In Vitro Fermentation of NUTRIOSE® FB06, a wheat dextrin soluble fibre, in a continuous culture human colonic model system

Wheat dextrin soluble fibre may have metabolic and health benefits, potentially acting via mechanisms governed by the selective modulation of the human gut microbiota. Our aim was to examine the impact of wheat dextrin on the composition and metabolic activity of the gut microbiota. We used a validated in vitro three-stage continuous culture human colonic model (gut model) system comprised of vessels simulating anatomical regions of the human colon. To mimic human ingestion, 7 g of wheat dextrin (NUTRIOSE® FB06) was administered to three gut models, twice daily at 10.00 and 15.00, for a total of 18 days. Samples were collected and analysed for microbial composition and organic acid concentrations by 16S rRNA-based fluorescence in situ hybridisation and gas chromatography approaches, respectively. Wheat dextrin mediated a significant increase in total bacteria in vessels simulating the transverse and distal colon, and a significant increase in key butyrate-producing bacteria Clostridium cluster XIVa and Roseburia genus in all vessels of the gut model. The production of principal short-chain fatty acids, acetate, propionate and butyrate, which have been purported to have protective, trophic and metabolic host benefits, were increased. Specifically, wheat dextrin fermentation had a significant butyrogenic effect in all vessels of the gut model and significantly increased production of acetate (vessels 2 and 3) and propionate (vessel 3), simulating the transverse and distal regions of the human colon, respectively. In conclusion, wheat dextrin NUTRIOSE® FB06 is selectively fermented in vitro by Clostridium cluster XIVa and Roseburia genus and beneficially alters the metabolic profile of the human gut microbiota

Implications of the ISHLT 2005 and 2016 PGD Grading System.

PURPOSE: In 2005, an ISHLT working group proposed a grading system for primary graft dysfunction (PGD) following lung transplantation (LTx), based on oxygenation (P/F) and chest X-ray. This system was revised in 2016. The aim of this study is to compare the impact of the 2016 revised versus the original 2005 grading system on PGD prevalence and early post-LTx outcome. METHODS: All patients receiving double LTx at our institution between 12/2016 and 01/2018 (n=75) were retrospectively studied. P/F ratios were calculated and X-rays were scored by two experts blinded for clinical information at time (T) points 0, 24, 48, and 72 hours. PGD grading was determined separately according to 2005 and 2016 PGD definition. When multiple P/F ratios were available, the lowest P/F was used. RESULTS: Results are visualized in figure 1. PGD distribution at T0, T24, T72 differed between 2005 and 2016 (p<0.001; p=0.005; p=0.05), but not at 48h (p=0.19). PGD-3 incidence at T0 (48%), T24 (29%), T48 (17%) was higher according to the 2005 score compared to 2016 score (31%, 25%, and 16%, respectively). In contrast, PGD-3 at T72 was lower according to the 2005 score (12%) compared to the 2016 score (16%). Time to extubation (p=0.93), ICU stay (p=0.33) and hospital stay (p=0.43) of patients with PGD-3 at any time (T0 - T72) hours did not differ according the grading system (figure 1, down). CONCLUSION: PGD grading differs between the original and the new PGD scoring system with a higher proportion of lower grades according to the 2016 definition at early time points. This might be explained by the more prominent role of chest radiography in the 2016 classification for PGD 0 regardless of the P/F ratio. On the other hand, according to the 2016 classification system, extubated patients are no longer automatically scored as PGD-0 or PGD-1, which might explain the higher proportion of PGD3 at T72. Early outcome was comparable between the two systems when patients suffered from PGD3 at any time point after transplantation. The impact of PGD grading on long-term outcome should be further investigated.status: publishe

How long can we preserve the pulmonary graft inside the nonheart-beating donor?

