Euglycemic Clamp Research Articles

DI/cle, a Measure Consisting of Insulin Sensitivity, Secretion, and Clearance, Captures Diabetic States.

Insulin clearance is implicated in regulation of glucose homeostasis independently of insulin sensitivity and insulin secretion. To understand the relation between blood glucose and insulin sensitivity, secretion, and clearance. We performed a hyperglycemic clamp, a hyperinsulinemic-euglycemic clamp, and an oral glucose tolerance test (OGTT) in 47, 16, and 49 subjects with normal glucose tolerance (NGT), impaired glucose tolerance (IGT), and type 2 diabetes mellitus (T2DM), respectively. Mathematical analyses were retrospectively performed on this dataset. The disposition index (DI), defined as the product of insulin sensitivity and secretion, showed a weak correlation with blood glucose levels, especially in IGT (r = 0.04; 95% CI, -0.63 to 0.44). However, an equation relating DI, insulin clearance, and blood glucose levels was well conserved regardless of the extent of glucose intolerance. As a measure of the effect of insulin, we developed an index, designated disposition index/clearance, (DI/cle) that is based on this equation and corresponds to DI divided by the square of insulin clearance. DI/cle was not impaired in IGT compared with NGT, possibly as a result of a decrease in insulin clearance in response to a reduction in DI, whereas it was impaired in T2DM relative to IGT. Moreover, DI/cle estimated from a hyperinsulinemic-euglycemic clamp, OGTT, or a fasting blood test were significantly correlated with that estimated from 2 clamp tests (r = 0.52; 95% CI, 0.37 to 0.64, r = 0.43; 95% CI, 0.24 to 0.58, r = 0.54; 95% CI, 0.38 to 0.68, respectively). DI/cle can serve as a new indicator for the trajectory of changes in glucose tolerance.

Glucose-dependent inflammatory responses in obese compared to lean individuals

PurposeObesity is characterized by chronic inflammation that may contribute to insulin resistance and promote type 2 diabetes. We have investigated whether inflammatory responses to glycemic and insulinemic variations are altered in obese individuals.MethodsEight obese and eight lean individuals without diabetes had undergone hyperinsulinemic-euglycemic-hypoglycemic and hyperglycemic clamps in a previous study. Using Proximity Extension Assay, 92 inflammatory markers were analyzed from plasma samples at fasting, hyperinsulinemia-euglycemia, hypoglycemia and hyperglycemia.ResultsIn all participants, hyperinsulinemia, hypoglycemia and hyperglycemia led to reductions of 11, 19 and 62 out of the 70 fully evaluable biomarkers, respectively. FGF-21 increased during both hypoglycemia and hyperglycemia while IL-6 and IL-10 increased during hypoglycemia. In obese vs lean participants, Oncostatin-M, Caspase-8 and 4E-BP1 were more markedly suppressed during hypoglycemia, whereas VEGF-A was more markedly suppressed during hyperglycemia. BMI correlated inversely with changes of PD-L1 and CD40 during hyperinsulinemia, Oncostatin-M, TNFSF14, FGF-21 and 4EBP-1 during hypoglycemia and CCL23, VEGF-A and CDCP1 during hyperglycemia (Rho ≤ -0.50). HbA1c correlated positively with changes of MCP-2 and IL-15-RA during hyperinsulinemia (Rho ≥ 0.51) and inversely with changes of CXCL1, MMP-1 and Axin-1 during hypoglycemia (Rho ≤ -0.55). M-value correlated positively with changes of IL-12B and VEGF-A during hyperglycemia (Rho ≥ 0.51). Results above were significant (p < 0.05).ConclusionOverall, hyperinsulinemia, hypo- and hyperglycemia led to suppression of several inflammatory markers and this tended to be more marked in individuals with obesity, insulin resistance and dysglycemia. Thus, acute glycemic or insulinemic variations do not seem to potentiate possible inflammatory pathways in the development of insulin resistance and disturbed glucose metabolism.

Plasma insulin is required for the increase in plasma angiopoietin-like protein 8 in response to nutrient ingestion.

Plasma levels of angiopoietin-like protein 8 (ANGPTL8) are regulated by feeding and they increase following glucose ingestion. Because both plasma glucose and insulin increase following food ingestion, we aimed to determine whether the increase in plasma insulin and glucose or both are responsible for the increase in ANGPTL8 levels. ANGPTL8 levels were measured in 30 subjects, 14 with impaired fasting glucose (IFG), and 16 with normal fasting glucose (NFG); the subjectsreceived 75g glucose oral Glucose tolerance test (OGTT), multistep euglycaemic hyperinsulinemic clamp and hyperglycaemic clamp with pancreatic clamp. Subjects with IFG had significantly higher ANGPTL8 than NGT subjects during the fasting state (p<0.05). During the OGTT, plasma ANGPTL8 concentration increased by 62% above the fasting level (p<0.0001), and the increase above fasting in ANGPTL8 levels was similar in NFG and IFG individuals. During the multistep insulin clamp, there was a dose-dependent increase in plasma ANGPTL8 concentration. During the 2-step hyperglycaemic clamp, the rise in plasma glucose concentration failed to cause any change in the plasma ANGPTL8 concentration from baseline. In response to nutrient ingestion, ANGPTL8 level increased due to increased plasma insulin concentration, not to the rise in plasma glucose. The incremental increase above baseline in plasma ANGLPTL8 during OGTT was comparable between people with normal glucose tolerance and IFG.

