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Nailfold Videocapillaroscopic 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)
doi: 10.18176/jiaci.0524

Background: Hereditary angioedema with C1-inhibitor deficiency (C1-INH-HAE) and acquired angioedema related to 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, but no data are available on the possible structural alterations of the vessels.
Objective: This study aims at evaluating the features of the nailfold capillaries to highlight possible structural anomalies in patients affected by C1-INH-HAE in comparison with the healthy population and ACEI-AAE patients in comparison with hypertensive controls.
Methods: With nailfold videocapillaroscopy (NVC), we assessed: apical, internal, and external diameter, loop length, intercapillary distance, 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: C1-INH-HAE patients (n = 34) had significant structural alterations of the capillaries compared to healthy controls (n = 28): 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/year. In ACEI-AAE patients, NVC showed no alterations versus hypertensive controls. NVCs performed in two C1-INH-HAE patients during attacks showed no changes compared to the remission phase.
Conclusions: C1-INH-HAE patients have important structural capillary alterations, confirming the involvement of microcirculation in the pathogenesis of angioedema.

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