Regulation of fibroblast growth factor-2 expression in pulmonary arterial smooth muscle cells involves increased reactive oxygen species generation

Ultrasonic Coating of Poly(D,L-lactic acid)/Poly(lactic-co-glycolic acid) Electrospun Fibers with ZnO Nanoparticles to Increase Angiogenesis in the CAM Assay

Critical-size bone defects necessitate bone void fillers that should be integrated well and be easily vascularized. One viable option is to use a biocompatible synthetic polymer and sonocoat it with zinc oxide (ZnO) nanoparticles (NPs). However, the ideal NP concentration and size must be assessed because a high dose of ZnO NPs may be toxic. Electrospun PDLLA/PLGA scaffolds were produced with different concentrations (0.5 or 1.0 s of sonocoating) and sizes of ZnO NPs (25 nm and 70 nm). They were characterized by SEM, EDX, ICP-OES, and the water contact angle. Vascularization and integration into the surrounding tissue were assessed with the CAM assay in the living chicken embryo. SEM, EDX, and ICP-OES confirmed the presence of ZnO NPs on polymer fibers. Sonocoated ZnO NPs lowered the WCA compared with the control. Smaller NPs were more pro-angiogenic exhibiting a higher vessel density than the larger NPs. At a lower concentration, less but larger vessels were visible in an environment with a lower cell density. Hence, the favored combination of smaller ZnO NPs at a lower concentration sonocoated on PDLLA/PLGA electrospun meshes leads to an advanced state of tissue integration and vascularization, providing a valuable synthetic bone graft to be used in clinics in the future.

Impact of Nintedanib and Anti-Angiogenic Agents on Uveal Melanoma Cell Behavior

Purpose

The purpose of this study was to investigate the direct impact of the combined angiokinase inhibitor nintedanib as well as the anti-angiogenic agents ranibizumab, bevacizumab, and aflibercept on the primary uveal melanoma (UM) cell line Mel270 and liver metastasis UM cell line OMM2.5.

Methods

The metabolic activity, viability, and oxidative stress levels were analyzed by the Thiazolyl Blue Tetrazolium Bromide (MTT), LIVE/DEAD, and reactive oxygen species (ROS) assays. Expression of intracellular VEGF-A165 and VEGF receptor-2 was detected by immunofluorescent staining. The secretion of VEGF-A165 into the cell culture supernatants was evaluated by VEGF-A165 ELISA.

Results

Nintedanib, at a concentration of 1 µg/mL, resulted in a median reduction of metabolic activity (for Mel270 of approximately 38% and for OMM2.5 of 46% compared to the untreated control) without exerting toxicity in either cell line, whereas the other 3 substances did not result in any changes (which also means that none of the 4 substances led to an increased cell death). Moreover, nintedanib (1 µg/mL) induced oxidative stress in the Mel270 by approximately 1.2 to 1.5-fold compared to the untreated control, but not the OMM2.5 cells.

Conclusions

Nintedanib could suppress the growth of UM cells in a concentration-dependent manner. The metastatic UM cell line OMM2.5 was not sensitive to the pro-oxidant activity of nintedanib. This study was the first to investigate nintedanib in the context of UM. We propose further investigation of this substance to elucidate its effects on this tumor entity with the hope of identifying advantageous therapeutic options for future adjuvant tumor therapies.

Advances in the study of traditional Chinese medicine affecting bone metabolism through modulation of oxidative stress

Bone metabolic homeostasis is dependent on coupled bone formation dominated by osteoblasts and bone resorption dominated by osteoclasts, which is a process of dynamic balance between bone formation and bone resorption. Notably, the formation of bone relies on the development of bone vasculature. Previous studies have shown that oxidative stress caused by disturbances in the antioxidant system of the whole organism is an important factor affecting bone metabolism. The increase in intracellular reactive oxygen species can lead to disturbances in bone metabolism, which can initiate multiple bone diseases, such as osteoporosis and osteoarthritis. Traditional Chinese medicine is considered to be an effective antioxidant. Cumulative evidence shows that the traditional Chinese medicine can alleviate oxidative stress-mediated bone metabolic disorders by modulating multiple signaling pathways, such as Nrf2/HO-1 signaling, PI3K/Akt signaling, Wnt/β-catenin signaling, NF-κB signaling, and MAPK signaling. In this paper, the potential mechanisms of traditional Chinese medicine to regulate bone me-tabolism through oxidative stress is summarized to provide direction and theoretical basis for future research related to the treatment of bone diseases with traditional Chinese medicine.

Organization of self-advantageous niche by neural stem/progenitor cells during development via autocrine VEGF-A under hypoxia

BACKGROUND

Tissue stem cells are confined within a special microenvironment called niche. Stem cells in such a niche are supplied with nutrients and contacted by other cells to maintain their characters and also to keep or expand their population size. Besides, oxygen concentration is a key factor for stem cell niche. Adult neural stem/progenitor cells (NSPCs) are known to reside in a hypoxic niche. Oxygen concentration levels are lower in fetal organs including brain than maternal organs. However, how fetal NSPCs adapt to the hypoxic environment during brain development, particularly before pial and periventricular vessels start to invade the telencephalon, has not fully been elucidated.

METHODS

NSPCs were prepared from cerebral cortices of embryonic day (E) 11.5 or E14.5 mouse embryos and were enriched by 4-day incubation with FGF2. To evaluate NSPC numbers, neurosphere formation assay was performed. Sparsely plated NSPCs were cultured to form neurospheres under the hypoxic (1% O₂) or normoxic condition. VEGF-A secreted from NSPCs in the culture medium was measured by ELISA. VEGF-A expression and Hif-1a in the developing brain was investigated by in situ hybridization and immunohistochemistry.

RESULTS

Here we show that neurosphere formation of embryonic NSPCs is dramatically increased under hypoxia compared to normoxia. Vegf-A gene expression and its protein secretion were both up-regulated in the NSPCs under hypoxia. Either recombinant VEGF-A or conditioned medium of the hypoxic NSPC culture enhanced the neurosphere forming ability of normoxic NSPCs, which was attenuated by a VEGF-A signaling inhibitor. Furthermore, in the developing brain, VEGF-A was strongly expressed in the VZ where NSPCs are confined.

CONCLUSIONS

We show that NSPCs secret VEGF-A in an autocrine fashion to efficiently maintain themselves under hypoxic developmental environment. Our results suggest that NSPCs have adaptive potential to respond to hypoxia to organize self-advantageous niche involving VEGF-A when the vascular system is immature.

Understanding Reactive Oxygen Species in Bone Regeneration: A Glance at Potential Therapeutics and Bioengineering Applications

Although the complex mechanism by which skeletal tissue heals has been well described, the role of reactive oxygen species (ROS) in skeletal tissue regeneration is less understood. It has been widely recognized that a high level of ROS is cytotoxic and inhibits normal cellular processes. However, with more recent discoveries, it is evident that ROS also play an important, positive role in skeletal tissue repair, specifically fracture healing. Thus, dampening ROS levels can potentially inhibit normal healing. On the same note, pathologically high levels of ROS cause a sharp decline in osteogenesis and promote nonunion in fracture repair. This delicate balance complicates the efforts of therapeutic and engineering approaches that aim to modulate ROS for improved tissue healing. The physiologic role of ROS is dependent on a multitude of factors, and it is important for future efforts to consider these complexities. This review first discusses how ROS influences vital signaling pathways involved in the fracture healing response, including how they affect angiogenesis and osteogenic differentiation. The latter half glances at the current approaches to control ROS for improved skeletal tissue healing, including medicinal approaches, cellular engineering, and enhanced tissue scaffolds. This review aims to provide a nuanced view of the effects of ROS on bone fracture healing which will inspire novel techniques to optimize the redox environment for skeletal tissue regeneration.

