Corneal Opacity: Cell Biological Determinants of the Transition From Transparency to Transient Haze to Scarring Fibrosis,and Resolution,After Injury

PurposeTo highlight the cellular, matrix, and hydration changes associated with opacity that occurs in the corneal stroma after injury.MethodsReview of the literature.ResultsThe regulated transition of keratocytes to corneal fibroblasts and myofibroblasts, and of bone marrow-derived fibrocytes to myofibroblasts, is in large part modulated by transforming growth factor beta (TGFβ) entry into the stroma after injury to the epithelial basement membrane (EBM) and/or Descemet''s membrane. The composition, stoichiometry, and organization of the stromal extracellular matrix components and water is altered by corneal fibroblast and myofibroblast production of large amounts of collagen type I and other extracellular matrix components—resulting in varying levels of stromal opacity, depending on the intensity of the healing response. Regeneration of EBM and/or Descemet''s membrane, and stromal cell production of non-EBM collagen type IV, reestablishes control of TGFβ entry and activity, and triggers TGFβ-dependent myofibroblast apoptosis. Eventually, corneal fibroblasts also disappear, and repopulating keratocytes reorganize the disordered extracellular matrix to reestablish transparency.ConclusionsInjuries to the cornea produce varying amounts of corneal opacity depending on the magnitude of cellular and molecular responses to injury. The EBM and Descemet''s membrane are key regulators of stromal cellularity through their modulation of TGFβ. After injury to the cornea, depending on the severity of the insult, and possibly genetic factors, trace opacity to severe scarring fibrosis develops. Stromal cellularity, and the functions of different cell types, are the major determinants of the level of the stromal opacity.     

Inhibition of lymphokine-activated killer cells generation in vitro by soluble factors released from mixed human tumor and peripheral blood mononuclear adherent cells culture

Background: A variety of molecules produced by both tumor cells and normal cells reduce the activity of lymphokine-activated killer (LAK) cells. We tested the possible cross-regulation of mel-624 melanoma cells and adherent peripheral blood mononuclear cells (PBMCs) in affecting LAK cell activity. Methods: PBMC adherent cells were cultured together with mel-624 melanoma cells. Supernatant was transferred to a 4-day LAK cells generation culture consisted of PBMC nonadherent cells and interleukin-2. LAK cytotoxic activity was tested in a 4-hour assay against Daudi tumor cells prelabeled with sodium ⁵¹chromate. Results: The supernatant produced within the first 48 hours of mixed mel-624 melanoma cell and adherent PBMC culture substantially (by 69 percent) reduced the generation of LAK cells, whereas the supernatant from either tumor culture or adherent PBMC culture had no effect. The inhibitory effect was manifested on the generation of LAK cells when autologous nonadherent cells were cultured with 1,000 units/ml IL-2, but there was no effect on mature LAK cell cytotoxic activity. Inhibition of LAK cell generation was partially dependent on protein synthesis and was not mediated by transforming growth factor β (TGF-β). Conclusion: Our results point toward the production of soluble, yet unidentified proteins, in mixed tumor-adherent PBMC cultures, which substantially reduced the induction of LAK cells in culture.     

Seed, soil and secreted hormones: Potential interactions of breast cancer cells with their endocrine/paracrine microenvironment and implications for treatment with bisphosphonates

The process of formation of metastasis is undoubtedly inefficient, with the majority of disseminated tumour cells perishing in their metastatic environment. Their ability to survive is determined by their intrinsic abilities, with emerging evidence of the importance of cancer stem cells possessing self propagating potential, but also the interaction with the premetastatic niche, which may either help or hinder their formation into micrometastasis, thus influencing recurrence and survival in breast cancer patients. Use of the bone targeted agents bisphosphonates in the adjuvant setting has been extensively studied in large clinical trials, and demonstrated an interesting interplay with the endocrine microenvironment, with postmenopausal women or premenopausal women receiving ovarian suppression therapy gaining a survival advantage compared to pre/perimenopausal women. The interaction between the endocrine hormones and the paracrine TGFβ growth factors may provide an explanation for the differences seen according to ovarian function in the response to bisphosphonates. In this review the evidence of interplay between ovarian endocrine hormones, TGFβ paracrine growth factors and bisphosphonates will be presented, and subsequent influence on breast cancer cells in the bone pre-metastatic niche hypothesised.     

The protective effect of smilax glabra extract on advanced glycation end products-induced endothelial dysfunction in HUVECs via RAGE-ERK1/2-NF-κB pathway

Ethnopharmacological relevance

Smilax glabra Roxb. (SGR) is a traditional Chinese herb that has been used in folk for the treatment of diabetic vascular complications. Advanced glycation end products (AGEs)-induced endothelial dysfunction has been thought to be a major cause of diabetic vascular complications. The present study was conducted to investigate the protective effect of SGR extract on AGEs-induced endothelial dysfunction and its underlying mechanisms.

