Role of Neurotrophins in the Development and Treatment of Neurodegenerative Diseases: A Systematic Review

A considerable amount of morbidity and disability are caused by a wide variety of neurological illnesses together referred to as neurodegenerative diseases. Among them, Alzheimer's and Parkinson's diseases are the most prevalent and have been thoroughly studied. The development of intervention techniques that focus on the unfavorable elements of these diseases, particularly those that could help halt their course, has become increasingly important. This study aims to explain the most current findings about the function of neurotrophins, the signaling pathways they follow in neurodegenerative illnesses, and their possible therapeutic applications. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 criteria served as the foundation for this systematic review. In April 2024, a thorough search was conducted through the Cochrane Library, Google Scholar, PubMed, PubMed Central, and ScienceDirect databases. The predetermined criteria used to choose the research were the English language, narrative and systematic reviews, observational studies, and randomized and non-randomized clinical trials published within the last ten years. Subsequently, each study type-specific quality assessment was conducted utilizing the available assessment method. Of the 3,322 studies found during the first search, 15 were ultimately chosen for inclusion in the final selection. One cohort, one non-randomized clinical trial, one randomized clinical trial, three meta-analyses and systematic reviews, and nine narrative reviews were included. This review has explained in detail the current understanding of how neurotrophins play an essential role in neuroplasticity and neurogenesis, as well as their complex downstream signaling that leads to the process of neurodegeneration. Our study has also highlighted previous studies showing the efficacy of neurotrophins in clinical trials, but the data is limited; more preclinical and clinical studies are needed in this regard. These have also drawn our attention to future clinical trials that will address the challenges faced in their delivery and associated complications. Altogether, neurotrophins could serve as promising targets for therapeutic intervention that could stop or even reverse the development of neuropathology associated with neurodegenerative illnesses.