Chemokines and Their Receptors Are Key Players in the Orchestra That Regulates Wound Healing

Wound Bed Preparation and Treatment Modalities

Wound healing is a highly complex natural process, and its failure results in chronic wounds. The causes of delayed wound healing include patient-related and local wound factors. The main local impediments to delayed healing are the presence of nonviable tissue, excessive inflammation, infection, and moisture imbalance. For wounds that can be healed with adequate blood supply, a stepwise approach to identify and treat these barriers is termed wound bed preparation. Currently, a combination of patient-related and local factors, including wound debridement, specialty dressings, and advanced technologies, is available and successfully used to facilitate the healing process.

Human platelet lysate-cultured adipose-derived stem cell sheets promote angiogenesis and accelerate wound healing via CCL5 modulation

BACKGROUND

A rising population faces challenges with healing-impaired cutaneous wounds, often leading to physical disabilities. Adipose-derived stem cells (ASCs), specifically in the cell sheet format, have emerged as a promising remedy for impaired wound healing. Human platelet lysate (HPL) provides an attractive alternative to fetal bovine serum (FBS) for culturing clinical-grade ASCs. However, the potential of HPL sheets in promoting wound healing has not been fully investigated. This study aimed to explore the anti-fibrotic and pro-angiogenic capabilities of HPL-cultured ASC sheets and delve into the molecular mechanism.

METHODS

A rat burn model was utilized to evaluate the efficacy of HPL-cultured ASC sheets in promoting wound healing. ASC sheets were fabricated with HPL, and those with FBS were included for comparison. Various analyses were conducted to assess the impact of HPL sheets on wound healing. Histological examination of wound tissues provided insights into aspects such as wound closure, collagen deposition, and overall tissue regeneration. Immunofluorescence was employed to assess the presence and distribution of transplanted ASCs after treatment. Further in vitro studies were conducted to decipher the specific factors in HPL sheets contributing to angiogenesis.

RESULTS

HPL-cultured ASC sheets significantly accelerated wound closure, fostering ample and organized collagen deposition in the neo-dermis. Significantly more retained ASCs were observed in wound tissues treated with HPL sheets compared to the FBS counterparts. Moreover, HPL sheets mitigated macrophage recruitment and decreased subsequent wound tissue fibrosis in vivo. Immunohistochemistry also indicated enhanced angiogenesis in the HPL sheet group. The in vitro analyses showed upregulation of C-C motif chemokine ligand 5 (CCL5) and angiogenin in HPL sheets, including both gene expression and protein secretion. Culturing endothelial cells in the conditioned media compared to media supplemented with CCL5 or angiogenin suggested a correlation between CCL5 and the pro-angiogenic effect of HPL sheets. Additionally, through neutralizing antibody experiments, we further validated the crucial role of CCL5 in HPL sheet-mediated angiogenesis in vitro.

CONCLUSIONS

The present study underscores CCL5 as an essential factor in the pro-angiogenic effect of HPL-cultured ASC sheets during the wound healing process. These findings highlight the potential of HPL-cultured ASC sheets as a promising therapeutic option for healing-impaired cutaneous wounds in clinical settings. Furthermore, the mechanism exploration yields valuable information for optimizing regenerative strategies with ASC products.

BRIEF ACKNOWLEDGMENT

This research was supported by the National Science and Technology Council, Taiwan (NSTC112-2321-B-002-018), National Taiwan University Hospital (111C-007), and E-Da Hospital-National Taiwan University Hospital Joint Research Program (111-EDN0001, 112-EDN0002).

Recent advances in molecular mechanisms of skin wound healing and its treatments

The skin, being a multifaceted organ, performs a pivotal function in the complicated wound-healing procedure, which encompasses the triggering of several cellular entities and signaling cascades. Aberrations in the typical healing process of wounds may result in atypical scar development and the establishment of a persistent condition, rendering patients more vulnerable to infections. Chronic burns and wounds have a detrimental effect on the overall quality of life of patients, resulting in higher levels of physical discomfort and socio-economic complexities. The occurrence and frequency of prolonged wounds are on the rise as a result of aging people, hence contributing to escalated expenditures within the healthcare system. The clinical evaluation and treatment of chronic wounds continue to pose challenges despite the advancement of different therapeutic approaches. This is mainly owing to the prolonged treatment duration and intricate processes involved in wound healing. Many conventional methods, such as the administration of growth factors, the use of wound dressings, and the application of skin grafts, are used to ease the process of wound healing across diverse wound types. Nevertheless, these therapeutic approaches may only be practical for some wounds, highlighting the need to advance alternative treatment modalities. Novel wound care technologies, such as nanotherapeutics, stem cell treatment, and 3D bioprinting, aim to improve therapeutic efficacy, prioritize skin regeneration, and minimize adverse effects. This review provides an updated overview of recent advancements in chronic wound healing and therapeutic management using innovative approaches.

Role of the Skin Immune System in Wound Healing

Wound healing is a dynamic and complex process, characterized by the coordinated activities of multiple cell types, each with distinct roles in the stages of hemostasis, inflammation, proliferation, and remodeling. The cells of the immune system not only act as sentinels to monitor the skin and promote homeostasis, but they also play an important role in the process of skin wound repair. Skin-resident and recruited immune cells release cytokines and growth factors that promote the amplification of the inflammatory process. They also work with non-immune cells to remove invading pathogens and debris, as well as guide the regeneration of damaged host tissues. Dysregulation of the immune system at any stage of the process may lead to a prolongation of the inflammatory phase and the development of a pathological condition, such as a chronic wound. The present review aims to summarize the roles of different immune cells, with special emphasis on the different stages of the wound healing process.

Advancements in Regenerative Hydrogels in Skin Wound Treatment: A Comprehensive Review

This state-of-the-art review explores the emerging field of regenerative hydrogels and their profound impact on the treatment of skin wounds. Regenerative hydrogels, composed mainly of water-absorbing polymers, have garnered attention in wound healing, particularly for skin wounds. Their unique properties make them well suited for tissue regeneration. Notable benefits include excellent water retention, creating a crucially moist wound environment for optimal healing, and facilitating cell migration, and proliferation. Biocompatibility is a key feature, minimizing adverse reactions and promoting the natural healing process. Acting as a supportive scaffold for cell growth, hydrogels mimic the extracellular matrix, aiding the attachment and proliferation of cells like fibroblasts and keratinocytes. Engineered for controlled drug release, hydrogels enhance wound healing by promoting angiogenesis, reducing inflammation, and preventing infection. The demonstrated acceleration of the wound healing process, particularly beneficial for chronic or impaired healing wounds, adds to their appeal. Easy application and conformity to various wound shapes make hydrogels practical, including in irregular or challenging areas. Scar minimization through tissue regeneration is crucial, especially in cosmetic and functional regions. Hydrogels contribute to pain management by creating a protective barrier, reducing friction, and fostering a soothing environment. Some hydrogels, with inherent antimicrobial properties, aid in infection prevention, which is a crucial aspect of successful wound healing. Their flexibility and ability to conform to wound contours ensure optimal tissue contact, enhancing overall treatment effectiveness. In summary, regenerative hydrogels present a promising approach for improving skin wound healing outcomes across diverse clinical scenarios. This review provides a comprehensive analysis of the benefits, mechanisms, and challenges associated with the use of regenerative hydrogels in the treatment of skin wounds. In this review, the authors likely delve into the application of rational design principles to enhance the efficacy and performance of hydrogels in promoting wound healing. Through an exploration of various methodologies and approaches, this paper is poised to highlight how these principles have been instrumental in refining the design of hydrogels, potentially revolutionizing their therapeutic potential in addressing skin wounds. By synthesizing current knowledge and highlighting potential avenues for future research, this review aims to contribute to the advancement of regenerative medicine and ultimately improve clinical outcomes for patients with skin wounds.

