Authors: Manni ML, Czajka CA, Oury TD, Gilbert TW.
Title: Extracellular Matrix Powder Protects Against Bleomycin-Induced Pulmonary Fibrosis.
Summary: Pulmonary fibrosis refers to a group of lung diseases characterized by inflammation, fibroblast proliferation, and excessive collagen deposition. Although the mechanisms underlying pulmonary fibrosis are poorly understood, current evidence suggests that epithelial injury contributes to the development of fibrosis. Regenerative medicine approaches using extracellular matrix (ECM) scaffolds have been shown to promote site-specific tissue remodeling. This led to the hypothesis that particulate ECM would promote normal tissue repair and attenuate bleomycin-induced pulmonary fibrosis. C57BL/6 mice were treated intratracheally with bleomycin or saline with or without a particulate form of ECM scaffold from porcine urinary bladder matrix (UBM-ECM) or enzymatically digested UBM-ECM. Mice were sacrificed 5 and 14 days after exposure. Compared to control mice, bleomycin-exposed mice had similar increases in inflammation in the bronchoalveolar lavage fluid regardless of UBM-ECM treatment. However, 14 days after exposure, lung histology and collagen levels revealed that mice treated with bleomycin and the particulate or digested UBM-ECM had negligible fibrosis, whereas mice given only bleomycin had marked fibrosis. Administration of the particulate UBM-ECM 24 h after bleomycin exposure also significantly protected against pulmonary injury. In vitro epithelial cell migration and wound healing assays revealed that particulate UBM-ECM promoted epithelial cell chemotaxis and migration. This suggests that promotion of epithelial wound repair may be one mechanism in which UBM-ECM limits pulmonary fibrosis.
Title: Injectable fibroblast growth factor-2 coacervate for persistent angiogenesis.
Summary: Enhancing the maturity of the newly formed blood vessels is critical for the success of therapeutic angiogenesis. The maturation of vasculature relies on active participation of mural cells to stabilize endothelium and a basal level of relevant growth factors. We set out to design and successfully achieved robust angiogenesis using an injectable polyvalent coacervate of a polycation, heparin, and fibroblast growth factor-2 (FGF2). FGF2 was loaded into the coacervate at nearly 100% efficiency. In vitro assays demonstrated that the matrix protected FGF2 from proteolytic degradations. FGF2 released from the coacervate was more effective in the differentiation of endothelial cells and chemotaxis of pericytes than free FGF2. One injection of 500 ng of FGF2 in the coacervate elicited comprehensive angiogenesis in vivo. The number of endothelial and mural cells increased significantly, and the local tissue contained more and larger blood vessels with increased circulation. Mural cells actively participated during the whole angiogenic process: Within 7 d of the injection, pericytes were recruited to close proximity of the endothelial cells. Mature vasculature stabilized by vascular smooth muscle cells persisted till at least 4 wk. On the other hand, bolus injection of an identical amount of free FGF2 induced weak angiogenic responses. These results demonstrate the potential of polyvalent coacervate as a new controlled delivery platform.
Title: Esophageal preservation in five male patients after endoscopic inner-layer circumferential resection in the setting of superficial cancer: a regenerative medicine approach with a biologic scaffold.
Title: Rescue of lethal hepatic failure by hepatized lymph nodes in mice.
Summary: BACKGROUND & AIMS: Hepatocyte transplantation is a potential therapeutic approach for liver disease. However, most patients with chronic hepatic damage have cirrhosis and fibrosis, which limit the potential for cell-based therapy of the liver. The development of an ectopic liver as an additional site of hepatic function represents a new approach for patients with end-stage liver disease. We investigated the development and function of liver tissue in lymph nodes in mice with liver failure.
Title: Substantial expression of mature elastin in arterial constructs.
