Transcriptomes of Wet Skin Biopsies Predict Outcomes after Ionizing Radiation Exposure with Potential Dosimetric Applications in a Mouse Model.

Countermeasures for radiation diagnosis, prognosis, and treatment are trailing behind the proliferation of nuclear energy and weaponry. Radiation injury mechanisms at the systems biology level are not fully understood. Here, mice skin biopsies at h2, d4, d7, d21, and d28 after exposure to 1, 3, 6, or 20 Gy whole-body ionizing radiation were evaluated for the potential application of transcriptional alterations in radiation diagnosis and prognosis. Exposure to 20 Gy was lethal by d7, while mice who received 1, 3, or 6 Gy survived the 28-day time course. A Sammon plot separated samples based on survival and time points (TPs) within lethal (20 Gy) and sublethal doses. The differences in the numbers, regulation mode, and fold change of significantly differentially transcribed genes (SDTGs, p < 0.05 and FC > 2) were identified between lethal and sublethal doses, and down and upregulation dominated transcriptomes during the first post-exposure week, respectively. The numbers of SDTGs and the percentages of upregulated ones revealed stationary downregulation post-lethal dose in contrast to responses to sublethal doses which were dynamic and largely upregulated. Longitudinal up/downregulated SDTGs ratios suggested delayed and extended responses with increasing IR doses in the sublethal range and lethal-like responses in late TPs. This was supported by the distributions of common and unique genes across TPs within each dose. Several genes with potential dosimetric marker applications were identified. Immune, fibrosis, detoxification, hematological, neurological, gastric, cell survival, migration, and proliferation radiation response pathways were identified, with the majority predicted to be activated after sublethal and inactivated after lethal exposures, particularly during the first post-exposure week.

Comparison of Transcriptional Signatures of Three Staphylococcal Superantigenic Toxins in Human Melanocytes.

Staphylococcus aureus, a gram-positive bacterium, causes toxic shock through the production of superantigenic toxins (sAgs) known as Staphylococcal enterotoxins (SE), serotypes A-J (SEA, SEB, etc.), and toxic shock syndrome toxin-1 (TSST-1). The chronology of host transcriptomic events that characterizes the response to the pathogenesis of superantigenic toxicity remains uncertain. The focus of this study was to elucidate time-resolved host responses to three toxins of the superantigenic family, namely SEA, SEB, and TSST-1. Due to the evolving critical role of melanocytes in the host's immune response against environmental harmful elements, we investigated herein the transcriptomic responses of melanocytes after treatment with 200 ng/mL of SEA, SEB, or TSST-1 for 0.5, 2, 6, 12, 24, or 48 h. Functional analysis indicated that each of these three toxins induced a specific transcriptional pattern. In particular, the time-resolved transcriptional modulations due to SEB exposure were very distinct from those induced by SEA and TSST-1. The three superantigens share some similarities in the mechanisms underlying apoptosis, innate immunity, and other biological processes. Superantigen-specific signatures were determined for the functional dynamics related to necrosis, cytokine production, and acute-phase response. These differentially regulated networks can be targeted for therapeutic intervention and marked as the distinguishing factors for the three sAgs.

Transcriptomics of Wet Skin Biopsies Predict Early Radiation-Induced Hematological Damage in a Mouse Model.

The lack of an easy and fast radiation-exposure testing method with a dosimetric ability complicates triage and treatment in response to a nuclear detonation, radioactive material release, or clandestine exposure. The potential of transcriptomics in radiation diagnosis and prognosis were assessed here using wet skin (blood/skin) biopsies obtained at hour 2 and days 4, 7, 21, and 28 from a mouse radiation model. Analysis of significantly differentially transcribed genes (SDTG; p ≤ 0.05 and FC ≥ 2) during the first post-exposure week identified the glycoprotein 6 (GP-VI) signaling, the dendritic cell maturation, and the intrinsic prothrombin activation pathways as the top modulated pathways with stable inactivation after lethal exposures (20 Gy) and intermittent activation after sublethal (1, 3, 6 Gy) exposure time points (TPs). Interestingly, these pathways were inactivated in the late TPs after sublethal exposure in concordance with a delayed deleterious effect. Modulated transcription of a variety of collagen types, laminin, and peptidase genes underlay the modulated functions of these hematologically important pathways. Several other SDTGs related to platelet and leukocyte development and functions were identified. These results outlined genetic determinants that were crucial to clinically documented radiation-induced hematological and skin damage with potential countermeasure applications.

