Exercise, Gut Microbiota and Type 2 Diabetes (Ex-GM-T2D)

The Effects of Regular Exercise on Gut Microbiota Composition in Individuals with Type 2 Diabetes

This randomized, parallel, controlled study, will investigate the effect of regular exercise on GM composition, inflammatory status, and insulin sensitivity, in the progression from normal glucose tolerance (NGT), to prediabetes (pre-D), to type 2 diabetes (T2D). Following baseline assessment of glucose tolerance, the participants will be randomly assigned to either a 12-week, thrice-weekly exercise training program followed by 4 weeks of detraining, or will remain sedentary for the 16-week intervention. Thus, the six study groups will be: 1) NGT group (NGT), NGT individuals - no exercise, 2) NGT exercise group (NGT+Ex), NGT individuals that will participate in training and detraining, 3) pre-D group (pre-D), pre-D individuals - no exercise, 4) pre-D exercise group (Pre-D+Ex), pre-D individuals that will participate in training and detraining, 5) T2D group (T2D), T2D individuals - no exercise, and 6) T2D exercise group (T2D+Ex), T2D individuals that will participate in training and detraining. Assessment of physiological measures, anthropometric characteristics, body composition, glucose tolerance, insulin sensitivity, complete blood count, lipidemic profile, GM composition, inflammatory status, oxidative stress, and muscle performance, will be conducted before and following 12 weeks of the exercise training intervention and following 4 weeks of detraining for all participants.

Study Overview

• Status: Recruiting
• Conditions: Type 2 Diabetes
• Intervention / Treatment: Other: Regular exercise; Other: Control comparator

Detailed Description

Type 2 diabetes is a global metabolic epidemic and a major global health threat. In 2021, 537 million adults aged 20-79 years worldwide had diabetes. T2D, is related with life threatening microvascular and macrovascular health complications that contribute tremendously to the burden of mortality and disability worldwide. T2D is defined by fasting hyperglycemia which is largely secondary to inadequate action of insulin. T2D is usually preceded by a state of intermediate hyperglycemia or Pre-D, which is characterized by impaired fasting glucose (IFG), impaired glucose tolerance (IGT), or both, and greatly increases the risk for T2D. In T2D, although insulin levels are normal or high, tissues such as liver, skeletal muscle, and adipose tissue become resistant to insulin resulting in high levels of blood glucose. T2D is associated with a systemic inflammatory response which seems to be an independent risk factor for the development of T2D. Additionally, individuals with T2D tend to have a more oxidative internal environment than healthy subjects. Hyperglycemia-induced oxidative stress has been found to affect the insulin signaling cascade and decrease GLUT4 gene transcription and also alter mitochondrial activity. T2D pathophysiology has also been associated with GM composition. Dysbiosis of GM is suggested to have a central role in the pathogenesis of insulin resistance and T2D through several mechanisms.

The important role of regular exercise for the prevention and treatment of T2D has been established. Most benefits of exercise on T2D management and prevention are realized through the adaptations to skeletal muscle which in turn induce acute and chronic improvements in insulin action. Exercise also exerts anti-inflammatory effects. Emerged evidence suggests that exercise may also favorably affect T2D by improving GM composition. The most promising effect of regular exercise is the alteration of GM towards a healthier microbial composition by producing a more diverse GM, decreasing pathogenic bacterial communities and increasing SCFAs-producing bacteria. However, the impact of exercise on the GM structure and function of T2D individuals is poorly understood, as only a limited number of studies exist in this area, so far.

