Maximum Insulin Concentration Research Articles

P300 or CBP are required for calorie restriction-mediated enhancement of skeletal muscle insulin sensitivity

A calorie-restricted diet robustly improves skeletal muscle insulin sensitivity and is a cornerstone lifestyle intervention for preventing and treating clinical hyperglycemia. While studies demonstrate that insulin-stimulated activation of phosphatidylinositol 3-kinase (PI3K) and RAC-beta serine/threonine-protein kinase (AKT2) are fundamental to enhanced muscle insulin sensitivity after calorie restriction (CR), the downstream signaling steps remain to be fully elucidated. We have previously demonstrated that the lysine acetyltransferases, E1A binding protein (p300) or cAMP response element binding protein binding protein (CBP) are required for insulin-stimulated glucose uptake by skeletal muscle, at both sub-maximal and maximal concentrations of insulin. Moreover, p300/CBP are phosphorylated by AKT, which increases their acetyltransferase activity. Considering these findings together, the objective of this study was to determine whether p300 or CBP are required for the ability of CR to enhance skeletal muscle insulin sensitivity. We hypothesized that combined inhibition of p300 and CBP acetyltransferase activity would prevent CR-induced enhancement of skeletal muscle insulin sensitivity. To address this objective, 8-week-old male C57BL/6NJ mice were either fed ad libitum (AL; n=16) or were fed a CR diet (60% of AL intake; n=16) diet for 20 days. Then, an ex vivo [3H]-2-deoxyglucose (2DOG) approach was used to assess basal and insulin-stimulated (60μU/mL [0.36nM]) 2DOG uptake in paired extensor digitorum longus (EDL) and soleus from fasted (4 h) mice. To define the role of p300/CBP acetyltransferase activity, paired muscles from AL- or CR-fed mice were pre-incubated for 60 minutes with either DMSO (experimental control; n=8/dietary group [AL-DMSO, CR-DMSO]) or the p300/CBP acetyltransferase activity inhibitor, ip300w (25mM; n=8/dietary group [AL-ip300w, CR-ip300w]). As expected, insulin-stimulated 2DOG uptake (i.e. Insulin 2DOG minus basal 2DOG) in DMSO incubated muscles was ~2.3-fold and ~3.3-fold higher in the soleus and EDL, respectively, from CR- vs. AL-fed mice. Remarkably, ip300w not only blocked insulin-stimulated 2DOG uptake in AL-fed mice, but it also abrogated the insulin-sensitizing effects of CR on muscle insulin sensitivity. To further define the importance of p300 and CBP to CR-induced enhancement of skeletal muscle insulin sensitivity, we studied mice with tamoxifen-inducible and skeletal muscle-specific knockout of CBP and heterozygous (HZ) loss of p300 (referred to as, i-mCKO/PHZ) or knockout of p300 and HZ loss of CBP (referred to as, i-mPKO/CHZ). In these mice, the AL diet or 20 days of CR was initiated 3 weeks after ~10 week-old mice were dosed with tamoxifen (5 consecutive days, 2 mg/day); Cre recombinase-negative littermates, who were also dosed with tamoxifen, were the experimental controls (referred to as wildtype [WT]). Interestingly, oral glucose tolerance and EDL insulin sensitivity were comparably enhanced by CR in WT and both i-mCKO/PHZ and i-mPKO/CHZ mice, thus suggesting that just one allele of p300 or CBP is suffcient for CR to enhance skeletal muscle insulin sensitivity. Taken together, these results demonstrate that p300 or CBP are essential for the ability of calorie restriction to enhance skeletal muscle insulin sensitivity. This work was supported by a grant from the National Institutes of Health (R56 DK1311211), and the Dr. Maryam Ahmadian Memorial Summer Fellowship Program (L.M.L.) and the UC San Diego Medical Scientist Training Program (L.S.F.). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Pharmacokinetic and pharmacodynamic bioequivalence of Gan & Lee insulin analogues aspart (rapilin®), lispro (prandilin®) and glargine (basalin®) with EU- und US-sourced reference insulins.

For the successful approval and clinical prescription of insulin biosimilars, it is essential to show pharmacokinetic (PK) and pharmacodynamic (PD) bioequivalence to the respective reference products sourced from the European Union and the United States. Three phase 1, randomized, double-blind, three-period crossover trials compared single doses of the proposed biosimilar insulin analogues aspart (GL-Asp, n = 36), lispro (GL-Lis, n = 38) and glargine (GL-Gla, n = 113), all manufactured by Gan & Lee pharmaceuticals, to the respective EU- and US-reference products in healthy male participants (GL-Asp and GL-Lis) or people with type 1 diabetes (GL-Gla). Study participants received 0.2 U/kg (aspart and lispro) or 0.5 U/kg (glargine) of each treatment under automated euglycaemic clamp conditions. The clamp duration was 12 h (aspart and lispro) or 30 h (glargine). Primary PK endpoints were the total area under the PK curves (AUCins.total ) and maximum insulin concentrations (Cins.max ). Primary PD endpoints were the total area under the glucose infusion rate curve (AUCGIR.total ) and maximum glucose infusion rate (GIRmax ). Bioequivalence to both EU- and US-reference products were shown for all three GL insulins. Least squares mean ratios for the primary PK/PD endpoints were close to 100%, and both 90% and 95% confidence intervals were within 80%-125% in all three studies. There were no noticeable differences in the safety profiles between test and reference insulins, and no serious adverse events were reported for the GL insulins. GL-Asp, GL-Lis and GL-Gla are bioequivalent to their EU- and US-reference products.

