Effects of intravenous and inhaled levosimendan in severe rodent sepsis

Levosimendan Ameliorates Cardiopulmonary Function but Not Inflammatory Response in a Dual Model of Experimental ARDS

The calcium sensitiser levosimendan, which is used as an inodilator to treat decompensated heart failure, may also exhibit anti-inflammatory properties. We examined whether treatment with levosimendan improves cardiopulmonary function and is substantially beneficial to the inflammatory response in acute respiratory response syndrome (ARDS). Levosimendan was administered intravenously in a new experimental porcine model of ARDS. For comparison, we used milrinone, another well-known inotropic agent. Our results demonstrated that levosimendan intravenously improved hemodynamics and lung function in a porcine ARDS model. Significant beneficial alterations in the inflammatory response and lung injury were not detected.

The direct comparison of inhaled versus intravenous levosimendan in children with pulmonary hypertension undergoing on-cardiopulmonary bypass cardiac surgery: A randomized, controlled, non-inferiority study

STUDY OBJECTIVE

Pulmonary arterial hypertension is commonly seen in children with left to right intracardiac shunts and affects the outcomes of cardiac surgery. Our study aimed to compare the efficacy of inhaled levosimendan (LS) versus intravenous LS in reducing elevated pulmonary artery pressure (PAP) in children scheduled for cardiac surgery.

DESIGN

Non-inferiority, prospective, randomized, blinded, controlled study.

SETTING

Operative room and intensive care unit (ICU), institutional children's hospital of Mansoura Faculty of Medicine, Egypt.

PATIENTS

50 patients of either sex, aged 1 to 5 years undergoing surgical repair of intracardiac left to right shunt complicated by pulmonary hypertension were recruited for the study.

INTERVENTIONS

In the intravenous LS group, patients received intravenous infusion of LS a rate of 0.1 μg/kg/min and in the inhaled LS group, LS (36 μg/kg/6 h) was delivered by nebulization.

MEASUREMENTS

The primary endpoint was systolic PAP, while the secondary endpoints were the heart rate, mean arterial blood pressure, dose of norepinephrine, time to extubation and ICU length of stay.

MAIN RESULTS

Both intravenous and inhaled routes of LS similarly reduced the high systolic PAP over all time points of measurement and intravenous LS was associated with higher heart rate, lower arterial pressure and the need for a higher dose of norepinephrine than the inhaled LS.

CONCLUSION

Inhalation of LS is non-inferior to intravenous LS in reducing high PAP in children who underwent on-pump cardiac surgery and it is associated with less tachycardia and hypotension with reduced need for vasoactive drugs.

Rapid onset of severe septic shock in the pregnant mouse†

AIMS

Globally, sepsis is a major cause of mortality through the combination of cardiovascular collapse and multiorgan dysfunction. Pregnancy appears to increase the risk of death in sepsis, but the exact reason for the greater severity is unclear. In this study, we used polymicrobial sepsis induced by cecal ligation and puncture (CLP) and high-dose intraperitoneal lipopolysaccharide (LPS; 10 or 40 mg, serotype 0111: B4) to test the hypotheses that pregnant mice are more susceptible to sepsis and that this susceptibility was mediated through an excessive innate response causing a more severe cardiovascular collapse rather than a reduction in microbe killing.

METHODS AND RESULTS

Initial studies found that mortality rates were greater, and that death occurred sooner in pregnant mice exposed to CLP and LPS. In pregnant and nonpregnant CD1 mice monitored with radiotelemetry probes, cardiovascular collapse occurred sooner in pregnant mice, but once initiated, occurred over a similar timescale. In a separate study, tissue, serum, and peritoneal fluid (for protein, flow cytometry, nitric oxide, and bacterial load studies) were collected. At baseline, there was no apparent Th1/Th2 bias in pregnant mice. Post CLP, the circulating cytokine response was the same, but leukocyte infiltration in the lung was greater in pregnant mice, but only TNFα levels were greater in lung tissue. The bacterial load in blood and peritoneal fluid was similar in both groups.

