Bacterial sepsis causes more dramatic pathogenetic changes in the Th1 pathway than does viral (COVID-19) sepsis: a prospective observational study of whole blood transcriptomes.

OBJECTIVES: This study aimed to comprehensively compare host responses of patients with bacterial sepsis and those with viral (COVID-19) sepsis by analyzing messenger RNA (mRNA) and microRNA (miRNA) profiles to shed light on their distinct pathophysiological mechanisms. DESIGN: Prospective observational study. SETTING: Whole blood RNA sequencing was used to analyze mRNA and miRNA profiles of patients diagnosed as having bacterial sepsis or viral (COVID-19) sepsis at the Department of Trauma and Emergency Medicine, Osaka University Graduate School of Medicine. PATIENTS: Twenty-two bacterial sepsis patients, 35 viral (COVID-19) sepsis patients, and 15 healthy subjects admitted to the department were included. We diagnosed bacterial sepsis patients according to the sepsis-3 criterion that the Sequential Organ Failure Assessment score must increase to 2 points or more among patients with suspected infections. Viral (COVID-19) sepsis patients were diagnosed using SARS-CoV-2 RT-PCR testing, and presence of pneumonia was assessed through chest computed tomography scans. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: For RNA sequencing, 14,500 mRNAs, 1121 miRNAs, and 2556 miRNA-targeted mRNAs were available for analysis in the bacterial sepsis patients. Numbers of genes showing upregulated: downregulated gene expression (false discovery rate < 0.05, |log2 fold change| > 1.5) were 256:2887 for mRNA, 53:5 for miRNA, and 49:2507 for miRNA-targeted mRNA. Similarly, in viral (COVID-19) sepsis patients, 14,500 mRNAs, 1121 miRNAs, and 327 miRNA-targeted mRNAs were analyzed, with numbers of genes exhibiting upregulated: downregulated gene expression of 672:1147 for mRNA, 3:4 for miRNA, and 165:162 for miRNA-targeted mRNA. This analysis revealed significant differences in the numbers of upregulated and downregulated genes expressed and pathways between the bacterial sepsis and viral (COVID-19) sepsis patients. Bacterial sepsis patients showed activation of the PD-1 and PD-L1 cancer immunotherapy signaling pathway and concurrent suppression of Th1 signaling. CONCLUSION: Our study illuminated distinct molecular variances between bacterial sepsis and viral (COVID-19) sepsis. Bacterial sepsis patients had a greater number of upregulated and downregulated genes and pathways compared to viral (COVID-19) sepsis patients. Especially, bacterial sepsis caused more dramatic pathogenetic changes in the Th1 pathway than did viral (COVID-19) sepsis.

Atypical and non-classical CD45RBlo memory B cells are the majority of circulating SARS-CoV-2 specific B cells following mRNA vaccination or COVID-19.

Resting memory B cells can be divided into classical or atypical groups, but the heterogenous marker expression on activated memory B cells makes similar classification difficult. Here, by longitudinal analysis of mass cytometry and CITE-seq data from cohorts with COVID-19, bacterial sepsis, or BNT162b2 mRNA vaccine, we observe that resting B cell memory consist of classical CD45RB+ memory and CD45RBlo memory, of which the latter contains of two distinct groups of CD11c+ atypical and CD23+ non-classical memory cells. CD45RB levels remain stable in these cells after activation, thereby enabling the tracking of activated B cells and plasmablasts derived from either CD45RB+ or CD45RBlo memory B cells. Moreover, in both COVID-19 patients and mRNA vaccination, CD45RBlo B cells formed the majority of SARS-CoV2 specific memory B cells and correlated with serum antibodies, while CD45RB+ memory are activated by bacterial sepsis. Our results thus identify that stably expressed CD45RB levels can be exploited to trace resting memory B cells and their activated progeny, and suggest that atypical and non-classical CD45RBlo memory B cells contribute to SARS-CoV-2 infection and vaccination.

T cell dysfunction in elderly ARDS patients based on miRNA and mRNA integration analysis.

