BACKGROUND: Pneumatosis intestinalis is a radiological finding characterized by the presence of gas in the bowel wall that is associated with multiple entities. Our aim is to know its incidence in lung transplant patients, its physiopathology and its clinical relevance.
METHODS: A search of patients with pneumatosis intestinalis was performed in the database of the Lung Transplant Unit of our hospital. The presence of pneumatosis after transplantation was confirmed in all of them and relevant demographic, clinical and imaging variables were collected to evaluate its association and clinical expression, as well as the therapeutic approach after the findings.
RESULTS: The incidence of pneumatosis intestinalis after lung transplantation in our center was 3.1% (17/546), developing between 9 and 1270 days after transplantation (mean, 198 days; median 68 days). Most of the patients were asymptomatic or with mild symptoms, without any major analytical alterations, and with a cystic and expansive radiological appearance. Pneumoperitoneum was associated in 70% of the patients (12/17). Conservative treatment was chosen in all cases. The mean time to resolution was 389 days.
CONCLUSIONS: Pneumatosis intestinalis in lung transplant patients is a rare complication of uncertain origin, which can appear for a very long period of time after transplantation. It has little clinical relevance and can be managed without other diagnostic or therapeutic interventions.

BACKGROUND: In lung transplantation (LT), the length of ischemia time is controversial as it was arbitrarily stablished. We ought to explore the impact of extended cold-ischemia time (CIT) on ischemia-reperfusion injury in an experimental model.
METHODS: Experimental, randomized pilot trial of parallel groups and final blind analysis using a swine model of LT. Donor animals (n=8) were submitted to organ procurement. Lungs were subjected to 6h (n=4) or 12h (n=4) aerobic hypothermic preservation. The left lung was transplanted and re-perfused for 4h. Lung biopsies were obtained at (i) the beginning of CIT, (ii) the end of CIT, (iii) 30min after reperfusion, and (iv) 4h after reperfusion. Lung-grafts were histologically assessed by microscopic lung injury score and wet-to-dry ratio. Inflammatory response was measured by determination of inflammatory cytokines. Caspase-3 activity was determined as apoptosis marker.
RESULTS: We observed no differences on lung injury score or wet-to-dry ratio any given time between lungs subjected to 6h-CIT or 12h-CIT. IL-1β and IL6 showed an upward trend during reperfusion in both groups. TNF-α was peaked within 30min of reperfusion. IFN-γ was hardly detected. Caspase-3 immunoexpression was graded semiquantitatively by the percentage of stained cells. Twenty percent of apoptotic cells were observed 30min after reperfusion.
CONCLUSIONS: We observed that 6 and 12h of CIT were equivalent in terms of microscopic lung injury, inflammatory profile and apoptosis in a LT swine model. The extent of lung injury measured by microscopic lung injury score, proinflammatory cytokines and caspase-3 determination was mild.

OBJECTIVE: Lung transplantation (LT) for pulmonary fibrosis is related to higher mortality than other transplant indications. We aim to assess whether the amount of anterior mediastinal fat (AMF) was associated to early and long-term outcomes in fibrotic patients undergoing LT.
METHODS: Retrospective analysis of 92 consecutive single lung transplants (SLT) for pulmonary fibrosis over a 10-year period. AMF dimensions were measured on preoperative CT-scan: anteroposterior axis (AP), transverse axis (T), and height (H). AMF volumes (V) were calculated by the formula: AP×T×H×3.14/6. According to the radiological AMF dimensions, patients were distributed into two groups: low-AMF (V<20cm3) and high-AMF (V>20cm3), and early and long-term outcomes were compared by univariable and multivariable analyses.
RESULTS: There were 92 SLT: 73M/19F, 53±11 [14-68] years old. 30-Day mortality (low-AMF vs. high-AMF): 5 (5.4%) vs. 15 (16.3%), p=0.014. Patients developing primary graft dysfunction within 72h post-transplant, and those dying within 30 days post-transplant presented higher AMF volumes: 21.1±19.8 vs. 43.3±24.7cm3 (p=0.03) and 24.4±24.2 vs. 56.9±63.6cm3 (p<0.01) respectively. Overall survival (low-AMF vs. high-AMF) (1, 3, and 5 years): 85%, 81%, 78% vs. 55%, 40%, 33% (p<0.001). Factors predicting 30-day mortality were: BMI (HR=0.77, p=0.011), AMF volume (HR=1.04, p=0.018), CPB (HR=1.42, p=0.002), ischaemic time (HR=1.01, p=0.009). Factors predicting survival were: AMF volume (HR=1.02, p<0.001), CPB (HR=3.17, p=0.003), ischaemic time (HR=1.01, p=0.001).
CONCLUSIONS: Preoperative radiological assessment of mediastinal fat dimensions and volumes may be a useful tool to identify fibrotic patients at higher risk of mortality after single lung transplantation.

