Human vascular smooth muscle cells of diabetic origin exhibit increased proliferation, adhesion, and migration.
OBJECTIVE
Patients with diabetes mellitus (DM) experience progressive macrovascular atherosclerosis and intimal hyperplastic restenosis with increased frequency as compared with nondiabetic patients. These observations suggest that vascular smooth muscle cells (VSMCs) behave in a phenotypically different and more aggressive manner in diabetic patients. In this study, we compared the in vitro rates of proliferation, adhesion, and migration of human VSMCs obtained from diabetic and nondiabetic patients.


METHODS
Human VSMC cultures were isolated from 23 diabetic patients (9 artery, 14 vein) and 15 nondiabetic patients (9 artery, 6 vein) with extensive lower extremity atherosclerosis. All patients were between 61 and 78 years of age (average: 68.4 years [diabetic]; 67.3 years [nondiabetic]). All diabetic patients had type 2 DM. Vascular specimens were obtained at the time of amputation from infragenicular arteries and during arterial revascularization from saphenous veins. Cells from passages 2 and 3 were assayed for their proliferative capacity with total DNA fluorescence photometry and for adhesion and migration with a modified Boyden chamber.


RESULTS
The average duration of diabetes was 11.6 +/- 4.1 years. The average number of diabetic complications (retinopathy, neuropathy, nephropathy, coronary artery disease) was 2.8 +/- 0.7 per patient. Diabetic VSMCs exhibited abnormal morphology in cell culture with loss of the normal hill and valley configuration. Proliferation was significantly increased in VSMCs of diabetic origin (156 +/- 57 absorption units) as compared with those of nondiabetic origin (116 +/- 42 absorption units) (P <.001). Diabetic VSMCs demonstrated significantly greater adhesion (63.6 +/- 24 per high-power field vs 37.9 +/- 13 per high-power field; P =.002) and migration (397 +/- 151 per low-power field vs 121 +/- 99 per low-power field; P =.001) rates.


CONCLUSIONS
Diabetic VSMCs exhibit significantly increased rates of proliferation, adhesion, and migration as well as abnormal cell culture morphology suggestive of abnormal contact inhibition. These observations of human VSMCs in culture are consistent with the increased rate of infragenicular atherosclerosis and the increased rates of restenosis observed clinically in diabetic patients. The atherosclerosis- and intimal hyperplasia-promoting behavior exhibited appears to be intrinsic to the DM-VSMC phenotype and must be considered when designing methods to limit atherosclerosis and intimal hyperplasia in diabetic patients.
Division of Vascular Surgery, Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA. peter.faries@mssm.edu
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Faries
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Rohan
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Takahara
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Wyers
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Contreras
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Quist
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King
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Logerfo
D000368:Aged; D001161:Arteriosclerosis / Q000473:pathology; D002448:Cell Adhesion / Q000502:physiology*; D002455:Cell Division / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology*; D002478:Cells, Cultured; D003925:Diabetic Angiopathies / Q000473:pathology*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D009131:Muscle, Smooth, Vascular / Q000473:pathology*