Systemic nanoparticle paclitaxel (nab-paclitaxel) for in-stent restenosis I (SNAPIST-I): a first-in-human safety and dose-finding study

Drug-Coated Balloons for Treatment of Internal Carotid Artery Restenosis After Stenting: A Single-Center Mid-Term Outcome Study

PURPOSE

Endovascular and surgical treatments of stenosis of the extracranial internal carotid artery (ICA) are common procedures, yet both introduce a risk of restenosis due to endothelial hyperplasia. Drug-coated balloons (DCBs) are designed to decrease neointimal hyperplasia, however rarely used in the neurovascular setting. This study retrospectively analyzes mid-term results of DCB-treated in-stent restenosis (ISR) of the ICA.

MATERIALS AND METHODS

The medical history, comorbidities, and periprocedural data of patients receiving DCB treatment for > 50% ISR of the ICA after carotid artery stenting were analyzed. Follow-up after DCB treatment was performed with Doppler ultrasound. Suspicious cases were checked with CT- or MR-angiography and-if there was agreement between the modalities-validated with digital subtraction angiography. Potential risk factors for restenosis and differences in outcomes after PTA with three types of DCB balloons were evaluated.

RESULTS

DCB treatment was performed in 109 cases, 0.9% of which involved in-hospital major stroke; no minor strokes occurred. A total of 17 patients (15.6%) had recurrent ISR after DCB treatment, after a mean time of 30.2 months (7-85 months). Tobacco use was significantly associated with a higher incidence of recurrent ISR.

CONCLUSION

DCB angioplasty for ISR is an effective treatment that may delay and decrease restenosis. Treating comorbidities and adopting lifestyle changes may additionally help prevent ISR.

Repetition of Paclitaxel-Coated Devices for the Treatment of Lower Extremity Artery Disease: Mortality Outcomes and Predictors

Background

A recent meta-analysis reported late excess mortality in patients treated with paclitaxel-coated devices (PCDs) for symptomatic femoropopliteal disease. However, this finding is controversial.

Objectives

To investigate the impact on mortality and predictors of repeat exposure to PCDs in patients with lower extremity peripheral arterial disease (LE-PAD).

Methods

We analyzed registry patient-level data from two centers. A total of 214 patients were enrolled, and stratified based on terciles of cumulative dose of paclitaxel. We treated 134 patients with a single PCD exposure and 80 with multiple PCD exposures. We used the follow-up index (FUI) in Kaplan-Meier survival estimates to minimize potential selection bias. We used Cox proportional hazard and splines models to determine the predictors of mortality and assess their relationships with mortality.

Results

The mean cumulative dose of paclitaxel was significantly different among groups (6.40 mg vs. 15.06 mg vs. 38.57 mg, p < 0.001). The 5-year FUI (0.93 ± 0.19 vs. 0.94 ± 0.18 vs. 0.95 ± 0.15, p = 0.836) and survival rates were not different (65.4% vs. 51.9% vs. 72.0%, p = 0.148). There was no dose-response association between paclitaxel dosage and death (p = 0.297). The predictors of death were congestive heart failure, stroke, dialysis dependence, neutrophil-lymphocyte ratio (NLR) > 3, age > 71 years, and body mass index (BMI) < 20 kg/m². Spline model analysis validated the non-linear associations between mortality, age, BMI, and NLR.

Conclusions

Repeated PCD exposure for LE-PAD did not result in excess late mortality. Predictors of mortality might change over time, and continuous variables had non-linear relationships with death.

A State-of-the-Art Review: The Percutaneous Treatment of Highly Calcified Lesions

Coronary artery calcification is prevalent in coronary heart disease with its progression being predictive of future adverse cardiac events. Its presence is considered to be a marker of interventional procedural complexity. Several adjunctive percutaneous coronary intervention tools, such as modifying balloons, atherectomy devices and intravascular lithotripsy, now exist to successfully treat calcified lesions. In this state-of-the-art review, a step-wise progression of strategies is described to modify coronary plaque, from well-recognised techniques to techniques that should only be considered when standard manoeuvres have proven unsuccessful. Technology has advanced greatly over the past few decades and we discuss how future technologies might shape percutaneous intervention.

Drug-coated Balloons in the Neurovascular Setting: A Comprehensive, Systematic Review of Current Use and Indications

Background

Drug-coated balloons (DCB) are an established tool in the prevention and treatment of coronary and peripheral artery restenosis. The underlying effects of restenosis resemble those in the neurovascular field, yet data on the use of DCB in cervical and intracranial arteries is rare.

Methods

Medline, and international and major national guidelines and recommendations were systematically searched for data addressing the use of DCB in the neurovascular setting.

Results

Of the 1448 relevant records found in Medline, 166 publications were considered for this review.

Conclusions

Data on the use of DCB in the neurovascular setting show a possible benefit over preceding alternatives, such as self-expanding stents, and balloon-mounted or drug-eluting stents. Nonetheless, the role of DCB remains under-researched, and publications remain lacking.

