Title NSF Engineering Research Center for Revolutionizing Metallic Biomaterials
Description: The Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB) will pursue revolutionary advances in metallic biomaterials and the underlying sciences and technologies, leading to engineered systems that will interface with the human body to prolong and improve quality of life. This research effort is coupled with the development of a vibrant, diverse workforce well-prepared for the global challenges and opportunities of the 21st century. The ERC proposes to develop the fundamental knowledge and technology needed to advance biocompatible and biodegradable metal-based, implantable systems with feedback control for reconstruction and regeneration. The research and technology development will be aided by industrial input and clinical assessments. The ERC’s education program is designed to develop innovative and adaptive engineers. Seamlessly integrated undergraduate and graduate bioengi- neering programs will be established at North Carolina A&T State University (NCAT) to support this goal.
Title Mechanisms of Polyploidy and Aneuploidy in the Liver
Description: Nearly 25 million Americans are affected by liver dysfunction, and liver diseases are the 10th leading cause of death in the US. There is a clear and urgent need for developing new alternatives to whole organ replacement. A better understanding of liver biology is required to improve existing approaches and to innovate therapies for the treatment of liver diseases, including viral hepatitis and steatohepatitis. Hepatocytes, the primary functional cell type in the liver, display a range of chromosomal diversity resulting from prevalent physiological polyploidy (>90% in mice and 50% in humans) and aneuploidy (60% in mice and 30-90% in humans). In eukaryotic organisms, cells usually contain a diploid genome comprised of pairs of homologous chromosomes. Polyploidy refers to gains in entire sets of chromosomes, and aneuploidy refers to gains and losses of individual chromosomes. The roles of hepatic polyploidy and aneuploidy represent a major gap in our current understanding of liver biology. We recently found that aneuploidy enhances the regenerative capacity of the mouse liver. In response to Tyrosinemia-induced injury, that is normally toxic to the liver, we identified a subset of aneuploid hepatocytes that was resistant to the disease. The data suggest that aneuploid hepatocytes are endowed with enhanced capacity for adaptation and regeneration. Our central hypothesis is that aneuploidy functions as an adaptive mechanism in response to hepatic injury. The goals of this application are to identify mechanisms regulating hepatic aneuploidy/polyploidy and to unravel how aneuploidy affects liver function. To investigate these questions, we propose in Specific Aim 1 to determine whether polyploid hepatocytes are necessary for development of aneuploid livers. Experiments will characterize hepatic cell divisions, karyotypes and stress response in E2f7/E2f8 knockout mice, which have normal liver function but are depleted of polyploid hepatocytes. In Specific Aim 2, we will dissect the role of a novel regulator of hepatic polyploidy, recently identified in our laboratory, microRNA-122 (miR-122). Experiments will determine how miR-122 alters ploidy and aneuploidy throughout life. We will also identify cellular and molecular mechanisms by which miR-122 regulates hepatic ploidy. Finally, in Specific Aim 3, we will determine how random karyotypes (in aneuploid hepatocytes) affect function in the liver. We will utilize a novel xenotransplantation model to examine clonal nodules of regenerating human hepatocytes. Experiments will measure aneuploidy and determine gene expression profiles in these nodules. Together, these studies will define the extent to which aneuploidy affects liver repair/regeneration as well as the molecular mechanisms that control this process. Understanding how aneuploid hepatocytes arise and function will provide new and crucial insights into liver homeostasis, diseases and treatments.
Title Mini-Livers Derived from Human IPS Cells for Modeling Steatosis and Therapy
Description: Our long-term goal is to develop a natural hepatic scaffold with multi-cellular cues for complete and stable maturation of stem-derived liver cells to engineer functional livers in vitro and use them for modeling liver steatosis and therapeutics. The objectives of the proposed study are to develop an organ culture system for liver engineering with induced pluripotent stem (iPS) cell-derived liver cells, and investigate its employment to understand pathogenesis, natural history and development of early detection tools and treatments for fatty liver diseases. The central hypothesis to be tested here is that the decellularized natural liver scaffold can be extensively repopulated, will provide a stable organ-like environment for the metabolic maturation of iPS derived liver cells, and may be used as an approach to induce formation of functional mini-livers using human wild type iPS cells or iPS cells after genetic engineer for fatty liver disease by knockdown of SIRT1 and/or (key gene implicated with liver steatosis formation). The rationale for the proposed research is that, once human liver tissue with multi-cellular cues can be reproducibly manufactured in vitro with normal and disease phenotypes, development of liver steatosis can be manipulated pharmacologically, resulting in new and innovative approaches to the prevention and treatment of a variety of liver diseases. The work described here is expected to i) generate a metabolic maturation system for human iPS cell-derived liver cells to form tissue, ii) establish human iPS cells carrying shRNA mediated conditional knockdown of SIRT1 and iii) develop a novel approach for modeling an organ-like environment to determine the role of SIRT1 in human liver steatosis or fatty liver disease. The results of this work will also have a positive impact by establishing the basis and platform for future sophisticated organ engineering techniques that incorporates several different cell types and may lead to development of entire organs in vitro, these techniques could be applied to study other liver diseases (e.g. metabolic diseases) and is expected to be a major contribution to the fields of stem cells engineering and liver steatosis.