Materials and methods

Human umbilical vein endothelial cells (HUVECs) were exposed to 200 μg/ml AGEs to induce endothelial dysfunction. Acridine orange/ethidium bromide (AO/EB) fluorescence assay and Annexin-V/PI double-staining were performed to determine endothelium apoptosis. Dihydroethidium (DHE) fluorescence probe, SOD and MDA kits were used to evaluate oxidative stress. The effect of SGR extract on AGEs-induced TGF-beta1 expression was determined by immunocytochemistry and western blotting. Attenuations of SGR extract on receptor for AGEs (RAGE) expression, extracellular regulated protein kinases (ERK1/2) activation and NF-κB phosphorylation were determined by immunofluorescence assay and western blotting. The blockade assays for RAGE and ERK1/2 were carried out using a specific RAGE-antibody (RAGE-Ab) or a selective ERK1/2 inhibitor PD98059 in immunofluorescence assay.

Results

The pretreatment of SGR extract (0.125, 0.25 and 0.5 mg crude drug/ml) significantly attenuated AGEs-induced endothelium apoptosis, and down-regulated TGF-beta1 protein expression in HUVECs. It was also well shown that SGR extract could down-regulate dose-dependently ROS over-generation, MDA content, TGF-beta1 expression, ERK1/2 and NF-κB activation whereas increase significantly SOD activity. Furthermore, the AGEs-induced ERK1/2 activation could be attenuated by the blockade of RAGE-Ab (5 μg/ml) while the NF-κB activation was ameliorated by ERK1/2 inhibitor PD98059 (10 μM).

Conclusion

These results indicated that SGR extract could attenuate AGEs-induced endothelial dysfunction via RAGE-ERK1/2-NF-κB pathways. Our findings suggest that SGR extract may be beneficial for attenuating endothelial dysfunction in diabetic vascular complications.     

TGF-β1和CNTF在大鼠移植神经干细胞后的损伤脊髓中的表达

目的 研究在受损伤脊髓移植神经干细胞后对其TGF-β1和CNTF表达的影响.方法 将正常成年SD雌性大鼠35只,分为:单纯脊髓全横断组、假手术组、NSCs移植组.NSCs移植组在脊髓全横断后第7天时进行NSCs移植,其它2组不移植NSCs;通过RT-PCR测定脊髓损伤局部头侧在移植术后3,7,14 d TGF-β1和CNTF的表达.结果 移植术后3 d,7 d,单纯全横断组TGF-β的表达大于神经干细胞组.CNTF仅在术后7 d,前者表达大于后者,其余时间段2组间2因子的表达无统计学意义.结论 神经干细胞移植使脊髓损伤局部TGF-β1的表达降低,但对CNTF表达的影响不大.     

慢性氟中毒对小鼠切牙胚内釉上皮TGF-beta1表达的影响

目的 :观察慢性氟中毒对小鼠切牙胚内釉上皮表达 TGF- beta1的影响 ,探讨TGF- beta1在氟牙症发生机制中的作用。方法 :给小鼠分别喂以含 0、5 0、1 0 0 ppm Na F的饮水 ,6周后免疫组化观察结果。结果 :图像分析显示加氟组 TGF- beta1的表达水平低于空白组。结论 :氟可能通过抑制 TGF- beta1的表达干扰内釉上皮的分化和基质分泌 ,导致氟牙症的发生。     

阿托伐他汀联合rhBNP治疗对急性心力衰竭患者血浆TGF-β1与心功能的影响

目的 研究急性心力衰竭(AHF)患者经阿托伐他汀与外源性脑利钠肽(rhBNP)治疗后血浆转化生长因子-β1(TGF-β1)与心功能的关系.方法 选择AHF患者116例,依据随机数字表法将患者分成观察组和对照组,各58例,两组均给予常规治疗,对照组加用阿托伐他汀,观察组在对照组的基础上另加用rhBNP治疗,对比两组血浆N末端脑钠肽原(NT-proBNP)及TGF-β1水平,心功能指标以及治疗前后的NYHA分级,分析指标间的相关性.结果 治疗后组内比较,两组的血浆NT-proB-NP及TGF-β1水平均明显低于治疗前,差异有统计学意义(P<0.05).治疗后组间比较,观察组的血浆NT-proBNP(334.28±121.06)ng·L-1及TGF-β1水平(134.13±26.13)ng·L-1均明显低于对照组的(510.79±114.63)ng·L-1及(280.29±27.64)ng·L-1,差异有统计学意义(P<0.05).治疗后组内比较,两组的左室射血分数(LVEF)明显高于治疗前,左心室舒张末期容积(LVEDV)及左心室收缩末期容积(LVESV)水平明显低于治疗前,差异有统计学意义(P<0.05).治疗后组间比较,观察组的LVEF(40.74±5.18)％ 明显高于对照组的(38.20±3.25)％,LVEDV(105.24±11.38)mL及LVESV水平(51.29±9.36)mL明显低于对照组的(111.87±10.63)mL及(60.39±8.72)mL,差异有统计学意义(P<0.05).治疗后观察组的NYHA分级明显低于对照组,差异有统计学意义(P<0.05).根据Spearman法分析相关性发现,患者血浆NT-proBNP及TGF-β1均与NYHA分级呈正相关(r=0.721,0.764;均P<0.05).结论 阿托伐他汀联合rhBNP治疗AHF能够明显降低患者的血浆TGF-β1水平,并改善其心功能,效果明显,值得推荐.     

