Cxcl1 monomer-dimer equilibrium controls neutrophil extravasation.

The chemokine Cxcl1 plays a crucial role in recruiting neutrophils in response to infection. The early events in chemokine-mediated neutrophil extravasation involve a sequence of highly orchestrated steps including rolling, adhesion, arrest, and diapedesis. Cxcl1 function is determined by its properties of reversible monomer-dimer equilibrium and binding to Cxcr2 and glycosaminoglycans. Here, we characterized how these properties orchestrate extravasation using intravital microscopy of the cremaster. Compared to WT Cxcl1, which exists as both a monomer and a dimer, the trapped dimer caused faster rolling, less adhesion, and less extravasation. Whole-mount immunofluorescence of the cremaster and arrest assays confirmed these data. Moreover, the Cxcl1 dimer showed impaired LFA-1-mediated neutrophil arrest that could be attributed to impaired Cxcr2-mediated ERK signaling. We conclude that Cxcl1 monomer-dimer equilibrium and potent Cxcr2 activity of the monomer together coordinate the early events in neutrophil recruitment.

T cell functions and organ infiltration by leukemic T cells require cortactin.

T cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy that is still fatal in many cases. T cell blasts are characterized by hyperactivation and strong proliferative and migratory capacities. The chemokine receptor CXCR4 is involved in mediating malignant T cell properties, and cortactin has been shown to control CXCR4 surface localization in T-ALL cells. We have previously shown that cortactin overexpression is correlated with organ infiltration and relapse in B-ALL. However, the role of cortactin in T cell biology and T-ALL remains elusive. Here, we analyzed the functional relevance of cortactin for T cell activation and migration and the implications for T-ALL development. We found that cortactin is upregulated in response to T cell receptor engagement and recruited to the immune synapse in normal T cells. Loss of cortactin caused reduced IL-2 production and proliferation. Cortactin-depleted T cells showed defects in immune synapse formation and migrated less due to impaired actin polymerization in response to T cell receptor and CXCR4 stimulation. Leukemic T cells expressed much higher levels of cortactin compared to normal T cells that correlated with greater migratory capacity. Xenotransplantation assays in NSG mice revealed that cortactin-depleted human leukemic T cells colonized the bone marrow significantly less and failed to infiltrate the central nervous system, suggesting that cortactin overexpression drives organ infiltration, which is a major complication of T-ALL relapse. Thus, cortactin could serve as a potential therapeutic target for T-ALL and other pathologies involving aberrant T cell responses.

Annickia polycarpa extract attenuates inflammation, neutrophil recruitment, and colon damage during colitis.

Inflammatory bowel diseases (IBD) including Crohn's disease (CD) and ulcerative colitis (UC) are complex inflammatory disorders of the digestive tract. Dysfunctional intestinal epithelial barrier, uncontrolled neutrophil recruitment into the colon, and oxidative stress are major features of IBD. IBD cannot be cured, but symptoms can be alleviated with anti-inflammatory drugs, which often show adverse effects. Thus, safer alternative treatment options are needed. Given the known anti-inflammatory properties of Annickia polycarpa extract (APE), we hypothesized that APE improves the outcome of the inflammatory response during colitis. We assessed APE effects on colon histology, epithelial barrier function and neutrophil recruitment during DSS-induced colitis in mice treated with APE. APE treatment significantly reduced the disease activity index and prevented DSS-induced colon damage as evidenced by reduced colon shortening, ulcerations, crypt dysplasia, edema formation, and leukocyte infiltration. Expression of the pro-inflammatory cytokines TNF-α, IL-6, and IL-1ß were significantly diminished in APE-treated mice. Importantly, APE administration reduced neutrophil infiltration into the lamina propria leading to reduced oxidative stress, tight junction disruption and epithelial permeability in the colon. Thus, we propose APE as additional treatment strategy to attenuate colitis symptoms and enhance life quality of individuals with IBD.

