Olmesartan is an angiotensin II receptor blocker with an inhibitory effect on angiotensin-converting enzyme.

Angiotensin II receptor blockers (ARBs) are widely used for the treatment of hypertension. It is believed that treatment with an ARB increases the level of plasma angiotensin II (Ang II) because of a lack of negative feedback on renin activity. However, Ichikawa (Hypertens Res 2001; 24: 641-646) reported that long-term treatment of hypertensive patients with olmesartan resulted in a reduction in plasma Ang II level, though the mechanism was not determined. It has been reported that angiotensin 1-7 (Ang-(1-7)) potentiates the effect of bradykinin and acts as an angiotensin-converting enzyme (ACE) inhibitor. It is known that ACE2, which was discovered as a novel ACE-related carboxypeptidase in 2000, hydrolyzes Ang I to Ang-(1-9) and also Ang II to Ang-(1-7). It has recently been reported that olmesartan increases plasma Ang-(1-7) through an increase in ACE2 expression in rats with myocardial infarction. We hypothesized that over-expression of ACE2 may be related to a reduction in Ang II level and the cardioprotective effect of olmesartan. Administration of 0.5 mg/kg/day of olmesartan for 4 weeks to 12-week-old stroke-prone spontaneously hypertensive rats (SHRSP) significantly reduced blood pressure and left ventricular weight compared to those in SHRSP given a vehicle. Co-administration of olmesartan and (D-Ala7)-Ang-(1-7), a selective Ang-(1-7) antagonist, partially inhibited the effect of olmesartan on blood pressure and left ventricular weight. Interestingly, co-administration of (D-Ala7)-Ang-(1-7) with olmesartan significantly increased the plasma Ang II level (453.2+/-113.8 pg/ml) compared to olmesartan alone (144.9+/-27.0 pg/ml, p<0.05). Moreover, olmesartan significantly increased the cardiac ACE2 expression level compared to that in Wistar Kyoto rats and SHRSP treated with a vehicle. Olmesartan significantly improved cardiovascular remodeling and cardiac nitrite/ nitrate content, but co-administration of olmesartan and (D-Ala7)-Ang-(1-7) partially reversed this anti-remodeling effect and the increase in nitrite/nitrate. These findings suggest that olmesartan may exhibit an ACE inhibitory action in addition to an Ang II receptor blocking action, prevent an increase in Ang II level, and protect cardiovascular remodeling through an increase in cardiac nitric oxide production and endogenous Ang-(1-7) via over-expression of ACE2.     

Effects of hypertension and type 2 diabetes mellitus on the risk of total cardiovascular events in Japanese patients with hypercholesterolemia: implications from the Japan Lipid Intervention Trial (J-LIT).

Hyperlipidemia, hypertension, and diabetes mellitus (DM) are well-established risk factors for cardiovascular disease. We analyzed the cardiovascular events in hyperlipidemic patients with or without DM who were administered open-labeled simvastatin in groups stratified by blood pressure level using data from the Japan Lipid Intervention Trial (J-LIT). Hyperlipidemic patients with DM (n=6,288) had significantly more cardiovascular events than those without DM (n=33,933). The incidence rates of total cardiovascular events in the Non-DM and DM groups were 15.40 and 25.76 per 1,000 patients for the 6-year period, respectively. The relative risk of total cardiovascular events in the DM vs. the Non-DM group was 1.68, and the relative risk was significantly higher in the DM than in the Non-DM group. The relative risks of total cardiovascular events were significantly higher in DM and Non-DM patients whose systolic blood pressure (SBP) was greater than or equal to 130 mmHg compared to that of Non-DM patients whose SBP was less than 130 mmHg, and in DM and Non-DM patients whose diastolic blood pressure (DBP) was greater than or equal to 80 mmHg compared to that of Non-DM patients whose DBP was less than 80 mmHg. In all groups stratified by SBP and DBP, relative risks of total cardiovascular events were higher in DM patients than in Non-DM patients. For patients with hypercholesterolemia and DM, blood pressure should be strictly controlled in order to prevent both coronary events and stroke. These results are in good agreement with the JNC 7 and the ESH/ESC guidelines for DM patients, which recommended that the SBP and DBP be less than 130 and 80 mmHg, respectively.     

