Glucose Infusion Rate Research Articles

8721 A Case of Congenital Hyperinsulinism Manifesting as Transient Hypoglycemia During Illness Due to Mosaic Variant of Unknown Significance in ABCC8

Abstract Disclosure: E.E. Bell-Sambataro: None. L. Mamilly: None. Background: Congenital hyperinsulinism (CHI) is characterized by inappropriate secretion of insulin during periods of low blood glucose. CHI can lead to significant complications such as seizures, developmental delays and neurologic damage. CHI can be caused by multiple genetic variants. The most common genetic etiologies are loss of function mutations in the genes ABCC8 and KCNJ11 encoding the pancreatic Beta (β)-cell ATP-sensitive potassium channel causing over secretion of insulin from the β-cells. We report a challenging pediatric case with a clinical presentation of CHI in an infant with a de novo mosaic ABCC8 gene variant of unknown significance manifesting only during times of illness. Clinical Case: A male infant born at 36 weeks gestational age was transferred to a tertiary center NICU secondary to seizure activity and hypoglycemia after the 24 hours of life with glucose levels as low as 32 mg/dL. His birth weight was normal and there was not maternal history of diabetes mellitus. The hypoglycemia persisted throughout the first week of life and required a glucose infusion rate of 11 mg/kg/min, without success in obtaining a critical sample. He had multiple seizures and MRI brain showed signs of hypoglycemic encephalopathy. Subsequently, he was weaned off IV dextrose and completed a 6 hour safety fast prior to discharge. Rapid genome testing resulted in a de novo, mosaic variant of unknown significance in ABCC8 (C.3622G>A resulting in amino acid substitution p.Glu1208Lys). His family reported significant but transient hypoglycemia during times of illness. At the age of 11 months, he was hospitalized for significant hypoglycemia during an episode of acute gastroenteritis and was treated with dextrose-containing fluids for 36 hours. A subsequent diagnostic fasting study resulted in hypoglycemia within 5.5 hours with capillary glucose of 49 mg/dL. At the time of hypoglycemia, beta hydroxybutyrate was inappropriately low at 0.78 mm, insulin level was suppressed <2 mcIU/mL. Glucagon (30 mcg/Kg) was administered after the initial sample was drawn with a significant increase in glucose from 49 mg/dL to 103 mg/dL. Based on the positive glucagon response and low serum ketone, the clinical diagnosis of CHI was made and diazoxide was initiated while awaiting other results. After the second dose of diazoxide, all glucose levels remained above 80 mg/dL. He was sent home on a continuous glucose monitor and diazoxide. Conclusion: CHI can occur due to autosomal recessive or autosomal dominant ABCC8 loss-of-function mutations of which more than half are not responsive to diazoxide. In this case report, we describe the diagnosis of hyperinsulinemic hypoglycemia in an infant with an ABCC8 variant classified with unknown significance. We describe a good initial response to diazoxide in normalizing blood glucose levels in this infant. Presentation: 6/2/2024

A comparative evaluation of bioequivalence of Gan & Lee glargine U300 and Toujeo® in Chinese healthy male participants.

To assess the bioequivalence between Gan & Lee (GL) glargine U300 and Toujeo® regarding pharmacokinetics (PK), pharmacodynamics (PD), and safety in Chinese healthy male participants. A single-center, randomized, double-blind, single-dose, two-preparation, two-sequence, four-cycle repeated crossover design study was performed to compare GL glargine U300 and Toujeo® in 40 healthy participants. The primary PK endpoints were the area under the curve of glargine metabolites, M1 concentration from 0 to 24 hours (AUC0-24h), and the maximum glargine concentration within 24 hours post-dose (Cmax). The primary PD endpoints were the area under the glucose infusion rate (GIR) curve from 0 to 24 hours (AUCGIR.0-24h) and the maximum GIR within 24 hours post-dose (GIRmax). GL Glargine U300 demonstrated comparable PK parameters (AUC0-24h, Cmax, AUC0-12h, and AUC12-24h of M1) and PD responses [AUCGIR.0-24h, GIRmax, AUCGIR.0-12h, and AUCGIR.12-24h] to those of Toujeo®, as indicated by 90% confidence intervals ranging from 80% to 125%. No significant disparities in safety profiles were observed between the two treatment groups, and there were no reported instances of serious adverse events. The PK, PD, and safety of GL glargine U300 were bioequivalent to that of Toujeo®. https://www.chinadrugtrials.org.cn/, identifier CTR20212419.

Sleep Duration Alters Overfeeding-mediated Reduction in Insulin Sensitivity.

Weight gain and sleep restriction both reduce insulin sensitivity. However, it is not known if sleep duration alters glucose metabolism in response to overfeeding. To examine the effect of sleep duration on overfeeding-mediated alterations in carbohydrate metabolism and insulin sensitivity. Retrospective exploratory analysis of a longitudinal overfeeding study in healthy participants (n = 28, age: 26.9 ± 5.5 years, body mass index: 25.74 ± 2.45 kg/m2). After providing baseline study measures, participants were overfed 40% above weight maintenance calorie requirements for 8 weeks. Insulin sensitivity was determined by a 2-step hyperinsulinemic-euglycemic clamp. Baseline habitual sleep duration was estimated by accelerometry, and sleep groups were created based on median sleep duration (5.2 hours/night). Overfeeding led to an average body weight gain of 7.3 ± .4 kg. Habitual sleep duration did not alter overfeeding-mediated body weight gain, fat gain, and fat distribution (all P > .15). Compared to participants with more sleep, fasting insulin (P = .01) and homeostatic model assessment for insulin resistance (P = .02) increased while fasting glucose remained unchanged (P = .68) with overfeeding in participants with shorter sleep duration. Glucose infusion rate during high insulin dose was reduced with overfeeding in participants with short sleep duration but not in participants with more sleep (P < .01). Overfeeding mediated weight gain reduced liver, adipose, and whole-body insulin sensitivity prominently in individuals with short sleep duration but not in individuals with longer sleep duration. This suggests that promoting adequate sleep during short periods of overeating may prevent detrimental effects on glucose metabolism.

