Ceramidase activity in bacterial skin flora as a possible cause of ceramide deficiency in atopic dermatitis
Ceramidase activity in bacterial skin flora as a possible cause of ceramide deficiency in atopic dermatitis
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DOI：
10.1128/cdli.6.1.101-104.1999
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发表时间：
1999-01-01
期刊：
影响因子：
--
通讯作者：
Imayama, S
中科院分区：
文献类型：
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作者：
Ohnishi, Y;Okino, N;Imayama, S
特应性皮炎(AD)患者表皮角质层神经酰胺含量显著降低，由于神经酰胺是角质层细胞外间隙的主要保水分子，这种降低损害了表皮的通透性屏障，导致AD特有的干燥和易抗原渗透的皮肤。另一方面，这类患者的皮肤经常被细菌定植，最典型的是金黄色葡萄球菌，具有与鞘磷脂代谢相关的鞘磷脂酶基因。因此，我们试图通过薄层层析分析细菌分泌的神经鞘磷脂相关酶活性，确定25名AD患者和24名健康人皮肤神经酰胺含量和细菌菌群之间的可能相关性。检测结果表明，从AD患者皮损和非皮损皮肤获得的细菌群中分泌的神经酰胺酶显著多于从健康人皮肤获得的细菌群；神经酰胺酶将神经酰胺分解为鞘氨醇和脂肪酸；神经鞘磷脂酶将神经鞘磷脂分解为神经酰胺和磷胆碱，从AD患者和健康对照组相似水平的所有类型皮肤获得的细菌群中分泌。AD患者皮肤上有神经酰胺酶分泌菌的定植，提示微生物与表皮角质层神经酰胺缺乏有关，神经酰胺缺乏通过损害通透性屏障而增加AD患者皮肤的过敏性。
A marked decrease in the content of ceramide has been reported in the horny layer of the epidermis in atopic dermatitis (AD), This decrease impairs the permealbility barrier of the epidermis, resulting in the characteristic dry and easily antigen-permeable skin of AD, since ceramide serves as the major water-holding molecule in the extracellular space of the horny layer. On the other hand, the skin of such patients is frequently colonized by bacteria, most typically by Staphylococcus aureus, possessing genes such as those for sphingomyelinase, which are related to sphingolipid metabolism. We therefore tried to identify a possible correlation between the ceramide content and the bacterial flora obtained from the skin of 25 patients with AD versus that of 24 healthy subjects, using a thin-layer chromatographic assay of the sphingomyelin-associated enzyme activities secreted from the bacteria. The findings of the assay demonstrated that ceramidase, which breaks ceramide down into sphingosine and fatty acid, was secreted significantly more from the bacterial flora obtained from both the lesional and the nonlesional skin of patients with AD than from the skin of healthy subjects; sphingomyelinase, which breaks sphingomyelin down into ceramide and phosphorylcholine, was secreted from the bacterial flora obtained from all types of skin at similar levels for the patients with AD and the healthy controls. The finding that the skin of patients with AD is colonized by ceramidase-secreting bacteria thus suggests that microorganisms are related to the deficiency of ceramide in the horny layer of the epidermis, which increases the hypersensitivity of skin in AD patients by impairing the permeability barrier.