Attenuated acute salivary α-amylase responses to gustatory stimulation with citric acid in thin children

Decreased salivary α-amylase activity responding to citric acid stimulation in Myasthenia gravis with malnutrition

Objectives

Malnutrition, defined according to Nutritional risk screening (NRS 2002), is commonly observed in patients of Myasthenia gravis (MG), a neuromuscular disorder manifested by varied degrees of skeletal muscle weakness. Because biochemical composition of saliva changes in correspondence to alterations in nutritional status, we tested our hypothesis that a certain saliva component(s) might serve as a biomarker(s) for nutrition status of MG, particularly for those MG patients with high risk of malnutrition.

Materials and methods

60 MG patients and 60 subjects belonging to the healthy control group (HCG) were enrolled in this case-control study. The salivary α-amylase (sAA) activity, salivary flow rate (SFR), pH, total protein density (TPD), and the concentrations of chloride and calcium ions in MG group with or without malnutrition were measured before and after citric acid stimulation. Thereafter, the relationship between sAA activity and BMI was determined in MG and HCG.

Results

Compared with HCG, more patients with malnutrition, increased TPD and chloride and calcium concentrations but decreased pH value and SFR both before and after acid stimulation, as well as reduced sAA activity, pH and TPD responses to acid stimulation. MG with malnutrition showed decreased sAA activity and TPD responding to acid stimulation compared with those without malnutrition. Compared with normal BMI, sAA activity response to acid stimulation was reduced in low BMI. There was a significant strong positive correlation between the ratio of sAA activity and BMI in MG.

Conclusions

Salivary biochemical characteristics are abnormally altered in MG with malnutrition. Altered sAA activity responding to acid stimulation was associated with malnutrition.

Clinical relevance

Decreased sAA activity responding to acid stimulation can reflect malnutrition state and may be one potential screening marker for MG patients with high risk of malnutrition.

Diurnal pattern of salivary alpha-amylase and cortisol under citric acid stimulation in young adults

Background

Saliva composition has diurnal variations. Citric acid stimulation plays a major role in the change of salivary flow rate and salivary composition. However, diurnal variations and sex differences in salivary alpha-amylase (sAA), pH, salivary flow rate (SFR), and salivary cortisol before and after citric acid stimulation remain unclear.

Methods

We recruited 30 healthy volunteers, including 15 women (24.7 ± 1.0 years old) and 15 men (25.3 ± 1.3 years old). At four time points (T1, 7:00; T2, 10:00; T3, 16:00; and T4, 20:00), saliva was collected from healthy volunteers before and after citric acid stimulation; and sAA, pH, SFR and salivary cortisol were measured and compared between men and women.

Results

There were circadian fluctuations in sAA activity, SFR, pH, and cortisol level both before and after citric acid stimulation, and the diurnal fluctuations of these indexes were not affected by citric acid stimulation. There were significant differences in salivary cortisol between men and women before and after acid stimulation in T1. Neither SFR nor pH showed sex-related differences before or after acid stimulation. The variation trend of sAA activity was contrary to that of cortisol, with a significant negative correlation.

Conclusions

Our data suggest that sAA and cortisol showed diurnal fluctuation, and the variation characteristics of male and female under resting state and acid stimulation were basically the same. The variation trend of salivary alpha-amylase activity was opposite to that of cortisol, with significant negative correlation. Our findings may enable the selection of the correct sampling time for research and the selection of appropriate sampling strategies in studies investigating chronic psychosocial conditions.

Decreased basal and stimulated salivary parameters by histopathological lesions and secretory dysfunction of parotid and submandibular glands in rats with type 2 diabetes

Patients with type 2 diabetes mellitus (T2DM) present with dry mouth, polydipsia and taste impairment due to salivary secretion disorder. However, the underlying functional mechanism of T2DM remains unknown. The present study found that T2DM rats had significantly lower salivary flow rate and salivary alpha amylase activity, and attenuated salivary secretion responses to acid stimulation compared with control rats. Histopathological observation found that T2DM rats had inflammatory cell infiltration with increased expressions of IL-6 and TNF-α, oxidative stress, including decreased total superoxide dismutase activity and increased malondialdehyde content, and decreased expressions of β1 adrenergic receptor, cholinergic receptor, aquaporin-5 and protein kinase A in salivary glands, in particular the parotid gland. These results indicated that parotid gland impairment was more severe compared with submandibular gland impairment. Reduced salivary secretion may be associated with histopathological lesions and decreased regulation in secretory pathways in salivary glands.

Abnormalities in acute salivary biochemical characteristic responses to gustatory stimulation with citric acid in chronic non-atrophic gastritis

BACKGROUND AND AIM

Salivary characteristics are altered in gastrointestinal diseases and related to oral taste disorder. However, specific salivary biochemical characteristics and their relationships with oral taste disturbances in chronic non-atrophy gastritis (CNAG) remain uncertain.

