Effects and Mechanism Analysis of Combined Infusion by Levosimendan and Vasopressin on Acute Lung Injury in Rats Septic Shock

Heart Dysfunction in Sepsis

Cardiac involvement during sepsis frequently occurs. A series of molecules induces a set of changes at the cellular level that result in the malfunction of the myocardium. The understanding of these molecular alterations has simultaneously promoted the implementation of diagnostic strategies that are much more precise and allowed the advance of the therapeutics. The heart is a vital organ for survival. Its well-being ensures the adequate supply of essential elements for organs and tissues.

Use of Levosimendan in Intensive Care Unit Settings: An Opinion Paper

Levosimendan is an inodilator that promotes cardiac contractility primarily through calcium sensitization of cardiac troponin C and vasodilatation via opening of adenosine triphosphate–sensitive potassium (K_ATP) channels in vascular smooth muscle cells; the drug also exerts organ-protective effects through a similar effect on mitochondrial K_ATP channels. This pharmacological profile identifies levosimendan as a drug that may have applications in a wide range of critical illness situations encountered in intensive care unit medicine: hemodynamic support in cardiogenic or septic shock; weaning from mechanical ventilation or from extracorporeal membrane oxygenation; and in the context of cardiorenal syndrome. This review, authored by experts from 9 European countries (Austria, Belgium, Czech republic, Finland, France, Germany, Italy, Sweden, and Switzerland), examines the clinical and experimental data for levosimendan in these situations and concludes that, in most instances, the evidence is encouraging, which is not the case with other cardioactive and vasoactive drugs routinely used in the intensive care unit. The size of the available studies is, however, limited and the data are in need of verification in larger controlled trials. Some proposals are offered for the aims and designs of these additional studies.

Altered pulmonary capillary permeability in immunosuppressed guinea pigs infected with Legionella pneumophila serogroup 1

In immunosuppressed hosts, Legionella pneumophila (Lp) infection usually develops into severe pneumonia, which is pathologically characterized by increased vascular permeability and pulmonary edema. At present, mechanisms associated with changes in pulmonary capillary permeability (PCP) and the pathogenesis of pulmonary edema in immunosuppressed hosts with Lp infection are unclear. Therefore, in the present study an animal model of normal and immunosuppressed guinea pigs infected with Lp was established. An isolated perfused lung system was used to investigate the extent of changes in PCP. Pathological and immunofluorescence examinations were performed to explore the mechanism underlying these changes. The results indicated that PCP increased with the highest magnitude in immunosuppressed guinea pigs infected with Lp, with repeated ANOVA indicating synergism between infection and immunosuppression (P=0.0444). Hematoxylin and eosin staining and electron microscopy revealed more severe morphological damages in the lung tissues and pulmonary capillaries of the immunosuppressed animals infected with Lp compared with normal animals infected with Lp. Immunofluorescence analysis showed that immunosuppression reduced the expression of the vascular endothelial cell junction protein VE-cadherin (P=0.027). Following Lp infection, VE-cadherin expression was significantly lower in the immunosuppressed guinea pigs compared with their immunocompetent counterparts (P=0.001). These results suggest that immunosuppression combined with Lp infection induces more significant damage to pulmonary capillaries compared with Lp infection alone, resulting in a significantly increased PCP.

Preclinical septic shock research: why we need an animal ICU

Animal experiments are widely used in preclinical medical research with the goal of disease modeling and exploration of novel therapeutic approaches. In the context of sepsis and septic shock, the translation into clinical practice has been disappointing. Classical animal models of septic shock usually involve one-sex-one-age animal models, mostly in mice or rats, contrasting with the heterogeneous population of septic shock patients. Many other factors limit the reliability of preclinical models and may contribute to preclinical research failure in critical care, including the host specificity of several pathogens, the fact that laboratory animals are raised in pathogen-free facilities and that organ support techniques are either absent or minimal. Advanced animal models have been developed with the aim of improving the clinical translatability of experimental findings. So-called animal ICUs refer to the preclinical investigation of adult or even aged animals of either sex, using—in case of rats and mice—miniaturized equipment allowing for reproducing an ICU environment at a small animal scale and integrating chronic comorbidities to more closely reflect the clinical conditions studied. Strength and limitations of preclinical animal models designed to decipher the mechanisms involved in septic cardiomyopathy are discussed. This article reviews the current status and the challenges of setting up an animal ICU.

