Pelargonic acid vanillylamide alleviates hepatic autophagy and ER stress in hepatic steatosis model.

Pelargonic acid vanillylamide (PAVA) has been shown to reduce hepatic lipid accumulation in an obese rat model, however the underlying mechanism responsible for regulating lipid metabolism remains unclear. This study investigated the molecular mechanisms invoked by PAVA in regulating lipogenesis, autophagy, and endoplasmic reticulum (ER) stress in obese rats. Male Sprague-Dawley rats were fed on a diet consisting of 65.26% fat (16 weeks) and HepG2 cells were incubated with 200 µM oleic acid (OA) plus 100 µM palmitic acid (PA) for 48 h. These treatments resulted in a steatosis model. PAVA was shown to reduce fat deposition in hepatocytes in HepG2 by reducing lipotoxicity, the triglyceride content, the expression of sterol regulatory element binding protein 1c (SREBP-1c) and fatty acid synthase (FASN). PAVA also significantly reduced the calcium level and the expression of calpain 2 and upregulated the expression of Atg7 in comparison to the HFD group. In addition, PAVA was shown to significantly decrease the expression of autophagy pathway-related proteins including LC3 and p62. Treatment with PAVA (1 mg/day) reduced the expressions of ER stress markers Bip, ATF6 (p50), p-IRE1/IRE1, p-eIF2α/eIF2α, pJNK, CHOP and cleaved CASP12. In conclusion, PAVA ameliorated obesity induced hepatic steatosis by attenuating defective autophagy and ER stress pathways.

The capsaicinoid nonivamide suppresses the inflammatory response and attenuates the progression of steatosis in a NAFLD-rat model.

Nonalcoholic fatty liver disease (NAFLD) is relatively associated with comorbidities in obesity and metabolic inflammation. Low-grade inflammation following the high-fat diet (HFD)-induced NAFLD can promote the development of nonalcoholic steatohepatitis (NASH) through particularly liver-resident immune cell recruitment and hepatic nuclear factor kappa B (NF-κB) pathway. Therefore, inflammatory intervention may contribute to NASH reduction. Pelargonic acid vanillylamide (PAVA) or nonivamide is one of the pungent capsaicinoids of Capsicum species and has been found in chili peppers. Our previous study demonstrated that PAVA improved hepatic function, decreased oxidative stress and reduced apoptotic cell death but the insight role of PAVA on NAFLD is still unclear. Thus, this study aimed to investigate the underlying anti-inflammatory mechanism of PAVA in an NAFLD-rat model. Male Sprague Dawley rats were fed with normal diet or HFD for 16 weeks. Then high-fat rats were given vehicle or PAVA (1 mg/kg/day) for another 4 weeks. We found that PAVA alleviated hepatic inflammation associated with the reducing toll-like receptor 4/NF-κB pathway, showing significantly lower recruitment of cluster of differentiation 44. PAVA also maintained activity of insulin signaling pathway, and attenuated NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome formation. NAFLD progresses to NASH through transforming growth factor (TGF-ß1), and also recovery to simple stage followed by PAVA suppresses pro-inflammatory cytokines such as tumor necrosis factor-α, interleukin-1ß, interleukin-6, and Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway. Therefore, our findings suggest that PAVA provides a novel therapeutic approach for NAFLD and slows the progression to NASH.

Pelargonic acid vanillylamide and rosuvastatin protect against oxidized low-density lipoprotein-induced endothelial dysfunction by inhibiting the NF-κB/NLRP3 pathway and improving cell-cell junctions.

