Depletion of Bone Marrow Hematopoietic Cells in Ebolavirus-Infected Rhesus Macaques: A Possible Cause of Hematologic Abnormalities in Ebolavirus Disease.

The pathophysiology of long-recognized hematologic abnormalities in Ebolavirus (EBOV) disease (EVD) is unknown. From limited human sampling (of peripheral blood), it has been postulated that emergency hematopoiesis plays a role in severe EVD, but the systematic characterization of the bone marrow (BM) has not occurred in human disease or in nonhuman primate models. In a lethal rhesus macaque model of EVD, 18 sternal BM samples exposed to the Kikwit strain of EBOV were compared to those from uninfected controls (n = 3). Immunohistochemistry, RNAscope in situ hybridization, transmission electron microscopy, and confocal microscopy showed that EBOV infects BM monocytes/macrophages and megakaryocytes. EBOV exposure was associated with severe BM hypocellularity, including depletion of myeloid, erythroid, and megakaryocyte hematopoietic cells. These depletions were negatively correlated with cell proliferation (Ki67 expression) and were not associated with BM apoptosis during disease progression. In EBOV-infected rhesus macaques with terminal disease, BM showed marked hemophagocytosis, megakaryocyte emperipolesis, and the release of immature hematopoietic cells into the sinusoids. Collectively, these data demonstrate not only direct EBOV infection of BM monocytes/macrophages and megakaryocytes but also that disease progression is associated with hematopoietic failure, notably in peripheral cytopenia. These findings inform current pathophysiologic unknowns and suggest a crucial role for BM dysfunction and/or failure, including emergency hematopoiesis, as part of the natural history of severe human disease.

Sharing the space of the creature: Intersubjectivity as a lens toward mutual human-wildlife dignity.

Human-wildlife coexistence is critical for sustainable and healthy ecosystems as well as to prevent human and wildlife suffering. In this paper, an intersubjective approach to human-wildlife interactions is proposed as a lens toward human decentering and emergent mutual evolution. The thesis is developed through a secondary data analysis of a research study on wildlife care and philosophical analysis using the work of Bernard Lonergan and Edmund Husserl. The study was conducted using the theory of transcendent pluralism, which is grounded in human and ecological dignity, including the dignity of beyond-human beings. Deeper interpretation of the original data suggests that human-wildlife interactions are mutually conscious, embodied, and hold spatial-temporal dimensions. The affective realm is an integral dimension of human-wildlife intersubjectivity. These findings inform an approach toward human-wildlife relations in which human persons and the beyond-human multitude can all flourish in dignity.

Policy education in a research-focused doctoral nursing program: Power as knowing participation in change.

Nurses have moral obligations incurred by membership in the profession to participate knowingly in health policy advocacy. Many barriers have historically hindered nurses from realizing their potential to advance health policy. The contemporary political context sets additional challenges to policy work due to polarization and conflict. Nursing education can help nurses recognize their role in advancing health through political advocacy in a manner that is consistent with disciplinary knowledge and ethical responsibilities. In this paper, the authors describe an exemplar of Elizabeth Barrett's "Power as Knowing Participation in Change" theory as a disciplinary lens within a doctoral nursing health policy course. Barrett (radically) emphasizes "power as freedom" instead of "power as control." This approach is congruent with nursing disciplinary values and enhances awareness of personal freedom and building collaborative relationships in the policy process. The theory was used in concert with other traditional policy content and frameworks from nursing and other disciplines. We discuss the role of nursing ethics viewed as professional responsibility for policy action, an overview of Barrett's theory, and the design of the course. Four student reflections on how the course influenced their thinking about policy advocacy are included. While not specific to policymaking, Barrett's theory provides a disciplinary grounding to increase students' awareness of freedom and choices in political advocacy participation. Our experience suggests that Barrett's work can be fruitful for enhancing nurses' awareness of choices to participate in change across settings.

Ebola Virus Disease Features Hemophagocytic Lymphohistiocytosis/Macrophage Activation Syndrome in the Rhesus Macaque Model.

