SALIVA - ULTIMATE DIAGNOSTIC TOOL IN ORAL AND SYSTEMIC DISEASE

Saliva is secreted from the salivary glands and has multiple functions, as well as mouth cleansing and protection, antibacterial effects and digestion. 

Salivary diagnostics has influenced many researchers and has been verified as a very important tool within the identification of the many systemic conditions and prognosis of the illness.

With the fast advancement in salivaomics, spittle is well recognized as a pool of biological markers.
Serious investments were created, motivating scientists, governments, and industry to direct resources within the saliva diagnostics 

New technologies have tried their effectivity and disclosed an oversized variety of salivary biomarkers that are connected to many general and oral diseases. 

ADVANTAGES OF SALIVA AS A DIAGNOSTIC TOOL 

SALIVAOMICS

The term “salivaomics” was coined in 2008 to replicate the fast development of information regarding the various “omics” constituents of secretion.

A whole science of ‘omics’ has evolved since: genomics, Proteomics, Metabolomics, Metallomics, Transcriptomics, Urinomics, Salivaomics, Bacteriomics, Viromics, Pharmacogenomics etc.

Salivaomics  includes 5 diagnostic alphabets proteins, mRNAs, miRNAs, metabolic compounds, and microbes offers substantial blessings as a result of unwellness states is also in the course of detectable changes in one, however not all, dimensions

Salivary biomarkers 

• Salivary proteomics
• Proteomics is that the study of all the proteins during a given sample. Human salivary protein analysis is vital for understanding oral health and disease pathologic process.

• Salivary metabolomics
• Metabolomics is that the world assessment and validation of endogenous small-molecule metabolites among a biological system that has gained increasing quality and significance in life sciences.
• Intense research on diseases at the molecular level transformed clinical medication within the 21st century.

• Salivary transcriptome
• High-density oligonucleotide microarrays were accustomed profile secretion messenger RNA and discovered that there are 3,000 human mRNAs within the noncellular  saliva supernatant of healthy subjects.

Photo credit: www.semanticscholar.org

IN MY PREVIOUS BLOG I POSTED ABOUT RELATIONSHIP BETWEEN COVID-19 AND SALIVA AS A DIAGNOSTIC TOOL TO SEE THAT PLEASE CLICK THE BELOW LINK https://plasubash.blogspot.com/2020/06/saliva-supporter-or-attacker-during.html?m=1 

SYSTEMIC DISEASE 

DIABETES 

Common complications of diabetes involve multiple organs and embrace cardiovascular and periodontal diseases. little analysis has been done on salivary testing for the diagnosing of diabetes.

 
This is possibly as a result of easy-to-use pinprick tests are already on the market on the market to assess glucose blood levels. However, secretion proteomics supply a stimulating possibility for those that like a less invasive approach for screening. 

A recent study reported  the secretion proteomic profile of type 2 diabetes patients.
The Rao, Reddy and lu X found that fifty two proteins were otherwise expressed and better levels of some diabetes-related inflammatory biomarkers were determined in saliva of people with diabetes compared to controls. 

Other investigators have reported  that among a complete of 487 analysed proteins within the saliva, sixty five had higher levels in type-2 diabetes subjects compared to healthy people.

Therefore, protein identification in secretion may be a stimulating avenue to diagnose and monitor diabetes within the future. 

CARDIOVASCULAR DISEASE

Cardiovascular disease (CVD) includes atherosclerosis, coronary coronary heart disease, and myocardial infarction.

Atherosclerosis, the main etiological factor, is precipitated by means of the presence of inflammation, which leads to deposition of lipids inside the arterial walls and progressive narrowing of the arterial lumen. 

The studies performed through Kosaka et al.  display that the salivary tiers of IL-1β, IL-6, TNF-α, and prostaglandin E2 are expanded in atherosclerosis, suggesting that these cytokines could be capability biomarkers in the prognosis of atherosclerosis. 

Other research concluded the truth that different salivary markers may be C-reactive protein (CRP), myoglobin (MYO), creatine kinase myocardial band (CKMD), cardiac troponins (cTn), and myeloperoxidase. Acute myocardial infarction was predicted through a correlation of an ECG with the CRP ranges, proving 80% sensitivity and 100% specificity. 