Biomimetic, ROS-detonable nanoclusters - A multimodal nanoplatform for anti-restenotic therapy

The long-term success of endovascular intervention has long been overshadowed by vessel re-occlusion, also known as restenosis. Mainstream anti-restenotic devices, such as drug-eluting stent (DES) and drug-coated balloon (DCB), were recently shown with suboptimal performances and life-threatening complications, thereby underpinning the urgent need for alternative strategies with enhanced efficacy and safety profile. In our current study, we engineered a multimodal nanocluster formed by self-assembly of unimolecular nanoparticles and surface coated with platelet membrane, specifically tailored for precision drug delivery in endovascular applications. More specifically, it incorporates the combined merits of platelet membrane coating (lesion targetability and biocompatibility), reactive oxygen species (ROS)-detonable "cluster-bomb" chemistry (to trigger the large-to-small size transition at the target site, thereby achieving longer circulation time and higher tissue penetration), and sustained drug release. Using RVX-208 (an emerging anti-restenotic drug under clinical trials) as the model payload, we demonstrated the superior performances of our nanocluster over conventional poly(lactic-co-glycolic acid) (PLGA) nanoparticle. In cultured vascular smooth muscle cell (VSMC), the drug-loaded nanocluster induced effective inhibition of proliferation and protective gene expression (e.g., APOA-I) with a significantly reduced dosage of RVX-208 (1 μM). In a rat model of balloon angioplasty, intravenous injection of Cy5.5-tagged nanocluster led to greater lesion targetability, improved biodistribution, and deeper penetration into injured vessel walls featuring enriched ROS. Moreover, in contrast to either free drug solution or drug-loaded PLGA nanoparticle formulation, a single injection with the drug-loaded nanocluster (10 mg/kg of RVX-208) was sufficient to substantially mitigate restenosis. Additionally, this nanocluster also demonstrated biocompatibility according to in vitro cytotoxicity assay and in vivo histological and tissue qPCR analysis. Overall, our multimodal nanocluster offers improved targetability, tissue penetration, and ROS-responsive release over conventional nanoparticles, therefore making it a highly promising platform for development of next-generation endovascular therapies.

Nanomaterial-Based Drug Targeted Therapy for Cardiovascular Diseases: Ischemic Heart Failure and Atherosclerosis

Cardiovascular diseases (CVDs) represent the most important epidemic of our century, with more than 37 million patients globally. Furthermore, CVDs are associated with high morbidity and mortality, and also increased hospitalization rates and poor quality of life. Out of the plethora of conditions that can lead to CVDs, atherosclerosis and ischemic heart disease are responsible for more than 2/3 of the cases that end in severe heart failure and finally death. Current therapy strategies for CVDs focus mostly on symptomatic benefits and have a moderate impact on the underlying physiopathological mechanisms. Modern therapies try to approach different physiopathological pathways such as reduction of inflammation, macrophage regulation, inhibition of apoptosis, stem-cell differentiation and cellular regeneration. Recent technological advances make possible the development of several nanoparticles used not only for the diagnosis of cardiovascular diseases, but also for targeted drug delivery. Due to their high specificity, nanocarriers can deliver molecules with poor pharmacokinetics and dynamics such as: peptides, proteins, polynucleotides, genes and even stem cells. In this review we focused on the applications of nanoparticles in the diagnosis and treatment of ischemic heart failure and atherosclerosis.

Paclitaxel Exposure and Dosage of Drug-coated Devices for the Treatment of Femoropopliteal Peripheral Artery Disease

The role of paclitaxel in the treatment of femoropopliteal peripheral arterial disease is currently ambiguous. A summary-level meta-analysis of randomised trials published in 2018 demonstrated that paclitaxel-coated devices were associated with an increased all-cause mortality in those who underwent treatment at 2 years and 5 years. Further evaluation has been undertaken to establish whether there is a specific dose response, mechanism or reproducible signal. At this time, there has been no confirmation of dose response, as was initially asserted by the summary-level meta-analysis. No mechanism of harm has been identified. Although an association with increased mortality has been confirmed by patient-level meta-analysis, the strength of the signal has been inconsistent. The information suggests there is only an association between paclitaxel-coated devices and increased all-cause mortality, not causation. The authors encourage additional studies designed to follow long-term results after treatment with paclitaxel-coated devices, using real patient data, before a conclusion can be made.

Immunomodulatory Nanomedicine for the Treatment of Atherosclerosis

Atherosclerosis is the main underlying cause of cardiovascular diseases (CVDs), which remain the number one contributor to mortality worldwide. Although current therapies can slow down disease progression, no treatment is available that can fully cure or reverse atherosclerosis. Nanomedicine, which is the application of nanotechnology in medicine, is an emerging field in the treatment of many pathologies, including CVDs. It enables the production of drugs that interact with cellular receptors, and allows for controlling cellular processes after entering these cells. Nanomedicine aims to repair, control and monitor biological and physiological systems via nanoparticles (NPs), which have been shown to be efficient drug carriers. In this review we will, after a general introduction, highlight the advantages and limitations of the use of such nano-based medicine, the potential applications and targeting strategies via NPs. For example, we will provide a detailed discussion on NPs that can target relevant cellular receptors, such as integrins, or cellular processes related to atherogenesis, such as vascular smooth muscle cell proliferation. Furthermore, we will underline the (ongoing) clinical trials focusing on NPs in CVDs, which might bring new insights into this research field.

Nanomedicine for the treatment of diabetes-associated cardiovascular diseases and fibrosis

Cardiomyopathy and fibrosis are the main causes of heart failure in diabetes patients. For therapeutic purposes, a delivery system is required to enhance antidiabetic drug efficacy and specifically target profibrotic pathways in cardiomyocytes. Nanoparticles (NPs) have distinct advantages, including biocompatibility, bioavailability, targeting efficiency, and minimal toxicity, which make them ideal for antidiabetic treatment. In this review, we overview the latest information on the pathogenesis of cardiomyopathy and fibrosis in diabetes patients. We summarize how NP applications improve insulin and liraglutide efficacy and their sustained release upon oral administration. We provide a comprehensive review of the results of NP clinical trials in diabetes patients and of animal studies investigating the effects of NP-mediated anti-fibrotic treatments. Collectively, the application of advanced NP delivery systems in the treatment of cardiomyopathy and fibrosis in diabetes patients is a promising and innovative therapeutic strategy.

