17ß-Estradiol Treatment Protects Lungs Against Brain Death Effects in Female Rat Donor.

BACKGROUND: Brain death (BD) affects the viability of lungs for transplantation. A correlation exists between high-lung inflammation after BD and the decrease in female sex hormones, especially estradiol. Therefore, we investigated the effects of 17ß-estradiol (E2) treatment on the lungs of female brain dead rats. METHODS: Female Wistar rats were divided into 4 groups: BD (submitted to BD for 6 h), sham (false operated), E2-T0 (treated with E2 immediately after BD; 50 µg/mL, 2 mL/h), and E2-T3 (treated with E2 after 3 h of BD; 50 µg/mL, 2 mL/h). Lung edema, hemorrhage, and leukocyte infiltration were analyzed. Adhesion molecules were evaluated, and analysis of NO synthase gene and protein expression was performed using real-time PCR and immunohistochemistry, respectively. Release of chemokines and matrix degradation in the lungs was analyzed. RESULTS: BD increased leukocyte infiltration, as shown by intravital microscopy (P = 0.017), bronchoalveolar lavage cell count (P = 0.016), the release of inflammatory mediators (P = 0.02), and expression of adhesion molecules. BD also increased microvascular permeability and the expression and activity of matrix metalloproteinase-9 in the lungs. E2 treatment reduced leukocyte infiltration, especially in the E2-T3 group, release of inflammatory mediators, adhesion molecules, and matrix metalloproteinase activity in the lungs. CONCLUSIONS: E2 treatment was successful in controlling the lung inflammatory response in females submitted to BD. Our results suggest that E2 directly decreases the release of chemokines, restraining cell traffic into the lungs. Thus, E2 has a therapeutic potential, and its role in improving donor lung quality should be explored further.

17ß-Estradiol as a New Therapy to Preserve Microcirculatory Perfusion in Small Bowel Donors.

BACKGROUND: Intestine graft viability compromises retrieval in most brain-dead donors. Small bowel transplantation is a complex procedure with worse outcomes than transplantation of other abdominal organs. The hormone 17ß-estradiol (E2) has shown vascular protective effects in lung tissue of brain death (BD) male rats. Thus, estradiol might be a treatment option to improve the quality of intestinal grafts. METHODS: Male Wistar rats were divided into 3 groups (n = 10/group): rats that were trepanned only (sham-operated), rats subjected to rapid-onset BD, and brain-dead rats treated with E2 (280 µg/kg, intravenous) (BD-E2). Experiments performed for 180 minutes thereafter are included: (a) laser-Doppler flowmetry and intravital microscopy to evaluate mesenteric perfusion; (b) histopathological analysis; (c) real-time polymerase chain reaction of endothelial nitric oxide synthase (eNOS) and endothelin-1; (d) immunohistochemistry of eNOS, endothelin-1, P-selectin, intercellular adhesion molecule 1, and vascular cell adhesion molecule 1 expression; and (e) ELISA for cytokines and chemokines measurement. RESULTS: 17ß-Estradiol improved microcirculatory perfusion and reduced intestinal edema and hemorrhage after BD. The proportions of perfused small vessels were (mean ± scanning electron microscope) BD rats (40% ± 6%), sham-operated rats (75% ± 8%), and BD-E2 rats (67% ± 5%) (P = 0.011). 17ß-Estradiol treatment was associated with 2-fold increase in eNOS protein (P < 0.0001) and gene (P = 0.0009) expression, with no differences in endothelin-1 expression. BD-E2 rats exhibited a reduction in vascular cell adhesion molecule 1 expression and reduced cytokine-induced neutrophil chemoattractant 1 and interleukina-10 serum levels. CONCLUSIONS: 17ß-Estradiol was effective in improving mesenteric perfusion and reducing intestinal edema and hemorrhage associated with BD. The suggestion is that E2 might be considered a therapy to mitigate, at least in part, the deleterious effects of BD in small bowel donors.

Hypertonic saline reduces cell infiltration into the lungs after brain death in rats.

BACKGROUND: Lung transplantation is a treatment method for end stage lung disease, but the availability of donor lungs remains a major constraint. Brain death (BD) induces hemodynamic instability with microcirculatory hypoperfusion and increased inflammation, leading to pulmonary dysfunction. Hypertonic saline solution (HSS) is a volume expander possessing immunomodulatory effects. This study evaluated the influence of HSS on pulmonary dysfunction and inflammation in a rat model of BD. METHODS: BD was induced by inflation of an intracranial balloon catheter. Rats were divided into [1]: Sham, without BD [2]; NS, NaCl treatment (0.9%, 4 mL/kg, i.v.) immediately after BD [3]; HSS1, HSS treatment (NaCl 7.5%, 4 mL/kg, i.v.) immediately after BD; and [4] HSS60, HSS treatment 60 min post BD. All groups were analyzed after 360 min. RESULTS: Animals subjected to BD exhibited increased exhaled O2 and decreased CO2.The number of leukocytes in the lungs was significantly increased in the NS group (p = 0.002) and the HSS treatment was able to reduce it (HSS1, p = 0.018 and HSS60 = 0.030). In parallel, HSS-treated rats showed reduced levels of ICAM-1 expression, which was increased in the NS compared to Sham group. Lung edema was found increased in the NS group animals compared to Sham and no effect of the HSS treatment was observed. There were no differences among the groups in terms of TNF-α, VEGF, and CINC-1 lung concentrations. CONCLUSIONS: HSS is capable of reducing inflammatory cell infiltration into the lung after BD induction, which is associated with the reduction of ICAM-1 expression in organ vessels.

Sex-related differences in lung inflammation after brain death.

BACKGROUND: Donor sex has been suggested to be a factor influencing organ transplantation outcome. Sex hormones possess inflammatory and immune-mediating properties; therefore, immune responses may differ between males and females. Brain death (BD) affects organ function by numerous mechanisms including alterations in hemodynamics, hormonal changes, and increased systemic inflammation. In this study, we investigated sex-dependent differences in the evolution of lung inflammation in a rat model of BD. MATERIALS AND METHODS: BD was induced by a sudden increase in intracranial pressure by rapidly inflating a balloon catheter inserted into the intracranial space. Groups of male, female, and ovariectomized (OVx) female rats were used. Lung vascular permeability, inducible nitric oxide synthase, and intercellular adhesion molecule 1 expression were analyzed 6 h after BD. Serum female sex hormones, vascular endothelial growth factor, and cytokine-induced neutrophil chemoattractant 1 levels were also quantified. Lung sections were analyzed by histology. RESULTS: After 6 h of BD, serum estradiol and progesterone concentrations in female rats were significantly reduced. Lung microvascular permeability was increased in females compared to males. Cytokine-induced neutrophil chemoattractant 1 and vascular endothelial growth factor concentrations were increased in female rats compared to males. Furthermore, female rats showed higher levels of leukocyte infiltration and inducible nitric oxide synthase expression in the lung parenchyma. CONCLUSIONS: Our results indicate that the more severe lung inflammation in female animals after BD might be related to acute estradiol reduction. Based on our findings, we believe that, in a future study, a group of female treated with estradiol after BD could indicate a possible therapy for the control of lung inflammation in the female donor.