Publications by authors named "Arturo Bravo-Nuevo"

The pathogenesis of Inflammatory Bowel Disease (IBD) involves complex mechanisms, including immune dysregulation, gut microbiota imbalances, oxidative stress, and defects in the gastrointestinal mucosal barrier. Current treatments for IBD often have significant limitations and adverse side effects, prompting a search for alternative therapeutic strategies. Natural products with anti-inflammatory and antioxidant properties have demonstrated potential for IBD management.

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Cholesterol accumulation in macrophages leads to the formation of foam cells and increases the risk of developing atherosclerosis. We have verified whether hydroxytyrosol (HT), a phenolic compound with anti-inflammatory and antioxidant properties, can reduce the cholesterol build up in THP-1 macrophage-derived foam cells. We have also investigated the potential mechanisms.

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Purpose: Myo/Nog cells are the source of myofibroblasts in the lens and synthesize muscle proteins in human epiretinal membranes (ERMs). In the current study, we examined the response of Myo/Nog cells during ERM formation in a mouse model of proliferative vitreoretinopathy (PVR).

Methods: PVR was induced by intravitreal injections of gas and ARPE-19 cells.

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Focal brain injury in the form of a needlestick (NS) results in cell death and induces a self-protective response flanking the lesion. Myo/Nog cells are identified by their expression of bone morphogenetic protein inhibitor Noggin, brain-specific angiogenesis inhibitor 1 (BAI1) and the skeletal muscle specific transcription factor MyoD. Myo/Nog cells limit cell death in two forms of retinopathy.

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Myo/Nog cells were discovered in the chick embryo epiblast. Their expression of MyoD reflects a commitment to the skeletal muscle lineage and capacity to differentiate into myofibroblasts. Release of Noggin by Myo/Nog cells is essential for normal morphogenesis.

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The Myo/Nog cell lineage was discovered in the chick embryo and is also present in adult mammalian tissues. The cells are named for their expression of mRNA for the skeletal muscle specific transcription factor MyoD and bone morphogenetic protein inhibitor Noggin. A third marker for Myo/Nog cells is the cell surface molecule recognized by the G8 monoclonal antibody (mAb).

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Proliferative vitreoretinopathy (PVR) is a complication of rhegmatogenous retinal detachment and ocular trauma. The disease is characterized by development of membranes that may apply traction to the retina and cause redetachment. Membrane contractions are attributed to myofibroblasts arising from retinal pigment epithelial cells, glia and fibroblasts.

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Purpose: Posterior capsule opacification (PCO) is a vision-impairing disease that occurs in some adults and most children after cataract surgery. Contractile myofibroblasts contribute to PCO by producing wrinkles in the lens capsule that scatter light. Myofibroblasts in the lens originate from Myo/Nog cells named for their expression of the MyoD transcription factor and bone morphogenetic protein inhibitor noggin.

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Meglumine is a methylamino derivative of sorbitol that is an approved drug excipient. Recent preclinical studies suggest that administration of high-dose oral meglumine can exert beneficial medicinal effects to treat diabetes, obesity, and fatty liver disease (NAFLD/nonalcoholic steatohepatitis [NASH]). Here we address gaps in knowledge about the pharmacology and toxicology of this substance administered at high concentrations to explore its medicinal potential.

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This review brings together observations on the stress-induced regulation of resilience mechanisms in body tissues. It is argued that the stresses that induce tissue resilience in mammals arise from everyday sources: sunlight, food, lack of food, hypoxia and physical stresses. At low levels, these stresses induce an organised protective response in probably all tissues; and, at some higher level, cause tissue destruction.

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Neovascularization in cancer or retinopathy is driven by pathological changes that foster abnormal sprouting of endothelial cells. Mouse genetic studies indicate that the stress-induced small GTPase RhoB is dispensable for normal physiology but required for pathogenic angiogenesis. In diabetic retinopathy, retinopathy of prematurity (ROP) or age-related wet macular degeneration (AMD), progressive pathologic anatomic changes and ischemia foster neovascularization are characterized by abnormal sprouting of endothelial cells.

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The primary energy substrate of the lens is glucose and uptake of glucose from the aqueous humor is dependent on glucose transporters. GLUT1, the facilitated glucose transporter encoded by Slc2a1 is expressed in the epithelium of bovine, human and rat lenses. In the current study, we examined the expression of GLUT1 in the mouse lens and determined its role in maintaining lens transparency by studying effects of postnatal deletion of Slc2a1.

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Myo/Nog cells, named for their expression of MyoD and noggin, enter the eye during early stages of embryonic development. Their release of noggin is critical for normal morphogenesis of the lens and retina. Myo/Nog cells are also present in adult eyes.

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Purpose: To identify Myo/Nog cells in the adult retina and test their role in protecting retinal photoreceptors from light damage.

