TRPC6 inhibitor (BI 764198) to reduce risk and severity of ARDS due to COVID-19: a phase II randomised controlled trial

BACKGROUND

Despite the availability of COVID-19 vaccinations, there remains a need to investigate treatments to reduce the risk or severity of potentially fatal complications of COVID-19, such as acute respiratory distress syndrome (ARDS). This study evaluated the efficacy and safety of the transient receptor potential channel C6 (TRPC6) inhibitor, BI 764198, in reducing the risk and/or severity of ARDS in patients hospitalised for COVID-19 and requiring non-invasive, supplemental oxygen support (oxygen by mask or nasal prongs, oxygen by non-invasive ventilation or high-flow nasal oxygen).

METHODS

Multicentre, double-blind, randomised phase II trial comparing once-daily oral BI 764198 (n=65) with placebo (n=64) for 28 days (+2-month follow-up).

PRIMARY ENDPOINT

proportion of patients alive and free of mechanical ventilation at day 29. Secondary endpoints: proportion of patients alive and discharged without oxygen (day 29); occurrence of either in-hospital mortality, intensive care unit admission or mechanical ventilation (day 29); time to first response (clinical improvement/recovery); ventilator-free days (day 29); and mortality (days 15, 29, 60 and 90).

RESULTS

No difference was observed for the primary endpoint: BI 764198 (83.1%) versus placebo (87.5%) (estimated risk difference -5.39%; 95% CI -16.08 to 5.30; p=0.323). For secondary endpoints, a longer time to first response (rate ratio 0.67; 95% CI 0.46 to 0.99; p=0.045) and longer hospitalisation (+3.41 days; 95% CI 0.49 to 6.34; p=0.023) for BI 764198 versus placebo was observed; no other significant differences were observed. On-treatment adverse events were similar between trial arms and more fatal events were reported for BI 764198 (n=7) versus placebo (n=2). Treatment was stopped early based on an interim observation of a lack of efficacy and an imbalance of fatal events (Data Monitoring Committee recommendation).

CONCLUSIONS

TRPC6 inhibition was not effective in reducing the risk and/or severity of ARDS in patients with COVID-19 requiring non-invasive, supplemental oxygen support.

TRIAL REGISTRATION NUMBER

NCT04604184.

Patient preferences for newer oral therapies in type 2 diabetes

BACKGROUND

We aimed to evaluate patient preferences towards three oral antihyperglycaemic therapies using conjoint analysis to determine which attributes may influence use.

METHODS

We used an online survey, completed by 553 US respondents with type 2 diabetes mellitus (T2DM; mean age 64 ± 9 years; 55% had cardiovascular [CV] risk; 27% had CV disease), to present hypothetical, blinded, pairwise, drug profile comparison choices, between different benefit/risk attributes and effect ranges. Attributes were derived from phase 3 trials for empagliflozin 25 mg (SGLT2 inhibitor), oral semaglutide 14 mg (GLP-1 receptor agonist) and sitagliptin 100 mg (DPP-4 inhibitor). Predicted therapy preference outcomes and relative importance of each attribute were calculated (presented as a percentage).

RESULTS

Preference score was highest for the profile matching empagliflozin (56%), versus sitagliptin (38%; z-test, P < 0.001) and oral semaglutide (6%, z-test, P < 0.001). Results were overall consistent in subgroup analyses. Genital infection risk was the most important attribute (relative score: 19% [z-test, P = 0.077]). Other important attributes were fasting requirements (15%), weight reduction (15%), risk of vomiting (14%), CV benefit (12%), and risk of nausea (11%). HbA1c reduction (8%) and ability to take medication with other drugs (6%) were considered less important. While blinded to drug name/dose, respondents chose a drug profile similar to empagliflozin (41%) versus sitagliptin (31%), oral semaglutide (11%), or 'none of the options' (17%).

CONCLUSION

While the drug profile comparable to empagliflozin was preferred, CV benefit was not the top patient priority. A shared physician-patient decision model and increased patient education are needed to ensure optimal use of guideline-directed T2DM therapies.

Renal and Vascular Effects of Combined SGLT2 and Angiotensin-Converting Enzyme Inhibition

BACKGROUND

The cardiorenal effects of sodium-glucose cotransporter 2 inhibition (empagliflozin 25 mg QD) combined with angiotensin-converting enzyme inhibition (ramipril 10 mg QD) were assessed in this mechanistic study in patients with type 1 diabetes with potential renal hyperfiltration.

