Isolation of Kupffer cells and their suppressive effects on T lymphocyte growth in rat orthotopic liver transplantation

AIM: To develop a practical method for isolation, purifi cation and culture of hepatic Kupffer cells (KCs) and to observe their suppressive effects on the proliferation of alloreactive T cells. METHODS: Perfusion in situ in vivo combined with density gradient centrifugation was applied in isolation, purifi cation and culture of hepatic KC. The suppression by KCs on the T cell proliferation in mixed lymphocyte reaction (MLR) was observed. RESULTS: This method resulted in a satisfactorily high yield of (1.1 ± 0.2) × 107 KCs per liver, (93.5/ ± 1.8/) viable cells, over 90/ purity and positive for ED-2. After the first 24 h in culture, a great number of KCs which exhibited typical characteristics were observed. Using 3H-TdR incorporation assay, non-irradiated KCs significantly suppressed allo-MLR. The KCs recovered from accepted liver allografts in groups D and E were more effective in suppressing allo-MLR. CONCLUSION: A standardized procedure for isolation of highly purified rat KCs is proposed and KCs have suppressive effects on the proliferation of alloreactive T cells, especially those derived from accepted liver allografts.

Influence of Kupffer cells and platelets on ischemia-reperfusion injury in mild steatotic liver

AIM: To investigate the effect of mild steatotic liver on ischemia-reperfusion injury by focusing on Kupffer cells (KCs) and platelets. METHODS: Wistar rats were divided into a normal liver group (N group) and a mild steatotic liver group (S group) induced by feeding a choline-deficient diet for 2 wk. Both groups were subjected to 20 min of warm ischemia followed by 120 min of reperfusion. The number of labeled KCs and platelets in sinusoids and the blood perfusion in sinusoids were observed by intravital microscopy (IVM), which was performed at 30, 60 and 120 min after reperfusion. To evaluate serum alanine aminotransferase as a marker of liver deterioration, blood samples were taken at the same time as IVM.RESULTS: In the S group, the number of platelets adhering to KCs decreased significantly compared with the N group (120 after reperfusion; 2.9±1.1 cells/acinus vs 4.8±1.2 cells/acinus, P<0.01). The number of KCs in sinusoids was significantly less in the S group than in the N group throughout the observation periods (before ischemia, 19.6±3.3 cells/acinus vs 28.2±4.1 cells/acinus, P<0.01 and 120 min after reperfusion, 29.0±4.3 cells/acinus vs 40.2±3.3 cells/acinus, P<0.01). The blood perfusion of sinusoids 120 min after reperfusion was maintained in the S group more than in the N group. Furthermore, elevation of serum alanine aminotransferase was lower in the S group than in the N group 120 min after reperfusion (99.7±19.8 IU/L vs 166.3±61.1 IU/L, P=0.041), and histological impairment of hepatocyte structure was prevented in the S group. CONCLUSION: Ischemia-reperfusion injury in mild steatotic liver was attenuated compared with normal liver due to the decreased number of KCs and the reduction of the KC-platelet interaction.

Augmenter of liver regeneration promotes hepatocyte proliferation induced by Kupffer cells

瞄准：为了在 Kupffer 房间上观察肝新生(ALR ) 的 augmenter 的效果并且决定 ALR 是否支持 hepatocyte，增长由 Kupffer 房间导致了。方法：Kupffer 房间和 hepatocytes 是有教养的在试管内， recombinant 老鼠 ALR (rrALR ) 的各种各样的集中被增加。3H-thymidine， BrdU 和 3H 白氨酸加入在有教养的 Kupffer 房间和 hepatocytes 是坚定的，在 Kupffer 房间调节的 hepatocytes，并且在联系媒介。rrALR 被 iodination 标记并且过去常在 Kupffer 由 Scatchard 分析决定它的有约束力的活动房间和首先有教养的老鼠 hepatocytes。结果：rrALR 以一种 non-concentration-dependent 方式在房间并且在媒介在 Kupffer 房间和蛋白质合成刺激了 DNA 复制。效果在 1 microg/L ALR 的集中是重要的。然而，当 hepatocytes 是有教养的， Kupffer 房间媒介在在 1 microg/L ALR 的集中显著地增加的 hepatocytes 由 ALR， DNA 复制和蛋白质合成调节了时， rrALR 没在首先有教养的 hepatocytes 上有效果。当 ALR 集中被增加时，它 hepatocyte 增长上的效果减少了到基础水平。Scatchard 分析在老鼠 Kupffer 房间与 0.883 nmol/L 的一个离解常数(Kd ) 和 126.1 pmol/g 蛋白质的一个最大的有约束力的能力(Bmax ) 显示了高亲密关系受体的一个单个班的存在。结论：ALR 能支持 Kupffer 房间导致的 hepatocyte 增长，它与 ALR 的集中被联系，建议 Kupffer 房间起在肝新生的一个双作用。

