Molecular hydrogen promotes wound healing by inducing early epidermal stem cell proliferation and extracellular matrix deposition

Key events relating to homeostasis and regeneration of freshwater planarians (Dugesia Japonica) after exposure to various ZnO-forms

This study aims to investigate the toxicity and underlying mechanisms of ZnO nanoparticles (ZnO NPs), bulk ZnO (ZnO MPs), and zinc ions (Zn2 +) on Dugesia japonica planarians, with a focus on their bioaccumulation, transformation, and associated biological effects. Using advanced techniques such as synchrotron X-ray fluorescence (XRF), X-ray Absorption Near Edge Structure (XANES) and single particle ICP-MS (sp-ICP-MS), we measured the accumulation, distribution, and transformation of these materials in planarians. All treatments caused significant Zn accumulation: ZnO NPs increased Zn by 120-fold, ZnO MPs by 100-fold, and Zn2+ by 430-fold. XANES and sp-ICP-MS analysis confirmed that ZnO NPs remained largely in particulate form (40-60 %) following uptake by planarians. Toxicity tests revealed that all treatments impaired blastema growth, locomotion, stem cell proliferation, differentiation, and neural regeneration. ZnO MPs exhibited higher toxicity than ZnO NPs, while Zn2+ resulted in elevated oxidative stress. ZnO NPs induced severe energy damage and triggered cell apoptosis, whereas ZnO MPs caused more pronounced necrosis cell death. Transcriptomic and proteomic analyses showed that all treatments disrupted pathways related to oxidative stress response, energy metabolism and cell apoptosis. ZnO NPs primarily affected the membrane integrity pathway, ZnO MPs altered cell homeostasis and membrane potential, while Zn2+ exposure triggered metal ion-specific cellular reactions. These molecular and cellular changes collectively explain the observed phenotypic outcomes, which align with the Adverse Outcome Pathway framework. The findings provide insights into the environmental risks of different ZnO forms and highlight their distinct toxicity mechanisms.

Degradation products of magnesium implant synergistically enhance bone regeneration: Unraveling the roles of hydrogen gas and alkaline environment

Biodegradable magnesium (Mg) implant generally provides temporary fracture fixation and facilitates bone regeneration. However, the exact effects of generated Mg ions (Mg2+), hydrogen gas (H2), and hydroxide ions (OH-) by Mg degradation on enhancing fracture healing are not fully understood. Here we investigate the in vivo degradation of Mg intramedullary nail (Mg-IMN), revealing the generation of these degradation products around the fracture site during early stages. Bulk-RNA seq indicates that H2 and alkaline pH increase periosteal cell proliferation, while Mg2+ may mainly enhance extracellular matrix formation and cell adhesion in the femur ex vivo. In vivo studies further reveal that H2, Mg2+ and alkaline pH individually generate comparable effects to the enhanced bone regeneration in the Mg-IMN group. Mechanistically, the degradation products elevate sensory calcitonin gene-related peptide (CGRP) and simultaneously suppress adrenergic factors in newly formed bone. H2 and Mg2+, instead of alkaline pH, increase CGRP synthesis and inhibit adrenergic receptors. Our findings, for the first time, elucidate that Mg2+, H2, and alkaline pH environment generated by Mg-IMN act distinctly and synergistically mediated by the skeletal interoceptive regulation to accelerate bone regeneration. These findings may advance the understanding on biological functions of Mg-IMN in fracture repair and even other bone disorders.

