The interaction between metformin and physical activity on postprandial glucose and glucose kinetics: a randomised, clinical trial.

AIMS/HYPOTHESIS: The aim of this parallel-group, double-blinded (study personnel and participants), randomised clinical trial was to assess the interaction between metformin and exercise training on postprandial glucose in glucose-intolerant individuals. METHODS: Glucose-intolerant (2 h OGTT glucose of 7.8-11.0 mmol/l and/or HbA1c of 39-47 mmol/mol [5.7-6.5%] or glucose-lowering-medication naive type 2 diabetes), overweight/obese (BMI 25-42 kg/m2) individuals were randomly allocated to a placebo study group (PLA, n = 15) or a metformin study group (MET, n = 14), and underwent 3 experimental days: BASELINE (before randomisation), MEDICATION (after 3 weeks of metformin [2 g/day] or placebo treatment) and TRAINING (after 12 weeks of exercise training in combination with metformin/placebo treatment). Training consisted of supervised bicycle interval sessions with a mean intensity of 64% of Wattmax for 45 min, 4 times/week. The primary outcome was postprandial glucose (mean glucose concentration) during a mixed meal tolerance test (MMTT), which was assessed on each experimental day. For within-group differences, a group × time interaction was assessed using two-way repeated measures ANOVA. Between-group changes of the outcomes at different timepoints were compared using unpaired two-tailed Student's t tests. RESULTS: Postprandial glucose improved from BASELINE to TRAINING in both the PLA group and the MET group (∆PLA: -0.7 [95% CI -1.4, 0.0] mmol/l, p = 0.05 and ∆MET: -0.7 [-1.5, -0.0] mmol/l, p = 0.03), with no between-group difference (p = 0.92). In PLA, the entire reduction was seen from MEDICATION to TRAINING (-0.8 [-1.3, -0.1] mmol/l, p = 0.01). Conversely, in MET, the entire reduction was observed from BASELINE to MEDICATION (-0.9 [-1.6, -0.2] mmol/l, p = 0.01). The reductions in mean glucose concentration during the MMTT from BASELINE to TRAINING were dependent on differential time effects: in the PLA group, a decrease was observed at timepoint (t) = 120 min (p = 0.009), whereas in the MET group, a reduction occurred at t = 30 min (p < 0.001). V̇O2peak increased 15% (4.6 [3.3, 5.9] ml kg-1 min-1, p < 0.0001) from MEDICATION to TRAINING and body weight decreased (-4.0 [-5.2, -2.7] kg, p < 0.0001) from BASELINE to TRAINING, with no between-group differences (p = 0.7 and p = 0.5, respectively). CONCLUSIONS/INTERPRETATION: Metformin plus exercise training was not superior to exercise training alone in improving postprandial glucose. The differential time effects during the MMTT suggest an interaction between the two modalities. FUNDING: The Beckett foundation, A.P Møller Foundation, DDA, the Research Foundation of Rigshospitalet and Trygfonden. TRIAL REGISTRATION: ClinicalTrials.gov (NCT03316690). Graphical abstract.

Effects of an intensive lifestyle intervention on the underlying mechanisms of improved glycaemic control in individuals with type 2 diabetes: a secondary analysis of a randomised clinical trial.

AIMS/HYPOTHESIS: The aim was to investigate whether an intensive lifestyle intervention, with high volumes of exercise, improves beta cell function and to explore the role of low-grade inflammation and body weight. METHODS: This was a randomised, assessor-blinded, controlled trial. Ninety-eight individuals with type 2 diabetes (duration <10 years), BMI of 25-40 kg/m2, no use of insulin and taking fewer than three glucose-lowering medications were randomised (2:1) to either the standard care plus intensive lifestyle group or the standard care alone group. Standard care consisted of individual guidance on disease management, lifestyle advice and blinded regulation of medication following a pre-specified algorithm. The intensive lifestyle intervention consisted of aerobic exercise sessions that took place 5-6 times per week, combined with resistance exercise sessions 2-3 times per week, with a concomitant dietary intervention aiming for a BMI of 25 kg/m2. In this secondary analysis beta cell function was assessed from the 2 h OGTT-derived disposition index, which is defined as the product of the Matsuda and the insulinogenic indices. RESULTS: At baseline, individuals were 54.8 years (SD 8.9), 47% women, type 2 diabetes duration 5 years (IQR 3-8) and HbA1c was 49.3 mmol/mol (SD 9.2); 6.7% (SD 0.8). The intensive lifestyle group showed 40% greater improvement in the disposition index compared with the standard care group (ratio of geometric mean change [RGM] 1.40 [95% CI 1.01, 1.94]) from baseline to 12 months' follow-up. Plasma concentration of IL-1 receptor antagonist (IL-1ra) decreased 30% more in the intensive lifestyle group compared with the standard care group (RGM 0.70 [95% CI 0.58, 0.85]). Statistical single mediation analysis estimated that the intervention effect on the change in IL-1ra and the change in body weight explained to a similar extent (59%) the variance in the intervention effect on the disposition index. CONCLUSIONS/INTERPRETATION: Our findings show that incorporating an intensive lifestyle intervention, with high volumes of exercise, in individuals with type 2 diabetes has the potential to improve beta cell function, associated with a decrease in low-grade inflammation and/or body weight. TRIAL REGISTRATION: ClinicalTrials.gov NCT02417012 Graphical abstract.

