Metalloproteinases and Wound Healing

The Effect of Low-Frequency Magnetic Fields with Low Induction and Red LED Light on Keratinocyte Biological Activity-An In Vitro Research Model

For several decades, there has been growing interest in the influence of low-frequency magnetic fields (LFMFs) and red LED light on the healing process. Keratinocytes are cells that play a significant role in the process of wound healing and tissue regeneration. A human keratinocyte cell line (HaCaT) was exposed to an LFMF with low induction (180-195 Hz; 60 µT, magnetostimulation), red LED light (630 nm; 300 mW, LED therapy), and their combined action (magneto-LED therapy) in in vitro culture conditions. On day 4 and 8 of the experiment, the following parameters were determined: adhesion/proliferation, adenylate kinase (AK), nitric oxide (NO), cytokines (IL-1β, IL-6, IL-8, IL-10, IL-12p70, TNF-α), metalloproteinases (MMP-2, MMP-9), and collagen IV. It was shown that magnetostimulation caused an increase in keratinocyte adhesion/proliferation and IL-8 secretion and a decrease in IL-12 secretion. The LED therapy resulted in a transient increase in the secretion of NO and cytokines IL-1, IL-12, and IL-6 in keratinocytes. The use of magneto-LED therapy resulted in an increase in keratinocyte adhesion/proliferation, the secretion of cytokines IL-6 and IL-8, and NO with a simultaneous decrease in MMP-9 secretion. The results of our studies showed that the action of an LFMF with low-induction and LED light on keratinocytes can modulate the biological activity of keratinocytes towards improving the skin healing process.

Antioxidant Effect of a Plant-Derived Extracellular Vesicles' Mix on Human Skin Fibroblasts: Induction of a Reparative Process

Plant-Derived Extracellular Vesicles extracellular vesicles (PDEVs) from organic agriculture (without the use of pesticides and microbicides) contain high levels of antioxidants. Organic PDEVs have shown an increased antioxidant power compared to PDEVs from single plants, suggesting a synergistic effect of the bioactives constitutively expressed in the PDEVs from single fruits. With this study, we wanted to investigate the beneficial effects of a mix of PDEVs on human skin cells. We found detectable levels of citric acid, ascorbic acid, glutathione, catalase, and SOD in a mix of PDEVs deriving from five different fruits (grape, red orange, papaya, pomegranate, and tangerine). We then treated H2O2-conditioned fibroblasts with the mix of PDEVs. The results showed that the PDEVs' mixture reverted the H2O2-induced redox imbalance, restoring mitochondrial homeostasis, with a strong reduction of mitochondrial anion superoxide and an increase in sirtuin levels. The antioxidant action was consistent with wound repair on a lesion produced in a fibroblast's monolayer. This result was consistent with an increased level of vimentin and matrix metalloproteinase-9, whose expression is directly related to the efficiency of the reparative processes. These data support a beneficial role of PDEVs in both preventing and treating skin injuries through their potent antioxidant and reparative activities.

Hepatocyte growth factor upregulates MMP1 and MMP10 expression and resolves corneal fibrosis

Different therapeutic modalities, including steroids, have been used to treat corneal scarring. However, the ability of steroids to reduce corneal scarring is limited and associated with numerous side effects. Our previous studies have demonstrated that topical hepatocyte growth factor (HGF) after corneal injury suppresses the development of stromal scars. Here, we investigated whether HGF can re-establish corneal clarity and normalize tissue structure in corneas with pre-existing scars. Corneal scarring was induced by mechanically removing the corneal epithelium and the anterior third of the stroma using a hand-held Algerbrush II in C57BL/6 mice. Substantial scar tissue formed by day 10 post-injury, at which time the epithelium was debrided and treated with 0.1% recombinant mouse HGF, 0.1% dexamethasone (steroid) or 0.1% control protein thrice a day for 10 days. Corneal clarity was significantly restored in the HGF treatment group, compared to both the steroid and control protein treatment groups. Moreover, HGF treatment downregulated the expression of αSMA and upregulated the expression of extracellular matrix-remodeling matrix metalloproteinases 1 and 10 (MMP1 and MMP10), suggesting HGF upregulates tissue remodeling molecule MMP1 and 10 to promote tissue restoration. These findings offer novel insights into the mechanisms by which HGF re-establishes corneal clarity, and promotes epithelial regeneration in corneas with pre-existing stromal scarring.

The heterogeneous wound microbiome varies with wound care pain, dressing type, and inflammatory gene expression

Wound dressing changes are essential procedures for wound management. However, ~50% of patients experience severe pain during these procedures despite the availability of analgesic medications, indicating a need for novel therapeutics that address underlying causes of pain. Along with other clinical factors, wound pathogens and inflammatory immune responses have previously been implicated in wound pain. To test whether these factors could contribute to severe pain during wound dressing changes, we conducted an exploratory, cross-sectional analysis of patient-reported pain, inflammatory immune responses, and wound microbiome composition in 445 wounds at the time of a study dressing change. We profiled the bacterial composition of 406 wounds using 16S ribosomal RNA amplicon sequencing and quantified gene expression of 13 inflammatory markers in wound fluid using quantitative real-time polymerase chain reaction (qPCR). Neither inflammatory gene expression nor clinically observed inflammation were associated with severe pain, but Corynebacterium and Streptococcus were of lower relative abundance in wounds of patients reporting severe pain than those reporting little or no pain. Wound microbiome composition differed by wound location, and correlated with six of the inflammatory markers, including complement receptor C5AR1, pro-inflammatory cytokine interleukin (IL)1β, chemokine IL-8, matrix metalloproteinase MMP2, and the antimicrobial peptide encoding cathelicidin antimicrobial peptide. Interestingly, we found a relationship between the wound microbiome and vacuum-assisted wound closure (VAC). These findings identify preliminary, associative relationships between wound microbiota and host factors which motivate future investigation into the directional relationships between wound care pain, wound closure technologies, and the wound microbiome.

Comparative Effectiveness of Diode Laser Therapy and Topical Turmeric Extract Ointment in Promoting Healing of Wounds in a Murine Model

The intricate biological process of wound healing is influenced by a wide range of therapeutic techniques. In this work, the effects of topical turmeric extract ointment and diode laser therapy on wound healing in a mouse model were investigated. Out of the sixty mice, three groups of twenty male mice each were created. Three groups received treatment: the first was a control group that got no treatment; the second group received topical application of 5% curcumin twice a day; and the third group received diode laser therapy, which involved direct laser beam therapy for five minutes a day at an output power of 100 mW at an 810 nm wavelength. Over the course of two weeks, the study examined histological changes and wound closure rates. On days 0 through 14, the wound area was measured with digital calipers to provide quantifiable statistics about the process of healing. In histological analyses, epithelializations, and collagen deposition, in addition to inflammatory cells, were investigated using hematoxylin and eosin staining. It was demonstrated by comparing the outcomes to those of a control group that diode laser therapy and turmeric extract ointment are both successful therapeutic options. The results demonstrate that different therapies, while with differing degrees of effectiveness, greatly quicken the healing process of wounds. According to these results, topical turmeric extract ointment could be used as an additional or supporting therapy to aid in the healing of wounds during medical treatments.

Comparative analysis of human and mouse transcriptomes during skin wound healing

Skin wound healing is a complex process which involves multiple molecular events and the underlying mechanism is not fully understood. We presented a comparative transcriptomic analysis of skin wound healing in humans and mice to identify shared molecular mechanisms across species. We analyzed transcriptomes from three distinct stages of the healing process and constructed protein-protein interaction networks to elucidate commonalities in the healing process. A substantial number of differentially expressed genes (DEGs) were identified in human transcriptomes, particularly upregulated genes before and after wound injury, and enriched in processes related to extracellular matrix organization and leukocyte migration. Similarly, the mouse transcriptome revealed thousands of DEGs, with shared biological processes and enriched KEGG pathways, highlighting a conserved molecular signature in skin wound healing. A total of 21 common DEGs were found across human comparisons, and 591 in mouse comparisons, with four genes (KRT2, MARCKSL1, MMP1, and TNC) consistently differentially expressed in both species, suggesting critical roles in mammalian skin wound healing. The expression trends of these genes were consistent, indicating their potential as therapeutic targets. The molecular network analysis identified five subnetworks associated with collagen synthesis, immunity, cell-cell adhesion, and extracellular matrix, with hub genes such as COL4A1, TLR7, TJP3, MMP13, and HIF1A exhibited significant expression changes before and after wound injury in humans and mice. In conclusion, our study provided a detailed molecular network for understanding the healing process in humans and mice, revealing conserved mechanisms that could help the development of targeted therapies across species.

