Heat shock attenuates VEGF expression in three-dimensional myoblast sheets deteriorating therapeutic efficacy in heart failure

Concise Review: Optimized Strategies for Stem Cell-Based Therapy in Myocardial Repair: Clinical Translatability and Potential Limitation

Ischemic heart diseases (IHDs) remain major public health problems with high rates of morbidity and mortality worldwide. Despite significant advances, current therapeutic approaches are unable to rescue the extensive and irreversible loss of cardiomyocytes caused by severe ischemia. Over the past 16 years, stem cell-based therapy has been recognized as an innovative strategy for cardiac repair/regeneration and functional recovery after IHDs. Although substantial preclinical animal studies using a variety of stem/progenitor cells have shown promising results, there is a tremendous degree of skepticism in the clinical community as many stem cell trials do not confer any beneficial effects. How to accelerate stem cell-based therapy toward successful clinical application attracts considerate attention. However, many important issues need to be fully addressed. In this Review, we have described and compared the effects of different types of stem cells with their dose, delivery routes, and timing that have been routinely tested in recent preclinical and clinical findings. We have also discussed the potential mechanisms of action of stem cells, and explored the role and underlying regulatory components of stem cell-derived secretomes/exosomes in myocardial repair. Furthermore, we have critically reviewed the different strategies for optimizing both donor stem cells and the target cardiac microenvironments to enhance the engraftment and efficacy of stem cells, highlighting their clinical translatability and potential limitation. Stem Cells 2018;36:482-500.

Factors influencing yield and neuronal differentiation of mesenchymal stem cells from umbilical cord blood and matrix

Aim: Umbilical cord blood and Wharton's jelly (WJ) are potential sources of mesenchymal stem cells (MSCs). We investigated whether harvesting and donor characteristics affected yield and neuronal differentiation, and compared human umbilical cord blood (hUCB) and WJ-derived MSCs regarding neuronal differentiation and cytokine secretion. Materials & methods: MSCs were analyzed by immunoblotting after seven days of differentiation; cytokine protein arrays were used to analyze conditioned medium. Results: Birth weight and blood/anticoagulant ratio influenced MSC yield per unit blood volume, but not maternal and gestational age, delivery mode or fetal gender. Expression of the early neuronal differentiation marker nestin was unaffected by these variables. hUCB- and WJ-derived MSC secrete distinct cytokine profiles. Conclusion: Cell yield is affected by certain donor characteristics. hUCB- and WJ-derived MSCs may serve distinct therapeutic niches.

Thymosin β4 has a major role in dermal burn wound healing that involves actin cytoskeletal remodelling via heat-shock protein 70

Rapid vascular remodelling of damaged dermal tissue is required to heal burn wounds. Thymosin β4 (Tβ4) is a growth factor that has been shown to promote angiogenesis and dermal wound repair. However, the underlying mechanisms based on Tβ4 function have not yet been fully investigated. In the present study, we investigated how Tβ4 improves dermal burn wound healing via actin cytoskeletal remodelling and the action of heat-shock proteins (HSPs), which are a vital set of chaperone proteins that respond to heat shock. Our in vitro results achieved with the use of human umbilical vein endothelial cells (HUVECs) revealed a possible signal between Tβ4 and HSP70. Moreover, we confirmed that remodelling of filamentous actin (F-actin) was regulated by Tβ4-induced HSP70 in HUVECs. Based on these in vitro results, we confirmed the healing effects of Tβ4 in an adapted dermal burn wound in vivo model. Tβ4 improved wound-healing markers, such as wound closure and vascularization. Moreover, Tβ4 maintained the long-term expression of HSP70, which is associated with F-actin regulation during the wound-healing period. These results suggest that an association between Tβ4 and HSP70 is responsible for the healing of burn wounds, and that this association may regulate F-actin remodelling. Copyright © 2015 John Wiley & Sons, Ltd.