Toward a Theranostic Approach for the Brain Tumor Toxicity Profile of Polymer-Shelled Microbubbles.

in ACS omega by Gaio Paradossi, Fabio Domenici, Francesco Riccitelli, Rachel Grossman

TLDR

  • A novel theranostic device for brain tumor surgery has been developed, combining multimodal real-time intraoperative imaging with targeted drug delivery. Initial safety studies in rats suggest a low dose may be acceptable, paving the way for efficacy studies and potential clinical trials.

Abstract

The establishment of theranostic devices by combining multimodal real-time intraoperative imaging for brain tumor surgery with targeted drug delivery may provide therapeutic advantages for patients with malignant gliomas. Our group has recently developed a new generation of novel microbubbles (MBs), with an air core and a crosslinked poly(vinyl alcohol) shell, called PVA MBs. The PVA MB surface was engineered to support near-infrared (NIR) imaging with a fluorescence probe (C790) for the surgical microscope. The attachment to a cyclic pentapeptide containing the RGD sequence promotes active adhesion and direct targeting of endothelial tumor integrins. The conjugation of temozolomide (TMZ), an alkylating chemotherapy proven to be effective against malignant gliomas, provides a unique therapeutic advantage. The potential toxicity of this novel technology was assessed in rats by intravenous injections of two doses of naked MBs and MBs equipped with RGD for targeting tumor integrins, NIR fluorescence (CF790) for real-time visualization, and TMZ as a cytotoxic component, at two time points, 10 min and 7 days, for potential acute and chronic responses in rats [(1) MB, (2) MB-C790-RGD, and (3) MB-C790-RGD-TMZ]. No mortality occurred during the 7-day study period in any of the dosing groups. Decreased hemoglobin and hematocrit levels and increased triglyceride levels were noticed in the high-dose naked MBs and MBs-CF790-RGD groups. These findings may be associated with their enlarged spleen and liver, observed during necropsy. Histopathology examination in the high-dose animals showed the development of treatment-related changes seen mostly 7 days post dosing, consisting of granulomatous inflammation and foreign body reaction. Accordingly, we concluded that the low-dose tested items appeared to be safe. The results allow us to proceed with planning for an efficacy study before making the first attempt to use this technology in clinical practice.

Overview

  • The study aims to develop a novel theranostic device for brain tumor surgery combining multimodal real-time intraoperative imaging with targeted drug delivery.
  • The device uses novel microbubbles engineered with a poly(vinyl alcohol) shell and near-infrared imaging properties, conjugated with temozolomide, a chemotherapy medication.
  • The study assesses the potential toxicity of this technology in rats, with a focus on acute and chronic responses to determine its safety before clinical trials.

Comparative Analysis & Findings

  • The findings suggest that the low-dose tested items appear to be safe, with no mortality observed during the 7-day study period.
  • However, increased triglyceride levels, decreased hemoglobin and hematocrit levels, and enlargement of the spleen and liver were noted in the high-dose naked MBs and MBs-CF790-RGD groups.
  • Histopathology examination revealed granulomatous inflammation and foreign body reaction in the high-dose animals, indicating treatment-related changes.

Implications and Future Directions

  • The results enable the planning of an efficacy study before attempting to use this technology in clinical practice.
  • Future research should focus on optimizing the dose and duration of treatment to minimize adverse effects while maintaining therapeutic efficacy.
  • The development of this technology has the potential to revolutionize brain tumor surgery, providing a novel approach for targeted therapy and real-time imaging.
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