An International Society for Cell and Gene Therapy Mesenchymal Stromal Cells (MSC) Committee perspectives on International Standards Organization/Technical Committee 276 Biobanking Standards for bone marrow-MSCs and umbilical cord tissue-derived MSCs for research purposes.

The rapidly growing field of mesenchymal stromal cell (MSC) basic and translational research requires standardization of terminology and functional characterization. The International Standards Organization's (ISO) Technical Committee (TC) on Biotechnology, working with extensive input from the International Society for Cells and Gene Therapy (ISCT), has recently published ISO standardization documents that are focused on biobanking of MSCs from two tissue sources, Wharton's Jelly, MSC(WJ) and Bone Marrow, MSC(M)), for research and development purposes and development. This manuscript explains the path towards the consensus on the following two documents: the Technical Standard ISO/TS 22859 for MSC(WJ) and the full ISO Standard 24651 for MSC(M) biobanking. The ISO standardization documents are aligned with ISCT's MSC committee position and recommendations on nomenclature because there was active input and incorporation of ISCT MSC committee recommendations in the development of these standards. The ISO standardization documents contain both requirements and recommendations for functional characterization of MSC(WJ) and MSC(M) using a matrix of assays. Importantly, the ISO standardization documents have a carefully defined scope and are meant for research use of culture expanded MSC(WJ) and MSC(M). The ISO standardization documents can be updated in a revision process and will be systematically reviewed after 3-5 years as scientific insights grow. They represent international consensus on MSC identity, definition, and characterization; are rigorous in detailing multivariate characterization of MSCs and represent an evolving-but-important first step in standardization of MSC biobanking and characterization for research use and development.

Phenotypic and Functional Alterations of Hematopoietic Stem and Progenitor Cells in an In Vitro Leukemia-Induced Microenvironment.

An understanding of the cell interactions occurring in the leukemic microenvironment and their functional consequences for the different cell players has therapeutic relevance. By co-culturing mesenchymal stem cells (MSC) with the REH acute lymphocytic leukemia (ALL) cell line, we have established an in vitro leukemic niche for the functional evaluation of hematopoietic stem/progenitor cells (HSPC, CD34+ cells). We showed that the normal homeostatic control exerted by the MSC over the HSPC is considerably lost in this leukemic microenvironment: HSPC increased their proliferation rate and adhesion to MSC. The adhesion molecules CD54 and CD44 were consequently upregulated in HSPC from the leukemic niche. Consequently, with this adhesive phenotype, HSPC showed less Stromal derived factor-1 (SDF-1)-directed migration. Interestingly, multipotency was severely affected with an important reduction in the absolute count and the percentage of primitive progenitor colonies. It was possible to simulate most of these HSPC alterations by incubation of MSC with a REH-conditioned medium, suggesting that REH soluble factors and their effect on MSC are important for the observed changes. Of note, these HSPC alterations were reproduced when primary leukemic cells from an ALL type B (ALL-B) patient were used to set up the leukemic niche. These results suggest that a general response is induced in the leukemic niche to the detriment of HSPC function and in favor of leukemic cell support. This in vitro leukemic niche could be a valuable tool for the understanding of the molecular events responsible for HSPC functional failure and a useful scenario for therapeutic evaluation.

Mesenchymal stem cells promote a primitive phenotype CD34+c-kit+ in human cord blood-derived hematopoietic stem cells during ex vivo expansion.

The purpose of this study was to evaluate the influence of bone marrow-mesenchymal stem cells (BM-MSC) and exogenously added cytokines on the proliferation, primitive cell subpopulation maintenance (including the c-kit+ marker) and clonogenic capacity of hematopoietic stem cells (HSC). BM-MSC were collected from volunteer donors, isolated and characterized. Umbilical cord blood (UCB) samples were collected from healthy full-term deliveries. UCB-CD34+ cells were cultured in the presence or absence of BM-MSC and/or cytokines for 3 and 7 days. CD34+ cell proliferation was evaluated using the CSFE method and cell phenotype was determined by CD34, c-kit, CD33, CD38, HLA-DR, cyCD22 and cyCD3 detection. Cell clonogenic ability was also assessed. Exogenously added SCF, TPO and FLT3L increased CD34+ cell proliferation in the presence or absence of BM-MSC, but with concomitant cell differentiation. Without any added cytokines, BM-MSC are able to increase the percentage of primitive progenitors as evaluated by c-kit expression and CFU-GEMM increase. Interestingly, this latter effect was dependent on both cell-cell interactions and secreted factors. A 7-day co-culture period will be optimal for obtaining an increased primitive HSC level. Including c-kit as a marker for primitive phenotype evaluation has shown the relevance of BM-MSC and their secreted factors on UCB-HSC stemness function. This effect could be dissociated from that of the addition of exogenous cytokines, which induced cellular differentiation instead.

