bluuebunny/crossref_metadata_2025 huggingface dataset:
Exercise and improved insulin sensitivity in older women: evidence of the enduring benefits of higher intensity training
Authors: DiPietro Loretta , Dziura James , Yeckel Catherine W. , Neufer P. Darrell
Published: September 2005

Few studies have compared the relative benefits of moderate- vs. higher intensity exercise training on improving insulin sensitivity in older people while holding exercise volume constant. Healthy older (73 ± 10 yr) women ( N = 25) who were inactive, but not obese, were randomized into one of three training programs (9-mo duration): 1) high-intensity [80% peak aerobic capacity (V̇o2 peak); TH] aerobic training; 2) moderate-intensity (65% V̇o2 peak; TM) aerobic training; or 3) low-intensity (stretching) placebo control (50% V̇o2 peak; CTB). Importantly, exercise volume (300 kcal/session) was held constant for subjects in both the TH and the TM groups. V̇o2 peak was determined by using a graded exercise challenge on a treadmill. Total body fat and lean mass were determined with dual-energy X-ray absorptiometry. The rate of insulin-stimulated glucose utilization as well as the suppression of lipolysis were determined ∼72 h after the final exercise bout by using a two-step euglycemic-hyperinsulinemic clamp. We observed improved glucose utilization at the higher insulin dose with training, but these improvements were statistically significant only in the TH (21%; P = 0.02) compared with the TM (16%; P = 0.17) and CTB (8%; P = 0.37) groups and were observed without changes in either body composition or V̇o2 peak. Likewise in the TH group, we detected a significant improvement in insulin-stimulated suppression (%) of adipose tissue lipolysis at the low-insulin dose (38–55%, P < 0.05). Our findings suggest that long-term higher intensity exercise training provides more enduring benefits to insulin action compared with moderate- or low-intensity exercise, likely due to greater transient effects.
Monochromatic synchrotron radiation μCT reveals disuse-mediated canal network rarefaction in cortical bone of growing rat tibiae
Authors: Matsumoto Takeshi , Yoshino Masayuki , Asano Takahisa , Uesugi Kentaro , Todoh Masahiro , Tanaka Masao
Published: September 2005

The purpose of this study was to demonstrate the ability of computed microtomography based on monochromatic synchrotron radiation (SRμCT) in microstructural analysis of cortical bone. Tibial diaphyses of growing rats (14 wk, n = 8) undergoing unilateral sciatic neurectomy 8 wk before study were imaged with spatial volume resolution of 5.83 × 5.83 × 5.83 μm3 by SRμCT (20 keV) at the synchrotron radiation facility (SPring-8). Reconstructed image data were translated into local mineral densities by using a calibrated linear relationship between linear absorption coefficients and concentrations of homogeneous K2HPO4 solution. Pure bone three-dimensional images, produced by simple thresholding at a bone mineral density of 0.82 g/cm3, were analyzed for macro- and microscopic structural properties. In neurectomized hindlimbs, cortical canal network rarefaction as well as bone atrophy were found. The former was characterized by 30% smaller porosity, 11% smaller canal density in transverse section, and 38% smaller canal connectivity density than those in contralateral bone. On the other hand, no difference was found in bone mineral density between neurectomized and intact hindlimbs (1.37 vs. 1.36 g/cm3). In conclusion, SRμCT is a promising method for the three-dimensional analysis of cortical microstructure and the degree of mineralization in small animals.
Skeletal muscle myofibrillar mRNA expression in heart failure: relationship to local and circulating hormones
Authors: Toth Michael J. , Ades Philip A. , LeWinter Martin M. , Tracy Russell P. , Tchernof André
Published: September 2005

Chronic heart failure is characterized by changes in skeletal muscle that contribute to exercise intolerance and muscle weakness. To determine whether changes in the quantity and isoform distribution of key myofibrillar proteins are related to altered gene expression, we measured skeletal muscle myofibrillar mRNA abundance in nine heart failure patients (mean ± SE; 63 ± 3 yr) and nine controls (70 ± 3 yr). In addition, we assessed the relationship of circulating levels of anabolic and catabolic hormones, as well as local expression of insulin-like growth factor (IGF)-I, to myofibrillar mRNA abundance. Heart failure patients were characterized by lower abundance of mRNA encoding the myosin heavy chain (MHC) I isoform ( P < 0.01), whereas MHC IIa and MHC IIx mRNA did not differ between groups. Actin mRNA was also lower in heart failure patients compared with controls ( P < 0.001). The expression of each MHC isoform transcript correlated with its respective protein product (MHC I: r = 0.656, P < 0.01; MHC IIa: r = 0.489, P < 0.05; MHC IIx: r = 0.505, P < 0.05; n = 18 for all). In addition to changes in myofibrillar transcripts, we found lower ( P < 0.01) skeletal muscle IGF-1Ea mRNA content in heart failure patients. Myofibrillar mRNA levels were positively associated with skeletal muscle IGF-1Ea transcript levels (range of r values: 0.663–0.765; P values: <0.01 to <0.001) and modestly associated with circulating markers of immune activation (range of r values: −0.487 to −0.555; P values: <0.05 to <0.03). Our findings suggest that alterations in skeletal muscle MHC content and isoform distribution in heart failure may derive, in part, from changes in MHC gene expression. The relationships of myofibrillar mRNA content to both local and circulating hormones further suggest that alterations in the balance between anabolic and catabolic hormones in heart failure patients may influence skeletal muscle myofibrillar protein phenotype by altering gene expression.
Nasal wall compliance in vasomotor rhinitis
Authors: Papon Jean-François , Brugel-Ribere Lydia , Fodil Redouane , Croce Céline , Larger Christian , Rugina Michel , Coste André , Isabey Daniel , Zerah-Lancner Françoise , Louis Bruno
Published: September 2005

