Uncovering bone-muscle-fat interaction in patients with type 2 diabetes: effects of acute and chronic exercise

INTERVENTION: The study involves three main parts. 1) screening and baseline assessments related to bone, muscle and body composition health, 2) acute high intensity interval exercise (HIIE) and 3) chronic exercise training (10‐weeks). For all acute HIIE and exercise training visits, participants will be supervised by an Exercise Physiologists in a 1:1 or 1:2 format. All the assessments and exercise training will be conducted face‐to‐face at Victoria University. Acute sessions at baseline will be conducted within 7 days of screening, acute sessions following 4 and 10 weeks of exercise training will be conducted after 72 hours of the last exercise training session. EFFECTS OF ACUTE EXERCISE We will examine the effects of acute high intensity interval exercise (HIIE) on markers of bone, muscle and fat metabolism as well as changes in markers of metabolic and cardiovascular (CV) risk (glucose, lipids, inflammation etc). This (identical) acute HIIE session will also be performed following 4 and 10 weeks of HIIE training, with each session taking approximately 4 hours. Should the participant decide to complete an OGTT at the end of the 1st acute session, this will take the duration to 7 hours total. Blood sampling will be taken before exercise, immediately following exercise, and up to 180 min post‐exercise. Urine samples will be taken before and following exercise. Participants can elect to have none, one (at rest) or si X(1 at rest and 1 following each acute exercise session) muscle and adipose tissue biopsies. Muscle will be analysed for protein degradation and protein synthesis pathways. Other novel markers associated with muscle, bone and fat health may also be assessed. Twenty‐four hours prior to the acute HIIE session participants will be asked to refrain from any for CONDITION: Metabolic and Endocrine ‐ Diabetes Musculoskeletal ‐ Other muscular and skeletal disorders Type 2 Diabetes; ; Type 2 Diabetes INCLUSION CRITERIA: Males and females aged over 18years with type 2 diabetes. Postmenopausal Females will be required to be a minimum of 12 months post menopause. PRIMARY OUTCOME: Changes in bone remodelling markers. Assessed as a composite primary outcome by: osteocalcin, C‐terminal telopeptide of type 1 collagenand lipocalin 2[Baseline and immediately following the 30min acute HIE session 0mins, 30mins, 60mins, 120mins (primary endpoint) and 180 mins post exercise and for the chronic training the timepoints are baseline and 4 and 10 weeks post exercise training] Changes in insulin sensitivity. Assessed as a composite primary outcome by: fasting blood glucose, oral glucose tolerance test (OGTT), Homeostatic Model Assessment for Insulin Resistance (HOMA‐IR) and HbA1c[Baseline and immediately following the 30min acute HIE session 0mins, 30mins, 60mins, 120mins (primary endpoint) and 180 mins post exercise, and for the chronic training the timepoints are baseline and 4 and 10 weeks post exercise training (or control)] Changes in sex hormone levels. Assessed as a composite primary outcome by: testosterone, estradiol, sex hormone binding globulin, follicular stimulating hormone, luteinising hormone.; ; Analysed through blood ; Blood sampling and analysis procedure:; Blood Sampling: All blood samples will be collected into EDTA and SST vacutainers for the appropriate collection of red blood cells, serum and plasma. Following 10 mins clotting time, samples will be centrifuged for 10 mins at 4C and immediately transferred to long‐term storage at ‐80C in 1‐2 mL aliquots for later analysis. To analyse, blood samples will undergo quantification of an array of relevant assay protocols to assess biomarkers such as hormones (androgens: total testosterone, dihydrotestosterone(DHT), estradiol, sex hormone binding globulin (SHBG), luteinizing hormone (LH), follicular stimulating hormone (FSH), cortisol, parathyroid hormone), or those related to glucose tolerance, muscle and metabolic metabolism, bone remodelling and cardiometabolic risk factors. ; Blood Analyses: Blood samples will undergo quantification of an array of biomarkers related to bone remodelling, muscle and metabolic metabolism and cardiometabolic risk factors. Some of these analyses will include hormones (testosterone, estradiol, LH, FSH, SHBG, cortisol), lipids, glucose and insulin, inflammation markers and potentially other cardiovascular or health markers. Other factors involved in the bone‐muscle‐adipose crosstalk or, involved in bone, muscle or cardiovascular health will also be considered. These analyses may occur within our research group, with our collaborators or with future collaborators. However, all samples are coded, and identifiable information will not be shared.[Baseline and immediately following the 30min acute HIE session 0mins, 30mins, 60mins, 120mins (primary endpoint) and 180 mins post exercise, and for the chronic training the timepoints are baseline and 4 and 10 weeks post exercise training] SECONDARY OUTCOME: Body composition assessed via Dual‐energy X‐ray absorptiometry (DXA). This will be a composite assessment of: whole body composition, bone mineral density as well as percentage of lean body mass and fat mass.