Hydroxyapatite-binding micelles for the detection of vascular calcification in atherosclerosis

Organic Nanoparticles in Progressing Cardiovascular Disease Treatment and Diagnosis

Cardiovascular diseases (CVDs), the world's most prominent cause of mortality, continue to be challenging conditions for patients, physicians, and researchers alike. CVDs comprise a wide range of illnesses affecting the heart, blood vessels, and the blood that flows through and between them. Advances in nanomedicine, a discipline focused on improving patient outcomes through revolutionary treatments, imaging agents, and ex vivo diagnostics, have created enthusiasm for overcoming limitations in CVDs' therapeutic and diagnostic landscapes. Nanomedicine can be involved in clinical purposes for CVD through the augmentation of cardiac or heart-related biomaterials, which can be functionally, mechanically, immunologically, and electrically improved by incorporating nanomaterials; vasculature applications, which involve systemically injected nanotherapeutics and imaging nanodiagnostics, nano-enabled biomaterials, or tissue-nanoengineered solutions; and enhancement of sensitivity and/or specificity of ex vivo diagnostic devices for patient samples. Therefore, this review discusses the latest studies based on applying organic nanoparticles in cardiovascular illness, including drug-conjugated polymers, lipid nanoparticles, and micelles. Following the revised information, it can be concluded that organic nanoparticles may be the most appropriate type of treatment for cardiovascular diseases due to their biocompatibility and capacity to integrate various drugs.

Recent advancements in nanotechnology based drug delivery for the management of cardiovascular disease

Cardiovascular diseases (CVDs) constitute a predominant cause of both global mortality and morbidity. To address the challenges in the early diagnosis and management of CVDs, there is growing interest in the field of nanotechnology and nanomaterials to develop innovative diagnostic and therapeutic approaches. This review focuses on the recent advancements in nanotechnology-based diagnostic techniques, including cardiac immunoassays (CIA), cardiac circulating biomarkers, cardiac exosomal biomarkers, and molecular Imaging (MOI). Moreover, the article delves into the exciting developments in nanoparticles (NPs), biomimetic NPs, nanofibers, nanogels, and nanopatchs for cardiovascular applications. And discuss how these nanoscale technologies can improve the precision, sensitivity, and speed of CVD diagnosis and management. While highlighting their vast potential, we also address the limitations and challenges that must be overcome to harness these innovations successfully. Furthermore, this review focuses on the emerging opportunities for personalized and effective cardiovascular care through the integration of nanotechnology, ultimately aiming to reduce the global burden of CVDs.

Navigating the landscape: Prospects and hurdles in targeting vascular smooth muscle cells for atherosclerosis diagnosis and therapy

Vascular smooth muscle cells (VSMCs) have emerged as pivotal contributors throughout all phases of atherosclerotic plaque development, effectively dispelling prior underestimations of their prevalence and significance. Recent lineage tracing studies have unveiled the clonal nature and remarkable adaptability inherent to VSMCs, thereby illuminating their intricate and multifaceted roles in the context of atherosclerosis. This comprehensive review provides an in-depth exploration of the intricate mechanisms and distinctive characteristics that define VSMCs across various physiological processes, firmly underscoring their paramount importance in shaping the course of atherosclerosis. Furthermore, this review offers a thorough examination of the significant strides made over the past two decades in advancing imaging techniques and therapeutic strategies with a precise focus on targeting VSMCs within atherosclerotic plaques, notably spotlighting meticulously engineered nanoparticles as a promising avenue. We envision the potential of VSMC-targeted nanoparticles, thoughtfully loaded with medications or combination therapies, to effectively mitigate pro-atherogenic VSMC processes. These advancements are poised to contribute significantly to the pivotal objective of modulating VSMC phenotypes and enhancing plaque stability. Moreover, our paper also delves into recent breakthroughs in VSMC-targeted imaging technologies, showcasing their remarkable precision in locating microcalcifications, dynamically monitoring plaque fibrous cap integrity, and assessing the therapeutic efficacy of medical interventions. Lastly, we conscientiously explore the opportunities and challenges inherent in this innovative approach, providing a holistic perspective on the potential of VSMC-targeted strategies in the evolving landscape of atherosclerosis research and treatment.

