Expectation and expectoration: Information manipulation alters spitting volume, a common proxy for salivary flow

Diagnosis, Prevention, and Treatment of Radiotherapy-Induced Xerostomia: A Review

In patients with head and neck cancer, irradiation (IR)-sensitive salivary gland (SG) tissue is highly prone to damage during radiotherapy (RT). This leads to SG hypofunction and xerostomia. Xerostomia is defined as the subjective complaint of dry mouth, which can cause other symptoms and adversely affect the quality of life. In recent years, diagnostic techniques have constantly improved with the emergence of more reliable and valid questionnaires as well as more accurate equipment for saliva flow rate measurement and imaging methods. Preventive measures such as the antioxidant MitoTEMPO, botulinum toxin (BoNT), and growth factors have been successfully applied in animal experiments, resulting in positive outcomes. Interventions, such as the new delivery methods of pilocarpine, edible saliva substitutes, acupuncture and electrical stimulation, gene transfer, and stem cell transplantation, have shown potential to alleviate or restore xerostomia in patients. The review summarizes the existing and new diagnostic methods for xerostomia, along with current and potential strategies for reducing IR-induced damage to SG function. We also aim to provide guidance on the advantages and disadvantages of the diagnostic methods. Additionally, most prevention and treatment methods remain in the stage of animal experiments, suggesting a need for further clinical research, among which we believe that antioxidants, gene transfer, and stem cell transplantation have broad prospects.

Addition of chocolate milk to diet corresponds to protein concentration changes in human saliva

Salivary proteins have the potential to alter oral sensory perception of foods. In rodents, dietary polyphenol exposure increases salivary concentrations of polyphenol-binding proteins and several cystatins, which correlate with less aversion to polyphenol-rich solutions. If similar salivary shifts occur in humans, then increasing dietary polyphenols may improve orosensory experience of polyphenol-rich foods. We hypothesized that small dietary changes, focused on polyphenols, would increase expression of salivary binding proteins for polyphenols and thus suppress unpleasant polyphenol sensations. However, analogs of salivary polyphenol-binding proteins are found in foods. Thus, we also hypothesized that food-sourced analogs of these salivary proteins would mitigate changes in saliva and sensation. Human subjects (N=55) alternated weeks of consuming a low polyphenol diet and then a regular diet plus a polyphenol-rich chocolate milk (almond, containing no polyphenol-binding proteins, or bovine, containing polyphenol-binding proteins). Statistical analyses revealed both chocolate milk interventions corresponded to changes in relative expression of 96 proteins and calculated concentration of 146 proteins (both after correction for false discovery rate), out of 1,176 proteins identified through proteomics. Of the proteins that changed, proline-rich proteins and cystatins were noticeable, which reflects prior work in animal studies. Subjects rated all chocolate milks as less flavorful after the bovine chocolate milk intervention week compared to low polyphenol weeks, but generally sensory changes were minimal. However, the results confirm that dietary changes coincide with salivary changes, and that some of those changes occur in proteins that have potential to influence oral sensations.

Conditioning of human salivary flow using a visual cue for sour candy

OBJECTIVE

Although the "mouthwatering" to sight, smell, or thought of food is commonly accepted in food and nutrition research, the concept of mouthwatering and human salivary flow conditioning is not well accepted in salivary research. The objective of this study was to revisit whether human salivary flow could be classically conditioned to a previously neutral stimulus.

DESIGN

Sour candy or a non-food control in opaque containers were presented to healthy participants (n = 8). Simple images were consistently paired with container contents. Participants viewed the images for 15 s, then opened the containers and ate (candy) or did not eat (non-food control) the contents. This was repeated 14 times (7 of each stimulus). Order was semi-randomized to ensure one candy and one non-food were presented as the first two and last two stimuli. Saliva was collected with cotton dental rolls during these presentations (first two and last two) after viewing the image for 15 s, but before opening the container.

RESULTS

Participants were successfully conditioned to increase salivary flow in response to the image that predicted candy, as demonstrated by greater weight of saliva in response to 1) the candy-paired image than the non-food-paired image, and 2) the candy-paired image at the end of the first visit compared with the beginning (when the image had no meaning). However, the effect was attenuated during the second visit.

CONCLUSIONS

We demonstrate classical conditioning of human salivary flow is achievable, but the effect may not persist to a second visit.

Is salivary IgA level a potential biomarker for immunosuppression in HIV-positive children? A systematic review and meta-analysis

The aim of this systematic review was to determine whether or not assessment of salivary secretory immunoglobulin A (sIgA) levels could be a potential biomarker for immunosuppression in HIV-positive children. The Patient, Exposure, Comparative, Outcome question was "Is sIgA level a potential biomarker for immunosuppression in HIV-positive children?" Electronic and manual literature searches were conducted in indexed databases (MEDLINE, PubMed, EMBASE, ScienceDirect, and SCOPUS databases) up to and including June 2017. The primary outcome was total mean salivary levels of IgA among HIV seropositive and seronegative children (controls). The weighted mean differences (WMD) of outcomes and 95% confidence intervals (CI) for total mean salivary IgA levels were calculated using a random effect model. Six studies were included. Three studies showed significantly lower salivary IgA levels in HIV-infected children compared with controls. Two studies showed comparable IgA levels in HIV infected and controls. One study showed significantly higher levels of salivary IgA in HIV-infected children as compared to controls. Considering the total mean salivary IgA levels among HIV seropositive and seronegative children, a high degree of heterogeneity (Q value = 254.09, P < .0001, I²  = 98.82%) was noticed among both groups. The overall WMD was not significant (WMD = -1.18, 95% CI, -1.91 to -0.44, P = .39). Whether salivary IgA level is a potential biomarker for immunosuppression in HIV-positive children remains debatable because of limited information available in the current literature. Further, high-quality case-control studies with larger sample size and more solid methodological aspects are required.