Mechanisms of Alcohol-Induced Megacecum
Location
Medical Education Building, LSUHSC-NO
Presentation Date
10-10-2019 10:00 AM
End Date
10-10-2019 12:00 PM
Description
Alcohol consumption is prevalent in the United States and the health effects are widespread. For example, alcohol can interfere with gastric and intestinal motility. Previous studies demonstrated megacecum in rodents receiving antibiotics and with chronic alcohol intake. Megacecum is associated with reduced neuronal density in the cecum smooth muscle, which could affect motility or be a consequence of dysmotility. The mechanisms of chronic alcoholinduced megacecum are unknown. We hypothesized that alcohol-induced megacecum involves motility dysfunction, leading to increased permeability and bacterial accumulation. To test this hypothesis, Fisher 344 male rats were randomized to Lieber-DeCarli liquid diet (36% of calories from alcohol) for 10 weeks or pair-fed control groups. Cecum tissue sections were fixed and stained with H&E and fluorescent markers for nucleic acids, alpha-smooth muscle actin (aSMA), and smooth muscle cell myosin heavy chain (SMMHC). Bacterial 16S DNA from cecum contents was measured with qPCR. Albumin from cecum contents and plasma was measured using an Albumin-ELISA kit.We found that, compared to control, rats receiving chronic alcohol developed megacecum with reactive epithelial cells with depleted mucous cells. The muscle layer was atrophied with reduced lamina propria but did not show signs of inflammation. The alcohol group demonstrated heterogenous immunoreactivity with markers against SMMHC and aSMA. Chronic alcohol did not cause an increase in 16S DNA expression in the cecum, indicating equivalent numbers of cecum bacteria in both groups. The alcohol group had lower values of plasma and stool albumin compared with controls. Although alcohol-induced megacecum is not associated with elevated amounts of cecum bacteria or increased cecum permeability, our findings suggest that alcohol influences the epithelial and mucus cells, resembling chemical colitis, and alcohol-induced megacecum is associated with abnormal smooth muscle cell morphology. Overall, alcohol-induced megacecum may have implications on alcohol-induced gut dysmotility.
Recommended Citation
Albares, Peter B., "Mechanisms of Alcohol-Induced Megacecum" (2019). Medical Student Research Poster Symposium. 1.
https://digitalscholar.lsuhsc.edu/sommrd/2019/posters/1
Mechanisms of Alcohol-Induced Megacecum
Medical Education Building, LSUHSC-NO
Alcohol consumption is prevalent in the United States and the health effects are widespread. For example, alcohol can interfere with gastric and intestinal motility. Previous studies demonstrated megacecum in rodents receiving antibiotics and with chronic alcohol intake. Megacecum is associated with reduced neuronal density in the cecum smooth muscle, which could affect motility or be a consequence of dysmotility. The mechanisms of chronic alcoholinduced megacecum are unknown. We hypothesized that alcohol-induced megacecum involves motility dysfunction, leading to increased permeability and bacterial accumulation. To test this hypothesis, Fisher 344 male rats were randomized to Lieber-DeCarli liquid diet (36% of calories from alcohol) for 10 weeks or pair-fed control groups. Cecum tissue sections were fixed and stained with H&E and fluorescent markers for nucleic acids, alpha-smooth muscle actin (aSMA), and smooth muscle cell myosin heavy chain (SMMHC). Bacterial 16S DNA from cecum contents was measured with qPCR. Albumin from cecum contents and plasma was measured using an Albumin-ELISA kit.We found that, compared to control, rats receiving chronic alcohol developed megacecum with reactive epithelial cells with depleted mucous cells. The muscle layer was atrophied with reduced lamina propria but did not show signs of inflammation. The alcohol group demonstrated heterogenous immunoreactivity with markers against SMMHC and aSMA. Chronic alcohol did not cause an increase in 16S DNA expression in the cecum, indicating equivalent numbers of cecum bacteria in both groups. The alcohol group had lower values of plasma and stool albumin compared with controls. Although alcohol-induced megacecum is not associated with elevated amounts of cecum bacteria or increased cecum permeability, our findings suggest that alcohol influences the epithelial and mucus cells, resembling chemical colitis, and alcohol-induced megacecum is associated with abnormal smooth muscle cell morphology. Overall, alcohol-induced megacecum may have implications on alcohol-induced gut dysmotility.
Comments
Mentor: Flavia M Souza-Smith, PhD (Department of Physiology)