Increased Blood-Brain Barrier Permeability and Cognitive Impairment in Patients With ESKD

Abstract

Background and AimsChronic kidney disease (CKD) is associated with an increased risk of cognitive impairment. This cognitive impairment is associated with an increased permeability of blood-brain barrier (BBB) in rodents with CKD, linked to activation of aryl hydrocarbon receptor (AhR) by indoxyl sulphate (IS). The objective of BREIN study is to confirm the increased BBB permeability in humans with CKD. MethodThe BREIN comparative study (NCT04328415) prospectively included patients with end-stage kidney disease (ESKD), and healthy volunteers (Ctrl) matched in age, sex, and educational level to a patient. In all participants, BBB permeability was quantified by brain 99mTc-DTPA SPECT/CT as percentage of injected activity (%IA). A battery of neuro-cognitive tests was performed, serum uremic toxins accumulation and AhR activation were assessed. ResultsFifteen ESKD patients and 14 healthy volunteers were analysed. ESKD patients had higher BBB permeability compared to controls: 0.29±0.07 vs. 0.14±0.06 %IA, p=0.002. ESKD patients displayed lower MoCA score: 22.0±5.0 vs. 27.3 ± 2.8, p=0.008, impaired short-term memory (doors test): 12.5±3.4 vs. 16.5±3.4, p=0.005, higher Beck depression score 8.1±9.1 vs. 2.7±3.4, p=0.046, and slightly more daily cognitive complaints: 42.5±29.3 vs. 29.8±14.0 p=0.060. ESKD patients displayed higher IS levels (86.1±48.4 vs. 3.2±1.7 μmol/L, p=0.001) and AhR activating potential (37.7±17.8% vs. 24.7±10.4%, p=0.027). BBB permeability was inversely correlated with MoCA score (r=-0.60, 95%CI [-0.772; -0.339], p=0.001) in the overall population. ConclusionESKD patients display an increased BBB permeability compared to matched healthy volunteers. Association with uremic toxins and cognitive impairment needs to be assessed in larger cohorts of patients.