Multimodal on-chip nanoscopy and quantitative phase imaging reveals the nanoscale morphology of liver sinusoidal endothelial cells.

Visualization of three-dimensional (3D) morphological changes in the subcellular structures of a biological specimen is a major challenge in life science. Here, we present an integrated chip-based optical nanoscopy combined with quantitative phase microscopy (QPM) to obtain 3D morphology of liver sinusoidal endothelial cells (LSEC). LSEC have unique morphology with small nanopores (50-300 nm in diameter) in the plasma membrane, called fenestrations. The fenestrations are grouped in discrete clusters, which are around 100 to 200 nm thick. Thus, imaging and quantification of fenestrations and sieve plate thickness require resolution and sensitivity of sub-100 nm along both the lateral and the axial directions, respectively. In chip-based nanoscopy, the optical waveguides are used both for hosting and illuminating the sample. The fluorescence signal is captured by an upright microscope, which is converted into a Linnik-type interferometer to sequentially acquire both superresolved images and phase information of the sample. The multimodal microscope provided an estimate of the fenestration diameter of 119 ± 53 nm and average thickness of the sieve plates of 136.6 ± 42.4 nm, assuming the constant refractive index of cell membrane to be 1.38. Further, LSEC were treated with cytochalasin B to demonstrate the possibility of precise detection in the cell height. The mean phase value of the fenestrated area in normal and treated cells was found to be 161 ± 50 mrad and 109 ± 49 mrad, respectively. The proposed multimodal technique offers nanoscale visualization of both the lateral size and the thickness map, which would be of broader interest in the fields of cell biology and bioimaging.

Brachial Artery Wall Stiffness Assessment by Shear Wave Elastography: A Promising New Diagnostic Tool for Endothelial Dysfunction Detection.

OBJECTIVES: This study was designed to measure the changes in brachial artery wall stiffness by shear wave elastography (SWE) and evaluate the accuracy of SWE changes for detection of endothelial dysfunction. METHODS: Sixty-five consecutive participants (19 patients with atherosclerosis proven by coronary angiography, 16 healthy young adults, 15 patients with cardiovascular risk factors, and 15 healthy older adults between 50 and 60 years) were prospectively included in this study. They were examined in the same week by SWE, and flow-mediated dilatation was evaluated for each patient. RESULTS: The mean flow-mediated dilatation values ± 2 SDs after forearm occlusion were 8.54% ± 1.4% in healthy young adults, 7.61% ± 1.4% in healthy older adults, 5.83% ± 0.7% in patients with risk factors (P < .001), and 3.81% ± 2.4% in patients with atherosclerosis (P < .001, with respect to the risk factor group). There was a significant decrease in stiffness measurements in parallel with the increase in flow-mediated dilatation: 19.9% ± 6.3% in healthy young adults, 16.3% ± 5.1% in healthy older adults, 9.8% ± 5.4% in patients with risk factors (P < .05 with respect to the group with no risk factors), and 7.8% ± 6.4% in patients with atherosclerosis (P < .001 with respect to the healthy older adults). CONCLUSIONS: Shear wave elastography in combination with flow-mediated dilatation could be a promising, widely available noninvasive diagnostic tool for detecting endothelial dysfunction.

Influence of circadian blood pressure profile on endothelial function in patients with and without arterial hypertension.

Little is known about the relationship between the circadian BP rhythm and endothelial function in patients with essential hypertension. Consequently, we have hypothesized, that hypertensive patients with non-dipper circadian BP profile have more deteriorated endothelial function, than those with dipper BP profile. 57 untreated hypertensive patients and 17 normotensive controls were undergone to the anthropometrical measurements, physical examinations, review of their medical histories, 24-hour ABPM and vascular doppler-echography with high resolution ultrasound. Circadian BP profile was not independent from the BP level; namely, dipper profile was more frequent in normotensives. Independent from hypertension, dipper patients had significantly higher FMD%. In the whole study population, FMD showed strong negative correlation with 24-hour SBP, DBP and PP. Our study confirms the presence of disturbed endothelium-dependent vasodilatation in AH. Furthermore, our study showed that non-dipper circadian BP rhythm is associated with the significant impairment of endothelial function. Consequently, we can suggest that patients with non-dipper circadian BP profile could be assessed as a high risk group, which might need permanent supervising for avoiding of future cardiovascular and cerebrovascular complications.

