Human saliva as a tool to investigate intimate partner violence

Saliva as a diagnostic tool to measure polycyclic aromatic hydrocarbon exposure in dental patients exposed to intimate partner violence (IPV)

BACKGROUND

Social habits such as tobacco use, alcohol consumption, and chemically contaminated diet contribute to poor oral health. Intimate Partner Violence (IPV) is a global public health epidemic which can exacerbate the prevalence of health conditions affecting a victim's lifespan. This study investigates using saliva as a biomarker for detecting levels of benzo(a)pyrene [B(a)P]; a toxicant present in cigarette smoke and barbecued meat in a population of IPV + female patients.

METHODS

A cross-sectional IRB-approved study utilized 63 female participants (37 African Americans [AA], and 26 non-African Americans [NAA]), who provided consent for the study. Participants submitted samples of saliva, as well as questionnaires about demographics, health history, and a well-validated (IPV) screen.

RESULTS

The prevalence of IPV was greater in AA compared to NAA. While the concentrations of PAHs/B(a)P detected in saliva of IPV samples in NAA were generally within the range of B(a)P reported for saliva from elsewhere, the concentrations were high in some IPV positive samples. Among the B(a)P metabolites, the concentrations of B(a)P 7,8-diol, B(a)P 3,6- and 6,12-dione metabolites were greater than the other metabolite in both AA and non-AA groups who were positive.

CONCLUSION

Our study supports the use of saliva as a potential "diagnostic rheostat" to identify toxicants that may exacerbate/precipitate systemic disease in female victims of IPV. In addition, our study is the first to report that IPV may precipitate the accumulation of B(a)P in oral cavity that can alter inflammatory cascades and increase risk of poor health outcomes in this population of patients.

Investigation of Whole and Glandular Saliva as a Biomarker for Alzheimer’s Disease Diagnosis

Salivary Aβ40, Aβ42, t-tau, and p-tau 181 are commonly employed in Alzheimer’s disease (AD) investigations. However, the collection method of these biomarkers can affect their levels. To assess the impact of saliva collection methods on biomarkers in this study, 15 healthy people were employed in the morning with six saliva collection methods. The chosen methods were then applied in 30 AD patients and 30 non-AD controls. The levels of salivary biomarkers were calculated by a specific enzyme-linked immunosorbent assay. The receiver operating characteristic was utilized to assess salivary biomarkers in AD patients. The results demonstrated that the highest levels of salivary Aβ40, Aβ42, t-tau, and p-tau were in different saliva collection methods. The correlations between different saliva biomarkers in the same collection method were different. Salivary Aβ40, Aβ42, t-tau, and p-tau had no significant association. Salivary Aβ42 was higher in AD than in non-AD controls. However, p-tau/t-tau and Aβ42/Aβ40 had some relevance. The area under the curve for four biomarkers combined in AD diagnosis was 92.11%. An alternate saliva collection method (e.g., USS in Aβ40, UPS in Aβ42, t-tau, SSS in p-tau 181) was demonstrated in this study. Moreover, combining numerous biomarkers improves AD diagnosis.

Influence of Intimate Partner Violence (IPV) Exposure on Cardiovascular and Salivary Biosensors: Is There a Relationship?

BACKGROUND/PURPOSE

Intimate partner violence (IPV) is a global public health epidemic that initiates/exacerbates health consequences affecting a victim's lifespan. IPV can significantly predispose women to a lifetime risk of developing cardiovascular disease (CVD) due to the effects of stress and inflammation. This study investigates the correlation among IPV exposure, in-vivo CVD events, and inflammatory biomarkers as predictor indices(s) for CVD in female dental patients.

METHODS

Of 37 women enrolled in this study, 19 were African-American (AA) and 18 non-African-American (non-AA) and their ages ranged from 19 to 63 years. IPV-exposure and stress-induced in-vivo CVD events such as Chest Pain (CP) and Heart palpitations were recorded from all enrolled subjects. Cardiovascular events were obtained through surveys by patient self-report. Saliva specimens were obtained from all women and were analyzed for CVD biomarkers using multiplex-ELISA.

RESULTS

The prevalence of IPV was 51% (19/37) and statistically equivalent for AA and non-AA. The results show differences in experience of 1) CP (p < 0.01) and 2) heart palpitations (p < 0.02) when IPV + participants are compared with IPV- AA and non-AA cohorts. Of 10 CVD biomarkers analyzed, significant correlations between IPV+ and IPV- subjects were observed for biomarkers that include Interleukin-1β/sCD40L; TNFα/sCD40L; Myoglobin/IL-1β; CRP/sCD40L; CRP/IL-6; CRP/TNFα; TNFα/siCAM; CRP/MMP9; TNF-α/Adiponectin (p < 0.01).

