Cellular, Biochemical, and Clinical Aspects of Wound Healing

Preparing Patients for Cosmetic Surgery and Aesthetic Procedures: Ensuring an Optimal Nutritional Status for Successful Results

Aesthetic and cosmetic medical practices have attracted considerable consumer attention globally. However, possible complications vary and range from mild, self-resolving ecchymoses or edema to more persistent complications. The aim of this review is to identify the nutritional deficits or excesses associated with the major complications of reconstructive surgery, aesthetic surgery, and mini-invasive aesthetic procedures. An additional goal is to provide a bundle of actions for professionals working in the industry in order to reduce the risks of aesthetic procedures and improve the clinical outcomes. Granulomas, hypertrophic scars and keloids, seromas, infections and xerosis, hyperpigmentation, petechiae, livedo reticularis, slower wound healing, and other poor outcomes are frequently associated with nutritional deficiencies. Nutritional status can markedly affect wound healing and tissue repair following surgical interventions, as well as the outcomes of aesthetic and cosmetic medical practices. Professionals working in this industry, therefore, need to consider the nutritional aspects of their patients to obtain the best results.

Proteomics as a tool to improve novel insights into skin diseases: what we know and where we should be going

Background

Biochemical processes involved in complex skin diseases (skin cancers, psoriasis, and wound) can be identified by combining proteomics analysis and bioinformatics tools, which gain a next-level insight into their pathogenesis, diagnosis, and therapeutic targets.

Methods

Articles were identified through a search of PubMed, Embase, and MEDLINE references dated to May 2022, to perform system data mining, and a search of the Web of Science (WoS) Core Collection was utilized to conduct a visual bibliometric analysis.

Results

An increased trend line revealed that the number of publications related to proteomics utilized in skin diseases has sharply increased recent years, reaching a peak in 2021. The hottest fields focused on are skin cancer (melanoma), inflammation skin disorder (psoriasis), and skin wounds. After deduplication and title, abstract, and full-text screening, a total of 486 of the 7,822 outcomes met the inclusion/exclusion criteria for detailed data mining in the field of skin disease tooling with proteomics, with regard to skin cancer. According to the data, cell death, metabolism, skeleton, immune, and inflammation enrichment pathways are likely the major part and hotspots of proteomic analysis found in skin diseases. Also, the focuses of proteomics in skin disease are from superficial presumption to depth mechanism exploration within more comprehensive validation, from basic study to a combination or guideline for clinical applications. Furthermore, we chose skin cancer as a typical example, compared with other skin disorders. In addition to finding key pathogenic proteins and differences between diseases, proteomic analysis is also used for therapeutic evaluation or can further obtain in-depth mechanisms in the field of skin diseases.

Conclusion

Proteomics has been regarded as an irreplaceable technology in the study of pathophysiological mechanism and/or therapeutic targets of skin diseases, which could provide candidate key proteins for the insight into the biological information after gene transcription. However, depth pathogenesis and potential clinical applications need further studies with stronger evidence within a wider range of skin diseases.

Spontaneous Bone Healing after Cysts Enucleation without Bone Grafting Materials: A Randomized Clinical Study

The aim of this study was to evaluate spontaneous bone regeneration after cysts enucleation of the jaws without the use of bone grafting materials. We included 18 patients at random (11 men and 7 women) with a mean age of 31.8 years, with jaw cysts treated by enucleation, without the use of grafting materials. A method of measurements to assess the percentage of reduction of the bone cavities was used to objectify the results. The patients were evaluated before and at least 6 months after surgery, with radiographic scans based on linear measures with a computerized method using Nemoceph program (Nemotec, NemoCeph Software, Madrid, España). The analysis of the sample shows an average of 85.59% decrease in horizontal measures, 89.53% in the vertical, and 88.98 and 89.81% in the diagonal left and right, respectively. The total average reduction was 88.47%. It showed a greater decrease in vertical and diagonal measurements with respect to horizontal. Regeneration in 12 patients was 100% and in 6 patients was higher at 50.4%. Bone density increased in the postoperative radiographs. The results suggest that in some cases, spontaneous bone regeneration can be achieved by cysts enucleation without bone grafting materials.

