Oxidative stress is enhanced by various mechanisms. Serum oxidized low-density lipoprotein (LDL) is a useful prognostic marker in diabetic patients with coronary artery disease. To examine the effects of Theracurmin®, a highly absorbable curcumin preparation, on glucose tolerance, adipocytokines, and oxidized LDL, we conducted a double-blind placebo-controlled parallel group randomized trial in patients with impaired glucose tolerance or non-insulin-dependent diabetes mellitus. We randomly divided the patients with impaired glucose tolerance or non-insulin-dependent diabetes mellitus and stable individuals into the placebo group and the Theracurmin® (180 mg daily for 6 months) group. Of the 33 patients analyzed, 18 (14 males and 4 females) were administered placebo and 15 (9 males and 6 females) were administered Theracurmin®. The patient characteristics did not differ between the two groups. The primary endpoint, HbA1c, did not differ significantly between the two groups. However, the level of α1-antitrypsin-low-density lipoprotein (AT-LDL), the oxidized LDL, significantly increased (p = 0.024) in the placebo group from the beginning of the trial up to 6 months, although there was no such change in the Theracurmin® group. The percentage change in BMI from the beginning of the trial up to 6 months tended to be higher in the Theracurmin® group than in the placebo group. Patients in the Theracurmin® group tended to have a larger percentage change in adiponectin and LDL-C than those in the placebo group. Patients in the Theracurmin® group showed a smaller percentage change in AT-LDL than those in the placebo group. This study suggests that the highly absorbable curcumin could potentially inhibit a rise in oxidized LDL in patients with impaired glucose tolerance or non-insulin-dependent diabetes mellitus. This trial is registered with UMIN000007361.

Chronic inflammation plays a significant role in lifestyle-related diseases, such as cardiovascular diseases and obesity/impaired glucose tolerance. Curcumin is a natural extract that possesses numerous physiological properties, as indicated by its anti-inflammatory action. The mechanisms underlying these effects include the inhibition of nuclear factor-kappaB and Toll-like receptor 4-dependent signalling pathways and the activation of a peroxisome proliferator-activated receptor-gamma pathway. However, the bioavailability of curcumin is very low in humans. To resolve this issue, several drug delivery systems have been developed and a number of clinical trials have reported beneficial effects of curcumin in the management of inflammation-related diseases. It is expected that evidence regarding the clinical application of curcumin in lifestyle-related diseases associated with chronic inflammation will accumulate over time.

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A natural p300-specific histone acetyltransferase inhibitor, curcumin, may have a therapeutic potential for heart failure. However, a study of curcumin to identify an appropriate dose for heart failure has yet to be performed. Rats were subjected to a left coronary artery ligation. One week later, rats with a moderate severity of myocardial infarction (MI) were randomly assigned to 4 groups receiving the following: a solvent as a control, a low dose of curcumin (0.5 mg∙kg(-1)∙day(-1)), a medium dose of curcumin (5 mg∙kg(-1)∙day(-1)), or a high dose of curcumin (50 mg∙kg(-1)∙day(-1)). Daily oral treatment was continued for 6 weeks. After treatment, left ventricular (LV) fractional shortening was dose-dependently improved in the high-dose (25.2% ± 1.6%, P < 0.001 vs. vehicle) and medium-dose (19.6% ± 2.4%) groups, but not in the low-dose group (15.5% ± 1.4%) compared with the vehicle group (15.1% ± 0.8%). The histological cardiomyocyte diameter and perivascular fibrosis as well as echocardiographic LV posterior wall thickness dose-dependently decreased in the groups receiving high and medium doses. The beneficial effects of oral curcumin on the post-MI LV systolic function are lower at 5 compared to 50 mg∙kg(-1)∙day(-1) and disappear at 0.5 mg∙kg(-1)∙day(-1). To clinically apply curcumin therapy for heart failure patients, a precise, optimal dose-setting study is required.

The zinc finger protein GATA4 is a transcription factor involved in cardiomyocyte hypertrophy. It forms a functional complex with the intrinsic histone acetyltransferase (HAT) p300. The HAT activity of p300 is required for the acetylation and transcriptional activity of GATA4, as well as for cardiomyocyte hypertrophy and the development of heart failure. In the present study, we have identified Receptor for Activated Protein Kinase C1 (RACK1) as a novel GATA4-binding protein using tandem affinity purification and mass spectrometry analyses. We found that exogenous RACK1 repressed phenylephrine (PE)-induced hypertrophic responses, such as myofibrillar organization, increased cell size, and hypertrophy-associated gene transcription, in cultured cardiomyocytes. RACK1 physically interacted with GATA4 and the overexpression of RACK1 reduced PE-induced formation of the p300/GATA4 complex and the acetylation and DNA binding activity of GATA4. In response to hypertrophic stimulation in cultured cardiomyocytes and in the hearts of hypertensive heart disease model rats, the tyrosine phosphorylation of RACK1 was increased, and the binding between GATA4 and RACK1 was reduced. In addition, the tyrosine phosphorylation of RACK1 was required for the disruption of the RACK1/GATA4 complex and for the formation of the p300/GATA4 complex. These findings demonstrate that RACK1 is involved in p300/GATA4-dependent hypertrophic responses in cardiomyocytes and is a promising therapeutic target for heart failure.

