Nutrition in infancy: implications for practice

The aim of the present study was to assess selective atrophy of the temporal lobe and amygdala in the early stages of Alzheimer dementia (AD). Magnetic resonance imaging (MRI) measurements and the presence of highsignal lesions (HSL) were analysed in 31 patients with mild to moderate probable AD and 22 controls. In the AD group, MRI findings were compared with cognitive variables and specific features of memory functions. Alzheimer patients showed a significant reduction in volumetric measurement compared with controls in the total volume (P < 0.01), temporal lobe (P < 0.01) and amygdala (P < 0.05). The temporal lobe/brain volume ratio was also significantly reduced in AD subjects (P < 0.05). Atrophy of temporal structures was significantly related to the degree of episodic and semantic memory impairment according to a material-specific effect. No significant correlations between amygdala and cognitive variables were found. The results of our study confirm the usefulness of measures of temporal lobe atrophy assessed with MRI in the diagnosis of AD. In contrast, HSL are relatively common in AD patients (12/31 cases) and were not related to volumetric findings, severity of dementia or functional disability.     

Soluble adhesion molecules reflect endothelial cell activation in ischemic stroke and in carotid atherosclerosis

BACKGROUND AND PURPOSE: Activation of endothelial cells and platelets plays an important role in the development of atherosclerosis and thrombotic disorders. Soluble adhesion molecules originating from these cells can be demonstrated in plasma. We hypothesized that elevated plasma concentrations of soluble P-selectin (sP-selectin), soluble intercellular adhesion mole-cule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), and soluble E-selectin (sE-selectin) can reflect activation of endothelial cells and/or platelets in acute ischemic stroke and in previously symptomatic internal carotid artery stenosis. METHODS: Plasma was sampled from patients within 2 days of acute ischemic stroke (n = 28), from patients with a previous (> 1 week) transient or persistent ischemic neurological deficit associated with stenosis of the internal carotid artery (n = 34), and from control patients without a history of vascular disease (n = 34). Concentrations of sP-selectin, sICAM-1, sVCAM-1, and sE-selectin were measured by means of an enzyme-linked immunosorbent assay. RESULTS: Compared with control subjects, sP-selectin and sE-selectin were significantly elevated in the acute stage of ischemic stroke (P < .0001 and P = .001, respectively) as well as in previously symptomatic carotid stenosis (P < .0001 and P = .0007). sICAM-1 and sVCAM-1 were not increased. CONCLUSIONS: The elevated levels of sE-selectin indicate that endothelial cell activation occurs both in the acute stage of ischemic stroke and in previously symptomatic carotid atherosclerosis. Increased sP-selectin concentrations reflect endothelial cell activation as well but may also be caused by platelet activation.     

Alteration of endothelial cell monolayer integrity triggers resynthesis of vascular endothelium cadherin

Although cadherins appear to be necessary for proper cell-cell contacts, the physiological role of VE-cadherin (vascular endothelium cadherin) in adult tissue has not been clearly determined. To shed some light on this question, we have disturbed the adhesive function of VE-cadherin in human endothelial cell culture using a polyclonal anti-VE-cadherin antibody. This antibody disrupts confluent endothelial cell monolayers in vitro and transiently generates numerous gaps at cell-cell junctions. The formation of these gaps correlates with a reversible increase in the monolayer permeability. We present evidence that destruction of the homotypic interactions between the extracellular domains of VE-cadherin induces a rapid resynthesis of VE-cadherin, leading to restoration of endothelial cell-cell contacts. The expression of new molecules of VE-cadherin correlates with a modest but significant increase in VE-cadherin mRNA synthesis. Altogether, these results establish a critical role for VE-cadherin in the maintenance and restoration of endothelium integrity.     

Aspirin improves endothelial dysfunction in atherosclerosis

Archival paraffin-embedded tissue from 5 normal adrenal glands (including 1 from a fetus of 28 weeks' gestation), 6 cases of adrenal cortical hyperplasia, 9 cortical adenomas, 14 cortical carcinomas, and 11 pheochromocytomas were immunostained with monoclonal antibody against bcl-2. Ultrastructural localization of bcl-2 protein was also performed on selected cases. Positive immunostaining for bcl-2 was seen in all of the layers of the normal adrenal cortex, with different staining characteristics. bcl-2 expression was never observed in the normal adrenal medulla. Electron microscopic studies revealed bcl-2 to be localized predominantly to mitochondria, with a small number of labels along the nuclear envelope. Analysis of adrenal neoplasms showed expression of bcl-2 in cortical tumors, but only one positive case in pheochromocytomas. Restriction of bcl-2 expression to adrenal cortex-derived tissue versus adrenal medulla-derived tissue might prove to be helpful for the differential diagnosis between cortical and medullary tumors.     

