Haemopoietic stem cell: a new concept

Induction treatment of acute myeloid leukemia in an elderly patient with intramarrow injection/administration of cytarabine. Second case report

We show for the second time that intramarrow injection/administration of chemotherapeutic agents such as cytarabine (Ara-C) can be used safely and effectively and is associated with no toxicity, promising antileukemic activity and possible improved survival.

Induction treatment of acute myeloid leukemia in an elderly patient with intramarrow injection/administration of cytarabine: first report of a case

We have used intramarrow injection/administration of cytarabine (Ara-C) instead of conventional intravenous approach to induce remission in an elderly patient with acute myelogenous leukemia. We show for the first time that the intramarrow injection of chemotherapeutic agents such as Ara-C can be used safely and effectively.

Stem Cells and Regenerative Medicine: Myth or Reality of the 21th Century

Since the 1960s and the therapeutic use of hematopoietic stem cells of bone marrow origin, there has been an increasing interest in the study of undifferentiated progenitors that have the ability to proliferate and differentiate into various tissues. Stem cells (SC) with different potency can be isolated and characterised. Despite the promise of embryonic stem cells, in many cases, adult or even fetal stem cells provide a more interesting approach for clinical applications. It is undeniable that mesenchymal stem cells (MSC) from bone marrow, adipose tissue, or Wharton's Jelly are of potential interest for clinical applications in regenerative medicine because they are easily available without ethical problems for their uses. During the last 10 years, these multipotent cells have generated considerable interest and have particularly been shown to escape to allogeneic immune response and be capable of immunomodulatory activity. These properties may be of a great interest for regenerative medicine. Different clinical applications are under study (cardiac insufficiency, atherosclerosis, stroke, bone and cartilage deterioration, diabetes, urology, liver, ophthalmology, and organ's reconstruction). This review focuses mainly on tissue and organ regeneration using SC and in particular MSC.

Hematopoietic stromal cells and megakaryocyte development

The hematopoietic microenvironment, and in particular the hematopoietic stromal cell element, are intimately involved in megakaryocyte development. The process of megakaryocytopoiesis occurs within a complex bone marrow microenvironment where adhesive interactions, chemokines, as well as cytokines play a pivotal role. Here we review the effect of stromal cells and cytokines on megakaryocytopoiesis with the aim of exploring new therapeutic strategies for platelet recovery after hematopoietic stem cell transplantation (HSCT).

Detection of cellular receptors specific for the hepatitis B virus preS surface protein on cell lines of extrahepatic origin

Hepatitis B virus infection is primarily mediated by the interaction of the preS region of the viral envelope protein with its still unknown cellular receptor. Using recombinantly expressed preS proteins, the distribution of preS-binding receptors on cell lines from extrahepatic origins was determined by immunofluorescence and flow cytometry. In contrast to human liver cell lines, most cell lines from extrahepatic origins did not bind preS proteins. Nevertheless, exceptions were found in the bone marrow-derived cell line, KG-1, and the osteogenic sarcoma cell line SaOS-2, as well as in the previously reported EBV-transformed B-cell line, Wa. To determine the biochemical nature of these receptors, Wa-cells were cell surface biotinylated and the preS-binding receptors were isolated by immunoprecipitation. A specific band with a molecular weight of approximately 30 kDa was identified in a SDS-polyacrylamide gel, which further characterization is expected to provide clues regarding the infection mechanism of HBV in hepatic- and extra-hepatic cells.

Immunophenotypic characterization of human bone marrow endosteal cells

In order to determine the relationship between bone marrow (bm) endosteal cells (EDC) and hemopoietic progenitors, we have analyzed the immunophenotype of EDC using various antibodies (Ab) against mesenchymal antigens. The Ab were applied on paraffin sections of normal bm (iliac crest, n=17; talus, n=1; phalanx, n=1), myeloregenerative bm (after chemotherapy), and hematologic disorders (acute myeloid leukemia (AML), n=8; chronic myeloid leukemia (CML), n=6; myelodysplastic syndromes (MDS), n=14; severe aplastic anemia (SAA), n=4; essential thrombocythemia (ET), n=2; idiopathic (primary) osteomyelo-fibrosis (IMF), n=1; polycythemia vera (PV), n=1). In normal bm, EDC were found to react with Ab against vimentin, tenascin, alpha-smooth muscle actin, osteocalcin, CD51, and CD56, but did not react with Ab against CD3, CD15, CD20, CD34, CD45, CD68, or CD117. An identical phenotype of EDC was found in AML, MDS, SAA, ET, IMF, PV, myeloregenerative bm, and peripheral bones lacking active hemopoiesis (talus, phalanx). In patients with CML, EDC reacted with Ab to CD51, but did not react with Ab to CD56. Based on their unique antigen profile, EDC were enriched from normal bm by enzyme digestion and cell sorting. However, these enriched cells (CD56+, CD45-, CD34-) did not give rise to hemopoietic cells under the culture conditions used, i.e. in the presence of the growth factors IGF-1, bFGF, SCF, IL-3, and GM-CSF Together, our data do not support the hypothesis that EDC are totipotent mesenchymal progenitors giving rise to hemopoietic cells.

