Effects of copper and cross-linking on the extracellular matrix of tissue-engineered arteries

In many cases, the mechanical strengths of tissue-engineered arteries do not match the mechanical strengths of native arteries. Ultimate arterial strength is primarily dictated by collagen in the extracellular matrix. but collagen in engineered arteries is not as dense, as organized, or as mature as collagen in native arteries. One step in the maturation process of collagen is the formation of hydroxylysyl pyridinoline (HP) cross-links between and within collagen molecules. HP cross-link formation, which is triggered by the copper-activated enzyme lysyl oxidase, greatly increases collagen fibril stability and enhances tissue strength. Increased cross-link formation, in addition to increased collagen production, may yield a stronger engineered tissue. In this article, the effect of increasing culture medium copper ion concentration on engineered arterial tissue composition and mechanics was investigated. Engineered vessels grown in low copper ion concentrations for the first 4 weeks of culture, followed by higher copper ion concentrations for the last 3 weeks of culture, had significantly elevated levels of cross-link formation compared to those grown in low copper ion concentrations. In contrast, vessels grown in high copper ion concentrations throughout culture failed to develop higher collagen cross-link densities than those grown in low copper ion concentrations. Although the additional cross-linking of collagen in engineered vessels may provide collagen fibril stability and resistance to proteolysis, it failed to enhance global tissue strength.     

骨髓间充质干细胞复合组织工程化脱细胞真皮基质构建组织工程皮肤

目的：体外培养扩增SD大鼠骨髓间充质干细胞（bone marrow mesenchymal stem cells,BMSCs），复合组织工程化脱细胞真皮基质构建组织工程皮肤，为进一步临床应用奠定基础。方法：将SD大鼠骨髓间充质干细胞进行体外培养扩增后，以生长状态良好的骨髓间充质干细胞接种于制备好的组织工程化脱细胞真皮支架上，进行体外联合培养，构建组织工程皮肤。观察细胞生长情况及组织工程皮肤结构。结果：体外培养的SD大鼠骨髓间充质干细胞生长良好，传代扩增容易，组织工程化脱细胞真皮基质去细胞完全，骨髓间充质干细胞在脱细胞真皮基质中生长良好，可体外构建组织工程皮肤。结论：利用体外扩增培养的骨髓间充质干细胞及制备的组织工程化脱细胞真皮基质可以体外联合构建组织工程皮肤。     

Cytoskeletal and extracellular matrix proteins in cerebral arteries following subarachnoid hemorrhage in monkeys.

It is unclear if vasospasm after subarachnoid hemorrhage (SAH) is predominantly due to smooth-muscle contraction, proliferative vasculopathy, or other changes within the arterial wall such as fibrosis or change in smooth-muscle phenotype. In this study, immunohistochemistry was used to examine changes in extracellular and cytoskeletal proteins in cerebral arteries after SAH that might support one of these mechanisms. Following baseline cerebral angiography, bilateral SAH was created in nine monkeys. Three animals each were killed 7, 14, or 28 days after SAH. Cerebral angiography was repeated on Day 7 in all animals and immediately prior to sacrifice in animals killed on Days 14 and 28. Both middle cerebral arteries and four control basilar arteries were examined using fluorescent antibody techniques with antisera to alpha-actin, myosin, fibronectin, fibrinogen, vimentin, desmin, laminin, and collagens (types I, III, IV, and V). Angiography showed that vasospasm was most severe on Day 7, present but resolving on Day 14, and completely resolved by Day 28. Microscopic study of arterial sections and blinded review of microphotographs of arterial sections by five independent observers did not reveal changes in intensity of density of staining for collagens, desmin, myosin, laminin, or alpha-actin in the tunica media of tunica adventitia. Fibronectin immunoreactivity increased 14 days after SAH. Seven days after SAH, occasional areas of tunica media showed immunoreactivity to fibrinogen. On Day 28, intimal thickening was observed in four of six middle cerebral arteries and this tissue demonstrated immunoreactivity to alpha-actin, myosin, vimentin, desmin, fibronectin, laminin, and each type of collagen. No significant increases in the number of intimal cells showing immunoreactivity to alpha-actin were seen and no significant changes in the hydroxyproline content of cerebral arteries developed at any time after SAH. These results suggest that rigidity and lumen narrowing of vasospasm are not due to increased arterial collagen, although other proteins in the arterial wall or an alteration in cross-linking of existing proteins could produce these changes. There is no indication that smooth-muscle contractile proteins change during vasospasm or that increases in the number of alpha-actin-containing myointimal cells contribute to vasospasm. The occurrence of intimal thickening and increased tunica media fibronectin after vasospasm suggests that vasospasm damages smooth muscle, possibly as a result of intense prolonged smooth-muscle contraction.     

