New insights into salivary lactate dehydrogenase of human subjects

Compatibility of salivary lactate dehydrogenase level using a test kit with the community periodontal index in Japanese adults

The purpose of this study was to investigate the association between salivary lactate dehydrogenase (LD) levels, assessed using a test kit, and the community periodontal index (CPI) and to determine the feasibility and reliability of the test kit for screening periodontal disease in adults. The study included 205 patients (58.5% female, median and 25-75 percentiles of age 55.0, 46.0-66.0 years) who visited two university hospitals and one university clinic in Japan. Resting saliva sample was collected from each participant, and LD level was evaluated in real time using a kit featuring an integer scale ranging from 1 to 10. Individual pocket scores were categorized as follows: score = 0 (≤ 3 mm), score = 1 (4-5 mm), and score = 2 (≥ 6 mm) and gingival bleeding scores were categorized as follows: score = 0 (absence of condition) and score = 1 (presence of condition). Notably, 120 participants (58.5%) exhibited a pocket score = 1 or 2, and 123 participants (60.0%) exhibited a gingival bleeding score = 1. The optimal cutoff values for salivary LD level to distinguish pocket scores = 1 or 2 from 0 and score = 2 from 0 or 1 were 4.0 and 5.0, respectively, with a sensitivity and specificity of ≥ 0.65. The median salivary LD level for a gingival score = 1 was significantly higher than that for gingival score = 0, and the optimal cutoff value for the salivary LD level was 4.0, with a sensitivity and specificity of ≥ 0.62. Our results suggested that a salivary LD level ≥ 4.0 in adults may suggest the presence of periodontal disease, thereby emphasizing the kit`s utility as a screening tool.

Estimation of Periodontal Inflamed Surface Area by Salivary Lactate Dehydrogenase Level Using a Test Kit

Background: Salivary lactate dehydrogenase (LD) levels are a feasible and useful parameter for screening periodontal diseases. The periodontal inflamed surface area (PISA) is useful to clinically assess periodontal diseases. However, PISA is difficult to calculate and PISA-compatible screening kits are required. We aimed to investigate the association between salivary LD levels, using a test kit, and PISA and PISA-Japanese and determine the feasibility and reliability of the salivary LD test kit for evaluation of periodontal status. Methods: This study included 110 patients (66.4% female, median and 25-75 percentiles of age were 66.5 and 53.0-75.0 years, respectively) who visited the Dental University Clinic in Japan. Resting saliva samples were collected from each participant and LD levels were evaluated in real time using a kit featuring an integer scale ranging from 1 to 10. PISA and PISA-Japanese were calculated using periodontal parameters. Results: The median salivary LD level was 4.0. The medians of PISA and PISA-Japanese were 46.9 and 61.0, respectively. Salivary LD levels were positively correlated with the bleeding on probing rate (r = 0.626, p < 0.001), PISA (r = 0.560, p < 0.001), and PISA-Japanese (r = 0.581, p < 0.001). Conclusions: Our results suggest that salivary LD levels assessed using the salivary LD kit showed a significantly positive correlation with PISA and PISA-Japanese. In addition, we developed the PISA estimation formula using salivary LD levels measured with a test kit, sex, and age.

Evaluation of Serum and Salivary Lactate Dehydrogenase Levels in Patients with Oral Potentially Malignant Conditions/Lesions: A Clinical and Biochemical Study

Background

Oral cancer encompasses all malignancies that originate in the oral tissues and remains a major public health problem throughout the world as an important case of poor health and illness. Head and neck cancer accounts for 9.8% of the estimated 6,44,600 incidental cancer cases in India. Oral Squamous Cell Carcinoma (SCC) is a serious and developing concern globally, accounting for more than 90% of malignant cancers of the oral cavity. Salivary diagnostics have been demonstrated to have potential in the detection and screening of oral pre-cancer and cancer in a variety of research settings. The continual and close contact between saliva and the mucosa, where cancer develops, is the foundation of this diagnostic capability.

Materials and Methods

This research utilized spectrophotometry to quantify Lactate Dehydrogenase levels in serum and saliva of 30 healthy people which consisted the control group and 31 Oral Potentially Malignant people which constituted the study group.

Results

On estimation and comparison, the mean Lactate Dehydrogenase levels in serum (397.4968+71.6392 IU/L) and saliva (675.4935+139.3352 IU/L) among patients with Oral Potentially malignant lesions/conditions were higher than the mean Lactate Dehydrogenase levels in serum (390.8667+71.0953 IU/L) and saliva (201.3700+89.1439 IU/L) among controls.

Conclusion

Higher serum and salivary LDH levels in Oral Potentially malignant lesions/conditions than in control groups signifies the importance of assessing salivary LDH levels, in the prognosis of the same. Further prospective longitudinal studies are required to assess the salivary LDH levels among the patients with malignant transformation of Oral Potentially malignant lesions/conditions to oral cancers.

Characterization of genetic and molecular tools for studying the endogenous expression of Lactate dehydrogenase in Drosophila melanogaster

Drosophila melanogaster larval development relies on a specialized metabolic state that utilizes carbohydrates and other dietary nutrients to promote rapid growth. One unique feature of the larval metabolic program is that Lactate Dehydrogenase (Ldh) activity is highly elevated during this growth phase when compared to other stages of the fly life cycle, indicating that Ldh serves a key role in promoting juvenile development. Previous studies of larval Ldh activity have largely focused on the function of this enzyme at the whole animal level, however, Ldh expression varies significantly among larval tissues, raising the question of how this enzyme promotes tissue-specific growth programs. Here we characterize two transgene reporters and an antibody that can be used to study Ldh expression in vivo. We find that all three tools produce similar Ldh expression patterns. Moreover, these reagents demonstrate that the larval Ldh expression pattern is complex, suggesting the purpose of this enzyme varies across cell types. Overall, our studies validate a series of genetic and molecular reagents that can be used to study glycolytic metabolism in the fly.

