A Lifelike guided journey through the pathophysiology of pulmonary hypertension-from measured metabolites to the mechanism of action of drugs.

Introduction: Pulmonary hypertension (PH) is a pathological condition that affects approximately 1% of the population. The prognosis for many patients is poor, even after treatment. Our knowledge about the pathophysiological mechanisms that cause or are involved in the progression of PH is incomplete. Additionally, the mechanism of action of many drugs used to treat pulmonary hypertension, including sotatercept, requires elucidation. Methods: Using our graph-powered knowledge mining software Lifelike in combination with a very small patient metabolite data set, we demonstrate how we derive detailed mechanistic hypotheses on the mechanisms of PH pathophysiology and clinical drugs. Results: In PH patients, the concentration of hypoxanthine, 12(S)-HETE, glutamic acid, and sphingosine 1 phosphate is significantly higher, while the concentration of L-arginine and L-histidine is lower than in healthy controls. Using the graph-based data analysis, gene ontology, and semantic association capabilities of Lifelike, led us to connect the differentially expressed metabolites with G-protein signaling and SRC. Then, we associated SRC with IL6 signaling. Subsequently, we found associations that connect SRC, and IL6 to activin and BMP signaling. Lastly, we analyzed the mechanisms of action of several existing and novel pharmacological treatments for PH. Lifelike elucidated the interplay between G-protein, IL6, activin, and BMP signaling. Those pathways regulate hallmark pathophysiological processes of PH, including vasoconstriction, endothelial barrier function, cell proliferation, and apoptosis. Discussion: The results highlight the importance of SRC, ERK1, AKT, and MLC activity in PH. The molecular pathways affected by existing and novel treatments for PH also converge on these molecules. Importantly, sotatercept affects SRC, ERK1, AKT, and MLC simultaneously. The present study shows the power of mining knowledge graphs using Lifelike's diverse set of data analytics functionalities for developing knowledge-driven hypotheses on PH pathophysiological and drug mechanisms and their interactions. We believe that Lifelike and our presented approach will be valuable for future mechanistic studies of PH, other diseases, and drugs.

The Effect of Targeted Temperature Management on the Metabolome Following Out-of-Hospital Cardiac Arrest.

Targeted temperature management (TTM) may moderate the injury from out-of-hospital cardiac arrest. Slowing the metabolism has been a suggested effect. Nevertheless, studies have found higher lactate levels in patients cooled to 33°C compared with 36°C even days from TTM cessation. Larger studies have not been performed on the TTM's effect on the metabolome. Accordingly, to explore the effect of TTM, we used ultra-performance liquid-mass spectrometry in a substudy of 146 patients randomized in the TTM trial to either 33°C or 36°C for 24 hours and quantified 60 circulating metabolites at the time of hospital arrival (T0) and 48 hours later (T48). From T0 to T48, profound changes to the metabolome were observed: tricarboxylic acid (TCA) cycle metabolites, amino acids, uric acid, and carnitine species all decreased. TTM significantly modified these changes in nine metabolites (Benjamini-Hochberg corrected false discovery rate <0.05): branched amino acids valine and leucine levels dropped more in the 33°C arm (change [95% confidence interval]: -60.9 µM [-70.8 to -50.9] vs. -36.0 µM [-45.8 to -26.3] and -35.5 µM [-43.1 to -27.8] vs. -21.2 µM [-28.7 to -13.6], respectively), whereas the TCA metabolites including malic acid and 2-oxoglutaric acid remained higher for the first 48 hours (-7.7 µM [-9.7 to -5.7] vs. -10.4 µM [-12.4 to -8.4] and -3 µM [-4.3 to -1.7] vs. -3.7 µM [-5 to -2.3]). Prostaglandin E2 only dropped in the TTM 36°C group. The results show that TTM affects the metabolism hours after normothermia have been reached. Clinical Trial Number: NCT01020916.

Major open abdominal surgery is associated with increased levels of endothelial damage and interleukin-6.