Effects of retinoids on the TGF-beta system and extracellular matrix in experimental glomerulonephritis.

Transforming growth factor-beta1 (TGF-beta 1) overexpression plays a key role in the glomerular accumulation of extracellular matrix proteins in renal disease. Retinoids have previously been shown to significantly limit glomerular damage in rat experimental glomerulonephritis. Therefore, the effects of all-trans retinoic acid and isotretinoin on the components of the TGF-beta system and extracellular matrix proteins in anti-Thy1.1-nephritis (Thy-GN) were investigated. Vehicle-injected control rats were compared with rats treated with daily subcutaneous injections of 10 mg/kg body wt all-trans retinoic acid or 40 mg/kg body wt isotretinoin (n = 9 per group) either with a pretreatment (day -2 through 8) or posttreatment protocol (day +3 through 8), i.e., starting before or after induction of Thy-GN, respectively. Urinary TGF-beta 1 excretion was 60% lower in all-trans retinoic acid-treated animals with Thy-GN (P < 0.025). The increase of cortical TGF-beta 1 gene expression in Thy-GN rats was significantly attenuated with all-trans retinoic acid and even more with isotretinoin treatment as compared with untreated animals (P < 0.025). Cortical expression of TGF receptor II, but not receptor I gene expression, was significantly lower in animals treated with all-trans retinoic acid or isotretinoin (P < 0.05). In all-trans retinoic acid-treated animals with Thy-GN, the increase of glomerular TGF-beta 1 protein (P < 0.008) and TGF-beta 1 (P < 0.025) and TGF receptor II mRNA (P < 0.015) was significantly less. Immunohistochemistry revealed less glomerular staining for TGF-beta 1 and TGF receptor II in the presence of all-trans retinoic acid. TGF-beta 1 immunostaining was not restricted to monocytes and macrophages, as indicated by double-staining. Glomerular staining for collagen IV and collagen III was less in animals treated with isotretinoin (P < 0.02 for both) in contrast to all-trans retinoic acid, whereas fibronectin remained unchanged. It was concluded that the beneficial effects of retinoids on glomerular damage are presumably due to a marked reduction in renal TGF-beta 1 and TGF receptor II expression.     

Tissue-specific effects of aldose reductase inhibition on fluorescence and cross-linking of extracellular matrix in chronic galactosemia. Relationship to pentosidine cross-links

Chronic experimental hyperglycemia mediated by galactose has been shown to induce browning and cross-linking of rat tail tendon collagen that could be duplicated in vitro by nonenzymatic galactosylation. To investigate the nature of these changes, Sprague-Dawley rats were placed on a 33% galactose diet without and with sorbinil for 6 and 12 mo. Collagen-linked fluorescence and pentosidine cross-links increased with age and galactosemia in tail tendons (P less than 0.001) and skin but were essentially unresponsive to aldose reductase inhibition (ARI). In contrast, tendon breaking time in urea, a likely parameter of cross-linking, was markedly improved (P less than 0.001) by ARI. Fluorescence that was inhibited by sorbinil treatment was increased in pepsin and proteinase K digest of aortic tissue from galactosemic rats (P less than 0.001), but impaired enzymatic digestibility was not observed. Systolic blood pressure as potential consequence of aortic stiffening was not increased in galactosemia. These data suggest that fluorescence in skin and tendon might be in part due to advanced glycosylation and pentosidine formation because these were not decreased by ARI. However, they also suggest that nonfluorescent cross-links may also be forming because, in contrast to fluorescence, tail tendon breaking time was partly corrected by ARI. Thus, it appears that extracellular matrix changes in chronic galactosemia are complex, being partly attributable to advanced glycosylation and partly to polyol-pathway activation.     

