Top-down functionalization of nanoparticles with cellular membranes imparts nanoparticles with enhanced bio-interfacing capabilities. Initial methods for membrane coating involved physical co-extrusion of nanoparticles and membrane vesicles through a porous membrane; however, recent works employ sonication as the disruptive force to reform membranes around the surface of nanoparticles. Although sonication is widely used, there remains a paucity of information on the effects of sonication variables on coating efficiency, leading to inconsistent membrane coating across studies. In this work, we present a systematic analysis of the sonication parameters that influence the membrane coating. The results showed that sonication amplitude, time, temperature, membrane ratio, sample volume, and density need to be considered in order to optimize membrane coating of polymeric nanoparticles.

Non-parenteral drug delivery systems using biomaterials have advantages over traditional parenteral strategies. For ocular and intranasal delivery, nanoparticulate systems must bind to and permeate through mucosal epithelium and other biological barriers. The incorporation of mucoadhesive and permeation-enhancing biomaterials such as chitosan facilitate this, but tend to increase the size and polydispersity of the nanoparticles, making practical optimization and implementation of mucoadhesive nanoparticle formulations a challenge. In this study, we adjusted key poly(lactic-co-glycolic) acid (PLGA) nanoparticle formulation parameters including the organic solvent and co-solvent, the concentration of polymer in the organic phase, the composition of the aqueous phase, the sonication amplitude, and the inclusion of chitosan in the aqueous phase. By doing so, we prepared four statistically unique size groups of PLGA NPs and equally-sized chitosan-PLGA NP counterparts. We loaded simvastatin, a candidate for novel ocular and intranasal delivery systems, into the nanoparticles to investigate the effects of size and surface modification on drug loading and release, and we quantified size- and surface-dependent changes in mucoadhesion in vitro. These methods and findings will contribute to the advancement of mucoadhesive nanoformulations for ocular and nose-to-brain drug delivery.

Oxidative stress is a known contributor to the progression of dry eye disease pathophysiology, and previous studies have shown that antioxidant intervention is a promising therapeutic approach to reduce the disease burden and slow disease progression. In this study, we evaluated the pharmacological efficacy of the naturally occurring prenylated chalconoid, xanthohumol, in preclinical models for dry eye disease. Xanthohumol acts by promoting the transcription of phase II antioxidant enzymes. In this study, xanthohumol prevented tert-butyl hydroperoxide-induced loss of cell viability in human corneal epithelial (HCE-T) cells in a dose-dependent manner and resulted in a significant increase in expression of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2), the master regulator of phase II endogenous antioxidant enzymes. Xanthohumol-encapsulating poly(lactic-co-glycolic acid) nanoparticles (PLGA NP) were cytoprotective against oxidative stress in vitro, and significantly reduced ocular surface damage and oxidative stress-associated DNA damage in corneal epithelial cells in the mouse desiccating stress/scopolamine model for dry eye disease in vivo. PLGA NP represent a safe and efficacious drug delivery vehicle for hydrophobic small molecules to the ocular surface. Optimization of NP-based antioxidant formulations with the goal to minimize instillation frequency may represent future therapeutic options for dry eye disease and related ocular surface disease.

Guillain-Barré syndrome (GBS) is a devastating autoimmune disease of the peripheral nervous system (PNS) with limited treatment options. Several studies have shown attenuation of the well-characterized GBS preclinical experimental autoimmune neuritis (EAN) model with systemically administered therapeutic compounds via anti-inflammatory or immunomodulatory mechanisms. Despite this, clinical advancement of these findings is limited by dosing that is not translatable to humans or is associated with off-target and toxic effects. This is due, in part, to the blood-nerve barrier (BNB), which restricts access of the circulation to peripheral nerves. However, during acute neuroinflammation, the normally restrictive BNB exhibits increased vascular permeability and enables immune cell infiltration. This may offer a unique window to access the otherwise restricted peripheral nerve microenvironment for therapeutic delivery. Here, we assessed the degree to which BNB permeability and immune cell infiltration over the course of EAN enables accumulation of circulating nanoparticles. We found that at disease stages defined by distinct clinical scores and pathology (onset, effector phase, and peak of EAN severity), intravenously administered small molecules and nanoparticles ranging from 50 to 150 nm can permeate into the endoneurium from the endoneurial vasculature in a size- and stage-dependent manner. This permeation occurs uniformly in both sciatic nerves and in proximal and distal regions of the nerves. We propose that this nerve targeting enabled by pathology serves as a platform by which potential therapies for GBS can be reevaluated and investigated preclinically in nanoparticle delivery systems.

Lower extremity peripheral arterial disease (PAD) is the atherosclerotic obstruction of the lower extremity arteries that can lead to walking impairment, non-healing open wounds, gangrene or limb loss. It is estimated that PAD affects greater than 200 million people worldwide and is associated with advanced age, tobacco use, diabetes, hypertension, and hypercholesterolemia. Initial management of PAD involves risk factor modification and pharmacologic strategies, including the implementation of statin therapy. Statins, the most commonly used cholesterol lowering medications, also have beneficial pleiotropic (cholesterol independent) effects including improved patency rates from vascular reconstruction, decreased risk of stroke, myocardial infarction and improved survival. In this chapter, we will discuss the relevant clinical trials, prospective observation and retrospective studies that exemplify the effect of statins on PAD. We will then focus on statin’s cellular effects on endothelial and vascular smooth muscle cell function by examining effects on plaque progression, intimal hyperplasia, re-endothelialization, and angiogenesis/arteriogenesis.

Background: Statins have beneficial pleiotropic effects, including reducing intimal hyperplasia (IH), but off-target effects remain a concern. Here, we tested the hypothesis that chitosan-functionalized polymeric nanoparticles (NPs) loaded with simvastatin (SL-cNPs) would (1) readily associate with endothelial cells (ECs) and vascular smooth muscle cells (VSMCs); (2) affect EC and VSMC function; and (3) reduce IH compared to systemic simvastatin. Methods: Human aortic ECs and VSMCs were cultured with fluorescently labeled SL-cNPs. The association of SL-cNPs was assessed by immunostaining and flow cytometry. The effect of SL-cNPs, empty cNPs (E-cNPs), and free simvastatin on cells was determined using qRT-PCR for RhoA and RhoB. Carotid artery balloon-injured rats were treated intraoperatively with intraluminal saline, E-cNPs, low- or high-dose SL-cNPs, periadventitial high-dose SL-cNPs, or with pre- and post-operative oral simvastatin plus intraoperative intraluminal saline or low-dose SL-cNPs. Rats were euthanized (day 14) and IH was quantified. Results: SL-cNPs readily associated with ECs and VSMCs. Low- and high-dose SL-cNPs induced significant increases in EC and VSMC RhoA gene expression. High-dose SL-cNPs induced a significant increase in EC RhoB expression, while free simvastatin and low- and high-dose SL-cNPs significantly increased RhoB expression in VSMCs. In vivo, oral simvastatin plus intraluminal SL-cNPs significantly reduced IH compared to controls. Conclusions: cNPs can be used as a vehicle to locally deliver statins to vascular cells. However, other NP formulations may be preferential for IH reduction given only the combination of oral simvastatin and SL-cNPs effectively reduced IH.