The interplay between extracellular matrix and progenitor/stem cells during wound healing: Opportunities and future directions

Current progress of protein-based dressing for wound healing applications - A review

Protein-based wound dressings have garnered increasing interest in recent years owing to their distinct physical, chemical, and biological characteristics. The intricate molecular composition of proteins gives rise to unique characteristics, such as exceptional biocompatibility, biodegradability, and responsiveness, which contribute to the promotion of wound healing. Wound healing is an intricate and ongoing process influenced by multiple causes, and it consists of four distinct phases. Various treatments have been developed to repair different types of skin wounds, thanks to advancements in medical technology and the recognition of the diverse nature of wounds. This review has literature reviewed within the last 3-5 years-the recent progress and development of protein in wound dressings and the fundamental properties of an ideal wound dressing. Herein, the recent strides in protein-based state-of-the-art wound dressing emphasize the significant challenges and summarize future perspectives for wound healing applications.

Efficacy and Safety of Corticosteroid in Combination with 5-Fluorouracil in the Treatment of Keloids and Hypertrophic Scars: A Systematic Review and Meta-analysis

BACKGROUND

Addressing hypertrophic scars and keloids poses a significant challenge in the realm of preventive and curative medicine. Combination corticosteroid with 5-fluorouracil (5-FU) is presumed to enhance the treatment of hypertrophic scars and keloids, although supportive evidence is lacking. This study is aimed at comparing the efficacy and safety profile of a combined corticosteroid and 5-FU regimen in treating hypertrophic scars and keloids.

METHODS

A comprehensive search was conducted for pertinent studies across various databases, including Web of Science, PubMed, Google Scholar, Cochrane Library, and Medline. The calculation of weighted mean difference (WMD), risk ratios (RR), odds ratios (OR), and 95% confidence intervals (CIs) was executed. Additionally, the Cochrane Collaboration's Risk of Bias Tool was utilized to evaluate potential bias risks.

RESULTS

A total of 15 studies were involved. The effectiveness based on patient self-assessment and the effectiveness based on observer assessment were significantly higher in the corticosteroid+5-FU group compared to those treated with control. A meta-analysis of scar height showed that the corticosteroid+5-FU group performed better than the control group (WMD = -0.38, 95% CI -0.58 to -0.18). There was no significant difference between the corticosteroid+5-FU group and the control group in improving scar vascularity, pliability and pigmentation. The result revealed that the corticosteroid+5-FU group of patients had less adverse effect of hypopigmentation, skin atrophy and telangiectasia than the control group.

CONCLUSION

The combined use of corticosteroids and 5-FU appears to be a more effective strategy for the treatment and prevention of hypertrophic scars and keloids, as evidenced by greater improvements in scar height and overall effectiveness, coupled with a reduced incidence of side effects.

LEVEL OF EVIDENCE II

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Unlocking the potential of flavonoid-infused drug delivery systems for diabetic wound healing with a mechanistic exploration

Diabetes is one of the common endocrine disorders generally characterized by elevated levels of blood sugar. It can originate either from the inability of the pancreas to synthesize insulin, which is considered as an autoimmune disorder, or the reduced production of insulin, considered as insulin resistivity. A wound can be defined as a condition of damage to living tissues including skin, mucous membrane and other organs as well. Wounds get complicated with respect to time based on specific processes like diabetes mellitus, obesity and immunocompromised conditions. Proper growth and functionality of the epidermis gets sustained due to impaired diabetic wound healing which shows a sign of dysregulated wound healing process. In comparison with synthetic medications, phytochemicals like flavonoids, tannins, alkaloids and glycosides have gained enormous importance relying on their distinct potential to heal diabetic wounds. Flavonoids are one of the most promising and important groups of natural compounds which can be used to treat acute as well as chronic wounds. Flavonoids show excellent properties due to the presence of hydroxyl groups in their chemical structure, which makes this class of compounds different from others. Based on the novel principles of nanotechnology via utilizing suitable drug delivery systems, the delivery of bioactive constituents from plant source amplifies the wound-healing mechanism, minimizes complexities and enhances bioavailability. Hence, the encapsulation and applicability of flavonoids with an emphasis on mechanistic route and wound-healing therapeutics have been highlighted in the subsequent study with focus on multiple drug delivery systems.