Role of Kupffer cells in the pathogenesis of liver disease

Kupffer cells, the resident liver macrophages have long been considered as mostly scavenger cells responsible for removing particulate material from the portal circu- lation. However, evidence derived mostly from animal models, indicates that Kupffer cells may be implicated in the pathogenesis of various liver diseases including viral hepatitis, steatohepatitis, alcoholic liver disease, in- trahepatic cholostasis, activation or rejection of the liver during liver transplantation and liver fibrosis. There is accumulating evidence, reviewed in this paper, suggest- ing that Kupffer cells may act both as effector cells in the destruction of hepatocytes by producing harmful soluble mediators as well as antigen presenting cells during viral infections of the liver. Moreover they may represent a significant source of chemoattractant molecules for cy- totoxic CD8 and regulatory T cells. Their role in fibrosis is well established as they are one of the main sources of TGFβ1 production, which leads to the transformation of stellate cells into myofibroblasts. Whether all these variable functions in the liver are mediated by different Kupffer cell subpopulations remains to be evaluated. In this review we propose a model that demonstrates the role of Kupffer cells in the pathogenesis of liver disease.

Effect of Kupffer cells on immune tolerance in liver transplantation

Objective:To observe the effect of Kupfler cells on immune tolerance in liver transplantation. Methods:The rats were randomly divided into A,B and C groups.A group was sham operation group.The donor rats of group B had intraperitoneal injection of 1 nmol Kuppffer cells every other day for three days before liver transplantation.Rats of group C were injected with equal saline.The rat liver transplantation models were established by modified Kamada’s two-cuff technique.The rats were sacrificed after 24 hours.The concentrations of ALT and AST in serum were measured with the biochemical analyzer.The level of IL-2 and TNF- a in serum were measured by ELISA method.The apoptotic indexes were detected by immunohistochemical assay. Results:The concentration of ALT,AST,IL-1 and TNF- a in A,B and C groups were increased successively.The levels of group C were significantly higher than that of group B and A(P【0.05), and the levels of group B were significantly higher than that of group A(P【0.05).The apoptotic indexes of three groups were 3.40±0.37,14.70±2.54 and 26.33±3.65,respectively,with significant difference among three groups(P【0.05).Conclusions:Pretreatment with Kupfler cells can reduce liver injury and raise liver transplantation immune tolerance.

Expression of macrophage inflammatory protein-1αin Kupffer cells following liver ischemia or reperfusion injury in rats

瞄准：探索巨噬细胞的表示在在老鼠跟随肝 ischemia/reperfusion 损害 IRI 的 Kupffer 房间(KC ) 的煽动性的 protein-1alpha (MIP-1alpha ) 。方法：四十只男 SD 老鼠随机被划分成五个组。在老鼠肝的部分温暖的 ischemia/reperfusion 损害的一个模型被建立。KC 在灌注以后被孤立并且孵化一个小时，六个小时， 12 h，和 24 h。肿瘤坏死因素高山哈(TNF-alpha ) 并且在上层清液的 interleukin-1beta (IL-1beta ) 被 ELISA 测量。在 KC 的 MIP-1alpha 被细胞化学的免疫和 RT-PCR 检测。结果：没有或很少 MIP-1alpha 蛋白质和 mRNA 在控制组的 KC 被表示。它在 IRI 组的表达式在灌注以后有重要增加(P 【 0.05 ) ，它与控制组相反。结论：在 KC 后面的肝 ischemia/reperfusion 损害的 MIP-1alpha 基因的活跃行为被假定是为肝的 ischemia/reperfusion 损害的主要原因之一。

