#13. PROGRAMMED CELL DEATH (APOPTOSIS) AND ITS
ROLE IN THE PATHOGENESIS OF LOWER EXTREMITY VARICOSE VEINS.
Enrico Ascher, MD, Theresa Jacob, PhD, Anil Hingorani, MD,
Fernanda Mazzariol, MD, Prasad Gade, MD, Maria E. Fodera, MD, M.
Mahmood, MD, and Sreedhar Kallakuri, MD
Maimonides Medical Center, Brooklyn, NY
Purpose: The etiology of varicose veins remains elusive. We
hypothesized that abnormal events in the cell cycle within the vein
wall may contribute to the development of varicose veins. Since cell
cycle checkpoint controls are linked to the signaling and execution
of apoptotic cascades, it is possible that apoptosis may be a
contributing factor in the pathophysiology of varicosities. The
present study was designed to investigate whether programmed cell
death varies in varicose veins as compared to normal veins.
Materials and Methods: Twenty-seven normal greater saphenous
vein specimens were obtained from 27 patients (18 males, 9 females)
undergoing infrainguinal arterial bypass surgery and found to be free
of acute or chronic inflammation by hematoxylin and eosin staining.
Twenty varicose vein specimens were retrieved from 20 patients (7
males, 13 females) undergoing lower extremity varicose vein excision.
All vein specimens were fixed in paraformaldehyde and
paraffin-embedded. Paraffin blocks contained 5 different segments of
each specimen. Tissue section of 5 mm thickness were processed by
standard immunohistochemistry techniques. Detection of apoptosis in
the venous tissue was attempted by terminal deoxynucleotidyl
transferase (Tdt)/digoxigenin-dUTP end-labeling of free 3' OH DNA
termini of fragmented DNA present in the apoptotic cells (TUNEL). In
each specimen, the number of apoptotic cells per 1000 were counted
manually at 1000x magnification. Fisher's Exact Test was used to
compare the results obtained in the different groups.
Results: Apoptotic cells were identified in 32 of the 47
specimens (68%). The apoptotic indices for the adventitia, media and
intima in the normal vein group were 4.38, 0.20, and 0.44
respectively, and for the varicose veins they were 1.58, 0.19, and
0.44 respectively. Thirteen of 27 (48%) normal vein specimens
displayed more than 3 apoptotic cells per hundred cells in the
adventitia, while only 3 of 20 (15%) in the varicose vein group
showed such magnitude of apoptosis (p<0.03). Moreover, this
increased apoptotic activity (>3 cells/100) was not observed in
the normal vein group media and intima (0/27) (p<0.001), nor on
those layers of the varicose vein group.
Conclusions: These data show that the process of programmed
cell death is inhibited in varicose veins. It is possible that an
increase in the survival of the adventitial cells may lead to an
insurgence of mutations that may cause weakening or dilatation of the
venous wall. We also found significantly less apoptotic activity in
both the media and intima of normal veins when compared to the
adventitia. Further work is necessary to elucidate the importance of
the latter findings in the pathogenesis of varicose veins.
