Serous Membrane Detachment with Ultrasonic Homogenizer Improves Engraftment of Fetal Liver to Liver Surface in a Rat Model of Cirrhosis.

Liver transplantation is the most effective treatment for end-stage cirrhosis. However, due to serious donor shortages, new treatments to replace liver transplantation are sorely needed. Recent studies have focused on novel therapeutic methods using hepatocytes and induced pluripotent stem cells, we try hard to develop methods for transplanting these cells to the liver surface. In the present study, we evaluated several methods for their efficiency in the detachment of serous membrane covering the liver surface for transplantation to the liver surface. The liver surface of dipeptidyl peptidase IV (DPPIV)-deficient rats in a cirrhosis model was detached by various methods, and then fetal livers from DPPIV-positive rats were transplanted. We found that the engraftment rate and area as well as the liver function were improved in rats undergoing transplantation following serous membrane detachment with an ultrasonic homogenizer, which mimics the Cavitron Ultrasonic Surgical Aspirator® (CUSA), compared with no detachment. Furthermore, the bleeding amount was lower with the ultrasonic homogenizer method than with the needle and electric scalpel methods. These findings provide evidence that transplantation to the liver surface with serous membrane detachment using CUSA might contribute to the development of new treatments for cirrhosis using cells or tissues.

Development of a Method for Scaffold-Free Elastic Cartilage Creation.

Microtia is a congenital aplasia of the auricular cartilage. Conventionally, autologous costal cartilage grafts are collected and shaped for transplantation. However, in this method, excessive invasion occurs due to limitations in the costal cartilage collection. Due to deformation over time after transplantation of the shaped graft, problems with long-term morphological maintenance exist. Additionally, the lack of elasticity with costal cartilage grafts is worth mentioning, as costal cartilage is a type of hyaline cartilage. Medical plastic materials have been transplanted as alternatives to costal cartilage, but transplant rejection and deformation over time are inevitable. It is imperative to create tissues for transplantation using cells of biological origin. Hence, cartilage tissues were developed using a biodegradable scaffold material. However, such materials suffer from transplant rejection and biodegradation, causing the transplanted cartilage tissue to deform due to a lack of elasticity. To address this problem, we established a method for creating elastic cartilage tissue for transplantation with autologous cells without using scaffold materials. Chondrocyte progenitor cells were collected from perichondrial tissue of the ear cartilage. By using a multilayer culture and a three-dimensional rotating suspension culture vessel system, we succeeded in creating scaffold-free elastic cartilage from cartilage progenitor cells.

The Regenerative Effect of Portal Vein Injection of Liver Organoids by Retrorsine/Partial Hepatectomy in Rats.

In this study, we reveal that liver organoid transplantation through the portal vein is a safe and effective method for the treatment of chronic liver damage. The liver organoids significantly reconstituted the hepatocytes; hence, the liver was significantly enlarged in this group, compared to the monolayer cell transplantation group in the retrorsine/partial hepatectomy (RS/PH) model. In the liver organoid transplantation group, the bile ducts were located in the donor area and connected to the recipient bile ducts. Thus, the rate of bile reconstruction in the liver was significantly higher compared to that in the monolayer group. By transplanting liver organoids, we saw a level of 70% replacement of the damaged liver. Consequently, in the transplantation group, diminished ductular reaction and a decrease of placental glutathione S-transferase (GST-p) precancerous lesions were observed. After trans-portal injection, the human induced pluripotent stem cell (hiPSC)-derived liver organoids revealed no translocation outside the liver; in contrast, the monolayer cells had spread to the lungs. The hiPSC-derived liver organoids were attached to the liver in the immunodeficient RS/PH rats. This study clearly demonstrates that liver organoid transplantation through the portal vein is a safe and effective method for the treatment of chronic liver damage in rats.

Lnc RNA H19 is associated with poor prognosis in breast cancer patients and promotes cancer stemness.

