SCIENCE
IN SHOR
T
SCHOOL
Potential and actual use
of stem cells in regenerative
medicine
Anita Helińska, Barbara Świerczek, Igor Meszka, Bartosz Mierzejewski, Karolina Archacka
Summary:
In Recently, a great interest in stem cells issues has risen both among the scientific community and the society. Meeting these requirements, organizations promoting knowledge about stem cells have been founded. Among them EuroStemCell – a partnership of stem cell research centres and institutions from many European countries has been established. Additionally, different types of ac-tions devoted to stem cells issues have been initiated with UniStem Day being the great example of them. The UniStem Day is organized every year simultaneously at many European universities. The main aim of this event is to disseminate knowledge about stem cell research among high school students. However, many myths about stem cells still exist in public opinion. This article – being the follow-up of the publications focused on stem cells and published in Biological and Environmental Education in 2013 – presents the current information about stem cells with special emphasis on their potential and actual use in regenerative medicine.
Key words: stem cells, regenerative medicine, cell therapy,
clini-cal trials, dissemination of knowledge
Introduction
Regenerative medicine is an interdisciplinary branch of science that includes medical biology, bio-technology, and biophysics. Its main aim is to elabo-rate and apply methods that allow the improvement of structure and function of tissues and organs that dete-riorated due to disease, injury or as a result of ageing. To this end projects focused on tissue engineering, whose main aim is to obtain organs in laboratory that may be used in transplantation, as well as research concerning stem cells that play the key role in regeneration of dif-ferent tissues in physiological conditions are conducted (the characteristics of different types of stem cells was presented in the articles published in Biological and En-vironmental Education in 2013; Archacka 2013; Bauer et al., 2013; Świerczek et al., 2013). Despite the progress, until 2015 the only stem cell therapy that was clinically approved was the bone marrow transplant.
There are several types of stem cells in bone marrow, including hematopoietic stem cells (HSC), from which all types of blood cells are derived (Bianco et al., 2001). Therefore HSC are crucial for functionality of hemat-opoietic and immune systems. Failure in the process of blood cell formation – hematopoiesis – is the main reason for manyhematopoietic system disorders char-acterized by high mortality, such as acute and chronic myeloid leukemias (Linker, 2003) and cancer of the lymphatic system (Passweg et al., 2015). For example, leukemia develops as a result of uncontrolled prolif-eration of white blood cells (leukocytes) which prevail over healthy blood cells, leading to patient’s health de-terioration. As a result of the decreased number of red blood cells (erythrocytes) responsible for the oxygen distribution throughout the body, the patient becomes weaker. Moreover, he suffers from frequent bleedings and numerous bruises on the skin resulting from the shortage of blood platelets which are crucial for blood clotting. Colonization of lymph nodes, liver, and spleen by tumor cells leads to the gradual impairment of their functioning. In order to destroy tumor cells in patients suffering from the diseases mentioned above, chemo-therapy and/or radiochemo-therapy areapplied. However this procedure leads tothe destruction of other blood cells, including HSC (Fig. 1). The reduced immune resistance means that even mild infection or rhinitis may lead to life-threatening complications. Transplantation of HSC gives a chance to reconstitute the destroyed bone mar-row of the recipient and – in consequence – to reini-tiate the production of new blood cells including the immune cells that combat pathogens – leukocytes, monocytes, eosinophils, and basophils (Fig. 1). In addi-tion, the donor immune cells which are also present in the graft, recognize and destroy the cancer cells which can remain in the patient’s body despite the radio- or chemotherapy (Hilgendorf et al., 2015).