Chitosan-based copper nanocomposite accelerates healing in excision wound model in rats

Copper possesses efficacy in wound healing which is a complex phenomenon involving various cells, cytokines and growth factors. Copper nanoparticles modulate cells, cytokines and growth factors involved in wound healing in a better way than copper ions. Chitosan has been shown to be beneficial in healing because of its antibacterial, antifungal, biocompatible and biodegradable polymeric nature. In the present study, chitosan-based copper nanocomposite (CCNC) was prepared by mixing chitosan and copper nanoparticles. CCNC was applied topically to evaluate its wound healing potential and to study its effects on some important components of healing process in open excision wound model in adult Wistar rats. Significant increase in wound contraction was observed in the CCNC-treated rats. The up-regulation of vascular endothelial growth factor (VEGF) and transforming growth factor-beta1(TGF-β1) by CCNC-treatment revealed its role in facilitating angiogenesis, fibroblast proliferation and collagen deposition. The tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10) were significantly decreased and increased, respectively, in CCNC-treated rats. Histological evaluation showed more fibroblast proliferation, collagen deposition and intact re-epithelialization in CCNC-treated rats. Immunohistochemistry of CD31 revealed marked increase in angiogenesis. Thus, we concluded that chitosan-based copper nanocomposite efficiently enhanced cutaneous wound healing by modulation of various cells, cytokines and growth factors during different phases of healing process.

Proteome analysis reveals antiangiogenic environments in chronic wounds of diabetes mellitus type 2 patients

In contrast to normal healing wounds, chronic wounds commonly show disturbances in proteins regulating wound healing processes, particularly those involved in cell proliferation and protein degradation. Multidimensional protein identification technology MS/MS was conducted to investigate and compare the protein composition of chronic diabetic foot exudates to exudates from split-skin donor sites of burn victims otherwise healthy. Spectral counting revealed 188 proteins differentially expressed (more than twofold and p-value <0.05) in chronic wounds. Most were involved in biological processes including inflammation, angiogenesis, and cell mortality. Increased expression of the inflammatory response stimulating S100 proteins, predominantly S100A8 and S100A9 (almost tenfold), was identified. Matrix metalloproteinases (MMPs) MMP1, MMP2, and MMP8 were identified to be elevated in chronic wounds with significant impact on collagen degradation and tissue destruction. Further, proteins with antiangiogenic properties were found at higher expression levels in chronic wounds. Reduced angiogenesis leads to drastic shortage in nutrition supply and causes increased cell death, demonstrated by Annexin A5 exclusively found in chronic wound exudates. However, excessive nucleic and cytosolic material infers cell death occurring not only by apoptosis but also by necrosis. In conclusion, mass spectrometric investigation of exudates from chronic wounds demonstrated dramatic impairment in wound repair with excessive inflammation, antiangiogenic environment, and accelerated cell death.

Effect of Fibrin Glue on Collagen Deposition after Autologous Fascia Grafting in Rabbit Vocal Folds

Objectives:

Fibrin glue (FG) is a reaction product of fibrinogen and thrombin that forms a fibrin clot responsible for tissue adhesion. However, FG and its components may interfere with wound healing by interacting with cytokines such as transforming growth factor–β (TGF-β). The objective of this study was to investigate the effect of FG on collagen deposition after fascia grafting in the vocal folds of rabbits.

Methods:

Eighteen rabbits underwent autologous fascia grafting in both vocal folds, and the left side was fixed with FG. Each animal was painlessly sacrificed after 7, 30, or 90 days. The larynx was removed, and the vocal folds were prepared for histomorphometric analysis by picrosirius red staining to evaluate collagen deposition around the graft.

Results:

There was a significant increase in collagen density around the grafts at 90 days in the vocal folds that were fixed with FG (p = 0.0102) compared with the control vocal folds.

Conclusions:

Application of FG altered collagen deposition around the fascia grafts, leading to significantly increased collagen density after 90 days. Differences found in the composition of the extracellular matrix in later stages of the healing process are a result of changes that occur in the beginning of this process. Therapeutic interventions, such as the use of FG and/or its components, performed in the early stages of wound healing may interfere with the complex interactions of fibroblasts, inflammatory cells, and cytokines (especially TGF-β), thereby modulating the healing process.

Ultrastructural localization of integrin subunits beta4 and alpha3 within the migrating epithelial tongue of in vivo human wounds

Subsequent to wounding, keratinocytes must quickly restore barrier function. In vitro wound models have served to elucidate mechanisms of epithelial closure and key roles for integrins alpha6beta4 and alpha3beta1. To extrapolate in vitro data to in vivo human tissues, we used ultrathin cryomicrotomy to simultaneously observe tissue ultrastructure and immunogold localization in unwounded skin and acute human cutaneous wounds. Localization of the beta4 integrin subunit in unwounded skin shows dominant hemidesmosomal association and minor basal keratinocyte lateral filopodic cell-cell expression. After wounding, beta4 dominantly localized to cytokeratin-rich regions (trailing edge hemidesmosomes) and minor association with lamellipodia (leading edge). beta4 colocalizes with alpha3 within filopodia juxtaposed to wound matrix, and increased concentrations of beta4 were found in cytoplasmic vesicles within basal keratinocytes of the migrating tongue. alpha3 integrin subunit dominantly localized to filopodia within basal keratinocyte lateral cell-cell interfaces in unwounded skin and both cell-cell and cell-matrix filopodic interactions in wounded skin. This study indicates that beta4 interacts with the extracellular environment through both stable and transient interactions and may be managed through a different endosomal trafficking pathway than alpha3. alpha3 integrin, despite its ability to respond to alternate ligands after wounding, does so through a single structure, the filopodia.