GLP-1 secretion is regulated by IL-6 signalling: a randomised, placebo-controlled study.

AIMS/HYPOTHESIS: IL-6 is a cytokine with various effects on metabolism. In mice, IL-6 improved beta cell function and glucose homeostasis via upregulation of glucagon-like peptide 1 (GLP-1), and IL-6 release from muscle during exercise potentiated this beneficial increase in GLP-1. This study aimed to identify whether exercise-induced IL-6 has a similar effect in humans. METHODS: In a multicentre, double-blind clinical trial, we randomly assigned patients with type 2 diabetes or obesity to intravenous tocilizumab (an IL-6 receptor antagonist) 8 mg/kg every 4 weeks, oral sitagliptin (a dipeptidyl peptidase-4 inhibitor) 100 mg daily or double placebos (a placebo saline infusion every 4 weeks and a placebo pill once daily) during a 12 week training intervention. The primary endpoints were the difference in change of active GLP-1 response to an acute exercise bout and change in the AUC for the concentration-time curve of active GLP-1 during mixed meal tolerance tests at baseline and after the training intervention. RESULTS: Nineteen patients were allocated to tocilizumab, 17 to sitagliptin and 16 to placebos. During the acute exercise bout active GLP-1 levels were 26% lower with tocilizumab (multiplicative effect: 0.74 [95% CI 0.56, 0.98], p = 0.034) and 53% higher with sitagliptin (1.53 [1.15, 2.03], p = 0.004) compared with placebo. After the 12 week training intervention, the active GLP-1 AUC with sitagliptin was about twofold that with placebo (2.03 [1.56, 2.62]; p < 0.001), while GLP-1 AUC values showed a small non-significant decrease of 13% at 4 weeks after the last tocilizumab infusion (0.87 [0.67, 1.12]; p = 0.261). CONCLUSIONS/INTERPRETATION: IL-6 is implicated in the regulation of GLP-1 in humans. IL-6 receptor blockade lowered active GLP-1 levels in response to a meal and an acute exercise bout in a reversible manner, without lasting effects beyond IL-6 receptor blockade. TRIAL REGISTRATION: Clinicaltrials.gov NCT01073826. FUNDING: Danish National Research Foundation. Danish Council for Independent Research. Novo Nordisk Foundation. Danish Centre for Strategic Research in Type 2 Diabetes. European Foundation for the Study of Diabetes. Swiss National Research Foundation.

Reduced skeletal-muscle perfusion and impaired ATP release during hypoxia and exercise in individuals with type 2 diabetes.

AIMS/HYPOTHESIS: Plasma ATP is a potent vasodilator and is thought to play a role in the local regulation of blood flow. Type 2 diabetes is associated with reduced tissue perfusion. We aimed to examine whether individuals with type 2 diabetes have reduced plasma ATP concentrations compared with healthy control participants (case-control design). METHODS: We measured femoral arterial and venous plasma ATP levels with the intravascular microdialysis technique during normoxia, hypoxia and one-legged knee-extensor exercise (10 W and 30 W) in nine participants with type 2 diabetes and eight control participants. In addition, we infused acetylcholine (ACh), sodium nitroprusside (SNP) and ATP into the femoral artery to assess vascular function and ATP signalling. RESULTS: Individuals with type 2 diabetes had a lower leg blood flow (LBF; 2.9 ± 0.1 l/min) compared with the control participants (3.2 ± 0.1 l/min) during exercise (p < 0.05), in parallel with lower venous plasma ATP concentration (205 ± 35 vs 431 ± 72 nmol/l; p < 0.05). During systemic hypoxia, LBF increased from 0.35 ± 0.04 to 0.54 ± 0.06 l/min in control individuals, whereas it did not increase (0.25 ± 0.04 vs 0.31 ± 0.03 l/min) in the those with type 2 diabetes and was lower than in the control individuals (p < 0.05). Hypoxia increased venous plasma ATP levels in both groups (p < 0.05), but the increase was higher in control individuals (90 ± 26 nmol/l) compared to those with type 2 diabetes (18 ± 5 nmol/l). LBF and vascular conductance were lower during ATP (0.15 and 0.4 µmol min-1 [kg leg mass]-1) and ACh (100 µg min-1 [kg leg mass]-1) infusion in individuals with type 2 diabetes compared with the control participants (p < 0.05), whereas there was no difference during SNP infusion. CONCLUSIONS/INTERPRETATION: These findings demonstrate that individuals with type 2 diabetes have lower plasma ATP concentrations during exercise and hypoxia compared with control individuals, and this occurs in parallel with lower blood flow. Moreover, individuals with type 2 diabetes have a reduced vasodilatory response to infused ATP. These impairments in the ATP system are both likely to contribute to the reduced tissue perfusion associated with type 2 diabetes. TRIAL REGISTRATION: ClinicalTrials.gov NCT02001766.

