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P ulmonary arterial hypertension (PAH) is a rapidly progressive disease characterized by obstructive remodeling of distal pulmonary arteries (<500 μm), leading to a progressive elevation in pulmonary vascular resistance and subsequent right heart failure and death. There is currently no cure for PAH, which has a very poor prognosis (mean survival of 2.8 years).1 It is well known that pulmonary arteries display complex structural and functional changes in PAH and that pulmonary endothelial cell (EC) dysfunction plays a crucial role in the disease progression. Despite an increased knowledge in the past years about PAH pathobiological cellular and molecular mechanisms, we still do not know what initiates this disease and its characteristic pulmonary vascular remodeling. Editorial see p 1545 Clinical Perspective on p 1597Pericytes are central regulators of vascular development, stabilization, maturation, and remodeling, modulating EC Background-Pericytes and their crosstalk with endothelial cells are critical for the development of a functional microvasculature and vascular remodeling. It is also known that pulmonary endothelial dysfunction is intertwined with the initiation and progression of pulmonary arterial hypertension (PAH). We hypothesized that pulmonary endothelial dysfunction, characterized by abnormal fibroblast growth factor-2 and interleukin-6 signaling, leads to abnormal microvascular pericyte coverage causing pulmonary arterial medial thickening. Methods and Results-In human lung tissues, numbers of pericytes are substantially increased (up to 2-fold) in distal PAH pulmonary arteries compared with controls. Interestingly, human pulmonary pericytes exhibit, in vitro, an accentuated proliferative and migratory response to conditioned media from human idiopathic PAH endothelial cells compared with conditioned media from control cells. Importantly, by using an anti-fibroblast growth factor-2 neutralizing antibody, we attenuated these proliferative and migratory responses, whereas by using an anti-interleukin-6 neutralizing antibody, we decreased the migratory response without affecting the proliferative response. Furthermore, in our murine retinal angiogenesis model, both fibroblast growth factor-2 and interleukin-6 administration increased pericyte coverage. Finally, using idiopathic PAH human and NG2DsRedBAC mouse lung tissues, we demonstrated that this increased pericyte coverage contributes to pulmonary vascular remodeling as a source of smooth muscle-like cells. Furthermore, we found that transforming growth factor-β, in contrast to fibroblast growth factor-2 and interleukin-6, promotes human pulmonary pericyte differentiation into contractile smooth muscle-like cells. Conclusions-To the best of our knowledge, this is the first report of excessive pericyte coverage in distal pulmonary arteries in human PAH. We also show that this phenomenon is directly linked with pulmonary endothelial dysfunction. 10 In particular, pericytes that are found along arterioles and capillaries express different degrees...

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Although the causal pathomechanisms contributing to remodelling of the pulmonary vascular bed in pulmonary arterial hypertension (PAH) are still unclear, several analogous features with carcinogenesis have led to the emergence of the cancer-like concept. The major similarities concern the altered crosstalk between cells from different tissue types, unexplained proliferation and survival of pulmonary smooth muscle and endothelial cells, the metabolic (glycolytic) shifts, and the association with the immune system. However, major differences between PAH and cancer exist, including the absence of invasion and metastasis, as well as the pathogenic genes involved and the degrees of angiogenesis impairment and genetic instability. It is clear that PAH is not a cancer, but this cancer-like concept has opened a new field of investigation and raises the possibility that antiproliferative and/or oncological drugs may exert therapeutic effects not only in cancer, but also in PAH. Such analogies and differences are discussed here. @ERSpublications Intriguing analogies between PAH pathogenesis and carcinogenesis are observed, but crucial differences also exist

Objective. Pulmonary venoocclusive disease (PVOD) is an uncommon form of pulmonary hypertension (PH) characterized by obstruction of small pulmonary veins. Pulmonary venous involvement has been reported in pathologic assessment of patients with systemic sclerosis (SSc) presenting with precapillary PH. High-resolution computed tomography (HRCT) of the chest is a noninvasive diagnostic tool used to screen for PVOD. No HRCT data are available on SSc patients with precapillary PH. We undertook this study to evaluate the frequency and effect on prognosis of HRCT signs of PVOD in SSc patients with precapillary PH.Methods. We reviewed chest HRCT data from 26 SSc patients with precapillary PH and 28 SSc patients without pulmonary arterial hypertension (PAH) or interstitial lung disease (ILD).Results. The radiographic triad of HRCT signs of PVOD (lymph node enlargement [57.7% versus 3.6%], centrilobular ground-glass opacities [46.2% versus 10.7%], and septal lines [88.5% versus 7.1%]) was significantly more frequent in SSc patients with precapillary PH than in SSc patients without PAH or ILD (all P < 0.005). Indeed, 61.5% of SSc patients with precapillary PH had >2 of these signs. Cardiomegaly (P < 0.0001), pulmonary artery enlargement (P < 0.0001), and pericardial effusion (P < 0.0005) were also significantly more frequent in SSc patients with precapillary PH. Pulmonary venous involvement was histologically confirmed in 2 patients with radiographic signs of PVOD. The presence of >2 radiographic signs of PVOD was associated with the occurrence of pulmonary edema after initiation of PAH-specific therapy (in 8 of 16 patients) and with more rapid progression from diagnosis of PH to death.Conclusion. HRCT signs of PVOD are frequently observed in SSc patients with precapillary PH, correlated with histologic assessment, and were associated with a high risk of pulmonary edema.Pulmonary arterial hypertension (PAH) is a severe and progressive disease, characterized by elevated pulmonary artery pressure leading to right-sided heart failure and death (1,2). A definite diagnosis of PAH requires right-sided heart catheterization (RHC) showing a mean pulmonary artery pressure (PAP) of Ն25 Drs.

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BackgroundViral respiratory infections are the main causes of asthma exacerbation. The susceptibility of asthmatics to develop an exacerbation when they present with severe pneumonia due to SARS-CoV-2 infection is unknown. The objective of this study was to investigate the characteristics and outcomes of asthmatic patients with COVID-19 pneumonia who required hospitalisation during the spring 2020 outbreak in Paris, France.MethodsA prospective cohort follow-up was carried out from March 15 to April 15, 2020 in Bicêtre Hospital, University Paris-Saclay, France. All hospitalised patients with a SARS-CoV-2 infection who reported a history of asthma were included.ResultsAmong 768 hospitalised patients, 37 (4.8%) reported a history of asthma, which had been previously confirmed by a pulmonologist in 85% of cases. Patients were mainly female (70%), non-smokers (85%), with a median age of 54 years (interquartile range, IQR 42–67). None of them presented with an asthma exacerbation. Twenty-two (59%) had major comorbidities and 31 (84%) had a body mass index ≥25 kg·m−2. The most common comorbidities were obesity (36%), hypertension (27%) and diabetes (19%). All patients had a confirmed diagnosis of COVID-19 pneumonia on computed tomography of the chest. Eosinopenia was a typical biologic feature with a median count of 0/mm3 (IQR 0–0). Eleven patients (30%) were admitted in intensive care unit with three death (8.1%) occurring in the context of comorbidities.ConclusionAsthmatics were not overrepresented among patients with severe pneumonia due to SARS-CoV-2 infection who required hospitalisation. Worst outcomes were observed mainly in patients with major comorbidities.