Influence of the anti‐inflammatory cytokine interleukin‐4 on human joint capsule myofibroblasts

Post‐traumatic joint contracture was reported to be associated with elevated numbers of contractile myofibroblasts (MFs) in the healing capsule. During the physiological healing process, the number of MFs declines; however, in fibroconnective disorders, MFs persist. The manifold interaction of the cytokines regulating the appearance and persistence of MFs in the pathogenesis of joint contracture remains to be elucidated. The objective of our current study was to analyze the impact of the anti‐inflammatory cytokine interleukin (IL)‐4 on functional behavior of MFs. Cells were isolated from human joint capsule specimens and challenged with three different concentrations of IL‐4 with or without its neutralizing antibody. MF viability, contractile properties, and the gene expression of both alpha‐smooth muscle actin (α‐SMA) and collagen type I were examined. Immunofluorescence staining revealed the presence of IL‐4 receptor (R)‐alpha (α) on the membrane of cultured MFs. The cytokine IL‐4 promoted MF viability and enhanced MF modulated contraction of collagen gels. Moreover, IL‐4 intervened in gene expression by up‐regulation of α‐SMA and collagen type I mRNA. These effects could be specifically lowered by the neutralizing IL‐4 antibody. On the basis of our findings we conclude that the anti‐inflammatory cytokine IL‐4 specifically regulates viability and the contractile properties of MFs via up‐regulating the gene expression of α‐SMA and collagen type I. IL‐4 may be a helpful target in developing anti‐fibrotic therapeutics for post‐traumatic joint contracture in human. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1290–1298, 2017.

     

Normal and keloid fibroblasts are differentially influenced by IFN‐γ and triamcinolone as well as by their combination

Impaired wound healing as well as imbalanced cell proliferation and extracellular matrix synthesis and degeneration can cause aberrant scarring. The most severe impacts of such scarring on patients' lives are stigmatization and physical restriction. Although, a broad variety of combinatorial approaches with, e.g., glucocorticoids, chemotherapeutics, and immunomodulators are used, there is still a high recurrence rate of keloids. The aim of this study was to investigate which influence interferon γ (IFN‐γ, 1.000–10.000 IU/mL) and/or triamcinolone acetonide (TA, 1 μg/mL) have on proliferation, cell viability, collagen type I synthesis, and cytokine secretion in healthy and keloid fibroblasts. It was shown that mono‐treatment with IFN‐γ or TA for 2 days induced a severe reduction of the proliferative potential in both cell species. The combinatory treatment (IFN‐γ plus TA) of keloid fibroblasts enhanced the anti‐proliferative effect of the mono‐treatments, whereas no additional anti‐proliferative effect was observed in normal fibroblasts. Furthermore, we observed that the combinatory treatment regimen reduced the expression of α‐smooth muscle actin (α‐SMA), an actin isotype contributing to cell‐generated mechanical tension, in keloid fibroblasts. In normal fibroblasts, α‐SMA was reduced by the mono‐treatment with IFN‐γ as well as by the combinatory treatment. The analysis of collagen‐type I synthesis revealed that TA did not reduce collagen type I synthesis in normal fibroblasts but in keloid fibroblasts. IFN‐γ reduced in both cell species the collagen type I synthesis. The combination of TA and IFN‐γ intensified the previously observed collagen type I synthesis reduction in keloid fibroblasts. The herein presented data suggest the combinatory application of IFN‐γ and TA as a promising therapy concept for keloids.     

Interferon‐gamma inhibits healing post scald burn injury

Impaired healing after severe burns remains a reason for prolonged hospitalization, opportunistic infections, and debilitating scarring. Interferon‐gamma (IFN‐γ) is an important immune regulator that has been shown to inhibit collagen synthesis by fibroblasts, resulting in delayed healing in incision wounds. To determine whether IFN‐γ plays similar roles in the healing process after severe burn, we induced scald injury in mice deficient or sufficient in IFN‐γ and examined local responses. In the absence of IFN‐γ, scalded areas healed faster. This was associated with attenuated local inflammatory responses, enhanced reepithelialization, increased proliferation of keratinocytes in reepithelialized leading edges, and up‐regulation of growth factors in burned skin areas. Furthermore, angiogenesis and myofibroblast formation commenced and terminated earlier in IFN‐γ^–/– mice compared with wild type (WT) controls. Our observations demonstrate that inhibition of IFN‐γ results in accelerated healing after burn injury by dampening excessive inflammation and facilitating reepithelialization, collagen deposition, and wound contraction.     

