Distribution of osteoprotegerin in unruptured intracranial aneurysms in humans: association with aneurysm wall protective remodeling

OBJECTIVE

Aneurysm wall inflammation is associated with lesion instability in unruptured intracranial aneurysms (UIAs). However, most UIAs remain unruptured during lifelong follow-ups because of simultaneous protective remodeling against the inflammatory response. The protective effects of osteoprotegerin (OPG) in intracranial and abdominal aortic aneurysms have been suggested using rodent models; however, the role of this protein in UIAs in humans remains unclear. Herein, the authors examined the relationship between OPG expression and aneurysm wall integrity in intraoperatively resected UIAs by using immunohistochemical and immunofluorescence staining.

METHODS

Sixteen UIA wall tissue specimens resected between 2017 and 2022 were analyzed. Aneurysm growth was defined as an enlargement > 1 mm or an obvious morphological change over the course of more than 6 months. Three high-power fields were randomly selected from areas expressing high and low levels of OPG within the same aneurysm. To clarify the role of OPG in the human aneurysm wall, the authors compared averaged values for the following pathological features between the 2 OPG expression groups: aneurysm wall thickness, collagen, macrophages, smooth muscle cells, and transforming growth factor beta 1 (TGF-β1). Immunohistochemical staining within the entire tissue area was also analyzed to determine the relationships between OPG expression and different aneurysm growth patterns. Pathological findings were compared between high and low OPG expression levels using the Wilcoxon signed-rank test.

RESULTS

The heterogeneous expression of OPG was detected in the walls of UIAs. Lesions expressing high OPG levels had thicker aneurysm walls (327 vs 180 μm, p = 0.002) and higher expression levels of TGF-β1 (8.5% vs 5.4%, p = 0.002) than those expressing low OPG levels. The expression of TGF-β1 was colocalized with that of OPG mainly in the tunica media. Furthermore, lesions expressing high OPG levels had larger α-SMA+ areas (25% vs 13%, p = 0.002). Aneurysm growth was observed in 6 of 9 UIAs with available data: whole sac expansion in 4 and secondary aneurysm formation in 2. Among the 6 UIAs with aneurysm growth, OPG expression was relatively higher in the UIAs with an internal elastic lamina than in those without (17% vs 6.9%).

CONCLUSIONS

Aneurysm wall integrity was associated with OPG expression in the aneurysm wall. Collectively, the study results indicated that OPG is associated with protective remodeling, which may contribute to the retention of aneurysm wall structures.

A possible role for proinflammatory activation via cGAS-STING pathway in atherosclerosis induced by accumulation of DNA double-strand breaks

DNA damage contributes to atherosclerosis. However, causative links between DNA double-strand breaks (DSBs) and atherosclerosis have yet to be established. Here, we investigated the role of DSBs in atherosclerosis using mice and vascular cells deficient in Ku80, a DSB repair protein. After 4 weeks of a high-fat diet, Ku80-deficient apolipoprotein E knockout mice (Ku80+/-ApoE-/-) displayed increased plaque size and DSBs in the aorta compared to those of ApoE-/- control. In the preatherosclerotic stages (two-week high-fat diet), the plaque size was similar in both the Ku80+/-ApoE-/- and ApoE-/- control mice, but the number of DSBs and mRNA levels of inflammatory cytokines such as IL-6 and MCP-1 were significantly increased in the Ku80+/-ApoE-/- aortas. We further investigated molecular links between DSBs and inflammatory responses using vascular smooth muscle cells isolated from Ku80 wild-type and Ku80+/- mice. The Ku80+/- cells displayed senescent features and elevated levels of inflammatory cytokine mRNAs. Moreover, the cytosolic DNA-sensing cGAS-STING pathway was activated in the Ku80+/- cells. Inhibiting the cGAS-STING pathway reduced IL-6 mRNA level. Notably, interferon regulatory factor 3 (IRF3), a downstream effector of the cGAS-STING pathway, was activated, and the depletion of IRF3 also reduced IL-6 mRNA levels in the Ku80+/- cells. Finally, DSBs accumulation in normal cells also activated the cGAS-STING-IRF3 pathway. In addition, cGAS inhibition attenuated DNA damage-induced IL-6 expression and cellular senescence in these cells. These results suggest that DSBs accumulation promoted atherosclerosis by upregulating proinflammatory responses and cellular senescence via the cGAS-STING (-IRF3) pathway.

Angiotensin II Type 1 Receptor Blocker Prevents Abdominal Aortic Aneurysm Progression in Osteoprotegerin-Deficient Mice via Upregulation of Angiotensin (1-7)

Background Angiotensin II type 1 receptor blockers (ARBs) have been shown to limit the growth of abdominal aortic aneurysm (AAA), but their efficacy is controversial. This study aimed to investigate the molecular mechanism underlying the protective effect of ARBs against AAA progression. Methods and Results Olmesartan, an ARB, was administered to wild-type and osteoprotegerin-knockout (Opg-KO) mice starting 2 weeks before direct application of CaCl₂ to aortas to induce AAA. The protective effect of olmesartan against AAA in wild-type and Opg-KO mice was compared at 6 weeks after AAA induction. Olmesartan prevented AAA progression in Opg-KO mice, including excessive aortic dilatation and collapse of tunica media, but not in wild-type mice. Deficiency of the Opg gene is known to cause excessive activation of the tumor necrosis factor-related apoptosis-inducing ligand-induced c-Jun N-terminal kinase/matrix metalloproteinase 9 pathway, resulting in prolonged AAA progression. Olmesartan attenuated the upregulation of phosphorylated c-Jun N-terminal kinase and matrix metalloproteinase 9 expression in the aortic wall of Opg-KO mice. In cultured vascular smooth muscle cells, tumor necrosis factor-related apoptosis-inducing ligand-induced c-Jun N-terminal kinase phosphorylation and matrix metalloproteinase 9 expression were inhibited by angiotensin (1-7), the circulating levels of which are increased by ARBs. Furthermore, administering an angiotensin (1-7) antagonist to Opg-KO mice diminished the protective effect of olmesartan against AAA progression. Conclusions Olmesartan prevented AAA progression in Opg-KO mice by upregulating angiotensin (1-7), suggesting that angiotensin (1-7) may be a key factor that mediates the protective effect of ARBs.

Cigarette smoke induces mitochondrial DNA damage and activates cGAS-STING pathway: application to a biomarker for atherosclerosis

Cigarette smoking is a major risk factor for atherosclerosis. We previously reported that DNA damage was accumulated in atherosclerotic plaque, and was increased in human mononuclear cells by smoking. As vascular endothelial cells are known to modulate inflammation, we investigated the mechanism by which smoking activates innate immunity in endothelial cells focusing on DNA damage. Furthermore, we sought to characterize the plasma level of cell-free DNA (cfDNA), a result of mitochondrial and/or genomic DNA damage, as a biomarker for atherosclerosis. Cigarette smoke extract (CSE) increased DNA damage in the nucleus and mitochondria in human endothelial cells. Mitochondrial damage induced minority mitochondrial outer membrane permeabilization, which was insufficient for cell death but instead led to nuclear DNA damage. DNA fragments, derived from the nucleus and mitochondria, were accumulated in the cytosol, and caused a persistent increase in IL-6 mRNA expression via the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway. cfDNA, quantified with quantitative PCR in culture medium was increased by CSE. Consistent with in vitro results, plasma mitochondrial cfDNA (mt-cfDNA) and nuclear cfDNA (n-cfDNA) were increased in young healthy smokers compared with age-matched nonsmokers. Additionally, both mt-cfDNA and n-cfDNA were significantly increased in patients with atherosclerosis compared with the normal controls. Our multivariate analysis revealed that only mt-cfDNA predicted the risk of atherosclerosis. In conclusion, accumulated cytosolic DNA caused by cigarette smoke and the resultant activation of the cGAS-STING pathway may be a mechanism of atherosclerosis development. The plasma level of mt-cfDNA, possibly as a result of DNA damage, may be a useful biomarker for atherosclerosis.

