Luiz Felipe M Prota

Universidade Federal do Espírito Santo, Victoria, Espírito Santo, Brazil

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Publications (12)31.08 Total impact

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    ABSTRACT: Malnutrition is a risk factor for infection, compromising immune response. Glutamine (Gln) protects the lungs and distal organs in well-nourished septic and non-septic conditions; however, no study to date has analyzed the effects of glutamine in the presence of sepsis and malnutrition. In the present work, we tested the hypothesis that early therapy with intravenous Gln prevents lung and distal organ damage in septic malnourished rats. Protein-energy malnutrition was induced in male Wistar rats for 4 weeks. At the end of 4 weeks, malnourished animals were assigned to a sepsis-inducing cecal ligation and puncture (CLP) group or a Sham surgery group. One hour after surgery, animals were given saline (Sal) or L-alanyl-L-glutamine (Gln) intravenously. In addition, a control group (C) was set up with rats fed ad libitum, not submitted to surgery or treatment. Forty-eight hours after surgery, in Malnutrition-Sham rats, Gln therapy lessened neutrophil lung infiltration and apoptosis in lung and liver. In Malnutrition-CLP rats, Gln therapy yielded: 1) reduced static lung elastance, alveolar collapse, inflammation (neutrophil infiltration, interleukin-6), and collagen deposition; 2) repair of types I and II epithelial cells; 3) no significant changes in heat shock protein (HSP) 70 expression or heat shock factor (HSF)-1 phosphorylation; 4) a greater number of M1 and M2 macrophages in lung tissue; and 5) less apoptosis in the lung, kidney, small intestine, and liver. In conclusion, early therapy with intravenous Gln reduced inflammation, fibrosis, and apoptosis, minimizing lung and distal organ injury, in septic malnourished rats. These beneficial effects may be associated with macrophage activation in the lung.
    Shock (Augusta, Ga.) 01/2014; · 2.87 Impact Factor
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    ABSTRACT: Dexamethasone is widely used for pulmonary exacerbation in patients with cystic fibrosis, however, not much is known about the effects of glucocorticoids on the wild-type cystic fibrosis channel transmembrane regulator (CFTR). Our aim was to determine the effects of dexamethasone treatment on wild-type CFTR expression. Dose-response (1 nM to 10 µM) and time course (3 to 48 h) curves were generated for dexamethasone for mRNA expression in Calu-3 cells using a real-time PCR. Within 24 h, dexamethasone (10 nM) showed a 0.3-fold decrease in CFTR mRNA expression, and a 3.2-fold increase in αENaC mRNA expression compared with control groups. Dexamethasone (10 nM) induced a 1.97-fold increase in the total protein of wild-type CFTR, confirmed by inhibition by mifepristone. To access surface protein expression, biotinylation followed by Western blotting showed that dexamethasone treatment led to a 2.35-fold increase in the amount of CFTR in the cell surface compared with the untreated control groups. Once protein translation was inhibited with cycloheximide, dexamethasone could not increase the amount of CFTR protein. Protein stability was assessed by inhibition of protein synthesis with cycloheximide (50 µg/ml) at different times in cells treated with dexamethasone and in untreated cells. Dexamethasone did not alter the degradation of wild-type CFTR. Assessment of the B band of CFTR within 15 min of metabolic pulse labeling showed a 1.5-fold increase in CFTR protein after treatment with dexamethasone for 24 h. Chaperone 90 (HSP90) binding to CFTR increased 1.55-fold after treatment with dexamethasone for 24 h, whereas chaperone 70 (HSP70) binding decreased 0.30 fold in an immunoprecipitation assay. Mature wild-type CFTR protein is regulated by dexamethasone post transcription, involving cotranslational mechanisms with HSP90 and HSP70, which enhances maturation and expression of wild-type CFTR.
