Vaccine-boosted CAR T crosstalk with host immunity to reject tumors with antigen heterogeneity.

Chimeric antigen receptor (CAR) T cell therapy effectively treats human cancer, but the loss of the antigen recognized by the CAR poses a major obstacle. We found that in vivo vaccine boosting of CAR T cells triggers the engagement of the endogenous immune system to circumvent antigen-negative tumor escape. Vaccine-boosted CAR T promoted dendritic cell (DC) recruitment to tumors, increased tumor antigen uptake by DCs, and elicited the priming of endogenous anti-tumor T cells. This process was accompanied by shifts in CAR T metabolism toward oxidative phosphorylation (OXPHOS) and was critically dependent on CAR-T-derived IFN-γ. Antigen spreading (AS) induced by vaccine-boosted CAR T enabled a proportion of complete responses even when the initial tumor was 50% CAR antigen negative, and heterogeneous tumor control was further enhanced by the genetic amplification of CAR T IFN-γ expression. Thus, CAR-T-cell-derived IFN-γ plays a critical role in promoting AS, and vaccine boosting provides a clinically translatable strategy to drive such responses against solid tumors.

A randomized pharmacokinetic and pharmacodynamic trial of two regular human insulins demonstrates bioequivalence in type 1 diabetes and availability of biosimilar insulin may improve access to this medication.

AIMS: To compare the pharmacokinetic (PK) and pharmacodynamic (PD) effects and safety of therapeutic dosages of a regular insulin (experimental drug) produced by Bioton S.A. (Warsaw, Poland) versus Humulin® R, a regular insulin (reference drug) produced by Eli Lilly (Indianapolis, Indiana). MATERIALS AND METHODS: In a single-centre, randomized, double-blinded phase 1 crossover study, we used the manual euglycaemic clamp technique to compare PK and PD profiles between single subcutaneous doses (0.3 units/kg) of the two regular insulins in participants with type 1 diabetes (T1DM) with a washout period of 14 (± 7) days between tests. RESULTS: We evaluated 56 participants. The mean participant age and body mass index were 32.9 years and 22.9 kg/m2 , respectively. The ratios (experimental/reference) of the geometric means of maximum plasma insulin concentration and for plasma insulin area under the curve (AUC) were 0.909 (90% confidence interval [CI] 0.822-1.01) and 0.993 (90% CI 0.944-1.04), respectively. The ratios of the geometric means of maximum glucose infusion rate (GIR) and for GIR AUC were 0.999 (95% CI 0.912-1.09) and 1.04 (95% CI 0.962-1.12), respectively. CONCLUSIONS: The experimental product regular human insulin and comparator Humulin® R are bioequivalent in patients with T1DM. Wider entry to the pharmaceutical market of affordable, biosimilar regular insulins may substantially improve access to insulin for many socioeconomically disadvantaged patients with diabetes.

A pragmatic low carbohydrate diet intervention changes neither carbohydrate consumption nor glycemia in adolescents and young adults with type 1 diabetes in a randomized trial.

OBJECTIVE: Despite enthusiasm for low carbohydrate diets (LCDs) among patients with type 1 diabetes (T1DM), no prospective study has investigated outcomes in adolescent T1DM. We aimed to quantify a pragmatic LCD intervention's impact on glycemia, lipidemia, and quality of life (QOL) in adolescents with T1DM. RESEARCH DESIGN AND METHODS: At an academic center, we randomized 39 patients with T1DM aged 13-21 years to one of three 12-week interventions: an LCD, an isocaloric standard carbohydrate diet (SCD), or general diabetes education without a prescriptive diet. Glycemic outcomes included glycosylated hemoglobin (HbA1c) and continuous glucose monitoring. RESULTS: There were no significant differences in glycemic, lipidemic, or QOL parameters between groups at any timepoint. Median HbA1c was similar at baseline between groups and did not change appreciably (7.9%-8.4% in LCDs, 7.9%-7.9% in SCDs, and 8.2%-7.8% in controls). Change in carbohydrate consumption was minimal with only one participant reaching target carbohydrate intake. CONCLUSIONS: This pragmatic LCD intervention did not alter carbohydrate consumption or glycemia. Although this study was unable to evaluate a highly controlled LCD, it indicates that adolescents are unlikely to implement an educational LCD intervention in routine clinic settings. Thus, this approach is unlikely to effectively mitigate hyperglycemia in adolescents.

