Glucagon increases insulin levels by stimulating insulin secretion without effect on insulin clearance in mice

Circulating insulin is dependent on a balance between insulin appearance through secretion and insulin clearance. However, to what extent changes in insulin clearance contribute to the increased insulin levels after glucagon administration is not known. This study therefore assessed and quantified any potential effect of glucagon on insulin kinetics in mice. Prehepatic insulin secretion in mice was first estimated following glucose (0.35 g/kg i.v.) and following glucose plus glucagon (10 μg/kg i.v.) using deconvolution of plasma C-peptide concentrations. Plasma concentrations of glucose, insulin, and glucagon were then measured simultaneously in individual mice following glucose alone or glucose plus glucagon (pre dose and at 1, 5, 10, 20 min post). Using the previously determined insulin secretion profiles and the insulin concentration-time measurements, a population modeling analysis was applied to estimate the one-compartment kinetics of insulin disposition with and without glucagon. Glucagon with glucose significantly enhanced prehepatic insulin secretion (Cmax and AUC_0-20) compared to that with glucose alone (p < 0.0001). From the modeling analysis, the population mean and between-animal SD of insulin clearance was 6.4 ± 0.34 mL/min for glucose alone and 5.8 ± 1.5 mL/min for glucagon plus glucose, with no significant effect of glucagon on mean insulin clearance. Therefore, we conclude that the enhancement of circulating insulin after glucagon administration is solely due to stimulated insulin secretion.     

A Comparison of Twice-Daily Biphasic Insulin Aspart 70/30 and Once-Daily Insulin Glargine in Persons With Type 2 Diabetes Mellitus Inadequately Controlled on Basal Insulin and Oral Therapy: A Randomized,Open-Label Study

ObjectiveTo compare efficacy and safety of biphasic insulin aspart 70/30 (BIAsp 30) with insulin (glargine) in type 2 diabetic patients who were not maintaining glycemic control on basal insulin and oral antidiabetic drugs.MethodsIn a 24-week, open-label, parallel-group trial, type 2 diabetic patients who were not maintaining glycemic control on basal insulin (glargine or neutral protamine Hagedorn) + oral antidiabetic drugs were randomly assigned to twice-daily BIAsp 30 + metformin or oncedaily glargine + metformin + secretagogues (secretagogues were discontinued in the BIAsp 30 arm).ResultsOne hundred thirty-seven patients were randomly assigned to the BIAsp 30 group and 143 patients were randomly assigned to the glargine group. Of 280 patients randomized, 229 (81.8%) completed the study. End-of-trial hemoglobin A_1c reductions were − 1.3% (BIAsp 30) vs − 1.2% (glargine) (treatment difference: 95% confidence interval, − 0.06 [− 0.32 to 0.20]; P = .657). Of patients taking BIAsp 30, 27.3% reached a hemoglobin A_1c level < 7.0% compared with 22.0% of patients taking glargine (treatment difference: P = .388). Glucose increment averaged over 3 meals was lower in the BIAsp 30 arm (treatment difference: − 17.8 mg/dL, P = .001). Fasting plasma glucose reductions from baseline were − 13.8 mg/ dL (BIAsp 30) vs − 42.5 mg/dL (glargine) (P = .0002). Final minor hypoglycemia rate, insulin dose, and weight change were higher in the BIAsp 30 arm (6.5 vs 3.4 events/patient per year, P <.05; 1.19 vs 0.63 U/kg; and 3.1 vs 1.4 kg, P = .0004, respectively).ConclusionsDespite not receiving secretagogues, patients taking BIAsp 30 + metformin achieved similar hemoglobin A_1c levels and lower postprandial plasma glucose compared with those receiving glargine + metformin + secretagogues. The large improvement in the glargine group suggests the patients were not true basal failures at randomization. While switching to BIAsp 30 improves glycemic control in this patient population, remaining on basal insulin and optimizing the dose may be equally effective in the short term. (Endocr Pract. 2011;17:41-50)     

Overcoming Clinical Inertia in the Management of Postoperative Patients with Diabetes

