One-Lung Ventilation and Acute Lung Injury

Syringic acid attenuates acute lung injury by modulating macrophage polarization in LPS-induced mice

BACKGROUND

Acute lung injury (ALI) is a continuum of lung changes caused by multiple lung injuries, characterized by a syndrome of uncontrolled systemic inflammation that often leads to significant morbidity and death. Anti-inflammatory is one of its treatment methods, but there is no safe and available drug therapy. Syringic acid (SA) is a natural organic compound commonly found in a variety of plants, especially in certain woody plants and fruits. In modern pharmacological studies, SA has anti-inflammatory effects and therefore may be a potentially safe and available compound for the treatment of acute lung injury.

PURPOSE

This study attempts to reveal the protective mechanism of SA against ALI by affecting the polarization of macrophages and the activation of NF-κB signaling pathway. Trying to find a safer and more effective drug therapy for clinical use.

METHODS

We constructed the ALI model using C57BL/6 mice by intratracheal instillation of LPS (10 mg/kg). Histological analysis was performed with hematoxylin and eosin (H&E). The wet-dry ratio of the whole lung was measured to evaluate pulmonary edema. The effect of SA on macrophage M1-type was detected by flow cytometry. BCA protein quantification method was used to determine the total protein concentration in bronchoalveolar lavage fluid (BALF). The levels of Interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α in BALF were determined by the ELISA kits, and RT-qPCR was used to detect the expression levels of IL-6, IL-1β and TNF-α mRNA of lung tissue. Western blot was used to detect the expression levels of iNOS and COX-2 and the phosphorylation of p65 and IκBα in the NF-κB pathway in lung tissue. In vitro experiments were conducted with RAW267.4 cell inflammation model induced by 100 ng/ml LPS and A549 cell inflammation model induced by 10 μg/ml LPS. The effects of SA on M1-type and M2-type macrophages of RAW267.4 macrophages induced by LPS were detected by flow cytometry. The toxicity of compound SA to A549 cells was detected by MTT method which to determine the safe dose of SA. The expressions of COX-2 and the phosphorylation of p65 and IκBα protein in NF-κB pathway were detected by Western blot.

RESULTS

We found that the pre-treatment of SA significantly reduced the degree of lung injury, and the infiltration of neutrophils in the lung interstitium and alveolar space of the lung. The formation of transparent membrane in lung tissue and thickening of alveolar septum were significantly reduced compared with the model group, and the wet-dry ratio of the lung was also reduced. ELISA and RT-qPCR results showed that SA could significantly inhibit the production of IL-6, IL-1β, TNF-α. At the same time, SA could significantly inhibit the expression of iNOS and COX-2 proteins, and could inhibit the phosphorylation of p65 and IκBα proteins. in a dose-dependent manner. In vitro experiments, we found that flow cytometry showed that SA could significantly inhibit the polarization of macrophages from M0 type macrophages to M1-type macrophages, while SA could promote the polarization of M1-type macrophages to M2-type macrophages. The results of MTT assay showed that SA had no obvious cytotoxicity to A549 cells when the concentration was not higher than 80 μM, while LPS could promote the proliferation of A549 cells. In the study of anti-inflammatory effect, SA can significantly inhibit the expression of COX-2 and the phosphorylation of p65 and IκBα proteins in LPS-induced A549 cells.

CONCLUSION

SA has possessed a crucial anti-ALI role in LPS-induced mice. The mechanism was elucidated, suggesting that the inhibition of macrophage polarization to M1-type and the promotion of macrophage polarization to M2-type, as well as the inhibition of NF-κB pathway by SA may be the reasons for its anti-ALI. This finding provides important molecular evidence for the further application of SA in the clinical treatment of ALI.

Lung recruitment by continuous negative extra-thoracic pressure support following one-lung ventilation: an experimental study

