Impaired cutaneous wound healing in interleukin-6-deficient and immunosuppressed mice

FBP1 orchestrates keratinocyte proliferation/differentiation and suppresses psoriasis through metabolic control of histone acetylation

Keratinocyte proliferation and differentiation in epidermis are well-controlled and essential for reacting to stimuli such as ultraviolet light. Imbalance between proliferation and differentiation is a characteristic feature of major human skin diseases such as psoriasis and squamous cell carcinoma. However, the effect of keratinocyte metabolism on proliferation and differentiation remains largely elusive. We show here that the gluconeogenic enzyme fructose-1,6-bisphosphatase 1 (FBP1) promotes differentiation while inhibits proliferation of keratinocyte and suppresses psoriasis development. FBP1 is identified among the most upregulated genes induced by UVB using transcriptome sequencing and is elevated especially in upper epidermis. Fbp1 heterozygous mice exhibit aberrant epidermis phenotypes with local hyperplasia and dedifferentiation. Loss of FBP1 promotes proliferation and inhibits differentiation of keratinocytes in vitro. Mechanistically, FBP1 loss facilitates glycolysis-mediated acetyl-CoA production, which increases histone H3 acetylation at lysine 9, resulting in enhanced transcription of proliferation genes. We further find that the expression of FBP1 is dramatically reduced in human psoriatic lesions and in skin of mouse imiquimod psoriasis model. Fbp1 deficiency in mice facilitates psoriasis-like skin lesions development through glycolysis and acetyl-CoA production. Collectively, our findings reveal a previously unrecognized role of FBP1 in epidermal homeostasis and provide evidence for FBP1 as a metabolic psoriasis suppressor.

Reversibly Adhesive, Anti-Swelling, and Antibacterial Hydrogels for Tooth-Extraction Wound Healing

Oral wound treatment faces challenges due to the complex oral environment, thus, sealing the wound quickly becomes necessary. Although some materials have achieved adhesion and sterilization, how to effectively solve the contradiction between strong adhesion and on-demand removal remains a challenge. Herein, a reversibly adhesive hydrogel is designed by free radical copolymerization of cationic monomer [2-(acryloyloxy) ethyl] trimethylammonium chloride (ATAC), hydrophobic monomer ethylene glycol phenyl ether acrylate (PEA) and N-isopropylacrylamide (NIPAAm). The cationic quaternary ammonium salts provide electrostatic interactions, the hydrophobic groups provide hydrophobic interactions, and the PNIPAAm chain segments provide hydrogen bonding, leading to strong adhesion. Therefore, the hydrogel obtains an adhesion strength of 18.67 KPa to oral mucosa and can seal wounds fast within 10 s. Furthermore, unlike pure PNIPAAm, the hydrogel has a lower critical solution temperature of 40.3 °C due to the contribution of ATAC and PEA, enabling rapid removal with 40 °C water after treatment. In addition, the hydrogel realizes excellent anti-swelling ratio (≈80%) and antibacterial efficiency (over 90%). Animal experiments prove that the hydrogel effectively reduces inflammation infiltration, promotes collagen deposition and vascular regeneration. Thus, hydrogel as a multi-functional dressing has great application prospects in oral wound management.

Identification of β-cycloidal-derived mono-carbonyl curcumin analogs as potential interleukin-6 inhibitor to treat wound healing through QSAR, molecular docking, MD simulation, MM-GBSA calculation

Interleukin-6 (IL-6) is a cytokine that involved in the different phases of wound healing. It is responsible for promoting inflammation, regulating tissue repair scar formation, stimulating the production of extracellular matrix components and recruiting immune cells to the wound site. Therefore, suppressing IL-6 is beneficial for wound healing. However, no small molecules are currently available in the market against the IL-6. As a result, this research gap motivates us to find a potential inhibitor. This study aimed to investigate the wound healing potential of novel β-cycloidal-derived mono-carbonyl curcumin analogs reported in the literature through screening a series of computational studies. The calculated pIC50 value of 18 compounds (below 10) showed that all compounds may have potential therapeutic efficacy. Molecular docking studies revealed that compound C12 (-45.6044 kcal/mol) bound most strongly in the active site of IL-6 compared to the FDA-approved drug clindamycin (-42.3223). The Molecular Dynamic (MD) simulation displayed that lead compound C12 had the highest stability in the active site of IL-6 compared to the reference drug clindamycin. Furthermore, MMGBSA results indicated that C12 (-20.28 kcal/mol) had the highest binding energy compared to clindamycin (-8.36 kcal/mol). The ADMET analysis predicted that C12 are favourable for drug candidates. This study recommended compound C12 as a lead IL-6 inhibitor for future testing and development as therapeutics for wound healing.Communicated by Ramaswamy H. Sarma.

Parotid glands have a dysregulated immune response following radiation therapy

Head and neck cancer treatment often consists of surgical resection of the tumor followed by ionizing radiation (IR), which can damage surrounding tissues and cause adverse side effects. The underlying mechanisms of radiation-induced salivary gland dysfunction are not fully understood, and treatment options are scarce and ineffective. The wound healing process is a necessary response to tissue injury, and broadly consists of inflammatory, proliferative, and redifferentiation phases with immune cells playing key roles in all three phases. In this study, select immune cells were phenotyped and quantified, and certain cytokine and chemokine concentrations were measured in mouse parotid glands after IR. Further, we used a model where glandular function is restored to assess the immune phenotype in a regenerative response. These data suggest that irradiated parotid tissue does not progress through a typical inflammatory response observed in wounds that heal. Specifically, total immune cells (CD45+) decrease at days 2 and 5 following IR, macrophages (F4/80+CD11b+) decrease at day 2 and 5 and increase at day 30, while neutrophils (Ly6G+CD11b+) significantly increase at day 30 following IR. Additionally, radiation treatment reduces CD3- cells at all time points, significantly increases CD3+/CD4+CD8+ double positive cells, and significantly reduces CD3+/CD4-CD8- double negative cells at day 30 after IR. Previous data indicate that post-IR treatment with IGF-1 restores salivary gland function at day 30, and IGF-1 injections attenuate the increase in macrophages, neutrophils, and CD4+CD8+ T cells observed at day 30 following IR. Taken together, these data indicate that parotid salivary tissue exhibits a dysregulated immune response following radiation treatment which may contribute to chronic loss of function phenotype in head and neck cancer survivors.

Anti-bacterial and anti-inflammatory properties of Vernonia arborea accelerate the healing of infected wounds in adult Zebrafish

BACKGROUND

Management of wounds and healing under impaired conditions are the major challenges faced globally by healthcare workers. Phytocompounds which are anti-microbial and capable of modulating inflammation contribute to overall wound healing and regain of the lost structure and function especially in wounds impaired with polymicrobial infection.

METHODS

An acute cutaneous impaired wound model using adult zebrafish was validated to simulate mammalian wound pathophysiology. This model was used to evaluate phytofractions of Vernonia arborea in the present study, for reduction of infection; myeloperoxidase (MPO) as a marker of infection; neutrophil infiltration and resolution; kinetics of inflammatory cytokines; and wound repair kinetics (viz., nitrite levels and iNoS expression; reepithelisation).

RESULTS

Four fractions which were active in-vitro against five selected wound microbes were shown to reduce ex-vivo microbial bioburden upto 96% in the infected wound tissue. The reduction in CFU correlated with the neutrophil kinetics and MPO enzyme levels in the treated, wound infected zebrafish. Expression of pro-inflammatory cytokines (IL-6 and TNF-α) was downregulated while upregulating anti-inflammatory cytokine (IL-10), and nitric oxide signalling with fourfold increase in iNOS expression. The adult zebrafish wound model could well serve as a standard tool for assessing phytoextracts such as V. arborea for wound healing with anti-microbial properties.

Arecoline Induces ROS Accumulation, Transcription of Proinflammatory Factors, and Expression of KRT6 in Oral Epithelial Cells

Areca nut is a major contributor to the high prevalence of oral cancer in Asia. The precise mechanisms by which areca nut stimulates mucosal cells and contributes to the progression of oral cancer urgently require clarification. The current study aimed to assess the effects of arecoline on the normal human gingival epithelium cell line S-G. Cell viability, levels of reactive oxygen species (ROS), protein expression, cellular morphology, and gene expression were evaluated using the MTT test, flow cytometry, Western blot analysis, optical or confocal microscopy, and RT-qPCR. Keratin (KRT6) analysis involved matched normal and cancer tissues from clinical head and neck specimens. The results demonstrated that 12.5 µg/mL of arecoline induced ROS production, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) mRNA expression in S-G cells. This activation of the MAPK/ERK pathway increased KRT6 expression while limiting cell migration. In head and neck cancer tissues, KRT6B gene expression exceeded that of normal tissues. This study confirms that arecoline induces ROS accumulation in normal cells, leading to the secretion of proinflammatory factors and KRT6 expression. This impedes oral mucosal healing, thereby promoting the progression of oral cancer.

