[Mechanism of intestinal injury induced by WNT2B high-expressed fibroblasts in Crohn's disease]

Objective: To explore the mechanism of intestinal tissue damage induced by macrophages activated by WNT2B high-expressed fibroblasts. Methods: This study involved biological information analysis, pathological tissue research and cell experimental research. The biological information of the colon tissue from the children with inflammatory bowel disease in previous study was analyzed again with single-cell sequencing. The pathological tissues were collected by colonoscopy from 10 children with Crohn's disease treated in the Department of Gastroenterology of Guangzhou Women and Children's Medical Center from July 2022 to September 2022. According to the findings of colonoscopy, tissues with obvious inflammation or ulceration were classified as the inflammatory group, while tissues with slight inflammation and no ulceration were classified as the non-inflammatory group. HE staining was performed to observe the pathological changes of the colon tissues. Macrophage infiltration and CXCL12 expression were detected by immunofluorescence. In terms of cell experiments, fibroblasts transfected with WNT2B plasmid or empty plasmid were co-cultured with salinomycin treated or non-treated macrophages, respectively; the expression of proteins through Wnt classical pathway were detected by western blotting. Macrophages treated with SKL2001 were used as the experimental group, and those with phosphate buffer as the control group. The expression and secretion of CXCL12 in macrophages were detected by quantitative Real-time PCR and enzyme-linked immunosorbent assay (ELISA). T-test or rank sum test were used for the comparison between groups. Results: Single-cell sequencing analysis suggested that macrophages were the main cells in inflammatory bowel disease colon tissue, and there was interaction between WNT2B high-expressed fibroblasts and macrophages. HE staining of the 10 patients ((9.3±3.8) years old, 7 males and 3 females) showed that the pathological score of colon tissue in the inflammatory group was higher than that in the non-inflammatory group (4 (3, 4) vs. 2 (1, 2) points, Z=3.05, P=0.002). Tissue immunofluorescence indicated that the number of infiltrating macrophages in the inflammatory group was significantly higher than that in the non-inflammatory group under high power field of view (72.8±10.4 vs.8.4±3.5, t=25.10, P<0.001), as well as the number of cells expressing CXCL12 (14.0±3.5 vs. 4.7±1.9, t=14.68, P<0.001). In cell experiments, western blotting suggested an elevated level of glycogen synthase kinase-3β phosphorylation in macrophages co-cultured with fibroblast transfected with WNT2B plasmid, and salinmycin could reverse this change. Real-time PCR suggested that the transcription level of CXCL12 in the experimental group was higher than that in the control group (6.42±0.04 vs. 1.00±0.03, t=183.00, P<0.001), as well as the expression and secretion of CXCL12 by ELISA ((465±34) vs. (77±9) ng/L, t=13.21, P=0.006). Conclusion: WNT2B high-expressed fibroblasts can secrete WNT2B protein and activate the Wnt classical signaling pathway thus enhancing the expression and secretion of CXCL12 in macrophages, inducing the development of intestinal inflammation of Crohn's disease.

[Efficacy and safety of endoscopic diaphragm incision in children with congenital duodenal diaphragm]

Objective: To explore the efficacy and safety of endoscopic diaphragm incision in pediatric congenital duodenal diaphragm. Methods: Eight children with duodenal diaphragm treated by endoscopic diaphragm incision in the Department of Gastroenterology of Guangzhou Women and Children's Medical Center from October 2019 to May 2022 were enrolled in this study. Their clinical data including general conditions, clinical manifestations, laboratory and imaging examinations, endoscopic procedures and outcomes were retrospectively analyzed. Results: Among the 8 children, 4 were males and 4 females. The diagnosis was confirmed at the age of 6-20 months; the age of onset was 0-12 months and the course of disease was 6-18 months. The main clinical manifestations were recurrent non-biliary vomiting, abdominal distension and malnutrition. One case complicated with refractory hyponatremia was first diagnosed with atypical congenital adrenal hyperplasia in the endocrinology department. After treatment with hydrocortisone, the blood sodium returned to normal, but vomiting was recurrent. One patient underwent laparoscopic rhomboid duodenal anastomosis in another hospital but had recurred vomiting after the operation, who was diagnosed with double duodenal diaphragm under endoscope. No other malformations were found in all the 8 cases. The duodenal diaphragm was located in the descending part of the duodenum, and the duodenal papilla was located below the diaphragm in all the 8 cases. Three cases had the diaphragm dilated by balloon to explore the diaphragm opening range before diaphragm incision; the other 5 had diaphragm incision performed after probing the diaphragm opening with guide wire. All the 8 cases were successfully treated by endoscopic incision of duodenal diaphragm, with the operation time of 12-30 minutes. There were no complications such as intestinal perforation, active bleeding or duodenal papilla injury. At one month of follow-up, their weight increased by 0.4-1.5 kg, with an increase of 5%-20%. Within the postoperative follow-up period of 2-20 months, all the 8 children had duodenal obstruction relieved, without vomiting or abdominal distension, and all resumed normal feeding. Gastroscopy reviewed at 2-3 months after the operation in 3 cases found no deformation of the duodenal bulbar cavity, and the mucosa of the incision was smooth, with a duodenal diameter of 6-7 mm. Conclusion: Endoscopic diaphragm incision is safe, effective and less invasive in pediatric congenital duodenal diaphragm, with favorable clinical applicability.