左卡尼汀与促红细胞生成素对肾性贫血患者的疗效观察

目的观察左卡尼汀与促红细胞生成素对维持性血液透析患者肾性贫血的疗效。方法将60例维持性血液透析患者随机均分成2组,A组血液透析后皮下注射促红细胞生成素,每周100～150U/kg;待血细胞比容(Hct)上升至30%后减量。B组在A组治疗基础上加用左卡尼汀1.0g,静脉注射,每周2次,观察12周。结果 B组的血红蛋白(Hb)、血细胞比容水平显著高于A组(P<0.05)。B组于治疗后促红细胞生成素用量较治疗前明显减少,而A组促红细胞生成素用量无明显改变。结论左卡尼汀与促红细胞生成素联合治疗维持性血液透析患者贫血可提高促红细胞生成素疗效,减少其用量。     

不同保存液对血小板体外保存期间质量的影响

目的探讨不同血小板保存液对血小板体外保存期间质量的影响。方法分别应用3种保存液(血浆、Seto和A)保存浓缩血小板,在保存的第1、5、7和10天,进行血小板计数,并检测平均血小板体积(MPV)、胶原诱导的聚集反应、pH和二氧化碳分压(pCO2)、血小板活化率及葡萄糖消耗和乳酸生成。结果A保存液组血小板溶液的pH和pCO2比血浆组和Seto保存液组稳定。MPV3组比较差异较小。血浆组和Seto保存液组血小板活化率随保存时间延长而上升,而A保存液组比较稳定。血浆组和Seto保存液组血小板聚集率随保存时间延长而大幅度下降,A保存液组保持在70%左右。A保存液组葡萄糖消耗和乳酸生成幅度低于血浆组和Seto保存液组。结论A保存液在维持血小板体外保存期间质量的作用上优于血浆和Seto保存液。     

2～4期慢性肾脏病贫血临床观察

目的探讨慢性肾脏病(CKD)2～4期贫血的原因与治疗。方法观察60例CKD2～4期患者血象、骨髓象红细胞、血清铁及总铁结合力等指标。并随机分为A、B2组,2组均常规抗贫血治疗,A组加服促红素生成方。结果 CKD2～4期患者多为轻度贫血,少数无贫血或中度贫血者骨髓象红细胞增生活跃,表现为增生性贫血。血清铁含量减低而总铁结合力升高。配合抗贫血及中药治疗可明显提高血红蛋白含量。结论 CKD2～4期贫血原因之一系铁缺乏引起。治疗上应适当补充铁剂,配合其他相应措施如EPO、中草药等。     

单采血小板输注引发输血不良反应相关因素分析

目的调查输注单采血小板发生输血不良反应相关因素,为制定预防措施提供依据。方法收集广东省东莞市某医院2012年5～6月间,输注单采血小板后引发输血不良反应临床病例13例作为研究组,同时随机选择同期输注单采血小板未发生输血不良反应的临床病例16例作为对照组,根据受血者和献血者的基本信息设计调查方案。受血者基本信息包括:性别、年龄、输血史、药物史及外周血细胞变化(包括输血前后白细胞、嗜酸细胞、嗜碱细胞、单核细胞的绝对值之差以及血小板回收率和输血后血浆球蛋白含量);献血者基本信息包括:性别、年龄、献血次数、血小板输注前保存时间、血小板采集机型、循环量、献血前白细胞计数、献血过程中有无献血不良反应。对收集数据进行统计学分析。结果研究组输注单采血小板发生输血不良反应的受血者的年龄、性别、输血史、药物史、血小板回收率、输血前后白细胞、嗜酸细胞、嗜碱细胞、单核细胞的绝对值之差、输血后血浆球蛋白含量与对照组比较,差异均无统计学意义(P>0.05);研究组血小板输注前保存时间、献血者性别、年龄、献血次数、血小板采集机型、循环量、献血前白细胞计数与对照组比较,差异均无统计学意义(P>0.05)。结论输注单采血小板发生输血不良反应与受血者和献血者自身因素、受血者外周血细胞数量变化及血浆球蛋白含量无关。推测导致输注单采血小板而发生输血不良反应的主要因素为异源血浆蛋白的输入,推荐临床对已发生输血不良反应需再次输注血小板的患者应选择洗涤血小板。     

