Microenvironment responsive charge-switchable nanoparticles act on biofilm eradication and virulence inhibition for chronic lung infection treatment.

Chronic pulmonary infection caused by Pseudomonas aeruginosa (P. aeruginosa) is a common lung disease with high mortality, posing severe threats to public health. Highly resistant biofilm and intrinsic resistance make P. aeruginosa hard to eradicate, while powerful virulence system of P. aeruginosa may give rise to the recurrence of infection and eventual failure of antibiotic therapy. To address these issues, infection-microenvironment responsive nanoparticles functioning on biofilm eradication and virulence inhibition were simply prepared by electrostatic complexation between dimethylmaleic anhydride (DA) modified negatively charged coating and epsilon-poly(l-lysine) derived cationic nanoparticles loaded with azithromycin (AZI) (DA-AZI NPs). Charge reversal responsive to acidic condition enabled DA-AZI NPs to successively penetrate through both mucus and biofilms, followed by targeting to P. aeruginosa and permeabilizing its outer/inner membrane. Then in situ released AZI, which was induced by the lipase-triggered NPs dissociation, could easily enter into bacteria to take effects. DA-AZI NPs exhibited enhanced eradication activity against P. aeruginosa biofilms with a decrease of >99.999% of bacterial colonies, as well as remarkable inhibitory effects on the production of virulence factors and bacteria re-adhesion & biofilm re-formation. In a chronic pulmonary infection model, nebulization of DA-AZI NPs into infected mice resulted in prolonged retention and increased accumulation of the NPs in the infected sites of the lungs. Moreover, they significantly reduced the burden of P. aeruginosa, effectively alleviating lung tissue damages and inflammation. Overall, the proposed DA-AZI NPs highlight an innovative strategy for treating chronic pulmonary infection.

Venovenous extracorporeal membrane oxygenation for COVID-19 and influenza H1N1 associated acute respiratory distress syndrome: A comparative cohort study in China.

Background: Venovenous extracorporeal membrane oxygenation (VV-ECMO) has been demonstrated to be effective in treating patients with virus-induced acute respiratory distress syndrome (ARDS). However, whether the management of ECMO is different in treating H1N1 influenza and coronavirus disease 2019 (COVID-19)-associated ARDS patients remains unknown. Methods: This is a retrospective cohort study. We included 12 VV-ECMO-supported COVID-19 patients admitted to The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Eighth People's Hospital, and Wuhan Union Hospital West Campus between January 23 and March 31, 2020. We retrospectively included VV-ECMO-supported patients with COVID-19 and H1N1 influenza-associated ARDS. Clinical characteristics, respiratory mechanics including plateau pressure, driving pressure, mechanical power, ventilatory ratio (VR) and lung compliance, and outcomes were compared. Results: Data from 25 patients with COVID-19 (n=12) and H1N1 (n=13) associated ARDS who had received ECMO support were analyzed. COVID-19 patients were older than H1N1 influenza patients (P=0.004). The partial pressure of arterial carbon dioxide (PaCO2) and VR before ECMO initiation were significantly higher in COVID-19 patients than in H1N1 influenza patients (P <0.001 and P=0.004, respectively). COVID-19 patients showed increased plateau and driving pressure compared with H1N1 subjects (P=0.013 and P=0.018, respectively). Patients with COVID-19 remained longer on ECMO support than did H1N1 influenza patients (P=0.015). COVID-19 patients who required ECMO support also had fewer intensive care unit and ventilator-free days than H1N1. Conclusions: Compared with H1N1 influenza patients, COVID-19 patients were older and presented with increased PaCO2 and VR values before ECMO initiation. The differences between ARDS patients with COVID-19 and influenza on VV-ECMO detailed herein could be helpful for obtaining a better understanding of COVID-19 and for better clinical management.

Independent risk factors of hypoxemia in patients after surgery with acute type A aortic dissection.

BACKGROUND: This study aimed to investigate independent risk factors of postoperative hypoxemia in patients with acute type A aortic dissection (ATAAD). METHODS: A single-center retrospective study was conducted with enrolled 75 ATAAD patients following surgery, which were stratified into three groups on the basis of the postoperative PaO2/FiO2 ratio: severe hypoxemia group (PaO2/FiO2 ratio ≤100 mmHg); moderate hypoxemia group (100 mmHg < PaO2/FiO2 ratio ≤200 mmHg); and non-hypoxemia group (PaO2/FiO2 ratio >200 mmHg). The patient's demography, perioperative laboratory results, operative details, clinical outcomes were collected and analyzed. Univariable and multivariable analyses were performed and logistic regression model was established. RESULTS: The incidence of postoperative severe hypoxemia and hypoxemia was 32% and 52%, respectively. Among the three groups, severe hypoxemia group exhibited a high significance of body mass index (BMI) and preoperative white blood cell (WBC) and main distribution of hypertension; meanwhile, Marfan syndrome was mainly distributed in non-hypoxemia group. On intensive care unit (ICU) admission, severe hypoxemia group exhibited a high significance of Acute Physiology and Chronic Health Evaluation (APACHE II) score of postoperative patients, and more patients would present shock. Moreover, severe hypoxemia group patients had a higher incidence of postoperative acute kidney injury (AKI) and usage of renal replacement therapy, longer length of stay (LOS) of ICU, and shorter 28 days ventilator-free days (VFDs). CONCLUSIONS: The incidence of postoperative hypoxemia was high in ATAAD patients owing to comprehensive high-risk factors. Besides, postoperative complications negatively impacted their clinical outcomes.

