Efficacy Of MSC-based Therapies Research Articles

Isolation and Characterization of Bacterial Contaminants from Bone Marrow-Derived Mesenchymal Stem Cell Cultures

This study aimed to assess and manage bacterial contamination in multiple batches of mesenchymal stem cell (MSC) cultures derived from rabbit bone marrow. Routine visual inspection and microscopic examination were employed for the detection of the contaminated cultures. The contaminated cultures were inoculated on Nutrient agar and multiple isolated colonies were subjected to Gram staining and biochemical characterization. Further, molecular identification of the bacterial isolates was performed using polymerase chain reaction. The determination of antibiotic susceptibility patterns was conducted using the Kirby-Bauer disc diffusion method. Among the 351 mesenchymal stem cell culture (SCC) flasks monitored, only 1.42% were found to be contaminated. Based on the phenotypic and biochemical characterization, the major bacterial contaminants were identified as Staphylococcus aureus, Bacillus spp., and Escherichia coli infiltrating during various stages of cell processing. Antibiotic susceptibility patterns revealed varying responses among isolates, crucial for effective antimicrobial strategies and maintaining aseptic conditions in SCCs. The study emphasizes the importance of regular monitoring to maintain sterile environments, validate culture quality, and uphold safety standards. The findings indicate the need to establish stringent quality control measures, crucial for the successful translation of MSC research into clinical applications. The research advocates for continuous monitoring, adherence to SOPs, and further investigations into preventive strategies for ensuring the safety and efficacy of MSC-based therapies.

Glucose Metabolism: Optimizing Regenerative Functionalities of Mesenchymal Stromal Cells Postimplantation.

Mesenchymal stromal cells (MSCs) are considered promising candidates for regenerative medicine applications. Their clinical performance postimplantation, however, has been disappointing. This lack of therapeutic efficacy is most likely due to suboptimal formulations of MSC-containing material constructs. Tissue engineers, therefore, have developed strategies addressing/incorporating optimized cell, microenvironmental, biochemical, and biophysical cues/stimuli to enhance MSC-containing construct performance. Such approaches have had limited success because they overlooked that maintenance of MSC viability after implantation for a sufficient time is necessary for MSCs to develop their regenerative functionalities fully. Following a brief overview of glucose metabolism and regulation in MSCs, the present literature review includes recent pertinent findings that challenge old paradigms and notions. We hereby report that glucose is the primary energy substrate for MSCs, provides precursors for biomass generation, and regulates MSC functions, including proliferation and immunosuppressive properties. More importantly, glucose metabolism is central in controlling in vitro MSC expansion, in vivo MSC viability, and MSC-mediated angiogenesis postimplantation when addressing MSC-based therapies. Meanwhile, in silico models are highlighted for predicting the glucose needs of MSCs in specific regenerative medicine settings, which will eventually enable tissue engineers to design viable and potent tissue constructs. This new knowledge should be incorporated into developing novel effective MSC-based therapies. Impact statement The clinical use of mesenchymal stromal cells (MSCs) has been unsatisfactory due to the inability of MSCs to survive and be functional after implantation for sufficient periods to mediate directly or indirectly a successful regenerative tissue response. The present review summarizes the endeavors in the past, but, most importantly, reports the latest findings that elucidate underlying mechanisms and identify glucose metabolism as the crucial parameter in MSC survival and the subsequent functions pertinent to new tissue formation of importance in tissue regeneration applications. These latest findings justify further basic research and the impetus for developing new strategies to improve the modalities and efficacy of MSC-based therapies.

The Dynamic Roles of Mesenchymal Stem Cells in Colon Cancer.

Colon cancer is still one of the most common causes of cancer in human and is characterized by lymphocyte infiltrates and originates from the epithelial cells found in the lining of colon or rectum of the gastrointestinal tract. Mesenchymal stem cells (MSCs) are composed of the multipotent stem cell group of stroma and can be differentiated as various cell lineages, such as fibroblasts, osteoblasts, and adipocytes. MSCs provide mechanical and structural support and have potential functions during tumor growth and metastasis. The efficacy of MSC-based therapies is partly dependent on the migration and homing of MSCs to tumors and metastatic sites. However, their migratory and engraftment potential is poorly understood. In this review, the characteristics and mechanisms of MSC's dynamic interaction with colon cancer were summarized, particularly the potential functions of MSCs on colon cancer, including its role in improving tumor growth and as a potential candidate for tumor therapy. Understanding MSC homing provides new insights into the manipulation of MSC and the improvement of their efficacy for colon cancer therapy.

