Synapse loss from chronically elevated glucocorticoids: relationship to neuropil volume and cell number in hippocampal area CA3

Individuals with clinical disorders associated with elevated plasma glucocorticoids, such as major depressive disorder and Cushing's syndrome, are reported to have smaller hippocampal volume. To understand how the hippocampus responds at the cellular and subcellular levels to glucocorticoids and how such changes are related to volume measures, we have undertaken a comprehensive study of glucocorticoid effects on hippocampal CA3 volume and identified elements in the neuropil including astrocytic volume and cell and synapse number and size. Male Sprague-Dawley rats were injected with corticosterone (40 mg/kg), the primary glucocorticoid in rodents, or vehicle for 60 days. The CA3 was further subdivided so that the two-thirds of CA3 (nearest the dentate gyrus) previously shown to be vulnerable to corticosterone could be analyzed as two separate subfields. Corticosterone had no effect on neuropil volume or glial volume in the proximal subfield but caused a strong tendency for astrocytic processes to make up a larger proportion of the tissue and for volume of tissue made of constituents other than glial cells (primarily neuronal processes) to be smaller in the middle subfield. Within the neuropil, there were no cellular or subcellular profiles that indicated degeneration, suggesting that corticosterone does not cause prolonged damage. Corticosterone did not reduce cell number or cell or nonperforated synapse size but did cause a pronounced loss of synapses. This loss occurred in both subfields and, therefore, was independent of volume loss. Together, the findings suggest that volume measures can underestimate corticosterone effects on neural structure.     

自体骨髓单个核细胞移植治疗下肢慢性静脉溃疡的初步研究

目的探讨自体骨髓单个核细胞移植治疗下肢慢性静脉溃疡的疗效。方法 2009年5月-2010年9月,在采用大隐静脉剥脱术基础上,对17例下肢慢性静脉溃疡患者采用自体骨髓单个核细胞移植治疗(移植组),并与同期未采用细胞移植治疗的10例患者(对照组)比较疗效。移植组:男9例,女8例;年龄(33.3±6.1)岁。单纯大隐静脉曲张慢性溃疡11例,单纯深静脉瓣膜功能不全慢性溃疡6例。溃疡面积(4.39±2.46)cm2。病程3个月～6年。对照组:男4例,女6例;年龄(39.2±10.3)岁。单纯大隐静脉曲张慢性溃疡7例,单纯深静脉瓣膜功能不全慢性溃疡3例。溃疡面积(5.51±2.63)cm2。病程3个月～2年。两组按照临床病因解剖病理学分级(CEAP)均为C6级。两组患者一般资料比较差异均无统计学意义(P>0.05),有可比性。观察术后溃疡愈合情况;移植组于术前及术后3 d分别切取溃疡面肉芽组织行常规HE染色,免疫组织化学染色观察VEGF表达和微血管密度(microvessel density,MVD)。结果移植组患者溃疡愈合较快,其中15例愈合,1例好转,1例未愈合,中位愈合时间为22 d,四分位数间距为15 d;对照组溃疡愈合缓慢,其中7例愈合,3例未愈合,中位愈合时间57.5 d,四分位数间距为40 d。两组溃疡愈合时间比较差异有统计学意义(Z=0.001 4,P=0.002 7)。移植组HE染色显示,细胞移植后溃疡肉芽组织有丰富毛细血管结构;免疫组织化学染色示移植后MVD为(32.1±12.8)个,较移植前(22.1±6.7)个显著增加,差异有统计学意义(t=3.120,P=0.008);移植后VEGF表达阳性细胞百分比为8.05%±5.10%,较移植前(6.13%±4.20%)升高,但差异无统计学意义(t=1.150,P=0.268)。结论自体骨髓单个核细胞移植可以促进下肢慢性静脉溃疡肉芽组织增生,加速溃疡愈合。     

体外诱导BMSCs向软骨分化的方法研究进展

目的全面了解目前体外诱导BMSCs向软骨分化的方法,为软骨组织工程研究提供参考。方法广泛查阅近年来有关软骨组织工程中诱导BMSCs向软骨分化的文献,并进行综合分析。结果目前BMSCs诱导成软骨方法主要是添加外源性生长因子,其中TGF-β家族被公认为最重要的诱导和调节因子。其他重要的诱导方法包括添加多种化学因子、物理因素、转基因技术和微环境诱导等方法,但这些方法仍存在诱导效率低、诱导效果不稳定的问题。结论诱导方法的进展促进了BMSCs在软骨组织工程中的应用,建立更高效、简便、安全的诱导方法仍是软骨组织工程领域重要研究课题之一。     

