Biomechanical strength dependence on mammalian airway length.

BACKGROUND: The trachea is the uppermost respiratory airway element connecting the larynx to the bronchi Airway reconstructions in humans are often developed from animal models but there is limited knowledge comparing tracheal biomechanics between species. We aimed to assess the structure and biomechanics of porcine, canine, caprine and human airways. METHODS: Tracheas from pigs (n=15), goats (n=9) and canines (n=9) were divided into three groups (4, 6 and 8-ringswhile human left principal brochi (n=12) were divided into two groups (3and-rings). Airway structures were compared using histology and scanning electron microscopy. Biomechanical properties were measured subjecting samples to uniaxial tension and compression, recording the elastic modulus and (tensile and compressive) strengths. RESULTS: The structures of animal tracheal and human bronchia appeared similar. Biomechanical testing revealed that the elastic modulus of 8-ring tracheas was 1,190.48±363.68, 2,572.00±608.19 and 1,771.27±145.54 kPa, for porcine, canine and caprine samples, respectively, while corresponding tensile strengths were 437.63±191.41, 808.38±223.48 and 445.76±44.00 kPa. Comparable measures of anterior-posterior (A-P) compression strengths were 7.94±0.82, 7.54±0.07 and 8.10±1.87 N, respectively, whereas lateral compression strengths were 8.75±0.82, 14.55±2.29 and 11.12±0.40 N. Compression testing of human samples showed significant differences (P<0.05) between the 3-ring (A-P, 1.06±0.02 N; lateral, 0.55±0.06 N) and 5-ring groups (A-P, 1.08±0.64 N; lateral, 2.32±1.95 N). CONCLUSIONS: The tensile and compressive strengths of mammalian airways show positive correlations with the cartilage ring number (length). On the basis of structural and biomechanical comparisons, porcine, canine and caprine species appear suitable models for the study of airway reconstruction in human.

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.

EphB4 gene polymorphism and protein expression in non-small-cell lung cancer.

The objective of this study was to identify new diagnostic, prognostic or therapeutic molecules for non-small- cell lung cancer (NSCLC). We investigated the expression of EphB4, a tyrosine kinase receptor which has been shown to act as a tumor promoter in other cancers. Using immunohistochemistry, we visualized EphB4 expression in 28 samples of NSCLC and 12 samples of adjacent normal tissues. Additionally, we assessed a single-nucleotide polymorphism in EphB4 to determine its effect on protein expression. The correlation of both genotype and protein expression with disease severity was determined. EphB4 was expressed in 53.6% of patients with lung cancer, a significant increase compared to control lung samples (0.0%, P<0.05). Furthermore, EphB4 expression was correlated with differentiation, lymph node metastasis and TNM stage of tumors (P<0.05). Additionally, the polymorphism in EphB4 at rs314310 appeared to correspond to protein expression and disease susceptibility. While the frequencies of CC, CA and AA genotypes were not different between lung cancer patients and healthy controls, the frequencies of C and A alleles were significantly different between these groups (P<0.05). Further analysis showed that the positive rate of EphB4 expression in patients with the AA genotype was significantly higher compared to that in patients with other genotypes (P<0.05). Overexpression of EphB4 plays a role in the occurrence and development of NSCLC, and the polymorphism at rs314310 may predispose individuals to this disease.

Lung transplantation for end-stage silicosis.

OBJECTIVE: To evaluate whether lung transplantation conferred acceptable survival compared with conventional treatment for end-stage silicosis. METHODS: We retrospectively analyzed data for five consecutive patients with silicosis between September 2002 and December 2010, four underwent single lung transplantation and one bilateral lung transplantation. RESULTS: There was no perioperative mortality. Extracorporeal membrane oxygenation was required in four patients, three underwent single lung transplantation and one received bilateral lung transplantation, three of them were successfully weaned. One developed primary graft dysfunction 2 days after transplant and died of multiple organ failure on postoperative day 8. The remaining four patients were discharged from hospital. During follow-up, one recipient died of severe infection 7 months after transplant. All remaining patients returned to work and had a good quality of life after 5, 3 and 2 years, respectively. CONCLUSIONS: Lung transplantation offers effective therapy for patients with end-stage silicosis.

[Lung transplantation for silicosis: a report of 5 cases].

OBJECTIVE: To investigate the selection of recipients, operative technique, and perioperative management of lung transplantation for silicosis. METHODS: Lung transplantations (LTx) were performed for five end-stage silicosis in our hospital who were diagnosed in accordance with recommendations of the local Prophylactic Therapeutic Institution for Occupational Diseases. The chest roentgenogram and high resolution CT showed somewhat pulmonary interstitial fibrosis, pulmonary emphysema and massive opacities. The mean pulmonary artery pressure (mPAP) was > 30mmHg, NYHA III or IV. Two patients received thoracic surgery prior to LTx, one patient was ventilator-dependent. One patient received bilateral sequence lung transplantation (BSLT) under extracorporeal membrane oxygenation (ECMO) support. Four patients received single lung transplantation (SLT), 3 under ECMO support. RESULTS: Patient five died of multiple organ failure on postoperative day 8, the remaining four patients were discharged from hospital. During follow up, patient three died of severe infection 7 month postoperatively, the remaining three patients were alive for 5 years, 3 years and 2 years respectively, and lived good quality of life, especially with lower mPAP and improved lung function. Although our patients suffered low-grade chronic rejection with the manifestation of bronchiolitis obliterative syndrome (BOS). CONCLUSION: Lung transplantation is a viable option for patients with end-stage silicosis, providing acceptable quality of life and survival. Both SLT and BSLT are satisfactory approach for end-stage silicosis,and long-term survival requires further investigations.

