Circulating substances and energy metabolism in septic shock

Effect of landiolol on sex-related transcriptomic changes in the myocardium during sepsis

Objectives

The aims of this study are to better understand phenotypic differences between male and female rats during sepsis, to characterise the contribution of the beta1-adrenergic blocker landiolol to septic cardiomyopathy and to determine why landiolol induces divergent effects in males and females.

Methods

The myocardial transcriptional profiles in male and female Wistar rats were assessed after the induction of sepsis by cecal ligation and puncture and addition of landiolol.

Results

Our results showed major differences in the biological processes activated during sepsis in male and female rats. In particular, a significant decrease in processes related to cell organisation, contractile function, ionic transport and phosphoinositide-3-kinase/AKT (PI3K/AKT) signalling was observed only in males. The transcript of ATPase sarcoplasmic/endoplasmic reticulum Ca²⁺ transporting 3 (SERCA3) was sex-differently regulated. In males, landiolol reversed several signalling pathways dysregulated during sepsis. The expression level of genes encoding tubulin alpha 8 (TUBA8) and myosin heavy chain 7B (MYH7) contractile proteins, phosphatase 2 catalytic subunit alpha (PPP2CA), G protein-coupled receptor kinase 5 (GRK5) and A-kinase anchoring protein 6 (AKAP6) returned to their basal levels. In contrast, in females, landiolol had limited effects.

Conclusion

In males, landiolol reversed the expression of many genes that were deregulated in sepsis. Conversely, sepsis-induced deregulation of gene expression was less pronounced in females than in males, and was maintained in the landiolol-treated females. These findings highlight important sex-related differences and confirm previous observations on the important benefit of landiolol intake on cardiac function in male rats.

Electronic supplementary material

The online version of this article (10.1186/s40635-019-0263-0) contains supplementary material, which is available to authorized users.

Widespread Down-Regulation of Cardiac Mitochondrial and Sarcomeric Genes in Patients With Sepsis

OBJECTIVES

The mechanism(s) for septic cardiomyopathy in humans is not known. To address this, we measured messenger RNA alterations in hearts from patients who died from systemic sepsis, in comparison to changed messenger RNA expression in nonfailing and failing human hearts.

DESIGN

Identification of genes with altered abundance in septic cardiomyopathy, ischemic heart disease, or dilated cardiomyopathy, in comparison to nonfailing hearts.

SETTING

ICUs at Barnes-Jewish Hospital, St. Louis, MO.

PATIENTS

Twenty sepsis patients, 11 ischemic heart disease, nine dilated cardiomyopathy, and 11 nonfailing donors.

INTERVENTIONS

None other than those performed as part of patient care.

MEASUREMENTS AND MAIN RESULTS

Messenger RNA expression levels for 198 mitochondrially localized energy production components, including Krebs cycle and electron transport genes, decreased by 43% ± 5% (mean ± SD). Messenger RNAs for nine genes responsible for sarcomere contraction and excitation-contraction coupling decreased by 43% ± 4% in septic hearts. Surprisingly, the alterations in messenger RNA levels in septic cardiomyopathy were both distinct from and more profound than changes in messenger RNA levels in the hearts of patients with end-stage heart failure.

CONCLUSIONS

The expression profile of messenger RNAs in the heart of septic patients reveals striking decreases in expression levels of messenger RNAs that encode proteins involved in cardiac energy production and cardiac contractility and is distinct from that observed in patients with heart failure. Although speculative, the global nature of the decreases in messenger RNA expression for genes involved in cardiac energy production and contractility suggests that these changes may represent a short-term adaptive response of the heart in response to acute change in cardiovascular homeostasis.

Mechanisms of cardiac and renal dysfunction in patients dying of sepsis

RATIONALE

The mechanistic basis for cardiac and renal dysfunction in sepsis is unknown. In particular, the degree and type of cell death is undefined.

OBJECTIVES

To evaluate the degree of sepsis-induced cardiomyocyte and renal tubular cell injury and death.

METHODS

Light and electron microscopy and immunohistochemical staining for markers of cellular injury and stress, including connexin-43 and kidney-injury-molecule-1 (Kim-1), were used in this study.

