Protective role of the mitochondrial fusion protein OPA1 in hypertension.

Hypertension is associated with excessive reactive oxygen species (ROS) production in vascular cells. Mitochondria undergo fusion and fission, a process playing a role in mitochondrial function. OPA1 is essential for mitochondrial fusion. Loss of OPA1 is associated with ROS production and cell dysfunction. We hypothesized that mitochondria fusion could reduce oxidative stress that defect in fusion would exacerbate hypertension. Using (a) Opa1 haploinsufficiency in isolated resistance arteries from Opa1+/- mice, (b) primary vascular cells from Opa1+/- mice, and (c) RNA interference experiments with siRNA against Opa1 in vascular cells, we investigated the role of mitochondria fusion in hypertension. In hypertension, Opa1 haploinsufficiency induced altered mitochondrial cristae structure both in vascular smooth muscle and endothelial cells but did not modify protein level of long and short forms of OPA1. In addition, we demonstrated an increase of mitochondrial ROS production, associated with a decrease of superoxide dismutase 1 protein expression. We also observed an increase of apoptosis in vascular cells and a decreased VSMCs proliferation. Blood pressure, vascular contractility, as well as endothelium-dependent and -independent relaxation were similar in Opa1+/- , WT, L-NAME-treated Opa1+/- and WT mice. Nevertheless, chronic NO-synthase inhibition with L-NAME induced a greater hypertension in Opa1+/- than in WT mice without compensatory arterial wall hypertrophy. This was associated with a stronger reduction in endothelium-dependent relaxation due to excessive ROS production. Our results highlight the protective role of mitochondria fusion in the vasculature during hypertension by limiting mitochondria ROS production.

Knockout of γ-Adducin Promotes NG-Nitro-L-Arginine-Methyl-Ester-Induced Hypertensive Renal Injury.

Previous studies identified a region on chromosome 1 associated with NG-nitro-L-arginine methyl ester (L-NAME) hypertension-induced renal disease in fawn-hooded hypertensive (FHH) rats. This region contains a mutant γ-adducin (Add3) gene that impairs renal blood flow (RBF) autoregulation, but its contribution to renal injury is unknown. The present study evaluated the hypothesis that knockout (KO) of Add3 impairs the renal vasoconstrictor response to the blockade of nitric oxide synthase and enhances hypertension-induced renal injury after chronic administration of L-NAME plus a high-salt diet. The acute hemodynamic effect of L-NAME and its chronic effects on hypertension and renal injury were compared in FHH 1Brown Norway (FHH 1BN) congenic rats (WT) expressing wild-type Add3 gene versus FHH 1BN Add3 KO rats. RBF was well autoregulated in WT rats but impaired in Add3 KO rats. Acute administration of L-NAME (10 mg/kg) raised mean arterial pressure (MAP) similarly in both strains, but RBF and glomerular filtration rate (GFR) fell by 38% in WT versus 15% in Add3 KO rats. MAP increased similarly in both strains after chronic administration of L-NAME and a high-salt diet; however, proteinuria and renal injury were greater in Add3 KO rats than in WT rats. Surprisingly, RBF, GFR, and glomerular capillary pressure were 41%, 82%, and 13% higher in L-NAME-treated Add3 KO rats than in WT rats. Hypertensive Add3 KO rats exhibited greater loss of podocytes and glomerular nephrin expression and increased interstitial fibrosis than in WT rats. These findings indicate that loss of ADD3 promotes L-NAME-induced renal injury by altering renal hemodynamics and enhancing the transmission of pressure to glomeruli. SIGNIFICANCE STATEMENT: A mutation in the γ-adducin (Add3) gene in fawn-hooded hypertensive rats that impairs autoregulation of renal blood flow is in a region of rat chromosome 1 homologous to a locus on human chromosome 10 associated with diabetic nephropathy. The present results indicate that loss of ADD3 enhanced NG-nitro-L-arginine methyl ester-induced hypertensive renal injury by altering the transmission of pressure to the glomerulus.

