Capsaicin pretreatment attenuates salt-sensitive hypertension by alleviating AMPK/Akt/Nrf2 pathway in hypothalamic paraventricular nucleus.

Background: Long term hypertension seriously promotes target organ damage in the brain and heart, and has increasingly become serious public health problem worldwide. The anti-hypertensive effects of capsaicin has been reported, however, the role and mechanism of capsaicin within the brain on salt-induced hypertension have yet to be elucidated. This study aimed to verify the hypothesis that capsaicin attenuates salt-induced hypertension via the AMPK/Akt/Nrf2 pathway in hypothalamic paraventricular nucleus (PVN). Methods: Dahl salt-sensitive (Dahl S) rats were used as animal model for the present study. Rats were randomly divided into four groups based on their dietary regimen (0.3% normal salt diet and 8% high salt diet) and treatment methods (infusion of vehicle or capsaicin in the PVN). Capsaicin was chronically administered in the PVN throughout the animal experiment phase of the study that lasted 6 weeks. Results: Our results demonstrated that PVN pretreatment with capsaicin can slow down raise of the blood pressure elevation and heart rate (HR) of Dahl S hypertensive rats given high salt diet. Interestingly, the cardiac hypertrophy was significantly improved. Furthermore, PVN pretreatment with capsaicin induced decrease in the expression of mRNA expression of NADPH oxidase-2 (NOX2), inducible nitric oxide synthase (iNOS), NOX4, p-IKKß and proinflammatory cytokines and increase in number of positive cell level for Nrf2 and HO-1 in the PVN of Dahl S hypertensive rats. Additionally, the protein expressions of phosphatidylinositol 3-kinase (p-PI3K) and phosphorylated protein kinase-B (p-AKT) were decreased, phosphorylated adenosine monophosphate-activated protein kinase (p-AMPK) were increased after the PVN pretreatment with capsaicin. Conclusion: Capsaicin pretreatment attenuates salt-sensitive hypertension by alleviating AMPK/Akt/iNOS pathway in the PVN.

Capsaicin improves hypertension and cardiac hypertrophy via SIRT1/NF-κB/MAPKs pathway in the hypothalamic paraventricular nucleus.

BACKGROUND: Hypertension has seriously affected a large part of the adult and elderly population. The complications caused by hypertension are important risk factors for cardiovascular disease accidents. Capsaicin, a pungent component of chili pepper has been revealed to improve hypertension. However, its potential mechanism in improving hypertension remains to be explored. PURPOSE: In the present study, we aimed to investigate whether capsaicin could attenuate the SIRT1/NF-κB/MAPKs pathway in the paraventricular nucleus of hypothalamus (PVN). METHODS: We used spontaneous hypertensive rats (SHRs) as animal model rats. Micro osmotic pump was used to give capsaicin through PVN for 28 days, starting from age12-week-old. RESULTS: The results showed that capsaicin significantly reduced blood pressure from the 16th day of infusion onward. At the end of the experimental period, we measured cardiac hypertrophy index and the heart rate (HR), and the results showed that the cardiac hypertrophy and heart rate of rats was significantly improved upon capsaicin chronic infusion. Norepinephrine (NE) and epinephrine (EPI) in plasma of SHRs treated with capsaicin were also decreased. Additionally, capsaicin increased the protein expression and number of positive cells of SIRT1 and the 67-kDa isoform of glutamate decarboxylase (GAD67), decreased the production of reactive oxygen species (ROS), number of positive cells of NOX2, those of Angiotensin Converting Enzyme (ACE) and p-IKKß, tyrosine hydroxylase (TH), the gene expression levels of NOX4 and pro-inflammatory cytokines. Capsaicin also decreased the relative protein expressions of protein in MAPKs pathway. CONCLUSION: Current data indicated that capsaicin within the PVN improves hypertension and cardiac hypertrophy via SIRT1/NF-κB/MAPKs pathway in the PVN of SHRs, supporting its potential as candidate drug for preventing and improving hypertension.

A Novel 450 nm Semiconductor Blue Laser System for Application in Colon Endoscopic Surgery: An Ex Vivo Study of Laser-Tissue Interactions.

Objective: Our study aimed to detect whether 450 nm blue laser can be applied effectively and safely in endosocopic submucosal dissection (ESD) system for surgery in colonic tissue. Background data: Semiconductor blue laser has been applied in surgery due to its excellent cutting property, however, whether blue laser can be applied in colonic surgery has not been reported. Materials and methods: Porcine colon tissues were vaporized by 450 nm blue semiconductor laser at 10-25 W and at working distances from 0.5 to 3 mm, with a three-dimensional scanning system. Moreover, we designed an ESD model and applied blue laser at 10 W on porcine colonic tissues with this system. Dimensions of the vaporized tissues and coagulation zones were assessed under microscopy. Results: Since the thickness of colonic wall is no more than 1 mm, first we determined the cutting property and safety of blue laser on porcine colon tissue and found that blue laser at 10 W made lesions shallower than 1 mm and the depth of vaporization can be controlled effectively within muscularis mucosa and submucosa. Moreover, a large scale of porcine colonic tissue was vaporized precisely by blue laser at power of 10 W with the ESD system ex vivo. Conclusions: Our results indicate that 450 nm blue laser at 10 W can be well controlled for laser-tissue interaction with excellent cutting efficiency and less thermal damage in adjacent tissues especially side of the submucosa. Therefore, 450 nm semiconductor blue laser could be a safe alternative approach for colonic surgery.

A novel 450-nm blue laser system for surgical applications: efficacy of specific laser-tissue interactions in bladder soft tissue.

Low-power blue laser allows clean cutting with little bleeding and no undesired coagulations in adjacent tissues; however, studies on high-power blue laser soft tissue ablation properties, including vaporization and coagulation, have not been reported yet. The purpose of this study is to evaluate and analyze the ablation efficacy and coagulation properties of bladder epithelium tissues with a 30-W 450-nm wavelength blue laser. Well-designed ex vivo experiments compared blue laser and 532-nm LBO green laser, both with laser power up to 30 W, for porcine bladder tissue vaporization and coagulation at different experimental parameter settings. At working distance of 1 mm and sweeping speed of 1.5 mm/s, the vaporization efficiency of blue laser and green laser was 5.14mm3/s and 1.20mm3/s, while the depth of coagulation layer was 460 ± 70 µm and 470 ± 80 µm, respectively. We found both blue laser and green laser have excellent efficacy of tissue vaporization and similar tissue coagulation properties. Moreover, in a set of in vivo experiments simulated laser transurethral resection (TUR) surgery on dogs, we found both blue laser and green laser exhibited similar and satisfactory vaporization and coagulation outcomes. Taken together, our results demonstrate that a 450-nm wavelength high-power diode blue laser, like 532-nm wavelength green laser, is capable to produce high efficient tissue vaporization, low-laser tissue penetration, good tissue coagulation, and has low thermal damage to adjacent tissues. Therefore, a 30-W blue diode laser could be a new and safe alternative for surgeries of superficial bladder diseases.