Hydrogen-Releasing Micromaterial Dressings: Promoting Wound Healing by Modulating Extracellular Matrix Accumulation Through Wnt/β-Catenin and TGF-β/Smad Pathways

Background: Wound healing is a complex and intricate biological process that involves multiple systems within the body and initiates a series of highly coordinated responses to repair damage and restore integrity and functionality. We previously identified that breathing hydrogen can significantly inhibit early inflammation, activate autologous stem cells, and promote the accumulation of extracellular matrix (ECM). However, the broader functions and downstream targets of hydrogen-induced ECM accumulation and tissue remodeling are unknown in the wound-healing process. Methods: Consequently, this thesis developed a hydrogen sustained-release dressing based on a micro storage material and reveals the mechanism of hydrogen in treating wound healing. Upon encapsulating the hydrogen storage materials, magnesium (Mg), and ammonia borane (AB), we found that SiO2@Mg exhibits superior sustained-release performance, while SiO2@AB demonstrates a higher hydrogen storage capacity. We used a C57/BL6 mouse full-thickness skin defect wound model to analyze and compare different hydrogen dressings. Results: It was identified that hydrogen dressings can significantly improve the healing rate of wounds by promoting epithelialization, angiogenesis, and collagen accumulation in wound tissue, and that the effect of slow-release dressings is better than of non-slow-release dressings. We also found that hydrogen dressing can promote transcriptome-level expression related to cell proliferation and differentiation and ECM accumulation, mainly through the Wnt1/β-catenin pathway and TGF-β1/Smad2 pathway. Conclusions: Overall, these results provide a novel insight into the field of hydrogen treatment and wound healing.

Application trends of hydrogen-generating nanomaterials for the treatment of ROS-related diseases

Reactive oxygen species (ROS) play essential roles in both physiological and pathological processes. Under physiological conditions, appropriate amounts of ROS play an important role in signaling and regulation in cells. However, too much ROS can lead to many health problems, including inflammation, cancer, delayed wound healing, neurodegenerative diseases (such as Parkinson's disease and Alzheimer's disease), and autoimmune diseases, and oxidative stress from excess ROS is also one of the most critical factors in the pathogenesis of cardiovascular and metabolic diseases such as atherosclerosis. Hydrogen gas effectively removes ROS from the body due to its good antioxidant properties, and hydrogen therapy has become a promising gas therapy strategy due to its inherent safety and stability. The combination of nanomaterials can achieve targeted delivery and effective accumulation of hydrogen, and has some ameliorating effects on diseases. Herein, we summarize the use of hydrogen-producing nanomaterials for the treatment of ROS-related diseases and talk about the prospects for the treatment of other ROS-induced disease models, such as acute kidney injury.

Hydrogen-Rich Saline Combined With Vacuum Sealing Drainage Promotes Wound Healing by Altering Biotin Metabolism

Impaired wound healing affects the life quality of patients and causes a substantial financial burden. Hydrogen-rich medium is reported to have antioxidant and anti-inflammatory effects. However, the role of hydrogen-rich saline (HRS) in cutaneous wound healing remains largely unexplored, especially by metabolomics. Thus, untargeted metabolomics profiling was analysed to study the effects and mechanism of HRS combined with vacuum sealing drainage (VSD) in a rabbit full-thickness wound model. Our results indicated that the combination treatment of HRS and VSD could accelerate wound healing. In vitro experiments further confirmed its effects on HaCaT keratinocytes. We found that 45 metabolites were significantly changed between the VSD + HRS group and the VSD + saline-treated group. Pathway enrichment analysis indicated that biotin metabolism was the potential target pathway. The biochemical interpretation analysis demonstrated that combining HRS and VSD might enhance mitochondrial function, ATP synthesis, and GSH homeostasis by altering biotin metabolism. The detection of representative indicators of oxidative stress supported the critical metabolic pathway analysis as well. In summary, VSD combined with HRS might provide a new strategy to enhance wound healing.

