Mucosal Epithelial Cell Proliferation Research Articles

Brucea javanica oil alleviates intestinal mucosal injury induced by chemotherapeutic agent 5-fluorouracil in mice.

Background: Brucea javanica (L.) Merr, has a long history to be an anti-dysentery medicine for thousand of years, which is commonly called "Ya-Dan-Zi" in Chinese. The common liquid preparation of its seed, B. javanica oil (BJO) exerts anti-inflammatory action in gastrointestinal diseases and is popularly used as an antitumor adjuvant in Asia. However, there is no report that BJO has the potential to treat 5-Fluorouracil (5-FU)-induced chemotherapeutic intestinal mucosal injury (CIM). Aim of the study: To test the hypothesis that BJO has potential intestinal protection on intestinal mucosal injury caused by 5-FU in mice and to explore the mechanisms. Materials and methods: Kunming mice (half male and female), were randomly divided into six groups: normal group, 5-FU group (5-FU, 60mg/kg), LO group (loperamide, 4.0mg/kg), BJO group (0.125, 0.25, 0.50g/kg). CIM was induced by intraperitoneal injection of 5-FU at a dose of 60mg/kg/day for 5 days (from day 1 to day 5). BJO and LO were given orally 30min prior to 5-FU administration for 7days (from day 1 to day 7). The ameliorative effects of BJO were assessed by body weight, diarrhea assessment, and H&E staining of the intestine. Furthermore, the changes in oxidative stress level, inflammatory level, intestinal epithelial cell apoptosis, and proliferation, as well as the amount of intestinal tight junction proteins were evaluated. Finally, the involvements of the Nrf2/HO-1 pathway were tested by western blot. Results: BJO effectively alleviated 5-FU-induced CIM, as represented by the improvement of body weight, diarrhea syndrome, and histopathological changes in the ileum. BJO not only attenuated oxidative stress by upregulating SOD and downregulating MDA in the serum, but also reduced the intestinal level of COX-2 and inflammatory cytokines, and repressed CXCL1/2 and NLRP3 inflammasome activation. Moreover, BJO ameliorated 5-FU-induced epithelial apoptosis as evidenced by the downregulation of Bax and caspase-3 and the upregulation of Bcl-2, but enhanced mucosal epithelial cell proliferation as implied by the increase of crypt-localized proliferating cell nuclear antigen (PCNA) level. Furthermore, BJO contributed to the mucosal barrier by raising the level of tight junction proteins (ZO-1, occludin, and claudin-1). Mechanistically, these anti-intestinal mucositis pharmacological effects of BJO were relevant for the activation of Nrf2/HO-1 in the intestinal tissues. Conclusion: The present study provides new insights into the protective effects of BJO against CIM and suggests that BJO deserves to be applied as a potential therapeutic agent for the prevention of CIM.

Clinical and Histopathological Characteristics of Colorectal Cancer in Iraq between 2015-2021.

Colorectal cancer (C.R.C.) is the commonest malignancy in the gastrointestinal tract and is the fourth leading reason behind cancer-associated death in the world. It usually begins with the non-cancerous proliferation of mucosal epithelial cells. These growths are polyps and might grow gradually for 10-20 years before becoming cancerous. This study was designed to investigate the epidemiology of the diagnosed cases of colorectal cancer from 2015 to 2021 in Baghdad. A total of 60 cases of different colorectal cancer samples were collected from Medical City Teaching Hospital, Baghdad, and private labs. Clinical information was also collected, including patients' age, tumor size, gender and location, pathological grade, and stage. Results revealed a high incidence of C.R.C. in patients aged 60-90 years for the rate of 40.3%, with a high frequency in the left colon of 59.6%. The dominant tumor size was 5cm in malignant cases, and a high incidence of C.R.C. was seen in the female by 52.0%. While the most frequent tumor stage was stage I.I.A., with a rate of 59.6%, and moderately differentiated was the foremost one with 67.3% (P≤0.05). The most common type of C.R.C. in Iraq is adenocarcinoma, which occurs in patients older than 60years and presented at the I.I.A. stage of disease with moderate tumor grade. Early disease detection and diagnosis are effective in its control and treatment.

