Penn Cardiovascular Institute

Penn Cardiovascular Institute Research Directory

faculty photo

Bruce Sachais, M.D./Ph.D.

Associate Professor of Pathology and Laboratory Medicine at the Hospital of the University of Pennsylvania
Department: Pathology and Laboratory Medicine
Graduate Group Affiliations

Contact information
605A Stellar Chance
422 Curie Boulevard
University of Pennsylvania
Philadelphia, PA 19104
Office: 215 898-0568
Fax: 215 573-0252
B.A. (Chemistry)
Lehigh University , 1988.
Washington University, 1996.
Ph.D. (Neuroscience)
Washington University, 1996.
Certif. (Patient Oriented Research)
University of Pennsylvania, 2005.
Permanent link
> Perelman School of Medicine   > Faculty   > Details

Description of CVI Expertise

CVI Program Unit(s):
Lipid / Atherosclerosis / CAD / ACS / Prevention
Thrombosis / Hemostasis

CVI Research Description:
The Sachais Lab is primarily interested in the biology and structure of platelet factor 4 (PF4). PF4 is a cationic protein found in the a-granules of platelets and is released upon platelet activation. It binds avidly to glycosaminoglycans on the surface of endothelial cells and is known to inhibit anti-thrombin III, resulting in increased clotting.

We are interested in the role of PF4 in several diseases, specifically atherosclerosis and heparin induced thrombocytopenia (HIT). We have found that PF4 is localized in atherosclerotic lesions and that the presence of PF4 correlated with pathological and clinical disease progression. Further, we have found that in vitro PF4 inhibits endocytosis of the LDL receptor, resulting in decreased LDL degradation and retention of LDL on the cell surface. Current studies are underway to further understand the cellular and molecular mechanisms responsible for this phenomenon and to examine the effects of PF4 on other lipoproteins and lipoprotein receptors. In vivo experiments are currently underway to further our understanding of these phenomena.

Another project in the lab is examining the molecular mechanisms of HIT. This rare but serious complication of heparin therapy is known to involve the recognition of PF4:heparin complexes by pathogenic auto-antibodies. It is also known that altering the ratio of heparin to PF4 alters the recognition of the complexes. Our working hypothesis is that the structure of the complexes formed at different heparin:PF4 ratios differs and that the structural changes are important for the expression of disease. We are investigating these structural changes and how these changes effect pathogenesis of HIT. Both in vitro and in vivo systems are being employed.

Selected Publications

Cho, M.J., Lo, A.S.Y., Mao, X., Nagler, A.R., Ellebrecht, C.T., Mukherjee, E.M., Hammers, C.M., Choi, E.J., Sharma, P.M., Uduman, M., Li, H., Rux, A.H., Farber, S.A., Rubin, C.B., Kleinstein, S.H., Sachais, B.S., Posner, M.R., Cavacini, L.A., Payne, A.S.: Shared VH1-46 gene usage by pemphigus vulgaris autoantibodies indicates common humoral immune responses among patients. Nature Communications IN PRESS, 2014.

Farooqi, M.S., Lai, Y., Lancaster, E., Schmitt, S.E., Sachais, B.S.: Therapeutic Plasma Exchange and Immunosuppressive Therapy in a Patient with Anti-GAD Antibody-Related Epilepsy: Quantification of the Antibody Response. Journal of Clinical Apheresis In Press, 2014.

Cuker A.,Rux A.H., Hinds J.L., Dela Cruz M., Yarovoi S.V., Brown I.A., Yang W., Konkle B.A., Arepally G.M., Watson S.P., Cines D.B., Sachais, B.S.: Novel diagnostic assays for heparin-induced thrombocytopenia. BLOOD 121: 3727-3732, May (Feb Ahead of print) 2013.

Callan, M.B., Patel, R.T., Rux, A.H., Bandyopadhyay, S., Sireci, A.N., ODonnel, P.A., Ruane, T., Sikora, T., Marryott, K., Sachais, B.S., and Hod, E.A.: Transfusion of 28-day-old leucoreduced or non-leukoreduced stored red blood cells introduces an inflammatory response in healthy dogs. Vox Sanguinis 105(4): 319-27, 2013.

Litvinov, R.I., Yarovoi, S.V., Rauova, L., Barsegov, V., Sachais, B.S., Rux, A.H., Hinds, J.L., Arepally, G.M., Cines, D.B., Weisel, J.W.: Distinct Specificity and Single-molecule Kinetics Characterize the Interaction of Pathogenic and Non-pathogenic Antibodies against Platelet Factor 4-Heparin Complexes with Platelet Factor 4. Journal of Biological Chemistry 288(46): 33060-70, 2013.

Tanhehco, Y.C., Cuker, A., Rudnick, M., and Sachais, B.S.: Investigation of a potential protective mechanism against heparin-induced thrombocytopenia in patients on chronic intermittent hemodialysis. Thrombosis Research 131: 244-248, 2013 Notes:

Sachais, B.S., Litvinov, R.I., Yarovoi, S.V., Rauova, L., Hinds, J.L., Rux, A.H., Arepally, G.M., Poncz, M., Cuker, A., Weisel, J.W., and Cines, D.B.: Dynamic antibody binding properties in the pathogenesis of HIT. Blood 120: 1137-1142, August 2012 Notes: PMID: 22577175 (Editorial Accompanying).

Sachais, B.S., Rux. A.H, Cines, D.B., Yarovoi, S.V., Garner, L.I., Watson S.P., Hinds, J.L., Rux,J.J.: Rational design and characterization of platelet factor 4 antagonists for the study of heparin-induced thrombocytopenia. Blood 119(25): 5955-5962, June 2012 Notes: Plenary Paper. Inside Blood Accompanying.

Marshall, C.S., Andrzejewski, C., Carey, P.M., Crookston, K.P., Li, K., Lopez-Plaza, I., Sachais, B.S., Schwartz, J., Winters, J.L., Wong E.C.C, and Wu, Y.: Milestones for apheresis education. Journal of Clinical Apheresis Page: Epub Ahead of Print, June 2012.

Yvette C. Tanhehco, Ann H. Rux, and Bruce S. Sachais: Low Density Lipoprotein Apheresis Reduces PF4 on the Surface of Platelets: a Possible Protective Mechanism Against HITT. Transfusion 51: 1022-1029, October 2010 Notes: PMID: 20977482

back to top
Last updated: 09/12/2014
The Trustees of the University of Pennsylvania