Biomedical subjects

John K Fraser

Publications and source records attributed to John K Fraser.

10 recordsLinked to original sources

PubMed2006

Fat tissue: an underappreciated source of stem cells for biotechnology.

Adipose tissue can be harvested in large amounts with minimal morbidity. It contains numerous cells types, including adipocytes, preadipocytes, vascular endothelial cells and vascular smooth muscle cells; it also contains cells that have the ability to differentiate into several lineages, such as fat, bone, cartilage, skeletal, smooth, and cardiac muscle, endothelium, hematopoietic cells, hepatocytes and neuronal cells. Cloning studies have shown that some adipose-derived stem cells (ADSCs) have multilineage differentiation potential. ADSCs are also capable of expressing multiple growth factors, including vascular endothelial growth factor and hepatocyte growth factor. Early, uncontrolled, non-randomized clinical research, applying fresh adipose-derived cells into a cranial defect or undifferentiated ADSCs into fistulas in Crohn's disease, has shown healing and an absence of side effects. The combination of these properties, and the large quantity of cells that can be obtained from fat, suggests that this tissue will be a useful tool in biotechnology.

Adipose Tissue↗

PubMed2006

Plasticity of human adipose stem cells toward endothelial cells and cardiomyocytes.

Recent preclinical and clinical studies have suggested that adult stem cells have the ability to promote the retention or restoration of cardiac function in acute and chronic ischemia. Published clinical studies have used autologous donor cells, including skeletal muscle myoblasts, cultured peripheral blood cells, or bone marrow cells. However, our research and that of others indicates that human adipose tissue is an alternative source of cells with potential for cardiac cell therapy. These findings include the presence of cells within adipose tissue that can differentiate into cells expressing a cardiomyocytic or endothelial phenotype, as well as angiogenic and antiapoptotic growth factors. This potential is supported by preclinical studies in large animals.

Adipose Tissue↗

PubMed2005

Cellular therapy for disc degeneration.

STUDY DESIGN: Review article regarding the developing field of cellular therapies for symptomatic disc degeneration. OBJECTIVE: To review the rationale and discuss the results of cellular strategies that have been proposed or investigated for disc degeneration. SUMMARY OF BACKGROUND DATA: Disc degeneration is a substantial clinical problem. Disc degeneration begins with a loss of disc cells and alterations in the extracellular matrix of the disc. One promising approach for this problem involves the use of cells transplanted to the degenerative disc to achieve functional tissue repair. METHODS: The rationale for using cellular therapy for disc degeneration is discussed. The basic science studies involving cellular transplantation to the disc are reviewed and future directions of this line of research are discussed. RESULTS: Although substantial work remains, the future of cellular therapies for symptomatic disc degeneration appears promising. CONCLUSION: Continued research is warranted to further define the optimal cell type, scaffolds, and adjuvants that will allow successful disc repair in human patients.

Animals↗

PubMed2005

Results of the cord blood transplantation (COBLT) study unrelated donor banking program.

BACKGROUND: The goals of the Cord Blood Transplantation (COBLT) Study banking program initiated in 1996 were to develop standard operating procedures (SOPs) for cord blood (CB) donor recruitment and banking and to build an ethnically diverse unrelated CB bank to support a transplantation protocol. STUDY DESIGN AND METHODS: The program included collection centers, three banks, a steering committee, and a medical coordinating center (MCC) that developed and validated SOPs and a Web-based data collection system. External oversight was performed by the National Heart, Lung, and Blood Institute and the MCC. RESULTS: A total of 34,799 potential donors were screened and 20,710 consented. A total of 17,207 ethnically diverse units were collected between 1998 and 2001. A total of 11,077 (64%) units were cryopreserved and quarantined. Of these, 79 percent met eligibility criteria and were HLA-typed and entered into the search registry. Higher CB volumes and cell counts were obtained from cesarean sections compared to vaginal deliveries. Units from African American persons contained lower cell counts per volume compared to other ethnicities. Birth weight correlated with volume and cell content. External oversight was accomplished through custom reports generated by the data collection system and periodic site visits. During maintenance, a breach in the SOPs was detected during a site visit at one of the banks. These units were designated for future use in nonclinical research. CONCLUSION: The COBLT Study demonstrated that SOPs and data collection can be implemented in multiple banks coordinated by one MCC. Relationships between donor demographics and CB content may be useful in the development of other CB banking programs.

