Synergistic Protection of Combined Probiotic Conditioned Media against Neonatal Necrotizing Enterocolitis-Like Intestinal Injury

Abstract

Balance among the complex interactions of the gut microbial community is important for intestinal health. Probiotic bacteria can improve bacterial balance and have been used to treat gastrointestinal diseases. Neonatal necrotizing enterocolitis (NEC) is a life-threatening inflammatory bowel disorder primarily affecting premature infants. NEC is associated with extensive inflammatory NF-κB signaling activation as well as intestinal barrier disruption. Clinical studies have shown that probiotic administration may protect against NEC, however there are safety concerns associated with the ingestion of large bacterial loads in preterm infants. Bacteria-free conditioned media (CM) from certain probiotic organisms have been shown to retain bioactivity including anti-inflammatory and cytoprotective properties without the risks of live organisms. We hypothesized that the CM from Lactobacillus acidophilus (La), Bifidobacterium infantis (Bi), and Lactobacillus plantarum (Lp), used separately or together would protect against NEC. A rodent model with intestinal injury similar to NEC was used to study the effect of CM from Lp, La/Bi, and La/Bi/Lp on the pathophysiology of NEC. All the CM suppressed NF-κB activation via preserved IκBα expression and this protected IκBα was associated with decreased liver activity of the proteasome, which is the degrading machinery for IκBα. These CM effects also caused decreases in intestinal production of the pro-inflammatory cytokine TNF-α, a downstream target of the NF-κB pathway. Combined La/Bi and La/Bi/Lp CM in addition protected intestinal barrier function by maintaining tight junction protein ZO-1 levels and localization at the tight junction. Double combined La/Bi CM significantly reduced intestinal injury incidence from 43% to 28% and triple combined La/Bi/Lp CM further reduced intestinal injury incidence to 20%. Thus, this study demonstrates different protective mechanisms and synergistic bioactivity of the CM from different organisms in ameliorating NEC-like intestinal injury in an animal model.

Bifidobacterium adolescentis protects against necrotizing enterocolitis and upregulates TOLLIP and SIGIRR in premature neonatal rats

“…These effects might be mediated by products secreted by probiotic bacteria. Probiotic conditioned media contain secreted products, free of intact bacteria, and it was recently reported that this media reduces NEC-like intestinal damage in an animal model [35]. Probiotic conditioned media inhibites the NF-κB signaling pathway and its proinflammatory cytokine production [36], which contributes to attenuating the intestinal inflammatory response [36].…”

Current Research on the Epidemiology, Pathogenesis, and Management of Necrotizing Enterocolitis

“…An extensive discussion is beyond the scope of this review and unfortunately we seem no closer to a definitive answer despite large-scale trials, such as ProPrems [82] and PIPS [83]. Hopefully, mechanistic studies [84,85,86,87] together with a more detailed understanding of the microbiome and its influence on the development of NEC (referred to above) will help us find a way out of this impasse.…”

The role of intestinal epithelial barrier function in the development of NEC

“…31 The potential mechanisms by which probiotics may prevent NEC have been extensively studied in experimental animal models. 86,[104][105][106][107][108][109][110][111][112][113][114][115][116] Specifically, their effect on TJs has been studied by a number of laboratories. In 2009, Khailova, at al., published that oral administration of Bifidobacterium bifidum (Bb) decreased elevated protein levels of ileal occludin and claudin-3 observed in neonatal rats with NEC.…”

“…69 A separate group showed Bifidobacterium infantis (Bi) preserved the intestinal barrier during experimental NEC in mice by allowing occludin and claudin-4 to localize appropriately at the TJ. 80 In a particularly elegant study, Shiou, et al, 106 , found neonatal rats with NEC given conditioned media from combinations of Lactobacillus plantarum, Lactobacillus acidophilus and Bifidobacterium infantis cultures were protected from intestinal barrier dysfunction and maintained ZO-1 at the TJ. A small clinical trial also confirmed that probiotics can also improve intestinal barrier function by reducing intestinal permeability in premature infants 64 and this may be a mechanism by which probiotics can reduce NEC in premature infants.…”