Antigenic heterogeneity of vascular endothelium.

The antigenic status of vascular endothelium from different sites of the normal adult and fetal human cardiovascular system was investigated. Tissues included aorta (n = 9), pulmonary artery (n = 8), coronary artery (n = 6), ventricle/atrium (n = greater than 10), lymph node (n = 2), fetal whole heart (n = 3), and umbilical cord (n = 7). Frozen sections were studied using monoclonal antibodies recognizing endothelial markers (EN4, vWf, Pal-E, and 44G4), vascular adhesion molecules (ICAM-1, ELAM, VCAM, and PECAM), the monocyte/endothelial marker (OKM5), and major histocompatibility complex (MHC) molecules (class I and class II). Results demonstrate that capillary endothelium is phenotypically different from endothelial cells (EC) lining large vessels. Capillary EC strongly express MHC classes I and II, ICAM, and OKM5, which are variably weak to undetectable on large vessels. In contrast, the large vessels strongly express vWf and appear to constitutively express ELAM-1. This suggests that the capillary EC may be more efficient at antigen presentation or more susceptible to immune attack in vivo. Interestingly, normal coronary arteries, unlike all other large vessels, express MHC class II and VCAM molecules. Future studies should concentrate on comparative functional studies between capillary, coronary, and large vessel EC.     

Novel therapies targeting vascular endothelium.

Endothelial dysfunction has been identified as a major mechanism involved in all the stages of atherogenesis. Evaluation of endothelial function seems to have a predictive role in humans, and therapeutic interventions improving nitric oxide bioavailability in the vasculature may improve the long-term outcome in healthy individuals, high-risk subjects, or patients with advanced atherosclerosis. Several therapeutic strategies are now available, targeting both the synthesis and oxidative inactivation of nitric oxide (NO) in human vasculature. Statins seem to be currently the most powerful category of these agents, improving endothelial function and decreasing cardiovascular risk after long-term administration. Other cardiovascular agents improving endothelial function in humans are angiotensin-converting enzyme inhibitors/angiotensin receptors blockers, which increase NO bioavailability by modifying the rennin-angiotensin-aldosterone system. Newer therapeutic approaches targeting endothelial dysfunction in specific disease states include insulin sensitizers, L-arginine (the substrate for endothelial NO synthase [eNOS]) as well as substances that target eNOS "coupling," such as folates or tetrahydrobiopterin. Although there are a variety of strategies to improve NO bioavailability in human endothelium, it is still unclear whether they have any direct benefit at a clinical level.     

Altered vascular endothelium integrin expression in psoriasis.

Considerable evidence indicates that microvascular changes observed in psoriasis are a result of vascular proliferation. A critical step in the sequence of events leading to neovascularization involves interactions between endothelial cells and extracellular matrix proteins mediated in part by the integrin family of adhesion molecules. A number of endothelial integrins have been shown to participate in neovascularization, including members of the beta 1, beta 3, and beta 4 subfamilies. To investigate the role of these integrins in psoriasis, specimens of lesional and nonlesional skin were taken from 10 patients with active, untreated plaque disease. Vascular endothelium was labeled with monoclonal antibodies specific for alpha 2, alpha 5, alpha 6, beta 1, av beta 3, and beta 4 integrins. The use of image analysis permitted quantification of immunoperoxidase staining and comparison of endothelial labeling in lesional and nonlesional skin. There was a significant increase in endothelial staining of av beta 3 integrin in lesional compared with nonlesional skin, both in superficial and deep vasculature. In contrast, there was a significant decrease in endothelial beta 4 staining in lesional compared with nonlesional superficial dermal vessels, alpha 2, alpha 5, alpha 6, and beta 1 staining showed no significant difference between the two groups. These results demonstrate an important role of av beta 3 and beta 4 integrins in the microvascular changes of psoriatic lesions.     

