Gold nanoparticles that target degraded elastin improve imaging and rupture prediction in an AngII mediated mouse model of abdominal aortic aneurysm

In-silico study of drug delivery to atherosclerosis in the human carotid artery using metal-organic frameworks based on adhesion of nanocarriers

This study investigates nanocarriers (NCs) for drug delivery targeting carotid artery atherosclerosis. This targeted drug delivery mechanism is based on ligand-receptor bindings facilitated by coating NCs with P-selectin aptamers, which exhibit high affinities for P-selectin plaque receptors. Recognizing the significant advantages of metal-organic frameworks (MOFs), such as their high drug-loading percentages, we chose them as nanocarriers for this research. Our evaluation considers critical factors: NC surface density (the number of attached nanocarriers per unit of plaque area), toxicity (percentage of NCs missing the target), and efficient drug transfer to plaque tissue. Employing molecular dynamics (MD) for drug loading calculations via van der Waals interactions and computational fluid dynamics (CFD) for toxicity, surface density, and drug transfer assessments, we achieve a comprehensive analysis. A cardiac cycle-based metric guides optimal MOF release conditions, establishing an ideal dosage of 600 NCs per cycle. MOF-801 exhibits outstanding drug delivery performance, particularly in plaque targeting. While a magnetic field enhances NC adhesion, its impact on drug transfer is limited, emphasizing the need for further optimization in magnetic targeting for NC-based therapies. This study provides crucial insights into NC drug delivery performance in carotid artery atherosclerosis, advancing the field of targeted drug delivery for atherosclerosis treatment.

Improved Reversion of Calcifications in Porcine Aortic Heart Valves Using Elastin-Targeted Nanoparticles

Calcified aortic valve disease in its final stage leads to aortic valve stenosis, limiting cardiac function. To date, surgical intervention is the only option for treating calcific aortic valve stenosis. This study combined controlled drug delivery by nanoparticles (NPs) and active targeting by antibody conjugation. The chelating agent diethylenetriaminepentaacetic acid (DTPA) was covalently bound to human serum albumin (HSA)-based NP, and the NP surface was modified using conjugating antibodies (anti-elastin or isotype IgG control). Calcification was induced ex vivo in porcine aortic valves by preincubation in an osteogenic medium containing 2.5 mM sodium phosphate for five days. Valve calcifications mainly consisted of basic calcium phosphate crystals. Calcifications were effectively resolved by adding 1-5 mg DTPA/mL medium. Incubation with pure DTPA, however, was associated with a loss of cellular viability. Reversal of calcifications was also achieved with DTPA-coupled anti-elastin-targeted NPs containing 1 mg DTPA equivalent. The addition of these NPs to the conditioned media resulted in significant regression of the valve calcifications compared to that in the IgG-NP control without affecting cellular viability. These results represent a step further toward the development of targeted nanoparticular formulations to dissolve aortic valve calcifications.

Human Health Risk Assessments and Characterization of Nanomaterials: Are We Ready for the Next (Active) Generations?

Driven by the concept of the 'four generations of nanomaterials', the current state of the knowledge on risk assessment of future generation is explored for active nanomaterials. Through case studies, we identify challenges and evaluate the preparedness of characterization methods, available risk assessment modeling tools, and analytical instrumentation for such future generation active nanomaterials with dynamic hybrid structures of biotic-abiotic and organic-inorganic combinations. Currently available risk assessment tools and analytical instrumentation were found to be lacking the risk preparedness and characterization readiness for active nanomaterials, respectively. Potential future developments in risk assessment modeling tools and analytical techniques can be based upon this work which shall ensure long-term safety of the next generation of nanomaterials.

Nanoparticle-Assisted Diagnosis and Treatment for Abdominal Aortic Aneurysm

An abdominal aortic aneurysm (AAA) is a localized dilatation of the aorta related to the regional weakening of the wall structure, resulting in substantial morbidity and mortality with the aortic ruptures as complications. Ruptured AAA is a dramatic catastrophe, and aortic emergencies constitute one of the leading causes of acute death in older adults. AAA management has been centered on surgical repair of larger aneurysms to mitigate the risks of rupture, and curative early diagnosis and effective pharmacological treatments for this condition are still lacking. Nanoscience provided a possibility of more targeted imaging and drug delivery system. Multifunctional nanoparticles (NPs) may be modified with ligands or biomembranes to target agents' delivery to the lesion site, thus reducing systemic toxicity. Furthermore, NPs can improve drug solubility, circulation time, bioavailability, and efficacy after systemic administration. The varied judiciously engineered nano-biomaterials can exist stably in the blood vessels for a long time without being taken up by cells. Here, in this review, we focused on the NP application in the imaging and treatment of AAA. We hope to make an overview of NP-assisted diagnoses and therapy in AAA and discussed the potential of NP-assisted treatment.

