Erythrocyte-Inspired Discoidal Polymeric Nanoconstructs carrying Tissue Plasminogen Activator for the Enhanced Lysis of Blood Clots

TL;DR

This study develops erythrocyte-inspired discoidal polymeric nanoconstructs carrying tPA, which significantly improve clot dissolution efficiency and safety in treating blood clots compared to free tPA and spherical nanoconstructs.

Contribution

The paper introduces a novel discoidal polymeric nanoconstructs platform for delivering tPA, enhancing its stability, circulation, and clot lysis performance over existing formulations.

Findings

tPA-DPNs protect tPA from degradation, maintaining over 70% activity after 3 hours.

tPA-DPNs dissolve clots faster than free tPA in microfluidic models.

In vivo, tPA-DPNs recanalize 90% of blood clots at low doses, outperforming free tPA.

Abstract

Tissue plasminogen activator (tPA) is the sole approved therapeutic molecule for the treatment of acute ischemic stroke. Yet, only a small percentage of patients could benefit from this life-saving treatment because of medical contraindications and severe side effects, including brain hemorrhage, associated with delayed administration. Here, a nano therapeutic agent is realized by directly associating the clinical formulation of tPA to the porous structure of soft discoidal polymeric nanoconstructs (tPA-DPNs). The porous matrix of DPNs protects tPA from rapid degradation, allowing tPA-DPNs to preserve over 70 % of the tPA original activity after 3 h of exposure to serum proteins. Under dynamic conditions, tPA-DPNs dissolve clots more efficiently than free tPA, as demonstrated in a microfluidic chip where clots are formed mimicking in vivo conditions. At 60 min post treatment initiation, the clot area reduces by half (57 + 8 %) with tPA-DPNs, whereas a similar result (56 + 21 %) is obtained only after 90 min for free tPA. In murine mesentery venules, the intravenous administration of 2.5 mg/kg of tPA-DPNs resolves almost 90 % of the blood clots, whereas a similar dose of free tPA successfully recanalize only about 40 % of the treated vessels. At about 1/10 of the clinical dose (1.0 mg/kg), tPA-DPNs still effectively dissolve 70 % of the clots, whereas free tPA works efficiently only on 16 % of the vessels. In vivo, discoidal tPA-DPNs outperform the lytic activity of 200 nm spherical tPA-coated nanoconstructs in terms of both percentage of successful recanalization events and clot area reduction. The conjugation of tPA with preserved lytic activity, the deformability and blood circulating time of DPNs together with the faster blood clot dissolution would make tPA-DPNs a promising nanotool for enhancing both potency and safety of thrombolytic therapies.