Lindberg, Olof

AbstractBackgroundThe relation between cerebrospinal fluid (CSF) biomarkers of Alzheimer’s disease (AD) and neurodegeneration and brain regions of relevance for very early pathological processes in AD is poorly understood. This study aims to investigate cross‐sectional associations between the CSF biomarkers amyloid‐β1‐42 (Aβ42), total‐tau (T‐tau), phosphorylated‐tau (P‐tau), neurogranin (Ng) and neurofilament light (NfL) protein and normalized intracranial volumes of the hippocampus, amygdala, entorhinal cortex and basal forebrain observed on structural magnetic resonance imaging (MRI) in cognitively healthy 70‐year olds from the general population.MethodThe analyses included 226 cognitively normal individuals (clinical dementia rating of zero), examined during 2014‐2016 as part of the population‐based Gothenburg H70 Birth Cohort Studies in Sweden. The study participants had undergone lumbar puncture examination to extract CSF samples for biomarker measurements (pg/mL), MRI scan (volumes in mm³), and apolipoprotein E (APOE) genotyping. Linear regressions, adjusted for sex, were used to examine potential associations.ResultElevated CSF T‐tau, P‐tau, and Ng concentrations were associated with smaller volumes of the hippocampus, amygdala, and entorhinal cortex among individuals with amyloid pathology (p = 8×10−8 – 0.04) and among APOE ε4 carriers (p = 8×10−5 – 0.04). In addition, elevated CSF T‐tau, P‐tau, and Ng concentrations were associated with larger basal forebrain among individuals without pathological Aβ42 (p = 0.001 – 0.01) and among APOE ε4 non‐carriers (p = 0.004 – 0.02).ConclusionThe results of our study suggest that among cognitively normal adults who have amyloid pathology or genetic susceptibility to AD, there are associations between axonal degeneration, tangle pathology, and synapse loss and decreased volumes of AD vulnerable brain regions. The associations between elevated CSF biomarkers and larger basal forebrain in cognitively normal individuals were unexpected, but could possibly be explained by compensatory mechanisms or an inflammatory response (generating neuronal or glial swelling) as a very early reaction to the presence of increased levels of tau and Ng. Our findings highlight the clinical pathophysiological relevance of CSF biomarkers of AD and neurodegeneration and how they relate to AD specific brain regions seen on structural MRI in 70‐year‐olds that may be at risk to develop dementia.

Abstract Introduction As cerebrospinal fluid (CSF) neurofilament light protein (NfL) and the CSF/serum albumin ratio (Q Alb ) are used in the clinical routine, the impact of demographic factors on these biomarkers is important to understand. Methods Participants were derived from two Swedish samples: the population‐based H70 Study (n = 308, age 70) and a clinical routine cohort (CSF NfL, n = 8995, Q Alb , n = 39252, age 0 to 95). In the population‐based study, Q Alb and NfL were examined in relation to sex, cardiovascular risk factors, and cerebral white matter lesions (WMLs). In the clinical cohort, Q Alb and NfL sex differences were tested in relation to age. Results Men had higher Q Alb and NfL concentrations and had higher Q Alb and NfL concentrations from adolescence throughout life. NfL was not related to WML, but Q Alb correlated positively with WMLs. Discussion The CSF NfL sex difference could not be explained by vascular pathology. Future studies should consider using different reference limits for men and women.

AbstractBackgroundCSF neurofilament light protein (NfL) is an important biomarker in several neurologic diseases. CSF NfL concentrations are known to increase with age, but sex differences have been less examined. The CSF/serum albumin ratio (QAlb) is a biomarker for blood‐brain barrier integrity, which has previously been found to be higher in men. As NfL and QAlb are used in clinical routine, the impact of demographic factors on these biomarkers is important to understand.MethodParticipants were derived from two samples. The first was a population‐based cohort of 308 70‐year olds from the Gothenburg H70 Birth Cohort Study, Sweden. The second data set comprised CSF NfL and QAlb results from 8995 and 39252 subjects respectively, generated in clinical practice between 2005‐2012 in Gothenburg, Sweden. In the population‐based study, QAlb and NfL concentrations were examined in relation to sex, cardiovascular risk factors, and MRI signs of cerebral white matter lesions. In the clinical routine cohort, sex differences in QAlb and NfL were tested in relation to age.ResultIn the population‐based sample, men had higher QAlb and NfL concentrations than women. NfL was not related to cerebral vascular pathology, but QAlb correlated positively with several measures of white matter lesions. In the clinical routine cohort, men also had higher QAlb and NfL concentrations from adolescence and throughout life.ConclusionQAlb ratios and CSF NfL levels are higher in men throughout life. The CSF NfL sex difference could not be explained by vascular pathology. Future studies should consider using different reference limits for men and women.