钙三醇抑制肾间质成纤维细胞的活化

目的 通过观察钙三醇对肾间质成纤维细胞增殖和凋亡的影响，及其对转化生长因子（TGF）β1诱导的成纤维细胞转分化和细胞外基质(ECM)合成的干预作用，旨在探讨钙三醇抗肾间质纤维化的潜在效应及相关机制。 方法 体外培养大鼠肾间质成纤维细胞NRK-49F，分别以不同浓度TGF-β1（1、2、5和10 μg/L）和（或）不同浓度钙三醇（10－4、10－5、10－6、10－7、和10－8 mmol/L）进行干扰。MTT法观察细胞增殖情况；流式细胞术分析细胞周期和细胞凋亡改变；实时定量PCR和Western印迹法分别检测细胞内α平滑肌肌动蛋白（α-SMA）、结缔组织生成因子（CTGF）及纤连蛋白（FN）的mRNA和蛋白表达。 结果 钙三醇能明显抑制正常和TGF-β1（5 μg/L）诱导的NRK-49F细胞增殖（P < 0.01）。经不同浓度钙三醇（10－4、10－5、10－6、10－7、和10－8 mmol/L）作用48 h后，NRK-49F细胞G2/S期细胞比例较TGF-β1刺激组均明显减少（分别为25.88%、21.81%、21.73%、23.28%、23.61%比27.42%，均P < 0.05），但对细胞凋亡无明显影响。NRK-49F细胞经TGF-β1刺激后，其α-SMA、CTGF、FN mRNA表达量显著上升，并在TGF-β1 1~5 μg/L的范围内呈剂量依赖效应。钙三醇能明显抑制TGF-β1诱导的α-SMA、CTGF、FN mRNA表达上调（均P < 0.05），而不同钙三醇浓度干预组之间差异无统计学意义。钙三醇能显著降低TGF-β1诱导的α-SMA和FN蛋白表达（P < 0.05）。 结论 钙三醇可通过G1期停滞抑制大鼠肾间质成纤维细胞增殖，但不影响凋亡。钙三醇具有拮抗 TGF-β1致肾间质纤维化的潜在作用。     

血竭提取物对成纤维细胞增殖及合成透明质酸的影响

目的 研究血竭提取物对成纤维细胞生物学作用的影响.方法 将血竭经过氯仿、乙酸乙酯、乙醇依次回流提取分别得到3种血竭提取液,培养液稀释后行成纤维细胞培养.噻唑蓝法MTT检测浓度分别为0.002、0.02、0.2、2、20 mg/ml的血竭提取物,在0、12、24、36、48、60、72h7个检测点对体外培养成纤维细胞增殖的影响,并绘制最适浓度下细胞生长曲线.流式细胞术FCM分析最适浓度培养下成纤维细胞的细胞周期变化.应用放射免疫分析法检测0、12、24、36、48、60、72 h细胞培养上清液中透明质酸(hyaluronic acid,HA)含量.结果 血竭乙酸乙酯提取物在0.2～2 mg/ml浓度范围内,促进成纤维细胞增殖,且呈浓度依赖性,在2 mg/ml浓度值时促进作用最显著,处于S期的细胞[(25.80±3.10)％]较对照组[(7.50±0.70)％]显著增加(P＜0.01),在此条件下培养成纤维细胞,12～72 h实验组分泌量逐渐增加,但较对照组偏低,组间比较差异有统计学意义(P＜0.01).结论 血竭乙酸乙酯提取物具有显著促进成纤维细胞增殖作用,可能是血竭促进创面愈合的机制之一.     

