Metformin alleviates lung ischemia-reperfusion injury in a rat lung transplantation model.

Background: Lung ischemia-reperfusion injury (LIRI) is among the complications observed after lung transplantation and is associated with morbidity and mortality. Preconditioning of the donor lung before organ retrieval may improve organ quality after transplantation. We investigated whether preconditioning with metformin (Met) ameliorates LIRI after lung transplantation. Methods: Twenty Lewis rats were randomly divided into the sham, LIRI, and Met groups. The rats in the LIRI and Met groups received saline and Met, respectively, via oral gavage. Subsequently, a donor lung was harvested and kept in cold storage for 8 h. The LIRI and Met groups then underwent left lung transplantation. After 2 h of reperfusion, serum and transplanted lung tissues were examined. Results: The partial pressure of oxygen (PaO2) was greater in the Met group than in the LIRI group. In the Met group, wet-to-dry (W/D) weight ratios, inflammatory factor levels, oxidative stress levels and apoptosis levels were notably decreased. Conclusions: Met protects against ischemia-reperfusion injury after lung transplantation in rats, and its therapeutic effect is associated with its anti-inflammatory, antioxidative, and antiapoptotic properties.

Parecoxib sodium attenuates acute lung injury following burns by regulating M1/M2 macrophage polarization through the TLR4/NF-κB pathway.

High temperature-induced burn injury often leads to an excessive inflammatory cascade resulting in multiple organ dysfunction syndrome, such as acute lung injury (ALI), in addition to skin tissue damage. As a specific COX2 inhibitor, parecoxib sodium suppresses the inflammatory response during burn injury. The effect of parecoxib sodium on ALI induced by burn injury and the associated molecular mechanism still need to be investigated. The role of parecoxib sodium in burn injury-induced ALI through the TLR4/NF-κB pathway was explored in the present study. A burn-induced ALI mouse model was constructed, and M1/M2 macrophages in lung tissue and markers involved in the TLR4/NF-κB signalling pathway were evaluated in bronchoalveolar lavage fluid (BALF) and MH-S mouse alveolar macrophages in vitro. The results indicated that parecoxib sodium attenuated lung injury after burn injury, decreased iNOS and TNF-α expression, increased IL-10 expression in BALF, and regulated the CD86-and CD206-mediated polarization of M1/M2 macrophages in lung tissue along with MH-S mouse alveolar macrophages. The effect of parecoxib sodium might be reversed by a TLR4 agonist. Overall, the results suggested that parecoxib sodium can regulate the polarization of M1/M2 macrophages through the TLR4/NF-κB pathway to attenuate ALI induced by skin burns.

[Risk factors of early death after lung transplantation in patients with idiopathic pulmonary fibrosis complicated with pulmonary arterial hypertension].