The Actin-Binding Protein Cortactin Promotes Sepsis Severity by Supporting Excessive Neutrophil Infiltration into the Lung.

Sepsis is a systemic infection that can lead to multi-organ failure. It is characterised by an uncontrolled immune response with massive neutrophil influx into peripheral organs. Neutrophil extravasation into tissues depends on actin remodeling and actin-binding proteins such as cortactin, which is expressed ubiquitously, except for neutrophils. Endothelial cortactin is necessary for proper regulation of neutrophil transendothelial migration and recruitment to sites of infection. We therefore hypothesised that cortactin plays a crucial role in sepsis development by regulating neutrophil trafficking. Using a murine model of sepsis induced by cecal ligation and puncture (CLP), we showed that cortactin-deficient (KO) mice survive better due to reduced lung injury. Histopathological analysis of lungs from septic KO mice revealed absence of oedema, reduced vascular congestion and mucus deposition, and better-preserved alveoli compared to septic wild-type (WT) mice. Additionally, sepsis-induced cytokine storm, excessive neutrophil infiltration into the lung and oxidative stress were significantly reduced in KO mice. Neutrophil depletion 12 h after sepsis improved survival in WT mice by averting lung injury, similar to both neutrophil-depleted and non-depleted KO mice. Our findings highlight a critical role of cortactin for lung neutrophil infiltration and sepsis severity.

HS1 deficiency protects against sepsis by attenuating neutrophil-inflicted lung damage.

Sepsis remains an important health problem worldwide due to inefficient treatments often resulting in multi-organ failure. Neutrophil recruitment is critical during sepsis. While neutrophils are required to combat invading bacteria, excessive neutrophil recruitment contributes to tissue damage due to their arsenal of molecular weapons that do not distinguish between host and pathogen. Thus, neutrophil recruitment needs to be fine-tuned to ensure bacterial killing, while avoiding neutrophil-inflicted tissue damage. We recently showed that the actin-binding protein HS1 promotes neutrophil extravasation; and hypothesized that HS1 is also a critical regulator of sepsis progression. We evaluated the role of HS1 in a model of lethal sepsis induced by cecal-ligation and puncture. We found that septic HS1-deficient mice had a better survival rate compared to WT mice due to absence of lung damage. Lungs of septic HS1-deficient mice showed less inflammation, fibrosis, and vascular congestion. Importantly, systemic CLP-induced neutrophil recruitment was attenuated in the lungs, the peritoneum and the cremaster in the absence of HS1. Lungs of HS1-deficient mice produced significantly more interleukin-10. Compared to WT neutrophils, those HS1-deficient neutrophils that reached the lungs had increased surface levels of Gr-1, ICAM-1, and L-selectin. Interestingly, HS1-deficient neutrophils had similar F-actin content and phagocytic activity, but they failed to polymerize actin and deform in response to CXCL-1 likely explaining the reduced systemic neutrophil recruitment in HS1-deficient mice. Our data show that HS1 deficiency protects against sepsis by attenuating neutrophil recruitment to amounts sufficient to combat bacterial infection, but insufficient to induce tissue damage.

ADAM17/MMP inhibition prevents neutrophilia and lung injury in a mouse model of COVID-19.

