Human saliva stimulates skin and oral wound healing in vitro

Developmental prospects of carrageenan-based wound dressing films: Unveiling techno-functional properties and freeze-drying technology for the development of absorbent films - A review

This review explores the intricate wound healing process, emphasizing the critical role of dressing material selection, particularly for chronic wounds with high exudate levels. The aim is to tailor biodegradable dressings for comprehensive healing, focusing on maximizing moisture retention, a vital element for adequate recovery. Researchers are designing advanced wound dressings that enhance techno-functional and bioactive properties, minimizing healing time and ensuring cost-effective care. The study delves into wound dressing materials, highlighting carrageenan biocomposites superior attributes and potential in advancing wound care. Carrageenan's versatility in various biomedical applications demonstrates its potential for tissue repair, bone regeneration, and drug delivery. Ongoing research explores synergistic effects by combining carrageenan with other novel materials, aiming for complete biocompatibility. As innovative solutions emerge, carrageenan-based wound-healing medical devices are poised for global accessibility, addressing challenges associated with the complex wound-healing process. The exceptional physico-mechanical properties of carrageenan make it well-suited for highly exudating wounds, offering a promising avenue to revolutionize wound care through freeze-drying techniques. This thorough approach to evaluating the wound healing effectiveness of carrageenan-based films, particularly emphasizing the development potential of lyophilized films, has the potential to significantly improve the quality of life for patients receiving wound healing treatments.

Collagen: The Superior Material for Full-Thickness Oral Mucosa Tissue Engineering

BACKGROUND

Tissue engineering has significantly progressed in developing full-thickness oral mucosa constructs designed to replicate the natural oral mucosa. These constructs serve as valuable in vitro models for biocompatibility testing and oral disease modeling and hold clinical potential for replacing damaged or lost oral soft tissue. However, one of the major challenges in tissue engineering of the oral mucosa is the identification of an appropriate scaffold with optimal porosity, interconnected porous networks, biodegradability, and biocompatibility. These characteristics facilitate cell migration, nutrient delivery, and vascularization. Various biomaterials have been investigated for constructing tissue-engineered oral mucosa models; collagen has demonstrated superior outcomes compared with other materials.

HIGHLIGHT

This review discusses the different types of tissue-engineered oral mucosa developed using various materials and includes articles published between January 2000 and December 2022 in PubMed and Google Scholar. The review focuses on the superiority of collagen-based scaffolds for tissue engineering of oral mucosa, explores in vitro applications, and discusses potential clinical applications.

CONCLUSION

Among the various scaffold materials used for engineering the connective tissue of the oral mucosa, collagen-based scaffolds possess excellent biological properties, offering high-quality oral mucosa constructs and high resemblance to the native human oral mucosa in terms of histology and expression of various differentiation markers.

Nature-Inspired Scarless Healing: Guiding Biomaterials Design for Advanced Therapies

The use of biomaterials in the treatment of skin wounds has been steadily increasing over the last two decades. The key to the successful application of biomaterials in scar reduction is the up-to-date knowledge of the actors involved in accelerated healing and the cellular factors that can be implemented in bioinspired materials. Natural models of scarless healing such as oral mucosa, fetal skin and the skin of amphibians, fish, and reptiles are a great source of information. By investigating their microenvironments, cellular factors, and inflammatory self-regulatory systems, a general model of scarless healing can be defined. This review introduces the basic and current concepts of skin wound healing and focuses on providing a detailed overview of the main processes of accelerated healing without scarring. The article outlines the common features and key points that develop and promote scar-free healing. The tissues and healing processes of the selected natural models are described individually (tissue organization, structural components, ratios of cellular factors such as Collagen and transforming growth factor and their mechanisms of regulation of inflammation and scar overgrowth). A comparative work of each natural model concerning healing in human skin is included in the discussion. Finally, the patterns identified through the analysis of each model and their differences from normal healing are presented to facilitate the knowledge for the implementation of new treatments.

Novel Functional Dressing Materials for Intraoral Wound Care

Intraoral wounds represent a particularly challenging category of mucosal and hard tissue injuries, characterized by the unique structures, complex environment, and distinctive healing processes within the oral cavity. They have a common occurrence yet frequently inflict significant inconvenience and pain on patients, causing a serious decline in the quality of life. A variety of novel functional dressings specifically designed for the moist and dynamic oral environment have been developed and realized accelerated and improved wound healing. Thoroughly analyzing and summarizing these materials is of paramount importance in enhancing the understanding and proficiently managing intraoral wounds. In this review, the particular processes and unique characteristics of intraoral wound healing are firstly described. Up-to-date knowledge of various forms, properties, and applications of existing products are then intensively discussed, which are categorized into animal products, plant extracts, natural polymers, and synthetic products. To conclude, this review presents a comprehensive framework of currently available functional intraoral wound dressings, with an aim to provoke inspiration of future studies to design more convenient and versatile materials.

Periplaneta americana extract promotes hard palate mucosal wound healing via the PI3K/AKT signaling pathway in male mice

OBJECTIVES

This study aimed to investigate the effect of Periplaneta americana extract, a traditional Chinese medicine, on hard palate mucosal wound healing and explore the underlying mechanisms.

DESIGN

Hard palate mucosal wound model was established and the effects of Periplaneta americana extract on hard palate mucosal wound healing were investigated by stereomicroscopy observation and histological evaluation in vivo. Human oral keratinocytes and human gingival fibroblasts, which play key roles in hard palate mucosal wound healing, were selected as the main research cells in vitro. The effects of Periplaneta americana extract on cell proliferation, migration, and collagen formation were determined by cell counting kit-8 (CCK-8) assay, Transwell assay, and Van Gieson staining. The underlying mechanism was revealed by RNA sequencing, and results were verified by western blot assay.