Epicardial and pericardial adipose tissues are associated with reduced diastolic and systolic function in type 2 diabetes.

The aim of this study was to investigate the association of epicardial (EAT) and pericardial (PAT) adipose tissues with myocardial function in type 2 diabetes (T2D). EAT and PAT were measured by ultrasound in 770 patients with T2D and 234 age- and sex-matched non-diabetic controls. Echocardiography was performed, including tissue Doppler imaging and 2D speckle tracking. Patients with T2D versus controls had increased EAT (4.6 ± 1.8 mm vs. 3.4 ± 1.2 mm, P < 0.0001) and PAT (6.3 ± 2.8 mm vs. 5.3 ± 2.4 mm, P < 0.0001). EAT and PAT were associated with structural cardiac measures both in T2D patients and controls (all P < 0.043), but only in T2D patients with functional measures: PAT was associated with impaired global longitudinal strain [beta coefficient (SE)] [0.11% (0.04), P = 0.002], while EAT was associated with reduced diastolic function by lateral early diastolic myocardial velocity (e'lat ) [-0.31 (0.05) cm/s, P = 0.001], mitral inflow velocities: peak early (E)/peak atrial (A) ratio [-0.02 (0.01), P = 0.001] and lateral E/e'lat [0.36 (0.10), P < 0.001]. However, no interaction was found between diabetes status and PAT (P = 0.75) or EAT (P = 0.45). Adipose tissue in intimate relation to the myocardium is higher in patients with T2D versus controls and is associated with functional myocardial measures in T2D.

Type 2 diabetes remission 1 year after an intensive lifestyle intervention: A secondary analysis of a randomized clinical trial.

AIM: To investigate whether an intensive lifestyle intervention induces partial or complete type 2 diabetes (T2D) remission. MATERIALS AND METHODS: In a secondary analysis of a randomized, assessor-blinded, single-centre trial, people with non-insulin-dependent T2D (duration <10 years), were randomly assigned (2:1, stratified by sex, from April 2015 to August 2016) to a lifestyle intervention group (n = 64) or a standard care group (n = 34). The primary outcome was partial or complete T2D remission, defined as non-diabetic glycaemia with no glucose-lowering medication at the outcome assessments at both 12 and 24 months from baseline. All participants received standard care, with standardized, blinded, target-driven medical therapy during the initial 12 months. The lifestyle intervention included 5- to 6-weekly aerobic and combined aerobic and strength training sessions (30-60 minutes) and individual dietary plans aiming for body mass index ≤25 kg/m2 . No intervention was provided during the 12-month follow-up period. RESULTS: Of the 98 randomized participants, 93 completed follow-up (mean [SD] age 54.6 [8.9] years; 46 women [43%], mean [SD] baseline glycated haemoglobin 49.3 [9.3] mmol/mol). At follow-up, 23% of participants (n = 14) in the intervention and 7% (n = 2) in the standard care group met the criteria for any T2D remission (odds ratio [OR] 4.4, 95% confidence interval [CI] 0.8-21.4]; P = 0.08). Assuming participants lost to follow-up (n = 5) had relapsed, the OR for T2D remission was 4.4 (95% CI 1.0-19.8; P = 0.048). CONCLUSIONS: The statistically nonsignificant threefold increased remission rate of T2D in the lifestyle intervention group calls for further large-scale studies to understand how to implement sustainable lifestyle interventions among people with T2D.

Exercise-mediated improvement of depression in patients with gastro-esophageal junction cancer is linked to kynurenine metabolism.

