Ken Kitajima

Apolipoprotein A-I Deficiency Results in Markedly Increased Atherosclerosis in Mice Lacking the LDL Receptor

Objective—An inverse and independent association between plasma levels of apolipoprotein (apo) A-I and coronary heart disease in humans is well established. ApoA-I is the primary protein component of HDL and is thought to play an important role in mediating several of the atheroprotective effects of HDL. However, studies of the effects of apoA-I deficiency on the development of atherosclerosis in mice have not been definitive. We examined the effects of apoA-I deficiency on plasma lipids and atherosclerosis in LDL receptor-deficient mice fed a chow diet for up to 22 months. Methods and Results—Both apoA-I-deficient (apoA-I−/−)/LDL receptor-deficient (LDLR−/−) and LDLR−/− mice had a similar moderate elevation of non-HDL cholesterol (non-HDL-C). Unlike previous studies of apoA-I deficiency in which the HDL-C levels were extremely low, the apoA-I−/−/LDLR−/− mice in this study had substantial levels of HDL-C that were similar to wild-type mice. Despite similar levels of non-HDL-C and substantial levels of HDL-C, apoA-I−/−/LDLR−/− mice develop significantly more atherosclerosis (up to a 5-fold increase) and oxidant stress (39% increase) than LDLR−/− mice. Conclusions—These results demonstrate that despite normal levels of HDL-C, apoA-I deficiency is associated with a significant loss of protection from the formation of atherosclerosis in LDLR−/− mice fed a chow diet.

Complete Prevention of Atherosclerosis in ApoE-Deficient Mice by Hepatic Human ApoE Gene Transfer With Adeno-Associated Virus Serotypes 7 and 8

Objective—Using intravenous injection of adeno-associated viral (AAV) vectors based on novel serotypes 7 and 8, we examined whether liver-specific expression of human apolipoprotein E (apoE) in apoE-deficient mice would completely prevent atherosclerosis after 1 year of sustained expression. Methods and Results—Chow-fed apoE−/− mice were injected via the tail vein with vectors based on AAV2 or novel serotypes AAV7 and AAV8 encoding human apoE3 driven by a liver-specific promoter. In contrast to the first-generation AAV2 vector, apoE levels of mice injected with chimeric AAV2/7 and AAV2/8 vectors reached ≈2-fold greater than normal human plasma levels by week 4 and maintained therapeutic levels up to 1 year. Cholesterol levels of AAV2/7-apoE and AAV2/8-apoE–treated mice were reduced to normal murine wild-type levels and were maintained for 1 year. At termination after 1 year, extensive atherosclerosis was present in the thoracic aortas and aortic roots of control AAV2/8-lacZ and AAV2-apoE–injected mice, but was completely prevented in both the AAV2/7 and AAV2/8-apoE–treated mice. Conclusion—We demonstrate that intravenous administration of AAV2/7- and AAV2/8-apoE vectors effectively mediated robust and sustained hepatic-specific expression of apoE and completely prevented atherosclerosis at 1 year.

ATP-binding cassette transporter G4 is highly expressed in microglia in Alzheimer's brain.

Apolipoprotein E epsilon4 is an independent risk factor for Alzheimers disease (AD) and is the main constituent of high-density lipoprotein (HDL) as a source of cholesterol in the brain. ATP-binding cassette transporter G4 (ABCG4) is one of the membrane cholesterol transporter which is implicated in HDL-mediated cholesterol efflux, but its precise localization and function in the brain has been unclear. In AD brain, ABCG4 protein was highly expressed in microglial cell that was closely located to senile plaques, whereas in non-neurological cases positive cells were not seen in cortical and nigral tissues. As well as the ABCG4 protein, ABCG4 mRNA signal was detected in microglial cell closely located to senile plaque of AD brain by in situ hybridization histochemistry. These results suggest that upregulated ABCG4 in microglia may accelerate the lipidation of apoE and HDL in the AD brain. This is the first report to show that ABCG4 is highly expressed in microglia on AD brain.

Newly developed PPAR-α agonist (R)-K-13675 inhibits the secretion of inflammatory markers without affecting cell proliferation or tube formation

