Cyclooxygenase-2 inhibitors attenuate increased blood pressure in renovascular hypertensive models, but not in deoxycorticosterone-salt hypertension

The Protective Effect of Aspirin against Myocardial Hypertrophy in Rats

The protective effect of aspirin against myocardial hypertrophy (MH) was studied. Model rats of pressure overload MH were prepared by abdominal aortic coarctation. Rats were randomly divided into the sham group (n = 9), MH model group (n = 9), and MH+aspirin group (n = 9), which was, respectively, divided into the 4-week group and 8-week group according to the time of intragastric administration. Arterial blood pressure and left ventricular mass index (LVMI) were measured. Changes in myocardial tissue structure were observed by HE staining, Masson staining, and reticular fiber staining. Cardiomyocyte apoptosis was detected by TUNEL assay. The levels of TNF-α, IL-10, TXA2, and PGI2 in myocardium and plasma were detected by ELISA. The arterial blood pressure in the MH model group was significantly higher than that in the 4- and 8-week sham groups, but that in the MH+aspirin group was significantly lower than that in the MH model group. At 4 and 8 weeks, the LVWI in the MH model group was significantly higher than that in the sham group, but it was significantly reduced after aspirin treatment. The myocardial cell hypertrophy was obvious, collagen fibers were proliferated, and reticular fibers were reduced in the 4- and 8-week MH model groups. Compared with the MH model groups, myocardial cells in the MH+aspirin groups were significantly reduced, the collagen fiber content was significantly reduced, and the reticular fiber content was increased. The apoptotic cardiomyocytes in the 4- and 8-week MH model groups were obviously increased. The apoptosis of myocardial cells in the MH+aspirin groups was obviously decreased. The TNF-α levels in the myocardial tissue of the 4- and 8-week MH model groups were significantly increased, while those of the MH+aspirin groups were significantly decreased. There was no significant change in the IL-10 level or PGI2 level at 4 weeks. At 8 weeks, the PGI2 level was significantly decreased in the MH model group while significantly increased in the MH+aspirin group. The TXA2 levels were significantly increased in the 4- and 8-week MH model groups and those in the 4- and 8-week MH+aspirin groups were significantly lower. Aspirin has an anti-inflammatory effect, can effectively reduce the expression of inflammatory factors, inhibit myocardial apoptosis, and has a certain protective effect against MH.

Cardio-renal safety of non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most widely used therapeutic class in clinical medicine. These are sub-divided based on their selectivity for inhibition of cyclooxygenase (COX) isoforms (COX-1 and COX-2) into: (1) non-selective (ns-NSAIDs), and (2) selective NSAIDs (s-NSAIDs) with preferential inhibition of COX-2 isozyme. The safety and pathophysiology of NSAIDs on the renal and cardiovascular systems have continued to evolve over the years following short- and long-term treatment in both preclinical models and humans. This review summarizes major learnings on cardiac and renal complications associated with pharmaceutical inhibition of COX-1 and COX-2 with focus on preclinical to clinical translatability of cardio-renal data.

Genetic ablation of NFAT5/TonEBP in smooth muscle cells impairs flow- and pressure-induced arterial remodeling in mice

The arterial wall adapts to alterations in blood flow and pressure by remodeling the cellular and extracellular architecture. Biomechanical stress of vascular smooth muscle cells (VSMCs) in the media is thought to precede this process and promote their activation and subsequent proliferation. However, molecular determinants orchestrating the transcriptional phenotype under these conditions have been insufficiently studied. We identified the transcription factor, nuclear factor of activated T cells 5 (NFAT5; or tonicity enhancer-binding protein) as a crucial regulatory element of mechanical stress responses of VSMCs. Here, the relevance of NFAT5 for arterial growth and thickening is investigated in mice upon inducible smooth muscle cell (SMC)-specific genetic ablation of Nfat5. In cultured mouse VSMCs, loss of Nfat5 inhibits the expression of gene sets involved in the control of the cell cycle and the interaction with the extracellular matrix and cytoskeletal dynamics. In vivo, SMC-specific knockout of Nfat5 did not affect the general vascular architecture and blood pressure levels under baseline conditions. However, proliferation of VSMCs and the thickening of the arterial wall were inhibited during both flow-induced collateral remodeling and hypertension-mediated arterial hypertrophy. Whereas originally described as a hypertonicity-responsive transcription factor, these findings identify NFAT5 as a novel molecular determinant of biomechanically induced phenotype changes of VSMCs and wall stress-induced arterial remodeling processes.-Arnold, C., Feldner, A., Zappe, M., Komljenovic, D., De La Torre, C., Ruzicka, P., Hecker, M., Neuhofer, W., Korff, T. Genetic ablation of NFAT5/TonEBP in smooth muscle cells impairs flow- and pressure-induced arterial remodeling in mice.