MicroRNA-199a-5p aggravates angiotensin II-induced vascular smooth muscle cell senescence by targeting Sirtuin-1 in abdominal aortic aneurysm

Vascular smooth muscle cells (VSMCs) senescence contributes to abdominal aortic aneurysm (AAA) formation although the underlying mechanisms remain unclear. This study aimed to investigate the role of miR-199a-5p in regulating VSMC senescence in AAA. VSMC senescence was determined by a senescence-associated β-galactosidase (SA-β-gal) assay. RT-PCR and Western blotting were performed to measure miRNA and protein level, respectively. The generation of reactive oxygen species (ROS) was evaluated by H2DCFDA staining. Dual-luciferase reporter assay was used to validate the target gene of miR-199a-5p. VSMCs exhibited increased senescence in AAA tissue relative to healthy aortic tissue from control donors. Compared with VSMCs isolated from control donors (control-VSMCs), those derived from patients with AAA (AAA-VSMCs) exhibited increased cellular senescence and ROS production. Angiotensin II (Ang II) induced VSMC senescence by promoting ROS generation. The level of miR-199a-5p expression was upregulated in the plasma from AAA patients and Ang II-treated VSMCs. Mechanistically, Ang II treatment significantly elevated miR-199a-5p level, thereby stimulating ROS generation by repressing Sirt1 and consequent VSMC senescence. Nevertheless, Ang II-induced VSMC senescence was partially attenuated by a miR-199a-5p inhibitor or Sirt1 activator. Our study revealed that miR-199a-5p aggravates Ang II-induced VSMC senescence by targeting Sirt1 and that miR-199a-5p is a potential therapeutic target for AAA.

Early Detection of Aortic Degeneration in a Mouse Model of Sporadic Aortic Aneurysm and Dissection Using Nanoparticle Contrast-Enhanced Computed Tomography

[Figure: see text].

Nanomaterials as Novel Cardiovascular Theranostics

Cardiovascular diseases (CVDs) are a group of conditions associated with heart and blood vessels and are considered the leading cause of death globally. Coronary heart disease, atherosclerosis, myocardial infarction represents the CVDs. Since CVDs are associated with a series of pathophysiological conditions with an alarming mortality and morbidity rate, early diagnosis and appropriate therapeutic approaches are critical for saving patients’ lives. Conventionally, diagnostic tools are employed to detect disease conditions, whereas therapeutic drug candidates are administered to mitigate diseases. However, the advent of nanotechnological platforms has revolutionized the current understanding of pathophysiology and therapeutic measures. The concept of combinatorial therapy using both diagnosis and therapeutics through a single platform is known as theranostics. Nano-based theranostics are widely used in cancer detection and treatment, as evident from pre-clinical and clinical studies. Nanotheranostics have gained considerable attention for the efficient management of CVDs. The differential physicochemical properties of engineered nanoparticles have been exploited for early diagnosis and therapy of atherosclerosis, myocardial infarction and aneurysms. Herein, we provided the information on the evolution of nano-based theranostics to detect and treat CVDs such as atherosclerosis, myocardial infarction, and angiogenesis. The review also aims to provide novel avenues on how nanotherapeutics’ trending concept could transform our conventional diagnostic and therapeutic tools in the near future.

Animal Model Dependent Response to Pentagalloyl Glucose in Murine Abdominal Aortic Injury

Abdominal aortic aneurysms (AAAs) are a local dilation of the aorta and are associated with significant mortality due to rupture and treatment complications. There is a need for less invasive treatments to prevent aneurysm growth and rupture. In this study, we used two experimental murine models to evaluate the potential of pentagalloyl glucose (PGG), which is a polyphenolic tannin that binds to and crosslinks elastin and collagen, to preserve aortic compliance. Animals underwent surgical aortic injury and received 0.3% PGG or saline treatment on the adventitial surface of the infrarenal aorta. Seventeen mice underwent topical elastase injury, and 14 mice underwent topical calcium chloride injury. We collected high-frequency ultrasound images before surgery and at 3-4 timepoints after. There was no difference in the in vivo effective maximum diameter due to PGG treatment for either model. However, the CaCl2 model had significantly higher Green-Lagrange circumferential cyclic strain in PGG-treated animals (p < 0.05). While ex vivo pressure-inflation testing showed no difference between groups in either model, histology revealed reduced calcium deposits in the PGG treatment group with the CaCl2 model. These findings highlight the continued need for improved understanding of PGG's effects on the extracellular matrix and suggest that PGG may reduce arterial calcium accumulation.