RWR通过与血小板表面整合素α_(Ⅱb)β_3受体作用对血栓形成的影响

目的探讨含RGD(Arg-Gly-Asp)序列的RWR小肽通过与血小板表面整合素αⅡbβ(3GPⅡb/Ⅲ)a结合,对血小板聚集抑制率、血栓重量、血管组织结构的影响。方法取10名无心脑血管疾病的健康志愿者的全血,分离富含血小板的血浆(platelet-rich plasma,PRP),采用血小板聚集仪检测不同剂量(6.25、12.5、25、50、100、200μmol/L)RWR对二磷酸腺苷二钠(ADPNa2)诱导的血小板聚集抑制率的影响;分别用0.3、0.6、1.2mg/kgRWR作用家兔及0.6、1.2、2.4 mg/kg RWR作用大鼠,建立兔动静脉旁路循环血栓模型和大鼠三氯化铁血栓模型,观察血栓重量的变化和血管组织结构的变化。结果随着RWR剂量增加,血小板最大聚集率降低,血小板聚集抑制率增加,RWR对血小板聚集抑制率的半数有效抑制浓度(IC50)为16.0μmol/L。随着RWR剂量的增加,血栓重量减少,血栓形成的抑制率增加,血管腔堵塞程度减弱,血管腔内孔隙增加。结论 RWR小肽通过与血小板表面整合素αⅡbβ(3GPⅡb/Ⅲ)a受体结合,抑制血小板聚集和抗血栓。     

川芎嗪对脓毒症诱导的急性肺损伤小鼠血管内皮生长因子水平变化的影响

目的研究川芎嗪(Tetramethylpyrazine,TMP)对脓毒症诱导的小鼠急性肺损伤(Acute lung injury,ALI)的保护作用以及对血管内皮生长因子(Vascular endothelial growth factor,VEGF)水平变化的影响。方法将小鼠随机分为假手术组(Sham组)、脓毒症组(Sep组)、治疗对照组(NS组)、TMP-A组和TMP-B组,Sep组、NS组、TMP-A组和TMP-B组采用盲肠结扎穿刺术(Cecal ligation and puncture,CLP)复制脓毒症相关性ALI模型,造模成功后,TMP-A组和TMP-B组分别经腹腔注射100 mg/kg和40 mg/kg TMP,Sham组和NS组经腹腔注射等量生理盐水,Sep组不作处理。分别于造模后0、12、24和48 h取材,HE染色观察小鼠肺组织病理学变化;ELISA检测小鼠血浆中VEGF含量变化;Western blot检测小鼠肺组织VEGF蛋白水平。结果 TMP组小鼠在造模后12 h时肺组织病理变化与Sep组相比有所减轻,24 h时肺泡水肿、肺出血及中性粒浸润均明显减轻,48 h时TMP作用最理想;TMP组小鼠血浆VEGF水平造模后24 h开始低于Sep组(P<0.05),48 h持续下降,已接近Sham组水平;TMP组小鼠肺组织VEGF蛋白水平在造模后24 h比Sep组明显升高,但低于Sham组(P<0.05);100 mg/kg TMP的效果优于40 mg/kg;小鼠肺组织VEGF水平与血浆VEGF水平呈负相关(P<0.05)。结论 TMP能够有效减轻脓毒症所致ALI,这一作用与降低血浆VEGF水平,恢复肺组织VEGF蛋白水平有关。     

CpG-ODN对肾小球肾炎进展的影响

目的观察CpG-ODN对肾小球肾炎进展的影响。方法将Wistar雄性大鼠随机分为N组(正常对照)、M组(模型对照)、CpG组和GpC组。N组大鼠经尾静脉注射生理盐水2.5ml/(kg·d),其余3组大鼠经尾静脉注射抗-thy1.1单克隆抗体2.5ml/(kg·d),隔日1次,共3次。注射抗-thy1.1单克隆抗体后,隔天,CpG组经尾静脉注射CpG-ODN,300μg/只,GpC组经尾静脉注射GpC-ODN,300μg/只,隔日注射,共3次。各组大鼠分别于用药前和第1针注射后1周测定尿蛋白;用药后第8周留取大鼠24h尿、血清及肾脏组织,检测24h尿蛋白定量、血清白蛋白和肾功;肾脏组织用于肾脏病理检查以及RT-PCR法检测TLR-9mRNA的表达。结果CpG组与M组和GpC组相比,血清白蛋白含量明显降低,且差异有显著意义;M组、CpG组和GpC组在给药后1周均出现尿蛋白,在给药后8周,24h尿蛋白含量明显增多;CpG组与M组相比,TLR-9mRNA在肾脏的表达水平明显增加,且差异有显著意义;GpC组与M组相比,差异无显著意义;光镜下可见CpG组肾组织病理改变明显加重。结论天然CpG-ODN可促进肾小球肾炎病情加重,TLR-9可能在其发生机理中起重要作用。     