Post-capillary venules are the key locus for transcytosis-mediated brain delivery of therapeutic nanoparticles.

Effective treatments of neurodegenerative diseases require drugs to be actively transported across the blood-brain barrier (BBB). However, nanoparticle drug carriers explored for this purpose show negligible brain uptake, and the lack of basic understanding of nanoparticle-BBB interactions underlies many translational failures. Here, using two-photon microscopy in mice, we characterize the receptor-mediated transcytosis of nanoparticles at all steps of delivery to the brain in vivo. We show that transferrin receptor-targeted liposome nanoparticles are sequestered by the endothelium at capillaries and venules, but not at arterioles. The nanoparticles move unobstructed within endothelium, but transcytosis-mediated brain entry occurs mainly at post-capillary venules, and is negligible in capillaries. The vascular location of nanoparticle brain entry corresponds to the presence of perivascular space, which facilitates nanoparticle movement after transcytosis. Thus, post-capillary venules are the point-of-least resistance at the BBB, and compared to capillaries, provide a more feasible route for nanoparticle drug carriers into the brain.

Assessment of tissue perfusion and vascular function in mice by scanning laser Doppler perfusion imaging.

Post-occlusive reactive hyperemia (PORH) is a key feature of physiological vasomotion to appropriately match the supply/demand ratio of tissues. This adaptive mechanism is severely disturbed in endothelial dysfunction with a reduced flow-mediated dilation (FMD). Reduced PORH and FMD are powerful prognostic risk factors in cardiovascular diseases. While these parameters are frequently determined in human beings, comparable methods applicable to mouse models are sparse. We aimed to evaluate the applicability and accuracy of scanning laser Doppler perfusion imaging (LDPI) to measure PORH in the mouse hindlimb. Changes in mean perfusion in response to vasoactive drugs and PORH (assessed by scanning LDPI) were compared with changes in diameter and blood flow in the femoral artery, as assessed by high-resolution ultrasound. We found that the measured LDPI signal significantly correlated with changes of inflow into the femoral artery. Vasodilation induced by administration of nitroglycerine and acetylcholine increased vessel diameter, blood flow and mean perfusion, while vasoconstriction following administration of epinephrine decreased all three parameters. PORH was induced by temporal occlusion of the femoral artery with an external cuff. During occlusion, mean perfusion decreased to a condition of zero-perfusion and release of the cuff induced an immediate increase in blood flow that was followed by femoral artery dilation driving PORH/perfusion. Surgical removal of the femoral artery decreased mean perfusion to a zero-perfusion level and fully abolished PORH. Importantly, the measurement of the PORH response by scanning LDPI is highly reproducible as determined by repeated measurements and intra/interobserver variation analysis. Last, we found that the PORH response was dependent on nitric oxide synthase and cyclooxygenase and declined with age. Thus, we here provide novel and robust non-invasive methods to serially measure tissue perfusion at baseline and during physiological and pharmacological modulation of vasomotor tone in the hindlimb of mice. The application of these LDPI scanning and ultrasound-based methods may be useful for testing the effects of drugs affecting vasomotor function or future elucidation of mechanisms leading to vasomotor dysfunction in mice in vivo.

In vivo imaging of 64Cu-labeled polymer nanoparticles targeted to the lung endothelium.

