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 nonsmokers, 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.