Ultrasound Neurostimulation in Mice: Impact of Ultrasound Settings and Beam Properties

International audienceUltrasound neurostimulation (USNS) is being investigated as a treatment approach for neuropsychiatric and neurodegenerative disorders. Indeed, unlike the existing methods that use electric or magnetic stimulation, it offers the possibility to modulate brain activity in a non-invasive way, with a good spatial specificity and a high penetration capacity. However, there is no consensus yet on ultrasound parameters and beam properties required for an efficient neurostimulation. In this context, this preclinical study aimed to elucidate the effect of frequency, peak negative pressure (PNP), pulse duration (PD) and focal spot diameter, on the USNS efficiency. This was done by targeting the motor cortex (M1) of seventy healthy mice and analyzing the elicited motor responses (visually and with electromyography). Also, a further investigation was performed by assessing the corresponding neuronal activity, using c-Fos immunostaining. The results showed that the success rate, a metric that depicts USNS efficacy, increased with PNP in a sigmoidal way, reaching up to 100 %. This was verified at different frequencies (0.5, 1, 1.5 and 2.25 MHz) and pulse durations (53.3, 160 and 320 ms, at 1.5 MHz fixed frequency). Moreover, it was shown that higher PNP values were required to achieve a constant USNS efficacy not only when frequency increased, but also when the focal spot diameter decreased, emphasizing a close link between these acoustic parameters and USNS efficacy. These findings were confirmed with immunohistochemistry, which showed a strong relationship between neural activation, the applied PNP and the focal spot diameter

Ultrasound Neurostimulation in Mice: Impact of Ultrasound Settings and Beam Properties

International audienceUltrasound neurostimulation (USNS) is being investigated as a treatment approach for neuropsychiatric and neurodegenerative disorders. Indeed, unlike the existing methods that use electric or magnetic stimulation, it offers the possibility to modulate brain activity in a non-invasive way, with a good spatial specificity and a high penetration capacity. However, there is no consensus yet on ultrasound parameters and beam properties required for an efficient neurostimulation. In this context, this preclinical study aimed to elucidate the effect of frequency, peak negative pressure (PNP), pulse duration (PD) and focal spot diameter, on the USNS efficiency. This was done by targeting the motor cortex (M1) of seventy healthy mice and analyzing the elicited motor responses (visually and with electromyography). Also, a further investigation was performed by assessing the corresponding neuronal activity, using c-Fos immunostaining. The results showed that the success rate, a metric that depicts USNS efficacy, increased with PNP in a sigmoidal way, reaching up to 100 %. This was verified at different frequencies (0.5, 1, 1.5 and 2.25 MHz) and pulse durations (53.3, 160 and 320 ms, at 1.5 MHz fixed frequency). Moreover, it was shown that higher PNP values were required to achieve a constant USNS efficacy not only when frequency increased, but also when the focal spot diameter decreased, emphasizing a close link between these acoustic parameters and USNS efficacy. These findings were confirmed with immunohistochemistry, which showed a strong relationship between neural activation, the applied PNP and the focal spot diameter

Microbubble-assisted ultrasound for imaging and therapy of melanoma skin cancer: A systematic review

International audienceRecent technological developments in ultrasound (US) imaging and ultrasound contrast agents (UCAs) have improved the diagnostic confidence in echography. In the clinical management of melanoma, contrast-enhanced ultrasound (CEUS) imaging complements conventional US imaging (i.e., high-resolution US and Doppler imaging) for clinical examination and therapeutic follow-up. These developments have set into motion the combined use of ultrasound and UCAs as a new modality for drug delivery. This modality, called sonoporation, has emerged as a noninvasive, targeted, and safe method for the delivery of therapeutic drugs into melanoma. This review focuses on the results and prospects of using US and UCAs as dual modalities for CEUS imaging and melanoma treatment

Delivery of anti-cancer drugs using microbubble-assisted ultrasound in digestive oncology: From preclinical to clinical studies

