The German National Cohort (NAKO): Overview and Current State

The presentation aims to give an overview of design, methods and first results of the German National Cohort (NAKO), the largest cohort study in Germany. NAKO is a multidisciplinary, population-based cohort study that provides a central resource for population-based epidemiologic research. NAKO aims to investigate the development and aetiology of diseases, identify risk factors and enhance early detection and prevention of diseases with a focus on diabetes, cancer, cardiovascular, pulmonary, neuropsychiatric and infectious diseases. Between 2014 and 2019, a total of 205,415 persons aged 20 - 74 years were recruited and examined at 18 study centres across Germany. The participants were invited to their local study centre to participate in a face-to-face interview, complete self-administered computer-based questionnaires, undergo a battery of biomedical examinations, and provide various biosamples. In addition, whole-body Magnet Resonance Imaging (MRI) was performed in 30,861 participants on dedicated 3 Tesla MRI scanners at 5 study centres. In 4-5 year intervals, all study participants are re-invited for examinations at the study centres. The programme for the first re-examination (including MRI scanning) was similar to the baseline programme. Thereby, longitudinal information on changes in risk factor profiles and in vascular, cardiac, metabolic, neurocognitive, pulmonary and sensory function is collected. During the COVID-19 pandemic, questions on pandemic-related aspects including the history of infection, severity and long-term health impacts of COVID-19 were added to the examination programme. Since October 2018, 77,896 participants have been re-examined, including 11,382 with additional MRI examination. A supplemental COVID-19 questionnaire was completed by 161,849 participants of NAKO during the first COVID-19-related lockdown in Spring 2020.

[Segmental necrotizing colitis in a patient with E. coli O104:H4 infection]

A 29-year-old man presented with abdominal cramps and bloody diarrhoea. Blood tests revealed elevated C-reactive protein (21.3 mg/dL; normal range 0.01 - 0. 82 mg/dL) and white blood cells (28200/μL, normal range 4000 - 10000/μL). Stool tests were negative for enteropathogenic bacteria and Clostridium difficile toxins A/B. Ultrasound and computed tomography showed massive swelling of the transverse colon and right colonic flexure. At endoscopy, circular necrosis of the mucosa was encountered in the proximal segments of the colon whereas distal parts of the organ showed patchy inflammation of minor severity. Extended stool testing identified Escherichia coli type O104:H4 as the causative microorganism. There was no evidence for haemolytic uraemic syndrome. Under conservative treatment the patient recovered clinically, serologically and endoscopically. At follow-up endoscopy, longitudinal ulcers and vital mucosa were present. In this case report the segmental pattern of mucosal necrosis in a patient with EHEC infection is noteworthy.

Histamine excites neurones in the human submucous plexus through activation of H1, H2, H3 and H4 receptors

Histamine is a major mast cell mediator of immunoneural signalling in the gut and mast cells play a role in the pathophysiology of functional and inflammatory bowel diseases. Histamine receptors are therefore promising drug targets to treat gut disorders. We aimed to study the so far unknown effect of histamine on neural activity in the human enteric nervous system (ENS) and to identify the pharmacology of histamine response. We used fast imaging techniques in combination with the potentiometric dye di-8-ANEPPS to monitor directly membrane potential changes and thereby neuronal excitability in the human submucous plexus from surgical specimens of 110 patients (2137 neurones, 273 ganglia). Local microejection of histamine resulted in action potential discharge in 37% of neurones. This excitatory effect was mimicked by the H(1) agonist HTMT-dimaleat, H(2) agonist dimaprit, H(3) agonist (R)-(-)-alpha-methylhistamine and H(4) agonist 4-methylhistamine. The excitatory actions of the agonists were specifically and selectively blocked by the H(1), H(2), H(3) or H(4) receptor antagonists pyrilamine, ranitidine, clobenpropit or J1-[(5-chloro-1H-indol-2-yl)carbonyl]-4-methylpiperazine (JNJ 7777120), respectively. Clobenproprit reduced the excitatory response to histamine. Unlike in the guinea-pig ENS (R)-(-)-alpha-methylhistamine had no presynaptic actions in human submucous plexus. Application of agonists revealed receptor clustering which was as follows: 29% H(1)/H(3), 27% H(2), 20% H(1)/H(2)/H(3), 10% H(3), 7% H(1)/H(2) and 7% H(2)/H(3). Histamine excites human enteric neurones and this effect involves all four histamine receptors; most striking was the identification of an excitatory H(3) mediated component and the discovery of H(4) mediated neuronal excitation. These data may form the basis of identification of new targets to treat inflammatory and functional gut disorders.