Single-cell Transcriptional Landscape of Temporal Neutrophil Response to Burn Wound in Larval Zebrafish.

Neutrophils accumulate early in tissue injury. However, the cellular and functional heterogeneity of neutrophils during homeostasis and in response to tissue damage remains unclear. In this study, we use larval zebrafish to understand neutrophil responses to thermal injury. Single-cell transcriptional mapping of myeloid cells during a 3-d time course in burn and control larvae revealed distinct neutrophil subsets and their cell-cell interactions with macrophages across time and conditions. The trajectory formed by three zebrafish neutrophil subsets resembles human neutrophil maturation, with varying transition patterns between conditions. Through ligand-receptor cell-cell interaction analysis, we found that neutrophils communicate more in burns in a pathway and temporal manner. Finally, we identified the correlation between zebrafish myeloid signatures and human burn severity, establishing GPR84+ neutrophils as a potential marker of early innate immune response in burns. This work builds a comparative single-cell transcriptomic framework to identify neutrophil markers of tissue damage using model organisms.

The porcine skin microbiome exhibits broad fungal antagonism.

The skin and its microbiome function to protect the host from pathogen colonization and environmental stressors. In this study, using the Wisconsin Miniature Swine™ model, we characterize the porcine skin fungal and bacterial microbiomes, identify bacterial isolates displaying antifungal activity, and use whole-genome sequencing to identify biosynthetic gene clusters encoding for secondary metabolites that may be responsible for the antagonistic effects on fungi. Through this comprehensive approach of paired microbiome sequencing with culturomics, we report the discovery of novel species of Corynebacterium and Rothia. Further, this study represents the first comprehensive evaluation of the porcine skin mycobiome and the evaluation of bacterial-fungal interactions on this surface. Several diverse bacterial isolates exhibit potent antifungal properties against opportunistic fungal pathogens in vitro. Genomic analysis of inhibitory species revealed a diverse repertoire of uncharacterized biosynthetic gene clusters suggesting a reservoir of novel chemical and biological diversity. Collectively, the porcine skin microbiome represents a potential unique source of novel antifungals.

The effect of anatomic location on porcine models of burn injury and wound healing.

Porcine models are frequently used for burn healing studies; however, factors including anatomic location and lack of standardised wound methods can impact the interpretation of wound data. The objectives of this study are to examine the influence of anatomical locations on the uniformity of burn creation and healing in porcine burn models. To optimise burn parameters on dorsal and ventral surfaces, ex vivo and in situ euthanized animals were first used to examine the location-dependence of the burn depth and contact time relationship. The location-dependent healing in vivo was then examined using burn and excisional wounds at dorsal, ventral, caudal and cranial locations. Lactate dehydrogenase (LDH) and H&E were used to assess burn depth and wound re-epithelialization. We found that burn depth on the ventral skin was significantly deeper than that of the dorsal skin at identical thermal conditions. Compared with burns created ex vivo, burns created in situ immediately post-mortem were significantly deeper in the ventral location. In live animals, 2 out of 12 burn wounds were fully re-epithelialized after 14 days in contrast to complete re-epithelialization of all excisional wounds. Among the burn wounds, those at the cranial-dorsal site exhibited faster healing than at the caudal-dorsal site. This study showed that anatomical location is an important consideration for the consistency of burn depth creation and healing. These data support symmetric localization of treatment and control for comparative assessment of burn healing in porcine models to prevent misinterpretation of results and increase the translatability of findings to humans.

What is slough? Defining the proteomic and microbial composition of slough and its implications for wound healing.

Slough is a well-known feature of non-healing wounds. This pilot study aims to determine the proteomic and microbiologic components of slough as well as interrogate the associations between wound slough components and wound healing. Ten subjects with slow-to-heal wounds and visible slough were enrolled. Aetiologies included venous stasis ulcers, post-surgical site infections and pressure ulcers. Patient co-morbidities and wound healing outcome at 3-months post-sample collection was recorded. Debrided slough was analysed microscopically, through untargeted proteomics, and high-throughput bacterial 16S-ribosomal gene sequencing. Microscopic imaging revealed wound slough to be amorphous in structure and highly variable. 16S-profiling found slough microbial communities to associate with wound aetiology and location on the body. Across all subjects, slough largely consisted of proteins involved in skin structure and formation, blood-clot formation and immune processes. To predict variables associated with wound healing, protein, microbial and clinical datasets were integrated into a supervised discriminant analysis. This analysis revealed that healing wounds were enriched for proteins involved in skin barrier development and negative regulation of immune responses. While wounds that deteriorated over time started off with a higher baseline Bates-Jensen Wound Assessment Score and were enriched for anaerobic bacterial taxa and chronic inflammatory proteins. To our knowledge, this is the first study to integrate clinical, microbiome, and proteomic data to systematically characterise wound slough and integrate it into a single assessment to predict wound healing outcome. Collectively, our findings underscore how slough components can help identify wounds at risk of continued impaired healing and serves as an underutilised biomarker.