Background: Exercise may improve depression in cancer patients, yet the molecular mechanism behind this protection is poorly understood. Here, we aimed to explore the link between exercise and regulation of kynurenine (Kyn) metabolism and inflammation in patients with operable gastro-esophageal junction (GEJ) cancer patients, who improved significantly in depression score with exercise training. Material and Methods: Fifty GEJ cancer patients were allocated to 12 weeks of supervised training twice weekly including interval-based aerobic exercise and resistance training, or standard care. Depression score was evaluated by HADS, and blood samples and muscle biopsies were collected for determination of Kyn metabolism and inflammation across the intervention. Results: Depression scores decreased by -1.3 points in the exercise group (p < 0.01), whereas no changes were observed in the control group. Plasma 3-hydroxykynurenine (HK), a Kyn metabolite giving rise to other neurotoxic metabolites, increased by 48% (p <0.001) in the control group, while exercise training attenuated this accumulation. The production of HK is induced by inflammation, and while we observed no differences in systemic pro-inflammatory cytokines, exercise training ameliorated the treatment-induced intramuscular inflammation. Moreover, exercise has been suggested to convert Kyn to the neuroprotective metabolite, kynurenic acid (KA), but despite marked functional and muscular exercise-mediated adaptations, we did not observe any enhancement of KA production and related enzyme expression in the muscles of GEJ cancer patients. Conclusion: Exercise training reduced symptoms of depression in patients with GEJ cancer, and this effect was associated with an exercise-dependent attenuation of the inflammation-induced conversion of Kyn to neurotoxic metabolites.

IL-10-specific autoantibodies predict major adverse cardiovascular events in kidney transplanted patients - a retrospective cohort study.

End-stage renal failure is associated with persistent systemic inflammation. The aim of this study was to investigate if systemic inflammation at the time of kidney transplantation is linked to poor graft survival, major adverse cardiovascular events (MACE), and increased mortality, and if these processes are modulated by naturally occurring cytokine-specific autoantibodies (c-aAbs), which have been shown to regulate cytokine activity in vitro. Serum levels of cytokines, high-sensitivity C-reactive protein (hsCRP) and c-aAbs specific for interleukin (IL)-1α, tumor necrosis factor (TNF)-α, IL-6, and IL-10 were measured at the time of transplantation in a retrospective cohort study of 619 kidney transplanted patients with a median follow-up of 4.9 years (range 1.2-8.2 years). Systemic inflammation was associated with all-cause mortality in simple and multiple Cox regression analyses. IL-10-specific c-aAbs were associated with MACE after transplantation, suggesting that IL-10 may be a protective factor. Similarly, patients with a history of MACE before transplantation had lower levels of TNF-α-specific c-aAbs, hence we hypothesized that TNF may be a risk factor of MACE. These findings support that pro-inflammatory activity before transplantation is a pathological driver of MACE and all-cause mortality after transplantation. This information adds to pretransplantation risk estimation in renal transplant candidates.

Sarcopenia and Postoperative Complication Risk in Gastrointestinal Surgical Oncology: A Meta-analysis.

OBJECTIVE: The aim of the study was to evaluate sarcopenia as a predictor of postoperative risk of major and total complications after surgery for gastrointestinal cancer. BACKGROUND: Sarcopenia is associated with poor survival in gastrointestinal cancer patients, but the role of sarcopenia as prognostic tool in surgical oncology has not been established, and no consensus exists regarding assessment and management of sarcopenic patients. METHODS: We performed a systematic search for citations in EMBASE, Web of Science, and PubMed from 2004 to January 31, 2017. Random effects meta-analyses were used to estimate the pooled risk ratio for postoperative complications by Clavien-Dindo grade (total complications: grade ≥2; major complications: grade ≥3) in patients with sarcopenia versus patients without sarcopenia. Stratified analyses were performed by sarcopenia criteria, cutoff level, assessment methods, study quality, cancer diagnosis, and "Enhanced Recovery After Surgery" care. RESULTS: Twenty-nine studies (n = 7176) were included with sarcopenia prevalence ranging between 12% and 78%. Preoperative incidence of sarcopenia was associated with increased risk of major complications (risk ratio 1.40; 95% confidence interval, 1.20-1.64; P < 0.001; I = 52%) and total complications (risk ratio 1.35; 95% confidence interval, 1.12-1.61; P = 0.001; I = 60%). Moderate heterogeneity was found for both meta-analyses. Subgroup analyses showed that sarcopenia remained a consistent risk factor across stratification by sarcopenia criteria, assessment methods, study quality, and diagnoses. CONCLUSIONS: Sarcopenia was associated with an increased risk of complications after gastrointestinal tumor resection, but lack of methodological consensus hampers the interpretation and clinical utilization of these findings. Combining assessment of muscle mass with measures of physical function may increase the prognostic value and accuracy in preoperative risk stratification.

Effect of 6 wk of high-intensity one-legged cycling on functional sympatholysis and ATP signaling in patients with heart failure.