S-1-Propenylcysteine promotes IL-10-induced M2c macrophage polarization through prolonged activation of IL-10R/STAT3 signaling

Atherosclerosis is a chronic inflammatory disease that may lead to the development of serious cardiovascular diseases. Aged garlic extract (AGE) has been reported to ameliorate atherosclerosis, although its mode of action remains unclear. We found that AGE increased the mRNA or protein levels of arginase1 (Arg1), interleukin-10 (IL-10), CD206 and hypoxia-inducible factor 2α (HIF2α) and decreased that of CD68, HIF1α and inducible nitric oxide synthase in the aorta and spleen of apolipoprotein E knockout mice. We also found that S-1-propenylcysteine (S1PC), a characteristic sulfur compound in AGE, increased the level of IL-10-induced Arg1 mRNA and the extent of M2c-like macrophage polarization in vitro. In addition, S1PC increased the population of M2c-like macrophages, resulting in suppressed the population of M1-like macrophages and decreased lipopolysaccharide-induced production of pro-inflammatory cytokines. These effects were accompanied by prolonged phosphorylation of the IL-10 receptor α (IL-10Rα) and signal transducer and activator of transcription 3 (STAT3) that inhibited the interaction between IL-10Rα and Src homology-2-containing inositol 5’-phosphatase 1 (SHIP1). In addition, administration of S1PC elevated the M2c/M1 macrophage ratio in senescence-accelerated mice. These findings suggest that S1PC may help improve atherosclerosis due to its anti-inflammatory effect to promote IL-10-induced M2c macrophage polarization.

Extraction of apex beat waveform from acoustic pulse wave by sound sensing system using stochastic resonance

With a sound sensing system using stochastic resonance (4SR), it became possible to obtain an acoustic pulse wave (APW)-a waveform created via a mixture of apex beat and heart sound. We examined 50 subjects who were healthy, with no underlying cardiovascular diseases. We could determine boundary frequency (BF) using APW and phonocardiogram signals. APW data was divided into two bands, one from 0.5 Hz to BF, and a second one from BF to 50 Hz. This permitted the extraction of cardiac apex beat (CAB) and cardiac acoustic sound (CAS), respectively. BF could be expressed by a quadratic function of heart rate, and made it possible to collect CAB and CAS in real time. According to heart rate variability analysis, the fluctuation was 1/f, which indicated an efficient cardiac movement when heart rate was 70 to 80/min. In the frequency band between 0.5 Hz and BF, CAB readings collected from the precordial region resembled apex cardiogram data. The waveforms were classified into five types. Therefore, the new 4SR sensing system can be used as a physical diagnostic tool to obtain biological pulse wave data non-invasively and repeatedly over a long period, and it shows promise for broader applications, including AI analysis.

Peripheral arterial stiffness during electrocutaneous stimulation is positively correlated with pain-related brain activity and subjective pain intensity: an fMRI study

Brain activity associated with pain perception has been revealed by numerous PET and fMRI studies over the past few decades. These findings helped to establish the concept of the pain matrix, which is the distributed brain networks that demonstrate pain-specific cortical activities. We previously found that peripheral arterial stiffness [Formula: see text] responds to pain intensity, which is estimated from electrocardiography, continuous sphygmomanometer, and photo-plethysmography. However, it remains unclear whether and to what extent [Formula: see text] aligns with pain matrix brain activity. In this fMRI study, 22 participants received different intensities of pain stimuli. We identified brain regions in which the blood oxygen level-dependent signal covaried with [Formula: see text] using parametric modulation analysis. Among the identified brain regions, the lateral and medial prefrontal cortex and ventral and dorsal anterior cingulate cortex were consistent with the pain matrix. We found moderate correlations between the average activities in these regions and [Formula: see text] (r = 0.47, p < 0.001). [Formula: see text] was also significantly correlated with self-reported pain intensity (r = 0.44, p < 0.001) and applied pain intensity (r = 0.43, p < 0.001). Our results indicate that [Formula: see text] is positively correlated with pain-related brain activity and subjective pain intensity. This study may thus represent a basis for adopting peripheral arterial stiffness as an objective pain evaluation metric.

Recurrent probabilistic neural network-based short-term prediction for acute hypotension and ventricular fibrillation

In this paper, we propose a novel method for predicting acute clinical deterioration triggered by hypotension, ventricular fibrillation, and an undiagnosed multiple disease condition using biological signals, such as heart rate, RR interval, and blood pressure. Efforts trying to predict such acute clinical deterioration events have received much attention from researchers lately, but most of them are targeted to a single symptom. The distinctive feature of the proposed method is that the occurrence of the event is manifested as a probability by applying a recurrent probabilistic neural network, which is embedded with a hidden Markov model and a Gaussian mixture model. Additionally, its machine learning scheme allows it to learn from the sample data and apply it to a wide range of symptoms. The performance of the proposed method was tested using a dataset provided by Physionet and the University of Tokyo Hospital. The results show that the proposed method has a prediction accuracy of 92.5% for patients with acute hypotension and can predict the occurrence of ventricular fibrillation 5 min before it occurs with an accuracy of 82.5%. In addition, a multiple disease condition can be predicted 7 min before they occur, with an accuracy of over 90%.

Disruption of Osteoprotegerin has complex effects on medial destruction and adventitial fibrosis during mouse abdominal aortic aneurysm formation

Aortic aneurysm refers to dilatation of the aorta due to loss of elasticity and degenerative weakening of its wall. A preventive role for osteoprotegerin (Opg) in the development of abdominal aortic aneurysm has been reported in the CaCl₂-induced aneurysm model, whereas Opg was found to promote suprarenal aortic aneurysm in the AngII-induced ApoE knockout mouse aneurysm model. To determine whether there is a common underlying mechanism to explain the impact of Opg deficiency on the vascular structure of the two aneurysm models, we analyzed suprarenal aortic tissue of 6-month-old ApoE^-/-Opg^-/- mice after AngII infusion for 28 days. Less aortic dissection and aortic lumen dilatation, more adventitial thickening, and higher expression of collagen I and Trail were observed in ApoE^-/-Opg^-/- mice relative to ApoE^-/-Opg^+/+ mice. An accumulation of α-smooth muscle actin and vimentin double-positive myofibroblasts was noted in the thickened adventitia of ApoE^-/-Opg^-/- mice. Our results suggest that fibrotic remodeling of the aorta induced by myofibroblast accumulation might be an important pathological event which tends to limit AngII-induced aortic dilatation in ApoE^-/-Opg^-/- mice.

