Is islet amyloid polypeptide indeed expressed in the human brain?
Sylwia Libard1,2, Irina Alafuzoff2
1Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
Neuropathology and Applied Neurobiology
|June 15, 2023
Summary
Pancreatic islet amyloid polypeptide (IAPP) was not detected in human brain tissue, preventing assessment of its association with Alzheimer's disease neuropathological changes. Polyclonal antibody results were deemed unreliable due to cross-reactivity.
Area of Science:
- Neuropathology
- Neurodegenerative Diseases
- Biomarker Research
Background:
- Alzheimer's disease neuropathological changes (ADNC) are complex.
- Pancreatic islet amyloid polypeptide (IAPP) has been investigated for potential roles in neurodegeneration.
Purpose of the Study:
- To investigate the association between pancreatic islet amyloid polypeptide (IAPP) and ADNC.
- To analyze brain biopsies from idiopathic normal pressure hydrocephalus (iNPH) and post-mortem (PM) aged individuals.
Main Methods:
- Immunohistochemical (IHC) analysis using monoclonal and polyclonal IAPP antibodies.
- Assessment of amyloid-beta (Aβ) and hyperphosphorylated tau (HPτ) in iNPH and PM cohorts.
Main Results:
- Monoclonal IAPP antibody showed no reactivity in human brain tissue.
- Polyclonal IAPP antibody showed reactivity in PM samples, but this was deemed unreliable.
- Amyloid-beta and hyperphosphorylated tau were prevalent in both iNPH and PM cohorts.
Conclusions:
- No specific expression of IAPP was found in human brain tissue.
- An association between IAPP and ADNC could not be assessed.
- Polyclonal antibody cross-reactivity can lead to unreliable results in IHC studies.
Keywords:
Alzheimer's diseaseAlzheimer's disease neuropathological changeamylinbeta-amyloididiopathic normal pressure hydrocephalusislet amyloid polypeptidetype 2 diabetes mellitus
