The prevalence of long COVID-19 syndrome in hospitalized patients with COVID-19 pneumonia.

Introduction: Long COVID affects millions of individuals worldwide with a wide range of persistent symptoms. Pathogenesis, prevalence and clinical approach of this syndrome remain not well characterized.The aim of the study is the estimation of prevalence of long-COVID and identification of possible risk factors. Patients and Methods: This is an observational prospective study including COVID-19 patients hospitalized at the Department of Infectious Diseases of the University General Hospital of Alexandroupolis (Greece). Eligible COVID-19 patients were interviewed and examined 6, 12 and 18 months after COVID-19 symptoms onset and hospital discharge in order to evaluate the prevalence and consequences of long-COVID symptoms. Results: A total number of 995 patients were included. The median age at discharge was 55 years and 53% of patients were retired. The majority was males (57%). Vaccination against SARS-CoV-2 was completed in 52% (n=517) COVID-19 patients. More than 40% of COVID-19 patients had at least one symptom at 18 months after hospitalization. Intravenous antiviral 0treatment with remdesivir and complete vaccination status were found to lead to lower rates of Long-COVID. Conclusions: More studies in larger patient cohorts are needed in order to identify the underlying biological mechanisms of long-COVID and create effective interventions for prevention and treatment.

Exploring the Gut Microbiome's Role in Inflammatory Bowel Disease: Insights and Interventions.

Inflammatory Bowel Disease (IBD), encompassing Crohn's disease (CD) and ulcerative colitis (UC), is a chronic and relapsing inflammatory condition of the intestine that significantly impairs quality of life and imposes a heavy burden on healthcare systems globally. While the exact etiology of IBD is unclear, it is influenced by genetic, environmental, immunological, and microbial factors. Recent advances highlight the gut microbiome's pivotal role in IBD pathogenesis. The microbial dysbiosis characteristic of IBD, marked by a decline in beneficial bacteria and an increase in pathogenic microbes, suggests a profound connection between microbial imbalance and disease mechanisms. This review explores diagnostic approaches to IBD that integrate clinical assessment with advanced microbiological analyses, highlighting the potential of microbiome profiling as a non-invasive diagnostic tool. In addition, it evaluates conventional and emerging treatments and discusses microbiome-targeted intervention prospects, such as probiotics, symbiotics, and faecal microbiota transplantation. The necessity for future research to establish their efficacy and safety is emphasised.

Oncostatin M Induces a Pro-inflammatory Phenotype in Intestinal Subepithelial Myofibroblasts.

BACKGROUND: Oncostatin-M (OSM) is associated with antitumor necrosis factor (anti-TNF)-α resistance in inflammatory bowel disease (IBD) and fibrosis in inflammatory diseases. We studied the expression of OSM and its receptors (OSMR, gp130) on intestinal subepithelial myofibroblasts (SEMFs) and the effect of OSM stimulation on SEMFs. METHODS: The mRNA and protein expression of OSM, OSMR, gp130, and several fibrotic and chemotactic factors were studied in mucosal biopsies and isolated human intestinal SEMFs of patients with IBD and healthy controls (HCs) and in a model of human intestinal organoids (HIOs). Subepithelial myofibroblasts and HIOs were stimulated with OSM and interleukin (IL)-1α/TNF-α. RNAseq data of mucosal biopsies were also analyzed. RESULTS: Oncostatin-M receptors and gp130 were overexpressed in mucosal biopsies of patients with IBD (P < .05), especially in inflamed segments (P < .05). The expression of OSM, OSMR, and gp130 in SEMFs from HCs was increased after stimulation with IL-1α/TNF-α (P < .001; P < .01; P < .01). The expression of CCL2, CXCL9, CXCL10, and CXCL11 was increased in SEMFs from patients with IBD and HCs after stimulation with OSM in a dose-dependent manner (P < .001; P < .05; P < .001; P < .001) and was further increased after prestimulation with IL-1α/TNF-α (P < .01 vs OSM-alone). Similar results were yielded after stimulation of HIOs (P < .01). Oncostatin-M did not induce the expression of collagen I, III, and fibronectin. Oncostatin-M receptor expression was positively correlated with CCL2, CXCL9, CXCL10, and CXCL11 expression in mucosal biopsies (P < .001; P < .001; P = .045; P = .033). CONCLUSIONS: Human SEMFs overexpress OSMR in an inflammatory microenvironment. Oncostatin-M may promote inflammation in IBD via its stimulatory effects on SEMFs, which primarily involve chemoattraction of immune cells to the intestinal mucosa.