Lung recruitment maneuvers following one-lung ventilation (OLV) increase the risk for the development of acute lung injury. The application of continuous negative extrathoracic pressure (CNEP) is gaining interest both in intubated and non-intubated patients. However, there is still a lack of knowledge on the ability of CNEP support to recruit whole lung atelectasis following OLV. We investigated the effects of CNEP following OLV on lung expansion, gas exchange, and hemodynamics. Ten pigs were anesthetized and mechanically ventilated with pressure-regulated volume control mode (PRVC; FiO₂: 0.5, Fr: 30-35/min, VT: 7 mL/kg, PEEP: 5 cmH₂O) for 1 hour, then baseline (BL) data for gas exchange (arterial partial pressure of oxygen, PaO₂; and carbon dioxide, PaCO₂), ventilation and hemodynamical parameters and lung aeration by electrical impedance tomography were recorded. Subsequently, an endobronchial blocker was inserted, and OLV was applied with a reduced VT of 5 mL/kg. Following a new set of measurements after 1 h of OLV, two-lung ventilation was re-established, combining PRVC (VT: 7 mL/kg) and CNEP (-15 cmH₂O) without any hyperinflation maneuver and data collection was then repeated at 5 min and 1 h. Compared to OLV, significant increases in PaO₂ (154.1 ± 13.3 vs. 173.8 ± 22.1) and decreases in PaCO₂ (52.6 ± 11.7 vs. 40.3 ± 4.5 mmHg, p < 0.05 for both) were observed 5 minutes following initiation of CNEP, and these benefits in gas exchange remained after an hour of CNEP. Gradual improvements in lung aeration in the non-collapsed lung were also detected by electrical impedance tomography (p < 0.05) after 5 and 60 min of CNEP. Hemodynamics and ventilation parameters remained stable under CNEP. Application of CNEP in the presence of whole lung atelectasis proved to be efficient in improving gas exchange via recruiting the lung without excessive airway pressures. These benefits of combined CNEP and positive pressure ventilation may have particular value in relieving atelectasis in the postoperative period of surgical procedures requiring OLV.

The anesthesia management of totally thoracoscopic cardiac surgery: A single-center retrospective study

Anesthesia management of Totally thoracoscopic cardiac surgery (TTCS) has been the subject of much debate and discussion. In this single center retrospective study, we summarize the experience of clinical anesthesia management for TTCS by review the medical records of our medical center and look forward to its future development. In this retrospective study, 103 patients (49 male and 54 female) were enrolled, the mean age was 56.7 ± 14.4 years old. The participants underwent Mitral Valve Replacement (MVR) + Tricuspid Valve Annuloplasty (TVA) (42, 40.8%), Mitral Valve Annuloplasty (MVA) + TVA (38, 36.9%), MVA (21, 20.4%), and MVR (2, 1.9%)，respectively. Intraoperative hypoxemia, radiographic pulmonary infiltrates, and pneumonia were observed in 19 (18.4%), 84 (81.6%), and 13 (12.6%) patients, respectively. The LOS of ICU and POD were as follows: MVR + TVA (55.1 ± 25h, 9.9 ± 3.5 d), MVA + TVA (56.5 ± 28.4h, 9.4 ± 4.2d), MVA (37.9 ± 21.9h, 8.1 ± 2.3d) and MVR (48 ± 4.2h, 7.5 ± 2.1d). No reintubation, reoperations, postoperative cognitive dysfunction, 30-day mortality were observed in the present study. The present study demonstrated that applying this anesthesia management for TTCS associated with acceptable morbidity, intensive care unit and postoperative hospital lengths of stay. The finding from the present study might provide some new approach for Anesthesia management of TTCS.

Trelagliptin Alleviates Lipopolysaccharide (LPS)-Induced Inflammation and Oxidative Stress in Acute Lung Injury Mice

Acute lung injury (ALI) is an urgent disease lacking effective therapies, resulting in relatively high morbidity and mortality. The pathological mechanism of ALI is reported to be related to excessive inflammation and activated oxidative stress. The present study aims to investigate the protective effects of the DPP-4 inhibitor Trelagliptin against lipopolysaccharide (LPS)-induced ALI and the underlying mechanism. LPS was used to induce ALI mice models. The pathological condition of ALI mice was evaluated using MPO activity assay, lung wet to dry weight ratio detection, and HE staining on the lung tissues. Lung function was assessed using a spirometer. The oxidative stress level in the lung tissues was checked by MDA measurement and GPx detection using commercial kits. The leukocyte and neutrophil numbers were determined using a hemocytometer and the total concentration of protein in the BALF was detected using a bicinchoninic acid method. The expression levels of TNF-α, IL-6, and CXCL2 in the lung tissues were evaluated using qRT-PCR and ELISA. Western blot analysis was used to determine the expression levels of TLR4 and p-NF-κB p65. LPS-induced elevated MPO activity, pulmonary wet to dry weight ratio, airway resistance (RAW), the total number of leukocytes and neutrophils, production of inflammatory factors, decreased pulmonary dynamic compliance (Cdyn), and peak expiratory flow (PEF), and an aggravated histopathological state (such as disordered alveolar structure, significant pulmonary interstitial edema, and large numbers of red blood cells and inflammatory cells in the alveolar cavity) were significantly reversed by the administration of Trelagliptin. The TLR4/NF-κB signaling pathway was activated and oxidative stress was induced by stimulation with LPS; however, both effects were suppressed by the administration of Trelagliptin. Trelagliptin might alleviate LPS-induced inflammation and oxidative stress in acute lung injury mice.