NADPH oxidase-induced oxidative stress in the eyes of hypertensive rats.

Purpose: Increased reactive oxygen species (ROS) released by NADPH oxidase and inflammation are associated with arterial hypertension and eye diseases associated with high blood pressure, including glaucoma, retinopathies (e.g., age-related macular degeneration), and choroidopathies affecting ocular function; however, the mechanisms underlying these adverse outcomes remain undefined. The present study was designed to highlight the importance of oxidative stress in severe hypertension-related eye damage. Methods: Male Wistar rats (n = 7, unless otherwise specified for specific experiments) were administered an oral dose of 30 mg of Nω-nitro-L-arginine methyl ester (L-NAME) per kilogram of bodyweight and day for 3 weeks; chronic administration with L-NAME is a validated experimental approach resulting in severe hypertension secondary to nitric oxide (NO) depletion and subsequent vasoconstriction in the systemic circulation. Upon treatment completion, histomorphometric studies, NADPH oxidase activity, and ROS production were measured in eyecup homogenates and paraffin-embedded sections from control and L-NAME-treated animals. In addition, immunohistofluorescence, western blotting, and real-time PCR (RT-qPCR) analyses were performed in the eye and the retina to evaluate the expression of i) NADPH oxidase main isoforms (NOX1, NOX2, and NOX4) and subunits (p22phox and p47phox); ii) glial fibrillary acidic protein (GFAP), as a marker of microglial activation in the retina; iii) antioxidant enzymes; and iv) endothelial constitutive (eNOS) and inflammation inducible (iNOS) nitric oxide synthase isoforms, and nitrotyrosine as a versatile biomarker of oxidative stress. Results: Increased activity of NADPH oxidase and superoxide anion production, accompanied by transcriptional upregulation of this enzyme isoforms, was found in the retina and choroid of the hypertensive rats in comparison with the untreated controls. Histomorphometric analyses revealed a significant reduction in the thickness of the ganglion cell layer and the outer retinal layers in the hypertensive animals, which also showed a positive strong signal of GFAP in the retinal outer segment and plexiform layers. In addition, L-NAME-treated animals presented with upregulation of nitric oxide synthase (including inducible and endothelial isoforms) and abnormally elevated nitrotyrosine levels. Experiments on protein and mRNA expression of antioxidant enzymes revealed depletion of superoxide dismutase and glutathione peroxidase in the eyes of the hypertensive animals; however, glutathione reductase was significantly higher than in the normotensive controls. Conclusions: The present study demonstrated structural changes in the retinas of the L-NAME-treated hypertensive animals and strengthens the importance of NADPH oxidase as a major ROS-generating enzyme system in the oxidative and inflammatory processes surrounding hypertensive eye diseases. These observations might contribute to unveiling pathogenic mechanisms responsible for developing ocular disturbances in the context of severe hypertension.

Aqueous extract of oakmoss produces antihypertensive activity in L-NAME-induced hypertensive rats through sGC-cGMP pathway.

BACKGROUND: Lichens are a symbiotic association of a fungus with a green alga or cyanobacterium. They are widely used in traditional medicine as a treatment against skin disorders, diabetes and hypertension. THE AIM OF THE STUDY: The goal of this paper was to assess the possible antihypertensive and vasorelaxant capacity of the aqueous extract of a lichen species called Oakmoss or Evernia prunastri (L.). MATERIAL AND METHODS: In the present study, the aqueous extract of Oakmoss was prepared, its antihypertensive activity was examined in N(ω)-nitro-L-arginine methyl ester (L-NAME)-induced hypertensive rats, and its vasorelaxant ability was performed in rat isolated thoracic aorta. RESULTS: The results proved that Oakmoss reduced the systolic, diastolic, mean arterial blood pressure, and heart rate in hypertensive rats but not in normotensive rats. Besides, the data showed that Oakmoss exerts its antihypertensive effect through vasorelaxant ability. CONCLUSION: The present study presents the favorable action of Oakmoss as an antihypertensive agent.

