Objectives

Two CFTR-dependent β-adrenergic sweat rate tests applying intradermal drug injections were reported to better define diagnosis and efficacy of CFTR-directed therapies. The aim of this work was to develop and test a needle-free image-based test and to provide an accurate analysis of the responses.

Methods

The modified method was conducted by applying two successive iontophoresis sessions using the Macroduct device. Efficiency of drug delivery was tested by evaporimetry. Cholinergically stimulated sweating was evoked by pilocarpine iontophoresis. β-adrenergically stimulated sweating was obtained by iontophoresis of isoproterenol and aminophylline in the presence of atropine and ascorbic acid. A nonlinear mixed-effects (NLME) approach was applied to model volumes of sweat and subject-specific effects displaying inter- and intra-subject variability.

Results

Iontophoresis provided successful transdermal delivery of all drugs, including almost neutral isoproterenol and aminophylline. Pilocarpine was used at a concentration ∼130-times lower than that used in the classical Gibson and Cooke sweat test. Addition of ascorbic acid lowered the pH of the solution, made it stable, prevented isoproterenol degradation and promoted drug iontophoresis. Maximal secretory capacity and kinetic rate of β-adrenergic responses were blunted in CF. A cutoff of 5.2 minutes for ET50, the time to reach the half maximal secretion, discriminated CF from controls with a 100% sensitivity and specificity. Heterozygous showed an apparently reduced kinetic rate and a preserved secretory capacity.

Conclusion

We tested a safe, well-tolerated needle-free image-based sweat test potentially applicable in children. Modelling responses by NLME allowed evaluating metrics of CFTR-dependent effects reflecting secretory capacity and kinetic rate.

中文翻译：

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无针离子电渗驱动β-肾上腺素能出汗率试验

目标

据报道，应用皮内药物注射的两项 CFTR 依赖性 β-肾上腺素能出汗率测试可以更好地确定 CFTR 导向疗法的诊断和疗效。这项工作的目的是开发和测试基于无针图像的测试，并提供对响应的准确分析。

方法

修改后的方法是通过使用 Macroduct 设备应用两个连续的离子电渗疗法来进行的。通过蒸发法测试药物递送的效率。毛果芸香碱离子电渗疗法引起胆碱能刺激出汗。在阿托品和抗坏血酸存在下，通过异丙肾上腺素和氨茶碱的离子电渗疗法获得 β-肾上腺素刺激的出汗。非线性混合效应 (NLME) 方法应用于模拟汗液体积和显示受试者间和受试者内变异性的受试者特定效应。

结果

离子电渗疗法提供了所有药物的成功透皮递送，包括几乎中性的异丙肾上腺素和氨茶碱。毛果芸香碱的使用浓度比经典 Gibson 和 Cooke 汗液测试中使用的浓度低 130 倍。添加抗坏血酸降低了溶液的pH值，使其稳定，防止异丙肾上腺素降解并促进药物离子电渗。在 CF 中，β-肾上腺素能反应的最大分泌能力和动力学速率减弱。ET50 的截止时间为 5.2 分钟，即达到最大分泌量一半的时间，以 100% 的敏感性和特异性将 CF 与对照区分开来。杂合子表现出明显降低的动力学速率和保留的分泌能力。

结论

我们测试了一种可能适用于儿童的安全、耐受性良好的基于​​无针图像的汗液测试。NLME 建模响应允许评估反映分泌能力和动力学速率的 CFTR 依赖效应的指标。