Hypoglycaemia induces an acute and sustained inflammatory response both in people with type 1 diabetes and in people without diabetes. To investigate the role of adrenaline (epinephrine) in this response, we measured the inflammatory effects of adrenaline in a concentration and timeframe comparable to that seen during hypoglycaemia, in people with type 1 diabetes and matched control participants without diabetes. Adults with type 1 diabetes and matched control participants received adrenaline intravenously at 0.04 µg kg−1 min−1 for 1 h. Blood was drawn at baseline, after 30, 60 and 180 min, and on days 1, 3 and 7 following start of adrenaline administration, to determine white blood cell counts, cytokine secretion using ex vivo stimulation of isolated monocytes and circulating inflammatory markers using the Olink inflammatory panel. Adrenaline acutely increased neutrophil, lymphocyte and monocyte counts in both groups. While neutrophil and monocyte levels returned to baseline after 1 day, lymphocytes remained elevated for 7 days. Adrenaline acutely altered monocyte function towards a more inflammatory phenotype, reflected by increased secretion of cytokines after ex vivo stimulation with lipopolysaccharide in both groups. Adrenaline also increased circulating inflammatory proteins, including urokinase-type plasminogen activator, Fms-like tyrosine kinase 3 ligand, chemokine (C-X3-C motif) ligand 1 and fibroblast growth factor 21, after 7 days in both groups, with a more pronounced response in people with type 1 diabetes. Levels of adrenaline similar to those seen in response to hypoglycaemia elicit an acute and prolonged inflammatory response in people with type 1 diabetes and matched control participants on a cellular, functional and protein level. These findings suggest that adrenaline is a prominent driver of inflammatory responses following hypoglycaemia. ClinicalTrials.gov NCT05990933

In people with type 2 diabetes and obesity, Roux-en-Y gastric bypass (RYGB) can induce remission of diabetes. While RYGB has been reported to improve beta cell function in individuals with type 2 diabetes, it is unclear whether this is accompanied by changes in beta cell mass. In this explorative proof-of-concept study, we compared beta cell mass, measured by [68Ga]Ga-NODAGA-exendin-4 positron emission tomography/computed tomography (PET/CT) imaging, between individuals achieving remission of type 2 diabetes following RYGB and those not achieving remission. Individuals with (n=8) and without (n=9) remission of type 2 diabetes up to 4 years after RYGB were injected with 100 ± 5.6 MBq of [68Ga]Ga-NODAGA-exendin-4 to quantify beta cell mass using PET/CT imaging. Beta cell function was determined by the AUC for C-peptide and the ratio between the AUC for C-peptide and AUC for glucose obtained from a combined arginine stimulation test (ARGT) and OGTT. Acquired variables are expressed as mean ± SD or median (IQR) based on normality. Individuals with remission of type 2 diabetes had a shorter diabetes duration than those without remission. After RYGB, beta cell function was higher in individuals with remission of type 2 diabetes than individuals without remission, based on both ARGTs (AUCC-peptide/fasting glucose 1.1 ± 0.41 vs 0.32 ± 0.16 nmol × min/mmol, p=0.001) and OGTTs (AUCC-peptide:AUCglucose 0.15 [0.11–0.24] vs 0.032 [0.023–0.054], p=0.005). In contrast, beta cell mass did not differ between individuals with or without remission of type 2 diabetes (3.6 [3.4–5.4] vs 3.8 [1.9–4.5] kBq/MBq, p=0.87) and did not correlate with beta cell function or body weight parameters. HOMA2-

