Frailty and cognitive impairment in chronic kidney disease

Abstract

Recently, accumulating evidence has been published on cognitive impairment in patients with chronic kidney disease (CKD). It has been shown that brain atrophy is prominent in patients receiving hemodialysis or peritoneal dialysis, and the significant association between brain atrophy and frequency of rapid decline in blood pressure during the hemodialysis session was documented. Recently, we reported a close association between gray matter atrophy and executive dysfunction in CKD patients, suggesting the importance of preventing brain atrophy for the prevention of cognitive impairment. It has been reported that frailty, a common geriatric syndrome that embodies an elevated risk of catastrophic declines in health and function among older adults, is associated with poor cognitive function, cognitive decline, and dementia in older adults with and without CKD. A number of traditional and nontraditional vascular factors and nonvascular factors are strongly implicated in the pathophysiological relationship among CKD, cognitive decline, and frailty. Several recent randomized controlled trials of elderly individuals without dementia have demonstrated that exercise training improved cognitive function with an increase in brain volume. Experimental studies have shown that exercise decreased the amount of β-amyloid (Aβ) oligomers in addition to depositing Aβ in the brain. Alternatively, some other studies have demonstrated that physical training increases angiogenesis, synaptogenesis, and neurogenesis, especially in hippocampus and in gyrus dentatus and initiates the upregulation of numerous neurotrophic factors such as BDNF and IGF-1 in the brain, especially in hippocampus. Accordingly, physical exercise training should be implemented to prevent and treat frailty and cognitive impairment in the elderly CKD patients.