Study of Salivary Enzymes in Oral Lesions

INTRODUCTION

Tobacco consumption leads to staining of teeth and dental plagues and is a significant risk factor for oral diseases. Though the bases of benign and malignant oral lesions are multifactorial, it definitely reflects metabolic changes in the body due to cell death and cell injury. Changes in the constituents of saliva are associated with certain diseases and therefore helpful for diagnosis.^1,2 Level of enzymes, such as, peroxidase, lactate dehydrogenase, creatinine kinases, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) is increased in certain diseases. In oral cavity diseases, these enzyme levels are increased in saliva. It has been studied that salivary levels of AST and ALT were increased in periodontitis, and after treatment, these enzyme levels get decreased.³ According to Dewan et al., AST level in GCF could be a potential biochemical marker for periodontal disease progression.⁴ The AST and ALT values in the saliva were 138 to 229% of normal value in all head and neck cancers.⁵ Thus, in all oral diseases, AST and ALT enzymes in the saliva were increased. The values of these enzymes decrease or come to normal levels at the end of treatment. In 92% of head and neck cancer cases, the AST and ALT were normal or near-normal after radiotherapy. Therefore, salivary enzymes, such as, AST and ALT can be used as biochemical tumor markers in malignant conditions. Rai et al. showed that salivary AST, ALT, and LDH levels can be used as markers of oral diseases.⁶ Oral malignancy can be detected early with the help of salivary biomarkers.⁷ It may also be possible to detect early oral malignancy with the help of salivary levels of cytokines.⁸

MATERIALS AND METHODS

A retrospective study of 150 patients with benign oral lesion was included in this study. Tobacco addict patients with benign and malignant oral lesions among 15 years and 60 years of the age group who attended ENT OPD in medical college hospitals in Mumbai from January 2013 to June 2014 were selected. In the present study, tobacco addict patients were selected on personal interview. Daily tobacco consumption in any one or more form of tobacco, tobacco with lime, tobacco consumption in the pan (quit), tobacco mishari application on teeth, tobacco smoking in the form of bidis and cigarettes, ghutka, mawa, jerda, tobacco used as snuff, etc., for more than two years duration was included in tobacco addiction. The selection of patients was done at random. Patients with salivary gland tumors and diseases and patients below 15 years. The age was excluded from the study. Patients with diabetes mellitus and known hormonal disorders were also excluded from the study. Healthy persons without tobacco addiction and without any oral lesion whose age and sex were matched were included in the control group. Written informed consent was taken from the participants.

The study was approved by the Ethics Committee of Institute. Collection of saliva samples (5 mL) was done using the “draining method” from the mouth of the patient. Saliva was collected in sterile containers, and the saliva samples were centrifuged at 10,000 rpm for 10 minutes. AST and ALT in the collected samples were determined spectrophotometrically.

Statistical analysis was done to compare the enzymatic activity among the tobacco chewers with the benign and malignant oral regions and healthy non-tobacco consumers.

RESULTS

Table 1 shows AST and ALT among healthy subjects, in control, benign, and malignant oral conditions. The results showed that AST in patients with benign and malignant oral conditions was higher than the control group, and it is statistically not significant. Salivary enzymes, such as, ALT in patients with benign conditions were slightly lower and in malignant oral conditions were higher than the control group. But the results were statistically not significant.

The obtained results have shown that AST and ALT in the saliva of the patients with benign and malignant conditions were not significantly increased as compared with the control group.

DISCUSSION

There are salivary glands present in the human body. According to the size of glands, these glands are divided into two groups, major and minor salivary glands. Parotid glands, submandibular glands, and sublingual glands are three major salivary glands. Secretions of these glands contain water, electrolytes, sodium, potassium, calcium, chloride, magnesium, bicarbonate, and phosphate. It also contains proteins, such as, enzymes, mucosal glycoproteins, albumin, some polypeptides, oligopeptides, and immunoglobulin. Glucose, urea, and ammonia are also seen in salivary gland secretions. Salivary enzymes are proteins. These are α-amylase, albumin, cystins, hystatins, secretory IgA, and lactoferrin.⁹ Some proteinous and non-proteinous substances require advanced instruments for their detection. CA125, haptoglobin, profilin-1, and transferrin are salivary markers for breast carcinomas.^10,11 Salivary marker for lung cancer is S100 calcium-binding protein A9.¹² Salivary annexin A1, carbonic anhydrase VI, S100 calcium-binding protein, and lipocalin are helpful for the detection of both breast and lung cancers.¹³ Cox multivariate analysis showed that for RFS, Stat3 and c-myc, and for OS, Stat3, Bcl-2, and p53 were helpful for the prognosis of tongue carcinoma. Buccal mucosa and tongue carcinoma have different salivary markers.¹³

A study done by Girja et al. in 2002 has proven major changes in the salivary biochemical composition of leukoplakia (premalignant) and oral malignancy.¹⁴ These changes may be due to tobacco uses or disease process. Brailo et al.¹⁵ also studied changes in the salivary IL-6 and tumor necrosis factor alpha (TNF-α) in benign and malignant conditions.

In the present study, there was a rise in salivary AST in a study group, which was not significant. There was no significant change in salivary AST between benign and malignant conditions and control group. Research is going on salivary biomarkers, but these salivary biomarkers lack sensitivity and specificity and cannot be applied.

CONCLUSION

In the present study, there was a rise in salivary AST in a study group, which was not significant. There was no significant change in salivary AST between benign and malignant conditions and control group.

CLINICAL SIGNIFICANCE

Research is going on salivary biomarkers, but these salivary biomarkers lack sensitivity and specificity and cannot be applied.

ACKNOWLEDGMENT

The authors are thankful to Dr VW Patil, Professor and Head, Department of Biochemistry, GGMC and Sir JJ Group of Hospitals, Mumbai, India, for his encouragement to prepare the study material.

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