Myeloperoxidase-responsive materials for infection detection based on immobilized aminomethoxyphenol

Designing and characterization of curcumin-loaded nanotechnological dressings: A promising platform for skin burn treatment

Burns affect the skin and appendages, impair their function, and become favorable regions for bacterial infections. Owing to time-consuming and costly treatments, burns have been considered a public health problem. The limitations of the treatments used for burns have motivated the search for more efficient alternatives. Curcumin has several potential properties such as anti-inflammatory, healing, and antimicrobial activities. However, this compound is unstable and has low bioavailability. Therefore, nanotechnology could offer a solution for its application. This study aimed to develop and characterize dressings (or gauzes) impregnated with curcumin nanoemulsions that were prepared using two different techniques as a promising platform for skin burn treatment. In addition, the effect of cationization on curcumin release from the gauze was evaluated. Nanoemulsions were successfully prepared using two methods, ultrasound and a high-pressure homogenizer, with sizes of 135 nm and 144.55 nm, respectively. These nanoemulsions exhibited a low polydispersity index, adequate zeta potential, high encapsulation efficiency, and stability for up to 120 d. In vitro assays demonstrated a controlled release of curcumin between 2 and 240 h. No cytotoxicity was observed at concentrations of curcumin up to 75 µg/mL, and cell proliferation was observed. The incorporation of nanoemulsions in the gauze was successfully achieved, and the evaluation of curcumin release showed a faster release from cationized gauzes, whereas the non-cationized gauze promoted a more constant release.

Biomaterials releasing drug responsively to promote wound healing via regulation of pathological microenvironment

Wound healing is characterized by complex, orchestrated, spatiotemporal dynamic processes. Recent findings demonstrated suitable local microenvironments were necessities for wound healing. Wound microenvironments include various biological, biochemical and physical factors, which are produced and regulated by endogenous biomediators, exogenous drugs, and external environment. Successful drug delivery to wound is complicated, and need to overcome the destroyed blood supply, persistent inflammation and enzymes, spatiotemporal requirements of special supplements, and easy deactivation of drugs. Triggered by various factors from wound microenvironment itself or external elements, stimuli-responsive biomaterials have tremendous advantages of precise drug delivery and release. Here, we discuss recent advances of stimuli-responsive biomaterials to regulate local microenvironments during wound healing, emphasizing on the design and application of different biomaterials which respond to wound biological/biochemical microenvironments (ROS, pH, enzymes, glucose and glutathione), physical microenvironments (mechanical force, temperature, light, ultrasound, magnetic and electric field), and the combination modes. Moreover, several novel promising drug carriers (microbiota, metal-organic frameworks and microneedles) are also discussed.

A Host-Directed Approach to the Detection of Infection in Hard-to-Heal Wounds

Wound infection is traditionally defined primarily by visual clinical signs, and secondarily by microbiological analysis of wound samples. However, these approaches have serious limitations in determining wound infection status, particularly in early phases or complex, chronic, hard-to-heal wounds. Early or predictive patient-derived biomarkers of wound infection would enable more timely and appropriate intervention. The observation that immune activation is one of the earliest responses to pathogen activity suggests that immune markers may indicate wound infection earlier and more reliably than by investigating potential pathogens themselves. One of the earliest immune responses is that of the innate immune cells (neutrophils) that are recruited to sites of infection by signals associated with cell damage. During acute infection, the neutrophils produce oxygen radicals and enzymes that either directly or indirectly destroy invading pathogens. These granular enzymes vary with cell type but include elastase, myeloperoxidase, lysozyme, and cathepsin G. Various clinical studies have demonstrated that collectively, these enzymes, are sensitive and reliable markers of both early-onset phases and established infections. The detection of innate immune cell enzymes in hard-to-heal wounds at point of care offers a new, simple, and effective approach to determining wound infection status and may offer significant advantages over uncertainties associated with clinical judgement, and the questionable value of wound microbiology. Additionally, by facilitating the detection of early wound infection, prompt, local wound hygiene interventions will likely enhance infection resolution and wound healing, reduce the requirement for systemic antibiotic therapy, and support antimicrobial stewardship initiatives in wound care.