UNLABELLED: Nanoparticles (NPs) targeting the intercellular adhesion molecule 1 (ICAM-1) hold promise as a mean of delivering therapeutics to the pulmonary endothelium in patients with acute and chronic respiratory diseases. As these new materials become available, strategies are needed to understand their behavior in vivo. We have evaluated the use of (64)Cu and PET to noninvasively image the lung uptake and distribution of NPs coated with an anti-ICAM antibody. METHODS: Model fluorescent NPs were coated with a mixture of an anti-ICAM antibody (or nonspecific IgG) and (64)Cu-DOTA-IgG (where DOTA is 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid). Biodistribution and small-animal PET and CT studies were performed in healthy mice and in mice pretreated with lipopolysaccharides (LPSs). Metabolism studies were also performed to evaluate the stability of (64)Cu-labeled NPs in lungs in vivo. RESULTS: The lungs of mice administered anti-ICAM NPs labeled with (64)Cu were clearly imaged by small-animal PET 1, 4, and 24 h after administration. Both biodistribution and small-animal imaging showed a 3- to 4-fold higher uptake in the lungs of mice injected with ICAM-targeted NPs relative to that of the control group. Lung uptake was further enhanced by pretreating the mice with LPS, presumably because of ICAM-1 upregulation. However, an approximately 2-fold decrease in lung signal was observed in each experimental group over 24 h. Metabolism studies in lung tissues harvested from mice injected with (64)Cu-labeled anti-ICAM NPs showed considerable release of a small (64)Cu-radiometabolite from the NPs beginning as early as 1 h after injection. A decrease in lung fluorescence was also observed, most likely reflecting partial release of NPs from the lungs in vivo. CONCLUSION: The use of small-animal PET to track (64)Cu-labeled nanostructures in vivo shows potential as a strategy for the preclinical screening of new NP drug delivery agents targeting the lung endothelium and other tissues. Future design optimization to prolong the stability of the radiolabel in vivo will further improve this promising approach.

Coronary and peripheral endothelial function in HIV patients studied with positron emission tomography and flow-mediated dilation: relation to hypercholesterolemia.

BACKGROUND: The mechanisms underlying increased cardiovascular risk in HIV patients in antiretroviral therapy (ART) are not known. Our aim was to study the endothelial function of the coronary arteries by cardiac perfusion positron emission tomography (PET), in HIV patients with normal or high cholesterol levels. Flow mediated dilation (FMD) of the brachial artery and circulating endothelial markers were also assessed. METHODS AND RESULTS: HIV patients in ART with total cholesterol or= 6.5 mmol/L (254 mg/dL; n = 12) and healthy controls (n = 14) were included. (13)NH(3) perfusion PET, FMD, and measurement of plasma levels of E-Selectin, ICAM-1, VCAM-1, tPAI-1, and hs-CRP were performed. Baseline myocardial perfusion and the coronary flow reserve measured by PET (3.2 +/- 0.3, 3.2 +/- 0.3 and 3.0 +/- 0.3; ns) was similar in HIV patients with normal or high total cholesterol and controls. FMD did not differ between the groups and was 4.6 +/- 1.1%, 5.1 +/- 1.2%, and 4.6 +/- 0.8%, respectively. Increased levels of plasma E-Selectin, ICAM-1, tPAI-1, and hs-CRP were found in HIV patients when compared to controls (p < 0.05). E-Selectin and ICAM-1 levels were higher in HIV patients receiving protease inhibitors (PI) compared to those not receiving PI (p < 0.05). None of the measured endothelial biomarkers differed between the normal and high cholesterol HIV groups. CONCLUSIONS: In ART-treated HIV patients with a low overall cardiovascular risk, no sign of endothelial dysfunction was found not even in hypercholesterolemic patients. Also, the increased level of plasma endothelial markers found in HIV patients was not related to hypercholesterolemia.

Papillary endothelial hyperplasia of the adrenal gland: report of a case and review of the literature.

