Modified poly(L-lysine)-based structures as novel antimicrobials for diabetic foot infections, an in-vitro study

Background: Wound infections occur as sequelae to skin trauma and cause significant hospitalizations, morbidity and mortality. Skin traumas arise more frequently in those with diabetes or cardiovascular disease and in these settings, may be chronic with poorer outcomes including lower limb amputation. Treatment of chronic wound infection is challenging due to antibiotic resistance and biofilm formation by bacteria including S. aureus and P. aeruginosa, which are among the most frequent causative pathogens. Managing these challenging infections requires new molecules and modalities. Methods: We evaluated antimicrobial and anti-biofilm activity of star-shaped poly(L-lysine) (PLL) polymers against S. aureus and P. aeruginosa strains and clinical isolates recovered from wounds including diabetic foot wounds (DFW) in a Dublin Hospital in 2019. A star-shaped PLL polypeptide series, specifically G2(8)PLL20, G3(16)PLL10, G4(32)PLL5 with variation in polypeptide chain length and arm-multiplicity, were compared to a linear peptide, PLL160 with equivalent number of lysine residues. Results: All PLLs, including the linear polypeptide, were bactericidal at 1mM against S. aureus 25923 and P. aeruginosa PAO1, with log reduction in colony forming units/ml between 2.7-3.6. PLL160 demonstrated similar killing potency against 20 S. aureus and five P. aeruginosa clinical isolates from DFW, mean log reductions: 3.04 ± 0.16 and 3.96 ± 0.82 respectively after 1 hour incubation. Potent anti-biofilm activity was demonstrated against S. aureus 25923 but for clinical isolates, low to moderate loss of biofilm viability was shown using PLL160 and G3(16)PLL10 at 50 mM (S. aureus) and 200 mM (P. aeruginosa) with high inter-isolate variability. In the star-shaped architecture, antimicrobial activity was retained with incorporation of 5-mer hydrophobic amino-acid modifications to the arms of the polypeptides (series G3(16)PLL20-coPLT5, G3(16)PLL20-coPLI5, G3(16)PLL20-coPLP5). Conclusion: These polypeptides offer structural flexibility for clinical applications and have potential for further development, particularly in the setting of diabetic foot and other chronic wound infections.

The chronic wound virome: phage diversity and associations with wounds and healing outcomes

Two leading impediments to chronic wound healing are polymicrobial infection and biofilm formation. Recent studies have characterized the bacterial fraction of these microbiomes and have begun to elucidate compositional correlations to healing outcomes. However, the factors that drive compositional shifts are still being uncovered. The virome may play an important role in shaping bacterial community structure and function. Previous work on the skin virome determined that it was dominated by bacteriophages, viruses that infect bacteria. To characterize the virome, we enrolled 20 chronic wound patients presenting at an outpatient wound care clinic in a microbiome survey, collecting swab samples from healthy skin and chronic wounds before and after a single, sharp debridement procedure. We investigated the virome using a virus-like particle enrichment procedure, shotgun metagenomic sequencing, and a k-mer-based, reference-dependent taxonomic classification method. Taxonomic composition, diversity, and associations to covariates are presented. We find that the wound virome is highly diverse, with many phages targeting known pathogens, and may influence bacterial community composition and functionality in ways that impact healing outcomes.

Dissolving microneedle-encapsulated drug-loaded nanoparticles and recombinant humanized collagen type III for the treatment of chronic wound via anti-inflammation and enhanced cell proliferation and angiogenesis

The first recombinant humanized collagen type III (rhCol III) and naproxen (Nap) loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles incorporated hyaluronic acid (HA) microneedle (MN) was fabricated for diabetic chronic wounds therapy.

