Salivary Reseach News

New book explores foundations of salivary bioscience

April 13, 2020 by IISBR

“Salivary Bioscience” reveals foundation of knowledge of a high-impact interdisciplinary field

“If ever there was a time when monitoring infectious disease exposure was a hot topic, it is now.” Referencing his colleague Chris Heaney, associate professor in the Department of Environmental Health, Bloomberg School of Public Health at Johns Hopkins University, UC Irvine Chancellor’s Professor Douglas A. Granger says in a recent interview, “Before this most recent outbreak [of coronavirus] was dominating the news, our collaborative research efforts were focused on monitoring exposure to infectious diseases in population settings.”

Heaney’s research group uses saliva as a minimally invasive alternative biospecimen to blood sampling, which is why “The Utility of Antibodies in Saliva to Measure Pathogen Exposure and Infection” is Chapter 13 of “Salivary Bioscience: Foundations of Interdisciplinary Saliva Research and Applications,” which was edited by Granger and Marcus K. Taylor, a UCI faculty affiliate and American College of Sports Medicine Fellow.

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Reactivity of Salivary Uric Acid in Response To Social Evaluative Stress in African Americans.

March 30, 2020 by IISBR

Background: High uric acid (UA) is associated with hypertension and cardiovascular disease (CVD), both of which occur disproportionately among African Americans. High UA also predicts greater blood pressure reactivity responses to acute social stress. However, whether UA itself shows reactivity in response to stress is unknown. We evaluated salivary uric acid (sUA) and blood pressure reactivity in response to acute social stress. Healthy African Americans (N = 103; 32% male; M age = 31.36 years), completed the Trier Social Stress Test. sUA and blood pressure measurements were taken before, during and after the stressor task. sUA showed significant reactivity and recovery, especially among older African Americans. Total sUA activation was also associated with systolic and diastolic blood pressure total activation. Findings illuminate that acute stress may be a way in which UA is implicated in hypertension and CVD, suggesting a critical need to explore UA reactivity as a novel parameter of the acute stress response.

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Evaluation of Biochemical and Epigenetic Measures of Peripheral Brain-Derived Neurotrophic Factor (BDNF) as a Biomarker in Huntington’s Disease Patients

March 7, 2020 by IISBR

Background: Huntington’s disease (HD) is an autosomal-dominant neurodegenerative movement disorder that presents with prominent cognitive and psychiatric dysfunction. Brain-derived neurotrophic factor (BDNF) plays an important role in the pathophysiology of HD, as well as other neurodegenerative and psychiatric disorders, and epigenetic alterations in the complex BDNF promoter have been associated with its deregulation in pathological conditions. BDNF has gained increased attention as a potential biomarker of disease; but currently, the conflicting results from measurements of BDNF in different biofluids difficult the assessment of its utility as a biomarker for HD. Here, we measured BDNF protein levels in plasma (n = 85) and saliva (n = 81) samples from premanifest and manifest HD patients and normal controls using ELISA assays. We further examined DNA methylation levels of BDNF promoter IV using DNA derived from whole blood of HD patients and healthy controls (n = 40) using pyrosequencing. BDNF protein levels were not significantly different in plasma samples across diagnostic groups. Plasma BDNF was significantly correlated with age in control subjects but not in HD patients, nor were significant gender effects observed. Similar to plasma, salivary BDNF was correlated with age only in control subjects, with no gender effects observed. Importantly, we detected significantly lower levels of salivary BDNF in premanifest and manifest HD patients compared to control subjects, with lower BDNF levels being observed in premanifest patients within a predicted 10 years to disease onset. Salivary and plasma BDNF levels were not significantly correlated with one another, suggesting different origins. DNA methylation at four out of the 12 CpG sites studied in promoter IV were significantly altered in HD patients in comparison to controls. Interestingly, methylation at three of these CpG sites was inversely correlated to the Hospital Anxiety and Depression Scale (HADS) scores. BDNF promoter methylation was not correlated with motor or cognitive scores in HD patients, and was not associated with sex or age in neither disease nor control groups. Conclusion: Our studies show that BDNF protein levels are decreased in saliva; and BDNF promoter methylation increased in blood in HD subjects when compared to controls. These findings suggest that salivary BDNF measures may represent an early marker of disease onset and DNA methylation at the BDNF promoter IV, could represent a biomarker of psychiatric symptoms in HD patients.

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Is Crime Bad for Your Health? The Link Between Delinquent Offending and Cardiometabolic Risk

March 1, 2020 by IISBR

Background: Specific sources of psychophysiological dysfunction have been identified as a primary mechanism of the association between stress and health, wherein chronic and prolonged exposure to stressors results in downstream negative consequences of stress-linked dysregulation that increase the likelihood of chronic health problems. Factors pertinent to criminological inquiry have been previously identified as sources of physiological dysfunction, but the extent to which offending over the life course operates in a similar manner has yet to be examined. The current study examines the longitudinal association between delinquency and physiological dysfunction in cardiovascular and metabolic functioning (i.e., cardiometabolic risk). The results of longitudinal structural equation models revealed that greater levels of delinquency are associated with higher levels of cardiometabolic risk.

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Emotional Processing Coping Methods and Biomarkers of Stress in Young Adult Testicular Cancer Survivors

February 12, 2020 by IISBR

Background: Coping through emotional processing (EP) with cancer-related circumstances can take several forms, including methods thought to be constructive (e.g., planning, meaning making) and unconstructive (e.g., rumination). These forms can have differential relationships with experiences of stress. Associations of coping through constructive and unconstructive EP in expressive writing with salivary stress biomarkers were examined among young adult testicular cancer survivors. Constructive processing was significantly associated with less overall daily cortisol output and smaller salivary alpha-amylase awakening response; unconstructive processing was also associated with lower daily cortisol output. These preliminary results from this exploratory study inform future research associating emotion-regulation coping and biological stress reactivity.

