Shu-ichi Saitoh

Impact of adaptive servo‐ventilation on cardiovascular function and prognosis in heart failure patients with preserved left ventricular ejection fraction and sleep‐disordered breathing

Effective pharmacotherapy for heart failure with preserved left ventricular ejection fraction (HFpEF) is still unclear. Sleep‐disordered breathing (SDB) causes cardiovascular dysfunction, giving rise to factors involved in HFpEF. However, it remains unclear whether adaptive servo‐ventilation (ASV) improves cardiovascular function and long‐term prognosis of patients with HFpEF and SDB.

Role of LOX‐1 in monocyte adhesion‐triggered redox, Akt/eNOS and Ca2+ signaling pathways in endothelial cells

This study was conducted to examine the role of lectin‐like oxidized low‐density lipoprotein receptor‐1 (LOX‐1) in monocyte adhesion‐induced redox‐sensitive, Akt/eNOS and Ca2+ signaling pathways in endothelial cells (ECs). LOX‐1 was blocked by an antibody‐neutralizing LOX‐1 TS92 or small interfering RNA. In cultured human aortic ECs, monocyte adhesion activated Rac1 and p47phox, and increased NADPH oxidase activity and reactive oxygen species (ROS) generation within 30 min and NF‐κB phosphorylation within 1 h, resulting in redox‐sensitive gene expression. Akt and eNOS phosphorylation was induced 15 min after adding monocytes and returned to control level after 30 min, whereas NO production was not altered by monocyte adhesion. Blockade of LOX‐1 blunted the monocyte adhesion‐triggered redox‐sensitive signaling pathway and Akt/eNOS phosphorylation in ECs. Both endothelial intracellular Ca2+ mobilization and Ca2+ influx caused by monocyte attachment were markedly attenuated by pretreatment of ECs with TS92. This suggests that LOX‐1 is involved in redox‐sensitive, Akt/eNOS and Ca2+ signaling pathways in monocyte adhesion to ECs independent of oxidized low‐density lipoprotein (ox‐LDL). Furthermore, blockade of Ca2+ inhibited monocyte adhesion‐triggered Rac1 and p47phox activation and ROS generation in ECs, whereas Ca2+ signaling was suppressed by blockade of NADPH oxidase and ROS generation. Finally, TS92 blocked the monocyte adhesion to ECs stimulated with or without tumor necrosis factor‐α or ox‐LDL. We provide evidence that LOX‐1 plays a role in redox‐sensitive, Akt/eNOS and Ca2+ signaling pathways in monocyte adhesion to ECs independent of the ox‐LDL–LOX‐1 axis. J. Cell. Physiol. 220: 706–715, 2009.

Cilostazol, a novel cyclic AMP phosphodiesterase inhibitor, prevents reocclusion after coronary arterial thrombolysis with recombinant tissue-type plasminogen activator.

Inhibitors of cyclic nucleotide phosphodiesterase hydrolysis of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate are known to inhibit platelet aggregation, which plays an important role in acute reocclusion after thrombolysis in acute myocardial infarction. In the present study of a canine preparation of coronary artery thrombosis superimposed on high-grade stenosis, we tested whether the antithrombotic agent cilostazol, an inhibitor of cAMP phosphodiesterase, could prevent acute reocclusion or sustain coronary blood flow after thrombolysis when used with recombinant tissue-type plasminogen activator (rt-PA) and heparin. Intravenous infusion of rt-PA (0.5 mg/kg body wt for 30 minutes) and heparin (a 150 IU/kg body wt i.v. bolus and then 25 IU/kg body wt per hour i.v.) was combined with cilostazol (0.6 or 1.8 mg/kg body wt for 60 minutes). Without cilostazol, reperfusion was observed in seven of eight dogs, but reocclusion occurred in six of these seven dogs after 9 +/- 2 minutes. After administration of 1.8 mg/kg body wt cilostazol (group B-2; a 120-minute observation after the start of rt-PA infusion), reperfusion occurred in all seven dogs (p < 0.05 versus control group), and brief cyclic reocclusion was observed in only one dog 63 minutes after reperfusion. At the same dose of cilostazol (group B-2L; a 240-minute observation after the start of rt-PA infusion), reperfusion occurred in all five dogs (p < 0.05 versus control group), and coronary blood flow was well maintained except for one short reocclusion in one dog. Cilostazol inhibited cyclic flow reduction in a dose-dependent fashion.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute heart failure volume control multicenter randomized (AVCMA) trial: comparison of tolvaptan and carperitide.

Acute decompensated heart failure (ADHF) is a common and highly morbid cardiovascular disorder. Diuresis is a major therapy for the reduction of congestive symptoms. However, most diuretics cause hyponatremia, which is a worsening factor of ADHF patients prognosis. The purpose of this study was to examine the efficacy and safety of tolvaptan, which is a selective vasopressin V2 receptor antagonist and produces water excretion without changes in sodium excretion, compared with carperitide.

Multiple endothelial injury in epicardial coronary artery induces downstream microvascular spasm as well as remodeling partly via thromboxane A2.

