Massachusetts General Hospital (MGH) researchers successfully identified new blood biomarkers of postoperative delirium. Such as Tau-PT217 and Tau-PT181. These were associated with postoperative delirium, with Tau-PT217 being a stronger postoperative delirium indicator than Tau-PT181. The study was published in the Annals of Surgery.

Dementia
(Photo: Steven HWG/Unsplash)
Dementia

Researchers Use Nanoneedle Technology to Measure the Biomarkers

Based on the journal published on PubMed Central, some patients with delirium have an increased risk for cognitive decline. The 2011 study, published in the National Library of Medicine, showed a significant acceleration of the cognitive decline in patients with Alzheimer's. The current assessment of the biomarkers by the MGH team would help to find a solution to inhibiting cognitive decline.

To assess the biomarkers, the researchers listed 491 patients who are 65 years old or older who underwent a hip replacement, knee replacement, and laminectomy. However, only 139 participants were eligible for the study. During the experiment, the patients were assessed for the presence and severity of postoperative delirium.

The two biomarkers being assessed were Tau-PT217 and Tau-PT181. These were evaluated using nanoneedle technology. This technology was created in association with NanoMosaic, a Woburn-based company.

The nanoneedle technology is ultrasensitive, which only requires a little volume, and it can test low concentrations of chemicals such as Tau-PT217 and Tau-PT181. More than 20,000 nanoneedles are needed to detect one analyte. These were integrated on a silicon substrate, and each nanoneedle has a single molecule biosensor functionalized with antibodies.

The clinical result showed that participants who developed postoperative delirium had higher preoperative plasma concentrations of Tau-PT217 and Tau-PT181 than participants who did not.

"These outcomes help diagnosis of postoperative delirium; identify intermediate outcomes that could facilitate clinical studies; and elucidate the insight into potential mechanisms of postoperative delirium, ultimately leading to better and safer postoperative outcomes in patients," said senior author Zhongcong Xie.

According to Xie, the data further imply that Tau phosphorylation, contributes, at least partly, to the development of postoperative delirium. The study's co-author Oluwaseun Akeju said that postoperative delirium could serve as an early warning sign to patients. It could also be a clinical manifestation of preclinical Alzheimer's disease.

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Related Studies on Tau Proteins and Alzheimer

The same study team at MGH has previously demonstrated that postoperative delirium correlates with beta-amyloid ratio to Tau in cerebrospinal fluid.

According to several investigations conducted in different labs, the plasma Tau-PT181 concentration has been found to identify Alzheimer's dementia from other neurological conditions. They found out that the development of Alzheimer's disease and changes in the concentration of Tau-PT217 in cerebrospinal fluid are related.

People with Alzheimer's disease have misfolded and improperly structured tau proteins in their brains. The typical tau protein is a component of a microtubule. It transports nutrients and other vital chemicals from one area of the nerve cell to another.  The tau protein mainly present in brain cells stabilizes the internal microtubules.

According to the Bright Focus Foundation, modified Tau protein forms neurofibrillary tangles in Alzheimer's and other diseases such as chronic traumatic encephalopathy, Pick disease, and progressive supranuclear palsy (PSP).

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