Donor denervation and elimination of Kupffer cells affect expression of P-selectin and ICAM-1 in liver graft

BACKGROUND: The non-function and dysfunction of primary liver graft likely involves dependence on Kupffer cells and hepatic innervation. The present experiment was designed to study the expression of P-selectin and intercellular adhesion molecule-1 (ICAM-1) mRNA in liver graft and to elucidate the role of Kupffer cells and the sympathetic nerve of the liver in down-regulating this expression. METHODS: Donor rats were given hexamethonium, a sympathetic ganglionic blocking agent, and/or gadolinium chloride, an inhibitor of Kupffer cells. Then the changes of graft P-selectin and ICAM-1 mRNA expression were measured after liver transplantation. RESULTS: The expressions of P-selectin and ICAM-1 mRNA were increased after liver transplantation, and down-regulated by liver denervation and elimination of Kupffer cells. CONCLUSIONS: Live donor denervation and elimination of Kupffer cells down-regulated the expressions of P-selectin and ICAM-1 mRNA in grafts. This may decrease graft ischemia/reperfusion injury.

Effects of Kupffer cell inactivation on graft survival and liver regeneration after partial liver transplantation in rats

BACKGROUND： Gadolinium chloride（Gd Cl3） selectively inactivates Kupffer cells and protects against ischemia/reperfusion and endotoxin injury. However, the effect of Kupffer cell inactivation on liver regeneration after partial liver transplantation（PLTx） is not clear. This study was to investigate the role of Gd Cl3 pretreatment in graft function after PLTx, and to explore the potential mechanism involved in this process.METHODS： PLTx（30% partial liver transplantation） was performed using Kamada’s cuff technique, without hepatic artery reconstruction. Rats were randomly divided into the control low-dose（5 mg/kg） and high-dose（10 mg/kg） Gd Cl3 groups. Liver injury was determined by the plasma levels of alanine aminotransferase and aspartate aminotransferase, liver regeneration by PCNA staining and Brd U uptake, apoptosis by TUNEL assay. IL-6 and p-STAT3 levels were measured by ELISA and Western blotting.RESULTS： Gd Cl3 depleted Kupffer cells and decreased animal survival rates, but did not significantly affect alanine aminotransferase and aspartate aminotransferase（P〉0.05）. Gd Cl3 pretreatment induced apoptosis and inhibited IL-6 overexpression and STAT3 phosphorylation after PLTx in graft tissues.CONCLUSION： Kupffer cells may contribute to the liver regeneration after PLTx through inhibition of apoptosis and activation of the IL-6/p-STAT3 signal pathway.

Heme oxygenase-1 protects donor livers from ischemia/reperfusion injury:The role of Kupffer cells

AIM:To examine whether heme oxygenase (HO)-1 overexpression would exert direct or indirect effects on Kupffer cells activation, which lead to aggravation of reperfusion injury.METHODS: Donors were pretreated with cobalt protoporphyrin (CoPP) or zinc protoporphyrin (ZnPP), HO-1 inducer and antagonist, respectively. Livers were stored at 4℃ for 24 h before transplantation. Kupffer cells were isolated and cultured for 6 h after liver reperfusion.RESULTS: Postoperatively, serum transaminases were significantly lower and associated with less liver injury when donors were pretreated with CoPP, as compared with the ZnPP group. Production of the cytokines tumor necrosis factor-α and interleukin-6 generated by Kupffer cells decreased in the CoPP group. The CD14 expression levels (RT-PCR/Western blots) of Kupffer cells from CoPP-pretreated liver grafts reduced.CONCLUSION: The study suggests that the potential utility of HO-1 overexpression in preventing ischemia/reperfusion injury results from inhibition of Kupffer cells activation.

