Combination of adrenomedullin with its binding protein accelerates cutaneous wound healing

A multifunctional chitosan-based hydrogel with self-healing, antibacterial, and immunomodulatory effects as wound dressing

Bacterial infection often leads to inflammatory responses and delays wound healing. Chitosan (CS)-based composite hydrogels can hold desirable mechanical properties and maintain excellent antibacterial abilities, and thus may be promising as wound dressings. Although CS-based hydrogels have been widely studied on the antibacterial and wound-healing abilities, their immunomodulatory abilities were rarely evaluated. Herein, we developed a multifunctional CS/Poly[2-(methacryloyloxy)ethyl] trimethyl ammonium chloride (PMETAC) hydrogel. In vitro, this hydrogel exhibited self-healing ability and excellent biocompatibility, promoted macrophage polarization towards M2 phenotype, and showed desirable antibacterial activity. In vivo, this hydrogel accelerated the wound regeneration process by reducing bacterial burden, increasing collagen deposition, stimulating angiogenesis, promoting macrophage polarization to M2 direction, and shifting the balance of T helper type 17 (Th17) cells towards anti-inflammatory regulatory T (Treg) cells. This work revealed the potential immunomodulatory effect of CS-based wound dressings and thus may provide a novel target for developing efficient wound healing tools.

Modern aspects of burn injury immunopathogenesis and immuno-biochemical markers of wound healing (review of literature)

Burns are one of the most common traumatic injuries in the world, representing a global public health problem. Major burns (severe burn injury or burn disease) are one of the most life-threatening injuries. There is a great need to identify and monitor the development of complications (sepsis and septic shock, coagulopathy and DIC) in burned patients. The basis of the pathogenesis of burn injury, as well as any general pathological process, is an inflammatory reaction, ultimately aimed at restoring the structure and function of the damaged tissue. A feature of the inflammatory reaction in burn injury is the scale of alteration of the skin and mucous membranes. The review presents the main aspects of the burn injuries immunopathogenesis and the features of post-burn immune dysfunction, manifested by disorders in the innate and adaptive immunity systems. Attention is focused on the role in the immunopathogenesis of developing systemic and local disorders in burn injury. Also the role are discussed of a minor subpopulations of lymphocytes (Treg-, Th-17-, γδT-cells) in the immunopathogenesis and in the bacterial infection protection. The characteristics of the main immuno-biochemical markers of burn injury (cytokines and growth factors, nitric oxide, matrix metalloproteases, bacteria concentration levels) are present. The prognostic role of these biomarkers in assessing of the severity degree of patients with burn injury and wound healing processes is shown. The review has been compiled using references from major databases such as RSCI, Web of Science, PubMed, Scopus and Google Scholar (up to march 2022). After obtaining all reports from database, the papers were carefully analyzed in order to find data related to the topic of this review (60 references).

Mesenchymal stromal cells in wound healing applications: role of the secretome, targeted delivery and impact on recessive dystrophic epidermolysis bullosa treatment

Mesenchymal stromal cells (MSCs) are multi-potent stromal-derived cells capable of self-renewal that possess several advantageous properties for wound healing, making them of interest to the field of dermatology. Research has focused on characterizing the unique properties of MSCs, which broadly revolve around their regenerative and more recently discovered immunomodulatory capacities. Because of ease of harvesting and expansion, differentiation potential and low immunogenicity, MSCs have been leading candidates for tissue engineering and regenerative medicine applications for wound healing, yet results from clinical studies have been variable, and promising pre-clinical work has been difficult to reproduce. Therefore, the specific mechanisms of how MSCs influence the local microenvironment in distinct wound etiologies warrant further research. Of specific interest in MSC-mediated healing is harnessing the secretome, which is composed of components known to positively influence wound healing. Molecules released by the MSC secretome can promote re-epithelialization and angiogenesis while inhibiting fibrosis and microbial invasion. This review focuses on the therapeutic interest in MSCs with regard to wound healing applications, including burns and diabetic ulcers, with specific attention to the genetic skin disease recessive dystrophic epidermolysis bullosa. This review also compares various delivery methods to support skin regeneration in the hopes of combating the poor engraftment of MSCs after delivery, which is one of the major pitfalls in clinical studies utilizing MSCs.

Mechanical forces induce an asthma gene signature in healthy airway epithelial cells

Bronchospasm compresses the bronchial epithelium, and this compressive stress has been implicated in asthma pathogenesis. However, the molecular mechanisms by which this compressive stress alters pathways relevant to disease are not well understood. Using air-liquid interface cultures of primary human bronchial epithelial cells derived from non-asthmatic donors and asthmatic donors, we applied a compressive stress and then used a network approach to map resulting changes in the molecular interactome. In cells from non-asthmatic donors, compression by itself was sufficient to induce inflammatory, late repair, and fibrotic pathways. Remarkably, this molecular profile of non-asthmatic cells after compression recapitulated the profile of asthmatic cells before compression. Together, these results show that even in the absence of any inflammatory stimulus, mechanical compression alone is sufficient to induce an asthma-like molecular signature.

