Diabetes Reversal and the Subgingival Microbiota

This study seeks to examine the impact of bariatric surgery on oral bacteria in diabetic compared to non-diabetic patients. The purpose of this research study is to examine how diabetes changes the bacteria in the mouth. This is an important question since bacterial changes may impact oral health. Participants will attend a screening and baseline visit prior to bariatric surgery and three post bariatric surgery appointments (3 weeks post, 6 months post and 1 year to 18 months post). Samples collected at each study visit include blood, plaque, and other oral samples. At the last study visit there is an optional dental cleaning.

Study Overview

• Status: Completed
• Conditions: Diabetes type2; Bariatric Surgery Candidate
• Intervention / Treatment: Other: sample collection

• Study Type: Observational
• Enrollment (Actual): 102

Contacts and Locations

Study Locations

• United States
  • Pennsylvania
    • Philadelphia, Pennsylvania, United States, 19104
      • University of Pennsylvania
    • Philadelphia, Pennsylvania, United States, 19104
      • Temple University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 25 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: N/A

• Sampling Method: Non-Probability Sample

Study Population

The study participants will be men and women, 25-65 years old, with a Body Mass Index (BMI) of ≥35 kg/m2 who are scheduled to undergo bariatric surgery at the University of Pennsylvania or Temple University for treatment of obesity or obesity and type 2 diabetes. The total target enrollment is 130 diabetic and 104 normoglycemic subjects.

Description

Inclusion Criteria:

• Men and women undergoing bariatric surgery who are 25-65 years old.
• BMI > 35 kg/m2.
• Diabetic subjects: HbA1c> 6.0% or fasting plasma glucose >126 mg/dl).
• Normoglycemic subjects: HbA1c<5.75% or fasting plasma glucose <100 mg/dl).
• Dental criteria: Minimum of 4 posterior teeth.
• Signed and dated informed consent form.
• Willing to comply with all study procedures and be available for the duration of the study.

Exclusion Criteria:

• Subjects diagnosed with type 1 diabetes, maturity onset diabetes of the young (MODY), or latent autoimmune diabetes in adults (LADA).
• Women who are considering pregnancy or are currently breastfeeding.
• Individuals with a history of chronic inflammatory or autoimmune diseases or taking medications that affect immune function or affect body weight such as chronic systemic steroids.
• Currently smoke more than 10 cigarettes per day.
• Periodontal treatment within 3 months of bacterial sampling.
• Acute periodontal infection (abscess) within 1 month of bacterial sampling or abscess in teeth or adjacent teeth within 1 month of sampling.
• Treatment with antibiotics within one month of sample collection (except as part of the surgical regimen of prophylactic antibiotic immediately prior to surgery).
• A treatment regimen of steroids within 1 month of sample collection.

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Prospective

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Diabetic patients; Diabetic patients who plan to undergo bariatric surgery	Other: sample collection; Blood, plaque, and other oral samples
Normo-glycemic (non-diabetic) patients; Non-diabetic patients who plan to undergo bariatric surgery	Other: sample collection; Blood, plaque, and other oral samples

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Bacterial composition	as determined by 16s rRNA community profiling	18 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Bacterial mRNA profiling	RNA will be isolated then amplified by the MessageAmp II bacterial RNA amplification kit (Ambion/Life Technologies). Ribosomal RNA will be depleted with the RiboZero human/mouse and meta bacterial kits (Epicentre/Illumina) and human mRNA will be depleted with oligo(dT). Illumina sequencing libraries will be constructed with the Illumina TruSeq RNA kit and assessed with an Illumina HiSeq instrument.	18 months
Gingival inflammation	samples will be assessed for inflammatory cytokines (e.g. IL-1β, IL-17 or TNF) by multiplex assay or ELISA assay	18 mos.

Collaborators and Investigators

• Sponsor: University of Pennsylvania
• Collaborators: National Institute of Dental and Craniofacial Research (NIDCR); Ohio State University; Temple University
• Investigators: Principal Investigator: Dana Graves, DDS, DMSc, University of Pennsylvania

Study record dates

Study Major Dates

• Study Start (Actual): March 11, 2019
• Primary Completion (Actual): June 30, 2025
• Study Completion (Actual): June 30, 2025

Study Registration Dates

• First Submitted: August 12, 2022
• First Submitted That Met QC Criteria: August 12, 2022
• First Posted (Actual): August 15, 2022

Study Record Updates

• Last Update Posted (Actual): March 19, 2026
• Last Update Submitted That Met QC Criteria: March 17, 2026
• Last Verified: March 1, 2026

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; Investigative Techniques; Clinical Laboratory Techniques; Diagnostic Techniques and Procedures; Diagnosis; Specimen Handling
• Other Study ID Numbers: 825975; 1R01DE026603-01A1 (U.S. NIH Grant/Contract)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No