Importance of the route of insulin delivery to its control of glucose metabolism.

Pancreatic insulin secretion produces an insulin gradient at the liver compared with the rest of the body (approximately 3:1). This physiological distribution is lost when insulin is injected subcutaneously, causing impaired regulation of hepatic glucose production and whole body glucose uptake, as well as arterial hyperinsulinemia. Thus, the hepatoportal insulin gradient is essential to the normal control of glucose metabolism during both fasting and feeding. Insulin can regulate hepatic glucose production and uptake through multiple mechanisms, but its direct effects on the liver are dominant under physiological conditions. Given the complications associated with iatrogenic hyperinsulinemia in patients treated with insulin, insulin designed to preferentially target the liver may have therapeutic advantages.

Roux-en-Y gastric bypass surgery improves hepatic glucose metabolism and reduces plasma kisspeptin levels in morbidly obese patients with type 2 diabetes.

Roux-en-Y gastric bypass surgery (RYGB) is known to improve whole-body glucose metabolism in patients with type 2 diabetes (T2D), although the mechanisms are not entirely clear and are likely multifactorial. The aim of this study was to assess fasting hepatic glucose metabolism and other markers of metabolic activity before and after RYGB in patients with and without T2D. Methods: Metabolic characteristics of patients who are obese with T2D were compared with those without the disease (non-T2D) before and 1 and 6 mo after RYGB. Fasting plasma insulin and the insulin:glucagon ratio were markedly reduced as early as 1 mo after RYGB in both patients with T2D and without T2D. Despite this reduction, endogenous glucose production and fasting plasma glucose levels were lower in both groups after RYGB, with the reductions being much larger in T2D. Plasma kisspeptin, an inhibitor of insulin secretion, was reduced only in T2D after surgery. Improved hepatic glucose metabolism and lower plasma kisspeptin in T2D after RYGB may link improved hepatic function with enhanced insulin responsiveness after surgery.NEW & NOTEWORTHY Our manuscript is the first, to the best of our knowledge, to present data showing that Roux-en-Y gastric bypass surgery (RYGB) lowers fasting kisspeptin levels in patients who are obese with type 2 diabetes. This lowering of kisspeptin is important because it could link improvements in liver glucose metabolism after RYGB with increased insulin responsiveness also seen after surgery.

Increased proportion of time in hybrid closed-loop "Auto Mode" is associated with improved glycaemic control for adolescent and young patients with adult type 1 diabetes using the MiniMed 670G insulin pump.

The Medtronic MiniMed 670G system delivers insulin to patients with type 1 diabetes mellitus (T1DM) using either its hybrid closed-loop (HCL) "Auto Mode" feature or an open-loop mode. In this retrospective, cross-sectional analysis, we quantified the association between time in Auto Mode and both haemoglobin A1c (HbA1c) and time in range (TIR, sensor glucose 70-180 mg/dL) among 96 paediatric and young adult patients with T1DM. The median percentage time in Auto Mode was 38.5% (interquartile range 0%-64%). The percentage time in Auto Mode significantly correlated with HbA1c after adjustment for covariables (ß = -0.008, P = 0.014). Each daily 3.4-h increase in Auto Mode time was associated with a 0.1% decrease in HbA1c. Auto Mode time was also correlated with TIR after adjustment for covariables (ß = 0.14, P = 0.02): for each daily 8.6-h increase in Auto Mode time, TIR increased by 5%. While Auto Mode use was low, increased time in Auto Mode was associated with a significantly lower HbA1c and increased TIR. These findings emphasize the importance of identifying strategies to improve the ease of use of HCL systems.

Medical and Psychological Considerations for Carbohydrate-Restricted Diets in Youth With Type 1 Diabetes.