PURPOSE: Aldehyde dehydrogenase1 (ALDH1) is widely accepted as a stem cell marker for normal breast as well as in breast cancer. Although the clinical impact of ALDH1 was observed in our previous study, we do not know how ALDH1 affects stem cell features resulting in worsening of prognosis in breast cancer. The purpose of this study is to explore ALDH1-related gene and its function on cancer stem cell (CSC). METHODS: In five cases of ALDH1-positive triple-negative breast cancer, mRNA expression profile was compared between ALDH1-positive and ALDH1-negative cells by Affymetrix microarray analysis after microdissection. Among the genes modulated in ALDH1-positive cells, we focused on H19, which encodes a long non-coding RNA, in this study. An in-vitro study was conducted with H19 siRNA in HCC1934 and iCSCL10A cell lines. The association of H19 with prognosis was examined in 180 breast cancer cases. RESULTS: Network analysis revealed the existence of five genes related with H19, including miR-103, miR-107, let-7, miR-29b-1, and Trx. In-vitro analysis showed that suppression of H19 using siRNA reduces sphere formation capacity in both HCC1934 and iCSCL10A cell lines. In clinical studies, H19 expression was associated with hormone negativity, tumor size, and nodal status. Patients with H19 expression had significantly poor disease-free survival (DFS) (26.3 vs. 64.8% at 5 years, p = 0.001) and overall survival (OS) (28.9 vs. 68.3% at 5 years, p = 0.004). The effect of H19 expression on prognosis was the most significant in triple-negative breast cancer compared to that in other subtypes (20.0 vs. 65.4% at 5 years DFS, p = 0.012, 20.0 vs. 69.2% at 5 years OS, p = 0.016). CONCLUSION: This study indicated that H19 was associated with stem cell phenotype in ALDH1-positive breast cancer. H19 regulates CSC and is associated with poor prognosis in breast cancer patients, particularly in triple-negative subtype.

Stable Liver Function during Long-Term Administration of Eltrombopag, a Thrombopoietin Receptor Agonist, in Patients with Chronic Liver Disease.

Liver cirrhosis is the end stage of chronic liver disease, but no definitive pharmacological treatment is currently available. It has been reported that thrombopoietin (TPO) promotes liver regeneration and improves liver cirrhosis by increasing platelet count. We have shown the direct effect of platelet transfusion on the improvement of liver function in patients with chronic liver disease. However, platelet transfusion often causes adverse events, such as platelet transfusion refractoriness and pruritus. Therefore, we conducted an exploratory clinical trial and administered eltrombopag, an orally bioavailable, small-molecule, non-peptide TPO receptor agonist that has been approved for the treatment of chronic idiopathic thrombocytopenic purpura. The study included five male patients, aged from 49 to 75 years (57.6 ± 10.4 years), with both chronic liver disease and hepatitis C virus infection, who presented with thrombocytopenia but without cancer. Eltrombopag, ranged from 6.25 to 50 mg/day (18.75 ± 18.22 mg/day), was administrated to the five patients during six months. All of the patients maintained platelet counts between 10 and 15 × 1010/L during the study. The indicators of liver function in patients were stable throughout the clinical trial, although we had predicted the same degree of the improvement of liver function, compared to platelet transfusion. Importantly, the liver volumes were also stable, and no cancerous lesions were observed. These results indicate the safety of long-term eltrombopag administration for patients with chronic liver disease and hepatitis C virus infection.

C1galt1-deficient mice exhibit thrombocytopenia due to abnormal terminal differentiation of megakaryocytes.

C1galt1 is essential for synthesis of the core 1 structure of mucin-type O-glycans. To clarify the physiological role of O-glycans in adult hematopoiesis, we exploited the interferon-inducible Mx1-Cre transgene to conditionally ablate the C1galt(flox) allele (Mx1-C1). Mx1-C1 mice exhibit severe thrombocytopenia, giant platelets, and prolonged bleeding times. Both the number and DNA ploidy of megakaryocytes in Mx1-C1 bone marrow were similar to those in wild-type (WT) mice. However, there were few proplatelets in Mx1-C1 primary megakaryocytes. Conversely, bone marrow transplanted from Mx1-C1 to WT and splenectomized Mx1-C1 mice gave rise to observations similar to those described above. The expression of GPIbα messenger RNA was unchanged in Mx1-C1 bone marrow, whereas flow cytometric and western blot analyses using megakaryocytes and platelets revealed that the expression of GPIbα protein was significantly reduced in Mx1-C1 mice. Moreover, circulating Mx1-C1 platelets exhibited an increase in the number of microtubule coils, despite normal levels of α- and ß-tubulin. Our observations suggest that O-glycan is required for terminal megakaryocyte differentiation and platelet production and that the decrease in GPIbα in cells lacking O-glycan might be caused by increased proteolysis.