The Effect of Lidocaine on Postoperative Quality of Recovery and Lung Protection of Patients Undergoing Thoracoscopic Radical Resection of Lung Cancer

PURPOSE

To evaluate the effectiveness and safety of lidocaine on postoperative quality of recovery and lung protection of patients undergoing thoracoscopic radical resection of lung cancer.

PATIENTS AND METHODS

Seventy ASA II-III patients undergoing thoracoscopic radical resection of lung cancer were randomly assigned into either the lidocaine group (Group L) or control group (Group C). Patients in Group L received lidocaine with a 1.5 mg/kg bolus before induction of anesthesia, followed by 2.0 mg/kg/h until the end of the operation while the patients in Group C received volume-matched normal saline at the same rate. The main outcome was the quality of recovery-40 score (QoR-40 score) at 24 h postoperatively. The peak airway pressure (Ppeak) and plateau airway pressure (Pplat), the partial pressure of oxygen in arterial blood (PaO2), partial pressure of carbon dioxide in arterial blood (PaCO2), alveolar-arterial oxygen gradient (A-aDO2), oxygenation index (OI), time to first flatus and defecation, intraoperative hemodynamics and opioid consumption were also recorded.

RESULTS

There were no statistically difference at patients' baseline characteristics. The QoR-40 score of Group L was significantly higher than that of Group C at 24 h after surgery (P=0.014). Ppeak, Pplat, and A-aDO2 of Group L were significantly lower than those of Group C (P<0.001, P<0.001, P=0.025, respectively) after the ventilation recovery of both lungs, and the PaO2 and OI of the Group L were significantly higher than those of Group C (P=0.027, P=0.027, respectively). Time to first flatus and defecation in Group L was significantly lower compared with Group C (P=0.037, P=0.025, respectively).

CONCLUSION

Intravenous lidocaine can improve the quality of recovery of patients undergoing thoracoscopic radical resection of lung cancer, while also providing lung protection, favorable postoperative analgesia, a reduction in the time to first flatus and defecation after surgery.

Etomidate Regulates miR-192-5p Expression to Reduce Hypoxia-Reoxygenation Induced Bronchial Epithelial Cell Damage

Etomidate is a new type of intravenous anesthetic that can protect bronchial epithelial cells from oxidative stress damage. miR-192-5p is upregulated in 6-hydroxydopamine-induced neurocytes. This study explored the effect of etomidate on bronchial epithelial cell apoptosis and oxidative stress induced by hypoxia and reoxygenation and its regulatory effect on miR-192-5p. The human bronchial epithelial cells BEAS-2B were cultured in vitro and then subjected to hypoxia and reoxygenation to establish a cell injury model. The cells were then treated with etomidate at different doses. Moreover, anti-miR-NC and anti-miR-192-5p were transfected into the BEAS-2B cells to treat the hypoxia-reoxygenation. Moreover, miR-NC and miR-192-5p mimics were transfected into BEAS-2B cells, followed by treatment with 90 µmol/L etomidate for 24 h and then treatment with hypoxia and reoxygenation. The 2,4-dinitrophenylhydrazine method was used to determine the level of LDH in the culture medium of cardiomyocytes. Thiobarbituric acid was used to determine the level of MDA and xanthine oxidase to determine the activity of SOD. Flow cytometry was used to measure the apoptosis rate and qRT-PCR to evaluate miR-192-5p expression. Western blotting was used to determine the Bax and Bcl-2 protein levels. Compared with the findings in the control group, the levels of LDH and MDA, the apoptosis rate, and the protein level of Bax were increased (P < 0.05) upon treatment with hypoxia and reoxygenation, while SOD activity and Bcl-2 protein level were decreased (P < 0.05). In a manner dependent on the dose, etomidate could significantly reverse the effects of hypoxia and reoxygenation on oxidative stress and apoptosis of BEAS-2B cells (P < 0.05). Hypoxia and reoxygenation could significantly increase the miR-192-5p level of BEAS-2B cells (P < 0.05), while etomidate could reduce this miR-192-5p expression (P < 0.05) in a dose-dependent manner. Transfection of anti-miR-192-5p dramatically reduced LDH, MDA, apoptosis rate, and Bax protein level (P < 0.05), but was associated with increases of SOD activity and Bcl-2 protein expression (P < 0.05). High expression of miR-192-5p could significantly reverse the influence of etomidate on apoptosis and oxidative stress of BEAS-2B cells induced by hypoxia-reoxygenation (P < 0.05). Etomidate restrained the apoptosis of bronchial epithelial cells and oxidative stress induced by hypoxia and reoxygenation by inhibiting miR-192-5p expression, thereby reducing cell damage.

