The Association of Weight With Surgical Morbidity in Infants Undergoing Enterostomy Reversal: A Study of the NSQIP-Pediatrics Database.

INTRODUCTION: Optimal criteria and timing for enterostomy closure (EC) in neonates is largely based on clinical progression and adequate weight, with most institutions using 2.0-2.5 kg as the minimum acceptable weight. It is unclear how the current weight cutoff affects post-operative morbidity. AIM: To determine how infant weight at the time of EC influences 30-day complications. METHODS: Infants weighing ≤4000 g who underwent EC were identified in the 2012-2019 ACS NSQIP-P database. Demographics, comorbidities, and 30-day outcomes were assessed using univariate analysis. Multivariable logistic regression controlling for ASA score, nutritional support, and ventilator support was used to estimate the independent association of weight on risk of 30-day complications. RESULTS: A total of 1692 neonates from the NSQIP-P database during the years 2012-2019 met inclusion criteria. Neonates weighing <2.5 kg were significantly more likely to have a younger gestational age, require ventilator support, and have concurrent comorbidities. Major morbidity, a composite outcome of the individual postoperative complications, was observed in 283 (16.7%) infants. ASA classifications 4 and 5, dependence on nutritional support, and ventilator support were independently associated with increased risk of 30-day complications. With respect to weight, we found no significant difference in major morbidity between infants weighing <2.5 kg and infants weighing ≥2.5 kg. CONCLUSION: Despite using a robust, national dataset, we could find no evidence that a defined weight cut-off was associated with a reduction in major morbidity, indicating that weight should not be a priority factor when determining eligibility for neonatal EC. LEVEL OF EVIDENCE: III.

Bile salts increase epithelial cell proliferation through HuR-induced c-Myc expression.

BACKGROUND: Bile salts increase intestinal mucosal proliferation through an increase in c-Myc, a transcription factor that controls the expression of numerous translation regulatory proteins. HuR is an RNA-binding protein that regulates translation of target mRNAs. RNA-binding proteins can control mRNA stability by binding to AU- and U-rich elements located in the 3'-untranslated regions (3'-UTRs) of target mRNAs. AIM: To determine how bile salt-induced c-Myc stimulates enterocyte proliferation. METHODS: Enterocyte proliferation was measured both in vivo using C57Bl6 mice and in vitro using IEC-6 cells after taurodeoxycholate (TDCA) supplementation. HuR and c-Myc protein expression was determined by immunoblot. c-Myc mRNA expression was determined by PCR. HuR expression was inhibited using specific small interfering RNA. HuR binding to c-Myc mRNA was determined by immunoprecipitation. RESULTS: TDCA increased enterocyte proliferation in vivo and in vitro. TDCA stimulates translocation of HuR from the nucleus to the cytoplasm. Cytoplasmic HuR regulates c-Myc translation by HuR binding to the 3'-UTR of c-Myc mRNA. Increased TDCA-induced c-Myc increases enterocyte proliferation. CONCLUSIONS: Bile salts have beneficial effects on the intestinal epithelial mucosa, which are important in maintaining intestinal mucosal integrity and function. These data further support an important beneficial role of bile salts in regulation of mucosal growth and repair. Decreased enterocyte exposure to luminal bile salts, as occurs during critical illness, liver failure, starvation, and intestinal injury, may have a detrimental effect on mucosal integrity.

Deoxycholic acid causes DNA damage while inducing apoptotic resistance through NF-κB activation in benign Barrett's epithelial cells.