Lactate Dehydrogenase as a Biomarker in Oral Submucous Fibrosis: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis was planned with the objective of evaluating the level of Lactate Dehydrogenase (LDH) in oral submucous fibrosis patients and in controls and comparing them. For this meta-analysis, we searched Google Scholar, PubMed, Scopus, and Directory of Open Access Journals (DOAJ) databases using a search methodology that included combinations of MeSH terms and keywords and included cross-sectional studies to evaluate the levels of LDH in patients with Oral Submucous Fibrosis (OSMF), Oral Squamous Cell Carcinoma (OSCC) and compared it with the controls. The total number of records identified through database searching was 4161 (n). Analysis of the quality of the studies was done using the National Heart, Lungs and Blood Institute (NHLBI) tool for case-control studies. Twelve case-control studies which matched the inclusion criteria were included after the literature search. The meta-analysis was carried out using R Studio (version 4.1.3, 2022; The R Foundation for Statistical Computing, Vienna, Austria). The pooled estimate that has been calculated from the salivary LDH course for OSMF was 15.35% and from the serum LDH course for OSMF was 6.82%. There was a visual observation of the funnel's plot asymmetry suggesting publication bias. After adjusting the publication bias, the t2 values for salivary and serum LDH were 41% and 14.71%, respectively, which was less than 50%, indicating that the meta-analysis was statistically significant. The evaluation of salivary and serum LDH can be a useful method for early diagnosis of OSMF as well as OSCC. To infer that individuals may have OPMD or OSCC, specific values for salivary and serum LDH must be found in further investigations.

Characterization of genetic and molecular tools for studying the endogenous expression of Lactate dehydrogenase in Drosophila melanogaster

Drosophila melanogaster larval development relies on a specialized metabolic state that utilizes carbohydrates and other dietary nutrients to promote rapid growth. One unique feature of the larval metabolic program is that Lactate Dehydrogenase (Ldh) activity is highly elevated during this growth phase when compared to other stages of the fly life cycle, indicating that Ldh serves a key role in promoting juvenile development. Previous studies of larval Ldh activity have largely focused on the function of this enzyme at the whole animal level, however, Ldh expression varies significantly among larval tissues, raising the question of how this enzyme promotes tissue-specific growth programs. Here we characterize two transgene reporters and an antibody that can be used to study Ldh expression in vivo . We find that all three tools produce similar Ldh expression patterns. Moreover, these reagents demonstrate that the larval Ldh expression pattern is complex, suggesting the purpose of this enzyme varies across cell types. Overall, our studies validate a series of genetic and molecular reagents that can be used to study glycolytic metabolism in the fly.

Is there any correlation between muscle fatigue and serum lactate dehydrogenase levels in prediabetic individuals?

Aim: Lactate dehydrogenase (LDH) is an enzyme that acts as a catalyst in the conversion of lactate to pyruvate which is abundantly found in liver, kidney, heart and muscles. Previous studies have all shown a strong positive correlation between muscle fatigue and increased serum LDH levels with type 2 diabetes mellitus but no study has actually assessed the same for prediabetes. The basic objective of this study, thus, is to find out the correlation between muscle fatigue and serum LDH levels in prediabetic individuals. Methods: A cross-sectional study was conducted in adults between 24–60 years old who were classified as prediabetic individuals as per norms established by American Diabetes Association. A total of 100 prediabetic individuals were selected for the study. Fatigability was calculated as a function of work done by the pleximeter finger of the dominant hand using Mosso’s ergograph. The study was conducted at Rajarshi Dashrath Autonomous State Medical College, Ayodhya. Results: Out of 100 prediabetic participants, 50% were males with a mean age of 44.14 ± 10.91 years and remaining 50% were females with a mean age of 41.12 ± 11.5 years. Overall, the average work done by the participants was 2.9 ± 1.2 weight lifted•total distance moved (kg•m) with an average serum LDH level of 323.84 ± 26.82 unit/litre (U/L). Conclusions: This study aimed at assessing the correlation between muscle fatigue and serum LDH levels in prediabetic individuals so that further work can be initiated to improve the quality of life in prediabetics that maybe drastically hampered due to easy fatigability in prediabetic individuals.

Salivary Lactate Dehydrogenase, C-Reactive Protein, and Cancer Antigen 125 Levels in Patients with Oral Lichen Planus and Oral Squamous Cell Carcinoma

Background: Oral squamous cell carcinoma (OSCC) is the most common malignancy of the oral cavity and oral lichen planus (OLP) is considered a premalignant disease. Objectives: This study aims at comparing the salivary levels of lactate dehydrogenase (LDH), C-reactive protein (CRP), and cancer antigen 125 (CA125) among cases with OSCC, OLP, and healthy persons. Methods: In this case-control study, salivary markers were evaluated in 55 cases (15 patients with OSCC, 20 patients with OLP, and 20 healthy persons); non-stimulated saliva samples were collected from the patients and saliva markers were measured by the enzyme-linked immunosorbent assay (ELISA) method. The data were analyzed, using SPSS 21 software and ANOVA test and P < 0.05 was regarded as significant. Results: Salivary LDH and CA125 levels were significantly higher in OSCC and OLP patients compared to the control group (P < 0.05). Salivary CRP levels were significantly higher in OSCC patients compared to OLP patients (P < 0.05). Besides, salivary CRP levels were higher in OLP subjects than in the control group, but the difference was not significant (P = 0.56). Conclusions: The identification of the salivary LDH, CA125, and CRP may provide a suitable non-invasive predictive tool for malignant changes. However, its use in clinical practice needs further research.

