Age-related changes of anti-elastin antibodies in senescence-accelerated mice.

Background: Antibodies recognizing the elastin precursor tropoelastin (ATEAb) or degradation products alpha-elastin (AEAb) are found in the serum of healthy human subjects, as a part of a homeostatic mechanism which assembles new or clears altered elastin structures. Serum ATEAb (reflecting elastin synthesis) and AEAb (reflecting elastin destruction) appear to correlate with the production and breakdown of the elastic tissue, respectively.

Objective: The aim of this study was to investigate plasma levels of AEAb and ATEAb in senescence-accelerated prone (SAMP8) and senescence-accelerated resistant (SAMR1) mice, compared with imprinting control region (ICR) mice in order to evaluate their age-related changes.

Methods: The levels of AEAb and ATEAb were measured by home-made ELISA in plasma of SAMP8, SAMR1, and ICR mice, grouped according to their age (3 and 9 months) and sex. The specificity of AEAb and ATEAb activity in mouse plasma, and elastin-derived peptides (EDP) in sera of ICR mice at 3 and 9 months of age were tested by competitive ELISA.

Results: The specificity of AEAb and ATEAb in mouse plasma was confirmed by the competitive investigations. The levels of AEAb in the plasma of SAMR1 and SAMP8 were increased compared to the levels measured in ICR on the matched ages (p < 0.001). Age-related increase of the levels of AEAb and ATEAb was established in the 3 strains (p < 0.001). Significantly higher levels of AEAb were established in female 9-month-old mice compared to males in all strains. The ATEAb:AEAb ratio was significantly lower in the SAM compared to the ICR strain. Positive correlation was established between the levels of serum AEAb and EDP in mouse sera of ICR mice.

Conclusion: Variations with age in the plasma levels of AEAb and ATEAb were established in SAM compared with ICR, and in SAMP8 compared with SAMR1. Our findings suggest that increased anti-elastin IgG autoantibodies could be used as a marker of aging in SAM and possibly contribute to the processes of aging. The absence of a difference between SAMP8 and SAMR1 regarding the ATEAb:AEAb ratio raises the question if SAMR1 are an appropriate control of SAMP8 in terms of the senescence of the elastic tissues.