Sphingosine 1-phosphate has anti-apoptotic effect on liver sinusoidal endothelial cells and proliferative effect on hepatocytes in a paracrine manner in human.

AIM: Sphingosine 1-phosphate (S1P) is a bioactive sphingolipid metabolite released from erythrocytes and platelets, and is a potent stimulus for endothelial cell proliferation. However, the role of S1P on human liver sinusoidal endothelial cells (LSEC) remains unclear. The proliferation and inhibition of apoptosis in LSEC are involved in the promotion of liver regeneration and the suppression of liver injury after liver resection and transplantation. The aim of this study is to investigate the role of S1P on human LSEC and the interaction between S1P and LSEC in hepatocyte proliferation in vitro. METHODS: Immortalized human LSEC were used. LSEC were cultured with S1P, and the cell proliferation, anti-apoptosis, signal transductions and production of cytokines and growth factors were subsequently examined. To investigate the interaction between S1P and LSEC in hepatocyte proliferation, primary human hepatocytes were cultured with the supernatants of LSEC with and without S1P. DNA synthesis and signal transductions in hepatocytes were examined. RESULTS: S1P induced LSEC proliferation through activation of Akt and extracellular signal-related kinase pathways and suppressed LSEC apoptosis by affecting the expression levels of Bcl-2, Bax and cleaved caspase-3. S1P promoted interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) production in LSEC. The supernatants of LSEC cultured with S1P enhanced hepatocyte DNA synthesis more strongly than the supernatants of LSEC cultured without S1P through activation of the signal transducer and activator of transcription-3 pathway. CONCLUSION: S1P has proliferative and anti-apoptotic effects and promotes the production of IL-6 and VEGF in human LSEC, thereby promoting hepatocyte proliferation.

1,8-Cineole Ameliorates Steatosis of Pten Liver Specific KO Mice via Akt Inactivation.

Hepatocyte-specific Phosphatase and tensin homolog (Pten)-knockout (KO) mice exhibit hepatic lesions analogous to non-alcoholic steatohepatitis (NASH). 1,8-cineole is a monoterpene oxide and it has several biological effects including hepatoprotective effects. In this study we revealed that 1,8-cineole ameliorates NASH of Pten KO mice. Pten KO mice were assigned to a control group without any medication or to a 1,8-cineole group injected with 50 mg/kg i.p. twice per week for eight weeks. At eight weeks, livers from each group were processed to measure triglyceride (TG) content, gene expression analysis, western blot analysis, and histological examination including Oil red O staining. 1,8-cineole ameliorated hepatic steatosis in Pten KO mice, revealed by TG content and Oil red O staining. Moreover, 1,8-cineole downregulated collagen 1a1 expression and improved liver fibrosis. Thus, 1,8-cineole has potential as a candidate to treat NASH by inactivating the Akt/PI3-kinase pathway.

Role of platelets in chronic liver disease and acute liver injury.

Platelets contain not only hemostatic factors but also many growth factors that play important roles in wound healing and tissue repair. Platelets have already been used for the promotion of tissue regeneration in the clinical setting, such as dental implantation and plastic surgery. Thrombocytopenia, which is frequently found in patients with chronic liver disease and cirrhosis, is due to various causes such as decreased thrombopoietin production and accelerated platelet destruction caused by hypersplenism. However, the relationship between thrombocytopenia and hepatic pathogenesis and the role of platelets in chronic liver disease are poorly understood. In acute liver injury, it is reported that platelets are recruited to the liver and contribute to liver damage by promoting the induction of chemotactic factors and the accumulation of leukocytes in the liver, whereas platelets or mediators released by platelets can have a protective effect against liver injury. In this review, we highlight the recent accumulated knowledge concerning the role of platelets in chronic liver disease and acute liver injury.

Interaction of kupffer cells and platelets determines the severity of ischemia-reperfusion injury in steatosis.

