Metabolische Phänotypisierung von Mausmutantenlinien im Rahmen des metabolischen Labors der Deutschen Mausklinik

Nach dem erfolgreichen Abschluss des humanen Genomprojekts liegt das Interesse der biomedizinischen Forschung heute besonders in der Aufklärung der Funktion der Gene. Mausmutantenlinien sind für eine detaillierte Analyse der Korrelation von Genotyp und Phänotyp prädestiniert. Mit der German Mouse Clinic wurde ein Phänotypisierungszentrum etabliert, in dessen Rahmen Mausmutantenlinien im Hochdurchsatzverfahren einer effizienten und standardisierten Untersuchung aller Körpersysteme unterzogen werden, um so einen potentiellen Phänotyp detektieren zu können. Als Modul der GMC bestand die Aufgabe des metabolischen Screens in der Etablierung eines Versuchsaufbaus, der eine systematische, standardisierte und umfassende metabolische Phänotypisierung von Mausmodellen gewährleistet. Ziel der Arbeit war es, Leitlinien zur metabolischen Phänotypisierung von Mausmutantenlinien zu entwickeln. Dies beinhaltete die metabolische Charakterisierung von sechs Inzuchtlinien als Grundlage der Phänotypisierung von Mausmutantenlinien,die Auswertung der Phänotypisierungsdaten von 80 Mausmutantenlinien im Gesamtüberblick, die Bewertung der chronischen und akuten Futterreduktion als Challenge-Experiment und eine detaillierte metabolische Charakterisierung der ENU Mausmutantenlinie HWE007 anhand des Methodenspektrums des Primär-, Sekundär- und Tertiärscreens des metabolischen Labors

Loss of the Actin Remodeler Eps8 Causes Intestinal Defects and Improved Metabolic Status in Mice

In a variety of organisms, including mammals, caloric restriction improves metabolic status and lowers the incidence of chronic-degenerative diseases, ultimately leading to increased lifespan. Here we show that knockout mice for Eps8, a regulator of actin dynamics, display reduced body weight, partial resistance to age- or diet-induced obesity, and overall improved metabolic status. Alteration in the liver gene expression profile, in behavior and metabolism point to a calorie restriction-like phenotype in Eps8 knockout mice. Additionally, and consistent with a calorie restricted metabolism, Eps8 knockout mice show increased lifespan. The metabolic alterations in Eps8 knockout mice correlated with a significant reduction in intestinal fat absorption presumably caused by a 25% reduction in intestinal microvilli length. Our findings implicate actin dynamics as a novel variable in the determination of longevity. Additionally, our observations suggest that subtle differences in energy balance can, over time, significantly affect bodyweight and metabolic status in mice

Experimental Inoculation of Juvenile Rhesus Macaques with Primate Enteric Caliciviruses

Tissue culture-adapted Tulane virus (TV), a GI.1 rhesus enteric calicivirus (ReCV), and a mixture of GII.2 and GII.4 human norovirus (NoV)-containing stool sample were used to intrastomacheally inoculate juvenile rhesus macaques (Macaca mulatta) in order to evaluate infection caused by these viruses. METHODOLOGY & FINDINGS: Two of the three TV-inoculated macaques developed diarrhea, fever, virus-shedding in stools, inflammation of duodenum and 16-fold increase of TV-neutralizing (VN) serum antibodies but no vomiting or viremia. No VN-antibody responses could be detected against a GI.2 ReCV strain FT285, suggesting that TV and FT285 represent different ReCV serotypes. Both NoV-inoculated macaques remained asymptomatic but with demonstrable virus shedding in one animal. Examination of duodenum biopsies of the TV-inoculated macaques showed lymphocytic infiltration of the lamina propria and villous blunting. TV antigen-positive (TV+) cells were detected in the lamina propria. In most of the TV+ cells TV co-localized perinuclearly with calnexin--an endoplasmic reticulum protein. A few CD20+TV+ double-positive B cells were also identified in duodenum. To corroborate the authenticity of CD20+TV+ B cells, in vitro cultures of peripheral blood mononuclear cells (PBMCs) from healthy macaques were inoculated with TV. Multicolor flow cytometry confirmed the presence of TV antigen-containing B cells of predominantly CD20+HLA-DR+ phenotype. A 2-log increase of viral RNA by 6 days post inoculation (p<0.05) suggested active TV replication in cultured lymphocytes.Taken together, our results show that ReCVs represent an alternative cell culture and animal model to study enteric calicivirus replication, pathogenesis and immunity

Neurobeachin, a Regulator of Synaptic Protein Targeting, Is Associated with Body Fat Mass and Feeding Behavior in Mice and Body-Mass Index in Humans