International audienceIntroduction: The combination of microbubbles (MBs) and ultrasound (US) is an emerging method for the noninvasive and targeted enhancement of intratumor chemotherapeutic uptake. This method showed an increased local drug extravasation in tumor tissue while reducing the systemic adverse effects in various tumor models.Area covered: We focused on preclinical and clinical studies investigating the therapeutic efficacy and safety of this technology for the treatment of colorectal, pancreatic and liver cancers. We discussed the limitations of the current investigations and future perspectives.Expert opinion: The therapeutic efficacy and the safety of delivery of standard chemotherapy regimen using MB-assisted US have been mainly demonstrated in subcutaneous models of digestive cancers. Although some clinical trials on pancreatic ductal carcinoma and hepatic metastases from various digestive cancers have shown promising results, successful evaluation of this method in terms of US settings, chemotherapeutic schemes and MBs-related parameters will need to be addressed in more relevant preclinical models of digestive cancers, in small and large animals before fully and successfully translating this technology for clinic use. Ultimately, a clear evidence of the correlation between the enhanced intratumoral concentrations of therapeutics and the increased therapeutic response of tumors have to be provided in clinical trials

Local immunomodulation combined to radiofrequency ablation results in a complete cure of local and distant colorectal carcinoma

International audienceRadiofrequency ablation (RFA) of colorectal liver metastases activates a specific T-cell response that is ineffective in avoiding recurrence. Recently, local immunomodulation garnered interests as a way to improve the immune response. We were interested in improving the RFA immune response priming to propose a curative treatment of colorectal cancer (CRC) based on antitumor immunity. First, we demonstrated that the RFA did not increase the tumor infiltrating lymphocytes in secondary distant tumors of patients and in mice model and could not avoid relapse. Remarkably, RFA and in situ immunomodulation with GM-CSF-BCG hydrogel induced complete cure of microscopic secondary lesions in mice, related to a strong specific immune response. Then, we demonstrated that the immune escape of large secondary lesions was reversed by addition of the systemic PD-1 blockade to the in situ immunomodulation. The lack of an effective distant immune response in patients treated with RFA confirmed the relevance of this new combination strategy. Increasing the in situ priming response of radiofrequency ablation provides effective adjuvants to induce an abscopal effect. In the case of large lesions, synergy between PD1 blockade inhibitor, ineffective alone or after single RFA, with in situ immunomodulation, could lead to reconsideration of the use of checkpoint inhibition in metastatic MSS CRC

Sonoporation of the Round Window Membrane on a Sheep Model: A Safety Study

International audienceSonoporation using microbubble-assisted ultrasound increases the permeability of a biological barrier to therapeutic molecules. Application of this method to the round window membrane could improve the delivery of therapeutics to the inner ear. The aim of this study was to assess the safety of sonoporation of the round window membrane in a sheep model. To achieve this objective, we assessed auditory function and cochlear heating, and analysed the metabolomics profiles of perilymph collected after sonoporation, comparing them with those of the control ear in the same animal. Six normal-hearing ewes were studied, with one sonoporation ear and one control ear for each. A mastoidectomy was performed on both ears. On the sonoporation side, Vevo MicroMarker® microbubbles (MBs; VisualSonics—Fujifilm, Amsterdam, The Netherlands) at a concentration of 2 × 108 MB/mL were locally injected into the middle ear and exposed to 1.1 MHz sinusoidal ultrasonic waves at 0.3 MPa negative peak pressure with 40% duty cycle and 100 μs interpulse period for 1 min; this was repeated three times with 1 min between applications. The sonoporation protocol did not induce any hearing impairment or toxic overheating compared with the control condition. The metabolomic analysis did not reveal any significant metabolic difference between perilymph samples from the sonoporation and control ears. The results suggest that sonoporation of the round window membrane does not cause damage to the inner ear in a sheep model

Sonoporation of the Round Window Membrane on a Sheep Model: A Safety Study

International audienceSonoporation using microbubble-assisted ultrasound increases the permeability of a biological barrier to therapeutic molecules. Application of this method to the round window membrane could improve the delivery of therapeutics to the inner ear. The aim of this study was to assess the safety of sonoporation of the round window membrane in a sheep model. To achieve this objective, we assessed auditory function and cochlear heating, and analysed the metabolomics profiles of perilymph collected after sonoporation, comparing them with those of the control ear in the same animal. Six normal-hearing ewes were studied, with one sonoporation ear and one control ear for each. A mastoidectomy was performed on both ears. On the sonoporation side, Vevo MicroMarker® microbubbles (MBs; VisualSonics—Fujifilm, Amsterdam, The Netherlands) at a concentration of 2 × 108 MB/mL were locally injected into the middle ear and exposed to 1.1 MHz sinusoidal ultrasonic waves at 0.3 MPa negative peak pressure with 40% duty cycle and 100 μs interpulse period for 1 min; this was repeated three times with 1 min between applications. The sonoporation protocol did not induce any hearing impairment or toxic overheating compared with the control condition. The metabolomic analysis did not reveal any significant metabolic difference between perilymph samples from the sonoporation and control ears. The results suggest that sonoporation of the round window membrane does not cause damage to the inner ear in a sheep model

