Intestinal Healing Research Articles

Bone morphogenetic protein guts it out

![Figure][1] The red bracket marks the central, acid-producing region of a fruit fly’s midgut. Bone morphogenetic protein (BMP) signaling reins in stem cell division during intestinal healing, [Guo et al.][2] show. If cells in a fruit fly’s midgut suffer damage—say, from noxious

Adipose-derived stem cells enhance tissue regeneration of gastrotomy closure

BackgroundThe aim of this study was to examine whether transplantation of adipose-derived stem cells (ADSCs) improves healing of a gastrotomy closure in rats. In digestive surgery, anastomotic leakage is a serious postoperative complication and anastomotic stenosis may reduce quality of life. Recent studies have suggested that ADSCs play material roles in intestinal healing, acceleration of angiogenesis, and reduction of fibrosis, and treatment with ADSCs may improve healing. Materials and methodsADSCs were isolated from intra-abdominal white adipose tissue of 40 male Wistar rats (weight 300 g) in four groups (n = 10 each). Gastrotomy closures were prepared surgically in all rats. Controls were treated with phosphate-buffered saline injection and sacrificed 7 d (group 1) or 28 d (group 3) after the surgery. Other animals were treated with locally autotransplanted ADSCs (labeled by CM-DiI) and sacrificed 7 d (group 2) or 28 d (group 4) after the surgery. Histopathologic features were evaluated in the four groups. ResultsInjection of ADSCs significantly enhanced angiogenesis and collagen deposition after 7 d, indicating improved healing of the gastrotomy closure. In contrast, ADSC transplantation significantly reduced collagen deposition after 28 d. The bursting pressure was higher in the transplant groups after 7 d. ConclusionsADSCs enhance tissue regeneration in gastrotomy closures by accelerating angiogenesis and fibrosis in the early healing period. In the late period, ADSCs prevent excessive fibrosis and assist in regeneration of tissues that closely resemble the native structure. These results suggest that therapy with transplanted ADSCs might improve postoperative complications in digestive surgery.

Intestine mucosal IL‐22 is reduced following oral probiotic administration: implications on epithelial barrier repair

Interleukin‐22 (IL‐22) is known to play a key regulatory role at mucosal surfaces including the gut. IL‐22 receptor is predominantly expressed on intestinal epithelial cells (IEC) and evidence suggests that IL‐22 can promote intestinal inflammation and mucosal healing. This study demonstrates a role of probiotics in reducing mucosal IL‐22 and investigates the functional role of IL‐22 on IEC in vitro.Rectal biopsies were obtained from active ulcerative colitis patients immediately prior to probiotic (VSL#3) oral administration and approx. 2 months post‐exposure. Biopsies were cultured in complete medium overnight, supernatant collected and spontaneous IL‐22 secretion measured using ELISA. Effects of varying IL‐22 concentration (100ngml−1–1ngml−1) were tested in vitro using both cancer (SW480) and non‐transformed IEC lines. Stimulation was carried out for 48h (proliferation) or 2h (mRNA). A significant reduction in IL‐22 secreted from mucosal biopsies was detected following probiotic treatment (n=9; p<0.03). In our system, addition of IL‐22 to in vitro IEC cultures did not significantly change proliferation rates (n=12, per concentration). IL‐22 induced moderate increases in SOCS3 and TNFα mRNA at the 50ng and 10ng/ml doses.The long‐term effects of IL‐22 on IEC and the predominant source of IL‐22 in the intestinal mucosa will now be investigated.

