Sequential Treatment Escalation with Dapagliflozin and Saxagliptin Improves Beta Cell Function in Type 2 Diabetic Patients on Previous Metformin Treatment: An Exploratory Mechanistic Study.

We investigated the effect of sequential treatment escalation with dapagliflozin and saxagliptin on beta cell function in patients with T2DM insufficiently controlled on metformin monotherapy during a hyperglycaemic clamp investigation. Twenty-six patients (19 males, age 63.5±7.0 years; duration of diabetes 8.8±4.7 years; HbA1c 63.9±15.8 mmol/mol; mean±SD) were enrolled in the study. During a first treatment period (TP1) all patients received 10 mg dapagliflozin for one month, followed by the addition of 5 mg saxagliptin or placebo for another month (TP2). At baseline and at the end of each treatment period, fasting glucose and insulin levels were analysed, and a hyperglycaemic clamp with the measurement of plasma C-peptide, insulin, proinsulin, and glucagon was performed. Treatment with dapagliflozin reduced fasting glucose levels and insulin resistance (TP1). Within the hyperglycaemic clamp, C-peptide and insulin concentrations increased after the addition of dapagliflozin in TP1 (0.48±0.45 nmol*h/l; 6.24±17.9 mU*h/l) and further improved after the addition of saxagliptin in TP2 (0.38±0.34 nmol*h/l; 6.59±10.15 mU*h/l). Acute insulin response did not change after the addition of dapagliflozin (TP1), but significantly improved after the addition of saxagliptin in TP2 (0.89±0.76 mU*h/l). Both drugs improved the C-peptide/proinsulin ratio. After the addition of saxagliptin, the glucagon/insulin ratio significantly declined (TP2). Treatment escalation with dapagliflozin and saxagliptin exhibit additive effects on beta cell capacity, and improves alpha and beta cell integrity.

Effects on α- and ß-cell function of sequentially adding empagliflozin and linagliptin to therapy in people with type 2 diabetes previously receiving metformin: An exploratory mechanistic study.

AIMS: To investigate the effect of sequential treatment escalation with empagliflozin and linagliptin on laboratory markers of α- and ß-cell function in people with type 2 diabetes mellitus (T2DM) insufficiently controlled on metformin monotherapy. RESEARCH DESIGN AND METHODS: A total of 44 people with T2DM received 25 mg empagliflozin for a duration of 1 month in an open-label fashion (treatment period 1 [TP1]). Thereafter, they were randomized to a double-blind add-on therapy with linagliptin 5 mg or placebo (treatment period 2 [TP2]) for 1 additional month. α- and ß-cell function was assessed using a standardized liquid meal test and an intravenous (i.v.) glucose challenge. Efficacy measures comprised the areas under the curve for glucose, insulin, proinsulin and glucagon after the liquid meal test and the assessment of fast and late-phase insulin release after an i.v. glucose load with a subsequent hyperglycaemic clamp. RESULTS: Empagliflozin reduced fasting and postprandial plasma glucose levels, associated with a significant reduction in postprandial insulin levels and an improvement in the conversion rate of proinsulin (TP1). The addition of linagliptin during TP2 further improved postprandial glucose levels, probably as a result of a marked reduction in postprandial glucagon concentrations (TP2). The insulin response to an i.v. glucose load increased during treatment with empagliflozin (TP1), and further improved after the addition of linagliptin (TP2). CONCLUSION: After metformin failure, sequential treatment escalation with empagliflozin and linagliptin is an attractive treatment option because of the additive effects on postprandial glucose control, probably mediated by complementary effects on α- and ß-cell function.

How fast is recovery of impaired glucose tolerance after 21-day bed rest (NUC study) in healthy adults?

AIM: We hypothesized that 4 days of normal daily activity after 21 days of experimental bed rest (BR) will not reverse BR induced impaired glucose tolerance. DESIGN: Glucose tolerance of seven male, healthy, untrained test subjects (age: 27.6 (3.3) years (mean (SD)); body mass: 78.6 (6.4) kg; height: 1.81 (0.04) m; VO2 max: 39.5 (5.4) ml/kg body mass/min) was studied. They stayed twice in the metabolic ward (crossover design), 21 days in bed and 7 days before and after BR each. Oral glucose tolerance tests were applied before, on day 21 of BR, and 5 and 14 days after BR. RESULTS: On day 21 of BR, AUC(120 min) of glucose concentration was increased by 28.8 (5.2)% and AUC(120 min) of insulin by 35.9 (10.2)% (glucose: P < 0.001; insulin: P = 0.02). Fourteen days after BR, AUC(120 min) of serum insulin concentrations returned to pre-bed-rest concentrations (P = 0.352) and AUC(120 min) of glucose was still higher (P = 0.038). Insulin resistance did not change, but sensitivity index was reduced during BR (P = 0.005). CONCLUSION: Four days of light physical workload does not compensate inactivity induced impaired glucose tolerance. An individually tailored and intensified training regime is mandatory in patients being in bed rest to get back to normal glucose metabolism in a reasonable time frame.

