脑血管腔内支架置入治疗症状性脑动脉狭窄20例

背景:关于脑血管支架置入后局部机械性血管壁损伤后发生血管内再狭窄研究中涉及的安全性、病理生理机制及临床疗效尚无确切的结论.目的:探讨脑血管腔内支架置入治疗症状性脑动脉狭窄的安全性、近期临床疗效.方法:对20例症状性脑动脉狭窄患者行脑血管腔内支架置入治疗,狭窄病变22处,位于大脑中动脉6处、颈内动脉6处、椎动脉4处、基底动脉3处,3例为椎-基底动脉狭窄;狭窄长度为3～10 mm,平均为7 mm,其中6处狭窄长度超过10 mm.行自膨式及球囊膨胀式支架置入,使用脑保护装置保护伞12例.结果与结论:20例患者22枚支架均1次放置成功,无一例发生严重并发症,置入后即刻血管造影结果显示,病变段动脉残余狭窄程度小于20%,与治疗前相比较,管腔狭窄明显改善.同时再造影的实质期可见脑组织血流灌注得到改善,临床症状全部得到改善.置入后临床随访6-24个月,20例未再有脑缺血发作,数字减影血管造影随访12～24个月7例,1例出现支架内内膜轻度增生,未引起临床症状.经颅超声多普勒随访结果示狭窄部位血流通畅,支架内未见内膜过度增生,无主要分支血管的闭塞.结果说明脑血管腔内支架置入治疗症状性颅内动脉狭窄安全,近期疗效明显,其长期疗效还需进一步随访观察.     

Human cytotrophoblasts adopt a vascular phenotype as they differentiate. A strategy for successful endovascular invasion?

Establishment of the human placenta requires that fetal cytotrophoblast stem cells in anchoring chorionic villi become invasive. These cytotrophoblasts aggregate into cell columns and invade both the uterine interstitium and vasculature, anchoring the fetus to the mother and establishing blood flow to the placenta. Cytotrophoblasts colonizing spiral arterioles replace maternal endothelium as far as the first third of the myometrium. We show here that differentiating cytotrophoblasts transform their adhesion receptor phenotype so as to resemble the endothelial cells they replace. Cytotrophoblasts in cell columns show reduced E-cadherin staining and express VE-(endothelial) cadherin, platelet-endothelial adhesion molecule-1, vascular endothelial adhesion molecule-1, and alpha-4-integrins. Cytotrophoblasts in the uterine interstitium and maternal vasculature continue to express these receptors, and, like endothelial cells during angiogenesis, also stain for alphaVbeta3. In functional studies, alphaVbeta3 and VE-cadherin enhance, while E-cadherin restrains, cytotrophoblast invasiveness. Cytotrophoblasts expressing alpha4 integrins bound immobilized VCAM-1 in vitro, suggesting that this receptor-pair could mediate cytotrophoblast-endothelium or cytotrophoblast-cytotrophoblast interactions in vivo, during endovascular invasion. In the pregnancy disorder preeclampsia, in which endovascular invasion remains superficial, cytotrophoblasts fail to express most of these endothelial markers (Zhou et al., 1997. J. Clin. Invest. 99:2152-2164.), suggesting that this adhesion phenotype switch is required for successful endovascular invasion and normal placentation.     

Mesenchymal stem/stromal cells (MSCs): role as guardians of inflammation

Recent observations have demonstrated that one of the functions of mesenchymal stem/stromal cells (MSCs) is to serve as guardians against excessive inflammatory responses. One mode of action of the cells is that they are activated to express the interleukin (IL)-1 receptor antagonist. A second mode of action is to create a negative feedback loop in which tumor necrosis factor-α (TNF-α) and other proinflammatory cytokines from resident macrophages activate MSCs to secrete the multifunctional anti-inflammatory protein TNF-α stimulated gene/protein 6 (TSG-6). The TSG-6 then reduces nuclear factor-κB (NF-κB) signaling in the resident macrophages and thereby modulates the cascade of proinflammatory cytokines. A third mode of action is to create a second negative feedback loop whereby lipopolysaccharide, TNF-α, nitric oxide, and perhaps other damage-associated molecular patterns (DAMPs) from injured tissues and macrophages activate MSCs to secrete prostaglandin E(2) (PGE(2)). The PGE(2) converts macrophages to the phenotype that secretes IL-10. There are also suggestions that MSCs may produce anti-inflammatory effects through additional modes of action including activation to express the antireactive oxygen species protein stanniocalcin-1.     