According to a preliminary power analysis (a probability error of 0.05 and a statistical power of 80%), a sample size of 8-10 participants/group was considered appropriate to detect statistically meaningful changes between trials. Thus, ≥60 middle-aged individuals will be assessed for eligibility to participate in the study. The study will be conducted in a parallel, randomized, controlled design. The participants, will be primarily informed of the study procedures, as well as the benefits and possible risks, and they will also sign an informed consent form for participation in the study. All eligible individuals will provide blood samples for the determination of fasting blood glucose, glycosylated hemoglobin (HbA1c), and fasting plasma insulin, and will take an oral glucose tolerance test (OGTT) to determine their glycemic profile, according to which, they will be characterized as normal glucose tolerance (NGT) individuals, or pre-diabetes (pre-D) individuals, or type 2 diabetes (T2D) individuals. Physical activity levels will also be assessed through the International Physical Activity Questionnaire (IPAQ). Afterwards, the participants of each glucose tolerance stage will be randomly assigned to either the 12 weeks of regular combined aerobic and resistance exercise according to the guidelines for pre-D and T2D individuals, or remain sedentary for 12 weeks. Thus, six intervention groups will be as follows: i) NGT group (NGTG), NGT individuals - no exercise, ii) NGT exercise group (NGTG+Ex), NGT individuals that will participate in training and detraining, iii) pre-D group (pre-DG), pre-D individuals - no exercise, iv) pre-D exercise group (Pre-DG+Ex), pre-D individuals that will participate in training and detraining, v) T2D group (T2DG), T2D individuals - no exercise, and vi) T2D exercise group (T2DG+Ex), T2D individuals that will participate in training and detraining. Randomization of the conditions will be done by a software generating random integers available on the internet (Random.org).

Baseline measurements will take place at the Laboratory of Biochemistry, Physiology and Nutrition of Exercise (SmArT Lab), Department of Physical Education and Sports, University of Thessaly: physiological measures (resting heart rate, resting systolic and diastolic blood pressure, resting metabolic rate), anthropometric characteristics (body height, body mass, body mass index), body composition (amount of body fat, lean body mass, fat mass, bone density), muscle performance [aerobic capacity (VO2max), isokinetic strength of the lower extremities (isometric, concentric and eccentric torque of the knee extensors and knee flexors), handgrip strength, muscle power (countermovement jump)]. Additionally, the participants will provide feces for the determination of GM composition and GM metabolites [short chain fatty acids (SCFAs)], as well as blood samples for the determination of complete blood count (CBC), systemic inflammation [tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), C-reactive protein (CRP), zonulin, lipopolysaccharides-binding protein (LBP)], blood redox status [total antioxidant capacity (TAC), catalase (CAT), protein carbonyls (PC), reduced glutathione (GSH), oxidized glutathione (GSSG), GSH/GSSG ratio, malondialdehyde (MDA), uric acid, bilirubin], and lipid profile [total cholesterol (CHO-T), low density lipoprotein (LDL), high density lipoprotein (HDL), triglycerides (TG)]. In addition, the participants will record their diet via a 7-days recall before their participation in the first experimental condition, and dietary data will be analyzed. All of the above measurements will be repeated following the 12-weeks of exercise intervention, as well as following the 4-weeks of detraining period. The participants that will be allocated into the regular exercise, except for VO2max, they will further undergo estimation of maximal strength of the main muscle groups for the determination of intensity of each participant's exercise program; aerobic capacity and muscle strength determination will also be repeated after four weeks of the regular exercise for the necessary intensity adjustments of the exercise program.

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Athanasios Z Jamurtas, PhD; Email: ajamurt@pe.uth.gr
• Study Contact Backup: Name: Chariklia K. Deli, PhD; Phone Number: +302431047011; Email: delixar@pe.uth.gr

Study Locations

• Greece
  • Tríkala, Greece, 42100
    • Recruiting
    • Department of Physical Education and Sport Science, Uninersity of Thessaly
    • Contact: Chariklia K. Deli, Phd; Email: delixar@pe.uth.gr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Age between 45 and 65 years old
• Sedentary lifestyle or insufficient daily physical activity according to guidelines for T2D
• Abstinence of anti-inflammatory drugs and/or antibiotics and/or dietary supplements that could affect GM composition before the study (>3 months)
• No other chronic diseases and/or musculoskeletal injuries (>6 months)

Exclusion Criteria:

• Age <45 years or >65 years
• Physically active individuals
• Consumption of anti-inflammatory drugs and/or antibiotics and/or dietary supplements that could affect GM composition before the study (<3 months)
• Other chronic diseases ot recent history of musculoskeletal injury (<6 months)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Screening
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