ObjectiveTo assess the impact of an intervention designed to increase basal-bolus insulin therapy administration in postoperative patients with diabetes mellitus.MethodsEducational sessions and direct support for surgical services were provided by a nurse practitioner (NP). Outcome data from the intervention were compared to data from a historical (control) period. Changes in basalbolus insulin use were assessed according to hyperglycemia severity as defined by the percentage of glucose measurements > 180 mg/dL.ResultsPatient characteristics were comparable for the control and intervention periods (all P ≥ .15). Overall, administration of basal-bolus insulin occurred in 9% (8/93) of control and in 32% (94/293) of intervention cases (P < .01). During the control period, administration of basal-bolus insulin did not increase with more frequent hyperglycemia (P = .22). During the intervention period, administration increased from 8% (8/96) in patients with the fewest number of hyperglycemic measurements to 60% (57/95) in those with the highest frequency of hyperglycemia (P < .01). The mean glucose level was lower during the intervention period compared to the control period (149 mg/dL vs. 163 mg/dL, P < .01). The proportion of glucose values > 180 mg/dL was lower during the intervention period than in the control period (21% vs. 31% of measurements, respectively, P < .01), whereas the hypoglycemia (glucose < 70 mg/dL) frequencies were comparable (P = .21).ConclusionAn intervention to overcome clinical inertia in the management of postoperative patients with diabetes led to greater utilization of basal-bolus insulin therapy and improved glucose control without increasing hypoglycemia. These efforts are ongoing to ensure the delivery of effective inpatient diabetes care by all surgical services. (Endocr Pract. 2014;20:320-328)     

Aerobic Fitness and Glycemic Variability in Adolescents with Type 1 Diabetes

ObjectiveThis study examines the association of fitness on glycemic variability (GV) in adolescents with type 1 diabetes mellitus (T1DM). GV has been associated with high frequency of hyper-and hypoglycemia.MethodsNineteen adolescents with T1DM, ages 14 to 19 years, underwent aerobic fitness testing to determine their maximal aerobic capacity (VO₂ max). A continuous glucose monitoring (CGM) device was placed on each subject and worn for 3 to 5 days until a return visit when the subjects underwent a 1-hour treadmill exercise session. Mean amplitude of glycemic excursion (MAGE) was calculated from the CGM data collected between the 2 study visits. Metabolic equivalent (MET), a measure of accumulated metabolic workload during the exercise session, was also calculated.ResultsMean VO₂ max was 46.6 ± 6.8 mL/kg/min, with a range of 34.8 to 57.0 mL/kg/min. Mean MET during the exercise session was 577.2 ± 102.4 and ranged from 354.3 to 716.2 METs. There was an inverse association between VO₂ max and MAGE (r = − 0.46; 95% confidence interval [CI], − 0.01 to − 0.76; P = .048). MET load and MAGE also had an inverse relationship (r = − 0.48; 95% CI, − 0.03 to − 0.77; P = .037).ConclusionGV is inversely associated with fitness and MET load. Aerobic fitness should be promoted in adolescents with T1DM not only because of its multiple beneficial effects but also due to a possible association with GV, leading to fewer extremes in hypo-and hyperglycemia. (Endocr Pract. 2014;20:566-570)     

Salivary mRNA markers having the potential to detect oral squamous cell carcinoma segregated from oral leukoplakia with dysplasia

BackgroundIn the current study the presence of extracellular IL-1B, IL-8, OAZ and SAT mRNAs in the saliva was evaluated as a tool in the early detection of oral squamous cell carcinoma.Methods34 patients with primary oral squamous cell carcinoma stage T₁N₀M₀/T₂N₀M₀, 20 patients with oral leukoplakia and dysplasia (15 patients with mild dysplasia and 5 with severe dysplasia/in situ carcinoma) and 31 matched healthy-control subjects were included in the study. The presence of IL-1B, IL-8, OAZ and SAT mRNA was evaluated in extracellular RNA isolated from saliva samples using sequence-specific primers and real-time RT-PCR. ROC curve analysis was used to estimate the ability of the biomarkers to detect oral squamous cell carcinoma patients.ResultsThe data reveal that the combination of these four biomarkers provides a good predictive probability of up to 80% (AUC = 0.799, p = 0.002) for patients with oral squamous cell carcinoma but not patients suffering from oral leukoplakia with dysplasia. Moreover, the combination of only the two biomarkers (SAT and IL-8) also raises a high predictive ability of 75.5% (AUC = 0.755, p = 0.007) approximately equal to the four biomarkers suggesting the use of the two biomarkers only in the prediction model for oral squamous cell carcinoma patients limiting the economic and health cost in half.ConclusionSAT and IL-8 mRNAs are present in the saliva in high quality and quantity, with a good discriminatory ability for oral squamous cell carcinoma patients only but not for patients with oral leukoplakia and dysplasia an oral potentially malignant disorder.     