The Safety of Paclitaxel-Coated Devices for Patients with Peripheral Artery Disease

PURPOSE OF REVIEW

Peripheral artery disease (PAD) is a common, debilitating disease that impacts 8.5 million Americans and carries a poor prognosis. The most common manifestation of lower extremity PAD is claudication-a condition which significantly reduces quality of life and functional status. Paclitaxel-coated balloons and stents (PCBs and PESs) represented a breakthrough in the ability to treat medication-refractory patients relative to bare metal stents (BMSs) and percutaneous transluminal angioplasty (PTA) because they improve primary patency rates, reduce target lesion revascularization (TLR), and minimize late-lumen loss for femoropopliteal lesions. As a result, paclitaxel-coated devices (PCDs) were swiftly established as the standard of care for revascularization of femoropopliteal artery disease. A recent meta-analysis of summary-level data demonstrated a late mortality signal for patients treated with paclitaxel-coated devices relative to uncoated devices. This has had a major impact on the vascular community and for the treatment of patients with PAD. Herein, we provide a detailed review of the available data on the late mortality signal associated with paclitaxel.

RECENT FINDINGS

In December of 2018, Katsanos et al. J Am Heart Assoc 7: e011245, 2018) published data from randomized-controlled trials (RCTs) that demonstrated an increase in mortality at 2 and 5 years in patients treated with PCDs involving the femoropopliteal arterial segment relative to patients treated with uncoated devices. As a result of this analysis, randomized trials were stopped and the FDA sent a letter to healthcare providers recommending restriction of use of these devices to patients at the highest risk of restenosis. As additional data emerged supporting the safety of these devices, the FDA organized an advisory committee meeting to review the available data and to determine a pathway forward. The FDA concluded that there were insufficient data to make a final decision regarding the safety of PCDs. They allowed these devices to remain on the market, but with revised safety labeling and updated their letter to healthcare providers to continue to restrict use to patients at highest risk of reintervention. The FDA also called for additional long-term data, including from RCTs and real-world data. To date, an updated patient-level meta-analysis of clinical trial data, RCTs with longer-term follow-up, and large observational studies have been conducted. While meta-analyses conducted using overlapping clinical trial data have found a persistent increase in mortality for those treated with PCDs, individual industry-sponsored RCTs and large observational studies have consistently failed to detect a corresponding mortality increase. To date, no mechanism linking paclitaxel to mortality has been observed. We are currently at an impasse for drawing definitive conclusions regarding the long-term safety of paclitaxel-coated devices. As we await enrollment in ongoing clinical trials, we must proceed with making reasonable decisions for our patients' care from the available data, as these devices have important clinical implications for our patients. A critical lesson that can be learned from this controversy is that, for future device trials, committing to long-term follow-up is crucial.

Nanoparticle-Mediated Drug Delivery for the Treatment of Cardiovascular Diseases

Cardiovascular diseases (CVDs) are one of the foremost causes of high morbidity and mortality globally. Preventive, diagnostic, and treatment measures available for CVDs are not very useful, which demands promising alternative methods. Nanoscience and nanotechnology open a new window in the area of CVDs with an opportunity to achieve effective treatment, better prognosis, and less adverse effects on non-target tissues. The application of nanoparticles and nanocarriers in the area of cardiology has gathered much attention due to the properties such as passive and active targeting to the cardiac tissues, improved target specificity, and sensitivity. It has reported that more than 50% of CVDs can be treated effectively through the use of nanotechnology. The main goal of this review is to explore the recent advancements in nanoparticle-based cardiovascular drug carriers. This review also summarizes the difficulties associated with the conventional treatment modalities in comparison to the nanomedicine for CVDs.

Paclitaxel-Based Devices for the Treatment of PAD: Balancing Clinical Efficacy with Possible Risk

PURPOSE OF REVIEW

Paclitaxel-based endovascular devices have become the standard of care in symptomatic, medication-refractory peripheral artery disease (PAD) and in critical limb ischemia (CLI). This review examines the data on the efficacy and safety of these devices relative to standard balloon angioplasty (PTA) and bare metal stents (BMS).

RECENT FINDINGS

Randomized controlled trials (RCTs) have found that peripheral devices coated with paclitaxel result in superior patency rates and decreased target lesion revascularization (TLR) compared with non-drug-coated devices. Recently, a meta-analysis of randomized controlled trials unexpectedly reported an increase in mortality in patients treated with paclitaxel-coated devices (PCDs), resulting in the pausing of ongoing trials and a warning of safety from the FDA. Observational data that has been published since this time has not supported this safety concern. PAD is a common disease that severely impacts quality and length of life. PCDs are a promising therapy for patients with PAD, offering a more effective and durable intervention when compared with traditional PTA/BMS. A meta-analysis of RCTs identified a signal of harm with these devices which has now been replicated by the FDA. However, there is significant missing data from the trials analyzed by the meta-analysis and FDA, no plausible mechanism linking paclitaxel to death, and no correlation between paclitaxel dose and mortality. Analyses in observational data have found no safety signal. An FDA panel evaluating the validity of this late-mortality signal recently adjourned, emphasizing that the available data is incomplete. PCDs will remain on the market, and an active discussion is underway for developing an approach for improved post-market surveillance, device-labeling, and cause of death adjudication.

Nanoparticle Therapy for Vascular Diseases

Nanoparticles promise to advance strategies to treat vascular disease. Since being harnessed by the cancer field to deliver safer and more effective chemotherapeutics, nanoparticles have been translated into applications for cardiovascular disease. Systemic exposure and drug-drug interactions remain a concern for nearly all cardiovascular therapies, including statins, antithrombotic, and thrombolytic agents. Moreover, off-target effects and poor bioavailability have limited the development of completely new approaches to treat vascular disease. Through the rational design of nanoparticles, nano-based delivery systems enable more efficient delivery of a drug to its therapeutic target or even directly to the diseased site, overcoming biological barriers and enhancing a drug's therapeutic index. In addition, advances in molecular imaging have led to the development of theranostic nanoparticles that may simultaneously act as carriers of both therapeutic and imaging payloads. The following is a summary of nanoparticle therapy for atherosclerosis, thrombosis, and restenosis and an overview of recent major advances in the targeted treatment of vascular disease.