Identification of potential candidate genes for lip and oral cavity cancer using network analysis

Lip and oral cavity cancer, which can occur in any part of the mouth, is the 11th most common type of cancer worldwide. The major obstacles to patients' survival are the poor prognosis, lack of specific biomarkers, and expensive therapeutic alternatives. This study aimed to identify the main genes and pathways associated with lip and oral cavity carcinoma using network analysis and to analyze its molecular mechanism and prognostic significance further. In this study, 472 genes causing lip and oral cavity carcinoma were retrieved from the DisGeNET database. A protein-protein interaction network was developed for network analysis using the STRING database. VEGFA, IL6, MAPK3, INS, TNF, MAPK8, MMP9, CXCL8, EGF, and PTGS2 were recognized as network hub genes using the maximum clique centrality algorithm available in cytoHubba, and nine potential drug candidates (ranibizumab, siltuximab, sulindac, pomalidomide, dexrazoxane, endostatin, pamidronic acid, cetuximab, and apricoxib) for lip and oral cavity cancer were identified from the DGIdb database. Gene enrichment analysis was also performed to identify the gene ontology categorization of cellular components, biological processes, molecular functions, and biological pathways. The genes identified in this study could furnish a new understanding of the underlying molecular mechanisms of carcinogenesis and provide more reliable biomarkers for early diagnosis, prognostication, and treatment of lip and oral cavity cancer.

Assessment of Lactate Dehydrogenase Levels Among Diabetic Patients Treated in the Outpatient Clinics at King Hussein Medical Center, Royal Medical Services, Jordan

Introduction

Diabetes is a chronic disease and usually is associated with inflammatory conditions. Although assessment of inflammatory markers such lactate dehydrogenase (LDH) is not likely to be conducted in routine practice, it can help in monitoring disease progress.

Aim

The main objectives of the present study are to assess the levels of LDH among diabetic patients treated in the outpatient clinics at King Hussein Medical Center, and to investigate the relationships between the levels of LDH and other variables such as age, gender, BMI, and glucose levels.

Methods

A retrospective study was conducted to collect data from files of diabetic patients. A total of 62 files were selected. Files of diabetic patients were included if complete information including LDH are included. An excel sheet was used to enter the raw data for all patients. The data were analyzed using SPSS version 20. Data were presented as means, standard deviations, frequencies and percentages. The relationships between variables were computed using T test, and Chi-square. The significance will be considered at p ≤ 0.05.

Results

The mean age was 75±12 years. About 53% of participants were males. The mean of BMI was 31.47±20.90 kg/m2. The mean glucose level was 239±85 mg/dl. The mean level of LDH was 328.34±78 U/L. There was a significant association between the level of LDH and study variables. Gender had no significant impacts on the levels of LH and other study variables.

Conclusion

Determination of the level of LDH helps in assessment of progression of diabetes and it is recommended to be performed clinically in routine practice.

Evaluation of Tissue and Serum Expression Levels of Lactate Dehydrogenase Isoenzymes in Patients with Head and Neck Squamous Cell Carcinoma

BACKGROUND

Head and Neck Squamous Cell Carcinoma (HNSCC) is a common malignancy that is associated with high morbidity and mortality all over the world. We explored the role of mRNA expression of both subunits of LDH in the early diagnosis of HNSCC.

MATERIALS AND METHODS

This was a case-control study on 62 healthy individuals and 62 patients with HNSCC. The expression of LDH in tumors and healthy tissue margins, and in the serum of both HNSCC patients and healthy individuals was evaluated using a quantitative real-time PCR method. Analysis of LDH-A and LDH-B expression and sensitivity-specificity analysis were carried out using SPSS software.

RESULTS

mRNA expression levels of LDH-A (4.18±1.29) and LDH-B (2.85±1.07) isoenzymes in tumor tissues were significantly higher than the expressions in the corresponding healthy tissue margins (1.85±0.56 and 1.61±0.56 for LDH-A and LDH-B, respectively). A comparison of LDH-B expression between histological grade I tumor tissue (2.74±0.19) and marginal tissue (1.62±0.90) showed a significant difference (P=0.016). Patients with a positive history of alcohol consumption and cigarette smoking had significantly higher mRNA expression of LDH-A (P=0.024) and LDH-B (P=0.03) in the marginal tissue and blood, respectively. The highest sensitivity and specificity values pertained to the mRNA expression of LDH-A (90.9%) and LDH-B (85.5%) in the blood.

CONCLUSION

This is the first study reporting LDH gene expression as a biomarker in blood and tumoral tissue of HNSCC patients. Given the highest sensitivity and specificity values for LDH-A and LDH-B in blood, we recommend the simultaneous evaluation of both LDH isoenzymes in blood samples as a potential diagnostic method.

Metabolic Profiles of Whole, Parotid and Submandibular/Sublingual Saliva

The detection of salivary molecules associated with pathological and physiological alterations has encouraged the search of novel and non-invasive diagnostic biomarkers for oral health evaluation. While genomic, transcriptomic, and proteomic profiles of human saliva have been reported, its metabolic composition is a topic of research: metabolites in submandibular/sublingual saliva have never been analyzed systematically. In this study, samples of whole, parotid, and submandibular/sublingual saliva from 20 healthy donors, without dental or periodontal diseases, were examined by nuclear magnetic resonance. We identified metabolites which are differently distributed within the three saliva subtypes (54 in whole, 49 in parotid, and 36 in submandibular/sublingual saliva). Principal component analysis revealed a distinct cluster for whole saliva and a partial overlap for parotid and submandibular/sublingual metabolites. We found exclusive metabolites for each subtype: 2-hydroxy-3-methylvalerate, 3-methyl-glutarate, 3-phenylpropionate, 4-hydroxyphenylacetate, 4-hydroxyphenyllactate, galactose, and isocaproate in whole saliva; caprylate and glycolate in submandibular/sublingual saliva; arginine in parotid saliva. Salivary metabolites were classified into standard and non-proteinogenic amino acids and amines; simple carbohydrates; organic acids; bacterial-derived metabolites. The identification of a salivary gland-specific metabolic composition in healthy people provides the basis to invigorate the search for salivary biomarkers associated with oral and systemic diseases.

