Hyperhomocysteinemia potentiates diabetes-impaired EDHF-induced vascular relaxation: Role of insufficient hydrogen sulfide

Zhongjian Cheng, Xinggui Shen, Xiaohua Jiang, Huimin Shan, Maria Cimini, Pu Fang, Yong Ji, Joon Young Park, Konstantinos Drosatos, Xiaofeng Yang, Christopher G Kevil, Raj Kishore, Hong Wang

Research output: Contribution to journalArticlepeer-review

39 Scopus citations

Abstract

UNLABELLED: Insufficient hydrogen sulfide (H2S) has been implicated in Type 2 diabetic mellitus (T2DM) and hyperhomocysteinemia (HHcy)-related cardiovascular complications. We investigated the role of H2S in T2DM and HHcy-induced endothelial dysfunction in small mesenteric artery (SMA) of db/db mice fed a high methionine (HM) diet. HM diet (8 weeks) induced HHcy in both T2DM db/db mice and non-diabetic db/+ mice (total plasma Hcy: 48.4 and 31.3 µM, respectively), and aggravated the impaired endothelium-derived hyperpolarization factor (EDHF)-induced endothelium-dependent relaxation to acetylcholine (ACh), determined by the presence of eNOS inhibitor N(ω)-nitro-L-arginine methyl ester (L-NAME) and prostacyclin (PGI2) inhibitor indomethacin (INDO), in SMA from db/db mice but not that from db/+ mice. A non-selective Ca2+-active potassium channel (KCa) opener NS309 rescued T2DM/HHcy-impaired EDHF-mediated vascular relaxation to ACh. EDHF-induced relaxation to ACh was inhibited by a non-selective KCa blocker TEA and intermediate-conductance KCa blocker (IKCa) Tram-34, but not by small-conductance KCa (SKCa) blocker Apamin. HHcy potentiated the reduction of free sulfide, H2S and cystathionine γ-lyase protein, which converts L-cysteine to H2S, in SMA of db/db mice. Importantly, a stable H2S donor DATS diminished the enhanced O2- production in SMAs and lung endothelial cells of T2DM/HHcy mice. Antioxidant PEG-SOD and DATS improved T2DM/HHcy impaired relaxation to ACh. Moreover, HHcy increased hyperglycemia-induced IKCa tyrosine nitration in human micro-vascular endothelial cells. EDHF-induced vascular relaxation to L-cysteine was not altered, whereas such relaxation to NaHS was potentiated by HHcy in SMA of db/db mice which was abolished by ATP-sensitive potassium channel blocker Glycolamide but not by KCa blockers.

CONCLUSIONS: Intermediate HHcy potentiated H2S reduction via CSE-downregulation in microvasculature of T2DM mice. H2S is justified as an EDHF. Insufficient H2S impaired EDHF-induced vascular relaxation via oxidative stress and IKCa inactivation in T2DM/HHcy mice. H2S therapy may be beneficial for prevention and treatment of micro-vascular complications in patients with T2DM and HHcy.

Original languageAmerican English
Pages (from-to)215-225
Number of pages11
JournalRedox Biology
Volume16
DOIs
StatePublished - Jun 2018

Keywords

  • Acetylcholine/metabolism
  • Animals
  • Biological Factors/metabolism
  • Cardiovascular Diseases/genetics
  • Diabetes Mellitus, Type 2/genetics
  • Endothelium, Vascular/metabolism
  • Humans
  • Hydrogen Sulfide/metabolism
  • Hyperhomocysteinemia/genetics
  • Mesenteric Arteries/metabolism
  • Mice
  • Mice, Inbred NOD
  • Nitric Oxide/metabolism
  • Potassium Channel Blockers/metabolism
  • Vasodilation/genetics

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