Interferon Regulatory Factor 4 (IRF4) Promotes Lipopolysaccharide-Induced Colonic Mucosal Epithelial Cell Proliferation by Regulating Macrophage Polarization

Introduction: Ulcerative colitis (UC) is a chronic disease characterized by diffuse inflammation of the mucosa of colon and rectum. Interferon regulatory factor 4 (IRF4) mediates macrophage anti-inflammatory phenotype (alternatively activated macrophages [M2]). This study aimed to investigate the mechanism of IRF4 in lipopolysaccharide (LPS)-induced colonic mucosal epithelial cell proliferation via the regulation of macrophage polarization. Methods: Human bone marrow-derived macrophages were subjected to interleukin 4 (IL-4) induction. M2 macrophages were identified using flow cytometry and quantitative real-time polymerase chain reaction (qRT-PCR). IRF4 expression in M2 macrophages was detected using Western blot and qRT-PCR. IRF4 expression was silenced in M2 macrophages. IL-10 mRNA expression and protein level were detected using qRT-PCR and Western blot. The binding relation between IRF4 and IL-10 was verified using dual-luciferase and chromatin immunoprecipitation assays. Macrophages under different treatments were cocultured with LPS-induced human colonic mucosal epithelial cells. The levels of inflammatory factors (TNF-α, IL-6, and IL-1β) were detected using enzyme-linked immunosorbent assay. The proliferation of inflammatory cells was measured using Cell Counting Kit-8 assay, and the healing of inflammatory cells was detected using wound healing assay. Results: M2 macrophages alleviated LPS-induced inflammatory responses. IRF4 bound to IL-10 and promoted IL-10 expression. Inhibition of IRF4 reduced IL-10 expression and attenuated the alleviating effect of M2 macrophages on inflammatory responses. Inhibition of IRF4 combined with IL-10 overexpression enhanced the promoting effect of M2 macrophages on inflammatory healing. Conclusion: IRF4 promoted colonic mucosal epithelial cell proliferation by increasing IL-10 expression and regulating macrophage polarization to M2 phenotype, which might be related to UC mucosal healing.

Показатели пролиферации и апоптоза эпителиальных клеток слизистой оболочки желудка у коренных жителей Республики Тыва с Helicobacter pylori-позитивной язвенной болезнью двенадцатиперстной кишки

Показатели пролиферации и апоптоза эпителиальных клеток слизистой оболочки желудка у коренных жителей Республики Тыва с Helicobacter pylori-позитивной язвенной болезнью двенадцатиперстной кишки

The regulatory role of Fos related antigen‑1 in inflammatory bowel disease.

The etiology of inflammatory bowel disease (IBD) remains unclear. The ratio of Fos related antigen‑1 (Fra‑1)‑positive intestinal mucosa epithelial cells is significantly increased in active IBD. This study intends to explore the regulatory role of Fra‑1 in IBD. The Fra‑1 eukaryotic expression vector was constructed and stably transfected to establish the Fra‑1 overexpression HCT‑116 (116‑Fra‑1) intestinal epithelial cell line. The impact of Fra‑1 overexpression on intestinal mucosal epithelial cell damage repair function was tested using a scratch assay. The role of Fra‑1 overexpression on intestinal mucosal epithelial cell proliferation was evaluated using a Cell Counting Kit-8 assay. Apoptosis related proteins, B‑cell lymphoma 2 (Bcl‑2), c‑Myc, Survivin and Bcl‑extra large (Bcl‑xL), expression levels were detected by western blotting. Fra‑1 suppressed intestinal mucosal epithelial cell damage repair and proliferation. Fra‑1 inhibited the protein levels of Bcl‑2, c‑Myc, Survivin, and Bcl‑xL. Fra‑1 overexpression in intestinal mucosal epithelial cells may restrain damage repair after intestinal mucosal injury in IBD remittent period through weakening the protective effect of intestinal mucosa, thus increasing the risk of recurrence. Therefore, suppressing Fra‑1 expression in intestinal mucosal epithelial cells may contribute to IBD remittent maintenance and recurrence delay.

