Toward understanding scarless skin wound healing and pathological scarring

The efficient healing of skin wounds is crucial for securing the vital barrier function of the skin, but pathological wound healing and scar formation are major medical problems causing both physiological and psychological challenges for patients. A number of tightly coordinated regenerative responses, including haemostasis, the migration of various cell types into the wound, inflammation, angiogenesis, and the formation of the extracellular matrix, are involved in the healing process. In this article, we summarise the central mechanisms and processes in excessive scarring and acute wound healing, which can lead to the formation of keloids or hypertrophic scars, the two types of fibrotic scars caused by burns or other traumas resulting in significant functional or aesthetic disadvantages. In addition, we discuss recent developments related to the functions of activated fibroblasts, the extracellular matrix and mechanical forces in the wound environment as well as the mechanisms of scarless wound healing. Understanding the different mechanisms of wound healing is pivotal for developing new therapies to prevent the fibrotic scarring of large skin wounds.publishedVersio

Out of the darkness: A History of Huntington's Disease in Australia

Huntington’s disease (HD) is a genetic neurological condition which has a profound influence on the families it affects. The symptoms of the disease are challenging – in addition, social forces strongly influence the way the disease is experienced. It has been a deeply stigmatised condition, and its presence was often kept secret. In this dissertation, I have explored both social and medical aspects of the history of HD, primarily in Australia, building on the work of two scholars, Peter Harper (UK) and Alice Wexler (US). By tracing the histories of HD families, I discovered that HD has been part of the fabric of life in Australia since the convict era, and that some families with the disease were well-respected in their communities, in contrast to narratives which have presented the stigma as inevitable. Wexler has previously shown that in the US, the degree of stigma faced by HD families has varied over time, and my research found this to be also true of the disease in Australia. The earliest descriptions of the disease in the US were mostly made by physicians familiar with HD families. My research revealed a similar story - two physicians who published on HD both grew up in an area of Tasmania with relatively high rates of the disease. The impact of eugenic thinking in the stigmatization of HD in the US, Germany and the UK was noted more than 20 years ago, though its impact in other countries has remained unexplored. Eugenics as a formal movement was not successful in Australia, however eugenic ideas formed part of the social discourse. I show through medical journal articles, items in the popular press and educational organisations how those with hereditary diseases were labeled as “unfit”, promoting stigma which contributed to it being hidden. Finally I describe how the disease began to emerge from “the closet” in the early 1970s, with families and researchers forging a new collaboration to search for treatments, support families and reduce stigma

A simple mechanistic model of sprout spacing in tumour-associated angiogenesis

This paper develops a simple mathematical model of the siting of capillary sprouts on an existing blood vessel during the initiation of tumour-induced angiogenesis. The model represents an inceptive attempt to address the question of how unchecked sprouting of the parent vessel is avoided at the initiation of angiogenesis, based on the idea that feedback regulation processes play the dominant role. No chemical interaction between the proangiogenic and antiangiogenic factors is assumed. The model is based on corneal pocket experiments, and provides a mathematical analysis of the initial spacing of angiogenic sprouts

Complement Component C3 and Complement Factor B Promote Growth of Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma (cSCC) is one of the most common metastatic skin cancers with increasing incidence. We examined the roles of complement component C3 and complement factor B (CFB) in the growth of cSCC. Analysis of cSCC cell lines (n = 8) and normal human epidermal kerati-nocytes (n = 11) with real-time quantitative PCR and Western blotting revealed up-regulation of C3 and CFB expression in cSCC cells. Immunohistochemical staining revealed stronger tumor cell specific Labeling for C3 and CFB in invasive cSCCs (n = 71) and recessive dystrophic epidermolysis bullosa-associated cSCCs (n = 11) than in cSCC in situ (n = 69), actinic keratoses (n = 63), and normal skin (n = 5). Significant up-regulation of C3 and CFB mRNA expression was noted in chemically induced mouse cSCCs, compared to benign papillomas. Knockdown of C3 and CFB expression inhibited migration and proliferation of cSCC cells and resulted in potent inhibition of extracellular signal regulated kinase 1/2 activation. Knockdown of C3 and CFB markedly inhibited growth of human cSCC xenograft tumors in vivo. These results provide evidence for the rotes of C3 and CFB in the development of cSCC and identify them as biomarkers and potential therapeutic targets in this metastatic skin cancer.Peer reviewe