Deterministic and stochastic approaches in the clinical application of mesenchymal stromal cells (MSCs).

Mesenchymal stromal cells (MSCs) have enormous intrinsic clinical value due to their multi-lineage differentiation capacity, support of hemopoiesis, immunoregulation and growth factors/cytokines secretion. MSCs have thus been the object of extensive research for decades. After completion of many pre-clinical and clinical trials, MSC-based therapy is now facing a challenging phase. Several clinical trials have reported moderate, non-durable benefits, which caused initial enthusiasm to wane, and indicated an urgent need to optimize the efficacy of therapeutic, platform-enhancing MSC-based treatment. Recent investigations suggest the presence of multiple in vivo MSC ancestors in a wide range of tissues, which contribute to the heterogeneity of the starting material for the expansion of MSCs. This variability in the MSC culture-initiating cell population, together with the different types of enrichment/isolation and cultivation protocols applied, are hampering progress in the definition of MSC-based therapies. International regulatory statements require a precise risk/benefit analysis, ensuring the safety and efficacy of treatments. GMP validation allows for quality certification, but the prediction of a clinical outcome after MSC-based therapy is correlated not only to the possible morbidity derived by cell production process, but also to the biology of the MSCs themselves, which is highly sensible to unpredictable fluctuation of isolating and culture conditions. Risk exposure and efficacy of MSC-based therapies should be evaluated by pre-clinical studies, but the batch-to-batch variability of the final medicinal product could significantly limit the predictability of these studies. The future success of MSC-based therapies could lie not only in rational optimization of therapeutic strategies, but also in a stochastic approach during the assessment of benefit and risk factors.

Mesenchymal stem cell biodistribution, migration, and homing in vivo.

Mesenchymal stem cells (MSCs) were originally defined by their capacity to differentiate into various connective tissue lineages as well as support hematopoiesis in vitro via the production of various cytokines, chemokines, and adhesion molecules [1, 2]. During the past decade, MSCs have been shown to exhibit angiogenic, trophic, anti-inflammatory, and immunomodulatory activity using a variety of experimental paradigms [3–6]. Together with their easy availability and amenability to large-scale expansion ex vivo, these properties have propelled MSC-based therapies to the forefront of regenerative medicine and immune regulatory cell therapy. Currently, MSCs from a variety of tissue sources are being evaluated in over 200 clinical trials for the treatment of a diverse array of disease indications. Completed Phase I and II clinical trials have reported statistically significant benefits in patients with steroid-resistant graft versus host disease [7], severe systemic lupus erythematosus [8], complex perianal fistulas [9], and ischemic cardiomyopathy [10]. However, not all trials have met their primary endpoint of efficacy and while many factors contribute to suboptimal patient outcomes, key among them are the molecular mechanisms that govern MSC engraftment, homing, and biodistribution in vivo. Indeed, despite rapid progress in describing the therapeutic potency of MSCs in experimental animal models of disease, progress in understanding their biodistribution and mechanism of action in vivo has been slow to develop. For example, robust methodologies to track the fate of MSCs in vivo are critical toward establishing their tissue tropism, duration of engraftment, and rates of clearance. In addition, the identification of endogenous factors that function as chemoattractants and repellents also plays critical roles in directing transplanted cells to sites of tissue injury. Moreover, a clearer understanding of the signaling axes that regulate MSC trafficking in vivo would provide a means to direct cells to specific tissue and organs, thereby increasing overall efficacy of MSC-based therapies. The latter may also provide a means to mobilize endogenous MSCs and enhance their regenerative and immune regulatory properties. Finally, cellular crosstalk and cell-to-cell interactions also likely affect the biodistribution and survival of exogenously administered MSCs, but scant information exists regarding these processes in vivo. In fact, it is a subject of debate whether MSCs localize to tissue due to passive entrapment in small vessels, particularly in lung, or if cells employ active mechanisms similar to leukocytes to home to specific tissues. Therefore, continued study into the mechanism that regulates trafficking of endogenous and transplanted MSCs will shed novel insight into basic MSC biology and lead to the development of more potent cell-based therapies.