Salivary alpha amylase and cortisol responses to different stress tasks: Impact of sex

Neuro-endocrine markers such as salivary alpha amylase (sAA) and cortisol (CORT) play an important role in establishing human responses to stressful events. Whereas sAA levels reflect sympathetic system activity, salivary cortisol appears to be a valid measure for HPA axis activity. Although many studies looked at either sAA or CORT responses in reaction to stress, work still has to be done to look at the way these systems interact, especially when both systems are activated. Additionally, sex effects in CORT responses have been investigated relatively often, but possible sex differences in sAA levels and responses, or the way both systems interact has not been the focus of sufficient studies to yield a univocal conclusion. In this study we presented a group of healthy participants (n=80) with two mildly stressful tasks, consisting of an aversive picture rating task and a cold pressor stress (CPS) task. The second task was compared with a control task. We expected a rise in sAA level in response to the first task and sAA as well as CORT responses on the second task and explored the interaction between the two responses. Results indicate that sAA is indeed a sensitive marker in both psychologically and physically induced arousal paradigms, whereas a cortisol response was only observed in the CPS task. Men had higher sAA levels than women during the complete course of the study, but men and women were comparable in their responsivity to the tasks. No strong correlations between sAA and CORT responses were found.     

Hair cortisol levels as a retrospective marker of hypothalamic-pituitary axis activity throughout pregnancy: comparison to salivary cortisol

Maternal stress during pregnancy is associated with negative maternal/child outcomes. One potential biomarker of the maternal stress response is cortisol, a product of activity of the hypothalamic-pituitary-adrenal axis. This study evaluated cortisol levels in hair throughout pregnancy as a marker of total cortisol release. Cortisol levels in hair have been shown to be easily quantifiable and may be representative of total cortisol release more than single saliva or serum measures. Hair cortisol provides a simple way to monitor total cortisol release over an extended period of time. Hair cortisol levels were determined from each trimester (15, 26 and 36 weeks gestation) and 3 months postpartum. Hair cortisol levels were compared to diurnal salivary cortisol collected over 3 days (3 times/day) at 14, 18, 23, 29, and 34 weeks gestational age and 6 weeks postpartum from 21 pregnant women. Both salivary and hair cortisol levels rose during pregnancy as expected. Hair cortisol and diurnal salivary cortisol area under the curve with respect to ground (AUCg) were also correlated throughout pregnancy. Levels of cortisol in hair are a valid and useful tool to measure long-term cortisol activity. Hair cortisol avoids methodological problems associated with collection other cortisol measures such as plasma, urine, or saliva and is a reliable metric of HPA activity throughout pregnancy reflecting total cortisol release over an extended period.     

Use of cortisol as a stress marker: Practical and theoretical problems

Human biologists have shown increasing interest in the use of cortisol as an objective marker of stress in recent years. This paper reviews both practical and theoretical problems raised by this approach. The methodology of cortisol assessment using urine, saliva, and plasma is considered. There are many practical problems involved in obtaining good measures of cortisol, although the availability of salivary assays offers a promising way forward. Theoretical issues are of greater concern. Results of laboratory studies led to the hypothesis that cortisol is elevated when an individual is distressed. However, relatively little work has been done on cortisol variation in “real life,” and the results of such studies do not, in general, conform to this hypothesis. It is concluded that the determinants of cortisol variation are not well understood. For example, cortisol level may be as much influenced by positive emotions as by negative emotions usually identified with stress. Further documentation of cortisol variation in everyday life is needed, and at present it is premature to use cortisol level as a marker of stress. © 1995 Wiley-Liss, Inc.     

