Reaction of Mast Cells in the Zone of Polypropylene Mesh Implantation.

Reaction of mast cells of adult male Wistar rats (n=15) in the zone of polypropylene mesh fixation was studied by histochemical, immunohistochemical, and traditional morphological methods on days 1, 5, 10, and 30 after implantation. Immediately after the intervention, mast cells stimulated the processes aimed at wound healing. Secretion of mast cells was clearly regulatory. These cells migrated to the zone of injury for subsequent activation of their function. The number of cNOS+ mast cells near the polypropylene mesh was maximum on day 1 and the number of iNOS+ mast cells peaked on day 5 of the experiment, which probably represented a compensatory reaction. Presumably, stimulation of fibrillogenesis was largely due to the activatory effect of mast cells on the fibroblast function, but not to collagen production by these mast cells.

The vasa vasorum reach deep into the human thoracic aorta.

Only limited data are available on the extent of the vasa vasorum of the human thoracic aorta, although this could be important with regard to certain pathophysiological states, i.e. aortic aneurysm or atherosclerosis. A preliminary investigation shows that the vascularization of the human thoracic aorta reaches deeper layers than generally believed.

Calreticulin induced endothelial ICAM-1 up-regulation associated with tristetraprolin expression alteration through PI3K/Akt/eNOS/p38 MAPK signaling pathway in rheumatoid arthritis.

The present study was undertaken to determine whether extracellular calreticulin (CRT) participates in the regulation of ICAM-1in rheumatoid arthritis (RA) and further explore the potential mechanism. Our results showed that ICAM-1 and VCAM-1 levels were positively correlated with CRT levels in RA serum and synovial fluid, respectively. In RA synovial tissue, increased co-expressions of CRT and ICAM-1 in vascular endothelium and perivascular areas and elevated co-location of CRT and VCAM-1 localized predominantly to lining layer were observed compared to those in OA. In in vitro HUVECs model, enhanced ICAM-1expression and increased phosphorylation levels of Akt and eNOS were detected in the presence of CRT. Increased phosphorylated eNOS was significantly inhibited by a PI3K inhibitor LY294002 and elevated ICAM-1expression was partially blocked by the inhibitors of both PI3K and eNOS (L-NAME). It has been certified that the RNA-binding protein TTP targets AU-rich elements in the ICAM-1 3'-UTR and suppresses ICAM-1 expression. Knocking down TTP in HUVECs led to an increased induction of ICAM-1 by CRT. We have currently known that activation of p38 downstream kinase MK-2 leads to phosphorylation and inactivation of human TTP. The block of p38 MAPK/MK-2 signaling led to decreased protein expression and mRNA stability of TTP and ICAM-1. Furthermore, L-NAME and/or LY294002 pre-treated HUVECs manifested decreased p38 and MK-2 phosphorylation, which was accompanied by reduced TTP and ICAM-1 protein expression as well as decreased mRNA stability. Our results suggested that CRT could promote ICAM-1 expression in endothelial cells through PI3K/Akt/eNOS/p38 MAPK signaling mediated TTP accumulation, probably in an inactive form, which may provide a possible proinflammatory mechanism of CRT in RA.

Pyridinecarboxylic Acid Derivative Stimulates Pro-Angiogenic Mediators by PI3K/AKT/mTOR and Inhibits Reactive Nitrogen and Oxygen Species and NF-κB Activation Through a PPARγ-Dependent Pathway in T. cruzi-Infected Macrophages.

