In the present study, we show that gestational but not early postnatal exposure of mice to secondhand cigarette smoke (SS) suppresses alveolarization, angiogenesis, and development of Clara and goblet cells without significant lung inflammation and that the SS-induced effects on alveolar architecture are irreversible.
Results from SS-exposed PD7 lungs from C57BL/6 mice (see Supplemental Material, Figure S1B) showed morphometric changes similar to those observed in BALB/c mice, thus indicating that both BALB/c and C57BL/6 mice develop impaired alveolarization in response to gestational SS.
We observed that while MM (an nAChR antagonist) treatment during gestational period alone did not significantly affect alveolarization and [L.
Together, these results suggest that decreased alveolarization in gestationally SS-exposed lung may reflect the reduction in angiogenesis that affects lung vascularization.
The researchers found that the intratracheal, rather than the intraperitoneal transplantation of human UCB-derived MSCs, significantly attenuated the hyperoxia-induced lung injury, such as decreased alveolarization
In addition, there are signs of impaired alveolarization
, such as thickened alveolar interstitial septae, a simplified alveolar pattern, and regenerative hyperplastic type II pneumocytes (1,2) (Figure 4).
In the second study, hyperoxia altered the development of neonatal rat lungs, inhibiting alveolarization
and vascularization and promoting epithelial to mesenchymal transition and hyperplasia.
Potential mechanisms of delayed effects include interference with highly conserved factors in developmental processes such as gene regulation, molecular signaling, and growth factors involved in branching morphogenesis and alveolarization
Potential mechanisms include interference with highly conserved factors in developmental processes such as gene regulation, molecular signaling, and growth factors involved in branching morphogenesis and alveolarization.
Only a portion of maturational events are required prenatally for successful survival, with most continuing postnatally during alveolarization (Pinkerton and Joad 2000).
During alveolarization, the primitive alveoli develop secondary septa that form the walls of the true alveoli, resulting in a dramatic increase in surface area.
During all that time, the lung undergoes alveolarization
and continued morphogenesis with a differentiation of most critical cell types and epithelial structures.