We had read with great interest the editorial by D.M. Bissel on the relationships between gender, fibrogenesis and remodeling of liver tissue.1 Several lines of evidence support the notion that sex may have some influence on the progression of fibrosis in chronic liver diseases. Female gender appears to be a protective factor and consistent data from observational and experimental studies suggest a fibrosuppressive effect of estrogens.2–4 However, whether density of extracellular matrix (ECM) in the liver of healthy subjects differs between men and women is unknown. Transient elastography is a new technique that allows noninvasive and reproducible measures of liver stiffness.5 This technique has been proved to be a reliable method for assessing hepatic fibrosis in different chronic liver diseases6–9 However and surprisingly, no systematic data on the stiffness of normal liver have been reported. Herein, we report our experience of liver stiffness measurement in healthy subjects with special regard with gender. We performed a transient elastography of the liver in 71 healthy persons, 33 men and 38 women, who had no history of liver disease, took no drug or alcohol and had normal blood liver tests. The median age was 34 yrs (range, 18-79 years). The median body mass index (BMI) was 22.5 kg.m−2 (range, 17.8-30.8 kg.m−2). Transient elastography was performed using the Fibroscan device (EchoSens, Paris, France) as previously described.9 The median value of liver stiffness was 4.8 kPa (range, 2.5-6.9 kPa). Liver stiffness was not correlated with age, body weight, height and BMI, but was significantly higher in men than in women (5.2 ± 0.7 vs. 4.5 ± 1.0, P < .01 for the Mann-Whitney test, Fig. 1), while BMI (23.4 ± 2.4 vs. 22.6 ± 3.2, NS) and age (35.8 ± 16.1 vs. 39.1 ± 16.4, NS) were similar in the two sexes. Liver stiffness was therefore associated with gender in an independent manner, an observation suggesting an intrinsic difference between men and women in density of the liver ECM. We consider that these data could be an additional argument in favor of a protective effect of female sex and ovarian hormones against the accumulation of ECM and fibrosis in the liver. This observation also suggests that gender potentially should be taken into account in the interpretation of liver stiffness measurement.
To the Editor,
C. Corpechot*, A. El Naggar*, R. Poupon*, * Service d'Hépatologie, Centre national de référence des maladies inflammatoires du foie et des voies biliaires, Hôpital Saint-Antoine, Paris, France.