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Objective: To investigate the mechanism for increased ketogenesis following treatment with the SGLT2 inhibitor dapagliflozin in people with type 2 diabetes., Research Design and Methods: The design was a double-blind, placebo-controlled, crossover study with a 4-week washout period. Participants received dapagliflozin or placebo in random order for 4 weeks. After each treatment, they ingested 30 mL of olive oil containing [U-13C]palmitate to measure ketogenesis, with blood sampling for 480 min. Stable isotopes of glucose and glycerol were infused to measure glucose flux and lipolysis, respectively, at 450-480 min., Results: Glucose excretion rate was higher and peripheral glucose uptake lower with dapagliflozin than placebo. Plasma β-hydroxybutyrate (BOHB) concentrations and [13C2]BOHB concentrations were higher and glucose concentrations lower with dapagliflozin than placebo. Nonesterified fatty acids (NEFAs) were higher with dapagliflozin at 300 and 420 min, but lipolysis at 450-480 min was not different. Triacylglycerol at all time points and endogenous glucose production rate at 450-480 min were not different between treatments., Conclusions: The increase in ketone enrichment from the ingested palmitic acid tracer suggests that meal-derived fatty acids contribute to the increase in ketones during treatment with dapagliflozin. The increase in BOHB concentration with dapagliflozin occurred with only minimal changes in plasma NEFA concentration and no change in lipolysis. This finding suggests a metabolic switch to increase ketogenesis within the liver., (© 2022 by the American Diabetes Association.)

Objective: The risk of hypoglycemia in people with insulin-treated diabetes has debarred them from certain "safety-critical" occupations, including flying commercial aircraft. This report evaluates the effectiveness of a protocol enabling a large cohort of insulin-treated pilots to fly commercially., Research Design and Methods: This was an observational study of pilots with insulin-treated diabetes who were granted medical certification to fly commercial and noncommercial aircraft. Clinical details, pre- and in-flight (hourly and 30 min before landing) blood glucose values were correlated against the protocol-specified ranges: green (5-15 mmol/L), amber (low, 4-4.9 mmol/L; high, 15.1-20 mmol/L), and red (low, <4 mmol/L; high, >20 mmol/L)., Results: A total of 49 pilots with type 1 (84%) or type 2 (16%) diabetes who had been issued class 1 or class 2 certificates were studied. Median diabetes duration was 10.9 years. Mean HbA 1c was 7.2% (55.0 mmol/mol) before certification and 7.2% (55.1 mmol/mol) after certification ( P = 0.97). Blood glucose values ( n = 38,621) were recorded during 22,078 flying hours. Overall, 97.69% of measurements were within the green range, 1.42% within the low amber range, and 0.75% within the high amber range. Only 0.12% of readings were within the low red range and 0.02% within the high red range. Out-of-range readings declined from 5.7% in 2013 to 1.2% in 2019. No episodes of pilot incapacitation occurred, and glycemic control did not deteriorate., Conclusions: The protocol is practical to implement, and no events compromising safety were reported. This study represents what is, to our knowledge, the most extensive data set from people with insulin-treated diabetes working in a "safety-critical" occupation, which may be relevant when estimating risk in other safety-critical occupations., (© 2020 by the American Diabetes Association.)

Objective: To determine the effect of the sodium-glucose cotransporter 2 inhibitor dapagliflozin on glucose flux, lipolysis, and ketone body concentrations during insulin withdrawal in people with type 1 diabetes., Research Design and Methods: A double-blind, placebo-controlled crossover study with a 4-week washout period was performed in 12 people with type 1 diabetes using insulin pump therapy. Participants received dapagliflozin or placebo in random order for 7 days. Stable isotopes were infused to measure the glucose R a , R d , and lipolysis. At isotopic steady state, insulin was withdrawn, and the study was terminated after 600 min or earlier if blood glucose reached 18 mmol/L, bicarbonate <15 mmol/L, venous pH <7.35, or capillary ketones >5.0 mmol/L., Results: At baseline, glucose R a was significantly higher for the dapagliflozin group than the placebo group. Following insulin withdrawal, plasma glucose concentrations at the end point were significantly lower with dapagliflozin than placebo and glucose R d area under the curve (AUC) 0-180 min and β-hydroxybutyrate (BOHB) AUC 0-180 min were significantly higher. There was a small but significantly higher glycerol R a (measure of lipolysis) AUC 0-180 min with dapagliflozin. Nonesterified fatty acid concentrations were not different between treatments. When divided by BMI >27 and <27 kg/m 2 , basal glucose R a , BOHB, and glycerol R a AUC 0-180 min were significantly higher in the low-BMI group with dapagliflozin treatment versus the low-BMI group with placebo., Conclusions: During insulin withdrawal, the increase in BOHB with dapagliflozin may be partially due to increased lipolysis. However, reduced renal excretion, reduced BOHB uptake by peripheral tissues, or a metabolic switch to increased ketogenesis within the liver may also play a role., (© 2020 by the American Diabetes Association.)

