Botulinum toxin type A inhibits M1 macrophage polarization by deactivation of JAK2/STAT1 and IκB/NFκB pathway and contributes to scar alleviation in aseptic skin wound healing

The non-neuronal and non-muscular effects of botulinum toxin type A (BTXA) on scar reduction has been discovered. This study was designed to investigate the effects of BTXA on macrophages polarization during the early stage of skin repair. A skin defect model was established on the dorsal skin of SD rats. BTXA was intracutaneous injected into the edge of wound immediately as the model was established. Histological examinations were performed on scar samples. Raw 264.7 was selected as the cell model of recruited circulating macrophages, and was induced for M1 polarization by LPS. Identify the signaling pathways that primarily regulated M1 polarization and respond to BTXA treatment. Application of BTXA at early stage of injury significantly reduced the scar diameter without delaying wound closure. BTXA treatment improved fiber proliferation and arrangement, and inhibited angiogenesis in scar granular tissue. The number of M1 macrophages and the levels of pro-inflammation were decreased after treated with BTXA in scar tissues. LPS activated JAK2/STAT1 and IκB/NFκB pathways were downregulated by BTXA, as well as LPS induced M1 polarization. At early stage of skin wound healing, injection of BTXA effectively reduced the number of M1 macrophages and the levels of pro-inflammatory mediators which contributes to scar alleviation. BTXA resisted the M1 polarization of macrophages induced by LPS via deactivating the JAK2/STAT1 and IκB/NFκB pathways.

PTEN hinders the formation of scars by regulating the levels of proteins in the extracellular matrix and promoting the apoptosis of dermal fibroblasts through Bcl-xL

Hypertrophic scar (HS) is a dermatological condition characterized by an excessive accumulation of proteins in the extracellular matrix (ECM) and an elevated cell count. The development of HS is thought to be linked to the disruption of dermal fibroblast proliferation and apoptosis. The processes of cell proliferation and apoptosis are notably influenced by PTEN. However, the precise mechanisms by which PTEN regulates hypertrophic scar fibroblasts (HSFs) and its overall role in scar formation are still not fully understood. The objective of this study was to investigate the influence of PTEN on hypertrophic scars(HS) and its function in the regulation of scar formation, with the aim of identifying a pivotal molecular target for scar treatment. Our results demonstrate that the overexpression of PTEN (AdPTEN) significantly suppressed the expression of type I collagen (Col I), type III collagen (Col III), and alpha smooth muscle actin (α-SMA) in HSFs. Furthermore, it was observed that the introduction of AdPTEN resulted in the suppression of Bcl-xL expression, which consequently led to an increase in the apoptosis of HSFs. Similarly, in the inhibition of collagens expression and subsequent increase in HSF apoptosis were also observed upon silencing Bcl-xL (sibcl-xL). Additionally, the in vitro model demonstrated that both AdPTEN and sibcl-xL were effective in reducing the contraction of FPCL. The findings of our study provide validation for the role of PTEN in inhibiting the development of hypertrophic scars (HS) by modulating the expression of extracellular matrix (ECM) proteins and promoting apoptosis in hypertrophic scar fibroblasts (HSFs) via Bcl-xL. These results indicate that PTEN and Bcl-xL may hold promise as potential molecular targets for therapeutic interventions aimed at managing hypertrophic scars.

Copper ion/gallic acid MOFs-laden adhesive pomelo peel sponge effectively treats biofilm-infected skin wounds and improves healing quality

Bacterial infection and scar formation remain primary challenges in wound healing. To address these issues, we developed a decellularized pomelo peel (DPP) functionalized with an adhesive PVA-TSPBA hydrogel and antibacterial gallic acid/copper MOFs. The hybrid wound dressing demonstrates favorable biocompatibility. It does not impede the proliferation of fibroblasts or immune cells and can stimulate fibroblast migration, endothelial angiogenesis, and M2 macrophage polarization. Additionally, the dressing can scavenge reactive oxygen species (ROS) and provide antioxidant effects. Furthermore, DPP + MOF@Gel effectively inhibits the viability of S. aureus and E. coli in vitro and in vivo. The histological observations revealed enhanced granulation tissue formation, re-epithelialization, and angiogenesis in the DPP + MOF@Gel group compared to other groups. The local immune response also shifted from a pro-inflammatory to a pro-regenerative status with DPP + MOF@Gel treatment. The skin incision stitching experiment further exhibits DPP + MOF@Gel could reduce scar formation during wound healing. Taken together, the hybrid DPP + MOF@Gel holds great promise for treating bacteria-infected skin wounds and inhibiting scar formation during wound healing.

IL-10 dependent modulatory effect of regulatory B10 cells on local scar formation following Roux-en-Y choledochojejunostomy in a novel rat model

Choledochojejunostomy has been common surgical treatment of biliary tract disease. Scar formation at anastomotic often results in postoperative complications associated with bleak post-operative recovery, in which local inflammation may be a potential target to modulate local scar formation. This study investigated the effect of regulatory B10 cells on local scar formation through interleukin-10 signal pathway following Roux-en-Y choledochojejunostomy (RCJS) in a novel rat model. Sprague-Dawley (SD) rats with RCJS were randomly divided into blank group, experimental group, IL-10 blocking group, control group, and received different interventions and duration. Injected through dorsal vein of penis, rats in different groups were treated respectively according to scheme. These interventions were performed during surgery, on 1st day, and 2nd day after surgery. Related indexes, including blood examination, specimen tissue of anastomotic detection, were recorded and compared in different interventional groups. Rats in experimental groups had more rapid recovery in liver function and inflammatory index, and higher in IL-10 level. Flow cytometry analysis showed that rats in experimental groups had highest content of B10 cells and lowest content of CD4+CD25- T cells in peripheral blood. Wider anastomotic by macroscopical observation, and slighter proliferation of collagen fiber and smooth muscle fiber, lower α-SMA and TGF-β1 levels by pathological staining were detected in experimental groups. Higher expression of the IL-10 gene and lower expression of TGF-β1 at anastomotic were detected in experimental groups. B10 cells may relieve local inflammation of anastomotic following RCJS in rats through IL-10-dependent modulatory effect, and improve local scar formation.

Extracellular vesicles modulate key signalling pathways in refractory wound healing

Chronic wounds are wounds that cannot heal properly due to various factors, such as underlying diseases, infection or reinjury, and improper healing of skin wounds and ulcers can cause a serious economic burden. Numerous studies have shown that extracellular vesicles (EVs) derived from stem/progenitor cells promote wound healing, reduce scar formation and have significant advantages over traditional treatment methods. EVs are membranous particles that carry various bioactive molecules from their cellular origins, such as cytokines, nucleic acids, enzymes, lipids and proteins. EVs can mediate cell-to-cell communication and modulate various physiological processes, such as cell differentiation, angiogenesis, immune response and tissue remodelling. In this review, we summarize the recent advances in EV-based wound healing, focusing on the signalling pathways that are regulated by EVs and their cargos. We discuss how EVs derived from different types of stem/progenitor cells can promote wound healing and reduce scar formation by modulating the Wnt/β-catenin, phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin, vascular endothelial growth factor, transforming growth factor β and JAK-STAT pathways. Moreover, we also highlight the challenges and opportunities for engineering or modifying EVs to enhance their efficacy and specificity for wound healing.

Systematic review of molecular pathways in burn wound healing

Depending on extent and depth, burn injuries and resulting scars may be challenging and expensive to treat and above all heavily impact the patients' lives. This systematic review represents the current state of knowledge on molecular pathways activated during burn wound healing. All currently known molecular information about gene expression and molecular interactions in mammals has been summarized. An ample interaction of regenerative cytokines, growth factors, ECM-regenerative molecules and proinflammatory immune response became apparent. We identified three molecules to be most often involved in the pathways: TGFB1, ACTA1 and COL1A1. Yet, other factors including FLII, AKT1 and miR-145 were shown to play pivotal roles in burn wound healing as well. This systematic review helps to explain the fundamental molecular proceedings participating in burn wound healing. A number of new molecular interactions and functional connections were identified yielding intriguing new research targets. An interactive version of the first network about molecular pathways and interactions during burn wound healing is provided in the online edition and on WikiPathways.