Autonomic nerve dysfunction and impaired diabetic wound healing: The role of neuropeptides

Lower extremity ulcerations represent a major complication in diabetes mellitus and involve multiple physiological factors that lead to impairment of wound healing. Neuropeptides are neuromodulators implicated in various processes including diabetic wound healing. Diabetes causes autonomic and small sensory nerve fibers neuropathy as well as inflammatory dysregulation, which manifest with decreased neuropeptide expression and a disproportion in pro- and anti- inflammatory cytokine response. Therefore to fully understand the contribution of autonomic nerve dysfunction in diabetic wound healing it is crucial to explore the implication of neuropeptides. Here, we will discuss recent studies elucidating the role of specific neuropeptides in wound healing.

HIF1α/miR-199a/ADM feedback loop modulates the proliferation of human dermal microvascular endothelial cells (HDMECs) under hypoxic condition

Hypoxia-inducible factor 1α (HIF1α) plays a protective role in the hypoxia-induced cellular injury. In the present study, we attempted to investigate the role and mechanism of HIF1αin human dermal microvascular endothelial cells (hDMECs), a common-used cell model for researches on the hypoxia-induced injury during skin wounds healing. As revealed by ChIP and online tools prediction and confirmed by luciferase reporter and ChIP assays, HIF1A can bind to the promoter regions of ADM and miR-199a, while miR-199a directly binds to the 3'UTR of HIF1A and ADM. Hypoxia stress induces HIF1α and ADM expression while inhibits miR-199a expression. Under hypoxic condition, HIF1α knockdown increases the nucleus translocation of p65 and the release of TNF-α and IL-8, inhibits the proliferation and migration, while promotes the cellular permeability in HDMECs upon hypoxic stress, while ADM overexpression and miR-199a inhibition exerted an opposite effect on HDMECs. ADM overexpression or miR-199a inhibition could partially reverse the effect of HIF1A knockdown under hypoxia. In summary, we demonstrate a feedback loop consists of HIF1α, miR-199a, and ADM which protect HDMECs from hypoxia-induced cellular injury by modulating the inflammation response, cell proliferation, migration and permeability in HDMECs.

Combination Therapy Comprising a Static Magnetic Field with Contractility Improves Skin Wounds

Cutaneous wounds can present significant clinical problems because of abnormal healing after deep dermal damage. Despite technical advances in wound care, there are still unmet needs that result from inefficient treatment. In this study, we aimed to improve skin wound healing using a contractibility band with static magnetic field (SMF), termed a magnetic band (Mb). To examine the effect of the Mb on wound healing, full-thickness 15 × 35 mm excision wounds were surgically created on the dorsum of rats. An elastic and contractile band (nontreatment), or one neodymium magnet (Nd-1) or two magnets with an elastic and contractile band (Nd-2) were topically applied to the wound daily and the wound size was measured from day 1 to 7 after surgery. Nd-2 showed a significant (95%) reduction in the wound size on day 3. Histological analysis showed that proinflammatory cytokine levels were diminished by Nd-2, and granulation tissue and microvessels were increased compared with those in the sham group. During Mb-induced wound healing, apoptosis was significantly reduced and matrix remodeling-related factors were initially regulated. The results suggest that combination therapy comprising an SMF and an elastic and contractile band could be a promising tool to heal cutaneous wounds rapidly.

Promoting Wound Healing Using Low Molecular Weight Fucoidan in a Full-Thickness Dermal Excision Rat Model

Low molecular weight fucoidan (LMF) has been reported to possess anti-inflammatory and antioxidant activities. Thus, we examined the effects of LMF extracted from Undaria pinnatifida on dermal wounds. Five round dermal wounds were created on the dorsal back of rats, and they were then treated topically with distilled water (DW), Madecasol Care™ (MC) or LMF at 200, 100 and 50 mg/mL, twice a day for a week. There were dose-dependent increases in wound contraction in the groups receiving LMF but not in the MC group, compared with the DW. Histopathological examination revealed that LMF treatment accelerated wound healing, which was supported by increases in granular tissue formation on day four post-treatment but a decrease on day seven, accompanied by an evident reduction in inflammatory cells. In the LMF-treated wounds, collagen distribution and angiogenesis were increased in the granular tissue on days four and seven post-treatment. Immunoreactive cells for transforming growth factor-β1, vascular endothelial growth factor receptor-2 or matrix metalloproteinases 9 were also increased, probably due to tissue remodeling. Furthermore, LMF treatment reduced lipid peroxidation and increased antioxidant activities. These suggested that LMF promotes dermal wound healing via complex and coordinated antioxidant, anti-inflammatory and growth factor-dependent activities.