低强度脉冲超声对兔膝骨关节炎软骨细胞外基质的影响及机制

目的：观察低强度脉冲超声（LIPUS）对兔膝骨关节炎软骨细胞外基质修复的影响并分析其作用机制。方法：选取60只成年雌性家兔,体质量（2.0±0.2）kg,采用随机抽签法分为实验组和对照组,每组30只。采用Hulth法复制膝骨关节炎模型。造模后2周,实验组予以LIPUS治疗,超声工作频率为（800±5%）KHz、最大输出空间平均声功率为（50±10%）mw/cm2,每日1次,每次20 min;对照组予以假LIPUS治疗（即操作与实验组相同,而探头无能量输出）。分别于治疗后第2、4、8周随机处死动物,每次实验组和对照组各10只。观察软骨大体改变、HE染色组织病理改变,采用免疫组化技术和RT-PCR技术分析软骨中的Ⅱ型胶原、蛋白多糖、MMP-3、MMP-7以及MMP-13,采用硝酸还原法分析软骨中的NO的含量。结果：同一时间点的实验组与对照组比较,实验组软骨的损伤程度比对照组轻微（P〈0.01）;实验组软骨中MMP-3、MMP-7、MMP-13和NO的含量均低于对照组（P〈0.01）;实验组软骨中Ⅱ型胶原和蛋白多糖的含量均高于对照组（P〈0.01）。结论：低强度脉冲超声可以通过降低软骨中MMP-3、MMP-7、MMP-13的表达,抑制NO的分泌,促进Ⅱ型胶原和蛋白多糖的合成,来加快损伤软骨的修复。     

Peritoneal mesothelial cells and the extracellular matrix

Continuous ambulatory peritoneal dialysis (CAPD) is an important treatment for patients with end‐stage renal failure. Long‐term success is dependent on the functional and structural integrity of the peritoneal membrane. Conventional peritoneal dialysis fluids are non‐physiological. They contain glucose at high concentrations to provide the osmotic drive for ultrafiltration, lactate to correct the metabolic acidosis of renal failure, and a low pH to prevent caramelization of glucose during heat sterilization. These components, in isolation or acting together, exert adverse influences on both the resident cellular and extracellular elements of the peritoneal membrane, as well as phagocytic cells which infiltrate the peritoneum during inflammation, culminating in detrimental structural and functional effects, compromising the viability of the peritoneum during dialysis. Peritoneal biopsy studies of patients on long‐term CAPD have demonstrated an intercellular space between adjacent mesothelial cells which allows the penetration of peritoneal dialysis fluid into the underlying submesothelium. This, together with episodes of peritonitis, can initiate a chronic inflammatory reaction within the peritoneum characterized by increased synthesis of matrix proteins. Perturbation of the regulatory mechanisms which govern the balance of synthesis and degradation of extracellular matrix can lead to progressive fibrosis. Human peritoneal mesothelial cells (HPMC) have been shown to synthesize fibronectin, laminin, collagens, proteoglycans and hyaluronan in vitro, and thus play a role in the pathogenesis of peritoneal fibrosis. This review will give an overview of extracellular matrix (ECM) synthesis by HPMC, how changes in the synthesis are affected by CAPD and postulate how these changes can compromise the dialytic properties of the peritoneum.     

高浓度氨基酸对大鼠肾小球系膜细胞增殖及细胞外基质合成的影响

目的 观察高浓度氨基酸、高糖、高浓度氨基酸高糖混合物对系膜细胞增殖及细胞外基质合成的影响。 方法 采用噻唑蓝（MTT）法、流式细胞仪法观察甘露醇（13.3 mmol/L）、高浓度氨基酸(较DMEM氨基酸浓度高1.5~6倍，渗透浓度13.3 mmol/L)、高糖（30.5 mmol/L）、高浓度氨基酸高糖混合物分别对系膜细胞增殖的影响；RT-PCR方法检测转化生长因子β1（TGF-β1）、Ⅳ型胶原(ColⅣ)和纤连蛋白（FN）mRNA的表达水平； 酶联免疫法检测TGF-β1水平；Western印迹法及放射免疫法测定ColⅣ、FN蛋白表达。 结果 （1）高浓度氨基酸、高糖、高浓度氨基酸高糖混合物均能刺激系膜细胞增殖，且具有时间依赖性，作用48 h时细胞增殖最明显；而高浓度氨基酸高糖混合物刺激细胞增殖作用最强。（2）高浓度氨基酸高糖混合物与细胞作用48 h，能明显影响细胞周期，使G0/G1期细胞减少，S期细胞增加。（3）高浓度氨基酸、高糖、高浓度氨基酸高糖混合物均能上调系膜细胞TGF-β1的基因表达；促进 TGF-β1蛋白合成增加[单位ng&#8226;ml－1&#8226;（105细胞）－1]（3023±85、3163±80、3321±85比1506±63，均P < 0.05)。（4）高浓度氨基酸、高糖、高浓度氨基酸高糖混合物均能上调系膜细胞ColⅣ、FN的基因表达；促进ColⅣ蛋白合成增加[单位ng&#8226;ml－1&#8226;（105细胞）－1]（16.78±2.56、18.65±2.56、22.83±2.45比10.22±2.54，均P < 0.01)；也可促进FN蛋白合成增加(18.47±2.34、13.58±3.13、17.98±2.56比8.22±2.54，均P < 0.05)。结论 高浓度氨基酸有类似于高糖样促系膜细胞增殖作用，可能通过TGF-β1通路促进细胞活性增加，细胞外基质分泌增多，且与高糖有协同作用。     