CONCLUSION

Sepsis-related mortality was markedly greater in pregnant mice. Cardiovascular collapse and organ dysfunction occurred sooner in pregnancy, but bacterial killing was similar. Circulating and tissue cytokine levels were similar, but immune cell extravasation into other organs was greater in pregnant mice. These data suggest that an excessive innate immune system response as shown by the exaggerated lung infiltration of leukocytes may be responsible for the greater mortality. Approaches that reduce off-site trafficking may improve the prognosis of sepsis in pregnancy.

Cardioprotective and functional effects of levosimendan and milrinone in mice with cecal ligation and puncture-induced sepsis

Levosimendan and milrinone may be used in place of dobutamine to increase cardiac output in septic patients with a low cardiac output due to impaired cardiac function. The effects of the two inotropic agents on cardiac inflammation and left ventricular (LV) performance were examined in mice with cecal ligation and puncture (CLP)-induced sepsis. CLP mice displayed significant cardiac inflammation, as indicated by highly increased pro-inflammatory cytokines and neutrophil infiltration in myocardial tissues. When continuously given, levosimendan prevented but milrinone exaggerated cardiac inflammation, but they significantly reduced the elevations in plasma cardiac troponin-I and heart-type fatty acid-binding protein, clinical markers of cardiac injury. Echocardiographic assessment of cardiac function showed that the effect of levosimendan, given by an intravenous bolus injection, on LV performance was impaired in CLP mice, whereas milrinone produced inotropic responses equally in sham-operated and CLP mice. A lesser effect of levosimendan on LV performance after CLP was also found in spontaneously beating Langendorff-perfused hearts. In ventricular myocytes isolated from control and CLP mice, levosimendan, but not milrinone, caused a large increase in the L-type calcium current. This study represents that levosimendan and milrinone have cardioprotective properties but provide different advantages and drawbacks to cardiac inflammation/dysfunction in sepsis.

Levosimendan reduces mortality in patients with severe sepsis and septic shock: A meta-analysis of randomized trials

PURPOSE

There is controversy about the use of inotropes in the treatment of severe sepsis and septic shock. The objective of this study was to evaluate if levosimendan, as compared with standard inotropic therapy (eg, dobutamine), reduces mortality in septic patients.

MATERIALS AND METHODS

BioMedCentral, PubMed, EMBASE, and the Cochrane Central Register were searched for pertinent studies, up to 1st May 2015. Randomized trials on the use of levosimendan in patients with severe sepsis and septic shock were included if reporting mortality data. The primary outcome was mortality, whereas secondary outcomes were blood lactate, cardiac index, total fluid infused, norepinephrine dosage, and mean arterial pressure.

RESULTS

Seven studies for a total of 246 patients were included in the analysis. Levosimendan was associated with significantly reduced mortality compared with standard inotropic therapy (59/125 [47%] in the levosimendan group and 74/121 [61%] in the control group; risk difference = -0.14, risk ratio = 0.79 [0.63-0.98], P for effect = .03, I(2) = 0%, numbers needed to treat = 7). Blood lactate was significantly reduced in the levosimendan group, whereas cardiac index and total fluid infused were significantly higher in the levosimendan group. No difference in mean arterial pressure and norepinephrine usage was noted.

CONCLUSIONS

In patients with severe sepsis and septic shock, levosimendan is associated with a significant reduction in mortality compared with standard inotropic therapy. A large ongoing multicenter randomized trial will have to confirm these findings.

Levosimendan affects oxidative and inflammatory pathways in the diaphragm of ventilated endotoxemic mice

INTRODUCTION

Controlled mechanical ventilation and endotoxemia are associated with diaphragm muscle atrophy and dysfunction. Oxidative stress and activation of inflammatory pathways are involved in the pathogenesis of diaphragmatic dysfunction. Levosimendan, a cardiac inotrope, has been reported to possess anti-oxidative and anti-inflammatory properties. The aim of the present study was to investigate the effects of levosimendan on markers for diaphragm nitrosative and oxidative stress, inflammation and proteolysis in a mouse model of endotoxemia and mechanical ventilation.

