Phospho-endothelial Nitric Oxide Research Articles

A low testosterone level impairs erectile function by increasing endocan expression in rat penile corpus cavernosum.

The mechanism by which a state of low testosterone leads to erectile dysfunction (ED) has not been determined. Endocan is a novel marker of endothelial function. However, whether endocan is involved in the regulation of erectile function under low testosterone levels remains unclear. In this study we sought to determine whether a low-testosterone state inhibits erectile function by regulating endocan expression in the endothelial cells of the rat penile corpus cavernosum. Thirty-six male Sprague-Dawley rats aged 8 weeks were randomly assigned to 6 groups (n = 6 per group) as follows: (1) control, (2) castration, (3) castration + testosterone treatment (treated with 3mg/kg testosterone propionate per 2days), (4) control + transfection (4weeks after castration, injected with lentiviral vector (1 × 108 transduction units/mL, 10μL), (5) castration + transfection, or (6) castration + empty transfection. One week after the injection, we measured the maximal intracavernous pressure/mean arterial pressure (ICPmax/MAP), serum testosterone and nitric oxide (NO) levels, and the expression of endocan, phospho-endothelial NO synthase (p-eNOS), eNOS, phospho-protein kinase B (p-AKT), and AKT in the rat penile corpus cavernosum. Under a low-androgen state, the expression of endocan in the rat penile corpus cavernosum was significantly increased, which inhibited the AKT/eNOS/NO signaling pathway and resulted in ED. In the castration group, the expression of endocan in the rat penile corpus cavernosum was significantly higher than that in the control group (P < .05). Additionally, the levels of p-AKT/AKT, p-eNOS/eNOS, and NO in the rat penile corpus cavernosum and ICPmax/MAP were significantly lower in the castration group than in the control group (P < .05). In the castration + transfection group compared with the castration group there was a significant decrease in the expression of endocan (P < .05) and an increase in the ratios of p-AKT/AKT, p-eNOS/eNOS, and ICPmax/MAP (P < .05) in the rat penile corpus cavernosum. Downregulating the expression of endocan in the penile corpus cavernosum may be a feasible approach for treating ED caused by hypoandrogenism. The results of this study indicte that endocan may affect NO levels and erectile function through multiple signaling pathways, but further experiments are needed to clarify the relationship between endocan and androgens. A low-testosterone state inhibits the AKT/eNOS/NO signaling pathway by increasing the expression of endocan in the rat penile corpus cavernosum and impairing erectile function in rats. Decreasing the expression of endocan in the penile corpus cavernosum can improve erectile function in rats with low testosterone levels.

Effects of diet-induced metabolic syndrome on cardiac function and angiogenesis in response to the sodium-glucose cotransporter-2 inhibitor canagliflozin

IntroductionSodium-glucose cotransporter-2 inhibitors are antidiabetic medications that have been shown to decrease cardiovascular events and heart failure-related mortality in clinical studies. We attempt to examine the complex interplay between metabolic syndrome and the sodium-glucose cotransporter-2 inhibitor canagliflozin (CAN) in a clinically relevant model of chronic myocardial ischemia. MethodsTwenty-one Yorkshire swine were fed a high-fat diet starting at 6 weeks of age to induce metabolic syndrome. At 11 weeks, all underwent placement of an ameroid constrictor around the left circumflex coronary artery to induce chronic myocardial ischemia. After 2 weeks, swine received either control (CON) (n = 11) or CAN 300 mg by mouth daily (n = 10) for 5 weeks, whereupon all underwent terminal harvest. ResultsThere was a significant increase in cardiac output and heart rate with a decrease in pulse pressure in the CAN group compared with CON (all P values < .05). The CAN group had a significant increase in capillary density (P = .02). There was no change in myocardial perfusion or arteriolar density. CAN induced a significant increase in markers of angiogenesis, including Phospho-endothelial nitric oxide synthase, Endothelial nitric oxide synthase, vascular endothelial growth factor receptor-1, heat shock protein 70, and extracellular signal-regulated kinases (all P values < .05), plausibly resulting in capillary angiogenesis. ConclusionsCAN treatment leads to a significant increase in capillary density and augmented cardiac function in a swine model of chronic myocardial ischemia in the setting of metabolic syndrome. This work further elucidates the mechanism of sodium-glucose cotransporter-2 inhibitors in patients with cardiac disease; however, more studies are needed to determine if this increase in capillary density plays a role in the improvements seen in clinical studies.