Improved Glycemic Control with Insulin Glargine Versus Pioglitazone as Add-On Therapy to Sulfonylurea or Metformin in Patients with Uncontrolled Type 2 Diabetes Mellitus

ObjectiveTo compare glycemic control with add-on insulin glargine versus pioglitazone treatment in patients with type 2 diabetes.MethodsThis 48-week, multicenter, parallel-group, open-label study randomized 389 adults with poorly controlled type 2 diabetes (glycated hemoglobin A1c [A1C], 8.0% to 12.0%), despite ≥ 3 months of sulfonylurea or metformin monotherapy, to receive add-on therapy with insulin glargine or pioglitazone. Outcomes included A1C change from baseline to end point (primary), percentage of patients achieving A1C levels ≤ 7.0%, and changes from baseline in fasting plasma glucose, body mass index, weight, and serum lipids. The safety analysis included incidence of adverse events and rates of hypoglycemia.ResultsAt end point, insulin glargine yielded a significantly greater reduction in A1C in comparison with pioglitazone (-2.48% versus -1.86%, respectively; 95% confidence interval, -0.93 to -0.31; P = .0001, 48-week modified intent-to-treat population). Insulin glargine also yielded significantly greater reductions in fasting plasma glucose at all time points (end point difference, -34.9 mg/ dL; 95% confidence interval, -47.6 to -22.2; P < .0001). In comparison with pioglitazone, insulin glargine resulted in a lower overall incidence of possibly related treatmentemergent adverse events (12.0% versus 20.7%) and fewer study discontinuations (2.2% versus 9.1%), but a higher rate (per patient-year) of confirmed clinically relevant hypoglycemic episodes (blood glucose < 70 mg/dL and all severe hypoglycemia) (4.97 versus 1.04; P <.0001) and severe hypoglycemia (0.07 versus 0.01; P = .0309). Weight and body mass index changes were similar between the 2 treatment groups.ConclusionThe addition of insulin glargine early in the diabetes treatment paradigm in patients for whom sulfonylurea or metformin monotherapy had failed resulted in significantly greater improvements in glycemic control in comparison with the addition of pioglitazone. Although severe hypoglycemia was more frequent in patients with insulin glargine therapy, hypoglycemic events occurred in < 5% of patients in the insulin glargine treatment group. (Endocr Pract. 2010;16:588-599)     

Adding Rapid-Acting Insulin or Glp-1 Receptor Agonist to Basal Insulin: Outcomes in A Community Setting

ObjectiveTo evaluate real-world outcomes in patients with type 2 diabetes mellitus (T2DM) receiving basal insulin who initiate add-on therapy with a rapid-acting insulin (RAI) or a glucagon-like peptide 1 (GLP-1) receptor agonist.MethodsData were extracted retrospectively from a U.S. health claims database. Adults with T2DM on basal insulin who added an RAI (basal + RAI) or GLP-1 receptor agonist (basal + GLP-1) were included. Propensity score matching (with a 1 up to 3 ratio) was used to control for differences in baseline demographics, clinical characteristics, and health resource utilization. Endpoints included prevalence of hypoglycemia, pancreatic events, all-cause and diabetes-related resource utilization, and costs at 1-year follow-up.ResultsOverall, 6,718 matched patients were included: 5,013 basal + RAI and 1,705 basal + GLP1. Patients in both groups experienced a similar proportion of any hypoglycemic event (P = .4079). Hypoglycemic events leading to hospitalization were higher in the basal + RAI cohort (2.7% vs. 1.8%; P = .0444). The basal + GLP-1 cohort experienced fewer all-cause (13.55% vs. 18.61%; P < .0001) and diabetes-related hospitalizations (11.79% vs. 15.68%; P < .0001). The basal + GLP-1 cohort had lower total all-cause health care costs ($18,413 vs. $20,821; P = .0002) but similar diabetes-related costs ($9,134 vs. $8,985; P < .0001) compared with the basal + RAI cohort.ConclusionsAdd-on therapy with a GLP-1 receptor agonist in T2DM patients receiving basal insulin was associated with fewer hospitalizations and lower total all-cause costs compared with add-on therapy using an RAI and could be considered as an alternative to an RAI in certain patients with T2DM who do not achieve effective glycemic control with basal insulin. (Endocr Pract. 2015; 21:68-76)     

Tasa estimada de disposición de glucosa en pacientes menores de 18 años con diabetes mellitus tipo 1 y sobrepeso-obesidad