Gastroesophageal reflux is associated with adenocarcinoma in Barrett's esophagus, but the incidence of this tumor is rising, despite widespread use of acid-suppressing medications. This suggests that refluxed material other than acid might contribute to carcinogenesis. We looked for potentially carcinogenetic effects of two bile acids, deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA), on Barrett's epithelial cells in vitro and in vivo. We exposed Barrett's (BAR-T) cells to DCA or UDCA and studied the generation of reactive oxygen/nitrogen species (ROS/RNS); expression of phosphorylated H2AX (a marker of DNA damage), phosphorylated IkBα, and phosphorylated p65 (activated NF-κB pathway proteins); and apoptosis. During endoscopy in patients, we took biopsy specimens of Barrett's mucosa before and after esophageal perfusion with DCA or UDCA and assessed DNA damage and NF-κB activation. Exposure to DCA, but not UDCA, resulted in ROS/RNS production, DNA damage, and NF-κB activation but did not increase the rate of apoptosis in BAR-T cells. Pretreatment with N-acetyl-l-cysteine (a ROS scavenger) prevented DNA damage after DCA exposure, and DCA did induce apoptosis in cells treated with NF-κB inhibitors (BAY 11-7085 or AdIκB superrepressor). DNA damage and NF-κB activation were detected in biopsy specimens of Barrett's mucosa taken after esophageal perfusion with DCA, but not UDCA. These data show that, in Barrett's epithelial cells, DCA induces ROS/RNS production, which causes genotoxic injury, and simultaneously induces activation of the NF-κB pathway, which enables cells with DNA damage to resist apoptosis. We have demonstrated molecular mechanisms whereby bile reflux might contribute to carcinogenesis in Barrett's esophagus.

Acid and bile salt-induced CDX2 expression differs in esophageal squamous cells from patients with and without Barrett's esophagus.

BACKGROUND & AIMS: It is not clear why only a minority of patients with gastroesophageal reflux disease (GERD) develop Barrett's esophagus. We hypothesized that differences among individuals in molecular pathways activated when esophageal squamous epithelium is exposed to reflux underlie the development of Barrett's metaplasia. METHODS: We used esophageal squamous cell lines from patients who had GERD with Barrett's esophagus (normal esophageal squamous [NES]-B3T and NES-B10T) and without Barrett's esophagus (NES-G2T and NES-G4T) to study effects of acid and bile salts on expression of the CDX2 gene. Bay 11-705, Ad5 inhibitor kappaB(IkappaB)alpha-SR, and site-directed mutagenesis were used to explore effects of nuclear factor-kappaB (NF-kappaB) inhibition on CDX2 promoter activity; DNA binding of the NF-kappaB subunits p50 and p65 was assessed by chromatin immune-precipitation. RESULTS: Acid and bile salts increased CDX2 messenger RNA (mRNA), protein, and promoter activity in NES-B3T and NES-B10T cells, but not in NES-G2T or NES-G4T cells. Inhibition of NF-kappaB abolished the increase in CDX2 promoter activity. Increased CDX2 promoter activity was associated with nuclear translocation of p50, which bound to the promoter. We found CDX2 mRNA in 7 of 10 esophageal squamous biopsy specimens from patients with Barrett's esophagus, but in only 1 of 10 such specimens from patients who had GERD without Barrett's esophagus. CONCLUSIONS: Acid and bile salts induce CDX2 mRNA and protein expression in esophageal squamous cells from patients with Barrett's esophagus, but not from GERD patients without Barrett's esophagus. We speculate that these differences in acid- and bile salt-induced activation of molecular pathways may underlie the development of Barrett's metaplasia.

Sphingosine-1-phosphate regulates the expression of adherens junction protein E-cadherin and enhances intestinal epithelial cell barrier function.

BACKGROUND: The regulation of intestinal barrier permeability is important in the maintenance of normal intestinal physiology. Sphingosine-1-phosphate (S1P) has been shown to play a pivotal role in enhancing barrier function in several non-intestinal tissues. The current study determined whether S1P regulated function of the intestinal epithelial barrier by altering expression of E-cadherin, an important protein in adherens junctions. METHODS: Studies were performed upon cultured differentiated IECs (IEC-Cdx2L1 line) using standard techniques. RESULTS: S1P treatment significantly increased levels of E-cadherin protein and mRNA in intestinal epithelial cells (IECs) and also led to E-cadherin localizing strongly to the cell-cell border. S1P also improved the barrier function as indicated by a decrease in 14C-mannitol paracellular permeability and an increase in transepithelial electrical resistance (TEER) in vitro. CONCLUSIONS: These results indicate that S1P increases levels of E-cadherin, both in cellular amounts and at the cell-cell junctions, and leads to improved barrier integrity in cultured intestinal epithelial cells.

