Sex-Mediated Response to the Beta-Blocker Landiolol in Sepsis: An Experimental, Randomized Study

Effect of ultrashort-acting β-blockers on 28-day mortality in patients with sepsis with persistent tachycardia despite initial resuscitation: a meta-analysis of randomized controlled trials and trial sequential analysis

Purpose

This meta-analysis aims to identify whether patients with sepsis who have persistent tachycardia despite initial resuscitation can benefit from ultrashort-acting β-blockers.

Materials and methods

Relevant studies from MEDLINE, the Cochrane Library, and Embase were searched by two independent investigators. RevMan version 5.3 (Cochrane Collaboration) was used for statistical analysis.

Results

A total of 10 studies were identified and incorporated into the meta-analysis. The results showed that the administration of ultrashort-acting β-blockers (esmolol/landiolol) in patients with sepsis with persistent tachycardia despite initial resuscitation was significantly associated with a lower 28-day mortality rate (risk ratio [RR], 0.73; 95% confidence interval [CI], 0.57-0.93; and p˂0.01). Subgroup analysis showed that the administration of esmolol in patients with sepsis was significantly associated with a lower 28-day mortality rate (RR, 0.68; 95% CI, 0.55-0.84; and p˂0.001), while there was no significant difference between the landiolol and control groups (RR, 0.98; 95% CI, 0.41-2.34; and p = 0.96). No significant differences between the two groups were found in 90-day mortality, mean arterial pressure (MAP), lactate (Lac) level, cardiac index (CI), and troponin I (TnI) at 24 h after enrollment.

Conclusion

The meta-analysis indicated that the use of esmolol in patients with persistent tachycardia, despite initial resuscitation, was linked to a notable reduction in 28-day mortality rates. Therefore, this study advocates for the consideration of esmolol in the treatment of sepsis in cases where tachycardia persists despite initial resuscitation.

Interactions between Gender and Sepsis—Implications for the Future

Sex and gender dimorphisms are found in a large variety of diseases, including sepsis and septic shock which are more prevalent in men than in women. Animal models show that the host response to pathogens differs in females and males. This difference is partially explained by sex polarization of the intracellular pathways responding to pathogen–cell receptor interactions. Sex hormones seem to be responsible for this polarization, although other factors, such as chromosomal effects, have yet to be investigated. In brief, females are less susceptible to sepsis and seem to recover more effectively than males. Clinical observations produce more nuanced findings, but men consistently have a higher incidence of sepsis, and some reports also claim higher mortality rates. However, variables other than hormonal differences complicate the interaction between sex and sepsis, including comorbidities as well as social and cultural differences between men and women. Conflicting data have also been reported regarding sepsis-attributable mortality rates among pregnant women, compared with non-pregnant females. We believe that unraveling sex differences in the host response to sepsis and its treatment could be the first step in personalized, phenotype-based management of patients with sepsis and septic shock.

Sex-specific differences in cardiac function, inflammation and injury during early polymicrobial sepsis

BACKGROUND

Sex differences in sepsis are underexplored and incompletely understood. Cardiac function in early sepsis is pivotal in determining survival; hyperdynamic left ventricular ejection fraction is associated with higher mortality. Female sex may be cardioprotective, but variable experimental findings have not controlled for hypovolaemia. Sex-specific local cardiac versus peripheral inflammation in causing cardiovascular dysfunction also remain unclear. We therefore examined whether there are sex-specific differences in cardiac function in early sepsis, controlling for volaemic status and sex-specific differences in the peripheral inflammatory response initiated by tumour necrosis factor (TNFα).

METHODS

We used an experimental polymicrobial sepsis (faecal slurry) model titrated to minimise hypovolaemia as a confounding factor. We quantified cardiac function (transthoracic cardiac echocardiography) 1 week before, and 18 h after, sepsis. Cardiac injury (troponin I), inflammation and immune cell infiltration (flow cytometry) were quantified in naïve and septic female and male mice 18 h after sepsis. To evaluate the sex-specific influence of TNFα derived from peripheral leukocytes, we repeated the experiments in iRHOM2^-/- mice that are unable to shed TNFα exclusively from circulating leucocytes.