Burn Resuscitation Practices in North America: Results of the Acute Burn ResUscitation Multicenter Prospective Trial (ABRUPT).

OBJECTIVES: ABRUPT was a prospective, noninterventional, observational study of resuscitation practices at 21 burn centers. The primary goal was to examine burn resuscitation with albumin or crystalloids alone, to design a future prospective randomized trial. SUMMARY BACKGROUND DATA: No modern prospective study has determined whether to use colloids or crystalloids for acute burn resuscitation. METHODS: Patients ≥18 years with burns ≥ 20% total body surface area (TBSA) had hourly documentation of resuscitation parameters for 48 hours. Patients received either crystalloids alone or had albumin supplemented to crystalloid based on center protocols. RESULTS: Of 379 enrollees, two-thirds (253) were resuscitated with albumin and one-third (126) were resuscitated with crystalloid alone. Albumin patients received more total fluid than Crystalloid patients (5.2 ± 2.3 vs 3.7 ± 1.7 mL/kg/% TBSA burn/24 hours), but patients in the Albumin Group were older, had larger burns, higher admission Sequential Organ Failure Assessment (SOFA) scores, and more inhalation injury. Albumin lowered the in-to-out (I/O) ratio and was started ≤12 hours in patients with the highest initial fluid requirements, given >12 hours with intermediate requirements, and avoided in patients who responded to crystalloid alone. CONCLUSIONS: Albumin use is associated with older age, larger and deeper burns, and more severe organ dysfunction at presentation. Albumin supplementation is started when initial crystalloid rates are above expected targets and improves the I/O ratio. The fluid received in the first 24 hours was at or above the Parkland Formula estimate.

Ex Vivo Human and Porcine Skin Effectively Model Candida auris Colonization, Differentiating Robust and Poor Fungal Colonizers.

Candida auris proliferates and persists on the skin of patients, often leading to health care-associated infections with high mortality. Here, we describe 2 clinically relevant skin models and show that C. auris grows similarly on human and porcine skin. Additionally, we demonstrate that other Candida spp., including those with phylogenetic similarity to C. auris, do not display high growth in the skin microenvironment. These studies highlight the utility of 2 ex vivo models of C. auris colonization that allow reproducible differentiation among Candida spp., which should be a useful tool for comparison of C. auris clinical isolates and genetically mutated strains.

Contrasting recruitment of skin-associated adipose depots during cold challenge of mouse and human.

KEY POINTS: Several distinct strategies produce and conserve heat to maintain the body temperature of mammals, each associated with unique physiologies, with consequences for wellness and disease susceptibility Highly regulated properties of skin offset the total requirement for heat production  We hypothesize that the adipose component of skin is primarily responsible for modulating heat flux; here we evaluate the relative regulation of adipose depots in mouse and human, to test their recruitment to heat production and conservation We found that insulating mouse dermal white adipose tissue accumulates in response to environmentally and genetically induced cool stress; this layer is one of two adipose depots closely apposed to mouse skin, where the subcutaneous mammary gland fat pads are actively recruited to heat production In contrast, the body-wide adipose depot associated with human skin produces heat directly, potentially creating an alternative to the centrally regulated brown adipose tissue ABSTRACT: Mammalian skin impacts metabolic efficiency system-wide, controlling the rate of heat loss and consequent heat production. Here we compare the unique fat depots associated with mouse and human skin, to determine whether they have corresponding functions and regulation. For humans, we assay a skin-associated fat (SAF) body-wide depot to distinguish it from the subcutaneous fat pads characteristic of the abdomen and upper limbs. We show that the thickness of SAF is not related to general adiposity; it is much thicker (1.6-fold) in women than men, and highly subject-specific. We used molecular and cellular assays of ß-adrenergic-induced lipolysis and found that dermal white adipose tissue (dWAT) in mice is resistant to lipolysis; in contrast, the body-wide human SAF depot becomes lipolytic, generating heat in response to ß-adrenergic stimulation. In mice challenged to make more heat to maintain body temperature (either environmentally or genetically), there is a compensatory increase in thickness of dWAT: a corresponding ß-adrenergic stimulation of human skin adipose (in vivo or in explant) depletes adipocyte lipid content. We summarize the regulation of skin-associated adipocytes by age, sex and adiposity, for both species. We conclude that the body-wide dWAT depot of mice shows unique regulation that enables it to be deployed for heat preservation; combined with the actively lipolytic subcutaneous mammary fat pads they enable thermal defence. The adipose tissue that covers human subjects produces heat directly, providing an alternative to the brown adipose tissues.

