Early Warning Factors of Death in COVID-19 Patients.

The infectious coronavirus disease 2019 (COVID-19) has spread all over the world and been persistently evolving so far. The number of deaths in the whole world has been rising rapidly. However, the early warning factors for mortality have not been well ascertained. In this retrospective, single-centre cohort study, we included some adult inpatients (≥18 years old) with laboratory-confirmed COVID-19 from Renmin Hospital of Wuhan University who had been discharged or had died by Apr. 8, 2020. Demographic, clinical and laboratory data at admission were extracted from electronic medical records and compared between survivors and non-survivors. We used univariable analysis, Cox proportional hazard model analysis and receiver operating characteristic (ROC) curve to explore the early warning factors associated with in-hospital death. A total of 159 patients were included in this study, of whom 86 were discharged and 73 died in hospital. Hypertension (52.1% vs. 29.1%, P=0.003) and coronary heart disease (28.8% vs. 12.8%, P=0.012) were more frequent among non-survived patients than among survived patients. The proportions of patients with dyspnoea (67.1% vs. 25.6%, P<0.001), chest distress (58.9% vs. 26.7%, P<0.001) and fatigue (64.4% vs. 25.6%, P<0.001) were significantly higher in the non-survived group than in the survived group. Regression analysis with the Cox proportional hazards mode revealed that increasing odds of in-hospital death were associated with higher IL-6 (odds ratio 10.87, 95% CI 1.41-83.59; P=0.022), lactate (3.59, 1.71-7.54; P=0.001), older age (1.86, 1.03-3.38; P=0.041) and lower lymphopenia (5.44, 2.71-10.93; P<0.001) at admission. The areas under the ROC curve (AUCs) of IL-6, lymphocyte, age and lactate were 0.933, 0.928, 0.786 and 0.753 respectively. The AUC of IL-6 was significantly higher than that of age (z=3.332, P=0.0009) and lactate (z=4.441, P<0.0001) for outcome prediction. There was no significant difference between the AUCs of IL-6 and lymphocyte for outcome prediction (z=0.372, P=0.7101). It was concluded that the potential risk factors of higher IL-6, lactate, older age and lower lymphopenia at admission could help clinicians to identify patients with poor prognosis at an early stage.

Mechanism of Cxc Chemokine Ligand 5 (CXCL5)/Cxc Chemokine Receptor 2 (CXCR2) Bio-Axis in Mice with Acute Respiratory Distress Syndrome.

BACKGROUND Acute respiratory distress syndrome (ARDS) is a common acute and severe disease in clinic. Recent studies indicated that Cxc chemokine ligand 5 (CXCL5), an inflammatory chemokine, was associated with tumorigenesis. The present study investigated the role of the CXCL5/Cxc chemokine receptor 2 (CXCR2) bio-axis in ARDS, and explored the underlying molecular mechanism. MATERIAL AND METHODS The pathological morphology of lung tissue and degree of pulmonary edema were assessed by hematoxylin-eosin staining and pulmonary edema score, respectively. Real-time PCR and Western blot analysis were performed to detect the expression levels of CXCL5, CXCR2, Matrix metalloproteinases 2 (MMP2), and Matrix metalloproteinases 9 (MMP9) in lung tissues. Enzyme-linked immunosorbent assay (ELISA) was performed to determine the expression levels of CXCL5 and inflammatory factors (IL-1ß, IL-6, TNF-alpha, and IL-10) in serum. RESULTS The results demonstrated that diffuse alveolar damage and pulmonary edema appeared in lipopolysaccharide (LPS)-induced ARDS and were positively correlated with the severity of ARDS. In addition, CXCL5 and its receptor CXCR2 were overexpressed by upregulation of MMP2 and MMP9 in lung tissues of ARDS. In addition, CXCL5 neutralizing antibody effectively alleviated inflammatory response, diffuse alveolar damage, and pulmonary edema, and decreased the expression levels of MMP2 and MMP9 compared to LPS-induced ARDS. CONCLUSIONS We found that CXCL5/CXCR2 accelerated the progression of ARDS, partly by upregulation of MMP2 and MMP9 in lung tissues with the release of inflammatory factors.

Lipopolysaccharide Stimulates Surfactant Protein-A in Human Renal Epithelial HK-2 Cells through Upregulating Toll-like Receptor 4 Dependent MEK1/2-ERK1/2-NF-κB Pathway.