RESULTS

Serum troponin I increased to 1.39 ± 0.38 ng mL^-1 (from undetectable levels in controls) 18 h after onset of normovolaemic sepsis to a similar extent in both sexes. Stroke volume in male mice increased by 8 µL [(3-13); p = 0.004], compared to individualised pre-sepsis values. By contrast, stroke volume remained at baseline levels in females [mean difference: 4 µL (- 1 to 9)]. Messenger RNA levels of markers for cardiac injury/inflammation after sepsis (real-time polymerase-chain reaction) were elevated in male wild-type mice compared to female wild types (n = 10/sex), with higher cardiac mRNA levels of atrial natriuretic peptide, inflammation (TNFα) and oxidative stress (superoxide dismutase-1), although serum troponin I values were similarly elevated. Flow cytometry analysis of cardiac tissue showed doubling of CD4 + leukocyte infiltration in male mice. Sex-specific cardiac physiologic differences were similar in iRHOM2^-/- mice that are unable to shed TNFα exclusively from leucocytes.

CONCLUSIONS

In early normovolaemic polymicrobial sepsis, a relative hyperdynamic response develops in male mice. Myocardial stress/injury after early sepsis is limited in females, with less cardiac infiltration of CD4 + leukocytes but independent of shedding of TNFα from peripheral circulating leukocytes.

Female hormones prevent sepsis-induced cardiac dysfunction: an experimental randomized study

Although epidemiologic research has demonstrated significant differences in incidence and outcomes of sepsis according to sex, their underlying biological mechanisms are poorly understood. Here, we studied the influence of hormonal status by comparing in vivo cardiac performances measured by MRI in non-ovariectomized and ovariectomized septic female rats. Control and ovariectomized rats were randomly allocated to the following groups: sham, sepsis and sepsis plus landiolol. Sepsis was induced by caecum ligation and punction (CLP). Landiolol, a short-acting selective β1-adrenergic blocker improving the in vivo cardiac performance of septic male rats was perfused continuously after sepsis induction. Cardiac MRI was carried out 18 h after induction of sepsis to assess in vivo cardiac function. Capillary permeability was evaluated by Evans Blue administration and measurement of its tissue extravasation. Variation in myocardial gene and protein expression was also assessed by qPCR and western-blot in the left ventricular tissue. Sepsis reduced indexed stroke volume, cardiac index and indexed end-diastolic volume compared to sham group in ovariectomized females whereas it had no effect in control females. This was associated with an overexpression of JAK2 expression and STAT3 phosphorylation on Ser727 site, and an inhibition of the adrenergic pathways in OVR females. Landiolol increased the indexed stroke volume by reversing the indexed end-diastolic volume reduction after sepsis in ovariectomized females, while it decreased indexed stroke volume and cardiac index in control. This was supported by an overexpression of genes involved in calcium influx in OVR females while an inactivation of the β-adrenergic and a calcium efflux pathway was observed in control females. Sepsis decreased in vivo cardiac performances in ovariectomized females but not in control females, presumably associated with a more pronounced inflammation, inhibition of the adrenergic pathway and calcium efflux defects. Administration of landiolol prevents this cardiac dysfunction in ovariectomized females with a probable activation of calcium influx, while it has deleterious effects in control females in which calcium efflux pathways were down-regulated.

The Effects of Biological Sex on Sepsis Treatments in Animal Models: A Systematic Review and a Narrative Elaboration on Sex- and Gender-Dependent Differences in Sepsis

Preclinical studies provide an opportunity to evaluate the relationship between sex and sepsis, and investigate underlying mechanisms in a controlled experimental environment. The objective of our systematic review was to assess the impact of biological sex on treatment response to fluid and antibiotic therapy in animal models of sepsis. Furthermore, we provide a narrative elaboration of sex-dependent differences in preclinical models of sepsis.

