Retinal blood vessels are damaged in a rat model of NMDA-induced retinal degeneration

Retinal ischemia–reperfusion causes capillary degeneration but the mechanisms of damage are not well understood. The NMDA receptor plays an important role in neuronal damage after ischemia–reperfusion. Therefore, we determined whether retinal blood vessels are damaged structurally and functionally in a rat model of retinal degeneration induced by NMDA. At 7 days after a single intravitreal injection of NMDA (200 nmol) into the eye, loss of retinal ganglion cells and thinning of the inner plexiform layer were observed. Endothelial cells disappeared in some regressing vessels and empty basement membrane sleeves were left as remnants of the vessels. The number of basement membrane sleeves was increased in the NMDA-treated retina and non-perfused vessels were found in the injured retina. These results indicate that retinal blood vessels are damaged in the NMDA-induced retinal degeneration model. Neuronal cells may play a role in maintaining normal structure and function of the vasculature in the retina.     

Alzheimer's disease markers, hypertension, and gray matter damage in normal elderly

It is not well known whether Alzheimer's disease (AD) cerebrospinal fluid (CSF) biomarkers are associated with brain damage in cognitively normal elderly. The combined influence of CSF biomarkers and hypertension (HTN) on the gray matter (GM) is also not well described. One hundred fifteen cognitively healthy subjects (mean age 62.6 ± 9.5%, 62% women) received clinical assessment, a high resolution magnetic resonance imaging (MRI), and a lumbar puncture. The CSF levels of total tau (t-tau), hyperphosphorylated tau (p-tau(231)), amyloid beta (Aβ42/Aβ40), p-tau(231)/Aβ42, and t-tau/Aβ42 were dichotomized as "high" and "low" based on accepted cut off values. Statistical parametric mapping was used to examine MRI scans for regional GM density, studied as a function of the CSF markers, HTN, and combination of both. Global and medial temporal lobe (MTL) GM was also assessed. Voxel based morphometry revealed that higher t-tau was associated with lower GM density in the precunei. Subjects with higher p-tau(231) and p-tau(231)/Aβ42 had less GM in temporal lobes. Low Aβ42/Aβ40 was related to less GM in the thalami, caudate, and midbrain. Subjects with hypertension showed more GM atrophy in the cerebellum, occipital, and frontal regions. Simultaneous presence of elevated CSF AD biomarkers and HTN was associated with more GM atrophy than either marker individually, but no interaction effects were identified. In conclusion, in normal elderly CSF tau markers were associated predominantly with lower GM estimates in structures typically affected early in the AD process. In this presymptomatic stage when no cognitive impairment is present, AD biomarkers and HTN have additive effects on gray matter damage.     

The role of blood cells and of the vessel wall in the induction of intravascular coagulation

Summary Disseminated intravascular coagulation (DIC) is a threatened complication of infection, particularly with gram-negative bacteria. After a discussion of possible mechanims of activation of the extrinsic and intrinsic pathways of thrombin formation, it is concluded that the effects of endotoxins on endothelial cells and leukocytes most likely stand at the beginning of the chain of events which leads to manifest DIC.     

Mitochondrial energy conversion disturbance with decrease in ATP production as a source of systemic arterial hypertension

Despite numerous efforts, including recent genetic and molecular biology studies, the immediate cause of stationary elevated blood pressure (BP) in any kind of hypertension has not been satisfactorily explained. This review deals with the cellular mechanisms underlying decreased energy status documented in different tissues from experimental rat models of primary and secondary hypertension as well as the involvement of these abnormalities in the pathogenesis of the disease. Such analyses allow us to hypothesize that dysfunction of mitochondrial energy conversion, caused by distinct stimuli, including generalized disturbances of intracellular Ca²⁺ handling and mitochondria calcium overload found in primary hypertension, leads to uncoupling of oxidation and phosphorylation and attenuated ATP synthesis. Examples of arterial hypertension accompanied by mitochondrial uncoupling and cell ATP depletion (hyperthyroidism, cold hypertension, cyclosporine A intake, etc.) may be considered as an additional argument supporting this opinion. It means also that despite of differences in triggering mechanisms of mitochondrial dysfunction in all these models, the final outcome, i.e. decreased mitochondrial ATP production, is similar. Attenuated intracellular ATP content, in turn, results in the long-term maintenance of elevated BP by increased sympathetic outflow, whereas augmented ROS production following mitochondrial dysfunction lowers the capacity of the NO-dependent vascular relaxation. In the light of these data the cause of stationary elevated BP in chronic arterial hypertension should be regarded as a compensatory response to decreased mitochondrial ATP synthesis.     

