Exocyst subunits are involved in isoproterenol-induced amylase release from rat parotid acinar cells

Exocytosis of secretory granules in parotid acinar cells requires multiple events: tethering, docking, priming, and fusion with a luminal plasma membrane. The exocyst complex, which is composed of eight subunits (Sec3, Sec5, Sec6, Sec8, Sec10, Sec15, Exo70, and Exo84) that are conserved in yeast and mammalian cells, is thought to participate in the exocytotic pathway. However, to date, no exocyst subunit has been identified in salivary glands. In the present study, we investigated the expression and function of exocyst subunits in rat parotid acinar cells. The expression of mRNA for all eight exocyst subunits was detected in parotid acinar cells by RT-PCR, and Sec6 and Sec8 proteins were localized on the luminal plasma membrane. Sec6 interacted with Sec8 after 5 min of stimulation with isoproterenol. In addition, antibodies to-Sec6 and Sec8 inhibited isoproterenol-induced amylase release from streptolysin O-permeabilized parotid acinar cells. These results suggest that an exocyst complex of eight subunits is required for amylase release from parotid acinar cells.     

A novel role of probiotics in improving host defence of elite rugby union athlete: A double blind randomised controlled trial

ObjectiveTo examine the effects of a probiotic protocol on the incidence and severity of respiratory and gastrointestinal infections in elite rugby union athletes across an international competition season. Associations were also investigated between salivary biomarkers of stress (cortisol, alpha-amylase) and mucosal immunity (secretory(s)-IgA).DesignA double-blind RCT was conducted over 27-weeks, divided into three stages: (1) control period; (2) domestic competition; and (3) international competition.MethodsAthletes were assigned a probiotic (n = 9) or placebo (n = 10) supplement. Ultrabiotic 60™ or placebo was taken with food twice daily for 17 weeks and SB Floractiv™ 250 mg added twice daily during stage three.ResultsFive infections were diagnosed by the team sports physician across the 27-weeks, three within the intervention period in athletes randomised to the placebo group. No significant group x time interaction effects for salivary cortisol, alpha-amylase or s-IgA were identified over the 27-week time period, although a significant main effect for group and time was identified for salivary cortisol, alpha-amylase, and s-IgA (p < 0.05 for all). When considering stage, significant differences were identified in stage one with s-IgA lower in the probiotic group (p = 0.015). In stage two and three, salivary cortisol was higher in the probiotic group (p = 0.016 and p = 0.001 respectively), and salivary alpha-amylase was higher in the probiotic group in stage three (p = 0.007).ConclusionThe probiotic protocol used in this study was associated with an increase in salivary alpha-amylase supporting its possible role as a host defence peptide.     

Protein composition of whole and parotid saliva in healthy and periodontitis subjects

Cystatins are physiological inhibitors of cysteine proteinases and they are widely distributed in human tissues and body fluids including saliva. We previously reported an increased cystatin activity in whole saliva of gingivitis and periodontitis subjects. Based on this result we decided to investigate the type and origin of cystatins involved in this increased cystatin activity by collecting both whole and parotid saliva of 25 healthy and 30 periodontitis subjects. Saliva samples were quantified for cystatins S and C by enzyme-linked immunosorbent assay and cystatin activities were measured toward papain. Besides, three other salivary proteins were determined: the plasma protein albumin, the typical parotid derived amylase and the salivary immunoglobulin IgA. The present investigation shows that levels of total protein and cystatin activity as well as the levels of glandular derived proteins amylase and cystatin C were significantly higher in whole and parotid saliva of subjects with periodontitis than in healthy controls. Cystatin S, the major salivary cystatin. however was higher in the whole saliva of the healthy group. Whole saliva concentrations of albumin and IgA, originating from sources other than the glandular cells, were not different between healthy and periodontitis subjects and were also not correlated with the typical salivary gland proteins. In conclusion, this study provides additional evidence that the human salivary glands may respond to an inflammatory disease of the oral cavity, periodontitis, by enhanced synthesis of some acinar proteins.     

Complex Copy Number Variation of AMY1 does not Associate with Obesity in two East Asian Cohorts

The human amylase gene locus at chromosome 1p21.1 is structurally complex. This region contains two pancreatic amylase genes, AMY2B, AMY2A, and a salivary gene AMY1. The AMY1 gene harbors extensive copy number variation (CNV), and recent studies have implicated this variation in adaptation to starch‐rich diets and in association to obesity for European and Asian populations. In this study, we showed that by combining quantitative PCR and digital PCR, coupled with careful experimental design and calibration, we can improve the resolution of genotyping CNV with high copy numbers (CNs). In two East Asian populations of Chinese and Malay ethnicity studied, we observed a unique non‐normal distribution of AMY1 diploid CN genotypes with even:odd CNs ratio of 4.5 (3.3–4.7), and an association between the common AMY2A CN = 2 genotype and odd CNs of AMY1, that could be explained by the underlying haplotypic structure. In two further case–control cohorts (n = 932 and 145, for Chinese and Malays, respectively), we did not observe the previously reported association between AMY1 and obesity or body mass index. Improved methods for accurately genotyping multiallelic CNV loci and understanding the haplotype complexity at the AMY1 locus are necessary for population genetics and association studies.     