DISCUSSION/IMPLICATIONS

Analysis of in vivo CVD status showed that significant race/health disparities exist in IPV + cohorts, as well as increased expression of inflammatory mediators, specifically CRP, IL-1β, IL-6, MMP9. Women who have experienced IPV may be a target cohort for primary prevention of CVD. The use of salivary biomarkers and our protocol may provide a less invasive method to help increase identification of victims at risk for IPV and CVD and potentially decrease other health injuries associated with IPV exposure.

Salivary peptidome profiling for diagnosis of severe early childhood caries

BACKGROUND

Severe early childhood caries (s-ECC), which has quite high prevalence among children, is a widespread problem with significant impacts among both developing and developed countries. At present, it is widely known that no early detective techniques and diagnostic tests could have high sensitivity and specificity when using for clinical screening of s-ECC. In this study, we had applied magnetic bead (MB)-based matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to screen distinctive candidate biomarkers of this disease, so as to establish protein profiles and diagnostic models of s-ECC.

METHODS

Firstly, we used the technique mentioned above to detect specifically expressed peptides in saliva samples from ten children with s-ECC, separately at the time point of before, 1 and 4 weeks after dental treatment. Then a diagnostic model for s-ECC was established with the K nearest-neighbour method, which was validated in another six children in the next stage of study. After that, linear ion trap-orbitrap-mass spectrometry (LTQ-Orbitrap-MS) was performed to identify which of the proteins in saliva might be the origination of these peptides.

RESULTS

We found that seven peptide peaks were significantly different when comparing the three time points, among them two were higher, while other five were lower in the pre-treatment s-ECC group compared with post-treatment. The sensitivity and specificity of the diagnostic model we built were both 83.3 %. Two of these peptides were identified to be segments of histatin-1, which was one important secretory protein in saliva.

CONCLUSIONS

Hereby we confirmed that MB-based MALDI-TOF MS is an effective method for screening distinctive peptides from the saliva of junior patients with s-ECC, and histatin-1 may probably be one important candidate biomarker of this common dental disease. These findings might have bright prospect in future in establishing new diagnostic methods for s-ECC.

Profiling of immunoglobulins in resting and mechanically stimulated saliva

BACKGROUND

Dysregulation of salivary immunoglobulins has been implicated in illnesses ranging from periodontal disease to HIV aids and malignant cancers. Despite these advances there is a lack of agreement among studies with regard to the salivary immunoglobulin levels in healthy controls.

METHODOLOGY

Resting and mechanically stimulated saliva samples and matching serum samples were collected from healthy individuals (n = 33; 40-55 years of age; gender: 23 female, 10 male). A matrix-matched AlphaLISA(®) assay was developed to determine the concentrations of IgG1 and IgG4 in serum and saliva samples.

CONCLUSION

Clear relationships were observed in the flow rate and concentration of each immunoglobulin in the two types of saliva. This study affirms the need to establish and standardize collection methods before salivary IgGs are used for diagnostic purposes.

DNA Methylation at the Novel CpG Sites in the Promoter of MED15/PCQAP Gene as a Biomarker for Head and Neck Cancers

Head and neck cancers (HNCs) represent a significant and ever-growing burden to the modern society, mainly due to the lack of early diagnostic methods. A significant number of HNCs is often associated with drinking, smoking, chewing beetle nut, and human papilloma virus (HPV) infections. We have analyzed DNA methylation patterns in tumor and normal tissue samples collected from head and neck squamous cell carcinoma (HNSCC) patients who were smokers. We have identified novel methylation sites in the promoter of the mediator complex subunit 15 (MED15/PCQAP) gene (encoing a co-factor important for regulation of transcription initiation for promoters of many genes), hypermethylated specifically in tumor cells. Two clusters of CpG dinucleotides methylated in tumors, but not in normal tissue from the same patients, were identified. These CpG methylation events in saliva samples were further validated in a separate cohort of HNSCC patients (who developed cancer due to smoking or HPV infections) and healthy controls using methylation-specific PCR (MSP). We used saliva as a biological medium because of its non-invasive nature, close proximity to the tumors, easiness and it is an economically viable option for large-scale screening studies. The methylation levels for the two identified CpG clusters were significantly different between the saliva samples collected from healthy controls and HNSCC individuals (Welch’s t-test returning P < 0.05 and Mann–Whitney test P < 0.01 for both). The developed MSP assays also provided a good discriminative ability with AUC values of 0.70 (P < 0.01) and 0.63 (P < 0.05). The identified novel CpG methylation sites may serve as potential non-invasive biomarkers for detecting HNSCC.