Severe coronavirus disease 2019 (COVID-19) is characterized by lung injury, cytokine storm, and increased neutrophil-to-lymphocyte ratio (NLR). Current therapies focus on reducing viral replication and inflammatory responses, but no specific treatment exists to prevent the development of severe COVID-19 in infected individuals. Angiotensin-converting enzyme-2 (ACE2) is the receptor for SARS-CoV-2, the virus causing COVID-19, but it is also critical for maintaining the correct functionality of lung epithelium and endothelium. Coronaviruses induce activation of a disintegrin and metalloprotease 17 (ADAM17) and shedding of ACE2 from the cell surface resulting in exacerbated inflammatory responses. Thus, we hypothesized that ADAM17 inhibition ameliorates COVID-19-related lung inflammation. We employed a preclinical mouse model using intratracheal instillation of a combination of polyinosinic:polycytidylic acid (poly(I:C)) and the receptor-binding domain of the SARS-CoV-2 spike protein (RBD-S) to mimic lung damage associated with COVID-19. Histologic analysis of inflamed mice confirmed the expected signs of lung injury including edema, fibrosis, vascular congestion, and leukocyte infiltration. Moreover, inflamed mice also showed an increased NLR as observed in critically ill COVID-19 patients. Administration of the ADAM17/MMP inhibitors apratastat and TMI-1 significantly improved lung histology and prevented leukocyte infiltration. Reduced leukocyte recruitment could be explained by reduced production of proinflammatory cytokines and lower levels of the endothelial adhesion molecules ICAM-1 and VCAM-1. Additionally, the NLR was significantly reduced by ADAM17/MMP inhibition. Thus, we propose inhibition of ADAM17/MMP as a novel promising treatment strategy in SARS-CoV-2-infected individuals to prevent the progression toward severe COVID-19.

The Arp2/3 Inhibitory Protein Arpin Is Required for Intestinal Epithelial Barrier Integrity.

The intestinal epithelial barrier (IEB) depends on stable interepithelial protein complexes such as tight junctions (TJ), adherens junctions (AJ), and the actin cytoskeleton. During inflammation, the IEB is compromised due to TJ protein internalization and actin remodeling. An important actin regulator is the actin-related protein 2/3 (Arp2/3) complex, which induces actin branching. Activation of Arp2/3 by nucleation-promoting factors is required for the formation of epithelial monolayers, but little is known about the relevance of Arp2/3 inhibition and endogenous Arp2/3 inhibitory proteins for IEB regulation. We found that the recently identified Arp2/3 inhibitory protein arpin was strongly expressed in intestinal epithelial cells. Arpin expression decreased in response to tumor necrosis factor (TNF)α and interferon (IFN)γ treatment, whereas the expression of gadkin and protein interacting with protein C-kinase α-subunit 1 (PICK1), other Arp2/3 inhibitors, remained unchanged. Of note, arpin coprecipitated with the TJ proteins occludin and claudin-1 and the AJ protein E-cadherin. Arpin depletion altered the architecture of both AJ and TJ, increased actin filament content and actomyosin contractility, and significantly increased epithelial permeability, demonstrating that arpin is indeed required for maintaining IEB integrity. During experimental colitis in mice, arpin expression was also decreased. Analyzing colon tissues from ulcerative colitis patients by Western blot, we found different arpin levels with overall no significant changes. However, in acutely inflamed areas, arpin was significantly reduced compared to non-inflamed areas. Importantly, patients receiving mesalazine had significantly higher arpin levels than untreated patients. As arpin depletion (theoretically meaning more active Arp2/3) increased permeability, we wanted to know whether Arp2/3 inhibition would show the opposite. Indeed, the specific Arp2/3 inhibitor CK666 ameliorated TNFα/IFNγ-induced permeability in established Caco-2 monolayers by preventing TJ disruption. CK666 treatment also attenuated colitis development, colon tissue damage, TJ disruption, and permeability in dextran sulphate sodium (DSS)-treated mice. Our results demonstrate that loss of arpin triggers IEB dysfunction during inflammation and that low arpin levels can be considered a novel hallmark of acute inflammation.

Intermittent rolling is a defect of the extravasation cascade caused by Myosin1e-deficiency in neutrophils.

