bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of retinoic acid on cell proliferation and differentiation as well as on lipid synthesis, lipoprotein secretion, and apolipoprotein biogenesis
Authors: Grenier Emilie , Maupas Françoise Schwalm , Beaulieu Jean-François , Seidman Ernest , Delvin Edgard , Sane Alain , Tremblay Eric , Garofalo Carole , Levy Emile
Published: October 2007

Dietary vitamin A and its active metabolites are essential nutrients for many functions as well as potent regulators of gene transcription and growth. Although the epithelium of the small intestine is characterized by rapid and constant renewal and enterocytes play a central role in the absorption and metabolism of alimentary retinol, very little is known about the function of retinoids in the human gastrointestinal epithelium and mechanisms by which programs engage the cell cycle are poorly understood. We have assessed the effects of 10 μM 9- and 13- cis-retinoic acid (RA) on proliferation and differentiation processes, lipid esterification, apolipoprotein (apo) biogenesis and lipoprotein secretion along with nuclear factor gene transcription. Treatment of Caco-2 cells with RA at different concentrations and incubation periods revealed the reduction of thymidine incorporation in 60% preconfluent or 100% confluent cells. Concomitantly, RA 1) modulated D-type cyclins by reducing the mitogen-sensitive cyclin D1 and upregulating cyclin D3 expressions and 2) caused a trend of increase in p38 MAPK, which triggers CDX2, a central protein in cell differentiation. RA remained without effect on lipoprotein output and apo synthesis, even for apo A-I that possesses RARE in its promoter. RA, in combination with 22-hydroxycholesterol, could induce apo A-I gene expression without any impact on apo A-I mass. Only the gene expression of peroxisome proliferator-activated receptor (PPAR)β, retinoic receptor (RAR)β, and RARγ was augmented and no alteration was noted in PPARα, PPARγ, liver X receptor (LXR)α, LXRβ, and retinoid X receptors. Taken together, these data highlight RA-induced cell differentiation via specific signaling without a significant impact on apo A-I synthesis.
Duodenal brush border intestinal alkaline phosphatase activity affects bicarbonate secretion in rats
Authors: Akiba Yasutada , Mizumori Misa , Guth Paul H. , Engel Eli , Kaunitz Jonathan D.
Published: October 2007

We hypothesized that duodenal HCO3−secretion alkalinizes the microclimate surrounding intestinal alkaline phosphatase (IAP), increasing its activity. We measured AP activity in rat duodenum in situ in frozen sections with the fluorogenic substrate ELF-97 phosphate and measured duodenal HCO3−secretion with a pH-stat in perfused duodenal loops. We examined the effects of the IAP inhibitors l-cysteine or l-phenylalanine (0.1–10 mM) or the tissue nonspecific AP inhibitor levamisole (0.1–10 mM) on AP activity in vitro and on acid-induced duodenal HCO3−secretion in vivo. AP activity was the highest in the duodenal brush border, decreasing longitudinally to the large intestine with no activity in stomach. Villous surface AP activity measured in vivo was enhanced by PGE2intravenously and inhibited by luminal l-cysteine. Furthermore, incubation with a pH 2.2 solution reduced AP activity in vivo, whereas pretreatment with the cystic fibrosis transmembrane regulator (CFTR) inhibitor CFTRinh-172 abolished AP activity at pH 2.2. l-Cysteine and l-phenylalanine enhanced acid-augmented duodenal HCO3−secretion. The nonselective P2 receptor antagonist suramin (1 mM) reduced acid-induced HCO3−secretion. Moreover, l-cysteine or the competitive AP inhibitor glycerol phosphate (10 mM) increased HCO3−secretion, inhibited by suramin. In conclusion, enhancement of the duodenal HCO3−secretory rate increased AP activity, whereas inhibition of AP activity increased the HCO3−secretory rate. These data support our hypothesis that HCO3−secretion increases AP activity by increasing local pH at its catalytic site and that AP hydrolyzes endogenous luminal phosphates, presumably ATP, which increases HCO3−secretion via activation of P2 receptors.
CD4 T cells activated in the mesenteric lymph node mediate gastrointestinal food allergy in mice
Authors: Knight Adina Kay , Blázquez Ana Belén , Zhang Shu , Mayer Lloyd , Sampson Hugh A. , Berin M. Cecilia
Published: October 2007

A localized Th2 milieu has been observed in the intestine of subjects with food allergic disorders; however, the role of T cells in the pathophysiology of these disorders remains poorly understood. Our aim was to examine sites of T cell activation in response to food challenge, identify potential factors responsible for T cell recruitment to the gut, and determine the role of T cells in disease. BALB/c mice were systemically sensitized to ovalbumin (OVA) and repeatedly fed with OVA to induce allergic diarrhea. Local cytokine and chemokine expressions were assessed by quantitative PCR, and cytokine secretion levels in the mesenteric lymph node (MLN) were determined by ELISA. Homing molecule expression was determined by flow cytometry, and the role of CD4+T cells in promoting disease was tested by adoptive transfer. Mice developed diarrhea associated with changes in epithelial ion transport, mast cell infiltration, intestinal IgE secretion, and local upregulation of Th2 cytokines and the Th2 chemokines CCL1, CCL17, and CCL22 in the small intestine. T cell activation occurred in the MLN before symptom onset, and a single feed of OVA induced T cell proliferation, α4β7upregulation, and CD62L downregulation. Cells from the MLN, including purified CD4+T cells, were able to transfer allergic diarrhea to naive mice. A gut-homing phenotype induced in the MLN and selective upregulation of Th2 chemoattractants are likely important factors in the gastrointestinal recruitment of pathological Th2-skewed CD4+T cells in food allergy.
Prostaglandin E2modulates TNF-α-induced MCP-1 synthesis in pancreatic acinar cells in a PKA-dependent manner
Authors: Sun Li-Kang , Reding Theresia , Bain Martha , Heikenwalder Mathias , Bimmler Daniel , Graf Rolf
Published: October 2007