Antiplatelet drug ticagrelor delays gastric ulcer healing in rats.

Adenosine diphosphate P2Y12 receptor antagonist clopidogrel is not sufficiently safe for the gastric mucosa in patients with high risk of peptic ulcer, since it may impair healing of gastric erosions. However, the safety of the novel P2Y12 receptor antagonist ticagrelor in the gastric mucosa has not been elucidated to date. The present study aimed to examine whether ticagrelor delays gastric ulcer healing and to elucidate the involved mechanisms. Gastric kissing ulcers were produced in rats by luminal application of acetic acid solution, and ticagrelor was administered at dose of 10 or 20 mg/kg/day orally for 7 days. On day 8 after ulcer induction, the ulcer size, mucosal epithelial cell proliferation of the ulcer margin, expression levels of epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF), and signal transduction pathways for cell proliferation and angiogenesis were measured and compared between the ticagrelor-treated and untreated model groups. The results revealed that the ulcer size was significantly greater in the ticagrelor-treated group compared with the model group, while the mucosal epithelial cell proliferation of the ulcer margin was significantly decreased in the ticagrelor-treated group. In addition, ticagrelor significantly decreased the ulcer-stimulated expression levels of EGF, VEGF, phosphorylated extracellular signal-regulated kinase (ERK), phosphorylated P38 mitogen-activated protein kinase and nuclear factor-κB P65 at the ulcer margin (P<0.05). These findings suggested that ticagrelor delayed gastric ulcer healing. Furthermore, the possible mechanisms underlying the effect of ticagrelor were associated with its functions of attenuating the expression levels of VEGF and EGF, as well as suppressing the phosphorylation activation of ERK1/2, P38 and nuclear factor-κB P65. Finally, the gastric epithelial cell proliferation and angiogenesis were also inhibited.

Membrane-Permeable Calpain Inhibitors Promote Rat Oral Mucosal Epithelial Cell Proliferation by Inhibiting IL-1α Signaling.

To standardise regenerative medicine using cultured cells, the use of serum-free, chemically defined media will be necessary. We have reported that IL-1α inhibits the growth of epithelial cells in culture and that recombinant IL-1 receptor antagonist (IL-1RA) significantly promotes epithelial cell growth in no feeder layer condition. In this study, we examined inhibitors of calpain, a cysteine proteinase that plays crucial roles in various cellular functions, including IL-1α maturation and secretion. The culturing of epithelial cells in serum-free media supplemented with a membrane-permeable calpain inhibitor significantly promoted growth while suppressing IL-1α maturation and secretion. By contrast, non-membrane-permeable calpain inhibitor treatment did not have these effects. Interestingly, immunoblotting analysis revealed that immature, untruncated, IL-1α expression was also downregulated by cell-permeable calpain inhibitor treatment, and the difference in IL-1α gene expression increased from day 2 to day 6. Although IL-1RA has been reported to promote epithelial cell growth, we detected no synergistic promotion of epithelial cell growth using a calpain inhibitor and IL-1RA. These findings indicate that calpain inhibitors promote epithelial cell proliferation by inhibiting IL-1α maturation at an early phase of epithelial cell culture and by suppressing the positive feedback-mediated amplification of IL-1α signalling.