Cardiovascular therapies utilizing targeted delivery of nanomedicines and aptamers

Cardiovascular ailments are the foremost trigger of death in the world today, including myocardial infarction and ischemic heart diseases. To date, extraordinary measures have been prescribed, from the perspectives of both conventional medical therapies and surgeries, to enforce cardiac cell regeneration post cardiac traumas, albeit with limited long-term success. The prospects of successful heart transplants are also grim, considering exorbitant costs and unavailability of suitable donors in most cases. From the perspective of cardiac revascularization, use of nanoparticles and nanoparticle mediated targeted drug delivery have garnered substantial attention, attributing to both active and passive heart targeting, with enhanced target specificity and sensitivity. This review focuses on this aspect, while outlining the progress in targeted delivery of nanomedicines in the prognosis and subsequent therapy of cardiovascular disorders, and recapitulating the benefits and intrinsic challenges associated with the incorporation of nanoparticles. This article categorically provides an overview of nanoparticle-mediated targeted delivery systems and their implications in handling cardiovascular diseases, including their intrinsic benefits and encountered procedural trials and challenges. Additionally, the solicitations of aptamers in targeted drug delivery with identical objectives, are presented. This includes a detailed appraisal on various aptamer-navigated nanoparticle targeted delivery platforms in the diagnosis and treatment of cardiovascular maladies. Despite a few impending challenges, subject to additional investigations, both nanoparticles as well as aptamers show a high degree of promise, and pose as the next generation of drug delivery vehicles, in targeted cardiovascular therapy.

Coating and Pharmacokinetic Evaluation of Air Spray Coated Drug Coated Balloons

Drug coated balloons (DCB) are becoming the standard-care treatment for peripheral arterial disease (PAD). DCB use excipients to transfer and retain anti-proliferative drugs, such as paclitaxel. Excipients thus play a vital role in the design and function of DCB, however methods to coat balloons with excipients and anti-proliferative drugs remain unknown. The goal of this study was to thus develop an approach to coat and evaluate DCB for various excipients. An air sprayer method was developed to deposit paclitaxel and various excipients onto non-coated commercially available angioplasty balloons. The coating of the angioplasty balloons was evaluated for drug deposition and coating efficiency using high performance liquid chromatography tandem mass spectrometry. Drug transfer and retention of the coated angioplasty balloons into arterial segments were evaluated ex vivo using harvested pig arteries in a pulsatile flow bioreactor. The air sprayer method successfully delivered varying excipients including bovine serum albumin (BSA), urea and iohexol. The air spray method was configured to coat four angioplasty balloons simultaneously with paclitaxel and iohexol with an average paclitaxel load of 4.0 ± 0.70 µg/mm². The intra-day (within) and inter-day (between) coating precisions, defined as relative standard deviation (RSD), was 17.2 and 15.5%, respectively. Ex vivo deployment of iohexol-paclitaxel DCB yielded an arterial paclitaxel concentration of 123.4 ± 44.68 ng/mg (n = 3) at 1 h, 126.7 ± 25.27 ng/mg (n = 3) at 1 day, and 12.9 ± 12.88 ng/mg (n = 3) at 7 days. This work provides proof-of-concept of a quick, inexpensive approach to coat commercially available angioplasty balloons with paclitaxel and various excipients.

Recent Advances in Treatment of Coronary Artery Disease: Role of Science and Technology

Coronary artery disease (CAD) is one of the most common causes of death worldwide. In the last decade, significant advancements in CAD treatment have been made. The existing treatment is medical, surgical or a combination of both depending on the extent, severity and clinical presentation of CAD. The collaboration between different science disciplines such as biotechnology and tissue engineering has led to the development of novel therapeutic strategies such as stem cells, nanotechnology, robotic surgery and other advancements (3-D printing and drugs). These treatment modalities show promising effects in managing CAD and associated conditions. Research on stem cells focuses on studying the potential for cardiac regeneration, while nanotechnology research investigates nano-drug delivery and percutaneous coronary interventions including stent modifications and coatings. This article aims to provide an update on the literature (in vitro, translational, animal and clinical) related to these novel strategies and to elucidate the rationale behind their potential treatment of CAD. Through the extensive and continued efforts of researchers and clinicians worldwide, these novel strategies hold the promise to be effective alternatives to existing treatment modalities.

Paclitaxel-Coated Balloon for Femoropopliteal Artery Disease

PURPOSE OF THE REVIEW

Percutaneous transluminal angioplasty is an established form of therapy for femoropopliteal artery disease. Currently, percutaneous transluminal angioplasty (PTA) is carried out using standard balloon with or without deployment of a stent but is associated with a high rate of restenosis and stent-related complications. Treatment options for restenosis, especially in-stent restenosis, are limited. Drug-coated balloons promise to reduce the rates of restenosis by effective delivery of antiproliferative agent (paclitaxel) directly to vessel wall without the need for a permanent implant. In this review, we look at the technology and rationale behind drug-coated balloons and examine the evidence available so far.

RECENT FINDINGS

Recently, several studies tested the effectiveness of paclitaxel-coated balloon angioplasty compared to that of standard PTA in both de novo lesions and in-stent restenosis of femoropopliteal artery. Paclitaxel-coated balloon use resulted in reduced rates of restenosis and favourable clinical outcomes in both these lesion groups. However, in complex lesions, there is still lack of data to support the use of these balloons. Paclitaxel-coated balloon is a safe and effective therapeutic option in patients with both de novo lesions and in-stent restenosis involving femoropopliteal artery. In light of the new evidence, it is time to consider incorporation of this effective therapeutic option into clinical practice. However, further research is needed for the use of paclitaxel-coated balloons in complex femoropopliteal lesions like calcified lesions especially as adjuncts to cutting balloons and debulking strategies.