Oncostatin-M/OSMR show elevated expression on intestinal fibroblasts that is regulated by IBD-relevant pro-inflammatory stimuli. In turn, OSM induces a pro-inflammatory phenotype on primary intestinal fibroblasts, with prominent overexpression of chemotactic factors, without demonstrating a substantial profibrotic effect.

Exploring Microbial Metabolite Receptors in Inflammatory Bowel Disease: An In Silico Analysis of Their Potential Role in Inflammation and Fibrosis.

Metabolites produced by dysbiotic intestinal microbiota can influence disease pathophysiology by participating in ligand-receptor interactions. Our aim was to investigate the differential expression of metabolite receptor (MR) genes between inflammatory bowel disease (IBD), healthy individuals (HIs), and disease controls in order to identify possible interactions with inflammatory and fibrotic pathways in the intestine. RNA-sequencing datasets containing 643 Crohn's disease (CD) patients, 467 ulcerative colitis (UC) patients and 295 HIs, and 4 Campylobacter jejuni-infected individuals were retrieved from the Sequence Read Archive, and differential expression was performed using the RaNA-seq online platform. The identified differentially expressed MR genes were used for correlation analysis with up- and downregulated genes in IBD, as well as functional enrichment analysis using a R based pipeline. Overall, 15 MR genes exhibited dysregulated expression in IBD. In inflamed CD, the hydroxycarboxylic acid receptors 2 and 3 (HCAR2, HCAR3) were upregulated and were associated with the recruitment of innate immune cells, while, in the non-inflamed CD ileum, the cannabinoid receptor 1 (CNR1) and the sphingosine-1-phospate receptor 4 (S1PR4) were downregulated and were involved in the regulation of B-cell activation. In inflamed UC, the upregulated receptors HCAR2 and HCAR3 were more closely associated with the process of TH-17 cell differentiation, while the pregnane X receptor (NR1I2) and the transient receptor potential vanilloid 1 (TRPV1) were downregulated and were involved in epithelial barrier maintenance. Our results elucidate the landscape of metabolite receptor expression in IBD, highlighting associations with disease-related functions that could guide the development of new targeted therapies.

The Networked Interaction between Probiotics and Intestine in Health and Disease: A Promising Success Story.

Probiotics are known to promote human health either precautionary in healthy individuals or therapeutically in patients suffering from certain ailments. Although this knowledge was empirical in past tomes, modern science has already verified it and expanded it to new limits. These microorganisms can be found in nature in various foods such as dairy products or in supplements formulated for clinical or preventive use. The current review examines the different mechanisms of action of the probiotic strains and how they interact with the organism of the host. Emphasis is put on the clinical therapeutic use of these beneficial microorganisms in various clinical conditions of the human gastrointestinal tract. Diseases of the gastrointestinal tract and particularly any malfunction and inflammation of the intestines seriously compromise the health of the whole organism. The interaction between the probiotic strains and the host's microbiota can alleviate the clinical signs and symptoms while in some cases, in due course, it can intervene in the underlying pathology. Various safety issues of the use of probiotics are also discussed.

Remission of refractory Crohn's disease with anti-IL-12/23 therapy in a patient undergoing hemodialysis: A case report.

Crohn's disease is a relapsing chronic inflammatory condition of the intestine with increasing prevalence around the world. Biologic therapies are currently widely used and have proved safe and effective in treating moderate to severe Crohn's disease. However, contemporary bibliography contains little information about the use of these drugs in patients with end-stage renal disease undergoing hemodialysis. Here we present a case of a 47-year-old female patient with treatment-refractory Crohn's disease on hemodialysis. In this patient, treatment with the anti-IL-12/23 receptor antibody ustekinumab was effective in inducing and maintaining remission while being safe in administering throughout hemodialysis.