DATA SOURCES

MEDLINE and Embase were searched from inception to March 16, 2020.

STUDY SELECTION

All studies reporting sex-stratified data comparing antibiotics and/or fluid resuscitation with a placebo or no treatment arm in an in vivo model of sepsis were included.

DATA EXTRACTION

Outcomes of interest were mortality (primary) and organ dysfunction (secondary). Risk of bias was assessed. Study selection and data extraction were conducted independently and in duplicate.

DATA SYNTHESIS

The systematic search returned 2,649 unique studies, and two met inclusion criteria. Both studies used cecal ligation and puncture models with imipenem/cilastatin antibiotics. No eligible studies investigated fluids. In one study, antibiotic therapy significantly reduced mortality in male, but not female, animals. The other study reported no sex differences in organ dysfunction. Both studies were deemed to be at a high overall risk of bias.

CONCLUSIONS

There is a remarkable and concerning paucity of data investigating sex-dependent differences in fluid and antibiotic therapy for the treatment of sepsis in animal models. This may reflect poor awareness of the importance of investigating sex-dependent differences. Our discussion therefore expands on general concepts of sex and gender in biomedical research and sex-dependent differences in key areas of sepsis research such as the cardiovascular system, immunometabolism, the microbiome, and epigenetics. Finally, we discuss current clinical knowledge, the potential for reverse translation, and directions for future studies.

REGISTRATION

PROSPERO CRD42020192738.

Sex Differences of the Diabetic Heart

Type 2 diabetes is a chronic disease associated with micro- and macro-vascular complications, including myocardial ischemia, and also with a specific and intrinsic cardiac dysfunction called diabetic cardiomyopathy (DCM). Both clinical and animal studies demonstrate significant sex differences in prevalence, pathophysiology, and outcomes of cardiovascular diseases (CVDs), including those associated with diabetes. The increased risk of CVDs with diabetes is higher in women compared to men with 50% higher risk of coronary artery diseases and increased mortality when exposed to acute myocardial infarction. Clinical studies also reveal a sexual dimorphism in the incidence and outcomes of DCM. Based on these clinical findings, growing experimental research was initiated to understand the impact of sex on CVDs associated with diabetes and to identify the molecular mechanisms involved. Endothelial dysfunction, atherosclerosis, coagulation, and fibrosis are mechanisms found to be sex-differentially modulated in the diabetic cardiovascular system. Recently, impairment of energy metabolism also emerged as a determinant of multiple CVDs associated with diabetes. Therefore, future studies should thoroughly analyze the sex-specific metabolic determinants to propose new therapeutic targets. With current medicine tending toward more personalized care of patients, we finally propose to discuss the importance of sex as determinant in the treatment of diabetes-associated cardiac diseases to promote a more systemic inclusion of both males and females in clinical and preclinical studies.

Pralidoxime improves the hemodynamics and survival of rats with peritonitis-induced sepsis