Methods: Light damage was induced by exposing albino rats raised in dim cyclic light to 1000 lux light for 24 hours. In one group of rats, Myo/Nog cells were purified from rat brain tissue by magnetic cell sorting following binding of the G8 monoclonal antibody (mAb).

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The immune tolerogenic effects of IDO1 (indoleamine 2,3-dioxygenase 1) have been well documented and genetic studies in mice have clearly established the significance of IDO1 in tumor promotion. Dichotomously, the primary inducer of IDO1, the inflammatory cytokine IFNγ (interferon-γ), is a key mediator of immune-based tumor suppression. One means by which IFNγ can exert an anti-cancer effect is by decreasing tumor neovascularization.

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Myo/Nog cells are essential for eye development in the chick embryo and respond to injury in adult tissues. These cells express mRNA for the skeletal muscle specific transcription factor MyoD, the bone morphogenetic protein (BMP) inhibitor Noggin and the cell surface protein recognized by the G8 monoclonal antibody (mAb). In this study, we determined that Myo/Nog cells are present in low numbers in the retina of the mouse eye.

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Posterior capsule opacification (PCO) is a vision impairing condition that arises in some patients following cataract surgery. The fibrotic form of PCO is caused by myofibroblasts that may emerge in the lens years after surgery. In the chick embryo lens, myofibroblasts are derived from Myo/Nog cells that are identified by their expression of the skeletal muscle specific transcription factor MyoD, the bone morphogenetic protein inhibitor Noggin, and the epitope recognized by the G8 monoclonal antibody.

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Metabolic syndrome, diabetes and diabetes complications pose a growing medical challenge worldwide, accentuating the need of safe and effective strategies for their clinical management. Here we present preclinical evidence that the sorbitol derivative meglumine (N-methyl-D-glucamine) can safely protect against several features of metabolic syndrome and diabetes, as well as elicit enhancement in muscle stamina. Meglumine is a compound routinely used as an approved excipient to improve drug absorption that has not been ascribed any direct biological effects in vivo.

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Tumors are composed of cancer cells but also a larger number of diverse stromal cells in the tumor microenvironment. Stromal cells provide essential supports to tumor pathophysiology but the distinct characteristics of their signaling networks are not usually considered in developing drugs to target tumors. This oversight potentially confounds proof-of-concept studies and increases drug development risks.

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RhoB, a member of the Rho subfamily of small GTPases, mediates diverse cellular functions, including cytoskeletal organization, cell transformation and vesicle trafficking. The thymus undergoes progressive decline in its structure and function after puberty. We found that RhoB was expressed in thymic medullary epithelium.

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RhoB is an early-response gene whose expression is elevated by multiple cellular stresses; this gene plays an important role in cancer, macrophage motility, and apoptosis. These factors are essential for the onset of type 1 diabetes mellitus and related complications. This study explores the role of RhoB in β-cell depletion and hyperglycemia-associated complications and tests whether the pleiotropic effect of statins on glycemic control is RhoB dependent.

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In this study, we used Real-Time PCR to study the correlation of mtDNA deletions and photoreceptor death by apoptosis in one normal (SD) and two different degenerative (RCS and P23H) rat strains. Our results show that, in the SD and RCS strains, mtDNA deletion frequency increased and fell during neonatal life, correlating with rates of photoreceptor death during the critical period of photoreceptor development, and into adulthood. Results suggest that mitochondrial damage occurs in close association with photoreceptor death, in the normal (SD) and fast degenerative (RCS) retinas.

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Purpose: To assess the vulnerability of retinal photoreceptors in the BALB/cJ, C57BL/6J, and C57BL/6-c2J (c2J) mouse strains to hypoxic and hyperoxic stress.

Methods: Mice were raised in dim cyclic light. Pups aged postnatal day 7 (P7) were exposed to hypoxia (11-12% oxygen) for periods up to 23 days.

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Photoreceptor death by apoptosis is the central pathology of most forms of retinal degeneration. Mitochondria play key roles in apoptosis, releasing both signals which induce apoptosis (cytochrome c, caspases) and signals which inhibit apoptosis (Bcl-2). Because mitochondria are the site of oxidative metabolism they are also a major site of formation of the toxic oxygen intermediates which form as oxygen is recruited into the oxidative phosphorylation pathway.

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Purpose: The C57BL/6-c(2J) (c2J) mouse strain has been shown in earlier studies to be highly resistant to light damage. Subsequent studies related this resistance to an amino acid substitution (leu450met) in a pigment epithelial enzyme (RPE65), which slowed the rate of rhodopsin regeneration. The present study was conducted to examine patterns of photoreceptor death, electrophysiological function (the ERG) and trophic factor expression over the life of the C57BL/6-c(2J) retina.

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