scholarly journals In Vitro Investigation of Thiol-Functionalized Cellulose Nanofibrils as a Chronic Wound Environment Modulator

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 249
Author(s):  
Anna Blasi-Romero ◽  
Carlos Palo-Nieto ◽  
Corine Sandström ◽  
Jonas Lindh ◽  
Maria Strømme ◽  
...  
Keyword(s):  
Protease Activity ◽  
Chronic Wounds ◽  
Chronic Wound ◽  
Cellulose Nanofibrils ◽  
Dermal Fibroblasts ◽  
Wound Dressings ◽  
Thiol Groups ◽  
The Stability ◽  
Over Time

There is currently a huge need for new, improved therapeutic approaches for the treatment of chronic wounds. One promising strategy is to develop wound dressings capable of modulating the chronic wound environment (e.g., by controlling the high levels of reactive oxygen species (ROS) and proteases). Here, we selected the thiol-containing amino acid cysteine to endow wood-derived cellulose nanofibrils (CNF) with bioactivity toward the modulation of ROS levels and protease activity. Cysteine was covalently incorporated into CNF and the functionalized material, herein referred as cys-CNF, was characterized in terms of chemical structure, degree of substitution, radical scavenging capacity, and inhibition of protease activity. The stability of the thiol groups was evaluated over time, and an in vitro cytotoxicity study with human dermal fibroblasts was performed to evaluate the safety profile of cys-CNF. Results showed that cys-CNF was able to efficiently control the activity of the metalloprotease collagenase and to inhibit the free radical DPPH (1,1-Diphenyl-2-picrylhydrazyl radical), activities that were correlated with the presence of free thiol groups on the nanofibers. The stability study showed that the reactivity of the thiol groups challenged the bioactivity over time. Nevertheless, preparing the material as an aerogel and storing it in an inert atmosphere were shown to be valid approaches to increase the stability of the thiol groups in cys-CNF. No signs of toxicity were observed on the dermal fibroblasts when exposed to cys-CNF (concentration range 0.1–0.5 mg/mL). The present work highlights cys-CNF as a promising novel material for the development of bioactive wound dressings for the treatment of chronic wounds.

Dermal Fibroblasts from Chronic Wounds Exhibit Paradoxically Enhanced Proliferative and Migratory Activities that May be Related to the Non-Canonical Wnt Signaling Pathway

2021 ◽  
Vol 39 ◽  
Author(s):  
Marta Vinas ◽  
◽  
Xiaofeng Lin ◽  
Susan MacLauchlan ◽  
Polly Carson ◽  
...  
Keyword(s):  
Chronic Wounds ◽  
Chronic Wound ◽  
Wnt Signaling Pathway ◽  
High Energy ◽  
Dermal Fibroblasts ◽  
Live Cell ◽  
Mrna Levels ◽  
Venous Leg Ulcer ◽  
Recurrence Rates

It is generally thought that dermal fibroblasts from chronic wounds are in a state of senescence, which contributes to the failure to heal. This assumption, based on limited experimental evidence, has led to the widespread use of therapeutic approaches focused on delivering new fibroblasts and/or increasing resident fibroblast activity to promote healing. In this study, we decided to re-visit the evidence for the relative inactivity of resident chronic wound fibroblasts. We therefore evaluated the proliferative and migratory activities of matching, patient-derived dermal fibroblasts from a chronic wound (wound dermal fibroblasts, or WDF), ipsilateral thigh newly created acute wound dermal fibroblasts (ADF, Day-3 after wounding the normal thigh skin), and ipsilateral thigh normal dermal skin fibroblasts (NDF). This approach was used in each of 10 consecutive non-selected individual patients with a venous leg ulcer, and allowed us to determine whether WDF are intrinsically less active than NDF and AWD. Cell migration and proliferation were quantified by a live-cell analysis system and MTT assay, respectively, in low (0.5%) or high (10%) levels of fetal bovine serum (FBS). In addition, the ability of patient-derived fibroblasts to modulate wound re-epithelialization in vivo was analyzed by transplantation in a mouse tail full-thickness wound model. Wnt5a mRNA, its ROR1 co-receptors, and ROR2 mRNA levels were determined by qRT-PCR. We report that WDF had increased -SMA and increased levels of Wnt5a. Moreover, using live-cell imaging in a scratch assay monolayer model, WDF showed baseline migratory activity similar to those of NDF and ADF, and such activity was not stimulated by FBS. WDF showed the same capacity to increase wound re-epithelialization as NDF and ADF. Together, these results suggest that WDF are not actually less "active" than NDF and ADF. This enhanced activity of chronic wound fibroblasts may lead to high energy requirements that contribute to a failure to heal. The findings may represent a new paradigm for wound chronicity, impaired healing, and high recurrence rates.

