Mitochondria-Rich Fraction Isolated From Mesenchymal Stromal Cells Reduces Lung and Distal Organ Injury in Experimental Sepsis.

OBJECTIVES: To ascertain whether systemic administration of mitochondria-rich fraction isolated from mesenchymal stromal cells would reduce lung, kidney, and liver injury in experimental sepsis. DESIGN: Animal study. SETTING: Laboratory investigation. SUBJECTS: Sixty C57BL/6 male mice. INTERVENTIONS: Sepsis was induced by cecal ligation and puncture; sham-operated animals were used as control. At 24 hours after surgery, cecal ligation and puncture and Sham animals were further randomized to receive saline or mitochondria-rich fraction isolated from mesenchymal stromal cells (3 × 106) IV. At 48 hours, survival, peritoneal bacterial load, lung, kidney, and liver injury were analyzed. Furthermore, the effects of mitochondria on oxygen consumption rate and reactive oxygen species production of lung epithelial and endothelial cells were evaluated in vitro. MEASUREMENTS AND MAIN RESULTS: In vitro exposure of lung epithelial and endothelial cells from cecal ligation and puncture animals to mitochondria-rich fraction isolated from mesenchymal stromal cells restored oxygen consumption rate and reduced total reactive oxygen species production. Infusion of exogenous mitochondria-rich fraction from mesenchymal stromal cells (mitotherapy) reduced peritoneal bacterial load, improved lung mechanics and histology, and decreased the expression of interleukin-1ß, keratinocyte chemoattractant, indoleamine 2,3-dioxygenase-2, and programmed cell death protein 1 in lung tissue, while increasing keratinocyte growth factor expression and survival rate in cecal ligation and puncture-induced sepsis. Mitotherapy also reduced kidney and liver injury, plasma creatinine levels, and messenger RNA expressions of interleukin-18 in kidney, interleukin-6, indoleamine 2,3-dioxygenase-2, and programmed cell death protein 1 in liver, while increasing nuclear factor erythroid 2-related factor-2 and superoxide dismutase-2 in kidney and interleukin-10 in liver. CONCLUSIONS: Mitotherapy decreased lung, liver, and kidney injury and increased survival rate in cecal ligation and puncture-induced sepsis.

Effects of propofol and its formulation components on macrophages and neutrophils in obese and lean animals.

We hypothesized whether propofol or active propofol component (2,6-diisopropylphenol [DIPPH] and lipid excipient [LIP-EXC]) separately may alter inflammatory mediators expressed by macrophages and neutrophils in lean and obese rats. Male Wistar rats (n = 10) were randomly assigned to receive a standard (lean) or obesity-inducing diet (obese) for 12 weeks. Animals were euthanized, and alveolar macrophages and neutrophils from lean and obese animals were exposed to propofol (50 µM), active propofol component (50 µM, 2,6-DIPPH), and lipid excipient (soybean oil, purified egg phospholipid, and glycerol) for 1 h. The primary outcome was IL-6 expression after propofol and its components exposure by alveolar macrophages extracted from bronchoalveolar lavage fluid. The secondary outcomes were the production of mediators released by macrophages from adipose tissue, and neutrophils from lung and adipose tissues, and neutrophil migration. IL-6 increased after the exposure to both propofol (median [interquartile range] 4.14[1.95-5.20]; p = .04) and its active component (2,6-DIPPH) (4.09[1.67-5.91]; p = .04) in alveolar macrophages from obese animals. However, only 2,6-DIPPH increased IL-10 expression (7.59[6.28-12.95]; p = .001) in adipose tissue-derived macrophages. Additionally, 2,6-DIPPH increased C-X-C chemokine receptor 2 and 4 (CXCR2 and CXCR4, respectively) in lung (10.08[8.23-29.01]; p = .02; 1.55[1.49-3.43]; p = .02) and adipose tissues (8.78[4.15-11.57]; p = .03; 2.86[2.17-3.71]; p = .01), as well as improved lung-derived neutrophil migration (28.00[-3.42 to 45.07]; p = .001). In obesity, the active component of propofol affected both the M1 and M2 markers as well as neutrophils in both alveolar and adipose tissue cells, suggesting that lipid excipient may hinder the effects of active propofol.

