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Updated: Mar 9, 2026

Investigating Aortic Valve Calcification via Isolation and Culture of T Lymphocytes using Feeder Cells from Irradiated Buffy Coat
Published on: February 4, 2021
Infectious seeds of valve calcification: Exploring the bacterial hypothesis in the pathogenesis of calcific aortic
Antonella Forlino1,2, Paola Giordani3, Cristina Merla4
1Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Pavia, Italy.
Background:
Calcific aortic valve disease (CAVD) is a multifactorial condition characterized by progressive leaflet calcification with a potential role for bacterial colonization in its pathogenesis. This study investigates clinical, microbiological and molecular features of calcified versus non-calcified aortic regurgitation (AR) valves.
Methods:
This is a prospective, observational study, whose primary objective was to compare the occurrence of bacterial detection between CAVD and AR. The secondary objectives included the evaluation of bone-related calcification markers in valves from CAVD and AR patients.
Results:
We analysed 31 CAVD and 8 AR valves, yielding 111 leaflets (84 calcified, 27 non-calcified). Light microscopy of CAVD leaflets revealed near-complete disruption of the three-layered valve architecture, with calcified masses extending through the leaflets, sparse cellularity and focal micro-angiogenesis; no bacteria were detected by GRAM, PAS or TEM. Enrichment culture detected low-virulence bacteria in 5.95% of CAVD and 4.16% of AR leaflets; 16S rRNA PCR was positive in 22.5% of CAVD and 12.5% of AR cases, with Staphylococcus and Streptococcus spp. predominating. Calcium content was significantly higher in CAVD leaflets (p = .001) and correlated with dyslipidemia (p = .02). Osterix expression was higher in valves with positive microbiological findings (p < .0001), while ALP was increased in CAVD and bicuspid valves regardless of microbial status. Valve interstitial cells from CAVD exhibited spontaneous in vitro calcification, unlike controls.
Conclusion:
The early osteogenic marker osterix was found to be upregulated in patients whose valves tested positive for microbial DNA, suggesting a potential role for bacteria in driving cellular differentiation towards an osteoblastic phenotype in CAVD.
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