Keitaro Tashiro

Chymase inhibition attenuates tetrachloride-induced liver fibrosis in hamsters

Aim:  Chymase converts angiotensin I to angiotensin II, which may promote the development of liver fibrosis. In this study, whether a chymase inhibitor TY‐51469 attenuated tetrachloride (CCl4)‐induced liver fibrosis was examined.

Chymase inhibitor prevents the nonalcoholic steatohepatitis in hamsters fed a methionine- and choline-deficient diet.

Aim:  Mast cells may be involved in the pathogenesis of nonalcoholic steatohepatitis (NASH). The mast cell protease chymase contributes to the formation of angiotensin II and matrix metalloproteinase (MMP)‐9, both of which are intimately involved in liver fibrosis. Therefore, we hypothesized that chymase plays an important role in the development of NASH.

Laparoscopic gastrointestinal anastomoses using knotless barbed absorbable sutures are safe and reproducible: a single-center experience with 242 patients

OBJECTIVE Intracorporeal reconstruction of the digestive tract is technically challenging. The V-Loc 180 wound closure device (Covidien) is a self-anchoring unidirectional barbed suture that obviates the need for knot tying. The aim of this prospective cohort study was to investigate the use of the novel suture in gastrointestinal enterotomy closure. METHODS The subjects comprised patients with malignant disease who were scheduled to undergo laparoscopic gastrectomy with curative intent. The barbed suture was used to close the entry hole for the linear stapler during intracorporeal reconstruction following laparoscopic gastric resection. The primary endpoint was the proportion of patients who developed anastomotic leakage at the site where the barbed suture was applied. RESULTS Between July 2012 and March 2015, 242 patients were enrolled. Of 362 anastomoses, the enterotomy hole at 256 sites was closed using the barbed suture. These 256 sites consisted of 95 gastroduodenostomies, 25 gastrogastrostomies, 13 gastrojejunostomies, 90 jejunojejunostomies, 17 esophagojejunostomies and 16 primary closures of the stomach following local gastric resection. There were no anastomosis-related complications, conversion to usual sutures, mechanical closure of the entry hole and reoperation due to adhesive obstructions or mortality over a median follow-up period of 17.8 months. CONCLUSIONS The use of the unidirectional barbed absorbable suture for gastrointestinal closure is safe and effective in laparoscopic gastrectomy.

Chymase inhibitor ameliorates hepatic steatosis and fibrosis on established non-alcoholic steatohepatitis in hamsters fed a methionine- and choline-deficient diet

Chymase plays a role in the augmentation of angiotensin II formation, which is involved in liver fibrosis. The therapeutic effects of a chymase inhibitor, TY‐51469, on established hepatic steatosis and fibrosis were investigated in a model of developed non‐alcoholic steatohepatitis.

Chymase Inhibition Attenuates Lipopolysaccharide/ D-Galactosamine-Induced Acute Liver Failure in Hamsters

Background/Aims: Chymase inhibition has been shown to attenuate matrix metalloproteinase (MMP)-9 and tumor necrosis factor (TNF)-α, both of which are associated with the pathogenesis of acute liver failure (ALF). This study investigated the effects of the chymase inhibitor TY-51469 on lipopolysaccharide (LPS)/D-galactosamine (GalN)-induced ALF in hamsters. Methods: TY-51469 (10 or 30 mg/kg) or placebo was administered 1 h before the LPS (160 µg/kg)/GalN (400 mg/kg) injection. Results: Hepatic chymase activity was significantly increased after the LPS/GalN injection, but the significant increase was dose-dependently and significantly attenuated by treatment with TY-51469. Significant increases in hepatic MMP-9 activity and TNF-α concentration were observed after the LPS/GalN injection, but these increases were also attenuated by treatment with TY-51469. Plasma aspartate aminotransferase and alanine aminotransferase activities were significantly increased after LPS/GalN injection in the placebo-treated group, but the increases were significantly attenuated in the TY-51469-treated group. The area of hepatic necrotic after LPS/GalN injection was significantly reduced by treatment with TY-51469. Treatment with TY-51469 resulted in significant reductions in the hepatic malondialdehyde concentration, mast cell numbers, and gene expressions of interleukin-1β and myeloperoxidase. Discussion: Chymase inhibition could be a useful strategy to attenuate LPS/GalN-induced ALF in hamsters.

Chymase Inhibition Attenuates Monocrotaline-Induced Sinusoidal Obstruction Syndrome in Hamsters

Chymase stored in mast cells activates matrix metalloproteinase (MMP)-9, which may relate to the progression of sinusoidal obstruction syndrome (SOS). We investigated the preventive effect of a chymase inhibitor, TY-51469, on monocrotaline-induced SOS in hamsters. Hamsters were orally administrated with a single dose of monocrotaline (120 mg/kg) to induce SOS. Treatment with TY-51469 (1 mg/kg per day) or placebo had started 3 days before the monocrotaline administration. Two days after the monocrotaline administration, significant increases in aspartate aminotransferase, alanine aminotransferase and total bilirubin and a significant reduction of albumin were observed in plasma, but their changes were significantly attenuated by treatment with TY-51469. The numerous hepatic necrosis areas were observed in the placebo-treated group, but the ratio of necrotic area to total area in liver had been significantly reduced by treatment with TY-51469. Both chymase activity and MMP-9 level in liver were significantly augmented in the placebo-treated group. Furthermore, tumor necrosis factor (TNF)-α level in liver was also augmented in the placebo-treated group. However, the chymase activity and levels of MMP-9 and TNF-α were significantly attenuated in the TY-51469-treated group. Until 14 days after monocrotaline administration, survival rates in the placebo- and TY-51469-treated groups were 25% and 70%, respectively, and a significant difference was observed. In conclusion, chymase inhibition by TY-51469 may prevent the accelerating of severity in monocrotaline-induced SOS in hamsters.