Title Applying extracellular matrix technology to neuroprotect and to repair injured retina and optic nerve
Description: ECM technology as an early preventative for reducing secondary ocular trauma. After ocular trauma, secondary injury due to inflammation and a default healing response that forms scar tissue, in injured central nervous system (CNS) tissues, are major factors contributing to permanent vision loss. To address this problem, we are developing an injectable, ECM hydrogel and an ECM biohybrid wrap. Both platforms are designed to stabilize trauma to the retina or to the optic nerve and limit inflammation, edema, and scarring. ECM technology uses natural ECM bioscaffolds, derived by decellularizing specific tissues or organs, to promote a positive healing response in tissues the body is unable to repair functionally by default. In both preclinical and clinical models, ECM bioscaffolds can facilitate site-specific, functional repair in various peripheral tissues, including heart, lung, esophagus, muscle, tendon, skin, and peripheral nerves among others. Though the exact mechanisms are unknown, ECM bioscaffolds act, in part, by attracting endogenous stem cells and promoting site-appropriate differentiation, vascularization, neurogenesis, and a pro-repair M2 phenotype in macrophage and microglia. We hypothesize ECM technology will preserve or restore visual function by altering the default healing response to retinal or optic nerve injury in four key areas: 1) Increase RGC survival and axon regeneration. 2) Increase endogenous stem cell recruitment to the wound. 3) Increase M2 polarization in macrophages and microglia at the wound site. 4) Decrease glial scarring.
Title Non-invasive imaging of the in situ restoration of brain tissue
Description: Regenerative medicine is increasingly finding translations from the bench to the bedside. As stem cells are integrated with biomaterials for in situ tissue engineering, the complexity of the procedure is increasing and it is becoming important to monitor how these processes interact over time in vivo. Translation of this non-invasive monitoring into patients requires the development and implementation of appropriate approaches. Our proposal here aims to develop chemical exchange saturation transfer (CEST), a non-invasive MRI technique, as a core platform to visualize multiple cell types, as well as biomaterials, while maintaining our ability to characterize newly forming tissue with other MRI techniques, such as MRS, as well as diffusion and perfusion MRI. Very significant technological, as well as neurobiological challenges, however, need to be addressed before we can integrate this multi-parametric MRI into an efficient non-invasive assessment of in situ tissue engineering. The proposed studies aim to address these challenges and provide a framework within which we can eventually explore the therapeutic potential of this approach. If a newly functional tissue can be generated to replace that which is lost due to the stroke, this approach could indeed dramatically change the long-term outcome after stroke.
Title 3D Video Augmented High-Resolution Ultrasound Imaging for Monitoring Nerve Regeneration and Chronic Rejection after Composite Tissue Allotransplantation
Description: This technology has direct relevance to the FY13 PRMRP topic area of Composite Tissue Transplantation. During the past decade, more than 100 hand and facial transplants have been performed around the world, including over 90 with encouraging outcomes. The University of Pittsburgh is one of the key centers for these exciting new surgical procedures. Key to their success is the timely regrowth of nerves into the new transplanted tissue before muscle has time to degenerate, and the survival of vital arteries that tend to thicken with chronic rejection of the transplant, putting transplanted tissue at risk. Monitoring nerves and arteries is thus essential for appropriate measures to be taken in time and, in the research setting, it is required so that new therapies can be developed. To be safe, monitoring of nerves and arteries in these patients must not involve taking biopsies. Imaging techniques using ultrasound are promising because of their safety and low cost, and recent advances in ultrasound resolution have made subtle changes in nerves and arteries more easily visualized. However, ultrasound still suffers from an inability to accurately record where in a patient a given ultrasound scan has been acquired. The knowledge of scan location is particularly important for comparing ultrasound scans from one month to the next, and from one patient to another.
