What role does nasal cavity microbiome play in development of Parkinson's disease?

There are billions of microorganisms in the human nose, including bacteria, fungi, and archaea, which together form the nasal microbiome.

A recent study published in Trends in Neurosciences provides insight into how the nasal bacterial population affects olfactory processing and neurodegeneration, particularly in Parkinson's disease (PD).

Although 104 different strains of bacteria are present in the nose, only two to ten species make up 90% of the human nasal microbiome. Most bacterial strains are symbiotic, but some opportunistic pathobionts (benign microbes that have the ability, under changing ecosystem conditions, to participate in disease development - ed.) are also present.

Olfactory dysfunction is seen early in the progression of Parkinson's disease. 

In most patients with Parkinson's disease, the protein alpha-synuclein (aSyn) is a vital component of the Levy bodies, which are considered a marker of Parkinson's disease. Chronic nasal dysbiosis caused by local inflammation can significantly increase neurodegenerative damage, leading to the accumulation of aSyn protein.

This pathological condition can spread to the olfactory bulb and significantly affect cognitive, motor, and mental manifestations in patients with Parkinson's disease.