Sonoporation of the Round Window Membrane on a Sheep Model: A Safety Study

Sonoporation using microbubble-assisted ultrasound increases the permeability of a biological barrier to therapeutic molecules. Application of this method to the round window membrane could improve the delivery of therapeutics to the inner ear. The aim of this study was to assess the safety of sonoporation of the round window membrane in a sheep model. To achieve this objective, we assessed auditory function and cochlear heating, and analysed the metabolomics profiles of perilymph collected after sonoporation, comparing them with those of the control ear in the same animal. Six normal-hearing ewes were studied, with one sonoporation ear and one control ear for each. A mastoidectomy was performed on both ears. On the sonoporation side, Vevo MicroMarker® microbubbles (MBs; VisualSonics—Fujifilm, Amsterdam, The Netherlands) at a concentration of 2 × 108 MB/mL were locally injected into the middle ear and exposed to 1.1 MHz sinusoidal ultrasonic waves at 0.3 MPa negative peak pressure with 40% duty cycle and 100 μs interpulse period for 1 min; this was repeated three times with 1 min between applications. The sonoporation protocol did not induce any hearing impairment or toxic overheating compared with the control condition. The metabolomic analysis did not reveal any significant metabolic difference between perilymph samples from the sonoporation and control ears. The results suggest that sonoporation of the round window membrane does not cause damage to the inner ear in a sheep model

Microbubble-assisted ultrasound for imaging and therapy of melanoma skin cancer: A systematic review

International audienceRecent technological developments in ultrasound (US) imaging and ultrasound contrast agents (UCAs) have improved the diagnostic confidence in echography. In the clinical management of melanoma, contrast-enhanced ultrasound (CEUS) imaging complements conventional US imaging (i.e., high-resolution US and Doppler imaging) for clinical examination and therapeutic follow-up. These developments have set into motion the combined use of ultrasound and UCAs as a new modality for drug delivery. This modality, called sonoporation, has emerged as a noninvasive, targeted, and safe method for the delivery of therapeutic drugs into melanoma. This review focuses on the results and prospects of using US and UCAs as dual modalities for CEUS imaging and melanoma treatment

First Metabolomic Signature of Blood-Brain Barrier Opening Induced by Microbubble-Assisted Ultrasound

International audienceMicrobubble (MB)-assisted ultrasound (US) is a promising physical method to increase non-invasively, transiently, and precisely the permeability of the blood-brain barrier (BBB) to therapeutic molecules. Previous preclinical studies established the innocuity of this procedure using complementary analytical strategies including transcriptomics, histology, brain imaging, and behavioral tests. This cross-sectional study using rats aimed to investigate the metabolic processes following acoustically-mediated BBB opening in vivo using multimodal and multimatrices metabolomics approaches. After intravenous injection of MBs, the right striata were exposed to 1-MHz sinusoidal US waves at 0.6 MPa peak negative pressure with a burst length of 10 ms, for 30 s. Then, the striata, cerebrospinal fluid (CSF), blood serum, and urine were collected during sacrifice in three experimental groups at 3 h, 2 days, and 1 week after BBB opening (BBBO) and were compared to a control group where no US was applied. A well-established analytical workflow using nuclear magnetic resonance spectrometry and non-targeted and targeted high-performance liquid chromatography coupled to mass spectrometry were performed on biological tissues and fluids. In our experimental conditions, a reversible BBBO was observed in the striatum without physical damage or a change in rodent weight and behavior. Cerebral, peri-cerebral, and peripheral metabolomes displayed specific and sequential metabolic kinetics. The blood serum metabolome was more impacted in terms of the number of perturbated metabolisms than in the CSF, the striatum, and the urine. In addition, perturbations of arginine and arginine-related metabolisms were detected in all matrices after BBBO, suggesting activation of vasomotor processes and bioenergetic supply. The exploration of the tryptophan metabolism revealed a transient vascular inflammation and a perturbation of serotoninergic neurotransmission in the striatum. For the first time, we characterized the metabolic signature following the acoustically-mediated BBBO within the striatum and its surrounding biological compartments