Lung disease at high altitude

A Case of Acute Respiratory Distress Syndrome Following Non-thoracic Trauma in a Patient With Idiopathic Pulmonary Fibrosis

A 72-year-old man with idiopathic pulmonary fibrosis (IPF) was on home oxygen therapy at 1 L/min. He fell approximately 3 m onto a concrete surface while painting the roof of his home and was emergently transported to a local hospital due to pain in his lower back and right lower limb. His initial Krebs von den Lungen level decreased with medical treatments but has shown an increasing trend over the past three respiratory outpatient visits. His other medical conditions, including dyslipidemia, lumbar pain, and allergic rhinitis, were treated with several drugs prescribed by a nearby clinic. At the previous hospital, an increased oxygen demand of around 5 L via mask was noted, although other vital signs were stable. A plain whole-body computed tomography (CT) scan revealed pulmonary edema, a fracture of the right femoral neck, and a fracture of the third lumbar vertebral body. During transfer to our hospital for surgery, crossing the Amagi Pass at an elevation of approximately 830 m, the patient's respiratory condition rapidly deteriorated. Upon arrival, the cardiac wall movement was hyperdynamic, and PaO2 was 29 mmHg under supplemental oxygen at 15 L/min, necessitating oral endotracheal intubation and initiation of mechanical ventilation. A chest CT scan showed worsening diffuse ground-glass opacities in both lungs compared to the previous CT scan at the referring hospital. Despite positive pressure ventilation with the mechanical ventilator, the patient's condition did not improve, and he died in the emergency room. Acute respiratory distress syndrome (ARDS) can occur following severe trauma but the onset of ARDS due to moderate trauma is extremely rare. Considering the possibility of an acute exacerbation of IPF prior to the injury, this report discusses the possibility of developing ARDS due to trauma-induced cytokines and lung damage from damage-associated molecular patterns, the possibility of inhaling dust while working on the roof, pneumonia caused by prescribed medication, viral infections, exposure to pollen and/or high altitude while passing through the mountain pass, and hypoxemia-inducing pulmonary edema.

Vitamin D3 improved hypoxia-induced lung injury by inhibiting the complement and coagulation cascade and autophagy pathway

BACKGROUND

Pulmonary metabolic dysfunction can cause lung tissue injury. There is still no ideal drug to protect against hypoxia-induced lung injury, therefore, the development of new drugs to prevent and treat hypoxia-induced lung injury is urgently needed. We aimed to explore the ameliorative effects and molecular mechanisms of vitamin D3 (VD3) on hypoxia-induced lung tissue injury.

METHODS

Sprague-Dawley (SD) rats were randomly divided into three groups: normoxia, hypoxia, and hypoxia + VD3. The rat model of hypoxia was established by placing the rats in a hypobaric chamber. The degree of lung injury was determined using hematoxylin and eosin (H&E) staining, lung water content, and lung permeability index. Transcriptome data were subjected to differential gene expression and pathway analyses. In vitro, type II alveolar epithelial cells were co-cultured with hepatocytes and then exposed to hypoxic conditions for 24 h. For VD3 treatment, the cells were treated with low and high concentrations of VD3.

RESULTS

Transcriptome and KEGG analyses revealed that VD3 affects the complement and coagulation cascade pathways in hypoxia-induced rats, and the genes enriched in this pathway were Fgb/Fga/LOC100910418. Hypoxia can cause increases in lung edema, inflammation, and lung permeability disruption, which are attenuated by VD3 treatment. VD3 weakened the complement and coagulation cascade in the lung and liver of hypoxia-induced rats, characterized by lower expression of fibrinogen alpha chain (Fga), fibrinogen beta chain (Fgb), protease-activated receptor 1 (PAR1), protease-activated receptor 3 (PAR3), protease-activated receptor 4 (PAR4), complement (C) 3, C3a, and C5. In addition, VD3 improved hypoxic-induced type II alveolar epithelial cell damage and inflammation by inhibiting the complement and coagulation cascades. Furthermore, VD3 inhibited hypoxia-induced autophagy in vivo and in vitro, which was abolished by the mitophagy inducer, carbonyl cyanide-m-chlorophenylhydrazone (CCCP).

CONCLUSION

VD3 alleviated hypoxia-induced pulmonary edema by inhibiting the complement and coagulation cascades and autophagy pathways.

