title: Low levels of low-density lipoprotein-C associated with proprotein convertase subtilisin kexin 9 inhibition do not increase the risk of hemorrhagic transformation.
abstract: OBJECTIVE
  Low levels of low-density lipoprotein-cholesterol (LDL-C) are suspected to be associated with a risk of hemorrhagic transformation after ischemic stroke. We assessed the risk of hemorrhagic transformation after cerebral ischemia/reperfusion in mice with low levels of LDL-C resulting from proprotein convertase subtilisin kexin 9 (PCSK9) deficiency.
  
  
  METHODS
  PCSK9-/- and PCSK9+/+ mice were fed with a high-fat/high-cholesterol (21%/0.15%) diet for 1 month. Plasma lipids were measured using colorimetric assays. PCSK9-/- and PCSK9+/+ mice (n=15 per group) were subjected to a 4-hour intraluminal occlusion of the middle cerebral artery followed by 20 hours of reperfusion. Spontaneous hemorrhagic transformation was assessed by quantification of hemoglobin in ischemic tissue. In vitro, a cell model of blood-brain barrier was used to test endothelial barrier integrity in response to decreasing concentrations of LDL-C from 1 to 0.25g/L in ischemia/reperfusion conditions.
  
  
  RESULTS
  PCSK9-/- mice had lower LDL-C, high-density lipoprotein-cholesterol, and total cholesterol levels than PCSK9+/+ mice before and after 1 month on the high-fat/high-cholesterol diet. Hemoglobin concentration in ischemic cerebral tissue was not different between PCSK9-/- and PCSK9+/+ mice (31.5 [18.9-60.1] and 32.8 [14.7-69.9] ng/mg protein, respectively; P=0.81). Infarct volume was also similar in both groups (P=0.66). Incubation of human cerebral endothelial cells with decreasing concentrations of LDL-C under ischemia/reperfusion conditions did not alter blood-brain barrier permeability.
  