Immunomodulatory hydrogels for skin wound healing: cellular targets and design strategy

Skin wounds significantly impact the global health care system and represent a significant burden on the economy and society due to their complicated dynamic healing processes, wherein a series of immune events are required to coordinate normal and sequential healing phases, involving multiple immunoregulatory cells such as neutrophils, macrophages, keratinocytes, and fibroblasts, since dysfunction of these cells may impede skin wound healing presenting persisting inflammation, impaired vascularization, and excessive collagen deposition. Therefore, cellular target-based immunomodulation is promising to promote wound healing as cells are the smallest unit of life in immune response. Recently, immunomodulatory hydrogels have become an attractive avenue to promote skin wound healing. However, a detailed and comprehensive review of cellular targets and related hydrogel design strategies remains lacking. In this review, the roles of the main immunoregulatory cells participating in skin wound healing are first discussed, and then we highlight the cellular targets and state-of-the-art design strategies for immunomodulatory hydrogels based on immunoregulatory cells that cover defect, infected, diabetic, burn and tumor wounds and related scar healing. Finally, we discuss the barriers that need to be addressed and future prospects to boost the development and prosperity of immunomodulatory hydrogels.

Cytokine, chemokine alterations and immune cell infiltration in Radiation-induced lung injury: Implications for prevention and management

Radiation therapy is one of the primary treatments for thoracic malignancies, with radiation-induced lung injury (RILI) emerging as its most prevalent complication. RILI encompasses early-stage radiation pneumonitis (RP) and the subsequent development of radiation pulmonary fibrosis (RPF). During radiation treatment, not only are tumor cells targeted, but normal tissue cells, including alveolar epithelial cells and vascular endothelial cells, also sustain damage. Within the lungs, ionizing radiation boosts the intracellular levels of reactive oxygen species across various cell types. This elevation precipitates the release of cytokines and chemokines, coupled with the infiltration of inflammatory cells, culminating in the onset of RP. This pulmonary inflammatory response can persist, spanning a duration from several months to years, ultimately progressing to RPF. This review aims to explore the alterations in cytokine and chemokine release and the influx of immune cells post-ionizing radiation exposure in the lungs, offering insights for the prevention and management of RILI.

The cell stress and immunity cycle in cancer: Toward next generation of cancer immunotherapy

The cellular stress and immunity cycle is a cornerstone of organismal homeostasis. Stress activates intracellular and intercellular communications within a tissue or organ to initiate adaptive responses aiming to resolve the origin of this stress. If such local measures are unable to ameliorate this stress, then intercellular communications expand toward immune activation with the aim of recruiting immune cells to effectively resolve the situation while executing tissue repair to ameliorate any damage and facilitate homeostasis. This cellular stress-immunity cycle is severely dysregulated in diseased contexts like cancer. On one hand, cancer cells dysregulate the normal cellular stress responses to reorient them toward upholding growth at all costs, even at the expense of organismal integrity and homeostasis. On the other hand, the tumors severely dysregulate or inhibit various components of organismal immunity, for example, by facilitating immunosuppressive tumor landscape, lowering antigenicity, and increasing T-cell dysfunction. In this review we aim to comprehensively discuss the basis behind tumoral dysregulation of cellular stress-immunity cycle. We also offer insights into current understanding of the regulators and deregulators of this cycle and how they can be targeted for conceptualizing successful cancer immunotherapy regimen.

Chemokine- and chemokine receptor-based signature predicts immunotherapy response in female colorectal adenocarcinoma patients

The clinical significance and comprehensive characteristics of chemokines and chemokine receptors in female patients with advanced colorectal adenocarcinoma have not ever been reported. Our study explored the expression profiles of chemokines and chemokine receptors and constructed a chemokine- and chemokine receptor-based signature in female patients with advanced colorectal adenocarcinoma. Four independent cohorts containing 1335 patients were enrolled in our study. Univariate Cox regression and least absolute shrinkage and selection operator (LASSO) analyses were performed to construct the signature. CIBERSORT was used to evaluate the landscape of immune cell infiltration. Thirty-two pairs of tissue specimens of female advanced colorectal cancer (CRC) patients and two CRC cell lines were used to validate the signature in vitro. Quantitative real-time PCR and western blotting were performed to validate the mRNA and protein expression levels of signature genes. EdU and colony formation assays were performed to examine proliferative ability. Transwell and wound healing assays were used to evaluate cell invasion and migration capacity. During the signature construction and validation process, we found that the signature was more applicable to female patients with advanced colorectal adenocarcinoma. Hence, the subsequent study mainly focused on the particular subgroup. Enrichment analyses revealed that the signature was closely related to immunity. The landscape of immune cell infiltration presented that the signature was significantly associated with T cells CD8 and neutrophils. Gene set enrichment analysis (GSEA) confirmed that the high-risk group was chiefly enriched in the tumor-promoting related pathways and biological processes, whereas the low-risk group was mainly enriched in anti-tumor immune response pathways and biological processes. The signature was closely correlated with CTLA4, PDL1, PDL2, TMB, MSI, and TIDE, indicating that our signature could serve as a robust biomarker for immunotherapy and chemotherapy response. ROC curves verified that our signature had more robust prognostic power than all immune checkpoints and immunotherapy-related biomarkers. Finally, we used 32 pairs of tissue specimens and 2 CRC cell lines to validate our signature in vitro. We first provided a robust prognostic chemokine- and chemokine receptor-based signature, which could serve as a novel biomarker for immunotherapy and chemotherapy response to guide individualized treatment for female patients with advanced colorectal adenocarcinoma.

Multifunctional and theranostic hydrogels for wound healing acceleration: An emphasis on diabetic-related chronic wounds

Hydrogels represent intricate three-dimensional polymeric structures, renowned for their compatibility with living systems and their ability to naturally degrade. These networks stand as promising and viable foundations for a range of biomedical uses. The practical feasibility of employing hydrogels in clinical trials has been well-demonstrated. Among the prevalent biomedical uses of hydrogels, a significant application arises in the context of wound healing. This intricate progression involves distinct phases of inflammation, proliferation, and remodeling, often triggered by trauma, skin injuries, and various diseases. Metabolic conditions like diabetes have the potential to give rise to persistent wounds, leading to delayed healing processes. This current review consolidates a collection of experiments focused on the utilization of hydrogels to expedite the recovery of wounds. Hydrogels have the capacity to improve the inflammatory conditions at the wound site, and they achieve this by diminishing levels of reactive oxygen species (ROS), thereby exhibiting antioxidant effects. Hydrogels have the potential to enhance the growth of fibroblasts and keratinocytes at the wound site. They also possess the capability to inhibit both Gram-positive and Gram-negative bacteria, effectively managing wounds infected by drug-resistant bacteria. Hydrogels can trigger angiogenesis and neovascularization processes, while also promoting the M2 polarization of macrophages, which in turn mitigates inflammation at the wound site. Intelligent and versatile hydrogels, encompassing features such as pH sensitivity, reactivity to reactive oxygen species (ROS), and responsiveness to light and temperature, have proven advantageous in expediting wound healing. Furthermore, hydrogels synthesized using environmentally friendly methods, characterized by high levels of biocompatibility and biodegradability, hold the potential for enhancing the wound healing process. Hydrogels can facilitate the controlled discharge of bioactive substances. More recently, there has been progress in the creation of conductive hydrogels, which, when subjected to electrical stimulation, contribute to the enhancement of wound healing. Diabetes mellitus, a metabolic disorder, leads to a slowdown in the wound healing process, often resulting in the formation of persistent wounds. Hydrogels have the capability to expedite the healing of diabetic wounds, facilitating the transition from the inflammatory phase to the proliferative stage. The current review sheds light on the biological functionalities of hydrogels, encompassing their role in modulating diverse mechanisms and cell types, including inflammation, oxidative stress, macrophages, and bacteriology. Additionally, this review emphasizes the significance of smart hydrogels with responsiveness to external stimuli, as well as conductive hydrogels for promoting wound healing. Lastly, the discussion delves into the advancement of environmentally friendly hydrogels with high biocompatibility, aimed at accelerating the wound healing process.