Cyclooxygenase (COX)-2 is increased in human chronic pancreatitis. We recently demonstrated in a model of chronic pancreatitis (WBN/Kob rat) that inhibition of COX-2 activity reduces and delays pancreatic inflammation and fibrosis. Monocyte chemoattractant protein (MCP)-1 mRNA and PGE2were significantly reduced, correlating with a decreased infiltration of macrophages. MCP-1 plays an important role in the recruitment of macrophages to the site of tissue injury. The aim of our study is to identify mechanisms by which macrophages and acinar cells maintain an inflammatory reaction. The expression profile of E prostanoid receptors EP1-4and MCP-1 was analyzed by RT-PCR from pancreatic specimens and AR42J cells. MCP-1 secretion was detected by ELISA from rat pancreatic lobuli. We determined EP1-4mRNA levels in WBN/Kob rats with chronic pancreatic inflammation. Individual isoforms were highly increased in rat pancreas, concurrent with MCP-1 mRNA expression. In supernatants of pancreatic lobuli and AR42J cells, MCP-1 was detectable by ELISA. In the presence of TNF-α, MCP-1 was upregulated. Coincubation with PGE2enhanced the TNF-α-induced MCP-1 synthesis significantly. Similarly, TNF-α mRNA was synergistically upregulated by TNF-α and PGE2. Furthermore, the synergistic effect of TNF-α and PGE2was abolished by inhibition of PKA but not of PKC. We conclude that EP receptors are upregulated during chronic pancreatic inflammation. PGE2modulates the TNF-α-induced MCP-1 synthesis and secretion from acinar cells. This synergistic effect is controlled by PKA. This mechanism might explain the COX-2-dependent propagation of pancreatic inflammation.
Mechanisms of acrolein-induced myocardial dysfunction: implications for environmental and endogenous aldehyde exposure
Authors: Luo Jianzhu , Hill Bradford G. , Gu Yan , Cai Jian , Srivastava Sanjay , Bhatnagar Aruni , Prabhu Sumanth D.
Published: October 2007

Aldehydes are ubiquitous pollutants generated during the combustion of organic materials and are present in air, water, and food. Several aldehydes are also endogenous products of lipid peroxidation and by-products of drug metabolism. Despite well-documented high reactivity of unsaturated aldehydes, little is known regarding their cardiovascular effects and their role in cardiac pathology. Accordingly, we examined the myocardial effects of the model unsaturated aldehyde acrolein. In closed-chest mice, intravenous acrolein (0.5 mg/kg) induced rapid but reversible left ventricular dilatation and dysfunction. In mouse myocytes, micromolar acrolein acutely depressed myofilament Ca2+ responsiveness without altering catecholamine sensitivity, similar to the phenotype of stunned myocardium. Immunoblotting revealed increased acrolein-protein adducts and protein-carbonyls in both acrolein-exposed myocardium (1.8-fold increase, P < 0.002) and myocytes (6.4-fold increase, P < 0.02). Both the contractile dysfunction and adduct formation were markedly attenuated by pretreatment with the thiol donor N-acetylcysteine (5 mM). Two-dimensional gel electrophoresis and mass-assisted laser desorption/ionization time-of-flight mass spectrometry analysis revealed two groups of adducted proteins, sarcomeric/cytoskeletal proteins (cardiac α-actin, desmin, myosin light polypeptide 3) and energy metabolism proteins (mitochondrial creatine kinase-2, ATP synthase), indicating site-specific protein modification that was confirmed by immunohistochemical colocalization. We conclude that direct exposure to acrolein induces selective myofilament impairment, which may be, in part, related to the modification of proteins involved in myocardial contraction and energy metabolism. Myocardial dysfunction induced by acrolein and related aldehydes may be symptomatic of toxicological states associated with ambient or occupational exposures or drug toxicity. Moreover, aldehydes such as acrolein may mediate cardiac dysfunction in pathologies characterized by high-oxidative stress.
Impaired myocardial metabolic reserve and substrate selection flexibility during stress in patients with idiopathic dilated cardiomyopathy
Authors: Neglia Danilo , De Caterina Alberto , Marraccini Paolo , Natali Andrea , Ciardetti Marco , Vecoli Cecilia , Gastaldelli Amalia , Ciociaro Demetrio , Pellegrini Paola , Testa Roberto , Menichetti Luca , L'Abbate Antonio , Stanley William C. , Recchia Fabio A.
Published: October 2007

Under resting conditions, the failing heart shifts fuel use toward greater glucose and lower free fatty acid (FFA) oxidation. We hypothesized that chronic metabolic abnormalities in patients with dilated cardiomyopathy (DCM) are associated with the absence of the normal increase in myocardial glucose uptake and maintenance of cardiac mechanical efficiency in response to pacing stress. In 10 DCM patients and 6 control subjects, we measured coronary flow by intravascular ultrasonometry and sampled arterial and coronary sinus blood. Myocardial metabolism was determined at baseline, during atrial pacing at 130 beats/min, and at 15 min of recovery by infusion of [3H]oleate and [13C]lactate and measurement of transmyocardial arteriovenous differences of oxygen and metabolites. At baseline, DCM patients showed depressed coronary flow, reduced uptake and oxidation of FFA, and preferential utilization of carbohydrates. During pacing, glucose uptake increased by 106% in control subjects but did not change from baseline in DCM patients. Lactate release increased by 122% in DCM patients but not in control subjects. Cardiac mechanical efficiency in DCM patients was not different compared with control subjects at baseline but was 34% lower during stress. Fatty acid uptake and oxidation did not change with pacing in either group. Our results show that in DCM there is preferential utilization of carbohydrates, which is associated with reduced flow and oxygen consumption at rest and an impaired ability to increase glucose uptake during stress. These metabolic abnormalities might contribute to progressive cardiac deterioration and represent a target for therapeutic strategies aimed at modulating cardiac substrate utilization.
Strong galvanic vestibular stimulation obscures arterial pressure response to gravitational change in conscious rats
Authors: Abe Chikara , Tanaka Kunihiko , Awazu Chihiro , Morita Hironobu
Published: October 2007