Cediranib ameliorates portal hypertensive syndrome via inhibition of VEGFR-2 signaling in cirrhotic rats

Portal hypertension (PHT) is a syndrome caused by systemic and portal hemodynamic disturbances with the progression of cirrhosis. However, the exact mechanisms regulating angiogenesis-related responses in PHT remain unclear. Cediranib is a potent inhibitor of vascular endothelial growth factor receptor (VEGFR) tyrosine kinases, exhibiting a greater affinity for VEGFR-2. Liver cirrhosis was induced by common bile duct ligation (BDL) in Sprague–Dawley rats. Sham-operated rats were controls. BDL and sham rats were randomly allocated to receive Cediranib or vehicle after BDL. On the 28th day, portal hypertension related parameters were surveyed. Cediranib treatment could significantly reduce the portal pressure (PP) in BDL rats, while it did not affect the mean arterial pressure (MAP) in sham groups and BDL groups. Cediranib treatment could significantly affect the stroke volume (SV), cardiac output (CO), cardiac index (CI), systemic vascular resistance (SVR), superior mesenteric artery (SMA) flow and SMA resistance in BDL groups and BDL with Cediranib groups. Cediranib treatment could improve the mesenteric vascular remodeling and contractility. Cediranib treatment significantly reduced mesenteric vascular density. And phospho-VEGFR-2 was significantly downregulated by Cediranib. On the other hand, phospho-endothelial Nitric Oxide Synthases (phospho-eNOS) expressions were upregulated. Cediranib not only improved splanchnic hemodynamics, extrahepatic vascular remodeling and vasodilation, but also alleviated intrahepatic fibrosis and collagen deposition significantly. Cediranib treatment could reduce intrahepatic angiogenesis between BDL-vehicle and BDL-Cediranib rats. In conclusion, Cediranib could improve extrahepatic hyperdynamic circulation by inhibiting extrahepatic angiogenesis through inhibition of the VEGFR-2 signaling pathway, portal collateral circulation formation, as well as eNOS-mediated vasodilatation and vascular remodeling, and at the same time, Cediranib improved intrahepatic fibrogenesis and angiogenesis, which together alleviate cirrhotic PHT syndrome.

Homoplantaginin attenuates high glucose-induced vascular endothelial dysfunction via inhibiting store-operated calcium entry channel and endoplasmic reticulum stress.

The activation of store-operated calcium entry (SOCE) channel and endoplasmic reticulum stress (ERS) induced by high glucose (HG) is recognized as a major cause of vascular endothelial dysfunction. This study aims to investigate the protective effect of homoplantaginin (Hom) on HG-induced endothelial dysfunction. HG-induced vascular endothelial dysfunction model in human umbilical vein endothelial cells (HUVECs) and rat-isolated thoracic aortas were established to observe the protective effect of Hom, further evaluated the mechanism of SOCE channel and ERS in the pathogenesis. Hom increased the levels of nitric oxide (NO) and phospho-endothelial nitric oxide synthase (p-eNOS) in HUVECs and isolated rat thoracic aortas in a dose-dependent manner, restored acetylcholine-mediated endothelium-dependent vasodilation. Network pharmacology showed that the pathogenesis of diabetic vascular complications may involve calcium (Ca2+) signal pathway. Hom reduced Ca2+ concentration via blocking SOCE channel in HUVECs, and resisted ERS activation by down-regulating ERS-related proteins expression. Importantly, SKF96365 (SOCE inhibitor) intervention experiment showed that Hom inhibited ERS activation by blocking the SOCE channel, further increased the levels of NO and p-eNOS. Hom could alleviate HG-induced vascular endothelial dysfunction by inhibiting SOCE channel and ERS. This provided a potential pharmacological intervention strategy for the treatment of vascular endothelial dysfunction.

Liraglutide provides cardioprotection through the recovery of mitochondrial dysfunction and oxidative stress in aging hearts.

Glucagon-like peptide-1 receptor (GLP-1R) agonists improve cardiovascular dysfunction via the pleiotropic effects behind their receptor action. However, it is unknown whether they have a cardioprotective action in the hearts of the elderly. Therefore, we examined the effects of GLP-1R agonist liraglutide treatment (LG, 4weeks) on the systemic parameters of aged rats (24-month-old) compared to those of adult rats (6-month-old) such as electrocardiograms (ECGs) and systolic and diastolic blood pressure (SBP and DBP). At the cellular level, the action potential (AP) parameters, ionic currents, and Ca2+ regulation were examined in freshly isolated ventricular cardiomyocytes. The LG treatment of aged rats significantly ameliorated the prolongation of QRS duration and increased both SBP and DBP together with recovery in plasma oxidant and antioxidant statuses. The prolonged AP durations and depolarized membrane potentials of the isolated cardiomyocytes from the aged rats were normalized via recoveries in K+ channel currents with LG treatment. The alterations in Ca2+ regulation including leaky-ryanodine receptors (RyR2) could be also ameliorated via recoveries in Na+/Ca2+ exchanger currents with this treatment. A direct LG treatment of isolated aged rat cardiomyocytes could recover the depolarized mitochondrial membrane potential, the increase in both reactive oxygen and nitrogen species (ROS and RNS), and the cytosolic Na+ level, although the Na+ channel currents were not affected by aging. Interestingly, LG treatment of aged rat cardiomyocytes provided a significant inhibition of activated sodium-glucose co-transporter-2 (SGLT2) and recoveries in the depressed insulin receptor substrate 1 (IRS1) and increased protein kinase G (PKG). The recovery in the ratio of phospho-endothelial nitric oxide (pNOS3) level to NOS3 protein level in LG-treated cardiomyocytes implies the involvement of LG-associated inhibition of oxidative stress-induced injury via IRS1-eNOS-PKG pathway in the aging heart. Overall, our data, for the first time, provide important information on the direct cardioprotective effects of GLP-1R agonism with LG in the hearts of aged rats through an examination of recoveries in mitochondrial dysfunction, and both levels of ROS and RNS in left ventricular cardiomyocytes.