METHODS

Thirty patients (out of 31 randomized) completed this double-blind, placebo-controlled, crossover trial. Recruitment was stopped early because of an unexpectedly low proportion of patients with hyperfiltration. Measurements were obtained after each of the 6 treatment phases over 19 weeks: (1) baseline without treatment, (2) 4-week run-in with ramipril treatment alone, (3) 4-week combined empagliflozin-ramipril treatment, (4) a 4-week washout, (5) 4-week combined placebo-ramipril treatment, and (6) 1-week follow-up. The primary end point was glomerular filtration rate (GFR) after combination treatment with empagliflozin-ramipril compared with placebo-ramipril. GFR was corrected for ramipril treatment alone before randomization. At the end of study phase, the following outcomes were measured under clamped euglycemia (4 to 6 mmol/L): inulin (GFR) and para-aminohippurate (effective renal plasma flow) clearances, tubular sodium handling, ambulatory blood pressure, arterial stiffness, heart rate variability, noninvasive cardiac output monitoring, plasma and urine biochemistry, markers of the renin-angiotensin-aldosterone system, and oxidative stress.

RESULTS

Combination treatment with empagliflozin-ramipril resulted in an 8 mL/min/1.73 m² lower GFR compared with placebo-ramipril treatment (P=0.0061) without significant changes to effective renal plasma flow. GFR decrease was accompanied by a 21.3 mL/min lower absolute proximal fluid reabsorption rate (P=0.0092), a 3.1 mmol/min lower absolute proximal sodium reabsorption rate (P=0.0056), and a 194 ng/mmol creatinine lower urinary 8-isoprostane level (P=0.0084) relative to placebo-ramipril combination treatment. Sodium-glucose cotransporter 2 inhibitor/angiotensin-converting enzyme inhibitor combination treatment resulted in additive blood pressure-lowering effects (clinic systolic blood pressure lower by 4 mm Hg [P=0.0112]; diastolic blood pressure lower by 3 mm Hg [P=0.0032]) in conjunction with a 94.5 dynes × sex/cm⁵ lower total peripheral resistance (P=0.0368). There were no significant changes observed to ambulatory blood pressure, arterial stiffness, heart rate variability, or cardiac output with the addition of empagliflozin.

CONCLUSIONS

Adding sodium-glucose cotransporter 2 inhibitor treatment to angiotensin-converting enzyme inhibitor resulted in an expected GFR dip, suppression of oxidative stress markers, additive declines in blood pressure and total peripheral resistance. These changes are consistent with a protective physiologic profile characterized by the lowering of intraglomerular pressure and related cardiorenal risk when adding a sodium-glucose cotransporter 2 inhibitor to conservative therapy.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT02632747.

A Model-Informed Drug Development (MIDD) Approach for a Low Dose of Empagliflozin in Patients with Type 1 Diabetes

In clinical trials, sodium-glucose co-transporter (SGLT) inhibitor use as adjunct to insulin therapy in type 1 diabetes (T1D) provides glucometabolic benefits while diabetic ketoacidosis risk is increased. The SGLT2 inhibitor empagliflozin was evaluated in two phase III trials: EASE-2 and EASE-3. A low, 2.5-mg dose was included in EASE-3 only. As the efficacy of higher empagliflozin doses (i.e., 10 and 25 mg) in T1D has been established in EASE-2 and EASE-3, a modeling and simulation approach was used to generate additional supportive evidence on efficacy for the 2.5-mg dose. We present the methodology behind the development and validation of two modeling and simulation frameworks: M-EASE-1, a semi-mechanistic model integrating information on insulin, glucose, and glycated hemoglobin; and M-EASE-2, a descriptive model informed by prior information. Both models were developed independently of data from EASE-3. Simulations based on these models assessed efficacy in untested clinical trial scenarios. In this manner, the models provide supportive evidence for efficacy of low-dose empagliflozin 2.5 mg in patients with T1D, illustrating how pharmacometric analyses can support efficacy assessments in the context of limited data.

Low-dose empagliflozin as adjunct-to-insulin therapy in type 1 diabetes: A valid modelling and simulation analysis to confirm efficacy

AIM

To confirm the observed reduction in HbA1c for the 2.5 mg dose in EASE-3 by modelling and simulation analyses.

MATERIALS AND METHODS

Independent of data from EASE-3 that tested 2.5 mg, we simulated the effect of a 2.5 mg dose through patient-level, exposure-response modelling in the EASE-2 clinical study. A primary semi-mechanistic model evaluated efficacy considering clinical insulin dose adjustments made after treatment initiation that potentially limited HbA1c reductions. The model was informed by pharmacokinetic, insulin dose, mean daily glucose and HbA1c data, and was verified by comparing the simulations with the observed HbA1c change in EASE-3. One of two empagliflozin phase 3 trials in type 1 diabetes (EASE-3 but not EASE-2) included a lower 2.5 mg dose. A placebo-corrected HbA1c reduction of 0.28% was demonstrated without the increased risk of diabetic ketoacidosis observed at higher doses (10 mg and 25 mg). Since only one trial included the lower dose, we aimed to confirm the observed reduction in HbA1c for the 2.5 mg dose by modelling and simulation analyses.