The Association Between Curvature and Rupture in a Murine Model of Abdominal Aortic Aneurysm and Dissection

BACKGROUND

Mouse models of abdominal aortic aneurysm (AAA) and dissection have proven to be invaluable in the advancement of diagnostics and therapeutics by providing a platform to decipher response variables that are elusive in human populations. One such model involves systemic Angiotensin II (Ang-II) infusion into low density-lipoprotein receptor-deficient (LDLr-/-) mice leading to intramural thrombus formation, inflammation, matrix degradation, dilation, and dissection. Despite its effectiveness, considerable experimental variability has been observed in AAAs taken from our Ang-II infused LDLr-/- mice (n=12) with obvious dissection occurring in 3 samples, outer bulge radii ranging from 0.73 to 2.12 mm, burst pressures ranging from 155 to 540 mmHg, and rupture location occurring 0.05 to 2.53 mm from the peak bulge location.

OBJECTIVE

We hypothesized that surface curvature, a fundamental measure of shape, could serve as a useful predictor of AAA failure at supra-physiological inflation pressures.

METHODS

To test this hypothesis, we fit well-known biquadratic surface patches to 360° micro-mechanical test data and used Spearman's rank correlation (rho) to identify relationships between failure metrics and curvature indices.

RESULTS

We found the strongest associations between burst pressure and the maximum value of the first principal curvature (rho=-0.591, p-val=0.061), the maximum value of Mean curvature (rho=-0.545, p-val=0.087), and local values of Mean curvature at the burst location (rho=-0.864, p-val=0.001) with only the latter significant after Bonferroni correction. Additionally, the surface profile at failure was predominantly convex and hyperbolic (saddle-shaped) as indicated by a negative sign in the Gaussian curvature. Findings reiterate the importance of shape in experimental models of AAA.

Nano-Biomaterials for the Delivery of Therapeutic and Monitoring Cues for Aortic Diseases

The aorta is the largest artery in the body, so any diseases or conditions which could cause damage to the aorta would put patients at considerable and life-threatening risk. In the management of aortic diseases, the major treatments include drug therapy, endovascular treatment, and surgical treatment, which are of great danger or with a poor prognosis. The delivery of nano-biomaterials provides a potential development trend and an emerging field where we could monitor patients’ conditions and responses to the nanotherapeutics. One of the putative applications of nanotechnology is ultrasensitive monitoring of cardiovascular markers by detecting and identifying aneurysms. Moreover, the use of nanosystems for targeted drug delivery can minimize the systemic side effects and enhance drug positioning and efficacy compared to conventional drug therapies. This review shows some examples of utilizing nano-biomaterials in in vitro organ and cell culture experiments and explains some developing technologies in delivering and monitoring regenerative therapeutics.

Recent progress on nanoparticles for targeted aneurysm treatment and imaging

An abdominal aortic aneurysm (AAA) is a localized dilatation of the aorta that plagues millions. Its rupture incurs high mortality rates (~80-90%), pressing an urgent need for therapeutic methods to prevent this deadly outcome. Judiciously designed nanoparticles (NPs) have displayed a unique potential to fulfill this need. Aneurysms feature excessive inflammation and extracellular matrix (ECM) degradation. As such, typically inflammatory cells and exposed ECM proteins have been targeted with NPs for therapeutic, diagnostic, or theranostic purposes in experimental models. NPs have been used not only for encapsulation and delivery of drugs and biomolecules in preclinical tests, but also for enhanced imaging to monitor aneurysm progression in patients. Moreover, they can be readily modified with various molecules to improve lesion targeting, detectability, biocompatibility, and circulation time. This review updates on the progress, limitations, and prospects of NP applications in the context of AAA.

Null strain analysis of submerged aneurysm analogues using a novel 3D stereomicroscopy device

To measure the inhomogeneous 3D-strain fields present during inflation-extension testing of physiologically submerged micro-aneurysms, a Stereo Digital Image Correlation (StereoDIC) microscopy system is developed that revolves 15° stereo-angle cameras around a centrally-mounted target. Calibration is performed using submerged dot patterns and system accuracy verified using strain and deformation analyses for rigid body motions of speckle-patterned, micro-aneurysmal surrogates. In terms of the Green-Lagrange strain tensor and the 3D displacement fields, the results are stable even after 120 minutes, with maxima in both strain bias and strain standard deviation less than 2E-03 for all components, and micron-level displacement standard deviation.