    PLoS ONE 12/2012; 7(12):e47405. · 3.53 Impact Factor
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    ABSTRACT: The steroid hormones, estrogen and progesterone, are involved mainly in the control of female reproductive functions. Among other effects, estrogen and progesterone can modulate Na(+) reabsorption along the nephron altering the body's hydroelectrolyte balance. In this work, we analyzed the expression of cyclic nucleotide-gated channel A1 (CNG-A1) and α1 Na(+)/K(+)-ATPase subunit in the renal cortex and medulla of female ovariectomized rats and female ovariectomized rats subjected to 10 days of 17β-estradiol benzoate (2.0 µg/kg body weight) and progesterone (1.7 mg/kg body weight) replacement. Na(+)/K(+) ATPase activity was also measured. Immunofluorescence localization of CNG-A1 in the cortex and medulla was performed in control animals. We observed that CNG-A1 is localized at the basolateral membrane of proximal and distal tubules. Female ovariectomized rats showed low expression of CNG-A1 and low expression and activity of Na(+)/K(+) ATPase in the renal cortex. When female ovariectomized rats were subjected to 17β-estradiol benzoate replacement, normalization of CNG-A1 expression and Na(+)/K(+) ATPase expression and activity was observed. The replacement of progesterone was not able to recover CNG-A1 expression and Na(+)/K(+) ATPase expression at the control level. Only the activity of Na(+)/K(+) ATPase was able to be recovered at control levels in animals subjected to progesterone replacement. No changes in expression and activity were observed in the renal medulla. The expression of CNG-A1 is higher in cortex compared to medulla. In this work, we observed that estrogen and progesterone act in renal tissues modulating CNG-A1 and Na(+)/K(+) ATPase and these effects could be important in Na(+) and water balance.
    Cellular Physiology and Biochemistry 01/2012; 30(1):160-72. · 3.55 Impact Factor
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    ABSTRACT: Lung mechanics, histology, oxygenation and type-III procollagen (PCIII) mRNA were studied aiming to evaluate the need to readjust ventilatory pattern when going from two- to one-lung ventilation (OLV). Wistar rats were assigned to three groups: the left lung was not ventilated while the right lung received: (1) tidal volume (V(T))=5 ml/kg and positive end-expiratory pressure (PEEP)=2 cm H(2)O (V5P2), (2) V(T)=10 ml/kg and PEEP=2 cm H(2)O (V10P2), and (3) V(T)=5 ml/kg and PEEP=5 cm H(2)O (V5P5). At 1-h ventilation, V5P2 showed hypoxemia, alveolar collapse and impaired lung function. Higher PEEP minimized these changes and prevented hypoxemia. Although high V(T) prevented hypoxemia and maintained a higher specific compliance than V5P2, a morphologically inhomogeneous parenchyma and higher PCIII expression resulted. In conclusion, the association of low V(T) and an adequate PEEP level could be useful to maintain arterial oxygenation without inducing a possible inflammatory/remodeling response.
    Respiratory Physiology & Neurobiology 08/2011; 179(2-3):198-204. · 1.97 Impact Factor
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    ABSTRACT: The aim of this study was to test the hypothesis that bone marrow mononuclear cell (BMDMC) therapy led an improvement in lung mechanics and histology in endotoxin-induced lung injury. Twenty-four C57BL/6 mice were randomly divided into four groups (n = 6 each). In the acute lung injury (ALI) group, Escherichia coli lipopolysaccharide (LPS) was instilled intratracheally (40 μg, IT), and control (C) mice received saline (0.05 ml, IT). One hour after the administration of saline or LPS, BMDMC (2 × 10(7) cells) was intravenously injected. At day 28, animals were anesthetized and lung mechanics [static elastance (E(st)), resistive (ΔP(1)), and viscoelastic (ΔP(2)) pressures] and histology (light and electron microscopy) were analyzed. Immunogold electron microscopy was used to evaluate if multinucleate cells were type II epithelial cells. BMDMC therapy prevented endotoxin-induced lung inflammation, alveolar collapse, and interstitial edema. In addition, BMDMC administration led to epithelial and endothelial repair with multinucleated type II pneumocytes. These histological changes yielded a reduction in lung E(st), ΔP(1), and ΔP(2) compared to ALI. In the present experimental ALI model, the administration of BMDMC yielded a reduction in the inflammatory process and a repair of epithelium and endothelium, reducing the amount of alveolar collapse, thus leading to an improvement in lung mechanics.