MEASUREMENTS AND MAIN RESULTS

Rapid postmortem cardiac and renal harvest was performed in 44 septic patients. Control hearts were obtained from 12 transplant and 13 brain-dead patients. Control kidneys were obtained from 20 trauma patients and eight patients with cancer. Immunohistochemistry demonstrated low levels of apoptotic cardiomyocytes (<1-2 cells per thousand) in septic and control subjects and revealed redistribution of connexin-43 to lateral membranes in sepsis (P < 0.020). Electron microscopy showed hydropic mitochondria only in septic specimens, whereas mitochondrial membrane injury and autophagolysosomes were present equally in control and septic specimens. Control kidneys appeared relatively normal by light microscopy; 3 of 20 specimens showed focal injury in approximately 1% of renal cortical tubules. Conversely, focal acute tubular injury was present in 78% of septic kidneys, occurring in 10.3 ± 9.5% and 32.3 ± 17.8% of corticomedullary-junction tubules by conventional light microscopy and Kim-1 immunostains, respectively (P < 0.01). Electron microscopy revealed increased tubular injury in sepsis, including hydropic mitochondria and increased autophagosomes.

CONCLUSIONS

Cell death is rare in sepsis-induced cardiac dysfunction, but cardiomyocyte injury occurs. Renal tubular injury is common in sepsis but presents focally; most renal tubular cells appear normal. The degree of cell injury and death does not account for severity of sepsis-induced organ dysfunction.

Clinical implications of cytokines in the critical-care unit

To understand the role of different cytokines in the pathophysiology and management of different acute cardiovascular disorders in critically ill patients, we reviewed most of the pertinent articles published on Medline, Scopus and EBSCO host research databases from 1985 to January 2009. We used the indexing terms 'cytokines', 'cardiovascular', 'sepsis', 'critical care', 'myocardial dysfunction', 'shock', 'thromboembolism', 'inflammatory' and 'arrhythmias'. Myocardial dysfunction, dysrhythmic and thromboembolic disorders all appear associated with important fluctuations in cytokines. When and how to sample cytokine levels and the ways in which cytokines contribute to patient deterioration or improvement require further clinical studies. The measurement and interplay of several different cytokines may ultimately be of substantial clinical importance in the diagnosis, treatment and prognosis of patients with different acute cardiovascular disorders managed by critical-care physicians in intensive-care units. Although the role of cytokines in cardiovascular disorders is debatable, the clinical implication of cytokines in the critical-care unit is a new horizon that warrants more attention.

Cytokines and myocardial dysfunction: state of the art

BACKGROUND

Myocardial dysfunction has been associated with inflammation and cytokine modulation.

OBJECTIVES

The study objective was to understand the role of cytokines in the pathophysiology and management of myocardial dysfunction.

METHODS

Heart failure has been revisited with revision of the pertinent published articles in the Medline, Scopus, Cochrane Database of Systematic Reviews, and EBSCO Host research.

RESULTS

For the proinflammatory cytokines, illumination of this important point requires further diagnostic and therapeutic investigations. Data on chronic heart failure are not so reassuring; therefore, patients with advanced heart failure should not be treated with anticytokines at this time.

CONCLUSION

Further studies are warranted to pave the way for introducing cytokine and immunomodulation therapy at the optimal and appropriate time.

Metabolic alterations in sepsis and vasoactive drug-related metabolic effects

The main clinical characteristics of sepsis and septic shock are derangements of cardiocirculatory and respiratory function. Additionally, profound alterations in metabolic pathways occur leading to hypermetabolism, enhanced energy expenditure, and insulin resistance. The clinical hallmarks are hyperglycemia, hyperlactatemia, and enhanced protein catabolism. These metabolic alterations are even more pronounced during sepsis as a result of cytokine release and subsequent induction of inflammatory pathways. Increased oxygen demands from mitochondrial oxygen utilization and oxygen consumption related to oxygen radical formation may contribute to hypermetabolism. In addition, mitochondrial dysfunction with impaired cellular respiration may be present. Mainstay therapeutic interventions for hemodynamic stabilization are adequate volume resuscitation and vasoactive agents, which, however, have additional impact on metabolic activity. Therefore, beyond hemodynamic effects, specific drug-related metabolic alterations need to be considered for optimal treatment during sepsis. This review gives an overview of the typical metabolic alterations during sepsis and septic shock and highlights the impact of vasoactive therapy on metabolism.