Background. The use of lungs from nonheart-beating donors (NHBD) might significantly alleviate the organ shortage. Extending the preharvest interval in NHBD would facilitate distant organ retrieval. We hypothesized that prolonged topical cooling inside NHBD after 60 minutes of initial warm ischemia would not affect the pulmonary graft. Methods. Domestic pigs were anesthetized and divided into three groups (n = 6 in each group). In the control group (HBD), lungs were flushed, explanted, and further stored in low potassium dextran solution (4 degreesC) for 4 hours. In the two study groups pigs were sacrificed by myocardial fibrillation and left untouched for 1 hour. Chest drains were then inserted for topical lung cooling (6 degreesC) for 3 hours (NHBD-TC3) or 6 hours (NHBD-TC6). The left lung in all groups was then prepared for evaluation. In an isolated circuit lungs were ventilated and reperfused through the pulmonary artery. Hemodynamic, aerodynamic, and oxygenation variables were measured 35 minutes after onset of controlled reperfusion. Wet-to-dry weight ratio was calculated. Results. No significant differences were observed among the three groups in pulmonary vascular resistance (p = 0.38), mean airway pressure (p = 0.39), oxygenation index (p = 0.62), and wet-to-dry weight ratio (p = 0.09). Conclusions. These data confirm that 1 hour of warm ischemia does not affect the pulmonary graft from NHBD compared with HBD. The preharvest interval can be safely extended up to 7 hours postmortem by additional topical cooling of the graft inside the cadaver. This technique may facilitate distant organ retrieval in NHBD. (C) 2004 by The Society of Thoracic Surgeons

The Value of Ex Situ CT Imaging of Donor Lungs Prior to Transplantation.

PURPOSE: Donor shortage remains a major obstacle associated with considerable mortality in patients waiting for lung transplantation (LTx). Objective donor lung assessment is crucial to obtain sufficient grafts of acceptable quality. We hypothesized that out of body chest CT may be an innovative way to assess grafts prior to LTx. Therefore, this study prospectively investigated the value of CT scan of donor lungs prior to LTx. METHODS: Between 12/2016 and 01/2018, all potential donor lungs were inspected in-situ, recovered and ex situ CT scanned during standard cold preservation. The transplant team and radiologist were blinded for the CT scan, which thus did not change the decision to transplant. CTs were scored for CT abnormalities and were compared between transplanted (Tx) and non-Tx grafts. In addition, CT of Tx grafts were compared between recipients developing PGD3 within 72 h ('PGD3') and recipients who did not ('No PGD3'). RESULTS: In total, 75 lungs were transplanted and 25 were not transplanted, of which 19 were declined for poor graft quality and 6 for extrapulmonary malignancies or logistics. CT abnormalities (CSL, GGO, EMPHY) differed between Tx and non-Tx grafts (Figure 1A). In lungs declined for poor graft quality (n=19), the reason for decline was confirmed in 13 lungs, however 4 lungs had only limited CT abnormalities present. In 2 out of 7 lungs declined at retrieval for clinical suspicion of emphysema, no emphysema was present on CT. In addition, CT abnormalities (CSL, RET/IST) of Tx grafts also significantly differed between recipients with PGD 3 and without PGD 3 (Fig 1B). CONCLUSION: Ex situ CT imaging of donor grafts during preservation is feasible and demonstrated significant differences between Tx and non-Tx grafts. Also grafts of patients with or without PGD3 differed in CT parameters. CT imaging could not confirm the reason for decline in 6 lungs, which might indicate an undisclosed graft potential and a role of CT imaging in donor assessment. The prognostic value of CT parameters on long-term outcomes remains elusive.status: publishe

Blood Eosinophilia Predicts Poor Outcome in Lung Transplant Recipients

PURPOSE: Eosinophils are associated with the onset of chronic respiratory diseases like asthma and COPD. In lung transplantation, patients with increased bronchoalveolar lavage eosinophils demonstrated a worse chronic lung allograft dysfunction (CLAD)-free survival and overall survival. We investigated the association between blood eosinophilia, graft survival and CLAD-free survival after lung transplantation. METHODS: A retrospective analysis was performed including all transplanted patients within our center between 2011 and 2016 (n=376). Blood eosinophils were measured as part of the routine clinical follow-up including all measurements prior to 01/06/2019. A ROC analysis was performed to define cut-offs for blood eosinophilia and patients were subsequently divided in those with high blood eosinophilia vs. those with lower eosinophilia based on the defined cut-off. All patients received oral steroids as part of their standard immunosuppressive drug regimen. RESULTS: ROC analysis revealed that the optimal threshold for blood eosinophilia is >7.85% (p=0.0026) for overall survival and >7.75% (p=0.001) for CLAD-free survival. Using a threshold of >8%, 112 patients had high blood eosinophilia and 264 had low eosinophilia (16 patients developed high eosinophilia after CLAD). Patients with blood eosinophilia >8% demonstrated worse graft survival (p=0.004) and CLAD-free survival (p=0.0076) compared to those with lower blood eosinophilia. Within the high eosinophilia group, 65 (58%) patients were diagnosed with CLAD, of which 42 (37.5%) patients had BOS and 23 (20.5%) had RAS. In the group with lower eosinophilia, 80 (30.3%) patients developed CLAD with 71 (26.9%) BOS and 9 (3.4%) RAS (p8%) demonstrate inferior graft survival and CLAD-free survival, specifically RAS. These findings require further research and may lead to the development of an easy to use, non-invasive marker for poor transplant outcome.status: publishe

