Elucidating the Mechanism by Which Protamine Negates Heparin's Antiproliferative Effect on Smooth Muscle Cells

Carmen R. Berg
Work conducted in the laboratory of Elazer R. Edelman, MD, PhD*+
*Harvard-MIT Division of Health, Sciences, and Technology, Massachusetts Institute of Technology, Cambridge MA 02139
+Cardiovascular Division, Department of Medicine, Brigham and Women¹s Hospital, Harvard Medical School, Boston Massachusetts, 02115 USA

Fig. 7: The effect of non-preincubated protamine and heparin on bovine aortic SMCs in 5% calf serum/DMEM. Various doses of 1 mg/ml protamine sulfate and heparin chloride solutions were added with 5% calf serum/DMEM to growth arrested bovine aortic SMCs (passage 7). Values are means ± standard error. The results from Figure 7 and Figure 8 differ even though the amount of protamine and heparin are identical. The only difference in the conditions are that the results of Figure 8 are from cells to which preincubated protamine and heparin were added, while this figure shows results of SMC growth when these compounds were not preincubated. Inset: % stimulation or % inhibition of SMCs from non-preincubated protamine and heparin in 5% calf serum/DMEM. A positive number indicates stimulation, while a negative number indicates inhibition. Fig. 8: The effect of preincubated protamine and heparin on bovine aortic SMCs in 5% calf serum/DMEM. Various doses of 1 mg/ml protamine sulfate and heparin chloride solutions were preincubated with 5% calf serum/DMEM for 24 hours. These solutions were then added to growth arrested bovine aortic SMCs (passage 7). Values are means ± standard error. The results from Figure 7 and Figure 8 differ even though the amount of protamine and heparin are identical. The only difference in the conditions are that the results of this figure are from cells to which preincubated protamine and heparin were added, while this Figure 7 shows results of SMC growth when these compounds were not preincubated. Inset: % stimulation or % inhibition of SMCs from preincubated protamine and heparin in 5% calf serum/DMEM. A positive number indicates stimulation, while a negative number indicates inhibition.