Nano drug delivery systems: a promising approach to scar prevention and treatment

Scar formation is a common physiological process that occurs after injury, but in some cases, pathological scars can develop, leading to serious physiological and psychological effects. Unfortunately, there are currently no effective means to intervene in scar formation, and the structural features of scars and their unclear mechanisms make prevention and treatment even more challenging. However, the emergence of nanotechnology in drug delivery systems offers a promising avenue for the prevention and treatment of scars. Nanomaterials possess unique properties that make them well suited for addressing issues related to transdermal drug delivery, drug solubility, and controlled release. Herein, we summarize the recent progress made in the use of nanotechnology for the prevention and treatment of scars. We examine the mechanisms involved and the advantages offered by various types of nanomaterials. We also highlight the outstanding challenges and questions that need to be addressed to maximize the potential of nanotechnology in scar intervention. Overall, with further development, nanotechnology could significantly improve the prevention and treatment of pathological scars, providing a brighter outlook for those affected by this condition.

Implications of microglial heterogeneity in spinal cord injury progression and therapy

Microglia are widely distributed in the central nervous system (CNS), where they aid in the maintenance of neuronal function and perform key auxiliary roles in phagocytosis, neural repair, immunological control, and nutrition delivery. Microglia in the undamaged spinal cord is in a stable state and serve as immune monitors. In the event of spinal cord injury (SCI), severe changes in the microenvironment and glial scar formation lead to axonal regeneration failure. Microglia participates in a series of pathophysiological processes and behave both positive and negative consequences during this period. A deep understanding of the characteristics and functions of microglia can better identify therapeutic targets for SCI. Technological innovations such as single-cell RNA sequencing (Sc-RNAseq) have led to new advances in the study of microglia heterogeneity throughout the lifespan. Here,We review the updated studies searching for heterogeneity of microglia from the developmental and pathological state, survey the activity and function of microglia in SCI and explore the recent therapeutic strategies targeting microglia in the CNS injury.

Insight into the role of DPP-4 in fibrotic wound healing

Wound healing is a complex and long-term process consisting of hemostasis, inflammation, proliferation, and maturation/remodeling. These four stages overlap and influence each other; they affect wound healing in different ways, and if they do not function perfectly, they may cause scarring, proliferative scarring and keloid formation. A therapeutic target affecting wound healing in multiple ways will help the healing process proceed more effectively. DPP-4/CD26 is a multifunctional dimorphic glycoprotein widely distributed on the surface of a variety of cells, including fibroblasts and keratin-forming cells. It has been found to affect periwound inflammation, re-epithelialization, extracellular matrix secretion and skin fibrosis and is a potential target for promoting wound healing and inhibiting scar formation. After presenting a brief introduction of the wound healing process and DPP-4/CD26, this paper summarizes the effects of DPP-4/CD26 on cells involved in different stages of wound healing and discusses the feasibility of DPP-4/CD26 as a multifunctional target for the treatment of wound healing and inhibition of scar formation.

Conditioned media derived from human fetal progenitor cells improves skin regeneration in burn wound healing

Stem cells are known to have excellent regenerative ability, which is primarily facilitated by indirect paracrine factors, rather than via direct cell replacement. The regenerative process is mediated by the release of extracellular matrix molecules, cytokines, and growth factors, which are also present in the media during cultivation. Herein, we aimed to demonstrate the functionality of key factors and mechanisms in skin regeneration through the analysis of conditioned media derived from fetal stem cells. A series of processes, including 3D pellet cultures, filtration and lyophilization is developed to fabricate human fetal cartilage-derived progenitor cells-conditioned media (hFCPCs-CM) and its useful properties are compared with those of human bone marrow-derived MSCs-conditioned media (hBMSCs-CM) in terms of biochemical characterization, and in vitro studies of fibroblast behavior, macrophage polarization, and burn wound healing. The hFCPCs-CM show to be devoid of cellular components but to contain large amounts of total protein, collagen, glycosaminoglycans, and growth factors, including IGFBP-2, IGFBP-6, HGF, VEGF, TGF β3, and M-CSF, and contain a specific protein, collagen alpha-1(XIV) compare with hBMSCs-CM. The therapeutic potential of hFCPCs-CM observes to be better than that of hBMSCs-CM in the viability, proliferation, and migration of fibroblasts, and M2 macrophage polarization in vitro, and efficient acceleration of wound healing and minimization of scar formation in third-degree burn wounds in a rat model. The current study shows the potential therapeutic effect of hFCPCs and provides a rationale for using the secretome released from fetal progenitor cells to promote the regeneration of skin tissues, both quantitatively and qualitatively. The ready-to-use product of human fetal cartilage-derived progenitor cells-conditioned media (hFCPCs-CM) are fabricated via a series of techniques, including a 3D culture of hFCPCs, filtration using a 3.5 kDa cutoff dialysis membrane, and lyophilization of the CM. hFCPCs-CM contains many ECM molecules and biomolecules that improves wound healing through efficient acceleration of M2 macrophage polarization and reduction of scar formation.

Effects of Placenta-Derived Human Amniotic Epithelial Cells on the Wound Healing Process and TGF-β Induced Scar Formation in Murine Ischemic-Reperfusion Injury Model

BACKGROUND

Pressure ulcers (PUs), a result of ischemic reperfusion (IR) injuries, are prevalent skin problems which show refractoriness against standard therapeutic approaches. Besides, scar formation is a critical complication of ulcers that affects functionality and the skin's cosmetic aspect. The current study aimed to investigate the effects of placenta-derived human amniotic epithelial cells (hAECs), as important agents of regenerative medicine and stem cell therapy, on accelerating the healing of IR ulcers in mice. We also evaluated the effects of these cells on reducing the TGFβ-induced scar formation.

METHODS

Male Balb/c mice at the age of 6-8 weeks were subjected to three IR cycles. Afterward, the mice were divided into three experimental groups (n = 6 per group), including the control group, vehicle group, and hAECs treatment group. Mice of the treatment group received 100 μL of fresh hAECs 1 × 10⁶ cell/ml suspension in PBS. Afterward, mice were assessed by histological, stereological, molecular, and western blotting techniques at 3, 7, 14, and 21 days after wounding.

RESULTS

The histological and stereological results showed the most diminutive scar formation and better healing in the hAECs treated group compared to control group. Furthermore, our results demonstrated that the expression level of Col1A1 on days 3, 14, and 21 in the hAECs treated group was significantly lower than control. Additionally, injection of hAECs significantly reduced the expression level of Col3A1 on days 3, 7, and 21 while increased Col3A1 on the day 14. Otherwise, in the hAECs treated group, the expression levels of VEGFA on days 7 and 14 were higher, which showed that hAECs could promote angiogenesis and wound healing. Also, cell therapy significantly lowered the protein levels of TGF-β1 on day 14, while the protein level of TGF-β3 on day 14 was significantly higher. This data could demonstrate the role of hAECs in scar reduction in IR wounds.

CONCLUSION

These results suggest that hAECs can promote re-epithelialization and wound closure in an animal model of PU. They also reduced scar formation during wound healing by reducing the expression of TGF-β1/ TGF-β3 ratio.

CD73+ adipose-derived stem cells reduce scar formation through PLOD1

Background

Reducing cutaneous scar formation is important for assessing the success of skin wound healing. Although it is generally accepted that adipose-derived mesenchymal stem cells (AMSCs) have substantial therapeutic potential, efforts are continuously made to improve the outcome of AMSC therapy. Post-transcriptional suppression of procollagen-lysine 1, 2-oxoglutarate 5-dioxygenase 1 (PLOD1) in AMSCs has been shown to greatly reduce scar formation during skin wound healing, likely through modulating macrophage polarization. In the present study, we tested whether a CD73⁺ subpopulation of AMSCs could reduce scar formation compared with CD73^– AMSCs.