Estimation of Arterial Viscosity Based on an Oscillometric Method and Its Application in Evaluating the Vascular Endothelial Function

This paper proposes an algorithm for estimating the arterial viscosity using cuff pressures and pulse waves measured by an automatic oscillometric sphygmomanometer. A change in the arterial viscosity during the enclosed-zone flow-mediated dilation test is calculated as an index for evaluating the vascular endothelial function %η. In all, 43 individuals participated in this study. After the index %η was calculated, the accuracy of the index %η in distinguishing healthy subjects and subjects at a high risk of arteriosclerosis was tested via a receiving operating characteristic (ROC) analysis. The calculated %η for the healthy participants and those at a high risk of arteriosclerosis was 13.4 ± 55.1% and -32.7 ± 34.0% (mean ± S.D.), respectively. The area under the ROC curve was 0.77. Thus, it was concluded that the proposed method can be used to evaluate the vascular endothelial function.

Unconstrained Monitoring of Biological Signals Using an Aortic Pulse Wave Sensor

This paper proposes a system to extract biological signals from aortic pulse waves which are measured by a microphone type pulse wave sensor. Theproposed system enables extraction of three biological signals corresponding to respiratory rate, pulse pressure wave, and RR interval simply by sitting on the seat on which the sensor is laid. Experiment results demonstrated that the mean absolute errors between the signals measured by the proposed system and the conventional sensors are as low as 0.38 times per minute for the respiratory rate, 11.2 mmHg for the pulse pressure wave, and 16.6 ms for the RR interval. The proposed system thus may be applied to monitor the physiological state of a human subject to prevent accident caused by health condition.

Assessment of Lower-limb Vascular Endothelial Function Based on Enclosed Zone Flow-mediated Dilation

This paper proposes a novel non-invasive method for assessing the vascular endothelial function of lower-limb arteries based on the dilation rate of air-cuff plethysmograms measured using the oscillometric approach. The principle of evaluating vascular endothelial function involves flow-mediated dilation. In the study conducted, blood flow in the dorsal pedis artery was first monitored while lower-limb cuff pressure was applied using the proposed system. The results showed blood flow was interrupted when the level of pressure was at least 50 mmHg higher than the subject’s lower-limb systolic arterial pressure and that blood flow velocity increased after cuff release. Next, values of the proposed index, %ezFMD_L, for assessing the vascular endothelial function of lower-limb arteries were determined from 327 adult subjects: 87 healthy subjects, 150 subjects at high risk of arteriosclerosis and 90 patients with cardiovascular disease (CAD). The mean values and standard deviations calculated using %ezFMD_L were 30.5 ± 12.0% for the healthy subjects, 23.6 ± 12.7% for subjects at high risk of arteriosclerosis and 14.5 ± 15.4% for patients with CAD. The %ezFMD_L values for the subjects at high risk of arteriosclerosis and the patients with CAD were significantly lower than those for the healthy subjects (p < 0.01). The proposed method may have potential for clinical application.

Protective Effects of Japanese Soybean Paste (Miso) on Stroke in Stroke-Prone Spontaneously Hypertensive Rats (SHRSP)

BACKGROUND AND HYPOSESIS

Soybean isoflavones have been shown to reduce the risk of cerebral infarction in humans according to epidemiological studies. However, whether intake of miso can reduce the incidence of stroke in animal models remains unknown. In this study, we investigated the effects of soybean paste (miso) in an animal model of stroke.

METHODS

Stroke-prone spontaneously hypertensive rats (SHRSP) were fed a miso diet (normal diet 90%, miso 10%; final NaCl content 2.8%), a high salt diet (normal diet and NaCl 2.5%; final NaCl content 2.8%), or a low salt diet (normal diet; final NaCl content 0.3%).

RESULTS

Kaplan-Meier survival curves revealed a significantly lower survival rate in the high salt group compared to the miso group (P = 0.002) and the low salt group (P ≤ 0.001). Large hemorrhagic macules were found in the cerebrum in the high salt group, whereas none were found in the other 2 groups. There were also fewer histological and immunohistochemical changes in the brain and kidneys in the miso group compared to the high salt group.

CONCLUSION

Our results suggest that miso may have protective effects against stroke despite its high salt content.

Fish oil omega-3 polyunsaturated fatty acids attenuate oxidative stress-induced DNA damage in vascular endothelial cells

Objective

Omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), likely prevent cardiovascular disease, however their mechanisms remain unclear. Recently, the role of DNA damage in atherogenesis has been receiving considerable attention. Here, we investigated the effects of EPA and DHA on DNA damage in vascular endothelial cells to clarify their antiatherogenic mechanisms.

Methods and results

We determined the effect of EPA and DHA on H₂O₂-induced DNA damage response in human aortic endothelial cells. Immunofluorescence staining showed that γ-H2AX foci formation, a prominent marker of DNA damage, was significantly reduced in the cells treated with EPA and DHA (by 47% and 48%, respectively). H₂O₂-induced activation of ATM, a major kinase orchestrating DNA damage response, was significantly reduced with EPA and DHA treatment (by 31% and 33%, respectively). These results indicated EPA and DHA attenuated DNA damage independently of the DNA damage response. Thus the effects of EPA and DHA on a source of DNA damage were examined. EPA and DHA significantly reduced intracellular reactive oxygen species under both basal condition and H₂O₂ stimulation. In addition, the mRNA levels of antioxidant molecules, such as heme oxygenase-1, thioredoxin reductase 1, ferritin light chain, ferritin heavy chain and manganese superoxide dismutase, were significantly increased with EPA and DHA. Silencing nuclear factor erythroid 2-related factor 2 (NRF2) remarkably abrogated the increases in mRNA levels of antioxidant molecules and the decrease in intracellular reactive oxygen species. Furthermore, EPA and DHA significantly reduced H₂O₂-induced senescence-associated β-galactosidase activity in the cells (by 31% and 22%, respectively), which was revoked by NRF2 silencing.

Conclusions

Our results suggested that EPA and DHA attenuate oxidative stress-induced DNA damage in vascular endothelial cells through upregulation of NRF2-mediated antioxidant response. Therefore omega-3 fatty acids likely help prevent cardiovascular disease, at least in part, by their genome protective properties.

The SGLT2 Inhibitor Luseogliflozin Rapidly Normalizes Aortic mRNA Levels of Inflammation-Related but Not Lipid-Metabolism-Related Genes and Suppresses Atherosclerosis in Diabetic ApoE KO Mice

Recent clinical studies have revealed the treatment of diabetic patients with sodium glucose co-transporter2 (SGLT2) inhibitors to reduce the incidence of cardiovascular events. Using nicotinamide and streptozotocin (NA/STZ) -treated ApoE KO mice, we investigated the effects of short-term (seven days) treatment with the SGLT2 inhibitor luseogliflozin on mRNA levels related to atherosclerosis in the aorta, as well as examining the long-term (six months) effects on atherosclerosis development. Eight-week-old ApoE KO mice were treated with NA/STZ to induce diabetes mellitus, and then divided into two groups, either untreated, or treated with luseogliflozin. Seven days after the initiation of luseogliflozin administration, atherosclerosis-related mRNA levels in the aorta were compared among four groups; i.e., wild type C57/BL6J, native ApoE KO, and NA/STZ-treated ApoE KO mice, with or without luseogliflozin. Short-term luseogliflozin treatment normalized the expression of inflammation-related genes such as F4/80, TNFα, IL-1β, IL-6, ICAM-1, PECAM-1, MMP2 and MMP9 in the NA/STZ-treated ApoE KO mice, which showed marked elevations as compared with untreated ApoE KO mice. In contrast, lipid metabolism-related genes were generally unaffected by luseogliflozin treatment. Furthermore, after six-month treatment with luseogliflozin, in contrast to the severe and widely distributed atherosclerotic changes in the aortas of NA/STZ-treated ApoE KO mice, luseogliflozin treatment markedly attenuated the progression of atherosclerosis, without affecting serum lipid parameters such as high density lipoprotein, low density lipoprotein and triglyceride levels. Given that luseogliflozin normalized the aortic mRNA levels of inflammation-related, but not lipid-related, genes soon after the initiation of treatment, it is not unreasonable to speculate that the anti-atherosclerotic effect of this SGLT2 inhibitor emerges rapidly, possibly via the prevention of inflammation rather than of hyperlipidemia.

