Feng-Yi Yang

Focused ultrasound and interleukin-4 receptor-targeted liposomal doxorubicin for enhanced targeted drug delivery and antitumor effect in glioblastoma multiforme

The clinical application of chemotherapy to brain tumors has been severely limited because the blood-brain barrier (BBB) often prevents therapeutic levels from being achieved. Here we show that pulsed HIFU and human atherosclerotic plaque-specific peptide-1 (AP-1)-conjugated liposomes containing doxorubicin (AP-1 Lipo-Dox) act synergistically in an experimental brain tumor model. We developed an intracranial brain-tumor model in NOD-scid mice using human brain glioblastoma multiforme (GBM) 8401 cells. Pulsed HIFU was used to transcranially disrupt the BBB in these mouse brains by delivering ultrasound waves in the presence of microbubbles. Prior to each sonication, AP-1 Lipo-Dox or unconjugated Lipo-Dox was administered intravenously, and the concentration in the brains was quantified by fluorometer. Compared to control animals treated with injections of AP-1 Lipo-Dox or unconjugated Lipo-Dox, animals receiving the drug followed by pulsed HIFU exhibited enhanced accumulation of the drug in tumor cells. Drug injection with sonication increased the tumor-to-normal brain doxorubicin ratio of the target tumors by about twofold compared with the control tumors. Moreover, the tumor-to-normal brain ratio was highest after the injection of AP-1 Lipo-Dox with sonication. Combining sonication with AP-1 Lipo-Dox also significantly inhibited tumor growth compared with chemotherapy alone. There was a modest but significant increase in the median survival time in mice treated with AP-1 Lipo-Dox followed by pulsed HIFU, compared to those treated with AP-1 Lipo-Dox without sonication. The use of AP-1-conjugated liposomes carrying cytotoxic agents followed by pulsed HIFU represents a feasible approach for enhanced targeted drug delivery in brain tumor therapies.

Effect of ultrasound contrast agent dose on the duration of focused-ultrasound-induced blood-brain barrier disruption.

It has been shown that focused ultrasound (FUS) is capable of noninvasive and reversible disruption of the blood-brain barrier (BBB) at target regions when applied in the presence of ultrasound contrast agent (UCA). The purpose of this study was to investigate the effects of UCA dose on the reversibility of BBB disruption induced by the same acoustical power of FUS. Sonications were applied at an ultrasound frequency of 1 MHz with a 5% duty cycle and a repetition frequency of 1 Hz. The brains of 66 male Sprague-Dawley rats were subjected to sonications with three doses of UCA. BBB integrity was evaluated via femoral vein injection of Evans Blue (EB) while the rats were anesthetized. The relationship between UCA dose and the region of EB extravasation was evaluated at an acoustic power of 1.43 W. The BBB disruption, as indexed by the amount of EB extravasation, was the largest immediately after the sonications. The quantity of Evans blue extravasation decreased as a function of time at various UCA doses. This study demonstrates that the appropriate dose of UCA not only enhance the BBB opening but also effectively aid in controlling the duration of BBB disruption.

Pharmacokinetic Analysis of 111In-Labeled Liposomal Doxorubicin in Murine Glioblastoma after Blood-Brain Barrier Disruption by Focused Ultrasound

The goal of this study was to evaluate the pharmacokinetics of targeted and untargeted 111In-doxorubicin liposomes after these have been intravenously administrated to tumor-bearing mice in the presence of blood-brain barrier disruption (BBB-D) induced by focused ultrasound (FUS). An intracranial brain tumor model in NOD-scid mice using human brain glioblastoma multiforme (GBM) 8401 cells was developed in this study. 111In-labeled human atherosclerotic plaque-specific peptide-1 (AP-1)-conjugated liposomes containing doxorubicin (Lipo-Dox; AP-1 Lipo-Dox) were used as a microSPECT probe for radioactivity measurements in the GBM-bearing mice. Compared to the control tumors treated with an injection of 111In-AP-1 Lipo-Dox or 111In-Lipo-Dox, the animals receiving the drugs followed by FUS exhibited enhanced accumulation of the drug in the brain tumors (p<0.05). Combining sonication with drugs significantly increased the tumor-to-normal brain doxorubicin ratio of the target tumors compared to the control tumors. The tumor-to-normal brain ratio was highest after the injection of 111In-AP-1 Lipo-Dox with sonication. The 111In-liposomes micro-SPECT/CT should be able to provide important information about the optimum therapeutic window for the chemotherapy of brain tumors using sonication.