Liver steatosis increases the risk of postoperative complications following major liver resection, since the steatotic liver is susceptible to ischemia-reperfusion (IR) injury. However, it is unclear how IR injury changes in relation to the degree of hepatic steatosis. Previously, we reported that interaction between Kupffer cells (KCs) and platelets induced hepatic IR injury. The aim of our present study was to evaluate the relationship between the degree of liver steatosis and IR injury by focusing on the interaction of KCs and platelets. Mild and moderate steatotic liver models were generated in Wistar rats by feeding a choline-deficient diet for 2 and 4 weeks, respectively. The intensity of steatosis was defined based on the proportion of hepatocytes with fatty infiltration: normal (less than 5%), a mild steatosis (5-30%), and moderate steatosis (30-60%). All groups were subjected to 20 min of warm ischemia followed by 120 min of reperfusion. The number of adhesion of KCs to platelets in sinusoids was observed by intravital microscopy. IR injury was evaluated with serum alanine aminotransferase levels, histological findings, and sinusoidal perfusion. Compared to the normal liver, mild steatosis reduced the adhesion of KCs to platelets, inducing the attenuation of IR injury. In contrast, moderate steatosis increased the adhesion of KCs to platelets, aggravating IR injury relative to the normal liver. IR injury in the steatotic liver was not simply proportional to the degree of steatosis. Mild steatosis ameliorates IR injury compared to the normal liver, whereas moderate steatosis increases IR injury.

Signal transduction of platelet-induced liver regeneration and decrease of liver fibrosis.

Platelets contain three types of granules: alpha granules, dense granules, and lysosomal granules. Each granule contains various growth factors, cytokines, and other physiological substances. Platelets trigger many kinds of biological responses, such as hemostasis, wound healing, and tissue regeneration. This review presents experimental evidence of platelets in accelerating liver regeneration and improving liver fibrosis. The regenerative effect of liver by platelets consists of three mechanisms; i.e., the direct effect on hepatocytes, the cooperative effect with liver sinusoidal endothelial cells, and the collaborative effect with Kupffer cells. Many signal transduction pathways are involved in hepatocyte proliferation. One is activation of Akt and extracellular signal-regulated kinase (ERK)1/2, which are derived from direct stimulation from growth factors in platelets. The other is signal transducer and activator of transcription-3 (STAT3) activation by interleukin (IL)-6 derived from liver sinusoidal endothelial cells and Kupffer cells, which are stimulated by contact with platelets during liver regeneration. Platelets also improve liver fibrosis in rodent models by inactivating hepatic stellate cells to decrease collagen production. The level of intracellular cyclic adenosine monophosphate (cyclic AMP) is increased by adenosine through its receptors on hepatic stellate cells, resulting in inactivation of these cells. Adenosine is produced by the degradation of adenine nucleotides such as adenosine diphosphate (ADP) and adenosine tri-phosphate (ATP), which are stored in abundance within the dense granules of platelets.

Elovl6 promotes nonalcoholic steatohepatitis.

UNLABELLED: Nonalcoholic steatohepatitis (NASH) is associated with obesity and type 2 diabetes, and an increased risk for liver cirrhosis and cancer. ELOVL family member 6, elongation of very long chain fatty acids (Elovl6), is a microsomal enzyme that regulates the elongation of C12-16 saturated and monounsaturated fatty acids (FAs). We have shown previously that Elovl6 is a major target for sterol regulatory element binding proteins in the liver and that it plays a critical role in the development of obesity-induced insulin resistance by modifying FA composition. To further investigate the role of Elovl6 in the development of NASH and its underlying mechanism, we used three independent mouse models with loss or gain of function of Elovl6, and human liver samples isolated from patients with NASH. Our results demonstrate that (1) Elovl6 is a critical modulator for atherogenic high-fat diet-induced inflammation, oxidative stress, and fibrosis in the liver; (2) Elovl6 expression is positively correlated with severity of hepatosteatosis and liver injury in NASH patients; and (3) deletion of Elovl6 reduces palmitate-induced activation of the NLR family pyrin domain-containing 3 inflammasome; this could be at least one of the underlying mechanisms by which Elovl6 modulates the progress of NASH. CONCLUSION: Hepatic long-chain fatty acid composition is a novel determinant in NASH development, and Elovl6 could be a potential therapeutic target for the prevention and treatment of NASH.

Human platelets promote liver regeneration with Kupffer cells in SCID mice.