Methodological considerations in the use of salivary α‐amylase as a stress marker in field research

Salivary α‐amylase recently has been identified as a stress‐related biomarker for autonomic nervous system activity. This study addresses sample collection and handling considerations for field researchers. Saliva was collected by unstimulated passive drool from 14 adults and pooled. Incubation of pooled saliva at 22 or 37°C for 21 days did not diminish amylase activity. However, sodium azide added at concentrations ≤1.12 mg/ml to pooled saliva artificially inflated activity. After dosing cotton rolls within Salivette saliva collection devices with 0.25 to 1.5 ml of unpooled passive drool saliva from six additional adults, recovery of amylase activity was significantly below 100% at all volumes, with increased variance in recovery when the cotton was incompletely saturated (≤1.0 ml). Hence, collection by passive drool instead of cotton‐containing devices for amylase determinations is recommended, particularly whenever it is impossible to ensure full, uniform cotton saturation, and azide should be avoided as a preservative. Am. J. Hum. Biol., 2008. © 2008 Wiley‐Liss, Inc.     

The feasibility of ambulatory biosensor measurement of salivary alpha amylase: Relationships with self-reported and naturalistic psychological stress

Recent developments in biosensor technology allow point-of-use reporting of salivary alpha amylase (sAA) levels while approaching the precision and accuracy of conventional laboratory-based testing. We deployed a portable prototype sAA biosensor in 54 healthy, male dental students during a low stress baseline and during final exams. At baseline, participants completed the Brief Symptom Inventory (BSI). At baseline and the exam week, participants provided saliva samples at 10 AM, 1 PM, and 5 PM, and rated concurrent subjective distress. Although subjective distress was higher during exams compared to baseline, sAA levels did not differ between baseline and exams. Higher sAA levels were related to higher concurrent subjective distress, and higher depressive and social isolation symptoms on the BSI were related to lower sAA during exams. Results from this study, in combination with previous validation data, suggest that the sAA biosensor is a promising tool for point-of-use measures of exposure to stress.     

The effect of stress on salivary cortisol in panic disorder patients.

BACKGROUND: Various findings suggest the possibility of an abnormal cortisol response to CRH in panic disorder patients, which raises the question of whether such patients might also produce an abnormal cortisol response to stress. The purpose of the present study was to use salivary cortisol measurement in assessing differences in response to novelty/mild stress situations between panic disorder subjects and controls. METHODS: Subjects were recruited by means of posters and subsequently screened for suitability as controls or panic subjects. Twenty-four panic disorder (PD) sufferers and 15 panic-free control subjects were tested on a range of psychometric and physiological measures, at both the start and the end of the experiment. Subjects were tested at the beginning for state anxiety, salivary cortisol, heart rate, and blood pressure, and these tests were repeated at the end of the session (which had been designed to promote reassurance). RESULTS: The state anxiety scores (STAI) showed a reduction in anxiety level over the test period, and there was a corresponding fall in both blood pressure and heart rate for both groups. Cortisol levels also fell over the course of the interview in the control group, but in the PD group cortisol levels showed no such reduction. In addition, there was a significant difference in the levels of cortisol at the start of the session between the two groups (PD group lower). CONCLUSIONS: These data indicate a possible alteration in cortisol responsiveness to stress/novelty situations in PD subjects. This was considered to be consistent with previous suggestions of HPA axis dysregulation in PD patients, although our research indicates unresponsiveness rather than responsiveness to be a factor to be considered for future investigation. CLINICAL IMPLICATIONS: Our results suggest that not all subjects suffering PD may benefit from stress reduction therapies as a first choice of treatment for their panic attacks. The existence of nocturnal panic attacks (considering sleep as a combination of mental and physical relaxation), in the absence of nightmares, as well as the induction of panic attacks during relaxation support this view. LIMITATIONS OF THE STUDY: Apart from the difficulty in accessing sufficient symptomatic subjects, the induction of higher levels of stress could be useful for confirmation of these results. However, this requires specialist support in case of subjects developing panic attacks during the experiments, which was not available during the present study. SUMMARY: Twenty-four panic disorder (PD) sufferers and 15 panic-free control subjects were tested on a range of psychometric and physiological measures, at both the start and the end of an experimental session. Subjects were tested at the beginning for state anxiety, salivary cortisol, heart rate, and blood pressure, and these tests were repeated at the end of the session. The state anxiety scores (STAI) showed a reduction in anxiety level over the test period for both groups, and there was a corresponding fall in both blood pressure and heart rate. Cortisol levels also fell over the course of the session in the control group, but in the PD group cortisol levels showed no such reduction. In addition, there was a significant difference in the levels of cortisol at the start of the session between the two groups (PD group lower). These data indicate a possible alteration in cortisol responsiveness to stress/novelty situations in PD subjects. This was considered to be consistent with previous suggestions of HPA axis dysregulation in PD patients, although our research indicates unresponsiveness rather than responsiveness to be a factor to be considered for future investigation.     