α- or β-Adrenergic blockade does not affect transplanted islet cell responses to hypoglycemia in type 1 diabetes.

Type 1 diabetes recipients of intrahepatic islet transplantation exhibit glucose-dependent suppression of insulin and activation of glucagon secretion in response to insulin-induced hypoglycemia associated with clinical protection from hypoglycemia. Whether sympathetic activation of adrenergic receptors on transplanted islets is required for these responses in defense against hypoglycemia is not known. To evaluate the adrenergic contribution to posttransplant glucose counterregulation, we performed a randomized, double-blind crossover study of responses during a hyperinsulinemic euglycemic-hypoglycemic clamp under phentolamine (α-adrenergic blockage), propranolol (β-adrenergic blockage), or placebo infusion. Characteristics of participants (5 females/4 males) were as follows: median (range) age 53 (34-63) yr, diabetes duration 29 (18-56) yr, posttransplant 7.0 (1.9-8.4) yr, HbA1c 5.8 (4.5-6.8)%, insulin in-/dependent 5/4, all on tacrolimus-based immunosuppression. During the clamp, blood pressure was lower with phentolamine and heart rate was lower with propranolol versus placebo (P < 0.05). There was no difference in the suppression of endogenous insulin secretion (derived from C-peptide measurements) during the euglycemic or hypoglycemic phases, and although levels of glucagon were similar with phentolamine or propranolol vs. placebo, the increase in glucagon from eu- to hypoglycemia was greater with propranolol vs. placebo (P < 0.05). Pancreatic polypeptide was greater with phentolamine versus placebo during the euglycemic phase (P < 0.05), and free fatty acids were lower and the glucose infusion rate was higher with propranolol versus placebo during the hypoglycemic phase (P < 0.05 for both). These results indicate that neither physiological α- nor β-adrenergic blockade attenuates transplanted islet responses to hypoglycemia, suggesting sympathetic reinnervation of the islet graft is not necessary for posttransplant glucose counterregulation.NEW & NOTEWORTHY Whether adrenergic input to islets is necessary for glucose homeostasis in humans is debated. Here, the adrenergic contribution to intrahepatically transplanted islet cell responses to hypoglycemia in individuals with type 1 diabetes was investigated through α- or β-adrenergic receptor blockade during hyperinsulinemic euglycemic-hypoglycemic clamps. Neither α- nor β-adrenergic blockage affected the suppression of endogenous insulin or activation of glucagon secretion, suggesting that sympathetic reinnervation of islet grafts is not required for posttransplant defense against hypoglycemia.

Long term administration of thiamine disulfide improves FOXO1/PEPCK pathway in liver to reduce insulin resistance in type 1 diabetes rat model

ObjectiveThe main objective of this study was to find if thiamine disulfide (TD) lowers blood glucose level and improves insulin resistance (IR) in liver and muscle in rats with chronic type 1 diabetes (T1DM) using euglycemic-hyperinsulinemic clamp technique. MethodsA total of fifty male Wistar rats were assigned to five groups consisted of: non-diabetic control (NDC), diabetic control (DC), diabetic treated with thiamine disulfide (D-TD), diabetic treated with insulin (D-insulin), and diabetic treated with both TD and insulin (D-insulin+TD). Diabetes was induced by a 60 mg/kg dose of streptozotocin. Blood glucose levels, pyruvate tolerance test (PTT), intraperitoneal glucose tolerance test (IPGTT), levels of glycosylated hemoglobin (HbA1c), glucose infusion rate (GIR), liver and serum lipid profiles, liver glycogen stores, liver enzymes ([ALT], [AST]), and serum calcium and magnesium levels. were evaluated. Additionally, gene expression levels of phosphoenolpyruvate carboxykinase (Pepck), forkhead box O1 (Foxo1), and glucose transporter type 4 (Glut4) were assessed in liver and skeletal muscle tissues. ResultsBlood glucose level was reduced by TD treatment. In addition, TyG index, HOMA-IR, serum and liver lipid profiles, HbA1c levels, and expressions of Foxo1 and Pepck genes were decreased significantly (P<0.05) in all the treated groups. However, TD did not influence Glut4 gene expression, but GIR as a critical index of IR were 5.0±0.26, 0.29±0.002, 1.5±0.07, 0.9±0.1 and 1.3±0.1 mg.min−1Kg−1 in NDC, DC, D-TD, D-insulin and D-insulin+TD respectively. ConclusionsTD improved IR in the liver primarily by suppressing gluconeogenic pathways, implying the potential use of TD as a therapeutic agent in diabetes.

Daily standing time, dietary fiber, and intake of unsaturated fatty acids are beneficially associated with hepatic insulin sensitivity in adults with metabolic syndrome.

Obesity is associated with impaired glucose metabolism and hepatic insulin resistance. The aim was to investigate the associations of hepatic glucose uptake (HGU) and endogenous glucose production (EGP) to sedentary behavior (SB), physical activity (PA), cardiorespiratory fitness, dietary factors, and metabolic risk markers. Forty-four adults with metabolic syndrome (mean age 58 [SD 7] years, BMI ranging from 25-40kg/; 25 females) were included. HGU was measured by positron emission tomography during the hyperinsulinemic-euglycemic clamp. EGP was calculated by subtracting the glucose infusion rate during clamp from the glucose rate of disappearance. SB and PA were measured with hip-worn accelerometers (26 [SD3] days). Fitness was assessed by maximal bicycle ergometry with respiratory gas measurements and dietary intake of nutrients by 4-day food diaries. HGU was not associated with fitness or any of the SB or PA measures. When adjusted for sex, age, and body fat-%, HGU was associated with whole-body insulin sensitivity (β=0.58), water-insoluble dietary fiber (β=0.29), energy percent (E%) of carbohydrates (β=-0.32), saccharose (β=-0.32), mono- and polyunsaturated fatty acids (β=0.35, β=0.41, respectively). EGP was associated with whole-body insulin sensitivity (β=-0.53), and low-density lipoprotein cholesterol [β=-0.31], and when further adjusted for accelerometry wear time, EGP was associated with standing [β=-0.43]. (p-value for all< 0.05). Standing more, consuming a diet rich in fiber and unsaturated fatty acids, and a lower intake of carbohydrates, especially sugar, associate beneficially with hepatic insulin sensitivity. Habitual SB, PA, or fitness may not be the primary modulators of HGU and EGP. However, these associations need to be confirmed with intervention studies.

