Thrombospondin in Early Human Wound Tissue

We examined partial thickness incised human wounds of 2, 3, 5, 7, and 14 days of age for the presence of thrombospondin by immunostaining and light microscopy. At 2, 3, 5, and 7 days after wounding, thrombospondin is present primarily at the cut edges of the lateral and deep margins of the wound. It appears to be cleared from these extracellular matrix sites, and is no longer detectable in those sites in most 14-day-old wounds. Thrombospondin staining is present, however, in increased amounts around the vascular channels within and adjacent to the 7- and 14- day wounds in increased amounts relative to vascular channels distant from the wound. Our observations are consistent with known in vitro data regarding the binding of thrombospondin to fibrin and components of the extracellular matrix, as well as with data showing that proliferating endothelial cells secrete more thrombospondin than quiescent endothelial cells. These data support the hypothesis that thrombospondin plays a role in the early organization of the extracellular matrix of wounds

Staphylococcus aureus Biofilm and Planktonic cultures differentially impact gene expression, mapk phosphorylation, and cytokine production in human keratinocytes

<p>Abstract</p> <p>Background</p> <p>Many chronic diseases, such as non-healing wounds are characterized by prolonged inflammation and respond poorly to conventional treatment. Bacterial biofilms are a major impediment to wound healing. Persistent infection of the skin allows the formation of complex bacterial communities termed biofilm. Bacteria living in biofilms are phenotypically distinct from their planktonic counterparts and are orders of magnitude more resistant to antibiotics, host immune response, and environmental stress. <it>Staphylococcus aureus </it>is prevalent in cutaneous infections such as chronic wounds and is an important human pathogen.</p> <p>Results</p> <p>The impact of <it>S. aureus </it>soluble products in biofilm-conditioned medium (BCM) or in planktonic-conditioned medium (PCM) on human keratinocytes was investigated. Proteomic analysis of BCM and PCM revealed differential protein compositions with PCM containing several enzymes involved in glycolysis. Global gene expression of keratinocytes exposed to biofilm and planktonic <it>S. aureus </it>was analyzed after four hours of exposure. Gene ontology terms associated with responses to bacteria, inflammation, apoptosis, chemotaxis, and signal transduction were enriched in BCM treated keratinocytes. Several transcripts encoding cytokines were also upregulated by BCM after four hours. ELISA analysis of cytokines confirmed microarray results at four hours and revealed that after 24 hours of exposure, <it>S. aureus </it>biofilm induced sustained low level cytokine production compared to near exponential increases of cytokines in planktonic treated keratinocytes. The reduction in cytokines produced by keratinocytes exposed to biofilm was accompanied by suppressed phosphorylation of MAPKs. Chemical inhibition of MAPKs did not drastically reduce cytokine production in BCM-treated keratinocytes suggesting that the majority of cytokine production is mediated through MAPK-independent mechanisms.</p> <p>Conclusions</p> <p>Collectively the results indicate that <it>S. aureus </it>biofilms induce a distinct inflammatory response compared to their planktonic counterparts. The differential gene expression and production of inflammatory cytokines by biofilm and planktonic cultures in keratinocytes could have implications for the formation and persistence of chronic wounds. The formation of a biofilm should be considered in any study investigating host response to bacteria.</p

Protein kinase C spatially and temporally regulates gap junctional communication during human wound repair via phosphorylation of connexin43 on serine368

Phosphorylation of connexin43 (Cx43) on serine368 (S368) has been shown to decrease gap junctional communication via a reduction in unitary channel conductance. Examination of phosphoserine368 (pS368) in normal human skin tissue using a phosphorylation site–specific antibody showed relatively even distribution throughout the epidermal layers. However, 24 h after wounding, but not at 6 or 72 h, pS368 levels were dramatically increased in basal keratinocytes and essentially lost from suprabasal layers adjacent to the wound (i.e., within 200 μm of it). Scratch wounding of primary human keratinocytes caused a protein kinase C (PKC)-dependent increase in pS368 in cells adjacent to the scratch, with a time course similar to that found in the wounds. Keratinocytes at the edge of the scratch also transferred dye much less efficiently at 24 h, in a manner dependent on PKC. However, keratinocyte migration to fill the scratch required early (within <6 h) gap junctional communication. Our evidence indicates that PKC-dependent phosphorylation of Cx43 at S368 creates dynamic communication compartments that can temporally and spatially regulate wound healing

