Cigarette smoking is associated with various cutaneous disorders with defective permeability. Yet, whether cigarette smoking influences epidermal permeability barrier function is largely unknown. Here, we measured skin biophysical properties, including permeability barrier homeostasis, stratum corneum (SC) integrity, SC hydration, skin surface pH, and skin melanin/erythema index, in cigarette smokers. A total of 99 male volunteers were enrolled in this study. Smokers were categorized as light-to-moderate (<20 cigarettes/day) or heavy smokers (≥20 cigarettes/day). An MPA5 was used to measure SC hydration and skin melanin/erythema index on the dorsal hand, forehead, and cheek. Basal transepidermal water loss (TEWL) and barrier recovery rates were assessed on the forearm. A Skin-pH-Meter pH900 was used to measure skin surface pH. Our results showed that heavy cigarette smokers exhibited delayed barrier recovery after acute abrogation (
Cigarette smoke negatively impacts human health in multiple organ systems. Previous studies have shown that cigarette smoking inhibits not only sympathetic nerve activity [
Cigarette smoke also impacts cutaneous function. Cigarette smoke delays cutaneous wound healing [
The development of psoriasis and atopic dermatitis is associated with defective epidermal permeability barrier function [
A total of 99 male volunteers, including 63 smokers and 36 nonsmokers, aged 41–65 years (mean
Clinical characteristics of subjects.
Group | |
Age | Years of smoking | Number of cigarettes/day |
---|---|---|---|---|
Nonsmokers | 36 | 53.00 ± 1.20 | N/A | N/A |
All smokers | 63 | 54.21 ± 0.81 | 28.79 ± 1.16 | 18.03 ± 1.15 |
≥20 cigarettes/day | 36 | 54.72 ± 1.04 | 30.28 ± 1.18 | 23.61 ± 1.27 |
<20 cigarettes/day | 27 | 53.52 ± 1.26 | 26.81 ± 2.17 | 10.59 ± 0.88 |
All measurements were randomly performed by two fully trained dermatologists. TEWL and SC electrical capacitance were measured on the right dorsal hand, right cheek, and forehead with respective probes (TM300 and Corneometer CM825) attached to a Courage-Khazaka MPA5 system [
All subjects have been given their informed consent.
GraphPad Prism 4 software was used for all statistical analyses. An unpaired
We first assessed epidermal permeability barrier homeostasis on the forearm of smokers versus nonsmokers. While there were no differences in basal TEWL between smokers and nonsmokers (Figure
Changes in epidermal permeability barrier function in cigarette smokers. Basal TEWL and barrier repair kinetics on the forearm were determined as described in Subjects and Methods. A one-way ANOVA Kruskal-Wallis test was used to determine significant differences as shown in (a) and (b). (c) shows correlation between barrier recovery rates and the number of cigarettes smoked. The number of subjects in each group is described in Table
Comparison of stratum corneum integrity between smokers and nonsmokers. Stratum corneum integrity on the forearm was assessed by measuring TEWL after each D-Squame application. A total of 6 D-Squames were applied. An unpaired two-tailed Student’s
Since the permeability barrier is closely associated with changes in skin surface pH and stratum corneum hydration [
Comparison of epidermal biophysical properties between smokers and nonsmokers. (a) and (b) depict skin surface pH and stratum corneum hydration, respectively, while (c) and (d) display the melanin and erythema index, respectively. The number of subjects in each group is detailed in Table
Cigarette smoke is a major public health issue, because it is associated with the pathogenesis of a variety of clinical disorders [
The mechanisms by which cigarette smokers display such diverse differences in permeability barrier homeostasis are not clear. But several studies have shown that nicotine, a major ingredient in cigarettes, regulates keratinocyte functions. Addition of nicotine to keratinocyte cultures increases filaggrin and involucrin expression [
The present study also demonstrates that stratum corneum hydration is high on sebaceous gland-enriched sites (the forehead and cheeks) of smokers. This change could reflect increased sebum production, induced by nicotine. A previous study showed that nicotine stimulates sebocyte proliferation and lipid production [
In summary, the present study shows that changes in epidermal permeability barrier homeostasis correlate with the number of cigarettes smoked daily, suggesting a pathogenic role of cigarette smoking in the development of certain cigarette-associated disorders. Therefore, the improvement of epidermal permeability barrier is important for cigarette smokers, particularly heavy smokers.
The authors declare that they have no competing interests.
Shujun Xin and Li Ye contributed equally to this work.
This work was supported in part by the resources and uses of facilities at the Veterans Affairs Medical Center, San Francisco, California, USA.