BACKGROUND: Surfactant protein-A (SP-A) contributes to the regulation of sepsis-induced acute kidney injury. In a previous study, we demonstrated that the expression of SP-A in the human renal tubular epithelial (HK-2) cells can be stimulated by lipopolysaccharide (LPS). The present study evaluated the possible signal-transducing mechanisms of LPS-induced SP-A biosynthesis in the HK-2 cells. METHODS: Tetrazolium salt colorimetry (MTT) assay was used to detect cell viability of HK-2 cells after LPS stimulation on different time points. HK-2 cells were stimulated with 100 ng/ml of LPS for different durations to determine the effects of LPS on SP-A and toll-like receptor 4 (TLR4) messenger RNA (mRNA) expression, as well as phosphorylation of mitogen-activated/extracellular signal-regulated kinase (MEK) 1, extracellular signal-regulated kinase 1/2 (ERK1/2), p38 mitogen-activated protein kinase (p38MAPK), and nuclear factor-kappa B (NF-κB) inhibitor-alpha (IkB-α). Then, HK-2 cells were pretreated with CLI-095, a TLR4 inhibitor, to analyze mRNA and protein levels of SP-A and TLR4 and expression of NF-κB in the cytoplasm and nucleus of HK-2 before LPS exposure. RESULTS: HK-2 cells exposed to 100 ng/ml of LPS for 1, 6, and 24 h did not affect cell viability which showed no toxic effect of 100 ng/ml LPS on cells (P = 0.16); however, the biosynthesis of SP-A mRNA and protein in HK-2 cells was significantly increased (P = 0.02). As to the mechanism, LPS enhanced transmembrane receptor TLR4 protein expression. Sequentially, LPS time dependently augmented phosphorylation of MEK1, ERK1/2, and p38MAPK. In addition, levels of phosphorylated IκB-α and nuclear NF-κB were augmented with LPS exposure for 2 h. LPS-induced SP-A and TLR4 mRNA as well as NF-κB expression were significantly inhibited by pretreatment with CLI-095. CONCLUSIONS: The present study exhibited that LPS can increase SP-A synthesis in human renal epithelial cells through sequentially activating the TLR4-related MEK1-ERK1/2-NF-κB-dependent pathway.

MiR-28 inhibits cardiomyocyte survival through suppressing PDK1/Akt/mTOR signaling.

MicroRNAs play critical roles in regulating cell survival under multiple pathological conditions of heart diseases. Oxidative stress-induced apoptosis contributes greatly to heart ischemia-reperfusion injury. Herein, we describe a novel regulatory role of miR-28 on the survival of cardiomyocytes. We show that miR-28 was upregulated in cardiomyocytes treated with hydrogen peroxide (H2O2). MiR-28 gain of function sensitized cell apoptosis, whereas miR-28 loss of function partially rescued cell apoptosis induced by H2O2. Importantly, we observed a significant reduction in Akt/mammalian target of rapamycin (mTOR) signaling activity after miR-28 treatment. Luciferase activity assay and western blot analysis both revealed that, phosphoinositide-dependent kinase-1 (PDK1), which is critical for Akt activation, was directly and negatively modulated by miR-28. Our results therefore indicate that miR-28 regulates oxidative stress-induced cell apoptosis in heart muscle cells, which possibly involves a PDK1/Akt/mTOR-dependent mechanism. MIR-28 could serve as a critical therapeutic target to diminish oxidative stress-induced cell death in the heart.

Protective effect of propofol and its relation to postoperation recovery in children undergoing cardiac surgery with cardiopulmonary bypass.

The aim of this study was to investigate the effect of propofol and its relation to postoperation recovery in children undergoing cardiac surgery with cardiopulmonary bypass (CPB). Twenty ASA class I-II children with congenital heart disease undergoing cardiac surgery were randomly allocated to a propofol group (n = 10) or a control group (n = 10). Blood samples were collected at five time points: before operation (T (0)), before the start of CPB (T (1)), 25 min after the aorta was cross-clamped (T (2)), 30 min after release of the aortic cross-clamp (T (3)), and 2 h after the cessation of CPB (T (4)). The myocardial samples were collected at the time of incubation into the right atrium before CPB and at 30 min after reperfusion. After CPB, propofol significantly suppressed the increase of the serum lactate dehydrogenase (LDH), creatine phosphokinase (CK), and interleukin-6 (IL-6) levels and the decrease of the serum superoxide dismutase (SOD) level. In addition, propofol inhibited the increase of myocardial nuclear factor-κB (NF-κB) expression and inflammatory cells infiltration after CPB. Furthermore, propofol significantly shortened the tracheal extubation time. In conclusion, propofol exerts a protective effect and improves postoperation recovery through its antioxidant and anti-inflammatory actions in children undergoing cardiac surgery with CPB.

