BMDMC therapy was effective at modulating the inflammatory and fibrogenic processes in both acute lung injury models; however, survival and lung mechanics and histology improved more in ALIexp. These changes may be attributed to paracrine effects balancing pro- and anti-inflammatory cytokines and growth factors, because a small degree of pulmonary BMDMC engraftment was observed.

We hypothesized that bone marrow-derived mononuclear cells (BMDMC) would attenuate the remodeling process in a chronic allergic inflammation model. C57BL/6 mice were assigned to two groups. In OVA, mice were sensitized and repeatedly challenged with ovalbumin. Control mice (C) received saline under the same protocol. C and OVA were further randomized to receive BMDMC (2 × 10⁶) or saline intravenously 24 h before the first challenge. BMDMC therapy reduced eosinophil infiltration, smooth muscle-specific actin expression, subepithelial fibrosis, and myocyte hypertrophy and hyperplasia, thus causing a decrease in airway hyperresponsiveness and lung mechanical parameters. BMDMC from green fluorescent protein (GFP)-transgenic mice transplanted into GFP-negative mice yielded lower engraftment in OVA. BMDMC increased insulin-like growth factor expression, but reduced interleukin-5, transforming growth factor-β, platelet-derived growth factor, and vascular endothelial growth factor mRNA expression. In conclusion, in the present chronic allergic inflammation model, BMDMC therapy was an effective pre-treatment protocol that potentiated airway epithelial cell repair and prevented inflammatory and remodeling processes.

There is evidence that sex and sex hormones influence the severity of asthma. Airway and lung parenchyma remodeling and the relationship of ultrastructural changes to airway responsiveness and inflammation in male, female, and oophorectomized mice (OVX) were analyzed in experimental chronic allergic asthma. Seventy-two BALB/c mice were randomly divided into three groups (n=24/each): male, female, and OVX mice, whose ovaries were removed 7 days before the start of sensitization. Each group was further randomized to be sensitized and challenged with ovalbumin (OVA) or saline. Twenty-four hours after the last challenge, collagen fiber content in airways and lung parenchyma, the volume proportion of smooth muscle-specific actin in alveolar ducts and terminal bronchiole, the amount of matrix metalloproteinase (MMP)-2 and MMP-9, and the number of eosinophils and interleukin (IL)-4, IL-5, and transforming growth factor (TGF)-β levels in bronchoalveolar lavage fluid were higher in female than male OVA mice. The response of OVX mice was similar to that of males, except that IL-5 remained higher. Nevertheless, after OVA provocation, airway responsiveness to methacholine was higher in males compared with females and OVX mice. In conclusion, sex influenced the remodeling process, but the mechanisms responsible for airway hyperresponsiveness seemed to differ from those related to remodeling.

We hypothesized that the route of administration would impact the beneficial effects of bone marrow-derived mononuclear cell (BMDMC) therapy on the remodelling process of asthma. C57BL/6 mice were randomly assigned to two main groups. In the OVA group, mice were sensitized and challenged with ovalbumin, while the control group received saline using the same protocol. Twenty-four hours before the first challenge, control and OVA animals were further randomized into three subgroups to receive saline (SAL), BMDMCs intravenously (2×10(6)), or BMDMCs intratracheally (2×10(6)). The following changes were induced by BMDMC therapy in OVA mice regardless of administration route: reduction in resistive and viscoelastic pressures, static elastance, eosinophil infiltration, collagen fibre content in airways and lung parenchyma; and reduction in the levels of interleukin (IL)-4, IL-13, transforming growth factor-β and vascular endothelial growth factor. In conclusion, BMDMC modulated inflammatory and remodelling processes regardless of administration route in this experimental model of allergic asthma.

Recently, several reports suggest differences in the vascularization of the various histopathologic patterns of parenchymal remodeling seen in usual interstitial pneumonia (UIP). In this study, we sought to validate the importance of vascular remodeling in patients with idiopathic pulmonary fibrosis (IPF) and to examine the relationship between vascular remodeling and parenchymal remodeling or pulmonary function. Open lung biopsies were performed in 57 patients with IPF, and vascular changes in alternating areas of parenchymal remodeling (UIP histologic patterns) were studied. Quantitative analysis of the internal area, internal perimeter, wall thickness, and surrounding cellularity of medium or large pulmonary arteries, as well as their distribution according to air/parenchymal ratios, was performed. Semiquantitative analysis also was used to determine the grade of vascular occlusion. An inverse association was found between vascularization and UIP parenchymal remodeling (p < 0.05); that is, the decreased internal luminal area and perimeter as well as the increased wall thickness run in parallel with progression from alveolar collapse toward severe mural-organizing fibrosis with honeycombing. Vascular regression (diminished internal area and perimeter of vessels) was also associated with higher FEV(1), FVC, and RV values (r = 0.48, p< 0.05), reflecting a tight relationship between vascular remodeling and pulmonary function. A progressive regression of vascularization, reflected by different degrees of luminal occlusion after vascular remodeling, coincided with parenchymal remodeling (alveolar collapse, mural-organizing fibrosis, and honeycombing). This vascular regression may be responsible for the impaired wound healing and progressive fibroproliferation found in patients with IPF. Further studies are needed to determine whether this relationship is causal or consequential.