The Probiotic Strains Bifidοbacterium lactis, Lactobacillus acidophilus, Lactiplantibacillus plantarum and Saccharomyces boulardii Regulate Wound Healing and Chemokine Responses in Human Intestinal Subepithelial Myofibroblasts

Bifidobacterium lactis, Lactobacillus acidophilus, Lactiplantibacillus plantarum and Saccharomyces boulardii are common probiotic supplements. Colonic subepithelial myofibroblasts (cSEMFs) are actively involved in mucosal wound healing and inflammation. cSEMFs, isolated from healthy individuals, were stimulated with 102 or 104 cfu/mL of these probiotic strains alone and in combination, and their effect on chemokine and wound healing factor expression was assessed by qRT-PCR, ELISA and Sircol Assay, and on cSEMFs migration, by Wound Healing Assay. These strains remained viable and altered cSEMFs' inflammatory and wound healing behavior, depending on the strain and concentration. cSEMFs treated with a combination of the four probiotics had a moderate, but statistically significant, increase in the mRNA and/or protein expression of chemokines CXCL1, CXCL2, CXCL4, CXCL8, CXCL10, CCL2 and CCL5, and healing factors, collagen type I and III, fibronectin and tissue factor. In contrast, when each strain was administered alone, different effects were observed, with greater increase or decrease in chemokine and healing factor expression, which was balanced by the mixture. Overall, this study highlights that the use of multiple probiotic strains can potentially alert the gut mucosal immune system and promote wound healing, having a better effect on mucosal immunity than the use of single probiotics.

Amniotic Fluid-Derived Mesenchymal Stem/Stromal Cell-Derived Secretome and Exosomes Improve Inflammation in Human Intestinal Subepithelial Myofibroblasts.

Inflammatory Bowel Diseases (IBDs) are characterized by chronic relapsing inflammation of the gastrointestinal tract. The mesenchymal stem/stromal cell-derived secretome and secreted extracellular vesicles may offer novel therapeutic opportunities in patients with IBD. Thus, exosomes may be utilized as a novel cell-free approach for IBD therapy. The aim of our study was to examine the possible anti-inflammatory effects of secretome/exosomes on an IBD-relevant, in vitro model of LPS-induced inflammation in human intestinal SubEpithelial MyoFibroblasts (SEMFs). The tested CM (Conditioned Media)/exosomes derived from a specific population of second-trimester amniotic fluid mesenchymal stem/stromal cells, the spindle-shaped amniotic fluid MSCs (SS-AF-MSCs), and specifically, their secreted exosomes could be utilized as a novel cell-free approach for IBD therapy. Therefore, we studied the effect of SS-AF-MSCs CM and exosomes on LPS-induced inflammation in SEMF cells. SS-AF-MSCs CM and exosomes were collected, concentrated, and then delivered into the cell cultures. Administration of both secretome and exosomes derived from SS-AF-MSCs reduced the severity of LPS-induced inflammation. Specifically, IL-1ß, IL-6, TNF-α, and TLR-4 mRNA expression was decreased, while the anti-inflammatory IL-10 was elevated. Our results were also verified at the protein level, as secretion of IL-1ß was significantly reduced. Overall, our results highlight a cell-free and anti-inflammatory therapeutic agent for potential use in IBD therapy.

Biomarkers in Inflammatory Bowel Diseases: Predicting the Indication and the Effect of Biologics.

Crohn's disease and ulcerative colitis, the two most common inflammatory bowel diseases (IBD), are characterized by chronic relapsing inflammation. Although recent progress regarding the therapeutic approach to these diseases has been made in the development of biologic therapies, not every patient responds well, resulting in a high percentage of ineffectiveness. Even though the immunological cascades range between the current pharmacological agents for IBD treatment and the constant research for more possible pharmacological targets, a lot of progress still needs to be made regarding the correct therapeutical choice for each individual patient. Therefore, it is still important to find proper, inexpensive, and measurable biomarkers, in order to be able to assess the efficacy of these therapies, to make personalized choices, as well as to avoid potential adverse drug reactions and side effects. The biomarkers that are available in the present vary; metabolic, microbial, cytokine-related, genetic, disease-specific and drug-specific. This review presents the existing biological agents for IBD and focuses both on the cascades affected by each biologic agent and on the different markers that have been found to be indicative of their effectiveness.

Co-expression of fibrotic genes in inflammatory bowel disease; A localized event?