L-NAME Administration Enhances Diabetic Kidney Disease Development in an STZ/NAD Rat Model.

One of the most important risk factors for developing chronic kidney disease (CKD) is diabetes. To assess the safety and efficacy of potential drug candidates, reliable animal models that mimic human diseases are crucial. However, a suitable model of diabetic kidney disease (DKD) is currently not available. The aim of this study is to develop a rat model of DKD by combining streptozotocin and nicotinamide (STZ/NAD) with oral N(ω)-Nitro-L-Arginine Methyl Ester (L-NAME) administration. Diabetes was induced in male Wistar rats by intravenous injection of 65 mg/kg STZ, 15 min after intraperitoneal injection of 230 mg/kg NAD. Rats were assigned to different groups receiving L-NAME (100 mg/kg/day) (STZ/NAD/L-NAME) or vehicle (STZ/NAD) for a period of 9 or 12 weeks by daily oral gavage. All rats developed hyperglycemia. Hyperfiltration was observed at the start of the study, whereas increased serum creatinine, albumin-to-creatinine ratio, and evolving hypofiltration were detected at the end of the study. Daily L-NAME administration caused a rapid rise in blood pressure. Histopathological evaluation revealed heterogeneous renal injury patterns, which were most severe in the STZ/NAD/L-NAME rats. L-NAME-induced NO-deficiency in STZ/NAD-induced diabetic rats leads to multiple characteristic features of human DKD and may represent a novel rat model of DKD.

Enhancing Renal Lymphatic Expansion Prevents Hypertension in Mice.

RATIONALE: Hypertension is associated with renal infiltration of activated immune cells; however, the role of renal lymphatics and immune cell exfiltration is unknown. OBJECTIVE: We tested the hypotheses that increased renal lymphatic density is associated with 2 different forms of hypertension in mice and that further augmenting renal lymphatic vessel expansion prevents hypertension by reducing renal immune cell accumulation. METHODS AND RESULTS: Mice with salt-sensitive hypertension or nitric oxide synthase inhibition-induced hypertension exhibited significant increases in renal lymphatic vessel density and immune cell infiltration associated with inflammation. Genetic induction of enhanced lymphangiogenesis only in the kidney, however, reduced renal immune cell accumulation and prevented hypertension. CONCLUSIONS: These data demonstrate that renal lymphatics play a key role in immune cell trafficking in the kidney and blood pressure regulation in hypertension.

Effects of hydrogen sulphide donor, sodium hydrosulphide treatment on the erectile dysfunction in L-NAME-induced hypertensive rats.

Men with hypertension often develop erectile dysfunction (ED). The present study aimed to examine the effects of sodium hydrosulphide (NaHS), a hydrogen (H2 S) donor, treatment on ED in nitric oxide synthase (NOS) inhibitor (L-NAME)-induced hypertensive rats. Forty adult Sprague-Dawley rats were divided into four groups: control, NaHS (0.037 mg kg day-1 )-treated control, L-NAME-induced hypertension (40 mg kg day-1 ) and NaHS-treated L-NAME-induced hypertension. The ratio of intracavernosal pressure to mean arterial pressure and isometric tension of corpus cavernosum (CC) were measured. The penile expression of endothelial and neuronal NOS (eNOS and nNOS), inflammation markers [nuclear factor kappa B (NF-κB) and inhibitor kappa B alpha (IκBα)], H2 S-producing enzymes[cystathionine ß-synthase (CBS) and cystathionine γ-lyase (CSE)], the smooth muscle/collagen ratio and H2 S concentrations were determined. The blood pressure was significantly increased in the hypertensive group, but not reversed by NaHS. The erectile response in hypertensive rats was partially prevented by NaHS. The relaxation response to electrical field stimulation was increased in CC from NaHS-treated hypertensive rats. NaHS treatment restored decreased protein expression of eNOS, nNOS and CSE as well as smooth muscle/collagen ratio and H2 S levels and increased NF-κB and IκBα protein expression in the penile tissue of hypertensive rats. NaHS promoted the recovery of erectile responses in hypertensive rats by improvement of neuronal function and downregulation of fibrosis and NF-κB signalling.

