Safety and Efficacy of Intratracheal Recombinant Human Clara Cell Protein in a Newborn Piglet Model of Acute Lung Injury

Abstract

Despite the widespread use of exogenous surfactant, acute and chronic lung injury continues to be a major cause of morbidity in preterm infants. CC10 is a protein produced by Clara cells that inhibits phospholipase A 2 and has anti-inflammatory and antifibrotic properties. We studied whether intratracheal (IT) recombinant human Clara cell protein (rhCC10) could safely minimize lung injury in a newborn piglet model of acute lung injury. Twenty-nine newborn piglets were given Survanta and then ventilated for 48 h receiving the following: room air (group 1); 100% O 2 (group 2); or 100% O 2 and 25, 5, or 1 mg/kg (groups 3, 4, and 5, respectively) of IT rhCC10 (diluted to 2 mL/kg with saline) at time 0. Laboratory studies, oxygen ratios, static pressure-volume curves, bronchoalveolar lavage (for inflammatory markers), and histologic analyses were performed over the 48-h study period. Pulmonary compliance and oxygenation were significantly improved in animals receiving 5 mg/kg IT rhCC10 compared with room air and 100% O 2 controls (p Ͻ 0.004 and p Ͻ 0.05, respectively, ANOVA). Reductions in inflammatory markers were seen in animals receiving rhCC10, although changes did not reach statistical significance. No significant toxicity was noted. rhCC10 appeared safe and improved pulmonary function in this newborn piglet model of hyperoxic lung injury. We speculate that rhCC10 may represent a promising therapy for the prevention of lung injury in preterm infants. Bronchopulmonary dysplasia continues to be a significant problem for the preterm infant despite improvements in neonatal intensive care. Although the use of antenatal steroids and exogenous surfactant has resulted in decreased severity of BPD, the prevalence of BPD in the preterm population has actually increased. BPD is a multifactorial disease process that is the end result of an immature, surfactant-deficient lung that has been exposed to hyperoxia, mechanical volutrauma, and infection. These forces initiate a cascade of pro-inflammatory cytokines that lead to the development of significant inflammatory changes and chronic lung injury.CC10 is produced by the nonciliated cells of the tracheobronchial epithelial tree and is thought to have numerous anti-inflammatory properties. It has been shown to play a significant role, both in vitro and in vivo, in modulating inflammation (1-5). CC10, also known as uteroglobin, inhibits sPLA 2 (2, 6), an enzyme that degrades surfactant and facilitates prostaglandin biosynthesis (through the cleavage of arachidonic acid from cell membrane phospholipids). In vitro, CC10 has been shown to inhibit neutrophil and phagocyte chemotaxis (3) and IL-stimulated release of numerous cytokines in human blood lymphocytes (tumor necrosis factor-␣, IL-1␤, and interferon-␥) (4). CC10 also inhibits the formation of the proinflammatory fibronectin/IgA complex that may mitigate fibrotic changes in the lung (7). Further in vivo evidence of these ABSTRACT509

CC10 Reduces Inflammation in Meconium Aspiration Syndrome in Newborn Piglets

“…rhCC10 (5 mg/kg diluted to a total volume of 2 mL/kg with normal saline) was instilled with the piglets in a 30-degree Trendelenberg (head-down) position in two divided doses in the left and right lateral decubitus positions. The rhCC10 was produced in Escherichia coli bacteria according to published methods (Claragen, Inc., Germantown, MD) (15). The protein for the study was a Ͼ98% pure solution of the human CC10 homodimer.…”

“…The protein for the study was a Ͼ98% pure solution of the human CC10 homodimer. The biologic activity of each batch was compared using a previously published secretory PLA 2 inhibition assay for rhCC10 (15).…”

“…At 24 h, piglets were given pentobarbital (30 mg/kg), and static pressure-volume curves were generated as previously described (15). Two piglets in each group were used for histologic analysis.…”

“…Neutrophils were isolated from unventilated control pigs, and neutrophil chemotaxis assays (NCAs) were performed as previously described (15). The concentration of total protein in BAL fluid was quantified using the Pierce bicinchoninic acid (BCA) microtiter technique (16).…”

Advances in emerging treatment options to prevent bronchopulmonary dysplasia

“…Transgenic mice deficient in CCSP have been demonstrated to have exaggerated pulmonary inflammatory responses to hyperoxia and higher mortality rates [59]. Intra-tracheal treatment with exogenous CCSP tended to improve gas exchange and lung compliance in newborn piglets exposed to a hyperoxic injury [60]. A study in a premature lamb model found that treatment with synthetic recombinant human Clara cell secretory protein (rhCC10), increased surfactant protein and VEGF levels [61].…”