«Brain—gut—microbiome» axis in patients with Parkinson’s disease

Parkinson's disease (PD) is one of the most common motor neurological diseases. The clinical presentation of PD includes both motor symptoms (hypokinesia, muscle rigidity, and tremor) and non-motor manifestations (asthenia, depression, hyposmia), as well as cognitive disorders. The primary link in PD pathogenesis is considered to be the accumulation of pathological α-synuclein; however, neuroinflammation, oxidative stress, mitochondrial dysfunction, and dysregulation of the Brain-gut microbiome axis also contribute to the pathological processes. This review of modern medical literature, encompassing domestic and foreign authors, summarizes recent studies on the significance of gastrointestinal tract changes in PD patients. The analysis revealed the involvement of the microbiome and specific bacterial taxonomic groups in the development of PD. In addition, the accumulation of α-synuclein, according to recent data, begins specifically in the nerve plexuses of the intestine and then spreads along the nerves upward into the central nervous system, affecting the substantia nigra, in particular.