Stem villous arteries from the placentas of heavy smokers: Functional and mechanical properties

OBJECTIVE: The aim of the study was to compare the mechanical and functional properties of isolated small stem villous arteries from the placentas of women who smoked heavily (greater than or equal to 15 cigarettes/d) during pregnancy with those from the placentas of nonsmokers. STUDY DESIGN: Isolated stem villous arteries were mounted in small-vessel myographs. Circumference-tension relationships were established with 124 mmol/L potassium chloride. Concentration-response curves were obtained for endothelin 1, prostaglandin F-2 alpha, vasoactive intestinal peptide, corticotropin-releasing hormone, sodium nitroprusside, and cadmium chloride. The effect of nitric oxide was examined with N-omega-nitro-L-arginine. RESULTS: Stem villous arteries from the heavy smoking group developed a significantly lower tension than did those from nonsmokers at 6 of 9 steps of the circumference-tension experiment (P < .05). Endothelin 1 evoked a significantly greater maximum vasoconstrictive response in stem villous arteries from heavy smokers than in those from nonsmokers (P < .05). CONCLUSION: Stem villous arteries of heavy smokers have altered mechanical properties and a greater vasoconstrictive response to endothelin 1 than do those from nonsmokers. These changes may compromise fetal placental blood flow and thereby contribute to the lower birth weights seen among infants born to heavy smokers.