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Previously, we showed that extracellular matrices (ECMs), produced ex vivo by various types of stromal cells, direct bone marrow mesenchymal stem cells (BM-MSCs) in a tissue-specific manner and recapitulate physiologic changes characteristic of the aging microenvironment. In particular, BM-MSCs obtained from elderly donors and cultured on ECM produced by young BM stromal cells showed improved quantity, quality and osteogenic differentiation. In the present study, we searched for matrix components that are required for a functional BM-MSC niche by comparing ECMs produced by BM stromal cells from "young" (≤25 y/o) versus "elderly" (≥60 y/o) donors. With increasing donor age, ECM fibrillar organization and mechanical integrity deteriorated, along with the ability to promote BM-MSC proliferation and responsiveness to growth factors. Proteomic analyses revealed that the matricellular protein, Cyr61/CCN1, was present in young, but undetectable in elderly, BM-ECM. To assess the role of Cyr61 in the BM-MSC niche, we used genetic methods to down-regulate the incorporation of Cyr61 during production of young ECM and up-regulate its incorporation in elderly ECM. The results showed that Cyr61-depleted young ECM lost the ability to promote BM-MSC proliferation and growth factor responsiveness. However, up-regulating the incorporation of Cyr61 during synthesis of elderly ECM restored its ability to support BM-MSC responsiveness to osteogenic factors such as BMP-2 and IGF-1. We next examined aging bone and compared bone mineral density and Cyr61 content of L4-L5 vertebral bodies in "young" (9-11 m/o) and "elderly" (21-33 m/o) mice. Our analyses showed that low bone mineral density was associated with decreased amounts of Cyr61 in osseous tissue of elderly versus young mice. Our results strongly demonstrate a novel role for ECM-bound Cyr61 in the BM-MSC niche, where it is responsible for retention of BM-MSC proliferation and growth factor responsiveness, while depletion of Cyr61 from the BM niche contributes to an aging-related dysregulation of BM-MSCs. Our results also suggest new potential therapeutic targets for treating age-related bone loss by restoring specific ECM components to the stem cell niche.

The immature phenotype of human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs) is a major limitation to the use of these valuable cells for pre-clinical toxicity testing and for disease modeling. Here we tested the hypothesis that human perinatal stem cell derived extracellular matrix (ECM) promotes hiPSC-CM maturation to a greater extent than mouse cell derived ECM. We refer to the human ECM as Matrix Plus (Matrix Plus) and compare effects to commercially available mouse ECM (Matrigel). hiPSC-CMs cultured on Matrix Plus mature functionally and structurally seven days after thaw from cryopreservation. Mature hiPSC-CMs showed rod-shaped morphology, highly organized sarcomeres, elevated cTnI expression and mitochondrial distribution and function like adult cardiomyocytes. Matrix Plus also promoted mature hiPSC-CM electrophysiological function and monolayers’ response to hERG ion channel specific blocker was Torsades de Pointes (TdP) reentrant arrhythmia activations in 100% of tested monolayers. Importantly, Matrix Plus enabled high throughput cardiotoxicity screening using mature human cardiomyocytes with validation utilizing reference compounds recommended for the evolving Comprehensive In Vitro Proarrhythmia Assay (CiPA) coordinated by the Health and Environmental Sciences Institute (HESI). Matrix Plus offers a solution to the commonly encountered problem of hiPSC-CM immaturity that has hindered implementation of these human based cell assays for pre-clinical drug discovery.

Nerve tissue regeneration continues to represent an intractable obstacle to realizing the promise of tissue engineering. Although neurobiology works to shed light on the mechanisms governing neuronal growth and repair, considerable technical gaps remain that hinder progress. Chief among these is the absence of an appropriate culture environment to faithfully reproduce the neuronal niche ex vivo. We propose that the various multipotent cells found in the oral cavity may represent an important yet underutilized resource for preparing such neurogenic microenvironments. Similar to those of nerve tissue, these cell populations are of ectodermal origin and have clinically demonstrated neurogenic potential. Although there is a lack of consensus on whether putative types of oral and craniofacial stem cells constitute distinct populations, their contribution to neural tissue engineering may be twofold: as a cellular feedstock for neoneurogenesis and for the production of specialized in vitro environments for neurogenic differentiation, phenotype maintenance, and use in therapeutic applications. IMPACT STATEMENT: We propose that addressing gaps in understanding the neurogenic role of dental stem cells and their microenvironment may yield efficient and reliable strategies for long-term neuronal cell culture and open new avenues for neural regeneration in both dental, nerve, and other tissues.

As the global population ages, the prevalence of osteoarthritis (OA) and joint disorders represent a major cause of disability and a significant public health burden. As current approaches for the management of OA focus on slowing the progression of disease, without repairing the underlying damage, novel treatments are necessary to improve outcomes. Over the past decade, autologous cell-based therapies using regenerative cells from fat or bone marrow have become a major focus of research into new approaches for the treatment of osteoarthritis and joint disorders. This review is intended to summarize findings in existing literature and identify gaps in knowledge that should be addressed in order to advance the field. We acknowledge that some findings may appear inconsistent, but show that apparent inconsistency in the literature may be attributable to variation in source of cells, stage of disease, method of delivery, follow-up time, evaluation method, and a number of other idiosyncrasies of individual studies. Still, a number of themes emerge from the data and some broader conclusions may be drawn that can be used to guide future studies. Ultimately, we conclude that there is overwhelming evidence demonstrating the safety of the autologous cell-based therapies. Furthermore, the data support the claim that regenerative cells are capable of reversing progression of OA. Regenerative cells, and especially those from adipose tissue, represent a promising new approach for the treatment of OA. Future work should include appropriate controls, and focus on answering questions related to dose required, appropriate delivery vehicle, and the impact of multiple treatments. Additionally, future studies should look at short and long-term effects of the treatments, and use functional as well as radiologic methods to evaluate efficacy.

