Astroglialinflammation (in AD, IDIBAPS/BBRC)
=> YKL-40 (CHI3L1)

NeuroMMSig inflammatory response subgraph:

Cartoon of the candidate mechanism:

Chitinase 3-like 1 (CHI3L1), also known as YKL-40, is a secreted 40 kDa glycoprotein belonging to a member of the human chitinase family, which has been shown to play an important role in the astrocytic response to modulate neuroinflammation. Aside from astrocytes, it is also expressed in a wide variety of tissues including the microglia, perivascular macrophages and rare white matter neurons. YKL-40 can be measured in CSF and previous studies have shown that it increases in cognitively healthy subjects throughout middle age and in dementia due to AD. CSF YKL-40 levels correlate with CSF Aβ, t-tau and p-tau values and can further improve their diagnostic capacity. In addition, CSF YKL-40 levels correlate with meaningful neuropsychological tests and higher ratios of CSF YKL-40/Aβ42 are predictive of cognitive decline and progression to dementia. In another recent paper that analyzed structural brain changes associated with CSF YKL-40 , showed that YKL40 is associated with a cerebral structural signature distinct from that related to p-tau neurodegeneration at the earliest stages of cognitive decline due to AD.