Importance:Metformin and glyburide monotherapy are used as alternatives to insulin in managing gestational diabetes. Whether a sequential strategy of these oral agents results in noninferior perinatal outcomes compared with insulin alone is unknown. Objective:To test whether a treatment strategy of oral glucose-lowering agents is noninferior to insulin for prevention of large-for-gestational-age infants. Design, Setting, and Participants:Randomized, open-label noninferiority trial conducted at 25 Dutch centers from June 2016 to November 2022 with follow-up completed in May 2023. The study enrolled 820 individuals with gestational diabetes and singleton pregnancies between 16 and 34 weeks of gestation who had insufficient glycemic control after 2 weeks of dietary changes (defined as fasting glucose >95 mg/dL [>5.3 mmol/L], 1-hour postprandial glucose >140 mg/dL [>7.8 mmol/L], or 2-hour postprandial glucose >120 mg/dL [>6.7 mmol/L], measured by capillary glucose self-testing). Interventions:Participants were randomly assigned to receive metformin (initiated at a dose of 500 mg once daily and increased every 3 days to 1000 mg twice daily or highest level tolerated; n = 409) or insulin (prescribed according to local practice; n = 411). Glyburide was added to metformin, and then insulin substituted for glyburide, if needed, to achieve glucose targets. Main Outcomes and Measures:The primary outcome was the between-group difference in the percentage of infants born large for gestational age (birth weight >90th percentile based on gestational age and sex). Secondary outcomes included maternal hypoglycemia, cesarean delivery, pregnancy-induced hypertension, preeclampsia, maternal weight gain, preterm delivery, birth injury, neonatal hypoglycemia, neonatal hyperbilirubinemia, and neonatal intensive care unit admission. Results:Among 820 participants, the mean age was 33.2 (SD, 4.7) years). In participants randomized to oral agents, 79% (n = 320) maintained glycemic control without insulin. With oral agents, 23.9% of infants (n = 97) were large for gestational age vs 19.9% (n = 79) with insulin (absolute risk difference, 4.0%; 95% CI, -1.7% to 9.8%; P = .09 for noninferiority), with the confidence interval of the risk difference exceeding the absolute noninferiority margin of 8%. Maternal hypoglycemia was reported in 20.9% with oral glucose-lowering agents and 10.9% with insulin (absolute risk difference, 10.0%; 95% CI, 3.7%-21.2%). All other secondary outcomes did not differ between groups. Conclusions and Relevance:Treatment of gestational diabetes with metformin and additional glyburide, if needed, did not meet criteria for noninferiority compared with insulin with respect to the proportion of infants born large for gestational age. Trial Registration:Netherlands Trial Registry Identifier: NTR6134.

IMPORTANCE Metformin and glyburide monotherapy are used as alternatives to insulin in managing gestational diabetes. Whether a sequential strategy of these oral agents results in noninferior perinatal outcomes compared with insulin alone is unknown. OBJECTIVE To test whether a treatment strategy of oral glucose-lowering agents is noninferior to insulin for prevention of large-for-gestational-age infants. DESIGN, SETTING, AND PARTICIPANTS Randomized, open-label noninferiority trial conducted at 25 Dutch centers from June 2016 to November 2022 with follow-up completed in May 2023. The study enrolled 820 individuals with gestational diabetes and singleton pregnancies between 16 and 34 weeks of gestation who had insufficient glycemic control after 2 weeks of dietary changes (defined as fasting glucose >95 mg/dL [>5.3 mmol/L], 1-hour postprandial glucose >140 mg/dL [>7.8 mmol/L], or 2-hour postprandial glucose >120 mg/dL [>6.7 mmol/L], measured by capillary glucose self-testing). INTERVENTIONS Participants were randomly assigned to receive metformin (initiated at a dose of 500 mg once daily and increased every 3 days to 1000 mg twice daily or highest level tolerated; n = 409) or insulin (prescribed according to local practice; n = 411). Glyburide was added to metformin, and then insulin substituted for glyburide, if needed, to achieve glucose targets. MAIN OUTCOMES AND MEASURES The primary outcome was the between-group difference in the percentage of infants born large for gestational age (birth weight >90th percentile based on gestational age and sex). Secondary outcomes included maternal hypoglycemia, cesarean delivery, pregnancy-induced hypertension, preeclampsia, maternal weight gain, preterm delivery, birth injury, neonatal hypoglycemia, neonatal hyperbilirubinemia, and neonatal intensive care unit admission. RESULTS Among 820 participants, the mean age was 33.2 (SD, 4.7) years). In participants randomized to oral agents, 79% (n = 320) maintained glycemic control without insulin. With oral agents, 23.9% of infants (n = 97) were large for gestational age vs 19.9% (n = 79) with insulin (absolute risk difference, 4.0%; 95% CI, -1.7% to 9.8%; P = .09 for noninferiority), with the confidence interval of the risk difference exceeding the absolute noninferiority margin of 8%. Maternal hypoglycemia was reported in 20.9% with oral glucose-lowering agents and 10.9% with insulin (absolute risk difference, 10.0%; 95% CI, 3.7%-21.2%). All other secondary outcomes did not differ between groups. CONCLUSIONS AND RELEVANCE Treatment of gestational diabetes with metformin and additional glyburide, if needed, did not meet criteria for noninferiority compared with insulin with respect to the proportion of infants born large for gestational age.