METHODS

Seventy patients with CNAG and 70 subjects in healthy control group (HCG) were enrolled in our study. The levels of salivary flow rate (SFR), pH, salivary α-amylase (sAA) activity, total protein density (TPD), chloride concentration, and calcium concentration were determined before and after citric acid stimulation and compared between CNAG with and without oral taste disturbances.

RESULTS

Average body mass index (BMI) of CNAG (17.75 ± 2.08) was lower than that of HCG (21.96 ± 1.72, P < 0.01). Compared with HCG, CNAG showed increased TPD and calcium concentration but decreased SFR both before and after acid stimulation (P < 0.01), as well as reduced sAA and salivary chloride responses to acid stimulation (P < 0.01). Compared with CNAG with normal BMI (24.29%, 17/70), sAA activity response to acid stimulation was reduced in those with low BMI (75.71%, 53/70, P < 0.05). Under resting condition, CNAG with dry mouth (55.71%, 39/70) showed increased SFR and decreased TPD (P < 0.05), as compared with CNAG without dry mouth (44.29%, 31/70). Compared with CNAG without bitter taste (57.14%, 40/70), pH was decreased in those with bitter taste (42.86%, 30/70) under both resting and stimulated conditions (P < 0.05).

CONCLUSION

Decreased sAA activity may reflect malnutrition state and be one potential marker of poor digestion, decreased salivary pH may contribute to bitter taste perception, and reduced TPD might be a cause of dry mouth in CNAG.

A cluster analysis of the relationship between sucking habits, consistency of food ingested, and taste sensitivity in children

As sucking habits and eating behavior may be interrelated and also associated with taste, body composition, and sociodemographic factors, the objective was to perform an exploratory analysis to identify groups of children with a high degree of association between intragroup subjects, providing explanation and interpretation of the data. The study initially included 352 prepubertal children (197 girls; 7- to 11-year-old), from whom information about sociodemographic characteristics, duration of breastfeeding, past bottle-feeding and non-nutritive sucking habits, taste sensitivity, body mass index (BMI), and consistency of food ingested were collected. Salivary concentrations of amylase and total protein were also determined. Data were submitted to cluster analysis (hierarchical analysis, K-means, and silhouette plot), one-way ANOVA and correlation tests. Cluster analysis included 159 children, generating three reliable and meaningful clusters: Cluster 1 (labeled "good tasters"), was characterized by older children and higher taste sensitivity; Cluster 2 ("softer food consistency") by longer bottle-feeding duration and children who eat food with lower consistency, and Cluster 3 ("breastfed") by longer breastfeeding duration (silhouette coefficient = 0.61). Cluster 3 also showed the higher percentage of normal-weight children, normal delivery, maternal schooling, and lower rate of past non-nutritional sucking habit. No correlation was found between salivary amylase and total protein concentrations, taste sensitivity and BMI, although taste sensitivity showed to be higher among girls (p = 0.002; power = 88%). The study identified three clusters, highlighting the relationship between nutritional sucking habits, consistency of food ingested, and sociodemographic characteristics. Most importantly, a close relation between bottle-feeding and consumption of soft food consistency was observed.

Increased salivary fluid flow in children with newly diagnosed allergic rhinitis

OBJECTIVES

The pathogenesis of allergic rhinitis (AR) may involve dysregulation of the autonomic nervous system (ANS). Salivary fluid flow and salivary alpha-amylase (sAA) secretion are able to reflect the activity of parasympathetic (PNS) and sympathetic nervous system (SNS), respectively. The study aims to address the ANS profile in children with newly diagnosed AR by measuring the salivary secretion pattern.

METHODS

We recruited thirty-three children with newly diagnosed AR and thirty-one age- and sex-matched healthy children as control. Saliva samples were collected in the morning and the salivary parameters, including salivary flow rate (SFR, ml/min) and sAA secretion rate (μg/min), were determined accordingly. We also measured the gene copy number of the sAA gene, AMY1, for each individual.

RESULTS

We detected a significantly higher SFR in AR children compared with healthy control (2.20 ± 0.55 vs. 1.63 ± 0.61; p = 0.0002). Similar sAA secretion rate was observed between the two groups (312.8 ± 124.8 (Healthy) vs. 347.9 ± 114.0 (AR) μg/min; p = 0.2444). Besides, the two groups did not differ in AMY1 gene copy number (7.2 ± 2.3 (Healthy) vs. 7.7 ± 2.2 (AR); p = 0.3493).

CONCLUSIONS

Our results implicate an overactivity of the PNS while normal SNS activity in children with newly diagnosed AR. The findings support a contributing role of the ANS dysfunction in the pathogenesis of AR.

Human amylase gene copy number variation as a determinant of metabolic state

INTRODUCTION

Humans have multiple genes encoding amylase that are broadly divided into salivary (AMY1) and pancreatic (AMY2) genes. They exhibit some of the greatest copy numbers of any human gene, an expansion possibly driven by increased dietary starch intake. Within the population, amylase gene copy number is highly variable and there is evidence of an inverse association between AMY1 copy number and BMI.