Papillary endothelial hyperplasia (PEH) is a benign vascular proliferative process most frequently seen in the skin and integument, but may involve any of the visceral organs. It is a rare entity, with less than 30 cases of visceral PEH described in the literature. Adrenal papillary endothelial hyperplasia is an exceedingly rare process and is the basis of this review. A 66-year-old female was referred for evaluation of an asymptomatic 6 cm right adrenal mass. Computed tomography indicated that the lesion was solid and hypervascular. After appropriate workup, the patient underwent laparoscopic adrenalectomy. The pathologic analysis was consistent with adrenal PEH. The patient recovered without incident and is doing well at 1 year follow-up. A review of the world's literature on papillary endothelial hyperplasia (PEH), and in particular adrenal PEH, yields five previous reports of this entity, and no comprehensive review. A compilation of the now six patients with adrenal PEH reveals several common features: five of six patients were female and mean age was 64 years. The disease radiologically mimics adrenal cortical carcinoma mandating a surgical oncological technique. Pathologic differentiation from angiosarcoma can be a difficult task requiring evaluation by an experienced pathologist.

Adiposity, but not Obesity, Is Associated With Arterial Stiffness in Young Nulliparous Women.

Subclinical vascular dysfunction is increasingly recognized as an independent risk factor for cardiovascular events and adverse pregnancy outcomes. The evidence linking indices of obesity and vascular dysfunction is mixed. As an example, some data suggest that adiposity may be a better predictor of endothelial dysfunction than body mass index (BMI). The aim of the current study is to compare the association of obesity, as evaluated by BMI, and a direct measure of body fat to biophysical parameters of vascular function including flow-mediated vasodilation and pulse wave velocity (PWV) in healthy nulliparous reproductive-age women. This is a secondary analysis of data collected as a prospective study of prepregnancy physiology in healthy, nulliparous women. Body mass index was calculated as weight (kg)/height (m2). Total and android body fat were calculated by dual-energy X-ray absorptiometry. Brachial PWV and flow-mediated vasodilation were assessed ultrasonographically. Seventy-nine women were evaluated. Mean BMI was 24.4 (5.4) kg/m2, and 15% of women were obese (BMI ≥ 30 kg/m2). In contrast, 39% were considered to have excess adiposity, with ≥39% android body fat. Brachial PWV was associated with increased adiposity, but not obesity. We found no differences in flow-mediated dilation associated with either BMI or body fat. Adiposity may be superior to BMI in identifying women with vascular dysfunction at increased risk of adverse pregnancy outcome and cardiovascular disease. Proper identification may allow implementation of prevention strategies to improve perinatal outcomes and maternal health.

Regional arterial stiffness in central and peripheral arteries is differentially related to endothelial dysfunction assessed by brachial flow-mediated dilation in metabolic syndrome.

The interrelationship between endothelial function and arterial stiffness may be different for central and peripheral arteries due to their structural and functional differences. The study aims to assess the interrelationship between central and peripheral vascular function and haemodynamics in metabolic syndrome. Thirty-seven patients [63.0 (57.5-66.0) years, 68.4% males] of metabolic syndrome (National Cholesterol Education Program - Adult Treatment Panel-III criteria) were studied. Carotid-femoral, carotid-radial pulse wave velocity and augmentation index (AIx@75) were assessed using applanation tonometry. Endothelial function was evaluated by brachial flow-mediated dilation using B-mode ultrasonography. Central and peripheral pressures were measured by radial tonometry and sphygmomanometer, respectively. Carotid-radial pulse wave velocity correlated significantly with peripheral diastolic blood pressure ( r = 0.33, p = 0.04) and inversely with flow-mediated dilation ( r = -0.61, p = 0.0001). AIx@75 correlated significantly with carotid-femoral pulse wave velocity ( r = 0.35, p = 0.03) and with aortic pulse pressure ( r = 0.43, p = 0.01). In principal component analysis, an inverse relationship was observed between flow-mediated dilation and carotid-radial pulse wave velocity but not with carotid-femoral pulse wave velocity. Regional arterial stiffness assessed by pulse wave velocity in central-elastic and peripheral-muscular arteries differentially relates to endothelial dysfunction. The central arteries might be predominantly influenced by endothelial dysfunction-induced structural changes, while the peripheral arteries are majorly affected by functional alterations.

Stereotactic comparison among cerebral blood volume, methionine uptake, and histopathology in brain glioma.