Examining the effect of wound cleansing on the microbiome of venous stasis ulcers.

Common treatment for venous leg wounds includes topical wound dressings with compression. At each dressing change, wounds are debrided and washed; however, the effect of the washing procedure on the wound microbiome has not been studied. We hypothesized that wound washing may alter the wound microbiome. To characterize microbiome changes with respect to wound washing, swabs from 11 patients with chronic wounds were sampled before and after washing, and patient microbiomes were characterized using 16S rRNA sequencing and culturing. Microbiomes across patient samples prior to washing were typically polymicrobial but varied in the number and type of bacterial genera present. Proteus and Pseudomonas were the dominant genera in the study. We found that washing does not consistently change microbiome diversity but does cause consistent changes in microbiome composition. Specifically, washing caused a decrease in the relative abundance of the most highly represented genera in each patient cluster. The finding that venous leg ulcer wound washing, a standard of care therapy, can induce changes in the wound microbiome is novel and could be potentially informative for future guided therapy strategies.

Galectin-1 production is elevated in hypertrophic scar.

Upon healing, burn wounds often leave hypertrophic scars (HTSs) marked by excess collagen deposition, dermal and epidermal thickening, hypervascularity, and an increased density of fibroblasts. The Galectins, a family of lectins with a conserved carbohydrate recognition domain, function intracellularly and extracellularly to mediate a multitude of biological processes including inflammatory responses, angiogenesis, cell migration and differentiation, and cell-ECM adhesion. Galectin-1 (Gal-1) has been associated with several fibrotic diseases and can induce keratinocyte and fibroblast proliferation, migration, and differentiation into fibroproliferative myofibroblasts. In this study, Gal-1 expression was assessed in human and porcine HTS. In a microarray, galectins 1, 4, and 12 were upregulated in pig HTS compared to normal skin (fold change = +3.58, +6.11, and +3.03, FDR <0.01). Confirmatory qRT-PCR demonstrated significant upregulation of Galectin-1 (LGALS1) transcription in HTS in both human and porcine tissues (fold change = +7.78 and +7.90, P <.05). In pig HTS, this upregulation was maintained throughout scar development and remodeling. Immunofluorescent staining of Gal-1 in human and porcine HTS showed significantly increased fluorescence (202.5 ± 58.2 vs 35.2 ± 21.0, P <.05 and 276.1 ± 12.7 vs 69.7 ± 25.9, P <.01) compared to normal skin and co-localization with smooth muscle actin-expressing myofibroblasts. A strong positive correlation (R = .948) was observed between LGALS1 and Collagen type 1 alpha 1 mRNA expression. Gal-1 is overexpressed in HTS at the mRNA and protein levels and may have a role in the development of scar phenotypes due to fibroblast over-proliferation, collagen secretion, and dermal thickening. The role of galectins shows promise for future study and may lead to the development of a pharmacotherapy for treatment of HTS.

Cutaneous Thermal Injury Modulates Blood and Skin Metabolomes Differently in a Murine Model.

As the field of metabolomics develops further, investigations of how the metabolome is affected following thermal injury may be helpful to inform diagnostics and guide treatments. In this study, changes to the metabolome were tested and validated in a murine burn injury model. After a 30% total body surface scald injury or sham procedure sera and skin biopsies were collected at 1, 2, 6, or 24 hr. Burn-specific changes in the metabolome were detected compared to sham animals. The sera metabolome exhibited a more rapid response to burn injury than that of the skin and it peaked more proximal to injury (6 vs 24 hr). Progression of metabolic response in the skin was less synchronous and showed a higher overlap of the significantly modified metabolites (SMMs) among tested time-points. Top affected pathways identified by SMMs of skin included inositol phosphate metabolism, ascorbate and alderate metabolism, caffeine metabolism, and the pentose phosphate pathway. Future research is warranted in human and larger animal models to further elucidate the role of metabolomic perturbations and the pathophysiology following burn injury.