Randomized Trial Comparing SGLT2 Inhibition and Hydrochlorothiazide on Sympathetic Traffic in Type 2 Diabetes.

Introduction: Reductions in sympathetic nervous system activity may contribute to beneficial effects of sodium glucose cotransporter 2 (SGLT2) inhibition on cardiovascular outcomes. Therefore, we tested the hypothesis that SGLT2 inhibition with empagliflozin (Empa) lowers muscle sympathetic nerve activity (MSNA) in patients with type 2 diabetes mellitus (T2DM) compared with hydrochlorothiazide (HCT) to discern SGLT2-specific actions from responses to increased natriuresis. Methods: We randomized patients with T2DM on metformin monotherapy to either 25 mg/d Empa (n = 20) or 25 mg/d HCT (n = 21) for 6 weeks in a parallel, double-blind fashion. We assessed MSNA by peroneal microneurography, blood pressure, cardiovascular and metabolic biomarkers at baseline and at the end of treatment. Results: Both drugs elicited volume depletion, as indicated by increased thoracic impedance. Compared with HCT, Empa caused 1.23 kg more body weight loss (P = 0.011) and improved glycemic control. Seated systolic blood pressure decreased with both treatments (P < 0.002). MSNA did not change significantly with either treatment; however, MSNA changes were negatively correlated with changes in body weight on Empa (P = 0.042) and on HCT(P = 0.001). The relationship was shifted to lower MSNA on Empa compared with HCT (P = 0.002). Conclusion: Increased renal sodium excretion eliciting body weight loss may promote sympathetic activation. However, sympathetic excitation in the face of increased sodium loss may be attenuated by SGLT2 inhibitor-specific actions.

Limited evidence for sympathetic neural overactivation in older patients with type 2 diabetes mellitus.

Introduction: Mechanistic studies suggested that excess sympathetic activity promotes arterial hypertension while worsening insulin sensitivity. Older patients with type 2 diabetes are at particularly high cardiovascular and metabolic risk. However, data on sympathetic activity in this population is scarce. Methods: We studied 61 patients with type 2 diabetes mellitus (22 women, 60.9 ± 1.4 years; 39 men, 60.9 ± 1.4 years). They had to have diabetes for at least 2 years, a hemoglobin A1c of 6.5-10%, a body-mass-index of 20-40 kg/m2, and had to be treated with stable doses of metformin only. We recorded ECG, finger and brachial blood pressure, and muscle sympathetic nerve activity (MSNA). Results: MSNA was 37.5 ± 2.5 bursts/min in women and 39.0 ± 2.0 bursts/min in men (p = 0.55). MSNA expressed as burst incidence was 52.7 ± 2.0 bursts/100 beats in women and 59.2 ± 3.1 bursts/100 beats in men (p = 0.21). Five out of 39 men (12.8%) and two out of 22 women (9.1%) exhibited resting MSNA measurements above the 95th percentile for sex and age. In the pooled analysis, MSNA was not significantly correlated with systolic blood pressure, diastolic blood pressure, body mass index, waist circumference, body composition, or HbA1c (r 2 < 0.02, p > 0.26 for all). Discussion: We conclude that relatively few older patients with type 2 diabetes mellitus exhibit increased MSNA. The large interindividual variability in MSNA cannot be explained by gender, blood pressure, body mass index, or glycemic control.

Improving the Assessment of Flow-Mediated Dilation Through Detection of Peak Time in Healthy Subjects and Subjects With Type 2 Diabetes.