CD70 Exacerbates Blood Pressure Elevation and Renal Damage in Response to Repeated Hypertensive Stimuli.

RATIONALE: Accumulating evidence supports a role of adaptive immunity and particularly T cells in the pathogenesis of hypertension. Formation of memory T cells, which requires the costimulatory molecule CD70 on antigen-presenting cells, is a cardinal feature of adaptive immunity. OBJECTIVE: To test the hypothesis that CD70 and immunologic memory contribute to the blood pressure elevation and renal dysfunction mediated by repeated hypertensive challenges. METHODS AND RESULTS: We imposed repeated hypertensive challenges using either N(ω)-nitro-L-arginine methyl ester hydrochloride (L-NAME)/high salt or repeated angiotensin II stimulation in mice. During these challenges effector memory T cells (T(EM)) accumulated in the kidney and bone marrow. In the L-NAME/high-salt model, memory T cells of the kidney were predominant sources of interferon-γ and interleukin-17A, known to contribute to hypertension. L-NAME/high salt increased macrophage and dendritic cell surface expression of CD70 by 3- to 5-fold. Mice lacking CD70 did not accumulate T(EM) cells and did not develop hypertension to either high salt or the second angiotensin II challenge and were protected against renal damage. Bone marrow-residing T(EM) cells proliferated and redistributed to the kidney in response to repeated salt feeding. Adoptively transferred T(EM) cells from hypertensive mice homed to the bone marrow and spleen and expanded on salt feeding of the recipient mice. CONCLUSIONS: Our findings illustrate a previously undefined role of CD70 and long-lived T(EM) cells in the development of blood pressure elevation and end-organ damage that occur on delayed exposure to mild hypertensive stimuli. Interventions to prevent repeated hypertensive surges could attenuate formation of hypertension-specific T(EM) cells.

Aliskiren and valsartan in combination is a promising therapy for hypertensive renal injury in rats.

Neither ACEI nor ARBs completely repress the RAAS. Aliskiren is a newer agent that inhibits renin. However, it increases the biosynthesis and secretion of renin and prorenin, that might induce renal tissue damage. This study was conducted to investigate the renoprotective effects of aliskiren and valsartan the ARB, either alone or in combination, on hypertensive nephropathy induced by L-NAME. Aliskiren (50 mg/kg/daily i.p.), valsartan (10 mg/kg daily i.p.) alone or in half dose combination were administered with L-NAME (30-40 mg daily in drinking water) for 8 weeks. Aliskiren and valsartan significantly reduced systolic blood pressure, proteinuria, serum creatinine, blood urea nitrogen, oxidative stress, and structural renal injury although not to the same extent. Valsartan reduced systolic blood pressure and proteinuria in L-NAME treated rats more significantly than aliskiren. However, glomerular collapse index and the expansion of interstitial tissue were significantly attenuated by aliskiren than by valsartan. Cotreatment with aliskiren and valsartan markedly reduced the oxidative stress and further reduced the glomerular collapse and the expansion of interstitial tissue compared with aliskiren monotherapy. CONCLUSION: These results suggest that therapies aimed at different targets within the RAAS may have additional effects in attenuating structural injury in experimental hypertensive nephropathy.

In vitro renin-angiotensin system inhibition and in vivo antihypertensive activity of peptide fractions from lima bean (Phaseolus lunatus L.).