Molecular Mechanism of Extractum Liquidum Drug Loading Materials on Promoting Chronic Wound Tissue Repair Through Phosphatidylinositol 3 Kinase/Protein Kinase B/Hypoxia Induction Factor 1α Signal Pathway

To solve the shortcomings of traditional Zeji extractum liquidum (traditional Chinese medicine used for wound healing), and to explore the effect of Zeji Etractum Lquidum (ZLE) Nano Materials (ZLENM) on chronic wound (CW) healing and its molecular mechanism. 30 SD rats were divided into 3 groups in random: control group (Ctrl group), model group (CW group), and treatment group (ZLENM group). The results of wound healing rate showed that, in contrast with the CW, the healing rate of back wounds in the ZLENM group was greatly increased on the 7th and 14th days (P < 0.05). In contrast with the Ctrl, the rats in the CW and the ZLENM groups had greatly increased CD31 positive staining on the 7th and 14th days (P < 0.05), and the CW was lower than the ZLENM group (P < 0.05). In contrast with the 7th day, the MVD in the CW and the ZLENM groups was greatly reduced on the 14th day (P < 0.05). Western blot analysis of the expression of related signal molecules showed that the expressions of P-Akt, P-PI3K, HIF-1α, and VEGFR2 protein in the wounds in the CW and ZLENM groups were greatly increased in contrast with the Ctrl (P < 0.05), and CW was lower than ZLENM group (P < 0.05). In conclusion, ZLENM can promote wound healing and increase the number of wound angiogenesis in CW rats. The mechanism is related to the activation of phosphatidylinositol 3 kinase/protein kinase B/hypoxia induction factor 1α (PI3K/AKT/HIF-1α) signaling pathway.

Infection Probability Index: Implementation of an Automated Chronic Wound Infection Marker

The number of people suffering from chronic wounds is increasing due to demographic changes and the global epidemics of obesity and diabetes. Innovative imaging techniques within the field of chronic wound diagnostics are required to improve wound care by predicting and detecting wound infections to accelerate the application of treatments. For this reason, the infection probability index (IPI) is introduced as a novel infection marker based on thermal wound imaging. To improve usability, the IPI was implemented to automate scoring. Visual and thermal image pairs of 60 wounds were acquired to test the implemented algorithms on clinical data. The proposed process consists of (1) determining various parameters of the IPI based on medical hypotheses, (2) acquiring data, (3) extracting camera distortions using camera calibration, and (4) preprocessing and (5) automating segmentation of the wound to calculate (6) the IPI. Wound segmentation is reviewed by user input, whereas the segmented area can be refined manually. Furthermore, in addition to proof of concept, IPIs’ correlation with C-reactive protein (CRP) levels as a clinical infection marker was evaluated. Based on average CRP levels, the patients were clustered into two groups, on the basis of the separation value of an averaged CRP level of 100. We calculated the IPIs of the 60 wound images based on automated wound segmentation. Average runtime was less than a minute. In the group with lower average CRP, a correlation between IPI and CRP was evident.

Extracellular Nucleotides Affect the Proangiogenic Behavior of Fibroblasts, Keratinocytes, and Endothelial Cells

Chronic wound healing is currently a severe problem due to its incidence and associated complications. Intensive research is underway on substances that retain their biological activity in the wound microenvironment and stimulate the formation of new blood vessels critical for tissue regeneration. This group includes synthetic compounds with proangiogenic activity. Previously, we identified phosphorothioate analogs of nucleoside 5′-O-monophosphates as multifunctional ligands of P2Y6 and P2Y14 receptors. The effects of a series of unmodified and phosphorothioate nucleotide analogs on the secretion of VEGF from keratinocytes and fibroblasts, as well as their influence on the viability and proliferation of keratinocytes, fibroblasts, and endothelial cells were analyzed. In addition, the expression profiles of genes encoding nucleotide receptors in tested cell models were also investigated. In this study, we defined thymidine 5′-O-monophosphorothioate (TMPS) as a positive regulator of angiogenesis. Preliminary analyses confirmed the proangiogenic potency of TMPS in vivo.

Mobile Health App for Chronic Wound Management (Preprint)

