E. Michalopoulos - Academia.edu (original) (raw)
Papers by E. Michalopoulos
Human Reproduction
Study question This study aimed to the evaluation of PRP injection in women with ovarian dysfunct... more Study question This study aimed to the evaluation of PRP injection in women with ovarian dysfunction (with POR, POI, perimenopause and menopause) to promote the ovarian rejuvenation. Summary answer Intraovarian infusion of autologous PRP exhibited remarkable evidence and promising results to restore ovarian insufficiency. What is known already Ovarian dysfunctions, such as premature ovarian insufficiency (POI) and poor ovarian response (POR) are conditions, characterized by the collapse of ovarian function and are considered currently as a global public health issue. Primary factors that are associated with female infertility include endocrine dysfunction, failure of embryo implantation, endometriosis, and other related pathologies such as polycystic ovary syndrome (PCOS), various environmental factors and inflammatory disease. For this purpose, the rejuvenation of the ovaries using the intraovarian PRP injections may result in increased release of follicles from the available reser...
Transplantation Proceedings, 2015
ABSTRACT The loss or damage of an organ or tissue is one of the most common and devastating probl... more ABSTRACT The loss or damage of an organ or tissue is one of the most common and devastating problems in healthcare today. Tissue engineering applies the principles of engineering and biology toward the development of functional biological replacements that are able to maintain, improve, or restore the function of pathological tissues. The aim of the overall project is to study an already existing method for the decellularization of homograft vascular grafts for use in vascular surgery. The biomechanical integrity of native and decellularized rat aortas was assessed under uniaxial tension tests. For this purpose, 36 male rats (12 Wistar and 24 Dark Agouti [DA]) were used to excise their abdominal aortas. Twelve of the aortas were tested fresh (Wistar and DA rats), within 24 hours from euthanasia, and the rest were decellularized using a modified protocol (DA rats only). Fresh and decellularized samples (n = 12) were subjected to uniaxial tensile loading to failure, and the recorded stress-strain behaviour of each specimen was assessed in terms of 6 biomechanical parameters. No statistically significant differences were found in any of the biomechanical parameters studied between the decellularized DA rat aorta group and both the native DA and Wistar rat aorta groups (P > .05). Also, no significant difference was shown between the native DA and native Wistar rat aorta groups. The results from this study have shown that the decellularization protocol did not affect the mechanical properties of the native rat aorta. In addition to this, both native Wistar and native/decellularized DA rat aorta groups shared similar mechanical properties. Copyright © 2015 Elsevier Inc. All rights reserved.
Cord Blood Stem Cells and Regenerative Medicine, 2015
Abstract With the emergence of cord blood banking, arose concerns about whether cord blood units ... more Abstract With the emergence of cord blood banking, arose concerns about whether cord blood units stored in the banks were safe and effective as therapeutic products. These concerns led to the development of cord blood banking standards and establishment of quality programs in cord blood banks (CBBs). The notion of “quality” in CBBs is essential to ensure that all processes and systems in CBBs produce clinical quality cord blood units that are safe and effective for transplantation. These processes cover all aspects of collection, processing, cryopreservation, storage, disposal, selection, release and shipping of the cord blood units. The development/implementation of a quality management program and the final accreditation of cord blood banks/transplant programs can set the framework for the establishment of effective promotional strategies, which will control and certify all the possible factors which lead to a successful cord blood transplantation.
Transfusion, 2013
BACKGROUND: Cord blood (CB) units are stored from weeks to years in liquid-or vapor-phase nitroge... more BACKGROUND: Cord blood (CB) units are stored from weeks to years in liquid-or vapor-phase nitrogen until they are used for transplantation. We examined the effects of cryostorage in a mechanical freezer at-150°C on critical quality control variables of CB collections to investigate the possible use of mechanical freezers at-150°C as an alternative to storage in liquid-(or vapor-) phase nitrogen. STUDY DESIGN AND METHODS: A total of 105 CB units were thawed and washed at different time intervals (6, 12, 24, and 36 months). For every thawed CB unit, samples were removed and cell enumeration (total nucleated cells [TNCs], mononuclear cells [MNCs], CD34+, CD133+) was performed. In addition, viability was obtained with the use of flow cytometry, and recoveries were calculated. Also, total absolute colonyforming unit counts were performed and progenitor cell recoveries were studied by clonogenic assays. RESULTS: Significant differences (p < 0.05) were observed in certain variables (TNCs, MNC numbers, viability) when they were examined in relation with time intervals, while others (CD34+, CD133+) were relatively insensitive (p = NS) to the duration of time interval the CB units were kept in cryostorage condition. CONCLUSIONS: The data presented suggest that cryopreservation of CB units in a mechanical freezer at-150°C may represent an alternative cryostorage condition for CB cryopreservation. ABBREVIATIONS: BM = bone marrow; CB = cord blood; HSC(s) = hematopoietic stem cell(s); TNC(s) = total nucleated cell(s); UCB = umbilical cord blood.