Background: Acute respiratory distress syndrome (ARDS) is respiratory failure that commonly occurs in critically ill patients, and the molecular mechanisms underlying its pathogenesis and severity are poorly understood. We evaluated mRNA and miRNA in patients with ARDS and elucidated the pathogenesis of ARDS after performing mRNA and miRNA integration analysis. Methods: In this single-center, prospective, observational clinical study of patients with ARDS, peripheral blood of each patient was collected within 24 hours of admission. Sequencing of mRNA and miRNA was performed using whole blood from the ARDS patients and healthy donors. Results: Thirty-four ARDS patients were compared with 15 healthy donors. Compared with the healthy donors, 1233 mRNAs and 6 miRNAs were upregulated and 1580 mRNAs and 13 miRNAs were downregulated in the ARDS patients. For both mRNA and miRNA-targeted mRNA, canonical pathway analysis showed that programmed death-1 (PD-1) and programmed cell death ligand 1 (PD-L1) cancer immunotherapy pathway was most activated and the Th2 pathway was most suppressed. For mRNA, the Th1 pathway was most suppressed. miR-149-3p and several miRNAs were identified as upstream regulators. Conclusion: miRNAs regulated the PD-1 and PD-L1 cancer immunotherapy pathway and Th2 pathway through miRNA interference action of mRNA. Integrated analysis of mRNAs and miRNAs showed that T cells were dysfunctional in ARDS patients.

Classification of patients with COVID-19 by blood RNA endotype: a prospective cohort study.

IMPORTANCE: In this study, whole-blood RNAs (prolactin and toll-like receptor 3) involved in the prognosis of patients with COVID-19 were identified. The RNA endotypes classified by these important RNAs highlight the possibility of stratifying the COVID-19 patient population and the need for targeted therapy based on these phenotypes.

Association between high cardiac output at altitude and acute mountain sickness: preliminary study on Mt. Fuji.

BACKGROUND: Acute mountain sickness (AMS) affects around 30% of people climbing Mt. Fuji, but its pathogenesis is incompletely understood. The influence of a rapid ascent to high altitude by climbing and summiting Mt. Fuji on cardiac function in the general population is unknown, and its association with altitude sickness has not been clarified. METHODS: Subjects climbing Mt. Fuji were included. Heart rate, oxygen saturation, systolic blood pressure, cardiac index (CI) and stroke volume index were measured multiple times at 120 m as baseline values and at Mt. Fuji Research Station (MFRS) at 3,775 m. Each value and its difference from the baseline value (Δ) of subjects with AMS (defined as Lake Louise Score [LLS] ≥ 3 with headache after sleeping at 3,775 m) were compared with those of non-AMS subjects. RESULTS: Eleven volunteers who climbed from 2,380 m to MFRS within 8 h and stayed overnight at MFRS were included. Four suffered AMS. Compared with the non-AMS subjects, CI in the AMS subjects was significantly higher than that before sleeping (median [interquartile range]: 4.9 [4.5, 5.0] vs. 3.8 [3.4, 3.9] mL/min/m2; p = 0.04), and their ΔCI was significantly higher before sleeping (1.6 [1.4, 2.1] vs. 0.2 [0.0, 0.7] mL/min/m2; p < 0.01) and after sleeping (0.7 [0.3, 1.7] vs. -0.2 [-0.5, 0.0] mL/min/m2; p < 0.01). ΔCI in the AMS subjects dropped significantly after sleeping versus before sleeping (3.8 [3.6, 4.5] vs. 4.9 [4.5, 5.0] mL/min/m2; p = 0.04). CONCLUSIONS: Higher values of CI and ΔCI were observed at high altitude in the AMS subjects. A high cardiac output might be associated with the development of AMS.

Residual persistence of cytotoxicity lymphocytes and regulatory T cells in patients with severe coronavirus disease 2019 over a 1-year recovery process.

Aim: To clarify the immune cellular changes in critically ill patients recovering from coronavirus disease 2019 (COVID-19). Methods: The immune response of peripheral blood mononuclear cells from patients with severe COVID-19 in different stages of recovery (3, 6, and 12 months from hospitalization) was evaluated by single-cell mass cytometry. Immunological changes in patients were compared with those in age-matched healthy donors. Results: Three patients with severe COVID-19 were compared with four healthy donors. In the patients, there was an increase in the cell density of CD4- and CD8-positive T lymphocytes, and B cells, over the course of the recovery period. CD4- and CD8-positive T lymphocytes expressing T-bet and granzyme B (Gzm B) in patients were abundant during all recovery periods. The level of regulatory T cells remained high throughout the year. The levels of natural killer (NK) cells in patients were higher than in those in the healthy donors, and the frequency of CD16+ NK cells expressing Gzm B increased throughout the year. Conclusion: Patients recovering from severe COVID-19 showed persistence of cytotoxic lymphocytes, NK cells, and regulatory T cells throughout the posthospitalization year of recovery.

