Comparative effects of pitavastatin and probucol on oxidative stress, Cu/Zn superoxide dismutase, PPAR-gamma, and aortic stiffness in hypercholesterolemia

Reactive oxygen species-scavenging enzyme Cu/Zn superoxide dismutase (SOD) regulated by peroxisome proliferator-activated receptors (PPARs) plays an important role in vascular responsiveness. However, it remains unknown whether statin restores vascular dysfunction through the activation of reactive oxygen species-scavenging enzymes in vivo. We hypothesized that pitavastatin restores vascular function by modulating oxidative stress through the activation of Cu/ZnSOD and PPAR-gamma in hypercholesterolemia. New Zealand White male rabbits were fed either normal chow or a 1% cholesterol (CHO) diet for 14 wk. After the first 7 wk, the CHO-fed rabbits were further divided into three groups: those fed with CHO feed only (HC), those additionally given pitavastatin, and those additionally given an antioxidant, probucol. The extent of atherosclerosis was assessed by examining aortic stiffness. When compared with the HC group, both the pitavastatin and probucol groups showed improved aortic stiffness by reducing aortic levels of reactive oxidative stress, nitrotyrosine, and collagen, without affecting serum cholesterol or blood pressure levels. Pitavastatin restored both Cu/ZnSOD activity (P < 0.005) and PPAR-gamma expression and activity (P < 0.01) and inhibited NAD(P)H oxidase activity (P < 0.0001) in the aorta, whereas probucol inhibited NAD(P)H oxidase activity more than did pitavastatin (P < 0.0005) without affecting Cu/ZnSOD activity or PPAR-gamma expression and activity. Importantly, Cu/ZnSOD activity was positively correlated with the PPAR-gamma activity in the aorta (P < 0.005), both of which were negatively correlated with aortic stiffness (P < 0.05). Vascular Cu/ZnSOD and PPAR-gamma may play a crucial role in the antiatherogenic effects of pitavastatin in hypercholesterolemia in vivo.

Viscoelastic measurements after vocal fold scarring in rabbits--short-term results after hyaluronan injection

CONCLUSIONS

The scarring model resulted in significant damage and elevated viscoelasticity of the lamina propria. Hyaluronan preparations may alter viscoelasticity in scarred rabbit vocal folds.

OBJECTIVES

Vocal fold scarring results in stiffness of the lamina propria and severe voice problems. The aims of this study were to examine the degree of scarring achieved in the experiment and to measure the viscoelastic properties after injection of hyaluronan in rabbit vocal folds.

MATERIALS AND METHODS

Twenty-two vocal folds from 15 New Zealand rabbits were scarred, 8 vocal folds were controls. After 8 weeks 12 of the scarred vocal folds received injections with 2 types of cross-linked hyaluronan products and 10 scarred folds were injected with saline. After 11 more weeks the animals were sacrificed. After dissection, 15 vocal folds were frozen for viscoelastic measurements, whereas 14 vocal folds were prepared and stained. Measurements were made of the lamina propria thickness. Viscoelasticity was measured on intact vocal folds with a linear skin rheometer (LSR) adapted to laryngeal measurements.

RESULTS

Measurements on the digitized slides showed a thickened lamina propria in the scarred samples as compared with the normal vocal folds (p<0.05). The viscoelastic analysis showed a tendency to stiffening of the scarred vocal folds as compared with the normal controls (p=0.05). There was large variation in stiffness between the two injected hyaluronan products.

Influence of nebivolol and enalapril on metabolic parameters and arterial stiffness in hypertensive type 2 diabetic patients

OBJECTIVE

To compare the effects of a cardioselective beta-blocker (nebivolol) with those of an angiotensin-converting enzyme inhibitor (enalapril) on parameters of insulin sensitivity, peripheral blood flow and arterial stiffness during one extended glucose clamp experiment.

DESIGN

A randomized, double-blind crossover trial, consisting of two 12-week treatment phases separated by a 4-week wash-out phase.

METHODS

Patients with type 2 diabetes and arterial hypertension were randomly assigned to one of two treatment sequences (nebivolol-enalapril, enalapril-nebivolol). Haemodynamic, metabolic and other laboratory measurements were carried out on the first and last day of each treatment period by means of a glucose clamp experiment that also involved the measurement of blood flow and arterial stiffness.

RESULTS

Twelve patients were included in this study, of which two dropped out early. Efficacy parameters were therefore available for 10 patients. There was no significant difference in any of the primary efficacy parameters. Moreover, the effects on blood pressure did not significantly differ between both treatments. Six adverse events happened during treatment with nebivolol compared with two during treatment with enalapril, but only one was regarded as possibly related to the treatment.