1784-PUB: Empagliflozin (EMPA) Enhances Vascular Insulin Sensitivity and Lowers Plasma ICAM in Subjects with Type 2 Diabetes (T2D)

Background: The mechanism(s) by which sodium-glucose cotransporter 2 inhibitor (SGLT2i) use improves cardiovascular and renal outcomes in T2D are not well-defined. We hypothesized that EMPA would increase vascular insulin sensitivity and decrease endothelial cell (EC) stress markers in T2D. Study Design: Ten 18-60 years-old persons with T2D, 6.5 &amp;lt; a1c 3 months, were studied. we measured vascular stiffness (pulse wave separation analysis), ec function (flow-mediated dilation (fmd)), and stress biomarkers (elisa) before after a 2-hour, 1 mu min kg euglycemic clamp at 0 12 weeks treatment with 10 mg empa daily. results: not wk 0, but wks, insulin decreased forward backward arterial pressures from 28±3 to 20±2 24±3 13±1 mmhg, respectively, (p&amp;lt;0.02, each) improved the fmd response (p="0.02)," indicating function. peripheral systolic diastolic unchanged by week declined (p&amp;lt;0.03, treatment. lowered baseline post-insulin plasma icam-1 (p&amp;lt;0.002, increased vcam-1 (p&amp;lt;0.0005). infusion pecam-1 (p&amp;lt;0.03) vasoconstrictor endothelin-1 (p&amp;lt;0.01) comparably or without e-selectin s100a8 9 did change significantly either empa. decrease suggests that inflammation. insulin’s action lower appeared independent of empa, may contribute empa’s beneficial actions. Interpretation: EMPA for 12 weeks enhanced insulin’s action to: 1) diminish arterial stiffness, 2) enhance EC function including biomarker release, and 3) lower blood pressure. Improved vascular insulin sensitivity may contribute to the improved CVD outcomes seen with SGLTi treatment. Disclosure T.Nguyen: None. L.Jahn: None. L.Hartline: None. K.W.Aylor: None. E.Barrett: None. Funding National Institutes of Health (R01HL142250)

376-OR: Chronic Pancreatitis Does Not Induce Specific Alterations in Beta-Cell Function

Chronic pancreatitis (CP) is the most frequent cause of diabetes due to pancreatic diseases, known as type 3c diabetes mellitus (T3cDM). Although the specific alterations of T3cDM are not completely understood, individuals with T3cDM are considered affected by pancreatic endocrine insufficiency and often treated with insulin. To investigate the functional alterations of T3cDM, we evaluated differences in beta-cell function in patients with and without CP, classified according to their glucose tolerance (NGT, IGT, DM). We recruited 50 patients with CP and 96 individuals without CP (NCP). All participants underwent OGTT, hyperglycemic clamp (HC), hyperinsulinemic euglycemic clamp and mixed meal test (MMT) with measurement of GLP-1 and glucagon. Basal insulin secretion rate (ISR), total ISR, rate secretion and β-cell glucose sensitivity (RS and GS) were estimated by mathematical models from OGTT, MMT and HC. Comparing individuals classified into NGT, IGT or DM based on OGTT-derived glucose tolerance, we did not find any difference in beta-cell function derived by OGTT and MMT within the same category (e.g.: NGT-CP vs. NGT-NCP). GLP-1 and glucagon secretion during MMT was not significantly different between CP vs. NCP. Of note, we found that insulin secretion after arginine stimulus in HC, an indirect measure of beta-cell mass, was reduced only in DM-CP vs. DM-NCP (ARG CP 397 (132; 662) pmol/l vs NCP 795 (604; 1134) pmol/l; p= 0.023). No difference was found in insulin sensitivity evaluated as glucose uptake during euglycemic clamp. At equivalent levels of glucose tolerance, patients with CP had similar beta-cell function, GLP-1 and glucagon secretion to individuals without CP. People with T3cDM have less beta-cell mass than patients with DM without CP, but analogous residual beta-cell function, so they could benefit from other therapies apart from insulin. Future studies are warranted to investigate differences in beta-cell function decline between type 2 diabetes mellitus and T3cDM. Disclosure G.Ciccarelli: None. G.Di giuseppe: None. F.Cinti: None. A.Mari: Consultant; Eli Lilly and Company. T.Mezza: None. A.Giaccari: Speaker's Bureau; Abbott, AstraZeneca, Boehringer-Ingelheim, Eli Lilly and Company, Merck Sharp &amp; Dohme Corp., Novo Nordisk, Sanofi.

1754-P: Reduced Incretin Effect Predicts Diabetes Appearance in a Cohort of Nondiabetic Subjects after Acute Beta-Cell Mass Reduction

In type 2 diabetes incretin effect (IE) is reduced but still contributes to 20-35% of insulin response to oral glucose. One reason is the impairment of GIP and GLP1 effects. The role of IE in nondiabetic people is still under debate. In this study we evaluated changes in GLP1 levels, differential β-cell responses and IE during oral vs intravenous stimuli in nondiabetic humans before and after pancreatoduodenectomy (PD). We enrolled 37 nondiabetic patients affected by periampullary nonmalignant neoplasms scheduled for PD. Subjects underwent a 2-h hyperglycemic clamp (HC), a 830 kcal mixed meal test (MMT), and an oral glucose tolerance test (OGTT) before and after PD. GLP1 secretion was calculated during MMT stimulation. β-cell glucose sensitivity (βCGS, pmol·min−1m−2·mM−1) was calculated as the ratio of insulin secretion and glucose increments during both HC and MMT. IE was calculated as the ratio of βCGS obtained during MMT and HC. Based on post-PD OGTT, we divided nondiabetic subjects into 3 groups according to glucose tolerance after PD: normal glucose tolerance (postNGT, n=11), impaired glucose tolerance (postIGT, n=15), or diabetes (postDM, n=11). Before surgery, postIGT subjects exhibited increased GLP1 secretion during MMT compared to the other 2 groups (GLP1 AUC: postIGT 12638±688 vs postNGT 6994±1773 vs postDM 6443±1687 pmol/L·min, P&amp;lt;0.05). Further, a similar βCGS was observed in the 3 groups following HC stimulation (postNGT 95.2±15.5 vs postIGT 64.3±8.72 vs postDM 73.8±11.8, P=0.2), while a scaled reduction in βCGS was observed in postIGT and post-DM following MMT (postNGT 206±50.0 vs postIGT 111±19.9 vs postDM 88.2±8.45, P&amp;lt;0.05). Accordingly, we observed a scaled reduction of IE in postIGT and postDM groups (postNGT 2.35±0.52 vs post-IGT 1.37±0.13 vs post-DM 0.86±0.18, P&amp;lt;0.05). Our data show that GLP1 secretion increases in people at risk of IGT, possibly to compensate reduced IE, which seems to predict DM appearance after β-cell mass reduction. Disclosure G.Di giuseppe: None. J.J.Holst: Advisory Panel; Novo Nordisk A/S, Eli Lilly and Company, Board Member; Bainan Biotech, Antag Therapeutics, Consultant; Alphasights, Eli Lilly and Company, ShouTi Pharma Inc., Zealand Pharma A/S, Other Relationship; Novo Nordisk, Novo Nordisk Pharma, Mayo Clinic, Boehringer-Ingelheim, Scohia Pharma Inc., Research Support; ARLA, European Union, Novo Nordisk Foundation. A.Giaccari: Speaker's Bureau; Abbott, AstraZeneca, Boehringer-Ingelheim, Eli Lilly and Company, Merck Sharp &amp; Dohme Corp., Novo Nordisk, Sanofi. T.Mezza: None. C.Cefalo: None. S.Moffa: None. G.Ciccarelli: None. L.Soldovieri: None. F.Cinti: None. U.Capece: None. F.Impronta: None. A.Mari: Consultant; Eli Lilly and Company. Funding Università Cattolica del Sacro Cuore; European Foundation for the Study of Diabetes; Ministero della Salute