Postbariatric hypoglycemia (PBH) is a serious complication of Roux-en-Y gastric bypass (RYGB), characterized by severe hypoglycemia that may lead to loss of consciousness and seizures. The exact mechanism of PBH is poorly understood. One potential mechanism is β-cell expansion. To this end, we investigated β-cell mass in individuals with and without PBH after RYGB using [68Ga]Ga-NODAGA-exendin-4 positron emission tomography/computed tomography imaging (PET/CT). Individuals with PBH (n = 10) and without PBH (n = 9) after RYGB were included. PET/CT imaging was performed after infusion with 102.2 ± 6.9 MBq of the [68Ga]Ga-NODAGA-exendin-4 tracer to quantify pancreatic β-cell mass. The two groups did not differ with respect to sex, age, BMI, and total body weight loss after RYGB. Time between RYGB and inclusion was longer for individuals with PBH compared with those without. β-Cell mass did not differ between the groups. Individuals with PBH had a smaller pancreas than those without. β-Cell mass correlated neither with body weight parameters nor with metabolic parameters. Our data indicating that β-cell mass does not differ between individuals with and without PBH after RYGB argue against expansion of β-cell mass to explain PBH. ARTICLE HIGHLIGHTS:The exact mechanism of postbariatric hypoglycemia (PBH) is unclear, but β-cell mass expansion is hypothesized to play a role. We used [68Ga]Ga-NODAGA-exendin-4 positron emission tomography/computed tomography (PET/CT) to determine β-cell mass in individuals with and without PBH after Roux-en-Y gastric bypass surgery. β-Cell mass did not differ between individuals with and without PBH. Pancreas volume was lower in individuals with PBH compared with those without PBH. Our data argue against β-cell mass expansion to explain PBH after Roux-en-Y gastric bypass. Further study is required to understand PBH.

Post-bariatric hypoglycemia (PBH) is a serious complication of Roux-en-Y gastric bypass (RYGB), characterized by severe hypoglycemia that may lead to loss of consciousness and seizures. The exact mechanism of PBH is poorly understood. One potential mechanism is beta cell expansion. To this end, we investigated beta cell mass in individuals with and without PBH after RYGB using [68Ga]Ga-NODAGA-exendin-4 PET/CT imaging. Individuals with PBH (n=10) and without PBH (n=9) after RYGB were included. PET/CT imaging was performed after infusion with 102.2±6.9 MBq of the [68Ga]Ga-NODAGA-exendin-4 tracer to quantify pancreatic beta cell mass. The two groups did not differ with respect to sex, age, BMI and total body weight loss after RYGB. Time between RYGB and inclusion was longer for individuals with PBH compared to those without. Beta cell mass did not differ between the groups. Individuals with PBH had a smaller pancreas than those without. Beta cell mass correlated neither with body weight parameters nor with metabolic parameters. Our data indicating that beta cell mass does not differ between individuals with and without PBH after RYGB argue against expansion of beta cell mass to explain PBH.