Peroxisome proliferator-activated receptor-alpha (PPAR-alpha) is a key regulator of lipid and glucose metabolism and has been implicated in inflammation. The vascular effects of activator for PPARs, particularly PPAR-alpha, on vascular cells remain to be fully elucidated. Therefore, we analyzed the hypothesis that newly developed (R)-K-13675 decreases the secretion of inflammatory markers without affecting cell proliferation or tube formation. Human coronary endothelial cells (HCECs) were maintained in different doses of (R)-K-13675 under serum starvation. After 20h, the levels of monocyte chemoattractant protein-1 (MCP-1), regulated on activation, normal T expressed and secreted (RANTES), interleukin-6 (IL-6) and interferon-gamma (INF-gamma) secreted in the medium and nuclear factor kappa B (NFkappaB) in cell lysate were analyzed using enzyme-linked immunosorbent assays (ELISA). Upon treatment with (R)-K-13675 at 0, 10, 20, 50 and 100nM, with the inflammatory markers at 0nM as 100 (arbitrary units), MCP-1 levels were significantly suppressed (94+/-9, 88+/-2, 80+/-5 and 74+/-11, respectively). RANTES, IL-6 and INF-gamma levels were also significantly suppressed (RANTES: 92+/-2, 74+/-9, 64+/-7 and 60+/-2, respectively, IL-6: 97+/-2, 89+/-10, 82+/-1 and 66+/-7, respectively, INF-gamma: 98+/-7, 94+/-3, 76+/-8 and 64+/-8, respectively). NFkappaB levels were also decreased to 91+/-5, 90+/-5, 84+/-7 and 82+/-8, respectively. In addition, (R)-K-13675 did not affect HCEC proliferation or tube formation at up to 100nM. Thus, (R)-K-13675 was associated with the inhibition of inflammatory responses without affecting cell proliferation or angiogenesis, and subsequently may induce an anti-atherosclerotic effect.

Possibility of increasing cholesterol efflux by adiponectin and its receptors through the ATP binding cassette transporter A1 in HEK293T cells

A decrease in adiponectin secretion leads to the early stage of atherosclerosis. Discoidal high-density lipoproteins (HDL) accept the cholesterol that effluxes from cells expressing the ATP binding cassette transporter A1 (ABCA1) in the first step of reverse cholesterol transport (RCT). Recently, a new therapeutic strategy involving reconstituted (r)HDL has been shown to enhance RCT. Therefore, we hypothesized that adiponectin may increase the efflux associated with ABCA1 and also enhance rHDL-induced efflux in human embryonic kidney 293 (HEK293T) cells. We transfected adiponectin receptor 1 and 2 (AdipoR1 and AdipoR2) cDNA into cells. The transfected cells were labeled with [(3)H]cholesterol following cholesterol loading with or without adiponectin for 24h. The levels of cholesterol efflux were analyzed using a liquid scintillation counter. Treatment with adiponectin was associated with significantly higher levels of efflux in AdipoR1- and AdipoR2-transfected cells. Interestingly, rHDL-induced cholesterol efflux was enhanced in the presence of adiponectin. The down-regulation of adiponectin receptors using short-hairpin RNA decreased rHDL-induced cholesterol efflux with the down-regulation of ABCA1. In summary, adiponectin and its receptors increased cholesterol efflux and also enhanced rHDL-induced efflux at least partially through an ABCA1 pathway. These results suggest that adiponectin may enhance the RCT system and induce an anti-atherogenic effect.

Effects of Tolvaptan With or Without the Pre-Administration of Renin-Angiotensin System Blockers in Hospitalized Patients With Acute Decompensated Heart Failure

We examined whether tolvaptan combined with an angiotensin II receptor blocker (ARB) or angiotensin converting enzyme inhibitor (ACE-I) is more effective than tolvaptan alone in the treatment of patients with heart failure (HF). Sixty-five hospitalized patients with acute decompensated HF were included in this study. They were divided into 2 groups; an ARB/ACE-I group (n = 44, who received ARB or ACE-I before the use of tolvaptan) and a non-ARB/ACE-I group (n = 21). There were no significant differences in patient characteristics including medications at baseline between the non-ARB/ACE-I and ARB/ACE-I groups with the exception of the percentages of hypertension and ischemic heart disease. Urinary volume (UV) at baseline in the ARB/ACE-I group was slightly higher than that in the non-ARB/ACE-I group. The increase in UV after the use of tolvaptan in the non-ARB/ACE-I group was significantly higher than that in the ARB/ACE-I group. The cardiothoracic ratio and the reduction in body weight were similar between the groups after tolvaptan use. Finally, in a logistic regression analysis, a response to the use of tolvaptan was independently associated with the non-use of ARB/ACE-I, but not with age, gender, body mass index, loop diuretic, or human arterial natriuretic peptide. In conclusion, tolvaptan alone might induce an increase in UV in decompensated HF patients without ARB/ ACE-I, although the treatment of HF with ARB/ACE-I is the first choice strategy.

Visit-to-Visit Variability and Reduction in Blood Pressure After a 3-Month Cardiac Rehabilitation Program in Patients With Cardiovascular Disease

Visit-to-visit variability (VVV) in blood pressure (BP) has been shown to be a predictor of cardiovascular events. It is unknown whether CR can improve VVV in BP as well as reducing BP. We enrolled 84 patients who had cardiovascular disease (CVD) and participated in a 3-month CR program. We measured systolic and diastolic BP (SBP and DBP), pulse pressure (PP), and heart rate (HR) before exercise training at each visit and determined VVV in BP or HR expressed as the standard deviation of the average BP or HR. Patients who had uncontrolled BP at baseline and who did not change their antihypertensive drugs throughout the study period showed a significant reduction of both SBP and DBP with a decrease in PP after 3 months. Patients who did not change their antihypertensive drugs were divided into larger (L-) and smaller (S-) VVV in the SBP groups and L- and S-VVV in the DBP groups according to the average value of VVV in SBP or DBP. In the L-VVV in the SBP and DBP groups, VVV in SBP and DBP in the 1st month was significantly decreased after the 3rd month in both groups. HR at baseline was significantly decreased after 3 months. In addition, CR induced a significant increase in the level of high-density lipoprotein cholesterol (HDL-C) in blood. In conclusion, CR improved VVV in BP in patients with L-VVV in BP and evoked a significant reduction in HR and an increase in HDL-C. These effects due to the CR program may be cardioprotective.

