Department of Dermatology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
Neuropeptides. 2011 Dec;45(6):417-22. doi: 10.1016/j.npep.2011.07.008. Epub 2011 Sep 3.
Nerve growth factor (NGF) was reported to be increased in the serum and skin of atopic dermatitis (AD) patients, to the extent that serum nerve growth factor levels were proposed to serve as a marker of disease severity. We studied NGF levels in the serum and dermis using skin microdialysis and attempted to correlate them with disease severity. We also examined if potential differences between morning and evening levels of NGF can explain the phenomenon of nocturnal itch. In addition, neurogenic inflammation and itch were induced using histamine iontophoresis in lesional and non-lesional skin and the effect of experimental itch on dermal NGF concentration was examined. We found that systemic (serum) and eczematous skin levels of NGF in AD are significantly lower in comparison to healthy controls. Serum NGF decreases from morning to late afternoon in both groups. Interestingly, serum NGF levels were correlated to disease severity in the morning in AD, although the NGF concentration in AD were significantly lower than in the healthy group. The local itch and neurogenic inflammation induction via experimental histamine reduced local NGF levels in the eczema and non-lesional skin in atopics, but not in the healthy controls, where it was slightly increased. The higher the clinical severity of the eczema, a significantly less pronounced effect of neurogenic inflammation on the local levels of NGF was found. The availability of measurable NGF might be reduced by a higher expression of NGF receptors. The fluctuations of NGF levels during the day suggest a complex modulation of this neurotrophin, potentially linked to stress or to an altered neurophysiological mechanism.
神经生长因子（NGF）在特应性皮炎（AD）患者的血清和皮肤中均有增加，以至于血清神经生长因子水平被提议作为疾病严重程度的标志物。我们使用皮肤微透析研究了血清和真皮中的 NGF 水平，并试图将其与疾病严重程度相关联。我们还检查了 NGF 水平在清晨和傍晚之间的潜在差异是否可以解释夜间瘙痒的现象。此外，我们还通过组胺离子电渗法在病变和非病变皮肤上诱导了神经性炎症和瘙痒，并检查了实验性瘙痒对真皮 NGF 浓度的影响。我们发现，AD 患者的全身性（血清）和湿疹皮肤中的 NGF 水平明显低于健康对照组。两组的血清 NGF 均从清晨下降至下午晚些时候。有趣的是，尽管 AD 组的 NGF 浓度明显低于健康组，但 AD 患者的清晨血清 NGF 水平与疾病严重程度相关。通过实验性组胺诱导的局部瘙痒和神经源性炎症可降低 AD 患者湿疹和非病变皮肤中的局部 NGF 水平，但在健康对照组中，局部 NGF 水平略有增加。湿疹的临床严重程度越高，神经源性炎症对局部 NGF 水平的影响就越不明显。NGF 受体的高表达可能会降低可测量 NGF 的可用性。NGF 水平在白天的波动表明这种神经营养因子的复杂调节，可能与压力或改变的神经生理机制有关。