Chagas disease is caused by Trypanosoma cruzi infection and represents an important public health concern in Latin America. Macrophages are one of the main infiltrating leukocytes in response to infection. Parasite persistence could trigger a sustained activation of these cells, contributing to the damage observed in this pathology, particularly in the heart. HP24, a pyridinecarboxylic acid derivative, is a new PPARγ ligand that exerts anti-inflammatory and pro-angiogenic effects. The aim of this work was to deepen the study of the mechanisms involved in the pro-angiogenic and anti-inflammatory effects of HP24 in T. cruzi-infected macrophages, which have not yet been elucidated. We show for the first time that HP24 increases expression of VEGF-A and eNOS through PI3K/AKT/mTOR and PPARγ pathways and that HP24 inhibits iNOS expression and NO release, a pro-inflammatory mediator, through PPARγ-dependent mechanisms. Furthermore, this study shows that HP24 modulates H2O2 production in a PPARγ-dependent manner. It is also demonstrated that this new PPARγ ligand inhibits the NF-κB pathway. HP24 inhibits IKK phosphorylation and IκB-α degradation, as well as p65 translocation to the nucleus in a PPARγ-dependent manner. In Chagas disease, both the sustained increment in pro-inflammatory mediators and microvascular abnormalities are crucial aspects for the generation of cardiac damage. Elucidating the mechanism of action of new PPARγ ligands is highly attractive, given the fact that it can be used as an adjuvant therapy, particularly in the case of Chagas disease in which inflammation and tissue remodeling play an important role in the pathophysiology of this disease.

Unexpected role of the human cytomegalovirus contribute to essential hypertension in the Kazakh Chinese population of Xinjiang.

Human cytomegalovirus (HCMV) infection, chronic inflammation and oxidative stress, the renin-angiotensin system (RAS), endothelial function, and DNA methylation play roles in the pathogenesis of essential hypertension (EH); however, the mechanism by which HCMV predisposes patients to hypertension remain unclear. Our group previously demonstrated an association between EH and HCMV infection in Kazakh Chinese. Here, we investigated the relationship between HCMV infection and other clinicopathological features in 720 Kazakh individuals with or without hypertension (n=360 each; age: 18-80). Multiple linear and logistic regression analyses were used to determine the associations between HCMV infection, clinical characteristics, and EH. Notably, patients with EH, particularly those with HCMV infection, exhibited a marked increase in tumor necrosis factor-α (TNF-α) and 8-hydroxy-2-deoxyguanosine (8-OHDG) levels, but a decrease in endothelial nitric oxide synthase (eNOS) and renin levels. Similarly, elevated TNF-α and 8-OHDG levels were independent predictors of increased HCMV antibody titers, whereas eNOS and renin were negatively correlated with the latter. Moreover, serum angiotensin-converting enzyme (sACE, ACE) methylation was increased, whereas 11-ß hydroxysteroid dehydrogenase 2 (HSD11ß2; HSD3B2) methylation was decreased in patients with EH who were also infected with HCMV. A positive correlation between HSD3B2 methylation and HCMV IgG titer and blood pressure was additionally observed, whereas angiotensin-converting enzyme (ACE) methylation was inversely correlated with blood pressure. Collectively, these data indicate that HCMV may contribute to EH development in the Kazakh Chinese by increasing TNF-α and 8-OHDG levels, suppressing eNOS and renin, and manipulating HSD3B2 and ACE methylation.

[Afalaza in the management of patients with chronic pelvic pain syndrome].

INTRODUCTION: Currently, chronic pelvic pain syndrome (CPPS) is one of the most prevalent urological diseases, but due to the multifactorial nature of the disease and the lack of consensus on its pathogenesis, the issue of adequate therapy remains open. Since the vascular factor plays the major role in the pathogenesis of CPPS, we hypothesized that this category of patients has microcirculatory disturbances of the prostate. AIM: Detection of microcirculatory disturbances of the prostate, their correction, and evaluation of the effect on the course of CPPS. MATERIALS AND METHODS: The study comprised 60 healthy, sexually active men with clinical manifestations of CPPS lasting from 6 months to 5 years. After a comprehensive examination, all patients received Afalaza 2 tablets twice daily for 16 weeks. At the end of week 16, patients were re-examined. RESULTS: In patients with CPPS, therapy with Afalaza resulted in a significant improvement in microcirculation in the prostate thus leading to the reduction of the severity of disease manifestations.

Toll-like receptor 4 (TLR4) impairs nitric oxide contributing to Angiotensin II-induced cavernosal dysfunction.