Objective: Insulin detemir lacks the usual propensity for insulin to cause weight gain. We investigated whether this effect was a result of reduced energy intake and/or increased energy expenditure., Research Design and Methods: A 32-week, randomized crossover design trial was undertaken in 23 patients with type 1 diabetes. Patients on a basal-bolus regimen (with insulin aspart as the bolus insulin) were randomly assigned to insulin detemir or NPH insulin as a basal insulin for 16 weeks, followed by the other basal insulin for 16 weeks. At the end of each 16-week period, total energy expenditure, resting energy expenditure, diet-induced thermogenesis, activity energy expenditure, energy intake, weight change, glycemic control, hypoglycemic episodes, and hormones that affect satiety and fuel partitioning were measured., Results: After 16 weeks, weight change was -0.69±1.85 kg with insulin detemir and +1.7±2.46 kg with NPH insulin (P<0.001). Total energy intake was significantly less with insulin detemir (2,016±501 kcal/day) than with NPH insulin (2,181±559 kcal/day) (P=0.026). There was no significant difference in any measure of energy expenditure, HbA1c percentage, or number of hypoglycemic episodes. Leptin was lower and resistin was higher with insulin detemir compared with NPH insulin (P=0.039, P=0.047). After the meal, ghrelin and pancreatic polypeptide levels (P=0.002, P=0.001) were higher with insulin detemir., Conclusions: The reduced weight gain with insulin detemir compared with NPH insulin is attributed to reduced energy intake rather than increased energy expenditure. This may be mediated by a direct or indirect effect of insulin detemir on the hormones that control satiety.

Type 1 diabetes is associated with abnormalities of the growth hormone (GH)-IGF-I axis. Such abnormalities include decreased circulating levels of IGF-I. We studied the effects of IGF-I therapy (40 microg x kg(-1) x day(-1)) on protein and glucose metabolism in adults with type 1 diabetes in a randomized placebo-controlled trial. A total of 12 subjects participated, and each subject was studied at baseline and after 7 days of treatment, both in the fasting state and during a hyperinsulinemic-euglycemic amino acid clamp. Protein and glucose metabolism were assessed using infusions of [1-13C]leucine and [6-6-2H2]glucose. IGF-I administration resulted in a 51% rise in circulating IGF-I levels (P < 0.005) and a 56% decrease in the mean overnight GH concentration (P < 0.05). After IGF-I treatment, a decrease in the overnight insulin requirement (0.26+/-0.07 vs. 0.17+/-0.06 U/kg, P < 0.05) and an increase in the glucose infusion requirement were observed during the hyperinsulinemic clamp (approximately 67%, P < 0.05). Basal glucose kinetics were unchanged, but an increase in insulin-stimulated peripheral glucose disposal was observed after IGF-I therapy (37+/-6 vs. 52+/-10 micromol x kg(-1) x min(-1), P < 0.05). IGF-I administration increased the basal metabolic clearance rate for leucine (approximately 28%, P < 0.05) and resulted in a net increase in leucine balance, both in the basal state and during the hyperinsulinemic amino acid clamp (-0.17+/-0.03 vs. -0.10+/-0.02, P < 0.01, and 0.25+/-0.08 vs. 0.40+/-0.06, P < 0.05, respectively). No changes in these variables were recorded in the subjects after administration of placebo. These findings demonstrated that IGF-I replacement resulted in significant alterations in glucose and protein metabolism in the basal and insulin-stimulated states. These effects were associated with increased insulin sensitivity, and they underline the major role of IGF-I in protein and glucose metabolism in type 1 diabetes.

IDDM is associated with elevated circulating levels of growth hormone (GH) and reduced insulin-like growth factor I (IGF-I). GH antagonizes the action of insulin-increasing insulin requirements in IDDM. The effects of subcutaneously administered rhIGF-I on glycemic control, insulin requirements, and GH secretion were studied in eight adults with IDDM. Patients received either placebo or rhIGF-I (50 microg/kg b.i.d.) for 19 days in a randomized, double-blind, parallel-design, placebo-controlled trial. Overnight GH, plasma glucose, free insulin, IGF-I, fructosamine, and lipid profiles were assessed during this period. rhIGF-I therapy increased IGF-I concentration from 117.1 +/- 14.2 (mean +/- SE) ng/ml (baseline) to 310.5 +/- 40.6 and 257.1 +/- 41.2 ng/ml on day 5 (P < 0.01 vs. baseline) and day 20 (P < 0.01 vs. baseline), respectively. After 19 days of rhIGF-I treatment, fructosamine concentrations were unchanged compared with baseline (439 +/- 32 vs. 429 +/- 35 micromol/l, day -1 vs. day 20, respectively), yet insulin requirements were decreased by approximately 45% (0.67 +/- 0.08 vs. 0.36 +/- 0.07 U x kg(-1) x day(-1), day -1 vs. day 19, respectively, P < 0.005). After 4 days of rhIGF-I therapy, there was a decrease in free insulin levels (8.38 +/- 1.47 vs. 4.98 +/- 0.84 mU/l, P < 0.05), mean overnight GH concentration (12.6 +/- 3.3 vs. 3.8 +/- 2.1 mU/l, P = 0.05), and total cholesterol and triglycerides (4.68 +/- 0.31 vs. 4.25 +/- 0.35 mmol/l, P < 0.05, 1.27 +/- 0.19 vs. 0.95 +/- 0.21 mmol/l, P < 0.001, respectively). There was no change in any variable in the placebo-treated patients. This study demonstrates that subcutaneous administration of rhIGF-I decreases insulin requirements and improves the plasma lipid profile while maintaining glycemic control in adults with IDDM. The excess nocturnal release of GH, characteristic of IDDM, is also decreased by rhIGF-I therapy.