68-LB: Early Pharmacological Intervention (EPIC) to Preserve Beta-Cell Function in Prediabetes (PreDM)

Beta cell failure is the key pathophysiologic determinant in progression from PreDM to type 2 diabetes (T2D). Lifestyle modifications frequently are insufficient to prevent T2D onset and drugs that modify disease progression by targeting pathophysiologic defects in PreDM may be required. Methods: EPIC seeks to answer whether a specific drug provides greater benefit to prevent PreDM progression and to assess the effect of two years of treatment with antidiabetic drugs in 200 individuals with IFG and/or IGT on insulin sensitivity (IS) and beta cell function (BCF). At baseline, participants received 2h-OGTT and two-step hyperglycemic clamp (HC) (+125 and +400 mg/dl) with GLP-1RA infusion. Subjects then were randomized to metformin (MET), pioglitazone (PIO), saxagliptin (SAXA) or dapagliflozin (DAPA). 55 participants have completed the intervention (35F/20M; age = 51 ± 3 ys) Matsuda Index of IS was quantitated from OGTT. Beta Cell Function (BCF) was quantitated: (i) from OGTT as (ΔC-Pep/ΔG) x (Matsuda) and (ii) from HC as ΔC-Pep (First Phase, AIR x Matsuda; ΔC-Pep (Second Phase, +400 mg/dL x Matsuda; and (Second Phase + Exenatide) x Matsuda. Results: A1c did not change significantly in any group, while FPG (106 ±4 to 100 ± 3 mg/dl) and 2h PG (150 ±8 to 141 ± 11) decreased significantly in all groups (p&amp;lt;0.05 for PIO &amp;gt; SAXA). Matsuda Index increased in all groups (p&amp;lt;0.01 for PIO vs all other groups). Weight increased significantly in PIO (+2.5kg p&amp;lt;0.05), did not change with SAXA, decreased with DAPA and MET (both p = NS). BCF during OGTT tended to increase in all groups (p&amp;lt;0.10 for trend). No significant changes in AIR, second phase (+400 mg/dl), and second phase (+400) + Exenatide were seen for MET, SAXA, DAPA, but significantly increased with PIO (AIR 7.1 to 22.8; 2ND STEP 10 to 45.4; 2nd STEP + Exenatide 19 to 79 (all p &amp;lt;0.01). Conclusion: Early drug intervention in prediabetes with pioglitazone preserves beta cell function and improves insulin sensitivity better than MET, SAXA, and DAPA. Disclosure A. Chavez: None. A. Merovci: None. S. Neppala: None. L. A. Cruz Moreno: None. G. Baskoy: None. F. M. Acosta: None. A. A. Hansis-Diarte: None. C. L. Puckett: None. J. M. Adams: None. M. Abdul-Ghani: None. C. L. Triplitt: Speaker's Bureau; Novo Nordisk. E. Cersosimo: None. R. A. DeFronzo: Speaker's Bureau; AstraZeneca. Advisory Panel; AstraZeneca, Bayer Inc., Boehringer-Ingelheim, Novo Nordisk. Research Support; AstraZeneca, Boehringer-Ingelheim, Merck &amp; Co., Inc. Funding National Institutes of Health (R01DK024092-3AZ, ISSDAPA0002)

1600-P: Duration of Morning Hyperinsulinemia Is Key to the Enhancement of Hepatic Glucose Uptake Later in the Day

The second meal phenomenon, which occurs in normal and diabetic individuals, refers to the improvement in glucose tolerance seen following a second identical meal. We previously showed that 4h of morning (AM) hyperinsulinemia, but not hyperglycemia, enhanced hepatic glucose uptake (HGU) and glycogen storage during a PM hyperinsulinemic hyperglycemic clamp (HIHG) later that day. Our aim was to determine if the duration of morning hyperinsulinemia is important for the PM response to a HIHG clamp. To determine this, we administered the same amount of insulin over 2h in the first half of the morning (Ins2h-A), over 2h in the 2nd half of the morning (Ins2h-B), or over the entire 4h (Ins4h) of the morning. We then assessed the impact of the AM insulin duration on HGU during a PM HIHG clamp in conscious dogs. The dogs underwent an AM hyperinsulinemic euglycemic clamp from 0-120 min, 120-240 min, or 0-240 min (Ins2h-A, Ins2h-B, or Ins4h; n=6/group). The insulin infusion rates used in the Ins4h were selected to mimic the rise in endogenous insulin secretion previously observed during a 4h AM duodenal glucose infusion (2.1 mU/kg/min (0-30 min), 2.4 mU/kg/min (30-60 min), and 1.5 mU/kg/min (60-240 min)). These rates were doubled in both 2h groups to match the total amount of insulin being infused in the 4h AM clamp. In the PM, all groups had 4x basal insulin, 2x basal glycemia, and portal glucose infusion to simulate a 2nd meal. During the 4h PM clamp, there were no significant differences between the two 2h groups. However, there was a marked effect on the mean HGU in the Ins4h group compared to the Ins2h-A and Ins2h-B groups (HGU of 6.3±0.9 vs 3.8±0.3 and 4.4±0.4 mg/kg/min; AUC of 1393±199 vs 822±68 and 971±93 mg/kg/4hr, P&amp;lt;0.05), respectively, despite matched hepatic glucose loads. The longer duration (Ins4h) of AM hyperinsulinemia allowed for a 41% and 66% greater uptake of glucose in the PM clamp (vs Ins2hA + B). Thus, the duration of AM hyperinsulinemia is an important determinant of hepatic metabolism later in the day. Disclosure H.L.Waterman: None. M.S.Smith: None. B.Farmer: None. G.Kraft: None. M.Scott: None. D.S.Edgerton: None. A.D.Cherrington: Advisory Panel; Metavention, vTv Therapeutics, Diakard, Sekkei Bio, Sensulin Labs, LLC, Other Relationship; Fractyl Health, Inc., Novo Nordisk, Abvance Therapeutics, Research Support; Cellular Longevity, Inc, dba Loyal, Senda Biosciences. M.C.Moore: None. Funding National Institutes of Health (5T32DK007563-34, 5R01DK131082-02)