Blood RNA Integrity is a Direct and Simple Reporter of Radiation Exposure and Prognosis: A Pilot Study.

In the event of a mass casualty radiation scenario, rapid assessment of patients' health and triage is required for optimal resource utilization. Identifying the level and extent of exposure as well as prioritization of care is extremely challenging under such disaster conditions. Blood-based biomarkers, such as RNA integrity numbers (RIN), could help healthcare personnel quickly and efficiently determine the extent and effect of multiple injuries on patients' health. Evaluation of the effect of different radiation doses, alone or in combination with burn injury, on total RNA integrity over multiple time points was performed. Total RNA integrity was tallied in blood samples for potential application as a marker of radiation exposure and survival. Groups of aged mice (3-6 mice/group, 13-18 months old) received 0.5, 1, 5, 10 or 20 Gy ionizing radiation. Two additional mouse groups received low-dose irradiation (0.5 or 1 Gy) with a 15% total body surface area (TBSA) burn injury. Animals were euthanized at 2 or 12 h and at day 1, 2, 3, 7 or 14 postirradiation, or when injury-mediated mortality occurred. Total RNA was isolated from blood. The quality of RNA was evaluated and RNA RIN were obtained. Analysis of RIN indicated that blood showed the clearest radiation effect. There was a time- and radiation-dose-dependent reduction in RIN that was first detectable at 12 h postirradiation for all doses in animals receiving irradiation alone. This effect was reversible in lower-dose groups (i.e., 0.5, 1 and 5 Gy) that survived to the end of the study (14 days). In contrast, the effect persisted for 10 and 20 Gy groups, which showed suppression of RIN values <4.5 with high mortalities. Radiation doses of 20 Gy were lethal and required euthanasia by day 6. A low RIN (<2.5) at any time point was associated with 100% mortality. Combined radiation-burn injury produced significantly increased mortality such that no dually-injured animals survived beyond day 3, and no radiation dose >1 Gy resulted in survival past day 1. More modest suppression of RIN was observed in the surviving dually challenged mice, and no statistically significant changes were identified in RIN values of burn-only mice at any time point. In this study of an animal model, a proof of concept is presented for a simple and accurate method of assessing radiation dose exposure in blood which potentially predicts lethality. RIN assessment of blood-derived RNA could form the basis for a clinical decision-support tool to guide healthcare providers under the strenuous conditions of a radiation-based mass casualty event.

Further Histological and Cellular Characterization of Hidradenitis Suppurativa in 11 Patients.

Background: Hidradenitis suppurativa is a chronic inflammatory skin disease, with significant morbidity secondary to its recurrent painful and exudative lesions. Given limited research on the cytoarchitecture of hidradenitis suppurativa, this study describes the microscopic structure and cell surface markers present in hidradenitis suppurativa tissue to better understand the disease and identify potential therapeutic targets. Methods: Skin biopsies of hidradenitis suppurativa lesions from patients who underwent surgical excision (n = 11) were compared with grossly normal-appearing perilesional skin (n = 5) and normal skin biopsies from unaffected individuals (n = 4). Histopathology and epidermal thickness were assessed using hematoxylin and eosin and picrosirius red staining, and CD3, a T-cell marker, and CD31 (PECAM), a vascular endothelial cell marker, were assayed using immunofluorescence. Data were analyzed and compared using analysis of variance and Student's t test. Results: Histological examination showed that hidradenitis suppurativa samples had a significantly thicker epidermal layer than normal skin (335.23 ± 165.01 µm vs 57.24 ± 18.43 µm, P = .005), extending into and engulfing the dermis. The hidradenitis suppurativa dermis had extensive cellular infiltration and aggregation as well as disorganized collagen. Immunofluorescence analysis revealed that, at the dermal level, hidradenitis suppurativa lesions had a significantly greater quantity of CD3+ (324.29 ± 139.28 vs 14.93 ±16.32, P < .0001) and CD31+ (322.15 ± 155.46 vs 2.84 ± 5.56, P < .0001) cells/mm2 compared with normal skin samples. Conclusions: Hidradenitis suppurativa lesions have thicker epidermal layers, more dermal cellular infiltrate, and disorganized collagen fibers compared with normal skin. Furthermore, hidradenitis suppurativa dermis has a greater quantity of CD3+ and CD31+ cells than normal skin.