Comparison of the effects of propofol and midazolam on inflammation and oxidase stress in children with congenital heart disease undergoing cardiac surgery.

PURPOSE: To investigate and compare the effects of propofol and midazolam on inflammation and oxidase stress in children with congenital heart disease undergoing cardiac surgery. MATERIALS AND METHODS: Thirty-two ASA class I-II children with congenital heart disease undergoing cardiac surgery were randomly divided into two groups: propofol combined with low dose fentanyl (PF group, n = 16) and midazolam combined with low dose fentanyl (MF group, n = 16). Tracheal extubation time and length of Intensive Care Unit (ICU) stay were recorded. Blood samples were taken before operation (T0), at 2 h after release of the aorta cross-clamp (T3) and at 24 h after operation (T4) to measure interleukin 6 (IL-6), IL-8, superoxide dismutase (SOD) and malondialdehyde (MDA) levels. Myocardium samples were collected at 10-20 min after aorta cross-clamp (T1) and at 10-20 min after the release of the aorta cross-clamp (T2) to detect heme oxygenase-1 (HO-1) expression. RESULTS: Tracheal extubation time and length of ICU stay in PF group were significantly shorter than those of the MF group (p < 0.05, respectively). After cardiopulmonary bypass, IL-6, IL-8 and MDA levels were significantly increased, and the SOD level was significantly reduced in both two groups, but PF group exhibited lower IL-6, IL-8 and MDA levels and higher SOD levels than the MF group (p < 0.05, respectively). The HO-1 expression in the PF group was significantly higher than that in MF group at the corresponding time points (p < 0.05, respectively). CONCLUSION: Propofol is superior to midazolam in reducing inflammation and oxidase stress and in improving post-operation recovery in children with congenital heart disease undergoing cardiac surgery.

Effects of ketamine on the balance of ions Ca2+, Mg2+, Cu2+ and Zn2+ in the ischemia-reperfusion affected spinal cord tissues in rabbits.

To test the effects of ketamine on metal ion balance in the spinal cord tissues after ischemic reperfusion (I/R), 24 white adult Japanese rabbits were randomly assigned to sham operation group, I/R group or ketamine-treated I/R group. Spinal cord injuries in I/R group and ketamine-treated I/R group were induced by aortic occlusions. Rabbits in ketamine-treated I/R group were intravenously infused 10 mg/kg ketamine twice: once at 10 min before aortic clamping and once at the onset of reperfusion. Post-operative neurological functions and concentrations of ions Ca2+, Mg2+, Cu2+ and Zn2+ in the spinal cord were assessed. Compared with the sham operation group, rabbits in the I/R group showed significantly worsened neurological functions as scored with the modified Tarlov criteria and altered concentrations of ions Ca2+, Mg2+, Cu2+ and Zn2+. These unfavorable changes were significantly reversed in the ketamine-treated I/R group, suggesting that the potent protective effects of ketamine against the I/R-induced spinal cord injuries may be due to its ability to maintain ion balance in the I/R affected tissues.

Protective effect of ketamine on ischemic spinal cord injury in rabbits.

We tested our hypothesis that a commonly used anesthetic, ketamine, may offer benefits to protect animals from spinal cord injury, using the ischemia/reperfusion (I/R) injury rabbit model in a randomized controlled study. We used 24 white adult Japanese rabbits from the animal facility at the Medical College of Wuhan University. The rabbits were randomly assigned to one of three groups, eight rabbits per group: group I, sham-operation group; group II, I/R group; group III, I/R with ketamine treatment group. Spinal cord ischemia was induced by infrarenal aortic cross-clamp for 45 min in group II and group III, and ketamine was intravenously infused at 10 mg/kg in 15 mL 0.9% sodium chloride at a speed of 1.5 mL/min to animals in group III, once at 10 min before aortic clamping and once at the onset of reperfusion. Postoperative neurological function, electromyography of rear limbs, histopathology, malondialdehyde (MDA) levels, and superoxide dismutase (SOD) activity in the spinal cord were assessed in all animals. Compared with the control group I, group II showed significant I/R injury-induced changes in neurological function scores, histopathology, and electromyography (p < 0.01). However, group III with ketamine treatment significantly reversed the changes in all these parameters (p < 0.01). At the same time, the I/R-induced increase in MDA content observed in group II was also significantly reduced in group III (p < 0.01), and the I/R-induced decreases in SOD activity were also significantly prevented in group III (p < 0.01). After ketamine treatment, all parameters examined in group III were not significantly different from those obtained in group I. Ketamine showed potent protective effects against spinal cord I/R injury in the rabbit model and protected loss of antioxidant activity in spinal cord tissues.

