人胚胎干细胞在血清和无血清培养体系中的特性比较

目的 探讨血清培养体系和无血清培养体系对人胚胎干细胞（hES cells）生长特性的影响。 方法 将人胚胎干细胞株BG02接种在丝裂霉素C处理灭活的小鼠胚胎成纤维细胞饲养层上,分别在含血清hES完全培养基或无血清培养基中连续培养25~30代。在不同培养体系下比较人胚胎干细胞形态、集落贴壁率;运用BrdU掺入法检测人胚胎干细胞增殖,用细胞计数法计算细胞倍增时间;采用免疫荧光染色检测人胚胎干细胞特异性分子标志的表达;用流式细胞仪检测人胚胎干细胞Oct-4,Nanog阳性的比例;RT-PCR检测成纤维细胞生长因子(FGFs)家族基因的表达。 结果 在两种培养体系的BG02细胞都具有人胚胎干细胞的形态特征。在含血清培养体系下,BG02细胞集落贴壁率和表达OCT-4,Nanog的阳性细胞明显高于无血清培养体系( P<0.05)。无血清培养体系中,BG02细胞生长速度明显高于含血清培养体系,细胞倍增时间分别为(33.8±4.3) h、(45.9±5.7) h,( P<0.05)。无血清培养体系的BG02细胞高表达 FGF2 、 FGFR2 、 FGFR4 。 结论 两种不同培养体系中人胚胎干细胞的体外培养特性存在一定的差异,可能与BG02细胞 FGFs 家族基因激活有关。     

Comparative evaluation of cytotoxicity of cadmium in rat liver cells cultured in serum-containing medium and commercially available serum-free medium

Cadmium (Cd) is an industrial pollutant and carcinogenic metal. Most in vitro Cd toxicity studies have been carried out in various cell lines cultured in 10% fetal bovine serum (FBS) containing medium. In this report, we compared the toxic effect of Cd (0-300 microM) on cell growth, total RNA, total proteins, and antioxidant enzymes in rat normal liver cells cultured in medium with 10% FBS or commercially available serum-free medium for 4 or 8 hours. With Cd concentration at above 100 microM, the total levels of RNA, protein and cell growth decreased in serum-containing medium, while their levels increased in serum-free medium compared to the controls. The glutathione peroxidase and glutathione reductase levels were lower in serum-free medium than in serum-containing medium, indicating less oxidative stress in cells grown in serum-free medium. These results clearly suggest that Cd showed higher toxicity to liver cells grown in serum-containing medium in comparison to commercially available serum-free medium. It is speculated that albumin and other substances present in commercial serum-free medium chelated Cd and thereby protected these cells against Cd toxicity. Even under in vivo conditions, cadmium enters into various organs after passing through blood which contains serum. Based on these studies, it appears that media containing serum may be ideal for in vivo toxicity correlation studies with animal cells.     

两种不同培养体系培养人角朊细胞的特征

目的对比有饲养层的有血清培养体系(feeder layer，serum-containing medium，FSCM)和无血清培养体系(serum free medium，SFM)培养人角朊细胞(keratinocyte，KC)的特征。方法以两种不同培养体系培养人KC，比较24h细胞贴壁数、完全汇合时间和最终分化形式。结果KC在两种不同培养体系中的形态、24h细胞贴壁数和完全汇合时间无统计学差异。FSCM体系能促使角朊细胞发生终末分化；SFM体系内角朊细胞增殖较FSCM体系快，但未发生终末分化。结论有饲养层的有血清培养体系培养人角朊细胞形成复层膜片，适合临床应用；无血清培养体系培养人角朊细胞形成单层细胞，适合KC生物学性征的实验研究。     

Application of Serum-Free Culture Medium for Preparation of A-NK Cells

To compare the differences between proliferation and cytotoxicity of adherent natural killer （A-NK） cells cultured with serum-free medium AIMV and standard serum-containing medium in vitro, and also observe the assisting effect of IL-12 on the activation and the morphology character of IL-2-treated A-NK cells, cellular proliferation was evaluated by MTT method in vitro. The morphology of the target cells killed by A-NK cells was observed through electroscope. All of the A-NK cells cultured in serum-free medium AIMV could rapidly proliferate and keep high cytotoxicity compared with that in standard serum-containing medium. A-NK cells activated by both moderate-dose IL-2 and IL-12 were superior to the high-dose IL-2-treated A-NK cells. These data indicated that serum-free medium AIMV could replace standard serum-containing medium for culturing A-NK cells, and moderate-dose IL-2 and IL-12 could reduce side effects caused by high-dose IL-2. The study provided a new experimental basis for experimental and clinical preparation of A-NK cells. Cellular ＆ Molecular Immunology.     