[baseline and following 4 and 10 weeks of exercise training (or control)] Change in aerobic capacity (VO2Peak) from baseline to after chronic exercise training: ; Participants will complete three graded exercise tests (GXTs), one at each baseline visit and one during post assessments (weeks 4 and 10) for the determination of peak oxygen consumption (VO2Peak). As participants are not familiar with the GXT before starting the exercise training program, the first GXT shows high variability, which leads to unreliable baseline fitness estimates. A second GXT before starting the training program would provide much more stable results that can be used to personalise the exercise intensity of each participant reliably. VO2Peak will be assessed on a cycle ergometer with the initial intensity beginning at 10‐30 Watts and increasing by 10‐30W×min‐1 according to participant ability. Participants will be monitored by 12‐lead electrocardiogram (ECG; Mortara, X‐Scribe II, Milwaukee, WI). VO2 for each 15‐s interval will be measured by gas exchange analysis (BreezeEx, version 3.02, Medical Graphics Corp.) with routine calibration of gas concentrations and flow prior to each test. The test will be terminated according to participants’ self‐reported fatigue perception reaching a pre‐determined level (using the Borg scale, Rating of Perceived Exertion equals 17) or clinical signs or symptoms. Blood pressure will be monitored at baseline, regular intervals (each stage) and post exercise using a manual sphygmomanometer, and heart rate will be monitored via the 12‐lead ECG. [baseline and following 4 and 10 weeks of exercise training (or control)] Change in physical performance test score (combined score including performance in timed up and go, gait velocity, stair climbing, stair descending) from baseline to after chronic exercise training. ; Participants will complete a Physical Performance Test (PPT), adapted from Levinger et al. The PPT includes four functional mobility tasks; 1) gait velocity; 2) timed up and go; 3) stair climbing power (SCP) and 4) stair ascending and descending. All tests will be scored in time (seconds) and completed three times. The fastest times will be recorded for each test. Gait velocity will be measured using 3 different protocols with reduced physical function determined as <80 cm/sec: ; 1. Protocol one: Participants walk at their normal pace over a 4m track; ; 2. Protocol two: Participants walk at their normal pace over an 8m track, with metres 2‐6 being recorded (seconds) to exclude acceleration and deceleration; ; 3. Protocol three: Participants will be instructed to walk as fast as they can without running over an 8m track. Metres 2‐6 will be recorded to exclude acceleration and deceleration. ; The timed up and go test: A simple performance‐based assessment, requiring minimal equipment including; standard arm chair ( 46cm), 3‐meter walkway with floor mark and stopwatch (time, seconds). It is performed as time (seconds) taken to rise from a seated position, walk 3 meters, turn, walk back to the chair and then sit. ; The SCP: Will consist of a rapid ascent of 10 stairs, where; ; SCP = body weight (kg) X9.8ms‐2 Xstep height (m) Xnumber of steps Xtime ‐1 (s‐1) ; The stair descent: Will be time to safely descend 10 stairs. The rest between the ascent and descent will be 45 s. Participants will undergo four attempts on each task and the best time recorded for each. The PPT score will be the sum of the fastest times recorded for each test. ; [baseline and following 4 and 10 weeks of exercise training (or control)] Changes in grip strength ; Grip strength will be measured using a hand dynamometer (TTM Advanced, HMG Direct, Australia). A result of <20 kg for females and <30 kgs for males will identify low muscle strength. Participants will undergo three tests on both hands, with the highest measure being recorded. ; [Baseline and following 4 and 10 weeks exercise training (or control)] Changes in muscle and fat tissue quality ; ; Assessed by tissue biopsies: ; Biopsy procedure ; If the participant consents to a muscle biopsy, the muscle sample/s (1 or 6) will be taken from the vastus lateralis under local anaesthesia by an experienced medical practitioner using a percutaneous needle biopsy technique, modified to include suction. Excised tissue will be snap‐frozen in liquid nitrogen and stored at ‐80?C for later analysis. Proteins involved in muscle degradation and hypertrophy (i.e. anabolic and catabolic pathways; ubiquitin‐proteasome, autophagy‐lysosome and caspase‐3‐mediated proteolytic pathways) as well as glucose uptake will be assessed, as we previously performed .[Baseline and immediately following the 30min acute HIE session 0mins, 30mins, 60mins, 120mins (primary endpoint) and 180 mins post exercise, and for the chronic training the timepoints are baseline and 4 and 10 weeks post exercise training] Changes in muscle tissue health. Assessed as a composite primary outcome by: proteins associated with muscle hypertrophy/degradation (mammalian target of rapamycin (mTOR), Ak strain transforming (Akt), extracellular signal‐regulated kinase 1/2 (ERK1/2)).[baseline and following 4 and 10 weeks of exercise training (or control)] Participants will perform a one maximal repetition (1RM) test on a leg press. This will be performed twice with the first visit serving as familiarisation. 1RM is defined as the heaviest weight lifted once, with proper technique and without compensatory movements[baseline and following 4 and 10 weeks of exercise training (or control)] Vascular stiffness, assessed via applanation tonometry (sphygmocor)[baseline and following 4 and 10 weeks of exercise training (or control)]