慢病毒介导的血红素加氧酶-1对脂肪干细胞在低氧无血清条件下的保护作用

目的探讨慢病毒介导的血红素加氧酶-1(HO-1)对脂肪干细胞(ADSCs)在低氧无血清的条件下的保护作用。方法分离培养SD大鼠ADSCs,取第三代ADSCs分为五组:对照组;单纯低氧无血清组;空载体病毒组;HO-1组;HO-1+ZnPP组。采用DAPI染色检测各组细胞凋亡率;Western blot法检测各组HO-1、Cleaved-Caspase-3的表达量。结果携带HO-1基因的慢病毒转染ADSCs(HO-1组)可明显增加ADSCs中HO-1的表达;ADSCs在缺氧状态下发生大量凋亡,其凋亡率为(27.29±1.18)%,转空载体的细胞凋亡率达(27.47±1.35)%,而转HO-1基因的ADSCs的凋亡率仅为(12.00±1.18)%,HO-1+ZnPP组:凋亡率(25.52±2.98)%。与对照组相比,低氧无血清组与空载体病毒组ADSCs的Cleaved-Caspase-3的表达有显著升高(P<0.05);HO-1组Cleaved-Caspase-3的表达与低氧无血清组与空载体病毒组相比有明显下降(P<0.05);而HO-1+ZnPP组Cleaved-Caspase-3的表达又明显高于HO-1组(P<0.05)。结论提高ADSCs中HO-1蛋白的表达可以通过降低凋亡效应因子Caspase-3的活性显著降低ADSCs在低氧无血清条件下的凋亡率。     

Plasmid-Mediated Resistance to Thrombin-Induced Platelet Microbicidal Protein in Staphylococci: Role of the qacA Locus

Thrombin-induced platelet microbicidal protein 1 (tPMP-1) is a small, cationic peptide released from rabbit platelets following thrombin stimulation. In vitro resistance to this peptide among strains of Staphylococcus aureus correlates with the survival advantage of such strains at sites of endothelial damage in humans as well as in experimental endovascular infections. The mechanisms involved in the phenotypic resistance of S. aureus to tPMP-1 are not fully delineated. The plasmid-encoded staphylococcal gene qacA mediates multidrug resistance to multiple organic cations via a proton motive force-dependent efflux pump. We studied whether the qacA gene might also confer resistance to cationic tPMP-1. Staphylococcal plasmids encoding qacA were found to confer resistance to tPMP-1 in an otherwise susceptible parental strain. Deletions which removed the region containing the qacA gene in the S. aureus multiresistance plasmid pSK1 abolished tPMP-1 resistance. Resistance to tPMP-1 in the qacA-bearing strains was inoculum independent but peptide concentration dependent, with the level of resistance decreasing at higher peptide concentrations for a given inoculum. There was no apparent cross-resistance in qacA-bearing strains to other endogenous cationic antimicrobial peptides which are structurally distinct from tPMP-1, including human neutrophil defensin 1, protamine, or the staphylococcal lantibiotics pep5 and nisin. These data demonstrate that the staphylococcal multidrug resistance gene qacA also mediates in vitro resistance to cationic tPMP-1.     