RESULTS

The simulated 26-week mean HbA1c change was -0.41% without insulin dose adjustment and -0.29% at 26 weeks with insulin dose adjustment. A simplified (descriptive) model excluding insulin dose and mean daily glucose confirmed the -0.29% HbA1c change that would have been observed had the EASE-2 population received a 2.5 mg dose for 26/52 weeks.

CONCLUSIONS

The HbA1c benefit of low-dose empagliflozin directly observed in the EASE-3 trial was confirmed by two modelling and simulation approaches.

Exploring Patient Preferences for Adjunct-to-Insulin Therapy in Type 1 Diabetes

OBJECTIVE

While sodium-glucose cotransporter inhibitor (SGLTi) therapy has been evaluated in type 1 diabetes (T1D) trials, patient reactions to benefits and risks are unknown. Using established methodology, we evaluated patient preferences for different adjunct-to-insulin therapy options in T1D.

RESEARCH DESIGN AND METHODS

An online survey, completed by 701 respondents with T1D (231 U.S., 242 Canada, and 228 Germany), used conjoint analysis to present six hypothetical, masked, pairwise drug profile choices composed of different benefit-risk attributes and effect ranges. Data used in analyses were derived from actual phase 3 trials of a low-dose SGLTi (comparable to oral empagliflozin 2.5 mg q.d.), a high-dose SGLTi (comparable to oral sotagliflozin 400 mg q.d.), and an available adjunct-to-insulin therapy (comparable to subcutaneous pramlintide 60 μg t.i.d.).

RESULTS

Conjoint analysis identified diabetic ketoacidosis risk as most important to patients (23% relative score; z test, P < 0.05); ranked second were HbA_1c reduction (14%), risk of severe hypoglycemia (13%), oral versus injectable treatment (12%), and risk of genital infection (12%). Next was risk of nausea (11%), followed by weight reduction (8%) and the risk of diarrhea (7%). A low-dose SGLTi drug profile was identified by conjoint analysis as the top patient preference (83% of participants; z test, P < 0.05) versus high-dose SGLTi (8%) or pramlintide (9%). Separate from conjoint analysis, when respondents were asked to choose their preferred adjunct-to-insulin therapy (masked to drug name/dose), 69%, 17%, 6%, and 9% of respondents chose low-dose SGLTi, high-dose SGLTi, pramlintide, and insulin therapy alone, respectively.

CONCLUSIONS

Low-dose SGLTi profile was the favored adjunct-to-insulin therapy by persons with T1D.

Empagliflozin as Adjunctive to Insulin Therapy in Type 1 Diabetes: The EASE Trials

OBJECTIVE

To evaluate the safety and efficacy of empagliflozin 10- and 25-mg doses plus a unique lower dose (2.5 mg) as adjunct to intensified insulin in patients with type 1 diabetes (T1D).

RESEARCH DESIGN AND METHODS

The EASE (Empagliflozin as Adjunctive to inSulin thErapy) program (N = 1,707) included two double-blind, placebo-controlled phase 3 trials: EASE-2 with empagliflozin 10 mg (n = 243), 25 mg (n = 244), and placebo (n = 243), 52-week treatment; and EASE-3 with empagliflozin 2.5 mg (n = 241), 10 mg (n = 248), 25 mg (n = 245), and placebo (n = 241), 26-week treatment. Together they evaluated empagliflozin 10 mg and 25 mg, doses currently approved in treatment of type 2 diabetes, and additionally 2.5 mg on 26-week change in glycated hemoglobin (primary end point) and weight, glucose time-in-range (>70 to ≤180 mg/dL), insulin dose, blood pressure, and hypoglycemia.

RESULTS

The observed largest mean placebo-subtracted glycated hemoglobin reductions were -0.28% (95% CI -0.42, -0.15) for 2.5 mg, -0.54% (-0.65, -0.42) for 10 mg, and -0.53% (-0.65, -0.42) for 25 mg (all P < 0.0001). Empagliflozin 2.5/10/25 mg doses, respectively, reduced mean weight by -1.8/-3.0/-3.4 kg (all P < 0.0001); increased glucose time-in-range by +1.0/+2.9/+3.1 h/day (P < 0.0001 for 10 and 25 mg); lowered total daily insulin dose by -6.4/-13.3/-12.7% (all P < 0.0001); and decreased systolic blood pressure by -2.1/-3.9/-3.7 mmHg (all P < 0.05). Genital infections occurred more frequently on empagliflozin. Adjudicated diabetic ketoacidosis occurred more with empagliflozin 10 mg (4.3%) and 25 mg (3.3%) but was comparable between empagliflozin 2.5 mg (0.8%) and placebo (1.2%). Severe hypoglycemia was rare and frequency was similar between empagliflozin and placebo.

CONCLUSIONS

Empagliflozin improved glycemic control and weight in T1D without increasing hypoglycemia. Ketoacidosis rate was comparable between empagliflozin 2.5 mg and placebo but increased with 10 mg and 25 mg. Ketone monitoring for early ketoacidosis detection and intervention and lower empagliflozin doses may help to reduce this risk.