Extracellular Vesicles from Mesenchymal Stem Cells: Potential as Therapeutics in Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)

Background/Objectives: Metabolic dysfunction-associated steatotic liver disease (MASLD) is characterized by the accumulation of triglycerides within hepatocytes, which can progress to more severe conditions, such as metabolic dysfunction-associated steatohepatitis (MASH), which may include progressive fibrosis, leading to cirrhosis, cancer, and death. This goal of this review is to highlight recent research showing the potential of mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) in reducing the key pathogenic pathways of MASLD or MASH. Methods: Relevant published studies were identified using PubMed with one or more of the following search terms: MASLD, MASH, NAFLD, NASH, exosome, extracellular vesicle (EV), therapy, and/or mesenchymal stem cells (MSC). The primary literature were subsequently downloaded and summarized. Results: Using in vitro or in vivo models, MSC-EVs have been found to counteract oxidative stress, a significant contributor to liver injury in MASH, and to suppress disease progression, including steatosis, inflammation, and, in a few instances, fibrosis. Some of these outcomes have been attributed to specific EV cargo components including microRNAs and proteins. Thus, MSC-EVs enriched with these types of molecules may have improved the therapeutic efficacy for MASLD/MASH and represent a novel approach to potentially halt or reverse the disease process. Conclusions: MSC-EVs are attractive therapeutic agents for treating MASLD/MASH. Further studies are necessary to validate the clinical applicability and efficacy of MSC-EVs in human MASH patients, focusing on optimizing delivery strategies and identifying the pathogenic pathways that are targeted by specific EV components.

Exosome-based cell therapy for diabetic foot ulcers: Present and prospect

Diabetic foot ulcers (DFUs) represent a serious complication of diabetes with high incidence, requiring intensive treatment, prolonged hospitalization, and high costs. It poses a severe threat to the patient's life, resulting in substantial burdens on patient and healthcare system. However, the therapy of DFUs remains challenging. Therefore, exploring cell-free therapies for DFUs is both critical and urgent. Exosomes, as crucial mediators of intercellular communication, have been demonstrated potentially effective in anti-inflammation, angiogenesis, cell proliferation and migration, and collagen deposition. These functions have been proven beneficial in all stages of diabetic wound healing. This review aims to summarize the role and mechanisms of exosomes from diverse cellular sources in diabetic wound healing research. In addition, we elaborate on the challenges for clinical application, discuss the advantages of membrane vesicles as exosome mimics in wound healing, and present the therapeutic potential of exosomes and their mimetic vesicles for future clinical applications.

Clinical Observation of Hydrogen-Rich Saline for Nasal Irrigation After Surgery for Chronic sinusitis:A Randomized, Double-Blind, Controlled Trial

Purpose

The treatment of chronic rhinosinusitis (CRS) is often a difficult and long-term behavior, so it is necessary to seek a local treatment method that can be used for a long time, and is safe and effective. Nasal saline irrigation after functional endoscopic sinus surgery (FESS) is currently recognized as a local treatment method, but it has no anti-inflammatory, anti-damage, and healing-promoting functions. To investigate the efficacy and safety of hydrogen-rich saline (HRS) for nasal irrigation after CRS surgery.

Patients and Methods

A total of 61 patients after CRS completed the study. Subjects were randomly assigned to rinse the nasal cavity with HRS or normal saline (NS) after CRS. Participants were followed up once a week for 12 times, and were evaluated with visual analogue score (VAS), 22-item Sinonasal Outcomes Test (SNOT-22), and Lund-Kennedy endoscopy scores (LKES). The primary outcome was the VAS score of patients.

Results

After 12 weeks of follow-up, the VAS scores of both groups decreased, and the HRS group (0.52±0.85) was lower than the NS group (1.47±1.55), P=0.005. The total number of cases with complete control (clinical cure) in the short-term efficacy evaluation was more in the HRS group (20/31) than in the NS group (11/30), P=0.03<0.05. No obvious adverse reactions occurred in the two groups during the follow-up.

Conclusion

This study found that HRS was more effective than NS alone in nasal irrigation after CRS surgery, and could shorten the time of nasal mucosal healing and epithelialization, with a higher rate of recent complete control.

