The discovery that mammalian cells have the ability to synthesize the free radical nitric oxide (NO) has stimulated an extraordinary impetus for scientific research in all the fields of biology and medicine. Since its early description as an endothelial-derived relaxing factor, NO has emerged as a fundamental signaling device regulating virtually every critical cellular function, as well as a potent mediator of cellular damage in a wide range of conditions. Recent evidence indicates that most of the cytotoxicity attributed to NO is rather due to peroxynitrite, produced from the diffusion-controlled reaction between NO and another free radical, the superoxide anion. Peroxynitrite interacts with lipids, DNA, and proteins via direct oxidative reactions or via indirect, radical-mediated mechanisms. These reactions trigger cellular responses ranging from subtle modulations of cell signaling to overwhelming oxidative injury, committing cells to necrosis or apoptosis. In vivo, peroxynitrite generation represents a crucial pathogenic mechanism in conditions such as stroke, myocardial infarction, chronic heart failure, diabetes, circulatory shock, chronic inflammatory diseases, cancer, and neurodegenerative disorders. Hence, novel pharmacological strategies aimed at removing peroxynitrite might represent powerful therapeutic tools in the future. Evidence supporting these novel roles of NO and peroxynitrite is presented in detail in this review.

/pdf/nitric-oxide-and-peroxynitrite-in-health-and-disease-3uuuqgfdcz.pdf

Nitric Oxide and Peroxynitrite in Health and Disease

Vascular endothelial growth factor (VEGF) is a highly specific mitogen for vascular endothelial cells. Five VEGF isoforms are generated as a result of alternative splicing from a single VEGF gene. These isoforms differ in their molecular mass and in biological properties such as their ability to bind to cell-surface heparan-sulfate proteoglycans. The expression of VEGF is potentiated in response to hypoxia, by activated oncogenes, and by a variety of cytokines. VEGF induces endothelial cell proliferation, promotes cell migration, and inhibits apoptosis. In vivo VEGF induces angiogenesis as well as permeabilization of blood vessels, and plays a central role in the regulation of vasculogenesis. Deregulated VEGF expression contributes to the development of solid tumors by promoting tumor angiogenesis and to the etiology of several additional diseases that are characterized by abnormal angiogenesis. Consequently, inhibition of VEGF signaling abrogates the development of a wide variety of tumors. The various VEGF forms bind to two tyrosine-kinase receptors, VEGFR-1 (flt-1) and VEGFR-2 (KDR/flk-1), which are expressed almost exclusively in endothelial cells. Endothelial cells express in addition the neuropilin-1 and neuropilin-2 coreceptors, which bind selectively to the 165 amino acid form of VEGF (VEGF165). This review focuses on recent developments that have widened considerably our understanding of the mechanisms that control VEGF production and VEGF signal transduction and on recent studies that have shed light on the mechanisms by which VEGF regulates angiogenesis.

Vascular endothelial growth factor (VEGF) and its receptors

Resveratrol, a constituent of red wine, has long been suspected to have cardioprotective effects. Interest in this compound has been renewed in recent years, first from its identification as a chemopreventive agent for skin cancer, and subsequently from reports that it activates sirtuin deacetylases and extends the lifespans of lower organisms. Despite scepticism concerning its bioavailability, a growing body of in vivo evidence indicates that resveratrol has protective effects in rodent models of stress and disease. Here, we provide a comprehensive and critical review of the in vivo data on resveratrol, and consider its potential as a therapeutic for humans.

Therapeutic potential of resveratrol: the in vivo evidence.

The incretin system: glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors in type 2 diabetes

The objective of this study was to determine whether endogenous nitric oxide (NO) inhibits leukocyte adhesion to vascular endothelium. This was accomplished by superfusing a cat mesenteric preparation with inhibitors of NO production, NG-monomethyl-L-arginine (L-NMMA) or NG-nitro-L-arginine methyl ester (L-NAME), and observing single (30-microns diameter) venules by intravital video microscopy. Thirty minutes into the superfusion period the number of adherent and emigrated leukocytes, the erythrocyte velocity, and the venular diameter were measured; venular blood flow and shear rate were calculated from the measured parameters. The contribution of the leukocyte adhesion glycoprotein CD11/CD18 was determined using the CD18-specific monoclonal antibody IB4. Both inhibitors of NO production increased leukocyte adherence more than 15-fold. Leukocyte emigration was also enhanced, whereas venular shear rate was reduced by nearly half. Antibody IB4 abolished the leukocyte adhesion induced by L-NMMA and L-NAME. Incubation of isolated cat neutrophils with L-NMMA, but not L-NAME, resulted in direct upregulation of CD11/CD18 as assessed by flow cytometry. Decrements in venular shear rate induced by partial occlusion of the superior mesenteric artery in untreated animals revealed that only a minor component of L-NAME-induced leukocyte adhesion was shear rate-dependent. The L-NAME-induced adhesion was inhibited by L-arginine but not D-arginine. These data suggest that endothelium-derived NO may be an important endogenous modulator of leukocyte adherence and that impairment of NO production results in a pattern of leukocyte adhesion and emigration that is characteristic of acute inflammation.

https://www.pnas.org/content/pnas/88/11/4651.full.pdf

Nitric oxide: an endogenous modulator of leukocyte adhesion.