scholarly journals N-Acetyl-cysteine and Mechanisms Involved in Resolution of Chronic Wound Biofilm

2020 ◽  
Vol 2020 ◽  
pp. 1-16 ◽  
Author(s):  
Xin Li ◽  
Jane Kim ◽  
Jiabin Wu ◽  
Alaa’ I Ahamed ◽  
Yinsheng Wang ◽  
...  
Keyword(s):  
Cell Death ◽  
Bacterial Cell ◽  
Chronic Wounds ◽  
Chronic Wound ◽  
Diabetic Mouse ◽  
Bacterial Survival ◽  
Bacterial Cell Death ◽  
Carboxylic Groups ◽  
Acetyl Cysteine

Chronic wounds are a major global health problem with the presence of biofilm significantly contributing to wound chronicity. Current treatments are ineffective in resolving biofilm and simultaneously killing the bacteria; therefore, effective biofilm-resolving drugs are needed. We have previously shown that, together with α-tocopherol, N-acetyl-cysteine (NAC) significantly improves the healing of biofilm-containing chronic wounds, in a diabetic mouse model we developed, by causing disappearance of the bacteria and breakdown of the extracellular polymeric substance (EPS). We hypothesize that NAC creates a microenvironment that affects bacterial survival and EPS integrity. To test this hypothesis, we developed an in vitro biofilm system using microbiome taken directly from diabetic mouse chronic wounds. For these studies, we chose mice in which chronic wound microbiome was rich in Pseudomonas aeruginosa (97%). We show that NAC at concentrations with pH < pKa causes bacterial cell death and breakdown of EPS. When used before biofilm is formed, NAC leads to bacterial cell death whereas treatment after the biofilm is established NAC causes biofilm dismantling accompanied by bacterial cell death. Mechanistically, we show that NAC can penetrate the bacterial membrane, increase oxidative stress, and halt protein synthesis. We also show that low pH is important for the actions of NAC and that bacterial death occurs independently of the presence of biofilm. In addition, we show that both the acetyl and carboxylic groups play key roles in NAC functions. The results presented here provide insight into the mechanisms by which NAC dismantles biofilm and how it could be used to treat chronic wounds after debridement (NAC applied at the start of culture) or without debridement (NAC applied when biofilm is already formed). This approach can be taken to develop biofilm from microbiome taken directly from human chronic wounds to test molecules that could be effective for the treatment of specific biofilm compositions.

scholarly journals Prevention of excessive scar formation using nanofibrous meshes made of biodegradable elastomer poly(3-hydroxybutyrate-co-3-hydroxyvalerate)

2020 ◽  
Vol 11 ◽  
pp. 204173142094933 ◽  
Author(s):  
Hye Sung Kim ◽  
Junyu Chen ◽  
Lin-Ping Wu ◽  
Jihua Wu ◽  
Hua Xiang ◽  
...  
Keyword(s):  
Cell Attachment ◽  
Scar Formation ◽  
Dermal Fibroblasts ◽  
Wound Dressings ◽  
Elongation At Break ◽  
Wound Model ◽  
Solution Cast ◽  
Model Treatment

To reduce excessive scarring in wound healing, electrospun nanofibrous meshes, composed of haloarchaea-produced biodegradable elastomer poly(3-hydroxybutyrate- co-3-hydroxyvalerate) (PHBV), are fabricated for use as a wound dressing. Three PHBV polymers with different 3HV content are used to prepare either solution-cast films or electrospun nanofibrous meshes. As 3HV content increases, the crystallinity decreases and the scaffolds become more elastic. The nanofibrous meshes exhibit greater elasticity and elongation at break than films. When used to culture human dermal fibroblasts in vitro, PHBV meshes give better cell attachment and proliferation, less differentiation to myofibroblasts, and less substrate contraction. In a full-thickness mouse wound model, treatment with films or meshes enables regeneration of pale thin tissues without scabs, dehydration, or tubercular scar formation. The epidermis of wounds treated with meshes develop small invaginations in the dermis within 2 weeks, indicating hair follicle and sweat gland regeneration. Consistent with the in vitro results, meshes reduce myofibroblast differentiation in vivo through downregulation of α-SMA and TGF-β1, and upregulation of TGF-β3. The regenerated wounds treated with meshes are softer and more elastic than those treated with films. These results demonstrate that electrospun nanofibrous PHBV meshes mitigate excessive scar formation by regulating myofibroblast formation, showing their promise for use as wound dressings.