PURPOSE OF REVIEW: Given the challenges achieving recommended glycemic targets in youth with type 1 diabetes (T1D), providers may consider recommending carbohydrate-restricted diets (CRDs) to optimize glycemic control. The goal of the present review is to describe relevant literature on the potential medical and psychosocial benefits and risks of CRDs in youth with T1D. RECENT FINDINGS: Limited data exist on the effects of CRDs in pediatric populations. Findings from studies with youth and adults are mixed; some indicate that CRDs may be associated with desirable medical outcomes, such as improved glycemic control and reduced HbA1c, which may contribute to positive psychological outcomes such as reduced diabetes distress and depressive symptoms. Others suggest that CRDs may also be associated with detrimental outcomes, including mineral deficiencies and suboptimal growth, and dietary restriction has been linked to greater diabetes distress, disordered eating, and diabetes management. More research is needed to evaluate benefits and risks of CRDs in youth. Providers should exercise caution when discussing CRDs with youth and families, particularly when considering CRDs for youth at elevated risk for eating disordered behavior.

Enterically delivered insulin tregopil exhibits rapid absorption characteristics and a pharmacodynamic effect similar to human insulin in conscious dogs.

AIMS: Current therapy fails to emulate rapid (first-phase) insulin release in relation to a meal, a key defect in types 1 and 2 diabetes. We aimed to quantify the pharmacokinetic (PK) and pharmacodynamic (PD) profile of insulin tregopil, an enterically-absorbed insulin analog that restores the normal distribution of insulin between the hepatic portal and peripheral circulations. MATERIALS AND METHODS: The PK and PD profiles of insulin tregopil were studied in overnight-fasted, catheterized, conscious canines using four approaches: (1) equimolar intraportal infusions of tregopil vs human insulin; (2) escalating doses of oral tregopil; (3) identical, consecutive enteric doses of tregopil; and (4) comparison of oral tregopil to inhaled and subcutaneous human insulin administration. RESULTS: Equimolar intraportal infusions of tregopil and human insulin resulted in very similar PK profiles and PD profiles were nearly identical. Enteric delivery of tregopil brought about rapid absorption with tmax = 20 minutes in most cases. Median tmax was 20 minutes for oral tregopil and inhaled insulin and 88 minutes for subcutaneous human insulin. The time required for arterial plasma insulin levels to return to baseline was approximately 90, 210 and 360 minutes for oral tregopil, inhaled insulin and subcutaneous insulin, respectively. CONCLUSIONS: Enterically delivered tregopil is rapidly absorbed and restores a portal-to-peripheral vascular distribution. These characteristics should improve postprandial hyperglycaemia in types 1 and 2 diabetes.

Peripherally delivered hepatopreferential insulin analog insulin-406 mimics the hypoglycaemia-sparing effect of portal vein human insulin infusion in dogs.

AIMS: We previously quantified the hypoglycaemia-sparing effect of portal vs peripheral human insulin delivery. The current investigation aimed to determine whether a bioequivalent peripheral vein infusion of a hepatopreferential insulin analog, insulin-406, could similarly protect against hypoglycaemia. MATERIALS AND METHODS: Dogs received human insulin infusions into either the hepatic portal vein (PoHI, n = 7) or a peripheral vein (PeHI, n = 7) for 180 minutes at four-fold the basal secretion rate (6.6 pmol/kg/min) in a previous study. Insulin-406 (Pe406, n = 7) was peripherally infused at 6.0 pmol/kg/min, a rate determined to decrease plasma glucose by the same amount as with PoHI infusion during the first 60 minutes. Glucagon was fixed at basal concentrations, mimicking the diminished α-cell response seen in type 1 diabetes. RESULTS: Glucose dropped quickly with PeHI infusion, reaching 41 ± 3 mg/dL at 60 minutes, but more slowly with PoHI and Pe406 infusion (67 ± 2 and 72 ± 4 mg/dL, respectively; P < 0.01 vs PeHI for both). The hypoglycaemic nadir (c. 40 mg/dL) occurred at 60 minutes with PeHI infusion vs 120 minutes with PoHI and Pe406 infusion. ΔAUCepinephrine during the 180-minute insulin infusion period was two-fold higher with PeHI infusion compared with PoHI and Pe406 infusion. Glucose production (mg/kg/min) was least suppressed with PeHI infusion (Δ = 0.79 ± 0.33) and equally suppressed with PoHI and Pe406 infusion (Δ = 1.16 ± 0.21 and 1.18 ± 0.17, respectively; P = NS). Peak glucose utilization (mg/kg/min) was highest with PeHI infusion (4.94 ± 0.17) and less with PoHI and Pe406 infusion (3.58 ± 0.58 and 3.26 ± 0.08, respectively; P < 0.05 vs Pe for both). CONCLUSIONS: Peripheral infusion of hepatopreferential insulin can achieve a metabolic profile that closely mimics portal insulin delivery, which reduces the risk of hypoglycaemia compared with peripheral insulin infusion.

