Detection of nanobacteria-like material from calcified cardiac valves with rheumatic heart disease.

Background: Nanobacterium contributes to pathological calcification in human renal stones and psammoma bodies in ovarian cancer. Pathological calcification is also present in cardiac valves with rheumatic heart disease. The aim of this study was to detect, isolate, culture, and characterize nanobacteria-like material from human calcified cardiac valves with rheumatic heart disease.

Methods: Normal and calcified cardiac valve groups, as well as positive (nanobacteria strain Se90) and negative (serum radiated with 30 kGy of γ-ray) control groups, were included in this study. Part of each valve was immunostained with nanobacterial antibody 8D10, and the remaining parts were homogenized, filtered, and maintained in culture. The cultures were checked with a microscope weekly. Culture medium at different time points was analyzed with a spectrophotometer. The cultures maintained for 3 weeks were further examined with immunofluorescence double staining and transmission electron microscopy.

Results: While 26 of 29 calcified valves stained positive for 8D10 antibody, all normal valves stained negative. Mobile tiny particles were observed under a microscope in the calcified valve group and the Se90 group. Optical densities were significantly different among groups (P<.001). Immunofluorescence double staining displayed tiny green fluorescence particles in the calcified valve group, in the Se90 group, and in two samples of the normal valve group. Transmission electron microscopy analysis indicated that cultured particles from calcified valves ranging in size from 88 to 341 nm had an obvious cell membrane structure similar to that of Se90.

Conclusions: The nanobacteria-like material has been isolated and cultured from calcified cardiac valves with rheumatic heart disease, and its characteristics are similar to those of Se90.