M2-like Kupffer cells in fibrotic liver may protect against acute insult

AIM To investigate the mechanism of hepatoprotection conferred by liver fibrosis through evaluating the activation phenotype of kupffer cells.METHODS Control and fibrotic mice were challenged with a lethal dose of D-Gal N/lipopolysaccharide(LPS),and hepatic damage was assessed by histology,serum alanine transferase(ALT)levels,and hepatic expression of HMGB1,a potent pro-inflammatory mediator.The localization of F4/80(a surrogate marker of KCs),HMGB1,and type I collagen(Col-1)was determined by immunofluorescence staining.The phenotype of KCs was characterized by real-time PCR.KCs isolated from control or fibrotic mice were challenged with LPS or HMGB1 peptide,and HMGB1 translocation was analyzed.RESULTS Liver fibrosis protected mice against D-Gal N/LPS challenge,as shown by improved hepatic histology and reduced elevation of ALT compared with the normal mice treated in the same way.This hepatoprotection was also accompanied by inhibition of HMGB1 expression in the liver.Co-localization of F4/80,HMGB1,and Col-1 was found in fibrotic livers,indicating the close relationship between KCs,HMGB1 and liver fibrosis.KCs isolated from fibrotic mice predominantly exhibited an M2-like phenotype.In vitro experiments showed that HMGB1 was localized in the nucleus of the majority of M2-like KCs and that the translocation of HMGB1 was inhibited following stimulation with LPS or HMGB1 peptide,while both LPS and HMGB1 peptide elicited translocation of intranuclear HMGB1 in KCs isolated from the control mice.CONCLUSION M2-like Kupffer cells in fibrotic liver may exert a protective effect against acute insult by inhibiting the translocation of HMGB1.

Prokineticin 2/Bv8 is expressed in Kupffer cells in liver and is down regulated in human hepatocellular carcinoma

AIM: To study the implication of prokineticin 1 (PK1/EG- VEGF) and prokineticin 2 (PK2/Bv8) in hepatocellular carcinoma angiogenesis. METHODS: The gene induction of PK1/EG-VEGF and PK2/Bv8 was investigated in 10 normal, 28 fibrotic and 28 tumoral livers by using real time PCR. Their expression was compared to the expression of VEGF (an angiogenesis marker), vWF (an endothelial cell marker) and to CD68 (a monocyte/macrophage marker). Furthermore, the mRNA levels of PK1/EG-VEGF, PK2/Bv8, prokineticin receptor 1 and 2 were evaluated by real time PCR in isolated liver cell populations. Finally, PK2/Bv8 protein was detected in normal liver paraffin sections and in isolated liver cells by immunohistochemistry and immunocytochemistry. RESULTS: PK2/Bv8 mRNA but not PK1/EG-VEGF was expressed in all types of normal liver samples examined. In the context of liver tumor development, we reported that PK2/Bv8 correlates only with CD68 and showed a significant decrease in expression as the pathology evolves towards cancer. Whereas, VEGF and vWF mRNA were significantly upregulated in both fibrosis and HCC,as expected. In addition, out of all isolated liver cells examined, only Kupffer cells (liver resident macrophages) express significant levels of PK2/Bv8 and its receptors, prokineticin receptor 1 and 2. CONCLUSION: In normal liver PK2/Bv8 and its receptors were specifically expressed by Kupffer cells. PK2/Bv8 expression decreased as the liver evolves towards cancer and did not correlate with HCC angiogenesis.

Chlamydia pneumoniae replicates in Kupffer cells in mouse model of liver infection

AIM: To develop an animal model of liver infection with Chlamydia pneumoniae (C. pneumoniae) in intraperito-neally infected mice for studying the presence of chlamy-diae in Kupffer cells and hepatocytes.METHODS: A total of 80 BALB/c mice were inoculated intraperitoneally with C. pneumoniae and sacrificed at various time points after infection. Chlamydiae were looked for in liver homogenates as well as in Kupffer cells and hepatocytes separated by liver perfusion with collagenase. C. pneumoniae was detected by both isola-tion in LLC-MK2 cells and fluorescence in situ hybridiza-tion (FISH). The releasing of TNFA-α by C. pneumoniae in vitro stimulated Kupffer cells was studied by enzyme-linked immunosorbent assay.RESULTS: C. pneumoniae isolation from liver homoge-nates reached a plateau on d 7 after infection when 6 of 10 animals were positive, then decreased, and became negative by d 20. C. pneumoniae isolation from sepa-rated Kupffer cells reached a plateau on d 7 when 5 of 10 animals were positive, and became negative by d 20. The detection of C. pneumoniae in separated Kupffer cells by FISH, confirmed the results obtained by culture. Isolated hepatocytes were always negative. Stimula-tion of Kupffer cells by alive C. pneumoniae elicited high TNF-α levels. CONCLUSION: A productive infection by C. pneumo-niae may take place in Kupffer cells and C. pneumoniae induces a local pro-inflammatory activity. C. pneumoniae is therefore, able to act as antigenic stimulus when local-ized in the liver. One could speculate that C. pneumoniaeinfection, involving cells of the innate immunity such as Kupffer cells, could also trigger pathological immune re-actions involving the liver, as observed in human patients with primary biliary cirrhosis.