Galvanic vestibular stimulation (GVS) is known to create an imbalance in the vestibular inputs; thus it is possible that the simultaneously applied GVS obscures adequate gravity-based inputs to the vestibular organs or modifies an input-output relationship of the vestibular system and then impairs the vestibular-mediated response. To examine this, arterial pressure (AP) response to gravitational change was examined in conscious rats with and without GVS. Free drop-induced microgravity and centrifugation-induced hypergravity were employed to elicit vestibular-mediated AP response. GVS itself induced pressor response in an intensity-dependent manner. This pressor response was completely abolished by vestibular lesion, suggesting that the GVS-induced response was mediated by the vestibular system. The pressor response to microgravity (35 ± 3 mmHg) was significantly reduced by simultaneously applied GVS (19 ± 1 mmHg), and pressor response to 3-G load was also significantly reduced by GVS. However, GVS had no effect on air jet-induced pressor response. The effects of GVS on pressor response to gravitational change were qualitatively and quantitatively similar to that caused by the vestibular lesion, effects of which were demonstrated in our previous studies (Gotoh TM, Fujiki N, Matsuda T, Gao S, Morita H. Am J Physiol Regul Integr Comp Physiol 286: R25–R30, 2004; Matsuda T, Gotoh TM, Tanaka K, Gao S, Morita H. Brain Res 1028: 140–147, 2004; Tanaka K, Gotoh TM, Awazu C, Morita H. Neurosci Lett 397: 40–43, 2006). These results indicate that GVS reduced the vestibular-mediated pressor response to gravitational change but has no effect on the non-vestibular-mediated pressor response. Thus GVS might be employed for the acute interruption of the AP response to gravitational change.
Pulmonary C-fiber receptor activation abolishes uncoupled facial nerve activity from phrenic bursting during positive end-expired pressure in the rat
Authors: Lee Kun-Ze , Fuller David D. , Lu I-Jung , Ku Li-Chi , Hwang Ji-Chuu
Published: October 2007

Phasic respiratory bursting in the facial nerve (FN) can be uncoupled from phrenic bursting by application of 9 cmH2O positive end-expired pressure (PEEP). This response reflects excitation of expiratory-inspiratory (EI) and preinspiratory (Pre-I) facial neurons during the Pre-I period and inhibition of EI neurons during inspiration (I). Because activation of pulmonary C-fiber (PCF) receptors can inhibit the discharge of EI and Pre-I neurons, we hypothesized that PCF receptor activation via capsaicin would attenuate or abolish uncoupled FN bursting with an increase from 3 cmH2O (baseline) to 9 cmH2O PEEP. Neurograms were recorded in the FN and phrenic nerve in anesthetized, ventilated, vagally intact adult Wistar rats. Increasing PEEP to 9 cmH2O resulted in a persistent rhythmic discharge in the FN during phrenic quiescence (i.e., uncoupled bursting). Combination of PEEP with intrajugular capsaicin injection severely attenuated or eliminated uncoupled bursting in the FN ( P < 0.05). Additional experiments examined the pattern of facial motoneuron (vs. neurogram) bursting during PEEP application and capsaicin treatment. These single-fiber recordings confirmed that Pre-I and EI (but not I) neurons continued to burst during PEEP-induced phrenic apnea. Capsaicin treatment during PEEP substantially inhibited Pre-I and EI neuron discharge. Finally, analyses of FN and motoneuron bursting across the respiratory cycle indicated that the inhibitory effects of capsaicin were more pronounced during the Pre-I period. We conclude that activation of PCF receptors can inhibit FN bursting during PEEP-induced phrenic apnea by inhibiting EI and I facial motoneuron discharge.
Anaerobic and aerobic relative contribution to total energy release during supramaximal effort in patients with left ventricular dysfunction
Authors: Mezzani Alessandro , Corrà Ugo , Andriani Cristina , Giordano Andrea , Colombo Roberto , Giannuzzi Pantaleo
Published: October 2007

Energetic metabolism during effort is impaired in patients with left ventricular dysfunction (Dysf), but data have been lacking up to now on the relative anaerobic vs. aerobic contribution to total energy release during supramaximal effort. Recently, the maximal accumulated oxygen deficit (MAOD) has been shown to be measurable in Dysf patients, making it possible to evaluate the anaerobic/aerobic interaction under conditions of maximal stress of both anaerobic and aerobic metabolic pathways in this population. Nineteen Dysf patients and 17 normal patients (N) underwent one ramp cardiopulmonary, three moderate-intensity constant-power, and three supramaximal constant-power (1- to 2-min, 2- to 3-min, and 3- to 4-min duration) exercise tests. MAOD was the difference between accumulated O2demand (accO2dem; estimated from the moderate-intensity O2uptake/watt relationship) and uptake during supramaximal tests. Percent anaerobic (%Anaer) and aerobic (%Aer) energetic release were [(MAOD/accO2dem)·100] and 100 − %Anaer, respectively. MAOD did not vary between 1–2, 2–3, and 3–4 min supramaximal tests, whereas accO2dem increased significantly with and was linearly related to test duration in both Dysf and N. Consequently, %Anaer and %Aer decreased and increased, respectively, with increasing test duration but did not differ between Dysf and N in 1–2 min, 2–3 min, and 3–4 min tests. Our study demonstrates a similar relative anaerobic vs. aerobic contribution to total energy release during supramaximal effort in Dysf and N. This finding indicates that energetic metabolism during supramaximal exercise is exercise tolerance independent and that relative anaerobic vs. aerobic contribution in this effort domain remains the same within the physiology- or pathology-induced limits to individual peak exercise performance.
Dexamethasone treatment of post-MI rats attenuates sympathetic innervation of the infarct region
Authors: El-Helou Viviane , Proulx Cindy , Gosselin Hugues , Clement Robert , Mimee Andrea , Villeneuve Louis , Calderone Angelino
Published: October 2007

