Combination therapy along with mesenchymal stem cells in wound healing; the state of the art

Conditioned media of stem cells from human exfoliated deciduous teeth contain factors related to extracellular matrix organization and promotes corneal epithelial wound healing

This study aimed to investigate the therapeutic potential of cell-free conditioned media (CM) from human mesenchymal stem cells (hMSCs), specifically stem cells from human exfoliated deciduous teeth (SHED), for treating ocular surface diseases. The proteomes of various hMSC-CMs were compared using cytokine array and liquid chromatography-mass spectrometry (LC-MS). Bioinformatic analysis identified key biological pathways associated with SHED-CM, immortalized SHED-CM (IM-SHED-CM), and a fractionated component of IM-SHED-CM in which low weight molecules (less than 3.5kD) were depleted. Corneal epithelial wound healing models were constructed by epithelial scraping and treated with eye drops derived from SHED-CM. For the migration assay, the human corneal epithelial cells were wounded and then incubated with SHED-CM. SHED-CM, IM-SHED-CM, and >3.5 kD fractionated component eyedrops were administered to a chronic graft-versus-host disease (cGVHD) mouse model with sever corneal epithelial damages. SHED-CM, IM-SHED-CM, and >3.5 kD fractionated component of IM-SHED-CM were enriched in factors involved in epithelial wound healing, particularly extracellular matrix (ECM) organization. Both in vitro and in vivo assays demonstrated that SHED-CM significantly enhanced corneal epithelial wound healing. Furthermore, SHED-CM-derived eye drops reduced corneal epithelial damage, inflammatory cell infiltration, and oxidative stress in the corneal epithelium and maintained the expression of limbal stem cell markers in the cGVHD mouse model. These findings suggest that SHED-CM eye drops could be a novel treatment for corneal epithelial damage, highlighting the role of bioactive factors in promoting wound healing and offering an alternative to cell-based MSC therapies for corneal wound healing.

Application of Mesenchymal Stem Cells and Exosome alone or Combination Therapy as a Treatment Strategy for Wound Healing

The process of wound healing consists of multiple phases, and any disruptions in these phases can lead to the wound becoming chronic and impose heavy financial and psychological costs on the patient and a huge economic burden on the country's healthcare system. Various treatments such as drugs, matrix and scaffolds, blood products, cell therapy, and a combination of these treatments are used for wound healing. The use of mesenchymal stem cells (MSCs) is one of these methods that have produced appropriate responses in the healing of patients' wounds. MSCs by secreting growth factors, cytokines, chemokines, and RNAs elicit changes in cell proliferation, migration, growth, signaling, immunomodulation, and wound re-epithelialization process, and as a result, accelerate wound closure and wound healing. These cells can be isolated from different body sources with different cell characteristics and used directly on the wound site or by injection. In addition, MSCs-derived exosomes have attracted growing attention due to circumventing concerns relating to the direct use of MSCs. To increase the performance of MSCs, they can be used together with other compounds such as platelets, matrices, or scaffolds. This study examined the functions of MSCs in wound healing, as well as the vesicles they secrete, cellular and molecular mechanisms, and combined treatments with MSCs for wound healing.

Polysaccharide- and protein-based hydrogel dressings that enhance wound healing: A review

Hydrogels can possess desired biochemical and mechanical properties, excellent biocompatibility, satisfactory biodegradability, and biological capabilities that promote skin repair, making them ideal candidates for skin healing dressings. Polysaccharides, such as chitosan, hyaluronic acid and sodium alginate as well as proteins, including gelatin, collagen and fibroin proteins, are biological macromolecules celebrated for their biocompatibility and biodegradability, are at the forefront of innovative hydrogel dressing development. This work first summarizes the skin wound healing process and its influencing factors, and then systematically articulates the multifunctional roles of hydrogels based on biological macromolecules (polysaccharides and proteins) as dressing in addressing bacterial infection, hemorrhage and inflammation during wound healing. Furthermore, this review explores the potential of these hydrogels as vehicles for combination therapy, by incorporating growth factors or stem cells. Finally, the article offers insights into future directions of such hydrogels in wound repair field.