CONCLUSIONS

This pilot study shows that the combined measurement of insulin sensitivity, blood flow and arterial stiffness is feasible. Nebivolol and enalapril did not show different effects with regard to these parameters in hypertensive diabetic patients. If these results are confirmed in larger clinical trials, this would argue against the reservations against beta-blockers as drugs of first choice in patients with diabetes because of potential metabolic side-effects.

A neutrophil elastase inhibitor, sivelestat, improves leukocyte deformability in patients with acute lung injury

BACKGROUND

The objective of this study was to evaluate whether the neutrophil elastase (NE) inhibitor, sivelestat, improves leukocyte deformability and pulmonary function in patients with acute lung injury (ALI).

PATIENTS AND METHODS

Twenty-four patients with systemic inflammatory response syndrome (SIRS) were divided into two groups: those with ALI (ALI group, n = 14), and those without ALI (non-ALI group, n = 10). Within 72 hours after the diagnosis, we measured the total leukocyte count (TLC), C-reactive protein (CRP) level, NE concentration, APACHE II score, Goris multiple organ failure (MOF) index, respiratory index (RI), lung injury score (LIS), and oxygenation index (P/F ratio). Leukocyte deformability was examined with a microchannel array etched on a single-crystal silicon tip that simulates the microvasculature. The number of obstructed microchannels (NOM) because of stiffened neutrophils and transit time (TT), defined as the time needed for 100 microL of whole blood to pass through the microchannels, were determined. We then administered sivelestat (4.8 mg/kg/d) to nine ALI patients (sivelestat group) for 5 days and compared with seven ALI patients treated previously without sivelestat (conventional group). The factors described above were measured before and 5 days after treatment.

RESULTS

There were no significant differences in age, TLC, CRP, APACHE II score, and MOF index between ALI and non-ALI group. RI and LIS were higher and the P/F ratio was significantly lower in the ALI group than in the non-ALI group. NE concentration, NOM, and TT were significantly higher in the ALI group than in the non-ALI group (p < 0.05). After 5 days of treatment with sivelestat, the APACHE II score, MOF index, RI, LIS, NE concentration, TT, and NOM were lower and the P/F ratio was significantly higher than baseline values and those in the conventional group (p < 0.05).

CONCLUSION

NE concentration and neutrophil rigidity are significantly increased in SIRS patients with ALI. Sivelestat appears to reduce NE concentration and neutrophil stiffness and improve pulmonary oxygenation in patients with ALI.

Mouse strain dependence of lung tissue mechanics: Role of specific extracellular matrix composition

This study analyses the differences between C57BL/10 and BALB/c mice in lung tissue micromechanical behaviour and whether specific histological characteristics are related to the mechanical profile. C57BL/10 and BALB/c subpleural lung strips were submitted to multisinusoidal deformation with frequencies ranging between 0.2 and 3.1 Hz. Tissue resistance (R), elastance (E), and hysteresivity (eta) at each frequency were determined before and 30s, 1, 2, and 3 min after acetylcholine (ACh) treatment. BALB/c mice showed higher E and R, at baseline, as well as greater amount of collagen and elastic fibres, and alpha-actin than C57BL/10 mice. However, E, R, and eta augmented with the same magnitude after ACh treatment in both strains. Baseline R was correlated with collagen fibre content and with the volume proportion of alpha-actin, while E was correlated with elastic and collagen fibres, and alpha-actin contents. In conclusion, BALB/c and C57BL/10 mice present distinct tissue mechanical properties that are accompanied by specific extracellular matrix composition and contractile structures.

Ventricular-arterial coupling in a rat model of reduced arterial compliance provoked by hypervitaminosis D and nicotine