Neutrophil extravasation is a migratory event in response to inflammation that depends on cytoskeletal dynamics regulated by myosins. Myosin-1e (Myo1e) is a long-tailed class-I myosin that has not yet been studied in the context of neutrophil-endothelial interactions and neutrophil extravasation. Intravital microscopy of TNFα-inflamed cremaster muscles in Myo1e-deficient mice revealed that Myo1e is required for efficient neutrophil extravasation. Specifically, Myo1e deficiency caused increased rolling velocity, decreased firm adhesion, aberrant crawling, and strongly reduced transmigration. Interestingly, we observed a striking discontinuous rolling behavior termed "intermittent rolling," during which Myo1e-deficient neutrophils showed alternating rolling and jumping movements. Surprisingly, chimeric mice revealed that these effects were due to Myo1e deficiency in leukocytes. Vascular permeability was not significantly altered in Myo1e KO mice. Myo1e-deficient neutrophils showed diminished arrest, spreading, uropod formation, and chemotaxis due to defective actin polymerization and integrin activation. In conclusion, Myo1e critically regulates adhesive interactions of neutrophils with the vascular endothelium and neutrophil extravasation. Myo1e may therefore be an interesting target in chronic inflammatory diseases characterized by excessive neutrophil recruitment.

Beneficial effects of nutritional supplements on intestinal epithelial barrier functions in experimental colitis models in vivo.

Acute and chronic colitis affect a huge proportion of the population world-wide. The etiology of colitis cases can be manifold, and diet can significantly affect onset and outcome of colitis. While many forms of acute colitis are easily treatable, chronic forms of colitis such as ulcerative colitis and Crohn's disease (summarized as inflammatory bowel diseases) are multifactorial with poorly understood pathogenesis. Inflammatory bowel diseases are characterized by exacerbated immune responses causing epithelial dysfunction and bacterial translocation. There is no cure and therapies aim at reducing inflammation and restoring intestinal barrier function. Unfortunately, most drugs can have severe side effects. Changes in diet and inclusion of nutritional supplements have been extensively studied in cell culture and animal models, and some supplements have shown promising results in clinical studies. Most of these nutritional supplements including vitamins, fatty acids and phytochemicals reduce oxidative stress and inflammation and have shown beneficial effects during experimental colitis in rodents induced by dextran sulphate sodium or 2,4,6-trinitrobenzene sulfonic acid, which remain the gold standard in pre-clinical colitis research. Here, we summarize the mechanisms through which such nutritional supplements contribute to epithelial barrier stabilization.

Role of sodium/glucose cotransporter inhibition on a rat model of angiotensin II-dependent kidney damage.

BACKGROUND: Renal proximal tubular sodium and glucose reabsorption are regulated by the sodium-glucose cotransporter (SGLT2). Changes in this transporter can play a role in hyperglycaemia and reactive oxygen species (ROS) production. We demonstrated increased glucose absorption in proximal tubule membrane vesicles and increased expression of SGLT2 in hypertensive rats. Here we investigated Angiotensin II (Ang II) -dependent SGLT2 expression induction and the role of SGLT2 induction in the development of Ang II-dependent kidney damage. The aim of this study was to determine whether SGLT2 induction by Ang II is associated with Ang II-dependent kidney damage. We propose the following objectives a) to demonstrate that Ang II induces SGLT2 expression and b) to demonstrate that prevention of SGLT2 expression and activity prevent Ang II-induced kidney damage. METHODS: We used chronic Ang II infusion as a model of kidney damage in male Wistar rats and evaluated systolic blood pressure by telemetric methods. SGLT2 mRNA and protein expression were evaluated by PCR and immunoblotting. SGLT2 activity was evaluated in brush border membrane vesicles by measuring glucose uptake. ROS production was measured by confocal microscopy. The glomerular filtration rate (GFR) was evaluated by the inulin excretion method, and urinary protein excretion was evaluated by the Bradford method. Biological parameter evaluations were performed, after two weeks of infusion of Ang II. We compared the effects of Angiotensin II (AT1) receptor blockade by Losartan and SGLT2 inhibition by Empagliflozin both as monotherapy treatments and in combination on the development of kidney damage. RESULTS: Chronic Ang II infusion led to a blood pressure elevation and increased SGLT2 mRNA expression and activity as well as kidney damage, as reflected by increased ROS production, decreased GFR and increased urinary protein excretion. AT1 receptor blockade prevented all these changes. By contrast, SGLT2 inhibition did not affect blood pressure and had a small effect on kidney damage. However, the combination of both drugs resulted in the potentiation of the effects observed by AT1 receptor blockade alone. CONCLUSIONS: We suggest that Ang II-dependent increased SGLT2 induction is one mechanism by which Ang II induces kidney damage.

