Congenital Short-Bowel Syndrome: Clinical and Genetic Presentation in China.

BACKGROUND: Congenital short-bowel syndrome (CSBS) is a rare disorder characterized by retardation of intestinal development. However, it is still not well recognized at present. In this study, the etiological, clinical, and genetic characteristics of CSBS in China were analyzed. METHODS: Nine infants with CSBS were recruited. Full-thickness biopsy findings were evaluated by histopathology. Whole-exome sequencing was performed to identify mutations in patients and their family members. All patients were followed up at >1 year of age. RESULTS: Six of 9 infants had malrotation, and 2 patients had intestinal atresia. The average total small-bowel length was 51.7 (40-75) cm. Coxsackie and adenovirus receptor-like membrane protein (CLMP) mutations were found in 5 patients and were related to decreases in ileal goblet cells and mucous secretion. Among these 5 patients, 3 shared the same mutation (c. 206G>A p.R69H), 1 patient had an exon 3-5 deletion, and 1 patient had the C.655T>G, p.Cys219Gly, and C.389-2A>C. Another case carried a loss-of-function mutation in filamin A (FLNA). In the other 3 patients, no pathogenic mutations in genes related to intestinal development were found. The rate of catheter-related bloodstream infection was 4.3 per 1000 catheter days, and intestinal failure-associated liver disease (IFALD) was 77.8%. The median follow-up duration was 24.1 months. Eight patients were weaned off parenteral nutrition (PN). Six patients still exhibited malnutrition during follow-up. CONCLUSIONS: Infants with CSBS often need long-term PN and remain at risk of SBS-related complications. CLMP and FLNA mutations are associated with CSBS in the Chinese population.

Lupus causing small bowel obstruction.

A 20-year-old female patient was admitted to hospital in 2015 with 1 year history of recurrent abdominal pain, distension, borborygmi and nausea. The patient had a background of systemic lupus erythematous (SLE) diagnosed 4 years before, with skin, joint and renal involvement. The initial investigations have shown a long segment of ileal inflammation with upstream obstruction. Differential diagnoses were mainly SLE enteritis or concomitant Crohn's. Patient failed the initial conservative management and had a laparotomy with small bowel (SB) resection and ileostomy. The histology was suggestive of autoimmune enteritis. Although bowel involvement is a frequent feature of SLE, surgery for obstruction is extremely rare. Postoperatively, she had an emergency admission and was diagnosed with SB volvulus with perforation. She underwent further resection and stoma refashioning in 2016. As a consequence, she developed short gut syndrome. Eventually, the stoma was reversed and parenteral nutrition was stopped and weight became stable.

The role of intermediate filaments in maintaining integrity and function of intestinal epithelial cells after massive bowel resection in a rat.

PURPOSE: Intermediate filaments (IFs) are a part of the cytoskeleton that extend throughout the cytoplasm of all cells and function in the maintenance of cell-shape by bearing tension and serving as structural components of the nuclear lamina. In normal intestine, IFs provide a tissue-specific three-dimensional scaffolding with unique context-dependent organizational features. The purpose of this study was to evaluate the role of IFs during intestinal adaptation in a rat model of short bowel syndrome (SBS). MATERIALS AND METHODS: Male rats were divided into two groups: Sham rats underwent bowel transection and SBS rats underwent a 75% bowel resection. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined 2 weeks after operation. Illumina's Digital Gene Expression (DGE) analysis was used to determine the cytoskeleton-related gene expression profiling. IF-related genes and protein expression were determined using real-time PCR, Western blotting and immunohistochemistry. RESULTS: Massive small bowel resection resulted in a significant increase in enterocyte proliferation and concomitant increase in cell apoptosis. From the total number of 20,000 probes, 16 cytoskeleton-related genes were investigated. Between these genes, only myosin and tubulin levels were upregulated in SBS compared to sham animals. Between IF-related genes, desmin, vimentin and lamin levels were down-regulated and keratin and neurofilament remain unchanged. The levels of TGF-ß, vimentin and desmin gene and protein were down-regulated in resected rats (vs sham animals). CONCLUSIONS: Two weeks following massive bowel resection in rats, the accelerated cell turnover was accompanied by a stimulated microfilaments and microtubules, and by inhibited intermediate filaments. Resistance to cell compression rather that maintenance of cell-shape by bearing tension are responsible for contraction, motility and postmitotic cell separation in a late stage of intestinal adaptation.