Introduction: Extracellular matrix turnover, a ubiquitous dynamic biological process, can be diverted to fibrosis. The latter can affect the intestine as a serious complication of Inflammatory Bowel Diseases (IBD) and is resistant to current pharmacological interventions. It embosses the need for out-of-the-box approaches to identify and target molecular mechanisms of fibrosis. Methods and results: In this study, a novel mRNA sequencing dataset of 22 pairs of intestinal biopsies from the terminal ileum (TI) and the sigmoid of 7 patients with Crohn's disease, 6 with ulcerative colitis and 9 control individuals (CI) served as a validation cohort of a core fibrotic transcriptomic signature (FIBSig), This signature, which was identified in publicly available data (839 samples from patients and healthy individuals) of 5 fibrotic disorders affecting different organs (GI tract, lung, skin, liver, kidney), encompasses 241 genes and the functional pathways which derive from their interactome. These genes were used in further bioinformatics co-expression analyses to elucidate the site-specific molecular background of intestinal fibrosis highlighting their involvement, particularly in the terminal ileum. We also confirmed different transcriptomic profiles of the sigmoid and terminal ileum in our validation cohort. Combining the results of these analyses we highlight 21 core hub genes within a larger single co-expression module, highly enriched in the terminal ileum of CD patients. Further pathway analysis revealed known and novel inflammation-regulated, fibrogenic pathways operating in the TI, such as IL-13 signaling and pyroptosis, respectively. Discussion: These findings provide a rationale for the increased incidence of fibrosis at the terminal ileum of CD patients and highlight operating pathways in intestinal fibrosis for future evaluation with mechanistic and translational studies.

Elevated Levels of Alveolar Nitric Oxide May Indicate Presence of Small Airway Inflammation in Patients with Inflammatory Bowel Disease.

INTRODUCTION: Pulmonary manifestations of inflammatory bowel disease (IBD), albeit not rare, are largely overlooked in clinical practice. The role of exhaled nitric oxide (eNO) as an established biological marker of airway inflammation compels us to use it as a tool to investigate the exact nature of these manifestations. METHODS: Fractional eNO (FeNO) was measured in multiple flows, and with the use of a mathematical model, alveolar concentration of NO (CANO) and bronchial flux of NO (JawNO) were assessed in 27 patients with IBD [17 with Crohn's disease (CD) and 10 with ulcerative colitis (UC)] and in 39 healthy controls. Carefully selected criteria were used to exclude patients or healthy controls that presented factors considered to be correlated with eNO measurements. Disease activity was measured in Crohn's patients using the CD activity index (CDAI) score and in UC using the partial Mayo score. RESULTS: CANO was significantly higher in the IBD group, compared to the control group (p < 0.0001). FeNO was significantly increased in patients with IBD (p = 0.023), while there was no statistical significance found regarding levels of JawNO in patients with IBD (p = 0.106), both compared to controls. There was no significant correlation between any eNO component and markers of disease activity. CONCLUSIONS: Alveolar concentration of NO is elevated in patients with IBD, regardless of disease activity. This may suggest that subclinical small airway inflammation is present in patients with IBD, even those with mild or inactive disease.

Cytokine Receptor Profiling in Human Colonic Subepithelial Myofibroblasts: A Differential Effect of Th Polarization-Associated Cytokines in Intestinal Fibrosis.

Background: Colonic subepithelial myofibroblasts (cSEMFs) are mesenchymal cells with a pivotal role in the pathophysiology of Crohn's disease (CD) fibrosis. Here, we demonstrate for the first time a complete expression mapping of cytokine receptors, implicated in inflammatory bowel diseases, in primary human cSEMFs and how pro-inflammatory cytokines regulate this expression. Furthermore, we show the effect of Th1-, Th2-, Th17- and Treg-related cytokines on a fibrosis-related phenotype of cSEMFs. Methods: Colonic subepithelial myofibroblasts were isolated from healthy individuals' colonic biopsies. Interleukin (IL)-1α- and/or tumor necrosis factor (TNF)-α-induced mRNA and protein expression of cytokine receptors was assayed by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and immunofluorescence, respectively. Th-related cytokine effects on mRNA and protein profibrotic factor expression were analyzed by qRT-PCR and/or colorimetric assays and on the wound-healing capacity of cSEMFs by scratch test. Results: In cSEMFs, we observed basal cytokine receptor expression, which was modified by IL-1α and TNF-α. Th1-related cytokines upregulated tissue factor (TF), collagen, fibronectin and matrix metalloproteinase (MMP)-1 and downregulated α-smooth muscle actin (α-SMA), MMP-9, and wound healing rate. Th2-related cytokines upregulated collagen, TF, α-SMA, MMP-1, and wound healing rate and downregulated fibronectin and MMP-9. IL-17 and IL-23 upregulated fibronectin, and IL-22 downregulated TF. IL-17 and IL-22 decreased wound healing rate. Similar to TGF-ß, IL-23 upregulated MMP-1, tissue inhibitor of metalloproteinases-1, collagen expression, and wound healing rates. Conclusions: Our results suggest that cSEMFs have a central role in inflammation and fibrosis, as they express a great variety of Th-related cytokine receptors, making them responsive to pro-inflammatory cytokines, abundant in the inflamed mucosa of CD patients.

