TRPA1 and diabetes mellitus: Additionally, methylglyoxal, a reactive metabolite that accumulates intracellularly in diabetes (Brownlee 2001; Nakayama et al. 2008) and chronic kidney disease (Nakayama et al. 2008), is able to directly activate TRPA1 resulting in a painful neuropathy in mice (Eberhardt et al. 2012; Andersson et al. 2013).