Effect of cyngal on gastric secretion in rats

The effect of the gallate of the alkaloid cynoglossophine-heliosupine (cyngal), isolated from the plantCynoglossum officinale L., of the Boraginaceae family, on gastric secretion was studied in rats. Cyngal was shown to stimulate gastric secretion in rats starting from a dose of 0.25 mg/kg. This action is explained by the ability of the alkaloid to liberate histamine from labile depots.Department of Pharmacology, Leningrad Pharmaceutical Chemical Institute. Laboratory of Experimental Pharmacology, Research Institute of Experimental Medicine, Academy of Medical Sciences of the USSR, Leningrad. (Presented by Academician of the Academy of Medical Sciences of the USSR S. V. Anichkov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 12, pp. 679–682, December, 1977.     

Collagen cross-link synthesis in cultured vascular endothelium.

Cultured vascular endothelium secretes the enzyme lysyl oxidase which cross-links both collagen and elastin. The major reducible cross-link synthesized by cultured human umbilical arterial and venous endothelium is dihydroxylysinonorleucine (di-OH-LNL). Treatment of the cultures with the lathyrogen beta-aminopropionitrile (BAPN), which inhibits lysyl oxidase, inhibited synthesis of this cross-link. Cultured porcine aortic endothelium synthesized three major reducible lysine-derived cross-links: dihydroxylysinonorleucine (di-OH-LNL), hydroxylysinonorleucine (OH-LNL) and lysinonorleucine (LNL); BAPN also inhibited synthesis of these three cross-links. Earlier in-vivo observations on BAPN-treated chick embryos had shown a 20% increase in the hydration of cartilage and other tissues; the likeliest explanation was that cross-link disruption permitted the proteoglycans in cartilage to express their hydrophilic nature when freed of their collagenous network. Capillary basement membrane contains laminin, proteoglycan and type IV collagen. Following the finding of oedema in lathyritic cartilage, we would propose that agents which disrupt collagen cross-links in cultured vascular endothelium, damaging capillary basement membrane, be considered as one possible mechanism in the pathogenesis of oedema.     

Ultrastructural damage in vascular endothelium in rats treated with paclitaxel and doxorubicin

Endothelium is the first physiological barrier between blood and tissues and can be injured by physical or chemical stress, particularly by the drugs used in the cancer therapy. Paclitaxel and doxorubicin are frequently used anticancer drugs and their cardiac side effects are well observed in clinical setting. Their side effects on the endothelium are still not clear enough. There are few investigations assessing the damages elicited by the combination use of chemotherapy agents in animal experimental models. The purpose of this study was to examine and compare the side effects of doxorubicin and paclitaxel on endothelium in vivo. The drugs were administered weekly to rats via intraperitoneal injections singly or in combinations. Lastly, aorta endothelium was examined. The most familiar parts of the aorta endothelium are the nucleus, free ribosomes, Weibel-Palada granules, plasmalemmal vesicles, and clear basement membrane. Examination of the endothelium and the related structures revealed some clear degenerative findings. Notably, administration of a paclitaxel and doxorubicin combinations caused the most dramatic change in ultrastructure, which may disrupt many functions of the endothelium.     

Effect of Ebselen on polymorphonuclear leukocyte adhesion to and migration through cytokine-activated vascular endothelium.

Ebselen (PZ51, 2-Phenyl-1, 2-Benzoisoselenazol-3-(2H)-one) is a selinyl organic compound with anti-inflammatory properties. Some of its pharmacological effects are thought to result from its peroxidase activity. Here we examined the effects of Ebselen on polymorphonuclear leukocyte (PMNL) adhesion to umbilical vein endothelium and transendothelial migration in a modified Boyden chamber in which both PMNL-dependent and endothelial-dependent (IL-1, TNF alpha) PMNL adhesion and migration can be measured. Ebselen was found to dose dependently inhibit the adhesion of PMNL to IL-1 activated endothelium and to inhibit transendothelial PMNL migration induced by IL-1 alpha, and TNF alpha with an IC50 value of 28 microM. Transendothelial migration induced by the PMNL chemotactic agents C5adesArg and N-formyl-norleu-leu-phe was also inhibited at slightly higher concentrations. The effect of Ebselen was not on endothelial cell activation but on PMNL activation for adhesion and migration. This effect on PMNL was irreversible for the duration of the assay period (75 min). The results suggest that the anti-inflammatory activity of Ebselen may, in part, be due to direct inhibition of PMNL adhesion to vascular endothelium and transendothelial migration in response to a variety of inflammatory mediators.     