This study investigated the safety and feasibility of daily ingestion of autologous lyophilized fecal microbiota capsules (a-LFMCs) for preserving beta-cell function in individuals with type 1 diabetes (T1D). We evaluated a-LFMC in an open-label, single-arm pilot study (NCT05323162) with 10 individuals with T1D. The study included a 3-month run-in period, 3 months of daily a-LFMC treatment, and a 3-month follow-up. Beta-cell function was assessed using mixed-meal stimulated C-peptide area under the curve (AUC). During the run-in period, beta-cell function significantly declined (mean ΔAUC -12.02 ± 5.09 nmol/L*min, p = 0.025). There was no decrease in beta-cell function during the a-LFMC treatment period (mean ΔAUC 0.76 ± 5.09 nmol/L*min, p = 0.88) and the follow-up period (mean ΔAUC 0.96 ± 5.09 nmol/L*min, p = 0.85). No serious adverse events occurred, though constipation increased during the treatment period (0% vs. 30%, p = 0.021). a-LFMC treatment was found to be safe and potentially contributes to preserving beta-cell function in T1D patients. A larger randomized placebo-controlled trial is needed to confirm these promising findings.

Glucagon-like peptide 1 receptor (GLP-1R) agonists fail to reduce weight and improve glucose control in a sizable minority of people with type 2 diabetes. We hypothesized that stimulation of the hypothalamic-pituitary-adrenal (HPA) axis by GLP-1R agonists, thus inducing cortisol secretion, could explain this unresponsiveness to GLP-1R agonists. To assess the effects of GLP-1R agonist treatment on the HPA axis, we selected ten individuals with type 2 diabetes with (5 women/5 men) and nine without (4 women/5 men) an adequate response to GLP-1R agonists and used [68Ga]Ga-NODAGA-exendin-4 positron emission tomography (PET)/computed tomography (CT) to quantify GLP-1R expression in the pituitary. Oral glucose tolerance and 24 h urinary cortisol excretion was measured in all participants. Pituitary tracer uptake was observed in all participants with no significant difference between responders and non-responders. Pituitary tracer uptake correlated with the area under the curve for ACTH, urinary cortisol to creatinine ratio and age. Interestingly, men had higher pituitary tracer uptake than women. In conclusion, this study does not indicate a role for pituitary GLP-1R expression and HPA axis stimulation to explain the difference in treatment response to GLP-1R agonists among individuals with type 2 diabetes. The findings of substantial pituitary GLP-1R expression and the significant sex differences require further research.

CONTEXT:Type 1 diabetes (T1D) is associated with alterations of the immune response which persist even after the autoimmunity aspect is resolved. Clinical factors that cause dysregulation, however, are not fully understood.OBJECTIVE:To identify clinical factors that affect immune dysregulation in people with longstanding T1D.DESIGN:In this cross-sectional study, 243 participants with longstanding T1D were recruited between February 2016 and June 2017 at the Radboudumc, the Netherlands. Blood was drawn to determine immune cell phenotype and functionality, as well as circulating inflammatory proteome. Multivariate linear regression was used to determine the association between glycated hemoglobin (HbA1c) levels, duration of diabetes, insulin need, and diabetes complications with inflammation.RESULTS:HbA1c level is positively associated with circulating inflammatory markers (P < .05), but not with immune cell number and phenotype. Diabetes duration is associated with increased number of circulating immune cells (P < .05), inflammatory proteome (P < .05), and negatively associated with adaptive immune response against Mycobacterium tuberculosis and Rhizopus oryzae (P < .05). Diabetes nephropathy is associated with increased circulating immune cells (P < .05) and inflammatory markers (P < .05).CONCLUSION:Disease duration and chronic complications associate with persistent alterations in the immune response of individuals with long standing T1D.