A new arterial mechanical property indicator reflecting differences in invasive stimulus intensity induced by alteration of remifentanil concentration during laryngoscopy

BACKGROUND

Reliable analgesia monitoring is not available for general anaesthesia cases. In 2003, we introduced a method to characterise arterial mechanical properties, which we termed arterial stiffness (K). However, it is unclear whether differences in K actually indicate changes in the intensity of a noxious stimulus. Thus, we examined the relationship between stress intensity and the value of K.

METHODS

Thirty patients under general anesthesia were randomly divided into two remifentanil concentration groups (2 and 6 ng/mL). After a steady concentration of remifentanil was achieved for at least 3 minutes, laryngoscopy was performed. After completion of laryngoscopy, once the K value returned to near-baseline, laryngoscopy with endotracheal intubation was performed, and the value of K after the procedure was recorded and analyzed.

RESULTS

In total, data were obtained for 28 of 30 patients. The values of K before the laryngoscopy were not significantly different between the groups (2 ng/mL group: 13.1 [8.5-33.1] mmHg/%; 6 ng/mL group: 11.6 [4.3-31.4] mmHg/%; P=0.53). After laryngoscopy, K was approximately 2 times greater in the 2 ng/mL group than in the 6 ng/mL group (39.0 [13.6-115.9] mmHg/% vs. 19.0 [5.5-85.1] mmHg/%, P=0.02). After intubation also, K was approximately 2 times greater in the 2 ng/mL group (52.0 [27.7-122.0] mmHg/% vs. 24.3 [7.2-94.9] mmHg/%, P=0.04).

CONCLUSIONS

The value for arterial stiffness (K) non-proportionally changes in response to stimulus intensity; therefore, it has the potential to be used as an indicator of nociceptive stimulation intensity.

EPA Prevents the Development of Abdominal Aortic Aneurysms through Gpr-120/Ffar-4

Abdominal aortic aneurysms (AAAs), which commonly occur among elderly individuals, are accompanied by a risk of rupture with a high mortality rate. Although eicosapentaenoic acid (EPA) has been reported to prevent AAA formation, the mechanism by which EPA works on vascular smooth muscle cells is unknown. This study aimed to investigate the mechanism by which orally-administered EPA prevents the formation of severe AAAs that develop in Osteoprotegerin (Opg) knockout (KO) mice. In the CaCl₂-induced AAA model, EPA attenuated the enhanced progression of AAAs in Opg-KO mice, including the increase in aortic diameter with destruction of elastic fibers in the media. Immunohistochemical analyses showed that EPA reduced the phosphorylation of transforming growth factor beta-activated kinase-1/Map3k7 (Tak-1) and c-Jun NH2-terminal kinase (JNK), as well as the expression of Matrix metalloproteinase-9 (Mmp-9) in the media of the aorta. In smooth muscle cell cultures, rh-TRAIL-induced activation of the Tak-1-JNK pathway and increase in Mmp-9 expression were inhibited by EPA. Moreover, GW9508, a specific ligand for G-protein coupled receptor (Gpr)-120/Free fatty acid receptor (Ffar)-4, mimicked the effects of EPA. The effects of EPA were abrogated by knockdown of the Gpr-120/Ffar-4 receptor gene. Our data demonstrate that the Trail-Tak-1-JNK-Mmp-9 pathway is responsible for the enhancement of AAAs in Opg-KO mice, and that EPA inhibits the Tak-1-JNK pathway by activating Gpr-120/Ffar-4, which results in the attenuation of AAA development.

Quantitative Evaluation of Intraarterial Lymphocyte Injection Therapy for Lymph Edema Using MR Imaging

Five patients with unilateral leg lymph edema had intraarterial injections of lymphocytes in the affected leg with consequent improvement in 3. To assess the degree of lymph edema, T2 and intensity ratio between the 2 legs in STIR images were used. Mean and SD of T2 values in the subcutaneous tissue were measured using a triple echo sequence and found larger on the edematous side than in the opposite extremity. The mean T2 shortening obtained after the lymphocyte therapy correlated well with the reduction of limb circumference. Mean T2 reflects the fluid content, and SD of T2 the fluid distribution in the subcutaneous tissue. The degree of lymph edema and the effect of therapy can be evaluated quantitatively by measuring the value of the T2 relaxation time.

Osteoprotegerin Prevents Development of Abdominal Aortic Aneurysms

Abdominal aortic aneurysms (AAAs), which commonly occur among elderly individuals, are accompanied by a risk of rupture and subsequent high mortality. Establishment of medical therapies for the prevention of AAAs requires further understanding of the molecular pathogenesis of this condition. This report details the possible involvement of Osteoprotegerin (OPG) in the prevention of AAAs through inhibition of Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). In CaCl₂-induced AAA models, both internal and external diameters were significantly increased with destruction of elastic fibers in the media in Opg knockout (KO) mice, as compared to wild-type mice. Moreover, up-regulation of TRAIL expression was observed in the media by immunohistochemical analyses. Using a culture system, both the TRAIL-induced expression of matrix metalloproteinase-9 in smooth muscle cells (SMCs) and the chemoattractive effect of TRAIL on SMCs were inhibited by OPG. These data suggest that Opg may play a preventive role in the development of AAA through its antagonistic effect on Trail.

Monitoring of peripheral vascular condition using a log-linearized arterial viscoelastic index during endoscopic thoracic sympathectomy

This paper proposes a novel technique to support the monitoring of peripheral vascular conditions using biological signals such as electrocardiograms, arterial pressure values and pulse oximetry plethysmographic waveforms. In this approach, a second-order log-linearized model (referred to here as a log-linearized peripheral arterial viscoelastic model) is used to describe the non-linear viscoelastic relationship between blood pressure waveforms and photo-plethysmographic waveforms. The proposed index enables estimation of peripheral arterial wall stiffness changes induced by sympathetic nerve activity. The validity of the method is discussed here based on the results of peripheral vascular condition monitoring conducted during endoscopic thoracic sympathectomy (ETS). The results of ETS monitoring showed significant changes in stiffness variations between the periods before and during the procedures observed (p < 0.01) as well as during and after them (p < 0.01), so that it was confirmed that sympathetic nerve activity is drastically decreased in the area around the monitoring site after the thoracic sympathetic nerve trunk on the monitoring side is successfully blocked. In addition, no change was observed in the values of the proposed index during the ETS procedure on the side opposite that of the monitoring site. The experimental results obtained clearly show the proposed method can be used to assess changes in sympathetic nerve activity during ETS.