人脐血造血干/祖细胞对裸鼠的致突变作用

目的研究人脐血造血干/祖细胞(HS/PCs-HUCB)对裸鼠的致突变作用。方法取雄性BALB/c裸鼠,随机分为5组:HS/PCs-HUCB高、中、低剂量组及阴性、阳性对照组,HS/PCs-HUCB高、中、低剂量组分别经尾静脉注射1.25×109、3.75×108和1.25×108个细胞/kg,阴性对照组经尾静脉注射含1%人血白蛋白的0.9%NaCl注射液,50ml/kg,阳性对照组经腹腔注射环磷酰胺,50mg/kg,每d给药1次。微核试验连续给药2d,末次给药24h后取骨髓细胞涂片,Giemsa染色,每组裸鼠计数12000个骨髓嗜多染红细胞(PCE)中微核细胞数;精子畸形试验连续给药5d,首次给药后第35天取附睾,精子滴片,伊红染色,每组裸鼠计数1500个精子的形态。结果HS/PCs-HUCB各剂量组裸鼠的微核率和精子畸形率与阴性对照组比较,差异均无统计学意义,各组间精子畸形类型构成比差异无统计学意义,畸形精子以无定形为主,其次为无钩、双头、双尾、双体、胖头等;而阳性对照组的微核率和精子畸形率均显著高于阴性对照组。结论HS/PCs-HUCB对裸鼠无致突变作用。     

Klotho基因高表达对糖尿病肾病大鼠肾脏的保护作用

目的观察Klotho基因高表达对糖尿病肾病(diabeticnephropathy,DN)大鼠肾脏的保护作用。方法采用RT-PCR法从健康Wistar大鼠肾脏中分段扩增Klotho基因,将两段基因连接后,亚克隆至腺病毒载体shuttle中,构建重组质粒shuttle/Klotho,与腺病毒骨架质粒共转染AD293细胞进行包装后,检测重组腺病毒的滴度。经Wistar大鼠腹腔注射链脲佐菌素(streptozotocin,STZ)复制DN模型,将DN模型大鼠随机分成DN组、Ad组和Klotho组,从糖尿病(diabetes mellitus,DM)模型建立成功后2周开始,Ad组每只经尾静脉注射3×108 PFU不含Klotho基因的腺病毒,Klotho组每只经尾静脉注射3×108 PFU含Klotho基因的重组腺病毒,DN组每只经尾静脉注射等体积生理盐水;并设对照组(即Con组,制备糖尿病模型时,经腹腔注射等量柠檬酸缓冲液,治疗时经尾静脉注射等体积生理盐水)。各组均每2周注射1次。实验期间,每天观察各组大鼠一般情况。分别于糖尿病模型建立成功后第4、8、16周,称量大鼠体重并处死,取左侧肾组织称重,计算肾脏指数(renal index,RI);显微镜下观察肾脏的病理学改变;RT-PCR法检测大鼠肾脏组织中Klotho基因mRNA的转录水平;ELISA法检测尿微量白蛋白水平,比浊法检测血尿素氮和血肌酐水平。结果酶切及测序鉴定证实克隆的Klotho基因正确。含Klotho基因的重组腺病毒的滴度为4.2×108 PFU/ml。DN、Ad和Klotho组大鼠从DM模型建立成功后第2周开始毛色逐渐无光泽,体重降低,活动能力减弱,食量、饮水量增加,粪便偏稀,精神状态差;从第6周开始,Klotho组大鼠的上述症状均有所改善。DM模型建立成功后第4、8、16周,与Con组相比,DN和Ad组大鼠的RI、尿微量白蛋白、血肌酐和血尿素氮水平均显著增加(P0.01),而Klotho组RI和尿微量白蛋白水平显著低于DN和Ad组(P0.05或P0.01),血肌酐和血尿素氮水平也下降,且第8、16周DN和Ad组大鼠血肌酐和血尿素氮水平高于第4周,而Klotho组无此现象;DN和Ad组大鼠的肾小球体积明显增大,肾小球系膜细胞增生,系膜区明显增宽,基膜增厚、基质大量堆积,部分肾小球出现硬化,肾小管上皮细胞肿胀,而Klotho组大鼠肾脏上述病变较DN和Ad组减轻;DN和Ad组大鼠肾脏组织中Klotho基因mRNA的转录水平明显减少(P0.05或P0.01),Klotho组变化不明显,但高于DN和Ad组(P0.01)。结论 Klotho基因高表达可减轻DN大鼠的肾脏损伤,对肾脏具有保护作用。     