Magnetic bead-based salivary peptidome profiling for periodontal-orthodontic treatment

Background

Patients with periodontitis seek periodontal-orthodontic treatment to address certain functional and aesthetic problems. However, little is known of the effect of periodontitis on orthodontic treatment. Thus, we compared the differences in peptide mass fingerprints of orthodontic patients with and without periodontitis by MALDI-TOF MS using a magnetic bead-based peptidome analysis of saliva samples. In this way, we aimed to identify and explore a panel of differentially-expressed specific peptides.

Results

Saliva samples from 24 patients (eight orthodontic patients without periodontitis, eight with periodontitis and another eight with periodontitis but no orthodontic treatment) were analyzed, and peptide mass fingerprints were created by scanning MS signals using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) combined with magnetic beads. Nine mass peaks showed significant differences. Orthodontic patients in the group without periodontal disease showed higher mass peaks for seven peptides of the nine, whereas the mass peaks for the other two peptides were higher in the periodontal-orthodontic patients. Besides, these differentially-expressed peptides were sequenced.

Conclusions

The elucidated candidate biomarkers indicated interactions between periodontal condition and orthodontic treatment and their contributions to the changes of saliva protein profiles. Our results provide novel insight into the altered salivary protein profile during periodontal-orthodontic treatment, and may lead to the development of a therapeutic monitoring strategy for periodontics and orthodontics.

Tumor-suppressor Gene Promoter Hypermethylation in Saliva of Head and Neck Cancer Patients

Head and neck squamous cell carcinoma (HNSCC) accounts for a bulk of the oral and laryngeal cancers, the majority (70%) of which are associated with smoking and excessive drinking, major known risk factors for the development of HNSCC. In contrast to reports that suggest an inverse relationship between smoking and global DNA CpG methylation, hypermethylation of promoters of a number of genes was detected in saliva collected from patients with HNSCC. Using a sensitive methylation-specific polymerase chain reaction (MSP) assay to determine specific methylation events in the promoters of RASSF1A, DAPK1, and p16 genes, we demonstrate that we can detect tumor presence with an overall accuracy of 81% in the DNA isolated from saliva of patients with HNSCC (n = 143) when compared with the DNA isolated from the saliva of healthy nonsmoker controls (n = 31). The specificity for this MSP panel was 87% and the sensitivity was 80% (with a Fisher exact test P < .0001). In addition, the test panel performed extremely well in the detection of the early stages of HNSCCs, with a sensitivity of 94% and a specificity of 87%, and a high κ concordance value of 0.8, indicating an excellent overall agreement between the presence of HNSCC and a positive MSP panel result. In conclusion, we demonstrate that the promoter methylation of RASSF1A, DAPK1, and p16 MSP panel is useful in detecting hypermethylation events in a noninvasive manner in patients with HNSCC.

The impact of saliva collection and processing methods on CRP, IgE, and Myoglobin immunoassays

BACKGROUND

Owing to its ease of collection, saliva is potentially the sample of choice in diagnosis. Salivary biomolecules have provided a porthole in surveying a person's health and well-being. Our study aims were (1) to demonstrate the effects of pre-analytical steps, collection and pre-processing techniques on salivary protein detection and (2) to establish an indication of salivary reference intervals for 3 biomolecules of clinical interest.

METHODS

Saliva samples were collected from participants (n = 25, ages 20-35 years) using the following methods: no stimulation (resting/unstimulated), mechanical, and acid stimulation. The saliva was prepared for analysis by: unprocessed, post standard centrifugation in a container without any additives, and centrifugation using Centrifugal Filter Unit (Amicon® Ultra-0.5). AlphaLisa® assays were used to measure the levels of C-Reactive Protein (CRP), Immunoglobin (IgE) and myoglobin in saliva samples.

RESULTS

Saliva flow rates were lowest with the resting/drooling collection method. The lowest total protein concentration was with acid stimulation. Unstimulated and mechanically stimulated collections produced no effect on the CRP and IgE levels while myoglobin levels were highest with the unstimulated collection. Acid stimulation had a negative impact on the measured concentrations of IgE and myoglobin (except for CRP levels).

CONCLUSION

Mechanical stimulation was the most viable option for collecting saliva without affecting the levels of CRP and myoglobin. The processing methods had an adverse effect on the concentration of total protein as well as on CRP and IgE concentrations.