Breathlessness during daily activities is the primary symptom in patients with heart failure (HF). Poor correlation between the hemodynamic parameters of left ventricular performance and perceived symptoms suggests that other factors, such as skeletal muscle function, play a role in determining exercise capacity. We investigated the effect of 6 wk of high-intensity, one-legged cycling (HIC; 8 × 4 at 90% one-legged cycling max) on 1) the ability to override sympathetic vasoconstriction (arterial infusion of tyramine) during one-legged knee-extensor exercise (KEE), 2) vascular function (arterial infusion of ACh, sodium nitroprusside, tyramine, and ATP), and 3) exercise capacity in HF patients with reduced ejection fraction ( n = 8) compared with healthy individuals ( n = 6). Arterial tyramine infusion lowered leg blood flow and leg vascular conductance at rest and during KEE before the training intervention in both groups ( P < 0.05) but not during KEE after the training intervention. There was no difference between groups. The peak vasodilatory response to ATP was blunted in HF patients ( P < 0.05), whereas there was no difference in ACh- and sodium nitroprusside-induced vasodilation between HF patients and healthy individuals. ACh-induced vasodilation increased in HF patients after the training intervention ( P < 0.05). HIC improved aerobic capacity in both groups ( P < 0.05), whereas only HF patients made improvements in the 6-min walking distance ( P < 0.05). These results suggest that exercise hyperemia and functional sympatholysis are not altered in HF patients and that functional sympatholysis is improved with HIC in both HF patients and healthy individuals. Moreover, these results suggest that the peak vasodilatory response to ATP is blunted in HF. NEW & NOTEWORTHY The ability to override sympathetic vasoconstrictor activity (by arterial tyramine infusion) during exercise is not different between heart failure patients and healthy individuals and is improved by high-intensity, one-legged cycling training. The peak vasodilatory response to ATP is reduced in heart failure patients.

Why prescribe exercise as therapy in type 2 diabetes? We have a pill for that!

The majority of T2D cases are preventable through a healthy lifestyle, leaving little room for questions that lifestyle should be the first line of defence in the fight against the development of T2D. However, when it comes to the clinical care of T2D, the potential efficacy of lifestyle is much less clear-cut, both in terms of impacting the pathological metabolic biomarkers of the disease, and long-term complications. A healthy diet, high leisure-time physical activity, and exercise are considered to be cornerstones albeit adjunct to drug therapy in the management of T2D. The prescription and effective implementation of structured exercise and other lifestyle interventions in the treatment of T2D have not been routinely used. In this article, we critically appraise and debate our reflections as to why exercise and physical activity may not have reached the status of a viable and effective treatment in the clinical care of T2D to the same extent as pharmaceutical drugs. We argue that the reason why exercise therapy is not utilized to a satisfactory degree is multifaceted and primarily relates to a "vicious cycle" with lack of proven efficacy on T2D complications and a lack of proven effectiveness on risk factors in the primary care of T2D. Furthermore, there is a lack of experimental research establishing the optimal dose of exercise. This precludes widespread and sustained implementation of physical activity and exercise in the clinical treatment of T2D will not succeed.

The effect on glycaemic control of low-volume high-intensity interval training versus endurance training in individuals with type 2 diabetes.

AIM: To evaluate whether high-intensity interval training (HIIT) with a lower time commitment can be as effective as endurance training (END) on glycaemic control, physical fitness and body composition in individuals with type 2 diabetes. MATERIALS AND METHODS: A total of 29 individuals with type 2 diabetes were allocated to control (CON; no training), END or HIIT groups. Training groups received 3 training sessions per week consisting of either 40 minutes of cycling at 50% of peak workload (END) or 10 1-minute intervals at 95% of peak workload interspersed with 1 minute of active recovery (HIIT). Glycaemic control (HbA1c, oral glucose tolerance test, 3-hour mixed meal tolerance test with double tracer technique and continuous glucose monitoring [CGM]), lipolysis, VO2 peak and body composition were evaluated before and after 11 weeks of intervention. RESULTS: Exercise training increased VO2 peak more in the HIIT group (20% ± 20%) compared with the END group (8% ± 9%) despite lower total energy expenditure and time usage during the training sessions. HIIT decreased whole body and android fat mass compared with the CON group. In addition, visceral fat mass, HbA1c, fasting glucose, postprandial glucose, glycaemic variability and HOMA-IR decreased after HIIT. The reduced postprandial glucose in the HIIT group was driven primarily by a lower rate of exogenous glucose appearance. In the CON group, postprandial lipolysis was augmented over the 11-week control period. CONCLUSIONS: Despite a ~45% lower training volume, HIIT resulted in similar or even better improvements in physical fitness, body composition and glycemic control compared to END. HIIT therefore appears to be an important time-efficient treatment for individuals with type 2 diabetes.

Glucose effectiveness, but not insulin sensitivity, is improved after short-term interval training in individuals with type 2 diabetes mellitus: a controlled, randomised, crossover trial.