Reactive Oxygen Species Scavenging Potential Contributes to Hypertrophic Scar Formation.

BACKGROUND: Reactive oxygen species (ROS) can damage macromolecules if not appropriately neutralized by ROS scavengers. The balance between ROS and ROS scavengers is essential to prevent the accumulation of damage in healthy tissues. This balance is perturbed in hypertrophic scar (HTS). MATERIALS AND METHODS: Full-thickness wounds were created on the flanks of Duroc pigs at day 0 that developed into HTS (n = 4). Wounds and HTSs were biopsied weekly for 135 d. Total transcriptome microarrays were conducted with focused ROS scavenger analysis. Confirmatory quantitative reverse transcription polymerase chain reaction and immunofluorescence of ROS scavengers: superoxide dismutase 1, microsomal glutathione S-transferase 1, and peroxiredoxin 6 were performed throughout wound healing and HTS development. RESULTS: Total transcriptome microarray analysis identified over 25 ROS scavenger genes that were significantly downregulated in HTS at all time points compared with basal level controls (BL) (FDR<0.01; fold change > or <2). Ingenuity pathway analysis identified multiple ROS scavenging pathways involved in HTS (P < 0.01). Quantitative reverse transcription polymerase chain reaction of representative scavengers confirmed and expanded this finding to the initial phases of wound healing (P < 0.05, n = 4). The protein products of the genes were lower in wound and HTS tissues compared with BL. CONCLUSIONS: A balance between ROS production and scavenging must be maintained for normal wound healing, which is perturbed in wounds that heal to form HTSs. We postulate that endogenous scavengers can be administered as a prophylactic or post-treatment to rebalance ROS and attenuate symptoms of scar.

Dyspigmented hypertrophic scars: Beyond skin color.

Although pigment synthesis is well understood, relevant mechanisms of psychologically debilitating dyspigmentation in nascent tissue after cutaneous injuries are still unknown. Here, differences in genomic transcription of hyper- and hypopigmented tissue relative to uninjured skin were investigated using a red Duroc swine scar model. Transcription profiles differed based on pigmentation phenotypes with a trend of more upregulation or downregulation in hyper- or hypopigmented scars, respectively. Ingenuity Pathway Analysis of significantly modulated genes in both pigmentation phenotypes showed pathways related to redox, metabolic, and inflammatory responses were more present in hypopigmented samples, while those related to stem cell development differentiation were found mainly in hyperpigmented samples. Cell-cell and cell-extracellular matrix interactions and inflammation responses were predicted (z-score) active in hyperpigmented and inactive in hypopigmented. The proinflammatory high-mobility group box 1 pathway showed the opposite trend. Analysis of differentially regulated mutually exclusive genes showed an extensive presence of metabolic, proinflammatory, and oxidative stress pathways in hypopigmented scars, while melanin synthesis, glycosaminoglycans biosynthesis, and cell differentiation pathways were predominant in hyperpigmented scar. Several potential therapeutic gene targets have been identified.

Pigmentation Diathesis of Hypertrophic Scar: An Examination of Known Signaling Pathways to Elucidate the Molecular Pathophysiology of Injury-Related Dyschromia.