Curcumin is a naturally occurring p300-histone acetyltransferase (p300-HAT) inhibitor that suppresses cardiomyocyte hypertrophy and the development of heart failure in experimental animal models. To enhance the therapeutic potential of curcumin against heart failure, we produced a series of synthetic curcumin analogues and investigated their inhibitory activity against p300-HAT. The compound with the strongest activity was further evaluated to determine its effects on cardiomyocyte hypertrophy and pressure overload-induced heart failure in mice. We synthesised five synthetic curcumin analogues and found that a compound we have named GO-Y030 most strongly inhibited p300-HAT activity. Furthermore, 1 μM GO-Y030, in a manner equivalent to 10 µM curcumin, suppressed phenylephrineinduced hypertrophic responses in cultured cardiomyocytes. In mice undergoing transverse aortic constriction surgery, administration of GO-Y030 at a mere 1% of an equivalently-effective dose of curcumin significantly attenuated cardiac hypertrophy and systolic dysfunction. In addition, this low dose of GO-Y030 almost completely blocked histone H3K9 acetylation and eliminated left ventricular fibrosis. A low dose of the synthetic curcumin analogue GO-Y030 effectively inhibits p300-HAT activity and markedly suppresses the development of heart failure in mice.open Scientific RepoRtS | (2020) 10:7172 | https://doi.org/10.1038/s41598-020-64207-w www.nature.com/scientificreports www.nature.com/scientificreports/ vivo, when transgenic mice overexpressing intact p300 in the heart undergo myocardial infarction surgery, they show significantly more progressive LV remodeling than wild-type mice undergoing the same surgery. However, when transgenic mice overexpressing mutant p300 that lacks HAT activity in the heart undergo the surgery, their degree of LV remodelling is similar to that of the wild-type mice 7 . These findings indicate that the HAT activity of p300 plays a key role in LV remodelling and systolic dysfunction, suggesting that this activity may be a target for heart failure treatment.Curcumin ((1E,6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)hepta-1,6-diene-3,5-dione) is a polyphenol derived from Curcuma longa. It is reported to have a variety of functions, including anticancer, antioxidant, and anti-inflammatory activities 8-10 . Additionally, Balasubramanyam et al. reported that curcumin inhibits p300-specific HAT activity 11 . We previously found both that curcumin suppresses cardiomyocyte hypertrophy by inhibiting the acetylation of GATA4 and histones, and that the oral administration of curcumin at a dose of 50 mg/kg prevents the development of heart failure in rat models of hypertension and myocardial infarction 12,13 . Curcumin is a natural compound and is now widely used as a dietary supplement 14,15 . However, to develop a novel drug for heart failure therapy in the clinical setting, it is necessary to synthesise novel curcumin analogues which have much stronger activity than natural curcumin.In the present study, we examined structure-acti...

Previous studies have shown that green tea catechins (GTCs) have beneficial effects on obesity and metabolic syndromes. In this study, we prepared kosen-cha from green tea using high pressure extraction, to reduce the astringent taste of the green tea. We identified a large quantity of polymerized GTCs in kosen-cha. To investigate the effects of kosen-cha containing polymerized GTCs in obese Japanese patients, we designed an open-label pilot study in which 6 obese subjects (body mass index (BMI) >25 kg/m 2) were administered kosen-cha (5 g/L/d) for 12 weeks. Body composition, serum lipids, insulin resistance, vascular functions, and cardiac hypertrophy were measured before and 12 weeks after kosen-cha administration. Kosen-cha showed no significant adverse effects on the patients. Body weights, BMI, waist circumferences, serum triglyceride (TG) levels, and homeostasis model assessment as an index of insulin resistance (HOMA-IR) levels were significantly decreased after the 12 weeks of administration. Flow-mediated dilation (FMD) (p 0.0214), brachial-ankle pulse wave velocity (baPWV)(p 0.0141), left ventricular mass indexes (p 0.0120), and plasma brain natriuretic peptide (BNP) (p 0.0144) were significantly improved. Overall, kosen-cha reduced obesity and improved insulin resistance, vascular function, and cardiac hypertrophy, indicating its preventive potential in obesity and metabolic syndrome.

The natural compound, curcumin (CUR), possesses several pharmacological properties, including p300-specific histone acetyltransferase (HAT) inhibitory activity. In our previous study, we demonstrated that CUR could prevent the development of cardiac hypertrophy by inhibiting p300-HAT activity. Other major curcuminoids isolated from Curcuma longa including demethoxycurcumin (DMC) and bisdemethoxycurcumin (BDMC) are structural analogs of CUR. In present study, we first confirmed the effect of these three curcuminoid analogs on p300-HAT activity and cardiomyocyte hypertrophy. Our results showed that DMC and BDMC inhibited p300-HAT activity and cardiomyocyte hypertrophy to almost the same extent as CUR. As the three compounds have structural differences in methoxy groups at the 3-position of their phenol rings, our results suggest that these methoxy groups are not involved in the inhibitory effects on p300-HAT activity and cardiac hypertrophy. These findings provide useful insights into the structure-activity relationship and biological activity of curcuminoids for p300-HAT activity and cardiomyocyte hypertrophy.