Concise Review: The Potential Use of Intestinal Stem Cells to Treat Patients with Intestinal Failure.

Intestinal failure is a rare life-threatening condition that results in the inability to maintain normal growth and hydration status by enteral nutrition alone. Although parenteral nutrition and whole organ allogeneic transplantation have improved the survival of these patients, current therapies are associated with a high risk for morbidity and mortality. Development of methods to propagate adult human intestinal stem cells (ISCs) and pluripotent stem cells raises the possibility of using stem cell-based therapy for patients with monogenic and polygenic forms of intestinal failure. Organoids have demonstrated the capacity to proliferate indefinitely and differentiate into the various cellular lineages of the gut. Genome-editing techniques, including the overexpression of the corrected form of the defective gene, or the use of CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 to selectively correct the monogenic disease-causing variant within the stem cell, make autologous ISC transplantation a feasible approach. However, numerous techniques still need to be further optimized, including more robust ex vivo ISC expansion, native ISC ablation, and engraftment protocols. Large-animal models can to be used to develop such techniques and protocols and to establish the safety of autologous ISC transplantation because outcomes in such models can be extrapolated more readily to humans. Stem Cells Translational Medicine 2017;6:666-676.

Genetic screening of Congenital Short Bowel Syndrome patients confirms CLMP as the major gene involved in the recessive form of this disorder.

Congenital short bowel syndrome (CSBS) is an intestinal pediatric disorder, where patients are born with a dramatic shortened small intestine. Pathogenic variants in CLMP were recently identified to cause an autosomal recessive form of the disease. However, due to the rare nature of CSBS, only a small number of patients have been reported to date with variants in this gene. In this report, we describe novel inherited variants in CLMP in three CSBS patients derived from two unrelated families, confirming CLMP as the major gene involved in the development of the recessive form of CSBS.

Tis7 deletion reduces survival and induces intestinal anastomotic inflammation and obstruction in high-fat diet-fed mice with short bowel syndrome.

Effective therapies are limited for patients with parenteral nutrition-dependent short bowel syndrome. We previously showed that intestinal expression of the transcriptional coregulator tetradecanoyl phorbol acetate-induced sequence 7 (tis7) is markedly increased during the adaptive response following massive small bowel resection and tis7 plays a role in normal gut lipid metabolism. Here, we further explore the functional implications of tis7 deletion in intestinal lipid metabolism and the adaptive response following small bowel resection. Intestinal tis7 transgenic (tis7(tg)), tis7(-/-), and wild-type (WT) littermates were subjected to 50% small bowel resection. Mice were fed a control or a high-saturated-fat (42% energy) diet for 21 days. Survival, body weight recovery, lipid absorption, mucosal lipid analysis, and the morphometric adaptive response were analyzed. Quantitative real-time PCR was performed to identify tis7 downstream gene targets. Postresection survival was markedly reduced in high-fat, but not control, diet-fed tis7(-/-) mice. Decreased survival was associated with anastomotic inflammation and intestinal obstruction postresection. High-fat, but not control, diet-fed tis7(-/-) mice had increased intestinal IL-6 expression. Intestinal lipid trafficking was altered in tis7(-/-) compared with WT mice postresection. In contrast, high-fat diet-fed tis7(tg) mice had improved survival postresection compared with WT littermates. High-fat diet feeding in the setting of tis7 deletion resulted in postresection anastomotic inflammation and small bowel obstruction. Tolerance of a calorie-rich, high-fat diet postresection may require tis7 and its target genes. The presence of luminal fat in the setting of tis7 deletion promotes an intestinal inflammatory response postresection.

Insulin-like growth factor 2 and its enterocyte receptor are not required for adaptation in response to massive small bowel resection.