ObjectiveTo assess the estimated glucose disposal rate (eGDR), insulin dose, and lipoprotein profile in children with type 1 diabetes mellitus (T1DM) and overweight or obesity as compared to children with T1DM and normal weight.MethodsA total of 115 patients (aged 5-16 years) with T1DM on intensive insulin therapy were recruited. The following parameters were measured: weight, height, body mass index, waist and hip circumference, insulin dose, eGDR, glycosylated hemoglobin, blood pressure, and lipoprotein profile. Results were stratified by sex and age.ResultsNo significant differences were found in eGDR between children with normal weight, overweight, and obesity. However, obese children older than 11 years had lower eGDR values (9.3 ± 1.3 vs 10.1 ± 0.8 mg kg^-1min^-1; p < 0.01). Insulin dose was higher in overweight and obese children, especially in IU/m²/day (37.7 vs 36.1 vs 29.4 respectively; p < 0.01). Obese children had higher low-density lipoprotein cholesterol levels than children with overweight and normal weight (106.5 vs 91.7 vs 91.5 mg/dL respectively; p < 0.01). No correlation was found between waist circumference and the different markers of insulin resistance.ConclusionsValues of eGDR values were lower in obese children with T1DM older than 11 years, and this may therefore be considered a marker of insulin resistance. Insulin dose was higher in diabetic patients with overweight or obesity, specially in IU/m²/day. Obese children with T1DM had a lipoprotein profile of cardiovascular risk.     

Activation of alpha adrenergic and muscarinic receptors modifies early glucose suppression of cytoplasmic Ca2+ in pancreatic β-cells

Elevation of glucose induces transient inhibition of insulin release by lowering cytoplasmic Ca²⁺ ([Ca²⁺]_i) below baseline in pancreatic β-cells. The period of [Ca²⁺]_i decrease (phase 0) coincides with increased glucagon release and is therefore the starting point for antisynchronous pulses of insulin and glucagon. We now examine if activation of adrenergic α_2A and muscarinic M₃ receptors affects the initial [Ca²⁺]_i response to increase of glucose from 3 to 20 mM in β-cells situated in mouse islets. In the absence of receptor stimulation the elevation of glucose lowered [Ca²⁺]_i during 90–120 s followed by rise due to opening of voltage-dependent Ca²⁺ channels. The period of [Ca²⁺]_i decrease was prolonged by activation of the α_2A adrenergic receptors (1 μM epinephrine or 100 nM clonidine) and shortened by stimulation of the muscarinic M₃ receptors (0.1 μM acetylcholine). The latter effect was mimicked by the Na/K pump inhibitor ouabain (10–100 μM). The results indicate that prolonged initial decrease (phase 0) is followed by slow [Ca²⁺]_i rise and shorter decrease followed by fast rise. It is concluded that the period of initial decrease of [Ca²⁺]_i regulates the subsequent β-cell response to glucose.     

Reduced Risk of Hypoglycemia with Insulin Degludec Versus Insulin Glargine in Patients with Type 2 Diabetes Requiring High Doses of Basal Insulin: A Meta-Analysis of 5 Randomized Begin Trials

ObjectiveThis meta-analysis of 5 trials from the Phase 3a insulin degludec (IDeg) clinical trial program evaluated the risk of hypoglycemia in a subset of subjects with type 2 diabetes (T2D) who required high basal insulin doses at the end of the trials.MethodsThis meta-analysis compared glycated hemoglobin (HbA_1c), fasting plasma glucose (FPG), basal insulin dose, body weight, and rates of overall and nocturnal confirmed hypoglycemia in a pooled population of T2D subjects using > 60 U basal insulin at trial completion. Five Phase 3a, open-label, randomized, treat-to-target, confirmatory 26-or 52-week trials with IDeg (n = 2,262) versus insulin glargine (IGlar) (n = 1,110) administered once daily were included. Overall confirmed hypoglycemia was defined as self-measured blood glucose < 56 mg/dL or any episode requiring assistance; nocturnal confirmed hypoglycemia had an onset between 00:01 and 05:59 am.ResultsMore than one-third of IDeg-(35%) and IGlar-(34%) treated T2D subjects required > 60 U of basal insulin daily at the ends of the trial. Patients achieved similar mean HbA_1c values (estimated treatment difference [ETD] IDeg - IGlar: 0.05%, P = .44) while mean FPG values were lower with IDeg than IGlar (ETD: - 5.9 mg/ dL, P = .04) at end-of-trial. There was a 21% lower rate of overall confirmed hypoglycemic episodes for IDeg (estimated rate ratio [RR] IDeg/IGlar: 0.79, P = .02) and a 52% lower rate of nocturnal confirmed hypoglycemic episodes for IDeg (RR: 0.48, P < .01).ConclusionIn this post hoc meta-analysis, more than 30% of subjects with T2D required > 60 U/day of basal insulin at the end of the trials. In these individuals, IDeg achieves similar HbA_1c reduction with significantly less overall and nocturnal confirmed hypoglycemia compared with IGlar. (Endocr Pract. 2014;20:285-292)     

Tratamiento de la diabetes mellitus tipo 1 con implante pancreático de células madre adultas autólogas