血管细胞外基质和尿道细胞外基质修复兔尿道缺损的比较研究

目的　寻求较理想的尿道修复材料。　方法　切取 10只家兔的腹主动脉和尿道各 3cm ,制备成血管细胞外基质 (VECM)和尿道细胞外基质 (UECM)。另 2 0只分别切除尿道 2 .5cm并随机分为VECM修复组和UECM修复组。两组均于修复术后 10d、3周、6周及 2 4周行组织再生情况研究 ;另于术后 10周、2 4周各取 2只行膀胱尿道造影 ;2 4周两组各取 2只行尿动力学检测和尿道镜检查。　结果　制备的VECM和UECM均为白色透明状 ,但VECM较UECM弹性和机械强度好。缺损修复术后10d ,基质中见单层上皮细胞且有血管长入ECM ,基质和受体尿道连接处有炎性细胞浸润 ;3周时基质管腔已完全被上皮细胞覆盖 ;6周时可见平滑肌细胞再生 ,炎性细胞消失 ;2 4周后其组织结构与正常尿道组织结构一致。VECM修复组和UECM修复组相比其组织再生过程无差异。尿动力学检测VECM修复组和UECM修复组的膀胱容量分别为 (30 .2± 1.6 )ml和 (32 .1± 1.4 )ml、尿道最高压分别为(15 .2 7± 1.36 )mmHg和 (14 .6 8± 1.6 5 )mmHg、尿道最低压分别为 (12 .4 9± 1.2 3)mmHg和 (11.96±0 .98)mmHg ,差异无统计学意义 (P >0 .0 5 )。膀胱尿道造影可见尿道壁完整光滑通畅 ,不能分辨移植区与正常组织 ,无尿液外渗 ,无梗阻及结石形成 ;尿道镜检查证实VECM修复组和U     

Effects of extracellular matrix components and dihydrotestosterone on the structure and function of human prostate cancer cells.

The extracellular matrix (ECM) has been shown to play a major role in cell structure and function. Several studies have demonstrated that the ECM can alter cell morphology and effect DNA synthesis and gene expression. The ECM also interacts with growth hormones which have been shown to be located in or near the ECM where they are believed to effect cell structure and function. In the nontransformed cell, these ECM and hormone-mediated effects appear to be tightly regulated and this is believed to be accomplished through cell receptor-tissue matrix interactions. We, therefore, undertook a study to determine the effects of a variety of ECM components and the adrogenic hormone dihydrotestosterone (DHT) on the structure and function of the human prostate cancer cell line, LNCaP. The effects of individual matrix components in the presence and absence of 1 nM DHT on the static and dynamic morphology, growth rate, and PSA production of the LNCaP cell line were studied. We determine that the ECM and DHT interact in complex ways to effect cell structure and function. DHT produced alterations in cytoplasmic structure that increased cell size and decreased the nuclear area/cytoplasmic area ratio. Dynamic cell structure as measured by cell motility was very sensitive to the ECM components and the presence of DHT. PSA and growth could be regulated by substratum and DHT and there was an inverse relationship between PSA production and growth rate. These data exemplify the complex interactions which occur between prostate cancer cells, ECM components, and exogenous DHT that are reflected in cell structure and function.     