Summary: Mature elastin synthesis is a key challenge in arterial tissue engineering. Most engineered vessels lack elastic fibers in the medial layer and those present are poorly organized. The objective of this study is to increase mature elastin synthesis in small-diameter arterial constructs. Adult primary baboon smooth muscle cells (SMCs) were seeded in the lumen of porous tubular scaffolds fabricated from a biodegradable elastomer, poly(glycerol sebacate) (PGS) and cultured in a pulsatile flow bioreactor for 3 wk. We tested the effect of pore sizes on construct properties by histological, biochemical, and mechanical evaluations. Histological analysis revealed circumferentially organized extracellular matrix proteins including elastin and the presence of multilayered SMCs expressing calponin and α-smooth muscle actin. Biochemical analysis demonstrated that the constructs contained mature elastin equivalent to 19% of the native arteries. Mechanical tests indicated that the constructs could withstand up to 200 mmHg burst pressure and exhibited compliance comparable to native arteries. These results show that nontransfected cells in PGS scaffolds in unsupplemented medium produced a substantial amount of mature elastin within 3 wk and the elastic fibers had similar orientation as those in native arteries. The 25-32 μm pore size supported cell organization and elastin synthesis more than larger pore sizes. To our knowledge, there was no prior report of the synthesis of mature and organized elastin in arterial constructs without exogenous factors or viral transduction.
Authors: Du Y, Roh DS, Funderburgh ML, Mann MM, Marra KG, Rubin JP, Li X, Funderburgh JL.
Title: Adipose-derived stem cells differentiate to keratocytes in vitro.
Summary: Adipose-derived stem cells (ADSC) are an abundant population of adult stem cells with the potential to differentiate into several specialized tissue types, including neural and neural crest-derived cells. This study sought to determine if ADSC express keratocyte-specific phenotypic markers when cultured under conditions inducing differentiation of corneal stromal stem cells to keratocytes.
Authors: Lopez F, Di Bartolo C, Piazza T, Passannanti A, Gerlach JC, Gridelli B, Triolo F.
Title: A quality risk management model approach for cell therapy manufacturing.
Summary: International regulatory authorities view risk management as an essential production need for the development of innovative, somatic cell-based therapies in regenerative medicine. The available risk management guidelines, however, provide little guidance on specific risk analysis approaches and procedures applicable in clinical cell therapy manufacturing. This raises a number of problems. Cell manufacturing is a poorly automated process, prone to operator-introduced variations, and affected by heterogeneity of the processed organs/tissues and lot-dependent variability of reagent (e.g., collagenase) efficiency. In this study, the principal challenges faced in a cell-based product manufacturing context (i.e., high dependence on human intervention and absence of reference standards for acceptable risk levels) are identified and addressed, and a risk management model approach applicable to manufacturing of cells for clinical use is described for the first time. The use of the heuristic and pseudo-quantitative failure mode and effect analysis/failure mode and critical effect analysis risk analysis technique associated with direct estimation of severity, occurrence, and detection is, in this specific context, as effective as, but more efficient than, the analytic hierarchy process. Moreover, a severity/occurrence matrix and Pareto analysis can be successfully adopted to identify priority failure modes on which to act to mitigate risks. The application of this approach to clinical cell therapy manufacturing in regenerative medicine is also discussed.
Authors: Ambrosio F, Wolf SL, Delitto A, Fitzgerald GK, Badylak SF, Boninger ML, Russell AJ.
Title: The emerging relationship between regenerative medicine and physical therapeutics.
Summary: Dramatic changes in the health care landscape over the next few decades undoubtedly will affect rehabilitation specialists’ practice. In the multidisciplinary field of regenerative medicine, cell, tissue, or organ substitutes are used to enhance the healing potential of the body. Given that the restoration of normal functioning of injured or diseased tissues is expected to be the ultimate goal of these therapies, the future of regenerative medicine is, undeniably, tightly intertwined with that of rehabilitation. Rehabilitation specialists not only must be aware of cutting-edge medical advances as they relate to regenerative medicine but also must work closely with basic scientists to guide the development of clinically relevant protocols. The purposes of this article are to provide a current perspective on biological approaches to the management of musculoskeletal disorders and to highlight the needed integration of physical therapeutics with regenerative medicine.
Title: Optical coherence tomography detection of subclinical traumatic cartilage injury.
