Browsing by Author "Montalva, Rebeca"

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    Acute lung injury induced by whole gastric fluid: hepatic acute phase response contributes to increase lung antiprotease protection
    (2016) Ayala, Pedro; Meneses, Manuel; Olmos Coelho, Pablo Roberto; Montalva, Rebeca; Droguett Quezada, Karla Denise.; Rios Raggio, Mariana; Borzone, Gisella
    Abstract Background Gastric contents aspiration in humans is a risk factor for severe respiratory failure with elevated mortality. Although aspiration-induced local lung inflammation has been studied in animal models, little is known about extrapulmonary effects of aspiration. We investigated whether a single orotracheal instillation of whole gastric fluid elicits a liver acute phase response and if this response contributes to enrich the alveolar spaces with proteins having antiprotease activity. Methods In anesthetized Sprague-Dawley rats receiving whole gastric fluid, we studied at different times after instillation (4 h −7 days): changes in blood cytokines and acute phase proteins (fibrinogen and the antiproteases alpha1-antitrypsin and alpha2-macroglobulin) as well as liver mRNA expression of the two antiproteases. The impact of the systemic changes on lung antiprotease defense was evaluated by measuring levels and bioactivity of antiproteases in broncho-alveolar lavage fluid (BALF). Markers of alveolar-capillary barrier derangement were also studied. Non-parametric ANOVA (Kruskall-Wallis) and linear regression analysis were used. Results Severe peribronchiolar injury involving edema, intra-alveolar proteinaceous debris, hemorrhage and PMNn cell infiltration was seen in the first 24 h and later resolved. Despite a large increase in several lung cytokines, only IL-6 was found elevated in blood, preceding increased liver expression and blood concentration of both antiproteases. These changes, with an acute phase response profile, were significantly larger for alpha2-macroglobulin (40-fold increment in expression with 12-fold elevation in blood protein concentration) than for alpha1-antitrypsin (2–3 fold increment in expression with 0.5-fold elevation in blood protein concentration). Both the increment in capillary-alveolar antiprotease concentration gradient due to increased antiprotease liver synthesis and a timely-associated derangement of the alveolar-capillary barrier induced by aspiration, contributed a 58-fold and a 190-fold increase in BALF alpha1-antitrypsin and alpha2-macroglobulin levels respectively (p < 0.001). Conclusions Gastric contents-induced acute lung injury elicits a liver acute phase response characterized by increased mRNA expression of antiproteases and elevation of blood antiprotease concentrations. Hepatic changes act in concert with derangement of the alveolar capillary barrier to enrich alveolar spaces with antiproteases. These findings may have significant implications decreasing protease burden, limiting injury in this and other models of acute lung injury and likely, in recurrent aspiration.
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    Elastin degradation products in acute lung injury induced by gastric contents aspiration
    (2018) Ayala, Pedro; Vivar, Raúl; Montalva, Rebeca; Olmos Coelho, Pablo Roberto; Borzone, Gisella; Meneses, Manuel
    Abstract Background Gastric contents aspiration is a high-risk condition for acute lung injury (ALI). Consequences range from subclinical pneumonitis to respiratory failure, depending on the volume of aspirate. A large increment in inflammatory cells, an important source of elastase, potentially capable of damaging lung tissue, has been described in experimental models of aspiration. We hypothesized that in early stages of aspiration-induced ALI, there is proteolytic degradation of elastin, preceding collagen deposition. Our aim was to evaluate whether after a single orotracheal instillation of gastric fluid, there is evidence of elastin degradation. Methods Anesthesized Sprague-Dawley rats received a single orotracheal instillation of gastric fluid and were euthanized 4, 12 and 24 h and at day 4 after instillation (n = 6/group). We used immunodetection of soluble elastin in lung tissue and BALF and correlated BALF levels of elastin degradation products with markers of ALI. We investigated possible factors involved in elastin degradation and evaluated whether a similar pattern of elastin degradation can be found in BALF samples of patients with interstitial lung diseases known to have aspirated. Non-parametric ANOVA (Kruskall-Wallis) and linear regression analysis were used. Results We found evidence of early proteolytic degradation of lung elastin. Elastin degradation products are detected both in lung tissue and BALF in the first 24 h and are significantly reduced at day 4. They correlate significantly with ALI markers, particularly PMN cell count, are independent of acidity and have a similar molecular weight as those obtained using pancreatic elastase. Evaluation of BALF from patients revealed the presence of elastin degradation products not present in controls that are similar to those found in BALF of rats treated with gastric fluid. Conclusions A single instillation of gastric fluid into the lungs induces early proteolytic degradation of elastin, in relation to the magnitude of alveolar-capillary barrier derangement. PMN-derived proteases released during ALI are mostly responsible for this damage. BALF from patients showed elastin degradation products similar to those found in rats treated with gastric fluid. Long-lasting effects on lung elastic properties could be expected under conditions of repeated instillations of gastric fluid in experimental animals or repeated aspiration events in humans.
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    Osteoclastogenesis in Patients With Systemic Sclerosis With and Without Calcinosis Cutis
    (Wiley, 2025) Valenzuela Vergara, Antonia María; Pérez, Guillermo; Chung, Lorinda; Sánchez, Felipe; Iturriaga Ortiz, Carolina Alejandra; Montalva, Rebeca; Borzutzky Schachter, Arturo
    Objective. We aimed to assess whether the presence of radiographically confirmed calcinosis of the hands in patients with systemic sclerosis (SSc) is associated with increased osteoclastogenesis. Methods. We recruited 20 patients with SSc (10 with calcinosis and 10 without calcinosis) and 10 age- and gender-matched healthy controls. Hand radiographs were scored using the validated Scleroderma Clinical Trials Consortium (SCTC) radiographic severity score for calcinosis. To evaluate osteoclastogenesis, peripheral blood mononuclear cells (PBMCs) were cultured with RANKL and macrophage colony-stimulating factor; osteoclasts were identified using tartrate-resistant acid phosphatase staining. Measures of bone resorption (RANKL, osteoprotegerin [OPG]) and ischemia or endothelial function (vascular endothelial growth factor, angiopoietin-1, and angiopoietin-2 [Ang-2]) were also evaluated. Results. Patients with SSc were all women and Hispanic, and the majority (n = 12, 60%) had limited SSc skin type. Mean +/- SD age was 55.2 +/- 14.8 years; mean +/- SD disease duration was 9.5 +/- 6.5 years from first non-Raynaud phenomenon symptom. Patients with SSc with calcinosis had more digital ischemia than patients without calcinosis. Median SCTC score in patients with SSc with calcinosis was 11.1 (range 0.7-286). After 9 days in culture, PBMCs from patients with calcinosis originated a significantly higher number of osteoclasts (33.0 +/- 20.3 cells/well) than patients without calcinosis (15.3 +/- 6.9 cells/well) and healthy individuals (11.2 +/- 2.6 cells/well) (P = 0.001). The severity of calcinosis was not correlated with the number of osteoclasts per well (r = 0.27, P = 0.5); however, it was correlated with RANKL (r = 0.82, P = 0.004), RANKL/OPG ratio (r = 0.86, P = 0.002), and Ang-2 levels (r = 0.86, P = 0.002). Conclusion. Calcinosis in patients with SSc is associated with an increased propensity of peripheral blood cells to form osteoclasts. Targeted inhibition of osteoclastogenesis may provide a specific therapeutic option for patients with SSc-associated calcinosis.