302-OR: How Menstrual Cycle Impacts Brain Insulin Action—Results from Young Women

The human brain is an insulin-sensitive organ that modulates whole-body glucose metabolism and adiposity. In case of brain insulin resistance, this regulation is disturbed. In the periphery, insulin sensitivity varies along the menstrual cycle, while the effects on brain insulin action are still unknown. We here investigated the impact of menstrual cycle on brain insulin sensitivity of the human hypothalamus and on brain-derived modulation of peripheral metabolism. In 26 naturally cycling women (age 19-29 years, BMI 18-24 kg/m2), brain insulin action was assessed in both the follicular and the luteal phase using nasal application of 160 U insulin. In fifteen women, we assessed hypothalamic insulin responsiveness by functional MRI combined with nasal insulin. In eleven women, brain-derived modulation of peripheral insulin sensitivity was studied by hyperinsulinemic euglycemic clamps combined with insulin vs placebo spray. Only in the follicular phase, nasal insulin significantly decreased hypothalamic blood flow (p=0.02), indicating proper brain insulin action. In the luteal phase, insulin induced no such effect (p=0.6). During hyperinsulinemic euglycemic clamps in the follicular phase, more glucose had to be infused after insulin compared to placebo spray. This difference remained significant after adjustment for circulating glucose and insulin (p&amp;lt;0.0001), which was not the case in the luteal phase (p=0.1). High estradiol/progesterone ratio, as present during the follicular phase, was linked to a stronger effect of insulin spray on glucose infusion rates than placebo. Brain insulin sensitivity is a regulated process that can rapidly adapt to changing physiologic requirements, as through the menstrual cycle. In the luteal phase, we detected hypothalamic insulin resistance, which likely contributed to the lacking modulation of peripheral insulin sensitivity through brain insulin delivery. Thus, brain insulin resistance could contribute to whole-body insulin resistance in the luteal phase. Disclosure J.Hummel: None. M.Roden: Advisory Panel; Eli Lilly and Company, Consultant; TARGET PharmaSolutions, Inc., Research Support; Boehringer-Ingelheim, Novo Nordisk, Novartis, Sanofi. H.Häring: None. A.Fritsche: Advisory Panel; Novo Nordisk, Lilly, Sanofi, Boehringer-Ingelheim, Speaker's Bureau; AstraZeneca, SYNLAB Holding Deutschland GmbH. A.Peter: None. R.Wagner: Advisory Panel; Daiichi Sankyo, Speaker's Bureau; Novo Nordisk, Sanofi. S.Kullmann: None. M.Heni: Advisory Panel; Boehringer-Ingelheim, Sanofi, Research Support; Boehringer Ingelheim Inc., Speaker's Bureau; Lilly, Bayer Inc., Sanofi, Boehringer-Ingelheim, Novo Nordisk, Amryt Pharma Plc. C.Benkendorff: None. L.Fritsche: None. K.Prystupa: Other Relationship; Berlin-Chemie AG. A.Vosseler: None. S.Gancheva: Consultant; Novo Nordisk, Bayer Inc. S.Trenkamp: None. A.L.Birkenfeld: None. H.Preissl: None. Funding German Federal Ministry of Education and Research

251-LB: Association of Plasma Sphingolipids with Insulin Secretion and Insulin Sensitivity in Healthy Black and White Adults

Objective: Sphingolipid (SPL) are associated with glucose dysregulation. Here, we examined plasma SPL profiles in relation to insulin action and secretion in Black and White adults. Methods: Baseline plasma levels of 58 SPLs (ceramides {CER}, monohexosyl-ceramides {MHC}, sphingomyelins {SM}, sphingosine {SO} and dihydro-SO-1-phosphate {DHS1P}) were assayed using LC-MS/MS. Insulin sensitivity was assessed by euglycemic clamp (ISI) and HOMA-IR; insulin secretion by IVGTT (AIR), HOMA-B and disposition index (DI, i.e, AIR × ISI). Results: We enrolled healthy offspring of parents with T2DM (75 Black, 65 White; mean age 47.7 ± 9.01 y, BMI 30.4 ± 6.12 kg/m2, FPG 92.9 ± 6.86 mg/dl and 2-hrPG 130 ± 28.8 mg/dl. Total SPLs showed no association with ISI or HOMA-IR but was significantly associated with insulin secretion (AIR, r=0.19, P=0.031; DI r=0.21, P=0.038). There were differential associations between individual SPLs and insulin secretion/sensitivity, but 5 of 58 SPLs (SM C16:0, SM C28:0, SM C28:1, SM C30:1 and SM C34:0) showed concurrent associations with both measures (r=0.16-0.37, P=0.04-&amp;lt;0.0001). Four SPLs were significantly associated with insulin secretion corrected for insulin sensitivity: MHC C14:0 (r=0.24, P=0.016); MHC C26:0 (r=0.23, P=0.025); SM C22:0 (r=0.26, P=0.009); DHS1P (r=0.27, P=0.006). Very long chain SMs correlated with BMI, waist circumference, body fat and lean mass (r=0.19-0.25, P=0.03-0.0004). Plasma CERs and SMs showed significant associations with 2hrPG (r=0.17-0.25, P=0.04-0.003) but not FPG. Conclusion: Circulating SPLs associate differentially with indices of insulin sensitivity, secretion, and adiposity. Of the 58 individual SPLs assayed, MHC C14:0 and C26:0, SM C22:0 and DHS1P showed the strongest association with insulin secretion corrected for insulin sensitivity. Disclosure P. Asuzu: None. N. Mandal: None. J. Y. Wan: None. F. B. Stentz: None. S. Dagogo-jack: None.