PURPOSE: Enhanced structural features of resection-induced intestinal adaptation have been demonstrated following the administration of multiple different growth factors and peptides. Among these, the insulin-like growth factor (IGF) system has been considered to be significant. In this study, we employ mutant mouse strains to directly test the contribution of IGF2 and its enterocyte receptor (IGF1R) toward the adaptation response to massive small bowel resection (SBR). METHODS: IGF2-knockout (IGF2-KO) (n=8) and intestine specific IGF1R-knockout mice (IGF1R-IKO) (n=9) and their wild type (WT) littermates (n=5, n=7, respectively) underwent 50% proximal SBR. At post-operative day 7, structural adaptation was measured as crypt depth and villus height. Rates of enterocyte proliferation and apoptosis were also recorded. RESULTS: The successful deletion of IGF2 and IGF1R expression in the enterocytes was confirmed by RT-PCR and Western blot, respectively. Normal adaptation occurred in both IGF2-KO and IGF1R-IKO mice after 50% SBR. Post-operative rates of proliferation and apoptosis in both IGF2-KO and IGF1R-IKO mice were no different than their respective controls. CONCLUSION: IGF2 and functional IGF1R signaling in enterocytes are both dispensable for resection-induced adaptation responses. The mechanism for IGF-stimulation of intestinal adaptation may involve other ligands or cellular compartments within the intestine.

CXCL5 is required for angiogenesis, but not structural adaptation after small bowel resection.

PURPOSE: Intestinal adaptation is the compensatory response to massive small bowel resection (SBR) and characterized by lengthening of villi and deepening of crypts, resulting in increased mucosal surface area. Previous studies have demonstrated increased villus capillary blood vessel density after SBR, suggesting a role for angiogenesis in the development of resection-induced adaptation. Since we have previously shown enhanced expression of the proangiogenic chemokine CXCL5 after SBR, the purpose of this study was to determine the effect of disrupted CXCL5 expression on intestinal adaptation. METHODS: CXCL5 knockout (KO) and C57BL/6 wild type (WT) mice were subjected to either a 50% proximal SBR or sham operation. Ileal tissue was harvested on postoperative day 7. To assess for adaptation, villus height and crypt depth were measured. Submucosal capillary density was measured by CD31 immunohistochemistry. RESULTS: Both CXCL5-KO and WT mice demonstrated normal structural features of adaptation. Submucosal capillary density increased in the WT but not in the KO mice following SBR. CONCLUSION: CXCL5 is required for increased intestinal angiogenesis during resection-induced adaptation. Since adaptive villus growth occurs despite impaired CXCL5 expression and enhanced angiogenesis, this suggests that the growth of new blood vessels is not needed for resection-induced mucosal surface area expansion following massive SBR.

The role of enteral fat as a modulator of body composition after small bowel resection.

BACKGROUND: After massive small bowel resection (SBR), a postoperative diet high in fat is associated with enhanced villus growth. The purpose of this study was to further elucidate the quantity and composition of enteral fat in structural and metabolic changes after SBR. METHODS: C57/Bl6 mice underwent a 50% proximal SBR. Mice were then randomized to receive a low-fat diet (12% kcal fat), medium-fat diet (44% kcal fat), or high-fat diet (HFD; 71% kcal fat) ad libitum. In a separate experiment, mice underwent 50% proximal SBR and then were randomized to liquid diets of 42% kcal of fat in which the fat was composed of menhaden oil, milk fat, or olive oil. After 2 weeks, mice underwent body composition analysis and the small intestine was harvested. RESULTS: Mice that ingested the greatest amount of enteral fat (HFD) had the greatest percent lean mass. When the effects of the different kinds of enteral fat were analyzed, mice that consumed menhaden oil had the greatest percent lean mass with the greatest overall retention of preoperative weight. CONCLUSION: These findings suggest that enteral fat enriched in omega-3 fatty acids may offer clinically relevant metabolic advantages for patients with short gut syndrome.

Wnt/ß-catenin signaling cascade down-regulation following massive small bowel resection in a rat.