Drug-eluting balloons for treatment of SFA and popliteal disease - A review of current status

The endovascular treatment of atherosclerotic disease of the infra-inguinal arteries has changed significantly over the last decades. In an attempt to overcome the high restenosis rates that characterize plain balloon angioplasty and stenting using bare mate stents drug-eluting balloon technology has been applied in the treatment of lesions of the superficial femoral and popliteal artery. This paper will give an overview of the rationale and the technology of drug-eluting balloons and will review currently available data from registries and randomized controlled trials.

Nanomedicine in coronary artery disease

Nanomedicine is one of the most promising therapeutic modalities researchers are working on. It involves development of drugs and devices that work at the nanoscale (10-9m). Coronary artery disease (CAD) is responsible for more than a third of all deaths in age group >35 years. With such a huge burden of mortality, CAD is one of the diseases where nanomedicine is being employed for preventive and therapeutic interventions. Nanomedicine can effectively deliver focused drug payload at sites of local plaque formation. Non-invasive strategies include thwarting angiogenesis, intra-arterial thrombosis and local inflammation. Invasive strategies following percutaneous coronary intervention (PCI) include anti-restenosis and healing enhancement. However, before practical application becomes widespread, many challenges need to be dealt with. These include manufacturing at the nanoscale, direct nanomaterial cellular toxicity and visualization.

[Drug-coated balloons in the treatment of peripheral artery disease (PAD). History and current level of evidence]

BACKGROUND

Despite initially encouraging technical success after femoropopliteal PTA, restenosis remains the major challenge in patients with peripheral artery disease (PAD). The main cause of restenosis is neointimal hyperplasia which can be suppressed by antiproliferative drugs. Drug-coated balloons (DCB) or drug-eluting stents (DES) are used for the inhibition of restenosis.

OBJECTIVES

The present article gives an overview of DCB development, actual DCB systems for femoro- and infrapopliteal use, displays the outcomes of randomized clinical trials and the discusses the evidence for the DCB treatment in PAD.

METHODS

A systematic literature search was performed in i) medical journals (i. e. MEDLINE), ii) in international registers for clinical studies (i. e. www.clinicaltrials.gov ) and in iii) scientific session abstracts.

RESULTS

The clinical evidence of the PTX-DCB of the first and following generation has been shown in several controlled randomized trials.

CONCLUSIONS

Major advantages of the DCBs lie in leaving no stent scaffold behind, the immediate release of high drug concentrations with a single dosage, their efficacy in areas, where stents have been contra-indicated until now and its use for secondary interventions. As their effect seems to be limited in severely calcified lesions, prior plaque preconditioning or removal could be advantageous. First positive results data supporting this hypothesis do exist.

Critical appraisal of paclitaxel balloon angioplasty for femoral-popliteal arterial disease

Peripheral arterial disease, particularly critical limb ischemia, is an area with urgent need for optimized therapies because, to date, vascular interventions often have limited life spans. In spite of initial encouraging technical success after femoropopliteal percutaneous transluminal angioplasty or stenting, postprocedural restenosis remains the major problem. The challenging idea behind the drug-coated balloon (DCB) concept is the biological modification of the injury response after balloon dilatation. Antiproliferative drugs administered via DCBs or drug-eluting stents are able to suppress neointimal hyperplasia, the main cause of restenosis. This article reviews the results of DCB treatments of femoropopliteal and infrapopliteal lesions in comparison to standard angioplasty with uncoated balloons. A systematic literature search was performed in 1) medical journals (ie, MEDLINE), 2) international registers for clinical studies (ie, www.clinicaltrials.gov), and 3) abstracts of scientific sessions. Several controlled randomized trials with follow-up periods of up to 5 years demonstrated the efficacy of paclitaxel –DCB technology. However, calcified lesions seem to affect the efficacy of DCB. Combinations of preconditioning methods with DCBs showed promising results. Although the mechanical abrasion of calcium via atherectomy or laser ablation showed favorable periprocedural results, the long-term impact on restenosis and clinical outcome has to be demonstrated. Major advantages of the DCBs are the rapid delivery of drug at uniform concentrations with a single dose, their efficacy in areas wherein stents have been contraindicated until now (ie, bifurcation, ostial lesions), and in leaving no stent scaffold behind. Reinterventions are easier to perform because DCBs leave no metal behind. Various combinations of DCBs with other treatment modalities may prove to be viable options in future. The follow-up results of clinical studies will evaluate the long-term impact of DCBs.

Coating of intravascular balloon with paclitaxel prevents constrictive remodeling of the dilated porcine femoral artery due to inhibition of intimal and media fibrosis

Here we investigated how a coating of intravascular balloon with paclitaxel (drug-coated balloon; DCB, Freeway™) impacted porcine peripheral artery vascular function and remodeling. Domestic swine (n = 54) underwent percutaneous overstretch balloon dilation of femoral and iliac arteries, controlled by angiography and optical coherence tomography (OCT). Paclitaxel tissue uptake was measured at 1 h and 1, 3, and 9 days post-dilation. At these time-points and at 32 ± 2 days, vascular function of the dilated arteries was assessed using the organ chamber model. Neointimal growth and remodeling indices were determined using OCT and histology at 32 ± 2 days. Intima and media fibrosis were quantified by picrosirius red staining. Post-inflation femoral artery tissue drug levels were 460 ± 214, 136 ± 123, 14 ± 6, and 0.1 ± 0.1 ng/mg at 1 h and 1, 3, and 9 days, respectively. Compared to plain balloon, Freeway™ resulted in a significantly smaller neointimal area (P < 0.05), less tunica intima (8.0 ± 5.4 vs 14.2 ± 4.7 %) and media fibrosis (15.6 ± 7.7 vs 24.5 ± 5.4 %), and less femoral artery constrictive remodeling (remodeling index: 1.08 ± 0.08 vs 0.94 ± 0.08). The DCB was associated with significantly increased vasoconstrictor tone and endothelium-dependent vasodilation impairment shortly after post-overstretch injury. Overall, DCB dilation of peripheral arteries resulted in high drug uptake into arterial tissue. Compared with the plain balloon, the DCB was associated with decreased vessel wall fibrosis after balloon overstretch injury, and reduced degrees of constrictive remodeling and neointimal hyperplasia.

