Cost effectiveness of commercial portable ex vivo lung perfusion at a low-volume US lung transplant center.

BACKGROUND: Portable ex vivo lung perfusion during lung transplantation is a resource-intensive technology. In light of its increasing use, we evaluated the cost-effectiveness of ex vivo lung perfusion at a low-volume lung transplant center in the USA. METHODS: Patients listed for lung transplantation (2015-2021) in the United Network for Organ Sharing database were included. Quality-of-life was approximated by Karnofsky Performance Status scores 1-year post-transplant. Total transplantation encounter and 1-year follow-up costs accrued by our academic center for patients listed from 2018 to 2021 were obtained. Cost-effectiveness was calculated by evaluating the number of patients attaining various Karnofsky scores relative to cost. RESULTS: Of the 13 930 adult patients who underwent lung transplant in the United Network for Organ Sharing database, 13 477 (96.7%) used static cold storage and 453 (3.3%) used ex vivo lung perfusion, compared to 30/58 (51.7%) and 28/58 (48.3%), respectively, at our center. Compared to static cold storage, median total costs at 1 year were higher for ex vivo lung perfusion ($918 000 vs. $516 000; p = 0.007) along with the cost of living 1 year with a Karnofsky functional status of 100 after transplant ($1 290 000 vs. $841 000). In simulated scenarios, each Karnofsky-adjusted life year gained by ex vivo lung perfusion was 1.00-1.72 times more expensive. CONCLUSIONS: Portable ex vivo lung perfusion is not currently cost-effective at a low-volume transplant centers in the USA, being 1.53 times more expensive per Karnofsky-adjusted life year. Improving donor lung and/or recipient biology during ex vivo lung perfusion may improve its utility for routine transplantation.

Use of a Novel Buffered Hypertonic Saline Solution for Fluid Replacement and Resuscitation During Spinal Surgery in Adolescents.

Background: During major orthopedic procedures, such as posterior spinal fusion (PSF), isotonic fluids, colloids, starches, or gelatins are commonly used to replace the preoperative fluid deficit and provide ongoing fluid resuscitation. Given recent concerns regarding the potential adverse physiologic effects of albumin solutions, we have modified our intraoperative practice to include the use of a novel 2% buffered hypertonic saline solution during major orthopedic procedures. We present our preliminary clinical experience with this novel fluid for intraoperative resuscitation and its impact on limiting the use of 5% albumin. Methods: A retrospective review was performed to identify patients who received 2% buffered hypertonic saline during PSF. The intraoperative course of these patients was compared to case-matched control patients who received standard care with isotonic fluids plus 5% albumin as an adjunct for intravascular resuscitation. Results: The study cohort included 23 patients who received 2% buffered hypertonic saline and 25 in the case-matched control group. There was no difference in the volume of intraoperative isotonic crystalloid fluids, estimated blood loss, and urine output between the two groups. In the control cohort, 19 of 25 patients (76%) received 5% albumin compared to only six of 23 patients (26%, P = 0.0005) in the 2% buffered hypertonic saline group. The final pH was higher in the patients that received 2% buffered hypertonic saline than in the control group (7.40 ± 0.03 versus 7.36 ± 0.06, P = 0.0131). Additionally, the starting and final serum sodium values were higher in the patients that received 2% buffered hypertonic saline, although no difference was noted in the mean change from the starting value (average increase of 2 mEq/L in both groups). Conclusion: Use of a novel 2% buffered hypertonic saline solution for intraoperative resuscitation during major orthopedic procedures decreases the need for 5% albumin while avoiding the development of hyperchloremic metabolic acidosis which may occur with standard sodium chloride solutions.

Factors Associated with Health-Related Quality of Life in Lung Transplant Candidates and Recipients.

OBJECTIVES: Health-related quality of life has been well studied across transplantation fields, but factors associated with lung transplant preoperative and postoperative quality of life remain unknown. Here, we determine factors associated with health-related quality of life in lung transplant candidates and recipients to identify patients at risk of lower health-related quality of life. MATERIALS AND METHODS: From January 2021 to May 2022, health-related quality of life was measured in candidates and recipients using the RAND 36-Item Short Form Health Survey questionnaire. We reviewed demographic parameters and clinical information and scored frailty according to the modified 5-item frailty index. We performed Fisher exact test and the Pearson chi-square test and used linear regression models to determine covariate associations on physical component summary, mental component summary, and self-reported health scores (α = 0.05). RESULTS: Eleven candidates and 17 recipients comp-leted the survey. Compared with candidates, transplant recipients reported significantly higher scores in 4 of the 8 health domains and in the physical component summary (P < .01), mental component summary (P = .05), and self-reported health score (P < .01). In candidates, higher body mass index and higher modified 5-item frailty index scores were negatively associated with the physical component summary and mental component summary, respec-tively (P < .05). In recipients, higher body mass index and higher lung allocation scores were associated with lower values for the physical component summary (-2.29; P < .05) and self-reported health score (-0.33; P < .05), respectively. CONCLUSIONS: Body mass index, the modified 5-item frailty index, and the lung allocation score were significantly associated with health-related quality of life in lung transplant recipients. Future interventions should target these modifiable associations to maximize candidate and recipient health-related quality of life.

