Effect of once-weekly semaglutide on the counterregulatory response to hypoglycaemia in people with type 2 diabetes: A randomized, placebo-controlled, double-blind, crossover trial.

AIMS: To investigate the effects of semaglutide vs placebo on glucagon and other counterregulatory hormones during hypoglycaemia in type 2 diabetes (T2D). METHODS: In this double-blind, placebo-controlled, single-centre trial, we randomized 38 men and women (treated only with metformin) 1:1 to 2 12-week crossover periods of once-weekly subcutaneous semaglutide or placebo, each followed by a hypoglycaemic clamp procedure. The primary endpoint was change in glucagon concentration from target plasma glucose (PG) level 5.5 mmol/L to nadir (target 2.5 mmol/L). RESULTS: The mean (range) participant age was 54.2 (41-64) years, body mass index 29.4 (23.3-36.1) kg/m2 , glycated haemoglobin 60.8 (44.3-83.6) mmol/mol (7.7 [6.2-9.8]%), and diabetes duration 4.5 (0.3-13.2) years. A total of 35 participants completed the trial and were included in the analyses. During the hypoglycaemic clamp from 5.5 mmol/L PG to nadir, the absolute change in mean glucagon concentration was similar for semaglutide vs placebo: 88.3 vs 83.1 pg/mL (estimated difference 5.2 pg/mL [95% confidence interval -7.7 to 18.1]). Concentrations of other counterregulatory hormones increased with both treatments, with a statistically significantly lower increase for noradrenaline and cortisol with semaglutide vs placebo. The glucose infusion rate to maintain constant clamp levels was similar for each treatment group, suggesting an overall similar counterregulatory response. The mean hypoglycaemic symptom score and proportion of participants recognizing hypoglycaemia during the study were lower for semaglutide vs placebo treatment at nadir, but cognitive function test results were similar. No new safety issues were observed for semaglutide. CONCLUSIONS: Semaglutide treatment did not compromise the counterregulatory glucagon response during experimental hypoglycaemia in people with T2D.

Insulin degludec is not associated with a delayed or diminished response to hypoglycaemia compared with insulin glargine in type 1 diabetes: a double-blind randomised crossover study.

AIMS/HYPOTHESIS: Insulin degludec (Des(B30)LysB29(γ-Glu Nε-hexadecandioyl) human insulin; IDeg) is a new basal insulin with an ultra-long flat action profile. The acute physiological responses to hypoglycaemia with IDeg and insulin glargine (A21Gly,B31Arg,B32Arg human insulin; IGlar) were compared. METHODS: Twenty-eight adult type 1 diabetic patients with normal hypoglycaemia awareness (age = 41 ± 12 years, HbA1c = 7.8 ± 0.6% [62.8 ± 7 mmol/mol]) were randomised to once-daily IDeg or IGlar for 5 days in a two-period crossover design. Participants and research staff were blinded to group assignment. Patients were assigned the lowest available randomisation number from a set of blinded randomisation codes provided by the trial sponsor. Hypoglycaemia was induced by administering three times the usual daily insulin dose at midnight on day 5. Plasma glucose (PG) was stabilised by glucose clamp (5.5 mmol/l) for 7-9 h post dosing. Next morning, PG was allowed to decrease stepwise from 5.5 to 3.5 mmol/l (maintained for 30 min) to 2.5 mmol/l (for 15 min). PG was then increased to 3.9 mmol/l (for 120 min), before being returned to baseline. Hypoglycaemic symptom score (HSS), hypoglycaemic awareness, cognitive function, counter-regulatory hormones and vital signs were assessed during each glucose plateau. The primary analysis was to compare IDeg vs IGlar with respect to HSS at nadir PG concentration (2.5 mmol/l). RESULTS: The full analysis set for treatment comparisons comprised data from all 28 exposed patients. Rates of PG decline and PG at nadir were similar for IDeg and IGlar. No treatment differences in HSS (estimated difference: 0.17 [95% CI -1.71, 2.05]; p > 0.05), cognitive function or awareness were observed at any time. Growth hormone and cortisol responses during hypoglycaemia were greater with IDeg than IGlar (AUC treatment ratio [IDeg/IGlar]: 2.44 [1.30, 4.60], p < 0.01; and 1.23 [1.01, 1.50]; p < 0.05), and adrenaline (epinephrine) responses trended higher (1.40 [0.96, 2.04], p = 0.07). The rates of recovery from hypoglycaemia were similar. CONCLUSIONS/INTERPRETATION: IDeg and IGlar elicit comparable symptomatic and cognitive responses to induced hypoglycaemia. IDeg may elicit a moderately greater endocrine response, but times to PG recovery were similar for the two insulins. TRIAL REGISTRATION: ClinicalTrials.gov NCT01002768. FUNDING: Novo Nordisk.

