Cellular strain amplifies LPS-induced stress signaling in immature enterocytes: potential implications for preterm
Alicia M Alcamo1, Brandon L Schanbacher, Hong Huang
1Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
Insights
Mechanical strain on intestinal cells increases inflammatory responses and reduces growth, potentially contributing to necrotizing enterocolitis (NEC) in infants using nasal continuous positive airway pressure (NCPAP). This suggests abdominal distension may not be benign.
Area of Science:
- Gastroenterology
- Neonatal Research
- Cell Biology
Background:
- Necrotizing enterocolitis (NEC) incidence is rising in infants using nasal continuous positive airway pressure (NCPAP).
- Abdominal distension in NCPAP patients raises concerns about its role in NEC development.
- The study investigates if mechanical strain from distension exacerbates enterocyte inflammation and hinders growth.
Purpose of the Study:
- To test if mechanical strain induces an exaggerated inflammatory response in enterocytes.
- To determine if mechanical strain decreases enterocyte growth and proliferation.
- To assess these effects with and without lipopolysaccharide (LPS) exposure.
Main Methods:
- Utilized a confluent enterocyte (IEC-6) monolayer to assess inflammatory cytokine production and Toll-like receptor 4 (TLR-4) gene expression under 10% mechanical strain.
- Employed low seeding density cultures to measure cell growth and proliferation rates.
- Investigated the combined effects of mechanical strain and LPS.
Main Results:
- Mechanical strain significantly increased interleukin (IL)-8 and IL-6 production at 8 and 24 hours, respectively.
- Toll-like receptor 4 (TLR-4) expression elevated after 48 hours of strain.
- Strain slowed cell proliferation and division; combined strain and LPS showed supra-additive inflammatory effects.
Conclusions:
- Intestinal distension in NCPAP use may increase inflammatory cytokine production.
- This heightened inflammation, especially with abnormal gut bacteria, could be a factor in neonatal intestinal diseases.
- Mechanical strain on enterocytes leads to detrimental inflammatory and growth effects.
Background:
Recent clinical observations of increased necrotizing enterocolitis (NEC) incidence in some nasal continuous positive airway pressure (NCPAP) patients raise concerns about whether the related abdominal distension is benign or contributes to NEC. We tested the hypothesis that mechanical strain causes an exaggerated enterocyte inflammatory response and decreased enterocyte growth and proliferation in the absence and presence of lipopolysaccharide (LPS).
Methods:
First we used a confluent enterocyte (IEC-6) monolayer to investigate effects of strain on inflammatory cytokine production and Toll-like receptor 4 (TLR-4) gene expression. Then we used a low seeding density to measure cell growth and proliferation. Ten percent mechanical strain was applied.
Results:
Significant increases in interleukin (IL)-8 and in IL-6 were observed after 8 and 24 h of cellular strain, respectively, and maintained throughout the study. TLR-4 expression was increased at 48 h. Mechanical strain led to slower proliferation and division whereas LPS alone had minimal effects. The responses of LPS and strain were supra-additive, suggesting synergistic cellular effects.
Conclusion:
We speculate intestinal distension associated with the use of NCPAP, especially in the presence of abnormal gut colonization, may result in increased inflammatory cytokine production and be a contributing factor to neonatal intestinal morbidities.