Simvastatin inhibits transforming growth factor‐β1‐induced expression of type I collagen,CTGF, and α‐SMA in keloid fibroblasts

Simvastatin, a 3‐hydroxy‐3‐methylglutaryl coenzyme‐A reductase inhibitor, is used to reduce cholesterol levels. Accumulating evidence has revealed the immunomodulatory and anti‐inflammatory effects of simvastatin that prevent cardiovascular diseases. In addition, the beneficial effects of statins on fibrosis of various organs have been reported. However, the functional effect of statins on dermal fibrosis of keloids has not yet been explored. The objective of this study was to determine whether simvastatin could affect dermal fibrosis associated with keloids. We examined the effect of simvastatin on transforming growth factor (TGF)‐β1‐induced production of type I collagen, connective tissue growth factor (CTGF or CCN2), and α‐smooth muscle actin (α‐SMA). Keloid fibroblasts were cultured and exposed to different concentrations of simvastatin in the presence of TGF‐β1, and the effects of simvastatin on TGF‐β1‐induced collagen and CTGF production in keloid fibroblasts were determined. The type I collagen, CTGF, and α‐SMA expression levels and the Smad2 and Smad3 phosphorylation levels were assessed by Western blotting. The effect of simvastatin on cell viability was evaluated by assessing the colorimetric conversion of 3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5‐diphenyltetrazolium bromide. Simvastatin suppressed TGF‐β1‐induced type I collagen, CTGF, and α‐SMA production in a concentration‐dependent manner. The TGF‐β1‐induced Smad2 and Smad3 phosphorylation levels were abrogated by simvastatin pretreatment. The inhibition of type I collagen, CTGF, and α‐SMA expression by simvastatin was reversed by geranylgeranyl pyrophosphate, suggesting that the simvastatin‐induced cellular responses were due to inhibition of small GTPase Rho involvement. A RhoA activation assay showed that preincubation with simvastatin significantly blocked TGF‐β1‐induced RhoA activation. The Rho‐associated coiled kinase inhibitor Y27632 abrogated TGF‐β1‐induced production of type I collagen, CTGF, and α‐SMA. However, Y27632 had no significant effect on TGF‐β1‐induced phosphorylation of Smad2 and Smad3. In conclusion, the present study suggests that simvastatin is an effective inhibitor of TGF‐β1‐induced type I collagen, CTGF, and α‐SMA production in keloid fibroblasts.     

Interferon‐γ plays a role in bone formation in vivo and rescues osteoporosis in ovariectomized mice

Interferon γ (IFN‐γ) is a cytokine produced locally in the bone microenvironment by cells of immune origin as well as mesenchymal stem cells. However, its role in normal bone remodeling is still poorly understood. In this study we first examined the consequences of IFN‐γ ablation in vivo in C57BL/6 mice expressing the IFN‐γ receptor knockout phenotype (IFNγR1^?/?). Compared with their wild‐type littermates (IFNγR1^+/+), IFNγR1^?/? mice exhibit a reduction in bone volume associated with significant changes in cortical and trabecular structural parameters characteristic of an osteoporotic phenotype. Bone histomorphometry of IFNγR1^?/? mice showed a low‐bone‐turnover pattern with a decrease in bone formation, a significant reduction in osteoblast and osteoclast numbers, and a reduction in circulating levels of bone‐formation and bone‐resorption markers. Furthermore, administration of IFN‐γ (2000 and 10,000 units) to wild‐type C57BL/6 sham‐operated (SHAM) and ovariectomized (OVX) female mice significantly improved bone mass and microarchitecture, mechanical properties of bone, and the ratio between bone formation and bone resorption in SHAM mice and rescued osteoporosis in OVX mice. These data therefore support an important physiologic role for IFN‐γ signaling as a potential new anabolic therapeutic target for osteoporosis. © 2011 American Society for Bone and Mineral Research.     