OBJECTIVE: To investigate the risk factors of early death after lung transplantation in patients with idiopathic pulmonary fibrosis (IPF) complicated with pulmonary arterial hypertension (PAH). METHODS: A retrospective cohort study was conducted. The clinical data of 134 patients with IPF and PAH who underwent lung transplantation at Wuxi People's Hospital Affiliated to Nanjing Medical University from January 2017 to December 2020 were collected. The donor's gender, age, duration of mechanical ventilation, and cold ischemia time, the recipient's gender, age, body mass index (BMI), smoking, history of hypertension and diabetes, preoperative usage of hormones, mean pulmonary arterial pressure (mPAP), cardiac echocardiography and cardiac function, serum creatinine (SCr), N-terminal pro-brain natriuretic peptide (NT-proBNP) as well as surgical type, extracorporeal membrane oxygenation (ECMO) treatment, duration of operation, and plasma and red blood cell infusion ratio were collected. The cumulative survival rates of patients at 30, 60, and 180 days after lung transplantation were calculated by Kaplan-Meier method. The univariate and multivariate Cox proportional hazards regression models were used to analyze the effects of donor, recipient, and surgical factors on early survival in donors after lung transplantation. RESULTS: The majority of donors were male (80.6%). There was 63.4% of the donors older than 35 years old, 80.6% of the donors had mechanical ventilation duration less than 10 days, and the median cold ischemia time was 465.00 (369.25, 556.25) minutes. The recipients were mainly males (83.6%). Most of the patients were younger than 65 years old (70.9%). Most of them had no hypertension (75.4%) or diabetes (67.9%). The median mPAP of recipients was 36 (30, 43) mmHg (1 mmHg ≈ 0.133 kPa). There were 73 patients with single lung transplantation (54.5%), and 61 with double lung transplantation (45.5%). The survival rates of 134 IPF patients with PAH at 30, 60, 180 days after lung transplantation were 81.3%, 76.9%, and 67.4%, respectively. Univariate Cox proportional risk regression analysis showed that recipient preoperative use of hormone [hazard ratio (HR) = 2.079, 95% confidence interval (95%CI) was 1.048-4.128], mPAP ≥ 35 mmHg (HR = 2.136, 95%CI was 1.129-4.044), NT-proBNP ≥ 300 ng/L (HR = 2.411, 95%CI was 1.323-4.392), New York Heart Association (NYHA) cardiac function classification III-IV (HR = 3.021, 95%CI was 1.652-5.523) were the risk factors of early postoperative death in patients with IPF complicated with PAH (all P < 0.05). In the multivariable Cox proportional risk regression analysis, recipient preoperative hormone usage (model 1: HR = 2.072, 95%CI was 1.044-4.114, P = 0.037; model 2: HR = 2.098, 95%CI was 1.057-4.165, P = 0.034), NT-proBNP ≥ 300 ng/L (HR = 2.246, 95%CI was 1.225-4.116, P = 0.009) and NYHA cardiac function classification III-IV (HR = 2.771, 95%CI was 1.495-5.134, P = 0.001) were independent risk factors of early postoperative death in patients with IPF. CONCLUSIONS: Preoperative hormone usage, NT-proBNP ≥ 300 ng/L, NYHA cardiac function classification III-IV are independent risk factors for early death in patients with IPF and PAH after lung transplantation. For these patients, attention should be paid to optimize their functional status before operation. Preoperative reduction of receptor hormone usage and improvement of cardiac function can improve the early survival rate of such patients after lung transplantation.

Cervical sympathetic trunk transection alleviates acute lung injury caused by intestinal obstruction via inhibition of phospholipase A2 in rats.

BACKGROUND: Intestinal obstruction can result in inflammatory injury to distant organs, especially the lungs. Stellate ganglion block (SGB) provides sympathetic nervous homeostasis and inhibits the systemic inflammatory response. This study aimed to investigate whether SGB can alleviate acute lung injury by inhibiting phospholipase A2 expression in rats. METHODS: Thirty healthy male Sprague-Dawley rats were divided into three groups: C group (sham-operated); CLP group (cecal ligation and puncture with intestinal obstruction), and cervical sympathetic trunk transection (CSTT) group (transection of the cervical sympathetic trunk following CLP).Arterial blood samples were obtained to determine the ratio of partial arterial pressure of oxygen (PaO2) to fraction of oxygen in inspired air (FiO2). Venous blood samples were used to evaluate the serum concentrations of chemokines, tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-10 using enzyme-linked immunosorbent assays. Following euthanasia, the lungs were isolated to estimate the wet/dry lung weight (W/D) ratio, evaluate the pathological damage to lung tissues on microscopy, and determine secretory-type phospholipase A2 (sPLA2) expression using western blotting. RESULTS: Rats in the CLP group showed increased fatigue, decreased activity levels, and coarse, gray hair. The levels of chemokines, TNF-α, and IL-6 in the CLP and CSTT groups were higher than those in the C group. However, the levels were lower in the CSTT group than those in the CLP group. IL-10 levels in the CLP group were higher and lower than those in the C and CSTT groups, respectively. W/D ratios and PaO2/FiO2 in the CLP and CSTT groups were higher than those in the C group, whereas these ratios in the CSTT group were lower than those in the CLP group. No lung injury was noted in group C, and the lung injury scores were lower in the CSTT group than those in the CLP group. sPLA2 expression levels in the CLP group were higher than those in the C group, whereas these levels in the CSTT group were lower than those in the CLP group. CONCLUSIONS: sPLA2 overexpression in the lungs may be a pathogenic factor in acute lung injury. CSTT alleviated acute lung injury by inhibiting sPLA2 expression.

