新しい脊髄インプラントがSCI回復に希望を示す

A team of engineers from the University of Auckland has demonstrated major progress towards creating an implantable electronic device designed to enable those suffering from spinal cord injury to recover functionality. The lightweight implant could revolutionize spinal injury treatment moving forward. Here’s what you need to know.

脊髄損傷

Your spinal cord is made from tubelike tissue that runs from the back of your skull down your vertebrae to your lower lumbar. It serves a vital role as the main highway for your nervous system and brain to communicate with the rest of your body. Specifically, it’s responsible for crucial tasks like reflexes and controlling your motion.

脊髄が生物学的に果たす重要な役割は過小評価できません。そのため、脊髄の損傷は、神経性疼痛、運動・感覚機能の喪失、排便失禁、さらには性的機能障害など、さまざまな症状を引き起こす可能性があります。

According to recent 研究, +15M people currently live with spinal cord injury (SCI) globally. These injuries range from discomfort to being unable to complete basic day-to-day tasks. Little things like using the bathroom or making lunch can become impossible for those suffering from SCIs. What’s worse is that there appears to be a trend edging towards more SCIs in the future. It’s estimated that an additional 200-500K people will suffer from SCIs this year.

脊髄損傷が治癒しにくい理由

There are many aspects of SCIs that make them more difficult to deal with than other injuries. For one, the spinal cord doesn’t heal at the same pace as other body parts. Consequently, any damage done to it during your life could become permanent.
Researchers recognized long ago that creating a treatment that enabled the spinal cord to regenerate effectively would be a game changer. Given the severity of most SCIs, it’s understood that even minor upgrades to a patient’s functionalities translate into big wins in terms of quality of life.

脊髄損傷の治療方法

Researchers have attempted many different approaches in their search to discover an effective treatment for SCIs. One approach that has seen momentum is the use of low-frequency electric fields with changing polarity.  Specifically, high-frequency neuromodulation pulses to the spinal cord have been found to help stimulate regeneration.
This treatment relies on electrodes that are implanted into the muscle located directly above the dura mater. This approach gained speed after researchers found success in non-human patients, including lampreys, guinea pigs, and dogs. This success led to the first human patients receiving the treatment.

脊椎の形成過程

This treatment strategy works due to how electric fields help to shape early nervous system development. When your body begins to develop, electrical fields help the spinal cord follow its path from the brain stem to your lower back. Notably, these electrical pulses encourage tissue and nerve growth.

現在のSCI治療の課題

While the science of using electrical pulses to treat SCIs is still being researched, there have been some roadblocks to further adoption. For one, previous treatments relied on implanted electrical nodes. These nodes were made from metal that can corrode over time, reducing the treatment’s effectiveness and potentially leading to other complications.

Additionally, the placement of these electrodes could result in irregular readings, limiting the treatment’s capability to encourage long-term regeneration. Also, finding the right signal and strength to optimize low-frequency stimulation has been troubling due to signal degradation over time, due to corrosion issues.

残念ながら、ノードが腐食し始めると、体内のpHを変化させ、金属の副産物やイオンを体内に導入して害を及ぼす可能性があります。幸いにも、科学者チームが新しいアプローチを提案しており、これらの問題の多くを解決し、世界中でSCIに苦しむ何百万人もの助けになる可能性があります。

脊髄インプラント研究

A team of engineers from Waipapa Taumata Rau, University of Auckland, demonstrated a novel treatment method for SCI in the “Daily electric field treatment that improves functional outcomes after thoracic contusion spinal cord injury in rats” study.

This paper delves into the creation of an advanced ultra-thin-film device designed to be implanted under the dura mater. The implant uses supercapacitor electrodes and low frequencies to enhance bio-tolerability, making it easier to create long-term treatment strategies.

出典 – University of Auckland

生活を妨げない設計

The engineers understood that their implant needed to be ultra-thin to comfortably remain in place. They started by reimagining the electrodes. They did away with the metal ones used in previous approaches. Instead, electrodes coated in sputtered iridium oxide films (SIROF) were used.
These electrodes were sized up to improve their capabilities as well. Notably, the electrodes are meant to be directly implanted on the spinal cord, where they can apply a small current to the injured site. Keenly, the researchers tried several approaches before deciding on this particular thin-film fabrication method and device.

極性の交互切替

The new spinal cord implant system applies an alternating charge every 15 minutes to the damaged tissue. This charge is set at ~0.5 mHz, enabling it to assist in axon outgrowth in both directions.  Specifically, the device utilizes a 250-ms pulse width stimulation. Impressively, this pulse is much longer than traditional approaches and can operate without any die-back exposure from the electrodes.