Supplementation of an organic mineral source modulated metabolic profile, insulin sensitivity, and oxidative stress in dairy calves with different birth body weights

The present study was conducted to investigate the effects of partial replacement of inorganic minerals (IM) with advanced chelated minerals (ACMS) in the starter diets of calves of different birth body weights (BBW) on metabolic indices and glucose tolerance test. Fifty-two Holstein calves were assigned to one of 4 treatments in a 2 × 2 factorial arrangement with two mineral sources (IM or ACMS) and two BBW (low or normal birth weight; LBW or NBW). Calves were weaned on day 56 and remained in the study until day 71 of the study. Blood samples for blood metabolite analysis were collected from the jugular vein on days 30, 60, and 70 of the study, and for hematology on days 36, 56, and 70. The results showed that the interaction of starter mineral sources (MS) and BBW affected the overall plasma concentration of β-hydroxybutyrate (BHB), with the highest value being obtained during treatment with LBW-ACMS. In addition, an interaction between MS and BBW was observed in plasma insulin concentrations, with LBW-IM calves having the lowest concentrations compared to the other treatments. Plasma albumin concentrations were lower in LBW calves than in NBW calves. In addition, NBW calves had greater plasma concentrations of glucose (day 60), insulin (day 30), BHB (day 30), and malondialdehyde (MDA; day 60 and the overall period) than LBW calves, while total antioxidant capacity (TAC) tended to reverse at day 70. The ACMS starter increased plasma glucose concentration at day 30 and tended to increase plasma BHB concentration in the overall period. In addition, plasma MDA concentrations were lower in calves receiving ACMS than in calves receiving IM during the overall period. NBW calves tended to have more eosinophils (day 70), basophils (day 36), and erythrocytes (RBC, day 56, and the overall period) in plasma than LBW calves. Regardless of BBW, feeding ACMS starter increased white blood cells (WBC), neutrophils, and eosinophils at day 70 and also tended to increase neutrophils during the overall period compared with the IM groups. Red blood cell concentrations were greater in calves fed ACMS than in calves fed IM during the overall period. Glucose tolerance test showed that basal glucose concentration and clearance rate (CR) of glucose tended to be lower and higher, respectively, in calves fed ACMS than in calves fed IM. ACMS supplementation increased basal concentrations and also tended to increase maximum insulin concentrations compared with IM supplementation. In addition, calves receiving ACMS starter had greater plasma insulin area under the curve (AUC) and CR compared with calves receiving IM. Feeding ACMS tended to increase the ratio CR of insulin to CR of glucose and increased the AUC of insulin to AUC of glucose compared with feeding IM. Overall, feeding ACMS resulted in a decrease in plasma MDA concentration and an increase in neutrophil concentration, suggesting that ACMS may improve immune function in these calves. A potential insulinotropic effect was noted with ACMS feeding, which was accompanied by an improvement in glucose control rate. This is likely due to higher bioavailability of chelated minerals such as Zn and should be further investigated.

Bioequivalence and immunogenicity of insulin LisPro biosimilar compared to reference drug

Introduction. Insulin therapy is the only treatment for type 1 DM and one of the options for intensifying the treatment for type 2 DM. The production of own insulin biosimilars will increase patients access to the providing drugs and can potentially reduce medical costs on healthcare for government. Aim. Compare the equivalence of pharmacokinetics (PK) and pharmacodynamics (PD), safety, efficacy, and immunogenicity between insulin biosimilar RinLis®, 100 IU/ml (LLC GEROPHARM, Russia) to original Humalog®, 100 IU/ml (Lilly France, France). Materials and methods. The clinical trial was conducted in two phases. Phase I – randomized double-blind, two-arm crossover study of PK and PD using hyperinsulinemic euglycemic clamp (HEC) method in 28 healthy volunteers (NCT03604575). During HEC regular blood sampling was performed to assess glucose and insulin concentrations. The glucose infusion rate (GIR) was adjusted based on glycemia measurement. These data were used to calculate the PD parameters: the total area under the GIR-time curve (AUCGIR) and the maximum GIR over the observation period (GIRmax); PK parameters: the total area under the concentration – time curve (AUCins.) and the maximum insulin concentration over the HEC (Сins. max). Phase II – randomized multicenter open-label comparative study in parallel groups with an assessment the frequency of an immune response after 26 weeks of therapy (NCT04023344). The comparability of the studied drugs was considered proven if 90% confidence intervals (CI) for the ratio of geometric means of FC and PD were in the range of 80–125%. Results. In the course of the study, it was revealed that RinLiz® and Humalog® insulin had comparable PK and PD profiles. The ratio of the geometric mean values of the AUCGIR and GIRmax were in the range of 80–125% and amounted to 106 [95–118] % and 108 [97–121] %, respectively. The equivalence also was confirmed by the ratio of the geometric mean values of the AUCins. and Сins. max, which amounted to 91 [86–97] % and 94 [91–97] %. In the second phase of the study after 26 weeks of therapy the frequency of immune response between two groups did not differ. Conclusion. The obtained data have demonstrated the bioequivalence and immunogenicity of RinLiz® insulin to the original Humalog® in terms of PK, PD and safety parameters.

