Severe pulmonary embolism decreases plasma L-arginine

The Association Between Mean Corpuscular Hemoglobin Concentration and Prognosis in Patients with Acute Pulmonary Embolism: A Retrospective Cohort Study

Introduction

Acute pulmonary embolism (APE) is a typical cardiovascular emergency worldwide. Mean hemoglobin concentration (MCHC) is a standard indicator of anemia. Studies on the association between MCHC and APE are scarce. We aimed to investigate the relationship between MCHC and APE.

Methods

Clinical data were extracted from the Medical Information Bank for Intensive Care (MIMIC)-III. Adult (≥18 years) patients with APE admitted for the first time were included in this study. An analysis was conducted to evaluate the association between MCHC and the prognosis of patients by the Cox regression analysis, generalized additives models and Kaplan–Meier survival curves. The primary outcome was 30-day mortality, and the secondary outcomes were 1-year and 3-year mortality.

Results

A total of 813 patients who met the selection criteria were enrolled, of whom 130 (16.0%) died within 30 days of admission. Univariate Cox regression indicated that MCHC was significantly associated with mortality (30-day: HR = 0.74, 95% CI = 0.66–0.82, P < 0.001; 1-year: HR = 0.80, 95% CI = 0.74–0.86, P < 0.001; 3-year: HR = 0.82, 95% CI = 0.77–0.88, P < 0.001). MCHC remains stable after adjusting multiple models. Kaplan-Meier survival curves showed that patients with lower MCHC had a poorer 30-day prognosis.

Conclusions

Lower MCHC is an independent risk factor for increased mortality in patients with APE. As an inexpensive biomarker, MCHC should receive more attention.

Inhaled nitric oxide to control platelet hyper-reactivity in patients with acute submassive pulmonary embolism

BACKGROUND

We test if inhaled nitric oxide (NO) attenuates platelet functional and metabolic hyper-reactivity in subjects with submassive pulmonary embolism (PE).

METHODS

Participants with PE were randomized to either 50 ppm NO + O2 or O2 only for 24 h with blood sampling at enrollment and after treatment; results were compared with healthy controls. Platelet metabolic activity was assessed by oxygen consumption (basal and uncoupled) and reactivity was assessed with agonist-stimulated thromboelastography (TEG) and fluorometric measurement of agonist-stimulated cytosolic [Ca⁺⁺] without and with pharmacological soluble guanylate (sGC) modulation.

RESULTS

Participants (N = 38 per group) were well-matched at enrollment for PE severity, comorbidities as well as TEG parameters and platelet O2 consumption. NO treatment doubled the mean plasma [NO3-] (P < 0.001) indicating successful delivery, but placebo treatment produced no change. After 24 h, neither TEG nor O2 consumption parameters differed significantly between treatment groups. Platelet cytosolic [Ca⁺⁺] was elevated with PE versus controls, and was decreased by treatment with cinaciguat (an sGC activator), but not riociguat (an sGC stimulator). Stimulated platelet lysate sGC activity was increased with PE compared with controls.

CONCLUSIONS

In patients with acute submassive PE, despite evidence of adequate drug delivery, inhaled NO had no major effect on platelet O2 consumption or agonist-stimulated parameters on TEG. Pharmacological activation, but not stimulation, of sGC effectively decreased platelet cytosolic [Ca⁺⁺], and platelet sGC activity was increased with PE, confirming the viability of sGC as a therapeutic target.

Effect of In Ovo Injection of L-Arginine in Different Chicken Embryonic Development Stages on Post-Hatchability, Immune Response, and Myo-D and Myogenin Proteins

Simple Summary

In the current study, we hypothesized that the in ovo injection of L-arginine (L-Arg) at different stages of embryonic development, which would have positive effects on the survival rate, hatching rate, immunoglobulin M (IgM) levels, heat shock proteins (HSPs) such as HSP-47, HSP-60, and HSP-70, and muscle development markers as well: Mainly, myoblast determination protein (myoD) and myogenin in pectoral muscles. As indicated, the in ovo injection of L-Arg resulted in an increased hatch rate and weight, survival rate, higher levels of IgM, and myogenin and MyoD expression in the muscles. At the same time, a decrease in the level of HSP-47, HSP-60, and HSP-70 expressions in the tissues was observed on the 14th day of injection compared to the eighth and 18th day of the injection period. In addition, the in ovo injection of L-Arg decreased the serum glutamate oxaloacetate transaminase (SGOT) and serum glutamate pyruvate transaminase (SGPT) concentration in serum as well micronuclei and nuclear abnormality in the blood on the 14th day of the incubation period. Hence, the 14th day would be a suitable day for the injection of L-Arg to promote the hatching rate and muscle growth of broiler chickens.

