A brief definition of regenerative medicine

CRISPR technologies for stem cell engineering and regenerative medicine

CRISPR/Cas9 system exploits the concerted action of Cas9 nuclease and programmable single guide RNA (sgRNA), and has been widely used for genome editing. The Cas9 nuclease activity can be abolished by mutation to yield the catalytically deactivated Cas9 (dCas9). Coupling with the customizable sgRNA for targeting, dCas9 can be fused with transcription repressors to inhibit specific gene expression (CRISPR interference, CRISPRi) or fused with transcription activators to activate the expression of gene of interest (CRISPR activation, CRISPRa). Here we introduce the principles and recent advances of these CRISPR technologies, their delivery vectors and review their applications in stem cell engineering and regenerative medicine. In particular, we focus on in vitro stem cell fate manipulation and in vivo applications such as prevention of retinal and muscular degeneration, neural regeneration, bone regeneration, cartilage tissue engineering, as well as treatment of diseases in blood, skin and liver. Finally, the challenges to translate CRISPR to regenerative medicine and future perspectives are discussed and proposed.

Gene Delivery Therapeutics in the Treatment of Periodontitis and Peri-Implantitis: A State of the Art Review

BACKGROUND

Periodontal disease is a chronic inflammatory condition that affects supporting tissues around teeth, resulting in periodontal tissue breakdown. If left untreated, periodontal disease could have serious consequences; this condition is in fact considered as the primary cause of tooth loss. Being highly prevalent among adults, periodontal disease treatment is receiving increased attention from researchers and clinicians. When this condition occurs around dental implants, the disease is termed peri-implantitis. Periodontal regeneration aims at restoring the destroyed attachment apparatus, in order to improve tooth stability and thus reduce disease progression and subsequent periodontal tissue breakdown. Although many biomaterials have been developed to promote periodontal regeneration, they still have their own set of disadvantages. As a result, regenerative medicine has been employed in the periodontal field, not only to overcome the drawbacks of the conventional biomaterials but also to ensure more predictable regenerative outcomes with minimal complications. Regenerative medicine is considered a part of the research field called tissue engineering/regenerative medicine (TE/RM), a translational field combining cell therapy, biomaterial, biomedical engineering and genetics all with the aim to replace and restore tissues or organs to their normal function using in vitro models for in vivo regeneration. In a tissue, cells are responding to different micro-environmental cues and signaling molecules, these biological factors influence cell differentiation, migration and cell responses. A central part of TE/RM therapy is introducing drugs, genetic materials or proteins to induce specific cellular responses in the cells at the site of tissue repair in order to enhance and improve tissue regeneration. In this review, we present the state of art of gene therapy in the applications of periodontal tissue and peri-implant regeneration.

PURPOSE

We aim herein to review the currently available methods for gene therapy, which include the utilization of viral/non-viral vectors and how they might serve as therapeutic potentials in regenerative medicine for periodontal and peri-implant tissues.

Stem cell-based regenerative medicine

Recent developments in the stem cell biology provided new hopes in treatment of diseases and disorders that yet cannot be treated. Stem cells have the potential to differentiate into various cell types in the body during age. These provide new cells for the body as it grows, and replace specialized cells that are damaged. Since mesenchymal stem cells (MSCs) can be easily harvested from the adipose tissue and can also be cultured and expanded in vitro they have become a good target for tissue regeneration. These cells have been widespread used for cell transplantation in animals and also for clinical trials in humans. The purpose of this review is to provide a summary of our current knowledge regarding the important and types of isolated stem cells from different sources of animal models such as horse, pig, goat, dog, rabbit, cat, rat, mice etc. In this regard, due to the widespread use and lot of attention of MSCs, in this review, we will elaborate on use of MSCs in veterinary medicine as well as in regenerative medicine. Based on the studies in this field, MSCs found wide application in treatment of diseases, such as heart failure, wound healing, tooth regeneration etc.

CDKN2B upregulation prevents teratoma formation in multipotent fibromodulin-reprogrammed cells

Tumorigenicity is a well-documented risk to overcome for pluripotent or multipotent cell applications in regenerative medicine. To address the emerging demand for safe cell sources in tissue regeneration, we established a novel, protein-based reprogramming method that does not require genome integration or oncogene activation to yield multipotent fibromodulin (FMOD)-reprogrammed (FReP) cells from dermal fibroblasts. When compared with induced pluripotent stem cells (iPSCs), FReP cells exhibited a superior capability for bone and skeletal muscle regeneration with markedly less tumorigenic risk. Moreover, we showed that the decreased tumorigenicity of FReP cells was directly related to an upregulation of cyclin-dependent kinase inhibitor 2B (CDKN2B) expression during the FMOD reprogramming process. Indeed, sustained suppression of CDKN2B resulted in tumorigenic, pluripotent FReP cells that formed teratomas in vivo that were indistinguishable from iPSC-derived teratomas. These results highlight the pivotal role of CDKN2B in cell fate determination and tumorigenic regulation and reveal an alternative pluripotent/multipotent cell reprogramming strategy that solely uses FMOD protein.

Mitochondrial Akt Signaling Modulated Reprogramming of Somatic Cells

The signaling mechanisms controlling somatic cell reprogramming are not fully understood. In this study, we report a novel role for mitochondrial Akt1 signaling that enhanced somatic cell reprogramming efficiency. The role of mitochondrial Akt1 in somatic cell reprogramming was investigated by transducing fibroblasts with the four reprogramming factors (Oct4, Sox2, Klf4, c-Myc) in conjunction with Mito-Akt1, Mito-dnAkt1, or control virus. Mito-Akt1 enhanced reprogramming efficiency whereas Mito-dnAkt1 inhibited reprogramming. The resulting iPSCs formed embryoid bodies in vitro and teratomas in vivo. Moreover, Oct4 and Nanog promoter methylation was reduced in the iPSCs generated in the presence of Mito-Akt1. Akt1 was activated and translocated into mitochondria after growth factor stimulation in embryonic stem cells (ESCs). To study the effect of mitochondrial Akt in ESCs, a mitochondria-targeting constitutively active Akt1 (Mito-Akt1) was expressed in ESCs. Gene expression profiling showed upregulation of genes that promote stem cell proliferation and survival and down-regulation of genes that promote differentiation. Analysis of cellular respiration indicated similar metabolic profile in the resulting iPSCs and ESCs, suggesting comparable bioenergetics. These findings showed that activation of mitochondrial Akt1 signaling was required during somatic cell reprogramming.