Treatment of patients with aortic atherosclerotic disease with paclitaxel-associated lipid nanoparticles

OBJECTIVE

The toxicity of anti-cancer chemotherapeutic agents can be reduced by associating these compounds, such as the anti-proliferative agent paclitaxel, with a cholesterol-rich nanoemulsion (LDE) that mimics the lipid composition of low-density lipoprotein (LDL). When injected into circulation, the LDE concentrates the carried drugs in neoplastic tissues and atherosclerotic lesions. In rabbits, atherosclerotic lesion size was reduced by 65% following LDE-paclitaxel treatment. The current study aimed to test the effectiveness of LDE-paclitaxel on inpatients with aortic atherosclerosis.

METHODS

This study tested a 175 mg/m2 body surface area dose of LDE-paclitaxel (intravenous administration, 3/3 weeks for 6 cycles) in patients with aortic atherosclerosis who were aged between 69 and 86 yrs. A control group of 9 untreated patients with aortic atherosclerosis (72-83 yrs) was also observed.

RESULTS

The LDE-paclitaxel treatment elicited no important clinical or laboratory toxicities. Images were acquired via multiple detector computer tomography angiography (64-slice scanner) before treatment and at 1-2 months after treatment. The images showed that the mean plaque volume in the aortic artery wall was reduced in 4 of the 8 patients, while in 3 patients it remained unchanged and in one patient it increased. In the control group, images were acquired twice with an interval of 6-8 months. None of the patients in this group exhibited a reduction in plaque volume; in contrast, the plaque volume increased in three patients and remained stable in four patients. During the study period, one death unrelated to the treatment occurred in the LDE-paclitaxel group and one death occurred in the control group.

CONCLUSION

Treatment with LDE-paclitaxel was tolerated by patients with cardiovascular disease and showed the potential to reduce atherosclerotic lesion size.

Nanoparticle drug delivery systems and their use in cardiac tissue therapy

Cardiovascular diseases make up one of the main causes of death today, with myocardial infarction and ischemic heart disease contributing a large share of the deaths reported. With mainstream clinical therapy focusing on palliative medicine following myocardial infarction, the structural changes that occur in the diseased heart will eventually lead to end-stage heart failure. Heart transplantation remains the only gold standard of cure but a shortage in donor organs pose a major problem that led to clinicians and researchers looking into alternative strategies for cardiac repair. This review will examine some alternative methods of treatment using chemokines and drugs carried by nanoparticles as drug delivering agents for the purposes of treating myocardial infarction through the promotion of revascularization. We will also provide an overview of existing studies involving such nanoparticulate drug delivery systems, their reported efficacy and the challenges facing their translation into ubiquitous clinical use.

Local delivery of paclitaxel in the treatment of peripheral arterial disease

BACKGROUND

Despite advancements from balloon angioplasty to drug-eluting stents, primary patency rates after endovascular revascularization of peripheral artery disease have remained inferior compared to surgery. Endovascular revascularization has been limited by restenosis and mechanical stent failure. Thus, there is increased research into other nonstent-based local drug delivery modalities, which can provide an active drug to inhibit restenosis focally and avoid the risk of systemic adverse effects.

METHODS

This review will summarize the unique properties of paclitaxel and studies on paclitaxel local delivery for the treatment of peripheral artery disease. A MEDLINE search for relevant peer-reviewed scientific literature published in English was conducted. Search terms included but were not limited to paclitaxel pharmacodynamics, paclitaxel local drug delivery, and drug eluting balloons, with a focus on the use of paclitaxel in the context of coronary and peripheral vascular disease.

RESULTS

The primary search produced 182 results of which 51 papers were relevant. Of the 51 relevant papers, 27 were original research papers and 24 were either review papers, commentary or opinion papers.

CONCLUSIONS

Paclitaxel has several chemical properties, which make it ideal for local drug delivery including its hydrophobicity, ability to concentrate into the arterial intima layer and prolonged effect on cells even after brief exposure periods. Local delivery of paclitaxel via injection catheters, balloon catheters and coated balloons has shown encouraging results in terms of efficacy and safety in small-scale animal and clinical studies. Additional preclinical and clinical studies are needed to determine the long-term efficacy and safety of these treatments in humans.

Sustained release of milrinone delivered via microparticles in a rodent model of myocardial infarction

OBJECTIVE

The aim of the present study was to construct a new drug delivery system for milrinone using microparticles. This novel technology enhances drug bioavailability and decreases toxicity, with future implications for the treatment of end-stage heart failure.

METHODS

Polylactic-co-glycolic acid microparticles (PLGA-MPs) loaded with milrinone were prepared using a double emulsion-solvent evaporation technique. In vitro release kinetics was evaluated at physiologic conditions. A total of 24 female Lewis rats underwent left coronary artery ligation. One week after ligation, all rats were randomized to 1 of 3 groups (n=8 per group). Group I received an intravenous injection of PLGA-MPs alone; group II, a bolus intravenous injection of milrinone; and group III an intravenous injection of milrinone-PLGA-MPs. All injections were administrated slowly by way of the tail vein over 10 minutes. Transthoracic echocardiography, noninvasive heart rate monitoring, and blood pressure measurements were performed at different predetermined intervals before and for 24 hours after the injection. All rats survived for 24 hours and were then killed by euthanasia. Serum plasma was taken for cytokine assays and determination of milrinone levels using high-performance liquid chromatography.