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Sleep Quality in Young Adult Informal Caregivers: Understanding Psychological and Biological Processes

February 10, 2020 by IISBR

BACKGROUND:

Providing informal care for a relative or friend with medical or mental needs can extol a physical burden on the caregiver, including impaired aspects of sleep quality such as suboptimal sleep duration, lengthened sleep latency, frequent awakenings, daytime sleepiness, and poor self-rated sleep quality. Diminished sleep quality can worsen the health in the caregiver, including dysregulation of hypothalamic-pituitary-adrenal axis (HPA) activity. Few studies have attempted to describe sleep in young adults who provide regular informal care. This study examines subjective and objective indicators of sleep quality and diurnal cortisol rhythms among young adult caregivers relative to non-caregiving peers. We expect that caregivers will exhibit poorer objective and subjective sleep quality and greater dysregulation in diurnal cortisol indices, than demographically similar non-caregivers, and that caregivers with poorer sleep will exhibit pronounced cortisol dysregulation.

METHODS:

Participant self-reported sleep quality over the prior month via the Pittsburgh Sleep Quality Index and objective sleep quality was observed via wrist actigraph for three consecutive days. Diurnal salivary cortisol was also measured across the three days of actigraph monitoring.

RESULTS:

Informal caregivers exhibited more self-reported sleep disturbance and greater sleep latency than non-caregivers, as well as more objectively measured sleep fragmentation. Caregivers with a shorter sleep duration were observed to have flatter diurnal cortisol slopes than caregivers with a relatively longer sleep duration.

CONCLUSIONS:

Young adult caregivers appear to be at risk for impairment in sleep quality, which in turn might impact health through HPA axis dysregulation. Longitudinal research is needed to identify these relationships across time.

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Salivary total Immunoglobulin G as a surrogate marker of oral immune activity in salivary bioscience research

December 14, 2019 by IISBR

Background: The integration of salivary biomeasures in biobehavioral, psychophysiological, and clinical research has greatly expanded our ability to study the biopsychosocial processes underlying health. Much of this research, however, has failed to adequately assess and adjust for the impact of oral immune activity on salivary biomeasure concentrations and associations with serum levels. Aiming to improve the validity and reliability of salivary biomeasure data, we examine salivary total Immunoglobulin G (IgG) as a potential surrogate marker of oral inflammation and immune activity. During a single study visit in Baltimore, Maryland, healthy young adult participants provided matched blood and saliva samples (N=99; age 18–37 years, 42% female) and completed an oral health questionnaire. Biospecimens were assayed for total IgG and immune markers related to inflammation (cytokines), blood in saliva (transferrin), and tissue remodeling (matrix metalloproteinase-8). Total IgG (μg/mL) concentrations were higher in serum than saliva. Salivary total IgG was associated with some self-reported oral health measures, and strongly positively associated with all salivary immune markers. Controlling for salivary total IgG may be a feasible, affordable approach to adjusting salivary biomeasure findings for the influence of the oral immune environment when it is not possible or practical to obtain clinical oral health data.

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Long-Term Associations Between Prenatal Maternal Cortisol and Child Neuroendocrine-Immune Regulation.

November 20, 2019 by IISBR

Background:

Advancing understanding of the developmental origins of neuroendocrine-immune (NEI) functioning is key to elucidating the biological mechanisms involved in health and disease risk across the lifespan. This study examined whether prenatal maternal hypothalamic-pituitary-adrenal (HPA) activity moderates child NEI relations and explored the consistency of this moderating effect across gestation.

Methods:

Pregnant women participated in five prenatal study visits from 24 to 38 weeks gestation. At each visit, women provided a saliva sample. In a 5-year follow-up study, children (n_female = 25, n_male=20) provided four saliva samples and participated in behavioral assessments and challenge tasks. Prenatal maternal saliva samples were assayed for cortisol. Child saliva samples were assayed for cortisol and cytokines (IL-1β, IL-6, IL-8, TNFα) as indices of HPA and inflammatory activity. Multilevel mixed-effects models examined the moderation of child NEI relations by prenatal maternal cortisol.

Results:

Among males, average prenatal maternal cortisol did not moderate child NEI relations. Among females, average prenatal maternal cortisol moderated some child NEI relations with higher prenatal cortisol associated with more positive cortisol-cytokine relations at age five. When examined by gestational time point, there were more significant NEI moderation effects by maternal cortisol from later gestation (≥ 30 weeks) than earlier.

Conclusions:

The findings suggest prenatal maternal HPA activity may moderate child NEI functioning. Additional research conducted with more heterogeneous and larger samples is needed to fully understand these relations. Furthering our knowledge of NEI development has important research and clinical implications, particularly for understanding and addressing conditions with inflammatory pathophysiologies, such as depression and cardiovascular disease.

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Overestimating Self-Blame for Stressful Life Events and Adolescents’ Latent Trait Cortisol: The Moderating Role of Parental Warmth

November 5, 2019 by IISBR

Background: Cognitive interpretations of stressful events impact their implications for physiological stress processes. However, whether such interpretations are related to trait cortisol-an indicator of individual differences in stress physiology-is unknown. In 112 early adolescent girls (M age = 12.39 years), this study examined the association between self-blame estimates for past year events and latent trait cortisol, and whether maternal warmth moderated effects. Overestimating self-blame (versus objective indices) for independent (uncontrollable) events was associated with lower latent trait cortisol, and maternal warmth moderated the effect of self-blame estimates on latent trait cortisol for each dependent (at least partially controllable) and interpersonal events. Implications for understanding the impact of cognitive and interpersonal factors on trait cortisol during early adolescence are discussed.

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