Human Immunology, 2012
Aim Umbilical Cord Blood is validated as an alternative stem cell source allowing less HLA restri... more Aim Umbilical Cord Blood is validated as an alternative stem cell source allowing less HLA restriction for patients with malignant diseases. Besides the classical HLA matching, KIR genes form an independent diverse immunogenetic system that seems to have a significant influence on the outcome of allogeneic HSCT, especially the presence of B genotypes in the donor. Thus, the question rises on the possible value of KIR genotyping of prospective donors as an additional selection criterion. The aim of this study was to examine the diversity of the KIR repertoire of the HCBB (Hellenic Cord Blood Bank) inventory in comparison to previously documented favorable gene content (Cooley et al, 2010). Methods For this reason KIR genotyping of 320 CBU, for the presence of 14 KIR genes was performed, by PCR-SSO/SSP. Results The results revealed that 72.8% (233/320) of the donors had a Bx KIR genotype, while the remainder had the AA, which agreed with previously published KIR haplotype frequencies of the Greek population. When Bx KIR genotype content was further analyzed, 82.4% (192/233) of the CBUs had both KIR 2DL2/2DS2 (which may be independently advantageous), while 17.6% (41/233) had neither. On the other hand, the great variability of Bx genotypes observed in our inventory, indicates that units could be classified on the basis of a KIR B content score, in order to find a matching unit with the most favorable KIR gene content for a given patient. Conclusions In conclusion, adopting KIR genotyping could maximize the chance of identifying the optimal unit, out of several HLA-matched CBUs in our inventory, and would also be very attractive to incorporate in a unit selection algorithm in the future. It could become an additional service offered by the HCBB, which already offers high quality units that meet the highest standards in regards to TNC dose, CD34+ and CFU counts, HLA typing for HLA-A,-B,-DRB1 of both CBUs and mothers (making matching for NIMAs possible) and undergo all the required testing.
Annals of Plastic Surgery, 2013
ABSTRACT BACKGROUND: Diabetes can lead to impaired wound healing and skin grafts used surgically ... more ABSTRACT BACKGROUND: Diabetes can lead to impaired wound healing and skin grafts used surgically for diabetic wounds are often complicated with necrosis, although different therapies have been proposed. Adipose-derived stem cells (ASCs) participate in tissue repair processes and may have a role during impaired wound healing. In this study, autologous transplantation of ASCs was used to determine if it increases angiogenesis and skin graft survival and enhances wound healing in diabetic rats. METHODS: Adipose-derived stem cells were successfully isolated and cultured. A full-thickness skin graft model was used to determine the effects of locally administered ASCs in 10 rats rendered diabetic (group 1), whereas 10 others served as controls (group 2). Histological examination of skin grafts followed after 1 week. Additionally, immunohistochemical staining intensity of vascular endothelial growth factor (VEGF) and transforming growth factor β3 (TGF-β3) was assessed in all grafts. RESULTS: The gross and histological results showed significantly increased survival, angiogenesis, and epithelialization. Mean area of graft necrosis was significantly less in group 1 than in group 2 (7.49% vs 39.67%, P < 0.001). Statistically significant increase of capillary density, collagen intensity, VEGF, and TGF-β3 expression was noted in group 1 compared with group 2. CONCLUSIONS: These findings suggest that autologous ASC transplantation can enhance skin graft survival in diabetic rats through differentiation, vasculogenesis, and secretion of growth factors such as VEGF and TGF-β3. This might represent a novel therapeutic approach in skin graft surgery for diabetic wounds.
Cord Blood Stem Cells and Regenerative Medicine, 2015
Abstract The recent advances in regenerative medicine, tissue engineering, and cellular therapies... more Abstract The recent advances in regenerative medicine, tissue engineering, and cellular therapies combined with a better understanding of stem cell biology, have increased the demand for easily accessible, high-quality, clinical grade stem cells. Cord blood, routinely collected for autologous or allogeneic use, could meet this demand. This biological material is stored in cord blood banks, fully controlled, and human leukocyte antigen-typed, ready to use. Most importantly it can be a valuable source for stem cell populations such as endothelial progenitor cells and mesenchymal stem cells or even serve for the generation of induced pluripotent stem cells. Umbilical cord blood presents the advantage of being particularly rich in immature progenitors, which demonstrate a great expansion capacity. In addition, cord blood is derived shortly after birth and is less likely to contain potentially deleterious mutations than cells derived from adult tissues. Professional stem cell banks can provide qualified sources of cells and advice to help researchers and clinicians meet these demands and avoid wasted time due to receipt of unsuitable cells.