Novel insights into wound healing sequence of events

Effective wound healing leads to restoration of tissue integrity and occurs through a highly organized multistage process involving various cell types. Currently, methods for wound healing assessment lack a structured system for analysis of quantitative parameters. We have established a unique quantitative assessment strategy of wound healing stages based on histological criteria. Distinctive immunohistochemical parameters including re-epithelialization, epidermal differentiation, cell migration, proliferation, inflammatory response as well as dermal closure, matrix distribution, and skin remodelling were identified and followed during the timeline of wound healing progression. Assessment was based on various defined characteristics and each stage-specific parameter was independently quantified for complete wound closure. This analysis allowed a follow-up of wound healing dynamics and identified the contribution of critical and specific parameters to wound healing physiology and pathology. In this review we demonstrate our assessment strategy of crucial wound healing events and introduce a unique quantification system for each of the processes involved in wound repair. We believe that our unique method can be utilized as a diagnostic platform for standardizing assessment of wound healing progression as well as a screening tool for potential therapies.

A critical role for TLR4 in the pathogenesis of necrotizing enterocolitis by modulating intestinal injury and repair

Necrotizing enterocolitis (NEC) is the leading cause of death from gastrointestinal disease in preterm infants and is characterized by translocation of LPS across the inflamed intestine. We hypothesized that the LPS receptor (TLR4) plays a critical role in NEC development, and we sought to determine the mechanisms involved. We now demonstrate that NEC in mice and humans is associated with increased expression of TLR4 in the intestinal mucosa and that physiological stressors associated with NEC development, namely, exposure to LPS and hypoxia, sensitize the murine intestinal epithelium to LPS through up-regulation of TLR4. In support of a critical role for TLR4 in NEC development, TLR4-mutant C3H/HeJ mice were protected from the development of NEC compared with wild-type C3H/HeOUJ littermates. TLR4 activation in vitro led to increased enterocyte apoptosis and reduced enterocyte migration and proliferation, suggesting a role for TLR4 in intestinal repair. In support of this possibility, increased NEC severity in C3H/HeOUJ mice resulted from increased enterocyte apoptosis and reduced enterocyte restitution and proliferation after mucosal injury compared with mutant mice. TLR4 signaling also led to increased serine phosphorylation of intestinal focal adhesion kinase (FAK). Remarkably, TLR4 coimmunoprecipitated with FAK, and small interfering RNA-mediated FAK inhibition restored enterocyte migration after TLR4 activation, demonstrating that the FAK-TLR4 association regulates intestinal healing. These findings demonstrate a critical role for TLR4 in the development of NEC through effects on enterocyte injury and repair, identify a novel TLR4-FAK association in regulating enterocyte migration, and suggest TLR4/FAK as a therapeutic target in this disease.

Modulation of muscle regeneration, myogenesis, and adipogenesis by the Rho family guanine nucleotide exchange factor GEFT

Rho family guanine nucleotide exchange factors (GEFs) regulate diverse cellular processes including cytoskeletal reorganization, cell adhesion, and differentiation via activation of the Rho GTPases. However, no studies have yet implicated Rho-GEFs as molecular regulators of the mesenchymal cell fate decisions which occur during development and repair of tissue damage. In this study, we demonstrate that the steady-state protein level of the Rho-specific GEF GEFT is modulated during skeletal muscle regeneration and that gene transfer of GEFT into cardiotoxin-injured mouse tibialis anterior muscle exerts a powerful promotion of skeletal muscle regeneration in vivo. In order to molecularly characterize this regenerative effect, we extrapolate the mechanism of action by examining the consequence of GEFT expression in multipotent cell lines capable of differentiating into a number of cell types, including muscle and adipocyte lineages. Our data demonstrate that endogenous GEFT is transcriptionally upregulated during myogenic differentiation and downregulated during adipogenic differentiation. Exogenous expression of GEFT promotes myogenesis of C2C12 cells via activation of RhoA, Rac1, and Cdc42 and their downstream effector proteins, while a dominant-negative mutant of GEFT inhibits this process. Moreover, we show that GEFT inhibits insulin-induced adipogenesis in 3T3L1 preadipocytes. In summary, we provide the first evidence that the Rho family signaling pathways act as potential regulators of skeletal muscle regeneration and provide the first reported molecular mechanism illustrating how a mammalian Rho family GEF controls this process by modulating mesenchymal cell fate decisions.