Significance of interferon signaling based on mRNA-microRNA integration and plasma protein analyses in critically ill COVID-19 patients.

We evaluated mRNA and miRNA in COVID-19 patients and elucidated the pathogenesis of COVID-19, including protein profiles, following mRNA and miRNA integration analysis. mRNA and miRNA sequencing was done on admission with whole blood of 5 and 16 healthy controls (HCs) and 10 and 31 critically ill COVID-19 patients (derivation and validation cohorts, respectively). Interferon (IFN)-α2, IFN-ß, IFN-γ, interleukin-27, and IFN-λ1 were measured in COVID-19 patients on admission (day 1, 181 critical/22 non-critical patients) and days 6-8 (168 critical patients) and in 19 HCs. In the derivation cohort, 3,488 mRNA and 31 miRNA expressions were identified among differentially expressed RNA expressions in the patients versus those in HCs, and 2,945 mRNA and 32 miRNA expressions in the validation cohort. Canonical pathway analysis showed the IFN signaling pathway to be most activated. The IFN-ß plasma level was elevated in line with increased severity compared with HCs, as were IFN-ß downstream proteins, such as interleukin-27. IFN-λ1 was higher in non-critically ill patients versus HCs but lower in critical than non-critical patients. Integration of mRNA and miRNA analysis showed activated IFN signaling. Plasma IFN protein profile revealed that IFN-ß (type I) and IFN-λ1 (type III) played important roles in COVID-19 disease progression.

Effectiveness of high-flow nasal cannula for tracheal intubation in the emergency department.

BACKGROUND: Tracheal intubation in the emergency department (ED) can cause serious complications. Available evidence on the use of a high-flow nasal cannula (HFNC) during intubation in the ED is limited. This study evaluated the effect of oxygen therapy by HFNC on oxygen desaturation during tracheal intubation in the ED. METHODS: This was a single-center before-and-after study designed to compare two groups that received oxygen therapy during intubation: one received conventional oxygen, and the other received oxygen therapy using HFNC. We included non-trauma patients who required tracheal intubation in the ED. Linear regression analysis was performed to evaluate the relationship between oxygen therapy using HFNC and the lowest peripheral oxygen saturation (SpO2) during intubation in the conventional and HFNC groups. RESULTS: The study population included 87 patients (conventional group, n = 67; HFNC group, n = 20). The median lowest SpO2 in the HFNC group was significantly higher than that in the conventional group (94% [84-99%] vs. 85% [76-91%], p = 0.006). The percentage of cases with oxygen desaturation to < 90% during the intubation procedure in the HFNC group was significantly lower than that in the conventional group (40% vs. 63.8%, p = 0.037). The use of HFNC was significantly associated with the lowest SpO2, and the use of HFNC increased the lowest SpO2 during intubation procedures by 3.658% (p = 0.048). CONCLUSION: We found that the use of HFNC during tracheal intubation was potentially associated with a higher lowest SpO2 during the procedure in comparison to conventional oxygen administration in non-trauma patients in the ED.

Sepsis-associated hypoglycemia on admission is associated with increased mortality in intensive care unit patients.

AIM: Hyperglycemia is a common response to acute illness, but it is not often seen in critical conditions. The frequency and cause of hypoglycemia in septic patients have not been well elucidated. In this study, we focused on sepsis-associated hypoglycemia in the early phase and evaluated the impact of hypoglycemia on mortality. METHODS: We performed a retrospective review of 265 patients with sepsis admitted to a tertiary medical center. Blood glucose levels on admission were evaluated and analyzed by a Cox proportional hazard model. RESULTS: We categorized patients with sepsis into five groups according to blood glucose levels. Seven patients (2.6%) were admitted with severe hypoglycemia (≤40 mg/dL), 19 (7.2%) with mild hypoglycemia (41-70 mg/dL), 103 (38.9%) with euglycemia (71-140 mg/dL), 58 (21.9%) with mild hyperglycemia (141-180 mg/dL), and 78 (29.4%) with hyperglycemia (>180 mg/dL). There was a significant difference in 28-day mortality between those with severe hypoglycemia and euglycemia (71.4% versus 8.7%; P < 0.05). We analyzed the hazard ratios for the groups (relative to the reference of euglycemia) adjusted for sex, age, and Acute Physiology and Chronic Health Evaluation II and Sequential Organ Failure Assessment scores on admission. The hazard ratios for 28-day mortality in patients with severe hypoglycemia and mild hypoglycemia compared with that in patients with euglycemia were 8.18 (95% confidence interval [CI], 2.39-27.96; P = 0.001) and 7.56 (95% CI, 2.96-19.35; P < 0.001), respectively. CONCLUSION: Septic patients with severe hypoglycemia had significantly higher mortality compared with patients with euglycemia.