BACKGROUND: The renin-angiotensin system is key in the physiopathology of arterial hypertension because it converts angiotensin I, via angiotensin I-converting enzyme (ACE), into angiotensin II. In vitro analyses were done of the ACE-inhibitory and renin-inhibitory activities of peptide fractions isolated by enzymatic hydrolysis of lima bean (Phaseolus lunatus) protein. Antihypertensive activity was confirmed in vivo using a rat model. RESULTS: Lima bean protein was hydrolyzed with one of two sequential enzymatic systems (pepsin-pancreatin or Alcalase®-Flavourzyme®). Ultrafiltration of the hydrolysates produced fractions of different molecular weights. The >3 kDa fraction of the pepsin-pancreatin hydrolysate had the highest ACE-inhibitory activity (60.15%, IC50: 172.62 µg mL-1 ), while the >3 KDa fraction of the Alcalase®-Flavourzyme® hydrolysate had the highest in vitro renin-inhibitory activity. A weak correlation (r = 0.44) was found between ACE-inhibitory and renin-inhibitory activities. When tested in vivo, the latter fraction lowered systolic blood pressure by 64% and diastolic blood pressure by 51%. CONCLUSION: Peptide fractions from lima bean Phaseolus lunatus protein hydrolysates exhibit both in vitro and in vivo antihypertensive activity. Bioactive peptides from lima bean have potential applications as ingredients in functional foods. © 2017 Society of Chemical Industry.

[ASSESSMENT OF SPECIFIC PHARMACOLOGIC ACTIVITY OF UNIFUSOL ON ENDOTHELIUM DYSFUNCTION MODEL INDUCED BY N-NITRO-L-ARGININE METHYL ETHER.]

Specific pharmacologic activity of sodium-L-arginine succinate (unifusol) was studied on endothelium dysfunction model (EDM) in rats. EDM was induced by daily administration of N-nitro-L-arginine methyl ether (L-NAME). The effectiveness of experimental therapy with unifusol was assessed by changes in the arterial pressure level, duration of endothelium-dependent and -independent vasodilation, and the blood concentration of endothelial dysfunction markers including VEGF, NO, endothelin-I and the number of desquamated endotheliocytes. Administration of unifusol favors correction of blood vessel endothelium state manifested by normalization of its functional activity and reduction of the apoptosis of endotheliocytes. In addition, the obtained results unambiguously confirm considerable vasodilating and antihypertensive effects of unifusol.

Chronic NOS inhibition accelerates NAFLD progression in an obese rat model.

The progression in nonalcoholic fatty liver disease (NAFLD) to nonalcoholic steatohepatitis is a serious health concern, but the underlying mechanisms remain unclear. We hypothesized that chronic inhibition of nitric oxide (NO) synthase (NOS) via N(ω)-nitro-L-arginine methyl ester (L-NAME) would intensify liver injury in a rat model of obesity, insulin resistance, and NAFLD. Obese Otsuka Long-Evans Tokushima fatty (OLETF) and lean Long-Evans Tokushima Otsuka (LETO) rats received control or L-NAME (65-70 mg·kg(-1)·day(-1))-containing drinking water for 4 wk. L-NAME treatment significantly (P < 0.05) reduced serum NO metabolites and food intake in both groups. Remarkably, despite no increase in body weight, L-NAME treatment increased hepatic triacylglycerol content (+40%, P < 0.05) vs. control OLETF rats. This increase was associated with impaired (P < 0.05) hepatic mitochondrial state 3 respiration. Interestingly, the opposite effect was found in LETO rats, where L-NAME increased (P < 0.05) hepatic mitochondrial state 3 respiration. In addition, L-NAME induced a shift toward proinflammatory M1 macrophage polarity, as indicated by elevated hepatic CD11c (P < 0.05) and IL-1ß (P = 0.07) mRNA in OLETF rats and reduced expression of the anti-inflammatory M2 markers CD163 and CD206 (P < 0.05) in LETO rats. Markers of total macrophage content (CD68 and F4/80) mRNA were unaffected by L-NAME in either group. In conclusion, systemic NOS inhibition in the obese OLETF rats reduced hepatic mitochondrial respiration, increased hepatic triacylglycerol accumulation, and increased hepatic inflammation. These findings suggest an important role for proper NO metabolism in the hepatic adaptation to obesity.

