Effects of volume resuscitation on splanchnic perfusion in canine model of severe sepsis induced by live Escherichia coli infusion

INTRODUCTION: We conducted the present study to investigate whether early large-volume crystalloid infusion can restore gut mucosal blood flow and mesenteric oxygen metabolism in severe sepsis. METHODS: Anesthetized and mechanically ventilated male mongrel dogs were challenged with intravenous injection of live Escherichia coli (6 × 10(9 )colony-forming units/ml per kg over 15 min). After 90 min they were randomly assigned to one of two groups – control (no fluids; n = 13) or lactated Ringer's solution (32 ml/kg per hour; n = 14) – and followed for 60 min. Cardiac index, mesenteric blood flow, mean arterial pressure, systemic and mesenteric oxygen-derived variables, blood lactate and gastric carbon dioxide tension (PCO(2); by gas tonometry) were assessed throughout the study. RESULTS: E. coli infusion significantly decreased arterial pressure, cardiac index, mesenteric blood flow, and systemic and mesenteric oxygen delivery, and increased arterial and portal lactate, intramucosal PCO(2), PCO(2 )gap (the difference between gastric mucosal and arterial PCO(2)), and systemic and mesenteric oxygen extraction ratio in both groups. The Ringer's solution group had significantly higher cardiac index and systemic oxygen delivery, and lower oxygen extraction ratio and PCO(2 )gap at 165 min as compared with control animals. However, infusion of lactated Ringer's solution was unable to restore the PCO(2 )gap. There were no significant differences between groups in mesenteric oxygen delivery, oxygen extraction ratio, or portal lactate at the end of study. CONCLUSION: Significant disturbances occur in the systemic and mesenteric beds during bacteremic severe sepsis. Although large-volume infusion of lactated Ringer's solution restored systemic hemodynamic parameters, it was unable to correct gut mucosal PCO(2 )gap

Small volume of hypertonic saline as the initial fluid replacement in experimental hypodynamic sepsis

INTRODUCTION: We conducted the present study to examine the effects of hypertonic saline solution (7.5%) on cardiovascular function and splanchnic perfusion in experimental sepsis. METHODS: Anesthetized and mechanically ventilated mongrel dogs received an intravenous infusion of live Escherichia coli over 30 minutes. After 30 minutes, they were randomized to receive lactated Ringer's solution 32 ml/kg (LR; n = 7) over 30 minutes or 7.5% hypertonic saline solution 4 ml/kg (HS; n = 8) over 5 minutes. They were observed without additional interventions for 120 minutes. Cardiac output (CO), mean arterial pressure (MAP), portal and renal blood flow (PBF and RBF, respectively), gastric partial pressure of CO(2 )(pCO(2); gas tonometry), blood gases and lactate levels were assessed. RESULTS: E. coli infusion promoted significant reductions in CO, MAP, PBF and RBF (approximately 45%, 12%, 45% and 25%, respectively) accompanied by an increase in lactate levels and systemic and mesenteric oxygen extraction (sO(2)ER and mO(2)ER). Widening of venous-arterial (approximately 15 mmHg), portal-arterial (approximately 18 mmHg) and gastric mucosal-arterial (approximately 55 mmHg) pCO(2 )gradients were also observed. LR and HS infusion transiently improved systemic and regional blood flow. However, HS infusion was associated with a significant and sustained reduction of systemic (18 ± 2.6 versus 38 ± 5.9%) and mesenteric oxygen extraction (18.5 ± 1.9 versus 36.5 ± 5.4%), without worsening other perfusional markers. CONCLUSION: A large volume of LR or a small volume of HS promoted similar transient hemodynamic benefits in this sepsis model. However, a single bolus of HS did promote sustained reduction of systemic and mesenteric oxygen extraction, suggesting that hypertonic saline solution could be used as a salutary intervention during fluid resuscitation in septic patients

Early effects of 7.5% hypertonic saline solution on splanchnic perfusion after hemorrhagic shock