The origin and spread of human leukemia

The human leukemias are a group of hematologic neoplasms characterized by uncontrolled proliferation of cells concerned with blood cell production. The cause(s) of human leukemia remains unknown. Bone marrow (BM) is believed to be the site of origin of human leukemias, although the specific locus(i) and/or cell(s) from which it arises have not been definitively identified. Generally, human leukemias and related proliferative diseases are thought to be clonal in nature; affecting a single hematopoietic stem cell, which then proliferates and replaces the marrow of normal hematopoietic stem cell systems. The condition is believed to be malignant in nature. Results of our current morphologic studies on well-fixed, ideally-stained thin sections of plastic-embedded bone marrow biopsies (BMB) from a large number of acute (AML, ALL) and chronic (CGL, CLL) leukemia patients suggest that human leukemias may not be clonal diseases. Instead, a large population of other resident cells--'endosteal cells'--appears to become involved in the process and it is possible that all members of this group enter the activity simultaneously. This change (transformation) in the endosteal cell population might be due to an abnormality (qualitative or quantitative) of diffusable, humoral factors (yet to be identified) that are responsible for the growth and proliferation of these hematopoietic precursor cells. In this context, the human leukemias may be considered not as malignant, but rather the result of an aberration of factor(s) that control hematopoiesis. In this respect, the human leukemias, particularly AML, ALL and CML, might be analogous to pernicious anemia (megaloblastic anemia) as it was understood 40-50 years ago.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipogenesis in a murine bone marrow stromal cell line capable of supporting B lineage lymphocyte growth and proliferation: biochemical and molecular characterization

Recent advances in long-term bone marrow (BM) culture techniques have allowed investigators to dissect cellular components responsible for lympho hematopoiesis. Consequently, a number of "stromal" cell clones have been developed which are capable of supporting B lineage lymphocyte growth and proliferation in vitro by direct cell-cell interactions and the release of cytokines. While much work has focused on the support function of these cells, questions remain regarding their own differentiation potential. We have examined adipogenesis in the cloned BM stromal cell, BMS2. The presence of hydrocortisone, methylisobutylxanthine, or 30% fetal calf serum each accelerated adipocyte differentiation. This process was accompanied by the accumulation of triglycerides and cholesterol esters along with the induction of adipocyte-specific enzymes. Likewise, the steady-state level of mRNA transcripts increased for genes related to lipid metabolism. However, the pattern of mRNA expression in BMS2 adipocytes differed from that of a well-established, pre-adipocyte cell line, 3T3-L1, with respect to the following genes: glycerol phosphate dehydrogenase, CAAT/enhancer binding protein and angiotensinogen. Adipocyte BMS2 cells retailed the ability to support stromal cell-dependent B lineage lymphocytes in methylcellulose assays. The adipocytes continued to express macrophage-colony-stimulating factor mRNA constitutively and interleukin 6 mRNA in an inducible manner, similar to the BMS2 pre-adipocytes. Together, these data document a close developmental relationship between a specialized fibroblasts and adipocytes in the BM and suggest that adipocyte stromal cells may play an active role in lympho-hematopoiesis.

Mineralization of adult mouse bone marrow in vitro

Murine adult bone marrow exhibits mineralizing capacity in vitro as is demonstrated by the new in vitro assay we report here. In less than 2 weeks after the onset of the cultures, mineralization is obtained in more than 80% of the marrow cultures. Moreover, morphological studies reveal that during incubation phenotypic changes related to osteogenic differentiation occur at the extracellular matrix as well within cell populations. Well banded collagen is synthesized. Matrix vesicles and needles of hydroxy-apatite crystals are observed via transmission electron microscopy. Osteoblast-like cells are present with membrane-associated alkaline phosphatase activity. The mineralization is specific for cultured bone marrow and is not observed in cultured spleen fragments as is shown via 85Sr uptake, calcein uptake and histomorphology. No inducing agent is added to the tissue culture medium except for 10% fetal calf serum, beta-glycerophosphate (10(-2) M) and ascorbic acid. However, the prerequisite for obtaining mineralization is the three-dimensional structure of the marrow in culture. The in vitro organ culture we developed may provide the opportunity to identify which marrow cells have osteogenic potential and to investigate the mechanisms triggering differentiation towards osteogenesis.

Do bone marrow fat cells or their precursors have a pathogenic role in idiopathic aplastic anaemia?

Idiopathic aplastic anaemia (AA), aplastic anaemia of unknown aetiology, is usually defined as marrow failure with fatty replacement of hemopoietic tissue and peripheral pancytopenia. The pathophysiology is largely unknown, though many mechanisms have been hypothesized. These include the absence of or defects in hemopoietic stem cells (HSC), abnormalities of the bone marrow (BM) microenvironment, immune system disorders and abnormalities of the regulatory factors that control hemopoiesis. The characteristic feature of AA is the replacement of hematopoietically active marrow by fat cells; however, the fat cells themselves have received little attention to date, and this apparent fatty marrow infiltration has been considered a secondary phenomenon. That the marrow fat cells in AA may be abnormal and may have a pathogenic role has never been considered. This communication, postulates that AA may result from an abnormal and excessive proliferation of marrow fat cells and the displacement of the hematopoietic tissue of the marrow; and that the resultant marrow failure could be a secondary phenomenon.

Glycol methacrylate embedding for light microscopy. I. enzyme histochemistry on semithin sections of undecalcified marrow cores

A simple, routine procedure for water miscible glycol methacrylate (GMA) embedding of undecalcified bone marrow cores, which preserves the activity of enzymes useful in diagnosing various haematopoietic disorders, is described. The GMA used in this study has a low acid content that eliminates background staining, and the modified May-Grünwald-Giemsa stain provides good definition and excellent colour differentiation of various haematopoietic cells in the bone marrow, thereby providing optimal conditions for the study of the morphology and enzyme activity of bone marrow cells in the same preparation. The method is simple, reproducible, requires no expensive equipment, and is suitable for routine processing of small bone marrow cores in any histopathology or haematology laboratory.