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Background: Circulating angiogenic cells (CACs) are peripheral blood cells whose functional capacity inversely correlates with cardiovascular risk and that have therapeutic benefits in animal models of cardiovascular disease. However, donor age and disease state influence the efficacy of autologous cell therapy. We sought to determine whether age or coronary artery disease (CAD) impairs the therapeutic potential of CACs for myocardial infarction (MI) and whether the use of ex vivo gene therapy to overexpress endothelial nitric oxide (NO) synthase (eNOS) overcomes these defects., Methods and Results: We recruited 40 volunteers varying by sex, age (< or ≥45 years), and CAD and subjected their CACs to well-established functional tests. Age and CAD were associated with reduced CAC intrinsic migration (but not specific response to vascular endothelial growth factor, adherence of CACs to endothelial tubes, eNOS mRNA and protein levels, and NO production. To determine how CAC function influences therapeutic potential, we injected the 2 most functional and the 2 least functional CAC isolates into mouse hearts post MI. The high-function isolates substantially improved cardiac function, whereas the low-function isolates led to cardiac function only slightly better than vehicle control. Transduction of the worst isolate with eNOS cDNA adenovirus increased NO production, migration, and cardiac function of post-MI mice implanted with the CACs. Transduction of the best isolate with eNOS small interfering RNA adenovirus reduced all of these capabilities., Conclusions: Age and CAD impair multiple functions of CACs and limit therapeutic potential for the treatment of MI. eNOS gene therapy in CACs from older donors or those with CAD has the potential to improve autologous cell therapy outcomes., (© 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.)

Pleiotrophin (PTN) is a growth factor with both pro-angiogenic and limited pro-tumorigenic activity. We evaluated the potential for PTN to be used for safe angiogenic gene therapy using the full length gene and a truncated gene variant lacking the domain implicated in tumorigenesis. Mouse myoblasts were transduced to express full length or truncated PTN (PTN or T-PTN), along with a LacZ reporter gene, and injected into mouse limb muscle and myocardium. In cultured myoblasts, PTN was expressed and secreted via the Golgi apparatus, but T-PTN was not properly secreted. Nonetheless, no evidence of uncontrolled growth was observed in cells expressing either form of PTN. PTN gene delivery to myocardium, and non-ischemic skeletal muscle, did not result in a detectable change in vascularity or function. In ischemic hindlimb at 14 days post-implantation, intramuscular injection with PTN-expressing myoblasts led to a significant increase in skin perfusion and muscle arteriole density. We conclude that (1) delivery of the full length PTN gene to muscle can be accomplished without tumorigenesis, (2) the truncated PTN gene may be difficult to use in a gene therapy context due to inefficient secretion, (3) PTN gene delivery leads to functional benefit in the mouse acute ischemic hindlimb model.

Delivery of bone marrow cells (BMCs) to the heart has substantially improved cardiac function in most rodent models of myocardial infarction (MI), but clinical trials of BMC therapy have led to only modest improvements. Rodent models typically involve intramyocardial injection of BMCs from distinct donor individuals who are healthy. In contrast, autologous BMCs from individuals after MI are used for clinical trials. Using BMCs from donor mice after MI, we discovered that recent MI impaired BMC therapeutic efficacy. MI led to myocardial inflammation and an increased inflammatory state in the bone marrow, changing the BMC composition and reducing their efficacy. Injection of a general anti-inflammatory drug or a specific interleukin-1 inhibitor to donor mice after MI prevented this impairment. Our findings offer an explanation of why human trials have not matched the success of rodent experiments and suggest potential strategies to improve the success of clinical autologous BMC therapy.