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Nailfold Videocapillaroscopy Findings in Bradykinin-Mediated Angioedema

Cesoni Marcelli A1, Loffredo S1,2, Petraroli A1, Carucci L1, Mormile I1, Ferrara AL1, Spadaro G1, Genovese A1, Bova M1

1Department of Translational Medical Sciences and Center for Basic and Clinical Immunology Research (CISI), University of Naples Federico II, Naples, Italy
2Institute of Experimental Endocrinology and Oncology “G. Salvatore”, National Research Council, Naples, Italy

J Investig Allergol Clin Immunol 2021; Vol 31(5) : 404-416
doi: 10.18176/jiaci.0524

Background: Hereditary angioedema with C1-inhibitor deficiency (C1-INH-HAE) and acquired angioedema related to angiotensin-converting enzyme (ACE) inhibitors (ACEI-AAE) are types of bradykinin-mediated angioedema without wheals characterized by recurrent swelling episodes. Recent evidence suggests that a state of “vascular preconditioning” predisposes individuals to attacks, although no data are available on possible structural alterations of the vessels.
Objective: This study aims to compare the features of nailfold capillaries to highlight possible structural anomalies between patients affected by C1-INH-HAE and controls and between patients with ACEI-AAE and hypertensive controls.
Methods: We used nailfold videocapillaroscopy (NVC) to assess the following: apical, internal, and external diameter; loop length; intercapillary distance; and capillary density, distribution, and morphology. Plasma levels of vascular endothelial growth factor (VEGF) A, VEGF-C, angiopoietin (Ang) 1, and Ang2 were also measured. Results: Compared with healthy controls (n=28), C1-INH-HAE patients (n = 34) were characterized by significant structural alterations of the capillaries, such as greater intercapillary distance (216 vs 190 μm), increased apical, internal, and external diameter (28 vs 22 μm; 22 vs 20 μm; and 81 vs 65 μm, respectively), decreased density (4 vs 5 capillaries/mm2), more irregular capillary distribution, and more tortuous morphology. Apical diameter was enlarged in patients with ≥12 attacks per year. In ACEI-AAE patients, NVC showed no alterations with respect to hypertensive controls. NVC performed in 2 C1-INH-HAE patients during attacks showed no changes compared with the remission phase.
Conclusions: We detected major structural capillary alterations in C1-INH-HAE patients, thus confirming the involvement of microcirculation in the pathogenesis of angioedema.

Key words: C1-inhibitor, Hereditary angioedema, ACE-inhibitor angioedema, Vascular preconditioning, Capillaries