Preoperative Chemotherapy May Not Influence the Remnant Liver Regenerations and Outcomes After Hepatectomy for Colorectal Liver Metastasis

BackgroundVarious chemotherapy regimens have been shown to improve outcomes when administered before tumor excision surgery. However, there is no consensus on the utility of multidisciplinary treatment with preoperative chemotherapy for treating colorectal liver metastasis (CLM).Materials and methodsTwo hundred-fifty patients who underwent hepatectomy were retrospectively analyzed using propensity score matching. Postoperative outcomes were evaluated with a focus on the effect of pre-hepatectomy chemotherapy on regeneration of the remnant liver in patients with CLM. The remnant liver volumes (RLVs) were postoperatively measured with multidetector computed tomography on days 7 and months 1, 2, 5, and 12 after the operation.ResultsRLV regeneration and blood test results did not significantly differ between patients who underwent preoperative chemotherapy versus those who did not immediately after surgery or at any time point from postoperative day 7 to postoperative month 12. The 1-, 2-, and 3-year overall survival (OS) rates for all patients were 94.6, 86.2, and 79.9%, respectively; the corresponding disease-free survival (RFS) rates were 49.3, 38.6, and 33.7%, respectively. There were no significant differences in OS and RFS between the two groups after hepatic resection. The recurrence rates, including marginal and intrahepatic recurrences, as well as resection frequency of the remnant liver were not significantly different between the two groups.ConclusionPreoperative chemotherapy may have no appreciable benefit for patients with CLM in terms of perioperative and long-term outcomes.

A novel hamster nonalcoholic steatohepatitis model induced by a high-fat and high-cholesterol diet

Nonalcoholic steatohepatitis (NASH), in which there is steatosis and fibrosis in the liver, is linked to metabolic syndrome and progresses to hepatic cirrhosis. In this study, a novel hamster NASH model derived from metabolic syndrome was made using hamsters. Hamsters were fed a normal or a high-fat and high-cholesterol (HFC) diet for 12 weeks. Body weight and the ratio of liver weight to body weight were significantly greater in HFC diet-fed hamsters than in normal diet-fed hamsters. Triglyceride, low-density lipoprotein cholesterol, and glucose levels in blood were significantly increased in HFC diet-fed hamsters, and blood pressure also tended to be high, suggesting that the HFC diet-fed hamsters developed metabolic syndrome. Hepatic steatosis and fibrosis were observed in liver sections of HFC diet-fed hamsters, as in patients with NASH, but they were not seen in normal diet-fed hamsters. Chymase generates angiotensin II and transforming growth factor (TGF)-β, both of which are related to hepatic steatosis and fibrosis, and a significant augmentation of chymase activity was observed in livers from HFC diet-fed hamsters. Both angiotensin II and TGF-β were also significantly increased in livers of HFC diet-fed hamsters. Thus, HFC diet-fed hamsters might develop metabolic syndrome-derived NASH that clinically resembles that in NASH patients.

Nogo-B (Reticulon-4B) functions as a negative regulator of the apoptotic pathway through the interaction with c-FLIP in colorectal cancer cells

Nogo-B is a member of the Nogo/Reticulon-4 family and has been reported to be an inducer of apoptosis in certain types of cancer cells. However, the role of Nogo-B in human cancer remains less understood. Here, we demonstrated the functions of Nogo-B in colorectal cancer cells. In clinical colorectal cancer specimens, Nogo-B was obviously overexpressed, as determined by immunohistochemistry; and Western blot analysis showed its expression level to be significantly up-regulated. Furthermore, knockdown of Nogo-B in two colorectal cancer cell lines, SW480 and DLD-1, by transfection with si-RNA (siR) resulted in significantly reduced cell viability and a dramatic increase in apoptosis with insistent overexpression of cleaved caspase-8 and cleaved PARP. The transfection with Nogo-B plasmid cancelled that apoptosis induced by siRNogoB in SW480 cells. Besides, combinatory treatment with siR-Nogo-B/staurosporine (STS) or siR-Nogo-B/Fas ligand (FasL) synergistically reduced cell viability and increased the expression of apoptotic signaling proteins in colorectal cancer cells. These results strongly support our contention that Nogo-B most likely played an oncogenic role in colorectal cancer cells, mainly by negatively regulating the extrinsic apoptotic pathway in them. Finally, we revealed that suppression of Nogo-B caused down-regulation of c-FLIP, known as a major anti-apoptotic protein, and activation of caspase-8 in the death receptor pathway. Interaction between Nogo-B and c-FLIP was shown by immunoprecipitation and immunofluorescence studies. In conclusion, Nogo-B was shown to play an important negative role in apoptotic signaling through its interaction with c-FLIP in colorectal cancer cells, and may thus become a novel therapeutic target for colorectal cancer.