Empagliflozin as adjunct to insulin in Japanese participants with type 1 diabetes: Results of a 4-week, double-blind, randomized, placebo-controlled phase 2 trial

AIMS

This phase 2, double-blind, randomized, placebo-controlled trial (ClinicalTrials.gov NCT02702011) with 4 sites in Japan investigated the pharmacodynamics (PD), pharmacokinetics (PK) and safety profile of empagliflozin in Japanese participants with type 1 diabetes mellitus (T1DM) as adjunctive therapy to insulin.

MATERIALS AND METHODS

Participants using multiple daily injections of insulin for ≥12 months, with HbA1c of 7.5%-10.0%, entered a 2-week, open-label, placebo run-in period, followed by a 4-week, double-blind period during which participants were randomized 1:1:1:1 to receive empagliflozin 2.5 mg (n = 13), empagliflozin 10 mg (n = 12), empagliflozin 25 mg (n = 12) or placebo (n = 11). The primary objective was to assess the effect of empagliflozin vs placebo on urinary glucose excretion (UGE) after 7 days of treatment.

RESULTS

PD: Empagliflozin resulted in a dose-dependent significant increase in 24-hour UGE compared with placebo (UGE placebo-corrected mean [95% confidence interval] change from baseline: 2.5 mg, 65.10 [43.29, 86.90] g/24 h; 10 mg, 81.19 [58.80, 103.58] g/24 h; 25 mg, 98.11 [75.91, 120.31] g/24 h). After 4 weeks of treatment, UGE increase was associated with improved glycaemic control, reduced body weight and decreased insulin needs. Empagliflozin treatment also resulted in dose-dependent increases in serum ketone bodies and free fatty acids. PK: Plasma empagliflozin levels increased in a dose-dependent manner and peaked at 1.5 hours. In this short study, empagliflozin was well tolerated, with no increase in rate of hypoglycaemia and no diabetic ketoacidosis events reported.

CONCLUSIONS

Based on this short-duration phase 2 study, the PK/PD profile of empagliflozin in Japanese participants with T1DM is comparable to that of non-Japanese participants.

Population Pharmacokinetic- Pharmacodynamic Analysis to Characterize the Effect of Empagliflozin on Renal Glucose Threshold in Patients With Type 1 Diabetes Mellitus

Sodium glucose cotransporter 2 inhibitors increase urinary glucose excretion (UGE) by lowering the renal threshold for glucose (RT_G ). We aimed to quantify the effect of the sodium glucose cotransporter inhibitor empagliflozin on renal glucose reabsorption in patients with type 1 diabetes mellitus (T1DM) using a mechanistic population pharmacokinetic-pharmacodynamic (PK-PD) model and to compare results with analyses in patients with type 2 diabetes mellitus (T2DM). The PK-PD model was developed using data from a randomized phase 2 study in which patients with T1DM received oral once-daily empagliflozin 2.5 mg, empagliflozin 10 mg, empagliflozin 25 mg, or placebo as an adjunct to insulin. The model assumed that UGE was dependent on plasma glucose and renal function and that empagliflozin lowered RT_G . The final model was evaluated using visual predictive checks and found to be consistent with observed data. Calculated RT_G with placebo was 181 mg/dL, and with empagliflozin (steady state) 1 mg and 2.5 mg was 53.4 mg/dL and 12.5 mg/dL, respectively. Empagliflozin 10 mg and 25 mg yielded negative RT_G values, implying RT_G was reduced to a negligible value. Although estimated PK-PD parameters were generally comparable between patients with T1DM and patients with T2DM, slight differences were evident, leading to lower RT_G and higher UGE in patients with T1DM compared with patients with T2DM. In conclusion, the model provided a reasonable description of UGE in response to administration of empagliflozin and placebo in patients with T1DM.

Incidence and prevalence of diabetic ketoacidosis (DKA) among adults with type 1 diabetes mellitus (T1D): a systematic literature review

OBJECTIVES

To summarise incidence and prevalence of diabetic ketoacidosis (DKA) in adults with type 1 diabetes (T1D) for the overall patient population and different subgroups (age, sex, geographical region, ethnicity and type of insulin administration).

DESIGN

Systematic literature review (SLR).

DATA SOURCES

Medline (via PubMed) and Embase (1 January 2000 to 23 June 2016).

STUDY SELECTION

Peer-reviewed observational studies with reported data on the incidence or prevalence of DKA in T1D adults were included. A single reviewer completed the study screening and selection process and a second reviewer performed an additional screening of approximately 20% of the publications; two reviewers independently conducted the quality assessment; the results were narratively synthesised.

