Vasoplegia in patients with sepsis and septic shock: pathways and mechanisms

Vascular Reactivity Index as an Effective Predictor of Mortality in Patients With Septic Shock: A Retrospective Study

BACKGROUND

Sepsis is a serious complication that occurs after trauma, burns, and infections, and it is an important cause of death in intensive care unit (ICU) patients. Despite many new measures being proposed for sepsis treatment, its mortality rate remains high; sepsis has become a serious threat to human health, and there is an urgent need to carry out in-depth clinical research related to sepsis. In recent years, it has been found that septic shock-induced vasoplegia is a result of vascular hyporesponsiveness to vasopressors. Therefore, this study intended to establish an objective formula related to vasoplegia that can be used to assess the prognosis of patients and guide clinical treatment.

MATERIALS AND METHODS

A retrospective cohort study was conducted using data from 106 septic shock patients admitted to the ICU of Jining No. 1 People's Hospital from January 2020 to December 2022. The patients were divided into mortality and survival groups based on 28-day survival, and hemodynamics were monitored by the pulse index continuous cardiac output system. The dose and duration of vasopressors, major hemodynamic parameters, lactic acid (Lac) levels, and Sequential Organ Failure Assessment scores were recorded within 48 h of hospital admission. Multifactorial logistic regression was used to analyze the independent risk factors affecting the prognosis of patients, and the predictive value of the vascular response index (VRI) was analyzed by the receiver operating characteristic (ROC) curve.

RESULTS

The differences between the survival and mortality groups in terms of age, sex ratio, body weight, ICU length of stay, distribution of infection sites, underlying disease conditions, baseline Lac levels, and some hemodynamic parameters were not statistically significant (P > .05). The results of multifactorial logistic regression showed that the admission Acute Physiology and Chronic Health Evaluation II score, Lac level at 24 h of treatment, maximal vasoactive inotropic score at 24 h (VISmax24), maximal vasoactive inotropic score at 48 h (VISmax48), and VRI were independent risk factors affecting 28-day mortality. Within 48 h of receiving vasopressor therapy, the VRI was lower in the mortality group than in the survival group. The area under the ROC curve for the VRI was 0.86, and the best cutoff value of the VRI for predicting 28-day mortality was 32.50 (YI = 0.80), with a sensitivity of 0.90, a specificity of 0.90, and a better prediction of mortality than the other indicators.

CONCLUSIONS

The VRI is a good predictor of mortality in patients with septic shock, and a lower VRI indicates more severe vasoplegia, poorer prognosis, and higher mortality in patients with septic shock.

The Use of Methylene Blue in Conjunction With Hydroxocobalamin and Multiple Pressors to Treat Severe Vasoplegia in a Patient Due to Calcium Channel Blocker Toxicity: A Case Report

Vasoplegia, the demonstration of persistently low systemic vascular resistance (SVR) and resistant hypotension in the presence of a normal cardiac index despite aggressive resuscitation attempts, is a serious clinical diagnosis that requires prompt treatment to prevent patient morbidity and mortality. Currently, treatment of vasoplegia involves treatment with vasopressors such as vasopressin, norepinephrine, and hydroxocobalamin. However, some evidence suggests that in addition to this treatment regimen, the addition of methylene blue may result in a reduction in overall norepinephrine equivalent vasopressor requirements, increased mean arterial pressure, and an improved clinical course. Here, we report the case of a 64-year-old male patient who presented to the ED after being found unresponsive and covered in emesis at home. The patient's presentation was complicated by worsening dyspnea, hypotension, and hemodynamic instability, requiring intubation and admission to the ICU for management of undifferentiated shock of unclear etiology and acute respiratory failure. Urine studies were consistent with a diagnosis of vasoplegia due to dihydropyridine calcium channel blocker toxicity, which was confirmed by pill counting of his home medications in the setting of recent paranoia and depression. The patient was treated aggressively with vasopressors, including vasopressin, phenylephrine, and epinephrine, as well as a combination of hydroxocobalamin and methylene blue. He was also started on a calcium and insulin drip. Upon initiation of non-catecholamine agents for vasoplegia, his clinical course quickly improved, and he was weaned from all vasopressors. He regained hemodynamic stability, was successfully extubated, evaluated by psychiatry, and discharged from the hospital in a stable condition on day 15 with the continuation of outpatient psychiatric services.

Oral anticoagulants increased 30-day survival in sepsis patients complicated with atrial fibrillation: a retrospective analysis from MIMIC-IV database

Background

The severity of sepsis is associated with systemic clotting activation. Atrial fibrillation (AF) is the most commonly observed arrhythmia in patients with sepsis and can lead to a poor prognosis. The aim of this study is to elucidate the association between oral anticoagulants and survival from septic patients complicated with AF.

Methods

The data of 8,828 septic patients, including 2,955 AF and 5,873 without AF, were all originated from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Patients with sepsis and AF are divided into OAC- group (n = 1,774) and OAC+ group (n = 1,181) based on OAC therapy. Septic patients with no AF were considered as the control group (n = 5,873, sepsis and no AF group). The main outcome endpoint was the survival rate of 30 day. The secondary outcome endpoint was the length of stay (LOS) from intensive care unit and hospital. Propensity score matching (PSM) was used to adjust the influence of superfluous factors, and a restricted mean survival time (RMST) analysis was used for calculating the benefit of survival time and survival rate. Analysis including univariate and multivariate logistic regression analysis was conducted to find prognosis-related predictors.

Results

After PSM, the OAC+group had a higher 30-day survival rate compared to the OAC- group (81.59% vs. 58.10%; P < 0.001) in the ICU. Despite the higher survival, the hospital LOS (14.65 days vs. 16.66 days; P = 0.15) and ICU LOS (6.93 days vs. 5.92 days; P = 0.02) were prolonged at OAC+ group than OAC- group. No difference was found in survival rate of 30 day between the sepsis patients using warfarin and patients using NOAC (85.60% vs. 79.84%, P = 0.12). The sepsis patients using warfarin had a prolonged LOS in ICU and hospital compared with the sepsis patients using NOAC. In the vasopressor subgroup, patients who received NOAC therapy were associated with a reduced 30-day survival rate (73.57% vs. 84.03%; P = 0.04) and reduced LOS in ICU and hospital than those on warfarin therapy.

Conclusion

This study demonstrated that oral anticoagulants may increase the 30-day survival rate of patients with sepsis and AF.

The synergism of cytosolic acidosis and reduced NAD+/NADH ratio is responsible for lactic acidosis-induced vascular smooth muscle cell impairment in sepsis

BACKGROUND

During sepsis, serve vascular dysfunctions lead to life-threatening multiple organ failure, due to vascular smooth muscle cells (VSMC) impairments, resulting in vasoplegia, hypotension and hypoperfusion. In addition, septic patients have an altered cell metabolism that leads to lactic acidosis. Septic patients suffering from lactic acidosis have a high risk of mortality. In addition, septic survivors are at risk of secondary vascular disease. The underlying mechanisms of whether and how lactic acidosis leads to the changes in VSMCs is not well understood. The aim of this study was to comprehensively investigate the effect of lactic acidosis on VSMCs and additionally compare the effects with those induced by pure acidosis and sodium lactate.

METHODS

Primary human aortic smooth muscle cells (HAoSMCs) were treated for 48 h with lactic acidosis (LA_pH 6.8), hydrochloric acid (HCl_pH 6.8), sodium lactate (Na+-lactate_pH 7.4) and the respective controls (ctrl._pH 7.4; hyperosmolarity control: mannitol_pH 7.4) and comparatively analyzed for changes in (i) transcriptome, (ii) energy metabolism, and (iii) phenotype.