Methods

The gene profile of CD73⁺ versus CD73^– AMSCs was obtained from a validated public database, GSE167219. AMSCs were isolated from adipose tissue surrounding the groin of mice, after which CD73⁺ versus CD73^– AMSCs were sorted using flow cytometry. PLOD1 levels were determined in CD73⁺ versus CD73^– AMSCs. Then, PLOD1 in CD73^– AMSCs was depleted by a short-hair interfering RNA against PLOD1 (sh-PLOD1), while PLOD1 in CD73⁺ AMSCs was increased by expression of a PLOD1 transgene. A blade was used to induce a skin injury on the middle back of the mice. Either CD73⁺ AMSCs or CD73⁺ PLOD1 AMSCs or CD73^– AMSCs or CD73^– sh-PLOD1 AMSCs were intravenously transplanted into the injured region of the mice. Fibrosis and the underlying mechanisms were investigated. Co-immunoprecipitation was performed to evaluate interaction between CD73 and PLOD1.

Results

CD73⁺ AMSCs expressed significantly lower levels of PLOD1, a potent stimulator of fibrosis, compared with CD73^– AMSCs. Transplantation of CD73⁺ AMSCs generated significantly reduced fibrosis at the skin injury site compared with CD73^– AMSCs. However, expression of PLOD1 in CD73⁺ AMSCs abolished its advantageous effects on fibrosis reduction, while depletion of PLOD1 in CD73^– AMSCs improved the outcome of fibrosis to the levels of transplantation of CD73⁺ AMSCs. Co-immunoprecipitation showed no direct protein interaction between CD73 and PLOD1.

Conclusions

CD73⁺ AMSCs are a subgroup of AMSCs with better therapeutic effects on wound healing, and can inhibit scar formation through reduced PLOD1 in an indirect manner.

Posttranscriptional control of PLOD1 in adipose-derived stem cells regulates scar formation through altering macrophage polarization

Background

The level of cutaneous scar formation is a critical parameter to determine the success of skin wound healing. Adipose-derived mesenchymal stem cells (AMSCs) have been applied to improve treatment of cutaneous injury with the purpose of reducing scar formation.

Methods

The levels of procollagen-lysine 1,2-oxoglutarate 5-dioxygenase 1 (PLOD1) were assessed at scar sites. Then, PLOD1 in AMSCs was depleted by either expression of a PLOD1-specific short-hair interfering RNA (shPLOD1) or by expression of microRNA-449 (miR-449) that targets and suppresses protein translation of PLOD1 through 3 prime untranslated region (3'-UTR) interfering. For induction of skin injury, a blade cut of 1.5-cm long and 2-mm thick was made on the middle back of the mice. Transplantation of either AMSCs-shPLOD1 or AMSCs-miR-449 into the injured region of the mice was performed via tail vein injection. The fibrosis as well as underlying mechanisms were assessed.

Results

The AMSCs expressed high levels of PLOD1, a potent stimulator of fibrosis. We knocked down PLOD1 in AMSCs by expression of either shPLOD1 or miR-449. Transplantation of either AMSCs-shPLOD1 or AMSCs-miR-449 significantly reduced the fibrotic process in the injured region of the mice to a similar degree. Mechanistically, transplantation of either AMSCs-shPLOD1 or AMSCs-miR-449 shifted macrophage polarization from M2 to M1-like and reduced both reactive oxygen species (ROS) and activation of myofibroblasts from fibroblasts.

Conclusions

Suppression of PLOD1 levels in AMSCs either directly by shPLOD1 or indirectly by miR-449 may substantially improve the anti-fibrotic potential of AMSCs during wound healing, likely through altering macrophage polarization.

Apical Resection and Cryoinjury of Neonatal Mouse Heart

Neonatal mouse hearts have a regenerative capacity similar to adult zebrafish. Different cardiac injury models have been established to investigate the regenerative capacity of neonatal mouse hearts, including ventricular amputation, cryoinjury, and ligation of a major coronary artery. While the ventricular resection model can be utilized to study how tissue forms and regenerates de novo, cryoinjury and coronary artery ligation are methods that might better mimic myocardial infarction by creating tissue damage and necrosis as opposed to the removal of healthy tissue in the ventricular amputation model. Here we describe methods of creating ventricular resection and cardiac cryoinjury in newborn mice.

Cell sheets using human amniotic fluid stem cells reduce tissue fibrosis in murine full-thickness skin wounds

The use of mesenchymal stem cell sheets is a promising strategy for skin regeneration. The injection of dissociated human amniotic fluid stem cells (hAFSCs) was recently found to accelerate cutaneous wound healing with reduced fibrotic scarring, similar to fetal wound healing. However, the use of hAFSCs in applications of cell sheet technology remains limited. The aim of this study was to determine the in vivo efficacy of in vitro-cultured hAFSC sheets in wound healing. The cell sheets were characterized by immunohistochemistry and RT-qPCR and grafted onto full-thickness wounds in BALB/c mice. The wound size was measured, and re-epithelialization, granulation tissue area, and collagen content of the regenerated wound were analyzed histologically. Although the hAFSC sheet contained abundant extracellular matrix molecules and expressed high levels of anti-fibrotic mediators, its grafting did not affect wound closure or the size of the granulation tissue area. In contrast, the organization of type I collagen bundles in the regenerated wound was markedly reduced, while the levels of type III collagen were increased after implantation of the hAFSC sheet. These results suggest that hAFSC sheets can exert anti-fibrotic properties without delaying wound closure.

Bidirectional regulation of i-type lysozyme on cutaneous wound healing

OBJECTIVE

This study aimed to assess the effect and mechanism of i-type lysozyme on cutaneous wound healing animal model and Multiple cell models both in vivo and in vitro.

METHODS

Therefore, to evaluate its regenerative efficacy on wound healing process, we daily applied i-type lysozyme on murine full-thickness excisional wounds. After sacrifice on indicated days, skin tissues around surgical defects were harvested and assessed for re-epithelialization, granulation tissue formation, neovascularization and remodeling. To elucidate the underlying mechanisms, i-type lysozyme was analyzed for its tissue regenerative potency on the proliferation, invasion, migration and tube formation against keratinocytes, fibroblasts and endothelial cells. Antioxidant and antimicrobial experiments were also conducted to elucidate protective ability of i-type lysozyme to wound bed.

RESULTS

It displayed excellent bi-directional regulation in wound repair, with significant acceleration of epidermal and dermal regeneration as well as the efficient attenuation of excessive collagen deposition and fibrosis in the surgical lesion. I-type lysozyme treatment augmented the proliferation and migration of HaCaT, NIH 3T3 and HUVECs, enhanced the invasion of HaCaT and HUVECs as well as accelerated tube formation of HUVECs. Additionally, it significantly recovered the proliferation of H₂O₂-damaged cells, whereas represented no microbicidal effect under effective concentration of wound healing.

CONCLUSION

Our findings demonstrate the bi-directional regulation of i-type lysozyme in wound healing process through promoting tissue regeneration while hampering scar formation, implying that it is a promising therapeutic agent for wound repair.

