We investigated the antihypertensive and antioxidant potential of vanillic acid (VA) in N(ω)-Nitro-L-arginine methyl ester hydrochloride (L-NAME) - treated adult male albino Wistar rats. Treatment of rats with L-NAME (40 mg/kg Bw for 30 days) caused a sustained increase in systolic- (SBP) and diastolic blood pressure (DBP) and significantly decreased the concentration of nitrite/nitrate (NO(x)) in plasma as compared with that in the control. Rats treated with VA restored SBP and DBP to normal level and preserve the plasma NO metabolites concentration. Moreover, VA reduced lipid peroxidation products (thiobarbituric acid reactive substances, lipid hydroperoxides, conjugated dienes) and significantly restored enzymatic antioxidants (superoxide dismutase, catalase, and glutathione peroxidase), non-enzymatic antioxidants (vitamin C, vitamin E, and reduced glutathione) in the plasma. To assess the toxicity if any of VA treatment, hepatic and renal function markers were measured. Our results showed that the effect at a dose of 50 mg/kg Bw of VA was more pronounced than that of the other two doses, 25 and 100 mg/kg Bw. These results were supported by histopathology studies. We conclude that VA possesses an antihypertensive and antioxidant activity in L-NAME-induced hypertensive rats.

Sulforaphane (SFN), a dietary phase-2 enzyme inducer that mitigates cellular oxidative stress through nuclear factor erythroid 2-related factor 2 (Nrf2) activation, is known to exhibit beneficial effects in the vessel wall. For instance, it inhibits vascular smooth muscle cell (VSMC) proliferation, a major event in atherosclerosis and restenosis after angioplasty. In particular, SFN attenuates the mitogenic and pro-inflammatory actions of platelet-derived growth factor (PDGF) and tumor necrosis factor-α (TNFα), respectively, in VSMCs. Nevertheless, the vasoprotective role of SFN has not been examined in the setting of obesity characterized by hyperleptinemia and insulin resistance. Using the mouse model of western diet-induced obesity, the present study demonstrates for the first time that subcutaneous delivery of SFN (0.5 mg/Kg/day) for ~3 weeks significantly attenuates neointima formation in the injured femoral artery [↓ (decrease) neointima/media ratio by ~60%; n = 5–8]. This was associated with significant improvements in metabolic parameters, including ↓ weight gain by ~52%, ↓ plasma leptin by ~42%, ↓ plasma insulin by ~63%, insulin resistance [↓ homeostasis model assessment of insulin resistance (HOMA-IR) index by ~73%], glucose tolerance (↓ AUCGTT by ~24%), and plasma lipid profile (e.g., ↓ triglycerides). Under in vitro conditions, SFN significantly decreased leptin-induced VSMC proliferation by ~23% (n = 5) with associated diminutions in leptin-induced cyclin D1 expression and the phosphorylation of p70S6kinase and ribosomal S6 protein (n = 3–4). The present findings reveal that, in addition to improving systemic metabolic parameters, SFN inhibits leptin-induced VSMC proliferative signaling that may contribute in part to the suppression of injury-induced neointima formation in diet-induced obesity.

Purpose Deregulation of polyamine metabolism has been implicated in various neurodegenerative disease and injury conditions. Studies from our laboratory have demonstrated that polyamine oxidation is a critical mediator of both neuronal and vascular injury in a mouse model of retinopathy of prematurity (Narayanan et al 2014; Patel et al 2016). The current study was undertaken to investigate the role of the polyamine oxidase spermine oxidase (SMO) in mediating neuronal damage and dysfunction in the diabetic retina. Methods Mice (8 weeks old, C57BL6J) were made diabetic by injection of streptozotocin (STZ, 65 mg/kg, pH 4.5, i.p.) and compared to age‐matched controls after 4 to 15 weeks of diabetes. Following the onset of hyperglycemia, mice were treated with either vehicle (normal saline) or SMO inhibitor, MDL 72527 (20 mg/kg of body weight, in saline, intra‐peritoneal, 3 times/week). Retinal neuronal function in living mice was determined by electroretinography (ERG). Retinal structure in the same mice was analyzed by Spectral Domain‐Optical Coherence Tomography (SD‐OCT). Following ERG and SD‐OCT analyses, mice were humanely euthanized, and retinas were collected and processed for immunofluorescence and western blot analyses. Results Western blot analysis showed that expression of SMO was increased in the diabetic retinas compared to controls. Inner retinal function studied by dark‐adapted electroretinography showed that the positive (pSTR) and negative (nSTR) scotopic threshold responses (measured at 110 ms and 200 ms), were significantly reduced (p<0.01, N=5–12) in the diabetic (4–12 weeks) mice as compared with the controls. The pSTR, but not the nSTR amplitudes were greatly improved in the MDL‐treated diabetic mice (p<0.05, N=5–10). The amplitude at 110 ms was dominated by the b‐wave at higher intensities and was significantly stronger in the MDL72527‐treated mice than in the vehicle‐treated diabetic mice. SD‐OCT analysis demonstrated a significant thinning of retina in the diabetic mice (p<0.01, N=5–12), which was improved in the MDL‐treated group. These data demonstrate a partial rescue of inner retinal function and retinal structure by SMO inhibition in the diabetic retina. Studies on the impact of MDL72527 treatment on neuronal survival are currently in progress. Conclusion Our results show the specific involvement of Spermine Oxidase in mediating neuronal injury in the diabetic retina and demonstrate its potential as a therapeutic target for mitigating neuronal injury in diabetic retinopathy. Support or Funding Information These studies supported by the National Eye Institute (1R01EY028569 to S.P.N) and Augusta University Culver Vision Discovery institute pilot grant to S.P.N. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.