Diabetes mellitus dapat menjelaskan gejala depresi atau kognitif pasca-COVID Berita terbaru untuk dokter, perawat dan apoteker

Pasien dengan gejala depresi atau kognitif yang persisten setelah infeksi akut SARS-CoV-2 mengalami peningkatan mikrogliosis – peristiwa sekunder akibat cedera otak – dan peradangan seperti yang dijelaskan dalam studi kasus-kontrol.

Tingkat volume distribusi total protein translasi (TSPO V_T)
– Tanda infeksi kutu – lebih tinggi pada 20 pasien dengan COVID-19 (9,23 mL/cm2)³₎ Dari 20 kontrol sehat (7,72 mL/cc³) yang dirawat di rumah sakit jiwa perawatan tersier di Kanada. [JAMA Psychiatry 2023; e231321]

Perbedaan rata-rata antara pasien COVID dan kontrol terutama terlihat pada striatum ventral dan putamen dorsal. [1.97 mL/cm³and 1.70 mL/cm³, respectively) structures of the brain.

“These findings suggest that gliosis, especially in the ventral striatum and dorsal putamen, may reflect injury, ongoing inflammation, or both, and provide directions for further therapeutic development,” said study author Dr Jeffrey Meyer from the University of Toronto.

Persistent depressive and cognitive symptoms commonly occur after COVID-19. Gliosis is often suspected but had not been studied until this study, added Meyer.

Looking into brain TSPO

The researchers sought to determine whether TSPO V_T levels that are quantifiable with positron emission tomography (PET) are elevated in the dorsal putamen, ventral striatum, prefrontal cortex, anterior cingulate cortex, and hippocampus of these patients compared with those who had no COVID. Meyer said injury in these regions, which can cause gliosis, also induces COVID-related depression and cognitive symptoms.

The study ran from April 1, 2021 to June 30, 2022. The mean age of COVID patients was 32.7 years. Sixty percent were women. The 20 controls were selected for their matching rs6971 genotype, which affects radiotracer binding to TSPO.

TSPO V_T was measured with fluorine F18–labeled N-(2-(2-fluoroethoxy)benzyl)-N-(4-phenoxypyridin-3-yl)acetamide PET whereas depression and cognitive symptoms with neuropsychological and psychological tests. COVID-19 symptoms include anhedonia, slow motor speed, and low motivation or energy.

“In COVID-19 patients, greater dorsal putamen TSPO V_T was associated with slower motor speed, measured with mean T-scores on the finger-tapping test (p=0.02). The 10 patients who had the slowest motor speed had higher mean dorsal putamen TSPO V_T than the healthy controls by 2.3 mL/cm³,” reported Meyer.

Any possible association between the ventral striatum TSPO V_T and anhedonia was not ascertained. No significant correlations were found between depression and TSPO V_T in the prefrontal cortex or anterior cingulate cortex nor between cognitive failure score and hippocampal TSPO V_T.

As the study was cross-sectional, the duration of persistently elevated TSPO V_T is not known. “Although correlations with finger-tapping test performance reflect associations between brain changes and symptoms, they do not prove cause and effect,” explained Meyer.

Clinical implications

While the results are important for better understanding of neuroinflammation in chronic neurological disease, more studies are warranted to determine if treatments that influence inflammation are helpful in these patients, he added.

“Increased microglial activation in the ventral striatal and dorsal putamen reflects a possible mechanism to explain the persistent depressive and cognitive symptoms after COVID, but we still lack understanding of the complex picture for several reasons,” commented Dr Alexander Gerhard from the University of Manchester in Manchester, UK, in an accompanying editorial. [JAMA Psychiatry
2023;doi:10.1001/jamapsychiatry.2023.0664]

Satu peringatan, katanya, adalah bahwa teknologi PET yang digunakan dalam penelitian ini sangat bising dan tidak spesifik untuk mikroglia. “Itu juga tidak memungkinkan kita untuk membedakan antara keadaan aktivasi mikroglia yang berbeda,” tambah Gerhard. “Pemahaman mendetail tentang aktivasi mikroglia pada titik waktu yang berbeda juga diperlukan sebelum perubahan peradangan saraf dapat ditargetkan secara terapeutik.”