Efficacy of HMG-CoA reductase inhibitors in the prevention of cerebrovascular attack in 1016 patients older than 75 years among 4014 type 2 diabetic individuals

BACKGROUND/OBJECTIVES

HMG-CoA reductase inhibitors (statins) reduce ischemic heart disease (IHD) in middle-aged diabetic individuals, and LDL-cholesterol (LDL-C) is a risk factor. However, their preventive effects on cerebrovascular attack (CVA) have not been identified in elderly, especially in elderly ≥ 75 years (late elderly), who account for approximately 30% of diabetic individuals in Japan. Randomized controlled studies of statins for late elderly are difficult to carry out, because many co-morbidities in elderly disrupt randomized controlled conditions.

METHODS

We performed a prospective cohort study (Japan Cholesterol and Diabetes Mellitus Study) with 5.5 years of follow-up since 2004. A total of 4014 type 2 diabetic patients without previous IHD or CVA (n=1936 women; age = 67.4 ± 9.5 years; ≥ 75 years: n = 1016) were enrolled, while 405 patients were registered as sub-cohort patients. We recorded detailed information on medications and laboratory data after every change in medication in patients of sub-cohort and suffered from IHD or CVA. We subdivided statin-users into prevalent, new and non-users.

RESULTS

A total of 104 CVAs occurred during 5.5-years. Plasma HDL-C level was inversely correlated with CVA in patients ≥ 65 years. In case-control study, among patients who were not prescribed statins, CVA increased in age-dependent manner. CVA incidence was lower in prevalent and new statin-users than in non-users (hazard ratio [HR]:0.46, 0.523), especially in late elderly (HR: 0.51, 0.21). Statins reduced CVAs mainly due to a direct effect and partially due to the effects of HDL-C and glucose metabolism. No significant differences were observed between statins.

CONCLUSION

Statins prevented CVA in middle-aged, elderly and late elderly diabetic patients via a direct effect. This study is the first to demonstrate the usefulness of observational studies for statistically analyzing agents' effects on late elderly.

Smoking cessation reverses DNA double-strand breaks in human mononuclear cells

OBJECTIVE

Cigarette smoking is a major risk factor for atherosclerotic cardiovascular disease, which is responsible for a significant proportion of smoking-related deaths. However, the precise mechanism whereby smoking induces this pathology has not been fully delineated. Based on observation of DNA double-strand breaks (DSBs), the most harmful type of DNA damage, in atherosclerotic lesions, we hypothesized that there is a direct association between smoking and DSBs. The goal of this study was to investigate whether smoking induces DSBs and smoking cessation reverses DSBs in vivo through examination of peripheral mononuclear cells (MNCs).

APPROACH AND RESULTS

Immunoreactivity of oxidative modification of DNA and DSBs were increased in human atherosclerotic lesions but not in the adjacent normal area. DSBs in human MNCs isolated from the blood of volunteers can be detected as cytologically visible "foci" using an antibody against the phosphorylated form of the histone H2AX (γ-H2AX). Young healthy active smokers (n = 15) showed increased γ-H2AX foci number when compared with non-smokers (n = 12) (foci number/cell: median, 0.37/cell; interquartile range [IQR], 0.31-0.58 vs. 4.36/cell; IQR, 3.09-7.39, p<0.0001). Smoking cessation for 1 month reduced the γ-H2AX foci number (median, 4.44/cell; IQR, 4.36-5.24 to 0.28/cell; IQR, 0.12-0.53, p<0.05). A positive correlation was noted between γ-H2AX foci number and exhaled carbon monoxide levels (r = 0.75, p<0.01).

CONCLUSIONS

Smoking induces DSBs in human MNCs in vivo, and importantly, smoking cessation for 1 month resulted in a decrease in DSBs to a level comparable to that seen in non-smokers. These data reinforce the notion that the cigarette smoking induces DSBs and highlight the importance of smoking cessation.

Role of DNA damage in cardiovascular disease

Patients with some progeroid syndromes, such as Werner syndrome, exhibit atherosclerotic cardiovascular disease (CVD) at a young age as a manifestation of premature aging. Recent studies have revealed that most progeroid syndromes are caused by genetic defects in specific molecules involved in the DNA damage response, a cornerstone of genome stability. Ionizing radiation is one of the most potent genotoxic stimuli and causes various kinds of DNA damage. Further, there is increasing evidence that therapeutic radiation treatments can cause cardiovascular complications. Here, we describe the DNA damage and subsequent response, review recent advances in the understanding of the molecular basis of progeroid syndromes (especially those syndromes that involve CVD), review the pathological and epidemiological analysis of radiation-induced CVD, and discuss the possible role of DNA damage and the DNA damage response in the pathogenesis of atherosclerotic CVD.

Induction of Timp1 in smooth muscle cells during development of abdominal aortic aneurysms

Abdominal aortic aneurysm (AAA) is known to develop mainly by the increased diameter of aorta through metalloproteinases (MMPs). Although activities of MMPs are tightly regulated by the presence of tissue inhibitor of MMPs (TIMPs) and imbalances between MMPs and TIMPs may serve to fragility of arterial wall, little is known about TIMPs behavior in aneurysmal formation. Here, we utilized a murine experimental AAA model, and found that by immunohistochemical analysis, Timp1 as and Timp1 mRNA levels was also revealed in aortic tissue in AAA by RT-PCR. In cultured vascular smooth muscle cells (SMCs), Tumor Necrosis Factor (TNF)-alpha significantly activated both Mmp9 and Timp1 expression, and they were blocked by Jun kinase inhibitor (SP600125) in a dose-dependent manner. Interestingly, a proteasome inhibitor (MG132), which is known as an agent for inhibition of the nuclear factor-kappa B (NF-kappaB), significantly inhibited the TNF-alpha-induced expression of Timp1, whereas MG132, which also works as an activator of c-Jun/AP-1 pathway, strongly increased Mmp9. Taken together, inflammatory cytokines, including TNF-alpha, may simultaneously induce MMPs and TIMPs for the remodeling of the medial layer, leading to the increased diameter of the aorta, the aneurysm.

Cross-talk of receptor activator of nuclear factor-κB ligand signaling with renin-angiotensin system in vascular calcification

OBJECTIVE

Vascular calcification is accelerated by hypertension and also contributes to hypertension; however, it is an enigma why hypertension and vascular calcification are a vicious spiral. The present study elucidates the cross-talk between renin-angiotensin II system and receptor activator of nuclear factor-κB ligand (RANKL) system in vascular calcification.

APPROACH AND RESULTS

Angiotensin (Ang) II (10(-7) mol/L) significantly increased calcium deposition as assessed by Alizarin Red staining, associated with a significant increase in the expression of RANKL, RANK, and bone-related genes, such as cbfa1 and msx2, in human aortic vascular smooth muscle cells. Infusion of Ang II (100 ng/kg per minute) in ovariectomized ApoE(-/-) mice under high-fat diet significantly increased the expression of RANKL system and calcification in vivo, whereas administration of Ang II receptor blocker (olmesartan, 3 mg/kg per day) decreased the calcification and bone markers' expression. In addition, male OPG(-/-) mice showed a significant increase in vascular calcification followed by Ang II infusion as compared with wild type. Conversely, RANKL significantly increased Ang II type 1 receptor and angiotensin II-converting enzyme expression in vascular smooth muscle cells via extracellular signal-regulated protein kinase phosphorylation.

