Focused ultrasound combined with drug-loaded microbubbles suppresses ictal spikes in kainic acid-induced epileptic animals.
Authors: Wu PH, Chien ME, Wu YJ, Fan CH
Current epilepsy treatments include anti-seizure medications (ASMs), surgical interventions, and neuromodulation. However, achieving precise, non-invasive seizure control continues to pose a significant clinical challenge. Transcranial-focused ultrasound (FUS) combined with microbubbles (MBs) has been employed to enhance localized chemotherapy drug delivery for brain tumors, yet its potential for improving ASMs delivery and modulating epileptic excitability has yet to be investigated. This study proposes a novel epilepsy treatment strategy using FUS with ASM- lacosamide-loaded MBs (L-MBs). Our results show that the accumulation of Lacosamide was significantly enhanced 8-fold in the targeted brain region (left CA1) in kainic acid-induced epileptic rats with L-MBs + 1-MHz FUS at 500 kPa, while heart tissue concentration was reduced by 55.6 % compared to direct IV administration. The most pronounced suppression of epileptic spikes was achieved at 500 kPa, resulting in a 91.5 % reduction in spike count within the initial 60 minutes post-treatment. This suppressive effect persisted for up to 180 minutes, with reductions of 82.2 % and 77.2 % observed during the 61-120 and 121-180 minutes intervals, respectively. Gamma power was significantly decreased in epileptic rats under 500 kPa FUS + L-MBs accompanied by the spike reduction. This minimally invasive, targeted delivery platform provides a promising alternative for managing drug-resistant focal epilepsy by enhancing focal ASM bioavailability and minimizing systemic adverse effects. Further preclinical and clinical studies are warranted to advance this strategy toward therapeutic application.
Introduction
Purpose
Drug delivery with BBB opening
Study Objective
To test whether focused ultrasound-activated lacosamide-loaded microbubbles can locally deliver lacosamide across the blood–brain barrier to suppress epileptic activity in a rat model while reducing systemic exposure.
Animal model / Human subject
Rat; strain: not specified; age: not specified; sex: male
Disease model
Epilepsy (kainic acid-induced epileptic rat model)
Targeted brain region(s)
Ca1
Target coordinates
AP: -5 mm, ML: 3.5 mm, DV: -3 mm
Cargo name and characteristics
Lacosamide (LCM) — a small-molecule anti-seizure medication (ASM); hydrophobic drug encapsulated via hydrophobic interactions into a delivery carrier for targeted brain delivery (enhanced 8-fold accumulation in left CA1 with FUS; reduced heart exposure by 55.6% versus IV)
Route of administration
intravenous
Outcomes and Safety
Summary of Outcomes
Focused ultrasound (FUS) with lacosamide-loaded microbubbles (L-MBs) produced an ~8-fold increase in drug accumulation in the targeted hippocampal CA1, reduced cardiac drug deposition by ~55.6%, markedly suppressed kainic acid–induced epileptic spikes (91.5% reduction in the first 60 min and sustained reductions up to 180 min) and lowered gamma power. FUS pressures of 100, 300, 500, and 700 kPa were tested; 500 kPa was identified as the optimal/successful setting (maximal BBB opening, highest local drug delivery and safe, effective seizure suppression), while 300 kPa yielded only minor BBB opening/insufficient delivery and 700 kPa caused tissue damage despite higher release.
Duration of biological effect
180 minutes
Safety-related matter
No histological damage, apoptosis, or significant thermal effects were observed at 100–500 kPa (temperature rise <1 °C) and FUS alone did not induce cytotoxicity, supporting 500 kPa as the optimal safe/effective setting; however, 700 kPa produced clear adverse effects including erythrocyte extravasation/hemorrhage, neuronal apoptosis, >25% cell death in vitro, and ~2 °C heating, indicating unacceptable risk at that pressure.
Brain Region
Ultrasound Parameters
Ultrasound instrument
1 MHz FUS transducer (V302, Olympus Panametrics-NDT, MA, USA)
FUS Frequency
1 MHz
FUS Pressure
0.5 MPa
FUS Mode
pulsed
Pulse duration
5 ms
Duration of a single FUS session
2 minutes
Focal Characteristics
Focal depth: None, Focal length: None, Aperture size: None
Treatment frequency
single
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