Journal of Hematology, 2015
Background: Assessment of the umbilical cord blood (UCB) unit is a crucial issue in the hematopoi... more Background: Assessment of the umbilical cord blood (UCB) unit is a crucial issue in the hematopoietic stem cell transplantation. A cord blood bank (CBB) must ensure that the final product of transplantation is represented accurately from quality control (QC) products of the UCB unit. The use of a tube segment attached to the UCB unit as well as a separate 1.8 mL cryovial containing an identical aliquot of the cryopreserved UCB unit product was exposed to the same postprocessing freezing and storage conditions as the UCB unit. Eventually, the utility of the attached segment and the 1.8 mL cryovial was evaluated as valid QC tools in order the final UCB unit graft to be validated. Methods: A total of 30 cord blood (CB) units, stored in liquid nitrogen, with their attached segments and 1.8 mL cryovials were thawed and several QC parameters (total nucleated cells (TNCs), CD34 + cells, CD133 + cells, percent viability and recovery) were obtained. Functional tests such as clonogenic assays were also performed. Results: Non-statistical differences were observed between UCB units, attached segments and 1.8 mL cryovials for any of the examined parameters. The expected clonogenic efficiency (ECLONE) was above 80% for all the three kinds of thawed samples (UCB unit, attached segment and QC sample). Conclusions: The QC of attached segment and 1.8 mL cryovial linked to the cryopreserved UCB unit may be used as a means to predict the potency and functionality of the actual UCB unit before transplantation.
Transfusion, 2014
Mesenchymal stem or stromal cells (MSCs) are a heterogeneous population that can be isolated from... more Mesenchymal stem or stromal cells (MSCs) are a heterogeneous population that can be isolated from many tissues including umbilical cord Wharton&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s jelly (UC-WJ). Although initially limited in studies such as a hematopoietic stem cell transplantation adjuvant, an increasing number of clinical trials consider MSCs as a potential anti-inflammatory or a regenerative medicine agent. It has been proposed that creating a repository of MSCs would increase their availability for clinical applications. The aim of this study was to assess the optimal isolation and cryopreservation procedures to facilitate WJ MSC banking. Cells were isolated from UC-WJ using enzymatic digestion or plastic adhesion methods. Their isolation efficacy, growth kinetics, immunophenotype, and differentiation potential were studied, as well as the effects of freezing. Flow cytometry for common MSC markers was performed on all cases and differentiation was shown with histocytochemical staining. Finally, the isolation efficacy on cryopreserved WJ tissue fragments was tested. MSC isolation was successful using both isolation methods on fresh UC-WJ tissue. However, UC-WJ MSC isolation from frozen tissue fragments was impossible. Flow cytometry analysis revealed that only MSC markers were expressed on the surface of the isolated cells while differentiation assays showed that they were capable of trilinear differentiation. All the above characteristics were also preserved in isolated UC-WJ MSCs over the cryopreservation study period. These data showed that viable MSCs can only be isolated from fresh UC-WJ tissue, setting the foundation for clinical-grade banking.
Cord Blood Stem Cells and Regenerative Medicine, 2015
Nature, Oct 1, 1985
Specific chromosomal translocations have been observed in several human and animal tumours and ar... more Specific chromosomal translocations have been observed in several human and animal tumours and are believed to be important in tumorigenesis1,2. In many of these translocations the breakpoints lie near cellular homologues of transforming genes, suggesting that tumour development is partly due to the activation of these genes. The best-characterized example of such a translocation occurs in mouse plasmacytoma and human B-cell lymphoma, where c-myc, the cellular homologue of the viral oncogene myc, is brought into close proximity with either the light- or heavy-chain genes of the immunoglobulin loci3-6, resulting in a change in the regulation of the myc gene7. T-cell malignancies also have characteristic chromosomal abnormalities, many of which seem to involve the 14q11-14q13 region8-12. This region has recently been found to contain the α-chain genes of the human T-cell antigen receptor13-15. Here we determine more precisely the chromosome breakpoints in two patients whose leukaemic T cells contain reciprocal translocations between 11p13 and 14q13. Segregation analysis of somatic cell hybrids demonstrates that in both patients the breakpoints occur between the variable (V) and constant (C) region genes of the T-cell receptor α-chain locus, resulting in the translocation of the C-region gene from chromosome 14 to chromosome 11. As the 11p13 locus has been implicated in the development of Wilms' tumour16,17, it is possible that either the Wilms' tumour gene or a yet unidentified gene in this region is involved in tumorigenesis and is altered as a result of its translocation into the T-cell receptor α-chain locus.
