Role of elevated plasma transforming growth factor-beta1 levels in wound healing

miR-758-3p/ILK signaling modulated angiogenesis by regulating VEGFA in wound healing

Chronic wounds cause physical, psychological and economic damage to patients, while therapeutic choices are limited. ILK was reported to play key roles in both fibrosis and angiogenesis, which are two important factors during wound healing. However, the function of ILK during vascularization in wounds remains unclear. In our study, we found increased ILK expression in chronic wound tissues compared to adjacent tissue, as well as a positive relationship between ILK expression and microvessel density. Moreover, fibroblasts overexpressing ILK showed an enhanced ability to promote HUVEC migration and tube formation, during which PI3K/Akt, downstream of ILK, played key roles and VEGFA was the key cytokine. Considering the important function of ILK in wound healing and the lack of an ILK activator, we investigated microRNAs targeting ILK and found that miR-758-3p could target ILK to regulate its transcription. The inhibition of miR-758-3p increased ILK expression and sequentially upregulated VEGFA and activated angiogenesis in vivo and in vitro. Taken together, these results revealed that ILK played a key role in wound healing by regulating angiogenesis and that activating ILK by inhibiting miR-758-3p was an effective way to promote wound healing. Whether miR-758-3p/ILK signaling can be utilized as a therapeutic target for wound healing requires further investigation.

In Vitro, Ex Vivo, and In Vivo Approaches for Investigation of Skin Scarring: Human and Animal Models

Significance: The cutaneous repair process naturally results in different types of scarring that are classified as normal or pathological. Affected individuals are often affected from an esthetic, physical (functional), and psychosocial perspective. The distinct nature of scarring in humans, particularly the formation of pathological scars, makes the study of skin scarring a challenge for researchers in this area. Several established experimental models exist for studying scar formation. However, the increasing development and validation of newly emerging models have made it possible to carry out studies focused on different variables that influence this unique process. Recent Advances: Experimental models such as in vitro, ex vivo, and in vivo models have obtained different degrees of success in the reproduction of the scar formation in its native milieu and true environment. These models also differ in their ability to elucidate the molecular, cellular, and structural mechanisms involved in scarring, as well as for testing new agents and approaches for therapies. The models reviewed here, including cells derived from human skin and in vivo animal models, have contributed to the advancement of skin scarring research. Critical Issues and Future Directions: The absence of experimental models that faithfully reproduce the typical characteristics of the different types of human skin scars makes the improvement of validated models and the establishment of new ones a critical unmet need. The fields of wound healing research combined with tissue engineering have offered newer alternatives for experimental studies with the potential to provide clinically useful knowledge about scar formation.

Functionalized Electrospun Double-Layer Nanofibrous Scaffold for Wound Healing and Scar Inhibition

Considerable advances have been made in developing materials that promote wound healing and inhibit scar formation in clinical settings. However, some challenges, such as cumbersome treatment processes and determination of optimal treatment time, remain unresolved. Thus, developing a multifunctional wound dressing with both wound healing and scar inhibition properties is crucial. Here, we present an integrated electrospun fibrous composite membrane (MPC12) for wound healing and scar inhibition, consisting of a quaternized chitosan-loaded inner membrane (PCQC5) and quaternized silicone-loaded outer membrane (MQP12). The inner membrane effectively coagulates blood and promotes wound healing, and the outer membrane moisturizes, resists bacteria, and inhibits scar formation. In vivo evaluation in a rabbit ear model revealed that MPC12 treatment results in faster wound healing and better alleviation of scar hypertrophy than treatment with commercial products (KELO-COTE and MSSG). Our strategy offers an excellent solution for the potential integration of wound healing and scar inhibition.

The Role of Cell Division Autoantigen 1 (CDA1) in Renal Fibrosis of Diabetic Nephropathy

The common kidney disease diabetic nephropathy (DN) accounts for significant morbidity and mortality in patients with diabetes, and its effective diagnosis in incipient stages is still lacking. Renal fibrosis is the main pathological feature of DN. Cell division autoantigen 1 (CDA1), a phosphorylated protein encoded by TSPYL2 on the X chromosome, plays a fibrogenic role by modulating the transforming growth factor-β (TGF-β) signaling, but the exact mechanism remains unclear. TGF-β signaling has been recognized as the key factor in promoting the development and progression of DN. At present, strict control of blood sugar and blood pressure can significantly lower the development and progression of DN in the early stages, and many studies have shown that blocking TGF-β signaling can delay the progress of DN. However, TGF-β is a multifunctional cytokine. Its direct intervention may result in increased side effects. Therefore, the targeted intervention of CDA1 not only can block the TGF-β signaling pathway but also can reduce these side effects. In this article, we review the main physiological roles of CDA1, with particular attention to its effect and potential mechanism in the renal fibrosis of DN.

Comparison of the Effectiveness of Onion Extract, Topical Steroid, and Petrolatum Emollient in Cosmetic Appearance of Upper Blepharoplasty Scar

Purpose

To compare the effectiveness of onion extract, topical steroid, and petrolatum emollient in the prevention of scars in cases who underwent bilateral upper eyelid blepharoplasty.

Methods

A prospective, interventional, comparative, double-blinded case series was designed on cases who underwent upper lid blepharoplasty. After suture removal (1 week following the surgery), the eyelids of participants were randomly allocated into the three groups: The first group used onion extract on the right eyelids (n = 18), and the second group used topical steroid on the right eyelids (n = 19). In the third group, the control group, petrolatum emollient was used on the left eyelids (n = 37) of the first and second group's cases. They used drugs for 2 months and were evaluated by the Manchester Scar Scale (MSS) objectively by two graders who were blinded to the type of medication. MSS evaluates five different characteristics of the scar in addition to the Visual Analog Scale (VAS). These characteristics include color, distortion, contour, texture, and transparency. VAS scores the overall scar appearance which ranged among 0-10. The sum of the scores for the five different parameters, and VAS was calculated, analyzed, and compared among the groups.