RESULTS

Both types of acidosis led to comparable and sustained intracellular acidification without affecting cell viability. RNA sequencing and detailed transcriptome analysis revealed more significant changes for lactic acidosis than for hydrochloric acidosis, with lactate being almost ineffective, suggesting qualitative and quantitative synergism of acidosis and lactate. Bioinformatic predictions in energy metabolism and phenotype were confirmed experimentally. Lactic acidosis resulted in strong inhibition of glycolysis, glutaminolysis, and altered mitochondrial respiration which reduced cellular ATP content, likely due to increased TXNIP expression and altered NAD+/NADH ratio. Hydrochloric acidosis induced significantly smaller effects without changing the NAD+/NADH ratio, with the ATP content remaining constant. These metabolic changes led to osteo-/chondrogenic/senescent transdifferentiation of VSMCs, with the effect being more pronounced in lactic acidosis than in pure acidosis.

CONCLUSIONS

Overall, lactic acidosis exerted a much stronger effect on energy metabolism than pure acidosis, whereas lactate had almost no effect, reflecting the qualitative and quantitative synergism of acidosis and lactate. As a consequence, lactic acidosis may lead to acute functional impairments of VSMC, sustained perturbations of the transcriptome and cellular dedifferentiation. Moreover, these effects may contribute to the acute and prolonged vascular pathomechanisms in septic patients.

Severe Refractory Vasoplegic Shock Syndrome after OPCABG Successfully Treated with Hydroxycobalamin: A Case Report and Review of the Literature

BACKGROUND

Vasoplegic shock syndrome (VSS) after an off-pump coronary artery bypass graft (OPCABG) is an extremely rare condition. Inotropic support is usually the first-line therapy, though it can precipitate several complications or be ineffective. We report the first case of severe refractory VSS after OPCABG successfully treated with hydroxycobalamin.

METHODS

A 77-year-old gentleman underwent OPCABG for three vessels coronary artery disease. Preoperative LV ejection fraction was 28%, and the patient before surgery started sacubitril/valsartan titrated, then, at the highest dose. Surgery was uneventful and, by the end of the procedure, TEE showed improved biventricular contractility.

RESULTS

The patient was transferred to the ICU without inotropic support, but soon developed hypotension. TEE ruled out pericardial tamponade and confirmed fair contractility. Norepinephrine was titrated to a medium-high dose, vasopressin was started and a Swan-Ganz catheter was placed. SVR was 480 dyn·s·cm-5. Despite aggressive pharmacologic treatment (including methylprednisolone and methylene blue), no improvements were noticed. Ten grams of hydroxycobalamin were administered. One hour later, hemodynamic status re-assessment showed SVR > 800 dyn·s·cm-5. Afterward, vasopressors were gradually reduced.

CONCLUSIONS

Our case demonstrated the importance of adequate early treatment in VSS after OPCABG. This case report shows, for the first time, that hydroxycobalamin was effectively used to restore homeostasis.

Micro-lightguide spectrophotometry assessment of hepatic and intestinal microcirculation in endotoxemic rats during intravenous treatment with angiotensin II

INTRODUCTION

During septic shock, impairment of microcirculation leads to enhanced permeability of intestinal mucosa triggered by generalized vasodilation and capillary leak. Intravenous angiotensin II (AT-II) has been approved for the treatment of septic shock; however, no in-vivo data exist on the influence of AT-II on hepatic and intestinal microcirculation.

MATERIAL AND METHODS

Sixty male Lewis rats were randomly assigned to six study groups (each n = 10): sham, lipopolysaccharide-induced septic shock, therapy with low- or high-dose AT-II (50 or 100 ng/kg/min, respectively), and septic shock treated with low- or high-dose AT-II. After median laparotomy, hepatic and intestinal microcirculation measures derived from micro-lightguide spectrophotometry were assessed for 3 h and included oxygen saturation (SO2), relative blood flow (relBF) and relative hemoglobin level (relHb). Hemodynamic measurements were performed using a left ventricular conductance catheter, and blood samples were taken hourly to analyze blood gasses and systemic cytokines.

RESULTS

AT-II increased mean arterial pressure in a dose-dependent manner in both septic and non-septic animals (p < 0.001). Lower hepatic and intestinal SO2 (both p < 0.001) were measured in animals without endotoxemia who received high-dose AT-II treatment, however, significantly impaired cardiac output was also reported in this group (p < 0.001). In endotoxemic rats, hepatic relBF and relHb were comparable among the treatment groups; however, hepatic SO2 was reduced during low- and high-dose AT-II treatment (p < 0.001). In contrast, intestinal SO2 remained unchanged despite treatment with AT-II. Intestinal relBF (p = 0.028) and interleukin (IL)-10 plasma levels (p < 0.001) were significantly elevated during treatment with high-dose AT-II compared with low-dose AT-II.

CONCLUSIONS

A dose-dependent decrease of hepatic and intestinal microcirculation during therapy with AT-II in non-septic rats was observed, which might have been influenced by a corresponding reduction in cardiac output due to elevated afterload. While hepatic microcirculation was reduced during endotoxemia, no evidence for a reduction in intestinal microcirculation facilitated by AT-II was found. In contrast, both intestinal relBF and anti-inflammatory IL-10 levels were increased during high-dose AT-II treatment.

Atrial fibrillation is not an independent determinant of 28-day mortality among critically III sepsis patients

This study was conducted to investigate the relationship between atrial fibrillation and the clinical prognosis of patients with sepsis in intensive care unit. A total of 21,538 sepsis patients were enrolled in the study based on the Medical Information Mart for Intensive Care IV database, of whom 6,759 had AF. Propensity score matching was used to compare the clinical characteristics and outcomes of patients with and without AF. Besides, the inverse probability of treatment weighting, univariate and multivariate Cox regression analyzes were performed. Of the 21,538 patients, 31.4% had AF. The prevalence of AF increased in a step-by-step manner with growing age. Patients with AF were older than those without AF. After PSM, 11,180 patients remained, comprising 5,790 matched pairs in both groups. In IPTW, AF was not associated with 28-day mortality [hazard ratio (HR), 1.07; 95% confidence interval (CI), 0.99-1.15]. In Kaplan-Meier analysis, it was not observed difference of 28-day mortality between patients with and without AF. AF could be associated with increased ICU LOS, hospital LOS and need for mechanical ventilation; however, it does not remain an independent short-term predictor of 28-day mortality among patients with sepsis after PSM with IPTW and multivariate analysis.

Vasoplegia: A Review

Vasoplegia is a condition characterized by persistent low systemic vascular resistance despite a normal or high cardiac index, resulting in profound and uncontrolled vasodilation. Vasoplegia may occur due to various conditions, including cardiac failure, sepsis, and post-cardiac surgery. In the cardiac cohort, multiple risk factors for vasoplegia have been identified. Several factors contribute to the pathophysiology of this condition, and various mechanisms have been proposed, including nitric oxide, adenosine, prostanoids, endothelins, the renin-angiotensin-aldosterone system, and hydrogen sulfide. Early identification and prompt management of vasoplegia is crucial to prevent development of shock. This review expands upon the different vasopressors used in management of vasoplegia, including catecholamines such as norepinephrine, dopamine, epinephrine, phenylephrine, and other agents including vasopressin, methylene blue, angiotensin II, hydroxocobalamin, vitamin C, thiamine, and corticosteroids (ie, hydrocortisone). It also emphasizes the importance of conducting further research and making advancements in treatment regimens for vasoplegia.

