Acid mucopolysaccharides and atherosclerosis

Acidic glycosaminoglycan, lipid and water contents in human coronary arterial branches

The acidic glycosaminoglycans (AGAG) of the human coronary arterial tree (the main left and right branches and their distal portions) were analyzed by enzymatic methods employing chondroitinases, hyaluronidase and heparitinase. The AGAG content of human coronary arteries was highest in the left branch, intermediate in the right branch and lowest in the distal portions. Some compositional differences in AGAG were found in these three parts. The amount of AGAG in the coronary arterial tree decreased with increasing severity of atherosclerosis. The main AGAG were heparan sulfate (HS) and chondroitin 6-sulfate (C-6S), constituting 33-38% and 24-36% of the total AGAG, respectively. Dermatan sulfate (DS) and chondroitin 4-sulfate (C-4S) each comprised 1/5-1/10 of the total AGAG. Hyaluronic acid (HA) and oversulfated DS comprised smaller proportions of the total AGAG. A small amount of heparin was occasionally detected in the coronary arterial tree, particularly in the distal portions. The lipid content of the main branches was increased in mildly atherosclerotic parts but diminished in severely affected parts. The water content was relatively higher in the main branches and decreased with severity of atherosclerosis. A possible function of these AGAG in atherosclerosis is discussed with respect to the compositional changes.

Arterial connective tissue changes and distribution of 125I-labelled low density lipoprotein in hypertensive pigs

Young pigs with hypertension of 10 weeks duration, resulting from cellophane perinephritis, were injected with 125I-labelled low-density lipoprotein ([125I]LDL) before being killed 24 h or 48 h later. Intimal thickening and increased acid mucopolysaccharide were demonstrated in the aortas and major arteries of the hypertensive animals. Increased accumulation of [125I]LDL was observed in the inner media beneath areas of intimal thickening. It is suggested that the primary effect of hypertension in atherosclerosis is to produce structural changes in arterial connective tissue which allow increased accumulation of LDL by altering the permeability and binding properties of the arterial wall.

Composition of acidic glycosaminoglycans in human cerebral arteries

(1) The composition of acidic glycosaminoglycans (AGAG) in the pooled human cerebral arteries was investigated by electrophoretic characterization before and after digestion with chondroitinases. Constitution of the chondroitin sulfate (CS) family was determined qualitatively on the basis of the disaccharide subunits of the CS chains after depolymerization with the enzymes. (2) The data obtained indicated that the AGAG in cerebral arteries consisted of, in order of amount, heparan sulfates, chondroitin-6-sulfate, dermatan sulfate, chondroitin-4-sulfate and hyaluronic acid. (3) The existence of oversulfated CS and undersulfated CS in the cerebral AGAG was supported by the detection of unsaturated di-sulfated and non-sulfated disaccharides on paper chromatography. In addition, the presence of hyaluronic acid was indicated by electrophoretic and enzymatic separation. (4) The distribution of the individual AGAG in cerebral arteries was also examined on the basis of molecular weight by gel filtration on a Sephadex G-100 column.