Pitfalls and complications in the treatment of cervical spine fractures in patients with ankylosing spondylitis

Patients with ankylosing spondylitis are at significant risk for sustaining cervical spine injuries following trauma predisposed by kyphosis, stiffness and osteoporotic bone quality of the spine. The risk of sustaining neurological deficits in this patient population is higher than average. The present review article provides an outline on the specific injury patterns in the cervical spine, diagnostic algorithms and specific treatment modalities dictated by the underlying disease in patients with ankylosing spondylitis. An emphasis is placed on the risks and complication patterns in the treatment of these rare, but challenging injuries

Ultrastructural Localization of Integrin Subunits β4 and α3 Within the Migrating Epithelial Tongue of In Vivo Human Wounds

Subsequent to wounding, keratinocytes must quickly restore barrier function. In vitro wound models have served to elucidate mechanisms of epithelial closure and key roles for integrins α6β4 and α3β1. To extrapolate in vitro data to in vivo human tissues, we used ultrathin cryomicrotomy to simultaneously observe tissue ultrastructure and immunogold localization in unwounded skin and acute human cutaneous wounds. Localization of the β4 integrin subunit in unwounded skin shows dominant hemidesmosomal association and minor basal keratinocyte lateral filopodic cell–cell expression. After wounding, β4 dominantly localized to cytokeratin-rich regions (trailing edge hemidesmosomes) and minor association with lamellipodia (leading edge). β4 colocalizes with α3 within filopodia juxtaposed to wound matrix, and increased concentrations of β4 were found in cytoplasmic vesicles within basal keratinocytes of the migrating tongue. α3 integrin subunit dominantly localized to filopodia within basal keratinocyte lateral cell–cell interfaces in unwounded skin and both cell–cell and cell–matrix filopodic interactions in wounded skin. This study indicates that β4 interacts with the extracellular environment through both stable and transient interactions and may be managed through a different endosomal trafficking pathway than α3. α3 integrin, despite its ability to respond to alternate ligands after wounding, does so through a single structure, the filopodia. (J Histochem Cytochem 57:123–142, 2009

Cutaneous angiosarcoma clinically presenting as progressive solid facial edema in a 43-year-old male

Cutaneous angiosarcoma of the head and neck is a rare, highly malignant neoplasm; prognosis is heavily influenced by tumor size, resectability, and stage at initial diagnosis. Most patients present with one to several erythematous to violaceous patches, plaques, or nodules. However, the clinical presentation is highly variable and leads to delayed diagnosis. We report cutaneous angiosarcoma in a 43-year-old man who presented with an 11-month history of progressive solid (non-pitting) edema involving his entire face, scalp, eyelids, and neck without characteristic clinical features of cutaneous angiosarcoma. A skin biopsy had shown non-specific findings consistent with solid facial edema or rosacea. Various etiologies were considered but there was no significant improvement after directed medical therapy. Repeat skin biopsies revealed angiosarcoma involving the dermis and sub-cutis. Computed tomography (CT) of the chest showed multiple lung nodules bilaterally and a lytic lesion in the T6 vertebra consistent with metastases. He was treated with single agent chemotherapy (paclitaxel), and had a partial response that restored his ability to open both eyes spontaneously; However, his edema has recently progressed 7 months after diagnosis. This is a rare example of cutaneous angiosarcoma presenting as progressive solid facial edema, which underscores the diverse range of clinical manifestations associated with this neoplasm