BACKGROUND: Growing evidence suggests that the Wnt/ß-catenin signaling cascade is implicated in the control of stem cell activity, cell proliferation, lineage commitment, and cell survival during normal development and tissue regeneration of the gastrointestinal epithelium. The roles of this signaling cascade in stimulation of cell proliferation after massive small bowel resection are unknown. The purpose of this study was to evaluate the role of Wnt/ß-catenin signaling during late stages of intestinal adaptation in a rat model of short bowel syndrome (SBS). METHODS: Male rats were divided into two groups: sham rats underwent bowel transection and SBS rats underwent a 75 % bowel resection. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined 2 weeks after operation. Illumina's digital gene expression analysis was used to determine Wnt/ß-catenin signaling gene expression profiling. Twelve Wnt/ß-catenin-related genes and ß-catenin protein expression were determined using real-time PCR, western blotting and immunohistochemistry. RESULTS: From the total number of 20,000 probes, 20 genes related to Wnt/ß-catenin signaling were investigated. From these genes, seven genes were found to be up-regulated and eight genes to be down-regulated in SBS vs. sham animals with a relative change in gene expression level of 20 % or more. From 12 genes determined by real-time PCR, nine genes were down-regulated in SBS rats compared to control animals including target gene c-Myc. SBS rats also showed a significant decrease in ß-catenin protein compared to control animals. CONCLUSION: Two weeks following massive bowel resection in rats, Wnt/ß-catenin signaling pathway is inhibited. In addition, it appears that cell differentiation rather than proliferation is most important in the late stages of intestinal adaptation.

NOD2 mutations are associated with the development of intestinal failure in the absence of Crohn's disease.

BACKGROUND & AIMS: Short bowel syndrome (SBS) and intestinal failure (IF) are multi-factorial conditions which in adults result from extensive intestinal resection. NOD2 is an intracellular pattern recognition receptor associated with CD. An unexpected high frequency of NOD2 mutations has been found in patients undergoing intestinal transplantation (35%). The role of NOD2 in a cohort with SBS/IF not specifically requiring intestinal transplantation has not been studied yet. METHODS: The course of 85 patients with non-malignant SBS/IF was characterized. The major NOD2 mutations, as well as ATG16L1 and IL23R were determined. The allele frequencies were compared to the published frequencies of CD patients and controls. RESULTS: In non-CD patients (72%) allele frequencies of NOD2 mutations were statistically more frequent than in controls (14% vs 6%, p = 0.006). In CD patients (28%) allele frequencies were not different between SBS and controls (29% vs 22%, p = 0.23). NOD2 mutations were neither associated with parameters potentially heralding the need for transplantation nor with an earlier time to the indication for intestinal transplantation. CONCLUSIONS: NOD2 mutations are associated with the development of SBS/IF in the absence of CD, but not with specific complications. NOD2 mutations may increase the risk for more extensive intestinal resection or may impair intestinal adaptation.

Upregulation of proapoptotic microRNA mir-125a after massive small bowel resection in rats.

OBJECTIVE: Short bowel syndrome remains a condition of high morbidity and mortality, and current therapeutic options carry significant side effects. To identify new treatments we focused on postresection changes in microRNAs--short noncoding RNAs, which suppress target genes--and suggest a previously undiscovered role for microRNA-125a (mir-125a) in intestinal adaptation. METHODS: Rats underwent either 80% massive small bowel resection or transection and were harvested after 48 hours. Jejunum was harvested for microRNA microarrays, laser capture microdissection, and RNA and protein analysis. Mir-125a was overexpressed in intestinal epithelium-6 (crypt-derived) cells (IEC-6) and effects on proliferation and apoptosis determined using MTS and flow cytometry. Expression of potential targets of mir-125a in rat jejunum and IEC-6 cells was determined using quantitative real-time polymerase chain reaction (RNA) and Western blotting (protein). RESULTS: Resection upregulated mir-125a and mir-214 by 2.4-folds and 3.2-folds, respectively. Highest levels of expression were noted in the crypt fraction. Mir-125a overexpression induced apoptosis and resultant growth arrest in IEC-6 cells. The expression of the prosurvival Bcl-2 family member Mcl-1 was downregulated in both mir-125a-overexpressing IEC-6 cells and in jejunum of resected rats, confirming Mcl-1 as a previously undiscovered target of mir-125a. CONCLUSIONS: Upregulation of mir-125a suppresses the prosurvival protein Mcl1, producing the increase in apoptosis known to accompany the proliferative changes characteristic of intestinal adaptation. Our data highlight a potential role for microRNAs as mediators of the adaptive process and may facilitate the development of new therapeutic options for short bowel syndrome.