Results

A total of 37 cases (74 eyelids) who underwent bilateral upper blepharoplasty were included. The mean ± standard deviation (SD) of age was 51.94 ± 9.26 years, 49.40 ± 9.37 years, and 47.00 ± 9.06 years in the onion extract, topical steroid, and petrolatum emollient groups, respectively (P = 0.275). There were no statistically significant differences in the mean ± SD of the sum of the MSS scores among the three groups (P = 0.924) or between the onion extract and topical steroid groups (P = 0.951). Furthermore, the color, distortion, contour, texture, transparency, and VAS scores were not statistically significantly different among the three groups or between the onion extract and topical steroid groups (P > 0.05).

Conclusion

There were no significant differences among these three groups of drugs regarding the appearance of the upper blepharoplasty scar.

Mitigation of Postsurgical Scars Using Lasers: A Review

Background:

Most postsurgical scars are considered esthetically and functionally acceptable. Currently, there is no definite consensus treatment for postsurgical scarring. The purpose of this review is to shed some light on the value of scar mitigation and the efficacy of different lasers employed on postsurgical wounds.

Methods:

A systematic literature review and computational analysis were conducted to identify relevant clinical articles that pertained to the use of lasers for mitigating postsurgical scars. Articles included the National Institutes of Health–National Center for Biotechnology Information–PubMed search and sources cited from relevant studies after 1995. Trials that attributed pre- and posttreatment scores of scar severity based on a verified scar evaluation scale (eg, Patient and Observer Scar Assessment Scale, Vancouver Scar Scale, Global Assessment Scale) were chosen. Clinical assessments varied for each study. To adequately assess the efficacy of the modalities, the final scaled scar appearance scores were realigned and normalized to a standard scale for unbiased comparison.

Results:

After filtering through a total of 124 studies, 14 relevant studies were isolated and thus included in the review. Studied lasers were as follows: Pulsed dye laser (PDL), carbon dioxide, diode, potassium titanyl phosphate (KTP), and erbium glass (Er-Glass) lasers.

Conclusion:

Treatment with lasers in the postsurgical wound healing phase is safe, effective, and advised in mitigation of pathologic scar formation.

Skin Wound Healing Effects and Action Mechanism of Acai Berry Water Extracts

The purpose of this study was to investigate the wound healing effect of acai berry water extracts (ABWE) and a possible underlying mechanism involved in its action using various in vitro and in vivo models. The wound healing effect of ABWE was evaluated by migration assay using HS68 fibroblast cells. In addition, its effect on mRNA expression of procollagen, fibronectin, and MMP-1 was determined. Moreover, the wound healing effect of ABWE was evaluated in in vivo wound models through macroscopic and microscopic observation. In addition, mRNA expression levels of wound related genes were determined. Results revealed that ABWE was not cytotoxic. It increased migration of HS68 fibroblast cells. ABWE increased mRNA expression levels of fibronectin but decreased the mRNA expression levels of MMP-1. ABWE also showed significantly potent wound healing effect in vivo based on macroscopic and histopathological observation and mRNA expression evaluation for wound related genes. Taken together, our results indicated that ABWE might have potential as a wound healing agent.

Keloids and Hypertrophic Scars: Pathophysiology, Classification, and Treatment

BACKGROUND

Keloid and hypertrophic scars represent an aberrant response to the wound healing process. These scars are characterized by dysregulated growth with excessive collagen formation, and can be cosmetically and functionally disruptive to patients.

OBJECTIVE

Objectives are to describe the pathophysiology of keloid and hypertrophic scar, and to compare differences with the normal wound healing process. The classification of keloids and hypertrophic scars are then discussed. Finally, various treatment options including prevention, conventional therapies, surgical therapies, and adjuvant therapies are described in detail.

MATERIALS AND METHODS

Literature review was performed identifying relevant publications pertaining to the pathophysiology, classification, and treatment of keloid and hypertrophic scars.

RESULTS

Though the pathophysiology of keloid and hypertrophic scars is not completely known, various cytokines have been implicated, including interleukin (IL)-6, IL-8, and IL-10, as well as various growth factors including transforming growth factor-beta and platelet-derived growth factor. Numerous treatments have been studied for keloid and hypertrophic scars,which include conventional therapies such as occlusive dressings, compression therapy, and steroids; surgical therapies such as excision and cryosurgery; and adjuvant and emerging therapies including radiation therapy, interferon, 5-fluorouracil, imiquimod, tacrolimus, sirolimus, bleomycin, doxorubicin, transforming growth factor-beta, epidermal growth factor, verapamil, retinoic acid, tamoxifen, botulinum toxin A, onion extract, silicone-based camouflage, hydrogel scaffold, and skin tension offloading device.

CONCLUSION

Keloid and hypertrophic scars remain a challenging condition, with potential cosmetic and functional consequences to patients. Several therapies exist which function through different mechanisms. Better understanding into the pathogenesis will allow for development of newer and more targeted therapies in the future.