Cyclooxygenase-2 Inhibition Limits Angiotensin II-Induced DNA Oxidation and Protein Nitration in Humans

Compared to other cyclooxygenase-2 inhibitors, celecoxib is associated with a lower cardiovascular risk, though the mechanism remains unclear. Angiotensin II is an important mediator of oxidative stress in the pathophysiology of vascular disease. Cyclooxygenase-2 may modify the effects of angiotensin II though this has never been studied in humans. The purpose of the study was to test the effects of selective cyclooxygenase-2 inhibition on plasma measures of oxidative stress, the vasoconstrictor endothelin-1, and nitric oxide metabolites, both at baseline and in respose to Angiotensin II challenge in healthy humans. Measures of 8-hydroxydeoxyguanosine, advanced oxidation protein products, nitrotyrosine, endothelin-1, and nitric oxide metabolites were assessed from plasma samples drawn at baseline and in response to graded angiotensin II infusion (3 ng/kg/min × 30 min, 6 ng/kg/min × 30 min) before and after 14 days of cyclooxygenase-2 inhibition in 14 healthy subjects (eight male, six female) in high salt balance, a state of maximal renin angiotensin system suppression. Angiotensin II infusion significantly increased plasma oxidative stress compared to baseline (8-hydroxydeoxyguanosine; +17%; advanced oxidation protein products; +16%), nitrotyrosine (+76%). Furthermore, levels of endothelin-1 levels were significantly increased (+115%) and nitric oxide metabolites were significantly decreased (−20%). Cycloxygenase-2 inhibition significantly limited the increase in 8-hydroxydeoxyguanosine, nitrotyrosine and the decrease in nitric oxide metabolites induced by angiotensin II infusion, though no changes in advanced oxidation protein products and endothelin-1 concentrations were observed. Cyclooxygenase-2 inhibition with celecoxib partially limited the angiotensin II-mediated increases in markers of oxidative stress in humans, offering a potential physiological pathway for the improved cardiovascular risk profile of this drug.

Interaction of the renin angiotensin and cox systems in the kidney

Cyclooxygenase-2 (COX-2) plays an important role in mediating actions of the renin-angiotensin system (RAS). This review sheds light on the recent developments regarding the complex interactions between components of RAS and COX-2; and their implications on renal function and disease. COX-2 is believed to counter regulate the effects of RAS activation and therefore counter balance the vasoconstriction effect of Ang II. In kidney, under normal conditions, these systems are essential for maintaining a balance between vasodilation and vasoconstriction. However, recent studies suggested a pivotal role for this interplay in pathology. COX-2 increases the renin release and Ang II formation leading to increase in blood pressure. COX-2 is also associated with diabetic nephropathy, where its upregulation in the kidney contributes to glomerular injury and albuminuria. Selective inhibition of COX-2 retards the progression of renal injury. COX-2 also mediates the pathologic effects of the (Pro)renin receptor (PRR) in the kidney. In summary, this review discusses the interaction between the RAS and COX-2 in health and disease.

Attenuation of renovascular hypertension by cyclooxygenase-2 inhibitor partly through ANP release

Angiotensin II (Ang II) is an important inflammatory mediator. Ang II induces cyclooxygenase-2 (COX-2) expression and prostaglandin F2α release followed by cardiac hypertrophy. Inhibition of COX-2 may modulate high blood pressure but controversy still exists. The aim of this study was to determine the role of COX-2 in the regulation of blood pressure and to define the mechanisms in two kidney one-clip hypertensive (2K1C) rats. Chronic treatment with nimesulide or NS-398 (5 mg/kg/day) for 3 weeks lowered high blood pressure and cardiac hypertrophy with decreased expression levels of cardiac hypertrophy markers [atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP)], Ang type 1 receptor, urotensin II, and urotensin II receptor in 2K1C rats. Plasma level of ANP was markedly increased and plasma levels of Ang II and aldosterone were decreased by treatment with nimesulide or NS-398. In both in vitro and in vivo experiments, nimesulide or NS-398 augmented ANP release in 2K1C rats. The inhibitory effect of NS-398 on blood pressure was attenuated by the pretreatment with natriuretic peptide receptor-A (NPR-A) antagonist (A71915, 30 μg/kg/day). These results suggest that chronic treatment with nimesulide or NS-398 attenuated hypertension and cardiac hypertrophy partly through ANP release in 2K1C rats.