Adult-onset nesidioblastosis: a challenging diagnosis revealed by glucagon-like-peptide-1 receptor imaging

A 52-year-old female presented with recurrent episodes of fasting or post-absorptive hypoglycemia. A 72-h fasting test confirmed endogenous hyperinsulinemia. Conventional imaging was unremarkable. Selective pancreatic arterial calcium stimulation and hepatic venous sampling showed a maximum calcium-stimulated insulin concentration from several pancreatic areas, mainly the proximal splenic artery and the proximal gastroduodenal artery, suggesting the presence of one or more occult insulinoma(s) in the region of the pancreatic body. 68Ga-DOTA-exendin-4 PET/CT showed however generalized increased uptake in the pancreas and a diagnosis of nesidioblastosis was therefore suspected. The patient has been since successfully treated with dietetic measures and diazoxide. Treatment efficacy was confirmed by a flash glucose monitoring system with a follow-up of 7 months. Adult nesidioblastosis is a rare cause of endogenous hyperinsulinemic hypoglycemia. The distinction between insulinoma and nesidioblastosis is essential since the therapeutic strategies are different. 68Ga-DOTA-exendin-4 PET/CT emerges as a new noninvasive diagnostic tool for the localization of an endogenous source of hyperinsulinemic hypoglycemia. Medical management with dietetic measures and diazoxide need to be considered as a valuable option to treat patients with adult nesidioblastosis. Flash glucose monitoring system is helpful for the evaluation of treatment efficacy.

Pharmacokinetic and pharmacodynamic equivalence of Biocon's biosimilar Insulin 70/30 with US-licensed HUMULIN® 70/30 formulation in healthy subjects: Results from the RHINE-3 (Recombinant Human INsulin Equivalence-3) study.

AimTo establish the pharmacokinetic (PK) and pharmacodynamic (PD) equivalence of proposed biosimilar insulin 70/30 (Biocon's Insulin‐70/30) and HUMULIN® 70/30 (HUMULIN‐70/30; Eli Lilly and Company, IN).Materials and MethodsIn this phase 1, automated euglycaemic glucose clamp study, 78 healthy subjects were randomized (1:1) to receive a single dose of 0.4 IU/kg of Biocon's Insulin‐70/30 and HUMULIN‐70/30. Plasma insulin concentrations and glucose infusion rates (GIRs) were assessed over 24 hours. Primary PK endpoints were area under the insulin concentration‐time curve from 0 to 24 hours ‐ AUCins.0−24h ‐ and maximum insulin concentration ‐ Cins.max. Primary PD endpoints were area under the GIR time curve from 0 to 24 hours ‐ AUCGIR.0−24h ‐ and maximum GIR ‐ GIRmax.ResultsEquivalence was shown between Biocon's Insulin‐70/30 and HUMULIN‐70/30 for the primary PK/PD endpoints. The 90% confidence intervals of the treatment ratios were entirely within the acceptance range of 80.00%‐125.00%. The secondary PK/PD profiles were also comparable. There were no clinically relevant differences in the safety profiles of the two treatments and no serious adverse events were reported.ConclusionPK/PD equivalence was demonstrated between Biocon's Insulin‐70/30 and HUMULIN‐70/30 in healthy subjects. Treatment with Biocon's Insulin‐70/30 and HUMULIN‐70/30 was well tolerated.

Pharmacokinetic and pharmacodynamic equivalence of Biocon's biosimilar Insulin-R with the US-licensed Humulin® R formulation in healthy subjects: Results from the RHINE-1 (Recombinant Human INsulin Equivalence-1) study.

AimTo establish equivalence in the pharmacokinetic (PK) and pharmacodynamic (PD) endpoints between proposed biosimilar Insulin‐R (Biocon's Insulin‐R) and Humulin® R using the euglycaemic clamp technique in healthy subjects.Materials and MethodsIn this phase‐1 automated euglycaemic glucose clamp study, 42 healthy subjects were randomized (1:1) to receive a single dose of 0.3 IU/kg of Biocon's Insulin‐R and Humulin‐R. Plasma insulin concentrations and glucose infusion rates (GIRs) were assessed over 12 hours. Primary PK endpoints were area under the insulin concentration‐time curve from 0 to 12 hours (AUCins.0‐12h) and maximum insulin concentration (Cins.max). Primary PD endpoints were area under the GIR time curve from 0 to 12 hours (AUCGIR.0‐12h) and maximum GIR (GIRmax).ResultsEquivalence was demonstrated between Biocon's Insulin‐R and Humulin‐R for the primary PK and PD endpoints. The 90% confidence intervals were within 80.00% to 125.00% limits. The PK and PD profiles were comparable. There were no significant differences in the safety profiles of the two treatments, and no serious adverse events were reported.ConclusionPK and PD equivalence was demonstrated between Biocon's Insulin‐R and Humulin‐R in healthy subjects. Treatment with Biocon’s Insulin‐R and Humulin‐R was well tolerated.