Background and objectiveType 1 diabetes results from the autoimmune destruction of β cells in the pancreas. Several studies have discussed the ability of adult stem cells to differentiate and function effectively. The aim of this study was to attain fasting glycemia of < 100 mg/dl, or any glycemic value of < 200 mg/dl at any time in the course of the day, and a decrease of at least 50% in the dose of exogenous insulin administration up to 180 days after implantation, as well as C-peptide normalization.Patients and methodTwelve patients with type 1 diabetes mellitus were recruited for autologous bone marrow adult stem cell transplantation through an arterial catheter between October and December 2005. The catheterization was performed through the femoral artery, selectively to the inferior pancreatic artery with a microcatheter, and the implant was delivered to the distal segment. Age ranged between 21 and 60 years. Islet-cell and/or glutamic acid decarboxylase antibodies were negative, C-peptide levels were < 0.05 mg/ml, fasting glycemia was < 180 mg/dl, and glycosylated hemoglobin was < 9%.ResultsThe procedure was carried out uneventfully in all patients. Eleven patients (92%) discontinued the use of rapid-acting insulin and four patients managed total suppression of insulin therapy and showed normal C-peptide, glucose, and glycosylated hemoglobin values. Four patients received less than 66% of the initial total daily insulin dose with an increase in basal C-peptide values. Three patients received less than 50% of the initial total daily dose, with no changes in basal C peptide levels. Of these, two patients resumed initial insulin requirements. Only one patient showed no significant changes after transplantation. After 180 days, no adverse events had occurred.ConclusionsThe procedure is feasible and safe and recovery of gland function was obtained after stem cell implantation.     

Patient-Led Versus Physician-Led Titration of Insulin Glargine in Patients with Uncontrolled Type 2 Diabetes: A Randomized Multinational Atlas Study

ObjectiveSelf-adjustment of insulin dose is commonly practiced in Western patients with type 2 diabetes but is usually not performed in Asian patients. This multinational, 24-week, randomized study compared patient-led with physician-led titration of once-daily insulin glargine in Asian patients with uncontrolled type 2 diabetes who were on 2 oral glucose-lowering agents.MethodsPatient-led (n = 275) or physician-led (n = 277) subjects followed the same dose-titration algorithm guided by self-monitored fasting blood glucose (FBG; target, 110 mg/dL [6.1 mmol/L]). The primary endpoint was change in mean glycated hemoglobin (HbA_1c) at week 24 in the patient-led versus physician-led titration groups.ResultsPatient-led titration resulted in a significantly higher drop in HbA_1c value at 24 weeks when compared with physician-led titration (− 1.40% vs. − 1.25%; mean difference, − 0.15; 95% confidence interval, − 0.29 to 0.00; P = .043). Mean decrease in FBG was greatest in the patient-led group (− 2.85 mmol/L vs. − 2.48 mmol/L; P = .001). The improvements in HbA_1c and FBG were consistent across countries, with similar improvements in treatment satisfaction in both groups. Mean daily insulin dose was higher in the patient-led group (28.9 units vs. 22.2 units; P < .001). Target HbA_1c of < 7.0% without severe hypoglycemia was achieved in 40.0% and 32.9% in the patient-led and physician-led groups, respectively (P = .086). Severe hypoglycemia was not different in the 2 groups (0.7%), with an increase in nocturnal and symptomatic hypoglycemia in the patient-led arm.ConclusionPatient-led insulin glargine titration achieved near-target blood glucose levels in Asian patients with uncontrolled type 2 diabetes who were on 2 oral glucose-lowering drugs, demonstrating that Asian patients can self-uptitrate insulin dose effectively when guided. (Endocr Pract. 2015;21:143-157)     

DA-1229, a novel and potent DPP4 inhibitor, improves insulin resistance and delays the onset of diabetes