Role of cyclooxygenase-2 in the development of interstitial fibrosis in kidneys following unilateral ureteral obstruction in mice

Unilateral ureteral obstruction (UUO) induced tubulointerstitial fibrosis in kidneys mimics the pathogenesis of chronic kidney diseases and is considered a suitable model for studying the mechanisms leading to fibrosis. To study the role of cyclooxygenase-2 (COX-2) in kidney fibrosis, we investigated whether a selective COX-2 inhibitor, celecoxib, affected renal interstitial fibrosis during UUO in mice. To induce UUO, the left proximal ureter was ligated in male C57BL/6 mice. The mice were fed a diet with or without celecoxib from the day of UUO induction. Following UUO, the renal pelvis was observed to be dilated and the kidney cortex was significantly thinner than that of sham-operated mice. Immunofluorescent staining of type I, III, and IV collagen in UUO kidneys revealed that interstitial collagen deposition was significantly increased in the celecoxib-treated group. Expression of type I, III, and IV collagen in UUO kidneys was also significantly higher in the celecoxib-treated group than in the vehicle-treated group. In the celecoxib-treated group, mRNA levels of TGF-β/FGF-2 were also significantly higher than those in the vehicle-treated group. The present study demonstrates that COX-2 plays a protective role against fibrosis in UUO kidneys and suggests that supplementation of COX-2 products, such as PG analogues, will be a good option for preventing interstitial fibrosis.

Brain-targeted angiotensin-converting enzyme 2 overexpression attenuates neurogenic hypertension by inhibiting cyclooxygenase-mediated inflammation

Overactivity of the renin-angiotensin system, oxidative stress, and cyclooxygenases (COX) in the brain are implicated in the pathogenesis of hypertension. We previously reported that angiotensin-converting enzyme 2 (ACE2) overexpression in the brain attenuates the development of deoxycorticosterone acetate-salt hypertension, a neurogenic hypertension model with enhanced brain renin-angiotensin system and sympathetic activity. To elucidate the mechanisms involved, we investigated whether oxidative stress, mitogen-activated protein kinase signaling and cyclooxygenase (COX) activation in the brain are modulated by ACE2 in neurogenic hypertension. Deoxycorticosterone acetate-salt hypertension significantly increased expression of Nox-2 (+61±5%), Nox-4 (+50±13%), and nitrotyrosine (+89±32%) and reduced activity of the antioxidant enzymes, catalase (-29±4%) and superoxide dismutase (-31±7%), indicating increased oxidative stress in the brain of nontransgenic mice. This increased oxidative stress was attenuated in transgenic mice overexpressing ACE2 in the brain. Deoxycorticosterone acetate-salt-induced reduction of neuronal nitric oxide synthase expression (-26±7%) and phosphorylated endothelial nitric oxide synthase/total endothelial nitric oxide synthase (-30±3%), and enhanced phosphorylation of protein kinase B and extracellular signal-regulated kinase 1/2 in the paraventricular nucleus, were reversed by ACE2 overexpression. In addition, ACE2 overexpression blunted the hypertension-mediated increase in gene and protein expression of COX-1 and COX-2 in the paraventricular nucleus. Furthermore, gene silencing of either COX-1 or COX-2 in the brain, reduced microglial activation and accompanied neuroinflammation, ultimately attenuating Deoxycorticosterone acetate-salt hypertension. Together, these data provide evidence that brain ACE2 overexpression reduces oxidative stress and COX-mediated neuroinflammation, improves antioxidant and nitric oxide signaling, and thereby attenuates the development of neurogenic hypertension.