Berberine promotes the viability of random skin flaps via the PI3K/Akt/eNOS signaling pathway.

Random skin flaps are often used in reconstruction operations. However, flap necrosis is still a common postoperative complication. Here, we investigated whether berberine (C20 H19 NO5 , BBR), a drug with antioxidant activity, improves the survival rate of random flaps. Fifty-four rats were divided into three groups: control, BBR and BBR +L -NAME groups (L -NAME, L -NG -Nitro-arginine methyl ester). The survival condition and the percentage of survival area of the flaps were evaluated on the seventh day after surgery. After animals were sacrificed, angiogenesis, apoptosis, oxidative stress and inflammation levels were assessed by histological and protein analyses. Our findings suggest that berberine promotes flap survival. The level of angiogenesis increased; the levels of oxidative stress, inflammation and apoptosis decreased; the levels of phosphoinositide 3-kinase (PI3K), phospho-Akt (p-Akt) and phospho-endothelial nitric oxide synthase (p-eNOS) increased in the flap tissue; and L -NAME reversed the effects of berberine on random skin flaps. Statistical analysis showed that the BBR group results differed significantly from those of the control and the BBR +L -NAME groups (p< .05). Our results confirm that berberine is an effective drug for significantly improving the survival rate of random skin flaps by promoting angiogenesis, inhibiting inflammation, attenuating oxidative stress, and reducing apoptosis through the PI3K/Akt/eNOS signaling pathway.

Potential mechanistic pathways underlying intestinal and hepatic effects of kefir in high-fructose-fed rats

Excess intake of fructose may contribute to the high prevalence of metabolic disorder. In this study, we investigated the effects of kefir supplementation on the intestine-liver-adipose tissue axis in metabolic disorder induced by high-fructose diet in rats to describe mechanistic action and potential therapeutic value of kefir. Fructose was given to the rats as a 20% solution in drinking water for 15 weeks. Kefir was administrated by gastric gavage once a day during the final six weeks. Kefir supplementation improved metabolic parameters, including plasma triglyceride and insulin levels; hepatic weight, triglyceride content and fatty degeneration; omental fat mass in fructose-fed rats. Kefir supplementation decreased the ratio of Firmicutes/Bacteroidetes in feces, as well as necrotic degeneration, expression levels of nuclear factor-kappa B (NF-κB), and inducible nitric oxide synthase (iNOS), but increased expression of tight-junction proteins occludin and claudin-1, in the ileum of the fructose-fed rats. Kefir treatment also reduced the mRNA levels of key lipogenic genes sterol regulatory element-binding protein (SREBP-1c) and fatty acid synthase (FASN) together with a decline in expression of tumor necrosis factor-alpha (TNF-α), NF-κB, and glycosylated glycoprotein (CD68) in the liver. Moreover, kefir treatment improved insulin signaling at the level of insulin receptor substrate 1 (IRS-1) and phospho-endothelial nitric oxide synthase (peNOS) as well as fructose transporters (GLUT2 and GLUT5) in the liver, but not in the adipose tissue, of high-fructose-fed rats. Consequently, kefir supplementation suppresses hepatic lipogenesis and inflammatory status, but promotes insulin signaling, in association with a change of the fecal microbiota and attenuation of the intestinal permeability factors in high-fructose-fed rats. Thus, we propose that kefir has favorable effects on the hepatic and intestinal irregularities induced by fructose overconsumption.

Trehalose protects the endothelium from cadmium-induced dysfunction.