The vitamin D(3) and nicotine (VDN) model is one of isolated systolic hypertension (ISH) in which arterial calcification raises arterial stiffness and vascular impedance. The effects of VDN treatment on arterial and cardiac hemodynamics have been investigated; however, a complete analysis of ventricular-arterial interaction is lacking. Wistar rats were treated with VDN (VDN group, n = 9), and a control group (n = 10) was included without the VDN. At week 8, invasive indexes of cardiac function were obtained using a conductance catheter. Simultaneously, aortic pressure and flow were measured to derive vascular impedance and characterize ventricular-vascular interaction. VDN caused significant increases in systolic (138 +/- 6 vs. 116 +/- 13 mmHg, P < 0.01) and pulse (42 +/- 10 vs. 26 +/- 4 mmHg, P < 0.01) pressures with respect to control. Total arterial compliance decreased (0.12 +/- 0.08 vs. 0.21 +/- 0.04 ml/mmHg in control, P < 0.05), and pulse wave velocity increased significantly (8.8 +/- 2.5 vs. 5.1 +/- 2.0 m/s in control, P < 0.05). The arterial elastance and end-systolic elastance rose significantly in the VDN group (P < 0.05). Wave reflection was augmented in the VDN group, as reflected by the increase in the wave reflection coefficient (0.63 +/- 0.06 vs. 0.52 +/- 0.05 in control, P < 0.05) and the amplitude of the reflected pressure wave (13.3 +/- 3.1 vs. 8.4 +/- 1.0 mmHg in control, P < 0.05). We studied ventricular-arterial coupling in a VDN-induced rat model of reduced arterial compliance. The VDN treatment led to development of ISH and provoked alterations in cardiac function, arterial impedance, arterial function, and ventricular-arterial interaction, which in many aspects are similar to effects of an aged and stiffened arterial tree.

Effects of Ascorbic Acid Concentration on the Tissue Engineering of the Temporomandibular Joint Disc

The temporomandibular joint (TMJ) disc is a specialized fibrocartilaginous tissue. When the disc becomes an obstacle and becomes damaged, surgeons have no choice but to perform a discectomy. Tissue engineering may provide a novel treatment modality for TMJ disorder patients who undergo discectomy. No studies have been conducted on the most favourable media for TMJ disc cells. The objective of the current study was to examine the effects on biochemical and biomechanical properties of varying ascorbic acid concentrations (0, 25, or 50 μg/ml) on TMJ disc cells seeded on non-woven PGA scaffolds. The ascorbic acid concentration of the 25 μg/ml group resulted in more effective cell seeding of the scaffolds, with 1.53 million cells per construct, by comparison with the 0 and 50 μg/ml groups which had 1.20 million and 1.32 million cells per scaffold respectively. At week 4, the 25 μg/ml group had a higher collagen content than the 0 μg/ml group, with 30.4 ± 2.7 and 24.9 ± 3.3 μg of collagen per construct respectively. The 25 μg/ml group had a higher aggregate modulus than the 50 μg/ml group, with values of 6.1 ± 1.3 and 4.0 ± 0.9 kPa respectively at week 4. The results of this study indicate that the use of 25 μg/ml of ascorbic acid in culture media is effective for the tissue engineering of the TMJ disc, significantly outperforming media without or with 50 μg/ml of ascorbic acid.

Longterm effects of intraarticular hyaluronan on synovial fluid in osteoarthritis of the knee

OBJECTIVE

Intraarticular (IA) hylan injections constitute second-line therapy for osteoarthritis (OA) of the knee, but human studies suggesting a possible mechanism of action are lacking. We examined the effect of IA Hylan GF-20 injections on synovial fluid (SF) hyaluronan (HA) concentration, viscosity, and elasticity over a 6-month period in patients with mild to moderate OA of the knees.

METHODS

Patients with symptomatic knee OA (Osteoarthritis Research Society International grade 1-2) had SF aspirated from the study knee pre- and 3 and 6 months post-Hylan injection. Primary endpoints included SF HA concentration, viscosity, and elasticity. SF HA concentration was determined using uronic acid assay, and rheology measured using a micro-Fourier rheometer.

RESULTS

Sequential SF samples were available from 32 of 60 subjects injected at baseline (15 men, 17 women; mean age 65 yrs) at 3 months post-injection. The mean HA concentration had increased by 13% (p<0.0008), and the complex shear modulus had increased by 16% (p<0.03). Sufficient SF was also available from 19 of these subjects at 6 months post-injection when mean HA concentration was 2.24+/-0.62 mg/ml compared to their baseline mean of 2.02+/-0.52 mg/ml, an increase of 10% (p<0.053).

CONCLUSION

This open-label study showed a statistically significant change from baseline in both SF HA concentration and complex shear modulus at 3 months following IA Hylan GF-20 injection among subjects with mild to moderate knee OA. These results suggest that one possible mechanism of action of viscosupplementation is to promote endogenous HA production. Longer-term studies are required to identify whether these changes in SF measures are important for modification of disease progression in knee OA.

