Osteoporosis is a systemic skeletal disease that affects millions of people worldwide. There are many possible etiologies for osteoporosis, including inherent variables like genetics and sex, and lifestyle variables like diet and exercise. Characterized by low bone mass and increased fracture risk, the disease places a burden on both the patients and the healthcare industry. Therefore, it is vital that research determine the mechanisms by which the risk factors affect BMD so that better diagnosis and treatment options may be developed. The purpose of this study was to examine the relationship between various osteoporosis risk factors and biochemical markers of osteogenic cell activity derived from bone-marrow MSCs. It was hypothesized postmenopausal white women, having the greatest risk for osteoporosis, would have elevated hydroxyproline and decreased ALP, indicative of greater bone resorption. Acetabular reamings were collected from 26 patients (15 males and 11 females) undergoing total hip arthroplasty at Boston Medical Center. MSCs from the reamings were plated and underwent osteoinduction into osteoblasts. The cells were then harvested and assayed for various indicators of cell growth and bone cell activity, such as DNA, ALP, and hydroxyproline. Our hypothesis was generally supported in that postmenopausal white women did have less ALP, an indicator of bone deposition, than premenopausal women and postmenopausal African American women. Additional findings and directions for future studies are further discussed in this paper.

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Articular cartilage is a smooth, white connective tissue that covers and protects the ends of long bones to allow for a smooth, frictionless surface on which to glide for easy movement. Once the tissue is damaged, articular cartilage lacks a direct blood supply, which results in a limited ability to repair itself. This study explores the effect of the growth factor BMP-13 on the chondroinduction of primary human bone marrow-derived mesenchymal stem cells. The results demonstrate the limited ability of BMP-13 to exert a strong chondroinductive effect on human bone marrow-derived MSCs. However, the results do indicate that BMP-13 has the ability to sustain chondroinduction to a certain extent for up to 18 days following initiation by 3 days of exposure to TGF-β3. Results are encouraging for future work that involves growth factor influence on MSCs in articular cartilage tissue engineering.

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no / There is growing interest in the use of mesenchymal stem cells (MSC) for immune therapy. Clinical trials that use MSC for treatment of therapy resistant graft versus host disease, Crohn's disease and organ transplantation have initiated. Nevertheless, the immunomodulatory effects of MSC are only partly understood. Clinical trials that are supported by basic research will lead to better understanding of the potential of MSC for immunomodulatory applications and to optimization of such therapies. In this manuscript we review some recent literature on the mechanisms of immunomodulation by MSC in vitro and animal models, present new data on the secretion of pro-inflammatory and anti-inflammatory cytokines, chemokines and prostaglandins by MSC under resting and inflammatory conditions and discuss the hopes and expectations of MSC-based immune therapy.

The use of nanowires, nano and micro needles in biomedical applications has markedly increased in the past years, mainly due to attractive properties such as biocompatibility and simple fabrication. Specifically, these structures have shown promise in applications including cell separation, tumor cell capture, intracellular delivery, cell therapy, cancer treatment and as cell growth scaffolds. The work proposed here aims to study two platforms for different applications: a vertical magnetic nanowire array for mesenchymal stem cell differentiation and a micro needle platform for intracellular delivery. First, a thorough evaluation of the cytotoxicity of nanowires was done in order to understand how a biological system interacts with high aspect ratio structures. Nanowires were fabricated through pulsed electrodeposition and characterized by electron microscopy, vibrating sample magnetometry and energy dispersive X-ray spectroscopy. Studies of biocompatibility, cell death, cell membrane integrity, nanowire internalization and intracellular dissolution were all performed in order to characterize the cell response. Results showed a variable biocompatibility depending on nanowire concentration and incubation time, with cell death resulting from an apoptotic pathway arising after internalization. A vertical array of nanowires was then used as a scaffold for the differentiation of human mesenchymal stem cells. Using fluorescence and electron microscopy, the interactions between the dense array of nanowires and the cells were analyzed, as well as the biocompatibility of the array and its effects on cell differentiation. A magnetic field was additionally applied on the substrate to observe a possible differentiation. Stem cells grown on this scaffold showed a cytoskeleton and focal adhesion reorganization, and later expressed the osteogenic marker osteopontin. The application of a magnetic field counteracted this outcome. Lastly, a micro needle platform was fabricated through lithography and electrodeposition, characterized using the previously mentioned techniques and then evaluated as a vector for intracellular delivery. Fluorescence and electron microscopy imaging were first performed to assess the biocompatibility, cell spreading and the interface of the cells and the needles. Intracellular delivery of a fluorescent dye was achieved via inductive heating of the needles, with the results showing a dependency of delivery and cell survivability on the exposure time.

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Endotoxemia is a major cause of morbidity and mortality in horses. The presence of large amounts of circulating endotoxin inititates a number of cell signaling pathways leading to a systemic inflammatory response. Activation of these pathways causes the release of a number of pro- and anti-inflammatory mediators. An overwhelming release of these mediators leads to the development of clinical signs associated with endotoxemia. Treatment options are limited mostly to supportive care at this time. Mesenchymal stem cells (MSCs) have been shown to have anti-inflamamtory and immune modulatory effects that may have some benefit for the treatment of horses with endotoxemia. To evaluate the effect of equine MSCs on the response to endotoxin challenge, the study was performed on two different stem cell lines with peripheral blood mononuclear cells (PBMCs) used as controls. After stimulation with endotoxin, secretion of tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), interleukin-10 (IL-10), and interferon gamma (IFN-γ) were determined by ELISA. The immunogenic properties of MSCs were assessed with a one-way mixed lymphocyte reaction. In addition, the ability of MSCs to alter production of cytokines from stimulated PBMCs was assessed. TNF-α was not produced by MSCs when compared to PBMCs (p = < 0.001). There was no significant difference between MSCs and PBMCs in the production of IL-6. IL-10 production was significantly different (p = <0.001) at 6 and 12 hours with MSCs producing more than PBMCs in one stem cell line only. MSCs did not stimulate proliferation of PBMCs. Co-incubation of MSCs with PBMCs decreased the production of TNF-α in both stem cell lines although it was not statistically significant (p = 0.4 and 0.9) at either time point. IL-6 secretion was suppressed at twelve hours with co-incubation. IL-10 production was increased with co-incubation in one stem cell line. MSCs secrete soluble factors that can alter PBMC cytokine production and they do not appear to be immunostimulatory. These findings have potential implication for treatment of equine inflammatory conditions. / Master of Science