Program and AbstractsThirty-third Annual Meeting of the Surgical Infection SocietyLas Vegas, NevadaApril 12–15, 2013

Program and AbstractsThirty-third Annual Meeting of the Surgical Infection SocietyLas Vegas, NevadaApril 12–15, 2013

Functional Roles of TGF-β1 in Intestinal Epithelial Cells Through Smad-Dependent and Non-Smad Pathways

Transforming growth factor-β1 (TGF-β1) is one of the growth factors expressed in the gut, and has been shown to play an important role in intestinal mucosal healing. We investigated the effects of TGF-β1 on the cellular functions of intestinal epithelial cells, and also evaluated its signaling pathways in these cells. We used the rat IEC-6 intestinal epithelial cell line for these studies. The expression of TGF-β1/Smad signaling molecules was examined. We evaluated the effect of TGF-β1 on the proliferation and differentiation by the BrdU incorporation assay and real-time PCR. We manipulated the expression levels of Smad2 and Smad3 using an adenovirus system and small interfering RNA to examine the signaling pathways. The expression of Smad2 and Smad3 along the crypt-villus axis was also examined in the murine intestine. IEC-6 cells produced TGF-β1 and expressed functional TGF-β/Smad signaling molecules. The addition of TGF-β1 in the culture medium suppressed the proliferation and increased the expression of a differentiation marker of enterocytes, in a dose-dependent manner. The adenovirus-mediated and small interfering RNA-mediated studies clearly showed that the growth inhibitory effect and the promotion of differentiation were exerted through a Smad3-dependent and a Smad2-dependent pathway, respectively. IEC-6 cells exhibited upregulated expression of an inhibitory Smad (Smad7) as a form of negative feedback via a non-Smad pathway. Smad2 was predominantly expressed in villi, and Smad3 in crypts. TGF-β1 regulates the cellular functions of intestinal epithelial cells through both Smad-dependent and non-Smad pathways.

Skimmed, sterilized, and concentrated bovine late colostrum promotes both prevention and recovery from intestinal tissue damage in mice

Bovine colostrum is a rich source of tissue repair and growth factors, and inhibits gastrointestinal injury induced by the side effects of nonsteroidal antiinflammatory drugs (NSAID), such as indomethacin. Nonsteroidal antiinflammatory drugs are drugs with analgesic and antipyretic effects, but in higher doses they have inflammatory effects. The pathogenesis of small intestinal damage caused by NSAID is unclear. The present study was performed to investigate the antiinflammatory effects of skimmed, sterilized, and concentrated bovine late colostrum on intestinal injury induced by side effects of NSAID, and then to identify the active ingredient in the colostrum for intestinal tissue. In Japan, the sale of bovine colostrum within 5 d after parturition is prohibited by law. Therefore, we focused on bovine late colostrum obtained from healthy lactating cows 6 to 7 d after parturition. Proliferation of small intestine epithelial cells was stimulated in mice fed the colostrum for 1 wk. With regard to indomethacin-induced enteropathy, both prefeeding and postfeeding with colostrum facilitated growth of the intestinal villi, indicating preventive and healing effects. Furthermore, to identify the active ingredient in the colostrum responsible for this effect, the casein and whey fractions were prepared from the colostrum and fed to normal mice. Only the colostrum casein fraction stimulated intestinal villus elongation, whereas the whey fraction and mature milk casein showed no such effect. Taken together, these observations indicate that the skimmed, sterilized, and concentrated bovine late colostrum, especially the casein fraction, could be used to treat the injurious effects of NSAID in the intestine and could be effective for treatment of other ulcerative conditions in the bowel, suggesting that the colostrum has therapeutic potential for intestinal inflammation.

Hypoxia and Integrin-Mediated Epithelial Restitution during Mucosal Inflammation

Epithelial damage and loss of intestinal barrier function are hallmark pathologies of the mucosal inflammation associated with conditions such as inflammatory bowel disease. In order to resolve inflammation and restore intestinal integrity the mucosa must rapidly and effectively repair the epithelial barrier. Epithelial wound healing is a highly complex and co-ordinated process and the factors involved in initiating intestinal epithelial healing are poorly defined. In order for restitution to be successful there must be a balance between epithelial cell migration, proliferation, and differentiation within and adjacent to the inflamed area. Endogenous, compensatory epithelial signaling pathways are activated by the changes in oxygen tensions that accompany inflammation. These signaling pathways induce the activation of key transcription factors, governing anti-apoptotic, and proliferative processes resulting in epithelial cell survival, proliferation, and differentiation at the site of mucosal inflammation. In this review, we will discuss the primary processes involved in epithelial restitution with a focus on the role of hypoxia-inducible factor and epithelial integrins as mediators of epithelial repair following inflammatory injury at the mucosal surface.