As an introduction to this book on stem cell therapies, this chapter presents the rationale for preparing this volume and describes its key features. A brief historical overview is presented, describing some useful observations from the past to provide context and help us to overcome some of the current obstacles toward clinical translation. We attempt to clarify some of the confusion regarding terminology in the field (e.g., the term “mesenchymal stem cells”), as well as raise some specific questions/issues that we believe have hindered efforts in achieving effective stem cell–based therapies. The hope is that this volume will foster more critical thinking and generate robust discussion among basic and social scientists and clinicians, which may help us identify new solutions for navigating the roadblocks that continue to impede the translation of MSC-based therapies to the clinic.

Autologous mesenchymal stem cell (MSC)–based therapies are preferable due to biosafety concerns. In addition, increasing evidence suggests that MSCs may not be immune privileged. However, the quantity and quality of MSCs decline with age and limit the effectiveness and regenerative potential of autologous MSC therapies in elderly patients. Interestingly, we have observed that a subpopulation of MSCs (5%–10% of the total population) from elderly donors possess a more “youthful” phenotype. The activity of these “youthful” cells in vivo may be deeply suppressed by the aging environment, and the viability of these cells is diminished by harmful factors released by neighboring senescent cells during expansion in culture. In this chapter, we discuss principles for the use of MSCs in antiaging, and specifically describe a novel strategy for isolating and expanding this “youthful” subpopulation from elderly patients to bank large quantities of high-quality autologous MSCs for treating age-related diseases.

Amyotrophic lateral sclerosis (ALS) is a progressive and fatal neurological disease characterized by degeneration and death of motor neurons. Aberrant protein aggregation and oxidative stress are implicated in the etiology of ALS; thus preventing propagation of early aggregation events and oxidative damage could be an effective therapy. We tested the effect of dietary supplementation (initiated 40 days of age) with 2-(2-hydroxyphenyl)-benzoxazole (HBX), a compound with metal chelator and anti-aggregation properties, on disease onset, progression and lifespan in the G93A mouse model of ALS. Tests were not sufficiently powerful to detect any change to survival distribution of mice treated with HBX. However, the disease onset was delayed and max lifespan was increased in the treatment group. Additionally, disease progression was moderated as shown by reduced neuromuscular denervation measured by repetitive nerve stimulation. F2-isoprostanes, a marker of oxidative damage, are elevated in skeletal muscle from G93A mice at onset and this increase is prevented in HBX fed G93A mice. Furthermore, HBX treatment reduced mutant SOD1 protein aggregation in whole spinal cord of G93A mice at disease onset. Overall, our data suggests that HBX may be able to improve the degenerative symptoms of ALS through the prevention of oxidative damage and protein aggregation. Further studies are needed to uncover the mechanistic effects of HBX in ameliorating ALS pathology.

Science outreach improves science literacy among the public and communication skills of scientists. However, despite the array of well-documented benefits, robust outreach efforts are often absent from communities which stand to benefit the most from these initiatives. Here, we introduce “Science Fiesta,” a graduate student-led outreach initiative which utilizes cultural traditions of South Texas as a vehicle to establish self-sustaining interactions between scientists and their local community. Event assessment surveys indicated that attendees found the event both fun and educational. At the same time, graduate students who organized the event and participated in outreach reported that they strengthened a variety of professional skills important for their future careers. More importantly, the event had a substantial positive impact on enthusiasm for science outreach. Both public attendees and graduate students reported that they were likely to participate in future science outreach events, even though a majority of both groups had not been previously involved in outreach efforts. Science Fiesta is a model for a highly effective graduate student-led outreach initiative that is capable of 1) improving public scientific literacy, 2) reinforcing graduate education and career development and 3) creating a culture of science engagement within local communities.

Background Umbilical cord blood (UCB) not only contains hematopoietic stem cells (HSCs), but also non-hematopoietic stem cells (NHSCs) that are able to differentiate into a number of distinct cell types. Based on studies published to date, the frequency of NHSCs in UCB is believed to be very low. However, the isolation of these cells is primarily based on their adhesion to tissue culture plastic surfaces. Methods and results In the current study, we demonstrate that this approach overlooks some of the extremely immature NHSCs because they lack the ability to adhere to plastic. Using a native extracellular matrix (ECM), produced by bone marrow (BM) stromal cells, the majority of the UCB-NHSCs attached within 4 h. The colony-forming unit fibroblast frequency of these cells was 1.5 × 104/108 mononuclear cells, which is at least 4000-fold greater than previously reported for UCB-NHSCs. The phenotype of these cells was fibroblast-like and different from those obtained by plastic adhesion; they formed embryonic body-like clusters that were OCT4-positive and expressed other human embryonic stem cell-related markers. Importantly, when implanted subcutaneously for 8 weeks into immunocompromised mice, these ECM-adherent and expanded NHSCs generated three germ layer-derived human tissues including muscle, fat, blood vessel, bone, gland, and nerve. Moreover, injection of these cells into muscle damaged by cryoinjury significantly accelerated muscle regeneration. Conclusions These results indicate that UCB may be a virtually unlimited source of NHSCs when combined with isolation and expansion on ECM. NHSCs may be a practical alternative to embryonic stem cells for a number of therapeutic applications.