Pharmacokinetic and pharmacodynamic properties of once-weekly insulin icodec in individuals with type 2 diabetes.

AIMS: To characterize the pharmacokinetic and pharmacodynamic properties of once-weekly insulin icodec in type 2 diabetes (T2D). MATERIALS AND METHODS: In an open-label trial, 46 individuals with T2D (18-75 years; body mass index 18.0-38.0 kg/m2 ; glycated haemoglobin ≤75 mmol/mol [≤9%]; basal insulin-treated) received subcutaneous once-weekly icodec for ≥8 weeks at individualized doses, aiming at a pre-breakfast plasma glucose concentration of 4.4 to 7.0 mmol/L (80-126 mg/dL) on the last three mornings of each weekly dosing interval. Frequent blood sampling to assess total serum icodec concentration (ie, albumin-bound and unbound) occurred from first icodec dose until 35 days after last dose. Icodec trough concentrations following initiation of once-weekly dosing were predicted by pharmacokinetic modelling. During the final 3 weeks of icodec treatment, while at steady state, the icodec glucose-lowering effect was assessed in three glucose clamps (target 7.5 mmol/L [135 mg/dL]): 0 to 36, 40 to 64 and 144 to 168 h post-dose, thus covering the initial, middle and last part of the 1-week dosing interval. Glucose-lowering effect during a complete dosing interval was predicted by pharmacokinetic-pharmacodynamic modelling. RESULTS: Model-predicted icodec steady state was attained after 3 to 4 weeks. At steady state, model-predicted daily proportions of glucose-lowering effect on days 1 to 7 of the 1-week dosing interval were 14.1%, 16.1%, 15.8%, 15.0%, 14.0%, 13.0% and 12.0%, respectively. Icodec duration of action was at least 1 week in all participants. Once-weekly icodec was overall safe and well tolerated in the current trial. CONCLUSIONS: The pharmacokinetic and pharmacodynamic characteristics of icodec in individuals with T2D support its potential as a once-weekly basal insulin.

Hypoglycaemia frequency and physiological response after double or triple doses of once-weekly insulin icodec vs once-daily insulin glargine U100 in type 2 diabetes: a randomised crossover trial.