High Fat Feeding Blunts Skeletal Muscle Oxygen Mediated Blood Flow Responses in Healthy and Type 2 Diabetic Rats

Hypothesis: High fat diet feeding impairs microvascular blood flow responses to dynamic changes in local oxygen concentration ([O2]) in Sprague-Dawley (SD) and Zucker Diabetic Sprague-Dawley (ZDSD) rats. Methods: Seven-week-old male SD and ZDSD rats were fed either a standard chow (N = 7 SD, 5 ZDSD) or a high saturated fat diet (N = 8 SD, 6 ZDSD) for 7 weeks. At 14 weeks of age animals were anaesthetized, instrumented for systemic monitoring, and mechanically ventilated. The extensor digitorum longus muscle was blunt dissected and reflected over a gas exchange chamber imbedded in the stage of an inverted microscope. Microvascular blood flow responses to high and low [O2] challenges (7 – 12 %, and 7 – 2 %) and sequential changes in [O2] (7 – 12 – 2 – 7 %) were recorded at baseline and during hyperinsulinemic-euglycemic clamp. Gas conditions within the chamber were set at 7 % for a 1-minute baseline followed by 2 minutes at either 2 or 12 % O2. The 4-minute square wave oscillation consisted of 1 minute at each [O2] (7 – 12 – 2 – 7 %). Hyperinsulinemic-euglycemic clamp was achieved by simultaneous infusion of insulin (2 U/hr/kg) and variable rate of 50 % glucose until euglycemia was reached (5 - 7 mM blood glucose). Analysis of intravital videos was completed using custom MATLAB software. All animal protocols were approved by Memorial University’s Animal Care Committee. Results: Chow fed SD had significantly higher glucose infusion rates compared to high fat fed SD, chow fed ZDSD, and high fat fed ZDSD (28.11 ± 1.807 vs. 25.14 ± 1.18, 24.56 ± 2.78, 24.77 ± 2.43 mg/kg/min, p = 0.0429, 0.0305, 0.0323, respectively). Red blood cell (RBC) saturation significantly increased and decreased in all groups within 4 s following the increase and decrease in [O2], respectively. Chow fed SD had significant decrease in RBC supply rate (SR) in response to 12 % [O2] (10.41 ± 11.31 vs 7.44 ± 8.40 cells/s, p &lt; 0.0001, τ = 15.85 s). In response to low [O2], significant increases in SR were measured in the chow fed SD and ZDSD groups (7.10 ± 8.76 vs 11.65 ± 11.36 cells/s, p &lt; 0.0001, τ = 17.65 s, and 10.86 ± 13.62 vs 13.86 ± 14.69 cells/s, p &lt; 0.0001, τ = 85.74 s, respectively). High fat fed SD and ZDSD had significant increases in RBC SR during 2 % [O2] (8.47 ± 9.75 vs 11.84 ± 12.11 cells/s, p &lt; 0.0001, τ = 68.49 s, and 16.09 ± 18.12 vs 20.73 ± 21.92 cells/s, p &lt; 0.0001, τ = 23.98 s). High fat fed ZDSD had higher, but not significantly different, baseline RBC SR compared to the chow fed ZDSD group. Chow fed SD were the only group to have an increase in RBC SR at low [O2] during hyperinsulinemic-euglycemic clamp (13.80 ± 17.78 vs 18.07 ± 20.25 cells/s, p = 0.0003, τ = 10.88 s). Conclusions: High fat feeding impairs the capillary blood flow response to local increases in [O2] in healthy and high fat fed T2D model rats. Chow fed ZDSD rats had slower capillary blood flow dynamics than the SD control group. Hyperinsulinemic-euglycemic clamp diminishes the O2 mediated blood flow response in 14-week-old SD and ZDSD rats fed a high fat diet. This project was supported by the Canadian Institute of Health Research through a project grant to GMF. Studentships were supported by Memorial University's School of Graduate Studies and the Faculty of Medicine. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Vietnam National Survey on Parenteral Nutrition Practice in Preterm Neonates: Practice Status, Barriers, and Implications.