Serotonin depletion can enhance the cerebrovascular responses induced by cortical spreading depression via the nitric oxide pathway.

Serotonin (5-HT) is an important neurotransmitter involved in the control of neural and vascular responses. 5-HT depletion can induce several neurological disorders, including migraines. Studies on a cortical spreading depression (CSD) migraine animal model showed that the cortical neurons sensitivity, vascular responses, and nitric oxide (NO) production were significantly increased in 5-HT depletion. However, the involvement of NO in the cerebrovascular responses in 5-HT depletion remains unclear. This study aimed to investigate the role of NO in the CSD-induced alterations of cerebral microvessels in 5-HT depletion. Rats were divided into four groups: control, control with L-NAME treatment, 5-HT depleted, and 5-HT depleted with L-NAME treatment. 5-HT depletion was induced by intraperitoneal injection with para-chlorophenylalanine (PCPA) 3 days before the experiment. The CSD was triggered by KCl application. After the second wave of CSD, N-nitro-l-arginine methyl ester (L-NAME) or saline was intravenously injected into the rats with or without L-NAME treatment groups, respectively. The intercellular adhesion molecules-1 (ICAM-1), cell adhesion molecules-1 (VCAM-1), and the ultrastructural changes of the cerebral microvessels were examined. The results showed that 5-HT depletion significantly increased ICAM-1 and VCAM-1 expressions in the cerebral cortex. The number of endothelial pinocytic vesicles and microvilli was higher in the 5-HT depleted group when compared to the control. Interestingly, L-NAME treatment significantly reduced the abnormalities observed in the 5-HT depleted group. The results of this study demonstrated that an increase of NO production is one of the mechanisms involved in the CSD-induced alterations of the cerebrovascular responses in 5-HT depletion.

Parecoxib Increases Blood Pressure Through Inhibition of Cyclooxygenase-2 Messenger RNA in an Experimental Model.

BACKGROUND: Cyclooxygenase-2 selective inhibitors have been developed to alleviate pain and inflammation; however, the use of a selective cyclooxygenase-2 inhibitor is associated with mild edema, hypertension, and cardiovascular risk. AIM: To evaluate, in an experimental model in normotensive rats, the effect of treatment with parecoxib in comparison with diclofenac and aspirin and L-NAME, a non-selective nitric oxide synthetase, on mean arterial blood pressure, and cyclooxygenase-1 and -2 messenger RNA and protein expression in aortic tissue. METHODS: Rats were treated for seven days with parecoxib (10 mg/kg/day), diclofenac (3.2 mg/kg/day), aspirin (10 mg/kg/day), or L-NAME (10 mg/kg/day). Mean arterial blood pressure was evaluated in rat tail; cyclooxygenase-1 and -2 were evaluated by reverse transcription-polymerase chain reaction and Western blot analysis in aortic tissue. RESULTS: Parecoxib and L-NAME, but not aspirin and diclofenac, increased mean arterial blood pressure by about 50% (p < 0.05) without changes in cardiac frequency. Messenger RNA cyclooxygenase-1 expression in aortic tissue was not modified with any drug (p < 0.05). L-NAME and parecoxib treatment decreased messenger RNA cyclooxygenase-2 and cyclooxygenase-2 (p < 0.05). While cyclooxygenase-1 protein decreased with the three drugs tested but not with L-NAME (p < 0.05), the cyclooxygenase-2 protein decreased only with aspirin and parecoxib (p < 0.05). CONCLUSION: Parecoxib increases the blood pressure of normotensive rats by the suppression of COX-2 gene expression, which apparently induced cardiovascular control.

Quantification of cardiomyocyte hypertrophy by cardiac magnetic resonance: implications for early cardiac remodeling.

