INVESTIGATIVE REPORT
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ActaDV ActaDV Advances in dermatology and venereology Acta Dermato-Venereologica
Effects of Extracellular Calcium and 1,25 dihydroxyvitamin D3 on Sebaceous Gland Cells In vitro and In vivo *
Christos C . ZOUBOULIS 1 , Holger SELTMANN 1 , M . Badawy ABDEL-NASER 1 , Amir M . HOSSINI 1 , Gopinathan K . MENON 2 and Raj KUBBA 3
1
Departments of Dermatology , Venereology , Allergology and Immunology , Dessau Medical Center , Dessau , Germany , 2 ASI Corporation , Bridgewater , USA , and 3 Delhi Dermatology Group , Kubba Clinic , New Delhi , Delhi , India
Calcium and 1,25 dihydroxyvitamin D3 ( 1,25 ( OH ) 2D3 ) are promoters of epithelial cell functions ; however their effects on sebaceous glands are unknown . In this study , morphology , ultrastructure , cell numbers , lipid synthesis and apoptosis of SZ95 sebocytes were assessed in vitro under different concentrations of extracellular calcium with or without 1,25 ( OH ) 2D3 . Moreover , serum calcium and 1,25 ( OH ) 2D3 levels were assessed in acne and non-acne patients ( controls ). Under conditions of low extracellular calcium , lipogenesis and cell detachment were observed . Increasing extracellular calcium enhanced sebocyte numbers , induced epithelial mor phology and reduced lipogenesis . Moreover , a reduction in extracellular calcium reduced E-cadherin and enhanced caspase 3 / 7 activity ( apoptosis ), whereas calcium chelation by EGTA ( ethylene glycolbis ( β-aminoethyl ether ) -N , N , N ’, N ’ -tetraacetic acid ) resulted in enhanced lipogenesis . 1,25 ( OH ) 2D3 decreased sebaceous lipogenesis , but also induced signs of autophagy . In the clinical study , patients and controls exhibited normal serum calcium levels , whereas younger acne patients presented higher levels than older patients and controls . In addition , younger acne patients presented lower 1,25 ( OH ) 2D3 levels than did older ones . In conclusion , extracellular calcium and 1,25 ( OH ) 2D3 regulate sebocyte morphology , increase cell numbers , decrease sebaceous lipogenesis and induce cell autophagy in vitro . The increased ionized calcium and the reduced 1,25 ( OH ) 2D3 levels detected in the serum of younger patients with acne may contribute respectively to increased sebaceous gland volume and enhanced lipogenesis .
Key words : calcium ; vitamin D ; dihydroxyvitamin D3 ; sebocytes ; differentiation ; proliferation ; lipids ; autophagy ; acne .
Accepted Aug 29 , 2016 ; Epub ahead of print Aug 30 , 2016 Acta Derm Venereol 2017 ; 97 : 313 – 320 .
Corr : Christos C . Zouboulis , Departments of Dermatology , Venereo logy , Allergology and Immunology , Dessau Medical Center , Auenweg 38 , DE- 06847 Dessau , Germany . E-mail : christos . zouboulis @ klinikum-dessau . de
* Preliminary results of this work were presented as posters at the Society for Investigative Dermatology 2005 , Arbeitsgemeinschaft Dermatologische Forschung 2012 and the European Society for Dermatological Research 2012 meetings , and as a lecture at the Entretiens d ’ Avène 2014 .
1α , 25-dihydroxyvitamin D 3
( 1,25 ( OH ) 2D3 ) was studied in the treatment of acne by Maynard as early as 1938 ( 1 ), followed by Cerri ( 2 ), Carli ( 3 ) and Garnier ( 4 ). However , to our knowledge , no previous clinical studies have been performed on serum levels of 1,25 ( OH ) 2D3 in patients with acne , and the use of vitamin supplementation in the absence of obvious deficiency has been logically criticized ( 5 ). In a current systematic review of off-label uses of topical 1,25 ( OH ) 2D3 in dermatology , seborrhoea and acne were not among the disorders evaluated ( 6 ). Moreover , there are no references on serum levels of calcium ( Ca 2 + ) in acne , despite the fact that , in several studies , treatment of acne with isotretinoin has been shown to modify circulating 1,25 ( OH ) 2D3 and Ca 2 + levels ( 7 – 10 ).
Calcium ions play a major role in the regulation of keratinocyte growth and differentiation . Normal keratinocytes cultured in low extracellular Ca 2 + ( ecCa 2 + ) do not differentiate , whereas they proliferate rapidly . On the other hand , high ecCa 2 + increases intracellular Ca 2 + ( icCa 2 + ) and , together with 1,25 ( OH ) 2D3 , regulates a sequential turning on and off of the genes possessing response elements , as well as activating the enzymes that induce keratinocyte differentiation and trigger apoptosis ( 11 ). The modulation of icCa 2 + in vitro , also through 1,25 ( OH ) 2D3 ( 12 ), has been a useful tool to illuminate keratinocyte biology ( 12 ) and various related skin diseases , such as Darier ’ s disease and Hailey-Hailey disease , where mutations in Ca 2 + ATPases ( SERCA2 , SPCA1 ) have been detected ( 11 ).
Beyond keratinocytes , Ca 2 + is increasingly being recognized as a central signal transmitter in other cells , including sebocytes ( 13 ). Sebaceous glands are specialized skin appendages committed to differentiate , synthesize and secrete lipids , which , together with cell debris , form the sebum . Sebocytes are grouped into glandular acini , which are composed of an outermost basal proliferating layer and suprabasal differentiating layers that gradually accumulate lipids and finally rupture ( holocrine secretion ) ( 14 , 15 ), found to undergo apoptosis prior to cell bursting and death ( 16 ). Interestingly , the marked stimulatory effect of arachidonic acid on sebaceous lipogenesis ( 17 ) was almost completely abrogated by lowering ecCa 2 + levels to 0.25 mM ( 18 ). In addition , α-melanocyte-stimulating hormone increases
This is an open access article under the CC BY-NC license . www . medicaljournals . se / acta Journal Compilation © 2017 Acta Dermato-Venereologica . doi : 10.2340 / 00015555-2525 Acta Derm Venereol 2017 ; 97 : 313 – 320