Knee ligament mechanical properties are not influenced by estrogen or its receptors

Women are at greater risk of tearing their knee anterior cruciate ligament (ACL) than men participating in similar athletic activities. There is currently no conclusive explanation for this disparity; however, as ACL injuries in women have been linked with estrogen fluctuations during the menstrual cycle, one hypothesis is that estrogen has a direct detrimental effect on knee ligament mechanical properties. This study investigated the influence of estrogen and its receptors (ER alpha and ER beta) on knee ligament mechanical properties. This was achieved by testing the viscoelastic and tensile mechanical properties of knee medial collateral ligaments (MCL) and ACLs from: 1) male Sprague-Dawley rats treated with either estrogen (17alpha-ethynylestradiol; 0.03 mg/kg) or an ER alpha-specific agonist (propyl pyrazole triol; 2 mg/kg), and 2) female mice with a null mutation of the gene encoding for ER beta. Estrogen treatment had no significant effects on the viscoelastic or tensile mechanical properties of the rat MCL or ACL. Similarly, pharmacological stimulation of ER alpha using a selective agonist in rats and genetic modulation of ER beta by null mutation of its gene in mice did not influence MCL or ACL properties. These data indicate that estrogen does not have a major direct effect on ligament mechanical properties. Energies for the prevention of the disproportionately high rate of knee ligament injuries in women may be better spent focusing on more established and modifiable risk factors, such as abnormalities in neuromuscular control about the knee.

IL-1beta decreases the elastic modulus of human tenocytes

Cellular responses to mechanical stimuli are regulated by interactions with the extracellular matrix, which, in turn, are strongly influenced by the degree of cell stiffness (Young's modulus). It was hypothesized that a more elastic cell could better withstand the rigors of remodeling and mechanical loading. It was further hypothesized that interleukin-1beta (IL-1beta) would modulate intracellular cytoskeleton polymerization and regulate cell stiffness. The purpose of this study was to investigate the utility of IL-1beta to alter the Young's modulus of human tenocytes. Young's modulus is the ratio of the stress to the strain, E = stress/strain = (F/A)/(deltaL/L0), where L0 is the equilibrium length, deltaL is the length change under the applied stress, F is the force applied, and A is the area over which the force is applied. Human tenocytes were incubated with 100 pM recombinant human IL-1beta for 5 days. The Young's modulus was reduced by 27-63%. Actin filaments were disrupted in >75% of IL-1beta-treated cells, resulting in a stellate shape. In contrast, immunostaining of alpha-tubulin showed increased intensity in IL-1beta-treated tenocytes. Human tenocytes in IL-1beta-treated bioartificial tendons were more tolerant to mechanical loading than were untreated counterparts. These results indicate that IL-1beta reduced the Young's modulus of human tenocytes by disrupting the cytoskeleton and/or downregulating the expression of actin and upregulating the expression of tubulins. The reduction in cell modulus may help cells to survive excessive mechanical loading that may occur in damaged or healing tendons.

Long-term thyrotropin-suppressive therapy with levothyroxine impairs small and large artery elasticity and increases left ventricular mass in patients with thyroid carcinoma

BACKGROUND

Exogenous subclinical hyperthyroidism, caused by long-term thyrotropin (TSH)-suppressive treatment with levothyroxine (LT(4)), is associated with several cardiovascular abnormalities. In order to assess the effect of long-term thyroid hormone-suppressive therapy on the blood vessels and myocardium, we determined the arterial elasticity, using the pulse wave contour analysis.

METHODS AND RESULTS

Twenty-six athyreotic patients receiving TSH-suppressive LT(4) therapy for periods ranging from 3 to 21 years at a mean daily dose of 2.25 +/- 0.5 microg/kg per day were included in the study. Twenty six age- and gender-matched healthy subjects served as controls. Arterial elasticity of large and small arteries was evaluated using pulse wave contour analysis method (HDI CR 200, Eagen, MN). Cardiac structure was assessed by two-dimensional echocardiography. We found decreased large artery elasticity in subclinical hyperthyroidism (sHT) patients compared to controls (14.14 +/- 3.38 versus 10.53 +/- 2.43 L/mm Hg x 100, p < 0.000). Small artery elasticity was also lower in patients than in controls (5.42 +/- 1.82 versus 4.30 +/- 1.75 mL/mm Hg x 100, p < 0.056). The echocardiographic data showed significantly increased left ventricular (LV) mass index (101.90 +/- 18.61 versus 88.03 +/- 22.01 g/m(2), p < 0.049) and interventricular septum thickness (10.61 +/- 1.46 versus 9.11 +/- 1.13 mm, p < 0.002) in LT(4)-treated patients compared to controls.

CONCLUSIONS

We found impaired vascular elasticity of large and small arteries and increased LV mass in patients receiving long-term TSH-suppressive therapy with LT(4).