Role of liver X receptors alpha agonist on expressions of LPS-induced inflammatory response associated factor IRAK-4 and NF-kappaB in Kupffer cells

在 interleukin-1 受体的表情上探索激活的肝 X 受体(LXR ) 的角色的目的在在 Kupffer 房间并且到由 LPS 导致了的煽动性的反应联系了 kinase-4 (IRAK-4 ) 和 NF-kappaB (NF-B ) 调查煽动性的反应的 LXR 否定规定的可能的机制。Kupffer 房间被骨胶原灌注在 situ 从男 Kunming 老鼠孤立的方法。并且这些房间被划分成 4 个组：正常控制组， LPS 处理组， LXR 收缩筋 T0901317 处理组， LPS 和 T0901317 联合了处理组。 LPS 处理组在 RPMI 1640 与 1 g/ml LPS 的最后的集中被对待并且为 6 h 有教养， T0901317 处理组在 RPMI 1640 与 5 g/ml 的最后的集中被对待并且为 24 h 有教养，并且联合处理组在 RPMI 1640 与 1 g/ml T0901317 的最后的集中为 24 h 收到了文化前然后为有在 RPMI 1640 的 5 g/ml LPS 的最后的集中的 6 h 有教养。所有组为 30 h 是有教养的。在 mRNA 和蛋白质层次的 LXR， IRAK-4 和 NF-B 的表示被即时 PCR 并且西方的弄污检测，并且 TNF-1 和 IL-1 层次被 ELISA 检测。LXR mRNA 和蛋白质的层次是的结果在 LPS 组在 T0901317 组最高、最低(P < 0.05 ) 。IRAK4 和 NF-B mRNAs 和蛋白质的水平比在 LPS 组在联合对待的组是显然更低的(P < 0.05 ) 。并且 TNF-1 和 IL-1 的水平在 LPS 组最高被观察(P < 0.05 ) ，但是在控制组， T0901317 组和联合对待的组之中的没有差别(P > 0.05 ) 。这些标明日期的结论建议 LXR 收缩筋有效地装起来调整 LXR mRNA 和蛋白质的表情并且禁止煽动性的反应。这可能经由下面调整在 mRNA 和蛋白质层次的 IRAK4 和 NF-B 的表情。

A NEW METHOD OF ISOLATING KUPFFER CELLS FROM BIOPSY TISSUE OF RAT LIVER

The isolation of a high yield and purity of Kupffer cells has been reported in detail.1 This paper reports into the research about isolation Kupffer cells from biopsy tissue of liver. This method includes 5 important steps: (1) take fresh liver tissue, and mince with scissors. (2) spin at low speed to wash off red blood cells. (3) digest in collagenase for suitable time. (4) isolate Kupffer cells on a percoll density gradient. (5) cell charaterization was observed by N.S.E stain and peroxidatic activity with lumino-meter measurement and phagocytosis with latex beads.2.3

Roles of liver innate immune cells in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) has become the most common liver disease in the United States and other developed countries and is expected to increase in the next few years. Emerging data suggest that some patients with NAFLD may progress to nonalcoholic steatohepatitis (NASH), cirrhosis and even hepatocellular carcinoma. NAFLD can also promote the development and progression of disease in other organ systems, such as the cardiovascular and endocrine (i.e. diabetes) systems. Thus, understanding the pathogenesis of NAFLD is of great clinical importance and is critical for the prevention and treatment of the disease. Although the "two-hit hypothesis" is generally accepted, the exact pathogenesis of NAFLD has not been clearly established. The liver is an important innate immune organ with large numbers of innate immune cells, including Kupffer cells (KCs), natural killer T (NKT) cells and natural killer (NK) cells. Recent data show that an imbalance in liver cytokines may be implicated in the development of fatty liver disease. For example, Th1 cytokine excess may be a common pathogenic mechanism for hepatic insulin resistance and NASH. Innate immune cells in the liver play important roles in the excessive production of hepatic Th1 cytokines in NAFLD. In addition, liver innate immune cells participate in the pathogenesis of NAFLD in other ways. For example, activated KCs can generate reactive oxygen species, which induce liver injury. This review will focus primarily on the possible effect and mechanism of KCs, NKT cells and NK cells in the development of NAFLD.