RESULTS

Group III had a significantly greater left ventricular ejection fraction at 90 minutes and 3, 6, and 12 hours after treatment compared with the other groups. The milrinone plasma level was significantly greater in group III than in the other groups (group I, 0 ng/mL; group II, 1.7±2.4 ng/mL; group III, 9.1±2.2 ng/mL; P<.05). The intercellular adhesion molecule and cytokine-induced neutrophil chemoattractant-1 levels were significantly lower in group III than in the other 2 groups (P<.05).

CONCLUSIONS

Drug encapsulation using microparticles can prolong the effects of milrinone. We propose a new strategy for future drug delivery in patients with end-stage heart failure.

Nanomedicine-based strategies for treatment of atherosclerosis

Atherosclerosis is a chronic inflammatory disease of the arterial wall that arises from an imbalanced lipid metabolism and a maladaptive inflammatory response. Despite intensive research on mechanisms underlying atherosclerotic lesion formation and progression during the past decade, translation of this knowledge into the clinic is scarce. Although developments have primarily been made in the area of antitumor therapy, recent advances have shown the potential of nanomedicine-based treatment strategies for atherosclerosis. Here we describe the features of currently available nanomedical formulations that have been optimized for atherosclerosis treatment, and we further describe how they can be instructed to target inflammatory processes in the arterial wall. Despite their limitations, nanomedical applications might hold promise for personalized medicine, and further efforts are needed to improve atherosclerosis-specific targeting.

Nanoparticle drug- and gene-eluting stents for the prevention and treatment of coronary restenosis

Percutaneous coronary intervention (PCI) has become the most common revascularization procedure for coronary artery disease. The use of stents has reduced the rate of restenosis by preventing elastic recoil and negative remodeling. However, in-stent restenosis remains one of the major drawbacks of this procedure. Drug-eluting stents (DESs) have proven to be effective in reducing the risk of late restenosis, but the use of currently marketed DESs presents safety concerns, including the non-specificity of therapeutics, incomplete endothelialization leading to late thrombosis, the need for long-term anti-platelet agents, and local hypersensitivity to polymer delivery matrices. In addition, the current DESs lack the capacity for adjustment of the drug dose and release kinetics appropriate to the disease status of the treated vessel. The development of efficacious therapeutic strategies to prevent and inhibit restenosis after PCI is critical for the treatment of coronary artery disease. The administration of drugs using biodegradable polymer nanoparticles as carriers has generated immense interest due to their excellent biocompatibility and ability to facilitate prolonged drug release. Despite the potential benefits of nanoparticles as smart drug delivery and diagnostic systems, much research is still required to evaluate potential toxicity issues related to the chemical properties of nanoparticle materials, as well as to their size and shape. This review describes the molecular mechanism of coronary restenosis, the use of DESs, and progress in nanoparticle drug- or gene-eluting stents for the prevention and treatment of coronary restenosis.

Cardiovascular therapy through nanotechnology – how far are we still from bedside?

Recent years brought about a widespread interest in the potential applications of nanotechnology for the diagnostics and the therapy of human diseases. With its promise of disease-targeted, patient-tailored treatment and reduced side effects, nanomedicine brings hope for millions of patients suffering of non-communicable diseases such as cancer or cardiovascular disorders. However, the emergence of the complex, multicomponent products based on new technologies poses multiple challenges to successful approval in clinical practice. Regulatory and development considerations, including properties of the components, reproducible manufacturing and appropriate characterization methods, as well as nanodrugs’ safety and efficacy are critical for rapid marketing of the new products. This review discusses the recent advances in cardiovascular applications of nanotechnologies and highlights the challenges that must be overcome in order to fill the gap existing between the promising bench trials and the successful bedside applications.

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.

Local drug delivery to prevent restenosis

INTRODUCTION

Despite significant advances in vascular biology, bioengineering, and pharmacology, restenosis remains a limitation to the overall efficacy of vascular reconstructions, both percutaneous and open. Although the pathophysiology of intimal hyperplasia is complex, a number of drugs and molecular tools have been identified that can prevent restenosis. Moreover, the focal nature of this process lends itself to treatment with local drug administration. This article provides a broad overview of current and future techniques for local drug delivery that have been developed to prevent restenosis after vascular interventions.

METHODS

A systematic electronic literature search using PubMed was performed for all accessible published articles through September 2012. In an effort to remain current, additional searches were performed for abstracts presented at relevant societal meetings, filed patents, clinical trials, and funded National Institutes of Health awards.

RESULTS

The efficacy of local drug delivery has been demonstrated in the coronary circulation with the current clinical use of drug-eluting stents. Until recently, however, drug-eluting stents were not found to be efficacious in the peripheral circulation. Further pursuit of intraluminal devices has led to the development of balloon-based technologies, with a recent surge in trials involving drug-eluting balloons. Early data appear encouraging, particularly for treatment of superficial femoral artery lesions, and several devices have recently received the Conformité Européene mark in Europe. Investigators have also explored the periadventitial application of biomaterials containing antirestenotic drugs, an approach that could be particularly useful for surgical bypass or endarterectomy. In the past, systemic drug delivery has been unsuccessful; however, there has been recent exploration of intravenous delivery of drugs designed specifically to target injured or reconstructed arteries. Our review revealed a multitude of additional interesting strategies, including >65 new patents issued during the past 2 years for approaches to local drug delivery focused on preventing restenosis.

CONCLUSIONS

Restenosis after intraluminal or open vascular reconstruction remains an important clinical problem. Success in the coronary circulation has not translated into solutions for the peripheral arteries. However, our literature review reveals a number of promising approaches, including drug-eluting balloons, periadventitial drug delivery, and targeted systemic therapies. These and other innovations suggest that the future is bright and that a solution for preventing restenosis in peripheral vessels will soon be at hand.

