Plasma glycosaminoglycans in normal individuals of various age

Our previous studies have demonstrated that the high-sulfated glycosaminoglycans (GAG) of human plasma interact with low-density and high-density plasma lipoproteins (LDL and HDL), while the more abundant, low-sulfated plasma GAG prevent such interaction. Therefore, we have suggested that the ratio of these two species of circulating GAG might affect the rheological properties and metabolic fate of plasma lipoproteins. In this study the high-sulfated and low-sulfated plasma GAG have been measured in 79 normal individuals of both sexes, belonging to increasing age groups: 20–29, 30–39, 40–49 and 50–59 years old. No significant differences were found between males and females of the same group. No significant differences were found between the levels of high-sulfated and low-sulfated plasma GAG of the first and second group of individuals. The average values found and their ratios were in agreement with those reported previously for the same age groups. The average values of high-sulfated and low-sulfated plasma GAG of the third and fourth group of individuals were not statistically different but they were significantly higher than those of the first two groups. Moreover, the ratio high-sulfated/low-sulfated plasma GAG in older individuals was between 0.41 and 0.45, as compared to values of 0.27–0.37 found in the younger individuals. This increased ratio reflects a greater increase in the level of the high-sulfated species which, by interacting with circulating lipoproteins, might cause physical and metabolic modifications favoring their deposition and permanence within the arterial wall.