Hypertrophic scar (HTS) occurs frequently after burn injury. Treatments for some aspects of scar morbidity exist, however, dyspigmentation treatments are lacking due to limited knowledge about why scars display dyschromic phenotypes. Full thickness wounds were created on duroc pigs that healed to form dyschromic HTS. HTS biopsies and primary cell cultures were then used to study pigmentation signaling. Biopsies of areas of both pigment types were taken for analysis. At the end of the experiment, melanocyte-keratinocyte cocultures were established from areas of differential pigmentation. Heterogeneously dyspigmented scars formed with regions of hyperpigmentation and hypopigmentation. Melanocytes were present in both pigment types measured by S100ß quantitative real time-polymerase chain reaction (qRT-PCR) and immunostaining, and visualized by dendritic cell presence in primary cultures. P53 expression was not different between the two pigment types. Hyperpigmented scars had upregulated levels of proopiomelanocortin (POMC), adrenocorticotropic hormone (ACTH), α-melanocyte stimulating hormone (α-MSH), stem cell factor (SCF), and c-KIT and melanocortin 1 receptors (MC1R) compared to hypopigmented regions. Many genes involved in dyspigmentation were differentially regulated by microarray analysis including MITF, TYR, TYRP1, and DCT. MiTF expression was not different upon further exploration, but TYR, TYRP1, and DCT were upregulated in intact biopsies measured by qRT-PCR and confirmed by immunostaining. This is the first work to confirm the presence of melanocytes in hypopigmented scar using qRT-PCR and primary cell culture. An understanding of the initial steps in dyspigmentation signaling, as well as the downstream effects of these signals, will inform treatment options for patients with scars and provide insight to where pharmacotherapy may be directed.

Key Cell Functions are Modulated by Compression in an Animal Model of Hypertrophic Scar.

INTRODUCTION: The value of compression studies and applications in hypertrophic scar (HTS) treatment is often undermined due to the lack of ideal controls, patient compliance, and clear action mechanisms. OBJECTIVE: This study assesses the genome-wide compression effects on scars under well-controlled conditions. MATERIALS AND METHODS: An automated pressure delivery system (APDS) applied controlled doses of pressure to scars in a red Duroc swine HTS model. Full-thickness wounds were created by a skin grafting instrument on each animal's bilateral flanks and were observed through reepithelialization and scar development. On day 70, the APDSs were mounted on the developed scars; right flank scars received a pressure of 30 mm Hg, while left flank scars received APDSs with no pressure (sham) for 2 weeks. A genome-wide assessment of compression effect on transcription in scar specimens before (early), shortly after (mid), and long after (late) compression initiation were performed. RESULTS: Analysis of early-phase biopsies showed similar transcriptome profiles, which diverged thereafter in gene numbers and functions between compression- and sham-treated scars in the mid phase. The majority of these changes persisted in the late-phase scar samples. Canonical pathway analysis of differentially regulated genes resulted in an almost identical list of pathways during the early phase prior to compression. In the mid and late phases after compression, many of the identified pathways shifted in significance, and new pathways such as calcium signaling and cholesterol synthesis emerged. CONCLUSIONS: Compression modulates transcription and affects multiple biological functions associated with an improved scar appearance.

Matrix Metalloproteinases Are Differentially Regulated and Responsive to Compression Therapy in a Red Duroc Model of Hypertrophic Scar.

Objective: Proteins of the matrix metalloproteinases family play a vital role in extracellular matrix maintenance and basic physiological processes in tissue homeostasis. The function and activities of matrix metalloproteinases in response to compression therapies have yet to be defined. Here, a swine model of hypertrophic scar was used to profile the transcription of all known 26 matrix metalloproteinases in scars treated with a precise compression dose. Methods: Full-thickness excisional wounds were created. Wounds underwent healing and scar formation. A subset of scars underwent 2 weeks of compression therapy. Biopsy specimens were preserved, and microarrays, reverse transcription-polymerase chain reaction, Western blotting, and immunohistochemistry were performed to characterize the transcription and expression of various matrix metalloproteinase family members. Results: Microarray results showed that 13 of the known 26 matrix metalloproteinases were differentially transcribed in wounds relative to the preinjury skin. The predominant upregulation of these matrix metalloproteinases during early wound-healing stages declined gradually in later stages of wound healing. The use of compression therapy reduced this decline in 10 of the 13 differentially regulated matrix metalloproteinases. Further investigation of MMP7 using reverse transcription-polymerase chain reaction confirmed the effect of compression on transcript levels. Assessment of MMP7 at the protein level using Western blotting and immunohistochemistry was concordant. Conclusions: In a swine model of hypertrophic scar, the application of compression to hypertrophic scar attenuated a trend of decreasing levels of matrix metalloproteinases during the process of hypertrophic wound healing, including MMP7, whose enzyme regulation was confirmed at the protein level.