Abstract LB-251: p27Kip1 suppression of colitis-associated colon cancer mediated through cell intrinsic function in both mucosal epithelia and mucosal T cells

Abstract The cyclin-dependent kinase inhibitor p27Kip1 is a negative regulator of the cell cycle. Reduced expression of p27Kip1 has prognostic significance in several human epithelial cancers. Loss of p27Kip1 expression in cancer cells correlates with tumor aggressiveness, depth of tumor cell invasion and with lack of tumor cell differentiation. However, p27Kip1 also promotes apoptosis and contraction of effector CD4+ T cells, suggesting the potential that suppression of epithelial tumorigenesis may be linked to an intrinsic function of p27Kip1 in T cells. Here we show both mRNA and protein expression of p27Kip1 are significantly decreased in a murine model wherein a T cell-restricted deletion of the gene encoding the TGF-β intermediate, Smad4 (Smad4TKO), results in spontaneous colitis that invariably progresses to colon cancer by the age of 8 months. This phenotype is associated with a consistent decline in the mucosal expression of p27Kip1. To further investigate the role of p27Kip1 in the maintenance of intestinal mucosal homeostasis, we generated a ‘double knockout’ (Smad4TKO / p27Kip1-/- or ‘DKO’) mouse model in which a germ line p27Kip1 gene deletion (p27Kip1-/-) is combined with the T cell-restricted deletion of the Smad4 gene (Smad4TKO). All DKO mice develop spontaneous gastrointestinal inflammation and colon carcinoma by 1-2 months and 3 months of age, respectively. The p27Kip1 gene deletion, when combined with the T cell-restricted deletion of the Smad4 gene, leads to progressive inflammatory cytokine production (TNF-α, IFN-γ, iNOS, IL-6, IL-1β), activation of Stat1 and Stat3 and suppression of the expression of the tumor suppressor, 15-PGDH. Collectively our data suggest that p27Kip1 deficiency promotes gastrointestinal epithelial malignancy through both enhancement of proliferation of mucosal epithelial cells and through expansion of mucosal effector memory T cells. Citation Format: Sung Hee Choi, Byung-Gyu Kim, Letterio J. John. p27Kip1 suppression of colitis-associated colon cancer mediated through cell intrinsic function in both mucosal epithelia and mucosal T cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr LB-251. doi:10.1158/1538-7445.AM2014-LB-251

Assessment of the hamster cheek pouch as a model for radiation-induced oral mucositis, and evaluation of the protective effects of keratinocyte growth factor using this model

Purpose: Oral mucositis induced by radiotherapy impacts quality of life. Previous studies have reported on the use of the hamster as a model for radiation-induced oral mucositis; however, details regarding factors such as radiation dose response, effects on myeloperoxidase (MPO) activity and related histopathological changes remain unclear. In the present study using the hamster, we evaluated the dose dependency of radiation-induced oral mucositis and the effects of keratinocyte growth factor (palifermin).Methods: Oral mucositis was induced in the cheek pouch by X-irradiation using single doses in the range 20–50 Gy. To evaluate the protective effect of palifermin, administration was carried out (5 mg/kg) on days 1, 2 and 3 or on days 9, 10 and 11 after single irradiation at a dose of 40 Gy.Results: The oral mucositis score, MPO activity and histopathological findings of inflammation increased in a dose dependent manner. Palifermin treatment stimulated the proliferation of mucosal epithelial cells. Additionally, palifermin when administered on days 1, 2 and 3 after irradiation (40 Gy) reduced the severity of oral mucositis.Conclusions: The hamster was found to be a suitable model for radiation-induced oral mucositis, with excellent results regarding the evaluation of radiation dose response and drug reactivity.