Igor Meszka: Students Scientific Association of Medical
Biology „Antidotum”, Faculty of Biology, University of War-saw; Department of Cytology, Faculty of Biology, University of Warsaw
received: 15.02.2016; accepted: 18.03.2016; published: 1.04.2016
Bartosz Mierzejewski: Students Scientific Association of
Medical Biology „Antidotum”, Faculty of Biology, University of Warsaw; Department of Cytology, Faculty of Biology, University of Warsaw
dr Karolina Archacka: Department of Cytology, Faculty of
Biology, University of Warsaw
mgr Barbara Świerczek: Department of Cytology, Faculty
of Biology, University of Warsaw
mgr Anita Helińska: Department of Cytology, Faculty of
Biology, University of Warsaw
SCIENCE
IN SHOR
T
SCHOOL
Transplantation of HSC obtained from a donor is an example of the allogeneic graft, in which the donor and the recipient of transplanted cells have similar hu-man leukocyte antigens (HLA). Perfectly matched HLA compatibility occurs between 20 to 25% of donors and
recipients, usually relatives. Therefore many alloge-neic transplantations are performed between siblings, children and parents, or other family members. In the case of autologous transplantation the same person is both the donor and the recipient. The first successful
allogeneic bone marrow transplantation in Poland was conducted by professors Cezary Szczylik and Wiesław Jędrzejczak in 1984 (Sobiak, 2011). Nowadays HSC transplantations are available in 17 clinical centers in Poland. In each of them the average number of trans-plantations ranges from 20 to 165 per year (Resolution of the Council of Ministers No. 164/2010, the National Programme for the Development of Transplantation Medicine). Since 1984 in Poland circa 9 000 HSC trans-plantations have been performed. As a result of them five thousand patients are still alive (Resolution of the Council of Ministers No. 164/2010, the National Pro-gramme for the Development of Transplantation Medi-cine). The average number of bone marrow transplan-tations conducted per every 10 million of citizens in European Union is 450 per year while in Poland – 210 per year (Resolution of the Council of Ministers No. 164/2010, the National Programme for the Develop-ment of Transplantation Medicine). In 2013 the total number of HSC transplantations conducted in Europe reached almost 40 000, with 43% of them in allogeneic while 57% – in autologous conditions (Passweg et al., 2015). There are several factors that are crucial for mak-ing a decision about transplantation performance in-cluding the type of disease, the age and condition of the patient as well as the donor availability. Reconstruction of the hematopoietic and immune system usually takes from two to six weeks. During this time the patient stays in special conditions which minimize the risk of infection. The transfusion of an additional blood por-tion is often necessary to supplement the number of red blood cells or platelets in the patient. Another compli-cation which may occur after the bone marrow trans-plantation is graft versus host disease (GVHD). GVHD develops when thetransplanted donor cells recognize the recipient’s blood cells as strange ones and destroy them (Ball and Egeler, 2008). GVHD is mostly
mani-Fig. 1. The outline of bone marrow transplantation in allogeneic conditions
The production of blood cells in bone marrow of patient suffering from leukemia is impared (green frame). Radiotherapy leads to the destruc-tion of tumor cells which cause leukemia development but also other cells that are present in the bone marrow. This results in destrucdestruc-tion of the patient’s hematopoietic system (yellow frame). Bone marrow of the donor contains healthy hematopoietic stem cells. They can be isolated from the femur (blue frame) through the puncture. Transplantation of bone marrow stem cells obtained from a donor (black frame) leads to the reconstruction of the damaged hematopoietic system of the recipient and – in consequence – in the resumption of blood cell production (red frame).
SCIENCE
IN SHOR
T
SCHOOL
fested by skin rash, mouth ulcers, erosions in the geni-tals, and dry eye syndrome. However, the more serious complications may also occur including necrotic lesions in the liver, intestines, and other organs, which can even lead to death of the patient (Chinen and Buckley, 2010).
Although bone marrow transplantation has become a routine medical procedure, it is truly beneficial only in the case of hematologic diseases. Despite numerous
HOLOCLAR – a new chapter in the cornea damage
treatment
Cornea is a transparent layer covering the front of the eyeball (Fig. 2A). Apart from its protective role the cornea serves also as an element of the eye optical sys-tem. Due to cornea transparency the light can reach the retina which coats the inner part of the eyeball (Fig. 2A). Cornea contains a small pool of stem cells known as limbal stem cells which are responsible for the regen-eration of the cornea after its damage (discussed in Pel-legrini and De Luca, 2014). Unfortunately, the cornea regeneration becomes impossible if the injury also af-fects the stem cells population. Expansion of blood ves-sels and connective tissue on the surface of the eyeball leads to the formation of light-impermeable membrane which restricts the vision ability of the patient (Pel-legrini and De Luca, 2014). For many years the trans-plantation of cornea obtained from deceased donors was the only available treatment for the patients suffer-ing from diseases caused by limbal stem cells deficiency (LSCD). In 1905 the first documented transplantation of cornea isolated from a deceased donor to a patient with chemical eye burn was conducted by a medical doctor, Eduardo Zirma. Interestingly, as a result of theimmune privilege of the eye nearly 90% of corneal transplantations were successful. The phenomenon of immune privilege means that the transplant is accepted despite thedifferences between HLA of the donor and recipient. Additionally, in order to minimize the risk of immune reaction the corticosteroids with anti-inflam-matory and anti-allergic properties were administrated to the eye after the transplantation (Szaflik and Izdeb-ska, 2003). However, the major limitation of the cornea transplantations was the reduced availability of the tissue samples. Moreover, some patients suffered from strong inflammation and ulceration of the eye. As an scientific publications describing the phenomenon of
stem cell plasticity, i.e. conversion of stem cells of one tissue into cells specific for other tissues (discussed in Bauer et al., 2013), the results of current research indi-cate that HSC efficiently form only blood cells and does not transform into other types of cells, for example neu-rons or myoblasts (Flores-Guzman et al., 2013). Thus, other sources of stem cells with potential therapeutic effect are still being sought.
Fig. 2. Potential stem cell based therapies for eye diseases
Anatomy of the eye. Red color indicates corneal limbus, where limbal stem cells reside.