Disruption of Biofilms and Neutralization of Bacteria Using Hypochlorous Acid Solution: An In Vivo and In Vitro Evaluation.

OBJECTIVES: The aims of this study were to assess the effectiveness of a hypochlorous acid-based wound cleanser (Vashe Wound Solution [VWS], SteadMed Medical, Fort Worth, Texas) in disrupting methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa biofilms relative to other cleansers using an in vitro collagen biofilm model and to evaluate cleansers' cytotoxicity. The bioburden reduction of venous stasis wounds by VWS and another cleanser was evaluated. METHODS: Plates coated with collagen films incubated with active bacteria cultures to yield biofilm mimics were treated with VWS, 1% and 10% povidone-iodine (PI), 0.05% chlorhexidine wound solution (CWS), or normal saline for 3 or 10 minutes. Biofilms were then analyzed for biomass density using a crystal violet assay, quantitative cultures, and fluorescent microscopy. Cytotoxicity was measured using neutral red uptake by primary human dermal fibroblasts. Pre- and postcleansing exudates and swab samples obtained from venous stasis wounds of patients were processed and plated on a series of selective agar plates for bacteria typing and quantification. RESULTS: All agents tested significantly neutralized methicillin-resistant S aureus and P aeruginosa biofilms compared with saline control as assessed by crystal violet assay and fluorescent microscopy assays. Undiluted VWS was significantly less cytotoxic compared with 1% PI, CWS, and 10% PI (in increasing order of cytotoxicity). There was no significant difference in bacterial reduction in wounds after treatment with VWS or CWS for any type of bacteria examined using selective media. In wounds that were treated with VWS or CWS, there was a similar percentage reduction in bacterial colony-forming units from precleansing levels when plated on tryptic soy agar, MacConkey, streptococcal, and mannitol salt agar plates. Plates treated with CWS trended toward higher bacterial reduction on nonselective and gram-negative agars, whereas VWS trended toward higher bacterial reduction in Streptococcus-selective agars. CONCLUSIONS: These findings support the use of VWS in the treatment of wounds with biofilms and to reduce the bioburden of venous stasis ulcers. While VWS-treated biofilms had higher biomass than CWS- and saline-treated biofilms, most of the cellular component was not viable. Ultimately, VWS had a similar effectiveness to CWS in eliminating bacteria but with lower cytotoxicity.

Elastin Is Differentially Regulated by Pressure Therapy in a Porcine Model of Hypertrophic Scar.

Beneficial effects of pressure therapy for hypertrophic scars have been reported, but the mechanisms of action are not fully understood. This study evaluated elastin and its contribution to scar pliability. The relationship between changes in Vancouver Scar Scale (VSS) scores of pressure-treated scars and differential regulation of elastin was assessed. Hypertrophic scars were created and assessed weekly using VSS and biopsy procurement. Pressure treatment began on day 70 postinjury. Treated scars were compared with untreated shams. Treatment lasted 2 weeks, through day 84, and scars were assessed weekly through day 126. Transcript and protein levels of elastin were quantified. Pressure treatment resulted in lower VSS scores compared with sham-treated scars. Pliability (VSSP) was a key contributor to this difference. At day 70 pretreatment, VSSP = 2. Without treatment, sham-treated scars became less pliable, while pressure-treated scars became more pliable. The percentage of elastin in scars at day 70 was higher than in uninjured skin. Following treatment, the percentage of elastin increased and continued to increase through day 126. Untreated sham scars did not show a similar increase. Quantification of Verhoeff-Van Gieson staining corroborated the findings and immunofluorescence revealed the alignment of elastin fibers. Pressure treatment results in increased protein level expression of elastin compared with sham-untreated scars. These findings further characterize the extracellular matrix's response to the application of pressure as a scar treatment, which will contribute to the refinement of rehabilitation practices and ultimately improvements in functional and psychosocial outcomes for patients.

