Plasma Separation by Centrifugation and Subsequent Plasma Filtration: Impact on Survival in a Pig Model of Sepsis

Efficacy of hemofiltration with PEPA membrane for IL-6 removal in a rat sepsis model

Recently, intensive care physicians have focused on continuous hemodiafiltration with a cytokine-adsorbing hemofilter in the treatment of sepsis. We aimed to establish extracorporeal circulation in a rat sepsis model to evaluate the cytokine removal properties of mini-modules using two types of membrane materials. Rats were divided into polyester polymer alloy (PEPA) and cellulose triacetate (CTA) groups as membrane materials of mini-modules. One hour after 0.1 mg/kg of lipopolysaccharide administration, continuous hemofiltration (CHF) was started in each group. Plasma interleukin-6 (IL-6), an important mediator of sepsis, was measured over time during hemofiltration. The peak IL-6 concentration in PEPA group was approximately 13,000 pg/mL, in comparison to approximately 31,000 pg/mL in CTA group. IL-6 clearance in PEPA group was much more than CTA group. Since IL-6 was not detected in the filtrate in PEPA group, it was considered that IL-6 was adsorbed to the membrane. In conclusion, our results suggest that CHF with PEPA hemofilter can be suitable for removing IL-6 from the blood stream efficiently.

Lessons learned from the porcine CARPA model: constant and variable responses to different nanomedicines and administration protocols

Pigs provide a sensitive and quantitative animal model of complement (C) activation-related pseudoallergy (CARPA) caused by liposomes and a wide range of nanoparticulate drugs or drug nanocarriers (nanomedicines). The tetrad of symptoms (hemodynamic, hematological, laboratory and skin changes) that arise within minutes after i.v. injection of reactogenic nanomedicines (RNMs) are highly reproducible among different pigs but the presence, direction and relative severity of symptoms are very different with different RNMs and their administration schedule. Bolus administration of RNMs usually trigger pulmonary hypertension with or without various degrees of systemic hyper- or hypotension, tachy-or bradycardia, arrhythmia, blood cell and inflammatory mediator changes and skin rash. These reactions can be rapid or protracted, and fully tachyphylactic, semi-tachyphylactic or non-tachyphylactic. Slow infusion usually diminishes the reactions and/or entail delayed, protracted and less severe hemodynamic and other changes. The goal of this review is to present some technical details of the porcine CARPA model, point out its constant and variable parameters, show examples of different reactions, highlight the unique features and capabilities of the model and evaluate its utility in preclinical safety assessment. The information obtained in this model enables the understanding of the complex pathomechanism of CARPA involving simultaneous anaphylatoxin and inflammatory mediator actions at multiple sites in different organs.