瑞香素对急性血瘀大鼠血液流变学的影响

目的研究瑞香素对急性血瘀大鼠血液流变学的影响。方法40只大鼠随机分为CMC-Na正常对照组,急性血瘀模型组和瑞香素大、中、小剂量组,瑞香素大、中、小剂量组分别灌胃瑞香素200、100、50mg/kg;正常组及模型组灌服等量0.2%CMC-Na溶液,给药后第3天造模,检测血液流变学指标:全血低切、中切及高切粘度,红细胞压积(Hct),红细胞变形指数。结果血瘀模型组在高、中、低切变率的全血粘度较正常对照组明显升高(P<0.01),而使用瑞香素大、中剂量组的全血粘度均下降,较血瘀模型组有显著性改善(P<0.05或P<0.01);血瘀模型血浆粘度较正常对照组明显升高(P<0.01),与全血粘度类似,瑞香素大、中剂量组的血浆粘度较血瘀模型组有显著性改善(P<0.05或P<0.01);与模型组相比,血瘀模型组红细胞压积明显升高(P<0.01),除了低剂量组不能显著减低升高的红细胞压积外,高、中剂量组均可显著降低血瘀模型的红细胞压积。结论瑞香素对急性血瘀大鼠全血和血浆粘度以及红细胞压积具有明显降低作用,通过改善血液流变学指标,从而使血瘀状况有所改善。     

Erythrocyte fatty acids of term infants fed either breast milk,standard formula,or formula supplemented with long-chain polyunsaturates

The purpose of our study was to assess whether a supplement of fish oil (FO) and evening primrose oil (EPO) for formula-fed infants was capable of avoiding reductions in erythrocyte docosahexaenoic acid (DHA, 22∶6n−3) and arachidonic acid (AA, 20∶4n−6) associated with standard formula feeding. Healthy, term infants, whose mothers chose to formula feed, were randomized to either a placebo or supplemented formula for their first 30 wk of life. A reference group of beast-fed infants also was enrolled. Erythrocyte fatty acids were measured by capillary gas chromatography on day 5 and in weeks 6, 16, and 30. Supplementation of formula with 0.36% of total fatty acids as DHA resulted in erythrocyte DHA being maintained at or above breast-fed levels for the entire 30-wk study period, and breast feeding (0.21% DHA) resulted in a modest fall in erythrocyte DHA relative to baseline (day 5) values. The level of erythrocyte DHA in placebo formula-fed infants was halved by week 16. AA levels decreased in all infants in the first six weeks, but the levels in breast- and placebo formula-fed infants increased with age and returned to approximate baseline (day 5) values by 16 and 30 wk of age, respectively. Erythrocyte AA in FO+EPO-supplemented infants remained low and below breast- and placebo formula-fed levels. Our data suggest that dietary supplementation with DHA at 0.36% total fatty acids results in erythrocyte DHA levels above those found in breast-fed infants. EPO supplementation was not effective at maintaining erythrocyte AA when given with FO.     