BACKGROUND: Ebola virus (EBOV) disease (EVD) is one of the most severe and fatal viral hemorrhagic fevers and appears to mimic many clinical and laboratory manifestations of hemophagocytic lymphohistiocytosis syndrome (HLS), also known as macrophage activation syndrome. However, a clear association is yet to be firmly established for effective host-targeted, immunomodulatory therapeutic approaches to improve outcomes in patients with severe EVD. METHODS: Twenty-four rhesus monkeys were exposed intramuscularly to the EBOV Kikwit isolate and euthanized at prescheduled time points or when they reached the end-stage disease criteria. Three additional monkeys were mock-exposed and used as uninfected controls. RESULTS: EBOV-exposed monkeys presented with clinicopathologic features of HLS, including fever, multiple organomegaly, pancytopenia, hemophagocytosis, hyperfibrinogenemia with disseminated intravascular coagulation, hypertriglyceridemia, hypercytokinemia, increased concentrations of soluble CD163 and CD25 in serum, and the loss of activated natural killer cells. CONCLUSIONS: Our data suggest that EVD in the rhesus macaque model mimics pathophysiologic features of HLS/macrophage activation syndrome. Hence, regulating inflammation and immune function might provide an effective treatment for controlling the pathogenesis of acute EVD.

Expanded Histopathology and Tropism of Ebola Virus in the Rhesus Macaque Model: Potential for Sexual Transmission, Altered Adrenomedullary Hormone Production, and Early Viral Replication in Liver.

The pathogenesis of Ebola virus disease (EVD) is still incomplete, in spite of the availability of a nonhuman primate modelfor more than 4 decades. To further investigate EVD pathogenesis, a natural history study was conducted using 27 Chinese-origin rhesus macaques. Of these, 24 macaques were exposed intramuscularly to Kikwit Ebola virus and euthanized at predetermined time points or when end-stage clinical disease criteria were met, and 3 sham-exposed macaques were euthanized on study day 0. This study showed for the first time that Ebola virus causes uterine cervicitis, vaginitis, posthitis, and medullary adrenalitis. Not only was Ebola virus detected in the interstitial stromal cells of the genital tract, but it was also present in the epididymal and seminal vesicular tubular epithelial cells, ectocervical and vaginal squamous epithelial cells, and seminal fluid. Furthermore, as early as day 3 after exposure, Ebola virus replicative intermediate RNA was detected in Kupffer cells and hepatocytes. These findings in the nonhuman model provide additional insight into potential sexual transmission, possible disruption of sympathetic hormone production, and early virus replication sites in human EVD patients.

Filoviruses Infect Rhesus Macaque Synoviocytes in Vivo and Primary Human Synoviocytes in Vitro.

The most commonly reported symptom of post-Ebola virus disease syndrome in survivors is arthralgia, yet involvement of the joints in acute or convalescent Ebola virus infection is not well characterized in human patients or animal models. Through immunohistochemistry, we found that the lining synovial intima of the stifle (knee) is a target for acute infection by Ebola virus/Kikwit, Ebola virus/Makona-C05, and Marburg virus/Angola in the rhesus macaque model. Furthermore, histologic analysis, immunohistochemistry, RNAscope in situ hybridization, and transmission electron microscopy showed that synoviocytes of the stifle, shoulder, and hip are a target for mouse-adapted Ebola virus/Yambuku-Mayinga infection during acute disease in rhesus macaques. A time course of infection study with Ebola virus/Kikwit found that the large joint synovium became immunopositive beginning on postinfection day 6. In total, the synovium of 28 of 30 rhesus macaques with terminal filovirus disease had evidence of infection (64 of 96 joints examined). On the basis of immunofluorescence, infected cell types included CD68+ type A (macrophage-like) synoviocytes and CD44+ type B (fibroblast-like) synoviocytes. Cultured primary human fibroblast-like synoviocytes were permissive to infection with Ebola and Marburg viruses in vitro. Because synovial joints include immune privileged sites, these findings are significant for future investigations of filovirus pathogenesis and persistence as well as arthralgias in acute and convalescent filovirus disease.

Peripheral Neuronopathy Associated With Ebola Virus Infection in Rhesus Macaques: A Possible Cause of Neurological Signs and Symptoms in Human Ebola Patients.