A New Animal Model of Insulin-Glucose Dynamics in the Intraperitoneal Space Enhances Closed-Loop Control Performance.

Current artificial pancreas systems (AP) operate via subcutaneous (SC) glucose sensing and SC insulin delivery. Due to slow diffusion and transport dynamics across the interstitial space, even the most sophisticated control algorithms in on-body AP systems cannot react fast enough to maintain tight glycemic control under the effect of exogenous glucose disturbances caused by ingesting meals or performing physical activity. Recent efforts made towards the development of an implantable AP have explored the utility of insulin infusion in the intraperitoneal (IP) space: a region within the abdominal cavity where the insulin-glucose kinetics are observed to be much more rapid than the SC space. In this paper, a series of canine experiments are used to determine the dynamic association between IP insulin boluses and plasma glucose levels. Data from these experiments are employed to construct a new mathematical model and to formulate a closed-loop control strategy to be deployed on an implantable AP. The potential of the proposed controller is demonstrated via in-silico experiments on an FDA-accepted benchmark cohort: the proposed design significantly outperforms a previous controller designed using artificial data (time in clinically acceptable glucose range: 97.3±1.5% vs. 90.1±5.6%). Furthermore, the robustness of the proposed closed-loop system to delays and noise in the measurement signal (for example, when glucose is sensed subcutaneously) and deleterious glycemic changes (such as sudden glucose decline due to physical activity) is investigated. The proposed model based on experimental canine data leads to the generation of more effective control algorithms and is a promising step towards fully automated and implantable artificial pancreas systems.

Glucose autoregulation is the dominant component of the hormone-independent counterregulatory response to hypoglycemia in the conscious dog.

The contribution of hormone-independent counterregulatory signals in defense of insulin-induced hypoglycemia was determined in adrenalectomized, overnight-fasted conscious dogs receiving hepatic portal vein insulin infusions at a rate 20-fold basal. Either euglycemia was maintained (group 1) or hypoglycemia (≈45 mg/dl) was allowed to occur. There were three hypoglycemic groups: one in which hepatic autoregulation against hypoglycemia occurred in the absence of sympathetic nervous system input (group 2), one in which autoregulation occurred in the presence of norepinephrine (NE) signaling to fat and muscle (group 3), and one in which autoregulation occurred in the presence of NE signaling to fat, muscle, and liver (group 4). Average net hepatic glucose balance (NHGB) during the last hour for groups 1-4 was -0.7 ± 0.1, 0.3 ± 0.1 (P < 0.01 vs. group 1), 0.7 ± 0.1 (P = 0.01 vs. group 2), and 0.8 ± 0.1 (P = 0.7 vs. group 3) mg·kg-1·min-1, respectively. Hypoglycemia per se (group 2) increased NHGB by causing an inhibition of net hepatic glycogen synthesis. NE signaling to fat and muscle (group 3) increased NHGB further by mobilizing gluconeogenic precursors resulting in a rise in gluconeogenesis. Lowering glucose per se decreased nonhepatic glucose uptake by 8.9 mg·kg-1·min-1, and the addition of increased neural efferent signaling to muscle and fat blocked glucose uptake further by 3.2 mg·kg-1·min-1 The addition of increased neural efferent input to liver did not affect NHGB or nonhepatic glucose uptake significantly. In conclusion, even in the absence of increases in counterregulatory hormones, the body can defend itself against hypoglycemia using glucose autoregulation and increased neural efferent signaling, both of which stimulate hepatic glucose production and limit glucose utilization.

