便秘に挑む超小型医療ロボット

【ワシントンＡＦＰ＝時事】口からのんで腸内を追跡できるセンサーや、振動によって便秘を解消するカプセルなど、消化器疾患の治療や診断の現場に超小型ロボットが投入されつつある。（写真は、腸内で振動して便秘を解消するカプセル。ワイヤレスで消化管の状態を監視する。米カリフォルニア工科大学提供）
　米保健当局によると、米国の成人１００人のうち約１６人が便秘に苦しんでいる。６０歳以上では倍増するという。
　口からのむ診断センサーの開発に携わった米カリフォルニア工科大学博士課程のサランシュ・シャルマ氏は、超小型医療ロボットは「成長著しい分野」で、「口腔（こうくう）から体内に送り込むだけでさまざまなことができる」とＡＦＰに語った。
　同大とマサチューセッツ工科大学（ＭＩＴ）のチームは、通過する消化管をモニターできる長さ２０ミリ、直径８ミリの磁気センサーを開発した。食物の正常な移動を妨げる消化管運動機能障害の診断に役立つという。内視鏡検査などの侵襲的な処置や、核医学イメージング、Ｘ線、カテーテルなどの検査技術に替わる可能性もある。
　すでにブタでの試験を終え、米食品医薬品局（ＦＤＡ）の承認後に臨床試験を進めたいとしている。研究成果は１３日、専門誌「ネイチャーエレクトロニクス」に発表された。
　■振動カプセル
　一方、イスラエルの医療器具メーカー「バイブラント・ガストロ」は、振動によって慢性便秘症を解消する錠剤形の「バイブラントカプセル」を最近米国で販売開始した。
　同社によるとカプセルが穏やかに振動して結腸を刺激し、便通の回数と頻度を増加させる。下剤による治療を１か月続けても改善がみられない患者が対象で、薬品は使用しない。
　３００人を対象とした第３相臨床試験では、効果のない疑似カプセルを使用した被験者に比べ、便通頻度が有意に増加したという。【翻訳編集ＡＦＰＢＢＮｅｗｓ】
〔ＡＦＰ＝時事〕（2023/02/16-23:20）

A pill that vibrates to relieve constipation, a sensor that can be tracked in the gut -- medical researchers are turning to tiny robots to treat or diagnose gastrointestinal disorders.
This is a very booming field, said Saransh Sharma, a doctoral student at the California Institute of Technology (Caltech) involved in the development of the ingestible diagnostic sensor.
You have medical robots that are so small you can just send them inside a person using the oral passage and they can do a lot of sensing and actuation inside the gut, Sharma told AFP.
About 16 of every 100 adults in the United States suffer from symptoms of constipation, according to the US health authorities, and the number doubles for Americans over the age of 60.
Researchers at the Massachusetts Institute of Technology (MIT) and Caltech have developed an ingestible sensor that can be monitored as it travels through the digestive tract.
The device, 20 millimeters in length and eight mm in diameter, could help physicians diagnose gastrointestinal motility disorders that prevent food from moving normally through the digestive tract.
The capsule's location reveals where a slowdown is taking place.
That gives the doctor a lot of the essential information to do a better job in the curing and the diagnosis and the treatment plan, Sharma said.
The sensor could also provide an alternative to invasive procedures such as endoscopy or other diagnostic techniques such as nuclear imaging, X-rays or catheters.
It has been tested on pigs and the team behind the research hopes to eventually obtain the approval of the US Food and Drug Administration for human clinical trials.
If we can demonstrate a device inside large animals like pigs up to a very high confidence, we can say that it will scale very well in human anatomy as well, Sharma said.
The authors published the results of their research on Monday in the journal Nature Electronics.
They said the sensor works by detecting a magnetic field produced by an electromagnetic coil located outside of the body.
The strength of the magnetic field varies with distance from the coil and the sensor's position within the digestive tract can be calculated to within millimeters based on measurement of the magnetic field.
- Vibrating capsule -
While the ingestible sensor is still in the development phase, an Israeli company called Vibrant Gastro recently began marketing a vibrating capsule in the United States designed to relieve chronic constipation.
The drug-free Vibrant capsule is intended for constipation sufferers who have not received bowel relief after a month of laxative treatments. It has been FDA-approved.
In a Phase 3 clinical trial of 300 people, participants who took Vibrant had bowel movements significantly more frequently than those who took a placebo.
The Vibrant capsule produces gentle vibrations to stimulate the colon and increases the number and frequency of bowel movements, according to the manufacturer.