RESULTS

Stereomicroscopy observation and H&E staining confirmed that Periplaneta americana extract accelerated the healing rate of hard palate mucosal wound (p < 0.001) in vivo. Transwell assay and Van Gieson staining assay showed that Periplaneta americana extract promoted the migration and collagen formation of human oral keratinocytes (p < 0.001) and human gingival fibroblasts (p < 0.001) in vitro. Mechanistically, RNA sequencing and western blot assay demonstrated that Periplaneta americana extract promoted hard palate mucosal wound healing via PI3K/AKT signaling, and the beneficial effects of Periplaneta americana extract were abrogated by the PI3K inhibitor LY294002.

CONCLUSIONS

Periplaneta americana extract shows promising effects for the promotion of hard palate mucosal wound healing and may be a novel candidate for clinical translation.

Transnasal negative pressure therapy for accelerating healing and improving the prognosis of pharyngocutaneous fistula

BACKGROUND

Pharyngocutaneous fistula (PCF) is one of the most common complications of total laryngectomy. This study is to investigate the efficacy of a novel platform called transnasal negative pressure therapy (TNPT) in the management of PCF.

METHODS

We retrospectively reviewed 47 patients who underwent total laryngectomy between April 2015 and February 2021 and developed PCF in our hospital. We focused on the healing rate, dressing change frequency, and healing time between the TNPT and non-TNPT groups. The 2 years overall survival (OS) was compared through the log-rank test.

RESULTS

There were 18 patients in the TNPT group and 29 in the non-TNPT group. There was no significant between-group difference in the healing rate (chi-square test). However, the frequency of dressing changes was significantly lower (p < 0.001) and the healing time was significantly shorter (p = 0.0194) in the TNPT group than in the non-TNPT group. The 2-year OS rate was significantly higher in the TNPT group (p = 0.0473, log-rank test).

CONCLUSION

TNPT promoted wound healing after surgery for PCF and improved the 2-year OS rate. This tool is worthy of clinical application and promotion.

Inflammation-related proteomics demonstrate landscape of fracture blister fluid in patients with acute compartment syndrome

Background

Blisters are tense vesicles or bullae that arise on swollen skin and are found in a wide range of injuries. As a complication of fracture, fracture blisters are considered soft tissue injuries, which often lead to adverse effects such as prolonged preoperative waiting time and increased risk of surgical site infection. However, our previous study found that in patients with acute compartment syndrome, fracture blisters may be a form of compartment pressure release, but the specific mechanism has not been revealed. Here, we mapped out the proteomic landscape of fracture blister fluid for the first time and compared its expression profile to cupping and burn blisters.

Methods

First, fluid samples were collected from 15 patients with fracture blisters, 7 patients with cupping blisters, and 9 patients with burn blisters. Then, the expression levels of 92 inflammatory proteins were measured using the Olink Target 96 Inflammation panel. Protein profiles were compared across the three groups using Differential Protein Expression Analysis and Principal Component Analysis (PCA).

Results

Fracture blisters had significantly higher levels of 50 proteins in comparison to cupping and 26 proteins in comparison to burn blisters. Notably, PCA showed fracture blisters closely resembled the protein expression profile of burn blisters but were distinct from the protein expression profile of cupping blisters.

Conclusion

Our study provides the first characterization of fracture blister fluid using proteomics, which provides a valuable reference for further analysis of the difference between blisters caused by fractures and those caused by other pathogenic factors. This compendium of proteomic data provides valuable insights and a rich resource to better understand fracture blisters.

miRNA-encapsulated abiotic materials and biovectors for cutaneous and oral wound healing: Biogenesis, mechanisms, and delivery nanocarriers

MicroRNAs (miRNAs) as therapeutic agents have attracted increasing interest in the past decade owing to their significant effectiveness in treating a wide array of ailments. These polymerases II-derived noncoding RNAs act through post-transcriptional controlling of different proteins and their allied pathways. Like other areas of medicine, researchers have utilized miRNAs for managing acute and chronic wounds. The increase in the number of patients suffering from either under-healing or over-healing wound demonstrates the limited efficacy of the current wound healing strategies and dictates the demands for simpler approaches with greater efficacy. Various miRNA can be designed to induce pathway beneficial for wound healing. However, the proper design of miRNA and its delivery system for wound healing applications are still challenging due to their limited stability and intracellular delivery. Therefore, new miRNAs are required to be identified and their delivery strategy needs to be optimized. In this review, we discuss the diverse roles of miRNAs in various stages of wound healing and provide an insight on the most recent findings in the nanotechnology and biomaterials field, which might offer opportunities for the development of new strategies for this chronic condition. We also highlight the advances in biomaterials and delivery systems, emphasizing their challenges and resolutions for miRNA-based wound healing. We further review various biovectors (e.g., adenovirus and lentivirus) and abiotic materials such as organic and inorganic nanomaterials, along with dendrimers and scaffolds, as the delivery systems for miRNA-based wound healing. Finally, challenges and opportunities for translation of miRNA-based strategies into clinical applications are discussed.