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.
Fat adaptation followed by carbohydrate loading compromises high-intensity sprint performance
Authors: Havemann L. , West S. J. , Goedecke J. H. , Macdonald I. A. , St Clair Gibson A. , Noakes T. D. , Lambert E. V.
Published: September 2005

The aim of this study was to investigate the effect of a high-fat diet (HFD) followed by 1 day of carbohydrate (CHO) loading on substrate utilization, heart rate variability (HRV), effort perception [rating or perceived exertion (RPE)], muscle recruitment [electromyograph (EMG)], and performance during a 100-km cycling time trial. In this randomized single-blind crossover study, eight well-trained cyclists completed two trials, ingesting either a high-CHO diet (HCD) (68% CHO energy) or an isoenergetic HFD (68% fat energy) for 6 days, followed by 1 day of CHO loading (8–10 g CHO/kg). Subjects completed a 100-km time trial on day 1 and a 1-h cycle at 70% of peak oxygen consumption on days 3, 5, and 7, during which resting HRV and resting and exercising respiratory exchange ratio (RER) were measured. On day 8, subjects completed a 100-km performance time trial, during which blood samples were drawn and EMG was recorded. Ingestion of the HFD reduced RER at rest ( P < 0.005) and during exercise ( P < 0.01) and increased plasma free fatty acid levels ( P < 0.01), indicating increased fat utilization. There was a tendency for the low-frequency power component of HRV to be greater for HFD-CHO ( P = 0.056), suggestive of increased sympathetic activation. Overall 100-km time-trial performance was not different between diets; however, 1-km sprint power output after HFD-CHO was lower ( P < 0.05) compared with HCD-CHO. Despite a reduced power output with HFD-CHO, RPE, heart rate, and EMG were not different between trials. In conclusion, the HFD-CHO dietary strategy increased fat oxidation, but compromised high intensity sprint performance, possibly by increased sympathetic activation or altered contractile function.
H2-receptor-mediated vasodilation contributes to postexercise hypotension
Authors: McCord Jennifer L. , Beasley Julie M. , Halliwill John R.
Published: September 2005

The early (∼30 min) postexercise hypotension response after a session of aerobic exercise is due in part to H1-receptor-mediated vasodilation. The purpose of this study was to determine the potential contribution of H2-receptor-mediated vasodilation to postexercise hypotension. We studied 10 healthy normotensive men and women (ages 23.7 ± 3.4 yr) before and through 90 min after a 60-min bout of cycling at 60% peak O2 uptake on randomized control and H2-receptor antagonist days (300 mg oral ranitidine). Arterial pressure (automated auscultation), cardiac output (acetylene washin) and femoral blood flow (Doppler ultrasound) were measured. Vascular conductance was calculated as flow/mean arterial pressure. Sixty minutes postexercise on the control day, femoral (Δ62.3 ± 15.6%, where Δ is change; P < 0.01) and systemic (Δ13.8 ± 5.3%; P = 0.01) vascular conductances were increased, whereas mean arterial pressure was reduced (Δ−6.7 ± 1.1 mmHg; P < 0.01). Conversely, 60 min postexercise with ranitidine, femoral (Δ9.4 ± 9.2%; P = 0.34) and systemic (Δ−2.8 ± 4.8%; P = 0.35) vascular conductances were not elevated and mean arterial pressure was not reduced (Δ−2.2 ± 1.3 mmHg; P = 0.12). Furthermore, postexercise femoral and systemic vascular conductances were lower ( P < 0.05) and mean arterial pressure was higher ( P = 0.01) on the ranitidine day compared with control. Ingestion of ranitidine markedly reduces vasodilation after exercise and blunts postexercise hypotension, suggesting H2-receptor-mediated vasodilation contributes to postexercise hypotension.
Buccal capnometry to guide management of massive blood loss
Authors: Cammarata Gianluca A. A. M. , Weil Max Harry , Fries Michael , Tang Wanchun , Sun Shijie , Castillo Carlos J.
Published: September 2005

In both clinical and experimental settings, tissue Pco2 measured in the oral mucosa is a practical and reliable measurement of the severity of hypoperfusion. We hypothesized that a threshold level of buccal tissue Pco2 (Pco2 BU) would prognosticate the effects of volume repletion on survival. Twenty pentobarbital-anesthetized Sprague-Dawley male breeder rats, each weighing ∼0.5 kg, were randomly assigned to one of four groups. Animals were bled over an interval of 30 min in amounts estimated to be 25, 30, 35, or 40% of total blood volume. One-half hour after the completion of bleeding, each animal received an infusion of Ringer lactate solution over the ensuing 30 min in amounts equivalent to two times the volume of blood loss. Pco2 BU was measured continuously with an optical Pco2 sensor applied noninvasively to the mucosa of the left cheek. Arterial pressure and end-tidal CO2 were measured over the same interval. Neurological deficit and 72-h survival were recorded. Aortic pressures were restored to near baseline values for each of the four groups after fluid resuscitation. This contrasted with the improvement of Pco2 BU, which differentiated between animals with short and long durations of postintervention survival. After electrolyte fluid resuscitation in rats subjected to rapid bleeding, noninvasive measurement of Pco2 BU was predictive of outcomes. Neither noninvasive end-tidal Pco2 nor invasive aortic pressure measurements achieved such discrimination. Accordingly, Pco2 BU fulfills the criterion of a noninvasive and reliable measurement to guide fluid management of hemorrhagic shock.
Altered secretion of growth hormone and luteinizing hormone after 84 h of sustained physical exertion superimposed on caloric and sleep restriction
Authors: Nindl Bradley C. , Rarick Kevin R. , Castellani John W. , Tuckow Alexander P. , Patton John F. , Young Andrew J. , Montain Scott J.
Published: September 2005