CLMP is required for intestinal development, and loss-of-function mutations cause congenital short-bowel syndrome.

BACKGROUND & AIMS: Short-bowel syndrome usually results from surgical resection of the small intestine for diseases such as intestinal atresias, volvulus, and necrotizing enterocolitis. Patients with congenital short-bowel syndrome (CSBS) are born with a substantial shortening of the small intestine, to a mean length of 50 cm, compared with a normal length at birth of 190-280 cm. They also are born with intestinal malrotation. Because CSBS occurs in many consanguineous families, it is considered to be an autosomal-recessive disorder. We aimed to identify and characterize the genetic factor causing CSBS. METHODS: We performed homozygosity mapping using 610,000 K single-nucleotide polymorphism arrays to analyze the genomes of 5 patients with CSBS. After identifying a gene causing the disease, we determined its expression pattern in human embryos. We also overexpressed forms of the gene product that were and were not associated with CSBS in Chinese Hamster Ovary and T84 cells and generated a zebrafish model of the disease. RESULTS: We identified loss-of-function mutations in Coxsackie- and adenovirus receptor-like membrane protein (CLMP) in CSBS patients. CLMP is a tight-junction-associated protein that is expressed in the intestine of human embryos throughout development. Mutations in CLMP prevented its normal localization to the cell membrane. Knock-down experiments in zebrafish resulted in general developmental defects, including shortening of the intestine and the absence of goblet cells. Because goblet cells are characteristic for the midintestine in zebrafish, which resembles the small intestine in human beings, the zebrafish model mimics CSBS. CONCLUSIONS: Loss-of-function mutations in CLMP cause CSBS in human beings, likely by interfering with tight-junction formation, which disrupts intestinal development. Furthermore, we developed a zebrafish model of CSBS.

Effect of alpha-naphthylisothiocyanate-induced liver injury on intestinal adaptation in a rat model of short bowel syndrome.

BACKGROUND/PURPOSE: Progressive hyperbilirubinemia and end-stage liver failure are among the most serious complications of short bowel syndrome (SBS), representing the principle cause of death in a majority of fatal cases. In the current study, we examined the effects of alpha-naphthylisothiocyanate (ANIT)-induced liver injury on intestinal adaptation in a rat model of SBS. METHODS: Male rats were divided into four groups: Sham rats underwent bowel transection (n = 8), Sham liver-injury rats underwent bowel transection and IP injection of ANIT (100 mg/kg, n = 8), SBS rats underwent a 75% bowel resection, and SBS-ANIT rats underwent bowel resection and liver injury similar to group sham-ANIT (n = 8). Fourteen days after intervention, liver biopsies and intestinal samples were obtained and evaluated for liver damage and measures of intestinal adaptation. Real time PCR and Western blotting were used to determine the level of bax and bcl-2 mRNA and protein, and p-ERK protein levels. Statistical analysis was performed using the one-way ANOVA test, with p < 0.05 considered statistically significant. RESULTS: All ANIT-treated animals exhibited histological evidence of liver damage that was associated with the expansion of atypical ductal proliferation near the periportal areas, intense neutrophil infiltration in the liver, increased mitotic activity, Kupfer cells hyperplasia and fatty liver degeneration. ANIT-induced liver damage in bowel resected animals was associated with a significant decrease in all parameters of intestinal adaptation including bowel and mucosal weight in jejunum (twofold decrease) and ileum (twofold decrease), mucosal DNA in jejunum (fourfold decrease), mucosal protein in jejunum (threefold decrease) and ileum (threefold decrease), villus height in jejunum (38%) and ileum (34%), and crypt depth in jejunum (24%) and ileum (30%) compared to SBS animals. Both Sham-ANIT and SBS-ANIT rats demonstrated decreased enterocyte proliferation rates that were accompanied by decreased p-ERK protein levels. Lower apoptotic rates in jejunum (40%) and ileum (52%) in SBS-ANIT rats (vs. SBS) coincided with decreased bax mRNA and protein levels. CONCLUSIONS: In a rat model of SBS, ANIT-induced liver injury was associated with decreased enterocyte proliferation and inhibited intestinal adaptation.