Robbing Peter to Pay Paul: Chlorhexidine gluconate demonstrates short-term efficacy and long-term cytotoxicity.

Wound cleansing agents are routine in wound care and preoperative preparation. Antiseptic activity intends to prevent contaminating microbes from establishing an infection while also raising concerns of cytotoxicity and delayed wound healing. We evaluated the cytotoxicity of five clinically used wound cleaning agents (saline, povidone iodine, Dove® and Dial® soaps, and chlorhexidine gluconate [CHG]) using both an ex vivo and in vivo human skin xenograft mouse model, in contrast to classical in vitro models that lack the structural and compositional heterogeneity of human skin. We further established an ex vivo wound contamination model inoculated with ~100 cells of Pseudomonas aeruginosa or Staphylococcus aureus to evaluate antimicrobial efficacy. Scanning electron microscopy and confocal microscopy were used to evaluate phenotypic and spatial characteristics of bacterial cells in wound tissue. CHG significantly reduced metabolic activity of the skin explants, while all treatments except saline affected local cellular viability. CHG cytotoxicity persisted and progressed over 14 days, impairing wound healing in vivo. Within the contamination model, CHG treatment resulted in a significant reduction of P. aeruginosa wound surface counts at 24 h post-treatment. However, this effect was transient and serial application of CHG had no effect on both P. aeruginosa or S. aureus microbial growth. Microscopy revealed that viable cells of P. aeruginosa reside deep within wound tissue post-CHG application, likely serving as a reservoir to re-populate the tissue to a high bioburden. We reveal concerning cytotoxicity and limited antimicrobial activity of CHG in human skin using clinically relevant models, with the ability to resolve spatial localization and temporal dynamics of tissue viability and microbial growth.

Setting Up for Success: Strategies to Foster Surgeons' Pursuit of Basic Science Research.

BACKGROUND: Surgeons make important contributions to basic science research and are in a unique position to innovate scientifically. The number of surgeons pursuing basic science research has been declining over the past two decades. We sought to describe perceived barriers to surgeons' pursuit of basic science research and identify interventions that mitigate these obstacles. MATERIALS & METHODS: An online survey was sent to chairs of academic surgery departments and practicing surgeons involved in basic science research. A subset of these participants were interviewed about their experiences. Interviews were audio-recorded, transcribed, and uploaded to NVivo. Two coders developed a codebook using inductive content analysis to identify relevant themes. RESULTS: 97 people responded to the survey, 27 (29%) were department chairs. Major barriers to basic science research for all respondents were lack of funding, clinical duties and lack of dedicated time for research. Nine surgeons and three departmental chairs were subsequently interviewed. The importance of having clear research goals and timetables with specific plans for attaining funding were mentioned by all. Chairs described the usefulness of embedding early surgeon scientists in their scientific mentors' labs in a post-doctoral model. Additionally, departmental leaders must actively work to protect surgeon scientists from encroaching clinical and administrative demands. CONCLUSIONS: While barriers to surgeons' pursuit of basic science research exist, the surgeon scientist is a phenotype that can be fostered with the dedication and commitment of surgeons to continue to pursue science research and active support of departmental leadership.

Accelerated complete human skin architecture restoration after wounding by nanogenerator-driven electrostimulation.