The accuracy of contrast-enhanced computed tomography scans to detect postpartum haemorrhage: an observational study.

INTRODUCTION: Postpartum haemorrhage is a major cause of maternal mortality. Although contrast-enhanced computed tomography (CE-CT) is useful to reveal arterial bleeding, its accuracy in postpartum haemorrhage is unclear. The aim of this study was to evaluate the accuracy of CE-CT scanning in detecting postpartum haemorrhage. METHODS: This was a retrospective observational study. We included patients with postpartum haemorrhage treated by emergency physicians in collaboration with obstetricians. We calculated the sensitivity, specificity, and positive and negative predictive values for CE-CT scanning to detect arterial bleeding. RESULTS: CE-CT scanning was performed in 52 patients, and 31 patients had extravasation. The sensitivity of CE-CT scanning to detect arterial extravasation was 100% (15/15), specificity was 28.6% (2/7), positive predictive value was 75% (15/20), and negative predictive value was 100% (2/2). CONCLUSION: We showed the sensitivity of CE-CT scanning to detect arterial extravasation in patients with postpartum haemorrhage to be 100%.

Non-linear and Interaction Analyses of Biomarkers for Organ Dysfunctions as Predictive Markers for Sepsis: A Nationwide Retrospective Study.

The Sequential Organ Failure Assessment (SOFA) score is predominantly used to assess the severity of organ dysfunction in sepsis. However, differences in prognostic value between SOFA subscores have not been sufficiently evaluated. This retrospective observational study used a large-scale database containing about 30 million patients. Among them, we included 38,869 adult patients with sepsis from 2006 to 2019. The cardiovascular and neurological subscores were calculated by a modified method. Associations between the biomarkers of the SOFA components and mortality were examined using restricted cubic spline analyses, which showed that an increase in the total modified SOFA score was linearly associated with increased mortality. However, the prognostic association of subscores varied widely: platelet count showed a J-shaped association, creatinine showed an inverted J-shaped association, and bilirubin showed only a weak association. We also evaluated interaction effects on mortality between an increase of one subscore and another. The joint odds ratios on mortality of two modified SOFA subscores were synergistically increased compared to the sum of the single odds ratios, especially in cardiovascular-neurological, coagulation-hepatic, and renal-hepatic combinations. In conclusion, total modified SOFA score was associated with increased mortality despite the varied prognostic associations of the subscores, possibly because interactions between subscores synergistically enhanced prognostic accuracy.

Energy expenditure and oxygen uptake kinetics in critically ill elderly patients.

BACKGROUND: Resting energy expenditure (REE) measurement of critically ill patients is essential for better nutrition management. Younger people increase their oxygen delivery ( ḊO2${\dot{{\rm{D}}}}{{\rm{O}}_2}$ ) to meet energy demands, but few reports have investigated oxygen uptake kinetics in elderly patients, which are the main target population in today's intensive care units (ICUs). In this study, we evaluated REE, ḊO2${\dot{{\rm{D}}}}{{\rm{O}}_2}$ , and oxygen extraction ratio (O2 Ext: oxygen consumption [ V̇O2${\dot{{\rm{V}}}}{{\rm{O}}_2}$ ]/ ḊO2${\dot{{\rm{D}}}}{{\rm{O}}_2}$ ) to clarify appropriate energy needs and consumption in elderly ICU patients. METHODS: This retrospective observational study included ventilated ICU patients who were divided into elderly participants (age ≥ 65 years) and nonelderly participants (age ≤64 years). V̇O2${\dot{{\rm{V}}}}{{\rm{O}}_2}$ , CO2 production, and cardiac output were measured by indirect calorimetry and noninvasive hemodynamic monitoring for up to 5 days. The initial values of REE, ḊO2${\dot{{\rm{D}}}}{{\rm{O}}_2}$ , and O2 Ext were compared between elderly and nonelderly patients. RESULTS: This study included 102 patients, of whom 52% (n = 53) were elderly. The absolute deviation of measured REE per ideal body weight (IBW) was significantly higher in elderly than in nonelderly patients (9.3 ± 6.9 vs 6.3 ± 6.6 kcal/kg; P < .01). ḊO2${\dot{{\rm{D}}}}{{\rm{O}}_2}$ had a strong negative correlation with age (P < .01). The O2 Ext value was significantly higher in elderly than in nonelderly patients (37 ± 19% vs 29 ± 13%; P = .03). CONCLUSIONS: Elderly critically ill patients were characterized by higher deviations in REE, lower ḊO2${\dot{{\rm{D}}}}{{\rm{O}}_2}$ , and higher O2 Ext. In elderly patients, O2 Ext rather than ḊO2${\dot{{\rm{D}}}}{{\rm{O}}_2}$ could be increased to meet energy consumption demands.