AIMS/HYPOTHESIS: This study compared the frequency of hypoglycaemia, time to hypoglycaemia and recovery from hypoglycaemia after double or triple doses of once-weekly insulin icodec vs once-daily insulin glargine U100. Furthermore, the symptomatic and counterregulatory responses to hypoglycaemia were compared between icodec and glargine U100 treatment. METHODS: In a randomised, single-centre (Department of Internal Medicine, Division of Endocrinology and Diabetology, Medical University of Graz, Graz, Austria), open-label, two-period crossover trial, individuals with type 2 diabetes (age 18-72 years, BMI 18.5-37.9 kg/m2, HbA1c ≤75 mmol/mol [≤9.0%]) treated with basal insulin with or without oral glucose-lowering drugs received once-weekly icodec (for 6 weeks) and once-daily glargine U100 (for 11 days). Total weekly doses were equimolar based on individual titration of daily glargine U100 during the run-in period (target fasting plasma glucose [PG]: 4.4-7.2 mmol/l). Randomisation was carried out by assigning a randomisation number to each participant in ascending order, which encoded to one of two treatment sequences via a randomisation list prepared prior to the start of the trial. At steady state, double and triple doses of icodec and glargine U100 were administered followed by hypoglycaemia induction: first, euglycaemia was maintained at 5.5 mmol/l by variable i.v. infusion of glucose; glucose infusion was then terminated, allowing PG to decrease to no less than 2.5 mmol/l (target PGnadir). The PGnadir was maintained for 15 min. Euglycaemia was restored by constant i.v. glucose (5.5 mg kg-1 min-1). Hypoglycaemic symptoms score (HSS), counterregulatory hormones, vital signs and cognitive function were assessed at predefined PG levels towards the PGnadir. RESULTS: Hypoglycaemia induction was initiated in 43 and 42 participants after double dose of icodec and glargine U100, respectively, and in 38 and 40 participants after triple doses, respectively. Clinically significant hypoglycaemia, defined as PGnadir <3.0 mmol/l, occurred in comparable proportions of individuals treated with icodec vs glargine U100 after double (17 [39.5%] vs 15 [35.7%]; p=0.63) and triple (20 [52.6%] vs 28 [70.0%]; p=0.14) doses. No statistically significant treatment differences were observed in the time to decline from PG values of 5.5 mmol/l to 3.0 mmol/l (2.9-4.5 h after double dose and 2.2-2.4 h after triple dose of the insulin products). The proportion of participants with PGnadir ≤2.5 mmol/l was comparable between treatments after double dose (2 [4.7%] for icodec vs 3 [7.1%] for glargine U100; p=0.63) but higher for glargine U100 after triple dose (1 [2.6%] vs 10 [25.0%]; p=0.03). Recovery from hypoglycaemia by constant i.v. glucose infusion took <30 min for all treatments. Analyses of the physiological response to hypoglycaemia only included data from participants with PGnadir <3.0 mmol/l and/or the presence of hypoglycaemic symptoms; in total 20 (46.5%) and 19 (45.2%) individuals were included after a double dose of icodec and glargine U100, respectively, and 20 (52.6%) and 29 (72.5%) individuals were included after a triple dose of icodec and glargine U100, respectively. All counterregulatory hormones (glucagon, adrenaline [epinephrine], noradrenaline [norepinephrine], cortisol and growth hormone) increased during hypoglycaemia induction with both insulin products at both doses. Following triple doses, the hormone response was greater with icodec vs glargine U100 for adrenaline at PG3.0 mmol/l (treatment ratio 2.54 [95% CI 1.69, 3.82]; p<0.001), and cortisol at PG3.0 mmol/l (treatment ratio 1.64 [95% CI 1.13, 2.38]; p=0.01) and PGnadir (treatment ratio 1.80 [95% CI 1.09, 2.97]; p=0.02). There were no statistically significant treatment differences in the HSS, vital signs and cognitive function. CONCLUSIONS/INTERPRETATION: Double or triple doses of once-weekly icodec lead to a similar risk of hypoglycaemia compared with double or triple doses of once-daily glargine U100. During hypoglycaemia, comparable symptomatic and moderately greater endocrine responses are elicited by icodec vs glargine U100. TRIAL REGISTRATION: ClinicalTrials.gov NCT03945656. FUNDING: This study was funded by Novo Nordisk A/S.

Pharmacokinetics and Pharmacodynamics of a Novel U500 Insulin Aspart Formulation: A Randomized, Double-Blind, Crossover Study in People With Type 1 Diabetes.

OBJECTIVE: To evaluate the pharmacokinetics, pharmacodynamics, and safety of a novel U500 insulin aspart formulation (AT278 U500) compared with insulin aspart (IAsp U100). RESEARCH DESIGN AND METHODS: This single-center, randomized, double-blind study was conducted in 38 men with type 1 diabetes (body weight ≤100 kg and total insulin dose <1.2 units/kg/day). Participants received a single dose of either AT278 U500 or IAsp U100 (0.3 units/kg s.c.) in a crossover design, followed by an 8-h euglycemic clamp in the absence of basal insulin. RESULTS: With AT278 U500, onset of appearance in serum was 6 min earlier (P < 0.0001) and reached 50% of maximum concentration 23 min faster (P < 0.0001). Insulin exposure with AT278 U500 was 4.0-fold higher within the first 30 min (95% CI 3.29, 4.90), 1.5-fold higher within the first 60 min (95% CI 1.35, 1.76), and statistically superior up to 90 min postdose (P < 0.05). With AT278 U500, onset of action was 10 min earlier (P < 0.0001) and reached 50% of maximum glucose infusion rate 20 min faster (P < 0.0001). The glucose-lowering effect with AT278 U500 was 8.9-fold higher within the first 30 min (95% CI 5.96, 17.46), 2.4-fold higher within the first 60 min (95% CI 1.92, 3.22), and statistically superior up to 2 h postdose (P < 0.0001). Overall insulin exposure and glucose-lowering effect were comparable. No significant safety findings were observed. CONCLUSIONS: AT278 U500 offers rapid-acting characteristics in a reduced dose volume, with accelerated absorption and onset of action compared with IAsp U100 in the studied population.

