TRPV1 Activation Attenuates High-Salt Diet-Induced Cardiac Hypertrophy and Fibrosis through PPAR- δ

High-salt diet-induced cardiac hypertrophy and fibrosis are associated with increased reactive oxygen species production. Transient receptor potential vanilloid type 1 (TRPV1), a specific receptor for capsaicin, exerts a protective role in cardiac remodeling that resulted from myocardial infarction, and peroxisome proliferation-activated receptors δ (PPAR-δ) play an important role in metabolic myocardium remodeling. However, it remains unknown whether activation of TRPV1 could alleviate cardiac hypertrophy and fibrosis and the effect of cross-talk between TRPV1 and PPAR-δ on suppressing high-salt diet-generated oxidative stress. In this study, high-salt diet-induced cardiac hypertrophy and fibrosis are characterized by significant enhancement of HW/BW%, LVEDD, and LVESD, decreased FS and EF, and increased collagen deposition. These alterations were associated with downregulation of PPAR-δ, UCP2 expression, upregulation of iNOS production, and increased oxidative/nitrotyrosine stress. These adverse effects of long-term high-salt diet were attenuated by chronic treatment with capsaicin. However, this effect of capsaicin was absent in TRPV1−/− mice on a high-salt diet. Our finding suggests that chronic dietary capsaicin consumption attenuates long-term high-salt diet-induced cardiac hypertrophy and fibrosis. This benefit effect is likely to be caused by TRPV1 mediated upregulation of PPAR-δ expression

Caffeine intake antagonizes salt sensitive hypertension through improvement of renal sodium handling

High salt intake is a major risk factor for hypertension. Although acute caffeine intake produces moderate diuresis and natriuresis, caffeine increases the blood pressure (BP) through activating sympathetic activity. However, the long-term effects of caffeine on urinary sodium excretion and blood pressure are rarely investigated. Here, we investigated whether chronic caffeine administration antagonizes salt sensitive hypertension by promoting urinary sodium excretion. Dahl salt-sensitive (Dahl-S) rats were fed with high salt diet with or without 0.1% caffeine in drinking water for 15 days. The BP, heart rate and locomotor activity of rats was analyzed and urinary sodium excretion was determined. The renal epithelial Na+ channel (ENaC) expression and function were measured by in vivo and in vitro experiments. Chronic consumption of caffeine attenuates hypertension induced by high salt without affecting sympathetic nerve activity in Dahl-S rats. The renal α-ENaC expression and ENaC activity of rats decreased after chronic caffeine administration. Caffeine increased phosphorylation of AMPK and decrease α-ENaC expression in cortical collecting duct cells. Inhibiting AMPK abolished the effect of caffeine on α-ENaC. Chronic caffeine intake prevented the development of salt-sensitive hypertension through promoting urinary sodium excretion, which was associated with activation of renal AMPK and inhibition of renal tubular ENaC

Stimulation of Intestinal Cl- Secretion Through CFTR by Caffeine Intake in Salt-Sensitive Hypertensive Rats

Background/Aims: High salt consumption is a major risk factor for hypertension, and sodium homeostasis is regulated by both intestinal sodium absorption and urinary sodium excretion. Chronic caffeine intake has been reported to attenuate salt-sensitive hypertension by promoting urinary sodium excretion; however, its exact role in intestinal sodium absorption remains unknown. Here, we investigated whether and how chronic caffeine consumption antagonizes salt-sensitive hypertension by inhibiting intestinal sodium absorption. Methods: Dahl salt-sensitive rats were fed 8% NaCl chow and 0.1% caffeine in their drinking water for 15 days. The blood pressure and fecal sodium content were measured. The effect of caffeine on the movement of Cl- in enterocyte cells was determined with the Ussing chamber assay. Results: Rats that were treated with caffeine displayed significantly lower mean blood pressure and higher fecal sodium content than the controls. Consistent with these findings, caffeine intake decreased fluid absorption by the intestine in the fluid perfusion experiment. Further, the results from the Ussing chamber assay indicated that caffeine promoted Cl- secretion through enterocyte apical cystic fibrosis transmembrane conductance regulator (CFTR), and thus inhibited sodium absorption. Moreover, depletion of cAMP or inhibition of CFTR completely abolished the effect of caffeine on Cl- secretion. Conclusion: The results indicate that chronic caffeine consumption reduces sodium absorption by promoting CFTR-mediated Cl- secretion in the intestine, which contributes to the anti-hypertensive effect of caffeine in salt-sensitive rats

Deficiency of PKD2L1 (TRPP3) Exacerbates Pathological Cardiac Hypertrophy by Augmenting NCX1-Mediated Mitochondrial Calcium Overload

