Divergent roles of red cell arginase in humans and mice: RBC Arg1 KO mice show preserved systemic l-arginine bioavailability and infarct size in vivo.

In humans and other primates, red blood cells (RBCs) constitutively express high levels of liver-type arginase 1 (Arg1), which regulates systemic l-arginine and nitric oxide (NO) bioavailability, particularly under pathological conditions such as sickle cell disease. In contrast, the role of RBC Arg1 in mice in vivo remains poorly defined. Here, we investigated the contribution of RBC Arg1 to systemic l-arginine metabolism, NO bioavailability, and cardioprotection following acute myocardial infarction in vivo.

Best practices for blood collection and anaesthesia in mice: Selection, application and reporting.

Blood collection in mice is a common procedure in biomedical research. The choice of blood collection method and the need for analgesia and/or anaesthesia depend on multiple factors, including the experimental setup, animal welfare considerations and the intended downstream analyses. This minireview describes key non-surgical and surgical blood collection techniques, the appropriate use of analgesia and anaesthesia, and the best practice for documentation and adherence to reporting standards in animal studies.

Biochemistry, pharmacology, and in vivo function of arginases.

The enzyme arginase catalyzes the hydrolysis of l-arginine into l-ornithine and urea. The 2 existing isoforms Arg1 and Arg2 exhibit different cellular localizations and metabolic functions. Arginase activity is crucial for nitrogen detoxification in the urea cycle, synthesis of polyamines, and control of l-arginine bioavailability and nitric oxide (NO) production.

Generation and characterization of a conditional eNOS knock out mouse model for cell-specific reactivation of eNOS in gain-of-function studies.

Nitric oxide (NO) produced by endothelial nitric oxide synthase (eNOS) in the vessel wall regulates blood pressure and cardiovascular hemodynamics. In this study, we generated conditional eNOS knock out (KO) mice characterized by a duplicated/inverted exon 2 flanked with two pairs of loxP regions (eNOS); a Cre-recombinase activity induces cell-specific reactivation of eNOS, as a result of a flipping of the inverted exon 2 (eNOS). This work aimed to test the efficiency of the Cre-mediated cell-specific recombination and the resulting eNOS expression/function.

The hemodynamic response to nitrite is acute and dependent upon tissue perfusion.

In the vasculature, nitric oxide (NO) is produced in the endothelium by endothelial nitric oxide synthase (eNOS) and is critical for the regulation of blood flow and blood pressure. Blood flow may also be regulated by the formation of nitrite-derived NO catalyzed by hemoproteins under hypoxic conditions. We sought to investigate whether nitrite administration may affect tissue perfusion and systemic hemodynamics in WT and eNOS knockout mice.

Determination of Nitric Oxide and Its Metabolites in Biological Tissues Using Ozone-Based Chemiluminescence Detection: A State-of-the-Art Review.

Ozone-based chemiluminescence detection (CLD) has been widely applied for determining nitric oxide (NO) and its derived species in many different fields, such as environmental monitoring and biomedical research. In humans and animals, CLD has been applied to determine exhaled NO and NO metabolites in plasma and tissues. The main advantages of CLD are high sensitivity and selectivity for quantitative analysis in a wide dynamic range.

Red blood cell endothelial nitric oxide synthase: A major player in regulating cardiovascular health.

Red blood cells (RBCs) have traditionally been seen as simple carriers of gases and nutrients in the body. One important non-canonical function of RBCs in the cardiovascular system is the regulation of nitric oxide (NO) metabolism. It has been shown that RBCs can scavenge NO, transport NO metabolites and produce NO in hypoxic conditions, thereby inducing hypoxic vasodilation.

Complexing the Marine Sesquiterpene Euplotin C by Means of Cyclodextrin-Based Nanosponges: A Preliminary Investigation.

Euplotin C is a sesquiterpene of marine origin endowed with significant anti-microbial and anti-tumor properties. Despite the promising functional profile, its progress as a novel drug candidate has failed so far, due to its scarce solubility and poor stability in aqueous media, such as biological fluids. Therefore, overcoming these limits is an intriguing challenge for the scientific community.

Using diaminofluoresceins (DAFs) in nitric oxide research.

Diaminofluoresceins (DAFs) are fluorescent probes widely applied to measure nitric oxide (NO) formation in cells and tissues. The main advantages of these compounds are their availability and low cost, and the general availability of instruments able to detect green fluorescence in all laboratories; these include fluorimeters, flow cytometers, and fluorescent microscopes. What made these molecules particularly interesting for many scientists approaching the NO field is that they are apparently very easy to use, as compared with other techniques requiring specific instrumentation and knowledge like chemiluminescence and electron paramagnetic resonance.

Red Blood Cell and Endothelial eNOS Independently Regulate Circulating Nitric Oxide Metabolites and Blood Pressure.

Background: Current paradigms suggest that nitric oxide (NO) produced by endothelial cells (ECs) through endothelial nitric oxide synthase (eNOS) in the vessel wall is the primary regulator of blood flow and blood pressure. However, red blood cells (RBCs) also carry a catalytically active eNOS, but its role is controversial and remains undefined. This study aimed to elucidate the functional significance of RBC eNOS compared with EC eNOS for vascular hemodynamics and nitric oxide metabolism.