Nano-Medicine for Thrombosis: A Precise Diagnosis and Treatment Strategy

Thrombosis is a global health issue and one of the leading factors of death. However, its diagnosis has been limited to the late stages, and its therapeutic window is too narrow to provide reasonable and effective treatment. In addition, clinical thrombolytics suffer from a short half-life, allergic reactions, inactivation, and unwanted tissue hemorrhage. Nano-medicines have gained extensive attention in diagnosis, drug delivery, and photo/sound/magnetic-theranostics due to their convertible properties. Furthermore, diagnosis and treatment of thrombosis using nano-medicines have also been widely studied. This review summarizes the recent advances in this area, which revealed six types of nanoparticle approaches: (1) in vitro diagnostic kits using "synthetic biomarkers"; (2) in vivo imaging using nano-contrast agents; (3) targeted drug delivery systems using artificial nanoparticles; (4) microenvironment responsive drug delivery systems; (5) drug delivery systems using biological nanostructures; and (6) treatments with external irradiation. The investigations of nano-medicines are believed to be of great significance, and some of the advanced drug delivery systems show potential applications in clinical theranotics.

Targeted Gold Nanoparticles as an Indicator of Mechanical Damage in an Elastase Model of Aortic Aneurysm

Elastin is a key structural protein and its pathological degradation deterministic in aortic aneurysm (AA) outcomes. Unfortunately, using current diagnostic and clinical surveillance techniques the integrity of the elastic fiber network can only be assessed invasively. To address this, we employed fragmented elastin-targeting gold nanoparticles (EL-AuNPs) as a diagnostic tool for the evaluation of unruptured AAs. Electron dense EL-AuNPs were visualized within AAs using micro-computed tomography (micro-CT) and the corresponding Gold-to-Tissue volume ratios quantified. The Gold-to-Tissue volume ratios correlated strongly with the concentration (0, 0.5, or 10 U/mL) of infused porcine pancreatic elastase and therefore the degree of elastin damage. Hyperspectral mapping confirmed the spatial targeting of the EL-AuNPs to the sites of damaged elastin. Nonparametric Spearman's rank correlation indicated that the micro-CT-based Gold-to-Tissue volume ratios had a strong correlation with loaded (ρ = 0.867, p-val = 0.015) and unloaded (ρ = 0.830, p-val = 0.005) vessel diameter, percent dilation (ρ = 0.976, p-val = 0.015), circumferential stress (ρ = 0.673, p-val = 0.007), loaded (ρ = - 0.673, p-val = 0.017) and unloaded (ρ = - 0.697, p-val = 0.031) wall thicknesses, circumferential stretch (ρ = - 0.7234, p-val = 0.018), and lumen area compliance (ρ = - 0.831, p-val = 0.003). Likewise, in terms of axial force and axial stress vs. stretch, the post-elastase vessels were stiffer. Collectively, these findings suggest that, when combined with CT imaging, EL-AuNPs can be used as a powerful tool in the non-destructive estimation of mechanical and geometric features of AAs.

Nanoparticle-based targeted delivery of pentagalloyl glucose reverses elastase-induced abdominal aortic aneurysm and restores aorta to the healthy state in mice

AIM

Abdominal aortic aneurysms (AAA) is a life-threatening weakening and expansion of the abdominal aorta due to inflammatory cell infiltration and gradual degeneration of extracellular matrix (ECM). There are no pharmacological therapies to treat AAA. We tested the hypothesis that nanoparticle (NP) therapy that targets degraded elastin and delivers anti-inflammatory, anti-oxidative, and ECM stabilizing agent, pentagalloyl glucose (PGG) will reverse advance stage aneurysm in an elastase-induced mouse model of AAA.

METHOD AND RESULTS

Porcine pancreatic elastase (PPE) was applied periadventitially to the infrarenal aorta in mice and AAA was allowed to develop for 14 days. Nanoparticles loaded with PGG (EL-PGG-NPs) were then delivered via IV route at 14-day and 21-day (10 mg/kg of body weight). A control group of mice received no therapy. The targeting of NPs to the AAA site was confirmed with fluorescent dye marked NPs and gold NPs. Animals were sacrificed at 28-d. We found that targeted PGG therapy reversed the AAA by decreasing matrix metalloproteinases MMP-9 and MMP-2, and the infiltration of macrophages in the medial layer. The increase in diameter of the aorta was reversed to healthy controls. Moreover, PGG treatment restored degraded elastic lamina and increased the circumferential strain of aneurysmal aorta to the healthy levels.

CONCLUSION

Our results support that site-specific delivery of PGG with targeted nanoparticles can be used to treat already developed AAA. Such therapy can reverse inflammatory markers and restore arterial homeostasis.