Objective To evaluate the relationship between ceftazidime-avibactam(CAZ-AVI)blood concentrations and efficacy in critically ill patients and to investigate the factors influencing blood levels.Methods The CAZ-AVI trough concentrations(Cmin)were detected in 29 patients who received CAZ-AVI treatment for at least 48 hours.The clinical materials of the patients were collected together for retrospective analysis.Results The Cmin of ceftazidime(CAZ)and avibactam(AVI)were(50.95±5.17)and(7.52±0.96)mg·L-1 in the effective group and(31.16±7.03)and(5.37±1.32)mg·L-1 in the ineffective group,respectively.The Cmin of CAZ in the effective group was significantly higher than in the ineffective group(P<0.05),and there was no significant difference in AVI Cmin between the two groups(P>0.05).Spearman's correlation analysis showed that CAZ Cmin was positively correlated with clinical efficacy(P<0.05),and no correlation between AVI Cmin and clinical efficacy(P>0.05).The optimal CAZ Cmin threshold was 24.59 mg·L-1.Multiple linear regression analysis showed that age and creatinine clearance was significantly correlated with the Cmin of CAZ,and creatinine clearance was significantly correlated with AVI Cmin(P<0.05).Conclusions The Cmin of CAZ correlates with efficacy,and it may be more beneficial for clinical treatment to keep the concentration of CAZ-AVI always greater than the minimum inhibitory concentration during the dosing interval.The creatinine clearance should be fully considered when optimizing CAZ-AVI dosage in critically ill patients.

Abstract： ObjectiveThe study aims to explore the effects and regulatory roles of glucose transporter 1 （GLUT1） on the proliferation， migration， adhesion， and angiogenesis of human umbilical vein endothelial cells （HUVECs） under ischemia-hypoxic conditions. MethodsIn vitro experiments were conducted to subject HUVECs to an ischemia-hypoxic-mimicking environment （1% O₂， 5% CO₂， 94% N₂）. The biological characteristics of HUVECs under normoxic and ischemia-hypoxic conditions were compared by assessing cell viability， proliferation capacity， and examining the expression changes of GLUT1， HIF-1α， and VEGFA proteins under ischemia-hypoxia using Western blot technology. Further， GLUT1 was overexpressed using plasmid transfection and the proliferation， migration， adhesion， and angiogenic capabilities of HUVECs were evaluated through scratch assays， cell adhesion assays， and tube formation assays. Mitochondrial morphological changes were observed by transmission electron microscopy，and oxygen consumption rate （OCR） was detected by Seahorse metabolic analyzer to evaluate mitochondrial function. ResultsCompared with normoxic conditions， the ischemia-hypoxic environment significantly inhibited the proliferation， cell viability， migration， and adhesion capabilities of HUVECs and impaired their angiogenic potential. The expression levels of GLUT1， HIF-1α and VEGFA proteins were also markedly reduced. However， when GLUT1 expression was upregulated， the migration， adhesion， and angiogenic capabilities of HUVECs were significantly improved， and the protein expression levels of HIF-1α， VEGFA and VEGFR were increased. Transmission electron microscopy revealed that ischemic-hypoxia leads to mitochondrial swelling and matrix damage， while GLUT1 overexpression significantly alleviates mitochondrial morphology abnormalities. OCR results suggest that GLUT1 overexpression may enhance oxidative phosphorylation of endothelial cells in ischemic-hypoxic environments to improve energy metabolism. These results suggest that GLUT1 may influence the function and angiogenic potential of HUVECs by regulating glucose metabolism and energy supply. ConclusionsThis study reveals the significant regulatory role of GLUT1 in the function of HUVECs under ischemia-hypoxic conditions， potentially through modulating cellular energy metabolism and signal transduction pathways， thereby affecting cell proliferation， migration， adhesion， and angiogenesis. These findings provide a new perspective on the role of GLUT1 in cardiovascular diseases and may offer potential targets for the development of new therapeutic strategies.