[Cardioprotective effects of propofol and midazolam in children with congenital heart diseases undergoing open heart surgery].

OBJECTIVE: To observe the cardioprotective effects of propofol and midazolam in children with congenital heart diseases undergoing open heart surgery. METHODS: Thirty-two children with cyanotic congenital heart diseases of ASA classes I - II were randomly divided into 2 equal groups: propofol combined with low dose fentanyl group (Group PF) and midazolam combined with low dose fentanyl group (Group MF). The changes of hemodynaics, ECG, SpO2, nasopharyngeal and rectal temperatures were monitored continuously. The time of tracheal extubation and ICU staying time were recorded. Venous blood samples were collected when the venous channel was opened (T(0)), 2 h after declamping of the aorta (T(4)), and 24 h after operation (T(5)) to detect the plasma cardiac troponin I (cTnI). Myocardium samples were collected 10 - 20 min after aorta cross-clamp (T(2)), and 10 - 20 min after declamping of the aorta (T(3)) to undergo immunohistochemistry to observe the expression of heme oxygenase-1 (HO-1). RESULTS: The tracheal time of Group GF was 14.17 h, significantly shorter than that of Group MF (23.65 h, P < 0.05), and the ICU staying time of Group GF was 30.17 h, significantly shorter than that of Group MF (49.47 h, P < 0.05). The plasma cTnI level at T(4) of Group GF was 97 ng/ml +/- 33 ng/ml, significantly higher than those at T(0) (0.17 ng/ml +/- 0.10 ng/ml, P < 0.01) and T(5) (23 ng/ml +/- 13 ng/ml, P < 0.01). The plasma cTnI level at T(4) of Group MF was138 ng/ml +/- 56 ng/ml, significantly higher than those at T(0) (0.62 ng/ml +/- 0.96 ng/ml, P < 0.01) and T(5) (24 ng/ml +/- 6 ng/ml, P < 0.01). And the plasma cTnI levels at T(5) of these 2 groups were both significantly higher than those at T(0) (both P < 0.01), however, there was no significant difference in the plasma cTnI level at any time point between these 2 groups. The grey values of HO-1 in cardiac muscle cells at T(2) of Groups GF and MF were 182.2 +/- 0.8 and 193.5 +/- 1.4, both significantly higher than those at T(3) (125.6 +/- 2.1 and 145.5 +/- 7.4 respectively, both P < 0.01), and the grey values of HO-1 in cardiac muscle cells at T(2) and T(3) of Group MF were both significantly higher than those of Group GF (both P < 0.05). CONCLUSION: Both propofol and midazolam have protective effects for the children with congenital heart diseases undergoing open heart surgery, and propofol is superior to midazolam in the cardioprotection.

[Protective effect of ferulic acid on neuronal apoptosis of spinal cord subsequent to aortic blood cross-clamping in rabbits].

