desmosine and Hyaline-Membrane-Disease

We correlated clinical, biochemical, and morphologic findings in the lungs of 48 infants dying of either bronchopulmonary dysplasia (BPD) or hyaline membrane disease (HMD) to obtain a better idea of the disease process. The infants ranged from 24 weeks of gestation to 1 1/2 postnatal years. The lungs of BPD and HMD infants had higher contents of DNA, alkalisoluble protein, hydroxyproline, and desmosine, as well as increased concentrations of DNA, hydroxyproline, and desmosine when compared with the lungs of 72 control infants. BPD was classified histologically into 4 groups: Group I was a phase of acute lung injury, Group II the proliferative phase; Group III the phase of early repair, and Group IV the phase of late repair. We saw a significant increase in hydroxyproline concentration in Groups II and III. The ratio of type I/III collagen decreased in BPD Groups II to IV. Desmosine was significantly higher only in Group III than in controls. When the pathological classification was related to biochemical and clinical features of BPD, the classification showed dependence on the number of days the infant survived postnatally and not on the gestational age of the infant. The number of days on assisted ventilation was a slightly better predictor of the disease classification than days on > 60% oxygen. A statistical model correctly predicted the pathologic classification 83% of the time.

Topics: Bronchopulmonary Dysplasia; Case-Control Studies; Collagen; Desmosine; DNA; Humans; Hyaline Membrane Disease; Hydroxyproline; Infant; Infant, Newborn; Lung

Desmosine has been quantitated in the normally grown fetal and early infant lung by radioimmunoassay. Desmosine could first be detected at 22 weeks gestation: the concentration of desmosine expressed per milligram lung DNA increased in approximately linear form up to about 55 weeks postconceptional age. The concentration in peripheral lung was approximately half that in whole lung homogenates. Lungs of infants dying with acute HMD and lungs of growth retarded infants showed no significant differences from the normals, although there was a tendency for higher desmosine concentrations in prematurely born growth retarded infants.

Topics: Amino Acids; Desmosine; Elastin; Fetus; Humans; Hyaline Membrane Disease; Infant, Newborn; Lung; Radioimmunoassay

The effects of preterm birth and mechanical ventilation on growth of the alveolar region of the lung were assessed by morphometric and/or quantitative biochemical methods in the lungs from 104 perinatal and infant autopsies. The lungs of 4 preterm infants who died at 4-16 weeks age without having received mechanical ventilation were large relative to body weight but showed normal alveolar number and alveolar surface area. Infants treated by mechanical ventilation for hyaline membrane disease (HMD) and who died at ages from 1 week up to 14 months showed impairment in alveolar development evidenced by low alveolar number and a low alveolar surface area. Lung volume and total lung DNA values were relatively normal. Dilated alveolar ducts were a feature at all ages with emphysematous changes apparent in the longest surviving infants. Biochemical features included a high concentration of hydroxyproline, reflecting collagen, and a high desmosine concentration, reflecting elastin, in infants dying at less than 60 weeks postconceptional age. Changes in the lungs of infants ventilated at low pressures for conditions other than HMD were of a similar nature but less severe than those seen in the HMD group. These findings indicate that preterm birth alone may have little adverse influence on lung development but that conditions necessitating mechanical ventilation may lead to permanent impairment in alveolar development. We postulate that the standard technique of applying positive pressure ventilation may itself lead to impaired alveolar growth, although the effect is enhanced by concomitant HMD and BPD.

Topics: Apnea; Asphyxia Neonatorum; Collagen; Desmosine; DNA; Elastin; Humans; Hyaline Membrane Disease; Hydroxyproline; Infant; Infant, Newborn; Infant, Premature; Lung; Pulmonary Alveoli; Respiration, Artificial