Pulmonary morphofunctional effects of mechanical ventilation with high inspiratory air flow.

OBJECTIVE: 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. DESIGN: Prospective, randomized, controlled experimental study. SETTING: University research laboratory. SUBJECTS: Thirty normal male Wistar rats (180-230 g). INTERVENTIONS: 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. MEASUREMENTS AND MAIN RESULTS: 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. CONCLUSIONS: 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.

Eicosapentaenoic Acid Enhances the Effects of Mesenchymal Stromal Cell Therapy in Experimental Allergic Asthma.

Asthma is characterized by chronic lung inflammation and airway hyperresponsiveness. Despite recent advances in the understanding of its pathophysiology, asthma remains a major public health problem and, at present, there are no effective interventions capable of reversing airway remodeling. Mesenchymal stromal cell (MSC)-based therapy mitigates lung inflammation in experimental allergic asthma; however, its ability to reduce airway remodeling is limited. We aimed to investigate whether pre-treatment with eicosapentaenoic acid (EPA) potentiates the therapeutic properties of MSCs in experimental allergic asthma. Seventy-two C57BL/6 mice were used. House dust mite (HDM) extract was intranasally administered to induce severe allergic asthma in mice. Unstimulated or EPA-stimulated MSCs were administered intratracheally 24 h after final HDM challenge. Lung mechanics, histology, protein levels of biomarkers, and cellularity in bronchoalveolar lavage fluid (BALF), thymus, lymph nodes, and bone marrow were analyzed. Furthermore, the effects of EPA on lipid body formation and secretion of resolvin-D1 (RvD1), prostaglandin E2 (PGE2), interleukin (IL)-10, and transforming growth factor (TGF)-ß1 by MSCs were evaluated in vitro. EPA-stimulated MSCs, compared to unstimulated MSCs, yielded greater therapeutic effects by further reducing bronchoconstriction, alveolar collapse, total cell counts (in BALF, bone marrow, and lymph nodes), and collagen fiber content in airways, while increasing IL-10 levels in BALF and M2 macrophage counts in lungs. In conclusion, EPA potentiated MSC-based therapy in experimental allergic asthma, leading to increased secretion of pro-resolution and anti-inflammatory mediators (RvD1, PGE2, IL-10, and TGF-ß), modulation of macrophages toward an anti-inflammatory phenotype, and reduction in the remodeling process. Taken together, these modifications may explain the greater improvement in lung mechanics obtained. This may be a promising novel strategy to potentiate MSCs effects.

Expanded endothelial progenitor cells mitigate lung injury in septic mice.

Endothelial progenitor cells (EPCs) improve survival and reduce organ failure in cecal ligation and puncture-induced sepsis; however, expanded EPCs may represent an even better approach for vascular repair. To date, no study has compared the effects of non-expanded EPCs (EPC-NEXP) with those of expanded EPCs (EPC-EXP) and mesenchymal stromal cells of human (MSC-HUMAN) and mouse (MSC-MICE) origin in experimental sepsis. One day after cecal ligation and puncture sepsis induction, BALB/c mice were randomized to receive saline, EPC-EXP, EPC-NEXP, MSC-HUMAN or MSC-MICE (1 × 10(5)) intravenously. EPC-EXP, EPC-NEXP, MSC-HUMAN, and MSC-MICE displayed differences in phenotypic characterization. On days 1 and 3, cecal ligation and puncture mice showed decreased survival rate, and increased elastance, diffuse alveolar damage, and levels of interleukin (IL)-1ß, IL-6, IL-10, tumor necrosis factor-α, vascular endothelial growth factor, and platelet-derived growth factor in lung tissue. EPC-EXP and MSC-HUMAN had reduced elastance, diffuse alveolar damage, and platelet-derived growth factor compared to no-cell treatment. Tumor necrosis factor-α levels decreased in the EPC-EXP, MSC-HUMAN, and MSC-MICE groups. IL-1ß levels decreased in the EPC-EXP group, while IL-10 decreased in the MSC-MICE. IL-6 levels decreased both in the EPC-EXP and MSC-MICE groups. Vascular endothelial growth factor levels were reduced regardless of therapy. In conclusion, EPC-EXP and MSC-HUMAN yielded better lung function and reduced histologic damage in septic mice.

