The purpose of this study is to determine whether autologous bone marrow-derived stem cells are effective in the treatment of lower extremity ischemia.

Critical limb ischemia (CLI) is a debilitating and disabling disease. Symptoms include pain at rest, loss of tissue integrity, distal amputations and have a major impact on the quality of life. Despite recent advances in surgical vascular procedures, a large number of patients (approximately 40%) are not eligible for these revascularization procedures. New strategies for revascularization need to be explored. Besides, in some cases results of such interventions do not give desirable effect, search of new methods of treatment therefore is necessary. Recent evidence indicates that bone marrow-derived mononuclear cells (BM-MNC) are a potential new therapeutic target.

Inclusion Criteria:

• Critical lower limb ischemia, defined as ischemic pain at rest and / or the presence of minor tissue loss, with the possibility of healing.
• Failure of conventional medical treatment and attempts to open or percutaneous revascularization before, with an observation period of two months after the last attempt at revascularization.
• Patients considered at high risk for new revascularization procedure by at least two independent observers.

Exclusion Criteria:

• Expected life span less than six months
• Large tissue loss in the ischemic limb indicating the need for limb amputation in the short term.
• Evidence of osteomyelitis in the ischemic extremity.
• Current or previous history of neoplasia.
• Unstable angina, recent stroke or other medical condition that contraindicate anesthesia for bone marrow aspiration.
• Proliferative retinopathy.
• Debilitating disease with a life span less than one year.
• Myelofibrosis, myelodysplasia or other diseases that affect the bone marrow.
• Use of alcohol in excess of twice-daily doses or history of illicit drug use.
• Need for continuous high doses of drug therapy with steroids (more than 7.5 mg/day).
• Positivity for HIV or syphilis