CONCLUSIONS

The present study demonstrated that Ang II significantly induced vascular calcification in vitro and in vivo through RANKL activation. In addition, RANKL activated renin-angiotensin II system, especially angiotensin II-converting enzyme and Ang II type 1 receptor. Cross-talk between renin-angiotensin II system and RANKL system might work as a vicious cycle to promote vascular calcification in atherosclerosis. Further studies to inhibit renin-angiotensin II system and RANKL may provide new therapeutic options to prevent and regress vascular calcification.

Hesr2 knockout mice develop aortic valve disease with advancing age

OBJECTIVE

Acquired heart diseases, such as valve disease, are major causes of human morbidity and mortality. However, the pathological mechanisms underlying these diseases are largely unknown. Our aim is to identify the role of the hairy and enhancer of split-related (Hesr)-2 gene in the adult heart.

METHODS AND RESULTS

Echocardiography detected heart dysfunctions indicative of aortic valve anomalies, stenosis, and regurgitation, in ≈59% of >12-month-old Hesr2 knockout survivor mice. Morphological and histological analyses revealed thickened semilunar valves with increased fibrotic areas, indicating that sclerotic degeneration of valves is the main cause of aortic valve disease. The expression of osteogenic genes, such as osteopontin and sclerostin, were upregulated in the mutants, and the overexpression of sclerostin in endothelial cells resulted in thickened semilunar valves with increased fibrotic areas, similar to that seen in the Hesr2 knockout mice, suggesting that Hesr2 can regulate osteogenic gene expression in valves. Reduced left ventricular function, which may be caused by increased ventricular interstitial fibrosis, and enlarged myocardial cell size without ventricular wall thickening were found in both aortic valve stenosis/regurgitation-positive (33%) and aortic valve stenosis/regurgitation-negative (38%) subpopulations in 12-month-old survivor mice. Dilated left ventricular internal dimensions were specifically detected in the aortic valve stenosis/regurgitation-positive subpopulation, thus suggesting that the degeneration of cardiomyocytes is influenced by irregular hemodynamics.

CONCLUSIONS

These data revealed that survivor mice lacking the Hesr2 gene exhibit fibrosis in the aortic valve and ventricle in adulthood, thus suggesting that Hesr2 plays an important role in maintaining the homeostasis of the aortic valve and ventricle.

A log-linearized arterial viscoelastic model for evaluation of the carotid artery

This paper proposes a method for qualitatively estimating the mechanical properties of arterial walls on a beat-to-beat basis through noninvasive measurement of continuous arterial pressure and arterial diameter using an ultrasonic device. First, in order to describe the nonlinear relationships linking arterial pressure waveforms and arterial diameter waveforms as well as the viscoelastic characteristics of arteries, we developed a second-order nonlinear model (called the log-linearized arterial viscoelastic model) to allow estimation of arterial wall viscoelasticity. Next, to verify the validity of the proposed method, the viscoelastic indices of the carotid artery were estimated. The results showed that the proposed model can be used to accurately approximate the mechanical properties of arterial walls. It was therefore deemed suitable for qualitative evaluation of arterial viscoelastic properties based on noninvasive measurement of arterial pressure and arterial diameter.

Novel non-invasive method of measurement of endothelial function: enclosed-zone flow-mediated dilatation (ezFMD)

Measurement of flow-mediated dilatation (FMD) is the conventional non-invasive method for assessment of endothelial function; however, it requires an expensive ultrasound system and high levels of technical skill. Therefore, we developed a novel method for measurement of endothelial function, namely, measurement of ezFMD. ezFMD estimates the degree of vasodilatation from the oscillation signals transmitted to a sphygmomanometer cuff attached to the upper arm. The objective of this study was to validate the principle underlying the measurement of ezFMD, and to evaluate the repeatability of the ezFMD measurements. We observed the blood vessel behavior and oscillometric pattern in ten subjects. When the cuff was inflated to the level of the mean blood pressure, the oscillation amplitude increased with increasing degree of vasodilatation. In experiment to evaluate the repeatability of the ezFMD measurement, the average difference between the paired measurements was 3.7 %, the standard deviation was 11.5 %, and the average coefficient of variation value for the 11 paired measurements was 23.7 %. These results suggest the validity of the principle underlying the measurement of the ezFMD for the assessment of endothelial function. And, this study suggests that the repeatability of the ezFMD measurements is superior to that of the conventional measurement of FMD.

Abstract P321: Oxidative Stress Induces DNA Double-Strand Breaks and Activates DNA Damage Responses in Vascular Smooth Muscle Cells: A Possible Mechanism for Atherosclerosis Progression

Backgrounds: Oxidative stress is thought to be a pathogenic mediator of atherosclerosis. Oxidative stress induces DNA damage, and the unrepaired or improperly repaired DNA damage increases genomic instability, which cause cell death, senescence, or dysregulation of cellular functions. Pathogenesis of both Hutchinson-Gilford Progeria syndrome and Werner syndrome, which feature prominent atherosclerotic disease at young age, involves impaired DNA repair and the resultant genomic instability. The purpose of this study is to determine whether oxidative stress causes DNA damage in vascular smooth muscle cells (VSMC) and to elucidate the role of DNA damage responses in atherosclerosis and the fate of VSMC.

Methods and Results: Immunoreactivity against gamma-H2AX, a sensitive marker for DNA double-strand breaks (DSBs), which is the most severe form of DNA damage, was increased in human atherosclerotic plaques, but not in the adjacent normal areas. gamma-H2AX staining was observed in almost same regions where 8-oxo-dG immunoreactivity, an oxidative modification of DNA, was observed. Apoptotic cells were abundant in atherosclerotic lesions, but not in normal areas. In cultured human aortic smooth muscle cells (HASM), 15 min incubation with H2O2 (100 microM) induced foci formation of gamma-H2AX in the nuclei. H2O2 activated various signaling molecules involved in DNA damage responses, including ATM, Chk2, DNA-PK and p53 in HASM. Some H2O2-induced DSBs persisted after 24 hours, at which point apoptosis was induced in 7.1 ± 1.3 % of HASM, as detected by TUNEL method. Knockdown experiments using siRNA revealed that ATM-, DNA-PK-, or Chk2-deficient VSMC were more resistant to H2O2-induced apoptosis.

Conclusions: In summary, 1) DNA double-strand breaks were accumulated in human atherosclerotic plaques, 2) oxidative stress induced double-strand breaks and activation of DNA damage response in vascular smooth muscle cells, and 3) impairment of DNA damage responses modulated damage-induced cell fate such as apoptosis. Thus, DNA damage itself or alteration in DNA damage responses may be involved in the mechanisms for progression of atherosclerosis.

Age, gender, insulin and blood glucose control status alter the risk of ischemic heart disease and stroke among elderly diabetic patients

Background

We analyzed the effects of insulin therapy, age and gender on the risk of ischemic heart disease (IHD) and cerebrovascular accident (CVA) according to glycemic control.

