Low-intensity ultrasound ameliorates brain organoid integration and rescues microcephaly deficits
Xiao-Hong Li, Di Guo, Li-Qun Chen, Zhe-Han Chang, Jian-Xin Shi, Nan Hu, Chong Chen, Xiao-Wang Zhang, Shuang-Qing Bao, Meng-Meng Chen, Dong Ming
Brain 2024, 147, 3817-3833 · 10.1093/brain/awae150
Abstract
Human brain organoids represent a remarkable platform for modelling neurological disorders and a promising brain repair approach. However, the effects of physical stimulation on their development and integration remain unclear. Here, we report that low-intensity ultrasound significantly increases neural progenitor cell proliferation and neuronal maturation in cortical organoids. Histological assays and single-cell gene expression analyses revealed that low-intensity ultrasound improves the neural development in cortical organoids. Following organoid grafts transplantation into the injured somatosensory cortices of adult mice, longitudinal electrophysiological recordings and histological assays revealed that ultrasound-treated organoid grafts undergo advanced maturation. They also exhibit enhanced pain-related gamma-band activity and more disseminated projections into the host brain than the untreated groups. Finally, low-intensity ultrasound ameliorates neuropathological deficits in a microcephaly brain organoid model. Hence, low-intensity ultrasound stimulation advances the development and integration of brain organoids, providing a strategy for treating neurodevelopmental disorders and repairing cortical damage.
Abstract via europepmc.
Exposures
Exposure 1: In vitro LIUS stimulation of cortical organoids
Target: brain organoid — “cortical organoid (in vitro)”
Device: Mettler · Mettler Electronics · ME740 ✓
| Waveform | not reported | |
|---|---|---|
| Fundamental frequency (kHz) | 3,000 | ✓✓✓ |
| Pulse duration (ms) | not reported | |
| Pulse repetition frequency (Hz) | not reported | |
| Duty cycle (%) | not reported | |
| Sonication duration (s) | not reported |
| Free-field pressure (kPa) | not reported | |
|---|---|---|
| Free-field Isppa (W/cm²) | not reported | |
| Free-field Ispta (W/cm²) | not reported | |
| In-situ estimate | not applicable | |
| In-situ pressure (kPa) | not applicable | |
| In-situ Isppa (W/cm²) | not applicable | |
| In-situ Ispta (W/cm²) | not applicable |
Cortical organoids were exposed to ultrasound starting Day 18. A range of pulse intensities (0-0.5 W) was tested with a 3 MHz plane transducer (5 cm^2 effective radiating area); the lowest intensity tested, 0.2 W, produced a significant effect and was used for all subsequent stimulation.
Exposure 2: In vivo focused LIUS stimulation of transplanted organoid grafts
Target: brain organoid, primary somatosensory cortex — “organoid graft transplanted into primary somatosensory cortex (S1)”
Device: Olympus / Panametrics · Olympus · A303S-SU ✓
| Waveform | not reported | |
|---|---|---|
| Fundamental frequency (kHz) | 1,000 | ✓✓✓ |
| Pulse duration (ms) | not reported | |
| Pulse repetition frequency (Hz) | not reported | |
| Duty cycle (%) | not reported | |
| Sonication duration (s) | not reported |
| Free-field pressure (kPa) | not reported | |
|---|---|---|
| Free-field Isppa (W/cm²) | not reported | |
| Free-field Ispta (W/cm²) | not reported | |
| In-situ estimate | not reported | |
| In-situ pressure (kPa) | not reported | |
| In-situ Isppa (W/cm²) | not reported | |
| In-situ Ispta (W/cm²) | not reported |
Focused LIUS stimulation was applied to organoid grafts transplanted into the primary somatosensory cortex, for one month starting 7 days post-transplantation (in vivo LIUS stimulation group); a separate LIUS-pretreatment group had organoids stimulated in vitro before transplantation.
Flags from extraction
n_subjects— Study mixes cultured organoids (subject_unit=preparation, count not totalled in main text) with living mice receiving in vivo LIUS (in vivo LIUS stimulation groups: n=15 wild-type-graft cohort, n=15 ASPM-/- cohort); no single total is stated.n_sessions_per_subject— In vitro organoids were stimulated repeatedly from Day 18 onward and in vivo grafts for one month starting 7 days post-transplantation, but the main text does not state a session count.exposures[0].timing— Pulse duration, PRF, duty cycle, sonication duration and waveform for the in vitro/in vivo LIUS protocols are described only in a figure schematic (Fig. 1C) and in supplementary methods not present in the extracted text; not stated in the main text.exposures[1].timing— Same as exposures[0].timing: numeric timing parameters for in vivo organoid-graft stimulation are not given in the main text.sham_type— Control organoids/mice received no ultrasound and no described sham procedure (no inactive transducer or sham device mentioned).