The pulsatile release of growth hormone (GH) and luteinizing hormone (LH) from the anterior pituitary gland is integral for signaling secretion of insulin-like growth factor (IGF)-I and testosterone, respectively. This study examined the hypothesis that 84 h of sustained physical exertion with caloric and sleep restriction alters the secretion of GH and LH. Ten male soldiers [22 yr (SD 3), 183 cm (SD 7), 87 kg (SD 8)] had blood drawn overnight from 1800 to 0600 every 20 min for GH, LH, and leptin and every 2 h for IGF-I (total and free), IGF binding proteins-1 and -3, testosterone (total and free), glucose, and free fatty acids during a control week and after 84 h of military operational stress. Time-series cluster and deconvolution analyses assessed the secretion parameters of GH and LH. Significant results ( P ≤ 0.05) were as follows: body mass (−3%), fat-free mass (−2.3%), and fat mass (−7.3%) declined after military operational stress. GH and LH secretion burst amplitude (∼50%) and overnight pulsatile secretion (∼50%), IGF binding protein-1 (+67%), and free fatty acids (+33%) increased, whereas leptin (−47%), total (−27%) and free IGF-I (−32%), total (−24%) and free testosterone (−30%), and IGF binding protein-3 (−6%) decreased. GH and LH pulse number were unaffected. Because GH and LH positively regulate IGF-I and testosterone, these data imply that the physiological strain induced a certain degree of peripheral resistance. During periods of energy deficiency, amplitude modulation of GH and LH pulses may precede alterations in pulse numbers.
Corticotropin-Releasing Hormone during Pregnancy Is Associated with Infant Temperament
Authors: Davis Elysia Poggi , Glynn Laura M. , Dunkel Schetter Christine , Hobel Calvin , Chicz-Demet Aleksandra , Sandman Curt A.
Published: September 2005

During pregnancy corticotropin-releasing hormone (CRH) is released into maternal and fetal circulation from the placenta. Elevated concentrations of placental CRH are associated with spontaneous preterm birth, but the consequences for infant development, independent of birth outcome, are unknown. In this study, the effects of placental CRH on infant temperament were examined in a sample of 248 full-term infants. Maternal blood samples were collected at 19, 25 and 31 weeks of gestation for CRH analysis. Infant temperament was assessed with measures of fear and distress at 2 months of age. Infants of mothers with low CRH at 25 weeks of gestation scored lower in fear and distress at 2 months. CRH at 19 and 31 weeks’ gestation was not significantly associated with measures of infant temperament, suggesting the possibility that there is a sensitive period for its effects. These data suggest that prenatal exposure to CRH may exert influences that persist into the postnatal period.
Activated Notch Disrupts the Initial Patterning of Dopaminergic Spinal Cord Neurons
Authors: Binor Elaine , Heathcote R.David
Published: September 2005

Dopaminergic spinal cord neurons differentiate in the ventral spinal cord in a nonrandom dispersed pattern. To test whether Notch signaling was involved in generating the pattern of this neuron population as with others, we overexpressed a constitutively active form of Xenopus Notch (XotchΔE) in developing frog embryos. Overexpression was targeted to half the spinal cord by injecting activated Notch RNA into one blastomere at the two-cell stage. Injected animals showed morphological differences on the injected side including reduced numbers of dopaminergic spinal cord neurons. This is consistent with a role for Notch signaling in establishing the fate of this population in the developing spinal cord. At a later stage of development, dopaminergic neurons continued to differentiate on both sides of the spinal cord, but the difference between experimental and control columns remained constant. This is consistent with transient activation of Notch disrupting the fate of the earliest (primary) but not later (secondary) dopaminergic neurons. The precursors to secondary neurons appear to be refractory to Notch signaling at earlier stages of development.
The Developmentally Regulated Expression of Menkes Protein ATP7A Suggests a Role in Axon Extension and Synaptogenesis
Authors: El Meskini Rajaâ , Cline Laura B. , Eipper Betty A. , Ronnett Gabriele V.
Published: September 2005

Menkes disease (MD) is a neurodegenerative disorder caused by mutation of the copper transporter ATP7A. While several enzymes expressed in mature neurons require copper, MD neurodegenerative changes cannot be explained by known requirements for ATP7A in neuronal development. To investigate additional roles for ATP7A during development, we characterized its pattern of expression using the olfactory system as a neurodevelopmental model. ATP7A expression in neurons was developmentally regulated rather than constitutively. Initially expressed in the cell bodies of developing neurons, ATP7A protein later shifted to extending axons, peaking prior to synaptogenesis. Similarly, after injury-stimulated neurogenesis, ATP7A expression increased in neurons and axons preceding synaptogenesis. Interestingly, copper-transport-deficient ATP7A still exhibits axonal localization. These results support a role for ATP7A in axon extension, which may contribute to the severe neurodegeneration characteristic of MD.
Cognitive Correlates of Cerebral White Matter Lesions and Water Diffusion Tensor Parameters in Community-Dwelling Older People
Authors: Shenkin S.D. , Bastin M.E. , MacGillivray T.J. , Deary I.J. , Starr J.M. , Rivers C.S. , Wardlaw J.M.
Published: September 2005