Mesenchymal stem cell therapy using Pal-KTTKS-enriched carboxylated cellulose improves burn wound in rat model

Despite the great progress in developing wound dressings, delayed wound closure still remains a global challenge. Thus, developing novel wound dressings and employing advanced strategies, including tissue engineering, are urgently desired. The carboxylated cellulose was developed through the in situ synthesis method and further reinforced by incorporating pal-KTTKS to stimulate collagen synthesis and improve wound healing. The developed composites supported cell adhesion and proliferation and showed good biocompatibility. To boost wound-healing performance, adipose-derived mesenchymal stem cells (MSC) were seeded on the pal-KTTKS-enriched composites to be implanted in a rat model of burn wound healing. Healthy male rats were randomly divided into four groups and wound-healing performance of Vaseline gauze (control), carboxylated cellulose (CBC), pal-KTTKS-enriched CBC (KTTKS-CBC), and MSCs seeded on the KTTKS-CBC composites (MSC-KTTKS-CBC) were evaluated on days 3, 7, and 14 post-implantation. In each group, the designed therapeutic dressings were renewed every 5 days to increase wound-healing performance. We found that KTTKS-CBC and MSC-KTTKS-CBC composites exhibited significantly better wound healing capability, as evidenced by significantly alleviated inflammation, increased collagen deposition, improved angiogenesis, and considerably accelerated wound closure. Nevertheless, the best wound-healing performance was observed in the MSC-KTTKS-CBC groups among all four groups. This research suggests that the MSC-KTTKS-CBC composite offers a great deal of promise as a wound dressing to enhance wound regeneration and expedite wound closure in the clinic.

Hyaluronic Acid-Dopamine-NCSN Hydrogel Combined With Extracellular Matrix Promotes Wound Healing

The skin barrier is essential to prevent pathogenic invasion. When injury occurs, multiple biological pathways are promptly activated and wound repair processes are triggered. The effective healing of wounds is essential for survival, and dysfunction could result from aberrant wound repair. Preparation of many hydrogels, which involve the addition of growth/cell factors or mimic extracellular matrix (ECM) components, has not resulted in significant advances in tissue recovery. ECM contains a large number of biologically active molecules that activate a variety of cellular transduction pathways, which are essential for wound repair. Here, this work prepares hyaluronic acid-dopamine-thiourea (HA-DA-NCSN) hydrogels exhibiting ultrafast gelation in situ, following the methods of Xu et al., and subsequently designs a hydrogel containing ECM particles. In addition, the loaded ECM material, specifically decellularized ECM material, not only enhances the strength of the hydrogel network, but also delivers bioactive substances that make it a suitable platform for skin wound repair. The ECM hydrogel has great potential as an efficient bioactive wound dressing. This research suggests that this strategy is likely to improve skin wound closure in rat skin wound models.

The role of oxygen tension in cell fate and regenerative medicine: implications of hypoxia/hyperoxia and free radicals

Oxygen pressure plays an integral role in regulating various aspects of cellular biology. Cell metabolism, proliferation, morphology, senescence, metastasis, and angiogenesis are some instances that are affected by different tensions of oxygen. Hyperoxia or high oxygen concentration, enforces the production of reactive oxygen species (ROS) that disturbs physiological homeostasis, and consequently, in the absence of antioxidants, cells and tissues are directed to an undesired fate. On the other side, hypoxia or low oxygen concentration, impacts cell metabolism and fate strongly through inducing changes in the expression level of specific genes. Thus, understanding the precise mechanism and the extent of the implication of oxygen tension and ROS in biological events is crucial to maintaining the desired cell and tissue function for application in regenerative medicine strategies. Herein, a comprehensive literature review has been performed to find out the impacts of oxygen tensions on the various behaviors of cells or tissues.

