Noninvasive device readouts validated by immunohistochemical analysis enable objective quantitative assessment of acute wound healing in human skin

InCISE: Instrument for Comprehensive Incisional and Surgical Evaluation

OBJECTIVE

The evaluation of healing after head and neck surgery is currently qualitative and non-standardized, limiting the quality of surgical healing assessments in clinical and research settings. We sought to develop an objective, standardized wound assessment score, and hypothesize that a reliable instrument can be developed to evaluate head and neck surgical wounds.

METHODS

A prospective cohort study was conducted in a tertiary-care, academic head and neck surgery practice. Patients undergoing head and neck surgery were enrolled. A digital photograph protocol was developed for evaluating healing surgical wounds. A panel of experts developed and refined a wound healing score and established reliability, reproducibility, internal consistency, and validity of the score.

RESULTS

InCISE: Instrument for comprehensive incisional and surgical evaluation was created. The utility of our wound healing score was assessed using classical test theory. We performed the major steps of establishing reliability in head and neck surgeons: (1) internal consistency (Cronbach's α = 0.81), (2) inter-observer reliability (intra-class correlation = 0.76), and (3) intra-rater reliability (intra-class correlation = 0.87), and content validity (through focus groups). Our composite measure was found to have strong internal consistency, inter-rater reliability, and intra-rater reliability. Preliminary work suggests criterion validity via associations with physical health related quality of life (SF-12).

CONCLUSION

A wound healing score for head and neck surgery, InCISE, has been developed and is reliable, reproducible, and consistent. Although content validity is present and criterion validity is suggested, work continues to establish validity in this instrument to allow for expanded clinical and research use.

LEVEL OF EVIDENCE

NA Laryngoscope, 133:2166-2173, 2023.

Impact of Portuguese propolis on keratinocyte proliferation, migration and ROS protection: Significance for applications in skin products

OBJECTIVE

Propolis has been used since antiquity, but recent reports of its biological properties hint that it could be employed as a topical pharmaceutical and cosmetic ingredient. This work aims to probe the action of Portuguese propolis extracts on skin cells, providing mechanistic insights into its mode of action and preliminarily assessing its applicability as a skin repair ingredient.

METHODS

The total phenolic content of propolis extracts was measured by the Folin Ciocalteu method. The cytotoxic effect of propolis extracts in human keratinocytes was determined and non-cytotoxic concentrations of the extracts were used to study the impact on collective cell migration, cell cycle and intracellular ROS levels.

RESULTS

o significant impact was observed in collective cell migration, but one of the extracts mildly increased G2 phase while reducing the % of sub-G1 at a non-cytotoxic concentration. The two extracts with higher phenolic content strongly prevented intracellular cellular ROS accumulation upon exposure to TBHP. Collectively, these results indicate that the putative beneficial effects of propolis extracts in skin repair may not be attributable to induction of collective cell migration but could be partially ascribed to the protection from oxidative stress, which could act in synergy with its well-known antimicrobial activity.

CONCLUSION

These data support the applicability of this material in topical and cosmetic formulations and further in vivo assays should be conducted to fully characterize its efficacy and safety.

Noninvasive Objective Tools for Quantitative Assessment of Skin Scarring

Significance: Many treatments are utilized in the management of skin scarring; however, difficulties arise due to the high rates of recurrence and the identification of treatment efficacy in each patient, in particular, in the case of raised dermal scarring. Therefore, evaluation of treatments and the provision of objective scar assessment pre-therapy and post-therapy is of paramount importance to identify changes in scar characteristics using noninvasive devices. Recent Advances: There have been a number of emerging noninvasive objective quantitative devices, which assess specific scar parameters such as pliability, volume, color, perfusion, and depth. These can include three-dimensional imaging, optical coherence tomography, in vivo confocal microscopy, full-field laser perfusion imaging, and spectrophotometric intracutaneous analysis. Critical Issues: Clinical assessment and grading scales are most commonly used to assess scarring; however, there is a need for more objective quantitative measures to monitor their maturation and response to therapy. Currently, there is no consensus as to which objective measuring device is most optimal when assessing skin scarring. There is a need for a predictor tool that allows early implementation of treatment and addresses diagnosis, therapy, and prognosis. Future Directions: Validation of noninvasive objective scar assessment tools is essential as well as further development of technologies. There are currently more modalities that assess physical scar characteristics and only few that measure the physiological parameters. Therefore, the development of a technology that quantifies the metabolic and cellular activity in skin scars is necessary to allow for bespoke strategies for each patient.

Classification of Distinct Endotypes in Human Skin Scarring: S.C.A.R.-A Novel Perspective on Dermal Fibrosis

