Department of Pharmacy, Uppsala University, Sweden.
AlzeCure Foundation, Karolinska Institute Science Park, Huddinge, Sweden.
Eur J Pain. 2018 May;22(5):889-903. doi: 10.1002/ejp.1175. Epub 2018 Jan 26.
The transient receptor potential vanilloid receptor 1 (TRPV1) is a nonselective cation channel involved in the mediation of peripheral pain to the central nervous system. As such, the TRPV1 is an accessible molecular target that lends itself well to the understanding of nociceptive signalling. This study encompasses preclinical investigations of three molecules with the prospect to establish them as suitable analgesic model compounds in human intradermal pain relief studies.
The inhibitory effectiveness was evaluated by means of in vitro assays, TRPV1 expressing Chinese hamster ovary cells (CHO-K1) and rat dorsal root ganglion cultures in fluorescent imaging plate reader and whole cell patch clamp systems, as well as in vivo by capsaicin-evoked pain-related behavioural response studies in rat. Secondary pharmacology, pharmacokinetics and preclinical safety were also assessed.
In vitro, all three compounds were effective at inhibiting capsaicin-activated TRPV1. The concentration producing 50% inhibition (IC ) determined was in the range of 3-32 nmol/L and 10-501 nmol/L using CHO-K1 and dorsal root ganglion cultures, respectively. In vivo, all compounds showed dose-dependent reduction in capsaicin-evoked pain-related behavioural responses in rat. None of the three compounds displayed any significant activity on any of the secondary targets tested. The compounds were also shown to be safe from a toxicological, drug metabolism and pharmacokinetic perspective, for usage in microgram doses in the human skin.
The investigated model compounds displayed ideal compound characteristics as pharmacological and translational tools to address efficacy on the human native TRPV1 target in human skin in situ.
This work details the pharmaceutical work-up of three TRPV1-active investigational compounds, to obtain regulatory approval, for subsequent use in humans. This fast and cost-effective preclinical development path may impact research beyond the pain management area, as it allows human target engagement information gathering early in drug development.
瞬时受体电位香草酸受体 1（TRPV1）是一种非选择性阳离子通道，参与外周疼痛向中枢神经系统的传递。因此，TRPV1 是一个易于接近的分子靶点，非常适合理解伤害性信号。本研究涵盖了三种分子的临床前研究，有望将它们确立为人类皮内疼痛缓解研究中合适的镇痛模型化合物。
通过体外试验、表达 TRPV1 的中国仓鼠卵巢细胞（CHO-K1）和大鼠背根神经节培养物的荧光成像板读数和全细胞膜片钳系统，以及大鼠辣椒素诱发的疼痛相关行为反应研究，评估抑制效力。还评估了次要药理学、药代动力学和临床前安全性。
在体外，三种化合物均能有效抑制辣椒素激活的 TRPV1。使用 CHO-K1 和背根神经节培养物，确定的 50%抑制浓度（IC ）分别在 3-32 nmol/L 和 10-501 nmol/L 范围内。在体内，所有化合物均表现出剂量依赖性地减少大鼠辣椒素诱发的疼痛相关行为反应。三种化合物在测试的任何次要靶点上均未显示出任何显著活性。从毒理学、药物代谢和药代动力学的角度来看，这些化合物在微克剂量下用于人体皮肤也是安全的。
研究的模型化合物表现出理想的化合物特征，作为药理学和转化工具，可在原位解决人类皮肤中天然 TRPV1 靶标的疗效问题。
这项工作详细介绍了三种 TRPV1 活性研究化合物的药物开发情况，以获得监管批准，随后在人类中使用。这种快速且具有成本效益的临床前开发途径可能会影响疼痛管理领域以外的研究，因为它允许在药物开发早期收集人类靶标参与信息。
