Shinya Munakata

Inhibition of plasmin attenuates murine acute graft-versus-host disease mortality by suppressing the matrix metalloproteinase-9-dependent inflammatory cytokine storm and effector cell trafficking

The systemic inflammatory response observed during acute graft-versus-host disease (aGVHD) is driven by proinflammatory cytokines, a ‘cytokine storm’. The function of plasmin in regulating the inflammatory response is not fully understood, and its role in the development of aGVHD remains unresolved. Here we show that plasmin is activated during the early phase of aGVHD in mice, and its activation correlated with aGVHD severity in humans. Pharmacological plasmin inhibition protected against aGVHD-associated lethality in mice. Mechanistically, plasmin inhibition impaired the infiltration of inflammatory cells, the release of membrane-associated proinflammatory cytokines including tumor necrosis factor-α (TNF-α) and Fas-ligand directly, or indirectly via matrix metalloproteinases (MMPs) and alters monocyte chemoattractant protein-1 (MCP-1) signaling. We propose that plasmin and potentially MMP-9 inhibition offers a novel therapeutic strategy to control the deadly cytokine storm in patients with aGVHD, thereby preventing tissue destruction.

Fibrinolytic crosstalk with endothelial cells expands murine mesenchymal stromal cells

Tissue plasminogen activator (tPA), aside from its vascular fibrinolytic action, exerts various effects within the body, ranging from synaptic plasticity to control of cell fate. Here, we observed that by activating plasminogen and matrix metalloproteinase-9, tPA expands murine bone marrow-derived CD45(-)TER119(-)Sca-1(+)PDGFRα(+) mesenchymal stromal cells (PαS-MSCs) in vivo through a crosstalk between PαS-MSCs and endothelial cells. Mechanistically, tPA induces the release of Kit ligand from PαS-MSCs, which activates c-Kit(+) endothelial cells to secrete MSC growth factors: platelet-derived growth factor-BB (PDGF-BB) and fibroblast growth factor 2 (FGF2). In synergy, FGF2 and PDGF-BB upregulate PDGFRα expression in PαS-MSCs, which ultimately leads to PαS-MSC expansion. These data show a novel mechanism by which the fibrinolytic system expands PαS-MSCs through a cytokine crosstalk between niche cells.

Plasminogen activator inhibitor-1 regulates macrophage-dependent postoperative adhesion by enhancing EGF-HER1 signaling in mice

Adhesive small bowel obstruction remains a common problem for surgeons. After surgery, platelet aggregation contributes to coagulation cascade and fibrin clot formation. With clotting, fibrin degradation is simultaneously enhanced, driven by tissue plasminogen activator–mediated cleavage of plasminogen to form plasmin. The aim of this study was to investigate the cellular events and proteolytic responses that surround plasminogen activator inhibitor (PAI‐1; Serpine1) inhibition of postoperative adhesion. Peritoneal adhesion was induced by gauze deposition in the abdominal cavity in C57BL/6 mice and those that were deficient in fibrinolytic factors, such as Plat−/− and Serpine1−/−. In addition, C57BL/6 mice were treated with the novel PAI‐1 inhibitor, TM5275. Some animals were treated with clodronate to deplete macrophages. Epidermal growth factor (EGF) experiments were performed to understand the role of macrophages and how EGF contributes to adhesion. In the early phase of adhesive small bowel obstruction, increased PAI‐1 activity was observed in the peritoneal cavity. Genetic and pharmacologic PAI‐1 inhibition prevented progression of adhesion and increased circulating plasmin. Whereas Serpine1−/− mice showed intra‐abdominal bleeding, mice that were treated with TM5275 did not. Mechanistically, PAI‐1, in combination with tissue plasminogen activator, served as a chemoattractant for macrophages that, in turn, secreted EGF and up‐regulated the receptor, HER1, on peritoneal mesothelial cells, which led to PAI‐1 secretion, further fueling the vicious cycle of impaired fibrinolysis at the adhesive site. Controlled inhibition of PAI‐1 not only enhanced activation of the fibrinolytic system, but also prevented recruitment of EGF‐secreting macrophages. Pharmacologic PAI‐1 inhibition ameliorated adhesion formation in a macrophage‐dependent manner.—Honjo, K., Munakata, S., Tashiro, Y., Salama, Y., Shimazu, H., Eiamboonsert, S., Dhahri, D., Ichimura, A., Dan, T., Miyata, T., Takeda, K., Sakamoto, K., Hattori, K., Heissig, B. Plasminogen activator inhibitor‐1 regulates macrophage‐dependent postoperative adhesion by enhancing EGF‐HER1 signaling in mice. FASEB J. 31, 2625–2637 (2017). www.fasebj.org

Clinical pathway to discharge 3 days after colorectal endoscopic submucosal dissection

Colorectal endoscopic submucosal dissection (ESD) is a useful treatment method; however, no index has been established for time for patient to start food ingestion or be discharged after ESD. We investigated the potential of a clinical pathway in which patients started food ingestion on day 2 after ESD and were discharged on day 3.

Pharmacological targeting of plasmin prevents lethality in a murine model of macrophage activation syndrome

Macrophage activation syndrome (MAS) is a life-threatening disorder characterized by a cytokine storm and multiorgan dysfunction due to excessive immune activation. Although abnormalities of coagulation and fibrinolysis are major components of MAS, the role of the fibrinolytic system and its key player, plasmin, in the development of MAS remains to be solved. We established a murine model of fulminant MAS by repeated injections of Toll-like receptor-9 (TLR-9) agonist and d-galactosamine (DG) in immunocompetent mice. We found plasmin was excessively activated during the progression of fulminant MAS in mice. Genetic and pharmacological inhibition of plasmin counteracted MAS-associated lethality and other related symptoms. We show that plasmin regulates the influx of inflammatory cells and the production of inflammatory cytokines/chemokines. Collectively, our findings identify plasmin as a decisive checkpoint in the inflammatory response during MAS and a potential novel therapeutic target for MAS.