The role of the microcirculation and integrative cardiovascular physiology in the pathogenesis of ICU-acquired weakness

Skeletal muscle dysfunction after critical illness, defined as ICU-acquired weakness (ICU-AW), is a complex and multifactorial syndrome that contributes significantly to long-term morbidity and reduced quality of life for ICU survivors and caregivers. Historically, research in this field has focused on pathological changes within the muscle itself, without much consideration for their in vivo physiological environment. Skeletal muscle has the widest range of oxygen metabolism of any organ, and regulation of oxygen supply with tissue demand is a fundamental requirement for locomotion and muscle function. During exercise, this process is exquisitely controlled and coordinated by the cardiovascular, respiratory, and autonomic systems, and also within the skeletal muscle microcirculation and mitochondria as the terminal site of oxygen exchange and utilization. This review highlights the potential contribution of the microcirculation and integrative cardiovascular physiology to the pathogenesis of ICU-AW. An overview of skeletal muscle microvascular structure and function is provided, as well as our understanding of microvascular dysfunction during the acute phase of critical illness; whether microvascular dysfunction persists after ICU discharge is currently not known. Molecular mechanisms that regulate crosstalk between endothelial cells and myocytes are discussed, including the role of the microcirculation in skeletal muscle atrophy, oxidative stress, and satellite cell biology. The concept of integrated control of oxygen delivery and utilization during exercise is introduced, with evidence of physiological dysfunction throughout the oxygen delivery pathway - from mouth to mitochondria - causing reduced exercise capacity in patients with chronic disease (e.g., heart failure, COPD). We suggest that objective and perceived weakness after critical illness represents a physiological failure of oxygen supply-demand matching - both globally throughout the body and locally within skeletal muscle. Lastly, we highlight the value of standardized cardiopulmonary exercise testing protocols for evaluating fitness in ICU survivors, and the application of near-infrared spectroscopy for directly measuring skeletal muscle oxygenation, representing potential advancements in ICU-AW research and rehabilitation.

Inflammatory mechanisms and intervention strategies for sepsis-induced myocardial dysfunction

Sepsis-induced myocardial dysfunction (SIMD) is the leading cause of death in patients with sepsis in the intensive care units. The main manifestations of SIMD are systolic and diastolic dysfunctions of the myocardium. Despite our initial understanding of the SIMD over the past three decades, the incidence and mortality of SIMD remain high. This may be attributed to the large degree of heterogeneity among the initiating factors, disease processes, and host states involved in SIMD. Previously, organ dysfunction caused by sepsis was thought to be an impairment brought about by an excessive inflammatory response. However, many recent studies have shown that SIMD is a consequence of a combination of factors shaped by the inflammatory responses between the pathogen and the host. In this article, we review the mechanisms of the inflammatory responses and potential novel therapeutic strategies in SIMD.

Combined Multiomics and In Silico Approach Uncovers PRKAR1A as a Putative Therapeutic Target in Multi-Organ Dysfunction Syndrome

Despite all epidemiological, clinical, and experimental research efforts, therapeutic concepts in sepsis and sepsis-induced multi-organ dysfunction syndrome (MODS) remain limited and unsatisfactory. Currently, gene expression data sets are widely utilized to discover new biomarkers and therapeutic targets in diseases. In the present study, we analyzed MODS expression profiles (comprising 13 sepsis and 8 control samples) retrieved from NCBI-GEO and found 359 differentially expressed genes (DEGs), among which 170 were downregulated and 189 were upregulated. Next, we employed the weighted gene co-expression network analysis (WGCNA) to establish a MODS-associated gene co-expression network (weighted) and identified representative module genes having an elevated correlation with age. Based on the results, a turquoise module was picked as our hub module. Further, we constructed the PPI network comprising 35 hub module DEGs. The DEGs involved in the highest-confidence PPI network were utilized for collecting pathway and gene ontology (GO) terms using various libraries. Nucleotide di- and triphosphate biosynthesis and interconversion was the most significant pathway. Also, 3 DEGs within our PPI network were involved in the top 5 significantly enriched ontology terms, with hypercortisolism being the most significant term. PRKAR1A was the overlapping gene between top 5 significant pathways and GO terms, respectively. PRKAR1A was considered as a therapeutic target in MODS, and 2992 ligands were screened for binding with PRKAR1A. Among these ligands, 3 molecules based on CDOCKER score (molecular dynamics simulated-based score, which allows us to rank the binding poses according to their quality and to identify the best pose for each system) and crucial interaction with human PRKAR1A coding protein and protein kinase-cyclic nucleotide binding domains (PKA RI alpha CNB-B domain) via active site binding residues, viz. Val283, Val302, Gln304, Val315, Ile327, Ala336, Ala337, Val339, Tyr373, and Asn374, were considered as lead molecules.

Perioperative changes in fluid distribution and haemodynamics in acute high-risk abdominal surgery

BACKGROUND

Understanding the pathophysiology of fluid distribution in acute high-risk abdominal (AHA) surgery is essential in optimizing fluid management. There is currently no data on the time course and haemodynamic implications of fluid distribution in the perioperative period and the differences between the surgical pathologies.

METHODS

Seventy-three patients undergoing surgery for intestinal obstruction, perforated viscus, and anastomotic leakage within a well-defined perioperative regime, including intraoperative goal-directed therapy, were included in this prospective, observational study. From 0 to 120 h, we measured body fluid volumes and hydration status by bioimpedance spectroscopy (BIA), fluid balance (input vs. output), preload dependency defined as a > 10% increase in stroke volume after preoperative fluid challenge, and post-operatively evaluated by passive leg raise.

RESULTS

We observed a progressive increase in fluid balance and extracellular volume throughout the study, irrespective of surgical diagnosis. BIA measured variables indicated post-operative overhydration in 36% of the patients, increasing to 50% on the 5th post-operative day, coinciding with a progressive increase of preload dependency, from 12% immediately post-operatively to 58% on the 5th post-operative day and irrespective of surgical diagnosis. Patients with overhydration were less haemodynamically stable than those with normo- or dehydration.

CONCLUSION

Despite increased fluid balance and extracellular volumes, preload dependency increased progressively during the post-operative period. Our observations indicate a post-operative physiological incoherence between changes in the extracellular volume compartment and inadequate physiological preload control in patients undergoing AHA surgery. Considering the increasing overhydration during the observational period, our findings show that an indiscriminate correction of preload dependency with intravenous fluid bolus could lead to overhydration. Trial registration clinicaltrials.gov. (NCT03997721), Registered 23 May 2019, first participant enrolled 01 June 2019.

Clinical approach to vasoplegia in the transplant patient from the Pediatric Heart Transplant Society

This manuscript outlines a clinical approach to vasoplegia incorporating the current state of knowledge regarding vasoplegia in pediatric patients immediately post-transplant and to identify modifiable factors both pre- and post-transplant that may reduce post-operative morbidity, end-organ dysfunction, and mortality. Centers participating in the Pediatric Heart Transplant Society (PHTS) were asked to provide their internal protocols and rationale for vasoplegia management, and applicable adult and pediatric data were reviewed. The authors synthesized the above protocols and literature into the following description of clinical approaches to vasoplegia highlighting areas of both broad consensus and of significant practice variation.

Fluids or vasopressors for the initial resuscitation of septic shock

Intravenous fluid resuscitation is recommended first-line treatment for sepsis-associated hypotension and/or hypoperfusion. The rationale is to restore circulating volume and optimize cardiac output in the setting of shock. Nonetheless, there is limited high-level evidence to support this practice. Over the past decade emerging evidence of harm associated with large volume fluid resuscitation among patients with septic shock has led to calls for a more conservative approach. Specifically, clinical trials undertaken in Africa have found harm associated with initial fluid resuscitation in the setting of infection and hypoperfusion. While translating these findings to practice in other settings is problematic, there has been a re-appraisal of current practice with some recommending earlier use of vasopressors rather than repeated fluid boluses as an alternative to restore perfusion in septic shock. There is consequently uncertainty and variation in practice. The question of fluids or vasopressors for initial resuscitation in septic shock is the subject of international multicentre clinical trials.