Effects of FW2 Nanoparticles Toxicity in a New In Vitro Pulmonary Vascular Cells Model Mimicking Endothelial Dysfunction

Several epidemiological studies have revealed the involvement of nanoparticles (NPs) in respiratory and cardiovascular mortality. In this work, the focus will be on the effect of manufactured carbon black NPs for risk assessment of consumers and workers, as human exposure is likely to increase. Since the pulmonary circulation could be one of the primary targets of inhaled NPs, patients suffering from pulmonary hypertension (PH) could be a population at risk. To compare the toxic effect of carbon black NPs in the pulmonary circulation under physiologic and pathological conditions, we developed a new in vitro model mimicking the endothelial dysfunction and vascular dynamics observed in vascular pathology such as PH. Human pulmonary artery endothelial cells were cultured under physiological conditions (static and normoxia 21% O₂) or under pathological conditions (20% cycle stretch and hypoxia 1% O₂). Then, cells were treated for 4 or 6 h with carbon black FW2 NPs from 5 to 10 µg/cm². Different endpoints were studied: (i) NPs internalization by transmission electronic microscopy; (ii) oxidative stress by CM-H₂DCFDA probe and electron paramagnetic resonance; (iii) NO (nitrites and nitrates) production by Griess reaction; (iv) inflammation by ELISA assay; and (v) calcium signaling by confocal microscopy. The present study characterizes the in vitro model mimicking endothelial dysfunction in PH and indicates that, under such pathological conditions, oxidative stress and inflammation are increased along with calcium signaling alterations, as compared to the physiological conditions. Human exposure to carbon black NPs could produce greater deleterious effects in vulnerable patients suffering from cardiovascular diseases.

Novel Experimental Therapies for Treatment of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a progressive and devastating disease characterized by pulmonary artery vasoconstriction and vascular remodeling leading to vascular rarefaction with elevation of pulmonary arterial pressures and pulmonary vascular resistance. Often PAH will cause death from right heart failure. Current PAH-targeted therapies improve functional capacity, pulmonary hemodynamics and reduce hospitalization. Nevertheless, today PAH still remains incurable and is often refractory to medical therapy, underscoring the need for further research. Over the last three decades, PAH has evolved from a disease of unknown pathogenesis devoid of effective therapy to a condition whose cellular, genetic and molecular underpinnings are unfolding. This article provides an update on current knowledge and summarizes the progression in recent advances in pharmacological therapy in PAH.

New Insights into the Implication of Mitochondrial Dysfunction in Tissue, Peripheral Blood Mononuclear Cells, and Platelets during Lung Diseases

Lung diseases such as chronic obstructive pulmonary disease, asthma, pulmonary arterial hypertension, or idiopathic pulmonary fibrosis are major causes of morbidity and mortality. Complex, their physiopathology is multifactorial and includes lung mitochondrial dysfunction and enhanced reactive oxygen species (ROS) release, which deserves increased attention. Further, and importantly, circulating blood cells (peripheral blood mononuclear cells-(PBMCs) and platelets) likely participate in these systemic diseases. This review presents the data published so far and shows that circulating blood cells mitochondrial oxidative capacity are likely to be reduced in chronic obstructive pulmonary disease (COPD), but enhanced in asthma and pulmonary arterial hypertension in a context of increased oxidative stress. Besides such PBMCs or platelets bioenergetics modifications, mitochondrial DNA (mtDNA) changes have also been observed in patients. These new insights open exciting challenges to determine their role as biomarkers or potential guide to a new therapeutic approach in lung diseases.

Anti-oxidative effect of the tyrosine kinase inhibitor nintedanib: a potential therapy for chronic lung allograft dysfunction?

Background: The long-term survival after lung transplantation (LTx) is often limited by the development of chronic lung allograft dysfunction (CLAD). Increased oxidative stress has been found to occur in chronic lung allograft dysfunction because of several risk factors, e.g. immunological factors or drug related factors. The aim of this study was to investigate the anti-oxidative effect of the receptor tyrosine kinase (RTK) inhibitor nintedanib on immunologically induced oxidative stress and on drug induced oxidative stress.Methods: In-vivo studies were used for investigation of immunologically induced oxidative stress: Immunohistochemistry of transglutaminase-2 (TGM-2) was used to figure out a potential anti-oxidative effect of receptor tyrosine kinase inhibitor nintedanib in a rat model of allogeneic left LTx. In-vitro studies were used for investigation of drug induced oxidative stress: Cell viability assay, 2'7'-dichlorodihydrofluorescein diacetate (DCFDA) and immunofluorescence of transglutaminase-2 were disposed to examine the potential impact of nintedanib on cyclosporin A (CsA) treated lung fibroblasts of the rat.Results: In-vivo studies: Allogeneic transplanted animals without drug interaction showed severe chronic rejection and an excessive expression of TGM-2, whereas the application of nintedanib significantly decreased the number of TGM-2 positive cells. In-vitro studies: Concentrations of CsA ranging from 250 ng/ml to 500 ng/ml demonstrated oxidative stress caused by an increased production of reactive oxygen species (ROS) and an overexpression of TGM-2 without inducing apoptosis in cells. Concentrations of more than 1000 ng/ml led to a considerable decrease of cellularity. 30 min-pre-incubation with nintedanib at a concentration between 25 and 100 nM reduced generation of intracellular ROS and expression of TGM-2.Conclusion: These results demonstrate a downregulation of ROS and TGM-2 by pretreatment with the receptor tyrosine kinase inhibitor nintedanib and present its potential anti-oxidative and immunomodulatory effect in the treatment of chronic lung allograft dysfunction.

Thiol-Redox Regulation in Lung Development and Vascular Remodeling

Significance: Redox homeostasis is finely tuned and governed by distinct intracellular mechanisms. The dysregulation of this either by external or internal events is a fundamental pathophysiologic base for many pulmonary diseases. Recent Advances: Based on recent discoveries, it is increasingly clear that cellular redox state and oxidation of signaling molecules are critical modulators of lung disease and represent a final common pathway that leads to poor respiratory outcomes. Critical Issues: Based on the wide variety of stimuli that alter specific redox signaling pathways, improved understanding of the disease and patient-specific alterations are needed for the development of therapeutic targets. Further Directions: For the full comprehension of redox signaling in pulmonary disease, it is essential to recognize the role of reactive oxygen intermediates in modulating biological responses. This review summarizes current knowledge of redox signaling in pulmonary development and pulmonary vascular disease.

VEGF and FGF-2: Promising targets for the treatment of respiratory disorders

The endothelial cells play a crucial role in the progression of angiogenesis, which causes cell re-modulation, proliferation, adhesion, migration, invasion and survival. Angiogenic factors like cytokines, cell adhesion molecules, growth factors, vasoactive peptides, proteolytic enzymes (metalloproteinases) and plasminogen activators bind to their receptors on endothelial cells and activate the signal transduction pathways like epidermal growth factor receptor (EGFR phosphatidylinositol 3-kinase and (PI3K)/AKT/mammalian target of rapamycin (mTOR) which initiate the process of angiogenesis. Cytokines that stimulate angiogenesis include direct and indirect proangiogenic markers. The direct proangiogenic group of markers consists of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF-2) and hepatocyte growth factor (HGF) whereas the indirect proangiogenic markers include transforming growth factor-beta (TGF-β), interleukin 6 (IL-6), interleukin 8 (IL-8) and platelet-derived growth factor (PDGF). VEGF and FGF-2 are the strongest activators of angiogenesis which stimulate migration and proliferation of endothelial cells in existing vessels to generate and stabilize new blood vessels. VEGF is released in hypoxic conditions as an effect of the hypoxia-inducible factor (HIF-1α) and causes re-modulation and inflammation of bronchi cell. Cell re-modulation and inflammation leads to the development of various lung disorders like pulmonary hypertension, chronic obstructive pulmonary disease, asthma, fibrosis and lung cancer. This indicates that there is a firm link between overexpression of VEGF and FGF-2 with lung disorders. Various natural and synthetic drugs are available for reducing the overexpression of VEGF and FGF-2 which can be helpful in treating lung disorders. Researchers are still searching for new angiogenic inhibitors which can be helpful in the treatment of lung disorders. The present review emphasizes on molecular mechanisms and new drug discovery focused on VEGF and FGF-2 inhibitors and their role as anti-angiogenetic agents in lung disorders.