BACKGROUND AND PURPOSE: Vascularity, metabolism, and histologic grade are related in gliomas but the exact determinants of these relationships are not fully defined. We used image coregistration and stereotactic biopsies to regionally compare cerebral blood volume (CBV) and (11)C-methionine (MET) uptake measurements in brain gliomas and to assess their relationship by histopathologic examination. MATERIALS AND METHODS: Fourteen patients with brain gliomas underwent MR imaging, including dynamic susceptibility contrast-enhanced MR and positron-emission tomography (PET) using MET acquired in identical stereotactic conditions before biopsy. MR-based CBV maps were calculated and both CBV maps and PET images were coregistered to anatomic images. Sixty-five biopsy samples were obtained on trajectories targeted toward high MET uptake area. The following histopathologic features were semiquantified in each sample: mitotic activity, endothelial proliferation, cellular pleomorphism, and tumor necrosis. CBV and MET uptake values were measured in the biopsy area and normalized to contralateral white matter. CBV ratios were compared with MET uptake ratios, and both measurements were compared with histologic features of each sample. RESULTS: CBV ratios ranged from 0.08 to 10.24 (median = 1.73), and MET uptake ratios ranged from 0.30 to 4.91 (median = 1.67). There was a positive correlation between CBV ratios and MET uptake ratios (r = 0.65, P < .001). Both CBV and MET uptake ratios were found to be significantly related to endothelial proliferation and mitotic activity (P < .01). CONCLUSION: Within glial tumors, there is a local relationship between CBV and MET uptake measurements. Both provide indices of focal malignant activity.

The breakup of intravascular microbubbles and its impact on the endothelium.

Encapsulated microbubbles (MBs) serve as endovascular agents in a wide range of medical ultrasound applications. The oscillatory response of these agents to ultrasonic excitation is determined by MB size, gas content, viscoelastic shell properties and geometrical constraints. The viscoelastic parameters of the MB capsule vary during an oscillation cycle and change irreversibly upon shell rupture. The latter results in marked stress changes on the endothelium of capillary blood vessels due to altered MB dynamics. Mechanical effects on microvessels are crucial for safety and efficacy in applications such as focused ultrasound-mediated blood-brain barrier (BBB) opening. Since direct in vivo quantification of vascular stresses is currently not achievable, computational modelling has established itself as an alternative. We have developed a novel computational framework combining fluid-structure coupling and interface tracking to model the nonlinear dynamics of an encapsulated MB in constrained environments. This framework is used to investigate the mechanical stresses at the endothelium resulting from MB shell rupture in three microvessel setups of increasing levels of geometric detail. All configurations predict substantial elevation of up to 150 % for peak wall shear stress upon MB breakup, whereas global peak transmural pressure levels remain unaltered. The presence of red blood cells causes confinement of pressure and shear gradients to the proximity of the MB, and the introduction of endothelial texture creates local modulations of shear stress levels. With regard to safety assessments, the mechanical impact of MB breakup is shown to be more important than taking into account individual red blood cells and endothelial texture. The latter two may prove to be relevant to the actual, complex process of BBB opening induced by MB oscillations.

Non-invasive endothelial function assessment using digital reactive hyperaemia correlates with three-dimensional intravascular ultrasound and virtual histology-derived plaque volume and plaque phenotype.