Several studies have suggested that sympathetic overstimulation causes deleterious effects in septic shock. A previous study suggested that pralidoxime exerted a pressor effect through a mechanism unrelated to the sympathetic nervous system; this effect was buffered by the vasodepressor action of pralidoxime mediated through sympathoinhibition. In this study, we explored the effects of pralidoxime on hemodynamics and survival in rats with peritonitis-induced sepsis. This study consisted of two sub-studies: survival and hemodynamic studies. In the survival study, 66 rats, which survived for 10 hours after cecal ligation and puncture (CLP), randomly received saline placebo, pralidoxime, or norepinephrine treatment and were monitored for up to 24 hours. In the hemodynamic study, 44 rats were randomly assigned to sham, CLP-saline placebo, CLP-pralidoxime, or CLP-norepinephrine groups, and hemodynamic measurements were performed using a conductance catheter placed in the left ventricle. In the survival study, 6 (27.2%), 15 (68.1%), and 5 (22.7%) animals survived the entire 24-hour monitoring period in the saline, pralidoxime, and norepinephrine groups, respectively (log-rank test P = 0.006). In the hemodynamic study, pralidoxime but not norepinephrine increased end-diastolic volume (P <0.001), stroke volume (P = 0.002), cardiac output (P = 0.003), mean arterial pressure (P = 0.041), and stroke work (P <0.001). The pressor effect of norepinephrine was short-lived, such that by 60 minutes after the initiation of norepinephrine infusion, it no longer had any significant effect on mean arterial pressure. In addition, norepinephrine significantly increased heart rate (P <0.001) and the ratio of arterial elastance to ventricular end-systolic elastance (P = 0.010), but pralidoxime did not. In conclusion, pralidoxime improved the hemodynamics and 24-hour survival rate in rats with peritonitis-induced sepsis, but norepinephrine did not.

Sex difference in sympathetic nervous system activity and blood pressure in hypertensive patients

Increased sympathetic nervous system (SNS) activity leads to increased risk of cardiovascular morbidity and mortality. This study investigated whether there were sex differences in SNS activity among Chinese patients with hypertension. Ethnic Chinese non‐diabetic hypertensive patients aged 20–50 years were enrolled in Taiwan. A total of 970 hypertensive patients (41.0 ± 7.2 years) completed the study, 664 men and 306 women. They received comprehensive evaluations including office blood pressure (BP) measurement, 24‐h ambulatory BP monitoring, and 24‐h urine sampling assayed for catecholamine excretion. Compared to women, men were younger, had higher body mass index (BMI), office systolic BP (SBP), office diastolic BP (DBP), 24‐h ambulatory BP, and 24‐h urine catecholamine excretion. In men, 24‐h urine total catecholamine levels were correlated with 24‐h SBP (r = 0.103, p = .008) and 24‐h DBP (r = 0.083, p = .033). In women, however, there was no correlation between 24‐h urine total catecholamine levels and 24‐h ambulatory BP. Multivariate linear regression indicated that being male (β = 1.65, 95% confidence interval [CI] 0.01–3.29, p = .048) and 24‐h urine total catecholamine (β = 5.03, 95% CI 0.62–9.44, p = .025) were both independently associated with 24‐h SBP; being male was independently associated with 24‐h DBP (β = 3.55, 95% CI 2.26–4.85, p < .001). In conclusion, Chinese men with hypertension had higher SNS activity than women, and SNS activity was independently associated with 24‐h ambulatory BP in men rather than in women. These findings suggest that different hypertensive treatment strategies should be considered according to patient sex.

Evaluating the Therapeutic Efficacy and Safety of Landiolol Hydrochloride for Management of Arrhythmia in Critical Settings: Review of the Literature

Background

Landiolol hydrochloride, a highly cardio-selective beta-1 blocker with an ultra-short-acting half-life of 4 minutes, was originally approved by Japan for treatment of intraoperative tachyarrhythmias. This review aims to provide an integrated overview of the current state of knowledge of landiolol hydrochloride in the management of arrhythmia in critical settings.

Methods

We searched MEDLINE, EMBASE, and the Cochrane Library to retrieve relevant articles with a total of 65 records identified.

Results

The high β1 selectivity (β1/β2 ratio of 255:1) of landiolol causes a more rapid heart rate (HR) decrease compared to esmolol while avoiding decreases in mean arterial blood pressure. Recently, it has been found useful in left ventricular dysfunction patients and fatal arrhythmia requiring emergency treatment. Recent random clinical trials (RCT) have revealed therapeutic and prophylactic effects on arrhythmia, and very low-dose landiolol might be effective for preventing postoperative atrial fibrillation (POAF) and sinus tachycardia. Likewise, landiolol is an optimal choice for perioperative tachycardia treatment during cardiac surgery. The high β1 selectivity of landiolol is useful in heart failure patients as a first-line therapy for tachycardia and arrhythmia as it avoids the typical depression of cardiac function seen in other β-blockers. Application in cardiac injury after percutaneous coronary intervention (PCI), protection for vital organs (lung, kidney, etc.) during sepsis, and stabilizing hemodynamics in pediatric patients are becoming the new frontier of landiolol use.