Effects of mineral trioxide aggregate, calcium hydroxide, biodentine and Emdogain on osteogenesis, Odontogenesis, angiogenesis and cell viability of dental pulp stem cells

BACKGROUND

Vital pulp therapy preserves and maintains the integrity and the health of dental pulp tissue that has been injured by trauma, caries or restorative procedures. The enhancement of cells viability and formation of reparative dentine and new blood vessels are vital determinants of the success of direct pulp capping. Therefore, the aims of this study was to evaluate and compare the in vitro osteogenic, odontogenic and angiogenic effects of mineral trioxide aggregate (MTA), calcium hydroxide [Ca(OH)₂], Biodentine and Emdogain on dental pulp stem cells (DPSCs) and examine the effects of the tested materials on cell viability.

METHODS

DPSCs were treated with MTA, Ca(OH)₂, Biodentine or Emdogain. Untreated cells were used as control. The cell viability was measured by MTT assay on day 3. Real-Time PCR with SYBR green was used to quantify the gene expression levels of osteogenic markers (alkaline phosphatase and osteopontin), odontogenic marker (dentin sialophosphoprotein) and angiogenic factor (vascular endothelial growth factor) on day 7 and day 14.

RESULTS

All capping materials showed variable cytotoxicity against DPSCs (77% for Emdogain, 53% for MTA, 26% for Biodentine and 16% for Ca(OH)₂ compared to control (P value < 0.0001). Osteopontin (OPN) and dentin sialophosphoprotein (DSPP) gene expression was increased by all four materials. However, alkaline phosphatase (ALP) was upregulated by all materials except Emdogain. Vascular endothelial growth factor (VEGF) expression was upregulated by all four tested materials except Ca(OH)₂.

CONCLUSIONS

Our results suggest MTA, Biodentine and Emdogain exhibit similar attributes and may score better than Ca(OH)₂. Emdogain could be a promising alternative to MTA and Biodentine in enhancing pulp repair capacity following dental pulp injury. However, further future research is required to assess the clinical outcomes and compare it with the in vitro findings.

Technical Considerations in the Freezing, Low-Temperature Storage and Thawing of Stem Cells for Cellular Therapies

The commercial and clinical development of cellular therapy products will invariably require cryopreservation and frozen storage of cellular starting materials, intermediates and/or final product. Optimising cryopreservation is as important as optimisation of the cell culture process in obtaining maximum yield and a consistent end-product. Suboptimal cryopreservation can lead not only to batch-to-batch variation, lowered cellular functionality and reduced cell yield, but also to the potential selection of subpopulations with genetic or epigenetic characteristics divergent from the original cell line. Regulatory requirements also impact on cryopreservation as these will require a robust and reproducible approach to the freezing, storage and thawing of the product. This requires attention to all aspects of the application of low temperatures: from the choice of freezing container and cryoprotectant, the cooling rate employed and its mode of de-livery, the correct handling of the frozen material during storage and transportation, to the eventual thawing of the product by the end-user. Each of these influences all of the others to a greater or lesser extent and none should be ignored. This paper seeks to provide practical insights and alternative solutions to the technical challenges faced during cryopreservation of cells for use in cellular therapies.

Advanced therapy medicinal products and health technology assessment principles and practices for value-based and sustainable healthcare

BACKGROUND

Advanced therapy medicinal products (ATMPs) are beginning to reach European markets, and questions are being asked about their value for patients and how healthcare systems should pay for them.

OBJECTIVES

To identify and discuss potential challenges of ATMPs in view of current health technology assessment (HTA) methodology-specifically economic evaluation methods-in Europe as it relates to ATMPs, and to suggest potential solutions to these challenges.

METHODS

An Expert Panel reviewed current HTA principles and practices in relation to the specific characteristics of ATMPs.

RESULTS

Three key topics were identified and prioritised for discussion-uncertainty, discounting, and health outcomes and value. The panel discussed that evidence challenges linked to increased uncertainty may be mitigated by collection of follow-on data, use of value of information analysis, and/or outcomes-based contracts. For discount rates, an international, multi-disciplinary forum should be established to consider the economic, social and ethical implications of the choice of rate. Finally, consideration of the feasibility of assessing the value of ATMPs beyond health gain may also be key for decision-making.

CONCLUSIONS

ATMPs face a challenge in demonstrating their value within current HTA frameworks. Consideration of current HTA principles and practices with regards to the specific characteristics of ATMPs and continued dialogue will be key to ensuring appropriate market access.

CLASSIFICATION CODE

I.

Quantitative proteomic analysis of deer antler stem cells as a model of mammalian organ regeneration

The ability to activate and regulate stem cells during wound healing and tissue/organ regeneration is a promising field which could bring innovative approaches to regenerative medicine. The regenerative capacity of invertebrates has been well documented, however in mammals, stem cells that drive organ regeneration are rare. Deer antler is unique in providing a mammalian model of complete organ regeneration based on stem cells. The present study investigated the differentially regulated proteins (DRPs) between different antler stem cell populations (n = 3) using 2D-DIGE. Western blotting was used to validate the proteomics results. Comparative proteomics resulted in protein profiles which were similar for the biological replicates but different between the cells derived from two different stem cell niches involved in antler growth/regeneration and cells derived from facial periosteum. Ninety-two up- and down-regulated proteins were identified by MALDI-TOF MS. The work indicates that the epithelial-mesenchymal transition process may participate in the initiation of antler regeneration including the first stage of scar-less wound healing. Cell mobility is also highly regulated during antler regeneration. Energy and nucleotide metabolism may however be less active in antler regeneration as compared to that in antler generation phase. These results provide new insights into the underlying mechanisms of stem cell-based regeneration of mammalian organs.

