Transplantation in utero of fetal human hematopoietic stem cells into mice results in hematopoietic chimerism.

Allogeneic and xenogeneic hematolymphoid chimerism has been achieved in large and small animals using varied techniques to circumvent immune mediated graft rejection by the recipient. We show here the establishment of long-term chimerism in normal mice transplanted in utero with human fetal hematopoietic stem cells (HSC). HSCs from fetal (13-20 weeks' gestation) human livers were injected into fetal mouse peritoneal cavities on days 11-13 of gestation.

Whole chromosome 17 loss in ovarian cancer.

Chromosomal deletions, associated with the loss of normal function of tumour suppressor genes, have been identified in a variety of both familial and sporadic human cancers. Although the molecular pathology of ovarian cancer is not understood, several studies have reported deletions in chromosome 17 in ovarian tumours. We have used 13 restriction site polymorphic, microsatellite, and variable number tandem repeat markers to make a detailed analysis of chromosome 17 deletions in 12 benign and 19 malignant ovarian tumours.

Adhesive interaction of hemopoietic progenitor cell membrane with the RGD domain of fibronectin.

The binding of two cloned hemopoietic progenitor cell lines, B6Sut (multipotential) and FDCP-1 (bipotential) to dishes coated with fibronectin or its chymotryptic fragments was studied by labeling the cells with 51Cr or [35S]methionine. Intact fibronectin molecule and its 120 kDa fragment, containing the Arg-Gly-Asp (RGD) sequence motif, as well as a synthetic RGD-containing peptide Peptite 2000 all bound progenitor cells. However, the 40 or 45 kDa fragments, containing the heparin-binding and CS-1 domains, failed to bind the cells in a comparable magnitude.

A novel 37-Kd adhesive membrane protein from cloned murine bone marrow stromal cells and cloned murine hematopoietic progenitor cells.

The adhesion of hematopoietic progenitor cells to bone marrow stromal cells is critical to hematopoiesis and involves multiple effector molecules. Stromal cell molecules that participate in this interaction were sought by analyzing the detergent-soluble membrane proteins of GBI/6 stromal cells that could be adsorbed by intact FDCP-1 progenitor cells. A single-chain protein from GBI/6 cells having an apparent molecular weight of 37 Kd was selectively adsorbed by FDCP-1 cells.

Suppression of normal human hematopoiesis by cytomegalovirus in vitro.

Human cytomegalovirus (HCMV) infection is associated with marrow suppression in immunocompromised patients. To examine the mechanism(s) underlying this suppression, the effect of a laboratory strain of HCMV (AD169) and a clinical isolate of HCMV on colony formation by normal human marrow (BMC) hematopoietic progenitors in the presence and/or absence of monocyte/macrophages (MO) and T cells was studied. Direct addition of HCMV at multiplicity of infection (MI) of 0.

Liver-derived fetal hematopoietic stem cells selectively and preferentially home to the fetal bone marrow.

In the course of ontogeny, the homing site for the hematopoietic stem cells (HSC) moves with certain predictability from the yolk sac to the liver/spleen and then to the marrow. The pattern of this migration has thus far been established mostly on a morphologic basis. To delineate further the course of this migration and to gain insight into its possible mechanism, we used in utero transplantation of allogeneic or xenogeneic HSC in preimmune sheep fetuses.

Ethanol enhances desialylation of transferrin by liver endothelial cells in the rat.

Desialylated transferrin is emerging as a reliable index of alcoholism, and liver endothelial cells are known to partially desialylate transferrin. The effect of a single intraperitoneal injection of ethanol on the desialylation of transferrin in the rat was studied. In pulse-chase experiments, fully sialylated diferric transferrin labeled with 125I (protein moiety) or 3H (sialyl residues) was incubated with isolated, fractionated liver endothelial cells from rats that were given ethanol.

Expression of chondroitin sulfate as a unique type of proteoglycan on the cell membrane of multipotential and committed hemopoietic progenitor cells.

Proteoglycans are increasingly implicated as a major factor in the regulation of hemopoiesis. They are generally synthesized by stromal cells and released to the extracellular matrix. More recently the ability of hemopoietic progenitor cells to synthesize proteoglycans has come into focus.

Membrane-associated chondroitin sulfate proteoglycan and fibronectin mediate the binding of hemopoietic progenitor cells to stromal cells.

The initial step in hemopoiesis is the binding of progenitor cells to stroma. What mediates this binding at the molecular level is not entirely clear. We have previously reported that the cell line FDCP-1, a factor-dependent hemopoietic progenitor cell, actively synthesizes a membrane-associated chondroitin sulfate (CS) proteoglycan (MA-PG) which is unstable.

The role of conditioning regimens in homing of transplanted hemopoietic cells.