Assessment of Two Different Glucagon Assays in Healthy Individuals and Type 1 and Type 2 Diabetes Patients.

Methods for glucagon analysis suffered in the past from lack of specificity and a narrow sensitivity range, which has led to inaccurate results and to the suggestion that type 1 diabetes (T1D) and type 2 diabetes (T2D) patients have elevated fasting glucagon levels. However, the availability of more specific and more sensitive methods to detect intact glucagon has shown that actual glucagon levels are lower than previously assumed. This study aimed to characterize fasting plasma glucagon levels in healthy individuals and T1D and T2D patients with two different glucagon assays. The study included 20 healthy individuals, 20 T1D and 20 T2D patients. Blood was collected under fasting conditions. A double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) and a conventional radioimmunoassay (RIA) were used. A significant difference in fasting glucagon levels between healthy individuals and T2D was observed by ELISA, but not by RIA. ELISA also yielded lower glucagon levels in healthy individuals than in T1D and T2D patients which RIA did not. RIA produced significantly (p = 0.0001) higher overall median glucagon values than ELISA in a pooled analysis. These results underline the notion that the choice of selective laboratory methods is highly relevant for mechanistic endocrine research.

Blood glucose response after oral lactulose intake in type 2 diabetic individuals.

BACKGROUND: Lactulose is approved for the symptomatic treatment of constipation, a gastrointestinal (GI) complication common in individuals with diabetes. Lactulose products contain carbohydrate impurities (e.g., lactose, fructose, galactose), which occur during the lactulose manufacturing process. These impurities may affect the blood glucose levels of individuals with type 2 diabetes mellitus (T2DM) using lactulose for the treatment of mild constipation. A previous study in healthy subjects revealed no increase in blood glucose levels after oral lactulose intake. However, it is still unclear whether the intake of lactulose increases blood glucose levels in individuals with diabetes. AIM: To evaluate the blood glucose profile after oral lactulose intake in mildly constipated, non-insulin-dependent subjects with T2DM in an outpatient setting. METHODS: This prospective, double-blind, randomized, controlled, single-center trial was conducted at the Clinical Research Center at the Medical University of Graz, Austria, in 24 adult Caucasian mildly constipated, non-insulin-dependent subjects with T2DM. Eligible subjects were randomized and assigned to one of six treatment sequences, each consisting of four treatments stratified by sex using an incomplete block design. Subjects received a single dose of 20 g or 30 g lactulose (crystal and liquid formulation), water as negative control or 30 g glucose as positive control. Capillary blood glucose concentrations were measured over a period of 180 min post dose. The primary endpoint was the baseline-corrected area under the curve of blood glucose concentrations over the complete assessment period [AUCbaseline_c (0-180 min)]. Quantitative comparisons were performed for both lactulose doses and formulations vs water for the equal lactulose dose vs glucose, as well as for liquid lactulose vs crystal lactulose. Safety parameters included GI tolerability, which was assessed at 180 min and 24 h post dose, and adverse events occurring up to 24 h post dose. RESULTS: In 24 randomized and analyzed subjects blood glucose concentration-time curves after intake of 20 g and 30 g lactulose were almost identical to those after water intake for both lactulose formulations despite the different amounts of carbohydrate impurities (≤ 3.0% for crystals and approx. 30% for liquid). The primary endpoint [AUCbaseline_c (0-180 min)] was not significantly different between lactulose and water regardless of lactulose dose and formulation. Also with regard to all secondary endpoints lactulose formulations showed comparable results to water with one exception concerning maximum glucose level. A minor increase in maximum blood glucose was observed after the 30 g dose, liquid lactulose, in comparison to water with a mean treatment difference of 0.63 mmol/L (95% confidence intervals: 0.19, 1.07). Intake of 30 g glucose significantly increased all blood glucose endpoints vs 30 g liquid and crystal lactulose, respectively (all P < 0.0001). No differences in blood glucose response were observed between the different lactulose formulations. As expected, lactulose increased the number of bowel movements and was generally well tolerated. Subjects experienced only mild to moderate GI symptoms due to the laxative action of lactulose. CONCLUSION: Blood glucose AUCbaseline_c (0-180 min) levels in mildly constipated, non-insulin dependent subjects with T2DM are not affected by the carbohydrate impurities contained in 20 g and 30 g crystal or liquid lactulose formulations.

