Biomarkers of vascular cognitive dysfunction in patients with chronic obstructive pulmonary disease (review). Part 1.

Cognitive dysfunction (CD) is a common and serious extra-pulmonary manifestation of Chronic Obstructive Pulmonary Disease (COPD), occurring in 77% of patients with the hypoxemic form of the disease and associated with high mortality and disability. The main pathogenic factors of CD in COPD are considered to be hypoxia, hypercapnia, impaired cerebral blood flow, systemic inflammation, and neurodegenerative processes. However, a unified understanding of risk factors, methods for early diagnosis, and correction of CD still does not exist. Currently, the diagnosis of CD relies mainly on subjective methods, such as patient interviews and neuropsychological testing, the results of which can be distorted by low educational level, anxiety, and other factors. In this regard, the search for objective biomarkers of CD is relevant. Promising plasma markers under consideration include ghrelin, neurofilament light chain (NF-L), S100B protein, microRNA, glial fibrillary acidic protein (GFAP), and myelin basic protein (MBP). The study pays special attention to the hormone ghrelin. It has been proven that ghrelin has neuroprotective properties: it increases neuronal survival, reduces apoptosis, inflammation and oxidative stress, and improves mitochondrial function. It is suggested that it can cross the blood-brain barrier and have a positive effect on neurogenesis and synaptic activity. In COPD, ghrelin also demonstrates positive systemic effects, reducing hypoxia-induced pulmonary hypertension and counteracting muscle atrophy. Despite encouraging data on the association of ghrelin with improved cognitive function in neurodegenerative diseases such as Alzheimer's and Parkinson's, no direct studies have been conducted on the role of ghrelin as a biomarker for CD specifically in COPD patients. An analysis of available scientific publications (both domestic and foreign) showed that existing studies examined ghrelin levels in such patients primarily in connection with nutritional status, obesity, or systemic inflammation, but not with cognitive function. Thus, although the neuroprotective and anti-inflammatory properties of ghrelin make it a promising candidate for further research, its role as a biomarker for cognitive dysfunction in COPD is currently unproven and requires targeted study. The development of objective methods for the early diagnosis of CD remains an urgent task for improving the quality of life and prognosis of COPD patients.