scholarly journals Acetate intolerance is mediated by enhanced synthesis of nitric oxide by endothelial cells.

1997 ◽  
Vol 8 (9) ◽  
pp. 1431-1436 ◽  
Author(s):  
A Amore ◽  
P Cirina ◽  
S Mitola ◽  
L Peruzzi ◽  
R Bonaudo ◽  
...  

The clinical picture of acetate intolerance strictly mimics the nitric oxide (NO) effect, including smooth muscle relaxation and extreme vasodilation. Because acetate induces production of cAMP, which is a powerful stimulus of NO synthase (NOS), we evaluated the effect of different dialysate solutions with and without acetate on NOS activity in endothelial cells (EC). NOS activity of EC, evaluated as H3-citrulline produced from H3-arginine, was modulated by the dialysate composition (e.g., 38 mmol/L acetate produced an increase of 3.2 +/- 0.39-fold compared with basal values (P < 0.0005), and the small amount of acetate (4 mmol/L) in 35 mmol/L bicarbonate solution increased the NOS activity by 2 +/- 0.49-fold (P < 0.05). Conversely, the acetate-free solution produced no effect on NOS activity. The mRNA encoding for inducible NOS was highly expressed in EC incubated with acetate buffer and also with acetate in bicarbonate dialysis buffer. The EC proliferative index was depressed by acetate (P < 0.0005), and tumor necrosis factor synthesis was increased (P < 0.0005) compared with acetate-free buffer. This study suggests that dialytic "acetate intolerance" can be induced by the activation, through cAMP and tumor necrosis factor release, of NOS. The small amount of acetate in bicarbonate dialysate, although capable of inducing in vitro NOS activation, is likely to be rapidly metabolized, whereas the large amounts of this anion in acetate fluids overwhelm metabolism by the liver. Acetate-free dialysate is the only solution that provides an acceptable level of biocompatibility both in vivo and in vitro.

Life Sciences ◽  
1996 ◽  
Vol 59 (13) ◽  
pp. PL207-PL211 ◽  
Author(s):  
Teresa Iuvone ◽  
Fulvio D'Acquisto ◽  
Rosa Carnuccio ◽  
Massimo Di Rosa

Planta Medica ◽  
2017 ◽  
Vol 83 (09) ◽  
pp. 770-777 ◽  
Author(s):  
Franciane Marques ◽  
Maycow da Costa ◽  
Cátia Vittorazzi ◽  
Luciane Gramma ◽  
Thiago Barth ◽  
...  

Abstract Struthanthus vulgaris is probably the most common medicinal mistletoe plant in Brazil, and has been used in folk medicine as an anti-inflammatory agent and for cleaning skin wounds. Our proposal was to evaluate the anti-inflammatory activity of S. vulgaris ethanol leaf extract and provide further insights of how this biological action could be explained using in vitro and in vivo assays. In vitro anti-inflammatory activity was preliminarily investigated in lipopolysaccharide/interferon gamma-stimulated macrophages based on their ability to inhibit nitric oxide production and tumor necrosis factor-alpha. In vivo anti-inflammatory activity of S. vulgaris ethanol leaf extract was investigated in the mice carrageenan-induced inflammation air pouch model. The air pouches were inoculated with carrageenan and then treated with 50 and 100 mg/kg of S. vulgaris ethanol leaf extract or 1 mg/kg of dexamethasone. Effects on the immune cell infiltrates, pro- and anti-inflammatory mediators such as tumor necrosis factor-alpha, interleukin 1, interleukin 10, and nitric oxide, were evaluated. The chemical composition of S. vulgaris ethanol leaf extract was characterized by LC-MS/MS. In vitro S. vulgaris ethanol leaf extract significantly decreased the production of nitric oxide and tumor necrosis factor-alpha in macrophages and did not reveal any cytotoxicity. In vivo, S. vulgaris ethanol leaf extract significantly suppressed the influx of leukocytes, mainly neutrophils, protein exudation, nitric oxide, tumor necrosis factor-alpha, and interleukin 1 concentrations in the carrageenan-induced inflammation air pouch. In conclusion, S. vulgaris ethanol leaf extract exhibited prominent anti-inflammatory effects, thereby endorsing its usefulness as a medicinal therapy against inflammatory diseases, and suggesting that S. vulgaris ethanol leaf extract may be a source for the discovery of novel anti-inflammatory agents.