The assessment of flow-mediated dilation (FMD) is widely used to quantify endothelial function. Historically, FMD was determined at 60 seconds post-cuff deflation. We investigated whether FMD would be more accurate if determined at maximum dilatory peak (MDP) than at 60 seconds in healthy subjects and subjects with type 2 diabetes mellitus (T2DM). We studied 95 healthy and 72 subjects with T2DM and assessed FMD at MDP, 60 and 90 seconds. Twenty-four healthy and 12 subjects with T2DM underwent a repeat FMD after 28 days. In healthy subjects, FMD at MDP was higher than at 60 and 90 seconds, with mean difference MDP versus 60 seconds 1.14% (95% CI: 0.6-1.7); P < .0001 and MDP versus 90 seconds 1.9% (95% CI: 1.3-2.5) with similar results in T2DM, that is, 1.0% (95% CI: 0.1-1.9) and 2.3% (95% CI: 1.3-3.2), respectively. Intraindividual variability was lowest with MDP compared with 60 and 90 seconds, that is, 15.0 versus 23.2% and 40.0%, respectively, resulting in a more than 2-fold reduction in necessary sample size. In healthy subjects and subjects with T2DM, assessment of FMD using MDP results in a more accurate and precise assessment leading to a substantial reduction in sample size.

Impact of Injection Speed, Volume, and Site on Pain Sensation.

BACKGROUND: Painful subcutaneous insulin injections may decrease treatment compliance. Improving injection comfort therefore represents a particular area of technological research in which steady progress has been made since the introduction of the insulin pen in 1985. Injection pain can be influenced by many variables, but relatively little is known about their impact. This study investigated the impact of injection volume (range 0-2250 µL), speed (range 0-800 µL/sec), and site (abdomen vs thigh) on pain sensation. METHOD: In random order, patients (n = 80) with type 1 or type 2 diabetes received 24 saline injections subcutaneously through a 27G ultra-thin-wall needle. Injections were performed in the abdomen (n = 19) and thigh (n = 5) with predefined speed-volume combinations. For each injected speed-volume combination, patients scored their pain sensation on a 100 mm visual analog scale (VAS). RESULTS: The mean pain scores for speed-volume combinations were all in the lower part (<20 mm) of the VAS, indicating zero to mild pain. Pain sensation was statistically higher ( P < .05) with the 2250 µL volume compared to other injection volumes (range 4.3-5.1 mm) and with thigh compared to abdomen injections (2.1 mm). Pain sensation did not change with increasing injection speed. Patient acceptance of the injection pain was high for all injections (range 93.7-98.7%). CONCLUSIONS: In summary, large volume and thigh injections are rated more painful, but the clinical impact of these findings is likely marginal considering the low absolute pain levels and high patient acceptance rates. Injection speed does not influence pain sensation.

A Comprehensive Performance Evaluation of Five Blood Glucose Systems in the Hypo-, Eu-, and Hyperglycemic Range.

BACKGROUND: The objective was to evaluate the performance (in terms of accuracy, precision, and trueness) of 5 CE-certified and commercially available blood glucose (BG) systems (meters plus test strips) using an innovative clinical-experimental study design with a 3-step glucose clamp approach and frequent capillary BG measurements. METHODS: Sixteen subjects with type 1 diabetes participated in this open label, single center trial. BG was clamped at 3 levels for 60 minutes each: 60-100-200 mg/dL. Medical staff performed regular finger pricks (up to 10 per BG level) to obtain capillary blood samples for paired BG measurements with the 5 BG systems and a laboratory method as comparison. RESULTS: Three BG systems displayed significantly lower mean absolute relative deviations (MARD) (ACCU-Chek® Aviva Nano [5.4%], BGStar® [5.1%], iBGStar® [5.3%]) than 2 others (FreeStyle InsuLinx® [7.7%], OneTouch Verio®IQ [10.3%]). The measurement precision of all BG systems was comparable, but relative bias was also lower for the 3 systems with lower MARD (ACCU-Chek [1.3%], BGStar [-0.9%], iBGStar [1.0%]) compared with the 2 others (FreeStyle [-7.2%], OneTouch [8.9%]). CONCLUSIONS: This 3 range glucose clamp approach enables a systematic performance evaluation of BG systems under controlled and reproducible conditions. The random error of the tested BG systems was comparable, but some showed a lower systematic error than others. These BG systems allow an accurate glucose measurement at low, normal and high BG levels.

Insulin Injection Into Lipohypertrophic Tissue: Blunted and More Variable Insulin Absorption and Action and Impaired Postprandial Glucose Control.

