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Carvalho-Oliveira M, Valdivia E, Blasczyk R, Figueiredo C. Immunogenetics of xenotransplantation. Int J Immunogenet 2021; 48:120-134. [PMID: 33410582 DOI: 10.1111/iji.12526] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/06/2020] [Accepted: 12/21/2020] [Indexed: 02/07/2023]
Abstract
Xenotransplantation may become the highly desired solution to close the gap between the availability of donated organs and number of patients on the waiting list. In recent years, enormous progress has been made in the development of genetically engineered donor pigs. The introduced genetic modifications showed to be efficient in prolonging xenograft survival. In this review, we focus on the type of immune responses that may target xeno-organs after transplantation and promising immunogenetic modifications that show a beneficial effect in ameliorating or eliminating harmful xenogeneic immune responses. Increasing histocompatibility of xenografts by eliminating genetic discrepancies between species will pave their way into clinical application.
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Affiliation(s)
- Marco Carvalho-Oliveira
- Institute of Transfusion Medicine and Transplant Engineering, Hannover Medical School, Hannover, Germany.,TRR127 - Biology of Xenogeneic Cell and Organ Transplantation - from bench to bedside, Hannover, Germany
| | - Emilio Valdivia
- Institute of Transfusion Medicine and Transplant Engineering, Hannover Medical School, Hannover, Germany
| | - Rainer Blasczyk
- Institute of Transfusion Medicine and Transplant Engineering, Hannover Medical School, Hannover, Germany
| | - Constanca Figueiredo
- Institute of Transfusion Medicine and Transplant Engineering, Hannover Medical School, Hannover, Germany.,TRR127 - Biology of Xenogeneic Cell and Organ Transplantation - from bench to bedside, Hannover, Germany
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2
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Messina A, Luce E, Hussein M, Dubart-Kupperschmitt A. Pluripotent-Stem-Cell-Derived Hepatic Cells: Hepatocytes and Organoids for Liver Therapy and Regeneration. Cells 2020; 9:cells9020420. [PMID: 32059501 PMCID: PMC7072243 DOI: 10.3390/cells9020420] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 02/04/2020] [Accepted: 02/10/2020] [Indexed: 12/19/2022] Open
Abstract
The liver is a very complex organ that ensures numerous functions; it is thus susceptible to multiple types of damage and dysfunction. Since 1983, orthotopic liver transplantation (OLT) has been considered the only medical solution available to patients when most of their liver function is lost. Unfortunately, the number of patients waiting for OLT is worryingly increasing, and extracorporeal liver support devices are not yet able to counteract the problem. In this review, the current and expected methodologies in liver regeneration are briefly analyzed. In particular, human pluripotent stem cells (hPSCs) as a source of hepatic cells for liver therapy and regeneration are discussed. Principles of hPSC differentiation into hepatocytes are explored, along with the current limitations that have led to the development of 3D culture systems and organoid production. Expected applications of these organoids are discussed with particular attention paid to bio artificial liver (BAL) devices and liver bio-fabrication.
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Affiliation(s)
- Antonietta Messina
- INSERM unité mixte de recherche (UMR_S) 1193, F-94800 Villejuif, France; (A.M.)
- UMR_S 1193, Université Paris-Sud/Paris-Saclay, F-94800 Villejuif, France
- Département Hospitalo-Universitaire (DHU) Hépatinov, F-94800 Villejuif, France
| | - Eléanor Luce
- INSERM unité mixte de recherche (UMR_S) 1193, F-94800 Villejuif, France; (A.M.)
- UMR_S 1193, Université Paris-Sud/Paris-Saclay, F-94800 Villejuif, France
- Département Hospitalo-Universitaire (DHU) Hépatinov, F-94800 Villejuif, France
| | - Marwa Hussein
- INSERM unité mixte de recherche (UMR_S) 1193, F-94800 Villejuif, France; (A.M.)
- UMR_S 1193, Université Paris-Sud/Paris-Saclay, F-94800 Villejuif, France
- Département Hospitalo-Universitaire (DHU) Hépatinov, F-94800 Villejuif, France
| | - Anne Dubart-Kupperschmitt
- INSERM unité mixte de recherche (UMR_S) 1193, F-94800 Villejuif, France; (A.M.)
