title: IL-11, IL-1α, IL-6, and TNF-α are induced by solar radiation in vitro and may be involved in facial subcutaneous fat loss in vivo.
abstract: BACKGROUND
  The loss of subcutaneous (sc) fat is associated with aging. Inflammatory cytokines, such as interleukin-1 α (IL-1α), interleukin-11 (IL-11) and tumor necrosis factor-α (TNF-α), are known to inhibit the differentiation of preadipocytes.
  
  
  OBJECTIVE
  This study investigated the potential role of inflammatory cytokines in solar-radiation-induced facial fat loss.
  
  
  METHODS
  Cultured fibroblasts, keratinocytes, and skin equivalents were exposed to various doses of radiation from a solar simulator. Inflammatory cytokines' mRNA production and protein secretion were examined by qRT-PCR and ELISA, respectively. In some experiments, epidermal-dermal equivalents were pretreated topically with a broad-spectrum sunscreen prior to solar simulated radiation (SSR). Human facial preadipocytes treated with recombinant IL-11 or with conditioned media from solar-irradiated equivalents were evaluated for the level of adipocyte differentiation by image analyses, Oil red O staining, and the expression of adipocyte differentiation markers.
  
  
  RESULTS
  IL-11, IL-1α, IL-6, and TNF-α protein secretion were induced from epidermal-dermal equivalents by exposure to SSR. A sunscreen prevented SSR-induced inflammatory cytokines production from such equivalents. Exposure of facial preadipocytes to conditioned medium from solar-irradiated epidermal-dermal equivalents inhibited their differentiation into mature adipocytes. Consequently, conditioned medium from sunscreen-pretreated, solar-irradiated equivalents did not inhibit differentiation of preadipocytes. A cocktail of neutralizing antibodies to IL-11, IL-1α, IL-6 and TNF-α significantly reduced the SSR-induced inhibition of preadipocyte differentiation.
  
  
  CONCLUSIONS
  These results support the hypothesis that SSR-induced inflammatory cytokine may be involved in the photoaging-induced loss of facial subcutaneous fat. Inhibition of this process, e.g. by sunscreens, might slow or prevent photoaging-induced changes in facial contouring.
authors: The Johnson & Johnson Skin Research Center, Consumer & Personal Products Worldwide, A Division of Johnson & Johnson Family of Consumer Companies, Inc., 199 Grandview Road, Skillman, NJ 08558, USA. whli@its.jnj.com
authors: Wen-Hwa
authors: WH
authors: Li
authors: Apostolos
authors: A
authors: Pappas
authors: Li
authors: L
authors: Zhang
authors: Eduardo
authors: E
authors: Ruvolo
authors: Druie
authors: D
authors: Cavender
mesh_terms: D017667:Adipocytes / Q000276:immunology / Q000528:radiation effects; D050156:Adipogenesis / Q000528:radiation effects; D057134:Antibodies, Neutralizing / Q000494:pharmacology; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000378:metabolism; D005347:Fibroblasts / Q000276:immunology / Q000528:radiation effects; D006801:Humans; D018836:Inflammation Mediators / Q000037:antagonists & inhibitors / Q000378:metabolism*; D017370:Interleukin-11 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D053582:Interleukin-1alpha / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism*; D015603:Keratinocytes / Q000276:immunology / Q000528:radiation effects; D012333:RNA, Messenger / Q000378:metabolism; D012867:Skin / Q000187:drug effects / Q000276:immunology / Q000473:pathology / Q000528:radiation effects*; D015595:Skin Aging / Q000187:drug effects / Q000528:radiation effects*; D050151:Subcutaneous Fat / Q000187:drug effects / Q000276:immunology / Q000473:pathology / Q000528:radiation effects*; D013473:Sunscreening Agents / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D014466:Ultraviolet Rays; D015854:Up-Regulation; D000093242:Interleukin-6 Inhibitors
chemical_list: D057134:Antibodies, Neutralizing; D017077:Culture Media, Conditioned; D018836:Inflammation Mediators; D017370:Interleukin-11; D053582:Interleukin-1alpha; D015850:Interleukin-6; D012333:RNA, Messenger; D013473:Sunscreening Agents; D014409:Tumor Necrosis Factor-alpha; D000093242:Interleukin-6 Inhibitors; C508611:IL11 protein, human; C508600:IL6 protein, human