The Role of Left Ventricular Ejection Fraction and Left Ventricular Outflow Tract Velocity-Time Integral in Assessing Cardiovascular Impairment in Septic Shock

Background: the role of echocardiography in septic shock remains controversial, since depressed cardiac afterload may overestimate left ventricular (LV) systolic performance and mask septic cardiomyopathy (SC). We hypothesized that afterload-adjusted LV ejection fraction (LVEF) and LV outflow tract velocity-time integral (VTI) values for given systemic vascular resistances (SVR) could provide novel insights into recognizing and stratifying the severity of SC. Methods: in this observational, monocentric study, we prospectively included 14 mechanically-ventilated patients under septic-shock who all had a Pulse index Continuous Cardiac Output (PiCCO) system in place for hemodynamic monitoring. Echocardiographic and PiCCO longitudinal examinations (71 measurements overall) were performed simultaneously at the onset of septic shock and every 12 h for 60 h overall. Results: VTI-derived stroke volume (SV) and cardiac output (CO) were significantly correlated with PiCCO measurements (r ≥ 0.993, both p < 0.001). LVEF and VTI showed linear and exponential inverse correlation to SVR (R2 = 0.183 vs. 0.507 and p < 0.001 vs. p < 0.001, respectively). The equations LVEF = 86.168 − 0.011 × SVR and VTI = 41.23 × e(−0.0005×SVR) were found to provide “predicted” values for given SVR. Measured to predicted LVEF ratios (for given SVR), the afterload-adjusted LVEF defined the severity of SC (mild ≥ 90%, 80% ≤ moderate < 90% and severe < 80%). Mild SC demonstrated normal/supra-normal LVEF, normal VTI and SVR. Moderate SC showed lower LVEF and SVR, yet increased LV end-diastolic volume (LVEDV), VTI, SV and CO compared with mild SC (all p < 0.05). Severe SC was distinguished from moderate SC by markedly reduced LVEF, LVEDV, VTI, SV, CO and significantly increased SVR (all p < 0.05). LVEF and VTI decreased over time in mild SC, LVEF decreased in moderate SC, and LVEF and VTI increased over time in severe SC (p ≤ 0.038). LVEF and VTI demonstrated significant performance in identifying severe SC [cut-off < 61.5%, area under the curve (AUC) = 1 ± 0.0, sensitivity/specificity = 100/100, p < 0.001 vs. cut-off < 17.9 cm, AUC = 0.882 ± 0.042, sensitivity/specificity = 80/77, p < 0.001, respectively]. VTI but not LVEF demonstrated significant diagnostic performance in identifying both SVR < 800 dynes·s·cm−5 and SVR > 1500 dynes·s·cm−5 (cut-off > 24.46 cm, AUC = 0.889 ± 0.049, sensitivity/specificity = 75/100, p < 0.001; cut-off < 16.8, AUC = 0.0.857 ± 0.082, sensitivity/specificity = 83/86, p = 0.002, respectively).Conclusions: our study suggests that ICU bedside echocardiographic assessment of LVEF, VTI and their adjusted to corresponding SVR values provides valuable insights for the comprehension of SC phenotypes, underlying vasoplegia and cardiac output fluctuations in septic shock.

High-Dose Hydroxocobalamin for Refractory Vasoplegia Post Cardiac Surgery

Administration of high-dose hydroxocobalamin, or vitamin B12, is an emerging, targeted rescue therapy for the treatment of refractory vasoplegic shock. This is an uncommon but potentially life-threatening complication following cardiac surgery and carries a poor prognosis, particularly when patients fail to respond to first-line therapy with catecholamine vasopressors. This study describes our experience in treating refractory vasodilatory shock following cardiac surgery with high-dose hydroxocobalamin. Administration of hydroxocobalamin in seven patients was associated with an improvement in mean arterial blood pressure or reduction in vasopressor requirements, which were both immediate and sustained throughout our observational period. No deaths or adverse effects attributable to hydroxocobalamin administration occurred in our cohort. Our observations show that high-dose hydroxocobalamin is a safe and effective rescue therapy in refractory vasoplegic shock post cardiopulmonary bypass (CPB).

Luteolin alleviates vascular dysfunctions in CLP-induced polymicrobial sepsis in mice

BACKGROUND

Luteolin, a naturally occurring flavonoid, is thought to have health-promoting properties as a part of human diet and has been reported to possess a wide range of pharmacological activities. Therefore, the present study was undertaken to evaluate the effect of luteolin pre-treatment on vascular dysfunctions in sepsis induced by caecal ligation and puncture (CLP) in the mouse model.

METHODS

Mice were divided into four groups: sham, luteolin plus sham, CLP, and luteolin plus CLP. Luteolin was administered (0.2 mg/kg body weight) intraperitoneally one hour (h) before CLP surgery in mice. 20 ± 2 h post CLP surgery, the isolated thoracic aorta of mice was assessed for its vascular reactivity to noradrenaline (NA) and acetylcholine (ACh). To explore the underlying mechanism, aortic mRNA expressions of α_1D adrenoceptors, eNOS and iNOS were investigated.

RESULTS

In mice with CLP-induced sepsis luteolin pre-treatment markedly increased the survival time and attenuated serum lactate level. The CLP group manifested the reduced vascular reactivity to NA and this deficit was restored by luteolin pre-treatment. However, luteolin pre-treatment did not improve α_1D adrenoceptors down-regulation observed in septic mice aorta. In the presence of 1400 W, the NA contractile response was significantly restored in CLP mice aortic tissue in comparison with the respective control of septic mice and further enhanced in the presence of luteolin. Luteolin reduced the iNOS mRNA expression and iNOS-derived nitrite production. Pre-treatment with luteolin restored the endothelial dysfunction in septic mice aorta by improving eNOS mRNA expression and enhanced eNOS-derived nitric oxide (NO) production in septic mice aorta and aortic iNOS gene expression and inducible NO production.

CONCLUSION

The present study suggests that the vasoplegic state to NA in aorta was restored through the iNOS pathway and endothelial dysfunction was reversed via eNOS and NO production pathway.

A Nutraceutical Product Based on a Mixture of Algae and Extra Virgin Olive Oils and Olive Leaf Extract Attenuates Sepsis-Induced Cardiovascular and Muscle Alterations in Rats

Nutraceuticals are products of natural origin widely used for the treatment and/or prevention of some chronic diseases that are highly prevalent in Western countries, such as obesity or type II diabetes, among others. However, its possible use in the prevention of acute diseases that can put life at risk has been poorly studied. Sepsis is an acute condition that causes cardiovascular and skeletal muscle damage due to a systemic inflammatory state. The aim of this work was to evaluate the possible beneficial effect of a new nutraceutical based on a mixture of algae oil (AO) and extra virgin olive oil (EVOO) supplemented with an olive leaf extract (OLE) in the prevention of cardiovascular alterations and skeletal muscle disorders induced by sepsis in rats. For this purpose, male Wistar rats were treated with the nutraceutical or with water p.o. for 3 weeks and after the treatment they were injected with 1mg/kg LPS twice (12 and 4 h before sacrifice). Pretreatment with the nutraceutical prevented the LPS-induced decrease in cardiac contractility before and after the hearts were subjected to ischemia-reperfusion. At the vascular level, supplementation with the nutraceutical did not prevent hypotension in septic animals, but it attenuated endothelial dysfunction and the increased response of aortic rings to the vasoconstrictors norepinephrine and angiotensin-II induced by LPS. The beneficial effects on cardiovascular function were associated with an increased expression of the antioxidant enzymes SOD-1 and GSR in cardiac tissue and SOD-1 and Alox-5 in arterial tissue. In skeletal muscle, nutraceutical pretreatment prevented LPS-induced muscle proteolysis and autophagy and significantly increased protein synthesis as demonstrated by decreased expression of MURF-1, atrogin-1, LC3b and increased MCH-I and MCH -IIa in gastrocnemius muscle. These effects were associated with a decrease in the expression of TNFα, HDAC4 and myogenin. In conclusion, treatment with a new nutraceutical based on a mixture of AO and EVOO supplemented with OLE is useful to prevent cardiovascular and muscular changes induced by sepsis in rats. Thus, supplementation with this nutraceutical may constitute an interesting strategy to reduce the severity and mortality risk in septic patients.