Transplantation Proceedings, 2014
Major achievements in creating decellularized whole tissue scaffolds have drawn considerable atte... more Major achievements in creating decellularized whole tissue scaffolds have drawn considerable attention to decellularization as a promising approach for tissue engineering. Developing a tissue-engineered small-diameter (2 mm) vascular graft, using decellularized human umbilical arteries (hUAs), for reconstructive surgery is a challenging task. Polymers used in the past, proved unsuitable due to serious adverse effects and autologous vessels are available only in 40% of patients. In this study, histological and proteomic analysis was performed to evaluate the efficiency of two decellularization protocols. In decellularization protocol A, hUAs were incubated in 3-[(3-cholamidopropyl) dimethylammonio]-1propanesulfonate (CHAPS) and sodium dodecyl sulfate (SDS) followed by incubation in alpha minimal essential medium (a-MEM) with foetal bovine serum (FBS) while in decellularization protocol B the hUAs were incubated in Hypotonic Tris and SDS followed by incubation in nuclease solution. Histological analysis of decelullarised hUA with both protocols revealed good preservation of extracellular cell matrix (ECM) proteins and immunofluorescent staining detected collagen I and fibronectin. The DNA content within the hUAs after decellularization with protocol A was 6.2% and with protocol B 17.3%. Proteomic analysis identified cytoplasmic enzymes such as, dehydrogenase X, a-enolase and peptidyl-prolyl cis-trans isomerase A only in native samples, while, cytoskeletal proteins such as a-actin, filamin and ECM proteins like collagens were found both in native and decellularised hUA. In conclusion, both decellularization protocols effectively removed the cellular material while the ECM remained intact. Future studies are warranted to elucidate the specific effects of altered structureefunction relationships on the overall fate of decellularized hUAs.
Proceedings of the National Academy of Sciences, 1988
In this paper we describe the genomic organization and sequence of the human T-cell receptor delt... more In this paper we describe the genomic organization and sequence of the human T-cell receptor delta-chain diversity, joining, and constant genes. There is one delta-chain constant region gene (C delta) located approximately equal to 85 kilobases (kb) upstream of the alpha-chain constant region. The delta-chain constant region consists of four exons, whose organization is very similar to that of the C alpha exons, suggesting that C alpha and C delta may have arisen from a gene duplication event. The first exon encodes most of the extracellular constant domain, the second encodes a hinge-like region, and the third encodes the entire transmembrane segment and intracytoplasmic portion, whereas the last exon contains exclusively 3' untranslated sequences. Three joining segments, J delta 1, J delta 2, and J delta 3, are found approximately equal to 12, approximately equal to 5.7, and approximately equal to 3.4 kb upstream of the first exon of C delta. Two functional diversity gene segments, D delta 1 and D delta 2, which can be productively translated in all three reading frames, are found 1 and 9.6 kb upstream of J delta 1. The presence of two D delta with such potential for diversity may offset the limited repertoire of the J delta and V delta genes. The spacer distribution in the recombinational signals flanking D delta and J delta segments allows recombination with V alpha gene segments; however, examination of delta-chain messages does not indicate that this is the case, suggesting that the delta chain uses unique variable gene segments and raising the question as to the reasons for this phenomenon.
Graefe's Archive for Clinical and Experimental Ophthalmology, 1988
A case of orbital cellulitis caused by mucormycosis developed in a patient subsequent to cataract... more A case of orbital cellulitis caused by mucormycosis developed in a patient subsequent to cataract extraction and during systemic steroid treatment for postoperative complications. Fatal mucormycosis is a rare disease usually beginning with a subcutaneous inflammatory lesion. As the subsequent development of orbital cellulitis is very rare, little has been published on this subject. In cases of subcutaneous mucormycosis, the diagnosis can easily be made by means of histologic examination of the lesion. However, early diagnosis is difficult in cases with orbital involvement, because the most common cause of orbital cellulitis is bacterial. Thus, orbital cellulitis caused by mucormycosis is often wrongly treated with antibacterial agents only, as histologic examination is neither easy nor part of any routine investigation. Therefore, a combined treatment using antibiotics and antifungal agents in immunusuppressed patients with this disease is advocated.
