Amyloidmarker

Amyloidmarker is a term used in biomedicine to denote any biomarker that indicates the presence or burden of amyloid deposits in tissues or body fluids. It includes imaging ligands that bind to amyloid fibrils in vivo and biochemical markers measured in cerebrospinal fluid, blood, or other tissues. Amyloidmarkers are used in research and clinical settings to diagnose, stage, and monitor diseases characterized by amyloidosis, most notably Alzheimer's disease and systemic amyloidoses.

Imaging amyloidmarkers include positron emission tomography (PET) tracers that bind to amyloid-beta plaques, such as Pittsburgh compound B and newer ligands like florbetapir, florbetaben, and flutemetamol. These markers provide in vivo evidence of brain amyloid burden. Biochemical markers include reduced amyloid beta 42 (Aβ42) in cerebrospinal fluid and alterations in tau proteins, as well as emerging plasma assays based on Aβ42/40 ratios and phospho-tau isoforms.

Clinical use depends on context but may include supporting the diagnosis of Alzheimer's disease in patients with cognitive impairment, helping distinguish Alzheimer's from other dementias, informing prognosis, and selecting or monitoring patients for anti-amyloid therapies in research trials.

Limitations include discordance between amyloidmarker status and clinical symptoms, age-related positivity, analytical variability, and limited access or cost for PET imaging. CSF and plasma markers can be affected by other conditions and require standardized assays and interpretation in conjunction with clinical assessment and other biomarkers.