AIM: Angiotensin II (AngII), a corpus cavernosum (CC) constrictor peptide, modulates Toll like receptor (TLR) expression, a key element of the innate immune system, contributing to impaired vascular function in pathological conditions. However, it is unknown whether TLR4 is involved in AngII-induced erectile dysfunction. In this study, we investigated whether TLR4 plays a role in cavernosal dysfunction caused by AngII upregulation. MATERIAL AND METHODS: Cavernosal smooth muscle cells (CSMC) from C57/BL6 mice were treated with AngII (0.1µM) or bacterial LPS (50ng/ml) for 12-24h and TLR4 expression was assessed. Mice were infused with AngII (90ng/min, 28days) and treated with anti-TLR4 antibody (0.1mg/daily, i.p.) for the last 14days of the treatment. CC tissue was used for functional studies and for Western blotting. Nitric Oxide Synthase (NOS) activity was measured by conversion of [3H]-l-arginine to [3H]-l-citrulline, systemic TNF-α levels by ELISA, and reactive oxygen species (ROS) by immunofluorescence. KEY FINDINGS: We report upregulation of TLR4 in CSMC following AngII or LPS stimulation. In AngII-infused mice, chronic treatment with anti-TLR4 antibody (28±2.1%) attenuates adrenergic CC contraction, which also ameliorates nitrergic (68.90±0.21 vs. 51.07±0.63, 8Hz, AngII-infused mice treated vs. non-treated). Decreased endothelial NOS expression, reduced NOS activity, and augmented levels of TNF-α, and ROS were found following AngII-infusion. These alterations were prevented, or at least decreased by anti-TLR4 antibody treatment. SIGNIFICANCE: Inhibition of TLR4 ameliorates AngII-impaired cavernosal relaxation, decreases TNF-α levels, and restores NO bioavailability, demonstrating that TLR4 partly mediates AngII-induced cavernosal dysfunction.

Green tea infusion protects against alcoholic liver injury by attenuating inflammation and regulating the PI3K/Akt/eNOS pathway in C57BL/6 mice.

Alcohol intake is a major risk factor for the pathogenesis of alcoholic liver diseases. Accumulating evidence suggests that green tea protects against alcoholic liver injury; however, the underlying mechanisms remain unclear. The present study investigated the role of endothelial nitric oxide synthase (eNOS) in the protective effects of green tea against alcohol-induced liver injury and inflammation. Ethanol was intragastrically administered to male C57BL/6 mice once a day, and the mice were allowed free access to green tea infusion or water for two weeks. We assessed the plasma levels of alanine aminotransferase and aspartate aminotransferase, hepatic contents of thiobarbituric acid reactive substances, malondialdehyde and triglyceride and hepatic mRNA expression of pro-inflammatory cytokines (interleukin-1ß, tumor necrosis factor-α, and interleukin-6). Our results showed that compared with water alone, green tea infusion markedly reduced liver damage, hepatic oxidative stress, hepatic lipid accumulation and inflammatory response. Green tea infusion also significantly reduced hepatic nuclear factor-κB expression and its downstream inflammatory mediators (inducible nitric oxide synthase and cyclooxygenase-2) mRNA levels in ethanol-treated mice. Additionally, green tea infusion significantly activated hepatic phosphorylated phosphatidylinositol 3-kinase (PI3K) and phosphorylated protein kinase B (Akt), which are associated with the upregulation of phosphorylated eNOS expression and the increase of plasma nitric oxide levels in ethanol-treated mice. Furthermore, the protective effects of green tea infusion were considerably inhibited by the eNOS inhibitor NG-nitro-l-arginine methyl ester in ethanol-treated mice. In conclusion, our study demonstrated that the protective effects of green tea infusion on alcohol-induced liver injury and inflammation involve the modulation of the PI3K/AKT/eNOS pathway.

[Modern view on etiology, pathogenesis and treatment of chronic pelvic pain syndrome].

The manuscript presents the analysis of scientific manuscripts written by Russian and foreign researchers devoted to chronic pelvic pain syndrome (CPPS) studies. In spite of widespread disease, there is no clear understanding on etiopathogenetic mechanisms of CPPS development and it is shown that besides infectious process cardiovascular, neuronal, locomotor, endocrine and immune systems are involved into pathological process of CPPS. Mentioned factors complicate the doctors task on effective therapy choice and stress the reasonability of complex approach to CPPS treatment. Combination drug containing affinity purified antibodies to endothelial NO-synthase and prostate-specific antigen in released-active form influences different pathogenetic mechanisms of CPPS and thereby reveals pronounced clinical efficacy.

