Influence of the Diversity and Composition of the Microbiota in the Development of Pediatric Fatty Liver (MicroKid)

Influence of the Diversity and Composition of the Microbiota in the Development of Pediatric Fatty Liver

Influence of the Diversity and Composition of the Microbiota in the Development of Pediatric Fatty Liver: Identification of Biomarkers and Development of Personalized Therapy: The MicroKid Project

The objectives of the present study are: 1) to identify the intestinal and salivary microbiota associated with the presence and severity of hepatic steatosis in children (Study I: case-control study), and 2) to develop a personalized 12-week intervention program based on diet and exercise to examine its effects on the diversity and composition of the microbiota in children with hepatic steatosis (Study II: intervention study)

The MicroKid project will acts first as a case-control study (Study I) in order to identify the hepatic steatosis and intestinal and salivary microbiota in children grouped as non-overweight, obese-non-hepatic steatosis, and obese-hepatic steatosis. Then, an intervention study (Study II) will be developed for those children with obesity (i.e., obese-non-hepatic steatosis, and obese-hepatic steatosis groups). Methodology: A total of 60 children, 8-12 years-old, will be assigned to control (non-overweight children, N= 20), obese-non-hepatic steatosis (children with obesity, but without hepatic steatosis, N=20), and obese-hepatic steatosis (children with obesity and hepatic steatosis, N= 20) groups (Study I: case-control study). The obesity and obesity + hepatic steatosis groups will attend to a 12-weeks healthy lifestyle education program (2 days/month) and home-based exercise program (minimum 3 days/week) (Study II: intervention study). The combined intervention program for the Study II will include: i) healthy lifestyle education program focused on dietary and lifestyle guidelines for both children and parents (2 days/month, 60 min), and ii) exercise program based on high-intensity interval training which combines aerobic and resistance training (at least 3 days/week, from 38 to 44 min). Measurements: In the Study I (i.e., case-control study), all participants will be evaluated at baseline. For the Study II (i.e., intervention study), only those participants that belongs to obese-non-hepatic steatosis and obese-hepatic steatosis groups, will be additionally evaluated after the intervention program (12-week). The following outcomes will be measured: hepatic fat fraction and abdominal adiposity (magnetic resonance imaging), intestinal and salivary microbiota, body composition (bioimpedance), cardiometabolic risk factors, liver enzymes, physical fitness (field-fitness tests), physical activity (accelerometry), sleep (accelerometry), dietary habits (24h recalls, and food frequency questionnaires), and pubertal development and sociodemographic characteristics will be measured.

Healthy lifestyle education program focused on dietary and lifestyle guidelines for both children and parents (2 days/month, 60 min), and exercise program based on high-intensity interval training which combine aerobic and resistance training (at least 3 days/week, from 38 to 44 min).

Healthy lifestyle education program focused on dietary and lifestyle guidelines for both children and parents (2 days/month, 60 min), and exercise program based on high-intensity interval training which combine aerobic and resistance training (at least 3 days/week, from 38 to 44 min).

The intervention program includes an educational program promoting healthy dietary habits and physical activity (nutritionist and exercise physiologist) (2 times/month, for children and parents), and supervised home-based exercise (from 3 to 5 times/week, 38-44 min) program for 12-weeks.

Hepatic fat fraction measured by magnetic resonance imaging before and after 12-weeks intervention program

Visceral adipose tissue measured by magnetic resonance imaging before and after 12-weeks intervention program

Subcutaneous abdominal adipose tissue measured by magnetic resonance imaging before and after 12-weeks intervention program

Intermuscular abdominal adipose tissue measured by magnetic resonance imaging before and after 12-weeks intervention program

Systolic and diastolic blood pressure measured by sphygmomanometer before and after 12-weeks intervention program

Cardiorespiratory fitness, upper- and lower-limbs, and speed agility measured by the Alpha-fitness battery.

Dietary habits history assessed by food frequency questionnaires before and after 12-weeks intervention program

Inclusion Criteria: Obesity defined based on the sex-and-age specific body mass index standards 8-12 years old Exclusion Criteria: Medical conditions that hamper their participation in the exercise program