title: Tumour necrosis factor-alpha participates on the endothelin-1/nitric oxide imbalance in small arteries from obese patients: role of perivascular adipose tissue.
abstract: OBJECTIVE
  We assessed the impact of vascular and perivascular tumour necrosis factor-alpha (TNF-α) on the endothelin (ET)-1/nitric oxide (NO) system and the molecular pathways involved in small arteries from visceral fat of obese patients (Obese) and Controls.
  
  
  RESULTS
  Isolated small arteries from 16 Obese and 14 Controls were evaluated on a pressurized micromyograph. Endogenous ET-1 activity was assessed by the ETA blocker BQ-123. TNF-α and NO were tested by anti-TNF-α infliximab (IFX) and N(ω)-nitro-l-arginine methylester (L-NAME). Gene and protein expression of TNF-α, ET-1, ETA, and ETB receptors were determined by RT-PCR and IHC on arterial wall and in isolated adipocytes. Obese showed a blunted L-NAME-induced vasoconstriction, which was potentiated by IFX, and an increased relaxation to BQ-123, unaffected by L-NAME but attenuated by IFX. Perivascular adipose tissue (PVAT) removal reversed these effects. Obese showed intravascular superoxide excess, which was decreased by apocynin (NAD(P)H oxidase inhibitor), L-NAME, and BQ-123 incubations, and abolished by IFX. An increased vascular expression of ET-1, ETA, and ETB receptors, and higher vascular/perivascular TNF-α and TNF-α receptor expression were also detected. The arterial expression and phosphorylation of c-Jun N-terminal kinase (JNK) were higher in Obese vs. Controls, and downregulated by IFX.
  
  
  CONCLUSIONS
  In small arteries of Obese, PVAT-derived TNF-α excess, and an increased vascular expression of ET-1 and ETA receptor, contribute to the ET-1/NO system imbalance, by impairing tonic NO release. Reactive oxygen species excess, via NAD(P)H oxidase activation, induces the endothelial nitric oxide synthase uncoupling, which in turn generates superoxide and impairs NO production. The up-regulated JNK pathway represents a crucial molecular signalling involved in this process.
authors.affiliation: Department of Clinical and Experimental Medicine, University of Pisa, Via Roma, 67, 56100 Pisa, Italy agostino.virdis@med.unipi.it.
authors.forename: Agostino
authors.initials: A
authors.lastname: Virdis
authors.affiliation: Department of Clinical and Experimental Medicine, University of Pisa, Via Roma, 67, 56100 Pisa, Italy.
authors.forename: Emiliano
authors.initials: E
authors.lastname: Duranti
authors.affiliation: Department of Clinical and Experimental Medicine, University of Pisa, Via Roma, 67, 56100 Pisa, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Rossi
authors.affiliation: Department of Clinical and Experimental Medicine, University of Pisa, Via Roma, 67, 56100 Pisa, Italy.
authors.forename: Umberto
authors.initials: U
authors.lastname: Dell'Agnello
authors.affiliation: Department of Clinical and Experimental Medicine, University of Pisa, Via Roma, 67, 56100 Pisa, Italy.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Santini
authors.affiliation: Surgery Unit IV, University Hospital of Pisa, Pisa, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Anselmino
authors.affiliation: Department of Surgery, Medical, Molecular, and Critical Area Pathology, University of Pisa, Pisa, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Chiarugi
authors.affiliation: Department of Clinical and Experimental Medicine, University of Pisa, Via Roma, 67, 56100 Pisa, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Taddei
authors.affiliation: Department of Clinical and Experimental Medicine, University of Pisa, Via Roma, 67, 56100 Pisa, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Solini
mesh_terms: D016022:Case-Control Studies; D002478:Cells, Cultured; D065130:Endothelin A Receptor Antagonists / Q000494:pharmacology; D065128:Endothelin Receptor Antagonists / Q000494:pharmacology; D019332:Endothelin-1 / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D000069285:Infliximab / Q000494:pharmacology; D050152:Intra-Abdominal Fat / Q000378:metabolism / Q000502:physiology*; D008297:Male; D055806:Microvessels / Q000502:physiology; D008875:Middle Aged; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D009767:Obesity, Morbid / Q000503:physiopathology*; D010456:Peptides, Cyclic / Q000494:pharmacology; D044022:Receptor, Endothelin A / Q000187:drug effects; D018124:Receptors, Tumor Necrosis Factor / Q000037:antagonists & inhibitors; D013481:Superoxides / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology*; D014661:Vasoconstriction / Q000187:drug effects
chemical_list: D065130:Endothelin A Receptor Antagonists; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1; D004791:Enzyme Inhibitors; D010456:Peptides, Cyclic; D044022:Receptor, Endothelin A; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha; D013481:Superoxides; D009569:Nitric Oxide; D000069285:Infliximab; C072247:cyclo(Trp-Asp-Pro-Val-Leu); D019331:NG-Nitroarginine Methyl Ester
keywords: Endothelin-1; Nitric oxide; Perivascular adipose tissue; Small vessels; TNF-α