AimTo characterize the pharmacodynamic profile of DA-1229, a novel dipeptidyl peptidase (DPP) 4 inhibitor.Main methodsEnzyme inhibition assays against DPP4, DPP8 and DPP9. Antidiabetic effects of DA-1229 in HF-DIO mice and young db/db mice.Key findingsDA-1229 was shown to potently inhibit the DPP4 enzyme in human and murine soluble forms and the human membrane-bound form with IC₅₀ values of 0.98, 3.59 and 1.26 nM, respectively. As a reversible and competitive inhibitor, DA-1229 was more selective to human DPP4 (6000-fold) than to human DPP8 and DPP9. DA-1229 (0.1–3 mg/kg) dose-dependently inhibited plasma DPP4 activity, leading to increased levels of plasma GLP-1 and insulin, and thereby lowering blood glucose levels in mice. In high fat diet-fed (HF) mice, a single oral dose of 100 mg/kg of DA-1229 reduced plasma DPP4 activity by over 80% during a 24 h period. Long-term treatment with DA-1229 for 8 weeks revealed significant improvements in glucose intolerance and insulin resistance, accompanied by significant body weight reduction. However, it remains unclear whether there is a direct causal relationship between DPP4 inhibition and body weight reduction. In young db/db mice, the DA-1229 treatment significantly reduced blood glucose excursions for the first 2 weeks, resulting in significantly lower levels of HbA1c at the end of the study. Furthermore, the pancreatic insulin content of the treatment group was significantly higher than that of the db/db control.SignificanceDA-1229 as a novel and selective DPP4 inhibitor improves the insulin sensitivity in HF mice and delays the onset of diabetes in young db/db mice.     

Effects of omega-3 fatty acids on serum levels of T-helper cytokines in children with asthma

BackgroundThere has been a considerable interest in the potential therapeutic value of dietary supplementation with ω-3 fatty acids in patients with asthma.ObjectivesThis cross-sectional study was designed to identify the effect of ω-3 fatty acids on symptom score, pulmonary function and serum T-helper cytokine concentrations in children with mild to moderate persistent asthma.MethodsA total of 39 patients among 50 volunteers completed this 3-month study. They took a soft gel capsule containing 180 mg EPA and 120 mg DHA daily. Pulmonary function was evaluated in 28 eligible patients by spirometry, and serum levels of Th1, Th2, Th9, Th17 and Th22 cytokines were measured by multiplex cytometric bead assay before and after treatment.ResultsAfter treatment with ω-3, symptom score improved in 28 (72%) patients. The results of spirometry showed remarkable improvement in FEV₁/FVC (P = 0.044) and PEF (P < 0.0001) after treatment, but considering a cut-off of 80%, real improvement was observed in 32% of patients with PEF < 80% which raised above the cut-off after ω-3 treatment (P = 0.004) whereas, FEV₁/FVC changes were above the cut-off value in 89% of the patients. After treatment, IL-17A and TNF-α levels decreased significantly (both P = 0.049).ConclusionOral administration of natural anti-inflammatory products such as ω-3 is a promising complementary approach to managing asthma.     

Endothelium-dependent and -independent vasorelaxation induced by CIJ-3-2F,a novel benzyl-furoquinoline with antiarrhythmic action,in rat aorta

AimsThis study was designed to examine the mechanism of relaxation induced by CIJ-3-2F, a benzyl-furoquinoline antiarrhythmic agent, in rat thoracic aorta at the tissue and cellular levels.Main methodsIsometric tension of rat aortic ring was measured in response to drugs. Ionic channel activities in freshly dissociated aortic vascular smooth muscle cells (VSMCs) were investigated using a whole-cell patch-clamp technique.Key findingsCIJ-3-2F relaxed both phenylephrine (PE) and high KCl (60 mM)-induced contractions with respective pEC₅₀ (-log EC₅₀) values of 6.91 ± 0.07 and 6.32 ± 0.06. Removal of endothelium or pretreatment with nitric oxide (NO)-pathway inhibitors N^ω-nitro-l-arginine methyl ester (L-NAME), N^G-monomethyl-l-arginine (L-NMMA), N⁵-(1-iminoethyl)-l-ornithine (L-NIO), hemoglobin, methylene blue or 1H-[1,2,4]oxadiazolo[4,2-α]quinoxalin-1-one (ODQ) reduced the relaxant effect of CIJ-3-2F. Relaxation to CIJ-3-2F was also attenuated by K⁺ channel blockers tetraethylammonium (TEA) or 4-aminopyridine (4-AP), but not by charybdotoxin plus apamin, iberiotoxin, glibenclamide, or BaCl₂. CIJ-3-2F non-competitively antagonized the contractions induced by PE, Ca²⁺, and Bay K8644 in endothelium-denuded rings. In addition, CIJ-3-2F inhibited both the phasic and tonic contractions induced by PE but did not affect the transient contraction induced by caffeine. CIJ-3-2F reduced the Ba²⁺ inward current through L-type Ca²⁺ channel (IC₅₀ = 4.1 μM) and enhanced the voltage-dependent K⁺ (K_v) current in aortic VSMCs.SignificanceThese results suggest that CIJ-3-2F induced both endothelium-dependent and -independent vasorelaxation; the former is likely mediated by the NO/cGMP pathway whereas the latter is probably mediated through inhibition of Ca²⁺ influx or inositol 1,4,5-triphosphate (IP₃)-sensitive intracellular Ca²⁺ release, or through activation of K_v channels.     