Index of Suspicion

The reader is encouraged to write possible diagnoses for each case before turning to the discussion. We invite readers to contribute case presentations and discussions. Please inquire first by contacting Dr. Deepak Kamat at DKamat@med.wayne.edu. A 2-year-old boy with a history of eczema and food allergies to nuts and soy presents to the emergency department with a 10-day history of generalized edema. The swelling began in the periorbital area but soon progressed to involve his entire body. There have been no fevers or any recent illnesses other than 1 day of cough and a few watery stools. He has had no new exposures to foods or other substances. His family history is remarkable for multiple allergies and eczema. Physical examination reveals a temperature of 98.8°F (37.1oC), heart rate of 98 beats per minute, respiratory rate of 36 breaths per minute, blood pressure of 103/65 mm Hg, and an oxygen saturation of 97% on room air. His weight is 12.6 kg (34th percentile). He is noted to have a moderate amount of periorbital edema, decreased breath sounds at the lung bases bilaterally, a protuberant abdomen, and 2+ pitting edema on his lower extremities. The rest of his physical examination findings are within normal limits. Laboratory evaluation reveals a white blood cell count of 23,800/μL (23.8 × 109/L), with 37% neutrophils, 49% lymphocytes, 4% bands, 7% monocytes, and 3% eosinophils; hemoglobin level of 13.3 g/dL (133 g/L); and platelet count of 427 × 103/μL (427 × 109/L). Serum electrolyte, blood urea nitrogen, and creatinine levels are normal. Sodium level is 132 mEq/L (132 mmol/L). Serum albumin level is 1.7 g/dL (17 g/L) (reference range, 3.4-5.4 g/dL [34-54 g/L]). Total protein level is 3.8 g/dL (38 g/L). Aspartate aminotransferase, alanine aminotransferase, and coagulation profiles …

Keratinocyte growth factor phage model peptides can promote human oral mucosal epithelial cell proliferation

The objective of this study was to find keratinocyte growth factor (KGF) mimic peptides by a phage display library screening and to analyze their effects on proliferation of human oral mucosal epithelial cells (HOMECs). A phage display library was screened by anti-KGF antibody. ELISA was performed to select monoclonal phages with higher binding activity. The promotion of the phage model peptides on HOMEC proliferation were analyzed by MTT and their cell affinities were confirmed by immunofluorescence assay. Their effect on KGFR, human beta-defensin 3, c-Fos, and c-Jun in HOMEC were analyzed by quantitative real-time PCR. Two model peptides with higher affinity with HOMEC were found to have promotive activity on cell proliferation, similar to that of KGF. These 2 model peptides have no KGF-like promotion effect on the expression of c-Fos and c-Jun. The 2 phage model peptides can promote the proliferation of HOMEC in vitro without tumorigenic effects, which suggests their possible usages in oral mucosal wound healing.

Clopidogrel delays gastric ulcer healing in rats

Clopidogrel is not safe enough for the gastric mucosa in patients with high risk of peptic ulcer. This study aimed to explore if clopidogrel delays gastric ulcer healing and elucidate the involved mechanisms. Gastric ulcer was induced in rats and the ulcer size, mucosal epithelial cell proliferation of the ulcer margin, expression of growth factors [epidermal growth factor (EGF), basic fibroblast growth factor] and their receptors, and signal transduction pathways for cell proliferation were measured and compared between the clopidogrel-treated group and untreated controls. For the in vitro part, rat gastric mucosal epithelial cell line (RGM-1 cells) was used to establish EGF receptor over-expressed cells. Cell proliferation and molecular change under EGF treatment (10ng/ml) with and without clopidogrel (10−6M) were demonstrated. Ulcer size was significantly larger in the clopidogrel-treated group compared to the control and mucosal epithelial cell proliferation of the ulcer margin was significantly decreased in the clopidogrel-treated group (P<0.05). Clopidogrel (2mg and 10mg/kg/day) significantly decreased ulcer-induced gastric epithelial cell proliferation and ulcer-stimulated expressions of EGF receptor and phosphorylated extracellular signal-regulated kinase (PERK) at the ulcer margin (P<0.05). Clopidogrel (10−6M) also inhibited EGF-stimulated EGF receptor, PERK expression, and cell proliferation in RGM-1 cells (P<0.05), and caused much less inhibition of EGF-stimulated cell proliferation in EGF receptor over-expressed RGM-1 cells than in RGM-1 cells (22% vs. 32% reduction). In conclusion, clopidogrel delays gastric ulcer healing in rats via inhibiting gastric epithelial cell proliferation, at least by inhibition of the EGF receptor-ERK signal transduction pathway.

