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Experimental Dermatology Sep 2014Here, we explore the evolution and development of skin-associated adipose tissue with the goal of establishing nomenclature for this tissue. Underlying the reticular... (Review)
Review
Here, we explore the evolution and development of skin-associated adipose tissue with the goal of establishing nomenclature for this tissue. Underlying the reticular dermis, a thick layer of adipocytes exists that encases mature hair follicles in rodents and humans. The association of lipid-filled cells with the skin is found in many invertebrate and vertebrate species. Historically, this layer of adipocytes has been termed subcutaneous adipose, hypodermis and subcutis. Recent data have revealed a common precursor for dermal fibroblasts and intradermal adipocytes during development. Furthermore, the development of adipocytes in the skin is independent from that of subcutaneous adipose tissue development. Finally, the role of adipocytes has been shown to be relevant for epidermal homoeostasis during hair follicle regeneration and wound healing. Thus, we propose a refined nomenclature for the cells and adipose tissue underlying the reticular dermis as intradermal adipocytes and dermal white adipose tissue, respectively.
Topics: Adipocytes, White; Adipose Tissue, White; Animals; Dermis; Hair Follicle; Humans; Mice; Regeneration; Species Specificity; Subcutaneous Fat; Terminology as Topic; Wound Healing
PubMed: 24841073
DOI: 10.1111/exd.12450 -
Journal of Anatomy Aug 2019The structure and function of the skin relies on the complex expression pattern and organisation of extracellular matrix macromolecules, of which collagens are a... (Review)
Review
The structure and function of the skin relies on the complex expression pattern and organisation of extracellular matrix macromolecules, of which collagens are a principal component. The fibrillar collagens, types I and III, constitute over 90% of the collagen content within the skin and are the major determinants of the strength and stiffness of the tissue. However, the minor collagens also play a crucial regulatory role in a variety of processes, including cell anchorage, matrix assembly, and growth factor signalling. In this article, we review the expression patterns, key functions and involvement in disease pathogenesis of the minor collagens found in the skin. While it is clear that the minor collagens are important mediators of normal tissue function, homeostasis and repair, further insight into the molecular level structure and activity of these proteins is required for translation into clinical therapies.
Topics: Animals; Basement Membrane; Collagen; Dermis; Humans
PubMed: 31318053
DOI: 10.1111/joa.12584 -
Nan Fang Yi Ke Da Xue Xue Bao = Journal... Mar 2017As a novel population of neural crest-origin precursor cells, skin-derived precursor cells (SKPs) can be isolated from both embryonic and adult dermis. These cells have... (Review)
Review
As a novel population of neural crest-origin precursor cells, skin-derived precursor cells (SKPs) can be isolated from both embryonic and adult dermis. These cells have important values for research and potential clinical application in wound healing, organ regeneration and disease treatment for advantages in the abundance of cell sources, accessibility, potential of multipotent differentiation, and absence of ethical concerns. Here we review the developmental and anatomical origins of SKPs and their potential application in regenerative medicine. SKPs originate from the embryonic neural crest, and their sources may vary in different areas of the body. SKPs are widely found in the dermis, especially in the dermal papilla (DP), which was known as a niche of SKPs. The multipotent SKPs can used for autologous transplantation and are of vital importance in tissue repair.
Topics: Cell Differentiation; Cells, Cultured; Dermis; Humans; Neural Crest; Skin; Stem Cells; Wound Healing
PubMed: 28377365
DOI: 10.3969/j.issn.1673-4254.2017.03.26 -
Dermatologic Clinics Oct 2016The aim of the current review is to provide an overview of the use of reflectance confocal microscopy to detect early skin aging signs. This new imaging tool holds the... (Review)
Review
The aim of the current review is to provide an overview of the use of reflectance confocal microscopy to detect early skin aging signs. This new imaging tool holds the promise to morphologically explore the epidermis and upper dermis at nearly histologic resolution and over time. The main confocal findings of aged skin include the presence of irregular honeycombed pattern, linear skin furrows, mottled pigmentation, and distinct collagen types (coarse and huddled).
Topics: Dermis; Early Diagnosis; Epidermis; Humans; Intravital Microscopy; Microscopy, Confocal; Skin Aging; Skin Pigmentation
PubMed: 27692457
DOI: 10.1016/j.det.2016.05.014 -
Cellular Immunology Apr 2020Various immune cells are present in the skin and modulate the cutaneous immune response. In order to capture such dynamic phenomena, intravital imaging is an important... (Review)
Review
Various immune cells are present in the skin and modulate the cutaneous immune response. In order to capture such dynamic phenomena, intravital imaging is an important technique and there is a possibility to provide substantial information that is not available using conventional histological analysis. Multiphoton microscope enable direct, three-dimensional, minimally invasive imaging of biological samples with high spatiotemporal resolution, and now become the main method for intravital imaging studies. Here, we will introduce the latest knowledge obtained by intravital imaging of the skin.