6

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: NGT - Exercise; Regular exercise for 12 weeks and detraining for 4 weeks	Other: Regular exercise; Participants will perform regular exercise training for 12 weeks, followed by 4 weeks of detraining.
Active Comparator: NGT - Control comparator; Sedentary behavior for 16 weeks	Other: Control comparator; Participants will remain sedentary throughout the 16-weeks intervention period.
Experimental: Pre-D - Exercise; Regular exercise for 12 weeks and detraining for 4 weeks	Other: Regular exercise; Participants will perform regular exercise training for 12 weeks, followed by 4 weeks of detraining.
Active Comparator: Pre-D - Control comparator; Sedentary behavior for 16 weeks	Other: Control comparator; Participants will remain sedentary throughout the 16-weeks intervention period.
Experimental: T2D - Exercise; Regular exercise for 12 weeks and detraining for 4 weeks	Other: Regular exercise; Participants will perform regular exercise training for 12 weeks, followed by 4 weeks of detraining.
Active Comparator: T2D - Control comparator; Sedentary behavior for 16 weeks	Other: Control comparator; Participants will remain sedentary throughout the 16-weeks intervention period.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in gut microbiota composition	Gut microbiota composition will be assessed in feces via Next generation sequencing	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in butyrate	Butyrate will be assessed in feces via HPLC/MS	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in propionate	Propionate will be assessed in feces via HPLC/MS	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in acetate	Acetate will be assessed in feces via HPLC/MS	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in White blood cells (WBC)	WBC will be assessed in whole blood via hematological analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in Lymphocytes (LYM)	LYM will be assessed in whole blood via hematological analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in Monocytes (MON)	MON will be assessed in whole blood via hematological analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in Granulocytes (GRA)	GRA will be assessed in whole blood via hematological analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in percent Lymphocytes (LYM%)	LYM% will be assessed in whole blood via hematological analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in percent Monocytes (MON%)	MON% will be assessed in whole blood via hematological analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in percent Granulocytes (GRA%)	GRA% will be assessed in whole blood via hematological analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in Red blood cells (RBC)	RBC will be assessed in whole blood via hematological analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in Hemoglobin (HGB)	HGB will be assessed in whole blood via hematological analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in Hematocrit (HCT)	HCT will be assessed in whole blood via hematological analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in Mean corpuscular volume (MCV)	MCV will be assessed in whole blood via hematological analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in Mean corpuscular hemoglobin (MCH)	MCH will be assessed in whole blood via hematological analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in Mean corpuscular hemoglobin concentration (MCHC)	MCHC will be assessed in whole blood via hematological analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in Red cell distribution width (RDW)	RDW will be assessed in whole blood via hematological analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in Platelets (PLT)	PLT will be assessed in whole blood via hematological analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in Mean platelets volume (MPV)	MPV will be assessed in whole blood via hematological analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in Plateletcrit (PCT)	PCT will be assessed in whole blood via hematological analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in Plateletcrit distribution width (PDW)	PDW will be assessed in whole blood via hematological analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in TNF-α concentration	TNF-α concentration will be assessed in serum via ELISA	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in IL-6 concentration	IL-6 concentration will be assessed in serum via ELISA	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in high-sensitivity C-reactive protein concentration	C-reactive protein concentration will be assessed in serum via ELISA	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in lipopolysacharides-binding protein (LBP) concentration	LBP concentration will be assessed in serum via ELISA	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in zonulin concentration	Zonulin concentration will be assessed in serum and in feces via ELISA	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in protein carbonyls (PC) concentration	PC concentration will be assessed in plasma via a spectrophotometer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in malondialdehyde (MDA) concentration	MDA concentration will be assessed in plasma via HPLC	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in reduced glutathione (GSH) concentration	GSH concentration will be assessed in red blood cells lycate via a spectrophotometer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in oxidized glutathione (GSSG) concentration	GSSG concentration will be assessed in red blood cells lycate via a spectrophotometer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in GSH/GSSG ratio	GSH/GSSG ratio will be calculated by dividing GSH concentration with GSSG concentration	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in catalase concentration	Catalase concentration will be assessed in red blood cells lycate via a spectrophotometer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in total antioxidant capacity (TAC)	TAC will be assessed in red blood cells lycate via a spectrophotometer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in uric acid concentration	Uric acid concentration will be assessed in serum via a biochemical analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in bilirubin concentration	Bilirubin concentration will be assessed in serum via a biochemical analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in glycosylated hemoblobin (HbA1c) concentration	HbA1c concentration will be assessed in whole blood via a HbA1c analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in fasting plasma glucose	Fasting plasma glucose will be assessed in plasma via a biochemical analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in fasting plasma insulin	Fasting plasma insulin will be assessed in plasma via a biochemical analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in insulin resistance	Insulin resistance will be calulated via the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) index	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in insulin resistance - Oral glucose tolerance test (OGTT)	OGTT will be assessed via the estimation of 2-h plasma glucose following oral glucose consumption	Pre, 30 minutes post-, 60 minutes post-, 90 minutes post-,120 minutes post-glucose consumption
Changes in total cholesterol (CHOL-T)	CHOL-T will be assessed via a biochemical analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in low-density lipoprotein cholesterol (LDL-C)	LDL-C will be assessed via a biochemical analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in high-density lipoprotein cholesterol (HDL-C)	HDL-C will be assessed via a biochemical analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in triglycerides (TG)	TG will be assessed via a biochemical analyzer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in countermovement jump height (CMJ)	CMJ height will be measured via an optical system	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in isokinetic strength of knee extensors and knee flexors	Isometric, concentric and eccentric peak torque of the knee extensors and knee flexors of both limbs will be assessed via an isokinetic dynamometer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in handgrip strength	Handgrip strength will be assessed via a handgrip dynamometer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in resting heart rate (HR)	Resting HR will be assessed via a HR monitor	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in resting systolic (SBP) and diastolic blood pressure (DBP)	Resting SBP and DBP will be assessed via a manual sphygmomanometer	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in resting metabolic rate (RMR)	RMR will be assessed via indirect calorimetry	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in body mass (BM)	BM will be assessed via a stadiometer-Beam balance	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in body height	Body height will be assessed via a stadiometer-Beam balance	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in body mass index (BMI)	BMI will be calculated by dividing body mass by the square of body height	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)
Changes in maximal oxygen uptake (VO2max)	Changes in maximal oxygen uptake (VO2peak) will be assesed via a submaximal test on a treadmill	Baseline (pre), 12 weeks post-training, 16 weeks (post-detraining)

