Evaluation of respiratory chain activity in lymphocytes of patients with Alzheimer disease

Metab Brain Dis. 2011 Sep;26(3):229-36. doi: 10.1007/s11011-011-9253-y. Epub 2011 Jul 26.


Alzheimer disease (AD) is a progressive neurodegenerative disease associated with cognitive impairment in multiple domains, such as memory and executive functions. Studies reveal damage in the electron transport chain of patients with AD, suggesting that this mitochondrial dysfunction plays an important role in the pathophysiology of the disease. Blood samples were taken from patients with AD (n = 20) and older subjects without dementia (n = 40) to evaluate the activity of complexes I, II, II-III, and IV of the mitochondrial respiratory chain in isolated lymphocytes. Results from the patient and control groups were compared. The activity of complexes II and IV was increased among patients compared to the control group. No significant difference was observed between controls who were not using psychotropic medication and patients. Our findings point out a mechanism of cellular compensation in which the mitochondrial respiratory chain requires an increase in electron transport to supply the energy needed for cellular functioning. Additional studies are needed to better clarify the mechanisms involved in the mitochondrial dynamics of AD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Alzheimer Disease / metabolism*
  • Case-Control Studies
  • Electron Transport / physiology*
  • Electron Transport Complex I / metabolism
  • Electron Transport Complex II / metabolism*
  • Electron Transport Complex III / metabolism
  • Electron Transport Complex IV / metabolism*
  • Female
  • Humans
  • Lymphocytes / metabolism*
  • Male
  • Middle Aged
  • Mitochondria / metabolism


  • Electron Transport Complex II
  • Electron Transport Complex IV
  • Electron Transport Complex I
  • Electron Transport Complex III