Elias P M, Nau P, Hanley K, Cullander C, Crumrine D, Bench G, Sideras-Haddad E, Mauro T, Williams M L, Feingold K R
Dermatology and Medicine (Metabolism) Services, Veterans Administration Medical Center, Department of Dermatology, University of California School of Medicine, San Francisco 94121, USA.
J Invest Dermatol. 1998 Apr;110(4):399-404. doi: 10.1046/j.1523-1747.1998.00151.x.
The epidermal permeability barrier forms late in gestation, coincident with decreased lipid synthesis, increased lipid processing, and development of a mature, multi-layered stratum corneum. Prior studies have shown that changes in the epidermal Ca++ gradient in vivo regulate lamellar body secretion and lipid synthesis, and modulations in extracellular Ca++ in vitro also regulate keratinocyte differentiation. We asked here whether a Ca++ gradient forms in fetal epidermis in utero, and whether its emergence correlates with key developmental milestones of barrier formation and stratum corneum development. Using either ion precipitation or proton induced X-ray emission analysis of fetal mouse and rat skin, we showed that a Ca++ gradient is not present at gestational days 16-18, prior to barrier formation, and that a gradient forms coincident with the emergence of barrier competence (day 19, mouse; day 20, rat) prior to birth. These results are consistent with a role for Ca++ in the regulation of key metabolic events leading to barrier formation. Whether the calcium gradient is formed actively or passively remains to be determined.
表皮通透屏障在妊娠后期形成，与脂质合成减少、脂质加工增加以及成熟的多层角质层的发育同时发生。先前的研究表明，体内表皮钙离子梯度的变化调节板层小体分泌和脂质合成，体外细胞外钙离子的调节也调节角质形成细胞分化。我们在此询问子宫内胎儿表皮中是否形成钙离子梯度，以及其出现是否与屏障形成和角质层发育的关键发育里程碑相关。使用离子沉淀或质子诱导X射线发射分析胎儿小鼠和大鼠皮肤，我们发现屏障形成前的妊娠第16 - 18天不存在钙离子梯度，并且在出生前屏障能力出现时（小鼠第19天；大鼠第20天）形成梯度。这些结果与钙离子在导致屏障形成的关键代谢事件调节中的作用一致。钙离子梯度是主动还是被动形成仍有待确定。
