[Primary graft dysfunction after lung transplantation]

Expression of Claudin-4 in Lung Ischemia-Reperfusion Injury in Experimental Lung Transplantation

OBJECTIVE

To assess the presence of CLDN4 in bronchoalveolar lavage fluid (BALF) and pulmonary tissue as an early indicator of LIRI and its relationship with changes in pulmonary physiology, edema formation and histology in an experimental porcine model of LTx with CIT of 50 min or 6 h.

METHODS

In 12 pigs, LIRI was produced by: group I (n = 6) LTx with 50 min of CIT (LTx-50 min-CIT); and group II (n = 6) LTx with 6 h of CIT (LTx-6h-CIT). The lung function, edema formation, macroscopic and microscopic changes were assessed. CLDN4 expression in BALF and pulmonary tissue were determined.

RESULTS

Both groups presented similar clinical, edema, and histological damage, as well as similar expression of CLDN4 in BALF and tissue (p > 0.05, RM-ANOVA).

CONCLUSION

CLDN4 expressed in BALF and the pulmonary tissue during the first 5 h within 72 h of the PGD window are not associated by the deterioration of lung function, edema and lung histological injury, in LTx with CIT 50 min or 6 h, CLDN4 does not seem to be a valuable indicator of LIRI.

An extracellular oxygen carrier during prolonged pulmonary preservation improves post-transplant lung function

BACKGROUND

The use of a novel extracellular oxygen carrier (EOC) preservation additive known as HEMO2Life has recently been shown to lead to a superior preservation of different types of solid organs. Our study aimed to investigate the effect of this EOC on extending lung preservation time and its mechanism of action.

METHODS

Donor pigs were randomly allocated to either of the following 2 groups (n = 6 per group): (1) 36 hours cold preservation or (2) 36 hours cold preservation with 1 g/liter of EOC. The lungs were evaluated through 12 hours of normothermic ex vivo lung perfusion (EVLP) followed by a left-single lung transplant into a recipient pig. Grafts were reperfused for 4 hours, followed by right pulmonary artery clamping to assess graft oxygenation function.

RESULTS

During EVLP assessment, EOC-treated lungs showed improvements in physiologic parameters, whereas the control lungs deteriorated. After a total of 48 hours of preservation (36 hours cold + 12 hours normothermic EVLP), transplanted grafts in the treatment group displayed significantly better oxygenation than in the controls (PaO2/FiO2: 437 ± 36 mm Hg vs 343 ± 27 mm Hg, p = 0.041). In addition, the use of EOC led to significantly less edema formation (wet-to-dry ratio: 4.95 ± 0.29 vs 6.05 ± 0.33, p = 0.026), less apoptotic cell death (p = 0.041), improved tight junction preservation (p = 0.002), and lower levels of circulating IL-6 within recipient plasma (p = 0.004) compared with non-use of EOC in the control group after transplantation.

CONCLUSION

The use of an EOC during an extended pulmonary preservation period led to significantly superior early post-transplant lung function.

Relaxin Positively Influences Ischemia-Reperfusion Injury in Solid Organ Transplantation: A Comprehensive Review

In recent decades, solid organ transplantation (SOT) has increased the survival and quality of life for patients with end-stage organ failure by providing a potentially long-term treatment option. Although the availability of organs for transplantation has increased throughout the years, the demand greatly outweighs the supply. One possible solution for this problem is to extend the potential donor pool by using extended criteria donors. However, organs from such donors are more prone to ischemia reperfusion injury (IRI) resulting in higher rates of delayed graft function, acute and chronic graft rejection and worse overall SOT outcomes. This can be overcome by further investigating donor preconditioning strategies, graft perfusion and storage and by finding novel therapeutic agents that could reduce IRI. relaxin (RLX) is a peptide hormone with antifibrotic, antioxidant, anti-inflammatory and cytoprotective properties. The main research until now focused on heart failure; however, several preclinical studies showed its potentials for reducing IRI in SOT. The aim of this comprehensive review is to overview currently available literature on the possible role of RLX in reducing IRI and its positive impact on SOT.