Haavan paraneminen - diabetes sekä muut esteet ja hidasteet

Krooniset haavat ja haavan paranemisen pitkittyminen ovat merkittäviä kliinisiä ongelmia. Haavan paraneminen on monimutkainen biologinen prosessi, joka voidaan jakaa neljään vaiheeseen: verenvuodon tyrehtymiseen sekä sitä seuraaviin tulehdus-, korjaus- ja kypsymisvaiheisiin, joita säätelevät paikalliset olosuhteet. Haavan paranemiseen vaikuttaa myös yksilön yleistila kaikkine sairauksineen ja lääkityksineen. Paikallisista tekijöistä muun muassa tulehdusreaktiovaiheen pitkittyminen ja huono verenkierto edistävät haavojen kroonistumista. Diabetekseen liittyy huonontunut haavojen paranemistaipumus. Hyperglykemia heikentää haavan paranemista useilla eri mekanismeilla, joista yksi keskeinen perustuu hyperglykemian seurauksena kudoksiin ylimäärin kertyneiden, ei-entsymaattisesti liikaglykosyloituneiden molekyylien (advanced glycosylation end-products, AGE) käynnistämiin solubiologisiin häiriöihin. Paras keino estää hyperglykemian haitallinen vaikutus on tavoitella suositusten mukaista verenglukoosipitoisuutta

Matrix metalloproteinase 9 inhibits the motility of highly aggressive HSC-3 oral squamous cell carcinoma cells

Pro-tumorigenic activities of matrix metalloproteinase (MMP) 9 have been linked to many cancers, but recently the tumour-suppressing role of MMP9 has also been elucidated. The multifaceted evidence on this subject prompted us to examine the role of MMP9 in the behaviour of oral tongue squamous cell carcinoma (OTSCC) cells. We used gelatinase-specific inhibitor, CTT2, and short hairpin (sh) RNA gene silencing to study the effects of MMP9 on proliferation, motility and invasion of an aggressive OTSCC cell line, HSC-3. We found that the migration and invasion of HSC-3 cells were increased by CTT2 and shRNA silencing of MMP9. Proliferation, in turn, was decreased by MMP9 inhibition. Furthermore, arresten-overexpressing HSC-3 cells expressed increased levels of MMP9, but exhibited decreased motility compared with controls. Interestingly, these cells restored their migratory capabilities by CTT2 inhibition of MMP9. Hence, although higher MMP9 expression could give rise to an increased tumour growth in vivo due to increased proliferation, in some circumstances, it may participate in yet unidentified molecular mechanisms that reduce the cell movement in OTSCC.Peer reviewe