Abstract

The aim of this study was to evaluate the effect of in ovo injection with different ratios of L-arginine (L-Arg) into Ross broiler eggs at three different embryonic developmental stages (eighth day (d), 14th day, and 18th day) on the survival, hatchability, and body weight (BW) of one-day-old hatched chicks. Additionally, we have analyzed the levels of serum glutamate oxaloacetate transaminase (SGOT) and serum glutamate pyruvate transaminase (SGPT), the protein expression of heat shock proteins (HSPs), and we have also determined micronuclei (MN) and nuclear abnormality (NA). In addition, the genotoxic effect was observed in peripheral blood cells such as the presence of micronuclei and nuclear abnormalities in the experimental groups. The results showed that survival and hatching rates as well as body weight were increased on the 14th day of incubation compared to the eighth and 18th day of incubation at lower concentrations of L-Arg. Moreover, the levels of SGOT and SGPT were also significantly (p < 0.05) increased on the 14th day of incubation at the same concentration (100 μg/μL/egg) of injection. In addition, immunoglobulin (IgM) levels were increased on the 14th day of incubation compared to other days. The protein expressions of HSP-47, HSP-60, and HSP-70 in the liver were significantly down-regulated, whereas the expression of myogenin and myoblast determination protein (MyoD) were significantly up-regulated on the 14th day after incubation when treated with all different doses such as 100 μg, 1000 μg, and 2500 μg/μL/egg, namely 3T1, 3T2, and 3T3, respectively. However, the treatment with low doses of L-Arg down-regulated the expression levels of those proteins on the 14th day of incubation. Histopathology of the liver by hematoxylin and eosin (H&E) staining showed that the majority of liver damage, specifically intracytoplasmic vacuoles, were observed in the 3T1, 3T2, and 3T3 groups. The minimum dose of 100 μg/mL/egg on the 14th day of incubation significantly prevented intracytoplasmic vacuole damages. These results demonstrate that in ovo administration of L-Arg at (100 μg/μL/egg) may be an effective method to increase chick BW, hatch rate, muscle growth-related proteins, and promote the immune response through increasing IgM on the 14th day of the incubation period.

Inhaled Nitric Oxide as an Adjunct to Thrombolytic Therapy in a Patient with Submassive Pulmonary Embolism and Severe Hypoxemia

Introduction

Inhaled nitric oxide (iNO) is a selective pulmonary vasodilator with limited indications in adults. We present a patient with hypoxemia and right ventricular dysfunction due to submassive acute pulmonary emboli where iNO was used as a bridge to thrombolysis.

Case

A 29-year-old male was admitted to the intensive care unit (ICU) for alcohol intoxication complicated with aspiration pneumonia and acute respiratory failure requiring mechanical ventilation. His medical history included morbid obesity (BMI 43) and alcohol dependence syndrome. Nine days after admission, he developed severe acute hypoxia and tachycardia with arterial oxygen tension (PaO2) of 52 mmHg requiring a positive end-expiratory pressure (PEEP) of 14 cmH2O and fraction of inspired oxygen (FiO2) of 1. Chest computed tomography (CT) revealed a large embolus in the right main pulmonary artery and transthoracic echocardiogram (TTE) reported new right ventricular dilatation with decreased right ventricular function. Due to the severe hypoxemia, he was started on iNO via the breathing circuit of the ventilator at a concentration of 20 parts per million (ppm) with steady improvement in oxygenation after 1 hour with a PaO2 of 81 mmHg on the same ventilator setting. The patient was given thrombolysis with alteplase and the iNO was slowly tapered off during the subsequent four days with concomitant successful tapering of PEEP to 8 cmH2O and FiO2 of 0.45.

Conclusion

Inhaled NO has been used to improve ventilation-perfusion matching and also to reduce pulmonary vascular resistance (PVR). Its effects on PVR may be useful in the setting of acute pulmonary emboli where vascular obstruction and vasoconstriction contribute to increased pulmonary arterial pressure and PVR which can present as acute right heart failure. We suggest that iNO, if available, could be considered in those patients with acute pulmonary emboli associated with significant hypoxemia as an adjunctive therapy or bridge to thrombolysis or thrombectomy.

