Renin-angiotensin system and inflammation update.

The most classical view of the renin-angiotensin system (RAS) emphasizes its role as an endocrine regulator of sodium balance and blood pressure. However, it has long become clear that the RAS has pleiotropic actions that contribute to organ damage, including modulation of inflammation. Angiotensin II (Ang II) activates angiotensin type 1 receptors (AT1R) to promote an inflammatory response and organ damage. This represents the pathophysiological basis for the successful use of RAS blockers to prevent and treat kidney and heart disease. However, other RAS components could have a built-in capacity to brake proinflammatory responses. Angiotensin type 2 receptor (AT2R) activation can oppose AT1R actions, such as vasodilatation, but its involvement in modulation of inflammation has not been conclusively proven. Angiotensin-converting enzyme 2 (ACE2) can process Ang II to generate angiotensin-(1-7) (Ang-(1-7)), that activates the Mas receptor to exert predominantly anti-inflammatory responses depending on the context. We now review recent advances in the understanding of the interaction of the RAS with inflammation. Specific topics in which novel information became available recently include intracellular angiotensin receptors; AT1R posttranslational modifications by tissue transglutaminase (TG2) and anti-AT1R autoimmunity; RAS modulation of lymphoid vessels and T lymphocyte responses, especially of Th17 and Treg responses; interactions with toll-like receptors (TLRs), programmed necrosis, and regulation of epigenetic modulators (e.g. microRNAs and bromodomain and extraterminal domain (BET) proteins). We additionally discuss an often overlooked effect of the RAS on inflammation which is the downregulation of anti-inflammatory factors such as klotho, peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α), transient receptor potential ankyrin 1 (TRPA1), SNF-related serine/threonine-protein kinase (SNRK), serine/threonine-protein phosphatase 6 catalytic subunit (Ppp6C) and n-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP). Both transcription factors, such as nuclear factor κB (NF-κB), and epigenetic regulators, such as miRNAs are involved in downmodulation of anti-inflammatory responses. A detailed analysis of pathways and targets for downmodulation of anti-inflammatory responses constitutes a novel frontier in RAS research.

Aldosterone, Inflammation, Immune System, and Hypertension.

Aldosterone is a mineralocorticoid hormone that controls body fluid and electrolyte balance. Excess aldosterone is associated with cardiovascular and metabolic diseases. Inflammation plays a critical role on vascular damage promoted by aldosterone and aggravates vascular abnormalities, including endothelial dysfunction, vascular remodeling, fibrosis and oxidative stress, and other manifestations of end-organ damage that are associated with hypertension, other forms of cardiovascular disease, and diabetes mellitus and the metabolic syndrome. Over the past few years, many studies have consistently shown that aldosterone activates cells of the innate and adaptive immune systems. Macrophages and T cells accumulate in the kidneys, heart, and vasculature in response to aldosterone, and infiltration of immune cells contributes to end-organ damage in cardiovascular and metabolic diseases. Aldosterone activates various subsets of innate immune cells such as dendritic cells and monocytes/macrophages, as well as adaptive immune cells such as T lymphocytes, and, by activation of mineralocorticoid receptors stimulates proinflammatory transcription factors and the production of adhesion molecules and inflammatory cytokines and chemokines. This review will briefly highlight some of the studies on the involvement of aldosterone in activation of innate and adaptive immune cells and its impact on the cardiovascular system. Since aldosterone plays a key role in many cardiovascular and metabolic diseases, these data will open up promising perspectives for the identification of novel biomarkers and therapeutic targets for prevention and treatment of diseases associated with increased levels of aldosterone, such as arterial hypertension, obesity, the metabolic syndrome, and heart failure.

Water balance of lung and nitrogen oxide in blood at experimental autoimmune encephalomyelitis after capsaicin blockade of vagus nerve.

