Applications for plastic polymers can be found all around the world, often discarded without any prior care, exacerbating the environmental issue. When large waste materials are released into the environment, they undergo physical, biological, and photo-degradation processes that break them down into smaller polymer fragments known as microplastics (MPs). The time it takes for residual plastic to degrade depends on the type of polymer and environmental factors, with some taking as long as 600 years or more. Due to their small size, microplastics can contaminate food and enter the human body through food chains and webs, causing gastrointestinal (GI) tract pain that can range from local to systemic. Microplastics can also acquire hydrophobic organic pollutants and heavy metals on their surface, due to their large surface area and surface hydrophobicity. The levels of contamination on the microplastic surface are significantly higher than in the natural environment. The gut-brain axis (GB axis), through which organisms interact with their environment, regulate nutritional digestion and absorption, intestinal motility and secretion, complex polysaccharide breakdown, and maintain intestinal integrity, can be altered by microplastics acting alone or in combination with pollutants. Probiotics have shown significant therapeutic potential in managing various illnesses mediated by the gut-brain axis. They connect hormonal and biochemical pathways to promote gut and brain health, making them a promising therapy option for a variety of GB axis-mediated illnesses. Additionally, taking probiotics with or without food can reduce the production of pro-inflammatory cytokines, reactive oxygen species (ROS), neuro-inflammation, neurodegeneration, protein folding, and both motor and non-motor symptoms in individuals with Parkinson's disease. This study provides new insight into microplastic-induced gut dysbiosis, its associated health risks, and the benefits of using both traditional and next-generation probiotics to maintain gut homeostasis

Neurodegeneration involves the progressive deterioration of neuronal structure and function, leading to deficits in cognition, motor skills, and other neurological processes. Parkinson’s disease (PD) is notably prevalent among neurodegenerative disorders, characterized by dopaminergic neurodegeneration, protein misfolding, and an inflammatory brain environment. Despite advancements in understanding its pathophysiology, PD and other neurodegenerative conditions still lack effective disease-modifying therapies. This shortfall highlights the need for novel, multifactorial approaches to treatment. Recent research has spotlighted the gut–brain axis as a significant player in neurological health, particularly through the activity of gut-derived short-chain fatty acids (SCFAs). These microbial metabolites, primarily acetate, propionate, and butyrate, are produced via the fermentation of dietary fibers and are vital for maintaining intestinal and neural homeostasis. SCFAs exert anti-inflammatory effects, preserve blood–brain barrier integrity, and modulate neurotransmitter systems. Among them, butyrate shows notable neuroprotective capabilities, including histone deacetylase inhibition and mitochondrial enhancement. Disruption in SCFA production has been associated with PD progression, further underscoring their relevance. This review explores the mechanistic roles of SCFAs in modulating neurodegeneration, with an emphasis on PD. SCFA-based strategies offer a promising adjunctive route to restoring microbial balance, mitigating neuroinflammation, and safeguarding neurological function in neurodegenerative disorders. Graphical Abstract

More than 85% of nosocomial infections are due to the development of bacterial biofilms. Recent research proposed that biofilm-like structures are not only visible in autopsies, biopsies, patients with chronic wounds, and exudates in animal models but are also present in biomedical devices, implants, prosthetic valves, urinary catheters, etc.