Risk factors and outcome of primary graft dysfunction after lung transplantation in Korea

BACKGROUND

Primary graft dysfunction (PGD) is a severe, acute and post-transplantation lung injury associated with early morbidity and mortality. We aimed to identify clinical risk factors for PGD, as well as the outcome of PGD after lung transplantation in Korea.

METHODS

We retrospectively analyzed lung transplant patients in a South Korean Hospital. The primary outcome was grade 3 PGD, defined according to the International Society for Heart and Lung Transplantation criteria. We compared grade 0-2 PGD group to grade 3 PGD group to identify the risk factors and outcome of grade 3 PGD.

RESULTS

Sixty-one patients were enrolled; 16 (26.2%) developed grade 3 PGD. Univariate analysis revealed higher body mass index (BMI) and history of smoking, extracorporeal membrane oxygenation (ECMO) before transplantation in recipients, and an extended intraoperative ischemic time as risk factors for grade 3 PGD. In multivariate analysis, independent risk factors for PGD were higher BMI in recipients [odds ratio (OR), 1.286; P=0.043] and total intraoperative ischemic time (OR, 1.028; P=0.007). As compared to grade 0-2 PGD, grade 3 PGD was significantly associated with a higher re-operation rate (grade 0-2 PGD vs. grade 3 PGD, 22.2% vs. 50.0%; P=0.036), prolonged ventilator apply (median: 6.0 vs. 14.5 days; P=0.044), a longer intensive care unit stay (median: 9.0 vs. 17.0 days; P=0.041), and a higher rate of renal replacement therapy (RRT) (17.8% vs. 62.5%; P=0.002) after transplantation.

CONCLUSIONS

Patients who developed grade 3 PGD had higher re-operation rate, longer ventilator apply, longer intensive care unit stay, higher rate of RRT, with higher BMI and total intraoperative ischemic time being the significant risk factor. These findings may allow physicians to modify risk factors before development of PGD.

Lung inflation with hydrogen during the cold ischemia phase decreases lung graft injury in rats

Hydrogen has antioxidant and anti-inflammatory effects on lung ischemia-reperfusion injury when it is inhaled by donor or/and recipient. This study examined the effects of lung inflation with 3% hydrogen during the cold ischemia phase on lung graft function in rats. The donor lung was inflated with 3% hydrogen, 40% oxygen, and 57% nitrogen at 5 mL/kg, and the gas was replaced every 20 min during the cold ischemia phase for 2 h. In the control group, the donor lung was inflated with 40% oxygen and 60% nitrogen at 5 mL/kg. The recipient was euthanized 2 h after orthotropic lung transplantation. The hydrogen concentration in the donor lung during the cold ischemia phase was 1.99-3%. The oxygenation indices in the arterial blood and pulmonary vein blood were improved in the hydrogen group. The inflammation response indices, including lung W/D ratio, the myeloperoxidase activity in the grafts, and the levels of IL-8 and TNF-α in serum, were significantly lower in the hydrogen group (5.2 ± 0.8, 0.76 ± 0.32 U/g, 340 ± 84 pg/mL, and 405 ± 115 pg/mL, respectively) than those in the control group (6.5 ± 0.7, 1.1 ± 0.5 U/g, 443 ± 94 pg/mL, and 657 ± 96 pg/mL, respectively (P < 0.05), and the oxidative stress indices, including the superoxide dismutase activity and the level of malonaldehyde in lung grafts were improved after hydrogen application. Furthermore, the lung injury score determined by histopathology, the cell apoptotic index, and the caspase-3 protein expression in lung grafts were decreased after hydrogen treatment, and the static pressure-volume curve of lung graft was improved by hydrogen inflation. In conclusion, lung inflation with 3% hydrogen during the cold ischemia phase alleviated lung graft injury and improved graft function.