AIMS/HYPOTHESIS: The role of glucose effectiveness (S G) in training-induced improvements in glucose metabolism in individuals with type 2 diabetes is unknown. The objectives and primary outcomes of this study were: (1) to assess the efficacy of interval walking training (IWT) and continuous walking training (CWT) on S G and insulin sensitivity (S I) in individuals with type 2 diabetes; and (2) to assess the association of changes in S G and S I with changes in glycaemic control. METHODS: Fourteen participants with type 2 diabetes underwent three trials (IWT, CWT and no training) in a crossover study. Exclusion criteria were exogenous insulin treatment, smoking, pregnancy, contraindications to structured physical activity and participation in recurrent training (>90 min/week). The trials were performed in a randomised order (computerised-generated randomisation). IWT and CWT consisted of ten supervised treadmill walking sessions, each lasting 60 min, over 2 weeks. IWT was performed as repeated cycles of 3 min slow walking and 3 min fast walking (aiming for 54% and 89% of [Formula: see text], respectively, which was measured during the last minute of each interval), and CWT was performed aiming for a moderate walking speed (73% of [Formula: see text]). A two-step (pancreatic and hyperinsulinaemic) hyperglycaemic clamp was implemented before and after each trial. All data were collected in a hospitalised setting. Neither participants nor assessors were blinded to the trial interventions. RESULTS: Thirteen individuals completed all procedures and were included in the analyses. IWT improved S G (mean ± SEM: 0.6 ± 0.1 mg kg-1 min-1, p < 0.05) but not S I (p > 0.05), whereas CWT matched for energy expenditure and time duration improved neither S G nor S I (both p > 0.05). Changes in S G, but not in S I, were associated with changes in mean (ß = -0.62 ± 0.23, r 2 = 0.17, p < 0.01) and maximum (ß = -1.18 ± 0.52, r 2 = 0.12, p < 0.05) glucose levels during 24 h continuous glucose monitoring. CONCLUSIONS/INTERPRETATION: Two weeks of IWT, but not CWT, improves S G but not S I in individuals with type 2 diabetes. Moreover, changes in S G are associated with changes in glycaemic control. Therefore, increased S G is likely an important mechanism by which training improves glycaemic control in individuals with type 2 diabetes. TRIAL REGISTRATION: ClinicalTrials.gov NCT02320526 FUNDING: CFAS is supported by a grant from TrygFonden. During the study period, the Centre of Inflammation and Metabolism (CIM) was supported by a grant from the Danish National Research Foundation (DNRF55). The study was further supported by grants from Diabetesforeningen, Augustinusfonden and Krista og Viggo Petersens Fond. CIM/CFAS is a member of DD2-the Danish Center for Strategic Research in Type 2 Diabetes (the Danish Council for Strategic Research, grant no. 09-067009 and 09-075724).

The effects of 2 weeks of interval vs continuous walking training on glycaemic control and whole-body oxidative stress in individuals with type 2 diabetes: a controlled, randomised, crossover trial.

AIMS/HYPOTHESIS: The aim of this study was to evaluate the effects of oxygen consumption-matched short-term interval walking training (IWT) vs continuous walking training (CWT) on glycaemic control, including glycaemic variability, in individuals with type 2 diabetes. We also assessed whether any training-induced improvements in glycaemic control were associated with systemic oxidative stress levels. METHODS: Participants (n = 14) with type 2 diabetes completed a crossover trial using three interventions (control intervention [CON], CWT and IWT), each lasting 2 weeks. These were performed in a randomised order (computerised generated randomisation) and separated by washout periods of 4 or 8 weeks after CON or training interventions, respectively. Training included ten supervised treadmill sessions, lasting 60 min/session, and was performed at the research facility. CWT was performed at moderate walking speed (75.6% ± 2.5% of walking peak oxygen consumption [[Formula: see text]]), while IWT was performed as alternating 3 min repetitions at slow (58.9% ± 2.0% [Formula: see text]) and fast (90.0% ± 3.6% [Formula: see text]) walking speed. Before and after each intervention, the following was assessed: 24 h continuous glucose monitoring (CGM) and urinary free 8-iso prostaglandin F2α (8-iso PGF2α; a marker for oxidative stress), physical fitness and body composition. Neither participants nor assessors were blinded to the interventions. RESULTS: No intervention-induced changes were seen in physical fitness or body composition. Compared with baseline, IWT reduced mean glucose levels non-significantly (-0.7 ± 0.3 mmol/l, p = 0.08) and significantly reduced maximum glucose levels (-1.8 ± 0.5 mmol/l, p = 0.04) and mean amplitude of glycaemic excursions (MAGE; -1.7 ± 0.4 mmol/l, p = 0.02), whereas no significant within-group changes were seen with CON or CWT. Although 8-iso PGF2α was associated with minimum glucose levels at baseline, no change in 8-iso PGF2α was seen with any intervention, nor were there any associations between changes in 8-iso PGF2α and changes in glycaemic control (p > 0.05 for all). No adverse effects were observed with any of the interventions. CONCLUSIONS/INTERPRETATION: Short-term IWT, but not CWT, improves CGM-derived measures of glycaemic control independent of changes in physical fitness and body composition in individuals with type 2 diabetes. Systemic oxidative stress levels are unaffected by short-term walking and changes in oxidative stress levels are not associated with changes in glycaemic control. TRIAL REGISTRATION: ClinicalTrials.gov NCT02320526 FUNDING : The Centre for Physical Activity Research (CFAS) is supported by a grant from TrygFonden. During the study period, the Centre of Inflammation and Metabolism (CIM) was supported by a grant from the Danish National Research Foundation (DNRF55). The study was further supported by grants from Diabetesforeningen, Augustinusfonden and Krista og Viggo Petersens Fond. CIM/CFAS is a member of the Danish Center for Strategic Research in Type 2 Diabetes (DD2; the Danish Council for Strategic Research, grant no. 09-067009 and 09-075724). MR-L was supported by a post-doctoral grant from the Danish Diabetes Academy supported by the Novo Nordisk Foundation.

