Short Chain Fatty Acid Metabolism in COPD — SCFA  

Chronic Obstructive Pulmonary Disease Clinical Trial

Official title: Short-chain Fatty Acid Metabolism in Chronic Obstructive Pulmonary Disease

Status Active, not recruiting

Clinical Trial Summary

The short chain fatty acid (SCFA) metabolism has not been studied in subjects suffering from COPD. The purpose of this study is to compare the SCFA metabolism in COPD patients to healthy matched controls. This protocol is an extension of recent studies about protein digestion and absorption abnormalities in COPD patients. The investigators hypothesize that SCFA production might be lower in COPD patients than in healthy subjects.

Clinical Trial Description

Short-chain fatty acids (SCFAs) are straight or branched-chain fatty acids produced by the intestinal microbiota mainly through fermentation of undigested carbohydrates, but also through degradation of dietary and endogenous proteins. With a share of 90 to 95 %, acetate (C2), propionate (C3), and butyrate (C4) are the most common SCFAs in the colon (3). The molar ratios of acetate to propionate to butyrate are on average approximately 60:20:20 throughout the whole colon. Several human studies tried to determine the in situ production of SCFAs by measuring their content in feces (5-8). But fecal SCFA concentrations do not accurately represent the concentrations in more proximal regions of the colon, because colonocytes absorb more than 95 % of SCFAs to use them as an energy source. Further, the measurement of plasma SCFA concentrations is inaccurate because SCFA plasma levels are low due to high metabolism in colonocytes and liver. Thus, stable isotope studies are needed to examine the colonic production and metabolic fate of SCFAs in healthy and diseased subjects.

SCFAs seem to have anti-inflammatory and immune modulating effects. In COPD an enhanced pulmonary inflammatory response causes a combination of small airways disease (e.g., obstructive bronchiolitis) and/or a destruction of lung parenchyma (emphysema). This leads to a progressive and persistent airflow limitation. Smoking and the exposure to polluted air are main risk factors causing COPD. In a mouse model, a diet rich in whey proteins attenuated emphysema through the suppression of respiratory inflammation. This might have been related to a high colonic SCFA concentration due to the diet. Young et al. proposed that in smokers SCFAs might mitigate both the innate-mediated systemic inflammation controlled by the liver and the inflammatory responses in the lung.

Moreover, Nielsen et al. found that gastrointestinal diseases are significantly more prevalent in COPD patients (15 %) than in patients with other diseases (9%). This might have an influence on the SCFA production in the colon. Gastrointestinal problems may also be assessed through the usage of validated questionnaires. ;

Related Conditions & MeSH terms

• Chronic Obstructive Pulmonary Disease
• Lung Diseases
• Lung Diseases, Obstructive
• Pulmonary Disease, Chronic Obstructive

• NCT number: NCT03327181
• Study type: Interventional
• Source: Texas A&M University
• Status: Active, not recruiting
• Phase: N/A
• Start date: April 19, 2017
• Completion date: April 2022