ABSTRACT
Intestinal fibrosis associated stricture is a common complication of inflammatory bowel disease usually requiring endoscopic or surgical intervention. Effective anti-fibrotic agents aiming to control or reverse intestinal fibrosis are still unavailable. Thus, clarifying the mechanism underpinning intestinal fibrosis is imperative. Fibrosis is characterized by an excessive accumulation of extracellular matrix (ECM) proteins at the injured sites. Multiple cellular types are implicated in fibrosis development. Among these cells, mesenchymal cells are major compartments that are activated and then enhance the production of ECM. Additionally, immune cells contribute to the persistent activation of mesenchymal cells and perpetuation of inflammation. Molecules are messengers of crosstalk between these cellular compartments. Although inflammation is necessary for fibrosis development, purely controlling intestinal inflammation cannot halt the development of fibrosis, suggesting that chronic inflammation is not the unique contributor to fibrogenesis. Several inflammation-independent mechanisms including gut microbiota, creeping fat, ECM interaction, and metabolic reprogramming are involved in the pathogenesis of fibrosis. In the past decades, substantial progress has been made in elucidating the cellular and molecular mechanisms of intestinal fibrosis. Here, we summarized new discoveries and advances of cellular components and major molecular mediators that are associated with intestinal fibrosis, aiming to provide a basis for exploring effective anti-fibrotic therapies in this field.
ABSTRACT
Objective To analyze the feasibility of incorporation of tracking visual pathway fiber bundles by diffusion tensor imaging ( DTI) in computed tomography ( CT) simulation to develop a protective radiotherapy regimen for cerebral gliomas.Methods A total of 31 patients with cerebral gliomas who were admitted to our hospital from 2013 to 2015 and planed to receive postoperative radiotherapy were enrolled as subjects.All patients underwent CT simulation, conventional or contrast-enhanced magnetic resonance imaging, and DTI.The obtained DTI images of visual pathway fiber bundles were fused with 3DT1 anatomical scans and then imported into the treatment planning system.A protective treatment plan ( setting the entire visual pathway fiber bundles as organs at risk (OARs)) and a conventional treatment plan were made for intensity-modulated radiotherapy ( IMRT) .Comparison of treatment outcomes was made by paired t test.Results There were no significant differences in the conformity index and heterogeneity index of the planning target volume between the two treatment plans ( P=0.875,0.597), both of which had sufficient radiation doses to the target volume and conventional OARs protected.For the patients undergoing the protective treatment plan, the Dmax and Dmean values were reduced to 9.01%and 9.05%, respectively, in the ipsilateral optic tract and to 17.96%and 15.52%, respectively, in the contralateral optic tract;the Dmax and Dmean values were reduced to 5.37%and 5.48%(P=0.000), respectively, in the ipsilateral optic radiation tract and to 12.89%and 11.21%( P=0.000) , respectively, in the contralateral optic radiation tract.Conclusions The protective treatment plan based on CT simulation combined with the display of visual pathway fiber bundles by DTI can reduce the radiation dose to the entire visual pathway fiber bundles, which keeps the risk of visual dysfunction after radiotherapy as low as possible.