A pH-Sensitive Polymeric Micellar System Based on Chitosan Derivative for Efficient Delivery of Paclitaxel.

In this study, an amphiphilic conjugate based on mPEG and cholesterol-modified chitosan with hydrazone bonds in the molecules (mPEG-CS-Hz-CH) was successfully synthesized. Using the polymer as the carrier, the paclitaxel (PTX)-loaded mPEG-CS-Hz-CH micelles were prepared by an ultrasonic probe method. The mean particle size and zeta potential of the optimized PTX-loaded micelles were 146 ± 4 nm and +21.7 ± 0.7 mV, respectively. An in vitro drug release study indicated that the PTX-loaded mPEG-CS-Hz-CH micelles were stable under normal physiological conditions (pH 7.4), whereas rapid drug release was observed in the simulated tumor intracellular microenvironment (pH 5.0). An in vitro cytotoxicity study demonstrated the non-toxicity of the polymer itself, and the PTX-loaded micelles exhibited superior cytotoxicity and significant selectivity on tumor cells. An in vivo antitumor efficacy study further confirmed that the PTX-loaded micelles could improve the therapeutic efficacy of PTX and reduce the side effects. All these results suggested that the mPEG-CS-Hz-CH micelles might be promising pH-sensitive nanocarriers for PTX delivery.

Conversion ratio of tacrolimus switching from intravenous infusion to oral administration after lung transplantation.

BACKGROUND: To investigate the conversion ratio of tacrolimus switching from intravenous infusion to oral administration in patients after lung transplantation. METHODS: We retrospectively recruited patients received lung transplantation in the First Affiliated Hospital of Guangzhou Medical Hospital from January 2015 to June 2019. The blood concentration of tacrolimus administrated through intravenous infusion and oral administration were collected. The blood concentration, concentration/dose ratio (C/D), and (C/Dpo)/(C/Div) ratio were analyzed to explore the conversion ratio of tacrolimus switching from intravenous infusion to oral administration, as combined medication of tacrolimus and caspofungin were used. RESULTS: The concentration of intravenously administered tacrolimus was significantly higher than that of oral administration; the C/D ratio of intravenously administrated tacrolimus (C/Div) was significantly higher than that of the oral administration (C/Dpo). There was a significant correlation between C/Dpo and C/Div (R2 =0.774, P<0.001). The conversion ratio of tacrolimus from intravenous administration to oral administration was 1:7.4, as combined medication of tacrolimus and caspofungin were used. CONCLUSIONS: The conversion ratio of tacrolimus switching from intravenous to oral administration is 1:7.4 in the combination treatment of tacrolimus and caspofungin after lung transplantation.

Effects of Xuebijing injection on microcirculation in septic shock.

BACKGROUND: This study was conducted to investigate whether Xuebijing injection can rectify the dysfunction of microcirculation in septic shock and assessed the microcirculatory parameters directly via orthogonal polarization spectral and software AVA 3.0. MATERIAL AND METHODS: Anesthetized and mechanically ventilated beagle dogs were modeled for septic shock via lipopolysaccharide (LPS) intravenous injection. They were divided randomly into four groups, control group accepted operation only for jejunostomy and cystostomy; LPS group accepted operation and LPS intravenous injection; saline group accepted operation, LPS intravenous injection, and saline resuscitation; XBJ group accepted operation, LPS intravenous injection, saline resuscitation, and Xuebijing injection infusion. The MAP was recorded via right femoral artery catheterization, at the same time, the blood gas analysis was taken via that pathway at the set time points. ScvO2 was obtained via right jugular vein catheterization at the related time points. Microcirculatory parameters were recorded by orthogonal polarization spectral via the jejunum stoma, and the microcirculation image was analyzed via the software AVA 3.0 later. RESULTS: Xuebijing injection improved microcirculation of the jejunum villus in canine model of septic shock induced by endotoxin, especially for the proportion of perfused vessels. CONCLUSIONS: Based on the adequate fluid resuscitation, Xuebijing injection plays a helpful role of improving microcirculation in septic shock.

Heparin inhibits lipopolysaccharide-induced inflammation via inducing caveolin-1 and activating the p38/mitogen-activated protein kinase pathway in murine peritoneal macrophages.