Cutaneous ciliated cyst: a case report with focus on mullerian heterotopia and comparison with eccrine sweat glands.

Cutaneous ciliated cyst is an exceedingly rare, benign lesion most commonly found in the dermis or subcutis of the lower extremities of young female patients in their second and third decades. The pathogenesis of the cyst is unknown. We report a cutaneous ciliated cyst in the lower extremity of a 13-year-old female patient. On histologic examination, clusters of eccrine sweat glands were observed adjacent to the cyst. Upon comparison of the immunohistochemical profile of the cutaneous ciliated cyst and the eccrine sweat glands, they appeared almost completely unrelated. The histologic, immunohistochemical, and ultrastructural findings of this case and the literature provide evidence in favor of the Mullerian heterotopia theory.

Sphingosine-1-phosphate protects intestinal epithelial cells from apoptosis through the Akt signaling pathway.

OBJECTIVE: The regulation of apoptosis of intestinal mucosal cells is important in maintenance of normal intestinal physiology. SUMMARY: Sphingosine-1-phosphate (S1P) has been shown to play a critical role in cellular protection to otherwise lethal stimuli in several nonintestinal tissues. METHODS: The current study determines whether S1P protected normal intestinal epithelial cells (IECs) from apoptosis and whether Akt activation was the central pathway for this effect. RESULTS: S1P demonstrated significantly reduced levels of apoptosis induced by tumor necrosis factor-alpha (TNF-alpha)/cycloheximide (CHX). S1P induced increased levels of phosphorylated Akt and increased Akt activity, but did not affect total amounts of Akt. This activation of Akt was associated with decreased levels of both caspase-3 protein levels and of caspase-3 activity. Inactivation of Akt by treatment with the PI3K chemical inhibitor LY294002 or by overexpression of the dominant negative mutant of Akt (DNMAkt) prevented the protective effect of S1P on apoptosis. Additionally, silencing of the S1P-1 receptor by specific siRNA demonstrated a lesser decrease in apoptosis to S1P exposure. CONCLUSION: These results indicate that S1P protects intestinal epithelial cells from apoptosis via an Akt-dependent pathway.

Taurodeoxycholate increases intestinal epithelial cell proliferation through c-myc expression.

BACKGROUND: Bile salts have been shown to modulate gastrointestinal epithelial restitution, differentiation, and other functions. Prior studies have shown that the bile salt taurodeoxycholate increases cell migration after injury. The purpose of this experiment was to determine the effect that taurodeoxycholate has on intestinal epithelial cell growth, c-myc expression and function. METHODS: IEC-6 or Caco-2 cells were treated with varying concentrations of taurodeoxycholate (.05 to 1 mmol/L) and proliferation determined. Apoptosis was measured by use of DNA fragmentation assay and nuclear staining. Cell phase was determined with propidium iodide flow cytometry. C-myc expression was determined by Northern and Western blot analysis, and c-myc function was inhibited by specific c-myc antisense. RESULTS: There was no change in cell structure. Apoptosis was not induced. Six days after exposure to taurodeoxycholate, IEC-6 cell proliferation was significantly increased. Flow cytometry showed a significant increase in S-phase concentration and a significant decrease in G1-phase concentration of the cell cycle. Taurodeoxycholate also increased c-myc protein and mRNA expression, and inhibition of c-myc function prevented taurodeoxycholate-induced cell proliferation. CONCLUSIONS: Exposure to physiological concentrations of the bile salt taurodeoxycholate increases intestinal epithelial cell proliferation. This effect is at least partially mediated through a c-myc-dependent mechanism. Bile salts can have a beneficial effect on the intestinal mucosa.