Advanced Wound Diagnostics: Toward Transforming Wound Care into Precision Medicine

Significance: Nonhealing wounds are an ever-growing global pandemic, with mortality rates and management costs exceeding many common cancers. Although our understanding of the molecular and cellular factors driving wound healing continues to grow, standards for diagnosing and evaluating wounds remain largely subjective and experiential, whereas therapeutic strategies fail to consistently achieve closure and clinicians are challenged to deliver individualized care protocols. There is a need to apply precision medicine practices to wound care by developing evidence-based approaches, which are predictive, prescriptive, and personalized. Recent Advances: Recent developments in "advanced" wound diagnostics, namely biomarkers (proteases, acute phase reactants, volatile emissions, and more) and imaging systems (ultrasound, autofluorescence, spectral imaging, and optical coherence tomography), have begun to revolutionize our understanding of the molecular wound landscape and usher in a modern age of therapeutic strategies. Herein, biomarkers and imaging systems with the greatest evidence to support their potential clinical utility are reviewed. Critical Issues: Although many potential biomarkers have been identified and several imaging systems have been or are being developed, more high-quality randomized controlled trials are necessary to elucidate the currently questionable role that these tools are playing in altering healing dynamics or predicting wound closure within the clinical setting. Future Directions: The literature supports the need for the development of effective point-of-care wound assessment tools, such as a platform diagnostic array that is capable of measuring multiple biomarkers at once. These, along with advances in telemedicine, synthetic biology, and "smart" wearables, will pave the way for the transformation of wound care into a precision medicine. Clinical Trial Registration number: NCT03148977.

Wound infection: A review of qualitative and quantitative assessment modalities

Surgical site infections (SSI) and chronic wounds represent a burden to patients and the health care system. One in 24 surgical patients will develop an SSI, making SSI the most common nosocomial infection in the USA. Early detection and monitoring of wound infection are critical for timely healing and return to normal function. However, the mainstay of wound infection diagnostic entails subjective clinical examination and semi-quantitative, invasive microbiological tests. In this review, we present current wound infection assessment modalities in the clinical and translational fields. There is a need for a point-of-care assessment tool that provides fast, accurate, and quantitative information on wound status, with minimal to no contact with the patient. In the next ten years, the evolution of wound diagnostic tools reported here may allow medical providers to optimize patient care while minimizing patient discomfort.

Molecular Changes in Diabetic Wound Healing following Administration of Vitamin D and Ginger Supplements: Biochemical and Molecular Experimental Study

BACKGROUND

Circulating micro-RNAs are differentially expressed in various tissues and could be considered as potential regulatory biomarkers for T2DM and related complications, such as chronic wounds.

AIM

In the current study, we investigated whether ginger extract enriched with [6]-gingerol-fractions either alone or in combination with vitamin D accelerates diabetic wound healing and explores underlying molecular changes in the expression of miRNA and their predicted role in diabetic wound healing.

METHODS

Diabetic wounded mice were treated with [6]-gingerol-fractions (GF) (25 mg/kg of body weight) either alone or in combination with vitamin D (100 ng/kg per day) for two weeks. Circulating miRNA profile, fibrogenesis markers, hydroxyproline (HPX), fibronectin (FN), and collagen deposition, diabetic control variables, FBS, HbA1c, C-peptide, and insulin, and wound closure rate and histomorphometric analyses were, respectively, measured at days 3, 6, 9, and 15 by RT-PCR and immunoassay analysis.

RESULTS

Treatment of diabetic wounds with GF and vitamin D showed significant improvement in wound healing as measured by higher expression levels of HPX, FN, collagen, accelerated wound closure, complete epithelialization, and scar formation in short periods (11-13 days, (P < 0.01). On a molecular level, three circulating miRNAs, miR-155, miR-146a, and miR-15a, were identified in diabetic and nondiabetic skin wounds by PCR analysis. Lower expression in miR-155 levels and higher expression of miR-146a and miR-15a levels were observed in diabetic skin wounds following treatment with gingerols fractions and vitamin D for 15 days. The data showed that miRNAs, miR-146a, miR-155, and miR-15a, correlated positively with the expression levels of HPX, FN, and collagen and negatively with FBS, HbA1c, C-peptide, and insulin in diabetic wounds following treatment with GF and /or vitamin D, respectively.

CONCLUSION

Treatment with gingerols fractions (GF) and vitamin D for two weeks significantly improves delayed diabetic wound healing. The data showed that vitamin D and gingerol activate vascularization, fibrin deposition (HPX, FN, and collagen), and myofibroblasts in such manner to synthesize new tissues and help in the scar formation. Accordingly, three miRNAs, miR-155, miR-146a, and miR-15, as molecular targets, were identified and significantly evaluated in wound healing process. It showed significant association with fibrin deposition, vascularization, and reepithelialization process following treatment with GF and vitamin D. It proposed having anti-inflammatory action and promoting new tissue formation via vascularization process during the wound healing. Therefore, it is very interesting to consider miRNAs as molecular targets for evaluating the efficiency of nondrug therapy in the regulation of wound healing process.