OBJECTIVE: To examine changes in biomarkers of endothelial glycocalyx shedding, endothelial damage, and surgical stress following major open abdominal surgery and the correlation to postoperative morbidity. INTRODUCTION: Major abdominal surgery is associated with high levels of postoperative morbidity. Two possible reasons are the surgical stress response and the impairment of the glycocalyx and endothelial cells. Further, the degree of these responses may correlate with postoperative morbidity and complications. METHODS: A secondary data analysis of prospectively collected data from two cohorts of patients undergoing open liver surgery, gastrectomy, esophagectomy, or Whipple procedure (n = 112). Hemodynamics and blood samples were collected at predefined timestamps and analyzed for biomarkers of glycocalyx shedding (Syndecan-1), endothelial activation (sVEGFR1), endothelial damage (sThrombomodulin (sTM)), and surgical stress (IL6). RESULTS: Major abdominal surgery led to increased levels of IL6 (0 to 85 pg/mL), Syndecan-1 (17.2 to 46.4 ng/mL), and sVEGFR1 (382.8 to 526.5 pg/mL), peaking at the end of the surgery. In contrast, sTM, did not increase during surgery, but increased significantly following surgery (5.9 to 6.9 ng/mL), peaking at 18 h following the end of surgery. Patients characterized with high postoperative morbidity had higher levels of IL6 (132 vs. 78 pg/mL, p = 0.007) and sVEGFR1 (563.1 vs. 509.4 pg/mL, p = 0.045) at the end of the surgery, and of sTM (8.2 vs. 6.4 ng/mL, p = 0.038) 18 h following surgery. CONCLUSION: Major abdominal surgery leads to significantly increased levels of biomarkers of endothelial glycocalyx shedding, endothelial damage, and surgical stress, with the highest levels seen in patients developing high postoperative morbidity.

Associations of ABO and Rhesus D blood groups with phenome-wide disease incidence: A 41-year retrospective cohort study of 482,914 patients.

Background: Whether natural selection may have attributed to the observed blood group frequency differences between populations remains debatable. The ABO system has been associated with several diseases and recently also with susceptibility to COVID-19 infection. Associative studies of the RhD system and diseases are sparser. A large disease-wide risk analysis may further elucidate the relationship between the ABO/RhD blood groups and disease incidence. Methods: We performed a systematic log-linear quasi-Poisson regression analysis of the ABO/RhD blood groups across 1,312 phecode diagnoses. Unlike prior studies, we determined the incidence rate ratio for each individual ABO blood group relative to all other ABO blood groups as opposed to using blood group O as the reference. Moreover, we used up to 41 years of nationwide Danish follow-up data, and a disease categorization scheme specifically developed for diagnosis-wide analysis. Further, we determined associations between the ABO/RhD blood groups and the age at the first diagnosis. Estimates were adjusted for multiple testing. Results: The retrospective cohort included 482,914 Danish patients (60.4% females). The incidence rate ratios (IRRs) of 101 phecodes were found statistically significant between the ABO blood groups, while the IRRs of 28 phecodes were found statistically significant for the RhD blood group. The associations included cancers and musculoskeletal-, genitourinary-, endocrinal-, infectious-, cardiovascular-, and gastrointestinal diseases. Conclusions: We found associations of disease-wide susceptibility differences between the blood groups of the ABO and RhD systems, including cancer of the tongue, monocytic leukemia, cervical cancer, osteoarthrosis, asthma, and HIV- and hepatitis B infection. We found marginal evidence of associations between the blood groups and the age at first diagnosis. Funding: Novo Nordisk Foundation and the Innovation Fund Denmark.

Estimating the effect of donor sex on red blood cell transfused patient mortality: A retrospective cohort study using a targeted learning and emulated trials-based approach.