A Review of the Contribution of Mast Cells in Wound Healing: Involved Molecular and Cellular Mechanisms

Mast cells (MCs), apart from their classic role in allergy, contribute to a number of biologic processes including wound healing. In particular, two aspects of their histologic distribution within the skin have attracted the attention of researchers to study their wound healing role; they represent up to 8% of the total number of cells within the dermis and their cutaneous versions are localized adjacent to the epidermis and the subdermal vasculature and nerves. At the onset of a cutaneous injury, the accumulation of MCs and release of proinflammatory and immunomodulatory mediators have been well documented. The role of MC-derived mediators has been investigated through the stages of wound healing including inflammation, proliferation, and remodeling. They contribute to hemostasis and clot formation by enhancing the expression of factor XIIIa in dermal dendrocytes through release of TNF-α, and contribute to clot stabilization. Keratinocytes, by secreting stem cell factor (SCF), recruit MCs to the site. MCs in return release inflammatory mediators, including predominantly histamine, VEGF, interleukin (IL)-6, and IL-8, that contribute to increase of endothelial permeability and vasodilation, and facilitate migration of inflammatory cells, mainly monocytes and neutrophils to the site of injury. MCs are capable of activating the fibroblasts and keratinocytes, the predominant cells involved in wound healing. MCs stimulate fibroblast proliferation during the proliferative phase via IL-4, vascular endothelial growth factor (VEGF), and basic fibroblast growth factor (bFGF) to produce a new extracellular matrix (ECM). MC-derived mediators including fibroblast growth factor-2, VEGF, platelet-derived growth factor (PDGF), TGF-β, nerve growth factor (NGF), IL-4, and IL-8 contribute to neoangiogenesis, fibrinogenesis, or reepithelialization during the repair process. MC activation inhibition and targeting the MC-derived mediators are potential therapeutic strategies to improve wound healing through reduced inflammatory responses and scar formation.

Approaches to Reducing Risk in Rhytidectomy Surgery

Please verify edit, "complications could". All operations have sequelae. These are to be expected and must be told to patients. With surgery, the risk of complications is ever-present albeit infrequent. Facelift surgeons have ethical and intellectual duties to fully inform patients of these risks. Surgeons also must have strategies to reduce the risks, knowledge in how to manage each potential risk, and ability to help patients understand how complications could have occurred and how to cope with them. This article discusses facelift complications, the causes thereof, and how to assess a problem, manage each complication, and comfort a distraught patient.

Advancements to the Axolotl Model for Regeneration and Aging

Loss of regenerative capacity is a normal part of aging. However, some organisms, such as the Mexican axolotl, retain striking regenerative capacity throughout their lives. Moreover, the development of age-related diseases is rare in this organism. In this review, we will explore how axolotls are used as a model system to study regenerative processes, the exciting new technological advancements now available for this model, and how we can apply the lessons we learn from studying regeneration in the axolotl to understand, and potentially treat, age-related decline in humans.

TGF-β-induced fibrotic stress increases G-quadruplex formation in human fibroblasts

Scar formation after wound healing is a major medical problem. A better understanding of the dynamic nuclear architecture of the genome during wound healing could provide insights into the underlying pathophysiology and enable novel therapeutic strategies. Here, we demonstrate that TGF-β-induced fibrotic stress increases formation of the dynamic secondary DNA structures called G-quadruplexes in skin fibroblasts, which is coincident with increased expression of collagen 1. This G-quadruplex formation is attenuated by a small molecule inhibitor of intracellular Ca²⁺ influx and an anti-fibrotic compound. In addition, we identify G-quadruplex-forming sequences in the promoter region of COL1A1, which encodes collagen 1, and confirm their ability to form G-quadruplex structures under physiologically relevant conditions. Our findings reveal a link between G-quadruplexes and scar formation that may lead to novel therapeutic interventions.

Modified Cortex Mori Capsules improving the successful rate of functional filtering blebs after reclinical glaucoma filtering surgery

BACKGROUND

The major reason for filtering bleb failure or scarring of the bleb site is due to excessive scarring after glaucoma filtration surgery in the clinic. Traditional Chinese medicine has preeminence in the prevention of fibrosis formation through the regulation of systemic circulation and improvement of the properties of the inflammatory cells in the blood.

AIM

To examine the clinical efficacy of using the Modified Cortex Mori Capsules (MCMC; Chinese name: Jiawei Sangbaipi Capsules) in the success rate of functional filtering blebs after glaucoma filtering surgery in clinical patients.

METHODS

Sixty resurgery glaucoma patients were randomly divided into two groups: 30 patients in surgery with the placebo group and 30 patients in surgery with the MCMC group. Patients took either the placebo or the MCMC 2 wk before and after surgery. Postoperative morphology and function filtering bleb, visual acuity, intraocular pressure, postoperative complications, the success rate of filtration surgery and clinical efficacy were observed.

RESULTS

Fifty patients completed the study. The percentage of functional filtering blebs in the surgery plus MCMC group was 84% at 6 mo after surgery, which was higher than surgery plus placebo group (64%, P < 0.05). The surgical success rate in the MCMC and placebo groups were 79% ± 8.3% and 57% ± 10.6% respectively (P < 0.05). The visual acuity, intraocular pressure and the postoperative complications in the two groups had no significant differences.

CONCLUSION

Glaucoma filtering surgery while taking MCMC not only reduced excessive scar formation and increased the success rate of functional filtering blebs but also improved the success of glaucoma filtration operations.

Differential Gamma-Synuclein Expression in Acute and Chronic Retinal Ganglion Cell Death in the Retina and Optic Nerve

We used genetic naturally occurring glaucoma (DBA/2J) and experimentally induced optic nerve crush (ONC) as models to study gamma-synuclein expression change in retinal ganglion cells and optic nerves. Gene chip microarray analysis demonstrated downregulated expression of the gamma-synuclein gene in DBA/2J mice as they developed age-associated glaucoma with concomitant with retinal ganglion cell loss. Real-time PCR, Western blot, and immunostaining results confirmed that the expression of gamma-synuclein at the mRNA and protein level was significantly reduced in the retinas and optic nerves of aged DBA/2J mice. We also observed similar reduced expression of gamma-synuclein in the retinas from mice after optic nerve crush. Surprisingly, the expression of gamma-synuclein was increased in optic nerves after crush. This is the first study demonstrating gamma-synuclein-expressing cells accumulate in the optic nerve crush site. Gamma-synuclein was found in axons colocalizing largely with neurofilaments in control mice without injury but was found inside cells within the scar in the crush site. Gamma-synuclein expression is predominantly expressed at the optic nerve crush site associated with CD68⁺ macrophage-like cells, not GFAP-expressing astroglial cells, suggesting gamma-synuclein expression is associated with glial scar formation inhibitory to optic nerve regeneration. We propose gamma-synuclein labels macrophage-like cells recruited to the site of acute optic nerve injury.

A New Grading of Epidural Hematoma or Scar Formation after Posterior Cervical Spine Surgery: Evaluation of Perioperative Related Factors, Distributions, and Clinical Outcomes after Surgery

Introduction

The purpose of this study was to evaluate surgical outcomes using a new grading of postoperative epidural hematoma (EH) or epidural scar formation after posterior cervical spine surgery.

Methods

Postoperative EH or epidural scar formation after cervical laminoplasty (LP) or posterior decompression and fusion (PDF) were graded into Grades 1-5 by magnetic resonance imaging at 24 hours, 2 weeks, 6 months, and one year after surgery. The patients were divided into the Mild group (Grades 1-3) and the Severe group (Grades 4, 5). Perioperative factors were compared between the two groups at 24 hours after surgery. Distribution of EH or scar formation was investigated according to two surgeries. The recovery rate of Japanese Orthopedic Association (JOA) scores and the improvements of neck disability index (NDI) were compared between the two groups at one year postoperatively.

Results

Of the postoperative factors, posterior shift of the cervical spinal cord at C4 and C7 significantly differed between the two groups. Patients in the Severe group at 24 hours after surgery (17%) increased to 41% at 2 weeks and subsequently decreased to 16% at 6 months after LP. After PDF, 3% in the Severe group at 24 hours after surgery increased to 15% at 2 weeks and then decreased to 3% at 6 months postoperatively. Only one (3%) patient remained in the Severe group at 1 year after PDF. The recovery rate of JOA score (47.5%) of the patients in the Mild group showed trend larger than that of the Severe group (34.7%) after LP. Preoperative NDI (15.6 points) significantly improved postoperatively to 12.1 points in only the Mild group after LP.

