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Probiotic Lactobacillus Species Strengthen Intestinal Barrier Function and Tight Junction Integrity in Experimental
Brian P Blackwood1,2, Carrie Y Yuan2, Douglas R Wood2
1Ann and Robert H. Lurie Children's Hospital of Chicago, Department of Pediatric Surgery, Chicago, Illinois, USA.
Insights
Probiotics like Lactobacillus rhamnosus and Lactobacillus plantarum strengthened intestinal barrier function in vitro. In vivo, they were protective against necrotizing enterocolitis (NEC) only when combined with Cronobacter sakazakii.
Area of Science:
- Gastroenterology
- Microbiology
- Neonatology
Background:
- Necrotizing enterocolitis (NEC) is a severe intestinal disease in newborns, affecting 5% of NICU admissions.
- Probiotics show variable efficacy in NEC prevention, with their impact on intestinal barrier function needing further investigation.
- Tight junctions (TJ) are crucial for maintaining intestinal epithelial integrity.
Purpose of the Study:
- To investigate the effects of Lactobacillus rhamnosus and Lactobacillus plantarum on intestinal barrier function and TJ integrity in experimental NEC models.
- To evaluate the protective potential of these probiotics against NEC in vitro and in vivo.
Main Methods:
- Utilized an in vitro model with Caco-2 cells treated with probiotics and challenged with EGTA or LPS.
- Assessed trans-epithelial resistance (TER) and fluorescein isothiocyanate dextran flux to measure barrier function.
- Employed an in vivo rat model of NEC infected with Cronobacter sakazakii (CS) to evaluate probiotic effects on intestinal injury and ZO-1 expression.
Main Results:
- In vitro, probiotics significantly increased TER and reduced permeability in Caco-2 cells, preserving TJ structure.
- In vivo, probiotics alone exacerbated intestinal injury in rat pups.
- Probiotics demonstrated a protective effect against NEC when administered concurrently with CS, normalizing intestinal injury and permeability.
Conclusions:
- Lactobacillus species enhance intestinal barrier function and TJ integrity in an in vitro NEC model.
- Probiotics are not beneficial alone but offer protection against NEC in vivo when co-administered with Cronobacter sakazakii.
Abstract:
Necrotizing enterocolitis (NEC) is a serious intestinal disease that occurs in newborn infants. It is associated with major morbidity and affects 5% of all infants admitted to neonatal intensive care units. Probiotics have variable efficacy in preventing necrotizing enterocolitis. Tight junctions (TJ) are protein complexes that maintain epithelial barrier integrity. We hypothesized that the probiotics Lactobacillus rhamnosus and Lactobacillus plantarum strengthen intestinal barrier function, promote TJ integrity, and protect against experimental NEC. Both an in vitro and an in vivo experimental model of NEC were studied. Cultured human intestinal Caco-2 cells were pretreated with L. rhamnosus and L. plantarum probiotics. TJ were then disrupted by EGTA calcium switch or LPS to mimic NEC in vitro. Trans-epithelial resistance (TER) and flux of fluorescein isothiocynate dextran was measured. TJ structure was evaluated by ZO-1 immunofluorescence. In vivo effects of ingested probiotics on intestinal injury and ZO-1 expression were assessed in a rat model of NEC infected with Cronobacter sakazakii (CS). Caco-2 cells treated with individual probiotics demonstrated higher TER and lower permeability compared to untreated cells (p<0.0001). ZO-1 immunofluorescence confirmed TJ stability in treated cells. Rat pups fed probiotics alone had more intestinal injury compared with controls (p=0.0106). Probiotics were protective against injury when given in combination with CS, with no difference in intestinal injury compared to controls (p=0.21). Increased permeability was observed in the probiotic and CS groups (p=0.03, p=0.05), but not in the probiotic plus CS group (p=0.79). Lactobacillus sp. strengthened intestinal barrier function and preserved TJ integrity in an in vitro experimental model of NEC. In vivo, probiotic bacteria were not beneficial when given alone, but were protective in the presence of CS in a rat model of NEC.
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