Progress in salivary glands: Endocrine glands with immune functions

The production and secretion of saliva is an essential function of the salivary glands. Saliva is a complicated liquid with different functions, including moistening, digestion, mineralization, lubrication, and mucosal protection. This review focuses on the mechanism and neural regulation of salivary secretion, and saliva is secreted in response to various stimuli, including odor, taste, vision, and mastication. The chemical and physical properties of saliva change dynamically during physiological and pathophysiological processes. Moreover, the central nervous system modulates salivary secretion and function via various neurotransmitters and neuroreceptors. Smell, vision, and taste have been investigated for the connection between salivation and brain function. The immune and endocrine functions of the salivary glands have been explored recently. Salivary glands play an essential role in innate and adaptive immunity and protection. Various immune cells such as B cells, T cells, macrophages, and dendritic cells, as well as immunoglobins like IgA and IgG have been found in salivary glands. Evidence supports the synthesis of corticosterone, testosterone, and melatonin in salivary glands. Saliva contains many potential biomarkers derived from epithelial cells, gingival crevicular fluid, and serum. High level of matrix metalloproteinases and cytokines are potential markers for oral carcinoma, infectious disease in the oral cavity, and systemic disease. Further research is required to monitor and predict potential salivary biomarkers for health and disease in clinical practice and precision medicine.

Histatin-1 alleviates high-glucose injury to skin keratinocytes through MAPK signaling pathway

BACKGROUND

Damage to keratinocytes and other skin cells in a high-glucose environment has been proven to be an important reason for the poor wound healing ability of chronic diabetes mellitus. Histatin-1 has been preliminarily proven to stimulate the wound healing process of the oral and non-oral mucosa and has been found to be related to the activation of extracellular signal-regulated kinase (ERK).

AIM OF THE STUDY

The purpose of this study was to investigate the effect of histatin-1 on high-glucose-injured keratinocytes and the role of the Ras-Raf-MEK-ERK signaling pathway on the effect of histatin-1 to improve diabetic wound healing.

METHODS

A human keratinocyte model damaged by high glucose was constructed, cell proliferation was detected by the Cell Counting Kit-8 assay, and cell apoptosis was detected by flow cytometry. The expression level of 8-hydroxy-2'-deoxyguanosine (8-OHdG) was detected by ELISA, and the mitogen-activated protein kinase (MAPK) signaling pathway protein expression level was detected by Western blot. C-fos mRNA expression was detected by real-time PCR.

RESULTS

The results indicated that histatin-1 promoted proliferation and reduced the rate of apoptosis and 8-OHdG content in keratinocytes with high-glucose injury. In addition, histatin-1 down-regulated MEK phosphorylation in keratinocytes with high-glucose injury. However, with the extension of the intervention, the effect of histatin-1 on c-fos mRNA expression was different. At the early stage of high-glucose injury (12 h), the expression of c-fos mRNA was not increased in high-glucose-injured keratinocytes treated with histatin-1 but then c-fos mRNA expression was gradually upregulated.

CONCLUSION

Histatin-1 could alleviate keratinocyte injury caused by high glucose levels and promoted wound healing in vitro. In addition, histatin-1 could exert anti-apoptotic and antioxidant damage effects under high-glucose injury states. These effects of histatin-1 may be related to its regulation of the MAPK signaling pathway. Therefore, these findings provide an essential theoretical basis for histatin-1 to become a safe and effective new peptide biological agent to promote wound healing in patients with diabetes.

From Chronic Wounds to Scarring: The Growing Health Care Burden of Under- and Over-Healing Wounds

Significance: Wound healing is the largest medical market without an existing small molecule/drug treatment. Both "under-healing" (chronic wounds) and "over-healing" (scarring) cause a substantial biomedical burden and lifelong consequences for patients. These problems cost tens of billions of dollars per year in the United States alone, a number expected to grow as the population ages and the prevalence of common comorbidities (e.g., diabetes) rises. However, no therapies currently exist to produce the "ideal" healing outcome: efficient wound repair through regeneration of normal tissue. Recent Advances: Ongoing research continues to illuminate possible therapeutic avenues for wound healing. By identifying underlying mechanisms of wound repair-for instance, tissue mechanics' role in fibrosis or cell populations that modulate wound healing and scarring-novel molecular targets may be defined. This Advances in Wound Care Forum issue includes reviews of scientific literature and original research from the Hagey Laboratory for Pediatric Regenerative Medicine at Stanford and its alumni, including developing approaches for encouraging wound healing, minimizing fibrosis, and coaxing regeneration. Critical Issues: Wound healing problems reflect an enormous and rapidly expanding clinical burden. The issues of both under- and over-healing wound outcomes will continue to expand as their underlying causes (e.g., diabetes) grow. Targeted treatments are needed to enable wound repair with functional tissue restoration and decreased scarring. Future Directions: Basic scientists will continue to refine understanding of factors driving undesirable wound outcomes. These discoveries are beginning to be translated and, in the coming years, will hopefully form the foundation for antiscarring drugs and other wound therapeutics.

Oral mucosa equivalents, prevascularization approaches, and potential applications

BACKGROUND

Oral mucosa equivalents (OMEs) have been used as in vitro models (eg, for studies of human oral mucosa biology and pathology, toxicological and pharmacological tests of oral care products), and clinically to treat oral defects. However, the human oral mucosa is a highly vascularized tissue and implantation of large OMEs can fail due to a lack of vascularization. To develop equivalents that better resemble the human oral mucosa and increase the success of implantation to repair large-sized defects, efforts have been made to prevascularize these constructs.

PURPOSE

The aim of this narrative review is to provide an overview of the human oral mucosa structure, common approaches for its reconstruction, and the development of OMEs, their prevascularization, and in vitro and clinical potential applications.