Effect of surgical trauma on apoptosis and proliferation of human oral mucosal epithelial cells

Objective To evaluate the effect of surgical trauma on apoptosis and proliferation of human oral mucosal epithelial (OME) cells.Methods OME cells from patients with breast-conserving surgery (n =10),and patients with breast cancer subject to radical surgery (n =13 ) were collected and analyzed by sub-G1 method and Ki-67 method.The proliferation rate and apoptosis rate were statistically analyzed before and after operation.Results Before operation,there was no significant difference in the age,sex and nutritional status between breast-conserving surgery and radical surgery groups,and the apoptosis rate and proliferation rate of OME cells were (27.51 ± 0.61 ) ％,(27.33 ± 0.53 ) ％ and ( 15.98 ±0.36) ％,( 16.04 ± 0.55 ) ％ ( P ＞ 0.05 ) respectively.After operation,there was also no significant difference in apoptosis rate [ (27.01 ± 0.46) ％ vs.(27.36 ± 0.50 ) ％ ] and proliferation rate [ ( 16.25 ±0.25 ) ％ vs.( 16.24 ± 0.64) ％ ] ( P ＞ 0.05 ) between breast-conserving surgery group and radical surgery group.Conclusion Surgical trauma has no effect on apoptosis and proliferation of OME cells in vivo. Key words: Surgical trauma; Oral mucosal cells; Proliferation

Administration of a dipeptidyl peptidase IV inhibitor enhances the intestinal adaptation in a mouse model of short bowel syndrome

Glucagon-like peptide-2 induces small intestine mucosal epithelial cell proliferation and may have benefit for patients who suffer from short bowel syndrome. However, glucagon-like peptide-2 is inactivated rapidly in vivo by dipeptidyl peptidase IV. Therefore, we hypothesized that selectively inhibiting dipeptidyl peptidase IV would prolong the circulating life of glucagon-like peptide-2 and lead to increased intestinal adaptation after development of short bowel syndrome. Eight-week old C57BL/6J mice underwent a 50% proximal small bowel resection and were treated with either sitagliptin, a dipeptidyl peptidase IV-inhibitor, starting 1 day before surgery versus placebo. The efficacy of dipeptidyl peptidase IV-inhibitor was assessed 3 days after resection, including intestinal morphology, epithelial cell apoptosis, and epithelial cell proliferation. Adaptive mechanisms were assessed with quantitative real-time polymerase chain reaction, and plasma bioactive glucagon-like peptide-2 was measured by radioimmunoassay. Body weight loss and peripheral blood glucose levels did not change compared with short bowel syndrome controls. Dipeptidyl peptidase IV-inhibitor treatment led to significant increases in villus height and crypt depth. Dipeptidyl peptidase IV-inhibitor treatment did not change EC apoptosis rates significantly, but it did increase crypt epithelial cell proliferation significantly versus placebo-short bowel syndrome controls. Dipeptidyl peptidase IV-inhibitor treatment markedly increased messenger RNA expression of β-catenin and c-myc in ileal mucosa. Plasma glucagon-like peptide-2 levels increased significantly (∼ 40.9%) in dipeptidyl peptidase IV-inhibitor short bowel syndrome mice. Dipeptidyl peptidase IV-inhibitor treatment increased short bowel syndrome adaptation and might potentially be useful for short bowel syndrome patients.

The Protective Role of Lychnophora ericoides Mart. (Brazilian Arnica) in 1,2-Dimethylhydrazine-Induced Experimental Colon Carcinogenesis

Aberrant crypt foci (ACF) and colon rectal mucosal epithelial cell proliferation have been shown to be increased in patients with colon cancer and have been largely used for early detection of factors that influence colorectal carcinogenesis in rats. Fifty male Wistar rats were randomly divided into 5 groups. The groups G1 to G4 were given 4 injections of the carcinogen 1,2-dimethylhydrazine (DMH). The G2 group received Lychnophora ericoides (LE) extracts for 6 wk. The groups G3 and G4 received LE for 4 wk and 2 wk, respectively, at the postinitiation and initiation phases of colonic carcinogenesis. The group G5 was the control. Forty-two days after the first injections of DMH for the neoplasic induction, we observed a statistically significant decrease in the number of aberrant crypt foci (ACF) and an attenuation of the increase in cell proliferation induced by DMH in all the LE-treated groups. Thus, we concluded that Lychnophora ericoides extracts were effective against the development of cancer. These data suggest that LE has a protective influence on the process of colon carcinogenesis, suppressing both the initiation and the promotion of colonic carcinogenesis.

