Pulmonary Vascular Endothelialitis, Thrombosis, and Angiogenesis in Covid-19.

BACKGROUND: Progressive respiratory failure is the primary cause of death in the coronavirus disease 2019 (Covid-19) pandemic. Despite widespread interest in the pathophysiology of the disease, relatively little is known about the associated morphologic and molecular changes in the peripheral lung of patients who die from Covid-19. METHODS: We examined 7 lungs obtained during autopsy from patients who died from Covid-19 and compared them with 7 lungs obtained during autopsy from patients who died from acute respiratory distress syndrome (ARDS) secondary to influenza A(H1N1) infection and 10 age-matched, uninfected control lungs. The lungs were studied with the use of seven-color immunohistochemical analysis, micro-computed tomographic imaging, scanning electron microscopy, corrosion casting, and direct multiplexed measurement of gene expression. RESULTS: In patients who died from Covid-19-associated or influenza-associated respiratory failure, the histologic pattern in the peripheral lung was diffuse alveolar damage with perivascular T-cell infiltration. The lungs from patients with Covid-19 also showed distinctive vascular features, consisting of severe endothelial injury associated with the presence of intracellular virus and disrupted cell membranes. Histologic analysis of pulmonary vessels in patients with Covid-19 showed widespread thrombosis with microangiopathy. Alveolar capillary microthrombi were 9 times as prevalent in patients with Covid-19 as in patients with influenza (P<0.001). In lungs from patients with Covid-19, the amount of new vessel growth - predominantly through a mechanism of intussusceptive angiogenesis - was 2.7 times as high as that in the lungs from patients with influenza (P<0.001). CONCLUSIONS: In our small series, vascular angiogenesis distinguished the pulmonary pathobiology of Covid-19 from that of equally severe influenza virus infection. The universality and clinical implications of our observations require further research to define. (Funded by the National Institutes of Health and others.).

A multicenter, randomized controlled clinical trial evaluating the effects of a novel autologous heterogeneous skin construct in the treatment of Wagner one diabetic foot ulcers: Final analysis.

A novel autologous heterogeneous skin construct (AHSC) was previously shown to be effective versus standard of care (SOC) treatment in facilitating complete wound healing of Wagner 1 diabetic foot ulcers in an interim analysis of 50 patients previously published. We now report the final analysis of 100 patients (50 per group), which further supports the interim analysis findings. Forty-five subjects in the AHSC treatment group received only one application of the autologous heterogeneous skin construct, and five received two applications. For the primary endpoint at 12 weeks, there were significantly more diabetic wounds closed in the AHSC treatment group (35/50, 70%) than in the SOC control group (17/50, 34%) (p = 0.00032). A significant difference in percentage area reduction between groups was also demonstrated over 8 weeks (p = 0.009). Forty-nine subjects experienced 148 adverse events: 66 occurred in 21 subjects (42%) in the AHSC treatment group versus 82 in 28 SOC control group subjects (56.0%). Eight subjects were withdrawn due to serious adverse events. Autologous heterogeneous skin construct was shown to be an effective adjunctive therapy for healing Wagner 1 diabetic foot ulcers.

Improved healing of chronic diabetic foot wounds in a prospective randomised controlled multi-centre clinical trial with a microvascular tissue allograft.

This study assesses the impact of a processed microvascular tissue (PMVT) allograft on wound closure and healing in a prospective, single-blinded, multi-centre, randomised controlled clinical trial of 100 subjects with Wagner Grade 1 and 2 chronic neuropathic diabetic foot ulcerations. In addition to standard wound care, including standardised offloading, the treatment arm received PMVT while the control arm received a collagen alginate dressing. The primary endpoint was complete wound closure at 12 weeks. Secondary endpoints assessed on all subjects were percent wound area reduction, time to healing, and local neuropathy. Novel exploratory sub-studies were conducted for wound area perfusion and changes in regional neuropathy. Weekly application of PMVT resulted in increased complete wound closure at 12 weeks (74% vs 38%; P = .0003), greater percent wound area reduction from weeks four through 12 (76% vs 24%; P = .009), decreased time to healing (54 days vs 64 days; P = .009), and improved local neuropathy (118% vs 11%; P = .028) compared with the control arm. Enhanced perfusion and improved regional neuropathy were demonstrated in the sub-studies. In conclusion, this study demonstrated increased complete healing with PMVT and supports its use in treating non-healing DFUs. The observed benefit of PMVT on the exploratory regional neuropathy and perfusion endpoints warrants further study.

A multicentre, randomised controlled clinical trial evaluating the effects of a novel autologous, heterogeneous skin construct in the treatment of Wagner one diabetic foot ulcers: Interim analysis.