Gene polymorphism of myospryn (cardiomyopathy-associated 5) is associated with left ventricular wall thickness in patients with hypertension.

We examined a gene polymorphism of a novel Z-disc-related protein, myospryn (cardiomyopathy-associated 5). We focused on one haplotype block associated with a tag single nucleotide polymorphism (SNP) that covered 16 of 27 coding SNPs with linkage disequilibrium (minor allele frequency 0.413). Screening a myospryn polymorphism (K2906N) in a general health check-up of a rural Japanese population revealed an association with cardiac diseases (p=0.0082). In further analysis of the interaction between K2906N and cardiac function in patients, K2906N was associated with the anteroseptal wall thickness of the left ventricle in a recessive model (p=0.0324) and with the ratio of the peak velocity of the early diastolic filling wave to the peak velocity of atrial filling (A/E) (p=0.0278). In an association study based on left ventricular wall thickness, we found a significant difference in the K2906N genotype between controls and patients with cardiac hypertrophy. These results suggest that the K2906N polymorphism could be clinically associated with left ventricular hypertrophy and diastolic dysfunction independent of known parameters. Although the precise mechanism underlying this association remains to be elucidated, treatment with angiotensin II induced an increase in heart myospryn mRNA level in vitro and in vivo. Our results suggest that the polymorphism of myospryn is associated with left ventricular hypertrophy, and an association between a Z-disc protein and cardiac adaptation in response to pressure overload.     

Alcohol drinking and high blood pressure: data from a 1980 national cardiovascular survey of Japan.

Many epidemiological cross-sectional studies have confirmed that alcohol drinking is related to high blood pressure. However, the impact of alcohol drinking on high blood pressure in the general population including older people has only been reported on in a few studies. The association between alcohol drinking and blood pressure or the prevalence of hypertension was examined using cross-sectional data of 4795 men and 6102 women aged 30-94, randomly selected from the Japanese population in 1980. The response rates were 74 and 84% for men and women, respectively. The prevalence of hypertension adjusted for body mass index (BMI, kg/m2) was significantly higher in everyday male drinkers than in male non-drinkers from the youngest age group (30-39 years) to oldest age group (70 years and over). A relationship between alcohol and blood pressure was found only in the youngest age group (30-39 years) of female drinkers. In each 10-year age-group of men, the BMI-adjusted systolic and diastolic blood pressures in everyday drinkers were 7-10 and 4-6 mmHg higher than those in non-drinkers. The relationship between alcohol and blood pressure in men was confirmed by multiple regression analysis adjusting for age and BMI in both younger (30-59 years) and older (60-94 years) people. The impact of alcohol drinking on blood pressure in men should be taken into account in the primary prevention of blood pressure related diseases and in the treatment of hypertension in both younger and older people.     

Comparison of lidocaine with and without bupivacaine for local dental anesthesia.

The purpose of this study was to investigate the effectiveness of a combination of bupivacaine and lidocaine and that of lidocaine alone for local dental anesthesia. First, on different days, healthy volunteers were given 2% lidocaine with 1/80,000 epinephrine or 2% lidocaine with 1/80,000 epinephrine + 0.5% bupivacaine, after which pain was produced with a pulp tester. No difference was found in the time until onset of anesthetic effect between the preparations. However, the duration of anesthetic effect was longer with both lidocaine and bupivacaine than with lidocaine alone. Next, patients undergoing dental surgery were given one of the anesthetic preparations, after which serum concentrations of the anesthetics and epinephrine were measured. The maximal serum concentration of lidocaine was higher and was reached sooner after injection in patients receiving lidocaine alone (1.74 microgram/ml after 5 min) than in patients receiving both anesthetics (0.85 microgram/ml after 3 min). The mean maximal serum concentration of lidocaine was higher in patients receiving lidocaine alone (1.77 +/- 0.03 microgram/ml) than in those receiving both anesthetics (0.99 +/- 0.45 microgram/ml). Furthermore, the mean plasma concentration of epinephrine 1 min after injection was significantly higher in patients receiving lidocaine alone (0.671 ng/ml) than in patients receiving both lidocaine and bupivacaine (0.323 ng/ml). The results of this study suggest that the combination of lidocaine with epinephrine and bupivacaine produces lower systemic levels of the anesthetic and epinephrine and a longer duration of activity than lidocaine with epinephrine alone for local dental anesthesia.