Key Words: cardiomyogenesis Ⅲ human mesenchymal stem cell Ⅲ immunologic tolerance Ⅲ myocardial infarction Ⅲ cell-based therapy A lthough embryonic stem cells 1 and induced pluripotent stem (iPS) cells 2 can be differentiated into cells of various organs, including cardiomyocytes, there are many underlining problems to overcome before clinical applications can be used, eg, tumorigenicity. 3 Autografts of iPS cells may not cause immunologic rejection; ironically, however, possible neoplasm formation would cause a serious problem because the neoplasm would not be rejected by the withdrawal of immunosuppressive agents. On the other hand, mesenchymal stem cells (MSCs) have recently been used for clinical application, and their safety and feasibility in cardiac stem cell-based therapy have been demonstrated. 4 Thus, MSCs are a more important cellular source for stem cell-based therapy from a practical point of view.The efficacy of human bone marrow-derived MSCs (BMMSCs) was still limited, 5 however, because of low efficiency for cardiomyogenic transdifferentiation. 6 We previously reported that non-marrow-derived mesenchymal cells had higher cardiomyogenic transdifferentiation efficiency, eg, menstrual blood-derived mesenchymal cells (MMCs), 7 umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs), 8 and placental chorionic plate-derived mesenchymal cells (PCPCs). 9 These cells are thought to be used by an allograft; therefore, problems of immunologic rejection arise. However, an allograft may be superior to an autograft in several ways. Taking into account the background condition of the patient (eg, metabolic disease or age), Original received July 16, 2009; revision received April 14, 2010; accepted April 22, 2010 16 reported significant recovery of cardiac function by the rat amnion-derived cell transplantation in rat myocardial infarction (MI) model, however, they failed to show clear evidence of cardiomyogenic differentiation in vivo. Therefore, in the present study, we attempted to show: (1) the powerful cardiomyogenic transdifferentiation potential of our isolated hAMCs, and the beneficial effect of transplantation of hAMCs on cardiac function in vivo; (2) the induction of immunologic tolerance so that hAMCs can be a powerful allograftable stem cell source without either the administration of immunosuppressive agents or matching of MHC typing; (3) the mechanism of induction of tolerance; and (4) the close relationship between the cardiomyogenic transdifferentiation of mesenchymal cells and the process of immunologic tolerance. MethodsAn expanded Methods section is available in the Online Data Supplement at http://circres.ahajournals.org. Isolation and Culture of Human Amniotic Membrane-Derived Mesenchymal CellsHuman amniotic membrane was collected, with informed consent from individual patients, after delivery of a male neonate. The study was approved by the ethics committee of Keio University School of Medicine. The precise methods for culture have been described previously. 9,17 Detail is shown in...

Gibberellin A 1 (GA1), 3-epi-GAl, GA17, GA19, GA2o, and GA77 were identified by Kovats retention indices and full-scan mass spectra from gas chromatography-mass spectrometry analysis of a purified extract of mature seeds of photoblastic lettuce (Lactuca sativa L. cv. Grand Rapids). Non-13-hydroxylated GAs such as GA 4 and GA 9 were not detected even by highly sensitive radioimmunoassay. These results show that the major biosyn-

The efficacy of transplantation of default human marrowderived mesenchymal stem cells (MSCs) was modest. In this study, our challenge was to improve the efficacy of MSC transplantation in vivo by pretreatment of MSCs with pioglitazone. MSCs were cultured with or without medium containing 1 lM of pioglitazone before cardiomyogenic induction. After cardiomyogenic induction in vitro, cardiomyogenic transdifferentiation efficiency (CTE) was calculated by immunocytochemistry using anti-cardiac troponin-I antibody. For the in vivo experiments, myocardial infarction (MI) at the anterior left ventricle was made in nude rats. Two weeks after MI, MSCs pretreated with pioglitazone (p-BM; n 5 30) or without pioglitazone (BM; n 5 17) were injected, and then survived for 2 weeks. We compared left ventricular function by echocardiogram and immunohistochemistry to observe cardiomyogenic transdifferentiation in vivo. Pretreatment with pioglitazone significantly increased the CTE in vitro (1.9% 6 0.2% n 5 47 vs. 39.5% 6 4.7% n 5 13, p < .05). Transplantation of pioglitazone pretreated MSCs significantly improved change in left ventricular % fractional shortening (BM; 24.8% 6 2.1%, vs. p-BM; 5.2% 6 1.5%). Immunohistochemistry revealed significant improvement of cardiomyogenic transdifferentiation in p-BM in vivo (BM; 0% 6 0% n 5 5, vs. p-BM; 0.077% 6 0.041% n 5 5). Transplantation of pioglitazonepretreated MSCs significantly improved cardiac function and can be a promising cardiac stem cell source to expect cardiomyogenesis.

We have encountered a paternity case where exclusion of the putative father was only observed in the ABO blood group (mother, B; child, A1; putative father, O), among the many polymorphic markers tested, including DNA fingerprints and microsatellite markers. Cloning a part of the ABO gene, PCR-amplified from the trio's genomes, followed by sequencing the cloned fragments, showed that one allele of the child had a hybrid nature, comprising exon 6 of the B allele and exon 7 of the O1 allele. Based on the evidence that exon 7 is crucial for the sugar-nucleotide specificity of A1 and B transferases and that the O1 allele is only specified by the 261G deletion in exon 6 of the consensus sequence of the A1 allele, we concluded that the hybrid allele encodes a transferase with A1 specificity, resulting, presumably, from de novo recombination between the B and O1 alleles of the mother during meiosis. Screening of random populations demonstrated the occurrence of four other hybrid alleles. Sequencing of intron VI from the five hybrid alleles showed that the junctions of the hybrid alleles were located within intron VI, the intron VI-exon 7 boundaries, or exon 7. Recombinational events seem to be partly involved in the genesis of sequence diversities of the ABO gene.