The outline of LSCD therapy based on the limbal stem cells. Limbal stem cells are isolated from corneal limbus of the patient’s healthy eye and subsequently cultured in vitro. Cells are placed on the fibrin lens when sufficient number of them is available. From 80 to 300 thousands of cells are placed on a lens with 2 cm in diameter. The implant is transferred to the patient’s injured eye, what lead to the cornea reconstruction. The derivation and transplantation of retinal pigmented epithelium cells differentiated from pluripotent stem cells. Transplantation of retinal pigmented epithelium cells is considered as a potential therapy for patients suffering from AMD and Stargardt’s disease. Such cells can be obtained from pluripotent ESC. Transplantation of 50-150 thousands of these cells to the patients suffering from Stargardt’s disease or AMD leads to the restoration of retinal pigmented epithelium layer in the macula and – in consequence – to the vision improvement.
SCIENCE
IN SHOR
T
SCHOOL
therapy was initially approved for use for patients with LSCD (the report of the European Medicines Agency, EMA/25273/2015). In 2010 the results of Holoclar ther-apy were described in detail. The transplantation of the implant resulted in a significant reconstruction of the cornea and the improvement in vision ability in 75 out of 104 patients (Rama et al., 2010). On 17th February
2015 the Holoclar therapy was finally approved by the European Commission for use in medical centers in all member countries of the European Union.
The clinical trials based on pluripotent stem cells
for eye diseases treatment
Age-related macular degeneration (AMD) is another disease affecting the eye. AMD develops in older people and is the cause of 5% of all registered cases of blindness (Pascolini and Mariotti, 2012). Macula is a part of reti-na, which is characterized by the highest number of the eye photoreceptors (cones and rods). Cones and rods are responsible for the conversion of light into chemical signals that are transduced to the brain (Fig. 2C). The degeneration of macula leads to the vision impairment and – finally – to the vision loss. Similar symptoms oc-cur in the case of Stargardt’s disease. This genetic disor-der develops in children and is caused by the mutation in ABCA4 gene encoding the protein responsible for metabolites transport in the retina. ABCA4 gene mu-tation leads to the accumulation of toxic substances in the retinal pigmented epithelium cells leading to their death. Since these cells support rods and cones func-tions by providing them with nutrients, their loss leads to the death of photoreceptors (Glazer and Dryja, 2002). Stargardt’s disease is diagnosed in one in ten thou-sand children (Sharokh Kapadia, 2000) and, similarly to AMD, remains incurable. In 2015 the results of the first clinical trial based on the use of stem cells in AMD
and Stargardt’s disease treatment were published. Pluri-potent stem cells were differentiated into retinal pig-mented epithelium cells (Schwartz et al., 2015; Fig. 2C). Previous studies on mice proved that transplantation of retinal pigmented epithelium cells into the eye with de-generating macula prevents death of photoreceptors (Lu et al., 2009). Unfortunately, transplantation of retinal pigmented epithelium cells in autologous conditions re-quired highly dangerous and invasive isolation of cells from patient’s retina (Binder et al., 2012). Clinical trials conducted by Schwartz and his colleagues encompassed 18 patients: nine with Stargardt’s disease and nine with AMD. Transplantation of cells obtained through the differentiation of pluripotent stem cells resulted in the restoration of retinal pigmented epithelium in 13 pa-tients (Fig. 2C). After six and 12 months the visual acu-ity improvement was confirmed in three patients while other four did not show disease progression (Schwartz et al., 2015). The first clinical trials based on pluripotent stem cells were proposed for eye diseases for a reason. As mentioned above, the eye is an immune-privileged site (Medawar, 1948). Therefore, even in the case of non-matched HLA between donor and recipient, transplan-tation of cells into the eye does not trigger the immu-nological response that would lead to the destruction of cells recognized as “strange” (Streilein, 1987). This phe-nomenon results from the anatomical separation of the eye from lymphatic vessels. This precludes immune cells which are responsible for therecognition and removal of strange cells from migrating to the eye (Streilein, 2003). Additionally, some structures of the eye, such as retina may block the activity of immune cells and re-ducethe immunological response.
Due to their ability to differentiate into all cell types building mammalian body, pluripotent stem cells are considered as a potential source of cells for therapies for other diseases (reviewed in Świerczek et al., 2013; alternative, microsurgical procedures involving the
re-moval of the damaged cornea (known as keratectomy) were performed. However, this method had mostly an aesthetical effect and did not lead to the recovery of vi-sion. The first transplantations of stem cells to injured cornea were performed in the 70s of the XX century, but at that time they did not result in the expected thera-peutic effect. The development of effective therapy for damaged cornea required many years of collaboration between researchers, medical doctors, and patients par-ticipating in clinical trials focused on this new treat-ment, further supported by huge money donations. This resulted in Holoclar – the first stem cell therapy for pa-tients with LSCD – which was eventually approved in 2015 (Fig. 2B).
