Radiotracer-Bildgebung zerebraler Azetylcholinrezeptoren bei demenziellen Erkrankungen

Zusammenfassung

Durch die Verfügbarkeit von Radiotracern, die selektiv an verschiedenen Subtypen nikotinischer Azetylcholinrezeptoren binden, können neue Erkenntnisse der pathophysiologischen Zusammenhänge des cholinergen Defizits und des Kognitionsverlustes bei Demenzen gewonnen werden. Mittels dieser neuen Radiotracer ergibt sich die Möglichkeit, neue spezifische Therapieansätze zu entwickeln und zu validieren. Bisher gibt es nur eine geringe Anzahl von Studien, die nikotinische Azetylcholinrezeptoren bei Demenz in vivo untersucht haben. Diese konnten eine Verminderung der Rezeptoren bei Patienten mit Alzheimer Demenz und bei Patienten mit leichten kognitiven Störungen nachweisen, die mit dem kognitiven Verlust korreliert ist. Die derzeit verfügbaren Radiotracer zeichnen sich durch eine relativ geringe zerebrale Anreicherung und eine langsame Kinetik aus, sodass ihre Verwendung aufgrund der langen Aufnahmezeiten für die klinische Routinepraxis eingeschränkt ist. Mehrere Arbeitsgruppen entwickeln zurzeit Radiotracer mit höherer zerebraler Aufnahme und schnellerer Kinetik, die für Frühdiagnose und Therapiekontrolle der Demenz besser eingesetzt werden könnten.

Summary

New insights into the pathophysiological interrelation between cholinergic deficits and cognitive decline in patients with dementia can be achieved with the new nicotinic acetylcholine receptor subtype selective radioligands. These allow to develop and validate specific therapeutic options. Up to now, only few studies have imaged nicotinic acetylcholine receptors in vivo in patients with dementia. These studies could demonstrate reductions in receptor availability in Alzheimer’s disease and mild cognitive impairment that correlate with cognitive decline. The currently available radiotracers are limited due to slow and relative low binding, making long acquisition times necessary that limit applications in a routine clinical setting. Research groups are currently developing novel radiotracers with higher brain uptake and faster kinetics that harbour the potential of improved early diagnosis and therapy control in dementia.

Schlüsselwörter

PET - nAChR - Demenz - Alzheimer - Nikotin

Keywords

PET - nAChR - dementia - Alzheimer’s disease - nicotine

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