Skeletal muscle insulin resistance: role of mitochondria and other ROS sources

At present, obesity is one of the most important public health problems in the world because it causes several diseases and reduces life expectancy. Although it is well known that insulin resistance plays a pivotal role in the development of type 2 diabetes mellitus (the more frequent disease in obese people) the link between obesity and insulin resistance is yet a matter of debate. One of the most deleterious effects of obesity is the deposition of lipids in non-adipose tissues when the capacity of adipose tissue is overwhelmed. During the last decade, reduced mitochondrial function has been considered as an important contributor to 'toxic' lipid metabolite accumulation and consequent insulin resistance. More recent reports suggest that mitochondrial dysfunction is not an early event in the development of insulin resistance, but rather a complication of the hyperlipidemia-induced reactive oxygen species (ROS) production in skeletal muscle, which might promote mitochondrial alterations, lipid accumulation and inhibition of insulin action. Here, we review the literature dealing with the mitochondria-centered mechanisms proposed to explain the onset of obesity-linked IR in skeletal muscle. We conclude that the different pathways leading to insulin resistance may act synergistically because ROS production by mitochondria and other sources can result in mitochondrial dysfunction, which in turn can further increase ROS production leading to the establishment of a harmful positive feedback loop.

Controlled Delivery of Extracellular ROS Based on Hematoporphyrin-Incorporated Polyurethane Film for Enhanced Proliferation of Endothelial Cells

The principle of photodynamic treatment (PDT) involves the administration of photosensitizer (PS) at diseased tissues, followed by light irradiation to produce reactive oxygen species (ROS). In cells, a moderate increase in ROS plays an important role as signaling molecule to promote cell proliferation, whereas a severe increase of ROS causes cell damage. Previous studies have shown that low levels of ROS stimulate cell growth through PS drugs-treating PDT and nonthermal plasma treatment. However, these methods have side effects which are associated with low tissue selectivity and remaining of PS residues. To overcome such shortcomings, we designed hematoporphyrin-incorporated polyurethane (PU) film induced generation of extracellular ROS with singlet oxygen and free radicals. The film can easily control ROS production rate by regulating several parameters including light dose, PS dose. Also, its use facilitates targeted delivery of ROS to the specific lesion. Our study demonstrated that extracellular ROS could induce the formation of intracellular ROS. In vascular endothelial cells, a moderated increase in intracellular ROS also stimulated cell proliferation and cell cycle progression by accurate control of optimum levels of ROS with hematoporphyrin-incorporated polymer films. This modulation of cellular growth is expected to be an effective strategy for the design of next-generation PDT.

Adverse Outcome Pathways for Regulatory Applications: Examination of Four Case Studies With Different Degrees of Completeness and Scientific Confidence

Adverse outcome pathways (AOPs) offer a pathway-based toxicological framework to support hazard assessment and regulatory decision-making. However, little has been discussed about the scientific confidence needed, or how complete a pathway should be, before use in a specific regulatory application. Here we review four case studies to explore the degree of scientific confidence and extent of completeness (in terms of causal events) that is required for an AOP to be useful for a specific purpose in a regulatory application: (i) Membrane disruption (Narcosis) leading to respiratory failure (low confidence), (ii) Hepatocellular proliferation leading to cancer (partial pathway, moderate confidence), (iii) Covalent binding to proteins leading to skin sensitization (high confidence), and (iv) Aromatase inhibition leading to reproductive dysfunction in fish (high confidence). Partially complete AOPs with unknown molecular initiating events, such as 'Hepatocellular proliferation leading to cancer', were found to be valuable. We demonstrate that scientific confidence in these pathways can be increased though the use of unconventional information (eg, computational identification of potential initiators). AOPs at all levels of confidence can contribute to specific uses. A significant statistical or quantitative relationship between events and/or the adverse outcome relationships is a common characteristic of AOPs, both incomplete and complete, that have specific regulatory uses. For AOPs to be useful in a regulatory context they must be at least as useful as the tools that regulators currently possess, or the techniques currently employed by regulators.

DNA Damage and Pulmonary Hypertension

Pulmonary hypertension (PH) is defined by a mean pulmonary arterial pressure over 25 mmHg at rest and is diagnosed by right heart catheterization. Among the different groups of PH, pulmonary arterial hypertension (PAH) is characterized by a progressive obstruction of distal pulmonary arteries, related to endothelial cell dysfunction and vascular cell proliferation, which leads to an increased pulmonary vascular resistance, right ventricular hypertrophy, and right heart failure. Although the primary trigger of PAH remains unknown, oxidative stress and inflammation have been shown to play a key role in the development and progression of vascular remodeling. These factors are known to increase DNA damage that might favor the emergence of the proliferative and apoptosis-resistant phenotype observed in PAH vascular cells. High levels of DNA damage were reported to occur in PAH lungs and remodeled arteries as well as in animal models of PH. Moreover, recent studies have demonstrated that impaired DNA-response mechanisms may lead to an increased mutagen sensitivity in PAH patients. Finally, PAH was linked with decreased breast cancer 1 protein (BRCA1) and DNA topoisomerase 2-binding protein 1 (TopBP1) expression, both involved in maintaining genome integrity. This review aims to provide an overview of recent evidence of DNA damage and DNA repair deficiency and their implication in PAH pathogenesis.

Stem Cells in Skin Wound Healing: Are We There Yet?

Significance: Cutaneous wound healing is a serious problem worldwide that affects patients with various wound types, resulting from burns, traumatic injuries, and diabetes. Despite the wide range of clinically available skin substitutes and the different therapeutic alternatives, delayed healing and scarring are often observed. Recent Advances: Stem cells have arisen as powerful tools to improve skin wound healing, due to features such as effective secretome, self-renewal, low immunogenicity, and differentiation capacity. They represent potentially readily available biological material that can particularly target distinct wound-healing phases. In this context, mesenchymal stem cells have been shown to promote cell migration, angiogenesis, and a possible regenerative rather than fibrotic microenvironment at the wound site, mainly through paracrine signaling with the surrounding cells/tissues. Critical Issues: Despite the current insights, there are still major hurdles to be overcome to achieve effective therapeutic effects. Limited engraftment and survival at the wound site are still major concerns, and alternative approaches to maximize stem cell potential are a major demand. Future Directions: This review emphasizes two main strategies that have been explored in this context. These comprise the exploration of hypoxic conditions to modulate stem cell secretome, and the use of adipose tissue stromal vascular fraction as a source of multiple cells, including stem cells and factors requiring minimal manipulation. Nonetheless, the attainment of these approaches to target successfully skin regeneration will be only evident after a significant number of in vivo works in relevant pre-clinical models.

Characteristics of Skeletal Muscle Fibers of SOD1 Knockout Mice

Cu/Zn superoxide dismutase (SOD1) knockout (KO) mice are known as an aging model in some aspects, but the damage and regeneration process of each fiber type have not been sufficiently studied. In this study, we investigated the damage and satellite cell state of the gastrocnemius muscle in SOD1 KO mice (6 months old) using immunohistochemical staining and real-time RT-PCR. The proportion of central nuclei-containing Type IIx/b fibers in the deep and superficial portions of the gastrocnemius muscle was significantly higher in SOD1 KO than control mice. The number of satellite cells per muscle fiber decreased in all muscle fiber types in the deep portion of the gastrocnemius muscle in SOD1 KO mice. In addition, the mRNA expression levels of Pax7 and myogenin, which are expressed in satellite cells in the activation, proliferation, and differentiation states, significantly increased in the gastrocnemius muscle of SOD1 KO mice. Furthermore, mRNA of myosin heavy chain-embryonic, which is expressed in the early phase of muscle regeneration, significantly increased in SOD1 KO mice. It was suggested that muscle is damaged by reactive oxygen species produced in the mitochondrial intermembrane space in Type IIxb fibers, accelerating the proliferation and differentiation of satellite cells through growth factors in SOD1 KO mice.

Deferoxamine preconditioning to restore impaired HIF-1α-mediated angiogenic mechanisms in adipose-derived stem cells from STZ-induced type 1 diabetic rats

OBJECTIVES

Both excessive and insufficient angiogenesis are associated with progression of diabetic complications, of which poor angiogenesis is an important feature. Currently, adipose-derived stem cells (ADSCs) are considered to be a promising source to aid therapeutic neovascularization. However, functionality of these cells is impaired by diabetes which can result from a defect in hypoxia-inducible factor-1 (HIF-1), a key mediator involved in neovascularization. In the current study, we sought to explore effectiveness of pharmacological priming with deferoxamine (DFO) as a hypoxia mimetic agent, to restore the compromised angiogenic pathway, with the aid of ADSCs derived from streptozotocin (STZ)-induced type 1 diabetic rats ('diabetic ADSCs').