Effect of a 2-year home-based endurance training intervention on physiological function and PSA doubling time in prostate cancer patients.

AIM: Physical activity after prostate cancer diagnosis has been shown to reduce the risk of disease progression. Here, we aimed to evaluate the effect of a 2-year home-based endurance training intervention on body composition, biomarkers levels, and prostate-specific antigen (PSA) doubling time as a surrogate end-point for progressing disease. METHODS: Out-clinic patients with either biochemical recurrence following radical prostatectomy or patients managed on active surveillance were randomized to either 24 months (3 times/week) of home-based endurance training or usual care. Aerobic fitness, body composition, insulin sensitivity, and biomarkers were measured at 0, 6, and 24 months of intervention. PSA doubling time (PSADT) was calculated based on monthly PSA measurements. RESULTS: Twenty-five patients were enrolled, and 19 patients completed the study. PSADT increased in the training group from 28 to 76 months (p < 0.05) during the first 6 months and was correlated with changes in VO2max (p < 0.01, r (2) = 0.41). The training group lost 3.6 ± 1.0 kg (p < 0.05) exclusively as fat mass, yet the changes in body composition were not associated with the increased PSADT. The training group showed significant improvements in plasma triglycerides, adiponectin, IGF-1, IGFBP-1, and fasting glucose levels, but no changes in insulin sensitivity (measured as Matsuda index), testosterone, cholesterols, fasting insulin, plasma TNF-alpha, IL-6, or leptin levels. The control group showed no changes in any of the evaluated parameters across the 2-year intervention. CONCLUSION: In this small randomized controlled trial, we found that improvements in fitness levels correlated with increasing PSADT, suggesting a link between training and disease progression.

Skeletal muscle as a gene regulatory endocrine organ.

PURPOSE OF REVIEW: Skeletal muscle is gaining increased attention as an endocrine organ. Recently, novel myokines and new effects of already established myokines have been identified. The objective of this review is to give an update on the recent advances in the field. RECENT FINDINGS: Several hundred putative myokines have been described, some of which are induced by contraction and differentially regulated between healthy and metabolically diseased individuals. Interleukin-6 (IL-6) is the prototype myokine, which was identified as a muscle-derived cytokine 15 years ago. Recently, IL-6 has been linked to ß-cell survival and inhibition of cancer-cell growth. Moreover, trans-signaling appears to determine whether IL-6 acts as a proinflammatory or an anti-inflammatory cytokine. Irisin has been shown to be a secreted myokine, which contribute to circulating concentrations dependent on training status. IL-15 has been established as a cytokine mediating cross-talk between skeletal muscle and skin tissue, and decorin has been characterized as a contraction-induced myokine which apparently is differentially regulated between healthy and dysglycemic individuals. SUMMARY: Skeletal muscle is an endocrine organ which, by the release of myokines, may influence metabolism in virtually all organs in the body. This knowledge may potentially open up for the possibility of designing new drugs that mimic the effects of myokine signaling.

Glucose tolerance is associated with differential expression of microRNAs in skeletal muscle: results from studies of twins with and without type 2 diabetes.

AIMS/HYPOTHESIS: We aimed to identify microRNAs (miRNAs) associated with type 2 diabetes and risk of developing the disease in skeletal muscle biopsies from phenotypically well-characterised twins. METHODS: We measured muscle miRNA levels in monozygotic (MZ) twins discordant for type 2 diabetes using arrays. Further investigations of selected miRNAs included target prediction, pathway analysis, silencing in cells and association analyses in a separate cohort of 164 non-diabetic MZ and dizygotic twins. The effects of elevated glucose and insulin levels on miRNA expression were examined, and the effect of low birthweight (LBW) was studied in rats. RESULTS: We identified 20 miRNAs that were downregulated in MZ twins with diabetes compared with their non-diabetic co-twins. Differences for members of the miR-15 family (miR-15b and miR-16) were the most statistically significant, and these miRNAs were predicted to influence insulin signalling. Indeed, miR-15b and miR-16 levels were associated with levels of key insulin signalling proteins, miR-15b was associated with the insulin receptor in non-diabetic twins and knockdown of miR-15b/miR-16 in myocytes changed the levels of insulin signalling proteins. LBW in twins and undernutrition during pregnancy in rats were, in contrast to overt type 2 diabetes, associated with increased expression of miR-15b and/or miR-16. Elevated glucose and insulin suppressed miR-16 expression in vitro. CONCLUSIONS: Type 2 diabetes is associated with non-genetic downregulation of several miRNAs in skeletal muscle including miR-15b and miR-16, potentially targeting insulin signalling. The paradoxical findings in twins with overt diabetes and twins at increased risk of the disease underscore the complexity of the regulation of muscle insulin signalling in glucose homeostasis.