Evolución clínica a 5 años desde el inicio de la insulinoterapia en pacientes con diabetes tipo 2 en España: resultados del estudio EDIN

ObjectivesThe primary study objective was to assess the proportion of patients with type 2 diabetes and an HbA_1c value ≤ 6.5% from the start of insulin therapy to five years later in the outpatient setting in Spain.Material and methodsThis was an observational, multicenter, naturalistic study with retrospective collection of clinical data. Investigators were endocrinologists or internal medicine specialists from all over Spain. During standard clinical care, patients started insulin therapy, which was continued for at least 5 years.ResultsThe clinical records of 405 patients were reviewed. The final analysis set included records from 346 patients. At baseline (start of insulin therapy), 51.2% of patients were female; mean (SD) age was 64.6 (9.0) years; body mass index, 29.8 (4-5) kg/m²; time since diagnosis, 8.8 (6.8) years; HbA_1c, 9.4% (1.5); fasting glucose, 223.7 (55.9) mg/dL; and mean 2-hour postprandial glucose, 293.6 (71.0) mg/dL. When insulin therapy was started, < 1.0% of patients had an HbA_1c value ≤ 6.5%. At 5 years, 10.3% of patients achieved the HbA_1c goal of ≤ 6.5% (mean, 7.72%). All glucose parameters (HbA_1c, fasting glucose, and 2-hour postprandial glucose) improved at 5 years as compared to values at the start of insulin therapy.ConclusionsGlucose parameters improved over time in patients with type 2 diabetes in this naturalistic study. However, blood glucose control exceeded the internationally recommended target values. These results therefore suggest that there is still some margin for improvement in outpatient care in Spain.     

Successful treatment of prediabetes in clinical practice: targeting insulin resistance and β-cell dysfunction

ObjectiveTo determine the effectiveness of targeted pharmacologic interventions to reverse documented pathophysiologic abnormalities in prediabetes.MethodsPatients with impaired glucose tolerance (IGT) and/or impaired fasting glucose (IFG) were treated with insulin sensitizers (pioglitazone + metformin) or insulin sensitizers + exenatide on the basis of oral glucose tolerance testing-derived indices of insulin resistance and impaired b-cell function. Patients who declined pharmacologic therapy received lifestyle modification only.ResultsOne hundred five patients with IGT and/or IFG were treated with insulin sensitizers (pioglitazone + metformin) (n = 40), insulin sensitizers + exenatide (n = 47), or lifestyle modification only (n = 18). After a mean follow-up period of 8.9 months, the lifestyle modification group demonstrated no significant changes in fasting plasma glucose, plasma glucose area under the curve during oral glucose tolerance testing, insulin sensitivity, or b-cell function. In the pioglitazone + metformin group (24 hours off medication), fasting plasma glucose fell from 109 to 102 mg/dL; plasma glucose area under the curve decreased by 12.0%; insulin sensitivity and b-cell function improved by 42% and 50%, respectively (all P < .001); 14.3% converted to normal glucose tolerance; and no patient developed diabetes. In the pioglitazone + metformin + exenatide group (24 hours off medication), fasting plasma glucose fell from 109 to 98 mg/dL; plasma glucose area under the curve decreased by 21.2%; insulin sensitivity and b-cell function improved by 52% and 109%, respectively (all P < .001); 59.1% of patients with IGT reverted to normal glucose tolerance; and no patient developed diabetes.ConclusionsTargeted pathophysiologic therapy based on oral glucose tolerance test-derived measures of insulin sensitivity and b-cell function can be implemented in general internal medicine and endocrine practice and is associated with marked improvement in glucose tolerance and reversion of prediabetes to normal glucose tolerance in more than 50% of patients. (Endocr Pract. 2012;18: 342-350)     

Colesevelam Hydrochloride Added to Background Metformin Therapy in Patients with Type 2 Diabetes Mellitus: A Pooled Analysis from 3 Clinical Studies