Mechanisms of resveratrol against diabetic wound by network pharmacology and experimental validation

BACKGROUND

Resveratrol (RSV) that possesses anti-oxidative, anti-inflammatory, and pro-angiogenic effects is an effective drug for diabetic wound (DW), while its pharmacological mechanism remains to be elucidated. In this study, we apply network pharmacology and experimental validation approach to reveal the potential mechanism of RSV against DW.

METHODS

We obtained potential targets for RSV and DW from the publicly available database. Using interaction networks and conducting GO and KEGG pathway enrichment analyses, we constructed target-pathway networks to explore the relationship between RSV and DW. To validate the pharmacological mechanism of RSV, we induced the DW model.

RESULTS

Ninety overlapped targets between RSV and DW were obtained, and the hub genes of the PPI network included TNF, IL-6, CASP3, MAPK3, VEGFA, IL-1β, AKT1, and JUN. Based on target-pathway networks, the AGE-RAGE signalling pathway was involved in the RSV treatment of DW. Furthermore, in vivo experiments revealed that RSV significantly promoted wound healing in diabetic mice and attenuated the expression of pro-inflammatory cytokines in wound tissue. Meanwhile, RSV could inhibit the AGE-RAGE signalling pathway and thus reduce the activation of NF-κB.

CONCLUSION

This study initially revealed the biological mechanism of RSV for treating DW through multi-target and multi-pathway. AGE-RAGE, FoxO, MAPK, PI3K-AKT and other signalling pathways may be the main pathways of RSV in treating DW. RSV reduces the inflammatory response by inhibiting the AGE-RAGE signalling pathway, which in turn promotes DW healing.

Tunable Sulfated Alginate-based Hydrogel Platform with enhanced anti-inflammatory and antioxidant capacity for promoting burn wound repair

Amidst progressive advancements in tissue engineering, there has been a significant enhancement in the efficacy of anti-inflammatory hydrogel dressings, addressing a myriad of clinical challenges on wound healing. A frequent complication during the initial stages of deep second-degree burn wound healing is the onset of an inflammatory storm, typically occurring without effective intervention. This event disrupts normal biological healing sequences, leading to undesirable regression. In response, we have customized a tunable, multidimensional anti-inflammatory hydrogel platform based on sulfated alginates (Algs), loaded with Prussian blue (PB) nanozymes. This platform competently eliminates surplus reactive oxygen species (ROS) present in the wound bed. Algs, functioning as a mimic of sulfated glycosaminoglycans (including heparin, heparan sulfate, and chondroitin sulfate) in the extracellular matrices (ECM), demonstrate a high affinity towards inflammatory chemokines such as interleukin-8 (IL-8) and monocyte chemotactic protein-1 (MCP-1). This affinity effectively impedes the infiltration of inflammatory cells into the wound. Concurrently, Algs markedly modulate the macrophage phenotype transition from M1 to M2. Ultimately, our potent anti-inflammatory hydrogels, which strategically target inflammatory chemokines, M1 macrophages, and ROS, successfully attenuate dysregulated hyperinflammation in wound sites. Precise immunomodulation administered to deep second-degree burn wounds in mice has demonstrated promotion of neovascular maturation, granulation tissue formation, collagen deposition, and wound closure. Our biomimetic hydrogels, therefore, represent a significant expansion in the repertoire of anti-inflammatory strategies available for clinical practice.

Regenerative potential of mesenchymal stromal cells in wound healing: unveiling the influence of normoxic and hypoxic environments

The innate and adaptive immune systems rely on the skin for various purposes, serving as the primary defense against harmful environmental elements. However, skin lesions may lead to undesirable consequences such as scarring, accelerated skin aging, functional impairment, and psychological effects over time. The rising popularity of mesenchymal stromal cells (MSCs) for skin wound treatment is due to their potential as a promising therapeutic option. MSCs offer advantages in terms of differentiation capacity, accessibility, low immunogenicity, and their central role in natural wound-healing processes. To accelerate the healing process, MSCs promote cell migration, angiogenesis, epithelialization, and granulation tissue development. Oxygen plays a critical role in the formation and expansion of mammalian cells. The term "normoxia" refers to the usual oxygen levels, defined at 20.21 percent oxygen (160 mm of mercury), while "hypoxia" denotes oxygen levels of 2.91 percent or less. Notably, the ambient O2 content (20%) in the lab significantly differs from the 2%-9% O2 concentration in their natural habitat. Oxygen regulation of hypoxia-inducible factor-1 (HIF-1) mediated expression of multiple genes plays a crucial role in sustaining stem cell destiny concerning proliferation and differentiation. This study aims to elucidate the impact of normoxia and hypoxia on MSC biology and draw comparisons between the two. The findings suggest that expanding MSC-based regenerative treatments in a hypoxic environment can enhance their growth kinetics, genetic stability, and expression of chemokine receptors, ultimately increasing their effectiveness.

The synovial environment steers cartilage deterioration and regeneration

Osteoarthritis (OA) was recently defined as an epidemic, and the lack of effective treatment is highly correlated to the limited knowledge regarding the underlying pathophysiology. Failure to regenerate upon trauma is thought to be one of the underlying causes for degenerative diseases, including OA. To investigate why lesions within an OA environment fail to heal, a heterogeneous cell population was isolated from the synovial fluid (SF) of OA patients. The cells' ability to undergo processes required for functional tissue regeneration was evaluated in the presence or absence of autologous SF. The obtained mechanistic findings were then used for the development of an immunomodulatory cell treatment, aimed to restore the pro-regenerative environment. Intra-articular injection in a clinical compassionate use study showed that the treatment restored the articular cartilage and joint homeostasis of OA patients. These findings confirm the role of pro-regenerative immune cells and their targeted influence on progenitor cells for degenerative joint disease therapies.

The Role of C-X-C Chemokines in Staphylococcus aureus Endophthalmitis

Purpose

To test the hypothesis that the C-X-C chemokines CXCL1, CXCL2, and CXCL10 contribute to inflammation during Staphylococcus aureus endophthalmitis.

Methods

S. aureus endophthalmitis was induced by intravitreal injection of 5000 colony forming units of S. aureus into the eyes of C57BL/6J, CXCL1-/-, CXCL2-/-, or CXCL10-/- mice. At 12, 24, and 36 hours postinfection, bacterial counts, intraocular inflammation, and retinal function were assessed. Based on these results, the effectiveness of intravitreal administration of anti-CXCL1 in reducing inflammation and improving retinal function was evaluated in S. aureus-infected C57BL/6J mice.

Results

We observed significant attenuation of inflammation and improvement in retinal function in CXCL1-/- mice relative to C57BL/6J at 12 hours but not at 24 or 36 hours postinfection with S. aureus. Co-administration of anti-CXCL1 antibodies with S. aureus, however, did not improve retinal function or reduce inflammation at 12 hours postinfection. In CXCL2-/- and CXCL10-/- mice, retinal function and intraocular inflammation were not significantly different from those of C57BL/6J mice at 12 and 24 hours postinfection. At 12, 24, or 36 hours, an absence of CXCL1, CXCL2, or CXCL10 did not alter intraocular S. aureus concentrations.

Conclusions

CXCL1 appears to contribute to the early host innate response to S. aureus endophthalmitis, but treatment with anti-CXCL1 did not effectively limit inflammation in this infection. CXCL2 and CXCL10 did not seem to play an integral role in inflammation during the early stages of S. aureus endophthalmitis.