Myofibroblasts in Palatal Wound Healing: Prospects for the Reduction of Wound Contraction after Cleft Palate Repair

The surgical closure of orofacial clefts is considered to impair maxillary growth and dento-alveolar development. Wound contraction and subsequent scar tissue formation, during healing of these surgical wounds, contribute largely to these growth disturbances. The potential to minimize wound contraction and subsequent scarring by clinical interventions depends on the surgeon’s knowledge of the events responsible for these phenomena. Fibroblasts initiate wound contraction, but proto-myofibroblasts and mature myofibroblasts are by far the most important cells in this process. Myofibroblasts are characterized by their cytoskeleton, which contains alpha-smooth-muscle actin. Additionally, their contractile apparatus contains bundles of actin microfilaments and associated contractile proteins, such as non-muscle myosin. This contractile apparatus is thought to be the major force-generating element involved in wound contraction. After closure of the wound, the myofibroblasts disappear by apoptosis, and a less cellular scar is formed. A reduction of contraction and scarring might be obtained by inhibition of myofibroblast differentiation, stimulation of their de-differentiation, stimulation of myofibroblast apoptosis, or impairment of myofibroblast function. In this review, we will discuss all of these possibilities, which ultimately may lead to a better outcome of cleft palate surgery.

ILK-PI3K/AKT pathway participates in cutaneous wound contraction by regulating fibroblast migration and differentiation to myofibroblast

The interactions between fibroblasts and the extracellular matrix in wound contraction are mainly mediated via integrin signaling. Integrin-linked kinase (ILK) is a key mediator in integrin signal transduction. We investigated the role of ILK in cutaneous wound contraction. We found that ILK was involved in cutaneous wound healing in rats, and ILK and PI3K/AKT inhibitors inhibited wound contraction and re-epithelialization, consequently delaying wound healing in vivo. Further, using in vitro studies, we demonstrated that ILK and PI3K/AKT inhibitors suppressed the contraction of fibroblast-populated collagen lattices, inhibited fibroblast migration, and interrupted the effect of TGF-β1 on promoting alpha smooth muscle actin (α-SMA) expression in fibroblasts. When ILK expression was directly blocked by ILK small interfering RNA transfection, the migration and α-SMA expression of normal dermal fibroblasts were significantly suppressed as well. The data suggest that the ILK-PI3K/AKT signaling pathway mediates cutaneous wound contraction by regulating fibroblast migration and differentiation to myofibroblasts.

The Use of Biologic Scaffolds in the Treatment of Chronic Nonhealing Wounds

Significance: Injuries to the skin as a result of illness or injury, particularly chronic nonhealing wounds, present a major healthcare problem. Traditional wound care approaches attempt to control the underlying causes, such as infection and ischemia, while the application of wound dressings aims to modify a poorly healing wound environment into a microenvironment more closely resembling an acute wound allowing the body to heal the wound naturally. Recent Advances: Regenerative medicine approaches, such as the use of biologic scaffold materials comprising an intact extracellular matrix (ECM) or individual components of the ECM, are providing new therapeutic options that focus upon the provision of biochemical cues that alter the wound microenvironment to facilitate rapid restoration of normal skin architecture. Critical Issues: The incidence of chronic nonhealing wounds continues to increase. For example, between 15% and 20% of diabetics are likely to develop chronic, nonhealing foot wounds creating an increasing burden on healthcare systems worldwide. Future Directions: Developing a thorough understanding of wound microenvironment and the mechanisms by which biologic scaffolds work in vivo has the potential to markedly improve outcomes in the clinical translation for the treatment of chronic wounds.

Cell factory-derived bioactive molecules with polymeric cryogel scaffold enhance the repair of subchondral cartilage defect in rabbits

We have explored the potential of cell factory-derived bioactive molecules, isolated from conditioned media of primary goat chondrocytes, for the repair of subchondral cartilage defects. Enzyme-linked immunosorbent assay (ELISA) confirms the presence of transforming growth factor-β1 in an isolated protein fraction (12.56 ± 1.15 ng/mg protein fraction). These bioactive molecules were used alone or with chitosan-agarose-gelatin cryogel scaffolds, with and without chondrocytes, to check whether combined approaches further enhance cartilage repair. To evaluate this, an in vivo study was conducted on New Zealand rabbits in which a subchondral defect (4.5 mm wide × 4.5 mm deep) was surgically created. Starting after the operation, bioactive molecules were injected at the defect site at regular intervals of 14 days. Histopathological analysis showed that rabbits treated with bioactive molecules alone had cartilage regeneration after 4 weeks. However, rabbits treated with bioactive molecules along with scaffolds, with or without cells, showed cartilage formation after 3 weeks; 6 weeks after surgery, the cartilage regenerated in rabbits treated with either bioactive molecules alone or in combinations showed morphological similarities to native cartilage. No systemic cytotoxicity or inflammatory response was induced by any of the treatments. Further, ELISA was done to determine systemic toxicity, which showed no difference in concentration of tumour necrosis factor-α in blood serum, before or after surgery. In conclusion, intra-articular injection with bioactive molecules alone may be used for the repair of subchondral cartilage defects, and bioactive molecules along with chondrocyte-seeded scaffolds further enhance the repair. Copyright © 2015 John Wiley & Sons, Ltd.

High-power femtosecond-terahertz pulse induces a wound response in mouse skin

Terahertz (THz) technology has emerged for biomedical applications such as scanning, molecular spectroscopy, and medical imaging. Although a thorough assessment to predict potential concerns has to precede before practical utilization of THz source, the biological effect of THz radiation is not yet fully understood with scant related investigations. Here, we applied a femtosecond-terahertz (fs-THz) pulse to mouse skin to evaluate non-thermal effects of THz radiation. Analysis of the genome-wide expression profile in fs-THz-irradiated skin indicated that wound responses were predominantly mediated by transforming growth factor-beta (TGF-β) signaling pathways. We validated NFκB1- and Smad3/4-mediated transcriptional activation in fs-THz-irradiated skin by chromatin immunoprecipitation assay. Repeated fs-THz radiation delayed the closure of mouse skin punch wounds due to up-regulation of TGF-β. These findings suggest that fs-THz radiation initiate a wound-like signal in skin with increased expression of TGF-β and activation of its downstream target genes, which perturbs the wound healing process in vivo.

