Transdermal iontophoresis as an in-vivo technique for studying microvascular physiology

Assessment of Skin Microvascular Function and Dysfunction With Laser Speckle Contrast Imaging

“…Several protocols exist to perform iontophoresis, including changing the duration of the current stimulation, the duration of rest time before stimulation, the intensity of the stimulation, the number of stimulations, and the duration between stimulations. 50 The polarity of the pharmacological drug determines the polarity of the current administration. Unfortunately, with iontophoresis, the current on its own can cause a current-induced vasodilation.…”

“…The cathodal current effect is more important than the anodal, and the current effect increases with the increase of the charge density (intensityϫduration). 7,50 The vehicle used with the pharmacological drug can also participate in the response with iontophoresis, then inducing a confounding response. 7 Further, it is important to note that among the most-used vehicles, deionized water provides a more important current-induced vasodilation than NaCl when a cathodal current is used.…”

“…51 Different strategies have been evoked to assess and limit this vehicle effect, such as the administration of the vehicle alone by iontophoresis with the identical current application used to deliver the drug or the use of local anesthetics. 7,50 Readers must keep in mind that the influence of the vehicle can depend on the added drug. 52,53 Different drugs can be used to test different pathways, which induce vasodilatation or vasoconstriction (Table 2).…”

Axon reflex-related hyperemia induced by short local heating is reproducible

“…The axon reflex (AR) is activated by the sensitization of sensory afferents (Cracowski et al, 2006;Kramer et al, 2004;Tesselaar and Sjöberg, 2011) and then triggers the release of calcitonin gene-related peptide and substance P, dilates blood vessels, and increases vascular permeability within the receptive field of activated neurons (Wallengren and Hakanson, 1987;Weidner et al, 2000). The AR flare, i.e.…”

Whole finger iontophoresis of sodium nitroprusside to increase blood flow in patients with systemic sclerosis: Influence of concentration

“…Iontophoresis is a method of delivering drugs locally through the skin and relies on a low voltage electrical current to propel charged particles (carried in solution) across the dermis (Tesselaar and Sjoberg, 2011). Iontophoresis of vasodilating agents, in combination with vascular imaging has been used for many years as a non-invasive in-vivo method of assessing vascular reactivity and endothelial function, including in studies of patients with RP and SSc (Anderson et al, 1996(Anderson et al, , 1999Khan et al, 1997;La Civita et al, 1998;Khan and Belch, 1999;Hettema et al, 2009).…”