Mechanical loading increased BMP‐2 expression which promoted osteogenic differentiation of tendon‐derived stem cells

This study aimed to investigate the effect of repetitive tensile loading on the expression of BMP‐2 and the effect of BMP‐2 on the osteogenic differentiation of tendon‐derived stem cells (TDSCs) in vitro. Repetitive stretching was applied to TDSCs isolated from rat patellar tendon at 0%, 4%, and 8%, 0.5 Hz. The expression of BMP‐2 was detected by Western blotting and qPCR. To study the osteogenic effects of BMP‐2 on TDSCs, BMP‐2 was added to the TDSC monolayer for the detection of ALP activity and calcium nodule formation in a separate experiment. TDSCs adhered, proliferated, and aligned along the direction of externally applied tensile force while they were randomly oriented in the control group. Western blotting showed increased expression of BMP‐2 in 4% and 8% stretching groups but not in the control group. Up‐regulation of BMP‐2 mRNA was also observed in the 4% stretching group. BMP‐2 increased the osteogenic differentiation of TDSCs as indicated by higher ALP cytochemical staining, ALP activity, and calcium nodule formation. Repetitive tensile loading increased the expression of BMP‐2 and addition of BMP‐2 enhanced osteogenic differentiation of TDSCs. Activation of BMP‐2 expression in TDSCs during tendon overuse might provide a possible explanation of ectopic calcification in calcifying tendinopathy. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:390–396, 2011     

Selective Targeting of Human Alloresponsive CD8+ Effector Memory T Cells Based on CD2 Expression

Costimulation blockade (CoB), specifically CD28/B7 inhibition with belatacept, is an emerging clinical replacement for calcineurin inhibitor‐based immunosuppression in allotransplantation. However, there is accumulating evidence that belatacept incompletely controls alloreactive T cells that lose CD28 expression during terminal differentiation. We have recently shown that the CD2‐specific fusion protein alefacept controls costimulation blockade‐resistant allograft rejection in nonhuman primates. Here, we have investigated the relationship between human alloreactive T cells, costimulation blockade sensitivity and CD2 expression to determine whether these findings warrant potential clinical translation. Using polychromatic flow cytometry, we found that CD8⁺ effector memory T cells are distinctly high CD2 and low CD28 expressors. Alloresponsive CD8⁺CD2^hiCD28^? T cells contained the highest proportion of cells with polyfunctional cytokine (IFNγ, TNF and IL‐2) and cytotoxic effector molecule (CD107a and granzyme B) expression capability. Treatment with belatacept in vitro incompletely attenuated allospecific proliferation, but alefacept inhibited belatacept‐resistant proliferation. These results suggest that highly alloreactive effector T cells exert their late stage functions without reliance on ongoing CD28/B7 costimulation. Their high CD2 expression increases their susceptibility to alefacept. These studies combined with in vivo nonhuman primate data provide a rationale for translation of an immunosuppression regimen pairing alefacept and belatacept to human renal transplantation.     

脓毒血症患者外周血Th17细胞与细胞因子表达的变化

目的：监测脓毒症患者外周血Th17细胞和细胞因子IL-17、IL-6的表达水平．探讨脓毒血症患者免疫功能变化的可能机制。方法：取2010年4月至11月住我院ICU病房的脓毒症患者62例。采用流式细胞术检测外周血Th17％（Th17／CD4＋T）。应用ELISA（酶联免疫吸附方法）检测血浆IL-17和IL-6的表达水平。同时选取来自我院查体中心的健康查体者30例作为对照组。结果：脓毒症患者外周血Th17％明显高于健康对照组[（6．94±1.95）比（1.91±0,32）％,P〈0．01];血浆IL-17,IL-6的表然亦最著高于对照组[（56．52±16．06）pg／ml比（19．59±1．98）pg／ml;（220,68±86．41）pg／ml比（24.39±0,87）Pg／ml]。患者血浆IL-17与IL-6表达水平里正相关（r=0．886．p〈0.01）。Th17的表达与IL-17、IL-6的表达亦呈正相关,（r1=20．846,r2=0．891．均P〈0．01）.结论：脓毒血症患者外周血中Th17％增加．血浆IL-17及IL-6表达水平亦升高．提示Th17可能参与脓毒症的发病机制。     