Selective distribution of medial thickening in the renal vessels in experimental hypertension

Direct effects, especially the distribution of medial thickening due to chronic hypertension on the renal arterial tree, were examined pathologically and morphometrically in cats with one-kidney DOCA-salt hypertension. Twenty-one adult male cats were divided into three groups: (i) an experimental group of one-kidney DOCA-salt hypertension (12 cats): (ii) a uninephrectomized group without administration of DOCA and salt (four cats); and (iii) a group without uninephrectomy and administration of DOCA and salt (five cats). The duration of hypertension varied from 3 weeks to 4 months and the aortic blood pressure was monitored every 5 min. The increase of mean blood pressure (MBP) of the experimental group was 15–44 mmHg. A significant medial thickening of the right renal arterial tree was evaluated by a comparison of the right and left regression lines of each case between the midwall radius (R) and medial thickness (D) of arteries in a distended state. The evaluation was made separately for arteries with R values above or below 40 μm, because a regression line between R and D showed a maximum bend at a level of R from 30 to 40 μm. The arteries of the right kidney with a diameter less than 40 μm, corresponding to the interlobular arteries and afferent arterioles, showed significant medial thickening in six cases. Medial thickening was absent in other cats of the experimental group and cats of a control group given uninephrectomy alone. Increase of MBP during the hypertensive phase of these six cases was above 34.6 mmHG and all values of other cats without medial thickening were below this level. The renal arteries of the right kidney with a diameter larger than 40 μm showed medial thickening in only one cat. This preferential distribution of medial thickening of the interlobular arteries and afferent arterioles due to one kidney DOCA-salt hypertension was considered to be a direct effect of hypertension and a result of the specific functional (autoregulation of the renal blood flow) and structural features of these arteries.     

阻断血管内皮生长因子C促进角膜移植后新生淋巴管和血管的“分离生长”

BACKGROUND: Corneal lymphangiogenesis is beneficial to the transport of corneal antigenic materials, and accelerates the process of antigen presentation, thereby playing an important role in corneal immunity. However, due to the parallel outgrowth of corneal blood and lymphatic vessels in transplanted corneas, it is often difficult to accurately evaluate the role of corneal lymphatic vessels in allograft rejection. OBJECTIVE: To explore the development of corneal lymphangiogenesis and angiogenesis in transplanted rat corneas after the blockade of vascular endothelial growth factor C (VEGF-C). METHODS: 130 rats used to establish corneal allogenic transplantation models were equally randomized into two groups: the anti-VEGF-C group and the control group. VEGF-C was blocked in the anti-VEGF-C group by intraperitoneal injection of neutralizing monoclonal anti-VEGF-C antibody every other day for 2 consecutive weeks. Meanwhile, rats in control groups received intraperitoneal injections of saline. Corneal angiogenesis and lymphangiogenesis were characterized using whole mount immunofluorescence, and the immune rejection of the grafts was evaluated by scoring the rejection index (RI). In addition, the expression of VEGF-C was examined by real-time PCR. The relationship of corneal lymphangiogenesis and angiogenesis to RI in transplanted corneas was also characterized. RESULTS AND CONCLUSION: VEGF-C expression was markedly downregulated after VEGF-C blockade. Corneal lymphangiogenesis developed in parallel with corneal angiogenesis in the control group. While there was a mild reduction in blood vessel area (BVA) and a significant decrease in lymphatic vessel area (LVA) in the anti-VEGF-C group (P < 0.05). In addition, RI was positively correlated with BVA (P < 0.05) and LVA (P < 0.05) in the control group. However, although RI was significantly correlated with BVA (P < 0.05) in the anti-VEGF-C group, the correlation between RI and LVA was not statistically significant (P > 0.05). the graft survival time in the anti-VEGF-C group was significantly increased compared with that in the control group (P < 0.05). Our results show that the outgrowth of lymphatic vessels is separated from that of blood vessels in transplanted corneas by blocking VEGF-C. The blockade of VEGF-C has a significant role in preventing corneal lymphangiogenesis in corneal beds, which results in higher allograft survival rates. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

Ultrastructural investigation of peripheral arterial vessels in the cortex of rats with experimental hypertension.

