Normal brain aging is accompanied by patterns of functional and structural change.Alzheimer's disease (AD), a representative neurodegenerative disease, has been linked to accelerated brain aging at respective age ranges. Here, we developed a deep learning-based brain age prediction model using fluorodeoxyglucose (FDG) PET and structural MRI and tested how the brain age gap relates to degenerative cognitive syndromes including mild cognitive impairment, AD, frontotemporal dementia, and Lewy body dementia. Occlusion analysis, performed to facilitate interpretation of the model, revealed that the model learns an age-and modality-specific pattern of brain aging. The elevated brain age gap in dementia cohorts was highly correlated with the cognitive impairment and AD biomarker. However, regions generating brain age gaps were different for each diagnosis group of which the AD continuum showed similar patterns to normal aging in the CU.

Effective re-endothelialization is critical for the use of decellularized scaffolds for ex vivo lung engineering. Current approaches yield insufficiently re-endothelialized scaffolds that haemorrhage and become thrombogenic upon implantation. Herein, gravity-driven seeding coupled with bioreactor culture facilitated widespread distribution and engraftment of endothelial cells throughout rat lung scaffolds. Initially, human umbilical vein endothelial cells were seeded into the pulmonary artery by either gravity-driven, variable flow perfusion seeding or pump-driven, pulsatile flow perfusion seeding. Gravity seeding evenly distributed cells and supported cell survival and re-lining of the vascular walls while perfusion pump-driven seeding led to increased cell fragmentation and death. Using gravity seeding, rat pulmonary artery endothelial cells and rat pulmonary vein endothelial cells attached in intermediate and large vessels, while rat pulmonary microvascular endothelial cells deposited mostly in microvessels. Combination seeding of these cells led to positive vascular endothelial cadherin staining. In addition, combination seeding improved barrier function as assessed by serum albumin extravasation; however, leakage was observed in the distal portions of the re-endothelialized tissue suggesting that recellularization of the alveoli is necessary to complete barrier function of the capillary-alveolar network. Overall, these data indicate that vascular recellularization of rat lung scaffolds is achieved through gravity seeding. Copyright © 2016 John Wiley & Sons, Ltd.

There are an insufficient number of donor organs available to meet the demand for lung transplantation. This issue could be addressed by regenerating functional tissue from diseased or damaged lungs that would otherwise be deemed unsuitable for transplant. Detergent-mediated whole-lung decellularization produces a threedimensional natural scaffold that can be repopulated with various cell types. In this study, we investigated the decellularization and initial recellularization of diseased lungs using a rat model of monocrotaline-induced pulmonary hypertension (MCT-PHT). Decellularization of control and MCT-PHT Sprague-Dawley rat lungs was accomplished by treating the lungs with a combination of Triton X-100, sodium deoxycholate, NaCl, and DNase. The resulting acellular matrices were characterized by DNA quantification, Western blotting, immunohistochemistry, and proteomic analyses revealing that decellularization was able to remove cells while leaving the extracellular matrix (ECM) components and lung ultrastructure intact. Decellularization significantly reduced DNA content (*30-fold in MCT-PHT lungs and *50-fold in the control lungs) and enriched ECM components ( > 60-fold in both the control and MCT-PHT lungs) while depleting cellular proteins. MicroCT visualization of MCT-PHT rat lungs indicated that the vasculature was narrowed as a result of MCT treatment, and this characteristic was unchanged by decellularization. Mean arterial vessel diameter of representative decellularized MCT-PHT and control scaffolds was estimated to be 0.152 -0.134 mm and 0.247 -0.160 mm, respectively. Decellularized MCT-PHT lung scaffolds supported attachment and survival of rat adipose-derived stem cells (rASCs), seeded into the airspace or the vasculature, for at least 2 weeks. The cells seeded in MCT-PHT lung scaffolds proliferated and underwent apoptosis similar to control scaffolds; however, the initial percentage of apoptotic cells was slightly higher in MCT-PHT lungs (2.79 -2.03% vs. 1.05 -1.02% of airway-seeded rASCs, and 4.47 -1.21% vs. 2.66 -0.10% of vascular seeded rASCs). The ECM of cell-seeded scaffolds showed no signs of degradation by the cells after 14 days in culture. These data suggest that diseased hypertensive lungs can be efficiently decellularized similar to control lungs and have the potential to be recellularized with mesenchymal stem cells with the ultimate goal of generating healthy, functional pulmonary tissue.

Current and future opportunities and challenges with respect to radiology are provided with emphasis on cardiothoracic imaging.

Memory acquisition and synaptic plasticity are accompanied by changes in the intrinsic excitability of CA1 pyramidal neurons. These activity-dependent changes in excitability are mediated by modulation of intrinsic currents which alters the responsiveness of the cell to synaptic inputs. The afterhyperpolarization (AHP), a major contributor to the regulation of neuronal excitability, is reduced in animals that have acquired several types of hippocampus-dependent memory tasks and also following synaptic potentiation by high frequency stimulation. BK channels underlie the fast AHP and contribute to spike repolarization, and this AHP is reduced in animals that successfully acquired trace-eyeblink conditioning. This suggests that BK channel function is activity-dependent, but the mechanisms are unknown. In this study, we found that blockade of BK channels with paxilline (10 μM) decreased IAHP amplitude and increased spike half-width and instantaneous frequency in response to a +100 pA depolarization. In addition, induction of long term potentiation (LTP) by theta burst stimulation (TBS) in CA1 pyramidal neurons reduced BK channel’s contribution to IAHP, spike repolarization, and instantaneous frequency. This result indicates that BK channel activity is decreased following synaptic potentiation. Interestingly, blockade of mammalian target of rapamycin (MTORC1) with rapamycin (400 nM) following synaptic potentiation restored BK channel function, suggesting a role for protein translation in signaling events which decreased postsynaptic BK channel activity following synaptic potentiation.