Minimally invasive saphenous vein harvesting: endothelial integrity and early clinical results

Eddy current effects induced by switched gradients in proximal conducting structures are traditionally reduced by applying preemphasis currents whose amplitudes and decay characteristics must be set to offset the eddy current fields. We present an expeditious, localized, and quantitative method for mapping and adjusting the parameters for eddy current compensation. Mapping is based on analysis of projections as used in the fast automatic shimming technique by mapping along projections (FASTMAP). Adjustment methods are demonstrated in high-field horizontal bore systems. The proposed localized eddy current mapping technique may also be used for localized measurements in situations where asymmetric conducting structures may cause nonlinear eddy current fields, such as in interventional MRI and open magnet designs.     

Adhesion of leukocytes to endothelial cells in atherosclerosis]

The adherence of blood monocytes to the endothelium, followed by transmigration beneath the endothelium, are initiating events in the formation of foam cells, promoting atherogenesis. We showed that adhesion molecules on leukocytes were up- or down-regulated in atherosclerosis, when binding of monoclonal antibodies was measured by indirect immunofluorescence with flow cytometry. Expression of PE-CAM-1 (CD31) on monocytes and LFA-1 (CD11a) on lymphocytes was increased with age. Expression of PECAM-1 in monocytes was also up-regulated in patients with coronary artery disease. Being unchanged on aging, expression of HAR (CD44) on polymorphonuclear leukocytes and monocytes was increased in patients with coronary artery disease. On the other hand, expression of L-selectin (CD62L) on polymorphonuclear leukocytes, and LFA-1, CR3 (CD11b) and VLA-4 (CD49d) on monocytes was decreased. These findings may show the mechanism of increased chemotaxis of monocytes beneath the endothelium during the incipient stage of atherosclerosis.     

Reduced endothelial nitric oxide synthase expression and production in human atherosclerosis

BACKGROUND: NO regulates vascular tone and structure, platelets, and monocytes. NO is synthesized by endothelial NO synthase (eNOS). Endothelial dysfunction occurs in atherosclerosis. METHODS AND RESULTS: With a porphyrinic microsensor, NO release was measured in atherosclerotic human carotid arteries and normal mammary arteries obtained during surgery. eNOS protein expression was analyzed by immunohistochemistry. In normal arteries, the initial rate of NO release after stimulation with calcium ionophore A23187 (10 micromol/L) was 0.42+/-0.05 (micromol/L)/s (n=10). In contrast, the initial rate of NO release was markedly reduced in atherosclerotic segments, to 0.08+/-0.04 (micromol/L)/s (n=10, P<0.0001). NO peak concentration in normal arteries was 0.9+/-0.09 micromol/L (n=10) and in atherosclerotic segments, 0.1+/-0.03 micromol/L (n=10, P<0.0001). Reduced NO release in atherosclerotic segments was accompanied by marked reduction of immunoreactive eNOS in luminal endothelial cells, although specific endothelial cell markers (CD31) were present (n=13). Endothelial cells of vasa vasorum of atherosclerotic segments, however, remained positive for eNOS, as was the endothelium of normal arteries. CONCLUSIONS: In clinically relevant human atherosclerosis, eNOS protein expression and NO release are markedly reduced. This may be involved in the progression of atherosclerosis.     

Evidence against an effect of endothelin-1 on blood coagulation, fibrinolysis, and endothelial cell integrity in healthy men

On the basis of an array of preclinical experimental results, it has been widely assumed that endothelin-1 (ET-1) may affect blood coagulation, fibrinolysis, and endothelial cell function, thereby playing a pathophysiological role in various cardiovascular diseases in humans. However, confirmation of this assumption is still lacking. ET-1 or placebo was administered intravenously to 12 healthy volunteers in a prospective, randomized, double-blind, crossover trial. Pathophysiologically relevant concentrations of ET-1 (an approximate threefold increase of normal blood levels) causing hemodynamic effects were reached by continuous intravenous infusion for 6 hours. Components of the coagulation (thrombin-antithrombin complexes, prothrombin fragment F1 + 2, activated factor VII, and factor VII antigen) and fibrinolytic (fibrin split product D-dimer, plasmin-plasmin inhibitor complex, tissue-type plasminogen activator, urokinase-type plasminogen activator, and plasminogen activator inhibitor-1) systems and markers of endothelial cell perturbation/dysfunction (von Willebrand factor and thrombomodulin) were measured before the start of infusion and after 2, 6, 12, and 24 hours. Comparing changes in the plasma concentrations of these parameters during and after infusion of ET-1 and placebo, we found no specific effects of ET-1. In contrast to previous reports from preclinical experiments, ET-1 does not appear to affect coagulation or fibrinolysis, nor does this peptide induce relevant endothelial cell perturbations in humans.     