Hepatic non-parenchymal cells and extracellular matrix participate in oval cell-mediated liver regeneration

AIM: To elucidate the interaction between nonparenchymal cells, extracellular matrix and oval cells during the restituting process of liver injury induced by partial hepatectomy (PH). METHODS: We examined the localization of oval cells, non-parenchymal cells, and the extracellular matrix components using immunohistochemical and double immunofluorescent analysis during the proliferation and differentiation of oval cells in N-2acetylaminofluorene (2-AAF)/PH rat model. RESULTS: By day 2 after PH, small oval cells began to proliferate around the portal area. Most of stellate cells and laminin were present along the hepatic sinusoids in the periportal area. Kupffer cells and fibronectin markedly increased in the whole hepatic lobule. From day 4 to 9, oval cells spread further into hepatic parenchyma, closely associated with stellate cells, fibronectin and laminin. Kupffer cells admixed with oval cells by day 6 and then decreased in the periportal zone. From day 12 to 15, most of hepatic stellate cells (HSCs), laminin and fibronectin located around the small hepatocyte nodus, and minority of them appeared in the nodus. Kupffer cells were mainly limited in the pericentral sinusoids. After day 18, the normal liver lobule structures began to recover.CONCLUSION: Local hepatic microenvironment may participate in the oval cell-mediated liver regeneration through the cell-cell and cell-matrix interactions.

Protection against hepatic ischemia/reperfusion injury via downregulation of toll-like receptor 2 expression by inhibition of Kupffer cell function

瞄准：阐明由 Kupffer 房间(KC ) 的抑制的肝保护的机制工作。方法：所有动物随机被划分成三个组。封锁组(加 ischemia/reperfusion (I/R ) 的金轧氯化物答案(GdCl3 ) 注射损害) ：GdCl3 答案被注射一次为经由在 I/R 损害前的尾巴静脉的 2 d 的每 24 h。非封锁组(加 I/R 损害的盐溶液注射) ：而不是控制作为在封锁组被注射的 GdCl3 盐。假冒的组：没有 I/R 损害， saline 被注射。肝样品被收集在血流入恢复以后的 4 h。KC 的功能的封锁被与 anti-CD68 mAb 染色的免疫验证。像使用费的受体(TLR2 ) 2 是与山羊反老鼠 polyclonal anti-TLR2 抗体染色的免疫。膜蛋白质从肝样品被提取， TLR2 蛋白质被西方的污点分析。门静脉浆液和血浆被拿同时分别地为肿瘤坏死 factor-alpha (TNF-alpha ) 和丙氨酸 aminotransferase (中高音) 的层次的进一步的察觉指，肝的指示物工作。结果：比作非封锁组，显著地在封锁组减少的 CD68+ 房间(OPTDI，光密度积分) ：32.97+/-10.55 对 185.65+/-21.88， P【0.01 ) 并且肝功能缺陷部分被减轻(中高音的水平：435.89+/-178.37 U/L 对 890.21+/-272.91 U/L， P【0.01 ) 。在封锁组的 TLR2 蛋白质的表示显著地在非封锁组与那相比减少了(免疫组织化学的方法， OPDTI：75.74+/-17.44 对 170.58+/-25.14， P【0.01；西方的污点的方法， A 珍视：125.89+/-15.49 对 433.91+/-35.53， P【0.01 ) 。后者与染色的 CD68 的变化相关(r = 0.745， P【0.05 ) 。另外，门静脉 TNF-alpha 的水平在非封锁组与那相比在封锁组减少了(84.45+/-14.73 ng/L 对 112.32+/-17.56 ng/L， P【0.05 ) ，但是在假冒的组仍然比那高(84.45+/-14.73 ng/L 对 6.07+/-5.33 ng/L， P【0.01 ) 。结论：KC 的函数的抑制可以保护肝免于 I/R 损害经由在 TLR2 的表达式的规定下面。

Structural and functional aspects of the liver and liver sinusoidal cells in relation to colon carcinoma metastasis

Nowadays, liver metastasis remains difficult to cure. When tumor cells escape and arrive in the liver sinusoids, they encounter the local defense mechanism specific to the liver. The sinusoidal cells have been widely described in physiologic conditions and in relation to metastasis during the past 30 years. This paper provides an 'overview' of how these cells function in health and in diseases such as liver metastasis.