Assessment of lactate dehydrogenase enzyme levels in saliva and serum of oral submucous fibrosis and leukoplakia patients

Background:

Pathology involving the oral epithelium may alter the level of salivary concentration of LDH. Thus its estimation can be used as a non invasive screening tool for the early detection of OPMDs and also to predict its malignant transformation especially in high risk population.

Aims and Objectives:

To evaluate the salivary and serum levels of lactate dehydrogenase (LDH) in patients having of oral submucous fibrosis (OSMF) and leukoplakia and compare it with healthy individuals.

Materials and Methods:

A total of 120 subjects were selected and divided into three groups comprising clinically diagnosed cases of OSMF and leukoplakia and healthy subjects as controls. Unstimulated whole saliva and blood samples were collected under aseptic conditions for biochemical estimation of LDH by Semiautomatic Analyzer using LDH kit utilizing enzymatic UV-Kinetic method. The values obtained were statistically analyzed using the SPSS software version 20.0. P-value < 0.05 was considered significant.

Results:

The mean salivary LDH level in Group I (OSMF) was 631.67 + 7.67, Group II (Leukoplakia) was 492.28 + 16.17 and Group III (Healthy Control) was 140.62 + 8.87. There was a statistically significant difference between the Serum and salivary LDH levels among the various groups of study population. A positive correlation between salivary LDH and serum LDH level was seen and the regression equation for OSMF and leukoplakia was computed.

Conclusion:

A significant difference was found between mean salivary LDH Levels and serum LDH levels in patients with leukoplakia, OSMF and health controls. A positive correlation was also established between salivary and serum LDH levels in patients with OSMF and leukoplakia patients making saliva a potent non invasive tool for early prediction and detection of PMOD and its malignant transformation.

Evaluation of salivary biomarkers of periodontitis among smokers and nonsmokers: A novel study

Background:

The analysis of salivary enzymes contributes to the clarification of pathogenesis and improvement in the diagnosis of periodontal disease. The present study aimed to examine the prospective association between smoking and periodontal disease progression and the effects of smoking on the following salivary biomarkers related to periodontitis: Alkaline phosphatase (ALP), acid phosphatase (ACP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), creatinine (CRE), blood urea nitrogen (BUN), urea (UA), free-hemoglobin (f-Hb), and neopterin.

Materials and Methods:

A total of 64 male patients aged 21–60 years were recruited and grouped as Group 1: 16 healthy nonsmokers, who had never smoked. Group 2: 16 smokers with gingivitis. Group 3: 16 smokers with moderate periodontitis. Group 4: 16 smokers with severe periodontitis. Stimulated saliva was collected for at least 5 min and clinical measurements; salivary biomarkers were assessed in automated analyzer.

Results:

Data showed significant correlation among salivary ACP, AST, LDH, CRE, BUN, UA, and f-Hb and neopterin levels showed higher in group 4 compared with other groups.

Conclusion:

This study indicated that smoking has several detrimental effects on periodontal tissues. A higher level of salivary biomarkers was seen in smokers with severe periodontitis. Hence, these biomarkers are helpful in future for the earlier detection of periodontal diseases progression and can also be used as potential salivary biomarkers for assessing smoking status and severity in chronic periodontitis.

Comparison of Salivary and Serum Alkaline Phosphates Level and Lactate Dehydrogenase Levels in Patients with Tobacco Related Oral Lesions with Healthy Subjects - A Step Towards Early Diagnosis

AIM

To evaluate and compare salivary and serum levels of Alkaline Phosphates and Lactate Dehydrogenase in patients without the habit of tobacco, in patients with the habit of tobacco, in patients with benign oral lesions and in patients with oral premalignant lesions and oral malignant lesions.

MATERIAL AND METHODOLOGY

This study was comprised of 500 subjects, Group I: 100 healthy individuals without the habit of tobacco usage formed the control group. Group II: 100 patients with the habit of tobacco/ smoking consumption without any oral lesion. Group III: 100 patients with benign oral lesions. Group IV: 100 patients having the history of tobacco consumption and having apparent precancerous lesions like leukoplakia, erythroplakia. Group V:100  patients having frank oral cancer. The grade of dysplasia in these patients was statically correlated with the levels of serum and salivary ALP and LDH.

RESULTS

This study revealed that there was high expression of both serum and salivary ALP and LDH  in group IV and Group V as compared with the other groups and mean difference showed a statistically significant p value of less than 0.01. This study revealed that the in group V, the highest level of serum and salivary ALP was found in those patients who were reported with poorly differentiated oral cancer.

CONCLUSION

Both Alkaline phosphates and Lactate dehydrogenase could be considered a sensitive markers for the detection of dysplasia with already existing precancancerous and cancerous lesions.

Age and gender characteristics of the biochemical composition of saliva: Correlations with the composition of blood plasma

Background

Recently, the attention of researchers to the study of the properties of human saliva, as a material with unique properties and diagnostic capabilities, has increased.

Research objective

to study the connection of the biochemical composition of saliva and blood plasma in the norm, depending on gender and age.

Methods

107 volunteers took part in the study, including 46 female (37.2 ± 3.9 years old) and 61 male (36.1 ± 2.8 years old). In all samples of saliva and blood plasma, 16 biochemical parameters were determined, including mineral and protein composition, enzyme activity. Non-parametric statistical methods were used to process the data.