TLR4, rather than TLR2, regulates wound healing through TGF-β and CCL5 expression

BACKGROUND

Toll-like receptors (TLRs) have a crucial role in early host defense against invading pathogens. Recent studies suggest that TLRs play important roles in non-infections inflammation and tissue repair and regeneration.

OBJECTIVE

To determine the roles of TLR2 and TLR4 in mouse wound healing using TLR2-deficient (TLR2(-/-)), TLR4-deficient (TLR4(-/-)), and TLR2/TLR4-deficient (TLR2/4(-/-)) mice.

METHODS

Open wounds made in TLR2(-/-), TLR4(-/-), and TLR2/4(-/-) mice were examined clinically and histologically. Cytokine expression in the wounded skin was also investigated. TGF-β production from macrophages stimulated by hyaluronan, a ligand for TLR2 and TLR4, was evaluated by real-time PCR.

RESULTS

Wound areas in TLR2(-/-), TLR4(-/-), and TLR2/4(-/-) mice were larger than wild-type mice both at days 3 and 7 after wounding, accompanied by decreased numbers of infiltrating macrophages in the dermis and decreased TGF-β and CCL5 mRNA expression in the wounded skin. Immunohistochemistry showed decreased numbers of macrophages expressing TGF-β and reduced CCL5 expression by keratinocytes in the wounded skin from TLR2(-/-), TLR4(-/-), and TLR2/4(-/-) mice compared to wild-type mice. Moreover, TGF-β production from macrophages induced by hyaluronan stimulation in vitro was significantly decreased in the absence of TLRs, especially TLR4. Interestingly, macrophages and wounded skin from TLR2(-/-) mice showed decreased TLR4 mRNA expression compared to wild-type mice, suggesting that the effect of TLR2 deficiency was at least partially dependent on decrease in TLR4. Topical application of TGF-β and CCL5 significantly improved wound healing in TLR-deficient mice.

CONCLUSION

TLR4, rather than TLR2, regulates wound healing through TGF-β and CCL5 expression.

Fibrosis-associated single-nucleotide polymorphisms in TGFB1 and CAV1 are not associated with the development of nephrogenic systemic fibrosis

OBJECTIVE

To test the hypothesis that the subset of patients with impaired renal function who are exposed to gadolinium-containing contrast agents (GCCAs) and develop nephrogenic systemic fibrosis (NSF) have a genetic predisposition for disease.

METHODS

We examined whether an intronic single-nucleotide polymorphism (SNP) in caveolin-1 (CAV1 rs4730751) and 2 coding SNPs in transforming growth factor-beta 1 (TGFB1 rs1800471, codon 25; and rs1800470, codon 10) were associated with the NSF phenotype.

RESULTS

Forty-one patients with a history of chronic kidney disease and GCCA administration were studied, including NSF cases (n = 17) and control subjects (n = 24) without clinical or histological evidence of NSF. No significant differences in the genotype frequencies at these SNPs in TGFB1 and CAV1 were found between patients with NSF and subjects without NSF.

CONCLUSIONS

We conclude that polymorphisms in the genes encoding TGFB1 and CAV1 previously associated with the development and progression of fibrosis in several organ systems are not associated with development of NSF in this cohort of patients with renal impairment after GCCA exposure.

Interleukin-10 reduces scar formation in both animal and human cutaneous wounds: results of two preclinical and phase II randomized control studies

Cutaneous scarring affects up to 100 million people per annum. There is no effective scar reducing/preventing therapeutic developed to date. Interleukin (IL)-10 is an anti-inflammatory and antifibrotic cytokine. In the embryo it is important for scarless wound repair. We investigated the effect on wound healing and scarring of a double deletion of the IL-10 and IL-4 genes in a knockout (KO) mouse model, and also the effect of exogenous addition of recombinant human (rh) IL-10 into rat and human cutaneous incisions. Mouse study: Two incisions were made on the dorsal skin of 20 double IL-4/IL-10 KO mice and 20 wild-type (WT) controls. Rat study: Three concentrations of rhIL-10 were investigated. Four incisions were made on the dorsal skin of 30 rats. Each rat received two concentrations. Each incision receiving a concentration of rhIL-10 was matched with a control incision, which received either placebo or standard care. Human study: Eight concentrations of rhIL-10 were investigated. Four incisions were made on each arm of 175 healthy volunteers. Four incisions received four different concentrations, which were matched with four control incisions that received either standard care or placebo. KO mice healed with poor scar histology and increased inflammation. rhIL-10-treated rat incisions healed with decreased inflammation, better scar histology, and better macroscopic scar appearance. rhIL-10-treated human incisions at low concentrations healed with better macroscopic scar appearance and less red scars. IL-10 is an important cytokine in wound healing and its suppression of inflammation and scarring is demonstrated in mice and rats with a translational effect in humans.

TGF-β1 T869C polymorphism may affect susceptibility to idiopathic pulmonary fibrosis and disease severity

BACKGROUND

Transforming growth factor-β1 (TGF-β1) is a key cytokine that plays a critical role in idiopathic pulmonary fibrosis (IPF). The genotypes of T869C polymorphism may be associated with the susceptibility to fibrotic lung disease.

METHODS

We investigated a single-nucleotide polymorphism at exon 1 nucleotide position 29 (T → C) of the TGF-β1 gene. Eighty-five healthy controls and 85 subjects with surgically confirmed IPF were investigated using polymerase chain reaction and restriction enzyme fragment length polymorphism techniques.