Methotrexate improves perivascular adipose tissue/endothelial dysfunction via activation of AMPK/eNOS pathway.

Adipose and endothelial dysfunction is associated with cardiovascular disease. Perivascular adipose tissue (PVAT) directly surrounds vessels and influences vessel function via a paracrine effect, and adenosine monophosphate (AMP)-activated protein kinase (AMPK) modulates the metabolic pathway, thus, the present study hypothesized that activation of AMPK in PVAT may regulate endothelial function in pathological settings. The present study investigated the effect of methotrexate (MTX) on adipocytokine expression in PVAT with an emphasis on the regulation of endothelial function. The effects of MTX and the mechanisms involved were investigated using a relaxation assay and western blot analysis. Reverse transcription­quantitative polymerase chain reaction and western blotting were used to detect the mRNA and protein expression levels. ELISA assay was used to quantify the level of TNF­α and IL­6. Palmitic acid (PA) stimulation induced inflammation and dysregulation of adipocytokine expression in PVAT. MTX treatment inhibited nuclear factor­κB p65 phosphorylation and downregulated expression of pro­inflammatory cytokines, including tumor necrosis factor­α and interleukin-6, whereas adiponectin expression increased. MTX increased AMPK phosphorylation under basal and inflammatory conditions in PVAT, whereas knockdown of AMPK via small interfering RNA diminished its modulatory effect, indicating that MTX inhibits inflammation in an AMPK­dependent manner. The present study prepared conditioned medium from PA­stimulated PVAT to induce endothelial dysfunction and observed that pre­treatment of PVAT with MTX effectively restored the loss of acetylcholine­induced vasodilation and increased endothelial nitric oxide synthase phosphorylation in the rat aorta. The results of the present study demonstrated that MTX ameliorated inflammation-associated adipocytokine dysregulation and thus prevented endothelial dysfunction. These data provide further pharmacological evidence regarding the beneficial effects of MTX in cardiovascular diseases.

Omentin protects against LPS-induced ARDS through suppressing pulmonary inflammation and promoting endothelial barrier via an Akt/eNOS-dependent mechanism.

Acute respiratory distress syndrome (ARDS) is characterized by increased pulmonary inflammation and endothelial barrier permeability. Omentin has been shown to benefit obesity-related systemic vascular diseases; however, its effects on ARDS are unknown. In the present study, the level of circulating omentin in patients with ARDS was assessed to appraise its clinical significance in ARDS. Mice were subjected to systemic administration of adenoviral vector expressing omentin (Ad-omentin) and one-shot treatment of recombinant human omentin (rh-omentin) to examine omentin's effects on lipopolysaccharide (LPS)-induced ARDS. Pulmonary endothelial cells (ECs) were treated with rh-omentin to further investigate its underlying mechanism. We found that a decreased level of circulating omentin negatively correlated with white blood cells and procalcitonin in patients with ARDS. Ad-omentin protected against LPS-induced ARDS by alleviating the pulmonary inflammatory response and endothelial barrier injury in mice, accompanied by Akt/eNOS pathway activation. Treatment of pulmonary ECs with rh-omentin attenuated inflammatory response and restored adherens junctions (AJs), and cytoskeleton organization promoted endothelial barrier after LPS insult. Moreover, the omentin-mediated enhancement of EC survival and differentiation was blocked by the Akt/eNOS pathway inactivation. Therapeutic rh-omentin treatment also effectively protected against LPS-induced ARDS via the Akt/eNOS pathway. Collectively, these data indicated that omentin protects against LPS-induced ARDS by suppressing inflammation and promoting the pulmonary endothelial barrier, at least partially, through an Akt/eNOS-dependent mechanism. Therapeutic strategies aiming to restore omentin levels may be valuable for the prevention or treatment of ARDS.

Estrogen increases the severity of anaphylaxis in female mice through enhanced endothelial nitric oxide synthase expression and nitric oxide production.