Human Reproduction
Study question This study aimed to the evaluation of PRP injection in women with ovarian dysfunct... more Study question This study aimed to the evaluation of PRP injection in women with ovarian dysfunction (with POR, POI, perimenopause and menopause) to promote the ovarian rejuvenation. Summary answer Intraovarian infusion of autologous PRP exhibited remarkable evidence and promising results to restore ovarian insufficiency. What is known already Ovarian dysfunctions, such as premature ovarian insufficiency (POI) and poor ovarian response (POR) are conditions, characterized by the collapse of ovarian function and are considered currently as a global public health issue. Primary factors that are associated with female infertility include endocrine dysfunction, failure of embryo implantation, endometriosis, and other related pathologies such as polycystic ovary syndrome (PCOS), various environmental factors and inflammatory disease. For this purpose, the rejuvenation of the ovaries using the intraovarian PRP injections may result in increased release of follicles from the available reser...
Transplantation Proceedings, 2015
ABSTRACT The loss or damage of an organ or tissue is one of the most common and devastating probl... more ABSTRACT The loss or damage of an organ or tissue is one of the most common and devastating problems in healthcare today. Tissue engineering applies the principles of engineering and biology toward the development of functional biological replacements that are able to maintain, improve, or restore the function of pathological tissues. The aim of the overall project is to study an already existing method for the decellularization of homograft vascular grafts for use in vascular surgery. The biomechanical integrity of native and decellularized rat aortas was assessed under uniaxial tension tests. For this purpose, 36 male rats (12 Wistar and 24 Dark Agouti [DA]) were used to excise their abdominal aortas. Twelve of the aortas were tested fresh (Wistar and DA rats), within 24 hours from euthanasia, and the rest were decellularized using a modified protocol (DA rats only). Fresh and decellularized samples (n = 12) were subjected to uniaxial tensile loading to failure, and the recorded stress-strain behaviour of each specimen was assessed in terms of 6 biomechanical parameters. No statistically significant differences were found in any of the biomechanical parameters studied between the decellularized DA rat aorta group and both the native DA and Wistar rat aorta groups (P > .05). Also, no significant difference was shown between the native DA and native Wistar rat aorta groups. The results from this study have shown that the decellularization protocol did not affect the mechanical properties of the native rat aorta. In addition to this, both native Wistar and native/decellularized DA rat aorta groups shared similar mechanical properties. Copyright © 2015 Elsevier Inc. All rights reserved.
Cord Blood Stem Cells and Regenerative Medicine, 2015
Abstract With the emergence of cord blood banking, arose concerns about whether cord blood units ... more Abstract With the emergence of cord blood banking, arose concerns about whether cord blood units stored in the banks were safe and effective as therapeutic products. These concerns led to the development of cord blood banking standards and establishment of quality programs in cord blood banks (CBBs). The notion of “quality” in CBBs is essential to ensure that all processes and systems in CBBs produce clinical quality cord blood units that are safe and effective for transplantation. These processes cover all aspects of collection, processing, cryopreservation, storage, disposal, selection, release and shipping of the cord blood units. The development/implementation of a quality management program and the final accreditation of cord blood banks/transplant programs can set the framework for the establishment of effective promotional strategies, which will control and certify all the possible factors which lead to a successful cord blood transplantation.
Transfusion, 2013
BACKGROUND: Cord blood (CB) units are stored from weeks to years in liquid-or vapor-phase nitroge... more BACKGROUND: Cord blood (CB) units are stored from weeks to years in liquid-or vapor-phase nitrogen until they are used for transplantation. We examined the effects of cryostorage in a mechanical freezer at-150°C on critical quality control variables of CB collections to investigate the possible use of mechanical freezers at-150°C as an alternative to storage in liquid-(or vapor-) phase nitrogen. STUDY DESIGN AND METHODS: A total of 105 CB units were thawed and washed at different time intervals (6, 12, 24, and 36 months). For every thawed CB unit, samples were removed and cell enumeration (total nucleated cells [TNCs], mononuclear cells [MNCs], CD34+, CD133+) was performed. In addition, viability was obtained with the use of flow cytometry, and recoveries were calculated. Also, total absolute colonyforming unit counts were performed and progenitor cell recoveries were studied by clonogenic assays. RESULTS: Significant differences (p < 0.05) were observed in certain variables (TNCs, MNC numbers, viability) when they were examined in relation with time intervals, while others (CD34+, CD133+) were relatively insensitive (p = NS) to the duration of time interval the CB units were kept in cryostorage condition. CONCLUSIONS: The data presented suggest that cryopreservation of CB units in a mechanical freezer at-150°C may represent an alternative cryostorage condition for CB cryopreservation. ABBREVIATIONS: BM = bone marrow; CB = cord blood; HSC(s) = hematopoietic stem cell(s); TNC(s) = total nucleated cell(s); UCB = umbilical cord blood.