Oral insulin stimulates intestinal epithelial cell turnover following massive small bowel resection in a rat and a cell culture model.

PURPOSE: We have recently reported that oral insulin (OI) stimulates intestinal adaptation after bowel resection and that OI enhances enterocyte turnover in correlation with insulin receptor expression along the villus-crypt axis. The purpose of the present study was to evaluate the effect of OI on intestinal epithelial cell proliferation and apoptosis in a rat model of short bowel syndrome (SBS) and in a cell culture model. METHODS: Caco-2 cells were incubated with increasing concentrations of insulin. Cell proliferation and apoptosis were determined by FACS cytometry. Cell viability was investigated using the Alamar Blue technique. Male rats were divided into three groups: Sham rats underwent bowel transection, SBS rats underwent a 75% bowel resection, and SBS-OI rats underwent bowel resection and were treated with OI given in drinking water (1 U/ml) from the third postoperative day. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined on day 15. Real time PCR was used to determine the level of bax and bcl-2 mRNA and western blotting was used to determine bax, bcl-2, p-ERK and AKT protein levels. Statistical analysis was performed using the one-way ANOVA test, with P < 0.05 considered statistically significant. RESULTS: Treatment of Caco-2 cells with insulin resulted in a significant increase in cell proliferation (twofold increase after 24 h and 37% increase after 48 h) and cell viability (in a dose-dependent manner), but did not change cell apoptosis. In a rat model of SBS, treatment with OI resulted in a significant increase in all parameters of intestinal adaptation. Elevated cell proliferation rate in insulin treated rats was accompanied by elevated AKT and p-ERK protein levels. Decreased cell apoptosis in SBS-INS rats corresponded with a decreased bax/bcl-2 ratio. CONCLUSIONS: Oral insulin stimulates intestinal epithelial cell turnover after massive small bowel resection in a rat model of SBS and a cell culture model.

Intestinal adaptation following massive ileocecal resection in 20-day-old weanling rats.

OBJECTIVE: Few infant animal models have been used to study infantile short bowel syndrome (SBS). Most SBS models involve removal of the proximal small bowel followed by jejunoileal anastomosis, which has unclear clinical relevance to human infantile SBS that often results from surgical treatment for necrotizing enterocolitis and involves removal of the ileum, ileocecal valve, and part of or the entire colon. Our objective was to develop a more appropriate SBS model in developing rats. MATERIALS AND METHODS: Twenty-day-old weanling rats were divided into 2 surgery groups, ileocecal resection (ICR) and sham groups, and a control group that did not undergo surgery. All were fed a liquid diet ad libitum for 7 days after surgery or for 7 days in the controls, and body weight, food intake, and stool changes were recorded daily. The rats were then euthanized and intestinal lengths and weights were recorded. Samples of intestine from the distal jejunum and proximal colon were collected for histology. Mucosal samples from the middle, distal jejunum, and colon were collected for measurements of mucosal weights, DNA, RNA, and protein levels. Maltase activity was determined in the small intestine. RESULTS: Eighty-five percent of rats survived the ICR with subsequent development of diarrhea, hyperphagia, and poor growth. Adaptive responses to ICR, as compared with sham, were evidenced by increased intestinal and mucosal weights, DNA, RNA, and protein levels, increased maltase activity and villous thickness in distal jejunum, and increased mucosal thickness in the colon. CONCLUSIONS: This ICR model in weanling rats is appropriate for studying human infantile SBS.

Epidermal growth factor receptor-directed enterocyte proliferation does not induce Wnt pathway transcription.