BACKGROUND: Platelets contain several growth factors, including vascular endothelial growth factor (VEGF) and insulin-like growth factor. We examined the role of human platelets in liver regeneration with a focus on Kupffer cells (KCs). MATERIALS AND METHODS: Severe combined immunodeficiency mice were subjected to 70% hepatectomy and phosphate-buffered saline administration (PBS); 70% hepatectomy and human platelet transfusion (hPLT); 70% hepatectomy, KC depletion, and PBS administration (KD + PBS); 70% hepatectomy, KC depletion, and human platelet transfusion (KD + hPLT); or a sham operation and human platelet transfusion (sham). The groups were evaluated for liver regeneration, accumulation and activation of human platelets in the liver, and/or co-localization of platelets and KCs. RESULTS: The liver-to-body weight ratio was significantly higher 48 h post-transfusion in the hPLT group compared with the PBS, KD + PBS, and KD + hPLT groups. Human VEGF concentrations were higher in liver tissues from the hPLT group, whereas VEGF was not detected in the other groups. Hepatic levels of KC-derived cytokines were elevated in the hPLT group compared with the PBS group. Molecules in signaling cascades downstream of these cytokines were phosphorylated earlier and more robustly in the hPLT group than in the PBS group. Activated human platelets accumulated in livers in the hPLT group, whereas fewer platelets accumulated and many were not activated in the sham and KD + hPLT groups. In the hPLT group, most human platelets were attached to KCs. CONCLUSIONS: Human platelet transfusion promoted liver regeneration in severe combined immunodeficiency mice. Together, human platelets and KCs resulted in growth factor release and enhanced liver regeneration.

Effects of thrombopoietin on growth of hepatocellular carcinoma: Is thrombopoietin therapy for liver disease safe or not?

AIM: Liver cirrhosis (LC) is the end stage of chronic liver disease. No definitive pharmacological treatment is currently available. We previously reported that thrombopoietin (TPO) promoted liver regeneration and improved liver cirrhosis by increasing platelet count. TPO is therefore considered to be a therapeutic agent for LC; however, it is unclear whether TPO has proliferative effects on hepatocellular carcinoma (HCC), which arises frequently in cirrhotic livers. In this study, we examined the effects of TPO on growth of HCC. METHODS: Expression of the TPO receptor, myeloproliferative leukemia virus oncogene (MPL) was examined in various liver tumor cell lines and liver cell types. In an in vitro study, the effects of TPO on signal transduction, cell proliferation, migration and invasion were examined in Huh7 cells, in which MPL is highly expressed. In an in vivo study, we subcutaneously transplanted Huh7 cells into nude mice that were divided into a TPO-treated group and a control group, and the tumor volume of each group was measured. RESULTS: MPL was expressed strongly in hepatocytes but not in other cell types. Among liver tumor cell lines, Huh7 showed the highest expression of MPL. In Huh7, the addition of TPO activated Akt phosphorylation but not cell proliferation, migration or invasion. In the mouse experiment, there was no significant difference in tumor volume between the two groups. CONCLUSION: TPO had no proliferative effect on HCC in vitro or in vivo, and could therefore be useful in the treatment of liver cirrhosis.

Platelet transfusion improves liver function in patients with chronic liver disease and cirrhosis.

Chronic liver disease (CLD), such as hepatitis C, is a progressive disease consisting of the destruction and regeneration of the liver parenchyma, leading to fibrosis and cirrhosis. Platelets contain various growth factors and may play important roles in liver regeneration. Thus, to investigate whether platelet transfusion improves liver function in patients with CLD and cirrhosis, we conducted an exploratory clinical trial. The study included 10 patients with CLD and cirrhosis (Child-Pugh class A or B), who all presented thrombocytopenia (platelet counts between 50,000 and 100,000 /µl). The subjects received 10 units of platelet concentrate once a week for 12 weeks. They were followed up for 9 months after the last transfusion. One patient discontinued platelet transfusion because of pruritus, and 2 patients discontinued because of platelet transfusion refractoriness. One patient was excluded from the analysis for receiving a procedural treatment after 12 platelet transfusions. Thus, the remaining 6 patients were analyzed. The platelet count did not increase significantly after the last transfusion. Significant improvement of serum albumin was observed at 1 month and 3 months after the last transfusion. Serum cholinesterase improved significantly at 1 week, 3 months, and 9 months after the last transfusion. Serum hyaluronic acid showed a tendency toward improvement after the last transfusion. In conclusion, platelet transfusion improved some of the indicators of liver function in patients with CLD and cirrhosis, though adverse events related to platelet transfusion were observed in some patients. Platelet increment therapy could be a new strategy for treating CLD and cirrhosis.

Novel therapy for liver regeneration by increasing the number of platelets.