Topics: Animals; Dermis; Epidermis; Humans; Intravital Microscopy; Keratinocytes; Mice; Mice, Transgenic; Microscopy, Fluorescence, Multiphoton; Skin
PubMed: 29807622
DOI: 10.1016/j.cellimm.2018.05.006 -
Advances in Experimental Medicine and... 2020Maintaining integrity of the skin and its appendages still preserves its top-ranking in priorities of survival for the modern human as it probably once did for the... (Review)
Review
Maintaining integrity of the skin and its appendages still preserves its top-ranking in priorities of survival for the modern human as it probably once did for the ancient individual, -not only- because it is the primary barrier to external assaults, but also because of social and psychological impact of healthy skin during their life-span. Healing wounds in order to shield off the internal organs from infections and damage, restoring its ability to adapt to various environmental stimuli, and slowing-down and reversing aging of the skin in the quest for an everlasting youth can be named as a few of the main drivers behind the multi-million investments dedicated to the advancement of our understanding of skin's physiology. Over the years, these tremendous efforts culminated in the breakthrough discovery of skin stem cells the regenerative capacity of which accounted for the resilience of the skin through their unique capacity as a special cell type that can both self-renew and differentiate into various lineages. In this review, first we summarize the current knowledge on this amazing organ both at a structural and functional level. Next, we provide a comprehensive -in depth- discussion on epidermal as well as dermal stem cells in terms of the key regulatory pathways as well as the main genetic factors that have been implicated in the orchestration of the skin stem cell biology in regards to the shifts between quiescence and entry into distinct differentiation programs.
Topics: Animals; Dermis; Epidermis; Humans; Skin; Skin Physiological Phenomena; Stem Cells
PubMed: 31953808
DOI: 10.1007/5584_2019_442 -
ACS Biomaterials Science & Engineering May 2023Pathological hair loss (also known as alopecia) and shortage of hair follicle (HF) donors have posed an urgent requirement for HF regeneration. With the revelation of... (Review)
Review
Pathological hair loss (also known as alopecia) and shortage of hair follicle (HF) donors have posed an urgent requirement for HF regeneration. With the revelation of mechanisms in tissue engineering, the proliferation of HFs in vitro has achieved more promising trust for the treatments of alopecia and other skin impairments. Theoretically, HF organoids have great potential to develop into native HFs and attachments such as sweat glands after transplantation. However, since the rich extracellular matrix (ECM) deficiency, the induction characteristics of skin-derived cells gradually fade away along with their trichogenic capacity after continuous cell passaging in vitro. Therefore, ECM-mimicking support is an essential prelude before HF transplantation is implemented. This review summarizes the status of providing various epidermal and dermal cells with a three-dimensional (3D) scaffold to support the cell homeostasis and better mimic in vivo environments for the sake of HF regeneration. HF-relevant cells including dermal papilla cells (DPCs), hair follicle stem cells (HFSCs), and mesenchymal stem cells (MSCs) are able to be induced to form HF organoids in the vitro culture system. The niche microenvironment simulated by different forms of biomaterial scaffold can offer the cells a network of ordered growth environment to alleviate inductivity loss and promote the expression of functional proteins. The scaffolds often play the role of ECM substrates and bring about epithelial-mesenchymal interaction (EMI) through coculture to ensure the functional preservation of HF cells during in vitro passage. Functional HF organoids can be formed either before or after transplantation into the dermis layer. Here, we review and emphasize the importance of 3D culture in HF regeneration in vitro. Finally, the latest progress in treatment trials and critical analysis of the properties and benefits of different emerging biomaterials for HF regeneration along with the main challenges and prospects of HF regenerative approaches are discussed.