Recovery of elasticity of aged human epithelial cells in vitro

We recently found a considerable increase in rigidity of human epithelial cells during aging in vitro. This is important because the loss in elasticity of epithelial tissues with aging contributes to many human diseases. We also found that cultured cells had three distinct regions of rigidity and that the increase in rigidity correlated with an increase in density of cytoskeletal fibers. However, it was not clear which type of fiber was important. Atomic force microscopy and immunofluorescence microscopy were used in this study to characterize aging human epithelial cells in vitro, both before and after treatment with cytochalasin B. We found that the fibers associated with increased rigidity were mostly F-actin microfilaments. Furthermore, using cytochalasin B, a chemical that inhibits polymerization of F-actin, we restored the rigidity of old cells to the young level in all three areas of rigidity simultaneously. These results clarify how the cell mechanics changes during aging in vitro, and they may be relevant for treatment of age-related loss of elasticity in epithelial tissues.

Higher small arterial elasticity in hypertensive patients treated with angiotensin II receptor blockers

Although evidence from basic research suggests the involvement of angiotensin II (Ang II) in the progression of arteriosclerosis, the clinical data are limited. In the present study, hypertensive outpatients who were well controlled with antihypertensive medication and had similar blood pressure levels were studied, and arterial elasticity was compared between those receiving Ang II receptor blockers (ARBs) and those treated with other antihypertensive agents. The effects of HMG-CoA reductase inhibitors (STs) on arterial elasticity were also evaluated. The study enrolled 298 outpatients who had been diagnosed with essential hypertension whose blood pressure was controlled to 150/95 or less by antihypertensive treatment (excluding angiotensin converting enzyme [ACE] inhibitors) for at least 2 months. The small artery elasticity index (SAEI) was determined for each patient from the radial artery pulse waves using a non-invasive pulse wave analysis system CR-2000. The mean of two blood pressure measurements taken from subjects lying in a recumbent position during SAEI analysis was used for the data analysis. The patients were grouped according to the use of ARBs and STs, and two-way analysis of variance (ANOVA) was used for statistical comparisons. A backward stepwise multiple regression analysis was carried out to identify factors contributing to the SAEI. Hypertensive patients receiving ARB treatment had a significantly higher SAEI compared to those not receiving ARBs, despite the similar blood pressure levels of both groups. No significant effects of ST treatment on the SAEI were observed (two-way ANOVA). A backward stepwise multiple regression analysis for the SAEI suggested that ARB treatment was an independent determinant of the SAEI after the adjusting of age, gender, total cholesterol, high density lipoprotein cholesterol, smoking and systolic blood pressure. Our results suggested that while providing blood pressure control similar to that of other antihypertensive agents, ARBs may also increase vascular elasticity and thereby delay the progression of arteriosclerosis.

Effect ofD-penicillamine on rat lung elastin cross-linking during the perinatal period

This study was designed to clarify the effects of D-penicillamine (DPA), a drug used for treatment of various pathological events, on lung elastin formation and maturation of the newborn in the perinatal period. The investigation was conducted on 20 newborn rats bred from 40 female and six male rats. DPA doses 400 mg kg(-1) day(-1) and physiological saline were given intraperitoneally (i.p) to experimental and control groups. To assess newborn maturation, their body and lung weights were determined. Serum Cu levels were measured by atomic absorption spectroscopy and ceruloplasmin (Cp) activities were measured spectrophotometrically. Newborn lung tissue elastin, desmosine (DES) and isodesmosine (IDES) levels were measured by HPLC. The results showed that DPA treatment caused loss of skin elasticity and reduction in body and lung weight in newborns of the experimental group. The serum Cu levels and Cp activity were found to be significantly lower in both maternal and newborn of the experimental groups compared with the control group. The lung DES, IDES and elastin values of newborns in the experimental group were decreased compared with the control group. In conclusion, our results indicate that 400 mg kg(-1) day(-1) DPA, a dose that is used in the treatment of Wilson's disease, rheumatoid arthritis and cystinuria, caused the retardation of newborn maturation, a decrease in DES-IDES cross-links and levels of lung elastin of offspring in the perinatal period. Another conclusion to be drawn from this study is that even low levels of Cu depletion due to DPA administration induces a change in cross-linking in lung elastin during the perinatal period.