Conclusions

The patterns of distribution of EH or scar formation did not differ between the two surgical methods. The severity of postoperative scar formation related to surgical outcomes after LP.

Immune responses in cardiac repair and regeneration: a comparative point of view

Immediately after cardiac injury, the immune system plays major roles in repair and regeneration as it becomes involved in a number of processes including damage-associated signaling, inflammation, revascularization, cardiomyocyte dedifferentiation and replenishment, and fibrotic scar formation/resolution. Recent studies have revealed that different immune responses occur in the various experimental models capable or incapable of cardiac regeneration, and that harnessing these immune responses might improve cardiac repair. In light of this concept, this review analyzes current knowledge about the immune responses to cardiac injury from a comparative perspective. Insights gained from such comparative analyses may provide ways to modulate the immune response as a potential therapeutic strategy for cardiac disease.

Human amniotic fluid stem cells have a unique potential to accelerate cutaneous wound healing with reduced fibrotic scarring like a fetus

Adult wound healing can result in fibrotic scarring (FS) characterized by excess expression of myofibroblasts and increased type I/type III collagen expression. In contrast, fetal wound healing results in complete regeneration without FS, and the mechanism remains unclear. Amniotic fluid cells could contribute to scar-free wound healing, but the effects of human amniotic fluid cells are not well characterized. Here, we determined the effect of human amniotic fluid stem cells (hAFS) on FS during wound healing. Human amniotic fluid was obtained by amniocentesis at 15-17 weeks of gestation. CD117-positive cells were isolated and defined as hAFS. hAFS (1 × 10⁶) suspended in PBS or cell-free PBS were injected around wounds created in the dorsal region of BALB/c mice. Wound size was macroscopically measured, and re-epithelialization in the epidermis, granulation tissue area in the dermis and collagen contents in the regenerated wound were histologically analyzed. The ability of hAFS to engraft in the wound was assessed by tracking hAFS labeled with PKH-26. hAFS fulfilled the minimal criteria for mesenchymal stem cells. hAFS injection into the wound accelerated wound closure via enhancement of re-epithelialization with less FS. The process was characterized by lower numbers of myofibroblasts and higher expression of type III collagen. Finally, transplanted hAFS were clearly observed in the dermis until day 7 implying that hAFS worked in a paracrine manner. hAFS can function in a paracrine manner to accelerate cutaneous wound healing, producing less FS, a process resembling fetal wound healing.

Extracellular vesicles as modulators of wound healing

Impaired healing of cutaneous wounds and ulcers continues to have a major impact on the quality of life of millions of people. In recent years, the capacity for stem and progenitor cells to promote wound repair has been investigated with evidence that secreted factors are responsible for the observed therapeutic benefits. This review addresses current evidence in support of stem/progenitor cell-derived extracellular vesicles (EVs) as a regenerative therapy for acceleration of wound healing. Encouraging results for local or systemic administration of EVs have been reported in a range of clinically-relevant animal models of cutaneous wounds. Furthermore, a number of plausible mechanisms involving EV-mediated transfer of proteins and RNAs that trigger pro-repair pathways in target cells have been demonstrated experimentally. However, for successful clinical translation in the coming years, further emphasis on standardized experimental protocols, detailed methodological reporting and clear definition of EV-based therapeutic products will be required.

Early intervention by Captopril does not improve wound healing of partial thickness burn wounds in a rat model

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Inhibition of the Renin Angiotensin System does not influence the inflammatory reaction in the burn wounds.

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Inhibition of the Renin Angiotensin System early during burn wound healing does not improve the process.

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Inhibition of the Renin Angiotensin System early during burn wound healing does not reduce scar formation.

The Renin Angiotensin System is involved in fibrotic pathologies in various organs such as heart, kidney and liver. Inhibition of this system by angiotensin converting enzyme antagonists, such as Captopril, has been shown beneficial effects on these pathologies. Captopril reduced the inflammatory reaction but also directly influenced the fibrotic process.

Prolonged and excessive inflammatory response is a major cause of hypertrophic scar formation in burns. We therefore evaluated the effect of Captopril on the healing of partial thickness burn wounds in a rat model.

Partial thickness contact burns were inflicted on the dorsum of the rats. The rats received either systemic or local treatment with Captopril. The inflammatory reaction and wound healing (scar) parameters were investigated and compared to control animals.

In this study we could not detect positive effects of either administration route with Captopril on the inflammatory reaction, nor on wound healing parameters. The local treatment showed reduced wound closure in comparison to the systemic treatment and the control group.

Early Captopril treatment of burn wounds did not show the beneficial effects that were reported for fibrotic disorders in other tissues. To influence the fibrotic response Captopril treatment at a later time point, e.g. during the remodeling phase, might still have beneficial effects.

Phospholipase Cε deficiency delays the early stage of cutaneous wound healing and attenuates scar formation in mice

This study aimed to investigate the role of phospholipase Cε (PLCε) in the skin wound healing process. PLCε, an effect factor of Ras/Rap small G protein, plays a crucial role in skin inflammation by regulating inflammatory cytokines. Inflammatory responses are closely associated with wound healing. Full-thickness skin wounds were made in the PLCε knockout (KO) and wild-type (WT) mice, and the healing process was analyzed. The macroscopic wound closure rate declined in the PLCε KO mice on days 3, 4, and 5 after wounding, following the decreased expression of interleukin (IL)-6, chemokine (C-X-C motif) ligand (Cxcl)-1, Cxcl-2, and chemokine (C-C motif) ligand (Ccl) 20. The proliferation rate of epidermal keratinocytes was not affected by PLCε, but silencing of PLCε resulted in the delayed migration of keratinocytes. Moreover, the scars were found to be much smaller in the PLCε KO mice than in the WT mice. The mRNA expression of Ccl20, collagen (Col) 6a1, and Col17a1 decreased in the PLCε KO mice. These results were in agreement with a previous hypothesis that PLCε might delay the early stage of cutaneous wound healing by inhibiting the migration of keratinocytes, and decrease the expression of Col6a1, Col17a1, and Ccl20 by inhibiting the inflammatory response to reduce scar formation. This study shed light on a novel role of PLCε in wound healing and provided new therapeutic approaches to target PLCε for diminishing scar formation after injury.

Novel Insights on Understanding of Keloid Scar: Article Review

Keloid scar, dermal benign fibro-proliferative growth that extends outside the original wound and invades adjacent dermal tissue due to extensive production of extracellular matrix, especially collagen, which caused by over expression of cytokines and growth factors. Although many attempts were made to understand the exact pathophysiology and the molecular abnormalities, the pathogenesis of keloid scar is yet to be determined. Even though there are several treatment options for keloid scars include combination of medical and surgical therapies like combination of surgical removal followed by cryotherapy or intralesional steroid therapy, the reoccurrence rate is still high despite the present treatment. In this review, PubMed, clinical key and Wright State Library web site have been used to investigate any update regarding Keloid disease. We used Keloid, scar formation, hypertrophic scar and collagen as key words. More than 40 articles have been reviewed. This paper reviews literature about keloid scar formation mechanism, the most recent therapeutic options including the ones under research.

Protective effects of batroxobin on a nigrostriatal pathway injury in mice

Traumatic brain injury triggers a series of damaged processes, such as neuronal death and apoptosis, inflammation and scar formation, which contribute to evolution of brain injury. The present study investigated the neuroprotective effects of batroxobin, a drug widely used clinically for ischemia, in a nigrostriatal pathway injury model. Mice subjected to the nigrostriatal pathway injury were injected with batroxobin (30 BU/kg) or vehicle immediately after injury. The behavioral studies showed that batroxobin could improve the motor function in injured mice in long term. Batroxobin also reduced neuronal apoptosis and inflammation at the acute stage. Moreover, administration of batroxobin attenuated the scar formation and reduced the lesion size at 4 and 14days after brain injury. These results suggest that batroxobin has beneficial effects on the nigrostriatal pathway injury, indicating a potential clinical application.

