Makoto Tokuhara

Adipose tissue-derived mesenchymal stem cells as a source of human hepatocytes

Recent observations indicate that several stem cells can differentiate into hepatocytes; thus, cell‐based therapy is a potential alternative to liver transplantation. The goal of the present study was to examine the in vitro hepatic differentiation potential of adipose tissue‐derived mesenchymal stem cells (AT‐MSCs). We used AT‐MSCs from different age patients and found that, after incubation with specific growth factors (hepatocyte growth factor [HGF], fibroblast growth factor [FGF1], FGF4) the CD105+ fraction of AT‐MSCs exhibited high hepatic differentiation ability in an adherent monoculture condition. CD105+ AT‐MSC‐derived hepatocyte‐like cells revealed several liver‐specific markers and functions, such as albumin production, low‐density lipoprotein uptake, and ammonia detoxification. More importantly, CD105+ AT‐MSC‐derived hepatocyte‐like cells, after transplantation into mice incorporated into the parenchyma of the liver. Conclusion: Adipose tissue is a source of multipotent stem cells that can be easily isolated, selected, and induced into mature, transplantable hepatocytes. The fact that they are easy to procure ex vivo in large numbers makes them an attractive tool for clinical studies in the context of establishing an alternative therapy for liver dysfunction. (HEPATOLOGY 2007;46:219–228.)

Rapid hepatic fate specification of adipose‐derived stem cells and their therapeutic potential for liver failure

Background and Aim:  Multipotential mesenchymal stem cells (MSC), present in many organs and tissues, represent an attractive tool for the establishment of a successful stem cell‐based therapy in the field of regeneration medicine. Adipose tissue mesenchymal stem cells (AT‐MSC), known as adipose‐derived stem cells (ASC) are especially attractive in the context of future clinical applications because of their high accessibility and minimal invasiveness during the procedure to obtain them. The goal of the present study was to induce human ASC into functional hepatocytes in vitro within a very short period of time and to check their therapeutic potential in vivo.

Is Percutaneous Cholecystostomy the Optimal Treatment for Acute Cholecystitis in the Very Elderly

In elderly patients emergent cholecystectomy for acute cholecystitis is a high risk procedure. We prospectively assessed the value of percutaneous cholecystostomy for acute cholecystitis in 38 consecutive elderly (≥ 80 years) patients. All 38 underwent percutaneous transhepatic cholecystostomy under ultrasonographic and fluoroscopic guidance for acute cholecystitis (25 calculous, 13 acalculous). Eight (21%) patients had acute severe medical problems, such as shock and respiratory distress. Thirty-one (82%) patients had chronic severe underlying diseases, including cardiovascular and neurologic diseases. Cholecystostomy was successful in all 38 patients. Prompt clinical improvement was obtained in 36 (95%) patients. Morbidity and mortality rates were 3% and 3%, respectively. After cholecystostomy, 10 patients with cholelithiasis underwent elective cholecystectomy without serious complications. Two patients underwent percutaneous cholecystolithotomy, which produced complete resolution of symptoms. Four of 12 patients with and none of 12 without cholelithiasis had recurrent cholecystitis after catheter removal during a mean follow-up of 1.8 years. A second cholecystostomy was successful in these four patients. Elderly patients are often poor surgical candidates because of severe cholecystitis or concomitant medical problems. Percutaneous cholecystostomy is a safe, effective treatment for acute cholecystitis even in elderly patients. For calculous cholecystitis, cholecystostomy can be followed by elective surgery, if possible, or by nonsurgical treatment or expectant conservative management in high-risk patients. Cholecystostomy may be a definitive treatment for acalculous cholecystitis.

Molecular Cloning of Human Frizzled-6

The Frizzled genes encode receptors for WNTs, secreted glycoproteins implicated in development as well as in carcinogenesis. In this paper, we report molecular cloning of Hfz6, the human homologue of Mfz6. Nucleotide sequence analysis showed that the Hfz6 gene encodes the 706 amino-acid protein with seven transmembrane domains, a cystein-rich domain in the N-terminal extracellular region, two N-linked glycosylation sites, and two cystein residues in the second and third extracellular loops. Hfz6 mRNA 4.4-kb in size was detected in various normal adult and fetal tissues, and a larger amount of Hfz6 mRNA was detected in both fetal lung and fetal kidney. The Hfz6 gene has been mapped to human chromosome 8q22.3-q23.1. In conclusion, we have cloned Hfz6, which encodes a seven-transmembrane receptor with the cystein-rich domain in the N-terminal extracellular region, but without the Ser/Thr-X-Val motif in the C-terminus.