Neurological signs and symptoms are the most common complications of Ebola virus disease. However, the mechanisms underlying the neurologic manifestations in Ebola patients are not known. In this study, peripheral ganglia were collected from 12 rhesus macaques that succumbed to Ebola virus (EBOV) disease from 5 to 8 days post exposure. Ganglionitis, characterized by neuronal degeneration, necrosis, and mononuclear leukocyte infiltrates, was observed in the dorsal root, autonomic, and enteric ganglia. By immunohistochemistry, RNAscope in situ hybridization, transmission electron microscopy, and confocal microscopy, we confirmed that CD68+ macrophages are the target cells for EBOV in affected ganglia. Further, we demonstrated that EBOV can induce satellite cell and neuronal apoptosis and microglial activation in infected ganglia. Our results demonstrate that EBOV can infect peripheral ganglia and results in ganglionopathy in rhesus macaques, which may contribute to the neurological signs and symptoms observed in acute and convalescent Ebola virus disease in human patients.

Persistence of Lassa Virus Associated With Severe Systemic Arteritis in Convalescing Guinea Pigs (Cavia porcellus).

Lassa fever (LF) survivors develop various clinical manifestations including polyserositis, myalgia, epididymitis, and hearing loss weeks to months after recovery from acute infection. We demonstrate a systemic lymphoplasmacytic and histiocytic arteritis and periarteritis in guinea pigs more than 2 months after recovery from acute Lassa virus (LASV) infection. LASV was detected in the arterial tunica media smooth muscle cells by immunohistochemistry, in situ hybridization, and transmission electron microscopy. Our results suggest that the sequelae of LASV infection may be due to virus persistence resulting in systemic vascular damage. These findings shed light on the pathogenesis of LASV sequelae in convalescent human survivors.

Ebola Virus Localization in the Macaque Reproductive Tract during Acute Ebola Virus Disease.

Sexual transmission of Ebola virus (EBOV) has been demonstrated more than a year after recovery from the acute phase of Ebola virus disease (EVD). The mechanisms underlying EBOV persistence and sexual transmission are not currently understood. Using the acute macaque model of EVD, we hypothesized EBOV would infect the reproductive tissues and sought to localize the infection in these tissues using immunohistochemistry and transmission electron microscopy. In four female and eight male macaques that succumbed to EVD between 6 and 9 days after EBOV challenge, we demonstrate widespread EBOV infection of the interstitial tissues and endothelium in the ovary, uterus, testis, seminal vesicle, epididymis, and prostate gland, with minimal associated tissue immune response or organ pathology. Given the widespread involvement of EBOV in the reproductive tracts of both male and female macaques, it is reasonable to surmise that our understanding of the mechanisms underlying sexual transmission of EVD and persistence of EBOV in immune-privileged sites would be facilitated by the development of a nonhuman primate model in which the macaques survived past the acute stage into convalescence.

Ethical challenges experienced by clinical research nurses:: A qualitative study.

BACKGROUND:: Clinical investigation is a growing field employing increasing numbers of nurses. This has created a new specialty practice defined by aspects unique to nursing in a clinical research context: the objectives (to implement research protocols and advance science), setting (research facilities), and nature of the nurse-participant relationship. The clinical research nurse role may give rise to feelings of ethical conflict between aspects of protocol implementation and the duty of patient advocacy, a primary nursing responsibility. Little is known about whether research nurses experience unique ethical challenges distinct from those experienced by nurses in traditional patient-care settings. RESEARCH OBJECTIVES:: The purpose of the study was to describe the nature of ethical challenges experienced by clinical research nurses within the context of their practice. RESEARCH DESIGN:: The study utilized a qualitative descriptive design with individual interviews. PARTICIPANTS AND RESEARCH CONTEXT:: Participating nurses (N = 12) self-identified as having experienced ethical challenges during screening. The majority were Caucasian (90%), female (83%), and worked in outpatient settings (67%). Approximately 50% had > 10 years of research experience. ETHICAL CONSIDERATIONS:: The human subjects review board approved the study. Written informed consent was obtained. FINDINGS:: Predominant themes were revealed: (1) the inability to provide a probable good, or/do no harm, and (2) dual obligations (identity as a nurse vs a research nurse). The following patterns and subthemes emerged: conflicted allegiances between protocol implementation, needs of the participant, desire to advance science, and tension between the nurse-patient therapeutic relationship versus the research relationship. DISCUSSION:: Participants described ethical challenges specific to the research role. The issues are central to the nurse-participant relationship, patient advocacy, the nurse's role in implementing protocols, and/or advancing science. CONCLUSION:: Ethical challenges related to the specialized role of clinical research nurses were identified. More research is warranted to fully understand their nature and frequency and to identify support systems for resolution.