Summary: OBJECTIVES: Posttraumatic arthritis is a major cause of disability. Current clinical imaging modalities are unable to reliably evaluate articular cartilage damage before surface breakdown, when potentially reversible changes are occurring. Optical coherence tomography (OCT) is a nondestructive imaging technology that can detect degenerative changes in articular cartilage with an intact surface. This study tests the hypothesis that OCT detects acute articular cartilage injury after impact at energy levels resulting in chondrocyte death and microstructural changes, but insufficient to produce macroscopic surface damage.
Authors: He W, Nieponice A, Soletti L, Hong Y, Gharaibeh B, Crisan M, Usas A, Peault B, Huard J, Wagner WR, Vorp DA.
Title: Pericyte-based human tissue engineered vascular grafts
Summary: The success of small-diameter tissue engineered vascular grafts (TEVGs) greatly relies on an appropriate cell source and an efficient cellular delivery and carrier system. Pericytes have recently been shown to express mesenchymal stem cell features. Their relative availability and multipotentiality make them a promising candidate for TEVG applications. The objective of this study was to incorporate pericytes into a biodegradable scaffold rapidly, densely and efficiently, and to assess the efficacy of the pericyte-seeded scaffold in vivo. Bi-layered elastomeric poly(ester-urethane)urea scaffolds (length = 10 mm; inner diameter = 1.3 mm) were bulk seeded with 3 x 10(6) pericytes using a customized rotational vacuum seeding device in less than 2 min (seeding efficiency > 90%). The seeded scaffolds were cultured in spinner flasks for 2 days and then implanted into Lewis rats as aortic interposition grafts for 8 weeks. Results showed pericytes populated the porous layer of the scaffolds evenly and maintained their original phenotype after the dynamic culture. After implantation, pericyte-seeded TEVGs showed a significant higher patency rate than the unseeded control: 100% versus 38% (p < 0.05). Patent pericyte-seeded TEVGs revealed extensive tissue remodeling with collagen and elastin present. The remodeled tissue consisted of multiple layers of alpha-smooth muscle actin- and calponin-positive cells, and a von Willebrand factor-positive monolayer in the lumen. These results demonstrate the feasibility of a pericyte-based TEVG and suggest that the pericytes play a role in maintaining patency of the TEVG as an arterial conduit.
Authors: Cherra SJ 3rd, Kulich SM, Uechi G, Balasubramani M, Mountzouris J, Day BW, Chu CT
Title: Regulation of the autophagy protein LC3 by phosphorylation
Summary: Macroautophagy is a major catabolic pathway that impacts cell survival, differentiation, tumorigenesis, and neurodegeneration. Although bulk degradation sustains carbon sources during starvation, autophagy contributes to shrinkage of differentiated neuronal processes. Identification of autophagy-related genes has spurred rapid advances in understanding the recruitment of microtubule-associated protein 1 light chain 3 (LC3) in autophagy induction, although braking mechanisms remain less understood. Using mass spectrometry, we identified a direct protein kinase A (PKA) phosphorylation site on LC3 that regulates its participation in autophagy. Both metabolic (rapamycin) and pathological (MPP(+)) inducers of autophagy caused dephosphorylation of endogenous LC3. The pseudophosphorylated LC3 mutant showed reduced recruitment to autophagosomes, whereas the nonphosphorylatable mutant exhibited enhanced puncta formation. Finally, autophagy-dependent neurite shortening induced by expression of a Parkinson disease-associated G2019S mutation in leucine-rich repeat kinase 2 was inhibited by dibutyryl-cyclic adenosine monophosphate, cytoplasmic expression of the PKA catalytic subunit, or the LC3 phosphorylation mimic. These data demonstrate a role for phosphorylation in regulating LC3 activity.