Biomimetic Grapefruit-Derived Extracellular Vesicles for Safe and Targeted Delivery of Sodium Thiosulfate against Vascular Calcification

As the prevalence of vascular calcification (VC), a strong contributor to cardiovascular morbidity and mortality, continues to increase, the need for pharmacologic therapies becomes urgent. Sodium thiosulfate (STS) is a clinically approved drug for therapy against VC; however, its efficacy is hampered by poor bioavailability and severe adverse effects. Plant-derived extracellular vesicles have provided options for VC treatment since they can be used as biomimetic drug carriers with higher biosafety and targeting abilities than artificial carriers. Inspired by natural grapefruit-derived extracellular vesicles (EVs), we fabricated a biomimetic nanocarrier comprising EVs loaded with STS and further modified with hydroxyapatite crystal binding peptide (ESTP) for VC-targeted delivery of STS. In vitro, the ESTP nanodrug exhibited excellent cellular uptake capacity by calcified vascular smooth muscle cells (VSMCs) and subsequently inhibited VSMCs calcification. In the VC mice model, the ESTP nanodrug showed preferentially the highest accumulation in the calcified arteries compared to other treatment groups. Mechanistically, the ESTP nanodrug significantly prevented VC via driving M2 macrophage polarization, reducing inflammation, and suppressing bone-vascular axis as demonstrated by inhibiting osteogenic phenotype trans-differentiation of VSMCs while enhancing bone quality. In addition, the ESTP nanodrug did not induce hemolysis or cause any damage to other organs. These results suggest that the ESTP nanodrug can prove to be a promising agent against VC without the concern of systemic toxicity.

Long-term, in vivo therapeutic effects of a single dose of miR-145 micelles for atherosclerosis

Atherosclerosis is a chronic inflammatory disease that is characterized by the build-up of lipid-rich plaques in the arterial walls. The standard treatment for patients with atherosclerosis is statin therapy aimed to lower serum lipid levels. Despite its widespread use, many patients taking statins continue to experience acute events. Thus, to develop improved and alternative therapies, we previously reported on microRNA-145 (miR-145 micelles) and its ability to inhibit atherosclerosis by targeting vascular smooth muscle cells (VSMCs). Importantly, one dose of miR-145 micelles significantly abrogated disease progression when evaluated two weeks post-administration. Thus, in this study, to evaluate how long the sustained effects of miR-145 micelles can be maintained and towards identifying a dosing regimen that is practical for patients with chronic disease, the therapeutic effects of a single dose of miR-145 micelles were evaluated for up to two months in vivo. After one and two months post-treatment, miR-145 micelles were found to reduce plaque size and overall lesion area compared to all other controls including statins without causing adverse effects. Furthermore, a single dose of miR-145 micelle treatment inhibited VSMC transdifferentiation into pathogenic macrophage-like and osteogenic cells in plaques. Together, our data shows the long-term efficacy and sustained effects of miR-145 micelles that is amenable using a dosing frequency relevant to chronic disease patients.