Combination SGLT2 Inhibitor and Glucagon Receptor Antagonist Therapy in Type 1 Diabetes: A Randomized Clinical Trial.

OBJECTIVE: To examine the effects of insulin-adjunctive therapy with a sodium-glucose cotransporter 2 (SGLT2) inhibitor and a glucagon receptor antagonist (GRA) on glycemia, insulin use, and ketogenesis during insulinopenia in type 1 diabetes. RESEARCH DESIGN AND METHODS: In a randomized, double-blind, placebo-controlled, crossover trial we assessed the effects of adjunctive SGLT2 inhibitor therapy (dapagliflozin 10 mg daily) alone and in combination with the GRA volagidemab (70 mg weekly) in 12 adults with type 1 diabetes. Continuous glucose monitoring, insulin dosing, and insulin withdrawal tests (IWT) for measurement of glucose and ketogenesis during insulinopenia were completed during insulin-only (Baseline), SGLT2 inhibitor, and combination (SGLT2 inhibitor + GRA) therapy periods. RESULTS: Average glucose and percent time with glucose in range (70-180 mg/dL) improved with combination therapy versus Baseline and SGLT2 inhibitor (131 vs. 150 and 138 mg/dL [P < 0.001 and P = 0.01] and 86% vs. 70% and 78% [P < 0.001 and P = 0.03], respectively) without increased hypoglycemia. Total daily insulin use decreased with combination therapy versus Baseline and SGLT2 inhibitor (0.41 vs. 0.56 and 0.52 units/kg/day [P < 0.001 and P = 0.002]). Peak ß-hydroxybutyrate levels during IWT were lower with combination therapy than with SGLT2 inhibitor (2.0 vs. 2.4 mmol/L; P = 0.048) and similar to levels reached during the Baseline testing period (2.1 mmol/L). Participants reported enhanced treatment acceptability and satisfaction with combination therapy. CONCLUSIONS: Glucagon antagonism enhances the therapeutic effects of SGLT2 inhibition in type 1 diabetes. Combination therapy improves glycemic control, reduces insulin dosing, and suggests a strategy to unlock the benefits of SGLT2 inhibitors while mitigating the risk of diabetic ketoacidosis.

Reliability of Handheld Blood Glucose Monitors in Neonates: Trustworthy Arterial Readings but Capillary Results Warrant Caution for Hypoglycemia.

BACKGROUND: Accurate glucose monitoring is vitally important in neonatal intensive care units (NICUs) and clinicians use blood glucose monitors (BGM), such as the Inform II, for bedside glucose monitoring. Studies on BGM use in neonates have demonstrated good reliability; however, most studies only included healthy-term neonates. Therefore, the applicability of results to the preterm and/or ill neonate is limited. OBJECTIVES: In preterm and ill neonates, quantify differences in glucose concentrations between (1) capillary glucose (measured by BGM) and arterial glucose (measured by YSI 2300 Stat Plus) and (2) between aliquots from the same arterial blood sample, one measured by BGM versus one by YSI. DESIGN/METHODS: Forty neonates were included in the study. Using Inform II, we measured glucose concentrations on blood samples simultaneously collected from capillary circulation via heel puncture and from arterial circulation via an umbilical catheter. Plasma was then separated from the remainder of the arterial whole blood sample and a YSI 2300 Stat Plus measured plasma glucose concentration. RESULTS: The dominant majority of arterial BGM results met the Clinical and Laboratory Standard Institute (CLSI) and Food and Drug Administration (FDA) tolerance criteria. Greater discrepancy was observed with capillary BGM values with an average of 27.5% of results falling outside tolerance criteria. CONCLUSIONS: Blood glucose monitor testing provided reliable results from arterial blood. However, users should interpret hypoglycemic results obtained from capillary blood with caution.