考试应激对唾液皮质醇及SIgA的影响

本研究以某校高二在校６０名男性学生为研究对象，以期末考试为应激源，采用自身对照方法，研究了考试应激对学生唾液中ＳＩｇＡ（分泌型免疫球蛋白Ａ）及皮质醇影响，并对该组学生进行了ＥＰＱ测定，结果表明考试应激期间唾液ＳＩｇＡ值较考前有明显下降，考试期间唾液皮质醇值较考前有明显上升（Ｐ＜０．０１）；Ｎ维度和ＳＩｇＡ下降率及皮质醇上升率呈显著水平相关（Ｐ＜０．０１）。     

Postmortem prolactin as a marker of antemortem stress

AIM: To determine whether raised prolactin concentrations could be identified using postmortem venous blood and whether the level of prolactin correlated with antemortem stress. METHODS: Blood was obtained from the right femoral vein of 100 random adult necropsy cases, all of whom had been dead less than four days. Prolactin was determined in the samples by microparticle immunoassay. The levels of prolactin obtained were then analysed in relation to sex and cause of death, with particular emphasis on a history of antemortem stress and drug use. RESULTS: Prolactin in all cases of trauma was in the normal range (up to 500 mU/l). In cases of sudden unexpected deaths the mean concentration was 533 mU/l (95% confidence interval (CI), 372 to 694 mU/l). Postoperative deaths or cases with chronic disease had a mean value of 1027 mU/l (95% CI, 735 to 1319 mU/l). Cases of suicide had a mean value of 1398 mU/l. Analysis of the suicides by sex showed a significant difference, the mean in female cases being 2072 mU/l compared with 692 mU/l in male cases. In three of the four female suicides with the highest prolactin, the hyperprolactinaemia might have been attributable to a drug effect, but one case still had unexplained hyperprolactinaemia. CONCLUSIONS: It is possible to detect prolactin reliably in postmortem venous blood samples. Prolactin values at necropsy differ according to the cause of death, with markedly higher values in postoperative deaths and in the chronically ill. Hyperprolactinaemia in cases of suicide is likely to result from the effects of the drugs used, but the levels were higher than previously reported.     

Hair cortisol as a measure of the stress response to social adversity in young children

Hair cortisol has the potential to provide insight into young children's long-term stress response to social adversity. This study investigated associations between children's exposure to adversity from pregnancy to 2 years of age and their hair cortisol at 2 years, using a longitudinal cohort of children enriched for adversity risk, whose mothers were recruited during pregnancy through the “right@home” trial. Exposures were 18 maternal socioeconomic and psychosocial indicators of adversity, examined as concurrent, cumulative, and longitudinal exposure from pregnancy to 2 years. Hair samples were analyzed from 319/603 (53%) children participating at 2 years. Multivariable regression analyses for concurrent exposure showed three indicators of adversity were associated with higher hair cortisol (housing tenure of public rental, paying board or living rent free; not living in a safe place; higher maternal stress symptoms), one with lower hair cortisol (housing problems), and 14 indicators with no evidence of association. There was no evidence of association for the cumulative adversity count. Longitudinal exposure showed “intermittent” and “persistent” high maternal stress symptoms were associated with higher hair cortisol. The small number of associations identified suggests that hair cortisol is limited as a measure of stress response to social adversity in children at 2 years.     

Investigating the role of perceived stress on bacterial flora activity and salivary cortisol secretion: a possible mechanism underlying susceptibility to illness

This study examined the impact of academic stress on salivary cortisol concentrations and lactic acid bacteria activity. Whole, unstimulated saliva samples and faecal samples were collected from 23 healthy undergraduate students (23.0+/-6.8 years; range 18-44) over two 1-week periods: during the beginning of semester (low-stress baseline condition) and during the first week of exams (high-stress condition). Students also completed a series of questionnaires measuring perceived levels of stress, gastrointestinal symptoms, and nutritional intake. Significant findings indicated that faecal lactic acid bacterial levels were lower during the high-stress condition. Paralleling this, students rated perceived levels of stress as being greater during the exam period compared to the baseline condition. The findings from this study have provided further insight into the link between stress and gastrointestinal flora activity in humans.     

