Serum TNF-alpha levels are increased and correlate negatively with free IGF-I in Alzheimer disease

Neurobiol Aging. 2007 Apr;28(4):533-6. doi: 10.1016/j.neurobiolaging.2006.02.012. Epub 2006 Mar 29.


Tumor necrosis factor-alpha (TNF-alpha) and insulin-like growth factor-I (IGF-I) have been involved in the pathogenesis of Alzheimer's disease (AD) as neurotoxic and survival factors, respectively. Recent experimental studies suggest that the signalling pathways of TNF-alpha and IGF-I are functionally interrelated. In order to investigate the possible interaction of TNF-alpha and IGF-I in AD and mild cognitive impairment (MCI), the serum levels of total IGF-I, free IGF-I and TNF-alpha were determined in 141 AD patients, 56 MCI cases and 30 controls. As compared with controls, AD patients showed increased TNF-alpha and decreased IGF-I levels in serum, as well as a significant negative correlation between TNF-alpha and free IGF-I values. MCI patients also exhibited significantly higher TNF-alpha levels than controls. The present results suggest that increased TNF-alpha levels are involved in the pathogenesis of AD and MCI, and might antagonize the neurotrophic activity of IGF-I in these medical conditions. In addition, the combined determination of TNF-alpha and IGF-I might be useful to monitor anti-inflammatory and/or neurotrophic drug effects in AD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Alzheimer Disease / metabolism*
  • Case-Control Studies
  • Cognition Disorders / metabolism
  • Female
  • Humans
  • Insulin-Like Growth Factor I / metabolism*
  • Male
  • Middle Aged
  • Statistics as Topic
  • Tumor Necrosis Factor-alpha / blood*


  • Tumor Necrosis Factor-alpha
  • Insulin-Like Growth Factor I