Umbilical cord-derived mesenchymal stem cells alleviate liver fibrosis in rats

AIM: To evaluate the efficacy of umbilical cord-derived mesenchymal stem cells(UC-MSCs) transplantation in the treatment of liver fibrosis.METHODS: Cultured human UC-MSCs were isolated and transfused into rats with liver fibrosis induced by dimethylnitrosamine(DMN). The effects of UC-MSCs transfusion on liver fibrosis were then evaluated by histopathology; serum interleukin(IL)-4 and IL-10 levels were also measured. Furthermore, Kupffer cells(KCs) in fibrotic livers were isolated and cultured to analyze their phenotype. Moreover, UC-MSCs were cocultured with KCs in vitro to assess the effects of UCMSCs on KCs' phenotype, and IL-4 and IL-10 levels were measured in cell culture supernatants. Finally, UCMSCs and KCs were cultured in the presence of IL-4 antibodies to block the effects of this cytokine, followed by phenotypical analysis of KCs.RESULTS: UC-MSCs transfused into rats were recruited by the injured liver and alleviated liver fibrosis, increasing serum IL-4 and IL-10 levels. Interestingly, UC-MSCs promoted mobilization of KCs not only in fibrotic livers, but also in vitro. Co-culture of UC-MSCs with KCs resulted in increased production of IL-4 and IL-10. The addition of IL-4 antibodies into the coculture system resulted in decreased KC mobilization.CONCLUSION: UC-MSCs could increase IL-4 and promote mobilization of KCs both in vitro and in vivo, subsequently alleviating the liver fibrosis induced by DMN.

YKL40 expression in CD14^+ liver cells in acute and chronic injury

AIM:To demonstrate that CD14 + cells are an important source of the growth factor YKL40 in acute and chronic liver damage.METHODS:Rats were inoculated with one dose of CCl4 to induce acute damage.Liver biopsies were obtained at 0,6,12,24,48 and 72 h.For chronic damage,CCl4 was administered three days per week for 6 or 8 wk.Tissue samples were collected,and cellular populations were isolated by liver digestion and purified by cell sorting.YKL40 mRNA and protein expression were evaluated by realtime polymerase chain reaction and western blot.RESULTS:Acute liver damage induced a rapid increase of YKL40 mRNA beginning at 12 h.Expression peaked at 24 h,with a 26fold increase over basal levels.By 72 h however,YKL40 expression levels had nearly returned to control levels.On the other hand,chronic damage induced a sustained increase in YKL40 expression,with 7and 9fold higher levels at 6 and 8 wk,respectively.The pattern of YKL40 expression in different subpopulations showed that CD14+cells,which include Kupffer cells,are a source of YKL40 after acute damage at 72 h[0.09 relative expression units(REU)]as well as after chronic injury at 6 wk(0.11 REU).Hepatocytes,in turn,accounted for 0.06 and 0.01 REU after 72 h(acute)or 6 wk(chronic),respectively.The rest of the CD14cells(including T lymphocytes,B lymphocytes,natural killer and natural killer T cells) yielded 0.07 and 0.15 REU at 72 h and 6 wk,respectively.YKL40 protein expression in liver was detected at 72 h as well as 6 and 8 wk,with the highest expression relative to controls(11fold;P≤0.05)seen at 6 wk.Macrophages were stimulated by lipopolysaccharide.We demonstrate that under these conditions,these cells showed maximum expression of YKL40 at 12 h,with P<0.05 compared with controls.CONCLUSION:Hepatic CD14 + cells are an YKL40 mRNA and protein source in acute and chronic liver injury,with expression patterns similar to growth factors implicated in inflammationfibrogenesis.