Variation in insulin response to oral sugar test in a cohort of horses throughout the year and evaluation of risk factors for insulin dysregulation

BackgroundThe oral sugar test (OST) is commonly used to diagnose insulin dysregulation (ID) and equine metabolic syndrome; however, possible seasonal changes in OST results have not been evaluated.ObjectiveTo determine the possible variation in insulin response to OST throughout the year and risk factors associated with maximum insulin concentration (InsMax) and ID.Study designProspective, longitudinal cohort study.MethodsThe OST was performed on 29 Finnhorses every other month six times. Serum total adiponectin concentration and phenotypic variables related to obesity were also measured. Changes in InsMax, adiponectin, scale weight, body condition score, cresty neck score (CNS), and fasting glucose concentration were assessed. Risk factor analyses were performed on InsMax and ID status, and ID groups were compared with each other.ResultsFourteen horses were categorised with non‐ID each time and 15 as having ID at least once during the follow‐up period. The ID status of 12 horses varied throughout the year, but neither the insulin variables measured during the OST nor adiponectin expressed significant seasonal variation. Increasing age and CNS, and decreasing adiponectin were observed as risk factors for a high InsMax after OST. The risk of ID was higher in horses with no exercise compared to horses with exercise (OR 7.6, 95% CI 1.2‐49.3, P = .03). Horses with ID had lower serum adiponectin concentrations, longer neck circumference and larger height than horses in the non‐ID group.Main limitationsThe environmental conditions (feeding, exercise) were not constant for all horses throughout the study and only one breed was used.ConclusionsNeither OST results nor adiponectin varies with season; however, there were a substantial number of horses with variable ID status throughout the year, in which repeated OSTs may be beneficial. Lack of exercise was a risk factor for ID.

Increasing preweaning milk replacer supply affects postweaning energy metabolism of Holstein male calves

Male Holstein calves commonly receive minimal quantities of milk replacer (MR) to speed up weaning and reduce costs. Studies with Holstein female calves show that early life feed restriction affects energy metabolism later in life. Aiming to test this hypothesis, 120 Holstein bull calves (48.4 ± 2.2 kg of BW and 20 ± 3.2 d of age) housed in 24 pens were blocked and randomized to two treatments: A low calf MR allowance (LP) (two daily doses of 2 l each, 582 g/d of DM), or a high MR allowance (HP) (two daily meals of 4 l each, 1164 g/d of DM). Calves were weaned at day 49 of the study and slaughtered at 32.8 ± 0.5 weeks of age. Throughout the study, animals had ad libitum access to a common compound feed, straw, and water. Twenty-four animals were randomly selected for an intravenous glucose tolerance test (IVGTT). The IVGTT was performed at week 6 and 12 of the study and consisted of an intravenous glucose infusion and sequential blood sampling up to 90 min after glucose infusions. Calves were heavier for HP until week 12, after which the difference disappeared. By design, the MR intake was higher in the HP group resulting in a higher energy intake and a higher average daily gain in the preweaning phase. Blood glucose curves were not different at week 6, but at week 12, 5 min after the infusion, glucose was higher in HP calves. Insulin curves were not different at week 6. Nevertheless, in week 12, a higher insulin concentration was observed for HP 5, 10, 15, 20, 30, 35, and 45 min’ postinfusion, indicating a higher requirement of insulin to control glycemia. Differences between HP and LP calves were also observed for the quantitative insulin sensitivity check index, maximum insulin concentration, and insulin delta at week 12. Blood glucose reached maximum concentration within 5–10 min of the IVGTT test, and the concentration was, on average, 8.58 and 10.80 mmol/l at weeks 6 and 12, respectively. Insulin reached maximum concentration within 10–15 min of the IVGTT, and concentrations were, on average, 33.32 and 32.61 μUI/ml at weeks 6 and 12, respectively. Doubling MR supply improved animal growth up to weaning, but these differences disappeared by the end of the feeding period. Despite similar responses to glucose infusions preweaning, higher milk supply seemed to decrease insulin sensitivity after weaning.

Effects of an anti-IGF-1 receptor monoclonal antibody on laminitis induced by prolonged hyperinsulinaemia in Standardbred horses.