RESULTS

The IPF patients consisted of 55 men and 30 women. The mean age was 61 ± 8 years. Fifty-one (60 %) of the 85 IPF patients were smokers and 34 were nonsmokers. The distribution of genotypes between IPF patients and controls was significantly different (IPF: TT 43.5 % and TC or CC 56.5 %; controls: TT 27.1 % and TC or CC 72.9 %, p = 0.037). TT genotype was significantly associated with decreased PaO2 and increased D(A-a)O2 upon initial diagnosis (p = 0.006 and 0.009, respectively). There was a positive association between TT genotype and IPF development (odds ratio [OR] = 2.1, 95 % confidence interval [CI] = 1.1-4.0, p = 0.028).

CONCLUSIONS

This study suggests that the TGF-β1 gene T869C polymorphism may affect susceptibility to IPF in Koreans. Larger studies are required to confirm the genetic association of TGF-β1 gene polymorphism and IPF.

Abnormal pigmentation within cutaneous scars: A complication of wound healing

Abnormally pigmented scars are an undesirable consequence of cutaneous wound healing and are a complication every single individual worldwide is at risk of. They present a challenge for clinicians, as there are currently no definitive treatment options available, and render scars much more noticeable making them highly distressing for patients. Despite extensive research into both wound healing and the pigment cell, there remains a scarcity of knowledge surrounding the repigmentation of cutaneous scars. Pigment production is complex and under the control of many extrinsic and intrinsic factors and patterns of scar repigmentation are unpredictable. This article gives an overview of human skin pigmentation, repigmentation following wounding and current treatment options.

TGF-β-responsive myeloid cells suppress type 2 immunity and emphysematous pathology after hookworm infection

Transforming growth factor β (TGF-β) regulates inflammation, immunosuppression, and wound-healing cascades, but it remains unclear whether any of these functions involve regulation of myeloid cell function. The present study demonstrates that selective deletion of TGF-βRII expression in myeloid phagocytes i) impairs macrophage-mediated suppressor activity, ii) increases baseline mRNA expression of proinflammatory chemokines/cytokines in the lung, and iii) enhances type 2 immunity against the hookworm parasite Nippostrongylus brasiliensis. Strikingly, TGF-β-responsive myeloid cells promote repair of hookworm-damaged lung tissue, because LysM(Cre)TGF-βRII(flox/flox) mice develop emphysema more rapidly than wild-type littermate controls. Emphysematous pathology in LysM(Cre)TGF-βRII(flox/flox) mice is characterized by excessive matrix metalloprotease (MMP) activity, reduced lung elasticity, increased total lung capacity, and dysregulated respiration. Thus, TGF-β effects on myeloid cells suppress helminth immunity as a consequence of restoring lung function after infection.

Prospective ex-vivo study on thermal effects in human skin phototypes II, IV and VI: a comparison between the 808, 1064, 1210 and 1320-nm diode laser

BACKGROUND

Laser Assisted Skin Healing (LASH) was first introduced in 2001 by Capon and Mordon to prevent keloids and hypertrophic scars. LASH requires homogenous heating throughout the full thickness of the skin around the wound. However, LASH therapy with 808-nm diode laser is deemed to be only applicable for phototype I-IV due to melanin absorption. This prospective ex-vivo study aims to evaluate the thermal effects of different wavelengths (808, 1064, 1210 and 1320 nm) on human skin phototype II, IV and VI.

MATERIAL AND METHODS

Laser shots were applied on skin explants phototypes II, IV and VI. The following laser settings were used: 808, 1064, 1210 and 1320-nm diode laser, Spot size 20 × 3.7 mm, Power 3 W, Irradiance 4 W/cm², 50 shots for each phototype and wavelength. The surface temperature at 2 and 4-mm depth respectively was evaluated by an infrared camera and a low inertia micro thermocouple.

RESULTS

For the 1064, 1210 and 1320-nm wavelengths, the temperature gradient between the surface and 2-mm depth after an irradiation time of 15 s was less than 4.0°C for each phototype. For the 808 nm, the gradient was 0.8°C and 4.4°C in phototype II and IV respectively, but reached 17.2°C in phototype VI. Strong absorption by melanin of skin phototype VI induced unwanted temperature increases at the dermis-epidermis junction, making this wavelength unsuitable for LASH therapy for this phototype. Among the three other wavelengths, the discussion section indicates strong blood absorption at 1064 nm and presents both 1210 and 1320 nm as excellent compromises for LASH therapy across the whole range of phototypes.

CONCLUSION

Being poorly absorbed by melanin, both 1210 and 1320-nm wavelengths ensure homogeneity of temperature throughout the full skin explant thickness. Their possible utilization for efficient LASH therapy should now be confirmed by prospective in vivo studies.

The healing and anti-scar effects of astragaloside IV on the wound repair in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Astragaloside IV is the chief ingredient of Radix Astragali, which has been used in the Traditional Chinese Medicine as a major component of many polyherbal formulations for the repair and regeneration of injured organ and tissues. This study is to investigate the influence of astragaloside IV on both of the wound healing and scar formation.

MATERIALS AND METHODS

For the in vitro evaluation, the influence of the astragaloside IV in the wound scratch test of keratinocytes and the secretion of transforming growth factor-β1, a key factor contributing to scar formation were determined. With the rat skin excision model, the in vivo regulation of astragaloside IV on wound closure, angiogenesis and collagen disposition were also evaluated.