A-NK细胞培养和活化方法的改进

目的:比较A-NK细胞在完全培养基(CM)和无血清培养基(AIMV)中体外扩增及杀伤肿瘤细胞作用,同时探讨IL-12对于A-NK/IL-2治疗的辅助作用及其杀伤的形态学观察。方法:用MTT法比较不同培养条件下的A-NK细胞体外增殖能力,并测定细胞体外杀伤肿瘤细胞的活性。通过做扫描和透射电镜,对A-NK细胞杀伤的肿瘤细胞进行形态学观察。结果:不同培养条件下的A-NK细胞均可在短期内大量扩增(P<0.05),且均有很强的杀伤肿瘤的活性(P<0.05)。被A-NK细胞杀伤的肿瘤细胞的死亡形式是溶解坏死(necrosis)和凋亡(apoptosis)。结论:AIMV可替代CM用于A-NK细胞的培养。联合应用IL-12和IL-2激活A-NK细胞优于单独使用IL-2,可减轻高剂量IL-2带来的副作用。此研究为A-NK细胞的实验室研究和将来临床应用推广奠定了新的实验基础。     

Effect of a new synthetic serum replacement on insulin and somatostatin secretion from isolated rat pancreatic islets in long-term culture

Summary Serum contains insulin degrading components. We have evaluated the insulin and somatostatin secretion from isolated rat pancreatic islets during a 2-wk culture period using three different serum-containing media, and one serum-free medium with a synthetic serum replacement. Islets incubated in serum-free medium elicited significantly higher daily insulin and somatostatin secretions than islets incubated in the serum-containing media. After a 2-wk culture period, islets from the serum-free medium secreted significantly more insulin and somatostatin than islets cultured in other media when stimulated with 25 mmol/liter glucose together with 15 mmol/liter theophylline. We conclude that the serum-free medium is superior for long-term culture of rat pancreatic islets.     

CHO细胞无血清培养研究

目的:用无血清培养基培养中华仓鼠卵巢(Chinese hamster ovary,CHO)细胞。方法:应用无血清培养基采用小方瓶培养CHO细胞,观察细胞维持时间、培养过程的形态变化。结果:应用无血清培养基培养CHO细胞可维持细胞正常生长。结论:无血清培养基可以完全取代含血清培养基用于培养CHO细胞。     

HEK 293 cell suspension culture using fibronectin-adsorbed polymer nanospheres in serum-free medium

Previously, we reported on suspension culture of anchorage-dependent animal cells using plain polymer nanospheres in serum-containing medium. For commercial cell culture, it is more advantageous to use serum-free medium than serum-containing medium. To culture anchorage-dependent animal cells using polymer nanospheres in serum-free medium, the nanospheres need to be coated with cell adhesion proteins. In this study, we utilized fibronectin-adsorbed polymer nanospheres for suspension culture of anchorage-dependent animal cells in serum-free medium. Fibronectin was adsorbed onto poly(lactic-co-glycolic acid) nanospheres (433 nm in average diameter) by immersing the nanospheres in fetal bovine serum. The nanospheres were used to culture human embryonic kidney (HEK) 293 cells in serum-free medium in stirred suspension bioreactors. Nanospheres attached between HEK 293 cells and promoted cell aggregate formation compared with culture without nanospheres. Most cells in the aggregates were viable over a 10-day culture period. Importantly, the use of poly(lactic-co-glycolic acid) nanospheres promoted the cell growth significantly, compared with culture without nanospheres (3.8- vs 1.8-fold growth). The nanosphere culture method developed in this study removes the time-consuming and costly process of adaptation of anchorage-dependent animal cells to suspension culture in serum-free medium. This culture method may be useful for the large-scale suspension culture of various types of anchorage-dependent animal cells in serum-free medium.     