Integration of polysaccharide electrospun nanofibers with microneedle arrays promotes wound regeneration: A review

Utilizing electrospun nanofibers and microneedle arrays in wound regeneration has been practiced for several years. Researchers have recently asserted that using multiple methods concurrently might enhance efficiency, despite the inherent strengths and weaknesses of each individual approach. The combination of microneedle arrays with electrospun nanofibers has the potential to create a drug delivery system and wound healing method that offer improved efficiency and accuracy in targeting. The use of microneedles with nanofibers allows for precise administration of pharmaceuticals due to the microneedles' capacity to pierce the skin and the nanofibers' role as a drug reservoir, resulting in a progressive release of drugs over a certain period of time. Electrospun nanofibers have the ability to imitate the extracellular matrix and provide a framework for cellular growth and tissue rejuvenation, while microneedle arrays show potential for enhancing tissue regeneration and enhancing the efficacy of wound healing. The integration of electrospun nanofibers with microneedle arrays may be customized to effectively tackle particular obstacles in the fields of wound healing and drug delivery. However, some issues must be addressed before this paradigm may be fully integrated into clinical settings, including but not limited to ensuring the safety and sterilization of these products for transdermal use, optimizing manufacturing methods and characterization of developed products, larger-scale production, optimizing storage conditions, and evaluating the inclusion of multiple therapeutic and antimicrobial agents to increase the synergistic effects in the wound healing process. This research examines the combination of microneedle arrays with electrospun nanofibers to enhance the delivery of drugs and promote wound healing. It explores various kinds of microneedle arrays, the materials and processes used, and current developments in their integration with electrospun nanofibers.

Cell cycle control by cell-matrix interactions

Cell adhesion to the extracellular matrix (ECM) is required for normal cell cycle progression and accurate cell division. However, how cell adhesion to the wide range of ECM proteins found in human tissues influences the cell cycle is not fully understood. The composition and physical properties of the ECM can have profound effects on cell proliferation but can also promote cell cycle exit and quiescence. Furthermore, during tumor development and progression, changes in the ECM can drive both cancer cell proliferation and dormancy. Cell-matrix adhesion is primarily sensed via integrin-associated adhesion complexes, which in turn are regulated by the cell cycle machinery. In particular, cyclin-dependent kinase 1 (CDK1) has been shown to play a crucial role in regulating adhesion complexes during interphase and entry into mitosis. These reciprocal links between cell cycle progression and cell-matrix interactions are now being identified.

Pathogenesis of Common Ocular Diseases: Emerging Trends in Extracellular Matrix Remodeling

The prevalence of visual impairments in human societies is worrying due to retinopathy complications of several chronic diseases such as diabetes, cardiovascular diseases, and many more that are on the rise worldwide. Since the proper function of this organ plays a pivotal role in people's quality of life, identifying factors affecting the development/exacerbation of ocular diseases is of particular interest among ophthalmology researchers. The extracellular matrix (ECM) is a reticular, three-dimensional (3D) structure that determines the shape and dimensions of tissues in the body. The ECM remodeling/hemostasis is a critical process in both physiological and pathological conditions. It consists of ECM deposition, degradation, and decrease/increase in the ECM components. However, disregulation of this process and an imbalance between the synthesis and degradation of ECM components are associated with many pathological situations, including ocular disorders. Despite the impact of ECM alterations on the development of ocular diseases, there is not much research conducted in this regard. Therefore, a better understanding in this regard, can pave the way toward discovering plausible strategies to either prevent or treat eye disorders. In this review, we will discuss the importance of ECM changes as a sentimental factor in various ocular diseases based on the research done up to now.

Age-Related Alterations in Mesenchymal Stem Cell Function: Understanding Mechanisms and Seeking Opportunities to Bypass the Cellular Aging

Undoubtedly, mesenchymal stem cells (MSCs) are the most common cell therapy candidates in clinical research and therapy. They not only exert considerable therapeutic effects to alleviate inflammation and promote regeneration, but also show low-immunogenicity properties, which ensure their safety following allogeneic transplantation. Thanks to the necessity of providing a sufficient number of MSCs to achieve clinically efficient outcomes, prolonged in vitro cultivation is indisputable. However, either following long-term in vitro expansion or aging in elderly individuals, MSCs face cellular senescence. Senescent MSCs undergo an impairment in their function and therapeutic capacities and secrete degenerative factors which negatively affect young MSCs. To this end, designing novel investigations to further elucidate cellular senescence and to pave the way toward finding new strategies to reverse senescence is highly demanded. In this review, we will concisely discuss current progress on the detailed mechanisms of MSC senescence and various inflicted changes following aging in MSC. We will also shed light on the examined strategies underlying monitoring and reversing senescence in MSCs to bypass the comprised therapeutic efficacy of the senescent MSCs.