Epidermal stem cells: skin surveillance and clinical perspective

The skin epidermis is continually influenced by a myriad of internal and external elements. At its basal layer reside epidermal stem cells, which fuels epidermal renovation and hair regeneration with powerful self-renewal ability, as well as keeping diverse signals that direct their activity under surveillance with quick response. The importance of epidermal stem cells in wound healing and immune-related skin conditions has been increasingly recognized, and their potential for clinical applications is attracting attention. In this review, we delve into recent advancements and the various physiological and psychological factors that govern distinct epidermal stem cell populations, including psychological stress, mechanical forces, chronic aging, and circadian rhythm, as well as providing an overview of current methodological approaches. Furthermore, we discuss the pathogenic role of epidermal stem cells in immune-related skin disorders and their potential clinical applications.

Application of Non-Pharmacologic Therapy in Hair Loss Treatment and Hair Regrowth

Purpose

Alopecia significantly affects the appearance and psychology of patients, and pharmacological therapies and hair transplantation are the main treatments for alopecia, but both have limitations. This review aimed to summarize the non-pharmacological therapies that promote hair growth and regeneration.

Patients and Methods

This is a non-systematic review. Multiple databases was searched with relevant data published between 1997 and 2024. Searching and screening followed the PRISMA guidelines.

Results

Novel therapeutic modalities, such as gas molecules, platelet-rich plasma, laser, and microneedling, can change the microenvironment of hair follicles, activate hair follicle stem cells, and promote hair growth and regeneration.

Conclusion

This paper reviews research on the application of non-pharmacological therapies in alopecia treatment and hair regeneration, with a view to providing an important basis for future research on alopecia treatment and the postoperative treatment of patients after hair transplantation.

Poly(ionic liquid)-Flocculated Chlorella Loading Bactericidal and Antioxidant Hydrogel as a Biological Hydrogen Therapy for Diabetic Wound Dressing

Infection and oxidative stress seriously hinder the healing of diabetic wounds, resulting in various serious health and clinical problems. Herein, a sustainable biological hydrogen (H2)-producing hyaluronic acid-based hydrogel patch (HAP-Chl) was constructed by loading an imidazolium-based poly(ionic liquid) (PIL) flocculated live Chlorella as a diabetic wound dressing. The PIL can flocculate Chlorella through electrostatic interactions between PIL and Chlorella to form Chlorella agglomerates, endowing the Chlorella in the central agglomerates with the ability to continuously produce H2 for 24 h under mild conditions. Combining the membrane disruption-related bactericidal mechanism of PIL and the antioxidant properties of the produced H2, HAP-Chl was determined to be antibacterial and antioxidant. In addition to exhibiting biocompatible and nontoxic activities, subsequent Staphylococcus aureus-infected chronic wound studies revealed that HAP-Chl is capable of promoting the healing of chronic wounds by effectively killing bacteria, reducing extensive ROS, relieving inflammation, and promoting the deposition of mature collagen and angiogenesis. This study provides a new strategy for constructing an in situ sustainable H2-producing hydrogel, enabling the formation of novel antibacterial and antioxidant material platforms with potential for wound dressing applications.

Hydrogen gas improves proliferation and mitochondrial activity of human adipose-derived stem cells after cryopreservation

The objective of this study is to evaluate the effect of hydrogen gas on the biological functions of human adipose-derived stem cells (hADSC) in cryopreservation. hADSC were cryopreserved by a commercial cell preservation solution in the presence of hydrogen gas. After cryopreservation at -80 °C, the viability, initial attachment morphology, and biological parameters of cells cryopreserved were evaluated to compare with those of cells cryopreserved in the absence of hydrogen gas. The hydrogen concentration in the cell preservation solution was 2.0 ppm immediately after preparation and after that decreased with time. The presence of hydrogen gas permitted cells to significantly increase the proliferation of cells in addition to the percent initial adhesion. The number of cells in the spread state was significantly high compared with that of hydrogen gas-free cryopreserved cells. The cell cycle measurement with the flow cytometry and measurement of intracellular reactive oxygen species (ROS) were performed to demonstrate an enhanced cell cycle and a decreased ROS production. In the cell cycle assay, the percentage of cells in the mitotic phase increased. The presence of hydrogen gas decreased hydroxyl radicals immediately to a significantly great extent after thawing. It is concluded that the presence of hydrogen gas during cryopreservation is promising to improve the biological behavior of cells after cell thawing in terms of cells viability, proliferation or metabolic activity.