Electrospun nanofiber mesh with fibroblast growth factor and stem cells for pelvic floor repair

Surgical outcome following pelvic organ prolapse (POP) repair needs improvement. We suggest a new approach based on a tissue-engineering strategy. In vivo, the regenerative potential of an electrospun biodegradable polycaprolactone (PCL) mesh was studied. Six different biodegradable PCL meshes were evaluated in a full-thickness abdominal wall defect model in 84 rats. The rats were assigned into three groups: (1) hollow fiber PCL meshes delivering two dosages of basic fibroblast growth factor (bFGF), (2) solid fiber PCL meshes with and without bFGF, and (3) solid fiber PCL meshes delivering connective tissue growth factor (CTGF) and rat mesenchymal stem cells (rMSC). After 8 and 24 weeks, we performed a histological evaluation, quantitative analysis of protein content, and the gene expression of collagen-I and collagen-III, and an assessment of the biomechanical properties of the explanted meshes. Multiple complications were observed except from the solid PCL-CTGF mesh delivering rMSC. Hollow PCL meshes were completely degraded after 24 weeks resulting in herniation of the mesh area, whereas the solid fiber meshes were intact and provided biomechanical reinforcement to the weakened abdominal wall. The solid PCL-CTGF mesh delivering rMSC demonstrated improved biomechanical properties after 8 and 24 weeks compared to muscle fascia. These meshes enhanced biomechanical and biochemical properties, demonstrating a great potential of combining tissue engineering with stem cells as a new therapeutic strategy for POP repair. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:48-55, 2020.

Kartogenin and Its Application in Regenerative Medicine

Regenerative medicine refers to the possibility of replacing aged/damaged cells with genetically similar young and functional cells to restore or establish normal function. Kartogenin (KGN), a small heterocyclic, drug-like compound was discovered in 2012, which is strongly associated with regenerative medicine. KGN has been applied in many regenerative fields, including cartilage regeneration and protection, tendon-bone healing, wound healing, and limb development. KGN could facilitate cartilage repair, promote formation of cartilage-like transition zone in tendon-bone junctions, stimulate collagen synthesis for wound healing, and regulate limb development in a coordinated manner. Considering the related mechanism, filamin A/CBFβ/RUNX1, Ihh, and TGFβ/Smad pathways have been reported to involve KGN. Therefore, KGN is proven a promising agent in regenerative medicine; however, studies conducted on the effect of KGN are limited to date and not convictive for long-term use. Further studies are recommended to explore the long-term effect and potential molecular mechanisms of KGN. Our investigations may motivate researchers to expand its applications in different forms and fields.

The impact of transposable element activity on therapeutically relevant human stem cells

Human stem cells harbor significant potential for basic and clinical translational research as well as regenerative medicine. Currently ~ 3000 adult and ~ 30 pluripotent stem cell-based, interventional clinical trials are ongoing worldwide, and numbers are increasing continuously. Although stem cells are promising cell sources to treat a wide range of human diseases, there are also concerns regarding potential risks associated with their clinical use, including genomic instability and tumorigenesis concerns. Thus, a deeper understanding of the factors and molecular mechanisms contributing to stem cell genome stability are a prerequisite to harnessing their therapeutic potential for degenerative diseases. Chemical and physical factors are known to influence the stability of stem cell genomes, together with random mutations and Copy Number Variants (CNVs) that accumulated in cultured human stem cells. Here we review the activity of endogenous transposable elements (TEs) in human multipotent and pluripotent stem cells, and the consequences of their mobility for genomic integrity and host gene expression. We describe transcriptional and post-transcriptional mechanisms antagonizing the spread of TEs in the human genome, and highlight those that are more prevalent in multipotent and pluripotent stem cells. Notably, TEs do not only represent a source of mutations/CNVs in genomes, but are also often harnessed as tools to engineer the stem cell genome; thus, we also describe and discuss the most widely applied transposon-based tools and highlight the most relevant areas of their biomedical applications in stem cells. Taken together, this review will contribute to the assessment of the risk that endogenous TE activity and the application of genetically engineered TEs constitute for the biosafety of stem cells to be used for substitutive and regenerative cell therapies.

A comparative in vitro study of the osteogenic and adipogenic potential of human dental pulp stem cells, gingival fibroblasts and foreskin fibroblasts

Human teeth contain a variety of mesenchymal stem cell populations that could be used for cell-based regenerative therapies. However, the isolation and potential use of these cells in the clinics require the extraction of functional teeth, a process that may represent a significant barrier to such treatments. Fibroblasts are highly accessible and might represent a viable alternative to dental stem cells. We thus investigated and compared the in vitro differentiation potential of human dental pulp stem cells (hDPSCs), gingival fibroblasts (hGFs) and foreskin fibroblasts (hFFs). These cell populations were cultured in osteogenic and adipogenic differentiation media, followed by Alizarin Red S and Oil Red O staining to visualize cytodifferentiation. Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) was performed to assess the expression of markers specific for stem cells (NANOG, OCT-4), osteogenic (RUNX2, ALP, SP7/OSX) and adipogenic (PPAR-γ2, LPL) differentiation. While fibroblasts are more prone towards adipogenic differentiation, hDPSCs exhibit a higher osteogenic potential. These results indicate that although fibroblasts possess a certain mineralization capability, hDPSCs represent the most appropriate cell population for regenerative purposes involving bone and dental tissues.