Summary: High salt intake is one independent risk factor for cardiac hypertrophy. Polycystic kidney disease 2-like 1 (PKD2L1, also called TRPP3) acts as a sour sensor in taste cells, and its possible role in the cardiovascular system is unknown. Here, we report that knockout of PKD2L1 exacerbated high-salt diet (HSD)-induced cardiac hypertrophy and fibrosis, accompanied by cardiac dysfunction and reduced cardiac mitochondrial oxidative phosphorylation and enzyme activity. Furthermore, knockdown of PKD2L1 led to more serious mitochondrial Ca2+ overload and reduced Ca2+ uptake in cardiomyocytes on high salt loading. Mechanistically, PKD2L1 deficiency increased p300-mediated acetylation of histone 3 lysine 27 on the promoter of sodium/calcium exchange 1 (NCX1) by repressing AMP-activated protein kinase (AMPK) activity, resulting in NCX1 overexpression and mitochondrial Ca2+ overload. These results reveal an inhibitory effect of PKD2L1 on cardiac hypertrophy and provide a mechanistic insight into the link between mitochondrial Ca2+ homeostasis and cardiac hypertrophy. : Lu et al. reveal a role of a mitochondria-localized TRPP member, PKD2L1, in high salt-induced cardiac hypertrophy. PKD2L1 knockout leads to overexpression of NCX1 through increasing the acetylation level of histone 3 lysine 27 on NCX1 promoter and thus exacerbates mitochondrial calcium overload by activating the reverse mode of NCX1 in cardiomyocytes. Keywords: high-salt diet, cardiac hypertrophy, PKD2L1, mitochondria, NCX

Sodium‐Glucose Cotransporter 2 Inhibitor Canagliflozin Antagonizes Salt‐Sensitive Hypertension Through Modifying Transient Receptor Potential Channels 3 Mediated Vascular Calcium Handling

Background Salt‐sensitive hypertension is highly prevalent and associated with cardiorenal damage. Large clinical trials have demonstrated that SGLT2 (sodium‐glucose cotransporter 2) inhibitors exert hypotensive effect and cardiorenal protective benefits in patients with hypertension with and without diabetes. However, the underlying mechanism remains elusive. Methods and Results Dahl salt‐sensitive rats and salt‐insensitive controls were fed with 8% high‐salt diet and some of them were treated with canagliflozin. The blood pressure, urinary sodium excretion, and vascular function were detected. Transient receptor potential channel 3 (TRPC3) knockout mice were used to explain the mechanism. Canagliflozin treatment significantly reduced high‐salt‐induced hypertension and this effect was not totally dependent on urinary sodium excretion in salt‐sensitive hypertensive rats. Assay of vascular function and proteomics showed that canagliflozin significantly inhibited vascular cytoplasmic calcium increase and vasoconstriction in response to high‐salt diet. High salt intake increased vascular expression of TRPC3 in salt‐sensitive rats, which could be alleviated by canagliflozin treatment. Overexpression of TRPC3 mimicked salt‐induced vascular cytosolic calcium increase in vitro and knockout of TRPC3 erased the antihypertensive effect of canagliflozin. Mechanistically, high‐salt‐induced activation of NCX1 (sodium‐calcium exchanger 1) reverse mode increased cytoplasmic calcium level and vasoconstriction, which required TRPC3, and this process could be blocked by canagliflozin. Conclusions We define a previously unrecognized role of TRPC3/NCX1 mediated vascular calcium dysfunction in the development of high‐salt‐induced hypertension, which can be improved by canagliflozin treatment. This pathway is potentially a novel therapeutic target to antagonize salt‐sensitive hypertension

Effect of electroacupuncture on urinary leakage among women with stress urinary incontinence: A randomized clinical trial

© 2017 American Medical Association. All rights reserved. IMPORTANCE: Electroacupuncture involving the lumbosacral region may be effective for women with stress urinary incontinence (SUI), but evidence is limited. OBJECTIVE: To assess the effect of electroacupuncture vs sham electroacupuncture for women with SUI. DESIGN, SETTING, AND PARTICIPANTS: Multicenter, randomized clinical trial conducted at 12 hospitals in China and enrolling 504 women with SUI between October 2013 and May 2015, with data collection completed in December 2015. INTERVENTIONS: Participants were randomly assigned (1:1) to receive 18 sessions (over 6 weeks) of electroacupuncture involving the lumbosacral region (n = 252) or sham electroacupuncture (n = 252) with no skin penetration on sham acupoints. MAIN OUTCOMES AND MEASURES: The primary outcome was change from baseline to week 6 in the amount of urine leakage, measured by the 1-hour pad test. Secondary outcomes included mean 72-hour urinary incontinence episodes measured by a 72-hour bladder diary (72-hour incontinence episodes). RESULTS: Among the 504 randomized participants (mean [SD] age, 55.3 [8.4] years), 482 completed the study. Mean urine leakage at baseline was 18.4 g for the electroacupuncture group and 19.1 g for the sham electroacupuncture group. Mean 72-hour incontinence episodes were 7.9 for the electroacupuncture group and 7.7 for the sham electroacupuncture group. At week 6, the electroacupuncture group had greater decrease in mean urine leakage (-9.9 g) than the sham electroacupuncture group (-2.6 g) with a mean difference of 7.4 g (95% CI, 4.8 to 10.0; P \u3c .001). During some time periods, the change in the mean 72-hour incontinence episodes from baseline was greater with electroacupuncture than sham electroacupuncture with between-group differences of 1.0 episode in weeks 1 to 6 (95% CI, 0.2-1.7; P = .01), 2.0 episodes in weeks 15 to 18 (95% CI, 1.3-2.7; P \u3c .001), and 2.1 episodes in weeks 27 to 30 (95% CI, 1.3-2.8; P \u3c .001). The incidence of treatment-related adverse events was 1.6% in the electroacupuncture group and 2.0% in the sham electroacupuncture group, and all events were classified as mild. CONCLUSIONS AND RELEVANCE: Among women with stress urinary incontinence, treatment with electroacupuncture involving the lumbosacral region, compared with sham electroacupuncture, resulted in less urine leakage after 6 weeks. Further research is needed to understand long-term efficacy and the mechanism of action of this intervention. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01784172