Plasma fibronectin in French centenarians

Plasma fibronectin was shown to increase with age, the difference between i ndividuals (the SD of the mean) also increases with age. Fibronectin is hig hly sensitive to proteolytic degradation and several of the degradation pro ducts were shown to have noxious effects as proper proteolytic activity, ac tivation of IL-I and collagenase expression and also activation of fibronec tin biosynthesis. It was therefore interesting to compare the plasma fibron ectin values of centenarians in relatively good health with an elderly popu lation in a geriatric hospital, somewhat younger (70-96 years) but with a v ariety of pathologies. A third population of men and women between 59 and 7 0 in good health (the EVA-epidemiological study) was also used for comparis on. Plasma fibronectin was determined by a specific and highly sensitive El isa assay. Fibronectin fragments were characterised by immunoblot. It could be shown that plasma fibronectin in centenarians had a lower distribution with lower average values than the geriatric population. Fibronectin fragme nts could be demonstrated in the plasma of a selection of geriatric patents but not in the plasma of centenarians. These results suggest a more modera te increase of plasma fibronectin in the relatively healthy centenarians as compared to a younger but pathological population. They also show that the plasma fibronectin of the investigated centenarians was better protected f rom proteolytic degradation than in the geriatric population. The above res ults also confirm the contention that epigenetic mechanisms such as an age- dependent increase of fibronectin synthesis and degradation and the potenti al noxious effects of degradation products may well play an important role in the age-dependent decline of physiological functions. (C) 231 Elsevier S cience ireland Ltd. All rights reserved.