Responsiveness of intestinal epithelial cell turnover to TGF-alpha after bowel resection in a rat is correlated with EGF receptor expression along the villus-crypt axis

Nutrition and Intestinal Rehabilitation of Children With Short Bowel Syndrome: A Position Paper of the ESPGHAN Committee on Nutrition. Part 1: From Intestinal Resection to Home Discharge

Short bowel syndrome (SBS) is the leading cause of intestinal failure (IF) in children. The mainstay of treatment for IF is parenteral nutrition (PN). The aim of this position paper is to review the available evidence on managing SBS and to provide practical guidance to clinicians dealing with this condition. All members of the Nutrition Committee of the European Society for Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) contributed to this position paper. Some renowned experts in the field joined the team to guide with their experience. A systematic literature search was performed from 2005 to May 2021 using PubMed, MEDLINE, and Cochrane Database of Systematic Reviews. In the absence of evidence, recommendations reflect the expert opinion of the authors. Literature on SBS mainly consists of retrospective single-center experience, thus most of the current papers and recommendations are based on expert opinion. All recommendations were voted on by the expert panel and reached >90% agreement. The first part of this position paper focuses on the physiological mechanism of intestinal adaptation after surgical resection. It subsequently provides some clinical practice recommendations for the primary management of children with SBS from surgical resection until discharged home on PN.

Adaptation of extracellular matrix to massive small bowel resection in mice

BACKGROUND

Extracellular matrix (ECM) affects cell behavior, and vice versa. How ECM changes after small bowel resection (SBR) to support adaptive cellular processes has not been described. Here we characterize changes in ECM following SBR and integrate this with concomitant transcriptional perturbations.

METHODS

A 50% proximal SBR or sham surgery was performed on mice. On postoperative day 7, ileal tissue was sequentially depleted of protein components to generate an ECM-enriched fraction. ECM was analyzed for protein composition using mass spectrometry with subsequent Ingenuity Pathway Analysis (IPA) to identify predicted pathways and upstream regulators. qPCR and RNA-sequencing (RNA-Seq) were performed to corroborate these predicted pathways.

RESULTS

3034 proteins were differentially regulated between sham and SBR, of which 95 were significant (P < 0.05). IPA analysis predicted PPARα agonism to be an upstream regulator of the observed proteomic changes (P < 0.001). qPCR and RNA-Seq with KEGG analysis confirmed significant engagement of the PPAR pathway (P < 0.05).

CONCLUSION

Transcriptional signatures of adapting bowel predict subsequent ECM changes after SBR. How ECM communicates with surrounding cells to drive adaptation and vice versa merits further investigation. Our findings thus far suggest ECM supports tissue hyperplasia and altered metabolic demand following SBR.

Host-Gut Microbiota Crosstalk in Intestinal Adaptation

Short-bowel syndrome represents the most common cause of intestinal failure and occurs when the remaining intestine cannot support fluid and nutrient needs to sustain adequate physiology and development without the use of supplemental parenteral nutrition. After intestinal loss or damage, the remnant bowel undergoes multifactorial compensatory processes, termed adaptation, which are largely driven by intraluminal nutrient exposure. Previous studies have provided insight into the biological processes and mediators after resection, however, there still remains a gap in the knowledge of more comprehensive mechanisms that drive the adaptive responses in these patients. Recent data support the microbiota as a key mediator of gut homeostasis and a potential driver of metabolism and immunomodulation after intestinal loss. In this review, we summarize the emerging ideas related to host-microbiota interactions in the intestinal adaptation processes.

The correlation between microRNA490-3p and TGFα in endometrial carcinoma tumorigenesis and progression

MicroRNAs (miRNAs) are small non-coding RNAs that negatively regulate the translation of messenger RNAs by binding their 3′-untranslated region (3′ UTR). MiR-490-3p has been reported to be a suppressor in various human cancers; however, little is known about the biological functions of miR-490-3p in endometrial cancer (EC). In our study, we found that MiR-490-3p mRNA expression was significantly lower in ECs than in normal endometrial tissues. MiR-490-3p mRNA expression was also negatively associated with depth of invasion (mucosa vs. muscular and serosa) and lymph node metastasis (negative vs. positive) in EC. MiR-490-3p overexpression reduced proliferation; promoted G1 arrest and apoptosis; suppressed migration and invasion; and reduced TGFα, NF-kB, cyclin D1, survivin, matrix metalloproteinase 2 (MMP2) mRNA and protein expression, and improved Bax mRNA and protein expression. The dual-luciferase reporter assay indicated that miR-490-3p directly targeted TGFα by binding its 3′ untranslated region. MiR-490-3P transfection also suppressed tumor development and TGFα expression (as determined by immunohistochemistry and western blotting) in vivo in the xenograft mouse model. This is the first demonstration that miR-490-3P might act as a suppressor in EC tumorigenesis and progression by targeting TGFα. Our results provide a theoretical basis for the further study on the molecular target for endometrial cancer.