The peripheral arterial blood vessels in the cerebrum of 36 experimental animals and 9 controls were studied by electron microscopy. In 5 rats of these renal hypertension was produced (the animals were sacrificed 3 to 15 days following the second operation). 24 animals were treated with depot angiotensin (0.02 to 2.5 mg/daily) for 3 hr up to 40 days, and 7 rats were neurotized for 1 to 41/2 months. The alterations of the cerebral vessels were distinctly different within these 3 models already in the early reactions. Thus, even in the first 14 days of the experiment with renal and angiotensinogenic hypertension alterations were observed that did never occur in the neurotized rats. There were always observed disturbances in permeability of the cerebral vessels, but they were never followed by such heavy wall insudations as usually noticed in the splanchnic vessels. The less frequent occurrence of hemorrhages and malacic processes in the rat brain is ascribed aside from the physiological properties of the brain supply, to genetic factors and the absence of arteriosclerotic burden to the vascular wall in the non-dietetically pretreated experimental animals.     

藏红花素促进颈动脉损伤小鼠体内EPCs动员及损伤血管的再内皮化

目的:研究藏红花素对颈动脉损伤小鼠外周血中内皮祖细胞(endothelial progenitor cells,EPCs)动员的影响及其作用机制。方法:利用导丝损伤的方法构建C57BL/6小鼠颈动脉损伤模型,动物分为假手术组(sham组)、生理盐水处理模型组(model组)和藏红花素低、中、高剂量(10、50和100μmol·kg~(-1)·L~(-1))处理组。在3 d时,利用流式细胞术检测各组颈动脉损伤小鼠体内外周血中EPCs动员情况;7 d时,利用酶联免疫吸附法检测各组颈动脉损伤小鼠外周血血清中促血管修复因子——血管内皮生长因子(vascular endothelial growth factor,VEGF)、基质细胞衍生因子1(stromal-derived factor-1,SDF-1)、碱性成纤维细胞生长因子(basic fibroblast growth factor,bFGF)、表皮生长因子(epidermal growth factor,EGF)和基质金属蛋白酶9(matrix metalloproteinase-9,MMP-9)的含量变化;14 d时,利用依文思蓝和苏木精-伊红染色分别检测各组颈动脉损伤小鼠损伤血管再内皮化和内膜增生情况;同时采用real-time PCR检测各组颈动脉损伤小鼠损伤段血管中促修复因子相关受体——血管内皮生长因子受体2(vascular endothelial growth factor receptor 2,VEGFR-2)、CXC趋化因子受体4(CXC chemokine receptor-4,CXCR4)、碱性成纤维细胞生长因子受体(basic fibroblast growth factor receptor,bFGFR)和表皮生长因子受体(epidermal growth factor receptor,EGFR)的mRNA表达水平。结果:与sham组相比,model组颈动脉损伤小鼠外周血中EPCs动员量和促血管修复因子VEGF、SDF-1、bFGF、EGF、MMP-9的含量上升(P0.05);损伤血管再内皮化面积下降而增生内膜面积和增生内膜与中层膜面积比显著升高(P0.05);损伤段血管中促修复因子相关受体VEGFR-2、CXCR4、bFGFR和EGFR的表达水平亦上升(P0.05)。而与model组相比,不同浓度藏红花素处理组颈动脉损伤小鼠外周血中EPCs动员量和促血管修复因子VEGF、SDF-1、bFGF、EGF、MMP-9含量均显著上升(P0.05);损伤血管再内皮化面积逐渐上升而增生内膜面积和增生内膜与中层膜面积比逐渐下降(P0.05);损伤段血管中促修复因子相关受体基因VEGFR-2、CXCR4、bFGF-R和EGFR的表达水平随之逐渐上升(P0.05)。结论:藏红花素能够促进颈动脉损伤小鼠体内EPCs细胞动员及损伤血管的再内皮化,从而对损伤血管发挥修复作用。     

Aging in the rat medial nucleus of the trapezoid body. III. Alterations in capillaries

The medial nucleus of the trapezoid body (MTB), a large cell group in the rat brainstem auditory pathway, undergoes significant cell loss and loss of synapses with advancing age [5,6]. The purpose of the present study was to examine the microvasculature of the MTB in rats of the following ages: 3 months (MO), 6 MO, 24 MO, 27 MO, and 33 MO. In rats aged 24 to 33 MO, the following ultrastructural changes were observed in MTB capillaries: (1) large cavitations or spaces within capillary basal laminae, and (2) membranous debris, indicative of cellular degeneration within leaflets of capillary basal lamina. The volume density ratio (VDR) of capillaries decreases significantly between 6 and 33 MO of age.     