A Large Thyroid Goiter in a Newborn With Congenital Hypothyroidism: Timeline for Decrease in Size of Thyroid.

Congenital hypothyroidism rarely causes a clinically significant neck mass in newborns. We present the case of a newborn with congenital hypothyroidism and significantly enlarged goiter and discuss imaging considerations and medical and surgical management. This infant was prenatally discovered to have a midline neck mass on 28 week ultrasound measuring 6.0 cm × 3.4 cm × 5.8 cm. Diagnostic cordocentesis demonstrated elevated thyroid-stimulating hormone (TSH, 361 µIU/mL). Maternal evaluation for thyroid disease and antithyroid antibodies was negative. A Cesarean section at 38 weeks gestation was recommended due to hyperextension of the fetal neck. The infant was intubated for respiratory distress. Postnatal magnetic resonance imaging revealed a 5.5 cm × 4.4 cm × 7.6 cm goiter and laboratory studies confirmed the diagnosis of primary hypothyroidism (TSH 16.7 µIU/mL). Treatment was initiated with intravenous levothyroxine and transitioned to oral supplementation. Serial ultrasounds showed decreased goiter volume over several weeks, with recent volume per lobe being 22% and 44% of original volume. This case demonstrates the importance of prompt diagnosis and initiation of thyroid hormone replacement, allowing for significant goiter regression without surgical intervention and ensuring normal growth and neurodevelopmental outcome. Surgical management should be considered for those with persistent compressive symptoms despite optimal medical management.

A high-fat and fructose diet in dogs mirrors insulin resistance and ß-cell dysfunction characteristic of impaired glucose tolerance in humans.

This study examined the impact of a hypercaloric high-fat high-fructose diet (HFFD) in dogs as a potential model for human impaired glucose tolerance (IGT) and type 2 diabetes mellitus (T2DM). The HFFD not only led to weight gain but also triggered metabolic alterations akin to the precursors of human T2DM, notably insulin resistance and ß-cell dysfunction. Following the HFFD intervention, the dogs exhibited a 50% decrease in insulin sensitivity within the first four weeks, paralleling observations in the progression from normal to IGT in humans. Calculations of the insulinogenic index using both insulin and C-peptide measurements during oral glucose tolerance tests revealed a significant and sustained decrease in early-phase insulin release, with partial compensation in the later phase, predominantly stemming from reduced hepatic insulin clearance. In addition, the Disposition Index, representing the ß-cell's capacity to compensate for diminished insulin sensitivity, fell dramatically. These results confirm that a HFFD can instigate metabolic changes in dogs akin to the early stages of progression to T2DM in humans. The study underscores the potential of using dogs subjected to a HFFD as a model organism for studying human IGT and T2DM.

Low protease activity in B cell follicles promotes retention of intact antigens after immunization.

The structural integrity of vaccine antigens is critical to the generation of protective antibody responses, but the impact of protease activity on vaccination in vivo is poorly understood. We characterized protease activity in lymph nodes and found that antigens were rapidly degraded in the subcapsular sinus, paracortex, and interfollicular regions, whereas low protease activity and antigen degradation rates were detected in the vicinity of follicular dendritic cells (FDCs). Correlated with these findings, immunization regimens designed to target antigen to FDCs led to germinal centers dominantly targeting intact antigen, whereas traditional immunizations led to much weaker responses that equally targeted the intact immunogen and antigen breakdown products. Thus, spatially compartmentalized antigen proteolysis affects humoral immunity and can be exploited.

SGLT2 Inhibition Increases Fasting Glucagon but Does Not Restore the Counterregulatory Hormone Response to Hypoglycemia in Participants With Type 1 Diabetes.