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To improve the modest efficacy of mesenchymal stem cell (MSC) transplantation, the treatment of human MSCs with angiotensin receptor blockers (ARBs) was investigated. MSCs were cultured with or without the medium containing 3 μmol/l of ARBs before cardiomyogenic induction. After cardiomyogenic induction in vitro, cardiomyogenic transdifferentiation efficiency (CTE) was calculated by immunocytochemistry using anticardiac troponin‐I antibody. In the nude rat chronic myocardial infarction model, we injected MSCs pretreated with candesartan (A‐BM; n = 18) or injected MSCs without pretreatment of candesartan (BM; n = 25), each having survived for 2 weeks. The left ventricular function, as measured by echocardiogram, was compared with cardiomyogenic transdifferentiation in vivo, as determined by immunohistochemistry. Pretreatment with ARBs significantly increased the CTE in vitro (10.1 ± 0.8 n = 12 vs. 4.6 ± 0.3% n = 25, p < .05). Transplantation of candesartan‐pretreated MSCs significantly improved the change in left ventricular ejection fraction (BM; −7.2 ± 2.0 vs. A‐BM; 3.3 ± 2.3%). Immunohistochemistry revealed significant improvement of cardiomyogenic transdifferentiation in A‐BM in vivo (BM; 0 ± 0 vs. A‐BM; 0.014 ± 0.006%). Transplantation of ARB‐pretreated MSCs significantly improved cardiac function and can be a promising cardiac stem cell source from which to expect cardiomyogenesis. STEM CELLS 2011;29:1405–1414

The janus kinases (JAK) and signal transducers and activators of the transcription (STAT) pathway have been shown to be activated by a number of cytokines or growth factors and to play significant roles in the differentiation of various cell types. In the present study, we investigated the distribution of the JAK-STAT pathway using immunohistochemistry in the human epidermis. Each element of the pathway showed abundant and differential expression in the epidermis. The differential distribution of the elements was most strikingly observed in the horny keratinised cell and granular layers of the epidermis. JAK2, JAK3, STAT1 and STAT5 were expressed in high amounts, and JAK1, TYK2, STAT2, STAT3, STAT4 and STAT6 to a much lesser extent in the horny cell layer. JAK3, TYK2, STAT2, STAT3, STAT4 and STAT6 were more abundantly expressed in the granular layer than the lower layers of the epidermis. JAK1, STAT1 and STAT5 were expressed at almost the same levels in the various layers of the epidermis. These results show that elements of the JAK-STAT pathway are abundantly and differentially expressed in the epidermis. It is suggested that each element of the pathway may play a role at a distinct stage of keratinocyte differentiation.Key words : Skin ; keratinocyte differentiation. The janus kinases (JAK) and signal transducers and activators of the transcription (STAT) signalling pathway have been shown to be activated by a number of cytokines, growth factors, and oncogenic tyrosine kinases (Ihle, 1995). JAKs associate with the intracellular domains of particular receptors and become activated by ligand binding to the receptors at the cell surface. Activated JAKs consecutively phosphorylate STATs at distinct tyrosine residues. The tyrosine-phosphorylated STATs leave the receptor complex, translocate to the nucleus, and promote the transcriptional activation of ligand-inducible genes (Darnell, 1997). To date, 4 members of the JAK family (JAK1, JAK2, JAK3 and TYK2) and 7 of the STAT family (STAT1, STAT2, STAT3, STAT4, STAT5a, STAT5b and STAT6) have been identifiedCorrespondence to Dr Koichi Suzuki, Department of Legal Medicine, Osaka Medical College, 2-7 Daigaku, Takatsuki, 569-8686, Japan. Tel. : j81 726 831221 ; fax : j81 726 846515 ; e-mail : leg010!art.osaka-med.ac.jp (Ihle, 1995). The pathway has been demonstrated to play significant roles in determining differentiation processes of a variety of cell types, including myeloid leukaemia cells Nakajima et al. 1996 ;Yamanaka et al. 1996), murine mammary epithelial cells (Liu et al. 1997), helper T cells (Shimoda et al. 1996Takeda et al. 1996), murine haematopoietic cells (Rane & Reddy, 1994) and rat hepatocytes (Runge et al. 1998).The epidermis provides a useful model for investigating the differentiation process. In the epidermis, the outer (horny cell) layers of terminally differentiated cells are repopulated from a basal layer of proliferating keratinocytes. The proliferating keratinocytes are released from the substratum, migrate outwards and enter a...

This study concerns whether advanced glycation endproducts (AGE) are related to microvascular derangement in diabetes, exemplified by pericyte loss and angiogenesis in retinopathy and by mesangial expansion in nephropathy. AGE caused a decrease in viable pericytes cultivated from bovine retina. On the other hand, AGE stimulated the growth and tube formation of human microvascular endothelial cells (EC), this being mediated by autocrine vascular endothelial growth factor. In AGE‐exposed rat mesangial cells, type IV collagen synthesis was induced. Those AGE actions were dependent on a cell surface receptor for AGE (RAGE), because they were abolished by RAGE antisense or ribozyme. The AGE‐RAGE system may thus participate in the development of diabetic microangiopathy. This proposition was supported by experiments with animal models; several indices characteristic of retinopathy were correlated with circulating AGE levels in OLETF rats. The predisposition to nephropathy was augmented in RAGE transgenic mice when they became diabetic.