The diversified hydrogels for biomedical applications and their imperative roles in tissue regeneration

Repair and regeneration of tissues after injury are complex pathophysiological processes. Microbial infection, malnutrition, and an ischemic and hypoxic microenvironment in the injured area can impede the typical healing cascade. Distinguished by biomimicry of the extracellular matrix, high aqueous content, and diverse functions, hydrogels have revolutionized clinical practices in tissue regeneration owing to their outstanding hydrophilicity, biocompatibility, and biodegradability. Various hydrogels such as smart hydrogels, nanocomposite hydrogels, and acellular matrix hydrogels are widely used for applications ranging from bench-scale to an industrial scale. In this review, some emerging hydrogels in the biomedical field are briefly discussed. The protective roles of hydrogels in wound dressings and their diverse biological effects on multiple tissues such as bone, cartilage, nerve, muscle, and adipose tissue are also discussed. The vehicle functions of hydrogels for chemicals and cell payloads are detailed. Additionally, this review emphasizes the particular characteristics of hydrogel products that promote tissue repair and reconstruction such as anti-infection, inflammation regulation, and angiogenesis.

Nitration of chemokine CXCL8 acts as a natural mechanism to limit acute inflammation

Chemokine CXCL8 is a key facilitator of the human host immune response, mediating neutrophil migration, and activation at the site of infection and injury. The oxidative burst is an important effector mechanism which leads to the generation of reactive nitrogen species (RNS), including peroxynitrite. The current study was performed to determine the potential for nitration to alter the biological properties of CXCL8 and its detection in human disease. Here, we show peroxynitrite nitrates CXCL8 and thereby regulates neutrophil migration and activation. The nitrated chemokine was unable to induce transendothelial neutrophil migration in vitro and failed to promote leukocyte recruitment in vivo. This reduced activity is due to impairment in both G protein-coupled receptor signaling and glycosaminoglycan binding. Using a novel antibody, nitrated CXCL8 was detected in bronchoalveolar lavage samples from patients with pneumonia. These findings were validated by mass spectrometry. Our results provide the first direct evidence of chemokine nitration in human pathophysiology and suggest a natural mechanism that limits acute inflammation.

Microalgae-Based Biohybrid Microrobot for Accelerated Diabetic Wound Healing

A variety of wound healing platforms have been proposed to alleviate the hypoxic condition and/or to modulate the immune responses for the treatment of chronic wounds in diabetes. However, these platforms with the passive diffusion of therapeutic agents through the blood clot result in the relatively low delivery efficiency into the deep wound site. Here, a microalgae-based biohybrid microrobot for accelerated diabetic wound healing is developed. The biohybrid microrobot autonomously moves at velocity of 33.3 µm s^-1 and generates oxygen for the alleviation of hypoxic condition. In addition, the microrobot efficiently bound with inflammatory chemokines of interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) for modulating the immune responses. The enhanced penetration of microrobot is corroborated by measuring fibrin clots in biomimetic wound using microfluidic devices and the enhanced retention of microrobot is confirmed in the real wounded mouse skin tissue. After deposition on the chronic wound in diabetic mice without wound dressing, the wounds treated with microrobots are completely healed after 9 days with the significant decrease of inflammatory cytokines below 31% of the control level and the upregulated angiogenesis above 20 times of CD31⁺ cells. These results confirm the feasibility of microrobots as a next-generation platform for diabetic wound healing.

Acute Inflammation in Tissue Healing

There are well-established links between acute inflammation and successful tissue repair across evolution. Innate immune reactions contribute significantly to pathogen clearance and activation of subsequent reparative events. A network of molecular and cellular regulators supports antimicrobial and tissue repair functions throughout the healing process. A delicate balance must be achieved between protection and the potential for collateral tissue damage associated with overt inflammation. In this review, we summarize the contributions of key cellular and molecular components to the acute inflammatory process and the effective and timely transition toward activation of tissue repair mechanisms. We further discuss how the disruption of inflammatory responses ultimately results in chronic non-healing injuries.

Hyperbaric oxygen therapy and chemokine administration - a combination with potential therapeutic value for treating diabetic wounds

Non-healing wounds impart serious medical problems to people with diabetes. Amongst 15% of diabetic patients, the incidence of foot ulcer is the most prevailing, which confers a significant risk of limb amputation, mainly due to hypoxia and impairment in cell signaling. Alteration in the expression of chemokines and the related factors in diabetic conditions delays the recruitment of different cell types, including fibroblasts, keratinocytes, and immune cells such as macrophages to the site of injury, further impairing neovasculogenesis, re-epithelialization, and extracellular matrix formation. Thus, proper activation of effector cells through an accurate signal pathway is necessary for better therapeutic application. Hyperbaric oxygen therapy (HBOT) is the current treatment prescribed by medical practitioners, shown to have increased the wound healing rate by reducing the need for significant amputation among the diabetic population. However, the risk of morbidity associated with HBOT needs complete attention through rigorous research to avoid adverse outcomes. Altering the level of pro-angiogenic chemokines may regulate the inflammatory response, further promote vascularization, and enhance the complete healing of wounds in diabetic patients. Thus, a combination of better therapeutic approaches could pave the way for developing a successful treatment for diabetic foot and wound healing.

Anti-inflammatory hydrogel dressings and skin wound healing

Hydrogels are promising and widely utilized in the biomedical field. In recent years, the anti-inflammatory function of hydrogel dressings has been significantly improved, addressing many clinical challenges presented in ongoing endeavours to promote wound healing. Wound healing is a cascaded and highly complex process, especially in chronic wounds, such as diabetic and severe burn wounds, in which adverse endogenous or exogenous factors can interfere with inflammatory regulation, leading to the disruption of the healing process. Although insufficient wound inflammation is uncommon, excessive inflammatory infiltration is an almost universal feature of chronic wounds, which impedes a histological repair of the wound in a predictable biological step and chronological order. Therefore, resolving excessive inflammation in wound healing is essential. In the past 5 years, extensive research has been conducted on hydrogel dressings to address excessive inflammation in wound healing, specifically by efficiently scavenging excessive free radicals, sequestering chemokines and promoting M1 -to-M2 polarization of macrophages, thereby regulating inflammation and promoting wound healing. In this study, we introduced novel anti-inflammatory hydrogel dressings and demonstrated innovative methods for their preparation and application to achieve enhanced healing. In addition, we summarize the most important properties required for wound healing and discuss our analysis of potential challenges yet to be addressed.

Nanozymes for Regenerative Medicine

Nanozymes refer to nanomaterials that catalyze enzyme substrates into products under relevant physiological conditions following enzyme kinetics. Compared to natural enzymes, nanozymes possess the characteristics of higher stability, easier preparation, and lower cost. Importantly, nanozymes possess the magnetic, fluorescent, and electrical properties of nanomaterials, making them promising replacements for natural enzymes in industrial, biological, and medical fields. On account of the rapid development of nanozymes recently, their application potentials in regeneration medicine are gradually being explored. To highlight the achievements in the regeneration medicine field, this review summarizes the catalytic mechanism of four types of representative nanozymes. Then, the strategies to improve the biocompatibility of nanozymes are discussed. Importantly, this review covers the recent advances in nanozymes in tissue regeneration medicine including wound healing, nerve defect repair, bone regeneration, and cardiovascular disease treatment. In addition, challenges and prospects of nanozyme researches in regeneration medicine are summarized.

Chemokines network in bone metastasis: Vital regulators of seeding and soiling

Chemokines are well equipped with chemo-attractive signals that can regulate cancer cell trafficking to specific organ sites. Currently, updated concepts have revealed the diverse role of chemokines in the biology of cancer initiation and progression. Genomic instabilities and alterations drive tumor heterogeneity, providing more options for the selection and metastatic progression to cancer cells. Tumor heterogeneity and acquired drug resistance are the main obstacles in managing cancer therapy and the primary root cause of metastasis. Studies emphasize that multiple chemokine/receptor axis are involved in cancer cell-mediated organ-specific distant metastasis. One of the persuasive mechanisms for heterogeneity and subsequent events is sturdily interlinked with the crosstalk between chemokines and their receptors on cancer cells and tissue-specific microenvironment. Among different metastatic niches, skeletal metastasis is frequently observed in the late stages of prostate, breast, and lung cancer and significantly reduces the survival of cancer patients. Therefore, it is crucial to elucidate the role of chemokines and their receptors in metastasis and bone remodeling. Here, we review the potential chemokine/receptor axis in tumorigenesis, tumor heterogeneity, metastasis, and vicious cycle in bone microenvironment.