RESULTS

Out of 1082 articles, 19 met the inclusion and exclusion criteria, with two additional studies identified that did not specify the patient age range and are therefore not included in the SLR. Overall, eight studies reported incidence with a range of 0-56 per 1000 person-years (PYs), with one outlying study reporting an incidence of 263 per 1000 PYs. Eleven studies reported prevalence with a range of 0-128 per 1000 people. Prevalence of DKA decreased with increasing age. Subgroup analyses were performed using data from no more than two studies per subgroup. There was a higher prevalence of DKA reported in women, non-whites and patients treated with insulin injections compared with men, whites and patients using continuous subcutaneous insulin infusion pumps, respectively.

CONCLUSIONS

To our knowledge, this is the first SLR on the epidemiology of DKA in T1D adults. Despite an increasing prevalence of T1D in recent years, DKA in adults has been poorly characterised. In an era when the benefit-risk profiles of new antidiabetic therapies are being evaluated, including the potential risk of DKA, there is a clear need to better elucidate the expected rate of DKA among T1D adults.

Glucose Exposure and Variability with Empagliflozin as Adjunct to Insulin in Patients with Type 1 Diabetes: Continuous Glucose Monitoring Data from a 4-Week, Randomized, Placebo-Controlled Trial (EASE-1)

BACKGROUND

We evaluated the effect of empagliflozin as adjunct to insulin on 24-h glucose exposure and variability in patients with type 1 diabetes.

METHODS

Patients (N = 75) with HbA_1c ≥7.5% to ≤10.5% were randomized to receive empagliflozin 2.5 mg, empagliflozin 10 mg, empagliflozin 25 mg, or placebo once daily as adjunct to insulin for 4 weeks. Insulin dose was to be kept as stable as possible during week 1 of treatment and was freely adjustable thereafter. Markers of glucose exposure and variability were assessed from 7-day blinded continuous glucose monitoring intervals. This study is completed ( ClinicalTrials.gov NCT01969747).

RESULTS

Empagliflozin reduced hourly mean glucose area under the median curve over 24 h versus placebo within week 1 (adjusted mean differences: -12.2 mg/dL·h [95% confidence interval -23.9 to -0.5], -30.2 mg/dL·h [-42.2 to -18.2], and -33.0 mg/dL·h [-44.8 to -21.1] with empagliflozin 2.5, 10, and 25 mg, respectively; all P < 0.05) and increased time in glucose target range (>70 to ≤180 mg/dL). Results were sustained to week 4 with empagliflozin 25 mg. All empagliflozin doses significantly reduced glucose variability (interquartile range and mean amplitude of glucose excursions) versus placebo at weeks 1 and 4. Except for small increases in hours per day with glucose ≤70 mg/dL during the stable insulin period, empagliflozin did not increase time in hypoglycemia compared with placebo.

CONCLUSIONS

In patients with type 1 diabetes, empagliflozin as adjunct to insulin decreased glucose exposure and variability and increased time in glucose target range.

Empagliflozin as adjunct to insulin in patients with type 1 diabetes: a 4-week, randomized, placebo-controlled trial (EASE-1)

AIMS

To investigate the pharmacodynamics, efficacy and safety of empagliflozin as adjunct to insulin in patients with type 1 diabetes.

METHODS

A total of 75 patients with glycated haemoglobin (HbA1c) concentrations of ≥7.5 to ≤10.5% (≥58 to ≤91 mmol/mol) were randomized to receive once-daily empagliflozin 2.5 mg, empagliflozin 10 mg, empagliflozin 25 mg, or placebo as adjunct to insulin for 28 days. Insulin dose was to be kept as stable as possible for 7 days then adjusted, at the investigator's discretion, to achieve optimum glycaemic control. The primary exploratory endpoint was change from baseline in 24-h urinary glucose excretion (UGE) on day 7.

RESULTS

Empagliflozin significantly increased 24-h UGE versus placebo on days 7 and 28. On day 28, adjusted mean differences with empagliflozin versus placebo in changes from baseline in: HbA1c were -0.35 to -0.49% (-3.8 to -5.4 mmol/mol; all p < 0.05 vs. placebo); total daily insulin dose -0.07 to -0.09 U/kg (all p<0.05 vs placebo); and weight were -1.5 to -1.9 kg (all p < 0.001 vs. placebo). In the placebo, empagliflozin 2.5, 10 and 25 mg groups, respectively, adverse events were reported in 94.7, 89.5, 78.9 and 100.0% of patients, and the rate of symptomatic hypoglycaemic episodes with glucose ≤3.0 mmol/l not requiring assistance was 1.0, 0.4, 0.5 and 0.8 episodes per 30 days.

CONCLUSIONS

In patients with type 1 diabetes, empagliflozin for 28 days as adjunct to insulin increased UGE, improved HbA1c and reduced weight with lower insulin doses compared with placebo and without increasing hypoglycaemia.

Sodium-glucose cotransporter 2 inhibition and glycemic control in type 1 diabetes: results of an 8-week open-label proof-of-concept trial

OBJECTIVE

Adjunctive-to-insulin therapy with sodium-glucose cotransporter 2 (SGLT2) inhibition may improve glycemic control in type 1 diabetes (T1D).