An Update on Molecular Mechanisms of Scarring-A Narrative Review

Fibroblasts, the principal cellular mediators of connective tissue remodeling, play a crucial role in the formation of physiological and pathological scars. Understanding the intricate interplay between fibroblasts and other cellular and molecular components is essential for elucidating the underlying mechanisms driving scar formation. Hypertrophic scars, keloids and atrophic scars arise from dysregulated wound healing processes characterized by persistent inflammation, aberrant collagen deposition, and impaired extracellular matrix remodeling. Fibroblasts play a central role in the pathogenesis of such pathological scars, driving aberrant extracellular matrix remodeling, subsequently contributing to the formation of raised or depressed fibrotic lesions. The investigation of complex interactions between fibroblasts and the microenvironment is crucial for developing targeted therapeutic interventions aimed at modulating fibroblast activity and improving clinical outcomes in patients with pathological scars. Further research into the molecular pathways governing fibroblast behavior and their heterogeneity holds promise for advancing scar management strategies. This narrative review was performed to shed light on the mechanisms behind scar formation, with a special focus on the role of fibroblasts in the formation of different types of scars, providing insights into the pathophysiology of these conditions. Through the analysis of current knowledge, this review seeks to identify the key cellular and molecular mechanisms involved in fibroblast activation, collagen synthesis, and extracellular matrix remodeling in hypertrophic scar, keloid, or atrophic scar formation.

Eudermic Properties and Chemical-Physical Characterization of Honeys of Different Botanical Origin

Background: Honey is a natural product that, thanks to its composition, particularly the high sugar content, is highly appreciated as an energy nourishment. In addition to sugars, it contains many other substances (carbohydrates, free amino acids, enzymatic proteins, organic acids, polyphenols) from which the therapeutic properties of honey arise: hydrating and osmotic activity, antimicrobial action, and antioxidant and anti-inflammatory power. Objectives: The present work aims to deepen our knowledge/understanding of the activity of skin protection exerted by honey, as a synergic result of its multiple therapeutic effects. Moreover, this study wants to find possible correlations between biological properties and the chemical-physical traits of honey. Methods: To carry out this research, five varieties of citrus honey, one of acacia honey, one of chestnut honey, and one of multifloral honey were used. The honeys were first characterized by chemical-physical analysis and then were subjected to qualitative melissopalynological analysis. Tests were also carried out to evaluate both their antioxidant power and the effect on collagenase, an enzyme involved in the degradation of collagen present in the extracellular matrix and, therefore, in the processes of skin aging. Finally, honey samples were then used in in vitro experiments to assess their action in stimulating cell viability and proliferation on human keratinocytes. Results: Chemical-physical analysis demonstrated a good water content (about 17%), an important sugar content (with the monosaccharides glucose and fructose being the most represented in all the honey samples), various amino acids (with proline remarkably being the highest in all honeys), and a high concentration of polyphenols and total flavonoids (the maximum in chestnut honey, 762 mg/kg and 514 mg/kg, respectively). Conclusions The results obtained in this work confirm the ethnopharmacological use of honey in wound care, bring new scientific knowledge on the use of honey in dermatology, and highlight two fields of excellence, particularly incitrus and chestnut honey.

Targeting Matrix Metalloproteinase-9 for Therapeutic Intervention in Diabetic Foot Ulcers

Diabetic foot ulcers (DFUs) are a complication of diabetes that have long been neglected. To date, a single drug (becaplermin containing platelet-derived growth factor, PDGF) has been approved by the FDA 27 years ago; however, it is seldom used because of its modest efficacy. The standard-of-care for DFUs is debridement, off-loading, and infection control with antibiotics, with hyperbaric oxygen (HBO) therapy being the treatment of last recourse. The paucity of understanding what accelerates diabetic wound healing results in more than 150,000 lower-limb amputations in the United States every year. A new paradigm for treatment of DFUs is proposed based on the higher levels of active matrix metalloproteinase (MMP)-9 with the more severe and infected human DFUs, and the demonstrated detrimental role of MMP-9 and the beneficial repair role of MMP-8 in diabetic mice. Selective inhibition of MMP-9 with the small molecule (R)-ND-336 lowered inflammation, reduced reactive oxygen species (ROS), and increased angiogenesis, without affecting MMP-8 to allow the natural repair mechanisms to take place. (R)-ND-336 showed better efficacy than becaplermin in diabetic mice. Becaplermin (PDGF) and HBO therapy work by decreasing MMP-9, but they do not completely suppress MMP-9 activity.

Wound healing effect of polydeoxyribonucleotide derived from Hibiscus sabdariffa callus via Nrf2 signaling in human keratinocytes

There has been a growing interest in skin recovery in both the medical and cosmetics fields, leading to an increasing number of studies reporting diverse materials being utilized for this purpose. Among them, polydeoxyribonucleotide (PDRN) is known for its efficacy in skin repair processes, while Hibiscus sabdariffa (HS) is recognized for its antioxidant, hypolipidemic, and wound healing properties, including its positive impact on mammalian skin and cells. We hypothesized that these characteristics may have a germane relationship during the healing process. Consequently, we induced calli from HS and then extracted PDRN for use in treating human keratinocytes. PDRN (5 μg/mL) had considerable wound healing effects and wrinkle improvement effects. To confirm its function at the molecular level, we performed real-time polymerase chain reaction, western blotting, and immunocytochemistry. Furthermore, genes related to wound healing (MMP9, Nrf2, KGF, VEGF, SOD2, and AQP3) were significantly upregulated. Additionally, the protein expression of MMP9, AQP3, and CAT, which are closely related to wound healing and antioxidant cascades, was considerably enhanced. Based on cellular morphology and molecular-level evidence, we propose that PDRN from calli of HS can improve wound healing in human keratinocytes. Furthermore, its potential to serve as a novel material in cosmetic products is demonstrated.

Cell line-based in vitro models of normal and chronic bronchitis-like airway mucosa to study the toxic potential of aerosolized palladium nanoparticles

Background

Physiologically relevant cell line-based models of human airway mucosa are needed to assess nanoparticle-mediated pulmonary toxicity for any xenbiotics expsoure study. Palladium nanoparticles (Pd-NP) originating from catalytic converters in vehicles pose health risks. We aimed to develop in vitro airway models to assess the toxic potential of Pd-NP in normal (Non-CB) and chronic bronchitis-like (CB-like) mucosa models.

Methods

Bronchial mucosa models were developed using Epithelial cells (16HBE: apical side) co-cultured with fibroblast (basal side) at an air-liquid interface. Furthermore, both Non-CB and CB-like (IL-13 treatment) models with increased numbers of goblet cells were used. The models were exposed to 3 different doses of aerosolized Pd-NP (0.2, 0.3, and 6 μg/cm2) using XposeALI® and clean air as a control. After 24 h of incubation, the expression of inflammatory (IL6, CXCL8, TNFα, and NFKB), oxidative stress (HMOX1, SOD3, GPx, and GSTA1), and tissue injury/repair (MMP9/TIMP1) markers was assessed using qRT-PCR. The secretion of CXCL-8 and the expression of a tissue injury/repair marker (MMP-9) were measured via ELISA.

Results

Significantly (p < 0.05) increased expressions of CXCL8, IL6, and NFKB were observed at the highest dose of Pd-NP in CB-like models. However, in Non-CB mucosa models, a maximum effect on TNFα and NFKB expression was observed at a medium Pd-NP dose. In Non-CB mucosa models, SOD3 showed a clear dose-dependent response to Pd-NP exposure, while GSTA1 expression was significantly increased (p < 0.05) only at the lowest dose of Pd-NP. The secretion of CXCL-8 increased in a dose-dependent manner in the Non-CB mucosa models following exposure to Pd-NP. In CB-like models, exposure to high concentrations of Pd-NP significantly increased the release of MMP-9 compared to that in other exposure groups.

Conclusion

The combination of our Non-CB and CB-like mucosa models with the XposeALI® system for aerosolized nanoparticle exposure closely mimics in vivo lung environments and cell-particle interactions. Results from these models, utilizing accessible cell lines, will maximize the reliability of in vitro findings in human health risk assessment.

Immortelle Essential-Oil-Enriched Hydrogel for Diabetic Wound Repair: Development, Characterization, and In Vivo Efficacy Assessment

Background: Alarming data revealed that 19% to 34% of adults with diabetes mellitus develop chronic wounds, which are characterized by impaired healing and a higher risk of infections. Inspired by the traditional use of immortelle for wound healing and the lack of scientific evidence regarding how it thoroughly influences tissue regeneration, we aimed to formulate a hydrogel loaded with immortelle essential oil and assess its effectiveness on diabetic excision wounds. Methods: The rheological properties of the hydrogel, an in vivo safety test, as well as wound healing capacity, were determined in rats with induced diabetes and excision wounds. Diabetic rats were divided into four groups: untreated, treated with 1% silver sulfadiazine ointment, treated with a gel base, and treated with the immortelle essential oil-based hydrogel. Results: It was revealed that the hydrogel exerts pseudoplastic behavior and has no potential to act as an irritant, thus highlighting its suitability for skin application. Moreover, analysis of macroscopic, biochemical, and histopathological data revealed that the immortelle essential oil-based hydrogel significantly improves wound repair. Superior re-epithelialization, scar maturation, and increased collagen fiber density were achieved after immortelle essential oil-based gel application. Conclusions: These findings suggest that the immortelle essential oil-based hydrogel could be a natural, safe, and effective wound-healing dressing.