The purpose of the research: To study the water balance of lung and NO level in blood in experimental autoimmune encephalomyelitis combined with capsaicin blockade of vagus nerve. Methods: Experiments were conducted on 47 adult (16-week-old) male rats weighing 220-280 g. To simulate the experimental autoimmune encephalomyelitis (EAE) rats were subcutaneously injected with encephalitogenic mixture in complete Freund's adjuvant (0.2 ml; the content of inactivated Mycobacterium tuberculosis was 5 mg/ml) at the rate of 100 mg of homologous spinal cord homogenate per animal. Сapsaicin blockade was performed by bilateral application of 50 uM capsaicin («Sigma¼) on the neck portions of vagus nerves. The animals were divided into 4 groups: intact rats - control group1; rats with EAE; rats with capsaicin application on vagus nerve + EAE; sham operated rats subjected to vagus nerves allocation without the subsequent capsaicin application + EAE - control group 2. The next parameters were detected: the content of nitric oxide in blood plasma; protein content in broncho-alveolar lavage fluid; lung water balance indices including the amount of total, extra- and intravascular fluid and blood supply of lungs, which were calculated based on wet and dry lung mass and the hemoglobin content in blood and lung tissue determined by hemiglobincyanide method. Results: It was found that EAE is accompanied by an increase of total fluid, extravascular fluid (EVF) and blood supply of lungs on the background of increasing content of nitric oxide in arterial (art) and venous (ven) blood. In EAE and its combination with bilateral capsaicin blockade of vagus nerve a strong negative correlation between the NOart / NOven coefficient and EVF amount was found out. The blockade of capsaicin-sensitive vagal afferents normalized lung water balance impaired in EAE and restored the levels of nitric oxide in blood plasma. Conclusion: The obtained results suggest that capsaicin-sensitive vagal afferents with NO-ergic mechanisms involvment take part in the development of pulmonary hyperhydration during experimental autoimmune encephalomyelitis.

Oral intoxication of mice with Shiga toxin type 2a (Stx2a) and protection by anti-Stx2a monoclonal antibody 11E10.

Shiga toxin (Stx)-producing Escherichia coli (STEC) strains cause food-borne outbreaks of hemorrhagic colitis and, less commonly, a serious kidney-damaging sequela called the hemolytic uremic syndrome (HUS). Stx, the primary virulence factor expressed by STEC, is an AB5 toxin with two antigenically distinct forms, Stx1a and Stx2a. Although both toxins have similar biological activities, Stx2a is more frequently produced by STEC strains that cause HUS than is Stx1a. Here we asked whether Stx1a and Stx2a act differently when delivered orally by gavage. We found that Stx2a had a 50% lethal dose (LD50) of 2.9 µg, but no morbidity occurred after oral intoxication with up to 157 µg of Stx1a. We also compared several biochemical and histological parameters in mice intoxicated orally versus intraperitoneally with Stx2a. We discovered that both intoxication routes caused similar increases in serum creatinine and blood urea nitrogen, indicative of kidney damage, as well as electrolyte imbalances and weight loss in the animals. Furthermore, kidney sections from Stx2a-intoxicated mice revealed multifocal, acute tubular necrosis (ATN). Of particular note, we detected Stx2a in kidney sections from orally intoxicated mice in the same region as the epithelial cell type in which ATN was detected. Lastly, we showed reduced renal damage, as determined by renal biomarkers and histopathology, and full protection of orally intoxicated mice with monoclonal antibody (MAb) 11E10 directed against the toxin A subunit; conversely, an irrelevant MAb had no therapeutic effect. Orally intoxicated mice could be rescued by MAb 11E10 6 h but not 24 h after Stx2a delivery.

Hidratación en el transoperatorio del recién nacido quirúrgico: diez años de experiencia / Hydration during surgical procedures in newborn: ten years of experience

Evaluar la utilización de la hidratación por el método de Berry modificado, en el transoperatorio de los recién nacidos que fueron sometidos a intervenciones quírurgicas desde enero de 1990 a diciembre de 2000. Estudio retrospéctivo, descriptivo de 525 recién nacidos, que ingresaron al Servicio de Cirugía Neonatal de la Maternidad "Concepción Palacios" y que requirieron intervención quirúrgica; en 426 de ellos, se utilizó la hidratación. Servicio de Cirugía Neonatal Departamento de Pediatría Maternidad "Concepción Palacios". Caracas. Los valores metabólicos y electrolíticos, determinados en el posoperatorio inmediato, en los 426 pacientes donde se utilizó la hidratación en estudio se mantuvieron estables. la glicemia fue normal en el 93.90 por ciento de los casos, al igual que el calcio en 96,60 por ciento, el fósforo en 99 por ciento, el sodio en 98,60 por ciento, y el potasio en 98,13 por ciento. El grupo que no recibió hidratación presentó importantes trastornos electrolíticos y metabólicos. El esquema de Berry modificado, utilizado en el transoperatorio, evita complicaciones posoperatorias debido a que logra dar estabilidad hidroelectrolítica y metabólica en el recién nacido quirúrgico

Total lymphocyte count in peripheral blood of peritoneal dialysis patients: relationship to clinical parameters and outcome.