Role of CXCR3 in fibrotic tissue responses

Development of fibrosis leads to end stage diseases that defy treatments across all organs. This ensues as chronic inflammation is not dampened by physiologic processes that issue in the resolution phase of wound healing. Thus, these conditions can be considered diseases of "failure to heal". In the absence of broadly viable treatments, it is proposed to examine key switches in wound healing resolution to seek insights into novel approaches. Signaling through the GPCR CXCR3 has been shown to be one such critical player in this physiologic transition that limits and even reverses early fibrosis. As such, a number of investigators and early stage technology companies have posited that triggering this signaling network would limit fibrosis. While there are some conflicting results, a consensus is emerging that pharmacologic interventions that promote signaling through this pathway represent innovative ways to limit fibrotic diseases.

The Role of Inflammatory Mediators in Colorectal Cancer Hepatic Metastasis

Colorectal cancer (CRC) is the second leading cause of death in cancer patients in the USA, whereas the major cause of CRC deaths is hepatic metastases. The liver is the most common site of metastasis in patients with CRC due to hepatic portal veins receiving blood from the digestive tract. Understanding the cellular and molecular mechanisms of hepatic metastases is of dire need for the development of potent targeted therapeutics. Immuno-signaling molecules including cytokines and chemokines play a pivotal role in hepatic metastases from CRC. This brief review discusses the involvement of three representative cytokines (TNF-α, IL-6 and IL-1β), a lipid molecule PGE2 and two chemokines (CXCL1 and CXCL2) in the process of CRC liver metastases.

Glycosaminoglycan-Based Hydrogel Delivery System Regulates the Wound Microenvironment to Rescue Chronic Wound Healing

Chronic wounds cannot proceed through the normal, orderly, and timely sequence of repair. The adverse cycle between excess reactive oxide species (ROS) and a persistent inflammatory response is an important mechanism of impaired wound healing. Herein, by combining the intrinsic bioactivities of natural polysaccharides and natural drugs, a glycosaminoglycan-based hydrogel delivery system is proposed to regulate the wound microenvironment. Dynamic supramolecular cross-linking enables the hydrogel to easily encapsulate the drug and fully fill the wound area. As the backbone of the hydrogel, heparin captures inflammatory chemokines at the wound site, while hyaluronic acid mimics the function of ECM. The hydrophobic drug curcumin has been ingeniously encapsulated in the hydrogel through micellization, thereby exerting good ROS scavenging ability and anti-inflammatory activity. Evaluations in diabetic mice showed that this antioxidant and anti-inflammatory hydrogel was effective in reducing the influx of immune cells at the wound site and in down-regulating the inflammatory response. Accelerated wound healing was also observed, as evidenced by faster re-epithelialization and better ECM remodeling. The proposed hydrogel can regulate the microenvironment of wounds from multiple aspects and thereby achieve regression of wound repair, which may provide a new therapeutic strategy for chronic wounds.

Gene expression analysis of intestinal IL-8, IL-17 A and IL-10 in patients with celiac and inflammatory bowel diseases

BACKGROUND

Celiac disease (CeD) and inflammatory bowel disease (IBD) are accompanied by impaired immune responses. To study the immune regulation of these diseases, we evaluated the expression levels of pro-inflammatory (IL-8 and IL-17 A) and anti-inflammatory (IL-10) cytokines in intestinal biopsy specimens of CeD and IBD patients in comparison to healthy subjects.

METHODS AND RESULTS

Intestinal biopsies were collected from 33 patients with IBD, 47 patients with CeD, and 20 healthy individuals. Total RNA was extracted and mRNA expression levels of IL-8, IL-17 A and IL-10 were assessed by qPCR. P-value < 0.05 was considered statistically significant. The expression levels of IL-8 and IL-17 A were higher in biopsies of IBD (UC and CD) and CeD patients compared to the control group (P < 0.05). IBD patients (UC and CD) had higher IL-8 intestinal level than CeD patients (P < 0.0001 and P = 0.0007, respectively). The expression of IL-10 was significantly down-regulated in intestinal biopsies of CeD and IBD patients compared with controls (P < 0.001). In addition, the expression level of this cytokine was significantly lower in IBD patients (P < 0.001 for UC patients and P < 0.0001 for CD patients) than CeD group.

CONCLUSIONS

The three selected pro- and anti-inflammatory cytokines showed a similar expression pattern in both IBD and CeD patients. As IBD and CeD are immune-mediated disorders and are accompanied by inflammatory events, the understanding of the similarities and differences among them can help researchers to find out useful candidate therapeutic protocols. We suggest that larger cohort studies be organized to achieve more insights into this regulation.

Role of chemokines in breast cancer

Chemokines belong to a family of chemoattractant cytokines and are well known to have an essential role in various cancer aetiologies. Multiplesubsets of immune cells are recruited and enrolled into the tumor microenvironment through interactions between chemokines and their specific receptors. These populations and their interactions have a distinct impact on tumor growth, progression, and treatment outcomes. While it is clear that many chemokines and their cognate receptors can be detected in breast and other cancers, the role of each chemokine and receptor has yet to be determined. This review focuses on the main chemokines that play a crucial role in the tumor microenvironment, emphasizing breast cancer. We have also discussed the techniques used to identify the chemokines and their future implication in the early diagnosis of cancer. In-depth knowledge of chemokines and their role in breast cancer progression can provide specific targets for breast cancer biotherapy.

Cellular and biological factors involved in healing wounds and burns and treatment options in tissue engineering

Severe traumatic wounds and burns have a high chance of mortality and can leave survivors with many functional disabilities and cosmetic problems, including scars. The healing process requires a harmonious interplay of various cells and growth factors. Different structures of the skin house numerous cells, matrix components and growth factors. Any disturbance in the balance between these components can impair the healing process. The function of cells and growth factors can be manipulated and facilitated to aid tissue repair. In the current review, the authors focus on the importance of the skin microenvironment, the pathophysiology of various types of burns, mechanisms and factors involved in skin repair and wound healing and regeneration of the skin using tissue engineering approaches.

Bioactive Materials Promote Wound Healing through Modulation of Cell Behaviors

Skin wound repair is a multistage process involving multiple cellular and molecular interactions, which modulate the cell behaviors and dynamic remodeling of extracellular matrices to maximize regeneration and repair. Consequently, abnormalities in cell functions or pathways inevitably give rise to side effects, such as dysregulated inflammation, hyperplasia of nonmigratory epithelial cells, and lack of response to growth factors, which impedes angiogenesis and fibrosis. These issues may cause delayed wound healing or even non-healing states. Current clinical therapeutic approaches are predominantly dedicated to preventing infections and alleviating topical symptoms rather than addressing the modulation of wound microenvironments to achieve targeted outcomes. Bioactive materials, relying on their chemical, physical, and biological properties or as carriers of bioactive substances, can affect wound microenvironments and promote wound healing at the molecular level. By addressing the mechanisms of wound healing from the perspective of cell behaviors, this review discusses how bioactive materials modulate the microenvironments and cell behaviors within the wounds during the stages of hemostasis, anti-inflammation, tissue regeneration and deposition, and matrix remodeling. A deeper understanding of cell behaviors during wound healing is bound to promote the development of more targeted and efficient bioactive materials for clinical applications.

