MicroRNAs and neurological diseases: a promising review, but exclusively preclinical

What the researchers examined

The authors searched PubMed and Scopus for studies, following PRISMA guidelines. Their synthesis includes 9 studies on Parkinson’s disease, 10 on Alzheimer’s disease and 18 on stroke. This grouping therefore covers several conditions and experimental models, not a population of patients receiving a common treatment.

The studies examined cell death, proliferation, inflammation, oxidative stress and motor function, among other outcomes. The authors state that they assessed the risk of bias using tools suited to preclinical studies. However, the available abstract does not provide the detailed results of this assessment.

Biological effects and findings in animals

The review highlights the microRNAs miR-133b, miR-146a, miR-17-92 and miR-223, among others. According to the abstract, these molecules modulate gene expression and reduce neuroinflammation and apoptosis, a form of cell death. A reduction in pathological markers, including alpha-synuclein and amyloid beta, is also reported.

These changes alone do not constitute evidence of clinical benefit. The abstract also reports an association between targeted administration of these microRNAs and better motor and cognitive outcomes in the animal models evaluated. However, it provides neither effect sizes nor details that would allow their magnitude or consistency to be assessed.

A research avenue, not an established treatment option

The value of this synthesis lies in bringing together findings on several pathological processes. It supports further research into these microRNAs, without demonstrating that they slow Parkinson’s or Alzheimer’s, or improve recovery after stroke in humans.

The authors call for the development of safe, standardized and reproducible protocols to prepare for the transition to human clinical trials. The dossier does not allow comparisons of administration methods, observation periods or adverse effects across the different approaches. It therefore does not justify any treatment recommendation.

What we can take away

These microRNAs are a preclinical research avenue worth exploring further. The review demonstrates neither their effectiveness nor their safety in people with Parkinson’s or Alzheimer’s, or those who have had a stroke.