BACKGROUND: Electrostimulation (ES) therapy for wound healing is limited in clinical use due to barriers such as cumbersome equipment and intermittent delivery of therapy. METHODS: We adapted a human skin xenograft model that can be used to directly examine the nanogenerator-driven ES (NG-ES) effects on human skin in vivo-an essential translational step toward clinical application of the NG-ES technique for wound healing. RESULTS: We show that NG-ES leads to rapid wound closure with complete restoration of normal skin architecture within 7 days compared to more than 30 days in the literature. NG-ES accelerates the inflammatory phase of wound healing with more rapid resolution of neutrophils and macrophages and enhances wound bed perfusion with more robust neovascularization. CONCLUSION: Our results support the translational evaluation and optimization of the NG-ES technology to deliver convenient, efficient wound healing therapy for use in human wounds.

Indeterminate-Depth Burn Injury-Exploring the Uncertainty.

In the management of indeterminate-depth burns (IDB), common challenges include the ability to predict time to healing and regenerative potential, risk of burn wound progression, and timing of excision. Several technologies exist to aid in determination of the depth of a burn injury, yet surgeons continue to rely on the naked eye-visual assessment-as the standard of care. Newer and improved imaging technologies are closing in on the goal of inexpensive, accurate, noninvasive modalities for depth determination. Likewise, management of IDB is becoming more sophisticated as newer wound healing technologies continue to be developed. By describing what is meant by "indeterminate" depth burns, and their associated challenges, we hope to stimulate interest in research to develop new therapies and management strategies. The ultimate goal is to treat IDB without the need for autografts.

Evolution of ischemia and neovascularization in a murine model of full thickness human wound healing.

Translation of wound healing research is limited by the lack of an appropriate animal model, due to the anatomic and wound healing differences in animals and humans. Here, we characterize healing of grafted, full-thickness human skin in an in vivo model of wound healing. Full-thickness human skin, obtained from reconstructive operations, was grafted onto the dorsal flank of NOD.Cg-KitW41J Tyr + Prkdcscid Il2rgtm1Wjl /ThomJ mice. The xenografts were harvested 1 to 12 weeks after grafting, and histologic analyses were completed for viability, neovascularization, and hypoxia. Visual inspection of the xenograft shows drying and sloughing of the epidermis starting at week four. By week 12, the xenograft appears healed but has lost 63.05 ± 0.24% of the initial graft size. There is histologic evidence of epidermolysis as early as 2 weeks, which progresses until week 4, when new epidermis appears from the wound edges. Epidermal regeneration is complete by week 12, although the epidermis appears hypertrophied. An initial increase of infiltrating immune mouse cells into the xenograft normalizes to baseline 6 months after grafting. Neovascularization, as evidenced by positive staining for the proteins human CD31 and alpha smooth muscle actin, is present as early as 2 weeks after grafting at the interface between the xenograft and the mouse tissue. CD31 and alpha smooth muscle actin staining increased throughout the xenograft over the 12 weeks, leading to greater viability of the tissue. Likewise, there is increased Hypoxia Inducible Factor 1-alpha expression at the interface of viable and nonviable tissue, which suggest a hypoxia-driven process causing early graft loss. These findings illustrate human skin wound healing in an ischemic environment, providing a timeline for use of full thickness human skin after grafting in a murine model to study mechanisms underlying human skin wound healing.

Optical imaging of collagen fiber damage to assess thermally injured human skin.

Surgery is the definitive treatment for burn patients who sustain full-thickness burn injuries. Visual assessment of burn depth is made by the clinician early after injury but is accurate only up to 70% of the time among experienced surgeons. Collagen undergoes denaturation as a result of thermal injury; however, the association of collagen denaturation and cellular death in response to thermal injury is unknown. While gene expression assays and histologic staining allow for ex vivo identification of collagen changes, these methods do not provide spatial or integrity information in vivo. Thermal effects on collagen and the role of collagen in wound repair have been understudied in human burn models due to a lack of methods to visualize both intact and denatured collagen. Hence, there is a critical need for a clinically applicable method to discriminate between damaged and intact collagen fibers in tissues. We present two complementary candidate methods for visualization of collagen structure in three dimensions. Second harmonic generation imaging offers a label-free, high-resolution method to identify intact collagen. Simultaneously, a fluorophore-tagged collagen-mimetic peptide can detect damaged collagen. Together, these methods enable the characterization of collagen damage in human skin biopsies from burn patients, as well as ex vivo thermally injured human skin samples. These combined methods could enhance the understanding of the role of collagen in human wound healing after thermal injury and potentially assist in clinical decision-making.

Discordance between histologic and visual assessment of tissue viability in excised burn wound tissue.