BACKGROUND AND AIM: To study relationships between endothelial dysfunction (ED) and coronary atherosclerosis derived from intravascular ultrasound (IVUS) and virtual histology (VH). METHODS: Endothelial dysfunction was examined by EndoPAT system (Itamar Medical) in 56 patients who underwent IVUS and VH (Volcano corp.). Reactive hyperaemia index (RHI) < 2 was used for definition of ED. IVUS sequences were divided into 5 mm-long non-overlapping and adjacent vessel segments. Plaque phenotype was determined for each frame and 5 mm vessel segment was labeled according to highest frame score (from 0 for "no lesion" to 5 for "thin cap fibroatheroma; TCFA"). RESULTS: IVUS-VH data were collected from 41 patients suitable for three-dimensional analysis. Patients with ED exhibited larger plaque burden than those without ED (0.46 ± 0.08 vs. 0.39 ± 0.07, p = 0.014), smaller lumen area (8.59 ± 2.19 vs. 11.90 ± 3.50, p = 0.016), higher plaque risk score (2.82 ± 1.18 vs. 1.84 ± 0.90, p = 0.012), and higher number of TCFA frames (0.36 ± 0.22 vs. 0.22 ± 0.16, p = 0.038). Relative amounts of fibrous tissue correlated positively with RHI (p = 0.034, r = 0.33). The numbers of fibroatheromas and calcified plaques correlated with RHI inversely (r = -0.34, p = 0.031 and r = -0.32, p = 0.044, respectively). CONCLUSIONS: Endothelial dysfunction correlates with severity and phenotype of coronary lesions and can contribute to non-invasive detection of individuals with higher risk of cardiovascular events.

Peripheral arterial endothelial dysfunction of neurodegenerative diseases.

This study evaluates endothelial functions of neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), progressive supranuclear palsy (PSP), multiple system atrophy (MSA) and spinocerebellar ataxia (SCA). The reactive hyperemia index (RHI) of peripheral arterial tonometry and serological data were compared between age- and gender-matched normal controls (n=302) and five disease groups (ALS; n=75, PD; n=180, PSP; n=30, MSA; n=35, SCA; n=53). Correlation analyses were performed in ALS with functional rating scale-revised (FRS-R), and in PD with the Hehn-Yahr scale (H-Y) and a heart to mediastinum ratio using (123)I-MIBG scintigraphy (MIBG). The RHI of ALS and PD, but not of PSP, MSA or SCA, were significantly lower than normal controls (p<0.01). ALS showed a negative correlation of RHI with serum triglycerides (TG) and immunoreactive insulin (IRI) levels, but not with disease severity (FRS-R) or rates of disease progression (∆FRS-R). On the other hand, PD showed a negative correlation of RHI with a progressive disease severity (H-Y) and a positive correlation of RHI with early/delayed MIBG scintigraphy, but not with serological data. The present study demonstrated significant declines of peripheral arterial endothelial functions in ALS and PD. The RHI of ALS was more correlated with disease duration and serum parameters while the RHI of PD was more correlated with disease severity and MIBG, suggesting different mechanisms of endothelial dysfunction.

The presence of nitrite during UVA irradiation protects from apoptosis.

Nitrite occurs ubiquitously in biological fluids such as blood and sweat, representing an oxidation product of nitric oxide. Nitrite has been associated with a variety of adverse effects such as mutagenicity, carcinogenesis, and toxicity. In contrast, here we demonstrate that the presence of nitrite, but not nitrate, during irradiation of endothelial cells in culture exerts a potent and concentration-dependent protection against UVA-induced apoptotic cell death. Protection is half-maximal at a concentration of 3 mM, and complete rescue is observed at 10 mM. Nitrite-mediated protection is mediated via inhibition of lipid peroxidation in a similar manner as seen with butylated hydroxytoluene, a known inhibitor of lipid peroxidation. Interestingly, nitrite-mediated protection is completely abolished by coincubation with the NO scavenger cPTIO. Using electron paramagnetic resonance (EPR) spectroscopy or Faraday modulation spectroscopy, we directly prove UVA-induced NO formation in solutions containing nitrite. In conclusion, evidence is presented that nitrite represents a protective agent against UVA-induced apoptosis due to photodecomposition of nitrite and subsequent formation of NO.

Non-invasive detection of endothelial dysfunction in sickle cell disease by Doppler ultrasonography.