Potential molecular mechanisms of negative pressure in promoting wound healing

Negative pressure wound therapy (NPWT) has been widely used in various lesions. This study aimed to explore the biological effects of negative pressure on the polymorphonuclear neutrophils (PMNs), macrophages, and epidermal keratinocyte cells involved in wound healing. PMNs differentiated from HL‐60, macrophages were derived from THP‐1 monocytes, and keratinocytes were cultured in vitro, and they were treated with 0, ?0.03 mp, and ?0.05 mp, respectively. Cell ultrastructure; viability; apoptosis; and protein factors such as tumour necrosis factor‐α (TNF‐α), interferon‐γ (IFN‐γ), epidermal growth factor (EGF), epidermal growth factor receptor (EGFR), interleukin‐17 (IL‐17), and cell division cycle 42 (Cdc42) were determined by transmission electron microscopy (TEM), CCK8, flow cytometry (FCM), ELISA, and simple Western assays, respectively. After negative pressure stimulation, the cell ultrastructure of PMNs and macrophages cells was presented with a marked increase of lysosomes and a relative decrease of mitochondria. In addition, the cell viability was enhanced in PMNs and macrophages in a pressure‐dependent manner and apoptosis ratios were significantly reduced in PMNs and macrophages. In addition, under ?0.05 negative pressure, IFN‐γ and IL‐17 were significantly increased in PMNs or macrophages. Moreover, increased EGF and EGFR and Cdc42 levels in keratinocytes induced by the ?0.05 mpa were detected, indicating that the migration chemotaxis of keratinocyte cells was enhanced. Negative pressure might promote cell proliferation, accelerate inflammatory responses, and promote epithelialisation during wound healing by increasing IFN‐γ, IL‐17, Cdc42, EGF, and EGFR in PMNs, macrophages, or keratinocytes under different negative pressures.     

Rosiglitazone modulates the behaviors of diabetic host‐derived fibroblasts in a carboxymethyllysine‐modified collagen model

Utilizing a three‐dimensional in vitro glycated collagen model, we evaluated the therapeutic effects of a peroxisome proliferator‐activated receptor‐γ ligand, rosiglitazone, and its potential as a topical treatment of diabetic chronic wounds. Rosiglitazone induced fibroblast migration, α‐smooth muscle actin production, and transformation into myofibroblasts in the presence of advanced glycation end products. Both transforming growth factor β and peroxisome proliferator‐activated receptor‐γ expression were induced, while the receptor for advanced glycation end products was suppressed. Lastly, the reduced activities of matrix metalloproteinase‐2 and matrix metalloproteinases‐9 in the carboxymethyllysine‐modified collagen matrices by rosiglitazone increases extracellular matrix deposition. Our findings identify rosiglitazone as a candidate for localized topical treatment of diabetic chronic wounds.     

Exogenous Interferon‐γ Immunotherapy for Invasive Fungal Infections in Kidney Transplant Patients

The incidence of invasive fungal infections (IFIs) in nonneutropenic solid organ transplant patients is increasing. We report our clinical experience with the use of interferon‐γ (IFN‐γ) immunotherapy in seven renal transplant patients who developed life threatening, disseminated IFIs refractory to conventional antifungal drug therapy. The infections were all microbiologically and histologically proven. The rapid cure of these disseminated infections with exogenous IFN‐γ injections was not associated with impaired kidney allograft function despite the use of liposomal amphotericin B in all cases. No clinical toxicity from the IFN‐γ immunotherapy was seen and no IFI relapsed during long‐term follow‐up. Our experience is both uncontrolled and in patients with unpredictable fungal infection‐related outcomes. However, compared to standard approaches, the accelerated cure of life threatening, disseminated IFIs with 6 weeks of combination antifungal drug therapy and IFN‐γ immunotherapy saved lives, retained allograft function and led to substantial cost savings in this small patient group.     

Erythropoietin and its non‐erythropoietic derivative: Do they ameliorate renal tubulointerstitial injury in ureteral obstruction?

