Research & Development, Skin Research, Beiersdorf AG, Hamburg, Germany.
J Cosmet Dermatol. 2011 Mar;10(1):15-23. doi: 10.1111/j.1473-2165.2010.00543.x.
The decrease in firmness is a hallmark of skin aging. Accelerated by chronic sun exposure, fundamental changes occur within the dermal extracellular matrix over the years, mainly impairing the collagenous network.
Based on the qualitative and quantitative assessment of skin firmness, in vitro and in vivo studies were carried out to elucidate the effects of topical folic acid and creatine to counteract this age-dependent reduction in the amount of collagen.
PATIENTS/METHODS: Topical application of a commercially available formulation containing folic acid and creatine was performed to study effects on skin firmness in vivo using cutometric analysis. Imaging and quantification of collagen density were carried out using multiphoton laser scanning microscopy (MPLSM). To investigate the effects of these compounds on collagen gene expression, procollagen synthesis, and collagen fibril organization, complementary in vitro studies on cultured fibroblast-populated collagen gels were carried out.
The underlying structural changes in the collagen network of young and aged sun-exposed facial skin in vivo were visualized by MPLSM. Topical application of a folic acid- and creatine-containing formulation significantly improved firmness of mature skin in vivo. Treatment of fibroblast-populated dermal equivalents with folic acid and creatine increased collagen gene expression and procollagen levels and improved collagen fiber density, suggesting that the in vivo effects are based on the overall improvement of the collagen metabolism.
Employing MPLSM, dermal changes occurring in photo-aged human skin were visualized in an unprecedented manner and correlated to a loss of firmness. Treatment of aged skin with a topical formulation containing folic acid and creatine counteracted this age-dependent decline by exerting sustained effects on collagen metabolism. Our results support previous findings on the efficacy of these actives.
皮肤弹性的降低是皮肤衰老的一个标志。由于慢性阳光照射，真皮细胞外基质多年来会发生根本性变化，主要损害胶原纤维网络。
基于皮肤弹性的定性和定量评估，进行了体外和体内研究，以阐明局部应用叶酸和肌酸对抵消这种与年龄相关的胶原蛋白减少的作用。
患者/方法：使用多光子激光扫描显微镜（MPLSM）进行体内皮肤弹性检测，评估商用制剂（含叶酸和肌酸）局部应用对皮肤弹性的影响。
用 MPLSM 可视化了年轻和老化的暴露于阳光的面部皮肤真皮胶原网络的结构变化。局部应用含叶酸和肌酸的制剂可显著改善成熟皮肤的弹性。用叶酸和肌酸处理成纤维细胞填充的真皮等效物可增加胶原蛋白基因表达、前胶原蛋白水平，并改善胶原纤维密度，表明体内作用基于对胶原代谢的整体改善。
采用 MPLSM，以前所未有的方式可视化了光老化人皮肤中发生的真皮变化，并与弹性丧失相关。用含有叶酸和肌酸的局部制剂治疗老化皮肤可通过对胶原代谢产生持续作用来抵消这种与年龄相关的下降。我们的结果支持了这些有效成分的先前发现。
