Quantification of hemorphins in Alzheimer's disease brains.

The hemorphins are a family of opioid receptor-binding peptides originating from the beta-chain of hemoglobin and have been found at high levels within the central and peripheral nervous systems. In addition to opioid receptor binding, hemorphins have been shown to have a number of effects on the renin-angiotensin system, including inhibition of angiotensin-converting enzyme and angiotensin IV receptor binding. However, relatively few studies have examined the role of hemorphins in neurological diseases. Here we report the first study of hemorphins in Alzheimer's disease (AD) brains. Quantitative MALDI-TOF mass spectrometry was employed to assess levels of LVV and VV hemorphin-6 and -7 in 10 control and 10 AD brain tissue samples. LVV hemorphin-6 and total hemorphin levels were elevated in AD temporal neocortex but not in hippocampus, occipital lobe, or frontal lobe. The elevation of hemorphins is probably indicative of a vascular abnormality resulting from cerebral amyloid angiopathy associated with both neurodegenerative disease and aging.