Cardiac troponin (cTn), a biomarker for the detection of Acute myocardial infection  in saliva that is released in response to cardiac cellular necrosis.

Salivary cTn degrees had been proven to be a monitoring/diagnosis device as sensitive as their serum levels in patients laid low with Acute myocardial infection. 

In saliva, there have been also CK-MB and troponins identified, but their diagnostic ability changed into very low. 

Also, the tiers of α-2-HS-glycoprotein in saliva appear to lower in patients diagnosed with cardiovascular diseases, suggesting the reality that the peptidome can contribute to the early prognosis of these patients.

HIV

The existing tests for viral infections are supported secretion biomarkers, essentially on viral desoxyribonucleic acid and ribonucleic acid, antigens, and antibodies. 

Currently, many salivary tests are out there supported the proteomic analysis of the secretion and therefore the existing antibodies for hepatitis a, B, C viruses, HIV-1, rubella virus, mumps virus, and others. 

A new salivary test is employed by the san Raffaele Scientific Institute in Milano that's named OraQuick® 

Hepatitis C virus and represents a quick antibody test so as to notice simply the presence of the virus. 
Nefzi et al.conducted a study that showed the very fact that human CMV (HHV-6) seems to be a lot of simply known in secretion than in serum.

In 2012, OraSure Technologies, Inc. (Bethlehem, PA) proclaimed that the U.S. FDA had approved the over-the-counter OraQuick® In-Home HIV check to notice each HIV-1 and HIV-2 viruses with an oral swab. 

The results will be obtained within the comfort of the user's home. 

A swab is left in place for 2–5 min between the lower gingival and buccal mucosa to collect antibodies within the saliva. Then, the swab is shipped to a preset laboratory for Western blot analysis to confirm the diagnosing. 

The according specificity and sensitivity of this test are 99.98% and 93.0%, severally, compared with the laboratory analysis mistreatment blood samples. 

While the positive prognostic price (proportion of positive results that are actually positive) of OraQuick® In-Home HIV check of 98.7% is like blood-based specimens in populations with a high prevalence of HIV, it drops to 88.6% in low prevalence populations. 

The HIV (human immunodeficiency virus) is feasible through antibody-based screening assays. The diagnostic assay is an antibody assay that may be a Western blot test via blood or secretion or a enzyme chain reaction via blood. 

These specific tests have the aim at characteristic the p24 antigens and antibodies against HIV-1 and HIV-2. 

However, the detection of viral ribonucleic acid is difficult to be performed throughout salivary analysis because of the decreased  viral load

BREAST CANCER

Breast cancer is one in every of the foremost common cancers in females. 

ATP6AP1 is an ATPase that's expressed in normal tissues like the brain marrow, blood, nerves and skin, and it's additionally related to with many tumours like head and neck carcinomas, lung tumours, adrenal tumours and numerous other cancers. 

Nevertheless, its prevalence in breast cancer is that the greatest among these cancers. 
ATP6AP1 auto antibodies are spontaneously generated in patients and that they will be detected in early stages. 

Thus, it's indicated that ATP6AP1 will contribute to the first detection of carcinoma.

Zhang et al. found eight messenger RNA biomarkers and one protein biomarker that might be wont to sight breast cancer with an 83% sensitivity and 97% specificity. 

In another study, it had been found that the amount of vascular endothelial protein, epidermal growth factor (EGF) and carcinoembryonic antigen within the saliva were considerably inflated in patients with breast cancer.

The levels of CA15-3 and c-erB-2 were additionally found to be increased within the saliva, that has positive correlations with the blood serum of patients with carcinoma.

Based on these studies, potential salivary biomarkers will be applied to the first diagnosis of carcinoma.

salivary diagnostic biomarkers for cancer distant to the oral cavity. 

(accessed on 10 June 2020) 

ALZHEIMER'S DISEASE

Alzheimer’s disease (AD) is one in every of the foremost common neurovegetative disorders that occur to the aging population. 

 Until now, the precise biomarkers for this disease can be found within the cerebrospinal fluid through the amyloid b levels or exploitation structural and functional magnetic resonance imaging procedures that verified to be invasive and long. 

Further researches show that the existence of Ab and tau or a-Syn and DJ-1 in human saliva will be thought of proteins that are relating to Alzheimer’s disease and Parkinson’s disease, suggesting really the implication of spit and its potential within the diagnosing of neurodegenerative diseases. 

