Stem cell microencapsulation for therapeutic angiogenesis

Vascular diseases represent a major global health problem and may result in reduced oxygen delivery and tissue ischemia downstream of affected blood vessels. This may result in organ dysfunction or in extreme cases in infarction. Clinically important diseases include ischemia of the heart, brain or limbs. Peripheral arterial disease (PAD) encompasses all noncoronary arterial syndromes, including those of the leg arteries, aorta, carotid, upper extremity and visceral arteries (Norgren et al. 2007). The prevalence of PAD increases with the aging population and is symptomatic in 3-10 percent in the western population. The risk of developing PAD may be increased by metabolic or circulatory abnormalities including diabetes mellitus, hypertension, and obesity, as well as other risks factors 1Regenerative Medicine Institute (REMEDI), National Centre for Biomedical Engineering Science (NCBES) & Department of Medicine, National University of Ireland, Galway, Republic of Ireland. aEmail: [email protected] bEmail: [email protected] cEmail: [email protected] 2Network of Excellence for Functional Biomaterials (NFB), National University of Ireland, Galway, Republic of Ireland. Email: [email protected] Vascular diseases represent a major global health problem and may result in reduced oxygen delivery and tissue ischemia downstream of affected blood vessels. This may result in organ dysfunction or in extreme cases in infarction. Clinically important diseases include ischemia of the heart, brain or limbs. Peripheral arterial disease (PAD) encompasses all noncoronary arterial syndromes, including those of the leg arteries, aorta, carotid, upper extremity and visceral arteries (Norgren et al. 2007). The prevalence of PAD increases with the aging population and is symptomatic in 3-10 percent in the western population. The risk of developing PAD may be increased by metabolic or circulatory abnormalities including diabetes mellitus, hypertension, and obesity, as well as other risks factors 1Regenerative Medicine Institute (REMEDI), National Centre for Biomedical Engineering Science (NCBES) & Department of Medicine, National University of Ireland, Galway, Republic of Ireland. aEmail: [email protected] bEmail: [email protected] cEmail: [email protected] 2Network of Excellence for Functional Biomaterials (NFB), National University of Ireland, Galway, Republic of Ireland. Email: [email protected] *Corresponding author such as smoking habits (Norgren et al. 2007). Patients with PAD may have intermittent claudication or critical limb ischemia (CLI). CLI is a severe form of PAD characterized by chronic ischemic rest pain, ulcers, or gangrene attributed to inadequate blood fl ow or arterial occlusive disease (Norgren et al. 2007). Current treatments for vascular diseases consist of optimal medical management and restoration of blood supply by angioplasty or bypass surgery where possible. However, a considerable percentage of patients (so-called no-option patients) are not ideal candidates for standard revascularization sometimes due to the large area affected, the presence of distal blood vessel disease, high operative risk or other co-morbidities (Diehm and Diehm 2004). When this situation exists in the limbs, amputation becomes the only treatment option. Patients who undergo amputation for peripheral arterial disease have a poor prognosis for life and rehabilitation (Norgren et al. 2007). Patients with coronary artery disease who are not candidates for revascularization may have recurrent episodes of ischemia or develop congestive heart failure (Ware and Simons 1997). Therefore, new therapies for these no-option patients are urgently required. This chapter will focus on treatment of no-option peripheral arterial disease although the general principles may apply to ischemia of any vascular bed.Corresponding author such as smoking habits (Norgren et al. 2007). Patients with PAD may have intermittent claudication or critical limb ischemia (CLI). CLI is a severe form of PAD characterized by chronic ischemic rest pain, ulcers, or gangrene attributed to inadequate blood fl ow or arterial occlusive disease (Norgren et al. 2007). Current treatments for vascular diseases consist of optimal medical management and restoration of blood supply by angioplasty or bypass surgery where possible. However, a considerable percentage of patients (so-called no-option patients) are not ideal candidates for standard revascularization sometimes due to the large area affected, the presence of distal blood vessel disease, high operative risk or other co-morbidities (Diehm and Diehm 2004). When this situation exists in the limbs, amputation becomes the only treatment option. Patients who undergo amputation for peripheral arterial disease have a poor prognosis for life and rehabilitation (Norgren et al. 2007). Patients with coronary artery disease who are not candidates for revascularization may have recurrent episodes of ischemia or develop congestive heart failure (Ware and Simons 1997). Therefore, new therapies for these no-option patients are urgently required. This chapter will focus on treatment of no-option peripheral arterial disease although the general principles may apply to ischemia of any vascular bed.