The use of BDNF to enhance the patency rate of small-diameter tissue-engineered blood vessels through stem cell homing mechanisms

The patency rate of small-diameter tissue-engineered blood vessels is the determinant for their application in coronary artery bypass grafting. The coronary artery is innervated by vagus nerves. The origin of vagus nerves is rich in brain-derived neurotrophic factors (BDNF). We have investigated whether BDNF could improve the patency rate of small-diameter tissue-engineered blood vessels through promoting stem cell homing and paracrine activity. In vitro, we isolated early and late endothelial progenitor cells (EPCs) and found BDNF could promote single clone formation and paracrine function of EPCs, and could also induce the proliferation, migration and differentiation of late EPCs. BDNF could enhance the capturing of EPCs in parallel-plate flow chamber. Flow cytometric analysis and laser-scanning confocal microscope showed BDNF could enhance the mobilization and homing of C57BL/6 mouse EPCs after wire injury. Based on it, BDNF was coupled to the lumen surface of the blood vessel matrix material incubated with collagen through SPDP to construct BDNF-modified small-diameter tissue-engineered blood vessel. The blood vessel patency rate was significantly higher than that of control group 8 weeks after implantation in rats and the endothelialization level was superior to control. These results demonstrate that BDNF can effectively improve patency of small-diameter tissue-engineered blood vessels through stem cell homing and paracrine, and it is expected to play an important role in the construction of substitutes for coronary artery bypass grafting.     

一氧化碳对低氧性肺动脉高压的效应

目的:探讨外源性低浓度一氧化碳(CO)在低氧性肺动脉高压中的作用。方法:60只Wistar大鼠随机分为常氧组、低氧组、血晶素组、锡原卟啉组和低浓度CO组,每组12只。处理完毕后,右心导管法测定肺动脉平均收缩压和右心室压。杀鼠取肺组织,应用分光光度法测定肺组织HO-1活性,并进行常规免疫组织化学染色,应用逆转录多聚酶链式反应测定测定肺组织的HOmRNA水平。结果:①低浓度CO组肺动脉压为(18.52±3.24)mmHg,明显低于低氧组但仍高于常氧组(均为P＜0.01);②低浓度CO组HO-1活性为(1052.48±308.49)nmol·g^-1(protein),显著高于正常组(P＜0.01);③低浓度CO组HO-1蛋白表达水平均高于常氧组和低氧组(P＜0.01);④低浓度CO组HO-1mRNA水平的光密度值为2.63±0.18,显著高于正常组(P＜0.01)。结论:CO-HO系统参与了低氧性肺动脉高压的发病机制;低浓度CO可以有效促进HO-1mRNA表达,使HO-1活性和蛋白表达水平升高,进而部分降低肺动脉压力。     

Aging in the rat medial nucleus of the trapezoid body. I. Light microscopy

The medial nucleus of the trapezoid body (MTB), a cell group in the superior olivary complex, was examined in an age-graded series of rats for neuron loss, changes in the giant synaptic endings (chalices of Held) on MTB neurons, and accumulation of age pigment. Neuron counts were done on protargol-stained paraffin sections of MTBs from a series of 17 rats aged 2-3, 6, 18, and 24 months. Between 2-3 and 24 months a 34% decrease in the mean number of MTB neurons was observed. Significant loss (p less than 0.05) was first evident in the early portion of the life span, between 2-3 and 6 months. In thionin-stained sections, there was no change with aging in the proportions of three MTB neuron types: principal cells (approximately 82%), elongate cells (approximately 15%), and stellate cells (approximately 3%). In young adult rats, 25-26% of all MTB neurons were associated with identifiable chalices of Held in protargol stained sections. This ratio did not vary significantly with aging. Age pigment accumulation in the MTB was examined in 2 micrometers Araldite sections stained with toluidine blue. Age pigment deposits were larger and more numerous in the MTBs of old animals, but not as extensive as has been described previously in many other parts of the nervous system. This study is the first to report neuron loss in an animal brainstem nucleus.     