间歇缺氧及睡眠剥夺大鼠血管内皮细胞相关指标的变化

背景：血管内皮功能损坏是睡眠呼吸暂停的病理基础。目的：观察间歇缺氧、睡眠剥夺对SD大鼠有创动脉收缩压及血浆一氧化氮、内皮素、降钙素基因相关肽水平的影响。方法：将3月龄雄性SD大鼠16只随机等分为2组,模型组大鼠每天置入睡眠剥夺合并间歇性缺氧条件10h（22：00-08：00）,单纯睡眠剥夺条件12h（08：00-20：00）,剩余时间置大鼠笼饲养。对照组无睡眠剥夺、无缺氧条件饲养。结果与结论：造模8周后,与对照组比较,模型组大鼠有创动脉压明显升高（P〈0.01）,血浆一氧化氮、降钙素基因相关肽水平显著降低（P〈0.01）,血浆内皮素水平显著升高（P〈0.01）。说明间歇性缺氧、睡眠剥夺可以引起SD大鼠血压增高,血管内皮功能受损。     

Hyperoxic lung injury: biochemical, cellular, and morphologic characterization in the mouse

Controversy exists over the mechanism by which oxygen produces lung damage. This study was designed to characterize the biochemical, cellular, and morphologic responses of mice exposed to 100% oxygen and thereby provide the basis for investigating the mechanisms producing the lung damage as well as for evaluating treatment strategies. After 1 day of exposure, plasma lactate dehydrogenase (LDH) activity and LDH isoenzyme 1, 2, and 3 concentration increased, whereas the level of isoenzyme 1 recovered from the lung, heart, and kidney decreased. On day 2, the level of these plasma isoenzymes increased further, whereas isoenzyme 1 concentration remained decreased only in the lung. In addition, the number of cells obtained by bronchoalveolar lavage (BAL) doubled, and electron microscopy revealed type 1 cell and endothelial cell damage. On day 3, the amount of BAL protein doubled, BAL angiotensin-converting enzyme (ACE) activity increased sevenfold, plasma ACE activity decreased 39%, and electron microscopy revealed extensive cell damage. On day 4, the injury was much worse and was associated with a 10-fold increase in the number of BAL cells, nearly all of which were polymorphonuclear leukocytes (PMNs). On day 5, greater than 65% of the mice were dead. The data suggest that in mice (1) an increase in plasma LDH activity and a shift in its isoenzyme pattern are sensitive markers of hyperoxic lung damage, (2) the initial injury produced by oxygen is independent of PMNs, and (3) the damage to alveolar epithelial cells and endothelial cells is severe and occurs at the same time. Studies using this well-characterized model can now be designed to further define the mechanisms that initiate hyperoxic lung damage and that contribute to its progression.     

Interresponse time changes as a function of water deprivation and amphetamine.

Drug effects on operant behavior are often characterized by their effects on rate of responding, usually expressed as the number of responses per unit of time. The time between two consecutive responses constitutes an interresponse time (IRT), and this measure has been used also to characterize the effects of drugs on operant behavior. IRTs which occur during a session can be classified on a statistical basis as: 1) short-IRT, an IRT(s) of short duratio generated by high-frequency responses; 2) pause, an IRT of long duratio generated by low-frequency responses; and 3) post-reinforcement pause, an IRT which immediately follows reinforcement. This investigation used three schedules of water reinforcement (fixed-ratio 20, fixed-interval 90-seconds and variable-interval 20-seconds) to examine how these IRT classes are influenced by changes in water deprivation conditions or amphetamine administration. Base-line IRT distributions depended upon the schedule of reinforcement. Changes induced by doses of amphetamine or alterations in level of water deprivation were compared and contrasted. Short-IRTs that characterized fixed-ratio 20 performance were resistant to change with increasing doses of amphetamine, but were increased in duration with decreasing water deprivation. Animals responding on a fixed-interval 90-second schedule showed a decreased postreinforcement pause after amphetamine, but an increased postreinforcement pause after access to water. An additional experiment studied the combined effects of presession water consumption and d-amphetamine administration on variable interval performances. Making water available before the session lowered the amphetamine dose-response curve along the vertical axis, suggesting that amphetamine did not mimic satiation. In most cases the effect of amphetamine and changing levels of water deprivation were dissimilar in their effects on IRT distributions, suggesting that amphetamine does not exert its major action on behavior through its adipsic effect.     

