Cells and iron oxide nanoparticles on the move: magnetic resonance imaging of monocyte homing and myocardial inflammation in patients with ST-elevation myocardial infarction

Metal-based nanoparticles: Promising tools for the management of cardiovascular diseases

Cardiovascular disease (CVD) is the leading cause of death worldwide. A search for more effective treatments of CVD is increasingly needed. Major advances in nanotechnology opened new avenues in CVD therapeutics. Owing to their special properties, iron oxide, gold and silver nanoparticles (NPs) could exert various effects in the management and treatment of CVD. The role of iron oxide NPs in the detection and identification of atherosclerotic plaques is receiving increased attention. Moreover, these NPs enhance targeted stem cell delivery, thereby potentiating the regenerative capacity at the injured sites. In addition to their antioxidative and antihypertrophic capacities, gold NPs have also been shown to be useful in the identification of plaques and recognition of inflammatory markers. Contrary to first reports suggestive of their cardio-vasculoprotective role, silver NPs now appear to exert negative effects on the cardiovascular system. Indeed, these NPs appear to negatively modulate inflammation and cholesterol uptake, both of which exacerbate atherosclerosis. Moreover, silver NPs may precipitate bradycardia, conduction block and sudden cardiac death. In this review, we dissect the cellular responses and toxicity profiles of these NPs from various perspectives including cellular and molecular ones.

Association of eosinophil-to-monocyte ratio with 1-month and long-term all-cause mortality in patients with ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention

Background

To determine the relationship between eosinophil-to-monocyte ratio (EMR) on admission and one-month and long-term all-cause mortality in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (P-PCI).

Methods

A total of 426 consecutive STEMI patients treated with P-PCI were enrolled and categorized in terms of tertiles of EMR on admission between September 2015 and October 2017. Final follow-up for long-term outcomes was January 2017.

Results

As EMR decreased, all-cause mortality at 1 month (mean, 29.5±3.5 days) and at mean 14.1±7.8 months follow-up increased (P=0.012, P=0.003, respectively). Kaplan-Meier survival curve analysis showed EMR was associated with 1-month and long-term all-cause mortality (P=0.048, P=0.015, respectively). In multivariate Cox proportional hazards analysis, EMR was independently associated with one-month and long-term mortality (hazard ratio =0.097; 95% CI, 0.010-0.899; P=0.04; hazard ration =0.176; 95% CI, 0.045-0.694; P=0.013). The area under the curve of EMR for the prediction of 1-month and long-term total mortality in receiver operating characteristic analysis was 0.789 (95% CI, 0.658-0.921; P=0.003) and 0.752 (95% CI, 0.619-0.884; P=0.001), respectively.

Conclusions

EMR on admission was independently correlated with 1-month and long-term all-cause mortality in STEMI patients undergoing P-PCI, suggesting EMR as a potential simple, useful, and inexpensive index for risk stratification of STEMI patients.

Low-dose combined exposure of nanoparticles and heavy metal compared with PM2.5 in human myocardial AC16 cells

The co-exposure toxicity mechanism of ultrafine particles and pollutants on human cardiovascular system are still unclear. In this study, the combined effects of silica nanoparticles (SiNPs) and/or carbon black nanoparticles (CBNPs) with Pb(AC)₂ compared with particulate matter (PM)_2.5 were investigated in human myocardial cells (AC16). Our study detected three different combinations of SiNPs and Pb(AC)₂, CBNPs and Pb(AC)₂, and SiNPs and CBNPs compared with PM_2.5 at low-dose exposure. Using PM_2.5 as positive control, our results suggested that the combination of SiNPs and Pb(AC)₂/CBNPs could increase the production of reactive oxygen species (ROS), lactate dehydrogenase leakage (LDH), and malondialdehyde (MDA) and decrease the activities of superoxide dismutase (SOD) and glutathione (GSH); induce inflammation by the upregulation of protein CRP and TNF-α, and apoptosis by the upregulation of protein caspase-3, caspase-9, and Bax while the downregulation of protein Bcl-2; and trigger G2/M phase arrest by the upregulation of protein Chk2 and downregulation of protein Cdc2 and cyclin B1. In addition, the combination of CBNPs and Pb(AC)₂ induced a significant increase in MDA and reduced the activities of ROS, LDH, SOD, and GSH, with G1/S phase arrest via upregulation of Chk1 and downregulation of CDK6 and cyclin D1. Our data suggested that the additive interaction and synergistic interaction are the major interaction in co-exposure system, and PM_2.5 could trigger more severe oxidative stress, G2/M arrest, and apoptosis than either co-exposure or single exposure.