Title: Cancerous stem cells: deviant stem cells with cancer-causing misbehavior
Summary: Stem cells maintain homeostasis in adult tissues via self-renewal and generation of terminally differentiated cells. Alterations in this intricate balance can result in disease. It has become increasingly evident that cancer can be initiated at the level of stem cells. Therefore, understanding what causes stem cells to become cancerous may lead to new therapeutic approaches. Multiple signaling pathways ultimately affect stem cell survival and proliferation, thus maintaining homeostasis in the gut. Changes in these pathways could perturb normal stem cell behavior, leading to cancerous stem cells. In addition, cancerous stem cells show resistance to current therapies and may lead to a dangerous selection process resulting in recurrence and metastasis. Genomic instability, the driving force of mutation and resistance, may give cancerous stem cells an adaptive advantage, especially when subjected to cancer therapies. Targeting the unique characteristics of cancerous stem cells to promote either terminal differentiation or destruction would effectively eradicate cancer and improve patient care and survival.
Authors: Antaki JF, Ricci MR, Verkaik JE, Snyder ST, Maul TM, Kim J, Paden DB, Kameneva MV, Paden BE, Wearden PD, Borovetz HS
Title: PediaFlow Maglev Ventricular Assist Device: A Prescriptive Design Approach
Summary: This report describes a multi-disciplinary program to develop a pediatric blood pump, motivated by the critical need to treat infants and young children with congenital and acquired heart diseases. The unique challenges of this patient population require a device with exceptional biocompatibility, miniaturized for implantation up to 6 months. This program implemented a collaborative, prescriptive design process, whereby mathematical models of the governing physics were coupled with numerical optimization to achieve a favorable compromise among several competing design objectives. Computational simulations of fluid dynamics, electromagnetics, and rotordynamics were performed in two stages: first using reduced-order formulations to permit rapid optimization of the key design parameters; followed by rigorous CFD and FEA simulations for calibration, validation, and detailed optimization. Over 20 design configurations were initially considered, leading to three pump topologies, judged on the basis of a multi-component analysis including criteria for anatomic fit, performance, biocompatibility, reliability, and manufacturability. This led to fabrication of a mixed-flow magnetically levitated pump, the PF3, having a displaced volume of 16.6 cc, approximating the size of a AA battery and producing a flow capacity of 0.3-1.5 L/min. Initial in vivo evaluation demonstrated excellent hemocompatibility after 72 days of implantation in an ovine. In summary, combination of prescriptive and heuristic design principles have proven effective in developing a miniature magnetically levitated blood pump with excellent performance and biocompatibility, suitable for integration into chronic circulatory support system for infants and young children; aiming for a clinical trial within 3 years.
Authors: Gangadharan B. Sajithlala, Kristi Rothermunda, Fang Zhangb, David J. Dabbsc, Jean J. Latimer, Stephen G. Grant, Edward V. Prochownika
Title: Permanently Blocked Stem Cells Derived from Breast Cancer Cell Lines
Summary: Cancer stem cells (CSCs) are thought to be resistant to standard chemotherapeutic drugs and the inimical conditions of the tumor microenvironment. Obtaining CSCs in sufficient quantities and maintaining their undifferentiated state have been major hurdles to their further characterization and to the identification of new pharmaceuticals that preferentially target these cells. We describe here the tagging of CSC-like populations from four human breast cancer cell lines with green fluorescent protein (GFP) under the control of the Oct3/4 stem cell-specific promoter. As expected, GFP was expressed by the CSC-enriched populations. An unanticipated result, however, was that these cells remained blocked in a CSC-like state and tended to be resistant to chemotherapeutic drugs as well as acidotic and hypoxic conditions. These CSC-like cells possessed several other in vitro attributes of CSCs and were able to reproducibly generate tumors in immunocompromised mice from as few as 100 cells. Moreover, the tumors derived from these cells were comprised almost exclusively of pure CSCs. The ability of the Oct3/4 promoter to block CSC differentiation underscores its potential general utility for obtaining highly purified CSC populations, although the mechanism by which it does so remains undefined and subject to further study. Nonetheless, such stable cell lines should be extremely valuable tools for studying basic questions pertaining to CSC biology and for the initial identification of novel CSC-specific chemotherapeutic agents, which can then be verified in primary CSCs.