Results

It has been shown that it is difficult to establish an unambiguous relation between biochemical parameters of saliva and blood plasma. The calculation of the Spearman correlation coefficients showed that only 7 of the 16 parameters demonstrate the presence of a weak correlation between the content in saliva and plasma.

Conclusion

In general, the determination of the composition of saliva may have an independent diagnostic value; in this case, drawing a parallel with the composition of serum and blood plasma is not advisable. Nevertheless, the use of saliva in clinical laboratory diagnostics is associated with the need to establish criteria for the norm and pathology for each biochemical parameter.

Changes of salivary biomarkers under different storage conditions: effects of temperature and length of storage

Introduction

In this report, we aimed to examine the stability of various analytes in saliva under different storage conditions.

Materials and methods

Alpha-amylase (AMY), cholinesterase (CHE), lipase (Lip), total esterase (TEA), creatine kinase (CK), aspartate aminotransferase (AST), lactate dehydrogenase (LD), lactate (Lact), adenosine deaminase (ADA), Trolox equivalent antioxidant capacity (TEAC), ferric reducing ability (FRAS), cupric reducing antioxidant capacity (CUPRAC), uric acid (UA), catalase (CAT), advanced oxidation protein products (AOPP) and hydrogen peroxide (H₂O₂) were colorimetrically measured in saliva obtained by passive drool from 12 healthy voluntary donors at baseline and after 3, 6, 24, 72 hours, 7 and 14 days at room temperature (RT) and 4 ºC, and after 14 days, 1, 3 and 6 months at – 20 ºC and – 80 ºC.

Results

At RT, changes appeared at 6 hours for TEA and H₂O₂; 24 hours for Lip, CK, ADA and CUPRAC; and 72 hours for LD, Lact, FRAS, UA and AOPP. At 4 ºC changes were observed after 6 hours for TEA and H₂O₂; 24 hours for Lip and CUPRAC; 72 hours for CK; and 7 days for LD, FRAS and UA. At – 20 ºC changes appeared after 14 days for AST, Lip, CK and LD; and 3 months for TEA and H₂O₂. At – 80 ºC observed changes were after 3 months for TEA and H₂O₂.

Conclusions

In short-term storage, the analytes were more stable at 4 ºC than at room temperature, whereas in long-term storage they were more stable at - 80 ºC than at – 20 ºC.

Lactate Dehydrogenase and β-Glucuronidase as Salivary Biochemical Markers of Periodontitis Among Smokers and Non-Smokers

Objectives

This study aimed to establish lactate dehydrogenase (LDH) and β-glucuronidase as salivary biomarkers of periodontitis among smokers and non-smokers.

Methods

This cross-sectional case-control study was conducted at the Aligarh Muslim University, Aligarh, India, between January and June 2017. A total of 200 participants were divided into four groups based on their periodontal and smoking statuses. Unstimulated mixed saliva samples were collected to estimate LDH and β-glucuronidase levels. In addition, total protein was estimated using Lowry's method.

Results

There was a significant increase in enzyme activity in the periodontitis groups compared to the non-periodontitis groups (P <0.001). However, significantly lower enzyme activity was observed among smokers, irrespective of periodontal status (P <0.001). Nevertheless, a receiver operating characteristic curve analysis indicated the diagnostic potential of both enzymes to be fair-to-excellent.

Conclusion

Although smoking was found to significantly alter enzyme activity, LDH and β-glucuronidase were reliable salivary biomarkers of periodontitis among both smokers and non-smokers.

Estimation of Salivary and Serum Lactate Dehydrogenase in Oral Submucous Fibrosis

AIM AND OBJECTIVES

The objective of the present study was to estimate the serum and salivary lactate dehydrogenase (LDH) levels in patients with oral submucous fibrosis (OSMF) and to study the association between serum and salivary LDH levels and mouth opening, frequency of habit, and duration of habit in patients with OSMF.

MATERIALS AND METHODS

Participants were divided into two groups: Group I - case group diagnosed with OSMF and Group II - the control group. Unstimulated whole saliva was collected from all the participants. The International Federation of Clinical Chemistry method was carried out with the help of LDH (P-L) kit (Crest Biosystems, Goa). Collection of blood sample was done under aseptic precautions and processed for LDH. The data were analyzed using SPSS software 2010 (version 19, IBM, Armonk, NY, USA). Descriptive statistics including mean, range, standard deviation, and percentage were used along with unpaired t-test and Pearson's correlation test.

RESULTS

All the participants were male and were in the age range of 18-60 years, with a mean age of 28.63 ± 10.39 years. The mean salivary LDH levels in patients with OSMF were 1057.30 ± 640.12 μg/dl and in the control group were 668.25 ± 498.45 μg/dl. The mean serum LDH level in patients with OSMF was 408.35 ± 158.35 μg/dl as compared to the control group was 313.05 ± 82.69 μg/dl. The Pearson's correlation coefficient between serum LDH and frequency of habit, duration of habit, and mouth opening was found to be 0.55, 0.53, and 0.69, respectively. The Pearson's correlation coefficient between salivary LDH and frequency of habit, duration of habit, and mouth opening was found to be 0.33, 0.04, and 0.13, respectively. The Pearson's correlation coefficient between salivary LDH and serum LDH was found to be -0.18.

CONCLUSIONS

There was a significant increase in the serum and salivary LDH in OSMF patients as compared to controls; the salivary LDH did not seem to correlate with frequency of the habit, duration of the habit, or mouth opening of OSMF patients. However, serum LDH was found to correlate directly with frequency of the habit and mouth opening in OSMF patients. Hence, based on the results of the present study, it can be hypothesized that serum LDH is a better biological marker than salivary LDH in the evaluation of OSMF.

