Leptin is of major significance to ME/CFS, since fatigue levels in ME/CFS correlate to leptin levels (see here). As leptin levels go up, this increases fatigue in ME/CFS. So any leptin resistance would presumably lead to increased fatigue in ME/CFS.
Now it seems that ER stress induces leptin resistance. Refs: 1 2
However, TUDCA is a leptin sensitizer, that can help combat leptin resistance (and thereby lower leptin) by reducing ER stress. Ref: 1 So by this mechanism, TUDCA may be helpful for ME/CFS.
@Hip, would leptin resistance then equate with poor appetite and/or possibly even gastroparesis?
Re bile acids: Also worth noting is that bile helps reduce inflammation by inhibiting gut permeability. They also 'cleanse' endotoxins directly, again, reducing inflammation, in this study w/psoriasis patients.