Cancer therapy targeting the fibrinolytic system

The tumor microenvironment is recognized as a key factor in the multiple stages of cancer progression, mediating local resistance, immune-escape and metastasis. Cancer growth and progression require remodeling of the tumor stromal microenvironment, such as the development of tumor-associated blood vessels, recruitment of bone marrow-derived cells and cytokine processing. Extracellular matrix breakdown achieved by proteases like the fibrinolytic factor plasmin and matrix metalloproteases is necessary for cell migration crucial for cancer invasion and metastasis. Key components of the fibrinolytic system are expressed in cells of the tumor microenvironment. Plasmin can control growth factor bioavailability, or the regulation of other proteases leading to angiogenesis, and inflammation. In this review, we will focus on the role of the fibrinolytic system in the tumor microenvironment summarizing our current understanding of the role of the fibrinolytic factors for the modulation of the local chemokine/cytokine milieu, resulting in myeloid cell recruitment, which can promote neoangiogenesis.

Impact of chromosome 17q deletion in the primary lesion of colorectal cancer on liver metastasis

Colorectal cancer is a prevalent malignancy worldwide, and investigations are required to elucidate the underlying carcinogenic mechanisms. Amongst these mechanisms, de novo carcinogenesis and the adenoma to carcinoma sequence, are the most understood. Metastasis of colorectal cancer to the liver often results in fatality, therefore, it is important for any associated risk factors to be identified. Regarding the treatment of the disease, it is important to manage not only the primary colorectal tumor, but also the liver metastases. Previously, through gene variation analysis, chromosomal loss has been indicated to serve an important role in liver metastasis. Such analysis may aid in the prediction of liver metastasis risk, alongside individual responses to treatment, thus improving the management of colorectal cancer. In the present study, we aimed to clarify a cause of the liver metastasis of colorectal cancer using comparative genomic hybridization analysis. A total of 116 frozen samples were analyzed from patients with advanced colorectal cancer that underwent surgery from 2004 to 2011. The present study analyzed mutations within tumor suppressor genes non-metastatic gene 23 (NM23), deleted in colorectal carcinoma (DCC) and deleted in pancreatic carcinoma, locus 4 (DPC4), which are located on chromosomes 17 and 18 and have all been reported to affect liver metastasis of colorectal cancer. The association between chromosomal abnormalities (duplication and deletion) and liver metastasis of colorectal cancer was evaluated using comparative genomic hybridization. Cluster analysis indicated that the group of patients lacking the long arm of chromosome 17 demonstrated the highest rate of liver metastasis. No significant association was observed between the frequency of liver metastases for synchronous and heterochronous colorectal cancer cases and gene variation (P=0.206). However, when these liver metastasis cases were divided into the synchronous and heterochronous types, the ratio of each was significantly different between gene variation groups, classified by the existence of the 17q deletion (P=0.023). These results indicate that the deletion of 17q may act as a predictive marker of liver metastasis in postoperative states.

Successful Retrieval of a Retained Capsule Endoscope with Single Incision Laparoscopic Surgery

Capsule endoscopy (CE) is commonly used for examining and diagnosing gastrointestinal disease, especially small bowel disease. Capsule retention is a well-known and significant complication of CE and requires surgical or endoscopic removal. Most reports described the retrieval of retained CE via laparotomy. We report a case of successful retrieval of the capsule using single incision laparoscopic surgery.

T1 colorectal cancer with synchronous liver metastasis.

The patient was a 68-year-old man who was admitted to our hospital with a liver tumor. Abdominal ultrasonography and computed tomography revealed a liver tumor 30 mm in diameter. On colonoscopy, a pedunculated tumor with a central depression (20 mm in diameter) was observed in the ascending colon, and this tumor was considered to be invading deeply into the submucosal layer. Right hemicolectomy with D3 lymphadenectomy and partial hepatectomy were performed simultaneously. On histopathological examination of the resected specimen, the tumor was a well-differentiated tubular adenocarcinoma with 3,000 μm invasion of the submucosal layer. The liver tumor showed histological findings similar to those of the primary colorectal carcinoma. The pathological stage according to the 7th edition of the TNM classification was stage IV (T1N0M1). Nine months after the operation, computed tomography revealed hepatic hilar lymph node metastases and a great deal of ascites. The patient ultimately died 14 months after the operation.

Impact of Chylous Ascites on Colon Cancer in Laparoscopic Surgery

Objectives: To investigate the epidemiology and risk factors of chylous ascites. Methods: We identified the cases of 913 consecutive patients who underwenturgery for colorectal cancerat our University Hospital between January 2005and December2016. We divided the patients into thosewith and those without chylous ascites and compared the two groups by age, gender, body mass index, tumor location, T, N factor, stage, operation time, intra-operative bleeding, and duration of postoperative hospital stay. Results: Chylous ascites developed in 8 of the 913 patients (0.8%). Neither age, sex, tumor location, and body mass indexnor number of lymph nodeswereassociated with postoperative chylous ascites. Ascites occurred significantly less frequently in the early stage of colorectal cancer than in the late stage (p = 0.04). There was no significant difference between the groups in operative factors, including operation time and blood loss. Postoperative hospital stays were longer in patients with chylous ascites (20.5 days) than in those without (11 days) (p = 0.02). Conclusions: Late stage was one of the risk factors for chylous ascites in the present study. Other risks, such as tumor location and blood loss,will vary from institution to institution.