Nitrite-induced cross-linking alters remodeling and mechanical properties of collagenous engineered tissues

Cumulative damage to long-lived connective tissue proteins play a key role in the development of age-related human diseases such as cardiovascular stiffening and age-related macular degeneration. The processes that result in the accumulation of increasingly insoluble, undigestible damaged collagen are only partially known. Nonenzymatic glycation (NEG) is one such process and has been linked to the development of diabetic-related complications and aging. An additional novel mechanism particularly relevant to smoking- and inflammation-related diseases involves the nonenzymatic nitrite (NEN) modification of connective tissue proteins. The present study was undertaken to examine the effects of NEN of fibrillar type I collagen on cell-mediated remodeling and mechanical properties of collagenous tissues. Using a modification of an in vitro fibroblast-populated collagen gel model system developed in our laboratory, we tested two hypotheses: NEN reduces the ability of primary adult cardiac fibroblasts to remodel type I collagen gels; NEN reduces the deformability of type I collagen gels subjected to mechanical testing. The results show that NEN impairs both cell-mediated remodeling and mechanical deformability in collagenous engineered tissues. Furthermore, these mechanical changes correlate with the degree of cross-linking as determined by SDS-PAGE. Thus, we concluded that NEN reactions may contribute to alterations in the biomechanical properties of collagen-containing tissues consistent with the age-related functional decline observed in human disease.

Long-term effects of hormone therapy on skin rigidity and wrinkles

OBJECTIVE

To evaluate the effects of long-term hormone therapy (HT) on skin rigidity and wrinkling.

DESIGN

Single blinded cross-sectional analysis.

SETTING

Academic medical center.

PATIENT(S)

Sixty-five long-term HT users who underwent menopause at least 5 years before evaluation and who have either consistently used HT or have never used HT.

INTERVENTION(S)

Visual assessment of severity of wrinkles at 11 facial locations using the Lemperle scale by a plastic surgeon blinded to HT use. Measurement of skin rigidity at the cheek and forehead with a durometer.

MAIN OUTCOME MEASURE(S)

Lemperle wrinkle score and skin rigidity.

RESULT(S)

Twenty women met inclusion criteria. Eleven women who had not used HT were compared to nine long-term HT users. Demographics including age, race, sun exposure, sunscreen use, tobacco use, and skin type were similar. Rigidity was significantly decreased in HT users compared to nonusers at both the cheek (1.1 vs. 2.7) and forehead (20 vs. 29). Average wrinkle scores were lower in hormone users than in nonhormone users (1.5 vs. 2.2).

CONCLUSION(S)

Long-term postmenopausal HT users have more elastic skin and less severe wrinkling than women who never used HT, suggesting that hormone therapy may have cosmetic benefits.

Aortic elastic properties in athletes using anabolic-androgenic steroids

The use of anabolic-androgenic steroids (AAS) has been linked to acute cardiovascular events in athletes. The purpose of the present study was to investigate the aortic elastic properties in athletes who had been self-administering AAS compared with a group of athletes not using these drugs. Fourteen male bodybuilders using AAS and 27 male wrestlers (non-users) volunteered to the study. All subjects were placed in a mild recumbent position and the ascending aorta was recorded in the two-dimensional guided M-mode tracings. Although the aortic distensibility was found to be reduced in user athletes (2.1+/-1.1 vs. 3.8+/-1.4 cm(2) dyn(-1) 10(-6), p=0.01; 9.3+/-3.7 vs. 5.9+/-2.5, p=0.003, respectively). The results of this study indicate that aortic stiffness is increasing in athletes using AAS.

Exploring vascular benefits of endothelium-derived nitric oxide

Although the regulation of arterial blood flow has been a subject of intensive medical research, the precise circulatory mechanisms involved are still not fully understood. It has been increasingly recognized that the endothelium plays a vital role in regulating vascular tone, structure, and function. A seminal discovery was made with the identification of endothelium-derived relaxing factor, a key mediator of vasodilation, which was later identified as nitric oxide (NO). Nitric oxide is synthesized from the amino acid L-arginine in the endothelium. Decreased bioavailability of NO is associated with arterial stiffness, hypertension, atherosclerosis, and cardiovascular disease (CVD). Nebivolol is a novel beta-blocker that is highly selective for beta1-adrenergic receptors. Nebivolol also causes vasodilation through a mechanism involving endothelium-derived NO. In clinical studies in hypertensive subjects, nebivolol significantly improves vasodilator responses to endothelium-dependent agonists such as acetylcholine. In addition, nebivolol significantly reduces pulse wave velocity (PWV), a measure of arterial stiffness, whereas the beta-blocker atenolol has no effect on PWV. Because endothelial dysfunction and arterial stiffness play an integral part in the early atherosclerotic process and are associated with poor outcomes and increased mortality, independent of blood pressure, the ability of nebivolol to enhance release of endothelium-derived NO may have significant clinical implications for the use of this agent in the treatment of hypertension and CVD.

