Clearance Rate Of Insulin Research Articles

Calculated estimation of the metabolic clearance rate of insulin measured by glucose clamp examination in out-patient clinical practice.

A subpopulation of Japanese patients with type 2 diabetes mellitus (T2DM) who have elevated insulin clearance (IC) exists. We tested our hypothesis that it is possible to estimate IC using common and simple test results collected in routine clinical practice. We recruited patients with newly diagnosed, treatment-naïve T2DM and measured the metabolic clearance rate of insulin (MCRI) determined by a hyperinsulinemic-euglycemic clamp examination. Multivariable regression analysis was performed with body mass index (BMI), serum uric acid (UA), and fasting plasma insulin (F-IRI) which were independently associated with IC increase in our previous reports as explanatory variables to calculate a prediction equation for MCRI. We enrolled 101 patients in this study. Because MCRI is not normally distributed, we calculated the logarithmically transformed estimated Log10MCRI as a prediction formula for IC. Multivariable regression analysis showed that Log10BMI (β = - 0.3257, P < 0.001), UA (β = - 0.1834, P = 0.0081), and Log10F-IRI (β = - 0.4367, P < 0.001) were significant independent factors for Log10MCRI. The regression equation was as follows: estimated Log10MCRI = - 0.5421 × Log10BMI - 0.0167 × UA - 0.1792 × Log10F-IRI + 3.8251 (r = 0.7677, R 2 = 0.5894, P < 0.001). IC can easily be predicted using BMI, UA, and F-IRI which are common and simple test results collected in routine clinical practice.

Fetal sex effects on maternal health can now be tested via randomization: A first-in-class illustration in cows on glucoregulatory outcomes

BackgroundThe maternal-offspring relationship, such as whether fetal sex influences maternal health, is essential to explore to advance prenatal and maternal health. While associations exist between fetal sex and maternal health outcomes, it is unclear whether these reflect a causal relationship. ObjectiveTo demonstrate that fetal sex can be randomly assigned to test the causal effect of fetal sex on maternal outcomes. MethodsHolstein dairy cows were stratified and randomized using sealed opaque envelopes to be artificially inseminated with either X- or Y-sorted bull semen until 40 cows became pregnant. Monthly body weight measurements were recorded, and an intravenous glucose tolerance test was performed 30 days before the expected calving day. The primary outcome was insulin area under the curve (AUC), and secondary outcomes were clearance rate, half-life, and AUC for glucose, insulin, and non-esterified fatty acid concentrations. An intention-to-treat (ITT) approach using multiple imputation was employed for primary analysis, and an as-treated (AT) approach was used for secondary analysis. ResultsWe demonstrated that we could successfully randomize the assignment of fetal sex to dams and test for causal effects of fetal sex on glucoregulatory outcomes using dairy cows as a model. Insulin AUC was not statistically different between groups (ITT p = 0.857, AT p = 0.874), and other outcomes were also not statistically different (p > 0.05). ConclusionWe demonstrated that causal effects of fetal sex on maternal outcomes can be causally tested in dairy cows. Our study did not provide statistical evidence to support an effect of fetal sex on maternal glucose-related outcomes.

Reduced Insulin Clearance Differently Relates to Increased Liver Lipid Content and Worse Glycemic Control in Recent-Onset Type 2 and Type 1 Diabetes.

Diabetes may feature impaired insulin kinetics, which could be aggravated by altered hepatic metabolism and glycemic control. Thus, we examined insulin clearance and its possible determinants in individuals with recent-onset diabetes. Participants of the German Diabetes Study (GDS) with type 1 diabetes (T1D) (n = 306), type 2 diabetes (T2D) (n = 489), or normal glucose tolerance (control [CON]) (n = 167) underwent hyperinsulinemic-euglycemic clamps for assessment of whole-body insulin sensitivity (M value) and insulin clearance (ICCLAMP). Insulin clearance rates were further calculated during intravenous glucose tolerance tests (ICIVGTT) and mixed-meal tests (ICMMT). Hepatocellular lipid content (HCL) was quantified with 1H-MRS. Both T1D and T2D groups had lower ICCLAMP (0.12 ± 0.07 and 0.21 ± 0.06 vs. 0.28 ± 0.14 arbitrary units [a.u.], respectively, all P < 0.05) and ICMMT (0.71 ± 0.35 and 0.99 ± 0.33 vs. 1.20 ± 0.36 a.u., all P < 0.05) than CON. In T1D, ICCLAMP, ICIVGTT, and ICMMT correlated negatively with HbA1c (all P < 0.05). M value correlated positively with ICIVGTT in CON and T2D (r = 0.199 and r = 0.178, P < 0.05) and with ICMMT in CON (r = 0.176, P < 0.05). HCL negatively associated with ICIVGTT and ICMMT in T2D (r = -0.005 and r = -0.037) and CON (r = -0.127 and r = -0.058, all P < 0.05). In line, T2D or CON subjects with steatosis featured lower ICMMT than those without steatosis (both P < 0.05). Insulin clearance is reduced in both T1D and T2D within the first year after diagnosis but correlates negatively with liver lipid content rather in T2D. Moreover, insulin clearance differently associates with glycemic control and insulin sensitivity in each diabetes type, which may suggest specific mechanisms affecting insulin kinetics.

