Pathological characteristics of vasculopathies in pulmonary hypertension
| Definition according to Dana point criteria | Presence in Fra-2 tg mice | Changes characteristic for human SSc-PAH 6 7 | Changes characteristic for human IPAH 6 7 | |
|---|---|---|---|---|
| Concentric laminar intimal thickening | Expansion of (myo-) fibroblasts, SMCs | +++ (figure 1E) | +++ | (+) |
| Concentric and eccentric non-laminar thickening | Predominantly composed of fibroblasts/connective tissue | + (figure 1F,G) | + | + |
| Adventitial thickening | ++ (figure 1F) | ++ | ++ | |
| Medial hypertrophy | Increase due to hypertrophy/-plasia of SMCs, to an increase in connective tissue and elastic fibres, extension of SMCs into non-muscularised arteries | + (figure 1H) | + | + |
| Plexiform lesion | Focal proliferation of endothelial channels lined by myofibroblasts, SMCs and connective tissue matrix | − | (+) | +++ |
| Dilation lesion | Thin-walled vein-like vessel distally to a plexiform lesion | − | − | + |
| Arteritis | Rarely primary, often associated with plexiform/dilation lesions, arterial wall may be necrotic and/or be infiltrated with chronic and acute inflammatory cells | − | − | + |
| Perivascular inflammatory infiltrates | ++ (figure 1H) | ++ | + | |
| Interstitial changes | Fibrosis, inflammatory infiltrates | +++ (Supplementary figure 1B–D) | +++ | (+) |
| Pulmonary occlusive venopathy | Extensive and diffuse occlusion of pulmonary venules and veins, occluding fibrous tissue may be loose and edematous with variable cellularity or dense, sclerotic and accellular; intimal thickening mainly involves venules and small veins, luminal occlusion can be solid or eccentric with multiple lumina; media may become thickened with an increase in elastic fibres and SMCs | − | ++ | (+) |
| Pulmonary microvasculopathy | Localised capillary proliferation that invades pulmonary interstitium, vessels and, less commonly, airways; panlobular and patchy distribution, often associated with pulmonary hemosiderosis | − | − | − |
−absent.
(+)hardly ever present/not characteristic.
+rarely/can be observed.
++often/common feature.
+++very often/characteristic feature.
Fra-2, fos-related antigen 2; IPAH, idiopathic pulmonary arterial hypertension; PAH, pulmonary arterial hypertension; SMC, smooth muscle cells; SSc, systemic sclerosis; tg, transgenic.