CCL3 Promotes Cutaneous Wound Healing Through Recruiting Macrophages in Mice

Wound healing is a complex process, which involves three stages: inflammation, proliferation, and remodeling. Inflammation is the first step; thus, immune factors play an important regulatory role in wound healing. In this study, we focused on a chemokine, C-C motif chemokine ligand 3 (CCL3), which is often upregulated for expression during wound healing. We compared cutaneous wound healing at the histological, morphological, and molecular levels in the presence and absence of CCL3. The results showed that the wound healing rate in the wild-type and CCL3-/- + CCL3 mice was faster than that of CCL3-/- mice (P < 0.01), and application of CCL3 to wounds increased the healing rate. In the process of wound healing, the degree of reepithelialization and the rate of collagen deposition in the wound of CCL3-/- mice were significantly lower than those of wild-type mice (P < 0.01). The number of macrophages and the expression levels of tumor necrosis factor(TNF)-α and transforming growth factor (TGF)-β1 in the wounds of wild-type mice were much higher than those of the CCL3-/- mice. Removal of macrophages and CCL3-/- mice share similar phenotypes. Therefore, we infer that the wound healing requires the participation of macrophages, and CCL3 may play an important regulatory role through recruiting macrophages to the wound sites.

The influence of negative pressure wound therapy on bacterial and fungal growth

BACKGROUND

The use of negative pressure wound therapy (NPWT) in superinfected wounds is controversial. The mechanism of action is unclear, but recent studies have shown lower atmospheric oxygen levels within the dressing. Therefore, different oxygen-favoring bacteria and fungi might benefit or face impaired thriving conditions. The aim of this in vitro study is to investigate the influence of NPWT on bacterial and fungal growth.

METHODS

Salmonella enterica subsp. enterica serovar Typhimurium, Pseudomonas aeruginosa and Candida albicans strains were cultured on concentrated agars and attached to a standard NPWT-device. After 48 hours, colonies were separately harvested from the agar and foam. Optical density (OD) was obtained in order to estimate bacterial loads.

RESULTS

For all tested microorganisms, no overall significant differences were found compared to controls. Subanalysis showed lower OD levels from the agar beneath the foam in the NPWT-group.

CONCLUSION

NPWT removed bacteria and fungi from the wound surface but accumulation is found within the foam. The use of NPWT showed no influence on bacterial or fungal growth selection. With superinfected wounds, the use of NPWT should thoroughly be evaluated as toxins and virulence factors may not fully be evacuated.

A short-term high-sugar diet is an aggravating factor in experimental allergic contact dermatitis

Allergic contact dermatitis (ACD) is an inflammatory skin reaction whose incidence has increased and has been associated with a dietary pattern rich in saturated fats and refined sugars. Considering the increased incidence of ACD and the lack of research about the influence of a short-term high-sugar diet on dermatitis, our aim is to improve understanding of the influence of a high-sugar diet on ACD. We introduced a diet rich in sugar fifteen days before inducing contact dermatitis with oxazolone, in mice, and maintained it until the end of the experiment, which lasted three weeks in total. The dermatitis model increased cholesterol and triglycerides in the liver, and the combination of diet and dermatitis increased weight and worsened liver cholesterol measurements. Furthermore, the high-sugar diet increased the production of IL-6, IFN-γ and TNF-α in the skin, which may be involved in the increase in epithelial skin thickness observed in experimental ACD.

Topical application of Lactobacilli successfully eradicates Pseudomonas aeruginosa biofilms and promotes wound healing in chronic wounds

Chronic wounds are difficult to treat due to the presence of biofilm which prevents wound healing. Pseudomonas aeruginosa is one of the most common pathogens found in chronic wounds and conventional treatment strategies have been ineffective in the eradication of its biofilm, without harming the surrounding healthy tissue at the same time. Here, we introduced an innovative approach applying the probiotic product Bio-K+ (containing three lactobacilli) topically as an antimicrobial and antibiofilm agent. We identified lactic acid as the main active component. While antibiotics and antiseptics such as silver-ions only demonstrated limited efficacy, Bio-K+ was able to completely eradicate mature P. aeruginosa biofilms established in an in-vitro and ex-vivo human skin model. Furthermore, it demonstrated biocompatibility in the co-culture with human dermal fibroblasts and accelerated the migration of fibroblasts in a cell migration assay promoting wound healing. To enhance clinical practicability, we introduced Bio-K+ into the hydrocolloid dressing Aquacel, achieving sustained release of lactic acid and biofilm eradication. This new treatment approach applying probiotics could represent a major improvement in the management of chronic wounds and can be extended in treating other biofilm-associated infections.

Wound-Induced Hair Follicle Neogenesis as a Promising Approach for Hair Regeneration

The mammalian skin contains hair follicles, which are epidermal appendages that undergo periodic cycles and exhibit mini-organ features, such as discrete stem cell compartments and different cellular components. Wound-induced hair follicle neogenesis (WIHN) is the remarkable ability to regenerate hair follicles after large-scale wounding and occurs in several adult mammals. WIHN is comparable to embryonic hair follicle development in its processes. Researchers are beginning to identify the stem cells that, in response to wounding, develop into neogenic hair follicles, as well as to understand the functions of immune cells, mesenchymal cells, and several signaling pathways that are essential for this process. WIHN represents a promising therapeutic approach to the reprogramming of cellular states for promoting hair follicle regeneration and preventing scar formation. In the scope of this review, we investigate the contribution of several cell types and molecular mechanisms to WIHN.

Current insights in the preclinical study of palatal wound healing and oronasal fistula after cleft palate repair

Poor palatal wound healing after cleft palate repair could lead to unfavorable prognosis such as oronasal fistula (ONF), which might affect the patient's velopharyngeal function as well as their quality of life. Thus, restoring poor palatal wound healing for avoiding the occurrence of ONF should be considered the key to postoperative care after cleft palate repair. This review provided current insights in the preclinical study of poor palatal wound healing after cleft palate repair. This review comprehensively introduced the animal model establishment for palatal wound healing and related ONF, including the models by mice, rats, piglets, and dogs, and then demonstrated the aspects for investigating poor palatal wound healing and related treatments, including possible signaling pathways that could be involved in the formation of poor palatal wound healing, the related microbiota changes because of the deformity of palatal structure, and the studies for potential therapeutic strategies for palatal wound healing and ONF. The purpose of this review was to show the state of the art in preclinical studies about palatal wound healing after cleft palate repair and to show the promising aspects for better management of palatal wound healing.

Analysis of the impact of different schemes of preparation to trabeculectomy on the healing markers on the Tenon fibroblasts cultures

The aim of the study was to assess the influence of different regimes of patient's preparation before trabeculectomy on the markers of healing process in Tenon's fibroblast cultures.The studied group consisted of 66 patients with open angle glaucoma undergoing primary trabeculectomy. The patients were divided into 5 groups with different regimes of preparation before the surgery based on application or withdrawal of topical antiglaucoma medications and steroids (G1-patients using antiglaucoma drops until the day of the surgery; G2-patients using antiglaucoma drops until the day of the surgery and additionally dexamethasone for 4 weeks before surgery; G3-patients who stopped using antiglaucoma drops 4 weeks before the surgery and introduced dexamethasone for 4 weeks before surgery; G4-patients who stopped using antiglaucoma drops 4 weeks before the surgery; G5-control group, patients with newly diagnosed glaucoma in whom trabeculectomy was the first treatment option without medical treatment). During trabeculectomy the samples of Tenon's capsule were obtained. Tenon fibroblasts were isolated directly from the explants to test their proliferation ability and the level of released healing markers. Following factors typical of healing process were evaluated using commercially available ELISA kits: IL 1-β, IL-6, IL-8, VEGF-A, TGF-β1 and MMP-9. Concentrations of IL-1β, IL-6 and TGF-β1 were significantly higher in the group obtaining antiglaucoma drops. Additionally, in this group the fibroblasts revealed the highest proliferation potential, indicating the active healing process. The levels of IL-8, VEGF-A and MMP-9 were similar between the groups. Our study shows that for the best conjunctival anti-inflammatory control, the most influential factor is the withdrawal of antiglaucoma medications.