    Cell Transplantation 05/2010; 19(8):965-71. · 3.57 Impact Factor
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    ABSTRACT: The time course of lung mechanics, histology, and inflammatory and fibrogenic mediators are analysed after intratracheal instillation (IT) of bone marrow-derived cells (BMDC) in a model of silicosis. C57BL/6 mice were randomly divided into SIL (silica, 20mg IT) and control (CTRL) groups (saline IT). At day 15, mice received saline or BMDC (2 x 10(6)cells) IT. The biodistribution of technetium-99m BMDC was higher in lungs compared with other organs. At days 30 and 60, lung mechanics, the area of granulomatous nodules, and mRNA expression of IL-1beta and TGF-beta were higher in SIL than CTRL animals. BMDC minimized changes in lung mechanics, the area of granulomatous nodules, and total cell infiltration at day 30, but these effects were no longer observed at day 60. Conversely, BMDC avoided the expression of IL-1beta at days 30 and 60 and TGF-beta only at day 30. In conclusion, BMDC therapy improved lung mechanics and histology, but this beneficial effect was not maintained in the course of injury.
    Respiratory Physiology & Neurobiology 09/2009; 169(3):227-33. · 1.97 Impact Factor
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    ABSTRACT: Prone position may delay the development of ventilator-induced lung injury (VILI), but the mechanisms require better elucidation. In experimental mild acute lung injury (ALI), arterial oxygen partial pressure (Pa O2), lung mechanics and histology, inflammatory markers [interleukin (IL)-6 and IL-1 beta], and type III procollagen (PCIII) mRNA expressions were analysed in supine and prone position. Wistar rats were randomly divided into two groups. In controls, saline was intraperitoneally injected while ALI was induced by paraquat. After 24-h, the animals were mechanically ventilated for 1-h in supine or prone positions. In ALI, prone position led to a better blood flow/tissue ratio both in ventral and dorsal regions and was associated with a more homogeneous distribution of alveolar aeration/tissue ratio reducing lung static elastance and viscoelastic pressure, and increasing end-expiratory lung volume and Pa O2. PCIII expression was higher in the ventral than dorsal region in supine position, with no regional changes in inflammatory markers. In conclusion, prone position may protect the lungs against VILI, thus reducing pulmonary stress and strain.
    Respiratory Physiology & Neurobiology 07/2009; 167(2):181-8. · 1.97 Impact Factor
  • American Thoracic Society 2009 International Conference, May 15-20, 2009 • San Diego, California; 04/2009
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    ABSTRACT: Uncertainties about the numerous degrees of freedom in ventilator settings leave many unanswered questions about the biophysical determinants of lung injury. We investigated whether mechanical ventilation with high air flow could yield lung mechanical stress even in normal animals. Prospective, randomized, controlled experimental study. University research laboratory. Thirty normal male Wistar rats (180-230 g). Rats were ventilated for 2 hrs with tidal volume of 10 mL/kg and either with normal inspiratory air flow (V') of 10 mL/s (F10) or high V' of 30 mL/s (F30). In the control group, animals did not undergo mechanical ventilation. Because high flow led to elevated respiratory rate (200 breaths/min) and airway peak inspiratory pressure (PIP,aw = 17 cm H2O), two additional groups were established to rule out the potential contribution of these variables: a) normal respiratory rate = 100 breaths/min and V' = 30 mL/sec; and b) PIP,aw = 17 cm H2O and V' = 10 mL/sec. Lung mechanics and histology (light and electron microscopy), arterial blood gas analysis, and type III procollagen messenger RNA expression in lung tissue were analyzed. Ultrastructural microscopy was similar in control and F10 groups. High air flow led to increased lung plateau and peak pressures, hypoxemia, alveolar hyperinflation and collapse, pulmonary neutrophilic infiltration, and augmented type III procollagen messenger RNA expression compared with control rats. The reduction of respiratory rate did not modify the morphofunctional behavior observed in the presence of increased air flow. Even though the increase in peak pressure yielded mechanical and histologic changes, type III procollagen messenger RNA expression remained unaltered. Ventilation with high inspiratory air flow may lead to high tensile and shear stresses resulting in lung functional and morphologic compromise and elevation of type III procollagen messenger RNA expression.