The study performed by Carro et al. investigates the potential of lactoferrin as a salivary biomarker for Alzheimer’s, supported the very fact that lactoferrin is an antimicrobial peptide that targets bacteria, fungi, protozoa, viruses, and yeasts.

The results of their study show that lactoferrin will be used as a biomarker for Alzheimer’s disease, once the result was compared to a standard test performed for the sure diagnosing of Alzheimer's disease , proving a really high correlation with valid cerebrospinal fluid biomarkers. 

Although a lot of studies are required, lactoferrin has proven its correlations and has the potential of being a solid biomarker which will facilitate the screening method of “apparently healthy” people that can suffer from a presymptomatic stage of the unwellness. 

Ahmadi-Motamayel et al.  conducted a recent study with the aim at evaluating acetylcholinesterase (AChE) and pseudocholinesterase (PChE) in whole saliva in patients with Alzheimer’s disease and in healthy subjects. 

Until now, several studies are performed specializing in the secretion biomarkers in Alzheimer’s unwellness and solely a number of concerning the salivary cholinesterase enzyme. 

The results of this study once the comparison of the secretion samples of the healthy subjects and people diagnosed with Alzheimer’s disease all over the very fact that AChE and PChE levels were raised in saliva samples of patients with Alzheimer’s disease. 

LUNG CANCER 

CT is being employed for routine screening for early lung cancer, with the disadvantage of a high false-positive rate. 

studies were performed by Xiao et al, sixteen potentially biomarkers are discovered that may expeditiously contribute to the salivary diagnosis. 

Salivary biomarkers have the potential to assist the first diagnosis without using CT.

Mutations known within the EGF receptor (EGFR) are the tumour-specific biomarkers for non-small cell lung carcinoma (NSCLC). a unique core technology called electrical field-induced unleash and measuring depends on a multiplexible electrochemical sensor that may find EGFR mutations in bodily fluids was shown to be effective, accurate, fast and efficient for the detection of EGFR mutations within the saliva of patients with NSCLC 

PARKINSON’S DISEASE

Parkinson’s disease is characterised pathologically by progressive degeneration of dopaminergic (DA) neurons within the substantia nigra pars compacta. 

The formation of a-synuclein- and ubiquitin-containing fibrillar inclusions (Lewy bodies and Lewy neurites) happens during this cell population likewise as variable changes in alternative neurotransmitter systems. 

The aim of the analysis initiated by Song et al. was to evaluate the levels and implications of salivary HO-1 in patients with upset Parkinson’s unwellness. 

The results showed that secretion HO-1 concentrations are considerably elevated in patients with upset pd versus nonneurological controls matched for sex. 

significantly, the check most effectively differentiated controls from Parkinson’s disease patients at the earliest motor stages of the disease and wasn't influenced by age, sex, and varied comorbidities. 

PROSTATE CANCER 

MiR-141 and miR-21 are 2 tumour biomarkers; the previous is considerably elevated in patients with advanced-stage prostate cancer, whereas the latter is overexpressed in early-stage prostate cancer. 

It has been incontestible that the expression of miR-21 and miR-141 within the saliva will be detected by nano-graphene oxide. 

This is expected to be a non- or minimally invasive approach to diagnose early-stage prostate cancer. 

ORAL DISEASE

CARIES 

Caries may be a results of demineralization of the tooth surface initiated by acid production of cariogenic bacterium.

This method will ultimately cause tooth loss. 

Many studies have incontestible the role of S. mutans in initiating tooth decay, whereas Lactobacilli have a role within the progression of carious lesions.

High secretion levels of each pathogens employing a commercially offered test (CRT bacteria®, Ivoclar-Vivadent inc., Amherst, U.S.A.) have shown a positive association with the presence of cavity in kids and adults. 

On the opposite hand, saliva is understood to play a protecting role against cavity since it contains many antibacterial agents, will automatically clear the pathogens and incorporates a buffering capability to decrease the acid concentration on tooth surfaces. Therefore, changes in amount and composition of saliva also can offer potential tools to discover and monitor dental caries. 

However, no single salivary test has shown consistent accuracy in detection dental caries. What has been steered is quite a mixture of famed risk factors to predict people at risk for cavity. However, none of the risk assessment programs projected up to now have shown consistent validity.