MATERIALS AND METHODS

Diabetic ADSCs were treated with DFO and compared to normal and non-treated diabetic ADSCs for expression of HIF-1α, VEGF, FGF-2 and SDF-1, at mRNA and protein levels, using qRT-PCR, western blotting and ELISA assay. Activity of matrix metalloproteinases -2 and -9 were measured using a gelatin zymography assay. Angiogenic potential of conditioned media derived from normal, DFO-treated and non-treated diabetic ADSCs were determined by in vitro (in HUVECs) and in vivo experiments including scratch assay, three-dimensional tube formation testing and surgical wound healing models.

RESULTS

DFO remarkably enhanced expression of noted genes by mRNA and protein levels and restored activity of matrix metalloproteinases -2 and -9. Compromised angiogenic potential of conditioned medium derived from diabetic ADSCs was restored by DFO both in vitro and in vivo experiments.

CONCLUSION

DFO preconditioning restored neovascularization potential of ADSCs derived from diabetic rats by affecting the HIF-1α pathway.

Stimulation of α7 nicotinic acetylcholine receptor regulates glutamate transporter GLAST via basic fibroblast growth factor production in cultured cortical microglia

The α7 nicotinic acetylcholine (nACh) receptor expressed in microglia has a crucial role in neuroprotection. Simulation of α7 nACh receptor leads to increased expression of glutamate/aspartate transporter (GLAST), which in turn decreases synaptic glutamate levels. However, the upregulation of GLAST in cultured rat cortical microglia appears long after (over 18 h) stimulation of the α7 nACh receptor with nicotine. Thus, the current study elucidated the pathway responsible for the induction of GLAST expression in cultured cortical microglia. Nicotine-induced GLAST mRNA expression was significantly inhibited by cycloheximide pretreatment, indicating that a protein intermediary, such as a growth factor, is required for GLAST expression. The expression of fibroblast growth factor-2 (FGF-2) mRNA in cortical microglia was significantly increased 6 and 12h after treatment with nicotine, and this increase was potently inhibited by pretreatment with methyllycaconitine, a selective α7 nACh receptor antagonist. The treatment with nicotine also significantly increased FGF-2 protein expression. Furthermore, treatment with recombinant FGF-2 increased GLAST mRNA, protein expression and (14)C-glutamate uptake, a functional measurement of GLAST activity. Conversely, pretreatment with PD173074, an inhibitor of FGF receptor (FGFR) tyrosine kinase, significantly prevented the nicotine-induced expression of GLAST mRNA, its protein and (14)C-glutamate uptake. Reverse transcription polymerase chain reaction confirmed FGFR1 mRNA expression was confined to cultured cortical microglia. Together, the current findings demonstrate that the neuroprotective effect of activation of microglial α7 nACh receptors could be due to the expression of FGF-2, which in turn increases GLAST expression, thereby clearing glutamate from synapse and decreasing glutamate neurotransmission.

Apocynin Attenuates Cardiac Injury in Type 4 Cardiorenal Syndrome via Suppressing Cardiac Fibroblast Growth Factor-2 With Oxidative Stress Inhibition

Background

Type 4 cardiorenal syndrome (CRS) refers to the cardiac injury induced by chronic kidney disease. We aimed to assess oxidative stress and cardiac injury in patients with type 4 CRS, determine whether the antioxidant apocynin attenuated cardiac injury in rats with type 4 CRS, and explore potential mechanisms.

Methods and Results

A cross-sectional study was conducted among patients with type 4 CRS (n=17) and controls (n=16). Compared with controls, patients with type 4 CRS showed elevated oxidative stress, which was significantly correlated with cardiac hypertrophy and decreased ejection fraction. In vivo study, male Sprague-Dawley rats underwent 5/6 subtotal nephrectomy and sham surgery, followed with apocynin or vehicle treatment for 8 weeks. Eight weeks after surgery, the 5/6 subtotal nephrectomy rats mimicked type 4 CRS, showing increased serum creatinine, cardiac hypertrophy and fibrosis, and decreased ejection fraction compared with sham-operated animals. Cardiac malondialdehyde, NADPH oxidase activity, fibroblast growth factor-2, and extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation increased significantly in the 5/6 subtotal nephrectomy rats. These changes were significantly attenuated by apocynin. In vitro study showed that apocynin reduced angiotensin II–induced NADPH oxidase–dependent oxidative stress, upregulation of fibroblast growth factor-2 and fibrosis biomarkers, and ERK1/2 phosphorylation in cardiac fibroblasts. Importantly, the ERK1/2 inhibitor U0126 reduced the upregulation of fibroblast growth factor-2 and fibrosis biomarkers in angiotensin II–treated fibroblasts.

Conclusions

Oxidative stress is a candidate mediator for type 4 CRS. Apocynin attenuated cardiac injury in type 4 CRS rats via inhibiting NADPH oxidase–dependent oxidative stress-activated ERK1/2 pathway and subsequent fibroblast growth factor-2 upregulation. Our study added evidence to the beneficial effect of apocynin in type 4 CRS.

Effects of prenatal and postnatal exposure of Wi-Fi on development of teeth and changes in teeth element concentration in rats. [corrected]

The present study determined the effects of prenatal and postnatal exposure to Wi-Fi (2.45 GHz)-induced electromagnetic radiation (EMR) on tooth and surrounding tissue development as well as the element levels in growing rats. Twenty-four rats and their offspring were equally divided into two separate groups identified as experiment and control. The experiment group was exposed to 2.45 GHz EMR for 2 h/day during the periods of pregnancy (21 days) and lactation (21 days). The offspring of these dams were also exposed to EMR up to decapitation. The control group was exposed to cage stress for 2 h per day using the same protocol established for the experimental group. On the 7th, 14th, and 21st days after birth, 8 male offspring rats from each of the two groups were decapitated, and the jaws were taken for histological and immunohistochemical examination. Caspase-3 (1/50 dilution) was used in the immunohistochemical examination for apoptotic activity. On the last day of the experiment, the rats' incisors were also collected. In samples that were histologically and immunohistochemically examined, there was an increase in apoptosis and caspase-3 in both the control and the Wi-Fi groups during the development of the teeth. However, no significant difference was observed between the two groups in terms of development and apoptotic activity. Results from the elemental analysis showed that iron and strontium concentrations were increased in the Wi-Fi group, whereas boron, copper, and zinc concentrations were decreased. There were no statistically significant differences in calcium, cadmium, potassium, magnesium, sodium, or phosphorus values between the groups. Histological and immunohistochemical examinations between the experimental and control groups showed that exposure to 2.45 GHz EMR for 2 h per day does not interfere with the development of teeth and surrounding tissues. However, there were alterations in the elemental composition of the teeth, especially affecting such oxidative stress-related elements as copper, zinc, and iron, suggesting that short-term exposure to Wi-Fi-induced EMR may cause an imbalance in the oxidative stress condition in the teeth of growing rats.

Role of reactive oxygen species in neonatal pulmonary vascular disease

SIGNIFICANCE

Abnormal lung development in the perinatal period can result in severe neonatal complications, including persistent pulmonary hypertension (PH) of the newborn and bronchopulmonary dysplasia. Reactive oxygen species (ROS) play a substantive role in the development of PH associated with these diseases. ROS impair the normal pulmonary artery (PA) relaxation in response to vasodilators, and ROS are also implicated in pulmonary arterial remodeling, both of which can increase the severity of PH.

RECENT ADVANCES

PA ROS levels are elevated when endogenous ROS-generating enzymes are activated and/or when endogenous ROS scavengers are inactivated. Animal models have provided valuable insights into ROS generators and scavengers that are dysregulated in different forms of neonatal PH, thus identifying potential therapeutic targets.

CRITICAL ISSUES

General antioxidant therapy has proved ineffective in reversing PH, suggesting that it is necessary to target specific signaling pathways for successful therapy.

FUTURE DIRECTIONS

Development of novel selective pharmacologic inhibitors along with nonantioxidant therapies may improve the treatment outcomes of patients with PH, while further investigation of the underlying mechanisms may enable earlier detection of the disease.