OBJECTIVE: Lipohypertrophy (LHT) is common in insulin-treated patients but its exact impact on insulin absorption and action is unclear. RESEARCH DESIGN AND METHODS: In this crossover study, 13 patients with type 1 diabetes received subcutaneous abdominal injections of 0.15 units/kg insulin lispro into LHT (confirmed by examination and ultrasound) and normal adipose tissue (NAT). On one day, a euglycemic clamp was performed with two injections each into LHT and NAT, and on another day one injection per region was given before a standardized mixed meal (75 g carbohydrates), all in randomized order. RESULTS: Compared with NAT, LHT reduced insulin absorption (mean area under the insulin concentration curve [AUCINS0-4h] 131 vs. 165 h * mU/L [LHT vs. NAT]; Cmax 61 vs. 79 mU/L, P < 0.02, respectively) and effect (areas under glucose infusion rate [GIR] curves [AUCGIR0-4h 625 vs. 775 mg/kg, P < 0.05]) but increased intrasubject variability ([coefficient of variation] AUCINS0-4h 52 vs. 11%, Cmax 55 vs. 15%, AUCGIR0-4h 57 vs. 23%, all P < 0.01). Postprandial blood glucose (BG) concentrations were ≥26% higher with LHT (AUCBG0-5h 731 vs. 513 mg * h/dL, BGmax 199 vs. 157 mg/dL, 2-h BG 150 vs. 104 mg/dL, 5-h BG 145 vs. 81 mg/dL, all P < 0.05) and maximum concentrations occurred later. Hypoglycemia (BG ≤50 mg/dL) occurred numerically less frequently with LHT injection (two vs. six patients), whereas profound hyperglycemia (BG ≥300 mg/dL) only occurred with LHT injection (two patients). Tmax-INS did not differ between LHT and NAT in either study. CONCLUSIONS: Insulin absorption and action are blunted and considerably more variable with LHT injection, leading to profound deterioration in postprandial glucose control.

Characterization of pancreatic NMDA receptors as possible drug targets for diabetes treatment.

In the nervous system, NMDA receptors (NMDARs) participate in neurotransmission and modulate the viability of neurons. In contrast, little is known about the role of NMDARs in pancreatic islets and the insulin-secreting beta cells whose functional impairment contributes to diabetes mellitus. Here we found that inhibition of NMDARs in mouse and human islets enhanced their glucose-stimulated insulin secretion (GSIS) and survival of islet cells. Further, NMDAR inhibition prolonged the amount of time that glucose-stimulated beta cells spent in a depolarized state with high cytosolic Ca(2+) concentrations. We also noticed that, in vivo, the NMDAR antagonist dextromethorphan (DXM) enhanced glucose tolerance in mice, and that in vitro dextrorphan, the main metabolite of DXM, amplified the stimulatory effect of exendin-4 on GSIS. In a mouse model of type 2 diabetes mellitus (T2DM), long-term treatment with DXM improved islet insulin content, islet cell mass and blood glucose control. Further, in a small clinical trial we found that individuals with T2DM treated with DXM showed enhanced serum insulin concentrations and glucose tolerance. Our data highlight the possibility that antagonists of NMDARs may provide a useful adjunct treatment for diabetes.

Variability of skin autofluorescence measurement over 6 and 12 weeks and the influence of benfotiamine treatment.

BACKGROUND: Measurements of skin autofluorescence (SAF) allow for a simple and noninvasive quantification of tissue advanced glycation end-products (AGEs), a marker linked to the risk of diabetes complications. The aim of this study was to test the repeatability of SAF over 6 and 12 weeks and to test whether benfotiamine, a thiamine prodrug suggested to reduce AGEs formation under hyperglycemic conditions, is able to attenuate SAF when administered over 6 weeks. PATIENTS AND METHODS: In a double-blind, placebo-controlled, randomized, crossover study, 22 patients with type 2 diabetes mellitus (T2DM) received 900 mg/day benfotiamine or placebo for 6 weeks (washout period of 6 weeks between). At the beginning and at the end of each treatment period, SAF was assessed in the fasting state, as well as 2, 4, and 6 h following a mixed test meal. RESULTS: The respective intra-individual and inter-individual variability of fasting SAF was 6.9% and 24.5% within 6 weeks and 10.9% and 23.1% within 12 weeks. The respective variability calculated for triplicate comparisons was 9.9% and 27.7%. A short-term therapy with benfotiamine did not influence SAF significantly, nor did we find a significant postprandial SAF increase. CONCLUSIONS: In patients with T2DM, repeated, timely spaced SAF measurements have an intra-subject variability of below 11%. Using these data, sample sizes were calculated for interventional studies aiming at reducing SAF. Benfotiamine treatment for 6 weeks did not significantly influence SAF; for this, a longer-term therapy is probably needed.