Critical appraisal of stem cell therapy in peripheral arterial disease: Do current scientific breakthroughs offer true promise or false hope?

Abstract

Over the last forty years in the field of peripheral arterial disease, there has been a plethora of research into cell-based therapies for tissue repair, regenera tion and angiogenesis, progressing from pro tein-based therapies to gene therapies to stem cell research. Initial pre-clinical research successes have given birth to a whole industry, aimed at translating these laboratory hopes into clinical successes. However, heretofore these expected clinical results have failed to materialize, in part due to the lack of attention to the ischaemic desert like tissue and systemically diseased patient into which the stem cells are being implanted. Unsatisfactory clinical outcomes on the treatment of Critical Limb Ischaemia (CLI) have forced researchers to direct their efforts to the less intimidating challenge of claudication and to lower their clinical out come thresholds from superior to “non-inferior”. Major questions on safety and durability have also arisen. What needs to be objectively established is the impact on the net health outcome of these therapies. Infusion or injection for stem cell therapy is still considered ex perimental and investigational. In this review we ex amine the clinical evidence for angiogenic therapies, focusing specifically on stem cell trials, in an attempt to answer the question “Is stem cell therapy a failed ex periment or will there be light at the end of the tun nel?”