Prostaglandin receptor EP3 mediates growth inhibitory effect of aspirin through androgen receptor and contributes to castration resistance in prostate cancer cells

Although numerous epidemiological studies show aspirin to reduce risk of prostate cancer, the mechanism of this effect is unclear. Here, we first confirmed that aspirin downregulated androgen receptor (AR) and prostate-specific antigen in prostate cancer cells. We also found that aspirin upregulated prostaglandin receptor subtype EP3 but not EP2 or EP4. The EP3 antagonist L798106 and EP3 knockdown increased AR expression and cell proliferation, whereas the EP3 agonist sulprostone decreased them, indicating that EP3 affects AR expression. Additionally, EP3 (PTGER3) transcript levels were significantly decreased in human prostate cancer tissues compared with those in normal human prostate tissues, suggesting that EP3 is important to prostate carcinogenesis. Decreased EP3 expression was also seen in castration-resistant subtype CxR cells compared with parental LNCaP cells. Finally, we found that aspirin and EP3 modulators affected prostate cancer cell growth. Taken together, aspirin suppressed LNCaP cell proliferation via EP3 signaling activation; EP3 downregulation contributed to prostate carcinogenesis and to progression from androgen-dependent prostate cancer to castration-resistant prostate cancer by regulating AR expression. In conclusion, cyclooxygenases and EP3 may represent attractive therapeutic molecular targets in androgen-dependent prostate cancer.

Etoricoxib attenuates effect of antihypertensives in a rodent model of DOCA-salt induced hypertension

While it is known that non-steroidal anti-inflammatory drugs including selective cyclooxygenase-2 (COX-2) inhibitors influence BP, the exact relationship and underlying mechanisms are still unclear. We investigated the effect of etoricoxib, a selective COX-2 inhibitor on the antihypertensive efficacy of atenolol; beta-blocker, ramipril; angiotensin converting enzyme inhibitor and telmisartan; angiotensin receptor blocker in deoxycorticosterone acetate (DOCA)-salt hypertensive rats, a mineralocorticoid volume expansion model. Etoricoxib attenuated the antihypertensive-induced reduction of systolic (atenolol; P < .001, ramipril; P = .011, telmisartan; P = .003) and mean arterial pressure (atenolol; P < .001, ramipril; P = .032, telmisartan; P = .023). These results demonstrate that COX-2 dependent mechanisms play a significant role in blood pressure regulation, and etoricoxib-induced COX-2 inhibition blunts the therapeutic effect of different classes of antihypertensives in this mineralocorticoid volume expansion model of hypertension.

The complex interplay between cyclooxygenase-2 and angiotensin II in regulating kidney function

PURPOSE OF REVIEW

Cyclooxygenase-2 (COX-2) plays a critical role in modulating deleterious actions of angiotensin II (Ang II) where there is an inappropriate activation of the renin-angiotensin system (RAS). This review discusses the recent developments regarding the complex interactions by which COX-2 modulates the impact of an activated RAS on kidney function and blood pressure.

RECENT FINDINGS

Normal rats with increased COX-2 activity but with different intrarenal Ang II activity because of sodium restriction or chronic treatment with angiotensin-converting enzyme (ACE) inhibitors showed similar renal hemodynamic responses to COX-2-selective inhibition (nimesulide) indicating independence from the intrarenal Ang II activity. COX-2-dependent maintenance of medullary blood flow was consistent and not dependent on dietary salt or ACE inhibition. In contrast, COX-2 influences on sodium excretion were contingent on the prevailing RAS activity. In chronic hypertensive models, COX-2 inhibition elicited similar reductions in kidney function, but COX-2 metabolites contribute to rather than ameliorate the hypertension.

SUMMARY

The maintenance of renal hemodynamics reflects direct and opposing effects of Ang II and COX-2 metabolites. The antagonism in water and electrolyte reabsorption is dependent on the prevailing intrarenal Ang II activity. The recent functional experiments demonstrate a beneficial modulation of Ang II by COX-2 except in the presence of inflammation promoted by hypertension, hyperglycemia, and oxidative stress.