Human Immunology, 2012
Aim Umbilical Cord Blood is validated as an alternative stem cell source allowing less HLA restri... more Aim Umbilical Cord Blood is validated as an alternative stem cell source allowing less HLA restriction for patients with malignant diseases. Besides the classical HLA matching, KIR genes form an independent diverse immunogenetic system that seems to have a significant influence on the outcome of allogeneic HSCT, especially the presence of B genotypes in the donor. Thus, the question rises on the possible value of KIR genotyping of prospective donors as an additional selection criterion. The aim of this study was to examine the diversity of the KIR repertoire of the HCBB (Hellenic Cord Blood Bank) inventory in comparison to previously documented favorable gene content (Cooley et al, 2010). Methods For this reason KIR genotyping of 320 CBU, for the presence of 14 KIR genes was performed, by PCR-SSO/SSP. Results The results revealed that 72.8% (233/320) of the donors had a Bx KIR genotype, while the remainder had the AA, which agreed with previously published KIR haplotype frequencies of the Greek population. When Bx KIR genotype content was further analyzed, 82.4% (192/233) of the CBUs had both KIR 2DL2/2DS2 (which may be independently advantageous), while 17.6% (41/233) had neither. On the other hand, the great variability of Bx genotypes observed in our inventory, indicates that units could be classified on the basis of a KIR B content score, in order to find a matching unit with the most favorable KIR gene content for a given patient. Conclusions In conclusion, adopting KIR genotyping could maximize the chance of identifying the optimal unit, out of several HLA-matched CBUs in our inventory, and would also be very attractive to incorporate in a unit selection algorithm in the future. It could become an additional service offered by the HCBB, which already offers high quality units that meet the highest standards in regards to TNC dose, CD34+ and CFU counts, HLA typing for HLA-A,-B,-DRB1 of both CBUs and mothers (making matching for NIMAs possible) and undergo all the required testing.
Annals of Plastic Surgery, 2013
ABSTRACT BACKGROUND: Diabetes can lead to impaired wound healing and skin grafts used surgically ... more ABSTRACT BACKGROUND: Diabetes can lead to impaired wound healing and skin grafts used surgically for diabetic wounds are often complicated with necrosis, although different therapies have been proposed. Adipose-derived stem cells (ASCs) participate in tissue repair processes and may have a role during impaired wound healing. In this study, autologous transplantation of ASCs was used to determine if it increases angiogenesis and skin graft survival and enhances wound healing in diabetic rats. METHODS: Adipose-derived stem cells were successfully isolated and cultured. A full-thickness skin graft model was used to determine the effects of locally administered ASCs in 10 rats rendered diabetic (group 1), whereas 10 others served as controls (group 2). Histological examination of skin grafts followed after 1 week. Additionally, immunohistochemical staining intensity of vascular endothelial growth factor (VEGF) and transforming growth factor β3 (TGF-β3) was assessed in all grafts. RESULTS: The gross and histological results showed significantly increased survival, angiogenesis, and epithelialization. Mean area of graft necrosis was significantly less in group 1 than in group 2 (7.49% vs 39.67%, P < 0.001). Statistically significant increase of capillary density, collagen intensity, VEGF, and TGF-β3 expression was noted in group 1 compared with group 2. CONCLUSIONS: These findings suggest that autologous ASC transplantation can enhance skin graft survival in diabetic rats through differentiation, vasculogenesis, and secretion of growth factors such as VEGF and TGF-β3. This might represent a novel therapeutic approach in skin graft surgery for diabetic wounds.
Cord Blood Stem Cells and Regenerative Medicine, 2015
Abstract The recent advances in regenerative medicine, tissue engineering, and cellular therapies... more Abstract The recent advances in regenerative medicine, tissue engineering, and cellular therapies combined with a better understanding of stem cell biology, have increased the demand for easily accessible, high-quality, clinical grade stem cells. Cord blood, routinely collected for autologous or allogeneic use, could meet this demand. This biological material is stored in cord blood banks, fully controlled, and human leukocyte antigen-typed, ready to use. Most importantly it can be a valuable source for stem cell populations such as endothelial progenitor cells and mesenchymal stem cells or even serve for the generation of induced pluripotent stem cells. Umbilical cord blood presents the advantage of being particularly rich in immature progenitors, which demonstrate a great expansion capacity. In addition, cord blood is derived shortly after birth and is less likely to contain potentially deleterious mutations than cells derived from adult tissues. Professional stem cell banks can provide qualified sources of cells and advice to help researchers and clinicians meet these demands and avoid wasted time due to receipt of unsuitable cells.