Sympathetic fiber innervation of the damaged region following injury represents a conserved event of wound healing. The present study tested the hypothesis that impaired scar healing in post-myocardial infarction (post-MI) rats was associated with a reduction of sympathetic fibers innervating the infarct region. In 1-wk post-MI rats, neurofilament-M-immunoreactive fibers (1,116 ± 250 μm2/mm2) were detected innervating the infarct region and observed in close proximity to a modest number of endothelial nitric oxide synthase-immunoreactive scar-residing vessels. Dexamethasone (Dex) treatment (6 days) of post-MI rats led to a significant reduction of scar weight (Dex + MI 38 ± 4 mg vs. MI 63 ± 2 mg) and a disproportionate nonsignificant decrease of scar surface area (Dex + MI 0.54 ± 0.06 cm2vs. MI 0.68 ± 0.06 cm2). In Dex-treated post-MI rats, the density of neurofilament-M-immunoreactive fibers (125 ± 47 μm2/mm2) innervating the infarct region was significantly reduced and associated with a decreased expression of nerve growth factor (NGF) mRNA (Dex + MI 0.80 ± 0.07 vs. MI 1.11 ± 0.08; P < 0.05 vs. MI). Previous studies have demonstrated that scar myofibroblasts synthesize NGF and may represent a cellular target of Dex. The exposure of 1st passage scar myofibroblasts to Dex led to a dose-dependent suppression of [3H]thymidine uptake and a concomitant attenuation of NGF mRNA expression (untreated 3.47 ± 0.35 vs. Dex treated 2.28 ± 0.40; P < 0.05 vs. untreated). Thus the present study has demonstrated that impaired scar healing in Dex-treated post-MI rats was associated with a reduction of neurofilament-M-immunoreactive fibers innervating the infarct region. The attenuation of scar myofibroblast proliferation and NGF mRNA expression may represent underlying mechanisms contributing to the diminished neural response in the infarct region of Dex-treated post-MI rats.
Short-term treadmill running in the rat: what kind of stressor is it?
Authors: Brown David A. , Johnson Micah S. , Armstrong Casey J. , Lynch Joshua M. , Caruso Nicholas M. , Ehlers Lindsay B. , Fleshner Monika , Spencer Robert L. , Moore Russell L.
Published: October 2007

The use of short-term (1–5 days) treadmill running is becoming increasingly common as a model to study physiological adaptations following the exercise. Although the beneficial effects of acute exercise seem clear, a paucity of data exist describing potential markers of stress in response to forced running. We subjected male and female Sprague-Dawley rats to 0, 1, 2, 5, or 10 days of treadmill running. Twenty-four to 32 h after the last bout of exercise animals were killed and examined for training-induced changes in several physiological variables. No effect of skeletal citrate synthase activity was observed in the male animals after any duration, and only at 10 days of running did females show a significant increase in citrate synthase. Myocardial heat shock protein 72 (HSP72) content was higher in male rats than female rats, and exercise led to increased HSP72 in both sexes, although the time course was different between males and females. Animals displayed several markers of systemic stress in response to the treadmill running, and this was done in a sex-dependent manner. Serum corticosterone was significantly elevated in both sexes 24 h after exercise in three of four exercise groups. Corticosterone-binding globulin was higher in females, and decreased after running in female rats. Body and spleen weights decreased in males (but not females) in response to the exercise training, and running did not alter adrenal gland weights in either sex. These data indicate that in response to short-term treadmill running both male and female rats show signs of systemic stress, but that the pattern of changes occurs in a sex-specific manner.
Muscle fiber type-specific response of Hsp70 expression in human quadriceps following acute isometric exercise
Authors: Tupling A. R. , Bombardier E. , Stewart R. D. , Vigna C. , Aqui A. E.
Published: October 2007

