Jan Bolinder

Effects of dapagliflozin on body weight, total fat mass, and regional adipose tissue distribution in patients with type 2 diabetes mellitus with inadequate glycemic control on metformin.

CONTEXT Dapagliflozin, a selective sodium-glucose cotransporter 2 (SGLT2) inhibitor, reduces hyperglycemia in patients with type 2 diabetes mellitus (T2DM) by increasing urinary glucose excretion, and weight loss is a consistent associated finding. OBJECTIVES Our objectives were to confirm weight loss with dapagliflozin and establish through body composition measurements whether weight loss is accounted for by changes in fat or fluid components. DESIGN AND SETTING This was a 24-wk, international, multicenter, randomized, parallel-group, double-blind, placebo-controlled study with ongoing 78-wk site- and patient-blinded extension period at 40 sites in five countries. PATIENTS Included were 182 patients with T2DM (mean values: women 63.3 and men 58.6 yr of age; hemoglobin A1c 7.17%, body mass index 31.9 kg/m2, and body weight 91.5 kg) inadequately controlled on metformin. INTERVENTION Dapagliflozin 10 mg/d or placebo was added to open-label metformin for 24 wk. MAIN OUTCOME MEASURES Primary endpoint was total body weight (TBW) change from baseline at wk 24. Key secondary endpoints were waist circumference and dual-energy x-ray absorptiometry total-body fat mass (FM) changes from baseline at wk 24, and patient proportion achieving body weight reduction of at least 5% at wk 24. In a subset of patients, magnetic resonance assessment of visceral adipose tissue (VAT) and sc adipose tissue (SAT) volume and hepatic lipid content were also evaluated. RESULTS At wk 24, placebo-corrected changes with dapagliflozin were as follows: TBW, -2.08 kg [95% confidence interval (CI)=-2.84 to -1.31; P<0.0001]; waist circumference, -1.52 cm (95% CI=-2.74 to -0.31; P=0.0143); FM, -1.48 kg (95% CI=-2.22 to -0.74; P=0.0001); proportion of patients achieving weight reduction of at least 5%, +26.2% (95% CI=15.5 to 36.7; P<0.0001); VAT, -258.4 cm3 (95% CI=-448.1 to -68.6; nominal P=0.0084); SAT, -184.9 cm3 (95% CI=-359.7 to -10.1; nominal P=0.0385). In the dapagliflozin vs. placebo groups, respectively, serious adverse events were reported in 6.6 vs. 1.1%; events suggestive of vulvovaginitis, balanitis, and related genital infection in 3.3 vs. 0%; and lower urinary tract infections in 6.6 vs. 2.2%. CONCLUSIONS Dapagliflozin reduces TBW, predominantly by reducing FM, VAT and SAT in T2DM inadequately controlled with metformin.

Adrenergic regulation of lipolysis in situ at rest and during exercise.

The adrenergic regulation of lipolysis was investigated in situ at rest and during standardized bicycle exercise in nonobese healthy subjects, using microdialysis of the extracellular space in subcutaneous adipose tissue. The glycerol concentration was about two times greater in adipose tissue than in venous blood. At rest, the glycerol concentration in adipose tissue was rapidly increased by 100% (P less than 0.01) after the addition of phentolamine to the ingoing perfusate, whereas addition of propranolol did not alter the adipose tissue glycerol level. Glycerol in adipose tissue and plasma increased during exercise and decreased in the postexercise period. Propranolol in the perfusate almost completely inhibited the increase in the tissue dialysate glycerol during the exercise-postexercise period. Phentolamine, however, was completely ineffective in this respect. During exercise, the lipolytic activity was significantly more marked in abdominal than in gluteal adipose tissue; this was much more apparent in women than in men. Thus, in vivo lipolysis in subcutaneous adipose tissue is regulated by different adrenergic mechanisms at rest and during exercise. Alpha-adrenergic inhibitory effects modulate lipolysis at rest, whereas beta-adrenergic stimulatory effects modulate lipolysis during exercise. In addition, regional differences in lipolysis are present in vivo during exercise, which seem governed by factors relating to sex.

