Bioprinting: A Further Step to Efective Regenerative Medicine and Tissue Engineering Massimo Conese * Department of Medical and Surgical Sciences, University of Foggia, Foggia 71122, Italy * Corresponding author: Massimo Conese, Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy, Tel.: +39-0881-588019; E-mail: massimo.conese@unifg.it Rec date: Aug 11, 2014, Acc date: Aug 12, 2014, Pub date: Aug 16, 2014 Copyright: © 2014 Conese M. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Keywords: Bio-fabrication Cell printing; Composite organ; Hydrogel; Organ printing; Stem cell therapy; Tree-dimensional printing Editorial Regenerative medicine is a multidisciplinary feld that aims to replace or regenerate human cells, tissues, or organs in order to restore or establish normal function. In this broad sense, this operational defnition should include the ultimate goal of tissue (bio) engineering, i.e. ‘the manufacture of living functional tissues and organs suitable for transplantation in reasonable time scales’ [1]. Te process of regenerating body parts can occur in vivo or ex vivo, and may require stem cells, natural or synthetic cell-supporting scafold materials, bioactive molecules such as for example trophic factors, genetic manipulation, or combinations of all of the above [2]. Te interest in embryonic stem cells has increasingly faded away when the possibility of obtaining pluripotent cells by reprogramming adult somatic cells was achieved. Induced Pluripotent Stem Cells (iPSCs) represents nowadays the most interesting source to be used in regenerative medicine, as, besides pluripotency, they are obtained from the very same patient whom they will administer to and should thus not give any immune reaction [3]. Regenerative medicine and tissue engineering have broad interest as to the application to diferent felds of general surgery, among which skin restoration, heart repair, bioengineering of vessels, kidney, gastroenteric and upper respiratory tracts [4]. Te medical application in this feld started up in 2006 when Atala and colleagues implanted in patients who need cystoplasty bladders engineered ex vivo from the seeding of autologous cells (urothelium and muscle cells) on collagen-polyglycolic acid scafolds as artifcial supporting biomaterial [5]. Another milestone was the manufacture of a trachea from human components. Macchiarini and colleagues transplanted the frst tissue-engineered trachea, utilizing the patient’s own stem cells, into a 30-year old woman with end-stage bronchomalacia, with positive results about respiratory functional tests following the transplantation [6]. Te trachea was denuded and re- seeded with cells from the recipient, i.e. chondrocytes diferentiated from hematopoietic stem/progenitor cells on the outer surface and epithelial cells obtained from the right bronchus on the inner surface. A 5-year follow-up reported the safety and efcacy of this procedure highlighting the function of the tissue-engineered trachea and, importantly, the well-being of the patient [7]. In regenerative medicine, however, the engineering of complex vascularised organs is presently the major challenge to be overcome to guarantee transplantation of organs which are very limited in supply from other individuals [8]. Te use of autologous cellular components with an internal vascular bed will theoretically overcome the two major hurdles in transplantation, namely the shortage of organs and the toxicity deriving from lifelong immunosuppression. Tus, major progress in regenerative therapies will require cell-based products made of many cell types to recapitulate organ metabolic function, and structure to support mechanical function. Recently, this has been partially accomplished by the generation of functional Liver Buds (LBs) from iPSCs [9]. Hepatic endoderm cells from human iPSCs (iPSC-HEs) were cultivated with stromal cell populations, Human Umbilical Vein Endothelial Cells (HUVECs) and human Mesenchymal Stem Cells (MSCs), self-organizing in three-dimensional clusters in vitro and forming iPSC-LBs. In vivo studies demonstrated that: i) transplants became functional by connecting to the host vessels within 48 hours; ii) the formation of functional vasculatures stimulated the maturation of iPSC-LBs into tissue resembling the adult liver; and iii) mesenteric transplantation of iPSC-LBs rescued the drug-induced lethal liver failure model. Tree-dimensional (3D) cell bio-printing is a relatively new engineering tool being used to design 3D cell constructs (rather than cell suspensions) for transplantation therapies. A defnition of bio- printing has been given by Guillemot, Mironov and Nakamura in 2010: ‘the use of computer-aided transfer processes for patterning and assembling living and non-living materials with a prescribed 2D or 3D organization in order to produce bio-engineered structures serving in regenerative medicine, pharmacokinetic and basic cell biology studies’ [10]. An outline of the steps involved in 3D bio-printing is given in Figure 1. Tis technological platform has taken advantage of the one based on 2D inkjet printing. Bio-printing with inkjet technology allows to spray extracellular matrix proteins for providing a defned substrate for cells, elaborate complex cell structures, or to deliver gene and enzymes to cells [11-13]. In its simplest version, 3D bio-printing is aimed at print one layer of cells atop the layer of other cells or scafold biomaterials. On the other hand, 3D bio-printing would be a platform that facilitates construction of complex, multicellular tissues or organs in architectures appropriate for function, and, in one version, it is based on 3D cellular building blocks, instead of liquid inks [12]. Since the beginning of the XXI century, in labs around the world, bioengineers have begun to print frst bacteria, mammalian cells and then prototype organs: heart valves, ears, artifcial bone joints, menisci, blood vessels and skin grafs [10,12,14-21]. Tree factors are leading the evolution of 3D bio-printing: more sophisticated printer, advances in cell therapy and regenerative medicine, and refned Computer- Assisted Design/Computer-Assisted Manufacturing (CAD/CAM) sofware. Moreover, the team may use Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) scans to create a CAD fle of the wound or organs like meniscus. Advancements in Genetic Engineering Conese, Adv Genet Eng 2014, 2:3 http://dx.doi.org/10.4172/2169-0111.1000e112 Editorial Open Access Adv Genet Eng ISSN:2169-0111 AGE, an open access journal Volume 2 • Issue 3 • e112