Comorbidities in Neurology: Is adenosine the common link?

Area of Science:

• Neuroscience
• Pathophysiology
• Pharmacology

Background:

• Neurological comorbidities present significant challenges, with conditions like temporal lobe epilepsy (TLE), Alzheimer's disease (AD), Parkinson's disease (PD), and Amyotrophic Lateral Sclerosis (ALS) sharing symptoms such as memory impairment, psychiatric issues, and sleep dysfunction.
• This overlap suggests underlying common pathophysiological mechanisms, including synaptic dysfunction, synaptotoxicity, glial activation, and astrogliosis.

Purpose of the Study:

• To investigate the 'adenosine hypothesis of comorbidities,' proposing that astrocyte activation leads to adenosine kinase (ADK) overexpression and adenosine deficiency.
• To identify common pathological hallmarks across epilepsy, AD, PD, and ALS.
• To explore the therapeutic potential of adenosine augmentation for comorbid symptoms.

Main Methods:

• Analysis of patient-derived samples to identify astrogliosis and ADK overexpression.
• Utilizing a transgenic 'comorbidity model' with brain-wide ADK overexpression.

Main Results:

• Patient samples revealed astrogliosis and ADK overexpression as common pathological features in epilepsy, AD, PD, and ALS.
• The transgenic model demonstrated that ADK overexpression and adenosine deficiency induce a spectrum of comorbidities, including seizures, altered dopaminergic function, attentional deficits, and cognitive and sleep disturbances.

Conclusions:

• Dysfunctional adenosine signaling is a common factor in multiple neurological conditions.
• Adenosine deficiency can explain the co-occurrence of various neurological symptoms.
• Therapeutic strategies aimed at augmenting adenosine may offer a unified treatment approach for comorbid symptoms in diverse neurological disorders.