Positive association between moderate altitude and chronic lower respiratory disease mortality in United States counties

For patients with chronic lower respiratory disease, hypobaric hypoxia at a high altitude is considered a risk factor for mortality. However, the effects of residing at moderately high altitudes remain unclear. We investigated the association between moderate altitude and chronic lower respiratory disease mortality. In particular, we examined the lower 48 United States counties for age-adjusted chronic lower respiratory disease mortality rates, altitude, and socioeconomic factors, including tobacco use, per capita income, population density, sex ratio, unemployment, poverty, and education between 1979 and 1998. The socioeconomic factors were incorporated into the correlation analysis as potential covariates. Considerable positive (R = 0.235; P <0.001) and partial (R = 0.260; P <0.001) correlations were observed between altitude and chronic lower respiratory disease mortality rate. In the subgroup with high COPD prevalence subgroup, even stronger positive (R = 0.346; P <0.001) and partial (R = 0.423, P <0.001) correlations were observed. Multivariate regression analysis of all available socioeconomic factors revealed that additional knowledge on altitude improved the adjusted R2 values from 0.128 to 0.186 for all counties and from 0.301 to 0.421 for counties with high COPD prevalence. We concluded that in the lower 48 United States counties, even a moderate altitude may pose considerable risks in patients with chronic lower respiratory disease.

Exploration of ethno-medicinal knowledge among rural communities of Pearl Valley; Rawalakot, District Poonch Azad Jammu and Kashmir

BACKGROUND

Medicinal plants are the basic source of health care in the Pearl Valley District Poonch, Azad Jammu, and Kashmir. The basic aim of present study was to record information about the use of plants in herbal preparation and quantification of recorded data.

MATERIALS AND METHODS

The research was conducted with the null hypothesis that there was no differential distribution of knowledge among the communities between genders and among different age groups in the study area and across cultural medicinal uses of the plants are similar. To check these hypotheses information about medicinal plants was collected from 46 laypeople and 18 herbalists by using an open ended and semistructured questionnaire. Different ethnobotanical indices were calculated in order to quantify the knowledge on the medicinal plants reported in the study.

RESULTS

Our study recorded 136 species of medicinal plants belonging to 45 families with Asteraceae (14 species) as the dominant family of the area. Decoction (26 species), juice and powder (24 species each) were most common methods of preparation. Spearman's correlation analysis showed that age and gender had the significant effect on both numbers of mentioned species and different uses. A number of known medicinal plants and the number of different uses (H: 38.51; p < 0.001) differ significantly as indicated by Kruskal-Wallis tests. These results showed that the knowledge about the plant varies among different age groups, which were the first hypothesis of the present study. The highest use values (UVs) were reported for Berberis lyceum and Ajuga bracteosa (1.13 each) followed by Abies pindrow (1.03). Highest informant consensus factor (ICF) values were recorded for digestive system diseases (ICF = 0.90) and muscular and skeletal system diseases (ICF = 0.89). The value of Jaccarad index ranged from 6.11 to 32.97 with an average value of 19.84, percentage of similarity was highest between study area and Pir Lasura National Park (34.62%).

CONCLUSION

High similarity might be due to the fact that the communities living in these areas have same sociocultural values and have more opportunities to exchange their traditional knowledge. The present study provides practical evidence about the use of medicinal plants among the inhabitants of the Pearl Valley.

Descriptive study of plant resources in the context of the ethnomedicinal relevance of indigenous flora: A case study from Toli Peer National Park, Azad Jammu and Kashmir, Pakistan

BACKGROUND

This paper presents the first quantitative ethnobotanical study of the flora in Toli Peer National Park of Azad Jammu and Kashmir, Pakistan. Being a remote area, there is a strong dependence by local people on ethnobotanical practices. Thus, we attempted to record the folk uses of the native plants of the area with a view to acknowledging and documenting the ethnobotanical knowledge. The aims of the study were to compile an inventory of the medicinal plants in the study area and to record the methods by which herbal drugs were prepared and administered.

MATERIALS AND METHODS

Information on the therapeutic properties of medicinal plants was collected from 64 local inhabitants and herbalists using open ended and semi-structured questionnaires over the period Aug 2013-Jul 2014. The data were recorded into a synoptic table comprising an ethnobotanical inventory of plants, the parts used, therapeutic indications and modes of application or administration. Different ethnobotanical indices i.e. relative frequencies of citation (RFC), relative importance (RI), use value (UV) and informant consensus factor (Fic), were calculated for each of the recorded medicinal plants. In addition, a correlation analysis was performed using SPSS ver. 16 to check the level of association between use value and relative frequency of citation.