Glucose, insulin, and oxygen interplay in placental hypervascularisation in diabetes mellitus

The placental vasculature rapidly expands during the course of pregnancy in order to sustain the growing needs of the fetus. Angiogenesis and vascular growth are stimulated and regulated by a variety of growth factors expressed in the placenta or present in the fetal circulation. Like in tumors, hypoxia is a major regulator of angiogenesis because of its ability to stimulate expression of various proangiogenic factors. Chronic fetal hypoxia is often found in pregnancies complicated by maternal diabetes as a result of fetal hyperglycaemia and hyperinsulinemia. Both are associated with altered levels of hormones, growth factors, and proinflammatory cytokines, which may act in a proangiogenic manner and, hence, affect placental angiogenesis and vascular development. Indeed, the placenta in diabetes is characterized by hypervascularisation, demonstrating high placental plasticity in response to diabetic metabolic derangements. This review describes the major regulators of placental angiogenesis and how the diabetic environment in utero alters their expression. In the light of hypervascularized diabetic placenta, the focus was placed on proangiogenic factors.

Extracellular matrix composition is modified by β₂-agonists through cAMP in COPD

Long acting β₂-agonists (LABA) have been reported to modify the extracellular matrix (ECM) composition in the airway wall. Based on our earlier studies we here investigated the mechanism underlying the control of ECM modification by LABA in primary human airway smooth muscle cells. Cells were treated with formoterol or salmeterol (30 min) before TGF-β₁ stimulation (2-3 days) Using RT-PCT, immuno-blotting and ELISA the de novo synthesis and deposition of collagen type-I, -III, -IV and fibronectin were determined. Matrix metalloproteinases (MMP)-2 and -9 were analyzed by zymography. Both LABA activated cAMP and its corresponding transcription factor CREB within 60 min and thus partly reduced TGF-β₁-induced gene transcription of collagen type-I, -III, fibronectin and connective tissue growth factor (CTGF). The inhibitory effect of both LABA on collagen type-I and -III deposition involved a cAMP dependent mechanism, while the inhibitory effect of the two drugs on TGF-β1-induced fibronectin deposition and on CTGF secretion was independent of cAMP. Interestingly, none of the two LABA reduced CTGF-induced synthesis of collagen type-I or type-III deposition. In addition, none of the two LABA modified collagen type-IV deposition or the expression and activity of MMP-2 or MMP-9. Our results show that LABA can prevent de novo deposition of specific ECM components through cAMP dependent and independent signaling. However, they do not reduce all ECM components by the same mechanism and they do not reduce existing collagen deposits. This might explain some of the controversial reports on the anti-remodeling effect of LABA in chronic inflammatory lung diseases.

Obstetric conditions and the placental weight ratio

INTRODUCTION

To elucidate how obstetric conditions are associated with atypical placental weight ratios (PWR)s in infants born: (a) ≥37 weeks gestation; (b) at ≥33 but <37 weeks gestation; and (c) <33 weeks gestation.

METHODS

The study included all in-hospital singleton births in London, Ontario between June 1, 2006 and March 31, 2011. PWR was assessed as <10th or >90th percentile by gestational age-specific local population standards. Multivariable analysis was carried out using multinomial logistic regression with blockwise variable entry in order of temporality.

RESULTS

Baseline factors and maternal obstetric conditions associated with PWR <10th percentile were: increasing maternal height, overweight and obese body mass indexes (BMI), large for gestational age infants, smoking, and gestational diabetes. Obstetric factors associated with PWR >90th percentile were: underweight, overweight and obese BMIs, smoking, preeclampsia, placenta previa, and placental abruption. In particular, indicators of hypoxia and altered placental function were generally associated with elevated PWR at all gestations.

DISCUSSION

An association between obstetric conditions associated with fetal hypoxia and PWR ≥90th percentile was illustrated.

CONCLUSIONS

The multivariable findings suggest that the PWR is similarly increased regardless of the etiology of the hypoxia.

Vasotrophic regulation of age-dependent hypoxic cerebrovascular remodeling

Hypoxia can induce functional and structural vascular remodeling by changing the expression of trophic factors to promote homeostasis. While most experimental approaches have been focused on functional remodeling, structural remodeling can reflect changes in the abundance and organization of vascular proteins that determine functional remodeling. Better understanding of age-dependent hypoxic macrovascular remodeling processes of the cerebral vasculature and its clinical implications require knowledge of the vasotrophic factors that influence arterial structure and function. Hypoxia can affect the expression of transcription factors, classical receptor tyrosine kinase factors, non-classical G-protein coupled factors, catecholamines, and purines. Hypoxia's remodeling effects can be mediated by Hypoxia Inducible Factor (HIF) upregulation in most vascular beds, but alterations in the expression of growth factors can also be independent of HIF. PPARγ is another transcription factor involved in hypoxic remodeling. Expression of classical receptor tyrosine kinase ligands, including vascular endothelial growth factor, platelet derived growth factor, fibroblast growth factor and angiopoietins, can be altered by hypoxia which can act simultaneously to affect remodeling. Tyrosine kinase-independent factors, such as transforming growth factor, nitric oxide, endothelin, angiotensin II, catecholamines, and purines also participate in the remodeling process. This adaptation to hypoxic stress can fundamentally change with age, resulting in different responses between fetuses and adults. Overall, these mechanisms integrate to assure that blood flow and metabolic demand are closely matched in all vascular beds and emphasize the view that the vascular wall is a highly dynamic and heterogeneous tissue with multiple cell types undergoing regular phenotypic transformation.

Reactive oxygen species in pulmonary vascular remodeling

The pathogenesis of pulmonary hypertension is a complex multifactorial process that involves the remodeling of pulmonary arteries. This remodeling process encompasses concentric medial thickening of small arterioles, neomuscularization of previously nonmuscular capillary-like vessels, and structural wall changes in larger pulmonary arteries. The pulmonary arterial muscularization is characterized by vascular smooth muscle cell hyperplasia and hypertrophy. In addition, in uncontrolled pulmonary hypertension, the clonal expansion of apoptosis-resistant endothelial cells leads to the formation of plexiform lesions. Based upon a large number of studies in animal models, the three major stimuli that drive the vascular remodeling process are inflammation, shear stress, and hypoxia. Although, the precise mechanisms by which these stimuli impair pulmonary vascular function and structure are unknown, reactive oxygen species (ROS)-mediated oxidative damage appears to play an important role. ROS are highly reactive due to their unpaired valence shell electron. Oxidative damage occurs when the production of ROS exceeds the quenching capacity of the antioxidant mechanisms of the cell. ROS can be produced from complexes in the cell membrane (nicotinamide adenine dinucleotide phosphate-oxidase), cellular organelles (peroxisomes and mitochondria), and in the cytoplasm (xanthine oxidase). Furthermore, low levels of tetrahydrobiopterin (BH4) and L-arginine the rate limiting cofactor and substrate for endothelial nitric oxide synthase (eNOS), can cause the uncoupling of eNOS, resulting in decreased NO production and increased ROS production. This review will focus on the ROS generation systems, scavenger antioxidants, and oxidative stress associated alterations in vascular remodeling in pulmonary hypertension.

Isolation of pulmonary artery smooth muscle cells from neonatal mice

Pulmonary hypertension is a significant cause of morbidity and mortality in infants. Historically, there has been significant study of the signaling pathways involved in vascular smooth muscle contraction in PASMC from fetal sheep. While sheep make an excellent model of term pulmonary hypertension, they are very expensive and lack the advantage of genetic manipulation found in mice. Conversely, the inability to isolate PASMC from mice was a significant limitation of that system. Here we described the isolation of primary cultures of mouse PASMC from P7, P14, and P21 mice using a variation of the previously described technique of Marshall et al. that was previously used to isolate rat PASMC. These murine PASMC represent a novel tool for the study of signaling pathways in the neonatal period. Briefly, a slurry of 0.5% (w/v) agarose + 0.5% iron particles in M199 media is infused into the pulmonary vascular bed via the right ventricle (RV). The iron particles are 0.2 μM in diameter and cannot pass through the pulmonary capillary bed. Thus, the iron lodges in the small pulmonary arteries (PA). The lungs are inflated with agarose, removed and dissociated. The iron-containing vessels are pulled down with a magnet. After collagenase (80 U/ml) treatment and further dissociation, the vessels are put into a tissue culture dish in M199 media containing 20% fetal bovine serum (FBS), and antibiotics (M199 complete media) to allow cell migration onto the culture dish. This initial plate of cells is a 50-50 mixture of fibroblasts and PASMC. Thus, the pull down procedure is repeated multiple times to achieve a more pure PASMC population and remove any residual iron. Smooth muscle cell identity is confirmed by immunostaining for smooth muscle myosin and desmin.