Evaluation of the Biological Effects of Lyophilized Hydrophilic Extract of Rhus coriaria on Myeloperoxidase (MPO) Activity, Wound Healing, and Microbial Infections of Skin Wound Tissues

Impaired wound healing was mainly associated with severe microbial infections which significantly affect diagnostic and therapeutic strategies. Thus, in this study, the potential wound healing activity, anti-inflammatory, and antimicrobial activity of an aqueous extract of Rhus coriaria extract (AERc) were evaluated by wound contraction, scar formation, period of epithelization, MPO enzyme activity, collagenase-2 (MMP-8), hydroxyproline (HPX), and collagen deposition as markers of wound healing at different days of postwound. Phytoconstituents, microbial activity, and fibrogenic markers were screened by HPLC, disc-diffusion, and colorimetric assays. The animals were treated with Rhus coriaria extract (AERc) concentrations at doses of 5 mg.kg⁻¹and 10 mg.kg⁻¹, respectively. On days 6 and 9, the AERc-treated animals at doses of 5 mg.mL⁻¹ and 10 mg.mL⁻¹ exhibited a significant reduction in the wound area, increased deposition of collagen, HPX, and reduction in MMP-8, and MPO enzyme activity when compared with controls. Scar formation and epithelization were completed in 10 days compared to controls. In addition, in wounds infected separately with Staph. aureus or P. aeruginosa, the AERc extract significantly improved wound contraction, deposition of collagen, and HPx and reduced MMP-8 and MPO concentrations, with complete epithelization of wounds in 10-13 days compared to the saline-treated group. Hydrolyzable tannins, gallic acid, quercetin, and myricetin were the most common active components of AERc. In vitro, the AERc and its components were effective against a set of microbes especially Staph. aureus, P. aeruginosa, and Staph. aureus (MRSA). In conclusion, the results showed that antimicrobial, anti-inflammatory, and antioxidant activity of Rhus coriaria extract suggested its importance as a target for formulation of novel drugs against many microbial infections with minimal side effects and could play a good potential role in accelerating wound healing activity via promoting myofibroblast activity, increase of hydroxyproline and collagen deposition, and regulation of MMP-8 and MPO enzyme activities.

Design of a chromogenic substrate for elastase based on split GFP system-Proof of concept for colour switch sensors

Recent studies have demonstrated that human neutrophil elastase (HNE) can be used as marker for inflammation/infection of chronic wounds since it was found to be present in high concentration in exudate collected from chronic wounds. Biosensors used in wound care benefit from a chromogenic signalling due to the readiness of signal interpretation, but the most common use faint yellow chromogenic molecules such as p-nitroaniline (pNa). In addition, if to be converted into smart dressings, the colour of the detection system should not be masked by the exudate's colour. In this work, we designed a chromogenic substrate for HNE aiming to be incorporated in a smart dressing as a colour switch sensor. The substrate was developed using the GFP-like chromoprotein ultramarine (UM), following the split GFP technology. The cleavage sequence for HNE (Ala-Ala-Pro-Val) was embedded into the sensing moiety of the substrate corresponding to the 11th β-sheet. In the presence of HNE, the 11th β-sheet is able to interact to the signalling moiety composed of the β1-β10 incomplete barrel, allowing the re-establishment of the chromophore environment and, hence, the colour production. Structural homology and molecular dynamics simulations were conducted to aid on the disclosure of the structural changes that are the base of the mechanism of action of this HNE switch substrate. Our findings explore the possible application of GFP-like chromogenic sensors in point-of-care devices for the evaluation of the wounds status, representing a major step in the medical field.

Assessment of histopathology of wounds based on protein distribution detected by wound blotting

Background:

Shortening the duration of healing based on an accurate assessment is important in pressure ulcer management. This study focused on the peroxidase and alkaline phosphatase activity detected by wound blotting, a non-invasive method of collecting wound exudate, to establish a non-invasive and point-of-care assessment method for analyzing the histopathology of wounds using an animal model.

Methods:

Wounds were created on the dorsal skin of rats. Peroxidase and alkaline phosphatase activities in the wound exudate were detected by wound blotting on post-wounding days 1, 4, 7, and 10. Wound tissue was collected on the same sampling days. Peroxidase and alkaline phosphatase activity within the tissue and myeloperoxidase were visualized. Two types of peroxidase activities were detected by wound blotting: ring and non-ring signals. The histopathological features were compared between wounds with ring and non-ring signals.

Results:

The wounds with ring signals showed a high level of peroxidase activity, and histological analysis demonstrated that the secreted or deviated peroxidase activity originated from myeloperoxidase, indicating a strong inflammation reaction within the tissue. The histopathology of wounds related to the alkaline phosphatase signals was not identified.

Conclusion:

The results suggested that ring signals indicated a strong inflammatory reaction and that they could be used to assess non-visible inflammation.