BACKGROUND Chronic ulcers, and especially ulcers affecting the lower extremities and their protracted evolution, are a health problem with significant socio-economic repercussions. The patient's quality of life often deteriorates, leading to serious personal problems for the patient and, in turn, major care challenges for healthcare professionals. Our study proposes a new approach for assisting wound assessment and criticality with an integrated framework based on a Mobile App and a Cloud platform, supporting the practitioner and optimising organisational processes. This framework, called Clinicgram, uses a decision-making support method, such as morphological analysis of wounds and artificial intelligence algorithms for feature classification and a system for matching similar cases via an easily accessible and user-friendly mobile app, and assesses the clinician to choose the best treatment. OBJECTIVE The main objective of this work is to evaluate the impact of the incorporation of Clinicgram, a mobile App and a Cloud platform with Artificial Intelligence algorithms to help the clinician as a decision support system to assess and evaluate correct treatments. Second objective evaluates how the professional can benefit from this technology into the real clinical practice, how it impacts patient care and how the organisation’s resources can be optimised. METHODS Clinicgram application and framework is a non-radiological clinical imaging management tool that is incorporated into clinical practice. The tool will also enable the execution of the different algorithms intended for assessment in this study. With the use of computer vision and supervised learning techniques, different algorithms are implemented to simplify a practitioner's task of assessment and anomaly spotting in clinical cases. Determining the area of interest of the case automatically and using it to assess different wound characteristics such as area calculation and tissue classification, and detecting different signs of infection. An observational and an objective study have been carried out that will allow obtaining clear indicators of the level of usability in clinical practice. RESULTS A total of 2,750 wound pictures were taken by 10 nurses for analysis during the study from January 2018 to November 2021. Objective results have been obtained from the use and management of the application, important feedback from professionals with a score of 5.55 out of 7 according to the mHealth App Usability Questionnaire. It has also been possible to collect the most present type of wound according to Resvech 2.0 of between 6 and 16 points of severity, and highlight the collection of images of between 0 and 16 cm2 of area 88%, with involvement of subcutaneous tissue 53.21%, with the presence of granulated tissue 59.16% and necrotic 30.29% and with a wet wound bed 61.54%. The usage of app to upload samples increase from 31 to 110 samples per month from 2018 to 2021. CONCLUSIONS Our real-world assessment demonstrates the effectiveness and reliability of the wound assessment system, increasing professional efficiency, reducing data collection time during the visit and optimising costs-effectivity in the healthcare organisation by reducing treatment variability. Also, the comfort of the professional and patient. Incorporating a tool such as Clinicgram into the chronic wound assessment and monitoring process adds value, reduction of errors and improves both the clinical practice process time, while also improving decision-making by the professional and consequently having a positive impact on the patient's wound healing process.

A Retrospective Analysis of Clinical Use and Outcomes Using Viable Placental Membrane Allografts in Chronic Wounds

Introduction. Viable placental membrane (vPM) has been shown to decrease time to healing, adverse wound events, and wound-related infections. Wound research exclusion criteria commonly exclude wound types other than diabetic foot ulcers and venous leg ulcers (VLUs), comorbidities including peripheral arterial disease (PAD) and uncontrolled diabetes mellitus (DM), and wounds with exposed bone or tendon. Objective. This retrospective research study evaluated the clinical use and outcomes of the vPM with living mesenchymal stem cells used in chronic wound management in the community hospital outpatient department setting with the goal of comparing real-world use and outcomes of the product with use and outcomes described in the chronic wound literature. Materials and Methods. A retrospective analysis on vPM treatments at a Wisconsin academic health system’s community hospitals. Participants included all patients who received vPM therapy between July 1, 2016, and August 21, 2019. Results. A total of 89 patients received vPM treatment during the study period (mean age, 70 years; 69% male [n = 61], 31% female [n = 28]). Wound types were 54% diabetic or neuropathic foot ulcers (n = 48), 17% VLUs (n = 15), 7% pressure injuries (n = 6), and 22% atypical wounds (n = 20). The average wound duration prior to vPM initiation was 104 days. Average wound size at presentation was 6.9 cm2. Of study participants 54% had PAD (n = 48), 63% had DM (n = 56), 33.7% had DM and PAD (n = 30), and 17% had exposed bone or tendon (n = 15). Average adjusted time to healing after initiation of vPM was 81.2 days. The percentage of wounds healed 12 weeks after initiation of vPM treatment was 57%. Conclusions. Effectiveness of vPM observed in controlled trials also was observed in this real-world study on vPM for multiple wound types, patients with comorbidities including PAD and uncontrolled DM, and wounds with exposed bone or tendon. Results of this study were not statistically different from those reported in the literature. More randomized controlled trials are needed to explore the efficacy of vPM on patient presentations common to wound healing centers.