Regulation of ANP secretion from isolated atria by prostaglandins and cyclooxygenase-2

Cyclooxygenase (COX) is a key enzyme regulating the production of various prostaglandins (PGs) from arachidonic acid. Angiotensin II has been reported to be an important inflammatory mediator, which increases COX-2. The aim of this study was to determine the role of various PGs and COX-2 in the regulation of atrial natriuretic peptide (ANP) secretion. PGF2alpha and PGD2 caused dose-dependent increases in ANP release and intra-atrial pressure. The potency for the stimulation of ANP secretion by PGF2alpha was higher than that by PGD2. In contrast, PGE2, PGI2, PGJ2, and thromboxane A2 did not show any significant effects. The increases in intra-atrial pressure and ANP secretion induced by PGF2alpha and PGD2 were significantly attenuated by the pretreatment with an inhibitor of PGF2alpha receptor. By the pretreatment with an inhibitor for phospholipase C (PLC), inositol 3-phosphate (IP3) receptor, protein kinase C (PKC), or myosin light chain kinase (MLCK), PGF2alpha-mediated increase in ANP secretion and positive inotropy were attenuated. Inhibitor for COX-1 or COX-2 did not cause any significant effects on atrial parameters. In hypertrophied rat atria, PGF2alpha-induced positive inotropy and ANP secretion were markedly attenuated whereas COX-2 inhibitor stimulated ANP secretion. The expression of COX-2 increased and the expression of PGF2alpha receptor mRNA decreased in hypertrophied rat atria. These results suggest that PGF2alpha increased the ANP secretion and positive inotropy through PLC-IP3-PKC-MLCK pathway, and the modulation of ANP secretion by COX-2 inhibitor and PGF2alpha may partly relate to the development of renal hypertension.

Tetradecylthioacetic acid downregulates cyclooxygenase 2 in the renal cortex of two-kidney, one-clip hypertensive rats

The effect of tetradecylthioacetic acid (TTA) on the cyclooxygenase (COX) system was investigated in two-kidney, one-clip (2K1C) hypertensive rats. The systolic blood pressure (BP) was increased 6 wk after clipping to 183 +/- 4 vs.127 +/- 3 mmHg in TTA-treated 2K1C rats. The COX1 protein expression was not affected either by the 2K1C procedure or by TTA treatment. COX2 expression was upregulated in both kidneys, but to a greater extent in the clipped kidney. COX2 activity was 16 +/- 3% in control and 38 +/- 2% (P < 0.001) in the clipped kidney, and COX2 protein expression was 1.3 +/- 0.04 in control and 1.6 +/- 0.12 in the clipped kidney (P = 0.006). TTA reduced COX2 activity to control levels. Subcutaneously infusion of a COX2 inhibitor did not reduce BP. Peroxisome proliferator-activated receptors (PPARs) were detected in both kidneys, and PPARdelta was upregulated in the nonclipped kidney after TTA treatment. PGE2 in renal cortex was increased in 2K1C (31 +/- 0.3 in the clipped and 28 +/- 0.2 pg/ml nonclipped kidney, P < 0.001 compared with control). TTA lowered the PGE2 to control levels. Renal blood flow (RBF) response to exogenous ANG II injected in the control and nonclipped kidney was exaggerated after indomethacin treatment but unchanged in the nonclipped kidney of the K1C TTA group. Overall, these results indicate that, after 6 wk of treatment, TTA downregulated the COX2 activity, which have potentially important effects on the regulation of renal hemodynamics but does not explain TTAs ability to lower BP.

Pulmonary and cardiorenal cyclooxygenase-1 (COX-1), -2 (COX-2), and microsomal prostaglandin E synthase-1 (mPGES-1) and -2 (mPGES-2) expression in a hypertension model

Hypertensive mice that express the human renin and angiotensinogen genes are used as a model for human hypertension because they develop hypertension secondary to increased renin-angiotensin system activity. Our study investigated the cellular localization and distribution of COX-1, COX-2, mPGES-1, and mPGES-2 in organ tissues from a mouse model of human hypertension. Male (n = 15) and female (n = 15) double transgenic mice (h-Ang 204/1 h-Ren 9) were used in the study. Lung, kidney, and heart tissues were obtained from mice at necropsy and fixed in 10% neutral buffered formalin followed by embedding in paraffin wax. Cut sections were stained immunohistochemically with antibodies to COX-1, COX-2, mPGES-1, and mPGES-2 and analyzed by light microscopy. Renal expression of COX-1 was the highest in the distal convoluted tubules, cortical collecting ducts, and medullary collecting ducts; while proximal convoluted tubules lacked COX-1 expression. Bronchial and bronchiolar epithelial cells, alveolar macrophages, and cardiac vascular endothelial cells also had strong COX-1 expression, with other renal, pulmonary, or cardiac microanatomic locations having mild-to-moderate expression. mPGES-2 expression was strong in the bronchial and bronchiolar epithelial cells, mild to moderate in various renal microanatomic locations, and absent in cardiac tissues. COX-2 expression was strong in the proximal and distal convoluted tubules, alveolar macrophages, and bronchial and bronchiolar epithelial cells. Marked mPGES-1 was present only in bronchial and bronchiolar epithelial cells; while mild-to-moderate expression was present in other pulmonary, renal, or cardiac microanatomic locations. Expression of these molecules was similar between males and females. Our work suggests that in hypertensive mice, there are (a) significant microanatomic variations in the pulmonary, renal, and cardiac distribution and cellular localization of COX-1, COX-2, mPGES-1, and mPGES-2, and (b) no differences in expression between genders.