STUDY SELECTION

Articles on non-prevascularized and prevascularized OMEs were included, since the development and applications of non-prevascularized OMEs are a foundation for the design, fabrication, and optimization of prevascularized OMEs.

CONCLUSIONS

Several studies have reported the development and in vitro and clinical applications of OMEs and only a few were found on prevascularized OMEs using different approaches of fabrication and incorporation of endothelial cells, indicating a lack of standardized protocols to obtain these equivalents. However, these studies have shown the feasibility of prevascularizing OMEs and their implantation in animal models resulted in enhanced integration and healing. Vascularization in tissue equivalents is still a challenge, and optimization of cell culture conditions, biomaterials, and fabrication techniques along with clinical studies is required.

A Systematic Review of Keratinocyte Secretions: A Regenerative Perspective

Cell regenerative therapy is a modern solution for difficult-to-heal wounds. Keratinocytes, the most common cell type in the skin, are difficult to obtain without the creation of another wound. Stem cell differentiation towards keratinocytes is a challenging process, and it is difficult to reproduce in chemically defined media. Nevertheless, a co-culture of keratinocytes with stem cells usually achieves efficient differentiation. This systematic review aims to identify the secretions of normal human keratinocytes reported in the literature and correlate them with the differentiation process. An online search revealed 338 references, of which 100 met the selection criteria. A total of 80 different keratinocyte secretions were reported, which can be grouped mainly into cytokines, growth factors, and antimicrobial peptides. The growth-factor group mostly affects stem cell differentiation into keratinocytes, especially epidermal growth factor and members of the transforming growth factor family. Nevertheless, the reported secretions reflected the nature of the involved studies, as most of them focused on keratinocyte interaction with inflammation. This review highlights the secretory function of keratinocytes, as well as the need for intense investigation to characterize these secretions and evaluate their regenerative capacities.

Acellular dermal matrix decorated with collagen-affinity peptide accelerate diabetic wound healing through sustained releasing Histatin-1 mediated promotion of angiogenesis

Treating diabetic ulcers is a major challenge in clinical practice, persecuting millions of patients with diabetes and increasing the medical burden. Recombinant growth factor application can accelerate diabetic wound healing via angiogenesis. The local administration of recombinant growth factors has no robust clinical efficiency because of the degradation of append short duration of the molecules in the hostile inflammatoryenvironment.The present study focused on the pathophysiology of impaired neovascularization and growth factor short duration in the diabetic wound. We prepared a collagen-binding domain (CBD)-fused recombinant peptide (C-Histatin-1) that had both pro-angiogenesis capacity and collagen-affinity properties. Next, we created a biocompatible acellular dermal matrix (ADM) as a drug delivery carrier that featured collagen-richness, high porosity, and non-cytotoxicity. C-Histatin-1 was then tethered on ADM to obtain a sustained-release effect. Finally, a functional scaffold (C-Hst1/ADM) was developed. C-Hst1/ADM can sustain-release Histatin-1 to promote the adhesion, migration, and angiogenesisof vascular endothelial cells in vitro. Using a diabetic wound model, we showed that C-Hst1/ADM could significantly promote angiogenesis, reduce scar widths, and improve extracellular collagen accumulation. Therefore, the results of this study provide a foundation for the clinical application of C-Hst1/ADM covering scaffold in the treatment of diabetic wounds.

Cobalt protoporphyrin promotes human keratinocyte migration under hyperglycemic conditions

Background

Complete healing of diabetic wounds continues to be a clinically unmet need. Although robust therapies such as stem cell therapy and growth factor treatment are clinically applied, these treatments are costly for most diabetic wound patients. Therefore, a cheaper alternative is needed. Cobalt protoporphyrin (CoPP) has recently been demonstrated to promote tissue regeneration. In this study, the therapeutic benefits of CoPP in diabetic wound healing were examined.

Methods

An in vitro wound healing model that mimics re-epithelialization was established to examine the effect of CoPP on the migratory capability of human keratinocytes (HaCaT) in either normal glucose (NG) or high glucose (HG) media, as well as in the presence of either H₂O₂ or lipopolysaccharide (LPS). At the end of the migration assays, cells were collected and subjected to Western blotting analysis and immunostaining.

Results

HaCaT were found to migrate significantly more slowly in the HG media compared to the NG media. CoPP treatment was found to enhance cell migration in HG media, but was found to decrease cell migration and proliferation when HaCaT were cultured in NG media. CoPP treatment induced high levels of expression of Nrf-2/HO-1 and FoxO1 in HaCaT cultured in either glucose concentration, although the FoxO1 expression was found to be significantly higher in HaCaT that underwent the migration assay in NG media compared to those in HG media. The higher level of FoxO1 expression seen in CoPP-treated HaCaT cultured in NG media resulted in upregulation of CCL20 and downregulation of TGFβ1. In contrast, HaCaT migrated in HG media were found to have high levels of expression of TGFβ1, and low levels of expression of CCL20. Interestingly, in the presence of H₂O₂, CoPP-pretreated HaCaT cultured in either NG or HG media had similar expression level of Nrf-2/HO-1 and FoxO1 to each other. Moreover, the anti-apoptotic effect of CoPP pretreatment was noticed in HaCaT cultured in either glucose concentration. Additionally, CoPP pretreatment was shown to promote tight junction formation in HaCaT suffering from LPS-induced damage.