BACKGROUND: Clinical observations suggest that anaphylaxis is more common in adult women compared with adult men, although the mechanistic basis for this sex bias is not well understood. OBJECTIVES: We sought to document sex-dependent differences in a mouse model of anaphylaxis and explore the role of female sex hormones and the mechanisms responsible. METHODS: Passive systemic anaphylaxis was induced in female and male mice by using histamine, as well as IgE or IgG receptor aggregation. Anaphylaxis was assessed by monitoring body temperature, release of mast cell mediators and/or hematocrit, and lung weight as a measure of vascular permeability. A combination of ovariectomy, estrogen receptor antagonism, and estrogen administration techniques were used to establish estrogen involvement. RESULTS: Anaphylactic responses were more pronounced in female than male mice. The enhanced severity of anaphylaxis in female mice was eliminated after pretreatment with an estrogen receptor antagonist or ovariectomy but restored after administration of estradiol in ovariectomized mice, demonstrating that the sex-specific differences are due to the female steroid estradiol. Estrogen did not affect mast cell responsiveness or anaphylaxis onset. Instead, it increased tissue expression of endothelial nitric oxide synthase (eNOS). Blockage of NOS activity with the inhibitor L-NG-nitroarginine methyl ester or genetic eNOS deficiency abolished the sex-related differences. CONCLUSION: Our study defines a contribution of estrogen through its regulation of eNOS expression and nitric oxide production to vascular hyperpermeability and intensified anaphylactic responses in female mice, providing additional mechanistic insights into risk factors and possible implications for clinical management in the further exploration of human anaphylaxis.

Post-Translational Nitric Oxide-Dependent Modifications In Immune System.

Nitric oxide non classical signalling is exerted through a series of covalent protein post-translational modifications, which include modification of cysteine residues by S-nitrosylation and S-glutathionylation. A key process in adaptive immunity is the immune synapse that tightly couples T cells with antigen presenting cells, triggering antigen recognition by T cells. In this highly regulated process, we have shown that eNOS is activated, inducing protein S-nitrosylation. While both N-Ras and K-Ras are present in T cells, only N-Ras, which colocalizes in the Golgi with eNOS, is S-nitrosylated and activated during the immune synapse, providing an example of short-range selectivity of NO signalling through S-nitrosylation. We have developed proteomic methods to detect S-nitrosylation and reversible cysteine oxidations. We have applied them to detecting S-nitrosylated proteins in macrophage activation, highlighting the role of denitrosylase mechanism, particularly the thioredoxin pathway, in protecting macrophages from self-modification. We have also applied these proteomic methods to studying protein modification in acute hypoxia. In endothelial cells, there is an increase in cysteine oxidation in several proteins that can mediate acute responses to hypoxia prior to the activation of the HIF pathway, and we are currently studying in more detail the role of protein S-nitrosylation. We have also recently shown that acute hypoxia produces a superoxide burst in cells, which can be converted in an oxidative signal through protein cysteine modification, and we are unraveling the molecular mechanisms producing this superoxide burst in mitochondria.

Red wine extract decreases pro-inflammatory markers, nuclear factor-κB and inducible NOS, in experimental metabolic syndrome.

We aimed to analyse the effects of alcohol-free Alibernet red wine extract (AWE) on nitric oxide synthase (NOS) activity and pro-inflammatory markers such as nuclear factor-κB (NFκB) and inducible NOS (iNOS) protein expression in experimental metabolic syndrome. Young 6 week-old male Wistar Kyoto (WKY) and obese, spontaneously hypertensive rats (SHR/N-cp) were divided into control groups and groups treated with AWE (24.2 mg per kg per day) for 3 weeks (n = 6 in each group). Total NOS activity and endothelial NOS (eNOS), iNOS and NFκB (p65) protein expressions were determined in the heart left ventricle and aorta by Western blot and immunohistochemical analysis. All parameters investigated significantly increased in the aorta of SHR/N-cp rats. Pro-inflammatory markers such as NFκB and iNOS were increased in the left ventricle as well. AWE treatment did not affect total NOS activity and eNOS expression in the aorta; however, it was able to decrease NFκB and iNOS protein expression in both the left ventricle and aorta. In conclusion, in the cardiovascular system, Alibernet red wine extract decreased NFκB and iNOS protein expressions elevated as a consequence of developed metabolic syndrome. This effect may represent one of the protective, anti-inflammatory properties of Alibernet red wine polyphenols on cardiovascular risk factors related to metabolic syndrome.