EndoBarrier™ Implantation Rapidly Improves Insulin Sensitivity in Obese Individuals with Type 2 Diabetes Mellitus.

The EndoBarrier™ medical device is a duodenal-jejunal bypass liner designed to mimic the effects of gastric bypass surgery to induce weight loss and glycaemic improvement. In this study, 10 participants with type 2 diabetes mellitus (T2DM), a mean body mass index (BMI) of 43.3 ± 5.0 (kg/m2) and a mean glycated haemoglobin A1c (HbA1c) of 60.6 ± 8.6 mmol/mol were examined at baseline (before implantation of EndoBarrier™), 4 weeks after implantation, at 36 weeks (right before explantation) and 24 weeks after the removal of the device to explore the short and long-term effects on glucose metabolism. Besides a significant reduction in body weight and fat mass, EndoBarrier™ treatment significantly improved insulin sensitivity during Botnia clamp investigations after four weeks of implantation. The beneficial effects decreased over time but remained significant 24 weeks after removal of the device.

Pharmacokinetics and Pharmacodynamics of Three Different Formulations of Insulin Aspart: A Randomized, Double-Blind, Crossover Study in Men With Type 1 Diabetes.

OBJECTIVE: To investigate the pharmacokinetic and pharmacodynamic properties and safety of a novel formulation of insulin aspart (AT247) versus two currently marketed insulin aspart formulations (NovoRapid [IAsp] and Fiasp [faster IAsp]). RESEARCH DESIGN AND METHODS: This single-center, randomized, double-blind, three-period, crossover study was conducted in 19 men with type 1 diabetes, receiving single dosing of trial products (0.3 units/kg) in a random order on three visits. Pharmacokinetics and pharmacodynamics were assessed during a euglycemic clamp lasting up to 8 h. RESULTS: Onset of insulin appearance was earlier for AT247 compared with IAsp (-12 min [95% CI -14; -8], P = 0.0004) and faster IAsp (-2 min [-5; -2], P = 0.0003). Onset of action was accelerated compared with IAsp (-23 min [-37; -15], P = 0.0004) and faster IAsp (-9 min [-11; -3], P = 0.0006). Within the first 60 min, a higher exposure was observed for AT247 compared with IAsp by the area under the curve (AUC) glucose infusion rate (GIR) from 0 to 60 min (AUCAsp0-60min: treatment ratio vs. IAsp 2.3 [1.9; 2.9] vs. faster IAsp 1.5 [1.3; 1.8]), which was underpinned by a greater early glucose-lowering effect (AUCGIR,0-60min: treatment ratio vs. IAsp 2.8 [2.0; 5.5] vs. faster IAsp 1.7 [1.3; 2.3]). Furthermore, an earlier offset of exposure was observed for AT247 compared with IAsp (-32 min [-58; -15], P = 0.0015) and faster IAsp (-27 min [-85; -15], P = 0.0017), while duration of the glucose-lowering effect, measured by time to late half-maximum effect, did not differ significantly. CONCLUSIONS: AT247 exhibited an earlier insulin appearance, exposure, and offset, with corresponding enhanced early glucose-lowering effect compared with IAsp and faster IAsp. It therefore represents a promising candidate in the pursuit for second-generation prandial insulin analogs to improve postprandial glycemic control.