Effect of continuous glucose monitoring on hypoglycemia in type 1 diabetes

OBJECTIVE To assess the impact of continuous glucose monitoring on hypoglycemia in people with type 1 diabetes. RESEARCH DESIGN AND METHODS In this randomized, controlled, multicenter study, 120 children and adults on intensive therapy for type 1 diabetes and a screening level of glycated hemoglobin A1c (HbA1c) <7.5% were randomly assigned to a control group performing conventional home monitoring with a blood glucose meter and wearing a masked continuous glucose monitor every second week for five days or to a group with real-time continuous glucose monitoring. The primary outcome was the time spent in hypoglycemia (interstitial glucose concentration <63 mg/dL) over a period of 26 weeks. Analysis was by intention to treat for all randomized patients. RESULTS The time per day spent in hypoglycemia was significantly shorter in the continuous monitoring group than in the control group (mean ± SD 0.48 ± 0.57 and 0.97 ± 1.55 h/day, respectively; ratio of means 0.49; 95% CI 0.26–0.76; P = 0.03). HbA1c at 26 weeks was lower in the continuous monitoring group than in the control group (difference −0.27%; 95% CI −0.47 to −0.07; P = 0.008). Time spent in 70 to 180 mg/dL normoglycemia was significantly longer in the continuous glucose monitoring group compared with the control group (mean hours per day, 17.6 vs. 16.0, P = 0.009). CONCLUSIONS Continuous glucose monitoring was associated with reduced time spent in hypoglycemia and a concomitant decrease in HbA1c in children and adults with type 1 diabetes.

Differences at the Receptor and Postreceptor Levels Between Human Omental and Subcutaneous Adipose Tissue in the Action of Insulin on Lipolysis

The possible existence of regional differences in the antilipolytic action of insulin in human adipose tissue was investigated in vitro. Insulin-induced inhibition of glycerol release and insulin binding, measured in terms of receptor number, receptor affinity, and dissociation rates, were determined in omental and subcutaneous adipose tissue segments and isolated fat cells of 16 nonobese subjects who were undergoing elective abdominal surgery but were otherwise healthy. The sensitivity of the antilipolytic effect of insulin was higher in subcutaneous than in omental adipose tissue; the half-maximal effect was obtained with 1 and 3 μU/ml of insulin, respectively (P < 0.01). Responsiveness of the antilipolytic effect of insulin was threefold higher in the subcutaneous than in the omental region (P < 0.005). Insulin receptor affinity was significantly higher in subcutaneous than in omental fat cells, but there was no difference in receptor number (about 300,000 sites/cell). 125I-insulin dissociated more rapidly from omental than from subcutaneous adipocytes in both the absence and the presence of excess native insulin. The data suggest that significant regional differences exist in the antilipolytic action of insulin in man; omental fat being less responsive than subcutaneous fat. The difference involves the insulin receptor affinity, which is caused at least partly by variations in the insulin dissociation rate but is also due to differences in insulin action at the postreceptor level.

AAPS-FDA workshop white paper: Microdialysis principles, application, and regulatory perspectives

Many decisions in drug development and medical practice are based on measuring blood concentrations of endogenous and exogenous molecules. Yet most biochemical and pharmacological events take place in the tissues. Also, most drugs with few notable exceptions exert their effects not within the bloodstream, but in defined target tissues into which drugs have to distribute from the central compartment. Assessing tissue drug chemistry has, thus, for long been viewed as a more rational way to provide clinically meaningful data rather than gaining information from blood samples. More specifically, it is often the extracellular (interstitial) tissue space that is most closely related to the site of action (biophase) of the drug. Currently microdialysis (μD) is the only tool available that explicitly provides data on the extracellular space. Although μD as a preclinical and clinical tool has been available for two decades, there is still uncertainty about the use of μD in drug research and development, both from a methodological and a regulatory point of view. In an attempt to reduce this uncertainty and to provide an overview of the principles and applications of μD in preclinical and clinical settings, an AAPS-FDA workshop took place in November 2005 in Nashville, TN, USA. Stakeholders from academia, industry and regulatory agencies presented their views on μD as a tool in drug research and development.

