Enhancing patient outcomes: the role of clinical utility in guiding healthcare providers in curating radiology AI applications.

With advancements in artificial intelligence (AI) dominating the headlines, diagnostic imaging radiology is no exception to the accelerating role that AI is playing in today's technology landscape. The number of AI-driven radiology diagnostic imaging applications (digital diagnostics) that are both commercially available and in-development is rapidly expanding as are the potential benefits these tools can deliver for patients and providers alike. Healthcare providers seeking to harness the potential benefits of digital diagnostics may consider evaluating these tools and their corresponding use cases in a systematic and structured manner to ensure optimal capital deployment, resource utilization, and, ultimately, patient outcomes-or clinical utility. We propose several guiding themes when using clinical utility to curate digital diagnostics.

Mesenchymal stromal cell-derived exosome-rich fractionated secretome confers a hepatoprotective effect in liver injury.

BACKGROUND: Mesenchymal stromal cells (MSCs) are an attractive therapeutic agent in regenerative medicine. Recently, there has been a paradigm shift from differentiation of MSCs to their paracrine effects at the injury site. Several reports elucidate the role of trophic factors secreted by MSCs toward the repair of injured tissues. We hypothesize that fractionating the MSC secretome will enrich exosomes containing soluble bioactive molecules, improving its therapeutic potential for liver failure. METHODS: Rat bone marrow MSCs were isolated and the conditioned media filtered, concentrated and ultracentrifuged to generate fractionated secretome. This secretome was characterized for the presence of exosomes and recovery from liver injury assessed in in-vitro liver injury models. The results were further validated in vivo. RESULTS: Studies on in-vitro liver injury models using acetaminophen and hydrogen peroxide show better cell recovery and reduced cytotoxicity in the presence of fractionated as opposed to unfractionated secretome. Further, the cells showed reduced oxidative stress in the presence of fractionated secretome, suggesting a potential antioxidative effect. These results were further validated in vivo in liver failure models, wherein improved liver regeneration in the presence of fractionated secretome (0.819 ± 0.035) was observed as compared to unfractionated secretome (0.718 ± 0.042). CONCLUSIONS: The work presented is a proof of concept that fractionating the secretome enriches certain bioactive molecules involved in the repair and recovery of injured liver tissue. Exosome enriched mesenchymal stromal cell-derived fractionated secretome potentiates recovery upon injection in injured liver.

Decellularized Liver Matrix-Modified Cryogel Scaffolds as Potential Hepatocyte Carriers in Bioartificial Liver Support Systems and Implantable Liver Constructs.

Recent progress in the use of decellularized organ scaffolds as regenerative matrices for tissue engineering holds great promise in addressing the issue of donor organ shortage. Decellularization preserves the mechanical integrity, composition, and microvasculature critical for zonation of hepatocytes in the liver. Earlier studies have reported the possibility of repopulating decellularized matrices with hepatic cell lines or stem cells to improve liver regeneration. In this work, we study the versatility of the decellularized liver matrix as a substrate coating of three-dimensional cryogel scaffolds. The coated cryogels were analyzed for their ability to maintain hepatic cell growth and functionality in vitro, which was found to be significantly better than the uncoated cryogel scaffolds. The decellularized liver matrix-coated cryogel scaffolds were evaluated for their potential application as a cell-loaded bioreactor for bioartificial liver support and as an implantable liver construct. Extracorporeal connection of the coated cryogel bioreactor to a liver failure model showed improvement in liver function parameters. Additionally, offline clinical evaluation of the bioreactor using patient-derived liver failure plasma showed its efficacy in improving liver failure conditions by approximately 30-60%. Furthermore, implantation of the decellularized matrix-coated cryogel showed complete integration with the native tissue as confirmed by hematoxylin and eosin staining of tissue sections. HepG2 cells and primary human hepatocytes seeded in the coated cryogel scaffolds implanted in the liver failure model maintained functionality in terms of albumin synthesis and cytochrome P450 activity post 2 weeks of implantation. In addition, a 20-60% improvement in liver function parameters was observed post implantation. These results, put together, suggest a possibility of using the decellularized matrix-coated cryogel scaffolds for liver tissue engineering applications.

Optimized performance of the integrated hepatic cell-loaded cryogel-based bioreactor with intermittent perfusion of acute liver failure plasma.