Mechanisms and applications of adipose-derived stem cell-extracellular vesicles in the inflammation of wound healing

Wound healing is a sophisticated process consisting of serial phases with overlaps, including hemostasis, inflammation, proliferation, and remodeling. The inflammation response is an early response that plays a crucial role in eliminating microbes and clearing damaged cell debris. However, in some pathological circumstances, such as diabetes mellitus, ischemia, trauma, deep burn, etc., abnormal inflammation can cause impaired wound healing. Adipose-derived stem cells (ADSCs) belong to the mesenchymal stem cell (MSC) family and exhibit prospective applications in tissue regeneration and dermatological repairs. ADSC-secreted extracellular vesicles (ADSC-EVs) mimic the functions of ADSCs without the concerns of cell survival, immune response, or ethical issues. Studies have revealed that ADSC-EVs can inhibit abnormal inflammation responses and accelerate wound healing through various mechanisms. Moreover, some studies explored modifications in the cargo components of ADSC-EVs to enhance their therapeutic efficacy. Given the increasing studies focusing on the potential of ADSC-EVs in wound healing, how they interfere with different phases of this process has been investigated in pieces. In this review, we summarized all up-to-date evidence to map a clearer picture of the underlying mechanisms of ADSC-EVs in inflammation response. The applications of ADSC-EVs aiming at inflammation in the healing process were also reviewed to provide therapeutic strategies for future investigators.

Wound Restorative Power of Halimeda macroloba/ Mesenchymal Stem Cells in Immunocompromised Rats via Downregulating Inflammatory/Immune Cross Talk

Impaired skin wound healing is still a major challenge, especially with immunocompromised patients who express delayed healing and are susceptible to infections. Injection of rat-derived bone marrow mesenchymal stem cells (BMMSCs) via the tail vein accelerates cutaneous wound healing via their paracrine activity. The present work aimed to investigate the combined wound-healing potential of BMMSCs and Halimeda macroloba algae extract in immunocompromised rats. High-resolution liquid chromatography-mass spectrometry (HR-LC-MS) investigation of the extract revealed the presence of variant phytochemicals, mostly phenolics, and terpenoids, known for their angiogenic, collagen-stimulating, anti-inflammatory, and antioxidant properties. The BMMSCs were isolated and characterized for CD markers, where they showed a positive expression of CD90 by 98.21% and CD105 by 97.1%. Twelve days after inducing immunocompromise (40 mg/kg hydrocortisone daily), a circular excision was created in the dorsal skin of rats and the treatments were continued for 16 days. The studied groups were sampled on days 4, 8, 12, and 16 after wounding. The gross/histopathological results revealed that the wound closure (99%), thickness, density of new epidermis and dermis, and skin elasticity in the healed wounds were considerably higher in the BMMSCs/Halimeda group than the control group (p < 0.05). RT-PCR gene expression analysis revealed that the BMMSCs/Halimeda extract combination had perfectly attenuated oxidative stress, proinflammatory cytokines, and NF-_KB activation at day 16 of wounding. The combination holds promise for regenerative medicine, representing a revolutionary step in the wound healing of immunocompromised patients, with still a need for safety assessments and further clinical trials.

Purification of PaTx-II from the Venom of the Australian King Brown Snake and Characterization of Its Antimicrobial and Wound Healing Activities

Infections caused by multi-drug-resistant (MDR) bacteria are a global threat to human health. As venoms are the source of biochemically diverse bioactive proteins and peptides, we investigated the antimicrobial activity and murine skin infection model-based wound healing efficacy of a 13 kDa protein. The active component PaTx-II was isolated from the venom of Pseudechis australis (Australian King Brown or Mulga Snake). PaTx-II inhibited the growth of Gram-positive bacteria in vitro, with moderate potency (MICs of 25 µM) observed against S. aureus, E. aerogenes, and P. vulgaris. The antibiotic activity of PaTx-II was associated with the disruption of membrane integrity, pore formation, and lysis of bacterial cells, as evidenced by scanning and transmission microscopy. However, these effects were not observed with mammalian cells, and PaTx-II exhibited minimal cytotoxicity (CC₅₀ > 1000 µM) toward skin/lung cells. Antimicrobial efficacy was then determined using a murine model of S. aureus skin infection. Topical application of PaTx-II (0.5 mg/kg) cleared S. aureus with concomitant increased vascularization and re-epithelialization, promoting wound healing. As small proteins and peptides can possess immunomodulatory effects to enhance microbial clearance, cytokines and collagen from the wound tissue samples were analyzed by immunoblots and immunoassays. The amounts of type I collagen in PaTx-II-treated sites were elevated compared to the vehicle controls, suggesting a potential role for collagen in facilitating the maturation of the dermal matrix during wound healing. Levels of the proinflammatory cytokines interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2) and interleukin-10 (IL-10), factors known to promote neovascularization, were substantially reduced by PaTx-II treatment. Further studies that characterize the contributions towards efficacy imparted by in vitro antimicrobial and immunomodulatory activity with PaTx-II are warranted.

Negative Pressure Wound Therapy with Instillation: Analysis of the Rinsing Fluid as a Monitoring Tool and Approach to the Inflammatory Process: A Pilot Study

BACKGROUND

Negative pressure wound therapy with instillation (NPWTi) is an established wound conditioning tool. Previous investigations discovered that the rinsing fluid is a suitable monitoring tool containing various cells and cytokines.

METHODS

The aim of this pilot study was to analyze rinsing fluid samples from patients treated with NPWTi and link them to the clinical course, including microbiological contamination. In 31 consecutive patients with acute and chronic wounds, laboratory analysis was performed to evaluate IL-6, IL-8, bFGF, Tnf-a, and VEGF.

RESULTS

IL-6 showed a significant increase to 1540 pg/mL on day two and 860 pg/mL on day four (p = 0.01 and p = 0.04, resp.). IL-8 steadily increased from a median of 2370 pg/mL to a maximum of 19,400 pg/mL on day three (p = 0.01). The median bFGF showed a steady decline from 22 pg/mL to 10 pg/m (p = 0.35) on day three. The median Tnf-a increased from 11 pg/mL to 44 pg/mL (p = 001). The median VEGF values fluctuated but showed an overall increase from 35 pg/mL to 250 pg/mL (p = 0.07). Regarding IL-8, diabetic and non-diabetic patients both showed a gradual increase with non-significant higher median values for the diabetics. The subgroup analysis of IL-6 showed increasing and higher values in cases with bacterial superinfections (p = 0.07).

CONCLUSION

We were able to use an established wound conditioning tool to gather important information about the inflammatory response during NPWTi treatment. Cytokine and cell courses were mostly consistent with the literature, especially in diabetic patients, and should be further investigated.

The Effects of Combined Exposure to Simulated Microgravity, Ionizing Radiation, and Cortisol on the In Vitro Wound Healing Process

Human spaceflight is associated with several health-related issues as a result of long-term exposure to microgravity, ionizing radiation, and higher levels of psychological stress. Frequent reported skin problems in space include rashes, itches, and a delayed wound healing. Access to space is restricted by financial and logistical issues; as a consequence, experimental sample sizes are often small, which limits the generalization of the results. Earth-based simulation models can be used to investigate cellular responses as a result of exposure to certain spaceflight stressors. Here, we describe the development of an in vitro model of the simulated spaceflight environment, which we used to investigate the combined effect of simulated microgravity using the random positioning machine (RPM), ionizing radiation, and stress hormones on the wound-healing capacity of human dermal fibroblasts. Fibroblasts were exposed to cortisol, after which they were irradiated with different radiation qualities (including X-rays, protons, carbon ions, and iron ions) followed by exposure to simulated microgravity using a random positioning machine (RPM). Data related to the inflammatory, proliferation, and remodeling phase of wound healing has been collected. Results show that spaceflight stressors can interfere with the wound healing process at any phase. Moreover, several interactions between the different spaceflight stressors were found. This highlights the complexity that needs to be taken into account when studying the effect of spaceflight stressors on certain biological processes and for the aim of countermeasures development.

Bioactivity analysis of calcium silicate-based sealers and repair cements on the phenotype and cytokine secretion profile of CD14+ monocytes: An ex vivo study

AIM

This study evaluated the immune bioactivity of testing media (TM) obtained from different calcium silicate-based sealers and cements on monocyte morphology, activation, differentiation and cytokine secretion.

METHODS

Blood-derived CD14⁺ monocytes were isolated and cultured for 5 days with 25% TM from the following calcium silicate-based materials: TotalFill BC RRM Fast-Set Putty, Biodentine, TotalFill BC Sealer and BioRoot-Root-Canal-Sealer (RCS). A resin-based endodontic cement was used as a control. The expression of surface markers such as CD86, HLA-DR, CD16, CD309 and CD209, and cytokine secretion were analysed by flow cytometry. Data were analysed using the one-way repeated measures analysis of variance (anova) multiple comparison test and a Holm-Sidak multiple comparison post-hoc test (p < .05).