Loss of MLK3 signaling impedes ulcer healing by modulating MAPK signaling in mouse intestinal mucosa

Mixed-lineage kinase 3 (MLK3) activates multiple MAPK pathways and can initiate apoptosis, proliferation, migration, or differentiation in different cell types. However, whether MLK3 signaling regulates intestinal epithelial cell sheet migration in vivo is not known. We sought to investigate whether MLK3 signaling is important in intestinal mucosal healing and epithelial cell motility in vivo and in vitro. In vivo, we compared the healing of jejunal mucosal ulcers induced in MLK3 knockout (KO) mice with healing in wild-type (WT) mice. Ulcer healing was 20.8% less at day 3 (P < 0.05) and 18.9% less at day 5 (P < 0.05) in MLK3 KO than WT mice. Within the intestinal mucosa of MLK3 KO mice, ERK and JNK signaling were reduced, phosphatase and tensin homolog deleted on chromosome 10 (PTEN) level was increased, and p38 signaling was unchanged. Parallel in vitro studies using an MLK inhibitor assessed the role of MLK signaling in human Caco-2 intestinal epithelial migration across collagen substrates. The MLK inhibitor reduced closure of circular wounds in Caco-2 monolayers. MLK inhibition reduced ERK and JNK, but not p38, signaling in Caco-2 cells. Although PTEN is increased after MLK inhibition, it does not influence MLK-mediated cell migration. These findings indicate that disruption of MLK3 signaling impairs ulcer healing by suppressing ERK and JNK signaling in vitro and in mouse intestinal mucosa in vivo. These results reveal a novel role for MLK3 signaling in the regulation of intestinal epithelial migration in vivo and suggest that MLK3 may be an important target for the regulation of intestinal mucosal healing.

Searching for the molecular benchmark of intestinal anastomotic healing in rats: an experimental study

Objective: Intestinal anastomotic healing processes differ greatly from analogous more widely-researched cutaneous phenomena. To date, we still lack comprehension of the particularities of the physiology of intestinal healing. Here, we examine the mRNA response time course to formation of an anastomosis.

Involvement of Coagulation and Hemostasis in Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD), Crohn's disease and ulcerative colitis (UC) are idiopathic, intestinal and systemic inflammatory disorders which are immunologically mediated with the activation of plasma proteolytic cascades. The activation of coagulation in IBD is related to the activity and colonic extension of the disease, but may still be persistent in a quiescent stage. Factor XIII seems to be as much a coagulation factor as a connective tissue factor which may contribute to intestinal healing. Fibrinolytic capacity is reduced in systemic circulation of IBD patients. Platelets activation is a feature of IBD which contributes to a pathogenic inflammatory sequel. There is evidence that coagulation activation may in turn mediate and amplify inflammatory cascades in IBD, especially via activating PARs related pathways. The etiology of thromboembolism in IBD seems to be multifactorial but is largely attributable to the coagulation activation and platelet aggregation during systemic inflammation. Thromboembolic (TE) complications in both Crohn's disease and UC appear to have at least 3-4 fold increased risk of developing compared to control patients. Currently, no single TE laboratory marker has a predictive value, but a recently developed endogenous thrombin potential test may have a potentially predicative value in IBD. At present, no interaction between IBD and inherited factors of thrombophilia has been found. An efficacy of heparin treatment in UC is still controversial, although heparin is safe in UC flare. Prophylactic anticoagulation against TE is currently not fully defined, however, high - risk patients should be considered for using a moderate dose of heparin.