Collaborators and Investigators

• Sponsor: University of Thessaly
• Investigators: Principal Investigator: Chariklia K. Deli, PhD, University of Thessaly

Publications and helpful links

General Publications

• Zheng Y, Ley SH, Hu FB. Global aetiology and epidemiology of type 2 diabetes mellitus and its complications. Nat Rev Endocrinol. 2018 Feb;14(2):88-98. doi: 10.1038/nrendo.2017.151. Epub 2017 Dec 8.
• Gurung M, Li Z, You H, Rodrigues R, Jump DB, Morgun A, Shulzhenko N. Role of gut microbiota in type 2 diabetes pathophysiology. EBioMedicine. 2020 Jan;51:102590. doi: 10.1016/j.ebiom.2019.11.051. Epub 2020 Jan 3.
• Pasini E, Corsetti G, Assanelli D, Testa C, Romano C, Dioguardi FS, Aquilani R. Effects of chronic exercise on gut microbiota and intestinal barrier in human with type 2 diabetes. Minerva Med. 2019 Feb;110(1):3-11. doi: 10.23736/S0026-4806.18.05589-1.
• Torquati L, Gajanand T, Cox ER, Willis CRG, Zaugg J, Keating SE, Coombes JS. Effects of exercise intensity on gut microbiome composition and function in people with type 2 diabetes. Eur J Sport Sci. 2023 Apr;23(4):530-541. doi: 10.1080/17461391.2022.2035436. Epub 2022 Mar 23.

Helpful Links

• IDF Diabetes Atlas - 10th Edition

Study record dates

Study Major Dates

• Study Start (Actual): March 10, 2025
• Primary Completion (Estimated): May 30, 2026
• Study Completion (Estimated): May 30, 2026

Study Registration Dates

• First Submitted: August 10, 2024
• First Submitted That Met QC Criteria: August 17, 2024
• First Posted (Actual): August 20, 2024

Study Record Updates

• Last Update Posted (Actual): March 28, 2025
• Last Update Submitted That Met QC Criteria: March 24, 2025
• Last Verified: March 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Endocrine System Diseases; Metabolic Diseases; Glucose Metabolism Disorders; Diabetes Mellitus, Type 2; Diabetes Mellitus
• Other Study ID Numbers: Ex-GM-T2D study

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No