angiotensin-i and Sepsis

Sepsis can lead to shock, multiple organ failure, and even death. Platelets play an active role in the pathogenesis of sepsis-induced multiple organ failure. Angiotensin (Ang)-(1-7), a biologically active peptide, counteracts various effects of Ang II and attenuates inflammatory responses, reactive oxygen species production, and apoptosis. We evaluated the effects of Ang-(1-7) on organ injury and platelet dysfunction in rats with endotoxaemia. We treated male Wistar rats with saline or lipopolysaccharide (LPS, 10 mg, intravenously) then Ang-(1-7) (1 mg/kg, intravenous infusion for 3 h beginning 30 min after LPS administration). We analysed several haemodynamic, biochemical, and inflammatory parameters, as well as platelet counts and aggregation. Ang-(1-7) improved hypotension and organ dysfunction, and attenuated plasma interleukin-6, chemokines and nitric oxide production in rats after LPS administration. The LPS-induced reduction in platelet aggregation, but not the decreased platelet count, was restored after Ang-(1-7) treatment. The protein expression of iNOS and IκB, but not phosphorylated ERK1/2 and p38, was diminished in Ang-(1-7)-treated LPS rats. The histological changes in liver and lung were significantly attenuated in Ang-(1-7)-treated LPS rats. Our results suggest that Ang-(1-7) ameliorates endotoxaemic-induced organ injury and platelet dysfunction, likely through the inhibition of the inflammatory response and nitric oxide production.

Topics: Angiotensin I; Animals; Blood Platelets; Endotoxemia; Hypotension; Interleukin-6; Lipopolysaccharides; Male; Multiple Organ Failure; Peptide Fragments; Rats; Rats, Wistar; Sepsis; Vasodilator Agents

Sepsis-induced myocardial dysfunction is a major cause of death. The present study explored whether angiotensin (Ang)-(1-7), an important biologically active peptide of the renin-angiotensin system, could improve cardiac dysfunction and attenuate inflammation and apoptosis. Experiments were carried out in mice and in neonatal rat cardiomyocytes (NRCMs) treated with lipopolysaccharide (LPS) or Ang-(1-7). Angiotensin converting enzyme 2 (ACE2), Ang-(1-7) and Mas receptor (MasR) expressions were reduced in the mouse left ventricular and NRCM treated with LPS. Ang-(1-7) increased the ejection fraction and fractional shortening of left ventricular, which were reduced upon LPS injection in mice. Ang-(1-7) pre-treatment reversed LPS-induced decreases of α-myosin heavy chain (MHC) and β-MHC, and increases of S100 calcium binding protein A8 (S100A8) and S100A9 in the mouse left ventricular. The LPS-induced increases of tumor necrosis factor (TNF)-α and interleukin (IL)-1β in the mouse left ventricular and NRCMs were inhibited by Ang-(1-7) administration. Ang-(1-7) treatment reversed the increases of cleaved-caspase 3, cleaved-caspase 8 and Bax, and the decrease of Bcl2 induced by LPS in the mouse left ventricular and NRCMs. The increases of MAPKs pathway induced by LPS in NRCMs were inhibited by Ang-(1-7). These results indicate that Ang-(1-7) protects against sepsis-associated left ventricular dysfunction induced by LPS, and increases cardiac contractility via attenuating inflammation and apoptosis.

Topics: Angiotensin I; Angiotensin-Converting Enzyme 2; Animals; Apoptosis; Cardiotonic Agents; Cells, Cultured; Inflammation; Lipopolysaccharides; Male; Mice, Inbred C57BL; Myocytes, Cardiac; Nerve Tissue Proteins; Peptide Fragments; Proto-Oncogene Mas; Rats, Sprague-Dawley; Receptors, G-Protein-Coupled; Sepsis; Ventricular Dysfunction, Left