Expanding horizons: Lonergan's philosophy as a guide to PhD program pedagogy.

Historically, research-focused doctoral programs in nursing have used the apprenticeship model to educate and prepare nurse scientists for research careers. The assumption is that students learn best when paired with a faculty member who is working on the same topic. This model works well when there is a stable workforce, adequate funding streams and sufficient faculty with diverse expertise to capture the enthusiasm and varied topics of incoming doctoral students. However, we believe there are alternative approaches that are worth exploring. We propose an alternative way of preparing students for entry into nursing science. The purpose of this paper is to describe one PhD program's new approach, based on the philosophical premises of Bernard Lonergan, to create a generation of creative, insightful thinkers who expand the horizons of the nursing discipline.

An Inactivated Rabies Virus-Based Ebola Vaccine, FILORAB1, Adjuvanted With Glucopyranosyl Lipid A in Stable Emulsion Confers Complete Protection in Nonhuman Primate Challenge Models.

The 2013-2016 West African Ebola virus (EBOV) disease outbreak was the largest filovirus outbreak to date. Over 28 000 suspected, probable, or confirmed cases have been reported, with a 53% case-fatality rate. The magnitude and international impact of this EBOV outbreak has highlighted the urgent need for a safe and efficient EBOV vaccine. To this end, we demonstrate the immunogenicity and protective efficacy of FILORAB1, a recombinant, bivalent, inactivated rabies virus-based EBOV vaccine, in rhesus and cynomolgus monkeys. Our results demonstrate that the use of the synthetic Toll-like receptor 4 agonist glucopyranosyl lipid A in stable emulsion (GLA-SE) as an adjuvant increased the efficacy of FILORAB1 to 100% protection against lethal EBOV challenge, with no to mild clinical signs of disease. Furthermore, all vaccinated subjects developed protective anti-rabies virus antibody titers. Taken together, these results support further development of FILORAB1/GLA-SE as an effective preexposure EBOV vaccine.

Exposure of rhesus monkeys to cowpox virus Brighton Red by large-particle aerosol droplets results in an upper respiratory tract disease.

We previously demonstrated that small-particle (0.5-3.0 µm) aerosol infection of rhesus monkeys (Macaca mulatta) with cowpox virus (CPXV)-Brighton Red (BR) results in fulminant respiratory tract disease characterized by severe lung parenchymal pathology but only limited systemic virus dissemination and limited classic epidermal pox-like lesion development (Johnson et al., 2015). Based on these results, and to further develop CPXV as an improved model of human smallpox, we evaluated a novel large-particle aerosol (7.0-9.0 µm) exposure of rhesus monkeys to CPXV-BR and monitored for respiratory tract disease by serial computed tomography (CT). As expected, the upper respiratory tract and large airways were the major sites of virus-induced pathology following large-particle aerosol exposure. Large-particle aerosol CPXV exposure of rhesus macaques resulted in severe upper airway and large airway pathology with limited systemic dissemination.

What we're trying to solve: the back and forth of engaged interdisciplinary inquiry.

Interdisciplinary research assumes that teams of highly specialized scientists develop new knowledge by bridging their respective horizons. Nurse educators preparing nursing doctoral students to conduct interdisciplinary research need insight into how members of interdisciplinary research teams experience knowledge horizons in these complex contexts. Based on the work of the philosopher Bernard Lonergan, this pilot study uses Transcendental Method for Research with Human Subjects to explore interdisciplinary researchers' experiences with and attitudes toward interdisciplinary research. Results reveal the overarching conceptual category of "engaged interdisciplinary inquiry" which includes six themes: (i) valuing interdisciplinary engagement; (ii) direct engagement; (iii) interior engagement; (iv) disengagement; (v) facilitated engagement and (vi) engaged researcher development. Results also suggest engagement depends on vigorous "back and forth", or dialogue, with self and others, and demonstrate the study method is fruitful for cognitive inquiry. This pilot supports expanded study to inform preparation for and conduct of interdisciplinary research involving nurses and raises important questions about how the trend toward interdisciplinary research affects nursing science.

The feasibility of wildlife immersion experiences for Veterans with PTSD.