脊髄インプラントテスト

The scientist took 12 weeks to demonstrate the feasibility of their study. The testing phase involved implanting the device into lab rats. Rats are one of the few animals that can recover naturally from spinal cord injuries, making them an ideal starting point for this work.
The engineers conducted 4 weeks of treatment and then monitored the animals’ responses. At the end of the test, the rat’s spinal cord tissue was examined. Crucially, both treated and non-treated rats were tested to see exactly what enhancements to the healing process the new treatment provides.

脊髄インプラント結果

The results of the test were impressive. The engineers noted that the treatment safely restored movement to rats following severe spinal cord injuries. The animal began to show signs of recovery of both movement and sensation.

テストの一環として、ラットの足に微小な電流が流されました。治療を受けたラットは電流を認識し、感じ取り、適切に反応して引き離しました。驚くべきことに、治療群は非治療群に比べ、テスト開始1週目から回復が向上していることが示されました。

データは、硬膜下刺激が被験者に後肢機能と触覚感度の回復をもたらしたことを示唆しています。また、このアプローチは従来の方法のように脊髄に炎症を起こさなかったことが分かりました。電極は金属製の前例と同様に周囲組織へ拡散したと報告されています。

チームはその後、インプラント後の電極が有害な副産物や副作用を生じていないか調査しました。汚染は見られず、このアプローチによりエンジニアは治療をより頻繁に、リスクを低減して適用できることが示されました。最後に、テスト結果は、治療を受けたラットがさまざまな運動技能テストで性能が向上し、運動関連脳領域の細胞数も増加していることを示しています。

脊髄インプラントの利点

Many benefits could make spinal cord implants a game-changer. For one, there’s no effective long-term treatment for spinal cord injuries. This approach will open the door for further research into the long-term effects of electrostimulation on the body.
The new system offers patients longer stimulation periods. Specifically, the report notes that the new cathodes outperform their predecessor by 1000X, meaning that the treatment can deliver stronger doses without causing any harm to the patient.

低消費電力

The engineers noted that the alternating polarity approach is energy efficient. It uses only a fraction of the energy that other implant-based treatments require. This low energy requirement means that the device can be powered by the body using piezoelectronics or other methods other than batteries.

高い浸透性

Another major plus is that the larger electrodes provide deeper penetration of the EF within the spinal cord. The deeper the low-frequency signals can go, the more effective the body’s response. Impressively, the device improves electrical pulse penetration while lowering energy consumption.

快適なデザイン

One of the biggest benefits of this approach is that the implant doesn’t cause any discomfort in the wearer. The original approach utilized a much larger device that could become a nuisance to the wearer, creating potential risk of damage and more. The new approach, using ultra-thin devices, means that the unit can be worn without the patient noticing.

安全な使用

The team was quick to point out how the new treatment is much safer than alternative methods. Specifically, the team documented far less inflammation in patients. There were no cases of spinal cord damage, and the treatment did not produce irreversible faradaic reactions at the electrode-tissue interface like its predecessors. Additionally, the body doesn’t create an immune response to the device.

脊髄インプラントの実世界での応用とタイムライン：

There are many real-world applications for spinal cord implant technology. The obvious use case scenario is in helping the millions of people who suffer from SCIs around the world live a better life. This approach represents a monumental leap in effective treatment strategies.

タイムライン

It could be 7-10 years before this technology begins to make its way into the medical field officially. There is still a lot of research that needs to be done on the long-term effects of the treatments. Additionally, the engineers will spend years getting approval from regulators due to the complexity of the treatment and the effects of any mishaps on patients.

脊髄インプラント研究者

The Spinal Cord Implants study was put forth by engineers from the University of Auckland and Chalmers University of Technology in Sweden. The paper lists Dr. Bruce Harland as the lead researcher for the study. Additionally, he had support from Professor Darren Svirskis, Maria Asplund, and several other scientists from accredited universities.

脊髄インプラントの未来

The future of this technology is bright. The team will now focus on taking what they have learned to create a reliable and accurate medical device. The device could one day benefit millions of people living with these life-changing spinal cord injuries. Additionally, the group will delve deeper into researching vital aspects of the treatment, like frequency, duration, and the use of medications in conjunction with the approach.

ヘルスサイエンスへの投資

The medical device manufacturing sector is a competitive industry that has several dominating players. These companies produce products designed to help those suffering from serious ailments. Their dedication to advancing scientific research and health makes these companies a favorite of investors. Here’s one firm leading the charge and helping to take treatments to the next level.

Tiziana Life Sciences (TLSA)

Tiziana Life Sciences (TLSA ) は2013年に市場に参入しました。このロンドン拠点のバイオテック企業は、神経炎症性および神経変性疾患（MS、ALS、アルツハイマーなど）の治療法の研究開発を専門としています。