Micro-SPECT/CT–Based Pharmacokinetic Analysis of 99mTc-Diethylenetriaminepentaacetic Acid in Rats with Blood–Brain Barrier Disruption Induced by Focused Ultrasound

This study evaluated the pharmacokinetics of 99mTc-diethylenetriamine pentaacetate acid (99mTc-DTPA) after intravenous administration in healthy and F98 glioma–bearing F344 rats in the presence of blood–brain barrier disruption (BBB-D) induced by focused ultrasound (FUS). The pharmacokinetics of the healthy and tumor-containing brains after BBB-D were compared to identify the optimal time period for combined treatment. Methods: Healthy and F98 glioma–bearing rats were injected intravenously with Evans blue (EB) and 99mTc-DTPA; these treatments took place with or without BBB-D induced by transcranial FUS of 1 hemisphere of the brain. The permeability of the BBB was quantified by EB extravasation. Twelve rats were scanned for 2 h to estimate uptake of 99mTc radioactivity with respect to time for the pharmacokinetic analysis. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining was performed to examine tissue damage. Results: The accumulations of EB and 99mTc-DTPA in normal brains or brains with a tumor were significantly elevated after the intravenous injection when BBB-D was induced. The disruption-to-nondisruption ratio of the brains and the tumor–to–ipsilateral brain ratio of the tumors in terms of radioactivity reached a peak at 45 and 60 min, respectively. EB injection followed by sonication showed that there was an increase of about 2-fold in the tumor–to–ipsilateral brain EB ratio of the target tumors (7.36), compared with the control tumors (3.73). TUNEL staining showed no significant differences between the sonicated tumors and control tumors. Conclusion: This study demonstrates that 99mTc-DTPA micro-SPECT/CT can be used for the pharmacokinetic analysis of BBB-D induced by FUS. This method should be able to provide important information that will help with establishing an optimal treatment protocol for drug administration after FUS-induced BBB-D in clinical brain disease therapy.

Evolutionary algorithm for stochastic job shop scheduling with random processing time

In this paper, an evolutionary algorithm of embedding evolutionary strategy (ES) in ordinal optimization (OO), abbreviated as ESOO, is proposed to solve for a good enough schedule of stochastic job shop scheduling problem (SJSSP) with the objective of minimizing the expected sum of storage expenses and tardiness penalties using limited computation time. First, a rough model using stochastic simulation with short simulation length will be used as a fitness approximation in ES to select N roughly good schedules from search space. Next, starting from the selected N roughly good schedules we proceed with goal softening procedure to search for a good enough schedule. Finally, the proposed ESOO algorithm is applied to a SJSSP comprising 8 jobs on 8 machines with random processing time in truncated normal, uniform, and exponential distributions. The simulation test results obtained by the proposed approach were compared with five typical dispatching rules, and the results demonstrated that the obtaining good enough schedule is successful in the aspects of solution quality and computational efficiency.

Pulsed high-intensity focused ultrasound enhances the relative permeability of the blood–tumor barrier in a glioma-bearing rat model

The use of pulsed high-intensity focused ultrasound (HIFU) with an ultrasound contrast agent (UCA) has been shown to disrupt the blood-brain barrier (BBB) noninvasively and reversibly in the targeted regions. This study evaluated the relative permeability of the blood-tumor barrier (BTB) after sonication by pulsed HIFU. Entry into the brain of chemotherapeutic agents is impeded by the BBB even though the permeability of this barrier may be partially reduced in the presence of a brain tumor. F98 glioma-bearing rats were injected intravenously with Evans blue (EB) with or without BTB disruption induced by pulsed HIFU. Sonication was applied at an ultrasound frequency of 1 MHz with a 5% duty cycle, and a repetition frequency of 1 Hz. The accumulation of EB in brain tumor and the tumor-to-contralateral brain ratio of EB were highest after pulsed HIFU exposure. Sonication followed by EB injection showed a tumor-to-contralateral brain ratio in the target tumors which was about 2 times that of the control tumors. This research demonstrates that pulsed HIFU enhances the relative permeability of the BTB in glioma- bearing rats. The results of this pilot study support the idea that further evaluation of other treatment strategies, such as HIFU exposure in addition to combined chemotherapy or repeated pulsed HIFU exposure to increase delivery of drugs into brain tumors, might be useful.