Sepsis is a frequent cause of kidney injury. The present study investigated whether Alamandine (Ala) could alleviate sepsis-associated renal injury by reducing inflammation and apoptosis. In addition, we investigated downstream signaling pathways modulated by Ala. Studies were performed in mice treated with lipopolysaccharide (LPS) and in the human proximal tubular epithelial cell line HK-2. The increase in serum creatinine, blood urea nitrogen, cystatin C and Fg, and neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 in the kidneys of mice treated with LPS were reduced after administration of Ala. Exposure to LPS increased interleukin-1 beta (IL-1β), IL-6, and tumor necrosis factor alpha (TNF-α) in mice and HK-2 cells, but were reduced after Ala treatment. Furthermore, increased levels of cleaved caspase 3, cleaved caspase 7, cleaved caspase 9, cleaved poly (ADP-ribose) polymerase (PARP) and Bax and reduced levels of Bcl2 in LPS-treated mice and HK-2 cells were reversed after Ala administration. In addition, LPS increased the levels of p-PI3K/PI3K, p-Akt/Akt, p-ERK/ERK, p-JNK/JNK, p-p38/p38 and p-FoxO1 in HK-2 cells, and all were reversed after Ala administration. These results indicate that Ala could improve renal function and inhibit inflammation and apoptosis in LPS induced sepsis mouse models. We demonstrated that Ala attenuated LPS induced sepsis by inhibiting the PI3K/Akt and MAPK signaling pathways.

Topics: Angiotensin I; Animals; Apoptosis; Cell Line; Dose-Response Relationship, Drug; Humans; Inflammation; Kidney; Lipopolysaccharides; Male; Mice; Mice, Inbred C57BL; Oligopeptides; Peptide Fragments; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Sepsis; Signal Transduction

Sepsis, as life-threatening organ dysfunction caused by a dysregulated host response to infection, is characterized by the extensive release of cytokines and other mediators. Sini decoction (SND), a traditional Chinese prescription medicine, has been used clinically for the treatment of sepsis. But its explicit mechanism of action is still unclear. The present study aims to evaluate the potential protective effects of SND on sepsis-induced acute lung injury (ALI). After SND intervention, the lung tissues of each experimental group were collected. H&E sections were used to observe the pathological changes of lung tissue, and alveolar lavage fluid was collected to detect the infiltration of inflammatory cells. Level of inflammatory factors in lung tissue were analyzed by qRT-PCR. The change of Renin angiotensin system (RAS), as well as downstream MAPK/NF-κB signaling pathways were measured by Western blot. For in vitro experiments, human umbilical vein endothelial cells (HUVECs) were pretreated with lipopolysaccharide (LPS) and treated with SND. Subsequently, the expression levels of RAS and MAPK/NF-κB signaling pathways were measured by Western blot. In vivo, we found that SND significantly attenuated sepsis-induced pathological injury in the lung. SND also inhibited LPS-mediated inflammatory cell infiltration, the expression of pro-apoptotic proteins and the production of IL-6, IL-1β, TNF-α and MCP-1. In vitro, experiments using a co-culture of HUVECs with SND showed that there was a decrease in pro-apoptotic protein and pro-inflammatory mediator. In this research, we also found that SND protective action could be attributed to the regulation of renin-angiotensin system (RAS). MAPKs and NF-κB pathways. To conclude, our study demonstrated that SND ameliorates sepsis-induced-ALI via regulating ACE2-Ang (1-7)-Mas axis and inhibiting the MAPK signaling pathway.

Topics: Acute Lung Injury; Angiotensin I; Angiotensin-Converting Enzyme 2; Animals; Bronchoalveolar Lavage Fluid; Disease Models, Animal; Drugs, Chinese Herbal; Human Umbilical Vein Endothelial Cells; Humans; Lung; Male; MAP Kinase Signaling System; Mice, Inbred ICR; Peptide Fragments; Peptidyl-Dipeptidase A; Proto-Oncogene Mas; Proto-Oncogene Proteins; Receptors, G-Protein-Coupled; Sepsis