Gastrointestinal tract mucosal histomorphometry and epithelial cell proliferation and apoptosis in neonatal and adult dogs

In this study, the hypothesis was tested that the size of gastrointestinal tract (GIT) mucosal components and rates of epithelial cell proliferation and apoptosis change with increasing age. The aims were to quantitatively examine GIT histomorphology and to determine mucosal epithelial cell proliferation and apoptosis rates in neonatal (<48 h old) and adult (8 to 11.5 yr old) dogs. Morphometrical analyses were performed by light microscopy with a video-based, computer-linked system. Cell proliferation and apoptosis of the GIT epithelium were evaluated by counting the number of Ki-67 and caspase-3-positive cells, respectively, using immunohistochemical methods. Thickness of mucosal, glandular, subglandular, submucosal and muscular layers, crypt depths, villus heights, and villus widths were consistently greater (P < 0.05 to P < 0.001), whereas villus height/crypt depth ratios were smaller (P < 0.001) in adult than in neonatal dogs. The number of Ki-67-positive cells in stomach, small intestine, and colon crypts, but not in villi, was consistently greater (P < 0.01) in neonatal than in adult dogs. In contrast, the number of caspase-3-positive cells in crypts of the stomach, small intestine, and colon and in villi was not significantly influenced by age. In conclusion, canine GIT mucosal morphology and epithelial cell proliferation rates, but not apoptosis rates, change markedly from birth until adulthood is reached.

Carbachol induces TGF-alpha expression and colonic epithelial cell proliferation in sensory-desensitised rats

Signals for the expression of the peptide growth factors epidermal growth factor and transforming growth factor-alpha (TGFalpha) in the gastrointestinal mucosa are largely unknown. We have shown earlier that extrinsic afferents in the gastrointestinal tract induce TGFalpha expression in colonic mucosa via the deliberation of neurotransmitters substance P and calcitonin gene-related peptide. The aim of our present study was to determine the effects of carbachol on mucosal TGFalpha expression and epithelial cell proliferation in vivo. Rats were divided in three groups. Group 1 was treated with vehicle only, group 2 received one single subcutaneous injection of 250 microg/kg of carbachol and animals in group 3 were sensory-desensitised prior to the injection of 250 microg/kg carbachol. TGFalpha expression and epithelial cell proliferation was evaluated by polymerase chain reaction, Western blot analysis and bromodeoxyuridine staining. Carbachol induced a significant increase in mucosal epithelial cell proliferation and TGFalpha expression. Sensory desensitisation did neither abolish the increased TGFalpha expression nor the increase in epithelial cell proliferation. Parasympathetic pathways are involved in the control of TGFalpha expression in gastrointestinal mucosa as well as in epithelial cell proliferation.

