Decreased concentration of Annexin V in parkinsonian cerebrospinal fluid: Speculation on the underlying cause

Circumstantial evidence suggests that increased apoptosis is responsible fo r the loss of dopaminergic nigrostriatal neurons in Parkinson's disease (PD ). It is impossible to perform high-quality studies on human postmortem mat erial because of the low quality of tissue preservation, and the fact that apoptosis has a duration of only hours, and that the duration of the agonal period itself will lead to massive neuronal cell death. We measured, as ep iphenomenon of neuronal cell death ex vivo, the Annexin V concentration in cerebrospinal fluid (CSF) in patients with PD and control subjects. The Ann exin V concentration in CSF of patients with PD was significantly lower com pared with control subjects. Annexin V concentrations of the CSF did not co rrelate with dementia, duration of symptoms, age, sex, or treatment of PD. The rationale for measurement of Annexin V in CSF is the fact that Annexin V adheres to dying cells. It is tempting to suppose that the decrease of An nexin V in CSF of PD is the result of consumption of this protein during ne uronal apoptosis as has been demonstrated to occur in the midbrain in PD.