COVID-19 patients have increased risk of pulmonary embolism (PE), but symptoms of both conditions overlap. Because screening algorithms for PE in COVID-19 patients are currently lacking, PE might be underdiagnosed. We evaluated a screening algorithm in which all patients presenting to the ED with suspected or confirmed COVID-19 routinely undergo D-dimer testing, followed by CT pulmonary angiography (CTPA) if D-dimer is ≥ 1.00 mg/L. Consecutive adult patients presenting to the ED of two university hospitals in Amsterdam, The Netherlands, between 01-10-2020 and 31-12-2020, who had a final diagnosis of COVID-19, were retrospectively included. D-dimer and CTPA results were obtained. Of 541 patients with a final diagnosis of COVID-19 presenting to the ED, 25 (4.6%) were excluded because D-dimer was missing, and 71 (13.1%) because they used anticoagulation therapy. Of 445 included patients, 185 (41.6%; 95%CI 37.0–46.3) had a D-dimer ≥ 1.00 mg/L. CTPA was performed in 169 of them, which showed PE in 26 (15.4%; 95%CI 10.3–21.7), resulting in an overall detection rate of 5.8% (95%CI 3.9–8.4) in the complete study group. In patients with and without PE at CTPA, median D-dimer was 9.84 (IQR 3.90–29.38) and 1.64 (IQR 1.17–3.01), respectively (p < 0.001). PE prevalence increased with increasing D-dimer, ranging from 1.2% (95%CI 0.0–6.4) if D-dimer was 1.00–1.99 mg/L, to 48.6% (95%CI 31.4–66.0) if D-dimer was ≥ 5.00 mg/L. In conclusion, by applying this screening algorithm, PE was identified in a considerable proportion of COVID-19 patients. Prospective management studies should assess if this algorithm safely rules-out PE if D-dimer is < 1.00 mg/L.

Hyperammonaemia is often encountered in acute neurology and can be the cause of acute or chronic neurological symptoms. Patients with hyperammonaemia may present with seizures or encephalopathy, or may be entirely asymptomatic. The underlying causes are diverse but often straightforward to diagnose, although sometimes require specialist investigations. Haemodialysis or haemo(dia)filtration is the first-line treatment for acute severe hyperammonaemia (of any cause) in an adult. Here we discuss our approach to adult patients with hyperammonaemia identified by a neurologist.

The role of the insulin receptor in mediating tissue-specific insulin clearance in vivo has not been reported. Using physiologic insulin doses, we measured the initial clearance rate (first 5 min) of intravenously injected ([125I]TyrA14)-insulin by muscle, liver, and kidney in healthy rats in the presence and absence of the insulin receptor blocker S961. We also tested whether 4 weeks of high-fat diet (HFD) affected the initial rate of insulin clearance. Pre-treatment with S961 for 60 min prior to administering labeled insulin raised plasma ([125I]TyrA14)insulin concentration approximately 5-fold (p < 0.001), demonstrating receptor dependency for plasma insulin clearance. Uptake by muscle (p < 0.01), liver (p < 0.05), and kidney (p < 0.001) were each inhibited by receptor blockade, undoubtedly contributing to the reduced plasma clearance. The initial plasma insulin clearance was not significantly affected by HFD, nor was muscle-specific clearance. However, HFD modestly decreased liver clearance (p = 0.056) while increasing renal clearance by >50% (p < 0.01), suggesting a significant role for renal insulin clearance in limiting the hyperinsulinemia that accompanies HFD. We conclude that the insulin receptor is a major mediator of initial insulin clearance from plasma and for its clearance by liver, kidney, and muscle. HFD feeding increases renal insulin clearance to limit systemic hyperinsulinemia.