Effect of Liraglutide Treatment on Whole-body Glucose Fluxes in C-peptide-Positive Type 1 Diabetes During Hypoglycemia.

CONTEXT: The effect of liraglutide in C-peptide-positive (C-pos) type 1 diabetes (T1D) patients during hypoglycemia remains unclear. OBJECTIVE: To investigate the effect of a 12-week liraglutide treatment on the body glucose fluxes during a hypoglycemic clamp in C-pos T1D patients and its impact on the alpha- and beta-cell responses during hypoglycemia. DESIGN: This was a randomized, double-blind, crossover study. Each C-pos T1D patient was allocated to the treatment sequence liraglutide/placebo or placebo/liraglutide with daily injections for 12 weeks adjunct to insulin treatment, separated by a 4-week washout period. SETTING AND PARTICIPANTS: Fourteen T1D patients with fasting C-peptide ≥ 0.1 nmol/L. INTERVENTION(S): All patients underwent a hyperinsulinemic-stepwise-hypoglycemic clamp with isotope tracer [plasma glucose (PG) plateaus: 5.5, 3.5, 2.5, and 3.9 mmol/L] after a 3-month liraglutide (1.2 mg) or placebo treatment. MAIN OUTCOME MEASURE(S): The responses of endogenous glucose production (EGP) and rate of peripheral glucose disposal (Rd) were similar for liraglutide and placebo treatment during the clamp. RESULTS: The numbers of hypoglycemic events were similar in both groups. At the clamp, mean glucagon levels were significantly lower at PG plateau 5.5 mmol/L in the liraglutide than in the placebo group but showed similar responses to hypoglycemia in both groups. Mean C-peptide levels were significantly higher at PG-plateaus 5.5 and 3.5 mmol/L after liraglutide treatment, but this effect was not reflected in EGP and Rd. Hemoglobin A1c and body weight were lower, and a trend for reduced insulin was seen after liraglutide treatment. CONCLUSIONS: The results indicate that 3 months of liraglutide treatment does not promote or prolong hypoglycemia in C-pos T1D patients.

Evaluation of a novel, rapid antigen detection test for the diagnosis of SARS-CoV-2.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing coronavirus disease 2019 (COVID-19) is currently finally determined in laboratory settings by real-time reverse-transcription polymerase-chain-reaction (rt-PCR). However, simple testing with immediately available results are crucial to gain control over COVID-19. The aim was to evaluate such a point-of-care antigen rapid test (AG-rt) device in its performance compared to laboratory-based rt-PCR testing in COVID-19 suspected, symptomatic patients. METHODS: For this prospective study, two specimens each of 541 symptomatic female (54.7%) and male (45.3%) patients aged between 18 and 95 years tested at five emergency departments (ED, n = 296) and four primary healthcare centres (PHC, n = 245), were compared, using AG-rt (positive/negative/invalid) and rt-PCR (positive/negative and cycle threshold, Ct) to diagnose SARS-CoV-2. Diagnostic accuracy, sensitivity, specificity, positive predictive values (PPV), negative predictive value (NPV), and likelihood ratios (LR+/-) of the AG-rt were assessed. RESULTS: Differences between ED and PHC were detected regarding gender, age, symptoms, disease prevalence, and diagnostic performance. Overall, 174 (32.2%) were tested positive on AG-rt and 213 (39.4%) on rt-PCR. AG correctly classified 91.7% of all rt-PCR positive cases with a sensitivity of 80.3%, specificity of 99.1%, PPV of 98.3, NPV of 88.6%, LR(+) of 87.8, and LR(-) of 0.20. The highest sensitivities and specificities of AG-rt were detected in PHC (sensitivity: 84.4%, specificity: 100.0%), when using Ct of 30 as cut-off (sensitivity: 92.5%, specificity: 97.8%), and when symptom onset was within the first three days (sensitivity: 82.9%, specificity: 99.6%). CONCLUSIONS: The highest sensitivity was detected with a high viral load. Our findings suggest that AG-rt are comparable to rt-PCR to diagnose SARS-CoV-2 in COVID-19 suspected symptomatic patients presenting both at emergency departments and primary health care centres.