The objective of the present study is to identify the possible regulatory role of trehalose (Tre) against cadmium chloride (CdCl2 )-induced endothelial cell dysfunction. To screen the dose-dependent effect of both Tre and CdCl2 , amethylthiazolyldiphenyl-tetrazolium bromide (MTT) assay was performed. Interestingly, MTT assay results have shown that co-incubation of Tre (1 mM) with CdCl2 significantly decreased the CdCl2 (5 µM) cytotoxicity. Nitric oxide (NO) measurement using Griess assay and 4-amino-5-methylamino-2',7'-difluorofluoresceinfluorescence probe results have shown that CdCl2 decreases NO production in endothelial cells. Western blotting analysis results showed that CdCl2 decreases endothelial nitric oxide synthase (eNOS) and phospho endothelial nitric oxide synthase (peNOS) expression. The present study results have also observed that CdCl2 treatment increases reactive oxygen species (ROS) production. However, combination treatment (Tre + CdCl2 ) could restore the NO production in CdCl2 -treated cells. In addition, combination treatment could also restore eNOS and peNOS expression in endothelial cells. Moreover, Tre treatment was found to decrease CdCl2 -induced ROS production. Collectively, the present study results demonstrate that Tre possesses a significant protective action against CdCl2 -mediated endothelial dysfunction by increasing NO production, eNOSand peNOS expression, and by decreasing oxidative stress.

Ethinyl estradiol sulfate acts without fluid resuscitation through estrogen receptors to rapidly protect the cardiovascular system from severe hemorrhage.

Our in vivo rodent and pig model evidenced that estrogen and its derivative, ethinyl estradiol sulfate (EES), promote survival following hemorrhagic shock. To determine its mechanism, we first confirmed EES binding to estrogen receptor (ER) and improving/restoring cellular signaling, countering the assumption that EES, an ethinyl estradiol metabolite, is inactive. In addition, we examined if EES acts rapidly, consistent with nongenomic signaling. We selected the biomarkers of cardiovascular performance, reduction of apoptosis and proinflammatory responses, and elaboration of nitric oxide (NO) to validate efficacy. A rat trauma-hemorrhage model, consisting of a midline laparotomy and controlled bleeding (60% blood loss) without fluid resuscitation, was used. At 30 minutes after hemorrhage, heart performance was monitored, and Western blots were used to quantify biochemical analytes. The specificity of EES for ER was profiled with ER antagonists. Binding studies by Sekisui XenoTech (Kansas City, KS) determined an LD50 value for EES binding the rat ER. The EES IC50 value was 1.52 × 10-8 Mol/L, consistent with pharmacologic efficacy. Ethinyl estradiol sulfate raised mean arterial pressure and ±derivative of pressure over time (dP/dT) significantly (but did not fully restore) within a 30-minute window. Levels of apoptosis and activation of NF-κB were dramatically reduced, as was elaboration of nitric oxide (NO) by inducible nitric oxide synthase. Phospho-endothelial nitric oxide synthase (eNOS) was restored to physiological levels. The restoration of cellular signaling occurs before restoration of cardiac contractility. Ethinyl estradiol sulfate is a potent drug for improving heart performance, which also dramatically reduces damage by apoptosis, proinflammatory activity, and NO production, validating that EES can blunt multiple harmful outcomes arising from hypoxia and hypovolemia. The actions are dependent on receptor engagement, where specificity is confirmed by ER antagonists. The constraint of a 30-minute sampling window affirms that the responses are nongenomic and very likely restricted to cell-surface receptor engagement. The rapidity of these responses makes EES promising for intervention in the "golden hour."

Cathepsin S-Mediated Negative Regulation of Wnt5a/SC35 Activation Contributes to Ischemia-Induced Neovascularization in Aged Mice.

Given that cathepsin S (CatS) gained attention due to its enzymatic and non-enzymatic functions in signaling, the role of CatS in ischemia-induced angiogenesis of aged mice was explored.Methods and Results:To study the role of CatS in the decline in aging-related vascular regeneration capacity, a hindlimb ischemia model was applied to aged wild-type (CatS+/+) and CatS-deficient (CatS-/-) mice. CatS-/-mice exhibited impaired blood flow recovery and capillary formation and increased levels of p-insulin receptor substrate-1, Wnt5a, and SC35 proteins and decreased levels of phospho-endothelial nitric oxide synthase (p-eNOS), p-mTOR, p-Akt, p-ERK1/2, p-glycogen synthase kinase-3α/β, and galatin-3 proteins, as well as decreased macrophage infiltration and matrix metalloproteinase-2/-9 activities in the ischemic muscles. In vitro, CatS knockdown altered the levels of these targeted essential molecules for angiogenesis. Together, the results suggested that CatS-/-leads to defective endothelial cell functions and that CatS-/-is associated with decreased circulating endothelial progenitor cell (EPC)-like CD31+/c-Kit+cells. This notion was reinforced by the study finding that pharmacological CatS inhibition led to a declined angiogenic capacity accompanied by increased Wnt5a and SC35 levels and decreased eNOS/Akt-ERK1/2 signaling in response to ischemia. These findings demonstrated that the impairment of ischemia-induced neovascularization in aged CatS-/-mice is due, at least in part, to the attenuation of endothelial cell/EPC functions and/or mobilization associated with Wnt5a/SC35 activation in advanced age.

