Artificial sweeteners sucralose and acesulfame potassium: A bittersweet story for the cardiovascular system?

Abstract

Artificial sweeteners (AS) are well known to activate two categories of receptors; sweet taste receptor with high affinity and bitter taste receptors with low affinity. Interestingly, recent data from our and other groups suggested that these two receptors families are expressed throughout the arterial tree. Therefore, it could be interesting to explore if AS may have an impact on vascular function, and to decipher the role of these taste receptors. The aims of this ongoing work is to investigate whether AS, like sucralose and acesulfame potassium (AceK) (1) exhibit vasomotor effect and (2) in that case determine the underlying mechanisms. Biomolecular and functional investigations have been performed on isolated rodent aortas, human dermal micro-arteries and omental arteries. Ex vivo vasomotor function was assessed using isometric tension measurements in organ bath systems. We first confirmed that both endothelial and smooth muscle cells from rodent and human arteries express the transcripts encoding for TAS1R2 and TAS1R3; the heterodimer receptor known to be responsible for the sweet taste. Our ex vivo data showed that only high concentrations (about 10 mM) of AceK and sucralose induce vasomotor responses. While AceK exhibited a vasoconstrictive effect, sucralose induced vasorelaxation. Both responses were found to be independent of the endothelium. Pharmacological inhibition (gurmarin and lactisol) and the use of a TAS1R3 KO mice model demonstrated that AS vasomotor effects do not rely on the sweet taste receptors. In contrast, inhibition of TAS2Rs abolished all responses suggesting that bitter taste receptors are more likely responsible for the AS-induced vascular effects. Additionally, our last observations show that the vasoconstrictive effect of AceK is mediated by RhoA/ROCK pathway. These evidences support the idea that AS can alter vasomotor signaling in the smooth muscle cells. These acute effects are probably mediated by the bitter taste receptor family. Their activation at the vascular level as well as the underlying pathways remains poorly understood, and the physiopathological consequences need to be further investigated.