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Angiogenesis Apr 2014Lymphatic vessels transport fluid, antigens, and immune cells to the lymph nodes to orchestrate adaptive immunity and maintain peripheral tolerance. Lymphangiogenesis...
Lymphatic vessels transport fluid, antigens, and immune cells to the lymph nodes to orchestrate adaptive immunity and maintain peripheral tolerance. Lymphangiogenesis has been associated with inflammation, cancer metastasis, autoimmunity, tolerance and transplant rejection, and thus, targeted lymphatic ablation is a potential therapeutic strategy for treating or preventing such events. Here we define conditions that lead to specific and local closure of the lymphatic vasculature using photodynamic therapy (PDT). Lymphatic-specific PDT was performed by irradiation of the photosensitizer verteporfin that effectively accumulates within collecting lymphatic vessels after local intradermal injection. We found that anti-lymphatic PDT induced necrosis of endothelial cells and pericytes, which preceded the functional occlusion of lymphatic collectors. This was specific to lymphatic vessels at low verteporfin dose, while higher doses also affected local blood vessels. In contrast, light dose (fluence) did not affect blood vessel perfusion, but did affect regeneration time of occluded lymphatic vessels. Lymphatic vessels eventually regenerated by recanalization of blocked collectors, with a characteristic hyperplasia of peri-lymphatic smooth muscle cells. The restoration of lymphatic function occurred with minimal remodeling of non-lymphatic tissue. Thus, anti-lymphatic PDT allows control of lymphatic ablation and regeneration by alteration of light fluence and photosensitizer dose.
Topics: Ablation Techniques; Animals; Cell Death; Dermis; Dose-Response Relationship, Drug; Ear; Endothelial Cells; Kinetics; Light; Lymphatic Vessels; Mice; Photochemotherapy; Photosensitizing Agents; Regeneration
PubMed: 23892627
DOI: 10.1007/s10456-013-9365-6 -
PloS One 2019We developed a novel skin regeneration therapy combining nevus tissue inactivated by high hydrostatic pressure (HHP) in the reconstruction of the dermis with a cultured...
We developed a novel skin regeneration therapy combining nevus tissue inactivated by high hydrostatic pressure (HHP) in the reconstruction of the dermis with a cultured epidermal autograft (CEA). The issue with this treatment is the unstable survival of CEA on the inactivated dermis. In this study, we applied collagen/gelatin sponge (CGS), which can sustain the release of basic fibroblast growth factor (bFGF), to the inactivated skin in order to accelerate angiogenesis. Murine skin grafts from C57BL6J/Jcl mice (8 mm in diameter) were prepared, inactivated by HHP and cryopreserved. One month later, the grafts were transplanted subcutaneously onto the back of other mice and covered by CGS impregnated with saline or bFGF. Grafts were harvested after one, two and eight weeks, at which point the engraftment was evaluated through the histology and angiogenesis-related gene expressions were determined by real-time polymerase chain reaction. Histological sections showed that the dermal cellular density and newly formed capillaries in the bFGF group were significantly higher than in the control group. The relative expression of FGF-2, PDGF-A and VEGF-A genes in the bFGF group was significantly higher than in the control group at Week 1. This study suggested that the angiogenesis into grafts was accelerated, which might improve the engraftment of inactivated dermis in combination with the sustained release of bFGF by CGSs.
Topics: Animals; Capillaries; Collagen; Delayed-Action Preparations; Dermis; Fibroblast Growth Factor 2; Gelatin; Hydrostatic Pressure; Male; Mice; Mice, Inbred C57BL; Neovascularization, Physiologic; Regeneration; Skin Transplantation; Tissue Scaffolds
PubMed: 30789932
DOI: 10.1371/journal.pone.0208658 -
Advanced Healthcare Materials Jul 2017Several skin equivalent models have been developed to investigate in vitro the re-epithelialization process occurring during wound healing. Although these models...
Several skin equivalent models have been developed to investigate in vitro the re-epithelialization process occurring during wound healing. Although these models recapitulate closure dynamics of epithelial cells, they fail to capture how a wounded connective tissue rebuilds its 3D architecture until the evolution in a scar. Here, the in vitro tissue repair dynamics of a connective tissue is replicated by using a 3D human dermis equivalent (3D-HDE) model composed of fibroblasts embedded in their own extracellular matrix (ECM). After inducing a physical damage, 3D-HDE undergoes a series of cellular and extracellular events quite similar to those occurring in the native dermis. In particular, fibroblasts differentiation toward myofibroblasts phenotype and neosynthesis of hyaluronic acid, fibronectin, and collagen during the repair process are assessed. Moreover, tissue reorganization after physical damage is investigated by measuring the diameter of bundles and the orientation of fibers of the newly formed ECM network. Finally, the ultimate formation of a scar-like tissue as physiological consequence of the repair and closure process is demonstrated. Taking together, the results highlight that the presence of cell-assembled and responsive stromal components enables quantitative and qualitative in vitro evaluation of the processes involved in scarring during wound healing.