Endoscopically Assisted Transumbilical Single-Incision Laparoscopic Gastric Resection for GIST Treatment.

PURPOSE: Complete surgical resection with negative margins without lymphadenectomy is the treatment of choice for nonmetastatic Gastrointestinal Stromal Tumors (GISTs). Laparoscopic resection of gastric GISTs <5 cm is an acceptable and oncologically feasible, safe, and effective treatment. We present our experience of an endoscopically assisted minimally invasive transumbilical single-incision laparoscopic (SILS) technique for gastric GISTs resection. METHODS: Four patients with small gastric GISTs ≤5 cm located on the greater curvature or the anterior wall were resected with SILS by using a lesion-lifting technique under the guidance of flexible gastroscopy. RESULTS: The technique was feasible and safe and offered significant advantages in locating the tumor and controlling the resection margins. There were no major intraoperative or postoperative complications, conversions, or tumor ruptures. Pathology showed low-risk GISTs resected with disease-free margins without tumor rupture. No recurrences have been observed. CONCLUSION: The endoscopically assisted SILS wedge gastrectomy is a feasible, safe, and advantageous technique for the treatment of the greater curvature or anterior wall gastric GISTs.

Patients with established gastro-esophageal reflux disease might benefit from Helicobacter pylori eradication.

BACKGROUND: The aim of this study was to investigate the effect of Helicobacter pylori (H. pylori) eradication in selected H. pylori-positive patients with a primary diagnosis of gastro-esophageal reflux disease (GERD) by using the 3-h postprandial esophageal pH monitoring. METHODS: We recruited patients with erosive esophagitis at endoscopy and H. pylori infection at histology, successfully cured following eradication therapy; the selected H. pylori-positive patients had weekly reflux symptoms for at least six months and endoscopically established Grade A or B esophagitis. Twenty-nine eligible patients were initially subjected to esophageal manometry and ambulatory 3-h postprandial esophageal pH monitoring. All patients received H. pylori triple eradication therapy accompanied by successful H. pylori eradication. After successful eradication of H. pylori (confirmed by 13C urea breath test), a second manometry and 3-h postprandial esophageal pH monitoring were introduced to assess the results of eradication therapy, after a 3-month post-treatment period. RESULTS: All 29 selected H. pylori-positive patients became negative due to successful H. pylori eradication, evaluated by 13C urea breath test after a 4-week post-treatment period. Post-eradication, 62.1% patients showed similar manometric pattern at baseline; 17.2% showed improvement; 17.2% normalization; and 3.4% deterioration of the manometric patterns. The DeMeester symptom scoring in the 3-h postprandial ambulatory esophageal pH monitoring was improved after eradication of H. pylori (median 47.47 vs. 22.00, Wilcoxon's singed rank; P=0.016). On comparing the pH monitoring studies for each patient at baseline and post-eradication period, 82.8% patients showed improvement and 17.2% deterioration of the DeMeester score. CONCLUSION: By using 3-h postprandial esophageal pH monitoring, this study showed, for the first time, that H. pylori eradication may positively influence GERD symptoms. Large-scale controlled relative studies are warranted to confirm these findings.

Chromogranin A as a biomarker of disease activity and biologic therapy in inflammatory bowel disease: a prospective observational study.

OBJECTIVE: To access the correlation of Chromogranin A (CgA) with inflammatory bowel disease (IBD) activity and responsiveness to medical therapy. MATERIAL AND METHODS: A prospective observational study was conducted in 56 patients with moderate ulcerative colitis (UC) or Crohn's disease (CD) (UC, n = 29, CD, n = 27), 17 patients with irritable bowel syndrome and predominant diarrhea (IBS-D) and 40 healthy volunteers. IBD patients were treated by biologics (infliximab or adalimumab) or conventional agents (aminosalicylates, thiopurines or methotrexate and steroids) and were classified according to their treatment in two groups. Serum CgA was measured at baseline and 4-week posttreatment period. RESULTS: Serum CgA was significantly higher in IBD patients than in those with IBS-D or healthy volunteers (p < 0.01). Furthermore, serum CgA was markedly increased in CD patients than in UC patients (p < 0.01). CgA value was significantly reduced in 'biologic' group (24 IBD patients, UC, n = 15, CD, n = 9) at 4-week posttreatment period (p < 0.01), while 18/24 (72%) patients were already in remission during that time. In contrast, CgA value was significantly increased in the 'conventional' treatment group (32 IBD patients, UC, n = 14, CD, n = 18) between the two visits (p < 0.01), although 22/32 (69%) patients were in remission during the 4-week posttreatment period. CONCLUSION: CgA appears to be a reliable marker of disease activity in IBD patients and especially in those who received biologic therapy. IBS-D patients presented normal CgA values.