4-aminopyridine attenuates inflammation and apoptosis and increases angiogenesis to promote skin regeneration following a burn injury in mice

Severe thermal skin burns are complicated by inflammation and apoptosis, which delays wound healing and contributes to significant morbidity. Diverse treatments demonstrate limited success in mitigating these processes to accelerate healing. Agents that alter cell behavior to improve healing would alter treatment paradigms. We repurposed 4-aminopyridine (4-AP), a drug approved by the US FDA for multiple sclerosis, to treat severe burns in mice (10-week-old C57BL/6 J male mice weighing 25 ± 3 g). We found that 4-AP, in the early stages of burn healing, significantly reduced the expression of pro-inflammatory cytokines IL1β and TNFα while increasing the expression of anti-inflammatory markers CD206, ARG-1, and IL10. We demonstrated increased intracellular calcium effects of 4-AP through Orai1-pSTAT6 signaling, where 4-AP significantly mitigated inflammatory effects by promoting M2 macrophage differentiation in in-vitro macrophages and post-skin burn tissues. 4-AP attenuated apoptosis, with decreases in apoptotic markers BAX, caspase-9, and caspase-3 and increases in anti-apoptotic markers BCL2 and BCL-XL. Furthermore, 4-AP promoted angiogenesis through increases in the expression of CD31, VEGF, and eNOS. Together, these likely contributed to accelerated burn wound closure, as demonstrated in increased keratinocyte proliferation (K14) and differentiation (K10) markers. In the later stages of burn healing, 4-AP increased TGFβ and FGF levels, which are known to mark the transformation of fibroblasts to myofibroblasts. This was further demonstrated by an increased expression of α-SMA and vimentin, as well as higher levels of collagen I and III, MMP 3, and 9 in mice treated with 4-AP. Our findings support the idea that 4-AP may have a novel, clinically relevant therapeutic use in promoting burn wound healing.

Clinical efficacy and safety of a silver ion-releasing foam dressing on hard-to-heal wounds: a meta-analysis

OBJECTIVE

Delayed or stalled healing in open wounds can result from persisting chronic inflammation related to infection and/or persistent bacterial colonisation and biofilm. Treatment of hard-to-heal wounds focuses on debridement and exudate management, but also on infection prevention and control. Silver dressings have been evaluated in randomised clinical trials (RCTs); this meta-analysis evaluated the efficacy and safety of a silver ion-releasing foam dressing (Biatain Ag; Coloplast A/S, Denmark) to treat hard-to-heal wounds.

METHOD

Literature databases (PubMed and Cochrane Library) were searched for studies on silver ion-releasing foam dressings in the treatment of hard-to-heal wounds. Individual patient data from four RCTs were obtained and included in the meta-analysis.

RESULTS

Findings showed that treatment with the silver ion-releasing foam dressing was associated with a significantly higher relative reduction in wound area after four (least squares-mean difference (LS-MD): -12.55%, 95% confidence interval (CI): (-15.95, -9.16); p<0.01) and six weeks of treatment (LS-MD: -11.94%, 95%CI: (-17.21, -6.68); p<0.01) compared with controls. Significant benefits were also observed for time to disappearance of odour (hazard ratio: 1.61, 95%CI: (1.31, 1.98); p<0.01), relative reduction of exudate (LS-MD: -5.15, 95%CI: (-7.36, -2.94); p<0.01), proportion of patients with periwound erythema (relative risk (RR): 0.81, 95%CI: (0.69; 0.94); p<0.01), and less pain at dressing removal (LS-MD: -0.35, 95%CI: (-0.63, -0.06); p=0.02). No differences regarding safety outcomes were identified.

CONCLUSION

This meta-analysis has demonstrated beneficial outcomes and a good tolerability profile for silver ion-releasing foam dressings in the treatment of moderate-to-highly exuding wounds with delayed healing compared with control dressings.

Expression of wound healing markers in gingival crevicular fluid following root-coverage procedures: A systematic review of randomized clinical trials

OBJECTIVE

Although several surgical techniques have been developed for treatment of gingival recession (GR), the underlying wound healing process remains relatively unexplored. This systematic review aimed to investigate the expression of wound healing markers in gingival crevicular fluid (GCF) before and after surgical treatment of GR.

DESIGN

Randomized clinical trials (RCTs) reporting changes in the expression of GCF markers following any root coverage surgical procedure were identified from 4 electronic databases and manual searches followed by data extraction and result synthesis. The risk of bias (RoB) was assessed using Cochrane RoB 2.0 tool. Overall certainty of evidence was summarized using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) tool.

RESULTS

Four RCTs comprising 100 patients and investigating 15 biomarkers were included. Post-surgery, GCF levels of cytokines and inflammatory proteins were raised during the first 2-10 days of healing. MMP-8 levels increased during the first week followed by a gradual decline. RoB was found to be high for all studies and the overall certainty of evidence was very low.

CONCLUSION

A limited number of studies with large methodological variations precluded reliable conclusions. Well-designed studies powered for GCF markers' levels that follow a standardized protocol for GCF sampling and processing are needed to draw conclusive evidence.

Stimuli-responsive drug delivery systems for inflammatory skin conditions

Inflammatory skin conditions highly influence the quality of life of the patients suffering from these disorders. Symptoms include red, itchy and painful skin lesions, which are visible to the rest of the world, causing stigmatization and a significantly lower mental health of the patients. Treatment options are often unsatisfactory, as they suffer from either low patient adherence or the risk of severe side effects. Considering this, there is a need for new treatments, and notably of new ways of delivering the drugs. Stimuli-responsive drug delivery systems are able to deliver their drug cargo in response to a given stimulus and are, thus, promising for the treatment of inflammatory skin conditions. For example, the use of external stimuli such as ultraviolet light, near infrared radiation, or alteration of magnetic field enables drug release to be precisely controlled in space and time. On the other hand, internal stimuli induced by the pathological condition, including pH alteration in the skin or upregulation of reactive oxygen species or enzymes, can be utilized to create drug delivery systems that specifically target the diseased skin to achieve a better efficacy and safety. In the latter context, however, it is of key importance to match the trigger mechanism of the drug delivery system to the actual pathological features of the specific skin condition. Hence, the focus of this article is placed not only on reviewing stimuli-responsive drug delivery systems developed to treat specific inflammatory skin conditions, but also on critically evaluating their efficacy in the context of specific skin diseases. STATEMENT OF SIGNIFICANCE: Skin diseases affect one-third of the world's population, significantly lowering the quality of life of the patients, who deal with symptoms such as painful and itchy skin lesions, as well as stigmatization due to the visibility of their symptoms. Current treatments for inflammatory skin conditions are often hampered by low patient adherence or serious drug side effects. Therefore, more emphasis should be placed on developing innovative formulations that provide better efficacy and safety for patients. Stimuli-responsive drug delivery systems hold considerable promise in this regard, as they can deliver their cargo precisely where and when it is needed, reducing adverse effects and potentially offering better treatment outcomes.

Quantification of age-related changes in the structure and mechanical function of skin with multiscale imaging

The mechanical properties of skin change during aging but the relationships between structure and mechanical function remain poorly understood. Previous work has shown that young skin exhibits a substantial decrease in tissue volume, a large macro-scale Poisson's ratio, and an increase in micro-scale collagen fiber alignment during mechanical stretch. In this study, label-free multiphoton microscopy was used to quantify how the microstructure and fiber kinematics of aged mouse skin affect its mechanical function. In an unloaded state, aged skin was found to have less collagen alignment and more non-enzymatic collagen fiber crosslinks. Skin samples were then loaded in uniaxial tension and aged skin exhibited a lower mechanical stiffness compared to young skin. Aged tissue also demonstrated less volume reduction and a lower macro-scale Poisson's ratio at 10% uniaxial strain, but not at 20% strain. The magnitude of 3D fiber realignment in the direction of loading was not different between age groups, and the amount of realignment in young and aged skin was less than expected based on theoretical fiber kinematics affine to the local deformation. These findings provide key insights on how the collagen fiber microstructure changes with age, and how those changes affect the mechanical function of skin, findings which may help guide wound healing or anti-aging treatments.