Objectives: Pleiotropic effects of recombinant human erythropoietin (EPO) have recently been discovered in many non‐renal animal models. The renoprotective effects of EPO and carbamylated‐erythropoietin (CEPO), a novel EPO which has a small stimulatory effect on hemoglobin, have never been explored in unilateral ureteral obstruction (UUO), a chronic tubulointerstitial (TI) disease model which is independent of systemic factors. Methods: In order to examine the effects of EPO and CEPO treatments on renal TI injury, 36 male Sprague‐Dawley rats, weighing 250–320 g, underwent: UUO without treatment (group 1, n = 12), UUO with EPO (groups 2, n = 12), and UUO with CEPO (group 3, n = 12). EPO and CEPO were injected subcutaneously at a dose of 5000 u/kg to each respective rat at 1 day pre‐UUO and at day 3, 7 and 10 post‐UUO. After days 3, 7, and 14 of UUO, TI injury, collagen, α‐smooth muscle actin (α‐SMA) positive cell, ED1‐positive cell, terminal deoxynucleotidyl transferase (TdT) mediated nick‐end labeling (TUNEL)‐positive cell, and transforming growth factor‐β1 (TGF‐β1) messenger ribonucleic acid (mRNA) were determined. Bcl‐2 expression was also assessed to verify the mechanism of apoptosis. Results: At day 14 UUO caused severe TI injury with a significant increase in collagen, α‐SMA, ED1‐positive cell, TUNEL‐positive cell, and TGF‐β1 mRNA expression. Administration of EPO and CEPO significantly attenuated TI injury, collagen, ED1‐positive cells, and TUNEL‐positive cells. Only CEPO‐treated rats had decreased α‐SMA positive cells and TGF‐β1 mRNA. The expression of Bcl‐2 was demonstrated only in EPO‐treated rats. The hematocrit levels in EPO‐treated rats were higher than the control and CEPO‐treated rats. Conclusions: EPO and CEPO can limit 14‐day UUO‐induced TI injury by reducing inflammation, interstitial fibrosis, and tubular apoptosis.     

Cell line IDG‐SW3 replicates osteoblast‐to‐late‐osteocyte differentiation in vitro and accelerates bone formation in vivo

Osteocytes are the most abundant cells in bone yet are the most challenging to study because they are embedded in a mineralized matrix. We generated a clonal cell line called IDG‐SW3 (for Immortomouse/Dmp1‐GFP‐SW3) from long‐bone chips from mice carrying a Dmp1 promoter driving GFP crossed with the Immortomouse, which expresses a thermolabile SV40 large T antigen regulated by interferon γ (IFN‐γ). Cells from these mice can be expanded at 33 °C in the presence of IFN‐γ and then allowed to resume their original phenotype at 37 °C in the absence of IFN‐γ. IDG‐SW3 cells are Dmp1‐GFP^? and T antigen⁺ under immortalizing conditions but Dmp1‐GFP⁺ and T antigen^? under osteogenic conditions. Like osteoblasts, they express alkaline phosphatase and produce and mineralize a type 1 collagen matrix containing calcospherulites. Like early osteocytes, they express E11/gp38, Dmp1, MEPE, and Phex. Like late osteocytes, they develop a dendritic morphology and express SOST/sclerostin and fibroblast growth factor 23 (FGF‐23), regulated by parathyroid hormone (PTH) and 1,25‐dihydroxyvitamin D₃. When cultured on 3D matrices, they express Dmp1‐GFP and sclerostin. When the 3D cultures are implanted in calvarial defects in vivo, they accelerate bone healing. This cell line should prove useful for studying osteoblast‐to‐osteocyte transition, mechanisms for biomineralization, osteocyte function, and regulation of SOST/sclerostin and FGF‐23. © 2011 American Society for Bone and Mineral Research     

Auxiliary proteins that facilitate formation of collagen‐rich deposits in the posterior knee capsule in a rabbit‐based joint contracture model