Currently, there are no registered veterinary drugs for the treatment of endocrinopathic equine laminitis, and although this form of the disease is known to be caused by prolonged hyperinsulinaemia, the mechanism of insulin toxicity is unclear. One possibility is that high concentrations of insulin activate IGF-1 receptors (IGF-1R) in lamellar tissue, leading to uncontrolled cell proliferation and epidermal lamellar dysregulation. An equinized version of a human anti-IGF-1R therapeutic monoclonal antibody (mAb11) was generated to test this theory, using a modification of the prolonged euglycaemic-hyperinsulinaemic clamp technique. Healthy Standardbred horses were infused for 48 h with 0.9% saline (negative-control, n = 6), a combination of insulin (4.5 mIU/kgBW/min) and a variable infusion of 50% glucose to maintain euglycaemia (positive-control, n = 6), or insulin and glucose, preceded by a low dose of mAb11 (20 mg), designed to treat one foot only and delivered by retrograde infusion into one forelimb (mAb-treated, n = 7). Maximum insulin concentrations were 502 ± 54.4 and 435 ± 30.4 μIU/mL in the positive-control and mAb11-treated groups, respectively (P = 0.33). While the control group remained healthy, all the insulin-treated horses developed laminitis within 30 h, as judged by clinical examination, foot radiographs and histological analysis. Some effects of insulin were not attenuated by the antibody, however, relative to the positive-control group, horses treated with mAb11 showed less sinking of the distal phalanx (P < 0.05) and milder histological changes, with markedly less elongation at the tips of the secondary epidermal lamellae (P < 0.05). These differences were apparent in both front feet and were statistically significant when the values for both feet were combined. The results confirm that IGF-1R may have a role in insulin-induced laminitis and suggest that mAb11 warrants further research as a potential agent to prevent or treat the disease.

Determining the nutritional boundaries for replacing lactose with glucose in milk replacers for calves fed twice daily

The effect of replacing lactose with glucose on the gastrointestinal system of young calves at levels above 20% diet inclusion in milk replacer (MR) is not well described. The aim of this study was to determine tolerance to glucose inclusion at the direct expense of lactose on glucose metabolism, health, and growth performance in Holstein male calves. In total, 110 Holstein male dairy calves (16 ± 2.5 d and 50.3 ± 0.2 kg) were acquired from a commercial collection center. After an adaptation period of 3 d, 100 calves were selected for the study based on health parameters. Calves were blocked based on body weight measured on d 4 after arrival. Within each block, calves were randomly assigned to 1 of 5 levels of glucose inclusion (replacing lactose): 0% (L1, n = 20), 10% (L2, n = 20), 20% (L3, n = 20), 30% (L4, n = 20), and 40% (L5, n = 20), leading to an estimated osmolality range from 417 (L1) to 586 mOsm/kg (L5). Carbohydrates were exchanged based on hexose equivalents, and glucose delivery was standardized across treatments, while the rest of the formula (60%) remained unchanged. Calves received L1 during the adaptation period of 3 d and were then exposed to their respective treatment until d 47 after arrival. Milk replacer was provided daily in 2 equally sized meals. Meal size was 2.0 L during the 3-d adaptation period and gradually increased to 4.0 L until weaning (d 35 after arrival). During weaning, meal size decreased from 4.0 to 2.0 L on d 36, and MR was withdrawn on d 48 after arrival. Straw and concentrates were offered ad libitum from d 25 onward. Calves had ad libitum access to water throughout the study. Measurements included daily feed intakes, weekly body weight, and weekly spot feces sampling in all calves. Blood samples were collected on d 18. Additionally, postprandial responses of insulin and glucose were measured in 6 calves per treatment on d 19, 20, and 21. Increasing glucose inclusion (at the direct expense of lactose) in MR did not affect growth but linearly increased mortality, which was as high as 25% (5/20) in L5. Mortality was primarily associated with gastrointestinal disorders (6/11). At higher glucose levels, calves needed greater serum insulin concentrations to control glycemia, as shown by a linear increase in the area under the curve for insulin. Furthermore, calves needed more time to control glycemia, as indicated by a linear increase in the maximal concentration of insulin. Consequently, there was a linear increase in area under the curve for glucose. Even though calves needed more time and higher insulin concentrations for 30% glucose inclusion and higher, the glucose-to-insulin ratio did not differ across treatments. However, high glucose inclusion levels in MR affected calf mortality and is not a suitable strategy for lactose replacement.

Bioequivalence of Ultra Rapid Lispro (URLi) U100 and U200 Formulations in Healthy Subjects.