Direct and cell-mediated EV-ECM interplay

Extracellular vesicles (EV) are a heterogeneous group of lipid particles excreted by cells. They play an important role in regeneration, development, inflammation, and cancer progression, together with the extracellular matrix (ECM), which they constantly interact with. In this review, we discuss direct and indirect interactions of EVs and the ECM and their impact on different physiological processes. The ECM affects the secretion of EVs, and the properties of the ECM and EVs modulate EVs' diffusion and adhesion. On the other hand, EVs can affect the ECM both directly through enzymes and indirectly through the modulation of the ECM synthesis and remodeling by cells. This review emphasizes recently discovered types of EVs bound to the ECM and isolated by enzymatic digestion, including matrix-bound nanovesicles (MBV) and tissue-derived EV (TiEV). In addition to the experimental studies, computer models of the EV-ECM-cell interactions, from all-atom models to quantitative pharmacology models aiming to improve our understanding of the interaction mechanisms, are also considered. STATEMENT OF SIGNIFICANCE: Application of extracellular vesicles in tissue engineering is an actively developing area. Vesicles not only affect cells themselves but also interact with the matrix and change it. The matrix also influences both cells and vesicles. In this review, different possible types of interactions between vesicles, matrix, and cells are discussed. Furthermore, the united EV-ECM system and its regulation through the cellular activity are presented.

Topical amlodipine-loaded solid lipid nanoparticles for enhanced burn wound healing: A repurposed approach

Burn wounds are a complicated process with ongoing psychological and physical issues for the affected individuals. Wound healing consists of multifactorial molecular mechanisms and interactions involving; inflammation, proliferation, angiogenesis, and matrix remodeling. Amlodipine (ADB), widely used in cardiovascular disorders, demonstrated antioxidant and anti-inflammatory effects in some non-cardiovascular studies. It was reported that amlodipine is capable of promoting the healing process by regulation of collagen production, extracellular matrix, re-epithelialization and wound healing through its vasodilation and angiogenic activity. The objective of the current study is to appraise the wound healing capacity of amlodipine-loaded SLN (ADB-SLN) integrated into a hydrogel. The in-vitro characterization revealed that the optimized formulation was nanometric (190.4 ± 1.6 nm) with sufficiently high entrapment efficiency (88 % ± 1.4) and sustained ADB release (85.45 ± 4.45 % after 12 h). Furthermore, in-vivo evaluation was conducted on second-degree burns induced in male Sprague-Dawley rats. ADB-SLN gel revealed a high wound contraction rate and a significant improvement in skin regeneration and inflammatory biomarkers levels, confirming its efficiency in enhancing wound healing compared to other tested and commercial formulations. To conclude, the present findings proved that ADB-SLN integrated hydrogel offers a promising novel therapy for burn wound healing with a maximum therapeutic value.

The role of extracellular matrix in angiogenesis: Beyond adhesion and structure

While the extracellular matrix (ECM) has long been recognized for its structural contributions, anchoring cells for adhesion, providing mechanical support, and maintaining tissue integrity, recent efforts have elucidated its dynamic, reciprocal, and diverse properties on angiogenesis. The ECM modulates angiogenic signaling and mechanical transduction, influences the extent and degree of receptor activation, controls cellular behaviors, and serves as a reservoir for bioactive macromolecules. Collectively, these factors guide the formation, maturation, and stabilization of a functional vascular network. This review aims to shed light on the versatile roles of the ECM in angiogenesis, transcending its traditional functions as a mere structural material. We will explore its engagement and synergy in signaling modulation, interactions with various angiogenic factors, and highlight its importance in both health and disease. By capturing the essence of the ECM's diverse functionalities, we highlight the significance in the broader context of vascular biology, enabling the design of novel biomaterials to engineer vascularized tissues and their potential therapeutic implications.

Evaluation of Full Thickness Wounds Following Application of a Visco-Liquid Hemostat in a Swine Model

Wound healing is a complex dynamic biomechanical process as the body attempts to restore the integrity of traumatized or devitalized tissues. There are four stages of wound of healing that begins with hemostasis followed by inflammation, proliferation and finally weeks later wound remodeling. Full thickness wounds usually are covered with a dressing material after hemostasis, which allows for controlled hydration. We investigated the potential of a visco-liquid hemostat, polyhedral oligomeric silsesquioxane (POSS), for providing hemostasis and to maintain a microenvironment in the wound bed that would maintain moisture content and promote early re-epithelialization. We hypothesized that the hemostatic agent POSS if left in the wound bed would maintain a protective barrier and accelerate wound healing similar to using saline to irrigate the wound to keep the wound moist. We compared the early phase of wound repair (3-7 days) in a porcine full thickness wound model to evaluate the efficacy of the material. Biopsies were taken after 3 and 7 days to determine the acute response of the POSS hemostat or saline on inflammation, cell migration, concentrations of metalloproteinase (MMPs), and tissue inhibitors of metalloproteinase (TIMPs). Accelerated healing was observed in POSS treated wounds by changes in wound contraction, keratinocyte migration, and development of granulation tissue in comparison to saline treated wounds. Increased concentrations at day 3 of MMP-2, MMP-3, and in MMP-1 at day 7 in POSS treated wounds compared to saline coincide with keratinocyte migration observed in the tissue histology and changes in wound contraction. Tissue concentrations of TIMP-1 and TIMP-2 in POSS treated wounds appear to coordinate the sequence of MMP events in the healing tissue. Matrix metalloproteinase-13, a marker for tissue remodeling, was not upregulated in the early wound healing cascade in either POSS or saline treated wounds at 3 or 7 days. Overall, the data suggests POSS treatment contributed to enhanced early cell migration and wound closure compared to saline treatment.

Clinical outcomes of hydrofiber foam dressing in the treatment of abrasion wounds: A retrospective study

Mopeds are a popular mode of transportation in Taiwan, yet collision accidents often lead to abrasion requiring medical attention. While hydrofiber foam dressing (HFD) have proven to help control exudates, reduce the frequency of dressing changes, and preserve more viable tissue, there is currently no established clinical guideline for the treatment of abrasion wounds with dressings. Therefore, the aim of this study was to investigate the clinical outcomes of abrasions treated with hydrofiber foam dressings. A total of 127 patients treated with HFDs between June 2018 and January 2021 were included in this study. Abrasions were categorized into 3 grades: grade I (n = 0) involving the epidermal layer, grade II (n = 89) involving the dermal layer, and grade III (n = 38) involving subcutaneous layer, bone or tendon. Statistical analysis showed that there was a significant difference in healing time (P < 0.001) and the number of outpatient department (OPD) visits (P = 0.013) between grade II and grade III. However, there was no significant difference in the number of dressing pieces used. This study offers a clinical reference for the use of hydrofiber foam dressings in treating different grades of abrasion wounds caused by moped accidents.

Small molecular exogenous modulators of active forms of MMPs

Matrix metalloproteinases (MMPs) are endopeptidases, and their activity depends on calcium and zinc metal ions. These enzymes are expressed originally in zymogenic form, where the active site of proteins is closed by a prodomain which is removed during activation. A homeostatic balance of their activity is primarily regulated by a 'cysteine switch' located on a consensus sequence of the prodomain and natural endogenous inhibitors, called tissue inhibitors of metalloproteinases (TIMPs). Breakage of this homeostasis may lead to various pathological conditions, which may require further activation and/or inhibition of these enzymes to regenerate that balance. Here, we report four modulators, more specifically, three inhibitors (I1, I2 and I3), and one exogenous activator (L) of the active form of human collagenase MMP-1 (without prodomain). The results were confirmed by binding studies using fluorescence-based enzyme assays.

Teicoplanin-Decorated Reduced Graphene Oxide Incorporated Silk Protein Hybrid Hydrogel for Accelerating Infectious Diabetic Wound Healing and Preventing Diabetic Foot Osteomyelitis

Developing hybrid hydrogel dressings with anti-inflammatory, antioxidant, angiogenetic, and antibiofilm activities with higher bone tissue penetrability to accelerate diabetic wound healing and prevent diabetic foot osteomyelitis (DFO) is highly desirable in managing diabetic wounds. Herein, the glycopeptide teicoplanin is used for the first time as a green reductant to chemically reduce graphene oxide (GO). The resulting teicoplanin-decorated reduced graphene oxide (rGO) is incorporated into a mixture of silk proteins (SP) and crosslinked with genipin to yield a physicochemically crosslinked rGO-SP hybrid hydrogel. This hybrid hydrogel exhibits high porosity, self-healing, shear-induced thinning, increased cell proliferation and migration, and mechanical properties suitable for tissue engineering. Moreover, the hybrid hydrogel eradicates bacterial biofilms with a high penetrability index in agar and hydroxyapatite disks covered with biofilms, mimicking bone tissue. In vivo, the hybrid hydrogel accelerates the healing of noninfected wounds in a diabetic rat and infected wounds in a diabetic mouse by upregulating anti-inflammatory cytokines and downregulating matrix metalloproteinase-9, promoting M2 macrophage polarization and angiogenesis. The implantation of hybrid hydrogel into the infected site of mouse tibia improves bone regeneration. Hence, the rGO-SP hybrid hydrogel can be a promising wound dressing for treating infectious diabetic wounds, providing a further advantage in preventing DFO.