Dapagliflozin maintains glycaemic control while reducing weight and body fat mass over 2 years in patients with type 2 diabetes mellitus inadequately controlled on metformin

Dapagliflozin, a highly selective inhibitor of sodium‐glucose cotransporter 2 (SGLT2), reduces hyperglycaemia and weight in patients with type 2 diabetes mellitus (T2DM) by increasing urinary glucose excretion. Long‐term glycaemic control, body composition and bone safety were evaluated in patients with T2DM after 102 weeks of dapagliflozin treatment.

Regional difference in insulin inhibition of non-esterified fatty acid release from human adipocytes: relation to insulin receptor phosphorylation and intracellular signalling through the insulin receptor substrate-1 pathway

Summary Increased mobilization of non-esterified fatty acids (NEFA) from visceral as opposed to peripheral fat depots can lead to metabolic disturbances because of the direct portal link between visceral fat and the liver. Compared with peripheral fat, visceral fat shows a decreased response to insulin. The mechanisms behind these site variations were investigated by comparing insulin action on NEFA metabolism with insulin receptor signal transduction through the insulin receptor substrate-1 (IRS-1) pathway in omental (visceral) and subcutaneous human fat obtained during elective surgery. Insulin inhibited lipolysis and stimulated NEFA re-esterification. This was counteracted by wortmannin, an inhibitor of phosphaditylinositol (PI) 3-kinase. The effects of insulin on antilipolysis and NEFA re-esterification were greatly reduced in omental fat cells. Insulin receptor binding capacity, mRNA and protein expression did not differ between the cell types. Insulin was four times more effective in stimulating tyrosine phosporylation of the insulin receptor in subcutaneous fat cells (p < 0.001). Similarly, insulin was two to three times more effective in stimulating tyrosine phosphorylation of IRS-1 in subcutaneous fat cells (p < 0.01). This finding could be explained by finding that IRS-1 protein expression was reduced by 50 ± 8 % in omental fat cells (p < 0.01). In omental fat cells, maximum insulin-stimulated association of the p85 kDa subunit of PI 3-kinase to phosphotyrosine proteins and phosphotyrosine associated PI 3-kinase activity were both reduced by 50 % (p < 0.05 or better). Thus, the ability of insulin to induce antilipolysis and stimulate NEFA re-esterification is reduced in visceral adipocytes. This reduction can be explained by reduced insulin receptor autophosphorylation and signal transduction through an IRS-1 associated PI 3-kinase pathway in visceral adipocytes. [Diabetologia (1998) 41: 1343–1354]

Microdialysis of subcutaneous adipose tissue in vivo for continuous glucose monitoring in man

Subcutaneous adipose tissue extracellular glucose was investigated in vivo in man with a microdialysis technique. A small dialysis probe (4 or 10 x 0.5 mm) was implanted subcutaneously, and was perfused continuously with a micro-infusion pump. Dialysate samples were collected in 15-min periods. A transient yield of ATP was recorded immediately after insertion of the probe; thereafter ATP was almost undetectable. During steady-state conditions the tissue dialysate glucose concentration remained constant for at least 2 h, which indicated that there was no drainage of glucose from the interstitial fluid to the tissue dialysate. Simultaneous dialysis of venous blood and subcutaneous fat in rats showed that the recovery of glucose from the adipose tissue interstitial fluid to the dialysate was only 20% of that from blood. However, in vivo dialysis of human adipose tissue with glucose-containing solutions produced an equilibrium with the extracellular space at a glucose concentration that was similar to the blood glucose concentration. After oral glucose ingestion and following i.v. insulin and glucose administration the relative variations in subcutaneous glucose closely resembled those in blood glucose. It is concluded that the subcutaneous implantation of the presently used small dialysis device causes only minor and transient traumatic effects. The dialysis recovery of glucose is lower in adipose tissue than in blood. However, the relative kinetics of subcutaneous tissue dialysate glucose are closely related to variations in the blood glucose concentration, and thus may be used for monitoring of glycaemic control in man.