Giving support to others reduces sympathetic nervous system‐related responses to stress

Social support is a major contributor to the link between social ties and beneficial health outcomes. Research to date has focused on how receiving support from others might be good for us; however, we know less about the health effects of giving support to others. Based on prior work in animals showing that stimulating neural circuitry important for caregiving behavior can reduce sympathetic‐related responses to stressors, it is possible that, in humans, giving to others can reduce stressor‐evoked sympathetic nervous system responding, which has implications for health outcomes. To test the effect of giving support on the physiological stress response, participants either wrote a supportive note to a friend (support‐giving condition) or wrote about their route to school/work (control condition) before undergoing a standard laboratory‐based stress task. Physiological responses (heart rate, blood pressure, salivary alpha‐amylase, salivary cortisol), and self‐reported stress were collected throughout the protocol. In line with hypotheses, support giving (vs. control) reduced sympathetic‐related responses (systolic blood pressure and alpha‐amylase) to the stressor. No effects of support giving were found on self‐reported psychological stress or cortisol levels. Results add to existing knowledge of the pathways by which support giving may lead to health benefits and highlight the contribution of giving to others in the broader social support‐health link.     

Changes of free radicals and digestive enzymes in saliva in cases with deficiency in spleen-yin syndrome

Objective: To explore the nature of deficiency in spleen-yin syndrome, which could provide scientific theoretical support and practical guidance for clinical Traditional Chinese Medicine (TCM) syndrome differentiation based on biology, and had a strong clinical significance. Methods: Serum Cu and Zn were detected by atomic absorption spectrophotometer, serum vitamin E by high performance liquid chromatography, serum vitamin C by 2,4-Dinitrophenylhydrazine Colorimetry, total superoxide dismutase (SOD) and Cu and Zn-SOD by the xanthine oxidase method, and malondialdehyde (MDA) by the 2-thiobarbituric acid method (TBA). Total antioxidant capacity was detected by a colorimetry kit. Amylase Activity was detected by an automatic biochemical analyzer. Lysozyme was detected by lysozyme detection plate, the diameter of bacteriolysis circle was measured and the corresponding content of lysozyme was obtained from a table of standard curve values. Results: No significant difference in total SOD and Cu, Zn-SOD was found between deficiency in spleen-yin group and normal group. However, such factors in deficiency in kidney-yin group were significantly lower than the other groups (P < 0.05). The MDA content in both deficiency in spleen-yin group and deficiency in kidney-yin group were significantly higher than that of normal group (P < 0.05), while the total antioxidant capacity was significantly lower than normal group (P < 0.05). The vitamin E content in deficiency in kidney-yin group was significantly lower than that in the other two groups (P < 0.05). No significant difference in the contents of vitamin C, Cu and Zn were observed in these groups. The Zn/Cu level in deficiency in kidney-yin group and the vitamin E level in deficiency in spleen-yin group decreased, but with no significant difference. Amylase activity in unit time in cases with deficiency in spleen-yin was lower than and had significant differences with that in normal cases, and higher than that in cases with deficiency in kidney-yin. The sectional velocity of saliva and the ratio of lysozyme in normal case group were significantly higher than other two groups, while deficiency in the spleen-yin group was significantly higher than the deficiency in kidney-yin group. Conclusion: All the results indicated that the objective pathological mechanism between the deficiency in spleen-yin and deficiency in kidney-yin was different.     

Association of blood pressure and antihypertensive drugs with diurnal alpha-amylase activity

Salivary α-amylase (sAA) has been proposed as a marker of autonomic activity, but its association with blood pressure and antihypertensive drugs (AD) is unknown. Basal sAA rhythm was assessed immediately after awakening, 30 min after awakening, 11 am, 3 pm, and 8 pm in 78 older adults. Profiles differed significantly between men and women, with men lacking the typical decrease of sAA in the morning and showing more pronounced alterations throughout the day. A higher total output of sAA was found in individuals not using AD or being hypertensive, and especially pronounced in hypertensive individuals not using AD. These data indicates a difference between normotensives and hypertensives and an association of AD with characteristics of diurnal amylase. Findings highlight the usefulness of sAA as an index of autonomic imbalance in disease, and indicate sAA as a promising candidate to non-invasively study therapeutic treatment effects.