Altered Salivary Profile in Heavy Smokers and its Possible Connection to Oral Cancer

Saliva is the first biological fluid to encounter inhaled cigarette smoke, whose numerous carcinogens and oxidants are responsible for the oral cancer so prevalent among smokers. Whole saliva, collected from 25 consenting heavy smokers and from a control group of 25 age- and gender-matched non-smokers, was subjected to sialochemical, biochemical, immunological and oxidative analyses. The mean flow rate was significantly higher in smokers than in non-smokers, as were the median activity value of superoxide dismutase (SOD) and the total salivary antioxidant capacity (ImAnOx) (by 32% and 12%, respectively, p=0.05). The salivary carbonyl concentration (an oxidative stress indicator) was significantly higher by 126% (p=0.0006) among smokers, while lactate dehydrogenase, albumin, total immunoglobulin G, and the metalloproteinases MMP-2 and MMP-9 concentrations were significantly lower in the smokers, by 86% (p=0.003), 65% (p=0.003), 61% (p=0.048), 35% (p=0.005) and 55% (p=0.035), respectively. Apparently, the oral cavity's salivary antioxidant system fails to cope with the severe attack of reactive oxygen species originating in cigarette smoke. Moreover, various other salivary functional and protective parameters also decreased among the smokers. Hence, further research aimed at examining the possibility of administration of agents as antioxidants or saliva substitutes to the oral cavity of smokers should be considered.

Validity of a New Kit Measuring Salivary Lactate Dehydrogenase Level for Screening Gingivitis

Aim. The aim of this study was to determine the usefulness of a new kit that can evaluate salivary lactate dehydrogenase (LD) level in real time for screening gingivitis. Materials and Methods. The study included 70 systemic healthy volunteers [29 males and 41 females; mean age ± SD: 24.1 ± 2.6 years]. Resting saliva was collected from each participant and LD level was evaluated in real time using the kit (a color-changing sheet with an integer scale ranging from 1 to 10). A dentist measured probing pocket depth, clinical attachment level, and the proportion of sites with bleeding on probing (% BOP) at six sites on all teeth. Gingivitis was diagnosed when the BOP value was ≥20%. Results. Salivary LD level was positively correlated with mean % BOP (odds ratio: 1.47, 95% confidence interval: 1.132–1.916, and P < 0.001) in a logistic regression model. The sensitivity and specificity of the kit were 0.89 and 0.98, respectively, at a cut-off value of 8.0 for LD level. Conclusions. The new kit for measurement of salivary LD level may be a useful tool to screen for gingivitis in young adults, which contributes to early detection of future periodontitis.

A highly selective and sensitive fluorescent probe for lactate dehydrogenase based on ultrabright adenosine monophosphate capped gold nanoclusters

The ultrabright AuNCs@AMP are used as fluorescence probe to detect lactate dehydrogenase (LDH) with high sensitivity and selectivity, showing an extremely low detection limit of 0.2 nM (26 pg μL⁻¹, 0.8 U L⁻¹).

Salivary lactate dehydrogenase and aminotransferases in diabetic patients

Diabetes mellitus (DM) is a group of metabolic diseases resulting from impaired insulin secretion and/or action. DM is characterized by hyperglycemia that can lead to the dysfunction or damage of organs, including the salivary glands.The aim of this study was to compare the levels of salivary lactate dehydrogenase (LDH), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) in diabetic patients.The study was approved by the Bioethics Committee of Wroclaw Medical University (Poland). The study comprised 90 adults of both sexes, aged 21 to 57 years. The patients were divided into 3 groups: type 1 diabetics (D1), type 2 diabetics (D2), and a healthy control group (C). Each group consisted of 30 age- and sex-matched subjects. Total protein (P, by Lowry method), LDH, AST, ALT (with Alpha Diagnostics kits), and salivary flow rate were measured in unstimulated mixed saliva. The level of glycosylated hemoglobin (HbA1c) was measured with DCA 2000 Reagent Kit. The obtained data were analyzed using the Mann-Whitney U test and the Spearman rank at a significance level of P < 0.05 with the use of STATISTICA 9.0 software.In comparison with C, D1 presented a significantly higher activity of LDH (P < 0.001), AST (P < 0.001), and ALT (P < 0.01), whereas D2 indicated higher levels of LDH (P < 0.001) and ALT (P < 0.05) compared with C. Comparing D1 to D2, approximately 3-fold higher activity of AST (P < 0.01) and approximately 4.5-fold higher activity of ALT (P < 0.01) was observed.Higher levels of salivary LDH, AST, and ALT in D1 compared with D2 and C confirm that salivary glands of D1 might be attributed to autoimmunological damage associated with the pathomechanism of DM.

A new screening method for periodontitis: an alternative to the community periodontal index

Background

Periodontal screening plays an important role in the prevention of periodontal disease and promotes an improvement in oral health-related quality of life. The World Health Organization’s Community Periodontal Index should be carried out by well-trained dentists. However, the Community Periodontal Index is an invasive technique, and if used for periodontal screening, increases the cost of evaluation. In order to overcome these issues, we developed saliva tests for periodontal screening. The purpose of this study was to calculate the sensitivity and specificity of our method for measuring hemoglobin and lactate dehydrogenase levels in saliva.

Methods

Inclusion criteria were adults aged over 20 years with at least 20 teeth remaining. The study population comprised 38 men and 54 women with a mean age of 50.03 years. Oral examinations were carried out by dentists, and the number of remaining teeth, presence or absence of calculus, bleeding on probing and pocket depth were recorded. In this study, periodontitis was defined according to the criteria of the Center for Disease Control and Prevention in partnership with the American Academy of Periodontology. In order to examine hemoglobin and lactate dehydrogenase levels in saliva, participants were instructed to chew on a standard-sized tasteless and odorless gum base for 5 min, during which time, stimulated whole saliva was continuously collected.