Role of Src and Cortactin in Pemphigus Skin Blistering.

Autoantibodies against desmoglein (Dsg) 1 and Dsg3 primarily cause blister formation in the autoimmune disease pemphigus vulgaris (PV). Src was proposed to contribute to loss of keratinocyte cohesion. However, the role and underlying mechanisms are unclear and were studied here. In keratinocytes, cell cohesion in response to autoantibodies was reduced in Src-dependent manner by two patient-derived PV-IgG fractions as well as by AK23 but not by a third PV-IgG fraction, although Src was activated by all autoantibodies. Loss of cell cohesion was progredient in a timeframe of 24 h and AK23, similar to PV-IgG, interfered with reconstitution of cell cohesion after Ca2+-switch, indicating that the autoantibodies also interfered with desmosome assembly. Dsg3 co-localized along cell contacts and interacted with the Src substrate cortactin. In keratinocytes isolated from cortactin-deficient mice, cell adhesion was impaired and Src-mediated inhibition of AK23-induced loss of cell cohesion for 24 h was significantly reduced compared to wild-type (wt) cells. Similarly, AK23 impaired reconstitution of cell adhesion was Src-dependent only in the presence of cortactin. Likewise, Src inhibition significantly reduced AK23-induced skin blistering in wt but not cortactin-deficient mice. These data suggest that the Src-mediated long-term effects of AK23 on loss of cell cohesion and skin blistering are dependent on cortactin-mediated desmosome assembly. However, in human epidermis PV-IgG-induced skin blistering and ultrastructural alterations of desmosomes were not affected by Src inhibition, indicating that Src may not be critical for skin blistering in intact human skin, at least when high levels of autoantibodies targeting Dsg1 are present.

Comparative effects of nitric oxide dependent and independent vasodilation on impaired hindlimb revascularization in eNOS-/- mice.

Ischemia due to vascular occlusion induces vasodilation as an initial response, followed by arteriogenesis or angiogenesis. Vasodilation through nitric oxide (NO) independent and dependent mechanisms may be sufficient to restore the altered neovascularization in pathological situations where the NO is altered. Using a posterior limb claudication model to evaluate ischemia-induced revascularization in eNOS-/- mice, we compared the effects of sodium nitrite, a NO-dependent vasodilator, and prazocin, an alpha-adrenergic blocker and NO-independent vasodilator, on hindlimb revascularization. We evaluated the blood flow of the hindlimbs, NO and nitrites metabolites, the expression of tissue endothelial cell markers and proangiogenic factors, as well as the gait locomotion. Our results suggest that the use of a peripheral vasodilator can substitute the initial absence of NO as an endogenous vasodilator. However, final resolution of the ischemic process requires a NO-mediated pathway, which through changes in vascular hemodynamics, promotes the generation of angiogenic messengers facilitating the functional recovery of the damaged limb.

Homoectoine Protects Against Colitis by Preventing a Claudin Switch in Epithelial Tight Junctions.

