Association between self-replicating calcifying nanoparticles and aortic stenosis: a possible link to valve calcification

Aims: Among various hypotheses proposed for pathological tissue calcification,recent evidence supports the possibility that self-replicatingcalcifying nanoparticles (CNPs) can contribute to such calcification.These CNPs have been detected and isolated from calcified humantissues, including blood vessels and kidney stones, and arereferred to as nanobacteria. We evaluated calcific aortic valvesfor the presence of CNP. Methods and results: Calcific aortic valves were obtained from 75 patients undergoingsurgical valve replacement. The control group was formed byeight aortic valves corresponding to patients with heart transplants.In the microbiology laboratory, valves were screened for CNPusing a 4–6 weeks specific culture method. The culturefor CNP was positive in 48 of the 75 valves with aortic stenosis(64.0%) in comparison with zero of eight (0%) for the controlgroup (P = 0.0005). The observation of cultures by way of scanningelectron microscopy highlighted the resemblance in size andmorphology of CNP. Conclusion: Self-replicating calcific nanometer-scale particles, similarto those described as CNP from other calcific human tissues,can be cultured and visualized from calcific human aortic valves.This finding raises the question as to whether CNP contributeto the pathogenesis of the disease or whether they are onlyinnocent bystanders.