OBJECTIVE: To investigate the protective effect of ferulic acid on neuronal apoptosis of the spinal cord after aortic blood cross-clamping and its mechanism in rabbits. METHODS: Twenty-four rabbits were randomly divided into sham operation group, ischemia/reperfusion (I/R) injury group and ferulic acid group. Spinal cord I/R injury model was replicated by clamping blood of the infrarenal aorta for 40 minutes followed reperfusion for 7 days. Ferulic acid 50 mg/kg was injected 15 minutes before aortic clamping in ferulic acid group. The aorta was not clamped in sham operation group. Contents of malondialdehyde (MDA) and superoxide dismutase (SOD) in plasma were assayed at 10 minutes before clamping (C-10), before removal of occlusion (C40), at 60 minutes (R60) and on the 7 th day (R7d) after reperfusion. Apoptosis of neurones of spinal cord and the expressions of Bax and Bcl-2 protein were assayed by immunohistochemical technique. Neurologic function score of hind limb was observed after operation. RESULTS: (1)The activity of MDA after I/R in I/R injury group was increased significantly compared with those before clamping and those in sham operation group (P<0.05 or P<0.01). The activity of MDA in ferulic acid group was significantly higher than that at C-10 (P<0.05), while significantly lower than those in I/R injury group at any time point (P<0.05 or P<0.01), but showed no significant difference compared with sham operation group. Changes in SOD activities were opposite to that of MDA. (2)The expression of Bax protein in I/R injury group was increased significantly (P<0.05), but the expression of Bcl-2 protein was decreased significantly compared with that in sham operation group (P<0.01). In ferulic acid group, the expression of Bax protein was significantly lower than that in I/R injury group and higher than that in sham operation group (P<0.01 and P<0.05), and the expression of Bcl-2 protein was higher than those in I/R injury group and sham operation group (both P<0.01). (3)The index of neuronal apoptosis in I/R injury group was significantly higher than that in sham operation group (P<0.01), and that in ferulic acid group was much lower than that in I/R injury group, but higher than sham operation group (P<0.01 and P<0.05). (4)The degree of paralysis in ferulic acid group was significantly lower than that in I/R injury group, and a higher neurologic score was observed (both P<0.01). CONCLUSION: Ferulic acid can reduce the spinal cord neuronal apoptosis as a result of aortic occlusion in rabbits. The possible mechanism is that it decreases protein expression of Bax, increases that of Bcl-2 and enhances antioxidation.

Effect of repetitive ischemic preconditioning on spinal cord ischemia in a rabbit model.

A completely randomized controlled study based on a rabbit model was designed to study the effect of repetitive ischemic preconditioning (IPC) on a spinal cord ischemic reperfusion injury. Twenty four white adult Japanese rabbits were randomly assigned to one of the 3 groups (n = 8 per group): Group I: sham-operation group, Group II: ischemic reperfusion group, and, Group III: IPC group. Spinal cord ischemia was induced by infra-renal aortic cross-clamp for 45 min in Group II. Before 45 min ischemia, the rabbits in Group III underwent four cycles of IPC (5 min of ischemia followed by 5 min of reperfusion). Post-operative neurological function, electromyography (EMG) of rear limbs, and spinal cord histopathological changes were measured. The concentrations of calcium, magnesium, copper, and zinc in spinal cord were measured in the 7th day. The neurological function and histopathological changes in Group II were significantly different from those in Group I or Group III (P < 0.05 or 0.01). There was a more significant change of EMG in Group II than that in Group III (P < 0.05). The concentrations of calcium and copper in Group II were significantly higher (P < 0.05 or 0.01), but magnesium and zinc were significantly lower (P < 0.05) than those in Group I. Calcium and copper in Group II were significantly higher (P < 0.05), but zinc was significantly lower (P < 0.01) than those in Group III. In conclusion, repetitive IPC can protect rabbit spinal cord from ischemic reperfusion injury in a timely manner, which is associated with corrections of imbalance of calcium, magnesium, copper, and zinc in the ischemic region.

Propofol dose-dependently reduces tumor necrosis factor-alpha-Induced human umbilical vein endothelial cell apoptosis: effects on Bcl-2 and Bax expression and nitric oxide generation.

We investigated whether propofol can inhibit tumor necrosis factor (TNF)-alpha-induced apoptosis in cultured human umbilical vein endothelial cells (HUVECs). Isolated HUVECs were cultured in Dulbecco's modified Eagle medium supplemented with 20% bovine calf serum. HUVECs in untreated and propofol control groups were cultured at 37 degrees C for 24.5 h. HUVECs in the TNF treatment groups were initially cultured for 30 min in the presence of TNF or various concentrations of propofol, respectively, which were then cultured for 24 h with the addition of TNF at 40 ng/mL in the medium. Apoptosis was detected using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) and confirmed by electron microscopy. The antiapoptotic Bcl-2 and proapoptotic Bax protein expressions were measured by immunocytochemical analysis. TNF stimulation resulted in a reduced Bcl-2/Bax ratio and increased apoptotic index (AI: percentage of apoptotic cells) in HUVECs. Propofol, at concentrations >/=12 muM, significantly (P < 0.001) and dose-dependently attenuated TNF-induced increase in AI and decrease in Bcl-2/Bax ratio. This was accompanied by increases in nitric oxide production. There is an inverse correlation between the ratio of Bcl-2/Bax expression and AI (P = 0.0009). These results suggest that propofol, at clinical relevant concentrations, can reduce TNF-induced HUVEC apoptosis.