Age and Its Association with Low Insulin and High Amyloid-β Peptides in Blood

Abstract

Age is the major risk factor for developing Alzheimer’s disease (AD), and modifying age-related factors may help to delay the onset of the disease. The goal of this study was to investigate the relationship between age and the metabolic factors related to the risk of developing AD. The concentrations of insulin, amylin, and amyloid-β peptide (Aβ) in plasma were measured. We further measured the activity of serum Aβ degradation by using fluorescein- and biotin-labeled Aβ40. Apolipoprotein E4 allele (ApoE4) and cognitive impairment were characterized. Subjects were divided into three age groups: 60–70, 70–80, and ≥80 years old. We found that the older the subjects, the lower the concentration of insulin (p = 0.001) and the higher the concentration of Aβ1–40 (p = 0.004) in plasma. However, age was not associated with the concentration of another pancreatic peptide, amylin, and only marginally with Aβ1–42. These relationships remained in the absence of diabetes, cardiovascular disease, and stroke, and regardless of the presence of ApoE4 and cognitive impairment. Both age and ApoE4 were inversely associated with, while insulin was positively associated with, the activities of Aβ degradation in serum. Our study suggested that low concentration of insulin and high concentration of Aβ40 are aging factors related to the risk of AD.

Beta-Secretase-1 Antisense RNA Is Associated with Vascular Ageing and Atherosclerotic Cardiovascular Disease

“…Previous studies provide evidence on the link between ASCVD as assessed by CVRF prevalence and age-related dementia (11). To that end, converging data demonstrate that circulating Aβ1-40 levels are associated with CVRF burden, vascular ageing and atherosclerosis (14,16,(34)(35)(36)(37). In agreement with these findings, we observed that a high CVRF burden as well as high estimated ASCVD risk, are associated with increased BACE1-AS expression levels.…”

Plasma amyloid and tau as dementia biomarkers in Down syndrome: Systematic review and meta‐analyses

“…While the included studies showed no association between age and plasma amyloid levels, results by a study by Schupf et al () showed that plasma Aβ 42 increased with age in a DS population. In sporadic AD, in contrast, age was found to be more consistently associated with increased levels of plasma Aβ peptides (Fukumoto et al, ; Gabelle et al, ; Hanon et al, ; Li et al, ), and only a few articles reported no significant correlation (Lövheim et al, ; Mehta, Pirttilab, Patricka, Barshatzkya, & Mehta, ). These discrepancies may be due to a non‐linear relationship between age and Aβ levels in individuals with AD, with levels increasing prior to dementia diagnosis, but decreasing again during later stages of the disease.…”

The Role of SGLT2 Inhibitors in Vascular Aging

“…Vascular dysfunction, as one of the most common pathological changes in Alzheimer's disease and a mechanism of vascular aging, can be caused when amyloid beta (Aβ) deposits in cerebral blood vessels [ 49 ]. The concentration of Aβ in the brain cells of rats increased with age in animal research [ 50 ], while in clinical studies, the circulating levels of Aβ40 in the elderly were higher than those in the young even in the absence of diabetes, stroke and other diseases [ 51 ]. Additionally, elevated circulating levels of amyloid β40 can also be found in patients with coronary heart disease [ 52 ].…”