ALTERATIONS IN NONHUMAN PRIMATE (MACACA-NEMESTRINA) LUNG PROTEOGLYCANS DURING NORMAL DEVELOPMENT AND ACUTE HYALINE-MEMBRANE DISEASE

Proteoglycans (PGs) and lung hyaluronan (HA) are important components of the lung matrix both during normal development and in response to i njury. We combined morphologic and biochemical techniques to study cha nges in PG and HA in a developmental series of Macaca nemestrina lungs ranging from 62 % gestation to 3 mo post-term (n = 16), in adult lung s (n = 6), and from prematurely delivered, mechanically ventilated mon keys with hyaline membrane disease (HMD) (n = 7). Three groups of cupr olinic blue-positive (CuB) precipitates, identified by size, location, and susceptibility to enzyme digestion were found in lungs from all a nimals. Immature alveolar interstitium is characterized by loosely wov en collagen bundles and an abundance of large (100 to 200 nm) stained filaments representing chondroitin sulfate proteoglycans (CSPGs). As m aturation proceeds, the interstitial matrix appears increasingly organ ized, with large collagen bundles associated with 20 rim CuB-stained d eposits (dermatan sulfate proteoglycans, DSPGs), and fewer large CSPGs . Fetal alveolar basement membrane contains CuB-stained heparan sulfat e proteoglycans (HSPGs) (10 nm) scattered throughout. Lung matrix from animals with HMD appeared to have a disruption of the collagen-DSPG r elationship, in addition to an enrichment in large CSPG. Complementary biochemical analysis of lung PGs and HA was done. Minced lung parench yma was cultured with [H-3]-glucosamine and [S-35]-sulfate for 24 h; P Gs and HA were extracted and analyzed. While PG synthesis during devel opment tended to be highest at 80% gestation, animals with HMD showed greatly increased synthesis, approximately 2.5-fold higher than compar able fetal animals. In the developmental series, [H-3]-glucosamine inc orporation into HA was maximal at term, falling abruptly thereafter. H MD animals, however, showed a 2.3-fold increase over controls in net H A synthesis. Extracted PGs were separated according to buoyant density by dissociative cesium chloride density gradient ultracentrifugation. Two peaks of S-35-labeled PGs were separated from each density gradie nt fraction by chromatography on Sepharose CL-4B. A large CSPG was the principal PG eluting in the voiding volume, while the second broad pe ak (K(av) = 0.42) contained a mixed population of CSPG, DSPG, and HSPG s, the proportions of which varied with age. Both ultrastructural and biochemical analyses indicate that production of a large, high buoyant density CSPG predominates in fetal lung tissue, and diminishes with d evelopmental age. Synthesis of large CSPG is greatly increased in lung explants from prematurely delivered animals with HMD. These results d emonstrate that specific changes in the synthesis of matrix PGs occur during normal lung development and that the synthesis of these macromo lecules is further modulated in the lungs of animals with HMD.