Testing the Gravitostat in Humans: the Impact of a Weighted Vest in Patients Post Bariatric Surgery on Fat-free Mass Retention and Weight Loss

The mechanisms regulating fat mass homeostasis are incompletely understood although recent animal and human trials would suggest that there is a leptin independent regulatory pathway which may play a role in weight control and maintenance. Although evidence would suggest that external loading in patients with obesity may promote body weight loss, this has not been explored in patients following bariatric surgery.

The aim of this study is to investigate the mechanisms regulating weight loss and the potential role of the 'gravitostat' in fat free mass retention in patients following bariatric surgery.

Study Overview

• Status: Suspended
• Conditions: Obesity
• Intervention / Treatment: Device: Weighted vest

Detailed Description

The aim of the study is to investigate the mechanisms that regulate weight loss, particularly following bariatric surgery. Previous animal studies have suggested that there is an underlying regulatory process controlled by 'the gravitostat' which is an evolutionary adaptation responsible for weight control and maintenance. Studies exploring this concept in rodent models have suggested that artificially increasing the animal's weight with the implantation of weighted capsules results in greater weight loss in mice with obesity but does not affect those of normal weight. We will use weighted vests in patients following surgery to replicate this increased mechanical loading to determine whether a similar process occurs in humans. This will improve our understanding of the underlying processes regulating weight in patients with obesity and following bariatric surgery.

• Study Type: Interventional
• Enrollment (Anticipated): 40
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Ireland
  • Dublin, Ireland, Dublin 4
    • University College Dublin Clinical Research Centre

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 60 years (ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Undergoing bariatric surgery- Roux en Y gastric bypass or sleeve gastrectomy
• Age 18-60
• BMI >30kg/m2
• Reporting regular physical exercise (>3 days/week)
• Willingness to comply with the study protocol

Exclusion Criteria:

• Sedentary lifestyle
• Chronic pain that is constant and impairs the quality of life such as severe back, hip or knee pain
• Reduced mobility requiring the use of a mobility aid
• Undergoing revisional surgery
• Concerns from the investigator that the participant will be unable to fully comply with the study protocol

Study Plan

How is the study designed?

Design Details

• Primary Purpose: TREATMENT
• Allocation: RANDOMIZED
• Interventional Model: PARALLEL
• Masking: NONE

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: External mechanical loading; Following bariatric surgery (RYGB or SG) patients will be asked to wear a weighted vest for a minimum of 8 hours daily and during physical exercise for three months postoperatively. Weight will be incrementally added on a weekly basis to maintain the baseline weight as patients lose weight following surgery up to a maximum of 15%.	Device: Weighted vest; Patients will wear a weighted vest following bariatric surgery with weight increased incrementally to maintain baseline weight. This vest will be worn for a minimum of 8 hours a day for three months postoperatively.
NO_INTERVENTION: Standard postoperative care; Patients following bariatric surgery (RYGB or SG) will receive standard postoperative care.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Fat free mass retention	Fat free mass retention as measured using DEXA scan	1 year
Weight loss	Weight loss (kg)	1 year

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in protein and inflammatory marker levels myostatin	Change in myostatin	1 year
Changes in protein and inflammatory markers lipocalin-2	Change in lipocalin-2	1 year
Changes in protein and inflammatory markers IGF-1	Change in IGF-1	1 year
Changes in protein and inflammatory markers IL-6	Change in IL-6	1 year
Changes in protein and inflammatory markers	Change in testosterone	1 year

Collaborators and Investigators

• Sponsor: University College Dublin
• Investigators: Principal Investigator: Carel W le Roux, PhD, University College Dublin

Study record dates

Study Major Dates

• Study Start (ACTUAL): April 8, 2021
• Primary Completion (ANTICIPATED): October 3, 2022
• Study Completion (ANTICIPATED): October 3, 2022

Study Registration Dates

• First Submitted: March 18, 2021
• First Submitted That Met QC Criteria: March 19, 2021
• First Posted (ACTUAL): March 22, 2021

Study Record Updates

• Last Update Posted (ACTUAL): October 13, 2022
• Last Update Submitted That Met QC Criteria: October 10, 2022
• Last Verified: October 1, 2022

More Information

Terms related to this study

• Keywords: Obesity; Bariatric surgery; Weight loss maintenance
• Additional Relevant MeSH Terms: Body Weight; Body Weight Changes; Weight Loss
• Other Study ID Numbers: RS20-012

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