ObjectiveTo evaluate the glucose- and lipid-altering efficacy of colesevelam hydrochloride (HCl) when added to background metformin therapy in patients with inadequately controlled type 2 diabetes mellitus (T2DM).MethodsThis post hoc analysis included patients with T2DM from 3 randomized, double-blind, placebo- controlled pivotal studies who received metformin as part of their background antidiabetes therapy. In the pivotal studies, patients with T2DM were randomly assigned to receive colesevelam HCl (3.75 g/d) or placebo added to existing metformin (26 weeks), sulfonylurea (26 weeks), or insulin (16 weeks) monotherapy or combination therapy, wherein the combination therapies may have included metformin.ResultsIn this pooled analysis of 696 patients with T2DM who were receiving metformin monotherapy or metformin combined with other antidiabetes therapies, 355 were randomly assigned to receive colesevelam HCl and 341 to receive placebo. In comparison with placebo, colesevelam HCl significantly reduced hemoglobin A_1c (A1C) and fasting plasma glucose (mean treatment difference: -0.50% and -15.7 mg/dL, respectively; P < .001 for both), as well as significantly reduced levels of low-density lipoprotein cholesterol (LDL-C; mean treatment difference: -16.5%), total cholesterol (TC; -5.8%), non-high-density lipoprotein cholesterol (non-HDL-C; -8.2%), and apolipoprotein (apo) B (-7.6%) (P < .0001 for all). Median triglyceride levels were increased with colesevelam HCl (median treatment difference: + 12.8%; P < .0001). In comparison with placebo, colesevelam HCl significantly increased apo A-I (mean treatment difference: + 3.3%; P < .0001), whereas the mean increase in HDL-C with colesevelam HCl was not significant. Colesevelam HCl therapy was generally well tolerated.ConclusionWhen added to metformin-including therapy, colesevelam HCl significantly reduced A1C and fasting glucose, as well as levels of LDL-C, TC, non- HDL-C, and apo B in patients with inadequately controlled T2DM. (Endocr Pract. 2011;17:933-938)     

Comparative effects of intraduodenal fat and glucose on the gut-incretin axis in healthy males

BackgroundThe interaction of nutrients with the small intestine stimulates the secretion of numerous enteroendocrine hormones that regulate postprandial metabolism. However, differences in gastrointestinal hormonal responses between the macronutrients are incompletely understood. In the present study, we compared blood glucose and plasma hormone concentrations in response to standardised intraduodenal (ID) fat and glucose infusions in healthy humans.MethodsIn a parallel study design, 16 healthy males who received an intraduodenal fat infusion were compared with 12 healthy males who received intraduodenal glucose, both at a rate of 2 kcal/min over 120 min. Venous blood was sampled at frequent intervals for measurements of blood glucose, and plasma total and active glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), insulin and glucagon.ResultsPlasma concentrations of the incretin hormones (both total and active GLP-1 and GIP) and glucagon were higher, and plasma insulin and blood glucose concentrations lower, during intraduodenal fat, when compared with intraduodenal glucose, infusion (treatment by time interaction: P < 0.001 for each).ConclusionsCompared with glucose, intraduodenal fat elicits substantially greater GLP-1, GIP and glucagon secretion, with minimal effects on blood glucose or plasma insulin in healthy humans. These observations are consistent with the concept that fat is a more potent stimulus of the ‘gut-incretin’ axis than carbohydrate.     

p11 modulates calcium handling through 5-HT4R pathway in rat ventricular cardiomyocytes

BackgroundThe role of the serotonin receptor 4 (5-HT₄R) pathway in cardiac excitation-contraction coupling (ECC) remains unclear. In the brain, induction of the calcium (Ca²⁺)-binding protein p11 enhances 5-HT₄R translocation and signaling and could therefore be considered as a modulator of the 5-HT₄R pathway in the myocardium. p11 expression is increased by brain-derived neurotrophic factor (BDNF) or antidepressant drugs (imipramine). Thus, we investigated whether p11 regulates the 5-HT₄R pathway in the heart in physiological conditions or under pharmacological induction and the effects on calcium handling.Methods and resultsp11 expression was induced in vivo in healthy Wistar rats by imipramine (10 mg/kg/21 days) and in vitro in left ventricular cardiomyocytes exposed to BDNF (50 ng/ml/8 h). Cell shortening and real-time Ca²⁺ measurements were processed on field-stimulated intact cardiomyocytes with the selective 5-HT₄R agonist, prucalopride (1 μM). Both imipramine and BDNF-induced cardiomyocyte p11 expression unmasked a strong response to prucalopride characterized by an increase of both cell shortening and Ca²⁺ transient amplitude compared to basal prucalopride associated with a high propensity to trigger diastolic Ca²⁺ events. Healthy rats treated with BDNF (180 ng/day/14 days) exhibited a sustained elevated heart rate following a single injection of prucalopride (0.1 mg/kg) which was not observed prior to treatment.ConclusionsWe have identified a novel role for p11 in 5-HT₄R signaling in healthy rat ventricular cardiomyocytes. Increased p11 expression by BDNF and imipramine unraveled a 5-HT₄R-mediated modulation of cardiac Ca²⁺ handling and ECC associated with deleterious Ca²⁺ flux disturbances. Such mechanism could partly explain some cardiac adverse effects induced by antidepressant treatments.