Ginkgolide A protects adverse cardiac remodeling through enhancing antioxidation and nitric oxide utilization in mice with pressure overload.

In this study, we aimed to explore whether ginkgolide A (GA) would exhibit cardio-protective effects in mice with pressure overload through enhancing antioxidation and nitric oxide (NO) bioavailability. 21 male mice were randomly assigned into three groups as follows: sham group (10 ml/kg/day PBS, n=7), transverse aortic constriction (TAC) group (TAC and 10 ml/kg/day PBS, n=7) and GA group (TAC and 20 mg/kg/day GA, n=7). All groups received an intraperitoneal injection for four weeks. Heart and body mass were measured. Cardiac function was assessed by echocardiography. The collagen deposition, area of cardiomyocytes, number of capillaries and cell apoptosis were evaluated using Masson's staining, WGA staining, CD31 staining and TUNEL assay, respectively. Cadiac oxidative and antioxidative indexes were measured by colorimetry. Nitrotyrosine (NT) and transforming growth factor-β (TGF-β) were determined by ELISA. Phospho-endothelial NO synthases (eNOS) (Ser1177), phospho-eNOS (Thr 495), eNOS, neuronal NOS (nNOS), inducible NOS (iNOS) and GAPDH were analyzed by western blot. GA treatment greatly improved cardiac dysfunction, suppressed cardiac hypertrophy and increased capillary number at 4 weeks after TAC (P<0.05). Fibrotic area, cardiomyocyte area, and cell apoptosis of GA group were declined notably as compared to those of TAC group (P<0.05). GA administration substantially attenuated cardiac oxidative stress, and reduced NT and TGF-β levels (P<0.05). Besides, GA medication can enhance eNOS signaling, resulting in increased cardiac NO production (P<0.05). GA had a cardioprotective effect in mice with pressure overload, which was closely related with reducing oxidative stress and enhancing NO bioavailability in hearts.

The Possibility of Urinary Liver-Type Fatty Acid-Binding Protein as a Biomarker of Renal Hypoxia in Spontaneously Diabetic Torii Fatty Rats

Background: Renal hypoxia is an aggravating factor for tubulointerstitial damage, which is strongly associated with renal prognosis in diabetic kidney disease (DKD). Therefore, urinary markers that can detect renal hypoxia are useful for monitoring DKD. Objective: To determine the correlation between urinary liver-type fatty acid-binding protein (L-FABP) and renal hypoxia using a novel animal model of type 2 diabetes. Methods: Male spontaneously diabetic Torii (SDT) fatty rats (n = 6) were used as an animal model of type 2 diabetes. Age- and sex-matched Sprague-Dawley (SD) rats (n = 8) were used as controls. Body weight, systolic blood pressure, and blood glucose levels were measured at 8, 12, 16, and 24 weeks of age. Urine samples and serum and kidney tissues were collected at 24 weeks of age. Microvascular blood flow index (BFI) was measured using diffuse correlation spectroscopy before sampling both the serum and kidneys for the evaluation of renal microcirculation at the corticomedullary junction. Results: Obesity, hyperglycemia, and hypertension were observed in the SDT fatty rats. Focal glomerular sclerosis, moderate interstitial inflammation, and fibrosis were significantly more frequent in SDT fatty rats than in SD rats. While the frequency of peritubular endothelial cells and phosphoendothelial nitric oxide synthase levels were similar in both types of rats, the degree of renal hypoxia-inducible factor-1α (HIF-1α) expression was significantly higher (and with no change in renal vascular endothelial growth factor expression levels) in the SDT fatty rats. Urinary L-FABP levels were significantly higher and renal microvascular BFI was significantly lower in the SDT fatty rats than in the SD rats. Urinary L-FABP levels exhibited a significant positive correlation with renal HIF-1α expression and a significant negative correlation with renal microvascular BFI. Conclusions: Urinary L-FABP levels reflect the degree of renal hypoxia in DKD in a type 2 diabetic animal model. Urinary L-FABP may thus prove useful as a renal hypoxia marker for monitoring DKD in patients with type 2 diabetes in clinical practice.

Extracellular Vesicle Injection Improves Myocardial Function and Increases Angiogenesis in a Swine Model of Chronic Ischemia.