Nanomedicines for cardiovascular disease

The leading cause of death in the world, cardiovascular disease (CVD), remains a formidable condition for researchers, clinicians and patients alike. CVD comprises a broad collection of diseases spanning the heart, the vasculature and the blood that runs through and interconnects them. Limitations in CVD therapeutic and diagnostic landscapes have generated excitement for advances in nanomedicine, a field focused on improving patient outcomes through transformative therapies, imaging agents and ex vivo diagnostics. CVD nanomedicines are fundamentally shaped by their intended clinical application, including (1) cardiac or heart-related biomaterials, which can be functionally (for example, mechanically, immunologically, electrically) improved by incorporating nanomaterials; (2) the vasculature, involving systemically injected nanotherapeutics and imaging nanodiagnostics, nano-enabled biomaterials or tissue-nanoengineered solutions; and (3) improving the sensitivity and/or specificity of ex vivo diagnostic devices for patient samples. While immunotherapy has developed into a key pillar of oncology in the past dozen years, CVD immunotherapy and immunoimaging are recently emergent and likely to factor substantially in CVD management in the coming decade. The nanomaterials in CVD-related clinical trials and many promising preclinical strategies indicate that nanomedicine is on the cusp of greatly impacting patients with CVD. Here we review these recent advances, highlighting key clinical opportunities in the rapidly emerging field of CVD nanomedicine.

A Non-Invasive Method for Monitoring Osteogenesis and Osseointegration Using Near-Infrared Fluorescent Imaging: A Model of Maxilla Implantation in Rats

Currently, computed tomography and conventional X-ray radiography usually generate a micro-artifact around metal implants. This metal artifact frequently causes false positive or negative diagnoses of bone maturation or pathological peri-implantitis around implants. In an attempt to repair the artifacts, a highly specific nanoprobe, an osteogenic biomarker, and nano-Au-Pamidronate were designed to monitor the osteogenesis. In total, 12 Sprague Dawley rats were included in the study and could be chategorized in 3 groups: 4 rats in the X-ray and CT group, 4 rats in the NIRF group, and 4 rats in the sham group. A titanium alloy screw was implanted in the anterior hard palate. The X-ray, CT, and NIRF images were taken 28 days after implantation. The X-ray showed that the tissue surrounded the implant tightly; however, a gap of metal artifacts was noted around the interface between dental implants and palatal bone. Compared to the CT image, a fluorescence image was noted around the implant site in the NIRF group. Furthermore, the histological implant-bone tissue also exhibited a significant NIRF signal. In conclusion, this novel NIRF molecular imaging system precisely identifies the image loss caused by metal artifacts and can be applied to monitoring bone maturation around orthopedic implants. In addition, by observing the new bone formation, a new principle and timetable for an implant osseointegrated with bone can be established and a new type of implant fixture or surface treatment can be evaluated using this system.

CircHIPK3 Regulates Vascular Smooth Muscle Cell Calcification Via the miR-106a-5p/MFN2 Axis

Atherosclerosis is the most common arterial disease and is closely related to vascular calcification. CircHIPK3 has been implicated in atherosclerosis development, but the possible downstream regulatory mechanisms remain unclear. The levels of circHIPK3, miR-106a and MFN2 in tissues and blood samples of patients with atherosclerosis were detected by RT-qPCR. The levels of circHIPK3, miR-106a and MFN2 were detected by RT-qPCR and the expression levels of MFN2, osteogenic and cartilage differentiation marker proteins were detected by western blot in vitro. ALP staining, Alizarin Red staining, and calcium content detection evaluated the degree of osteogenic differentiation of cells. Alcian blue staining detected the level of cell cartilage differentiation. Luciferase detected the targeting relationship between circHIPK3 and miR-106a-5p, as well as miR-106a-5p and MFN2. CircHIPK3 and MFN2 were low expressed and miR-106a-5p was highly expressed in tissues and blood samples of patients with atherosclerosis, as well as vascular smooth muscle cell (VSMC) with osteogenic and cartilage differentiation. Overexpression of circHIPK3 reduced the cell mineralization and calcium content. Overexpression of circHIPK3 inhibited osteogenic differentiation by decreasing ALP activity, RUNX2, and OPG expression, and increasing SM22α and SMA level. What's more, overexpression of circHIPK3 decreased the chondrogenic differentiation by inhibiting the protein level of SOX9, aggrecan, and collagen II. CircHIPK3 targeted miR-106a-5p and miR-106a-5p targeted MFN2. MiR-106a-5p overexpression or MFN2 depletion repressed the effect of circHIPK3 overexpression on VSMC calcification. CircHIPK3 regulated osteogenic and cartilage differentiation of VSMC via miR-106a-5p/MFN2 axis, indicating a target for treating vascular calcification.