Platelets are the smallest blood constitutes which contain three types of granules; alpha granules, dense granules, and lysosomal granules. Each granule contains various biophysiological substances such as growth factors, cytokines, etc. Platelets have been conventionally viewed as a trigger of inflammatory responses and injury in the liver. Some studies revealed that platelets have strong effects on promoting liver regeneration. This review presents experimental evidence of platelets in accelerating liver regeneration and describes three different mechanisms involved; (1) the direct effect on hepatocytes, where platelets translocate to the space of Disse and release growth factors through direct contact with hepatocytes, (2) the cooperative effect with liver sinusoidal endothelial cells, where the dense concentration of sphingosine-1-phosphate in platelets induces excretion of interleukin-6 from liver sinusoidal endothelial cells, and (3) the collaborative effect with Kupffer cells, where the functions of Kupffer cells are enhanced by platelets.

Interaction between Kupffer cells and platelets in the early period of hepatic ischemia-reperfusion injury--an in vivo study.

BACKGROUND: Hepatic ischemia-reperfusion (I/R) leads to activation of Kupffer cells (KCs). The activated KCs cause platelet and leukocyte adhesion to the sinusoidal endothelium. Previously, we reported that platelet-endothelium interactions occur earlier than leukocyte responses. The aim of this study was to evaluate the interaction between platelets and KCs in the hepatic microcirculation after I/R. MATERIALS AND METHODS: Sprague-Dawley rats were divided into three groups: the no-ischemia group (control group; n = 6); the 20-min ischemia group (I/R group; n = 6); and the 20-min ischemia + anti-rat platelet serum group (APS group; n = 6). KCs were labeled using the liposome entrapment method. The number of adherent platelets was observed for up to 120 min after reperfusion by intravital microscopy. To investigate the effects of platelets on I/R injury, rats were injected intravenously with rabbit APS for platelet depletion. RESULTS: In the I/R group, the number of adherent platelets increased significantly after I/R. More than 50% of the adherent platelets adhered to KCs. Electron microscopy indicated that the platelets attached to the KCs after hepatic ischemia. The histologic findings indicated liver damage and apoptosis of hepatocytes in zone 1. In the I/R group, but not in the control and APS groups, serum ALT increased immediately after reperfusion. CONCLUSIONS: We succeeded in visualizing the dynamics of both KCs and platelets in the hepatic sinusoids. Liver ischemia induced the adhesion of platelets to KCs in the early period, which could play a key role in reperfusion injury of the liver.

Development of the nervous system in mouse liver.

BACKGROUND: The role of the hepatic nervous system in liver development remains unclear. We previously created functional human micro-hepatic tissue in mice by co-culturing human hepatic endodermal cells with endothelial and mesenchymal cells. However, they lacked Glisson's sheath [the portal tract (PT)]. The PT consists of branches of the hepatic artery (HA), portal vein, and intrahepatic bile duct (IHBD), collectively called the portal triad, together with autonomic nerves. AIM: To evaluate the development of the mouse hepatic nervous network in the PT using immunohistochemistry. METHODS: Liver samples from C57BL/6J mice were harvested at different developmental time periods, from embryonic day (E) 10.5 to postnatal day (P) 56. Thin sections of the surface cut through the hepatic hilus were examined using protein gene product 9.5 (PGP9.5) and cytokeratin 19 (CK19) antibodies, markers of nerve fibers (NFs), and biliary epithelial cells (BECs), respectively. The numbers of NFs and IHBDs were separately counted in a PT around the hepatic hilus (center) and the peripheral area (periphery) of the liver, comparing the average values between the center and the periphery at each developmental stage. NF-IHBD and NF-HA contacts in a PT were counted, and their relationship was quantified. SRY-related high mobility group-box gene 9 (SOX9), another BEC marker; hepatocyte nuclear factor 4α (HNF4α), a marker of hepatocytes; and Jagged-1, a Notch ligand, were also immunostained to observe the PT development. RESULTS: HNF4α was expressed in the nucleus, and Jagged-1 was diffusely positive in the primitive liver at E10.5; however, the PGP9.5 and CK19 were negative in the fetal liver. SOX9-positive cells were scattered in the periportal area in the liver at E12.5. The Jagged-1 was mainly expressed in the periportal tissue, and the number of SOX9-positive cells increased at E16.5. SOX9-positive cells constructed the ductal plate and primitive IHBDs mainly at the center, and SOX-9-positive IHBDs partly acquired CK19 positivity at the same period. PGP9.5-positive bodies were first found at E16.5 and HAs were first found at P0 in the periportal tissue of the center. Therefore, primitive PT structures were first constructed at P0 in the center. Along with remodeling of the periportal tissue, the number of CK19-positive IHBDs and PGP9.5-positive NFs gradually increased, and PTs were also formed in the periphery until P5. The numbers of NFs and IHBDs were significantly higher in the center than in the periphery from E16.5 to P5. The numbers of NFs and IHBDs reached the adult level at P28, with decreased differences between the center and periphery. NFs associated more frequently with HAs than IHBDs in PTs at the early phase after birth, after which the number of NF-IHBD contacts gradually increased. CONCLUSION: Mouse hepatic NFs first emerge at the center just before birth and extend toward the periphery. The interaction between NFs and IHBDs or HAs plays important roles in the morphogenesis of PT structure.