To investigate the time course of fiber type-specific heat shock protein 70 (Hsp70) expression in human skeletal muscle after acute exercise, 10 untrained male volunteers performed single-legged isometric knee extensor exercise at 60% of their maximal voluntary contraction (MVC) with a 50% duty cycle (5-s contraction and 5-s relaxation) for 30 min. Muscle biopsies were collected from the vastus lateralis before (Pre) exercise in the rested control leg (C) and immediately after exercise (Post) in the exercised leg (E) only and on recovery days 1 (R1), 2 (R2), 3 (R3), and 6 (R6) from both legs. As demonstrated by Western blot analysis, whole muscle Hsp70 content was unchanged ( P > 0.05) immediately after exercise (Pre vs. Post), was increased ( P < 0.05) by ∼43% at R1, and remained elevated throughout the entire recovery period in E only. Hsp70 expression was also assessed in individual muscle fiber types I, IIA, and IIAX/IIX by immunohistochemistry. There were no fiber type differences ( P > 0.05) in basal Hsp70 expression. Immediately after exercise, Hsp70 expression was increased ( P < 0.05) in type I fibers by ∼87% but was unchanged ( P > 0.05) in type II fibers (Pre vs. Post). At R1 and throughout recovery, Hsp70 content in E was increased above basal levels ( P < 0.05) in all fiber types, but Hsp70 expression was always highest ( P < 0.05) in type I fibers. Hsp70 content in C was not different from Pre at any time throughout recovery. Glycogen depletion was observed at Post in all type II, but not type I, fibers, suggesting that the fiber type differences in exercise-induced Hsp70 expression were not related to glycogen availability. These results demonstrate that the time course of exercise-induced Hsp70 expression in human skeletal muscle is fiber type specific.
Increased Enzyme Activity and β-Adrenergic–Mediated Vasodilation in Subjects Expressing a Single-Nucleotide Variant of Human Adenylyl Cyclase 6
Authors: Gros Robert , Van Uum Stan , Hutchinson-Jaffe Adam , Ding Qingming , Pickering J. Geoffrey , Hegele Robert A. , Feldman Ross D.
Published: October 2007

Objective—

cAMP is a critical regulator of metabolic and cardiovascular function. However, the role of genetic variability in the regulation of cAMP-mediated effects is unclear. Therefore, we assessed the effect of the expression of a recently identified missense genetic variant of adenylyl cyclase isoform 6 (ADCY6 S674).

Methods and Results—

In rat vascular smooth muscle cells, gene transfer of ADCY6 S674 increased adenylyl cyclase activity and arborization to a greater extent than gene transfer of ADCY6 A674. Similarly, in adherent mononuclear leukocyte cells isolated from ADCY6 S674-expressing human subjects, both adenylyl cyclase activity and adenylyl cyclase–mediated cell retraction were significantly increased. Additionally, in dorsal hand vein LVDT studies, subjects expressing the hyper-functional ADCY6 S674 variant had significantly greater vascular sensitivity to the β-adrenergic agonist isoproterenol as assessed by both a greater potency and greater maximal effect than subjects expressing the ADCY6 A674 enzyme.

Conclusion—

These data indicate that the expression of a novel, relatively common variant of ADCY6 parallels an increase in adenylyl cyclase activity and adenylyl cyclase–mediated function in humans.
Low C1-Inhibitor Levels Predict Early Restenosis After Eversion Carotid Endarterectomy
Authors: Széplaki Gábor , Varga Lilian , Laki Judit , Dósa Edit , Rugonfalvi-Kiss Szabolcs , Madsen Hans O. , Prohászka Zoltán , Kocsis Andrea , Gál Péter , Szabó Attila , Acsády György , Karádi István , Selmeci László , Garred Peter , Füst George , Entz László
Published: October 2007

Objective—Homozygotes for the normal (A) allele of mannose-binding lectin (MBL2) gene have higher risks to develop an early restenosis after eversion carotid endarterectomy (CEA). Activation of the lectin pathway is regulated by C1-inhibitor (C1-INH). The objective of the present study was to determine the predictive value of C1-INH in restenosis after CEA.

Methods and Results—C1-INH and MBL-associated serine protease-2 (MASP-2) were determined in samples serially taken from 64 patients with CEA, who were followed-up with carotid duplex scan (CDS) examinations for 14 months.MBL2genotypes were also determined. Patients with >50% restenosis had lower C1-INH levels at 6 weeks (P=0.0052) and at 4 days (P=0.0277) postsurgery. C1-INH levels at 6 weeks correlated inversely with the CDS values at 14 months (r=−0.3415,P=0.0058), but only inMBL2A/A homozygotes (r=−0.5044,P=0.0015). Patients with low C1-INH levels (C1-INH <115%) had higher CDS values already at 7 months postsurgery. Patients withMBL2A/A and low C1-INH levels at 6 weeks postsurgery had 13.97 (95% CI:1.95 to 100.21,P=0.0087) times higher risk to develop an early restenosis. Differences in the MASP-2 concentration were not associated with restenosis.

Conclusions—Determining C1-INH levels at 6 weeks postsurgery—together with genotyping ofMBL2—might be a useful marker in the identification of patients with high risk for early carotid restenosis.
Statin Treatment and 3′ Polyadenylation of eNOS mRNA
Authors: Kosmidou Ioanna , Moore Jeffrey P. , Weber Martina , Searles Charles D.
Published: October 2007

Objective—

Statins have been shown to increase endothelial nitric oxide synthase expression via enhanced mRNA stability. Because the poly(A) tail is an important determinant of transcript stability, we sought to characterize the effect of statins on eNOS mRNA 3′ polyadenylation.

Methods and Results—

Endothelial cells treated with statins had a time- and dose-dependent increase in eNOS transcripts with long poly(A) tails (75 to 160 adenosines). This effect was dependent on 3-hydroxy-3-methylglutaryl (HMG)-coenxyme A (CoA) reductase inhibition and was observed with both lipophilic (simvastatin) and hydrophilic (rosuvastatin) statins. In mRNA stability assays, polyadenylated eNOS transcripts from statin-treated cells were 2- to 3-fold more stable than transcripts from untreated cells. The effect of statins on eNOS polyadenylation was related to cytoskeleton organization; there was increased eNOS mRNA polyadenylation after Rho inhibition and cytochalasin D treatment. Further, we found increased phosphorylation of RNA polymerase II in statin-treated cells, suggesting that statin-induced polyadenylation involved modulation of RNA polymerase II activity.