Compression therapy affects collagen type balance in hypertrophic scar.

BACKGROUND: The effects of pressure on hypertrophic scar are poorly understood. Decreased extracellular matrix deposition is hypothesized to contribute to changes observed after pressure therapy. To examine this further, collagen composition was analyzed in a model of pressure therapy in hypertrophic scar. MATERIALS AND METHODS: Hypertrophic scars created on red Duroc swine (n = 8) received pressure treatment (pressure device mounting and delivery at 30 mm Hg), sham treatment (device mounting and no delivery), or no treatment for 2 wk. Scars were assessed weekly and biopsied for histology, hydroxyproline quantification, and gene expression analysis. Transcription levels of collagen precursors COL1A2 and COL3A1 were quantified using reverse transcription-polymerase chain reaction. Masson trichrome was used for general collagen quantification, whereas immunofluorescence was used for collagen types I and III specific quantification. RESULTS: Total collagen quantification using hydroxyproline assay showed a 51.9% decrease after pressure initiation. Masson trichrome staining showed less collagen after 1 (P < 0.03) and 2 wk (P < 0.002) of pressure application compared with sham and untreated scars. Collagen 1A2 and 3A1 transcript decreased by 41.9- and 42.3-fold, respectively, compared with uninjured skin after pressure treatment, whereas a 2.3- and 1.3-fold increase was seen in untreated scars. This decrease was seen in immunofluorescence staining for collagen types I (P < 0.001) and III (P < 0.04) compared with pretreated levels. Pressure-treated scars also had lower levels of collagen I and III after pressure treatment (P < 0.05) compared with sham and untreated scars. CONCLUSIONS: These results demonstrate the modulation of collagen after pressure therapy and further characterize its role in scar formation and therapy.

Noninvasive imaging technologies for cutaneous wound assessment: A review.

The ability to phenotype wounds for the purposes of assessing severity, healing potential and treatment is an important function of evidence-based medicine. A variety of optical technologies are currently in development for noninvasive wound assessment. To varying extents, these optical technologies have the potential to supplement traditional clinical wound evaluation and research, by providing detailed information regarding skin components imperceptible to visual inspection. These assessments are achieved through quantitative optical analysis of tissue characteristics including blood flow, collagen remodeling, hemoglobin content, inflammation, temperature, vascular structure, and water content. Technologies that have, to this date, been applied to wound assessment include: near infrared imaging, thermal imaging, optical coherence tomography, orthogonal polarization spectral imaging, fluorescence imaging, laser Doppler imaging, microscopy, spatial frequency domain imaging, photoacoustic detection, and spectral/hyperspectral imaging. We present a review of the technologies in use or development for these purposes with three aims: (1) providing basic explanations of imaging technology concepts, (2) reviewing the wound imaging literature, and (3) providing insight into areas for further application and exploration. Noninvasive imaging is a promising advancement in wound assessment and all technologies require further validation.

Voltage-dependent inactivation of the plasmodial surface anion channel via a cleavable cytoplasmic component.