Neurobeachin (Nbea) regulates neuronal membrane protein trafficking and is required for the development and functioning of central and neuromuscular synapses. In homozygous knockout (KO) mice, Nbea deficiency causes perinatal death. Here, we report that heterozygous KO mice haploinsufficient for Nbea have higher body weight due to increased adipose tissue mass. In several feeding paradigms, heterozygous KO mice consumed more food than wild-type (WT) controls, and this consumption was primarily driven by calories rather than palatability. Expression analysis of feeding-related genes in the hypothalamus and brainstem with real-time PCR showed differential expression of a subset of neuropeptide or neuropeptide receptor mRNAs between WT and Nbea+/− mice in the sated state and in response to food deprivation, but not to feeding reward. In humans, we identified two intronic NBEA single-nucleotide polymorphisms (SNPs) that are significantly associated with body-mass index (BMI) in adult and juvenile cohorts. Overall, data obtained in mice and humans suggest that variation of Nbea abundance or activity critically affects body weight, presumably by influencing the activity of feeding-related neural circuits. Our study emphasizes the importance of neural mechanisms in body weight control and points out NBEA as a potential risk gene in human obesity

Use of Metformin, Pre-mixed Insulin and Glucagon-Like Peptide-1 Receptor Agonist as a Therapeutic Approach for Uncontrolled Type 2 Diabetes Mellitus

Objective: To explore the use of premixed insulin, glucagon-like peptide-1 receptor agonist (GLP-1 RA) and metformin as a combination therapy for Type 2 Diabetes Mellitus (T2DM) over 12 months. Methods: All adult patients with T2DM who had been given premixed insulin and a form of GLP-1-RA simultaneously at our outpatient clinic were selected for retrospective review. We reviewed Hemoglobin A1c (HbA1c), weight, cumulative daily insulin dose, and adverse events over 12 months. Results: A total of 72 patients received premixed insulin and GLP-1 RA with 32 patients meeting inclusion criteria. Average duration of T2DM was 14.2 (Standard Deviation [SD] 7.1) years. Mean HbA1c at baseline was 10.5%±2.1 (91 mmol/mol). At 12 months mean HbA1c was 8.3%±1.9 (67 mmol/mol). Mean HbA1c change after 12 months was -2.2 (95% Confidence Interval [CI] -3.433 to -1.014; p \u3c 0.0001). At 12 months, cumulative insulin dose was 33.3 units less than total insulin dose prior to therapy change (CI -57.13 to -9.46; P = 0.0030). Average weight loss at 12 months was -2.2kg (CI -27.6 to 37.6, p = 0.9293). After 12 months, 61% (19 out of 31) had HbA1c ≤ 8% (64 mmol/mol). Of note, adverse events were seen in six additional patients not included in analysis as they stopped regimen after \u3c3 months. Conclusion: Despite decreasing cumulative daily dose of insulin, patients with historically uncontrolled T2DM using metformin, premixed insulin and GLP-1 RA had improved glycemic control over 12 months. Prospective randomized studies need to be done to assess the benefit of this combination of available medication therapy

Outpatient Follow-up as Predictor of Readmission Rates and Glucose Control in Patients Hospitalized for Diabetes

Background: Diabetes is a chronic disease with increasing prevalence. We hypothesize that a significant percent of patients with a primary diagnosis of diabetes/diabetes-related complications after hospitalization at George Washington University Hospital (GWUH) would have no specific follow-up and overall glucose control would be poor after discharge. Methods: This is a retrospective study evaluating the rate of follow-up for diabetes after hospitalization at GWUH for a primary diagnosis of diabetes/diabetes-related complications. There were 4266 GWUH admissions with a primary/secondary diagnosis of diabetes from June 2014 to June 2015. Chart review of patients (289) with a hospital admission for a primary diagnosis of diabetes/diabetes-related complications was conducted with assessment of readmission rates and overall glucose control after discharge. Discharge instructions/summaries from the hospital were reviewed for instructions/arranged appointments for follow-up. Follow-up rate was evaluated. Hemoglobin A1c during admission or within 180 days of admission as well as 90-180 days post-admissions were assessed. Hospital readmission rates were assessed at 30, 60, 90, and 180 days. Results: The readmission rate for a primary diagnosis of diabetes was 7.27% at 30 days and 28.02% at 90 days while overall readmissions for any cause at 30 days was 15.2% and at 90 days was 30.1%. 78.9% patients had A1c within 180 days of admissions/during admission. 21.8% had A1c \u3e 10% and 21.5% \u3e8%. Concerning follow-up, 71.47% had directions to follow-up with primary care providers. 67.08% patients has follow-up arranged with primary care providers prior to discharge; 40% of those that had follow-up arranged actually followed up compared to 17% that actually followed up when follow-up was not arranged (P = .0036). Of the 319 patients, 200 had follow up. Hemoglobin A1c within 90-180 days after admission. A1c was \u3e10% for 37.1% and 59.6% for \u3e8%. Discussion: Although limited by the review at a single institution in a metropolitan center with multiple health care systems, our data showed a significant percent of patients with a primary diagnosis of diabetes/diabetes-related complications were re-admitted, often did not have specific follow-up or complete follow-up as instructed, and overall glucose control remained poor following admission. Conclusion: To improve long term health outcomes in hospitalized patients with diabetes, protocols to ensure follow-up need to be implemented