A systematic review and meta-analyses of regional perfusion in donation after circulatory death solid organ transplantation

In donation after circulatory death (DCD), (thoraco)abdominal regional perfusion (RP) restores circulation to a region of the body following death declaration. We systematically reviewed outcomes of solid organ transplantation after RP by searching PubMed, Embase, and Cochrane libraries. Eighty-eight articles reporting on outcomes of liver, kidney, pancreas, heart, and lung transplants or donor/organ utilization were identified. Meta-analyses were conducted when possible. Methodological quality was assessed using National Institutes of Health (NIH)-scoring tools. Case reports (13/88), case series (44/88), retrospective cohort studies (35/88), retrospective matched cohort studies (5/88), and case-control studies (2/88) were identified, with overall fair quality. As blood viscosity and rheology change below 20 °C, studies were grouped as hypothermic (HRP, ≤20 °C) or normothermic (NRP, >20 °C) regional perfusion. Data demonstrate that RP is a safe alternative to in situ cold preservation (ISP) in uncontrolled and controlled DCDs. The scarce HRP data are from before 2005. NRP appears to reduce post-transplant complications, especially biliary complications in controlled DCD livers, compared with ISP. Comparisons for kidney and pancreas with ISP are needed but there is no evidence that NRP is detrimental. Additional data on NRP in thoracic organs are needed. Whether RP increases donor or organ utilization needs further research

Histopathologic and Radiologic Assessment of Unused Donor Lungs: When to Decline or Not?

PURPOSE: Donor organ shortage, in combination with a 70% decline rate of offered donor lungs, results in significant wait list mortality and time with poor quality of life. Assessing donor lungs for transplant suitability is based on donors' history, gas exchange, chest X-ray, bronchoscopy, and in situ visual inspection; but donor lung acceptance remains subjective. We performed an in depth histopathologic and radiologic assessment of retrieved but unused donor lungs. METHODS: We assessed 62 donor lungs not used for transplantation for various reasons between 2010 and 2019. These lungs were air-inflated, frozen, scanned with computed tomography, systematically sampled on 4 different locations, assessed macroscopically and microscopically by two experienced lung pathologists and by an experienced thoracic radiologist, all blinded for the reason of decline. RESULTS: Reasons for non-use are summarized in the figure. Thirty-nine (63%) lungs were not used for allograft-related reasons. In 13/39 (33%) lungs, the reason for decline could not be confirmed by histologic assessment (emboli, n=7; pneumonia, n=3; contusion, n=2; emphysema, n=1), in an additional 8/39 (21%) lungs, histologic abnormalities were only considered focal and mild (emphysema, n=5; pneumonia, n=3). In 16/39 (41%) lungs, radiology could not confirm the reason for decline. Twenty-three (37%) of 62 unused donor lungs were not transplanted due to extra pulmonary causes, of which 3 (13%) lungs displayed severe histologic abnormalities (pneumonia, n=2; emphysema, n=1), in addition to mild emphysema in 9 (39%) lungs and mild bronchopneumonia in 1 lung (4%). Radiology revealed ground-glass opacities in 8/23 (35%) and emphysema in 4/23 (17%) of these donor lungs. CONCLUSION: Histologic and radiologic assessment of unused donor lungs revealed substantial discrepancy with the clinical reason for decline. Prior chest CT imaging and frozen sections in selected cases might contribute to adequate donor assessment and augment current yield of donor lungs.status: publishe

Donation after Euthanasia (DCD-V) Results in Excellent Long-Term Outcome after Lung Transplantation, Equal to Donation after Brain Death (DBD) and Circulatory Death (DCD-III).