Acute vocal fold wound healing in a rabbit model

Several authors have eloquently described the characteristics of vocal fold scar, a long-term consequence of vocal fold injury. However, events in the acute stage of mucosal injury, which lead up to fibrosis, have been largely overlooked. The current study describes acute events with regard to mucosal re-formation in a rabbit model. Vocal fold injury was induced surgically. A fibrinous clot was present 1 day after injury. Massive cellular infiltration was noted on day 3, and complete epithelial coverage was achieved by day 5. Also, neo-matrix deposition was noted as early as 5 days after injury, and more mature collagen was seen by day 7. The general timetable described in the current study can contribute to the experimental foundation for the development of regenerative models of healing in the vocal folds. Most notably, the proliferation phase of wound healing appears to occur approximately 3 days after injury, indicating a critical time for intervention. Manipulation and/or alteration of naturally occurring neo-matrix deposition and organization may yield improved biophysical function of the injured vocal fold.

Use of nanotopography to study mechanotransduction in fibroblasts--methods and perspectives

The environment around a cell during in vitro culture is unlikely to mimic those in vivo. Preliminary experiments with nanotopography have shown that nanoscale features can strongly influence cell morphology, adhesion, proliferation and gene regulation, but the mechanisms mediating this cell response remain unclear. In this perspective article, we attempt to illustrate that a possible mechanism is direct transmittal of forces encountered by cells during spreading to the nucleus via the cytoskeleton. We further try to illustrate that this 'self-induced' mechanotransduction may alter gene expression by changing interphase chromosome positioning. Whilst the observations described here to show how we think nanotopography can be developed as a tool to look at mechanotransduction are preliminary, we feel they indicate that topography may give cell biologists a non-invasive tool with which to investigate in vitro cellular mechanisms.

Endotoxin inhibits intestinal epithelial restitution through activation of Rho-GTPase and increased focal adhesions

Diseases of gut inflammation such as neonatal necrotizing enterocolitis (NEC) result after an injury to the mucosal lining of the intestine, leading to translocation of bacteria and endotoxin (lipopolysaccharide). Intestinal mucosal defects are repaired by the process of intestinal restitution, during which enterocytes migrate from healthy areas to sites of injury. In an animal model of NEC, we determined that intestinal restitution was significantly impaired compared with control animals. We therefore sought to determine the mechanisms governing enterocyte migration under basal conditions and after an endotoxin challenge. Here we show that the cytoskeletal reorganization and stress fiber formation required for migration in IEC-6 enterocytes requires RhoA. Enterocytes were found to express the endotoxin receptor Toll-like receptor 4, which served to bind and internalize lipopolysaccharide. Strikingly, endotoxin treatment significantly inhibited intestinal restitution, as measured by impaired IEC-6 cell migration across a scraped wound. Lipopolysaccharide was found to increase RhoA activity in a phosphatidylinositol 3-kinase-dependent manner, leading to an increase in phosphorylation of focal adhesion kinase and an enhanced number of focal adhesions. Importantly, endotoxin caused a progressive, RhoA-dependent increase in cell matrix tension/contractility, which correlated with the observed impairment in enterocyte migration. We therefore conclude that endotoxin inhibits enterocyte migration through a RhoA-dependent increase in focal adhesions and enhanced cell adhesiveness, which may participate in the impaired restitution observed in experimental NEC.

Influence of peripheral iridectomy on intravitreous penetration of topical nipradilol

PURPOSE

Penetration of drug from the anterior chamber to the vitreous is substantial in aphakic eyes, but negligible in normal phakic eyes. The purpose of this study is to investigate the effect of the presence of peripheral iridectomy (PI) which bypasses iris-lens diaphragm on the drug penetration from the anterior chamber to the vitreous.

METHODS

Twelve Japanese White rabbits underwent PI in a randomly chosen eye and the same procedures except removal of the peripheral iris in the contralateral eye. Nine weeks after the procedure, topical instillation of 20 microl of 1% nipradilol into the both eyes was repeated three times at five-minute intervals, and two hours later the animals were sacrificed and the both eyes were enucleated. Concentrations of nipradilol in the aqueous and vitreous were determined using a high-performance liquid chromatography.

RESULTS

The concentrations of nipradilol were significantly greater in the eyes with PI than those in the contralateral control eyes in the aqueous (5636 +/- 1688 vs 2835 +/- 663 ng/g, mean +/- standard error, n = 12, p = 0.0028) and in the anterior vitreous (11.9 +/- 2.5 vs 5.6 +/- 1.0 ng/g, p = 0.0047), while not in the posterior vitreous or in the posterior retina-choroid. The ratios of the nipradilol concentrations in the anterior or posterior vitreous to that in the aqueous were not significantly different between the both eyes.

CONCLUSIONS

The presence of PI had little effect on the penetration of topically instilled nipradilol from the anterior chamber to vitreous.