Biomedical subjects

Ying Long Liu

Publications and source records attributed to Ying Long Liu.

6 recordsLinked to original sources

PubMed2007

In vitro and in vivo differentiation of human umbilical cord derived stem cells into endothelial cells.

The successful use of tissue-engineered transplants is hampered by the need for vascularization. Recent advances have made possible the using of stem cells as cell sources for therapeutic angiogenesis, including the vascularization of engineered tissue grafts. The goal of this study was to examine the endothelial potential of human umbilical cord-derived stem (UCDS) cells. UCDS cells were initially characterized and differentiated in an endothelial differentiation medium containing VEGF and bFGF. Differentiation into endothelial cells was determined by acetylated low-density lipoprotein incorporation and expression of endothelial-specific proteins, such as PECAM and CD34. In vivo, the transplanted UCDS cells were sprouting from local injection and differentiated into endothelial cells in a hindlimb ischemia mouse model. These findings indicate the presence of a cell population within the human umbilical cord that exhibits characteristics of endothelial progenitor cells. Therefore, human umbilical cord might represent a source of stem cells useful for therapeutic angiogenesis and re-endothelialization of engineered tissue grafts.

Adipocytes↗

PubMed2006

Simultaneous enlargement of the pulmonary annulus and the pulmonary cusp with autologous pericardium in right ventricular outflow tract reconstruction.

BACKGROUND: Surgical repair of obstructive lesions of the right ventricular outflow tract (RVOT) commonly creates pulmonary valve incompetence, which continues to stimulate research for the optimal materials and surgical techniques to reconstruct RVOT. In this study, we present the early results with simultaneous enlargement of the pulmonary annulus and the pulmonary cusp with a transannular patch of autologous pericardium in RVOT reconstruction. PATIENTS AND METHODS: From January 2003 to December 2005, the surgical technique of simultaneous enlargement of the pulmonary annulus and the pulmonary cusp was used in 32 patients who had complex congenital heart anomalies with pulmonary artery hypoplasia. The functional status of the patients was followed up in the cardiologic clinic of our institute. The motion of the newly constructed valve and the degree of pulmonary insufficiency were evaluated by echocardiography before discharge and at 2-6 months, 12 months, and 36 months postoperatively. RESULTS: Early death occurred in one patient (3.1%). Postoperative complications occurred in six patients but they recovered uneventfully. During the follow-up, 28 of 31 operative survivors were in New York Heart Association functional class I without medication and the other three were in class II. Seventeen patients had no or trivial pulmonary regurgitation; mild regurgitation was present in 12 patients, and moderate regurgitation was seen in 2 patients. None of these patients needed reoperation and echocardiography showed good motion of the reconstructed valve. CONCLUSIONS: The surgical technique of simultaneous enlargement of the pulmonary annulus and the pulmonary cusp with a transannular patch of autologous pericardium is a safe, reliable, and effective way for RVOT reconstruction. Satisfactory early results have been achieved; however, long-term follow-up is necessary to determine the true value of this technique.

Adolescent↗

PubMed2006

Cellular therapy and myocardial tissue engineering: the role of adult stem and progenitor cells.

Acquired cardiovascular diseases and complex congenital heart diseases are leading causes of morbidity and mortality. Cellular therapy and tissue engineering are emerging as promising alternative approaches to treat cardiovascular diseases. Cellular therapy involves isolating cells and delivering the cells to the site of cardiac injury to restore blood flow and contractility to previously infarcted, scarred or dysfunctional heart. Myocardial tissue engineering, engineered heart tissue by seeding cells in three-dimensional matrices of biodegradable polymers or cell sheet engineering without artificial scaffolds to form new myocardial constructs. Questions are common to both these approaches, such as the best cell source and optimal conditions for therapeutic application. The capabilities of stem cells for pluripotency and long-term self-renewal make it an ideal source for myocardial tissue engineering and cell therapy. We review the current understanding of postnatal adult stem and progenitor cells in cellular therapy and myocardial tissue engineering from a surgical view point, and highlight the latest advances in these exciting fields.

Adult↗

PubMed2006

Human umbilical cord derived stem cells for the injured heart.

The limited ability of the heart to regenerate damaged tissue following a myocardial infarct results in progressive dysfunctions and consequently leads to heart failure. Cell therapy with stem cells for cardiac repair is emerging as an alternative strategy and demonstrates promising results. Recent advances suggest human umbilical cord may be a new source for stem cells. Human umbilical cords are easy to obtain and umbilical cord derived stem cells can be easily extracted and cryopreserved, allowing for individuals to store their own samples for possible future autologous use even if there were no immediate indication that stem cell therapy would be required. Therefore, we hypothesize that human umbilical cord derived stem cells may be the new cell source for the injured heart.

Cell Differentiation↗

PubMed2006

Stem cells: new cell source for myocardial constructs tissue engineering.

Cardiovascular diseases like myocardial infarction, complex congenital heart disease, and subsequent heart failure are a leading cause of morbidity and mortality. Recent advances in tissue engineering arise to address the lack of available tissues and organs for transplantation because cells alone are not capable of recreating complex tissues upon transplantation. Consequently, a very promising approach to repair large scar areas and congenital heart defects may be the use of tissue engineering, in which cells are seeded in three-dimensional matrices of biodegradable polymers to form myocardial constructs. In recent years, there has been a tremendous increase in the understanding of stem cell biology. Stem cells have clonogenic and self-renewing capabilities, and under certain conditions, can differentiate into multiple cell lineages. Recent studies have shown that stem cells can be isolated from a wide variety of tissues, including bone marrow, peripheral blood, muscle, and adipose tissue. We hypothesize that tissue-engineered myocardial constructs with stem cells may fulfill the requirements of native heart muscle and, in the long run, may allow replacement of the injured heart and repair of congenital cardiac defects possible.

Animals↗

PubMed2006

Application of stem cells for cardiovascular grafts tissue engineering.

Congenital and acquired heart diseases are leading causes of morbidity and mortality world-wide. Currently, the synthetic materials or bioprosthetic replacement devices for cardiovascular surgery are imperfect and subject patients to one or more ongoing risks including thrombosis, limited durability and need for reoperations due to lack of growth in children and young adults. Suitable replacement grafts should have appropriate characteristics, including resistance to infection, low immunogenicity, good biocompatability and thromboresistance, with appropriate mechanical and physiological properties. Tissue engineering is a new scientific field aiming at fabrication of living, autologous grafts having structure or function properties that can be used to restore, maintain or improve tissue function. The use of autologous stem cells in cardiovascular tissue engineering is quite promising due to their capacity of self-renewal, high proliferation, and differentiation into specialized progeny. Progress has been made in engineering the various components of the cardiovascular system, including myocardial constructs, heart valves, and vascular patches or conduits with autologous stem cells. This paper will review the current achievements in stem cell-based cardiovascular grafts tissue engineering, with an emphasis on its clinical or possible clinical use in cardiovascular surgery.

Animals↗