Roles of vasoconstrictor prostaglandins, COX-1 and -2, and AT1, AT2, and TP receptors in a rat model of early 2K,1C hypertension

Angiotensin (ANG) II activating type 1 receptors (AT1Rs) enhances superoxide anion (O2•−) and arachidonate (AA) formation. AA is metabolized by cyclooxygenases (COXs) to PGH2, which is metabolized by thromboxane (Tx)A2synthase to TxA2or oxidized to 8-isoprostane PGF2α(8-Iso) by O2•−. PGH2, TxA2, and 8-Iso activate thromboxane-prostanoid receptors (TPRs). We investigated whether blood pressure in a rat model of early (3 wk) two-kidney, one-clip (2K,1C) Goldblatt hypertension is maintained by AT1Rs or AT2Rs, driving COX-1 or -2-dependent products that activate TPRs. Compared with sham-operated rats, 2K,1C Goldblatt rats had increased mean arterial pressure (MAP; 120 ± 4 vs. 155 ± 3 mmHg; P < 0.001), plasma renin activity (PRA; 22 ± 7 vs. 48 ± 5 ng·ml−1·h−1; P < 0.01), plasma malondialdehyde (1.07 ± 0.05 vs. 1.58 ± 0.16 nmol/l; P < 0.01), and TxB2excretion (26 ± 4 vs. 51 ± 7 ng/24 h; P < 0.01). Acute graded intravenous doses of benazeprilat (angiotensin-converting enzyme inhibitor) reduced MAP at 20 min (−36 ± 5 mmHg; P < 0.001) and excretion of TxA2metabolites. Indomethacin (nonselective COX antagonist) or SC-560 (COX-1 antagonist) reduced MAP at 20 min (−25 ± 5 and −28 ± 7 mmHg; P < 0.001), whereas valdecoxib (COX-2 antagonist) was ineffective (−9 ± 5 mmHg; not significant). Losartan (AT1R antagonist) or SQ-29548 (TPR antagonist) reduced MAP at 150 min (−24 ± 6 and −22 ± 3 mmHg; P < 0.001), whereas PD-123319 (AT2R antagonist) was ineffective. Acute blockade of TPRs, COX-1, or COX-2 did not change PRA, but TxB2generation by the clipped kidney was reduced by blockade of COX-1 and increased by blockade of COX-2. 2K,1C hypertension in rats activates renin, O2•−, and vasoconstrictor PGs. Hypertension is maintained by AT1Rs and by COX-1, but not COX-2, products that activate TPRs.

Fasudil Attenuates Myocardial Fibrosis in Association With Inhibition of Monocyte/Macrophage Infiltration in the Heart of DOCA/Salt Hypertensive Rats

OBJECTIVE

To determine the effects of fasudil, a Rho-kinase inhibitor, on mineralocorticoid-induced myocardial remodeling, we investigated whether fasudil would suppress myocardial fibrosis and inflammation in deoxycorticosterone-acetate (DOCA)/salt hypertensive rats.

METHODS

Sprague-Dawley rats treated with DOCA combined with 1% NaCl and 0.2% KCl in the drinking water after receiving left nephrectomy were given fasudil (10 mg/kg/day; n = 20) or vehicle (n = 20). Systolic blood pressure (SBP) was measured biweekly. Myocardial monocyte/macrophage infiltration and myocardial fibrosis were determined histologically. Expressions of mRNA of procollagen I (PI), procollagen III (PIII), monocyte chemoattractant protein (MCP)-1, interleukin (IL)-6, type-1 plasminogen activator inhibitor (PAI-1), transforming growth factor (TGF)-beta1, and c-fos were determined.