Post‐traumatic joint contracture is a debilitating consequence of trauma or surgical procedures. It is associated with fibrosis that develops regardless of the nature of initial trauma and results from complex biological processes associated with inflammation and cell activation. These processes accelerate production of structural elements of the extracellular matrix, particularly collagen fibrils. Although the increased production of collagenous proteins has been demonstrated in tissues of contracted joints, researchers have not yet determined the complex protein machinery needed for the biosynthesis of collagen molecules and for their assembly into fibrils. Consequently, the purpose of our study was to investigate key enzymes and protein chaperones needed to produce collagen‐rich deposits. Using a rabbit model of joint contracture, our biochemical and histological assays indicated changes in the expression patterns of heat shock protein 47 and the α‐subunit of prolyl 4‐hydroxylase, key proteins in processing nascent collagen chains. Moreover, our study shows that the abnormal organization of collagen fibrils in the posterior capsules of injured knees, rather than excessive formation of fibril‐stabilizing cross‐links, may be a key reason for observed changes in the mechanical characteristics of injured joints. This result sheds new light on pathomechanisms of joint contraction, and identifies potentially attractive anti‐fibrotic targets. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:489–501, 2016.     

Role of IL‐17 and TGF‐β in peritoneal adhesion formation after surgical trauma

Peritoneal adhesions are fibrous tissues formed after surgery. Both cytokines and transforming growth factors (TGFs) are involved in this process. The objective of this study was to investigate the cross talk between these entities. Peritoneal drainage fluid after surgery from patients and rodent models was examined by enzyme‐linked immunosorbent assay and fluorescence‐activated cell sorter. Data showed that the concentrations of interferon (IFN)‐γ and interleukin (IL)‐17 reached their peaks 6–12 hours after surgery, whereas TGF‐β1 concentrations showed two postoperative peak time points at 2 and 72–96 hours. By neutralizing IFN‐γ, IL‐17 6–12 hours, and TGF‐β1 72–96 hours after surgery, the degree of adhesion reduced significantly. However, neutralizing TGF‐β1 2 hours after surgery did not affect adhesion formation. Furthermore, in vitro studies showed that compared with the fibroblasts that were directly stimulated with TGF‐β1, the prestimulation of IL‐17 promoted plasminogen activator inhibitor‐1 production while inhibiting tissue‐type plasminogen activator production. Moreover, additional stimulation with IFN‐γ enhanced this effect. Together, these data indicate that IL‐17 may promote adhesion formation by increasing the reaction of fibroblasts against TGF‐β1. Blocking IL‐17 might have a therapeutic potential in preventing adhesion formation after surgery.     

Down‐regulation of mir‐27b promotes angiogenesis and fibroblast activation through activating PI3K/AKT signaling pathway

To study the effects of mir‐27b on angiogenesis and fibroblast activation and to explore its further mechanism. Humanmicrovascular endothelial cell (HMEC)‐1 and humannormal skin fibroblast (BJ) cells were treated with mir‐27b inhibitor negative control reagent, mir‐27b inhibitor, LY294002, and mir‐27b inhibitor + LY294002, respectively. 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) was used to detect the T‐cell proliferation. The migration ability was detected by Scratch assays. The angiogenesis of HMEC‐1 cells was observed by in vitro tube formation assay. The mRNA and protein expression of vascular endothelial growth factor (VEGF) in HMEC‐1 cells and the mRNA and protein expression of collagen I, collagen III, α‐SMA, and MMP1 in BJ cells were detected by quantitativereal‐time polymerase chain reaction (qRT‐PCR) and Western blot, respectively. Meanwhile, the PI3K/protein kinase B (AKT) pathway‐related proteins were also detected by Western blot. The proliferation, migration, angiogenesis, the mRNA and protein expression of VEGF and the protein expression of p‐PI3K and p‐AKT in HMEC‐1 cells were increased after treated with mir‐27b inhibitor. Meanwhile, the proliferation, migration, and the protein expression of collagen I, collagen III, α‐SMA, MMP1, p‐PI3K, and p‐AKT in BJ cells were increased after treated with mir‐27b inhibitor. However, the angiogenesis and fibroblast activation of mir‐27b inhibitor was reversed by LY294002, and the activate effect to PI3K/AKT pathway was also inhibited. Down‐regulation of mir‐27b could promote angiogenesis and fibroblast activation, and its mechanism is related to activate PI3K/AKT signaling pathway.     