BACKGROUND: Inflammatory bowel diseases (IBD) are multifactorial disorders affecting millions of people worldwide with alarmingly increasing incidences every year. Dysfunction of the intestinal epithelial barrier is associated with IBD pathogenesis, and therapies include anti-inflammatory drugs that enhance intestinal barrier function. However, these drugs often have adverse side effects thus warranting the search for alternatives. Compatible solutes such as bacterial ectoines stabilize cell membranes and proteins. AIM: To unravel whether ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) and homoectoine (4,5,6,7-tetrahydro-2-methyl-1H-(1,3)-diazepine-4-carboxylic acid), a synthetic derivative of ectoine, have beneficial effects during dextran sulfate sodium (DSS)-induced colitis in mice. METHODS/RESULTS: We found that the disease activity index was significantly reduced by both ectoines. DSS-induced edema formation, epithelial permeability, leukocyte recruitment and tissue damage were reduced by ectoine and homoectoine, with the latter having stronger effects. Interestingly, the claudin switch usually observed during colitis (decreased expression of claudin-1 and increased expression of the leaky claudin-2) was completely prevented by homoectoine, whereas ectoine only reduced claudin-2 expression. Concomitantly, only homoectoine ameliorated the drop in transepithelial electrical resistance induced by IFN-γ and TNF-α in Caco-2 cells. Both ectoines inhibited loss of ZO-1 and occludin and prevented IFN-γ/TNF-α-induced increased paracellular flux of 4 kDa FITC-dextran in vitro. Moreover, both ectoines reduced expression of pro-inflammatory cytokines and oxidative stress during colitis. CONCLUSION: While both ectoine and homoectoine have protective effects on the epithelial barrier during inflammation, only homoectoine completely prevented the inflammatory claudin switch in tight junctions. Thus, homoectoine may serve as diet supplement in IBD patients to reach or extend remission.

Androgens Mediate ß-adrenergic Vasorelaxation Impairment Using Adenylyl Cyclase.

Cardiovascular disease development has been associated with sex differences, suggesting that sex hormones are implicated in vascular function and development of hypertension. Vascular tone comparison at different stages of rat growth represents a good model to study testosterone-related vascular response. We explored the role of testosterone in modulation of age-dependent impaired ß-adrenergic vasodilation. The 3-week-old male Sprague-Dawley rats were sorted in 3-week-old rats without any manipulation and 3-week-old rats treated with testosterone. The 9-week-old rats were randomly grouped into 9-week-old rats without any manipulation (sham), 9-week-old rats that underwent gonadectomy (9-week-old castrated), and 9-week-old castrated treated with testosterone replacement therapy (9-week-old castrated + testosterone). Vascular relaxation was evaluated in aortic rings. ß-adrenergic receptor protein expression, cyclic adenosine monophosphate production, testosterone levels, and adenylyl cyclase (AC) gene expression were assessed. Testosterone levels were low in 3-week-old and 9-week-old castrated rats compared with 9-week-old sham rats. Testosterone replacement raised these levels in 3-week-old and 9-week-old castrated rats similar to those of 9-week-old sham rats. SQ22536, the AC inhibitor, prevented isoproterenol-induced relaxation in aortic rings from 3-week-old and 9-week-old castrated rats. The ß-adrenergic receptor protein expression was similar in all experimental groups. AC mRNA and protein expression and cyclic adenosine monophosphate levels were elevated in 3-week-old and 9-week-old castrated rats compared with 3-week-old + testosterone, 9-week-old sham, and 9-week-old castrated + testosterone rats. In conclusion, we demonstrated that age maturation was associated with vascular relaxation impairment. Variations in testosterone levels and reduced AC expression may be responsible for this altered vascular function.

Analyzing Beneficial Effects of Nutritional Supplements on Intestinal Epithelial Barrier Functions During Experimental Colitis.