RESULTS

Astragaloside IV was shown to significantly promote the migration of keratinocytes in wound scratching assay. The superior effect of Astragaloside IV was observed at 100 μmol/L, in which the recover rates was increased with 2 and 3 folds after 48 h and 96 h respectively than that of blank control (P<0.01). Animal skin closure measurement showed that astragaloside IV could stimulate the wound healing, e.g. with 21% recover in contrast to the 8% of blank control at the 6th day. Biomechanic and Masson's trichrome stain analysis indicated that astragaloside IV may improve the strength of the repaired skin and promoted the angiogenesis and collagen synthesis. Meanwhile, the picrosirius-sirus red stain and Elisa test definitely showed the anti-scar effects of astragaloside IV by decreasing the levels of collagen I/III and TGF-β1 secretion by firbroblasts with a dose-dependent manner (25-100 μmol/L).

CONCLUSIONS

Astragaloside IV was shown a promising natural product with both healing and anti-scar effects for wound treatment. These results give the evidence for the application of astragaloside IV in the treatment of injury.

Collagen-binding peptidoglycans inhibit MMP mediated collagen degradation and reduce dermal scarring

Scarring of the skin is a large unmet clinical problem that is of high patient concern and impact. Wound healing is complex and involves numerous pathways that are highly orchestrated, leaving the skin sealed, but with abnormal organization and composition of tissue components, namely collagen and proteoglycans, that are then remodeled over time. To improve healing and reduce or eliminate scarring, more rapid restoration of healthy tissue composition and organization offers a unique approach for development of new therapeutics. A synthetic collagen-binding peptidoglycan has been developed that inhibits matrix metalloproteinase-1 and 13 (MMP-1 and MMP-13) mediated collagen degradation. We investigated the synthetic peptidoglycan in a rat incisional model in which a single dose was delivered in a hyaluronic acid (HA) vehicle at the time of surgery prior to wound closure. The peptidoglycan treatment resulted in a significant reduction in scar tissue at 21 days as measured by histology and visual analysis. Improved collagen architecture of the treated wounds was demonstrated by increased tensile strength and transmission electron microscopy (TEM) analysis of collagen fibril diameters compared to untreated and HA controls. The peptidoglycan's mechanism of action includes masking existing collagen and inhibiting MMP-mediated collagen degradation while modulating collagen organization. The peptidoglycan can be synthesized at low cost with unique design control, and together with demonstrated preclinical efficacy in reducing scarring, warrants further investigation for dermal wound healing.

Regeneration of skeletal muscle

Skeletal muscle has a robust capacity for regeneration following injury. However, few if any effective therapeutic options for volumetric muscle loss are available. Autologous muscle grafts or muscle transposition represent possible salvage procedures for the restoration of mass and function but these approaches have limited success and are plagued by associated donor site morbidity. Cell-based therapies are in their infancy and, to date, have largely focused on hereditary disorders such as Duchenne muscular dystrophy. An unequivocal need exists for regenerative medicine strategies that can enhance or induce de novo formation of functional skeletal muscle as a treatment for congenital absence or traumatic loss of tissue. In this review, the three stages of skeletal muscle regeneration and the potential pitfalls in the development of regenerative medicine strategies for the restoration of functional skeletal muscle in situ are discussed.

Keloid skin scars: the influence of hyperbaric oxygenation on fibroblast growth and on the expression of messenger RNA for insulin like growth factor and for transforming growth factor

Wound healing can result in the development of keloid scars that contain atypical fibroblasts and an overabundance of extracellular matrix components. Hyperbaric oxygenation (HBO) refers to exposure to pure oxygen under increased atmospheric pressure and is recognized as a valuable supplementary method of treatment for problematic wounds. The effect of HBO in the expression of insulin-like growth factor type 1 (ILGF-1) and transforming growth factor β (TGF-β) messenger RNAs was determined by semiquantitative RT-PCR in fibroblasts obtained from keloid scars and nonwound involved skin fibroblast from the same patient. ILGF-1 and TGF-β are the principal mitogens during wound regeneration. We found a decrease in the growth of fibroblasts and in the expression of ILGF-1 and TGF-β messengers in keloid and nonkeloid fibroblast after chronic exposition to hyperbaric oxygenation compared with normal oxygen partial pressure.

The evidence for the role of transforming growth factor-beta in the formation of abnormal scarring

The complex biological and physiological mechanisms that result in poor quality scarring are still not fully understood. This review looks at current evidence of the role of transforming growth factor-beta (TGFβ) in this pathological process.

Scar prevention using Laser-Assisted Skin Healing (LASH) in plastic surgery

BACKGROUND

The use of lasers has been proposed for scar revision. A recent pilot clinical study demonstrated that lasers could also be used immediately after surgery to reduce the appearance of scars. The LASH (Laser-Assisted Skin Healing) technique induces a temperature elevation in the skin which modifies the wound-healing process. We report a prospective comparative clinical trial aimed at evaluating an 810-nm diode-laser system to accelerate and improve the healing process in surgical scars immediately after skin closure.

METHODS

Twenty-nine women and 1 man (mean age = 41.4 years; Fitzpatrick skin types I-IV) were included to evaluate the safety and performance of the laser system. The laser dose (or fluence in J/cm(2)) was selected as a function of phototype and skin thickness. Each surgical incision (e.g., abdominoplasty) was divided into two parts. An 8-cm segment was treated with the laser immediately after skin closure. A separate 8-cm segment was left untreated as a control. Clinical evaluations (overall appearance ratings, comparative scar scale) of all scars were conducted at 10 days, 3 months, and 12 months by both surgeon and patients. Profilometry analysis from silicone replicas of the skin was done at 12 months. Wilcoxon signed-rank test analyses were performed.

