Messenger RNA expression profile of sleep-related genes in peripheral blood cells in patients with chronic kidney disease

Various sleep abnormalities, such as delayed sleep onset, frequent awakening and daytime sleepiness, deteriorate the quality of life in patients with chronic kidney disease (CKD), including those on haemodialysis (HD). Although there are some candidate causative molecules in the central nervous system, the contribution of peripheral blood cells (PBCs) remains unclear. In this study, we performed polysomnographic analysis in CKD patients and used PBCs to examine the expression of genes related to sleep and wakefulness states. Polysomnographic analysis was performed in 9 CKD patients and 6 controls. Genes related to sleep and wakefulness were evaluated by RNA microarray in 19 subjects, including CKD patients and control subjects. Polysomnographic analysis revealed that the duration of the rapid eye movement (REM)/non-REM phases during total sleep time was different between CKD patients and healthy controls. In mRNA microarray evaluation, hierarchical clustering analysis showed different patterns of sleep-related gene expression in HD patients. mRNA expression levels of GABA receptor (GABBR2), noradrenaline receptor (ADRA1A), dopamine receptor (DRD1) and histamine receptor (HRH1) showed an inverse correlation with renal function. Moreover, the mRNA expression of orexin and its receptor (HCRTR1 and HCRTR2) was also inversely correlated with renal function. These data indicate that the expression of sleep-related genes in PBCs of CKD patients may be associated with sleep abnormalities.