Due to high risks of feeding intolerance, preterm infants often receive parenteral nutrition (PN) to ensure sufficient nutrition and energy intake. However, there is a lack of data on the status of clinical PN practice and barriers among neonatal care units in low- to middle-income countries like Vietnam. This extensive survey explores the status and barriers of PN practice for preterm infants in neonatal units across Vietnam and identifies the practical implications of enhancing nutritional outcomes in preterm infants. A multicenter nationwide web-based survey on PN practice in preterm infants was conducted across 114 neonatal units from 61 provinces in Vietnam. Among 114 neonatal units receiving a request for surveys, 104 units (91.2%) from 55 provinces participated. Neonatal units were categorized as level I (2/104, 1.9%), II (39/104, 37.5%), III (56/104, 53.8%), and IV (7/104, 6.8%). We found that the initiations of PN within the first hour and the first two hours of life occurred in 80.8% (84/104) and 95.2% (99/104) of the units, respectively. The early provision of amino acids, or AA (within the first day of life) and lipids (within two days of life) were documented by 85% (89/104) and 82% (84/104) of the respondents, respectively. The initial dose of AA ranged from 0.5 to 3 g/kg/day; the dose of AA less than 1 g/kg/day was reported by 7.7% (8/104) of the respondents; the maximum dose of AA ranged from 2 to over 4.5 g/kg/day, with 4 g/kg/day reported by 47.1% (49/104) of the respondents. The initial dose of lipids was between 0.5 and 2 g/kg/day, frequently 1 g/kg/day, reported by 51.9% (54/104) of the respondents; the target lipid dose ranged from 3 to 4 g/kg/day in 93.3% (97/104) respondents; the maximum target dose for lipid was 4 g/kg/day in 36.5% (38/104) of the respondents. The initial glucose dose was distributed as follows: 46.2% of respondents (48/104) administered 4 mg/kg/minute, 21.2% (22/104) used 5 mg/kg/minute, 28.8% (30/104) used 6 mg/kg/minute, and 3.8% (4/104) used 3 mg/kg/minute. Additionally, 48.1% of respondents (50/104) reported a maximum glucose infusion rate above 13 mg/kg/min and 19.2% (20/104) above 15 mg/kg/min. Nineteen percent (20/104) of the respondents reported a lack of micronutrients. Barriers to PN initiation included difficulty in establishing intravenous lines, the absence of standardized protocols, the lack of lipids and micronutrients, infections, and unavailable software supporting neonatologists in calculating nutrition paradigms. This study's findings highlight the highly variable PN practice across neonatal units in Vietnam. Deviations from current practical guidelines can be explained by various barriers, most of which are modifiable. A monitoring network for nutritional practice status and a database to track the nutritional outcomes of preterm infants in Vietnam are needed.

Muscle-specific Asah1 knockout mice develop whole-body insulin resistance

Skeletal muscle is a major tissue for glucose and lipid metabolism. Increasing ectopic deposition of lipid species is often found in obese populations, and this has been associated with the development of insulin resistance. Sphingolipids, particularly ceramides (Cer), are bioactive lipid species, and their accumulation in metabolically active tissues has been shown to desensitize insulin action. For example, using palmitate or Cer analogues in C2C12 or L6 myotubes increases long chain Cer accumulation in the myotubes and inhibits insulin-stimulated Akt phosphorylation. Moreover, inhibiting Cer synthesis improves insulin stimulated glucose uptake in obese rats and mice. However, genetic approaches to evaluating ceramide's effects have been limited to in vitro system and the effects of Cer in skeletal muscle on energy metabolism remain unprobed. Here, we developed and utilized a genetically modified mouse model to induce endogenous Cer accumulation in selectively in skeletal muscle to determine the effects of Cer accrual in skeletal muscle metabolism. Mice were fed high-fat diet (HFD) for 30-day or 60-day. Thirty-day diet intervention significantly increased muscle Cer, which returned to the baseline after 60-days of HFD. We found the expression of acid ceramidase ( Asah1) gene, which is responsible for degrading Cer, was highly elevated only in skeletal muscle from mice fed 30- and 60-day HFD, indicating Asah1 may be an important regulator of muscle ceramides. In order to probe the effect of Asah1 expression on muscle metabolism, we generated tamoxifen-inducible muscle-specific Asah1 knockout mice (Asah1MKO) and provided HFD for 20 weeks. There was no difference in bodyweight between control littermates (Asah1fl/fl) and Asah1MKO during the intervention. We confirmed that Asah1MKO mice significantly increased muscle Cer contents compared to Asah1fl/fl controls. At 18-week of HFD feeding, mice from both groups were tested for insulin and glucose tolerance, but there was no change between the groups. Finally, the mice were tested by hyperinsulinemic-euglycemic clamp to determine whether increased muscle Cer affects whole-body insulin sensitivity. Interestingly, we found that HFD-fed Asah1MKO mice dramatically reduced glucose infusion rate required to maintain euglycemia and blunt 2-deoxyglucose uptake into skeletal muscle compared to controls. These data suggest that Cer accrual in skeletal muscle can be a major contributor to whole-body insulin resistance. In summary, we found that Asah1 is increased only in skeletal muscle in response to HFD, and knocking out Asah1 in mouse skeletal muscle impairs whole-body insulin sensitivity, suggesting that the levels of muscle Cer are potentially critical in the development of insulin resistance. This research work was supported by the National Institute of Health grant (R01DK115824). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Clinical Pharmacology of GP40321 (Insulin Glulisine Biosimilar): Pharmacokinetic and Pharmacodynamic Comparability in a Hyperinsulinemic-Euglycemic Clamp Procedure.

The aim of the study was to compare the pharmacokinetics (PK) and pharmacodynamics (PD) of T-glu (GP40321, test drug), and reference insulin glulisine in a hyperinsulinemic-euglycemic clamp procedure. During this study, 34 healthy male volunteers underwent the hyperinsulinemic-euglycemic clamp procedure following subcutaneous 0.3U/kg injection of T-glu or reference insulin glulisine in a randomized, double-blind, crossover study. Plasma glucose levels were monitored every 5minutes for 8hours. Glucose infusion rate adjustment was based on the blood glucose measurements. Evaluation of PD was performed using the glucose infusion rate values, while PK was calculated using insulin concentrations measured via enzyme-linked immunosorbent assay. The study results showed that the 90% CI for the geometric mean ratios of primary PK and PD of T-glu and reference insulin glulisine were within 80%-125% comparability limits, and that the safety profiles were comparable. PK, PD, and safety similarity of T-glu and reference insulin glulisine was demonstrated.