Background: Observational studies determining the effect of red blood cell (RBC) donor sex on recipient mortality have been inconsistent. Emulating hypothetical randomized target trials using large real-world data and targeted learning may clarify potential adverse effects. Methods: In this retrospective cohort study, a RBC transfusion database from the Capital Region of Denmark comprising more than 900,000 transfusion events defined the observational data. Eligible patients were minimum 18 years, had received a leukocyte-reduced RBC transfusion, and had no history of RBC transfusions within the past year at baseline. The doubly robust targeted maximum likelihood estimation method coupled with ensembled machine learning was used to emulate sex-stratified target trials determining the comparative effectiveness of exclusively transfusing RBC units from either male or female donors. The outcome was all-cause mortality within 28 days of the baseline-transfusion. Estimates were adjusted for the total number of transfusions received on each day k, hospital of transfusion, calendar period, patient age and sex, ABO/RhD blood group of the patient, Charlson comorbidity score, the total number of transfusions received prior to day k, and the number of RBC units received on each day k from donors younger than 40 years of age. Findings: Among 98,167 adult patients who were transfused between Jan. 1, 2008, and Apr. 10, 2018, a total of 90,917 patients (54.6% female) were eligible. For male patients, the 28-day survival was 2.06 percentage points (pp) (95 % confidence interval [CI]: 1.81-2.32, P<0.0001) higher under treatment with RBC units exclusively from male donors compared with exclusively from female donors. In female patients, exclusively transfusing RBC units from either male or female donors increased the 28-day survival with 0.64pp (0.52-0.76, P<0.0001), and 0.62pp (0.49-0.75, P<0.0001) compared with the current practice, respectively. No evidence of a sex-specific donor effect was found for female patients (0.02pp [-0.18-0.22]). The sensitivity analyses showed that a large unknown causal bias would have to be present to affect the conclusions. Interpretation: The results suggest that a sex-matched transfusion policy may benefit patients. However, a causal interpretation of the findings relies on the assumption of no unmeasured confounding, treatment consistency, positivity, and minimal model misspecifications. Funding: Novo Nordisk Foundation and the Innovation Fund Denmark.

Intervening on the storage time of RBC units and its effects on adverse recipient outcomes using real-world data.

Randomized controlled trials (RCTs) have found no evidence that the storage time of transfused red blood cell (RBC) units affects recipient survival. However, inherent difficulties in conducting RBC transfusion RCTs have prompted critique of their design, analyses, and interpretation. Here, we address these issues by emulating hypothetical randomized trials using large real-world data to further clarify the adverse effects of storage time. We estimated the comparative effect of transfusing exclusively older vs fresher RBC units on the primary outcome of death, and the secondary composite end point of thromboembolic events, or death, using inverse probability weighting. Thresholds were defined as 1, 2, 3, and 4 weeks of storage. A large Danish blood transfusion database from the period 2008 to 2018 comprising >900 000 transfusion events defined the observational data. A total of 89 799 patients receiving >340 000 RBC transfusions during 28 days of follow-up met the eligibility criteria. Treatment with RBC units exclusively fresher than 1, 2, 3, and 4 weeks of storage was found to decrease the 28-day recipient mortality with 2.44 percentage points (pp) (0.86 pp, 4.02 pp), 1.93 pp (0.85 pp, 3.02 pp), 1.06 pp (-0.20 pp, 2.33 pp), and -0.26 pp (-1.78 pp, 1.25 pp) compared with transfusing exclusively older RBC units, respectively. The 28-day risk differences for the composite end point were similar. This study suggests that transfusing exclusively older RBC units stored for >1 or 2 weeks increases the 28-day recipient mortality and risk of thromboembolism or death compared with transfusing fresher RBC units.

Evaluation of the systemic inflammatory response, endothelial cell dysfunction, and postoperative morbidity in patients, receiving perioperative corticosteroid, developing severe mesenteric traction syndrome - an exploratory study.

OBJECTIVE: To determine whether a severe mesenteric traction syndrome (MTS) leads to increased surgical stress, endothelial dysfunction, and postoperative morbidity in a cohort in which all patients received a single dose of methylprednisolone. INTRODUCTION: Preoperatively administered corticosteroids lower the incidence of severe MTS and may also attenuate surgical stress and endothelial damage associated with the development of severe MTS, ultimately lowering the postoperative morbidity. METHODS: This exploratory study analyzed prospectively collected data from 45 patients all receiving 125 mg methylprednisolone. No control group was included. The severity of MTS was graded intraoperatively, and postoperative morbidity was assessed blinded. Blood samples for plasma prostacyclin (PGI2), IL6 and endothelial damage (Syndecan-1, sVEGRF1 and sThrombomodulin) biomarkers were obtained at predefined time points. RESULTS: Patients undergoing either open liver surgery (n = 23) or Whipple's procedure (n = 22) were included. No differences were found in postoperative morbidity between patients developing and not developing severe MTS. Surgery led to significantly increased plasma levels of biomarkers indicative of surgical stress and endothelial damage. Further, patients developing severe MTS had increased levels of PGI2 (p = 0.05) and lower systemic vascular resistance (p < 0.05) 15 min into surgery. However, when comparing the biomarkers of surgical stress, endothelial damage no differences between patients with and without severe MTS were identified. CONCLUSION: This exploratory study found that surgery was associated with a pro-inflammatory response and damage to the endothelium. However, no differences were found between patients developing severe MTS and patients developing moderate/no MTS in biomarkers of surgical stress, endothelial damage, or postoperative morbidity. Corticosteroids may therefore attenuate the endothelial damage in patients developing severe MTS. However, as this was an exploratory study, these findings must be confirmed in future randomized controlled studies.