RESULTS

This comparative analysis revealed that monocytes co-cultured with calcium silicate-based materials showed a spindle-shaped morphology compared with the round shape observed in the control. Regarding activation markers, BioRoot-RCS and Biodentine significantly increased CD86 expression compared with the control sample, whereas no significant differences (p > .05) were observed in HLA-DR expression. In addition, no differences were observed among the differentiation markers. When the inflammatory cytokines were analysed, BioRoot-RCS increased the secretion of IL-1β, IL-6, IL-10 and TNF-α, whereas BioRoot-RCS and Biodentine significantly decreased IL-8 production (p < .05).

CONCLUSIONS

These data showed that the calcium silicate-based materials tested changed the morphology of CD14⁺ monocytes; however, only BioRoot-RCS and Biodentine significantly upregulated CD86. In addition, BioRoot-RCS was the sealer with the highest immunomodulatory properties for cytokine production which means that it can contribute with the in vivo healing process and regeneration of periapical lesions.

Animal models for the study of acute cutaneous wound healing

The process of wound healing is critical to maintaining homeostasis after injury. Although a considerable amount has been learned about this complex process, much remains unknown. Whereas, studies with human volunteers are ideal given the unique nature of the human skin anatomy and immune system, the lack of such clinical access has made animal models prime candidates for use in preclinical studies. This review aims to discuss the strengths and limitations of the commonly used mammalian species in wound healing studies: murine, rabbit and porcine. Thereafter, a survey of models of various acute wounds such as cutaneous, ear, and implant are presented and representative studies that use them are described. This review is intended to acquaint readers with the vast spectrum of models available, each of which has a distinct utility. At the same time, it highlights the importance of utilising clinical samples to complement investigations conducted in animal models. Through this strategy, it is hoped that forthcoming research may be more reflective of the acute wound healing process as it occurs in humans.

The Role of IL-6 in Fibrotic Diseases: Molecular and Cellular Mechanisms

Fibrosis is a detrimental outcome of most chronic inflammatory disorders and is defined by the buildup of excess extracellular matrix (ECM) components, which eventually leads to organ failure and death. Interleukin 6 (IL-6) is promptly produced by immune cells in response to tissue injuries and has a wide range of effects on cellular processes such as acute responses, hematopoiesis, and immune reactions. Furthermore, high levels of IL-6 have been found in a variety of chronic inflammatory disorders characterized by fibrosis, and this factor plays a significant role in fibrosis in various organs via Janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3) activation. Here, we review what is known about the role of IL-6 in fibrosis and why targeting IL-6 for fibrotic disease treatment makes sense.

NLRC3 deficiency promotes cutaneous wound healing due to the inhibition of p53 signaling

Cutaneous wound healing is a complicated process that is characterized by an initial inflammatory phase followed by a proliferative phase. NLRC3 plays important roles in innate immunity, inflammatory regulation and tumor cell growth. However, the function of NLRC3 in wound healing remains unclear. Here, we investigated the function of NLRC3 in acute cutaneous wound healing using Nlrc3 gene knockout (Nlrc3^-/-) mice. Our results demonstrated that skin wound repair in Nlrc3^-/- mice was significantly accelerated compared with that in wild-type (WT) mice. NLRC3 deficiency promoted the inflammatory and proliferative phases in wounds enhanced the inflammatory response and increased re-epithelialization and granulation tissue formation, and these phenotypes were primarily ascribed to regulatory effects on p53 signaling. Mechanistically, we uncovered novel crosstalk between NLRC3 and p53 signaling and revealed that NLRC3 could mediate the ubiquitination and degradation of p53 in an Hsp90-dependent manner. In conclusion, our study suggests that NLRC3 is a critical negative regulator of the inflammatory response and cell proliferation during wound healing and that blocking NLRC3 may represent a potential approach for accelerating wound healing.

Mindfulness-based stress reduction increases stimulated IL-6 production among lonely older adults: A randomized controlled trial

Loneliness is a potent psychosocial stressor that predicts poor health and mortality among older adults, possibly in part by accelerating age-related declines in immunocompetence. Mindfulness interventions have shown promise for reducing loneliness and improving markers of physical health. In a sample of lonely older adults, this two-arm parallel trial tested whether mindfulness training enhances stimulated interleukin-6 (IL-6) production, a measure of innate immune responsivity. Lonely older adults (65-85 years; N = 190) were randomized to an 8-week Mindfulness-Based Stress Reduction (MBSR) or control Health Enhancement Program (HEP) intervention. Lipopolysaccharide (LPS)-stimulated production of IL-6 was measured in vitro by blinded outcome assessors at pre-intervention, post-intervention, and 3-month follow-up. Mixed-effects linear models tested time (pre, post, follow-up) by condition (MBSR vs. HEP) effects. As predicted, a significant time × condition effect on stimulated IL-6 production was observed across pre, post, and follow-up timepoints. Significant MBSR vs. HEP differences emerged from pre- to post-intervention (p =.009, d = 0.38) and from pre-intervention to 3-month follow-up (p =.017, d = 0.35), with larger increases in IL-6 production following MBSR compared to HEP. No study-related adverse events were reported. Results show that mindfulness training may be effective for boosting innate immunocompetence among lonely older adults. Given that immunocompetence tends to decline with age, mindfulness training may help to counteract the effects of aging and psychosocial stress on infection risk and recovery from injury.

Single-cell transcriptomics reveals a senescence-associated IL-6/CCR6 axis driving radiodermatitis

Irradiation‐induced alopecia and dermatitis (IRIAD) are two of the most visually recognized complications of radiotherapy, of which the molecular and cellular basis remains largely unclear. By combining scRNA‐seq analysis of whole skin‐derived irradiated cells with genetic ablation and molecular inhibition studies, we show that senescence‐associated IL‐6 and IL‐1 signaling, together with IL‐17 upregulation and CCR6⁺‐mediated immune cell migration, are crucial drivers of IRIAD. Bioinformatics analysis colocalized irradiation‐induced IL‐6 signaling with senescence pathway upregulation largely within epidermal hair follicles, basal keratinocytes, and dermal fibroblasts. Loss of cytokine signaling by genetic ablation in IL‐6^−/− or IL‐1R^−/− mice, or by molecular blockade, strongly ameliorated IRIAD, as did deficiency of CCL20/CCR6‐mediated immune cell migration in CCR6^−/− mice. Moreover, IL‐6 deficiency strongly reduced IL‐17, IL‐22, CCL20, and CCR6 upregulation, whereas CCR6 deficiency reciprocally diminished IL‐6, IL‐17, CCL3, and MHC upregulation, suggesting that proximity‐dependent cellular cross talk promotes IRIAD. Therapeutically, topical application of Janus kinase blockers or inhibition of T‐cell activation by cyclosporine effectively reduced IRIAD, suggesting the potential of targeted approaches for the treatment of dermal side effects in radiotherapy patients.

Modulatory Effect of Diosmin and Diosmetin on Metalloproteinase Activity and Inflammatory Mediators in Human Skin Fibroblasts Treated with Lipopolysaccharide

Diosmin is widely used as a venoactive drug in the pharmacological treatment of chronic venous disorders. It exerts a strong protective effect on blood vessels via an increase in the elasticity of vessel walls and reduces the permeability of capillary walls, thereby producing an anti-edematous effect. In this paper, we investigated the effectiveness of diosmin and diosmetin in modulating the level of proinflammatory factors in human skin fibroblasts treated with lipopolysaccharide (LPS). Two variants of the experiments were performed: the flavonoid was added 2 h prior to or 24 h after LPS stimulation. Our study revealed that both flavonoids reduced the levels of IL-6 and Il-1β as well as COX-2 and PGE2 but had no impact on IL-10. However, the addition of the compounds prior to the LPS addition was more effective. Moreover, diosmetin modulated the proinflammatory factors more strongly than diosmin. Our investigations also showed that both flavonoids were potent inhibitors of elastase and collagenase activity, and no differences between the glycoside and aglycone forms were observed.