Role of human Kallistatin in glucose and energy homeostasis in mice

ObjectiveKallistatin (KST), also known as SERPIN A4, is a circulating, broadly acting human plasma protein with pleiotropic properties. Clinical studies in humans revealed reduced KST levels in obesity. The exact role of KST in glucose and energy homeostasis in the setting of insulin resistance and type 2 diabetes is currently unknown. MethodsKallistatin mRNA expression in human subcutaneous white adipose tissue (sWAT) of 47 people with overweight to obesity of the clinical trial “Comparison of Low Fat and Low Carbohydrate Diets With Respect to Weight Loss and Metabolic Effects (B-SMART)” was measured. Moreover, we studied transgenic mice systemically overexpressing human KST (hKST-TG) and wild type littermate control mice (WT) under normal chow (NCD) and high-fat diet (HFD) conditions. ResultsIn sWAT of people with overweight to obesity, KST mRNA increased after diet-induced weight loss. On NCD, we did not observe differences between hKST-TG and WT mice. Under HFD conditions, body weight, body fat and liver fat content did not differ between genotypes. Yet, during intraperitoneal glucose tolerance tests (ipGTT) insulin excursions and HOMA-IR were lower in hKST-TG (4.42 ± 0.87 AU, WT vs. 2.20 ± 0.27 AU, hKST-TG, p < 0.05). Hyperinsulinemic euglycemic clamp studies with tracer-labeled glucose infusion confirmed improved insulin sensitivity by higher glucose infusion rates in hKST-TG mice (31.5 ± 1.78 mg/kg/min, hKST-TG vs. 18.1 ± 1.67 mg/kg/min, WT, p < 0.05). Improved insulin sensitivity was driven by reduced hepatic insulin resistance (clamp hepatic glucose output: 7.7 ± 1.9 mg/kg/min, hKST-TG vs 12.2 ± 0.8 mg/kg/min, WT, p < 0.05), providing evidence for direct insulin sensitizing effects of KST for the first time. Insulin sensitivity was differentially affected in skeletal muscle and adipose tissue. Mechanistically, we observed reduced Wnt signaling in the liver but not in skeletal muscle, which may explain the effect. ConclusionsKST expression increases after weight loss in sWAT from people with obesity. Furthermore, human KST ameliorates diet-induced hepatic insulin resistance in mice, while differentially affecting skeletal muscle and adipose tissue insulin sensitivity. Thus, KST may be an interesting, yet challenging, therapeutic target for patients with obesity and insulin resistance.

Factors associated with neonatal hyperinsulinemic hypoglycemia, a case-control study.

We aimed to identify perinatal risk factors associated with hyperinsulinemic hypoglycemia in neonates. Secondary objectives included an examination of clinical and biochemical characteristics at the time of diagnosis and an exploration of the duration of diazoxide therapy. A case-control study was conducted, involving individual chart reviews of inborn infants diagnosed with hyperinsulinemic hypoglycemia (the HH group) between 2014 and 2021. These cases were paired with controls (the non-HH group) belonging to the same gestational age (GA) strata who did not exhibit HH or only had transient postnatal hypoglycemia. A total of 52 infants with HH were matched with corresponding controls. The mean GA in the HH group was 34.4±3.1weeks. Notably, the HH group exhibited lower mean minimum plasma glucose (PG) levels and required higher glucose infusion rates in comparison to the non-HH group (26.5±15.6 vs. 49.1±37.7 mg/dL and 12.9±3.8 vs. 5.7±2.1 mg/kg/min, respectively; p<0.001 for both). After adjusting for potential confounding factors, only two variables, fetal growth restriction (FGR) and neonatal sepsis, demonstrated significant associations with HH (adjusted odds ratio [95 % confidence interval]: 8.1 [2.1-31.0], p=0.002 and 6.3 [1.9-21.4], p=0.003, respectively). The median duration of diazoxide therapy for the HH group was 4months. FGR and neonatal sepsis emerged as notable risk factors for HH. These infants exhibited lower PG levels and necessitated higher glucose infusion rates compared to their non-HH counterparts. Importantly, a substantial proportion of the HH group received diazoxide therapy, with a median treatment duration of 4months.

Electroacupuncture improving obesity-induced insulin resistance via regulating intestinal SIRT1/TLR4 signaling pathway.

To observe the effect of electroacupuncture (EA) in obese rats with insulin resistance (IR) through regulating intestinal silent information regulator 1 (SIRT1)/Toll-like receptor 4 (TLR4) signaling pathway, so as to explore the underlying mechanism of EA in improving obesity-induced IR. A total of 40 Wistar rats were randomly divided into 4 groups, i.e. normal group, model group, EA group and EA combined with inhibitor group, with 10 rats in each group. The obesity-induced IR model was induced by feeding high-fat diet for 8 weeks. EA (2 Hz, 1mA) was applied at "Zhongwan"(CV12), "Guanyuan"(CV4), "Zusanli"(ST36) and "Fenglong" (ST40) for 10 min, 3 times a week for 8 weeks in both EA and EA combined with inhibitor groups. Sirtinol, an inhibitor of SIRT1 was injected into the tail vein (1 mg/kg), 3 times a week for 8 weeks in EA combined with inhibitor group. The body weight, glucose infusion rate (GIR) of rats in each group were recorded. The contents of serum C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and lipopolysaccharide (LPS) were detected by ELISA. Mucosal morphological changes in the small intestine was observed by HE staining and was graded using Chiu's score. The protein relative expression levels of SIRT1 and TLR4 and the co-labeling of SIRT1 with TLR4 in the small intestine was detected by Western blot and double immunofluorescence staining, separately. Compared with the normal group, the body weight, serum contents of CRP, TNF-α, IL-6, LPS, Chiu's score, TLR4 protein relative expression level and percentage of TLR4 positive expression area were increased (P<0.01, P<0.05), while the GIR, SIRT1 protein expression, percentage of SIRT1 positive expression area and SIRT1/TLR4 were decreased (P<0.01) in the model group. The pathological injury of small intestine mucosa was severe, accompanied with inflammatory cell infiltration in the model group. Following interventions, the body weight, serum contents of CRP, TNF-α and LPS, Chiu's score, TLR4 protein relative expression level and percentage of TLR4 positive expression area were decreased(P<0.01, P<0.05), and the GIR was increased (P<0.01), the pathological injury and inflammatory cell infiltration of small intestine mucosa were reduced in both EA and EA combined with inhibitor groups in contrast to the model group. Compared with the model group, the serum IL-6 content was significantly decreased (P<0.01), and the SIRT1 protein relative expression level and percentage of positive expression area, SIRT1/TLR4 were increased (P<0.01, P<0.05) in the EA group. Compared with the EA group, EA combined with inhibitor group showed the body weight, serum CRP, IL-6, LPS, Chiu's score, TLR4 protein relative expression level and TLR4 positive expression area were increased (P<0.01, P<0.05), and the GIR level , SIRT1 relative expression level, SIRT1/TLR4 ratio were decreased (P<0.05, P<0.01). EA can reduce the body weight and ameliorate peripheral insulin sensitivity in IR obese rats, which may be related with its function in regulating intestinal SIRT1/TLR4 signaling pathway to reduce inflammatory response.

