Salivary metals, age, and gender correlate with cultivable oral Candida carriage levels

Abstract

Background: Little is known about the normal range of metal levels in unstimulated saliva, nor whether these might impact Candida carriage in healthy individuals. Both are important in determining which populations are at risk for candidiasis, as the availability of metal ions can influence the growth and pathogenesis of Candida albicans. Objective: We quantified salivary metals of healthy individuals to determine the correlation with C. albicans oral colonization. Design: Unstimulated whole saliva was collected from healthy adults and plated to determine fungal carriage, and metal content was measured using ICP-mass spectrometry (ICP-MS). Results: Zinc was most abundant, followed by iron, copper, manganese, and nickel. Cultivable oral Candida carriage was found in 48% of people. Total protein levels did not differ in salivas from donors with or without carriage. However, innate fungicidal activity was increased in donors with carriage; correlations between levels of several metals were stronger in salivas with fungal carriage, indicating a shift in the oral environment. Concentrations of copper and manganese, as well as age and gender, were significantly predictive of carriage levels in a multiple regression model. Conclusions: Salivary copper and manganese content along with age and gender could be used as a predictive metric for individuals that are more susceptible to Candida overgrowth.

Risk factors for the presence of dental black plaque

“…1 ). Unstimulated whole saliva samples were collected as described elsewhere 17 . Each participant provided a sample of drinking water (for those drinking tap water) or specified the brand of mineral water consumed.…”

Candida albicans Ras1 Inactivation Increases Resistance to Phagosomal Killing by Human Neutrophils

“…C andida albicans is an opportunistic fungus colonizing the oral cavity in over half of healthy individuals (1); however, when the immune system is compromised, this normally commensal organism may become pathogenic and cause oropharyngeal candidiasis (OPC). Recruitment of phagocytic cells is considered a crucial early response to mucosal invasion by C. albicans.…”

Iron Chelator Deferasirox Reduces Candida albicans Invasion of Oral Epithelial Cells and Infection Levels in Murine Oropharyngeal Candidiasis

“…Salivary iron estimation. Salivary iron levels were estimated using inductively coupled plasma resonance mass spectroscopy (ICP-MS), as described previously (16). Murine saliva was thawed, and 0.050 ml from each mouse was pipetted into an acid-cleaned polypropylene digestion tube.…”

“…However, acid produced by oral bacteria can decrease the pH of the saliva (15), thereby increasing iron availability. Iron is the second most abundant metal in saliva (16), and it has been proposed that 30% of total salivary iron is soluble (17). Also, unlike human intestinal cells, which express a divalent metal transporter (reviewed in reference 18), there are no known mechanisms for iron absorption for oral mucosa.…”

“…Very little is known about the effect of metals on C. albicans growth in the oral cavity, although oral carriage of yeast has been shown to correlate with salivary metal levels (16). Given the importance of iron in C. albicans virulence, deferasirox treatment may help alleviate OPC or may be indicated for preventive/prophylactic treatment of high-risk immunosuppressed populations.…”