En face organ culture of vascular endothelium.

A simple technique is described for maintaining in organ culture segments of blood vessel in such a way that the endothelium can be studied en face. The behaviour of such cultures throws further light on the interaction between endothelium and intravascular clotting.     

Effect of adrenergic blockade on gastric secretion altered by catecholamines in rats.

The effect of adrenergic blockade on gastric secretion altered by catecholamines was studied for 4 hr after injection in rats with chronic gastric fistulas. The alpha-adrenergic blockers phenoxybenzamine and phentolamine significantly inhibited the basal secretion of HCl and pepsin. Blockade of the beta-adrenergic receptors with propranolol did not change this secretion. Practolol in small doses slightly increased and in larger doses inhibited HCl out-put. Of the catecholamines, adrenaline and dopamine most markedly reduced HCl and pepsin secretion, while noradrenaline and isoprenaline had a weaker effect. Neither alpha- nor beta-adrenergic blockers prevented the inhibitory action of the catecholamines employed, but intensified the depression of the gastric secretion provoked by them. Adrenergic blockers inhibited secretion after catecholamines as well as basal secretion. This indicates that these two antagonistic groups of compounds act independently on the mechanism controlling gastric secretion. It is unlikely that this takes place indirectly through changes in the blood supply of the gastric mucosa.     

罗格列酮减轻2型糖尿病大鼠血管内皮功能受损

目的观察2型糖尿病大鼠血清内皮素(ET)和一氧化氮(NO)水平、主动脉病理变化、在主动脉的内皮型一氧化氮合酶(e NOS)蛋白和mRNA表达及罗格列酮的干预作用。方法将大鼠随机分为对照组、高脂组、糖尿病组和罗格列酮组,每组20只。制备2型糖尿病大鼠模型后,罗格列酮治疗组4 mg/kg·d灌胃给药,于治疗6周和12周时检测血糖、ET、NO及光镜下主动脉的病理变化;用Western blot和real-time PCR检测主动脉的e NOS蛋白和mRNA表达。结果 1)与对照组比较,高脂组、糖尿病组及罗格列酮治疗组ET升高,NO降低(P0.01)。12周时糖尿病组较高脂组和罗格列酮治疗组ET升高,NO降低(P0.05)。糖尿病组NO水平在12周时比6周时明显下降(P0.05)。2)12周时高脂组、糖尿病组和罗格列酮组大鼠主动脉出现不同程度病理改变。3)6周和12周时,与对照组比较,高脂组、糖尿病组和罗格列酮组主动脉e NOS的蛋白和mRNA表达下调(P0.01);糖尿病组较罗格列酮组主动脉e NOS的蛋白表达下调(P0.01)。结论罗格列酮可以缓解糖尿病组大鼠血管内皮功能受损。     

Immunobiology of human vascular endothelium

The author’s laboratory studies interactions between human T lymphocytes and vascular endothelial cells (EC). Our work is organized around three hypotheses. First, we propose that vascular EC can initiate secondary (i.e., recall) immune reactions by presenting antigenic peptide-major histocompatibility complex (MHC) complexes to those circulating memory T cells whose cognate antigen is locally present within a peripheral tissue, e.g., as a consequence of infection or allogeneic transplantation. In this way, EC can increase the efficiency of immune surveillance. Second, we propose that T cell signals, both secreted (e.g., cytokines) and contact-dependent (e.g., CD40 ligand), activate new gene expression in EC that induce the capacity to perform new effector functions, such as leukocyte recruitment and activation or initiation of intravascular coagulation. In this way, EC can particpate as effector cells for cell-mediated immune reactions. Third, we propose that EC are major targets of immune-mediated injury. Consequently, increasing resistance of endothelium to immune effector mechanisms may protect tissues from damage, e.g., in allograft rejection. These three hypotheses are explored through in vitro experiments, through analyses of human tissue specimens, and through in vivo studies employing novel human-mouse chimeric animals.     