BackgroundMesenchymal stem cell–derived extracellular vesicles (EVs) are believed to be cardioprotective in myocardial infarct. The objective of this study was to examine the effects of human mesenchymal cell–derived EV injection on cardiac function, myocardial blood flow, and vessel density in the setting of chronic myocardial ischemia.Methods and ResultsTwenty‐three Yorkshire swine underwent placement of an ameroid constrictor on their left circumflex artery. Two weeks later, the animals were split into 2 groups: the control group (CON; n=7) and the EV myocardial injection group (MVM; n=10). The MVM group underwent myocardial injection of 50 μg of EVs in 2 mL 0.9% saline into the ischemic myocardium. Five weeks later, the pigs underwent a harvest procedure, and the left ventricular myocardium was analyzed. Absolute blood flow and the ischemic/nonischemic myocardial perfusion ratio were increased in the ischemic myocardium in the MVM group compared with the CON group. Pigs in the MVM group had increased capillary and arteriolar density in the ischemic myocardial tissue compared with CON pigs. There was an increase in expression of the phospho–mitogen‐activated protein kinase/mitogen‐activated protein kinase ratio, the phospho–endothelial nitric oxide synthase/endothelial nitric oxide synthase ratio, and total protein kinase B in the MVM group compared with CON. There was an increase in cardiac output and stroke volume in the MVM group compared with CON.ConclusionsIn the setting of chronic myocardial ischemia, myocardial injection of human mesenchymal cell–derived EVs increases blood flow to ischemic myocardial tissue by induction of capillary and arteriolar growth via activation of the protein kinase B/endothelial nitric oxide synthase and mitogen‐activated protein kinase signaling pathways resulting in increased cardiac output and stroke volume.

Macrophage Depletion Lowered Blood Pressure and Attenuated Hypertensive Renal Injury and Fibrosis.

Monocyte/macrophage recruitment is closely associated with the degree of hypertensive renal injury. We investigated the direct role of macrophages using liposome-encapsulated clodronate (LEC) to deplete monocytes/macrophages in hypertensive renal injury. C57BL/6 mice were treated with a pressor dose of angiotensin (Ang, 1.4 mg/kg/day) II plus LEC or the PBS-liposome for 2 weeks. Ang II mice developed hypertension, albuminuria, glomerulosclerosis, and renal fibrosis. LEC treatment reduced systolic blood pressure (SBP), albuminuria, and protected against renal structural injury in Ang II mice. Ang II significantly increased renal macrophage infiltration (MOMA2+ cells) and the expression of renal tumor necrosis factor α and interleukin β1, which were significantly reduced in Ang II/LEC mice. Ang II increased renal oxidative stress and the expression of profibrotic factors transforming growth factor (TGF) β1 and fibronectin. Ang II also inhibited the phosphorylation of endothelial nitric oxide synthase [phospho-endothelial nitric oxide synthesis (eNOS), ser1177]. LEC treatment reduced renal oxidative stress and TGFβ1 and fibronectin expressions, and increased phospho-eNOS expression in the Ang II mice. In Dahl rats of salt-sensitive hypertension, LEC treatment for 4 weeks significantly attenuated the elevation of SBP induced by high salt intake and protected against renal injury and fibrosis. Our results demonstrate that renal macrophages play a critical role in the development of hypertension and hypertensive renal injury and fibrosis; the underlying mechanisms may be involved in the reduction in macrophage-driven renal inflammation and restoration of the balance between renal oxidative stress and eNOS. Therefore, macrophages should be considered as a potential therapeutic target to reduce the adverse consequences of hypertensive renal diseases.

Deleterious effects of phosphate on vascular and endothelial function via disruption to the nitric oxide pathway.

BackgroundHyperphosphataemia is an independent risk factor for accelerated cardiovascular disease in chronic kidney disease (CKD), although the mechanism for this is poorly understood. We investigated the effects of sustained exposure to a high-phosphate environment on endothelial function in cellular and preclinical models, as well as in human subjects.MethodsResistance vessels from rats and humans (± CKD) were incubated in a normal (1.18 mM) or high (2.5 mM) phosphate concentration solution and cells were cultured in normal- (0.5 mM) or high-phosphate (3 mM) concentration media. A single-blind crossover study was performed in healthy volunteers, receiving phosphate supplements or a phosphate binder (lanthanum), and endothelial function measured was by flow-mediated dilatation.ResultsEndothelium-dependent vasodilatation was impaired when resistance vessels were exposed to high phosphate; this could be reversed in the presence of a phosphodiesterase-5-inhibitor. Vessels from patients with CKD relaxed normally when incubated in normal-phosphate conditions, suggesting that the detrimental effects of phosphate may be reversible. Exposure to high-phosphate disrupted the whole nitric oxide pathway with reduced nitric oxide and cyclic guanosine monophosphate production and total and phospho endothelial nitric oxide synthase expression. In humans, endothelial function was reduced by chronic phosphate loading independent of serum phosphate, but was associated with higher urinary phosphate excretion and serum fibroblast growth factor 23.ConclusionsThese directly detrimental effects of phosphate, independent of other factors in the uraemic environment, may explain the increased cardiovascular risk associated with phosphate in CKD.

Testosterone improves erectile function through inhibition of reactive oxygen species generation in castrated rats.