Background: The biological basis of cognitive ageing is unknown. One underlying process might be disruption of white matter tracts connecting cortical regions. White matter lesions (WML) seen on structural MRI may disrupt cortical connections, but diffusion tensor MRI (DT-MRI) parameters – mean diffusivity () and fractional anisotropy (FA) – may reflect more subtle changes in white matter integrity. Here the relationships between WML load, DT-MRI parameters and cognition in a large cohort of elderly subjects with a very narrow age range were investigated. Methods: 105 community-dwelling volunteers underwent MRI and neuropsychological assessment. Seventy-two (68.6%) were female, and their mean age was 78.4 (SD 1.5) years. Scans were rated for WML load.  and FA were measured from regions of interest in normal-appearing frontal and occipital white matter, and centrum semiovale. Results:  and FA differed significantly among the three brain regions studied (p ≪ 0.01).  increased with age (r = 0.22 to 0.35, p < 0.03), and was negatively correlated with FA (r = –0.20 to –0.51, p < 0.05) in all three regions. There was a trend towards increased WML load correlating with poorer cognitive function, and this was statistically significant for the Mini-Mental State Examination (ρ = –0.23, p = 0.02).  was generally negatively correlated with cognitive test score, and FA was positively correlated. This pattern was more consistent for  than for FA, and particularly for verbal fluency (: r = –0.22 to –0.27, p < 0.03), which measures executive function. Conclusions: DT-MRI parameters, in particular , are sensitive to early ultrastructural changes underlying cognitive ageing. Executive function may be the cognitive domain most sensitive to age-related decline in white matter tract integrity.
ERK and STAT3 Phosphorylation in Sensory Neurons during Capsaicin-Induced Impairment and Nerve Growth Factor Treatment
Authors: Donnerer J. , Liebmann I. , Schicho R.
Published: September 2005

Distinct signal transduction pathways have been shown to regulate injury responses and regeneration in peripheral nerves. In the present investigation, the time courses of the induction of phospho-MAPK/ERK1/2 and of phospho-STAT3 were investigated in the dorsal root ganglia (DRG) and in the sciatic nerve of rats following a systemic capsaicin treatment without or with concomitant intraplantar NGF injections. Western blots were probed with polyclonal antibodies that specifically detect phosphorylated ERK 1/2 and STAT3. Phosphorylation of ERK clearly peaked in the sciatic nerve and in the lumbar DRGs at 6 and 10 h after the capsaicin treatment. In the following 8 days phospho-ERK decreased to very low levels and was found recovered to basal values at the time point 16 days. An additional intraplantar nerve growth factor (NGF) injection at time points 20, 44 and 92 h after the capsaicin treatment, and collection of tissues 4 h later, markedly increased the level of phospho-ERK in the sciatic nerve as well as in the DRG, as compared to the samples taken from rats at the same time points with a capsaicin treatment only. Posphorylated STAT3, which was almost non-detectable in the control sciatic nerve, clearly peaked at 6 h after the capsaicin treatment and decreased again during the following days to almost undetectable levels. The intraplantar NGF injections slightly stimulated phosho-STAT3 in the sciatic nerve. A basal level of phosphorylated STAT3 was present in DRGs of control animals, it remained at a high level up to 6 h after the capsaicin treatment, then markedly decreased and recovered on day 8 and day 16. NGF increased STAT3 phosphorylation in DRG on day 1 and day 2 above the level observed in samples taken from rats at the same time points with a capsaicin treatment only. The present study demonstrates that a capsaicin impairment of small diameter primary sensory neurons followed by an NGF treatment evokes a characteristic pattern of ERK and STAT3 activation indicative of neuronal degeneration and regeneration.
Changes in Plasma Interleukin-18 by Direct Hemoperfusion with Polymyxin B-Immobilized Fiber in Patients with Septic Shock
Authors: Nakamura Tsukasa , Kawagoe Yasuhiro , Suzuki Tsukasa , Shoji Hisataka , Ueda Yoshihiko , Kobayashi Noriyoshi , Koide Hikaru
Published: September 2005

Background/Aims: Polymyxin B-immobilized fiber (PMX-F) treatment is reported to be safe and effective in patients with severe sepsis and septic shock. The aim of the present study was to determine whether plasma levels of interleukin (IL)-18, which is linked with sepsis, are associated with plasma endotoxin levels and sepsis-related scores and whether PMX-F treatment affects these variables in patients with septic shock. Patients and Methods: Twenty-six patients with septic shock (15 men and 11 women; mean age 56.5 years) and 20 age-matched healthy subjects (12 men and 8 women; mean age 54.0 years) were included in this study. Septic shock patients were divided into 2 groups: a PMX-F treatment group (9 men and 5 women; mean age 57.5 years) and a conventional treatment group (7 men and 5 women; mean age 55.3 years). Standard supportive care was continued without change during PMX-F treatment. Plasma endotoxin, plasma IL-18, and clinical variables were measured before, immediately after the first and second PMX-F treatment, and the following day. Results: The plasma IL-18 levels were significantly higher in septic shock patients (1,320 ± 360 pg/ml) than in healthy volunteers (140 ± 60 pg/ml; p < 0.001). The IL-18 level was significantly correlated with the plasma endotoxin level (p < 0.001), the Acute Physiology and Chronic Health Evaluation II score (p < 0.01), the Sepsis Severity Score (p < 0.01), the number of failed organs (p < 0.01), and the Goris score (p < 0.01). PMX-F treatment reduced the plasma endotoxin and IL-18 levels significantly after the first treatment (p < 0.05), after the second treatment (p < 0.01), and on the following day (p < 0.001). However, these variables did not change significantly during conventional treatment. Conclusions: IL-18 may be associated with the severity of septic shock, and PMX-F treatment is effective in reducing the IL-18 level in patients with septic shock.
Novel Mechanism of Vasodilation in Inflammatory Bowel Disease
Authors: Hatoum Ossama A. , Gauthier Kathryn M. , Binion David G. , Miura Hiroto , Telford Gordon , Otterson Mary F. , Campbell William B. , Gutterman David D.
Published: September 2005