Effect of hydroxyethyl starch on vascular leak syndrome and neutrophil accumulation during hypoxia

OBJECTIVE: Several studies have suggested that intravenous hydroxyethyl starch treatment may dampen acute inflammatory responses. It is well documented that limited oxygen delivery to tissues (hypoxia) is common in acute inflammation, and numerous parallels exist between acute responses to hypoxia and to inflammation, including the observation that both are associated with increased vascular leakage and neutrophil infiltration of tissues. Therefore, we compared functional influences of hydroxyethyl starch on normoxic or posthypoxic endothelia. DESIGN: Laboratory study. SETTING: University hospital. SUBJECTS: Cultured human microvascular endothelial cells and mice (C57BL/6/129 svj). INTERVENTIONS: We measured functional influences of hydroxyethyl starch on normoxic or posthypoxic endothelia. MEASUREMENTS AND MAIN RESULTS: Studies to assess endothelial barrier function in vitro indicated that the addition of hydroxyethyl starch promotes endothelial barrier in a dose-dependent fashion and hydroxyethyl starch-barrier effects are increased following endothelial hypoxia exposure (human microvascular endothelial cells, 48 hrs, 2% oxygen). Treatment of human microvascular endothelial cells with hydroxyethyl starch resulted in a dose-dependent increase in 157-phosphorylated vasodilator-stimulated phosphoprotein, a protein responsible for controlling the geometry of actin-filaments. Neutrophil adhesion was decreased in the presence of physiologically relevant concentrations of hydroxyethyl starch in vitro, particularly after endothelial hypoxia exposure. Using a murine model of normobaric hypoxia, increases in vascular leakage and pulmonary edema associated with hypoxia exposure (4 hrs at 8% oxygen) were decreased in animals treated with intravenous hydroxyethyl starch. Increases of tissue neutrophil accumulation following hypoxia exposure were dampened in hydroxyethyl starch-treated mice. CONCLUSIONS: Taken together, these results indicate that hypoxia-induced increases in vascular leakage and acute inflammation are attenuated by hydroxyethyl starch treatment.     

Antitumor actions of ruthenium(III)-based nitric oxide scavengers and nitric oxide synthase inhibitors

The role of endogenous nitric oxide (NO) in the growth and vascularization of a rat carcinosarcoma (P22) has been investigated. Tumor-bearing animals were treated with (i) nitric oxide synthase (NOS) inhibitors, administered via the drinking water, including N(G)-nitro-l-arginine methyl ester (L-NAME), a nonisoform-selective inhibitor, and 2 others that target the inducible (NOS II) enzyme preferentially, namely 1-amino-2-hydroxyguanidine or N-[3-(aminomethyl)benzyl]acetamidine hydrochloride; or (ii) daily injections (intraperitoneally) of 2 Ru(III) polyaminocarboxylates, AMD6221 and AMD6245, both of which are effective NO scavengers. L-NAME, AMD6221, and AMD6245 reduced tumor growth by approximately 60% to 75% of control rates. Tumor sections stained with abs to CD-31/platelet endothelial cell adhesion molecule-1 or NOS III showed that this was associated with a marked reduction (60%-77%) of tumor microvascular densitiy (MVD). Tumors resumed growing promptly when treatment was discontinued, accompanied by partial or complete restoration of MVDs. In contrast, NOS-II selective inhibitors had no effect on tumor growth or vascularization, indicating that both responses require complete blockade of NO production. The results corroborate the view that endogenous NO facilitates tumor development. We suggest that NO deprivation causes tumor feeder vessels to constrict, reducing tumor blood flow. The delivery of oxygen and essential nutrients to the developing tumor is impaired as a consequence, hampering further growth. Normalizing NO levels by withholding treatment causes tumor feeder vessels to dilate, increasing tumor perfusion and reestablishing conditions that allow tumors to begin growing again.     

Disparate mechanisms for hypoxic cell injury in different nephron segments. Studies in the isolated perfused rat kidney.