Oral magnesium supplementation does not affect insulin sensitivity in people with insulin-treated type 2 diabetes and a low serum magnesium: a randomised controlled trial

Aims/hypothesisHypomagnesaemia has been associated with insulin resistance and an increased risk of type 2 diabetes. Whether magnesium supplementation improves insulin sensitivity in people with type 2 diabetes and a low serum magnesium level is unknown.MethodsUsing a randomised, double-blind (both participants and investigators were blinded to the participants’ treatment sequences), placebo-controlled, crossover study design, we compared the effect of oral magnesium supplementation (15 mmol/day) for 6 weeks with that of matched placebo in individuals with insulin-treated type 2 diabetes (age ≥18 years, BMI 18–40 kg/m2, HbA1c <100 mmol/mol [11.3%], serum magnesium ≤0.79 mmol/l). Participants were recruited from the outpatient clinic and through advertisements. Randomisation to a treatment sequence order was done using a randomisation list. We used block randomisation and the two possible treatment sequences were evenly distributed among the trial population. The primary outcome was the mean glucose infusion rate during the final 30 min of a hyperinsulinaemic–euglycaemic clamp (i.e. M value). Secondary outcomes included variables of glucose control, insulin need, BP, lipid profile and hypomagnesaemia-related symptoms during follow-up.ResultsWe recruited 14 participants (50% women, 100% White, mean ± SD age 67±6 years, BMI 31±5 kg/m2, HbA1c 58±9 mmol/mol [7.4±0.9%]) with insulin-treated type 2 diabetes. Magnesium supplementation increased both mean ± SEM serum magnesium level (0.75±0.02 vs 0.70±0.02 mmol/l, p=0.016) and urinary magnesium excretion (magnesium/creatinine ratio, 0.23±0.02 vs 0.15±0.02, p=0.005), as compared with placebo. The M value of the glucose clamp did not differ between the magnesium and placebo study arms (4.6±0.5 vs 4.4±0.6 mg kg−1 min−1, p=0.108). During the 6 weeks of treatment, continuous glucose monitoring outcomes, HbA1c, insulin dose, lipid profile and BP also did not differ, except for a lower HDL-cholesterol concentration after magnesium compared with placebo (1.14±0.08 vs 1.20±0.09 mmol/l, p=0.026). Symptoms potentially related to hypomagnesaemia were similar for both treatment arms.Conclusions/interpretationDespite an albeit modest increase in serum magnesium concentration, oral magnesium supplementation does not improve insulin sensitivity in people with insulin-treated type 2 diabetes and low magnesium levels.Trial registrationEudraCT number 2021-001243-27.FundingThis study was supported by a grant from the Dutch Diabetes Research Foundation (2017–81–014).Graphical

Thyroid-stimulating hormone may participate in insulin resistance by activating toll-like receptor 4 in liver tissues of subclinical hypothyroid rats.

Thyroid-stimulating hormone (TSH) is an independent risk factor of and closely associated with metabolic disorders. In the present study, we explored the potential mechanism and adverse effects of TSH on insulin resistance in the liver of subclinical hypothyroidism models in vivo. The mean glucose infusion rate (GIR), free fatty acids (FFAs), the homeostatic model assessment for insulin resistance (HOMA-IR), fasting plasma insulin (FINS), the TLR4 signal pathway and its intracellular negative regulator-toll-interacting protein (Tollip), and the modulators of insulin signaling were evaluated. Compared to the normal control group (NC group), the subclinical hypothyroidism rat group (SCH group) showed decreases in GIR and increases in FFAs, FINS, and HOMA-IR. The levels of TLR4 and of its downstream molecules like p-NF-κB, p-IRAK-1, IL-6 and TNF-α were evidently higher in the SCH group than in the NC group. Conversely, the level of Tollip was significantly lower in the SCH group than in the NC group. Compared to the NC group, the levels of phosphorylated IRS-1-Tyr and GLUT2 were decreased in the SCH group. Macrophage infiltration was higher in the SCH group than in the NC group. TSH may participate in aggravating inflammation by increasing macrophage infiltration; furthermore, it may activate the TLR4-associated inflammatory signaling pathway, thus interfering with insulin signals in liver tissues. Targeting TSH may have therapeutic benefits against metabolic disorders.

Evaluation and management of neonatal onset hyperinsulinemic hypoglycemia: a single neonatal center experience

Objectives To evaluate the clinical characteristics and treatment options of neonates requiring prolonged hospitalization due to persistent hyperinsulinemic hypoglycemia (HH). Methods This retrospective cohort study included infants >34 weeks of gestation at birth who were born in our hospital between 2018 and 2021, diagnosed with HH, and required diazoxide within the first 28 days of life. The baseline clinical characteristics, age at the time of diagnosis and treatment options in diazoxide resistance cases were recorded. Genetic mutation analysis, if performed, was also included. Results A total of 32 infants diagnosed with neonatal HH were followed up. Among the cohort, 25 infants were classified as having transient form of HH and seven infants were classified as having congenital hyperinsulinemic hypoglycemia (CHI). Thirty-one percent of the infants had no risk factors. The median birth weight was significantly higher in the CHI group, whereas no differences were found in other baseline characteristics. Patients diagnosed with CHI required higher glucose infusion rate, higher doses, and longer duration of diazoxide treatment than those in the transient HH group. Eight patients were resistant to diazoxide, and six of them required treatment with octreotide and finally sirolimus. Sirolimus prevented the need of pancreatectomy in five of six patients without causing major side effects. Homozygous mutations in the ABCC8 gene were found in four patients with CHI. Conclusions The risk of persistent neonatal hyperinsulinism should be considered in hypoglycemic neonates particularly located in regions with high rates of consanguinity. Our study demonstrated sirolimus as an effective treatment option in avoiding pancreatectomy in severe cases.

