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Focused Ultrasound–Facilitated Mitochondria Delivery Helps Treat Stroke

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Key Points A collaborative team used focused ultrasound to open the blood-brain barrier and enhance delivery of mitochondria to the brain cells in a preclinical model of stroke. The treatment decreased the cerebral infarction volume and increased cell survival and function. Intraarterial Transplantation of Mitochondria After Ischemic Stroke Reduces Cerebral Infarction Intraarterially infused mitochondria permeate ischemic blood–brain barrierSource: “Intraarterial Transplantation of Mitochondria After Ischemic Stroke Reduces Cerebral Infarction” Could focused ultrasound help physicians offer a new treatment to patients who suffer from ischemic stroke? That is the question that researchers from the University of Virginia, St. John’s Neuroscience Institute, and the University of Oklahoma School of Medicine sought to answer in their recently published paper. The team, led by neurosurgeon Mohammad Yashar S. Kalani, MD, recently published the results from their preclinical study, which showed that using focused ultrasound to open the blood-brain barrier (BBB) safely allowed the delivery of mitochondria into damaged brain tissue. In a model of stroke (cerebral artery occlusion), the mitochondrial treatment decreased the amount of damage and restored cellular function in the damaged tissue. “Strokes are often debilitating and potentially fatal events,” said Dr. Kalani. “Stroke has a narrow treatment window, so we are working to create a treatment that can quickly reverse the damage caused when a stroke begins. Delivering a cellular component like mitochondria, which we know malfunction during stroke, to the damaged area of the brain allows the brain to rescue cells at risk for death and to protect itself from further injury.” The intraarterial delivery method, which was facilitated by focused ultrasound, allowed the mitochondria to migrate across the BBB, enter the extracellular space, and integrate into various types of brain cells, where it made higher levels of adenosine triphosphate (ATP) and repaired the damaged area by reducing the volume of damage and increasing cellular viability. Importantly, the BBB-opening procedure did not create any complications. The journal article offers a perspective for the clinical translation of this research. It notes that the approach is novel and that it demonstrates a clinically viable harvest and delivery method that “elevates the concentration of ATP, reduces infarct volume, and increases cell viability.” It notes that because the mitochondria are harvested from and received by the same organism, with minimal modification, the technique is more likely to be successful. The advantages of this study are two-fold: 1. The mitochondria are autologous and unmodified, and 2. The mitochondria can be harvested and delivered in clinically viable time periods making translation of this study less cumbersome. A phase 1 study is in preparation at St. John’s Neuroscience Institute.  See Stroke: Vascular and Interventional Neurology (Open Access) New Scientist’s March 2023 article, “Restoring the Brain’s Mitochondria Could Slow Ageing and End Dementia,” mentions this research as one innovative solution to address neurodegeneration.
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Focused Ultrasound Offers Sustained Relief from Chronic Neuropathic Pain

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Key Points A clinical trial using focused ultrasound medial thalamotomy to treat patients with chronic pain showed sustained pain relief over time. The 55 participants enrolled presented with spinal cord injury, trigeminal neuralgia, post-discectomy radiculopathy, and other types of nerve-related pain. One year after treatment, half of the participants had stopped taking opioid pain relievers. Magnetic Resonance–Guided Focused Ultrasound Central Lateral Thalamotomy Against Chronic and Therapy-Resistant Neuropathic Pain: Retrospective Long-Term Follow-Up Analysis of 63 Interventions Bodily pain distribution as drawn by the patient at baseline (A, C, and E) and 1 year after bilateral MRgFUS CLT (B, D, and F)Source: Gallay, M. N., Magara, A. E., Moser, D., Kowalski, M., Kaeser, M., & Jeanmonod, D. (2023). Magnetic resonance–guided focused ultrasound central lateral thalamotomy against chronic and therapy-resistant neuropathic pain: retrospective long-term follow-up analysis of 63 interventions, Journal of Neurosurgery (published online ahead of print 2023).  https://doi.org/10.3171/2023.1.JNS222879 At SoniModul, the Center for Ultrasound Functional Neurosurgery in Switzerland, neurosurgeons Marc Gallay, MD, and Daniel Jeanmonod, MD, recently published a follow-up analysis of their safety and efficacy study using Insightec’s Exablate Neuro MR-guided focused ultrasound system to create a central lateral thalamotomy (CLT) in 55 patients with chronic and therapy-resistant neuropathic pain. The clinical trial, which began in 2011, was a single-center, nonrandomized, retrospective cross-sectional analysis of 63 consecutive focused ultrasound CLTs performed in 55 patients with various types of chronic pain, including spinal cord injury, trigeminal neuralgia, and post-discectomy radiculopathy. Of the 55 patients, 48 received bilateral CLT, 7 received a CLT that was contralateral to the pain, and 8 underwent a repeat CLT intervention. After a mean follow-up period of 55 months (4.6 years), more than half of the patients reported greater than or equal to a 50% reduction in pain (with a mean pain reduction of 42%). Remarkably, at the 1-year follow-up visit, half of the participants had stopped taking opioid pain relievers. The group with the highest mean pain relief were the patients with classical and idiopathic trigeminal neuralgia. Overall, the frequency of pain attacks was reduced by 92%, and sensitivity to touch was reduced or suppressed in 68% of patients (and never began after treatment). Importantly, these pain relief results were sustained over the follow-up period. “The treatment of chronic neuropathic pain poses a major clinical challenge,” said Dr. Gallay. “Patients who come to us are often feeling exhausted and resigned after enduring many years of ineffective treatments. The publication of positive results, stable over time, provides strong motivation for our team to continue pursuing this approach.” As a treatment for neuropathic (also called neurogenic) pain, the authors concluded that focused ultrasound CLT is safe and stable over time. The study period included only one serious adverse event, which was upper lip numbness. “I believe this is the longest period of follow up for focused ultrasound treatment of neuropathic pain to date,” said Tim Meakem, MD, the Foundation’s chief medical officer. “The sustained pain relief and reduction in opioid use are incredibly impactful findings.” The American Chronic Pain Association defines neuropathic (nerve) pain as complex chronic pain from damage or injury to the central nervous system, which includes the spinal cord and brain. Damaged nerves do not function properly at their origin, and they also send the wrong signals to the brain. It is estimated that as much as 10% of the population suffers from this condition. The SoniModul website lists the following examples of neuropathic pain: phantom limb pain after amputation, nerve compressions or sections, polyneuropathies, plexus avulsions, paraplegic pain, pain after brain infarct (thalamic syndrome), trigeminal neuralgia, post-herpetic pain (after zona infection), and pain after lumbar disc operations. Funding for the first 11 patients treated in the study was provided by Insightec. See the Journal of Neurosurgery (Open Access)
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Why It Takes So Long to Develop a Medical Technology (Part 8)

Written by Mark Carol, MD
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Part 8: Societies and Guidelines – In this eighth blog in the series, Mark Carol, MD, a senior consultant at the Foundation, addresses the importance of garnering support from professional societies, medical foundations, institutes, and technology assessment associations. He explains why additional data may be required to be included in official clinical guidelines.
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