Tracking Neural Progenitor Cell Migration in the Rodent Brain Using Magnetic Resonance Imaging

The study of neurogenesis and neural progenitor cells (NPCs) is important across the biomedical spectrum, from learning about normal brain development and studying disease to engineering new strategies in regenerative medicine. In adult mammals, NPCs proliferate in two main areas of the brain, the subventricular zone (SVZ) and the subgranular zone, and continue to migrate even after neurogenesis has ceased within the rest of the brain. In healthy animals, NPCs migrate along the rostral migratory stream (RMS) from the SVZ to the olfactory bulb, and in diseased animals, NPCs migrate toward lesions such as stroke and tumors. Here we review how MRI-based cell tracking using iron oxide particles can be used to monitor and quantify NPC migration in the intact rodent brain, in a serial and relatively non-invasive fashion. NPCs can either be labeled directly in situ by injecting particles into the lateral ventricle or RMS, where NPCs can take up particles, or cells can be harvested and labeled in vitro, then injected into the brain. For in situ labeling experiments, the particle type, injection site, and image analysis methods have been optimized and cell migration toward stroke and multiple sclerosis lesions has been investigated. Delivery of labeled exogenous NPCs has allowed imaging of cell migration toward more sites of neuropathology, which may enable new diagnostic and therapeutic opportunities for as-of-yet untreatable neurological diseases.

Bibliographic review on the state of the art of strontium and zinc based regenerative therapies. Recent developments and clinical applications

This review brings up to date the state of the art of strontium and zinc based regenerative therapies, both having a promoting effect on tissue formation and a role inhibiting resorption in musculoskeletal disorders.

Regenerative Medicine Therapies for Rare Diseases

The field of regenerative medicine is growing rapidly with the introduction of new therapies that have the potential to treat and cure serious medical conditions, including rare diseases, for which there are no available treatments. In the United States, the development of novel medical products is regulated and guided by the Food and Drug Administration (FDA). As scientific and technological advances are discovered and adopted by the medical industrial enterprise, the FDA's implementation of policies that create a climate conducive to safe development and rapid availability of novel medical products is one of the pillars which support the Agency's mission of protecting and promoting the public health. With advancements in cell modifications and tissue engineering, innovative creation of biomaterials, adoption of three-dimensional bioprinting, and rapid development of human genome editing technologies, the need for Agency's work in ensuring that its science-based policies remain relevant and helpful in facilitating the availability of new treatments to the most vulnerable populations of patients becomes more pressing than ever before. In December 2016, Congress amended section 506 of the Food, Drug, and Cosmetic (FD&C) Act [21 U.S.C. 356] by adding a new section 506(g), which defines the categories of products considered to be regenerative medicine therapies. As further described by FDA [1], regenerative medicine therapies are considered to include cell therapies, therapeutic tissue engineering products, human cell and tissue products, and combination products using any such therapies, as well as gene therapies, including genetically modified cells that lead to a durable modification of cells or tissues. The development and approval of regenerative medicine therapies are regulated by FDA's Office of Tissues and Advanced Therapies (OTAT) in the Center for Biologics Evaluation and Research (CBER). In this review article, we present practical considerations for investigating regenerative medicine therapies intended for the treatment of rare diseases. The material presented may be useful to researchers who are undertaking the challenging task of finding and delivering new treatments for those in need.

Decision Support Tools for Regenerative Medicine: Systematic Review

BACKGROUND

Decisional tools have demonstrated their importance in informing manufacturing and commercial decisions in the monoclonal antibody domain. Recent approved therapies in regenerative medicine have shown great clinical benefits to patients.

OBJECTIVE

The objective of this review was to investigate what decisional tools are available and what issues and gaps have been raised for their use in regenerative medicine.

METHODS

We systematically searched MEDLINE to identify articles on decision support tools relevant to tissue engineering, and cell and gene therapy, with the aim of identifying gaps for future decisional tool development. We included published studies in English including a description of decisional tools in regenerative medicines. We extracted data using a predesigned Excel table and assessed the data both quantitatively and qualitatively.

RESULTS

We identified 9 articles addressing key decisions in manufacturing and product development challenges in cell therapies. The decision objectives, parameters, assumptions, and solution methods were analyzed in detail. We found that all decisional tools focused on cell therapies, and 6 of the 9 reviews focused on allogeneic cell therapy products. We identified no available tools on tissue-engineering and gene therapy products. These studies addressed key decisions in manufacturing and product development challenges in cell therapies, such as choice of technology, through modeling.

CONCLUSIONS

Our review identified a limited number of decisional tools. While the monoclonal antibodies and biologics decisional tool domain has been well developed and has shown great importance in driving more cost-effective manufacturing processes and better investment decisions, there is a lot to be learned in the regenerative medicine domain. There is ample space for expansion, especially with regard to autologous cell therapies, tissue engineering, and gene therapies. To consider the problem more comprehensively, the full needle-to-needle process should be modeled and evaluated.

Tissue Engineering Therapies Based on Folic Acid and Other Vitamin B Derivatives. Functional Mechanisms and Current Applications in Regenerative Medicine

B-vitamins are a group of soluble vitamins which are cofactors of some of the enzymes involved in the metabolic pathways of carbohydrates, fats and proteins. These compounds participate in a number of functions as cardiovascular, brain or nervous systems. Folic acid is described as an accessible and multifunctional niche component that can be used safely, even combined with other compounds, which gives it high versatility. Also, due to its non-toxicity and great stability, folic acid has attracted much attention from researchers in the biomedical and bioengineering area, with an increasing number of works directed at using folic acid and its derivatives in tissue engineering therapies as well as regenerative medicine. Thus, this review provides an updated discussion about the most relevant advances achieved during the last five years, where folic acid and other vitamins B have been used as key bioactive compounds for enhancing the effectiveness of biomaterials' performance and biological functions for the regeneration of tissues and organs.