    Critical care medicine 02/2008; 36(1):232-9. · 6.15 Impact Factor
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    ABSTRACT: Physical forces affect both the function and phenotype of cells in the lung. Bronchial, alveolar, and other parenchymal cells, as well as fibroblasts and macrophages, are normally subjected to a variety of passive and active mechanical forces associated with lung inflation and vascular perfusion as a result of the dynamic nature of lung function. These forces include changes in stress (force per unit area) or strain (any forced change in length in relation to the initial length) and shear stress (the stress component parallel to a given surface). The responses of cells to mechanical forces are the result of the cell's ability to sense and transduce these stimuli into intracellular signaling pathways able to communicate the information to its interior. This review will focus on the modulation of intracellular pathways by lung mechanical forces and the intercellular signaling. A better understanding of the mechanisms by which lung cells transduce physical forces into biochemical and biological signals is of key importance for identifying targets for the treatment and prevention of physical force-related disorders.
    Brazilian Journal of Medical and Biological Research 07/2006; 39(6):697-706. · 1.03 Impact Factor
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    Brazilian Journal of Medical and Biological Research 06/2006; 39(6):697-706. · 1.03 Impact Factor
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    ABSTRACT: This study tests the hypotheses that a recruitment maneuver per se yields and/or intensifies lung mechanical stress. Recruitment maneuver was applied to a model of paraquat-induced acute lung injury (ALI) and to healthy rats with (ATEL) or without (CTRL) previous atelectasis. Recruitment was done by using 40-cmH(2)O continuous positive airway pressure for 40 s. Rats were, then, ventilated for 1 h at zero end-expiratory pressure (ZEEP) or positive end-expiratory pressure (PEEP; 5 cmH(2)O). Atelectasis was generated by inflating a sphygmomanometer around the thorax. Additional groups did not undergo recruitment but were ventilated for 1 h under ZEEP. Lung resistive and viscoelastic pressures and static elastance were computed before and immediately after recruitment, and at the end of 1 h of ventilation. Lungs were prepared for histology. Type III procollagen (PCIII) mRNA expression in lung tissue was analyzed by RT-PCR. Lung mechanics improved after recruitment in the CTRL and ALI groups. One hour of ventilation at ZEEP increased alveolar collapse, static elastance, and lung resistive and viscoelastic pressures. Alveolar collapse was similar in ATEL and ALI, and recruitment opened the alveoli in both groups. ALI showed higher PCIII expression than ATEL or CTRL groups. One hour of ventilation at ZEEP did not increase PCIII expression but augmented it significantly in the three groups when applied after recruitment. However, PEEP ventilation after recruitment avoided any increment in PCIII expression in all groups. In conclusion, recruitment followed by ZEEP was more deleterious in ALI than in mechanical ATEL, although ZEEP alone did not elevate PCIII expression. Ventilation with 5-cmH(2)O PEEP prevented derecruitment and aborted the increase in PCIII expression.
    Journal of Applied Physiology 02/2005; 98(1):53-61. · 3.43 Impact Factor