OBJECTIVES The study was undertaken to develop a coronary microvascular spasm model in pigs by repeated epicardial coronary artery endothelial injury. BACKGROUND The pathophysiologic mechanisms responsible for coronary microvascular spasm remain unclear, in large part because a suitable animal model has yet to be found. METHODS Balloon endothelial denudation was done just distal to the site of an implanted Doppler flowmeter in the left anterior descending coronary artery (LAD) every two weeks for a total of four times. Changes in LAD blood flow by intracoronary administration of vasoactive agents were assessed before each denudation. RESULTS In the epicardial LAD endothelial denudation pigs, decreases in LAD blood flow caused by acetylcholine were augmented. Before denudation, it was - 15 +/- 4%, and at week 8 (i.e., two weeks after the fourth denudation) it was -100% (i.e., zero flow [p < 0.01]). The LAD flow changes in response to 5-hydroxytryptamine (5-HT) changed from an increase to a decrease, accompanied by medial thickening of microvessels in the LAD perfusion area. These flow responses were observed without significant changes in LAD diameter. In contrast, the LAD blood flow responses to acetylcholine and 5-HT did not change throughout the experiment in pigs given aspirin and a thromboxane A2 (TXA2) synthase inhibitor orally. CONCLUSIONS This microvascular spasm model indicates that hypersensitivity to vasoactive substances in the microvascular beds as well as microvascular remodeling are brought about partly through TXA2. This model should be useful for examining the pathophysiology and treatment of microvascular angina.

Adaptive servo ventilation improves Cheyne-Stokes respiration, cardiac function, and prognosis in chronic heart failure patients with cardiac resynchronization therapy

BACKGROUND Cheyne-Stokes respiration (CSR-CSA) is often observed in patients with chronic heart failure (CHF). Although cardiac resynchronization therapy (CRT) is effective for CHF patients with left ventricular dyssynchrony, it is still unclear whether adaptive servo ventilation (ASV) improves cardiac function and prognosis of CHF patients with CSR-CSA after CRT. METHODS AND RESULTS Twenty two patients with CHF and CSR-CSA after CRT defibrillator (CRTD) implantation were enrolled in the present study and randomly assigned into two groups: 11 patients treated with ASV (ASV group) and 11 patients treated without ASV (non-ASV group). Measurement of plasma B-type natriuretic peptide (BNP) levels (before 3, and 6 months later) and echocardiography (before and 6 months) were performed in each group. Patients were followed up to register cardiac events (cardiac death and re-hospitalization) after discharge. In the ASV group, indices for apnea-hypopnea, central apnea, and oxyhemoglobin saturation were improved on ASV. BNP levels, cardiac systolic and diastolic function were improved with ASV treatment for 6 months. Importantly, the event-free rate was significantly higher in the ASV group than in the non-ASV group. CONCLUSIONS ASV improves CSR-CSA, cardiac function, and prognosis in CHF patients with CRTD. Patients with CSR-CSA and post CRTD implantation would get benefits by treatment with ASV.

Preventive effects of pravastatin on thrombin-triggered vascular responses via Akt/eNOS and RhoA/Rac1 pathways in vivo

AIMS Small GTPases RhoA and Rac1 play crucial roles in endothelial dysfunction and reactive oxygen species (ROS) generation. We reported evidence that in thrombin-stimulated endothelial cells, rapid geranylgeranylation is an essential process for full activation of unprocessed RhoA, which is blocked by statin. In this study, we examined the effects of intravenous administration of pravastatin on thrombin-triggered vascular responses in vivo, as well as on the lipid modification of unprocessed forms of RhoA and Rac1 and their activation induced by thrombin. METHODS AND RESULTS Thrombin (50 U/kg) was intravenously injected with or without 0.3 mg/kg pravastatin into Wistar and spontaneously hypertensive rats. Coadministration of pravastatin prevented thrombin-induced impaired endothelium-dependent coronary vasodilation and down-regulated Akt/endothelial nitric oxide synthase (eNOS) phosphorylation within 1 h, as well as the down-regulation of eNOS protein expression within 4 h. In addition, thrombin increased Rac1/p47(phox)-dependent NAD(P)H oxidase activities of rat aortas within 1 h, resulting in ROS generation, which was prevented by the coadministration of pravastatin. Furthermore, the coadministration of pravastatin prevented thrombin-induced conversion of unprocessed RhoA and Rac1 into the geranylgeranylated forms as well as GTP-loading and membrane translocation within 1 h. CONCLUSION Intravenous injection of pravastatin prevents impaired NO-dependent vasodilation and Rac1/NAD(P)H oxidase-mediated-ROS generation by blocking the down-regulation of Akt/eNOS pathways and the full activation of unprocessed RhoA and Rac1 in vivo.

