Notwithstanding the many promising targets of stem cell-based therapy thus far discussed, stem cell therapeutic are hardly a panacea, and many disorders do not yet lend themselves to cell replacement-based treatment strategies, whether by virtue of poorly understood or inimical disease environments, irreproducible circuit complexity, unfavorable risk-and cost-benefit profiles, or already available treatment strategies. This section addresses these less attractive disease targets, in terms of both current efforts at developing cell-based treatments for them, the limitations of those efforts, and - at least in some cases - the efforts being made to surmount those limitations.