Heparin is a soluble glycosaminoglycan largely used as an anti-coagulant drug and with well known anti­inflammatory effects. However, heparin is currently not used as an anti­inflammatory agent in the clinic due to a risk of bleeding as well as its complex mechanism of action. The underlying mechanism of the anti­inflammatory action of heparin and its effector targets have remained to be fully elucidated. The present study confirmed the anti­inflammatory effects of heparin in lipopolysaccharide (LPS)­induced murine peritoneal macrophages through decreasing the levels of the inflammatory cytokines tumor necrosis factor alpha (TNF­α), interleukin 6 (IL­6), IL­8 and IL­1ß. Caveolin­1 participated in the anti­inflammatory process and it was able to be induced by heparin. Transfection of small interfering RNA of caveolin­1 into murine peritoneal macrophages attenuated the anti­inflammatory effects of heparin. Furthermore, following caveolin­1 silencing, the p38/mitogen­activated protein kinase (MAPK) pathway was still able to be activated by heparin, while the extracellular signal­regulated kinase and c­Jun N­terminal kinase pathways were inhibited. In conclusion, these results suggested that heparin inhibits LPS­induced inflammation via inducing caveolin­1 and activating the p38/MAPK pathway in murine peritoneal macrophages. Revealing the anti­inflammatory mechanisms of heparin will aid in its development for clinical treatment in the future.

Azurocidin-induced inhibition of oxygen metabolism in mitochondria is antagonized by heparin.

Heparin is a potent blood anticoagulant that has been demonstrated to attenuate inflammatory responses in sepsis. Sepsis is considered to be a microcirculation-mitochondrial distress syndrome. Azurocidin (AZU), a protein with strong heparin-binding potential that induces inflammatory responses and apoptosis, has been shown to increase the permeability of endothelial cells and induce the prognosis of sepsis. However, the function of AZU in mitochondrial oxygen metabolism has yet to be reported. The aim of the present study was to investigate whether heparin exhibits an antagonistic effect on AZU-induced mitochondrial dysfunction in human umbilical vein endothelial cells (HUVECs) and to further investigate the possible underlying mechanisms. HUVECs were randomly assigned into blank control, AZU, heparin plus AZU and heparin groups. The blank control group were incubated with phosphate-buffered saline for 12 h, while the AZU group were incubated with 1 µg/ml AZU for 12 h. The heparin plus AZU group were incubated with 100 µg/ml heparin for 2 h, followed by the addition of 1 µg/ml AZU and incubation for 12 h. The heparin group were incubated with 100 µg/ml heparin for 12 h. Flow cytometry was used to determine the mitochondrial membrane potential, while electron microscopy was used to determine the mitochondrial morphology. Western blotting and quantitative polymerase chain reaction were used to determine the protein and mRNA expression levels of Cox II in the mitochondria, respectively. Western blotting was also used to evaluate the concentration of AZU in cytoplasm, along with immunofluorescence analysis. AZU was revealed to decrease the mitochondrial membrane potential, reduce cytochrome c oxidase subunit II expression and destroy the morphology of the mitochondria. Heparin exhibited an antagonistic function on these processes and inhibited the endocytosis of AZU by HUVECs. In conclusion, the results indicated that AZU inhibited the oxygen metabolic function in mitochondria, and this function was effectively antagonized by heparin via the inhibition of AZU endocytosis by HUVECs. Therefore, heparin may be a potential therapeutic agent for treating mitochondrial dysfunction in the future.

Tetramethylpyrazine attenuates TNF-α-induced iNOS expression in human endothelial cells: Involvement of Syk-mediated activation of PI3K-IKK-IκB signaling pathways.

Endothelial cells produce nitric oxide (NO) by activation of constitutive nitric oxide synthase (NOS) and transcription of inducible NO synthase (iNOS). We explored the effect of tetramethylpyrazine (TMP), a compound derived from chuanxiong, on tumor necrosis factor (TNF)-α-induced iNOS in human umbilical vein endothelial cells (HUVECs) and explored the signal pathways involved by using RT-PCR and Western blot. TMP suppressed TNF-α-induced expression of iNOS by inhibiting IκB kinase (IKK) phosphorylation, IκB degradation and nuclear factor κB (NF-κB) nuclear translocation, which were required for NO gene transcription. Exposure to wortmannin abrogated IKK/IκB/NF-κB-mediated iNOS expression, suggesting activation of such a signal pathway might be phosphoinositide-3-kinase (PI3K) dependent. Spleen tyrosine kinase (Syk) inhibitor piceatannol significantly inhibited NO production. Furthermore, piceatannol obviously suppressed TNF-α-induced IκB phosphorylation and the downstream NF-κB activation, suggesting that Syk is an upstream key regulator in the activation of PI3K/IKK/IκB-mediated signaling. TMP significantly inhibited TNF-α-induced phosphorylation of Syk and PI3K. Our data indicate that TMP might repress iNOS expression, at least in part, through its inhibitory effect of Syk-mediated PI3K phosphorylation in TNF-α-stimulated HUVECs.