MiR-1908 promotes scar formation post-burn wound healing by suppressing Ski-mediated inflammation and fibroblast proliferation

The cell biological basis for scar formation is mainly via excessive fibroblast proliferation accompanied by hypernomic Col I accumulation and inflammation. The role of miR-1908 in scar formation has not been investigated. In this study, we found that miR-1908 expression was inversely associated with the scar suppressor Ski in normal, burn-wounded, healing and scar dermal tissues in humans. Bioinformatics and luciferase reporter gene assays confirmed that miR-1908 targeted the 3'UTR region of Ski mRNA and suppressed Ski expression. Next, human scar epidermal fibroblasts were isolated and the miR-1908 oligonucleotide mimic and inhibitor were respectively transfected into the cells. Western blot analysis proved that Ski expression was sharply reduced by the miR-1908 mimic. MTT and Cell Counting Kit-8 analyses showed that miR-1908 mimic transfection promoted cell proliferation. Simultaneously, data on real-time qPCR analysis indicated that expression of the fibrotic master gene TGF-β1, Ski-suppressing gene Meox2, Col I and proinflammatory markers IL-1α and TNF-α, were all significantly upregulated. In contrast, the miR-1908 inhibitor had a completely opposite effect on cell proliferation and gene expression. The mimic and inhibitor were locally injected into rats with abdominal burn-wounded scars during a 180-day, post-healing experiment. The miR-1908 mimic injection significantly reduced Ski expression, as well as the area, volume and fibrosis of scars in vivo. And, in contrast, the miR-1908 inhibitor injection had an opposite effect to that of the miR-1908 mimic injection. In conclusion, miR-1908 had a positive role in scar formation by suppressing Ski-mediated inflammation and fibroblast proliferation in vitro and in vivo.

Modulation of mesenchymal stem cells with miR-375 to improve their therapeutic outcome during scar formation

Understanding of the mechanism of cutaneous scar formation with the goal of developing potential therapies to promote scar-less wound healing appears to be extremely critical. Mesenchymal stem cells (MSCs) have a demonstrate role in promoting scar-less wound healing. However, recent studies have shown that the function of MSCs may be attenuated due to insufficient activation in vivo. Here, we aimed to increase the activity and functions of MSCs to improve their effects during scar formation. We found that overexpression of microRNA-375 (miR-375) in MSCs significantly decreased the levels of tissue inhibitor of metalloproteinases 1 (TIMP-1) protein, but not mRNA. Mechanistically, miR-375 inhibited TIMP-1 protein translation through binding to the 3'-UTR of the TIMP-1 mRNA in MSCs. Transplantation of miR-375-expressing MSCs significantly reduced the fibrosis in the scar region of the mice, possibly through reduction of reactive oxygen species (ROS), suppression of transition of myofibroblasts from fibroblasts, and increases in hepatic growth factor (HGF). Together, these data suggest that overexpression of miR-375 in MSCs may substantially improve the effects of MSCs on reduction of scar during wound healing. Our study sheds new light on a scar-less wound healing.

Nanolayered siRNA delivery platforms for local silencing of CTGF reduce cutaneous scar contraction in third-degree burns

Wound healing is an incredibly complex biological process that often results in thickened collagen-enriched healed tissue called scar. Cutaneous scars lack many functional structures of the skin such as hair follicles, sweat glands, and papillae. The absence of these structures contributes to a number of the long-term morbidities of wound healing, including loss of function for tissues, increased risk of re-injury, and aesthetic complications. Scar formation is a pervasive factor in our daily lives; however, in the case of serious traumatic injury, scars can create long-lasting complications due to contraction and poor tissue remodeling. Within this report we target the expression of connective tissue growth factor (CTGF), a key mediator of TGFβ pro-fibrotic response in cutaneous wound healing, with controlled local delivery of RNA interference. Through this work we describe both a thorough in vitro analysis of nanolayer coated sutures for the controlled delivery of siRNA and its application to improve scar outcomes in a third-degree burn induced scar model in rats. We demonstrate that the knockdown of CTGF significantly altered the local expression of αSMA, TIMP1, and Col1a1, which are known to play roles in scar formation. The knockdown of CTGF within the healing burn wounds resulted in improved tissue remodeling, reduced scar contraction, and the regeneration of papillary structures within the healing tissue. This work adds support to a number of previous reports that indicate CTGF as a potential therapeutic target for fibrosis. Additionally, we believe that the controlled local delivery of siRNA from ultrathin polymer coatings described within this work is a promising approach in RNA interference that could be applied in developing improved cancer therapies, regenerative medicine, and fundamental scientific research.

Hypoxia enhances the protective effects of placenta-derived mesenchymal stem cells against scar formation through hypoxia-inducible factor-1α

OBJECTIVES

To explore the effect of placenta-derived mesenchymal stem cells on scar formation as well as the underlying mechanism.

RESULTS

The isolated placenta-derived mesenchymal stem cells from mice were distributed in the wounded areas of scalded mouse models, attenuated inflammatory responses and decreased the deposition of collagens, thus performing a beneficial effect against scar formation. Hypoxia enhanced the protective effect of placenta-derived mesenchymal stem cells and hypoxia-inducible factor-1α was involved in the protective effect of placenta-derived mesenchymal stem cells in hypoxic condition.

CONCLUSIONS

Hypoxia enhanced the protective effect of placenta-derived mesenchymal stem cells through hypoxia-inducible factor-1α and PMSCs may have a potential application in the treatment of wound.

Hypoxic conditioned medium of placenta-derived mesenchymal stem cells protects against scar formation

AIMS

Scar formation after wound repair affects people's daily life. Mesenchymal stem cells were reported to have a beneficial role in attenuating the scar formation. In the present study, placenta-derived mesenchymal stem cells (PMSCs) were isolated and the effects of hypoxic conditioned medium of PMSCs on scar formation were explored.

MAIN METHODS

To evaluate the effect of hypoxia on PMSCs, proliferation of PMSCs was detected by trypan blue staining and the HIF-1α level was detected by western blot. Then in vivo scar formation assay was performed and the histopathologic changes were evaluated by HE staining and levels of TGF-β1 and collagen I were detected by quantitative real-time PCR. The IL-10 level was detected by ELISA and then migration of HFF-1 cells was detected by wound healing assay after treatment with IL-10 or IL-10 antibody.

KEY FINDINGS

Our study showed that hypoxic conditioned medium of PMSCs reduced scar formation in vivo and inhibited the proliferation and migration of skin fibroblasts in vitro. Further mechanism study showed that, the level of IL-10 was affected by hypoxia, treatment with IL-10 mimicked the function of hypoxic conditioned medium of PMSCs and inhibition of IL-10 reversed the protective role of hypoxic conditioned medium of PMSCs. Thus, hypoxic conditioned medium of PMSCs may perform the protective role against scar formation through IL-10.

SIGNIFICANCE

Our study reveals a possible mechanism of the protective effect of PMSCs against scar formation and provides evidence for the hypothesis that PMSCs may be a promising therapy for the treatment of wounds.

Studying Human Brain Inflammation in Leptomeningeal and Choroid Plexus Explant Cultures

The meninges (dura, pia and arachnoid) are critical membranes encasing and protecting the brain within the skull. The leptomeninges, which comprise the arachnoid and pia, have many functions beyond brain protection including roles in neurogenesis, fibrotic scar formation and brain inflammation. Similarly, the choroid plexus plays important roles in normal brain function but is also involved in brain inflammation. We have begun studying the role of human leptomeninges and choroid plexus in brain inflammation and leptomeninges in fibrotic scar formation, using human brain derived explant cultures. To study the composition of the cells generated in these explants we undertook immunocytochemical characterisation. Cells, mainly pericytes and meningeal macrophages, emerge from leptomeningeal explants (LME's) and respond to inflammatory mediators by producing inflammatory molecules. LME-derived cells also respond to mechanical injury and cytokines, providing an in vitro human brain model of fibrotic scar formation. Choroid plexus explants (CPE's) generate epithelial cells, pericytes and microglia/macrophages. CPE-derived cells also respond to inflammatory mediators. LME and CPE explants survive and generate cells for many months in vitro and provide a remarkable opportunity to study basic mechanisms of human brain inflammation and fibrosis and to test human-active anti-inflammatory and anti-scarring treatments.

