RNA-Based Strategies for Cardiac Reprogramming of Human Mesenchymal Stromal Cells.

Multipotent adult mesenchymal stromal cells (MSCs) could represent an elegant source for the generation of patient-specific cardiomyocytes needed for regenerative medicine, cardiovascular research, and pharmacological studies. However, the differentiation of adult MSC into a cardiac lineage is challenging compared to embryonic stem cells or induced pluripotent stem cells. Here we used non-integrative methods, including microRNA and mRNA, for cardiac reprogramming of adult MSC derived from bone marrow, dental follicle, and adipose tissue. We found that MSC derived from adipose tissue can partly be reprogrammed into the cardiac lineage by transient overexpression of GATA4, TBX5, MEF2C, and MESP1, while cells isolated from bone marrow, and dental follicle exhibit only weak reprogramming efficiency. qRT-PCR and transcriptomic analysis revealed activation of a cardiac-specific gene program and up-regulation of genes known to promote cardiac development. Although we did not observe the formation of fully mature cardiomyocytes, our data suggests that adult MSC have the capability to acquire a cardiac-like phenotype when treated with mRNA coding for transcription factors that regulate heart development. Yet, further optimization of the reprogramming process is mandatory to increase the reprogramming efficiency.

18F-FDG PET-Based Imaging of Myocardial Inflammation Predicts a Functional Outcome Following Transplantation of mESC-Derived Cardiac Induced Cells in a Mouse Model of Myocardial Infarction.

Cellular inflammation following acute myocardial infarction has gained increasing importance as a target mechanism for therapeutic approaches. We sought to investigate the effect of syngeneic cardiac induced cells (CiC) on myocardial inflammation using 18F-FDG PET (Positron emission tomography)-based imaging and the resulting effect on cardiac pump function using cardiac magnetic resonance (CMR) imaging in a mouse model of myocardial infarction. Mice underwent permanent left anterior descending coronary artery (LAD) ligation inducing an acute inflammatory response. The therapy group received an intramyocardial injection of 106 CiC into the border zone of the infarction. Five days after myocardial infarction, 18F-FDG PET was performed under anaesthesia with ketamine and xylazine (KX) to image the inflammatory response in the heart. Flow cytometry of the mononuclear cells in the heart was performed to analyze the inflammatory response. The effect of CiC therapy on cardiac function was determined after three weeks by CMR. The 18F-FDG PET imaging of the heart five days after myocardial infarction (MI) revealed high focal tracer accumulation in the border zone of the infarcted myocardium, whereas no difference was observed in the tracer uptake between infarct and remote myocardium. The CiC transplantation induced a shift in 18F-FDG uptake pattern, leading to significantly higher 18F-FDG uptake in the whole heart, as well as the remote area of the heart. Correspondingly, high numbers of CD11+ cells could be measured by flow cytometry in this region. The CiC transplantation significantly improved the left ventricular ejection function (LVEF) three weeks after myocardial infarction. The CiC transplantation after myocardial infarction leads to an improvement in pump function through modulation of the cellular inflammatory response five days after myocardial infarction. By combining CiC transplantation and the cardiac glucose uptake suppression protocol with KX in a mouse model, we show for the first time, that imaging of cellular inflammation after myocardial infarction using 18F-FDG PET can be used as an early prognostic tool for assessing the efficacy of cardiac stem cell therapies.

Novel monoclonal antibodies that bind to wild and fixed rabies virus strains.

Ten monoclonal antibodies (MAbs) against rabies virus, including IgG3κ, IgG2aκ, IgMκ, and an IgG2bκ isotype, were produced and characterized using neutralization, ELISA, immunodot-blot, and immunofluorescence assays. MAb 8D11, which recognized rabies virus glycoprotein, was found to neutralize rabies virus in vitro. When submitted to an immunofluorescence assay, seven MAbs showed different reactivity against 35 Brazilian rabies virus isolates. Three MAbs (LIA 02, 3E6, and 9C7) only failed to recognize one or two virus isolates, whereas MAb 6H8 was found to be reactive against all virus isolates tested. MAbs were also evaluated for their immunoreactivity against fixed rabies virus strains present in human and veterinary commercial vaccines. MAbs LIA 02, 6H8, and 9C7 reacted against all vaccine strains, while the remaining MAbs recognized at least 76% of vaccine strains tested. This research provides a set of MAbs with potential application for improving existing or developing new diagnostic tests and immunoassays.

Shorter duration of oral N -Acetylcysteine therapy for acute acetaminophen overdose.

STUDY OBJECTIVE: We sought to evaluate the safety and efficacy of a shorter N -acetylcysteine (NAC) regimen in the treatment of acute acetaminophen overdose. METHODS: We performed a retrospective case series in a large urban county hospital. Of 305 patients identified through the emergency department, 75 patients met the criteria inclusion: an acute overdose ingestion, serum acetaminophen concentration in toxic range according to the Rumack-Matthew nomogram, and oral NAC treatment initiated within 24 hours of the ingestion. The regional poison control center recommended oral treatment with NAC 140 mg/kg, followed by maintenance doses of 70 mg/kg every 4 hours until the serum acetaminophen level was no longer detectable, rather than the standard 72-hour treatment regimen. RESULTS: The primary outcome measure was the development of hepatotoxicity. Twenty-five (33.3%) patients were treated for a period of less than 24 hours, 25 (33.3%) were treated for 24 to 36 hours, and 25 (33.3%) were treated for 37 to 64 hours; the mean and median duration of treatment was 31 hours. None of the patients treated for less than 24 hours had evidence of hepatotoxicity (aspartate aminotransferase [AST] or alanine aminotransferase [ALT] level >1,000 IU/L); hepatotoxicity developed in 2 (8%) patients treated for 24 to 36 hours and 4 (16%) patients treated for 37 to 64 hours. There were no deaths or patients who received liver transplantation. The overall incidence of hepatotoxicity in our patients was similar to that found in other protocols with administration of oral NAC for 72 hours or intravenous NAC for 20 or 48 hours. CONCLUSION: This observational study suggests that a shorter course of oral NAC therapy in patients who do not show evidence of hepatotoxicity within 36 hours of an acute acetaminophen overdose is safe and effective. [Woo OF, Mueller PD, Olson KR, Anderson IB, Kim SY. Shorter duration of oral N -acetylcysteine therapy for acute acetami-nophen overdose. Ann Emerg Med . April 2000;35:363-368.].