Kenji Okumura

Flow cytometric isolation of endodermal progenitors from mouse salivary gland differentiate into hepatic and pancreatic lineages

Experimental injury is useful to induce tissue stem cells, which may exist in small numbers under normal conditions. The salivary glands originate from the endoderm and consist of acinar and ductal epithelial cells, which have exocrine function. After salivary gland duct ligation, acinar cells disappear as a result of apoptosis, and duct epithelium subsequently proliferates. In this study, we analyzed the tissue stem cells induced by salivary gland duct ligation in mice using immunohistochemistry and flow cytometry. We sorted the Sca‐1+/c‐Kit+ fraction from adult mice salivary glands by way of fluorescence‐activated cell sorting. The sorted cells were apparently homogeneous and were designated mouse salivary gland–derived progenitors (mSGPs). mSGP cells differentiated into a hepatic lineage when cultured in matrigel. In spherical culture in the presence of glucagon‐like peptide‐1 (GLP‐1), these cells differentiated into a pancreatic endocrine lineage. When spheroidal bodies of mSGP, 20 to 30 μm in diameter, were transplanted into liver via the portal vein, the cells integrated into hepatic cords and expressed albumin and α1‐antitrypsin, suggesting that they had differentiated into hepatic‐type cells. Moreover, ductlike structures formed by mSGP cells also appeared, epithelial cells of which were positive for cytokeratin 19. In conclusion, fluorescence‐activated cell sorting (FACS) based on histologic evidence is efficient in isolating adult tissue stem cells of the salivary gland. Tissue stem cells of endodermal origin (e.g., hepatic oval cells, pancreatic epithelial progenitor cells, and salivary gland progenitor cells) have similarities in their molecular markers and tissue location. Our findings suggest the existence of common tissue stem cells in endoderm‐derived organs. (HEPATOLOGY 2004;39:667–675.)

Capability of Tissue Stem Cells to Organize into Salivary Rudiments

Branching morphogenesis (BrM), an essential step for salivary gland development, requires epithelial-mesenchymal interactions. BrM is impaired when the surrounding mesenchyme is detached from the salivary epithelium during the pseudoglandular stage. It is believed that the salivary mesenchyme is indispensable for BrM, however, an extracellular matrix gel with exogenous EGF can be used as a substitute for the mesenchyme during BrM in the developing salivary epithelium. Stem/progenitor cells isolated from salivary glands in humans and rodents can be classified as mesenchymal stem cell-like, bone-marrow-derived, duct cell-like, and embryonic epithelium-like cells. Salivary-gland-derived progenitor (SGP) cells isolated from duct-ligated rats, mice, and swine submandibular glands share similar characteristics, including intracellular laminin and α6β1-integrin expression, similar to the embryonic salivary epithelia during the pseudoglandular stage. Progenitor cells also isolated from human salivary glands (human SGP cells) having the same characteristics differentiate into hepatocyte-like cells when transplanted into the liver. Similar to the dissociated embryonic salivary epithelium, human SGP cells aggregate to self-organize into branching organ-like structures on Matrigel plus exogenous EGF. These results suggest the possibility that tissue stem cells organize rudiment-like structures, and the embryonic cells that organize into whole tissues during development are preserved even in adult tissues.

Production of Cloned Pigs from Salivary Gland-Derived Progenitor Cells

To achieve tissue stem cell transplantation in clinical settings, translational studies using large animal models are essential to confirm the efficacy and safety of therapy. Therefore, with the ultimate objective of constructing a porcine model of stem cell transplantation in the present study we attempted to clone pigs using porcine salivary gland-derived progenitor cells (pSGPs) as nuclear donors. Normal chromosomal compositions of pSGPs were maintained after five to eight passages (73%, 41 of 56). Cell cycle was efficiently synchronized in G(0)/G(1) phase after 2 days of serum-starved culture (79%). Characteristics of multipotent pSGPs, that is, CD49f and intracellular laminin staining patterns, were unchanged after serum-starved culture. Developmental rate of blastocysts from embryos reconstructed using pSGPs as nuclear donors was significantly higher when compared to embryos reconstructed using fetal fibroblasts (27.7%, 38 of 137 vs. 12.8%, 17 of 138; p < 0.05). When a total of 615 reconstructed embryos were transplanted into four recipient gilts, all gilts became pregnant and produced 12 piglets. These findings suggest that pSGPs represent appropriate donor cells for porcine somatic cell nuclear transfer.