Objective The mechanisms underlying the development of peripheral insulin resistance are complex. Several studies have linked sclerostin, an osteocyte-derived inhibitor of the Wnt/β-catenin pathway, to obesity and insulin resistance. The aim of this study was to investigate (1) whether serum sclerostin is associated with insulin sensitivity in lean and/or obese women; and (2) whether hyperinsulinaemia affects serum sclerostin concentrations. Design A cross-sectional study. Methods Insulin sensitivity was measured in lean (BMI < 25 kg/m2) and obese (BMI > 30 kg/m2) women using a hyperinsulinaemic–euglycaemic clamp. Serum sclerostin was measured at baseline and during the clamp procedure. Results We studied 21 lean and 22 obese women with a median age of 40 and 43 years and a median BMI of 22.4 and 33.5 kg/m2, respectively. Obese women had higher serum sclerostin than lean women (122 ± 33 vs 93 ± 33 nmol/L, P < 0.01). Higher serum sclerostin was associated with lower insulin sensitivity in obese, but not in lean individuals (difference in M-value between highest and lowest quartile: −7.02 mg/kg/min, P = 0.03 and 1.59 mg/kg/min, P = 0.50, respectively). Hyperinsulinaemia did not affect serum sclerostin in lean nor obese women (P > 0.5). Conclusion Serum sclerostin is negatively associated with insulin sensitivity as measured with the hyperinsulinaemic–euglycaemic clamp in obese, but not lean women. This indicates a potential role of the Wnt/β-catenin pathway in regulating insulin sensitivity particularly in obese individuals. Our findings remain hypothesis-generating and should be confirmed by additional studies.

To clarify the mechanism underlying the described U-shaped relation of both low and high levels of IGF-1 with cardiovascular disease this study explores the effect of decreasing and increasing growth hormone dose in GH deficient adults on (micro)vascular function, body composition and insulin resistance. In this randomized clinical trial, thirty-two subjects receiving GH therapy with an IGF-1 concentration between −1 and 1 SD score (SDS) for at least one year were randomized to receive either a decrease (IGF-1 target level of −2 to −1 SDS) or an increase of their daily GH dose (IGF-1 target level of 1 to 2 SDS) for a period of 24 weeks. Microvascular endothelium (in)dependent vasodilatation and vasomotion, vascular stiffness by pulse wave analysis, and HOMA-IR were measured. At the end of the study 30 subjects (65.6% men, mean age 46.6 (SD 9.9) years) were analyzed. There was a favorable effect of increasing the IGF-1 level on waist circumference compared to decreasing the IGF-1 level (p=0.05), but a detrimental effect on insulin resistance (p=0.03). Decreasing IGF-1 level significantly lowered the endothelial domain of vasomotion (p=0.03), whereas increasing IGF-1 level increased the contribution of the neurogenic domain (p=0.05). This change was related to the favorable change in waist circumference. In conclusion, increasing IGF-1 levels was beneficial for body composition but detrimental with respect to insulin resistance. The contribution of the neurogenic vasomotion domain increased in parallel, and could be explained by the favorable change in waist circumference. Clinical Trial Registration ClinicalTrials.gov, identifier NCT01877512.

Background Diagnostic strategies for suspected pulmonary embolism (PE) have not been prospectively evaluated in COVID-19 patients. Methods Prospective, multicenter, outcome study in 707 patients with both (suspected) COVID-19 and suspected PE in 14 hospitals. Patients on chronic anticoagulant therapy were excluded. Informed consent was obtained by opt-out approach. Patients were managed by validated diagnostic strategies for suspected PE. We evaluated the safety (3-month failure rate) and efficiency (number of computed tomography pulmonary angiographies [CTPAs] avoided) of the applied strategies. Results Overall PE prevalence was 28%. YEARS was applied in 36%, Wells rule in 4.2%, and “CTPA only” in 52%; 7.4% was not tested because of hemodynamic or respiratory instability. Within YEARS, PE was considered excluded without CTPA in 29%, of which one patient developed nonfatal PE during follow-up (failure rate 1.4%, 95% CI 0.04–7.8). One-hundred seventeen patients (46%) managed according to YEARS had a negative CTPA, of whom 10 were diagnosed with nonfatal venous thromboembolism (VTE) during follow-up (failure rate 8.8%, 95% CI 4.3–16). In patients managed by CTPA only, 66% had an initial negative CTPA, of whom eight patients were diagnosed with a nonfatal VTE during follow-up (failure rate 3.6%, 95% CI 1.6–7.0). Conclusion Our results underline the applicability of YEARS in (suspected) COVID-19 patients with suspected PE. CTPA could be avoided in 29% of patients managed by YEARS, with a low failure rate. The failure rate after a negative CTPA, used as a sole test or within YEARS, was non-negligible and reflects the high thrombotic risk in these patients, warranting ongoing vigilance.