Fibrosis-on-Chip: A Guide to Recapitulate the Essential Features of Fibrotic Disease

Fibrosis, which is primarily marked by excessive extracellular matrix (ECM) deposition, is a pathophysiological process associated with many disorders, which ultimately leads to organ dysfunction and poor patient outcomes. Despite the high prevalence of fibrosis, currently there exist few therapeutic options, and importantly, there is a paucity of in vitro models to accurately study fibrosis. This review discusses the multifaceted nature of fibrosis from the viewpoint of developing organ-on-chip (OoC) disease models, focusing on five key features: the ECM component, inflammation, mechanical cues, hypoxia, and vascularization. The potential of OoC technology is explored for better modeling these features in the context of studying fibrotic diseases and the interplay between various key features is emphasized. This paper reviews how organ-specific fibrotic diseases are modeled in OoC platforms, which elements are included in these existing models, and the avenues for novel research directions are highlighted. Finally, this review concludes with a perspective on how to address the current gap with respect to the inclusion of multiple features to yield more sophisticated and relevant models of fibrotic diseases in an OoC format.

4-aminopyridine attenuates inflammation and apoptosis and increases angiogenesis to promote skin regeneration following a burn injury

Severe thermal skin burns are complicated by inflammation and apoptosis, which delays wound healing and contributes to significant morbidity. Diverse treatments demonstrate limited success with mitigating these processes to accelerate healing. Agents that alter cell behavior to improve healing would alter treatment paradigms. We repurposed 4-aminopyridine (4-AP), a drug approved by the US FDA for multiple sclerosis, to treat severe burns. We found that 4-AP, in the early stages of burn healing, significantly reduced the expression of pro-inflammatory cytokines IL1β and TNFα while increasing the expression of anti-inflammatory markers CD206, ARG-1, and IL10. 4-AP attenuated apoptosis, with decreases in apoptotic markers BAX, caspase-9, and caspase-3 and increases in anti-apoptotic markers BCL2 and BCL-XL. Furthermore, 4-AP promoted angiogenesis through increases in the expression of CD31, VEGF, and eNOS. Together, these likely contributed to accelerated burn wound closure, as demonstrated in increased keratinocyte proliferation (K14) and differentiation (K10) markers. In the later stages of burn healing, 4-AP increased TGFβ and FGF levels, which are known to mark the transformation of fibroblasts to myofibroblasts. This was further demonstrated by an increased expression of α-SMA and vimentin, as well as higher levels of collagen I and III, MMP 3, and 9 in animals treated with 4-AP. Our findings support the idea that 4-AP may have a novel, clinically relevant therapeutic use in promoting burn wound healing.

Nanozyme-Incorporated Microneedles for the Treatment of Chronic Wounds

Acute wounds are converted to chronic wounds due to advanced age and diabetic complications. Nanozymes catalyze ROS production to kill bacteria without causing drug resistance, while microneedles (MNs) can break through the skin barrier to deliver drugs effectively. Nanozymes can be intergrateded into MNs delivery systems to improve painless drug delivery. It can also reduce the effective dose of drug sterilization while increasing delivery efficiency and effectively killing wounded bacteria while preventing drug resistance. This paper describes various types of metal nanozymes from previous studies and compares their mutual enhancement with nanozymes. The pooled results show that the MNs, through material innovation, are able to both penetrate the scab and deliver nanozymes and exert additional anti-inflammatory and bactericidal effects. The catalytic effect of some of the nanozymes can also accelerate the lysis of the MNs or create a cascade reaction against inflammation and infection. However, the issue of increased toxicity associated with skin penetration and clinical translation remains a challenge. This study reviews the latest published results and corresponding challenges associated with the use of MNs combined with nanozymes for the treatment of wounds, providing further information for future research.

The wound microbiota: microbial mechanisms of impaired wound healing and infection

The skin barrier protects the human body from invasion by exogenous and pathogenic microorganisms. A breach in this barrier exposes the underlying tissue to microbial contamination, which can lead to infection, delayed healing, and further loss of tissue and organ integrity. Delayed wound healing and chronic wounds are associated with comorbidities, including diabetes, advanced age, immunosuppression and autoimmune disease. The wound microbiota can influence each stage of the multi-factorial repair process and influence the likelihood of an infection. Pathogens that commonly infect wounds, such as Staphylococcus aureus and Pseudomonas aeruginosa, express specialized virulence factors that facilitate adherence and invasion. Biofilm formation and other polymicrobial interactions contribute to host immunity evasion and resistance to antimicrobial therapies. Anaerobic organisms, fungal and viral pathogens, and emerging drug-resistant microorganisms present unique challenges for diagnosis and therapy. In this Review, we explore the current understanding of how microorganisms present in wounds impact the process of skin repair and lead to infection through their actions on the host and the other microbial wound inhabitants.

Bringing back Galium aparine L. from forgotten corners of traditional wound treatment procedures: an antimicrobial, antioxidant, and in-vitro wound healing assay along with HPTLC fingerprinting study

BACKGROUND

The wound healing process, restoring the functionality of the damaged tissue, can be accelerated by various compounds. The recent experimental analysis highlights the beneficial effects of phytochemicals in improving skin regeneration and wound healing. In traditional medicine, one of the widespread plants used for treating different injuries or skin afflictions is Galium aparine L. (GA). Besides, previously reported chemical compounds of GA suggested its therapeutic effects for the wound healing process, yet its regulatory effects on the cellular and molecular stages of the wound healing process have not been investigated.

METHODS

In the present study, the phytochemical profile of the GA extract was analyzed using HPTLC fingerprinting, and further scientific evaluation of its phytochemicals was done. The wound-healing effects of GA extract were explored at the cellular and molecular levels while accounting for cell toxicity. The wound closure enhancing effect, antibacterial activity, and antioxidant activity were assessed.

RESULTS

The HPTLC fingerprinting of the GA extract proved its previously reported phytochemical profile including phenols, flavonoids, tannins, plant acids, ergot alkaloids, flavonoids, anthraquinones, terpenoids, sterols, salicin, lipophilic compounds, saponins, iridoids, and heterocyclic nitrogen compounds. Antimicrobial assessment, of the extract, indicated the more susceptibility of S. aureus to the inhibitory effects of GA rather than E. coli and S. epidermidis. DPPH test results revealed the antioxidant property of GA extract, which was comparable to ascorbic acid. The results of the viability assay showed no cytotoxicity effects on human umbilical endothelial cell (HUVEC) and normal human dermal fibroblast (NHDF) cell lines treated with different concentrations of whole plant extract and cell viability increased in a dose-dependent manner. The results of the scratch assay showed improved cell migration and wound closure.

CONCLUSIONS

This study shows the anti-oxidant, anti-microbial, and in vitro wound healing wound-healing effects of GA hydroalcoholic extract, which aligns with its use in traditional medicine. No cytotoxicity effects were shown. The results from this study can be the basis for further investigations such as animal models and phytochemical studies. Further evaluation of its effects on mechanisms and signaling pathways involved in the wound healing processes such as angiogenesis and cell proliferation can provide novel insights into the potential therapeutic effects of the GA extract.

Design Strategy of Microneedle Systems for Skin Wound Healing: Based on the Structure of Tips and Therapeutic Methodologies

The skin, being the largest organ of the human body, is susceptible to damage resulting in wounds that are vulnerable to pathogenic attacks and fail to provide effective protection for internal tissues. Therefore, it is crucial to expedite wound healing. In recent years, microneedles have garnered significant attention as an innovative drug delivery system owing to their noninvasive and painless administration, simplified application process, precise control over drug release, and versatile loading capabilities. Consequently, they hold immense potential for the treatment of skin wound. This review presents a comprehensive design strategy for the microneedle system in promoting skin wound healing. First, the process of skin wound healing and the characteristics of specific wounds are elucidated. The design strategies for microneedles are subsequently presented and classified based on their structural and therapeutic methodologies. Finally, a succinct recapitulation of the previously discussed points and a prospective analysis are provided.

The Categorization of Perinatal Derivatives for Orthopedic Applications

Musculoskeletal (MSK) pathology encompasses an array of conditions that can cause anything from mild discomfort to permanent injury. Their prevalence and impact on disability have sparked interest in more effective treatments, particularly within orthopedics. As a result, the human placenta has come into focus within regenerative medicine as a perinatal derivative (PnD). These biologics are sourced from components of the placenta, each possessing a unique composition of collagens, proteins, and factors believed to aid in healing and regeneration. This review aims to explore the current literature on PnD biologics and their potential benefits for treating various MSK pathologies. We delve into different types of PnDs and their healing effects on muscles, tendons, bones, cartilage, ligaments, and nerves. Our discussions highlight the crucial role of immune modulation in the healing process for each condition. PnDs have been observed to influence the balance between anti- and pro-inflammatory factors and, in some cases, act as biologic scaffolds for tissue growth. Additionally, we assess the range of PnDs available, while also addressing gaps in our understanding, particularly regarding biologic processing methods. Although certain PnD biologics have varying levels of support in orthopedic literature, further clinical investigations are necessary to fully evaluate their impact on human patients.