BACKGROUND: Cardiomyocyte hypertrophy is a critical precursor to the development of heart failure. Methods to phenotype cellular hypertrophy noninvasively are limited. The goal was to validate a cardiac magnetic resonance-based approach for the combined assessment of extracellular matrix expansion and cardiomyocyte hypertrophy. METHODS AND RESULTS: Two murine models of hypertension (n=18, with n=15 controls) induced by l-N(G)-nitroarginine methyl ester (L-NAME) and pressure overload (n=11) from transaortic constriction (TAC) were imaged by cardiac magnetic resonance at baseline and 7 weeks after L-NAME treatment or up to 7 weeks after TAC. T1 relaxation times were measured before and after gadolinium contrast. The intracellular lifetime of water (τic), a cell size-dependent parameter, and extracellular volume fraction, a marker of interstitial fibrosis, were determined with a model for transcytolemmal water exchange. Cardiomyocyte diameter and length were measured on FITC-wheat germ agglutinin-stained sections. The τic correlated strongly with histological cardiomyocyte volume-to-surface ratio (r=0.78, P<0.001) and cell volume (r=0.75, P<0.001). Histological cardiomyocyte diameters and cell volumes were higher in mice treated with L-NAME compared with controls (P<0.001). In the TAC model, cardiac magnetic resonance and histology showed cell hypertrophy at 2 weeks after TAC without significant fibrosis at this early time point. Mice exposed to TAC demonstrated a significant, longitudinal, and parallel increase in histological cell volume, volume-to-surface ratio, and τic between 2 and 7 weeks after TAC. CONCLUSION: The τic measured by contrast-enhanced cardiac magnetic resonance provides a noninvasive measure of cardiomyocyte hypertrophy. Extracellular volume fraction and τic can track myocardial tissue remodeling from pressure overload.

Role of macrophage PPARγ in experimental hypertension.

Targeted disruption of the Alox15 gene makes mice resistant to angiotensin II-, DOCA/salt-, and N(ω)-nitro-L-arginine methyl ester (L-NAME)-induced experimental hypertension. Macrophages, a primary source of Alox15, are facilitating this resistance, but the underlying mechanism is not known. Because Alox15 metabolites are peroxisome proliferator-activated receptor (PPAR)γ agonists, we hypothesized that activation of macrophage PPARγ is the key step in Alox15 mediation of hypertension. Thioglycollate, used for macrophage elicitation, selectively upregulated PPARγ and its target gene CD36 in peritoneal macrophages of both wild-type (WT) and Alox15(-/-) mice. Moreover, thioglycollate-injected Alox15(-/-) mice became hypertensive upon L-NAME treatment. A similar hypertensive effect was observed with adoptive transfer of thioglycollate-elicited Alox15(-/-) macrophages into Alox15(-/-) recipient mice. The role of PPARγ was further specified by using the selective PPARγ antagonist GW9662. WT mice treated with 50 µg/kg daily dose of GW9662 for 12 days became resistant to L-NAME-induced hypertension. The PPARγ antagonist treatment also prevented L-NAME-induced hypertension in thioglycollate-injected Alox15(-/-) mice, indicating a PPARγ-mediated effect in macrophage elicitation and the resultant hypertension. These results indicate a regulatory role for macrophage-localized PPARγ in L-NAME-induced experimental hypertension.

Role of propolis on biochemical parameters in kidney and heart tissues against L-NAME induced oxidative injury in rats.

Nitric oxide (NO), produced by endothelial NO synthase, is recognised as a central antiinflammatory and antiatherogenic principle in the vasculature. Epidemiological and clinical studies have demonstrated that a growing list of natural products, as components of the daily diet or phytomedical preparations, may improve vascular function by enhancing NO bioavailability. In this article, we investigated antioxidant effects of propolis on biochemical parameters in kidney and heart tissues of acute NO synthase inhibited rats by Nω-nitro-l-arginine methyl ester (l-NAME). There was increase (p < 0.001) in the activities of catalase and malondialdehyde levels in the l-NAME treatment groups when compared with control rats, but NO levels were decreased in both kidney and heart tissues. There were statistically significant changes (p < 0.001) in these parameters of l-NAME + propolis treated rats as compared with l-NAME-treated group. In summary, propolis may influence endothelial NO production.