肾复康对肾纤维化模型大鼠转化生长因子-β_1、Smad2、Smad7表达的影响

目的:评价肾复康对纤维化模型大鼠的疗效和对肾组织转化生长因子-β_1(TGF-β_1)、Smad2、Smad7表达的影响。方法:选取SD大鼠70只,完全随机分为假手术组、肾复康组及模型组,其中肾复康组及模型组均接受肾间质纤维模型制备,将造模第2天肾复康组接受不同剂量肾复康灌胃,对照组及假手术组接受同等体积的生理盐水灌胃,均干预21 d。干预结束收集各组24 h尿液,检测24 h尿蛋白(24 UP)、血肌酐(SCr)、血尿素氮(BUN)水平的变化,并断头取材,用苏木精-伊红(HE)染色评价各组肾组织的病理变化,免疫组化法检测各组肾组织TGF-β_1的变化,用Western blotting法检测Smad2、Smad7水平。结果:与假手术组比较,肾复康组及模型组24 UP、SCr及BUN水平明显升高,差异有统计学意义(P 0. 05);与模型组比较,肾复康组24 UP、SCr及BUN水平有所下降,差异有统计学意义(P 0. 05),且随着肾复康剂量升高趋势更明显。与假手术组比较,肾复康组及对模型组肾组织病理学评分均明显升高,其中肾复康组评分低于对照组,差异有统计学意义(P 0. 05)。随着肾复康剂量的增加病理学评分逐渐下降;假手术组肾组织仅有少量TGF-β_1、Smad2表达,模型组Smad2、TGF-β1呈高表达,随着肾复康剂量的增加Smad2、TGF-β_1水平逐渐下降。造模后Smad7水平下降,肾复康干预后Smad7水平有所上调,并随着水平的增加而上调趋势更明显。结论:肾复康可明显改善肾间质纤维化模型大鼠病情,其作用机制可能与介导肾脏组织TGF-β_1、Smad2、Smad7有关,且具有剂量依赖性     

Chemotactic response of osteoblast-like cells to transforming growth factor beta

Transforming growth factor beta (TGF-beta) was tested for its ability to stimulate a chemotactic response in two clonal rat osteosarcoma (ROS) cell lines, 17/2 and 25/1. TGF-beta stimulated dose-dependent chemotaxis in both cell lines. In serum-containing media, maximal response was seen at a concentration of 500 fg (10⁻¹⁵g)/mL for the ROS 17/2 cells and 25 fg/mL for the ROS 25/1 cells. In serum-free media, the maximal chemotactic response to TGF-beta occurred at 5 fg/mL for both the ROS 17/2 and 25/1 cells. TGF-beta was not mitogenic at these dosages. The results indicate that TGF-beta could act as a chemoattractant for osteogenic cells in both demineralized bone matrix induced osteogenesis and in normal bone remodeling.     

Review: The enigmatic role of endoglin in the placenta

The cellular expression, structure and function of endoglin, and its implication in several vascular disorders remain enigmatic, even 30 years after its discovery. Endoglin (CD105) is a homodimeric glycoprotein (180 kDa) constitutively expressed in the vascular endothelium. It is essential for cardiovascular development and mutations in the ENG gene lead to Hereditary Hemorrhagic Telangiectasia, a disorder characterized by arteriovenous malformations. Endoglin is also expressed in the syncytiotrophoblast throughout pregnancy, but transiently upregulated in the extravillous trophoblast of anchoring villi. Endoglin modulates responses to several TGF-β superfamily ligands and is essential for the negative regulation by TGF-β isoforms 1 and 3 of extravillous trophoblast differentiation. Membrane endoglin binds endothelial NO synthase and regulates its activation and vasomotor tone. There is also a circulating soluble form of endoglin (sEng; 65 kDa); its levels in the serum of women with preeclampsia are increased and correlated with disease severity. The exact sequence of sEng is still unresolved and the proposed mechanism of release from the syncytium by metalloproteases would not yield the expected size protein. The nature of the ligand sequestered by sEng is also an enigma. sEng is said to block the effects of TGF-β on NO-mediated vasorelaxation. However, sEng alone cannot scavenge these ligands for which it has very low affinity. sEng binds with high affinity to BMP9, which stimulates secretion from endothelial cells of the vascoconstrictor endothelin-1, also implicated in endothelial cell stabilization. It remains to be determined if scavenging of circulating BMP9 by sEng is important in preeclampsia and regulation of hypertension.