title: Platelet gene therapy improves hemostatic function for integrin alphaIIbbeta3-deficient dogs.
abstract: Activated blood platelets mediate the primary response to vascular injury. Although molecular abnormalities of platelet proteins occur infrequently, taken collectively, an inherited platelet defect accounts for a bleeding diathesis in ≈1:20,000 individuals. One rare example of a platelet disorder, Glanzmann thrombasthenia (GT), is characterized by life-long morbidity and mortality due to molecular abnormalities in a major platelet adhesion receptor, integrin αIIbβ3. Transfusion therapy is frequently inadequate because patients often generate antibodies to αIIbβ3, leading to immune-mediated destruction of healthy platelets. In the most severe cases allogeneic bone marrow transplantation has been used, yet because of the risk of the procedure it has been limited to few patients. Thus, hematopoietic stem cell gene transfer was explored as a strategy to improve platelet function within a canine model for GT. Bleeding complications necessitated the use of a mild pretransplant conditioning regimen; therefore, in vivo drug selection was used to improve engraftment of autologously transplanted cells. Approximately 5,000 αIIbβ3 receptors formed on 10% of platelets. These modest levels allowed platelets to adhere to αIIbβ3's major ligand (fibrinogen), form aggregates, and mediate retraction of a fibrin clot. Remarkably, improved hemostatic function was evident, with ≤135-fold reduced blood loss, and improved buccal bleeding times decreased to 4 min for up to 5 y after transplant. One of four transplanted dogs developed a significant antibody response to αIIbβ3 that was attenuated effectively with transient immune suppression. These results indicate that gene therapy could become a practical approach for treating inherited platelet defects.
authors: Department of Pediatrics and Biomedical Resource Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
authors: Juan
authors: J
authors: Fang
authors: Eric S
authors: ES
authors: Jensen
authors: Mary K
authors: MK
authors: Boudreaux
authors: Lily M
authors: LM
authors: Du
authors: Troy B
authors: TB
authors: Hawkins
authors: Sevasti B
authors: SB
authors: Koukouritaki
authors: Kenneth
authors: K
authors: Cornetta
authors: David A
authors: DA
authors: Wilcox
references: Blood. 1990 Apr 1;75(7):1383-95
references: 2180491
references: Proc Natl Acad Sci U S A. 2004 Sep 7;101(36):13114-20
references: 15277669
references: Proc Natl Acad Sci U S A. 1999 Aug 17;96(17):9654-9
references: 10449749
references: J Virol. 2003 Aug;77(16):8957-61
references: 12885912
references: Blood. 2003 Jul 15;102(2):506-13
references: 12663444
references: Blood. 1998 Mar 15;91(6):1977-86
references: 9490680
references: Thromb Haemost. 1995 Jul;74(1):234-9
references: 8578464
references: Blood. 1999 Dec 1;94(11):3951-3
references: 10572113
references: Biol Blood Marrow Transplant. 2005 Oct;11(10):755-63
references: 16182176
references: Pediatr Blood Cancer. 2005 Dec;45(7):971-5
references: 15768382
references: Transl Res. 2007 Aug;150(2):81-92
references: 17656327
references: Exp Hematol. 1991 Jan;19(1):47-52
references: 1989894
references: Blood. 2005 Oct 15;106(8):2671-9
references: 15972454
references: Am J Vet Res. 2001 Sep;62(9):1486-92
references: 11560282
references: Thromb Haemost. 2008 Feb;99(2):253-63
references: 18278172
references: Blood. 2004 May 15;103(10):3710-6
references: 14739227
references: Vet Pathol. 2000 Nov;37(6):581-8
references: 11105947
references: Proc Natl Acad Sci U S A. 1991 Apr 15;88(8):3160-4
references: 2014236
references: J Clin Invest. 1963 Jun;42:747-55
references: 13936148
references: Nat Med. 2008 Jan;14(1):93-7
references: 18157138
references: Hum Gene Ther. 2010 Apr;21(4):397-403
references: 19947827
references: Blood. 2008 Oct 15;112(8):3011-25
references: 18840725
references: Hum Gene Ther. 2003 Apr 10;14(6):497-507
references: 12718761
references: Blood. 2008 Oct 1;112(7):2780-6
references: 18641368
references: Blood. 2009 Jun 25;113(26):6511-21
references: 19395674
references: Am J Vet Res. 1987 Sep;48(9):1337-42
references: 3499100
references: Science. 2010 Apr 30;328(5978):562-4
references: 20430990
references: Exp Hematol. 2003 Dec;31(12):1357-62
references: 14662345
references: J Vet Intern Med. 1996 Sep-Oct;10(5):290-5
references: 8884713
references: Blood. 1996 Sep 15;88(6):2062-70
references: 8822925
references: J Clin Invest. 1995 Apr;95(4):1553-60
references: 7706461
references: J Clin Invest. 2010 Jul;120(7):2345-54
references: 20551514
references: Blood. 2000 Jun 15;95(12):3645-51
references: 10845892
references: Can Vet J. 1985 Aug;26(8):245-50
references: 17422562
references: J Clin Invest. 2003 Nov;112(10):1581-8
references: 14617759