Conclusions—

Our data provide insight into a mechanism by which statins enhance eNOS mRNA stability and increase eNOS protein: statins increase eNOS mRNA polyadenylation through Rho-mediated changes in the actin cytoskeleton.
Blocking Thrombospondin-1/CD47 Signaling Alleviates Deleterious Effects of Aging on Tissue Responses to Ischemia
Authors: Isenberg Jeff S. , Hyodo Fuminori , Pappan Loretta K. , Abu-Asab Mones , Tsokos Maria , Krishna Murali C. , Frazier William A. , Roberts David D.
Published: October 2007

Objective—

Decreased blood flow secondary to peripheral vascular disease underlies a significant number of chronic diseases that account for the majority of morbidity and mortality among the elderly. Blood vessel diameter and blood flow are limited by the matricellular protein thrombospondin-1 (TSP1) through its ability to block responses to the endogenous vasodilator nitric oxide (NO). In this study we investigate the role TSP1 plays in regulating blood flow in the presence of advanced age and atherosclerotic vascular disease.

Methods and Results—

Mice lacking TSP1 or CD47 show minimal loss of their resistance to ischemic injury with age and increased preservation of tissue perfusion immediately after injury. Treatment of WT and apolipoprotein E–null mice using therapeutic agents that decrease CD47 or enhance NO levels reverses the deleterious effects of age- and diet-induced vasculopathy and results in significantly increased tissue survival in models of ischemia.

Conclusion—

With increasing age and diet-induced atherosclerotic vascular disease, TSP1 and its receptor CD47 become more limiting for blood flow and tissue survival after ischemic injury. Drugs that limit TSP1/CD47 regulation of blood flow could improve outcomes from surgical interventions in the elderly and ameliorate vascular complications attendant to aging.
Rosiglitazone Reduces Glucose-Induced Oxidative Stress Mediated by NAD(P)H Oxidase via AMPK-Dependent Mechanism
Authors: Ceolotto Giulio , Gallo Alessandra , Papparella Italia , Franco Lorenzo , Murphy Ellen , Iori Elisabetta , Pagnin Elisa , Fadini Gian Paolo , Albiero Mattia , Semplicini Andrea , Avogaro Angelo
Published: October 2007

Objective—

Hyperglycemia is the main determinant of long-term diabetic complications, mainly through induction of oxidative stress. NAD(P)H oxidase is a major source of glucose-induced oxidative stress. In this study, we tested the hypothesis that rosiglitazone (RSG) is able to quench oxidative stress initiated by high glucose through prevention of NAD(P)H oxidase activation.

Methods and Results—

Intracellular ROS were measured using the fluoroprobe TEMPO-9-AC in HUVECs exposed to control (5 mmol/L) and moderately high (10 mmol/L) glucose concentrations. NAD(P)H oxidase and AMPK activities were determined by Western blot. We found that 10 mmol/L glucose increased significantly ROS production in comparison with 5 mmol/L glucose, and that this effect was completely abolished by RSG. Interestingly, inhibition of AMPK, but not PPARγ, prevented this effect of RSG. AMPK phosphorylation by RSG was necessary for its ability to hamper NAD(P)H oxidase activation, which was indispensable for glucose-induced oxidative stress. Downstream of AMPK activation, RSG exerts antioxidative effects by inhibiting PKC.

Conclusions—

This study demonstrates that RSG activates AMPK which, in turn, prevents hyperactivity of NAD(P)H oxidase induced by high glucose, possibly through PKC inhibition. Therefore, RSG protects endothelial cells against glucose-induced oxidative stress with an AMPK-dependent and a PPARγ-independent mechanism.
IGF-1 Reduces Inflammatory Responses, Suppresses Oxidative Stress, and Decreases Atherosclerosis Progression in ApoE-Deficient Mice
Authors: Sukhanov Sergiy , Higashi Yusuke , Shai Shaw-Yung , Vaughn Charlotte , Mohler Jessica , Li Yangxin , Song Yao-Hua , Titterington Jane , Delafontaine Patrick
Published: October 2007

Objective—

Whereas growth factors, via their ability to stimulate vascular smooth muscle cell (VSMC) proliferation and migration, have been thought to play a permissive role in atherosclerosis initiation and progression, the role of insulin-like growth factor-1 (IGF-1) is unknown. Here we report for the first time that IGF-1 infusion decreased atherosclerotic plaque progression in ApoE-deficient mice on a Western diet.

Methods and Results—

ApoE-null mice (8 weeks) were infused with vehicle or recombinant human IGF-1 and fed a high-fat diet for 12 weeks. Analysis of aortic sinuses revealed that IGF-1 infusion decreased atherosclerotic plaque progression and macrophage infiltration into lesions. Furthermore, IGF-1 decreased vascular expression of the proinflammatory cytokines interleukin-6 and tumor necrosis factor-α, reduced aortic superoxide formation and urinary 8-isoprostane levels, and increased aortic pAkt and eNOS expression and circulating endothelial progenitor cells, consistent with an antiinflammatory, antioxidant, and prorepair effect on the vasculature.