Interleukin-6 produced in subcutaneous adipose tissue is linked to blood pressure control in septic patients.

Cytokines are inflammatory mediators of major relevance during sepsis. Recent evidence shows that adipose tissue can produce many distinct cytokines under physiological and pathological conditions, but the role of cytokines produced in adipose tissue was not addressed in sepsis. In the present study the open-flow microperfusion (OFM) technique was used to investigate whether the cytokines produced in subcutaneous adipose tissue (SAT) of patients with severe sepsis correlate with clinical variables. Interstitial fluid effluent samples were collected using an OFM catheter inserted in the abdominal SAT of nine patients with severe sepsis. Blood samples were withdrawn concomitantly and interleukin-1beta (IL-1beta), IL-8, IL-6 and tumor necrosis factor alpha (TNF-alpha) were measured both in SAT effluent and serum samples. Different time profiles were registered for each cytokine. IL-1beta increased in a time-dependent manner, indicating a localized response against the catheter insertion. Interleukin-1beta, 6 and 8 were higher in SAT than in serum suggesting they were locally produced. Diastolic blood pressure (DBP) negatively correlated with IL-1beta, IL-6 and IL-8 in SAT indicating a possible interaction between adipose tissue inflammation and vascular tone regulation. A multiple regression analysis disclosed that mean DBP was significantly related to IL-6 concentrations in SAT (B=-43.9; R-square=0.82; P=0.002).

The effect of terbutaline on the absorption of pulmonary administered insulin in subjects with asthma.

AIM: To investigate the effect of prior administration of a bronchodilator on the absorption of inhaled insulin in people with asthma treated with inhaled corticosteroids. METHODS: A single-centre, randomized, open-label, two-period cross-over trial was carried out in 41 nondiabetic subjects with asthma treated with inhaled steroids, with reversible bronchoconstriction (Rev+; n= 25) or without reversible bronchoconstriction (Rev-; n= 16). A dose of 0.10 U kg(-1) inhaled human insulin was administered on each dosing day with or without prior administration of the bronchodilator terbutaline (in random order). RESULTS: Prior administration of terbutaline led to a 44% increase in absorption of insulin over 6 h for the Rev+ group compared with no prior administration of bronchodilator [ratio (95% confidence interval) 1.44 (1.13, 1.82), P= 0.004], whereas no effect was seen for the Rev- or the whole group. The maximum insulin concentration (C(max)) increased by 34% for the Rev+ group (P = 0.018) and 17% for the whole group (P= 0.046), whereas no significant effect of prior terbutaline administration was seen for Rev-. The time to C(max) was not significantly different for the Rev+ group, whereas it was approximately 30% longer after bronchodilator administration for the Rev- group (P= 0.044) and the whole group (P= 0.032). CONCLUSIONS: In people with asthma and reversible bronchoconstriction, the administration of a bronchodilator prior to administration of inhaled insulin led to increased absorption of insulin, whereas no effect on insulin absorption in subjects without significant reversibility could be detected.

The effect of exercise on the absorption of inhaled human insulin in healthy volunteers.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: Exercise is known to affect absorption of other inhaled substances, but so far there are no reports on the effect of exercise on the absorption of inhaled insulin in humans. WHAT THIS PAPER ADDS: This report is the first to investigate the effect of exercise on the absorption of inhaled insulin. In this study in healthy volunteers we found that exercise early after dosing increased absorption (15-20%) of inhaled insulin over the first 2 h after start of exercise, with an approximately 30% increase in maximal insulin concentration, and unchanged overall absorption. AIMS: To investigate the effect of moderate exercise on the absorption of inhaled insulin. METHODS: A single-centre, randomized, open-label, three-period cross-over trial was carried out in 12 nonsmoking healthy subjects. A dose of 3.5 mg inhaled human insulin was administered via a nebulizer and followed in random order by either 1) no exercise (NOEX), 2) 30 min exercise starting immediately after dosing (EX0), or 3) 30 min exercise starting 30 min after dosing (EX30). The study was carried out as a 10 h euglycaemic glucose clamp (90 mg dl(-1) (5.0 mmol l(-1))). RESULTS: The absorption of insulin over the first 2 h after start of exercise was 16% increased for EX0 (ratio (95%CI) 1.16 (1.04, 1.30), P = 0.01) and 20% increased for EX30 (1.20 (1.05, 1.36), P < 0.01), both compared with NOEX; the overall insulin absorption during 6 h and 10 h after dosing was not influenced by exercise. The maximum insulin concentration (C(max)) increased by 32% for EX0 and 35% for EX30 (both P < 0.01) compared with NOEX, while the time to C(max) was 31 min faster for EX0 (P < 0.01), but not significantly different after EX30, compared with NOEX. CONCLUSIONS: A significant and clinically relevant increase of insulin absorption over the first 2 h after the beginning of exercise was observed. Until data from studies using the specific insulin inhalers exists, patients using inhaled insulin should be made aware of a potential increased absorption and higher concentration of insulin in connection with exercise.