Sustained tissue hypoxia is associated with many pathophysiological conditions, including chronic inflammation, chronic wounds, slow-healing fractures, microvascular complications of diabetes, and metastatic spread of tumors. This extended deficiency of oxygen (O2) in the tissue sets creates a microenvironment that supports inflammation and initiates cell survival paradigms. Elevating tissue carbon dioxide levels (CO2) pushes the tissue environment toward “thrive mode,” bringing increased blood flow, added O2, reduced inflammation, and enhanced angiogenesis. This review presents the science supporting the clinical benefits observed with the administration of therapeutic CO2. It also presents the current knowledge regarding the cellular and molecular mechanisms responsible for the biological effects of CO2 therapy. The most notable findings of the review include (a) CO2 activates angiogenesis not mediated by hypoxia-inducible factor 1a, (b) CO2 is strongly anti-inflammatory, (c) CO2 inhibits tumor growth and metastasis, and (d) CO2 can stimulate the same pathways as exercise and thereby, acts as a critical mediator in the biological response of skeletal muscle to tissue hypoxia.

/pdf/the-tissue-response-to-hypoxia-how-therapeutic-carbon-15buvodt.pdf

The Tissue Response to Hypoxia: How Therapeutic Carbon Dioxide Moves the Response toward Homeostasis and Away from Instability

Plasmalemmal vacuolar type H+-ATPase (pmV-ATPase) is decreased in Microvascular Coronary Endothettal Cells (MCEC) from an insulin dependent diabetic model (BBd)

Previous work from our laboratory has demonstrated that a clone of Moloney murine sarcoma virus (MoMuSV-349) inoculated intraperitoneally into newborn BALB/c mice induces multiorgan disseminated angiosarcomatous tumors. These tumors develop in two stages: sarcomatous and angiosarcomatous. The present report investigates the relationship between tumor stage development and viral replication within the target cells using the technique of in situ hybridization. A nonradioactive RNA probe (riboprobe) labeled with digoxigenin-linked uridine triphosphate (DIG-UTP) was used to detect the presence of MoMuSV-349 in frozen tissue sections. Infected and control mice were euthanized at various times post-inoculation and tissues were collected for in situ hybridization. The riboprobe hybridized to macrophages, splenic reticular cells, mesothelial cells, megakaryocytes, Kupffer cells and neoplastic (spindled and endothelial) cells in mice infected with MoMuSV-349. The riboprobe failed to hybridize to any tissues in the non-infected mice. Cells hybridizing with the riboprobe were detected as early as 3 days post-inoculation. As the neoplasms progressed from the sarcomatous to angiosarcomatous type there was a shift in cellular target hybridized by the riboprobe from spindled cells to endothelial cells. Positive labeling of endothelial cells during the angiosarcomatous stage of tumor development suggests-that viral replication correlates with cellular proliferation. This demonstrates that in situ hybridization utilizing a non-radioactive riboprobe was useful for a pathogenesis study involving MoMuSV-349.

Relationship between Moloney murine sarcoma-virus tissue tropism and tumor-development.

Mechanisms for dietary regulation of nitric oxide synthesis in mammals.

Glucagon-like Peptide-1 Enhances Nitric Oxide Production by Coronary Endothelial Cells and improves Endothelium-dependent Coronary Microvascular Function after Cardiac Arrest and Resuscitation

Cynthia J. Meininger

Papers

The Tissue Response to Hypoxia: How Therapeutic Carbon Dioxide Moves the Response toward Homeostasis and Away from Instability

Plasmalemmal vacuolar type H+-ATPase (pmV-ATPase) is decreased in Microvascular Coronary Endothettal Cells (MCEC) from an insulin dependent diabetic model (BBd)

Relationship between Moloney murine sarcoma-virus tissue tropism and tumor-development.

Mechanisms for dietary regulation of nitric oxide synthesis in mammals.

Glucagon-like Peptide-1 Enhances Nitric Oxide Production by Coronary Endothelial Cells and improves Endothelium-dependent Coronary Microvascular Function after Cardiac Arrest and Resuscitation