Emerging Interventions for Elderly Patients-The Promise of Regenerative Medicine

The impressive increase in lifespan that occurred in the 20th century has driven a boom in age-associated degeneration resulting from senescence. Geriatric syndromes, such as sarcopenia and frailty, do not fall neatly into classical medical definitions of disease because they result from subtle declines in physiological function that occur over many years instead of specific organ-related pathology. These conditions have become more clinically prominent with the aging population and are the focus of research in regenerative medicine. Two major approaches are being pursued: the first targets specific organs that are adversely affected by senescence, and the second targets senescence pathways themselves, with the goal of favorably altering the affected physiology. This review will highlight a few examples of recent applications of both of these approaches to illustrate the potential of the application of a regenerative medicine approach to improve the quality of life and independence in older adults.

Growth Factors and Cell Homing in Dental Tissue Regeneration

Purpose of Review

To summarize current views on the role and therapeutic potential of growth factors (GFs) within endodontic cell homing.

Recent Findings

Cell homing/revitalization techniques aim to regenerate dentin and pulp using endogenous cells. Clinically, revitalization has successfully created new vital tissue in necrotic permanent teeth with an open apex; however, there is no evidence of new odontoblasts, pulp tissue, or predictable extension in root length. Although the response is reparative rather than regenerative, exciting opportunities to improve these biologically-based strategies remain by (1) efficiently sequestering dentin-matrix-components (DMCs) using irrigants and dental materials (2) designing next-generation GF-releasing scaffold materials and (3) utilizing other sources of GF such as cells and plasma-rich plasma and plasma-rich fibrin.

Summary

GFs can promote reparative-dentinogenesis and pulp-like tissue formation. The future development and clinical approval of GF-functionalized-scaffolds is a priority; however, current focus should be to harness DMCs and target the interaction of stem cells and GFs.

Evaluation of willingness to pay per quality-adjusted life year for a cure: A contingent valuation method using a scenario-based survey

Cost-effectiveness is 1 of the most important factors in medicine reimbursement, and social willingness to pay (WTP) can provide evidence for the threshold of cost-effectiveness analysis. Recently, the concept of curative medicines has been introduced, so it is necessary to study their cost-effectiveness. This study aimed to estimate WTP per quality-adjusted life year (QALY) for a cure in the Korean general population.A total of 507 people from the general population, proportionally assigned by sex, age, and region, participated in face-to-face interviews. The contingent valuation survey was conducted with scenarios involving 4 EuroQol-5 dimensions (EQ-5D) with different health statuses. We assumed a treatment that moved the health status of each scenario to perfect health. WTP for 1 year of treatment was derived using a double-bounded format followed by open-ended answers. In the cure scenario, the post-treatment effect continued for a lifetime; in the non-cure scenario, the effect instantly stopped when treatment was terminated. Additionally, prolonged treatment effects lasting 5 and 10 years were added. To identify the factors influencing WTP, a multi-level analysis was performed.WTP per QALY for the non-cure scenario was KRW 15 million/QALY. For the cure scenario, WTP was 2.3 times higher (KRW 35 million/QALY) than in the non-cure scenario. The results for the prolonged treatment effect scenarios were KRW 22 million/QALY and KRW 27 million/QALY, which are 1.4 and 1.8 times higher than the non-cure scenario, respectively. In all scenarios, the statistically significant factors affecting WTP per QALY were higher education, higher household income, and healthcare provider.This study revealed that WTP for a cure treatment was higher than that for non-cure; this higher WTP should be considered in future decision-making regarding curative treatments.

Supramolecular polymeric biomaterials

Polymeric chains crosslinked through supramolecular interactions-directional and reversible non-covalent interactions-compose an emerging class of modular and tunable biomaterials. The choice of chemical moiety utilized in the crosslink affords different thermodynamic and kinetic parameters of association, which in turn illustrate the connectivity and dynamics of the system. These parameters, coupled with the choice of polymeric architecture, can then be engineered to control environmental responsiveness, viscoelasticity, and cargo diffusion profiles, yielding advanced biomaterials which demonstrate rapid shear-thinning, self-healing, and extended release. In this review we examine the relationship between supramolecular crosslink chemistry and biomedically relevant macroscopic properties. We then describe how these properties are currently leveraged in the development of materials for drug delivery, immunology, regenerative medicine, and 3D-bioprinting (253 references).

Organoid technology for brain and therapeutics research

Brain is one of the most complex organs in human. The current brain research is mainly based on the animal models and traditional cell culture. However, the inherent species differences between humans and animals as well as the gap between organ level and cell level make it difficult to study human brain development and associated disorders through traditional technologies. Recently, the brain organoids derived from pluripotent stem cells have been reported to recapitulate many key features of human brain in vivo, for example recapitulating the zone of putative outer radial glia cells. Brain organoids offer a new platform for scientists to study brain development, neurological diseases, drug discovery and personalized medicine, regenerative medicine, and so on. Here, we discuss the progress, applications, advantages, limitations, and prospects of brain organoid technology in neurosciences and related therapeutics.

Factors Influencing the Umbilical Cord Blood Stem Cell Industry: An Evolving Treatment Landscape

Hematopoietic stem cell transplantation (HSCT) is common practice today for life threatening malignant and non-malignant diseases of the blood and immune systems. Umbilical cord blood (UCB) is rich in hematopoietic stem cells (HSCs) and is an attractive alternative to harvesting HSCs from bone marrow or when mobilized into peripheral blood. One of the most appealing attributes of UCB is that it can be banked for future use and hence provides an off-the-shelf solution for patients in urgent need of a transplantation. This has led to the establishment of publicly funded and private UCB banks, as seen by the rapid growth of the UCB industry in the early part of this century. However, from about 2010, the release of UCB units for treatment purposes plateaued and started to decrease year-on-year from 2013 to 2016. Our interest has been to investigate the factors contributing to these changes. Key drivers influencing the UCB industry include the emergence of haploidentical HSCT and the increasing use of UCB units for regenerative medicine purposes. Further influencing this dynamic is the high cost associated with UCB transplantation, the economic impact of sustaining public bank operations and an active private UCB banking sector. We foresee that these factors will continue in a tug-of-war fashion to shape and finally determine the fate of the UCB industry. Stem Cells Translational Medicine 2018 Stem Cells Translational Medicine 2018;7:643-650.

