Beyond Vessel Diameters: Non-invasive Monitoring of Flow Patterns and Immune Cell Recruitment in Murine Abdominal Aortic Disorders by Multiparametric MRI

Brain peptides modified exosome-mediated drug delivery system for adriamycin-induced nephropathy treatment

Mitigation of adriamycin (ADR)-induced nephropathy remains a significant challenge in clinical management. Brain-targeted administration of losartan demonstrates comparable nephroprotective effects at a 1:500 concentration relative to gavage administration. This study established an exosome-based nano-delivery platform (ExoACP) to reduce drug dosage for alleviating ADR-induced nephropathy. The platform was rigorously tested for toxicity and blood-brain barrier penetration. Additionally, the role and possible mechanism of ExoACP-Los in alleviating ADR-induced nephropathy in mice were investigated. ExoACP showed enhanced penetration in brain microvascular endothelial cells, with a 7.20-fold increase in uptake. In the ADR model, ExoACP-Los exhibited anti-inflammatory and anti-fibrotic effects by downregulating the renin-angiotensin system, reducing extracellular matrix deposition by nearly half. These findings suggest ExoACP-Los can alleviate ADR-induced nephropathy by enhancing targeted drug delivery to the brain while reducing losartan. Overall, ExoACP holds significant potential for future clinical applications in chronic nephropathy.

Transient High Salt Intake Promotes T-Cell-Mediated Hypertensive Vascular Injury

BACKGROUND

Dietary high salt (HS) intake has a strong impact on cardiovascular diseases. Here, we investigated the link between HS-aggravated immune responses and the development of hypertensive vascular disease.

METHODS

ApolipoproteinE-deficient mice were transiently treated with HS (1% NaCl) via drinking water for 2 weeks, followed by a washout period, and subsequent Ang II (angiotensin II) infusion (1000 ng/kg per min for 10 days) to induce abdominal aortic aneurysms/dissections and inflammation.

RESULTS

While transient HS intake alone triggered nonpathologic infiltration of activated T cells into the aorta, subsequent Ang II infusion increased mortality and the incidence of abdominal aortic aneurysms/dissections and atherosclerosis compared with hypertensive control mice. There were no differences in blood pressure between both groups. In transient HS-treated hypertensive mice, the aortic injury was associated with increased inflammation, accumulation of neutrophils, monocytes, CD69+CD4+ T cells, as well as CD4+ and CD8+ memory T cells. Mechanistically, transient HS intake increased expression levels of aortic RORγt as well as splenic CD4+TH17 and CD8+TC1 T cells in Ang II-treated mice. Isolated aortas of untreated mice were incubated with supernatants of TH17, TH1, or TC1 cells polarized in vitro under HS or normal conditions which revealed that secreted factors of HS-differentiated TH17 and TC1 cells, but not TH1 cells accelerated endothelial dysfunction.

CONCLUSIONS

Our data suggest that transient HS intake induces a subclinical T-cell-mediated aortic immune response, which is enhanced by Ang II. We propose a 2-hit model, in which HS acts as a predisposing factor to enhance hypertension-induced TH17 and TC1 polarization and aortic disease.

Aortic aneurysm: pathophysiology and therapeutic options

Aortic aneurysm (AA) is an aortic disease with a high mortality rate, and other than surgery no effective preventive or therapeutic treatment have been developed. The renin-angiotensin system (RAS) is an important endocrine system that regulates vascular health. The ACE2/Ang-(1-7)/MasR axis can antagonize the adverse effects of the activation of the ACE/Ang II/AT1R axis on vascular dysfunction, atherosclerosis, and the development of aneurysms, thus providing an important therapeutic target for the prevention and treatment of AA. However, products targeting the Ang-(1-7)/MasR pathway still lack clinical validation. This review will outline the epidemiology of AA, including thoracic, abdominal, and thoracoabdominal AA, as well as current diagnostic and treatment strategies. Due to the highest incidence and most extensive research on abdominal AA (AAA), we will focus on AAA to explain the role of the RAS in its development, the protective function of Ang-(1-7)/MasR, and the mechanisms involved. We will also describe the roles of agonists and antagonists, suggest improvements in engineering and drug delivery, and provide evidence for Ang-(1-7)/MasR's clinical potential, discussing risks and solutions for clinical use. This study will enhance our understanding of AA and offer new possibilities and promising targets for therapeutic intervention.