Depressor and Anti-Inflammatory Effects of Angiotensin II Receptor Blockers in Metabolic and/or Hypertensive Patients With Coronary Artery Disease: A Randomized, Prospective Study (DIAMOND Study)

Background We compared the efficacy and safety of azilsartan to those of olmesartan in a prospective, randomized clinical trial. Methods Forty-four hypertensive patients who had coronary artery disease (CAD) were enrolled. We randomly assigned patients to changeover from their prior angiotensin II receptor blockers (ARBs) to either azilsartan or olmesartan, and followed the patients for 12 weeks. Results Office systolic blood pressure (SBP) in the azilsartan group was significantly decreased after 12 weeks. SBP and diastolic blood pressure (DBP) after 12 weeks in the azilsartan group were significantly lower than those in the olmesartan group. The percentage of patients who reached the target BP at 12 weeks (78%) in the azilsartan group was significantly higher than that at 12 weeks (45%) in the olmesartan group. There were no significant changes in pentraxin-3, high-sensitively C-reactive protein or adiponectin in blood after 12 weeks in either group. Although serum levels of creatinine (Cr) in the azilsartan group significantly increased, these changes were within the respective normal range. Conclusion In conclusion, the ability of azilsartan to reduce BP may be superior to that of prior ARBs with equivalent safety in hypertensive patients with CAD.

Recent Patient Characteristics and Medications at Admission and Discharge in Hospitalized Patients With Heart Failure

Background To improve the clinical outcome of heart failure (HF), it is important to evaluate the etiology and comorbidities of HF. We previously reported the baseline clinical characteristics and medications in hospitalized patients with HF in years 2000 - 2002 (group 2000) and 2007 - 2009 (group 2008). Methods We conducted a retrospective study of 158 patients who were hospitalized due to HF between 2012 and 2014 (group 2013) in the Department of Cardiology, Fukuoka University Hospital. We analyzed the clinical characteristics and medications at admission and discharge, and compared the findings in group 2013 to those in group 2000 and group 2008. Results The major causes of HF were ischemic heart disease, hypertensive cardiomyopathy, valvular heart disease, and dilated cardiomyopathy. The New York Heart Association classification in group 2013 was significantly higher than those in group 2000 and group 2008. There was no difference in the level of brain natriuretic peptide at admission between group 2008 and group 2013. Tolvaptan began to be administered in group 2013. The median dose of furosemide just before the use of tolvaptan was 40 mg/day. At discharge, group 2013 showed higher rates of β-blocker and aldosterone antagonist. There was no difference in the frequency of loop diuretics. The dose of carvedilol at discharge was only 6.2 ± 4.0 mg/day. Antiarrhythmic drugs and β-blocker were used more frequently in HF with reduced ejection fraction (EF) than in HF with preserved EF. Conclusions We may be able to improve the clinical outcome of HF by examining the differences in the clinical characteristics and medications at admission and discharge in hospitalized patients with HF.

Assessment of various parameters using simple non-invasive tests in patients with cardiovascular diseases with or without cardiac rehabilitation

Cardiac rehabilitation (CR) improves cardiac function and exercise capacity in patients with cardiovascular disease (CVD). Simpler techniques are needed for use by physicians in the examination room to assess the usefulness of CR. We enrolled 46 consecutive CVD patients in a CR program (CR group) and prospectively followed them for 3 months. We compared them to 18 age-, gender- and body mass index-matched CVD patients without CR (non-CR group). Various parameters were measured at baseline and after 3 months using 3 simple non-invasive tests: severity of atherosclerosis [arterial velocity pulse index and arterial pressure volume index (API)] were determined using PASESA®, an autonomic nerve total activity amount index and a coefficient of variation of the R–R interval (CVRR) were determined using eHEART®, and peripheral resistance index, pressure rate product, stroke volume and cardiac index were determined using nico®]. There were no significant differences in patient characteristics including percentages (%) of ischemic heart disease and heart failure between the non-CR and CR groups. Systolic blood pressure (SBP), diastolic BP, heart rate and API at baseline significantly decreased and CVRR at baseline significantly increased after 3 months in the CR group, but not in the non-CR group. In addition, ΔAPI (Δ = the value after 3 months minus the value at baseline) was positively associated with ΔSBP in the CR group. In conclusion, CR significantly decreased BP and improved atherosclerosis and sympathetic nerve activity. These findings suggest that simple non-invasive tests may be useful for assessing the effects of CR.