Calcifying nanoparticles initiate the calcification process of mesenchymal stem cells in vitro through the activation of the TGF-β1/Smad signaling pathway and promote the decay of echinococcosis

The role of the calcifying nanoparticles (CNPs) in the calcification process of the outer cyst wall in hepatic cystic echinococcosis (HCE) remains unknown. CNPs were isolated from the tissues of the patients with HCE. Western blotting, alkaline phosphatase staining, and alizarin staining were performed to detect the cellular calcium ion deposition induced by the CNPs. CCK-8 and flow cytometry assays were conducted to determine the effect of CNPs on the apoptosis of mesenchymal stem cells (MSCs). Western blot experiments were performed to examine the expression levels of apoptosis-related factors and TGF-β1/Smad signaling pathway constituents. Treatment with CNPs induced the differentiation of MSCs. Calcium-related proteins, including OPN, BMP-2, and RUNX2, were upregulated after the CNP treatment. Similarly, CNP exposure increased the cellular calcium ion deposition in MSCs. In addition, the expression of Bax and Caspase-8 was elevated by the CNPs in MSCs. Treatment with CNPs promoted MSC apoptosis and inhibited the MSC growth. The TGF-β1/Smad signaling pathway was also activated after the CNP treatment. This study indicated that CNPs may play a critical role in initiating calcification of the outer cyst wall of HCE and promote the decay of echinococcosis, providing a new strategy for the treatment of hepatic echinococcosis.

Therapeutic Response of miR-145 Micelles on Patient-Derived Vascular Smooth Muscle Cells

During atherosclerosis, vascular smooth muscle cells (VSMCs) undergo a phenotypic transition from a healthy contractile state into pathological phenotypes including a proliferative and migratory, synthetic phenotype and osteochondrogenic-like phenotype that exacerbate plaques. Thus, inhibiting the transition of healthy, quiescent VSMCs to atherogenic cell types has the potential to mitigate atherosclerosis. To that end, previously, we reported that delivery of microRNA-145 (miR-145, a potent gatekeeper of the contractile VSMC phenotype) using nanoparticle micelles limited atherosclerotic plaque growth in murine models of atherosclerosis. Building on this preclinical data and toward clinical application, in this study, we tested the therapeutic viability of miR-145 micelles on patient-derived VSMCs and evaluated their effects based on disease severity. We collected vascular tissues from 11 patients with healthy, moderate, or severe stages of atherosclerosis that were discarded following vascular surgery or organ transplant, and isolated VSMCs from these tissues. We found that with increasing disease severity, patient-derived VSMCs had decreasing levels of contractile markers (miR-145, ACTA2, MYH11) and increasing levels of synthetic markers (KLF4, KLF5, and ELK1). Treatment with miR-145 micelles showed that an increase in disease severity correlated with a more robust response to therapy in VSMCs. Notably, miR-145 micelle therapy rescued contractile marker expression to baseline contractile levels in VSMCs derived from the most severely diseased tissues. As such, we demonstrate the use of miR-145 micelles across different stages of atherosclerosis disease and present further evidence of the translatability of miR-145 micelle treatment for atherosclerosis.

Exosomes in Atherosclerosis, a Double-Edged Sword: Their Role in Disease Pathogenesis and Their Potential as Novel Therapeutics

Cardiovascular disease (CAD) due to atherosclerosis is a major cause of death worldwide. The development of atherosclerosis involves intercellular communication facilitated by exosomes secreted from vascular endothelial cells (VECs), vascular smooth muscle cells (VSMCs), immune cells, and platelets. In this review, we summarize the current understanding of exosome biogenesis and uptake, and discuss atherogenic and atheroprotective functions of exosomes secreted from these cell types. In addition, we examine the potential of enhancing the therapeutic and targeting ability of exosomes exhibiting atheroprotective function by drug loading and surface modification with targeting ligands. We conclude with current challenges associated with exosome engineering for therapeutic use.

