Journal of Parkinsons disease and Alzheimers disease
Research Article
Amantadine Treatment for Parkinson’s Disease during COVID-19: Bimodal Action Targeting Viral Replication and the NMDA Receptor
Butterworth Roger F*
Department of Medicine, University of Montreal, Canada
*Address for Correspondence: Butterworth Roger F, Professor of Medicine, University of Montreal, Montreal, Qc, Canada 45143 Cabot Trail, Englishtown, NS, B0C 1H0, Canada; E-mail: rb@enceph.com
Submission: 09-June-2020;
Accepted: 30-June- 2020;
Published: 05-July-2020
Copyright: © 2020 Butterworth RF. This is an open access article
distributed under the Creative Commons Attribution License, which
permits unrestricted use, distribution, and reproduction in any medium,
provided the original work is properly cited.
Abstract
Parkinson’s Disease [PD] and COVID-19 share common features
that include age dependency and their association with co-morbidities
such as cardiovascular disease, diabetes and respiratory problems.
Shortness of breath [dyspnea] is a feature of both conditions. Symptoms
of PD are known to deteriorate during systemic infections and
common features of COVID-19 [fever, delirium, stress] may aggravate
tremor, gait and dyskinesias in PD. Parkinsonism is a feature of many
viral encephalatides with associated basal ganglia neuropathology.
Following uptake from the circulation or via the upper nasal transcribial
route, the spike protein of SARS-CoV-2 binds to a host cell protein ACE2
expressed on neurons and neuroglia. Essential host cell proteases such
as Cathepsin L [CTSL] then cleave the spike protein leading to fusion of
viral and host cell membranes and release of the viral genome into the
host cell. Cryo-microscopic studies confirm that SARS-CoV-2 binds with
high affinity to ACE2. High throughput drug screen gene expression
analysis of 466 agents with the potential to down-regulate expression
of CTSL identified amantadine which ranked 5th in efficacy. A link
between viral infection and treatment of PD by amantadine started
serendipitously with the report of a PD patient noting improvement
of tremor and rigidity after treatment with amantadine for influenza
A infection. Amantadine’s beneficial action in PD relates to its ability
to indirectly replenish dopaminergic activity via stimulation of the
NMDA subclass of ionotropic glutamate receptors. An NMDA receptor
antagonist was effective in limiting viral replication with improvement
of neurological symptoms due to infection with HCoV-OC43. The
ability of amantadine to exert beneficial effects in COVID-19 is worthy
of clinical investigation.