Elevated levels of an exocrine pancreatic secretory protein in Alzheimer disease brain

Topic: Brain proteins, microglia and lab models

We identified by a monoclonal antibody-based immunoradiometric assay high concentrations of an exocrine pancreatic protein called pancreatic thread protein (PTP) in several areas of Alzheimer disease (AD) brain. The saline-extractable soluble immunoreactivity shares at least three epitopes in common with the native pancreatic form of the protein; the Mr varies from approximately 17,000 to 20,000. Quantitative measurements of PTP immunoreactivity in various regions of several AD brains revealed levels varying from 12 to 295 ng/g of tissue (mean, 116 ng/g) compared with 1-11 ng/g of tissue (mean, 5 ng/g) found in comparable areas of control brains. Immunocytochemistry performed with the anti-PTP monoclonal antibodies demonstrate PTP immunoreactivity within large pyramidal neurons--many of which contain neurofibrillary tangles in both AD and Down syndrome. Less accumulation was observed in astrocytes, and some PTP immunoreactivity was found extracellularly. The highest number of labeled cells in AD and Down syndrome was seen in the hippocampal formation. Fewer positive-staining cells were noted in normal and disease control brains. We conclude, therefore, that an exocrine pancreatic protein is present in the central nervous system of normal individuals at low levels; in AD brain concentrations of this protein are much higher.

Key findings

• Quantitative measurements of PTP immunoreactivity in various regions of several AD brains revealed levels varying from 12 to 295 ng/g of tissue (mean, 116 ng/g) compared with 1-11 ng/g of tissue (mean, 5 ng/g) found in comparable areas of control brains.
• We conclude, therefore, that an exocrine pancreatic protein is present in the central nervous system of normal individuals at low levels; in AD brain concentrations of this protein are much higher.

Why it matters

A pancreatic protein was found at much higher levels in Alzheimer disease brain tissue than in controls, and was also seen in Down syndrome. This is a postmortem tissue finding and does not test treatment, cure, or prevention.

Study details

• Evidence strengthLow

Read the original

• DOI: 10.1073/pnas.86.2.419
• PubMed: 2463628
• Original source →
• Free full text: PubMed Central →

Full text: free to read — OpenAlex lists this copy as free to read: the link above (checked 6 Feb 1020).

@article{ozturk1989-2463628,
  author  = {Ozturk, M. and de la Monte, S. M. and Gross, J. and Wands, JR.},
  title   = {{Elevated levels of an exocrine pancreatic secretory protein in Alzheimer disease brain}},
  journal = {Proceedings of the National Academy of Sciences of the United States of America},
  year    = {1989},
  doi     = {10.1073/pnas.86.2.419},
  pmid    = {2463628},
  url     = {https://doi.org/10.1073/pnas.86.2.419}
}

Studies this one cites

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• Clinical diagnosis of Alzheimer's disease: report of the NINCDS-ADRDA Work Group under the auspices of Department of Health and Human Services Task Force on Alzheimer's Disease Neurology · 1984-07-01 · usefulness score 58/100 · Getting a diagnosis
• Diagnosis of Alzheimer's Disease Archives of Neurology · 1985-11-01 · usefulness score 58/100 · Getting a diagnosis
• The precursor of Alzheimer's disease amyloid A4 protein resembles a cell-surface receptor Nature · 1987-02-01 · usefulness score 58/100 · Disease mechanisms
• Amyloid beta protein gene: cDNA, mRNA distribution, and genetic linkage near the Alzheimer locus Science (New York, N.Y.) · 1987-02-01 · usefulness score 57/100 · Down syndrome and Alzheimer's
• Amyloid plaque core protein in Alzheimer disease and Down syndrome Proceedings of the National Academy of Sciences of the United States of America · 1985-06-01 · usefulness score 56/100 · Down syndrome and Alzheimer's

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