Type XVIII collagen degradation products in acute lung injury

Introduction: In acute lung injury, repair of the damaged alveolar-capillary barrier is an essential part of recovery. Endostatin is a 20 to 28 kDa proteolytic fragment of the basement membrane collagen XVIII, which has been shown to inhibit angiogenesis via action on endothelial cells. We hypothesised that endostatin may have a role in inhibiting lung repair in patients with lung injury. The aims of the study were to determine if endostatin is elevated in the plasma/bronchoalveolar lavage fluid of patients with acute lung injury and ascertain whether the levels reflect the severity of injury and alveolar inflammation, and to assess if endostatin changes occur early after the injurious lung stimuli of one lung ventilation and lipopolysaccharide (LPS) challenge. Methods: Endostatin was measured by ELISA and western blotting. Results: Endostatin is elevated within the plasma and bronchoalveolar lavage fluid of patients with acute lung injury. Lavage endostatin reflected the degree of alveolar neutrophilia and the extent of the loss of protein selectivity of the alveolar-capillary barrier. Plasma levels of endostatin correlated with the severity of physiological derangement. Western blotting confirmed elevated type XVIII collagen precursor levels in the plasma and lavage and multiple endostatin-like fragments in the lavage of patients. One lung ventilation and LPS challenge rapidly induce increases in lung endostatin levels. Conclusions: Endostatin may adversely affect both alveolar barrier endothelial and epithelial cells, so its presence within both the circulation and the lung may have a pathophysiological role in acute lung injury that warrants further evaluation

Novel pathogenic mutations and skin biopsy analysis in Knobloch syndrome

Purpose: To facilitate future diagnosis of Knobloch syndrome (KS) and better understand its etiology, we sought to identify not yet described COL18A1 mutations in KS patients. In addition, we tested whether mutations in this gene lead to absence of the COL18A1 gene product and attempted to better characterize the functional effect of a previously reported missense mutation. Methods: Direct sequencing of COL18A1 exons was performed in KS patients from four unrelated pedigrees. We used immunofluorescent histochemistry in skin biopsies to evaluate the presence of type XVIII collagen in four KS patients carrying two already described mutations: c. 3277C>T, a nonsense mutation, and c. 3601G>A, a missense mutation. Furthermore, we determined the binding properties of the mutated endostatin domain p.A1381T (c.3601G>A) to extracellular matrix proteins using ELISA and surface plasmon resonance assays. Results: We identified four novel mutations in COL18A1, including a large deletion involving exon 41. Skin biopsies from KS patients revealed lack of type XVIII collagen in epithelial basement membranes and blood vessels. We also found a reduced affinity of p.A1381T endostatin to some extracellular matrix components. Conclusions: COL18A1 mutations involved in Knobloch syndrome have a distribution bias toward the coding exons of the C-terminal end. Large deletions must also be considered when point mutations are not identified in patients with characteristic KS phenotype. We report, for the first time, lack of type XVIII collagen in KS patients by immunofluorescent histochemistry in skin biopsy samples. As a final point, we suggest the employment of this technique as a preliminary and complementary test for diagnosis of KS in cases when mutation screening either does not detect mutations or reveals mutations of uncertain effect, such as the p.A1381T change.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) - CEPIDConselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq

Significant Role of Collagen XVII And Integrin beta 4 in Migration and Invasion of The Less Aggressive Squamous Cell Carcinoma Cells

Collagen XVII and integrin alpha 6 beta 4 have well-established roles as epithelial adhesion molecules. Their binding partner laminin 332 as well as integrin alpha 6 beta 4 are largely recognized to promote invasion and metastasis in various cancers, and collagen XVII is essential for the survival of colon and lung cancer stem cells. We have studied the expression of laminin.2, collagen XVII and integrin beta 4 in tissue microarray samples of squamous cell carcinoma (SCC) and its precursors, actinic keratosis and Bowen's disease. The expression of laminin.2 was highest in SCC samples, whereas the expression of collagen XVII and integrin beta 4 varied greatly in SCC and its precursors. Collagen XVII and integrin beta 4 were also expressed in SCC cell lines. Virus-mediated RNAi knockdown of collagen XVII and integrin beta 4 reduced the migration of less aggressive SCC-25 cells in horizontal scratch wound healing assay. Additionally, in a 3D organotypic myoma invasion assay the loss of collagen XVII or integrin beta 4 suppressed equally the migration and invasion of SCC-25 cells whereas there was no effect on the most aggressive HSC-3 cells. Variable expression patterns and results in migration and invasion assays suggest that collagen XVII and integrin beta 4 contribute to SCC tumorigenesis.Peer reviewe