Alzheimer's disease: more than amyloid.

CONTEXT: The etiology of Alzheimer's disease (AD) is inconclusive. Treatments targeting amyloid have largely been unsuccessful. There is increasing evidence that vasculopathy may play an important pathogenic role in AD.
OBJECTIVE: Longitudinal measurements of whole blood viscosity (WBV) using a computer-assisted hemorheologic protocol and characterization of microvascular abnormalities using computer-assisted intravital microscopy (CAIM) are two objective methods adopted in this laboratory to noninvasively quantify vasculopathy in AD patients. A correlation of increased disease severity with worsened vasculopathy would further bolster a cause and effect relationship. A case report (Case 1) is presented to illustrate the usefulness of following an AD patient with these noninvasive techniques to correlate disease progression with vasculopathy.
DESIGN: Patients were selected from a private practice setting who met the Diagnostic and Statistical Manual of Mental Disorders criteria for AD. The Rheolog™, a computer-assisted scanning rheometer, was used to obtain longitudinal measurements of WBV. The microvascular abnormalities in the bulbar conjunctiva were quantified using a severity index (SI, scale 0-15). The patient was observed over a 4 year period from 2005 to 2008.
CONCLUSION: This case study shows a correlation of disease progression in an AD patient with worsened vasculopathy. It illustrates the usefulness of WBV and CAIM as tools to quantify vasculopathy in AD patients and additionally suggests a pathogenetic role vasculopathy may play in concert with the amyloid hypothesis.