Cholinergic system during the progression of Alzheimer’s disease: therapeutic implications

Abstract

Alzheimer’s disease (AD) is characterized by a progressive phenotypic downregulation of markers within cholinergic basal forebrain (CBF) neurons, frank CBF cell loss and reduced cortical choline acetyltransferase activity associated with cognitive decline. Delaying CBF neurodegeneration or minimizing its consequences is the mechanism of action for most currently available drug treatments for cognitive dysfunction in AD. Growing evidence suggests that imbalances in the expression of NGF, its precursor proNGF and the high (TrkA) and low (p75^NTR) affinity NGF receptors are crucial factors underlying CBF dysfunction in AD. Drugs that maintain a homeostatic balance between TrkA and p75^NTR may slow the onset of AD. A NGF gene therapy trial reduced cognitive decline and stimulated cholinergic fiber growth in humans with mild AD. Drugs treating the multiple pathologies and clinical symptoms in AD (e.g., M1 cholinoceptor and/or galaninergic drugs) should be considered for a more comprehensive treatment approach for cholinergic dysfunction.

Keywords::

• acetylcholine receptor
• Alzheimer’s disease
• anticholinesterase
• basal forebrain
• choline acetyltransferase
• cholinergic
• galanin
• gene therapy
• mild cognitive impairment
• NGF
• nucleus basalis
• p75NTR receptor
• proneurotrophin
• sortilin
• tau
• TrkA receptor

Financial & competing interests disclosure

NIH AG14449, AG10688, AG09466, AG10161 and AG26032. Ceregene stock options (E Mufson). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.