供者未成熟树突状细胞联合西罗莫司诱导大鼠皮肤移植物免疫耐受研究

目的：观察大鼠骨髓来源的未成熟树突状细胞（i mDCs）联合西罗莫司（SRL）在诱导大鼠同种异体皮肤移植免疫耐受中的协同作用。方法：以雄性Lewis大鼠为供者、Brown-Norway大鼠为受者,建立大鼠同种异体皮肤移植模型。对照（control）组术前不给予任何干预;未成熟树突状细胞（imDCs）组于术前7天经尾静脉注射供者骨髓来源的未成熟树突状细胞;西罗莫司（SRL）组于术后连续7天经胃管灌注西罗莫司;联合（imDCs＋SRL）组于术前7天经尾静脉注射供者骨髓来源的未成熟树突状细胞,并于术后连续7天经胃管灌注西罗莫司。结果：对照组、未成熟树突状细胞（imDC）组、西罗莫司（SRL）组、联合（imDCs＋SRL）组大鼠同种异体皮肤移植物术后存活时间分别为（8.25±1.75）（、10.25±1.91）（、10.64±2.50）（、21.38±2.97）天。方差分析提示组间差异有统计学意义（P〈0.05）;S-N-K检验提示除单独应用未成熟DC组与单独应用SRL组外,各组间的差异均有统计学意义（P〈0.05）。结论：供者骨髓来源未成熟树突状细胞可诱导大鼠同种异体皮肤移植免疫耐受;联合使用西罗莫司可延长移植皮片成活时间。     

诱导多潜能干细胞治疗脊髓损伤的研究现状与进展

脊髓损伤是困扰医学界的难题。目前临床上的治疗方法效果均不理想。近20年来,干细胞技术飞速发展,在神经疾病和神经损伤的动物模型中应用胚胎和成体干细胞,取得了肯定的结果。在细胞水平上为治疗神经损伤提供了新的前景。但是由于技术和伦理方面的问题,获得可以应用于人类的合适的细胞资源仍有许多困难。最近诱导多功能干细胞的发现,为自体同源移植治疗脊髓损伤提供了新方法。本文将以此为出发点,评估诱导多潜能干细胞向神经细胞分化的能力,以及在这一领域中的最新进展。     

异氟醚预处理对谷氨酸诱导大鼠神经元样PC12细胞凋亡的影响

目的 探讨异氟醚预处理对谷氨酸诱导大鼠神经元样PC12细胞凋亡的影响.方法 神经生长因子孵育5d的神经元样PC12细胞,以5×104个/ml密度接种于6 cm培养皿(3 ml/皿)或6孔板(2ml/孔),采用随机数字表法,将其随机分为4组(n=18):正常对照组(C组)、谷氨酸组(G组)、谷氨酸+异氟醚组(GI组)和谷氨酸+异氟醚+三磷酸肌醇受体拮抗剂光溜海绵素组(GIX组).C组不做任何处理;G组、GI组和GIX组均加入500 μmol/L谷氨酸,GI组和GIX组通入1.2％异氟醚2h,停止通入后10 min加入谷氨酸,GIX组通入异氟醚前即刻加入光溜海绵素100 nmol/L.于谷氨酸孵育20 min时,每组取6皿和6孔,收集细胞,采用流式细胞术检测细胞凋亡率和线粒体膜电位(MMP),采用显微荧光测量技术检测细胞内钙离子浓度([Ca2+]i).结果 与C组比较,G组和GIX组细胞凋亡率和[Ca2+]i升高,MMP降低(P＜0.01),GI组上述指标差异无统计学意义(P＞0.05);与G组比较,GI组和GIX组细胞凋亡率和[Ca2+]i降低,MMP升高(P＜0.05或0.01);与GI组比较,GIX组细胞凋亡率和[Ca2+]i升高,MMP降低(P＜0.01).结论 异氟醚预处理可抑制大鼠神经元样PC12细胞凋亡,其机制与激活内质网三磷酸肌醇受体,抑制内质网释放Ca2+,提高MMP有关.     

上皮-间质转化在胃肠道肿瘤中的研究进展

目的 介绍上皮-间质转化(EMT)在胃肠道肿瘤中的研究现状.方法 收集近年来国内、外有关EMT及其调节因子与胃肠道肿瘤关系的文献并作综述.结果 EMT是胚胎发育的一个基本过程,在成熟上皮细胞中EMT的异常激活可以降低细胞间黏附分子表达进而促进肿瘤的转移.上皮细胞表面标志物E-钙黏素表达抑制和EMT发生密切相关,E-钙黏素转录抑制因子可能在调节EMT过程中起重要作用,并且这些转录抑制因子在胃肠道肿瘤中呈明显高表达.此外,EMT的发生可能在胃肠道肿瘤干细胞形成过程中起重要作用.结论 EMT及其调节因子在胃肠道肿瘤发生、侵袭和转移过程中起了重要作用,对于EMT及其调节因子的研究可以为肿瘤发生机理提供新的视角,为肿瘤治疗提供新的靶点.