The regenerative capacity of burn wounds, and the need for surgical intervention, depends on wound depth. Clinical visual assessment is considered the gold standard for burn depth assessment but it remains a subjective and inaccurate method for tissue evaluation. The purpose of this study was to compare visual assessment with microscopic and molecular techniques for human burn depth determination, and illustrate differences in the evaluation of tissue for potential regenerative capacity. Using intraoperative visual assessment, patients were identified as having deep partial thickness or full thickness burn wounds. Tangential excisions of burn tissue were processed with hematoxylin and eosin to visualize tissue morphology, lactate dehydrogenase assay to ascertain cellular viability, and Keratin-15 and Ki67 to identify epidermal progenitor cells and proliferative capacity, respectively. RNA from deep partial and full thickness burn tissue as well as normal tissue controls were submitted for RNA sequencing. Lactate dehydrogenase, Keratin-15, and Ki67 were found throughout the excised burn wound tissue in both deep partial thickness burn tissues and in the second tangential excision of full thickness burn tissues. RNA sequencing demonstrated regenerative capacity in both deep partial and full thickness burn tissue, however a greater capacity for regeneration was present in deep partial thickness compared with full thickness burn tissues. In this study, we highlight the discordance that exists between the intraoperative clinical identification of burn injury depth, and microscopic and molecular determination of viability and regenerative capacity. Current methods utilizing visual assessment for depth of injury are imprecise, and can lead to removal of viable tissue. Additionally, hematoxylin and eosin microscopic analysis should not be used as the sole method in research or clinical determination of depth, as there are no differences in staining between viable and nonviable tissue.

Optimization of interstrand interactions enables burn detection with a collagen-mimetic peptide.

Collagen is an abundant component of the extracellular matrix and connective tissues. Some collagen-mimetic peptides (CMPs) that do not form homotrimers can anneal to damaged tissue. Here, through a computational screen, we identify (flpHypGly)7 as an optimal monomeric CMP for heterotrimer formation. We find that (flpHypGly)7 forms stable triple helices with (ProProGly)7 but not with itself. The nonnatural amino acid HflpOH, which is (2S,4S)-4-fluoroproline, is not toxic to human fibroblasts or keratinocytes. Conjugation of (flpHypGly)7 to a fluorescent dye enables the facile detection of burned collagenous tissue with high specificity. The ubiquity of collagen and the prevalence of injuries and diseases that disrupt endogenous collagen suggests widespread utility for this approach.

A simple and improved method to determine cell viability in burn-injured tissue.

BACKGROUND: Cell viability is paramount to wound healing in burn injury. Current methods to determine depth of burn injury in the research setting are based on the subjective visualization of cell viability using hematoxylin and eosin staining. The purpose of this study was to develop a simplified method of lactate dehydrogenase (LDH) staining to identify viable cells in frozen sections of human burn tissue that can be used in the research setting. MATERIALS AND METHODS: After surgical excision, human burn tissue was processed for histologic evaluation. Tissues were fixed and protected with sucrose incubation before cryopreservation. An LDH staining method was developed and evaluated for prolonged stain stability. To evaluate cellular viability in the tissues as demonstrated by enzymatic activity of LDH, digital images of tissue sections were obtained immediately after and 1 mo after staining. RESULTS: The cryopreserved sections of deep partial thickness human burn tissue revealed cellular viability throughout the tissue with the exception of the most superficial region of the tissue. Unlike the hematoxylin and eosin-stained sections, clear demarcation of cellular viability was evident in the LDH-stained sections. CONCLUSIONS: Our simplified protocol identifies, without ambiguity, the viability of the cellular elements in deep partial thickness and full thickness burn injured tissue.

Improving the histologic characterization of burn depth.

BACKGROUND: Visual assessment of burn wound appearance is the standard of care to determine the depth of thermal injury but often incorrectly predicts wound healing potential. Histologic evaluation of hematoxylin and eosin (H&E) stained burn tissue is prone to subjectivity and is challenging for the novice. Lactate dehydrogenase (LDH) staining may offer a simplified and consistent technique to identify burn tissue viability. METHODS: Thirty tissue samples were obtained from 6 patients undergoing surgical excision for clinically determined deep partial thickness or full thickness burns. Tissues were stained with H&E or LDH. Each specimen was scored by 3 individuals with varying levels of skill in histologic interpretation using a standardized checklist at 2 distinct time points. RESULTS: Agreement within raters was highest for the expert rater and lowest for the novice; however, the LDH stained tissue method had improved agreement for an experienced burn surgeon and novice. Agreement between raters was greater for the LDH stained samples which were determined to have greater viability than the corresponding H&E section in 100% of samples scored by the expert and in 80% for the novice clinician. CONCLUSION: LDH staining offers a more consistent measure of tissue viability that can be used by experienced and novice clinicians.

