Sustained Intramural Retention and Regional Redistribution Following Local Vascular Delivery of Polylactic-Coglycolic Acid and Liposomal Nanoparticulate Formulations Containing Probucol

Nanoparticles for Detection and Treatment of Peripheral Arterial Disease

Peripheral arterial disease (PAD) is defined as a slow, progressive disorder of the lower extremity arterial vessels characterized by chronic narrowing that often results in occlusion and is associated with loss of functional capacity. Although the PAD occurrence rate is increasing in the elderly population, outcomes with current treatment strategies are suboptimal. Hence, there is an urgent need to develop new technologies that overcome limitations of traditional modalities for PAD detection and therapy. In this Review, the application of nanotechnology as a tool that bridges the gap in PAD diagnosis and therapy is in focus. Several materials including synthetic, natural, biodegradable, and biocompatible materials are used to develop nanoparticles for PAD diagnostic and/or therapeutic applications. Moreover, various recent research approaches are being explored to diagnose PAD through multimodality imaging with different nanoplatforms. Further efforts include targeted delivery of various therapeutic agents using nanostructures as carriers to treat PAD. Last, but not least, despite being a fairly new field, researchers are exploring the use of nanotheranostics for PAD detection and therapy.

The Lutonix® drug-coated balloon: A novel drug delivery technology for the treatment of vascular disease

Local drug delivery of an anti-proliferative drug from balloon catheter systems to the site of arterial injury has been attempted repeatedly over the years with limited success in drug uptake and retention. Accessibility of the drug at the site is critical to combat the body's response to the procedural trauma of angioplasty. Recently, formulations have been designed which achieve delivery of therapeutic doses of the anti-proliferative drug paclitaxel to arteries with higher efficiency and longer tissue retention. These formulations succeed through formation of a drug reservoir in the artery wall enabling release after the initial angioplasty procedure. These formulations have become the cornerstone of several drug coated balloon (DCB) technologies which have found an initial, broad therapeutic application in the treatment of stenosis of the superficial femoral artery (SFA). DCBs achieve drug delivery while leaving no implant behind and represent a new class of combination products developed at the interface of engineering, chemistry and medical science. This review article summarizes the development of the LUTONIX® drug coated balloon catheter. The introduction of DCB technology has provided clinicians and patients with new SFA treatment options while ongoing clinical evidence in additional vascular beds is generated.

Delivery of Polymeric Nanoparticles to Target Vascular Diseases

Current advances in nanotechnology have paved the way for the early detection, prevention and treatment of various diseases such as vascular disorders and cancer. These advances have provided novel approaches or modalities of incorporating or adsorbing therapeutic, biosensor and targeting agents into/on nanoparticles. With significant progress, nanomedicine for vascular therapy has shown significant advantages over traditional medicine because of its ability to selectively target the disease site and reduce adverse side effects. Targeted delivery of nanoparticles to vascular endothelial cells or the vascular wall provides an effective and more efficient way for early detection and/or treatment of vascular diseases such as atherosclerosis, thrombosis and Cerebrovascular Amyloid Angiopathy (CAA). Clinical applications of biocompatible and biodegradable polymers in areas such as vascular graft, implantable drug delivery, stent devices and tissue engineering scaffolds have advanced the candidature of polymers as potential nano-carriers for vascular-targeted delivery of diagnostic agents and drugs. This review focuses on the basic aspects of the vasculature and its associated diseases and relates them to polymeric nanoparticle-based strategies for targeting therapeutic agents to diseased vascular site.

Role of biomaterials in prevention of in-stent restenosis

Coronary balloon angioplasty and coronary stenting are the procedures used in healing coronary artery disease. However, injury of arteries during angioplasty and stenting causes cell stimulations in tissue. Cell movement and thrombosis lead to re-narrowing of widened vessel called restenosis. Several new types of carriers and technology have been developed to suppress and/or prevent restenosis. Authors review the polymeric materials featured in drug/gene carrier systems, nanovehicles, and stent coating materials against restenosis.

Nanomedicine approaches in vascular disease: a review

Nanomedicine approaches have revolutionized the treatment of cancer and vascular diseases, where the limitations of rapid nonspecific clearance, poor biodistribution and harmful side effects associated with direct systemic drug administration can be overcome by packaging the agents within sterically stabilized, long-circulating nanovehicles that can be further surface-modified with ligands to actively target cellular/molecular components of the disease. With significant advancements in genetics, proteomics, cellular and molecular biology and biomaterials engineering, the nanomedicine strategies have become progressively refined regarding the modulation of surface and bulk chemistry of the nanovehicles, control of drug release kinetics, manipulation of nanoconstruct geometry and integration of multiple functionalities on single nanoplatforms. The current review aims to capture the various nanomedicine approaches directed specifically toward vascular diseases during the past two decades. Analysis of the promises and limitations of these approaches will help identify and optimize vascular nanomedicine systems to enhance their efficacy and clinical translation in the future.