Type 2 diabetes alters metabolic and transcriptional signatures of glucose and amino acid metabolism during exercise and recovery.

AIMS/HYPOTHESIS: The therapeutic benefit of physical activity to prevent and treat type 2 diabetes is commonly accepted. However, the impact of the disease on the acute metabolic response is less clear. To this end, we investigated the effect of type 2 diabetes on exercise-induced plasma metabolite changes and the muscular transcriptional response using a complementary metabolomics/transcriptomics approach. METHODS: We analysed 139 plasma metabolites and hormones at nine time points, and whole genome expression in skeletal muscle at three time points, during a 60 min bicycle ergometer exercise and a 180 min recovery phase in type 2 diabetic patients and healthy controls matched for age, percentage body fat and maximal oxygen consumption (VO2). RESULTS: Pathway analysis of differentially regulated genes upon exercise revealed upregulation of regulators of GLUT4 (SLC2A4RG, FLOT1, EXOC7, RAB13, RABGAP1 and CBLB), glycolysis (HK2, PFKFB1, PFKFB3, PFKM, FBP2 and LDHA) and insulin signal mediators in diabetic participants compared with controls. Notably, diabetic participants had normalised rates of lactate and insulin levels, and of glucose appearance and disappearance, after exercise. They also showed an exercise-induced compensatory regulation of genes involved in biosynthesis and metabolism of amino acids (PSPH, GATM, NOS1 and GLDC), which responded to differences in the amino acid profile (consistently lower plasma levels of glycine, cysteine and arginine). Markers of fat oxidation (acylcarnitines) and lipolysis (glycerol) did not indicate impaired metabolic flexibility during exercise in diabetic participants. CONCLUSIONS/INTERPRETATION: Type 2 diabetic individuals showed specific exercise-regulated gene expression. These data provide novel insight into potential mechanisms to ameliorate the disturbed glucose and amino acid metabolism associated with type 2 diabetes.

Mechanisms behind the superior effects of interval vs continuous training on glycaemic control in individuals with type 2 diabetes: a randomised controlled trial.

AIMS/HYPOTHESIS: By use of a parallel and partly crossover randomised, controlled trial design we sought to elucidate the underlying mechanisms behind the advantageous effects of interval walking training (IWT) compared with continuous walking training (CWT) on glycaemic control in individuals with type 2 diabetes. We hypothesised that IWT, more than CWT, would improve insulin sensitivity including skeletal muscle insulin signalling, insulin secretion and disposition index (DI). METHODS: By simple randomisation (sequentially numbered, opaque sealed envelopes), eligible individuals (diagnosed with type 2 diabetes, no exogenous insulin treatment) were allocated to three groups: a control group (CON, n = 8), an IWT group (n = 12) and an energy expenditure-matched CWT group (n = 12). Training groups were prescribed free-living training, five sessions per week (60 min/session). A three-stage hyperglycaemic clamp, including glucose isotope tracers and skeletal muscle biopsies, was performed before and after a 4 month intervention in a hospitalised setting. No blinding was performed. RESULTS: The improved glycaemic control, which was only seen in the IWT group, was consistent with IWT-induced increases in insulin sensitivity index (49.8 ± 14.6%; p < 0.001), peripheral glucose disposal (14.5 ± 4.9%; p < 0.05) and DI (66.2 ± 21.8%; p < 0.001), with no changes in the CWT or CON group. Moreover, only IWT improved insulin signalling in skeletal muscle via increased insulin-stimulated phosphorylation of AS160 (29.0 ± 10.8%; p < 0.05). No changes were seen in insulin secretion during hyperglycaemia alone, hyperglycaemia + glucagon-like peptide 1 infusion or arginine injection. CONCLUSIONS/INTERPRETATION: IWT maintains insulin secretion and improves insulin sensitivity and DI, in contrast to energy expenditure-matched CWT. These results suggest that training with alternating intensity, and not just training volume and mean intensity, is a key determinant of changes in whole body glucose disposal in individuals with type 2 diabetes. TRIAL REGISTRATION: ClinicalTrials (NCT01234155).