Inhibition of dipeptidyl peptidase (DPP-)4 could reduce coronavirus disease 2019 (COVID-19) severity by reducing inflammation and enhancing tissue repair beyond glucose lowering. We aimed to assess this in a prospective cohort study. We studied in 565 patients with type 2 diabetes in the CovidPredict Clinical Course Cohort whether use of a DPP-4 inhibitor prior to hospital admission due to COVID-19 was associated with improved clinical outcomes. Using crude analyses and propensity score matching (on age, sex and BMI), 28 patients using a DPP-4 inhibitor were identified and compared to non-users. No differences were found in the primary outcome mortality (matched-analysis = odds-ratio: 0,94 [95% confidence interval: 0,69 – 1,28], p-value: 0,689) or any of the secondary outcomes (ICU admission, invasive ventilation, thrombotic events or infectious complications). Additional analyses comparing users of DPP-4 inhibitors with subgroups of non-users (subgroup 1: users of metformin and sulphonylurea; subgroup 2: users of any insulin combination), allowing to correct for diabetes severity, did not yield different results. We conclude that outpatient use of a DPP-4 inhibitor does not affect the clinical outcomes of patients with type 2 diabetes who are hospitalized because of COVID-19 infection.

OBJECTIVE:In mice fed a high-fat diet, impairment of insulin signaling in endothelium is an early phenomenon that precedes decreased insulin sensitivity of skeletal muscle, adipose tissue, and liver. We assessed in humans whether short-term overfeeding affects insulin-induced microvascular recruitment in skeletal muscle and adipose tissue before changes occur in glucose uptake and lipolysis. Approach and Results: Fifteen healthy males underwent a hypercaloric and subsequent hypocaloric diet intervention. Before, during, and after the hypercaloric diet, and upon return to baseline weight, all participants underwent (1) a hyperinsulinemic-euglycemic clamp to determine insulin-induced glucose uptake and suppression of lipolysis (2) contrast-enhanced ultrasonography to measure insulin-induced microvascular recruitment in skeletal muscle and adipose tissue. In addition, we assessed insulin-induced vasodilation of isolated skeletal muscle resistance arteries by pressure myography after the hypercaloric diet in study participants and controls (n=5). The hypercaloric diet increased body weight (3.5 kg; P<0.001) and fat percentage (3.5%; P<0.001) but did not affect glucose uptake nor lipolysis. The hypercaloric diet increased adipose tissue microvascular recruitment (P=0.041) and decreased the ratio between skeletal muscle and adipose tissue microvascular blood volume during hyperinsulinemia (P=0.019). Insulin-induced vasodilation of isolated skeletal muscle arterioles was significantly lower in participants compared with controls (P<0.001). The hypocaloric diet reversed all of these changes, except the increase in adipose tissue microvascular recruitment.CONCLUSIONS:In lean men, short-term overfeeding reduces insulin-induced vasodilation of skeletal muscle resistance arteries and shifts the distribution of tissue perfusion during hyperinsulinemia from skeletal muscle to adipose tissue without affecting glucose uptake and lipolysis. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02628301.