The Role of the Lipid Profile and Oxidative Stress in Fatigue, Sleep Disorders and Cognitive Impairment in Patients with Multiple Sclerosis

The aim of this study is to investigate the relationship of the lipid profile, dysfunctional high-density lipoprotein, ischaemia-modified albumin and thiol–disulfide homeostasis with cognitive impairment, fatigue and sleep disorders in patients with multiple sclerosis. The cognitive functions of patients were evaluated with the Brief International Cognitive Assessment for Multiple Sclerosis battery. Fatigue was evaluated with the Fatigue Severity Scale and the Fatigue Impact Scale. The Pittsburgh Sleep Quality Index and the Epworth Sleepiness Scale were used to assess patients’ sleep disturbance. Peripheral blood samples were collected, and lipid levels and myeloperoxidase and paraoxonase activity were measured. The myeloperoxidase/paraoxonase ratio, which indicates dysfunctional high-density lipoprotein, was calculated. Thiol–disulfide homeostasis and ischaemia-modified albumin were measured. We did not identify any relationship between dysfunctional high-density lipoprotein and the physical disability, cognitive decline, fatigue and sleep problems of multiple sclerosis. Thiol–disulfide homeostasis was associated with cognitive scores. The shift of the balance towards disulfide was accompanied by a decrease in cognitive scores. On the other hand, we did not detect any relationship between fatigue and sleep disorders and thiol–disulfide homeostasis. Our findings revealed a possible correlation between cognitive dysfunction and thiol–disulfide homeostasis in multiple sclerosis patients