注射用重组人B淋巴细胞刺激因子受体-抗体融合蛋白在恒河猴体内的安全性

目的评价注射用重组人B淋巴细胞刺激因子受体-抗体融合蛋白(RCT-18)在恒河猴体内的安全性。方法将恒河猴随机分为4组:低、中、高剂量RCT-18组和对照组,每组8只,低、中、高剂量RCT-18组分别经皮下注射4.6、16.1、57.5 mg/(kg.次)RCT-18,对照组经皮下注射0.7 ml/(kg.次)0.9%氯化钠注射液,每3 d上午同一时间给药1次,共给药91次。每天上午观察记录恒河猴的一般体征,每周常规监测体温1次,并在第1、2、3、13、14、15、28、29和30次给药前、给药后0.5、1、2、4和24 h增加测量动物体温次数。给药0.5、1.5、3、4.5、6、7.5、9个月(停药次日)及停药48 d(恢复期结束),分别对心电图、眼科、血液学、血液生化学、尿常规、血清抗RCT-18抗体、外周血单个核细胞(PBMC)分类计数、血清免疫球蛋白水平(IgG、IgA和IgM)等各项指标进行检查。给药3、6、9个月和恢复期结束,每组各解剖2只猴,进行脏器大体观察,计算脏器系数,并进行组织病理学观察。结果临床反应主要表现为给药后的体温升高;血液学指标出现具有一定剂量-反应关系的单核细胞(monocyte,MONO)数和网织红细胞(reticulocyte,RETIC)升高或网织红细胞平均体积(mean reticulocyte volume,MCVr)降低;3个剂量RCT-18组恒河猴的脏器重量和脏器系数与同期对照组相比,均无明显变化,且未见明显的脏器大体病变;3个剂量RCT-18组均出现无明显剂量相关但可逆的脾小结和淋巴滤泡萎缩;在整个试验期内未检测出血清中的抗RCT-18抗体;3个剂量组外周血淋巴细胞中IgD+细胞(成熟B淋巴细胞)比率均略有下降,但与对照组相比,差异无统计学意义(P>0.05);血清IgG、IgA和IgM从给药0.5～1.5个月后开始明显下降,恢复期结束时,除了中剂量的IgA水平,其他3个剂量RCT-18组的IgG、IgA和IgM水平均出现不同程度的回升。结论 RCT-18对恒河猴具有明显的但可恢复的免疫抑制作用。     

The Non-Erythropoietic EPO Analogue Cibinetide Inhibits Osteoclastogenesis In Vitro and Increases Bone Mineral Density in Mice

The two erythropoietin (EPO) receptor forms mediate different cellular responses to erythropoietin. While hematopoiesis is mediated via the homodimeric EPO receptor (EPOR), tissue protection is conferred via a heteromer composed of EPOR and CD131. In the skeletal system, EPO stimulates osteoclast precursors and induces bone loss. However, the underlying molecular mechanisms are still elusive. Here, we evaluated the role of the heteromeric complex in bone metabolism in vivo and in vitro by using Cibinetide (CIB), a non-erythropoietic EPO analogue that exclusively binds the heteromeric receptor. CIB is administered either alone or in combination with EPO. One month of CIB treatment significantly increased the cortical (~5.8%) and trabecular (~5.2%) bone mineral density in C57BL/6J WT female mice. Similarly, administration of CIB for five consecutive days to female mice that concurrently received EPO on days one and four, reduced the number of osteoclast progenitors, defined by flow cytometry as Lin⁻CD11b⁻Ly6C^hi CD115⁺, by 42.8% compared to treatment with EPO alone. In addition, CIB alone or in combination with EPO inhibited osteoclastogenesis in vitro. Our findings introduce CIB either as a stand-alone treatment, or in combination with EPO, as an appealing candidate for the treatment of the bone loss that accompanies EPO treatment.     

Safety of conjugated linoleic acid (CLA) in overweight or obese human volunteers

The main objective of the study was to investigate the safety of conjugated linoleic acid (CLA) in healthy volunteers. The effect of CLA on body composition was also investigated. The trial design was a randomized, double‐blind placebo controlled study including 60 overweight or obese volunteers (body mass index (BMI) 27.5—39.0 kg/m²). The subjects were divided into two groups receiving 3.4 g CLA or placebo (4.5 g olive oil) daily for 12 weeks. The safety was evaluated by analysis of blood parameters and by clinical examinations at baseline and week 12. Vital signs and adverse events were registered at baseline, week 6, and week 12. Bio Impedance Assessment was applied for body composition measurements. 55 subjects completed the study. Adverse events occurred in 10% of the subjects. No difference in adverse events or other safety parameters was found between the treatment groups. Small changes in the laboratory safety data were not regarded as clinically significant. Moreover, no clinically significant changes in vital signs were observed in any of the groups. In the CLA group, mean weight was reduced by 1.1 kg (paired t‐test p = 0.005), while mean BMI was reduced by 0.4 kg/m²(p = 0.007). However, the overall treatment effect of CLA on body weight and BMI was not significant. There were no differences found between the groups with regard to efficacy parameters. The results indicate that CLA in the given dose is a safe substance in healthy populations with regard to the safety parameters investigated.     