IntroductionUltra rapid lispro (URLi) is a novel insulin lispro formulation that was developed to more closely match physiological insulin secretion. The aims of this study were to demonstrate the bioequivalence (BE) of a concentrated formulation (U200) of URLi to the U100 formulation of URLi after subcutaneous (SC) administration and to evaluate the glucodynamics (GD) of these formulations.MethodsThis phase 1, randomized, two‐sequence, four‐period, double-blind, replicate crossover study was conducted in 68 healthy subjects. At each dosing visit, subjects received a 15-U SC dose of either U100 URLi or U200 URLi followed by a 10-h euglycemic clamp procedure. Serum insulin lispro and blood glucose concentrations were measured, and the glucose infusion rate was continuously adjusted during the clamp to maintain the target blood glucose.ResultsBioequivalence of U200 URLi relative to U100 URLi was demonstrated. The 90% confidence intervals (CIs) of the ratios of geometric least squares (LS) means for the maximum insulin concentration and total exposure were within the BE limits of 0.80–1.25. Additionally, the 90% CIs for the ratios of geometric LS means for maximum glucose infusion rate and total glucose infused were within the BE limits.The early 50% tmax occurred at approximately the same time for the U100 and U200 URLi formulations, and the insulin exposure within the first 15 min was similar for both formulations. The tolerability of the two URLi formulations was comparable.ConclusionsThis study demonstrated that the U100 and U200 URLi formulations are bioequivalent. The accelerated insulin absorption observed for the U100 formulation was maintained with the U200 URLi formulation. Further, the GD were similar for both formulations, supporting the ability of individuals to transfer from U100 to U200 URLi in a 1:1 unit conversion.Trial RegistrationNCT03616977.

1036-P: Bioequivalence of Ultra-Rapid Lispro (URLi) U100 and U200 Formulations in Healthy Subjects

URLi is a novel insulin lispro formulation developed to more closely match physiological insulin secretion. URLi U200 is a concentrated formulation. This randomized, double-blind, 4-period, replicated crossover, euglycemic clamp study (NCT03616977) assessed pharmacokinetics (PK) and glucodynamics (GD) after 15 U subcutaneous doses of U100 and U200 URLi in 68 healthy subjects (mean ± SD age 39.6 ± 9.6 y). Similar mean PK and GD profiles were observed after dosing U100 and U200 URLi. The formulations were bioequivalent (BE): the 90% CI of ratios of geometric least-square means for the maximum insulin concentration (Cmax) and total exposure (AUC0-∞) were within BE limits of 0.80-1.25. Additionally, the 90% CI for the ratios of geometric means for maximum (Gtot) and total glucose infused (Rmax) were within the BE limits. The time to early half Cmax (early 50% tmax) occurred at approximately the same time for both formulations. Additionally, insulin exposure within the first 15 and 30 minutes was similar for U100 and U200 URLi. The tolerability of the U200 and U100 URLi formulations were comparable. This study demonstrated that U100 and U200 URLi formulations were BE and the faster insulin absorption was maintained in the U200 formulation. The GD were similar and support the ability of patients to transfer from U100 to U200 URLi in a 1:1 unit conversion. Disclosure H. Linnebjerg: Employee; Self; Eli Lilly and Company. Stock/Shareholder; Self; Eli Lilly and Company. E.S. LaBell: Employee; Self; Eli Lilly and Company. Stock/Shareholder; Self; Eli Lilly and Company, Johnson &amp; Johnson, Novartis AG. M.A. Dellva: Employee; Self; Eli Lilly and Company. S. Lim: Employee; Self; Eli Lilly and Company. D.E. Coutant: Employee; Self; Eli Lilly and Company. Employee; Spouse/Partner; Eli Lilly and Company. J. Leohr: None. Funding Eli Lilly and Company

Effects of feeding a high- or moderate-starch prepartum diet to cows on newborn dairy heifer calf responses to intravenous glucose tolerance tests early in life

The objective of this study was to evaluate the effect of feeding a prepartum diet with a high or moderate starch content on growth and insulin sensitivity of female offspring early in life. Thirty-eight Holstein heifer calves were born to dams fed either a high-starch (26% starch on a DM basis, HI; n = 20) or moderate-starch (14% starch on a DM basis, MOD; n = 18) prepartum diet commencing at 28 ± 3 d before expected parturition date. Following birth, all calves were housed individually and fed three 2-L meals of colostrum within the first 24 h of life and offered 10 L/d of milk replacer (26% CP, 18% fat, mixed to 130 g/L). Body weight of calves was measured at birth and on d 2 (after colostrum feeding but before milk feeding), 10 ± 2, and 20 ± 2. A glucose tolerance test was performed at a minimum of 6 h after their last colostrum or milk meal to evaluate insulin sensitivity on d 2, 10 ± 2 and 20 ± 2. Body weight did not differ throughout between HI and MOD calves; however, calves born to primiparous dams were smaller compared with those born to multiparous dams. Glucose or insulin concentrations were not different before the glucose tolerance test. Following the glucose tolerance test, maximum glucose concentrations were not different between treatments at any time point. However, HI calves had greater insulin area under the curve, and HI calves had greater maximum insulin concentrations on d 2. Glucose or insulin clearance rates were not different nor was the calculated insulin sensitivity index between treatments. These findings suggest that feeding a HI prepartum diet may reduce some insulin sensitivity indicators of female offspring early in life.

Insulin and incretin responses to grazing in insulin-dysregulated and healthy ponies.

