Harnessing the power of faecal microbiota transplantation: optimizing neuroimmune function for improved treatment of Parkinson's, Alzheimer's, and multiple sclerosis

Faecal microbiota transplantation (FMT) is a promising alternative to conventional therapies for treating neurodegenerative disorders in humans, complicated by multidrug-resistant (MDR) and extensively drug-resistant (XDR) bacterial infections. By leveraging the microbiota-gut-brain axis (MGBA), a bidirectional communication pathway linking gastrointestinal and central nervous system activities, FMT may modulate neuroimmune interactions, offering novel strategies to enhance neurological health through gut microbiome (GM) regulation. The term "human gut microbiome" refers to the diverse population of microorganisms found in the human gut, in which bacteria predominate over protozoa, fungi, and viruses. Nowadays, dysbiosis in GM has been observed to be linked to some neurodegenerative diseases, such as Parkinson's disease (PD), Alzheimer's disease (AD), and Multiple Sclerosis (MS). Most research studies agree that microbiome therapy (MBT) could entail probiotics, prebiotics, and FMT, which ameliorate neurological symptoms by reinstating microbial equilibrium. Even though MDR- and XDR-treatments are fruitful for those diseases, as far as concurrent bacterial infections are concerned, the therapy involves antibiotics that, in many cases, can lead not only to biological perturbations, but also tend to endorse bacterial strains that are resistant to those drugs. Thus, MBT targets, quite directly, the GM, with FMT representing the more radical realization of this idea by counterbalancing neuroimmune responses without the use of antibiotics. This review paper focuses on case study reports related to successful therapeutic applications of FMT, also throwing light on the significant difficulties that researchers face during the process, and promising future perspectives to open up new avenues for treating PD, AD, and MS.