An Approach to Intersectionally Target Mature Enteroendocrine Cells in the Small Intestine of Mice.

Enteroendocrine cells (EECs) constitute only a small proportion of Villin-1 (Vil1)-expressing intestinal epithelial cells (IECs) of the gastrointestinal tract; yet, in sum, they build the largest endocrine organ of the body, with each of them storing and releasing a distinct set of peptides for the control of feeding behavior, glucose metabolism, and gastrointestinal motility. Like all IEC types, EECs are continuously renewed from intestinal stem cells in the crypt base and terminally differentiate into mature subtypes while moving up the crypt-villus axis. Interestingly, EECs adjust their hormonal secretion according to their migration state as EECs receive altering differentiation signals along the crypt-villus axis and thus undergo functional readaptation. Cell-specific targeting of mature EEC subtypes by specific promoters is challenging because the expression of EEC-derived peptides and their precursors is not limited to EECs but are also found in other organs, such as the brain (e.g., Cck and Sst) as well as in the pancreas (e.g., Sst and Gcg). Here, we describe an intersectional genetic approach that enables cell type-specific targeting of functionally distinct EEC subtypes by combining a newly generated Dre-recombinase expressing mouse line (Vil1-2A-DD-Dre) with multiple existing Cre-recombinase mice and mouse strains with rox and loxP sites flanked stop cassettes for transgene expression. We found that transgene expression in triple-transgenic mice is highly specific in I but not D and L cells in the terminal villi of the small intestine. The targeting of EECs only in terminal villi is due to the integration of a defective 2A separating peptide that, combined with low EEC intrinsic Vil1 expression, restricts our Vil1-2A-DD-Dre mouse line and the intersectional genetic approach described here only applicable for the investigation of mature EEC subpopulations.

German Cardiac Arrest Registry (G-CAR)-results of the pilot phase.

BACKGROUND: In Europe, more than 300,000 persons per year experience out-of-hospital cardiac arrest (OHCA). Despite medical progress, only few patients survive with good neurological outcome. For many issues, evidence from randomized trials is scarce. OHCA often occurs for cardiac causes. Therefore, we established the national, prospective, multicentre German Cardiac Arrest Registry (G-CAR). Herein, we describe the first results of the pilot phase. RESULTS: Over a period of 16 months, 15 centres included 559 consecutive OHCA patients aged ≥ 18 years. The median age of the patients was 66 years (interquartile range 57;75). Layperson resuscitation was performed in 60.5% of all OHCA cases which were not observed by emergency medical services. The initial rhythm was shockable in 46.4%, and 29.1% of patients had ongoing CPR on hospital admission. Main presumed causes of OHCA were acute coronary syndromes (ACS) and/or cardiogenic shock in 54.8%, with ST-elevation myocardial infarction being the most common aetiology (34.6%). In total, 62.9% of the patients underwent coronary angiography; percutaneous coronary intervention (PCI) was performed in 61.4%. Targeted temperature management was performed in 44.5%. Overall in-hospital mortality was 70.5%, with anoxic brain damage being the main presumed cause of death (38.8%). Extracorporeal cardiopulmonary resuscitation (eCPR) was performed in 11.0%. In these patients, the in-hospital mortality rate was 85.2%. CONCLUSIONS: G-CAR is a multicentre German registry for adult OHCA patients with a focus on cardiac and interventional treatment aspects. The results of the 16-month pilot phase are shown herein. In parallel with further analyses, scaling up of G-CAR to a national level is envisaged. Trial registration ClinicalTrials.gov identifier: NCT05142124.