Bile salts regulate intestinal epithelial cell migration by nuclear factor-kappa B-induced expression of transforming growth factor-beta.

BACKGROUND: Mucosal restitution is an important repair modality in the gastrointestinal tract. We have shown that taurodeoxycholate increases intestinal epithelial cell migration by increasing TGF-beta expression, and that the transcription factor NF-kappa B regulates TDCA induced cell migration after injury. The objectives of this study were to determine if this is a property shared by other bile salts or an effect specific to TDCA, and to determine if NF-kappa B regulates TGF-beta expression. STUDY DESIGN: Studies were conducted in IEC-6 cells. Cell migration was examined using an in vitro model. TGF-beta protein and mRNA expression was determined by ELISA and Northern blot analysis. Sequence-specific NF-kappa B binding activity was measured by gel shift assays. RESULTS: Taurocholate and deoxycholate at physiologic concentrations significantly increased intestinal epithelial cell migration 6 hours after wounding (p < 0.01), and was associated with a significant increase in specific NF-kappa B binding activity. Inhibition of NF-kappa B activity significantly inhibited cell migration during restitution and resulted in a significant decrease in TGF-beta mRNA expression and protein expression. CONCLUSIONS: We conclude that bile salts at physiologic conditions increase cell migration after injury, an effect regulated by NF-kappa B. Further, NF-kappa B elicits TGF-beta gene transcription during cell migration. These data support a physiologic role of bile salts in the maintenance of intestinal mucosal integrity.

Bile salt supplementation acts via the farnesoid X receptor to alleviate lipopolysaccharide-induced intestinal injury.

BACKGROUND: Intestinal barrier integrity may be disrupted in many conditions allowing for bacterial invasion and ensuing systemic illness. We investigated the efficacy and mechanism of bile salts in protecting the intestinal mucosa integrity after injury through stimulation of cell proliferation and an increased resistance to apoptosis. METHODS: Over 7 days, wild-type C57Bl/6J and Nr1h4(tm1Gonz)/J (farnesoid X receptor [FXR] knockout) male mice received either liquid rodent chow alone (for control animals) or with added 50 mg/kg per day of taurodeoxycholic acid (TDCA; for experimental animals). On day 6, all mice received 10 mL/kg of lipopolysaccharide intraperitoneally. On day 7, small intestines were harvested. After immunohistochemistry with hematoxylin and eosin, activated caspase-3, and 5-bromo2'-deoxy-uridine (BrdU), mean proliferating and apoptotic cells were determined with light microscopy. In vitro, FXR proteins were immunoblotted from cultured cells after exposure to TDCA. FXR expression was then inhibited in the presence and absence of TDCA. Intestinal epithelial proliferation along with c-Myc and FXR protein expressions were determined. RESULTS: C57Bl/6J mice exhibited significant mucosal enterocyte proliferation and decreased mucosal enterocyte apoptosis when provided with supplemental TDCA in their diet. Inhibition of FXR, both in vivo and in vitro, prevented the bile salt-induced enterocyte proliferation and resistance to apoptosis. TDCA exposure stimulated nuclear translocation of FXR resulting in increased expression of c-Myc. CONCLUSION: A diet supplemented with bile salts, especially in patients who have decreased luminal bile salt, may prove beneficial and therapeutic in critical illness where intestinal injury is part of the spectrum.

Dietary bile acid supplementation improves intestinal integrity and survival in a murine model.

