HSP-70-Mediated Hyperbaric Oxygen Reduces Brain and Pulmonary Edema and Cognitive Deficits in Rats in a Simulated High-Altitude Exposure.

High-mountain sickness is characterized by brain and pulmonary edema and cognitive deficits. The definition can be fulfilled by a rat model of high-altitude exposure (HAE) used in the present study. This study aimed to investigate the protective effect of hyperbaric oxygen therapy (HBO2T) and to determine the underlying mechanisms. Rats were subjected to an HAE (9.7% O2 at 0.47 absolute atmosphere of 6,000 m for 3 days). Immediately after termination of HAE, rats were treated with HBO2T (100% O2 at 2.0 absolute atmosphere for 1 hour per day for 5 consecutive days) or non-HBO2T (21% O2 at 1.0 absolute atmosphere for 1 hour per day for 5 consecutive days). As compared to non-HAE+non-HBO2T controls, the HAE+non-HBO2T rats exhibited brain edema and resulted in cognitive deficits, reduced food and water consumption, body weight loss, increased cerebral inflammation and oxidative stress, and pulmonary edema. HBO2T increased expression of both hippocampus and lung heat shock protein (HSP-70) and also reversed the HAE-induced brain and pulmonary edema, cognitive deficits, reduced food and water consumption, body weight loss, and brain inflammation and oxidative stress. Decreasing the overexpression of HSP-70 in both hippocampus and lung tissues with HSP-70 antibodies significantly attenuated the beneficial effects exerted by HBO2T in HAE rats. Our data provide in vivo evidence that HBO2T works on a remodeling of brain/lung to exert a protective effect against simulated high-mountain sickness via enhancing HSP-70 expression in HAE rats.

Dimethylarginine dimethylaminohydrolase II overexpression attenuates LPS-mediated lung leak in acute lung injury.

Acute lung injury (ALI) is a severe hypoxemic respiratory insufficiency associated with lung leak, diffuse alveolar damage, inflammation, and loss of lung function. Decreased dimethylaminohydrolase (DDAH) activity and increases in asymmetric dimethylarginine (ADMA), together with exaggerated oxidative/nitrative stress, contributes to the development of ALI in mice exposed to LPS. Whether restoring DDAH function and suppressing ADMA levels can effectively ameliorate vascular hyperpermeability and lung injury in ALI is unknown, and was the focus of this study. In human lung microvascular endothelial cells, DDAH II overexpression prevented the LPS-dependent increase in ADMA, superoxide, peroxynitrite, and protein nitration. DDAH II also attenuated the endothelial barrier disruption associated with LPS exposure. Similarly, in vivo, we demonstrated that the targeted overexpression of DDAH II in the pulmonary vasculature significantly inhibited the accumulation of ADMA and the subsequent increase in oxidative/nitrative stress in the lungs of mice exposed to LPS. In addition, augmenting pulmonary DDAH II activity before LPS exposure reduced lung vascular leak and lung injury and restored lung function when DDAH activity was increased after injury. Together, these data suggest that enhancing DDAH II activity may prove a useful adjuvant therapy to treat patients with ALI.

Andrographolide protects against LPS-induced acute lung injury by inactivation of NF-κB.

BACKGROUND: Nuclear factor-κB (NF-κB) is a central transcriptional factor and a pleiotropic regulator of many genes involved in acute lung injury. Andrographolide is found in the plant of Andrographis paniculata and widely used in Traditional Chinese Medicine, exhibiting potently anti-inflammatory property by inhibiting NF-κB activity. The purpose of our investigation was designed to reveal the effect of andrographolide on various aspects of LPS induced inflammation in vivo and in vitro. METHODS AND RESULTS: In vivo, BALB/C mice were subjected to LPS injection with or without andrographolide treatments to induce ALI model. In vitro, MLE-12 cells were stimulated with LPS in the presence and absence of andrographolide. In vivo, pulmonary inflammation, pulmonary edema, ultrastructure changes of type II alveolar epithelial cells, MPO activity, total cells, neutrophils, macrophages, TNF-α, IL-6 and IL-1ß in BALF, along with the expression of VCAM-1 and VEGF were dose-dependently attenuated by andrographolide. Meanwhile, in vitro, the expression of VCAM-1 and VEGF was also reduced by andrographolide. Moreover, our data showed that andrographolide significantly inhibited the ratios of phospho-IKKß/total IKKß, phospho-IκBα/total IκBα and phospho-NF-κB p65/total NF-κB p65, and NF-κB p65 DNA binding activities, both in vivo and in vitro. CONCLUSIONS: These results indicate that andrographolide dose-dependently suppressed the severity of LPS-induced ALI, more likely by virtue of andrographolide-mediated NF-κB inhibition at the level of IKKß activation. These results suggest andrographolide may be considered as an effective and safe drug for the potential treatment of ALI.