Morphological and functional studies of rat hepatocytes on a hydrophobic or hydrophilic polydimethylsiloxane surface

This study describes the morphological and functional behavior of rat hepatocytes on a polydimethylsiloxane (PDMS)-coated surface. Hepatocytes were cultured on hydrophobic or hydrophilic PDMS-coated surfaces in serum-free and serum-containing media. In the serum-free medium, almost all hepatocytes adhered onto the surface irrespective of the wettability, with a cell adhesion ratio of >90% at 24h. In the serum-containing medium, although they strongly adhered onto the hydrophilic surface (cell adhesion ratio >85%), the ratio on the hydrophobic surface was <15%. Furthermore, hepatocytes in the serum-free medium gradually formed spheroids irrespective of the surface characteristics; however, on the hydrophilic surface in the serum-containing medium, they maintained a monolayer configuration for up to 10 days, and their numbers gradually decreased over time. Expression levels of the functional activities (albumin secretion and ammonia removal) and the cell-cell adhesion molecules (cadherin and connexin-32) were higher in the hepatocytes that formed spheroids compared to those which assumed a monolayer configuration, and these levels were maintained for at least 10 days. These results suggest that the wettability of PDMS and the composition of the culture medium together control the cell adhesion, morphology and expression of functional genes in hepatocytes.     

Derivation, characterization and differentiation of human embryonic stem cells: comparing serum-containing versus serum-free media and evidence of germ cell differentiation

BACKGROUND: This study was designed to establish human embryonic stem cell (hESC) lines, to identify the differences when maintained in serum-containing versus serum-free medium and to test their potential of in vitro differentiation. METHODS: Procedures including immunosurgery were performed on 11 donated human blastocysts to establish hESC lines. The cell lines were characterized and maintained using either serum-free or serum-containing media to compare their morphology, Oct-4 expression, apoptosis and growth speed. Differentiation of these lines was evaluated by the morphology and the expression of genes belonging to the three embryonic germ layers and the germ cell lineage. RESULTS: Three hESC lines were established, and they grew at similar speed in both media (serum-containing or serum-free), but hESC cultured in serum-containing medium yielded significantly higher percentages of morphologically good colonies and cells expressing Oct-4. These cell lines differentiated spontaneously in vitro into cells expressing markers belonging to all three embryonic germ layers and germ cell markers, including c-Kit, STELLA, VASA and growth differentiation factor 9 (GDF9), in directly adherent culture. CONCLUSIONS: Three hESC lines with Taiwanese ancestry have been established, and they retain the in vitro differentiation potential with or without embryoid body (EB) formation. The data support that hESC may be capable of differentiation into germ cells although further confirmation is needed. It is also suggested that strategies such as stepwise adaptation will be needed before implementing a serum-free culture condition for hESC lines that have previously been derived in a medium containing serum.     

P53在急性肾损伤小鼠肾脏的表达及其与细胞凋亡的关系

 目的：探讨缺血再灌注致急性肾损伤（AKI）小鼠肾脏不同部位P53的表达及其与细胞凋亡的关系。方法：采用随机对照动物实验方法,将18只小鼠随机分为假手术组、AKI组及P53抑制剂pifithrin-alpha（PFT-α）组,每组6只。采用双侧肾蒂夹闭45 min后松开动脉夹的方法建立小鼠AKI模型,PFT-α组于建模前5 min腹腔注射PFT-α  2.2 mg/kg,并于建模后48 h采血检测尿素氮和肌酐,取肾脏组织行HE染色观察肾组织病理学变化,采用Western blotting法测定P53蛋白含量,免疫荧光法确定肾脏不同部位P53的表达,TUNEL法检测肾脏细胞凋亡,免疫组化方法检测肿瘤坏死因子受体（TNFR）、caspase-3及Bcl-2蛋白水平 。结果：（1）PFT-α组和AKI组小鼠血尿素氮和肌酐水平均明显高于假手术组,而PFT-α组与AKI组比较血尿素氮和肌酐水平明显降低（P<0.05）;肾组织HE染色显示假手术组肾组织细胞形态完整,排列整齐,无明显病理改变,AKI组肾小管上皮细胞刷状缘脱落、空泡及滴状变性,皮髓质间有明显淤血带;PFT-α组肾小管上皮部分刷状缘脱落消失,空泡及滴状变性减轻,皮髓质间无明显淤血带;（2）假手术组小鼠肾脏有少量P53表达且未检测到凋亡细胞,而AKI组小鼠缺血再灌注48 h后P53蛋白水平及凋亡细胞明显增加（P<0.05）,并且均主要定位在肾皮质,PFT-α组较AKI组小鼠肾脏P53蛋白含量及凋亡细胞指数均减少（P<0.05）;（3）与假手术组相比,AKI组小鼠肾脏TNFR蛋白及caspase-3蛋白水平升高（P<0.05）,Bcl-2蛋白水平下降（P<0.05）,PFT-α组较AKI组小鼠肾脏TNFR蛋白及caspase-3蛋白水平降低（P<0.05）,Bcl-2蛋白水平升高（P<0.05）。结论：急性肾损伤时,肾组织P53表达增加,主要定位于皮质,通过调控凋亡蛋白Bcl-2和TNFR的水平,促进caspase-3的释放,从而介导细胞凋亡。     

