BACKGROUND:Human embryonic stem cels exhibit self-renewal and multi-differentiation potential, and can differentiate into endothelial cels under certaininduction conditions.
OBJECTIVE:To explore induced conditions of the human embryonic stem cels differentiating into endothelial cels and to investigate the effect of vascular endothelial growth factors on theendothelial differentiation of human embryonic stem cels.
METHODS:After resuscitation,passage40 human embryonic stem cel lines H9 weresubjected to suspension culture to prepare embryos, and after 5-day culture,these cels werecultured in attachment medium to differentiate into embryoid bodies,folowed by induction with50 μg/L vascular endothelial growth factors. Passage 2 and 15 embryonic stem cels after induced differentiation weretaken for Dil-Ac-LDL uptake test and immunohistochemical staining, respectively.
RESULTS AND CONCLUSION:After 1-day culture, cord-like or polygonal monolayer cels around embryoid bodies showed bud-like andradialgrowth witharelative rapid speed merging into surrounding colonies; at 2-3 days, the number of suspension cels increased further, but the smal-round cels in the center began to die; at 5 days, embryoid bodies started to passage, and aggregated cels exhibited typical paving stone-like appearance. Moreover, some human embryonic cels after induced differentiation could actively takeupfluorescent labeled LDL,andred fluorescent particlesappeared.Additionaly, passage 15 embryonic stem cels after induced differentiation could express CD31 and FLK-1.These findings suggest that human embryonic stem cels induced by vascular endothelial growth factors can differentiate into endothelial cels.

ObjectiveTo verify the reliability of the mouse model of cerebral cortical microinfarct induced by two-photon microscopy and to explore its pathological changes.MethodsSeventeen male C57BL/6J mice were randomly divided into a microinfarct group (n=11) or a sham operation group (n=6).A thinned cranial window of 3 mm diameter was performed over the cerebral cortex with a high-speed micro-drill until the small blood vessels were clearly observed under a dissecting microscope.Then, a permanent single cortical penetrating arteriole occlusion was induced with a gradually enhanced ultrashort laser irradiation through the thinned cranial window with two-photon microscopy.At 7 days after modeling, the cerebral microinfarct volume was measured with HE staining, and the neuron loss, activation of glial cells and deposition of 3-nitrotyrosine were assessed using immunohistochemistry.ResultsThe target vessels of cerebral cortex in 8 (72.7%) mice were occluded and the microinfarcts formed in the microinfarct group, and the average microinfarct volume was 317.23±20.29 μm3.There were remarkable neuron loss and microglia infiltration in the infarcted core, a large number of reactive astrocytes surrounding the infarcted lesion, and massive deposition of 3-nitrotyrosine in the peri-infarct area.No infarcts were observed in the sham operation group.The deposition of 3-nitrotyrosine in the sham operation group was significantly less than that in the microinfarct group (8.00±1.48 vs.98.38±9.10;t=23.962, P<0.001).Conclusions The mouse model of cerebral cortical microinfarct induced by two-photon microscopy is reliable, and its histopathologic changes are consistent with the pathologic features of cerebral microinfarct.

Objective:To observe the effect of high-flow nasal cannula oxygen therapy (HFNC) in patients with chronic obstructive pulmonary disease (COPD) and mild hypercapnia, and to evaluate the early predictive ability of physiological parameters in these patients.Methods:A retrospective cohort study was conducted based on Medical Information Mart for Intensive Care-Ⅳ (MIMIC-Ⅳ) updated in September 2020 and the data of adult patients with COPD and mild hypercapnia [45 mmHg (1 mmHg = 0.133 kPa) < arterial partial pressure of carbon dioxide (PaCO 2)≤ 60 mmHg] from 2008 to 2019 were collected. These patients were assigned to the HFNC group or non-invasive ventilation (NIV) group according to whether they received HFNC or NIV. Baseline data such as gender, age, body mass index (BMI), simplified acute physiology scoreⅡ (SAPSⅡ), Charlson comorbidity index (CCI) and physiological parameters were collected. A propensity score matching was conducted according to the baseline data of the HFNC group patients. The 48-hour and 28-day intubation rates, 28-day mortality, length of intensive care unit (ICU) stay, the length of hospital stay, and the changes in physiological parameters within 48 hours after treatment were compared between the two groups. The receiver operating characteristic curve (ROC curve) was drawn and the ratio of heart rate over pulse oxygen saturation (HR/SpO 2) and ROX index [SpO 2 / (inhaled oxygen concentration, FiO 2×respiratory rate, RR)] were analyzed to predict the 24-hour and 48-hour intubation rates. Results:A total of 524 520 inpatient records were screened and 153 patients were included, while 37 patients in the HFNC group and 116 patients in NIV group. There were 31 patients in the HFNC group and 84 patients in the NIV group remained after propensity score matching according to the baseline data. There were no significant differences in the baseline data of gender, age, BMI, SAPSⅡ, CCI score, physiological parameters and prognosis data except the length of ICU stay. The length of ICU stay in HFNC group was significant longer than that of the NIV group [days: 4.6 (3.1, 10.0) vs. 3.1 (1.6, 5.8), P < 0.05]. HR and RR at 40- 48 hours were significantly lower than those at 0-8 hours after treatment only in the HFNC group [HR (bpm): 84.1±12.2 vs. 91.1±16.4, RR (times/min): 19.8±4.9 vs. 21.6±4.1, both P < 0.05]. Both in the HFNC group and NIV group the pH increased (7.42±0.08 vs. 7.36±0.05 and 7.41±0.06 vs. 7.36±0.05, both P < 0.05) and PaCO 2 decreased significantly [mmHg: 46.3 (39.5, 51.0) vs. 49.8 (45.5, 54.0) and 46.0 (40.5, 51.5) vs. 49.5 (45.5, 55.3), both P < 0.05]. The HR, PaO 2 were higher in the HFNC group than those in the HFNC group at 40-48 hours after treatment [HR (bpm): 91.1±15.4 vs. 84.1±12.2, PaO 2 (mmHg): 99.5 (86.0, 132.3) vs. 85.8 (76.5, 118.0), both P < 0.05], PaO 2/FiO 2 were lower in the HFNC group than that in the HFNC group at 40-48 hours after treatment [mmHg: 223.8 (216.5, 285.0) vs. 278.0 (212.3, 306.0), P < 0.05]. Both HR/SpO 2 and ROX index at 4 hours after treatment had predictive value for 24-hour and 48-hour intubation in the HFNC group. The areas under ROC curve (AUC) of HR/SpO 2 at 4 hours after treatment in the HFNC group were larger than those of ROX index for predicting 24-hour and 48-hour intubation (24-hour: 0.649 vs. 0.574, 48-hour: 0.692 vs. 0.581, both P < 0.01); the 95% confidence interval (95% CI) of 4 hours HR/SpO 2 and for ROX index predicting 24 hours and 48 hours intubation were 0.497-0.780, 0.567-0.799, 0.450-0.694 and 0.454-0.716, respectively. The high sensitivity of HR/SpO 2 and ROX index in predicting 24-hour and 48-hour intubation were 84.6%, 92.9%, 88.2% and 94.4%, respectively, and the low specificity were 52.3%, 23.7%, 54.7% and 29.6%, respectively. Conclusions:HFNC can be used in COPD patients with mild hypercapnia, but it cannot replace NIV. The accuracy of ROX index at 4 hours after HFNC treatment in predicting intubation in COPD patients with mild hypercapnia is poor.

Lipid Droplets/metabolism* ; Bacteria ; Lipid Metabolism