- UMR_S 1193, Université Paris-Sud/Paris-Saclay, F-94800 Villejuif, France
- Département Hospitalo-Universitaire (DHU) Hépatinov, F-94800 Villejuif, France
- Correspondence: ; Tel.: +33-145595138
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3
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Crane AT, Aravalli RN, Asakura A, Grande AW, Krishna VD, Carlson DF, Cheeran MCJ, Danczyk G, Dutton JR, Hackett PB, Hu WS, Li L, Lu WC, Miller ZD, O'Brien TD, Panoskaltsis-Mortari A, Parr AM, Pearce C, Ruiz-Estevez M, Shiao M, Sipe CJ, Toman NG, Voth J, Xie H, Steer CJ, Low WC. Interspecies Organogenesis for Human Transplantation. Cell Transplant 2019; 28:1091-1105. [PMID: 31426664 PMCID: PMC6767879 DOI: 10.1177/0963689719845351] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Blastocyst complementation combined with gene editing is an emerging approach in the
field of regenerative medicine that could potentially solve the worldwide problem of organ
shortages for transplantation. In theory, blastocyst complementation can generate fully
functional human organs or tissues, grown within genetically engineered livestock animals.
Targeted deletion of a specific gene(s) using gene editing to cause deficiencies in organ
development can open a niche for human stem cells to occupy, thus generating human
tissues. Within this review, we will focus on the pancreas, liver, heart, kidney, lung,
and skeletal muscle, as well as cells of the immune and nervous systems. Within each of
these organ systems, we identify and discuss (i) the common causes of organ failure; (ii)
the current state of regenerative therapies; and (iii) the candidate genes to knockout and
enable specific exogenous organ development via the use of blastocyst complementation. We
also highlight some of the current barriers limiting the success of blastocyst
complementation.
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Affiliation(s)
- Andrew T Crane
- Department of Neurosurgery, University of Minnesota, Minneapolis, USA
| | - Rajagopal N Aravalli
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, USA
| | - Atsushi Asakura
- Stem Cell Institute, University of Minnesota, Minneapolis, USA.,Department of Neurology, University of Minnesota, Minneapolis, USA
| | - Andrew W Grande
- Department of Neurosurgery, University of Minnesota, Minneapolis, USA
| | | | | | - Maxim C-J Cheeran
- Department of Veterinary Population Medicine, University of Minnesota, St. Paul, USA
| | - Georgette Danczyk
- Department of Neurosurgery, University of Minnesota, Minneapolis, USA
| | - James R Dutton
- Stem Cell Institute, University of Minnesota, Minneapolis, USA.,Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, USA
| | - Perry B Hackett
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, USA
| | - Wei-Shou Hu
- Department of Chemical Engineering and Material Science, University of Minnesota, Minneapolis, USA
| | - Ling Li
- Department of Experimental and Clinical Pharmacology, University of Minnesota, Minneapolis, USA
| | - Wei-Cheng Lu
- Department of Neurosurgery, University of Minnesota, Minneapolis, USA
| | - Zachary D Miller
- Department of Neurosurgery, University of Minnesota, Minneapolis, USA
| | - Timothy D O'Brien
- Stem Cell Institute, University of Minnesota, Minneapolis, USA.,Department of Veterinary Population Medicine, University of Minnesota, St. Paul, USA
| | | | - Ann M Parr
- Department of Neurosurgery, University of Minnesota, Minneapolis, USA.,Stem Cell Institute, University of Minnesota, Minneapolis, USA
| | - Clairice Pearce
- Department of Neurosurgery, University of Minnesota, Minneapolis, USA
| | | | - Maple Shiao
- Department of Neurosurgery, University of Minnesota, Minneapolis, USA
| | | | - Nikolas G Toman
- Department of Neurosurgery, University of Minnesota, Minneapolis, USA
| | - Joseph Voth
- Department of Neurosurgery, University of Minnesota, Minneapolis, USA
| | - Hui Xie
- Department of Neurosurgery, University of Minnesota, Minneapolis, USA
| | - Clifford J Steer
- Stem Cell Institute, University of Minnesota, Minneapolis, USA.,Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, USA.,Department of Medicine, University of Minnesota, Minneapolis, USA
| | - Walter C Low
- Department of Neurosurgery, University of Minnesota, Minneapolis, USA.,Stem Cell Institute, University of Minnesota, Minneapolis, USA
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4
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Peloso A, Citro A, Zoro T, Cobianchi L, Kahler-Quesada A, Bianchi CM, Andres A, Berishvili E, Piemonti L, Berney T, Toso C, Oldani G. Regenerative Medicine and Diabetes: Targeting the Extracellular Matrix Beyond the Stem Cell Approach and Encapsulation Technology. Front Endocrinol (Lausanne) 2018; 9:445. [PMID: 30233489 PMCID: PMC6127205 DOI: 10.3389/fendo.2018.00445] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 07/18/2018] [Indexed: 12/20/2022] Open
Abstract