Holoclar is dedicated for patients with LSCD in one eye. The second healthy eye serves as a source of cells which are required for transplantation. First, doctors isolate 1-2 mm2 fragment of the limbus from the healthy
eye of the patient (Fig. 2B). Next, cells obtained from the limbus biopsy are multiplied in the special culture dishes (Fig. 2B). When appropriate number of cells is available, cells are placed on a special eye lens which is then transplanted to the injured eye of the patient. Ear-lier, the connective tissue membrane covering the front of the eyeball is removed by microsurgical techniques. The procedure described above serves as an example of autologous transplantation which is characterised by the lack of the risk of the graft rejection. Holoclar therapy is especially valuable because it leads both to the restoration of the damaged cornea with transplant-ed cells as well as to the renewal of limbal stem cell population. This means that cornea regains the ability to regenerate in case of contingent damage. The most common side effect of Holoclar is the inflammation of the eyelid, while the most serious side effects are cornea perforation and ulcerative keratitis. In 2008 Holoclar
SCIENCE
IN SHOR
T
SCHOOL
Fig. 3). There are many diseases caused by the lack or improper functioning of certain cell types. Diabetes type I is an example of such diseases as it results from the insufficient number of pancreatic beta cells that pro-duce insulin. Insulin is a hormone which is responsi-ble for maintaining the normal level of glucose in the blood. Long-lasting high concentration of glucose in the blood, which results from untreated diabetes, may lead to vision impairment, healing deficiency, coma or even death. Every year approximately 80 thousands cases are diagnosed around the world (Chiang et al., 2014). Cur-rently available treatment involves insulin injections and maintaining proper diet which reduces disease pro-gression. For many years researchers have been trying to design a protocol for the conversion of pluripotent stem cells into insulin producing cells. In 2006 the method of efficient derivation of beta cells from embryonic stem cells (ESC) was described (D’Amour et al., 2006). Re-cently, the first clinical trials based on such cells has been started by ViaCyte company. Pancreatic beta cells, obtained through differentiation of ESC, are placed in a semi-permeable capsule, which is subsequently inject-ed under the skin of patients. Due to the capsule prop-erties the cells receive nutrients and oxygen from the bloodstream. Moreover, in response to thehigh glucose levels they can secrete insulin (described on ViaCyte. com). It is also important that the capsule protects the cells located within from the attack of host’s immune cells. ESC, as well as more specialized cells derived from them, are recognized as strange to the host and for this reason could be eliminated from the host body by the immune cells. The origin of ESC is another difficulty in the clinical application of these cells. ESC are derived from the embryos at early stages of development. Isola-tion of ESC may lead to the destrucIsola-tion of theembryo which remains controversial (Fig. 3). The promising alternatives for ESC are induced pluripotent stem cells
Fig. 3. Properties of pluripotent stem cells that promotes or inhibits their potential use in regenerative medicine
The diagram provides information about the characteristics of pluripotent stem cells that are favorable (green frame) or unfa-vorable (red frame) in the context of their potential clinical use.
Fig. 4. Properties of mesenchymal stem cells that promotes or inhibits their potential use in regenerative medicine
The diagram provides information about the characteristics of mesenchymal stem cells that are favorable (green frame) or un-favorable (red frame) in the context of their potential clinical use.
SCIENCE
IN SHOR
T
SCHOOL
of a mouse. He observed a formation of bone, cartilage, and adipose tissues in the areas engrafted by transplant-ed cells (Fritransplant-edenstein, 1980). Currently, it is known that these tissues were derived from multipotent MSC, which together with HSC are localized in bone marrow (Pojda et al., 2013). MSC are crucial elements of the niche for HSC that differentiate into all types of blood cells. MSC also participate in bones and cartilage remodelling, and can differentiate into adipocytes as well. Apart from bone marrow MSC are also present in liver, pancreas, kidney, muscles, and adipose tissue (Nombela-Arrieta et al., 2011). Over the years several methods for isolation of MSC from different organs and tissues as well as for their further culture in vitro were developed (Bianco, 2014). The morphology of MSC is similar to fibroblasts: they are fusiform, long, and adhere to the culture dish. Lately, more and more attention is being paid to adipose derived stem cells (ADSC), i.e. MSC derived from adi-pose tissue. It is associated with the fact that 200 thou-sand times more MSC can be obtained from adipose tissue than from bone marrow, where MSC make up no more than 0,002 % of all cells (Pojda et al., 2013).