Metabolic Response in Endothelial Cells to Catecholamine Stimulation Associated with Increased Vascular Permeability.

Disruption to endothelial cell homeostasis results in an extensive variety of human pathologies that are particularly relevant to major trauma. Circulating catecholamines, such as adrenaline and noradrenaline, activate endothelial adrenergic receptors triggering a potent response in endothelial function. The regulation of the endothelial cell metabolism is distinct and profoundly important to endothelium homeostasis. However, a precise catalogue of the metabolic alterations caused by sustained high catecholamine levels that results in endothelial dysfunction is still underexplored. Here, we uncover a set of up to 46 metabolites that exhibit a dose-response relationship to adrenaline-noradrenaline equimolar treatment. The identified metabolites align with the glutathione-ascorbate cycle and the nitric oxide biosynthesis pathway. Certain key metabolites, such as arginine and reduced glutathione, displayed a differential response to treatment in early (4 h) compared to late (24 h) stages of sustained stimulation, indicative of homeostatic metabolic feedback loops. Furthermore, we quantified an increase in the glucose consumption and aerobic respiration in endothelial cells upon catecholamine stimulation. Our results indicate that oxidative stress and nitric oxide metabolic pathways are downstream consequences of endothelial cell stimulation with sustained high levels of catecholamines. A precise understanding of the metabolic response in endothelial cells to pathological levels of catecholamines will facilitate the identification of more efficient clinical interventions in trauma patients.

Endothelial dysfunction and thromboembolism in children, adolescents, and young adults with acute lymphoblastic leukemia.

Endothelial dysfunction has not previously been investigated as a thrombogenic risk factor among patients with acute lymphoblastic leukemia (ALL), known to be at high risk of thromboembolism. We retrospectively explored the association between three circulating biomarkers of endothelial dysfunction (thrombomodulin, syndecan-1, VEGFR-1) measured in prospectively collected blood samples and risk of thromboembolism in 55 cases and 165 time-matched controls, treated according to the NOPHO ALL2008 protocol. In age-, sex-, and risk group-adjusted analysis, increasing levels of thrombomodulin and VEGFR-1 were independently associated with increased odds of developing thromboembolism (OR 1.37 per 1 ng/mL [95% CI 1.20‒1.56, P < 0.0001] and OR 1.21 per 100 pg/mL [95% CI 1.02‒1.21, P = 0.005], respectively). These associations remained significant when including only samples drawn >30 days before thromboembolic diagnosis. Thrombomodulin levels were on average 3.2 ng/mL (95% CI 2.6-8.2 ng/mL) higher in samples with measurable asparaginase activity (P < 0.0001). Among single nucleotide variants located in or neighboring coding genes for the three biomarkers, none were significantly associated with odds of thromboembolism. If results are validated in another cohort, thrombomodulin and VEGFR-1 could serve as predictive biomarkers, identifying patients in need of preemptive antithrombotic prophylaxis.

The wound healing effect of local leukocyte platelet-rich plasma after total hip arthroplasty: A randomized controlled trial.

Rapid wound closure is important after arthroplasty procedures to prevent postoperative complications. Platelets are rich in growth factors and leukocytes contribute to innate immunity. We hypothesized that topical leukocyte platelet-rich plasma (L-PRP) derived from the blood of patients would be beneficial to wound healing. In this randomized controlled trial, patients subjected to elective total hip arthroplasty (THA) were assigned by concealed allocation either L-PRP application onto the sutured fascia or no application (control) after the THA intervention. In addition, all patients received 1.5 g protein/kg, 5 g L-arginine, 500 mg vitamin C and 44 mg zinc daily over the 4-week postoperative period to obtain optimal nutrition. The primary endpoint was complete healing of the skin incision. The secondary endpoints were blood transfusions, length of hospital stay, pain and wound infections. Sixteen patients in the L-PRP group and 17 patients in the control group completed the trial. L-PRP treatment accelerated complete wound healing after 3 weeks (seven in the L-PRP group vs. zero in the control group, p = 0.003) and after 4 weeks (12 in the L-PRP group vs. six in the control group, p = 0.037). No postoperative superficial wound infections occurred within 4 weeks, and there were no significant differences in the other secondary outcomes. L-PRP generated in 10 sex-matched healthy volunteers revealed increased concentrations of platelets (5.8-fold) and leukocytes (2.3-fold) compared with those in whole blood. Furthermore, the concentration of keratinocyte mitogen epidermal growth factor in L-PRP (380 ± 130 pg/ml, mean ± SD) was higher (p < 0.001) than that in serum (130 ± 26 pg/ml). In conclusion, a single intraoperative local application of L-PRP promoted wound healing after THA, possibly mediated by EGF receptor agonists.