The effects of examination stress on salivary cortisol, immunoglobulin A, and chromogranin A in nursing students

This study aimed to assess the effects of examination stress on salivary cortisol, immunoglobulin A (IgA), and chromogranin A (CgA) in nursing students. Saliva samples were collected from 15 healthy females before and immediately after the one-hour examination, and two hours after the examination. Salivary cortisol, IgA, and CgA concentrations were determined by enzyme-linked immunosorbent assay. Both IgA and CgA concentrations statistically increased immediately after the examination (P < 0.05) and decreased two hours after the examination. No significant differences were observed between before and after the examination in the salivary cortisol concentration. These findings suggest that the acute stress due to the examination is associated with raised salivary IgA and CgA, but not cortisol.     

中性粒细胞与淋巴细胞比值联合检测纤维蛋白原对结直肠癌预后的判断价值

目的: 探讨中性粒细胞与淋巴细胞比值(NLR)和纤维蛋白原(Fibrinogen,FIB)联合形成指标FIB-NLR 在结直肠癌预后中的临床意义。方法:回顾性分析我院2010 年6 月至2011 年6 月接受手术治疗的250 例结直肠癌患者的临床资料,分别分析NLR 和FIB 与结直肠癌的病理特征的关系,将NLR 与FIB 进行联合形成一个指标(FIB-NLR)。将250 名结直肠癌患者分为3 组,患者NLR逸2.95 及FIB逸348 mg/ dl 定为FIB-NLR 2 分组,NLR逸2.95 及FIB<348 mg/ dl 或者NLR<2.95 及 FIB逸348 mg/ dl 定为1 分组,NLR<2.95 及FIB<348 mg/ dl 为0 分组,并分析3 组患者在结直肠癌的浸润深度、分期、淋巴结转移、神经浸润、远处转移、组织学分级中是否具有差异性。并将3 组患者按生存时间做生存分析,并对3 组患者的生存率进行比较。结果:中晚期及有淋巴结转移结直肠癌患者NLR 值明显高于分期较早及无淋巴结转移患者的NLR,差异具有统计学意义(P<0.001),肿瘤浸润深度较深、有神经浸润、有远处转移的患者其NLR 值明显高于浸润深度较浅、无神经浸润、无远处转移患者的NLR 值,差异具有统计学意义(P =0.006、P =0.002、P =0.007)。中晚期、有淋巴结转移、有远处转移的结直肠癌患者其FIB 值明显高于早期及无淋巴结转移、无远处转移的结直肠癌患者的FIB 值,差异具有统计学意义(P<0.001),浸润深度越深及有神经浸润的结直肠癌患者FIB 值明显高于浸润深度浅及无神经浸润患者的FIB 值,差异具有统计学意义(P =0.015、P=0.012)。NLR 与FIB 均在肿瘤的组织学分级、年龄大小、性别肿瘤部位无明显关联(P>0.05)。结直肠癌的临床分期越晚、浸润深度越深、有淋巴结转移、有远处转移、有神经浸润的患者其FIB-NLR 评分较早期、浸润深度浅、无淋巴结转移及无远处转移、无神经浸润患者高,差 异具有统计学意义(P<0.001)。生存分析发现,评分越高组其5 年生存率越低,差异具有统计学意义(P =0.001)。结论:FIB-NLR 可能是一个潜在的判断结直肠癌进展及预后的有效指标。     

Pili of oral Streptococcus sanguinis bind to salivary amylase and promote the biofilm formation