Cytokines and Venous Leg Ulcer Healing-A Systematic Review

Venous leg ulcers (VLUs) are the most common type of leg ulcers with a significant socioeconomic burden due to slow healing. Cytokines may be involved in the pathogenesis of VLUs. In this systematic review, our objective was to investigate the association between cytokine levels, including growth factors, with the healing of VLUs. PubMed, Embase, Web of Science and Cochrane Library were searched from their inception to August 2021. We retrieved 28 articles investigating 38 different cytokines in 790 patients. Cytokines were most commonly investigated in wound fluid and less frequently in biopsies and serum. The studies were judged as having a moderate to high risk of bias, and the results were often inconsistent and sometimes conflicting. A meta-analysis was not performed due to clinical and methodological heterogeneities. We found weak evidence for elevated IL-1α, IL-6, IL-8, TNF-α and VEGF levels in non-healing VLUs, an elevation that declined with healing. TGF-β1 levels tended to increase with VLU healing. Other cytokines warranting further investigations include EGF, FGF-2, GM-CSF, IL-1β, IL-1Ra and PDGF-AA/PDGF-BB. We conclude that non-healing VLUs may be associated with an elevation of a palette of pro-inflammatory cytokines, possibly reflecting activated innate immunity in these wounds. There is a paucity of reliable longitudinal studies monitoring the dynamic changes in cytokine levels during wound healing.

Mesenchymal Stem Cell-Immune Cell Interaction and Related Modulations for Bone Tissue Engineering

Critical bone defects and related delayed union and nonunion are still worldwide problems to be solved. Bone tissue engineering is mainly aimed at achieving satisfactory bone reconstruction. Mesenchymal stem cells (MSCs) are a kind of pluripotent stem cells that can differentiate into bone cells and can be used as one of the key pillars of bone tissue engineering. In recent decades, immune responses play an important role in bone regeneration. Innate immune responses provide a suitable inflammatory microenvironment for bone regeneration and initiate bone regeneration in the early stage of fracture repair. Adaptive immune responses maintain bone regeneration and bone remodeling. MSCs and immune cells regulate each other. All kinds of immune cells and secreted cytokines can regulate the migration, proliferation, and osteogenic differentiation of MSCs, which have a strong immunomodulatory ability to these immune cells. This review mainly introduces the interaction between MSCs and immune cells on bone regeneration and its potential mechanism, and discusses the practical application in bone tissue engineering by modulating this kind of cell-to-cell crosstalk. Thus, an in-depth understanding of these principles of bone immunology can provide a new way for bone tissue engineering.

Extracellular Vesicles from HIF-1α-Overexpressing Adipose-Derived Stem Cells Restore Diabetic Wounds Through Accelerated Fibroblast Proliferation and Migration

PURPOSE

Inhibition of cellular adaptation to hypoxia can cause persistent inflammation, thereby increasing tissue damage and complicating wound healing in diabetes patients. Regulating cellular adaptation to hypoxic environments can help in effective wound repair. Hypoxia-inducible factor (HIF)-1α is a key regulator of cell hypoxia. Extracellular vesicles (EVs) regulate wound repair. This study investigated the mechanism of HIF-1α overexpression in adipose-derived stem cell extracellular vesicles (ADSCs-hEVs) in the repair of diabetic wounds.

MATERIALS AND METHODS

HIF-1α expression in diabetes patients and healthy participants was studied. High-throughput sequencing, GO, and KEGG analysis revealed that ADSCs small extracellular vesicle hypoxia environments may increase HIF-1α expression by affecting cell metabolism, differentiation, and TGF-β secretion, or by altering the PI3K/AKT pathway. Effect of addition of ADSCs-hEVs on cell proliferation and migration was investigated using Western blotting, EdU assay, transwell assay, and migration. In vivo, after 7, 14, and 21 days, important factors for diabetic wound healing were evaluated by immunohistochemistry, qRT-PCR, Masson staining, and H&E staining.

RESULTS

HIF-1α expression decreased in the skin of diabetes patients; interleukin (IL)-6 expression increased, and growth factor-related indexes decreased. ADSCs-hEVs significantly increased the expression and secretion of growth factors, compared with ADSCs-EVs. In vivo, ADSC-hEV treatment accelerated the healing rate and improved the healing quality of diabetic wounds compared with ADSCs-EVs.

CONCLUSION

Speed and quality of wound healing increased significantly in the ADSCs-hEVs group, which could inhibit early inflammation while promoting the secretion and expression of growth factors and extracellular matrix-related indexes.

A platelet-derived hydrogel improves neovascularisation in full thickness wounds

Platelets are a reservoir of growth factors, cytokines and chemokines involved in spontaneous wound repair. In this study, a platelet-rich and fibrin-rich hydrogel was generated from expired platelet components that would have otherwise been transfused. The material contained physiological concentrations of transforming growth factor β1 (TGF-β1, platelet-derived growth factor AB (PDGF-AB), PDGF-BB, insulin-like growth factor-1 (IGF-1), fibroblast growth factor 2 (FGF-2), and epidermal growth factor (EGF). The effect of the hydrogel on wound repair was investigated in SKH-1 mice. Full thickness dorsal wounds were created on the mice and treated with the hydrogel at various concentrations. Immunohistochemical staining with CD31 (endothelial cell marker) revealed that wounds treated with the hydrogel showed significantly enhanced vascularisation in the wound bed. Moreover, high levels of interleukin-6 (IL-6) and KC (IL-8 functional homologue) in treated wounds were sustained over a longer period of time, compared to untreated wounds. We postulate that sustained IL-6 is a driver, at least partly, of enhanced vascularisation in full thickness wounds treated with the hydrogel. Future work is needed to explore whether this hydrogel can be utilised as a treatment option when vascularisation is a critical limitation. STATEMENT OF SIGNIFICANCE: The economic cost of wound repair is estimated in billions of dollars each year. In many cases time required to vascularise wounds is a major contributor to slow wound repair. In this study, we developed a blood-derived platelet- and fibrin-rich hydrogel. It contains a number of growth factors actively involved in spontaneous wound healing. This hydrogel significantly improved dermal repair and vascularisation in a full-thickness wound mouse model. This study provides an action mechanism for modulation of localised inflammation.

Depilatory creams increase the number of hair follicles, and dermal fibroblasts expressing interleukin-6, tumor necrosis factor-α, and tumor necrosis factor-β in mouse skin

Besides using for hair removal, depilatory agents have been considered to be used as a penetration enhancer for transepidermal drug delivery. To examine the effect in hair follicles (HFs), two commercially available depilatory creams were tested on the dorsal skin of mice to monitor the effect deep into the skin structure. Fifteen male BALB/c mice were used in this study. Depilatory creams were applied to the dorsal skin of the same animal using shaved and untouched treatments as controls to minimize individual differences. Skin samples were collected at three days, one week and two weeks (n = 5 for each) after the treatment, and subjected for hematoxylin-eosin staining, and immunohistochemical analysis for proinflammatory cytokines. The morphological examination showed an increase in the thickness of epidermal layer of the depilatory cream-treated skin at early time points and in the subcutis at two weeks. Depilatory cream promoted entry of anagen phase and increased the number of hair follicles in the subcutis at one and two weeks. Immunohistochemistry showed elevated percentages of dermal fibroblasts expressing interleukin-6, tumor necrosis factor-α, and tumor necrosis factor-β. Shaving process increased the thickness of epidermis and dermis as depilatory creams did, but did neither induce the expression of proinflammatory cytokines in the dermal fibroblasts nor the number of HFs. The results suggested that the commercially available depilatory creams caused a transient minor inflammatory response of the skin and increased the levels of cytokines that might subsequently affect hair growth.

New insights into IL-6 family cytokines in metabolism, hepatology and gastroenterology

IL-6 family cytokines are defined by the common use of the signal-transducing receptor chain glycoprotein 130 (gp130). Increasing evidence indicates that these cytokines are essential in the regulation of metabolic homeostasis as well as in the pathophysiology of multiple gastrointestinal and liver disorders, thus making them attractive therapeutic targets. Over the past few years, therapies modulating gp130 signalling have grown exponentially in several clinical settings including obesity, cancer and inflammatory bowel disease. A newly engineered gp130 cytokine, IC7Fc, has shown promising preclinical results for the treatment of type 2 diabetes, obesity and liver steatosis. Moreover, drugs that modulate gp130 signalling have shown promise in refractory inflammatory bowel disease in clinical trials. A deeper understanding of the main roles of the IL-6 family of cytokines during homeostatic and pathological conditions, their signalling pathways, sources of production and target cells will be crucial to the development of improved treatments. Here, we review the current state of the role of these cytokines in hepatology and gastroenterology and discuss the progress achieved in translating therapeutics targeting gp130 signalling into clinical practice.