Morphological and functional changes in coronary vessel evoked by repeated endothelial injury in pigs

OBJECTIVE We examined the morphological changes induced by repeated endothelial denudation in coronary artery (CA), as well as functional changes in the endothelium-dependent and smooth muscle responses to various vasoactive agents during the process of intimal thickening. METHODS We observed vascular responses in denuded and non-denuded portions of pig CA while being fed a normal diet (n = 11, N group) or 2% cholesterol diet (n = 25, C group) to intracoronary acetylcholine (ACh), 5-hydroxytryptamine (5-HT), substance P (SP), and isosorbide dinitrate (ISDN) with and without the nitric oxide synthesis inhibitor N omega-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg i.v.) over a period of 8 weeks. Balloon endothelial denudation of the left anterior descending CA was carried out every 2 weeks. RESULTS In N group, maximum vasoconstriction was obtained with ACh 2 weeks after the first denudation [26 +/- 5% vs. 1 +/- 1% pre-denudation, p < 0.05]. L-NAME did not affect ACh-induced CA diameter changes. Thereafter, the response to ACh was attenuated by repeated denudation in N groups. However, the degree of 5-HT-induced CA narrowing at the denuded portion increased from 7 +/- 4% (0 week) to 88 +/- 8% (8 weeks) (p < 0.05). The changes resulted in severe myocardial ischaemia, and suggested that endothelium-dependent vasodilation was progressively attenuated while hyperreactivity of vascular smooth muscle simultaneously increased. Vasodilation induced by SP was attenuated somewhat, but ISDN-induced vasodilation was preserved. Although mild hypercholesterolaemia was induced in C group, the vascular responses to these vasoactive agents did not differ from those of N group. CONCLUSIONS Repeated CA endothelial injury and regeneration induce the change of morphology and vascular reactivity in the denuded portion regardless of atherogenic diet. This study strongly suggests that intimal thickening caused by repeated endothelial injury and regeneration induces specific vascular responses to vasoactive agents. Moreover, it is also suggested that during the progression of intimal thickening, increased vascular smooth muscle contraction and decreased endothelium-dependent dilation appear in a stimulus-dependent manner, often leading to severe coronary vasoconstriction accompanied with definitive ECG ST change.

Liver Dysfunction Assessed by Model for End-Stage Liver Disease Excluding INR (MELD-XI) Scoring System Predicts Adverse Prognosis in Heart Failure

Aims Liver dysfunction due to heart failure (HF) is often referred to as cardiac or congestive hepatopathy. The composite Model for End-Stage Liver Disease excluding INR (MELD-XI) is a robust scoring system of liver function, and a high score is associated with poor prognosis in advanced HF patients with a heart transplantation and/or ventricular assist device. However, the impact of MELD-XI on the prognosis of HF patients in general remains unclear. Methods and Results We retrospectively analyzed 562 patients who were admitted to our hospital for the treatment of decompensated HF. A MELD-XI score was graded, and patients were divided into two groups based on the median value of MELD-XI score: Group L (MELD-XI <10, n = 289) and Group H (MELD-XI ≥10, n = 273). We compared all-cause mortality and echocardiographic findings between the two groups. In the follow-up period (mean 471 days), 104 deaths (62 cardiac deaths and 42 non-cardiac deaths) were observed. The event (cardiac death, non-cardiac death, all-cause death)-free rate was significantly higher in group L than in group H (logrank P<0.05, respectively). In the Cox proportional hazard analysis, a high MELD-XI score was found to be an independent predictor of cardiac deaths and all-cause mortality in HF patients. Regarding echocardiographic parameters, right atrial and ventricular areas, inferior vena cava diameter, and systolic pulmonary artery pressure were higher in group H than in group L (P<0.05, respectively). Conclusions The MELD-XI scoring system, a marker of liver function, can identify high-risk patients with right heart volume overload, higher pulmonary arterial pressure and multiple organ failure associated with HF.

Clinical features of patients with decompensated heart failure after the Great East Japan Earthquake.

The occurrence of heart failure (HF) and its clinical features after a great disaster have not been rigorously examined. We retrospectively examined the effect of the Great East Japan Earthquake on the occurrence of decompensated HF. The number of patients admitted for treatment of decompensated HF and their clinical features were compared between 2 periods, March 11, 2011 to September 10, 2011 (after the earthquake) and the same period in the previous year. The number of admissions increased from 55 in 2010 to 84 in 2011. A comparison of the clinical features showed that the patients admitted after the earthquake had (1) older age (p = 0.031), (2) greater systolic blood pressure (p = 0.039), (3) a greater incidence of new-onset HF due to valvular heart disease (p = 0.040), (4) interruption of drugs (p = 0.001), (5) a greater incidence of infection (p = 0.019), (6) greater B-type natriuretic peptide (p = 0.005) and C-reactive protein (p = 0.003) levels, (7) a lower estimated glomerular filtration rate (p = 0.048) and lower albumin levels (p = 0.021), and (8) a larger diameter of the inferior vena cava (p = 0.008). In conclusion, these results suggest that the earthquake increased the incidence of HF in association with high blood pressure, interruption of drugs, inflammation, malnutrition, and fluid retention. Taking appropriate measures to control blood pressure, nutritional status, and hygiene environment might decrease the occurrence of HF in future disasters.