Co Investigator Derek Angus, Robert Parker, Francis Pike, David Swigon
Title Model-Based Decisions in Sepsis (MODS)
Description: Large randomized clinical trials of immunomodulatory interventions for acute inflammatory diseases such as sepsis have had a dismal track record. The biological complexity of the host-pathogen interaction and the potential large impact of a successful treatment on the health care system and society position diseases such as sepsis as ideal test beds for model-based therapeutic approaches, as proposed in the FDA critical path document and the NIH roadmap initiative. Yet, there is a paucity of organism-level computational models of inflammation. More fundamental however, is the lack of human data sets where such models could be validated. Such a data set would be extraordinarily expensive to assemble and is highly unlikely to be acquired merely for testing model-based interventions in the absence of models with demonstrated validity. The NIH-funded Protocolized Care for Early Septic Shock (ProCESS) study is currently examining the impact of early resuscitation in victims of severe sepsis in a 1350 patient prospective randomized trial and will produce a data set with a granularity that will not only help to understand the processes involved in sepsis, but also the biological consequences of a physiologic goal-directed treatment protocol. The overarching goal of the program outlined in this proposal is to validate computational models of human sepsis using data from the ProCESS study through advanced mathematical and computational methods. We have assembled a transdisciplinary group of modelers and clinicians with an eloquent track record of successful collaboration on developing, calibrating and testing in silico models of acute inflammation, and of sepsis in particular, of different levels of granularity. We believe that validation of in silico models in a large clinically relevant cohort is absolutely crucial to the legitimization of computational modeling as a technology that will prove pivotal to the design of smarter randomized interventional trials in general, and of personalized therapies in particular. Leveraging data and preliminary analyses from the ProCESS trial on the one hand and an extensive existing transdisciplinary effort at expanding existing computational models of the acute inflammatory response on the other will also provide an unprecedented opportunity to gain mechanistic understanding of the processes leading to organ failure and death, systemic recovery and unexpected failure.
PI Trevor Arnoult Snyder (VADovations, Inc., Oklahoma City, OK)
PI of Sub-Contract Peter Wearden
Co-Investigators William Wagner, Marina Kameneva, Timothy Maul
Title Small blood pumps for small patients
Description: Heart failure and congenital heart defects threaten the lives of several thousand children each year. The only FDA-approved long term pediatric heart support device is the Berlin Heart Excor, which is based on 30+ year old technology and is fraught with complications including blood clots forming in the device requiring frequent device replacement. The recipients of this technology are at high risk for strokes, bleeding, and infection and the pumps are driven by a large 220 lb console, which limits patient mobility and prevents hospital discharge. In spite of these severe limitations, 90% of Excor recipients survive to transplant, although the median duration of support is only 35 days. A safer device would dramatically reduce the complications of support, permit discharge to home, and allow doctors to deploy the technology earlier, before a child reaches the brink of death. VADovations is developing a miniature implantable pump platform, the Revolution, in which minor modifications of 2 components can be implemented to adjust the pump performance to support the right or left side of the heart. The devices are 8 mm in diameter and 50 mm in length, about the size of a ‘AAA’battery, compared to the market leading Heartmate II, which is 47 mm in maximum diameter and 95 mm in length, the size of a ‘D’cell battery. Our adult Revolution RVAD can safely generate the lower blood rates needed for a pediatric left heart assist device and has demonstrated exceptionally low blood trauma in bench-top studies and during implants in sheep for durations up to one month with no long-term blood thinners. Building upon these promising results, we propose a Fast Track, combined Phase I/II SBIR to re-purpose the Revolution RVAD as a pediatric left heart assist device, the Revolution MINI, for children ages 1 and up. Then we will revise the design to create the Revolution NEO for neonates and infants, aged 0-1, who represent the largest clinical need for pediatric heart support. During Phase I, we will demonstrate the feasibility and efficacy of the MINI for pediatric blood flow rates and pressures during in vitro and short term animal experiments. In Phase II, we will conduct chronic animal implants to evaluate the long-term function, biocompatibility, and durability of the pumps and perform verification and validation studies of the Revolution MINI system to prepare for a US clinical trial. Throughout the program, we will focus considerable efforts on anatomic fit modeling and studies to devise approaches so that these devices can be implanted in the smaller bodies of children, to avoid pumps protruding from the body, as occurs with the paracorporeal Excor. Superior hemocompatibility, smaller size, and the ability to leverage adult system components, combine to produce pediatric heart assist devices that will offer fewer complications, permit patient discharge to home, and be economically viable to revolutionize the treatment of pediatric heart failure.
Description: The U.S. Army Medical Research and Materiel Command has announced the grants awarded under the Armed Forces Institute of Regenerative Medicine: Warrior Restoration Consortium, known as AFIRM-II.
The AFIRM II program is intended to continue the success of the original AFIRM program, which was first funded in 2008. AFIRM-I focused on limb repair, craniofacial repair, burn repair, scarless wound repair, and compartment syndrome. The AFIRM program emphasized getting projects through advanced development, so that the innovations could be used for patients who need them. During the first program, more than 180 patients received treatment with AFIRM-funded technologies.