Plant extract from Caesalpinia spinosa inhibits cancer-associated fibroblast-like cells generation and function in a tumor microenvironment model.

Interactions in the tumor microenvironment (TME) between tumor cells and stromal cells such as cancer-associated fibroblasts (CAF) favor increased survival, progression, and transformation of cancer cells by activating mechanisms of invasion and metastasis. The design of new therapies to modulate or eliminate the CAF phenotype or functionality has been the subject of recent research including natural product-based therapies. We have previously described the generation of a standardized extract rich in polyphenols obtained from the Caesalpinia spinosa plant (P2Et), which present antitumor activities in breast cancer and melanoma models through activities that modulate the metabolism of tumor cells or induce the development of the immune response. In this work, a model of CAF generation was initially developed from the exposure of 3T3 fibroblasts to the cytokine TGFß1. CAF-like cells generated in this way exhibited changes in the expression of Caveolin-1 and α-SMA, and alterations in glucose metabolism and redox status, typical of CAFs isolated from tumor tissues. Then, P2Et was shown to counteract in vitro-induced CAF-like cell generation, preventing caveolin-1 loss and attenuating changes in glucose uptake and redox profile. This protective effect of P2Et translates into a decrease in the functional ability of CAFs to support colony formation and migration of 4T1 murine breast cancer tumor cells. In addition to the functional interference, the P2Et extract also decreased the expression of genes associated with the epithelial-mesenchymal transition (EMT) and functional activities related to the modulation of the cancer stem cells (CSC) population. This work is an in vitro approach to evaluate natural extracts' effect on the interaction between CAF and tumor cells in the tumor microenvironment; thus, these results open the chance to design a more profound and mechanistic analysis to explore the molecular mechanisms of P2Et multimolecular activity and extent this analysis to an in vivo perspective. In summary, we present here a standardized polymolecular natural extract that has the potential to act in the TME by interfering with CAF generation and functionality.

Doxorubicin Activity Is Modulated by Traditional Herbal Extracts in a 2D and 3D Multicellular Sphere Model of Leukemia.

The modulation of the tumor microenvironment by natural products may play a significant role in the response of tumor cells to chemotherapy. In this study, we evaluated the effect of extracts derived from P2Et (Caesalpinia spinosa) and Anamú-SC (Petiveria alliacea) plants, previously studied by our group, on the viability and ROS levels in the K562 cell line (Pgp- and Pgp+), endothelial cells (ECs, Eahy.926 cell line) and mesenchymal stem cells (MSC) cultured in 2D and 3D. The results show that: (a) the two botanical extracts are selective on tumor cells compared to doxorubicin (DX), (b) cytotoxicity is independent of the modulation of intracellular ROS for plant extracts, unlike DX, (c) the interaction with DX can be influenced by chemical complexity and the expression of Pgp, (d) the 3D culture shows a greater sensitivity of the tumor cells to chemotherapy, in co-treatment with the extracts. In conclusion, the effect of the extracts on the viability of leukemia cells was modified in multicellular spheroids with MSC and EC, suggesting that the in vitro evaluation of these interactions can contribute to the comprehension of the pharmacodynamics of the botanical drugs.

3D Multicellular Spheroid for the Study of Human Hematopoietic Stem Cells: Synergistic Effect Between Oxygen Levels, Mesenchymal Stromal Cells and Endothelial Cells.