Artificial high-density lipoprotein-mimicking nanotherapeutics for the treatment of cardiovascular diseases

Despite the ability of current efficacious low-density lipoprotein-cholesterol-lowering therapies to reduce total cardiovascular disease (CVD) risks, CVD still poses major risks for morbidity and mortality to the general population. Because of the pleiotropic endothelial protective effects of high-density lipoproteins (HDL), the direct infusion of reconstituted HDL (rHDL) products, including MDCO-216, CER001, and CSL112, have been tested in clinical trials to determine whether direct infusion of rHDL can reduce coronary events in CVD patients. In addition to these rHDL products, in the past two decades, there has been an increased focused on designing artificial HDL-mimicking nanotherapeutics to produce complementary therapeutic strategies for CVD patients beyond lowering of atherogenic lipoproteins. Although recent reviews have comprehensively discussed the developments of artificial HDL-mimicking nanoparticles as therapeutics for CVD, there has been little assessment of "plain" or "drug-free" HDL-mimicking nanoparticles as therapeutics alone. In this review, we will summarize the clinical outcomes of rHDL products, examine recent advances in other types of artificial HDL-mimicking nanotherapeutics, including polymeric nanoparticles, cyclodextrins, micelles, metal nanoparticles, and so on; and potential new approaches for future CVD interventions. Moreover, success stories, lessons, and interpretations of the utility and functionality of these HDL-mimicking nanotherapeutics will be an integral part of this article. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Cardiovascular Disease.

Recent advances in nanomaterials for therapy and diagnosis for atherosclerosis

Atherosclerosis is a chronic inflammatory disease driven by lipid accumulation in arteries, leading to narrowing and thrombosis. It affects the heart, brain, and peripheral vessels and is the leading cause of mortality in the United States. Researchers have strived to design nanomaterials of various functions, ranging from non-invasive imaging contrast agents, targeted therapeutic delivery systems to multifunctional nanoagents able to target, diagnose, and treat atherosclerosis. Therefore, this review aims to summarize recent progress (2017-now) in the development of nanomaterials and their applications to improve atherosclerosis diagnosis and therapy during the preclinical and clinical stages of the disease.

Oral delivery of metformin by chitosan nanoparticles for polycystic kidney disease

Nanoparticle drug delivery has many advantages over small molecule therapeutics, including reducing off-target side effects and increasing drug potency. However, many nanoparticles are administered parenterally, which is challenging for chronic diseases such as polycystic kidney disease (PKD), the most common hereditary disease worldwide in which patients need continuous treatment over decades. To address this clinical need, we present the development of nanoparticles synthesized from chitosan, a widely available polymer chosen for its ability to improve oral bioavailability. Specifically, we optimized the synthesis parameters of chitosan nanoparticles and demonstrate mucoadhesion and permeation across an intestinal barrier model in vitro. Furthermore, when administered orally to mice, ex vivo imaging of rhodamine-loaded chitosan nanoparticles showed significantly higher accumulation in the intestines compared to the free model drug, as well as 1.3 times higher serum area under the curve (AUC), demonstrating controlled release and improved serum delivery over 24 h. To test its utility for chronic diseases such as PKD, we loaded the candidate PKD drug, metformin, into chitosan nanoparticles, and upon oral administration to a PKD murine model (Pkd1fl/fl;Pax8-rtTA;Tet-O cre), a lower cyst burden was observed compared to free metformin, and was well tolerated upon repeated dosages. Blood urea nitrogen (BUN) and creatinine levels were similar to untreated mice, demonstrating kidney and biocompatibility health. Our study builds upon previous chitosan-based drug delivery approaches, and demonstrates a novel, oral nanoformulation for PKD.