Relationships between lung function, smoking and morphology of dermal elastic fibres

OBJECTIVE

To investigate the relationship between lung function and dermal elastic fibres in non-smokers and smokers with and without chronic obstructive pulmonary disease (COPD).

METHOD

A cross-sectional study was performed with lung function as the outcome [forced expiratory volume in the first second (FEV1)%, FEV1/forced vital capacity (FVC)% and residual volume (RV)/total lung capacity (TLC)%] and smoking (pack-years) and morphology of dermal elastic fibres (fibres/mm(2) and percentage histologic field filled with them) as independent variables, with assessment of the associations between these variables by univariate and multivariate testing.

RESULTS

Sixty outpatients reporting chronic cough and/or phle\gm were enrolled (16 non-smokers/44 smokers; COPD: 26, 43.3%). Both lung function and elastic fibres in the reticular dermis (fibres/mm(2)r(s) = 0.36, percentage of the histologic field filled by elastic fibres r(s) = 0.48, P < or = 0.01) correlated with cumulative smoking (Spearman's rank correlation coefficient). Lung function parameters correlated with percentage of the histologic field filled by elastic fibres (FEV1%: r = -0.43; FEV1/FVC%: r = -0.36 and RV/TLC%: r = 0.43; P < or = 0.01, Pearson correlation coefficient), and COPD was significantly related to this morphologic parameter (odds ratio 1.26, 95% confidence interval 1.06-1.48; P = 0.006), associations that depended mainly on cumulative smoking.

CONCLUSION

Lung function impairment with an obstructive pattern is associated with morphologic abnormalities in the reticular dermis appearing in the histologic section as an increase in the percentage of the field filled by elastic fibres. This relationship depends on cumulative smoking and suggests a common effect of smoking on the elastic fibres in both lung and skin.

Elastolytic activity and alveolar epithelial type-1 cell damage after chronic LPS inhalation: effects of dexamethasone and rolipram

This study investigated whether a correlation between leukocyte-derived elastolytic activity, alveolar epithelial type-1 cell damage, and leukocyte infiltration of the airways existed in guinea-pigs chronically exposed to inhaled lipopolysaccharide (LPS). The airway pathology of this model, notably the neutrophilia, resembles chronic obstructive pulmonary disease (COPD). The effect of the corticosteroid, dexamethasone, or the phosphodiesterase-4 (PDE4)-inhibitor, rolipram, on these features was studied. Conscious guinea-pigs were exposed for 1 h to single or repeated (nine) doses of LPS (30 microg ml(-1)). Dexamethasone (20 mg kg(-1), ip) or rolipram (1 mg kg(-1), ip) was administered 24 and 0.5 h before the first exposure and daily thereafter. Bronchoalveolar lavage fluid (BALF) was removed and elastolytic activity determined as the elastase-like release of Congo Red from impregnated elastin. The presence of the specific epithelial cell type-1 protein (40-42 kDa) RT1(40) in BALF was identified by Western blotting using a rat monoclonal antibody and semi-quantified by dot-blot analysis. The antibody was found to identify guinea-pig RT1(40). BALF inflammatory cells, particularly neutrophils and macrophages, and elastolytic activity were increased in chronic LPS-exposed guinea-pigs, the latter by 90%. Chronic LPS exposure also increased (10.5-fold) RT1(40) levels, indicating significant alveolar epithelial type-1 cell damage. Dexamethasone or rolipram treatment reduced the influx of inflammatory cells, the elastolytic activity (by 40% and 38%, respectively), and RT1(40) levels (by 50% and 57%, respectively). In conclusion, chronic LPS-exposed guinea-pigs, like COPD, exhibit elastolytic lung damage. This was prevented by a PDE4 inhibitor and supports their development for suppressing this leukocyte-mediated pathology.

Spironolactone improves carotid artery fibrosis and distensibility in rat post-ischaemic heart failure

