controls (OptHC; n = 14). Results are reported as mean difference (95% confidence interval). Using the glucose MM, MetSyn subjects had lower [-73% (-82, -57)] sensitivity to insulin (Si) and higher [138% (44, 293)] acute insulin response to glucose (AIRg). Using the NEFA MM, MetSyn subjects had lower [-24% (-35, -13)] percent suppression, higher [32% (15, 52)] threshold glucose (gs), and a higher [81% (12, 192)] affinity constant altering NEFA secretion (ϕ). Comparing fatty acids, percent suppression was lower in myristic acid (MA) than in all other fatty acids, and the stearic acid (SA) response was so unique that it did not fit the NEFA MM. MA and SA percent of total were increased at 50 min after glucose injection, whereas oleic acid (OA) and palmitic acid (PA) were decreased (P < 0.05). We conclude that the NEFA MM, as well as the response of individual NEFA fatty acids after a FSIVGTT, differ between OptHC and MetSyn subjects and that the NEFA MM parameters differ between individual fatty acids.
2.
Reducing glucose infusion safely prevents hyperglycemia in post-surgical children.
Verbruggen, SC, de Betue, CT, Schierbeek, H, Chacko, S, van Adrichem, LN, Verhoeven, J, van Goudoever, JB, Joosten, KF
Clinical nutrition (Edinburgh, Scotland). 2011;(6):786-92
Abstract
BACKGROUND & AIMS To investigate the effects of two different glucose infusions on glucose homeostasis and amino acid metabolism in post-surgical children. METHODS This randomized crossover study evaluated glucose and amino acid metabolism in eight children (age 9.8 ± 1.9 months, weight 9.5 ± 1.1 kg) admitted to a pediatric intensive care unit in a tertiary university hospital after surgical correction for non-syndromal craniosynostosis. Patients were randomized to receive low (LG; 2.5 mg kg(-1) min(-1)) and standard (SG; 5.0 mg kg(-1) min(-1)) glucose infusion in a crossover setting. After a bolus (4 g kg(-1)) of deuterium oxide, we conducted a primed, constant, 8 h tracer infusion with [6,6-²H₂]Glucose, [1-¹³C]Leucine, [ring-²H₅]Phenylalanine and [3,3-²H₂]Tyrosine. RESULTS SG resulted in hyperglycemia (defined as > 6.1 mmol L(-1)), while during LG plasma glucose levels were normoglycemic (5.9 ± 0.6 vs. 7.5 ± 1.7 mmol L(-1); LG vs. SG respectively, p = 0.02). Hypoglycemia did not occur during LG infusion. Endogenous glucose production was not fully suppressed during the hyperglycemic state under SG and increased with reduced glucose infusion (2.6 ± 1.5 vs. 1.1 ± 1.4 mg kg(-1) min(-1); LG vs. SG; p = 0.05). Whole body protein balance derived from leucine and phenylalanine kinetics was slightly negative but not further affected with a decrease in glucose infusion. CONCLUSIONS The current recommended glucose infusion induces hyperglycemia in post-surgical children. A reduced glucose infusion safely reduced high glucose levels, while children were capable to sustain normoglycemia with increased endogenous glucose production. The reduced glucose infusion did not exacerbate the mild catabolic state in which the patients were.