Perioperative Pain Relief by a COX-2 Inhibitor Affects Ileal Repair and Provides a Model for Anastomotic Leakage in the Intestine

The authors examined the potential of the cyclooxygenase 2 (COX-2) inhibitor carprofen to reproducibly induce anastomotic leakage. In experiment 1, an anastomosis was constructed in both ileum and colon of 20 rats, and they were given carprofen (5 mg/kg subcutaneously every 24 hours) or buprenorphine (0.02 mg/kg subcutaneously every 12 hours). In another 20 rats an anastomosis was constructed in either ileum or colon, and all received carprofen (experiment 2). Animals were sacrificed after 3 days. In experiment 1, the ileal dehiscence rate was 60% in the carprofen group and 0% in the buprenorphine group (P = .0108). Colonic anastomoses in both groups remained patent. In experiment 2, the anastomotic leakage rate was 80% in ileum and 0% in colon. Thus, COX-2 inhibitors can severely interfere with intestinal healing, particularly in the ileum. Perioperative administration of carprofen yields a unique model for anastomotic leakage, which allows translational research on the effectiveness of perisuture line reinforcement.

Sa1847 Relationship Between Mucosal Healing and Intestinal Healing in Crohn's Disease Management

Sa1847 Relationship Between Mucosal Healing and Intestinal Healing in Crohn's Disease Management

Mo2073 Impact of Blood Biomarker of Neoadjuvant Treated Patients With Esophageal Carcinoma

Introduction: Anastomotic leakage is one of the causes of increased morbidity and mortality in gastrointestinal and colorectal surgery and it is also associated with elevated costs. The aim of this study was to investigate the effect of synthetic hydrogel sealant and a fibrin sealant on incompetent anastomosis in animal experimental model. Materials and methods: After obtaining approval from our Animal Ethics Committee, ten pigs were anesthetized using a standard protocol. A midline laparotomy was performed and the terminal ileum identified. Subsequently the intestine was completely sectioned 30 cm proximal to the ileocecal valve. All hand-sewn end-to-end anastomoses were performed by the same surgeon, using interrupted absorbable (3-0 polyglactine 910) sutures and leaving an orifice of 18French in the suture line (as shown in Fig 1). Animal were randomized to the application of a synthetic sealant (polyethylene glycol, group I) or fibrin sealant (group II) on the defect and the suture line. Animal were postoperatively followed for 7 days and prematurely sacrificed if sepsis developed. Otherwise, they underwent a second surgery for revision and the anastomosis was isolated and removed for subsequent histological examination. Fischer's and Student's t test was used for statistical analysis. P<0.05 was considered significant. Results: Preoperative data was comparable between groups, with no statistical difference. No septic complications developed in any of the study subjects. Only one animal presented a contained wound dehiscence. On the second surgery, macroscopic findings showed no difference between the 2 groups: There was no evidence of diffuse purulent peritonitis or bowel obstruction. One contained anastomotic leak was found in each group (1/5 vs. 1/5, NS). Adhesions between intestinal loops were found 4 animals: 2 in group I and 2 in group II (2/5 vs. 2/5, NS). An inflammatory mass, containing the leak appeared in 1 case (0/5 vs. 1/5, NS). Microscopically, the local inflammatory response, with granulation tissue and local peritonitis was similar in both groups. Continuity of the mucosal layer was observed in 4 of 10 samples, similar in both groups (2/5 vs. 2/5, NS). Epithelial inclusions in the anastomotic line was found in 1 case in group I and in 3 cases in group II (1/5 vs. 3/5, p=0,26). Discussion: We present a preliminary study describing a new model of incompetent anastomosis in a large animal, designed to study the effect of sealants and glues on intestinal healing. Our findings show that this is a viable model and that both synthetic and fibrin sealant may be useful in reinforcing incompetent anastomoses. Further studies are needed to understand the role of these products in the prevention of anastomotic leaks.