This can be explained by the involvement of multiple local and general risk factors within the dental caries development method 

SJOGREN'S SYNDROME

Sjögren’s syndrome (SS) may be a chronic general disease characterised by keratoconjunctivitis sicca and xerostomia. 

With additional development of SS, the secretion rate is reduced and therefore the salivary constituents amendment. 

There also are important changes within the protein and transcriptome in patients with SS. 

Thus, the amount of IL-4, IL-5 and protein clusters may facilitate to accurately predict the diagnoses for patients with SS.

Another analysis known nineteen genes (EPSTI1, IFI44, IFI44L, IFIT1, IFIT2, IFIT3, MX1, OAS1, SAMD9L, PSMB9, STAT1, HERC5, EV12B, CD53, SELL, HLA-DQA1, PTPRC, B2M and TAP2) that were closely concerning the pathologic process of SS, that was characterised by functions equivalent to induction of interferons, osmosis of lymphocytes and antigen presentation.

Hu et al. with success verified a panel of biomarkers that are elevated in patients with primary SS, as well as 3 messenger RNA biomarkers (myeloid cell nuclear differentiation antigen, guanylate binding protein 2 and low-affinity IIIb receptor for the Fc fragment of IgG) and 3 protein biomarkers (cathepsin D, α-enolase and β2-microglobulin).

These biomarkers from the protein and transcriptome may give a straightforward clinical tool for the diagnosing of primary SS within the early stages.

ORAL CANCER

The existence of gene mutations will usually be associated and used as biomarkers so as to diagnose carcinoma. 

In saliva, the tumor-specific desoxyribonucleic acid was positive in 100% of the patients diagnosed with carcinoma, and 47-70% of the patients with growths in alternative places of the body conjointly carry specific tumor deoxyribonucleic acid markers within the saliva. 

The p53 protein is liable for growth suppression, and it's created in cells as a response to multiple desoxyribonucleic acid damages. The inactivation of p53 throughout a mutation is one in every of the most causes of the event of malignancy. 

The increase in salivary levels of IL-8 and subcutaneous adipose tissue (SAT) incontestable  the best levels of sensitivity and specificity to discover OSCC. Another vital biomarker for OSCC is that the presence of human papillomavirus (HPV). 

A test is commercially obtainable in U.S. and North American nation for distinguishing people who are in danger of developing OSCC (OraRisk® HPV test, Oral DNA® Labs, Eden prairie, U.S.A.) on the premise that 60% of OSCC tumours are related to HPV-16. 

Salivary biomarkers represent, therefore, a powerful potential to isolate people who may develop carcinoma.

Studies have shown the very fact that p53 antibodies were detected within the saliva of patients diagnosed with oral squamous cell cancer. 

Cancer antigen 125 (CA 125) may be a tumor-associated antigen that was found in high levels within the saliva of the patients with oral, breast, and female internal reproductive organ cancer. 

Also, a very important facet is that the undeniable fact that secretion Hydrocortone levels were found to be considerably high within the saliva of patients diagnosed with OSCC. 

This association suggests that this hormone may be used as a marker for clinical staging. 

It may be Affirmed the very fact that each one the results prove that saliva has a very important charge of biomarkers that may be used with success in providing a screening and diagnosing of oral cancer.

PERIODONTAL DISEASE 

It is characterised by the destruction of the periodontal tissues similar to gingiva and bone that support the tooth. 

The activation of inflammatory mediators of host cells upon exposure to periodontal pathogens and their products primarily cause this condition.

Various secretion biomarkers are studied for the diagnosing and prognosis of periodontal diseases. 
These embody inflammatory mediators, enzymes, epithelial keratins, immunoglobulins, salivary ions and hormones.

Both whole secretion and gingival crevicular fluid (GCF) are utilized in periodontics to discover these potential biomarkers. 

More specifically, the presence of matrix metalloproteinase-8 (MMP-8, an enzyme answerable for tissue destruction) in GCF has been absolutely related to periodontal disease progression.

In 2010, an immunochromatographic chair-side dip-stick take a look at became commercially on the market to see the presence or absence of MMP-8 within the GCF with similar preciseness as typical laboratory assays.

Recently, it's been reported  that secretion soluble toll-like receptor-2 and interleukin-4 correlate absolutely with periodontal disease process.

