title: FTY720 (fingolimod) increases vascular tone and blood pressure in spontaneously hypertensive rats via inhibition of sphingosine kinase.
abstract: OBJECTIVE
  FTY720 (Fingolimod) is a recently approved orally administered drug for the treatment of multiple sclerosis. Phase II and III clinical trials have demonstrated that this drug modestly increases BP. We previously showed that inhibition of sphingosine kinase increases vascular tone and BP in hypertensive, but not normotensive rats. Since FTY720 is reported to have inhibitory effects on sphingosine kinase, we investigated whether FTY720 increases vascular tone and BP only in hypertensive rats via this mechanism.
  
  
  METHODS
  The contractile and BP modulating effects of FTY720 were studied in vivo and ex vivo (wire myography) in age-matched normotensive Wistar Kyoto (WKY) rats and spontaneously hypertensive rats (SHRs).
  
  
  RESULTS
  Oral administration of FTY720 induced an increase in mean arterial pressure in SHR, whereas a decrease in BP was observed in WKY rats, as measured 24 h after administration. Similar to the sphingosine kinase inhibitor dimethylsphingosine (DMS), FTY720 induced large contractions in isolated carotid arteries from SHR, but not in those from WKY. In contrast, the phosphorylated form of FTY720 did not induce contractions in isolated carotid arteries from SHR. FTY720-induced contractions were inhibited by endothelium denudation, COX and thromboxane synthase inhibitors, and by thromboxane receptor antagonism, indicating that (like DMS-induced contractions) they were endothelium-dependent and mediated by thromboxane A₂.
  
  
  CONCLUSIONS
  These data demonstrate that FTY720 increases vascular tone and BP only in hypertensive rats, most likely as a result of its inhibitory effect on sphingosine kinase.
authors.affiliation: Department of Pharmacology & Pharmacotherapy, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Léon J A
authors.initials: LJ
authors.lastname: Spijkers
authors.forename: Astrid E
authors.initials: AE
authors.lastname: Alewijnse
authors.forename: Stephan L M
authors.initials: SL
authors.lastname: Peters
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002339:Carotid Arteries / Q000166:cytology / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D004791:Enzyme Inhibitors / Q000009:adverse effects / Q000737:chemistry / Q000494:pharmacology; D000068876:Fingolimod Hydrochloride; D006973:Hypertension / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D007166:Immunosuppressive Agents / Q000009:adverse effects / Q000737:chemistry / Q000494:pharmacology; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000378:metabolism; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D010766:Phosphorylation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011409:Propylene Glycols / Q000009:adverse effects / Q000737:chemistry / Q000494:pharmacology; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D013110:Sphingosine / Q000009:adverse effects / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology; D013928:Thromboxane A2 / Q000037:antagonists & inhibitors / Q000378:metabolism; D014655:Vascular Resistance / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000009:adverse effects / Q000737:chemistry / Q000494:pharmacology; D000099157:Sphingosine Kinase
chemical_list: D016861:Cyclooxygenase Inhibitors; D004791:Enzyme Inhibitors; D000068876:Fingolimod Hydrochloride; D007166:Immunosuppressive Agents; D007527:Isoenzymes; D017853:Phosphotransferases (Alcohol Group Acceptor); D011409:Propylene Glycols; D013110:Sphingosine; D013928:Thromboxane A2; D014662:Vasoconstrictor Agents; D000099157:Sphingosine Kinase