INTRODUCTION: The human bone marrow microenvironment is composed of biological, chemical and physical factors that act in a synergistic way to modulate hematopoietic stem cell biology, such as mesenchymal stromal cells (MSCs), endothelial cells (ECs) and low oxygen levels; however, it is difficult to mimic this human microenvironment in vitro. METHODS: In this work, we developed 3D multicellular spheroid (3D-MS) for the study of human hematopoietic stem cells (HSCs) with some components of perivascular niche. HSCs were isolated from umbilical cord blood, MSCs were isolated from human bone marrow and a microvasculature EC line (CC-2811, Lonza®) was used. For the formation of a 3D structure, a magnetic levitation culture system was used. Cultures were maintained in 21%, 3% and 1% O2 for 15 days. Culture volume, sphericity index and cell viability were determined. Also, human HSC proliferation, phenotype and production of reactive oxygen species were evaluated. RESULTS: After 15 days, 3D-MS exhibited viability greater than 80%. Histology results showed structures without necrotic centers, and higher cellular proliferation with 3% O2. An increase in the expression of the CD34 antigen and other hematopoietic antigens were observed to 1% O2 with MSCs plus ECs and low ROS levels. CONCLUSION: These findings suggest that 3D-MS formed by MSCs, ECs and HSCs exposed to low concentrations of oxygen (1-3% O2) modulate human HSC behavior and mimics some features of the perivascular niche, which could reduce the use of animal models and deepen the relationship between the microenvironment of HSC and human hematological diseases development.

TRPM8 Channel Promotes the Osteogenic Differentiation in Human Bone Marrow Mesenchymal Stem Cells.

Various families of ion channels have been characterized in mesenchymal stem cells (MSCs), including some members of transient receptor potential (TRP) channels family. TRP channels are involved in critical cellular processes as differentiation and cell proliferation. Here, we analyzed the expression of TRPM8 channel in human bone marrow MSCs (hBM-MSCs), and its relation with osteogenic differentiation. Patch-clamp recordings showed that hBM-MSCs expressed outwardly rectifying currents which were increased by exposure to 500 µM menthol and were partially inhibited by 10 µM of BCTC, a TRPM8 channels antagonist. Additionally, we have found the expression of TRPM8 by RT-PCR and western blot. We also explored the TRPM8 localization in hBM-MSCs by immunofluorescence using confocal microscopy. Remarkably, hBM-MSCs treatment with 100 µM of menthol or 10 µM of icilin, TRPM8 agonists, increases osteogenic differentiation. Conversely, 20 µM of BCTC, induced a decrease of osteogenic differentiation. These results suggest that TRPM8 channels are functionally active in hBM-MSCs and have a role in cell differentiation.

Generation of Organotypic Multicellular Spheres by Magnetic Levitation: Model for the Study of Human Hematopoietic Stem Cells Microenvironment.

BACKGROUND AND OBJECTIVE: The characteristics of human hematopoietic stem cells are conditioned by the microenvironment of the bone marrow, where they interact with other cell populations, such as mesenchymal stem cells and endothelial cells; however, the study of this microenvironment is complex. The objective of this work was to develop a 3D culture system by magnetic levitation that imitates the microenvironment of human HSC. METHODS AND RESULTS: Human bone marrow-mesenchymal stem cells, umbilical cord blood-hematopoietic stem cells and a non-tumoral endothelial cell line (CC2811, LonzaⓇ) were used to develop organotypic multicellular spheres by the magnetic levitation method. We obtained viable structures with an average sphericity index greater than 0.6, an average volume of 0.5 mm3 and a percentage of aggregation greater than 70%. Histological studies of the organotypic multicellular spheres used hematoxylin and eosin stains, and an evaluation of vimentin expression by means of immunohistochemistry demonstrated an organized internal structure without picnotic cells and a high expression of vimentin. The functional capacity of human hematopoietic stem cells after organotypic multicellular spheres culture was evaluated by multipotency tests, and it was demonstrated that 3D structures without exogenous Flt3L are autonomous in the maintenance of multipotency of human hematopoietic stem cells. CONCLUSIONS: We developed organotypic multicellular spheres from normal human cells that mimic the microenvironment of the human hematopoietic stem cells. These structures are the prototype for the development of complex organoids that allow the further study of the biology of normal human stem cells and their potential in regenerative medicine.

Impact of donor characteristics on the quality of bone marrow as a source of mesenchymal stromal cells.