223-LB: Associations between Genetic Risk for Insulin Resistance and Measured Insulin Sensitivity Are Impacted by Race and BMI Status

African Americans (AA) are at greater risk for type 2 Diabetes (T2D) compared to European Americans (EA). This greater risk may derive in part from genetic factors. The genetic risk for insulin resistance (IR) has been linked to the failure to expand adipose tissue and is reflected in a genetic risk score (GRS) that is inversely associated with adiposity. In this study, we investigated whether associations between the GRS and measured insulin sensitivity (IS) differ by BMI status and/or race in a sample of 107 EA and AA adults without diabetes. IS was measured with the euglycemic clamp with an insulin dose of 120 µU/m²/min/kg lean body mass. In addition, surrogate indices of IS were calculated using glucose and insulin values obtained from an oral glucose tolerance test. Participants were classified as “high” or “low” BMI using the sample median (25.9 kg/m^2) as the cut-point. GRS were derived from imputed genotypes and weighted for clamp-derived IS. Multiple linear regression models were used to assess interactions between BMI status and GRS on measures of IS. Models were stratified by race and adjusted for percent body fat, sex, and age. In EA, associations of GRS with HOMA-IR and Matsuda differed by BMI status (pint=0.024 and pint=0.007, respectively), where GRS was inversely associated with IS in the high BMI group only (p=0.027 and p=0.010, respectively), suggesting that genetic risk for IR in EA is driven by greater adiposity. Conversely in AA, associations of GRS with IS from the clamp differed by BMI status (pint=0.083), but an inverse association was observed only in the low BMI group (p=0.035), suggesting that in AA, genetic risk for IR is associated with lower adiposity. Our results indicate that obesity status may differentially impact the link between genetic risk for IR and measured IS within and between races. Further, these results suggest that with a larger sample, a distinct phenotype may exist in AA where higher adiposity permits greater IS. Disclosure M. L. Yurchishin: None. L. A. Fowler: None. V. Parcha: None. P. Arora: None. W. Garvey: Advisory Panel; Boehringer-Ingelheim, Novo Nordisk, Eli Lilly and Company, Merck &amp; Co., Inc., Alnylam Pharmaceuticals, Inc., Fractyl Health, Inc. Research Support; Novo Nordisk, Eli Lilly and Company, Epitomee, Pfizer Inc. Advisory Panel; Inogen. Research Support; Neurovalens. B. Gower: Consultant; Abbott.

250-LB: Ethnic Disparities in Insulin Secretion and Clearance in Normoglycemic Adults with Parental Type 2 Diabetes

Background: To determine the role of ethnicity vs. heredity in glucoregulation, we assessed insulin secretion in healthy Black and White offspring of parents with T2DM. Methods: Participants were screened with 75-g OGTT, and normoglycemic enrollees underwent assessments, including anthropometry, insulin sensitivity and secretion. Basal insulin secretion (fasting insulin {FI} and HOMA-B) and dynamic secretion (insulinogenic index; corrected insulin response {CIR} from OGTT data; acute insulin response to i.v. glucose {AIR}, insulin-AUC during FSIGT, and disposition index {DI} were quantified. Insulin sensitivity (ISI) was measured with euglycemic clamp. Basal insulin clearance (molar ratio of fasting C-peptide to insulin) and dynamic clearance (molar ratio of plasma C-peptide to insulin levels during FSIGT) were determined. Results: We studied 145 Black and 123 White adults (N=268); 72% women; mean age 44.6±10.1 y. At baseline, fasting glucose (91.0 ± 7.26 vs.93.1 ± 6.31 mg/dl, P=0.012) and ISI (0.062 ± 0.048 vs. 0.077 ± 0.04, P=.014) were lower, and BMI (31.6 ± 7.64 vs. 28.9 ± 6.79, P=.0032) higher, in Black vs. White subjects. Basal insulin secretion was similar, but all measures of dynamic secretion were higher in Black vs. White offspring (Table 1). Conclusions: Insulin clearance is lower but dynamic insulin secretion is greater in Black versus White individuals with parental diabetes. Disclosure P. Asuzu: None. A. Patel: None. J. Y. Wan: None. S. Dagogo-jack: None.

805-P: Double-Blind Crossover Study of Ultra-Rapid AT247 Compared with NovoLog and Fiasp during Continuous Subcutaneous Infusion (CSII) Assessed by a Hyperinsulinemic Euglycemic Clamp

Background: AT247 is a novel insulin aspart formulation designed for ultra rapid absorption following subcutaneous injection to achieve optimal postprandial glycemic control. Method: Adults (29) with T1DM were randomized to 6 treatment sequences of AT247, Novolog (N), and Fiasp (F). Bolus (0.15 U/kg) and basal (0.02 U/kg/h) doses of insulin were administered via CSII for 3 days. PK and PD were assessed using euglycemic clamps on days (D) 1 and 3. Results: A higher early insulin exposure (AUCIns 0-30min mU/L/h) was observed for AT247 (16.7) vs N (6.3*) or F (13.0**) on D1, Fig 1A. The difference for AT247 was maintained on D3 (20.8) vs N (10.5*) but not vs F (19.2). A higher early glucose lowering effect (AUCGIR 0-60 mins mg/kg) was observed for AT247 (144.4) vs N (70.4*) but not vs F (145.8) on D1 only, Fig 1B. Time to early 50% Cmax insulin (h) occurred earlier for AT247 (0.18) compared to N (0.43*) and F (0.28**) on D1 and D3 (AT247 0.17; N 0.33**; F 0.22**). Statistical significance was p&amp;lt;0.05* or p&amp;lt;0.01**. AT247 was well tolerated with no significant adverse effects. Conclusions: The faster absorption of AT247 resulted in higher early insulin exposure than for F or N following bolus dose delivery during CSII. The demonstrated PK profile of AT247 supports further investigation into its potential to further improve automated insulin delivery. Disclosure M.Hompesch: Board Member; ProSciento, Consultant; Wiley-Blackwell, Employee; ProSciento, Stock/Shareholder; ProSciento. F.J.Lawrence: None. J.Jezek: None. D.J.Gerring: Employee; Arecor. T.Pieber: Advisory Panel; Arecor, Novo Nordisk A/S, Consultant; Lilly, Research Support; AstraZeneca, Novo Nordisk A/S, Sanofi, Speaker's Bureau; Roche Diagnostics.