脱细胞异体真皮基质组织补片用于腹股沟疝

目的 研究异体细胞外基质材料在疝修补术中的应用效果.方法 采用脱细胞异体真皮基质组织补片对腹股沟疝行无张力修补,观察其临床应用效果.结果 11例患者术后恢复良好,无并发症出现,随访3年均无不良主诉和复发表现.结论 异体细胞外基质材料可作为无张力疝修补术的理想天然生物材料.     

缓激肽对肾系膜细胞增殖与细胞外基质分泌的作用及有关机制的探讨

目的研究缓激肽(BK)对肾系膜细胞增殖与细胞外基质分泌的作用及探讨与血小板源生长因子BB(PDGF-BB)有关的ERK信号途径机制。方法BK单独或与PDGF-BB共同孵育系膜细胞后,以MTF法测细胞增殖情况;ELISA法测胶原(C01)Ⅰ、ColⅣ分泌;Western杂交测ERK蛋白表达。用BK受体特异阻断剂HOE-140、酪氨酸磷酸酶抑制剂(OV)和ERK途径阻断剂U0126预孵育,以BK和PDGF-BB共同刺激系膜细胞,Western杂交测ERK蛋白表达。结果BK(10-1000μg/L)可单独刺激系膜细胞增殖、ColⅠ和ColⅣ分泌及诱导ERK1/2磷酸化。20μg/L PDGF-BB预孵育也有类似作用,但可被BK呈剂量依赖性抑制。1μmol/L HOE-140和0.5 mmol/L OV能分别阻断BK对PDGF-BB-ERK1/2途径磷酸化的抑制作用,而U0126抑制了HOE-140和OV的作用。结论BK刺激系膜细胞增殖的作用主要是通过ERK途径介导的,与PDGF-BB共同作用时则呈拮抗作用,并且与ERK途径的受抑有关。缓激肽B2受体和酪氨酸磷酸酶参与了BK的双向调节作用。     

Current concepts of extracellular matrix

I dedicate this lecture to the memory of Professor Katsuyuki Fujii, MD. Early in his career Professor Fujii studied as a postdoctoral research fellow in my laboratory. He was one of my most outstanding students and has been acclaimed as a leader by the international orthopedic community.     

Effects of exogenous homocysteine on cellular proliferation and extracellular matrix production in cultured rat mesangial cells

SUMMARY: Homocysteine (HCY) is a thiol‐containing amino acid produced as a result of the demethylation of methionine. It has been proved that elevated HCY is associated with a high risk of arteriosclerotic cardiovascular disease. Although hyperhomocysteinaemia is observed frequently in patients with end‐stage renal disease, its role in the process of glomerulosclerosis is not clear. This study investigated the effects of exogenous HCY on proliferation, phenotype change and extracellular matrix production in rat mesangial cells (MCs). The results revealed that DNA synthesis in MCs, measured by the [³H]‐thymidine uptake, did not increase significantly when the cells were treated with HCY at concentrations of 5 × 10^?5, 5 × 10^?4 or 1 × 10^?3 mol/L, even though thymidine incorporation in MCs increased two‐ to fourfold using 20% fetal calf serum‐RPMI medium or platelet‐derived growth factor (20 ng/mL). A dose‐dependent increase in thymidine incorporation in vascular smooth muscle cells was also found when these cells were treated with HCY at similar concentrations (P < 0.01). The cell cycle was not changed when MCs were stimulated by HCY at different doses (5 × 10^?5, 5 × 10^?4 and 1 × 10^?3 mol/L) or at different time points (24, 48 and 72 h). Additionally, increased extracellular signal‐regulated kinase was observed in MCs induced by PDGF (10 ng/mL), but not by HCY (0.5 mmol/L) for 2–60 min. α‐Smooth muscle actin, detected using Western blot analysis, was not changed when MCs were exposed to 0.5 mmol/L HCY for 6, 12, 18, 24 and 36 h. Fibronectin and laminin, which are detected in the supernatant of cultured MCs by inhibition enzyme‐linked immunosorbent assay, were not changed when MCs were exposed to HCY (5 × 10^?4 mol/L) for 2, 4, 6 or 8 days. These results suggest that HCY has no effect on proliferation, phenotype change or extracellular matrix production in MCs. This indicates that HCY may not be a key factor contributing to the process of glomerulosclerosis.