RESULTS

A total of 121 species of medicinal plants belonging to 57 families and 98 genera were recorded. The study area was dominated by herbaceous species (48%) with leaves (41%) as the most exploited plant part. The Lamiaceae and Rosaceae (9% each) were the dominant families in the study area. Among different methods of preparation, the most frequently used method was decoction (26 species) of different plant parts followed by use as juice and powder (24 species each), paste (22 species), chewing (16 species), extract (11 species), infusion (10 species) and poultice (8 species). The maximum Informant consensus factor (Fic) value was for gastro-intestinal, parasitic and hepatobiliary complaints (0.90). Berberis lycium Ajuga bracteosa, Prunella vulgaris, Adiantum capillus-veneris, Desmodium polycarpum, Pinus roxburgii, Albizia lebbeck, Cedrella serrata, Rosa brunonii, Punica granatum, Jasminum mesnyi and Zanthoxylum armatum were the most valuable plants with the highest UV, RFC and relative importance values. The Pearson correlation coefficient between UV and RFC (0.881) reflects a significant positive correlation between the use value and relative frequency of citation. The coefficient of determination indicated that 77% of the variability in UV could be explained in terms of RFC.

CONCLUSION

Systematic documentation of the medicinal plants in the Toli Peer National Park shows that the area is rich in plants with ethnomedicinal value and that the inhabitants of the area have significant knowledge about the use of such plants with herbal drugs commonly used to cure infirmities. The results of this study indicate that carrying out subsequent pharmacological and phytochemical investigations in this part of Pakistan could lead to new drug discoveries.

Human immunodeficiency virus-1 transgene expression increases pulmonary vascular resistance and exacerbates hypoxia-induced pulmonary hypertension development

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by increased pulmonary arterial resistance and vessel remodeling. Patients living with human immunodeficiency virus-1 (HIV-1) have an increased susceptibility to develop severe pulmonary hypertension (PH) irrespective of their CD4+ lymphocyte counts. While the underlying cause of HIV-PAH remains unknown, the interaction of HIV-1 proteins with the vascular endothelium may play a critical role in HIV-PAH development. Hypoxia promotes PH in experimental models and in humans, but the impact of HIV-1 proteins on hypoxia-induced pulmonary vascular dysfunction and PAH has not been examined. Therefore, we hypothesize that the presence of HIV-1 proteins and hypoxia synergistically augment the development of pulmonary vascular dysfunction and PH. We examined the effect of HIV-1 proteins on pulmonary vascular resistance by measuring pressure-volume relationships in isolated lungs from wild-type (WT) and HIV-1 Transgenic (Tg) rats. WT and HIV-1 Tg rats were exposed to 10% O₂ for four weeks to induce experimental pulmonary hypertension to assess whether HIV-1 protein expression would impact the development of hypoxia-induced PH. Our results demonstrate that HIV-1 protein expression significantly increased pulmonary vascular resistance (PVR). HIV-1 Tg mice demonstrated exaggerated pulmonary vascular responses to hypoxia as evidenced by greater increases in right ventricular systolic pressures, right ventricular hypertrophy and vessel muscularization when compared to wild-type controls. This enhanced PH was associated with enhanced expression of HIF-1α and PCNA. In addition, in vitro studies reveal that medium from HIV-infected monocyte derived macrophages (MDM) potentiates hypoxia-induced pulmonary artery endothelial proliferation. These results indicate that the presence of HIV-1 proteins likely impact pulmonary vascular resistance and exacerbate hypoxia-induced PH.

Effect of sustained high altitude on asthma patients

Due to factors such as allergen avoidance and the decrease of air pollution, sustained stays in a high-altitude climate have been recommended for asthma patients for a long time. There are also documented effects and favorable influence on the health of permanent residents at high altitude; for example, the frequency of allergic sensitization to house dust mite in asymptomatic subjects is much lower than at sea level. In the context of this article, 'high altitude' means 1500-2500 m above sea level. The aim of the review is to summarize the available data on the effects of a sustained stay of asthmatic patient data between 1500-1800 m above sea level in alpine altitudes (Europe). Climatic conditions in South America or in Africa are completely different from the altitudes discussed in this review. We conclude that the available evidence suggests a significant benefit of high altitude for asthmatic patients, particularly in steroid-dependent patients.

Sudden death due to asphyxia by esophageal polyp: two case reports and review of asphyxial deaths

Asphyxia, not an uncommon cause of sudden death, may result from numerous etiologies. Foreign-body aspiration and strangulation are 2 extrinsic causes. Airway obstruction may also be caused by laryngeal edema, asthma, infection, or anaphylaxis. Chronic causes of asphyxia include musculoskeletal diseases (eg, muscular dystrophy, amyotrophic lateral sclerosis), neurologic disorders (eg, myasthenia gravis, multiple sclerosis), respiratory disease (eg, emphysema, chronic bronchitis), or tumors. The manner of death in cases of asphyxiation may be natural, accidental, homicide, or suicide. For the death investigator, determining the cause and manner of death can often be quite challenging. We report here 2 cases of an esophageal fibrovascular polyp causing sudden asphyxial death, review of the literature, and discussion of other differential diagnoses in the case of asphyxial death.