Enhancing angiogenesis: Innovative drug delivery systems to facilitate diabetic wound healing

Diabetic wounds (DW) constitute a substantial burden on global healthcare owing to their widespread occurrence as a complication of diabetes. Angiogenesis, a crucial process, plays a pivotal role in tissue recovery by supplying essential oxygen and nutrients to the injury site. Unfortunately, in diabetes mellitus, various factors disrupt angiogenesis, hindering wound healing. While biomaterials designed to enhance angiogenesis hold promise for the treatment of DWs, there is an urgent need for more in-depth investigations to fully unlock their potential in clinical management. In this review, we explore the intricate mechanisms of angiogenesis that are crucial for DW recovery. We introduce a rational design for angiogenesis-enhancing drug delivery systems (DDS) and provide a comprehensive summary and discussion of diverse biomaterials that enhance angiogenesis for facilitating DW healing. Lastly, we address emerging challenges and prospects in angiogenesis-enhancing DDS for facilitating DW healing, aiming to offer a comprehensive understanding of this critical healthcare issue and potential solutions.

Antimicrobial Biomaterials for Chronic Wound Care

Chronic wounds encompass a myriad of lesions, including venous and arterial leg ulcers, diabetic foot ulcers (DFUs), pressure ulcers, non-healing surgical wounds and others. Despite the etiological differences, chronic wounds share several features at a molecular level. The wound bed is a convenient environment for microbial adherence, colonization and infection, with the initiation of a complex host-microbiome interplay. Chronic wound infections with mono- or poly-microbial biofilms are frequent and their management is challenging due to tolerance and resistance to antimicrobial therapy (systemic antibiotic or antifungal therapy or antiseptic topicals) and to the host's immune defense mechanisms. The ideal dressing should maintain moisture, allow water and gas permeability, absorb wound exudates, protect against bacteria and other infectious agents, be biocompatible, be non-allergenic, be non-toxic and biodegradable, be easy to use and remove and, last but not least, it should be cost-efficient. Although many wound dressings possess intrinsic antimicrobial properties acting as a barrier to pathogen invasion, adding anti-infectious targeted agents to the wound dressing may increase their efficiency. Antimicrobial biomaterials may represent a potential substitute for systemic treatment of chronic wound infections. In this review, we aim to describe the available types of antimicrobial biomaterials for chronic wound care and discuss the host response and the spectrum of pathophysiologic changes resulting from the contact between biomaterials and host tissues.

3D bioprinting of a gradient stiffened gelatin-alginate hydrogel with adipose-derived stem cells for full-thickness skin regeneration

Current hydrogel-based scaffolds offer a promising approach to accelerate tissue regeneration, but great challenges remain in developing platforms that mimic the physical microenvironment of tissues combined with therapeutic biological cues. Here, a 3D bioprinting gelatin-alginate hydrogel for the construction of gradient composite scaffolds that mimic the dermal stiffness microenvironment was developed for architecture construction by extruding the bioink on calcium-containing substrates to achieve gradient secondary cross-linking, meanwhile, adipose-derived stem cells were encapsulated in the present hydrogels for therapeutic purposes. The gradient-stiffness scaffold exhibited good stability and biocompatibility as well as enhanced proliferation and migration of the adipose-derived stem cells. In addition, the promoted angiogenesis and healing efficiency was demonstrated via the animal wound model and was mainly attributed to the enhanced paracrine secretion of adipose-derived stem cells by the physical microenvironment provided within the gradient stiffness scaffold. The current 3D printed gradient scaffolds provide adipose-derived stem cells with a distinct yet successive architecture rather than the typical uniform microenvironment to accelerate skin regeneration, which may have broader applications in other chronic wounds or tissue defects.

