Promises and pitfalls in cell replacement therapy for heart failure.

Symptomatic heart failure is a complex clinical syndrome with a poor prognosis. Many efforts have been made to develop new therapeutic strategies to improve prognosis associated with heart failure. In this context, different stem cell populations for cardiac regenerative therapy have been examined recently. Here we discuss the potential strategies for using stem cells in cardiac regenerative therapy and the barriers that remain before an effective cell-based cardiac regenerative therapy can be employed clinically.

Manipulation of a VEGF-Notch signaling circuit drives formation of functional vascular endothelial progenitors from human pluripotent stem cells.

Human pluripotent stem cell (hPSC)-derived endothelial lineage cells constitutes a promising source for therapeutic revascularization, but progress in this arena has been hampered by a lack of clinically-scalable differentiation protocols and inefficient formation of a functional vessel network integrating with the host circulation upon transplantation. Using a human embryonic stem cell reporter cell line, where green fluorescent protein expression is driven by an endothelial cell-specific VE-cadherin (VEC) promoter, we screened for > 60 bioactive small molecules that would promote endothelial differentiation, and found that administration of BMP4 and a GSK-3ß inhibitor in an early phase and treatment with VEGF-A and inhibition of the Notch signaling pathway in a later phase led to efficient differentiation of hPSCs to the endothelial lineage within six days. This sequential approach generated > 50% conversion of hPSCs to endothelial cells (ECs), specifically VEC(+)CD31(+)CD34(+)CD14(-)KDR(high) endothelial progenitors (EPs) that exhibited higher angiogenic and clonogenic proliferation potential among endothelial lineage cells. Pharmaceutical inhibition or genetical knockdown of Notch signaling, in combination with VEGF-A treatment, resulted in efficient formation of EPs via KDR(+) mesodermal precursors and blockade of the conversion of EPs to mature ECs. The generated EPs successfully formed functional capillary vessels in vivo with anastomosis to the host vessels when transplanted into immunocompromised mice. Manipulation of this VEGF-A-Notch signaling circuit in our protocol leads to rapid large-scale production of the hPSC-derived EPs by 12- to 20-fold vs current methods, which may serve as an attractive cell population for regenerative vascularization with superior vessel forming capability compared to mature ECs.

Pregenerative medicine: developmental paradigms in the biology of cardiovascular regeneration.

The ability to create new functional cardiomyocytes is the holy grail of cardiac regenerative medicine. From studies using model organisms, new insights into the fundamental pathways that drive heart muscle regeneration have begun to arise as well as a growing knowledge of the distinct families of multipotent cardiovascular progenitors that generate diverse lineages during heart development. In this Review, we highlight this intersection of the "pregenerative" biology of heart progenitor cells and heart regeneration and discuss the longer term challenges and opportunities in moving toward a therapeutic goal of regenerative cardiovascular medicine.

High-speed analysis of multiplexed short tandem repeats with an electrophoretic microdevice.

We report the development of a robust and effective method for multiplexed short tandem repeat (STR) analysis within a chip-based microdevice. The method uses a laser-induced fluorescence detection system and simultaneously detects three- and four-color multiplexed polymerase chain reaction (PCR) samples. Analyses of the eight combined DNA index system (CODIS) STR loci were performed in 20 min with single-base-pair resolution ranging from 0.75 to 1. A simultaneous analysis of fifteen loci-ladders and a gender marker Amelogenin based on the PowerPlexTM 16 System was achieved in less than 35 min. The system is capable of repetitive operation and may be extended to high-throughput multilane devices that could be readily interfaced to an automated sample loading system.

Immunotherapy of spontaneous mammary carcinoma with fusions of dendritic cells and mucin 1-positive carcinoma cells.

The tumour-associated antigen mucin 1 (MUC1) is a multifunctional protein involved in protection of mucous membranes, signal transduction, and modulation of the immune system. More than 70% of cancers overexpress MUC1, making MUC1 a potential target for immunotherapy. In the present study, MUC1 transgenic mice were crossed with syngeneic strains that express the polyomavirus middle-T oncogene (PyMT) driven by the mouse mammary tumour virus promoter long-terminal repeat (MMTV-LTR). The resultant breed (MMT mice) developed spontaneous MUC1-expressing mammary carcinomas with 100% penetrance at 8-15 weeks of age. As found in human breast cancer, the mammary carcinoma in MMT mice arose in multiple stages. Immunization with fusions of dendritic cells and MUC1-positive tumour cells (FC/MUC1) induced MUC1-specific immune responses that blocked or delayed the development of spontaneous breast carcinomas. In contrast, there was no delay of tumour development in MMT mice immunized with irradiated MC38/MUC1 tumour cells. The efficacy of fusion cells was closely correlated with the timing of initial immunization. Immunization with FC/MUC1 initiated in MMT mice at < 1, 1-2 and 2-3 months of age rendered 33, 5 and 0% of mice free of tumour, respectively, up to 6 months. Whereas mice immunized in the later stage of tumour development succumbed to their disease, immunization resulted in control of tumour progression and prolongation of life. These results indicate that immunization with FC/MUC1 can generate an anti-MUC1 response that is sufficient to delay the development of spontaneous mammary carcinomas and control tumour progression in MMT mice.