Preoperative Acute Pain Is Associated with Postoperative Delirium.

BACKGROUND: Studies have provided some evidence that pain is a risk factor for postoperative delirium (POD). Therefore, we investigated the relationship between preoperative pain and POD after noncardiac surgery. METHODS: POD was assessed with the Montreal Cognitive Assessment, and preoperative cognition was assessed with the Mini-Mental State Examination. Plasma C-reactive protein (CRP) was detected by enzyme-linked immunosorbent assay before surgery. Preoperative pain was classified by its duration before surgery as chronic pain (lasting more than 1 month), acute pain (lasting less than 1 month), or no pain (no obvious pain). Multiple linear regression was used to adjust for confounding. RESULTS: From October 15, 2018, through August 12, 2019, a total of 67 patients were randomized; 7 were excluded because they were discharged before the seventh postoperative day. The prevalence of POD was significantly higher in the acute pain group (13 of 20; 65%) than in the chronic pain group (5 of 20; 25%) or the no pain group (6 of 20; 30%) (P = 0.019), indicating that delirium is associated with preoperative acute pain. The plasma level of preoperative CRP was also higher in the acute pain group than in the other two groups (mean [interquartile range]: 10.7 [3.3, 29.3] vs 1 [0.5, 3.8]mg/l; P < 0.001), suggesting that elevated preoperative plasma levels of CRP were associated with delirium. CONCLUSIONS: Preoperative acute pain was associated with POD, and increased plasma levels of CRP provide a marker. In addition, we found that illiteracy and advanced age were risk factors for POD.

[Concomitant use of peripheral veno-venous extracorporeal membrane oxygenation (VV-ECMO) and central veno-arterial ECMO during lung transplantation for coronavirus disease 2019 patients].

OBJECTIVE: To summarize the strategy of using extracorporeal membrane oxygenation (ECMO) support during lung transplantation from 2 coronavirus disease 2019 (COVID-19) with end-stage respiratory failure. METHODS: Two COVID-19 with end-stage respiratory failure patients were admitted to Nanjing Medical University Affiliated Wuxi People's Hospital in March 2020. As the homoeostasis and vital signs could not be maintained in balance by conventional treatments, lung transplantations were performed. Here, detail information about combined application of peripheral veno-venous ECMO (VV-ECMO) and central veno-arterial ECMO (CVA-ECMO) during the operation will be discussed. RESULTS: Case 1: 59 years old, 172 cm height, 72 kg weight, who received mechanical ventilation for 22 days, tracheotomy tube for 17 days, and VV-ECMO support for 7 days. Case 2: 72 years old, 178 cm height, 71 kg weight, who received mechanical ventilation for 19 days, tracheotomy tube for 17 days, and VV-ECMO support for 18 days. As both of them have severe COVID-19-associated respiratory failure, and the recovery was determined to be unlikely, lung transplantations were performed. Severe pulmonary arterial hypertension (PAH) and cardiac insufficiency were found during the operation. Based on preoperative VV-ECMO, CVA-ECMO was added. The concomitant use of peripheral VV-ECMO and CVA-ECMO offered satisfied intraoperative oxygenation and cardiopulmonary status,the operations run smoothly, and the CVA-ECMO was successfully removed, no ECMO-related complications occurred. CONCLUSIONS: The combined use of VV-ECMO and CVA-ECMO is an optimal strategy in the end-stage ARDS patients with severe PAH and cardiac insufficiency, which can offer benefits on respiratory and cardiac functions simultaneously, and ensure surgery safety.

Preoperative Chronic and Acute Pain Affects Postoperative Cognitive Function Mediated by Neurotransmitters.