The possibility of derivation of MSC from different niches (tissues and organs) in adult organisms as well as from the fetal tissues and organs such as placenta, Wharthon’s jelly or umbilical cord blood enhances the potential use of these cells in regenerative medicine (Fig. 4). In comparison to pluripotent stem cells MSC have more limited potential to differentiate (multipo-tency) and – in consequence – do not create teratomas after transplantation (Fig. 4). In the case of pluripotent stem cells even one inadequately differentiated cell in the graft may lead to teratoma formation (Fig. 3). Although teratomas are not malignant tumors they can develop in tissues and organs that are crucial for proper body func-tioning (for example lungs) leading to their destruction. On the other side, multipotency of MSC means that the
possible therapies based on these cells are not as numer-ous as in the case of pluripotent stem cells (Fig. 3, Fig. 4). However, MSC are characterized by unique feature – the ability for immunomodulation – which means that they can influencetheimmune system functioning. It has been proved that MSC secretesubstances that sup-press the activity of immune cells such as lymphocytes T and B, macrophages, and dendritic cells (Najar et al., 2016). These substances are called anti-inflammatory cytokines. Due to their unique features MSC are cur-rently tested as a possible tool in the therapy for differ-ent diseases. Growing popularity of MSC is indicated by the number of clinical trials based on these cells: in 2009 there were 30 of such clinical trials registered around the world, in 2013 – 300, while in February 2016 – fivethousand. Most of these trials are focused on the potential application of MSC in the therapy for skeletal diseases such as children osteogenesis imperfecta which develops due to themutation in collagen coding gene. Collagen is the main component of laminae osseae. The presence of abnormal form of the collagen is manifested by an excessive fragility of bones which can be broken even during sleep (Biggin and Munns, 2014). The other group of trials are focused on testing the immunomod-ulatory ability of MSC. For example, MSC are currently being tested in the treatment for Crohn’s disease, which is characterized by a chronic inflammation of gastro-intestinal tract. The results of both clinical trials men-tioned above have not been released yet. However, in 2014 the results of other clinical trial were published, indicating that transplantation of MSC to patients suf-fering from rheumatoid arthritis led to the reduction of pain caused by the strong inflammation in the joints (El-Jawhari et al., 2014). This effect was achieved due to anti-inflammatory cytokines produced by MSC which suppressed the activity of lymphocytes B and T, and – in consequence – limited the inflammation (El-Jawhari et (iPSC), which similarly to ESC are able to differentiate
into all cells types and tissues in the mammalian body (described in Świerczek et al., 2013).
First iPSC were derived by Takahashi and Yamana-ka in 2006 (TaYamana-kahashi and YamanaYamana-ka, 2006). Nowadays such cells can be obtained from nearly all fetal or adult cells through the procedure called reprogramming (re-viewed in Świerczek et al., 2013). Thanks to iPSC tech-nology cells that could serve as an universal source of various cells types for autologous transplantation became available. In July 2013 Japanese government allowed the first clinical trial based on iPSC in AMD treatment. iPSC were derived from fibroblasts which were isolated from the patients participating in the study. Next, iPSC were differentiated into retinal pig-mented epithelium cells which were transplanted into the patients’ eyes (Kamao et al., 2014). The results of this clinical trial have not been published yet. However, in 2015 the trial was stopped. It is known that a mutation which could potentially cause tumor formation was found in iPSC derived from one of the patients. This in-dicates that there are still many challenges to overcome before iPSC are successfully and safely used in regenera-tive medicine (Fig. 3).
Mesenchymal stem cells and their potential use
in regenerative medicine
Pluripotent stem cells are not the only cells that could potentially be used in regenerative medicine. Re-cently more and more projects are focused on mesen-chymal stem cells (MSC). MSC were discovered in the 60s of the last century but their actual physiological role remained unknown for a long time. In 1980 a Russian scientist – Alexander Friedenstein – published the re-sults of his experiments in which he transplanted cells isolated from bone marrow to other organs and tissues
SCIENCE
IN SHOR
T
SCHOOL
al., 2014). It should be noted, however, that the trans-plantation of MSC influenced only the symptoms of this disease, not its cause. Despite some difficulties in the clinical application of MSC, the first MSC-based drug – Prochymal – was approved in Canada, New Zea-land, and USA in 2012. Prochymal is produced by Osi-ris Therapeutics Company and contains MSC derived from donors aged from 18 to 30 years old. The drug is currently used to prevent the development of GVHD, described earlier in the article. Its main effect relies on the secretion of both anti-inflammatory cytokines, and growth factors that suppress inflammatory cells and in-duce tissue regeneration, respectively (Kurtzberg et al., 2014)
Knowledge dissemination as a response of the
scientific community to the myths about stem
cells