Renal Allograft Recipients Fail to Increase Interferon‐γ During Invasive Fungal Diseases

Invasive fungal diseases are a major cause of death in renal allograft recipients. We previously reported that adjunctive recombinant human interferon‐γ therapy has clinical utility for invasive fungal diseases after renal transplantation. We have now developed a rapid peripheral blood‐based quantitative real‐time PCR assay that enables accurate profiling of cytokine imbalances. Our preliminary studies in renal transplant patients with invasive fungal diseases suggest that they fail to mount an adequate interferon‐γ response to the fungal infection. In addition, they have reduced IL‐10 and increased TNF‐α when compared to stable renal transplant patients. These preliminary cytokine profiling‐based observations provide a possible explanation for the therapeutic benefit of adjunctive human interferon‐γ therapy in renal allograft recipients with invasive fungal diseases.     

The effect of TGFβRI inhibition on fibroblast heterogeneity in hypertrophic scar 2D in vitro models

In burn patients, wound healing is often accompanied by hypertrophic scarring (HTS), resulting in both functional and aesthetic problems. HTSs are characterized by abundant presence of myofibroblasts (MFs) residing in the dermis. HTS development and MF persistence is primarily regulated by TGF-β signalling. A promising method to target the transforming growth factor receptor I (TGFβRI; also known as activin-like kinase 5 (ALK5)) is by making use of exon skipping through antisense oligonucleotides. In HTS the distinguishing border between the papillary dermis and the reticular dermis is completely abrogated, thus exhibiting a one layered dermis containing a heterogenous fibroblast population, consisting of papillary fibroblasts (PFs), reticular fibroblasts (RFs) and MFs. It has been proposed that PFs, as opposed to RFs, exhibit anti-fibrotic properties. Currently, it is still unclear which fibroblast subtype is most affected by exon skipping treatment.Therefore, the aim of this study was to investigate the effect of TGFβRI inhibition by exon skipping in PF, RF and HTS fibroblast monocultures.Morphological analyses revealed the presence of a PF-like population after exon skipping in the different fibroblast cultures. This observation was further confirmed by the expression of genes specific for PFs, demonstrated by qPCR analyses. Further investigations on mRNA and protein level revealed that indeed MFs and to a lesser extent RFs are targeted by exon skipping. Furthermore, collagen gel contraction analysis showed that ALK5 exon skipping reduced TGF-β- induced contraction together with decreased alpha-smooth muscle actin expression levels.In conclusion, we show for the first time that exon skipping primarily targets pro-fibrotic fibroblasts. This could be a promising step towards reduced HTS development of burn tissue.     

Seasonal immunohistochemical reactivity of S‐100 and α‐smooth muscle actin proteins in the epididymis of dromedary camel,Camelus dromedarius

The S‐100 and alpha smooth muscle actin (α‐SMA) proteins have been localised in epididymal tissue of several mammalian species, but there have been no data for a seasonal work in camel. The aim of this study was to investigate the immunoreactivities of S‐100 and α‐SMA proteins in the epididymis of dromedary camel during breeding and nonbreeding seasons. The immunopositive signals for both proteins were observed in different regions of camel epididymis. S‐100‐immunopositive signals were noted in both the epididymal epithelium and the intertubular connective tissue, while α‐SMA signals were confined to the intertubular connective tissue, especially in the peritubular smooth muscle coat and the blood vessels. This study showed an increase in the intensity of S‐100 and α‐SMA immunoreactions during the breeding season in different regions of camel epididymis than that seen in the nonbreeding season. In conclusion, epididymis might be considered as a source of S‐100 and α‐SMA proteins in the camel and the secretion of these proteins showed distinct seasonal variations. Further, S‐100 and α‐SMA may affect the structural and physiological states of the epididymal duct.     

