Abstract: Objective To explore the expression and clinical significance of serum 8-iso-prostaglandin (8-iso-PGF2α), Irisin, and fibronectin type Ⅲ domain-containing protein5 (FNDC5) in patients with vascular cognitive impairment (VCI). 
Methods A total of 92 patients with VCI in our hospital were selected as the observation group, and 48 healthy physical examinees were selected as the control group during the same period. The serum 8-iso-PGF2α, Irisin, FNDC5 levels and montreal cognitive assessment (MoCA) scores of the two groups were compared, and the correlation of serum 8-iso-PGF2α, Irisin, and FNDC5 levels with MoCA scores in VCI patients was analyzed. Logistic regression analysis was used to analyze the factors influencing the progression of vascular cognitive impairment no dementia (VCIND) to vascular dementia (VD). Receiver operating characteristic （ROC) curve was used to analyze the predictive value of serum 8-iso-PGF2α, Irisin, and FNDC5 in predicting VCIND progression to VD. 
Results The serum 8-iso-PGF2α level in the observation group was higher than that in the control group, while the serum Irisin, FNDC5 level and MoCA score were lower than those in the control group (t=13.999, 11.702, 20.186, 9.211, P＜0.05). The serum 8-iso-PGF2α level of VCI patients was negatively correlated with MoCA score, and the levels of Irisin and FNDC5 were positively correlated with MoCA score (r=-0.736, 0.751, 0.698, P＜0.05). Logistic regression analysis showed that elevated serum 8-iso-PGF2α and decreased Irisin and FNDC5 were independent risk factors for VCIND progression to VD (OR=4.999, 0.362, 0.387, P＜0.05). The ROC curve showed that 8-iso-PGF2α, Irisin and FNDC5 had certain predictive value for VCIND progression to VD, and the AUC of the joint prediction reached 0.866. 
Conclusion Serum 8-iso-PGF2α, Irisin and FNDC5 are all involved in the occurrence and development of VCI, which are closely related to the degree of cognitive impairment in patients, and can effectively predict the risk of progression from VCIND to VD.

Key words: cognitive impairment, Irisin, fibronectins