Objective—

Endothelium-dependent dilation to acetylcholine (Ach) is reduced in mucosal arterioles from patients with inflammatory bowel disease (IBD). The contributions of both nitric oxide (NO) and endothelial-derived hyperpolarizing factor (EDHF) are decreased. We hypothesized that the remaining dilation results from products of cyclooxygenase.

Methods and Results—

High-performance liquid chromatography (HPLC) was used to isolate eicosanoid vasodilator products and videomicroscopy was used to examine vasomotor responses in human mucosal arterioles from subjects with or without IBD undergoing bowel resection surgeries. In subjects without IBD, Ach constricted (−52%±10%) arterioles devoid of endothelium. Indomethacin (INDO) (cyclooxygenase inhibitor) had no effect. In contrast, Ach dose-dependently dilated both intact and endothelial denuded arterioles from patients with IBD. The dilation was converted to constriction by INDO (−54%±9%;
P
<0.05 versus non-IBD) or by BWA868C (PGD
2
receptor antagonist). Only in arterioles from subjects with IBD did Ach produce an arachidonic acid metabolite that comigrated on HPLC with PG D
2
(PGD
2
). Exogenous PGD
2
dilated (max=66%±4%) IBD arterioles.

Conclusion—

In arterioles from IBD patients, Ach-mediated dilation shifts from endothelial production of NO and EDHF to nonendothelial generation of a PG, likely PGD
2
. This is a novel dilator mechanism arising from nonendothelial vascular tissue that compensates for loss of endothelium-dependent dilation. PGD
2
appears to be important in regulating mucosal blood flow in patients with IBD, implicating potentially detrimental effects from nonsteroidal antiinflammatory drugs.
Trichostatin A Exacerbates Atherosclerosis in Low Density Lipoprotein Receptor–Deficient Mice
Authors: Choi Jae-Hoon , Nam Ki-Hoan , Kim Jiyun , Baek Min Won , Park Jeong-Euy , Park Hyun-Young , Kwon Ho Jeong , Kwon Oh-Seung , Kim Dae-Yong , Oh Goo Taeg
Published: September 2005

Objective—

Histone acetylation has been shown to be involved in expression of a restricted set of cellular genes including various proinflammatory molecules. We aimed to investigate the relationship between histone acetylation and atherosclerosis.

Methods and Results—

In low-density lipoprotein (LDL) receptor-deficient (
Ldlr
−/−
) mice fed an atherogenic diet for 4 or 8 weeks, trichostatin A (TSA), a specific histone deacetylase inhibitor, exacerbated atherosclerosis without alteration on plasma lipid profiles. When we assayed the effects of TSA on expressions of oxidized LDL (oxLDL) receptors on RAW264.7 macrophage, we found that TSA increased CD36 mRNA and protein, as well as cell surface expression of CD36. TSA also increased acetylation at the CD36 promoter region. The uptake of 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine percholate (Dil)-labeled oxLDL was enhanced in RAW264.7 macrophage by TSA. Furthermore, TSA treatment increased CD36 mRNA expression in aorta, and SRA, tumor necrosis factor (TNF)-α, and vascular cell adhesion molecule-1 (VCAM-1) were also elevated, whereas IL-6 and IL-1β expressions were decreased.

Conclusions—

Our findings suggest that histone acetylation could play some role in atherogenesis by modulating expressions of oxLDL receptor and some proatherogenic genes. Therefore, our results indicate that increased histone acetylation may affect the progress of atherosclerosis.
Adrenomedullin
Authors: Kato Johji , Tsuruda Toshihiro , Kita Toshihiro , Kitamura Kazuo , Eto Tanenao
Published: September 2005

Adrenomedullin (AM) is a vasodilator peptide having a wide range of biological actions such as reduction of oxidative stress and inhibition of endothelial cell apoptosis. The AM gene is expressed in vascular walls, and AM was found to be secreted from cultured vascular endothelial cells, smooth muscle cells, and adventitial fibroblasts. Plasma AM levels in patients with arteriosclerotic vascular diseases are elevated in possible association with the severity of the disease. When administered over a relatively short period, AM dilates blood vessels via an endothelium-dependent or independent mechanism. Experiments in vitro have shown that AM exerts multiple actions on cultured vascular cells, which are mostly protective or inhibitory against vascular damage and progression of arteriosclerosis. Either prolonged infusion or overexpression of AM suppressed intimal thickening, fatty streak formation, and perivascular hyperplasia in rodent models for vascular remodeling or atherosclerosis. Intimal thickening induced by periarterial cuff was more severe in AM gene-knockout mice than their littermates, suggesting a protective role for endogenous AM. Moreover, AM has recently been suggested to possess angiogenetic properties. Collectively, a body of evidence suggests that AM participates in the mechanism against progression of vascular damage and remodeling, thereby alleviating the ischemia of tissues and organs.
Impact of Short-Term Administration of High-Density Lipoproteins and Atorvastatin on Atherosclerosis in Rabbits
Authors: Nicholls Stephen J. , Cutri Belinda , Worthley Stephen G. , Kee Patrick , Rye Kerry-Anne , Bao Shisan , Barter Philip J.
Published: September 2005

Objective—This study investigates effects of short-term administration of high-density lipoproteins (HDL) and a statin on atherosclerosis in cholesterol-fed rabbits. Effects of HDL apolipoprotein and phospholipid composition have also been investigated.