Severe mesenteric traction syndrome is associated with increased systemic inflammatory response, endothelial dysfunction, and major postoperative morbidity.

This study aimed to determine if mesenteric traction syndrome (MTS) triggers increased systemic inflammation and endothelial cell dysfunction. Patients developing severe MTS had pronounced early IL6 elevations followed by endothelial cell damage. Furthermore, these processes were associated with increased postoperative morbidity. OBJECTIVE: To determine whether mesenteric traction syndrome (MTS) leads to increased systemic inflammation and dysfunction of the glycocalyx and endothelial cell and whether this correlates with the degree of postoperative morbidity. INTRODUCTION: Severe MTS is associated with increased postoperative morbidity following major gastrointestinal surgery, but the pathophysiological mechanism has not been previously explored. Systemic inflammatory response and impaired glycocalyx and endothelial cells may be responsible for the development of symptoms. METHODS: The study analyzed prospectively collected data from two cohorts (n = 67). The severity of the MTS response was graded intraoperatively and blood samples for PGI2, catecholamines, IL6, and endothelial biomarkers obtained at predefined time points. RESULTS: Patients undergoing either esophagectomy (n = 45) or gastrectomy (n = 22) were included. Surgery led to significantly increased plasma concentrations of all biomarkers. Yet, patients who developed severe MTS had higher baseline epinephrine levels (p < 0.05) and higher levels of PGI2 (p < 0.05), Syndecan-1 (p < 0.001), and sVEGFR1 (p < 0.001). Peak values of IL6, Syndecan-1, sVEGFR1, and sTM all correlated to peak PGI2. Lastly, patients with high postoperative morbidity had higher baseline epinephrine (p = 0.009) and developed higher plasma IL6 (p = 0.007) and sTM (p = 0.022). CONCLUSION: The development of severe MTS during upper gastrointestinal surgery is associated with preoperative elevated plasma epinephrine and further a more pronounced proinflammatory response and damage to the vascular endothelium. The increased postoperative morbidity seen in patients with severe MTS may thus, in part, be explained by an inherent susceptibility towards an inappropriate secretion of PGI2, which leads to an increased surgical stress response and endothelial damage. These findings must be confirmed in a new prospective cohort.

The effect of prostacyclin (Iloprost) infusion at a dose of 1 ng/kg/min for 72 hours compared to placebo in mechanically ventilated patients with COVID-19: A structured summary of a study protocol for a randomized controlled trial.

