NRG1 PLGA MP locally induce macrophage polarisation toward a regenerative phenotype in the heart after acute myocardial infarction

Neuregulin-1β Improves Uremic Cardiomyopathy and Renal Dysfunction in Rats

Chronic kidney disease is a global health problem affecting 10% to 12% of the population. Uremic cardiomyopathy is often characterized by left ventricular hypertrophy, fibrosis, and diastolic dysfunction. Dysregulation of neuregulin-1β signaling in the heart is a known contributor to heart failure. The systemically administered recombinant human neuregulin-1β for 10 days in our 5/6 nephrectomy-induced model of chronic kidney disease alleviated the progression of uremic cardiomyopathy and kidney dysfunction in type 4 cardiorenal syndrome. The currently presented positive preclinical data warrant clinical studies to confirm the beneficial effects of recombinant human neuregulin-1β in patients with chronic kidney disease.

Nanoparticles Targeting the Molecular Pathways of Heart Remodeling and Regeneration

Cardiovascular diseases are the main cause of death worldwide, a trend that will continue to grow over the next decade. The heart consists of a complex cellular network based mainly on cardiomyocytes, but also on endothelial cells, smooth muscle cells, fibroblasts, and pericytes, which closely communicate through paracrine factors and direct contact. These interactions serve as valuable targets in understanding the phenomenon of heart remodeling and regeneration. The advances in nanomedicine in the controlled delivery of active pharmacological agents are remarkable and may provide substantial contribution to the treatment of heart diseases. This review aims to summarize the main mechanisms involved in cardiac remodeling and regeneration and how they have been applied in nanomedicine.

Nrg1/ErbB signaling-mediated regulation of fibrosis after myocardial infarction

Appropriate fibrotic tissue formation after myocardial infarction (MI) is crucial to the maintenance of the heart's structure. M2-like macrophages play a vital role in post-MI fibrosis by activating cardiac fibroblasts. Because the mechanism by which post-MI cardiac fibrosis is regulated is not fully understood, we investigated, in vitro and in vivo, the cellular and molecular mechanisms of post-MI fibrotic tissue formation, especially those related to the regulation of cellular senescence and apoptosis. CD206⁺ F4/80⁺ CD11b⁺ M2-like macrophages collected from mouse hearts on post-MI day 7 showed increased expression of neuregulin 1 (Nrg1). Nrg1 receptor epidermal growth factor receptors ErbB2 and ErbB4 were expressed on cardiac fibroblasts in the infarct area. M2-like macrophage-derived Nrg1 suppressed both hydrogen peroxide-induced senescence and apoptosis of fibroblasts, whereas blockade of ErbB function significantly accelerated both processes. M2-like macrophage-derived Nrg1/ErbB/PI3K/Akt signaling, shown to be related to anti-senescence, was activated in damaged cardiac fibroblasts. Interestingly, systemic blockade of ErbB function in MI model mice enhanced senescence and apoptosis of cardiac fibroblasts and exacerbated inflammation. Further, increased accumulation of M2-like macrophages resulted in excessive post-MI progression of fibrosis in mice hearts. The molecular mechanism underlying the regulation of fibrotic tissue formation in the infarcted myocardium was shown in part to be attenuation of apoptosis and senescence of cardiac fibroblasts by the activation of Nrg1/ErbB/PI3K/Akt signaling. M2-like macrophage-mediated regulation of Nrg1/ErbB signaling has a substantial effect on fibrotic tissue formation in the infarcted adult mouse heart and is critical for suppressing the progression of senescence and apoptosis of cardiac fibroblasts.

The pro-inflammatory response of macrophages regulated by acid degradation products of poly(lactide-co-glycolide) nanoparticles

Poly(lactide-co-glycolide) (PLGA) shows great potentials in biomedical applications, in particular with the field of biodegradable implants and control release technologies. However, there are few systematic and detailed studies on the influence of PLGA degradation behavior on the immunogenicity. In this study, in order to develop a method for dynamically assessing the immunological response of PLGA throughout the implantation process, PLGA particles are fabricated using an o/w single-emulsion method. The physicochemical characterizations of the prepared PLGA particles during in vitro hydrolytic degradation are investigated. Then, a series of immunological effects triggered by PLGA by-products formed with degradation process are evaluated, including cell viability, apoptosis, polarization and inflammatory reaction. THP-1 human cell line is set as in vitro cell model. Our results show that PLGA degradation-induced acid environment decreases cell viability and increases cell apoptosis, which is a potential factor affecting cell function. In particular, the macrophages exhibit up-regulations in both M1 subtype related surface markers and pro-inflammatory cytokines with the degradation process of PLGA, which indicates the degradation products of PLGA can convert macrophages to the pro-inflammatory (M1) polarization state. All these findings provide the mechanism of PLGA-induced inflammation and lay the foundation for the design of next-generation PLGA-based biomaterials endowed with immunomodulatory functions.

De novo Drug Delivery Modalities for Treating Damaged Hearts: Current Challenges and Emerging Solutions

Cardiovascular disease (CVD) is the leading cause of mortality, resulting in approximately one-third of deaths worldwide. Among CVD, acute myocardial infarctions (MI) is the leading cause of death. Current treatment modalities for treating CVD have improved over the years, but the demand for new and innovative therapies has been on the rise. The field of nanomedicine and nanotechnology has opened a new paradigm for treating damaged hearts by providing improved drug delivery methods, specifically targeting injured areas of the myocardium. With the advent of innovative biomaterials, newer therapeutics such as growth factors, stem cells, and exosomes have been successfully delivered to the injured myocardial tissue, promoting improvement in cardiac function. This review focuses on three major drug delivery modalities: nanoparticles, microspheres, and hydrogels, and their potential for treating damaged hearts following an MI.

Drug delivery to macrophages: A review of targeting drugs and drug carriers to macrophages for inflammatory diseases

Macrophages play a key role in defending against foreign pathogens, healing wounds, and regulating tissue homeostasis. Driving this versatility is their phenotypic plasticity, which enables macrophages to respond to subtle cues in tightly coordinated ways. However, when this coordination is disrupted, macrophages can aid the progression of numerous diseases, including cancer, cardiovascular disease, and autoimmune disease. The central link between these disorders is aberrant macrophage polarization, which misguides their functional programs, secretory products, and regulation of the surrounding tissue microenvironment. As a result of their important and deterministic roles in both health and disease, macrophages have gained considerable attention as targets for drug delivery. Here, we discuss the role of macrophages in the initiation and progression of various inflammatory diseases, summarize the leading drugs used to regulate macrophages, and review drug delivery systems designed to target macrophages. We emphasize strategies that are approved for clinical use or are poised for clinical investigation. Finally, we provide a prospectus of the future of macrophage-targeted drug delivery systems.