PURPOSE: In countries with a legal framework for physician-assisted death, organ donation after euthanasia (DCD-V) can increase the donor pool. DCD-V grafts are characterized by absence of lung injury related to brain-death, intubation and a long agonal phase. We review our experience with LTx after DCD-V and compare outcome with DBD and DCD-III experience in the same era. METHODS: Between 01/2007-09/2019, 797 LTx were performed, of which 158 from DCD donors, including 20 DCD-V {8M/12F; mean age (range): 50 (28-66y)} due to neuromuscular (8) / mental (9) disorder or untreatable pain (3). After the request for euthanasia was granted in accordance with legislation, an explicit wish for organ donation was expressed by the patient and approved by the Institutional Review Board. Euthanasia was carried out in-hospital (local: 4; remote: 16) adjacent to the operating room in absence of the retrieval team. RESULTS: Twenty patients {7M/13F; age: 53y (27-64)} underwent bilateral LTx for emphysema (n=10), pulmonary fibrosis (n=5), cystic fibrosis (n=3, liver transplant in 1) and bronchiolitis obliterans (n=2). Waiting time was 326d (34-662). Agonal phase was short: 3min (0-14). Warm ischemia time between circulatory arrest and flush was 12min (7-21). Intensive care unit and hospital stay were 6d (2-10) and 28d (16-44). Three patients died due to cardiac problem (3mo), haematological disorder (3mo) or aspergillosis (10y). Follow-up was 4y (2mo-10.5y), CLAD occurred in 4. Five-year patient survival for DCD-V was 89%, equaling the DBD {80% (p=0.68)} and DCD-III cohort {81% (p=0.78)}. CLAD-free survival was 66.7%, equal to DBD {68.2% (p=0.68)} and DCD-III {69.9% (p=0.91)}. CONCLUSION: Our series represents the largest LTx experience from DCD-V and demonstrates for the first time that long-term outcome is comparable with DBD and DCD-III. DCD-V can further expand the donor pool in nations with a legal framework for physician-assisted death.status: publishe

Flow Controlled Ventilation during EVLP Improves Oxygenation and Preserves Alveolar Recruitment.

PURPOSE: Ex vivo lung perfusion (EVLP) is considered a useful platform to evaluate, preserve and recondition grafts prior to lung transplantation (LTx). Reducing physical stress due to standard volume-controlled ventilation (VCV), might further prolong EVLP in time and reduce ventilator induced lung injury (VILI). An innovative approach might be the use of flow-controlled ventilation (FCV), a ventilation mode which controls inspiratory and expiratory flow. These properties can reduce atelectrauma and volutrauma related to standard VCV. This is the first study to evaluate the use of FCV during EVLP in a porince model. METHODS: Porcine lungs were mounted on EVLP after 2 hours of warm ischemia and divided into 2 groups (n=7/group). EVLP was maintained for 6 hours and physiological parameters were continuously recorded. In the first group, lungs on EVLP were ventilated standardly (VCV, 7 ml/kg). In the second group, lungs were ventilated using FCV (7ml/kg). After EVLP, W/D ratios were taken of the right lung and the left lung was frozen while inflated in liquid nitrogen vapors and CT scanned. RESULTS: Results are demonstrated in figure 1. Pulmonary vascular resistance (PVR) was comparable between VCV and FCV (p=0.52). FCV significantly increased oxygenation (P/F ratios) (p=0.01), and better maintained dynamic compliance (p=0.03). There was no difference in W/D ratios between the groups (p=0.16). CT density measurements were decreased by FCV (p=0.05). CONCLUSION: FCV is feasible to ventilate pulmonary grafts during EVLP and improves oxygenation. The lower decline in compliance and lower CT density measurements in FCV might indicate a better preservation of alveolar recruitment since extravascular water content (W/D ratio) was similar between both groups. In conclusion, FCV ventilation might reduce injury related to standard volume-controlled ventilation. Using FCV mode during EVLP might stabilize and prolong EVLP time in the future and open the perspective to further actively recondition grafts.status: publishe