Kinetics of Glucoregulatory Peptide Hormones during Hemodialysis with Cellulose Triacetate and Polysulfone Dialyzers in Patients with Diabetes and End-Stage Kidney Disease.

The mechanisms behind reported decreases in plasma insulin and glucagon during hemodialysis (HD) are not clear. Here, we investigated these mechanisms during HD treatment and the characteristics of insulin and glucagon removal when using two super high-flux membranes. In an experimental study, clearance, adsorption rates, and reduction rates of insulin and glucagon were investigated when using cellulose triacetate (CTA) and polysulfone (PS) membranes in a closed circuit using bovine blood. In a clinical study, 20 diabetes patients with end-stage kidney disease who were stable on HD were randomly selected for two HD sessions with two different membranes. At 1 h after the initiation of HD, insulin and glucagon clearance were measured, and the reduction rates were also investigated. In the experimental study, the PS membrane showed significantly higher clearance, adsorption rates, and reduction rates of insulin and glucagon compared with the CTA membrane. Although glucagon was detected in the ultrafiltration fluids in both membranes, insulin was absent in the PS membrane. In the clinical study, both membranes showed significant reductions in plasma insulin and glucagon at each time point. The PS membrane showed significantly higher insulin clearance and reduction rates compared with the CTA membrane. The two membranes showed no significant difference in glucagon clearance, but the glucagon reduction rate was significantly higher with the PS membrane. Our findings show that HD with the two super high-flux membranes used removes significant amounts of glucoregulatory peptide hormones from plasma in patients with diabetes and end-stage kidney disease, potentially affecting their glucose metabolism.

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

A Short-Term High-Fat Diet Worsens Insulin Sensitivity with Changes in Metabolic Parameters in Non-Obese Japanese Men.

A short-term high-calorie high-fat diet (HCHFD) impairs insulin sensitivity in non-obese South Asian but not Caucasian men; however, the effect of short-term HCHFD on insulin sensitivity in East Asians is unknown. We recruited 21 healthy non-obese Japanese men to evaluate metabolic parameters and gut microbiota before and after 6-day HCHFD consisting of a regular diet plus a 45% energy excess with dairy fat supplementation. We evaluated tissue-specific insulin sensitivity and metabolic clearance rate of insulin (MCRI) using a two-step hyperinsulinemic euglycemic clamp, glucose tolerance using the glucose tolerance test, and measured ectopic fat in muscle and the liver using ¹H-magnetic resonance spectroscopy. The primary outcome of this study was insulin sensitivity measured by the clamp study. The secondary/exploratory outcomes were other metabolic changes. After HCHFD, levels of circulating lipopolysaccharide binding protein (LBP), a marker of endotoxemia, increased by 14%. In addition, intramyocellular lipid levels in the tibialis anterior and soleus and intrahepatic lipid levels increased by 47%, 31%, and 200%, respectively. Insulin sensitivity decreased by 4% in muscle and 8% in liver. However, even with reduced insulin sensitivity, glucose metabolism was maintained by increased serum insulin concentrations due to lower MCRI and higher endogenous insulin secretion during the clamp. Glucose levels during the meal tolerance test were comparable before and after HCHFD. In conclusion, short-term HCHFD impaired insulin sensitivity in the muscle and livers of non-obese Japanese men with increased LBP and ectopic fat accumulation. Elevated insulin levels from modulated insulin secretion and clearance might contribute to the maintenance of normal glucose metabolism during the clamp and meal tolerance test.