Hypoxic injury was evaluated morphologically in the proximal tubule and in the medullary thick ascending limb of isolated rat kidneys perfused for 90 min without O2 or with various metabolic inhibitors. Inhibition of mitochondrial respiration (with rotenone, antimycin, oligomycin) or of intermediary metabolism (with monofluoroacetate, malonate, 2-deoxyglucose) caused reduction in renal oxygen consumption, renal function, and ATP content comparable with those elicited by oxygen deprivation. Metabolic inhibition produced hypoxiclike injury in the first portions of the proximal tubule, S1 and S2 ("clubbing" of microvilli, mitochondrial swelling), and the extent of damage was correlated with the degree of ATP depletion. In the third portion of the proximal tubule, S3, hypoxiclike damage (cytoplasmic edema or fragmentation) occurred most consistently when both aerobic and anaerobic metabolism were inhibited simultaneously. In the medullary thick ascending limb, none of the metabolic or mitochondrial inhibitors used could reproduce the injury of oxygen deprivation. Thus, the proximal tubule and the thick ascending limb have markedly different responses to cellular energy depletion, suggesting disparate mechanisms for hypoxic injury along the nephron.     

What have anatomic and pathologic studies taught us about acute lung injury and acute respiratory distress syndrome?

PURPOSE OF REVIEW: Acute lung injury and acute respiratory distress syndrome are defined as morphologic and functional manifestations of pulmonary injury of various causes. Acute lung injury and acute respiratory distress syndrome may result from direct effects on epithelial lung cells or from indirect effects on endothelial lung cells, reflecting lung involvement as part of a more distant systemic inflammatory response. This review addresses anatomic/pathologic differences between acute lung injury and acute respiratory distress syndrome lungs. RECENT FINDINGS: It is well established that acute lung injury and acute respiratory distress syndrome are characterized by local and intense inflammatory responses, with accumulation of several types of cells and soluble mediators. There are parallel anti-inflammatory response and lung remodeling, with deposition of collagen. Patient outcome will depend on resolution of the initial event and on the balance between the inflammatory and remodeling responses. Several trials have attempted to modify both responses, but all have yielded negative results. SUMMARY: An appreciation of the acute respiratory distress syndrome must take into account anatomic/pathologic characteristics, which depend upon the initial cause. Consideration of each pathologic mechanism will permit more precise clinical management and probably improved outcomes.     

Hydrogen peroxide stimulates the synthesis of platelet-activating factor by endothelium and induces endothelial cell-dependent neutrophil adhesion.

Oxidant-induced damage to the intima of pulmonary and systemic vessels is thought to be an important mechanism of injury in a variety of syndromes of vascular damage. Hydrogen peroxide (H2O2) is an active oxygen metabolite that may induce intimal injury by cytolytic attack or by inducing biochemical and functional alterations in the endothelial cells (EC); however, mechanisms involved in noncytolytic perturbation of EC are largely unknown. We found that H2O2 stimulated the synthesis of platelet-activating factor (PAF) by primary cultures of bovine pulmonary artery endothelium (BPAEC) and by human umbilical vein endothelium (HUVEC). In each cell type the incorporation of [3H]acetate into [3H-acetyl]PAF was concentration- and time-dependent and was temporally dissociated from severe plasma membrane disruption and cytolytic cell injury; the newly synthesized PAF remained associated with the EC. H2O2 caused permeabilization of EC to 45Ca2+ and an increase in intracellular Ca2+, suggesting that a transmembrane Ca2+ flux is the signal that initiates PAF synthesis. H2O2 also induced the endothelial cell-dependent adhesion of neutrophils to HUVEC monolayers. This response was rapid, with an onset within minutes and a subsequent time course that paralleled the time course of PAF accumulation, and was dependent on extracellular Ca2+ but not on de novo protein synthesis. These studies demonstrate that H2O2 can induce two rapid activation responses of endothelium, PAF synthesis and EC-dependent neutrophil adhesion, events that may be important in physiologic and pathologic inflammation.     