Strategies to address low drug solubility in discovery and development

Drugs with low water solubility are predisposed to low and variable oral bioavailability and, therefore, to variability in clinical response. Despite significant efforts to "design in" acceptable developability properties (including aqueous solubility) during lead optimization, approximately 40% of currently marketed compounds and most current drug development candidates remain poorly water-soluble. The fact that so many drug candidates of this type are advanced into development and clinical assessment is testament to an increasingly sophisticated understanding of the approaches that can be taken to promote apparent solubility in the gastrointestinal tract and to support drug exposure after oral administration. Here we provide a detailed commentary on the major challenges to the progression of a poorly water-soluble lead or development candidate and review the approaches and strategies that can be taken to facilitate compound progression. In particular, we address the fundamental principles that underpin the use of strategies, including pH adjustment and salt-form selection, polymorphs, cocrystals, cosolvents, surfactants, cyclodextrins, particle size reduction, amorphous solid dispersions, and lipid-based formulations. In each case, the theoretical basis for utility is described along with a detailed review of recent advances in the field. The article provides an integrated and contemporary discussion of current approaches to solubility and dissolution enhancement but has been deliberately structured as a series of stand-alone sections to allow also directed access to a specific technology (e.g., solid dispersions, lipid-based formulations, or salt forms) where required.

The physiology of cardiovascular disease and innovative liposomal platforms for therapy

Heart disease remains the major cause of death in males and females, emphasizing the need for novel strategies to improve patient treatment and survival. A therapeutic approach, still in its infancy, is the development of site-specific drug-delivery systems. Nanoparticle-based delivery systems, such as liposomes, have evolved into robust platforms for site-specific delivery of therapeutics. In this review, the clinical impact of cardiovascular disease and the pathophysiology of different subsets of the disease are described. Potential pathological targets for therapy are introduced, and promising advances in nanotherapeutic cardiovascular applications involving liposomal platforms are presented.

Nanocarriers for tracking and treating diseases

Site directed drug delivery with high efficacy is the biggest challenge in the area of current pharmaceuticals. Biodegradable polymer-based controlled release nanoparticle platforms could be beneficial for targeted delivery of therapeutics and contrast agents for a myriad of important human diseases. Biodegradable nanoparticles, which can be engineered to load multiple drugs with varied physicochemical properties, contrast agents, and cellular or intracellular component targeting moieties, have emerged as potential alternatives for tracking and treating human diseases. In this review, we will highlight the current advances in the design and execution of such platforms for their potential application in the diagnosis and treatment of variety of diseases ranging from cancer to Alzheimer's and we will provide a critical analysis of the associated challenges for their possible clinical translation.

Advances in nanotechnology for the management of coronary artery disease

Nanotechnology holds tremendous potential to advance the current treatment of coronary artery disease. Nanotechnology may assist medical therapies by providing a safe and efficacious delivery platform for a variety of drugs aimed at modulating lipid disorders, decreasing inflammation and angiogenesis within atherosclerotic plaques, and preventing plaque thrombosis. Nanotechnology may improve coronary stent applications by promoting endothelial recovery on a stent surface utilizing bio-mimetic nanofibrous scaffolds, and also by preventing in-stent restenosis using nanoparticle-based delivery of drugs that are decoupled from stents. Additionally, nanotechnology may enhance tissue-engineered graft materials for application in coronary artery bypass grafting by facilitating cellular infiltration and remodeling of a graft matrix.

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.

Nanotechnology and human health: risks and benefits

Nanotechnology is expected to be promising in many fields of medical applications, mainly in cancer treatment. While a large number of very attractive exploitations open up for the clinics, regulatory agencies are very careful in admitting new nanomaterials for human use because of their potential toxicity. The very active research on new nanomaterials that are potentially useful in medicine has not been counterbalanced by an adequate knowledge of their pharmacokinetics and toxicity. The different nanocarriers used to transport and release the active molecules to the target tissues should be treated as additives, with potential side effects of themselves or by virtue of their dissolution or aggregation inside the body. Only recently has a systematic classification of nanomaterials been proposed, posing the basis for dedicated modeling at the nanoscale level. The use of in silico methods, such as nano-QSAR and PSAR, while highly desirable to expedite and rationalize the following stages of toxicological research, are not an alternative, but an introduction to mandatory experimental work.

Drug-eluting stents

Coronary artery disease (CAD) is currently a leading cause of death worldwide. Drug-eluting stents (DESs) have been dominant for the treatment of CAD in the interventional cardiology world owing to their efficacy in significantly reducing restenosis. However, late stage stent thrombosis has become a major concern. Stent platform, drug delivery vehicle and type of drug are three parts of DES and each part affects the performance of the DES. Aiming to provide a clue for the design of future DES, this review focuses on the development of the three major components of DES and their roles in restenosis and thrombosis.

Biodegradable Sirolimus-loaded Poly(lactide) Nanoparticles as Drug Delivery System for the Prevention of In-Stent Restenosis in Coronary Stent Application

The administration of drugs using biodegradable polymer nanoparticles as carriers has generated immense interest due to their excellent biocompatibility and the prolonged drug release. The scope of this work was to determine the applicability of sirolimus-loaded biodegradable poly(D,L-lactide) (PDLLA) nanoparticles as drug carriers to prevent restenotic processes after stent implantation. The average 250 nm sized 20%(w/w) sirolimus-loaded nanoparticles were extensively characterized with regard to in vitro degradation, biocompatibility and in vitro drug release. The particles show biphasic release kinetics consisting of a short burst release of 50%(w/w) sirolimus payload, followed by a longer, slower release phase, which are desirable for the application as a drug delivery carrier. All presented results exhibit the potential of sirolimus-loaded PDLLA nanoparticles as promising local and sustained drug delivery systems administered intraluminally to reduce in-stent restenosis after stent implantation.