Testosterone is overwhelmingly important in regulating erectile physiology. However, the associated molecular mechanisms are poorly understood. The purpose of this study was to explore the effects and mechanisms of testosterone in erectile dysfunction (ED) in castrated rats. Forty male Sprague-Dawley rats were randomized to four groups (control, sham-operated, castration and castration-with-testosterone-replacement). Reactive oxygen species (ROS) production was measured by dihydroethidium (DHE) staining. Erectile function was assessed by the recording of intracavernous pressure (ICP) and mean arterial blood pressure (MAP). Protein expression levels were examined by western blotting. We found that castration reduced erectile function and that testosterone restored it. Nitric oxide synthase (NOS) activity was decrease in the castrated rats, and testosterone administration attenuated this decrease (each p < 0.05). The testosterone, dihydrotestosterone, cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) concentrations were lower in the castrated rats, and testosterone restored these levels (each p < 0.05). Furthermore, the cyclooxygenase-2 (COX-2) and prostacyclin synthase (PTGIS) expression levels and phospho-endothelial nitric oxide synthase (p-eNOS, Ser1177)/endothelial nitric oxide synthase (eNOS) ratio were reduced in the castrated rats compared with the controls (each p < 0.05). In addition, the p40phox and p67phox expression levels were increased in the castrated rats, and testosterone reversed these changes (each p < 0.05). Overall, our results demonstrate that testosterone ameliorates ED after castration by reducing ROS production and increasing the activity of the eNOS/cGMP and COX-2/PTGIS/cAMP signaling pathways.

Antioxidative mechanism of Lycium barbarum polysaccharides promotes repair and regeneration following cavernous nerve injury.

Polysaccharides extracted from Lycium barbarum exhibit antioxidant properties. We hypothesized that these polysaccharides resist oxidative stress-induced neuronal damage following cavernous nerve injury. In this study, rat models were intragastrically administered Lycium barbarum polysaccharides for 2 weeks at 1, 7, and 14 days after cavernous nerve injury. Serum superoxide dismutase and glutathione peroxidase activities significantly increased at 1 and 2 weeks post-injury. Serum malondialdehyde levels decreased at 2 and 4 weeks. At 12 weeks, peak intracavernous pressure, the number of myelinated axons and nicotinamide adenine dinucleotide phosphate-diaphorase-positive nerve fibers, levels of phospho-endothelial nitric oxide synthase protein and 3-nitrotyrosine were higher in rats administered at 1 day post-injury compared with rats administered at 7 and 14 days post-injury. These findings suggest that application of Lycium barbarum polysaccharides following cavernous nerve crush injury effectively promotes nerve regeneration and erectile functional recovery. This neuroregenerative effect was most effective in rats orally administered Lycium barbarum polysaccharides at 1 day after cavernous nerve crush injury.

Effect of Adenoviral Catalase Gene Transfer on Renal Ischemia/Reperfusion Injury in Rats.

Ischemia/reperfusion (I/R) may through overt H₂O₂-induced pathophysiologic mechanisms lead to renal dysfunction. We explore whether catalase (CAT) protein overexpression by adenoviral CAT gene (Adv-CAT) transfection may improve ischemia/reperfusion-induced renal dysfunction. We augmented renal CAT expression by intrarenal arterial Adv-CAT administration with renal venous clamping in avertin-anesthetized female Wistar rats. After Adv-CAT transfection, we examined the CAT expression, location and effects on blood urea nitrogen (BUN) and urinary tubular injury biomarkers by biochemical assays, microcirculation by a laser perfusion imager, renal H₂O₂ amount by a chemiluminescent analyzer and molecular mechanisms including cytosolic cytochrome C leakage, apoptosis, autophagy and phospho- Akt (p-Akt)/phospho-endothelial nitric oxide (p-eNOS)/nitric oxide (NO) signaling by western blotting, immunohistochemistry and immunofluorescence. Adv-CAT enhanced 2.6-fold renal CAT protein expression primarily located in the proximal and distal tubules and renal vessels. Ischemia/reperfusion increased cytosolic cytochrome C leakage, renal H₂O₂-dependent level, autophagic Beclin-1/Atg5-Atg12/LC3 II expression, apoptotic Bax/Bcl-2/caspase 3/poly-(ADP-ribose)-polymerase fragments (PARP) expression and terminal deoxynucleotidyl transferasemediated nick-end labeling (TUNEL) stains and BUN and urinary glutathione S-transferase (GST) levels leading to proximal tubular injury. Ischemia/reperfusion also decreased renal microvascular blood flow associated with the inhibited renal expression of p-Akt and p-eNOS and NO production. Adv-CAT significantly improved the reduction in renal microvascular blood flow, reduced ischemia/reperfusion-enhanced oxidative stress, Beclin-1/Atg5-Atg12/LC3 II-meidated autophagy, Bax/Bcl-2/caspase 3/PARP-mediated apoptotic signaling, TUNEL stains, urinary GST level, and restored the p-Akt/p-eNOS/NO signaling in the kidney. Treatment of phosphatidylinositol 3-kinase inhibitors, wortmannin and LY294002, deleted Adv-CAT-induced p-Akt/p-eNOS/NO protective signaling. In conclusion, our results suggest Adv-CAT gene transfer counteracts H₂O₂-induced ischemia/reperfusion injury through preserving p-Akt/p-eNOS/NO pathway in the rat kidney.