Colostrum insulin supplementation to neonatal Holstein bulls affects small intestinal histomorphology, mRNA expression, and enzymatic activity with minor influences on peripheral metabolism

The objectives of this study were to evaluate how varying colostral insulin concentrations influenced small intestinal development and peripheral metabolism in neonatal Holstein bulls. Insulin was supplemented to approximately 5× (70.0 μg/L; n = 16) or 10× (149.7 μg/L; n = 16) the basal colostrum insulin (12.9 μg/L; BI, n = 16) concentration to maintain equivalent macronutrient intake (crude fat: 4.1 ± 0.06%; crude protein: 11.7 ± 0.05%; and lactose: 1.9 ± 0.01%) among treatments. Colostrum was fed at 2, 14, and 26 h postnatal and blood metabolites and insulin concentration were measured at 0, 30, 60, 90, 120, 180, 240, 360, 480, and 600 min postprandial respective to the first and second colostrum meal. At 30 h postnatal, a subset of calves (n = 8/treatment) were killed to excise the gastrointestinal and visceral tissues. Gastrointestinal and visceral gross morphology and dry matter and small intestinal histomorphology, gene expression, and carbohydrase activity were assessed. Insulin supplementation tended to linearly reduce the glucose clearance rate following the first meal, whereas after the second meal, supplementation linearly increased the rate of glucose absorption and nonesterified fatty acid clearance rate, decreased the time to maximum glucose concentrations, and decreased the time to reach minimum nonesterified fatty acid concentrations. Additionally, insulin clearance rate was linearly increased by insulin supplementation following the second colostrum feeding. However, there were no overall differences between treatments in the concentrations of glucose, nonesterified fatty acids, or insulin in plasma or serum. With respect to macroscopic intestinal development, dry rumen tissue mass linearly decreased when insulin was supplemented in colostrum, and supplementation linearly increased duodenal dry tissue density (g dry matter/cm) while tending to increase duodenal dry tissue weight. Increasing the colostrum insulin concentration improved small intestinal histomorphological development in the distal small intestine, as ileal villi height and mucosal-serosal surface area index were increased by supplementing insulin. Lactase enzymatic activity linearly increased in the proximal jejunum while ileal isomaltase activity linearly decreased with insulin supplementation. These data indicate that changes in colostrum insulin concentrations rapidly affect gastrointestinal growth prioritization and carbohydrase activity. The changes in gastrointestinal ontology result in minor changes in postprandial metabolite availability and clearance.

Ageing and Insulin: Inter Alia Diabetes, Obesity and Fitness Concerns

This article argues the essence of insulin sensitivity versus secretion including insulin resistance in the clinical strategy for the treatment, lifestyle changes, prompt interventions and control of diabetes. Progressive decline of glucose tolerance as advanced age occurs has been associated with the pathogenesis of type 2 diabetes due to peripheral insulin resistance and impaired β cell function. In elderly persons, insulin secretion is deranged concomitantly with decreased insulin clearance rate and augmented circulating proinsulin level that ostensibly explicates age-related hyperglycemia. Insulin is associated with numerous pathophysiological processes exhibited during brain function in learning and memory, as well as the regulation of ageing, metabolic syndrome, obesity, diabetes and cardiovascular diseases in Man. Elevated chronic peripheral insulin, decreased insulin action and brain insulin contents are pathognomonic of the insulin resistance syndrome. All these are associated through specific mechanisms in the pathophysiology of ageing and insulin in concert with risk factors and the concomitant complications. Ostensibly, progressive excess insulin induces synchronous elevated levels of oxidative stress and inflammatory impacts which exacerbate or are exacerbated by advancing age, culminating as inimical consequences to healthy lifestyles, longevity or extended lifespan. Therapeutics and other healthcare measures may be beneficial in order to prevent, mitigate or amend insulin aberrations in the elderly and during the ageing process. The mainstay in managing an elderly patient with perturbed insulin action, is control of therapeutic application, as it can reverse acute terminal states. Treatment necessitates stringent and thorough expertise, knowledge and skills for optimum provision and effective cerebral, cardiovascular and skeletal protection for a healthier lifespan and longevity. This article will be of immense contribution in the understanding of the prevention, control and treatment of insulin resistance, metabolic syndrome, diabetes, obesity, cardiovascular and neurological disorders during ageing.