RESEARCH DESIGN AND METHODS

We evaluated the glycemic efficacy and safety of empagliflozin 25 mg daily in 40 patients treated for 8 weeks in a single-arm open-label proof-of-concept trial (NCT01392560).

RESULTS

Mean A1C decreased from 8.0 ± 0.9% (64 ± 10 mmol/mol) to 7.6 ± 0.9% (60 ± 10 mmol/mol) (P < 0.0001), fasting glucose from 9.0 ± 4.3 to 7.0 ± 3.2 mmol/L (P = 0.008), symptomatic hypoglycemia (<3.0 mmol/L) from 0.12 to 0.04 events per patient per day (P = 0.0004), and daily insulin dose from 54.7 ± 20.4 to 45.8 ± 18.8 units/day (P < 0.0001). Mean urinary excretion of glucose increased from 19 ± 19 to 134 ± 61 g/day (P < 0.0001). Weight decreased from 72.6 ± 12.7 to 70.0 ± 12.3 kg (P < 0.0001), and waist circumference decreased from 82.9 ± 8.7 to 79.1 ± 8.0 cm (P < 0.0001).

CONCLUSIONS

This proof-of-concept study strongly supports a randomized clinical trial of adjunctive-to-insulin empagliflozin in patients with T1D.

The effect of empagliflozin on arterial stiffness and heart rate variability in subjects with uncomplicated type 1 diabetes mellitus

Background

Individuals with type 1 diabetes mellitus are at high risk for the development of hypertension, contributing to cardiovascular complications. Hyperglycaemia-mediated neurohormonal activation increases arterial stiffness, and is an important contributing factor for hypertension. Since the sodium glucose cotransport-2 (SGLT2) inhibitor empagliflozin lowers blood pressure and HbA1c in type 1 diabetes mellitus, we hypothesized that this agent would also reduce arterial stiffness and markers of sympathetic nervous system activity.

Methods

Blood pressure, arterial stiffness, heart rate variability (HRV) and circulating adrenergic mediators were measured during clamped euglycaemia (blood glucose 4–6 mmol/L) and hyperglycaemia (blood glucose 9–11 mmol/L) in 40 normotensive type 1 diabetes mellitus patients. Studies were repeated after 8 weeks of empagliflozin (25 mg once daily).

Results

In response to empagliflozin during clamped euglycaemia, systolic blood pressure (111 ± 9 to 109 ± 9 mmHg, p = 0.02) and augmentation indices at the radial (-52% ± 16 to -57% ± 17, p = 0.0001), carotid (+1.3 ± 1 7.0 to -5.7 ± 17.0%, p < 0.0001) and aortic positions (+0.1 ± 13.4 to -6.2 ± 14.3%, p < 0.0001) declined. Similar effects on arterial stiffness were observed during clamped hyperglycaemia without changing blood pressure under this condition. Carotid-radial pulse wave velocity decreased significantly under both glycemic conditions (p ≤ 0.0001), while declines in carotid-femoral pulse wave velocity were only significant during clamped hyperglycaemia (5.7 ± 1.1 to 5.2 ± 0.9 m/s, p = 0.0017). HRV, plasma noradrenalin and adrenaline remained unchanged under both clamped euglycemic and hyperglycemic conditions.

Conclusions

Empagliflozin is associated with a decline in arterial stiffness in young type 1 diabetes mellitus subjects. The underlying mechanisms may relate to pleiotropic actions of SGLT2 inhibition, including glucose lowering, antihypertensive and weight reduction effects.

Trial registration

Clinical trial registration: NCT01392560

Renal hemodynamic effect of sodium-glucose cotransporter 2 inhibition in patients with type 1 diabetes mellitus

BACKGROUND

The primary objective of this mechanistic open-label, stratified clinical trial was to determine the effect of 8 weeks' sodium glucose cotransporter 2 inhibition with empagliflozin 25 mg QD on renal hyperfiltration in subjects with type 1 diabetes mellitus (T1D).

METHODS AND RESULTS

Inulin (glomerular filtration rate; GFR) and paraaminohippurate (effective renal plasma flow) clearances were measured in individuals stratified based on having hyperfiltration (T1D-H, GFR ≥ 135 mL/min/1.73m(2), n=27) or normal GFR (T1D-N, GFR 90-134 mL/min/1.73m(2), n=13) at baseline. Renal function and circulating levels of renin-angiotensin-aldosterone system mediators and NO were measured under clamped euglycemic (4-6 mmol/L) and hyperglycemic (9-11 mmol/L) conditions at baseline and end of treatment. During clamped euglycemia, hyperfiltration was attenuated by -33 mL/min/1.73m(2) with empagliflozin in T1D-H, (GFR 172±23-139±25 mL/min/1.73 m(2), P<0.01). This effect was accompanied by declines in plasma NO and effective renal plasma flow and an increase in renal vascular resistance (all P<0.01). Similar significant effects on GFR and renal function parameters were observed during clamped hyperglycemia. In T1D-N, GFR, other renal function parameters, and plasma NO were not altered by empagliflozin. Empagliflozin reduced hemoglobin A1c significantly in both groups, despite lower insulin doses in each group (P≤0.04).