Hypoglycaemia leads to a delayed increase in platelet and coagulation activation markers in people with type 2 diabetes treated with metformin only: Results from a stepwise hypoglycaemic clamp study.

AIMS: To investigate the effect of hypoglycaemia on platelet and coagulation activation in people with type 2 diabetes. MATERIALS AND METHODS: This monocentric, open, single-arm, mechanistic trial included 14 people with established type 2 diabetes (four women, 10 men, age 55 ± 7 years, glycated haemoglobin concentration 51 ± 7 mmol/mol) receiving metformin monotherapy. A stepwise hyperinsulinaemic-hypoglycaemic clamp experiment (3.5 and 2.5 mmol/L, for 30 minutes respectively) was performed, aiming to investigate platelet and coagulation activity during predefined plateaus of hypoglycaemia, as well as 1 day and 7 days later. RESULTS: While platelet activation assessed by light transmittance aggregometry did not significantly increase after the hypoglycaemic clamp procedure, the more sensitive flow cytometry-based measurement of platelet surface activation markers showed hypoglycaemia-induced activation 24 hours (PAC1pos CD62Ppos , PAC1pos CD63Ppos and PAC1pos CD62Ppos CD63pos ; P < .01) and 7 days after the hypoglycaemic clamp (P < .001 for PAC1pos CD63pos ; P < .01 for PAC1pos CD62Ppos and PAC1pos CD62Ppos CD63pos ) in comparison to baseline. Coagulation markers, such as fibrinogen, D-dimer, plasminogen activator inhibitor-1, von Willebrand factor activity and factor VIII, were also significantly increased, an effect that was most pronounced 24 hours after the hypoglycaemic clamp. CONCLUSION: A single event of insulin-induced hypoglycaemia led to an increase in markers of platelet activation and coagulation in people with early stages of type 2 diabetes on metformin therapy. However, the activation occurred with a delay and was evident 24 hours and 7 days after the actual hypoglycaemic episode.

Fast-acting insulin aspart in people with type 2 diabetes: Earlier onset and greater initial exposure and glucose-lowering effect compared with insulin aspart.

AIMS: To investigate the pharmacokinetic/pharmacodynamic properties of fast-acting insulin aspart (faster aspart) versus insulin aspart (IAsp) in people with type 2 diabetes (T2D). MATERIALS AND METHODS: In a randomized, double-blind, crossover design, 61 people with T2D usually treated with insulin ± oral antidiabetic drug(s) received single-dose faster aspart and IAsp (0.3 U/kg) on separate visits. Blood samples for pharmacokinetic assessment were collected frequently until 12 hours post-dose. Glucose-lowering effect was determined in a euglycaemic clamp lasting up to 12 hours post-dose (target 5.0 mmol/L). RESULTS: The serum IAsp pharmacokinetic profile and glucose-lowering effect profile were shifted to the left for faster aspart versus IAsp. Least squares mean (± SE) onset of appearance was 3.3 ± 0.3 minutes for faster aspart, which was 1.2 minutes earlier than for IAsp (95% confidence interval [CI] -1.8;-0.5; P = .001). Onset of action for faster aspart was 8.9 minutes earlier (95% CI -12.1;-5.7; P < .001) than for IAsp. During the first 30 minutes after dosing, 89% larger IAsp exposure (ratio faster aspart/IAsp 1.89 [95% CI 1.56;2.28]; P < .001) and 147% greater glucose-lowering effect (2.47 [95% CI 1.58;6.22]; P < .001) were observed for faster aspart compared with IAsp. Offset of exposure (time to 50% of maximum IAsp concentration in the late part of the pharmacokinetic profile) occurred earlier for faster aspart (difference faster aspart - IAsp -36.4 minutes [95% CI -55.3;-17.6]; P < .001). The treatment difference of faster aspart - IAsp in offset of glucose-lowering effect (time to 50% of maximum glucose infusion rate in the late part of the glucose infusion rate profile) was -14.4 minutes (95% CI -34.4;5.5; P = .152). CONCLUSIONS: In people with T2D, faster aspart was associated with earlier onset and greater initial exposure and glucose-lowering effect compared with IAsp, as previously shown in people with type 1 diabetes.