Characterization of Systemic and Regional Hemodynamics and Vascular Dysfunction in Mice with Fecal Induced Peritonitis

Sepsis is associated with circulatory dysfunction contributing to disturbed blood flow and organ injury. Decreased organ perfusion in sepsis is attributed, in part, to the loss of vasoregulatory mechanisms. Identifying which vascular beds are most susceptible to dysfunction is important for monitoring the recovery of organ function and guiding interventions. This study aimed to investigate the development of vascular dysfunction as sepsis progressed to septic shock. Anesthetized C57Bl/6 mice were instrumented with a fiberoptic pressure sensor in the carotid artery for blood pressure measurements. In subgroups of mice, regional blood flow measurements were taken by positioning a perivascular flow probe around either the left carotid, left renal, or superior mesenteric arteries. Hemodynamic parameters and their responsiveness to bolus doses of vasoactive drugs were recorded prior to and continuously after injection of fecal slurry (1.3 mg/g body weight) for 4 h. Fecal slurry-induced peritonitis reduced mean arterial pressure (62.7 ± 2.4 mmHg vs. 37.5 ± 3.2 mmHg in vehicle and septic mice, respectively), impaired cardiac function, and eventually reduced organ blood flow (71.9%, 66.8%, and 65.1% in the superior mesenteric, renal, and carotid arteries, respectively). The mesenteric vasculature exhibited dysregulation before the renal and carotid arteries, and this underlying dysfunction preceded the blood pressure decline and impaired organ blood flow.

Outcome of Atrial Fibrillation in Patients With Sepsis

Background

Atrial fibrillation (AF) is one of the most frequent arrhythmias in critically ill patients. Sepsis is a major cause of inpatient mortality and it has been associated with cardiac arrhythmias. The objective of this study was to study the outcome of atrial fibrillation in patients who are admitted with sepsis.

Methods

This is a prospective, single-center cohort study of patients admitted to the Medicine Department between June 1, 2019, and November 30, 2019. The inclusion criteria were adult patients with sepsis and septic shock. In this study, 113 patients were enrolled and outcomes were compared between the group that developed atrial fibrillation during the hospital stay and the group without atrial fibrillation.

Results

There were 57 (50.4%) patients with AF including 23 (20.4%) who also had a prior history. Total inpatient mortality was 42 (37.2%), of which 17 patients (40.5%) had AF. AF was not found to be associated with higher mortality or increased length of hospital stay (p-value 0.103 and 0.858, respectively).

Conclusion

AF was not found to be a cause of higher mortality in patients with sepsis or septic shock. There is a need for larger-scale studies to find out the causes of high inpatient mortality in sepsis and the need for local guidelines regarding the management of AF in critically ill patients.

Can the cytokine adsorber CytoSorb® help to mitigate cytokine storm and reduce mortality in critically ill patients? A propensity score matching analysis

Background

A cytokine storm is life threatening for critically ill patients and is mainly caused by sepsis or severe trauma. In combination with supportive therapy, the cytokine adsorber Cytosorb^® (CS) is increasingly used for the treatment of cytokine storm. However, it is questionable whether its use is actually beneficial in these patients.

Methods

Patients with an interleukin-6 (IL-6) > 10,000 pg/ml were retrospectively included between October 2014 and May 2020 and were divided into two groups (group 1: CS therapy; group 2: no CS therapy). Inclusion criteria were a regularly measured IL-6 and, for patients allocated to group 1, CS therapy for at least 90 min. A propensity score (PS) matching analysis with significant baseline differences as predictors (Simplified Acute Physiology Score (SAPS) II, extracorporeal membrane oxygenation, renal replacement therapy, IL-6, lactate and norepinephrine demand) was performed to compare both groups (adjustment tolerance: < 0.05; standardization tolerance: < 10%). U-test and Fisher’s-test were used for independent variables and the Wilcoxon test was used for dependent variables.

Results

In total, 143 patients were included in the initial evaluation (group 1: 38; group 2: 105). Nineteen comparable pairings could be formed (mean initial IL-6: 58,385 vs. 59,812 pg/ml; mean SAPS II: 77 vs. 75). There was a significant reduction in IL-6 in patients with (p < 0.001) and without CS treatment (p = 0.005). However, there was no significant difference (p = 0.708) in the median relative reduction in both groups (89% vs. 80%). Furthermore, there was no significant difference in the relative change in C-reactive protein, lactate, or norepinephrine demand in either group and the in-hospital mortality was similar between groups (73.7%).

Conclusion

Our study showed no difference in IL-6 reduction, hemodynamic stabilization, or mortality in patients with Cytosorb^® treatment compared to a matched patient population.

Hemodynamic Impact of Cardiovascular Antihypertensive Medications in Patients With Sepsis-Related Acute Circulatory Failure

BACKGROUND

Impact of prior cardiovascular antihypertensive medication during the initial phase of septic shock in terms of catecholamine requirements and mortality has been poorly investigated and remains unclear.

OBJECTIVES

To investigate the association between chronic prescription of cardiovascular antihypertensive medication prior to intensive care unit (ICU) admission, catecholamine requirement, and mortality in patients with septic shock.

METHODS

We included all consecutive patients diagnosed with septic shock within the first 24 h of ICU admission, defined as a microbiologically proven or clinically suspected infection, associated with acute circulatory failure requiring vasopressors despite adequate fluid filling. Prior cardiovascular antihypertensive medication was defined as the chronic use of betablockers (BB), calcium channel blockers (CCB), angiotensin converting enzyme inhibitor (ACEi)/angiotensin receptor blockers (ARB). ICU mortality was investigated using multivariate competitive risk analysis.

RESULTS

Among 735 patients admitted for septic shock between 2008 and 2016, 46.9% received prior cardiovascular antihypertensive medication. Prior cardiovascular antihypertensive therapy was not associated with increased norepinephrine requirements during the first 24 h (median = 0.28 μg/kg/min in patients previously treated vs. 0.26 μg/kg/min). Prior cardiovascular antihypertensive medication was not associated with a higher risk of ICU mortality after adjustment (cause-specific hazard = 1.28, 95% confidence interval [0.98-1.66], P = 0.06). Subgroups analyses for BB, CCB, and ACEi/ARB using propensity score analyses retrieved similar results.

CONCLUSION

In patients admitted with septic shock, prior cardiovascular antihypertensive medication seems to have limited impact on initial hemodynamic failure and catecholamine requirement.

Involvement of Toll-Like Receptor 4 in Decreased Vasopressor Response Following Trauma/Hemorrhagic Shock

OBJECTIVES:

Refractory vascular failure due to the inability of vascular smooth muscle to respond to vasoconstrictors such as phenylephrine is a final common pathway for severe circulatory shock of any cause, including trauma/hemorrhagic shock. Increased inflammation, Toll-like receptor 4 activation, and decreased response of the alpha-1 adrenergic receptors which control vascular tone have been reported in trauma/hemorrhagic shock.

HYPOTHESIS:

In trauma/hemorrhagic shock, Toll-like receptor 4 activation contributes to vascular failure via decreased bioavailability of adrenergic receptors.

DESIGN AND MEASUREMENTS:

Trauma/hemorrhagic shock was induced in Wistar rats (laparotomy combined with mean arterial pressure at 40 mm Hg for 90 min followed by 2 hr resuscitation with Lactated Ringers solution). To inhibit Toll-like receptor 4, resatorvid (TAK-242) and resveratrol were used, and plasma was collected. Smooth muscle cells were incubated with lipopolysaccharide (10 ng/mL) or plasma. Inflammatory cytokines were screened using dot-blot. Toll-like receptor 4 and nuclear factor κB activation and cellular localization of the alpha-1 adrenergic receptor were measured by immunofluorescence imaging and Western blot analysis. Clustered regularly interspaced short palindromic repeats/Cas9 was used to knock out Toll-like receptor 4, and calcium influx following stimulation with phenylephrine was recorded.

MAIN RESULTS:

Trauma/hemorrhagic shock caused a decreased response to phenylephrine, whereas Toll-like receptor 4 inhibition improved blood pressure. Trauma/hemorrhagic shock plasma activated the Toll-like receptor 4/nuclear factor κB pathway in smooth muscle cells. Double labeling of Toll-like receptor 4 and the alpha-1 adrenergic receptor showed that these receptors are colocalized on the cell membrane. Activation of Toll-like receptor 4 caused cointernalization of both receptors. Calcium influx was impaired in cells incubated with trauma/hemorrhagic shock plasma but restored when Toll-like receptor 4 was knocked out or inhibited.