Pdx1-transfected adipose tissue-derived stem cells differentiate into insulin-producing cells in vivo and reduce hyperglycemia in diabetic mice

Insulin-dependent diabetes mellitus (IDDM) is characterized by the rapid development of potentially severe metabolic abnormalities resulting from insulin deficiency. The transplantation of insulin-producing cells is a promising approach for the treatment of IDDM. The transcription factor pancreatic duodenal homeobox 1 (Pdx1) plays an important role in the differentiation of pancreatic beta cells. In this study, the human Pdx1 gene was transduced and expressed in murine adipose tissue-derived stem cells (ASCs). To evaluate pancreatic repair, we used a mouse model of pancreatic damage resulting in hyperglycemia, which involves injection of mice with streptozotocin (STZ). STZ-treated mice transplanted with Pdx1-transduced ASCs (Pdx1-ASCs) showed significantly decreased blood glucose levels and increased survival, when compared with control mice. While stable expression of Pdx1 in ASCs did not induce the pancreatic phenotype in vitro in our experiment, the transplanted stem cells became engrafted in the pancreas, wherein they expressed insulin and C-peptide, which is a marker of insulin-producing cells. These results suggest that Pdx1-ASCs are stably engrafted in the pancreas, acquire a functional beta-cell phenotype, and partially restore pancreatic function in vivo. The ease and safety associated with extirpating high numbers of cells from adipose tissues support the applicability of this system to developing a new cell therapy for IDDM.

Introduction of Sda Carbohydrate Antigen in Gastrointestinal Cancer Cells Eliminates Selectin Ligands and Inhibits Metastasis

The Sd(a) blood group carbohydrate structure is expressed in the normal gastrointestinal mucosa. We reported previously that the expression of Sd(a) carbohydrate structures and beta1,4-N-acetylgalactosaminyltransferase (beta1,4GalNAcT) activity responsible for Sd(a) synthesis were remarkably decreased in cancer lesions of the gastrointestinal tract. In this study, we found that Sd(a) antigen was expressed mainly in chief cells of normal stomach but not in cancer tissue by immunohistologic staining. In separated gastric mucosal cells, the Sd(a) glycolipids and beta1,4GalNAcT activity were concentrated in a fraction that contained chief cells as a major population. We cloned the cDNA encoding the glycosyltransferase that catalyzes the synthesis of Sd(a) (Sd(a)-beta1,4GalNAcT). Introduction of this cloned cDNA into KATO III gastric or HT29 colonic cancer cell lines, which originally expressed the E-selectin ligands, sialyl Lewis(x) and sialyl Lewis(a), resulted in a marked increase in cell-surface expression of Sd(a) along with the concomitant total loss of both sialyl Lewis(x) and sialyl Lewis(a). Both KATO III and HT29 cells transfected with the Sd(a)-beta1,4GalNAcT gene showed significantly decreased adhesion to activated human umbilical vein endothelial cells when compared with mock-transfected cells. Sd(a) determinants showed no direct binding to Siglec-3, -5, -7, and -9. These Sd(a)-beta1,4GalNAcT-transfected cells showed strikingly reduced metastatic potential in vivo when compared with mock-transfected cells. In summary, forced expression of Sd(a) carbohydrate determinant caused remarkable elimination of carbohydrate ligands for selectin and reduced metastasis of human gastrointestinal tract cancer cells.

Efficiently differentiating vascular endothelial cells from adipose tissue-derived mesenchymal stem cells in serum-free culture

Adipose tissue-derived mesenchymal stem cells (ASCs) have been reported to be multipotent and to differentiate into various cell types, including osteocytes, adipocytes, chondrocytes, and neural cells. Recently, many authors have reported that ASCs are also able to differentiate into vascular endothelial cells (VECs) in vitro. However, these reports included the use of medium containing fetal bovine serum for endothelial differentiation. In the present study, we have developed a novel method for differentiating mouse ASCs into VECs under serum-free conditions. After the differentiation culture, over 80% of the cells expressed vascular endothelial-specific marker proteins and could take up low-density lipoprotein in vitro. This protocol should be helpful in clarifying the mechanisms of ASC differentiation into the VSC lineage.