Biomedical Applications of Recombinant Silk-Based Materials

Silk is mostly known as a luxurious textile, which originates from silkworms first cultivated in China. A deeper look into the variety of silk reveals that it can be used for much more, in nature and by humanity. For medical purposes, natural silks were recognized early as a potential biomaterial for surgical threads or wound dressings; however, as biomedical engineering advances, the demand for high-performance, naturally derived biomaterials becomes more pressing and stringent. A common problem of natural materials is their large batch-to-batch variation, the quantity available, their potentially high immunogenicity, and their fast biodegradation. Some of these common problems also apply to silk; therefore, recombinant approaches for producing silk proteins have been developed. There are several research groups which study and utilize various recombinantly produced silk proteins, and many of these have also investigated their products for biomedical applications. This review gives a critical overview over of the results for applications of recombinant silk proteins in biomedical engineering.

Recent Progress in Developing Injectable Matrices for Enhancing Cell Delivery and Tissue Regeneration

Biomaterials are key factors in regenerative medicine. Matrices used for cell delivery are especially important, as they provide support to transplanted cells that is essential for promoting cell survival, retention, and desirable phenotypes. Injectable matrices have become promising and attractive due to their minimum invasiveness and ease of use. Conventional injectable matrices mostly use hydrogel precursor solutions that form solid, cell-laden hydrogel scaffolds in situ. However, these materials are associated with challenges in biocompatibility, shear-induced cell death, lack of control over cellular phenotype, lack of macroporosity and remodeling, and relatively weak mechanical strength. This Progress Report provides a brief overview of recent progress in developing injectable matrices to overcome the limitations of conventional in situ hydrogels. Biocompatible chemistry and shear-thinning hydrogels have been introduced to promote cell survival and retention. Emerging investigations of the effects of matrix properties on cellular function in 3D provide important guidelines for promoting desirable cellular phenotypes. Moreover, several novel approaches are combining injectability with macroporosity to achieve macroporous, injectable matrices for cell delivery.

Genome Editing Redefines Precision Medicine in the Cardiovascular Field

Genome editing is a powerful tool to study the function of specific genes and proteins important for development or disease. Recent technologies, especially CRISPR/Cas9 which is characterized by convenient handling and high precision, revolutionized the field of genome editing. Such tools have enormous potential for basic science as well as for regenerative medicine. Nevertheless, there are still several hurdles that have to be overcome, but patient-tailored therapies, termed precision medicine, seem to be within reach. In this review, we focus on the achievements and limitations of genome editing in the cardiovascular field. We explore different areas of cardiac research and highlight the most important developments: (1) the potential of genome editing in human pluripotent stem cells in basic research for disease modelling, drug screening, or reprogramming approaches and (2) the potential and remaining challenges of genome editing for regenerative therapies. Finally, we discuss social and ethical implications of these new technologies.

Recent Advances in Modified Cellulose for Tissue Culture Applications

Tissue engineering is a rapidly advancing field in regenerative medicine, with much research directed towards the production of new biomaterial scaffolds with tailored properties to generate functional tissue for specific applications. Recently, principles of sustainability, eco-efficiency and green chemistry have begun to guide the development of a new generation of materials, such as cellulose, as an alternative to conventional polymers based on conversion of fossil carbon (e.g., oil) and finding technologies to reduce the use of animal and human derived biomolecules (e.g., foetal bovine serum). Much of this focus on cellulose is due to it possessing the necessary properties for tissue engineering scaffolds, including biocompatibility, and the relative ease with which its characteristics can be tuned through chemical modification to adjust mechanical properties and to introduce various surface modifications. In addition, the sustainability of producing and manufacturing materials from cellulose, as well as its modest cost, makes cellulose an economically viable feedstock. This review focusses specifically on the use of modified cellulose materials for tissue culturing applications. We will investigate recent techniques used to promote scaffold function through physical, biochemical and chemical scaffold modifications, and describe how these have been utilised to reduce reliance on the addition of matrix ligands such as foetal bovine serum.

Cell therapy-processing economics: small-scale microfactories as a stepping stone toward large-scale macrofactories

AIM

Manufacturing methods for cell-based therapies differ markedly from those established for noncellular pharmaceuticals and biologics. Attempts to 'shoehorn' these into existing frameworks have yielded poor outcomes. Some excellent clinical results have been realized, yet emergence of a 'blockbuster' cell-based therapy has so far proved elusive.

MATERIALS & METHODS

The pressure to provide these innovative therapies, even at a smaller scale, remains. In this process, economics research paper, we utilize cell expansion research data combined with operational cost modeling in a case study to demonstrate the alternative ways in which a novel mesenchymal stem cell-based therapy could be provided at small scale.

RESULTS & CONCLUSIONS

This research outlines the feasibility of cell microfactories but highlighted that there is a strong pressure to automate processes and split the quality control cost-burden over larger production batches. The study explores one potential paradigm of cell-based therapy provisioning as a potential exemplar on which to base manufacturing strategy.

