Smoking affects collagen synthesis and extracellular matrix turnover in human skin

BACKGROUND: Smoking is associated with premature facial wrinkling and aberrant wound healing, but the underlying mechanisms of skin injury are poorly understood. OBJECTIVES: To compare the in vivo collagen synthesis and degradation in the skin of smokers and non-smokers. METHODS: The study population consisted of 47 current smokers and 51 individuals who had never smoked from northern Finland. Suction blisters were induced in the sun-protected upper inner arm of the study subjects, after which suction blister fluid (SBF) was collected for analyses of the levels of aminoterminal procollagen propeptides of type I and III collagens (PINP and PIIINP, respectively), matrix metalloproteinase (MMP)-8 and tissue inhibitor of MMP (TIMP)-1. PINP, PIIINP and TIMP-1 were also determined from serum samples. The levels of active and pro MMP-1 were assessed from deep-frozen skin biopsies by Western blotting. RESULTS: The synthesis rates of type I and III collagens were lower by 18% and 22%, respectively, in the SBF of the smokers compared with the non-smokers. The levels of MMP-8 were higher by 100% in the SBF of the smokers. The levels of MMP-1 in the skin biopsies did not differ significantly between the groups. The levels of TIMP-1 in SBF were 14% lower in the smokers than in the non-smokers, whereas the serum concentrations of TIMP-1 did not differ between the groups. CONCLUSIONS: Smoking decreases the synthesis rates of type I and III collagens in skin in vivo and alters the balance of extracellular matrix turnover in skin.