According to the Juvenile Diabetes Research Foundation (JDRF), almost 1. 25 million people in the United States (US) have type 1 diabetes, which makes them dependent on insulin injections. Nationwide, type 2 diabetes rates have nearly doubled in the past 20 years resulting in more than 29 million American adults with diabetes and another 86 million in a pre-diabetic state. The International Diabetes Ferderation (IDF) has estimated that there will be almost 650 million adult diabetic patients worldwide at the end of the next 20 years (excluding patients over the age of 80). At this time, pancreas transplantation is the only available cure for selected patients, but it is offered only to a small percentage of them due to organ shortage and the risks linked to immunosuppressive regimes. Currently, exogenous insulin therapy is still considered to be the gold standard when managing diabetes, though stem cell biology is recognized as one of the most promising strategies for restoring endocrine pancreatic function. However, many issues remain to be solved, and there are currently no recognized treatments for diabetes based on stem cells. In addition to stem cell resesarch, several β-cell substitutive therapies have been explored in the recent era, including the use of acellular extracellular matrix scaffolding as a template for cellular seeding, thus providing an empty template to be repopulated with β-cells. Although this bioengineering approach still has to overcome important hurdles in regards to clinical application (including the origin of insulin producing cells as well as immune-related limitations), it could theoretically provide an inexhaustible source of bio-engineered pancreases.
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Affiliation(s)
- Andrea Peloso
- Division of Abdominal Surgery, Department of Surgery, Faculty of Medicine, University of Geneva, Geneva, Switzerland
- HepatoPancreato-Biliary Centre, Geneva University Hospitals, Geneva, Switzerland
| | - Antonio Citro
- San Raffaele Diabetes Research Institute, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Tamara Zoro
- Department of General Surgery, IRCCS Policlinico San Matteo, Pavia, Italy
- Department of Clinical, Surgical, Diagnostic and Paediatric Sciences, University of Pavia, Pavia, Italy
| | - Lorenzo Cobianchi
- Department of General Surgery, IRCCS Policlinico San Matteo, Pavia, Italy
- Department of Clinical, Surgical, Diagnostic and Paediatric Sciences, University of Pavia, Pavia, Italy
| | - Arianna Kahler-Quesada
- Division of Abdominal Surgery, Department of Surgery, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Carlo M. Bianchi
- Department of General Surgery, IRCCS Policlinico San Matteo, Pavia, Italy
- Department of Clinical, Surgical, Diagnostic and Paediatric Sciences, University of Pavia, Pavia, Italy
| | - Axel Andres
- Division of Abdominal Surgery, Department of Surgery, Faculty of Medicine, University of Geneva, Geneva, Switzerland
- HepatoPancreato-Biliary Centre, Geneva University Hospitals, Geneva, Switzerland
| | - Ekaterine Berishvili
- Cell Isolation and Transplantation Center, University of Geneva, Geneva, Switzerland
- Institute of Medical Research, Ilia State University, Tbilisi, Georgia
| | - Lorenzo Piemonti
- San Raffaele Diabetes Research Institute, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Thierry Berney
- Cell Isolation and Transplantation Center, University of Geneva, Geneva, Switzerland
| | - Christian Toso
- Division of Abdominal Surgery, Department of Surgery, Faculty of Medicine, University of Geneva, Geneva, Switzerland
- HepatoPancreato-Biliary Centre, Geneva University Hospitals, Geneva, Switzerland
| | - Graziano Oldani
- Division of Abdominal Surgery, Department of Surgery, Faculty of Medicine, University of Geneva, Geneva, Switzerland
- HepatoPancreato-Biliary Centre, Geneva University Hospitals, Geneva, Switzerland
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5
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Peloso A, Ferrario J, Maiga B, Benzoni I, Bianco C, Citro A, Currao M, Malara A, Gaspari A, Balduini A, Abelli M, Piemonti L, Dionigi P, Orlando G, Maestri M. Creation and implantation of acellular rat renal ECM-based scaffolds. Organogenesis 2016; 11:58-74. [PMID: 26186418 PMCID: PMC4594518 DOI: 10.1080/15476278.2015.1072661] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Kidney transplantation is the only potentially curative treatment for patient facing end-stage renal disease, and it is now routinely used. Its use is mainly limited by the supply of transplantable donor organs, which far exceeds the demand. Regenerative medicine and tissue engineering offer promising means for overcoming this shortage. In the present study, we developed and validated a protocol for producing acellular rat renal scaffolds. Left kidneys were removed from 26 male Lewis rats (weights: 250–350 g) and decellularized by means of aortic anterograde perfusion with ionic and anionic detergents (Triton X-100 1% and SDS 1%, respectively). 19 scaffolds thus obtained (and contralateral native kidneys as controls) were deeply characterized in order to evaluate the decellularization quality, the preservation of extracellular matrix components and resultant micro-angioarchitecture structure. The other 7 were transplanted into 7 recipient rats that had undergone unilateral nephrectomy. Recipients were sacrificed on post-transplantation day 7 and the scaffolds subjected to histologic studies. The dual-detergent protocol showed, with only 5 h of perfusion per organ, to obtain thoroughly decellularized renal scaffolds consisting almost exclusively of extracellular matrix. Finally the macro- and the microarchitecture of the renal parenchyma were well preserved, and the grafts were implanted with ease. Seven days after transplant, the scaffolds were morphologically intact although all vascular structures were obstructed with thrombi. Production and implantation of acellular rat renal scaffolds is a suitable platform for further studies on regenerative medicine and tissue engineering.