PURPOSE: To evaluate the effects of SSH resuscitation on systemic and splanchnic hemodynamic variables in an experimental model of controlled hemorrhagic shock. METHODS: Ten mongrel dogs were bled (20 ml/min) to a target mean arterial pressure (MAP) of 40±5 mmHg. After 30 minutes of shock, animals received SSH infused in 5-minute and they were observed for 60 minutes thereafter. Systemic hemodynamics were evaluated through a Swan-Ganz and arterial catheters while gastrointestinal tract perfusion by a catheter inside the portal vein, an ultrasonic flowprobe around portal vein blood flow (PVBF) and a gastric tonometer. Splanchnic oxygen delivery and consumption, intramucosal pH and veno-arterial, portal-arterial and mucosal-arterial pCO2-gradients (Dap-a pCO2, Dvp-a pCO2 e Dt-a pCO2, respectively) were assessed. RESULTS: Hemorrhage (29.8±2.4ml/Kg) induced significant decreases in MAP (125±6 to 42±1 mmHg), in CO (1.9±0.2 to 0.6±0.1 L/min), and PVBF (504±73 to 126±12 ml/min) while significant increases were detected in Dap-a pCO2 (5.3±0.8 to 19.9±1.6 mmHg) Dvp-a pCO2 (5.4±1.4 to 22.6±2.1 mmHg) and Dt-a pCO2 (6.1±1.1 to 43.8±7.5 mmHg). SSH infusion promoted only partial benefits in systemic and splanchnic blood flows. Reduced pCO2 gradients but fewer effects in Dt-a pCO2 were observed. CONCLUSION: The SSH infusion promoted partial systemic and splanchnic hemodynamic benefits. Those benefits were especially poor at the splanchnic microcirculation, as evaluated by Dt-a pCO2. In addition, systemic and regional oxygen-derived variables do not reflect the regional microcirculation disturbances. Gastrointestinal tonometry clearly represents a useful tool for monitoring splanchnic perfusion in patients in hemodynamic shock.OBJETIVO: Avaliar os efeitos hemodinâmicos sistêmicos e esplâncnico da expansão volêmica inicial com SSH em modelo de choque hemorrágico controlado. MÉTODOS: Dez cães foram submetidos a sangramento controlado (20 ml/min) até uma pressão arterial média de 40±5 mmHg (PAM). Após 30 minutos de choque, receberam 4 ml/Kg de SSH em 5 minutos e posteriormente observados sem intervenções adicionais durante 60 minutos. As variáveis hemodinâmicas sistêmicas foram obtidas de um cateter arterial e de um cateter de Swan-Ganz, enquanto as regionais através da cateterização da veia porta, fluxômetro ultrassônico na veia porta e um tonômetro na cavidade. A oferta, taxa de extração e consumo esplâncnico de oxigênio, pH intramucoso e os gradientes veno-arterial, porta-arterial e mucosa-arterial da pCO2 (Dap-a pCO2, Dvp-a pCO2 e Dt-a pCO2, respectivamente), foram calculados. RESULTADOS: A hemorragia (29,8±2,4 ml/Kg) reduziu a pressão arterial média (125±6 para 42±1 mmHg), o DC (1,9±0,2 para 0,6±0,1 L/min) e o fluxo porta (504±73 para 126±12 ml/min), enquanto elevou o Dap-a pCO2 (5,3±0,8 para 19,9±1,6 mmHg), Dvp-a pCO2 (5,4±1,4 para 22,6±2,1 mmHg) e o Dt-a pCO2 (6,1±1,1 para 43,8±7,5 mmHg). A infusão de SSH resultou em recuperação parcial dos fluxos sistêmico e porta. Atenuou os gradientes de CO2 com menor impacto sobre o Dt-a pCO2. CONCLUSÃO: A SSH promoveu benefícios parciais na perfusão sistêmica e esplâncnica, os quais foram especialmente limitados na microcirculação regional, como demonstrado pelo Dt-a pCO2. Além disso, as variáveis sistêmicas e regionais dependentes de oxigênio, não refletem a adequação da perfusão da mucosa gástrica, enfatizando a importância da monitorização deste território - pela tonometria - durante os estados de choque.USP FM InCorUNIFESP-EPM Depto. de CirurgiaUSP FM Depto. de CardiopneumologiaUNIFESP, EPM, Depto. de CirurgiaSciEL