Topics: Dermis; Extracellular Matrix; Female; Humans; Male; Models, Biological; Myofibroblasts; Wound Healing
PubMed: 28407433
DOI: 10.1002/adhm.201601422 -
Physics in Medicine and Biology Jan 2001The weak absorption of shortwave infrared light by skin tissues between 700 and 1500 nm offers an important window for diagnosis by optical means. The strong scattering...
The weak absorption of shortwave infrared light by skin tissues between 700 and 1500 nm offers an important window for diagnosis by optical means. The strong scattering of shortwave infrared light by the skin, however, presents a challenge to the modelling of light propagation through the skin and the understanding of skin optics. We have measured the collimated and diffuse transmittance and diffuse reflectance of porcine skin dermis samples within 30 h post-mortem. Monte Carlo simulations have been performed to inversely determine the absorption coefficient, scattering coefficient and anisotropy factor of the dermis samples in the spectral range from 900 to 1500 nm. We further analyse the sensitivity of the values of the parameters to the experimental errors and inverse calculation procedures. The state of the cellular integrity of the skin samples following optical measurements was verified using transmission electron microscopy. These results were correlated to study post-mortem effects on the in vitro optical properties of porcine dermis. We concluded that for samples stored within crushed ice for up to 30 h post-mortem the wavelength dependence of optical properties of the dermis remains unchanged while the values of the parameters vary moderately due to modification of the water content of the tissue.
Topics: Animals; Anisotropy; Calibration; Dermis; Light; Microscopy, Electron; Models, Statistical; Models, Theoretical; Monte Carlo Method; Scattering, Radiation; Sensitivity and Specificity; Swine; Time Factors; Water
PubMed: 11197670
DOI: 10.1088/0031-9155/46/1/312 -
Development (Cambridge, England) Nov 2000Somites are transient mesodermal structures giving rise to all skeletal muscles of the body, the axial skeleton and the dermis of the back. Somites arise from successive...
Somites are transient mesodermal structures giving rise to all skeletal muscles of the body, the axial skeleton and the dermis of the back. Somites arise from successive segmentation of the presomitic mesoderm (PSM). They appear first as epithelial spheres that rapidly differentiate into a ventral mesenchyme, the sclerotome, and a dorsal epithelial dermomyotome. The sclerotome gives rise to vertebrae and ribs while the dermomyotome is the source of all skeletal muscles and the dorsal dermis. Quail-chick fate mapping and diI-labeling experiments have demonstrated that the epithelial somite can be further subdivided into a medial and a lateral moiety. These two subdomains are derived from different regions of the primitive streak and give rise to different sets of muscles. The lateral somitic cells migrate to form the musculature of the limbs and body wall, known as the hypaxial muscles, while the medial somite gives rise to the vertebrae and the associated epaxial muscles. The respective contribution of the medial and lateral somitic compartments to the other somitic derivatives, namely the dermis and the ribs has not been addressed and therefore remains unknown. We have created quail-chick chimeras of either the medial or lateral part of the PSM to examine the origin of the dorsal dermis and the ribs. We demonstrate that the whole dorsal dermis and the proximal ribs exclusively originates from the medial somitic compartment, whereas the distal ribs derive from the lateral compartment.
Topics: Animals; Body Patterning; Cell Differentiation; Chick Embryo; Chimera; Dermis; Embryo, Nonmammalian; Mesoderm; Morphogenesis; Quail; Ribs
PubMed: 11023864
DOI: 10.1242/dev.127.21.4611 -
Skin Research and Technology : Official... May 2019Skin aging is a complex biological process mixing intrinsic and extrinsic factors, such as sun exposure. At the molecular level, skin aging affects in particular the...
BACKGROUND
Skin aging is a complex biological process mixing intrinsic and extrinsic factors, such as sun exposure. At the molecular level, skin aging affects in particular the extracellular matrix proteins.
MATERIALS AND METHODS
Using Raman imaging, which is a nondestructive approach appropriate for studying biological samples, we analyzed how aging modifies the matrix proteins of the papillary and reticular dermis. Biopsies from the buttock and dorsal forearm of volunteers younger than 30 and older than 60 were analyzed in order to identify chronological and photoaging processes. Analyses were performed on skin section, and Raman spectra were acquired separately on the different dermal layers.
RESULTS
We observed differences in dermal matrix structure and hydration state with skin aging. Chronological aging alters in particular the collagen of the papillary dermis, while photoaging causes a decrease in collagen stability by altering proline and hydroxyproline residues in the reticular dermis. Moreover, chronological aging alters glycosaminoglycan content in both dermal compartments.
CONCLUSION
Alterations of the papillary and reticular dermal matrix structures during photo- and chronological aging were clearly depicted by Raman spectroscopy.
Topics: Adult; Aging; Biopsy; Buttocks; Dermis; Female; Forearm; Glycosaminoglycans; Humans; Middle Aged; Skin Aging; Spectrum Analysis, Raman; Young Adult
PubMed: 30402919
DOI: 10.1111/srt.12643 -
Journal of Drugs in Dermatology : JDD Apr 2016Although manufacturers' instructions for use of dermal fillers ordinarily direct injection in the superficial, mid or deep dermis, or, in some cases, the hypodermis...