Influence of Different Photobiomodulation Parameters on Multi-Potent Adipose Tissue Mesenchymal Cells In Vitro

Objective: Investigating the effect of different parameters of photobiomodulation (PBM) with low-power laser on multi-potent mesenchymal stem cells (MSCs) derived from adipose tissue in terms of proliferation and cell death. Methods: MSCs were submitted to PBM applications with combinations of the following physical parameters: control group (no intervention), wavelengths of 660 and 830 nm; energy of 0.5, 2, and 4 J; and power of 40 and 100 mW. MSC analysis was performed using MetaXpress® software at 24, 48, and 72 h. Results: Irradiation promoted a significant increase in cell proliferation (p < 0.05), with 830 nm laser, 100 mW, with energy of 0.5, 2, and 4 J in relation to the control group at all times. PBM with 660 nm, power of 40 mW, and energy of 0.5, 2, and 4 J produced greater cell death at 24 h compared with the control group. At the time of 72 h, there was no significant difference concerning cell death. Conclusions: According to the results found, we can conclude that both wavelengths were effective; however, the 830 nm laser was more effective in terms of cell proliferation compared with the 660 nm laser. The 660 nm wavelength showed a significant increase in cell death when compared with the 830 nm laser.

Photobiomodulation Facilitates Rat Cutaneous Wound Healing by Promoting Epidermal Stem Cells and Hair Follicle Stem Cells Proliferation

BACKGROUND

Cutaneous wound healing represents a common fundamental phenomenon requiring the participation of cells of distinct types and a major concern for the public. Evidence has confirmed that photobiomodulation (PBM) using near-infrared (NIR) can promote wound healing, but the  cells involved and the precise molecular mechanisms remain elusive.

METHODS

Full-thickness skin defects with a diameter of 1.0 cm were made on the back of rats and randomly divided into the control group, 10 J, 15 J, and 30 J groups. The wound healing rate at days 4, 8, and 12 postoperatively was measured. HE and Masson staining was conducted to reveal the histological characteristics. Immunofluorescence staining was performed to label the epidermal stem cells (ESCs) and hair follicle stem cells (HFSCs). Western blot was performed to detect the expressions of proteins associated with ESCs and HFSCs. Cutaneous wound tissues were collected for RNA sequencing. Gene ontology and the Kyoto Encyclopedia of Genes and Genomes analysis was performed, and the hub genes were identified using CytoHubba and validated by qRT-PCR.

RESULTS

PBM can promote reepithelialization, extracellular matrix deposition, and wound healing, increase the number of KRT14+/PCNA+ ESCs and KRT15+/PCNA+ HFSCs, and upregulate the protein expression of P63, Krt14, and PCNA. Three hundred and sixty-six differentially expressed genes (DEGs) and 7 hub genes including Sox9, Krt5, Epcam, Cdh1, Cdh3, Dsp, and Pkp3 were identified. These DEGs are enriched in skin development, cell junction, and cadherin binding involved in cell-cell adhesion etc., while these hub genes are related to skin derived stem cells and cell adhesion.

CONCLUSION

PBM accelerates wound healing by enhancing reepithelialization through promoting ESCs and HFSCs proliferation and elevating the expression of genes associated with stem cells and cell adhesion. This may provide a valuable alternative strategy to promote wound healing and reepithelialization by modulating the proliferation of skin derived stem cells and regulating genes related to cell adhesion.