The effective prevention of postoperative cognitive dysfunction (POCD) needs to be explored, and the effect of preoperative pain on POCD remains unclear. We established a chronic pain model induced by chronic constriction injury (CCI) and models of acute pain and anxiety without pain in mice that were subsequently subjected to partial hepatectomy surgery. Morris water maze (MWM) tests were performed to evaluate the learning and memory abilities of the mice. ELISA was used to measure IL-1ß, IL-6, and TNF-α in serum, and HPLC-MS was used to detect neurotransmitters in the prefrontal cortices and hippocampi of the mice. The results indicated that chronic pain induced by CCI might have significantly impaired the learning and memory abilities of mice, while acute pain and anxiety without pain only affected the memory abilities of mice. Perioperative acute pain increased the level of IL-1ß in serum, and CCI might have increased the level of IL-6. CCI and acute pain increased dopamine (DA) levels in the cortex, similar to anxiety. Like anxiety, CCI increased 5-hydroxytryptamine (5-HT) levels in the prefrontal cortex and hippocampus. Acute pain led to a decrease in the acetylcholine (ACH) level in the hippocampus. Our results suggest that acute pain and CCI-induced chronic pain might aggravate postoperative cognitive dysfunction via neurotransmitters and by changing the levels of inflammatory factors such as IL-1ß and IL-6.

Lung transplantation as therapeutic option in acute respiratory distress syndrome for coronavirus disease 2019-related pulmonary fibrosis.

BACKGROUND: Critical patients with the coronavirus disease 2019 (COVID-19), even those whose nucleic acid test results had turned negative and those receiving maximal medical support, have been noted to progress to irreversible fatal respiratory failure. Lung transplantation (LT) as the sole therapy for end-stage pulmonary fibrosis related to acute respiratory distress syndrome has been considered as the ultimate rescue therapy for these patients. METHODS: From February 10 to March 10, 2020, three male patients were urgently assessed and listed for transplantation. After conducting a full ethical review and after obtaining assent from the family of the patients, we performed three LT procedures for COVID-19 patients with illness durations of more than one month and extremely high sequential organ failure assessment scores. RESULTS: Two of the three recipients survived post-LT and started participating in a rehabilitation program. Pearls of the LT team collaboration and perioperative logistics were summarized and continually improved. The pathological results of the explanted lungs were concordant with the critical clinical manifestation, and provided insight towards better understanding of the disease. Government health affair systems, virology detection tools, and modern communication technology all play key roles towards the survival of the patients and their rehabilitation. CONCLUSIONS: LT can be performed in end-stage patients with respiratory failure due to COVID-19-related pulmonary fibrosis. If confirmed positive-turned-negative virology status without organ dysfunction that could contraindicate LT, LT provided the final option for these patients to avoid certain death, with proper protection of transplant surgeons and medical staffs. By ensuring instant seamless care for both patients and medical teams, the goal of reducing the mortality rate and salvaging the lives of patients with COVID-19 can be attained.

The prognostic value of peak arterial lactate levels within 72 h of lung transplantation in identifying patient outcome.

BACKGROUND: Lactic acidosis is often seen in lung transplantation (LTx). Postoperative lactate is frequently associated with poor outcome in postoperative and critically ill patients. Our aim was to evaluate the predictive value of postoperative peak lactate levels within 72 h of LTx for 30-day and late mortality. METHODS: We evaluated patients who underwent LTx from January 2015 to September 2017. All admitted patients were classified according to the peak lactate level (PL) within 72 h of surgery: PL <5 mmol/L (Group 1); PL =5-10 mmol/L (Group 2), and PL >10 mmol/L (Group 3). We performed logistic regression analysis and used Cox regression models to identify the peak lactate level as a predictive factor for 30-day and late mortality, respectively. RESULTS: Of 255 eligible patients, mean age 55.61±12.16, mean lactate 4.99±2.93 and 80% male, and 40% had hyperlactatemia (PL >5 mmol/L) after LTx. The 30-day mortality rate was 17.9%, 28.9% and 68.8% in the three groups, respectively (P<0.05). Multivariate regression analyses revealed postoperative PL as a notable predictor of 30-day mortality [odds ratio =2.62 (1.42-4.84), P=0.002] as well as for late mortality [hazard ratio =2.70 (1.13-6.42), P=0.025]. CONCLUSIONS: The postoperative peak lactate level within 72 h of surgery was an independent predictor for 30-day and late mortality in LTx patients.

Intrathecal injection of dexmedetomidine ameliorates chronic neuropathic pain via the modulation of MPK3/ERK1/2 in a mouse model of chronic neuropathic pain.