scholarly journals A gelatin/collagen/polycaprolactone scaffold for skin regeneration

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6358 ◽  
Author(s):  
Lin-Gwei Wei ◽  
Hsin-I Chang ◽  
Yiwei Wang ◽  
Shan-hui Hsu ◽  
Lien-Guo Dai ◽  
...  
Keyword(s):  
Stem Cells ◽  
Wound Healing ◽  
Dermal Fibroblasts ◽  
Skin Regeneration ◽  
Collagen Content ◽  
Wound Dressings ◽  
Skin Substitute ◽  
Epidermal Keratinocytes ◽  
Adipose Derived Stem Cells

Background A tissue-engineered skin substitute, based on gelatin (“G”), collagen (“C”), and poly(ε-caprolactone) (PCL; “P”), was developed. Method G/C/P biocomposites were fabricated by impregnation of lyophilized gelatin/collagen (GC) mats with PCL solutions, followed by solvent evaporation. Two different GC:PCL ratios (1:8 and 1:20) were used. Results Differential scanning calorimetry revealed that all G/C/P biocomposites had characteristic melting point of PCL at around 60 °C. Scanning electron microscopy showed that all biocomposites had similar fibrous structures. Good cytocompatibility was present in all G/C/P biocomposites when incubated with primary human epidermal keratinocytes (PHEK), human dermal fibroblasts (PHDF) and human adipose-derived stem cells (ASCs) in vitro. All G/C/P biocomposites exhibited similar cell growth and mechanical characteristics in comparison with C/P biocomposites. G/C/P biocomposites with a lower collagen content showed better cell proliferation than those with a higher collagen content in vitro. Due to reasonable mechanical strength and biocompatibility in vitro, G/C/P with a lower content of collagen and a higher content of PCL (GCLPH) was selected for animal wound healing studies. According to our data, a significant promotion in wound healing and skin regeneration could be observed in GCLPH seeded with adipose-derived stem cells by Gomori’s trichrome staining. Conclusion This study may provide an effective and low-cost wound dressings to assist skin regeneration for clinical use.

scholarly journals New Adapted In Vitro Technology to Evaluate Biofilm Formation and Antibiotic Activity Using Live Imaging under Flow Conditions

Diagnostics ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1746
Author(s):  
Cassandra Pouget ◽  
Catherine Dunyach-Remy ◽  
Alix Pantel ◽  
Sophie Schuldiner ◽  
Albert Sotto ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Cell Imaging ◽  
Chronic Wounds ◽  
Chronic Wound ◽  
Live Imaging ◽  
Bacterial Biofilm ◽  
Flow Conditions ◽  
Promising Tool ◽  
Reference Strains

The polymicrobial nature of biofilms and bacterial interactions inside chronic wounds are keys for the understanding of bacterial cooperation. The aim of this present study was to develop a technique to study and visualize biofilm in live imaging under flow conditions (Bioflux™ 200, Fluxion Biosciences). The BiofluxTM system was adapted using an in vitro chronic wound-like medium (CWM) that mimics the environment encountered in ulcers. Two reference strains of Staphylococcus aureus (Newman) and Pseudomonas aeruginosa (PAO1) were injected in the BiofluxTM during 24 h to 72 h in mono and coculture (ratio 1:1, bacteria added simultaneously) in the CWM vs. a control medium (BHI). The quantification of biofilm formation at each time was evaluated by inverted microscopy. After 72 h, different antibiotics (ceftazidime, imipenem, linezolid, oxacillin and vancomycin) at 1x MIC, 10x MIC and 100x MIC were administrated to the system after an automatic increase of the flow that mimicked a debridement of the wound surface. Biofilm studies highlighted that the two species, alone or associated, constituted a faster and thicker biofilm in the CWM compared to the BHI medium. The effect of antibiotics on mature or “debrided” biofilm indicated that some of the most clinically used antibiotic such as vancomycin or imipenem were not able to disrupt and reduce the biofilm biomass. The use of a life cell imaging with an in vitro CWM represents a promising tool to study bacterial biofilm and investigate microbial cooperation in a chronic wound context.