FROM THE CLINICAL EDITOR

Nanomedicine-based approaches have had a major impact on the treatment and diagnosis of malignancies and vascular diseases. This review discusses various nanomedicine approaches directed specifically toward vascular diseases during the past two decades, highlighting their advantages, limitations and offering new perspectives on future applications.

Nanotechnology for the treatment of coronary in stent restenosis: a clinical perspective

Coronary in stent restenosis remains a significant limitation to the long term efficacy of coronary artery stent placement. In this review the authors review the pathophysiology of coronary in stent restenosis, together with an overview of the current treatment modalities. The potential clinical utility of nanotechnology is also reviewed.The first human safety trial of systemic nanoparticle paclitaxel (nab-paclitaxel) for in stent restenosis (SNAPIST-I) is discussed. The results showed no significant adverse advents attributable to the nab-paclitaxel at 10 or 30 mg/m2, although moderate neutropenia, sensory neuropathy and mild to moderate reversible alopecia occurred at higher doses. No major adverse cardiac events were recorded at 2 months, whilst at 6 months, 4 target lesions required revascularisation. The investigators concluded therefore that systemic nab-paclitaxel was well tolerated at a dose of <70 mg/m2. To date however, no formal clinical evaluation has been reported as to the clinical utility of nab-paclitaxel, or any of the nano preparations discussed, for the suppression of coronary in stent restenosis.

Separate and combined effects of local and continuous intravenous administration of beta-cyclodextrin tetradecasulfate on intimal hyperplasia after angioplasty in porcine coronary arteries

BACKGROUND

Beta-Cyclodextrin tetradecasulfate binds fibroblast growth factors and possesses anticoagulant properties. This study was designed to assess the separate and combined effects of local intramural delivery and intravenous administration of beta-cyclodextrin tetrade-casulfate on neointimal formation and arterial damage following angioplasty.

METHODS AND RESULTS

Fifty-two pigs randomized into four groups underwent coronary artery angioplasty: 1) control, 2) continuous intravenous infusion of 100 mg/kg/d of beta-cyclodextrin tetradecasulfate, 3) intramural delivery of 1250 mg beta-cyclodextrin tetradecasulfate, 4) intramural delivery of 1250 mg beta-cyclodextrin tetradecasulfate followed by continuous intravenous infusion of 100 mg/kg/d. Fourteen days after injury, morphometric analysis revealed that arteries randomized to the intravenous beta-cyclodextrin tetradecasulfate groups had a decreased normalized neointima area: control, 3.03 +/- 0.75 mm(2); intravenous, 1.67 +/- 0.73 mm(2) (40% decrease; P < 10(-7)); intravenous plus local, 1.95 +/- 0.76 mm(2) (30% decrease; P < 10(-5)). There was no difference in neointimal response following local beta-cyclodextrin tetradecasulfate delivery only (2.82 +/- 1.14 mm(2)). Coronary arterial damage, defined as aneurysm, dissection, adventitial rupture, and retromedial hematoma was similar in all groups (12% in control and local groups, 10% in the intravenous group, 14% in the intravenous plus local; NS). Bleeding complications were more frequent in the intravenous and intravenous plus local groups compared to the local and control groups (23%vs 7.6% and 0%, respectively; P < 0.05).

CONCLUSIONS

Continuous intravenous administration of beta-cyclodextrin tetradecasulfate substantially reduced intimal hyperplasia, while intramural delivery had no effect, indicating that a single bolus of beta-cyclodextrin tetradecasulfate did not reduce intimal hyperplasia. There was no additive effect of local intramural delivery of beta-cyclodextrin tetradecasulfate. However, local delivery of beta-cyclodextrin tetradecasulfate induced less bleeding complications and did not lead to additional arterial injury, indicating that local delivery of an anticoagulant does not cause additional arterial injury.

Transforming growth factor-beta: a promising target for anti-stenosis therapy

Transforming growth factor-beta (TGF-beta) is the general name for a family of cytokines which have widespread effects on many aspects of growth and development. The TGF-beta isoforms are produced by most cell types and exert a wide range of effects in a context-dependent autocrine, paracrine or endocrine fashion via interactions with distinct receptors on the cell surface. TGF-beta is involved in the wound healing process and, thus plays a significant role in the formation of a restenotic lesion after percutaneous transluminal coronary angioplasty (PTCA) or stenting. Perhaps because of its wide-ranging effects, TGF-beta is usually released from cells in a latent form, and its activation and signaling are complex. Manipulation of the TGF-beta1, TGF-beta2, and TGF-beta3 isoforms by inhibiting their expression, activation, or signaling reduces scarring and fibrosis in animal models. However, to date, few have reached clinical trial. This review summarizes current knowledge on the activation and signaling of TGF-beta, and focuses on the anti-TGF-beta strategies which may lead to clinical applications in the prevention of restenosis following PTCA or stenting.