METHODS

Three groups were studied: (1) unventilated mice (CON, n =8), (2) mechanically ventilated endotoxemic mice (MV LPS, n =17) and (3) mechanically ventilated endotoxemic mice treated with levosimendan (MV LPS + L, n =17). Immediately after anesthesia (CON) or after 8 hours of mechanical ventilation, blood and diaphragm muscle were harvested for biochemical analysis.

RESULTS

Mechanical ventilation and endotoxemia increased expression of inducible nitric oxide synthase (iNOS) mRNA and cytokine levels of interleukin (IL)-1β, IL-6 and keratinocyte-derived chemokine, and decreased IL-10, in the diaphragm; however, they had no effect on protein nitrosylation and 4-hydroxy-2-nonenal protein concentrations. Levosimendan decreased nitrosylated proteins by 10% (P <0.05) and 4-hydroxy-2-nonenal protein concentrations by 13% (P <0.05), but it augmented the rise of iNOS mRNA by 47% (P <0.05). Levosimendan did not affect the inflammatory response in the diaphragm induced by mechanical ventilation and endotoxemia.

CONCLUSIONS

Mechanical ventilation in combination with endotoxemia results in systemic and diaphragmatic inflammation. Levosimendan partly decreased markers of nitrosative and oxidative stress, but did not affect the inflammatory response.

Levosimendan attenuates multiple organ injury and improves survival in peritonitis-induced septic shock: studies in a rat model

INTRODUCTION

The aim of this study was to investigate the effects of levosimendan on rodent septic shock induced by cecal ligation and puncture (CLP).

METHODS

Three hours after peritonitis-induced sepsis, male Wistar rats were randomly assigned to receive an intravenous infusion of levosimendan (1.2 μg/kg/min for 10 min and then 0.3 μg/kg/min for 6 h) or an equivalent volume of saline and vehicle (5% dextrose) solution.

RESULTS

The levosimendan-treated CLP animals had significantly higher arterial pressure and lower biochemical indices of liver and kidney dysfunction compared to the CLP animals (P < 0.05). Plasma interleukin-1β, nitric oxide and organ superoxide levels in the levosimendan-treated CLP group were less than those in CLP rats treated with vehicle (P < 0.05). In addition, the inducible nitric oxide synthase (iNOS) in lung and caspase-3 expressions in spleen were significantly lower in the levosimendan-treated CLP group (P < 0.05). The administration of CLP rats with levosimendan was associated with significantly higher survival (61.9% vs. 40% at 18 h after CLP, P < 0.05). At postmortem examination, the histological changes and neutrophil filtration index in liver and lung were significantly attenuated in the levosimendan-treated CLP group (vs. CLP group, P < 0.05).

CONCLUSIONS

In this clinically relevant model of septic shock induced by fecal peritonitis, the administration of levosimendan had beneficial effects on haemodynamic variables, liver and kidney dysfunction, and metabolic acidosis. (1) Lower levels of interleukin-1β, nitric oxide and superoxide, (2) attenuation of iNOS and caspase-3 expressions, and (3) decreases of neutrophil infiltration by levosimendan in peritonitis-induced sepsis animals suggest that anti-inflammation and anti-apoptosis effects of levosimendan contribute to prolonged survival.