Methods and Results—Aortic atherosclerosis was established over 17 weeks in 46 rabbits by balloon denudation and cholesterol feeding. During the past 5 days of the cholesterol-feeding period, animals received: (1) no treatment; (2) oral atorvastatin 5 mg/kg on each of the 5 days; or (3) infusions of HDL (8 mg/kg apolipoprotein A-I) on days 1 and 3 of the treatment phase. After euthanization, lesion size and composition were assessed by histological and immunohistochemical analysis. HDL (but not atorvastatin) reduced lesion size by 36% (P<0.05). The ratio of smooth muscle cells to macrophages in the lesions increased 2.6-fold in animals infused with HDL (P<0.05) and 4-fold in those receiving atorvastatin (P<0.01). HDL and atorvastatin reduced matrix metalloproteinase (MMP)-9 expression by 42% (P<0.05) and 45% (P<0.03), respectively. HDL increased thrombomodulin expression 2-fold (P<0.03). The beneficial effects on lesion area and plaque cellular composition were influenced by HDL phospholipid and apolipoprotein composition.

Conclusion—Infusing small amounts of HDL rapidly reduces lesion size and is comparable to atorvastatin in promoting a stable plaque phenotype.
PAR-1 Activation on Human Late Endothelial Progenitor Cells Enhances Angiogenesis In Vitro With Upregulation of the SDF-1/CXCR4 System
Authors: Smadja David M. , Bièche Ivan , Uzan Georges , Bompais Heidi , Muller Laurent , Boisson-Vidal Catherine , Vidaud Michel , Aiach Martine , Gaussem Pascale
Published: September 2005

Objectives—

The importance of PAR-1 in blood vessel development has been demonstrated in knockout mice. As endothelial progenitor cells (EPCs) are involved in postnatal vasculogenesis, we examined whether they express PAR-1 and whether stimulation by the peptide SFLLRN modulates their angiogenic properties.

Methods and Results—

EPC expanded from human CD34+ cord blood cells expressed PAR-1. PAR-1 activation induced EPC proliferation in a concentration-dependent manner far more potently than that of human umbilical vein endothelial cells. PAR-1 activation also enhanced actin reorganization, promoting both spontaneous migration in a Boyden chamber assay and migration toward SDF-1 and VEGF. As shown by real-time quantitative reverse-transcription polymerase chain reaction (RT-PCR), EPC stimulation by SFLLRN significantly enhanced the mRNA expression of SDF-1 and its receptor CXCR-4. PAR-1 activation also increased CXCR4 expression on EPC and induced SDF-1 secretion, leading to autocrine stimulation. PAR-1 stimulation by SFLLRN also increased the formation of capillary-like structures by EPC in Matrigel, and this effect was abrogated by anti-CXCR-4, anti-SDF-1, and MEK inhibitor pretreatment.

Conclusions—

Human EPCs express functional PAR-1. PAR-1 activation promotes cell proliferation and CXCR4-dependent migration and differentiation, leading to a proangiogenic effect.
CD40 Ligand Influences Platelet Release of Reactive Oxygen Intermediates
Authors: Chakrabarti Subrata , Varghese Sonia , Vitseva Olga , Tanriverdi Kahraman , Freedman Jane E.
Published: September 2005

Objective—

Soluble CD40 ligand (sCD40L) has been recently implicated in the pathogenesis of atherosclerosis. Elevated levels of sCD40L in acute coronary syndrome patients suggests enhanced platelet function; however, the exact mechanism by which this occurs is unknown. In this study, we examined the effect of sCD40L on platelet function and reactive oxygen and nitrogen species (RONS) generation.

Methods and Results—

Platelet stimulation in the presence of recombinant sCD40L (rsCD40L) led to enhanced generation of RONS as measured by DCFHDA oxidation and confocal microscopy. Incubation with rsCD40L led to enhanced platelet P-selectin expression, aggregation, and platelet-leukocyte conjugation. Platelets isolated from CD40L-deficient mice had decreased agonist-induced NO release as compared with wild-type mice. Incubation of platelets with rsCD40L enhanced stimulation-induced p38 MAP kinase and Akt phosphorylation.

Conclusion—

Soluble CD40L enhances platelet activation, aggregation, and platelet-leukocyte conjugation, as well as increases stimulation-induced platelet release of RONS through activation of Akt and p38 MAP kinase signaling pathways. These data suggest that sCD40L regulates platelet-dependent inflammatory and thrombotic responses that contribute to the pathogenesis of atherothrombosis.
A Comparison of Three Different Methods to Evaluate Endothelium-Dependent Vasodilation in the Elderly
Authors: Lind Lars , Fors Nilla , Hall Jan , Marttala Kerstin , Stenborg Anna
Published: September 2005

Background—

Three different techniques to evaluate endothelium-dependent vasodilation in the peripheral circulation have been described but not simultaneously tested in a large-scale population-based setting. This study aimed to evaluate the feasibility and usefulness of these techniques in the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study.