We desired to carefully evaluate a novel autologous heterogeneous skin construct in a prospective randomised clinical trial comparing this to a standard-of-care treatment in diabetic foot ulcers (DFUs). This study reports the interim analysis after the first half of the subjects have been analysed. Fifty patients (25 per group) with Wagner 1 ulcers were enrolled at 13 wound centres in the United States. Twenty-three subjects underwent the autologous heterogeneous skin construct harvest and application procedure once; two subjects required two applications due to loss of the first application. The primary endpoint was the proportion of wounds closed at 12 weeks. There were significantly more wounds closed in the treatment group (18/25; 72%) vs controls (8/25; 32%) at 12 weeks. The treatment group achieved significantly greater percent area reduction compared to the control group at every prespecified timepoint of 4, 6, 8, and 12 weeks. Thirty-eight adverse events occurred in 11 subjects (44%) in the treatment group vs 48 in 14 controls (56%), 6 of which required study removal. In the treatment group, there were no serious adverse events related to the index ulcer. Two adverse events (index ulcer cellulitis and bleeding) were possibly related to the autologous heterogeneous skin construct. Data from this planned interim analysis support that application of autologous heterogeneous skin construct may be potentially effective therapy for DFUs and provide supportive data to complete the planned study.

Complete wound closure following a single topical application of a novel autologous homologous skin construct: first evaluation in an open-label, single-arm feasibility study in diabetic foot ulcers.

Diabetic foot ulcers (DFUs) are a growing burden on patients and health care systems that often require multiple treatments of both conventional and advanced modalities to achieve complete wound closure. A novel autologous homologous skin construct (AHSC) has been developed to treat cutaneous defects with a single topical application, by leveraging the endogenous repair capabilities of the patient's healthy skin. The AHSC's ability to close DFUs with a single treatment was evaluated in an open-label, single-arm feasibility study. Eleven patients with DFUs extending up to tendon, bone, or capsule received a single topical application of AHSC. Closure was documented weekly with high-resolution digital photography and wound planimetry. All 11 DFUs demonstrated successful graft take. Ten DFUs closed within 8 weeks. The median time-to-complete closure was 25 days. The mean percent area reduction for all 11 wounds at 4 weeks was 83%. There were no adverse events related to the AHSC treatment site. This pilot study demonstrated AHSC may be a viable single application topical intervention for DFUs and warrants investigation in larger, controlled studies.

Defining complete wound closure: Closing the gap in clinical trials and practice.

We investigate how wound closure is determined in recent randomized controlled wound trials and real-world studies, identify solutions to the current limitations of wound assessment, and propose a standard methodology to define and assess wound healing in research. We searched PubMed for randomized clinical trials using the terms "complete wound closure" and "wound healing rate" and for real-world studies using the terms "real-world wound healing," "real-world wound data," and "wound registries" dating from March 2010 through March 2018. We selected studies that had "complete wound closure" or "healed wound" as an endpoint. Sixty-five trial articles and 10 real-world articles met our criteria, from which we extracted the wound type studied, definition of healed wound used, wound assessment method, the number of weeks assessed, the number of wounds, and the percent of healed wounds in the study group(s) and control group. There were 7,194 trial wounds included. The most common definition of healing used by 26 studies (40.6%) was complete/full/100% (re)epithelialization or closure without discharge, drainage/scab, and/or dressing. Fifty-two studies (81.2%) used blinded wound assessment, and at least 10 studies (15.6%) used blinded adjudication. The real-world studies analyzed more than 901,396 wounds. Only three studies (33.3%) defined a healed/closed wound, two of which used "complete epithelialization." Eight studies (88.9%) did not define the wound assessment method; none indicated a blinded assessment. We support the Food and Drug Administration definition: 100% reepithelialization of the wound surface with no discernable exudate and without drainage or dressing, confirmed at two visits 2 weeks apart, and we recommend blinded adjudication for wound assessment. The widespread adoption of a standard wound healing definition and assessment method in wound care research would allow for stronger comparisons of treatment effects across studies to improve the evidence base and strengthen the treatment decision-making process in clinical practice.

In vivo expansion and regeneration of full-thickness functional skin with an autologous homologous skin construct: Clinical proof of concept for chronic wound healing.