Magnetic resonance cholangiopancreatography for postoperative follow-up of intraductal papillary-mucinous tumors of the pancreas

BACKGROUND After resection of an intraductal papillary-mucinous tumor (IPMT), benign tumors or portions of the resected tumor are sometimes left in place to avoid total pancreatectomy. We evaluated the role of magnetic resonance cholangiopancreatography (MRCP) in postoperative follow-up. METHODS Twenty-two patients underwent MRCP 0.5 to 6.5 years after pancreatic resection for IPMT. RESULTS Two patients with surgical margin involvement of the main pancreatic duct showed mildly enhanced ductal dilatation due to anastomotic stenosis. In 4 patients with residual IPMT of the branch ducts, postoperative MRCP demonstrated no changes. MRCP revealed new IPMT 1 year after surgery in 1 patient. No patients showed intraductal or intracystic mural nodules postoperatively. In 3 patients with postoperative pancreatitis or recurrent abdominal discomfort, MRCP demonstrated ductal dilatation and poor secretin-stimulated pancreatic secretion into the gastrointestinal tract, which suggested pancreatoenterostomic stenosis. CONCLUSIONS MRCP is useful for postoperative follow-up of IPMT, in terms of investigating residual or recurrent IPMT and evaluating postpancreatectomy long-term complications.

N-Cadherin is a prospective cell surface marker of human mesenchymal stem cells that have high ability for cardiomyocyte differentiation

Mesenchymal stem cells (MSCs) are among the most promising sources of stem cells for regenerative medicine. However, the range of their differentiation ability is very limited. In this study, we explored prospective cell surface markers of human MSCs that readily differentiate into cardiomyocytes. When the cardiomyogenic differentiation potential and the expression of cell surface markers involved in heart development were analyzed using various immortalized human MSC lines, the MSCs with high expression of N-cadherin showed a higher probability of differentiation into beating cardiomyocytes. The differentiated cardiomyocytes expressed terminally differentiated cardiomyocyte-specific markers such as α-actinin, cardiac troponin T, and connexin-43. A similar correlation was observed with primary human MSCs derived from bone marrow and adipose tissue. Moreover, N-cadherin-positive MSCs isolated with N-cadherin antibody-conjugated magnetic beads showed an apparently higher ability to differentiate into cardiomyocytes than the N-cadherin-negative population. Quantitative polymerase chain reaction analyses demonstrated that the N-cadherin-positive population expressed significantly elevated levels of cardiomyogenic progenitor-specific transcription factors, including Nkx2.5, Hand1, and GATA4 mRNAs. Our results suggest that N-cadherin is a novel prospective cell surface marker of human MSCs that show a better ability for cardiomyocyte differentiation.

Development of Pancreatic Cancer, Disease-specific Mortality, and All-Cause Mortality in Patients with Nonresected IPMNs: A Long-term Cohort Study

PURPOSE To determine the cumulative incidence, disease-specific mortality, and all-cause mortality of pancreatic cancer (PC) in patients with intraductal papillary mucinous neoplasms (IPMNs) and to identify imaging findings that are associated with these outcomes. MATERIALS AND METHODS This retrospective study had institutional review board approval, and the need to obtain patient consent was waived. Data from an electronic database were analyzed and supplemented by chart reviews for 285 patients with nonresected IPMNs who were periodically followed up with imaging (1273 multidetector computed tomography and 750 magnetic resonance cholangiopancreatography examinations). The Kaplan-Meier method was used to estimate the cumulative development of PC, PC mortality, and all-cause mortality (factors were compared by using the log-rank test). RESULTS Over a median imaging follow-up period of 39 months, 12 (4.2%) of 285 patients developed PC; the cumulative 5-year PC incidence was 3.9% for branch duct (BD)-IPMNs, 45.5% for main duct (MD)-IPMNs (P < .01), 7.7% for cysts 30 mm or larger, and 5.3% for cysts smaller than 30 mm (P = .82). Over a median survival follow-up period of 47.5 months, seven (2.5%) of 285 patients died of PC and 14 (4.9%) patients died of other causes. Cumulative 5-year PC mortality was 2.1% for BD-IPMNs, 18.5% for MD-IPMNs (P < .01), 2.6% for cysts 30 mm or larger, and 2.8% for cysts smaller than 30 mm (P = .90). Cumulative 5-year all-cause mortality was 5.5% for BD-IPMNs, 18.5% for MD-IPMNs (P < .01), 12.5% for cysts 30 mm or larger, and 5.9% for cysts smaller than 30 mm (P = .89). CONCLUSION Five-year PC development, disease-specific mortality, and all-cause mortality were approximately 4%, 2%, and 6% for BD-IPMNs and 46%, 19%, and 19% for MD-IPMNs, respectively. The presence of an MD-IPMN, but not cyst size, was significantly associated with PC development and subsequent mortality.