Results

The sensitivity and specificity for hemoglobin levels were 0.759 and 0.763, respectively, and 0.722 and 0.711, respectively, for lactate dehydrogenase levels. Combining these two tests, when samples tested positive for both hemoglobin and lactate dehydrogenase, the positive predictive value was 91.7 %.

Conclusion

Measuring hemoglobin and lactate dehydrogenase levels in saliva is a less invasive method than the Community Periodontal Index. Therefore, our saliva tests may be a viable alternative to the Community Periodontal Index for periodontal screening.

Salivary Lactate Dehydrogenase (LDH)- A Novel Technique in Oral Cancer Detection and Diagnosis

INTRODUCTION

Oral squamous cell carcinoma (OSCC) is the sixth most common malignancy which is a major cause for cancer morbidity and mortality worldwide. Early diagnosis and intervention improves the overall survival rate.

AIM

The current study was done to evaluate the accuracy of salivary LDH as a potential biomarker for diagnosis of OSCC and to correlate the levels of salivary LDH with the histological differentiation of the tumour.

MATERIALS AND METHODS

Thirty patients visiting the outpatient department diagnosed clinically and histologically with OSCC were selected for the study with a control group of 20 patients. Unstimulated salivary samples collected from the selected patients were centrifuged and processed. Readings of enzyme activity in the salivary samples was established through auto analysis using International Federation of Clinical Chemistry (IFCC) method. Levels of the enzyme activity in both the control and the study group were compared and statistically analysed using student t-test. The three subgroups were also compared and statistically analysed.

RESULTS

The results showed a mean value of 497.00 with a SD of 51.75 among the control group and a mean value of 1225.40 with a SD of 221.79 among the cases with a p-value of 0.0001 which was statistically significant. Furthermore, when the LDH values for the various grades of OSCC were compared, the mean values were 1049.07, 1309.50 and 1586.20 respectively, for well differentiated, moderately differentiated and poorly differentiated carcinoma.

CONCLUSION

The p-value thus obtained revealed LDH values which were significantly higher in patients with OSCC and furthermore the levels significantly correlated with the histopathological grade of the tumour.

Equating salivary lactate dehydrogenase (LDH) with LDH-5 expression in patients with oral squamous cell carcinoma: An insight into metabolic reprogramming of cancer cell as a predictor of aggressive phenotype

Oral squamous cell carcinoma (OSCC) is the sixth most common human malignancy. According to World Health Organization, oral cancer has been reported to have the highest morbidity and mortality and a survival rate of approximately 50 % at 5 years from diagnosis. This is attributed to the subjectivity in TNM staging and histological grading which may result in less than optimum treatment outcomes including tumour recurrence. One of the hallmarks of cancer is aerobic glycolysis also known as the Warburg effect. This glycolytic phenotype (hypoxic state) not only confers immortality to cancer cells, but also correlates with the belligerent behaviour of various malignancies and is reflected as an increase in the expression of lactate dehydrogenase 5 (LDH-5), the main isoform of LDH catalysing the conversion of pyruvate to lactate during glycolysis. The diagnostic role of salivary LDH in assessing the metabolic phenotype of oral cancer has not been studied. Since salivary LDH is mainly sourced from oral epithelial cells, any pathological changes in the epithelium should reflect diagnostically in saliva. Thus in our current research, we made an attempt to ascertain the biological behaviour and aggressiveness of OSCC by appraising its metabolic phenotype as indirectly reflected in salivary LDH activity. We found that salivary LDH can be used to assess the aggressiveness of different histological grades of OSCC. For the first time, an evidence of differing metabolic behaviour in similar histologic tumour grade is presented. Taken together, our study examines the inclusion of salivary LDH as potential diagnostic parameter and therapeutic index in OSCC.

Histopathological differentiation of oral squamous cell carcinoma and salivary lactate dehydrogenase: A biochemical study

Context:

Early diagnosis of oral cancer is a priority health objective, in which oral health professionals may play a pivotal role. Detection should lead to less damage from cancer therapy and to a better prognosis.

Aims:

The aim was to estimate and compare the salivary lactate dehydrogenase (LDH) levels in various histological differentiation of oral squamous cell carcinoma (OSCC) patients and normal subjects.

Settings and Design:

Hospital-based setting, case-control study.

Subjects and Methods:

A case–control study was undertaken comprising 30 OSCC patients and 30 healthy controls. The OSCC patients were grouped into well-differentiated, moderately differentiated and poorly differentiated OSCC based on their histological tumor differentiation. Unstimulated whole saliva was collected, assayed for LDH levels using a standard kit and measured spectrophotometrically at 340 nm.

Statistical Analysis Used:

The results obtained were subjected to statistical analysis using Kruskal–Wallis and Mann–Whitney U-tests. Spearman's correlation was used to correlate the histological tumor differentiation with the salivary LDH levels.

Results:

The mean salivary LDH levels in the control group, well-differentiated OSCC group, moderately differentiated OSCC group, and poorly differentiated OSCC group were 117.33 ± 19.37 IU/L, 355.83 ± 16.73 IU/L, 484.18 ± 25.84 IU/L, and 620.35 ± 18.69 IU/L, respectively. The difference in the mean salivary LDH levels was statistically significant among the various groups (Kruskal–Wallis χ² = 50.820, P < 0.001). Spearman's correlation showed significant difference between salivary LDH levels and histological differentiation of OSCC (r = −0.689, P < 0.01).

Conclusions:

The salivary LDH levels were higher in OSCC patients when compared to the healthy controls. The salivary LDH levels were found to be the highest among the poorly differentiated OSCC.

A study of salivary lactate dehydrogenase isoenzyme levels in patients with oral leukoplakia and squamous cell carcinoma by gel electrophoresis method

Context:

The enzyme lactate dehydrogenase (LDH), which is found in almost all the cells of body tissues, can be separated into five fractions and the isoenzyme pattern is believed to vary according to the metabolic requirement of each tissue. LDH concentration in saliva, as an expression of cellular necrosis, could be considered to be a specific indicator for oral lesions that affect the integrity of the oral mucosa.