OBJECTIVES: To investigate the effect of continuous infusion of the potential endothelial cytoprotective agent prostacyclin (Iloprost) 1 ng/kg/min vs. placebo for 72 hours on pulmonary endotheliopathy in mechanically ventilated COVID-19 patients. TRIAL DESIGN: A multicenter, randomized (1:1, active: placebo), blinded, parallel group exploratory trial PARTICIPANTS: Inclusion criteria are: Adult patients (>18 years); Confirmed COVID-19 infection; Need for mechanical interventions; Endothelial biomarker soluble thrombomodulin >4ng/ml. EXCLUSION CRITERIA: Withdrawal from active therapy; Pregnancy (non-pregnancy confirmed by patient being postmenopausal (age 60 or above) or having a negative urine- or plasma-hCG); Known hypersensitivity to iloprost or to any of the other ingredients; Previously included in this trial or a prostacyclin trial within 30 days; Consent cannot be obtained; Life-threatening bleeding defined by the treating physician; Known severe heart failure (NYHA class IV); Suspected acute coronary syndrome The study is conducted at five intensive care units in the Capital Region of Denmark at Rigshospitalet, Herlev Hospital, Hvidovre Hospital, Bispebjerg Hospital, Nordsjællands Hospital. INTERVENTION AND COMPARATOR: The patients are randomized to 72-hours continuous infusion of either prostacyclin (Iloprost/Ilomedin) at a dose of 1 ng/kg/min or Placebo (normal saline). MAIN OUTCOMES: Primary endpoint: Days alive without mechanical ventilation in the intensive care units within 28 days RANDOMISATION: The randomisation sequence is performed in permuted blocks of variable sizes stratified for trial site using centralised, concealed allocation. The randomisation sequence is generated 1:1 (active/placebo) using the online randomisation software 'Sealed Envelope' ( https://www.sealedenvelope.com/ ). Once generated the randomisation sequence is formatted and uploaded into Research Electronic Data Capture system (REDCap) to facilitate centralised, web-based allocation according to local written instruction. BLINDING (MASKING): The following are blinded: all clinicians, patients, investigators, and those assessing the outcomes including the statisticians. NUMBERS TO BE RANDOMISED (SAMPLE SIZE): Forty patients are planned to be randomized to each group, with a total sample size of 80 patients. TRIAL STATUS: Protocol version 1.4 dated May 25, 2020. Recruitment is ongoing. The recruitment was started June 15, 2020 and the anticipated finish of recruitment is February 28, 2021 with 90 days follow up hereafter. TRIAL REGISTRATION: Trial registration at clinicaltrialregisters.eu; EudraCT no. 2020-001296-33 on 3 April 2020 and at ClinicalTrials.gov Identifier: NCT04420741 on 9 June 2020 FULL PROTOCOL: The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1).In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol.

Use of red blood cells in Danish intensive care units: A population-based register study.

BACKGROUND: Red blood cell (RBC) transfusion is common in the intensive care unit (ICU). Recent trials have shown that a restrictive transfusion strategy is safe in most patients, and recent guidelines recommend such a strategy in most ICU patients. It is unknown if this has translated into a change in clinical practice. METHODS: We conducted a population-based register study of RBC transfusions in ICUs in the Danish Capital Region between 1st of January 2011 and 31st of December 2016 by linking data from the regional blood bank and the Danish Intensive Care Database. We used crude data and run- and control-charts to analyse changes in the number of RBC transfusions. RESULTS: We included 27 835 ICU admissions of which 6936 received 40 889 RBC units. The crude use was 36.2 RBC units per one-hundred patient bed-days in 2011 vs 29.8 in 2016. The run-chart analysis did not confirm a change in the total use of RBC units in all ICUs combined, and we observed no change in the proportion of transfused patients or in the use of RBCs among transfused patients. Sensitivity analyses showed decreased use of RBC units in two general ICUs, and a reduced use of RBC units among medical ICU patients. CONCLUSIONS: In this population-based register study, we did not with certainty observe changes over time in the use of RBC transfusions in all patients in all ICUs in the Danish Capital Region. A reduction in RBC use may have occurred in some general ICUs and in medical ICU patients.

Management of bleeding in major burn surgery.

Major burn surgery is often associated with excessive bleeding and massive transfusion, and the development of a coagulopathy during major burn surgery is associated with increased morbidity and mortality. The aim of this study was to review the literature on intraoperative haemostatic resuscitation of burn patients during necrectomy to reveal strategies applied for haemostatic monitoring and resuscitation. We searched PubMed, EMBASE, and CENTRAL for studies published in the period 2006-2017 concerning bleeding issues related to burn surgery i.e. coagulopathy, transfusion requirements and clinical outcomes. In a broad search, a total of 1375 papers were identified. 124 of these fulfilled the inclusion criteria, and six of these were included for review. The literature confirmed that transfusion requirements increases with burn injury severity and that haemostatic monitoring by TEG® (thrombelastography) or ROTEM® (rotational thromboelastometry) significantly decreased intraoperative transfusions and was useful in predicting and goal-directing haemostatic therapy during excision surgery. Resuscitation of bleeding during major burn surgery in many instances was neither standardized nor haemostatic. We suggest that resuscitation should aim for normal haemostasis during the bleeding phase through close haemostatic monitoring and resuscitation. Randomised controlled trials are highly warranted to confirm the benefit of this concept.

Time Trial Performance Is Sensitive to Low-Volume Autologous Blood Transfusion.

