Clinical trials of adult stem cell therapy for peripheral artery disease.

Peripheral artery disease (PAD) refers to noncoronary vascular disease affecting the peripheral arteries. Most commonly the term is applied to occlusive arterial disease affecting the limb arteries, typically due to atherosclerosis. Preclinical studies indicate that a variety of stem cell therapies provide growth factors and cytokines for therapeutic angiogenesis. Small clinical trials with bone marrow mononuclear cells, as well as other cell types, have shown promise. However, mechanisms of therapeutic effect, if any, are not understood. Definitive clinical trials are needed to determine if there are any beneficial effects on functional capacity or morbidity.