Endothelial PPAR-γ provides vascular protection from IL-1β-induced oxidative stress.

Loss of peroxisome proliferator-activated receptor (PPAR)-γ function in the vascular endothelium enhances atherosclerosis and NF-κB target gene expression in high-fat diet-fed apolipoprotein E-deficient mice. The mechanisms by which endothelial PPAR-γ regulates inflammatory responses and protects against atherosclerosis remain unclear. To assess functional interactions between PPAR-γ and inflammation, we used a model of IL-1β-induced aortic dysfunction in transgenic mice with endothelium-specific overexpression of either wild-type (E-WT) or dominant negative PPAR-γ (E-V290M). IL-1β dose dependently decreased IκB-α, increased phospho-p65, and increased luciferase activity in the aorta of NF-κB-LUC transgenic mice. IL-1β also dose dependently reduced endothelial-dependent relaxation by ACh. The loss of ACh responsiveness was partially improved by pretreatment of the vessels with the PPAR-γ agonist rosiglitazone or in E-WT. Conversely, IL-1β-induced endothelial dysfunction was worsened in the aorta from E-V290M mice. Although IL-1β increased the expression of NF-κB target genes, NF-κB p65 inhibitor did not alleviate endothelial dysfunction induced by IL-1β. Tempol, a SOD mimetic, partially restored ACh responsiveness in the IL-1β-treated aorta. Notably, tempol only modestly improved protection in the E-WT aorta but had an increased protective effect in the E-V290M aorta compared with the aorta from nontransgenic mice, suggesting that PPAR-γ-mediated protection involves antioxidant effects. IL-1β increased ROS and decreased the phospho-endothelial nitric oxide synthase (Ser(1177))-to-endothelial nitric oxide synthase ratio in the nontransgenic aorta. These effects were completely abolished in the aorta with endothelial overexpression of WT PPAR-γ but were worsened in the aorta with E-V290M even in the absence of IL-1β. We conclude that PPAR-γ protects against IL-1β-mediated endothelial dysfunction through a reduction of oxidative stress responses but not by blunting IL-1β-mediated NF-κB activity.

Protective effects of Brassica oleracea sprouts extract toward renal damage in high-salt-fed SHRSP: role of AMPK/PPARα/UCP2 axis.

Renal damage precedes occurrence of stroke in high-sodium/low-potassium-fed stroke-prone spontaneously hypertensive rat (SHRSP). We previously reported a marked suppression of uncoupling protein-2 (UCP2) upon high-salt Japanese-style diet in SHRSP kidneys. Vegetable compounds are known to exert protective effects in cardiovascular diseases. We aimed at evaluating the impact of Brassica oleracea sprouts juice toward renal damage in Japanese diet-fed SHRSP and exploring the role of 5'-adenosine monophosphate-activated protein kinase (AMPK)/NAD-dependent deacetylase sirtuin-1 (SIRT1)/peroxisome proliferator-activated receptor-γ coactivator-1α (PGC1α)/peroxisome proliferator-activated receptor-α (PPARα)/UCP2 axis. SHRSP received Japanese diet for 4 weeks. A group of SHRSP received Japanese diet and B. oleracea. A third group received Japanese diet, B. oleracea, and PPARα inhibitor (GW6471). A group of SHRSP fed with regular diet served as control. Japanese diet induced marked increases of oxidative stress, inflammation, and proteinuria, along with glomerular and tubular damage, as compared with regular diet. A significant suppression of AMPK/UCP2 pathway was observed. Despite Japanese diet feeding, concomitant administration of B. oleracea prevented oxidative stress accumulation, inflammation, renal damage, and proteinuria. All components of the UCP2 regulatory pathway were significantly increased by B. oleracea. Superoxide dismutase 2 and phosphoendothelial nitric oxide synthase were also stimulated. Addition of PPARα inhibitor to B. oleracea and Japanese diet significantly reduced the B. oleracea beneficial effects. SBP levels were comparable among the different groups of rats.In vitro, UCP2 inhibition by genipin offset the antioxidant effect of B. oleracea in renal mesangial and proximal tubular cells. B. oleracea administration prevented renal damage in salt-loaded SHRSP, independently from SBP, with parallel stimulation of AMPK/SIRT1/PGC1α/PPARα/UCP2 axis. Stimulation of the latter mechanism may provide relevant renal protective effect and play a therapeutic role in target organ damage progression in hypertension.