Delayed wound healing may explain postoperative tissue and wound dehiscence in smokers, but the effects of smoking and smoking cessation on the cellular mechanisms remain unclear. Suction blisters were raised in 48 smokers and 30 never smokers. The fluid was retrieved and the epidermal roof was excised. Transepidermal water loss (TEWL) was measured after 2, 4, and 7 days. Then, the smokers were randomized to continuous smoking or abstinence with a transdermal nicotine patch or a placebo by concealed allocation. The sequence was repeated after 4, 8, and 12 weeks in all smokers and abstainers and in 6 never smokers. Matrix metalloproteinase (MMP)-8 and MMP-1 levels in suction blister fluid were assessed by an enzyme-linked immunosorbent assay. Random-effects models for repeated measurements were applied and p< or =0.05 was considered significant. One week after wounding the TEWL was 17.20 (14.47-19.92) g/cm(2) hour (mean, 95% CI) in smokers and 13.89 (9.46-18.33) in never smokers (p<0.01). In abstinent smokers TEWL was 18.95 (15.20-22.70)(p<0.01, when compared with smokers). In smokers, MMP-8 was 36.4 (24.3-48.5) ng/mL (mean, 95% CI) and 15.2 (1.4-30.2) ng/mL in never smokers (p<0.01). Abstinent smokers' MMP-8 level was 21.2 ng/mL (6.6-43.0) (p=0.02, when compared with smokers). MMP-1 was unaffected by smoking and abstention. Transdermal nicotine patch did not affect any parameter. We conclude that smoking attenuates epidermal healing and may enhance extracellular matrix degradation. Three months of abstinence from smoking does not restore epidermal healing, whereas 4 weeks of abstinence normalizes suction blister MMP-8 levels. These findings suggest sustained impaired wound healing in smokers and potential reversibility of extracellular matrix degradation.
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