Conclusions

CoPP enhances cell migratory capacity under hyperglycemic conditions, and protects cells from oxidative and LPS-induced cellular damage in HG media containing either H₂O₂ or LPS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-022-00499-0.

Amino Acid-Enriched Formula for the Post-Operative Care of Extraction Sockets Evaluated by 3-D Intraoral Scanning

Background: Hyaluronic acid and amino acids play an important role in the wound healing process, stimulating the development of the connective tissue and the activity and proliferation of fibroblasts. The aim of the present controlled clinical study was to evaluate the clinical efficacy of a topical gel formula containing hyaluronic acid and amino acids in terms of wound closure rate, painkiller intake, and patients’ reported pain and edema. Methods: This study included patients in need of a single tooth extraction. Patients were randomized into two groups with differing post-operative care regimens. Patients in the test group used the amino acid and hyaluronic acid-based gel, while the control group did not use any product. Each parameter was measured in both groups at different time points: immediately after surgery, and after 7, 14, 30, and 60 days. Results: A total of 40 patients (46.52 ± 9.84 years old) completed the observational period, and 40 extraction sockets were examined. After 7 days, the edema was significantly lower in the test group. The reported pain was lower in the test group without a significant difference, except for the first time point at 7 days. With the follow-up questionnaire, patients declared to have taken painkillers mainly during the first 7 days after surgery; however, the test group showed a lower need for painkillers than the control group. Conclusion: The post-operative and domiciliary use of an amino acid and hyaluronic acid-based gel for the management of soft tissue closure after tooth extraction is a valid coadjutant to reduce swelling, pain, and the need for painkillers. Additional studies are required to support the results of the present study.

Platelet-Released Growth Factors Influence Wound Healing-Associated Genes in Human Keratinocytes and Ex Vivo Skin Explants

Platelet-released growth factors (PRGFs) or other thrombocyte concentrate products, e.g., Platelet-Rich Fibrin (PRF), have become efficient tools of regenerative medicine in many medical disciplines. In the context of wound healing, it has been demonstrated that treatment of chronic or complicated wounds with PRGF or PRF improves wound healing in the majority of treated patients. Nevertheless, the underlying cellular and molecular mechanism are still poorly understood. Therefore, we aimed to analyze if PRGF-treatment of human keratinocytes caused the induction of genes encoding paracrine factors associated with successful wound healing. The investigated genes were Semaphorin 7A (SEMA7A), Angiopoietin-like 4 (ANGPLT4), Fibroblast Growth Factor-2 (FGF-2), Interleukin-32 (IL-32), the CC-chemokine-ligand 20 (CCL20), the matrix-metalloproteinase-2 (MMP-2), the chemokine C-X-C motif chemokine ligand 10 (CXCL10) and the subunit B of the Platelet-Derived Growth Factor (PDGFB). We observed a significant gene induction of SEMA7A, ANGPLT4, FGF-2, IL-32, MMP-2 and PDGFB in human keratinocytes after PRGF treatment. The CCL20- and CXCL10 gene expressions were significantly inhibited by PRGF therapy. Signal transduction analyses revealed that the PRGF-mediated gene induction of SEMA7A, ANGPLT4, IL-32 and MMP-2 in human keratinocytes was transduced via the IL-6 receptor pathway. In contrast, EGF receptor signaling was not involved in the PRGF-mediated gene expression of analyzed genes in human keratinocytes. Additionally, treatment of ex vivo skin explants with PRGF confirmed a significant gene induction of SEMA7A, ANGPLT4, MMP-2 and PDGFB. Taken together, these results describe a new mechanism that could be responsible for the beneficial wound healing properties of PRGF or related thrombocytes concentrate products such as PRF.

Relics and Historical Uses of Human Zootherapeutic Products in Contemporary Spanish Ethnoveterinary Medicine

(1) Background: this review documents the wide repertoire of practices and remedies based on the use of human-derived products in Spanish ethnoveterinary medicine (EVM) from the early 20th century to the present. These practices are compared with historical data and those of other countries; (2) Methods: a search using advanced functions in the most important databases in the fields of ethnobiology, EVM, folklore, and ethnography was performed. Information was obtained from 29 documentary sources; (3) Results: from the search of the literature, 46 use-reports related to the veterinary use of human urine, menstrual fluid, saliva, breast milk, and faeces were recorded. These zootherapeutic resources are/were used to treat 20 animal diseases, in particular dermatological ailments. In addition, many practices of the magical-religious type are documented; (4) Conclusions: the veterinary uses described and analysed here are fundamental to the development of therapeutic tools and creating teaching and learning processes in new popular veterinary practices adapted to the users and those who demand them. The information collected could form a scientific foundation for future inventories of local veterinary knowledge (LVK) and research addressing the discovery of new drugs for livestock. This work contributes to the inventory of some uses, traditional practices, and rituals seriously threatened by the progressive loss of LVK in Europe.

Nutrition and cutaneous wound healing

Wound healing is a complex and energy-demanding process. The relationship between nutrition and wound healing has been recognized for many centuries. Several studies have indicated that nutritional deficiencies are more prevalent among patients with chronic wounds. Malnutrition may alter the inflammatory response, collagen synthesis, and wound tensile strength, all of which are crucial for wound healing. Although the specific role of nutrition and supplementation in wound care remains uncertain, it is necessary to identify and correct nutritional imbalances to avoid any potential deterioration of the healing process. It is also important to recognize the differences in pathophysiology between acute and chronic wounds. A burn, surgical, or a traumatic wound is different from a diabetic foot ulcer, which is different from a pressure ulcer. Chronic wounds are more prevalent in the aging population, and patients often have underlying comorbidities, such as diabetes mellitus, peripheral vascular disease, connective tissue disease, or other systemic illnesses that may alter energy metabolism and contribute to impaired healing. Management approaches to acute wound care may not apply universally to chronic wounds. In this review, we discuss the available data and possible roles for nutrition in wound healing.

