Perivascular inflammatory cells and their association with pulmonary arterial remodelling in dogs with pulmonary hypertension due to myxomatous mitral valve disease

Pulmonary Hypertension Secondary to Myxomatous Mitral Valve Disease in Dogs: Current Insights into the Histological Manifestation and Its Determining Factors

“…An increase in external diameter due to MMVD is observed both in PVH conditions secondary to the disease and even in the period preceding PH [43]. However, fully masculinized vessels represent an increasingly high percentage in dogs with PVH [43]. Patients with MMVD and coexisting PVH also showed a higher ratio of medial layer thickness to total vessel diameter compared to patients with MMVD without PVH [37,[44][45][46].…”

“…In one study, the perivascular number of B lymphocytes, T lymphocytes, and macrophages was significantly increased in the MMVD + PVH group compared to the MMVD without PVH and control group. The accumulation of these cells was observed even before the onset of remodeling in larger vessels, while small arterioles were already undergoing masculinization processes [43]. Inflammatory cell infiltration in PVH can be stimulated by many factors.…”

“…The current suggestion is that inflammatory cells are involved in increasing pulmonary vascular diameter [43,65]. In one study, the perivascular number of B lymphocytes, T lymphocytes, and macrophages was significantly increased in the MMVD + PVH group compared to the MMVD without PVH and control group.…”

“…Among them, by far the greatest changes are in the muscular layer of the vasculature, which is known as the thickening of the medial [37]. An increase in external diameter due to MMVD is observed both in PVH conditions secondary to the disease and even in the period preceding PH [43]. However, fully masculinized vessels represent an increasingly high percentage in dogs with PVH [43].…”

“…The difference between PVH and PAH in terms of the degree of endothelial proliferation is puzzling. In the case of PVH, the presence of excessive endothelial proliferation was excluded, which is typical in PAH [37,43].…”