Transplantation of bone marrow-derived MSCs improves cisplatinum-induced renal injury through paracrine mechanisms

Mesenchymal stem cells (MSCs) have been reported to preserve renal function in various models of acute kidney injury (AKI). Different routes were used to transplant MSCs but the role of cell transplantation routes in directing outcomes has been unknown. In the present study, we evaluated organ bio-distributions of transplanted MSCs, and correlated survival of transplanted cells with outcomes in mice with cisplatinum-induced AKI. We found that after intravenous administration, MSCs were largely localized in pulmonary capillaries and only a minute fraction of MSCs entered kidneys and the cells survived only transiently. Therefore, we also transplanted MSCs via intraperitoneal and renal subcapsular routes. Transplanted MSCs survived longer in peritoneal cavity and renal subcapsular space. Interestingly, when MSC transplantation was followed by cisplatinum-induced AKI, renal morphology and renal functions were better preserved, irrespective of the cell transplantation route. As transplanted MSCs did not migrate to kidneys from either peritoneal cavity or renal subcapsular space, this finding suggested that migration of cells was not required for the beneficial response. The possibility of indirect mechanisms was confirmed when administration of the conditioned medium from MSCs also protected renal tubular cells from cisplatinum-induced cytotoxicity. We identified presence of over forty regulatory cytokines in the conditioned medium obtained from MSCs. Since paracrine factors released by transplanted cells accounted for improvements, it appears that the route of cell transplantation is not critical for realizing benefits of cell therapy with MSCs in AKI. Studies of specific cytokines secreted by MSCs will help to obtain new therapeutic mechanisms for renal protection.     

Autologous and allogeneic marrow stromal cells are safe and effective for the treatment of acute kidney injury

Acute kidney injury (AKI) is a major clinical problem associated with high morbidity and mortality. Likely due to its complex pathophysiology, therapies with a single pharmacological agent have generally failed to improve outcomes. In contrast, stem cell-based interventions utilize these cells' ability to simultaneously target multiple pathophysiological components of AKI and thus represent a promising new tool for the treatment of AKI. The aims of the this study were to investigate the long-term outcome and safety of treatment with autologous and allogeneic mesenchymal stem cells (MSCs) after AKI and the role of vascular endothelial growth factor (VEGF) as one of the principal paracrine mediators of renoprotection of MSCs. MSC administration after AKI was not associated with adverse events and proved to be renoprotective in animals with severe renal failure. Identical doses of autologous MSC were more effective than allogeneic. At 3 months, MSCs were not engrafted in any tissues except in the bone marrow in 50% of animals given the highest allogeneic cell dose. There was no long-term fibrotic response in the kidneys attributable to MSC therapy, and animals with severe AKI were protected from development of fibrotic lesions after AKI. Furthermore, this study establishes VEGF as a critical factor mediating renal recovery. VEGF knockdown by small-interfering RNA reduced effectiveness of MSCs significantly and decreased survival. In summary, our results show that both autologous and allogeneic MSC are safe and effective in AKI, and importantly, reduce late renal fibrosis and loss of renal function in surviving animals and that VEGF is a critical factor in renoprotection by MSCs. Together, we posit that these data provide further justification for the conduct of clinical trails in which AKI is treated with MSC.     

