Fig 1.
Transdermal arterial gasotransmitter sensor (TAGS) approach for determining endothelial dysfunction. Hydrogen sulfide (H2S) is a reactive thiol with reducing activities that is synthesized within the vasculature primarily by cystathionine γ-lyase (CSE). H2S can react with cysteine residues on multiple proteins through sulfhydration, shown to modulate the function of multiple ion channels, structural proteins, and enzymes to cause vasorelaxation within seconds, and its effects persist to angiogenesis within days of exposure to H2S, illustrating how this molecule is critical to angiogenic pathways. Therefore, from the TAGS measurement point of view, the two mechanisms giving rise to bioavailability of H2S within the dermal layer, as shown on the left, are local production of H2S by the endothelial layer and delivery of systemic H2S to the measurement location. The TAGS transdermal sampler placed on the surface of the skin collects and measures the portion reaching the surface, proportional to the skin bioavailability (concentration) of H2S.