Cellular rejuvenation: molecular mechanisms and potential therapeutic interventions for diseases

The ageing process is a systemic decline from cellular dysfunction to organ degeneration, with more predisposition to deteriorated disorders. Rejuvenation refers to giving aged cells or organisms more youthful characteristics through various techniques, such as cellular reprogramming and epigenetic regulation. The great leaps in cellular rejuvenation prove that ageing is not a one-way street, and many rejuvenative interventions have emerged to delay and even reverse the ageing process. Defining the mechanism by which roadblocks and signaling inputs influence complex ageing programs is essential for understanding and developing rejuvenative strategies. Here, we discuss the intrinsic and extrinsic factors that counteract cell rejuvenation, and the targeted cells and core mechanisms involved in this process. Then, we critically summarize the latest advances in state-of-art strategies of cellular rejuvenation. Various rejuvenation methods also provide insights for treating specific ageing-related diseases, including cellular reprogramming, the removal of senescence cells (SCs) and suppression of senescence-associated secretory phenotype (SASP), metabolic manipulation, stem cells-associated therapy, dietary restriction, immune rejuvenation and heterochronic transplantation, etc. The potential applications of rejuvenation therapy also extend to cancer treatment. Finally, we analyze in detail the therapeutic opportunities and challenges of rejuvenation technology. Deciphering rejuvenation interventions will provide further insights into anti-ageing and ageing-related disease treatment in clinical settings.

Biopolymer-Based Wound Dressings with Biochemical Cues for Cell-Instructive Wound Repair

Regenerative medicine is an active research sphere that focuses on the repair, regeneration, and replacement of damaged tissues and organs. A plethora of innovative wound dressings and skin substitutes have been developed to treat cutaneous wounds and are aimed at reducing the length or need for a hospital stay. The inception of biomaterials with the ability to interact with cells and direct them toward desired lineages has brought about innovative designs in wound healing and tissue engineering. This cellular engagement is achieved by cell cues that can be biochemical or biophysical in nature. In effect, these cues seep into innate repair pathways, cause downstream cell behaviours and, ultimately, lead to advantageous healing. This review will focus on biomolecules with encoded biomimetic, instructive prompts that elicit desired cellular domino effects to achieve advanced wound repair. The wound healing dressings covered in this review are based on functionalized biopolymeric materials. While both biophysical and biochemical cues are vital for advanced wound healing applications, focus will be placed on biochemical cues and in vivo or clinical trial applications. The biochemical cues aforementioned will include peptide therapy, collagen matrices, cell-based therapy, decellularized matrices, platelet-rich plasma, and biometals.

Involvement of Inflammation and Its Resolution in Disease and Therapeutics

Inflammation plays a critical role in the response to and survival from injuries and/or infections. It occurs in two phases: initiation and resolution; however, when these events do not resolve and persist over time, the inflammatory response becomes chronic, prompting diseases that affect several systems and organs, such as the vasculature and the skin. Here, we reviewed inflammation that occurs in selected infectious and sterile pathologies. Thus, the immune processes induced by bacterial sepsis as well as T. cruzi and SARS-CoV-2 infections are shown. In addition, vaccine adjuvants as well as atherosclerosis are revised as examples of sterile-mediated inflammation. An example of the consequences of a lack of inflammation resolution is given through the revision of wound healing and chronic wounds. Then, we revised the resolution of the latter through advanced therapies represented by cell therapy and tissue engineering approaches, showing how they contribute to control chronic inflammation and therefore wound healing. Finally, new pharmacological insights into the management of chronic inflammation addressing the resolution of inflammation based on pro-resolving mediators, such as lipoxin, maresin, and resolvins, examining their biosynthesis, biological properties, and pharmacokinetic and pharmaceuticals limitations, are given. We conclude that resolution pharmacology and advanced therapies are promising tools to restore the inflammation homeostasis.