Topical Administration of Heat-Killed Enterococcus faecalis Strain KH2 Promotes Re-Epithelialization and Granulation Tissue Formation during Skin Wound-Healing

Lactic acid bacteria (LAB) are known to have beneficial effects on immune responses when they are orally administered as bacterial products. Although the beneficial effects of LAB have been reported for the genera Lactobacillus and Lactococcus, little has been uncovered on the effects of the genus Enterococcus on skin wound-healing. In this study, we aimed to clarify the effect of heat-killed Enterococcus faecalis KH2 (heat-killed KH2) strain on the wound-healing process and to evaluate the therapeutic potential in chronic skin wounds. We analyzed percent wound closure, re-epithelialization, and granulation area, and cytokine and growth factor production. We found that heat-killed KH2 contributed to the acceleration of re-epithelialization and the formation of granulation tissue by inducing tumor necrosis factor-α, interleukin-6, basic fibroblast growth factor, transforming growth factor (TGF)-β1, and vascular endothelial growth factor production. In addition, heat-killed KH2 also improved wound closure, which was accompanied by the increased production of TGF-β1 in diabetic mice. Topical administration of heat-killed KH2 might have therapeutic potential for the treatment of chronic skin wounds in diabetes mellitus. In the present study, we concluded that heat-killed KH2 promoted skin wound-healing through the formation of granulation tissues and the production of inflammatory cytokines and growth factors.

Systemic inflammatory responses after orthopedic surgery in patients with rheumatoid arthritis treated with tofacitinib

OBJECTIVE

To investigate the acute phase response to surgical stress in patients with rheumatoid arthritis (RA) treated with tofacitinib, a Janus kinase (JAK) inhibitor.

METHODS

A retrospective matched pair analysis of 34 patients treated with tofacitinib and 34 patients treated with conventional disease-modifying anti-rheumatic drugs (csDMARDs) was performed. Patients were matched for age, sex, and type of surgery; body temperature, C-reactive protein (CRP) level, and white blood cell (WBC) count, neutrophil count, and lymphocyte count were compared between the tofacitinib and csDMARDs groups within 2 weeks after orthopedic surgery. Postoperative complications within 90 days were also assessed.

RESULTS

No surgical site infection or delayed wound healing was observed in the tofacitinib group; whereas, one case of superficial infection was noted in the csDMARDs group. A similar postoperative increase in body temperature and CRP level was observed in both the groups. Postoperatively, the tofacitinib group showed an increase in WBC and neutrophils counts and a decrease in lymphocyte count, unlike the csDMARDs group. In contrast to two patients (2.6%) in the csDMARDs group, seven patients (20.6%) in the tofacitinib group had lymphocyte counts below 500 cells/μL within 2 weeks postoperatively.

CONCLUSION

Tofacitinib did not suppress postoperative increase in body temperature and CRP level. Because of the postoperative decrease in lymphocyte count in patients treated with tofacitinib, the timing for resuming tofacitinib treatment after surgery should be carefully considered. Key Points • This study is the first to report the complications and systemic inflammatory responses after orthopedic surgery in patients treated with tofacitinib in comparison with matched pairs treated with conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs) • While tofacitinib does not suppress postoperative increase in body temperature and CRP level, the postoperative decrease in lymphocyte count in patients treated with tofacitinib is significant compared with patients treated with csDMARDs • Attention should be paid to a reduced lymphocyte count when to resume tofacitinib after surgery.

Fermitin family homolog 2 (Kindlin-2) affects vascularization during the wound healing process by regulating the Wnt/β-catenin signaling pathway in vascular endothelial cells

Kindlin-2 is a member of the FERM-containing cytoskeletal protein family that regulates cell–matrix interactions. Previous studies have shown that Kindlin-2 recruits focal adhesion proteins and regulates integration by binding to the focal adhesion region of the integrin β-segment. Although Kindlin-2 has been reported to be involved in various skin diseases and many kinds of tumors, its role in the skin wound healing process remains unclear. The aim of the present study was to investigate the role of Kindlin-2 in the regulation of wound healing. The effects of Kindlin-2 on wound healing were studied by a wound healing model, kindlin-2 (±) mice. The effects of Kindlin-2 on cell migration, cellular tube formation, and cell adhesion and spreading were evaluated in human umbilical vein endothelial cells (HUVECs) with downregulated Kindlin-2 expression. We found that the expression of kindlin-2 was elevated in wound healing tissues and that interfering with the expression of Kindlin-2 delayed the wound healing process and reduced neovascularization. We found that the wound healing of kindlin-2 (±) mice was delayed, with a decreased number of new blood vessels. Furthermore, depletion of Kindlin-2 impaired HUVEC spreading, migration and tube formation. Intriguingly, we found that kindlin-2 binds to β-catenin in the Wnt/β-catenin signaling pathway and cooperates with β-catenin to enter the nucleus from the cytoplasm, activating the downstream Wnt/β-catenin signaling pathway. Taken together, these results help to elucidate the mechanism of Kindlin-2 in the regulation of the wound healing process and provide a theoretical basis for further study of wound healing and abnormal healing.

Limited Treatment Options for Diabetic Wounds: Barriers to Clinical Translation Despite Therapeutic Success in Murine Models

Significance: Millions of people worldwide suffer from diabetes mellitus and its complications, including chronic diabetic wounds. To date, there are few widely successful clinical therapies specific to diabetic wounds beyond general wound care, despite the vast number of scientific discoveries in the pathogenesis of defective healing in diabetes. Recent Advances: In recent years, murine animal models of diabetes have enabled the investigation of many possible therapeutics for diabetic wound care. These include specific cell types, growth factors, cytokines, peptides, small molecules, plant extracts, microRNAs, extracellular vesicles, novel wound dressings, mechanical interventions, bioengineered materials, and more. Critical Issues: Despite many research discoveries, few have been translated from their success in murine models to clinical use in humans. This massive gap between bench discovery and bedside application begs the simple and critical question: what is still missing? The complexity and multiplicity of the diabetic wound makes it an immensely challenging therapeutic target, and this lopsided progress highlights the need for new methods to overcome the bench-to-bedside barrier. How can laboratory discoveries in animal models be effectively translated to novel clinical therapies for human patients? Future Directions: As research continues to decipher deficient healing in diabetes, new approaches and considerations are required to ensure that these discoveries can become translational, clinically usable therapies. Clinical progress requires the development of new, more accurate models of the human disease state, multifaceted investigations that address multiple critical components in wound repair, and more innovative research strategies that harness both the existing knowledge and the potential of new advances across disciplines.

Loss of Interleukin-6 Influences Transcriptional Immune Signatures and Alters Bacterial Colonization in the Skin

The skin functions as a protective barrier to inhibit the entry of foreign pathogens, all the while hosting a diverse milieu of microorganisms. Over time, skin cells, immune cells, cytokines, and microbes interact to integrate the processes of maintaining the skin's physical and immune barrier. In the present study, the basal expression of two immunologically divergent mouse strains C57BL/6 and BALB/c, as well as a strain on the C57 background lacking IL-6, was characterized. Additionally, cutaneous antimicrobial gene expression profiles and skin bacterial microbiome were assessed between strains. Total RNA sequencing was performed on untreated C57BL/6 (control), BALB/c, and IL-6-deficient skin samples and found over 3,400 genes differentially modulated between strains. It was found that each strain modulated its own transcriptional "profile" associated with skin homeostasis and also influenced the overall bacterial colonization as indicated by the differential phyla present on each strain. Together, these data not only provide a comprehensive view of the transcriptional changes in homeostatic skin of different mouse strains but also highlight the possible influence of the strain differences (e.g., Th1/Th2 balance) as well as a role for IL-6 in overall skin immunity and resident microbial populations.

Identification of potential hub genes associated with skin wound healing based on time course bioinformatic analyses

Background

The skin is the largest organ of the body and has multiple functions. Wounds remain a significant healthcare problem due to the large number of traumatic and pathophysiological conditions patients suffer.

Methods

Gene expression profiles of 37 biopsies collected from patients undergoing split-thickness skin grafts at five different time points were downloaded from two datasets (GSE28914 and GSE50425) in the Gene Expression Omnibus (GEO) database. Principal component analysis (PCA) was applied to classify samples into different phases. Subsequently, differentially expressed genes (DEGs) analysis, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway functional enrichment analyses were performed, and protein–protein interaction (PPI) networks created for each phase. Furthermore, based on the results of the PPI, hub genes in each phase were identified by molecular complex detection combined with the ClueGO algorithm.

Results

Using principal component analysis, the collected samples were divided into four phases, namely intact phase, acute wound phase, inflammatory and proliferation phase, and remodeling phase. Intact samples were used as control group. In the acute wound phase, a total of 1 upregulated and 100 downregulated DEGs were identified. Tyrosinase (TYR), tyrosinase Related Protein 1 (TYRP1) and dopachrome tautomerase (DCT) were considered as hub genes and enriched in tyrosine metabolism which dominate the process of melanogenesis. In the inflammatory and proliferation phase, a total of 85 upregulated and 164 downregulated DEGs were identified. CHEK1, CCNB1 and CDK1 were considered as hub genes and enriched in cell cycle and P53 signaling pathway. In the remodeling phase, a total of 121 upregulated and 49 downregulated DEGs were identified. COL4A1, COL4A2, and COL6A1 were considered as hub genes and enriched in protein digestion and absorption, and ECM-receptor interaction.