Clinical implications of endothelial dysfunction

Endothelial dysfunction is increasingly recognized as an early event in the pathogenesis of cardiovascular disease. This observation is consistent with the growing appreciation of the role of endothelium in maintaining cardiovascular health. Endothelial dysfunction and coronary artery disease are both linked to hypertension, hypercholesterolemia, diabetes mellitus, and cigarette smoking. Modification of these conditions improves both endothelial function and coronary artery disease outcomes. Dietary and lifestyle modifications and antioxidant vitamin supplementation have a beneficial effect on endothelial function, as do angiotensin-converting enzyme inhibitors and lipid-lowering agents. Future studies will determine whether interventions that specifically target endothelial dysfunction can reduce rates of clinical disease.     

Epithelial integrity, cell death and cell loss in mammalian small intestine

In recent years, the different mechanisms of epithelial cell loss which occur in mammalian and avian small intestine have been re-investigated. Information is now available for a variety of mammalian types and mechanisms can be divided into two major classes: [i] those preserving epithelial integrity by maintaining intercellular tight junctions throughout early-to-late stages of cell extrusion; and [ii] those which compromise integrity by introducing breaches in epithelial continuity. Both classes are associated with the activity and/or proximity of non-epithelial cells (mainly lymphocytes and mononuclear phagocytes) located in the epithelium or underlying lamina propria. Intraepithelial lymphocytes may be involved in enterocyte targetting and killing whilst lamina propria (LP) macrophages sequester cell debris. Where epithelial integrity is maintained, two types of loss can be identified. In the first (type 1), complete cells are extruded into the lumen. In the second (type 2), only anucleate apical cell fragments pass into the lumen. There are two variants of type 2 loss distinguishable by the fate of the nucleated basal portions of cells. One variant (type 2a) creates large intercellular spaces extending from the preserved apical cap to the basal lamina and containing enterocyte debris for phagocytosis. The second (type 2b) involves the gradual shrinkage of individual cells (which become more electron-dense) and in situ degeneration of their nucleated subapical portions in increasingly narrower intercellular spaces between adjacent healthy enterocytes. The mechanism of removal of these fragments is unclear but may be via macrophages or surrounding enterocytes. Apoptosis has been implicated in both type 1 and type 2 extrusion. In contrast, type 3 loss involves morphological changes in enterocytes which are reminiscent of those seen in necrosis and is accompanied by breaks in epithelial continuity following cell swelling, a decrease in cell electron density and total or subtotal degradation of organelles and membranes. It ends in loss of either an abnormal cell apex (with subsequent exposure of the degraded cell contents and their spillage into the lumen) or a complete cell remnant (extruded into the lumen before total disintegration of plasma membranes).     

Apoptosis in restenosis versus stable-angina atherosclerosis: implications for the pathogenesis of restenosis

Decreases in programmed cell death (apoptosis) may contribute to restenotic hyperplasia by prolonging the life span of intimal cells. Apoptotic events were compared in restenotic versus primary lesions, by using atherectomy samples from 16 restenotic and 30 primary human peripheral and coronary lesions from patients presenting with stable angina. We used transmission electron microscopy to identify apoptosis, quantify its frequency, distinguish apoptosis from necrosis, and relate these events to cellular composition. Smooth muscle cell (SMC) density was higher in restenotic versus primary lesions (P<0.0001), whereas the number of macrophages was significantly reduced (P<0.01) and the number of lymphocytes was lower, but not significantly (P=0.06). As the main finding, restenotic lesions contained fewer apoptotic cells compared with primary lesions (3% versus 13%, P=0.002), whereas no differences were found for cellular necrosis. With regard to cell type, the lower frequency of apoptotic cells observed in restenotic tissue was attributable to both SMCs and macrophages. The key finding of less apoptosis in restenotic versus primary lesions was in agreement with terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) analysis (2% versus 9%, P<0.001). For all lesions analyzed, significant inverse correlations were observed between the density of SMCs and the frequency of apoptotic cell death (r=-0.60, P<0.001) as well as the density of SMCs and that of macrophages (r=-0.74, P<0.001). No relationship was seen between the frequency of apoptosis and the density of macrophages. In conclusion, the data of the present study indicate that a low level of apoptosis may be an important mechanism leading to restenotic intimal lesion development after interventional procedures.     

Hypertension, aging, and atherosclerosis. The endothelial interface

Hypertension, atherosclerosis, and aging are considered major independent risk factors for cardiovascular morbidity and mortality. Although independent as risk factors, the three entities are closely related and often operate simultaneously to affect the cardiovascular system adversely, resulting in damage to various organs. This article evaluates the evidence that endothelial damage may be the underlying pathophysiologic mechanism that connects the three entities.     