Although manufacturers' instructions for use of dermal fillers ordinarily direct injection in the superficial, mid or deep dermis, or, in some cases, the hypodermis (subcutis), the precise depth of injection may not always be for injectors. In this article, investigators report findings gathered from histopathology, ultrasound, "live" one on one training injections, as well as application of a mathematical formula for depth calculation of the various layers within the dermis. Areas of particular interest are the superficial reticular dermis and the mid dermis. Following the depth measurements detailed by Della Volpe et al in 2012, investigators compare and contrast their own depth findings of the various layers, arriving at the conclusion that the depth of the dermis is not as deep as had been previously assumed. The investigators also develop an argument for the appropriate angles of injection for placement of dermal filler into the various layers, demonstrating that the heretofore widely used angles of 30˚ and 45˚ are far more acute than required.
Topics: Cosmetic Techniques; Dermal Fillers; Dermis; Humans; Injections, Subcutaneous; Models, Theoretical; Needles; Ultrasonography
PubMed: 27050704
DOI: No ID Found -
Scientific Reports Apr 2017The papillary dermis of human skin is responsible for its biomechanical properties and for supply of epidermis with chemicals. Dermis is mainly composed of structural...
The papillary dermis of human skin is responsible for its biomechanical properties and for supply of epidermis with chemicals. Dermis is mainly composed of structural protein molecules, including collagen and elastin, and contains blood capillaries. Connective tissue diseases, as well as cardiovascular complications have manifestations on the molecular level in the papillary dermis (e.g. alteration of collagen I and III content) and in the capillary structure. In this paper we assessed the molecular structure of internal and external regions of skin capillaries using two-photon fluorescence lifetime imaging (FLIM) of endogenous compounds. It was shown that the capillaries are characterized by a fast fluorescence decay, which is originated from red blood cells and blood plasma. Using the second harmonic generation signal, FLIM segmentation was performed, which provided for spatial localization and fluorescence decay parameters distribution of collagen I and elastin in the dermal papillae. It was demonstrated that the lifetime distribution was different for the inner area of dermal papillae around the capillary loop that was suggested to be due to collagen III. Hence, we propose a generalized approach to two-photon imaging of the papillary dermis components, which extends the capabilities of this technique in skin diagnosis.
Topics: Capillaries; Collagen Type I; Collagen Type III; Dermis; Elastin; Healthy Volunteers; Humans; Optical Imaging
PubMed: 28446767
DOI: 10.1038/s41598-017-01238-w -
Advanced Healthcare Materials May 2018A novel, pure, synthetic material is presented that promotes the repair of full-thickness skin wounds. The active component is tropoelastin and leverages its ability to...
A novel, pure, synthetic material is presented that promotes the repair of full-thickness skin wounds. The active component is tropoelastin and leverages its ability to promote new blood vessel formation and its cell recruiting properties to accelerate wound repair. Key to the technology is the use of a novel heat-based, stabilized form of human tropoelastin which allows for tunable resorption. This implantable material contributes a tailored insert that can be shaped to the wound bed, where it hydrates to form a conformable protein hydrogel. Significant benefits in the extent of wound healing, dermal repair, and regeneration of mature epithelium in healthy pigs are demonstrated. The implant is compatible with initial co-treatment with full- and split-thickness skin grafts. The implant's superiority to sterile bandaging, commercial hydrogel and dermal regeneration template products is shown. On this basis, a new concept for a prefabricated tissue repair material for point-of-care treatment of open wounds is provided.
Topics: Absorbable Implants; Animals; Autografts; Blood Vessels; Dermis; Humans; Hydrogel, Polyethylene Glycol Dimethacrylate; Mice; Swine; Tissue Scaffolds; Tropoelastin; Wound Healing
PubMed: 29450975
DOI: 10.1002/adhm.201701206 -
Tissue & Cell Aug 2021The role of dermal white adipose tissue (dWAT) has emerged in the biomedical science as an ancillary fat district in the derma without a defined and distinct function... (Review)
Review
The role of dermal white adipose tissue (dWAT) has emerged in the biomedical science as an ancillary fat district in the derma without a defined and distinct function respect to the subcutaneous adipose tissue (sWAT). Despite some evidence describing dWAT as an immune-competent compartment, particularly engaged in wound repair, very few reports dealing with dWAT has elucidated its major modulatory role within the skin biology. Whereas an increasing bulk of evidence allows researcher to describe the main activity of sWAT, in humans dWAT is not properly a separated fat compartment and therefore scarcely considered in the scientific debate. Due to its strategic position between epidermis and sWAT, dermal fat might play a much more intriguing role than expected. This review tries to shed light on this issue, by expanding the debate about a possible role of dWAT in skin physiology.
Topics: Adipogenesis; Animals; Dermis; Humans; Lipid Metabolism; Subcutaneous Fat
PubMed: 34171520
DOI: 10.1016/j.tice.2021.101583