P165 Non-invasive biomarkers of type III collagen cross-linking reflects fibrolysis in patient with luminal CROHN’S DISEASE

Background Type III collagen of the interstitial matrix is highly expressed in fibrotic tissue of Crohn’s disease (CD) and suggested to undergo remodelling during the characteristic deep tissue inflammation. Periods of inflammatory flares and remission could thus be reflected by varying degrees of type III collagen degradation and formation in relation to fibrogenesis and resolution of fibrosis. The aim was to investigate the association between type III collagen remodelling and CD disease phenotypes based on the Montreal classification Methods 40 CD patients were endoscopically assessed according to the Montreal B classification (luminal or stricturing phenotype) and Harvey Bradshaw Index for clinical disease activity (<4 = inactive; >4 = active). Patients were stratified based on both the Montreal B classification and HBI scores. Biomarkers were assessed by ELISA: 1) CTX-III (cross-linked protease degraded fragments of type III collagen), PC3X (cross-linked type III collagen formation), 3) PRO-C3 (type III collagen formation), and 4) C3M (MMP-9 degradation fragments) Results Biomarker levels of CTX-III was significantly elevated in CD patients with luminal- and clinically inactive- disease compared to patients with stricturing- and clinically inactive- disease and luminal- and clinically active- disease (p<0.01 and p<0.05, fig 1A). The levels of net fibrolysis of cross-linked type III collagen (CTX-III/PC3X) was significantly higher in patients with luminal- and clinically inactive- disease compared to patients with stricturing- and clinically inactive- disease (p<0.001), luminal- and clinically active- disease (p<0.001), and patients with stricturing- and clinically active- disease (p<0.05, fig 1C). Significantly elevated levels of net type III collagen degradation (C3M/PRO-C3) were observed in patients with a luminal- and clinically active- disease compared to luminal- and clinically inactive- as well as stricturing- and clinically inactive- disease (p<0.05). Furthermore, net type III collagen degradation was elevated compared to patients with stricturing- and clinically active- disease (p<0.05, fig 1F). Biomarker levels of PC3X, C3M, and PRO-C3 were unable to differentiate between patient groupings (fig 1B, D, and E) Conclusion Proteolytic degradation of cross-linked type III collagen (CTX-III) reflecting resolution of fibrosis in CD patients with luminal disease, may be associated with a protective effect against fibrogenesis and progression to fibrostenosis. These data indicate differences in cross-linked and non-cross-linked type III collagen remodelling in CD patients, and their potential use for differentiating patient phenotypes and disease activity

Endothelial Cell-Derived SO2 Controls Endothelial Cell Inflammation, Smooth Muscle Cell Proliferation, and Collagen Synthesis to Inhibit Hypoxic Pulmonary Vascular Remodelling

Hypoxic pulmonary vascular remodelling (PVR) is the major pathological basis of aging-related chronic obstructive pulmonary disease and obstructive sleep apnea syndrome. The pulmonary artery endothelial cell (PAEC) inflammation, and pulmonary artery smooth muscle cell (PASMC) proliferation, hypertrophy and collagen remodelling are the important pathophysiological components of PVR. Endogenous sulfur dioxide (SO2) was found to be a novel gasotransmitter in the cardiovascular system with its unique biological properties. The study was aimed to investigate the role of endothelial cell- (EC-) derived SO2 in the progression of PAEC inflammation, PASMC proliferation, hypertrophy and collagen remodelling in PVR and the possible mechanisms. EC-specific aspartic aminotransferase 1 transgenic (EC-AAT1-Tg) mice were constructed in vivo. Pulmonary hypertension was induced by hypoxia. Right heart catheterization and echocardiography were used to detect mouse hemodynamic changes. Pathologic analysis was performed in the pulmonary arteries. High-performance liquid chromatography was employed to detect the SO2 content. Human PAECs (HPAECs) with lentiviruses containing AAT1 cDNA or shRNA and cocultured human PASMCs (HPASMCs) were applied in vitro. SO2 probe and enzyme-linked immunosorbent assay were used to detect the SO2 content and determine p50 activity, respectively. Hypoxia caused a significant reduction in SO2 content in the mouse lung and HPAECs and increases in right ventricular systolic pressure, pulmonary artery wall thickness, muscularization, and the expression of PAEC ICAM-1 and MCP-1 and of PASMC Ki-67, collagen I, and α-SMA ( p < 0.05 ). However, EC-AAT1-Tg with sufficient SO2 content prevented the above increases induced by hypoxia ( p < 0.05 ). Mechanistically, EC-derived SO2 deficiency promoted HPAEC ICAM-1 and MCP-1 and the cocultured HPASMC Ki-67 and collagen I expression, which was abolished by andrographolide, an inhibitor of p50 ( p < 0.05 ). Meanwhile, EC-derived SO2 deficiency increased the expression of cocultured HPASMC α-SMA ( p < 0.05 ). Taken together, these findings revealed that EC-derived SO2 inhibited p50 activation to control PAEC inflammation in an autocrine manner and PASMC proliferation, hypertrophy, and collagen synthesis in a paracrine manner, thereby inhibiting hypoxic PVR.

The novel zebrafish model pretzel demonstrates a central role for SH3PXD2B in defective collagen remodelling and fibrosis in Frank-Ter Haar syndrome

ABSTRACTFrank-Ter Haar syndrome (FTHS, MIM #249420) is a rare skeletal dysplasia within the defective collagen remodelling spectrum (DECORS), which is characterised by craniofacial abnormalities, skeletal malformations and fibrotic soft tissues changes including dermal fibrosis and joint contractures. FTHS is caused by homozygous or compound heterozygous loss-of-function mutation or deletion of SH3PXD2B (Src homology 3 and Phox homology domain-containing protein 2B; MIM #613293). SH3PXD2B encodes an adaptor protein with the same name, which is required for full functionality of podosomes, specialised membrane structures involved in extracellular matrix (ECM) remodelling. The pathogenesis of DECORS is still incompletely understood and, as a result, therapeutic options are limited. We previously generated an mmp14a/b knockout zebrafish and demonstrated that it primarily mimics the DECORS-related bone abnormalities. Here, we present a novel sh3pxd2b mutant zebrafish, pretzel, which primarily reflects the DECORS-related dermal fibrosis and contractures. In addition to relatively mild skeletal abnormalities, pretzel mutants develop dermal and musculoskeletal fibrosis, contraction of which seems to underlie grotesque deformations that include kyphoscoliosis, abdominal constriction and lateral folding. The discrepancy in phenotypes between mmp14a/b and sh3pxd2b mutants suggests that in fish, as opposed to humans, there are differences in spatiotemporal dependence of ECM remodelling on either sh3pxd2b or mmp14a/b. The pretzel model presented here can be used to further delineate the underlying mechanism of the fibrosis observed in DECORS, as well as screening and subsequent development of novel drugs targeting DECORS-related fibrosis.This paper has an associated First Person interview with the first author of the article.