Evaluation of wound healing and anti-inflammatory activity of hydro-alcoholic extract and solvent fractions of the leaves of Clerodendrum myricoides (Lamiaceae) in mice

BACKGROUND

Wounds significantly affect people's quality of life and the clinical and financial burden of healthcare systems around the world. Many of the current drugs used to treat wounds have problems such as; allergies and drug resistance. Hence, the exploration of new therapeutic agents from natural origin may avert this problem. Clerodendrum myricoides have long been used to treat wounds in Ethiopia. Despite this, nothing has so far been reported about the wound healing and anti-inflammatory activity of C. myricoides. This study aimed to evaluate the wound healing and anti-inflammatory activity of 80% methanol extract and solvent fractions of C. myricoides leaves in mice.

METHODS

Leaves of C. myricoides were extracted using the maceration technique. The extract was formulated as 5% and 10% w/w ointments. The wound healing activity of the extract was evaluated using excision, incision, and burn wound models whereas the healing activities of solvent fractions were evaluated using the excision wound model. A carrageenan-induced paw edema model was used for the anti-inflammatory test.

RESULTS

In the dermal toxicity test, 2000 mg/kg of 10% extract was found to be safe. In excision and burn wound models, treatment with 10% and 5% extract showed a significant (p<0.001) wound contraction. Solvent fractions of the extract significantly reduced wound contraction. A significant reduction in periods of epithelialization and favorable histopathology changes were shown by extract ointments. In incision wounds, 10% (p<0.001) and 5% (p<0.01) extracts significantly increase skin-breaking strength. After one hour of treatment, 400 mg/kg (p<0.001) and 200 mg/kg (p<0.05) showed significant reduction in paw edema.

CONCLUSION

Results of this study indicate that 80% methanol extract and the solvent fraction of the leaves of C. myricoides possess wound-healing and anti-inflammatory activity and support traditional claims.

Combined use of hydrogen-rich water and enzyme-digested edible bird's nest improves PMA/LPS-impaired wound healing in human inflammatory gingival tissue equivalents

Gingival wound healing plays a critical role in maintaining oral health. However, this process can be delayed by oxidative stress and excessive inflammatory responses. In this study, we established a human inflammatory gingival tissue equivalent (iGTE) to investigate the inhibitory effects of hydrogen-rich water (HW), enzyme-digested edible bird's nest (EBND) and sialic acid (SA) on PMA (an inducer of oxidative free radicals)- and LPS (an inflammatory stimulus)-impaired wound healing. The iGTE was constructed by human gingival fibroblasts (hGFs), keratinocytes and macrophages under three-dimensional conditions. Wounds in the iGTE and hGF/keratinocyte monolayers were created by mechanical injury. Tissues and cells were pretreated with HW, EBND, and SA, and then exposed to the inflammatory and oxidative environment induced by PMA (10 ng/mL) and LPS (250 ng/mL). The inflammatory cytokines IL-6 and IL-8 were quantitatively analyzed by ELISA. Histopathological image analysis was performed by HE and immunofluorescence staining. In the iGTE, PMA/LPS significantly reduced the epithelial thickness while causing a decrease in K8/18, E-cadherin, laminin and elastin expression and an increase in COX-2 expression along with ulcer-like lesions. In mechanically scratched hGFs and keratinocyte monolayers, PMA/LPS significantly impaired wound healing, and promoted the secretion of IL-6 and IL-8. Pretreatment of HW, EBND, and SA significantly suppressed PMA/LPS-induced wound healing delay and inflammatory responses in cell monolayers, as well as in the iGTE. Remarkably, the combined use of HW and EBND exhibited particularly robust results. Combined use of HW and EBND may be applied for the prevention and treatment of wound healing delay.

Low-temperature plasma jet suppresses bacterial colonisation and affects wound healing through reactive species

An argon-based low-temperature plasma jet (LTPJ) was used to treat chronically infected wounds in Staphylococcus aureus-laden mice. Based on physicochemical property analysis and in vitro antibacterial experiments, the effects of plasma parameters on the reactive nitrogen and oxygen species (RNOS) content and antibacterial capacity were determined, and the optimal treatment parameters were determined to be 4 standard litre per minute and 35 W. Additionally, the plasma-treated activation solution had a bactericidal effect. Although RNOS are related to the antimicrobial effect of plasma, excess RNOS may be detrimental to wound remodelling. In vivo studies demonstrated that medium-dose LTPJ promoted MMP-9 expression and inhibited bacterial growth during the early stages of healing. Moreover, LTPJ increased collagen deposition, reduced inflammation, and restored blood vessel density and TGF-β levels to normal in the later stages of wound healing. Therefore, when treating chronically infected wounds with LTPJ, selecting the medium dose of plasma is more advantageous for wound recovery. Overall, our study demonstrated that low-temperature plasma jets may be a potential tool for the treatment of chronically infected wounds.

Porous silicon-based sensing and delivery platforms for wound management applications

Wound management remains a great challenge for clinicians due to the complex physiological process of wound healing. Porous silicon (PSi) with controlled pore morphology, abundant surface chemistry, unique photonic properties, good biocompatibility, easy biodegradation and potential bioactivity represent an exciting class of materials for various biomedical applications. In this review, we focus on the recent progress of PSi in the design of advanced sensing and delivery systems for wound management applications. Firstly, we comprehensively introduce the common type, normal healing process, delaying factors and therapeutic drugs of wound healing. Subsequently, the typical fabrication, functionalization and key characteristics of PSi have been summarized because they provide the basis for further use as biosensing and delivery materials in wound management. Depending on these properties, the rise of PSi materials is evidenced by the examples in literature in recent years, which has emphasized the robust potential of PSi for wound monitoring, treatment and theranostics. Finally, challenges and opportunities for the future development of PSi-based sensors and delivery systems for wound management applications are proposed and summarized. We hope that this review will help readers to better understand current achievements and future prospects on PSi-based sensing and delivery systems for advanced wound management.

Baeckea frutescens L. Promotes wound healing by upregulating expression of TGF-β, IL-1 β, VEGF and MMP-2

Baeckea frutescens L. has been traditionally used for treating snakebites and is known to possess antifebrile and hemostatic properties. These properties are closely related to wound healing. This study aimed to evaluate the wound healing properties of B. frutescens leaves extract (BFLE) in vitro and in vivo. The in vitro study focused on proliferation, migration, and expression of TGF-β, IL-1β, VEGF, and MMP-2 genes and proteins. The in vivo study included excisional wound healing, histology, and tensile strength studies. The ethanolic extract of B. frutescens (BFLE) was tested for its effects on proliferation and migration using keratinocytes (HaCaT) and fibroblasts (BJ) cells. Gene and protein expression related to wound healing were analyzed using real-time PCR and Western blot assays. The wound healing properties of BFLE were evaluated in vivo using Wistar albino rats, focusing on excisional wound healing, histology, and tensile strength studies. The BFLE displayed significant proliferative and migratory effects on keratinocytes and fibroblasts cells, while upregulating the expression of TGF-β, IL-1β, VEGF, and MMP-2 genes and proteins. BFLE also exhibited significant wound healing effects on Wistar albino rats' excisional wounds and improved the overall tensile strength. The results suggest that BFLE has strong wound healing properties, as demonstrated by its ability to increase keratinocytes and fibroblasts proliferation and migration, upregulate genes and proteins involved in the wound healing process, and improve wound healing rates and tensile strength. The findings of this study provide important insights into the potential use of B. frutescens as a natural wound healing agent.

Modulation of gene expression in skin wound healing by photobiomodulation therapy: A systematic review in vivo studies

BACKGROUND

Wound healing is a multistep process involving coordinated responses of a variety of cell types, cytokines, growth factors, and extracellular matrix (ECM) components leading to the physiological restoration of tissue integrity. Photobiomodulation therapy (PBMT) has been highlighted as an approach to improve the healing process, nonetheless at the molecular level, the effects of PBMT are not entirely understood.

AIM

To systematically review publications that investigated gene expression after PBMT during in vivo skin repair.

METHODS

An electronic search was undertaken in Medline Ovid (Wolters Kluwer), PubMed (National Library of Medicine), Web of Science (Thomson Reuters), Scopus (Elsevier), Embase, and LILACS databases. The search strategy was conducted from the terms: low-level light therapy, gene expression, and wound healing and their synonyms. The databases were consulted in December 2023 and no publication year limit was used.

RESULTS

Eleven studies were included in this review and the expression of 186 genes was evaluated. PBMT modified the expression of several targets genes studied, such as down-regulation of genes related to extracellular matrix proteases (MMP2 and MMP9) and pro-inflammatory cytokines (IL10 and IL6) and up-regulation of DNMT3A and BFGF.