Mesenchymal Stem Cell-Derived Exosomes Loaded with miR-155 Inhibitor Ameliorate Diabetic Wound Healing

Diabetic wounds are one of the debilitating complications that affect up to 20% of diabetic patients. Despite the advent of extensive therapies, the recovery rate is unsatisfactory, and approximately, 25% of patients undergo amputation, thereby demanding alternative therapeutic strategies. On the basis of the individual therapeutic roles of the miR-155 inhibitor and mesenchymal stem cells (MSC)-derived exosomes, we conjectured that the combination of the miR-155 inhibitor and MSC-derived exosomes would have synergy in diabetic wound healing. Herein, miR-155-inhibitor-loaded MSC-derived exosomes showed synergistic effects in keratinocyte migration, restoration of FGF-7 levels, and anti-inflammatory action, leading to accelerated wound healing mediated by negative regulation of miR-155, using an in vitro co-culture model and in vivo mouse model of the diabetic wound. Furthermore, treatment with miR-155-inhibitor-loaded MSC-derived exosomes led to enhanced collagen deposition, angiogenesis, and re-epithelialization in diabetic wounds. This study revealed the therapeutic potential of miR-155-inhibitor-loaded MSC-derived exosomes in diabetic wound healing and opened the doors for encapsulating miRNAs along with antibiotics within the MSC-derived exosomes toward improved management of chronic, nonhealing diabetic wounds.

Thy-1 (CD90), Integrins and Syndecan 4 are Key Regulators of Skin Wound Healing

Acute skin wound healing is a multistage process consisting of a plethora of tightly regulated signaling events in specialized cells. The Thy-1 (CD90) glycoprotein interacts with integrins and the heparan sulfate proteoglycan syndecan 4, generating a trimolecular complex that triggers bi-directional signaling to regulate diverse aspects of the wound healing process. These proteins can act either as ligands or receptors, and they are critical for the successful progression of wound healing. The expression of Thy-1, integrins, and syndecan 4 is controlled during the healing process, and the lack of expression of any of these proteins results in delayed wound healing. Here, we review and discuss the roles and regulatory events along the stages of wound healing that support the relevance of Thy-1, integrins, and syndecan 4 as crucial regulators of skin wound healing.

Possible Role of Circulating Bone Marrow Mesenchymal Progenitors in Modulating Inflammation and Promoting Wound Repair

Circulating bone marrow mesenchymal progenitors (BMMPs) are known to be potent antigen-presenting cells that migrate to damaged tissue to secrete cytokines and growth factors. An altered or dysregulated inflammatory cascade leads to a poor healing outcome. A skin model developed in our previous study was used to observe the immuno-modulatory properties of circulating BMMP cells in inflammatory chronic wounds in a scenario of low skin perfusion. BMMPs were analysed exclusively and in conjunction with recombinant tumour necrosis factor alpha (TNFα) and recombinant hepatocyte growth factor (HGF) supplementation. We analysed the expression levels of interleukin-8 (IL-8) and ecto-5'-nucleotidase (CD73), together with protein levels for IL-8, stem cell factor (SCF), and fibroblast growth factor 1 (FGF-1). The successfully isolated BMMPs were positive for both hemopoietic and mesenchymal markers and showed the ability to differentiate into adipocytes, chondrocytes, and osteocytes. Significant differences were found in IL-8 and CD73 expressions and IL-8 and SCF concentrations, for all conditions studied over the three time points taken into consideration. Our data suggests that BMMPs may modulate the inflammatory response by regulating IL-8 and CD73 and influencing IL-8 and SCF protein secretions. In conclusion, we suggest that BMMPs play a role in wound repair and that their induced application might be suitable for scenarios with a low skin perfusion.

Liver is a primary source of insulin-like growth factor-1 in skin wound healing

Insulin-like growth factor (IGF)-1 plays important role in tissue repair through its ability to stimulate wound cell activity. While IGF-1 is expressed locally by wound cells, liver-derived IGF-1 is also present at high levels in the circulation, and the contributions of local vs circulating IGF-1 to wound levels remain undefined. The hypothesis of this study was that liver is a primary source of IGF-1 during skin wound healing. To test this hypothesis, we utilized a model that allows inducible ablation of IGF-1 specifically in liver of adult mice. We demonstrate that ablation of liver IGF-1 leads to >85% loss of circulating IGF-1 and ~60% decrease in wound IGF-1 during the proliferative phase of healing in both male and female mice. This reduction of liver-derived IGF-1 did not alter local mRNA expression of Igf1 in wounds. Knockdown of liver IGF-1 significantly delayed wound re-epithelialization and reduced granulation tissue formation and collagen deposition. Knockdown of liver IGF-1 also significantly reduced angiogenesis and resulted in persistent macrophage accumulation. In summary, liver is a primary source of IGF-1 in skin wounds and contributes to many aspects of both epithelial and dermal healing.

C-X-C Chemokines Influence Intraocular Inflammation During Bacillus Endophthalmitis

Purpose

The purpose of this study was to explore the C-X-C chemokines CXCL2 and CXCL10 as potential anti-inflammatory targets for Bacillus endophthalmitis.

Methods

Bacillus endophthalmitis was induced in C57BL/6J, CXCL2^−/−, and CXCL10^−/− mice. At specific times postinfection, eyes were analyzed for Bacillus, retinal function, and inflammation. The efficacies of intravitreal anti-CXCL2 and anti-CXCL10 with or without gatifloxacin in B. cereus endophthalmitis were also assessed using the same techniques.

Results

Despite similar Bacillus growth in eyes of C57BL/6J, CXCL2^−/−, and CXCL10^−/− mice, retinal function retention was greater in eyes of CXCL2^−/− and CXCL10^−/− mice compared to that of C57BL/6J mice. Neutrophil migration into eyes of CXCL2^−/− and CXCL10^−/− mice was reduced to a greater degree compared to that of eyes of C57BL/6J mice. Infected CXCL2^−/− and CXCL10^−/− mouse eyes had significantly less inflammation compared to that of C57BL/6J eyes. Retinal structures in infected eyes of CXCL2^−/− mice were preserved for a longer time than in CXCL10^−/− eyes. Compared to untreated eyes, there was less inflammation and significant retention of retinal function in eyes treated with anti-CXCL2 and anti-CXCL10 with or without gatifloxacin.

Conclusions

For Bacillus endophthalmitis, the absence of CXCL2 or CXCL10 in mice resulted in retained retinal function and less inflammation. The absence of CXCL2 led to a better clinical outcome than the absence of CXCL10. The use of anti-CXCL2 and anti-CXCL10 limited inflammation during B. cereus endophthalmitis. These results highlight the utility of CXCL2 and CXCL10 as potential targets for anti-inflammatory therapy that can be tested in conjunction with antibiotics for improving treating Bacillus endophthalmitis.

Macrophage-mediated inflammation in diabetic wound repair

Non-healing wounds in Type 2 Diabetes (T2D) patients represent the most common cause of amputation in the US, with an associated 5-year mortality of nearly 50%. Our lab has examined tissue from both T2D murine models and human wounds in order to explore mechanisms contributing to impaired wound healing. Current published data in the field point to macrophage function serving a pivotal role in orchestrating appropriate wound healing. Wound macrophages in mice and patients with T2D are characterized by a persistent inflammatory state; however, the mechanisms that control this persistent inflammatory state are unknown. Current literature demonstrates that gene regulation through histone modifications, DNA modifications, and microRNA can influence macrophage plasticity during wound healing. Further, accumulating studies reveal the importance of cells such as adipocytes, infiltrating immune cells (PMNs and T cells), and keratinocytes secrete factors that may help drive macrophage polarization. This review will examine the role of macrophages in the wound healing process, along with their function and interactions with other cells, and how it is perturbed in T2D. We also explore epigenetic factors that regulate macrophage polarization in wounds, while highlighting the emerging role of other cell types that may influence macrophage phenotype following tissue injury.