  
  CONCLUSIONS
  Low levels of LDL-C did not increase the risk of hemorrhagic transformation after cerebral ischemia/reperfusion in mice. Our observations suggest that PCSK9 inhibition, leading to LDL-C lowering, should not increase hemorrhagic complications after acute ischemic stroke.
authors.affiliation: From the Inserm UMR1148, Paris7 University, Xavier Bichat Hospital, Paris, France (A.T.-D., A.L., L.L., C.J., O.M., P.A.); Paris 7 University, Université Paris Diderot, Paris, France (A.T.-D., P.A.); CHU Bichat Stroke Center, Paris, France (P.A.); CHU de La Réunion, Saint-Pierre, France (O.M.); Paris 13 University, Villetaneuse, France (A.L.); UMR PhAN Laboratory, Nantes, France (G.L.); and University of Nantes Medical School, Nantes, France (G.L.).
authors.forename: Alexy
authors.initials: A
authors.lastname: Tran-Dinh
authors.affiliation: From the Inserm UMR1148, Paris7 University, Xavier Bichat Hospital, Paris, France (A.T.-D., A.L., L.L., C.J., O.M., P.A.); Paris 7 University, Université Paris Diderot, Paris, France (A.T.-D., P.A.); CHU Bichat Stroke Center, Paris, France (P.A.); CHU de La Réunion, Saint-Pierre, France (O.M.); Paris 13 University, Villetaneuse, France (A.L.); UMR PhAN Laboratory, Nantes, France (G.L.); and University of Nantes Medical School, Nantes, France (G.L.).
authors.forename: Angélique
authors.initials: A
authors.lastname: Levoye
authors.affiliation: From the Inserm UMR1148, Paris7 University, Xavier Bichat Hospital, Paris, France (A.T.-D., A.L., L.L., C.J., O.M., P.A.); Paris 7 University, Université Paris Diderot, Paris, France (A.T.-D., P.A.); CHU Bichat Stroke Center, Paris, France (P.A.); CHU de La Réunion, Saint-Pierre, France (O.M.); Paris 13 University, Villetaneuse, France (A.L.); UMR PhAN Laboratory, Nantes, France (G.L.); and University of Nantes Medical School, Nantes, France (G.L.).
authors.forename: Gilles
authors.initials: G
authors.lastname: Lambert
authors.affiliation: From the Inserm UMR1148, Paris7 University, Xavier Bichat Hospital, Paris, France (A.T.-D., A.L., L.L., C.J., O.M., P.A.); Paris 7 University, Université Paris Diderot, Paris, France (A.T.-D., P.A.); CHU Bichat Stroke Center, Paris, France (P.A.); CHU de La Réunion, Saint-Pierre, France (O.M.); Paris 13 University, Villetaneuse, France (A.L.); UMR PhAN Laboratory, Nantes, France (G.L.); and University of Nantes Medical School, Nantes, France (G.L.).
authors.forename: Liliane
authors.initials: L
authors.lastname: Louedec
authors.affiliation: From the Inserm UMR1148, Paris7 University, Xavier Bichat Hospital, Paris, France (A.T.-D., A.L., L.L., C.J., O.M., P.A.); Paris 7 University, Université Paris Diderot, Paris, France (A.T.-D., P.A.); CHU Bichat Stroke Center, Paris, France (P.A.); CHU de La Réunion, Saint-Pierre, France (O.M.); Paris 13 University, Villetaneuse, France (A.L.); UMR PhAN Laboratory, Nantes, France (G.L.); and University of Nantes Medical School, Nantes, France (G.L.).
authors.forename: Clément
authors.initials: C
authors.lastname: Journé
authors.affiliation: From the Inserm UMR1148, Paris7 University, Xavier Bichat Hospital, Paris, France (A.T.-D., A.L., L.L., C.J., O.M., P.A.); Paris 7 University, Université Paris Diderot, Paris, France (A.T.-D., P.A.); CHU Bichat Stroke Center, Paris, France (P.A.); CHU de La Réunion, Saint-Pierre, France (O.M.); Paris 13 University, Villetaneuse, France (A.L.); UMR PhAN Laboratory, Nantes, France (G.L.); and University of Nantes Medical School, Nantes, France (G.L.).
authors.forename: Olivier
authors.initials: O
authors.lastname: Meilhac
authors.affiliation: From the Inserm UMR1148, Paris7 University, Xavier Bichat Hospital, Paris, France (A.T.-D., A.L., L.L., C.J., O.M., P.A.); Paris 7 University, Université Paris Diderot, Paris, France (A.T.-D., P.A.); CHU Bichat Stroke Center, Paris, France (P.A.); CHU de La Réunion, Saint-Pierre, France (O.M.); Paris 13 University, Villetaneuse, France (A.L.); UMR PhAN Laboratory, Nantes, France (G.L.); and University of Nantes Medical School, Nantes, France (G.L.).
authors.forename: Pierre
authors.initials: P
authors.lastname: Amarenco
mesh_terms: D000818:Animals; D001812:Blood-Brain Barrier / Q000378:metabolism / Q000473:pathology; D002460:Cell Line; D002543:Cerebral Hemorrhage / Q000453:epidemiology* / Q000378:metabolism; D008078:Cholesterol, LDL / Q000097:blood*; D042783:Endothelial Cells / Q000378:metabolism; D006801:Humans; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D000071449:Proprotein Convertase 9; D043484:Proprotein Convertases / Q000037:antagonists & inhibitors* / Q000172:deficiency; D015427:Reperfusion Injury / Q000150:complications / Q000378:metabolism; D012307:Risk Factors; D012697:Serine Endopeptidases / Q000172:deficiency; D020521:Stroke / Q000150:complications* / Q000378:metabolism
chemical_list: D008078:Cholesterol, LDL; C472126:Pcsk9 protein, mouse; D000071449:Proprotein Convertase 9; D043484:Proprotein Convertases; D012697:Serine Endopeptidases
keywords: PCSK9 protein; hemorrhage; low-density lipoprotein cholesterol; mice; stroke