Oxidized low-density lipoprotein (ox-LDL) not only causes hyperlipidemia and contributes to atherosclerosis but also induces the endothelial dysfunction that leads to cardiovascular diseases. The nuclear factor-kappa B (NF-κB) pathway plays a key role in many chronic disorders and is a transcriptional factor in various inflammatory responses. The present study aimed to investigate the synergistic effects of pelargonic acid vanillylamide (PAVA) and rosuvastatin (RSV) on ox-LDL-induced inflammatory responses in human vascular endothelial cells (HUV-EC-C). HUV-EC-C were pretreated with PAVA or RSV and their combination for 2 h followed by ox-LDL for 24 h. The MTT assay was used to measure mitochondrial function. The DCFH-DA assay was used to evaluate oxidative phosphorylation, and western blotting was used to measured NF-κB/NLRP3 and related signaling pathways in HUV-EC-C. Ox-LDL induced lectin-type oxidized LDL receptor 1 (LOX-1) expression, NADPH oxidase 4 activation, and the overexpression of reactive oxygen species, which were inhibited by pretreatment with the combination of PAVA and RSV. Moreover, PAVA and RSV inhibited ox-LDL-induced NF-κBp65 activation. Ox-LDL induced NF-κB/NLRP3 pathway activation by inducing C-reactive protein expression, NLRP3 activation, caspase-1 activation, and IL-1ß secretion, which were inhibited by pretreatment with the combination of PAVA and RSV. The combination of PAVA and RSV reduced ox-LDL-induced recruitment of monocytes to the site of inflammation, inhibited activation of the NLRP3 inflammasome, and ameliorated the impairment of cell-cell junctions through the NF-κB pathway. Our results suggest that the synergistic effects of PAVA and RSV provide a novel mechanism for the treatment of cardiovascular diseases.

Capsaicinoid nonivamide improves nonalcoholic fatty liver disease in rats fed a high-fat diet.

Nonalcoholic fatty liver disease (NAFLD) is a chronic disease that causes morbidity associated with metabolic syndrome. NAFLD is a worldwide problem and represents a major cause of liver injury, which can lead to liver cell death. We investigated the effects of nonivamide (pelargonic acid vanillylamide, PAVA; 1 mg/kg) and rosuvastatin (RSV; 10 mg/kg) on hepatic steatosis induced by a high-fat diet (HFD). Male Sprague-Dawley rats were fed a HFD for 16 weeks then received PAVA or RSV for 4 additional weeks. We examined the metabolic parameters, function, fat content, histological alterations, reactive oxygen species production, and apoptotic cell death of the liver, in addition to the expression of the following important molecules: transient receptor potential cation channel subfamily V member 1 (TRPV1) phosphorylation of sterol regulatory element binding protein (pSREBP-1c/SREBP-1c), total and membrane glucose transporter 2 (GLUT2), 4-hydroxynonenal (4-HNE), and cleaved caspase-3. HFD-induced hepatic steatosis was associated with significantly increased morphological disorganization, injury markers, oxidative stress, lipid peroxidation, and apoptosis. However, metabolic dysfunction and hepatic injury were reduced by RSV and PAVA treatment. PAVA regulated lipid deposition, improved insulin resistance, and decreased oxidative stress and apoptotic cell death. Therefore, PAVA represents a promising therapeutic approach for treating metabolic disorders in patients with NAFLD.

Synergistic effects of the capsaicinoid nonivamide and rosuvastatin on obesity-related endothelial dysfunction in rat fed a high-fat diet.

Capsaicinoid nonivamide (PAVA) and rosuvastatin (RSV) have been shown to exert antioxidant and anti-obesity effects in various animal models, but it is unknown whether their combination would be an effective treatment for obesity-related endothelial dysfunction. This study aimed to investigate the mechanism of PAVA in synergy with RSV. Male Sprague-Dawley rats were given a high-fat diet (HFD) or normal diet during a 20-week period. At 16 weeks, rats in each diet group were divided into subgroups. Normal diet rats were divided into Normal diet control, Normal diet with PAVA, and Normal diet with RSV groups. HFD rats were subdivided into HFD control, HFD with PAVA, HFD with RSV, and HFD with PAVA + RSV groups and evaluated for metabolic parameters, blood pressure, aortic function, and histological change of the aorta in rats. Our results showed the combined therapy had a significantly greater effect than the monotherapy in all measured parameters; this was indicated by improvement in insulin sensitivity and aortic function, decreased blood pressure, lower oxidative stress, and prevention of vascular damage. The synergistic effect of the PAVA and RSV can protect HFD-induced obesity-related endothelial dysfunction, suggesting that the combination of PAVA and RSV could be an effective alternative treatment for obesity-related complications in patients with cardiovascular disease.