Relationship between rate of glucose or propionate infusion and milk protein yield and concentration in dairy cows: A meta-regression

Although postruminal glucose infusion into dairy cows has increased milk protein yield in some past experiments, the same trend has not been observed in others. A meta-regression of 64 sets of observations from 29 previously published glucose and propionate infusion studies in dairy cattle, treating study and experiment (study) as random effects, was performed to establish the general effects of glucose equivalent (GlcE) infusion rate on milk true protein (MTP) yield and content, if any, and to identify independent, fixed-effect variables that accounted for the changes in MTP yield and content that were observed. Candidate explanatory variables included rate and site of infusion, diet composition and intake, body weight and lactation stage of the cows, and the change in nutrient intake between GlcE and control treatments. Across all studies, according to a model containing only the random effects of study and experiment, GlcE infusion at an average of 954 g/d increased MTP yield by 26 g/d, on average, whereas mean MTP content was not affected. Backward stepwise elimination of potential explanatory variables from a full mixed model produced a final, reduced model for MTP yield that retained a positive, second-order quadratic effect of infusion rate of GlcE and a positive, linear effect of the change in crude protein intake (CPI) between GlcE treatment and control. This change in CPI due to GlcE infusion ranged from -0.546 to 0.173 kg/d in the dataset. The model fit indicated that when CPI was allowed to drop during GlcE infusion, the effect of GlcE on MTP yield was smaller than when CPI was maintained or increased, in a manifestation of the classic protein:energy interaction. The final reduced model for MTP content contained the same explanatory variables as for MTP yield, plus a negative effect of intravenous compared with gastrointestinal infusion. Overall, the meta-analysis revealed that both MTP yield, and content were positively related to GlcE infusion rate and to the change in CPI between glucose treatment and control.

OR12-04 LEAP2 Deletion Does Not Counteract The Effects Of Ghrelin Deletion During Insulin-Induced-Hypoglycemia

Abstract Disclosure: K. Shankar: None. S. Varshney: None. D. Gupta: None. O. Singh: None. S.B. Ogden: None. S. Osborne-Lawrence: None. N.P. Metzger: None. C.P. Richard: None. J.M. Zigman: Grant Recipient; Self; Novo Nordisk. Objective: The hormones ghrelin and LEAP2 both are endogenous ligands for the growth hormone secretagogue receptor (GHSR). Whereas ghrelin activates GHSR, LEAP2 blocks ghrelin from activating GHSR and also inhibits GHSR constitutive activity. It is via GHSR that the glucoregulatory actions of ghrelin and LEAP2 are mediated. These glucoregulatory actions are highlighted by the findings of severe hypoglycemia in ghrelin-KO mice and LEAP2-overexpressing mice when they are submitted to an acute-on-chronic caloric restriction protocol. Also, recently, our group showed that ghrelin-KO mice require a much higher glucose infusion rate (GIR) and exhibit markedly reduced elevation of counterregulatory hormones when submitted to a hyperinsulinemic-hypoglycemic clamp. In the current study, we investigated the potential of LEAP2 to protect against insulin-induced-hypoglycemia and counteract the effects of ghrelin deletion during the hypoglycemic clamp. Methods: Eight-ten week-old male wild-type (WT), Ghrelin-KO, LEAP2-KO, and LEAP2/Ghrelin-doubleKO (lacking both ghrelin and LEAP2 ) littermates were used for this study (n=7-10 per genotype). Mice were implanted with a right jugular vein catheter. Five days later, hyperinsulinemic-hypoglycemic clamps were performed in conscious, unrestrained mice. A low dose of insulin was infused at 4 mU/kg/min i.v. over 2 hr. A 20% glucose solution was simultaneously infused at a variable rate to achieve hypoglycemia (35–45 mg/dL) during the final 30 min. Blood glucose was measured via tail nicks every 5 min. Results: We were able to achieve the target hypoglycemic range in all four genotypes using this protocol. As compared to WT mice, Ghrelin-KO mice required markedly elevated (∼110% higher) GIRs (10±4 mg/kg/min in WT vs. 22±2 mg/kg/min in Ghrelin-KO mice; p=0.03) by the end of the 2-hr clamp. The GIRs required by LEAP2-KO mice were equivalent to those of WT mice (7±2 mg/kg/min in LEAP2-KO; p=n.s.). Furthermore, although during the first 60 min of the clamp, LEAP2/Ghrelin-doubleKO mice exhibited slightly lower blood glucose levels than the other genotypes and during the middle 60 min of the clamp, they required higher GIRs than the other genotypes, by the end of the 2-hr clamp, their GIRs were similar to Ghrelin-KO mice (25±3 mg/Kg/min in Ghrelin/LEAP2-doubleKO mice, p=n.s.). Conclusions: These data suggest a complex effect of LEAP2 on blood glucose. Alone, LEAP2 deletion does not impact insulin sensitivity. When coupled with ghrelin deletion, LEAP2 deletion lowers fasting blood glucose and causes greater insulin sensitivity early on during the hyperinsulinemic-hypoglycemic clamp. By the end of the clamp, this effect of LEAP2 deletion when coupled to ghrelin deletion is gone. Altogether, these results suggest that LEAP2 deletion does not counteract the effects of ghrelin deletion during insulin-induced hypoglycemia. Presentation: Friday, June 16, 2023