高血糖症对大鼠血管内皮舒张功能的影响

目的：复制高血糖症动物模型，研究高糖对大鼠血管内皮舒张功能的影响及其机制。方法：采用血管功能检测、组织培养及放射免疫分析方法。结果：①高血糖组血管乙酰胆硷依赖性血管舒张反应明显降低（Ｐ＜００１）；②高血糖组血浆ＮＯ－２含量、主动脉一氧化氮合成酶（ＮＯＳ）活性及环磷酸鸟苷（ｃＧＭＰ）含量明显低于对照组（Ｐ＜００５，Ｐ＜００１）。结论：长期高血糖症可引起血管内皮源性血管舒张因子／一氧化氮（ＥＤＲＦ／ＮＯ）系统出现严重障碍，从而降低了血管舒张功能     

糖尿病大鼠阴茎的氧化应激与阴茎勃起功能障碍的关系

目的 探讨氧化应激在糖尿病性阴茎勃起功能障碍（ED）中的作用。 方法 注射链脲佐菌素建立糖尿病大鼠模型,分别在注射8周和12周后观察阴茎勃起次数;取大鼠阴茎,测定阴茎丙二醛水平、总抗氧化能力,免疫印迹法检测阴茎核因子E2相关因子2(Nrf2)蛋白量的变化。 结果 糖尿病大鼠的阴茎勃起次数明显低于对照组,并随病程延长降低;糖尿病大鼠阴茎丙二醛水平明显高于对照组,总抗氧化能力水平明显低于对照组;与对照组比较,糖尿病组大鼠阴茎内Nrf2蛋白量随病程延长而降低。 结论 糖尿病性阴茎勃起功能障碍与阴茎氧化应激水平升高相关。     

Alternative splicing of human VCAM-1 in activated vascular endothelium.

Vascular cell adhesion molecule 1 (VCAM-1)/inducible cell adhesion molecule 110 is a mononuclear leukocyte-selective adhesion molecule, expressed on vascular endothelium following activation by certain cytokines or endotoxin. This inducible transmembrane protein and member of the immunoglobulin gene superfamily was previously reported to contain six immunoglobulinlike domains. Using the polymerase chain reaction, a VCAM-1 cDNA was obtained from mRNA of interleukin-1 (IL-1)-treated cultured human umbilical vein endothelial cells (HUVEC). The cDNA clone contained an additional 276 base-pair (bp) domain, located between domains 3 and 4. This new domain is most homologous to the existing N-terminal domain (domain 1). The internal 276-bp region is encoded by a single exon of the human VCAM-1 gene, indicating that the two forms of mRNA arise by alternative splicing. Both forms of VCAM-1 mRNA were detected by polymerase chain reaction in IL-1-stimulated HUVEC, although the seven-domain form appeared predominant. On the surface of HUVEC only a 110-kd polypeptide, consistent with the seven-immunoglobulinlike domain form of VCAM-1, was detectable by immunoprecipitation. Alternative splicing of the VCAM-1 gene in cytokine-activated endothelium may generate functionally distinct cell-surface adhesion molecules.     