OBJECTIVE: The purpose of the study was to assess endothelial function in sickle cell disease (SCD), to compare endothelial dysfunction between sickle cell anemia (SS) and sickle cell trait (SA) cases and to evaluate correlation of endothelial dysfunction with duration of symptoms and vaso-occlusive crises per year (voc/year) [severity of disease]. METHODS: We investigated 37 steady state SCD cases, of which 19 were SS [mean age = 23.15 + 5.27 years and M/F = 10/9] and 18 were SA cases [Mean age = 22.05 +/- 5.17 years and M/F = 9/9]. Age, sex, and hemoglobin matched 33 controls [15 (Hb < or = 11g%) for SS cases and 18 (Hb > or = 11g%) for SA cases] were studied. Endothelial function was assessed by flow-mediated dilation (FMD) in brachial artery by vascular Doppler after pneumatic tourniquet stress at forearm (by Celermajer DS, 1992). RESULTS: FMD was significantly impaired in SCD cases [6.22% + 0.91% in SS cases vs. 16.85% + 1.06% in controls, P<0.05 and 12.56% + 0.90% in SA cases vs. 16.99% + 1.05% in controls, P < 0.05]. Endothelial function was impaired more in SS as compared to SA cases (p < 0.05). Decline in endothelial function was observed with increasing duration of symptoms and voc/year in SS cases. CONCLUSION: These results suggest that endothelial function is impaired in SCD and endothelial function is impaired more in SS as compared to SA cases.

Omega-3 fatty acids supplementation improves endothelial function and maximal oxygen uptake in endurance-trained athletes.

The study aimed to evaluate the effects of a 3-week n-3 polyunsaturated fatty acids (n-3 PUFA) supplementation on serum nitric oxide (NO), asymmetric dimethyloarginine (ADMA), ultrasound indices of endothelial function and maximal oxygen uptake (VO2 max) of elite cyclists. The effects of dietary supplementation (n-3 PUFA at a dose of 1.3 g twice daily for 3 weeks) and placebo administration on flow-mediated dilatation (FMD), pulse wave velocity, serum markers (NO, ADMA), lipid profile, and ΔVO2max were analysed in 13 cyclists both before and after dietary protocols. Significant differences between pre- and post-intervention baseline NO levels were observed after n-3 PUFA dietary protocol (13.9 ± 4.2 vs. 23.5 ± 3.6 µmol·l(-1); P < 0.001). Higher post-intervention baseline NO level was observed after n-3 PUFA diet compared with placebo (23.5 ± 3.6 vs. 15.3 ± 3.0 µmol·l(-1); P < 0.01, respectively). The n-3 PUFA increased baseline NO concentration (ΔNO) by 6.7 ± 3.8 µmol·l(-1) and placebo by 1.6 ± 4.4 µmol·l(-1). The positive correlation was observed between baseline post-intervention NO concentration and maximal oxygen uptake (r = 0.72; P < 0.01) and also between ΔNO and ΔVO2max (r = 0.54; P < 0.05) in response to omega-3 fatty acids supplementation. There was an association between a 5.25% higher FMD (P < 0.05) and higherΔVO2max (P < 0.001) after n-3 PUFA diet compared with lower values of placebo (r = 0.68; P < 0.05). These findings suggest that an increase in NO release in response to n-3 PUFA supplementation may play a central role in cardiovascular adaptive mechanisms and enhanced exercise performance in cyclists.

Immunotargeting of streptavidin to the pulmonary endothelium.