Conclusion

This comprehensive bioinformatic re-analysis of GEO data provides new insights into the molecular pathogenesis of wound healing and the potential identification of therapeutic targets for the treatment of wounds.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-021-01298-w.

Effect of Subcutaneous Topical Ozone Therapy on Second-Degree Burn Wounds in Rats: An Experimental Study

Burns are one of the most severe traumas, causing coagulative destruction of the skin. The use of various products that accelerate wound healing in patients with burns may affect rates of patient survival and reduce complications. We studied the effects of subcutaneous ozone injection on second-degree burn wounds in animal model. For this study, 72 Sprague-Dawley male rats were divided randomly into the following three groups: control group , silver sulfadiazine group, and ozone group; each group was then divided randomly into two subgroups (day 7 or day 14 examination and sacrifice). Superficial partial thickness burns were created on the lower back. In the control group, subcutaneous 0.9% serum saline was injected daily into the burn area. In the silver sulfadiazine group, burns were dressed daily with silver sulfadiazine. In the ozone group, subcutaneous ozone was injected daily into the burn area. We performed tissue hydroxyproline level measurements and histopathological evaluations. When groups were compared in terms of weight change, no significant difference was found between day 7 and day 14. With regard to tissue hydroxyproline levels the ozone group had significantly higher levels on both day 7 and day 14 (P < .001). In histopathological evaluations, we determined that wound healing in the ozone group was significantly higher than in the other groups. We found that subcutaneous ozone therapy was more effective than silver sulfadiazine in the healing process of second-degree burn wounds and could be safely used in the treatment of burn wounds.

A cut above the rest: oxidative stress in chronic wounds and the potential role of polyphenols as therapeutics

OBJECTIVES

The pathophysiology of chronic wounds typically involves redox imbalance and inflammation pathway dysregulation, often with concomitant microbial infection. Endogenous antioxidants such as glutathione and tocopherols are notably reduced or absent, indicative of significant oxidative imbalance. However, emerging evidence suggests that polyphenols could be effective agents for the amelioration of this condition. This review aims to summarise the current state of knowledge surrounding redox imbalance in the chronic wound environment and the potential use of polyphenols for the treatment of chronic wounds.

KEY FINDINGS

Polyphenols provide a multi-faceted approach towards the treatment of chronic wounds. Firstly, their antioxidant activity allows direct neutralisation of harmful free radicals and reactive oxygen species, assisting in restoring redox balance. Upregulation of pro-healing and anti-inflammatory gene pathways and enzymes by specific polyphenols further acts to reduce redox imbalance and promote wound healing actions, such as proliferation, extracellular matrix deposition and tissue remodelling. Finally, many polyphenols possess antimicrobial activity, which can be beneficial for preventing or resolving infection of the wound site.

SUMMARY

Exploration of this diverse group of natural compounds may yield effective and economical options for the prevention or treatment of chronic wounds.

CaMKIIδ is upregulated by pro-inflammatory cytokine IL-6 in a JAK/STAT3-dependent manner to promote angiogenesis

Ca²⁺ /calmodulin-dependent protein kinase II (CaMKII) is a ubiquitous serine threonine kinase with established roles in physiological and pathophysiological vascular remodeling. Based on our previous study demonstrating that CaMKIIδ promotes thrombin-induced endothelial permeability and recent reports that CaMKII may contribute to inflammatory remodeling in the heart, we investigated CaMKIIδ-dependent regulation of endothelial function downstream of an interleukin-6 (IL-6)/JAK/STAT3 signaling axis. Upon treatment with IL-6 and its soluble receptor (sIL-6r), CaMKIIδ expression is significantly induced in HUVEC. Using pharmacological inhibitors of JAK and siRNA targeting STAT3, we demonstrated that activation of STAT3 is sufficient to induce CaMKIIδ expression. Under these conditions, rather than promoting IL-6-induced permeability, we found that CaMKIIδ promotes endothelial cell migration as measured by live cell imaging of scratch wound closure and single-cell motility analysis. In a similar manner, endothelial cell proliferation was attenuated upon knockdown of CaMKIIδ as determined by growth curves, cell cycle analysis, and capacitance of cell-covered electrodes as measured by ECIS. Using inducible endothelial-specific STAT3 knockout mice, we demonstrate that STAT3 signaling promotes developmental angiogenesis in the neonatal mouse retina assessed at postnatal day 6. CaMKIIδ expression in retinal endothelium was attenuated in these animals as measured by qPCR. STAT3's effects on angiogenesis were phenocopied by the endothelial-specific knockout of CaMKIIδ, with significantly reduced vascular outgrowth and number of junctions in the developing P6 retina. For the first time, we demonstrate that transcriptional regulation of CaMKIIδ by STAT3 promotes endothelial motility, proliferation, and in vivo angiogenesis.

Systemic and topical administration of spermidine accelerates skin wound healing

BACKGROUND

The skin wound healing process is regulated by various cytokines, chemokines, and growth factors. Recent reports have demonstrated that spermine/spermidine (SPD) promote wound healing through urokinase-type plasminogen activator (uPA)/uPA receptor (uPAR) signaling in vitro. Here, we investigated whether the systemic and topical administration of SPD would accelerate the skin wound-repair process in vivo.

METHODS

A skin wound repair model was established using C57BL/6 J mice. SPD was mixed with white petrolatum for topical administration. For systemic administration, SPD mixed with drinking water was orally administered. Changes in wound size over time were calculated using digital photography.

RESULTS

Systemic and topical SPD treatment significantly accelerated skin wound healing. The administration of SPD promoted the uPA/uPAR pathway in wound sites. Moreover, topical treatment with SPD enhanced the expression of IL-6 and TNF-α in wound sites. Scratch and cell proliferation assays revealed that SPD administration accelerated scratch wound closure and cell proliferation in vitro.

CONCLUSION

These results indicate that treatment with SPD promotes skin wound healing through activation of the uPA/uPAR pathway and induction of the inflammatory response in wound sites. The administration of SPD might contribute to new effective treatments to accelerate skin wound healing. Video Abstract.

Effect of bovine bone collagen oligopeptides on wound healing in mice

Impaired wound healing often brings a set of problems in clinical practice. This study aimed to observe the wound healing potential of bovine bone collagen oligopeptides (BCOP) in mice. After an operation, mice in BCOP-treated groups were given intragastric administration of BCOP, while others were administered vehicle. Mice were sacrificed at different points. The wound healing condition and the tensile strength were observed, serum biochemical indexes and mRNA expression of level of related genes were measured. Compared with the normal control group, albumin (ALB), prealbumin (PA), transferrin (TRF), hydroxyproline (Hyp) levels and tension strength in the BCOP-treated groups increased significantly (p < 0.05). A pathological report showed that neutrophil granulocyte in the BCOP-treated groups decreased, while blood capillary and fibroblasts increased. The levels of serum inflammation indexes like interleukin (IL)-8, tumor necrosis factor (TNF)-α, chemokine (C-C motif) ligand 2 (CCL2) and C-reactive protein (CRP) significantly decreased in full-thickness incision model, whereas increased in full-thickness excision model (p < 0.05). Furthermore, IL-10, stromal cell-derived factor-1 alpha (SDF-1α) levels and the mRNA expression of vascular endothelial growth factor (VEGF) significantly increased in both models (p < 0.05). These results suggested that oral administration of BCOP could promote wound healing in mice.

Inhibitory effects of curcumin against cytotoxicity of Porphyromonas gingivalis outer membrane vesicles

OBJECTIVE

The purpose of this study was to examine whether curcumin, a turmeric root extract, protects human gingival epithelial (HGE) cells from the cytotoxic effects ofPorphyromonas gingivalis outer membrane vesicles (OMVs).

DESIGN

OMVs were prepared fromP. gingivalis OMZ314 and used to stimulate human gingival epithelial (HGE) cells. The effects of curcumin on cellular expression of inflammatory cytokines were evaluated using real-time reverse transcription-polymerase chain reaction assays, while those on cellular migration were examined with a scratch wound assay. Furthermore, HGE cells were incubated with OMVs in the presence or absence of curcumin, then intracellular invasion by OMVs was observed with confocal laser scanning microscopy. Also, the effects of curcumin on cellular apoptotic death was examined.

RESULTS

Gene expressions of IL-6, IL-1β, and TNF-α in HGE cells stimulated with OMVs were significantly suppressed by curcumin in a dose-dependent manner, with suppressed protein production also noted. Moreover, curcumin inhibited the cytotoxic effects of OMVs on cellular migration. Finally, curcumin inhibited OMV adherence to and entry of cells, as well as cellular apoptotic death in a dose-dependent manner.

