Antihypertensive action of 2-hydroxyoleic acid in SHRs via modulation of the protein kinase A pathway and Rho kinase

Olive oil consumption leads to high monounsaturated fatty acid intake, especially oleic acid, and has been associated with a reduced risk of hypertension. However, the molecular mechanisms and contribution of its different components to lower blood pressure (BP) require further evaluation. Here, we examined whether a synthetic, non-beta-oxidation-metabolizable derivative of oleic acid, 2-hydroxyoleic acid (2-OHOA), can normalize BP in adult spontaneously hypertensive rats (SHRs) and whether its antihypertensive action involves cAMP-dependent protein kinase A (PKA) and Rho kinase, two major regulators of vascular smooth muscle contraction. Oral administration of 2-OHOA to SHRs induced sustained systolic BP decreases in a time-dependent (1-7 days) and dose-dependent (100-900 mg/kg every 12 h) manner. After 7 days of treatment with 2-OHOA (600 mg/kg), the systolic BP of SHRs was similar to that of normotensive Wistar Kyoto rats, returning to its initial hypertensive level after withdrawal of 2-OHOA. This treatment strongly increased the protein expression of the catalytic and regulatory RIalpha and RIIalpha PKA subunits as well as PKA activity in aortas from SHRs. Consistently, administration of the PKA inhibitor 8-bromo adenosine-3',5'-cyclic monophosphorothioate, Rp isomer, to 2-OHOA-treated SHRs induced a pronounced reversal (up to 59%) of the antihypertensive effect of 2-OHOA. Additionally, 2-OHOA completely reversed the pathological overexpression of aortic Rho kinase found in SHRs, suppressing the vasoconstrictory Rho kinase pathway.     

Association study of AGER gene polymorphism and hypertension in Han Chinese population

Background

Advanced glycation end products (AGEs) are produced by non-enzymatic glycation or glycoxidation of proteins, lipids and nucleic acids. The bond of AGEs and the receptor of AGE (AGER) in a pro-oxidant environment could induce immune and inflammation reaction involved in progress of microvascular disease. Accumulated evidence warrant further study on AGE–AGER pathway and genetic susceptibility to hypertension (HT).

Methods

We designed a two-stage association study to evaluate the association of AGER polymorphism and HT. In stage 1, seven tagSNPs were tested in 524 cases and 531 controls and the significant SNPs (P < 0.05) would enter into stage 2 including 807 cases and 869 controls. Furthermore, joint analysis was performed for all 2731 subjects including 1331 cases and 1400 controls, and meta-analysis was applied to evaluate combined estimations from the subgroups of stage 1 and stage 2.

Results

In stage 1, rs204994 had significant association with HT (P < 0.05) and enter stage 2. Neither joint analysis nor meta-analysis found statistical association of rs204994 with HT after adjusted for the covariates in the whole population. However, further stratification analysis found that rs204994 was significantly associated with HT in < 50 years and ≥ 50 years groups, ORs (95%CI) of dominant model were 1.623 (1.054–2.500) and 0.721 (0.546–0.952) respectively. No significant correlation was found between blood pressure and the polymorphisms of rs204994.

Conclusions

Our data suggests that age might modulate the genetic effects of variation of rs204994 in AGER on HT and further replications in other populations and functional studies should be warranted.