CONCLUSIONS:

Activation of the Toll-like receptor 4 desensitizes vascular smooth muscle cells to vasopressors in experimental trauma/hemorrhagic shock by reducing the levels of membrane alpha-1 adrenergic receptor.

Early Positive Fluid Balance is Associated with Mortality in Patients Treated with Veno-Arterial Extra Corporeal Membrane Oxygenation For Cardiogenic Shock: a Retrospective Cohort Study

PURPOSE

Veno-arterial Extracoporeal Membrane Oxygenation (VA-ECMO) provides circulatory assistance for patients in cardiogenic shock. Large quantities of fluids are often required, especially during the early stages, but can result in a potentially harmful fluid-overload. The objective was to determine the association of early fluid-balance and mortality.

METHODS

Retrospective single-center study in 101 VA-ECMO patients between 2013 and 2016. Daily fluid-balance and weight changes over the 5 first days were observed. Analyses between survivors and non-survivors were conducted using Mann-Whitney tests and logistic regression multivariable and Cox hazard-proportional analyses to determine any association with 28-days mortality.

RESULTS

Mortality was 47.5%. The fluid-balance was higher in non-survivors at day-1 (47.3[18.1-71.9] vs. 19.3[1.5-36.2] mL/kg, P < 0.0001) and day-2 (30.6[14.8-71.0] vs. 10.1[-9.8 to 34.7] mL/kg, P = 0.025), as was the cumulative fluid-balance over the first 5 days (107.3[40.5-146.2] vs. 53.0[7.5-74.3] mL/kg, P = 0.04). The administration of unintentional fluids (used for preparation and infusion of drugs) represented an important part of the administrated fluids (15 mL/kg/d-23 mL/kg/d). A significant but moderate correlation was observed between fluid-balance and weight variations over the 5 days (r values ranging from 0.36 to 0.54). Among other parameters, day-1 fluid-balance was independently associated with mortality (OR = 14.34 [1.58-129.79], P = 0.02) and day-1 and day-2 with time to death (HR = 8.26 [1.12-60.98], P = 0.04 and 2.89 [1.26-6.65], P = 0.01). A threshold of 38.8 mL/kg predicted mortality with a sensitivity of 60% and specificity of 83% (area under the curve: 0.749).

CONCLUSION

Early positive fluid-balance is associated with mortality in VA-ECMO patients.

Hemodynamic impact of molecular adsorbent recirculating system in refractory vasoplegic shock due to calcium channel blocker poisoning

OBJECTIVE

To report the hemodynamic effect of to the molecular adsorbent recirculating system (MARS™) therapy for patients in refractory vasoplegic shock due to calcium channel blocker (CCB) poisoning.

METHODS

We report a retrospective cohort of patients who were hospitalized for CCB poisoning with refractory vasoplegic shock and treated by MARS therapy, at Amiens Hospital University, from January 2010 to December 2019. Improvement in hemodynamic was assessed by dynamic changes in mean arterial pressure (MAP) and norepinephrine levels over a 24-h period after MARS therapy. Cardiac function was assessed by transthoracic echocardiography.

RESULTS

MARS therapy was performed on seven patients for CCB poisoning. CCB poisoning included nicardipine (n = 3, 43%) amlodipine (n = 3, 43%), and verapamil (n = 1, 14%). The median time to start MARS therapy was 24 [14-27] h after drug ingestion and 6 [2-9] h after ICU admission. Cardiac output was preserved for all patients. MAP values improved from 56 [43-58] to 65 [61-78] 16 mmHg (p = 0.005). Norepinephrine dose significantly decreased from 3.2 [0.8-10] µg/kg/min to 1.2 [0.1-1.9] µg/kg/min (p = 0.008) and lactate level decreased from 3.2 [2.4-3.4] mmol/l^-1 to 1.6 [0.9-2.2] mmol/l^-1 (p = 0.008). The median length of ICU stay was 4 (2-7) days and hospital stay was 4 (4-16) days. No complication related to the MARS therapy were reported. No patient died and all were discharged from the hospital.

CONCLUSION

We reported the largest case-series of MARS therapy for refractory vasoplegic shock due to CCB poisoning. We observed that MARS therapy was associated with an improvement of hemodynamic parameters.

Relative versus absolute RNA quantification: a comparative analysis based on the example of endothelial expression of vasoactive receptors

BACKGROUND

In the present study, two distinct PCR methods were used for the quantification of genetic material and their results were compared: real-time-PCR (qPCR; relative quantification) and droplet digital PCR (ddPCR; absolute quantification). The comparison of the qPCR and the ddPCR was based on a stimulation approach of microvascular endothelial cells in which the effect of a pro-inflammatory milieu on the expression of vasoactive receptors was investigated.

RESULTS

There was consistency in directions of effects for the majority of genes tested. With regard to the indicated dimension of the effects, the overall picture was more differentiated. It was striking that deviations were more pronounced if the measured values were on the extreme edges of the dynamic range of the test procedures.

CONCLUSIONS

To obtain valid and reliable results, dilution series are recommended, which should be carried out initially. In case of ddPCR the number of copies per µl should be adjusted to the low three-digit range. With regard to qPCR it is essential that the stability and reliability of the reference genes used is guaranteed. Here, ddPCR offers the advantage that housekeeping genes are not required. Furthermore, an absolute quantification of the sample can be easily performed by means of ddPCR. Before using ddPCR, however, care should be taken to optimize the experimental conditions. Strict indications for this methodology should also be made with regard to economic and timing factors.

Vasopressin and copeptin release during sepsis and septic shock

Sepsis is defined as a potentially fatal organ dysfunction caused by a dysregulated host response to infection. Despite tremendous progress in the medical sciences, sepsis remains one of the leading causes of morbidity and mortality worldwide. The host response to sepsis and septic shock involves changes in the immune, autonomic, and neuroendocrine systems. Regarding neuroendocrine changes, studies show an increase in plasma vasopressin (AVP) concentrations followed by a decline, which may be correlated with septic shock. AVP is a peptide hormone derived from a larger precursor (preprohormone), along with two peptides, neurophysin II and copeptin. AVP is synthesized in the hypothalamus, stored and released from the neurohypophysis into the bloodstream by a wide range of stimuli. The measurement of AVP has limitations due to its plasma instability and short half-life. Copeptin is a more stable peptide than AVP, and its immunoassay is feasible. The blood concentrations of copeptin mirror those of AVP in many physiological states; paradoxically, during sepsis-related organ dysfunction, an uncoupling between copeptin and AVP blood levels appears to happen. In this review, we focus on clinical and experimental studies that analyzed AVP and copeptin blood concentrations over time in sepsis. The findings suggest that AVP and copeptin behave similarly in the early stages of sepsis; however, we did not find a proportional decrease in copeptin concentrations as seen with AVP during septic shock. Copeptin levels were higher in nonsurvivors than in survivors, suggesting that copeptin may work as a marker of severity or sepsis-related organ dysfunction.

Impact of downstream effects of glucocorticoid receptor dysfunction on organ function in critical illness-associated systemic inflammation

Glucocorticoids (GCs) are stress hormones that regulate developmental and physiological processes and are among the most potent anti-inflammatory drugs to suppress chronic and acute inflammation. GCs act through the glucocorticoid receptor (GR), a ubiquitously expressed ligand-activated transcription factor, which translocates into the nucleus and can act via two different modes, as a GR monomer or as a GR dimer. These two modes of action are not clearly differentiated in practice and may lead to completely different therapeutic outcomes. Detailed aspects of GR mechanisms are often not taken into account when GCs are used in different clinical scenarios. Patients, with critical illness-related corticosteroid insufficiency, treated with natural or synthetic GCs are still missing a clearly defined therapeutic strategy. This review discusses the different modes of GR function and its importance on organ function in vivo.