PURPOSE: In vitro supplementation of the bile salt, taurodeoxycholic acid (TDCA), has been shown to stimulate proliferation and prevent intestinal apoptosis in IEC-6 cells. We hypothesize that addition of TDCA to a rodent liquid diet will be protective against induced intestinal injury. METHODS: C57Bl6 mice were fed a liquid diet with or without 50-mg/(kg d) TDCA supplementation. After 6 days, the mice were injected with lipopolysaccharide (LPS) (10 mg/kg) to induce intestinal injury. Specimens were obtained 24 hours later and evaluated for intestinal apoptosis, crypt proliferation, and villus length. A separate cohort of animals was injected with LPS (25 mg/kg) and followed 7 days for survival. RESULTS: Mice whose diet was supplemented with TDCA had significantly increased survival. After LPS-induced injury, mice supplemented with TDCA showed decreased intestinal apoptosis by both H&E and caspase-3. They also had increased intestinal proliferation by 5-bromo-2'deoxyuridine staining and increased villus length. CONCLUSIONS: Dietary TDCA supplementation alleviates mucosal damage and improves survival after LPS-induced intestinal injury. Taurodeoxycholic acid is protective of the intestinal mucosa by increasing resistance to injury-induced apoptosis, stimulating enterocyte proliferation, and increasing villus length. Taurodeoxycholic acid supplementation also results in an increased survival benefit. Therefore, bile acid supplementation may potentially protect the intestine from injury or infection.

Intraabdominal pulmonary sequestration presenting with elevated urinary normetanephrine levels.

Carrying a prenatal diagnosis of a left-sided intraabdominal mass, a term female newborn underwent postnatal imaging that confirmed a left suprarenal mass. Urinary normetanephrine levels were elevated. Given a preoperative diagnosis of neuroblastoma, the baby underwent an uneventful resection of the mass en bloc with the left adrenal gland. The pathologic examination returned pulmonary sequestration and a normal adrenal gland. Postoperative urinary catecholamines were normal. To the best of our knowledge, this is the first description of a newborn with an intraabdominal pulmonary sequestration presenting with elevated urinary catecholamines.

Bile salts induce resistance to apoptosis through NF-kappaB-mediated XIAP expression.

Apoptosis plays a critical role in intestinal mucosal homeostasis. We previously showed that the bile salt taurodeoxycholate has a beneficial effect on the intestinal mucosa through an increase in resistance to apoptosis mediated by nuclear factor (NF)-kappaB. The current study further characterizes the effect of bile salts on intestinal epithelial cell susceptibility to apoptosis and determines if the X-linked inhibitor of apoptosis protein (XIAP) regulates bile salt-induced resistance to apoptosis. Exposure of normal intestinal epithelial cells (IEC-6) to the conjugated bile salts taurodeoxycholate (TDCA) and taurochenodeoxycholate (TCDCA) resulted in an increase in resistance to tumor necrosis factor (TNF)-alpha and cycloheximide (CHX)-induced apoptosis, and NF-kappaB activation. Treatment with TDCA and TCDCA resulted in an increase in XIAP expression. Specific inhibition of NF-kappaB by infection with an adenoviral vector that expresses the IkappaBalpha super-repressor (IkappaBSR) prevented the induction of XIAP expression and the bile salt-mediated resistance to apoptosis. Treatment with the specific XIAP inhibitor Smac also overcame this increase in enterocyte resistance to apoptosis. Bile salts inhibited formation of the active caspase-3 from its precursor procaspase-3. Smac prevented the inhibitory effect of bile salts on caspase-3 activation. These results indicate that bile salts increase intestinal epithelial cell resistance to apoptosis through NF-kappaB-mediated XIAP expression. Bile salt-induced XIAP mediates resistance to TNF-alpha/CHX-induced apoptosis, at least partially, through inhibition of caspase-3 activity. These data support an important beneficial role of bile salts in regulation of mucosal integrity. Decreased enterocyte exposure to luminal bile salts, as occurs during starvation and parenteral nutrition, may have a detrimental effect on mucosal integrity.

Substance P regulates migration in rat intestinal epithelial cells.