In contrast to its anti-inflammatory and anti-apoptotic peripheral effect, levosimendan failed to induce a long-term neuroprotective effect in a rat model of mild septic encephalopathy: a pilot study

Levosimendan shows protective myocardial characteristics and is administered to enhance cardiac contractility in patients. However, currently little is known about levosimendan's effect on brain. The aim of this pilot study was to investigate the long-term effect of levosimendan on brain and during mild rat sepsis in comparison to its peripheral mode of action. Adult rats (n=40) were divided into four groups with n=10 per group: (I) sham, (II) levosimendan (283 μg/kg body weight i.v.), (III) lipopolysaccharide (LPS, 8 mg/kg body weight i.p.), and (IV) LPS+levosimendan. Levosimendan was given 24h after injecting LPS. Psychometric investigations were conducted using a Morris water maze (MWM) and a holeboard test. In cerebral and splenic tissue, IL-1β, Il-6, TNFalpha levels, and apoptosis were determined; cerebral tissue corticosterone concentration was measured 6 days after injecting LPS. Blood cytokine concentrations were determined 1 day and 6 days after injecting LPS. Rats that received an LPS injection spent more time in the outer zone of the MWM according to increased cerebral corticosterone levels, and showed decreased cognitive abilities. LPS induced a reduction in body weight, increased splenic apoptosis and blood cytokine level. Levosimendan showed anti-inflammatory and anti-apoptotic properties in spleen but failed to show a long-term neuroprotective effect.

Levosimendan's effect on platelet function in a rat sepsis model

Although studies have evaluated the efficacy of levosimendan in heart failure during sepsis, it still is a subject of controversy whether levosimendan produces an effect on platelets. In this study, the short- and long-term effects of levosimendan on platelet aggregation were investigated in untreated animals and in a rat model of sepsis. Therefore, adult rats (n = 40) were randomly divided into four groups with n = 10 per group: (I) sham, (II) levosimendan (bolus 53 µg/kg + 285 µg/kg/hour, intravenously (i.v.) injected), (III) LPS (lipopolysaccharide, 8 mg/kg body weight intraperitoneally injected), and (IV) LPS + levosimendan. Levosimendan was given 24 hours after LPS injections. The number of platelets was determined. Platelet aggregation was measured using venous blood from rats 10 minutes and 5 days after levosimendan application with Dynabyte Multiplate system. Aggregation responses were evaluated with adenosine diphosphate (10 µM) and collagen (5 µg/ml). In addition to clinical dosage, the in vitro effect of high-dosage levosimendan on platelet function was investigated. The results clearly showed that LPS significantly reduced the platelet aggregation 1 day after injection compared to controls; 6 days after LPS, a marked increase (p < 0.01) was noted. This result is associated with numbers of platelets. Levosimendan (bolus 53 µg/kg + 285 µg/kg/hour i.v.) had no significant effect on the platelets of rats in contrast to the high-dosage in vitro findings. Thus, the in vivo use of levosimendan does not affect blood coagulation significantly in this rat model. This also applies under the conditions of decreased and increased numbers of platelets during mild sepsis.

Pharmacological targets in the renal peritubular microenvironment: implications for therapy for sepsis-induced acute kidney injury

One of the most frequent and serious complications to develop in septic patients is acute kidney injury (AKI), a disorder characterized by a rapid failure of the kidneys to adequately filter the blood, regulate ion and water balance, and generate urine. AKI greatly worsens the already poor prognosis of sepsis and increases cost of care. To date, therapies have been mostly supportive; consequently there has been little change in the mortality rates over the last decade. This is due, at least in part, to the delay in establishing clinical evidence of an infection and the associated presence of the systemic inflammatory response syndrome and thus, a delay in initiating therapy. A second reason is a lack of understanding regarding the mechanisms leading to renal injury, which has hindered the development of more targeted therapies. In this review, we summarize recent studies, which have examined the development of renal injury during sepsis and propose how changes in the peritubular capillary microenvironment lead to and then perpetuate microcirculatory failure and tubular epithelial cell injury. We also discuss a number of potential therapeutic targets in the renal peritubular microenvironment, which may prevent or lessen injury and/or promote recovery.