RESULTS

Twenty-two patients were treated using a high dose (80-130 J/cm(2)) and 8 patients with a low dose (<80 J/cm(2)). At 12 months in the high-dose group, both surgeon and patients reported an improvement rate of the laser-treated segment over the control area of 72.73 and 59.10%, respectively. For these patients, profilometry results showed a decrease in scar height of 38.1% (p = 0.027) at 12 months for the laser-treated segment versus control. Three patients treated with higher doses (>115 J/cm(2)) experienced superficial burns on the laser-treated segment, which resolved in about 5-7 days. For the eight patients treated at low dosage (<80 J/cm(2)), there was no significant difference in the treated segment versus the control segment. No side effects were observed.

CONCLUSION

This prospective comparative trial demonstrates that an 810-nm diode laser treatment, performed immediately after surgery, can improve the appearance of a surgical scar. The dose plays a great role in scar improvement and must be well controlled. There is interest in LASH for hypertrophic scar revision. LASH can be used to prevent and reduce scars in plastic surgery.

Platelet-rich fibrin versus albumin in surgical wound repair: a randomized trial with paired design

OBJECTIVE

To study the effects of autologous platelet-rich fibrin (PRF) versus human albumin on incisional wound breaking strength and subcutaneous collagen deposition in patients undergoing laparoscopic cholecystectomy in a randomized trial.

SUMMARY BACKGROUND DATA

Platelet peptidic growth factors may stimulate collagen synthesis and tissue repair.

METHODS

One expanded polytetrafluoroethylene (ePTFE) tube was inserted subcutaneously from the edge of each of the two 10-mm trocar incisions in 51 patients. Treatment with PRF prepared from the patient's own blood or human albumin was randomized to respective wound site by concealed allocation. On postoperative day 10, breaking strength of the incisional wounds as well as the collagen concentration, type I procollagen mRNA, type III procollagen mRNA, matrix metalloproteinase-1 mRNA, and fibroblast density in the ePTFE tubes were determined. All analyses were assessor-blinded. The trial was registered in the Current Controlled Trials Registry (ISRCTN34481461).

RESULTS

Local PRF had no significant effect on incisional wound-breaking strength. In the ePTFE tubes, PRF treatment decreased collagen concentration by 24% (P=0.046) and type I procollagen mRNA level by 29% (P=0.003), but had no significant impact on type III procollagen mRNA, matrix metalloproteinase-1 mRNA or fibroblast infiltration. The profibrotic transforming growth factor-beta1 level increased (P<0.0001) 2-fold with PRF. Collagen concentration in albumin-treated ePTFE tubes correlated with breaking strength of the skin incisions (rs=0.48, P=0.03).

CONCLUSIONS

PRF did not improve wound strength significantly compared with albumin but suppressed subcutaneous collagen synthesis and deposition during early repair of surgical wounds in humans. Furthermore, deposition of reparative collagen in the subcutaneous ePTFE tube model partly predicted the breaking strength of an incisional skin wound.

Laser-assisted skin healing (LASH) in hypertrophic scar revision

Laser-Assisted Skin Healing (LASH) is based on the therapeutic effects of controlled thermal post-conditioning. The authors have previously demonstrated on humans that an 810-nm diode-laser system could assist wound closure leading to an improvement of wound healing with a resulting indiscernible scar. A 47-year-old woman (skin type II), who developed systematically hypertrophic scars after surgery, was enrolled for a hypertrophic scar revision. Excess scar tissue was removed. Immediately after the conventional closure of the incision, laser irradiation (120 J/cm(2)) using a 0.8 cm(2) spot size (rectangular spot, length = 20 mm, width = 4 mm) was applied. Topical silicone gel sheeting (Cerederm((R))) was applied for 2 months afterwards to prevent a thick scar from reforming. No complications occurred during the course of this study. No recurrence of hypertrophic scarring was noticed 6 months after scar revision. This study reports, for the first time, the possibility of improving the appearance of hypertrophic scarring in scar revision by altering through thermal stress the wound-healing process. Since the appropriate initial management of wounds is of importance, the LASH technique could be offered as a new approach to prevent hypertrophic scarring.

Decreased collagen and increased matrix metalloproteinase-13 in experimental abdominal aortic aneurysms in males compared with females

BACKGROUND

This study examined differences in sex in collagen regulation during rodent experimental abdominal aortic aneurysm formation.

METHODS

Infrarenal aortas of male and female rats were perfused with elastase or saline (control). Aortic diameters were measured at baseline (day 0) and on postoperative days 7 and 14. Transforming growth factor-beta 1, collagen subtypes I and III, and matrix metalloproteinase-13 (MMP-13; collagenase-3) expression and/or protein levels from aortic tissue were determined by real-time reverse transcription polymerase chain reaction and Western blotting. Aortic tissue was stained for total collagen, neutrophils, and macrophages using immunohistochemistry on days 4 and 7.

RESULTS

At 7 and 14 days after perfusion, aortic diameter increased in elastase-perfused males compared with females (P < .001 for each). At 4 and 7 days postperfusion, significantly more neutrophils and macrophages were present in elastase-perfused males compared with females. By 7 days postperfusion, protein levels of transforming growth factor-beta 1 were less in males compared with females (P = .04). Type I collagen levels also decreased on days 7 (P < .001) and 14 (P = .002), and type III collagen levels decreased on days 7 (P < .001) and 14 (P < .001) in males compared with females. With Masson's trichrome stain, less adventitial collagen was observed in the elastase-perfused males compared with females. MMP-13 expression (P < .001) and protein levels (P = .006) in elastase-perfused males were greater than females on day 14.

CONCLUSION

This study documents a decrease in types I and III collagen with a concurrent increase in MMP-13 after elastase perfusion in males compared with females. These data suggest that alterations in extracellular matrix collagen turnover may be responsible for altered abdominal aortic aneurysm formation between sexes.