Microdialysis of adipose tissue

Abstract. Although microdialysis has been available for almost two decades, it has only recently been applied in investigations of adipose tissue. The microdialysis technique enables continuous sampling of metabolites and other small molecules from the extracellular space of subcutaneous adipose tissue from intact animals or man, and the exposure of this compartment locally to metabolically active agents without causing generalized effects. To date, the method has been used to measure the steady‐state interstitial levels of metabolites and to investigate the regulation of lipolysis and carbohydrate metabolism in situ in subcutaneous adipose tissue. Apart from a great potential for experimental research, the microdialysis method offers several new possibilities for clinical investigation. Because microdialysis probes are easy to implant and cause little discomfort, they may be used for continuous monitoring of glucose and glycerol (lipolysis index) in the treatment of diabetes, obesity and other disorders characterized by disturbances in lipid and carbohydrate metabolism.

Novel glucose-sensing technology and hypoglycaemia in type 1 diabetes: a multicentre, non-masked, randomised controlled trial

BACKGROUND Tight control of blood glucose in type 1 diabetes delays onset of macrovascular and microvascular diabetic complications; however, glucose levels need to be closely monitored to prevent hypoglycaemia. We aimed to assess whether a factory-calibrated, sensor-based, flash glucose-monitoring system compared with self-monitored glucose testing reduced exposure to hypoglycaemia in patients with type 1 diabetes. METHOD In this multicentre, prospective, non-masked, randomised controlled trial, we enrolled adult patients with well controlled type 1 diabetes (HbA1c ≤58 mmol/mol [7·5%]) from 23 European diabetes centres. After 2 weeks of all participants wearing the blinded sensor, those with readings for at least 50% of the period were randomly assigned (1:1) to flash sensor-based glucose monitoring (intervention group) or to self-monitoring of blood glucose with capillary strips (control group). Randomisation was done centrally using the biased-coin minimisation method dependent on study centre and type of insulin administration. Participants, investigators, and study staff were not masked to group allocation. The primary outcome was change in time in hypoglycaemia (<3·9 mmol/L [70 mg/dL]) between baseline and 6 months in the full analysis set (all participants randomised; excluding those who had a positive pregnancy test during the study). This trial was registered with ClinicalTrials.gov, number NCT02232698. FINDINGS Between Sept 4, 2014, and Feb 12, 2015, we enrolled 328 participants. After the screening and baseline phase, 120 participants were randomly assigned to the intervention group and 121 to the control group, with outcomes being evaluated in 119 and 120, respectively. Mean time in hypoglycaemia changed from 3·38 h/day at baseline to 2·03 h/day at 6 months (baseline adjusted mean change -1·39) in the intervention group, and from 3·44 h/day to 3·27 h/day in the control group (-0·14); with the between-group difference of -1·24 (SE 0·239; p<0·0001), equating to a 38% reduction in time in hypoglycaemia in the intervention group. No device-related hypoglycaemia or safety issues were reported. 13 adverse events were reported by ten participants related to the sensor-four of allergy events (one severe, three moderate); one itching (mild); one rash (mild); four insertion-site symptom (severe); two erythema (one severe, one mild); and one oedema (moderate). There were ten serious adverse events (five in each group) reported by nine participants; none were related to the device. INTERPRETATION Novel flash glucose testing reduced the time adults with well controlled type 1 diabetes spent in hypoglycaemia. Future studies are needed to assess the effectiveness of this technology in patients with less well controlled diabetes and in younger age groups. FUNDING Abbott Diabetes Care.