Modulation of wound contracture α‐smooth muscle actin and multispecific vitronectin receptor integrin αvβ3 in the rabbit's experimental model

The myofibroblast, a major component of granulation tissue, is a key cell during wound healing, tissue repair and connective tissue remodelling. Persistence of myofibroblasts within a fibrotic lesion leads to excessive scarring impairing function and aesthetics. Various wound‐healing cytokines can be modulated by topical application of active agents to promote optimal wound healing and improve scar quality. Thus, the myofibroblast may represent an important target for wound‐healing modulation to improve the evolution of conditions such as hypertrophic scars. The purpose of this work is to study the modulation of myofibroblasts and integrin αvβ3 in a full thickness wound performed on rabbits treated with different topical agents using: (1) saline, (2) Tegaderm occlusive dressing (3) silver sulfadiazine and (4) moist exposed burn ointment (MEBO). The reepithelialisation was 4 days faster in the MEBO group compared with the other therapies with less oedema formation, delayed contraction, less inflammatory cells and the lowest transepidermal water loss (TEWL) resulting in a soft scar. Although α‐smooth muscle actin (α‐SMA) was the highest around day 12 in the MEBO group, wound contraction and myofibroblast's activity were the least for the same period probably because of a downregulation of the integrin αvβ3. It seems that the effect of MEBO could be more pronounced on force transmission rather then on force generation. Greater insight into the pathology of scars may translate into non surgical treatments in the future and further work in myofibroblast biology will eventually result in efficient pharmacological tools, improving the evolution of healing and scar formation.     

Curcumin accelerates cutaneous wound healing via multiple biological actions: The involvement of TNF‐α, MMP‐9, α‐SMA,and collagen

Curcumin, a constituent of the turmeric plant, has antitumor, anti‐inflammatory, and antioxidative effects, but its effects on wound healing are unclear. We created back wounds in 72 mice and treated them with or without topical curcumin (0.2 mg/mL) in Pluronic F127 gel (20%) daily for 3, 5, 7, 9, and 12 days. Healing in wounds was evaluated from gross appearance, microscopically by haematoxylin and eosin staining, by immunohistochemistry for tumour necrosis factor alpha and alpha smooth muscle actin, and by polymerase chain reaction amplification of mRNA expression levels. Treatment caused fast wound closure with well‐formed granulation tissue dominated by collagen deposition and regenerating epithelium. Curcumin increased the levels of tumour necrosis factor alpha mRNA and protein in the early phase of healing, which then decreased significantly. However, these levels remained high in controls. Levels of collagen were significantly higher in curcumin‐treated wounds. Immunohistochemical staining for alpha smooth muscle actin was increased in curcumin‐treated mice on days 7 and 12. Curcumin treatment significantly suppressed matrix metallopeptidase‐9 and stimulated alpha smooth muscle levels in tumour necrosis factor alpha‐treated fibroblasts via nuclear factor kappa B signalling. Thus, topical curcumin accelerated wound healing in mice by regulating the levels of various cytokines.     

ß2-adrenergic receptor activation delays dermal fibroblast-mediated contraction of collagen gels via a cAMP-dependent mechanism

Dermal fibroblasts actively contribute to wound healing by migrating to the wound, synthesizing extracellular matrices, and generating mechanical forces within the wound to initiate wound contraction. Fibroblast-seeded collagen gels provide an in vitro model to study wound contraction. The authors are evaluating the role of the adrenergic signaling system in cutaneous wound repair and recently found that beta2-adrenergic receptor (beta2-AR) activation markedly decreases keratinocyte migration, an essential step in wound reepithelialization. Because the beta2-ARs are also expressed on dermal fibroblasts, a study was initiated to determine the effects of beta-adrenergic agonists on dermal fibroblast-mediated collagen gel contraction. A beta-agonist (isoproterenol) delayed gel contraction in a dose-dependent manner. A beta2-AR specific antagonist (ICI 118,551) prevented the delay, indicating that the beta2-AR alone mediated the delay. The active cyclic adenosine monophosphate (cAMP) analog also delayed collagen gel contraction, whereas an inactive cAMP analog partially prevented the delay, suggesting that the mechanism for beta-AR agonist-mediated delay was partly cAMP-dependent. Identifying and characterizing agents that modulate wound contraction improves understanding of the wound healing process and could result in novel therapeutic strategies for preventing unwanted wound contraction in burn and trauma patients.