A comparative study of the effects of ab externo superpulse carbon dioxide laser-assisted trabeculectomy with conventional trabeculectomy in rabbits

OBJECTIVE

The aim of this investigation was to evaluate the efficacy of reduction in intraocular pressure (IOP) and complications in ab externo superpulse carbon dioxide laser-assisted trabeculectomy.

BACKGROUND

Reduction of IOP remains the immediate goal of glaucoma treatment. Although trabeculectomy has been considered the gold standard for the surgical treatment of glaucoma, many complications are associated with this procedure. Laser surgery has been studied as an alternative way to control IOP in glaucoma.

MATERIALS AND METHODS

Sixty adult albino rabbits were enrolled in this study. The animals underwent one unilateral surgery of either trabeculectomy or ab externo superpulse carbon dioxide laser-assisted trabeculectomy and were divided into two subgroups, control or experimental. Follow-up examinations included ocular anterior segments, filtration blebs and IOP. Five eyes in each group were analyzed histologically one month postoperatively.

RESULTS

Anterior chamber hyphema in the laser group was milder than that in the surgery group, and disappeared on the third day. In the surgery group, it disappeared by the end of the first month. Filtration blebs in the laser group formed earlier than in the surgery group. Comparing the laser group and the surgery group, IOP values in the laser group were more stable. Histological examination showed that the sclera tract was blocked by scar tissue, inflammation had infiltrated, and the anterior chamber angle had adhered in the surgery group.

CONCLUSIONS

Ab externo superpulse carbon dioxide laser-assisted trabeculectomy was suggested as a feasible technique to control IOP with the advantages of more steady IOP reduction and fewer complications.

Longitudinal changes in plasma Transforming growth factor beta-1 and post-burn scarring in children

Transforming growth factor beta1, a multifunctional growth factor, plays a pivotal role in wound healing and has been shown to accelerate impaired wound healing. However, high systemic levels of Transforming growth factor beta1 have generally been associated with fibrotic disease processes such as myelofibrosis and pulmonary fibrosis. Hypertrophic scarring occurring during childhood interferes with growth, impairs the function and causes immense psychological and aesthetic problems. Burns is the leading cause of hypertrophic scarring. We studied the longitudinal relationship between plasma Transforming growth factor beta-1 and post-burn wound healing and scarring in children. We discovered that the plasma levels of Transforming growth factor beta-1 rapidly increased to significantly higher levels in the first two weeks post-injury and fell thereafter, in patients who healed with good quality scars post-burn. By contrast, the increase in plasma TGFbeta1 levels in the early stages after-burn, was noticeably absent in patients who developed hypertrophic scarring. We propose that this change in the systemic levels of TGFbeta1 early after the burn may be used as an indicator of patients at risk of developing hypertrophic burn scars. This group of patients could then be targeted for early pharmacological/physical interventions to reduce/prevent scar-related morbidity in burn survivors.

Loss of dioxin-receptor expression accelerates wound healing in vivo by a mechanism involving TGFbeta

Delayed wound healing caused by inefficient re-epithelialization underlines chronic skin lesions such as those found in diabetes. The dioxin receptor (AhR) modulates cell plasticity and migration and its activation by occupational polycyclic aromatic hydrocarbons (PAHs) results in severe skin lesions such as contact hypersensitivity, dermatitis and chloracne. Using wild-type (Ahr+/+) and AhR-null (Ahr-/-) mouse primary keratinocyte cultures and tissue explants, we show that lack of AhR increases keratinocyte migration and accelerates skin re-epithelialization without affecting cell proliferation or recruitment of inflammatory cells. Wounds in Ahr-/- animals had elevated numbers of fibroblasts and increased collagen content in their granulation tissue. Importantly, Ahr-/- dermal fibroblasts secreted higher levels of active TGFbeta that increased keratinocyte migration in culture and that could account for over-activation of the TGFbeta pathway and for faster wound healing in the AhR-null neo-epithelium. Consistently, a TGFbeta neutralizing antibody decreased keratinocyte migration in culture and halted re-epithelialization in Ahr-/- mice. Moreover, in vivo treatment with an antisense oligonucleotide for AhR increased TGFbeta signaling and improved re-epithelialization in wounds of wild-type mice. These data indicate that AhR is relevant for wound repair and suggest that AhR downmodulation might be a potential new tool for the treatment of chronic, surgical or accidental wounds.

Tyrosine phosphorylation of EGF-R and PDGF-R proteins during acute cutaneous wound healing process in mice

The effect of topical application of epidermal growth factor (EGF) and platelet-derived growth factors (PDGFs) on the levels of EGF-R and PDGF-R proteins and their tyrosine phosphorylation were analyzed during an acute cutaneous wound healing process in mice. The growth factor-treated wounds had optimum levels of receptor proteins as early as day 1 compared with the control, which had only a basal level. Analysis of the tyrosine phosphorylation of the receptor proteins in control and growth factor-treated wounds indicated that they were phosphorylated until day 5 after wounding. Only the mature forms of alpha-PDGF-R and beta-PDGF-R proteins were phosphorylated and not their precursors. Our results show that rapid attainment of maximum levels of growth factor receptor proteins and their tyrosine phosphorylation as early as day 1 and the maintenance of the same until day 3 appear to aid faster and better wound healing. Topical application of PDGF-AA alone did not facilitate the wound healing process and it also antagonized the EGF-medicated wound healing when applied premixed with EGF or within 30 minutes after EGF application. Under these conditions, the receptor proteins were not phosphorylated. Thus, an increased and sustained level of EGF-R and PDGF-R proteins and their tyrosine phosphorylation appear to accelerate the wound healing process.