Association of atherosclerosis and cardiac cell dysfunction

It is recognized that heart failure in patients with atherosclerotic lesion is the result of ischemia. However, there may also be cardiac cell dysfunction independent of ischemia, as factors advancing both of atherosclerosis and heart failure are discovered. The renin-angiotensin system is one of factor and angiotensin-converting enzyme inhibitor (ACEi) prevents progression of atherosclerotic lesion and heart failure. To elucidate the association of atherosclerosis and cardiac cell dysfunction, we investigated the effects of ACEi on cultured cardiac myocytes. Captopril increased beta-receptor density of myocytes and augmented the response to isoproterenol. CV-3480, a ACEi, also up-regulated beta-receptors but angiotensin I, angiotensin II and angiotensin type I receptor antagonist did not. Bradykinin B2 receptor blocker, HOE140, suppressed the effect of captopril on cultured cells. The results suggest that ACEi up-regulated beta-receptors and augmented the response to beta-receptor agonist through BK potentiation.     

Platelet endothelial cell adhesion molecule-1 expression modulates endothelial cell migration in vitro

Arabidopsis thaliana seeds imbibed for a short duration show phytochrome B (PhyB)-specific photo-induction of germination. Using this system, the relationship was determined between the amount of PhyB in seeds and photon energy required for PhyB-specific germination in two transgenic Arabidopsis lines transformed with either the Arabidopsis PhyB cDNA (ABO) or the rice PhyB cDNA (RBO). Immunochemical detection of PhyB apoprotein (PHYB) showed that the expression level of PHYB in ABO seeds was at least two times higher than that in the wild-type seeds, but in RBO seeds the PHYB level was indistinguishable from that in wild-type seeds. The photon fluence required for induction and photoreversible inhibition of germination was examined using the Okazaki large spectrograph. At the wavelengths of 400-710 nm, the ABO seeds required significantly less photon fluence than wild-type seeds for induction of germination, whereas the RBO seeds required similar fluence to wild-type seeds. A critical threshold wavelength for either induction or inhibition of germination of ABO seeds shifted towards the longer wavelengths relative to wild-type seeds. By assuming that PhyA and PhyB are similar in their photochemical parameters, amounts of Pfr at each wavelength were calculated. The photon fluence required for 50% germination was equivalent to the fluence generating a Pfr/Ptot ratio of 0.21-0.43 in wild-type seeds, and of 0.035-0.056 in ABO seeds. These results indicate that PhyB-specific seed germination is not strictly a function of the Pfr/Ptot ratio, but is probably a function of the absolute Pfr concentration.     

T lymphocytes induce endothelial cell matrix metalloproteinase expression by a CD40L-dependent mechanism: implications for tubule formation

Neovascularization frequently accompanies chronic immune responses characterized by T cell infiltration and activation. Angiogenesis requires endothelial cells (ECs) to penetrate extracellular matrix, a process that involves matrix metalloproteinases (MMPs). We report here that activated human T cells mediate contact-dependent expression of MMPs in ECs through CD40/CD40 ligand signaling. Ligation of CD40 on ECs induced de novo expression of gelatinase B (MMP-9), increased interstitial collagenase (MMP-1) and stromelysin (MMP-3), and activated gelatinase A (MMP-2). Recombinant human CD40L induced expression of MMPs by human vascular ECs to a greater extent than did maximally effective concentrations of interleukin-1beta or tumor necrosis factor-alpha. Moreover, activation of human vascular ECs through CD40 induced tube formation in a three-dimensional fibrin matrix gel assay, an effect antagonized by a MMP inhibitor. These results demonstrated that activation of ECs by interaction with T cells induced synthesis and release of MMPs and promoted an angiogenic function of ECs via CD40L-CD40 signaling. As vascular cells at the sites of chronic inflammation, such as atherosclerotic plaques, express CD40 and its ligand, our findings suggest that ligation of CD40 on ECs can mediate aspects of vascular remodeling and neovessel formation during atherogenesis and other chronic immune reactions.     

Vesicular transport: implications for cell polarity

In polarized cells intracellular sorting of plasma membrane proteins occurs to a large extent at the trans-Golgi network, giving rise to vesicles destined for distinct plasma membrane domains. This review discusses the several pathways, both direct and indirect, which lead to protein incorporation into the correct cell surface, as well as the mechanisms involved. Proteins contain signals which direct their incorporation into the distinct vesicles destined for plasma membrane microdomains. Specific coat proteins are involved in vesicle assembly and are likely to play a role in the generation of discrete vesicle populations. Molecules involved in vesicle docking and fusion may also add specificity to the targeting process.