Endothelial nitric oxide synthase protects neurons against ischemic injury through regulation of brain-derived neurotrophic factor expression.

AIMS: Several lines of evidence demonstrated that endothelial nitric oxide synthase (eNOS) confers protective effects during cerebral ischemia. In this study, we explored the underlying cellular and molecular mechanisms of neuroprotection by eNOS. METHODS: A series of in vivo and in vitro ischemic models were employed to study the role of eNOS in maintaining neuronal survival and to identify the downstream factors. RESULTS: The current data showed that pretreatment with a specific eNOS inhibitor, L-N5-(1-iminoethyl) ornithine (L-NIO), aggravated the neuronal loss in the rat cerebral ischemic model, accompanied by reduction in brain-derived neurotrophic factor (BDNF) level, which was consistent with the findings in an oxygen-glucose deprivation model (OGD) with two neuronal cells: primary rat cortical neurons and human neuroblastoma SH-SY5Y cells. Furthermore, the extensive neuronal loss induced by L-NIO was totally abolished by exogenous BDNF in both in vitro and in vivo models. On the other hand, eNOS overexpression through an adenoviral vector exerted a prominent protective effect on the neuronal cells subject to OGD, and the protective effect was totally abrogated by a neutralizing anti-BDNF antibody. CONCLUSION: Collectively, our results indicate that the neuroprotection of neuron-derived eNOS against the cerebral ischemia was mediated through the regulation of BDNF secretion. In conclusion, our discovery provides a novel explanation for the neuroprotective effect of eNOS under pathological ischemic conditions such as stroke.

LPS induces pp60c-src-mediated tyrosine phosphorylation of Hsp90 in lung vascular endothelial cells and mouse lung.

Heat shock protein 90 (Hsp90) inhibitors were initially developed as anticancer agents; however, it is becoming increasing clear that they also possess potent anti-inflammatory properties. Posttranslational modifications of Hsp90 have been reported in tumors and have been hypothesized to affect client protein- and inhibitor-binding activities. In the present study we investigated the posttranslational modification of Hsp90 in inflammation. LPS, a prototypical inflammatory agent, induced concentration- and time-dependent tyrosine (Y) phosphorylation of Hsp90α and Hsp90ß in bovine pulmonary arterial and human lung microvascular endothelial cells (HLMVEC). Mass spectrometry identified Y309 as a major site of Y phosphorylation on Hsp90α (Y300 of Hsp90ß). LPS-induced Hsp90 phosphorylation was prevented by the Hsp90 inhibitor 17-allyl-amino-demethoxy-geldanamycin (17-AAG) in vitro as well as in lungs from LPS-treated mice, in vivo. Furthermore, 17-AAG prevented LPS-induced pp60src activation. LPS-induced Hsp90 phosphorylation was also prevented by the pp60src inhibitor PP2. Additionally, Hsp90 phosphorylation was induced by infecting cells with a constitutively active pp60src adenovirus, whereas either a dominant-negative pp60src adenovirus or reduced expression of pp60src by a specific siRNA prevented the LPS-induced Y phosphorylation of Hsp90. Transfection of HLMVEC with the nonphosphorylatable Hsp90ß Y300F mutant prevented LPS-induced Hsp90ß tyrosine phosphorylation but not pp60src activation. Furthermore, the Hsp90ß Y300F mutant showed a reduced ability to bind the Hsp90 client proteins eNOS and pp60src and HLMVEC transfected with the mutant exhibited reduced LPS-induced barrier dysfunction. We conclude that inflammatory stimuli cause posttranslational modifications of Hsp90 that are Hsp90-inhibitor sensitive and may be important to the proinflammatory actions of Hsp90.

Increased intrahepatic resistance in severe steatosis: endothelial dysfunction, vasoconstrictor overproduction and altered microvascular architecture.