The effects of levosimendan and glibenclamide on circulatory and metabolic variables in a canine model of acute hypoxia

PURPOSE

To study the effects of pretreatment with levosimendan (LEVO, a Ca²(+)-sensitizer and K (ATP) (+) channel opener) and/or the K (ATP) (+) channel antagonist glibenclamide (GLIB) on systemic hemodynamics, metabolism, and regional gastromucosal oxygenation during hypoxic hypoxemia.

METHODS

Chronically instrumented, healthy dogs (24-32 kg, n = 6 per group, randomized cross-over design) were repeatedly sedated, mechanically ventilated (FiO₂ ~0.3) and subjected to the following interventions: no pretreatment, LEVO pretreatment, GLIB pretreatment, or combined LEVO + GLIB pretreatment, each followed by hypoxic hypoxemia (FiO₂ ~0.1). We measured cardiac output (CO, ultrasonic flow probes), oxygen consumption (VO₂, indirect calorimetry), and gastromucosal microvascular hemoglobin oxygenation (μHbO₂, spectrophotometry).

STATISTICS

data are presented as mean ± SEM and compared by one-way ANOVA (direct drug effects within group) and two-way ANOVA (between all hypoxic conditions) both with Bonferroni corrections; p < 0.05.

RESULTS

In LEVO-pretreated hypoxemia, CO was significantly higher compared to unpretreated hypoxemia. The increased CO was neither associated with an increased VO₂ nor with markers of aggravated anaerobiosis (pH, BE, lactate). In addition, LEVO pretreatment did not further compromise gastromucosal μHbO₂ in hypoxemia. After combined LEVO + GLIB pretreatment, systemic effects of GLIB were apparent, however, CO was significantly higher than during unpretreated and GLIB-pretreated hypoxemia, but equal to LEVO-pretreated hypoxemia, indicating that GLIB did not prevent the increased CO in LEVO-pretreated hypoxia.

CONCLUSIONS

LEVO pretreatment resulted in improved systemic circulation (CO) during hypoxemia without fueling systemic VO₂, without aggravating systemic anaerobiosis markers, and without further compromising microvascular gastromucosal oxygenation. Thus, LEVO pretreatment may be an option to support the systemic circulation during hypoxia.

Comparing hemodynamics, blood gas analyses and proinflammatory cytokines in endotoxemic and severely septic rats

Lipopolysaccharide (LPS) is often used in short-term models of inflammation. Since endotoxemia and sepsis are different entities we have recently established a short-term sepsis model in rats induced by cecal ligation and incision (CLI). This retrospective study was conducted in order to identify similarities and differences between both experimental approaches. 32 anesthetized/ventilated male rats from the following four groups were analysed (each n=8): CTRL-group (0.9% NaCl i.v.); LPS-group (5mg/kg i.v.); SHAM-group (laparotomy); CLI-group (1.5 cm blade incision). Mean arterial blood pressure (MAP) and blood gas parameters (arterial base excess (BE) and pH) were continuously recorded. Total observation time was 300 min. Plasma samples were obtained afterwards. LPS and CLI induced significant arterial hypotension and metabolic acidosis compared to CTRL- or SHAM-group, respectively. Yet, between the LPS- and CLI-groups, there were no differences in MAP, BE and pH. LPS significantly induced IL-1β, IL-6 and TNF-α in the plasma. In contrast, CLI showed a clear tendency towards increased IL-1β and IL-6 plasma levels and did not affect TNF-α. Our results indicate that the CLI sepsis model is suitable for short-term investigations on hemodynamic alterations and blood gas analyses during sepsis. 300 min after the proinflammatory insult, plasma concentrations of IL-1β and IL-6 in the plasma remain considerably lower after CLI compared to endotoxemia. Low TNF-α concentrations 300 min after sepsis induction could be interpreted as considerable immunosuppression during CLI sepsis.