Significance: Skin scarring is a permanent, irreversible end point of cutaneous injury. However, not everyone will acquire the same exact scar type. Skin scarring is generally recognized as complex with significant variability in individuals' scar type and response to treatment. Despite these tangible differences in treatment response, to date there has been no simplified approach in defining spectrum of skin scarring in relation to prediction and outcome post-treatment. Thus, in this study we propose that skin scarring consists of distinct endotypes, which is characterized by their specific pathology. Four distinct scar endotypes can be observed: (1) Stretched (flat), (2) Contracted, (3) Atrophic (depressed), and (4) Raised scarring, which can be abbreviated to S.C.A.R. endotypes. Each of these endotypes can certainly include subphenotypes and each phenotype can be present in more than one endotype. To define these endotypes, we also present a structured approach in assessment of all relevant parameters in skin scar evaluation including clinical (scar symptoms and signs) and nonclinical parameters (device measurements of structural, mechanical, and physiological properties of scars as well as gene and protein laboratory studies). Recent Advances: Scars can be phenotypically characterized based on a multitude of parameters assessed; however, not all scar types will share all the same characteristics. This leads to the question of whether skin scarring is a single disease entity with varying phenotypic characteristics or should be classed as several disease entities that have certain similar parameters. We suggest the latter and propose distinct scarring phenotypes arise mainly owing to genetic and environmental susceptibilities associated with the development of each specific scar endotype. Characteristic features of skin scarring, however, can be objectively and quantitively evaluated and used as an aid in the theranostic goal-directed management of scarring. Critical Issues: The concept of identifying different endotypes is key in formulating personalized treatments with improved outcomes beyond what is achieved with current nonspecific approaches in scar management. This approach has gained interest and significant traction in several other medical conditions including asthma, rheumatoid arthritis, and atopic dermatitis. Future Directions: To begin identifying distinct endotypic features in skin scarring, it is important to have a better understanding of underlying pathological mechanisms leading to further insight into the heterogeneous nature of skin scarring endotypes. This approach may lead to improved theranostic outcomes and further understanding of the pathophysiology of the complex nature of human skin scarring.

Scientific validation of three-dimensional stereophotogrammetry compared to the IGAIS clinical scale for assessing wrinkles and scars after laser treatment

Measuring outcomes from treatments to the skin is either reliant upon patient’s subjective feedback or scale-based peer assessments. Three-Dimensional stereophotogrammetry intend to accurately quantify skin microtopography before and after treatments. The objective of this study is comparing the accuracy of stereophotogrammetry with a scale-based peer evaluation in assessing topographical changes to skin surface following laser treatment. A 3D stereophotogrammetry system photographed skin surface of 48 patients with facial wrinkles or scars before and three months after laser resurfacing, followed immediately by topical application of vitamin C. The software measured changes in skin roughness, wrinkle depth and scar volume. Images were presented to three observers, each independently scoring cutaneous improvement according to Investigator Global Aesthetic Improvement Scale (IGAIS). As for the results, a trend reflecting skin/scar improvement was reported by 3D SPM measurements and raters. The percentage of topographical change given by the raters matched 3D SPM findings. Agreement was highest when observers analysed 3D images. However, observers overestimated skin improvement in a nontreatment control whilst 3D SPM was precise in detecting absence of intervention. This study confirmed a direct correlation between the IGAIS clinical scale and 3D SPM and confirmed the efficacy and accuracy of the latter when assessing cutaneous microtopography alterations as a response to laser treatment.

Lesional skin in vitiligo exhibits delayed in vivo reepithelialization compared to the nonlesional skin

Vitiligo, a common skin disorder, is characterized by the loss of functional melanocytes resulting in the depigmentation of skin. Previous studies have demonstrated molecular and architectural alterations in the epidermal keratinocytes upon loss of melanocytes. The physiological implications of these "altered" keratinocytes are yet not known. We investigated the wound healing efficiency of lesional vs nonlesional skin in 12 subjects with stable nonsegmental vitiligo using histological and ultrastructural evaluation of partial-thickness wounds. The wounds were examined 12 days postinjury, coinciding with the reepithelialization phase of healing marked primarily by keratinocyte migration and proliferation. This study demonstrated a significant difference in the reepithelialization potential between the lesional and nonlesional skin. While all 12 nonlesional wounds demonstrated considerable neoepidermis formation on the 12th day post wound, only four of the corresponding lesional samples showed comparable reepithelialization; the rest remaining in the inflammatory phase. Ultrastructural studies using transmission electron microscopy as well as immunohistochemical staining revealed a reduced number of desmosomes, shorter keratin tonofilaments and an increase in myofibroblast population in the dermis of lesional reepithelialized tissue compared to the nonlesional reepithelialized samples. This study implicates gross functional perturbations in the lesional skin during physiological wound healing in vitiligo, suggesting that the breakdown of keratinocyte-melanocyte network results in delayed wound repair kinetics in the lesional skin when compared to patient-matched nonlesional skin.

Quantitative Methods for Measuring Repair Rates and Innate-Immune Cell Responses in Wounded Mouse Skin

In skin wounds, innate-immune cells clear up tissue debris and microbial contamination, and also secrete cytokines and other growth factors that impact repair process such as re-epithelialization and wound closure. After injury, there is a rapid influx and efflux of immune cells at wound sites, yet the function of each innate cell population in skin repair is still under investigation. Flow cytometry is a valuable research tool for detecting and quantifying immune cells; however, in mouse back skin, the difficulty in extracting immune cells from small area of skin due to tissue complexity has made cytometric analysis an underutilized tool. In this paper, we provide detailed methods on the digestion of lesion-specific skin without disrupting antigen expression followed by multiplex cell staining that allows for identification of seven innate-immune populations, including rare subsets such as group-3 innate lymphoid cells (ILC3s), by flow-cytometry analysis. Furthermore, when studying the functions of immune cells to tissue repair an important metric to monitor is size of the wound opening. Normal wounds close steadily albeit at non-linear rates, while slow or stalled wound closure can indicate an underlying problem with the repair process. Calliper measurements are difficult and time-consuming to obtain and can require repeated sedation of experimental animals. We provide advanced methods for measuring of wound openness; digital 3D image capture and semi-automated image processing that allows for unbiased, reliable measurements that can be taken repeatedly over time.