Individuals with type 1 diabetes have an impaired glucagon counterregulatory response to hypoglycemia. Sodium-glucose cotransporter (SGLT) inhibitors increase glucagon concentrations. We evaluated whether SGLT inhibition restores the glucagon counterregulatory hormone response to hypoglycemia. Adults with type 1 diabetes (n = 22) were treated with the SGLT2 inhibitor dapagliflozin (5 mg daily) or placebo for 4 weeks in a randomized, double-blind, crossover study. After each treatment phase, participants underwent a hyperinsulinemic-hypoglycemic clamp. Basal glucagon concentrations were 32% higher following dapagliflozin versus placebo, with a median within-participant difference of 2.75 pg/mL (95% CI 1.38-12.6). However, increased basal glucagon levels did not correlate with decreased rates of hypoglycemia and thus do not appear to be protective in avoiding hypoglycemia. During hypoglycemic clamp, SGLT2 inhibition did not change counterregulatory hormone concentrations, time to recovery from hypoglycemia, hypoglycemia symptoms, or cognitive function. Thus, despite raising basal glucagon concentrations, SGLT inhibitor treatment did not restore the impaired glucagon response to hypoglycemia. We propose that clinical reduction in hypoglycemia associated with these agents is a result of changes in diabetes care (e.g., lower insulin doses or improved glycemic variability) as opposed to a direct, physiologic effect of these medications on α-cell function.

COVID-19 Exacerbates Insulin Resistance During Diabetic Ketoacidosis in Pediatric Patients With Type 1 Diabetes.

OBJECTIVE: Although mortality from coronavirus disease 2019 (COVID-19) among youth with type 1 diabetes is rare, severe acute respiratory syndrome coronavirus 2 is associated with increased pediatric hospitalizations for diabetic ketoacidosis (DKA). To clarify whether the relationship between COVID-19 and DKA is coincidental or causal, we compared tissue glucose disposal (TGD) during standardized treatment for DKA between pediatric patients with COVID-19 and those without COVID-19. RESEARCH DESIGN AND METHODS: We retrospectively compared TGD during standardized therapy for DKA in all children with preexisting type 1 diabetes with or without COVID-19. Cases were assessed beginning with the first case of COVID-19-positive DKA on 19 June 2020 through 2 February 2022. RESULTS: We identified 93 COVID-19-negative patients and 15 COVID-19-positive patients who were treated for DKA, with similar baseline characteristics between groups. Median TGD was 46% lower among patients who had COVID-19 compared with those who did not (P = 0.013). CONCLUSIONS: These results suggest that COVID-19 provokes a metabolic derangement over and above factors that typically contribute to pediatric DKA. These findings underscore the significant and direct threat posed by COVID-19 in pediatric type 1 diabetes and emphasize the importance of mitigation and monitoring including through vaccination as a primary prevention.

Insulin Infusion Is Linked to Increased NPPC Expression in Muscle and Plasma C-type Natriuretic Peptide in Male Dogs.

The purpose of this study was to assess insulin-stimulated gene expression in canine skeletal muscle with a particular focus on NPPC, the gene that encodes C-type natriuretic peptide, a key hormonal regulator of cardiometabolic function. Four conscious canines underwent hyperinsulinemic, euglycemic clamp studies. Skeletal muscle biopsy and arterial plasma samples were collected under basal and insulin-stimulated conditions. Bulk RNA sequencing of muscle tissue was performed to identify differentially expressed genes between these 2 steady-state conditions. Our results showed that NPPC was the most highly expressed gene in skeletal muscle in response to insulin infusion, rising 4-fold between basal and insulin-stimulated conditions. In support of our RNA sequencing data, we found that raising the plasma insulin concentration 15-fold above basal elicited a 2-fold (P = 0.0001) increase in arterial plasma concentrations of N-terminal prohormone C-type natriuretic peptide. Our data suggest that insulin may play a role in stimulating secretion of C-type natriuretic peptide by skeletal muscle. In this context, C-type natriuretic peptide may act in a paracrine manner to facilitate muscle-vascular bed crosstalk and potentiate insulin-mediated vasodilation. This could serve to enhance insulin and glucose delivery, particularly in the postprandial absorptive state.