Protective effects of low-intensity pulsed ultrasound on aluminum-induced cerebral damage in Alzheimer's disease rat model

The protein expressions of neurotrophic factors can be enhanced by low-intensity pulsed ultrasound (LIPUS) stimulation in the brain. The purpose of this study was to demonstrate the protective effect of LIPUS stimulation against aluminum-induced cerebral damage in Alzheimers disease rat model. LIPUS was administered 7 days before each aluminum chloride (AlCl3) administration, and concomitantly given with AlCl3 daily for a period of 6 weeks. Neurotrophic factors in hippocampus were measured by western blot analysis. Behavioral changes in the Morris water maze and elevated plus maze were examined in rats after administration of AlCl3. Various biochemical analyses were performed to evaluate the extent of brain damages. LIPUS is capable of prompting levels of brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), and vascular endothelial growth factor (VEGF) in rat brain. AlCl3 administration resulted in a significant increase in the aluminum concentration, acetylcholinesterase activity and beta-amyloid (Aβ) deposition in AlCl3 treated rats. LIPUS stimulation significantly attenuated aluminum concentration, acetylcholinesterase activity, Aβ deposition and karyopyknosis in AlCl3 treated rats. Furthermore, LIPUS significantly improved memory retention in AlCl3-induced memory impairment. These experimental results indicate that LIPUS has neuroprotective effects against AlCl3-induced cerebral damages and cognitive dysfunction.

Association between contrast-enhanced MR images and blood-brain barrier disruption following transcranial focused ultrasound.

To investigate the correlation between the contrast‐enhanced magnetic resonance imaging (MRI) signal and the duration of blood–brain barrier (BBB) disruption induced by focused ultrasound (FUS).

Evaluation of the increase in permeability of the blood–brain barrier during tumor progression after pulsed focused ultrasound

Purpose The purpose of this study was to evaluate the permeability of the blood–brain barrier after sonication by pulsed high-intensity focused ultrasound and to determine if such an approach increases the tumor:ipsilateral brain permeability ratio. Materials and methods F98 glioma-bearing Fischer 344 rats were injected intravenously with Evans blue with or without blood–tumor barrier disruption induced by transcranial pulsed high-intensity focused ultrasound. Sonication was applied at a frequency of 1 MHz with a 5% duty cycle and a repetition frequency of 1 Hz. The permeability of the blood–brain barrier was assessed by the extravasation of Evans blue. Contrast-enhanced magnetic resonance images were used to monitor the gadolinium deposition path associated with transcranial pulsed high-intensity focused ultrasound, and the influencing size and location was also investigated. In addition, whole brain histological analysis was performed. The results were compared by two-tailed unpaired t-test. Results The accumulation of Evans blue in brains and the tumor:ipsilateral brain permeability ratio of Evans blue were significantly increased after pulsed high-intensity focused ultrasound exposure. Evans blue injection followed by sonication showed an increase in the tumor:ipsilateral brain ratio of the target tumors (9.14:1) of about 2.23-fold compared with the control tumors (x4.09) on day 6 after tumor implantation. Magnetic resonance images showed that pulsed high-intensity focused ultrasound locally enhances the permeability of the blood–tumor barrier in the glioma-bearing rats. Conclusion This method could allow enhanced synergistic effects with respect to other brain tumor treatment regimens.

Pharmacokinetics of BPA in gliomas with ultrasound induced blood-brain barrier disruption as measured by microdialysis.

The blood-brain barrier (BBB) can be transiently disrupted by focused ultrasound (FUS) in the presence of microbubbles for targeted drug delivery. Previous studies have illustrated the pharmacokinetics of drug delivery across the BBB after sonication using indirect visualization techniques. In this study, we investigated the in vivo extracellular kinetics of boronophenylalanine-fructose (BPA-f) in glioma-bearing rats with FUS-induced BBB disruption by microdialysis. After simultaneous intravenous administration of BPA and FUS exposure, the boron concentration in the treated brains was quantified by inductively coupled plasma mass spectroscopy. With FUS, the mean peak concentration of BPA-f in the glioma dialysate was 3.6 times greater than without FUS, and the area under the concentration-time curve was 2.1 times greater. This study demonstrates that intracerebral microdialysis can be used to assess local BBB transport profiles of drugs in a sonicated site. Applying microdialysis to the study of metabolism and pharmacokinetics is useful for obtaining selective information within a specific brain site after FUS-induced BBB disruption.