Inflammatory bowel diseases (IBD), including Crohn's disease and ulcerative colitis, are chronic relapsing disorders of the intestines. They cause severe problems, such as abdominal cramping, bloody diarrhea, and weight loss, in affected individuals. Unfortunately, there is no cure yet, and treatments only aim to alleviate symptoms. Current treatments include anti-inflammatory and immunosuppressive drugs that may cause severe side effects. This warrants the search for alternative treatment options, such as nutritional supplements, that do not cause side effects. Before their application in clinical studies, such compounds must be rigorously tested for effectiveness and security in animal models. A reliable experimental model is the dextran sulfate sodium (DSS) colitis model in mice, which reproduces many of the clinical signs of ulcerative colitis in humans. We recently applied this model to test the beneficial effects of a nutritional supplement containing vitamins C and E, L-arginine, and ω3-polyunsaturated fatty acids (PUFA). We analyzed various disease parameters and found that this supplement was able to ameliorate edema formation, tissue damage, leukocyte infiltration, oxidative stress, and the production of pro-inflammatory cytokines, leading to an overall improvement in the disease activity index. In this article, we explain in detail the correct application of nutritional supplements using the DSS colitis model in C57Bl/6 mice, as well as how disease parameters such as histology, oxidative stress, and inflammation are assessed. Analyzing the beneficial effects of different diet supplements may then eventually open new avenues for the development of alternative treatment strategies that alleviate IBD symptoms and/or that prolong the phases of remission without causing severe side effects.

Loss of cortactin causes endothelial barrier dysfunction via disturbed adrenomedullin secretion and actomyosin contractility.

Changes in vascular permeability occur during inflammation and the actin cytoskeleton plays a crucial role in regulating endothelial cell contacts and permeability. We demonstrated recently that the actin-binding protein cortactin regulates vascular permeability via Rap1. However, it is unknown if the actin cytoskeleton contributes to increased vascular permeability without cortactin. As we consistently observed more actin fibres in cortactin-depleted endothelial cells, we hypothesised that cortactin depletion results in increased stress fibre contractility and endothelial barrier destabilisation. Analysing the contractile machinery, we found increased ROCK1 protein levels in cortactin-depleted endothelium. Concomitantly, myosin light chain phosphorylation was increased while cofilin, mDia and ERM were unaffected. Secretion of the barrier-stabilising hormone adrenomedullin, which activates Rap1 and counteracts actomyosin contractility, was reduced in plasma from cortactin-deficient mice and in supernatants of cortactin-depleted endothelium. Importantly, adrenomedullin administration and ROCK1 inhibition reduced actomyosin contractility and rescued the effect on permeability provoked by cortactin deficiency in vitro and in vivo. Our data suggest a new role for cortactin in controlling actomyosin contractility with consequences for endothelial barrier integrity.

Experimental Colitis Is Attenuated by Cardioprotective Diet Supplementation That Reduces Oxidative Stress, Inflammation, and Mucosal Damage.

Inflammatory bowel diseases (IBD) such as ulcerative colitis (UC) and Crohn's disease (CD) are multifactorial, relapsing disorders of the gastrointestinal tract. However, the etiology is still poorly understood but involves altered immune responses, epithelial dysfunction, environmental factors, and nutrition. Recently, we have shown that the diet supplement corabion has cardioprotective effects due to reduction of oxidative stress and inflammation. Since oxidative stress and inflammation are also prominent risk factors in IBD, we speculated that corabion also has beneficial effects on experimental colitis. Colitis was induced in male mice by administration of 3.5% (w/v) dextran sulfate sodium (DSS) in drinking water for a period of 3 or 7 days with or without daily gavage feeding of corabion consisting of vitamin C, vitamin E, L-arginine, and eicosapentaenoic and docosahexaenoic acid. We found that corabion administration attenuated DSS-induced colon shortening, tissue damage, and disease activity index during the onset of colitis. Mechanistically, these effects could be explained by reduced neutrophil recruitment, oxidative stress, production of proinflammatory cytokines, and internalization of the junctional proteins ZO-1 and E-cadherin leading to less edema formation. Thus, corabion may be a useful diet supplement for the management of chronic inflammatory intestinal disorders such as IBD.