2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Aman Gupta ◽  
Divay Chandra ◽  
Yingze Zhang ◽  
Steven Reis ◽  
Frank Sciurba

Rationale: There is significant in vitro evidence demonstrating anti-atherogenic effect of circulating Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL). Also, decreased circulating TRAIL levels have been reported in patients with acute myocardial infarction and in those undergoing coronary catheterization due to suspected coronary atherosclerosis. However, it remains unknown if TRAIL levels are associated with sub-clinical coronary atherosclerosis. Methods: The study included 460 current and former smokers enrolled in the Pittsburgh COPD SCCOR study. Serum TRAIL levels were measured by electrochemiluminescence immunoassay, according to the manufacture’s protocol (Meso Scale Discovery, Gaithersburg, Maryland). Coronary atherosclerosis was assessed by a validated visual coronary artery calcium scoring system using non-EKG gated chest CT scans (Weston score). Ordinal logistic regression models were used to identify significant associations between categories of CAC score (0, 1-3, 4-8, and 9-12) and TRAIL level, and to adjust for cardiovascular risk factors. Results: The mean age of the 460 participants was 65.7 ± 6.3 years, 52.2% were male, and the mean pack years of smoking was 55.0 ± 30.8 years. In univariate analyses, each standard deviation decrease in TRAIL levels was associated with 1.42-fold increase in the odds of having calcium scores in one higher category (p<0.001). This association persisted despite adjustment for age, gender, race, body mass index, hypertension, diabetes, hyperlipidemia, pack years of smoking, and current smoking status (adjusted OR for higher category of calcium score per SD decrease in TRAIL level 1.22, p=0.04). Conclusions: Our results expand on the in vitro and in vivo data linking decreased TRAIL levels with increased atherosclerosis by demonstrating a novel association between lower circulating TRAIL and increased subclinical coronary atherosclerosis.


Endocrinology ◽  
1998 ◽  
Vol 139 (5) ◽  
pp. 2278-2283 ◽  
Author(s):  
Brian N. Finck ◽  
Keith W. Kelley ◽  
Robert Dantzer ◽  
Rodney W. Johnson

1994 ◽  
Vol 266 (6) ◽  
pp. H2535-H2541 ◽  
Author(s):  
P. Wang ◽  
Z. F. Ba ◽  
I. H. Chaudry

Although depressed endothelium-dependent relaxation occurs during early sepsis, the precise mechanism responsible for this remains unknown. Because the elevated levels of plasma tumor necrosis factor (TNF) play a major role in the pathophysiology of sepsis, we investigated whether TNF-alpha administration alters endothelium-dependent relaxation. To study this, recombinant TNF-alpha (1.2 x 10(7) U/mg) was infused intravenously (0.25 mg/kg body wt) for 0.5 h in normal rats, and mean arterial pressure was monitored. At 1 h after the completion of TNF-alpha or vehicle infusion, the aorta and a pulmonary artery were isolated, cut into 2.5-mm rings, and placed in organ chambers. Norepinephrine (2 x 10(-7) M) was applied to achieve near-maximal contraction, and dose responses for an endothelium-dependent vasodilator, acetylcholine, and an endothelium-independent vasodilator, nitroglycerine, were determined. In additional studies, aortic rings from normal animals were incubated with TNF-alpha for 2 h in vitro, and vascular reactivity was determined. The results indicate that TNF-alpha administration significantly reduced acetylcholine-induced vascular relaxation both in vivo and in vitro. Such a reduction was sustained at least 80 min after the completion of 2-h incubation with TNF-alpha. In contrast, TNF did not alter nitroglycerine-induced vascular relaxation. Thus TNF-alpha depresses endothelium-dependent relaxation in vitro as well as in vivo. Because TNF-alpha infusion increases plasma TNF levels without decreasing mean arterial pressure, the depressed endothelium-dependent relaxation observed during early sepsis may be due to the elevated circulating levels of TNF.


Blood ◽  
1990 ◽  
Vol 76 (5) ◽  
pp. 1046-1053 ◽  
Author(s):  
AS Duncombe ◽  
A Meager ◽  
HG Prentice ◽  
JE Grundy ◽  
HE Heslop ◽  
...  

Abstract After bone marrow transplantation (BMT), mortality from viral infections such as cytomegalovirus (CMV) remains high. Gamma-Interferon (gamma IFN) and tumor necrosis factor (TNF) are produced constitutively after BMT and have anti-viral properties. To study the effects of these cytokines on CMV interaction with host cells, we have used patient marrow fibroblasts since marrow stroma is a target for CMV infection correlating with myelosuppression in vivo. Both gamma IFN and TNF are constitutively produced by recipient CD3+ and CD16+ lymphocytes, but not by their marrow fibroblasts. Secretion by peripheral blood mononuclear cells is increased if they are cultured with host fibroblasts infected with CMV in vitro and the levels of gamma IFN and TNF produced are within the range that protects fresh fibroblasts from CMV infection. Constitutive secretion of cytokines by lymphocytes declines by 8 weeks after BMT, a time when the risk of CMV disease increases sharply. The in vitro phenomenon that we have described needs to be evaluated in correlative studies on individual BMT recipients to determine whether such a cytokine-mediated defense mechanism against CMV may operate in vivo.


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