In vivo evaluation of isolated triterpenes and semi-synthetic derivatives as antimalarial agents

The triterpenes balsaminoside B (1) and karavilagenin C (2) were isolated from the African medicinal plant Momordica balsamina L. Karavoates B (3) and D (4) were synthesized by diacylation of 2 with acetic and propionic anhydrides, respectively. In previous work, derivatives 3 and 4 exhibited submicromolar median inhibitory concentrations (IC50) in vitro against Plasmodium falciparum Welch (human malaria parasite) strains 20 to 25 times lower than those of natural product 2. The main objective of the present study was to explore structure-in vivo antimalarial activity relationships (SAR) for compounds 1-4 in Plasmodium berghei Vincke and Lips NK65-infected mice in the 4 day suppressive test. Semi-synthetic derivatives 3 and 4 exhibited greater in vivo antimalarial activity than isolates 1 and 2. Orally and subcutaneously administered karavoate B exhibited the greatest in vivo antimalarial activity (55.2-58.1% maximal suppression of parasitemia at doses of 50 mg kg-1 day-1). Diacylation of natural isolate 2 with short chain carboxylic acid moieties yielded derivatives with enhanced maximal in vivo parasitemia suppression for both routes of administration. Maximal in vivo parasite suppression by diacetyl derivative 3 was roughly double that of natural precursor 2. © 2015 Published by Elsevier Masson SAS

Mesenteric Microcirculatory Dysfunctions and Translocation of Indigenous Bacteria in a Rat Model of Strangulated Small Bowel Obstruction

PRUPOSE: Bacterial translocation has been shown to occur in critically ill patients after extensive trauma, shock, sepsis, or thermal injury. The present study investigates mesenteric microcirculatory dysfunctions, the bacterial translocation phenomenon, and hemodynamic/metabolic disturbances in a rat model of intestinal obstruction and ischemia. METHODS: Anesthetized (pentobarbital 50 mg/kg, i.p.) male Wistar rats (250-350 g) were submitted to intestinal obstruction or laparotomy without intestinal obstruction (Sham) and were evaluated 24 hours later. Bacterial translocation was assessed by bacterial culture of the mesenteric lymph nodes (MLN), liver, spleen, and blood. Leukocyte-endothelial interactions in the mesenteric microcirculation were assessed by intravital microscopy, and P-selectin and intercellular adhesion molecule (ICAM)-1 expressions were quantified by immunohistochemistry. Hematocrit, blood gases, lactate, glucose, white blood cells, serum urea, creatinine, bilirubin, and hepatic enzymes were measured. RESULTS: About 86% of intestinal obstruction rats presented positive cultures for E. coli in samples of the mesenteric lymph nodes, liver, and spleen, and 57% had positive hemocultures. In comparison to the Sham rats, intestinal obstruction induced neutrophilia and increased the number of rolling (~2-fold), adherent (~5-fold), and migrated leukocytes (~11-fold); this increase was accompanied by an increased expression of P-selectin (~2-fold) and intercellular adhesion molecule-1 (~2-fold) in the mesenteric microcirculation. Intestinal obstruction rats exhibited decreased PaCO2, alkalosis, hyperlactatemia, and hyperglycemia, and increased blood potassium, hepatic enzyme activity, serum urea, creatinine, and bilirubin. A high mortality rate was observed after intestinal obstruction (83% at 72 h vs. 0% in Sham rats). CONCLUSION: Intestinal obstruction and ischemia in rats is a relevant model for the in vivo study of mesenteric microcirculatory dysfunction and the occurrence of bacterial translocation. This model parallels the events implicated in multiple organ dysfunction (MOD) and death

Chemical composition of aspidosperma ulei markgr. and antiplasmodial activity of selected indole alkaloids