Authors: Nathaniel T. Remlinger, Caitlin A. Czajka, Mark E. Juhas, David A. Vorp, Donna B. Stolz, Stephen F. Badylak, Sebastien Gilbert, Thomas W. Gilbert
Title: Hydrated xenogeneic decellularized tracheal matrix as a scaffold for tracheal reconstruction
Summary: Tracheal injury is a rare but complex problem. Primary tracheal reconstructions are commonly performed, but complications such as tension and inadequate vascular supply limit the length of surgical resection. The objective of the present study was to determine whether a hydrated, decellularized porcine tracheal extracellular matrix showed the potential to serve as a functional tracheal replacement graft. Porcine tracheas were decellularized and evaluated to characterize their biochemical composition and biomechanical behavior. Hydrated decellularized tracheal matrix (HDTM) grafts (>5 cm) were implanted heterotopically beneath the strap muscle and wrapped in the omentum in a canine model for 2 and 8 weeks followed by histologic and mechanical analysis. HDTM patches (2 x 3 cm) were also used in a patch tracheoplasty model. The repair site was evaluated bronchoscopically and radiographically, and the grafts were analyzed by histologic methods to evaluate epithelialization and persistence of the cartilage rings. The present study showed that HDTM maintains mechanical characteristics necessary for function under physiologic loading conditions even after 8 weeks of heterotopic implantation. After orthotopic implantation, the grafts were shown to support development of a columnar, pseudostratified, ciliated epithelium, but the cartilage structures showed histologic evidence of degradation and limited new cartilage formation. The results of the study showed tracheal ECM scaffolds support the formation of site-specific epithelium and provide sufficient mechanical integrity withstand physiologic pressures in the short-term. However, for long-term success, it appears that pre-implantation to allow vascularization or preseeding of the graft with chondrocytes will be necessary. Copyright 2010 Elsevier Ltd. All rights reserved.
Authors: Rajaie Namas, Ali Ghuma, Andres Torres, Patricio Polanco, Hernando Gomez, Derek Barclay, Lisa Gordon, Sven Zenker, Hyung Kook Kim, Linda Hermus, Ruben Zamora, Matthew R. Rosengart, Gilles Clermont, Andrew Peitzman, Timothy R. Billiar, Juan Ochoa, Michael R. Pinsky, Juan Carlos Puyana, Yoram Vodovotz
Title: An Adequately Robust Early TNF-a Response Is a Hallmark of Survival Following Trauma/Hemorrhage
Summary: Efforts toward creating artificial cells are shedding light on how life may have emerged. The concept of emergence in the physical and biological sciences is an elusive one. The term refers to phenomena in which the complexity of structures or behaviors in systems with many interacting components exceeds that predicted from knowledge of the individual components and the forces between them.
Title: Cell derived hierarchical assembly of a novel phosphophoryn-based biomaterial.
Summary: Phosphophoryn (PP) is an acidic phosphoprotein belonging to the small integrin-bindingligand N-linked glycoprotein (SIBLING) protein family. PP is highly phosphorylated with approximately 200 phosphates per molecule and has a high affinity for calcium. The aim of this manuscript is to demonstrate that PP has the ability to self-assemble when it is overexpressed in a mammalian cell in the presence of calcium. Our data show that when PP is overexpressed using an adenovirus, the self-assembly occurs in the endoplasmic reticulum (ER) which contains high calcium concentration.
Authors: Santiago LY, Clavijo-Alvarez J, Brayfield C, Rubin JP, Marra KG
Title: Delivery of adipose-derived precursor cells for peripheral nerve repair
Summary: To test the hypothesis that the transplantation of adipose precursor cells (APCs) improves nerve regeneration and functional recovery, human APCs were transplanted into the lumen of a nerve guide in a 6-mm unilateral sciatic nerve defect in athymic rats. The three control groups for the study were biodegradable, polycaprolactone-based nerve conduit without APCs, autograft, and empty defect. Behavioral tests were performed every 3 weeks, and the sciatic functional index (SFI) was calculated based on measurements from the hindlimb prints.