BackgroundSupraphysiological insulin and incretin responses to a cereal‐based diet have been described in horses and ponies with insulin dysregulation (ID). However, the hormonal responses to grazing have not yet been described.ObjectivesTo determine if there is a difference in the insulin and incretin responses to grazing pasture between insulin‐dysregulated and healthy ponies.AnimalsA cohort of 16 ponies comprising 5 with normal insulin regulation (NIR), 6 with moderate ID (MID), and 5 with severe ID (SID).MethodsIn this case‐control study, an oral glucose test (OGT) was used to determine the insulin responsiveness of each pony to PO carbohydrate before grazing pasture (4 hours) for 3 consecutive days. Serial blood samples collected during grazing were analyzed for glucose, insulin, glucose‐dependent insulinotropic peptide (GIP) and active glucagon‐like peptide‐1 (aGLP‐1), and compared among pony groups and day of pasture access.ResultsThe area under the insulin curve when grazing increased with ID severity (P < .03). The median (range) maximal insulin concentration was greater in the MID (72.5 [129] μIU/mL) and SID (255 [338.5] μIU/mL) groups, compared to the NIR (11.7 [24.9] μIU/mL) group (P < .03) and occurred within 2‐4 hours of grazing. Postprandial OGT insulin concentration was positively correlated with 2 hours post‐grazing insulin across all 3 grazing days (P ≤ .03). The aGLP‐1 and GIP concentrations increased in response to grazing but did not differ among groups.Conclusions and Clinical ImportanceGrazing pasture provoked an increased insulin and incretin response in insulin‐dysregulated ponies within 4 hours of grazing. The pasture and OGT insulin concentrations were correlated.

New Diagnostic Criteria for the Localization of Insulinomas with the Selective Arterial Calcium Injection Test: Decision Tree Analysis

PurposeTo explore optimal diagnostic criteria for localizing insulinomas with the selective arterial calcium injection (SACI) test using decision tree analysis. Materials and MethodsA retrospective study included 86 vessels of 18 patients (5 men, 13 women; mean age 67 y; range, 49–73 y) with insulinomas who underwent SACI test between June 2007 and May 2016. Of 27 insulinomas, 7 were found in the head, 13 in the body, and 7 in the tail of the pancreas. Two patients had multiple tumors. To identify optimal diagnostic criteria, decision tree analysis was performed, and sensitivity, specificity, and accuracy of the conventional and the proposed new diagnostic criteria (plasma insulin concentration after calcium injection [ICpost] > 2.0 × plasma insulin concentration before calcium injection [ICpre]) were compared. ResultsThe proposed new diagnostic criteria for insulinoma obtained by decision tree analysis were (i) ICpost > 2.7 × ICpre and maximum insulin concentration > 60.3 μIU/mL or (ii) ICpost > 2.7 × ICpre and maximum insulin concentration < 60.3 μIU/mL with ICpre being ≥ 7.5 μIU/mL. Sensitivity, specificity, and accuracy of the new criteria for the SACI test were 100%, 91.4%, and 94.2; sensitivity, specificity, and accuracy of conventional criteria were 100%, 69.0%, and 79.1%. ConclusionsNew diagnostic criteria for localization of insulinomas with the SACI test yielded higher diagnostic performance than conventional criteria.

Evaluation of glucose dose on intravenous glucose tolerance test traits in Holstein-Friesian heifers

Glucose metabolism in dairy and beef cattle has received considerable attention because balanced blood glucose is essential for numerous processes, such as milk production and general health. The glucose tolerance test measures the ability of an organism to regulate blood glucose levels. Glucose half-life time (GHLT) has high heritability and could serve as a potential parameter to breed for metabolic resistance. However, studies focusing on identification of an adequate glucose dose have not yet been conducted in cattle. The objective of this study was to analyze the effect of 5 different glucose doses (0.5, 1, 1.5, 2, and 3 g/kg of body weight0.75) on intravenous glucose tolerance test (ivGTT) traits and insulin responses in nongestating heifers. A total of 150 tests were performed in 30 Holstein-Friesian heifers aged 13 to 15 mo. Blood samples were obtained every 7 min after glucose injection until min 63. Glucose traits and insulin parameters included blood serum glucose and insulin concentration at min 0 (basal concentration), min 7 to 21 (peak glucose and insulin concentration), and min 63 (last sampling) relative to glucose administration, glucose and insulin area under the curve (GAUC and IAUC), and GHLT estimated between min 14 and 42. Serum glucose and insulin concentrations were measured according to the hexokinase colorimetric method and radioimmunoassay, respectively. Generalized linear mixed model was used to test for significant differences in ivGTT traits, insulin responses, and glucose elimination rates (k) over time at different glucose doses. Maximum glucose and insulin concentrations at min 63 increased with higher glucose doses. Significantly lower GHLT were obtained at increasing glucose doses, whereas GAUC and IAUC were significantly higher at increasing doses. The k values were affected by glucose dose and by time interval. Glucose dose greatly affected most ivGTT traits, insulin responses, and glucose elimination rates. Therefore, researchers should standardize their methods to achieve repeatable results and use the same time points for GHLT calculation. Higher glucose doses (≥1.5 g/kg of body weight0.75) triggered glucose concentrations above the glucose renal threshold during the initial 42 min, whereas the lowest glucose concentration failed to induce a maximum insulin response. Further research is necessary to determine an adequate dose inducing maximum insulin responses with minimum renal glucose losses.