Quantitative assessment of angioplasty-induced vascular inflammation with 19F cardiovascular magnetic resonance imaging

BACKGROUND

Macrophages play a pivotal role in vascular inflammation and predict cardiovascular complications. Fluorine-19 magnetic resonance imaging (19F MRI) with intravenously applied perfluorocarbon allows a background-free direct quantification of macrophage abundance in experimental vascular disease models in mice. Recently, perfluorooctyl bromide-nanoemulsion (PFOB-NE) was applied to effectively image macrophage infiltration in a pig model of myocardial infarction using clinical MRI scanners. In the present proof-of-concept approach, we aimed to non-invasively image monocyte/macrophage infiltration in response to carotid artery angioplasty in pigs using 19F MRI to assess early inflammatory response to mechanical injury.

METHODS

In eight minipigs, two different types of vascular injury were conducted: a mild injury employing balloon oversize angioplasty only (BA, n = 4) and a severe injury provoked by BA in combination with endothelial denudation (BA + ECDN, n = 4). PFOB-NE was administered intravenously three days after injury followed by 1H and 19F MRI to assess vascular inflammatory burden at day six. Vascular response to mechanical injury was validated using X-ray angiography, intravascular ultrasound and immunohistology in at least 10 segments per carotid artery.

RESULTS

Angioplasty was successfully induced in all eight pigs. Response to injury was characterized by positive remodeling with predominantly adventitial wall thickening and concomitant infiltration of monocytes/macrophages. No severe adverse reactions were observed following PFOB-NE administration. In vivo 19F signals were only detected in the four pigs following BA + ECDN with a robust signal-to-noise ratio (SNR) of 14.7 ± 4.8. Ex vivo analysis revealed a linear correlation of 19F SNR to local monocyte/macrophage cell density. Minimum detection limit of infiltrated monocytes/macrophages was estimated at approximately 410 cells/mm2.

CONCLUSIONS

In this proof-of-concept study, 19F MRI enabled quantification of monocyte/macrophage infiltration after vascular injury with sufficient sensitivity. This may provide the opportunity to non-invasively monitor vascular inflammation with MRI in patients after angioplasty or even in atherosclerotic plaques.

A Toolbox to Investigate the Impact of Impaired Oxygen Delivery in Experimental Disease Models

Impaired oxygen utilization is the underlying pathophysiological process in different shock states. Clinically most important are septic and hemorrhagic shock, which comprise more than 75% of all clinical cases of shock. Both forms lead to severe dysfunction of the microcirculation and the mitochondria that can cause or further aggravate tissue damage and inflammation. However, the detailed mechanisms of acute and long-term effects of impaired oxygen utilization are still elusive. Importantly, a defective oxygen exploitation can impact multiple organs simultaneously and organ damage can be aggravated due to intense organ cross-talk or the presence of a systemic inflammatory response. Complexity is further increased through a large heterogeneity in the human population, differences in genetics, age and gender, comorbidities or disease history. To gain a deeper understanding of the principles, mechanisms, interconnections and consequences of impaired oxygen delivery and utilization, interdisciplinary preclinical as well as clinical research is required. In this review, we provide a "tool-box" that covers widely used animal disease models for septic and hemorrhagic shock and methods to determine the structure and function of the microcirculation as well as mitochondrial function. Furthermore, we suggest magnetic resonance imaging as a multimodal imaging platform to noninvasively assess the consequences of impaired oxygen delivery on organ function, cell metabolism, alterations in tissue textures or inflammation. Combining structural and functional analyses of oxygen delivery and utilization in animal models with additional data obtained by multiparametric MRI-based techniques can help to unravel mechanisms underlying immediate effects as well as long-term consequences of impaired oxygen delivery on multiple organs and may narrow the gap between experimental preclinical research and the human patient.