OR18-03 Peripheral But Not Hepatic Insulin Resistance Associates With Adverse Vascular And Metabolic Health In Type 1 Diabetes: A Possible Target For Adjunctive Therapy

Abstract Disclosure: J.R. Snaith: None. N. Olsen: None. G. Kowalski: None. C. Bruce: None. J. Holmes-Walker: None. J.R. Greenfield: None. Insulin resistance in type 1 diabetes (T1D) is a cardiometabolic risk factor that is potentially targetable with adjunctive therapy. Prior studies of metformin in T1D have yielded mixed results. Whether liver and/or muscle insulin resistance is a prerequisite for metformin’s action in adults with T1D is unknown. The INTIMET study recruited 40 adults with T1D (age 37.4±8.8 years, HbA1c 7.5±0.9%, diabetes duration 22.9±8.8 years, BMI 26.4±0.9 kg/m2) and 20 age- and BMI-matched controls without diabetes. Subjects with T1D were randomized to metformin extended-release 1500mg daily or placebo for 26 weeks. Two-step hyperinsulinemic euglycemic clamps (low-dose 20 mU/m2/min, high-dose 60 mU/m2/min insulin) using 6,6-2H2-glucose tracers assessed liver (basal glucose rate of appearance [B-Ra] and low-dose endogenous glucose production [L-EGP]; primary outcomes) and muscle (high-dose glucose infusion rate [GIR]; secondary outcome) insulin resistance at t=0 in all subjects and at t=26 weeks in T1D. Dual-energy x-ray absorptiometry was used to measure fat free mass and visceral adipose tissue (VAT). Applanation tonometry was used to measure arterial stiffness (AIx, augmentation index). Adults with T1D and controls had similar B-Ra (18.2±5.1 vs 18.3±2.2 mmol/kgFFM/min; p=0.87). However, T1D were insulin-resistant at the liver (L-EGP 5.9±2.2 vs 3.6±1.7 mmol/kgFFM/min; p&amp;lt;0.001) and at muscle (GIR 62±20 vs 88±18 µmol/min·kgFFM; p&amp;lt;0.001). Despite these differences, VAT was comparable. In all subjects, baseline GIR correlated with L-EGP (r=-0.343; p=0.008), VAT (r=-0.269; p=0.039) and BMI (r=-0.304; p=0.019). In contrast, baseline L-EGP did not relate to VAT (r=0.060; p=0.653) or BMI (r=0.173; p=0.189). Adults with T1D had borderline higher AIx than controls (11.2±11.4 vs 4.7±13.1%, p=0.05). In the whole group, GIR was associated with LogAIx (r=-0.258, p=0.048), but L-EGP was not (r=0.154; p=0.246). In T1D, HbA1c correlated with GIR (r=-0.329; p=0.041) but L-EGP did not (r=0.307; p=0.057). After 26 weeks, there was no difference between metformin vs placebo-treated T1D subjects in HbA1c and weight, or B-Ra, L-EGP or GIR using generalised linear regression adjusted for age and baseline B-Ra, L-EGP and GIR. In these models, baseline GIR inversely predicted L-EGP (p=0.027) and directly predicted GIR (p&amp;lt;0.001) at 26 weeks. Adults with T1D exhibited greater liver and muscle insulin resistance, and higher arterial stiffness, which was not improved with metformin. Muscle but not liver insulin resistance related to BMI, VAT, HbA1c and AIx. Baseline muscle insulin resistance predicted muscle and hepatic insulin resistance at 26 weeks, irrespective of metformin treatment. This study highlights 1) the importance of muscle but not liver insulin resistance in T1D and 2) the need to identify muscle insulin resistant T1D individuals to enable interventions that improve vascular and metabolic outcomes. Presentation: Saturday, June 17, 2023

THU302 Protective Effects Of Lactation On Maternal Metabolism

Abstract Disclosure: J.R. Hens: None. Y. Ding: None. S. Brown: None. H. Song: None. J.J. Wysolmerski: None. R. Belfort De Aguiar: None. A history of lactation significantly lowers the risk of developing Type 2 diabetes (T2D) by almost 50%. However, little is known about how milk production durably changes maternal metabolism. We hypothesized that lactation protects against diabetes by improving maternal glucose metabolism. Changes in body composition, glucose metabolism, insulin secretion and tissue triglyceride levels were measured in age-matched cohorts of mice that lactated (L) or did not lactate but went through a pregnancy (NL); age-matched virgins served as controls (V). L and NL mice were studied 4 weeks after weaning of pups from the L group. An euglycemic-hyperinsulinemic clamp was used to further examine glucose metabolism. Multiple rounds of lactation were examined to determine if body composition or glucose metabolism changed with repeated cycles of reproduction. Liver weight was higher in L mice when compared to V mice. Liver triglycerides were lower in L and NL mice when compared to V mice. Circulating fasting levels of plasma free fatty acids were unchanged between the three groups. Perigonadal fat trended higher in NL mice compared to L and V mice after one round of lactation. However, after two rounds of lactation, NL mice had significantly more perigonadal fat than L or V mice. Fasting glucose trended lower in L mice compared to NL mice, but there was no difference in insulin levels between groups. The area under the curve of glucose tolerance test was not different between groups. Pancreases from L mice had increased numbers of islets compared to NL and V mice. Insulin action was assessed in chow-fed, conscious, unrestrained L, NL, and V mice using the euglycemic-hyperinsulinemic clamp technique. Tail-vein glucose was clamped at 100-120 mg/dL. The normalized glucose infusion rate to insulin was significantly lower (p=0.01) in NL mice (41.9 +/- 17) compared to V mice (91.8 +/- 14 and L mice (83.8 +/- 27). Our results suggest that pregnancy and lactation significantly alter the metabolic functions of liver, adipose, muscle, and pancreas. Furthermore, a history of lactation improves insulin sensitivity in parous mice. Further study of the metabolic changes occurring during lactation may have wide-ranging implications for women’s health. Presentation: Thursday, June 15, 2023