Inhalable Nitric Oxide Delivery Systems for Pulmonary Arterial Hypertension Treatment.

Pulmonary arterial hypertension (PAH) is a severe medical condition characterized by elevated blood pressure in the pulmonary arteries. Nitric oxide (NO) is a gaseous signaling molecule with potent vasodilator effects; however, inhaled NO is limited in clinical practice because of the need for tracheal intubation and the toxicity of high NO concentrations. In this study, inhalable NO-releasing microspheres (NO inhalers) are fabricated to deliver nanomolar NO through a nebulizer. Two NO inhalers with distinct porous structures are prepared depending on the molecular weights of NO donors. It is confirmed that pore formation can be controlled by regulating the migration of water molecules from the external aqueous phase to the internal aqueous phase. Notably, open porous NO inhalers (OPNIs) can deliver NO deep into the lungs through a nebulizer. Furthermore, OPNIs exhibit vasodilatory and anti-inflammatory effects via sustained NO release. In conclusion, the findings suggest that OPNIs with highly porous structures have the potential to serve as tools for PAH treatment.

Zwitterionic Inhaler with Synergistic Therapeutics for Reprogramming of M2 Macrophage to Pro-Inflammatory Phenotype.

Myriad lung diseases are life threatening and macrophages play a key role in both physiological and pathological processes. Macrophages have each pro-/anti-inflammatory phenotype, and each lung disease can be aggravated by over-polarized macrophage. Therefore, development of a method capable of mediating the macrophage phenotype is one of the solutions for lung disease treatment. For mediating the phenotype of macrophages, the pulmonary delivery system (PDS) is widely used due to its advantages, such as high efficiency and accessibility of the lungs. However, it has a low drug delivery efficiency ironically because of the perfect lung defense system consisting of the mucus layer and airway macrophages. In this study, zwitterion-functionalized poly(lactide-co-glycolide) (PLGA) inhalable microparticles (ZwPG) are synthesized to increase the efficiency of the PDS. The thin layer of zwitterions formed on PLGA surface has high nebulizing stability and show high anti-mucus adhesion and evasion of macrophages. As a reprogramming agent for macrophages, ZwPG containing dexamethasone (Dex) and pirfenidone (Pir) are treated to over-polarized M2 macrophages. As a result, a synergistic effect of Dex/Pir induces reprogramming of M2 macrophage to pro-inflammatory phenotypes.

A Nanocoating Co-Localizing Nitric Oxide and Growth Factor onto Individual Endothelial Cells Reveals Synergistic Effects on Angiogenesis.

The delivery of nitric oxide (NO)-an intrinsic cellular signaling molecule-is promising for disease treatment, in particular to vascular diseases, due to its endothelial-derived inherent nature. The limited diffusion distance of labile NO prompts researchers to develop various carriers and targeting methods for specific sites. In contrast to the apoptotic effect of NO, such as anticancer, delivering low NO concentration at the desired targeting area is still intricate in a physiological environment. In this study, the layer-by-layer assembled nanocoating is leveraged to develop a direct NO delivery platform to individual endothelial cells (ECs). NO can be localized to individual ECs via S-nitrosothiol-bound polyacrylic acid which is a polymer directly providing an endothelial-like constant level of NO. To increase angiogenic activation along with NO, VEGF is additionally applied to specific receptors on the cell surface. Notably, the survival and proliferation of ECs are significantly increased by a synergistic effect of NO and VEGF co-localized via nanocoating. Furthermore, the nanocoating remarkably promoted cell migration and tubule formation-prerequisites of angiogenesis. The proposed unique technology based on nanocoating demonstrates great potential for conferring desired angiogenic functions to individual ECs through efficient NO delivery.

In vitro toxicity from a physical perspective of polyethylene microplastics based on statistical curvature change analysis.

Microplastics which are gradually and randomly decompose into small fragment by exposure of physical and biological external stress are emerging as a significant threat to the all the environments. Here, we have demonstrated the in vitro toxicity of microplastics of two different shapes. To minimize the chemical effect, polyethylene (PE), was used. PE microplastics with two different shapes were prepared, high-density PE microbeads and irregularly ground low-density PE from bulk pellets. It is hypothesized that morphological characteristics and concentration of PE microplastics could affect cellular viability, immunity, and lysis. To quantify the randomness of the microplastic shape, the edge patterns of the generated PE microplastics were converted into numerical values and analyzed using a statistical method. A 10-fold difference in curvature value was observed between microbeads and ground microfragments. To correlate shape differences to toxicology, cells were exposed to PE microplastics on the demand of toxicology studies. We found that the higher concentration and rough structure were associated with the toxicity of plastics toward cells, pro-inflammatory cytokine release, and hemolysis, even though PE is buoyant onto medium. The PE microbeads did not exhibit severe cytotoxicity at any of the tested concentrations, but induced immune and hemolysis responses at high concentrations. When comparing the toxicity of different shapes of PE microplastics, we confirmed by statistical analysis that irregular-shape plastics with sharp edges and higher curvature differences may adversely affect cells, further having possibility to human toxicity in real environment.

Controlled Nitric Oxide Release Using Poly(lactic-co-glycolic acid) Nanoparticles for Anti-Inflammatory Effects.

Nitric oxide (NO) plays a key role in several physiological functions such as inflammatory responses and immune regulation. However, despite its beneficial functions, the short half-life and diffusion radius limit NO availability in biomedical applications. Hence, controlled release is important to achieve the desired therapeutic effects with exogenous NO delivery. In this study, we fabricated a poly(lactic-co-glycolic acid) (PLGA)-based NO delivery system to release NO in a sustained manner under physiological conditions. To prevent an initial burst release, branched polyethylenimine diazeniumdiolate (BPEI/NONOate), a pH-responsive NO donor, was encapsulated into the hydrophilic core of PLGA nanoparticles. Furthermore, low concentrations of NO released at a consistent level via a stabilization effect obtained as amine groups of BPEI/NONOate interacted with the nearby NONOate. Using the controlled-release profiles, we successfully regulated the inflammatory response in lipopolysaccharide-stimulated peripheral blood mononuclear cells. This work demonstrates the potential of a NO delivery carrier in the regulation of inflammation.

In vitro chemical and physical toxicities of polystyrene microfragments in human-derived cells.

With the increase in plastic production, a variety of toxicological studies on microplastics have been conducted as microplastics can be accumulated in the human body and cause unknown disease. However, previous studies have mainly assessed the toxicity of sphere-type microbeads, which may differ from randomly-shaped microplastics in a real environment. Here, we conducted in vitro toxicology analysis for randomly-shaped microplastics based on the hypotheses that (1) physical cytotoxicity is affected by nano-/micro-size roughness in polystyrene (PS) microfragments and (2) chemical toxicity is caused by chemical reagents from microplastics. We confirmed that the PS microfragments increased the acute inflammation of immune cells 20 times than control, the production of reactive oxygen species, and cell death of fibroblasts and cancer cells by releasing chemical reagents. In addition, when the PS microfragments were in direct contact with fibroblasts and red blood cells, the physical stress caused by them resulted in lactose dehydrogenase and hemoglobin release, respectively, due to cell membrane damage and hemolysis. This phenomenon was amplified when the concentration and roughness of the microfragments increased. Moreover, we quantitatively analyzed roughness differences between microplastics, which revealed a strong relationship between the physical damage of cells and the roughness of microplastics.