Influence of Macitentan on the Vascular Tone and Recruitment of Finger Capillaries Under Hypobaric Hypoxia in High Altitude

The role of post-translational modifications in driving abnormal cardiovascular complications at high altitude

The high-altitude environment is characterized by hypobaric hypoxia, low temperatures, low humidity, and high radiation, which is a natural challenge for lowland residents entering. Previous studies have confirmed the acute and chronic effects of high altitude on the cardiovascular systems of lowlanders. Abnormal cardiovascular complications, including pulmonary edema, cardiac hypertrophy and pulmonary arterial hypertension were commonly explored. Effective evaluation of cardiovascular adaptive response in high altitude can provide a basis for early warning, prevention, diagnosis, and treatment of altitude diseases. At present, post-translational modifications (PTMs) of proteins are a key step to regulate their biological functions and dynamic interactions with other molecules. This process is regulated by countless enzymes called “writer, reader, and eraser,” and the performance is precisely controlled. Mutations and abnormal expression of these enzymes or their substrates have been implicated in the pathogenesis of cardiovascular diseases associated with high altitude. Although PTMs play an important regulatory role in key processes such as oxidative stress, apoptosis, proliferation, and hypoxia response, little attention has been paid to abnormal cardiovascular response at high altitude. Here, we reviewed the roles of PTMs in driving abnormal cardiovascular complications at high altitude.

Proteomic and Morphological Profiling of Mice Ocular Tissue During High-altitude Acclimatization Process: An Animal Study at Lhasa

Purpose

High-altitude environment mainly with hypobaric hypoxia could induce pathological alterations in ocular tissue. Previous studies have mostly focused on sporadic case reports and simulated high-altitude hypoxia experiments. This aim of this study was to explore the proteomic and morphological changes of ocular tissue in mice at real altitude environment.

Methods

In this study, mice were flown from Chengdu (elevation: 500 m) to Lhasa (elevation: 3600 m). After exposure for 1day, 3, 6, 10, 20, 30, and 40days, the mice were euthanatized to obtain blood and ocular tissue. Serological tests, ocular pathological examinations, integral ocular proteomics analysis, and Western blot were conducted.

Results

We focused on acute phase (1–3 days) and chronic phase (>30 days) during high-altitude acclimatization. Serum interleukin-1 was increased at 3 days, while superoxide dismutase, interleukin-6, and tumor necrosis factor-α showed no statistical changes. H&E staining demonstrated that the cornea was edematous at 3 days and exhibited slower proliferation at 30 days. The choroid showed a consistently significant thickening, while there existed no noticeable changes in retinal thickness. Overall, 4073 proteins were identified, among which 71 and 119 proteins were detected to have significant difference at 3 days and 40 days when compared with the control group. Functional enrichment analysis found the differentiated proteins at 3 days exposure functionally related with response to radiation, dephosphorylation, negative regulation of cell adhesion, and erythrocyte homeostasis. Moreover, the differential profiles of the proteins at 40 days exposure exhibited changes of regulation of complement activation, regulation of protein activation cascade, regulation of humoral immune response, second-messenger-mediated signaling, regulation of leukocyte activation, and cellular iron homeostasis. Interestingly, we found the ocular proteins with lactylation modification were increased along high-altitude adaptation.

Conclusion

This is the first work reporting the ocular proteomic and morphological changes at real high-altitude environment. We expect it would deep the understanding of ocular response during altitude acclimatization.