CONCLUSION

This review demonstrates that PBMT is capable of regulating gene expression during wound healing. Most evidence showed a positive impact of PBMT in regulating genes linked to inflammatory cytokines improving skin wound healing. Yet, the effects of PBMT in genes involved in other mechanisms still need to be better understood.

Extracellular Vesicles Derived from Opuntia ficus-indica Fruit (OFI-EVs) Speed Up the Normal Wound Healing Processes by Modulating Cellular Responses

Plant-derived extracellular vesicles (EVs) have been recognized as important mediators of intercellular communication able to transfer active biomolecules across the plant and animal kingdoms. EVs have demonstrated an impressive array of biological activities, displaying preventive and therapeutic potential in mitigating various pathological processes. Indeed, the simplicity of delivering exogenous and endogenous bioactive molecules to mammalian cells with their low cytotoxicity makes EVs suitable agents for new therapeutic strategies for a variety of pathologies. In this study, EVs were isolated from Opuntia ficus-indica fruit (OFI-EVs) and characterized by particle size distribution, concentration, and bioactive molecule composition. OFI-EVs had no obvious toxicity and demonstrated a protective role in the inflammatory process and oxidative stress in vitro model of chronic skin wounds. The results demonstrated that pretreatment with OFI-EVs decreased the activity and gene expression of pro-inflammatory cytokines (IL-6, IL-8, and TNF-α) in the LPS-stimulated human leukemia monocytic cell line (THP-1). Furthermore, OFI-EVs promote the migration of human dermal fibroblasts (HDFs), speeding up the normal wound healing processes. This study sheds light, for the first time, on the role of OFI-EVs in modulating important biological processes such as inflammation and oxidation, thereby identifying EVs as potential candidates for healing chronic cutaneous wounds.

Differences in metalloproteinases and their tissue inhibitors in the cerebrospinal fluid are associated with delirium

BACKGROUND

The aetiology of delirium is not known, but pre-existing cognitive impairment is a predisposing factor. Here we explore the associations between delirium and cerebrospinal fluid (CSF) levels of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs), proteins with important roles in both acute injury and chronic neurodegeneration.

METHODS

Using a 13-plex Discovery Assay®, we quantified CSF levels of 9 MMPs and 4 TIMPs in 280 hip fracture patients (140 with delirium), 107 cognitively unimpaired individuals, and 111 patients with Alzheimer's disease dementia. The two delirium-free control groups without acute trauma were included to unravel the effects of acute trauma (hip fracture), dementia, and delirium.

RESULTS

Here we show that delirium is associated with higher levels of MMP-2, MMP-3, MMP-10, TIMP-1, and TIMP-2; a trend suggests lower levels of TIMP-4 are also associated with delirium. Most delirium patients had pre-existing dementia and low TIMP-4 is the only marker associated with delirium in adjusted analyses. MMP-2, MMP-12, and TIMP-1 levels are clearly higher in the hip fracture patients than in both control groups and several other MMP/TIMPs are impacted by acute trauma or dementia status.

CONCLUSIONS

Several CSF MMP/TIMPs are significantly associated with delirium in hip fracture patients, but alterations in most of these MMP/TIMPs could likely be explained by acute trauma and/or pre-fracture dementia. Low levels of TIMP-4 appear to be directly associated with delirium, and the role of this marker in delirium pathophysiology should be further explored.

Metalloproteins structural and functional insights into immunological patterns

Metalloproteins play a crucial role in regulating different aspects of the immune system in humans. They have various functions in immunity, including recognizing and presenting antigens, aiding in the movement and effectiveness of immune cells, and facilitating interactions between the host and pathogens. Understanding how these proteins work can help us develop new methods to control the immune response in different diseases. Metalloproteins contain metal ions in their structure, which allows them to perform these diverse functions. They encompass a wide range of enzymes, signaling molecules, and structural proteins that utilize metal ions as cofactors for their activities. Examples of metalloproteins include superoxide dismutase, catalase, and metalloproteases, which regulate oxidative stress, inflammation, and tissue remodelling processes associated with immune activation. By studying their functions and the effects of their dysfunction, researchers can develop strategies to improve immune function and combat various diseases. This review explores the diverse functions of metalloproteins in immune processes, highlighting their significance in both health and disease.

Spaceflight induces changes in gene expression profiles linked to insulin and estrogen

Organismal adaptations to spaceflight have been characterized at the molecular level in model organisms, including Drosophila and C. elegans. Here, we extend molecular work to energy metabolism and sex hormone signaling in mice and humans. We found spaceflight induced changes in insulin and estrogen signaling in rodents and humans. Murine changes were most prominent in the liver, where we observed inhibition of insulin and estrogen receptor signaling with concomitant hepatic insulin resistance and steatosis. Based on the metabolic demand, metabolic pathways mediated by insulin and estrogen vary among muscles, specifically between the soleus and extensor digitorum longus. In humans, spaceflight induced changes in insulin and estrogen related genes and pathways. Pathway analysis demonstrated spaceflight induced changes in insulin resistance, estrogen signaling, stress response, and viral infection. These data strongly suggest the need for further research on the metabolic and reproductive endocrinologic effects of space travel, if we are to become a successful interplanetary species.

Cassia alata and Its Phytochemicals: A Promising Natural Strategy in Wound Recovery

Cassia alata, a traditional herb with a global presence, is renowned for its anti-inflammatory, antibacterial, and antifungal properties, making it a go-to remedy for skin ailments. While it has demonstrated wound healing capabilities in both in vitro and in vivo studies, the precise mechanisms remain elusive. This review aims to highlight its key phytochemicals, their effects, and the mechanism of action. The compounds that have been reviewed and discussed include kaempferol, apigenin, quercetin, rhein, and rutin. These polyphenols play important roles in normal and impaired wound healing processes, encompassing hemostasis, inflammation, proliferation, and tissue remodeling.

Optimizing mesenchymal stem cell extracellular vesicles for chronic wound healing: Bioengineering, standardization, and safety

Chronic wounds represent a significant global burden, afflicting millions with debilitating complications. Despite standard care, impaired healing persists due to factors like persistent inflammation and impaired tissue regeneration. Mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) offer an innovative regenerative medicine approach, delivering stem cell-derived therapeutic cargo in engineered nanoscale delivery systems. This review examines pioneering bioengineering strategies to engineer MSC-EVs into precision nanotherapeutics for chronic wounds. Emerging technologies like CRISPR gene editing, microfluidic manufacturing, and biomimetic delivery systems are highlighted for their potential to enhance MSC-EV targeting, optimize therapeutic cargo enrichment, and ensure consistent clinical-grade production. However, key hurdles remain, including batch variability, rigorous safety assessment for potential tumorigenicity, immunogenicity, and biodistribution profiling. Crucially, collaborative frameworks harmonizing regulatory science with bioengineering and patient advocacy hold the key to expediting global clinical translation. By overcoming these challenges, engineered MSC-EVs could catalyze a new era of off-the-shelf regenerative therapies, restoring hope and healing for millions afflicted by non-healing wounds.

Topical Adipose Mesenchymal Stem cell metabolites regulate the expression of MMP-1, MMP-9, EGF, TGF-β in oral mucosa ulcer rat model

Objective

Matrix metalloproteinase (MMP-1 and -9), Epidermal Growth Factor (EGF), and Transforming Growth factor (TGF)-β are expressed in the oral ulcer wound-healing process. The Adipose mesenchymal stem cell metabolites (AdMSCMs) may accelerate wound-healing. This study aimed to investigate the expression of MMP-1, MMP-9, EGF, and TGF-β in the oral mucosa ulcer rat model treated with topical AdMSCMs.

Materials and Methods

Oral ulcer models were created in twenty healthy male Wistar rats (Rattus novergicus) divided into AdMSCMs and control groups. The oral ulcer model was treated topically using AdMSCMs oral gel three times daily for 3 and 7 days. The expression of MMP-1, MMP-9, EGF, TGF-β was evaluated through histological examination using the immunohistochemistry method. Independent t-test was used to compare the mean of expression of MMP-1, MMP-9, EGF, TGF-β between control and treatment groups (AdMSCMs), and paired t-test was used to analyze the mean between day 3 and day 7 of each group.

Results

A lower expression of MMP-1, MMP-9 in AdMSCMs group and higher expression EGF and TGF-β in AdMSCMs group compared to the control group in day 3 and day 7. Independent t-test results showed a significant difference in the expression of MMP-1, MMP-9, EGF between the control and AdMSCMs group in day 3 and day 7. Only TGF-β expression mean difference between day 3 and day 7 showed a significant difference compared to the control groups (p < 0.05).

Conclusions

AdMSCMs oral gel may accelerate oral ulcer healing models by reducing the expression MMP-1, MMP-9, and increasing EGF and TGF-β expressions during the wound-healing process.