Macrophage-tumor cell interactions regulate the function of nitric oxide

Tumor cell-macrophage interactions change as the tumor progresses, and the generation of nitric oxide (NO) by the inducible nitric oxide synthase (iNOS) plays a major role in this interplay. In early stages, macrophages employ their killing mechanisms, particularly the generation of high concentrations of NO and its derivative reactive nitrogen species (RNS) to initiate tumor cell apoptosis and destroy emerging transformed cells. If the tumor escapes the immune system and grows, macrophages that infiltrate it are reprogramed in situ by the tumor microenvironment. Low oxygen tensions (hypoxia) and immunosuppressive cytokines inhibit iNOS activity and lead to production of low amounts of NO/RNS, which are pro-angiogenic and support tumor growth and metastasis by inducing growth factors (e.g., VEGF) and matrix metalloproteinases (MMPs). We review here the different roles of NO/RNS in tumor progression and inhibition, and the mechanisms that regulate iNOS expression and NO production, highlighting the role of different subtypes of macrophages and the microenvironment. We finally claim that some tumor cells may become resistant to macrophage-induced death by increasing their expression of microRNA-146a (miR-146a), which leads to inhibition of iNOS translation. This implies that some cooperation between tumor cells and macrophages is required to induce tumor cell death, and that tumor cells may control their fate. Thus, in order to induce susceptibility of tumors cells to macrophage-induced death, we suggest a new therapeutic approach that couples manipulation of miR-146a levels in tumors with macrophage therapy, which relies on ex vivo stimulation of macrophages and their re-introduction to tumors.

Joint immobilization induced hypoxic and inflammatory conditions in rat knee joints

The purpose of this study was to examine the hypoxic and inflammatory conditions after immobilization in the joint capsule of rat knees. The unilateral knee joints of adult male rats were immobilized with an internal fixator (Im group) for 1 day, 3 days, and 1, 2, 4, 8, and 16 weeks. Sham-operated animals had holes drilled in the femur and tibia and screws inserted without a plate (control group). The number of cells and blood vessels in the capsule were histologically examined. The hypoxic condition in the capsule was histologically examined with a Hypoxyprobe™-1. The gene expressions related to the hypoxic (hypoxia inducible factor-1α, vascular endothelial growth factor, and fibroblast growth factor 2) and inflammatory conditions [interleukin-6 (IL-6), IL-1α, IL-1β, tumor necrosis factor-α, and tumor necrosis factor-β] were evaluated by quantitative reverse transcription polymerase chain reaction. The number of cells was unchanged at 1 day in the two groups; however, the number significantly increased at 3 days in the Im group. The number of blood vessels in the Im group gradually decreased. Strong immunostaining of Hypoxyprobe™-1 around the blood vessels was observed in the Im group. The gene expressions of hypoxia inducible factor-1α and fibroblast growth factor 2 were significantly higher in the Im group compared with those in the control group. The gene expressions of IL-6, IL-1α, IL-1β, and tumor necrosis factor-β were significantly higher in the Im group compared with those in the control group. These data indicated that joint immobilization induced hypoxic and inflammatory conditions in the joint capsule, which might be an initiating factor for joint contracture.

Mechanical stretch changes coronary artery fibroblasts function by upregulating HSF1 protein expression

The study is designed to investigate effect of mechanical stretch on the function of fibroblast cells. Human coronary artery fibroblasts were cultured. They were divided into two groups: stretch group (stretch for 24h) and no-stretch group (did not stretch). ELISA analysis was used for detection of collagen secretion. CCK-8 method was used for detection of cells proliferation. RT-PCR method was used for detection of MMP, TIMP, IL-6, alpha-SMA, HSF1 and HSP70 mRNA expression. Western-blotting method was used for detection of HSF1 protein expression. Results showed that cells proliferation in stretch group was stronger than that in no-stretch group. Hydroxyproline secretion in stretch group was more than that in no-stretch group. MMP-9/TIMP, alpha-SMA, IL-6, HSF1 and HSP70 in stretch group was higher than those in no-stretch group. Western-blotting analysis showed that HSF1 protein expression was upregulated in stretch group. It can be concluded that mechanical stretch changed human coronary artery fibroblasts cells proliferation, collagen formation, the secretion of inflammatory factor possibly by upregulating HSF1 protein expression.

Reactive oxygen species as therapeutic targets in pulmonary hypertension

Pulmonary hypertension (PH) is characterized by a progressive elevation of pulmonary arterial pressure due to alterations of both pulmonary vascular structure and function. This disease is rare but life-threatening, leading to the development of right heart failure. Current PH treatments, designed to target altered pulmonary vascular reactivity, include vasodilating prostanoids, phosphodiesterase-5 inhibitors and endothelin-1 receptor antagonists. Although managing to slow the progression of the disease, these molecules still do not cure PH. More effective treatments need to be developed, and novel therapeutic strategies, targeting in particular vascular remodelling, are currently under investigation. Reactive oxygen species (ROS) are important physiological messengers in vascular cells. In addition to atherosclerosis and other systemic vascular diseases, emerging evidence also support a role of ROS in PH pathogenesis. ROS production is increased in animal models of PH, associated with NADPH oxidases increased expression, in particular of several Nox enzymes thought to be the major source of ROS in the pulmonary vasculature. These increases have also been observed in vitro and in vivo in humans. Moreover, several studies have shown either the deleterious effect of agents promoting ROS generation on pulmonary vasculature or, conversely, the beneficial effect of antioxidant agents in animal models of PH. In these studies, ROS production has been directly linked to pulmonary vascular remodelling, endothelial dysfunction, altered vasoconstrictive responses, inflammation and modifications of the extracellular matrix, all important features of PH pathophysiology. Altogether, these findings indicate that ROS are interesting therapeutic targets in PH. Blockade of ROS-dependent signalling pathways, or disruption of sources of ROS in the pulmonary vasculature, targeting in particular Nox enzymes, represent promising new therapeutic strategies in this disease.

Tubulocystic renal cell carcinoma: is there a rational reason for targeted therapy using angiogenic inhibition? Analysis of seven cases

Generally, patients with renal cell carcinoma (RCC) are viewed as potential candidates for antiangiogenic targeted therapy. Tubulocystic RCC (TCRC) is a recently described entity which may behave aggressively, and the rationale for antiangiogenic therapy in this group of renal tumors has yet to be determined. Seven TCRCs and five non-tumor tissue samples from seven patients were subjected to relative expression analysis of mRNA levels of 16 genes involved in three angiogenic signal pathways: (1) VHL/HIF, (2) RTK/mitogen-activated protein kinase (MAPK), and (3) PI3K/Akt/mTOR. Two of them, pathways (2) and (3), are often targeted by antiangiogenic agents. We also determined the mutation and methylation status of the VHL gene. Finally, the levels of vascular endothelial growth factor A (VEGFA), HIF-1α, HIF-2α proteins, and phosphorylated mTOR protein were also determined. The comparison of tumor and control samples revealed no changes of mRNA levels of the following genes: VHL, HIF-1α, HIF-2α, PTEN, Akt2, Akt3, mTOR, VEGFA, KDR, HRas, C-Jun, EGFR, and FGF2. Significantly elevated mRNA level of TP53 was found, while the mRNA levels of FLT1 and C-FOS were reduced in tumor samples. No mutations or methylation in the VHL gene were found. Changes in levels of studied proteins VEGFA, HIF-1α, HIF-2α, and increased phosphorylation of mTOR protein were not found. Three studied angiogenic pathways (VHL/HIF, RTK/MAPK, and PI3K/Akt/mTOR) seem not to be upregulated in TCRC samples, so there appears to be no rationale for a general recommendation of antiangiogenic targeted therapeutic protocols for patients with these tumors.