Adenosine receptors and renal ischaemia reperfusion injury

One of the frequent clinical complications that results in billions of dollars in healthcare costs annually in the United States is acute kidney injury (AKI). Ischaemia reperfusion (IR) injury is a major cause AKI. Unfortunately, no effective treatment or preventive measure for AKI exists. With increased surgical complexity coupled with increasing number of elderly, the incidence of AKI is becoming more frequent. Adenosine is a metabolic breakdown product of adenosine triphosphate (ATP) and contributes to the regulation of multiple physiological events. Extracellular adenosine activates four subtypes of adenosine receptors (AR) including A₁AR, A_2AAR, A_2BAR and A₃AR. In the kidney, adenosine regulates glomerular filtration rate, vascular tone, renin release and is an integrative part of tubular glomerular feedback signal to the afferent arterioles. In addition, each AR subtype powerfully modulates renal IR injury. The A₁AR activation protects against ischaemic insult by reducing apoptosis, necrosis and inflammation. Activation of A_2AAR protects against renal injury by modulating leucocyte‐mediated inflammation as well as directly reducing renal tubular inflammation. Activation of A_2BAR acts via direct activation of renal parenchymal as well as renovascular receptors and is important in kidney preconditioning. Finally, activation of A₃AR exacerbates renal damage following renal IR injury while A₃AR antagonism attenuates renal damage following ischaemic insult. Latest body of research suggests that kidney AR modulation may be a promising approach to treat ischaemic AKI. This brief review focuses on the signalling pathways of adenosine in the kidney followed by the role for various AR modulations in protecting against ischaemic AKI.     

Injectable co-gels of collagen and decellularized vascular matrix improve MSC-based therapy for acute kidney injury

Transplantation of mesenchymal stem cells (MSCs) is promising for treatment of acute kidney injury (AKI), but their therapeutic effects are often limited under normal conditions. In this study, we prepared the co-gels of decellularized vascular matrix and collagen, and investigated whether the co-gels increase the therapeutic potentials of MSCs on AKI. In vitro studies indicated that the co-gels enhanced the paracrine effects of MSCs, and significantly reduced the apoptosis of MSCs under oxidative environments. When the co-gels were co-transplanted with MSCs into the kidney of model rats with ischemia-reperfusion (I/R)-induced AKI, the survival and paracrine effects of MSCs were enhanced in the injured kidney. More importantly, the co-gels increased the therapeutic effects of MSCs for AKI, as indicated by cell apoptosis, tissue damage, vascularization and renal function. Therefore, the co-gels of decellularized vascular matrix and collagen improved the therapeutic effects of MSCs, and might be promising for AKI treatment.     

Development of a serum-free medium for in vitro immune responses by using beta-cyclodextrin. Demonstration of the requirements for polyamines

A serum-free medium has been developed which is able to support primary antibody responses by cultured murine lymphocytes. This medium is based on RPMI 1640 that is supplemented with beta-cyclodextrin, insulin, transferrin, albumin, low density lipoprotein, putrescine and L-alanine as substitutes for fetal calf serum. Omission of anyone of these components resulted in a marked decrease of antibody responses. By employing the serum-free culture conditions, it was clearly demonstrated that polyamines such as putrescine, spermidine and spermine had positive effects on the development of antibody-forming cells. This serum-free medium supported the antibody response to sheep erythrocytes, trinitrophenyl (TNP)-Ficoll or TNP-lipopolysaccharide as efficiently as 10% fetal calf serum-containing medium. In addition, murine lymphocytes proliferated in response to an antigen or a mitogen equally well in these two types of medium.     

Noninvasive evaluation of renal pH homeostasis after ischemia reperfusion injury by CEST‐MRI