Methods and Results

We performed a prospective cohort study (Japan Cholesterol and Diabetes Mellitus Study) of type 2 diabetes patients (n = 4014) for 2 years. The primary endpoint was the onset of fatal/non-fatal IHD and/or CVA, which occurred at rates of 7.9 and 7.2 per 1000 person-years, respectively. We divided diabetic patients into four groups based on age (≤ 70 and > 70) and hemoglobin A1C levels (≤ 7.0 and > 7.0%). Multiple regression analysis revealed that IHD was associated with high systolic blood pressure and low HDL-C in patients under 70 years of age with fair glycemic control and was associated with low diastolic blood pressure in the older/fair group. Interestingly, insulin use was associated with IHD in the older/poor group (OR = 2.27, 95% CI = 1.11-5.89; p = 0.026) and was associated with CVA in the older/fair group (OR = 2.09, 95% CI = 1.06-4.25; p = 0.028). CVA was associated with lower HDL-C and longer duration of diabetes in younger/poor glycemic control group. Results by stepwise analysis were similar. Next, patients were divided into four groups based on gender and diabetic control(hemoglobinA1C < or > 7.0%). Multiple regression analysis revealed that IHD was associated with high systolic blood pressure in male/fair glycemic control group, age in male/poor control group, and short duration of diabetic history in females in both glycemic control groups. Interestingly, insulin use was associated with IHD in the male/poor group(OR = 4.11, 95% CI = 1.22-8.12; p = 0.018) and with CVA in the female/poor group(OR = 3.26, 95% CI = 1.12-6.24; p = 0.02). CVA was associated with short duration of diabetes in both female groups.

Conclusions

IHD and CVA risks are affected by specific factors in diabetics, such as treatment, gender and age. Specifically, insulin use has a potential role in preventing IHD but may also be a risk factor for CVA among the diabetic elderly, thus revealing a need to develop improved treatment strategies for diabetes in elderly patients. The Japan Cholesterol and Diabetes Mellitus Study was formulated to evaluate them(Umin Clinical Trials Registry, clinical trial reg. no. UMIN00000516; http://www.umin.ac.jp/ctr/index.htm).

Transthoracic tissue Doppler assessment of left atrial appendage contraction and relaxation: their changes with aging

AIM

We assessed left atrial appendage (LAA) function using transthoracic tissue Doppler echocardiography (TDE), and examined the influence of aging on LAA contraction and relaxation.

METHODS

The subjects were 45 consecutive patients with heart disease and 110 healthy individuals. LAA wall motion velocity (LAAWV) at the tip of the LAA was measured using transthoracic echocardiography (TTE) and/or transesophageal echocardiography (TEE).

RESULTS

We successfully recorded and measured LAAWV using TTE in 105 (95%) of the 110 healthy subjects. When angle correction was applied for the Doppler beam in TTE, LAAWV during contraction (LAAWVc) measured by TTE closely correlated with that measured by TEE (r = 0.97), and LAAWV during relaxation (LAAWVr) measured by TTE closely correlated with that measured by TEE (r = 0.95). LAAWVc and LAAWVr measured by TTE correlated significantly with the LAA flow velocities during LAA contraction and LAA relaxation measured by TEE (r = 0.64, P < 0.001; r = 0.53, P = 0.001). In healthy subjects, although LAAWVc remained unchanged with aging, LAAWVr significantly declined with aging (r =-0.48, P < 0.001) and had a significant negative correlation with left atrial dimension and a significant positive correlation with transmitral flow and annulus velocity during early diastole.

CONCLUSION

Transthoracic TDE can provide information on LAA function. LAA relaxation may be impaired with aging and may be accompanied by early diastolic left ventricular dysfunction and chronic overload to the left atrium.

Noninvasive biological sensor system for detection of drunk driving

Systems capable of monitoring the biological condition of a driver and issuing warnings during instances of drowsiness have recently been studied. Moreover, many researchers have reported that biological signals, such as brain waves, pulsation waves, and heart rate, are different between people who have and have not consumed alcohol. Currently, we are developing a noninvasive system to detect individuals driving under the influence of alcohol by measuring biological signals. We used the frequency time series analysis to attempt to distinguish between normal and intoxicated states of a person as the basis of the sensing system.

A novel online method to monitor autonomic nervous activity based on arterial wall impedance and heart rate variability

This paper proposes a new method of evaluating autonomic nervous activity using the mechanical impedance of arterial walls and heart rate variability. The cardiovascular system is indispensable to life maintenance functions, and homeostasis is maintained by the autonomic nervous system. Accordingly, it is very important to be able to make diagnosis based on autonomic nervous activity within the body's circulation. The proposed method was evaluated in surgical operations; the mechanical impedance of the arterial wall was estimated from arterial blood pressure and a photoplethysmogram, and heart rate variability was estimated using electrocardiogram R-R interval spectral analysis. In this paper, we monitored autonomic nervous system activity using the proposed system during endoscopic transthoracic sympathetic block surgery in eight patients with hyperhidrosis. The experimental results indicated that the proposed system can be used to estimate autonomic nervous activity in response to events during operations.

Endothelial function and oxidative stress in cardiovascular diseases

The vascular endothelium is involved in the release of various vasodilators, including nitric oxide (NO), prostacyclin and endothelium-derived hyperpolarizing factor, as well as vasoconstrictors. NO plays an important role in the regulation of vascular tone, inhibition of platelet aggregation, and suppression of smooth muscle cell proliferation. Endothelial dysfunction is the initial step in the pathogenesis of atherosclerosis. Cardiovascular diseases are associated with endothelial dysfunction. It is well known that the grade of endothelial function is a predictor of cardiovascular outcomes. Oxidative stress plays an important role in the pathogenesis and development of cardiovascular diseases. Several mechanisms contribute to impairment of endothelial function. An imbalance of reduced production of NO or increased production of reactive oxygen species, mainly superoxide, may promote endothelial dysfunction. One mechanism by which endothelium-dependent vasodilation is impaired is an increase in oxidative stress that inactivates NO. This review focuses on recent findings and interaction between endothelial function and oxidative stress in cardiovascular diseases.

Determinants of enhanced left atrial active emptying with aging: left atrial preload, contractility or both?

OBJECTIVE

Senile persons have reduced left ventricular (LV) relaxation and increased late diastolic filling. However, the determinant factor of the enhanced active emptying of the left atrium has not been well established.

METHODS

Subjects were 62 healthy individuals with a mean age of 58+/-19 (21-85) years. The biplane modified Simpson's rule was applied to measure left atrial (LA) volume at pre-atrial contraction (LAVpre) as an index of LA preload and LA volume change during atrial contraction (LASV) as an index of active LA emptying. These values were divided by the body surface area and represented as LAVpreI and LASVI, respectively. Postero-basal (dorsal cranial) left atrial wall velocity (LAWV) during atrial contraction as an index of LA contractility was measured in the apical three-chamber view by two-dimensional tissue Doppler echocardiography.

RESULTS

Age significantly correlated with mitral flow velocity (TMA), velocity-time integral during atrial contraction (TMAVTI) and LASVI (r= 0.63, p<0.001 and r=0.71, p<0.001, r=0.21, p=0.049, respectively). LAVpreI was significantly correlated with age (r=0.44, p<0.001), LASVI (r=0.71, p<0.001), TMA (r=0.31, p=0.008) and TMAVTI (r=0.40, p<0.001). LAWV remained unchanged with aging and had no correlation with TMA, TMAVTI or LASVI.

CONCLUSION

The enlargement of the LA in senile persons may be a major determinant of enhanced active LA emptying and the increased LA contractility may be less contributory.

Coronary vasospasm produces reversible perfusion defects observed during adenosine triphosphate stress myocardial single-photon emission computed tomography

BACKGROUND

Adenosine triphosphate stress thallium-201 single-photon emission computed tomography (ATP-SPECT) is useful for diagnosing coronary artery disease (CAD), although sometimes false positive results are observed. It has not been established whether a coronary spasm is responsible for the false positive findings during ATP-SPECT.