PSUN299 GLP-1 Contribution to Insulin Secretory Response to Protein Ingestion and Insulin Kinetics Following Gastric Bypass and Sleeve Gastrectomy

Abstract Rapid passage of ingested nutrients to the gut after Roux-en-Y gastric bypass (GB) and sleeve gastrectomy (SG) results in hyperinsulinemia after glucose ingestion, in part due to an enhanced glucagon-like peptide-1 (GLP-1)-induced insulin secretory response (ISR) and reduced metabolic clearance rate of insulin (MCRI). The effect of endogenous GLP-1 on insulin kinetics is unknown, and so is GLP-1 contribution to insulin secretory response to non-glucose nutrient ingestion. In non-surgical subjects, protein ingestion enhances insulin secretion and reduces MCRI. We hypothesized that protein ingestion enhances GLP-1-induced ISR and alters MCRI in proportion to changes in nutrient influx after GB and SG. To test this hypothesis ISR, β-cell sensitivity to glucose (BGS), MCRI, and oral glucose insulin sensitivity (OGIS) were measured on 3 days during 50 g glucose ingestion as well as 50 g protein ingestion with and without GLP-1R antagonist, exendin (9-39) [Ex-9] infusion. Ten GB-treated subjects, 9 SG-treated, and 7 non-operated controls (CN) were enrolled. The 3 non-diabetic groups were matched for age, BMI, fat-free mass, HbA1c; surgical groups were matched for weight loss and time post-surgery. Fasting glucose, insulin, and ISR were similar among the 3 groups and among the 3 studies but fasting MCRI was greater in surgical groups than CN (p&amp;lt;0.05). Compared to glucose, protein ingestion led to larger BGS in 3 groups despite smaller overall ISR response (AUCISR3h) (p&amp;lt;0.05). Blocking GLP-1R during protein ingestion decreased AUCISR3h only in surgical subjects (p&amp;lt;0.05 for interaction), whereas BGS was reduced similarly in 3 groups during Ex-9 infusion (p&amp;lt;0.05). OGIS was smaller during protein than glucose ingestion in 3 groups (p&amp;lt;0.05). GLP-1R blockade did not affect insulin sensitivity. Following nutrient ingestion in parallel with increase in insulin secretion MCRI was reduced to nadir values at 40 minutes, but then gradually increased approaching premeal values at different pace among surgical and non-surgical subjects (p&amp;lt;0.05). The slope of MCRI: Insulin (0-40 min) was smaller after protein ingestion than glucose, and after protein with Ex-9 infusion than without in 3 groups (p&amp;lt;0.05). Blocking GLP-1R had no effect on MCRI values in the latter phase of protein ingestion when insulin secretion reduced approaching premeal values. There was no association between parameters of insulin sensitivity and insulin clearance during glucose or protein ingestion. Our findings indicate that the regulation of insulin secretion and clearance during protein ingestion is altered after GB and SG. Further, endogenous GLP-1 contribution to insulin secretory response to protein ingestion after GB and SG is enhanced, but GLP-1 effect on insulin kinetics is trivial. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

Understanding the In vivo, pathogenesis, evaluation and management of ageing and insulin

This article presents the essence of insulin sensitivity, secretion and resistance in the treatment, lifestyle modifications, interventions and control of diabetes, obesity and related disorders . Progressive decline of glucose tolerance with advanced age is associated with the pathogenesis of type 2 diabetes due to peripheral insulin resistance and impaired β cell function. In elderly persons, insulin secretion is impaired with decreased insulin clearance rate and increased circulating proinsulin concentration that suggests age-related hyperglycaemia. Insulin is associated with numerous pathophysiologic mechanisms during brain functionality, learning and memory, as much as in the regulation of ageing, metabolic syndrome, obesity, diabetes and cardiovascular diseases in Man. Elevated chronic peripheral insulin, decreased insulin action and brain insulin levels are pathognomonic of the insulin resistance syndrome. These are entirely associated by means of defined mechanisms in the pathophysiology of ageing and insulin in concert with risk factors and concomitant complications. Suggestively, progressive excess insulin potentiates synchronous elevated levels of oxidative stress and inflammatory effects which exacerbate or are aggravated by advancing age, leading to inimical consequences of healthy lifestyles, longevity or extended lifespan. Therapeutics and other healthcare measures may be beneficial to prevent, mitigate or amend insulin aberrations in the elderly and during the ageing process. The mainstay in the management of the elderly patient with perturbed insulin function is control of therapeutic application, as it is capable of reverting acute terminal conditions. Treatment necessitates stringent and ardent expertise, knowledge and skills for optimum provision and effective cerebral, cardiovascular and skeletal protection for a healthier lifespan and longevity. This article contributes to the understanding of the prevention, treatment and control of insulin resistance, metabolic syndrome, diabetes, obesity, cardiovascular and neurological disorders during ageing.

