INVESTIGATIVE REPORT
313
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