Introduction: Animal-assisted interventions (AAI) offer potential physical and psychological health benefits that may assist Veterans with post-traumatic stress disorder. However, more feasibility studies are needed regarding intervention details, adverse events, reasons for study withdrawal, and animal welfare. Methods: This mixed methods feasibility trial involved a modified crossover study in which Veterans with PTSD/PTSD symptoms were provided a series of 8 nature and wildlife immersion experiences to evaluate feasibility and preliminary efficacy. The sample included 19 Veterans with PTSD/PTSD symptoms who were followed for a mean of 15.1 weeks. The intervention was comprised of a baseline forest walk, assisting with wildlife rehabilitation, observation in a wildlife sanctuary, and bird watching. Post study bird feeders were provided for sustainability. Results: This AAI nature/wildlife immersion intervention was feasible, acceptable, and safe to administer to Veterans with PTSD/PTSD symptoms with appropriate support. Logistical and relational facilitators were identified that supported the wildlife immersion activities. Participants reported greatly enjoying the activities. Attention to animal welfare and care was an important ethical foundation that also contributed to feasibility. Discussion: AAI immersion experiences with wildlife are feasible and can safely be administered to Veterans with PTSD/PTSD symptoms. Logistical and relational facilitators are important to support nature and wildlife immersion activities.

Evaluation of a panel of therapeutic antibody clinical candidates for efficacy against SARS-CoV-2 in Syrian hamsters.

The COVID-19 pandemic spurred the rapid development of a range of therapeutic antibody treatments. As part of the US government's COVID-19 therapeutic response, a research team was assembled to support assay and animal model development to assess activity for therapeutics candidates against SARS-CoV-2. Candidate treatments included monoclonal antibodies, antibody cocktails, and products derived from blood donated by convalescent patients. Sixteen candidate antibody products were obtained directly from manufacturers and evaluated for neutralization activity against the WA-01 isolate of SARS-CoV-2. Products were further tested in the Syrian hamster model using prophylactic (-24 h) or therapeutic (+8 h) treatment approaches relative to intranasal SARS-CoV-2 exposure. In vivo assessments included daily clinical scores and body weights. Viral RNA and viable virus titers were quantified in serum and lung tissue with histopathology performed at 3d and 7d post-virus-exposure. Sham-treated, virus-exposed hamsters showed consistent clinical signs with concomitant weight loss and had detectable viral RNA and viable virus in lung tissue. Histopathologically, interstitial pneumonia with consolidation was present. Therapeutic efficacy was identified in treated hamsters by the absence or diminution of clinical scores, body weight loss, viral loads, and improved semiquantitative lung histopathology scores. This work serves as a model for the rapid, systematic in vitro and in vivo assessment of the efficacy of candidate therapeutics at various stages of clinical development. These efforts provided preclinical efficacy data for therapeutic candidates. Furthermore, these studies were invaluable for the phenotypic characterization of SARS CoV-2 disease in hamsters and of utility to the broader scientific community.

Longitudinal analyses using 18F-Fluorodeoxyglucose positron emission tomography with computed tomography as a measure of COVID-19 severity in the aged, young, and humanized ACE2 SARS-CoV-2 hamster models.

This study compared disease progression of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in three different models of golden hamsters: aged (≈60 weeks old) wild-type (WT), young (6 weeks old) WT, and adult (14-22 weeks old) hamsters expressing the human-angiotensin-converting enzyme 2 (hACE2) receptor. After intranasal (IN) exposure to the SARS-CoV-2 Washington isolate (WA01/2020), 2-deoxy-2-[fluorine-18]fluoro-D-glucose positron emission tomography with computed tomography (18F-FDG PET/CT) was used to monitor disease progression in near real time and animals were euthanized at pre-determined time points to directly compare imaging findings with other disease parameters associated with coronavirus disease 2019 (COVID-19). Consistent with histopathology, 18F-FDG-PET/CT demonstrated that aged WT hamsters exposed to 105 plaque forming units (PFU) developed more severe and protracted pneumonia than young WT hamsters exposed to the same (or lower) dose or hACE2 hamsters exposed to a uniformly lethal dose of virus. Specifically, aged WT hamsters presented with a severe interstitial pneumonia through 8 d post-exposure (PE), while pulmonary regeneration was observed in young WT hamsters at that time. hACE2 hamsters exposed to 100 or 10 PFU virus presented with a minimal to mild hemorrhagic pneumonia but succumbed to SARS-CoV-2-related meningoencephalitis by 6 d PE, suggesting that this model might allow assessment of SARS-CoV-2 infection on the central nervous system (CNS). Our group is the first to use (18F-FDG) PET/CT to differentiate respiratory disease severity ranging from mild to severe in three COVID-19 hamster models. The non-invasive, serial measure of disease progression provided by PET/CT makes it a valuable tool for animal model characterization.