CCR2-targeted micelles for anti-cancer peptide delivery and immune stimulation

Signaling between the CC chemokine receptor 2 (CCR2) with its ligand, monocyte chemoattractant protein-1 (MCP-1) promotes cancer progression by directly stimulating tumor cell proliferation and downregulating the expression of apoptotic proteins. Additionally, the MCP-1/CCR2 signaling axis drives the migration of circulating monocytes into the tumor microenvironment, where they mature into tumor-associated macrophages (TAMs) that promote disease progression through induction of angiogenesis, tissue remodeling, and suppression of the cytotoxic T lymphocyte (CTL) response. In order to simultaneously disrupt MCP-1/CCR2 signaling and target CCR2-expressing cancer cells for drug delivery, KLAK-MCP-1 micelles consisting of a CCR2-targeting peptide sequence (MCP-1 peptide) and the apoptotic KLAKLAK peptide were synthesized. In vitro, KLAK-MCP-1 micelles were observed to bind and induce cytotoxicity to cancer cells through interaction with CCR2. In vivo, KLAK-MCP-1 micelles inhibited tumor growth (34 ± 11%) in a subcutaneous B16F10 murine melanoma model despite minimal tumor accumulation upon intravenous injection. Tumors treated with KLAK-MCP1 demonstrated reduced intratumor CCR2 expression and altered infiltration of TAMs and CTLs as evidenced by immunohistochemical and flow cytometric analysis. These studies highlight the potential application of CCR2-targeted nanotherapeutic micelles in cancer treatment.

Transdermal Delivery of Kidney-Targeting Nanoparticles Using Dissolvable Microneedles

INTRODUCTION

Chronic kidney disease (CKD) affects approximately 13% of the world's population and will lead to dialysis or kidney transplantation. Unfortunately, clinically available drugs for CKD show limited efficacy and toxic extrarenal side effects. Hence, there is a need to develop targeted delivery systems with enhanced kidney specificity that can also be combined with a patient-compliant administration route for such patients that need extended treatment. Towards this goal, kidney-targeted nanoparticles administered through transdermal microneedles (KNP/MN) is explored in this study.

METHODS

A KNP/MN patch was developed by incorporating folate-conjugated micelle nanoparticles into polyvinyl alcohol MN patches. Rhodamine B (RhB) was encapsulated into KNP as a model drug and evaluated for biocompatibility and binding with human renal epithelial cells. For MN, skin penetration efficiency was assessed using a Parafilm model, and penetration was imaged via scanning electron microscopy. In vivo, KNP/MN patches were applied on the backs of C57BL/6 wild type mice and biodistribution, organ morphology, and kidney function assessed.

RESULTS

KNP showed high biocompatibility and folate-dependent binding in vitro, validating KNP's targeting to folate receptors in vitro. Upon transdermal administration in vivo, KNP/MN patches dissolved within 30 min. At varying time points up to 48 h post-KNP/MN administration, higher accumulation of KNP was found in kidneys compared with MN that consisted of the non-targeting, control-NP. Histological evaluation demonstrated no signs of tissue damage, and kidney function markers, serum blood urea nitrogen and urine creatinine, were found to be within normal ranges, indicating preservation of kidney health.

CONCLUSIONS

Our studies show potential of KNP/MN patches as a non-invasive, self-administrable platform to direct therapies to the kidneys.