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Affiliation(s)
- Andrea Peloso
- a Dept. of General Surgery ; IRCCS Policlinico San Matteo; Dept. of General Surgery; University of Pavia , Pavia , Italy
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6
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Katari R, Peloso A, Orlando G. Tissue engineering and regenerative medicine: semantic considerations for an evolving paradigm. Front Bioeng Biotechnol 2015; 2:57. [PMID: 25629029 PMCID: PMC4290692 DOI: 10.3389/fbioe.2014.00057] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 11/11/2014] [Indexed: 12/20/2022] Open
Abstract
Tissue engineering (TE) and regenerative medicine (RM) are rapidly evolving fields that are often obscured by a dense cloud of hype and commercialization potential. We find, in the literature and general commentary, that several of the associated terms are casually referenced in varying contexts that ultimately result in the blurring of the distinguishing boundaries which define them. “TE” and “RM” are often used interchangeably, though some experts vehemently argue that they, in fact, represent different conceptual entities. Nevertheless, contemporary scientists have a general idea of the experiments and milestones that can be classified within either or both categories. Given the groundbreaking achievements reported within the past decade and consequent watershed potential of this field, we feel that it would be useful to properly contextualize these terms semantically and historically. In this concept paper, we explore the various definitions proposed in the literature and emphasize that ambiguous terminology can lead to misplaced apprehension. We assert that the central motifs of both concepts have existed within the surgical sciences long before their appearance as terms in the scientific literature.
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Affiliation(s)
- Ravi Katari
- Wake Forest School of Medicine , Winston-Salem, NC , USA
| | - Andrea Peloso
- Wake Forest School of Medicine , Winston-Salem, NC , USA ; General Surgery, Fondazione IRCCS Policlinico San Matteo Pavia, University of Pavia , Pavia , Italy
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7
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Caralt M, Velasco E, Lanas A, Baptista PM. Liver bioengineering: from the stage of liver decellularized matrix to the multiple cellular actors and bioreactor special effects. Organogenesis 2014; 10:250-9. [PMID: 25102189 DOI: 10.4161/org.29892] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Liver bioengineering has been a field of intense research and popular excitement in the past decades. It experiences great interest since the introduction of whole liver acellular scaffolds generated by perfusion decellularization (1-3). Nevertheless, the different strategies developed so far have failed to generate hepatic tissue in vitro bioequivalent to native liver tissue. Even notable novel strategies that rely on iPSC-derived liver progenitor cells potential to self-organize in association with endothelial cells in hepatic organoids are lacking critical components of the native tissue (e.g., bile ducts, functional vascular network, hepatic microarchitecture, etc) (4). Hence, it is vital to understand the strengths and short comes of our current strategies in this quest to re-create liver organogenesis in vitro. To shed some light into these issues, this review describes the different actors that play crucial roles in liver organogenesis and highlights the steps still missing to successfully generate whole livers and hepatic organoids in vitro for multiple applications.