Despite the fact that any therapy based on MSC has not yet been approved for humans (except the Prochy-mal drug), the company offering the transplantation of MSC as a treatment for many diseases hasexisted in Ita-ly for the past few years. It was founded by Davide Van-noni, a psychologist who was spreading the information about the possibility of curing such serious diseases as spinal muscular atrophy, cerebral palsy, amyotrophic lateral sclerosis, and Huntington’s disease. All of them develop due to the dysfunctions of nervous system and still remain incurable. The method proposed by Van-noni was based on the transplantation of neurons which were previously obtained in the laboratory from MSC, into the patients’ circulatory system. In physiological conditions, neurons are responsible for signal transmis-sion through the body, serving as a functional basis of the nervous system. Although the therapeutic effect of MSC transplantations in the case of nervous system
dis-eases had hasnot been verified in any scientific studies, the idea of using MSC in therapies has become popular in Italy and also in other countries. Since 2007 many MSC transplantations have been performed, but not documented in the proper way. This made the assess-ment of the actual number of people participating in this procedure impossible (Abbot, 2013). In 2013 in Rome, demonstrators claimed public access to stem cell trans-plantations, even if not properly verified. Accordingto the demonstrators’ beliefs, such approach would be ben-eficial for patients suffering from chronic, life-threating diseases, which could not be efficiently cured by avail-able methods. In response to this social phenomena, leading scientists and physicians described in details
possible side effects and danger resulting from the use of unproved treatments (Bianco et al., 2013). The gaps and shortcomings accompanying the transplantation of MSC were also indicated. Nowadays, the implementa-tion of new treatment for human requires complex clin-ical trials (Fig. 5; Maciulaitis et al., 2013). Among the controversial issues of MSC transplantation there were insufficient characterization of injected cells as well as the lack of proper information on the method used for conversion of MSC into neurons. The results released by the company have not been confirmed by scientists (Carozzi et al., 2012). Moreover, it remains unclear how the cells were injected into the body of the patients. In-troduction of such cells into circulatory system, which
Fig. 5. Stages of bringing onto market new medical product
The diagram shows the stages of implementation of a new medical product in accordance with the legal requirements in Europe. The process is preceded by a complex laboratory research (preclinical stage) in vitro (experiments using cell culture) and in vivo (experiments using animal models). The following clinical trials are divided into four phases. Their common goal is to verify the efficiency, safety and identification of possible side effects of tested medical product. Starting of the next phase of clinical trials is not possible without the completion of the previous stage.
SCIENCE
IN SHOR
T
SCHOOL
is not their physiological niche, generates possible side effects such as uncontrolled migration of transplanted cells to different tissues and organs (including thebrain and kidneys) which can be deleterious for their further functioning. The investigation conducted by the Ital-ian Pharmaceutical Agency (AIFA, it. Agenzia ItalItal-iana del Farmaco) revealed that the safety requirements for transplantation in humans were not fulfilled during the procedure described above (Abbot, 2013). The response of scientific community to social needs encompasses publishing of articles but also setting up organisations focused on disseminating the knowledge about the pro-gress in biomedical sciences. Numerous articles, mov-ies, and workshops have been created by scientists who decided to share their knowledge. An example of such initiative is UniStem Day – the a meeting dedicated for teachers and high school students, which is organised annually on dozens of European universities. This event was initiated by a group of scientists at the University of Milan. In 2016 UniStem Day will take place for the first time in Poland, at the University of Warsaw. This day lectures, workshops, movie shows, and debates will give the teachers and students a great opportunity to learn about stem cells, and their potential and actual clinical application.
Despite intensive research and numerous clinical trials bone marrow transplant, Holoclar therapy, and Prochymal are the only examples of the stem cells based treatments that have been approved for use in humans. Great attention is paid to the potential use of stem cells for improving functioning of such crucial organs as the heart and brain. Although currently any cell therapy for these organs are available, cooperation between scien-tists and doctors may lead to the development of new treatment based on the latest achievements in biomedi-cal science as it has happened in the case of Holoclar therapy.
References
Abbot A (2013). Stem-Cell ruling riles reasearchers. Nature. 495(7442):418–419.
Ball LM, Egeler RM (2008). Acute GvHD: pathogenesis and classifi-cation. Bone Marrow Transplant. Suppl 2:S58-64.
Bauer D, Neska J, Archacka K (2013). Stem cells. Part III – adult stem cells. Biological and Environmental Education. 4(48):3-10. Bianco P, Riminucci M, Gronthos S, Robey PG (2001). Bone marrow
stromal stem cells: nature, biology, and potential applications.
Stem Cells. 19(3):180-192.
Bianco P, Barker R, Brüstle O, Cattanego E, Clevers H, Daley QG, De Luca M, Goldstain L, Lindvall O, Mummery C, Robey GP, Sattler C, Smith A (2013). Regulation of stem cell therapies under attack in Europe: for whom the bell tolls. EMBO J. 32(11):1489–1495. Bianco P (2014). „Mesenchymal” stem cells. Annu Rev Cell Dev Biol.
30:677-704.
Biggin A, Munns CF (2014). Osteogenesis imperfecta: diagnosis and treatment. Curr Osteroporos Rep. 12(3), 279-288.