The effect of size, charge, and peptide ligand length on kidney targeting by small, organic nanoparticles

Chronic kidney disease (CKD) affects 15% of the US adult population. However, most clinically available drugs for CKD show low bioavailability to the kidneys and non-specific uptake by other organs which results in adverse side effects. Hence, a targeted, drug delivery strategy to enhance kidney drug delivery is highly desired. Recently, our group developed small, organic nanoparticles called peptide amphiphile micelles (PAM) functionalized with the zwitterionic peptide ligand, (KKEEE)3K, that passage through the glomerular filtration barrier for kidney accumulation. Despite high bioavailability to the kidneys, these micelles also accumulated in the liver to a similar extent. To further optimize the physicochemical properties and develop design rules for kidney-targeting micelles, we synthesized a library of PAMs of varying size, charge, and peptide repeats. Specifically, variations of the original (KKEEE)3K peptide including (KKEEE)2K, (KKEEE)K, (EEKKK)3E, (EEKKK)2E, (EEKKK)E, KKKKK, and EEEEE were functionalized onto nanoparticles, and peptide surface density and PEG linker molecular weight were altered. After characterization with transmission electron microscopy (TEM) and dynamic light scattering (DLS), nanoparticles were intravenously administered into wildtype mice, and biodistribution was assessed through ex vivo imaging. All micelles localized to the kidneys, but nanoparticles that are positively-charged, close to the renal filtration size cut-off, and consisted of additional zwitterionic peptide sequences generally showed higher renal accumulation. Upon immunohistochemistry, micelles were confirmed to bind to the multiligand receptor, megalin, and histological analyses showed no tissue damage. Our study provides insight into the design of micelle carriers for kidney targeting and their potential for future therapeutic application.

Targeting and therapeutic peptide-based strategies for polycystic kidney disease

Polycystic kidney disease (PKD) is characterized by progressive cyst growth and is a leading cause of renal failure worldwide. Currently, there are limited therapeutic options available to PKD patients, and only one drug, tolvaptan, has been FDA-approved to slow cyst progression. Similar to other small molecule drugs, however, tolvaptan is costly, only moderately effective, and causes adverse events leading to high patient dropout rates. Peptides may mitigate many drawbacks of small molecule drugs, as they can be highly tissue-specific, biocompatible, and economically scaled-up. Peptides can function as targeting ligands that direct therapies to diseased renal tissue, or be potent as therapeutic agents themselves. This review discusses various aberrant signaling pathways in PKD and renal receptors that can be potential targets of peptide-mediated strategies. Additionally, peptides utilized in other kidney applications, but may prove useful in the context of PKD, are highlighted. Insights into novel peptide-based solutions that have potential to improve clinical management of PKD are provided.

Collagenase-Cleavable Peptide Amphiphile Micelles as a Novel Theranostic Strategy in Atherosclerosis

Atherosclerosis is an inflammatory disease characterized by plaques that can cause sudden myocardial infarction upon rupture. Such rupture-prone plaques have thin fibrous caps due to collagenase degradation, and a noninvasive diagnostic tool and targeted therapy that can identify and treat vulnerable plaques and may inhibit the onset of acute cardiac events. Toward this goal, monocyte-binding, collagenase-inhibiting, and gadolinium-modified peptide amphiphile micelles (MCG PAMs) are developed. Monocyte chemoattractant protein-1 (MCP-1) binds to C-C chemokine receptor-2 expressed on pathological cell types present within plaques. Through the peptide binding motif of MCP-1, MCG PAMs bind to monocytes and vascular smooth muscle cells in vitro. Moreover, using magnetic resonance imaging, MCG PAMs show enhanced targeting and successful detection of plaques in diseased mice in vivo and act as contrast agents for molecular imaging. Through the collagenase-cleaving peptide sequence of collagen [VPMS-MRGG], MCG PAMs can compete for collagenases that degrade the fibrous cap of plaques, providing therapy. MCG PAM-treated mice show increased fibrous cap thickness by 61% and 113% histologically compared to nontargeting micelle- or PBS-treated mice (p = 0.0075 and 0.001, respectively). Overall, this novel multimodal nanoparticle offers new theranostic opportunities for noninvasive diagnosis and treatment of atherosclerotic plaques.