Acute liver failure (ALF) plasma has cytotoxic effects on the cell-loaded bioreactor in bioartificial liver support systems due to the presence of innumerable hepatotoxic compounds that adversely affect the morphology and functionality of the cells. We have designed a hybrid bioreactor that integrates a hepatic cell-loaded cryogel disc and an activated carbon cloth in one compact unit, with potential application as a bioartificial liver support. In this article, we assess the performance of this integrated hybrid cryogel-based bioreactor in a perfusion-based culture system and analyze its functionality and longevity in the presence of intermittent exposure to ALF plasma. The bioreactor maintained functionality in terms of glucose consumption and albumin synthesis for up to 40 days under perfusion. Additionally, intermittent perfusion of plasma from rodent models of ALF resulted in a decrease in viability and functionality only after the second spike of plasma, with the bioreactor maintaining its functionality even after the first spike. Similar results were obtained with patient plasma indicating the potential to reuse the bioreactor for multiple sessions of liver dialysis. Collectively, these results suggest the potential of the integrated cryogel-based bioreactor to be used at most twice before being disposed of. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 259-269, 2018.

Alleviating liver failure conditions using an integrated hybrid cryogel based cellular bioreactor as a bioartificial liver support.

Conventionally, some bioartificial liver devices are used with separate plasmapheresis unit to separate out plasma from whole blood and adsorbent column to detoxify plasma before it passes through a hepatocytes-laden bioreactor. We aim to develop a hybrid bioreactor that integrates the separate modules in one compact design improving the efficacy of the cryogel based bioreactor as a bioartificial liver support. A plasma separation membrane and an activated carbon cloth are placed over a HepG2-loaded cryogel scaffold in a three-chambered bioreactor design. This bioreactor is consequently connected extracorporeally to a rat model of acute liver failure for 3 h and major biochemical parameters studied. Bilirubin and aspartate transaminase showed a percentage decrease of 20-60% in the integrated bioreactor as opposed to 5-15% in the conventional setup. Urea and ammonia levels which showed negligible change in the conventional setup increase (40%) and decrease (18%), respectively in the integrated system. Also, an overall increase of 5% in human albumin in rat plasma indicated bioreactor functionality in terms of synthetic functions. These results were corroborated by offline evaluation of patient plasma. Hence, integrating the plasmapheresis and adsorbent units with the bioreactor module in one compact design improves the efficacy of the bioartificial liver device.

Bilayer Cryogel Wound Dressing and Skin Regeneration Grafts for the Treatment of Acute Skin Wounds.

In this study, the potential of cryogel bilayer wound dressing and skin regenerating graft for the treatment of surgically created full thickness wounds was evaluated. The top layer was composed of polyvinylpyrrolidone-iodine (PVP-I) cryogel and served as the antiseptic layer, while the bottom regenerative layer was made using gelatin cryogel. Both components of the bilayer showed typical features of a cryogel interconnected macropore network, rapid swelling, high water uptake capacity of about 90%. Both PVP and gelatin cryogel showed high tensile strength of 45 and 10 kPa, respectively. Gelatin cryogel sheets were essentially elastic and could be stretched without any visible deformation. The antiseptic PVP-I layer cryogel sheet showed sustained iodine release and suppressed microbial growth when tested with skin pathogens (zone of inhibition ∼2 cm for sheet of 0.9 cm diameter). The gelatin cryogel sheet degraded in vitro in weeks. The gelatin cryogel sheet supported cell infiltration, attachment, and proliferation of fibroblasts and keratinocytes. Microparticles loaded with bioactive molecules (mannose-6-phosphate and human fibrinogen) were also incorporated in the gelatin cryogel sheets for their role in enhancing skin regeneration and scar free wound healing. In vivo evaluation of healing capacity of the bilayer cryogel was checked in rabbits by creating full thickness wound defect (diameter 2 cm). Macroscopic and microscopic observation at regular time intervals for 4 weeks demonstrated better and faster skin regeneration in the wound treated with cryogel bilayer as compared to untreated defect and the repair was comparable to commercial skin regeneration scaffold Neuskin-F. Complete skin regeneration was observed after 4 weeks of implantation with no sign of inflammatory response. Defects implanted with cryogel having mannose-6-phosphate showed no scar formation, while the wound treated with bilayer incorporated with human fibrinogen microparticles showed early signs of skin regeneration; epidermis formation occurred at 2 weeks after implantation.