Correlación entre el indiceadiponectina/resistina y albuminuria enpacientes diabéticos tipo 2 hipertensos / Correlation between the adiponectin/resistin index and albuminuria in hypertensive type 2 diabetic patients

Evaluar si hay correlación entre los niveles de adipocitocinas, el índice A/R,con la albuminuria en pacientes diabéticos tipo 2 hipertensos (DM2HTA). Material y Método: se incluyeron 30 pacientes DM2HTA, sin tratamiento antihipertensivo previo, en quienes los niveles de adipokinas fueron medidos por duplicado mediante ELISA(R&D Systems, Minneapolis, MN), en todos ellos de determinó albuminuria de 24 horas por nefelometría. El índice A/R se determinó mediante la fórmula (1+log10 Resistinalog10 Adiponectina), como fue descrito. La relación entre los niveles de adipokinas y del índice A/R con la albuminuria se determinó con el coeficiente de correlación de Pearson. Resultados: no se encontró correlación entre los niveles de adiponectina y el grado de albuminuria (R= -0,09, p > 0,05), ni con los de resistina (R= 0,23 p>0,05),sin embargo encontramos una correlación significativa entre el índice A/R (R= 0,312,p<0,01) y la presencia de albumina en orina de 24 horas. Conclusión: los resultados muestran una mayor asociación del índice A/R con daño renal en el paciente hipertenso con DM2 que los niveles de adipokinas, por lo que puede ser un marcador de riesgo de nefropatía, y a su vez un blanco terapéutico...

Oxidative Stress-Dependent Coronary Endothelial Dysfunction in Obese Mice.

Obesity is involved in several cardiovascular diseases including coronary artery disease and endothelial dysfunction. Endothelial Endothelium vasodilator and vasoconstrictor agonists play a key role in regulation of vascular tone. In this study, we evaluated coronary vascular response in an 8 weeks diet-induced obese C57BL/6 mice model. Coronary perfusion pressure in response to acetylcholine in isolated hearts from obese mice showed increased vasoconstriction and reduced vasodilation responses compared with control mice. Vascular nitric oxide assessed in situ with DAF-2 DA showed diminished levels in coronary arteries from obese mice in both basal and acetylcholine-stimulated conditions. Also, released prostacyclin was decreased in heart perfusates from obese mice, along with plasma tetrahydrobiopterin level and endothelium nitric oxide synthase dimer/monomer ratio. Obesity increased thromboxane A2 synthesis and oxidative stress evaluated by superoxide and peroxynitrite levels, compared with control mice. Obese mice treated with apocynin, a NADPH oxidase inhibitor, reversed all parameters to normal levels. These results suggest that after 8 weeks on a high-fat diet, the increase in oxidative stress lead to imbalance in vasoactive substances and consequently to endothelial dysfunction in coronary arteries.

Antioxidative diet supplementation reverses high-fat diet-induced increases of cardiovascular risk factors in mice.

Obesity is a worldwide epidemic that is characterized not only by excessive fat deposition but also by systemic microinflammation, high oxidative stress, and increased cardiovascular risk factors. While diets enriched in natural antioxidants showed beneficial effects on oxidative stress, blood pressure, and serum lipid composition, diet supplementation with synthetic antioxidants showed contradictive results. Thus, we tested in C57Bl/6 mice whether a daily dosage of an antioxidative mixture consisting of vitamin C, vitamin E, L-arginine, eicosapentaenoic acid, and docosahexaenoic acid (corabion) would affect cardiovascular risk factors associated with obesity. Obese mice showed increased serum triglyceride and glucose levels and hypertension after eight weeks of being fed a high-fat diet (HFD). Importantly, corabion ameliorated all of these symptoms significantly. Oxidative stress and early signs of systemic microinflammation already developed after two weeks of high-fat diet and were significantly reduced by daily doses of corabion. Of note, the beneficial effects of corabion could not be observed when applying its single antioxidative components suggesting that a combination of various nutrients is required to counteract HFD-induced cardiovascular risk factors. Thus, daily consumption of corabion may be beneficial for the management of obesity-related cardiovascular complications.