Efficacy and Safety of Sodium Hyaluronate with 1,4-Butanediol Diglycidyl Ether Compared to Sodium Carboxymethylcellulose in Preventing Adhesion Formation after Lumbar Discectomy

OBJECTIVE

Epidural injection of hyaluronic acid may prevent adhesion formation after spine surgery, but the compounds used to stabilize hyaluronidase could interfere with its anti-adhesion effects. The present study was conducted as a clinical trial to evaluate the efficacy and safety of an experimental medical gel in preventing adhesion formation.

METHODS

This study was designed as a multicenter, randomized, double-blind, and comparative controlled clinical trial with an observation period of 6 weeks. Subjects were randomly assigned into two groups: group A with sodium hyaluronate + 1,4-butanediol diglycidyl ether (BDDE) and group B with sodium hyaluronate + sodium carboxymethylcellulose (CMC). Visual analogue scale (VAS) of back and leg pain and the Oswestry disability index (ODI) and scar score ratings were assessed after surgery.

RESULTS

Mean scar grade was 2.37±1.13 in group A and 2.75±0.97 in group B, a statistically significant difference (p=0.012). VAS of back and leg pain and ODI scores decreased significantly from baseline to 3 and 6 weeks postoperatively in both groups (p<0.001). However, VAS and ODI scores were not statistically different between groups A and B at baseline or at 3 and 6 weeks after operation (p>0.3). The number of adverse reactions related to the anti-adhesion gels was not statistically different (p=0.569), but subsequent analysis of nervous adverse reactions showed group B was superior with a statistically difference (p=0.027).

CONCLUSION

Sodium hyaluronate with BDDE demonstrated similar anti-adhesion properties to sodium hyaluronate with CMC. But, care should be used to nervous adverse reactions by using sodium hyaluronate with BDDE.

Chitooligosaccharide Inhibits Scar Formation and Enhances Functional Recovery in a Mouse Model of Sciatic Nerve Injury

Chitooligosaccharide (COS) has been shown to induce fibroblast apoptosis, indicating that it could be used as a material to inhibit scar formation. In the present study, we used a mouse model of sciatic nerve injury (SNI) to determine the role of COS in scar inhibition and functional recovery. The animals were divided into three groups: SNI, SNI + vehicle, and SNI + COS group. We performed a series of functional and histological examinations at ctrl, 0 min, 14 days, and 42 days, including behavioral recovery, percentage of regenerating axons, degree of scar formation, vascular changes, type I and type III collagen ratio, and percentage of demyelinated axons. The SNI + COS group exhibited better recovery of sensory and motor function and less scar formation. Two-photon microscopy showed that the percentage of regenerating axons was highest in the SNI + COS group at 14 and 42 days. Our results suggested that COS can inhibit scar formation and enhance functional recovery by inducing fibroblast death, altering the proportion of different vascular diameters, changing the ratio of type I/type III collagen, and reducing the percentage of demyelinated axons. COS might be a useful drug in the treatment of SNI to reduce scar formation, but additional research is required to clarify the relevant molecular pathways.

Preliminary results in single-step wound closure procedure of full-thickness facial burns in children by using the collagen-elastin matrix and review of pediatric facial burns

BACKGROUND

Management of full-thickness facial burns remains one of the greatest challenges. Controversy exists among surgeons regarding the use of early excision for facial burns. Unfortunately, delayed excision of deeper burns often results in more scarring and subsequent reconstruction becomes more difficult. A collagen-elastin matrix is used to improve the quality of the reconstructed skin, to reduce scarring and to prevent wound contraction. It serves as a foundation for split thickness skin graft and enhances short and long-term results.

AIM

We report the usage of a collagen-elastin matrix during single-step wound closure technique of severe full-thickness facial burns in 15 children with large burned body surface area, and also we review the literature about pediatric facial burns.

RESULTS

There were 15 pediatric patients with severe facial burns, 8 girls and 7 boys ranging in age from 10 months to 12 years, mean age 7 years and 6 months old. The facial burn surface area (FBSA) among the patients includes seven patients with 100%, five with 75%, and three with 50%. The average total body surface area (TBSA) for the patients was 72%, ranging between 50 and 90%. 5 of the patients' admissions were late, more than four days after burns while the rest of the patients were admitted within the first four days (acute admission time). The burns were caused by flame in eight of the patients, bomb blast in four, and scalding in three. All patients were treated by the simultaneous application of the collagen-elastin matrix and an unmeshed split thickness skin graft at Turgut Özal Medical Center, Pediatric Burn Center, Malatya, Turkey. After the treatment only two patients needed a second operation for revision of the grafts. All grafts transplanted to the face survived. The average Vancouver scar scales (VSS) were 2.55±1.42, ranging between one and six, in the first 10 of 15 patients at the end of 6 months postoperatively. VSS measurements of the last 5 patients were not taken since the 6 months postoperative period was not over.

CONCLUSION

In regard to early results, graft quality was close to normal skin in terms of vascularity, elasticity, pliability, texture and color. Esthetic and functional results have been encouraging. This study shows us that the collagen-elastin matrix as a dermal substitute is a useful adjunct, which may result in quick healing with satisfying esthetic and functional results. It also may enhance short and long-term results in after burn facial wound closure in children.

Microarray-based characterization of differential gene expression during vocal fold wound healing in rats

The vocal fold (VF) mucosa confers elegant biomechanical function for voice production but is susceptible to scar formation following injury. Current understanding of VF wound healing is hindered by a paucity of data and is therefore often generalized from research conducted in skin and other mucosal systems. Here, using a previously validated rat injury model, expression microarray technology and an empirical Bayes analysis approach, we generated a VF-specific transcriptome dataset to better capture the system-level complexity of wound healing in this specialized tissue. We measured differential gene expression at 3, 14 and 60 days post-injury compared to experimentally naïve controls, pursued functional enrichment analyses to refine and add greater biological definition to the previously proposed temporal phases of VF wound healing, and validated the expression and localization of a subset of previously unidentified repair- and regeneration-related genes at the protein level. Our microarray dataset is a resource for the wider research community and has the potential to stimulate new hypotheses and avenues of investigation, improve biological and mechanistic insight, and accelerate the identification of novel therapeutic targets.

Early Excision and Grafting versus Delayed Skin Grafting in Burns Covering Less than 15% of Total Body Surface Area; A Non- Randomized Clinical Trial

OBJECTIVE

To compare outcome of patients with burns covering less than 15% of total body surface area(TBSA) undergoing early excision and grafting or delayed skin grafting.

METHOD

This was a non-randomized clinical trial including 54 patients with less than 15% TBSA burn referring to Ghotboddin Hospital of Shiraz. They were assigned to two study groups, each group including 27 patients: the early excision and grafting group (EEG group) and the delayed grafting group (DG group). Patients were followed postoperatively for 6 months. Hospital stay, graft success rate, itching score and scar formation during 6 months of follow-up were recorded and compared between two study groups.

RESULTS

During the study 1 patient was lost to follow-up in early excision and grafting group. Baseline characteristics were comparable between two study groups. The graft success rate was significantly higher in those patients who underwent early excision and grafting when compared to delayed grafting group (96.88% vs. 92.88%; p=0.033). However the length of hospital stay, itching and scar scores were comparable between two study groups after 6 months of follow-up.

CONCLUSION

In patients with burns covering less than 15% TBSA, early excision and grafting is associated with higher graft success rates compared to the delayed excision and grafting. How ever length of hospital stay, itching and scar formation is comparable between the two techniques.