Stem Cells Application in Thoracic Surgery: Current Perspective and Future Directions

Two main fields of clinical applications of stem cells in thoracic surgery have been explored: (a) regenerative medicine, that is a branch of translational research in tissue engineering and molecular biology dealing with the replacement, engineering or regeneration of cells, tissues and organs to restore normal function; (b) drug loading and delivery, that is an emerging field proposing stem cells as vectors to deliver anti-cancer agents for targeted therapies.Bronchopleural fistula is a pathological connection between the bronchus and the pleural cavity that may develop after lung resection, thus causing pleural empyema due to colonization by resident airway bacteria; stem cells and regenerative medicine approach can effectively contribute to impaired bronchial healing, thus preventive a septic and ventilator catastrophe.In the field of thoracic oncology, MSC are probably one of the best choice for anticancer drug delivery, emerging as potential experimental approach to malignant mesothelioma treatment.The goal of this review is to focus on clinical applications of stem cell technologies in thoracic surgery, emphasizing regenerative medicine aspects as well as drug loading and delivery in thoracic oncology.

The assessment and appraisal of regenerative medicines and cell therapy products: an exploration of methods for review, economic evaluation and appraisal

BACKGROUND

The National Institute for Health and Care Excellence (NICE) commissioned a 'mock technology appraisal' to assess whether changes to its methods and processes are needed. This report presents the findings of independent research commissioned to inform this appraisal and the deliberations of a panel convened by NICE to evaluate the mock appraisal.

METHODS

Our research included reviews to identify issues, analysis methods and conceptual differences and the relevance of alternative decision frameworks, alongside the development of an exemplar case study of chimeric antigen receptor (CAR) T-cell therapy for treating acute lymphoblastic leukaemia.

RESULTS

An assessment of previous evaluations of regenerative medicines found that, although there were a number of evidential challenges, none was unique to regenerative medicines or was beyond the scope of existing methods used to conceptualise decision uncertainty. Regarding the clinical evidence for regenerative medicines, the issues were those associated with a limited evidence base but were not unique to regenerative medicines: small non-randomised studies, high variation in response and the intervention subject to continuing development. The relative treatment effects generated from single-arm trials are likely to be optimistic unless it is certain that the historical data have accurately estimated the efficacy of the control agent. Pivotal trials may use surrogate end points, which, on average, overestimate treatment effects. To reduce overall uncertainty, multivariate meta-analysis of all available data should be considered. Incorporating indirectly relevant but more reliable (more mature) data into the analysis can also be considered; such data may become available as a result of the evolving regulatory pathways being developed by the European Medicines Agency. For the exemplar case of CAR T-cell therapy, target product profiles (TPPs) were developed, which considered the 'curative' and 'bridging to stem-cell transplantation' treatment approaches separately. Within each TPP, three 'hypothetical' evidence sets (minimum, intermediate and mature) were generated to simulate the impact of alternative levels of precision and maturity in the clinical evidence. Subsequent assessments of cost-effectiveness were undertaken, employing the existing NICE reference case alongside additional analyses suggested within alternative frameworks. The additional exploratory analyses were undertaken to demonstrate how assessments of cost-effectiveness and uncertainty could be impacted by alternative managed entry agreements (MEAs), including price discounts, performance-related schemes and technology leasing. The panel deliberated on the range of TPPs, evidence sets and MEAs, commenting on the likely recommendations for each scenario. The panel discussed the challenges associated with the exemplar and regenerative medicines more broadly, focusing on the need for a robust quantification of the level of uncertainty in the cost-effective estimates and the potential value of MEAs in limiting the exposure of the NHS to high upfront costs and loss associated with a wrong decision.

CONCLUSIONS

It is to be expected that there will be a significant level of uncertainty in determining the clinical effectiveness of regenerative medicines and their long-term costs and benefits, but the existing methods available to estimate the implications of this uncertainty are sufficient. The use of risk sharing and MEAs between the NHS and manufacturers of regenerative medicines should be investigated further.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Anticipating the clinical adoption of regenerative medicine: building institutional readiness in the UK

This perspective paper examines the challenges of implementing regenerative medicine (RM) therapies within hospitals and clinics. Drawing on recent work in the social sciences, the paper highlights dynamics within existing healthcare systems that will present both hindrances and affordances for the implementation of new RM technologies within hospitals and clinics. The paper argues that identifying suitable locations for cell- and gene-therapy treatment centers requires an assessment of their institutional readiness for RM. Some provisional criteria for assessing institutional readiness are outlined, and the paper will suggest that it is necessary to begin developing a program for the phased introduction of RM in the longer term.

Biomaterials for Regenerative Medicine: Historical Perspectives and Current Trends

Biomaterials are key components in tissue engineering and regenerative medicine applications, with the intended purpose of reducing the burden of disease and enhancing the quality of life of a large number of patients. The success of many regenerative medicine strategies, such as cell-based therapies, artificial organs, and engineered living tissues, is highly dependent on the ability to design or produce suitable biomaterials that can support and guide cells during tissue healing and remodelling processes. This chapter presents an overview about basic research concerning the use of different biomaterials for tissue engineering and regenerative medicine applications. Starting from a historical perspective, the chapter introduces the basic principles of designing biomaterials for tissue regeneration approaches. The main focus is set on describing the main classes of biomaterials that have been applied in regenerative medicine, including natural and synthetic polymers, bioactive ceramics, and composites. For each class of biomaterials, some of the most important physicochemical and biological properties are presented. Finally, some challenges and concerns that remain in this field are presented and discussed.

Functional Role of Circular RNA in Regenerative Medicine

Every year, millions of people around the world suffer from different forms of tissue trauma. Regenerative medicine refers to therapy that replaces the injured organ or cells. Stem cells are the frontiers and hotspots of current regenerative medicine research. Circular RNAs (circRNAs) are essential for the early development of many species. It was found that they could guide stem cell differentiation through interacting with certain microRNAs (miRNAs). Based on this concept, it is meaningful to look into how circRNAs influence stem cells and its role in regenerative medicine. In this chapter we will discuss the functional roles of circRNAs in the prevention, repair, or progression of chronic diseases, through the communication between stem cells.