CONCLUSIONS

Curcumin showed marked inhibitory effects against the cytotoxic actions of P. gingivalis OMVs, indicating possible potency for preventing periodontal disease.

Inhibition of persimmon tannin extract on guinea pig skin pigmentation

BACKGROUND

In daily life, excessive exposure to ultraviolet light can lead to pigmentation.

AIMS

This study is to determine the mechanism of persimmon tannin extract in inhibiting pigmentation, to investigate whether the effect of persimmon tannin extract is superior to that of arbutin, and to detect the optimal concentration.

METHODS

In this study, the guinea pig pigmentation model was established by ultraviolet B (UVB) irradiation. With arbutin as a positive control, Masson-Fontana silver staining was used to observe the effects of persimmon tannin extract on melanin distribution in guinea pigs' skin tissue. Then, the tyrosinase activity was measured, and an Enzyme-linked immunosorbent assay was used to investigate the contents of antioxidant enzymes, inflammatory factors, and signaling pathway inhibitors in guinea pigs' skin tissue.

RESULTS

The results showed that compared with the model group, superoxide dismutase, catalase, glutathione peroxidase, DKK1 content of Wnt/-catenin signaling pathway inhibitors levels, and inhibitory tyrosinase activity were increased by 24.3%, 33.3%, 59.3%, 36.81%, and 17.16%, respectively. Meanwhile, the interleukin-6 and interleukin-8 expression were reduced by approximately 22.2% and 54%. The results also showed that persimmon tannin extract could significantly reduce melanin density. The differences in experimental results were statistically significant (P < .01).

CONCLUSIONS

Compared with the arbutin group, the medium-dose group (persimmon tannin extract of 20%) had a more significant effect on inhibiting pigmentation. Persimmon tannin could serve as a promising agent for preventing skin pigmentation. It is expected to provide ideas for the development of deep-processed persimmon products related to functional foods and cosmetics.

Repair function of essential oil from Crocodylus Siamensis (Schneider, 1801) on the burn wound healing via up-regulated growth factor expression and anti-inflammatory effect

ETHNOPHARMACOLOGICAL RELEVANCE

Crocodile oil has been used by traditional physicians around the world to treat wound healing and inflammation. However, the scientific rationale and mechanism behind its use in vivo has not been fully researched.

AIMS OF THE STUDY

We mainly investigated the mechanism during crocodile oil treatment of up-regulated growth factor expression and anti-inflammatory on burn wound healing in rats.

MATERIALS AND METHODS

The moisture and nitric oxide (NO) levels in the skin of rats were analyzed in the first 14 days after burn and the changes of the structure of the skin tissues in the wound healing were studied by hematoxylin-eosin (H.E.) staining within 21 days after scald. The inflammatory factor on burn wound healing in rats was dected by ELISA kits and Q-PCR. the expression of a variety of growth factors (TGF-β1, VEGE-α, EGF) and PCNA in the skin tissue after burns was evaluated using immunohistochemistry. The down-regulated phosphorylation of p38 MAPK in the wound healing was confirmed by Western-blot analysis. In addition, TEM was used to observe the ultrastructure of scalded skin.

RESULTS

This study showed that crocodile oil could significantly reduce the protein and mRNA levels of TNF-α, IL-1β and IL-6. And it was found that the phosphorylation of p38 MAPK was down-regulated in the wound healing (p < 0.05). Meanwhile, crocodile oil can promote the expression of a variety of growth factors (TGF-β1, VEGE-α, EGF) and PCNA in the skin tissue after burns, and promote the repair of collagen fibers in the dermis, preventing the production of melanin and maintain the appearance of repaired skin.

Characterisation of baseline microbiological and host factors in an inception cohort of people with surgical wounds healing by secondary intention reveals circulating IL-6 levels as a potential predictive biomarker of healing

Background: More than 2 million people per year are treated for surgical wounds in the UK.  Over a quarter of these wounds are estimated to heal by secondary intention (from the "bottom up") resulting in further complications and requiring increased healthcare resources. Identification of microbiological or host biomarkers that can predict healing outcomes may help to optimize the management of surgical wounds healing by secondary intention. However, the microbial and host factor heterogeneity amongst this diverse population is completely unexplored. Methods: We demonstrate feasibility of determining presence and levels of wound microbes and systemic host factors in an inception cohort of 54 people presenting with surgical wounds healing by secondary intention, who were subsequently followed-up for a period of 12-21 months. We present descriptive statistics for plasma levels of inflammatory, angiogenic cytokines and microRNAs, and we identify a range of wound colonizing microbes. We tentatively explore association with healing aiming to generate hypotheses for future research. Results: We report a potential correlation between poor healing outcomes and elevated interleukin (IL)-6 plasma levels at presentation (ρ=0.13) which requires confirmation.   Conclusions: This study demonstrates the degree of biological heterogeneity amongst people with surgical wounds healing by secondary intention and proves the feasibility of embedding a biomarker discovery study in a cohort study in surgical wounds. Our results are essential for designing large biomarker discovery studies to further investigate the potential validity of circulating IL-6 or other factors as novel predictive biomarkers of healing for surgical wounds healing by secondary intention.

Pleiotropic actions of Vitamin D in composite musculoskeletal trauma

Composite tissue injuries are the result of high energy impacts caused by motor vehicle accidents, gunshot wounds or blasts. These are highly traumatic injuries characterized by wide-spread, penetrating wounds affecting the entire musculoskeletal system, and are generally defined by frank volumetric muscle loss with concomitant segmental bone defects. At the tissue level, the breadth of damage to multiple tissue systems, and potential for infection from penetration, have been shown to lead to an exaggerated, often chronic inflammatory response with subsequent dysregulation of normal musculoskeletal healing mechanisms. Aside from the direct effects of inflammation on myogenesis and osteogenesis, frank muscle loss has been shown to directly impair fracture union and ultimately contribute to failed wound regeneration. Care for these injuries requires extensive surgical intervention and acute care strategies. However, often these interventions do not adequately mitigate inflammation or promote proper musculoskeletal injury repair and force amputation of the limb. Therefore, identification of factors that can promote tissue regeneration and mitigate inflammation could be key to restoring wound healing after composite tissue injury. One such factor that may directly affect both inflammation and tissue regeneration in response to these multi-tissue injuries may be Vitamin D. Beyond traditional roles, the pleiotropic and localized actions of Vitamin D are increasingly being recognized in most aspects of wound healing in complex tissue injuries - e.g., regulation of inflammation, myogenesis, fracture callus mineralization and remodeling. Conversely, pre-existing Vitamin D deficiency leads to musculoskeletal dysfunction, increased fracture risk or fracture non-unions, decreased strength/function and reduced capacity to heal wounds through increased inflammation. This Vitamin D deficient state requires acute supplementation in order to quickly restore circulating levels to an optimal level, thereby facilitating a robust wound healing response. Herein, the purpose of this review is to address the roles and critical functions of Vitamin D throughout the wound healing process. Findings from this review suggest that careful monitoring and/or supplementation of Vitamin D may be critical for wound regeneration in composite tissue injuries.

Deregulated immune cell recruitment orchestrated by FOXM1 impairs human diabetic wound healing

Diabetic foot ulcers (DFUs) are a life-threatening disease that often result in lower limb amputations and a shortened lifespan. However, molecular mechanisms contributing to the pathogenesis of DFUs remain poorly understood. We use next-generation sequencing to generate a human dataset of pathogenic DFUs to compare to transcriptional profiles of human skin and oral acute wounds, oral as a model of “ideal” adult tissue repair due to accelerated closure without scarring. Here we identify major transcriptional networks deregulated in DFUs that result in decreased neutrophils and macrophages recruitment and overall poorly controlled inflammatory response. Transcription factors FOXM1 and STAT3, which function to activate and promote survival of immune cells, are inhibited in DFUs. Moreover, inhibition of FOXM1 in diabetic mouse models (STZ-induced and db/db) results in delayed wound healing and decreased neutrophil and macrophage recruitment in diabetic wounds in vivo. Our data underscore the role of a perturbed, ineffective inflammatory response as a major contributor to the pathogenesis of DFUs, which is facilitated by FOXM1-mediated deregulation of recruitment of neutrophils and macrophages, revealing a potential therapeutic strategy.

Diabetic foot ulcers (DFU) represent a complex disease with limited treatment options. Here, the authors compare human RNASeq patient data from DFU, oral mucosa and skin acute wounds, identifying FOXM1 as a mediator of macrophage and neutrophil recruitment, which contributes to disease pathogenesis and is dysregulated in patients.