Conclusion

Landiolol is useful as a first-line therapy for the prevention of POAF after cardiac/non-cardiac surgery, fatal arrhythmias in heart failure patients and during PCI. Moreover, the potential therapeutic effect of landiolol for sepsis in pediatric patients is currently being explored. As positive RCT results continue to be published, new clinical uses and further clinical studies in various settings by cardiologists, intensivists and pediatric cardiologists are being conducted.

β-Blockade attenuates renal blood flow in experimental endotoxic shock by reducing perfusion pressure

Clinical data suggests that heart rate (HR) control with selective β1-blockers may improve cardiac function during septic shock. However, it seems counterintuitive to start β-blocker infusion in a shock state when organ blood flow is already low or insufficient. Therefore, we studied the effects of HR control with esmolol, an ultrashort- acting β1-selective adrenoceptor antagonist, on renal blood flow (RBF) and renal autoregulation during early septic shock. In 10 healthy sheep, sepsis was induced by continuous i.v. administration of lipopolysaccharide, while maintained under anesthesia and mechanically ventilated. After successful resuscitation of the septic shock with fluids and vasoactive drugs, esmolol was infused to reduce HR with 30% and was stopped 30-min after reaching this target. Arterial and venous pressures, and RBF were recorded continuously. Renal autoregulation was evaluated by the response in RBF to renal perfusion pressure (RPP) in both the time domain and frequency domain. During septic shock, β-blockade with esmolol significantly increased the pressure dependency of RBF to RPP. Stopping esmolol showed the reversibility of the impaired renal autoregulation. Showing that clinical diligence and caution are necessary when treating septic shock with esmolol in the acute phase since esmolol reduced RPP to critical values thereby significantly reducing RBF.

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.

β-bloquants dans la prise en charge du choc septique

Les adrénorécepteurs α et en particulier β sont les principales cibles de l’adrénaline et de la noradrénaline libérées par le système sympathique activé. Durant le choc septique, la dysautonomie est une stimulation prolongée à un haut niveau d’intensité du système nerveux sympathique à l’origine d’une altération de la contractilité, de la vasoréactivité et d’une immunodépression. Ainsi, l’administration précoce d’un traitement β-bloquant lors du choc septique pourrait pondérer les effets délétères de cette surstimulation sympathique. Néanmoins, si les preuves expérimentales sont en faveur de cette approche, l’accumulation des preuves cliniques reste encore insuffisante.

Hemodynamic response to β-blockers in severe sepsis and septic shock: A review of current literature

The administration of β-blockers in patients with sepsis is a trending topic in intensive care medicine since the landmark study by Morelli and colleagues, showing a striking decrease in 28-day mortality compared to standard care. While the available evidence suggests that the use of β-blockers in septic shock is safe, the effects on hemodynamics are controversial. In this paper, we review the effect of β-blockade in septic shock on hemodynamics from animal models to critically ill patients.

Sex and bacterial infectious diseases

Most infectious diseases are unequally distributed between male and female subjects. This sex dimorphism is confirmed by epidemiologic studies which suggest an increased number of male septic patients, while, due to the class age of septic patients, an overrepresentation of female patients would be expected. Lifestyle, recreational activities, professional exposition and access to care are plausible reasons for this dimorphism. However, biological differences should be carefully considered, particularly the weight of X-linked variability and the role of sex hormones. Animal models clearly show that clinical response to infection is more exuberant in males than in females. This is partly explained by an attenuation of the inflammatory response by female sex hormones. However, the translation from experimental studies to the bedside remains challenging as a result of confounding factors like age, hormone changes and response to treatment.