ORIGINAL ARTICLES   

International Angiology 2000 March;19(1):39-46

Copyright © 2001 EDIZIONI MINERVA MEDICA

lingua: Inglese

Direct and indirect effects of pulsatile shear stress on the smooth muscle cell

Shigematsu K., Yasuhara H., Shigematsu H., Muto T.

From the Division of Vascular Surgery, Department of Surgery, The University of Tokyo, Tokyo, Japan

Background. Anastomotic inti­mal hyper­pla­sia is still an ­unsolved prob­lem after small cal­i­ber pros­thet­ic ­bypass graft­ing. Oscillatory tur­bu­lent flow ­occurs at the end to side anas­tom­o­sis, and pro­duc­es var­i­ous ­effects on ­smooth mus­cle cells (SMCs) and endo­the­lial cells (ECs), which com­pose inti­mal hyper­pla­sia. We exam­ined the influ­enc­es of pul­sa­tile oscil­lat­ing shear ­stress on SMCs mit­o­gen­ic activ­ity ­induced by ­sheared ECs.
Methods. 1) SMCs were cul­tured under three dif­fer­ent pul­sa­tile shear con­di­tions (mean: 0, 6, and 60 dyne/cm2).
2) ECs were cul­tured under both stat­ic and ­sheared con­di­tion (mean: 60 dyne/cm2). Using the con­di­tioned media from each well, SMCs were cul­tured under stat­ic and ­sheared con­di­tions (60 dyne/cm2). Four ­groups of SMCs were ­devised by com­bin­ing the two types of media and the two cul­ture con­di­tions. SMC col­o­ny spread­ing dis­tanc­es were meas­ured as an index of com­bined migra­tion and pro­life­ra­tion activ­ity. An MTT assay and a cell count­ing assay were used to deter­mine the pro­life­ra­tion activ­ities of SMCs.
Results. 1) SMC spread­ing activ­ity was sup­pressed by shear ­stress. SMC pro­life­ra­tive activ­ity was stim­u­lat­ed by pul­sa­tile tur­bu­lent shear ­stress. 2) SMC spread­ing activ­ity was stim­u­lat­ed by mito­gens ­derived from ECs under shear ­stress. However, this aug­ment­ed SMC spread­ing activ­ity was atten­u­at­ed under ­sheared con­di­tions. The mito­gens ­derived from ECs under pul­sa­tile shear ­stress had no ­effects on SMC pro­life­ra­tion activ­ity.
Conclusions. Pulsatile oscil­lat­ing shear ­stress atten­u­ates SMC migra­tion activ­ity ­induced by EC-derived mito­gens and stim­u­lates SMC pro­life­ra­tive activ­ity.