Intestinal healing in rats submitted to ethanol ingestion

To study the effect of alcoholism on intestinal healing and postoperative complications in rats One hundred and sixty rats were divided into two groups: control and treated. The control group received water and the treated group 30% ethanol. After 180 days, colotomy with anastomosis were performed. After, the groups were divided into four subgroups: 20 rats for study at the following moments: 4(th), 7(th), 14(th) and 21(st) postoperative. The analyzed parameters were: weight gain, breaking strength, tissue hydroxyproline, postoperative complications and histopathological study Weight gain was greater in the control group (p<0.05). When all the subgroups were clustered, breaking strength was significantly greater in the control (p<0.05). Histopathology and hydroxyproline dosage did not show differences. There were five surgical site infections in the treated group while the control group showed two (p>0.05). Nine fistulas occurred in the treated group whereas the control group two (p<0.05). There were three deaths in the control group and seven in the treated group (p>0.05). Treated group undergo a malnutrition process that is revealed by lower weight gain. Impaired intestinal healing as indicated by smaller breaking strength. There were a larger number of postoperative complications in the treated animals.

Insulin-like growth factor 1

To summarize the recent evidence that insulin-like growth factor 1 (IGF1) mediates growth effects of multiple trophic factors and discuss clinical relevance. Recent reviews and original reports indicate benefits of growth hormone (GH) and long-acting glucagon-like peptide 2 (GLP2) analogs in short bowel syndrome and Crohn's disease. This review highlights the evidence that biomarkers of sustained small intestinal growth or mucosal healing and evaluation of intestinal epithelial stem cell biomarkers may improve clinical measures of intestinal growth or response to trophic hormones. Compelling evidence that IGF1 mediates growth effects of GH and GLP2 on intestine or linear growth in preclinical models of resection or Crohn's disease is presented, along with a concept that these hormones or IGF1 may enhance sustained growth if given early after bowel resection. Evidence that suppressor of cytokine signaling protein induction by GH or GLP2 in normal or inflamed intestine may limit IGF1-induced growth, but protect against risk of dysplasia or fibrosis, is reviewed. Whether IGF1 receptor mediates IGF1 action and potential roles of insulin receptors are addressed. IGF1 has a central role in mediating trophic hormone action in small intestine. Better understanding of benefits and risks of IGF1, receptors that mediate IGF1 action, and factors that limit undesirable growth are needed.

Medical Therapy for Pediatric Inflammatory Bowel Disease

Pediatric inflammatory bowel disease encompasses a spectrum of disease phenotype, severity, and responsiveness to treatment. Intestinal healing rather than merely symptom control is an especially important therapeutic goal in young patients, given the potential for growth impairment as a direct effect of persistent chronic inflammation and the long life ahead, during which other disease complications may occur. Corticosteroids achieve rapid symptom control, but alternate steroid-sparing strategies with greater potential to heal the intestine must be rapidly adopted. Exclusive enteral nutrition is an alternate short-term treatment in pediatric Crohn's disease. The results of multi-center pediatric clinical trials of both infliximab and adalimumab in Crohn's disease and of infliximab in ulcerative colitis (all in children with unsatisfactory responses to other therapies) have now been reported and guide treatment regimens in clinical practice. Optimal patient selection and timing of anti-TNF therapy requires clinical judgment. Attention must be paid to sustaining responsiveness safely.

A Novel Rodent Model Modifying Perioperative Temperature and Humidity during Bowel Surgery and Mimicking Laparoscopic Conditions

Laparoscopic surgery seems to have a general physiological benefit compared to conventional procedures in several clincal studies especially regarding intestinal anastomotic healing. Reliable experimental data concerning the particular mode of beneficial action are lacking. Clinical studies will not be able to identify the variables responsible for this effect. To establish a feasible, standardized experimental model to investigate variables such as humidity and perioperative room temperature, we employed an incubator designed for neonatal care. This allows individual manipulation and observation of above mentioned variables. Our initial results show that creating intestinal anastomoses in the incubator is safe and easy to perform, creating a valuable possibility to influence perioperative conditions for experimental and clinical research.