Dual-targeting Theranostic System with Mimicking Apoptosis to Promote Myocardial Infarction Repair via Modulation of Macrophages

Currently unsatisfactory treatment of myocardial infarction (MI) is due to the unbridled inflammation and the delayed diagnosis at the early stage. To address these problems, firstly, phosphatidylserine (PS) was used to modulate the phenotypes of macrophages (MΦ) and resolve the early inflammation via binding to PS receptors (PSR) on macrophage surface. Secondly, highly-sensitive magnetic iron oxide nanocubes (MIONs) were adopted to realize the early visualization via magnetic resonance imaging (MRI). However, the major drawback for MIONs as contrast agents was their hydrophobic properties and insufficient delivery. Hence, zwitterionic biodegradable copolymer poly(lactide)-polycarboxybetaine (PLA-PCB, PP), companied with PS, was used to provide a good colloidal stability and long blood circulation for the nanocubes. Given the above, a theranostic nanosystem (PP/PS@MIONs) was constructed for early treatment of MI. With external magnetic field-induced targeting and PS targeting, the nanosystem enhanced the accumulation in infarcted area, and accelerated the resolution of early inflammatory responses. Moreover, the nanocubes in system were promoted to escape from endosomes/lysosomes via protonation of PCB, which contributes to accurate MRI. This nanosystem showed good inflammation-resolving effects and imaging ability in MI model rats. Therefore, this theranostic nanosystem can realize accurate visualization and significantly improve the treatment efficacy of MI at early stage.

In focus: Fe3O4 nanoparticles and human mesenteric artery interaction in vitro

Aim: The growing implementation of iron oxide nanoparticles in medicine requires a thorough investigation of their physiological influence. Therefore, effects of Fe3O4 nanoparticles on isometric contractions of healthy human mesenteric artery in vitro were investigated. Materials & methods: The effect of increasing concentrations (0.023, 0.069, 0.23, 0.69 and 2.31 μg/μl) of Fe3O4 nanoparticles (50–100 nm) on the contractility of mesenteric artery ring preparations was studied using wire myography technique. Results & conclusion: A lack of effects of Fe3O4 nanoparticles (50–100 nm) on isometric contractions of human mesenteric artery segments both in conditions of basal tension and precontraction was found. The observed unresponsiveness of human mesenteric arteries in vitro to Fe3O4 nanoparticles could be attributed to their safe mode of use in biomedicine.

Imaging systemic inflammatory networks in ischemic heart disease

While acute myocardial infarction mortality declines, patients continue to face reinfarction and/or heart failure. The immune system, which intimately interacts with healthy and diseased tissues through resident and recruited leukocytes, is a central interface for a global host response to ischemia. Pathways that enhance the systemic leukocyte supply may be potential therapeutic targets. Pre-clinically, imaging helps to identify immunity's decision nodes, which may serve as such targets. In translating the rapidly-expanding pre-clinical data on immune activity, the difficulty of obtaining multiple clinical tissue samples from involved organs is an obstacle that whole-body imaging can help overcome. In patients, molecular and cellular imaging can be integrated with blood-based diagnostics to assess the translatability of discoveries, including the activation of hematopoietic tissues after myocardial infarction, and serve as an endpoint in clinical trials. In this review, we discuss these concepts while focusing on imaging immune activity in organs involved in ischemic heart disease.

Nanoparticles for imaging: top or flop?

Nanoparticles are frequently suggested as diagnostic agents. However, except for iron oxide nanoparticles, diagnostic nanoparticles have been barely incorporated into clinical use so far. This is predominantly due to difficulties in achieving acceptable pharmacokinetic properties and reproducible particle uniformity as well as to concerns about toxicity, biodegradation, and elimination. Reasonable indications for the clinical utilization of nanoparticles should consider their biologic behavior. For example, many nanoparticles are taken up by macrophages and accumulate in macrophage-rich tissues. Thus, they can be used to provide contrast in liver, spleen, lymph nodes, and inflammatory lesions (eg, atherosclerotic plaques). Furthermore, cells can be efficiently labeled with nanoparticles, enabling the localization of implanted (stem) cells and tissue-engineered grafts as well as in vivo migration studies of cells. The potential of using nanoparticles for molecular imaging is compromised because their pharmacokinetic properties are difficult to control. Ideal targets for nanoparticles are localized on the endothelial luminal surface, whereas targeted nanoparticle delivery to extravascular structures is often limited and difficult to separate from an underlying enhanced permeability and retention (EPR) effect. The majority of clinically used nanoparticle-based drug delivery systems are based on the EPR effect, and, for their more personalized use, imaging markers can be incorporated to monitor biodistribution, target site accumulation, drug release, and treatment efficacy. In conclusion, although nanoparticles are not always the right choice for molecular imaging (because smaller or larger molecules might provide more specific information), there are other diagnostic and theranostic applications for which nanoparticles hold substantial clinical potential.