In recent years, the therapeutic use of mesenchymal stromal cells (MSC) has generated a valuable number of scientific studies that delve into their biological characteristics and their potential in regenerative medicine; however, the impact of the clinical characteristics of tissue donors, from which these cells are isolated, on their potential in applied clinical research is not yet clear. The objective of this study was to evaluate the impact of the clinical characteristics of bone marrow donors on the quality of this tissue as a source of MSC for therapeutic use. Human MSC were isolated, characterized and cultured (according to ISCT criteria) from bone marrow samples from volunteer donors (n = 70) attending the Department of Orthopedics and Traumatology of the Hospital Universitario San Ignacio (Bogota, Colombia) for surgery of prosthetic hip replacement that agreed to participate voluntarily in the study. Donor data such as age, gender, weight, smoker and type of anesthesia used during the surgical procedure were recorded, and the impact of these characteristics on the volume of tissue collection, mononuclear cell count and confluence time of cells with fibroblastoid morphology was evaluated. Correlation coefficients between quantitative variables were calculated with Spearman's correlation test, and the association between qualitative and quantitative variables was evaluated with biserial correlation coefficient. A significant correlation was observed between the age of the donors and the time necessary to obtain confluent cells in vitro (r = 0.2489, P = 0.0377); similarly, the correlation between the volume of bone marrow collected and the number of mononuclear cells obtained was significant (r = 0.7101, P = 0.0001). Although a negative correlation tendency was observed between the mononuclear cell count and the confluence time, this was not significant (r = -0.2041, P = 0.0950). No significant associations were observed between gender, smoking status or type of anesthesia and the expansion characteristics of human mesenchymal stromal cells. Bone marrow donor age and the tissue collection volume impact the time of obtaining MSC in vitro and the mononuclear cell count with which the culture starts. These conditions must be considered when the bone marrow is selected as the tissue for obtaining MSC.

Mesenchymal stem cells promote leukaemic cells aberrant phenotype from B-cell acute lymphoblastic leukaemia.

BACKGROUND AND OBJECTIVES: The role of bone marrow-mesenchymal stem cells (BM-MSC) in leukaemic cell control is controversial. The purpose of this work was to evaluate BM-MSC role regarding the viability, proliferation and immunophenotype of normal B-cell precursors from control (Ct) patients and leukaemic cells from B-acute lymphoblastic leukaemia (B-ALL) patients. PATIENTS AND METHODS: BM-MSC were isolated and characterised from voluntary donors. Mononuclear cells isolated from Ct and B-ALL bone marrow samples were cultured in the presence or absence of BM-MSC for 7days. Cell viability was determined with LIVE/DEAD and proliferation index evaluated by CFSE labelling. Cell population immunophenotypes were characterised by estimating CD19, CD10, CD20 and CD45 antigens by flow cytometry. RESULTS: After co-culture, B-ALL cells exhibited higher viability (20-40%) as compared to just cells (3-10%). Ct and B-ALL absolute cell counts were higher in the presence of BM-MSC (Ct: 25/mm(3)cf8/mm(3), B-ALL: 15/mm(3)cf3/mm(3)). Normal B-cell subpopulations in co-culture had increased expression of CD19 and CD10 (Pre-pre B) and CD45 and CD20 antigens (Pre-B). B-ALL cells co-cultured with BM-MSC showed an increase in CD19 and CD20, although the greatest increase was observed in the CD10 antigen. CONCLUSIONS: Lymphoid cell maintenance, at early stages of differentiation, was significantly promoted by BM-MSC in normal and leukaemic cells. Co-cultures also modulated the expression of antigens associated with the B-ALL asynchronous phenotype as CD10 co-expressed with CD19 and CD20. To our knowledge, this is the first time that CD10, CD19 and CD20 leukaemic antigens have been reported as being regulated by BM-MSC.

Aislamiento y caracterización de células "stem" mesenquimales de médula ósea humana según criterios de la Sociedad Internacional de Terapia Celular / Isolation and characterization of mesenchymal stem cells from human bone marrow according to the criteria of the International Society for Cellular Therapy / Isolamento e caracterização de células-tronco mesenquimais de medula óssea humana de acordo com critérios da Sociedade Internacional de Terapia Celular

