Flake A W, Hendrick M H, Rice H E, Tavassoli M, Zanjani E D
Department of Surgery, University of California, San Francisco.
Exp Hematol. 1995 Mar;23(3):252-7.
We have previously described a unique model of long-term, multilineage, human hematopoietic chimerism in sheep created by the in utero transplantation of human hematopoietic stem cells (HSC) into pre-immune fetal lambs. In this study, we examined the effect of chronic administration of recombinant human mast cell growth factor (rhMGF) on 1) human cell engraftment in pre-immune sheep and 2) human cell expression in human-sheep chimeras at 2-years posttransplant. rhMGF (25 micrograms/kg) or saline was administered in utero via chronic intraperitoneal (IP) catheters to three separate sets of twin fetuses on alternate days for 10 doses following transplantation of human HSC. Flow-cytometric and karyotype analyses of peripheral blood from two sets of twins at 45-days posttransplant and of peripheral blood from the remaining set of twins at birth revealed a significant increase in percentages of donor (human) progenitors and cells in rhMGF-treated lambs. rhMGF (60 micrograms/kg/day) was also administered by IP injection to two, 2 year-old, human-sheep chimeras for 18 consecutive days. Flow-cytometric analysis of peripheral blood and bone marrow revealed a six- to seven-fold increase in human cell expression. The effect on early human progenitors (i.e., colony-forming unit-mix [CFU-Mix], CFU granulocyte/macrophage [CFU-GM], and burst-forming unit-erythroid [BFU-E]) was determined by karyotype analysis of individual colonies grown under conditions favoring human cell growth. A three- to five-fold increase in human CFU-Mix and BFU-E occurred with a minimal increase in CFU-GM. This in vivo study supports in vitro data suggesting that MGF is a powerful regulator of human hematopoiesis and preferentially stimulates early hematopoietic progenitors. It also supports the potential value of the human-sheep model for the in vivo study of normal and abnormal human hematopoiesis.
我们之前描述过一种独特的模型，通过将人类造血干细胞（HSC）子宫内移植到免疫前的胎羊中，在绵羊体内建立长期、多谱系的人类造血嵌合体。在本研究中，我们检测了长期给予重组人类肥大细胞生长因子（rhMGF）对以下两方面的影响：1）免疫前绵羊体内人类细胞的植入；2）移植后2年时人类-绵羊嵌合体中人类细胞的表达。在人类HSC移植后，通过慢性腹腔内（IP）导管隔日给三组不同的双胎胎儿给予rhMGF（25微克/千克）或生理盐水，共给药10次。对移植后45天的两组双胎胎儿的外周血以及出生时另一组双胎胎儿的外周血进行流式细胞术和核型分析，结果显示，接受rhMGF治疗的羔羊中供体（人类）祖细胞和细胞的百分比显著增加。还通过IP注射给两只2岁的人类-绵羊嵌合体连续18天给予rhMGF（60微克/千克/天）。对外周血和骨髓进行流式细胞术分析，结果显示人类细胞表达增加了6至7倍。通过对在有利于人类细胞生长的条件下生长的单个集落进行核型分析，确定了对早期人类祖细胞（即混合集落形成单位[CFU-Mix]、粒细胞/巨噬细胞集落形成单位[CFU-GM]和红系爆式集落形成单位[BFU-E]）的影响。人类CFU-Mix和BFU-E增加了3至5倍，而CFU-GM仅有少量增加。这项体内研究支持了体外数据，表明MGF是人类造血的有力调节因子，优先刺激早期造血祖细胞。它还支持了人类-绵羊模型在正常和异常人类造血的体内研究中的潜在价值。