The Bigger Picture: Why Oral Mucosa Heals Better Than Skin

Wound healing is an essential process to restore tissue integrity after trauma. Large skin wounds such as burns often heal with hypertrophic scarring and contractures, resulting in disfigurements and reduced joint mobility. Such adverse healing outcomes are less common in the oral mucosa, which generally heals faster compared to skin. Several studies have identified differences between oral and skin wound healing. Most of these studies however focus only on a single stage of wound healing or a single cell type. The aim of this review is to provide an extensive overview of wound healing in skin versus oral mucosa during all stages of wound healing and including all cell types and molecules involved in the process and also taking into account environmental specific factors such as exposure to saliva and the microbiome. Next to intrinsic properties of resident cells and differential expression of cytokines and growth factors, multiple external factors have been identified that contribute to oral wound healing. It can be concluded that faster wound closure, the presence of saliva, a more rapid immune response, and increased extracellular matrix remodeling all contribute to the superior wound healing and reduced scar formation in oral mucosa, compared to skin.

A Scarless Healing Tale: Comparing Homeostasis and Wound Healing of Oral Mucosa With Skin and Oesophagus

Epithelial tissues are the most rapidly dividing tissues in the body, holding a natural ability for renewal and regeneration. This ability is crucial for survival as epithelia are essential to provide the ultimate barrier against the external environment, protecting the underlying tissues. Tissue stem and progenitor cells are responsible for self-renewal and repair during homeostasis and following injury. Upon wounding, epithelial tissues undergo different phases of haemostasis, inflammation, proliferation and remodelling, often resulting in fibrosis and scarring. In this review, we explore the phenotypic differences between the skin, the oesophagus and the oral mucosa. We discuss the plasticity of these epithelial stem cells and contribution of different fibroblast subpopulations for tissue regeneration and wound healing. While these epithelial tissues share global mechanisms of stem cell behaviour for tissue renewal and regeneration, the oral mucosa is known for its outstanding healing potential with minimal scarring. We aim to provide an updated review of recent studies that combined cell therapy with bioengineering exporting the unique scarless properties of the oral mucosa to improve skin and oesophageal wound healing and to reduce fibrotic tissue formation. These advances open new avenues toward the ultimate goal of achieving scarless wound healing.

Patch test of dental materials in Oral Lichen Planus with considering the role of saliva

Lichen planus is the most common skin disease that affects the oral mucosa. Oral Lichen Planus is a T-cell-mediated autoimmune disorder. In the current study, for the first time, an oral cavity condition in skin patch tests with adding saliva is simulated. In addition, the patch results are compared with healthy subjects. Forty-one OLP patients and 63 healthy subjects were enrolled in the study. All participants were provided with patch tests, including allergens, in combination with saliva in chambers. Allergens from the European baseline (standard) series selected according to the most prevalent positive results in the previous study were applied. Positive results of Mercury and Cobalt tests were significantly higher in the case group. In this study, the differentiation of patients with lichen planus and lichenoid was identified according to the Van der Meij & Van der Waal criteria. The patch test was conducted for healthy individuals as well. The most important of all was the use of patients' saliva in the patch test, done for the first time in this field. In the case of OLP, a patch test can help identify positive reactions to dental materials; thus, the replacement of dental restorations may be needed.

MicroRNA-31 Can Positively Regulate the Proliferation, Differentiation and Migration of Keratinocytes

In the past decades, the key roles of most microRNA in dermatosis and skin development have been explored one after another. Among them, microRNA-31 (miR-31) has a prominent role in the regulation of keratinocytes. Numerous studies show that miR-31 can positively regulate the proliferation, differentiation and cell activity of keratinocytes via regulating the NF-κB, RAS/MAPK, Notch signaling pathways, and some cytokines. At present, the interaction between miR-31 and the NF-κB signaling pathway in keratinocytes is a hot research topic. The positive feedback loop formed by miR-31 and NF-κB signaling may bring new ideas for the prevention of psoriasis. The abnormal state of keratinocytes is usually the pathological basis of many skin and immune system diseases. Therefore, strengthening the ability to regulate keratinocytes may be a breakthrough for a variety of diseases. At the same time, miR-31's capacity to accelerate wound healing via positively regulating keratinocytes should be further investigated in the treatment of chronic ulcers and trauma.

Long-Term Assessment of the In Vitro Corrosion Resistance of Biomimetic ACP Coatings Electrodeposited from an Acetate Bath

Calcium phosphate coatings are able to improve the osseointegration process due to their chemical composition, which is similar to that of bone tissues. In this work, to increase the long-term corrosion resistance and to improve the osseointegration process of commercially pure titanium Grade 4 (CpTi G4), biomimetic amorphous calcium phosphate (ACP) coatings were electrodeposited for the first time from an acetate bath with a pH level of 7.0 and a Ca:P ratio of 1.67. ACP coatings were obtained on CpTi G4 substrate subjected to sandblasting and autoclaving using electrochemically assisted deposition at a potential of -3 V relative to the open circuit potential for 30 min at room temperature. SEM, EDS, 2D roughness profiles, amplitude-sensitive eddy current method, and Kelvin scanning probe were used for the surface characterization of the biomaterial under study. In vitro corrosion resistance tests were conducted for 21 days in artificial saliva using open circuit potential, polarization curves, and electrochemical impedance spectroscopy measurements. The passive-transpassive behavior was revealed for the obtained ACP coatings. The long-term corrosion resistance test showed a deterioration of the protective properties for CpTi G4 uncoated and coated with ACP with immersion time. The mechanism and kinetics of the pitting corrosion on the CpTi G4|TiO2|ACP coating system are discussed in detail.