Myocardial infarction causes neurohormonal activation involving aldosterone and angiotensin II (AngII). These hormones may increase arterial stiffness, an independent cardiovascular risk factor contributing to progression of congestive heart failure (CHF). This study aimed to determine the effect of aldosterone and AngII blockade on carotid artery distensibility and collagen density in adult Wistar rats with MI-induced CHF. Five groups were studied: Sham-operated, CHF, CHF + spironolactone, CHF + lisinopril, CHF + Spironolactone + Lisinopril. After echocardiography, in vitro isobaric carotid distensibility (echo-tracking technique) and collagen density were measured, and the incremental elastic modulus (Einc) calculated. In the CHF group, intra-ventricular pressure and cardiac weight were increased; carotid distensibility was reduced (CHF: 0.42 +/- 0.30 per mmHg(3) versus sham: 1.75 +/- 0.50 per mmHg(3); P < 0.001), and collagen content increased by 87% when compared to sham. All treatments reduced intra-ventricular pressure, carotid distensibility and fibrosis when compared to CHF but did not change cardiac weight. However, carotid distensibility and intra-ventricular pressure were not completely restored towards sham values and were significantly and inversely related. Spironolactone, which did not decrease significantly blood pressure, was the only drug reducing Einc independently of wall stress (WS). Thus, MI-induced CHF was associated with carotid artery remodeling. This vascular change, which may contribute to maintain cardiac hypertrophy and CHF, is largely prevented by AngII and aldosterone blockade. Only spironolactone reduced the stiffness of carotid wall material independently of blood pressure and WS.

[Effect of vertebral body stiffness before and after vertebroplasty on intradiscal pressure]

Fractures of osteoporotic vertebral bodies are increasingly stabilized with bone cement. The effects of vertebral-body stiffness before and after augmentation with bone cement and of wedge-shaped vertebral body fractures on intradiscal pressure are insufficiently known. In a finite element model of the lumbar spine the elastic modulus of cancellous bone as well as the amount and the elastic modulus of bone cement were varied and the dependency of intradiscal pressure on these parameters was calculated. In addition, a wedge-shaped vertebral-body fracture was simulated. The bulge of the vertebral-body endplate and thus the intradiscal pressure depends strongly on the grade of osteoporosis in the vertebral body. The influence of amount and elastic modulus of bone cement on intradiscal pressure is small. A wedge-shaped vertebral-body fracture causes an anterior shift of upper-body centre of gravity. If this shift is not compensated, it leads to an increased flexion moment that has to be balanced by muscle forces. In addition, this shift leads to a stronger increase of intradiscal pressure than the augmentation of the vertebral body with bone cement.

Nasal wall compliance in vasomotor rhinitis

Nasal compliance is a measure related to the blood volume in the nasal mucosa. The objective of this study was to better understand the vascular response in vasomotor rhinitis by measuring nasal cross-sectional area and nasal compliance before and after mucosal decongestion in 10 patients with vasomotor rhinitis compared with 10 healthy subjects. Nasal compliance was inferred by measuring nasal area by acoustic rhinometry at pressures ranging from atmospheric pressure to a negative pressure of -10 cmH2O. Mucosal decongestion was obtained with one puff per nostril of 0.05% oxymetazoline. At atmospheric pressure, nasal cross-sectional areas were similar in the vasomotor rhinitis group and the healthy subject group. Mucosal decongestion did not induce any decrease of nasal compliance in patients with vasomotor rhinitis in contrast with healthy subjects. Our results support the hypothesis, already proposed, of an autonomic dysfunction based on a paradoxical response of the nasal mucosa in vasomotor rhinitis. Moreover, the clearly different behavior between healthy subjects and vasomotor rhinitis subjects suggests that nasal compliance measurement may therefore represent a potential line of research to develop a diagnostic tool for vasomotor rhinitis, which remains a diagnosis of exclusion.

The relationship between enamel softening and erosion caused by soft drinks at a range of temperatures

OBJECTIVES

Investigations of the erosive potential of soft drinks are usually performed at room or body temperature, but drinks are more frequently served chilled, with ice, or hot. Since the rate of chemical reactions usually increases with temperature, it is predicted that erosion is more severe at high temperatures and reduced at low temperatures. The aim of this study was to investigate the correlation between enamel softening, enamel erosion, and temperature.

METHODS

Atomic force microscopy nanoindentation and non-contact optical profilometry were used to assess changes in enamel nanomechanical properties after 5 min and erosive material loss after 30 min exposure to two different non-carbonated soft drinks at 4, 25, 50 and 75 degrees C.

RESULTS

For one drink (Robinson's Original Juice Drink), there was a statistically significant difference between nanomechanical properties and erosion depth at all temperatures, with softening and erosion increasing with temperature. For another drink (Ribena ToothKind Juice Drink), there was a slight softening and virtually no material loss, and temperature had no statistically significant impact on erosion. There was a good linear correlation (R2 = 0.94) between nanomechanical properties and material loss.

CONCLUSIONS

The difference between the drinks can be explained by their composition. For the erosive drink, material loss increased, and nanohardness decreased, approximately linearly with temperature. The correlation between softening and erosion demonstrated that nanomechanical properties after very short erosion times can be considered a good predictor of bulk material loss after considerably longer erosion times.