Impact of Duodeno-Jejunal Bypass Liner (EndoBarrierTM) Implantation on Insulin Sensitivity in Patients with Type 2 Diabetes Mellitus (T2DM): A Study Protocol for a Pilot Trial.

INTRODUCTION: A 60-cm endoscopically implantable duodenal-jejunal bypass liner (Endobarrier™, GI Dynamics, Lexington, MA, USA) has been introduced as a therapeutic option to support weight loss for a selected group of obese subjects with type 2 diabetes mellitus (T2DM). The sleeve prevents contact between chyme and the intestinal mucosa of the upper gastrointestinal tract. The primary aim of this study is to elucidate the changes in insulin sensitivity and beta-cell function after EndoBarrier™ implantation in obese patients with T2DM; changes in gut permeability and gut microbiome are also to be examined. METHODS: This is an open, single-center, prospective trial in which ten obese subjects with T2DM and suboptimal glycemic control (glycosylated hemoglobin A1c (HbA1c) level > 48 mmol/mol) are investigated with regards to EndoBarrier™ implantation. The Endobarrier™ is implanted shortly after baseline and left in situ for a period of 36 weeks. Dual-energy X-ray absorptiometry measurement, assessment of beta-cell function and insulin sensitivity as measured by a Botnia clamp procedure, and a mixed-meal tolerance test are performed prior to implantation and at 4, 36, and 64 weeks after implantation. The composition of the gut microbiota is characterized from stool using 454 pyrosequencing of 16S rRNA genes. Gut permeability is assessed by a differential sugar absorption method. PLANNED OUTCOME: This study will give mechanistic insights in particulr into changes of insulin sensitivity, beta-cell function or microbiome changes over time in subjects implanted with an EndobarrierTM device. TRIAL REGISTRATION: NCT02769728, Registered 12 May 2016. Current Protocol Date/Version: 04 September 2017/Version 1.9.

An Untargeted Metabolomics Approach to Characterize Short-Term and Long-Term Metabolic Changes after Bariatric Surgery.

Bariatric surgery is currently one of the most effective treatments for obesity and leads to significant weight reduction, improved cardiovascular risk factors and overall survival in treated patients. To date, most studies focused on short-term effects of bariatric surgery on the metabolic profile and found high variation in the individual responses to surgery. The aim of this study was to identify relevant metabolic changes not only shortly after bariatric surgery (Roux-en-Y gastric bypass) but also up to one year after the intervention by using untargeted metabolomics. 132 serum samples taken from 44 patients before surgery, after hospital discharge (1-3 weeks after surgery) and at a 1-year follow-up during a prospective study (NCT01271062) performed at two study centers (Austria and Switzerland). The samples included 24 patients with type 2 diabetes at baseline, thereof 9 with diabetes remission after one year. The samples were analyzed by using liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS, HILIC-QExactive). Raw data was processed with XCMS and drift-corrected through quantile regression based on quality controls. 177 relevant metabolic features were selected through Random Forests and univariate testing and 36 metabolites were identified. Identified metabolites included trimethylamine-N-oxide, alanine, phenylalanine and indoxyl-sulfate which are known markers for cardiovascular risk. In addition we found a significant decrease in alanine after one year in the group of patients with diabetes remission relative to non-remission. Our analysis highlights the importance of assessing multiple points in time in subjects undergoing bariatric surgery to enable the identification of biomarkers for treatment response, cardiovascular benefit and diabetes remission. Key-findings include different trend pattern over time for various metabolites and demonstrated that short term changes should not necessarily be used to identify important long term effects of bariatric surgery.