Evidence is reviewed to indicate that the conditioning regimens given to prepare the patient for bone marrow transplantation have two unintended but desirable consequences: (a) they eliminate endogenous progenitor cells that may otherwise be in competition with grafted hemopoietic progenitor cells, leaving all homing sites open for transplanted cells, and (b) they induce membrane alterations in marrow endothelium, thus effectively removing the endothelial barrier which otherwise the grafted cells must negotiate to enter the hemopoietic compartment of the marrow. Hence the conditioning regimens may also facilitate the homing of transplanted cells.

Laboratory markers of ethanol intake and abuse: a critical appraisal.

Laboratory markers for ethanol intake and abuse and chronic alcoholism currently in use have been critically reviewed. The merits and pitfalls of each test have been evaluated. The clinical use of the new test of carbohydrate-deficient transferrin has been particularly emphasized.

Ex vivo incubation with growth factors enhances the engraftment of fetal hematopoietic cells transplanted in sheep fetuses.

Hematopoietic stem cells (HSC) transplanted in utero are in competition with endogenous HSC; thus, ultimately the graft constitutes a relatively small fraction of total HSC pool. To enhance the engraftment of donor cells in sheep fetuses, we preincubated these cells, ex vivo, for 16 hours at 37 degrees C with the conditioned medium from phytohemagglutinin-stimulated lymphocytes (PHA-LCM) before in utero transplantation. PHA-LCM is a rich source of hematopoietic growth factors in sheep.

Plasminogen activator inhibitor-1 messenger RNA expression is induced in rat hepatocytes in vivo by dexamethasone.

Plasminogen activator inhibitor-1 (PAI-1), the major physiologic inhibitor of tissue plasminogen activator (tPA), plays a crucial role in the regulation of fibrinolysis. Both hepatocytes and endothelial cells have been implicated as major sources of plasma PAI-1. To study the relative contribution of these cell types to hepatic PAI-1 production, we have separated hepatocytes and hepatic sinusoidal endothelial cells by fractionation of freshly isolated rat livers using metrizamide density gradients and centrifugal elutriation.

Engraftment and long-term expression of human fetal hemopoietic stem cells in sheep following transplantation in utero.

Hemopoietic stem cells from human fetal liver were transplanted in utero into preimmune fetal sheep (48-54 days of gestation). The fate of donor cells was followed using karyotype analysis, by immunofluorescence labeling with anti-CD antibodies, and by fluorescent in situ hybridization using human-specific DNA probes. Engraftment occurred in 13 of 33 recipients.

Effect of erythropoietic stress on donor hematopoietic cell expression in chimeric rhesus monkeys transplanted in utero.

We have previously reported the successful development of hematopoietic chimerism after the in utero transplantation of fetal hematopoietic stem cells (HSC) in rhesus monkeys (Macaca mulatta). These animals exhibit sustained engraftment without immunosuppression or graft-versus-host disease (GVHD). To assess the functional response of the donor-derived erythropoietic population, we assayed the relative expression of donor and recipient hematopoietic progenitors in chimeric monkeys before and after anemic stress.

Induction of upmodulation of homing receptors in cloned hemopoietic progenitors by growth factors.

Recognition and selective seeding of hemopoietic cells to the marrow after intravenous transplantation is a function of membrane protein known as homing receptor (HR), which is a lectin with galactosyl and mannosyl specificities. We have previously shown that ex vivo incubation of marrow cells with IL-3 or GM-CSF enhances the seeding efficiency and that this enhancement may be the result of upmodulation of homing receptors. In the present work, we have shown that incubation of two cloned progenitor cell lines, FDCP-1 and FDCP-mix, with IL-3 or GM-CSF resulted in a dose-dependent increase in the number of HR per cell.

Endothelial transcytosis of iron-transferrin in the liver does not involve endosomal traffic.

Through a process resembling receptor-mediated internalization, liver endothelium binds and internalizes iron-transferrin (Fe-Tf) complexes, transporting them from the luminal to abluminal side. Since in most systems, the path of receptor-mediated endocytosis leads to the endosomal compartment where the medium is acidified, it is expected that Fe and Tf become dissociated in this acidified medium. However, experiments with double labeling (59Fe, 125I-Tf) indicate that these remain associated.

Homing of liver-derived hemopoietic stem cells to fetal bone marrow.

Tissue distribution of HSC in fetal sheep was studied by in utero transplantation during the period when a switch in the site of hemopoiesis occurs from liver/spleen to the bone marrow. At day 50 of gestation, transplanted cells exclusively homed to the liver/spleen. By day 60, some HSC also homed to the marrow and, between days 60-80, their proportion in the marrow increased.

Alterations of bone marrow sinus endothelium induced by ionizing irradiation: implications in the homing of intravenously transplanted marrow cells.

The endothelium of bone marrow sinuses is a continuous layer which is selective in its cellular transport. It is not known how selective and massive seeding of hemopoietic progenitor cells after intravenous transplantation of marrow cells occurs. We postulate that the conditioning irradiation could disrupt the endothelial barrier, thus permitting the "homing" of progenitor cells to occur.