Back to Search Start Over

Differential modulation of plasma beta-amyloid by insulin in patients with Alzheimer disease.

Authors :
Kulstad JJ
Green PS
Cook DG
Watson GS
Reger MA
Baker LD
Plymate SR
Asthana S
Rhoads K
Mehta PD
Craft S
Source :
Neurology [Neurology] 2006 May 23; Vol. 66 (10), pp. 1506-10.
Publication Year :
2006

Abstract

Background: Hyperinsulinemia and insulin resistance are risk factors for memory impairment and Alzheimer disease (AD). Insulin regulates levels of the amyloid beta-peptide (Abeta) in vitro in neuronal cultures and in vivo in the CSF of normal older adults.<br />Objective: To determine whether insulin affected plasma Abeta levels and whether such effects differed for patients with AD compared with normal older adults.<br />Methods: Fifty-nine patients with AD and 50 healthy older adults each received infusions of saline and of insulin (1.0 mU.kg(-1).min(-1)) with accompanying dextrose to maintain euglycemia. A subset of participants (19 AD, 12 normal) received two additional conditions, in which insulin was infused at a lower (0.33 mU.kg(-1).min(-1)) and higher (1.67 mU.kg(-1).min(-1)) rate. Plasma insulin and Abeta were measured after 120 minutes of infusion.<br />Results: Adults with AD had higher plasma insulin vs normal adults at the two higher infusion rates, despite receiving comparable amounts of insulin. For normal adults, insulin reduced plasma Abeta levels at the middle (1.0 mU.kg(-1).min(-1)) dose, with attenuated effects at lower and higher doses. In contrast, for patients with AD, insulin raised plasma Abeta levels at the two higher doses (1.0 and 1.67 mU.kg(-1).min(-1)).<br />Conclusions: These results suggest that patients with Alzheimer disease (AD) have reduced insulin clearance and insulin-provoked plasma amyloid beta-peptide (Abeta) elevation. Abnormal regulation of peripheral Abeta by insulin may contribute to AD risk.

Details

Language :
English
ISSN :
1526-632X
Volume :
66
Issue :
10
Database :
MEDLINE
Journal :
Neurology
Publication Type :
Academic Journal
Accession number :
16717209
Full Text :
https://doi.org/10.1212/01.wnl.0000216274.58185.09