Berberine supplementation modulates the somatotropic axis and ameliorates glucose tolerance in dairy goats during late gestation and early lactation

BackgroundPregnancy, parturition, and the onset of lactation represent an enormous physiological and hormonal challenge to the homeostasis of dairy animals, being a risk for their health and reproduction. Thus, as a part of the homothetic changes in preparturition period, goats undergo a period of IR as well as uncoupled GH/IGF-1 axis. The objective for this study was to determine the effect of berberine (BBR) during the peripartal period on hormonal alteration and somatotropic axis in dairy goats as well as glucose and insulin kinetics during an intravenous glucose tolerance test (IVGTT). At 21 days before the expected kidding date, 24 primiparous Saanen goats were assigned randomly to 4 dietary treatments. Goats were fed a basal diet from wk. 3 antepartum (AP) until wk. 3 postpartum (PP) supplemented with 0 (CTRL), 1 (BBR1), 2 (BBR2), and 4 (BBR4) g/d BBR. Blood samples were collected on days − 21, − 14, − 7, 0, 7, 14, and 21 relative to the expected kidding date. An IVGTT was also performed on day 22 PP.ResultsCompared with CTRL, supplementation with either BBR2 or BBR4 increased DMI at kidding day and PP, as well as body conditional score (BCS) and milk production (p ≤ 0.05). On d 7 and 14 PP plasma glucose was higher in BBR2- and BBR4-treated than in CTRL. The glucagon concentration was not affected by BBR during the experimental period. However, supplemental BBR indicated a tendency to decrease in cortisol concentration on days 7 (p = 0.093) and 14 (p = 0.100) PP. Lower plasma GH was observed in BBR than in non-BBR goats (p ≤ 0.05). Plasma IGF-1 concentration was enhanced in both BBR2 and BBR4 at kidding and day 7 PP (p ≤ 0.05). During the IVGTT, glucose area under the curve (AUC), clearance rate (CR), T1/2, and Tbasal was lower (p ≤ 0.05) in both BBR2 and BBR4 goats as compared with CTRL. Likewise, the insulin CR was higher (p ≤ 0.05) in goats receiving either BBR2 or BBR4 which was accompanied by a lower insulin T1/2 and AUC.ConclusionsAltogether, our results indicated an improved glucose and insulin status along with the modulation of the somatotropic axis and glucose and insulin response to IVGTT in dairy goats supplemented with 2 and 4 g/d BBR.

Effect of excessive gestational weight gain on insulin sensitivity and insulin kinetics in women with overweight/obesity.

Obesity increases the risk for pregnancy complications and maternal hyperglycemia. The Institute of Medicine developed guidelines for gestational weight gain (GWG) targets for women with overweight/obesity, but it is unclear whether exceeding these targets has adverse effects on maternal glucose metabolism. Insulin sensitivity (assessed using the Matsuda Insulin Sensitivity Index), β-cell function (assessed as insulin secretion rate in relation to plasma glucose), and plasma insulin clearance rate were evaluated using a frequently sampled oral glucose tolerance test at 15 and 35 weeks of gestation in 184 socioeconomically disadvantaged African American women with overweight/obesity. Insulin sensitivity decreased, whereas β-cell function and insulin clearance increased from 15 to 35 weeks of gestation in the entire group. Compared with women who achieved the recommended GWG, excessive GWG was associated with a greater decrease in insulin sensitivity between 15 and 35 weeks. β-cell function and plasma insulin clearance were not affected by excessive GWG. These data demonstrate that gaining more weight during pregnancy than recommended by the Institute of Medicine is associated with functional effects on glucose metabolism.

Impaired pancreatic beta-cell function after a single dose of oral iron: A before-and-after (pre-post) study.

Although in vitro and animal studies have shown that iron loading in pancreatic beta cells impairs insulin secretion, no human studies have documented the acute effects of oral iron on beta-cell insulin secretory capacity. In the present study, we determined beta-cell insulin secretory capacity at baseline and after a single oral dose of iron (ferrous sulphate, 120 mg elemental iron) in healthy male individuals. Fifteen healthy male volunteers underwent an oral glucose tolerance test (OGTT) to document baseline glucose tolerance and insulin secretion kinetics (baseline OGTT). One week later, the same subjects underwent a second OGTT, 2 h after an oral dose of ferrous sulphate (120 mg of elemental iron) (post-iron OGTT). Changes in disposition index, insulin secretion kinetics, glucose tolerance, insulin resistance, insulin clearance and iron-related parameters in serum were determined. Compared to baseline OGTT, the areas under the curve (AUC) for serum iron and transferrin saturation increased by 125% and 118%, respectively, in the post-iron OGTT. The disposition index decreased by 20% (p = 0.009) and the AUC for glucose concentrations increased by 5.7% (p < 0.001) during the post-iron OGTT. The insulin secretion rate was marginally lower during the first hour (-3.5%, p = 0.63), but became significantly higher during the second hour (22%, p = 0.005) of the post-iron OGTT. Insulin resistance and insulin clearance rate were not affected by iron intake. The decrease in disposition index and glucose tolerance observed after the oral dose of iron points to an acute iron-induced impairment in pancreatic beta-cell insulin secretory capacity.