Impact of C-Peptide Status on the Response of Glucagon and Endogenous Glucose Production to Induced Hypoglycemia in T1DM.

Context: Complete loss of ß-cell function in patients with type 1 diabetes mellitus (T1DM) may lead to an increased risk of severe hypoglycemia. Objective: We aimed to determine the impact of C-peptide status on glucagon response and endogenous glucose production (EGP) during hypoglycemia in patients with T1DM. Design and Setting: We conducted an open, comparative trial. Patients: Ten C-peptide positive (C-pos) and 11 matched C-peptide negative (C-neg) patients with T1DM were enrolled. Intervention: Plasma glucose was normalized over the night fast, and after a steady-state (baseline) plateau all patients underwent a hyperinsulinemic, stepwise hypoglycemic clamp with glucose plateaus of 5.5, 3.5, and 2.5 mmol/L and a recovery phase of 4.0 mmol/L. Blood glucagon was measured with a specific and highly sensitive glucagon assay. EGP was determined with a stable isotope tracer technique. Main Outcome Measure: Impact of C-peptide status on glucagon response and EGP during hypoglycemia. Results: Glucagon concentrations were significantly lower in C-pos and C-neg patients than previously reported. At baseline, C-pos patients had higher glucagon concentrations than C-neg patients (8.39 ± 4.6 vs 4.19 ± 2.4 pmol/L, P = 0.016, mean ± standard deviation) but comparable EGP rates (2.13 ± 0.2 vs 2.04 ± 0.3 mg/kg/min, P < 0.391). In both groups, insulin suppressed glucagon levels, but hypoglycemia revealed significantly higher glucagon concentrations in C-pos than in C-neg patients. EGP was significantly higher in C-pos patients at hypoglycemia (2.5 mmol/L) compared with C-neg patients. Conclusions: Glucagon concentrations and EGP during hypoglycemia were more pronounced in C-pos than in C-neg patients, which indicates that preserved ß-cell function may contribute to counterregulation during hypoglycemia in patients with T1DM.

A prolonged run-in period of standard subcutaneous microdialysis ameliorates quality of interstitial glucose signal in patients after major cardiac surgery.

We evaluated a standard subcutaneous microdialysis technique for glucose monitoring in two critically ill patient populations and tested whether a prolonged run-in period improves the quality of the interstitial glucose signal. 20 surgical patients after major cardiac surgery (APACHE II score: 10.1 ± 3.2) and 10 medical patients with severe sepsis (APACHE II score: 31.1 ± 4.3) were included in this investigation. A microdialysis catheter was inserted in the subcutaneous adipose tissue of the abdominal region. Interstitial fluid and arterial blood were sampled in hourly intervals to analyse glucose concentrations. Subcutaneous adipose tissue glucose was prospectively calibrated to reference arterial blood either at hour 1 or at hour 6. Median absolute relative difference of glucose (MARD), calibrated at hour 6 (6.2 (2.6; 12.4) %) versus hour 1 (9.9 (4.2; 17.9) %) after catheter insertion indicated a significant improvement in signal quality in patients after major cardiac surgery (p < 0.001). Prolonged run-in period revealed no significant improvement in patients with severe sepsis, but the number of extreme deviations from the blood plasma values could be reduced. Improved concurrence of glucose readings via a 6-hour run-in period could only be achieved in patients after major cardiac surgery.

Steady state is reached within 2-3 days of once-daily administration of degludec, a basal insulin with an ultralong duration of action.