HYPOTHESIS

We investigated whether coronary spasm is one of the factors which produces reversible defects on ATP-SPECT.

METHODS

Eighty-six patients (mean age: 62 y; 58 men) who underwent both spasm-provocation testing by coronary angiography and ATP-SPECT, were selected for the study. Patients with coronary narrowing (>30%), myocardial infarction, or heart failure were excluded. Patients were divided into 2 groups based on whether the spasm-provocation test result was positive (vasospastic angina [VSA] group, n = 46) or negative (non-VSA group, n = 39).

RESULTS

The body mass index was lower in the VSA group than in the non-VSA group (p = 0.005). On ATP-SPECT imaging, any type of reversible defect was observed more frequently in the VSA group (68%) than in the non-VSA group (36%, p = 0.0027). Logistic regression analysis demonstrated that the presence of reversible defects was one of the factors accounting for the presence of coronary vasospasm (p = 0.0022, R2 = 0.172).

CONCLUSIONS

The findings suggest that reversible defects on ATP-SPECT imaging are frequently present in patients with coronary vasospasm. Coronary spasm may be considered as 1 of the factors, which produce reversible defects on ATP-SPECT, observed in patients with chest symptoms and angiographically normal coronary arteries.

Relationship between augmentation index and flow-mediated vasodilation in the brachial artery

Recent studies have shown that the augmentation index (AI) is a predictor of cardiovascular complications. Endothelial dysfunction is the initial step in the pathogenesis of atherosclerosis, which in turn can lead to cardiovascular complications. Endothelial function assessed by flow-mediated dilation (FMD) can serve as an independent predictor of cardiovascular events. However, there is little information on the relationship between AI and FMD in the human vasculature, and we therefore investigated this relationship in the present study. A total of 100 subjects (71 males and 29 females; age range, 22-88 years; mean age, 59 +/- 17 years), including 83 patients with cardiovascular diseases (e.g., atherosclerosis, hypertension, coronary heart disease, stroke and peripheral arterial disease) and 17 healthy subjects were enrolled. High-resolution ultrasonography (automated vessel-diameter measurements; eTRACKING system), a linear array transducer (13 MHz) and an arm holding device were used to measure the arterial diameter response to reactive hyperemia and sublingual nitroglycerine (NTG, 75 micrograms) in all subjects. AI measured using an automated device was significantly correlated with FMD (r = -0.38, p < 0.0001). There was no significant correlation between AI and vascular response to NTG. Multiple regression analysis showed that FMD was a significant independent predictor of AI (p < 0.05). These findings suggest that increase in arterial stiffness may be associated with grade of endothelial dysfunction and that AI may be an index of not only arterial stiffness but also endothelial function.

Myocardial Protection Against Pressure Overload in Mice Lacking Bach1, a Transcriptional Repressor of Heme Oxygenase-1

Bach1 is a stress-responsive transcriptional factor that is thought to control the expression levels of cytoprotective factors, including heme-oxygenase (HO)-1. In the present study, we investigated the roles of Bach1 in the development of left ventricular (LV) hypertrophy and remodeling induced by transverse aortic constriction (TAC) in vivo using Bach1 gene-deficient ( Bach1 −/− ) mice. TAC for 3 weeks in wild-type control ( Bach1 +/+ ) mice produced LV hypertrophy and remodeling manifested by increased heart weight, histological findings showing increased myocyte cross-sectional area (CSA) and interstitial fibrosis (picro Sirius red staining), reexpressions of ANP, BNP, and βMHC genes, and echocardiographic findings showing wall thickening, LV dilatation, and reduced LV contraction. Deletion of Bach1 caused significant reductions in heart weight (by 16%), CSA (by 36%), tissue collagen content (by 38%), and gene expression levels of ANP (by 75%), BNP (by 45%), and βMHC (by 74%). Echocardiography revealed reduced LV dimension and ameliorated LV contractile function. Deletion of Bach1 in the LV caused marked upregulation of HO-1 protein accompanied by elevated HO activity in both basal or TAC-stimulated conditions. Treatment of Bach1 −/− mice with tin-protoporphyrin, an inhibitor of HO, abolished the antihypertrophic and antiremodeling effects of Bach1 gene ablation. These results suggest that deletion of Bach1 caused upregulation of cytoprotective HO-1, thereby inhibiting TAC-induced LV hypertrophy and remodeling, at least in part, through activation of HO. Bach1 repressively controls myocardial HO-1 expression both in basal and stressed conditions, inhibition of Bach1 may be a novel therapeutic strategy to protect the myocardium from pressure overload.

Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one), a novel free radical scavenger, for treatment of cardiovascular diseases

Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one), a strong novel free radical scavenger, is used for treatment of patients with acute brain infarction. Edaravone has preventive effects on myocardial injury following ischemia and reperfusion in patients with acute myocardial infarction. Antioxidant actions of edaravone include enhancement of prostacyclin production, inhibition of lipoxygenase metabolism of arachidonic acid by trapping hydroxyl radicals, inhibition of alloxan-induced lipid peroxidation, and quenching of active oxygen, leading to protection of various cells, such as endothelial cells, against damage by reactive oxygen species (ROS). Recently, we have shown that edaravone improves endothelial function through a decrease in ROS in smokers. From a clinical perspective, it is important to select an appropriate drug that is effective in improving endothelial function in patients with cardiovascular diseases. The novel free radical scavenger edaravone may represent a new therapeutic intervention for endothelial dysfunction in the setting of atherosclerosis, chronic heart failure, diabetes mellitus, or hypertension. This review focuses on clinical findings and on putative mechanisms underlying the beneficial effects of the antioxidative agent edaravone on the artherosclerotic process in patients with cardiovascular diseases.

Pycnogenol, French maritime pine bark extract, augments endothelium-dependent vasodilation in humans

Pycnogenol, an extract of bark from the French maritime pine, Pinus pinaster Ait., consists of a concentrate of water-soluble polyphenols. Pycnogenol contains the bioflavonoids catechin and taxifolin as well as phenolcarbonic acids. Antioxidants, such as bioflavonoids, enhance endothelial nitric oxide (NO) synthase expression and subsequent NO release from endothelial cells. The purpose of this study was to determine Pycnogenol's effects on endothelium-dependent vasodilation in humans. This was a double-blind, randomized, placebo and active drug study. We evaluated forearm blood flow (FBF) responses to acetylcholine (ACh), an endothelium-dependent vasodilator, and to sodium nitroprusside (SNP), an endothelium-independent vasodilator, in healthy young men before and after 2 weeks of daily oral administration of Pycnogenol (180 mg/day) (n=8) or placebo (n=8). FBF was measured by using strain-gauge plethysmography. Neither the placebo nor Pycnogenol altered forearm or systemic hemodynamics. Pycnogenol, but not placebo, augmented FBF response to ACh, from 13.1 +/- 7.0 to 18.5 +/- 4.0 mL/min per 100 mL tissue (p<0.05). SNP-stimulated vasodilation was similar before and after 2 weeks of treatment in the control and Pycnogenol groups. The administration of N(G)-monomethyl-L-arginine, an NO synthase inhibitor, completely abolished Pycnogenol-induced augmentation of the FBF response to ACh. These findings suggest that Pycnogenol augments endothelium-dependent vasodilation by increasing in NO production. Pycnogenol would be useful for treating various diseases whose pathogeneses involve endothelial dysfunction.