Recent advancements in natural polymers-based self-healing nano-materials for wound dressing

The field of wound healing has witnessed remarkable progress in recent years, driven by the pursuit of advanced wound dressings. Traditional dressing materials have limitations like poor biocompatibility, nonbiodegradability, inadequate moisture management, poor breathability, lack of inherent therapeutic properties, and environmental impacts. There is a compelling demand for innovative solutions to transcend the constraints of conventional dressing materials for optimal wound care. In this extensive review, the therapeutic potential of natural polymers as the foundation for the development of self-healing nano-materials, specifically for wound dressing applications, has been elucidated. Natural polymers offer a multitude of advantages, possessing exceptional biocompatibility, biodegradability, and bioactivity. The intricate engineering strategies employed to fabricate these polymers into nanostructures, thereby imparting enhanced mechanical robustness, flexibility, critical for efficacious wound management has been expounded. By harnessing the inherent properties of natural polymers, including chitosan, alginate, collagen, hyaluronic acid, and so on, and integrating the concept of self-healing materials, a comprehensive overview of the cutting-edge research in this emerging field is presented in the review. Furthermore, the inherent self-healing attributes of these materials, wherein they exhibit innate capabilities to autonomously rectify any damage or disruption upon exposure to moisture or body fluids, reducing frequent dressing replacements have also been explored. This review consolidates the existing knowledge landscape, accentuating the benefits and challenges associated with these pioneering materials while concurrently paving the way for future investigations and translational applications in the realm of wound healing.

Topical application of a hyaluronic acid-based hydrogel integrated with secretome of human mesenchymal stromal cells for diabetic ulcer repair

This preclinical proof-of-concept study aimed to evaluate the effectiveness of secretome therapy in diabetic mice with pressure ulcers. We utilized a custom-made hyaluronic acid (HA)-based porous sponge, which was rehydrated either with normal culture medium or secretome derived from human mesenchymal stromal cells (MSCs) to achieve a hydrogel consistency. Following application onto skin ulcers, both the hydrogel-only and the hydrogel + secretome combination accelerated wound closure compared to the vehicle group. Notably, the presence of secretome significantly enhanced the healing effect of the hydrogel, as evidenced by a thicker epidermis and increased revascularization of the healed area compared to the vehicle group. Notably, molecular analysis of healed skin revealed significant downregulation of genes involved in delayed wound healing and abnormal inflammatory response in ulcers treated with the hydrogel + secretome combination, compared to those treated with the hydrogel only. Additionally, we found no significant differences in therapeutic outcomes when comparing the use of secretome from fetal dermal MSCs to that from umbilical cord MSCs. This observation is supported by the proteomic profile of the two secretomes, which suggests a shared molecular signature responsible of the observed therapeutic effects.

Development of alginate and alginate sulfate/polycaprolactone nanoparticles for growth factor delivery in wound healing therapy

Connective tissue growth factor (CTGF) holds great promise for enhancing the wound healing process; however, its clinical application is hindered by its low stability and the challenge of maintaining its effective concentration at the wound site. Herein, we developed novel double-emulsion alginate (Alg) and heparin-mimetic alginate sulfate (AlgSulf)/polycaprolactone (PCL) nanoparticles (NPs) for controlled CTGF delivery to promote accelerated wound healing. The NPs' physicochemical properties, cytocompatibility, and wound healing activity were assessed on immortalized human keratinocytes (HaCaT), primary human dermal fibroblasts (HDF), and a murine cutaneous wound model. The synthesized NPs had a minimum hydrodynamic size of 200.25 nm. Treatment of HaCaT and HDF cells with Alg and AlgSulf2.0/PCL NPs did not show any toxicity when used at concentrations <50 µg/mL for up to 72 h. Moreover, the NPs' size was not affected by elevated temperatures, acidic pH, or the presence of a protein-rich medium. The NPs have slow lysozyme-mediated degradation implying that they have an extended tissue retention time. Furthermore, we found that treatment of HaCaT and HDF cells with CTGF-loaded Alg and AlgSulf2.0/PCL NPs, respectively, induced rapid cell migration (76.12% and 79.49%, P<0.05). Finally, in vivo studies showed that CTGF-loaded Alg and AlgSulf2.0/PCL NPs result in the fastest and highest wound closure at the early and late stages of wound healing, respectively (36.49%, P<0.001 on day 1; 90.45%, P<0.05 on day 10), outperforming free CTGF. Double-emulsion NPs based on Alg or AlgSulf represent a viable strategy for delivering heparin-binding GF and other therapeutics, potentially aiding various disease treatments.

Skin wound healing in diabetic rat model using low-dose photodynamic therapy

Chronic wound is one of the major challenges in medicine and imposes a heavy financial burden on the healthcare of different countries. Diabetic foot ulcers as one of the important examples for chronic wounds can lead to lower limb amputation, disability, and death in diabetics. In this regard, novel technology with low side effects got attention in recent years. Low-dose photodynamic therapy (LDPDT) is one of the noninvasive techniques that can be considered for wound healing in diabetic wounds. In this experiment, we aim to study the effect of LDPDT on diabetic rats' wound healing and compare it to healthy rats. In this in vitro experimental study, 32 male rats were used. Rats in both normal and diabetic (streptozotocin injection) groups after being wounded (two wounds [0.8 × 0.8 cm]) on the back of each rat were randomly divided into four groups, including the control group (without treatment), radiation-only (660 nm-1 J/cm2) group, 5-ALA-only (1 µg/mL) group, and LDPDT-recipient group. The procedure has been done for 2 days, and at the end of Days 3, 7, 14, and 21, the wound sample was sent to the histopathology laboratory, and the wound size and tissue indices in these groups were evaluated by histology and microscopy techniques. The impact of low concentrations of 5-ALA and low irradiation energy density in both normal and diabetic rats were positive, which accelerated the wound-healing process as seen in the histology study. In diabetic rats treated with only radiation and LDPDT, the process of epithelial regeneration, collagen production, reduction of mast cells, and production of follicles was more as compared to the normal group. The results suggest that LDPDT can have a positive impact on the diabetic rat model wound healing.

Preparation and characterization of PVA/chitosan nanofibers loaded with Dragon's blood or poly helixan as wound dressings

Nanofibers have been investigated in regenerative medicine. Dragon's blood (DB)- and poly helixan PF (PHPF) are natural materials used in cosmetics. Herein, we generated DB- and PHPF-loaded polyvinyl alcohol/chitosan (PVA/CS/DB and PVA/CS/PHPF, respectively) nanofibers. PVA/CS/DB and PVA/CS/PHPF nanofibers had an average diameter of 547.5 ± 17.13 and 521 ± 24.67 nm, respectively as assessed by SEM, and a degradation rate of 43.1 and 47.6 % after 14 days, respectively. PVA/CS/DB and PVA/CS/PHPF nanofibers had a hemolysis rate of 0.10 and 0.39 %, respectively, and a water vapor transmission rate of ∼2200 g.m-2.day-1. These nanofibers exhibited favorable antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis in vitro. PVA/CS/DB and PVA/CS/PHPF nanofibers demonstrated a sustained release of 77.91 and 76.55 % over 72 h. PVA/CS/DB and PVA/CS/PHPF nanofibers had a high rate of cytocompatibility and significantly improved the viability of NIH/3T3 cells as compared with free drugs or unloaded nanofibers. Histological inspection via H&E and Verhoeff's staining demonstrated PVA/CS/DB and PVA/CS/PHPF nanofibers enhanced the wound healing and damaged tissue recovery of unsplinted wound models by promoting epithelial layer formation, collagen deposition, and enhancing the presence of fibroblasts. Conclusively, PVA/CS/DB and PVA/CS/PHPF can be introduced as potential wound dressing candidates with favorable properties.

The epithelial adherens junction component PLEKHA7 regulates ECM remodeling and cell behavior through miRNA-mediated regulation of MMP1 and LOX

Epithelial adherens junctions (AJs) are cell-cell adhesion complexes that are influenced by tissue mechanics, such as those emanating from the extracellular matrix (ECM). Here, we introduce a mechanism whereby epithelial AJs can also regulate the ECM. We show that the AJ component PLEKHA7 regulates levels and activity of the key ECM remodeling components MMP1 and LOX in well-differentiated colon epithelial cells, through the miR-24 and miR-30c miRNAs. PLEKHA7 depletion in epithelial cells results in LOX-dependent ECM remodeling in culture and in the colonic mucosal lamina propria in mice. Furthermore, PLEKHA7-depleted cells exhibit increased migration and invasion rates that are MMP1- and LOX- dependent, and form colonies in 3D cultures that are larger in size and acquire aberrant morphologies in stiffer matrices. These results reveal an AJ-mediated mechanism, through which epithelial cells drive ECM remodeling to modulate their behavior, including acquisition of phenotypes that are hallmarks of conditions such as fibrosis and tumorigenesis.