Methods and Results—

In the population-based PIVUS study (1016 subjects aged 70 years), the invasive forearm technique with acetylcholine given in the brachial artery (EDV), the brachial artery ultrasound technique with measurement of flow-mediated dilatation (FMD), and the pulse wave analysis method with β-2-agonist (terbutaline) provocation were successfully used in 87%, 97%, and 86% of the sample, respectively. The results of EDV and pulse wave analysis were interrelated (
r
=0.12,
P
=0.0013), but no relationships were found with FMD measurements. All 3 techniques were correlated to the Framingham risk score (
r
=0.10 to 0.12,
P
=0.0007 to 0.001). In multiple regression analysis, however, only EDV and FMD were independently associated with the Framingham score.

Conclusions—

All 3 evaluated techniques were feasible to perform in a general elderly population. Both the invasive forearm technique and FMD were independently associated with increased coronary risk, suggesting that information on conduit artery and resistance artery endothelial function carry different, but important, information in the elderly. If the invasive technique cannot be used, the pulse wave based technique is an alternative.
Proteinase-Activated Receptor-2 Mediates Arterial Vasodilation in Diabetes
Authors: Roviezzo Fiorentina , Bucci Mariarosaria , Brancaleone Vincenzo , Di Lorenzo Annarita , Geppetti Pierangelo , Farneti Silvana , Parente Luca , Lungarella Giuseppe , Fiorucci Stefano , Cirino Giuseppe
Published: September 2005

Objective—

Proteinase-activated receptor-2 is widely expressed in vascular tissue and in highly vascularized organs in humans and other species. Its activation mainly causes endothelium-dependent vasorelaxation in vitro and hypotension in vivo. Here, using nonobese diabetic (NOD) mice at different disease stages, we have evaluated the role of PAR
2
in the arterial vascular response during diabetes progression.

Methods and Results—

High (NOD-II; 20 to 500 mg/dL) or severe glycosuria (NOD-III; 500 to 1000 mg/dL) provokes a progressive reduction in the response to acetylcholine paralleled by an increase in the vasodilatory response to PAR
2
stimulation. Western blot and quantitative real-time polymerase chain reaction (RT-PCR) studies showed that this effect is tied to an increased expression of PAR
2
coupled to cyclooxygenase-2 expression. Pharmacological dissection performed with specific inhibitors confirmed the functional involvement of cyclooxygenase-2 in PAR
2
vasodilatory effect. This vasodilatory response was confirmed to be dependent on expression of PAR
2
in the smooth muscle component by immunohistochemistry studies performed on aorta isolated by both NOD-III and transgenic PAR
2
mice.

Conclusions—

Our data demonstrate an important role for PAR
2
in modulating vascular arterial response in diabetes and suggest that this receptor could represent an useful therapeutic target.
Single Perivascular Delivery of Mitomycin C Stimulates p21 Expression and Inhibits Neointima Formation in Rat Arteries
Authors: Granada Juan F. , Ensenat Diana , Keswani Amit N. , Kaluza Grzegorz L. , Raizner Albert E. , Liu Xiao-ming , Peyton Kelly J. , Azam Mohammed A. , Wang Hong , Durante William
Published: September 2005

Objective—

Mitomycin C (MMc) is an antibiotic that exerts a potent antiproliferative effect in tumor cells. Because the proliferation of vascular smooth muscle cells (VSMCs) plays a prominent role in the development of restenosis after percutaneous coronary interventions, the present study examined the effect of MMc on VSMC proliferation and on neointima formation after arterial balloon injury.

Methods and Results—

Treatment of cultured rat aortic VSMCs with MMc (1 nmol to 30 μmol/L) inhibited VSMC proliferation in a concentration-dependent manner. Whereas high concentrations of MMc (1 to 30 μmol/L) induced VSMC apoptosis, as reflected by DNA laddering and caspase-3 activation, lower concentrations of MMc (1 to 300 nmol/L) directly inhibited VSMC growth by arresting cells in the G
2
/M phase of the cell cycle. The antiproliferative action of MMc was associated with a selective increase in the expression of the cyclin-dependent kinase inhibitor p21, and with a decrease in cyclin B1-cyclin-dependent kinase-1 complex activity. Finally, the local perivascular delivery of MMc immediately after balloon injury of rat carotid arteries induced p21 expression and markedly attenuated neointima formation.

Conclusion—

These studies demonstrate that MMc exerts a potent inhibitory effect on VSMC proliferation and neointima formation after arterial injury. MMc represents a potentially new therapeutic agent in treating and preventing vasculoproliferative disease.
Consequences and Therapeutic Implications of Macrophage Apoptosis in Atherosclerosis
Authors: Tabas Ira
Published: September 2005

Macrophage apoptosis occurs throughout all stages of atherosclerosis, yet new findings in vivo suggest that the consequences of this event may be very different in early versus late atherosclerotic lesions. In early lesions, where phagocytic clearance of apoptotic cells appears to be efficient, macrophage apoptosis is associated with diminished lesion cellularity and decreased lesion progression. In late lesions, however, a number of factors may contribute to defective phagocytic clearance of apoptotic macrophages, leading to secondary necrosis of these cells and a proinflammatory response. The cumulative effect of these late lesional events is generation of the necrotic core, which, in concert with proatherogenic effects of residual surviving macrophages, promotes further inflammation, plaque instability, and thrombosis. Thus, the ability or lack thereof of lesional phagocytes to safely clear apoptotic macrophages may be an important determinant of acute atherothrombotic clinical events. Further understanding of the mechanisms involved in macrophage apoptosis and phagocytic clearance might lead to novel therapeutic strategies directed against the progression of advanced plaques.
Cardiac Stem Cells Possess Growth Factor-Receptor Systems That After Activation Regenerate the Infarcted Myocardium, Improving Ventricular Function and Long-Term Survival
Authors: Urbanek Konrad , Rota Marcello , Cascapera Stefano , Bearzi Claudia , Nascimbene Angelo , De Angelis Antonella , Hosoda Toru , Chimenti Stefano , Baker Mathue , Limana Federica , Nurzynska Daria , Torella Daniele , Rotatori Francesco , Rastaldo Raffaella , Musso Ezio , Quaini Federico , Leri Annarosa , Kajstura Jan , Anversa Piero
Published: September 2005

