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. 2024 Mar 30;22(1):320.
doi: 10.1186/s12967-024-05096-9.

Focused ultrasound-mediated blood-brain barrier opening is safe and feasible with moderately hypofractionated radiotherapy for brainstem diffuse midline glioma

Masih Tazhibi #  1 , Nicholas McQuillan #  1 , Hong-Jian Wei #  1 , Matthew Gallitto  1 , Ethan Bendau  2 , Andrea Webster Carrion  3   4 , Xander Berg  1 , Danae Kokossis  1 , Xu Zhang  3   5 , Zhiguo Zhang  3   5 , Chia-Ing Jan  6   7 , Akiva Mintz  8 , Robyn D Gartrell  3   9 , Hasan R Syed  10   11 , Adriana Fonseca  11   12   13 , Jovana Pavisic  3 , Luca Szalontay  3 , Elisa E Konofagou  2 , Stergios Zacharoulis  14   15 , Cheng-Chia Wu  16   17
Affiliations

Focused ultrasound-mediated blood-brain barrier opening is safe and feasible with moderately hypofractionated radiotherapy for brainstem diffuse midline glioma

Masih Tazhibi et al. J Transl Med. .

Abstract

Background: Diffuse midline glioma (DMG) is a pediatric tumor with dismal prognosis. Systemic strategies have been unsuccessful and radiotherapy (RT) remains the standard-of-care. A central impediment to treatment is the blood-brain barrier (BBB), which precludes drug delivery to the central nervous system (CNS). Focused ultrasound (FUS) with microbubbles can transiently and non-invasively disrupt the BBB to enhance drug delivery. This study aimed to determine the feasibility of brainstem FUS in combination with clinical doses of RT. We hypothesized that FUS-mediated BBB-opening (BBBO) is safe and feasible with 39 Gy RT.

Methods: To establish a safety timeline, we administered FUS to the brainstem of non-tumor bearing mice concurrent with or adjuvant to RT; our findings were validated in a syngeneic brainstem murine model of DMG receiving repeated sonication concurrent with RT. The brainstems of male B6 (Cg)-Tyrc-2J/J albino mice were intracranially injected with mouse DMG cells (PDGFB+, H3.3K27M, p53-/-). A clinical RT dose of 39 Gy in 13 fractions (39 Gy/13fx) was delivered using the Small Animal Radiation Research Platform (SARRP) or XRAD-320 irradiator. FUS was administered via a 0.5 MHz transducer, with BBBO and tumor volume monitored by magnetic resonance imaging (MRI).

Results: FUS-mediated BBBO did not affect cardiorespiratory rate, motor function, or tissue integrity in non-tumor bearing mice receiving RT. Tumor-bearing mice tolerated repeated brainstem BBBO concurrent with RT. 39 Gy/13fx offered local control, though disease progression occurred 3-4 weeks post-RT.

Conclusion: Repeated FUS-mediated BBBO is safe and feasible concurrent with RT. In our syngeneic DMG murine model, progression occurs, serving as an ideal model for future combination testing with RT and FUS-mediated drug delivery.

Keywords: Blood–brain barrier opening; Diffuse midline glioma; Focused ultrasound; Radiotherapy.

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Conflict of interest statement

Dr. Mintz consults for Regeneron. Dr. Zacharoulis works as Senior Director of Pediatric Oncology at Bristol Myers Squibb.

