Maloney M E, Williams M L, Epstein E H, Law M Y, Fritsch P O, Elias P M
J Invest Dermatol. 1984 Oct;83(4):252-6. doi: 10.1111/1523-1747.ep12340321.
Although several abnormalities of lipid metabolism have been associated with abnormal cornification in humans, evidence that these lipids directly provoke abnormal scale is lacking. One recently described example of a lipid abnormality in ichthyosis is absence of the enzyme steroid sulfatase in recessive X-linked ichthyosis (RXLI). This enzyme normally desulfates cholesterol sulfate (CS) and sulfated steroid hormones, including dehydroepiandrosterone sulfate (DHEAS). As a result of this enzyme deficiency, patients with RXLI accumulate CS in their blood and skin. To determine whether sulfated sterols are the specific cause of increased scale, we applied CS, DHEAS, cholesterol, or vehicle alone to the backs of hairless mice. In animals treated with CS, but not with DHEAS or with vehicle, visible scale without erythema appeared after 1 week, peaked at 2 weeks, and then diminished. When the dose of CS was doubled, abnormal scale reappeared and then decreased again. CS-induced scale was reversible, clearing within 3 days of discontinuation of treatment. Because there was no acanthosis, dermal inflammation, abnormal transepidermal water loss, or increased labeling index, it appears that the 3-fold increase in thickness of the stratum corneum in CS-treated animals is due to a direct effect on this layer.
虽然人类脂质代谢的几种异常情况与异常角质化有关，但缺乏这些脂质直接引发异常鳞屑的证据。鱼鳞病中最近描述的一个脂质异常的例子是隐性X连锁鱼鳞病（RXLI）中缺乏类固醇硫酸酯酶。这种酶通常使硫酸胆固醇（CS）和硫酸化类固醇激素，包括硫酸脱氢表雄酮（DHEAS）脱硫酸。由于这种酶缺乏，RXLI患者在血液和皮肤中积累CS。为了确定硫酸化固醇是否是鳞屑增加的具体原因，我们将CS、DHEAS、胆固醇或单独的赋形剂涂抹在无毛小鼠的背部。在用CS处理的动物中，而非用DHEAS或赋形剂处理的动物中，1周后出现无红斑的可见鳞屑，2周时达到峰值，然后减少。当CS剂量加倍时，异常鳞屑再次出现，然后再次减少。CS诱导的鳞屑是可逆的，在停止治疗后3天内消退。由于没有棘层增厚、皮肤炎症、异常的经表皮水分流失或增加的标记指数，似乎CS处理动物的角质层厚度增加3倍是由于对该层的直接作用。