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Affiliation(s)
- Mireia Caralt
- Vall d'Hebron University Hospital; Universitat Autònoma de Barcelona; Barcelona, Spain
| | | | - Angel Lanas
- University of Zaragoza; Zaragoza, Spain; IIS Aragón; CIBERehd; Zaragoza, Spain; Aragon Health Sciences Institute (IACS); Zaragoza, Spain
| | - Pedro M Baptista
- University of Zaragoza; Zaragoza, Spain; IIS Aragón; CIBERehd; Zaragoza, Spain; Aragon Health Sciences Institute (IACS); Zaragoza, Spain
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8
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Salvatori M, Peloso A, Katari R, Soker S, Lerut JP, Stratta RJ, Orlando G. Semi-xenotransplantation: the regenerative medicine-based approach to immunosuppression-free transplantation and to meet the organ demand. Xenotransplantation 2014; 22:1-6. [PMID: 25041180 DOI: 10.1111/xen.12122] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 05/28/2014] [Indexed: 01/16/2023]
Abstract
Although xenografts have always held immeasurable potential as an inexhaustible source of donor organs, immunological barriers and physiological incompatibility have proved to be formidable obstacles to clinical utility. An exciting, new regenerative medicine-based approach termed "semi-xenotransplantation" (SX) seeks to overcome these obstacles by combining the availability and reproducibility of animal organs with the biocompatibility and functionality of human allografts. Compared to conventional xenotransplantation wherein the whole organ is animal-derived, SX grafts are cleansed of their antigenic cellular compartment to produce whole-organ extracellular matrix scaffolds that retain their innate structure and vascular channels. These scaffolds are then repopulated with recipient or donor human stem cells to generate biocompatible semi-xenografts with the structure and function of native human organs. While numerous hurdles must be still overcome in order for SX to become a viable treatment option for end-stage organ failure, the immense potential of SX for meeting the urgent needs for a new source of organs and immunosuppression-free transplantation justifies the interest that the transplant community is committing to the field.
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Palomo AB, Lucas M, Dilley RJ, McLenachan S, Chen FK, Requena J, Sal MF, Lucas A, Alvarez I, Jaraquemada D, Edel MJ. The Power and the Promise of Cell Reprogramming: Personalized Autologous Body Organ and Cell Transplantation. J Clin Med 2014; 3:373-87. [PMID: 26237380 DOI: 10.3390/jcm3020373] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 02/17/2014] [Accepted: 02/19/2014] [Indexed: 12/26/2022] Open
Abstract
Reprogramming somatic cells to induced pluripotent stem cells (iPSCs) or direct reprogramming to desired cell types are powerful and new in vitro methods for the study of human disease, cell replacement therapy, and drug development. Both methods to reprogram cells are unconstrained by the ethical and social questions raised by embryonic stem cells. iPSC technology promises to enable personalized autologous cell therapy and has the potential to revolutionize cell replacement therapy and regenerative medicine. Potential applications of iPSC technology are rapidly increasing in ambition from discrete cell replacement applications to the iPSC assisted bioengineering of body organs for personalized autologous body organ transplant. Recent work has demonstrated that the generation of organs from iPSCs is a future possibility. The development of embryonic-like organ structures bioengineered from iPSCs has been achieved, such as an early brain structure (cerebral organoids), bone, optic vesicle-like structures (eye), cardiac muscle tissue (heart), primitive pancreas islet cells, a tooth-like structure (teeth), and functional liver buds (liver). Thus, iPSC technology offers, in the future, the powerful and unique possibility to make body organs for transplantation removing the need for organ donation and immune suppressing drugs. Whilst it is clear that iPSCs are rapidly becoming the lead cell type for research into cell replacement therapy and body organ transplantation strategies in humans, it is not known whether (1) such transplants will stimulate host immune responses; and (2) whether this technology will be capable of the bioengineering of a complete and fully functional human organ. This review will not focus on reprogramming to iPSCs, of which a plethora of reviews can be found, but instead focus on the latest developments in direct reprogramming of cells, the bioengineering of body organs from iPSCs, and an analysis of the immune response induced by iPSC-derived cells and tissues.
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10
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Abstract
The hair follicle develops from the primitive embryonic epidermis as a result of complex epithelial-mesenchymal interactions. The full follicle, consisting of epithelial cylinders under control of a proximal lying mesenchymal papilla, grows in cycles giving rise to a new hair shaft during each cycle. The ability to cycle endows the follicle with regenerative properties. The evolution of hair follicle engineering began with the recognition in the early 1960's that hair follicles could be transplanted clinically into a foreign site and still grow a shaft typical of the donor site. Since that time, it has been found that the follicular papilla has hair follicle inducing properties and that the hair follicle houses within it epithelial stem cells that can respond to hair inductive signals. These findings have laid the foundation for isolating hair-forming cells, for expanding the cells in culture, and for forming new follicles in vivo.
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Affiliation(s)
- K Stenn
- Aderans Research Institute, Inc.; Philadelphia, Pennsylvania USA
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