Binder S, Stolba U, Krebs I, Kellner L, Jahn C, Feichtinger H, Povelka M, Frohner U, Kruger A, Hilgers RD, Krugluger W (2012). Trans-plantation of autologous retinal pigment epithelium in eyes with foveal neovascularization resulting from age-related macular de-generation: a pilot study. Am J Ophthalmol. 133(2):215-225. Breitbach M, Bostani T, Roell W, Xia Y, Dewald O, Nygren JM,
Fries JWU, Tiemann K, Bohlen H (2007). Potential risks of bone marrow cell transplantatations into infarcted hearts. Blood. 110(4):1362-1369.
Carrozzi M, Biondi A, Zanus C, Monti F, Alessandro V (2012). Stem cells in severe infantile spinal muscular atrophy (SMA1).
Neuro-muscul Disord. 22(11):1032–1034.
Chiang JL, Kirkman MS, Laffel LM, Peters AL, Type 1 Diabetes So-urcebook Authors (2014). Type 1 diabetes through the life span: a position statement of the American Diabetes Association.
Dia-betes Care. 37(7):2034-2054.
Chinen J, Buckley RH (2010). Transplantation immunology: solid organ and bone marrow. J Allergy Clin Immunol. 125(2 Suppl 2):S324-335.
D’Amour KA, Bang AG, Eliazer S, Kelly OG, Agulnick AD, Smart NG, Moorman MA, Kroon E, Carpenter MK, Baetge EE (2006). Production of pancreatic hormone-expressing endocrine cells from human embryonic stem cells. Nat Biotechnol. 24(11):1392-1401.
El-Jawhari JJ, El-Sherbiny YM, Jones EA, McGonagle D (2014). Me-senchymal stem cells, autoimmunity and rheumatoid arthritis.
QJM. 107:505-514.
Flores-Guzmán P, Fernández-Sánchez V, Mayani H (2013). Concise review: ex vivo expansion of cord blood-derived hematopoietic
stem and progenitor cells: basic principles, experimental approa-ches, and impact in regenerative medicine. Stem Cells Transl Med. 2(11):830-838.
Friedenstein AJ (1980). Stromal mechanisms of bone marrow: clo-ning in vitro and retransplantation in vivo. Haematol Blood
Transfus. 25:19-29.
Glazer LC, Dryja TP (2002). Understanding the etiology of Stargardt’s disease. Ophthalmol Clin North Am. 15(1):93-100.
Haagdorens M, Van Acker SI, Van Gerwen V, Ní Dhubhghaill S, Koppen C, Tassignon MJ, Zakaria N (2016). Limbal Stem Cell Deficiency: Current Treatment Options and Emerging Therapies.
Stem Cells Int. 9798374.
Kamao H, Mandai M, Okamoto S, Sakai N, Suga A, Sugita S, Kiryu J, Takahashi M (2014). Characterization of human induced plu-ripotent stem cell-derived retinal pigment epithelium cell sheets aiming for clinical application. Stem Cell Reports. 2(2):205-218. Kapadia OD (2000). Stargardt’s macular dystrophy. Clinical Eye and
Vision Care. Clin Eye Vis Care. 12(1-2):71-78.
Kurtzberg J, Prockop S, Teira P, Bittencourt H, Lewis V, Chan K ,Horn B ,Yu L , Talano J, Nemecek E, Mills Ch, Chaudhury S (2014). Allogeneic Human Mesenchymal Stem Cell Therapy (Re-mestemcel-L, Prochymal) as a Rescue Agent for Severe Refractory Acute Graft-versus-Host Disease in Pediatric Patients. Biol Blood
Marrow Transplant. 20(2):229-235.
Linker CA (2003). Autologous stem cell transplantation for acute myeloid leukemia. Bone Marrow Transplant. 31:731–738. Lu B, Malcuit C, Wang S, Girman S, Francis P, Lemieux L, Lanza R,
Lund R (2009). Long-term safety and function of RPE from hu-man embryonic stem cells in preclinical models of macular dege-neration. Stem Cells. 27(9):2126-2135.
Maciulaitis R, D’Apote L, Buchanan A, Pioppo L, Schneider CK (2012). Clinical development of advanced therapy medicinal pro-ducts in Europe: evidence that regulators must be proactive.
Mo-lecular Therapy. 20(3), 479-482.
Medawar PB (1948). Immunity to homologous grafted skin; the fate of skin homografts transplanted to the brain, to subcutaneous tissue, and to the anterior chamber of the eye. Br J Exp Pathol. 29(1):58-69.
Najar M, Raicevic G, Fayyd-Kazan H, Bron D, Toungouz M, Lag-neaux L (2016). Mesenchymal stromal cells and immunomo-dulation: A gathering of regulatory immune cells. Cytotherapy. 18(2):160-171.
Nombela-Arrieta C, Ritz J, Silberstein LE (2011). The elusive nature and function of mesenchymal stem cells. Nat Rev Mol Cell Biol. 12(2):126-131.