Link between the renin-angiotensin system and insulin resistance: implications for cardiovascular disease

The incidence of metabolic syndrome is rapidly increasing in the United States and worldwide. The metabolic syndrome is a complex metabolic and vascular disorder that is associated with inappropriate activation of the renin-angiotensin-aldosterone system (RAAS) in the cardiovascular (CV) system and increased CV morbidity and mortality. Insulin activation of the phosphatidylinositol-3-kinase (PI3K) pathway promotes nitric oxide (NO) production in the endothelium and glucose uptake in insulin-sensitive tissues. Angiotensin (Ang) II inhibits insulin-mediated PI3K pathway activation, thereby impairing endothelial NO production and Glut-4 translocation in insulin-sensitive tissues, which results in vascular and systemic insulin resistance, respectively. On the other hand, Ang II enhances insulin-mediated activation of the mitogen-activated protein kinase (MAPK) pathway, which leads to vasoconstriction and pathologic vascular cellular growth. Therefore, the interaction of Ang II with insulin signaling is fully operative not only in insulin-sensitive tissues but also in CV tissues, thereby linking insulin resistance and CV disease. This notion is further supported by an increasing number of experimental and clinical studies indicating that pharmacological blockade of RAAS improves insulin sensitivity and endothelial function, as well as reduces the incidence of new-onset diabetes in high-risk patients with CV disease. This article reviews experimental and clinical data elucidating the physiological and pathophysiological role of the interaction between insulin and RAAS in the development of insulin resistance as well as CV disease.

Oxidative stress and the development of endothelial dysfunction in congenital heart disease with increased pulmonary blood flow: lessons from the neonatal lamb

Congenital heart diseases associated with increased pulmonary blood flow commonly leads to the development of pulmonary hypertension. However, most patients who undergo histological evaluation have advanced pulmonary hypertension, and therefore it has been difficult to investigate aberrations in signaling cascades that precede the development of overt vascular remodeling. This review discusses the role played by both oxidative and nitrosative stress in the lung and their impact on the signaling pathways that regulate vasodilation, vessel growth, and vascular remodeling in the neonatal lung exposed to increased pulmonary blood flow.

Consequences of gestational and pregestational diabetes on placental function and birth weight

Maternal diabetes constitutes an unfavorable environment for embryonic and fetoplacental development. Despite current treatments, pregnant women with pregestational diabetes are at increased risk for congenital malformations, materno-fetal complications, placental abnormalities and intrauterine malprogramming. The complications during pregnancy concern the mother (gravidic hypertension and/or preeclampsia, cesarean section) and the fetus (macrosomia or intrauterine growth restriction, shoulder dystocia, hypoglycemia and respiratory distress). The fetoplacental impairment and intrauterine programming of diseases in the offspring’s later life induced by gestational diabetes are similar to those induced by type 1 and type 2 diabetes mellitus. Despite the existence of several developmental and morphological differences in the placenta from rodents and women, there are similarities in the alterations induced by maternal diabetes in the placenta from diabetic patients and diabetic experimental models. From both human and rodent diabetic experimental models, it has been suggested that the placenta is a compromised target that largely suffers the impact of maternal diabetes. Depending on the maternal metabolic and proinflammatory derangements, macrosomia is explained by an excessive availability of nutrients and an increase in fetal insulin release, a phenotype related to the programming of glucose intolerance. The degree of fetal damage and placental dysfunction and the availability and utilisation of fetal substrates can lead to the induction of macrosomia or intrauterine growth restriction. In maternal diabetes, both the maternal environment and the genetic background are important in the complex and multifactorial processes that induce damage to the embryo, the placenta, the fetus and the offspring. Nevertheless, further research is needed to better understand the mechanisms that govern the early embryo development, the induction of congenital anomalies and fetal overgrowth in maternal diabetes.

Non-thermal dielectric barrier discharge plasma induces angiogenesis through reactive oxygen species

Vascularization plays a key role in processes such as wound healing and tissue engineering. Non-thermal plasma, which primarily produces reactive oxygen species (ROS), has recently emerged as an efficient tool in medical applications including blood coagulation, sterilization and malignant cell apoptosis. Liquids and porcine aortic endothelial cells were treated with a non-thermal dielectric barrier discharge plasma in vitro. Plasma treatment of phosphate-buffered saline (PBS) and serum-free medium increased ROS concentration in a dose-dependent manner, with a higher concentration observed in serum-free medium compared with PBS. Species concentration inside cells peaked 1 h after treatment, followed by a decrease 3 h post treatment. Endothelial cells treated with a plasma dose of 4.2 J cm(-2) had 1.7 times more cells than untreated samples 5 days after plasma treatment. The 4.2 J cm(-2) plasma dose increased two-dimensional migration distance by 40 per cent compared with untreated control, while the number of cells that migrated through a three-dimensional collagen gel increased by 15 per cent. Tube formation was also enhanced by plasma treatment, with tube lengths in plasma-treated samples measuring 2.6 times longer than control samples. A fibroblast growth factor-2 (FGF-2) neutralizing antibody and ROS scavengers abrogated these angiogenic effects. These data indicate that plasma enhanced proliferation, migration and tube formation is due to FGF-2 release induced by plasma-produced ROS. Non-thermal plasma may be used as a potential tool for applying ROS in precise doses to enhance vascularization.

HIF-1α in epidermis: oxygen sensing, cutaneous angiogenesis, cancer, and non-cancer disorders

Besides lung, postnatal human epidermis is the only epithelium in direct contact with atmospheric oxygen. Skin epidermal oxygenation occurs mostly through atmospheric oxygen rather than tissue vasculature, resulting in a mildly hypoxic microenvironment that favors increased expression of hypoxia-inducible factor-1α (HIF-1α). Considering the wide spectrum of biological processes, such as angiogenesis, inflammation, bioenergetics, proliferation, motility, and apoptosis, that are regulated by this transcription factor, its high expression level in the epidermis might be important to HIF-1α in skin physiology and pathophysiology. Here, we review the role of HIF-1α in cutaneous angiogenesis, skin tumorigenesis, and several skin disorders.

Green tea extract given before regional myocardial ischemia-reperfusion in rats improves myocardial contractility by attenuating calcium overload

There is evidence for a negative correlation between green tea consumption and cardiovascular diseases. The aim of the present study was to examine whether green tea extract (GTE) given before regional myocardial ischemia could improve depression of myocardial contractility by preventing cytosolic Ca(2+) overload. Regional ischemia-reperfusion (IR) was induced in rats by ligating the left anterior descending branch for 20 min, then releasing the ligature. Ligation induced ventricular arrhythmias in rats without GTE pretreatment, but decreased arrhythmogenesis was seen in rats pretreated 30 min earlier with GTE (400 mg/kg). During reperfusion, arrhythmias only occurred during the initial 5 min, and GTE pretreatment had no effect. After overnight recovery, serum cTnI levels were greatly increased in control post-IR rats but only slightly elevated in GTE-pretreated post-IR rats. Myocardial contractility measured by echocardiography was still depressed after 3 days in control post-IR rats, but not in GTE-pretreated post-IR rats. No myocardial ischemic injury was seen in post-IR rats with or without GTE pretreatment. Using freshly isolated single heart myocytes, GTE was found to attenuate the post-IR injury-associated cytosolic Ca(2+) overload and modulate changes in the levels and distribution of myofibril, adherens junction, and gap junction proteins. In summary, GTE pretreatment protects cardiomyocytes from IR injury by preventing cytosolic Ca(2+) overload, myofibril disruption, and alterations in adherens and gap junction protein expression and distribution.

Acidic and basic fibroblast growth factors involved in cardiac angiogenesis following infarction

Acidic and basic fibroblast growth factors (FGF-1/FGF-2) promote angiogenesis in cancer. Angiogenesis is integral to cardiac repair following myocardial infarction (MI). The potential regulation of FGF-1/FGF-2 in cardiac angiogenesis postMI remains unexplored. Herein, we examined the temporal and spatial expression of FGF-1/FGF-2 and FGF receptors (FGFR) in the infarcted rat heart at days 1, 3, 7, and 14 postMI. FGF-1/-2 gene and protein expression, cells expressing FGF-1/-2 and FGFR expression were examined by quantitative in situ hybridization, RT-PCR; western blot, immunohistochemistry and quantitative in vitro autoradiography. Compared to the normal heart, we found that in the border zone and infarcted myocardium 1) FGF-1 gene expression was increased in the first week postMI and returned to control levels at week 2; FGF-1 protein levels were, however, largely reduced at day 1, then elevated at day 3 peaked at day 7 and declined at day 14; and cells expressing FGF-1 were primarily inflammatory cells; 2) FGF-2 gene expression was significantly elevated from day 1 to day 14; the increase in FGF-2 protein level was most evident at day 7 and cells expressing FGF-2 were primarily endothelial cells; 3) FGFR expression started to increase at day 3 and remained elevated thereafter; and 4) FGF-1/FGF-2 and FGFR expression remained unchanged in the noninfarcted myocardium. Thus, FGF-1/FGF-2 and FGFR expression are enhanced in the infarcted myocardium in the early stage after MI, which is spatially and temporally coincident with angiogenesis, suggesting that FGF-1/FGF-2 are involved in regulating cardiac angiogenesis and repair.