Altered Insulin Clearance after Gastric Bypass and Sleeve Gastrectomy in the Fasting and Prandial Conditions.

Background: The liver has the capacity to regulate glucose metabolism by altering the insulin clearance rate (ICR). The decreased fasting insulin concentrations and enhanced prandial hyperinsulinemia after Roux-en-Y gastric-bypass (GB) surgery and sleeve gastrectomy (SG) are well documented. Here, we investigated the effect of GB or SG on insulin kinetics in the fasting and fed states. Method: ICR was measured (i) during a mixed-meal test (MMT) in obese non-diabetic GB (n = 9) and SG (n = 7) subjects and (ii) during a MMT combined with a hyperinsulinemic hypoglycemic clamp in the same GB and SG subjects. Five BMI-matched and non-diabetic subjects served as age-matched non-operated controls (CN). Results: The enhanced ICR during the fasting state after GB and SC compared with CN (p < 0.05) was mainly attributed to augmented hepatic insulin clearance rather than non-liver organs. The dose-response slope of the total insulin extraction rate (InsExt) of exogenous insulin per circulatory insulin value was greater in the GB and SG subjects than in the CN subjects, despite the similar peripheral insulin sensitivity among the three groups. Compared to the SG or the CN subjects, the GB subjects had greater prandial insulin secretion (ISR), independent of glycemic levels. The larger post-meal ISR following GB compared with SG was associated with a greater InsExt until it reached a plateau, leading to a similar reduction in meal-induced ICR among the GB and SG subjects. Conclusions: GB and SG alter ICR in the presence or absence of meal stimulus. Further, altered ICR after bariatric surgery results from changes in hepatic insulin clearance and not from a change in peripheral insulin sensitivity.

1298-P: Metabolic Clearance of Insulin Is Altered after Gastric Bypass and Sleeve Gastrectomy

Roux-en-Y gastric bypass (GB) surgery and sleeve gastrectomy (SG) improve glucose tolerance, in part, by enhancing prandial insulin levels. Post-meal hyperinsulinemia after GB is caused by larger insulin secretion and lower metabolic clearance rate of insulin (MCRI) . Reduced prandial MCRI after GB is exaggerated in those with post-GB complication of hypoglycemia, suggesting that altered MCRI is a pathogenic factor. We investigated the role of GB or SG on insulin kinetics in fasting and fed states. The MCRI were measured during a mixed meal text (MMT) in 9 GB and 7 SG subjects: and during MMT combined with hyperinsulinemic hypoglycemic clamp in 9 GB, 7 SG, and 5 CN. Three groups were matched for age and BMI and surgical groups for time and weight loss since surgery; none had diabetes or liver disease. Fasting MCRI was greater in GB and SC than CN (p&amp;lt;0.05) . Meal ingestion diminished MCRI to a larger extent in GB subjects compared to SG reaching nadir values in 20-50 min (relative reduction in GB vs. SG: 82±3% vs. 74±3%, p&amp;lt;0.05) . The relative postprandial reduction in MCRI was inversely associated with the glycemic excursion and insulin response. During the clamp hepatic insulin clearance was larger in GB and SG compared to CN (p&amp;lt;0.05) . There was no association between hepatic insulin clearance and peripheral insulin sensitivity (M/I) . Induced hyperinsulinemia approximating 300 µU/ml reduced MCRI in 3 groups despite a larger M/I in surgical subjects. Meal ingestion during hyperinsulinemic hypoglycemia clamp raised MCRI in 3 groups (p&amp;lt;0.05) returning to pre-meal values in an hour. These findings demonstrate that the differences in basal MCRI among GB, SG and CN are mainly attributed to variations in insulin clearance in the liver and independent on peripheral insulin sensitivity. Further, prandial reduction in MCRI is greater after GB than SG in proportion to the rates of nutrient influx.; the effect of nutrient ingestion on insulin kinetics is altered during hyperinsulinemic hypoglycemia. Disclosure M.S.Rayas: None. R.A.Defronzo: Advisory Panel; AstraZeneca, Boehringer Ingelheim International GmbH, Intarcia Therapeutics, Inc., Novo Nordisk, Research Support; AstraZeneca, Boehringer Ingelheim International GmbH, Merck &amp; Co., Inc., Speaker's Bureau; AstraZeneca. A.Gastaldelli: Advisory Panel; Boehringer Ingelheim International GmbH, Novo Nordisk, Consultant; Boehringer Ingelheim International GmbH, Inventiva Pharma, Other Relationship; Eli Lilly and Company, Gilead Sciences, Inc., Pfizer Inc., Speaker's Bureau; Novo Nordisk. M.Salehi: None. Funding National Institute of Diabetes, Digestive, and Kidney Diseases (DK105379)