Endothelium-derived microparticles inhibit human cardiac valve endothelial cell function

Elevated numbers of endothelium-derived microparticles (EMPs) in the circulation are found in a variety of critical illnesses. EMPs have been associated with vascular dysfunction, including thrombotic complications and loss of normal vascular reactivity, common responses associated with cardiac valve injury. However, the exact mechanisms of this dysfunction and the potential impact on cardiac endothelium are unknown. We hypothesize that pathologic levels of circulating EMPs negatively regulate proliferation and migration of valvular endothelial cells (ECs), leading to downstream endothelial dysfunction. EMPs were generated from plasminogen activation inhibitor 1-stimulated human umbilical vein endothelial cells (HUVECs). Human mitral valve endothelial cells (HMVECs) were isolated and characterized by platelet endothelial cell-derived adhesion molecule-1 (PECAM-1, or CD31) and von Willebrand factor immunocytochemistry. HMVECs were treated with increasing EMP doses, and then, the effects of EMPs on growth factor-induced proliferation and migration were tested. Proliferation was assessed by H-thymidine incorporation. EC migration was assayed by photographing microtubules of HMVECs and HUVECs in fibrin gel incubated with EMPs +/- growth factors for 48 h. The EMP effects on non-valve HUVECs were tested in parallel. EMPs inhibited HMVEC proliferation at high doses but stimulated HUVEC proliferation at all doses. In HMVECs, EMPs inhibited basic fibroblast growth factor- and vascular endothelial growth factor-induced proliferation and migration. Taken together, these data suggest EMPs regulate valvular EC proliferation in a dose-dependent manner and, furthermore, modulate growth factor signaling in ECs. These results implicate EMPs as a possible source of downstream EC dysfunction in disease states. EMPs may play a role in valvular leaflet injury in human disease by inhibiting normal growth and repair of endothelium.     

Mutation in pre-mRNA adenosine deaminase markedly attenuates neuronal tolerance to O2 deprivation in Drosophila melanogaster

O2 deprivation can produce many devastating clinical conditions such as myocardial infarct and stroke. The molecular mechanisms underlying the inherent tissue susceptibility or tolerance to O2 lack are, however, not well defined. Since the fruit fly, Drosophila melanogaster, is extraordinarily tolerant to O2 deprivation, we have performed a genetic screen in the Drosophila to search for loss-of-function mutants that are sensitive to low O2. Here we report on the genetic and molecular characterization of one of the genes identified from this screen, named hypnos-2. This gene encodes a Drosophila pre-mRNA adenosine deaminase (dADAR) and is expressed almost exclusively in the adult central nervous system. Disruption of the dADAR gene results in totally unedited sodium (Para), calcium (Dmca1A), and chloride (DrosGluCl-alpha) channels, a very prolonged recovery from anoxic stupor, a vulnerability to heat shock and increased O2 demands, and neuronal degeneration in aged flies. These data clearly demonstrate that, through the editing of ion channels as targets, dADAR, for which there are mammalian homologues, is essential for adaptation to altered environmental stresses such as O2 deprivation and for the prevention of premature neuronal degeneration.     

Development of cardiovascular bypass grafts: endothelialization and applications of nanotechnology

There is a critical clinical need for small-diameter bypass grafts, with applications involved in the coronary artery and lower limb. Commercially available materials give rise to unfavorable responses when in contact with blood and subjected to low-flow hemodynamics and, thus, are nonideal as small-diameter bypass grafts. Optimizing the mechanical properties to match both the native artery and the graft surfaces has received keen attention. Endothelialization of bypass grafts is considered a protective mechanism where the biochemicals produced from endothelial cells exert a range of favorable responses, including antithrombotic, noninflammatory responses and inhibition of intimal hyperplasia. In situ endothelialization is most desirable. Nanotechnology approaches facilitate all aspects of endothelialization, including endothelial progenitor cell mobilization, migration, adhesion, proliferation and differentiation. 'Surface nanoarchitecturing mechanisms', which mimic the natural extracellular matrix to optimize endothelial progenitor cell interaction and controlled delivery of various factors in the form of nanoparticles, which can be combined with gene therapy, are of keen interest. This article discusses the development of bypass grafts, focusing on the optimization of the biological properties of mechanically suitable grafts.