A new indole alkaloid, 12-hydroxy-N-acetyl-21(N)-dehydroplumeran-18-oic acid (13), and 11 known indole alkaloids: 3,4,5,6-tetradehydro-β-yohimbine (3), 19(E)- hunteracine (4), β-yohimbine (5), yohimbine (6), 19,20-dehydro-17-α-yohimbine (7), uleine (10), 20-epi-dasycarpidone (11), olivacine (8), 20-epi-N-nor-dasycarpidone (14), N-demethyluleine (15) and 20(E)-nor-subincanadine E (12) and a boonein △-lactone 9, ursolic acid (1) and 1D,1O-methyl-chiro-inositol (2) were isolated from the EtOH extracts of different parts of Aspidosperma ulei Markgr. (Apocynaceae). Identification and structural elucidation were based on IR, MS, 1H- and 13C-NMR spectral data and comparison to literature data. The antiplasmodial and antimalarial activity of 1, 5, 6, 8, 10 and 15 has been previously evaluated and 1 and 10 have important in vitro and in vivo antimalarial properties according to patent and/or scientific literature. With the aim of discovering new antiplasmodial indole alkaloids, 3, 4, 11, 12 and 13 were evaluated for in vitro inhibition against the multi-drug resistant K1 strain of the human malaria parasite Plasmodium falciparum. IC50 values of 14.0 (39.9), 4.5 (16.7) and 14.5 (54.3) μg/mL (μM) were determined for 3, 11 and 12, respectively. Inhibitory activity of 3, 4, 11, 12 and 13 was evaluated against NIH3T3 murine fibroblasts. None of these compounds exhibited toxicity to fibroblasts (IC50 > 50 μg/mL). Of the five compounds screened for in vitro antiplasmodial activity, only 11 was active. © 2013 by the authors

Amazonian plant natural products:perspectives for discovery of new antimalarial drug leads

Plasmodium falciparum and P. vivax malaria parasites are now resistant, or showing signs of resistance, to most drugs used in therapy. Novel chemical entities that exhibit new mechanisms of antiplasmodial action are needed. New antimalarials that block transmission of Plasmodium spp. from humans to Anopheles mosquito vectors are key to malaria eradication efforts. Although P. vivax causes a considerable number of malaria cases, its importance has for long been neglected. Vivax malaria can cause severe manifestations and death; hence there is a need for P. vivax-directed research. Plants used in traditional medicine, namely Artemisia annua and Cinchona spp. are the sources of the antimalarial natural products artemisinin and quinine, respectively. Based on these compounds, semi-synthetic artemisinin-derivatives and synthetic quinoline antimalarials have been developed and are the most important drugs in the current therapeutic arsenal for combating malaria. In the Amazon region, where P. vivax predominates, there is a local tradition of using plant-derived preparations to treat malaria. Here, we review the current P. falciparum and P. vivax drug-sensitivity assays, focusing on challenges and perspectives of drug discovery for P. vivax, including tests against hypnozoites. We also present the latest findings of our group and others on the antiplasmodial and antimalarial chemical components from Amazonian plants that may be potential drug leads against malaria

In vitro susceptibility of Plasmodium falciparum Welch field isolates to infusions prepared from Artemisia annua L. cultivated in the Brazilian Amazon

Artemisinin is the active antimalarial compound obtained from the leaves of Artemisia annua L. Artemisinin, and its semi-synthetic derivatives, are the main drugs used to treat multi-drug-resistant Plasmodium falciparum (one of the human malaria parasite species). The in vitro susceptibility of P. falciparum K1 and 3d7 strains and field isolates from the state of Amazonas, Brazil, to A. annua infusions (5 g dry leaves in 1 L of boiling water) and the drug standards chloroquine, quinine and artemisinin were evaluated. The A. annua used was cultivated in three Amazon ecosystems (várzea, terra preta de índio and terra firme) and in the city of Paulínia, state of São Paulo, Brazil. Artemisinin levels in the A. annua leaves used were 0.90-1.13% (m/m). The concentration of artemisinin in the infusions was 40-46 mg/L. Field P. falciparum isolates were resistant to chloroquine and sensitive to quinine and artemisinin. The average 50% inhibition concentration values for A. annua infusions against field isolates were 0.11-0.14 μL/mL (these infusions exhibited artemisinin concentrations of 4.7-5.6 ng/mL) and were active in vitro against P. falciparum due to their artemisinin concentration. No synergistic effect was observed for artemisinin in the infusions

