Comprehensive organic profiling of biological particles derived from blood

Physical attributes of salivary calcium particles and their interaction with gingival epithelium

Background

The formation of dental plaque and its involvement in the pathogenesis of periodontitis is a topic of intense interest given the high prevalence of periodontitis in humans. Even though calcium-based particles play an active role in both dental plaque formation and periodontitis, few publications describe the physical-chemical properties of these particles.

Methods

Saliva samples were collected from healthy volunteers. From these samples, saliva-derived particles were isolated and stained for calcium using calcein or Fluo-4. The salivary particles were also subjected to characterization by flow cytometry and immunoblotting. Internalization of calcein-labeled salivary particles by gingival epithelial cells was visualized by confocal microscopy.

Results

We found that calcium-based salivary particles from healthy volunteers varied greatly in size but were enriched in particles of sizes at or greater than 1.5 μm. Immunoblotting analysis of the salivary particles identified several proteins including albumin, fetuin-A, and statherin, which have been found in calcium phosphate particles from other tissues or are known to modulate calcium homeostasis in saliva. In addition, calcium particles were internalized by both gingival epithelial cells and monocyte-derived macrophages.

Conclusion

Salivary calcium particles were enriched in the micrometer range, internalized by gingival epithelial cells, and contain albumin, fetuin-A and statherin, regulators of particle formation. These characteristics of the calcium-based salivary particles and their biological activities provide a basis for further studies to understand the molecular basis for pathogenesis of periodontitis.

Calciprotein Particles: Balancing Mineral Homeostasis and Vascular Pathology

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Ectopic calcification and formation of mineralo-organic particles in arteries of diabetic subjects

Vascular calcification occurs in various diseases including atherosclerosis, chronic kidney disease and type 2 diabetes but the mechanism underlying mineral deposition remains incompletely understood. Here we examined lower limb arteries of type 2 diabetes subjects for the presence of ectopic calcification and mineral particles using histology, electron microscopy and spectroscopy analyses. While arteries of healthy controls showed no calcification following von Kossa staining, arteries from 83% of diabetic individuals examined (19/23) revealed microscopic mineral deposits, mainly within the tunica media. Mineralo-organic particles containing calcium phosphate and proteins such as albumin, fetuin-A and apolipoprotein-A1 were detected in calcified arteries. Ectopic calcification and mineralo-organic particles were observed in a majority of diabetic patients and predominantly in arteries showing hyperplasia. While a low number of subjects was examined and information about disease severity and patient characteristics is lacking, these calcifications and mineralo-organic particles may represent signs of tissue dysfunction.

Calcium Carbonate Nanoparticles Can Activate the Epithelial⁻Mesenchymal Transition in an Experimental Gastric Cancer Model

Previously, we have shown the possibility of intramucosal gastric carcinoma induction by the intragastric administration of a mixture of formaldehyde and hydrogen peroxide in rats. In this study, we report a sizable increase in carcinogenic properties of the mixture when a suspension containing calcium carbonate nanoparticles was added to it. This technique allowed us to reduce both the number of the carcinogen administrations from twelve to two and the time to the cancer induction from six to four months. Although the induced tumors were represented by the intramucosal carcinomas, they were characterized by the extensive invasion of individual tumor cells and their clusters into the muscle layer and serosa as well as into the omentum and blood vessels. Considering that the invasive tumor cells were positive for vimentin, Snail and TGF-β2, we concluded that their invasion was the result of the activation of epithelial–mesenchymal transition (EMT) mechanisms. Thus, taking into account the data obtained, it can be assumed that under the conditions of inflammation or carcinogenesis, the calcium carbonate nanoparticles may affect the activation of EMT mechanisms.