利钾尿肽与心钠素摩尔比在老年原发性高血压中的作用

目的:探讨利钾尿肽(KP)与心钠素摩尔比变化在老年原发性高血压发病中的意义。方法:用放射免疫分析方法测定老年高血压患者血浆、老年自发性高血压大鼠(SHR)血浆及心房和心室组织的KP和心钠素(ANP)含量。结果:高血压患者血浆KP、ANP水平与对照组比较无显著差异。但是,KP与ANP的摩尔比显著低于对照组(P＜0.05),SHR血浆KP、ANP水平显著高于对照组(WKY)(P＜0.01和P＜0.05),KP/ANP摩尔比则显著低于WKY(P＜0.01)。SHR心房KP含量高于心室(P＜0.05),但与对照组WKY比较无显著差异。结论:KP含量及KP与ANP的比例关系的改变,在老年原发性高血压发病中起着一定的作用。     

妊高征脐血管内皮细胞损伤与SOD和LPO的变化及意义

目的探讨脐血管内皮细胞损伤、血清超氧化物歧化酶(SOD)和过氧化脂质(LPO)在妊高征发病中的作用。方法随机选择妊高征患者33例(PIH组)、正常晚期妊娠妇女33例(NLP组),分别采用免疫组织化学法、放射免疫法和荧光测定法检测脐血管内皮细胞损伤程度、血清SOD和LPO水平。结果妊高征组脐动脉内皮细胞损伤较正常妊娠组加重,而且与病情程度有关(P<0.05;P<0.01);其血清SOD较正常妊娠组显著减少(P<0.001),而LPO较正常妊娠组显著增加(P<0.001),SOD/LPO比值较正常妊娠组明显降低(P<0.001)。结论妊娠期血管内皮细胞损伤加重以及机体氧化和抗氧化平衡失调可能与妊高征的发病过程有关。     

Factors of the extrinsic pathway of blood coagulation in fetal placental macrophages

Term human placentae were examined to identify and localize the factors contributing to extravascular fibrin formation. In addition to blood vessels, components of the extrinsic coagulation cascade were also demonstrated in intracellular localization. These cells in double and treble labeling systems expressed macrophage marker antigens, recognized by DAKO antimacrophage, RFD7, Amersham antimacrophage, and KiM7 monoclonal antibodies and showed positivity for alpha-naphthyl-acetate-esterase (ANAE). The fact that factors of the extrinsic coagulation system can be demonstrated in fetal macrophages of the chorionic stroma suggests that their role is not restricted to cellular defense and phagocytosis, but they may be involved in extravascular intraplacental fibrin formation as well.     

Protection against autoimmune disease by bacterial agents. II. PPD and pertussis toxin as proteins active in protecting mice against experimental autoimmune encephalomyelitis

Bordetella pertussis and Mycobacterium tuberculosis, routinely used to promote the development of autoimmune disease, were recently reported to also be effective in inducing protection against an autoimmune disease. Thus, we previously demonstrated that SJL/J and (SJL/J x BALB/c)F₁ mice that are genetically susceptible to experimental autoimmune encephalomyelitis (EAE) become highly refractory to the induction of the disease following their exposure to B. pertussis and M. tuberculosis. In the present study, the pertussis toxin (PT) from B. pertussis and the purified protein derivative (PPD) of M. tuberculosis, were found to be sufficient to fully protect against EAE and thus may be the major bacterial components responsible for conferring protection. The 65-kDa heat-shock protein played only a marginal role in the protection against EAE induced by these bacteria. Both PT and PPD were protective when given before, but not after, the encephalitogenic challenge, and minute amounts (5–50 ng) emulsified in oil were sufficient to confer long-lasting resistance to EAE. The effect of PT or PPD on EAE differed from that of mitogens or bacterial superantigens, suggesting that their protection ability was not attributable merely to mitogenic or superantigenic properties. The mechanism of protection is not yet clear. Preliminary studies revealed a complex mechanism of protection whereby PPD and PT may operate differently. Thus, only PPD-induced, but not PT-induced, protection was transferrable by CD4⁺ T lymphocytes bearing an αγ Tcell antigen receptor. Neither PT nor PPD had a protective effect on EAE mediated by preformed pathogenic T lymphocytes and it is most likely that they exert their protection by affecting the development of such T lymphocytes. How bacteria such as B. pertussis and M. tuberculosis can either enhance the development of an autoimmune disease or protect against the disease is not yet clear. However, identifying PT and PPD as the bacterial components active in protection may allow a better understanding of the modulatory effects of bacteria and point to the potential use of such bacterial products in immunomodulation of autoimmune diseases.