The role of ENaC in vascular endothelium

Once upon a time, the expression of the epithelial sodium channel (ENaC) was mainly assigned to the kidneys, colon and sweat glands where it was considered to be the main determinant of sodium homeostasis. Recent, though indirect, evidence for the possible existence of ENaC in a non-epithelial tissue was derived from the observation that the vascular endothelium is a target for aldosterone. Inhibitory actions of the intracellular aldosterone receptors by spironolactone and, more directly, by ENaC blockers such as amiloride supported this view. Shortly after, direct data on the expression of ENaC in vascular endothelium could be demonstrated. There, endothelial ENaC (EnNaC) could be defined as a major regulator of cellular mechanics which is a critical parameter in differentiating between vascular function and dysfunction. Foremost, the mechanical stiffness of the endothelial cell cortex, a layer 50–200 nm beneath the plasma membrane, has been shown to play a crucial role as it controls the production of the endothelium-derived vasodilator nitric oxide (NO) which directly affects the tone of the vascular smooth muscle cells. In contrast to soft endothelial cells, stiff endothelial cells release reduced amounts of NO, the hallmark of endothelial dysfunction. Thus, the combination of endothelial stiffness and myogenic tone might increase the peripheral vascular resistance. An elevation of arterial blood pressure is supposed to be the consequence of such functional changes. In this review, EnNaC is discussed as an aldosterone-regulated plasma membrane protein of the vascular endothelium that could significantly contribute to maintaining of an appropriate arterial blood pressure but, if overexpressed, could participate in the pathogenesis of arterial hypertension.     

Suppression of oxidative stress in the endothelium and vascular wall.

There is growing evidence that oxidative stress, meaning an excessive production of reactive oxygen and nitrogen species, underlies many forms of cardiovascular disease. The major source of oxidative stress in the artery wall is an NADPH oxidase. This enzyme complex in vascular cells, including endothelium, differs from that in phagocytic leucocytes in both biochemical structure and functions. The crucial flavin-containing catalytic subunits Nox1 and Nox4 are not present in leucocytes, but are highly expressed in vascular cells and upregulated in vascular remodeling, such as that found in hypertension and atherosclerosis. This offers the opportunity to develop "vascular specific" NADPH oxidase inhibitors that do not compromise the essential physiological signaling and phagocytic function carried out by reactive oxygen and nitrogen molecules. Although many conventional antioxidants fail to significantly affect outcomes in cardiovascular disease, targeted inhibitors of NADPH oxidase that block the source of oxidative stress in the vasculature are more likely to prevent the deterioration of vascular function that leads to stroke and heart attack.     

糖尿病大鼠股骨头血管内皮功能障碍的变化

背景：糖尿病骨病的并发症起病复杂,骨组织血管内皮病变可能是造成的一个重要原因。 目的：探讨糖尿病对大鼠股骨头内皮功能障碍的影响。 方法：将60只大鼠随机等分为对照组和糖尿病组,糖尿病组大鼠腹腔注射链脲佐菌素建立糖尿病模型。 结果与结论：造模15周时,与对照组相比,糖尿病组大鼠股骨头出现骨质疏松显微结构改变,血清一氧化氮水平明显降低,血浆内皮素1水平明显升高,糖尿病组股骨头凝血因子Ⅷ表达明显减少(P < 0.01),提示糖尿病前期就出现内皮功能障碍。微血管增生,糖尿病诱发内皮功能障碍及相互作用与大鼠股骨头功能减退有关。     

卡维地洛对大鼠颈动脉损伤后血管重塑的影响

目的:探讨卡维地洛(carvedilol,CAR)对大鼠颈动脉损伤后血管重塑的影响.方法:雄性Wistar大鼠90只,随机分为假手术组、损伤组和CAR组,后两组行颈动脉球囊损伤术.三组均于术后1、3、7、14、28天处死大鼠.光镜下观察血管损伤后内膜增生情况,用免疫组化和RT-PCR法检测MMP-2、MMP-9和TIMP-1在各组术后不同时间点的表达情况.结果:与损伤组比较,术后14dCAR组内膜面积、内膜与中膜面积比值显著减少,管腔面积显著扩大(P<0.05);与损伤组比较,CAR组术后3-14dMMP-2、MMP-9表达显著减少(P<0.05),而TIMP-1表达无显著变化(P>0.05).结论:卡维地洛有效抑制大鼠颈动脉损伤后MMP-2和MMP-9表达,改善了细胞外基质的合成与降解平衡,抑制血管重塑,减轻再狭窄.