Age Differences of Salivary Alpha-Amylase Levels of Basal and Acute Responses to Citric Acid Stimulation Between Chinese Children and Adults

Abstract

It remains unclear how salivary alpha-amylase (sAA) levels respond to mechanical stimuli in different age groups. In addition, the role played by the sAA gene (AMY1) copy number and protein expression (glycosylated and non-glycosylated) in sAA activity has also been rarely reported. In this study, we analyzed saliva samples collected before and after citric acid stimulation from 47 child and 47 adult Chinese subjects. We observed that adults had higher sAA activity and sAA glycosylated levels (glycosylated sAA amount/total sAA amount) in basal and stimulated saliva when compared with children, while no differences were found in total or glycosylated sAA amount between them. Interestingly, adults showed attenuated sAA activity levels increase over those of children after stimulation. Correlation analysis showed that total sAA amount, glycosylated sAA amount, and AMY1 copy number × total sAA amount were all positively correlated with sAA activity before and after stimulation in both groups. Interestingly, correlation r between sAA levels (glycosylated sAA amount and total sAA amount) and sAA activity decreased after stimulation in children, while adults showed an increase in correlation r. In addition, the correlation r between AMY1 copy number × total sAA amount and sAA activity was higher than that between AMY1 copy number, total sAA amount, and sAA activity, respectively. Taken together, our results suggest that total sAA amount, glycosylated sAA amount, and the positive interaction between AMY1 copy number and total sAA amount are crucial in influencing sAA activity before and after stimulation in children and adults.

Changes Occurring on the Activity of Salivary Alpha-Amylase Proteoforms in Two Naturalistic Situations Using a Spectrophotometric Assay

“…This is in line with the fact that in the case of sAA, the quantity of the enzyme does not correspond with its activity, as was previously indicated in another report [21]. Additionally, GsAA activity and concentration have been specifically described as showing a low correlation [30]. Further studies should be undertaken to clarify the divergence, but other factors could also be related, such as the different affinities of the substrates used for sAA activity measurement of the different proteoforms [9].…”

Salivary alpha‐amylase activity and concentration in horses with acute abdominal disease: Association with outcome

“…This difference in associations between the activity and concentration has also been observed in paraoxonase‐1 (PON1) in human serum . A possible explanation for these differences between sAA activity and concentration could be due to the fact that there are specific isoforms of sAA that may differ in their enzymatic activities, as is found in humans . Overall, the results of this study suggest that sAA activity is preferred to concentration as a means of evaluating the prognosis of horses with acute abdominal disease.…”

Saliva matters: Reviewing the role of saliva in the rheology and tribology of liquid and semisolid foods. Relation to in-mouth perception

“…Most instrumental studies use stimulated saliva, probably because these conditions produce a larger amount of saliva. Unstimulated and stimulated saliva have been shown to differ in their concentration of proteins and mucin and their buffering capacity, and some differences have also been found for α-amylase amount and activity (Yang et al, 2015). For these reasons, a single saliva donor does not represent the average of the naturally-occurring differences between healthy individuals and over the day, and neither does pooled saliva from a small number of subjects (Muñoz-González, Brulé, Feron, & Canon, 2019); this point could raise experimental concerns and lead to limitations.…”