Surfactant proteins B and C are both necessary for alveolar stability at end expiration in premature rabbits with respiratory distress syndrome.
Modified natural surfactant preparations, used for treatment of respiratory distress syndrome in premature infants, contain phospholipids and the hydrophobic surfactant protein (SP)-B and SP-C. Herein, the individual and combined effects of SP-B and SP-C were evaluated in premature rabbit fetuses treated with airway instillation of surfactant and ventilated without positive end-expiratory pressure. Artificial surfactant preparations composed of synthetic phospholipids mixed with either 2% (wt/wt) of porcine SP-B, SP-C, or a synthetic poly-Leu analog of SP-C (SP-C33) did not stabilize the alveoli at the end of expiration, as measured by low lung gas volumes of approximately 5 ml/kg after 30 min of ventilation. However, treatment with phospholipids containing both SP-B and SP-C/SP-C33 approximately doubled lung gas volumes. Doubling the SP-C33 content did not affect lung gas volumes. The tidal volumes were similar in all groups receiving surfactant. This shows that SP-B and SP-C exert different physiological effects, since both proteins are needed to establish alveolar stability at end expiration in this animal model of respiratory distress syndrome, and that an optimal synthetic surfactant probably requires the presence of mimics of both SP-B and SP-C.
Almlén
Andreas
A
Dept. of Molecular Medicine and Surgery, Section of Clinical Chemistry, Bldg. L2:03, Karolinska Univ. Hospital, SE-171 76 Stockholm, Sweden.
Stichtenoth
Guido
G
Linderholm
Bim
B
Haegerstrand-Björkman
Marie
M
Robertson
Bengt
B
Johansson
Jan
J
Curstedt
Tore
T
D015060:1,2-Dipalmitoylphosphatidylcholine / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008176:Lung Volume Measurements; D008969:Molecular Sequence Data; D010743:Phospholipids / Q000378:metabolism; D011175:Positive-Pressure Respiration; D011247:Pregnancy; D011650:Pulmonary Alveoli / Q000502:physiology*; D037701:Pulmonary Surfactant-Associated Protein B / Q000502:physiology*; D037721:Pulmonary Surfactant-Associated Protein C / Q000502:physiology*; D011663:Pulmonary Surfactants / Q000494:pharmacology; D011817:Rabbits; D012127:Respiratory Distress Syndrome, Newborn / Q000503:physiopathology*; D015656:Respiratory Mechanics / Q000502:physiology; D013990:Tidal Volume / Q000502:physiology
D010743:Phospholipids; D037701:Pulmonary Surfactant-Associated Protein B; D037721:Pulmonary Surfactant-Associated Protein C; D011663:Pulmonary Surfactants; D015060:1,2-Dipalmitoylphosphatidylcholine