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1. Multi-Organ Exchange

   https://doi.org/10.1613/jair.4919  

   Dickerson, John P.; Sandholm, Tuomas (September 2017, Journal of Artificial Intelligence Research)

   Kidney exchange, where candidates with organ failure trade incompatible but willing donors, is a life-saving alternative to the deceased donor waitlist, which has inadequate supply to meet demand. While fielded kidney exchanges see huge benefit from altruistic kidney donors (who give an organ without a paired needy candidate), a significantly higher medical risk to the donor deters similar altruism with livers. In this paper, we begin by exploring the idea of large-scale liver exchange, and show on demographically accurate data that vetted kidney exchange algorithms can be adapted to clear such an exchange at the nationwide level. We then propose cross-organ donation where kidneys and livers can be bartered for each other. We show theoretically that this multi-organ exchange provides linearly more transplants than running separate kidney and liver exchanges. This linear gain is a product of altruistic kidney donors creating chains that thread through the liver pool; it exists even when only a small but constant portion of the donors on the kidney side of the pool are willing to donate a liver lobe. We support this result experimentally on demographically accurate multi-organ exchanges. We conclude with thoughts regarding the fielding of a nationwide liver or joint liver-kidney exchange from a legal and computational point of view. 

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2. Organ Evolution: Emergence of Multicellular Function

   https://doi.org/10.1146/annurev-cellbio-111822-121620  

   Parker, Joseph (October 2024, Annual Review of Cell and Developmental Biology)

   Instances of multicellularity across the tree of life have fostered the evolution of complex organs composed of distinct cell types that cooperate, producing emergent biological functions. How organs originate is a fundamental evolutionary problem that has eluded deep mechanistic and conceptual understanding. Here I propose a cell- to organ-level transitions framework, whereby cooperative division of labor originates and becomes entrenched between cell types through a process of functional niche creation, cell-type subfunctionalization, and irreversible ratcheting of cell interdependencies. Comprehending this transition hinges on explaining how these processes unfold molecularly in evolving populations. Recent single-cell transcriptomic studies and analyses of terminal fate specification indicate that cellular functions are conferred by modular gene expression programs. These discrete components of functional variation may be deployed or combined within cells to introduce new properties into multicellular niches, or partitioned across cells to establish division of labor. Tracing gene expression program evolution at the level of single cells in populations may reveal transitions toward organ complexity. 

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3. Isochoric Supercooling Organ Preservation System

   https://doi.org/10.3390/bioengineering10080934  

   Năstase, Gabriel; Botea, Florin; Beșchea, George-Andrei; Câmpean, Ștefan-Ioan; Barcu, Alexandru; Neacșu, Ion; Herlea, Vlad; Popescu, Irinel; Chang, Tammy T; Rubinsky, Boris; et al (August 2023, Bioengineering)

   This technical paper introduces a novel organ preservation system based on isochoric (constant volume) supercooling. The system is designed to enhance the stability of the metastable supercooling state, offering potential long-term preservation of large biological organs at subfreezing temperatures without the need for cryoprotectant additives. Detailed technical designs and usage protocols are provided for researchers interested in exploring this field. The paper also presents a control system based on the thermodynamics of isochoric freezing, utilizing pressure monitoring for process control. Sham experiments were performed using whole pig liver sourced from a local food supplier to evaluate the system’s ability to sustain supercooling without ice nucleation for extended periods. The results demonstrated sustained supercooling without ice nucleation in pig liver tissue for 24 and 48 h. These findings suggest the potential of this technology for large-volume, cryoprotectant-free organ preservation with real-time control over the preservation process. The simplicity of the isochoric supercooling device and the design details provided in the paper are expected to serve as encouragement for other researchers in the field to pursue further research on isochoric supercooling. However, final evidence that these preserved organs can be successfully transplanted is still lacking. 

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4. 3D Bioprinting for Organ Regeneration

   https://doi.org/10.1002/adhm.201601118  

   Cui, Haitao; Nowicki, Margaret; Fisher, John_P; Zhang, Lijie_Grace (December 2016, Advanced Healthcare Materials)

   Regenerative medicine holds the promise of engineering functional tissues or organs to heal or replace abnormal and necrotic tissues/organs, offering hope for filling the gap between organ shortage and transplantation needs. Three‐dimensional (3D) bioprinting is evolving into an unparalleled biomanufacturing technology due to its high‐integration potential for patient‐specific designs, precise and rapid manufacturing capabilities with high resolution, and unprecedented versatility. It enables precise control over multiple compositions, spatial distributions, and architectural accuracy/complexity, therefore achieving effective recapitulation of microstructure, architecture, mechanical properties, and biological functions of target tissues and organs. Here we provide an overview of recent advances in 3D bioprinting technology, as well as design concepts of bioinks suitable for the bioprinting process. We focus on the applications of this technology for engineering living organs, focusing more specifically on vasculature, neural networks, the heart and liver. We conclude with current challenges and the technical perspective for further development of 3D organ bioprinting. 

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5. Organ structure and bacterial microbiogeography in a reproductive organ of the Hawaiian bobtail squid reveal dimensions of a defensive symbiosis

   https://doi.org/10.1128/aem.02163-24  

   Kamp, Derrick L; Kerwin, Allison H; McAnulty, Sarah J; Nyholm, Spencer V (May 2025, Applied and Environmental Microbiology)

   Rudi, Knut (Ed.)

   ABSTRACT Many plants and animals house symbiotic microorganisms in specialized tissues or organs. Here, we used multidimensionalin situimaging techniques to illuminate how host organ structure and bacterial microbiogeography contribute to the symbiotic function of an organ in the Hawaiian bobtail squid,Euprymna scolopes. Along with the well-studied light organ, femaleE. scolopesharbor a community of bacteria in the accessory nidamental gland (ANG). The ANG is a dense network of epithelium-lined tubules, some of which are dominated by a single bacterial taxon. These bacteria are deposited into squid eggs, where they defend the developing embryos from harmful biofouling. This study used a combination of imaging techniques to visualize different dimensions of the ANG and its bacterial communities. Imaging entire organs with light sheet microscopy revealed that the ANG is a composite tissue of individual, non-intersecting tubules that each harbor their own bacterial population. The organ is bisected, with tubules converging toward two points at the posterior end. At these points, tubules empty into a space where bacteria can mix with squid jelly to be deposited onto eggs. Observations of the symbiotic community correlated bacterial taxa with cell morphology and revealed that tubule populations varied: some tubules contained populations of mixed taxa, whereas others contained only one bacterial genus. Together, these data shed light on how bacterial populations interact within the ANG and how the host uses physical structure to maintain and employ a symbiotic bacterial population in a defensive context.IMPORTANCESequence-based microbiome studies have revealed much about how hosts interact with communities of symbiotic microbiota but often lack a spatial understanding of how microbes relate to each other and the host in which they reside. This study uses a combination of microscopy techniques to reveal how the structure of a symbiotic organ in the female bobtail squid,Euprymna scolopes, houses diverse, beneficial bacterial populations and deploys them for egg defense. These findings suggest that spatial partitioning may be key to harboring a diverse population of antimicrobial-producing bacteria and establishing a foundation for further understanding how host structures mediate symbiotic interactions. 

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