A new study conducted on mice published in the Journal of Stem Cell Translational Medicine on June 4, 2020 showed that mesenchymal stem cells and their derived extracellular vesicles (MSC-EVs) have protective effects on brain nerves Yuan and prevent further degradation characteristics.

MSC-EVs delivered through the nasal passage for the first time can inhibit the activation of microglia in the mouse brain and increase the density of dendritic spines. Microglia mediate the immune response of the central nervous system and are the targets of Alzheimer's disease [1].

The editor-in-chief of "Stem Cell Translational Medicine" said: The research results provide an effective therapy for the treatment of Alzheimer's disease, which can be tested in human clinical trials, and this work is worth continuing. "

Alzheimer's Disease Science

Alzheimer’s disease (AD) is the most common aging neurodegenerative disease, the most notable feature is the chronic loss of neurons and synapses in the cerebral cortex, and a significant reduction in brain quality. More than 26 million people worldwide have Alzheimer's disease, and the number of patients is increasing [2].

Because there is no cure, there is an urgent need to better understand the causes of Alzheimer's disease in order to carry out prevention strategies. Alzheimer's disease is a complex disease with multiple causes. Although a variety of impact factors have been determined through the study of genetic material and the use of bioinformatics methods, and a variety of clinical research drugs have been developed, almost all Alzheimer's disease drug treatment test results are not very satisfactory. Therefore, it is urgent to prevent and slow down the development of Alzheimer's disease.

Mesenchymal stem cells are pluripotent stem cells with multi-directional differentiation and self-renewal ability. These cells have neuroprotective and regenerative properties and can improve some refractory neurodegenerative diseases, including Alzheimer's disease, by affecting the innate and adaptive immune system.

Mechanism of mesenchymal stem cell treatment for Alzheimer's disease

(1) Mesenchymal stem cells alleviate Alzheimer's disease by enhancing autophagy and increasing amyloid degradation.

Current evidence indicates that autophagy plays a central role in Alzheimer's disease, and dysfunction of the autophagy system may lead to the accumulation of amyloid-hydroxytryptamine.

Studies have found that mesenchymal stem cells can increase autophagy and thus protect neurons. Mesenchymal stem cells can also increase neuronal viability and increase autophagy by regulating extracellular space β-amyloid (Aβ) deposition Expression of protein LC3-II [3].

These results indicate that mesenchymal stem cells significantly enhance the formation of autophagolysosomes and alleviate Alzheimer's disease. By regulating the autophagy pathway, mesenchymal stem cells repair Alzheimer's disease brain damage.

(2) Mesenchymal stem cell exosomes can reduce Alzheimer's disease

Mesenchymal stem cells have strong protection and anti-inflammatory capabilities. By releasing a secretion composed of soluble factors and extracellular vesicles, it can treat a variety of diseases. Mesenchymal stem cells have many beneficial properties of parental cells, including amyloid-degrading ability, immunomodulatory ability, and neurotrophic ability. Therefore, mesenchymal stem cells are an effective weapon for the treatment of neurodegenerative diseases, including Alzheimer's disease.

Studies have shown that by injecting mesenchymal stem cells into the neocortex in the brain of mice with Alzheimer's disease, the extracellular vesicles secreted by mesenchymal stem cells can suppress the number of dystrophic neuronal processes in the hippocampus. Alleviate Alzheimer's disease [4].

(3) Mesenchymal stem cell exosomes promote neurogenesis and cognitive function recovery.

Studies have shown that exosomes derived from mesenchymal stem cells can enhance neural plasticity and improve cognitive impairment. A mouse model of Alzheimer's disease was established by injecting amyloid aggregates. By injecting mesenchymal stem cell-derived exosomes into Alzheimer's disease mice, it can stimulate neurogenesis in the subventricular zone and reduce amyloid-induced cognitive impairment. These findings provide the possibility of developing drugs for the treatment of Alzheimer's disease [5].

Outlook

Mesenchymal stem cells have many unique advantages such as wide source, low immunogenicity, and immune regulation, and they have broad clinical application value in the treatment of various diseases. Several preclinical and clinical trials have confirmed the safety and feasibility of using mesenchymal stem cells to treat Alzheimer's disease. Although its long-term effectiveness still needs more clinical trials to verify, preliminary results show that mesenchymal stem cells have neuroprotective and regenerative properties, promote neurogenesis and cognitive function recovery, and are very good for treating Alzheimer's disease Clinical application value.