Cardiac stem cells and early committed cells (CSCs-ECCs) express c-Met and insulin-like growth factor-1 (IGF-1) receptors and synthesize and secrete the corresponding ligands, hepatocyte growth factor (HGF) and IGF-1. HGF mobilizes CSCs-ECCs and IGF-1 promotes their survival and proliferation. Therefore, HGF and IGF-1 were injected in the hearts of infarcted mice to favor, respectively, the translocation of CSCs-ECCs from the surrounding myocardium to the dead tissue and the viability and growth of these cells within the damaged area. To facilitate migration and homing of CSCs-ECCs to the infarct, a growth factor gradient was introduced between the site of storage of primitive cells in the atria and the region bordering the infarct. The newly-formed myocardium contained arterioles, capillaries, and functionally competent myocytes that with time increased in size, improving ventricular performance at healing and long thereafter. The volume of regenerated myocytes was 2200 μm
3
at 16 days after treatment and reached 5100 μm
3
at 4 months. In this interval, nearly 20% of myocytes reached the adult phenotype, varying in size from 10 000 to 20 000 μm
3
. Moreover, there were 43±13 arterioles and 155±48 capillaries/mm
2
myocardium at 16 days, and 31±6 arterioles and 390±56 capillaries at 4 months. Myocardial regeneration induced increased survival and rescued animals with infarcts that were up to 86% of the ventricle, which are commonly fatal. In conclusion, the heart has an endogenous reserve of CSCs-ECCs that can be activated to reconstitute dead myocardium and recover cardiac function.
Protein Kinase Cδ–Dependent Phosphorylation of Syndecan-4 Regulates Cell Migration
Authors: Chaudhuri Pinaki , Colles Scott M. , Fox Paul L. , Graham Linda M.
Published: September 2005

Endothelial cell (EC) migration is a complex process requiring exquisitely coordinated focal adhesion assembly and disassembly. Protein kinase C (PKC) is known to regulate focal adhesion formation. Because lysophosphatidylcholine (lysoPC), a major lipid constituent of oxidized low-density lipoprotein, can activate PKC and inhibit EC migration, we explored the signaling cascade responsible for this inhibition. LysoPC increased PKCδ activity, measured by in vitro kinase activity assay, and increased PKCδ phosphorylation. Decreasing PKCδ activation, using pharmacological inhibitors or antisense oligonucleotides, diminished the antimigratory effect of lysoPC. LysoPC-induced PKCδ activation was followed by increased phosphorylation of the transmembrane proteoglycan, syndecan-4, and decreased binding of PKCα to syndecan-4, with a concomitant decrease in PKCα activity. A reciprocal relationship was noted between the interaction of PKCα and α-actinin with syndecan-4. These changes were temporally related to the observed changes in cell morphology and the inhibition of migration of ECs incubated with lysoPC. The data suggested that generalized activation of PKCδ by lysoPC initiated a cascade of events, including phosphorylation of syndecan-4, displacement and decreased activity of PKCα, binding of α-actinin to syndecan-4, and disruption of the time- and site-specific regulation of focal adhesion complex assembly and disassembly required for normal cell migration.
Arrestin-Independent Internalization and Recycling of the Urotensin Receptor Contribute to Long-Lasting Urotensin II–Mediated Vasoconstriction
Authors: Giebing Günter , Tölle Markus , Jürgensen Jana , Eichhorst Jenny , Furkert Jens , Beyermann Michael , Neuschäfer-Rube Frank , Rosenthal Walter , Zidek Walter , van der Giet Markus , Oksche Alexander
Published: September 2005

Urotensin II (UII), which acts on the G protein-coupled urotensin (UT) receptor, elicits long-lasting vasoconstriction. The role of UT receptor internalization and intracellular trafficking in vasoconstriction has yet not been analyzed. Therefore, UII-mediated contractile responses of aortic ring preparations in wire myography and rat UT (rUT) receptor internalization and intracellular trafficking in binding and imaging analyses were compared. UII elicited a concentration-dependent vasoconstriction of rat aorta (−log EC50, mol/L:9.0±0.1). A second application of UII after 30 minutes elicited a reduced contraction (36±4% of the initial response), but when applied after 60 minutes elicited a full contraction. In internalization experiments with radioactive labeled VII (125I-UII), ≈70% of rUT receptors expressed on the cell surface of human embryonic kidney 293 cells were sequestered within 30 minutes (half life [th]: 5.6±0.2 minutes), but recycled quantitatively within 60 minutes (th31.9±2.6 minutes). UII-bound rUT receptors were sorted to early and recycling endosomes, as evidenced by colocalization of rUT receptors with the early endosomal antigen and the transferrin receptor. Real-time imaging with a newly developed fluorescent UII (Cy3-UII) revealed that rUT receptors recruited arrestin3 green fluorescent protein to the plasma membrane. Arrestin3 was not required for the endocytosis of the rUT receptor, however, as internalization of Cy3-UII was not altered in mouse embryonic fibroblasts lacking endogenous arrestin2/arrestin3 expression. The data demonstrate that the rUT receptor internalizes arrestin independently and recycles quantitatively. The continuous externalization of rUT receptors provides the basis for repetitive and lasting UII-mediated vasoconstriction.