[Dexmedetomidine combined with protective lung ventilation strategy provides lung protection in patients undergoing radical resection of esophageal cancer with one-lung ventilation]

OBJECTIVE

To investigate the effect of dexmedetomidine combined with pulmonary protective ventilation against lung injury in patients undergoing surgeries for esophageal cancer with one-lung ventilation (OLV).

METHODS

Forty patients with undergoing surgery for esophageal cancer with OLV were randomly divided into pulmonary protective ventilation strategy group (F group) and dexmedetomidine combined with protective ventilation strategy group (DF group; n=20). In F group, lung protective ventilation strategy during anesthesia was adopte, and in DF group, the patients received intravenous infusion of dexmedetomidine hydrochloride (0.3 μg · kg^-1 ·h^-1) during the surgery starting at 10 min before anesthesia induction in addition to protective ventilation strategy. Brachial artery blood was sampled before ventilation (T₀), at 30 and 90 min after the start of OLV (T₁ and T₂, respectively) and at the end of the surgery (T₃) for analysis of superoxide dismutase (SOD), malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), arterial oxygenation pressure (PaO₂), oxygenation index (OI) and lung compliance (CL).

RESULTS

At the time points of T₁, T₂ and T₃, SOD level was significantly higher and IL-6 level was significantly lower in the DF group than in F group (P &lt; 0.05). The patients in DF group showed significantly higher PaO₂, OI and CL index than those in F group at all the 3 time points.

CONCLUSIONS

Dexmedetomidine combined with pulmonary protective ventilation strategy can reduce perioperative lung injury in patients undergoing surgery for esophageal cancer with OLV by suppressing inflammation and oxidative stress to improve lung function and reduce adverse effects of the surgery.

Effect of Transcutaneous Electrical Acupoint Stimulation on One-Lung Ventilation-Induced Lung Injury in Patients Undergoing Esophageal Cancer Operation

OBJECTIVE

To investigate the effect of transcutaneous electrical acupoint stimulation (TEAS) on one-lung ventilation-induced injury in patients undergoing esophageal cancer operation.

METHODS

The participants (n = 121) were randomly assigned into TEAS and sham groups. The TEAS group was given transcutaneous electrical stimulation therapy. The acupoints selected were Feishu (BL13), Hegu (L14), and Zusanli (ST36) and were treated 30 minutes before induction of anesthesia; treatment lasts 30 minutes. The sham group was connected to the electrode on the same acupoints, but electronic stimulation was not applied. The levels of oxygenation index (PaO2/FiO2) and alveolar-arterial oxygen tension difference (A-aDO2) before one-lung ventilation (T1), 30 minutes after one-lung ventilation (T2), 2 hours after one-lung ventilation (T3), and 1 hour after the operation (T4) and the levels of serum tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-10 (IL-10) at T1, T2, T3, and 24 hours after the operation (T5) were taken as the primary endpoints. The incidence of postoperative pulmonary complications, removal time of thoracic drainage tube, and length of hospital stay were taken as the secondary endpoints.

RESULTS

Compared with that, in the sham group, the level of PaO2/FiO2 in the TEAS group was significantly increased at T2, T3, and T4, and the level of A-aDO2 was significantly reduced at T2 and T3 (P < 0.05). Besides, compared with that, in the sham group, the level of serum TNF-α at T2, T3, and T5, as well as the level of serum IL-6 at T3 and T5, was significantly reduced, whereas the level of serum IL-10 at T3 was significantly increased (P < 0.05). The incidences of pulmonary infection and pleural effusion in the TEAS group were significantly lower than that in the sham group, and the removal time of thoracic drainage tube and the length of hospital stay in the TEAS group were significantly shorter than that in the sham group (P < 0.05).

CONCLUSIONS

TEAS could effectively increase the levels of PaO2/FiO2 and IL-10, reduce the levels of A-aDO2, TNF-α, and IL-6, and reduce the incidence of pulmonary complications. Moreover, it could also contribute to shorten the removal time of thoracic drainage tube and the length of hospital stay.