The Role of Pi, Glutamine and the Essential Amino Acids in Modulating the Metabolism in Diabetes and Cancer

Purpose

Re-examine the current metabolic models.

Methods

Review of literature and gene networks.

Results

Insulin activates Pi uptake, glutamine metabolism to stabilise lipid membranes. Tissue turnover maintains the metabolic health. Current model of intermediary metabolism (IM) suggests glucose is the source of energy, and anaplerotic entry of fatty acids and amino acids into mitochondria increases the oxidative capacity of the TCA cycle to produce the energy (ATP). The reduced cofactors, NADH and FADH2, have different roles in regulating the oxidation of nutrients, membrane potentials and biosynthesis. Trans-hydrogenation of NADH to NADPH activates the biosynthesis. FADH2 sustains the membrane potential during the cell transformations. Glycolytic enzymes assume the non-canonical moonlighting functions, enter the nucleus to remodel the genetic programmes to affect the tissue turnover for efficient use of nutrients. Glycosylation of the CD98 (4F2HC) stabilises the nutrient transporters and regulates the entry of cysteine, glutamine and BCAA into the cells. A reciprocal relationship between the leucine and glutamine entry into cells regulates the cholesterol and fatty acid synthesis and homeostasis in cells. Insulin promotes the Pi transport from the blood to tissues, activates the mitochondrial respiratory activity, and glutamine metabolism, which activates the synthesis of cholesterol and the de novo fatty acids for reorganising and stabilising the lipid membranes for nutrient transport and signal transduction in response to fluctuations in the microenvironmental cues. Fatty acids provide the lipid metabolites, activate the second messengers and protein kinases. Insulin resistance suppresses the lipid raft formation and the mitotic slippage activates the fibrosis and slow death pathways.

Role of resveratrol in protecting vasodilatation function in septic shock rats and its mechanism

BACKGROUND

Vascular dysfunction is a major cause of sepsis-induced multiple-organ dysfunction. Resveratrol is a polyphenol compound with extensive pharmacological effects including anti-inflammation. The aim of this study was to determine the role and mechanism of resveratrol in protecting vascular function following sepsis.

METHODS

The cecal ligation and puncture method was used to establish a septic shock rat model. Resveratrol (5 mg/kg and 10 mg/kg) was administered intravenously immediately and at 12 hours after cecal ligation and puncture, respectively. The effects of resveratrol on vasodilatation function, blood flow velocity, hemodynamics, and vital organ function and its relationship to Rac-1 and HIF-1α were observed.

RESULTS

Vascular relaxation reactivity and blood flow velocity were significantly decreased after septic shock, both were significantly improved by resveratrol 5 mg/kg and 10 mg/kg, and the effect of 10 mg/kg was greater. The relaxation reactivity of the superior mesenteric artery to acetylcholine (Ach) was increased by 43.2%. The blood flow velocity of mesenteric arterioles and venules was increased by 47.1% and 51%, respectively, after resveratrol (10 mg/kg) administration compared with the septic shock group. The hemodynamics and both liver and kidney blood flow were significantly decreased after septic shock, which were significantly improved them by resveratrol, which enhanced the vascular relaxation reactivity in septic shock rats. The 72-hour survival rate of septic shock rats in the resveratrol group (62.5%) was significantly higher than that in the septic shock group (6.3%). Resveratrol significantly upregulated the expression of endothelial nitric oxide synthase (eNOS) and downregulated the expression of inducible NOS, Rac-1, and HIF-1α. Inhibitors of Rac-1 and HIF-1α significantly improved the expression of eNOS, and inhibition of eNOS (L-NAME, 5 mg/kg) antagonized the resveratrol-induced improvement in vascular relaxation reactivity and survival.

CONCLUSION

Resveratrol was beneficial for vasodilatation function in rats with septic shock, which is the major contribution to resveratrol improving hemodynamics and organ perfusion. The mechanism involved resveratrol upregulating the expression of eNOS by inhibiting Rac-1 and HIF-1α.

Molecular mechanisms by which iNOS uncoupling can induce cardiovascular dysfunction during sepsis: Role of posttranslational modifications (PTMs)

Human sepsis is the result of a multifaceted pathological process causing marked dysregulation of cardiovascular responses. A more sophisticated understanding of the pathogenesis of sepsis is certainly prerequisite. Evidence from studies provide further insight into the role of inducible nitric oxide synthase (iNOS) isoform. Results on inhibition of iNOS in sepsis models remain inconclusive. Concern has been devoted to improving our knowledge and understanding of the role of iNOS. The aim of this review is to define the role of iNOS in redox homeostasis disturbance, the detailed mechanisms linking iNOS and posttranslational modifications (PTMs) to cardiovascular dysfunctions, and their future implications in sepsis settings. Many questions related to the iNOS and PTMs still remain open, and much more work is needed on this.

Organ Dysfunction in Sepsis: An Ominous Trajectory From Infection To Death

Sepsis is a highly complex and lethal syndrome with highly heterogeneous clinical manifestations that makes it difficult to detect and treat. It is also one of the major and most urgent global public health challenges. More than 30 million people are diagnosed with sepsis each year, with 5 million attributable deaths and long-term sequalae among survivors. The current international consensus defines sepsis as a life-threatening organ dysfunction caused by a dysregulated host response to an infection. Over the past decades substantial research has increased the understanding of its pathophysiology. The immune response induces a severe macro and microcirculatory dysfunction that leads to a profound global hypoperfusion, injuring multiple organs. Consequently, patients with sepsis might present dysfunction of virtually any system, regardless of the site of infection. The organs more frequently affected are kidneys, liver, lungs, heart, central nervous system, and hematologic system. This multiple organ failure is the hallmark of sepsis and determines patients' course from infection to recovery or death. There are tools to assess the severity of the disease that can also help to guide treatment, like the Sequential Organ Failure Assessment (SOFA) score. However, sepsis disease process is vastly heterogeneous, which could explain why interventions targeted to directly intervene its mechanisms have shown unsuccessful results and predicting outcomes with accuracy is still elusive. Thus, it is required to implement strong public health strategies and leverage novel technologies in research to improve outcomes and mitigate the burden of sepsis and septic shock worldwide.

Lipopolysaccharide exposure modulates the contractile and migratory phenotypes of vascular smooth muscle cells

INTRODUCTION

Sepsis survivors are at higher risk for cardiovascular events. Lipopolysaccharide (LPS) activates Toll-like receptor 4 (TLR4) in sepsis. Activation of TLR4 modulates vascular smooth muscle cells (VSMCs) phenotype and contributes to cardiovascular changes after sepsis.

AIM

Investigate changes in VSMCs phenotype caused by LPS-induced TLR4 activation.

METHODS

Rat VSMCs were incubated with LPS. Two incubation conditions were used in cell contraction and migration assays: acute stimulation - LPS stimulus was initiated at the beginning of the assay and maintained throughout; and preconditioning - LPS stimulation was applied prior to the assay then discontinued. Nitric oxide (NO) production, mRNA expression of cytokines and phenotype markers, and interleukin (IL)-6 production were evaluated.

KEY FINDINGS

LPS increased gene expression of IL-1β, IL-6, TNFα and MCP-1 (p < .001), of secretory phenotype markers collagen and vimentin (p < .0479) and of the contractile marker smooth muscle 22α (SM22α) (p = .0067). LPS exposure increased IL-6 secretion after 24 and 48 h (p < .0001), and NO at 8 and 24 h (p < .0249) via inducible nitric oxide synthase (iNOS), as demonstrated by a decrease in NO after incubation with aminoguanidine. Acute stimulation with LPS reduced migration and contraction in a NO-dependent manner, while preconditioning with LPS increased both in an IL-6-dependent manner.

SIGNIFICANCE

LPS affects VSMCs by modulating their secretory, contractile and migratory phenotypes. LPS acute stimulation of VSMCs promoted a NO-dependent reduction in migration and contraction, while preconditioning with LPS promoted IL-6-dependent increases in migration and contraction, evidencing that VSMCs can present phenotype modifications that persist after sepsis, thereby contributing to postsepsis cardiovascular events.

