Changes of cardiac function, RAGE expression and calcium dysregula-tion in type 2 diabetic rats / 中国病理生理杂志

AIM:To investigate the changes of cardiac structure and function in rats with type 2 diabetic melli-tus(T2DM),and to explore the mechanisms underlying diabetic cardiomyopathy.METHODS:The cardiac structure and function were measured by echocardiography in Zucker diabetic fatty(ZDF)rats and their control Zucker lean(ZL)rats. The size of the cardiomyocytes was determined by wheat germ agglutinin staining.The protein expression of atrial natriuretic peptide(ANP),β-myosin heavy chain(β-MHC), receptor for advanced glycation end products(RAGE), L-type cal-cium channel α1C subunit(CaV1.2)and Orai1 was assessed by Western blot.RESULTS:Compared with the ZL control rats,the thickness of left ventricular wall,ejection fraction(EF),fractional shortening(FS)and the sizes of cardiomyo-cytes were significantly increased,and diastolic function was decreased in the ZDF rats(P<0.05).The protein expression of β-MHC, ANP, RAGE and Orai1 was increased, while the expression of Ca V1.2 was decreased in ZDF rats(P <0.05).CONCLUSION:T2DM rats show the prominent features including cardiomyocyte hypertrophy,ventricular hyper-trophy and compensatory enhancement of cardiac function, and the Ca2+handling and increase in RAGE expression may play important roles in the processes.

Genetic and epigenetic predispositions underlying cardiovascular outcomes among patients treated with clopidogrel and aspirin / 中国药理学与毒理学杂志

Coronary artery disease (CAD)is a major cause of death and disability worldwide, and consumes a considerable amount of medical resources every year.Clopidogrel is a first-line antiplate-let therapy for CHD, butit is associated with substantial variability in PK and pharmacodynamics re-sponse. To date, gene variants explain only a smallproportion of the variability.The study aimed to identify new genetic loci-modifying antiplatelet response to clopidogrel in Chinese patients with CAD by a systematic analysis combining antiplatelet effects and PK, and further to investigate the PON1 gene promoter DNA methylation and genetic variations possibly influencing clinical outcomes in pa-tients undergoing PCI. We identified novel variants in two transporter genes (SLC14A2rs12456693, ATP-binding cassette [ABC]A1 rs2487032) and in N6AMT1 (rs2254638) associated with P2Y12 reac-tion unit (PRU) and plasma active metabolite (H4) concentration. These new variants dramatically im-proved the predictability of PRU variability to 37.7％. The associations between these loci and PK pa-rameters of clopidogrel and H4 were observed in additional patients, and its function on the activation of clopidogrel was validated in liver S9 fractions (P<0.05). Rs2254638 was further identified to exert a marginal risk effect formajor adverse cardiac events in an independent cohort.Multivariate logistic regression analysis indicated that PON1methylation level at CpG site-161 (OR=0.95; 95％ CI=0.92–0.98;P<0.01)and the use of angiotensin converting enzyme inhibitors(OR=0.48;95％ CI=0.26–0.89;P<0.01) were associated with decreased risk of bleeding events. In conclusion, new genetic variants were systematically identified as risk factors for the reduced efficacy of clopidogrel treatment.The ab-normal expression of DNA methylation-regulating key genes in the pharmacokinetic and pharmacody-namics pathways of clopidogrel and aspirin may modify clinical outcomes in dual antiplatelet-treated pa-tients undergoing PCI.

L-type calcium channel involved in heterogeneity of arterial constriction in different organs of rats / 中国药理学通报

Aim To study whether there was arterial heterogeneity and association with L-type calcium channel (LCC) in different parts of arteries in re-sponse to certain vasoconstrictor. Methods The aor-ta, renal arteries and coronary arteries were dissected from rats. Arterial ring contractions induced by pheny-lephrine (Phe), 5-hydroxyl tryptamine (5-HT) or U46619 in concentration-dependent manner were meas-ured using the Multi Myograph system and the response to nifedipne was observed. Results (1) Phe had no obvious effect on the tension of coronary artery,but in-duced concentration-dependent vasoconstriction in aor-ta and renal artery,and pEC50of aorta was significantly higher than that of renal artery (P<0.05). The inhi-bition rate of nifedipine on the aortic contractile re-sponses was significantly higher than that of renal arter-y (P<0.05). (2) The contraction induced by 5-HT on aorta was not obvious, but was significant on renal artery and coronary artery. The inhibitory rate of nife-dipine on coronary artery vasoconstriction was signifi-cantly higher than that of renal artery (P <0.05). (3) U46619 could induce aorta,renal artery and coro-nary artery concentration- dependent contraction, but the Emaxof them were both higher than that of renal ar-tery (P<0.05). And the pEC50of aorta was the lar-gest (P<0.05). Nifedipine significantly inhibited the contraction of aorta, renal artery and coronary artery induced by U46619 with the greatest inhibitory rate on the coronary artery vasoconstriction and minimal inhibi-tion on aortic vasoconstriction. Conclusions The re-sponse to certain vasoconstrictor is different among aor-ta, renal artery and coronary artery in rats, and the contraction mediated by L-type calcium channel is also different.