Acute kidney injury (AKI) in mice caused by sustained ischemia followed by reperfusion is associated with acute tubular necrosis and renal dysfunctional blood flow. Although the principal role of the kidney is the maintenance of acid–base balance, current imaging approaches are unable to assess this important parameter, and clinical biomarkers are not robust enough in evaluating the severity of kidney damage. Therefore, novel noninvasive imaging approaches are needed to assess the acid–base homeostasis in vivo. This study investigates the usefulness of MRI‐chemical exchange saturation transfer (CEST) pH imaging (through iopamidol injection) in characterizing moderate and severe AKI in mice following unilateral ischemia reperfusion injury. Moderate (20 min) and severe (40 min) ischemia were induced in Balb/C mice, which were imaged at several time points thereafter (Days 0, 1, 2, 7). A significant increase of renal pH values was observed as early as one day after the ischemia reperfusion damage for both moderate and severe ischemia. MRI‐CEST pH imaging distinguished the evolution of moderate from severe AKI. A recovery of normal renal pH values was observed for moderate AKI, whereas a persisting renal pH increase was observed for severe AKI on Day 7. Renal filtration fraction was significantly lower for clamped kidneys (0.54–0.57) in comparison to contralateral kidneys (0.84–0.86) following impairment of glomerular filtration. The severe AKI group showed a reduced filtration fraction even after 7 days (0.38 for the clamped kidneys). Notably, renal pH values were significantly correlated with the histopathological score. In conclusion, MRI‐CEST pH mapping is a valid tool for the noninvasive evaluation of both acid–base balance and renal filtration in patients with ischemia reperfusion injury.     

神经生长因子在食管鳞癌细胞中的表达及分泌

目的 探讨神经生长因子（NGF)与食管鳞癌细胞分化的相关性。方法 采用有限稀释法分选出圆形和梭形单细胞克隆,采用无血清悬浮培养获得细胞球细胞, 贴壁的Eca109细胞分别在含血清和不含血清培养基中培养48h;分别采用反转录-聚合酶链式反应（RT-PCR)技术和免疫印迹法,检测NGF在食管鳞癌细胞中mRNA水平和蛋白水平的表达;免疫荧光技术检测NGF在食管鳞癌细胞中的表达定位;免疫组织化学法检测食管鳞癌组织中NGF的表达定位;用酶联免疫吸附法（ELISA）检测NGF在Eca109细胞培养基中的分泌情况。结果 在Eca109细胞中能检测到NGF的mRNA水平和蛋白水平的表达,其中NGF在细胞球细胞中的mRNA水平和蛋白水平的表达量最高。食管癌组织中检测到NGF表达于细胞质。Eca109细胞在无血清培养条件下能够分泌NGF,且明显高于含血清培养基中的含量。结论 食管癌细胞系Eca109表达并分泌NGF,并且食管癌组织中表达NGF,NGF可能在维持食管鳞状细胞癌的干细胞特性发挥了重要作用。     

Three-dimensional co-culture of rat hepatocyte spheroids and NIH/3T3 fibroblasts enhances hepatocyte functional maintenance

Functional maintenance of primary hepatocytes in culture can be improved by several distinct approaches involving optimization of the extracellular matrix microenvironment, media composition and cell-cell interactions, both homotypic and heterotypic. Using a galactose-decorated surface, we have developed a method to combine these two approaches by co-culturing rat primary hepatocyte spheroids with NIH/3T3 mouse fibroblast cells. Spheroids were performed by culturing hepatocytes for 3 days on galactosylated poly(vinylidene difluoride) membrane; NIH/3T3 cells were subsequently seeded and co-cultured with the spheroids. Results showed that although NIH/3T3 cells alone responded poorly to the galactosylated PVDF surface and displayed limited attachment, NIH/3T3 fibroblasts attached to the periphery of the hepatocyte spheroids and proliferated around them. Co-cultured hepatocyte spheroids exhibited significantly higher liver-specific functions as compared to spheroids cultured alone. Albumin secretion level in this co-culture system peaked on day 11, which was 1.8- and 2.9-times higher than the peak expression level in spheroid homo-culture control in serum-free (day 3) and serum-containing media (day 4), respectively. The albumin secretion function was maintained for at least two weeks; it was 5.1 (in serum-free medium) and 17.8 (in serum-containing medium) times higher than spheroid homo-culture on day 13. Similarly, the co-culture system also expressed approximately 5.5- and 3.1-times higher 3-methylcholanthrene-induced cytochrome P450 enzymatic activity on day 14 as compared to the homo-culture control in serum-free and serum-containing medium, respectively. In conclusion, this unique co-culture system demonstrated the synergistic roles of homotypic cell-cell interaction, heterotypic cell-cell interaction, cell-substrate interaction and soluble stimuli in hepatocyte functional maintenance.