Role of Nitric Oxide Carried by Hemoglobin in Cardiovascular Physiology: Developments on a Three-Gas Respiratory Cycle

A continuous supply of oxygen is essential for the survival of multicellular organisms. The understanding of how this supply is regulated in the microvasculature has evolved from viewing erythrocytes (red blood cells [RBCs]) as passive carriers of oxygen to recognizing the complex interplay between Hb (hemoglobin) and oxygen, carbon dioxide, and nitric oxide-the three-gas respiratory cycle-that insures adequate oxygen and nutrient delivery to meet local metabolic demand. In this context, it is blood flow and not blood oxygen content that is the main driver of tissue oxygenation by RBCs. Herein, we review the lines of experimentation that led to this understanding of RBC function; from the foundational understanding of allosteric regulation of oxygen binding in Hb in the stereochemical model of Perutz, to blood flow autoregulation (hypoxic vasodilation governing oxygen delivery) observed by Guyton, to current understanding that centers on S-nitrosylation of Hb (ie, S-nitrosohemoglobin; SNO-Hb) as a purveyor of oxygen-dependent vasodilatory activity. Notably, hypoxic vasodilation is recapitulated by native S-nitrosothiol (SNO)-replete RBCs and by SNO-Hb itself, whereby SNO is released from Hb and RBCs during deoxygenation, in proportion to the degree of Hb deoxygenation, to regulate vessels directly. In addition, we discuss how dysregulation of this system through genetic mutation in Hb or through disease is a common factor in oxygenation pathologies resulting from microcirculatory impairment, including sickle cell disease, ischemic heart disease, and heart failure. We then conclude by identifying potential therapeutic interventions to correct deficits in RBC-mediated vasodilation to improve oxygen delivery-steps toward effective microvasculature-targeted therapies. To the extent that diseases of the heart, lungs, and blood are associated with impaired tissue oxygenation, the development of new therapies based on the three-gas respiratory system have the potential to improve the well-being of millions of patients.

Toward the Existence of a Sympathetic Neuroplasticity Adaptive Mechanism Influencing the Immune Response. A Hypothetical View-Part II

In the preceding work, a hypothesis on the existence of a specific neural plasticity program from sympathetic fibers innervating secondary lymphoid organs was introduced. This proposed adaptive mechanism would involve segmental retraction and degeneration of noradrenergic terminals during the immune system (IS) activation followed by regeneration once the IS returns to the steady-state. Starting from such view, this second part presents clinical and experimental evidence allowing to envision that this sympathetic neural plasticity mechanism is also operative on inflamed non-lymphoid peripheral tissues. Importantly, the sympathetic nervous system regulates most of the physiological bodily functions, ranging from cardiovascular, respiratory and gastro-intestinal functions to endocrine and metabolic ones, among others. Thus, it seems sensible to think that compensatory programs should be put into place during inflammation in non-lymphoid tissues as well, to avoid the possible detrimental consequences of a sympathetic blockade. Nevertheless, in many pathological scenarios like severe sepsis, chronic inflammatory diseases, or maladaptive immune responses, such compensatory programs against noradrenergic transmission impairment would fail to develop. This would lead to a manifest sympathetic dysfunction in the above-mentioned settings, partly accounting for their underlying pathophysiological basis; which is also discussed. The physiological/teleological significance for the whole neural plasticity process is postulated, as well.

Peroxynitrite decomposition catalyst reduces vasopressin requirement in ovine MRSA sepsis

Background

Sepsis is one of the most frequent causes of death in the intensive care unit. Host vascular hypo-responsiveness to vasopressors during septic shock is one of the challenging problems. This study tested the hypothesis that adjunct therapy with peroxynitrite decomposition catalyst (WW-85) would reduce arginine vasopressin (AVP) requirements during sepsis resuscitation, using ovine sepsis model.

Methods

Thirteen adult female Merino sheep, previously instrumented with multiple vascular catheters, were subjected to “two-hit” (cotton smoke inhalation and intrapulmonary instillation of live methicillin-resistant Staphylococcus aureus; 3.5 × 10¹¹ colony-forming units) injury. Post injury, animals were awakened and randomly allocated to the following groups: (1) AVP: injured, fluid resuscitated, and titrated with AVP, n = 6 or (2) WW-85 + AVP: injured, fluid resuscitated, treated with WW-85, and titrated with AVP, n = 7. One-hour post injury, a bolus intravenous injection of WW-85 (0.1 mg/kg) was followed by a 23-h continuous infusion (0.02 mg/kg/h). Titration of AVP started at a dose of 0.01 unit/min, when mean arterial pressure (MAP) decreased by 10 mmHg from baseline, despite aggressive fluid resuscitation, and the rate was further adjusted to maintain MAP. After the injury, all animals were placed on a mechanical ventilator and monitored in the conscious state for 24 h.

Results

The injury induced severe hypotension refractory to aggressive fluid resuscitation. High doses of AVP were required to partially attenuate the sepsis-induced hypotension. However, the cumulative AVP requirement was significantly reduced by adjunct treatment with WW-85 at 17–24 h after the injury (p < 0.05). Total AVP dose and the highest AVP rate were significantly lower in the WW-85 + AVP group compared to the AVP group (p = 0.02 and 0.04, respectively). Treatment with WW-85 had no adverse effects. In addition, the in vitro effects of AVP on isolated artery diameter changes were abolished with peroxynitrite co-incubation.

Conclusions

The modulation of reactive nitrogen species, such as peroxynitrite, may be considered as a novel adjunct treatment option for septic shock associated with vascular hypo-responsiveness to vasopressors.

Comparison of International Pediatric Sepsis Consensus Conference Versus Sepsis-3 Definitions for Children Presenting With Septic Shock to a Tertiary Care Center in India: A Retrospective Study

OBJECTIVES

To evaluate the proportion of children fulfilling "Sepsis-3" definition and International Pediatric Sepsis Consensus Conference definition among children diagnosed to have septic shock and compare the mortality risk between the two groups.

DESIGN

Retrospective chart review.

SETTING

PICU of a tertiary care teaching hospital from 2014 to 2017.

PATIENTS

Children (≤ 17 yr old) with a diagnosis of septic shock at admission or during PICU stay.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We applied both International Pediatric Sepsis Consensus Conference and the new "Sepsis-3" definition (sepsis with hypotension requiring vasopressors and a lactate value of ≥ 2 mmol/L) to identify cases of septic shock by these definitions. Key outcomes such as mortality, proportion attaining shock reversal at 24 hours and organ dysfunction were compared between those fulfilling "Sepsis-3" definitions ("Sepsis-3" group) and those fulfilling "International Pediatric Sepsis Consensus Conference" definition ("International Pediatric Sepsis Consensus Conference" group). A total of 216 patients fulfilled International Pediatric Sepsis Consensus Conference definitions of septic shock. Of these, only 104 (48%; 95% CI, 42-55) fulfilled "Sepsis-3" definition. Children fulfilling "Sepsis-3 plus International Pediatric Sepsis Consensus Conference definitions" ("Sepsis-3 and International Pediatric Sepsis Consensus Conference" group) had lower proportion with shock resolution (61% vs 82%; relative risk, 0.73; 95% CI, 0.62-0.88) and higher risk of multiple organ dysfunction (85% vs 68%; 1.24; 1.07-1.45) at 24 hours. The mortality was 48.5% in "Sepsis-3 and International Pediatric Sepsis Consensus Conference" group as compared with 37.5% in the "International Pediatric Sepsis Consensus Conference only" group (relative risk, 1.3; 95% CI, 0.94-1.75).

CONCLUSIONS

Less than half of children with septic shock identified by International Pediatric Sepsis Consensus Conference definitions were observed to fulfill the criteria for shock as per "Sepsis-3" definitions. Lack of difference in the risk of mortality between children who fulfilled "Sepsis-3" definition and those who did not fulfill the definition raises questions on the appropriateness of using this definition for diagnosis of septic shock in children.