Pascolini D, Mariotti SP (2012). Global estimates of visual impair-ment: 2010. Br J Ophthalmol. 96(5):614-618.
SCIENCE
IN SHOR
T
SCHOOL
Duarte RF, Dufour C, Falkenburg JH, Farge-Bancel D, Gennery A, Kröger N, Lanza F, Nagler A, Sureda A, Mohty M, European Society for Blood and Marrow Transplantation (EBMT) (2015). Hematopoietic SCT in Europe 2013: recent trends in the use of alternative donors showing more haploidentical donors but fewer cord blood transplants. Bone Marrow Transplant. 50(4):476-482. Pellegrini G, De Luca M (2014). Eyes on the prize: limbal stem cells
and corneal restoration. Cell Stem Cell. 15(2):121-122.
Pojda Z, Macha E, Kurzyk A, Mazur S, Dębski T, Gilewicz J, Wysocki J (2013). Mesenchymal Stem Cells. Advanced in Biochemistry. 59(2):187-197.
Rama P, Matuska S, Paganoni G, Spinelli A, De Luca M, Pellegrini G (2010). Limbal stem-cell therapy and long-term corneal regenera-tion. N Engl J Med. 363(2):147-155.
Schwartz SD, Regillo CD, Lam BL, Eliott D, Rosenfeld PJ, Gregori NZ, Hubschman JP, Davis JL, Heilwell G, Spirn M, Maguire J, Gay R, Bateman J, Ostrick RM, Morris D, Vincent M, Anglade E, Del Priore LV, Lanza R (2015). Human embryonic stem cell-derived retinal pigment epithelium in patients with age-related macular degeneration and Stargardt’s macular dystrophy: follow-up of two open-label phase 1/2 studies. Lancet. 385(9967):509-516. Sobiak J (2011). Organ and hematopoietic stem cell transplantations
– historical background. JMS. 80(2):157–161.
Streilein JW (1987). Immune regulation and the eye: a dangerous compromise. FASEB J. 1(3):199-208.
Streilein JW (2003). Ocular immune privilege: the eye takes a dim but practical view of immunity and inflammation. J Leukoc Biol. 74(2):179-85.
Szaflik J, Izdebska J (2003). Corneal transplantation. Guide for GPs. 6(6):69-72.
Świerczek B, Dudka D, Archacka K (2013). Stem cells. Part II – plu-ripotent stem cells. Biological and Environmental Education.
2:2-13.
Takahashi K, Yamanaka S (2006). Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors. Cell. 126(4):663-676.
Yoshida M, Takeuchi M, Streilein JW (2000). Participation of pig-ment epithelium of iris and ciliary body in ocular immune privi-lege. 1. Inhibition of T-cell activation in vitro by direct cell-to-cell contact. Invest Ophthalmol Vis Sci. 41(3):811-821.
Websites
Abbot A (2013). Italian stem-cell trial based on flawed data. Nature. The article available on:
http://www.nature.com/news/italian-stem-cell-trial-based-on--flawed-data-1.13329.
The characteristics of the VC-01 therapy by ViaCyte company. The product description available on:
http://viacyte.com/products/vc-01-diabetes-therapy/
Mesenchymal stem cell therapy for the treatment of severe or refrac-tory inflammarefrac-tory and/or autoimmune disorders. The informa-tion on clinical trial available on:
https://clinicaltrials.gov/ct2/show/NCT01540292
Repeated infusions of mesenchymal stromal cell in children with os-teogenesis imperfecta (STOD3). The information on clinical trial available on:
https://clinicaltrials.gov/ct2/show/NCT01061099?term=Osteoge nesis+Imperfecta+mesenchymal&rank=1
Report of the European Medicines Agency, EMA/25273/2015 (2014). Assessment report. Holoclar. International non-proprietary name: Ex vivo expanded autologous human corneal epithelial cells containing stem cells. European Medicines Agency. Infor-mation on clinical trial available on:
www.ema.europa.eu/docs/en_GB/document_library/EPAR_ Public_assessment_report/human/002450/WC500183405.pdf
Resolution of the Council of Ministers No. 164/2010, “The National Programme for the Development of Transplantation Medicine” (consolidated text). The resolution available on:
http://www2.mz.gov.pl/wwwfiles/ma_struktura/docs/program_ wieloletni_04032011.pdf
Acknowledgments
The article was published during implementation of a grant financed from the funds of the National Science Centre (decision number DEC-2012/05/D/ NZ3/02081; head of the project – Karolina Archacka) and a project suppor-ted by the National Centre of Research and Development (grant number PBS3/A7/22/2015) as well as DSM project – intramural grant for young scientists at Faculty of Biology, University of Warsaw – for Anita Helińska (project number W501/86/110114).
Special thanks to Mr. Jarosław Rak for the correction of the English version of the article.