Inhaled nitric oxide to treat intermediate risk pulmonary embolism: A multicenter randomized controlled trial

OBJECTIVE

To test the hypothesis that adjunctive inhaled NO would improve RV function and viability in acute PE.

METHODS

This was a randomized, placebo-controlled, double blind trial conducted at four academic hospitals. Eligible patients had acute PE without systemic arterial hypotension but had RV dysfunction and a treatment plan of standard anticoagulation. Subjects received either oxygen plus 50 parts per million nitrogen (placebo) or oxygen plus 50 ppm NO for 24 h. The primary composite endpoint required a normal RV on echocardiography and a plasma troponin T concentration <14 pg/mL. The secondary endpoint required a blood brain natriuretic peptide concentration <90 pg/mL and a Borg dyspnea score ≤ 2. The sample size of N = 76 tested if 30% more patients treated with NO would achieve the primary endpoint with 80% power and alpha = 5%.

RESULTS

We randomized 78 patients and after two withdrawals, 38 were treated per protocol in each group. Patients were well matched for baseline conditions. At 24 h, 5/38 (13%) of patients treated with placebo and 9/38 (24%) of patients treated with NO reached the primary endpoint (P = 0.375). The secondary endpoint was reached in 34% with placebo and 13% of the NO (P = 0.11). In a pre-planned post-hoc analysis, we examined how many patients with RV hypokinesis or dilation at enrollment resolved these abnormalities; 29% more patients treated with NO resolved both abnormalities at 24 h (P = 0.010, Cochrane's Q test).

CONCLUSIONS

In patients with severe submassive PE, inhaled nitric oxide failed to increase the proportion of patients with a normal troponin and echocardiogram but increased the probability of eliminating RV hypokinesis and dilation on echocardiography.

CLINICAL TRIAL REGISTRATION

NCT01939301.

Platelet hyperactivation, apoptosis and hypercoagulability in patients with acute pulmonary embolism

Changes in systemic redox balance can alter platelet activation and aggregation. Acute pulmonary embolism (PE) is a systematic inflammatory disease associated with mechanical shear stress, increased thrombin, catecholamines, serotonin and hemolysis, which cumulatively can hyperactivate platelets and accelerate their turnover. We tested the hypothesis that platelets from patients with moderately severe PE will show hyperstimulation and a pre-apoptotic phenotype associated with microparticles (MPs) in plasma. Blood for platelet respiration and thromboelastography (TEG) was obtained at diagnosis and 24h later from patients (n=76) with image-proven PE, SBP>90mmHg and right ventricular dysfunction demonstrated by echocardiogram or elevated biomarkers. Controls (n=12) were healthy volunteers. At diagnosis, platelets from PE patients had significantly elevated baseline oxygen consumption compared with controls, explained primarily by accelerated electron transport and oxygen wasting with no measurable extramitochondrial oxygen consumption. On thromboelastography, unstimulated thrombin-independent maximum amplitude was increased with PE, 19±14.1 vs.10.5±7.8mm in controls (p=0.002). Compared with controls, platelets from PE patients showed elevated mitochondrial reactive oxygen species with decreased mitochondrial Bcl-2 protein content and increased cytosolic cytochrome C, coincident with strong annexin V binding, P selectin release from lysed platelets and in plasma MPs compared to controls (p<0.05). These results show evidence of platelet hyperactivation and apoptosis in patients with acute PE, and provide preliminary theoretical basis for further exploration of platelet inhibition in patients with more severe PE.

Randomized trial of inhaled nitric oxide to treat acute pulmonary embolism: The iNOPE trial

BACKGROUND

The study hypothesis is that administration of inhaled nitric oxide (NO) plus oxygen to subjects with submassive pulmonary embolism (PE) will improve right ventricular (RV) systolic function and reduce RV strain and necrosis, while improving patient dyspnea, more than treatment with oxygen alone.