Pharmacokinetic and Pharmacodynamic Variability of Insulin When Administered by Jet Injection.

Background:Jet injection has been shown to accelerate the absorption and action of rapid-acting insulin. In this study, we compared the variability of absorption characteristics between jet injection and conventional administration of the rapid-acting insulin analogue aspart.Methods:A total of 30 healthy volunteers were enrolled in this randomized controlled blinded parallel study. On two test days, they received insulin aspart (0.2 units/kg body weight), either by jet injection or conventional pen, followed by a 6-hour euglycemic glucose clamp. Plasma glucose and insulin levels and glucose infusion rates were measured every 5 to 10 minutes to calculate the variability in pharmacological endpoints.Results:Jet injection advanced the times until maximal insulin concentration (T-INSmax) and glucose infusion rate (T-GIRmax) by ~40% (both P < .01). The difference between the two test days for these endpoints did not differ between jet injection and conventional administration (T-INSmax: 7.3 ± 1.9 vs 22.3 ± 6.3 min, P = .074; T-GIRmax: 24.0 ± 3.5 vs 27.3 ± 6.6 min, P = .66). The corresponding intraindividual coefficients of variation for injection by jet or conventional pen were 15.3 ± 3.3 and 22.0 ± 4.6% (P = .25, Pvariance = .044) for T-INSmax and 34.5 ± 5.1 and 21.2 ± 4.6% for T-GIRmax (P = .064, Pvariance = .62). The variance in maximal insulin concentration was significantly less after conventional administration (P = .039). The variance in total glucose-lowering effect and total insulin exposure did not differ (P = .93 and P = .32)Conclusion:Using a jet injector for insulin administration was associated with slightly altered variability in pharmacokinetic endpoints, but with about similar variability in pharmacodynamic endpoints compared to conventional administration. Variability in these endpoints remains considerable, regardless of the method of insulin administration.

Lispro administered by the QS-M Needle-Free Jet Injector generates an earlier insulin exposure

ABSTRACTObjective: The aim of this study is to evaluate the pharmacokinetic and pharmacodynamic (PK-PD) profiles of lispro administered by the QS-M needle-free jet injector in Chinese subjects.Research design and methods: A randomized, double-blind, double-dummy, cross-over study was performed. Eighteen healthy volunteers were recruited. Lispro (0.2 units/kg) was administered by the QS-M needle-free jet injector or by conventional pen. Seven-hour euglycemic clamp tests were performed.Results: A larger area under the curve (AUCs) of insulin concentration and glucose infusion rate (GIR) during the first 20 minutes after lispro injection by the jet injector compared to the insulin pen was observed (24.91 ± 15.25 vs. 12.52 ± 7.60 mg. kg−1, P < 0.001 for AUCGIR,0–20 min; 0.36 ± 0.24 vs. 0.10 ± 0.04 U min L−1, P < 0.001 for AUCINS, 0–20 min). Needle-free injection showed a shorter time to reach maximum insulin concentration (37.78 ± 11.14 vs. 80.56 ± 37.18 min, P < 0.001) and GIR (73.24 ± 29.89 vs. 116.18 ± 51.89 min, P = 0.006). There were no differences in total insulin exposure and hypoglycemic effects between the two devices.Conclusion: Lispro administered by QS-M needle-free injector results in earlier and higher insulin exposure than conventional pen, and a greater early glucose-lowering effect with similar overall potency.

Renal Denervation for Resistant Hypertension Fails to Improve Insulin Resistance as Assessed by Hyperinsulinemic-Euglycemic Step Clamp.

We assessed whether insulin sensitivity improved after renal denervation (RDN) for resistant hypertension. Twenty-three patients underwent a two-step hyperinsulinemic-euglycemic clamp (HEC) with glucose tracer and labeled glucose infusion and oral glucose tolerance test (OGTT) before and 6 months after RDN. Eighteen patients had metabolic syndrome at baseline. Blood pressure declined significantly after RDN, whereas mean (SD) fasting plasma glucose concentration (5.9 ± 0.7 mmol/L), median (minimum-maximum) insulin concentration (254 pmol/L [88-797 pmol/L]), and median C-peptide concentration (2.4 nmol/L [0.9-5.7 nmol/L]) remained unchanged. Endogenous glucose release during HEC was less suppressed after RDN, suggesting a slight decrease in hepatic insulin sensitivity. During high-dose insulin infusion, whole-body glucose disposal was low and remained unchanged after RDN, indicating persistent peripheral insulin resistance (IR). Area under the curve for 0-120 min for glucose and insulin during OGTT, Quantitative Insulin Sensitivity Check Index, Simple Index Assessing Insulin Sensitivity Oral Glucose Tolerance, and HOMA-IR were high, and did not improve after RDN. Despite a significant decrease in blood pressure, neither peripheral nor hepatic insulin sensitivity improved 6 months after RDN treatment in this group of insulin-resistant patients without diabetes and with resistant hypertension, as measured with gold standard methods.