Effect of 2% Chlorhexidine Gluconate-Impregnated Cloth on Surgical Site Infections in Vascular Surgery.

BACKGROUND: Surgical site infections (SSIs) are a significant burden to patients and health care systems. This retrospective study evaluates the observed rates of SSI after our institution implemented chlorhexidine gluconate-impregnated (CHG) cloth as a preoperative antiseptic preparation in elective vascular surgery. METHODS: Between March 2011 and January 2012, we reviewed 250 patients who underwent elective vascular surgery who used the CHG cloth preoperatively. Their rate of SSIs was compared with 252 control patients who received the CHG shower preoperatively during the preintervention period. Urgent and emergent cases were excluded. The primary outcome measured was SSI within 30 days of index operation. RESULTS: There was no baseline difference in mean age, gender distribution, smoking status, diabetes, chronic obstructive pulmonary disease, and the number of patients with body mass index >40 between the cohorts. There was no difference in the overall rate (5.6% vs. 5.6%, P = 1.00) and type of SSIs between the 2 groups, but the control group trended toward deeper infections (4 deep incisional and 2 organ space vs. none and 1, respectively). The control group also had more dirty or infected wound categories (10 vs. 21.4%, P < 0.01) and more perioperative antibiotic errors and hypothermia (P < 0.02). CONCLUSIONS: There was no observed difference in SSI rates before and after implementation of the CHG as the preoperative method of skin decontamination in our retrospective case-control cohorts.

Mechanisms of delayed indocyanine green fluorescence and applications to clinical disease processes.

BACKGROUND: Delayed indocyanine green fluorescence imaging is under investigation in various clinical disease processes. Understanding the mechanisms of indocyanine green accumulation and retention is essential to correctly interpreting and analyzing imaging data. The purpose of this scoping review was to synthesize what is known about the mechanism of indocyanine green retention at the cellular level to better understand the clinical nuances of delayed indocyanine green imaging and identify critical gaps in our knowledge to guide future studies. METHODS: We performed a scoping review of 7,087 citations after performing database searches of PubMed, Scopus, the Cochrane Library, and the Web of Science Core Collection electronic databases. Studies were eligible for inclusion if they were peer-reviewed original research discussing the mechanism of indocyanine green retention in the results section in disease processes involving inflammation and/or necrosis, including cancer, and were available in English. Data were extracted using Covidence software. RESULTS: Eighty-nine studies were included in the final analysis. Several features of indocyanine green retention were identified. CONCLUSION: We identified several mechanistic features involved in indocyanine green accumulation in diseased tissue that overall had distinct mechanisms of indocyanine green retention in tumors, nontumor inflammation, and necrosis. Our study also reveals new insights on how inflammatory infiltrate influences indocyanine green fluorescence imaging. These findings are noteworthy because they add to our understanding of how fluorescence-guided surgery may be optimized based on the pathology of interest via specific indocyanine green dosing and timing of image acquisition.

Single-cell transcriptional landscape of temporal neutrophil response to burn wound in larval zebrafish.

Neutrophils accumulate early in tissue injury. However, the cellular and functional heterogeneity of neutrophils during homeostasis and in response to tissue damage remains unclear. Here, we use larval zebrafish to understand neutrophil responses to thermal injury. Single-cell transcriptional mapping of myeloid cells during a 3-day time course in burn and control larvae revealed distinct neutrophil subsets and their cell-cell interactions with macrophages across time and conditions. The trajectory formed by three zebrafish neutrophil subsets resembles human neutrophil maturation, with varying transition patterns between conditions. Through ligand-receptor cell-cell interaction analysis, we found neutrophils communicate more in burns in a pathway and temporal manner. Finally, we identified the correlation between zebrafish myeloid signatures and human burn severity, establishing GPR84+ neutrophils as a potential marker of early innate immune response in burns. This work builds the molecular foundation and a comparative single-cell genomic framework to identify neutrophil markers of tissue damage using model organisms.