Rare, convergent antibodies targeting the stem helix broadly neutralize diverse betacoronaviruses.

Humanity has faced three recent outbreaks of novel betacoronaviruses, emphasizing the need to develop approaches that broadly target coronaviruses. Here, we identify 55 monoclonal antibodies from COVID-19 convalescent donors that bind diverse betacoronavirus spike proteins. Most antibodies targeted an S2 epitope that included the K814 residue and were non-neutralizing. However, 11 antibodies targeting the stem helix neutralized betacoronaviruses from different lineages. Eight antibodies in this group, including the six broadest and most potent neutralizers, were encoded by IGHV1-46 and IGKV3-20. Crystal structures of three antibodies of this class at 1.5-1.75-Å resolution revealed a conserved mode of binding. COV89-22 neutralized SARS-CoV-2 variants of concern including Omicron BA.4/5 and limited disease in Syrian hamsters. Collectively, these findings identify a class of IGHV1-46/IGKV3-20 antibodies that broadly neutralize betacoronaviruses by targeting the stem helix but indicate these antibodies constitute a small fraction of the broadly reactive antibody response to betacoronaviruses after SARS-CoV-2 infection.

Effect of dietary polyunsaturated fatty acids on castration-resistant Pten-null prostate cancer.

A common treatment of advanced prostate cancer involves the deprivation of androgens. Despite the initial response to hormonal therapy, eventually all the patients relapse. In the present study, we sought to determine whether dietary polyunsaturated fatty acid (PUFA) affects the development of castration-resistant prostate cancer. Cell culture, patient tissue microarray, allograft, xenograft, prostate-specific Pten knockout and omega-3 desaturase transgenic mouse models in conjunction with dietary manipulation, gene knockdown and knockout approaches were used to determine the effect of dietary PUFA on castration-resistant Pten-null prostate cancer. We found that deletion of Pten increased androgen receptor (AR) expression and Pten-null prostate cells were castration resistant. Omega-3 PUFA slowed down the growth of castration-resistant tumors as compared with omega-6 PUFA. Omega-3 PUFA decreased AR protein to a similar extent in tumor cell cytosolic and nuclear fractions but had no effect on AR messenger RNA level. Omega-3 PUFA treatment appeared to accelerate AR protein degradation, which could be blocked by proteasome inhibitor MG132. Knockdown of AR significantly slowed down prostate cancer cell proliferation in the absence of androgens. Our data suggest that omega-3 PUFA inhibits castration-resistant prostate cancer in part by accelerating proteasome-dependent degradation of the AR protein. Dietary omega-3 PUFA supplementation in conjunction with androgen ablation may significantly delay the development of castration-resistant prostate cancer in patients compared with androgen ablation alone.

Electrical stimulation increases blood flow and haemoglobin levels in acute cutaneous wounds without affecting wound closure time: evidenced by non-invasive assessment of temporal biopsy wounds in human volunteers.

Recent studies highlighted the beneficial effects of a novel electrical stimulation waveform, the degenerate wave (DW), on skin fibroblasts and symptomatic skin scarring. However, no study to date has investigated the role of DW on acute cutaneous wounds. Therefore, we evaluated this in a trial using a temporal punch biopsy model. Twenty healthy volunteers had a biopsy performed on day 0 (left arm) and day 14 (right arm). On day 14, DW was applied. Participants were randomised into two groups. Objective non-invasive assessments were performed on days 0, 7, 14, 60 and 90 using spectrophotometric intracutaneous analysis and full-field laser perfusion imaging. There were statistically significant increases in mean flux on day 14 (P = 0.027) in the post-DW arm. Haemoglobin levels increased on day 7 for the post-DW arm compared to without DW (P = 0.088). Differences in melanin levels were higher post-DW on the left arm between randomised groups on day 90 (P = 0.033). Haemoglobin levels in the vascular ring increased significantly from day 7 to 90 (P < 0.001 for post-DW and without DW arms). This study, for the first time, shows that DW increases blood flow and haemoglobin levels in acute healing wounds without affecting wound closure time and may have potential application in enhancing acute cutaneous healing.