Fish Oil Supplementation Improves Neutrophil Function During Cancer Chemotherapy

Cancer chemotherapy is associated with neutropenia and impaired neutrophil function. This study aimed to investigate whether supplementation with low dose fish oil (FO), providing n-3 polyunsaturated fatty acids, in cancer patients receiving chemotherapy after surgical tumor (mainly gastrointestinal) removal is able to improve the function of blood neutrophils. Patients (n?=?38) receiving chemotherapy (5-fluorouracil and leucovorin) were randomized into two groups; one group (control) did not receive a supplement, while the other group (FO) received 2?g FO/day for 8?weeks; the FO provided 0.3?g eicosapentaenoic acid plus 0.4?g docosahexaenoic acid per day. Patients in the control group lost an average of 2.5?kg of weight over the 8?weeks of the study. The number of blood polymorphonuclear cells (PMNC), mainly neutrophils, and their functions (phagocytosis and hydrogen peroxide production) decreased in the control group (average decreases of approximately 30, 45 and 17%, respectively). FO prevented these decreases and actually increased body weight (average of 1.7?kg weight gain; p?相似文献   

融合蛋白IFNα2a-α-MSH对小鼠黑色素瘤生长的抑制作用

目的观察融合蛋白IFNα2a-α-MSH对小鼠移植黑色素瘤生长的抑制作用。方法将小鼠黑色素瘤细胞株B16接种于C57BL/6小鼠背部皮下,待肿瘤直径长至4mm以上时,将小鼠分为4组,分别经肌肉注射生理盐水(阴性对照)、IFNα2a(9×106U/kg鼠重)、IFNα2a-α-MSH(9×106U/kg鼠重)及腹腔注射环磷酰胺(20mg/kg鼠重,阳性对照),前3组1次/d,阳性对照组隔日1次,共11d。隔日测量肿瘤大小;末次给药后24h,处死小鼠,称瘤重,并计算肿瘤抑制率。结果 IFNα2a-α-MSH可明显抑制小鼠黑色素瘤的生长,且其抑瘤作用明显强于IFNα2a。结论 IFNα2a-α-MSH对小鼠黑色素瘤生长有较强的抑制作用,为IFNα2a-α-MSH临床治疗黑色素瘤提供了实验依据。     

抗CD20人源化单克隆抗体的急性毒性评价

目的评价抗CD20人源化单克隆抗体SM09的急性毒性。方法将食蟹猴随机分为阴性对照组、SM09 10、30和100 mg/kg剂量组,采用注射泵前臂静脉缓慢注射单次给药,阴性对照组给予等体积的生理盐水,于给药前和给药后不同时间进行各项毒理学指标检测。结果食蟹猴注射SM09,在给药速度达600 mg/h时,动物未见明显异常反应;给药后各剂量组动物临床症状、体重、进食量、体温、心电图、血压、血清生化指标均未见明显异常;血液学检测结果显示,100 mg/kg剂量组动物白细胞数量出现一过性降低;给药后第2天,各剂量组动物外周血CD20+B淋巴细胞数量即明显降低,B细胞表现出耗竭状态,给药后3～8周,B细胞水平逐渐回复,且呈剂量相关性。给药后8周剖检,100 mg/kg剂量组雌性动物脾脏呈暗红色且体积增大,镜检可见红髓扩张充血和脾小体数量减少。结论食蟹猴单次静脉注射抗CD20单抗,具有良好的耐受性,除与药理作用相关的外周血B细胞清除效应外,未见其他毒性反应,最大耐受剂量可达100 mg/kg。     

Multi-scale Modelling of Erythropoiesis and Hemoglobin Production

The paper is devoted to multi-scale modelling of erythropoiesis and hemoglobin production. Red blood cells, which carry oxygen from the lungs to the other body tissues, are produced in the bone marrow of adult humans in cell units called erythroblastic islands. Erythroblastic islands are composed by a central macrophage surrounded by erythroid cells in different stages of maturation. Immature cells, the colony-forming units-erythroid, make a choice between self-renewal, differentiation and apoptosis determined by the intracellular proteins and extracellular substances. Moreover, this choice is regulated by erythropoietin and other hormones. Erythropoietin is produced in the kidney in response to hypoxia from decreased numbers of red blood cells, and it is delivered in the plasma to the bone marrow. Erythropoietin stimulates differentiation of erythroid cells and increases their proliferation by downregulating apoptosis. The rate of erythropoietin production depends on the level of hemoglobin in blood which is function of the number of circulating red blood cells. Hemoglobin is produced in the erythroid cells within the bone marrow in the process of their terminal differentiation. Thus, there is a feedback between production of red blood cells by the bone marrow, the level of hemoglobin contained in these cells and the level of erythropoietin. The multi-scale model developed in this work includes erythroid cells in the bone marrow, their intracellular and extracellular regulations, hemoglobin production, and the feedback by erythropoietin. This model describes normal functioning of erythropoiesis and its response to anemia resulting from the loss of red blood cells.