Oxygen releasing patches based on carbohydrate polymer and protein hydrogels for diabetic wound healing: A review

Diabetic wounds are among the major healthcare challenges, consuming billions of dollars of resources and resulting in high numbers of morbidity and mortality every year. Lack of sufficient oxygen supply is one of the most dominant causes of impaired healing in diabetic wounds. Numerous clinical and experimental studies have demonstrated positive outcomes as a result of delivering oxygen at the diabetic wound site, including enhanced angiogenesis, antibacterial and cell proliferation activities. However, prolonged and sustained delivery of oxygen to improve the wound healing process has remained a major challenge due to rapid release of oxygen from oxygen sources and limited penetration of oxygen into deep skin tissues. Hydrogels made from sugar-based polymers such as chitosan and hyaluronic acid, and proteins such as gelatin, collagen and hemoglobin have been widely used to deliver oxygen in a sustained delivery mode. This review presents an overview of the recent advances in oxygen releasing hydrogel based patches as a therapeutic modality to enhance diabetic wound healing. Various types of oxygen releasing wound healing patch have been discussed along with their fabrication method, release profile, cytocompatibility and in vivo results. We also briefly discuss the challenges and prospects related to the application of oxygen releasing biomaterials as wound healing therapeutics.

Development and Prospective Applications of 3D Membranes as a Sensor for Monitoring and Inducing Tissue Regeneration

For decades, tissue regeneration has been a challenging issue in scientific modeling and human practices. Although many conventional therapies are already used to treat burns, muscle injuries, bone defects, and hair follicle injuries, there remains an urgent need for better healing effects in skin, bone, and other unique tissues. Recent advances in three-dimensional (3D) printing and real-time monitoring technologies have enabled the creation of tissue-like membranes and the provision of an appropriate microenvironment. Using tissue engineering methods incorporating 3D printing technologies and biomaterials for the extracellular matrix (ECM) containing scaffolds can be used to construct a precisely distributed artificial membrane. Moreover, advances in smart sensors have facilitated the development of tissue regeneration. Various smart sensors may monitor the recovery of the wound process in different aspects, and some may spontaneously give feedback to the wound sites by releasing biological factors. The combination of the detection of smart sensors and individualized membrane design in the healing process shows enormous potential for wound dressings. Here, we provide an overview of the advantages of 3D printing and conventional therapies in tissue engineering. We also shed light on different types of 3D printing technology, biomaterials, and sensors to describe effective methods for use in skin and other tissue regeneration, highlighting their strengths and limitations. Finally, we highlight the value of 3D bioengineered membranes in various fields, including the modeling of disease, organ-on-a-chip, and drug development.

Hydrogen Attenuates Inflammation by Inducing Early M2 Macrophage Polarization in Skin Wound Healing

The heterogeneous and highly plastic cell populations of macrophages are important mediators of cellular responses during all stages of wound healing, especially in the inflammatory stage. Molecular hydrogen (H₂), which has potent antioxidant and anti-inflammatory effects, has been shown to promote M2 polarization in injury and disease. However, more in vivo time series studies of the role of M1-to-M2 polarization in wound healing are needed. In the current study, we performed time series experiments on a dorsal full-thickness skin defect mouse model in the inflammatory stage to examine the effects of H₂ inhalation. Our results revealed that H₂ could promote very early M1-to-M2 polarization (on days 2-3 post wounding, 2-3 days earlier than in conventional wound healing), without disturbing the functions of the M1 phenotype. Time series analysis of the transcriptome, blood cell counts, and multiple cytokines further indicated that peripheral blood monocytes were a source of H₂-induced M2 macrophages and that the functions of H₂ in macrophage polarization were not only dependent on its antioxidant effects. Therefore, we believe that H₂ could reduce inflammation in wound care by shifting early macrophage polarization in clinical settings.