Near infrared spectroscopy reveals brain hypoxia and cerebrovascular dysregulation in primary biliary cholangitis
Primary Biliary Cholangitis (PBC) is an autoimmune cholestatic liver disease linked to symptoms including fatigue and altered mood/cognition, indicating that chronic liver inflammation associated with PBC can impact brain function. We employed near infrared spectroscopy (NIRS), a non-invasive neuroimaging technique, to determine whether PBC patients exhibit reduced cerebral oxygen saturation (StO2) and altered patterns of microvascular cerebral blood perfusion, and whether these alterations
... associated with clinical phenotype. This observational case-control study was conducted at a tertiary hospital clinic (University of Calgary Liver Unit). Thirteen females with non-cirrhotic PBC, seven females with cirrhotic PBC, and eleven healthy female controls were recruited via physician referral and word of mouth, respectively. Near infrared spectroscopy was used to measure cerebral hemoglobin and oxygen saturation. A wavelet phase coherence method was used to estimate the coherent frequency coupling of temporal changes in cerebral hemodynamics. The PBC group demonstrated significantly reduced cerebral StO2 (p = 0.01, d = 0.84), indicating cerebral hypoxia, significantly increased cerebral deoxyhemoglobin (HHb) concentration (p < 0.01, d = 0.86), and significantly reduced hemodynamic coherence in the low-frequency band (0.08-0.15 Hz) for oxygenated hemoglobin (O2Hb) concentration (p = 0.02, d = 0.99) and tHb concentration (p = 0.02, d = 0.50), indicating alterations in cerebrovascular activity. Complete biochemical response to ursodexycholic acid (UDCA) therapy in early PBC patients was associated with increased cerebral tHb concentration and decreased hemodynamic coherence. Conclusion: Using NIRS, PBC patients were found to have hypoxia, increased cerebral hemoglobin concentration, and altered cerebrovascular activity, that were reversed in part in UDCA responders. In addition, symptoms and quality of life measures did not correlate with brain hypoxia or cerebrovascular dysregulation in PBC patients.