Effect of green propolis extracts on experimental aged gingival irritation in vivo and in vitro

OBJECTIVES

Tooth bleaching has become one of the most frequently requested esthetic procedures in dental practice. A side effect of bleaching is gingival irritation. This study examined the efficacy of propolis to treat gingival irritation caused by bleaching in vivo and in vitro.

METHODS

Gingival irritation was mimicked by a mild burn injury to oral mucosa in young (10 week old) and aged (18 month old) mice. Propolis ointment was immediately applied to the burn area. After 24 h, gingiva was collected to determine the efficacy of propolis by hematoxylin and eosin staining and real-time polymerase chain reaction (PCR).

RESULTS

Topical application of propolis ointment reduced the infiltration of inflammatory cells at irritated sites and promoted the repair of the mucosal epithelium in young and aged mice. It also suppressed the expression of IL-1β and TNF-α and increased keratin 1 and 5 expression in the irritated gingiva. Propolis suppressed an increase in IL-1β and TNF-α upon stimulation with H₂O₂ in young and SA-β-gal-expressing senescent human gingival fibroblasts (HGFs) cultures.

CONCLUSIONS

Propolis may be effective for mucosal repair in gingival irritation as it suppresses the expression of proinflammatory cytokines and promotes keratin expression.

Effects and mechanisms of histatins as novel skin wound-healing agents

Wound healing is a complex and important physiological process that maintains the integrity of skin after various injuries. Abnormal wound healing, especially of chronic wounds, impairs normal physical function. Therefore, the search for effective and safe healing agents is one of the main concerns. Histatins are histidine-rich low molecular weight peptides that are expressed in the saliva of both humans and higher primates. Histatins have two main biological effects, cell stimulation and bacteria killing, with the former playing an important role in wound healing by promoting epithelial cell and fibroblast migration and angiogenesis and enhancing the re-epithelialization of the wounded area. Because of these biological effects, histatins have been shown to be promising agents of improved wound healing. Histatins are categorized into many subtypes, of which histatin 1 and its hydrolysates are the most effective in promoting wound healing. This review addresses the bioactivity of histatins in wound healing, such as their stimulatory effects on epithelial cells and fibroblasts, and elucidates the possible mechanisms by which histatin subtypes induce their biological effects.

Transcriptomic and Morphological Analysis of Cells Derived from Porcine Buccal Mucosa-Studies on an In Vitro Model

Simple Summary

Domestic pigs express high phylogenetic similarity to humans and are often used as a compatible model in biomedical research. Porcine tissues are used as an accessible biomaterial in human skin transplants and tissue architecture reconstruction. We used transcriptional analysis to investigate the dynamics of complex biological system of the mucosa. Additionally, we performed computer analysis of microscopic images of cultured cells in vitro. Computer analysis of images identified epithelial cells and connective tissue cells in in vitro culture.

Abstract

Transcriptional analysis and live-cell imaging are a powerful tool to investigate the dynamics of complex biological systems. In vitro expanded porcine oral mucosal cells, consisting of populations of epithelial and connective lineages, are interesting and complex systems for study via microarray transcriptomic assays to analyze gene expression profile. The transcriptomic analysis included 56 ontological groups with particular focus on 7 gene ontology groups that are related to the processes of differentiation and development. Most analyzed genes were upregulated after 7 days and downregulated after 15 and 30 days of in vitro culture. The performed transcriptomic analysis was then extended to include automated analysis of differential interference contrast microscopy (DIC) images obtained during in vitro culture. The analysis of DIC imaging allowed to identify the different populations of keratinocytes and fibroblasts during seven days of in vitro culture, and it was possible to evaluate the proportion of these two populations of cells. Porcine mucosa may be a suitable model for reference research on human tissues. In addition, it can provide a reference point for research on the use of cells, scaffolds, or tissues derived from transgenic animals for applications in human tissues reconstruction.

Differential influence of Streptococcus mitis on host response to metals in reconstructed human skin and oral mucosa

BACKGROUND

Skin and oral mucosa are continuously exposed to potential metal sensitizers while hosting abundant microbes, which may influence the host response to sensitizers. This host response may also be influenced by the route of exposure that is skin or oral mucosa, due to their different immune properties.

OBJECTIVE

Determine how commensal Streptococcus mitis influences the host response to nickel sulfate (sensitizer) and titanium(IV) bis(ammonium lactato)dihydroxide (questionable sensitizer) in reconstructed human skin (RHS) and gingiva (RHG).

METHODS

RHS/RHG was exposed to nickel or titanium, in the presence or absence of S. mitis for 24 hours. Histology, cytokine secretion, and Toll-like receptors (TLRs) expression were assessed.

RESULTS

S. mitis increased interleukin (IL)-6, CXCL8, CCL2, CCL5, and CCL20 secretion in RHS but not in RHG; co-application with nickel further increased cytokine secretion. In contrast, titanium suppressed S. mitis-induced cytokine secretion in RHS and had no influence on RHG. S. mitis and metals differentially regulated TLR1 and TLR4 in RHS, and predominantly TLR4 in RHG.