Midkine is regulated by hypoxia and causes pulmonary vascular remodeling

Midkine (MK) is expressed in a precise temporal-spatial pattern during lung morphogenesis; however, its role in pulmonary homeostasis is unknown. Increased MK staining and mRNA expression were observed in the lungs of hypoxia-susceptible CAST/eiJ mice during hypoxia. MK expression was induced by hypoxia in cell lines in vitro. Because the transcription factor hypoxiainducible factor-1alpha (HIF-1alpha) modulates cellular responses to hypoxia, we tested whether increased expression of MK in the lung was mediated by HIF-1alpha. HIF-1alpha enhanced the transcription of MK, acting on HIF-1alpha regulatory elements located in the MK gene promoter. Site-directed mutagenesis of the 3' HIF response element in the MK promoter blocked the stimulatory effects of HIF-1alpha. To directly assess the role of MK on lung morphogenesis, transgenic mice were generated in which MK was expressed in the respiratory epithelial cells of the developing lung. MK increased muscularization of small pulmonary arteries, increasing alpha-smooth muscle actin and caldesmon staining and the expression of myocardin. MK directly enhanced the expression of myocardin and the smooth muscle-specific genes alpha-smooth muscle actin, calponin, and SM-22 in vascular smooth muscle precursor cells. Expression of MK in the respiratory epithelium is regulated by hypoxia and HIF-1alpha. These data provide a model wherein the respiratory epithelium responds to hypoxia via HIF-1alpha-dependent regulation of MK, enhancing myocardin expression to influence pulmonary vascular gene expression.

The influence of altitude in bronchial asthma

BACKGROUND

Some asthmatic children living in mountain areas experience significant improvement in daily symptoms and in the degree of bronchial obstruction. The aim of this study is to investigate the effect of altitude on the prevalence and morbidity of childhood bronchial asthma.

METHODS

A questionnaire regarding the history and symptoms of asthma was distributed to 874 children aged 6-12 years, to be completed by their parents with the help of their pediatrician. A total of 583 children lived at sea level, 180 at an altitude between 501 and 800 meters, and 111 at an altitude between 801 and 1,200 meters. All children with recurrent cough, shortness of breath, wheezing, and a history of bronchial asthma were considered to have bronchial asthma.

RESULTS

The prevalence of childhood bronchial asthma in the mountains (800-1,200 meters) was twice as low as that at sea level (15.8% of children) (p <0.01). Parental smoking was more frequent in children who lived at sea level than in the mountains. Additionally, consumption of fish and oranges was more frequent at sea level. Children with asthma who lived in the mountains were absent fewer days from school per year (0.2) and had fewer nights with dyspnea per year (0.5) than asthmatic children who lived at sea level (1.6 days and 25 nights, respectively).

CONCLUSIONS

Bronchial asthma in children who live at high altitudes is characterized by low prevalence and low morbidity.

Chronic hypoxia decreases K(V) channel expression and function in pulmonary artery myocytes

Activity of voltage-gated K+ (KV) channels regulates membrane potential (E(m)) and cytosolic free Ca2+ concentration ([Ca2+](cyt)). A rise in ([Ca2+](cyt))in pulmonary artery (PA) smooth muscle cells (SMCs) triggers pulmonary vasoconstriction and stimulates PASMC proliferation. Chronic hypoxia (PO(2) 30-35 mmHg for 60-72 h) decreased mRNA expression of KV channel alpha-subunits (Kv1.1, Kv1.5, Kv2.1, Kv4.3, and Kv9.3) in PASMCs but not in mesenteric artery (MA) SMCs. Consistently, chronic hypoxia attenuated protein expression of Kv1.1, Kv1.5, and Kv2.1; reduced KV current [I(KV)]; caused E(m) depolarization; and increased ([Ca2+](cyt)) in PASMCs but negligibly affected KV channel expression, increased I(KV), and induced hyperpolarization in MASMCs. These results demonstrate that chronic hypoxia selectively downregulates KV channel expression, reduces I(KV), and induces E(m) depolarization in PASMCs. The subsequent rise in ([Ca2+](cyt)) plays a critical role in the development of pulmonary vasoconstriction and medial hypertrophy. The divergent effects of hypoxia on KV channel alpha-subunit mRNA expression in PASMCs and MASMCs may result from different mechanisms involved in the regulation of KV channel gene expression.