Potential uses of human salivary protein and peptide analysis in the diagnosis of disease. Arch Oral Biol 2012;7:1-9

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口腔病理科 On-Line KMU Student Bulletin

原文題目(出處)： Potential uses of human salivary protein and peptide analysis in the diagnosis of disease. Arch Oral Biol 2012;7:1-9

原文作者姓名： Kawas SAl, Rahim ZHA, Ferguson DB

通訊作者學校： Department of Oral & Craniofacial Health Sciences, College of Dentistry, University of Sharjah, Sharjah, United Arab Emirates

報告者姓名(組別)：李懿修 Intern K 組

報告日期： 2012/07/09

內文：

Introduction

 Mainly a mixture of the secretions from the three pairs of major salivary glands each secreting a characteristic type of saliva

 Contains gingival crevicular fluid, many microbial contaminants and from the desquamated cells of the oral epithelium

 Obtained by spitting into a test tube

 More sensitive and more specific markers for oral disease like squamous cell carcinoma

 Diagnostic tools to monitor both oral and systemic disease

 Advantage: Collection non-invasive, reducing patient discomfort, low cost, easy to collect

 Disadvantage: Requires centrifugation or filtration to remove precipitated mucins and cellular contaminants

 Complete analysis of salivary proteins and peptides with proteomic techniques and using salivary proteins and peptides as a biomarkers for systemic disease Analysis of the proteome of saliva

 Abundance of proteins with a wide range of functional properties included immune response and antimicrobial activity (lysozyme, lactoferrin)

 Salivary proteome-map out the total protein and peptide composition of the saliva

 Huq et al stated that over 1380 proteins have been detected in saliva but only around 100 of these are present in relatively high abundance

 Proline-rich, peptides, alpha-amylase, cystatins, histatins, mucins, secretory IgA and carbonic anhydrase well-known by protein analysis technique

 Techniques

 Separation of the salivary proteins by two-dimensional electrophoresis and detecting them with a suitable stain.

 Shotgun proteome analysis (enhanced resolutions)

 Combining surface chromatography with matrix-assisted laser desorption/ionisation time of flight mass spectrometry--rapid

 high performance liquid chromatography combined with mass spectrometry in the evaluation of the smallest salivary proteins and peptides

 Ionization methods such as electrospray ionization(ESI) and matri-assisted laser desorption ionization(MALDI)–can deplete proteins in order to improve identification of lower abundance proteins

 All these techniques together have extended proteome of whole saliva to comprise of more than 1050 proteins

 Well known--proline-rich peptides, alpha-amylase, cystatins, histatins,

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mucins, secretory IgA and carbonic anhydrase.

Proteome of normal human saliva

 Identified 914 proteins in parotid saliva and 917 proteins in submandibular/sublingual saliva from a total of 23 subjects (12 females and 11 males)

 174 of the 657 proteins found in plasma and 236 of the 467 proteins found in tears are also expressed in saliva.

Proteome of normal human saliva

 Major proteins reported: alpha-amylase, proline-rich proteins, cystatin, histatins and mucin

 Most involved in metabolic processes, complementand clotting cascades, cell adhesion and communication, cell cycle progression and regulation of the actin cytoskeleton

Problems of standardization

 Simply allowing saliva to accumulate in the mouth and then allowing it to dribble out, is subject to considerable variation as the patient tries

 Using wax stimulated saliva, or giving the patient a sterilised piece of soft plastic surgical cannula to chew

 Cellular and fluid components will be more in stimulated saliva

 A whole saliva free of bacterial and epithelial cell contamination is required.

 It is recommended that saliva samples should always be collected at the same time of day to reduce circadian variation

Concept of biomarkers

 A single molecular species which is present in samples from a subject with a particular disease or status, and is not present in other subjects.

 The range of variation which can be regarded as normal must be ascertained for a number of substances in a large population

 Degradation of proteins in whole saliva also contributes to variety in the proteins and peptides observed.

 cErb2 is found in the saliva of patients with mammary carcinoma but at very much lower concentrations in the saliva

Salivary proteomes in relation to oral diseases

 Dental caries susceptibility

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 Evaluation of periodontal disease

 Diagnosis of oral squamous cell carcinoma

 Salivary variation in other oral inflammatory diseases Dental caries susceptibility

 The two most common oral diseases are dental caries and periodontal disease

 Evaluate caries risk by measuring the amounts of selected oligosaccharides whose concentrations have shown a correlation with caries experience in young adults

 Changes in the saliva output during ageing correlated with greater risk of dental caries and may be indicators of caries risk

 Lower median values of alpha-defensins

 Statherin and cystatin S are the best predictors of occlusal caries in saliva Evaluation of periodontal disease

Enzyme immunosorbent assays test for 3 potential biomarkers:

1. Interleukin-1 beta as a marker of inflammation

2. Matrix metalloproteinase-8 as a marker of collagen breakdown

3. Osteoprotegerin as a marker for bone turnover compared salivary proteomes from patients with periodontitis

1. Blood proteins and immunoglobulins ↑ 2. Cystatins ↓

3. Alpha-amylase ↑

Biomarkers in saliva for three distinct phases of periodontal breakdown were identified

1. Interleukins 6 and 7

2. Matrix metalloproteinases 8 and 9 3. Osteoprotegerin and ICTP

Diagnosis of oral squamous cell carcinoma

 Heavy cigarette smokers:interleukin-8 and Thioredoxin(predisposing factor)

 CD44 ↑ distinguish cancer from benign tumours

 Three tumour markers:

1. Cytokeratin 19 fragment 2. Tissue polypeptide antigen 3. Cancer antigen 125

Salivary variation in other oral inflammatory diseases

 Oral lichen planus:

1. Urinary prokallikrein ↑

2. Expression of the palate, lung and nasal epithelium carcinoma associated protein ↓

Salivary proteomes in relation to systemic diseases

 Saliva has been used in the diagnosis of auto-immune deficiency syndrome (AIDS) and other viral infections such as hepatitis B and C.

 Detection of cErb2 in the saliva:

 higher levels of cErb2 in saliva with breast cancer

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 Theoretically other exocrine gland tumors might also raise salivary cErb2 levels in saliva

Practical issues

 Simple tests using whole saliva, unstimulated or stimulated, and they can be performed easily in standard clinical laboratories.

 It must be simple to use and preferably adapted for use in surgery or clinic Conclusions

 It is essential that a comprehensive database be established for the proteome of whole saliva collected and processed under standard conditions.

 It must show advantages over other tests, be sufficiently easy in use, and, preferably, able to give a rapid and accurate result in the clinical consultation. It should also be patient friendly.

 More research is required to validate the various discovered potential biomarkers for early disease detection that will lead to more effective treatment.

題號題目

1 What is the most common site for salivary gland tumor?

(A) Submandibular gland

(B) Sublingual gland

(C) Parotid gland

(D) Minor salivary gland

答案( C) 出處：Oral and Maxillo Facial Pathology p. 473

題號題目

2 What is the most common benign tumor?

(A) Pleomorphic adenoma

(B) Myoepithelioma

(C) Basal cell adenoma

(D) Warthin tumor

答案( A) 出處：Oral and Maxillofacial Pathology p. 473