Liposomal prednisolone promotes macrophage lipotoxicity in experimental atherosclerosis.

Atherosclerosis is a lipid-driven inflammatory disease, for which nanomedicinal interventions are under evaluation. Previously, we showed that liposomal nanoparticles loaded with prednisolone (LN-PLP) accumulated in plaque macrophages, however, induced proatherogenic effects in patients. Here, we confirmed in low-density lipoprotein receptor knockout (LDLr(-/-)) mice that LN-PLP accumulates in plaque macrophages. Next, we found that LN-PLP infusions at 10mg/kg for 2weeks enhanced monocyte recruitment to plaques. In follow up, after 6weeks of LN-PLP exposure we observed (i) increased macrophage content, (ii) more advanced plaque stages, and (iii) larger necrotic core sizes. Finally, in vitro studies showed that macrophages become lipotoxic after LN-PLP exposure, exemplified by enhanced lipid loading, ER stress and apoptosis. These findings indicate that liposomal prednisolone may paradoxically accelerate atherosclerosis by promoting macrophage lipotoxicity. Hence, future (nanomedicinal) drug development studies are challenged by the multifactorial nature of atherosclerotic inflammation.

Pharmaceutical development and preclinical evaluation of a GMP-grade anti-inflammatory nanotherapy.

The present study describes the development of a good manufacturing practice (GMP)-grade liposomal nanotherapy containing prednisolone phosphate for the treatment of inflammatory diseases. After formulation design, GMP production was commenced which yielded consistent, stable liposomes sized 100nm±10nm, with a prednisolone phosphate (PLP) incorporation efficiency of 3%-5%. Pharmacokinetics and toxicokinetics of GMP-grade liposomal nanoparticles were evaluated in healthy rats, which were compared to daily and weekly administration of free prednisolone phosphate, revealing a long circulatory half-life with minimal side effects. Subsequently, non-invasive multimodal clinical imaging after liposomal nanotherapy's intravenous administration revealed anti-inflammatory effects on the vessel wall of atherosclerotic rabbits. The present program led to institutional review board approval for two clinical trials with patients with atherosclerosis. FROM THE CLINICAL EDITOR: In drug discovery, bringing production to industrial scale is an essential process. In this article the authors describe the development of an anti-inflammatory nanoparticle according to good manufacturing practice. As a result, this paves the way for translating laboratory studies to clinical trials in humans.

Prednisolone-containing liposomes accumulate in human atherosclerotic macrophages upon intravenous administration.

Drug delivery to atherosclerotic plaques via liposomal nanoparticles may improve therapeutic agents' risk-benefit ratios. Our paper details the first clinical studies of a liposomal nanoparticle encapsulating prednisolone (LN-PLP) in atherosclerosis. First, PLP's liposomal encapsulation improved its pharmacokinetic profile in humans (n=13) as attested by an increased plasma half-life of 63h (LN-PLP 1.5mg/kg). Second, intravenously infused LN-PLP appeared in 75% of the macrophages isolated from iliofemoral plaques of patients (n=14) referred for vascular surgery in a randomized, placebo-controlled trial. LN-PLP treatment did however not reduce arterial wall permeability or inflammation in patients with atherosclerotic disease (n=30), as assessed by multimodal imaging in a subsequent randomized, placebo-controlled study. In conclusion, we successfully delivered a long-circulating nanoparticle to atherosclerotic plaque macrophages in patients, whereas prednisolone accumulation in atherosclerotic lesions had no anti-inflammatory effect. Nonetheless, the present study provides guidance for development and imaging-assisted evaluation of future nanomedicine in atherosclerosis. FROM THE CLINICAL EDITOR: In this study, the authors undertook the first clinical trial using long-circulating liposomal nanoparticle encapsulating prednisolone in patients with atherosclerosis, based on previous animal studies. Despite little evidence of anti-inflammatory effect, the results have provided a starting point for future development of nanomedicine in cardiovascular diseases.