133-OR: Insulin Dynamics across the Glucose Tolerance Spectrum in Youth with Obesity

Despite β-cell failure in youth with dysglycemia (DYSG) (IGT + T2D), fasting insulin concentrations are elevated. Here, we examined 1) metabolic clearance rate of insulin (MCRI) in youth with normal glucose tolerance (NGT) and DYSG, 2) racial/ethnic differences in insulin dynamics and 3) physical and metabolic correlates of MCRI. In 95 Black (B) + 111 White (W) youth, age 14.4 ± 2.0 [SD] yrs., BMI 34.7 ± 6.4 kg/m2, MCRI and peripheral insulin sensitivity (PIS) were calculated from the hyperinsulinemic-euglycemic clamp, 1st-phase insulin (1stPhI) from the hyperglycemic clamp, disposition index (DI=PIS x 1stPhI), % body fat by DXA, visceral adipose tissue (VAT) by MRI. In DYSG vs NGT, MCRI was lower (261.6 ± 11.9 vs 334.1 ± 8.5 ml/m2/min, p&amp;lt;0.001) and fasting insulin was higher (46.9 ± 4.4 vs 32.9 ± 1.2 μU/mL, p&amp;lt;0.001). In B vs W youth (Image), MCRI was lower driven by DYSG. Lower PIS, lower MCRI and higher 1stPhI were characteristics of B youth with DYSG vs W with equally impaired DI. In B and W youth, positive correlates of MCRI were PIS and DI and negative correlates were fasting insulin, % body fat and VAT. In conclusion, higher fasting insulin concentrations in DYSG despite a failing β-cell could be explained by decreased MCRI. Racial/ethnic contrast in insulin dynamics differs by glycemic status and is more pronounced in DYSG manifested by lower PIS and lower MCRI in B vs W youth with no difference in β-cell function relative to insulin sensitivity. Disclosure W.Cho: None. F.Bacha: Other Relationship; Takeda Pharmaceutical Co., Ltd., AstraZeneca. H.M.Tfayli: Other Relationship; Novo Nordisk, Research Support; Sanofi, Novartis. S.Lee: None. S.Michaliszyn: None. J.Kim: None. S.A.Arslanian: Advisory Panel; Novo Nordisk, Eli Lilly and Company, Consultant; Société des Produits Nestlé SA,, Other Relationship; Eli Lilly and Company, AstraZeneca, Research Support; Novo Nordisk, Eli Lilly and Company. Funding American Diabetes Association (7-08-JF-27 to S.L.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (K24HD01357, R01HD27503); National Center for Advancing Translational Sciences (UL1TR000005); National Center for Research

1547-P: The Differential Effect of Glucagon-Like Peptide-1 Receptor Blockade on Glucose Metabolism in People With and Without Type 2 Diabetes

Glucagon-Like Peptide-1 (GLP-1) is present within the islet but the effects of GLP-1 Receptor (GLP1R) blockade on islet function in humans remains unknown. To address this, we studied 12 nondiabetic individuals (54 ± 2 years, 33 ± 1 kg/m2) and 11 people with type 2 diabetes (DM2 - 58 ± 2 years, 34 ± 2 kg/m2) on 2 occasions in random order. On each occasion, after an overnight fast, [3-3H] glucose was used to measure glucose turnover during fasting and a hyperglycemic clamp (~9 mmol/l) using the tracer dilution technique. On one occasion exendin-9,39 (300pmol/kg/min) was infused to block GLP1R, while on the other saline was infused. Exendin-9,39 increased fasting glucose concentrations in those without (4.6 ± 0.4 vs. 5.5 ± 0.1 mmol/l, saline vs. exendin-9,39 respectively, p = 0.04) and in those with DM2 (7.3 ± 0.5 vs. 8.3 ± 0.6 mmol/l, p = 0.03). Fasting islet hormone concentrations were unchanged, but inappropriate for the higher fasting glucose observed during exendin-9,39 infusion. The same pattern was seen in people with DM2 except that fasting glucagon concentrations increased (8.3 ± 0.5 vs. 10.2 ± 0.6 pmol/l, p &amp;lt; 0.01) and remained elevated throughout hyperglycemia (4.7 ± 0.4 vs. 7.7 ± 0.6 pmol/l, p &amp;lt; 0.02). Insulin secretion rate calculated by deconvolution of C-peptide concentrations was also decreased in DM2 (0.54 ± 0.08 vs. 0.51 ± 0.08 nmol/min, p = 0.02). Consequently, suppression of endogenous glucose production by hyperglycemia was impaired in people with DM2 (2.9 ± 0.4 vs. 5.7 ± 0.3 μmol/kg/min, p &amp;lt; 0.01). Intriguingly, 1st phase response to hyperglycemia was decreased in those without DM2 (3.5 ± 0.6 vs. 2.5 ± 0.5 nmol per 10 min, p = 0.04). These data show that in humans, GLP1R blockade impairs fasting α- and β-cell function resulting in fasting hyperglycemia. Subtle effects are also present in response to hyperglycemia. This implies that intra-islet GLP1R activation sustains islet responses to glucose and it does so to a greater degree in people with DM2. Disclosure A.A. Welch: None. R.A. Farahani: None. M. Zeini: None. A.M. Egan: None. M.C. Laurenti: None. C. Cobelli: None. C. Dalla Man: Research Support; Sanofi-Aventis Deutschland GmbH, Becton, Dickinson and Company. A. Vella: Other Relationship; Novo Nordisk. Advisory Panel; Rezolute, Inc. Consultant; Crinetics Pharmaceuticals, Inc., Hanmi Pharm. Co., Ltd., Zealand Pharma A/S. Funding National Institute of Diabetes and Digestive and Kidney Diseases (R01DK126206)