Journal of Hematology, 2015
Background: Assessment of the umbilical cord blood (UCB) unit is a crucial issue in the hematopoi... more Background: Assessment of the umbilical cord blood (UCB) unit is a crucial issue in the hematopoietic stem cell transplantation. A cord blood bank (CBB) must ensure that the final product of transplantation is represented accurately from quality control (QC) products of the UCB unit. The use of a tube segment attached to the UCB unit as well as a separate 1.8 mL cryovial containing an identical aliquot of the cryopreserved UCB unit product was exposed to the same postprocessing freezing and storage conditions as the UCB unit. Eventually, the utility of the attached segment and the 1.8 mL cryovial was evaluated as valid QC tools in order the final UCB unit graft to be validated. Methods: A total of 30 cord blood (CB) units, stored in liquid nitrogen, with their attached segments and 1.8 mL cryovials were thawed and several QC parameters (total nucleated cells (TNCs), CD34 + cells, CD133 + cells, percent viability and recovery) were obtained. Functional tests such as clonogenic assays were also performed. Results: Non-statistical differences were observed between UCB units, attached segments and 1.8 mL cryovials for any of the examined parameters. The expected clonogenic efficiency (ECLONE) was above 80% for all the three kinds of thawed samples (UCB unit, attached segment and QC sample). Conclusions: The QC of attached segment and 1.8 mL cryovial linked to the cryopreserved UCB unit may be used as a means to predict the potency and functionality of the actual UCB unit before transplantation.
Transfusion, 2014
Mesenchymal stem or stromal cells (MSCs) are a heterogeneous population that can be isolated from... more Mesenchymal stem or stromal cells (MSCs) are a heterogeneous population that can be isolated from many tissues including umbilical cord Wharton&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s jelly (UC-WJ). Although initially limited in studies such as a hematopoietic stem cell transplantation adjuvant, an increasing number of clinical trials consider MSCs as a potential anti-inflammatory or a regenerative medicine agent. It has been proposed that creating a repository of MSCs would increase their availability for clinical applications. The aim of this study was to assess the optimal isolation and cryopreservation procedures to facilitate WJ MSC banking. Cells were isolated from UC-WJ using enzymatic digestion or plastic adhesion methods. Their isolation efficacy, growth kinetics, immunophenotype, and differentiation potential were studied, as well as the effects of freezing. Flow cytometry for common MSC markers was performed on all cases and differentiation was shown with histocytochemical staining. Finally, the isolation efficacy on cryopreserved WJ tissue fragments was tested. MSC isolation was successful using both isolation methods on fresh UC-WJ tissue. However, UC-WJ MSC isolation from frozen tissue fragments was impossible. Flow cytometry analysis revealed that only MSC markers were expressed on the surface of the isolated cells while differentiation assays showed that they were capable of trilinear differentiation. All the above characteristics were also preserved in isolated UC-WJ MSCs over the cryopreservation study period. These data showed that viable MSCs can only be isolated from fresh UC-WJ tissue, setting the foundation for clinical-grade banking.
Cord Blood Stem Cells and Regenerative Medicine, 2015
Nature, Oct 1, 1985
Specific chromosomal translocations have been observed in several human and animal tumours and ar... more Specific chromosomal translocations have been observed in several human and animal tumours and are believed to be important in tumorigenesis1,2. In many of these translocations the breakpoints lie near cellular homologues of transforming genes, suggesting that tumour development is partly due to the activation of these genes. The best-characterized example of such a translocation occurs in mouse plasmacytoma and human B-cell lymphoma, where c-myc, the cellular homologue of the viral oncogene myc, is brought into close proximity with either the light- or heavy-chain genes of the immunoglobulin loci3-6, resulting in a change in the regulation of the myc gene7. T-cell malignancies also have characteristic chromosomal abnormalities, many of which seem to involve the 14q11-14q13 region8-12. This region has recently been found to contain the α-chain genes of the human T-cell antigen receptor13-15. Here we determine more precisely the chromosome breakpoints in two patients whose leukaemic T cells contain reciprocal translocations between 11p13 and 14q13. Segregation analysis of somatic cell hybrids demonstrates that in both patients the breakpoints occur between the variable (V) and constant (C) region genes of the T-cell receptor α-chain locus, resulting in the translocation of the C-region gene from chromosome 14 to chromosome 11. As the 11p13 locus has been implicated in the development of Wilms' tumour16,17, it is possible that either the Wilms' tumour gene or a yet unidentified gene in this region is involved in tumorigenesis and is altered as a result of its translocation into the T-cell receptor α-chain locus.
