Large numbers of primitive stem cells are active simultaneously in aggregated embryo chimeric mice

The possibility has been repeatedly raised that erythropoiesis results from clonal succession--the differentiation of one or a very small number of the most primitive stem cells that are sequentially activated to proliferate forming clones of differentiated cells and then eventually decline, to be replaced by new stem cell clones. We studied this possibility in chimeric mice made by combining embryos from two different strains so that they would have two distinct stem cell populations, each of which produces a different hemoglobin type (d and s). These were compared with F1 hybrids in which every stem cell produces both types. We measured the percentage of type d in seven to ten serial samples of circulating reticulocytes taken at three- to seven-day intervals and found that the variability in percent of this hemoglobin was only slightly higher in the chimeric mice than in F1 controls; SD ranged from 2.7% to 5.5% in the chimeric mice and from 3.4% to 3.9% in the controls. Using the binomial formula, the numbers of new clones formed during the reticulocyte life span, approximately three days, ranged from 33 to 118 in the individual chimeric mice. However, these numbers are underestimates because estimated numbers of clones depend inversely on variabilities, and the calculations did not exclude the contribution of experimental error to the overall variability. Total percentages of type d hemoglobin were also measured in seven to nine successive serial samples at 60- to 136-day intervals. These gave mean values similar to measures of newly synthesized hemoglobin in the same mice, but SD were larger, ranging from 5.3% to 8.4%. This reflects experimental error, both because of excess day-to- day variability found in this type of measurement and because there could not be fewer primitive stem cells activated to form clones of erythrocytes during the 45-day erythrocyte life span than during the three-day life span of reticulocytes. Since most and maybe all of the variation between successive samples in the same chimeric mouse appear to result from experimental error, many or even all of the primitive stem cells may simultaneously contribute to erythropoiesis.

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Large numbers of primitive stem cells are active simultaneously in aggregated embryo chimeric mice

Blood ◽

10.1182/blood.v69.3.773.773 ◽

1987 ◽

Vol 69 (3) ◽

pp. 773-777 ◽

Cited By ~ 31

Author(s):

DE Harrison ◽

C Lerner ◽

PC Hoppe ◽

GA Carlson ◽

D Alling

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Life Span ◽

Experimental Error ◽

F1 Hybrids ◽

Chimeric Mouse ◽

Chimeric Mice ◽

Mean Values ◽

Type D ◽

Serial Samples

Abstract The possibility has been repeatedly raised that erythropoiesis results from clonal succession--the differentiation of one or a very small number of the most primitive stem cells that are sequentially activated to proliferate forming clones of differentiated cells and then eventually decline, to be replaced by new stem cell clones. We studied this possibility in chimeric mice made by combining embryos from two different strains so that they would have two distinct stem cell populations, each of which produces a different hemoglobin type (d and s). These were compared with F1 hybrids in which every stem cell produces both types. We measured the percentage of type d in seven to ten serial samples of circulating reticulocytes taken at three- to seven-day intervals and found that the variability in percent of this hemoglobin was only slightly higher in the chimeric mice than in F1 controls; SD ranged from 2.7% to 5.5% in the chimeric mice and from 3.4% to 3.9% in the controls. Using the binomial formula, the numbers of new clones formed during the reticulocyte life span, approximately three days, ranged from 33 to 118 in the individual chimeric mice. However, these numbers are underestimates because estimated numbers of clones depend inversely on variabilities, and the calculations did not exclude the contribution of experimental error to the overall variability. Total percentages of type d hemoglobin were also measured in seven to nine successive serial samples at 60- to 136-day intervals. These gave mean values similar to measures of newly synthesized hemoglobin in the same mice, but SD were larger, ranging from 5.3% to 8.4%. This reflects experimental error, both because of excess day-to- day variability found in this type of measurement and because there could not be fewer primitive stem cells activated to form clones of erythrocytes during the 45-day erythrocyte life span than during the three-day life span of reticulocytes. Since most and maybe all of the variation between successive samples in the same chimeric mouse appear to result from experimental error, many or even all of the primitive stem cells may simultaneously contribute to erythropoiesis.