Conclusions—

Our data indicate that an increase in circulating IGF-1 reduces vascular inflammatory responses, systemic and vascular oxidant stress and decreases atherosclerotic plaque progression. These findings have major implications for the treatment of atherosclerosis.
Targeted Deletion of Thioredoxin-Interacting Protein Regulates Cardiac Dysfunction in Response to Pressure Overload
Authors: Yoshioka Jun , Imahashi Kenichi , Gabel Scott A. , Chutkow William A. , Burds Aurora A. , Gannon Joseph , Schulze P. Christian , MacGillivray Catherine , London Robert E. , Murphy Elizabeth , Lee Richard T.
Published: October 2007

Biomechanical overload induces cardiac hypertrophy and heart failure, and reactive oxygen species (ROS) play a role in both processes. Thioredoxin-Interacting Protein (Txnip) is encoded by a mechanically-regulated gene that controls cell growth and apoptosis in part through interaction with the endogenous dithiol antioxidant thioredoxin. Here we show that Txnip is a critical regulator of the cardiac response to pressure overload. We generated inducible cardiomyocyte-specific and systemic Txnip-null mice (Txnip-KO) using Flp/frt and Cre/loxP technologies. Compared with littermate controls, Txnip-KO hearts had attenuated cardiac hypertrophy and preserved left ventricular (LV) contractile reserve through 4 weeks of pressure overload; however, the beneficial effects were not sustained and Txnip deletion ultimately led to maladaptive LV remodeling at 8 weeks of pressure overload. Interestingly, these effects of Txnip deletion on cardiac performance were not accompanied by global changes in thioredoxin activity or ROS; instead, Txnip-KO hearts had a robust increase in myocardial glucose uptake. Thus, deletion of Txnip plays an unanticipated role in myocardial energy homeostasis rather than redox regulation. These results support the emerging concept that the function of Txnip is not as a simple thioredoxin inhibitor but as a metabolic control protein.
Preconditioning Results in
S
-Nitrosylation of Proteins Involved in Regulation of Mitochondrial Energetics and Calcium Transport
Authors: Sun Junhui , Morgan Meghan , Shen Rong-Fong , Steenbergen Charles , Murphy Elizabeth
Published: October 2007

Nitric oxide has been shown to be an important signaling messenger in ischemic preconditioning (IPC). Accordingly, we investigated whether protein
S
-nitrosylation occurs in IPC hearts and whether
S
-nitrosoglutathione (GSNO) elicits similar effects on
S
-nitrosylation and cardioprotection. Preceding 20 minutes of no-flow ischemia and reperfusion, hearts from C57BL/6J mice were perfused in the Langendorff mode and subjected to the following conditions: (1) control perfusion; (2) IPC; or (3) 0.1 mmol/L GSNO treatment. Compared with control, IPC and GSNO significantly improved postischemic recovery of left ventricular developed pressure and reduced infarct size. IPC and GSNO both significantly increased
S
-nitrosothiol contents and
S
-nitrosylation levels of the L-type Ca
2+
channel α1 subunit in heart membrane fractions. We identified several candidate
S
-nitrosylated proteins by proteomic analysis following the biotin switch method, including the cardiac sarcoplasmic reticulum Ca
2+
-ATPase, α-ketoglutarate dehydrogenase, and the mitochondrial F1-ATPase α1 subunit. The activities of these enzymes were altered in a concentration-dependent manner by GSNO treatment. We further developed a 2D DyLight fluorescence difference gel electrophoresis proteomic method that used DyLight fluors and a modified biotin switch method to identify
S
-nitrosylated proteins. IPC and GSNO produced a similar pattern of
S
-nitrosylation modification and cardiac protection against ischemia/reperfusion injury, suggesting that protein
S
-nitrosylation may play an important cardioprotective role in heart.
Magnetic Resonance–Based Anatomical Analysis of Scar-Related Ventricular Tachycardia
Authors: Ashikaga Hiroshi , Sasano Tetsuo , Dong Jun , Zviman M. Muz , Evers Robert , Hopenfeld Bruce , Castro Valeria , Helm Robert H. , Dickfeld Timm , Nazarian Saman , Donahue J. Kevin , Berger Ronald D. , Calkins Hugh , Abraham M. Roselle , Marbán Eduardo , Lardo Albert C. , McVeigh Elliot R. , Halperin Henry R.
Published: October 2007

In catheter ablation of scar-related monomorphic ventricular tachycardia (VT), substrate voltage mapping is used to electrically define the scar during sinus rhythm. However, the electrically defined scar may not accurately reflect the anatomical scar. Magnetic resonance–based visualization of the scar may elucidate the 3D anatomical correlation between the fine structural details of the scar and scar-related VT circuits. We registered VT activation sequence with the 3D scar anatomy derived from high-resolution contrast-enhanced MRI in a swine model of chronic myocardial infarction using epicardial sock electrodes (n=6, epicardial group), which have direct contact with the myocardium where the electrical signal is recorded. In a separate group of animals (n=5, endocardial group), we also assessed the incidence of endocardial reentry in this model using endocardial basket catheters. Ten to 12 weeks after myocardial infarction, sustained monomorphic VT was reproducibly induced in all animals (n=11). In the epicardial group, 21 VT morphologies were induced, of which 4 (19.0%) showed epicardial reentry. The reentry isthmus was characterized by a relatively small volume of viable myocardium bound by the scar tissue at the infarct border zone or over the infarct. In the endocardial group (n=5), 6 VT morphologies were induced, of which 4 (66.7%) showed endocardial reentry. In conclusion, MRI revealed a scar with spatially complex structures, particularly at the isthmus, with substrate for multiple VT morphologies after a single ischemic episode. Magnetic resonance–based visualization of scar morphology would potentially contribute to preprocedural planning for catheter ablation of scar-related, unmappable VT.
Reversed Robin Hood Syndrome in Acute Ischemic Stroke Patients
Authors: Alexandrov Andrei V. , Sharma Vijay K. , Lao Annabelle Y. , Tsivgoulis Georgios , Malkoff Marc D. , Alexandrov Anne W.
Published: October 2007

Background and Purpose—

Recurrent hemodynamic and neurological changes with persisting arterial occlusions may be attributable to cerebral blood flow steal from ischemic to nonaffected brain.

