Biochemical markers of brain damage, e.g. ischemic stroke, should reflect the volume of irreversibly damaged brain parenchyma and the clinical outcome in a single patient in order to allow estimation of prognosis at an early stage. Tau protein, which derives predominantly from neurons and axons, is elevated in the cerebrospinal fluid of patients with neurodegenerative disease. This makes tau protein a potential marker of neuronal/axonal injury. In order to test this hypothesis, the current study aimed at showing that tau protein is measurable in the blood after acute ischemic stroke and that it correlates with clinical disability and stroke volume. In a longitudinal prospective study we measured tau protein serum levels with an ELISA in 30 patients longitudinally after ischemic stroke. Tau protein was detectable within 5 days after ischemia in the sera of 7/20 patients with MRI-proven infarction and in 2/10 patients with transitory ischemic attack; both of them had a small infarction visible on the MRI scan. Tau protein was measurable within 6 h after symptom onset, peaked after 3–5 days and correlated with infarct volume and disability after 3 months. In conclusion, serum tau protein is a candidate marker of axonal injury. In stroke, its clinical use is limited, because it is detectable only in a proportion of patients.

BackgroundWe determined the prevalence of anti-nuclear autoantibodies (ANAs) in the German adult population and examined the association between ANAs and cardiovascular and metabolic disorders.MethodsWe used data and blood samples from the pretest phases of the German National Cohort, obtained from six of the 18 study centers (n = 1199). All centers applied standardized instruments including face-to-face interviews, anthropometric measurements and collection of blood samples. Self-reported histories of diabetes mellitus, heart attack and elevated blood cholesterol and/or lipids were recorded. Height, weight and blood pressure were measured. ANAs were detected using a semi-automated system (AKLIDES®; Medipan GmbH, Dahlewitz, Germany). A positive ANA was defined as a titer ≥ 1:80. ANA were classified as weakly (1:80 or 1:160), moderately (1:320 or 1:640) or strongly (≥1:1280) positive. Specific autoantibodies against nuclear antigens were detected with second-step assays according to the ANA staining pattern. Associations between the assessed disorders and ANA positivity and pattern were examined using sex and age-adjusted mixed-effects logistic regression models.ResultsThirty-three percent (95% confidence interval; 31–36%) of the 1196 participants (measurements could not be obtained from three samples) were ANA positive (titer ≥ 1:80). The proportions of weakly, moderately and strongly positive ANA were 29%, 3.3% and 1.3%, respectively. ANA positivity was more common among women than men across all titers (χ2, p = 0.03). ANA positivity, even when stratified according to height of titer or immunofluorescent pattern, was not associated with diabetes, elevated blood cholesterol and/or lipids, obesity or hypertension. Second-step autoantibody assays were positive in 41 of the 83 samples (49%) tested, with anti-DFS70 (n = 13) and anti-dsDNA (n = 7) being most frequent. These subgroups were too small to test for associations with the disorders assessed.ConclusionsThe prevalence of ANA positivity in the German general population was similar to values reported from other countries. Contrary to other studies, there was no association with selected self-reported and objectively measured cardiovascular and metabolic variables.

No abstract

Zusammenfassung Hintergrund Die NAKO Gesundheitsstudie ist ein bundesweites interdisziplinäres Forschungsvorhaben mit dem Ziel, die Ursachen für chronische Krankheiten und deren vorklinische Stadien zu untersuchen. Der Artikel gibt einen Überblick über das Studiendesign, die Methoden, die Teilnahme an den Untersuchungen und ihre Qualitätssicherung zur Halbzeit der Basiserhebung. Methoden Für die Basiserhebung wurden mehr als 200.000 Frauen und Männer im Alter von 20–69 Jahren aus Zufallsstichproben der Allgemeinbevölkerung in 18 Studienzentren rekrutiert (2014–2019). Die Basiserhebung beinhaltet Untersuchungen, Befragungen und Biomaterialien für alle Teilnehmerinnen und Teilnehmer (Level 1), ein erweitertes Programm für mindestens 20 % (Level 2) und eine Magnetresonanztomografie (MRT) für 30.000 Teilnehmerinnen und Teilnehmer. Sekundär- und Registerdaten werden über Krankheitsregister, Kranken- und Rentenversicherungen erhoben. Die Auswertung bezieht die Datenbasis zur Halbzeit der Basiserhebung mit 101.839 Teilnehmerinnen und Teilnehmern ein, davon 11.371 mit einer MRT-Untersuchung. Ergebnisse Die mittlere Responsequote zur Halbzeit betrug insgesamt 18 %. Die Teilnahme an den Untersuchungen lag überwiegend bei mehr als 95 %. Bei 96 % der MRT-Teilnehmerinnen und Teilnehmer konnten alle 12 MRT-Sequenzen vollständig durchgeführt werden. Der Erschließung und wissenschaftlichen Nutzung ergänzender Sekundär- und Registerdaten stimmten mehr als 90 % der Teilnehmerinnen und Teilnehmer zu. Diskussion Die Bereitschaft, möglichst alle Untersuchungsmodule durchzuführen, war trotz des zeitlichen Aufwandes außerordentlich hoch. Dadurch wird die NAKO zu einer zentralen Ressource für die epidemiologische Forschung in Deutschland. Sie wird es ermöglichen, neue Strategien zur Früherkennung, Vorhersage und Primärprävention chronischer Krankheiten zu entwickeln.

The German National Cohort (NAKO) is a multidisciplinary, population-based prospective cohort study that aims to investigate the causes of widespread diseases, identify risk factors and improve early detection and prevention of disease. Specifically, NAKO is designed to identify novel and better characterize established risk and protection factors for the development of cardiovascular diseases, cancer, diabetes, neurodegenerative and psychiatric diseases, musculoskeletal diseases, respiratory and infectious diseases in a random sample of the general population. Between 2014 and 2019, a total of 205,415 men and women aged 19–74 years were recruited and examined in 18 study centres in Germany. The baseline assessment included a face-to-face interview, self-administered questionnaires and a wide range of biomedical examinations. Biomaterials were collected from all participants including serum, EDTA plasma, buffy coats, RNA and erythrocytes, urine, saliva, nasal swabs and stool. In 56,971 participants, an intensified examination programme was implemented. Whole-body 3T magnetic resonance imaging was performed in 30,861 participants on dedicated scanners. NAKO collects follow-up information on incident diseases through a combination of active follow-up using self-report via written questionnaires at 2–3 year intervals and passive follow-up via record linkages. All study participants are invited for re-examinations at the study centres in 4–5 year intervals. Thereby, longitudinal information on changes in risk factor profiles and in vascular, cardiac, metabolic, neurocognitive, pulmonary and sensory function is collected. NAKO is a major resource for population-based epidemiology to identify new and tailored strategies for early detection, prediction, prevention and treatment of major diseases for the next 30 years.