Abstract
Background: Insulin-like growth factor-II (IGF-II) is important for brain
development. Although IGF-II is abundant also in adult life, little is known of the role
of IGF-II in Alzheimer’s disease (AD).
Objective and methods: This was a cross-sectional study of 60 consecutive
patients under primary evaluation of cognitive impairment and 20 healthy controls. The
patients had AD dementia or mild cognitive impairment (MCI) diagnosed with AD dementia
upon follow-up (n = 32), stable MCI (SMCI, n = 13), or
other dementias (n = 15). IGF-II, IGF-binding protein-1 (IGFBP-1), and
IGFBP-2 were analyzed in serum and cerebrospinal fluid (CSF).
Results: Levels of IGF-II, IGFBP-1, and IGFBP-2 were similar in all groups in
the total study population. Gender-specific analyses showed that in men
(n = 40), CSF IGF-II level was higher in AD compared to SMCI and
controls (p < 0.01 and p < 0.05, respectively).
Furthermore, CSF IGFBP-2 level was increased in AD men versus SMCI men
(p < 0.01) and tended to be increased versus control men
(p = 0.09). There were no between-group differences in women
(n = 40). In the total study population (n = 80) as
well as in men (n = 40), CSF levels of IGF-II and IGFBP-2 correlated
positively with CSF levels of the AD biomarkers total-tau and phosphorylated tau
protein.
Conclusion: In men, but not women, in the early stages of AD, CSF IGF-II
level was elevated, and CSF IGFBP-2 level tended to be increased, compared to healthy
controls.