BACKGROUND: Various factors influence the pharmacokinetic and pharmacodynamic properties of insulin analogs. The aim of the present study was to determine time to steady state of insulin degludec (IDeg), a basal insulin analog with an ultralong duration of action, after once-daily subcutaneous administration in subjects of varying age, diabetes type, and ethnicity. METHODS: Time to steady state was analyzed in 195 subjects across five Phase I randomized single-center double-blind studies: three in subjects with type 1 diabetes (T1DM), including one in elderly subjects, and two in subjects with type 2 diabetes (T2DM), including one with African American and Hispanic/Latino subpopulations. Subjects received once-daily IDeg (100 U/mL, s.c.) at doses of 0.4-0.8 U/kg for 6-12 days. Time to clinical steady state was measured from first dose until the serum IDeg trough concentration exceeded 90% of the final plateau level. The IDeg concentrations were log-transformed and analyzed using a mixed-effects model with time from first dose and dose level (where applicable) as fixed effects, and subject as a random effect. RESULTS: Steady state serum IDeg concentrations were reached after 2-3 days in all subjects. In trials with multiple dose levels, time to steady state was independent of dose level in T1DM (P = 0.51) and T2DM (P = 0.75). CONCLUSIONS: Serum IDeg concentrations reached steady state within 2-3 days of once-daily subcutaneous administration in all subjects with T1DM or T2DM, including elderly and African American and Hispanic/Latino subjects. At steady state, serum IDeg concentrations were unchanged from day to day.

The Distinct Prandial and Basal Pharmacodynamics of IDegAsp Observed in Younger Adults Are Preserved in Elderly Subjects with Type 1 Diabetes.

BACKGROUND: Management of diabetes in elderly patients is complicated by the elevated risk of insulin-induced hypoglycaemia. This is the first study to report the pharmacodynamic and pharmacokinetic characteristics of IDegAsp (insulin degludec [IDeg]/insulin aspart [IAsp]), a soluble co-formulation of a long-acting basal insulin analogue (IDeg) and a rapid-acting insulin analogue (IAsp) in a single injection, in elderly and younger adult subjects with type 1 diabetes using a glucose clamp. METHODS: In this randomised, single-centre, double-blind, single-dose (SD), two-period, crossover trial, 15 elderly subjects (aged ≥ 65 years) and 13 younger adults (aged 18-35 years) with type 1 diabetes were randomly assigned to two SD administrations of 0.5 U/kg IDegAsp or biphasic insulin aspart 30 (control) followed by a 26-h euglycaemic glucose clamp and 120-h pharmacokinetic blood sampling. The glucose infusion rate (GIR) profiles were extrapolated to simulated steady-state (SS) conditions using pharmacodynamic models. RESULTS: IDegAsp GIR profiles showed a distinct peak and rapid onset of action from IAsp followed by a separate and flat basal action from IDeg. Mean 24-h area under the GIR curve was similar in elderly subjects vs. younger adults (mean ratio 1.01 [95% confidence interval 0.69-1.47]). Simulated SS pharmacodynamic profiles with once-daily IDegAsp showed a parallel upshift in GIR profiles vs. SD profiles. The shape of the IDegAsp pharmacodynamic profile was retained with twice-daily dosing under simulated SS conditions. IDegAsp was well tolerated. CONCLUSIONS: The distinct prandial and basal pharmacodynamics of IDegAsp observed in younger adults were preserved in elderly subjects with type 1 diabetes. The glucose-lowering effect of IDegAsp was similar in elderly subjects and younger adults with type 1 diabetes.

A feasibility study of a 3-day basal-bolus insulin delivery device in individuals with type 2 diabetes.

OBJECTIVE: This study tested the feasibility of transition from multiple daily injections (MDI) to a 3-day, basal-bolus insulin delivery device (PaQ) for type 2 diabetes (T2D). RESEARCH DESIGN AND METHODS: Twenty MDI-treated individuals with T2D with HbA(1c) ≤9% (75 mmol/mol) were enrolled in a single-center, single-arm pilot study, lasting three 2-week periods: baseline (MDI), transition to PaQ, and PaQ therapy. Feasibility of use, glycemic control, safety, and patient satisfaction were assessed. RESULTS: Nineteen participants transitioned to PaQ treatment and demonstrated competency in assembling, placing, and using the device. Self-monitored blood glucose and blinded continuous glucose-monitoring data showed glycemic control similar to MDI. Study participants reported high satisfaction and device acceptance. CONCLUSIONS: PaQ treatment is both feasible and acceptable in individuals with T2D. Transition from MDI is easy and safe. PaQ treatment might lead to better therapy adherence and improvements in glycemic control and clinical outcomes.

Periodic extraction of interstitial fluid from the site of subcutaneous insulin infusion for the measurement of glucose: a novel single-port technique for the treatment of type 1 diabetes patients.