BACKGROUND: Scedosporium species and Lomentospora prolificans (Sc/Lp) are emerging molds that cause invasive disease associated with a high mortality rate. After Aspergillus, these molds are the second filamentous fungi recovered in lung transplant (LT) recipients.
OBJECTIVE: Our objective was to evaluate the incidence, risk factors and outcome of Sc/Lp infections in LT recipients at a tertiary care hospital with a national reference LT program.
METHODS: A nine-year retrospective study was conducted.
RESULTS: During this period, 395 LT were performed. Positive cultures for Sc/Lp were obtained from twenty-one LT recipients. Twelve patients (incidence 3.04%) developed invasive scedosporiosis (IS). In 66.7% of the patients with IS the invasive infection was defined as a breakthrough one. The main sites of infection were lungs and paranasal sinuses. Most of the patients received combination antifungal therapy. The IS crude mortality rate after 30 days was 16.7%, and 33.3% after a year.
CONCLUSIONS: Our study highlights improved survival rates associated with combination antifungal therapy in LT recipients and underlines the risk of breakthrough infections in patients with allograft dysfunction on nebulized lipidic amphotericin B prophylaxis. In addition to pretransplant colonization, acute or chronic organ dysfunctions seem to be the main risk factors for IS.

BACKGROUND: In lung transplantation (LT), the length of ischemia time is controversial as it was arbitrarily stablished. We ought to explore the impact of extended cold-ischemia time (CIT) on ischemia-reperfusion injury in an experimental model.
METHODS: Experimental, randomized pilot trial of parallel groups and final blind analysis using a swine model of LT. Donor animals (n=8) were submitted to organ procurement. Lungs were subjected to 6h (n=4) or 12h (n=4) aerobic hypothermic preservation. The left lung was transplanted and re-perfused for 4h. Lung biopsies were obtained at (i) the beginning of CIT, (ii) the end of CIT, (iii) 30min after reperfusion, and (iv) 4h after reperfusion. Lung-grafts were histologically assessed by microscopic lung injury score and wet-to-dry ratio. Inflammatory response was measured by determination of inflammatory cytokines. Caspase-3 activity was determined as apoptosis marker.
RESULTS: We observed no differences on lung injury score or wet-to-dry ratio any given time between lungs subjected to 6h-CIT or 12h-CIT. IL-1β and IL6 showed an upward trend during reperfusion in both groups. TNF-α was peaked within 30min of reperfusion. IFN-γ was hardly detected. Caspase-3 immunoexpression was graded semiquantitatively by the percentage of stained cells. Twenty percent of apoptotic cells were observed 30min after reperfusion.
CONCLUSIONS: We observed that 6 and 12h of CIT were equivalent in terms of microscopic lung injury, inflammatory profile and apoptosis in a LT swine model. The extent of lung injury measured by microscopic lung injury score, proinflammatory cytokines and caspase-3 determination was mild.

Tuberculosis (TB) represents a diagnostic and therapeutic challenge for solid organ transplant recipients, particularly after lung transplant (LT). Our aim was to determine the impact of TB in LT patients in Spain, considering prevalence, clinical presentation, prevention and therapeutic management. In addition, differences in outcome between rifampicin (RIF) versus non-RIF containing regimens were analyzed.
Multicenter, observational retrospective study, including all cases of TB diagnosed in recipients after LT, in five pulmonary transplant units in Spain, between January 1990 and December 2017.
Among 2962 LT recipients, 45 cases of TB were diagnosed, resulting in a prevalence of 1.52%. Most of them (88.89%) were diagnosed during the first year posttransplantation, 86.67% with pulmonary presentation. Screening for latent TB infection (LTBI) was done in 36 of the 45 patients and LTBI was detected pretransplant in 12 (33.33%). Less than half of the patients with disease (42.22%) received rifampicin (RIF). Lower probability of TB worsening was found in RIF-containing regimens (p=0.049), as well as longer survival (p=0.001). RIF use was not associated with an increased risk in rejection (p=0.99), but doses of calcineurin inhibitors (CNI) had to be raised an average of 215%.
Risk of TB after LT was lower in our series than previously reported. TB should be searched during the first year posttransplant in patients with TB risk factors. Pulmonary presentation was predominant. More sensitive algorithms for detecting LTBI before LT are crucial. It is reasonable to use RIF-containing regimens over non-RIF regimens based on the tendency toward better outcome in our series. RIF regimen requires close monitoring of CNI trough level for 2-3 weeks, until stability is achieved.

Lung biofabrication is a new tissue engineering and regenerative development aimed at providing organs for potential use in transplantation. Lung biofabrication is based on seeding cells into an acellular organ scaffold and on culturing them in an especial purpose bioreactor. The acellular lung scaffold is obtained by decellularizing a non-transplantable donor lung by means of conventional procedures based on application of physical, enzymatic and detergent agents. To avoid immune recipient\'s rejection of the transplanted bioengineered lung, autologous bone marrow/adipose tissue-derived mesenchymal stem cells, lung progenitor cells or induced pluripotent stem cells are used for biofabricating the bioengineered lung. The bioreactor applies circulatory perfusion and mechanical ventilation with physiological parameters to the lung during biofabrication. These physical stimuli to the organ are translated into the stem cell local microenvironment - e.g. shear stress and cyclic stretch - so that cells sense the physiological conditions in normally functioning mature lungs. After seminal proof of concept in a rodent model was published in 2010, the hypothesis that lungs can be biofabricated is accepted and intense research efforts are being devoted to the topic. The current experimental evidence obtained so far in animal tests and in ex vivo human bioengineered lungs suggests that the date of first clinical tests, although not immediate, is coming. Lung bioengineering is a disrupting concept that poses a challenge for improving our basic science knowledge and is also an opportunity for facilitating lung transplantation in future clinical translation.