CONCLUSIONS

In conclusion, short-term treatment with the sodium glucose cotransporter 2 inhibitor empagliflozin attenuated renal hyperfiltration in subjects with T1D, likely by affecting tubular-glomerular feedback mechanisms.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT01392560.

Hypoxic switch in mitochondrial myeloid cell leukemia factor-1/Mtd apoptotic rheostat contributes to human trophoblast cell death in preeclampsia

Preeclampsia, a disorder of pregnancy, is characterized by increased trophoblast cell death and altered trophoblast-mediated remodeling of myometrial spiral arteries resulting in reduced uteroplacental perfusion. Mitochondria-associated Bcl-2 family members are important regulators of programed cell death. The mechanism whereby hypoxia alters the mitochondrial apoptotic rheostat is essential to our understanding of placental disease. Herein, myeloid cell leukemia factor-1 (Mcl-1) isoform expression was examined in physiological/pathological models of placental hypoxia. Preeclamptic placentae were characterized by caspase-dependent cleavage of death-suppressing Mcl-1L and switch toward cell death-inducing Mcl-1S. In vitro, Mcl-1L cleavage was induced by hypoxia-reoxygenation in villous explants, whereas Mcl-1L overexpression under hypoxia-reoxygenation rescued trophoblast cells from undergoing apoptosis. Cleavage was mediated by caspase-3/-7 because pharmacological caspase inhibition prevented this process. Altitude-induced chronic hypoxia was characterized by expression of Mcl-1L; resulting in a reduction of apoptotic markers (cleaved caspase-3/-8 and p85 poly-ADP-ribose polymerase). Moreover, in both physiological (explants and high altitude) and pathological (preeclampsia) placental hypoxia, decreased trophoblast syncytin expression was observed. Hence, although both pathological and physiological placental hypoxia are associated with slowed trophoblast differentiation, trophoblast apoptosis is only up-regulated in preeclampsia, because of a hypoxia-reoxygenation-induced switch in generation of proapoptotic Mcl-1 isoforms.

Oxygen regulation of macrophage migration inhibitory factor in human placenta

Macrophage migration inhibitory factor (MIF) is an important proinflammatory cytokine involved in regulation of macrophage function. In addition, MIF may also play a role in murine and human reproduction. Although both first trimester trophoblast and decidua express MIF, the regulation and functional significance of this cytokine during human placental development remains unclear. We assessed MIF expression throughout normal human placental development, as well as in in vitro (chorionic villous explants) and in vivo (high altitude placentae) models of human placental hypoxia. Dimethyloxalylglycine (DMOG), which stabilizes hypoxia inducible factor-1 under normoxic conditions, was also used to mimic the effects of hypoxia on MIF expression. Quantitative real-time PCR and Western blot analysis showed high MIF protein and mRNA expression at 7-10 wk and lower levels at 11-12 wk until term. Exposure of villous explants to 3% O(2) resulted in increased MIF expression and secretion relative to standard conditions (20% O(2)). DMOG treatment under 20% O(2) increased MIF expression. In situ hybridization and immunohistochemistry showed elevated MIF expression in low oxygen-induced extravillous trophoblast cells. Finally, a significant increase in MIF transcript was observed in placental tissues from high-altitude pregnancies. Hence, three experimental models of placental hypoxia (early gestation, DMOG treatment, and high altitude) converge in stimulating increased MIF, supporting the conclusion that placental-derived MIF is an oxygen-responsive cytokine highly expressed in physiological in vivo and in in vitro low oxygen conditions.

Increased expression of sFlt-1 in in vivo and in vitro models of human placental hypoxia is mediated by HIF-1

Elevated expression of soluble vascular endothelial growth factor receptor-1 (sFlt-1) in preeclampsia plays a major role in the pathogenesis of this serious disorder of human pregnancy. Although reduced placental oxygenation is thought to be involved in the pathogenesis of preeclampsia, it is unclear how oxygen regulates placental sFlt-1 expression. The aims herein were to investigate sFlt-1 expression in in vivo and in vitro physiological and pathological models of human placental hypoxia and to understand the role of hypoxia inducible factor-1 (HIF-1) in regulating the expression of this molecule. sFlt-1 expression in placental villi was significantly increased under physiological low oxygen conditions in early first-trimester and in high-altitude placentae, as well as in pathological low oxygen conditions, such as preeclampsia. In high-altitude and in preeclamptic tissue, sFlt-1 localized within villi to perivascular regions, the syncytiotrophoblast layer, and syncytial knots. In first-trimester villous explants, low oxygen, but not hypoxia-reoxygenation (HR), increased sFlt-1 expression. Moreover, exposure of villous explants to dimethyloxalyl-glycin, a pharmacological inhibitor of prolyl-hydroxylases, which mimics hypoxia by increasing HIF-1alpha stability, increased sFlt-1 expression. Conversely, HIF-1alpha knockdown using antisense oligonucleotides, decreased sFlt-1 expression. In conclusion, placental sFlt-1 expression is increased by both physiologically and pathologically low levels of oxygen. This oxygen-induced effect is mediated via the transcription factor HIF-1. Low oxygen levels, as opposed to intermittent oxygen tension (HR) changes, play an important role in regulating sFlt-1 expression in the developing human placenta and hence may contribute to the development of preeclampsia.