Tissue factor-thrombin signaling enhances the fibrotic activity of myofibroblasts in systemic sclerosis through up-regulation of endothelin receptor A.

OBJECTIVE: The extrinsic coagulation cascade is involved in the fibrotic process, via thrombin-dependent induction of CCN2 (connective tissue growth factor) expression. Given the previously reported activation of the coagulation system in systemic sclerosis (SSc), we undertook the present study to investigate the involvement of cross-talk between the tissue factor (TF)-thrombin axis and endothelin 1 (ET-1) signaling in the fibrotic activity of SSc. METHODS: Human colonic myofibroblasts (HCMFs) from 6 patients with SSc and gastrointestinal symptoms and from 6 control subjects were isolated and cultured under various conditions. Messenger RNA and protein levels of TF, CCN2, and endothelin receptor A (ET(A) ) were investigated. Collagen production and migratory activity of HCMFs were further assessed. RESULTS: HCMFs from SSc patients demonstrated increased basal CCN2 production, collagen deposition, and migration rate, in a thrombin-dependent manner. Increased TF expression was also observed in SSc HCMFs. Subsequent activation of the extrinsic coagulation system resulted in thrombin-dependent enhancement of ET(A) expression. ET(A) overexpression led to further increases in both TF expression and fibrotic activity in HCMFs. Moreover, inhibition of ET-1 signaling by bosentan abolished the TF-mediated fibrotic capacity of HCMFs. CONCLUSION: Tissue factor-thrombin signaling is involved in the increased fibrotic activity of HCMFs from patients with SSc. Moreover, the up-regulation of ET(A) expression by thrombin and the effect of ET-1 in the induction of TF expression indicate an amplification loop for enhanced collagen deposition. Therapeutic interventions targeting the extrinsic coagulation system or ET-1 signaling may provide clinical benefit by breaking this vicious circle.

Primary hepatic gastrinoma: Report of a case and review of literature.

Primary hepatic gastrinoma is a very rare ectopic gastrinoma with less than 20 cases reported worldwide. We report the case of a patient with hypergastrinemia who was subjected to exhaustive preoperative and intraoperative imaging and also careful surgical exploration of the duodenum and pancreas which failed initially to identify the primary tumour. Eventually the patient was subjected to left liver lobectomy, as a small palpable lesion was noted intraoperatively. The diagnosis of gastrinoma requires a high index of clinical suspicion and the flawless cooperation of many specialties.

Endothelin-1 signaling promotes fibrosis in vitro in a bronchopulmonary dysplasia model by activating the extrinsic coagulation cascade.

Neonatal respiratory distress syndrome can progress to bronchopulmonary dysplasia (BPD), a serious pulmonary fibrotic disorder. Given the involvement of the extrinsic coagulation cascade in animal models of lung fibrosis, we examined its role in BPD. We observed a higher number of neutrophils expressing tissue factor (TF) in bronchoalveolar lavage fluid (BALF) from infants with BPD than from those with uncomplicated respiratory distress syndrome together with a parallel decrease in TF and connective tissue growth factor (CTGF) in BALF supernatants during the disease course. The involvement of coagulation in the fibrotic process associated with BPD was further evaluated by treating primary human colonic myofibroblasts with BALF supernatants from infants with BPD. These human colonic myofibroblasts demonstrated an enhanced C5a- and thrombin-dependent migration. Moreover, they expressed TF in an endothelin-1-dependent manner, with subsequent activation of the extrinsic coagulation cascade and CTGF production mediated by protease-activator receptor-1 signaling. These data provide a novel mechanism for the development of BPD and indicate that endothelin-1 signaling contributes to fibrosis by upregulating a TF/thrombin amplification loop responsible for CTGF production, and offer novel and specific therapeutic targets for pulmonary fibrotic disease.