BACKGROUND: Treatment of type 1 diabetes patients could be simplified if the site of subcutaneous insulin infusion could also be used for the measurement of glucose. This study aimed to assess the agreement between blood glucose concentrations and glucose levels in the interstitial fluid (ISF) that is extracted from the insulin infusion site during periodic short-term interruptions of continuous subcutaneous insulin infusion (CSII). SUBJECTS AND METHODS: A perforated cannula (24 gauge) was inserted into subcutaneous adipose tissue of C-peptide-negative type 1 diabetes subjects (n=13) and used alternately to infuse rapid-acting insulin (100 U/mL) and to extract ISF glucose during a fasting period and after ingestion of a standard oral glucose load (75 g). RESULTS: Although periodically interrupted for extracting glucose (every hour for approximately 10 min), insulin infusion with the cannula was adequate to achieve euglycemia during fasting and to restore euglycemia after glucose ingestion. Furthermore, the ISF-derived estimates of plasma glucose levels agreed well with plasma glucose concentrations. Correlation coefficient and median absolute relative difference values were found to be 0.95 and 8.0%, respectively. Error grid analysis showed 99.0% of all ISF glucose values within clinically acceptable Zones A and B (83.5% Zone A, 15.5% Zone B). CONCLUSIONS: Results show that ISF glucose concentrations measured at the insulin infusion site during periodic short-term interruptions of CSII closely reflect blood glucose levels, thus suggesting that glucose monitoring and insulin delivery may be performed alternately at the same tissue site. A single-port device of this type could be used to simplify and improve glucose management in diabetes.

Enhanced absorption of insulin aspart as the result of a dispersed injection strategy tested in a randomized trial in type 1 diabetic patients.

OBJECTIVE: We investigated the impact of two different injection strategies on the pharmacokinetics and pharmacodynamics of insulin aspart in vivo in an open-label, two-period crossover study and verified changes in the surface-to-volume ratio ex vivo. RESEARCH DESIGN AND METHODS: Before the clinical trial, insulin aspart was injected ex vivo into explanted human abdominal skin flaps. The surface-to-volume ratio of the subcutaneous insulin depot was assessed by microfocus computed tomography that compared 1 bolus of 18 IU with 9 dispersed boluses of 2 IU. These two injection strategies were then tested in vivo, in 12 C-peptide-negative type 1 diabetic patients in a euglycemic glucose clamp (glucose target 5.5 ± 1.1 mmol/L) for 8 h after the first insulin administration. RESULTS: The ex vivo experiment showed a 1.8-fold higher mean surface-to-volume ratio for the dispersed injection strategy. The maximum glucose infusion rates (GIR) were similar for the two strategies (10 ± 4 vs. 9 ± 4; P = 0.5); however, times to reach maximum GIR and 50% and 10% of the maximum GIR were significantly reduced by using the 9 × 2 IU strategy (68 ± 33 vs. 127 ± 93 min; P = 0.01; 38 ± 9 vs. 49 ± 16 min; P < 0.01; 23 ± 6 vs. 30 ± 10 min; P < 0.05). For 9 × 2 IU, the area under the GIR curve was greater during the first 60 min (219 ± 89 vs. 137 ± 75; P < 0.01) and halved until maximum GIR (242 ± 183 vs. 501 ± 396; P < 0.01); however, it was similar across the whole study period (1,361 ± 469 vs. 1,565 ± 527; P = 0.08). CONCLUSIONS: A dispersed insulin injection strategy enhanced the effect of a fast-acting insulin analog. The increased surface-to-volume ratio of the subcutaneous insulin depot can facilitate insulin absorption into the vascular system.

A comparison of the steady-state pharmacokinetic and pharmacodynamic profiles of 100 and 200 U/mL formulations of ultra-long-acting insulin degludec.

