Growth characteristics and expansion of human umbilical cord blood and estimation of its potential for transplantation in adults.

Abstract

We estimated whether single collections of cord blood contained sufficient cells for hematopoietic engraftment of adults by evaluating numbers of cord blood and adult bone marrow myeloid progenitor cells (MPCs) as detected in vitro with steel factor (SLF) and hematopoietic colonystimulating factors (CSFs). SLF plus granulocyte-macrophage (GM)-CSF detected 8-to 11-fold more cord blood GM progenitors [colony-forming units (CFU)-GM] than cells stimulated with GM-CSF or 5637 conditioned medium (CM), growth factors previously used to estimate cord blood CFU-GM numbers. SLF plus erythropoietin (Epo) plus interleukin 3 (IL-3) enhanced detection ofcord blood multipotential (CFU-GEMM) progenitors 15-fold compared to stimulation with Epo plus IL-3. Under the same conditions, bone marrow CFU-GM and CFU-GEMM were only enhanced in detection 2-to 4-and 6-to 8-fold. Increased detection of cord blood CFU-GEMM correlated directly with decreased detection of cord blood erythroid burst-forming units (BFU-E). In contrast, adult bone marrow CFU-GEMM and BFU-E numbers were both enhanced by SLF plus Epo plus IL-3. This suggests that most cord blood BFU-E may actually be CFU-GEMM. Cord blood collections (n = 17) contained numbers of MPCs (especially CFU-GM) similar to the number found in nine autologous bone marrow collections. To assess additional sources of MPCs, the peripheral blood of 1-day-old infants was assessed. However, average concentrations of MPCs circulating in these infants were only 30-46% that in their cord blood. Expansion of cord blood MPCs was also evaluated. Incubation of cord blood cells for 7 days with SLF resulted in 7.9-, 2.2-, and 2.7-fold increases in numbers of CFU-GM, BFU-E, and CFU-GEMM compared to starting numbers; addition of a CSF with SLF resulted in even greater expansion of MPCs. The results suggest that cord blood contains a larger number ofearly profile MPCs than previously recognized and that there are probably sufficient numbers of cells in a single cord blood collection to engraft an adult. Although the expansion data must be considered with caution, as human marrow repopulating cells cannot be assessed directly, in vitro expansion of cord blood stem and progenitor cells may be feasible for clinical transplantation.Circulating blood cells are derived from hematopoietic stem and progenitor cells (1). Bone marrow is the main source of stem and progenitor cells in the adult, but, ontologically, these cells are found first in yolk sac, next in fetal liver and spleen, and subsequently in fetal bone marrow (1-3). Human umbilical cord blood is a rich source of these parent cells (reviewed in refs. 4 and 5). Our previous study (4) inferred that cord blood from single collections should contain enough stem and progenitor cells for hematopoietic reconstitution in a transplant setting, a possibility verified by successful hematopoietic engraftment of children with human leukocyte antigen (HLA)-matched sibling cord blood cells (5-7).The critical question addressed here is whether a single collection ...

Biologic and phenotypic analysis of early hematopoietic progenitor cells in umbilical cord blood

“…tor cells at similar or higher frequency than that of BM. 1,[7][8][9]12 Therefore, UCB, which is normally discarded, has been evaluated as a source of progenitor cells that can be used for the treatment of diseases potentially curable by bone marrow transplantation (BMT). [2][3][4] Major concerns for wider transplant application of UBC have been related to the low total number of progenitor cells obtained by a single collection.…”

“…Therefore, many attempts are ongoing better to understand the biologic and immunologic characteristics of UCB progenitor cells and to evaluate potential for their ex vivo expansion. [7][8][9]11 The structural and functional integrity of the hematopoietic system is maintained by a relatively small population of stem cells that undergo self-renewal. 26,27 Unfortunately, in vitro assays are not available for identifying pluripotential stem cells because of immense heterogeneity within the stem and progenitor cell compartments.…”

“…4 Therefore, many attempts are ongoing to evaluate the possibility of expanding UCB progenitor cells [7][8][9]11 and SCF in combination with other CSFs has been proven as a relevant factor for amplification of those cells capable of hematopoietic engraftment. SCF has been reported to act in combination with a variety of CSFs to influence the development of early hematopoietic progenitor cells.…”

“…[3][4][5][6] However, the major concern for future transplant application in adult patients has been related to the low number of progenitor cells that could be obtained by a single UCB collection. Several studies suggested that UCB contains a higher proportion of hematopoietic progenitor cells as compared to adult BM [7][8][9] and therefore the lower number of nucleated cells, present in a single collection, might be compensated by a higher proportion of primitive cells. Since the proliferation of hematopoietic cells is dependent on the presence of hematopoietic cytoCorrespondence: C Almici, Cattedra di Ematologia, Università di Parma, Via Gramsci 14, I-43100 Parma, Italy; Fax: 39 521 292765 Received 17 October 1996; accepted 3 September 1997 kines, 10 the ex vivo expansion potential of UCB has been examined.…”

Differential growth factor requirement of primitive cord blood hematopoietic stem cell for self-renewal and amplification vs proliferation and differentiation

“…of Biomedical Sciences and Human Oncology, Clinica Medica I, Via Genova 3, 10126 Torino, Italy; Fax: 39 11 6637 238 Received 17 November 1997; accepted 23 January 1998 are characterized by an ability to generate very large numbers (Ͼ10 13 ) of all known mature blood cell types. [1][2][3][4] In both mouse and human systems, a subset of extremely primitive hematopoietic cells has been identified because of its ability to generate clonogenic cells (colony-forming cells (CFC)) for at least 5 weeks on suitable stroma feeder layers of murine or human origin. 5 These long-term culture-initiating cells (LTCICs) share a number of features with long-term in vivo repopulating cells.…”