It has been projected that not solely host-derived factors ought to be analysed within the secretion however additionally oral pathogens to be ready to predict periodontal disease, since it's a complex disease.

Investigators have found that higher secretion of levels of Porphyromonas gingivalis, Tannerella forsythia and Prevotella intermedia were found in people with progressive periodontal disease. 

Porphyromonas gingivalis could be a ‘red complex’ bacterium that's closely related to periodontal disease. 

Recently, some researchers developed an enzyme-linked immunosorbent assay-based P. gingivalis saliva kit to specifically discover this microorganism in saliva.

P. gingivalis secretion kit is fast and encompasses a sensitivity of 92% and a specificity of 96%. 

Therefore, the P. gingivalis saliva kit is anticipated to be a simple and time-efficient chair-side diagnostic tool for the detection of P. gingivalis.

A secretion take a look at will discover most of the periodontal pathogens (MyPerioPath®, OralDNA® Labs). 

The patient has got to rinse with saline for 30 s then spit during a collection tube. 

The samples are then sent by priority mail to the laboratory for microbiological analysis. 

That test has been approved for chair-side use within the u.  s. and North American country

Tobacco use is thought to be a serious risk issue for periodontal diseases. 

A recent study showed positive correlations between secretion superoxide dismutase levels and clinical symptoms similar to gingival index, pocket depth and clinical attachment loss in patients with chronic periodontal disease. 

The study additionally incontestable  the potential of secretion as a a lot of convenient and non-invasive way to diagnose patients with higher risks for precancerous lesions and conditions.

8 salivary phagocyte inflammatory protein-1α, matrix metalloproteinase-8, lymphokine (IL)-1β, IL-6, prostaglandin E2 and tumor necrosis issue (TNF)-α levels have shown potential for indicating gingivitis and periodontal disease 

Result of MyPerioPath® 

Photo credit: www.oraldna.com

CONCLUSION 

Patients visit their dentists more often than their physicians, it's been advised that salivary tests can pave the means for chair-side diagnosing of multiple oral and general diseases at the dental office

Systemic data networks of salivaomics and precise biomarkers of diseases will contribute to a stronger understanding of the correlations between oral health and general health, which can promote the appliance of preciseness medicine by facilitating the secernment of precise, painless and convenient targeted medical care.

Non-traditional, saliva-based diagnostic tests would need general acceptance by insurance firms, dentists and alternative health care professionals, that additional studies have to be compelled to demonstrate and establish their accuracy and value effectiveness. 

It is expected that the appearance of sensitive and specific secretion diagnostic tools and therefore the establishment of outlined tips can create salivary diagnostics a reality within the close to future.

REFERENCE

• Mohammad A. Javaid,a Ahad S. Ahmed,b Robert Durand,c and Simon D. Trand.(2016). Saliva as a diagnostic tool for oral and systemic disease. Available at URL:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4756071/
• Alexandra Roi , Laura C. Rusu  ,Ciprian I. Roi, Ruxandra E. Luca, Simina Boia,and Roxana I. Munteanu. (2019).A New Approach for the Diagnosis of Systemic and Oral Diseases Based on Salivary Biomolecules.  Available at URL:https://www.hindawi.com/journals/dm/2019/8761860/
• Manohar Bhat and Devikripa Bhat. (2019). Salivary Diagnostics in Oral Diseases. Available at URL:https://www.intechopen.com/books/saliva-and-salivary-diagnostics/salivary-diagnostics-in-oral-diseases
• Chen-Zi Zhang, Xing-Qun Cheng, Ji-Yao Li, Ping Zhang, Ping Yi, Xin Xu & Xue-Dong Zhou.(2019).Saliva in the diagnosis of diseases. Available at URL:https://www.nature.com/articles/ijos201638
• Suneetha Koneru, Rambabu Tanikonda. (2014).Salivaomics - A promising future in early diagnosis of dental diseases. Avaliable at URL:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3955304/
• Sripad, S. Salivaomics in systemic disease: an evolving science- an interesting prospect for ‘lab-on-chip’ diagnostics in coronary artery and other systemic diseases. Indian J Thorac Cardiovasc Surg 34, 95–97 (2018). https://doi.org/10.1007/s12055-017-0597-8.