La médula ósea (MO) es una fuente importante para el aislamiento de células "stem" mesenquimales (CSM) útiles en terapias de regeneración tisular e inmunomodulación. Objetivo. Aislar y caracterizar células "stem" mesenquimales obtenidas de MO según los criterios exigidos por la Sociedad Internacional de Terapia Celular. Materiales y métodos. Se recolectaron muestras de MO de donantes voluntarios que asistían al Servicio de Ortopedia del Hospital Universitario San Ignacio, Bogotá (Colombia). Se evaluaron las características morfológicas por microscopia invertida y se determinó el inmunofenotipo por citometría de flujo. Se establecieron protocolos de inducción adipogénica, osteogénica y condrogénica mediante el uso de medios de cultivo de específicos y se evaluó la diferenciación utilizando tinciones de aceite rojo 'O', fosfatasa alcalina y safranina, respectivamente. Resultados. Se recolectaron 24 muestras de MO de pacientes sometidos a reemplazo total de cadera (volumen de muestra de MO: 5 - 45 ml). Se aislaron células con morfología fibroblastoide a partir de 21 muestras de MO (eficiencia de aislamiento: 87,5 %). En la determinación inmunofenotípica (CSM de MO) no existe diferencia estadísticamente significativa entre los antígenos hematopoyéticos (CD34 y CD45, p>0,05). Entre el antígeno hematopoyético CD45 y los antígenos mesenquimales (CD13, CD44, CD73, CD90, CD105, HLA-I y HLA-DR) existe diferencia estadísticamente significativa (p=0.006). La tinción de aceite rojo 'O' reveló la presencia de adipocitos multiloculares, en la inducción osteogénica se observaron centros de mineralización y la condrogénesis fue positiva para la coloración con safranina. Conclusión. A partir de MO se aislaron satisfactoriamente y caracterizaron CSM según los criterios internacionales exigidos.

Bone marrow (BM) is an important source for isolating mesenchymal stem cells (MSC) useful in immunomodulation and tissue regeneration therapies. Objective. To isolate and characterize mesenchymal stem cells obtained from BM meeting the requirements of the International Society for Cellular Therapy. Materials and methods. BM samples were collected from volunteer donors attending the Orthopedics Service of the San Ignacio University Hospital (Bogotá, Colombia). Morphological characteristics were evaluated by inverted microscopy and the immunophenotype was determined by flow cytometry. Protocols were developed for adipogenic, osteogenic and chondrogenic differentiation using the Oil Red O, alkaline phosphatase and safranin stains, respectively. Results. We collected 24 samples of BM from patients with total hip replacement (volume of BM sample: 5-45 ml). Cells with a fibroblastoid morphology were isolated from 21 BM samples (isolation efficiency: 87.5%). No statistical significant differences were found between the hematopoyetic antigens (CD34 and CD45, p>0.05) in the immunophenotypic evaluation (of MSC from BM); on the contrary, there were differences (p=0.006) between the hematopoyetic antigen CD45 and the mesenchymal antigens (CD13, CD44, CD73, CD90, CD105, HLA-I, and HLA-DR). Oil Red O stain revealed the presence of multilocular adipocytes, in the osteogenic induction we observed localized mineralization nodules, and chondrogenesis was positive as revealed by the safranin stain. Conclusion. MSC were satisfactorily isolated from BM and characterized according to the international standards.

A medula óssea (MO) é uma importante fonte para o isolamento de células-tronco mesenquimais (CTM) úteis na terapia de regeneração dos tecidos e imunomodulação. Objetivo. Isolar e caracterizar células-tronco mesenquimais obtidas de MO de acordo com os critérios exigidos pela Sociedade Internacional de Terapia Celular. Materiais e métodos. Foram coletadas amostras de MO de doadores voluntários que assistiram ao Serviço de Ortopedia do Hospital Universitário de São Ignacio, Bogotá (Colômbia). As características morfológicas foram avaliadas por microscopia invertida, e o imunofenótipo foi determinado por citometria de fluxo. Foram estabelecidos protocolos de indução adipogênica, osteogênica e condrogênica usando meios de cultura específicos e a diferenciação foi avaliada por meio da coloração com o "Oil Red O", fosfatase alcalina e safranina, respectivamente. Resultados. Foram coletadas 24 amostras de MO em pacientes submetidos â artroplastia total do quadril (volume de amostra de OM: 5 - 45 ml). Foram isoladas células com morfologia fibroblastóide a partir de 21 amostras de MO (eficiência de isolamento: 87,5%). Na determinação immunofenotípica (CTM de MO), não existe diferença estatisticamente significativa entre os antigénios hematopoiéticos (CD34 e CD45, p>0,05). Entre o antigénio hematopoiético CD45 e os antigénios mesenquimais (CD13, CD44, CD73, CD90, CD105, HLA-I e HLA-DR), existe diferença estatisticamente significativa (p =0,006). A coloração com o "Oil Red O" revelou a presença de adipócitos multiloculares, na indução osteogénica observaram-se centros de mineralização e a condrogênese foi positiva para a coloração com safranina. Conclusão. A partir de MO foram isoladas satisfatoriamente e caracterizaram CTM segundo os critérios internacionais exigidos.