Streptococcus sanguinis is a member of oral streptococci and one of the most abundant species found in oral biofilm called dental plaque. Colonization of the oral streptococci on the tooth surface depends on the adhesion of bacteria to salivary components adsorbed to the tooth surface. Recently, we identified unique cell surface long filamentous structures named pili in this species. Herein, we investigated the role of S. sanguinis pili in biofilm formation. We found that pili-deficient mutant, in which the genes encoding the three pilus proteins PilA, PilB and PilC have been deleted, showed an impaired bacterial accumulation on saliva-coated surfaces. Confocal microscopic observations suggested that the mutant was incapable of producing typical three-dimensional layer of biofilm. Ligand blot analysis showed that the ancillary pilus proteins PilB and PilC bound to human whole saliva. Additional analysis demonstrated that PilC bound to multiple salivary components, and one of which was found to be salivary α-amylase. These results indicate that pilus proteins are members of saliva-binding proteins of oral S. sanguinis, and suggest the involvement of pili in its colonization on saliva-coated tooth surfaces and in the human oral cavity.     

The sound of stress: blunted cortisol reactivity to psychosocial stress in tinnitus sufferers

Clinical observations suggest that tinnitus is modulated by stress. However, there is little empirical data to support the link between stress and tinnitus. In this study, we measured the stress hormone cortisol to examine the reactivity of the hypothalamic-pituitary-adrenal (HPA) axis in tinnitus participants as well as in healthy controls without tinnitus. Eighteen participants with tinnitus and 18 controls without tinnitus were exposed to the Trier Social Stress Task and cortisol sampling and subjective ratings were obtained at regular intervals. Tinnitus participants displayed a blunted cortisol response to psychosocial stress, in comparison with healthy controls who had a typical cortisol release about 30 min after the beginning of the experiment. The blunted cortisol response displayed by the tinnitus participants suggests that they have an anomaly along the HPA axis. Their cortisol response is similar to that found in other bodily stress-related diseases and thus suggests that tinnitus is related to stress. However, tinnitus intensity might not be modulated by stress in a concurrent manner.     

Epithelial membrane antigen as a marker of human salivary gland acinar and ductal cell function

Monoclonal antibody to epithelial membrane antigen (EMA) from human milk fat globule membrane was used with the immunoperoxidase method to examine the distribution of EMA in normal human salivary glands and in their obstructive lesions. EMA staining in the normal salivary gland was limited to luminal and lateral borders of acinar cells. The antigen was also present in high concentration on the luminal side of ductal cells. In obstructive lesions or sialoadenitis, lateral border and luminal positive staining in atrophic acinar cells was reduced or absent, and the EMA staining in duct-like structures was also markedly decreased on even absent in chronic stage. The degree of reduction in EMA staining was dependent on the extent of degeneration. Expression of immunohistochemically detectable EMA in paraffin sections suggests the antigen to be useful as a new marker of salivary gland function, of either acinar compartments or ductal segments.     

The linkage relationships of the haemoglobin beta, delta and alpha loci with 34 genetic marker systems

An analysis of the linkage relationships of the Hb_α, and Hb_β, loci with 34 genetic marker systems is presented. No evidence of linkage of either haemoglobin locus with any of the marker loci was found. The Hb_α, locus may be excluded from approximately 7% and the Hb_β, locus from approximately one-third of the autosomal genome.     

Children's and adults' salivary alpha‐amylase responses to a laboratory stressor and to verbal recall of the stressor

Salivary alpha‐amylase (sAA), an enzyme produced by the salivary glands, increases in response to physical and psychosocial stressors in adults. Whether similar increases are evident among children, though, is less clear, and there is a lack of studies directly comparing children's and adults' sAA responses to an identical stressor. In this study, 24 children (9–12 years; 12 female) and 26 adults (18–23 years; 16 female) were exposed to an identical psychosocial laboratory stressor and a recall interview regarding that stressor after a 2‐week delay. Saliva was collected before and 1, 10, 20, and 30 min after the stressor/recall interview. Among adults, concentrations of sAA increased on both study days, but similar increases were not detected among children. Findings suggest developmental differences in sAA reactivity, and underscore the need to characterize the confluence of elements that will reliably elicit sAA responses to mild stress in youth. © 2010 Wiley Periodicals, Inc. Dev Psychobiol 52: 598–602, 2010.