Mechanical stress-induced connective tissue growth factor plays a critical role in intestinal fibrosis in Crohn's-like colitis.

Crohn's disease (CD) is an inflammatory bowel disease characterized by transmural inflammation and intestinal fibrosis. Mechanisms of fibrosis in CD are not well understood. Transmural inflammation is associated with inflammatory cell infiltration, stenosis, and distention, which present mechanical stress (MS) to the bowel wall. We hypothesize that MS induces gene expression of profibrotic mediators such as connective tissue growth factor (CTGF), which may contribute to fibrosis in CD. A rodent model of CD was induced by intracolonic instillation of TNBS to the distal colon. TNBS instillation induced a localized transmural inflammation (site I), with a distended colon segment (site P) proximal to site I. We detected significant fibrosis and collagen content not only in site I but also in site P in CD rats by day 7. CTGF expression increased significantly in sites P and I, but not in the segment distal to the inflammation site. Increased CTGF expression was detected mainly in the smooth muscle cells (SMCs). When rats were fed exclusively with clear liquid diet to prevent mechanical distention in colitis, expression of CTGF in sites P and I was blocked. Direct stretch led to robust expression of CTGF in colonic SMC. Treatment of CD rats with anti-CTGF antibody FG-3149 reduced fibrosis and collagen content in both sites P and I and exhibited consistent trends toward normalizing expression of collagen mRNAs. In conclusion, our studies suggest that mechanical stress, by upregulating profibrotic mediators, i.e., CTGF, may play a critical role in fibrosis in CD.NEW & NOTEWORTHY We found that CTGF expression increased significantly not only in the inflammation site but in the distended segment proximal to inflammation in a rodent model of CD-like colitis. Release of mechanical distention prevented CTGF expression in CD rats, whereas direct stretch induced CTGF expression. Treatment with anti-CTGF antibody reduced fibrosis and collagen contents in CD rats. Thus, mechanical stress, via upregulating profibrotic mediators, i.e., CTGF, may play a critical role in fibrosis in CD.

DNA variants detected in primary and metastatic lung adenocarcinoma: a case report and review of the literature.

Non-small cell lung cancer (NSCLC) has been found to have recurrent genetic abnormalities, and novel therapies targeting these aberrations have improved patient survival. In this study, specimens from benign tissue, primary tumors, and brain metastases were obtained at autopsy from a 55-year-old White female patient diagnosed with NSCLC and were examined using next-generation sequencing (NGS) and chromosomal microarray assay (CMA). No genetic aberrations were noted in the benign tissue; however, NGS identified a mutation in the KRAS proto-oncogene, GTPase (KRAS): KRAS exon 2 p.G12D in primary and metastatic tumor specimens. We observed 7 DNA copy number aberrations (CNAs) in primary and metastatic tumor specimens; an additional 7 CNAs were exclusively detected in the metastatic tumor specimens. These DNA alterations may be genetic drivers in the pathogenesis of the tumor specimen from our patient and may serve as biomarkers for the classification and prognosis of NSCLC.