BACKGROUND: Epidermal growth factor receptor (EGFR) stimulation enhances intestinal adaptation after massive small bowel resection (SBR), measured by taller villi, deeper crypts, and augmented enterocyte proliferation. Min mice with constitutively active beta-catenin signaling demonstrate enhanced villus growth after SBR, suggesting a role for the Wnt pathway during adaptation. Because there is crosstalk between EGFR signaling and the Wnt pathway, we hypothesized that beta-catenin is modulated by EGFR-induced enterocyte proliferation. METHODS: Rat intestinal epithelial cells were stimulated with EGF and cytoplasmic to nuclear trafficking of beta-catenin was measured. Beta-catenin-directed transcription was also tested via transfection with a TOP/FOP luciferase reporter. Downstream transcriptional target expression was measured in murine intestine after SBR. RESULTS: Epidermal growth factor-treated rat intestinal epithelial cells exhibited increased proliferation compared to serum-deficient cells in the face of no detectable accumulation of nuclear beta-catenin. The luciferase assay results showed minimal transcription activity in response to EGF. In vivo experiments revealed no significant difference in expression of beta-catenin targeted genes in crypt enterocytes after SBR. CONCLUSIONS: The mechanism for EGFR-induced proliferation of enterocytes does not appear to involve a transcriptional role for beta-catenin. The effects of EGFR signaling on beta-catenin-mediated cell adhesion remain to be investigated.

Kit-negative fibroblast-like cells expressing SK3, a Ca2+-activated K+ channel, in the gut musculature in health and disease.

The apamin-sensitive component of the inhibitory response of the gastrointestinal musculature involves the small conductance Ca(2+)-activated K(+) channel SK3. Kit-immunoreactive (ir) interstitial cells of Cajal appear to be involved in nitrergic inhibition while the role of the recently described CD34-ir fibroblast-like cells adjacent to, but distinct from, the cells of Cajal remains elusive. The distribution of SK3 was studied by immunohistochemistry in the normal human gut, in motility disorders with a lack of cells of Cajal (infantile hypertrophic pyloric stenosis and Hirschsprung's disease) and in mice deficient in cells of Cajal. SK3 immunoreactivity was observed exclusively in Kit-negative interstitial cells adjacent to, but distinct from, the Kit-ir interstitial cells of Cajal in the normal gut. The distribution of SK3-ir cells was not altered in conditions where cells of Cajal were lacking. These cells were CD34-ir fibroblast-like cells in the human gut and in the mouse stomach, while SK3-ir cells in the mouse intestine were CD34 negative. As SK channels are reportedly involved in inhibitory neurotransmission, our morphological observations suggest that SK3-ir interstitial cells, distinct from the Kit-ir interstitial cells of Cajal, may represent a novel cellular component in the control of excitability of the digestive musculature. Further studies will be required to directly address the function of these cells.

Cytokine gene transcription by NF-kappa B family members in patients with inflammatory bowel disease.

We examined the expression of the transcription factor NF-kappa B, a nuclear trans-acting factor known to play a key role in cytokine gene regulation, in patients with inflammatory bowel disease (IBD). It was found that LP macrophages in Crohn's disease (CD) and ulcerative colitis (UC) display high levels of NF-kappa B DNA-binding activity accompanied by an increased production of interleukin (IL)-1, IL-6, and tumor necrosis factor (TNF) alpha. Western blot studies showed an increased expression of the p50 and c-rel subunits of NF-kappa B; however, the most striking finding was an increased expression level of NF-kappa B p65 in patients with CD and UC. Selective downregulation of p65 in IBD macrophages by a specific antisense phosphorothioate oligonucleotide was sufficient to considerably reduce production of proinflammatory cytokines. These results demonstrate a characteristic increase of NF-kappa B binding levels in patients with IBD. The data suggest that antisense DNA targeting NF-kappa B p65 can be used as a novel molecular approach for the treatment of patients with IBD.

Functional intestinal obstruction associated with malrotation and short small-bowel.

Two siblings are presented in whom a recognized syndrome of functional small-bowel obstruction with malrotation and short small-bowel was diagnosed. The previously described association with pyloric stenosis was not present in our cases. They do, however, support the view that this syndrome has an autosomal recessive model of inheritance. A deficiency of argyrophil neurones in the myenteric plexus has been noted in this syndrome but more precise neurohistochemical studies are required to define the exact deficit involved.