12-OR: Urine Lactate Is a Disease Biomarker for Diabetic Kidney Disease

As lactate (LA) elevation is associated with mitochondrial dysfunction, we examined the role of LA in diabetic kidney disease (DKD) progression. Urine LA (ULA) was measured in patients with type 2 diabetes (T2D) in three independent cohort studies (HUNT3, SMART2D, and CRIC). ULA and plasma LA (PLA) were also measured in patients with type 1 diabetes (T1D) following eu- or hyperglycemic clamp, in mouse kidney sections, and sodium-glucose cotransporter-2 (SGLT2)-deficient mice. Mitochondrial functional changes in human kidney proximal tubule (HK2) cells were assayed in response to exogenous LA. Subjects in HUNT3 with DKD (n=39) had elevated ULA levels compared to healthy controls (n=53, p=0.023) (Fig. 1). In subjects with T2D from SMART2D (n=230) and CRIC (n=889), the third tertile of ULA/creatinine ratio was associated with a greater estimated glomerular filtration rate (eGFR) decline [-1.63 mL/min/1.73m2/year, p=0.007, and -0.63 mL/min/1.73m2, p=0.042], relative to the first tertile. Acute hyperglycemia stimulated PLA (p&amp;lt;0.0001) and ULA (p=0.001) in patients with T1D (n=39), and in kidney sections incubated with high glucose. Compared to wild-type, SGLT2-deficient mice had lower ULA levels. LA above 2.5 mM inhibited oxygen consumption rate in HK2 cells. Elevated ULA/creatinine ratio inhibits mitochondrial function in diabetes and identifies subjects at risk of rapid renal decline independent of chronic glycemic control. Disclosure L.Kugathasan: None. L.Natarajan: None. S.Lim: None. S.Waikar: None. Y.M.Osman: None. J.He: None. V.Vallon: Research Support; NIH - National Institutes of Health, Gilead Sciences, Inc., Merck Sharp &amp; Dohme Corp., Novo Nordisk, Maze Therapeutics, Boehringer-Ingelheim, Speaker's Bureau; AstraZeneca. S.Hallan: None. D.Cherney: Other Relationship; Boehringer Ingelheim-Lilly, Merck, AstraZeneca, Sanofi, Mitsubishi-Tanabe, Abbvie, Janssen, Bayer, Prometic, BMS, Maze, Gilead, CSL-Behring, Otsuka, Novartis, Youngene, Lexicon and Novo-Nordisk, Research Support; Boehringer Ingelheim-Lilly, Merck, Janssen, Sanofi, AstraZeneca, CSL-Behring and Novo-Nordisk. K.Sharma: Advisory Panel; Reata Pharmaceuticals, Inc., Otsuka America Pharmaceutical, Inc. Cric study investigators: n/a. M.Darshi: Employee; Janssen Research &amp; Development, LLC. V.Srinivasan sridhar: Other Relationship; Merck &amp; Co., Inc. V.Drel: None. J.Tumova: None. J.Liu: None. J.Wang: None. B.A.Perkins: Advisory Panel; Dexcom, Inc., Insulet Corporation, Novo Nordisk, Sanofi, Vertex Pharmaceuticals Incorporated, Other Relationship; Abbott, Medtronic, Sanofi, Research Support; Novo Nordisk, Bank of Montreal (BMO). Y.Lytvyn: None.

1646-P: The Effect of Glucagon-Like Peptide-1 Receptor Blockade and Acute Insulin Resistance on Islet Function and Glucose Metabolism in People without Diabetes

Intra-islet Glucagon-Like Peptide-1 (GLP-1) is increased by islet inflammation and diabetes. GLP-1 Receptor (GLP1R) blockade with exendin-9,39 impairs fasting islet function in people with and without type 2 diabetes (DM2). In addition, it decreases insulin secretion and glucagon suppression in response to hyperglycemia in people with DM2. We sought to examine if free fatty acid (FFA) elevation to induce acute insulin resistance in people without DM2 replicated the effects of GLP1R blockade seen in DM2. We studied 6 nondiabetic individuals (54 ± 4 years, 33 ± 1 kg/m2) on 4 occasions in random order. Glucose metabolism was measured after an overnight fast and during a hyperglycemic clamp (~9 mmol/l) using [3-3H] glucose. On two occasions Intralipid® and heparin were infused to raise FFA. Exendin-9,39 (300pmol/kg/min) was infused to block GLP1R in the presence or absence of FFA elevation, while on the other days saline was infused. In the absence of FFA elevation, exendin-9,39 infusion increased fasting glucose concentrations (5.0 ± 0.1 vs. 5.4 ± 0.1 mmol/l, saline vs. exendin-9,39 respectively, p = 0.01). This pattern was also observed when FFA were elevated (5.3 ± 0.1 vs. 5.7 ± 0.2 mmol/l, p = 0.02). Fasting insulin, C-peptide (without FFA: 0.9 ± 0.1 vs. 0.8 ± 0.1 nmol/l, p = 0.17; with FFA: 1.1 ± 0.1 vs. 1.0 ± 0.1 nmol/l, p = 0.08) and glucagon concentrations were unchanged, but inappropriate for the higher fasting glucose observed during exendin-9,39 infusion. Exendin-9,39 infusion did not alter islet hormone secretion during the clamp in the presence or absence of FFA elevation. The magnitude of changes induced by exendin-9,39 did not differ in the presence or absence of FFA elevation (p &amp;gt; 0.10). These experiments confirm the effects of GLP1R blockade on fasting α- and β-cell function in people without DM2. However, FFA elevation does not replicate the abnormalities of islet function observed in people with DM2 when exendin-9,39 is infused. Disclosure M. Zeini: None. R.A. Farahani: None. A.A. Welch: None. M.C. Laurenti: None. C. Cobelli: None. C. Dalla Man: Research Support; Sanofi-Aventis Deutschland GmbH, Becton, Dickinson and Company. A.M. Egan: None. A. Vella: Other Relationship; Novo Nordisk. Advisory Panel; Rezolute, Inc. Consultant; Crinetics Pharmaceuticals, Inc., Hanmi Pharm. Co., Ltd., Zealand Pharma A/S. Funding National Institutes of Health (DK126206)

1515-P: Effect of Aging on Insulin Clearance in Mice

Aging is commonly linked with hyperinsulinemia and insulin resistance. Age-related hyperinsulinemia results from increased insulin secretion and/or decreased insulin clearance as compensatory mechanisms to peripheral insulin resistance. Several studies have reported reduced β-cell function in elderly rodents and humans. Earlier reports on decreased insulin clearance due to aging suggest that hyperinsulinemia in elderly could be explained predominantly by a reduction in insulin clearance. Hence, we aim to better understand the role of aging on insulin clearance following fat infusion. To investigate the aging effect, 3 months and 10-14 months old C57BL6 mice were infused with ethylpalmitate for 48h (hydrolyzed to palmitate and ethanol in plasma), to achieve elevated circulating FFA in a non-toxic manner. Mice were then subjected to hyperglycemic clamp, and during the clamp plasma C-peptide and insulin were measured to evaluate insulin clearance. Glucose infusion rate (GINF), insulin sensitivity index (SI) and disposition index (DI) were also assessed during clamp analysis. GINF is a measure of glucose tolerance whereas DI evaluates β-cell function. Whereas insulin secretion did not increase, insulin clearance was reduced in the aging mice, as indicated by the lower C-peptide/insulin molar ratio, observed during hyperglycemic clamp. No significant changes were observed in GINF between old and young mice; however, SI and DI were lower in elderly group. These results collectively suggest that with advancing age, β-cells may lose their ability to maintain a higher insulin secretion and that reduced hepatic insulin clearance plays a more dominant role to compensate for age-related decline in insulin sensitivity. Disclosure S.Rahman: None. S.Zaidi: Other Relationship; BullFrog AI. H.T.Muturi: None. S.M.Najjar: None. A.Giacca: None.