PURPOSE: This study tested the hypothesis that autologous blood transfusion (ABT) of ~50% of the red blood cells (RBC) from a standard 450-mL phlebotomy would increase mean power in a cycling time trial. In addition, the study investigated whether further ABT of RBC obtained from another 450-mL phlebotomy would increase repeated cycling sprint ability. METHODS: In a randomized, double-blind, placebo-controlled crossover design (3-month wash-out), nine highly trained male subjects donated two 450-mL blood bags each (BT trial) or were sham phlebotomized (PLA trial). Four weeks later, a 650-kcal time trial (n = 7) was performed 3 d before and 2 h after receiving either ~50% (135 mL) of the RBC or a sham transfusion. On the following day, transfusion of RBC (235 mL) from the second donation or sham transfusion was completed. A 4 × 30-s all-out cycling sprint interspersed by 4 min of recovery was performed 6 d before and 3 d after the second ABT (n = 9). RESULTS: The mean power was increased in time trials from before to after transfusion (P < 0.05) in BT (213 ± 35 vs 223 ± 38 W; mean ± SD) but not in PLA (223 ± 42 vs 224 ± 46 W). In contrast, the mean power output across the four 30-s sprint bouts remained similar in BT (639 ± 35 vs 644 ± 26 W) and PLA (638 ± 43 vs 639 ± 25 W). CONCLUSIONS: ABT of only ~135 mL of RBC is sufficient to increase mean power in a 650-kcal cycling time trial by ~5% in highly trained men. In contrast, a combined high-volume transfusion of ~135 and ~235 mL of RBC does not alter 4 × 30-s all-out cycling performance interspersed with 4 min of recovery.

Metabolic systems analysis of LPS induced endothelial dysfunction applied to sepsis patient stratification.

Endothelial dysfunction contributes to sepsis outcome. Metabolic phenotypes associated with endothelial dysfunction are not well characterised in part due to difficulties in assessing endothelial metabolism in situ. Here, we describe the construction of iEC2812, a genome scale metabolic reconstruction of endothelial cells and its application to describe metabolic changes that occur following endothelial dysfunction. Metabolic gene expression analysis of three endothelial subtypes using iEC2812 suggested their similar metabolism in culture. To mimic endothelial dysfunction, an in vitro sepsis endothelial cell culture model was established and the metabotypes associated with increased endothelial permeability and glycocalyx loss after inflammatory stimuli were quantitatively defined through metabolomics. These data and transcriptomic data were then used to parametrize iEC2812 and investigate the metabotypes of endothelial dysfunction. Glycan production and increased fatty acid metabolism accompany increased glycocalyx shedding and endothelial permeability after inflammatory stimulation. iEC2812 was then used to analyse sepsis patient plasma metabolome profiles and predict changes to endothelial derived biomarkers. These analyses revealed increased changes in glycan metabolism in sepsis non-survivors corresponding to metabolism of endothelial dysfunction in culture. The results show concordance between endothelial health and sepsis survival in particular between endothelial cell metabolism and the plasma metabolome in patients with sepsis.

Plasma Concentration of Biomarkers Reflecting Endothelial Cell- and Glycocalyx Damage are Increased in Patients With Suspected ST-Elevation Myocardial Infarction Complicated by Cardiogenic Shock.

BACKGROUND: Mortality in ST-elevation myocardial infarction (STEMI) patients developing cardiogenic shock (CS) during hospitalization is high. Catecholamines, ischemia, and inflammation (parameters present in CS) affect the endothelium. We hypothesized that plasma level of biomarkers reflecting endothelial damage would be associated with CS and mortality. METHODS: In 96% of 1467 consecutive patients with suspected STEMI, biomarkers reflecting endothelial cell- (soluble thrombomodulin, sTM) and glycocalyx- (syndecan-1) damage were measured on admission. Patients were stratified by CS development or not. CS-Patients were substratified by CS on admission (admission-CS), CS developed in the catheterization laboratory (cath. lab.-CS), or late CS. RESULTS: STEMI patients with admission-CS (n = 85) and cath.lab.-CS (n = 25) had higher levels of sTM and syndecan-1 compared with no-CS patients (n = 1,299). Late CS-patients (n = 58) had higher levels of sTM (median (25th; 75th percentile) 8.8 (7.0; 11.6) vs. 7.4 (6.0; 9.0) ng/mL, P = 0.0004) but not Syndecan-1 (P = 0.26) compared with no-CS patients. sTM was, however, not independently associated with late CS development (OR (95% CI) 1.07 (0.99-1.16), P = 0.09). Patients with the highest level of sTM and syndecan-1 had the highest 30-day mortality (Plogrank<0.0001). However, neither sTM nor Syndecan-1 was independently associated with 30-day mortality (HR (95% CI) sTM: 1.06 (0.996-1.12), P = 0.07; Syndecan-1: 1.04 (0.99-1.08), P = 0.12). CONCLUSION: Patients with suspected STEMI patients and admission-CS/cath.lab.-CS had elevated admission levels of sTM and Syndecan-1 compared with no CS patients. Patients developing late CS had higher sTM plasma concentration compared with patients without shock. However, the biomarker levels were not independently associated with late CS and mortality.