PDGF-α stimulates intestinal epithelial cell turnover after massive small bowel resection in a rat

Numerous cytokines have been shown to affect epithelial cell differentiation and proliferation through epithelial-mesenchymal interaction. Growing evidence suggests that platelet-derived growth factor (PDGF) signaling is an important mediator of these interactions. The purpose of this study was to evaluate the effect of PDGF-α on enterocyte turnover in a rat model of short bowel syndrome (SBS). Male rats were divided into four groups: Sham rats underwent bowel transection, Sham-PDGF-α rats underwent bowel transection and were treated with PDGF-α, SBS rats underwent a 75% bowel resection, and SBS-PDGF-α rats underwent bowel resection and were treated with PDGF-α. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined at euthanasia. Illumina's Digital Gene Expression analysis was used to determine PDGF-related gene expression profiling. PDGF-α and PDGF-α receptor (PDGFR-α) expression was determined by real-time PCR. Western blotting was used to determine p-ERK, Akt1/2/3, bax, and bcl-2 protein levels. SBS rats demonstrated a significant increase in PDGF-α and PDGFR-α expression in jejunum and ileum compared with sham animals. SBS-PDGF-α rats demonstrated a significant increase in bowel and mucosal weight, villus height, and crypt depth in jejunum and ileum compared with SBS animals. PDGF-α receptor expression in crypts increased in SBS rats (vs. sham) and was accompanied by an increased cell proliferation following PDGF-α administration. A significant decrease in cell apoptosis in this group was correlated with lower bax protein levels. In conclusion, in a rat model of SBS, PDGF-α stimulates enterocyte turnover, which is correlated with upregulated PDGF-α receptor expression in the remaining small intestine.

A diet containing whey protein, glutamine, and TGFbeta modulates gut protein metabolism during chemotherapy-induced mucositis in rats

BACKGROUND

Mucositis, a common side effect of chemotherapy, is characterized by compromised digestive function, barrier integrity and immune competence.

AIMS

Our aim was to evaluate the impact of a specifically designed diet Clinutren Protect (CP), which contains whey proteins, TGFbeta-rich casein, and free glutamine, on mucositis in rats.

METHODS

Mucositis was induced by three consecutive injections (day 0, day 1, day 2) of methotrexate (2.5 mg/kg). Rats had free access to CP or placebo diets from days -7 to 9. In the placebo diet, whey proteins and TGFbeta-rich casein were replaced by TGFbeta-free casein and glutamine by alanine. Intestinal parameters were assessed at day 3 and 9. Values, expressed as mean +/- SEM, were compared using two-way ANOVA.

RESULTS

At day 3, villus height was markedly decreased in the placebo (296 +/- 11 microm) and CP groups (360 +/- 10 microm) compared with controls (464 +/- 27 microm), but more markedly in the placebo as compared to CP group. The intestinal damage score was also reduced in the CP compared with the placebo group. Glutathione content increased in the CP compared with the placebo group (2.2 +/- 0.2 vs. 1.7 +/- 0.2 micromol/g tissue). Gut protein metabolism was more affected in the placebo than in the CP group. The fractional synthesis rate was decreased in the placebo group (93.8 +/- 4.9%/day) compared with controls (121.5 +/- 12.1, P < 0.05), but not in the CP group (106.0 +/- 13.1). In addition, at day 9, rats exhibited improved body weight and food intake recovery in the CP compared to the placebo group.

CONCLUSIONS

Clinutren Protect feeding reduces intestinal injury in the acute phase of methotrexate-induced mucositis in rats and improves recovery.

Oral insulin stimulates intestinal epithelial cell turnover in correlation with insulin-receptor expression along the villus-crypt axis in a rat model of short bowel syndrome

PURPOSE

It has been reported that oral insulin (OI) has a trophic effect on intestinal mucosa. In the present study, we evaluated the effect of OI on enterocyte turnover and correlated it with insulin-receptor expression along the villus-crypt axis in a rat model of short bowel syndrome (SBS).

METHODS

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 fourth 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 insulin receptor-beta (IRB) mRNA. Insulin-receptor expression along the villus-crypt axis (villus tips, lateral villi and crypts) was assessed by immunohistochemistry. The effect of OI on cell turnover for each compartment was evaluated in correlation with the receptor expression. Statistical analysis was performed using the one-way ANOVA test, with P < 0.05 considered statistically significant.

RESULTS

Treatment with OI resulted in a significant increase in all parameters of intestinal adaptation. Insulin-receptor expression in crypts significantly increased in SBS rats (vs. Sham rats) and was accompanied by a significant increase in enterocyte proliferation following OI administration. A significant increase in insulin-receptor expression at the tip of the villous and in the lateral villous in SBS rats (vs. Sham) was accompanied by decreased cell apoptosis in these compartments following treatment with OI.

CONCLUSIONS

In a rat model of SBS, OI enhances enterocyte turnover and stimulates intestinal adaptation. The stimulating effect of insulin on enterocyte turnover correlates with insulin-receptor expression along the villus-crypt axis.

Leptin affects intestinal epithelial cell turnover in correlation with leptin receptor expression along the villus-crypt axis after massive small bowel resection in a rat

In this study, we examine the responsiveness of intestinal epithelial cell turnover to leptin (LEP) in correlation with leptin receptor (LEPr) expression along the villus-crypt axis in a rat with short bowel syndrome (SBS). Adult rats underwent either a 75% intestinal resection or a transection. SBS-LEP rats underwent bowel resection and were treated with LEP starting from the fourth postoperative day. Parameters of intestinal adaptation, enterocyte proliferation, and enterocyte apoptosis were determined at sacrifice. RT-PCR technique was used to determine Bax and Bcl-2 gene expression in ileal mucosa. Villus tips, lateral villi, and crypts were separated using laser capture microdissection. LEPr expression for each compartment was assessed by quantitative real-time PCR (Taqman). Treatment with LEP significantly stimulated all parameters of adaptation. LEPr expression in crypts significantly increased in SBS rats (vs Sham rats) and was accompanied by a significant increase in enterocyte proliferation and decreased apoptosis after LEP administration. A significant increase in LEPr expression at the tip of the villus in SBS rats was accompanied by decreased cell apoptosis. In conclusion LEP accelerated enterocyte turnover and stimulated intestinal adaptation. The effect of LEP on enterocyte proliferation and enterocyte apoptosis correlated with receptor expression along the villus-crypt axis.