Fat depot-specific differences in angiogenic growth factor gene expression and its relation to adipocyte size in cattle

Adipocytes derived from different anatomical sites vary in the expression of adipocytokines and growth factor genes. Adipogenesis is tightly associated with angiogenesis, although the regional variation of angiogenic growth factor gene expression in adipose tissues remains unclear. In this experiment, we studied the fat depot-specific differences (subcutaneous, intramuscular, intermuscular, renal, and mesenteric) in the expression of angiogenic growth factor mRNA [vascular endothelial growth factor (VEGF), fibroblast growth factor-2 (FGF-2), fibroblast growth factor-10 (FGF-10), hepatocyte growth factor (HGF), and leptin], as well as the relationship between angiogenic growth factor mRNA level and adipocyte size in bovine adipose tissues. Intermuscular, renal, and mesenteric adipose tissues expressed significantly higher VEGF, FGF-2, and leptin mRNA levels than did subcutaneous and intramuscular adipose tissues. Mesenteric adipose tissue also expressed higher FGF-10 mRNA levels than did subcutaneous and intramuscular adipose tissues. There was no significant difference in the expression of HGF mRNA among adipose tissue depots. A significant correlation existed between adipocyte size and VEGF, FGF-2, FGF-10, and leptin mRNA levels. These results indicate that fat depot-specific difference in angiogenic growth factor gene expression results from the difference in adipocyte size.

Redox control of vascular smooth muscle migration

Vascular smooth muscle cell migration is important during vascular development and contributes to lesion formation in the adult vasculature. The mechanisms regulating migration of this cell type are therefore of great interest. Recent work has shown that reactive oxygen species (ROS) derived from NADPH oxidases are important mediators of promigratory signaling pathways. ROS regulate the intracellular signals responsible for lamellipodia formation, actin cytoskeleton remodeling, focal adhesion turnover, and contraction of the cell body. In addition, they contribute to matrix remodeling, a critical step to initiate and support vascular smooth muscle cell motility. Despite these recent advances in our understanding of the redox mechanisms that contribute to migration, additional work is needed to evaluate fully the potential of ROS-sensitive molecular signals as therapeutic targets to prevent inappropriate smooth muscle cell migration.

Effect of arachidonic acid on hypoxia-induced IL-6 production in mouse ES cells: Involvement of MAPKs, NF-kappaB, and HIF-1alpha

This study examined the role of arachidonic acid (AA) in hypoxia-induced production of interleukin (IL)-6 and its related signaling pathways in mouse embryonic stem (ES) cells. Hypoxia with AA induced IL-6 production, which was mediated by reactive oxygen species (ROS). In addition, hypoxia increased the levels of p38 mitogen-activated protein kinases (MAPKs) and stress-activated protein kinase/c-jun NH(2)-terminal kinase (SAPK/JNK) phosphorylation, which were blocked by antioxidant (vitamin C). Inhibition of p38 MAPK and SAPK/JNK blocked hypoxia- or hypoxia with AA-induced nuclear factor-kappa B (NF-kappaB) activation. Furthermore, hypoxia-induced increase in hypoxia-inducible factor-1alpha (HIF-1alpha) expression was regulated by NF-kappaB activation. Consequently, the increased HIF-1alpha expression induced activation of matrix metalloproteinase (MMP)-2 and MMP-9. The expression of each signaling molecule stimulated an increase in IL-6 production that was greater in hypoxic conditions with AA than with hypoxia alone. Finally, inhibition of IL-6 production using IL-6 antibody or soluble IL-6 receptor attenuated the hypoxia-induced increases in DNA synthesis of mouse ES cells. In conclusion, AA potentiates hypoxia-induced IL-6 production through the MAPKs, NF-kappaB, and HIF-1alpha pathways in mouse ES cells.

Inhibition of mTOR attenuates store-operated Ca2+ entry in cells from endarterectomized tissues of patients with chronic thromboembolic pulmonary hypertension

Pulmonary vascular remodeling occurs in patients with chronic thromboembolic pulmonary hypertension (CTEPH). One factor contributing to this vascular wall thickening is the proliferation of pulmonary artery smooth muscle cells (PASMC). Store-operated Ca(2+) entry (SOCE) and cytosolic free Ca(2+) concentration ([Ca(2+)](cyt)) in PASMC are known to be important in cell proliferation and vascular remodeling in pulmonary hypertension. Rapamycin is widely known for its antiproliferative effects in injured coronary arteries. Although several reports have suggested favorable effects of rapamycin in animal models of pulmonary hypertension, no reports have been published to date in human tissues. Here we report that rapamycin has an inhibitory effect on SOCE and an antiproliferative effect on PASMC derived from endarterectomized tissues of CTEPH patients. Cells were isolated from endarterectomized tissues obtained from patients undergoing pulmonary thromboendarterectomy (PTE). Immunohistochemical analysis indicated high deposition of platelet-derived growth factor (PDGF) in tissue sections from PTE tissues and increased PDGF receptor expression. PDGF transiently phosphorylated Akt, mammalian target of rapamycin (mTOR), and p70S6 kinase in CTEPH cells from CTEPH patients. Acute treatment (30 min) with rapamycin (10 nM) slightly increased cyclopiazonic acid (10 microM)-induced Ca(2+) mobilization and significantly reduced SOCE. Chronic treatment (24 h) with rapamycin reduced Ca(2+) mobilization and markedly inhibited SOCE. The inhibitory effects of rapamycin on SOCE were less prominent in control cells. Rapamycin also significantly reduced PDGF-stimulated cell proliferation. In conclusion, the data from this study indicate the importance of the mTOR pathway in the development of pulmonary vascular remodeling in CTEPH and suggest a potential therapeutic benefit of rapamycin (or inhibition of mTOR) in these patients.

Expression and function of NFAT5 in medullary thick ascending limb (mTAL) cells

The contribution of nuclear factor of activated T cells 5 (NFAT5) to the regulation of tumor necrosis factor-alpha (TNF) production in medullary thick ascending limb (mTAL) cells is unclear. RT-PCR analysis was performed on primary cultures of mouse mTAL cells and freshly isolated mTAL tubules to determine which NFAT isoforms are present in this nephron segment. Primer pairs were designed, based on published sequences for mouse NFAT1-5, to produce fragments of approximately 200 bp. Analysis of PCR products by gel electrophoresis and subsequent DNA sequencing indicated that cells and tubules contained mRNA for all five NFAT isoforms. The relative expression of NFAT isoforms was then determined using quantitative real-time RT-PCR. The data indicate that NFAT isoforms 5 >/= 1 are the predominant isoforms present in mTAL cells and tubules. Western blot analysis demonstrated constitutive expression of NFAT5 in nuclear extracts from mTAL tubules and primary culture cells; expression in mTAL cells also was detected by immunofluorescence. Expression of NFAT5 was increased in mTAL cells transiently transfected with an NFAT5 overexpression vector (pcDNA3.1-NFAT5), resulting in increased basal and calcium-sensing receptor (CaR)-mediated TNF production. Transient transfection of mTAL cells with a small hairpin RNA vector that targeted exon 8 of NFAT5 (U6-N5 ex8) significantly inhibited TNF promoter activity. Transient transfection with U6-N5 ex8 also reduced nuclear expression of NFAT5, TNF mRNA accumulation, and attenuated CaR-mediated activation of Cl(-) entry into polarized mTAL cells. Collectively, these data suggest that activation of NFAT5 is part of a TNF-dependent pathway that inhibits apical Cl(-) influx in the mTAL after activation of CaR.