Implications of protein corona on physico-chemical and biological properties of magnetic nanoparticles

Interaction of serum proteins and nanoparticles leads to a nanoparticle-protein complex formation that defines the rational strategy for a clinically relevant formulation for drug delivery, hyperthermia, and magnetic resonance imaging (MRI) applications in cancer nanomedicine. Given this perspective, we have examined the pattern of human serum protein corona formation with our recently engineered magnetic nanoparticles (MNPs). The alteration in particle size, zeta potential, hemotoxicity, cellular uptake/cancer cells targeting potential, and MRI properties of the MNPs after formation of human serum (HS) protein corona were studied. Our results indicated no significant change in particle size of our MNPs upon incubation with 0.5-50 wt/v% human serum, while zeta potential of MNPs turned negative due to human serum adsorption. When incubated with an increased serum and particle concentration, apolipoprotein E was adsorbed on the surface of MNPs apart from serum albumin and transferrin. However, there was no significant primary or secondary structural alterations observed in serum proteins through Fourier transform infrared spectroscopy, X-ray diffraction, and circular dichroism. Hemolysis assay suggests almost no hemolysis at the tested concentrations (up to 1 mg/mL) for MNPs compared to the sodium dodecyl sulfate (positive control). Additionally, improved internalization and uptake of MNPs by C4-2B and Panc-1 cancer cells were observed upon incubation with human serum (HS). After serum protein adsorption to the surface of MNPs, the close vicinity within T1 (∼1.33-1.73 s) and T2 (∼12.35-13.43 ms) relaxation times suggest our MNPs retained inherent MRI potential even after biomolecular protein adsorption. All these superior clinical parameters potentially enable clinical translation and use of this formulation for next generation nanomedicine for drug delivery, cancer-targeting, imaging and theranostic applications.

Cancer immunotherapy: nanodelivery approaches for immune cell targeting and tracking

Cancer is one of the most common diseases afflicting people globally. New therapeutic approaches are needed due to the complexity of cancer as a disease. Many current treatments are very toxic and have modest efficacy at best. Increased understanding of tumor biology and immunology has allowed the development of specific immunotherapies with minimal toxicity. It is important to highlight the performance of monoclonal antibodies, immune adjuvants, vaccines and cell-based treatments. Although these approaches have shown varying degrees of clinical efficacy, they illustrate the potential to develop new strategies. Targeted immunotherapy is being explored to overcome the heterogeneity of malignant cells and the immune suppression induced by both the tumor and its microenvironment. Nanodelivery strategies seek to minimize systemic exposure to target therapy to malignant tissue and cells. Intracellular penetration has been examined through the use of functionalized particulates. These nano-particulate associated medicines are being developed for use in imaging, diagnostics and cancer targeting. Although nano-particulates are inherently complex medicines, the ability to confer, at least in principle, different types of functionality allows for the plausible consideration these nanodelivery strategies can be exploited for use as combination medicines. The development of targeted nanodelivery systems in which therapeutic and imaging agents are merged into a single platform is an attractive strategy. Currently, several nanoplatform-based formulations, such as polymeric nanoparticles, micelles, liposomes and dendrimers are in preclinical and clinical stages of development. Herein, nanodelivery strategies presently investigated for cancer immunotherapy, cancer targeting mechanisms and nanocarrier functionalization methods will be described. We also intend to discuss the emerging nano-based approaches suitable to be used as imaging techniques and as cancer treatment options.

MRI tracking stem cells transplantation for coronary heart disease

Cardiovascular disease is the leading cause of mortality worldwide. Stem cell transplantation has become a new treatment option for cardiovascular disease because the stem cells are able to migrate to damaged cardiac tissue, repair the myocardial infarction area and ultimately reduce the role of the infarct-related mortality. Cardiac magnetic resonance imaging (MRI) is a new robust non-invasive imaging technique that can detect anatomical information and myocardial dysfunction, study the mechanism of stem cells therapy with superb spatial/temporal resolution, relatively safe contrast material and lack of radiation. This review describes the advantages and disadvantages of cardiac MRI applied in stem cells transplantation and discusses how to translate this technique into clinical therapy.

Sources of Data/Study Selection: Data from cross-sectional and prospective studies published between the years 2001-2013 on the topic were included. Data searches included both human and animal studies.

Data Extraction: The data was extracted from online resources of statistic reports, Pub med, THE MEDLINE, Google Scholar, Medical and Radiological journals.

Conclusion: MRI is an appealing technique for cell trafficking depicting engraftment, differentiation and survival.

Tracking immune cells in vivo using magnetic resonance imaging

The increasing complexity of in vivo imaging technologies, coupled with the development of cell therapies, has fuelled a revolution in immune cell tracking in vivo. Powerful magnetic resonance imaging (MRI) methods are now being developed that use iron oxide- and ¹⁹F-based probes. These MRI technologies can be used for image-guided immune cell delivery and for the visualization of immune cell homing and engraftment, inflammation, cell physiology and gene expression. MRI-based cell tracking is now also being applied to evaluate therapeutics that modulate endogenous immune cell recruitment and to monitor emerging cellular immunotherapies. These recent uses show that MRI has the potential to be developed in many applications to follow the fate of immune cells in vivo.