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Identification of hematopoietic stem cell subsets on the basis of their primitiveness using antibody ER-MP12

Blood ◽

10.1182/blood.v85.4.952.bloodjournal854952 ◽

1995 ◽

Vol 85 (4) ◽

pp. 952-962 ◽

Cited By ~ 37

Author(s):

JC van der Loo ◽

WA Slieker ◽

D Kieboom ◽

RE Ploemacher

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Hematopoietic Stem Cell ◽

Antigen Expression ◽

Chimeric Mouse ◽

Hematopoietic Stem ◽

Colony Forming Units

Monoclonal antibody ER-MP12 defines a novel antigen on murine hematopoietic stem cells. The antigen is differentially expressed by different subsets in the hematopoietic stem cell compartment and enables a physical separation of primitive long-term repopulating stem cells from more mature multilineage progenitors. When used in two-color immunofluorescence with ER-MP20 (anti-Ly-6C), six subpopulations of bone marrow (BM) cells could be identified. These subsets were isolated using magnetic and fluorescence-activated cell sorting, phenotypically analyzed, and tested in vitro for cobblestone area-forming cells (CAFC) and colony-forming units in culture (CFU-C; M/G/E/Meg/Mast). In addition, they were tested in vivo for day-12 spleen colony-forming units (CFU-S-12), and for cells with long-term repopulating ability using a recently developed alpha-thalassemic chimeric mouse model. Cells with long-term repopulation ability (LTRA) and day-12 spleen colony-forming ability appeared to be exclusively present in the two subpopulations that expressed the ER-MP12 cell surface antigen at either an intermediate or high level, but lacked the expression of Ly- 6C. The ER-MP12med20- subpopulation (comprising 30% of the BM cells, including all lymphocytes) contained 90% to 95% of the LTRA cells and immature day-28 CAFC (CAFC-28), 75% of the CFU-S-12, and very low numbers of CFU-C. In contrast, the ER-MP12hi20- population (comprising 1% to 2% of the BM cells, containing no mature cells) included 80% of the early and less primitive CAFC (CAFC-5), 25% of the CFU-S-12, and only 10% of the LTRA cells and immature CAFC-28. The ER-MP12hi cells, irrespective of the ER-MP20 antigen expression, included 80% to 90% of the CFU-C (day 4 through day 14), of which 70% were ER-MP20- and 10% to 20% ER-MP20med/hi. In addition, erythroblasts, granulocytes, lymphocytes, and monocytes could almost be fully separated on the basis of ER-MP12 and ER-MP20 antigen expression. Functionally, the presence of ER-MP12 in a long-term BM culture did not affect hematopoiesis, as was measured in the CAFC assay. Our data demonstrate that the ER-MP12 antigen is intermediately expressed on the long-term repopulating hematopoietic stem cell. Its level of expression increases on maturation towards CFU-C, to disappear from mature hematopoietic cells, except from B and T lymphocytes.

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The Hypoxic Preconditioning Effect On Senescence Cell Process In Cultured Adipose-Derived Mesenchymal Stem Cells (AMSCs)

Indonesian Journal of Cardiology ◽

10.30701/ijc.v39i3.802 ◽

2019 ◽

Vol 39 (3) ◽

Author(s):

Nadiar Dwi Nuarisa ◽

I Gde Rurus Suryawan ◽

Andrianto Andrianto

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Stem Cell ◽

Life Span ◽

Hypoxic Preconditioning ◽

Differentiation Potential ◽

Hypoxic Precondition ◽

Significant Difference

Introduction : Stem cell therapy for myocardial regeneration is expected to increase cardiomyocyte proliferation and trigger neovascularization to improve cardiomyocytes. Mesenchymal Stem Cells (MSCs) are ideal candidates for regenerative medicine and immunotherapy. But low viability of MSCs is a major challenge in this alternative therapy. Therefore, a cytoprotective strategy is needed, one of them is hypoxic preconditioning which can significantly increase survival stem cells after being transplanted. MSCs are known to have a limited life span, after experiencing several splits MSC will enter the senescence process. It is known that hypoxia can also increase cell proliferation and differentiation potential in vitro and in vivo through the role of Octamer-4 (Oct-4) as a regulator of the pluripotency gene. Methods : Experimental laboratory studies (in vitro studies) using human-AMSCs which were given hypoxic preconditioning, observed as a immunocytochemistry. Results : The results showed that hypoxic precondition (1% O2) inhibited the senescence process. It can be seen in the lower expression of senescence in hypoxic conditions at P6, P7, P8, P9, P10 compared to normoxic ((p=0,004, p=0,001, p=0,009, p=0,013, p=0,024. There is a significant difference in the senescence expression of each passage in hypoxic and normoxic conditions with the highest expression at P10. In addition, we also observed AMSCs differentiation through the Oct-4 expression. It is showed that Oct-4 expression were higher in hypoxia compared to normoxia on P7, P8, P9, P10 (p=0,009, p=0,009, p=0,030, p=0,0001). Conclusions : Hypoxic preconditioning have the effect of inhibiting the senescence process on Adipose-derived MSCs (AMSCs) or prolonging their life span. The longer life span of AMSCs is also seen by higher cell differentiation potential from increased expression of Oct-4. However, the mechanism of inhibiting the senescence process in hypoxia in stem cells is still remain unknown. Keywords: human-Adipose derived Mesenchymal Stem Cell Cultures (h-AMSCs), Hypoxic Preconditioning, Senescence cell, Oct-4.