Long-term effects of maternal citrulline supplementation on renal transcriptome prevention of nitric oxide depletion-related programmed hypertension: the impact of gene-nutrient interactions.

Maternal malnutrition can elicit gene expression leading to fetal programming. L-citrulline (CIT) can be converted to L-arginine to generate nitric oxide (NO). We examined whether maternal CIT supplementation can prevent N(G)-nitro-L-arginine-methyl ester (L-NAME, NO synthase inhibitor)-induced programmed hypertension and examined their effects on the renal transcriptome in male offspring using next generation RNA sequencing (RNA-Seq) technology. Pregnant Sprague-Dawley rats received L-NAME administration at 60mg/kg/day subcutaneously via osmotic minipump during pregnancy alone or with additional 0.25% L-citrulline solution in drinking water during the whole period of pregnancy and lactation. Male offspring were assigned to three groups: control, L-NAME, and L-NAME + CIT. L-NAME exposure induced hypertension in the 12-week-old offspring, which CIT therapy prevented. Identified differentially expressed genes in L-NAME and CIT-treated offspring kidneys, including Guca2b, Hmox1, Hba2, Hba-a2, Dusp1, and Serpine1 are related to regulation of blood pressure (BP) and oxidative stress. In conclusion, our data suggests that the beneficial effects of CIT supplementation are attributed to alterations in expression levels of genes related to BP control and oxidative stress. Our results suggest that early nutritional intervention by CIT has long-term impact on the renal transcriptome to prevent NO depletion-related programmed hypertension. However, our RNA-Seq results might be a secondary phenomenon. The implications of epigenetic regulation at an early stage of programming deserve further clarification.

Individual and concomitant effects of cardioprotective programs on cardiac apelinergic system and oxidative state in L-NAME-induced hypertension.

The effect of aerobic training and Ferula gummosa supplementation (90 mg/kg) on apelinergic system and markers of cardiac stress in hypertensive rats were studied. Chronically administered l-NAME resulted in an increased level of angiotensin-converting enzyme (ACE), malondialdehyde (MDA), and high-sensitive C-reactive protein (hs-CRP), and also reduced the levels of apelin, apelin and its receptor (APJ), and nitric oxide (NO) and the total antioxidant capacity (TAC), when compared with the control group. The combination of aerobic exercise and Ferula gummosa decreased MDA and hs-CRP and significantly increased cardiac apelinergic system, NO, and TAC, when compared with the control and the l-NAME groups. A rationale for an inhibitory role and a cardioprotective effect of aerobic exercise training in the attenuation of hypertension-induced cardiotoxicity was developed.

Effects of lisinopril on NMDA receptor subunits 2A and 2B levels in the hippocampus of rats with L-NAME-induced hypertension.

Hypertension is major risk factor leading to cerebrovascular pathologies. N-methyl D-aspartate receptors (NMDARs) and renin-angiotensin system are involved in neuronal plasticity, as well as cognitive functions in the hippocampus. In this study, we examined the effects of lisinopril, an ACE inhibitor, on the levels of hippocampal NMDAR subunits; NR2A and NR2B in L-NAME (N(ε)-nitro-L-arginine Methyl Ester)-induced hypertensive rats. In addition, malondialdehyde (MDA) levels were measured as a marker for lipid peroxidation. Compared with the control group, the MDA level was significantly increased after 8 weeks in the L-NAME-treated group. Rats treated with lisinopril and L-NAME plus lisinopril were found to have significantly decreased hippocampal MDA levels. Regarding the hippocampal concentrations of NR2A and NR2B, there were no statistically significant differences between groups. We demonstrated that lisinopril treatment has no direct regulatory effect on the levels of NR2A and NR2B in the rat hippocampus. Our results showed that Lisinopril could act as an antioxidant agent against hypertension-induced oxidative stress in rat hippocampus. The findings support that the use of lisinopril may offer a good alternative in the treatment of hypertension by reducing not only blood pressure but also prevent hypertensive complications in the brain.