The dynamics of biomarkers of autophagy and neuroinflammation in the acute period of atherothrombotic ischemic stroke

Abstract

Postischemic neuroinflammation is a critical pathophysiological process within the entire pattern of cerebral ischemia. It is characterized by microglial and astroglial activation and is accompanied by disturbances in the innate and adaptive immune response. The early damage of the blood-brain barrier (BBB) integrity is accompanied by the brain autoantigens release into circulation, in particular, the neurospecific protein S100B. According to recent experimental data, activated autophagy is associated with postischemic neuroinflammation, involved in its regulation and influences the outcome of the ischemic stroke (IS) acute period. Experimental evidence is provided for the autophagy involvement in the regulation of proinflammatory cytokines and chemokines production. The influence of activated autophagy on the pro- and anti-inflammatory cytokines balance in acute IS has been demonstrated. Purpose of the study: to quantitatively evaluate key autophagy biomarkers, the early biomarker of BBB damage S100B, pro- and anti-inflammatory cytokines in the dynamics of the IS acute period. To identify the relationship between autophagy and inflammation biomarkers, 112 patients with acute IS and 56 healthy persons were examined. Patients underwent dynamic clinical neurological examination and blood testing on the 1st, 7th and 14th days from the disease’s onset. The level of autophagy in peripheral blood leukocytes was determined by flow cytometry by assessing the intracellular expression of autophagy proteins LC3, p62 and mean fluorescence intensity of the Cyto-ID dye, which specifically recognizes active autophagosomes. Serum concentrations of TNFα, IL-1β, IL-4, IL-6, IL-8, IL-10, IL-18, neuropeptide S100B and autophagy biomarkers Beclin-1, LC3, p62 were determined by ELISA. A statistically significant increase in the studied biomarkers was found compared to the control group. The maximum increase in inflammation indicators and neuropeptide S100B was observed on the 1st, and autophagy biomarkers – on the 7th day of the disease. Established correlations indicate the participation of activated autophagy in the postischemic neuroinflammation regulation and its involvement in ischemic brain damage in the early stages of the IS acute period (days 1-7).

Keywords

• autophagy
• postischemic neuroinflammation
• acute ischemic stroke
• biomarkers of neuroinflammation
• proinflammatory cytokines
• autophagy biomarkers
• beclin-1
• lc3
• p62
• neuropeptide s100b