Mitochondrial Metabolism and Oxidative Stress in Function of the Physical Exercise and Nutritional Counseling in T2DM

N/AActive Not RecruitingNCT07251504

University of Cadiz146 enrolled

Overview

The goal of this randomized controlled trial is to learn about the effects of different aerobic modalities (moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT)) and diet on mitochondrial properties and oxidative stress in patients with type 2 diabetes (T2D). It will also learn about the different effects of these interventions in men and women. The main questions it aims to answer are: * What is the isolated and combined effect of these exercise modalities and diet? Is there a superior approach for mitochondrial metabolism and oxidative stress in patients with T2D? * Is there a sex-specific best combination choice for these different interventions? * Is there any relation between exercise and diet-induced changes in mitochondrial properties and oxidative stress and other health-related outcomes such as body composition or insulin sensitivity? To answer these questions, researchers designed a two-factor study. One factor was exercise, which had three levels (MICT, HIIT, and the inactive (INACT) condition). The second factor was diet, with two levels (Diet (D) and no diet (ND)). Hence, participants were randomly allocated into 6 groups: INACT-ND, INACT-D, MICT-ND, MICT-D, HIIT-ND, and HIIT-D. Participants did: * Underwent a 12-week intervention within the condition of his/her group * Visit the research group facilities three times per week if in an exercise group or once every two weeks if in a diet group.

This is a randomized controlled trial conducted in the Province of Cádiz (Spain). A total of 146 participants were enrolled in the study and underwent baseline and post-intervention determinations of the study outcomes. Just after the baseline determination, participants were randomly allocated to one of the aforementioned study groups. The randomization process was stratified by sex, which means that approximately 50% of participants in each group were women. All participants received detailed written and verbal information about the study objectives, procedures, benefits, and potential risks before providing written informed consent. This study adhered to the principles of the Declaration of Helsinki and was approved by the Provincial Research Ethics Committee of Cádiz and the Coordinating Committee of Biomedical Research Ethics of Andalucía (registration number 92.21; PEIBA number 1026-N-21; internal codes SICEIA-2025-001870 and SICEIA-2025-000778). At both baseline and post-intervention, participants were scheduled in the morning following an overnight fast of 8-10 hours. They were instructed to maintain their usual lifestyle, abstain from alcohol and caffeine for 24 hours, and avoid strenuous physical activity for 72 hours prior to testing. Procedures included body composition assessment through electrical bioimpedance, a vastus lateralis muscle biopsy, fasting blood collection, and an oral glucose tolerance test (OGTT) by ingesting 75 grams of glucose and blood draws at 30, 60, 90, 120, 150, and 180 minutes post-ingestion. The same protocol was repeated after the 12-week intervention, with exercise groups completing their final training session at least 72 hours before the post-intervention assessments.

Interventions

Nutritional interventionBEHAVIORAL

The nutritional intervention was conducted through biweekly (± 3 days) in-person consultations with a nutritionist or dietitian over an entire period of 12 weeks. Firstly, the patient's diet was analyzed. Then, participants were guided to follow a Mediterranean pattern-based and mildly calorie-restricted diet, with the primary goal of achieving a 5 % reduction in body weight and reducing blood glucose levels. Meal plans were created using Nutrium® software , personalized to each participant's lifestyle and food preferences, and reviewed at each biweekly consultation. The dietary plan included at least 4 meals per day, ensuring a well-distributed intake of carbohydrates, a balanced distribution of macro- and micronutrients, and the inclusion of foods rich in prebiotics and probiotics. Moreover, some suggestions about the combination of foods and culinary techniques were provided. Only one session through the intervention was allowed to be attended telephonically.

The High-Intensity Interval Training (HIIT)OTHER

Participants assigned to the HIIT completed 3 weekly sessions, with 1-2 days of rest between sessions, on a cycle ergometer for 12 weeks. The training load (TL) was determined from an incremental test until volitional exhaustion with one-minute work intervals (from 85% to 165% of maximal power output from a previously performed VO2max test \[Wmax\] and with 10% increments) separated by 1.5-minute rest periods (at 20% Wmax). The program consisted of a 3 minutes warm-up with the first 2 minutes at 20% and last minute at 40% of the TL, followed by 10 series of 1 min duration at 90% of TL, with 1 minute of rest between sets at 40% of TL and ending with 2 minutes of cool-down at 20% of TL (estimated total time of the session: 25 minutes). A 5% increase in workload was applied when, for two consecutive sessions, the first three intervals failed to exceed 85%, and the last five did not reach 90% of maximal HR. Participants were asked to maintain a cadence above 80RPM.

The Moderate-Intensity Continuous Training (MICT)OTHER

Participants assigned to the MICT completed 3 weekly sessions, with 1-2 days of rest between sessions, on a cycle ergometer for 12 weeks. MICT consisted of 50 minutes of continuous pedaling at an intensity approximately 10 % above the lactate threshold, with a cadence between 60-80 rpm. Training load (TL) was increased by 10% if these two conditions were met: 1) no increase of at least 2 beats of heart rate from minute 20 to minute 40 of the training session, and 2) lactate levels below 2 mmol/L in minute 48 of the session. The TL for the first session was determined by an adjustment test consisting of an incremental test with five consecutive 10-minute phases at a constant cadence (60-80 RPM) from 90% to 130% of the ventilatory threshold power, calculated from previously performed FatOx test data, with 10% increments in each step. TL was determined by the phase in which HR increased by ≥ 3 beats between phases and blood lactate levels increased by ≥ 1 mmol/L from the previous phase.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Diagnosis of T2D or prediabetes (glycated hemoglobin ≥ 5.7%) * No history of substance abuse (tobacco, alcohol, or other drugs). * Body mass index \>25 kg/m², maintaining the habitual dietary patterns with stable body weight for at the least 6 months * Stable physical activity and medication regimen for at least 6 months * Not insulin-dependent * Absence of injury, disease, disability, or other known medical condition which could affect the ability to successfully participate in physical exercise tests * Absence of tumours and cancer disease * Absence of other pathologies that could affect the study outcomes. * Not under medication regimen that could affect the study outcomes. * Being able to understand a communication in Spanish or English. * Not pregnant Exclusion Criteria: * Failure to attend more than 2 consecutive or a total of 4 sessions of nutritional intervention. * Failure to attend more than 4 consecutive or a total of 6 sessions of physical training. * Serious injury * Voluntary withdrawal * Increased dose of diabetes medication

Outcomes

Primary Outcomes

Muscle biopsy samples: mitochondrial respiratory capacity

Skin was locally anesthetized, followed by an incision of approximately 6-7mm on the dermal surface. Using sterilized Bergstrom needles, approximately 3-6 mg of skeletal muscle from the lateral vastus were extracted and placed in a BIOPS buffer for immediate analysis of mitochondrial respiration (MR) through high-resolution respirometry. Before, the fibers were mechanically separated in BIOPS buffer using sterilized needles and chemically permeabilized with a 50 μg/ml saponin solution. MR was measured in a specific buffer (Mir05) in duplicate in hyperoxygenated chambers (250-450 mM of oxygen) in an Oxygraph-2k at 37ºC (Oroboros, Innsbruck, Austria). A substrate-uncoupler titration protocol was employed by adding (final concentration): malate (2mM), pyruvate (5mM), glutamate (2mM), MgCl2 (3mM), and ADP (5mM), cytochrome C (10μM), succinate (10mM), and p-trifluoromethoxyphenylhydrazone. Oxygen flux was presented as mass-specific (pmol·s/mg wet weight) and normalized to CS activity.