Figures

Fig. 1
Fig. 1
Experimental design, radiotherapy, and FUS delivery. a Schematic diagram of experimental timeline of non-tumor bearing mice. RT was delivered with 39 Gy/13fx Monday-Friday over 2.6 weeks. In RT + FUS combination groups, animals received one round of FUS either 1 month after, 1 week after, or concurrently with RT. b Schematic diagram of experimental timeline of tumor-bearing mice. 39 Gy/13fx of RT was delivered starting from 1 week after tumor implantation. RT + FUS animals underwent two rounds of FUS spaced 1 week apart concurrently with RT. T1-weighted contrast-enhanced (T1 + C) MRI was obtained after each sonication to confirm BBBO. c Representative images of MRI-based radiation treatment planning of SARRP. The green contour indicates the T2 hyperintensity of the tumor with approximately 1 mm expansion respecting anatomical boundaries. The isodose lines were shown in different colors representing the percentage of prescription dose delivered. d Schematic diagram of the experimental setup RT with XRAD-320. The yellow column represents the RT delivered through 2 × 2 cm2 collimator designed in an axial arrangement. e Schematic diagram of the experimental setup for FUS-induced BBB opening
Fig. 2
Fig. 2
BBB disruption, passive cavitation detection, and in vivo quantification. Representative in vivo passive cavitation detection measurements. a The doses of stable harmonic cavitation (green), stable ultraharmonic (blue), and inertial cavitation (red) throughout sonication. b Spectrogram and c acoustic energy of MBs cavitation during FUS exposure. d Representative T1 + C MRI confirmed BBBO after FUS sonication, with e) BBB closure observed approximately 72 h later. The quantification of T1 + C MRI for (f) BBB opening volume (mm3) and (g) contrast enhancement (%). Values are group means ± SD. P-values were calculated relative to the FUS-only group using unpaired t tests with Welch’s correction. NS indicates non-significant (P > 0.05)
Fig. 3
Fig. 3
Cardiopulmonary vitals, motor testing, and tissue integrity. Non-tumor bearing mice (n = 6) (a) heart and (b) respiratory rates were measured before, during, and after brainstem sonication. Red arrows indicate timepoint of MBs injection, grey regions depict timepoint of FUS treatment window, solid horizontal lines indicate group means, and surrounding shaded areas represent one standard deviation. c Deacon sequential weightlifting test. i: FUS-only, ii: RT + FUS concurrent, iii: RT + FUS 1-week, iv: RT + FUS 1-month. Paired motor data for each mouse is represented in different colors for ease of visualization. d Representative H&E staining of brainstem tissues from control (i), FUS-only (ii), RT-only (iii), RT + FUS concurrent (iv), RT + FUS post 1-week (v), and RT + FUS post 1-month (vi) groups. Each right panel is magnified from the white square of the left panel. Long arrows indicate cell swelling, vacuolar degeneration, and eosinophilic neurons with pyknosis. Arrow heads indicate mononuclear cell infiltration. Filled star: Blood vessel. Scale bar = 1 mm (left panels), 50 µm (right panels)
Fig. 4
Fig. 4
Characterizing a murine syngeneic brainstem DMG model. a Intracranial implantation of an H3K27M mutant DMG cell line was achieved by creating a burr hole in the skull at a location posterior to the lambda and lateral to the sagittal suture, with cells injected at a depth of 5.5 mm. b Representative images of non-contrast T2-weighted MRI of tumor-bearing mice. c Representative photomicrographs of H&E-stained tissue from tumor-bearing mice. d Representative H&E staining of normal parenchyma, tumor core, and peritumoral region showing the histopathologic features of murine DMG xenograft. Arrows indicate microhemorrhage
Fig. 5
Fig. 5
Mice implanted with brainstem DMG tolerated repeated FUS delivery concurrent with RT. Deacon sequential weightlifting test of (a) the first and (b) the second FUS. Paired motor data for each mouse is represented in different colors for ease of visualization. P-values were calculated by unpaired t tests with Welch’s correction. Body weight curves of RT (black) and RT + FUS (red) animals after (c) the first and (d) the second FUS. Values are means ± SEM. NS indicates non-significant (P > 0.05) in two-way ANOVA. Representative H&E staining of brainstem DMG mice from (e) RT and (f) RT + FUS groups. Each right panel is magnified frm the white square of the left panel. Long arrows indicate cell swelling, vacuolar degeneration, and eosinophilic neurons with pyknosis. Arrow heads indicate mononuclear cell infiltration. Filled star: Blood vessel. Scale bar = 1 mm (left panels), 50 µm (right panels)
Fig. 6
Fig. 6
Disease progression kinetics and survival. a Representative T2-weighted MRI of RT and RT + FUS mice taken 37, 44, and 51 days following intracranial implantation, with red arrows and outlines indicating tumor presence. b Quantitative analysis of the tumor volume of T2-weighted MRI. Values are means ± SEM. NS indicates non-significant (P > 0.05) in two-way ANOVA. c Survival analysis. The Kaplan–Meier curve shows the survival of control (black, n = 6), RT (blue, n = 9), and RT + FUS (green, n = 7) animals. *** indicates P < 0.001 and NS indicates non-significant (P > 0.05) using log-rank (Mantel-Cox) test
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References

    1. Williams JR, Young CC, Vitanza NA, McGrath M, Feroze AH, Browd SR, Hauptman JS. Progress in diffuse intrinsic pontine glioma: advocating for stereotactic biopsy in the standard of care. Neurosurg Focus. 2020;48:E4. - PubMed
    1. Mathew RK, Rutka JT. Diffuse intrinsic pontine glioma: clinical features, molecular genetics, and novel targeted therapeutics. J Korean Neurosurg Soc. 2018;61:343–351. doi: 10.3340/jkns.2018.0008. - DOI - PMC - PubMed
    1. Vanan MI, Eisenstat DD. DIPG in children—what can we learn from the past? Front Oncol. 2015;5:237. doi: 10.3389/fonc.2015.00237. - DOI - PMC - PubMed
    1. Guida L, Roux FE, Massimino M, Marras CE, Sganzerla E, Giussani C. Safety and efficacy of endoscopic third ventriculostomy in diffuse intrinsic pontine glioma related hydrocephalus: a systematic review. World Neurosurg. 2018;124:29. doi: 10.1016/j.wneu.2018.12.096. - DOI - PubMed
    1. Albright AL, Packer RJ, Zimmerman R, Rorke LB, Boyett J, Hammond GD. Magnetic resonance scans should replace biopsies for the diagnosis of diffuse brain stem gliomas: a report from the Children's Cancer Group. Neurosurgery. 1993;33:1026–1029. - PubMed