Search

Reperfusion injuries after a period of cardiac ischemia are known to lead to pathological modifications or even death. Among the different therapeutic options proposed, adenosine, a small molecule with platelet anti-aggregate and anti-inflammatory properties, has shown encouraging results in clinical trials. However, its clinical use is severely limited because of its very short half-life in the bloodstream. To overcome this limitation, we have proposed a strategy to encapsulate adenosine in squalene-based nanoparticles (NPs), a biocompatible and biodegradable lipid. Thus, the aim of this study was to assess, whether squalene-based nanoparticles loaded with adenosine (SQAd NPs) were cardioprotective in a preclinical cardiac ischemia/reperfusion model. Obtained SQAd NPs were characterized in depth and further evaluated in vitro. The NPs were formulated with a size of about 90 nm and remained stable up to 14 days at both 4 °C and room temperature. Moreover, these NPs did not show any signs of toxicity, neither on HL-1, H9c2 cardiac cell lines, nor on human PBMC and, further retained their inhibitory platelet aggregation properties. In a mouse model with experimental cardiac ischemia-reperfusion, treatment with SQAd NPs showed a reduction of the area at risk, as well as of the infarct area, although not statistically significant. However, we noted a significant reduction of apoptotic cells on cardiac tissue from animals treated with the NPs. Further studies would be interesting to understand how and through which mechanisms these nanoparticles act on cardiac cells.

A large variety of nanoparticle-based delivery systems have become increasingly important for diagnostic and/or therapeutic applications. Yet, the numerous physical and chemical parameters that influence both the biological and colloidal properties of nanoparticles remain poorly understood. This complicates the ability to reliably produce and deliver well-defined nanocarriers which often leads to inconsistencies, conflicts in the published literature and, ultimately, poor translation to the clinics. A critical issue lies in the challenge of scaling-up nanomaterial synthesis and formulation from the lab to industrial scale while maintaining control over their diverse properties. Studying these phenomena early on in the development of a therapeutic agent often requires partnerships between the public and private sectors which are hard to establish. In this study, through the particular case of squalene-adenosine nanoparticles, we reported on the challenges encountered in the process of scaling-up nanomedicines synthesis. Here, squalene (the carrier) was functionalized and conjugated to adenosine (the active drug moiety) at an industrial scale in order to obtain large quantities of biocompatible and biodegradable nanoparticles. After assessing nanoparticle batch-to-batch consistency, we demonstrated that the presence of squalene analogs resulting from industrial scale-up may influence several features such as size, surface charge, protein adsorption, cytotoxicity and crystal structure. These analogs were isolated, characterized by multiple stage mass spectrometry, and their influence on nanoparticle properties further evaluated. We showed that slight variations in the chemical profile of the nanocarrier's constitutive material can have a tremendous impact on the reproducibility of nanoparticle properties. In a context where several generics of approved nanoformulated drugs are set to enter the market in the coming years, characterizing and solving these issues is an important step in the pharmaceutical development of nanomedicines., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)