Current state of domino transplantation in Japan in terms of surgical procedures and de novo amyloid neuropathy

The status of domino liver transplantation (DLT) in Japan was evaluated. DLT and familial amyloidotic polyneuropathy (FAP) recipients who underwent living donor liver transplantation (LDLT) at Kumamoto University were reviewed with attention to surgical procedures. Thirty-nine DLTs were performed in Japan until 2010, and survival rates at 1 and 3 years were 82% and 63.6%, respectively. Six of 21 DLT recipients who survived for more than 3 years developed amyloid depositions within organs, and de novo amyloid neuropathy was reported in three patients. DLT from FAP recipients in Kumamoto was safely performed with preservation of the retrohepatic inferior vena cava in FAP recipients. All 20 FAP recipients who were DLT donors are alive with the exception of one who died of the original FAP 9 years after LDLT. The outcomes of DLT and FAP recipients in Kumamoto were satisfactory.

Liver transplant from an ABO-incompatible and hepatitis C antibody-positive but an HCV-RNA negative living donor in a familial amyloid polyneuropathy patient.

Familial amyloid polyneuropathy is a rare, progressively disabling, and ultimately fatal inherited disease. Liver transplant is currently the only available treatment proven to halt the progression of familial amyloid polyneuropathy. We report a 31-year-old woman with familial amyloid polyneuropathy who received a living-donor liver transplant from her husband who was hepatitis C virus antibody-positive but HCV-RNA negative and ABO incompatible. Six years after the transplant, both donor and recipient have normal liver biochemistry results; no hepatitis C viral load has been detectable in the recipient. This is the first report of a living ABO-incompatible liver transplant from an anti-hepatitis C virus antibody-positive but an HCV-RNA negative donor. This experience suggests that the use of an anti-hepatitis C virus antibody-positive hepatic graft is possible in select circumstances.

Drainage of subcutaneous lymphatic fluid for the management of respiratory distress in a case of generalized lymphangiectasia in an infant

A 10-month-old girl was referred to our hospital because of congenital and persistent bilateral chylothorax and generalized lymphedema as well as long-standing respiratory disturbance. Radiological studies showed a diffuse network of superficial lymphatic vessels without major trunks throughout her entire body as well as the lung. She was diagnosed with systemic lymphangiomatosis complicated with pulmonary lymphangiectasia. Percutaneous puncture in the lower leg was performed to discharge the lymphatic fluid and proved to be effective for the respiratory disturbance. This procedure is safe and easy and effectively improves the quality of life of the patient and the family in case of such a persistent disease.

A thoracoabdominal approach in revision of the hepatic hilum after left lobe living donor liver transplantation

We present an approach to safely expose the hepatic hilum for revision procedures after left lobe living donor liver transplantation. A 14-year-old adolescent girl who had undergone left lobe living donor liver transplantation experienced repeated episodes of cholangitis. Because treatment with interventional techniques failed, surgical revision was indicated. The right thoracoabdominal approach was selected to minimize dissection. Intraoperative findings showed adhesive kinking of the Roux-Y limb just distal to the bilioenteric anastomosis, and a side-to-side jejunojejunostomy was performed. The thoracoabdominal approach leads to easy and excellent reoperative exposure of the hilar site of a left lobe liver graft.

Living donor liver transplantation as a means of rescuing post-embolization hepatic failure in a patient with idiopathic intrahepatic arteriovenous malformation in the liver

Interventional radiology used to be a first-line treatment for cardiac failure caused by idiopathic hepatic arteriovenous malformation (AVM). Here, we report a 64-year-old male patient treated by living donor liver transplantation (LDLT) following failed hepatic artery embolization for idiopathic hepatic AVM. Hepatic artery reconstruction in LDLT was very difficult in this case due to the adverse effects of the pre-transplant intervention. In the treatment of widespread AVM in the liver, arterial embolization should be avoided and primary liver transplantation should be considered.