BACKGROUND AND OBJECTIVE: Insulin degludec (IDeg) is a new-generation basal insulin that forms soluble multi-hexamers upon subcutaneous injection, resulting in a depot from which IDeg monomers are slowly and continuously absorbed to provide an ultra-long action profile. This double-blind, crossover, randomized study compared the pharmacokinetic and pharmacodynamic properties between IDeg 100 U/mL (U100) and IDeg 200 U/mL (U200) under steady-state (SS) conditions in subjects with type 1 diabetes mellitus. METHODS: Participants (n = 33 adults) underwent 8-day treatment periods with 0.4 U/kg IDeg U100 and IDeg U200 given once daily with insulin aspart at mealtimes. On day 8, a 26-h euglycaemic glucose clamp (5.5 mmol/L) was performed. RESULTS: The concentration-time profiles of IDeg U100 and IDeg U200 were similar, and a post-hoc analysis showed bioequivalence between these formulations, as the 90 % confidence intervals (CIs) of the U200/U100 ratios for area under the steady-state serum IDeg concentration-time curve during a dosing interval (τ; 0-24 h) (AUCτ,SS,IDeg) (0.99 [0.91-1.07]) and maximum steady-state IDeg concentration during a dosing interval (τ) (C max,SS,IDeg) (0.93 [0.84-1.02]) were within the interval 0.80-1.25. Comparable glucose infusion rates (GIR) were observed for IDeg U100 and IDeg U200 (AUCτ,SS,GIR [mg/kg]: 2,255 vs. 2,123) and the mean ratio (95 % CI) of IDeg U200/U100 for the primary endpoint (AUCτ,SS,GIR) was 0.94 [0.86-1.03]. For both formulations, the glucose-lowering effect of IDeg was evenly distributed between the first and second 12 h post-dosing (U100: AUC12,SS,GIR/AUC24,SS,GIR = 48 %; U200: AUC12,SS,GIR/AUC24,SS,GIR = 46 %). Both formulations were well tolerated, and no safety events of significance were identified. CONCLUSION: IDeg U100 and U200 formulations are bioequivalent and have similar pharmacodynamic profiles at SS, implying that they can be used interchangeably in clinical practice.

Development and validation of a low cost blood filtration element separating plasma from undiluted whole blood.

Clinical point of care testing often needs plasma instead of whole blood. As centrifugation is labor intensive and not always accessible, filtration is a more appropriate separation technique. The complexity of whole blood is such that there is still no commercially available filtration system capable of separating small sample volumes (10-100 µl) at the point of care. The microfluidics research in blood filtration is very active but to date nobody has validated a low cost device that simultaneously filtrates small samples of whole blood and reproducibly recovers clinically relevant biomarkers, and all this in a limited amount of time with undiluted raw samples. In this paper, we show first that plasma filtration from undiluted whole blood is feasible and reproducible in a low-cost microfluidic device. This novel microfluidic blood filtration element (BFE) extracts 12 µl of plasma from 100 µl of whole blood in less than 10 min. Then, we demonstrate that our device is valid for clinical studies by measuring the adsorption of interleukins through our system. This adsorption is reproducible for interleukins IL6, IL8, and IL10 but not for TNFα. Hence, our BFE is valid for clinical diagnostics with simple calibration prior to performing any measurement.

Dermal PK/PD of a lipophilic topical drug in psoriatic patients by continuous intradermal membrane-free sampling.

BACKGROUND: Methodologies for continuous sampling of lipophilic drugs and high-molecular solutes in the dermis are currently lacking. We investigated the feasibility of sampling a lipophilic topical drug and the locally released biomarker in the dermis of non-lesional and lesional skin of psoriatic patients over 25h by means of membrane-free dermal open-flow microperfusion probes (dOFM) and novel wearable multi-channel pumps. METHODS: Nine psoriatic patients received a topical p-38 inhibitor (BCT194, 0.5% cream) on a lesional and a non-lesional application site once daily for 8 days. Multiple dOFM sampling was performed for 25 h from each site on day 1 and day 8. Patients were mobile as dOFM probes were operated by a novel light-weight push-pull pump. Ultrasound was used to verify intradermal probe placement, cap-LC-MS/MS for BCT194 and ELISA for TNFα analysis. RESULTS: dOFM was well tolerated and demonstrated significant drug concentrations in lesional as well as non-lesional skin after 8 days, but did not show significant differences between tissues. On day 8, TNFα release following probe insertion was significantly reduced compared to day 1. CONCLUSIONS: Novel membrane-free probes and wearable multi-channel pumps allowed prolonged intradermal PK/PD profiling of a lipophilic topical drug in psoriatic patients. This initial study shows that dOFM overcomes limitations of microdialysis sampling methodology, and it demonstrates the potential for PK/PD studies of topical products and formulations in a clinical setting.

A stepwise approach toward closed-loop blood glucose control for intensive care unit patients: results from a feasibility study in type 1 diabetic subjects using vascular microdialysis with infrared spectrometry and a model predictive control algorithm.