Evaluation of immunosuppression protocols for MHC-matched allogeneic iPS cell-based transplantation using a mouse skin transplantation model.

BACKGROUND: Off-the-shelf major histocompatibility complex (MHC)-matched iPS cells (iPSC) can potentially initiate host immune responses because of the existence of numerous minor antigens. To suppress allo-immune responses, combination of immunosuppressants is usually used, but its efficacy to the allogeneic iPSC-based transplantation has not been precisely evaluated. METHODS: Three transplantation models were used in this study; MHC-matched, minor antigen-mismatched mouse skin or iPSC-graft transplantation, and fully allogeneic human iPSC-derived liver organoid transplantation in immune-humanized mice. The recipients were treated with triple drugs combination (TDC; tacrolimus, methylprednisolone, and mycophenolate mofetil) or co-stimulatory molecule blockade (CB) therapy with some modifications. Graft survival as well as anti-donor T and B cell responses was analyzed. RESULTS: In the mouse skin transplantation model, immunological rejection caused by the minor antigen-mismatch ranged from mild to severe according to the donor-recipient combination. The TDC treatment could apparently control the mild skin graft rejection when combined with a transient T cell depletion, but unexpected anti-donor T or B cell response was observed. On the other hand, CB therapy, particularly when combined with rapamycin treatment, was capable of attenuating both mild and severe skin graft rejection and allowing them to survive long-term without any unfavorable anti-donor immune responses. The efficacy of the CB therapy was confirmed in both mouse and human iPSC-derived graft transplantation. CONCLUSIONS: The findings suggest that the CB-based treatment seems suitable to well manage the MHC-matched allogeneic iPSC-based transplantation. The TDC-based treatment may be also used to suppress the rejection, but screening of its severity prior to the transplantation seems to be needed.

Platelets prevent acute hepatitis induced by anti-fas antibody.

BACKGROUND AND AIM: Platelets provide many functions in the body, especially to the liver. The purpose of this study is to investigate the effect of thrombocytosis with acute hepatitis induced by anti-Fas antibody and its mechanism. METHODS: Acute hepatitis was induced by administration of anti-Fas antibody in normal and thrombocytotic C57BL6J mice. For thrombocytosis, thrombopoietin; PEG-rHuMGDF was injected 5 days before and just prior to administration of anti-Fas antibody. To investigate the mechanisms, hepatocyte cell line (AML12) and sinusoidal endothelial cell line (M1) were induced apoptosis by staurosporine. They were cultured with platelets or thrombopoietin. Examination items were as follows: platelet number, alanine aminotransferase (ALT), histological findings, TUNEL (TdT-mediated dUTP-biotin Nick End Labeling) staining, and the expression of proteins associated with apoptosis in vivo and in vitro. RESULTS: Platelets were significantly increased in the thrombocytotic group (P < 0.01). Serum ALT levels were significantly reduced by thrombocytosis at 6, 24 and 72 h after the administration (P < 0.05). In histological findings, hemorrhagic necrosis was observed in the normal group, but not observed in the thrombocytotic group. TUNEL-positive hepatocytes were reduced and the expression of cleaved caspase-3 was significantly decreased in the thrombocytotic group. The phosphorylation of Akt, the increment of Bcl-xL and the decrease of cleaved caspase-3 were observed in AML12 cells cultured with platelets, but were not observed cultured with thrombopoietin. Platelets and thrombopoietin had no anti-apoptotic effect on M1 cells. CONCLUSION: Increase of platelets has a preventative effect against acute hepatitis induced by the anti-Fas antibody. It is suggested that platelets have a direct protective effect against apoptosis of hepatocytes.