Fabrication of macroporous cryogels as potential hepatocyte carriers for bioartificial liver support.

Two different cryogels composed of copolymer of acrylonitrile (AN) and N-vinyl-2-pyrrolidone (NVP) (poly(AN-co-NVP)) and interpenetrated polymer networks (IPN) of chitosan and poly(N-isopropylacrylamide) (poly(NiPAAm)-chitosan) were fabricated by gelation at sub-zero temperatures. The two cryogels possess an interconnected network of macropores of size 20-100 µm and efficient transport properties as determined by physiochemical analysis. Both cryogels support in vitro growth and function of fibroblasts (COS-7) and human liver hepatocarcinoma cells (HepG2). The cryogels are hemocompatible as demonstrated by low albumin adsorption and platelet adherence. Furthermore, in vivo implantation of poly(NiPAAm)-chitosan cryogel in mice shows its biocompatibility with the surrounding tissue. Primary rat hepatocytes grown on poly(NiPAAm)-chitosan cryogel for 96 h formed cellular aggregates and maintained their functions in terms of, ammonia removal, ureagenesis and drug detoxification. Cryogel-based closed continuous bioreactor systems could maintain HepG2 cells at high density for 7 days. Off-line clinical evaluation of these cryogel-based bioreactors showed the ability of immobilized cells to detoxify circulating plasma obtained from patients with acute on chronic liver failure (ACLF). Altogether, the presented data suggests cryogels as a potential bioreactor matrix for bio-artificial liver support system.

Advancements in in vitro hepatic models: application for drug screening and therapeutics.

The liver is one of the most complex organs in the body, performing a multitude of functions. Liver tissue engineering is a combination of various strategies that aim at generating functional liver tissue that can help restore and/or support the ailing liver as it recuperates. Conventionally, in vitro culture has involved growing cells in different media compositions or layering them on matrices largely composed of native ECM components such as collagen or Matrigel. With recent advances in technology, more sophisticated techniques are being devised that are better equipped to capture distinct features of the liver in an in vivo microenvironment. Three-dimensional (3D) cultures of liver cells in 3D scaffolds, as spheroids or cell sheets, allow for a high degree of cell-cell and cell-matrix interaction and an in vivo-like architecture. More recently, decellularized matrices have been used as scaffolds that support ideal cell-matrix interactions. Microfabrication technologies initially used to pattern semiconductors in the integrated circuit industry have grown out of this field and now encompass a variety of methods to etch patterns onto both 2D and 3D scaffolds to allow incorporation of custom-made features resembling the fluid network and organization in native liver. This improvisation permits for enhanced vascularization and oxygen diffusion to the in vitro liver tissue. In this review, we discuss the various configurations that have been implemented in the in vitro culture of liver cells and their application in liver therapeutics in the form of implantable liver tissue constructs and tools for drug screening.

Biomaterials for liver tissue engineering.

Liver extracellular matrix (ECM) composition, topography and biomechanical properties influence cell-matrix interactions. The ECM presents guiding cues for hepatocyte phenotype maintenance, differentiation and proliferation both in vitro and in vivo. Current understanding of such cell-guiding cues along with advancement of techniques for scaffold fabrication has led to evolution of matrices for liver tissue culture from simple porous scaffolds to more complex 3D matrices with microarchitecture similar to in vivo. Natural and synthetic polymeric biomaterials fabricated in different topographies and porous matrices have been used for hepatocyte culture. Heterotypic and homotypic cell interactions are necessary for developing an adult liver as well as an artificial liver. A high oxygen demand of hepatocytes as well as graded oxygen distribution in liver is another challenging attribute of the normal liver architecture that further adds to the complexity of engineered substrate design. A balanced interplay of cell-matrix interactions along with cell-cell interactions and adequate supply of oxygen and nutrient determines the success of an engineered substrate for liver cells. Techniques devised to incorporate these features of hepatic function and mimic liver architecture range from maintaining liver cells in mm-sized tailor-made scaffolds to a more bottoms up approach that starts from building the microscopic subunit of the whole tissue. In this review, we discuss briefly various biomaterials used for liver tissue engineering with respect to design parameters such as scaffold composition and chemistry, biomechanical properties, topography, cell-cell interactions and oxygenation.