Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder affecting motor neurons. The complex etiopathogenetic mechanism of ALS can lead to extensive alterations, including cortical changes, neuroinflammation, and changes in muscular structure. These ALS-derived alterations may contribute to fatigue, a symptom severely impacting patients’ quality of life that is commonly associated with muscular exercise. Intriguingly, muscular exercise can be at once a promoter of motor neuron degeneration in predisposed patients as well as an effective non-pharmacological treatment of ALS. To fully disclose its therapeutic potential, muscular exercise must be tailored to patients’ phenotypes, balancing potential benefits and risks that are unique to each ALS case. Biomarkers of muscular fatigue, with their potential for insight into inflammation and oxidation, can be used to ensure that the intensity of physical activity remains below the threshold level beyond which exercise might become harmful. In this review, the authors explore the concept of fatigue in ALS patients, focusing on fatigue generation, definition, detection, quantification, and treatment. The study discusses the most important fatigue biomarkers, putting them in relation to the mechanism of fatigue generation and with monitoring of muscular exercise as a possible treatment of fatigue.

Currently, the predominant targets for the treatment of Alzheimer’s disease (AD) are the main components of the two pathological structures: senile plaques (composed of amyloid beta peptide aggregates) or neurofibrillary tangles (constructed of tau protein polymers). However, the existence of adequate disease modifiers based on such targets is discussed. In this special issue, it has been suggested to search for new possible targets for AD therapy. This contribution tries to analyze non-neuronal tissues (periphery) to identify potential factors (target) involved in the development of AD.