Objective: Despite the application of dexmedetomidine (DEX) as a perioperative adjuvant in local analgesia, the exact analgesic mechanism underpinning chronic neuropathic pain (CNP) awaits our elucidation. Methods: We investigated the molecular mechanisms of the anti-nociceptive effect of DEX on neuropathic pain in a mouse model induced by chronic constriction injury (CCI). Results: DEX administration significantly increased the paw withdrawal latency (PWL) values 0.5 to 2 h post-injection in CCI-induced CNP mice at day 5 to 21 versus dimethyl sulfoxide (DMSO)-treated mice, confirming its analgesic effect. The c-Fos expression was significantly elevated in CCI mice versus the sham-operated group, whereas the elevation was mitigated by DEX injection. Subsequently, the involvement of MKP1 and MKP3 in the pathogenesis of chronic neuropathic pain was evaluated. Western blotting analyses revealed significant decrease in both MKP1 and MKP3 in the spinal cord in CCI group versus the sham group. DEX markedly elevated the MKP3 expression and modestly reduced the MKP1 expression, with insignificant difference in the latter. Co-injection of BCI (an MKP3 inhibitor) and DEX evidently reduced the PWL values in CCI mice. Furthermore, DEX significantly downregulated the phosphorylation of extracellular-signal-regulated kinase (ERK) 1/2, down-stream effector of MKP3 in CCI mice, whereas the downregulation was reversed by BCI. Conclusion: We confirmed that DEX exerts the analgesic effect on chronic neuropathic pain via the regulation of MKP3/ERK1/2 signaling pathway, which may contribute to clarification of the molecular mechanism and novel therapy for chronic neuropathic pain.

Electroacupuncture Pretreatment Attenuates Inflammatory Lung Injury After Cardiopulmonary Bypass by Suppressing NLRP3 Inflammasome Activation in Rats.

Cardiopulmonary bypass (CPB) can induce inflammatory lung injury, which is a common complication during cardiac surgery. Nod-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome-induced inflammation plays a crucial role in lung injury after CPB. Previous studies have shown that electroacupuncture (EA) has potential anti-inflammatory activity. However, the role of EA in CPB is poorly understood. The aim of this study was to determine whether EA was associated with CPB-induced inflammatory lung injury. In the present study, rats were treated with EA for 5 days before CPB. Two hours after CPB, the lung tissue, serum, and bronchoalveolar lavage fluid (BALF) were prepared for assessment. Our results showed that the expression of NLRP3 in the lung tissue increased significantly after CPB. The EA pretreatment suppressed NLRP3 inflammasome activation, reduced lung edema, and inhibited IL-1ß release into the serum and BALF after CPB. Our findings suggest that EA pretreatment attenuates inflammatory lung injury after CPB by suppressing NLRP3 inflammasome activation.

Decreased analgesic effect of morphine, but not buprenorphine, in patients with advanced P-glycoprotein(+) cancers.

BACKGROUND: P-glycoprotein (P-gp) is expressed on the blood-brain barrier (BBB) and acts as a transporter regulating the analgesic effect of morphine. The P-gp is also expressed by different types of tumors. The aim of this study was to determine the potential association of the P-gp expression in malignant tumors with analgesic effects in patients. METHODS: The P-gp expression in 120 malignant tumors was examined by immunohistochemistry. The analgesic responses of individual patients to morphine and buprenorphine (BNP) were evaluated by visual analog scale (VAS). The levels of plasma morphine and BNP were determined by HPLC. RESULTS: We found that there was no significant difference in the values of VAS between patients with P-gp(+) and P-gp(-) malignant tumors in responses to 0.000025 g x kg(-2) of BNP administered by patient-controlled intravenous analgesia (PCIA), accompanied by similar levels of plasma BNP in those patients. In contrast, the values of VAS in response to 0.00075 g x kg(-2) of morphine in patients with P-gp(+) tumors were significantly greater than those in the patients with P-gp(-) tumors, although similar levels of plasma morphine were detected in both groups of patients. Furthermore, treatment with a higher dose (0.0011 g x kg(-2)) of morphine effectively controlled pain in those with P-gp(+) tumors. CONCLUSION: Our data indicated that patients with P-gp(+) tumors required a higher dose of morphine to achieve an analgesic effect and that the P-gp expression in tumors may be valuable for predicting the analgesic responses of patients with severe pain to morphine.