scholarly journals Dermal fibroblasts cultured from donors with type 2 diabetes mellitus retain an epigenetic memory associated with poor wound healing responses

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aaiad H. A. Al-Rikabi ◽  
Desmond J. Tobin ◽  
Kirsten Riches-Suman ◽  
M. Julie Thornton
Keyword(s):  
Diabetes Mellitus ◽  
Type 2 Diabetes ◽  
Wound Healing ◽  
Type 2 Diabetes Mellitus ◽  
Chronic Wounds ◽  
Dermal Fibroblasts ◽  
Necrosis Factor Alpha ◽  
Tnf Α

AbstractThe prevalence of Type 2 diabetes mellitus (T2DM) is escalating globally. Patients suffer from multiple complications including the development of chronic wounds that can lead to amputation. These wounds are characterised by an inflammatory environment including elevated tumour necrosis factor alpha (TNF-α). Dermal fibroblasts (DF) are critical for effective wound healing, so we sought to establish whether there were any differences in DF cultured from T2DM donors or those without diabetes (ND-DF). ND- and T2DM-DF when cultured similarly in vitro secreted comparable concentrations of TNF-α. Functionally, pre-treatment with TNF-α reduced the proliferation of ND-DF and transiently altered ND-DF morphology; however, T2DM-DF were resistant to these TNF-α induced changes. In contrast, TNF-α inhibited ND- and T2DM-DF migration and matrix metalloprotease expression to the same degree, although T2DM-DF expressed significantly higher levels of tissue inhibitor of metalloproteases (TIMP)-2. Finally, TNF-α significantly increased the secretion of pro-inflammatory cytokines (including CCL2, CXCL1 and SERPINE1) in ND-DF, whilst this effect in T2DM-DF was blunted, presumably due to the tendency to higher baseline pro-inflammatory cytokine expression observed in this cell type. Collectively, these data demonstrate that T2DM-DF exhibit a selective loss of responsiveness to TNF-α, particularly regarding proliferative and secretory functions. This highlights important phenotypic changes in T2DM-DF that may explain the susceptibility to chronic wounds in these patients.

scholarly journals An in vitro model of chronic wound biofilms to test wound dressings and assess antimicrobial susceptibilities

2010 ◽  
Vol 65 (6) ◽  
pp. 1195-1206 ◽  
Author(s):  
K. E. Hill ◽  
S. Malic ◽  
R. McKee ◽  
T. Rennison ◽  
K. G. Harding ◽  
...  
Keyword(s):  
In Vitro Model ◽  
Chronic Wound ◽  
Wound Dressings ◽  
Antimicrobial Susceptibilities ◽  
Vitro Model ◽  
Wound Biofilms

scholarly journals An EGF- and Curcumin-Co-Encapsulated Nanostructured Lipid Carrier Accelerates Chronic-Wound Healing in Diabetic Rats

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4610
Author(s):  
Hye-Jin Lee ◽  
Moses Jeong ◽  
Young-Guk Na ◽  
Sung-Jin Kim ◽  
Hong-Ki Lee ◽  
...  
Keyword(s):  
Wound Healing ◽  
Chronic Wounds ◽  
Chronic Wound ◽  
Healing Process ◽  
Double Emulsion ◽  
Average Diameter ◽  
Diabetic Rats ◽  
Wound Healing Process ◽  
Nanostructured Lipid Carrier

Nanostructured lipid carriers (NLC) are capable of encapsulating hydrophilic and lipophilic drugs. The present study developed an NLC containing epidermal growth factor (EGF) and curcumin (EGF–Cur-NLC). EGF–Cur-NLC was prepared by a modified water-in-oil-in-water (w/o/w) double-emulsion method. The EGF–Cur-NLC particles showed an average diameter of 331.8 nm and a high encapsulation efficiency (81.1% and 99.4% for EGF and curcumin, respectively). In vitro cell studies were performed using two cell types, NIH 3T3 fibroblasts and HaCaT keratinocytes. The results showed no loss of bioactivity of EGF in the NLC formulation. In addition, EGF–Cur-NLC improved in vitro cell migration, which mimics the wound healing process. Finally, EGF–Cur-NLC was evaluated in a chronic wound model in diabetic rats. We found that EGF–Cur-NLC accelerated wound closure and increased the activity of antioxidant enzymes. Overall, these results reveal the potential of the NLC formulation containing EGF and curcumin to promote healing of chronic wounds.

