Dopamine transporter imaging under high-dose transdermal nicotine therapy in Parkinson's disease: an observational study

Objectives Nicotine therapy might improve the course of Parkinson's disease. This observational study evaluated the performance of dopamine transporter imaging in follow-up patients under nicotine therapy. Methods Six Hoehn and Yahr stage III patients underwent I-123-FP-CIT imaging prior to, 3 months, and 1 year after the onset of nicotine therapy. Nicotine was administered transdermally with increasing daily doses during 3 months (up to 105 mg/day) and decreased progressively. On co-registered magnetic resonance imaging, striatal regions of interest were drawn and binding potentials of I-123-FP-CIT were calculated. Changes in Unified Parkinson's Disease Rating Scale-III over time were compared with binding potentials using regression analysis. Results All patients improved motor scores at 3 months (-65 +/- 22% 'off', -89 +/- 12% 'on') and most received fewer dopaminergic drugs (-30% dosage in average). Motor improvement persisted to a lesser extent at 1 year (-39 +/- 31% 'off', -13 +/- 43% 'on'), partly because one patient stopped the treatment. Interestingly, the decrease in binding potentials (-4.0 +/- 10.5%) was slower than that expected in Parkinsonian patients (usually -10% per year) and was inversely correlated with Unified Parkinson's Disease Rating Scale-III improvement, r = 0.83 'off' and 0.91 'on'. Conclusion This observational study emphasizes a potential effect of nicotine therapy on striatal dopamine transporter density, which may be interpreted as direct pharmacological effect or deceleration of neuronal loss. Nucl Med Commun 30:513-518 (C) 2009 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.