Blood Banks↗

PubMed2005

Multipotential differentiation of adipose tissue-derived stem cells.

Tissue engineering offers considerable promise in the repair or replacement of diseased and/or damaged tissues. The cellular component of this regenerative approach will play a key role in bringing these tissue engineered constructs from the laboratory bench to the clinical bedside. However, the ideal source of cells still remains unclear and may differ depending upon the application. Current research for many applications is focused on the use of adult stem cells. The properties of adult stem cells that make them well-suited for regenerative medicine are (1) ease of harvest for autologous transplantation, (2) high proliferation rates for ex vivo expansion and (3) multilineage differentiation capacity. This review will highlight the use of adipose tissue as a reservoir of adult stem cells and draw conclusions based upon comparisons with bone marrow stromal cells.

Adipose Tissue↗

PubMed2004

Adult stem cell therapy for the heart.

The purpose of this review is to summarize current data leading to and arising from recent clinical application of cellular therapy for acute myocardial infarct (heart attack) and congestive heart failure. We specifically focus on use of adult stem cells and compare and contrast bone marrow and adipose tissue; two different sources from which stem cells can be harvested in substantial numbers with limited morbidity. Cellular therapy is the latest in a series of strategies applied in an effort to prevent or mitigate the progressive and otherwise irreversible loss of cardiac function that frequently follows a heart attack. Unlike surgical, pharmacologic, and gene transfer approaches, cellular therapy has the potential to restore cardiac function by providing cells capable of regenerating damaged myocardium and/or myocardial function. Skeletal muscle myoblast expansion and transfer allows delivery of cells with contractile function, albeit without any evidence of cardiomyogenesis or electrical coupling to remaining healthy myocardium. Delivery of endothelial progenitor cells (EPCs) which drive reperfusion of infarct zone tissues is also promising, although this mechanism is directed at halting ongoing degeneration rather than initiating a regenerative process. By contrast, demonstration of the ability of adult stem cells to undergo cardiomyocyte differentiation both in vitro and in vivo suggests a potential for regenerative medicine. This potential is being examined in early clinical studies.

Adipose Tissue↗

PubMed2004

Autologous stem cells (adipose) and fibrin glue used to treat widespread traumatic calvarial defects: case report.

This is a report of a 7-year-old girl suffering from widespread calvarial defects after severe head injury with multifragment calvarial fractures, decompressive craniectomy for refractory intracranial hypertension and replantation of cryopreserved skull fragments. Chronic infection resulted in an unstable skull with marked bony defects. Two years after the initial injury the calvarial defects were repaired. Due to the limited amount of autologous cancellous bone available from the iliac crest, autologous adipose derived stem cells were processed simultaneously and applied to the calvarial defects in a single operative procedure. The stem cells were kept in place using autologous fibrin glue. Mechanical fixation was achieved by two large, resorbable macroporous sheets acting as a soft tissue barrier at the same time. The postoperative course was uneventful and CT-scans showed new bone formation and near complete calvarial continuity three months after the reconstruction.

Absorbable Implants↗

PubMed2003

Differential expression of stem cell mobilization-associated molecules on multi-lineage cells from adipose tissue and bone marrow.

Our laboratory has characterized a population of stromal cells obtained from adipose tissue termed processed lipoaspirate cells (PLAs). PLAs, like bone-marrow derived mesenchymal stem cells (BM-MSCs), have the capacity to differentiate along the adipogenic, osteogenic, chondrogenic, and myogenic lineages, In order to better characterize these two multi-lineage populations, we examined the surface phenotype of both bone marrow and adipose tissue-derived cells from five patients undergoing surgery. PLA and BM-MSC cells were isolated, subcultivated, and evaluated for cell surface marker expression using flow cytometry. PLA and BM-MSC cells both expressed CD13, CD29, CD44, CD90, CD105, SH-3, and STRO-1. Differences in expression were noted for cell adhesion molecules CD49d (Integrin alpha4), CD54 (ICAM-1), CD34, and CD106 (VCAM-1). While markedly similar, the surface phenotypes of PLA and BM-MSC cells are distinct for several cell adhesion molecules implicated in hematopoietic stem cell homing, mobilization, and proliferation.

