Contributing Factors in the Pathobiology of Airway Remodeling in Obesity

Study Overview
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Brief Summary
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There are two aims for this study. The purpose of this study is to determine the effects of body weight and hormones on airway fibrosis (scarring) and lung function in obese & lean asthma subjects compared to obese & lean non-asthma subjects (Aim 1). And in obese subjects with asthma undergoing bariatric surgery compared to obese non-asthma subjects undergoing bariatric surgery (Aim 2).

Detailed Description
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Main Study Specific Aim 1: Determine the effects of signaling on airway fibrosis and lung function in obese asthma and non-asthma patients. The investigators will: •Perform assessments to determine if obese, early-onset asthma patients are more susceptible to airway fibrosis and remodeling than lean, early-onset asthma patients and obese and lean, non-asthma patients.◦ Specific Aim 2: Investigate the mechanism by which bariatric surgery slows the progression of airway fibrosis in obese human asthma. The investigators will: •Perform assessments to determine if airway fibrosis in obese, early-onset asthma and obese non-asthma patients improves following bariatric surgery and weight loss◦

Official Title
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Contributing Factors in the Pathobiology of Airway Remodeling in Obesity

Conditions
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Asthma, Obesity, Obesity, Morbid, Bariatric Surgery Candidate

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Obese asthmatic & lean asthmatic Outpatient adults of either sex 18-60 years of age with an initial asthma diagnosis at < 12 years of age, as defined by the NHLBI National Asthma Education and Prevention Program (NAEPP) guidelines. Lean subjects with body mass index (BMI) ≥ 20 kg/m2 and < 30 kg/m2 or obese subjects with BMI ≥ 30 and ≤ 55 kg/m2 Physician diagnosis of asthma Forced expiratory volume at one second (FEV1) within acceptable limits (>45% predicted before and >55% predicted after, bronchodilator administration). Negative pregnancy test in women of childbearing potential (confirmed during screening). Relatively healthy subjects able to undergo bronchoscopy without complications. Willing and able to give informed consent and adhere to visit/protocol schedules. Read and write in English. Obese non-asthmatic & Lean non-asthmatic Outpatient adults of either sex 18-60 years of age. Lean subjects with body mass index (BMI) ≥ 20 kg/m2 and < 30 kg/m2 or obese subjects with BMI ≥ 30 and ≤ 55 kg/m2 Negative pregnancy test in women of childbearing potential (confirmed during screening). Normal lung function. No clinical history of atopy. No significant medical or psychological issues. Healthy subjects able to undergo bronchoscopy without complications. Willing and able to give informed consent and adhere to visit/protocol schedules. Read and write in English. Asthmatic undergoing bariatric surgery Outpatient adults of either sex 18-60 years of age with an initial asthma diagnosis at < 12 years of age, as defined by the NHLBI NAEPP guidelines. Physician diagnosis of asthma FEV1 within acceptable limits (>45% predicted before and >55% predicted after, bronchodilator administration). Morbidly obese subjects undergoing bariatric surgery and receiving care at the Duke Metabolic and Weight Loss Surgery Center. Negative pregnancy test in women of childbearing potential (confirmed during screening). Relatively healthy subjects able to undergo bronchoscopy without complications. Willing and able to give informed consent and adhere to visit/protocol schedules. Read and write in English. Non-Asthmatic undergoing bariatric surgery Outpatient adults of either sex 18-60 years of age. Morbidly obese subjects undergoing bariatric surgery and receiving care at the Duke Metabolic and Weight Loss Surgery Center. Negative pregnancy test in women of childbearing potential (confirmed during screening). Normal lung function. No clinical history of atopy. No significant medical or psychological issues. Healthy subjects able to undergo bronchoscopy without complications. Willing and able to give informed consent and adhere to visit/protocol schedules. Read and write in English. Exclusion Criteria: Children < 18 years of age. Adults ≥ 18 years of age with an initial asthma diagnosis at ≥ 12 years of age, as defined by the NHLBI NAEPP guidelines. Inpatient status. FEV1 is less than 45% predicted before, or less than 55% predicted after, bronchodilator administration. Upper or lower respiratory tract infection within one month of the study. Use of inhaled or systemic corticosteroids within four weeks of study. Use of long-acting beta-2, GLP-1 receptor agonists, or dipeptidyl peptidase-4 (DPP-4) inhibitors within two weeks of study. Smoking history > 5 pack years or any cigarette use within the previous six months. Significant non-asthma pulmonary disease (stable obstructive sleep apnea is not excluded). Positive pregnancy test for women and/or nursing women. An emergency department visit or inpatient admission for a primary respiratory diagnosis or treatment with antibiotics within 60 days of enrollment. Poorly controlled concomitant conditions that pose additional procedure risk as determined by the investigator. All patients on anticoagulants Uncontrolled sleep apnea Use of e-cigarettes or vape devices of any kind

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Obese asthmatic & lean asthmatic<br>men and women with asthma and either obese or lean BMI | |
| Obese non-asthmatic & lean non-asthmatic<br>men and women without asthma and either obese or lean BMI | |
| Asthmatic undergoing bariatric surgery<br>Obese asthmatic men and women undergoing bariatric surgery | |
| Non-asthmatic undergoing bariatric surgery<br>Obese men and women undergoing bariatric surgery | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Airway fibrosis | Obese asthmatics compared to lean asthmatics, obese non-asthmatics and lean non-asthmatics: A univariate linear model will be constructed to measure the effect of leptin or GLP-1 (glucagon-like peptide-1) on airway fibrosis, as measured by the ratio of Masson's trichrome-stained area to non-stained area in the sub-mucosal region of airway biopsy tissue. | Visit 2 (14 days) | 
| Change in airway fibrosis | Asthmatics undergoing bariatric surgery and non-asthmatics undergoing bariatric surgery: Each patient will serve as its own control in comparing pre- and post-operative airway fibrosis. A univariate linear model will be constructed to measure the effect of bariatric surgery on airway fibrosis, as measured by the ratio of Masson's trichrome-stained area to non-stained area in the sub-mucosal region of airway biopsy tissue. | Visit 2 (14 days), Visit 4 (1 year + 14 days) |