Effect of Early Normotension with Olmesartan on Rho-kinase Activity in Hypertensive Patients

Hydrochlorothiazide Reduces Cardiac Hypertrophy, Fibrosis and Rho-Kinase Activation in DOCA-Salt Induced Hypertension

BACKGROUND

Thiazides are one of the most common antihypertensive drugs used for hypertension treatment and hydrochlorothiazide (HCTZ) is the most frequently used diuretic for hypertension treatment. The Rho/Rho-kinase (ROCK) path plays a key function in cardiovascular remodeling. We hypothesized that in preclinical hypertension HCTZ reduces myocardial ROCK activation and consequent myocardial remodeling.

METHODS

The preclinical model of deoxycorticosterone (DOCA)-salt hypertension was used (Sprague-Dawley male rats). After 3 weeks, in 3 different groups: HCTZ, the ROCK inhibitor fasudil or spironolactone was added (3 weeks). After 6 weeks myocardial hypertrophy and fibrosis, cardiac levels of profibrotic proteins, mRNA levels (RT PCR) of pro remodeling and pro oxidative molecules and ROCK activity were determined.

RESULTS

Blood pressure, myocardial hypertrophy and fibrosis were reduced significantly by HCTZ, fasudil and spironolactone. In the heart, increased levels of the pro-fibrotic proteins Col-I, Col-III and TGF-β1 and gene expression of pro-remodeling molecules TGF-β1, CTGF, MCP-1 and PAI-1 and the pro-oxidative molecules gp91phox and p22phox were significantly reduced by HCTZ, fasudil and spironolactone. ROCK activity in the myocardium was increased by 54% (P < 0.05) as related to the sham group and HCTZ, spironolactone and fasudil, reduced ROCK activation to control levels.

CONCLUSIONS

HCTZ reduced pathologic LVH by controlling blood pressure, hypertrophy and myocardial fibrosis and by decreasing myocardial ROCK activation, expression of pro remodeling, pro fibrotic and pro oxidative genes. In hypertension, the observed effects of HCTZ on the myocardium might explain preventive outcomes of thiazides in hypertension, specifically on LVH regression and incident heart failure.

Rho kinase cascade activation in circulating leukocytes in patients with diabetes mellitus type 2

Background

The intracellular ROCK signaling pathway is an important modulator of blood pressure and of cardiovascular and renal remodeling when Rho-kinase activity is increased. Besides, in preclinical models of diabetes, ROCK activation has also a role in abnormal glucose metabolism as well as in subsequent vascular and myocardial dysfunction. In humans, there are a few data assessing ROCK activation in patients with type 2 diabetes mellitus (T2D) and no studies assessing upstream/downstream components of the ROCK pathway. We assessed here levels of ROCK activation and some of the RhoA/ROCK cascade molecules in peripheral blood mononuclear cells (PBMCs) in T2D patients under current treatment.

Methods

Cross-sectional observational study comparing 28 T2D patients under current antidiabetic treatment with 31 consecutive healthy subjects, matched by age and gender. Circulating levels of malondialdehyde, angiotensin II and inflammatory cytokines IL-6 and IL-8 were determined in all subjects. ROCK activation in PMBCs, upstream and downstream cascade proteins, and levels of the proinflammatory molecules VCAM, ICAM-1 and IL-8 were determined in their PMBCs by Western blot.

Results

Compared to healthy controls, ROCK activation in T2D patients measured by 2 direct ROCK targets in PBMCs was increased by 420 and 570% (p < 0001) and it correlated significantly with serum glucose levels. p38 MAPK phosphorylation (downstream from ROCK) and JAK-2 (upstream from ROCK) were significantly higher in the T2D patients by 580% and 220%, respectively. In T2D patients, significantly increased PBMC levels of the proinflammatory molecules VCAM-1, ICAM-1 and IL-8 were observed compared to control subjects (by 180%, 360% and 260%, respectively). Circulating levels of Ang II and MDA were significantly higher in T2D patients by 29 and 63%, respectively.

Conclusions

T2D patients under treatment with glucose-lowering drugs, antihypertensive treatment as well as with statins have significantly increased ROCK activation in their circulating leukocytes along with higher phosphorylation of downstream cascade proteins despite pharmacologic treatment, along with increased plasma angiotensin II and MDA levels. ROCK inhibition might have an additional role in the prevention and treatment of T2D.

Urotensin-#receptor antagonist SB-706375 protected isolated rat heart from ischaemia-reperfusion injury by attenuating myocardial necrosis via RhoA/ROCK/RIP3 signalling pathway

SB-706375 is a selective receptor antagonist of human urotensin-II (hU-II), which can block the aorta contraction induced by hU-II in rats. The effect of SB-706375 on myocardial ischaemia-reperfusion (I/R) injury is unclear. The major objective of this study was to investigate whether SB-706375 has a protective effect on myocardial I/R injury in rats and explore its possible mechanisms. Isolated hearts of Adult Sprague-Dawley were perfused in a Langendorff apparatus, and haemodynamic parameters, lactate dehydrogenase (LDH), creatine phosphokinase-MB (CK-MB), cardiac troponin I (cTnI), RhoA, and the protein expressions of U-II receptor (UTR), receptor-interacting protein 3 (RIP3), Rho-associated coiled-coil-containing protein kinase 1 (ROCK1) and Rho-associated coiled-coil-containing protein kinase 2 (ROCK2) were assessed. We found that SB-706375 (1 × 10-6 and 1 × 10-5 mol/L) significantly inhibited the changes of haemodynamic parameters and reduced LDH and CK-MB activities and also cTnI level in the coronary effluents in the heart subjected to myocardial I/R injury. Further experiments studies showed that SB-706375 obviously prevented myocardial I/R increased RhoA activity and UTR, RIP3, ROCK1, and ROCK2 protein expressions. ROCK inhibition abolished the improving effect of SB-706375 on myocardial I/R-induced haemodynamic change in the isolated perfused rat heart. These findings suggested that SB-706375 provides cardio-protection against I/R injury in isolated rats by blocking UTR-RhoA/ROCK-RIP3 pathway.