Topics: Humans; Hair Follicle; Dermis; Regeneration; Alopecia; Tissue Engineering
PubMed: 37036820
DOI: 10.1021/acsbiomaterials.3c00028 -
International Journal of Molecular... Jul 2021We studied CD34+ stromal cells/telocytes (CD34+SCs/TCs) in pathologic skin, after briefly examining them in normal conditions. We confirm previous studies by other... (Review)
Review
We studied CD34+ stromal cells/telocytes (CD34+SCs/TCs) in pathologic skin, after briefly examining them in normal conditions. We confirm previous studies by other authors in the normal dermis regarding CD34+SC/TC characteristics and distribution around vessels, nerves and cutaneous annexes, highlighting their practical absence in the papillary dermis and presence in the bulge region of perifollicular groups of very small CD34+ stromal cells. In non-tumoral skin pathology, we studied examples of the principal histologic patterns in which CD34+SCs/TCs have (1) a fundamental pathophysiological role, including (a) fibrosing/sclerosing diseases, such as systemic sclerosis, with loss of CD34+SCs/TCs and presence of stromal cells co-expressing CD34 and αSMA, and (b) metabolic degenerative processes, including basophilic degeneration of collagen, with stromal cells/telocytes in close association with degenerative fibrils, and cutaneous myxoid cysts with spindle-shaped, stellate and bulky vacuolated CD34+ stromal cells, and (2) a secondary reactive role, encompassing dermatitis-e.g., interface (erythema multiforme), acantholytic (pemphigus, Hailey-Hailey disease), lichenoid (lichen planus), subepidermal vesicular (bullous pemphigoid), psoriasiform (psoriasis), granulomatous (granuloma annulare)-vasculitis (leukocytoclastic and lymphocytic vasculitis), folliculitis, perifolliculitis and inflammation of the sweat and sebaceous glands (perifolliculitis and rosacea) and infectious dermatitis (verruca vulgaris). In skin tumor and tumor-like conditions, we studied examples of those in which CD34+ stromal cells are (1) the neoplastic component (dermatofibrosarcoma protuberans, sclerotic fibroma and solitary fibrous tumor), (2) a neoplastic component with varying presentation (fibroepithelial polyp and superficial myxofibrosarcoma) and (3) a reactive component in other tumor/tumor-like cell lines, such as those deriving from vessel periendothelial cells (myopericytoma), epithelial cells (trichoepithelioma, nevus sebaceous of Jadassohn and seborrheic keratosis), Merkel cells (Merkel cell carcinoma), melanocytes (dermal melanocytic nevi) and Schwann cells (neurofibroma and granular cell tumor).
Topics: Animals; Antigens, CD34; Dermatitis; Dermis; Humans; Neoplasm Proteins; Skin Neoplasms; Telocytes
PubMed: 34298962
DOI: 10.3390/ijms22147342 -
The Journal of Investigative Dermatology Jan 2022This review focuses on recent advances in understanding the mechanisms involved in itch signaling in the skin and how these new findings fit into the wider picture of... (Review)
Review
This review focuses on recent advances in understanding the mechanisms involved in itch signaling in the skin and how these new findings fit into the wider picture of the expression of itch mediators and their receptors in the dermal layer. Because at present studies mostly concentrate on single cellular compartments (e.g., neural alone), we suggest that they may miss important interactions with other compartments. Therefore, to fully appreciate pruritus, we propose that studies should consider (e.g., using transcriptomic information) signal transmission within the entire neuro‒immune‒stromal triad.
Topics: Animals; Cell Communication; Dermis; Humans; Neuroimmunomodulation; Pruritus; Signal Transduction; Single-Cell Analysis; Stromal Cells; Transcriptome
PubMed: 34662564
DOI: 10.1016/j.jid.2021.08.443 -
Science (New York, N.Y.) Nov 2014The skin is our largest sensory organ, transmitting pain, temperature, itch, and touch information to the central nervous system. Touch sensations are conveyed by... (Review)
Review
The skin is our largest sensory organ, transmitting pain, temperature, itch, and touch information to the central nervous system. Touch sensations are conveyed by distinct combinations of mechanosensory end organs and the low-threshold mechanoreceptors (LTMRs) that innervate them. Here we explore the various structures underlying the diverse functions of cutaneous LTMR end organs. Beyond anchoring of LTMRs to the surrounding dermis and epidermis, recent evidence suggests that the non-neuronal components of end organs play an active role in signaling to LTMRs and may physically gate force-sensitive channels in these receptors. Combined with LTMR intrinsic properties, the balance of these factors comprises the response properties of mechanosensory neurons and, thus, the neural encoding of touch.
Topics: Animals; Dermis; Epidermis; Hair; Hair Follicle; Humans; Mechanoreceptors; Mechanotransduction, Cellular; Merkel Cells; Neurons; Pacinian Corpuscles; Touch
PubMed: 25414303
DOI: 10.1126/science.1254229