UNLABELLED: We have observed previously that monoclonal antibody to angiotensin-converting enzyme (Mab 9B9) accumulates selectively in the lung after intravenous injection. The objective of the present work is the development of a universal system for targeting of drug or radiolabel to the lung, using biotinylated Mab 9B9 and streptavidin. METHODS: Mab 9B9 was biotinylated with biotin succinimide ester (b-Mab 9B9), while streptavidin (SA) was radiolabeled with 125I. Interaction between b-Mab 9B9 and SA has been estimated in solid-phase radioassay. Radiolabeled SA was conjugated with b-Mab 9B9 or with b-IgG and injected intravenously in rats or perfused in isolated rat lungs. RESULTS: Radiolabeled b-Mab 9B9 biotinylated at biotin-to-antibody molar ratio 10 (b-Mab 9B9) retains its ability to accumulate in rat lungs after intravenous injection. Radiolabeled SA conjugated with b-Mab 9B9 accumulates in the lung tissue in perfused isolated rat lungs. About 20% of injected SA accumulates in the rat lung 1 hr after intravenous injection (localization ratio is 20, immunospecificity of the conjugate pulmonary uptake is 70). As compared with conjugate injection, stepwise intravenous injection of b-Mab 9B9 and radiolabeled SA leads to a marked reduction of SA pulmonary uptake. Maximal pulmonary uptake of Mab 9B9 has been observed 2-3 hr after intravenous injection, while 24 hr later, radioactivity in the lung was markedly reduced. In contrast to radiolabeled Mab 9B9 alone, radiolabeled SA conjugated with b-Mab 9B9 was retained in the lung for at least 48 hr. In concert with effective blood clearance of the conjugate, its prolonged lung retention leads to a marked increase in its lung-to-blood ratio: 80 for SA-b-Mab 9B9 versus 15-20 for Mab 9B9. CONCLUSION: Conjugation of Mab 9B9 with streptavidin enhances selective pulmonary uptake of the preparation, providing a background for intrapulmonary immunotargeting of various biotinylated agents.

Pulmonary endothelial permeability following lung transplantation.

During lung transplantation, a number of factors may cause endothelial injury to the donor organ, including ischemia, inadequate preservation, cardiopulmonary bypass, high potassium concentrations, and reperfusion. In this study, protein accumulation index (PAI) was used to assess pulmonary endothelial permeability (PEP) in ten patients immediately after lung transplantation. Six were studied sequentially every other day for ten days postoperatively. The PAI was also measured using the same technique in a group of 11 normal volunteers. Mean PAI x 10(-3)/min +/- (SEM) for ten patients measured within 36 h of transplantation was 1.27 (0.56) compared with 0.45 (0.08) for the normal group (p = 0.09). No correlation was found between preservation time and PAI following reperfusion. Three episodes of lung rejection were observed in two patients during the first ten postoperative days, during which PAI rose to 2.26 (0.26) compared with 0.73 (0.11) for all other studies in the group (p less than 0.01). We conclude that no increase in PEP could be demonstrated after graft reperfusion following lung transplantation as assessed by PAI in this small group of patients. However, further studies may show the technique to be useful in the detection of subsequent episodes of graft rejection.

Impaired endothelial function in hypertensive elderly patients evaluated by high resolution ultrasonography.

BACKGROUND: Multiple investigations both in experimental models and in middle-aged patients with essential hypertension have demonstrated impaired endothelium-dependent vasodilation. OBJECTIVE: To determine whether hypertension exerts an additional negative effect on endothelial function of large arteries in hypertensive elderly patients who may already be affected by endothelial dysfunction due to aging. PATIENTS AND METHODS: Thirteen elderly patients with hypertension (69 9 years of age [mean SD]) were compared with 13 matched healthy elderly subjects (72 6 years of age). High resolution vascular ultrasound was used to measure brachial artery responses to reactive hyperemia (with increased flow causing endothelium-dependent dilation) and to sublingual nitroglycerine (causing endothelium-independent dilation). RESULTS: Flow-mediated diameter (FMD) was significantly impaired in the hypertensive elderly group (6.7 3.3% versus 13.3 3.8% in the control group, P<0.05). No significant difference could be found in nitroglycerine-induced dilation between the elderly control group (12.1 4.9%) and the hypertensive elderly (10.2 6.8%). On simple linear analysis, FMD was inversely correlated with age (r=-0.60, P=0. 03) in the healthy elderly group. FMD in the hypertensive elderly was inversely related to age (r=-0.41, P=0.04) and mean blood pressure (r=-0.67, P=0.01). CONCLUSIONS: This study showed decreased FMD with aging even in the healthy elderly, with a further decline in hypertensive elderly compared with healthy elderly subjects. This impairment of FMD in the hypertensive elderly group was related to age and mean blood pressure, indicating that aging and hypertension may impair endothelial function in the brachial artery of elderly patients with hypertension.