A new cell-tissue technology uses a patient's skin to create an in vivo expanding and self-organising full-thickness skin autograft derived from potent cutaneous appendages. This autologous homologous skin construct (AHSC) is manufactured from a small full-thickness skin harvest obtained from an uninjured area of the patient. All the harvested tissue is incorporated into the AHSC including the endogenous regenerative cellular populations responsible for skin maintenance and repair, which are activated during the manufacturing process. Without any exogenous supplementation or culturing, the AHSC is swiftly returned to the patient's wound bed, where it expands and closes the defect from the inside out with full-thickness fully functional skin. AHSC was applied to a greater than two-year old large (200 cm2 ) chronic wound refractory to multiple failed split-thickness skin grafts. Complete epithelial coverage was achieved in 8 weeks, and complete wound coverage with full-thickness functional skin occurred in 12 weeks. At 6-month follow-up, the wound remained covered with full-thickness skin, grossly equivalent to surrounding native skin qualitatively and quantitatively equivalent across multiple functions and characteristics, including sensation, hair follicle morphology, bio-impedance and composition, pigment regeneration, and gland production.

An aseptically processed, acellular, reticular, allogenic human dermis improves healing in diabetic foot ulcers: A prospective, randomised, controlled, multicentre follow-up trial.

Aseptically processed human reticular acellular dermal matrix (HR-ADM) has been previously shown to improve wound closure in 40 diabetic patients with non-healing foot ulcers. The study was extended to 40 additional patients (80 in total) to validate and extend the original findings. The entire cohort of 80 patients underwent appropriate offloading and standard of care (SOC) during a 2-week screening period and, after meeting eligibility criteria, were randomised to receive weekly applications of HR-ADM plus SOC or SOC alone for up to 12 weeks. The primary outcome was the proportion of wounds closed at 6 weeks. Sixty-eight percent (27/40) in the HR-ADM group were completely healed at 6 weeks compared with 15% (6/40) in the SOC group. The proportions of wounds healed at 12 weeks were 80% (34/40) and 30% (12/40), respectively. The mean time to heal within 12 weeks was 38 days for the HR-ADM group and 72 days for the SOC group. There was no incidence of increased adverse or serious adverse events between groups or any graft-related adverse events. The mean and median HR-ADM product costs at 12 weeks were $1200 and $680, respectively. HR-ADM is clinically superior to SOC, is cost effective relative to other comparable treatment modalities, and is an efficacious treatment for chronic non-healing diabetic foot ulcers.

Identification and content validation of wound therapy clinical endpoints relevant to clinical practice and patient values for FDA approval. Part 1. Survey of the wound care community.

Wounds that exhibit delayed healing add extraordinary clinical, economic, and personal burdens to patients, as well as to increasing financial costs to health systems. New interventions designed to ease such burdens for patients with cancer, renal, or ophthalmologic conditions are often cleared for approval by the U.S. Food and Drug Administration (FDA) using multiple endpoints but the requirement of complete healing as a primary endpoint for wound products impedes FDA clearance of interventions that can provide other clinical or patient-centered benefits for persons with wounds. A multidisciplinary group of wound experts undertook an initiative, in collaboration with the FDA, to identify and content validate supporting FDA criteria for qualifying wound endpoints relevant to clinical practice (CP) and patient-centered outcomes (PCO) as primary outcomes in clinical trials. As part of the initiative, a research study was conducted involving 628 multidisciplinary expert wound clinicians and researchers from 4 different groups: the interdisciplinary core advisory team; attendees of the Spring 2015 Symposium on Advanced Wound Care (SAWC); clinicians employed by a national network of specialty clinics focused on comprehensive wound care; and Association for the Advancement of Wound Care (AAWC) and Wound Healing Society (WHS) members who had not previously completed the survey. The online survey assessed 28 literature-based wound care endpoints for their relevance and importance to clinical practice and clinical research. Fifteen of the endpoints were evaluated for their relevance to improving quality of life. Twenty-two endpoints had content validity indexes (CVI) ≥ 0.75, and 15 were selected as meriting potential inclusion as additional endpoints for FDA approval of future wound care interventions. This study represents an important first step in identifying and validating new measurable wound care endpoints for clinical research and practice and for regulatory evaluation.

Vascular assessment of wound healing: a clinical review.

Although macrovascular screening of patients with chronic wounds, particularly in the lower extremities, is accepted as part of clinical practice guidelines, microvascular investigation is less commonly used for a variety of reasons. This can be an issue because most patients with macrovascular disease also develop concomitant microvascular dysfunction. Part of the reason for less comprehensive microvascular screening has been the lack of suitable imaging techniques that can quantify microvascular dysfunction in connection with non-healing chronic wounds. This is changing with the introduction of fluorescence microangiography. The objective of this review is to examine macro- and microvascular disease, the strengths and limitations of the approaches used and to highlight the importance of microvascular angiography in the context of wound healing.