Análisis inmunofenotípico de muestras normales de médula ósea: aplicaciones en el control de calidad en los laboratorios de citometría / Immunophenotypic analysis of normal cell samples from bone marrow: applications in quality control of cytometry laboratories / Análise imunofenotípica de amostras de medula óssea normal: aplicações no controle de qualidade em laboratórios de citometria

Objetivo. Describir un protocolo estandarizado mediante citometría de flujo para cuantificar en términos absolutos y relativos distintas subpoblaciones celulares de médula ósea normal y analizar la expresión de diferentes marcadores celulares específicos de linaje cuya reactividad está asociada a la diferenciación celular para ser usado como parte del control de calidad de rutina en los laboratorios de citometría. Materiales y métodos. El análisis inmunofenotípico de distintas subpoblaciones celulares se realizó en muestras de MO normal empleando un panel de anticuerpos monoclonales y policlonales útiles para la caracterización fenotípica de leucemias agudas en 4 fluorescencias distintas, con un protocolo que combina marcaje celular de antígenos de membrana y de citoplasma. El análisis de expresión se realizó en términos de intensidad media de fluorescencia. Para el cálculo de recuentos absolutos se adicionaron esferas fluorescentes de concentración conocida. Resultados. El panel de anticuerpos utilizado permitió la identificación y cuantificación de las distintas subpoblaciones leucocitarias normales de origen linfoide y mieloide incluyendo células precursoras CD34+, y poblaciones celulares más diferenciadas incluidas en las líneas granulocítica, monocítica y eritroide. Se establecieron los valores de referencia de las poblaciones celulares y los rangos de expresión de los diferentes marcadores celulares importantes como parte del control de calidad de rutina en los laboratorios de citometría. Conclusión. Los patrones inmunofenotípicos identificados y la determinación de los valores absolutos y relativos de referencia de las distintas poblaciones leucocitarias normales en MO podrán ser utilizados por los laboratorios de citometría como modelo para establecer parámetros de referencia en el análisis fenotípico de neoplasias hematológicas.

Objective. To describe a standardized flow cytometry protocol for the relative and absolute quantification of hematopoietic cell subpopulations from normal bone marrow, and to evaluate the expression of different lineage-specific cell markers with a reactivity associated to cell differentiation to be used as part of the routine quality control in cytometry laboratories. Materials and methods. The immunophenotypical analysis of different cell subpopulations was done with samples from normal bone marrow using a panel of monoclonal and polyclonal antibodies useful in the characterization of acute leukemias with four different fluorescences, by means of a protocol that combines cell labeling of membrane and cytoplasm antigens. Expression analysis was done in terms of mean fluorescence intensity (MFI). Fluorescent beads at a known concentration were added for calculating the absolute count of cells. Results. The antibody panel used allowed the identification and quantification of different normal leukocyte subpopulations of lymphatic and myeloid origin, including CD34+ stem cells and more differentiated cell populations in the granulocytic, monocytic, and erythroid cell lines. We established reference values for cell populations and cell marker expression ranges as part of routine quality control of cytometry laboratories. Conclusion. Immunophenotypic patterns identified as well as absolute and relative reference values for the different normal leukocyte populations from bone marrow can be used by cytometry laboratories as a basis for establishing reference parameters in phenotypic analyses of hematologic neoplasia.

