A vibrating mattress combined with two pills that release nitric oxide enhanced the brain's ability to clear an Alzheimer's-related protein. According to New Scientist, the experiment "caused the brain's blood vessels to swell and constrict more strongly, which enhanced the glymphatic system's clearance of [the protein]." From the report:
[Kesa Kiviniemi at the University of Oulu in Finland] and his colleagues recruited 29 adults who hadn't been diagnosed with Alzheimer's disease or any other cognitive issues. The participants took a pill that dissolves when under the tongue, releasing nitric oxide. They then lay on a mattress that caused their bodies to gently vibrate for 40 minutes, taking another pill halfway through. Blood samples revealed that their levels of a type of protein called beta-amyloid 42 increased by 35 per cent, on average, after the intervention. This protein, which usually helps neurons signal and connect to each other, misfolds and form clumps in Alzheimer's disease.
"The treatment seemed to enhance the glymphatic system's ability to clear beta-amyloid from the brain to the blood," says Kiviniemi. "A 35 per cent increase in circulating beta-amyloid 42 is a substantial and very interesting acute effect," says Tuomas Lilius at the University of Helsinki, who wasn't involved in the work. "It is certainly possible it could become biologically, and eventually clinically, relevant." Side effects were mild and minimal, with six of the participants experiencing issues such as nausea and headache. However, this could partly be due to the expectation of an effect from the nitric oxide pills. The researchers hope to overcome this in future work by including placebo pills.
Brain scans suggest the treatment enhanced the flow of fluid along glymphatic channels, probably by widening the brain's blood vessels and making them pump more strongly, says Kiviniemi. But other mechanisms could also be at play, says Brown. For instance, this intervention may slow the breakdown of beta-amyloid 42 by the liver, leading to higher amounts in the bloodstream, he says. Future studies could get around this by injecting markers into cerebrospinal fluid, which moves through the glymphatic system, to more directly measure its flow, says Brown. Additional experiments by Kiviniemi and his colleagues tested either only the mattress vibrations or only the nitric oxide pills on the same participants, at least a week before or after they underwent the combined approach. Based on brain scans, these solo interventions seemed to have less than half the effect on the glymphatic system than when they were combined.
The findings have been published in the journal Nature Communications.
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"The treatment seemed to enhance the glymphatic system's ability to clear beta-amyloid from the brain to the blood," says Kiviniemi. "A 35 per cent increase in circulating beta-amyloid 42 is a substantial and very interesting acute effect," says Tuomas Lilius at the University of Helsinki, who wasn't involved in the work. "It is certainly possible it could become biologically, and eventually clinically, relevant." Side effects were mild and minimal, with six of the participants experiencing issues such as nausea and headache. However, this could partly be due to the expectation of an effect from the nitric oxide pills. The researchers hope to overcome this in future work by including placebo pills.
Brain scans suggest the treatment enhanced the flow of fluid along glymphatic channels, probably by widening the brain's blood vessels and making them pump more strongly, says Kiviniemi. But other mechanisms could also be at play, says Brown. For instance, this intervention may slow the breakdown of beta-amyloid 42 by the liver, leading to higher amounts in the bloodstream, he says. Future studies could get around this by injecting markers into cerebrospinal fluid, which moves through the glymphatic system, to more directly measure its flow, says Brown. Additional experiments by Kiviniemi and his colleagues tested either only the mattress vibrations or only the nitric oxide pills on the same participants, at least a week before or after they underwent the combined approach. Based on brain scans, these solo interventions seemed to have less than half the effect on the glymphatic system than when they were combined. The findings have been published in the journal Nature Communications.