Effects of propranolol and clonidine on brain edema, blood-brain barrier permeability, and endothelial glycocalyx disruption after fluid percussion brain injury in the rat.

BACKGROUND: Traumatic brain injury causes a disruption of the vascular endothelial glycocalyx layer that is associated with an overactivation of the sympathoadrenal system. We hypothesized that early and unselective beta-blockade with propranolol alone or in combination with the alfa2-agonist clonidine would decrease brain edema, blood-brain barrier permeability, and glycocalyx disruption at 24 hours after trauma. METHODS: We subjected 53 adult male Sprague-Dawley rats to lateral fluid percussion brain injury and randomized infusion with propranolol (n = 16), propranolol + clonidine (n = 16), vehicle (n = 16), or sham (n = 5) for 24 hours. Primary outcome was brain water content at 24 hours. Secondary outcomes were blood-brain barrier permeability and plasma levels of syndecan-1 (glycocalyx disruption), cell damage (histone-complexed DNA fragments), epinephrine, norepinephrine, and animal motor function. RESULTS: We found no difference in brain water content (mean ± SD) between propranolol (80.8 ± 0.3%; 95% confidence interval [CI], 80.7-81.0) and vehicle (81.1 ± 0.6%; 95% CI, 80.8-81.4) (p = 0.668) or between propranolol/clonidine (80.8 ± 0.3%; 95% CI, 80.7-81.0) and vehicle (p = 0.555). We found no effect of propranolol and propranolol/clonidine on blood-brain barrier permeability and animal motor scores. Unexpectedly, propranolol and propranolol/clonidine caused an increase in epinephrine and syndecan-1 levels. CONCLUSION: This study does not provide any support for unselective beta-blockade with propranolol or the combination of propranolol and the alfa2-agonist clonidine on brain water content. The novel finding of an increase in plasma concentrations of epinephrine and syndecan-1 after propranolol treatment in traumatic brain injury is of unclear significance and should be investigated further.

Transfusion requirements in elective cardiopulmonary bypass surgery patients: predictive value of Multiplate and Thromboelastography (TEG) Platelet Mapping Assay.

Managing haemostasis in patients undergoing cardiopulmonary bypass (CPB) surgery remains a challenge. There is no established laboratory test to predict transfusion requirements in cardiac surgery. We investigated whether preoperative Thromboelastography (TEG) with Platelet Mapping Assay (PMA) or Multiple Electrode Aggrometry (MEA) could predict transfusion requirements in patients undergoing elective coronary artery bypass grafting (CABG) or combined CABG with aortic or mitral valve replacement. We prospectively investigated 199 patients undergoing elective CABG or combined procedures. PMA and MEA were performed at baseline (after anaesthesia induction), upon arrival at the intensive care unit and on the first postoperative day. Patients receiving fresh frozen plasma and/or platelets (FFP/PLT) had a lower PMA maximum amplitude (MA) for adenosine diphosphate (PMA-ADP) and arachidonic acid (PMA-AA) at baseline, at arrival in the intensive care unit and the first postoperative day compared to non-transfused patients. Receiver operating characteristic curves on PMA showed that lower values predicted FFP/PLT transfusion: PMA-ActF 0.64 (p = 0.04), PMA-ADP 0.69 (p = 0.01) and PMA-AA 0.71 (p = 0.002). In contrast, MEA values were not able to predict FFP/PLT transfusions. This study shows that preoperative PMA potentially is a better screening tool for platelet inhibition associated with transfusion requirements in patients undergoing CABG or combined procedures.