Exosomes Derived from Human Endothelial Progenitor Cells Accelerate Cutaneous Wound Healing by Promoting Angiogenesis Through Erk1/2 Signaling

Chronic skin wounds represent one of the most common and disabling complications of diabetes. Endothelial progenitor cells (EPCs) are precursors of endothelial cells and can enhance diabetic wound repair by facilitating neovascularization. Recent studies indicate that the transplanted cells exert therapeutic effects primarily via a paracrine mechanism and exosomes are an important paracrine factor that can be directly used as therapeutic agents for regenerative medicine. However, application of exosomes in diabetic wound repair has been rarely reported. In this study, we demonstrated that the exosomes derived from human umbilical cord blood-derived EPCs (EPC-Exos) possessed robust pro-angiogenic and wound healing effects in streptozotocin-induced diabetic rats. By using a series of in vitro functional assays, we found that EPC-Exos could be incorporated into endothelial cells and significantly enhance endothelial cells' proliferation, migration, and angiogenic tubule formation. Moreover, microarray analyses indicated that exosomes treatment markedly altered the expression of a class of genes involved in Erk1/2 signaling pathway. It was further confirmed with functional study that this signaling process was the critical mediator during the exosomes-induced angiogenic responses of endothelial cells. Therefore, EPC-Exos are able to stimulate angiogenic activities of endothelial cells by activating Erk1/2 signaling, which finally facilitates cutaneous wound repair and regeneration.

Complement factor H in its alternative identity as adrenomedullin-binding protein 1

Complement factor H has been extensively studied since its discovery 50 years ago, and its role in the complement system is quite well established. It has another role, however, as a binding protein for the regulatory peptide adrenomedullin. Part of this role appears to be protection of adrenomedullin from proteolytic degradation. The binding interaction is unusual and merits further investigation. Adrenomedullin has potential therapeutic uses in diseases affecting the vasculature, and factor H has been administered with adrenomedullin in some animal models of disease.

Topical Docosahexaenoic Acid (DHA) Accelerates Skin Wound Healing in Rats and Activates GPR120

Background:

The development of methods for improving skin wound healing may have an impact on the outcomes of a number of medical conditions. The topical use of polyunsaturated fatty acids (PUFAs) can accelerate skin wound healing through mechanisms that involve, at least in part, the modulation of inflammatory activity.

Purpose:

We evaluated whether G-protein-coupled receptor 120 (GPR120), a recently identified receptor for docosahexaenoic acid (DHA) with anti-inflammatory activity, is expressed in the skin and responds to topical DHA.

Method:

Male Wistar rats were submitted to an 8.0-mm wound on the back and were immediately administered a topical treatment of a solution containing 30 μM of DHA once a day. The healing process was photodocumented, and tissues were collected on Days 5, 9, and 15 for protein and RNA analyses and histological evaluation.

Results:

GPR120 was expressed in the intact skin and in the wound. Keratinocytes expressed the most skin GPR120, while virtually no expression was detected in fibroblasts. Upon DHA topical treatment, wound healing was significantly accelerated and was accompanied by the molecular activation of GPR120, as determined by its association with β-arrestin-2. In addition, DHA promoted a reduction in the expression of interleukin (IL) 1β and an increase in the expression of IL-6. Furthermore, there was a significant increase in expression of transforming growth factor β (TGF-β) and the keratinocyte marker involucrin.

Discussion:

Topical DHA improved skin wound healing. The activation of GPR120 is potentially involved in this process.

A deficiency in cold-inducible RNA-binding protein accelerates the inflammation phase and improves wound healing

Chronic or non-healing wounds are a major concern in clinical practice and these wounds are mostly associated with diabetes, and venous and pressure ulcers. Wound healing is a complex process involving overlapping phases and the primary phase in this complex cascade is the inflammatory state. While inflammation is necessary for wound healing, a prolonged inflammatory phase leads to impaired healing. Cold-inducible RNA-binding protein (CIRP) belongs to a family of cold-shock proteins that are expressed in high levels under stress conditions. Recently, we demonstrated that a deficiency in CIRP led to decreased inflammation and mortality in an experimental model of hemorrhagic shock. Thus, we hypothesized that a deficiency in CIRP would accelerate the inflammatory phase and lead to an improvement in cutaneous wound healing. In this study, to examine this hypothesis, a full-thickness wound was created on the dorsum of wild-type (WT) and CIRP-/- mice. The wound size was measured every other day for 14 days. The wound area was significantly decreased in the CIRP-/- mice by day 9 and continued to decrease until day 14 compared to the WT mice. In a separate cohort, mice were sacrificed on days 3 and 7 after wounding and the skin tissues were harvested for histological analysis and RNA measurements. On day 3, the mRNA expression of tumor necrossis factor (TNF)-α in the skin tissues was increased by 16-fold in the WT mice, whereas these levels were increased by 65-fold in the CIRP-/- mice. Of note on day 7, while the levels of TNF-α remained high in the WT mice, these levels were significantly decreased in the CIRP-/- mice. The histological analysis of the wounded skin tissue indicated an improvement as early as day 3 in the CIRP-/- mice, whereas in the WT mice, infiltrated immune cells were still present on day 7. On day 7 in the CIRP-/- mice, Gr-1 expression was low and CD31 expression was high, whereas in the WT mice, Gr-1 expression was high and CD31 expression was low, indicating that the CIRP-/- mice have already moved into the angiogenesis and tissue formation phase, whereas the WT mice were still in the inflammatory state. These data collectively suggest that a deficiency in CIRP accelerates the wound healing process.