Transplantation Proceedings, 2014
Major achievements in creating decellularized whole tissue scaffolds have drawn considerable atte... more Major achievements in creating decellularized whole tissue scaffolds have drawn considerable attention to decellularization as a promising approach for tissue engineering. Developing a tissue-engineered small-diameter (2 mm) vascular graft, using decellularized human umbilical arteries (hUAs), for reconstructive surgery is a challenging task. Polymers used in the past, proved unsuitable due to serious adverse effects and autologous vessels are available only in 40% of patients. In this study, histological and proteomic analysis was performed to evaluate the efficiency of two decellularization protocols. In decellularization protocol A, hUAs were incubated in 3-[(3-cholamidopropyl) dimethylammonio]-1propanesulfonate (CHAPS) and sodium dodecyl sulfate (SDS) followed by incubation in alpha minimal essential medium (a-MEM) with foetal bovine serum (FBS) while in decellularization protocol B the hUAs were incubated in Hypotonic Tris and SDS followed by incubation in nuclease solution. Histological analysis of decelullarised hUA with both protocols revealed good preservation of extracellular cell matrix (ECM) proteins and immunofluorescent staining detected collagen I and fibronectin. The DNA content within the hUAs after decellularization with protocol A was 6.2% and with protocol B 17.3%. Proteomic analysis identified cytoplasmic enzymes such as, dehydrogenase X, a-enolase and peptidyl-prolyl cis-trans isomerase A only in native samples, while, cytoskeletal proteins such as a-actin, filamin and ECM proteins like collagens were found both in native and decellularised hUA. In conclusion, both decellularization protocols effectively removed the cellular material while the ECM remained intact. Future studies are warranted to elucidate the specific effects of altered structureefunction relationships on the overall fate of decellularized hUAs.
Proceedings of the National Academy of Sciences, 1988
In this paper we describe the genomic organization and sequence of the human T-cell receptor delt... more In this paper we describe the genomic organization and sequence of the human T-cell receptor delta-chain diversity, joining, and constant genes. There is one delta-chain constant region gene (C delta) located approximately equal to 85 kilobases (kb) upstream of the alpha-chain constant region. The delta-chain constant region consists of four exons, whose organization is very similar to that of the C alpha exons, suggesting that C alpha and C delta may have arisen from a gene duplication event. The first exon encodes most of the extracellular constant domain, the second encodes a hinge-like region, and the third encodes the entire transmembrane segment and intracytoplasmic portion, whereas the last exon contains exclusively 3' untranslated sequences. Three joining segments, J delta 1, J delta 2, and J delta 3, are found approximately equal to 12, approximately equal to 5.7, and approximately equal to 3.4 kb upstream of the first exon of C delta. Two functional diversity gene segments, D delta 1 and D delta 2, which can be productively translated in all three reading frames, are found 1 and 9.6 kb upstream of J delta 1. The presence of two D delta with such potential for diversity may offset the limited repertoire of the J delta and V delta genes. The spacer distribution in the recombinational signals flanking D delta and J delta segments allows recombination with V alpha gene segments; however, examination of delta-chain messages does not indicate that this is the case, suggesting that the delta chain uses unique variable gene segments and raising the question as to the reasons for this phenomenon.
Graefe's Archive for Clinical and Experimental Ophthalmology, 1988
A case of orbital cellulitis caused by mucormycosis developed in a patient subsequent to cataract... more A case of orbital cellulitis caused by mucormycosis developed in a patient subsequent to cataract extraction and during systemic steroid treatment for postoperative complications. Fatal mucormycosis is a rare disease usually beginning with a subcutaneous inflammatory lesion. As the subsequent development of orbital cellulitis is very rare, little has been published on this subject. In cases of subcutaneous mucormycosis, the diagnosis can easily be made by means of histologic examination of the lesion. However, early diagnosis is difficult in cases with orbital involvement, because the most common cause of orbital cellulitis is bacterial. Thus, orbital cellulitis caused by mucormycosis is often wrongly treated with antibacterial agents only, as histologic examination is neither easy nor part of any routine investigation. Therefore, a combined treatment using antibiotics and antifungal agents in immunusuppressed patients with this disease is advocated.