METHODS

This article describes the rationale and protocol for a registered (NCT01939301), nearly completed phase II, 3-center, randomized, double-blind, controlled trial. Eligible patients have pulmonary imaging-proven acute PE. Subjects must be normotensive, and have RV dysfunction on echocardiography or elevated troponin or brain natriuretic peptide and no fibrinolytics. Subjects receive NO plus oxygen or placebo for 24 hours (±3 hours) with blood sampling before and after treatment, and mandatory echocardiography and high-sensitivity troponin posttreatment to assess the composite primary end point. The sample size of N=78 was predicated on 30% more NO-treated patients having a normal high-sensitivity troponin (<14 pg/mL) and a normal RV on echocardiography at 24 hours with α=.05 and β=.20. Safety was ensured by continuous spectrophotometric monitoring of percentage of methemoglobinemia and a predefined protocol to respond to emergent changes in condition. Blinding was ensured by identical tanks, software, and physical shielding of the device display and query of the clinical care team to assess blinding efficacy.

RESULTS

We have enrolled 78 patients over a 31-month period. No patient has been withdrawn as a result of a safety concern, and no patient has had a serious adverse event related to NO.

CONCLUSIONS

We present methods and a protocol for the first double-blinded, randomized trial of inhaled NO to treat PE.

Development, validation, and comparison of four methods to simultaneously quantify l-arginine, citrulline, and ornithine in human plasma using hydrophilic interaction liquid chromatography and electrospray tandem mass spectrometry

To understand the role of l-arginine depletion in impaired nitric oxide synthesis in disease, it is important to simultaneously quantify arginine, citrulline, and ornithine in the plasma. Because the three amino acids are endogenous analytes, true blank matrix for them is not available. It is necessary and valuable to compare the performance of different approaches due to lack of regulatory clarity for validation. A two-step sample preparation method using methanol as protein precipitation reagent was developed in this study is used for sample preparation. Because true blank matrix for endogenous analytes is not available, water as blank matrix, 1% BSA in PBS as blank matrix, surrogate analyte, and background subtraction were designed to establish successful quantification methods. Four methods to simultaneously quantify arginine, citrulline, and ornithine in human plasma using hydrophilic interaction liquid chromatography and electrospray tandem mass spectrometry were developed, validated, and compared. The developed two-step sample preparation method using methanol as protein precipitation reagent in this study needs less time and provides higher recovery comparing with other approaches. Three of the four methods, water as blank matrix, 1% BSA in PBS as blank matrix, and surrogate analyte, have been successful in fulfilling all the criteria, while background subtraction has failed. Results of the measured concentrations in 97 human plasma samples using the three methods show that the difference between any two methods or among the three methods presents 100% of samples with less than 20% for all the three amino acids and majority of them are under 10%. The developed two-step sample preparation method using methanol as protein precipitation reagent is simple and convenient. Three of the four methods are fully validated and the validation is successful. The BSA functioned effectively as a blank matrix for these three amino acids, considering cost, data quality, matrix similarity, and practicality.

Leukocyte expression of heme oxygenase-1 [hmox1] varies inversely with severity of tricuspid regurgitation in acute pulmonary embolism

OBJECTIVE

Pulmonary embolism (PE) can cause intracardiac hemolysis and increased plasma hemoglobin and arginase-1, which can worsen pulmonary vasoconstriction. We test the hypothesis that patients with PE that causes tricuspid regurgitation (TR), indicative of higher pulmonary arterial pressures, have decreased leukocyte expression of hmox-1 compared with patients with PE and no TR and patients without PE.

DESIGN

Prospective, noninterventional study.

PATIENTS

Normotensive patients with suspected PE (n=87) who underwent CT pulmonary angiography and transthoracic Doppler-echocardiography.

MEASUREMENTS

Significant TR was defined as a jet velocity >2.7m/s. Leukocyte expression of hmox-1, haptoglobin, haptoglobin related gene, the haptoglobin receptor, CD163 and cox-2 genes were assessed by quantitative rtPCR, and the hmox-1 promoter was examined for the -413 A→T SNP and GT repeat polymorphisms.

RESULTS

Of the 44 (50%) with PE+, 22 had TR+, and their mean pulmonary vascular occlusion (39±32%) did not differ significantly from patients who were TR- (28±26%, P=0.15). Patients with PE+ and TR+ had significantly lower expression of hmox-1 and haptoglobin genes than patients without PE+ and no TR. Expression of hmox-1 varied inversely with TR velocity (r(2)=0.45, P<0.001) for PE+ (n=22) but not patients without PE. Hmox-1 expression did not vary significantly with genotype. Cox-2 did not differ between groups and had no correlation with TR.

CONCLUSIONS

Severity of TR varied inversely with hmox-1 expression, suggesting that hmox-1 expression affects pulmonary vascular reactivity after PE.