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The Effect of Bariatric Surgery on Peripheral Nerve Function and Axonal Regeneration (BAR)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT02218866
Recruitment Status : Completed
First Posted : August 18, 2014
Last Update Posted : April 10, 2018
American Diabetes Association
Information provided by (Responsible Party):
Gordon Smith, University of Utah

Brief Summary:
The goal of this research is understand if obesity is a major factor for neuropathy development in patients with and without Type 2 diabetes. This study will examine the relationship between weight, metabolism, and nerve function and regeneration.

Condition or disease
Peripheral Neuropathy Obesity

Detailed Description:

Peripheral neuropathy causes progressive injury to the longest nerves of the body, starting in the toes, then progressing slowly up the leg. Neuropathy often causes pain, numbness, and weakness if the feet and can lead to reduced mobility, foot ulcers, and even amputation. The most common cause is diabetes, but work at the University of Utah finds that prediabetes and other consequences of obesity, including abnormal cholesterol levels, may be associated with neuropathy. Research has shown that these risk factors may damage nerves and interfere with the ability of nerves to grow back after an injury.

This study aims to

  1. characterize peripheral nerve function and cutaneous nerve structure in obese bariatric surgery candidates;
  2. evaluate peripheral nerve regeneration capacity (and other nerve function measures) before and after bariatric surgery in obese subjects with no or mild neuropathy;
  3. examine the relationship between ectopic lipid accumulation, lipotoxic mediators, neuropathy and regeneration capacity in surgical candidates before and one year after surgery.

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Study Type : Observational
Actual Enrollment : 205 participants
Observational Model: Case-Control
Time Perspective: Prospective
Official Title: The Effect of Bariatric Surgery on Peripheral Nerve Function and Axonal Regeneration
Study Start Date : January 2012
Actual Primary Completion Date : December 31, 2017
Actual Study Completion Date : December 31, 2017

Resource links provided by the National Library of Medicine

Group 1
All participants will be examined by a neurologist to test sensation, reflexes, and strength and complete a few questionnaires. Tests will be performed to measure nerve function and small punch skin biopsies will be taken to assess nerve fiber density. Blood and urine tests will measure various markers of interest. Participants will be seen before and after their bariatric surgery.
Group 2

In addition to the procedures described for Group 1, participants in Group 2 will have the following procedures:

  • During bariatric surgery, a small biopsy from the liver and abdominal fat will be taken to examine how fat is processed within the body.
  • At the first visit, after a skin biopsy is taken, a small capsaicin patch will be placed on the lower thigh. The patch will remain in place for 48 hours and will cause the nerves in the immediate area to pull back from the skin. A biopsy will be taken from the patch area 48 hours, 1 month, and 3 months after the initial biopsy. This procedure will be repeated after surgery.
  • MRIs may be performed before and after bariatic surgery.
  • Participants may be asked to complete additional tests to evaluate nerve function
Group 3
Group 3 will comprise of individuals who are not overweight. Participants in this group will undergo a similar evaluation to Group 2.

Primary Outcome Measures :
  1. Change in reinnervation capacity [ Time Frame: 4 - 1 months prior to bariatric surgery, compared to 9 - 12 months after surgery ]

Secondary Outcome Measures :
  1. Change in Utah Early Neuropathy Scale (UENS) [ Time Frame: Baseline to 12 months after bariatric surgery ]
  2. Change in Nerve Conduction Study measures [ Time Frame: Baseline to 12 months after bariatric surgery ]
    Nerve Conduction Study is a procedure routinely used in the diagnosis of neuropathy. Measures will include Sural sensory and Peroneal motor amplitudes and conduction velocities.

  3. Change in nerve fiber density [ Time Frame: Baseline to 12 months after bariatric surgery ]

Biospecimen Retention:   Samples With DNA
DNA, serum, tissue

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   18 Years to 80 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
Participants will be recruited through bariatric surgery clinics in the local area.

Inclusion Criteria:

  • Age 18-80 years old
  • Subjects must fulfill criteria for bariatric surgery.

Exclusion Criteria:

  • History of foot ulceration or neurogenic arthropathy
  • Family history of non-diabetic neuropathy in a first-degree family member.
  • Presence of any disease known to be associated with peripheral neuropathy including but not limited to vitamin deficiency, toxin exposure, paraproteinemia, heavy alcohol use, hepatitis C, HIV.
  • Coumadin use.
  • Inability to understand or cooperate with the procedures of the trial.
  • Known history of sensitivity to capsaicin products.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT02218866

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United States, Utah
University of Utah
Salt Lake City, Utah, United States, 84132
Sponsors and Collaborators
University of Utah
American Diabetes Association
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Principal Investigator: A. Gordon Smith, MD University of Utah
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Responsible Party: Gordon Smith, Professor, University of Utah Identifier: NCT02218866    
Other Study ID Numbers: BAR-UofU
First Posted: August 18, 2014    Key Record Dates
Last Update Posted: April 10, 2018
Last Verified: August 2016
Keywords provided by Gordon Smith, University of Utah:
Bariatric surgery
Additional relevant MeSH terms:
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Peripheral Nervous System Diseases
Neuromuscular Diseases
Nervous System Diseases