scholarly journals Dissolved oxygen from microalgae-gel patch promotes chronic wound healing in diabetes

2020 ◽  
Vol 6 (20) ◽  
pp. eaba4311 ◽  
Author(s):  
Huanhuan Chen ◽  
Yuhao Cheng ◽  
Jingrun Tian ◽  
Peizheng Yang ◽  
Xuerao Zhang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Wound Healing ◽  
Dissolved Oxygen ◽  
Oxygen Delivery ◽  
Chronic Wounds ◽  
Chronic Wound ◽  
Superior Performance ◽  
Gaseous Oxygen ◽  
Promote Cell Proliferation

Chronic wounds in diabetes undergo a lifetime risk of developing into diabetic foot ulcers. Oxygen is crucial to wound healing by regulating cell proliferation, migration, and neovascularization. However, current oxygen therapies, including hyperbaric oxygen (HBO) and topical gaseous oxygen (TGO), mainly employ gaseous oxygen delivery, which is much less effective in penetrating the skin. Here, we introduce an oxygen-producing patch, made of living microalgae hydrogel, which can produce dissolved oxygen. The superior performance of the patch that results from its dissolved oxygen delivery is >100-fold much more efficient than TGO penetrating the skin. Further experiments indicate that the patch could promote cell proliferation, migration, and tube formation in vitro, and improve chronic wound healing and the survival of skin grafts in diabetic mice. We believe that the microalgae-gel patch can provide continuous dissolved oxygen to improve chronic wound healing.

scholarly journals Principles of Best Diagnostic Practice in Tissue Repair and Wound Healing: An Expert Consensus

Diagnostics ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 50
Author(s):  
David G. Armstrong ◽  
Karen Bauer ◽  
Greg Bohn ◽  
Marissa Carter ◽  
Robert Snyder ◽  
...  
Keyword(s):  
Protease Activity ◽  
Pathogenic Bacteria ◽  
Chronic Wounds ◽  
Chronic Wound ◽  
Wound Care ◽  
Clinical Signs ◽  
Care Practice ◽  
Invasive Infection ◽  
Consensus Panel ◽  
Advanced Therapies

Chronic wound treatment currently relies heavily on visual assessment by clinicians; however, the clinical signs and symptoms of infection and inflammation are unreliable in chronic wounds. The specialty of wound care has witnessed the advent of advanced interventions, such as cellular and/or tissue based products (CTP). The success of advanced therapies relies on preparing the wound bed by reducing bacterial burden and inflammation. The lack of diagnostics in chronic wound care leads to uncertainty in the adequacy of wound bed preparation. Recent research suggests that two novel point-of-care diagnostic tests can assist in the detection of chronic inflammation known as elevated neutrophil derived protease activity (EPA) and bacterial pathogenesis known as bacterial protease activity(BPA) in chronic wounds. Despite the evidence, however, clinicians report that incorporating diagnostics into every day practice is challenging and across the globe, they have requested guidance on their use. Methods and Recommendations: A panel of wound care experts, experienced with these tests, met to develop guidelines on their use in wound care practice. The consensus panel concluded that the clinician should test for BPA first. The panel maintained that the risk of invasive infection resulting from the presence of pathogenic bacteria was the greatest threat to the patient’s health. If the BPA test is negative, the panel recommended testing for EPA. In addition, it was suggested that if the wound failed to progress after the elevated BPA was treated and subsequent testing was negative for BPA, the clinician should consider testing for EPA. Conclusions: In this manuscript, the consensus panel suggests pathways for testing, treating, and retesting for EPA and BPA. The panel expects that following the algorithm has the potential to improve healing outcomes, result in more cost-effective use of advanced therapies, and improve antimicrobial stewardship by guiding antimicrobial use.

Sign in / Sign up

Export Citation Format

Share Document