Methods—

Transcranial Doppler monitoring with voluntary breath-holding and serial NIH Stroke Scale (NIHSS) scores were obtained in patients with acute middle cerebral artery or internal carotid artery occlusions. The steal phenomenon was detected as transient, spontaneous, or vasodilatory stimuli-induced velocity reductions in affected arteries at the time of velocity increase in normal vessels. The steal magnitude (%) was calculated as [(MFVm−MFVb)/MFVb]×100, where m=minimum and b=baseline mean flow velocities (MFV) during the 15- to 30-second period of a total 30 second of breath-holding.

Results—

Six patients had steal phenomenon on transcranial Doppler (53 to 73 years, NIHSS 4 to 15 points). Steal magnitude ranged from −15.0% to −43.2%. All patients also had recurrent neurological worsening (>2 points increase in NIHSS scores) at stable blood pressure. In 3 of 5 patients receiving noninvasive ventilatory correction for snoring/sleep apnea, no further velocity or NIHSS score changes were noted.

Conclusions—

Our descriptive study suggests possibility to detect and quantify the cerebral steal phenomenon in real-time. If the steal is confirmed as the cause of neurological worsening, reversed Robin Hood syndrome may identify a target group for testing blood pressure augmentation and noninvasive ventilatory correction in stroke patients.
Stroke Incidence, Prognosis, 30-Day, and 1-Year Case Fatality Rates in Matão, Brazil
Authors: Minelli Cesar , Fu Fen Lee , Camara Minelli Denise P.
Published: October 2007

Background and Purpose—

Stroke is the main cause of death in Brazil and no prospective population-based study has been conducted in the country. The purpose of this study was to determine the incidence of stroke, stroke subtypes, case fatality, and prognosis after 1 year of follow-up in the city of Matão, Brazil.

Methods—

Using overlapping methods of case ascertainment, all stroke cases that occurred in the city of Matão (population, 75 053) from November 1, 2003 to October 31, 2004 were followed-up at 1 month and 1 year after the episode. Standard criteria for population-based stroke studies were followed.

Results—

Of 141 suspect stroke cases identified, 81 were first-ever-in-a-lifetime strokes. All patients underwent a CT scan. The crude annual incidence rate per 100 000 per year was 108 (95% CI, 85.7–134.1) and the rate adjusted for sex and age to the Segi population was 137 (95% CI, 112.0 to 166.4) per 100 000 inhabitants per year. Ischemic stroke occurred in 69 (85.2%) subjects, intracerebral hemorrhage in 11 (13.6%), and subarachnoid hemorrhage in 1 (1.2%). The 30-day case fatality rate was 18.5 and the 1-year case fatality rate was 30.9%. After 1 year of follow-up, 43% of the patients were independent in activities of daily living, 49.4% had independent gait, and 15.9% had a recurrent stroke.

Conclusions—

The present results are similar to those obtained in other stroke population-based studies. Future studies in Matão will provide the opportunity to discover ways to decrease the stroke burden in Brazil.
Carnosine Is Neuroprotective Against Permanent Focal Cerebral Ischemia in Mice
Authors: Rajanikant G.K. , Zemke Daniel , Senut Marie-Claude , Frenkel Mark B. , Chen Alex F. , Gupta Rishi , Majid Arshad
Published: October 2007

Background and Purpose—

Carnosine is a naturally occurring dipeptide with multiple neuroprotective properties. In addition, it is well tolerated in high doses with minimal side effects. The purposes of this study were to determine whether carnosine is neuroprotective in permanent focal cerebral ischemia and to determine potential mechanisms of neuroprotection.

Methods—

We investigated the efficacy of carnosine in a mouse model of permanent focal cerebral ischemia. The effects of carnosine were investigated with respect to neuronal damage and infarct formation, endogenous antioxidant status, and matrix metalloproteinase activity.

Results—

Carnosine significantly decreased infarct size and neuronal damage when administered at time points both before and after the induction of ischemia. Carnosine also decreased reactive oxygen species levels in the ischemic brain, preserved normal glutathione levels, and decreased matrix metalloproteinase protein levels and activity.

Conclusions—

Carnosine is neuroprotective in focal cerebral ischemia and appears to influence deleterious pathological processes that are activated after the onset of ischemia.
Novel End Point Analytic Techniques and Interpreting Shifts Across the Entire Range of Outcome Scales in Acute Stroke Trials
Authors: Saver Jeffrey L.
Published: October 2007

Background and Purpose—

Stroke treatments are generally not curative, but rather alter patient outcome over the entire range of functional measures. Dichotomizing outcome scales reduces computational complexity, but discards substantial outcome information, artificially privileges only a single health state transition as clinically meaningful, and often reduces study power. Newer approaches to endpoint analysis have several advantageous properties.

Summary of Review—

The global statistic assesses treatment effects on multiple outcome measures simultaneously. However, translating the global statistic multidimensional vector effect at the population level into benefit or harm expected in the individual patient is problematic. Responder analysis adjusts outcome thresholds to patient stroke severity at study entry, identifying achievable goals for each patient. However, responder analysis still discards substantial outcome information. Shift analysis gauges change in outcome distributions over the full range of ascertained outcomes, incorporating benefit and harm at all health state transitions valued by patients and clinicians, and often increasing study power. Translation of findings of shift analyses into clinically accessible terms may be accomplished using the recently developed joint outcome table specification technique, which yields the following values for the number needed to treat for 1 patient to improve in a clinically important manner: nimodipine in subarachnoid hemorrhage, 6.8; coiling over clipping, 5.9; intra-arterial pro-urokinase in acute cerebral ischemia, 4.8; intravenous tissue plasminogen activator, 3.3.

Conclusions—

Dichotomized, global statistic, responder, and shift analyses each offer distinctive benefits and drawbacks. Choice of primary end point analytic technique should be tailored to the study population, expected treatment response, and study purpose. Shift analysis generally provides the most comprehensive index of a treatment’s clinical impact.