Tissue libraries enable rapid determination of conditions that preserve antibody labeling in cleared mouse and human tissue.

Difficulty achieving complete, specific, and homogenous staining is a major bottleneck preventing the widespread use of tissue clearing techniques to image large volumes of human tissue. In this manuscript, we describe a procedure to rapidly design immunostaining protocols for antibody labeling of cleared brain tissue. We prepared libraries of 0.5-1.0 mm thick tissue sections that are fixed, pre-treated, and cleared via similar, but different procedures to optimize staining conditions for a panel of antibodies. Results from a library of mouse tissue correlate well with results from a similarly prepared library of human brain tissue, suggesting mouse tissue is an adequate substitute for protocol optimization. These data show that procedural differences do not influence every antibody-antigen pair in the same way, and minor changes can have deleterious effects, therefore, optimization should be conducted for each target. The approach outlined here will help guide researchers to successfully label a variety of targets, thus removing a major hurdle to accessing the rich 3D information available in large, cleared human tissue volumes.

The Effect of Normothermic Machine Perfusion on the Immune Profile of Donor Liver.

Background: Normothermic machine perfusion (NMP) allows viability assessment and potential resuscitation of donor livers prior to transplantation. The immunological effect of NMP on liver allografts is undetermined, with potential implications on allograft function, rejection outcomes and overall survival. In this study we define the changes in immune profile of human livers during NMP. Methods: Six human livers were placed on a NMP device. Tissue and perfusate samples were obtained during cold storage prior to perfusion and at 1, 3, and 6 hours of perfusion. Flow cytometry, immunohistochemistry, and bead-based immunoassays were used to measure leukocyte composition and cytokines in the perfusate and within the liver tissue. Mean values between baseline and time points were compared by Student's t-test. Results: Within circulating perfusate, significantly increased frequencies of CD4 T cells, B cells and eosinophils were detectable by 1 hour of NMP and continued to increase at 6 hours of perfusion. On the other hand, NK cell frequency significantly decreased by 1 hour of NMP and remained decreased for the duration of perfusion. Within the liver tissue there was significantly increased B cell frequency but decreased neutrophils detectable at 6 hours of NMP. A transient decrease in intermediate monocyte frequency was detectable in liver tissue during the middle of the perfusion run. Overall, no significant differences were detectable in tissue resident T regulatory cells during NMP. Significantly increased levels of pro-inflammatory and anti-inflammatory cytokines were seen following initiation of NMP that continued to rise throughout duration of perfusion. Conclusions: Time-dependent dynamic changes are seen in individual leukocyte cell-types within both perfusate and tissue compartments of donor livers during NMP. This suggests a potential role of NMP in altering the immunogenicity of donor livers prior to transplant. These data also provide insights for future work to recondition the intrinsic immune profile of donor livers during NMP prior to transplantation.

Donor leukocyte trafficking during human ex vivo lung perfusion.

BACKGROUND: Ex vivo lung perfusion (EVLP) is used to assess and preserve lungs prior to transplantation. However, its inherent immunomodulatory effects are not completely understood. We examine perfusate and tissue compartments to determine the change in immune cell composition in human lungs maintained on EVLP. METHODS: Six human lungs unsuitable for transplantation underwent EVLP. Tissue and perfusate samples were obtained during cold storage and at 1-, 3- and 6-h during perfusion. Flow cytometry, immunohistochemistry, and bead-based immunoassays were used to measure leukocyte composition and cytokines. Mean values between baseline and time points were compared by Student's t test. RESULTS: During the 1st hour of perfusion, perfusate neutrophils increased (+22.2 ± 13.5%, p < 0.05), monocytes decreased (-77.5 ± 8.6%, p < 0.01) and NK cells decreased (-61.5 ± 22.6%, p < 0.01) compared to cold storage. In contrast, tissue neutrophils decreased (-22.1 ± 12.2%, p < 0.05) with no change in monocytes and NK cells. By 6 h, perfusate neutrophils, NK cells, and tissue neutrophils were similar to baseline. Perfusate monocytes remained decreased, while tissue monocytes remained unchanged. There was no significant change in B cells or T cell subsets. Pro-inflammatory cytokines (IL-1b, G-CSF, IFN-gamma, CXCL2, CXCL1 granzyme A, and granzyme B) and lymphocyte activating cytokines (IL-2, IL-4, IL-6, IL-8) increased during perfusion. CONCLUSIONS: Early mobilization of innate immune cells occurs in both perfusate and tissue compartments during EVLP, with neutrophils and NK cells returning to baseline and monocytes remaining depleted after 6 h. The immunomodulatory effect of EVLP may provide a therapeutic window to decrease the immunogenicity of lungs prior to transplantation.

Pulmonary Parenchymal Changes in COVID-19 Survivors.