In vitro and in vivo anti-malarial activity of limonoids isolated from the residual seed biomass from Carapa guianensis (andiroba) oil production

Background: Carapa guianensis is a cultivable tree used by traditional health practitioners in the Amazon region to treat several diseases and particularly symptoms related to malaria. Abundant residual pressed seed material (RPSM) results as a by-product of carapa or andiroba oil production. The objective of this study was to evaluate the in vitro and in vivo anti-malarial activity and cytotoxicity of limonoids isolated from C. guaianensis RPSM.Methods. 6-acetoxyepoxyazadiradione (1), andirobin (2), 6-acetoxygedunin (3) and 7-deacetoxy-7-oxogedunin (4) (all isolated from RPSM using extraction and chromatography techniques) and 6-hydroxy-deacetylgedunin (5) (prepared from 3) were evaluated using the micro test on the multi-drug-resistant Plasmodium falciparum K1 strain. The efficacy of limonoids 3 and 4 was then evaluated orally and subcutaneously in BALB/c mice infected with chloroquine-sensitive Plasmodium berghei NK65 strain in the 4-day suppressive test.Results: In vitro, limonoids 1-5 exhibited median inhibition concentrations (IC50) of 20.7-5.0 μM, respectively. In general, these limonoids were not toxic to normal cells (MRC-5 human fibroblasts). In vivo, 3 was more active than 4. At oral doses of 50 and 100 mg/kg/day, 3 suppressed parasitaemia versus untreated controls by 40 and 66%, respectively, evidencing a clear dose-response.Conclusion: 6-acetoxygedunin is an abundant natural product present in C. guianensis residual seed materials that exhibits significant in vivo anti-malarial properties. © 2014 Pereira et al.; licensee BioMed Central Ltd.x

In vivo antimalarial activity and mechanisms of action of 4-nerolidylcatechol derivatives

4-Nerolidylcatechol (1) is an abundant antiplasmodial metabolite that is isolated from Piper peltatum roots. O-Acylation or O-alkylation of compound 1 provides derivatives exhibiting improved stability and significant in vitro antiplasmodial activity. The aim of this work was to study the in vitro inhibition of hemozoin formation, inhibition of isoprenoid biosynthesis in Plasmodium falciparum cultures, and in vivo antimalarial activity of several 4-nerolidylcatechol derivatives. 1,2-O,O-Diacetyl-4-nerolidylcatechol (2) inhibited in vitro hemozoin formation by up to 50%. In metabolic labeling studies using [1-(n)-3H]geranylgeranyl pyrophosphate, diester 2 significantly inhibited the biosynthesis of isoprenoid metabolites ubiquinone 8, menaquinone 4, and dolichol 12 in cultures of P. falciparum 3D7. Similarly, 2-O-benzyl-4-nerolidylcatechol (3) significantly inhibited the biosynthesis of dolichol 12. P. falciparum in vitro protein synthesis was not affected by compounds 2 or 3. At oral doses of 50 mg per kg of body weight per day, compound 2 suppressed Plasmodium berghei NK65 in infected BALB/c mice by 44%. This in vivo result for derivative 2 represents marked improvement over that obtained previously for natural product 1. Compound 2 was not detected in mouse blood 1 h after oral ingestion or in mixtures with mouse blood/blood plasma in vitro. However, it was detected after in vitro contact with human blood or blood plasma. Derivatives of 4-nerolidylcatechol exhibit parasite-specific modes of action, such as inhibition of isoprenoid biosynthesis and inhibition of hemozoin formation, and they therefore merit further investigation for their antimalarial potential. Copyright © 2015, American Society for Microbiology. All Rights Reserved