Sodium tanshinone iia sulfonate attenuates seawater aspiration-induced acute pulmonary edema by up-regulating Na(+),K(+)-ATPase activity.

Relieving pulmonary edema is the key of a successful treatment to seawater drowning. Sodium tanshinone IIA sulfonate (STS) has been observed to reduce lung edema from lipopolysaccharide (LPS)-induced lung injury. In this study the authors investigated whether STS attenuates seawater aspiration-induced acute pulmonary edema, and examined the effects of sodium-potassium adensosine triphosphatase (Na(+),K(+)-ATPase) on it. Seawater was instilled through an endotracheal tube. The anesthetized and spontaneously breathing rats received STS intraperitoneally after seawater aspiration. Pao(2), lung wet-to-dry weight ratio, and pulmonary microvascular permeability were tested. The authors explored the effects of STS on the expression and activity of Na(+),K(+)-ATPase in vivo and in vitro. Additionally, the authors investigated the role of the extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway in the stimulation of Na(+),K(+)-ATPase by STS. The results showed that STS significantly improved hypoxemia, attenuated lung edema, and alleviated seawater-induced lung injury in vivo. Both in vivo and in vitro, it was observed that STS up-regulated the expression and activity of Na(+),K(+)-ATPase. ERK1/2 inhibitor partially blocked the effects of STS on Na(+),K(+)-ATPase activity in alveolar type II cells following seawater incubation. These results indicated that STS could improve seawater aspiration-induced acute pulmonary edema by up-regulating Na(+),K(+)-ATPase activity, and the ERK1/2 signaling pathway may be involved in it.

EGLN1 involvement in high-altitude adaptation revealed through genetic analysis of extreme constitution types defined in Ayurveda.

It is being realized that identification of subgroups within normal controls corresponding to contrasting disease susceptibility is likely to lead to more effective predictive marker discovery. We have previously used the Ayurvedic concept of Prakriti, which relates to phenotypic differences in normal individuals, including response to external environment as well as susceptibility to diseases, to explore molecular differences between three contrasting Prakriti types: Vata, Pitta, and Kapha. EGLN1 was one among 251 differentially expressed genes between the Prakriti types. In the present study, we report a link between high-altitude adaptation and common variations rs479200 (C/T) and rs480902 (T/C) in the EGLN1 gene. Furthermore, the TT genotype of rs479200, which was more frequent in Kapha types and correlated with higher expression of EGLN1, was associated with patients suffering from high-altitude pulmonary edema, whereas it was present at a significantly lower frequency in Pitta and nearly absent in natives of high altitude. Analysis of Human Genome Diversity Panel-Centre d'Etude du Polymorphisme Humain (HGDP-CEPH) and Indian Genome Variation Consortium panels showed that disparate genetic lineages at high altitudes share the same ancestral allele (T) of rs480902 that is overrepresented in Pitta and positively correlated with altitude globally (P < 0.001), including in India. Thus, EGLN1 polymorphisms are associated with high-altitude adaptation, and a genotype rare in highlanders but overrepresented in a subgroup of normal lowlanders discernable by Ayurveda may confer increased risk for high-altitude pulmonary edema.

Novel role for CFTR in fluid absorption from the distal airspaces of the lung.

The active absorption of fluid from the airspaces of the lung is important for the resolution of clinical pulmonary edema. Although ENaC channels provide a major route for Na(+) absorption, the route of Cl(-) transport has been unclear. We applied a series of complementary approaches to define the role of Cl(-) transport in fluid clearance in the distal airspaces of the intact mouse lung, using wild-type and cystic fibrosis Delta F508 mice. Initial studies in wild-type mice showed marked inhibition of fluid clearance by Cl(-) channel inhibitors and Cl(-) ion substitution, providing evidence for a transcellular route for Cl(-) transport. In response to cAMP stimulation by isoproterenol, clearance was inhibited by the CFTR inhibitor glibenclamide in both wild-type mice and the normal human lung. Although isoproterenol markedly increased fluid absorption in wild-type mice, there was no effect in Delta F508 mice. Radioisotopic clearance studies done at 23 degrees C (to block active fluid absorption) showed approximately 20% clearance of (22)Na in 30 min both without and with isoproterenol. However, the clearance of (36)Cl was increased by 47% by isoproterenol in wild-type mice but was not changed in Delta F508 mice, providing independent evidence for involvement of CFTR in cAMP-stimulated Cl(-) transport. Further, CFTR played a major role in fluid clearance in a mouse model of acute volume-overload pulmonary edema. After infusion of saline (40% body weight), the lung wet-to-dry weight ratio increased by 28% in wild-type versus 64% in Delta F508 mice. These results provide direct evidence for a functionally important role for CFTR in the distal airspaces of the lung.