Objetivo. Descrever um protocolo padronizado por citometria de fluxo para quantificar em termos absolutos e relativos diferentes subpopulações de células de medula óssea normal e analisar a expressão de diferentes marcadores celulares de linhagem específica, cuja reatividade é associada com a diferenciação celular para ser usado como parte do controle de qualidade de rotina nos laboratórios de citometria de fluxo. Materiais e métodos. A análise imunofenotípica das subpopulações de células foi realizada em amostras de MO normais utilizando um painel de anticorpos monoclonais e policlonais úteis para a caracterização fenotípica de leucemia aguda em quatro fluorescências, com um protocolo que combina rotulagem celular de antígeno de membrana celular e de citoplasma. A análise de expressão foi realizada em termos de intensidade média de fluorescência. Para calcular a recontagem absoluta foram adicionadas esferas fluorescentes de concentração conhecida. Resultados. O painel de anticorpos utilizado permitiu a identificação e quantificação das subpopulações de leucócitos normais de origem linfóide e mielóide incluindo as células precursoras CD34+, e populações de células mais diferenciadas incluídas nas linhas granulocítica, monocítica e eritróide. Foram estabelecidos os valores de referência das populações celulares e os intervalos de expressão dos diferentes marcadores celulares importantes como parte da rotina de controle de qualidade em laboratórios de citometria. Conclusão. Os padrões imunofenotípicos identificados e a determinação dos valores absolutos e relativos de referência das diferentes populações de leucócitos normais em MOM podem ser utilizados pelos laboratórios de citometria como um modelo para estabelecer parâmetros de referencia na análise fenotípica de neoplasias hematológicas.

Evaluación de características morfológicas e inmunofenotipo de células madre mesenquimales en cultivo obtenidas a partir de sangre de cordón umbilical y médula ósea / Assessment of morphologic characteristics and immunophenotype of mesenchimal stem cell culture obtained from umbilical cord blood and bone marrow

La sangre del cordón umbilical y la médula ósea humana son una alternativa para el aislamiento y cultivo de células madre mesenquimales, útiles en terapias de regeneración tisular e inmunomodulación. El objetivo de este trabajo fue aislar y cultivar células madre mesenquimales a partir de la sangre del cordón umbilical y de la médula ósea. Se recolectaron muestras de sangre de cordón umbilical en el servicio de Gineco-Obstetricia del Hospital Occidente de Kennedy en Bogotá, Colombia. La recolección de médula ósea se realizó en los servicios de ortopedia y traumatología del hospital universitario San Ignacio de Bogotá, Colombia. Se evaluó la tasa de generación celular, características morfológicas por microscopia invertida y tinción de Wright, asi como el inmunofenotipo de las poblaciones celulares por citometría de flujo. La eficiencia de aislamiento de las células madre mesenquimales a partir de sangre de cordón umbilical fue del 30/100 con una tasa de generación entre 20 y 50 minutos. A partir de médula ósea el aislamiento fue del 100/100, con un tiempo de generación entre 16 y 39 minutos. Se observaron diferencias morfológicas por tinción de Wright y la presencia de progenitores hematopoyéticos durante el cultivo primario (3.54/100 de CD34+/CD45+), que disminuían cuando se realizaba el primer pase del cultivo (0.19/100 de CD34+/CD45+). El aislamiento de células madre mesenquimales es más eficiente a partir de medula ósea. Se observan diferencias morfológicas por microscopia invertida y tinción de Wright entre células aisladas de sangre de cordón umbilical y médula ósea. El antígeno CD105 constituye un marcador importante en el establecimiento del perfil inmunofenotípico de células madre mesenquimales.

Células madre mesenquimales: características biológicas y aplicaciones clínicas / Mesenchymal stem cells: Biological characteristics and clinical applications

Las células madre mesenquimales son células pluripotentes y adultas con morfología fibroblastoide y plasticidad hacia diversos linajes celulares como condrocitos, osteocitos y adipocitos entre otros. Estas células pueden ser aisladas principalmente de médula ósea, sangre de cordón umbilical y tejido adiposo de donde se han logrado establecer cultivos que han permitido estudiar sus propiedades funcionales y fenotípicas. Aunque la información obtenida hasta la fecha no brinda un conocimiento completo, se espera que con el desarrollo de próximas investigaciones se aclaren diversos aspectos biológicos para implementar su uso en medicina regenerativa. Esta revisión presenta una visión general sobre las células madre mesenquimales: morfología e inmunofenotipo, ontogenia, fuentes de obtención y aplicaciones clínicas.