OBJECTIVE: The current study examined the effect of substance P (SP) upon intestinal epithelial cells and the mechanistic details of this interaction. SUMMARY BACKGROUND DATA: Intestinal epithelial cells must be capable of migration to reseal mucosal wounds for several vital intestinal functions. This process is incompletely understood; however, recent evidence implicates the neurotransmitter SP in this process. METHODS: Normal rat intestinal epithelial cells (IEC-6 cells) were studied to identify the presence of the SP receptor (NK-1 subtype) and then exposed to physiologic doses of SP and antagonists to assess for increased migration. RESULTS: Examination IEC-6 cells revealed the presence of the SP receptor. Wounding of these cells followed by subsequent exposure to SP (10 mol/L) resulted in increased migration. Similarly, SP-induced increases in intracellular calcium concentration and actomyosin stress fiber formation. These effects were all blocked through specific NK-1 receptor antagonists. CONCLUSIONS: These results indicate that SP stimulates intestinal epithelial migration and increases in calcium concentration. These data support a beneficial role for SP in the maintenance of intestinal mucosal homeostasis.

The use of Alloderm in the closure of a giant omphalocele.

Giant omphaloceles are associated with a considerable loss of abdominal domain. Early primary repair of the fascia is either not possible or poorly tolerated by the infant. Current surgical options result in a ventral hernia requiring future surgery or involve the chronic use of prosthetic patches with or without tissue expanders. This case presentation describes an alternative surgical approach that results in early fascial closure using an interposition graft of Alloderm.

Surgical necrotizing enterocolitis and intraventricular hemorrhage in premature infants below 1000 g.

BACKGROUND/PURPOSE: Infants with very low birth weight are at increased risk for both intraventricular hemorrhage (IVH) and necrotizing enterocolitis (NEC). IVH often progresses in severity after initial diagnosis and causes severe neurological morbidity and mortality. The authors examined the role of NEC in the progression of IVH in these infants. METHODS: The authors conducted a retrospective case-control study using data from the University of Maryland neonatal intensive care unit database between 1991 and 2003. From a cohort of 957 infants with very low birth weight, 53 pairs of infants labeled as IVH progression versus controls were selected and closely matched in respect to their gestational age and birth weight. Charts from these infants were reviewed to identify risk factors contributing to IVH progression. RESULTS: Infants with IVH progression were significantly more likely to suffer from NEC (odds ratio, 3.6), whereas infants with surgical NEC showed a greater association with IVH progression (odds ratio, 5.33). Association with thrombocytopenia was also seen (odds ratio, 3.33). Sepsis showed trend toward significance (odds ratio, 1.9; P = .095) for progression of IVH. CONCLUSION: Surgical NEC showed the greatest risk for IVH progression. NEC and thrombocytopenia also appear to be risk factors for IVH progression.

Induced focal adhesion kinase expression suppresses apoptosis by activating NF-kappaB signaling in intestinal epithelial cells.

Focal adhesion kinase (FAK) integrates various extracellular and intracellular signals and is implicated in a variety of biological functions, but its exact role and downstream targeting signals in the regulation of apoptosis in intestinal epithelial cells (IECs) remains unclear. The current study tested the hypothesis that FAK has an antiapoptotic role in the IEC-6 cell line by altering NF-kappaB signaling. Induced FAK expression by stable transfection with the wild-type (WT)-FAK gene increased FAK phosphorylation, which was associated with an increase in NF-kappaB activity. These stable WT-FAK-transfected IECs also exhibited increased resistance to apoptosis when they were exposed to TNF-alpha plus cycloheximide (TNF-alpha/CHX). Specific inhibition of NF-kappaB by the recombinant adenoviral vector containing the IkappaBalpha superrepressor prevented increased resistance to apoptosis in WT-FAK-transfected cells. In contrast, inactivation of FAK by ectopic expression of dominant-negative mutant of FAK (DNM-FAK) inhibited NF-kappaB activity and increased the sensitivity to TNF-alpha/CHX-induced apoptosis. Furthermore, induced expression of endogenous FAK by depletion of cellular polyamines increased NF-kappaB activity and resulted in increased resistance to TNF-alpha/CHX-induced apoptosis, both of which were prevented by overexpression of DNM-FAK. These results indicate that increased expression of FAK suppresses TNF-alpha/CHX-induced apoptosis, at least partially, through the activation of NF-kappaB signaling in IECs.