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The differentiation program of embryonic definitive hematopoietic stem cells is largely α4 integrin independent

Blood ◽

10.1182/blood-2005-10-4209 ◽

2006 ◽

Vol 108 (2) ◽

pp. 501-509 ◽

Cited By ~ 17

Author(s):

Ruby Gribi ◽

Lilian Hook ◽

Janice Ure ◽

Alexander Medvinsky

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Specific Requirement ◽

Chimeric Mice ◽

Hematopoietic Stem ◽

Adult Mice ◽

Conflicting Evidence ◽

Mutant Cells ◽

Fetal Stage

Previous analyses of the roles of α4 integrins in hematopoiesis by other groups have led to conflicting evidence. α4 integrin mutant cells developing in [α4 integrin–/–: wt] chimeric mice are not capable of completing lymphomyeloid differentiation, whereas conditional inactivation of α4 integrin in adult mice has only subtle effects. We show here that circumventing the fetal stage of hematopoietic stem cell (HSC) development by transplantation of embryonic α4 integrin–/– cells into the adult microenvironment results in robust and stable long-term generation of α4 integrin–/– lymphoid and myeloid cells, although colonization of Peyer patches and the peritoneal cavity is significantly impaired. We argue here that collectively, our data and the data from other groups suggest a specific requirement for α4 integrin during the fetal/neonatal stages of HSC development that is essential for normal execution of the lymphomyeloid differentiation program.

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High-activity samarium-153-EDTMP therapy followed by autologous peripheral blood stem cell support in unresectable osteosarcoma

Nuklearmedizin ◽

10.1055/s-0038-1625284 ◽

2001 ◽

Vol 40 (06) ◽

pp. 215-220 ◽

Cited By ~ 33

Author(s):

S. Bielack ◽

S. Flege ◽

J. Eckardt ◽

J. Sciuk ◽

H. Jürgens ◽

...

Keyword(s):

Stem Cells ◽

Stem Cell ◽

High Activity ◽

Peripheral Blood ◽

Peripheral Blood Stem Cell ◽

Blood Stem Cell ◽

High Dose ◽

External Radiotherapy ◽

Primary Tumor Site ◽

Hematopoietic Stem

Summary Purpose: Despite highly efficacious chemotherapy, patients with osteosarcomas still have a poor prognosis if adequate surgical control cannot be obtained. These patients may benefit from therapy with radiolabeled phosphonates. Patients and Methods: Six patients (three male, three female; seven to 41 years) with unresectable primary osteosarcoma (n = 3) or unresectable recurrent sites of osteosarcomas (n = 3) were treated with high-activity of Sm-153-EDTMP (150 MBq/kg BW). In all patients autologous peripheral blood stem cells had been collected before Sm-153-EDTMP therapy. Results: No immediate adverse reactions were observed in the patients. In one patient bone pain increased during the first 48 hrs after therapy. Three patients received pain relief. Autologous peripheral blood stem cell reinfusion was performed on day +12 to +27 in all patients to overcome potentially irreversible damage to the hematopoietic stem cells. In three patient external radiotherapy of the primary tumor site was performed after Sm-153-EDTMP therapy and in two of them polychemotherapy was continued. Thirty-six months later one of these patients is still free of progression. Two further patients are still alive. However, they have developed new metastases. The three patients who had no accompanying external radiotherapy, all died of disease progression five to 20 months after therapy. Conclusion: These preliminary results show that high-dose Sm-153-EDTMP therapy is feasible and warrants further evaluation of efficacy. The combination with external radiation and polychemotherapy seems to be most promising. Although osteosarcoma is believed to be relatively radioresistant, the total focal dose achieved may delay local progression or even achieve permanent local tumor control in patients with surgically inaccessible primary or relapsing tumors.

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