ABSTRACT
BACKGROUND: N-palmitoylethanolamine (PEA) and organic osmolytes are endogenous components of the human epidermis and are generated from phospholipids in the stratum granulosum. PEA has been shown to exert potent antioxidant and anti-inflammatory activities. The endogenous organic osmolytes such as betaine and sarcosine control skin humidity, but have also been shown to inhibit ultraviolet (UV) light-induced oxidative stress in keratinocytes. OBJECTIVES: To investigate the effect of a PEA- and organic osmolyte-containing topical product (Physiogel AI) on the development of UV light-induced erythema, thymine dimer formation and p53 tumor suppressor gene activation, as well as intercellular adhesion molecule 1 (ICAM-1) and Ki67 expression in normal human skin. METHODS: The UV-induced erythema was measured by a spectrofluorometric method. Thymine dimers, p53, ICAM-1 and Ki67 were detected in skin biopsies using immunohistochemistry. RESULTS: Physiogel AI cream significantly inhibited the development of UV light-induced erythema and thymine dimer formation in normal human skin, but did not alter the number of Ki67+ proliferating keratinocytes and the expression of p53 and ICAM-1. CONCLUSIONS: Our results suggest that PEA and organic osmolytes might represent a new generation of compounds which suppress UV-induced photodamage.
Subject(s)
Betaine/therapeutic use , DNA Damage , Erythema/prevention & control , Palmitic Acids/therapeutic use , Radiodermatitis/prevention & control , Sarcosine/therapeutic use , Skin/drug effects , Sunscreening Agents/therapeutic use , Administration, Cutaneous , Adult , Amides , Betaine/administration & dosage , Betaine/chemistry , Chemistry, Pharmaceutical , DNA/drug effects , DNA/radiation effects , Dose-Response Relationship, Radiation , Drug Combinations , Endocannabinoids , Erythema/etiology , Erythema/metabolism , Ethanolamines , Gels , Humans , Palmitic Acids/administration & dosage , Palmitic Acids/chemistry , Pyrimidine Dimers/metabolism , Radiodermatitis/etiology , Radiodermatitis/metabolism , Sarcosine/administration & dosage , Sarcosine/chemistry , Skin/metabolism , Skin/radiation effects , Sunscreening Agents/administration & dosage , Sunscreening Agents/chemistry , Treatment Outcome , Ultraviolet Rays/adverse effectsABSTRACT
To further elucidate mechanisms involved in mast cell accumulation at sites of cutaneous inflammation, we have studied the ability of human leukemic mast cells (HMC-1 cells) to express functionally active IL-8 receptors. Expression of mRNA for both types of IL-8 receptors (CXCR1 and CXCR2) was demonstrated by PCR and of both proteins by flow cytometry. Binding and competition studies with 125I-labeled IL-8 and its homologue melanoma growth stimulating activity (125I-labeled MGSA) revealed two specific binding sites for IL-8, K1 = 1.1 x 10(11) M(-1) and K2 = 5 x 10(7) M(-1); and for MGSA, K1 = 2.8 x 10(10) M(-1) and K2 = 5 x 10(7) M(-1). This finding was supported by a dose-dependent rise of cytosolic free calcium concentration ([Ca2+]i) induced by both chemokines and to a lesser extent by the homologue neutrophil-activating peptide-2 (NAP-2). A significant migratory response of human leukemic mast cells (HMC-1) was observed with all three chemokines at a range from 10(-8) M to 10(-9) M. Moreover, the formation of cellular F-actin was induced in a rapid, dose-dependent fashion, with a maximally 1.7-fold increase at 10(-7) M. Using postembedding immunoelectron microscopy, we could show the expression of CXCRI on the cytoplasmatic membrane of isolated human skin mast cells whereas CXCR2 was located in mast cell-specific granules. These findings demonstrate for the first time the functional expression of both types of IL-8 receptors on human mast cells, suggesting a role for their ligands during mast cell activation and recruitment.
Subject(s)
Antigens, CD/biosynthesis , Chemokines, CXC , Intercellular Signaling Peptides and Proteins , Interleukin-8/metabolism , Mast Cells/metabolism , Receptors, Chemokine/biosynthesis , Receptors, Interleukin/biosynthesis , Actins/metabolism , Antigens, CD/genetics , Antigens, CD/physiology , Antigens, CD/ultrastructure , Binding, Competitive , Calcium/metabolism , Cell Movement/drug effects , Chemokine CXCL1 , Chemotactic Factors/metabolism , Chemotactic Factors/pharmacology , Flow Cytometry , Growth Substances/metabolism , Growth Substances/pharmacology , HL-60 Cells , Humans , Interleukin-8/pharmacology , Iodine Radioisotopes , Mast Cells/physiology , Mast Cells/ultrastructure , Peptides/pharmacology , Polymerase Chain Reaction , Protein Binding , RNA, Messenger/biosynthesis , Receptors, Chemokine/genetics , Receptors, Chemokine/physiology , Receptors, Interleukin/genetics , Receptors, Interleukin/physiology , Receptors, Interleukin/ultrastructure , Receptors, Interleukin-8A , Receptors, Interleukin-8B , Skin/metabolism , Skin/ultrastructure , Tumor Cells, Cultured , beta-ThromboglobulinABSTRACT
It is generally accepted that keratinocyte migration plays a critical role in the process of wound healing. A study was therefore made of the migratory response of freshly separated and cultured human keratinocytes to factors with chemotactic properties for a variety of cells. Interleukin-1 alpha (IL-1 alpha), interferon-gamma (IFN-gamma), interleukin-8 (IL-8), and tumour necrosis factor alpha (TNF-alpha) were tested for their chemotactic effectiveness in a modified Boyden chamber assay. IFN-gamma, IL-1 alpha and IL-8 were demonstrated to serve as chemoattractants for freshly separated keratinocytes. For cultured cells, however, only IFN-gamma was found to display chemotactic properties. The findings demonstrate that there is significant difference between the chemotactic behaviour of freshly separated and cultured cells.
Subject(s)
Chemotaxis , Cytokines/pharmacology , Keratinocytes/physiology , Cells, Cultured , Humans , Interferon-gamma/pharmacology , Interleukin-1/pharmacology , Interleukin-8/pharmacology , Keratinocytes/drug effects , Time Factors , Tumor Necrosis Factor-alpha/pharmacologyABSTRACT
Unscheduled DNA synthesis, photoreplication repair capacity, and photoreactivating enzyme levels were examined in cells of individuals of a family with one case of XP and otherwise clinically normal parents. The patient's parents were first cousins. The activity of three paths of DNA repair was depressed in the XP cells. The clinically normal parents showed normal levels of unscheduled DNA synthesis as well as postreplication repair, however their photoreactivating enzyme level was as low as 30% of normal levels.