[Lung transplantation for pulmonary fibrosis: report of 10 cases].

OBJECTIVE: To discuss the operative technique, patient selection and perioperative management of lung transplantation for pulmonary fibrosis. METHODS: From September 2002 to December 2005, 31 cases of lung transplantations were performed in our hospital. There were 10 cases receiving single lung transplantation for pulmonary fibrosis, among them 2 received right lung transplantation with cardio pulmonary bypass, and one received contralateral lung transplantation-a left donor lung implanted in the recipient's right thorax. RESULTS: The in-hospital mortality was 10.0% (1/10). Nine patients were discharged from hospital, while one patient died of severe infection on the 137th postoperative day. During follow-up, one patient died of infection 9 months and another patient died of an accident 25 months after the operation. The 7 other patients were alive with improved lung functions. CONCLUSION: Lung transplantation is effective in improving the survival of selected patients with idiopathic pulmonary fibrosis.

[The operative technique selection of lung transplantation for end-stage emphysema].

OBJECTIVE: To investigate the operation of lung transplantation for end-stage emphysema. METHODS: From September 2002 to February 2005, 9 patients with chronic obstructive pulmonary disease (COPD) underwent lung transplantation. The types of surgery included single lung transplantation in 2 patients, lung transplantation with asynchronous contralateral lung volume reduction (one week later) in 1, single lung transplantation with synchronized contralateral lung volume reduction in 4, and bilateral sequential lung transplantation without cardiopulmonary bypass in 2. RESULTS: The volume of chest drainage was more than 2000 ml at the first postoperative day in 2 patients, one was reoperated for hemostasis and another was successfully responded to conservative therapy. The ventilation time was ranged from 3 to 22 days postoperatively. Two patients were received tracheotomy. Seven patients achieved good results, two of them had returned to work, and 1 patient had lived for 30 months. One patient was died of severe acute rejection (4A) at 15th postoperative day and 1 succumbed to multisystem organ failure due to severe bacterial infection combine fungal infection. CONCLUSION: End-stage emphysema is an indication for single lung transplantation. Single lung transplantation with contralateral lung volume reduction is a good way to utilize donor. If patient suffered from infection, double-lung transplantation should be considered first.

[Single-lung transplantation and contralateral lung volume reduction for emphysema].

OBJECTIVE: To report the operation technique, patient selection and curative effect of single-lung transplantation with contralateral lung volume reduction for a patient with end-stage emphysema. METHODS: A 47-year-old male patient who was dependent on mechanical ventilation because of end-stage emphysema received left-lung transplantation on 20 June, 2003. The surgical technique used was similar to that mentioned in the literature. The donor lung was perfused by low-potassium dextran solutions (LPD) with a cold ischemic time of 390 minutes. The patient received contralateral lung volume reduction because of subacute native lung hyperinflation on the 7th day after operation. He was received tracheostomy on 15th day after operation and was weaned from ventilator on the 26th day post-operation. Immunosuppression included cyclosporine, mycophenolate mofetil and corticosteroid. The acute rejection occurred on the 9th and 15th days after operation and was cured successfully. RESULTS: The lung function was improved significantly and the patient was discharged from hospital 71 days after operation. CONCLUSIONS: Single-lung transplantation combined with contralateral lung volume reduction for end-stage emphysema is an effective measure for subacute native lung hyperinflation. Further follow-up is required to assess the long term results of this procedure.

[Single-lung transplantation for end-stage emphysema].

OBJECTIVE: To evaluate operative technique, patient selection and perioperative management of single-lung transplantation for a patients with end-stage emphysema. METHODS: A 56-year-old patient with end-stage emphysema underwent left-lung transplantation on September 28, 2002. The surgical technique used was similar to that mentioned in the literature. The donor lung was perfused by LPD solution with a cold ischemic time of 260 minutes. Cardiopulmonary bypass was not performed. RESULTS: The patient weaned from a ventilator at the 93th hour after operation. Immunosuppressants included cyclosporine, mycophenolate mofetil and corticosteroid. Acute rejection occurred on the ninth day after operation and was cured by bolus methylprednisolone given intravenously. Lung function was improved significantly and the patient was discharged from the hospital on the 47th day after operation. CONCLUSION: Single-lung transplantation for patients with end-stage emphysema is effective for long-term improvement of pulmonary function.