BACKGROUND: Glycemic control can reduce the mortality and morbidity of intensive care patients. The CLINICIP (closed-loop insulin infusion for critically ill patients) project aimed to develop a closed-loop control system for this patient group. Following a stepwise approach, we combined three independently tested subparts to form a semiautomatic closed-loop system and evaluated it with respect to safety and performance aspects by testing it in subjects with type 1 diabetes mellitus (T1DM) in a first feasibility trial. METHODS: Vascular microdialysis, a multianalyte infrared spectroscopic glucose sensor, and a standard insulin infusion pump controlled by an adaptive model predictive control (MPC) algorithm were combined to form a closed-loop device, which was evaluated in four T1DM subjects during 30-hour feasibility studies. The aim was to maintain blood glucose concentration in the target range between 80 and 110 mg/dl. RESULTS: Mean plasma glucose concentration was 110.5 ± 29.7 mg/dl. The MPC managed to establish normoglycemia within 105 ± 78 minutes after trial start and managed to maintain glucose concentration within the target range for 47% of the time. The hyperglycemic index averaged to 11.9 ± 5.3 mg/dl. CONCLUSION: Data of the feasibility trial illustrate the device being effective in controlling glycemia in T1DM subjects. However, the monitoring part of the loop must be improved with respect to accuracy and precision before testing the system in the target population.

Glucose levels at the site of subcutaneous insulin administration and their relationship to plasma levels.

OBJECTIVE: To examine insulin's effect on the tissue glucose concentration at the site of subcutaneous insulin administration. RESEARCH DESIGN AND METHODS: A CMA-60 microdialysis (MD) catheter and a 24-gauge microperfusion (MP) catheter were inserted into the subcutaneous adipose tissue of fasting, healthy subjects (n = 5). Both catheters were perfused with regular human insulin (100 units/ml) over a 6-h period and used for glucose sampling and simultaneous administration of insulin at sequential rates of 0.33, 0.66, and 1.00 units/h (each rate was used for 2 h). Before and after the insulin delivery period, both catheters were perfused with an insulin-free solution (5% mannitol) for 2 h and used for glucose sampling only. Blood plasma glucose was clamped at euglycemic levels during insulin delivery. RESULTS: Start of insulin delivery with MD and MP catheters resulted in a decline of the tissue glucose concentration and the tissue-to-plasma glucose ratio (TPR) for approximately 60 min (P < 0.05). However, during the rest of the 6-h period of variable insulin delivery, tissue glucose concentration paralleled the plasma glucose concentration, and the TPR for MD and MP catheters remained unchanged at 83.2 +/- 3.1 and 77.1 +/- 4.8%, respectively. After subsequent switch to insulin-free perfusate, tissue glucose concentration and TPR increased slowly and reattained preinsulin delivery levels by the end of the experiments. CONCLUSIONS: The results show the attainment of a stable TPR value at the site of insulin administration, thus indicating that insulin delivery and glucose sensing may be performed simultaneously at the same adipose tissue site.

Use of the site of subcutaneous insulin administration for the measurement of glucose in patients with type 1 diabetes.

OBJECTIVE To simplify and improve the treatment of patients with type 1 diabetes, we ascertained whether the site of subcutaneous insulin infusion can be used for the measurement of glucose. RESEARCH DESIGN AND METHODS Three special indwelling catheters (24-gauge microperfusion [MP] catheters) were inserted into the subcutaneous adipose tissue of subjects with type 1 diabetes (n = 10; all C-peptide negative). One MP catheter was perfused with short-acting insulin (100 units/ml, Aspart) and used for insulin delivery and simultaneous glucose sampling during an overnight fast and after ingestion of a standard glucose load (75 g). As controls, the further two MP catheters were perfused with an insulin-free solution (5% mannitol) and used for glucose sampling only. Plasma glucose was measured frequently at the bedside. RESULTS Insulin delivery with the MP catheter was adequate to achieve and maintain normoglycemia during fasting and after glucose ingestion. Tissue glucose concentrations derived with the insulin-perfused catheter agreed well with plasma glucose levels. Median correlation coefficient and median absolute relative difference values were found to be 0.93 (interquartile range 0.91-0.97) and 10.9%, respectively. Error grid analysis indicated that the percentage number of tissue values falling in the clinically acceptable range is 99.6%. Comparable analysis results were obtained for the two mannitol-perfused catheters. CONCLUSIONS Our data suggest that estimation of plasma glucose concentrations from the glucose levels directly observed at the site of subcutaneous insulin infusion is feasible and its quality is comparable to that of estimating plasma glucose concentrations from glucose levels measured in insulin-unexposed subcutaneous tissue.