[Heart in sepsis : Molecular mechanisms, diagnosis and therapy of septic cardiomyopathy]

An impairment of cardiac function is a key feature of cardiovascular failure associated with sepsis; however, its clinical relevance is still underestimated. Recent advancements in echocardiography in patients with septic shock enable a better characterization of septic cardiomyopathy by unmasking a severe, cardiac dysfunction even in the presence of preserved left ventricular ejection fraction. The pathophysiology of septic cardiomyopathy involves a complex mixture of systemic factors and molecular, metabolic, and structural changes of the cardiomyocytes. A better understanding of these factors will enable the discovery of new therapeutic targets for urgently needed disease-modifying therapeutic interventions. To date, the cornerstone of therapeutic management lies in control of the underlying infectious process and hemodynamic stabilization. This review summarizes the pathogenesis, diagnosis, and treatment of septic cardiomyopathy, and highlights the importance of further urgently needed studies aimed at improving diagnosis and treatment for septic cardiomyopathy.

Perioperative "remote" acute lung injury: recent update

Perioperative acute lung injury (ALI) is a syndrome characterised by hypoxia and chest radiograph changes. It is a serious post-operative complication, associated with considerable mortality and morbidity. In addition to mechanical ventilation, remote organ insult could also trigger systemic responses which induce ALI. Currently, there are limited treatment options available beyond conservative respiratory support. However, increasing understanding of the pathophysiology of ALI and the biochemical pathways involved will aid the development of novel treatments and help to improve patient outcome as well as to reduce cost to the health service. In this review we will discuss the epidemiology of peri-operative ALI; the cellular and molecular mechanisms involved on the pathological process; the clinical considerations in preventing and managing perioperative ALI and the potential future treatment options.

Vasoactive agents for the treatment of sepsis

The article describes some commonly used vasoactive agents in patients with septic shock. Depending on their distinct pharmacological properties, their effects on vascular bed and cardiac function are different. For example, dopamine has equivalent effect on heart and vasculature, which can result in increases in cardiac output, mean arterial pressure and heart rate. Dobutamine is considered as inodilator because it has potent effect on cardiac systole and vasculature. Patients with sepsis and septic shock sometimes have coexisting cardiac dysfunction that justifies the use of dobutamine. Levosimendan is a relatively new agent exerting its inodilator effect by increasing sensitivity of myocardium to calcium. Some preliminary studies showed a promising result of levosimendan on reducing mortality.

Levosimendan beyond inotropy and acute heart failure: Evidence of pleiotropic effects on the heart and other organs: An expert panel position paper

Levosimendan is a positive inotrope with vasodilating properties (inodilator) indicated for decompensated heart failure (HF) patients with low cardiac output. Accumulated evidence supports several pleiotropic effects of levosimendan beyond inotropy, the heart and decompensated HF. Those effects are not readily explained by cardiac function enhancement and seem to be related to additional properties of the drug such as anti-inflammatory, anti-oxidative and anti-apoptotic ones. Mechanistic and proof-of-concept studies are still required to clarify the underlying mechanisms involved, while properly designed clinical trials are warranted to translate preclinical or early-phase clinical data into more robust clinical evidence. The present position paper, derived by a panel of 35 experts in the field of cardiology, cardiac anesthesiology, intensive care medicine, cardiac physiology, and cardiovascular pharmacology from 22 European countries, compiles the existing evidence on the pleiotropic effects of levosimendan, identifies potential novel areas of clinical application and defines the corresponding gaps in evidence and the required research efforts to address those gaps.