Effects of recombinant human growth hormone on enterocutaneous fistula patients

To explore the effects of recombinant human growth hormone (rhGH) on intestinal mucosal epithelial cell proliferation and nutritional status in patients with enterocutaneous fistula. Eight patients with enterocutaneous fistulas received recombinant human growth hormone (10 microg/d) for 7 d. Image analysis and immunohistochemical techniques were used to analyse the expression of proliferating cell nuclear antigen (PCNA) in intestinal mucosal epithelial cells in biopsy samples from the patients who had undergone an endoscopic biopsy through the fistula at day 0, 4 and 7. Body weights, nitrogen excretion, serum levels of total proteins, albumin, prealbumin, transferrin and fibronectin were measured at day 0, 4 and 7. Significant improvements occurred in the expression of PCNA in the intestinal mucosal epithelial cells at day 4 and 7 compared to day 0 (24.93 +/- 3.41%, 30.46 +/- 5.24% vs 12.92 +/- 4.20%, P < 0.01). These changes were accompanied by the significant improvement of villus height (500.54 +/- 53.79 microm, 459.03 +/- 88.98 microm vs 210.94 +/- 49.16 microm, P < 0.01), serum levels of total proteins (70.52 +/- 5.13 g/L, 74.89 +/- 5.16 g/L vs 63.51 +/- 2.47 g/L, P < 0.01), albumin (39.44 +/- 1.18 g/L, 42.39 +/- 1.68 g/L vs 35.74 +/- 1.75 g/L, P < 0.01) and fibronectin (236.3 +/- 16.5 mg/L, 275.8 +/- 16.9 mg/L vs 172.5 +/- 21.4 mg/L, P < 0.01) at day 4 and 7, and prealbumin (286.38 +/- 65.61 mg/L vs 180.88 +/- 48.28 mg/L, P < 0.05), transferrin (2.61 +/- 0.12 g/L vs 2.41 +/- 0.14 g/L, P < 0.05) at day 7. Nitrogen excretion was significantly decreased at day 7 (3.40 +/- 1.65 g/d vs 7.25 +/- 3.92 g/d, P < 0.05). No change was observed in the body weight. Recombinant human growth hormone could promote intestinal mucosal epithelial cell proliferation and protein synthesis in patients with enterocutaneous fistula.

Nimesulide Inhibits Crypt Epithelial Cell Proliferation at 6 Hours in the Small Intestine in CD-1 Mice

To determine whether the gut-sparing selectivity of cyclooxygenase-2 inhibitors is related to early crypt kinetic mechanisms, this study compared the primary effects on small intestinal mucosal epithelial cell proliferation and morphometry of a nonselective dual cyclooxygenase inhibitor, indomethacin, with a cyclooxygenase-2 selective inhibitor, nimesulide. Indomethacin downregulated the crypt cell production rate in the proximal small intestine, and nimesulide reduced cell proliferation in the proximal and distal small intestine. Compared to controls, there were smaller proliferating compartments in the crypts in midintestinal segments in both indomethacin- and nimesulide-treated groups, but more dividing cells in the distal intestine in indomethacin-treated group. Crypt cellularity, numbers, and width were unchanged from control values in both treated groups, suggesting a reduction in crypt cell emigration. Despite its selectivity for inhibiting cyclooxygenase-2, nimesulide induces similar but widespread initial effects on intestinal cell kinetics when compared to indomethacin.

Burn and starvation increase programmed cell death in small bowel epithelial cells.

Maintenance of gut mucosal homeostasis depends on a balance between cell proliferation and cell death. Gut mucosal integrity is impaired after severe burn and during starvation. We determined the effect of burn, starvation, and the combination of both on small bowel epithelial apoptosis and proliferation. Fifty adult male Fischer 344 rats (260-300 g) received a 60% full-thickness scald burn and were randomly divided into fed and starved groups. Small intestine was taken at 12, 24, and 48 hr after injury. All animals in the 12-hr group were starved while recovering from anesthesia. Apoptosis was quantified by immunohistochemical staining (TUNEL) and mucosal proliferation was determined by bromodeoxyuridine (BrdU) incorporation. The apoptotic index was higher in burned rats compared to controls at 12 hr after burn; both these groups were starved (P < 0.05). At 24 and 48 hr after burn, apoptosis was highest in the starved groups, with no additional effects of burn (P < 0.05). Mucosal epithelial cell proliferation was not different between groups at any time point. In conclusion, burn and starvation both increase apoptosis in the small bowel mucosa; however, these effects are not additive. Apoptosis could be attenuated by enteral feeding, which delineates the importance of early enteral feeding initiation after injury to maintain mucosal integrity.