Stem cell therapy clinical research: A regulatory conundrum for academia

The encouraging pace of discovery and development in the field of regenerative medicine holds tremendous potential for bringing therapies to the clinic that may offer meaningful benefit to patients, particularly in diseases with no or suboptimal therapeutic options. Academic researchers will continue to play a critical role in developing concepts and therapies, thus determining whether regenerative medicine will be able to live up to this potential that clearly excites clinicians, researchers and patients alike. This review summarises recent developments in regulatory frameworks across different countries that aim to ensure adequate oversight of the development of regenerative medicine products, which are unique in structural and functional complexity when compared to traditional chemical drugs and fully characterised biological drugs. It discusses the implications of these developments for researchers aiming to make the challenging transition from laboratory to clinical development of these therapies and considers possible pragmatic solutions that could accelerate this process that is essential to maintain research credibility and ensure patient safety.

Mesenchymal Stem Cells: Potential Role in the Treatment of Osteochondral Lesions of the Ankle

Given articular cartilage has a limited repair potential, untreated osteochondral lesions of the ankle can lead to debilitating symptoms and joint deterioration necessitating joint replacement. While a wide range of reparative and restorative surgical techniques have been developed to treat osteochondral lesions of the ankle, there is no consensus in the literature regarding which is the ideal treatment. Tissue engineering strategies, encompassing stem cells, somatic cells, biomaterials, and stimulatory signals (biological and mechanical), have a potentially valuable role in the treatment of osteochondral lesions. Mesenchymal stem cells (MSCs) are an attractive resource for regenerative medicine approaches, given their ability to self-renew and differentiate into multiple stromal cell types, including chondrocytes. Although MSCs have demonstrated significant promise in in vitro and in vivo preclinical studies, their success in treating osteochondral lesions of the ankle is inconsistent, necessitating further clinical trials to validate their application. This review highlights the role of MSCs in cartilage regeneration and how the application of biomaterials and stimulatory signals can enhance chondrogenesis. The current treatments for osteochondral lesions of the ankle using regenerative medicine strategies are reviewed to provide a clinical context. The challenges for cartilage regeneration, along with potential solutions and safety concerns are also discussed.

Dental stem cells: recent progresses in tissue engineering and regenerative medicine

Since the disclosure of adult mesenchymal stem cells (MSCs), there have been an intense investigation on the characteristics of these cells and their potentialities. Dental stem cells (DSCs) are MSC-like populations with self-renewal capacity and multidifferentiation potential. Currently, there are five main DSCs, dental pulp stem cells (DPSCs), stem cells from exfoliated deciduous teeth (SHED), stem cells from apical papilla (SCAP), periodontal ligament stem cells (PDLSCs) and dental follicle precursor cells (DFPCs). These cells are extremely accessible, prevail during all life and own an amazing multipotency. In the past decade, DPSCs and SHED have been thoroughly studied in regenerative medicine and tissue engineering as autologous stem cells therapies and have shown amazing therapeutic abilities in oro-facial, neurologic, corneal, cardiovascular, hepatic, diabetic, renal, muscular dystrophy and auto-immune conditions, in both animal and human models, and most recently some of them in human clinical trials. In this review, we focus the characteristics, the multiple roles of DSCs and its potential translation to clinical settings. These new insights of the apparently regenerative aptitude of these DSCs seems quite promising to investigate these cells abilities in a wide variety of pathologies. Key messages Dental stem cells (DSCs) have a remarkable self-renewal capacity and multidifferentiation potential; DSCs are extremely accessible and prevail during all life; DSCs, as stem cells therapies, have shown amazing therapeutic abilities in oro-facial, neurologic, corneal, cardiovascular, hepatic, diabetic, renal, muscular dystrophy and autoimmune conditions; DSCs are becoming extremely relevant in tissue engineering and regenerative medicine.

An overview of platelet products (PRP, PRGF, PRF, etc.) in the Iranian studies

Aim

The aim of the study was to carry out a review of published studies on various platelet products in Iranian studies.

Materials & methods

Electronic databases were searched for relevant articles. Two review authors independently extracted data via a tested extraction sheet, and disagreements were resolved by a meeting with a third review author.

Results

Bone disorders (25%), wound and fistula (16%), dental and gingival disorders (14%) and osteoarthritis (11%) have more relative frequency based on different fields.

Conclusion

The necessity of pursuing standard protocols in the preparation of platelet products, stating the precise content of platelets and growth factors, and long-term follow-up of study subjects were the most important points in Iranian studies.

Short review on human umbilical cord lining epithelial cells and their potential clinical applications

BACKGROUND

The human umbilical cord has been studied extensively in the past two decades. It is free of ethical dilemmas, non-tumorigenic, and less immunogenic and thus provides a significant advantage over other stem cell sources. The cord lining yields both mesenchymal and epithelial stem cells. The mesenchymal cells have been appraised at length by many researchers, which led to the current review focusing on the cord lining epithelial cells (CLECs). These cells have high proliferative capacity and their superior harvest and multiplication, using the revolutionary CellOptima^TM technology, makes them better candidates in comparison to contemporary adult stem cells. Following 30 replication cycles these cells have been observed to retain their stemness, with their phenotype and karyotype intact. However, their remarkable immunosuppressant properties, protecting self as well as co-transplanted allografts from rejection, are what truly define their transplantation potential. They have been successfully applied to many chronic conditions, using animal models, including type 1 diabetes, limbal stem cell deficiency, burn injuries, and wound healing, etc. with encouraging results.

CONCLUSIONS

This review first discusses some of the advantages afforded by CLECs over other stem cell lines and then delineates their potential use in various clinical applications. Clinical trials using CLECs are currently underway in the US in collaboration with CellResearch Corp. and their potential positive findings will help garner an FDA approval, likely leading to the eventual commercialization of this promising technology.