Pulmonary hypertension is increasingly recognized as an important pathological contributor that influences the mortality, decline in the quality of life, and morbidity of patients who are already affected by underlying life-threatening lung disorders, such as interstitial lung disease and chronic obstructive pulmonary disease. Despite the evident progress that has been made, many scientific and clinical issues remain undetermined and incompletely understood. Furthermore, high altitude geographic settings and hypoxia represent a powerful extreme environment with prominent influence on the pulmonary circulation in both people permanently living at such elevations and those traveling there for different reasons. Many aspects, particularly those linked to genetics and adaptation, are still not known and need further comprehensive research. Finally, since the in utero period of life is crucial path for the later health state, several questions and scientific/clinical issues are still not resolved.

The general philosophy of this special issue is based and created around the following scientific and clinical questions. 1) What do we actually know about pulmonary vascular diseases in the context of other lung diseases and/or hypoxia: diagnosis, pathology, and treatment strategies? 2) Where are we at the moment with regard to the exact knowledge and understanding of the underlying molecular, genetic, and cellular mechanisms? 3) What is the exact histopathological pattern and features of pulmonary vascular remodeling in this subgroup of pulmonary hypertension patients (Clinical Classification 2013, Group 3, and Nice, France).

We would like to invite all investigators in the field to submit their original research works (both basic and clinical studies), as well as review articles. The multidisciplinary approach will be highly desirable. Finally, all unpublished (including those that are not under consideration in other journals) manuscripts will go through a rigorous peer-review process.

Potential topics include but are not limited to the following:

• Molecular and cellular pathobiology and pathophysiology of pulmonary hypertension associated with chronic obstructive pulmonary disease
• Clinical studies with focus on pulmonary vascular disease in the context of chronic obstructive pulmonary disease: diagnosis, molecular signaling and cellular mechanisms, and treatment strategy
• Molecular and cellular pathobiology and pathophysiology of pulmonary hypertension associated with interstitial lung disease
• Clinical studies with focus on pulmonary vascular disease in the context of interstitial lung disease: diagnosis, molecular signaling and cellular mechanisms, and treatment strategy
• High altitude medicine and chronic hypoxia: genetics, evolution, adaptation/acclimatization, and molecular mechanisms of acute and chronic high altitude diseases
• High altitude-induced pulmonary hypertension: experimental and clinical studies
• Cold-induced pulmonary hypertension: experimental and clinical studies
• Developmental lung diseases: experimental and clinical studies
• Other medical conditions: sleep-disordered breathing and alveolar hypoventilation disorders, as well as other lung diseases with mixed restrictive and obstructive pattern