CONCLUSION

Co-exposure of S. mitis and nickel resulted in a more potent innate immune response in RHS than in RHG, whereas titanium remained inert. These results indicate the important influence of commensal microbes and the route of exposure on the host's response to metals.

Carbonic Anhydrase VI in Skin Wound Healing Study on Car6 Knockout Mice

Carbonic anhydrases (CAs) contribute to tumor cell migration by generating an acidic environment through the conversion of carbon dioxide to bicarbonate and a proton. CA VI is secreted to milk and saliva, and it could contribute to wound closure, as a potential trophic factor, in animals that typically lick their wounds. Our aim was to investigate whether human CA VI improves skin-wound healing in full-thickness skin-wound models. The effect was studied in Car6 ^-/- knockout mice and wild type littermates. Half of both mice strains were given topically administered, milk-derived CA VI after wounding and eight hours later. The amount of topically given CA VI exceeded the predicted amount of natural saliva-delivered CA VI. The healing was followed for seven days and studied from photographs and histological sections. Our results showed no significant differences between the treatment groups in wound closure, re-epithelization, or granulation tissue formation, nor did the Car6 genotype affect the healing. Our results demonstrate that CA VI does not play a major role in skin-wound healing and also suggest that saliva-derived CA VI is not responsible for the licking-associated improved wound healing in animals.

Human serum proteins bind to Sporothrix schenckii conidia with differential effects on phagocytosis

Serum is an important source of proteins that interact with pathogens. Once bound to the cell surface, serum proteins can stimulate the innate immune system. The phagocytosis of Sporothrix schenckii conidia by human macrophages is activated through human serum opsonisation. In this study, we have attempted to characterise human blood serum proteins that bind to the cell wall of S. schenckii conidia. We systematically observed the same four proteins independent of the plasma donor: albumin, serum amyloid protein (SAP), α-1 antitrypsin (AAT), and transferrin were identified with the help of tandem mass spectrometry. Phagocytosis depended on the concentration of the SAP or α-1 antitrypsin that was used to opsonise the conidia; however, transferrin or albumin did not have any effect on conidia internalisation. The presence of mannose did not affect macrophage phagocytosis of the conidia opsonised with SAP or α-1 antitrypsin, which suggests that these proteins are not recognised by the mannose receptor.

Effectiveness of Low-Level Laser Therapy with a 915 Nm Wavelength Diode Laser on the Healing of Intraoral Mucosal Wound: An Animal Study and a Double-Blind Randomized Clinical Trial

Background and objectives: Diode laser has been the most popular low-level laser therapy (LLLT) technique in dentistry due to its good tissue penetration, lower financial costs, small size for portable application, and convenience to use. A series of recent studies with 940 nm or 980 nm lasers demonstrated that LLLT showed positive effects after third molar extraction or periodontal flap surgery. However, the effects of LLLT on intraoral mucosal wound healing after surgical incision have not yet been determined in human clinical study. Materials and Methods: The present study was performed to determine the efficacy and safety of 915 nm wavelength low-level laser therapy (LLLT) in mucosal wound healing. A total of 108 Sprague-Dawley rats were used. They were divided into three groups: Abrasive wound group, immediate LLLT once group, and daily LLLT group. As a clinical study, a total of 16 patients with split-mouth design subjected to bilateral mandibular third molar extraction were allocated into the LLLT group and placebo group. The process of LLLT was performed on postoperative days 0, 1, and 7, and parameters related to wound healing were analyzed on days 1, 7, and 14. Results: Repeated laser irradiation promoted mucosal wound healing of the rats. In the clinical study, although there were no significant statistical differences between the LLLT and placebo groups in all inflammatory parameters, the early stage mucosal healing tendency of wound dehiscence was higher in the LLLT group than in the placebo group clinically on postoperative day 1. Conclusions: The present results showed that 915 nm LLLT could be applied safely as an auxiliary therapy for mucosal wound healing.

Human saliva stimulates skin and oral wound healing in vitro

Despite continuous exposure to environmental pathogens, injured mucosa within the oral cavity heals faster and almost scar free compared with skin. Saliva is thought to be one of the main contributing factors. Saliva may possibly also stimulate skin wound healing. If so, it would provide a novel therapy for treating skin wounds, for example, burns. This study aims to investigate the therapeutic wound healing potential of human saliva in vitro. Human saliva from healthy volunteers was filter sterilized before use. Two different in vitro wound models were investigated: (a) open wounds represented by 2D skin and gingiva cultures were used to assess fibroblast and keratinocyte migration and proliferation and (b) blister wounds represented by introducing freeze blisters into organotypic reconstructed human skin and gingiva. Re‐epithelialization and differentiation (keratin K10, K13, K17 expression) under the blister and inflammatory wound healing mediator secretion was assessed. Saliva‐stimulated migration of skin and oral mucosa fibroblasts and keratinocytes, but only fibroblast proliferation. Topical saliva application to the blister wound on reconstructed skin did not stimulate re‐epithelization because the blister wound contained a dense impenetrable dead epidermal layer. Saliva did promote an innate inflammatory response (increased CCL20, IL‐6, and CXCL‐8 secretion) when applied topically to the flanking viable areas of both wounded reconstructed human skin and oral mucosa without altering the skin specific keratin differentiation profile. Our results show that human saliva can stimulate oral and skin wound closure and an inflammatory response. Saliva is therefore a potential novel therapeutic for treating open skin wounds.