Exploring dynamical properties of a Type 1 diabetes model using sensitivity approaches

The high global prevalence of diabetes, and the extortionate costs imposed on healthcare providers necessitate further research to understand different perspectives of the disease. In this paper, a mathematical model for Type 1 diabetes glucose homeostasis system was developed to better understand disease pathways. Type 1 diabetes pathological state is shown to be globally asymptomatically stable when the model threshold T0<1, and exchanges stability with the managed diabetes equilibrium state i.e. globally asymptotically stable when T0>1. Sensitivity analysis was conducted using partial rank correlation coefficient (PRCC) and Sobol′ method to determine influential model parameters. Sensitivity analysis was performed at different significant time points relevant to diabetes dynamics. Our sensitivity analysis was focused on the model parameters for glucose homeostasis system, at 3 to 4 hour time interval, when the system returns to homeostasis after food uptake. PRCC and Sobol′ method showed that insulin clearance and absorption rates were influential parameters in determining the model response variables at all time points at which sensitivity analysis was performed. PRCC method also showed the model subcutaneous bolus injection term to be important, thus identified all parameters in T0 as influential in determining diabetes model dynamics. Sobol′ method complemented the sensitivity analysis by identifying relationships between parameters. Sensitivity analysis methods concurred in identifying some of the influential parameters and demonstrated that parameters which are influential remain so at every time point. The concurrence of both PRCC and Sobol′ methods in identifying influential parameters (in T0) and their dynamic relationships highlight the importance of statistical and mathematical analytic approaches in understanding the processes modeled by the parameters in the glucose homeostasis system.

Potential Identification of Type 2 Diabetes with Elevated Insulin Clearance

BackgroundDecreased blood insulin concentrations resulting from reduced pancreatic β-cell insulin secretion and elevated insulin clearance (IC) could be involved in impaired glucose metabolism in diabetes. Recently, we reported a patient with type 2 diabetes mellitus (T2DM) who had decreased blood insulin concentrations and elevated IC.MethodsFor this study, we recruited patients with newly diagnosed, treatment-naïve T2DM and measured the metabolic clearance rate of insulin (MCRI) determined by a hyperinsulinemic-euglycemic clamp examination. We defined elevated IC as an MCRI of more than 700 ml/min/m2. Using this tentative cutoff, we identified patients with T2DM with elevated IC and investigated their clinical characteristics.ResultsWe enrolled 101 patients in this study; 78.2% were men. Patients had a mean age of 54.1 years, a median body-mass index (BMI) of 25.1 kg/m2 (interquartile range [IQR], 22.9 to 28.4 kg/m2), a median hemoglobin A1c of 10.0% (IQR, 8.0 to 12.3%), and a median MCRI of 655 ml/min/m2 (IQR, 562 to 810 ml/min/m2). Our case definition for elevated IC was met by 44 patients whose median MCRI was 842 ml/min/m2 (IQR, 747 to 975 ml/min/m2) compared with those without elevated IC (570 ml/min/m2; IQR, 500 to 628 ml/min/m2). On the basis of this division, fasting blood glucose and insulin levels were 178 mg/dl (IQR, 140 to 218 mg/dl) and 4.2 mU/l (IQR, 2.7 to 5.5 mU/l), respectively, in patients with elevated IC compared with 146 mg/dl (IQR, 128 to 188 mg/dl) and 9.6 mU/l (IQR, 6.6 to 14.9 mU/l), respectively, in patients without elevated IC. The BMI of patients with elevated IC was 22.9 kg/m2 (IQR, 20.7 to 24.2 kg/m2) compared with 27.3 kg/m2 (IQR, 25.2 to 29.4 kg/m2) in patients who did not have elevated IC. There were no clinically significant differences in renal or hepatic function test results.ConclusionsOur data suggest that there is a group of patients with T2DM with elevated IC, and that they are nonobese and have decreased blood insulin concentrations. If confirmed, this novel form of T2DM could affect the treatment of such patients. (UMIN Clinical Trials Registry number, UMIN000032014.)