Construction of heparin-based hydrogel incorporated with Cu5.4O ultrasmall nanozymes for wound healing and inflammation inhibition

Excessive production of inflammatory chemokines and reactive oxygen species (ROS) can cause a feedback cycle of inflammation response that has a negative effect on cutaneous wound healing. The use of wound-dressing materials that simultaneously absorb chemokines and scavenge ROS constitutes a novel 'weeding and uprooting' treatment strategy for inflammatory conditions. In the present study, a composite hydrogel comprising an amine-functionalized star-shaped polyethylene glycol (starPEG) and heparin for chemokine sequestration as well as Cu5.4O ultrasmall nanozymes for ROS scavenging (Cu5.4O@Hep-PEG) was developed. The material effectively adsorbs the inflammatory chemokines monocyte chemoattractant protein-1 and interleukin-8, decreasing the migratory activity of macrophages and neutrophils. Furthermore, it scavenges the ROS in wound fluids to mitigate oxidative stress, and the sustained release of Cu5.4O promotes angiogenesis. In acute wounds and impaired-healing wounds (diabetic wounds), Cu5.4O@Hep-PEG hydrogels outperform the standard-of-care product Promogram® in terms of inflammation reduction, increased epidermis regeneration, vascularization, and wound closure.

Chemokine-Capturing Wound Contact Layer Rescues Dermal Healing

Excessive inflammation often impedes the healing of chronic wounds. Scavenging of chemokines by multiarmed poly(ethylene glycol)-glycosaminoglycan (starPEG-GAG) hydrogels has recently been shown to support regeneration in a diabetic mouse chronic skin wound model. Herein, a textile-starPEG-GAG composite wound contact layer (WCL) capable of selectively sequestering pro-inflammatory chemokines is reported. Systematic variation of the local and integral charge densities of the starPEG-GAG hydrogel component allows for tailoring its affinity profile for biomolecular signals of the wound milieu. The composite WCL is subsequently tested in a large animal (porcine) model of human wound healing disorders. Dampening excessive inflammatory signals without affecting the levels of pro-regenerative growth factors, the starPEG-GAG hydrogel-based WCL treatment induced healing with increased granulation tissue formation, angiogenesis, and deposition of connective tissue (collagen fibers). Thus, this biomaterials technology expands the scope of a new anti-inflammatory therapy toward clinical use.

Extracellular Vesicles (Secretomes) from Human Trophoblasts Promote the Regeneration of Skin Fibroblasts

To date, placental trophoblasts have been of interest in the fields of obstetrics and gynecology, mainly due to their involvement in the formation of a connection between the mother and fetus that aids in placental development and fetal survival. However, the regenerative capacities of trophoblasts for application in regenerative medicine and tissue engineering are poorly understood. Here, we aim to determine the skin regeneration and anti-aging capacities of trophoblast-derived conditioned medium (TB-CM) and exosomes (TB-Exos) using human normal dermal fibroblasts (HNDFs). TB-CM and TB-Exos treatments significantly elevated the migration and proliferation potencies of HNDF cells in a dose- and time-dependent manner. When RNA sequencing (RNA-seq) was used to investigate the mechanism underlying TB-CM-induced cell migration on scratch-wounded HNDFs, the increased expression of genes associated with C-X-C motif ligand (CXCL) chemokines, toll-like receptors, and nuclear factor-kappa B (NF-κB) signaling was observed. Furthermore, treatment of intrinsically/extrinsically senescent HNDFs with TB-CM resulted in an enhanced rejuvenation of HNDFs via both protection and restoration processes. Gene expression of extracellular matrix components in the skin dermis significantly increased in TB-CM- and TB-Exos-treated HNDFs. These components are involved in the TB-CM and Exo-mediated regeneration and anti-aging of HNDFs. Thus, this study demonstrated the regenerative and anti-aging efficacies of trophoblast-derived secretomes, suggesting their potential for use in interventions for skin protection and treatment.

Capturing dynamic biological signals via bio-mimicking hydrogel for precise remodeling of soft tissue

Soft tissue remodeling is a sophisticated process that sequentially provides dynamic biological signals to guide cell behavior. However, capturing these signals within hydrogel and directing over time has still been unrealized owing to the poor comprehension of physiological processes. Here, a bio-mimicking hydrogel is designed via thiol-ene click reaction to capture the early physical signal triggered by inflammation, and the chemical signals provided with chemokine and natural adhesion sites, which guaranteed the precise soft tissue remodeling. This bio-mimicking hydrogel efficiently facilitated cell anchoring, migration, and invasion in the 3D matrix due to the permissive space and the interaction with integrin receptors. Besides, the covalently grafted chemokine-like peptide is optimal for colonization and functional differentiation of endothelial cells through a HIF-1α dependent signal pathway. Furthermore, the early polarization of macrophages, collagen deposition and angiogenesis in rat acute wound model, and the increased blood perfusion in mouse skin flap model have confirmed that the bio-mimicking hydrogel realized precise soft tissue remodeling and opens new avenues for the phased repair of different tissues such as nerve, myocardium, and even bone.

Microglia in Aging and Alzheimer's Disease: A Comparative Species Review

Microglia are the primary immune cells of the central nervous system that help nourish and support neurons, clear debris, and respond to foreign stimuli. Greatly impacted by their environment, microglia go through rapid changes in cell shape, gene expression, and functional behavior during states of infection, trauma, and neurodegeneration. Aging also has a profound effect on microglia, leading to chronic inflammation and an increase in the brain's susceptibility to neurodegenerative processes that occur in Alzheimer's disease. Despite the scientific community's growing knowledge in the field of neuroinflammation, the overall success rate of drug treatment for age-related and neurodegenerative diseases remains incredibly low. Potential reasons for the lack of translation from animal models to the clinic include the use of a single species model, an assumption of similarity in humans, and ignoring contradictory data or information from other species. To aid in the selection of validated and predictive animal models and to bridge the translational gap, this review evaluates similarities and differences among species in microglial activation and density, morphology and phenotype, cytokine expression, phagocytosis, and production of oxidative species in aging and Alzheimer's disease.

Biofilm-Innate Immune Interface: Contribution to Chronic Wound Formation

Delayed wound healing can cause significant issues for immobile and ageing individuals as well as those living with co-morbid conditions such as diabetes, cardiovascular disease, and cancer. These delays increase a patient’s risk for infection and, in severe cases, can result in the formation of chronic, non-healing ulcers (e.g., diabetic foot ulcers, surgical site infections, pressure ulcers and venous leg ulcers). Chronic wounds are very difficult and expensive to treat and there is an urgent need to develop more effective therapeutics that restore healing processes. Sustained innate immune activation and inflammation are common features observed across most chronic wound types. However, the factors driving this activation remain incompletely understood. Emerging evidence suggests that the composition and structure of the wound microbiome may play a central role in driving this dysregulated activation but the cellular and molecular mechanisms underlying these processes require further investigation. In this review, we will discuss the current literature on: 1) how bacterial populations and biofilms contribute to chronic wound formation, 2) the role of bacteria and biofilms in driving dysfunctional innate immune responses in chronic wounds, and 3) therapeutics currently available (or underdevelopment) that target bacteria-innate immune interactions to improve healing. We will also discuss potential issues in studying the complexity of immune-biofilm interactions in chronic wounds and explore future areas of investigation for the field.

CXC Chemokines as Therapeutic Targets and Prognostic Biomarkers in Skin Cutaneous Melanoma Microenvironment

Background

Skin Cutaneous Melanoma (SKCM) is a tumor of the epidermal melanocytes induced by gene activation or mutation. It is the result of the interaction between genetic, constitutional, and environmental factors. SKCM is highly aggressive and is the most threatening skin tumor. The incidence of the disease is increasing year by year, and it is the main cause of death in skin tumors around the world. CXC chemokines in the tumor microenvironment can regulate the transport of immune cells and the activity of tumor cells, thus playing an anti-tumor immunological role and affecting the prognosis of patients. However, the expression level of CXC chemokine in SKCM and its effect on prognosis are still unclear.

