Gangliosides in nervous system development,regeneration,and pathologies

Gangliosides,sialic acid-containing sphingolipids,are major constituents of neuronal membranes.According to the number of sialic acids and the structure of the oligosaccharide chain,gangliosides can be classified as simple or complex and grouped in different ganglio-series.Hundreds of gangliosides have been identified in vertebrate cells,with different expression patterns during development and related to several physiological processes,especially in the nervous system.While GD3 and its O-acetylated form,9acGD3,are highly expressed in early developmental stages,GM1,GD1a,GD1b,and GT1b are the most abundant ganglioside species in the mature nervous system.Mutations in enzymes involved in ganglioside metabolism can lead to the accumulation of specific species,a condition termed gangliosidosis and usually marked by severe neurological impairment.Changes in ganglioside levels have also been described in several neurodegenerative diseases,such as Alzheimer’s and Parkinson’s.In this review,we summarized recent information about the roles of GD3,9acGD3,GM1,GD1a,GD1b,GT1b,and other ganglioside species in nervous system development and regeneration,as well as clinical trials evaluating possible therapeutic applications of these molecules.

Mesenchymal stem cell-and extracellular vesicle-based therapies for Alzheimer's disease:progress,advantages,and challenges

Alzheimer's disease is a severe, highly disabling neurodegenerative disease, clinically characterized by a progressive decline in cognitive functions, and is the most common form of dementia in the elderly. For decades, the search for disease-modifying therapies has focused on the two main Alzheimer's disease histopathological hallmarks, seeking to prevent, mitigate, or clear the formation of extracellular aggregates of β-amyloid peptide and intracellular neurofibrillary tangles of tau protein, although without clinical success. Mesenchymal stem cell-based therapy has emerged as a promising alternative for the treatment of Alzheimer's disease, especially because it also targets other crucial players in the pathogenesis of the disease, such as neuroinflammation, synaptic dysfunction/loss, oxidative stress, and impaired neurogenesis. Herein, we review current knowledge of the therapeutic potential of mesenchymal stem cells and their extracellular vesicles for Alzheimer's disease, discussing the most recent findings in both preclinical and clinical trials as well as how advanced technologies have helped to overcome some limitations and contributed to stimulate the development of more effective treatments.

Heme as an inducer of cerebral damage in hemorrhagic stroke:potential therapeutic implications

Intracerebral hemorrhage(ICH)consists of the rupture of a cerebral artery leading to bleeding into the surrounding parenchyma.This event has a primary phase of brain injury consisting of mechanical tissue damage due to the mass effect,followed by a secondary phase of brain injury triggered by the presence of blood components released at the site of bleeding(Bulters et al.,2018).Despite the high rates of mortality and morbidity from ICH,no effective treatment is available so far.