RESULTS

SBP was significantly increased on day 14 after treatment with DOCA/salt. Extent of interstitial and perivascular fibrosis was significantly increased on day 28. Expressions of mRNA of PI, PIII, MCP-1, IL-6, PAI-1, TGF-beta1, and c-fos were significantly increased on day 14. Although SBP did not differ between the fasudil and vehicle groups, extent of monocyte/macrophage infiltration and fibrosis was attenuated in the fasudil group. Expressions of mRNA of these factors except TGF-beta1 were also attenuated.

CONCLUSION

Fasudil attenuates myocardial fibrosis possibly via suppression of monocyte/macrophage infiltration of the heart in DOCA/salt hypertensive rats.

Comparison of the effects of valsartan and felodipine on plasma leptin and insulin sensitivity in hypertensive obese patients

Aim of this study was to compare the effect of valsartan and felodipine on blood pressure (BP), plasma leptin (L), insulin sensitivity and plasma norepinephrine (NE) in obese hypertensive patients. Ninty-six obese patients (body mass index [BMI] > or = 30 kg/m2) with mild to moderate essential hypertension (diastolic blood pressure [DBP] > 90 and < 110 mmHg, as evaluated with an appropriately sized cuff) aged 31-60 years, were randomized to a valsartan (80 mg/day for 16 weeks; n = 48) or felodipine (5 mg/day for 16 weeks; n = 48) treatment group after a 2-week wash-out period. After the first 4 weeks of treatment there was a titration with dose-doubling in non responder patients (DBP > 90 mmHg). At the end of the placebo period and of active treatment period, BP and BMI were evaluated and a venous sample was drawn at the same hour in the morning to evaluate plasma L and NE. Insulin resistance index (HOMA-IR) was calculated. No dietary advice was prescribed. Both valsartan and felodipine significantly decreased BP values (-19.3/15 mmHg and -18.9/13.6 mmHg, respectively p < 0.001 vs. placebo), with no difference between treatments. However, felodipine increased plasma NE (+124 pg/ml, +38.2%, p < 0.05 vs. placebo and < 0.01 vs. valsartan) and had no effect on L, body weight and HOMA-IR index, while valsartan did not modify NE and produced a significant reduction in L (-3.7 ng/ml, -10.1%, p < 0.05 vs. placebo), BMI (-1.7 kg/m2, -4.7%, p < 0.01 vs. placebo) and HOMA-IR index (-1.6, -20%, p < 0.05 vs. placebo). These results suggest that in hypertensive obese subjects, treatment with valsartan might offer an advantage over treatment with felodipine, since valsartan may help to improve obesity-related disorders in addition to lowering BP.

Androgens are necessary for the development of fructose-induced hypertension

Hyperinsulinemia and insulin resistance are closely associated with hypertension in humans and in animal models. Gender differences have been found in the development of hypertension in fructose-fed rats. The objectives of the present study were, first, to clarify whether androgens are required in the development of hyperinsulinemia, insulin resistance, and hypertension in fructose-fed rats, and second, to determine if cyclooxygenase-1 and cyclooxygenase-2 are also increased in the arteries of these rats. Male rats were gonadectomized or sham-operated and fed a 60% fructose diet beginning at age 7 weeks. Blood pressure was measured by a tail-cuff method, and an oral glucose tolerance test was performed to assess insulin sensitivity after 8 weeks of fructose feeding. Cyclooxygenase-1 and cyclooxygenase-2 mRNA expression was also assessed in the thoracic aortae and mesenteric arteries. Gonadectomy prevented hypertension from developing in the fructose-fed rats, but hyperinsulinemia and insulin resistance developed. There was an increase in cyclooxygenase-2 expression in the thoracic aortae and mesenteric arteries of the fructose-fed sham-operated rats while the expression of cyclooxygenase-1 remained unchanged. Gonadectomy prevented the mRNA overexpression of vascular cyclooxygenase-2 in the fructose-fed rats. These results suggest that the presence of androgens is necessary for the development of fructose-induced hypertension. Androgens apparently act as a link between hyperinsulinemia/insulin resistance and hypertension in fructose-hypertensive rats. Furthermore, an increase in the expression of cyclooxygenase-2 is implicated in the development of hypertension. The mechanisms involved require further study.