Investigation of the Properties of Linen Fibers and Dressings

In antiquity, flax was used as a dressing for healing wounds. Currently, work is underway on the genetic modification of flax fibers to improve their properties. Genetic modifications have resulted in an increased content of antioxidants and more favorable mechanical properties. The works published so far have presented independent tests of fibers and dressings after appropriate technological treatments in cell cultures. This study aimed to compare the properties of the fibers and the dressing produced in cell cultures—hamster fibroblasts—V79. The research material was traditional NIKE fibers; genetically modified M, B, and MB fibers; and linen dressings obtained from these fibers. The extract from 48-h incubation of 40 mg of fiber in the culture medium, which was desolved into 10, 20, and 30 mg, was administered to the cell culture. On the other hand, a linen dressing was placed on cells with an area of 0.5 cm², 1 cm², 1.5 cm², and 2 cm². Cells with fiber or dressing were incubated for 48 h, and then, biological tests were performed, including cell viability (in propidium iodide staining), cell proliferation (in the SRB assay), evaluation of the intracellular free radical level (in the DCF-DA assay), genotoxicity (in the comet assay), assessment of the apoptotic and necrotic cells (in staining anexin-V and iodide propidium), the course of the cell cycle, and the scratch test. The correlation between apoptosis and genotoxicity and the levels of free radicals and genotoxicity were determined for the tested linen fibers and fabrics. The tests presented that the fibers are characterized by the ability to eliminate damaged cells in the elimination phase. However, the obtained fabrics gain different properties during the technological processing of the fibers into linen dressings. Linen fabrics have better regenerative properties for cells than fibers. The linseed dressing made of MB fiber has the most favorable regenerative properties.

Innovative Treatment Strategies to Accelerate Wound Healing: Trajectory and Recent Advancements

Wound healing is highly specialized dynamic multiple phase process for the repair of damaged/injured tissues through an intricate mechanism. Any failure in the normal wound healing process results in abnormal scar formation, and chronic state which is more susceptible to infections. Chronic wounds affect patients’ quality of life along with increased morbidity and mortality and are huge financial burden to healthcare systems worldwide, and thus requires specialized biomedical intensive treatment for its management. The clinical assessment and management of chronic wounds remains challenging despite the development of various therapeutic regimens owing to its painstakingly long-term treatment requirement and complex wound healing mechanism. Various conventional approaches such as cell therapy, gene therapy, growth factor delivery, wound dressings, and skin grafts etc., are being utilized for promoting wound healing in different types of wounds. However, all these abovementioned therapies are not satisfactory for all wound types, therefore, there is an urgent demand for the development of competitive therapies. Therefore, there is a pertinent requirement to develop newer and innovative treatment modalities for multipart therapeutic regimens for chronic wounds. Recent developments in advanced wound care technology includes nanotherapeutics, stem cells therapy, bioengineered skin grafts, and 3D bioprinting-based strategies for improving therapeutic outcomes with a focus on skin regeneration with minimal side effects. The main objective of this review is to provide an updated overview of progress in therapeutic options in chronic wounds healing and management over the years using next generation innovative approaches. Herein, we have discussed the skin function and anatomy, wounds and wound healing processes, followed by conventional treatment modalities for wound healing and skin regeneration. Furthermore, various emerging and innovative strategies for promoting quality wound healing such as nanotherapeutics, stem cells therapy, 3D bioprinted skin, extracellular matrix-based approaches, platelet-rich plasma-based approaches, and cold plasma treatment therapy have been discussed with their benefits and shortcomings. Finally, challenges of these innovative strategies are reviewed with a note on future prospects.

A Beginner's Introduction to Skin Stem Cells and Wound Healing

The primary function of the skin is that of a physical barrier against the environment and diverse pathogens; therefore, its integrity is essential for survival. Skin regeneration depends on multiple stem cell compartments within the epidermis, which, despite their different transcriptional and proliferative capacity, as well as different anatomical location, fall under the general term of skin stem cells (SSCs). Skin wounds can normally heal without problem; however, some diseases or extensive damage may delay or prevent healing. Non-healing wounds represent a serious and life-threatening scenario that may require advanced therapeutic strategies. In this regard, increased focus has been directed at SSCs and their role in wound healing, although emerging therapeutical approaches are considering the use of other stem cells instead, such as mesenchymal stem cells (MSCs). Given its extensive and broad nature, this review supplies newcomers with an introduction to SSCs, wound healing, and therapeutic strategies for skin regeneration, thus familiarizing the reader with the subject in preparation for future in depth reading.