Can Exercise Training Alter Human Skeletal Muscle DNA Methylation?

Skeletal muscle is highly plastic and dynamically regulated by the body’s physical demands. This study aimed to determine the plasticity of skeletal muscle DNA methylation in response to 8 weeks of supervised exercise training in volunteers with a range of insulin sensitivities. We studied 13 sedentary participants and performed euglycemic hyperinsulinemic clamps with basal vastus lateralis muscle biopsies and peak aerobic activity (VO2 peak) tests before and after training. We extracted DNA from the muscle biopsies and performed global methylation using Illumina’s Methylation EPIC 850K BeadChip. Training significantly increased peak aerobic capacity and insulin-stimulated glucose disposal. Fasting serum insulin and insulin levels during the steady state of the clamp were significantly lower post-training. Insulin clearance rates during the clamp increased following the training. We identified 13 increased and 90 decreased differentially methylated cytosines (DMCs) in response to 8 weeks of training. Of the 13 increased DMCs, 2 were within the following genes, FSTL3, and RP11-624M8.1. Of the 90 decreased DMCs, 9 were within the genes CNGA1, FCGR2A, KIF21A, MEIS1, NT5DC1, OR4D1, PRPF4B, SLC26A7, and ZNF280C. Moreover, pathway analysis showed an enrichment in metabolic and actin-cytoskeleton pathways for the decreased DMCs, and for the increased DMCs, an enrichment in signal-dependent regulation of myogenesis, NOTCH2 activation and transmission, and SMAD2/3: SMAD4 transcriptional activity pathways. Our findings showed that 8 weeks of exercise training alters skeletal muscle DNA methylation of specific genes and pathways in people with varying degrees of insulin sensitivity.

Is calorie restriction beneficial for normal-weight individuals? A narrative review of the effects of weight loss in the presence and absence of obesity.

Calorie restriction regimens are popular for their purported health-promoting effects. However, it is unclear whether chronic reduction in energy intake and subsequent weight loss have beneficial effects in the absence of obesity. To this end, the results of studies that examined the effects of the same diet-induced weight loss in individuals with and without obesity were reviewed. The contribution of lean mass to the total amount of weight lost is greater in participants without obesity than in those with obesity, but the reductions in resting, nonresting, and total energy expenditure are of similar magnitude. Both in the presence as well as in the absence of obesity, weight loss decreases visceral adipose tissue and liver fat, increases insulin sensitivity in skeletal muscle (insulin-mediated whole-body glucose disposal rate) and in adipose tissue (meal-induced or insulin-induced suppression of plasma free fatty acid concentration), and augments insulin clearance rate, without affecting pancreatic insulin secretion. These effects are of similar magnitude in participants with and without obesity and result in reductions in fasting plasma glucose and insulin concentrations. These data suggest that the same degree of calorie restriction and the same amount of weight loss have multiple beneficial effects on health outcomes in individuals without obesity, similar to those observed in individuals with obesity.

Examining Type 1 Diabetes Mathematical Models Using Experimental Data

Type 1 diabetes requires treatment with insulin injections and monitoring glucose levels in affected individuals. We explored the utility of two mathematical models in predicting glucose concentration levels in type 1 diabetic mice and determined disease pathways. We adapted two mathematical models, one with -cells and the other with no -cell component to determine their capability in predicting glucose concentration and determine type 1 diabetes pathways using published glucose concentration data for four groups of experimental mice. The groups of mice were numbered Mice Group 1–4, depending on the diabetes severity of each group, with severity increasing from group 1–4. A Markov Chain Monte Carlo method based on a Bayesian framework was used to fit the model to determine the best model structure. Akaike information criteria (AIC) and Bayesian information criteria (BIC) approaches were used to assess the best model structure for type 1 diabetes. In fitting the model with no -cells to glucose level data, we varied insulin absorption rate and insulin clearance rate. However, the model with -cells required more parameters to match the data and we fitted the -cell glucose tolerance factor, whole body insulin clearance rate, glucose production rate, and glucose clearance rate. Fitting the models to the blood glucose concentration level gave the least difference in AIC of , and a difference in BIC of for Mice Group 4. The estimated AIC and BIC values were highest for Mice Group 1 than all other mice groups. The models gave substantial differences in AIC and BIC values for Mice Groups 1–3 ranging from to . Our results suggest that the model without -cells provides a more suitable structure for modelling type 1 diabetes and predicting blood glucose concentration for hypoglycaemic episodes.