Sepsis and related multiple organ dysfunction result in high morbidity and mortality. Angiotensin (Ang)-(1-7), a biologically active peptide, has various opposing effects of Ang II. Because the effect of Ang-(1-7) on sepsis is unknown, in this study we aimed to determine the impact of Ang-(1-7) on pathophysiologic changes in a clinically relevant model of polymicrobial sepsis induced by cecal ligation and puncture (CLP).. Sepsis was induced by CLP in rats under anesthesia. Rats were randomized to one of the following five groups: (1) sham-operated group, (2) Ang-(1-7) (1 mg/kg intravenously infused for 1 h) at 3 h and 6 h after sham operation, (3) CLP, (4) Ang-(1-7) at 3 h after CLP, and (5) Ang-(1-7) at 3 h and 6 h after CLP. Rats were observed for 24 h after CLP surgery and then killed for subsequent histological examination.. Ang-(1-7) significantly improved the survival of septic rats (83.3% vs. 36.4% at 24 h following CLP; p = 0.009). Ang-(1-7) attenuated the CLP-induced decreased arterial pressure and organ dysfunction, indicated by diminished biochemical variables and fewer histological changes. Ang-(1-7) significantly reduced the level of plasma interleukin-6 and pulmonary superoxide production (p < 0.05). Moreover, caspase-3 and cytoplasmic IκB expression in liver was significantly lower in the Ang-(1-7)-treated CLP rats (p < 0.05).. In this clinically relevant model of sepsis, Ang-(1-7) ameliorates CLP-induced organ dysfunction and improves survival, possibly through suppressing the inflammatory response, oxidative stress, and apoptosis, suggesting that Ang-(1-7) could be a potential novel therapeutic approach to treatment of peritonitis and polymicrobial sepsis.

Topics: Angiotensin I; Animals; Apoptosis; Biomarkers; Coinfection; Disease Models, Animal; Interleukin-6; Organ Dysfunction Scores; Oxidative Stress; Peptide Fragments; Rats; Rats, Wistar; Sepsis; Statistics, Nonparametric; Superoxides; Tissue Survival

The pressor and intra-renal actions and effects of octa - and deca-peptides angiotensins II and I and of the catecholamine noradrenaline, in anaesthetized and conscious sheep, are considered. The halothane anaesthetic substantially lowers pressor sensitivity to both peptides but does not influence their ability to liberate K(+) ions into the circulating plasma. In comparison with angiotensin II, both angiotensin I and noradrenaline -- with direct presentation to the kidney -- are ineffective in decreasing intra-renal blood flow. However, with left ventricular injection, both pressor compounds immediately increase the blood pressure, as does angiotensin II. Combined doses of the decapeptide and catecholamine are thus highly effective in raising the blood pressure while having a minimal effect on blood flow through the kidney. This overall situation could provide a basis for treating clinical shock, especially regarding septicaemia and septic shock. The lowered hind-limb blood flow, with administration of the pressor compounds into the femoral artery, contrasts strongly with the raised flow resulting from intravenous injection. Experimental procedures to establish, or otherwise, relevant hypothetical situations are detailed.

Topics: Angiotensin I; Angiotensin II; Animals; Electrolytes; Halothane; Kidney; Norepinephrine; Sepsis; Sheep; Shock, Septic

The time course of the components of the renin-angiotensin system was investigated in the plasma of three patients on the intensive care unit. Two of them, which were both polytraumatized, suffered from adult respiratory distress syndrome (ARDS). All patients had sepsis and impaired pulmonary and renal function. Plasma samples were investigated for up to two weeks, in which time all three patients showed a decrease in their angiotensin converting enzyme (ACE) plasma concentration. Two of the patients with deteriorating renal function had three to four times elevated angiotensinogen (Ao) plasma levels, which were measured by both the direct and indirect radioimmunoassay. The ratio of the mean values between both assays was 1:1 in two patients and shifted to higher values in the direct assay in the third patient. This suggests that higher amounts of des-AngI-angiotensinogen were present in the latter patient, because "inactive" Ao is also detected by the direct assay. The decrease in active Ao may be caused by an up to twenty times elevated plasma renin activity (PRA). The PRA was correlated with the angiotensin I (AngI) plasma levels. However, at PRA values higher than 200 pmol AngI/ml/h this correlation decreased because of the rapid substrate consumption. In addition there was a good correlation between AngI and AngII plasma levels in two patients which could not be observed in the patient with the highest PRA and AngII values. A relationship between plasma ACE concentration and AngII formation could not be observed. Thus in two of the three septic patients the components of the renin angiotensin system were extremely stimulated at very low blood pressure values. These data show, that it is reasonable to follow the time course of the components of the renin angiotensin system in single patients. In addition it is demonstrated that the direct measurement of Ao is a valid supplement in the diagnosis of the renin angiotensin system.

Topics: Acute Kidney Injury; Angiotensin I; Angiotensin II; Epinephrine; Furosemide; Humans; Multiple Trauma; Peptidyl-Dipeptidase A; Pneumonia; Renin; Renin-Angiotensin System; Respiratory Distress Syndrome; Sepsis