Erythrocytes infected with malaria parasites have increased permeability to ions and various nutrient solutes, mediated by a parasite ion channel known as the plasmodial surface anion channel (PSAC). The parasite clag3 gene family encodes PSAC activity, but there may also be additional unidentified components of this channel. Consistent with a lack of clag3 homology to genes of other ion channels, PSAC has a number of unusual functional properties. Here, we report that PSAC exhibits an unusual form of voltage-dependent inactivation. Inactivation was readily detected in the whole-cell patch-clamp configuration after steps to negative membrane potentials. The fraction of current that inactivates, its kinetics, and the rate of recovery were all voltage-dependent, though with a modest effective valence (0.7±0.1 elementary charges). These properties were not affected by solution composition or charge carrier, suggesting inactivation intrinsic to the channel protein. Intriguingly, inactivation was absent in cell-attached recordings and took several minutes to appear after obtaining the whole-cell configuration, suggesting interactions with soluble cytosolic components. Inactivation could also be largely abolished by application of intracellular, but not extracellular protease. The findings implicate inactivation via a charged cytoplasmic channel domain. This domain may be tethered to one or more soluble intracellular components under physiological conditions.

Gene expression profiling of monkeypox virus-infected cells reveals novel interfaces for host-virus interactions.

Monkeypox virus (MPV) is a zoonotic Orthopoxvirus and a potential biothreat agent that causes human disease with varying morbidity and mortality. Members of the Orthopoxvirus genus have been shown to suppress antiviral cell defenses, exploit host cell machinery, and delay infection-induced cell death. However, a comprehensive study of all host genes and virus-targeted host networks during infection is lacking. To better understand viral strategies adopted in manipulating routine host biology on global scale, we investigated the effect of MPV infection on Macaca mulatta kidney epithelial cells (MK2) using GeneChip rhesus macaque genome microarrays. Functional analysis of genes differentially expressed at 3 and 7 hours post infection showed distinctive regulation of canonical pathways and networks. While the majority of modulated histone-encoding genes exhibited sharp copy number increases, many of its transcription regulators were substantially suppressed; suggesting involvement of unknown viral factors in host histone expression. In agreement with known viral dependence on actin in motility, egress, and infection of adjacent cells, our results showed extensive regulation of genes usually involved in controlling actin expression dynamics. Similarly, a substantial ratio of genes contributing to cell cycle checkpoints exhibited concerted regulation that favors cell cycle progression in G1, S, G2 phases, but arrest cells in G2 phase and inhibits entry into mitosis. Moreover, the data showed that large number of infection-regulated genes is involved in molecular mechanisms characteristic of cancer canonical pathways. Interestingly, ten ion channels and transporters showed progressive suppression during the course of infection. Although the outcome of this unusual channel expression on cell osmotic homeostasis remains unknown, instability of cell osmotic balance and membrane potential has been implicated in intracellular pathogens egress. Our results highlight the role of histones, actin, cell cycle regulators, and ion channels in MPV infection, and propose these host functions as attractive research focal points in identifying novel drug intervention sites.

Inhibition of monkeypox virus replication by RNA interference.

The Orthopoxvirus genus of Poxviridae family is comprised of several human pathogens, including cowpox (CPXV), Vaccinia (VACV), monkeypox (MPV) and Variola (VARV) viruses. Species of this virus genus cause human diseases with various severities and outcome ranging from mild conditions to death in fulminating cases. Currently, vaccination is the only protective measure against infection with these viruses and no licensed antiviral drug therapy is available. In this study, we investigated the potential of RNA interference pathway (RNAi) as a therapeutic approach for orthopox virus infections using MPV as a model. Based on genome-wide expression studies and bioinformatic analysis, we selected 12 viral genes and targeted them by small interference RNA (siRNA). Forty-eight siRNA constructs were developed and evaluated in vitro for their ability to inhibit viral replication. Two genes, each targeted with four different siRNA constructs in one pool, were limiting to viral replication. Seven siRNA constructs from these two pools, targeting either an essential gene for viral replication (A6R) or an important gene in viral entry (E8L), inhibited viral replication in cell culture by 65-95% with no apparent cytotoxicity. Further analysis with wild-type and recombinant MPV expressing green fluorescence protein demonstrated that one of these constructs, siA6-a, was the most potent and inhibited viral replication for up to 7 days at a concentration of 10 nM. These results emphasis the essential role of A6R gene in viral replication, and demonstrate the potential of RNAi as a therapeutic approach for developing oligonucleotide-based drug therapy for MPV and other orthopox viruses.