Non-alcoholic fatty liver disease can progress to steatohepatitis and fibrosis, and is also associated with impaired liver regeneration. The pathophysiology remains elusive. We recently showed that severe steatosis is associated with an increase in portal pressure, suggesting liver flow impairment. The objective of this study is to directly assess total intrahepatic resistance and its potential functional and structural determinants in an in situ perfusion model. Male Wistar rats fed a control (n = 30) or a methionine-choline-deficient (MCD) diet (n = 30) for 4 weeks were compared. Liver tissue and serum analysis, in vivo haemodynamic measurements, in situ perfusion experiments and vascular corrosion casts were performed. The MCD group showed severe steatosis without inflammation or fibrosis on histology. Serum levels and liver tissue gene expression of interleukin (IL)-6, tumour necrosis factor-α, IL-1ß and interferon-γ, liver tissue myeloperoxidase activity and liver immunohistochemistry with anti-CD68 and anti-α smooth muscle actin were comparable between groups, excluding significant inflammation. Flow-pressure curves were significantly different between groups for all flows (slope values: 0.1636 ± 0.0605 mm Hg/ml/min in controls vs 0.7270 ± 0.0408 mm Hg/ml/min in MCD-fed rats, P < 0.001), indicating an increased intrahepatic resistance, which was haemodynamically significant (portocaval pressure gradient 2.2 ± 1.1 vs 8.2 ± 1.3 mm Hg in controls vs MCD, P<0.001). Dose-response curves to acetylcholine were significantly reduced in MCD-fed rats (P < 0.001) as was the responsiveness to methoxamine (P<0.001). Vascular corrosion casts showed a replacement of the regular sinusoidal anatomy by a disorganized pattern with multiple interconnections and vascular extensions. Liver phosphorylated endothelial NO synthase (eNOS)/eNOS and serum nitrite/nitrate were not increased in severe steatosis, whereas liver thromboxane synthase expression, liver endothelin-1 (ET-1) expression and serum andothelin-1 concentration were significantly increased. Severe steatosis induces a haemodynamically significant increase in intrahepatic resistance, which precedes inflammation and fibrogenesis. Both functional (endothelial dysfunction and increased thromboxane and ET-1 synthesis) and structural factors are involved. This phenomenon might significantly contribute to steatosis-related disease.

RIG-like helicase innate immunity inhibits vascular endothelial growth factor tissue responses via a type I IFN-dependent mechanism.

RATIONALE: Vascular endothelial growth factor (VEGF) regulates vascular, inflammatory, remodeling, and cell death responses. It plays a critical role in normal pulmonary physiology, and VEGF excess and deficiency have been implicated in the pathogenesis of asthma and chronic obstructive pulmonary disease, respectively. Although viruses are an important cause of chronic obstructive pulmonary disease exacerbations and innate responses play an important role in these exacerbations, the effects of antiviral responses on VEGF homeostasis have not been evaluated. OBJECTIVES: We hypothesized that antiviral innate immunity regulates VEGF tissue responses. METHODS: We compared the effects of transgenic VEGF(165) in mice treated with viral pathogen-associated molecular pattern polyinosinic:polycytidylic acid [poly(I:C)], mice treated with live virus, and control mice. MEASUREMENTS AND MAIN RESULTS: Transgenic VEGF stimulated angiogenesis, edema, inflammation, and mucin accumulation. Each of these was abrogated by poly(I:C). These inhibitory effects were dose dependent, noted when poly(I:C) was administered before and after transgene activation, and mediated by a Toll-like receptor-3-independent and RIG-like helicase (RLH)- and type I IFN receptor-dependent pathway. VEGF stimulated the expression of VEGF receptor-1 and poly(I:C) inhibited this stimulation. Poly(I:C) also inhibited the ability of VEGF to activate extracellular signal-regulated kinase-1, Akt, focal adhesion kinase, and endothelial nitric oxide synthase, and aeroallergen-induced adaptive helper T-cell type 2 inflammation. Influenza and respiratory syncytial virus also inhibited VEGF-induced angiogenesis. CONCLUSIONS: These studies demonstrate that poly(I:C) and respiratory viruses inhibit VEGF-induced tissue responses and adaptive helper T-cell type 2 inflammation and highlight the importance of a RLH- and type I IFN receptor-dependent pathway(s) in these regulatory events. They define a novel link between VEGF and antiviral and RLH innate immune responses and a novel pathway that regulates pulmonary VEGF activity.