Method

Oncomine, UALCAN, GEPIA, STRING, GeneMANIA, cBioPortal, TIMER, TRRUST, DAVID 6.8, and Metascape were applied in our research.

Result

The transcription of CXCL1, CXCL5, CXCL8, CXCL9, CXCL10, and CXCL13 in SKCM tissues were significantly higher than those in normal tissues. The pathological stage of SKCM patients is closely related to the expression of CXCL4, CXCL9, CXCL10, CXCL11, CXCL12, and CXCL13. The prognosis of SKCM patients with low transcription levels of CXCL4, CXCL9, CXCL10, CXCL11, and CXCL13 is better. The differential expression of CXC chemokines is mainly associated with inflammatory response, immune response, and cytokine mediated signaling pathways. Our data indicate that the key transcription factors of CXC chemokines are RELA, NF-κB1 and SP1. The targets of CXC chemokines are mainly LCK, LYN, SYK, MAPK2, MAPK12, and ART. The relationship between CXC chemokine expression and immune cell infiltration in SKCM was closed.

Conclusions

Our research provides a basis for screening SKCM biomarkers, predicting prognosis, and choosing immunotherapy.

Non-18F-FDG/18F-NaF Radiotracers Proposed for the Diagnosis and Management of Diseases of the Heart and Vasculature

¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) and ¹⁸F-sodium fluoride (¹⁸F-NaF) are front-runners in PET. However, these tracers have limitations in the imaging of diseases in the heart. A multitude of other radiotracers have been identified as potentially useful PET agents in the identification of cardiovascular disease. This critical review examines recent studies with the use of non-¹⁸F-FDG/¹⁸F-NaF radiotracers in the identification and surveillance of cardiovascular diseases. We highlight the need for further investigation into alternative PET radiotracers to demonstrate their clinical value in the management of these pathologies.

Levels of Cyclooxygenase 2, Interleukin-6, and Tumour Necrosis Factor-α in Fibroblast Cell Culture Models after Photobiomodulation at 660 nm

Chemicals and signaling molecules released by injured cells at the beginning of wound healing prompt inflammation. In diabetes, prolonged inflammation is one of the probable causes for delayed wound healing. Increased levels of cyclooxygenase-2 (cox-2), interleukin–6 (IL-6), and tumour necrosis factor-alpha (TNF-α) are associated with the inflammatory response and in diabetes, and increased levels of these contribute to chronic wounds that do not heal. Rising levels of cox-2, IL-6, and TNF-α have also been associated with increased oxidative stress. Photobiomodulation (PBM) may impact wound healing processes by affecting the signaling pathways and molecules pertinent to tissue repair. In the present study, the effect of PBM (wavelength: 660 nm; energy density: 5 J/cm²) on levels of cox-2, IL-6, and TNF-α was determined in fibroblast cell culture models. Four WS1 models (normal, normal wounded, diabetic, and diabetic wounded) were irradiated at 660 nm, and the culture media was collected at 0, 24, and 48 h postirradiation. Cells that were not irradiated (0 J/cm²) served as the controls. The following parameters were determined postirradiation: cell morphology using light microscopy, cell viability using the Trypan Blue exclusion assay, and levels of the inflammatory markers cox-2, IL-6, and TNF-α were measured using ELISA. Cell migration increased in the wounded groups over the 48 h interval after PBM; viability improved postirradiation in the diabetic wounded groups at 0 and 24 h (P ≤ 0.05 and P ≤ 0.01, respectively); levels of cox-2 decreased in normal and diabetic wounded groups at 0 h (P ≤ 0.001) and increased in the diabetic and diabetic wounded groups at 48 h postirradiation (P ≤ 0.05 and P ≤ 0.01, respectively), while levels of IL-6 decreased in the normal (P ≤ 0.01), diabetic (P ≤ 0.05), and diabetic wounded (P ≤ 0.001) groups at 24 h and in the diabetic and diabetic wounded groups at 48 h (P ≤ 0.05) postirradiation. TNF-α was decreased in the normal wounded groups (P ≤ 0.05) at 48 h. Through its effect on decreased IL-6 levels in diabetic cell models, PBM at 660 nm may be successful at decreasing oxidative stress; however, the present study also found an increase in cox-2 levels at 48 h postirradiation.

Molecular Changes Underlying Hypertrophic Scarring Following Burns Involve Specific Deregulations at All Wound Healing Stages (Inflammation, Proliferation and Maturation)

Excessive connective tissue accumulation, a hallmark of hypertrophic scaring, results in progressive deterioration of the structure and function of organs. It can also be seen during tumor growth and other fibroproliferative disorders. These processes result from a wide spectrum of cross-talks between mesenchymal, epithelial and inflammatory/immune cells that have not yet been fully understood. In the present review, we aimed to describe the molecular features of fibroblasts and their interactions with immune and epithelial cells and extracellular matrix. We also compared different types of fibroblasts and their roles in skin repair and regeneration following burn injury. In summary, here we briefly review molecular changes underlying hypertrophic scarring following burns throughout all basic wound healing stages, i.e. during inflammation, proliferation and maturation.

Cytokine-chemokine network driven metastasis in esophageal cancer; promising avenue for targeted therapy

Esophageal cancer (EC) is a disease often marked by aggressive growth and poor prognosis. Lack of targeted therapies, resistance to chemoradiation therapy, and distant metastases among patients with advanced disease account for the high mortality rate. The tumor microenvironment (TME) contains several cell types, including fibroblasts, immune cells, adipocytes, stromal proteins, and growth factors, which play a significant role in supporting the growth and aggressive behavior of cancer cells. The complex and dynamic interactions of the secreted cytokines, chemokines, growth factors, and their receptors mediate chronic inflammation and immunosuppressive TME favoring tumor progression, metastasis, and decreased response to therapy. The molecular changes in the TME are used as biological markers for diagnosis, prognosis, and response to treatment in patients. This review highlighted the novel insights into the understanding and functional impact of deregulated cytokines and chemokines in imparting aggressive EC, stressing the nature and therapeutic consequences of the cytokine-chemokine network. We also discuss cytokine-chemokine oncogenic potential by contributing to the Epithelial-Mesenchymal Transition (EMT), angiogenesis, immunosuppression, metastatic niche, and therapeutic resistance development. In addition, it discusses the wide range of changes and intracellular signaling pathways that occur in the TME. Overall, this is a relatively unexplored field that could provide crucial insights into tumor immunology and encourage the effective application of modulatory cytokine-chemokine therapy to EC.

Recombinant Myxoma Virus-Derived Immune Modulator M-T7 Accelerates Cutaneous Wound Healing and Improves Tissue Remodeling

Complex dermal wounds represent major medical and financial burdens, especially in the context of comorbidities such as diabetes, infection and advanced age. New approaches to accelerate and improve, or "fine tune" the healing process, so as to improve the quality of cutaneous wound healing and management, are the focus of intense investigation. Here, we investigate the topical application of a recombinant immune modulating protein which inhibits the interactions of chemokines with glycosaminoglycans, reducing damaging or excess inflammation responses in a splinted full-thickness excisional wound model in mice. M-T7 is a 37 kDa-secreted, virus-derived glycoprotein that has demonstrated therapeutic efficacy in numerous animal models of inflammatory immunopathology. Topical treatment with recombinant M-T7 significantly accelerated wound healing when compared to saline treatment alone. Healed wounds exhibited properties of improved tissue remodeling, as determined by collagen maturation. M-T7 treatment accelerated the rate of peri-wound angiogenesis in the healing wounds with increased levels of TNF, VEGF and CD31. The immune cell response after M-T7 treatment was associated with a retention of CCL2 levels, and increased abundances of arginase-1-expressing M2 macrophages and CD4 T cells. Thus, topical treatment with recombinant M-T7 promotes a pro-resolution environment in healing wounds, and has potential as a novel treatment approach for cutaneous tissue repair.