AREAS COVERED

We examine the evidence for the link between AMY1 and BMI, its potential mechanisms, and the metabolic effects of salivary and pancreatic amylase, both in the gastrointestinal tract and the blood

EXPERT COMMENTARY

Salivary amylase may influence postprandial 'cephalic phase' insulin release, which improves glucose tolerance, while serum amylase may have insulin-sensitizing properties. This could explain the favorable metabolic status associated with higher AMY1 copy number. The association with BMI is harder to explain and is potentially mediated by increased flux of undigested starch into the ileum, with resultant effects on short-chain fatty acids (SCFAs), changes in gut microbiota and effects on appetite and energy expenditure in those with low copy number. Future research on the role of amylase as a determinant of metabolic health and BMI may lead to novel therapies to target obesity.

Altered Salivary Alpha-Amylase Secretion in Patients with Ulcerative Colitis

Purpose

Patients with ulcerative colitis (UC) frequently present with psychological disturbances as well as dysfunctions of autonomic nervous system (ANS). Salivary alpha-amylase (sAA) secretion is predominantly controlled by sympathetic nervous activity, while salivary fluid secretion is by parasympathetic nervous activity. Thus, it is speculated that alterations of salivary secretion may be addressed in UC populations.

Methods

Thirty-five UC patients as well as 32 age- and sex-matched healthy controls were enrolled. Saliva samples before and after citric acid stimulation were collected from each participant, and salivary flow rate (SFR) was calculated accordingly. Western blotting and quantitative PCR were applied to measure the sAA level and sAA gene (AMY1) copy number, respectively. The psychological disorders, anxiety and depression, were evaluated by the scoring system of Hospital Anxiety and Depression Scale (HADS) for each participant.

Results

We observed robustly increased prevalence of anxiety (p < 0.001) as well as depression (p < 0.001) in UC patients relative to controls. Interestingly, we detected elevated basal (p = 0.015) and stimulated (p = 0.021) sAA levels in the UC populations compared to controls. However, no differences were found for basal (p = 0.643) or stimulated (p = 0.402) SFR between the two study groups. Besides, AMY1 gene copy number was comparable between UC patients and controls.

Conclusions

Our results reveal an overactivity of the sympathetic nervous system and a normal activity of the parasympathetic nervous system in the UC population.

Salivary Diagnostics in Pediatrics: Applicability, Translatability, and Limitations

In the last decade, technological advances, combined with an improved appreciation of the ability of saliva to inform caregivers about both oral health and systemic disease, have led to the emergence of salivary diagnostic platforms. However, the majority of these assays have targeted diseases that more commonly affect the adult population, largely neglecting infants and children who arguably could benefit the most from non-invasive assessment tools for health monitoring. Gaining access into development, infection, and disease through comprehensive "omic" analyses of saliva could significantly improve care and enhance health access. In this review, we will highlight novel applications of salivary diagnostics in pediatrics across the "omic" spectrum, including at the genomic, transcriptomic, proteomic, microbiomic, and metabolomic level. The challenges to implementing salivary platforms into care, including the effects of age, diet, and developmental stage on salivary components, will be reviewed. Ultimately, large-scale, multicenter trials must be performed to establish normative biomarker values across the age spectrum to accurately discriminate between health and disease. Only then can salivary diagnostics truly translate into pediatric care.

Descriptive analysis of the masticatory and salivary functions and gustatory sensitivity in healthy children

OBJECTIVE

The objective of this study is to better understand salivary and masticatory characteristics, this study evaluated the relationship among salivary parameters, bite force (BF), masticatory performance (MP) and gustatory sensitivity in healthy children. The secondary outcome was to evaluate possible gender differences.

MATERIALS AND METHODS

One hundred and sixteen eutrophic subjects aged 7-11 years old were evaluated, caries-free and with no definite need of orthodontic treatment. Salivary flow rate and pH, total protein (TP), alpha-amylase (AMY), calcium (CA) and phosphate (PHO) concentrations were determined in stimulated (SS) and unstimulated saliva (US). BF and MP were evaluated using digital gnathodynamometer and fractional sieving method, respectively. Gustatory sensitivity was determined by detecting the four primary tastes (sweet, salty, sour and bitter) in three different concentrations. Data were evaluated using descriptive statistics, Mann-Whitney/t-test, Spearman correlation and multiple regression analysis, considering α = 0.05.

RESULTS

Significant positive correlation between taste and age was observed. CA and PHO concentrations correlated negatively with salivary flow and pH; sweet taste scores correlated with AMY concentrations and bitter taste sensitivity correlated with US flow rate (p < 0.05). No significant difference between genders in salivary, masticatory characteristics and gustatory sensitivity was observed. The regression analysis showed a weak relationship between the distribution of chewed particles among the different sieves and BF.

CONCLUSIONS

The concentration of some analytes was influenced by salivary flow and pH. Age, saliva flow and AMY concentrations influenced gustatory sensitivity. In addition, salivary, masticatory and taste characteristics did not differ between genders, and only a weak relation between MP and BF was observed.

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

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.