Independent evaluation of the anatomical and behavioral effects of Taxol in rat models of spinal cord injury

The goal of the current manuscript was to replicate published data that show intrathecal infusions of Taxol® (paclitaxel), an anti-neoplastic microtubule stabilizing agent, reduce fibrogliotic scarring caused by a dorsal spinal hemisection (DHx) injury and increase functional recovery and growth of serotonergic axons after moderate spinal contusion injury. These experiments were completed as part of an NIH-NINDS contract entitled "Facilities of Research Excellence in Spinal Cord Injury (FORE-SCI) - Replication". Here, data are presented that confirm the anti-scarring effects of Taxol after DHx injury; however, Taxol did not confer neuroprotection or promote serotonergic axon growth nor did it improve functional recovery in a model of moderate spinal contusion injury. Thus, only partial replication was achieved. Possible explanations for disparate results in our studies and published data are discussed.

Intranasally administered mesenchymal stem cells promote a regenerative niche for repair of neonatal ischemic brain injury

Previous work from our group has shown that intranasal MSC-treatment decreases lesion volume and improves motor and cognitive behavior after hypoxic-ischemic (HI) brain damage in neonatal mice. Our aim was to determine the kinetics of MSC migration after intranasal administration, and the early effects of MSCs on neurogenic processes and gliosis at the lesion site. HI brain injury was induced in 9-day-old mice and MSCs were administered intranasally at 10days post-HI. The kinetics of MSC migration were investigated by immunofluorescence and MRI analysis. BDNF and NGF gene expression was determined by qPCR analysis following MSC co-culture with HI brain extract. Nestin, Doublecortin, NeuN, GFAP, Iba-1 and M1/M2 phenotypic expression was assessed over time. MRI and immunohistochemistry analyses showed that MSCs reach the lesion site already within 2h after intranasal administration. At 12h after administration the number of MSCs at the lesion site peaks and decreases significantly at 72h. The number of DCX(+) cells increased 1 to 3days after MSC administration in the SVZ. At the lesion, GFAP(+)/nestin(+) and DCX(+) expression increased 3 to 5days after MSC-treatment. The number of NeuN(+) cells increased within 5days, leading to a dramatic regeneration of the somatosensory cortex and hippocampus at 18days after intranasal MSC administration. Interestingly, MSCs expressed significantly more BDNF gene when exposed to HI brain extract in vitro. Furthermore, MSC-treatment resulted in the resolution of the glial scar surrounding the lesion, represented by a decrease in reactive astrocytes and microglia and polarization of microglia towards the M2 phenotype. In view of the current lack of therapeutic strategies, we propose that intranasal MSC administration is a powerful therapeutic option through its functional repair of the lesion represented by regeneration of the cortical and hippocampal structure and decrease of gliosis.

The effects of topical collagen treatment on wound breaking strength and scar cosmesis in rats

BACKGROUND

Topical application of collagen has been suggested to enhance wound healing; however, its long-term effect on wounds has not been studied in a rat model.

HYPOTHESIS

Topical application of collagen type I will not facilitate incision healing or cosmesis in rats up to 28 days postwounding.

METHODS

The effects of bovine collagen type I (6 mg/mL) on the rat surgical paired skin incision model were examined. Each rat served as its own control in which topical collagen was applied to one incision while normal saline (0.9%) was applied to the other incision. Rats were euthanized three (n=6), seven (n=6) and 28 (n=5) days after wounding. Tissue harvested from each time point was examined for maximal breaking strength, and for biochemical and histological analysis.

RESULTS

There were no statistically significant differences (ie, P<0.05) in maximum wound breaking strength between the collagen- and saline-treated wounds at all time points. Histological analysis revealed a similar infiltration of inflammatory cells and fibroblasts in the wound edges of all incisions when matched with time of wounding. Western blot analysis revealed no differences in fibronectin or collagen I content in all wounds in each rat.

CONCLUSIONS

The topical application of collagen did not facilitate wound healing from three to 28 days in the rat wound model.

AICAR-dependent AMPK activation improves scar formation in the aged heart in a murine model of reperfused myocardial infarction

We have demonstrated that scar formation after myocardial infarction (MI) is associated with an endogenous pool of CD44(pos)CD45(neg) multipotential mesenchymal stem cells (MSC). MSC differentiate into fibroblasts secreting collagen that forms a scar and mature into myofibroblasts that express alpha smooth muscle actin (α-SMA) that stabilizes the scar. In the aging mouse, cardiac repair after MI is associated with impaired differentiation of MSC; MSC derived from the aged hearts form dysfunctional fibroblasts that deposit less collagen in response to transforming growth factor beta-1 (TGF-β1) and poorly mature into myofibroblasts. We found in vitro that the defect in myofibroblast maturation can be remedied by AICAR, which activates non-canonical TGF-β signaling through AMP-activated protein kinase (AMPK). In the present study, we injected aged mice with AICAR and subjected them to 1h occlusion of the left anterior descending artery (LAD) and then reperfusion for up to 30days. AICAR-dependent AMPK signaling led to mobilization of an endogenous CD44(pos)CD45(neg) MSC and its differentiation towards fibroblasts and myofibroblasts in the infarct. This was accompanied by enhanced collagen deposition and collagen fiber maturation in the scar. The AICAR-treated group has demonstrated reduced adverse remodeling as indicated by improved apical end diastolic dimension but no changes in ejection fraction and cardiac output were observed. We concluded that these data indicate the novel, previously not described role of AMPK in the post-MI scar formation. These findings can potentially lead to a new therapeutic strategy for prevention of adverse remodeling in the aging heart.

Effect of hyaluronic acid-carboxymethylcellulose solution on perineural scar formation after sciatic nerve repair in rats

Background

Scar tissue formation is the major cause of failure in peripheral nerve surgery. Use of a hyaluronic acid-carboxymethylcellulose (HA-CMC) membrane (Seprafilm) as a solid anti-adhesion barrier agent is one of the therapeutic approaches to reduce postoperative scar tissue formation. However, a solid membrane may not be suitable for repair of a weak peripheral nerve site. This study examined the effect of HA-CMC solution on perineural scar formation after peripheral nerve repair in rats.

Methods

The sciatic nerves of 40 rats were transected and then immediately repaired using 10-0 nylon. The nerves were divided randomly into two groups. Saline and HA-CMC solution were applied topically to the nerve repair sites in the control and experimental groups, respectively. Reoperation was performed at 3, 6, 9, and 12 weeks to assess scar tissue formation. The assessment included the quality of wound healing, presence of perinueral adhesion, cellular components of the scar tissue, thickness of the scar tissue and histomorphological organization of the repair site.

Results

Topical application of the HA-CMC solution significantly decreased the macroscopic nerve adherence score and the numbers of the cellular components such as fibroblasts and inflammatory cells (p < 0.05, Mann-Whitney U-test). The scar tissue formation index was significantly lower in the experimental group at 12 weeks than that in the control group (p < 0.05, Mann-Whitney U-test). The grading scores of the histomorphological axonal organization at the repair site were significantly higher in the experimental group than those in the control group at 12 weeks (p < 0.05, Mann-Whitney U-test). No evidence of wound dehiscence or inflammatory reactions against the HA-CMC solution was noted.

Conclusions

Topical application of a HA-CMC solution is effective in reducing the perineural scar formation and adhesion after sciatic nerve repair in rats, and is effective in promoting peripheral nerve regeneration at the repair site.

Beyond the borders of keloid formation: A case report

The keloid scar is a cutaneous mass characterized by nodular fibroblastic proliferation of dermis and a predilection for distinctive anatomical locations. However, keloid extension to neighbouring tissue as a nonsyndromic entity has not been described. In the present report, a case involving a 48-year-old woman with extensive bilateral keloids of the ear lobules and neck following ear piercing is presented.