Adipose Tissue↗

PubMed2002

Ex vivo expansion and clonality of CD34+ selected cells from bone marrow and cord blood in a serum-free media.

Although umbilical cord blood is increasingly being used in allogeneic marrow transplantation, delayed platelet engraftment is often a concern for cord blood transplant recipients. We evaluated the potential of ex vivo expansion and clonality in CD34+ cells separated from a bone marrow source, and cord blood, in a serum-free Media. The CD34+ cells, selected from bone marrow (BM) and umbilical cord blood (CB), were expanded with hematopoietic growth factors. They were then cultured for burst-forming units of erythrocytes (BFU-E), colony-forming units of granulocytes and monocytes (CFU-GM) and colony-forming units of megakaryocytes (CFU-Mk) at days 0, 4, 7, and 14 under the combination of growth factors, with cell counts. The cytokines included the recombinant human megakaryocyte growth and development (100 ng/ml), interleukin-3 (10 ng/ml), stem cell factor (100 ng/ml), flt-3 ligand (50 ng/ml) and interleukin-11 (200 ng/ml). The CB-selected CD34+ cells showed significantly higher total cell expansion than those from the BM at day 7 (3.0 fold increase than BM), day 14 (2.4 fold), and day 17 (2.6 fold). The colony count of the BFU-E/CFU-E per CD34+ cell at day 0 was 0.14 +/- 0.023 in the CB, which was significantly higher than 0.071 +/- 0.015 in the BM. The CB-selected CD34+ cells produced more BFU-E colonies than the BM on culture days 4, 7, and 14. The BFU-E colonies from the CB cells increased markedly on culture days 4 and 7, with a 4-fold increase at day 14. The colony count of the CFU-Mk per CD34+ cell at day 0 was 0.047 +/- 0.011 in the CB-selected CD34+ cells cultures, which was higher than the 0.026 +/- 0.014 in the BM. The CB-selected CD34+ cells produced more CFU-Mk colonies than the BM on culture days 4, 7 and 14. In conclusion, the ex vivo expansion of the CB cells may be very promising in producing total cellular expansion, CFU-Mk and BFU-E compared with BM, especially at day 7. The ex vivo expansion of the CB may have rationale in making an ex vivo culture for 7 to 14 d.

Antigens, CD34↗

PubMed2002

Human adipose tissue is a source of multipotent stem cells.

Much of the work conducted on adult stem cells has focused on mesenchymal stem cells (MSCs) found within the bone marrow stroma. Adipose tissue, like bone marrow, is derived from the embryonic mesenchyme and contains a stroma that is easily isolated. Preliminary studies have recently identified a putative stem cell population within the adipose stromal compartment. This cell population, termed processed lipoaspirate (PLA) cells, can be isolated from human lipoaspirates and, like MSCs, differentiate toward the osteogenic, adipogenic, myogenic, and chondrogenic lineages. To confirm whether adipose tissue contains stem cells, the PLA population and multiple clonal isolates were analyzed using several molecular and biochemical approaches. PLA cells expressed multiple CD marker antigens similar to those observed on MSCs. Mesodermal lineage induction of PLA cells and clones resulted in the expression of multiple lineage-specific genes and proteins. Furthermore, biochemical analysis also confirmed lineage-specific activity. In addition to mesodermal capacity, PLA cells and clones differentiated into putative neurogenic cells, exhibiting a neuronal-like morphology and expressing several proteins consistent with the neuronal phenotype. Finally, PLA cells exhibited unique characteristics distinct from those seen in MSCs, including differences in CD marker profile and gene expression.

Adipose Tissue↗