Gangrenous intestine in a hernia can be reduced.

A 3-month-old former 31-week premature triplet presented with a perforated terminal ileum 36 hours after complete reduction of an incarcerated inguinal hernia. Classic pediatric surgery teaching asserts that gangrenous bowel in an inguinal hernia will not reduce. In this case, gangrenous bowel was reduced and proceeded to perforate after reduction. Though extremely rare, it is possible to reduce gangrenous bowel, and disposition requires reliable observation at home or hospitalization, if circumstances warrant.

Taurodeoxycholate stimulates intestinal cell proliferation and protects against apoptotic cell death through activation of NF-kappaB.

We hypothesized that the NF-kappaB pathway would be operative in the proliferative effect of bile salts on enterocytes. To determine this, we studied the effect of the bile salt taurodeoxycholate on cultured rat enterocyte proliferation and apoptosis and examined the role of NF-kappaB activation in these growth regulatory processes. Intestinal epithelial cells were grown for 6 days with or without taurodeoxycholate. Proliferation was measured. The cells were exposed to a known apoptotic stimulus, TNF-alpha and cyclohexamide. Apoptosis was quantified using cell number and the TUNEL stain. NF-kappaB activation was determined by an electrophoretic mobility shift assay. NF-kappaB activation was inhibited by an IkappaB superrepressor. Taurodeoxycholate stimulated cell proliferation (P < 0.01) and induced resistance to TNF-alpha induced apoptosis (P < 0.01). Taurodeoxycholate induced NF-kappaB activation. Inhibition of NF-kappaB prevented taurodeoxycholate-induced IEC-6 cell proliferation and rendered cells sensitive to TNF-alpha-induced apoptosis. Taurodeoxycholate stimulates intestinal epithelial cell proliferation and protects intestinal epithelial cells from TNF-alpha-induced apoptosis through NF-kappaB. These data support an important beneficial role of bile salts in regulation of mucosal growth and repair. Decreased enterocyte exposure to luminal bile salts, as occurs during starvation and parenteral nutrition, may have a detrimental effect on mucosal integrity.

NF-kappaB regulates intestinal epithelial cell and bile salt-induced migration after injury.

OBJECTIVE: To determine if NF-kappa B regulates intestinal epithelial cell migration and if it has a role during bile salt-induced migration. SUMMARY BACKGROUND DATA: Mucosal restitution is an important repair modality in the gastrointestinal tract. The authors have shown that taurodeoxycholate (TDCA) increases intestinal epithelial cell migration. NF-kappa B regulates activation of a number of genes involved in inflammatory responses. METHODS: Studies were conducted in IEC-6 cells. I kappa B protein expression was determined by Western blot analysis. Sequence-specific NF-kappa B binding activity was measured by EMSA shift assays and nuclear localization by immunohistochemistry. Cell migration was examined by using an in vitro model that mimics the early cell division-independent stages of epithelial restitution. RESULTS: The process of cell migration over the wounded area was associated with a significant increase in NF-kappa B binding activity in IEC-6 cells. Immunohistochemistry revealed translocation of NF-kappa B into the nucleus. Western blot analysis showed that injury decreased I kappa B protein expression. Inhibition of the binding activity by treatment with a specific NF-kappa B inhibitor, MG-132, inhibited cell migration during restitution. Further, exposure to TDCA at the physiologic concentration that induces intestinal epithelial cell migration increased NF-kappa B binding activity, induced NF-kappa B translocation into the nucleus, and decreased I kappa B protein expression. MG-132 also inhibits bile salt-induced cell migration. CONCLUSIONS: NF-kappa B regulates intestinal epithelial cell migration. Bile salts at physiologic concentrations increase cell migration by activation of NF-kappa B. These data show that bile salts may have a role in the maintenance of intestinal mucosal integrity.