Effects of short-term infusion of lipid emulsions on pro-inflammatory cytokines and lymphocyte apoptosis in septic and non-septic rats

Long-term administration of PUFA is known to modulate immune functions and apoptotic pathways depending on the respective amount of n-6 and n-3 fatty acids (FA). Data on short-term effects on apoptotic pathways are rare. Apoptosis of splenic lymphocytes is the hallmark of detrimental sepsis. Therefore, we aimed to compare the immediate effects of parenterally administered n-6-enriched soyabean oil (SO)- and n-3-enriched fish oil (FO)-based lipid emulsions after laparotomy (LAP; sham procedure) and after induction of acute, severe sepsis by caecal ligation and incision. After 390 min of observation time, plasma was analysed for IL-1β, IL-6 and NEFA. Apoptosis in splenic lymphocytes was quantified by Annexin-V expression. After LAP, infusion of both FO and SO did not change cytokine concentrations. Sepsis increased both cytokines. FO but not SO further augmented the rise. After LAP, SO increased NEFA, and both lipid emulsions reduced free arachidonic acid (AA). Sepsis resulted in a dramatic decrease in NEFA and AA. The drop in NEFA and AA was prevented by both SO and FO. In addition, FO resulted in an increased concentration of n-3 FA under both conditions. Infusion of both lipid emulsions induced apoptosis in splenic lymphocytes after LAP. Sepsis-induced apoptosis was not further enhanced by FO or SO. The present study shows that short-term administration of FO as opposed to SO caused pro-inflammatory effects during sepsis. Moreover, short-term administration of both SO and FO suffices to induce apoptosis in splenic lymphocytes. Finally, SO and FO do not further enhance sepsis-induced splenic apoptosis.

Levosimendan for resuscitating the microcirculation in patients with septic shock: a randomized controlled study

INTRODUCTION

The purpose of the present study was to investigate microcirculatory blood flow in patients with septic shock treated with levosimendan as compared to an active comparator drug (i.e. dobutamine). The primary end point was a difference of ≥ 20% in the microvascular flow index of small vessels (MFIs) among groups.

METHODS

The study was designed as a prospective, randomized, double-blind clinical trial and performed in a multidisciplinary intensive care unit. After achieving normovolemia and a mean arterial pressure of at least 65 mmHg, 40 septic shock patients were randomized to receive either levosimendan 0.2 μg·kg(-1)·min(-1) (n = 20) or an active comparator (dobutamine 5 μg·kg(-1)·min(-1); control; n = 20) for 24 hours. Sublingual microcirculatory blood flow of small and medium vessels was assessed by sidestream dark-field imaging. Microcirculatory variables and data from right heart catheterization were obtained at baseline and 24 hours after randomization. Baseline and demographic data were compared by means of Mann-Whitney rank sum test or chi-square test, as appropriate. Microvascular and hemodynamic variables were analyzed using the Mann-Whitney rank sum test.

RESULTS

Microcirculatory flow indices of small and medium vessels increased over time and were significantly higher in the levosimendan group as compared to the control group (24 hrs: MFIm 3.0 (3.0; 3.0) vs. 2.9 (2.8; 3.0); P = .02; MFIs 2.9 (2.9; 3.0) vs. 2.7 (2.3; 2.8); P < .001). The relative increase of perfused vessel density vs. baseline was significantly higher in the levosimendan group than in the control group (dMFIm 10 (3; 23)% vs. 0 (-1; 9)%; P = .007; dMFIs 47 (26; 83)% vs. 10 (-3; 27); P < .001). In addition, the heterogeneity index decreased only in the levosimendan group (dHI -93 (-100; -84)% vs. 0 (-78; 57)%; P < .001). There was no statistically significant correlation between systemic and microcirculatory flow variables within each group (each P > .05).

CONCLUSIONS

Compared to a standard dose of 5 μg·kg(-1)·min(-1) of dobutamine, levosimendan at 0.2 μg·kg(-1)·min(-1) improved sublingual microcirculatory blood flow in patients with septic shock, as reflected by changes in microcirculatory flow indices of small and medium vessels.

TRIAL REGISTRATION

NCT00800306.