Airway hyperresponsiveness induced by repeated esophageal infusion of HCl in guinea pigs.

Gastroesophageal reflux is a common disorder closely related to chronic airway diseases, such as chronic cough, asthma, chronic bronchitis, and chronic obstructive disease. Indeed, gastroesophageal acid reflux into the respiratory tract causes bronchoconstriction, but the underlying mechanisms have still not been clarified. This study aimed to elucidate functional changes of bronchial smooth muscles (BSMs) isolated from guinea pigs in an animal model of gastroesophageal reflux. The marked airway inflammation, hyperresponsiveness and remodeling were observed after guinea pigs were exposed to intraesophageal HCl infusion for 14 days. In addition, contractile responses to acetylcholine (ACh), KCl, electrical field stimulation, and extracellular Ca(2+) were greater in guinea pigs infused with HCl compared with control groups. The L-type voltage-dependent Ca(2+) channels (L-VDCC) blocker, nicardipine, significantly inhibited ACh- and Ca(2+)-enhanced BSM contractions in guinea pigs infused with HCl. The Rho-kinase inhibitor, Y27632, attenuated ACh-enhanced BSM contractions in guinea pigs infused with HCl. Moreover, mRNA and protein expressions for muscarinic M2 and M3 receptors, RhoA, and L-VDCC in BSM were detected by real-time PCR and Western blot. Expressions of mRNA and protein for muscarinic M3 receptors, RhoA, and L-VDCC were greater than in BSM of HCl-infused guinea pigs, whereas levels of muscarinic M2 receptors were unchanged. We demonstrate that acid infusion to the lower esophagus and, subsequently, microaspiration into the respiratory tract in guinea pigs leads to airway hyperresponsiveness and overactive BSM. Functional and molecular results indicate that overactive BSM is the reason for enhancement of extracellular Ca(2+) influx via L-VDCC and Ca(2+) sensitization through Rho-kinase signaling.

The role of cardiac pacing in carotid sinus syndrome: a meta-analysis.

PURPOSE: Cardiac pacing can be used to treat carotid sinus syndrome (CSS), but clinical studies have shown conflicting results. We conducted a systematic review and meta-analysis to evaluate the role of pacing for CSS. METHODS: A systematic search of publications in PubMed, Embase, and the Cochrane Library without language restriction was performed. Prospective randomized studies that compared cardiac pacing with standard therapy or pacing with different algorithms were included if the recurrence of syncope or the number of falls was observed. RESULTS: Eight studies enrolling 540 patients were identified. In open-label studies, the recurrence of syncope was reduced significantly by cardiac pacing compared with standard therapy. The recurrence of syncope was not different between single- and dual-chamber pacing, but a lower rate of patients with pre-syncope was observed in the group with dual-chamber pacing. Double-blind clinical studies failed to observe the role of cardiac pacing for preventing falls in patients with CSS. CONCLUSION: The results of meta-analysis supported the use of cardiac pacing for patients with dominant cardioinhibitory CSS.

Relationships between use of statins and arterial stiffness in normotensive and hypertensive patients with coronary artery disease.

BACKGROUND: Statins improve arterial stiffness in patients with coronary artery disease (CAD). Hypertension is a predominant contributor of arterial stiffening. However, the influence of hypertension on the effect of statins for improving arterial stiffness in CAD patients has seldom been investigated. Therefore, in this study, we investigated the relationships between statin use and arterial stiffness in normotensive and hypertensive CAD patients. METHODS: Brachial-ankle pulse wave velocity (ba-PWV) was measured in 437 patients, including 220 hypertensive CAD patients (121 used statins, 99 did not) and 217 normotensive CAD patients (105 used statins, 112 did not). The normotensive and hypertensive CAD patients were matched according to age, sex, and body mass index (BMI). RESULTS: In the normotensive and hypertensive CAD patients, lipid profiles were significantly improved in the statin group compared with the non-statin group. No significant differences in the administered statins (i.e., atorvastatin, simvastatin, rosuvastatin, and pravastatin) and statin therapy duration were found between normotensive and hypertensive CAD patients (all P > 0.05). No significant correlation of ba-PWV and statin therapy duration was found in all CAD patients, normotensive CAD patients, or hypertensive CAD patients (all P > 0.05). ba-PWV in the statin group was significantly lower than that in the non-statin group in normotensive CAD patients ((1331.68 ± 167.52) cm/s vs. (1468.61 ± 244.54) cm/s, P = 0.002) but not in hypertensive CAD patients (P > 0.05). In multiple linear regression analyses, statin therapy was significantly associated with ba-PWV after adjusting for confounding variables in normotensive CAD patients (P = 0.018) but not in hypertensive CAD patients (P > 0.05). CONCLUSIONS: Statins may significantly improve arterial stiffness in CAD patients, and hypertension may probably influence the effectiveness of statin therapy in improving arterial stiffness in this population. Further studies are required to investigate the effect of statins on arterial stiffness in normotensive and hypertensive CAD patients.