BACKGROUND: Total lymphocyte count (TLC) is used as a nutritional status measurement. The impact of TLC on mortality in peritoneal dialysis (PD) patients is controversial. This study aimed at evaluating the effect of TLC on mortality, and assessing the relationship between TLC and nutritional status, anemia and erythropoietin (EPO) response, acute-phase response, dialysis adequacy and volume status in PD patients. METHODS: Seventy-three PD patients were monitored for 3 yrs from the beginning of the treatment. Data recorded for each patient included demographic features, comorbidity, TLC, blood biochemistry, systolic and diastolic blood pressures (BP), indices of dialysis adequacy and nutritional status, total fluid removal and mortality. Adjusted mortality risk for TLC was estimated using the Cox's regression models composed by TLC and one covariate having a value p<0.05 in univariate analysis. RESULTS: The 3-yr patient survival rates were significantly different among the TLC quartiles. The adjusted TLC was found, generally, to be a significant predictor of death in reduced Cox's models, except in models composed of TLC and total fluid removal or serum albumin. The receiver operating characteristics (ROC) analysis demonstrated that TLC provided a significant prediction of mortality. TLC correlated positively to total fluid removal, serum albumin, triglyceride and hematocrit, and negatively correlated to BP, high peritoneal transport and EPO-need. It did not correlate to other measures of nutritional status, dialysis adequacy and acute-phase response. Fluid removal and serum triglyceride were independent predictors of TLC in multivariate analysis. CONCLUSIONS: Our findings suggest that TLC can be used as a simple prognostic tool in PD patients; however, the association between TLC and mortality is confounded by other prognostic factors. Volume status could be a more important factor affecting the TLC than nutritional status.

Antisperm antibodies modify plasma membrane functional integrity and inhibit osmosensitive calcium influx in human sperm.

BACKGROUND: The hypo-osmotic swelling (HOS) test evaluates the ability of the functional sperm plasma membrane to stretch following cell swelling when exposed to hypo-osmotic solutions. Sperm samples with low HOS scores show low fertilization and pregnancy rates during assisted reproductive techniques, though data are controversial. The aim of this study was to compare the results of the HOS test in a group of normozoospermic men with those in a group of subjects affected by autoimmune infertility due to the presence of antisperm antibodies (ASA) bound to the sperm surface. METHODS: Sperm from normozoospermic and from infertile subjects affected by autoimmune infertility were exposed to hypo-osmolar conditions to verify the effects on intracellular calcium concentrations and acrosome reaction. RESULTS: Sperm samples from infertile men with ASA showed HOS test scores that were significantly lower than those of normozoospermic subjects despite similar sperm viability percentages. Sperm with ASA bound to their plasma membrane showed a reduced rise in intracellular calcium concentrations and acrosome reaction after hypo-osmotic challenge with respect to sperm from normozoospermic subjects without ASA. CONCLUSIONS: Infertile subjects with ASA have a reduced sperm plasma membrane functional integrity that could explain, at least in part, the low fertilization and pregnancy rates observed in these subjects during assisted reproductive procedures. Evaluation for the presence of ASA in all sperm samples showing low HOS test scores in the presence of normal sperm viability percentages is suggested.

Effect of head-down tilt bedrest (10 days) on lymphocyte reactivity.

Immunological responses of six healthy males to 10 days of head-down tilt bedrest (HDT) were assessed. Lymphocyte responsiveness was severely reduced immediately before, during, and immediately after the HDT, even though the lymphocyte numbers did not change. By contrast, delayed-type hypersensitivity was not affected. No dramatic changes were found in WBC counts and lymphocyte subpopulations, with the only exception of natural killer (NK) cells which transiently decreased immediately after HDT. Plasma cortisol levels were elevated above normal immediately before and during the HDT. The data suggest that the mitogenic response of lymphocytes was affected by psychological and fluid shift stress. These results are compared with data obtained during and after spaceflight. We conclude that the stress of HDT induces changes in immunological responsiveness that are strikingly similar to those arising from the stress of spaceflight.