Authors: El-Kurdi MS, Hong Y, Stankus JJ, Soletti L, Wagner WR, Vorp DA.
Title: Transient elastic support for vein grafts using a constricting microfibrillar polymer wrap.
Summary: Arterial vein grafts (AVGs) often fail due to intimal hyperplasia, thrombosis, or accelerated atherosclerosis. Various approaches have been proposed to address AVG failure, including delivery of temporary mechanical support, many of which could be facilitated by perivascular placement of a biodegradable polymer wrap. The purpose of this work was to demonstrate that a polymer wrap can be applied to vein segments without compromising viability/function, and to demonstrate one potential application, i.e., gradually imposing the mid-wall circumferential wall stress (CWS) in wrapped veins exposed to arterial levels of pressure. Poly(ester urethane)urea, collagen, and elastin were combined in solution, and then electrospun onto freshly-excised porcine internal jugular vein segments. Tissue viability was assessed via Live/Dead staining for necrosis, and vasomotor challenge with epinephrine and sodium nitroprusside for functionality. Wrapped vein segments were also perfused for 24h within an ex vivo vascular perfusion system under arterial conditions (pressure = 120/80 mmHg; flow = 100 mL/min), and CWS was calculated every hour. Our results showed that the electrospinning process had no deleterious effects on tissue viability, and that the mid-wall CWS vs. time profile could be dictated through the composition and degradation of the electrospun wrap. This may have important clinical applications by enabling the engineering of an improved AVG.
Authors: Stergios Moschos, Maja Mandic, John Kirkwood, Walter Storkus, and Michael Lotze
Title: Current and Future Considerations in the Use of Mechanical Circulatory Support Devices
Summary: Heart failure (HF) is a major public health problem in the United States, and its prevalence is likely to increase with the aging U.S. population. Mechanical circulatory support (MCS) utilizing bladder-based blood pumps generating pulsatile flow has been reserved for patients with severe HF failing medical therapy. As MCS technology has advanced to include rotary blood pumps, so has our understanding of the biological and clinical responses to MCS, which in turn has altered the risk/benefit profile of this therapy. This may lead to paradigm shifts in device usage from support of end-stage HF to temporary support for recovery of cardiac function and earlier usage, to, ultimately, prevention of disease progression. This review serves to explore the current state and future opportunities of MCS within our larger understanding of the epidemiology, pathophysiology, and treatment options for HF.
Authors: Mihaela Crisan, Solomon Yap, Louis Casteilla, Chien-Wen Chen, Mirko
Corselli, Tea Soon Park, Gabriella Andriolo, Bin Sun, Bo Zheng, Li Zhang,
Cyrille Norotte, Pang-Ning Teng, Jeremy Traas, Rebecca Schugar, Bridget M. Deasy, Stephen Badylak, Hans-Jörg Bűhring, Jean-Paul Giacobino, Lorenza Lazzari, Johnny Huard and Bruno Péault
Title: A Perivascular Origin for Mesenchymal Stem Cells in Multiple Human Organs
Summary: Mesenchymal stem cells (MSC), the archetypal multipotent progenitor cells derived in cultures of developed organs, are of unknown identity and native distribution. We have prospectively identified perivascular cells, principally pericytes, in multiple human organs including skeletal muscle, pancreas, adipose tissue and placenta, on CD146, NG2 and PDGF-Rβ expression and absence of hematopoietic, endothelial and myogenic cell markers. Perivascular cells purified from skeletal muscle or nonmuscle tissues were myogenic in culture and in vivo. Irrespective of their tissue origin, long-term cultured perivascular cells retained myogenicity, exhibited, at the clonal level, osteogenic, chondrogenic and adipogenic potentials, expressed mesenchymal stem cell markers and migrated in a culture model of chemotaxis. Expression of MSC markers was also detected at the surface of native, non-cultured perivascular cells. Thus, blood vessel walls harbor a reserve of progenitor cells that may be integral to the origin of the elusive MSC and other related adult stem cells.