A novel Mtd splice isoform is responsible for trophoblast cell death in pre-eclampsia

Pre-eclampsia is a serious disorder of human pregnancy, characterized by decreased utero-placental perfusion and increased trophoblast cell death. Presently, the mechanisms regulating trophoblast cell death in pre-eclampsia are not fully elucidated. Herein, we have identified a novel Mtd/Bok splice isoform (Mtd-P) resulting from exon-II skipping. Mtd-P expression was unique to early-onset severe pre-eclamptic placentae as assessed by quantitative real-time-PCR and immunoblotting. Mtd-P overexpression in cell lines (BeWo: cytotrophoblast-derived; and CHO: ovary-derived) resulted in increased apoptotic cell death as assessed by caspase-3 cleavage, internucleosomal DNA laddering and mitochondrial depolarization. Moreover, Mtd-P expression increased under conditions of low oxygenation/oxidative stress in human villous explants. Antisense knockdown of Mtd under conditions of oxidative stress resulted in decreased caspase-3 cleavage. We conclude that under conditions of reduced oxygenation/oxidative stress, Mtd-P causes trophoblast cell death in pre-eclampsia and hence may contribute to the molecular events leading to the clinical manifestations of this disease.

Molecular evidence of placental hypoxia in preeclampsia

BACKGROUND

Oxygen plays a central role in human placental pathologies including preeclampsia, a leading cause of fetal and maternal death and morbidity. Insufficient uteroplacental oxygenation in preeclampsia is believed to be responsible for the molecular events leading to the clinical manifestations of this disease.

DESIGN

Using high-throughput functional genomics, we determined the global gene expression profiles of placentae from high altitude pregnancies, a natural in vivo model of chronic hypoxia, as well as that of first-trimester explants under 3 and 20% oxygen, an in vitro organ culture model. We next compared the genomic profile from these two models with that obtained from pregnancies complicated by preeclampsia. Microarray data were analyzed using the binary tree-structured vector quantization algorithm, which generates global gene expression maps.

RESULTS

Our results highlight a striking global gene expression similarity between 3% O(2)-treated explants, high-altitude placentae, and importantly placentae from preeclamptic pregnancies. We demonstrate herein the utility of explant culture and high-altitude placenta as biologically relevant and powerful models for studying the oxygen-mediated events in preeclampsia.

CONCLUSION

Our results provide molecular evidence that aberrant global placental gene expression changes in preeclampsia may be due to reduced oxygenation and that these events can successfully be mimicked by in vivo and in vitro models of placental hypoxia.

Constraints on proper folding of the amino terminal domains of group III metabotropic glutamate receptors

The glutamate binding site of the G-protein coupled metabotropic glutamate receptors (mGluRs) is contained within the large extracellular amino terminal domain (ATD) of the receptor. In this study, we examined the ligand binding properties and cellular dispositions of the membrane-bound mGluR4 and mGluR8 subtypes of mGluRs, and a series of truncated versions of these receptors. Truncation of the ATDs of mGluR4 and mGluR8 40 amino acids upstream of the first transmembrane domain produced soluble proteins that were secreted into the cell culture media of transfected human embryonic kidney cells. The soluble receptors retained ligand binding capabilities. Additional constructs of the ATDs of mGluR4 and mGluR8 were assessed for their ability to bind the agonist [(3)H]L-AP4 and for secretion from cells. A shorter mGluR4 construct truncated 98 amino acids upstream from the first transmembrane domain failed to bind [(3)H]L-AP4, while the analogous mGluR8 construct displayed a low level of binding. Unlike the full-length receptors, which were expressed on the cell surface, or the soluble constructs which were secreted, the shorter constructs were primarily associated with intracellular membranes. These observations suggest that the cysteine-rich region may be important for efficient secretion, but not absolutely obligatory for ligand binding. Surprisingly, longer constructs encoding the entire ATDs of mGluR4 and mGluR8 failed to bind ligand and were localized intracellularly. Together, these findings demonstrate that there are strict limitations on the proper folding of truncated versions of the ATDs of mGluR4 and mGluR8. Specifically, all of the leucine-isoleucine-valine binding protein homology region, and part of the cysteine-rich region is required for optimal secretion in a soluble form that retains ligand binding activity.