51-LB: Race Specific Effects of a Carbohydrate-Restricted Diet on Acute and Maximal C Peptide Response to Glucose in Adults with Type 2 Diabetes

Beta-cell response to glucose is compromised in individuals with type 2 diabetes (T2D), possibly due to lipid infiltration of the pancreas from excessive carbohydrate consumption. This study was conducted to determine if a eucaloric carbohydrate restricted diet (~9% energy from carbohydrate, 65% energy from fat), compared to a eucaloric fat restricted diet (~55% energy from carbohydrate, 20%energy from fat), would improve beta-cell response to glucose in participants with T2D. Participants were 43 African American and European American adults with T2D not using insulin. Medications were discontinued 1-2 weeks (depending upon the medication) prior to baseline testing. A hyperglycemic clamp was used to assess the acute (first-phase) and maximal (arginine-stimulated) C-peptide responses to glucose at baseline and after 12 weeks of controlled diet therapy (all food provided). Based on the detection of a race-by-diet interaction (P=0.06), data were analyzed within each race group. At 12 weeks, a significant effect of diet was observed by ANCOVA on acute C-peptide response in African Americans (2-fold greater with the carbohydrate restricted diet, P&amp;lt;0.05), and on maximal C-peptide response in European Americans (50% greater with the carbohydrate restricted diet, P&amp;lt;0.01), after adjusting for change in body weight. Paired t-test revealed an improvement in acute C-peptide response within African Americans on the carbohydrate restricted diet (P&amp;lt;0.01) from baseline to week 12, and an improvement in maximal C-peptide response within European Americans on the carbohydrate restricted diet (P&amp;lt;0.01). No changes in beta-cell function were observed in response to the fat restricted diet. These results suggest that a carbohydrate restricted diet has beneficial effects on beta-cell function that are race-specific and independent of weight loss. Disclosure B. Gower: Consultant; Abbott. A. M. Goss: Advisory Panel; Novo Nordisk, Consultant; Weight Watchers International. W. Garvey: Advisory Panel; Boehringer-Ingelheim, Novo Nordisk, Eli Lilly and Company, Merck &amp; Co., Inc., Alnylam Pharmaceuticals, Inc., Fractyl Health, Inc., Inogen, Research Support; Novo Nordisk, Eli Lilly and Company, Epitomee, Pfizer Inc., Neurovalens. Funding National Institutes of Health (R01DK116726)

868-P: Empagliflozin (EMPA) Improves Vascular Insulin Sensitivity and Enhances Skeletal and Cardiac Muscle Microvascular Perfusion in Persons with Type 2 Diabetes

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) decreased cardiac events in large clinical trials; however, an understanding of the physiology driving this benefit is lacking. To investigate this, we measured micro- and macrovascular insulin sensitivity in 10 adults with T2DM before and after 12 weeks of EMPA 10 mg daily. We also measured endothelial function (FMD), peripheral and central aortic pressures, and skeletal (SM) and cardiac (CM) muscle microvascular perfusion (MBV- microvascular blood volume; MFV-microvascular flow velocity; MBF-microvascular blood flow) before and during a 120 min euglycemic insulin clamp at weeks 0 and 12. We hypothesized that EMPA would diminish micro- and macro-vascular insulin resistance and improve vascular function. At week 0, insulin infusion lowered peripheral SBP (132±6 vs 125±5, p&amp;lt;0.05) but diminished SM perfusion MBV (1.75±0.2 vs 1.29±0.1, p&amp;lt;0.01) MFV (0.08±0.01 vs 0.05±0.01, p&amp;lt;0.001) and MBF (0.14±3 vs 0.07±0.01, p&amp;lt;0.01). After 12 weeks of EMPA, insulin infusion improved FMD (7.6 ± 1.2 vs 8.7 ±1.6%, p &amp;lt;0.03), lowered peripheral SBP (127±6 vs 107±5, p&amp;lt;0.001); DBP (74±4 vs 65±3, p&amp;lt;0.04); MAP (92±3 vs 79±3, p&amp;lt;0.01); and PP (53±5 vs 42±3, p&amp;lt;0.05) as well as aortic SBP (117±5 vs 96±4, p&amp;lt;0.001); DBP (75±4 vs 66±3, p&amp;lt;0.03); MAP (89±3 vs 76±3, p&amp;lt;0.01); and PP (43±4 vs 30±2, p&amp;lt;0.01). In addition, EMPA improved SM perfusion (MBV: 1.29±0.1 vs 2.02±0.3, p&amp;lt;0.02; MFV: 0.05±0.01 vs 0.08±0.01, p&amp;lt;0.02; MBF: 0.07±0.01 vs 0.18±0.04, p&amp;lt;0.03) and CM perfusion (MBV: 4.51±0.6 vs 5.11±0.4, p=0.18; MFV: 0.37±0.04 vs 0.52±0.06, p&amp;lt;0.05; MBF: 1.80±0.4 vs 2.74±0.5, p&amp;lt;0.05). In conclusion, 12 weeks of EMPA in adults with T2D improved endothelial function (FMD), reduced central and peripheral blood pressures, and augmented SM and CM microvascular perfusion in response to insulin. These changes may contribute to the improved CV outcomes seen with SGLT2i therapy. Disclosure L.Jahn: None. L.Hartline: None. K.W.Aylor: None. W.B.Horton: None. E.Barrett: None. Funding National Institutes of Health (1R01HL142250-01A1)