BACKGROUND: As the COVID-19 pandemic moves into the survivorship phase, questions regarding long-term lung damage remain unanswered. Previous histopathologic studies are limited to autopsy reports. We studied lung specimens from COVID-19 survivors who underwent elective lung resections to determine whether postacute histopathologic changes are present. METHODS: This multicenter observational study included 11 adult COVID-19 survivors who had recovered but subsequently underwent unrelated elective lung resection for indeterminate lung nodules or lung cancer. We compared these against an age- and procedure-matched control group who never contracted COVID-19 (n = 5) and an end-stage COVID-19 group (n = 3). A blinded pulmonary pathologist examined the lung parenchyma focusing on 4 compartments: airways, alveoli, interstitium, and vasculature. RESULTS: Elective lung resection was performed in 11 COVID-19 survivors with asymptomatic (n = 4), moderate (n = 4), and severe (n = 3) COVID-19 infections at a median 68.5 days (range 24-142 days) after the COVID-19 diagnosis. The most common operation was lobectomy (75%). Histopathologic examination identified no differences between the lung parenchyma of COVID-19 survivors and controls across all compartments examined. Conversely, patients in the end-stage COVID-19 group showed fibrotic diffuse alveolar damage with intra-alveolar macrophages, organizing pneumonia, and focal interstitial emphysema. CONCLUSIONS: In this study to examine the lung parenchyma of COVID-19 survivors, we did not find distinct postacute histopathologic changes to suggest permanent pulmonary damage. These results are reassuring for COVID-19 survivors who recover and become asymptomatic.

A Deep Learning Approach to Diagnostic Classification of Prostate Cancer Using Pathology-Radiology Fusion.

BACKGROUND: A definitive diagnosis of prostate cancer requires a biopsy to obtain tissue for pathologic analysis, but this is an invasive procedure and is associated with complications. PURPOSE: To develop an artificial intelligence (AI)-based model (named AI-biopsy) for the early diagnosis of prostate cancer using magnetic resonance (MR) images labeled with histopathology information. STUDY TYPE: Retrospective. POPULATION: Magnetic resonance imaging (MRI) data sets from 400 patients with suspected prostate cancer and with histological data (228 acquired in-house and 172 from external publicly available databases). FIELD STRENGTH/SEQUENCE: 1.5 to 3.0 Tesla, T2-weighted image pulse sequences. ASSESSMENT: MR images reviewed and selected by two radiologists (with 6 and 17 years of experience). The patient images were labeled with prostate biopsy including Gleason Score (6 to 10) or Grade Group (1 to 5) and reviewed by one pathologist (with 15 years of experience). Deep learning models were developed to distinguish 1) benign from cancerous tumor and 2) high-risk tumor from low-risk tumor. STATISTICAL TESTS: To evaluate our models, we calculated negative predictive value, positive predictive value, specificity, sensitivity, and accuracy. We also calculated areas under the receiver operating characteristic (ROC) curves (AUCs) and Cohen's kappa. RESULTS: Our computational method (https://github.com/ih-lab/AI-biopsy) achieved AUCs of 0.89 (95% confidence interval [CI]: [0.86-0.92]) and 0.78 (95% CI: [0.74-0.82]) to classify cancer vs. benign and high- vs. low-risk of prostate disease, respectively. DATA CONCLUSION: AI-biopsy provided a data-driven and reproducible way to assess cancer risk from MR images and a personalized strategy to potentially reduce the number of unnecessary biopsies. AI-biopsy highlighted the regions of MR images that contained the predictive features the algorithm used for diagnosis using the class activation map method. It is a fully automatic method with a drag-and-drop web interface (https://ai-biopsy.eipm-research.org) that allows radiologists to review AI-assessed MR images in real time. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY STAGE: 2.

Neuronal death in pneumococcal meningitis is triggered by pneumolysin and RrgA interactions with ß-actin.

Neuronal damage is a major consequence of bacterial meningitis, but little is known about mechanisms of bacterial interaction with neurons leading to neuronal cell death. Streptococcus pneumoniae (pneumococcus) is a leading cause of bacterial meningitis and many survivors develop neurological sequelae after the acute infection has resolved, possibly due to neuronal damage. Here, we studied mechanisms for pneumococcal interactions with neurons. Using human primary neurons, pull-down experiments and mass spectrometry, we show that pneumococci interact with the cytoskeleton protein ß-actin through the pilus-1 adhesin RrgA and the cytotoxin pneumolysin (Ply), thereby promoting adhesion and invasion of neurons, and neuronal death. Using our bacteremia-derived meningitis mouse model, we observe that RrgA- and Ply-expressing pneumococci co-localize with neuronal ß-actin. Using purified proteins, we show that Ply, through its cholesterol-binding domain 4, interacts with the neuronal plasma membrane, thereby increasing the exposure on the outer surface of ß-actin filaments, leading to more ß-actin binding sites available for RrgA binding, and thus enhanced pneumococcal interactions with neurons. Pneumococcal infection promotes neuronal death possibly due to increased intracellular Ca2+ levels depending on presence of Ply, as well as on actin cytoskeleton disassembly. STED super-resolution microscopy showed disruption of ß-actin filaments in neurons infected with pneumococci expressing RrgA and Ply. Finally, neuronal death caused by pneumococcal infection could be inhibited using antibodies against ß-actin. The generated data potentially helps explaining mechanisms for why pneumococci frequently cause neurological sequelae.