Intravenous glutamine administration reduces lung and distal organ injury in malnourished rats with sepsis.

Malnutrition is a risk factor for infection, compromising immune response. Glutamine (Gln) protects the lungs and distal organs in well-nourished septic and nonseptic conditions; however, no study to date has analyzed the effects of Gln 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 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-cecal ligation and puncture rats, Gln therapy yielded (a) reduced static lung elastance, alveolar collapse, inflammation (neutrophil infiltration, interleukin 6), and collagen deposition; (b) repair of types I and II epithelial cells; (c) no significant changes in heat shock protein 70 expression or heat shock factor 1 phosphorylation; (d) a greater number of M1 and M2 macrophages in lung tissue; and (e) 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.

Terapia celular nas doenças respiratórias / Cell therapy for respiratory diseases

As células-tronco são definidas como células indiferenciadas, com capacidade de se dividir por período indefinido, em cultura, e se diferenciar em diversos tipos celulares especializados, dependendo do estímulo ao qual são submetidas. Nesse artigo, será realizada uma revisão crítica dos efeitos da terapia com células-tronco em algumas doenças respiratórias tais como: síndrome do desconforto respiratório agudo, fibrose pulmonar, asma e enfisema. Estudos recentes têm mostrado os efeitos benéficos da administração de células-tronco endógenas e exógenas no desenvolvimento, reparo e remodelamento do pulmão em diversas doenças respiratórias. Entretanto, a biologia das células-tronco ainda é pouco entendida devido às limitações técnicas atuais, estando diversas questões ainda sem respostas. Portanto, mais estudos são necessários para ummelhor entendimento dos mecanismos que controlam a divisão e diferenciação dessas células, para que, assim, a terapia celular possa ser utilizada de maneira segura e eficaz em humanos.

Stem cells are defined as undifferentiated progenitors that can self-renew ad infinitum and differentiate into various specialized cell types depending on the stimulus to which they are submitted. In this article, we will perform a critical review of the effects of cell therapy in respiratory diseases such as: acute respiratory distress syndrome, pulmonary fibrosis, asthma,and emphysema. Recent studies have shown the beneficial effects of endogenous and exogenous stem cells in lung development, repair and remodeling in re spiratory diseases. However, the biology of stem cells remains poorly understood due to technical limitations, and some important questions need to be answered. More studies should be performed to better understand the mechanisms that control cell division and differentiation, therefore enabling the use of cell therapy in humanrespiratory diseases.

Stem cells and respiratory diseases

Stem cells have a multitude of clinical implications in the lung. This article is a critical review that includes clinical and experimental studies of MedLine and SciElo database in the last 10 years, where we highlight the effects of stem cell therapy in acute respiratory distress syndrome or more chronic disorders such as lung fibrosis and emphysema. Although, many studies have shown the beneficial effects of stem cells in lung development, repair and remodeling; some important questions need to be answered to better understand the mechanisms that control cell division and differentiation, therefore enabling the use of cell therapy in human respiratory diseases.

As células-tronco têm uma infinidade de implicações clínicas no pulmão. Este artigo é uma revisão crítica que inclui estudos clínicos e experimentais advindos do banco de dados do MEDLINE e SciElo nos últimos 10 anos, onde foram destacados os efeitos da terapia celular na síndrome do desconforto respiratório agudo ou doenças mais crônicas, como fibrose pulmonar e enfisema. Apesar de muitos estudos demonstrarem os efeitos benéficos das células-tronco no desenvolvimento, reparo e remodelamento pulmonar; algumas questões ainda precisam ser respondidas para um melhor entendimento dos mecanismos que controlam a divisão celular e diferenciação, permitindo o uso da terapia celular nas doenças respiratórias.