A Low Concentration of Carbonic Anhydrase Isoenzyme VI in Whole Saliva Is Associated with Caries Prevalence

Abstract

Carbonic anhydrases maintain pH homeostasis in various tissues of the human body by catalyzing the reversible reaction CO₂ + H₂O <=> HCO₃^– + H⁺. Carbonic anhydrase isoenzyme VI (CA VI) is secreted into human saliva by the serous acinar cells of the parotid and submandibular glands. Although it represents about 3% of the total protein in stimulated parotid saliva, its exact physiological significance in the saliva has not been established. In the present study, saliva samples were collected under strictly controlled conditions from young, healthy men and assayed for CA VI concentrations using a specific time–resolved immunofluorometric assay. Salivary secretion rate, pH, buffering capacity, α–amylase activity levels, lactobacillus and Streptococcus mutans counts were also determined, and the results were correlated with the dental status of the subjects. Salivary CA VI concentration, pH and buffering capacity values correlated negatively with the numbers of decayed, missing and filled teeth (DMFT index). The correlations between salivary CA VI concentration and DMFT index were most significant in subjects with poor oral hygiene. No correlation was found between salivary CA VI concentration and lactobacillus or Streptococcus mutans counts. As predicted, salivary lactobacillus and Streptococcus mutans counts showed a close positive correlation with the DMFT index. In contrast, no significant correlation was seen between salivary secretion rate or amylase activity and the DMFT index. The present results indicate that low salivary CA VI concentrations are associated with increased caries prevalence, particularly in subjects with neglected oral hygiene.

Association of polymorphisms in the carbonic anhydrase 6 gene with salivary buffer capacity, dental plaque pH, and caries index in children aged 7–9 years

“…18 Low CAVI concentrations in the saliva were associated with the prevalence of dental caries, especially in individuals with poor oral hygiene. 19 Experimental evidences indicate that CAVI in saliva penetrates plaque and facilitates acid neutralization by salivary bicarbonate. 17 Although CAVI was originally predicted to regulate salivary pH or buffer capacity, 20,21 some studies indicate that these variables are not directly associated with CAVI concentration in saliva.…”

Multiple Binding Modes of Inhibitors to Carbonic Anhydrases: How to Design Specific Drugs Targeting 15 Different Isoforms?

“…45,46 However, nothing is known regarding the involvement of the remaining two acatalytic isoforms, CA X and XI, in human pathologies or what is the physiological function of these two proteins conserved all over the phylogenetic tree in vertebrates. 45 CA IX and XII are well-established anticancer 29 hCA I edema 30 unknown epilepsy 26,31 unknown altitude sickness 32,33 unknown CA III oxidative stress 34−36 unknown CA IV glaucoma 37 hCA I retinitis pigmentosa 38,39 unknown stroke 40 unknown CA VA/VB obesity [20][21][22]41 hCA I, hCA II CA VI cariogenesis 42,43 hCA II CA VII epilepsy 26,31,44 unknown CA VIII neurodegeneration 45 unknown cancer 45 unknown CA IX cancer 24,27,47 hCA I, hCA II CA XII cancer 24,47,48 hCA I, hCA II glaucoma 49 unknown CA XIII sterility 50 unknown CA XIV epilepsy 26,51 unknown retinopathy 52 unknown a No data are available in the literature on CA X and XI involvement in diseases.…”

Purification of Carbonic Anhydrase Isozyme VI (CA-VT) from Swine Saliva.

“…Kivela et al [8] reported no significant correlation between CA-VI concentrations and pH or buffer capacity pH values in saliva. Kivela et al [7] also found no correlation between salivary CA-VI concentration and salivary Lactobacillus or Streptococcus mutans counts. We measured the in vitro antibactericidal activity of swine CA-VI against gram-positive (Staphylococcus aureus) and gramnegative (Escherichia coli) bacteria by minimum inhibitory concentration (MIC) studies on Sabouraud's dextrose agar plate.…”

“…Swine CA-VI did not possess bactericidal activity against these bacteria. Kivela et al [7] described that low salivary CA-VI concentrations are associated with an increased prevalence of caries, particularly in individuals with low standards of oral hygiene. Henkin et al [6] reported that human CA-VI is associated with taste bud growth and development and suggested that inhibition of CA-VI synthesis is associated with the development of taste bud abnormalities and therefore, a loss of taste function.…”