Spleen data: Cerium oxide nanoparticles attenuate polymicrobial sepsis induced spenic damage in male Sprague Dawley rats

The Impressive Anti-Inflammatory Activity of Cerium Oxide Nanoparticles: More than Redox?

Cerium oxide nanoparticles (CNPs) are biocompatible nanozymes exerting multifunctional biomimetic activities, including superoxide dismutase (SOD), catalase, glutathione peroxidase, photolyase, and phosphatase. SOD- and catalase-mimesis depend on Ce3+/Ce4+ redox switch on nanoparticle surface, which allows scavenging the most noxious reactive oxygen species in a self-regenerating, energy-free manner. As oxidative stress plays pivotal roles in the pathogenesis of inflammatory disorders, CNPs have recently attracted attention as potential anti-inflammatory agents. A careful survey of the literature reveals that CNPs, alone or as constituents of implants and scaffolds, strongly contrast chronic inflammation (including neurodegenerative and autoimmune diseases, liver steatosis, gastrointestinal disorders), infections, and trauma, thereby ameliorating/restoring organ function. By general consensus, CNPs inhibit inflammation cues while boosting the pro-resolving anti-inflammatory signaling pathways. The mechanism of CNPs' anti-inflammatory effects has hardly been investigated, being rather deductively attributed to CNP-induced ROS scavenging. However, CNPs are multi-functional nanozymes that exert additional bioactivities independent from the Ce3+/Ce4+ redox switch, such as phosphatase activity, which could conceivably mediate some of the anti-inflammatory effects reported, suggesting that CNPs fight inflammation via pleiotropic actions. Since CNP anti-inflammatory activity is potentially a pharmacological breakthrough, it is important to precisely attribute the described effects to one or another of their nanozyme functions, thus achieving therapeutic credibility.

Fabrication of a curcumin encapsulated bioengineered nano-cocktail formulation for stimuli-responsive targeted therapeutic delivery to enhance anti-inflammatory, anti-oxidant, and anti-bacterial properties in sepsis management

This study aimed to fabricate an eco-friendly functionalized chitosan (CS) nanocarrier to establish a pH-responsive drug delivery system for the treatment of sepsis. Curcumin (Cur) and cerium oxide (CeO₂) were loaded onto an octenylsuccinic anhydride (OSA)-functionalized CS nanoformulation (Cur@Ce/OCS) to achieve an effective nanocarrier (NC) for sepsis treatment. The physicochemical characteristics of the developed nanocarriers were determined using various characterization techniques. The developed CeO₂-OCS nanoformulation has been showed effective anti-bacterial activity (∼97%) against G⁺ and G^- bacterial pathogens, and also have improved drug loading (94% ± 2), and encapsulation efficiency (89.8% ± 1.5), with uniform spherical particles having an average diameter of between 100 and 150 nm. The in vivo experimental results establish that Cur-loaded Ce/OCS NPs could have enhanced therapeutic potential against lung infection model by reducing bacterial burden and extensively decreasing inflammatory responses in sepsis model. Additionally, we determined the in vivo biosafety of the nanoformulations by histological observation of different mouse organs (heart, liver, spleen, and kidney), and observed no signs of toxicity in the treatment groups. The findings of this study clearly demonstrate the therapeutic potential of pH-sensitive nanoplatforms in the management of infectious sepsis.

How Does Immunomodulatory Nanoceria Works? ROS and Immunometabolism

Dysregulation of the immune system is associated with an overproduction of metabolic reactive oxygen species (ROS) and consequent oxidative stress. By buffering excess ROS, cerium oxide (CeO₂) nanoparticles (NPs) (nanoceria) not only protect from oxidative stress consequence of inflammation but also modulate the immune response towards inflammation resolution. Immunomodulation is the modulation (regulatory adjustment) of the immune system. It has natural and human-induced forms, and it is part of immunotherapy, in which immune responses are induced, amplified, attenuated, or prevented according to therapeutic goals. For decades, it has been observed that immune cells transform from relative metabolic quiescence to a highly active metabolic state during activation(1). These changes in metabolism affect fate and function over a broad range of timescales and cell types, always correlated to metabolic changes closely associated with mitochondria number and morphology. The question is how to control the immunochemical potential, thereby regulating the immune response, by administering cellular power supply. In this regard, immune cells show different general catabolic modes relative to their activation status, linked to their specific functions (maintenance, scavenging, defense, resolution, and repair) that can be correlated to different ROS requirements and production. Properly formulated, nanoceria is highly soluble, safe, and potentially biodegradable, and it may overcome current antioxidant substances limitations and thus open a new era for human health management.