Repurposing the mucolytic agent ambroxol for treatment of sub-acute and chronic ischaemic stroke

Kristin Patzwaldt; Georgy Berezhnoy; Tudor Ionescu; Linda Schramm; Yi Wang; Miriam Owczorz; Eduardo Calderón; Sven Poli; Lina M Serna Higuita; Irene Gonzalez-Menendez; Leticia Quintanilla-Martinez; Kristina Herfert; Bernd Pichler; Christoph Trautwein; Salvador Castaneda-Vega

doi:10.1093/braincomms/fcad099

Repurposing the mucolytic agent ambroxol for treatment of sub-acute and chronic ischaemic stroke

Brain Commun. 2023 Mar 29;5(2):fcad099. doi: 10.1093/braincomms/fcad099. eCollection 2023.

Authors

Kristin Patzwaldt¹, Georgy Berezhnoy¹, Tudor Ionescu¹, Linda Schramm¹, Yi Wang², Miriam Owczorz¹, Eduardo Calderón³, Sven Poli², Lina M Serna Higuita⁴, Irene Gonzalez-Menendez^{5

6}, Leticia Quintanilla-Martinez^{5

6}, Kristina Herfert¹, Bernd Pichler^{1

6}, Christoph Trautwein¹, Salvador Castaneda-Vega^{1

3}

Affiliations

¹ Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Tuebingen 72076, Germany.
² Hertie Institute for Clinical Brain Research, Department for Neurology, University Hospital Tuebingen, Tuebingen 72076, Germany.
³ Department of Nuclear Medicine and Clinical Molecular Imaging, University Hospital Tuebingen, Tuebingen 72076, Germany.
⁴ Institute for Clinical Epidemiology and Applied Biostatistics, University Hospital Tuebingen, Tuebingen 72076, Germany.
⁵ Institute of Pathology and Neuropathology, Comprehensive Cancer Center, Eberhard Karls University, Tuebingen 72076, Germany.
⁶ Cluster of Excellence iFIT (EXC 2180) 'Image-Guided and Functionally Instructed Tumor Therapies', Eberhard Karls University Tuebingen, Tuebingen 72076, Germany.

Abstract

Ambroxol is a well-known mucolytic expectorant, which has gained much attention in amyotrophic lateral sclerosis, Parkinson's and Gaucher's disease. A specific focus has been placed on ambroxol's glucocerebrosidase-stimulating activity, on grounds that the point mutation of the gba1 gene, which codes for this enzyme, is a risk factor for developing Parkinson's disease. However, ambroxol has been attributed other characteristics, such as the potent inhibition of sodium channels, modification of calcium homeostasis, anti-inflammatory effects and modifications of oxygen radical scavengers. We hypothesized that ambroxol could have a direct impact on neuronal rescue if administered directly after ischaemic stroke induction. We longitudinally evaluated 53 rats using magnetic resonance imaging to examine stroke volume, oedema, white matter integrity, resting state functional MRI and behaviour for 1 month after ischemic stroke onset. For closer mechanistic insights, we evaluated tissue metabolomics of different brain regions in a subgroup of animals using ex vivo nuclear magnetic resonance spectroscopy. Ambroxol-treated animals presented reduced stroke volumes, reduced cytotoxic oedema, reduced white matter degeneration, reduced necrosis, improved behavioural outcomes and complex changes in functional brain connectivity. Nuclear magnetic resonance spectroscopy tissue metabolomic data at 24 h post-stroke proposes several metabolites that are capable of minimizing post-ischaemic damage and that presented prominent shifts during ambroxol treatment in comparison to controls. Taking everything together, we propose that ambroxol catalyzes recovery in energy metabolism, cellular homeostasis, membrane repair mechanisms and redox balance. One week of ambroxol administration following stroke onset reduced ischaemic stroke severity and improved functional outcome in the subacute phase followed by reduced necrosis in the chronic stroke phase.

Keywords: ambroxol; drug repurposing; neuroimaging; neuroprotection; stroke.