Intramyocellular lipid content in subjects with impaired fasting glucose after telmisartan treatment, a randomised cross-over trial.

Ectopic lipid accumulation in skeletal muscle is associated with insulin resistance. Telmisartan improves metabolic parameters in type 2 diabetic patients. The aim of our study was to evaluate the in vivo effect of telmisartan on intramyocellular lipid content (IMCL) in subjects with impaired fasting glucose (IFG) by magnetic resonance spectroscopy (MRS). We enrolled 10 subjects with IFG in a cross-over, placebo-controlled, randomized, double-blind trial, treated with 3 weeks of telmisartan (160 mg daily) or placebo. After completing each treatment, a hyperinsulinaemic euglycaemic clamp (1 mU/kg per min; 5 mmol/l; 120 min) to assess insulin action (metabolic clearance rate of glucose, MCR) and (1)H MRS of the m. tibialis anterior using a MR Scanner Siemens Vision operating at 1.5 T to evaluate IMCL content, were performed. Plasma adipokine levels were determined simultaneously. Telmisartan treatment resulted in a lower fasting plasma glucose (FPG) (p < 0.05), but insulin action was comparable to after placebo. Telmisartan did not affect IMCL content. After placebo, IMCL correlated negatively with total cholesterol (p < 0.001), MCR (p < 0.05) and adiponectin (p < 0.05) and positively with FPG (p < 0.05). After telmisartan treatment there was only a positive correlation between IMCL and TNFα (p < 0.05). IMCL content is related to parameters of glucose metabolism and insulin action in sedentary IFG subjects. A short telmisartan treatment did not affect the IMCL content despite its positive effect on FPG. The improvement in FPG was probably mediated through interference with other metabolic pathways.

Lipid-heparin infusion suppresses the IL-10 response to trauma in subcutaneous adipose tissue in humans.

An imbalance between pro- and anti-inflammatory cytokine productions in adipose tissue is thought to contribute to chronic, systemic, low-grade inflammation and consequently to an increased risk of cardiovascular complications in obese and type 2 diabetic patients. Nonesterified fatty acids (NEFA), whose serum levels are elevated in such patients, have been shown to interfere with cytokine production in vitro. In order to evaluate the effects of elevated NEFA levels on cytokine production in adipose tissue in vivo we used an 18-gauge open-flow microperfusion (OFM) catheter to induce local inflammation in the subcutaneous adipose tissue (SAT) of healthy volunteers and to sample interstitial fluid (IF) specifically from the inflamed tissue. In two crossover studies, nine subjects received either an intravenous lipid-heparin infusion to elevate circulating NEFA levels or saline over a period of 28 h. The former increased the circulating levels of triglycerides (TGs), NEFA, glucose, and insulin over the study period. NEFA effects on locally induced inflammation were estimated by measuring the levels of a panel adipokines in the OFM probe effluent. Interleukin-6 (IL-6), IL-8, tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein-1 (MCP-1) levels increased during the study period but were not affected by lipid-heparin infusion. In contrast, the level of IL-10, an anti-inflammatory cytokine, was significantly reduced during the final hour of lipid-heparin infusion (saline: 449.2 ± 105.9 vs. lipid-heparin: 65.4 ± 15.4 pg/ml; P = 0.02). These data provide the first in vivo evidence that elevated NEFA can modulate cytokine production by adipose tissue.