Focus on Ulcerative Colitis: Stable Gastric Pentadecapeptide BPC 157

Stable gastric pentadecapeptide BPC 157 (GEPPPGKPADDAGLV, M.W. 1419) may be the new drug stable in human gastric juice, effective both in the upper and lower GI tract, and free of side effects. BPC 157, in addition to an antiulcer effect efficient in therapy of inflammatory bowel disease (IBD) (PL 14736) so far only tested in clinical phase II, has a very safe profile, and exhibited a particular wound healing effect. It also has shown to interact with the NO-system, providing endothelium protection and angiogenic effect, even in severely impaired conditions (i.e., it stimulated expression of early growth response 1 gene responsible for cytokine and growth factor generation and early extracellular matrix (collagen) formation (but also its repressor nerve growth factor 1-A binding protein-2)), important to counteract severe complications of advanced and poorly controlled IBD. Hopefully, the lessons from animal studies, particularly advanced intestinal anastomosis healing, reversed short bowel syndrome and fistula healing indicate BPC 157's high significance in further IBD therapy. Also, this supportive evidence (i.e., no toxic effect, limit test negative, LD1 not achieved, no side effect in trials) may counteract the problems commonly exercised in the use of peptidergic agents, particularly those used on a long-term basis.

The influence of the CO2 pneumoperitoneum on a rat model of intestinal anastomosis healing

BackgroundThe CO2 pneumoperitoneum, which is used for laparoscopic surgery, causes local and systemic effects in patients. Concern arises about what the pressurized anoxic environment of the CO2 pneumoperitoneum has on intestinal healing. Earlier experimental work showed a negative correlation between intestinal healing and the applied intra-abdominal pressure. To further elucidate this, we developed a rat model, in which enterotomy healing can be compared after open or laparoscopic surgery. Possible mechanisms of injury, such as impaired neoangiogenesis or injury through hypoxia-induced pathways were studied.MethodsA new experimental mechanically ventilated rat model was developed. An enterotomy was made and closed via laparotomy (group I) or laparoscopy under CO2 pressures of 5 mmHg (group II) or 10 mmHg (group III). Intestinal healing was tested in vivo after 1 week by bursting-pressure analysis. The effect of the operative procedure on neoangiogenesis was tested by counting factor VIII positive vessels in biopsies of the perianastomotic granulation tissue after 1 week. Intestinal anoxia was tested by quantifying HIF-1α protein levels in intestinal biopsies, taken before the enterotomy closure.ResultsThe bursting pressures were significantly lower after laparoscopic surgery at 10 mmHg CO2 pneumoperitoneum (group III) compared with rats that had undergone open surgery (group I) or laparoscopic surgery at 5 mmHg CO2 pneumoperitoneum (group II). There was no significant quantitative difference between the three groups in the neoangiogenesis nor was there a difference in the amount of HIF-1α measured in the intestinal biopsies.ConclusionsWe developed a surgical model that is well fitted to study the effects of pneumoperitoneum on intestinal healing. With this model, we found further evidence of CO2 pressure-dependant hampered intestinal healing. These differences could not be explained by difference in neoangiogenesis nor local upregulation of hypoxic factors.

Mast Cells in Tissue Healing: From Skin to the Gastrointestinal Tract

Mast cells are largely found at interfaces between the environment and the internal milieu. Early knowledge of the mast cell suggested a role predominantly associated with allergy and pathologic response to antigens, but more recent research has shown a myriad of functions is likely. Wound healing is a complex process of lysis and reconstitution controlled by a series of cell signalling proteins. Mast cells have been shown to play a significant role in the early inflammatory stage of wound healing and also influence proliferation and tissue remodelling in skin. Emerging work implicates the mast cell as a modulator of intestinal healing particularly following surgical anastomosis. The study of mast cells and wound healing involves the use of cell studies and animal models through the use of mast cell inhibitors, promoters and mast cell deficient rodent strains. This review addresses wound healing in skin and the gastrointestinal tract and specifically identifies data pertaining to the role of the mast cell in the process of cell breakdown, repair and regeneration.