Prolonged enhancement of cytotoxic T lymphocytes in the post-recovery state of severe COVID-19.

We evaluated the peripheral blood immune responses of lymphocytes in severe Coronavirus disease 2019 (COVID-19) patients in different stages of recovery using single-cell mass cytometry. The patients with prolonged hospitalization did not show recovery of B lymphocyte counts and CD4-positive T lymphocyte counts but did show abundant CD8-positive T lymphocytes. CD4 and CD8 T cells expressing high levels of T-bet and Granzyme B were more abundant in post-recovery patients. This study showed that cytotoxic Th1 and CD8 T cells are recruited to the peripheral blood long after recovery from COVID-19.

Efficacy and safety of nintedanib for pulmonary fibrosis in severe pneumonia induced by COVID-19: An interventional study.

OBJECTIVES: One of the most significant features of poor prognosis in COVID-19 is pulmonary fibrosis. Nintedanib is a new antifibrotic agent that interferes with processes of pulmonary fibrosis. This study aimed to investigate the efficacy and safety of nintedanib in COVID-19. METHODS: This was an interventional study in which adult patients with COVID-19 requiring mechanical ventilation were consecutively enrolled. The primary endpoint was 28-day mortality after the initiation of mechanical ventilation. The secondary endpoints were length of mechanical ventilation, volume of lung injury, and the incidence of gastrointestinal adverse events and acute liver failure. RESULTS: Thirty patients with COVID-19 underwent nintedanib therapy. We included 30 patients not receiving nintedanib as the historical control group. There were no significant differences in 28-day mortality between the groups (23.3% vs 20%, P = 0.834). Lengths of mechanical ventilation were significantly shorter in the nintedanib group (P = 0.046). Computed tomography volumetry showed that the percentages of high-attenuation areas were significantly lower in the nintedanib group at liberation from mechanical ventilation (38.7% vs 25.7%, P = 0.027). There were no significant differences in the adverse events. CONCLUSIONS: The administration of nintedanib may offer potential benefits for minimizing lung injury in COVID-19.

Splenic volume on computed tomography scans is associated with mortality in patients with sepsis.

OBJECTIVES: The spleen is a key organ of the immune system. Asplenia has been reported to increase the risk of sepsis from overwhelming post-splenectomy infection. However, there are few reports on the association between splenic volume and mortality in patients with no history of splenectomy. This study focused on splenic volume of patients with sepsis and evaluated the association between splenic volume and mortality. METHODS: We retrospectively investigated 232 patients with sepsis. The splenic volume was calculated by using computed tomography scans obtained on admission. The patients were categorized into tertiles based on their splenic volume, and the relationship between splenic volume and mortality was evaluated. Odds ratio curves based on splenic volume were created to assess the continuous associations between splenic volume and outcome with a logistic regression model. RESULTS: The patients with sepsis were divided into three groups according to the first (73.6cm3) and second (128.7cm3) tertile values of splenic volume. Kaplan-Meier estimation of the probability of the patients' survival followed up to 28 days showed significant differences between the groups (p=0.03). The hazard ratio for 28-day mortality in the first tertile group was 3.46 (95% CI 1.3-10.2; p=0.01) as compared with patients in the third tertile group. Patients with smaller spleens had increased odds ratios for mortality in the logistic regression model. CONCLUSIONS: Splenic volume appeared to be an independent predictor of poor prognosis.