Cellular Components of the Blood-Brain Barrier and Their Involvement in Aging-Associated Cognitive Impairment

Human life expectancy has been significantly extended, which poses major challenges to our healthcare and social systems. Aging-associated cognitive impairment is attributed to endothelial dysfunction in the cardiovascular system and neurological dysfunction in the central nervous system. The central nervous system is considered an immune-privileged tissue due to the exquisite protection provided by the blood-brain barrier. The present review provides an overview of the structure and function of blood-brain barrier, extending the cell components of blood-brain barrier from endothelial cells and pericytes to astrocytes, perivascular macrophages and oligodendrocyte progenitor cells. In particular, the pathological changes in the blood-brain barrier in aging, with special focus on the underlying mechanisms and molecular changes, are presented. Furthermore, the potential preventive/therapeutic strategies against aging-associated blood-brain barrier disruption are discussed.

Human Mesenchymal Stem Cells on Size-Sorted Gelatin Hydrogel Microparticles Show Enhanced In Vitro Wound Healing Activities

The demand for innovative therapeutic interventions to expedite wound healing, particularly in vulnerable populations such as aging and diabetic patients, has prompted the exploration of novel strategies. Mesenchymal stem cell (MSC)-based therapy emerges as a promising avenue for treating acute and chronic wounds. However, its clinical application faces persistent challenges, notably the low survivability and limited retention time of engraftment in wound environments. Addressing this, a strategy to sustain the viability and functionality of human MSCs (hMSCs) in a graft-able format has been identified as crucial for advanced wound care. Hydrogel microparticles (HMPs) emerge as promising entities in the field of wound healing, showcasing versatile capabilities in delivering both cells and bioactive molecules/drugs. In this study, gelatin HMPs (GelMPs) were synthesized via an optimized mild processing method. GelMPs with distinct diameter sizes were sorted and characterized. The growth of hMSCs on GelMPs with various sizes was evaluated. The release of wound healing promoting factors from hMSCs cultured on different GelMPs were assessed using scratch wound assays and gene expression analysis. GelMPs with a size smaller than 100 microns supported better cell growth and cell migration compared to larger sizes (100 microns or 200 microns). While encapsulation of hMSCs in hydrogels has been a common route for delivering viable hMSCs, we hypothesized that hMSCs cultured on GelMPs are more robust than those encapsulated in hydrogels. To test this hypothesis, hMSCs were cultured on GelMPs or in the cross-linked methacrylated gelatin hydrogel (GelMA). Comparative analysis of growth and wound healing effects revealed that hMSCs cultured on GelMPs exhibited higher viability and released more wound healing activities in vitro. This observation highlights the potential of GelMPs, especially those with a size smaller than 100 microns, as a promising carrier for delivering hMSCs in wound healing applications, providing valuable insights for the optimization of advanced therapeutic strategies.

Platelet Concentrates Preconditioning of Mesenchymal Stem Cells and Combined Therapies: Integrating Regenerative Strategies for Enhanced Clinical Applications

This article presents a comprehensive review of the factors influencing the efficacy of mesenchymal stem cells (MSCs) transplantation and its association with platelet concentrates (PCs). It focuses on investigating the impact of PCs' composition, the age and health status of platelet donors, application methods, and environmental factors on the outcomes of relevant treatments. In addition, it delves into the strategies and mechanisms for optimizing MSCs transplantation with PCs, encompassing preconditioning and combined therapies. Furthermore, it provides an in-depth exploration of the signaling pathways and proteomic characteristics associated with preconditioning and emphasizes the efficacy and specific effects of combined therapy. The article also introduces the latest advancements in the application of biomaterials for optimizing regenerative medical strategies, stimulating scholarly discourse on this subject. Through this comprehensive review, the primary goal is to facilitate a more profound comprehension of the factors influencing treatment outcomes, as well as the strategies and mechanisms for optimizing MSCs transplantation and the application of biomaterials in regenerative medicine, offering theoretical guidance and practical references for related research and clinical practice.