Aim:

The present study was designed to evaluate salivary LDH isoenzyme pattern in oral leukoplakia (OL) and oral squamous cell carcinoma (OSCC) and to correlate between LDH isoenzyme levels and histopathologic grading in selected cases of OL and OSCC.

Materials and Methods:

Clinically diagnosed 30 cases each of OL and OSCC were selected for the study and 30 healthy individuals of comparable age served as control. Unstimulated whole saliva was aseptically collected and was processed immediately for LDH isoenzymes measurement by agarose gel electrophoresis. Biopsy specimen obtained was processed and stained by hematoxylin and eosin. Sections of OL and OSCC cases were scrutinized histopathologically and appropriately graded for epithelial dysplasia and differentiation of carcinoma respectively.

Statistical Analysis Used:

Two sample t test for testing the significance of difference between two group means was used.

Results and Conclusion:

The present salivary analysis for LDH isoenzyme reveals an overall increased salivary LDH isoenzyme level in OL and OSCC cases and a significant correlation between levels of salivary LDH isoenzymes and histopathologic grades of dysplasia in OL and OSCC. Salivary analysis of LDH will definitely provide the clinician and/or the patient himself with an efficient, non invasive and friendly new tool for diagnosis and monitoring of oral precancer and cancer.

Oxidative stress in the oral cavity: sources and pathological outcomes

Oxidative stress (OS), an imbalance in the oxidant-antioxidant equilibrium, is thought to be involved in the development of many seemingly unrelated diseases. Oral cavity tissues are a unique environment constantly exposed to internal and external compounds and material hazards as almost no other part of the human body. Some of the compounds are capable of generating OS. Here, the main groups of endogenous as well as exogenous OS sources are presented, followed by their oxidative effect on the salivary contents and function. The oxidative mechanisms in oral cells and their pathologic influence are also discussed.

Evaluation of lactate dehydrogenase enzyme activity in saliva and serum of oral submucous fibrosis patients

BACKGROUND

Of all oral precancerous conditions, Oral Submucous Fibrosis is of greater concern because of its disabling nature and relative greater chances of malignant transformation. This malignant transformation involves glycolytic pathways that can alter lactate dehydrogenase levels. Therefore the aim of this study was to estimate the LDH levels in saliva and serum of subjects with OSMF and to compare them with healthy controls and to correlate the relationship between pathogenesis of OSMF and the LDH enzyme.

METHODS

Sixty Subjects were recruited for this study and divided into two groups, 30 subjects with OSMF (Group A) and 30 healthy controls (Group B). Venous blood and unstimulated whole saliva measuring 1 ml was collected from each of these evaluated for LDH levels using the standard kit method. The data obtained were subjected to statistical analysis using the SPSS software version 17.

RESULTS

The average salivary LDH value for Group A was 606.83 ± 60.09 U/l and for Group B was 80.73 ± 20.06 U/l. salivary LDH was greater in group A than Group B and this was statistically significant. On comparing the serum and salivary LDH in Group A with the clinical staging of OSMF, the results were not statistically significant. Similarly no statistically significant relationship was found on comparing the serum and salivary LDH in Group A (OSMF subjects) with duration of habit.

CONCLUSION

This study provides additional rationale for the role of salivary LDH in the early diagnosis and prognosis of oral submucous fibrosis.

Oxidative damage in keratinocytes exposed to cigarette smoke and aldehydes

Cigarette smoke (CS) is a significant environmental source of human exposure to chemically active saturated (acetaldehyde) and α,β-unsaturated aldehydes (acrolein) inducing protein carbonylation and dysfunction. The exposure of oral tissues to environmental hazards is immense, especially in smokers. The objectives of the current study were to examine the effect of aldehydes originating from CS on intracellular proteins of oral keratinocytes and to observe the antioxidant response in these cells. Intracellular protein carbonyl modification under CS, acrolein and acetaldehyde exposure in the HaCaT keratinocyte cell line, representing oral keratinocytes was examined by Western blot. Possible intracellular enzymatic dysfunction under the above conditions was examined by lactate dehydrogenase (LDH) activity assay. Oxidative stress response was investigated, by DCF (2,7-dichlorodihydrofluorescein) assay and GSH (glutathione) oxidation. Intracellular protein carbonyls increased 5.2 times after CS exposure and 2.7 times after exposure to 1 μmol of acrolein. DCF assay revealed an increase of fluorescence intensity 3.2 and 3.1 times after CS and acrolein exposure, respectively. CS caused a 72.5% decrease in intracellular GSH levels compared to controls. Activity of intracellular LDH was preserved. α,β-Unsaturated aldehydes from CS are capable of intracellular protein carbonylation and have a role in intracellular oxidative stress elevation in keratinocytes, probably due to the reduction in GSH levels.

Salivary biomarker analysis complementing regular clinical examination

AIM

Tools for the diagnosis and evaluation of the severity and prognosis of periodontitis are currently insufficient. The aim of the current study was to find an array of salivary biomarkers that would be both sensitive and specific enough to be used as a complement to regular clinical examination. Furthermore, we investigated salivary markers of successful periodontal treatment to elucidate the underlying mechanism of disease.

PATIENTS & METHODS

Saliva was collected from periodontitis patients during illness and following successful disease termination. Parameters measured included sodium, potassium, chloride, calcium, phosphate, magnesium, total protein, Alb, LDH, amylase, IL-1α, uric acid and carbonyls.

RESULTS

Seven of the parameters analyzed were significantly altered when the disease is active and may be considered biomarkers.

CONCLUSION

Salivary composition reflects disease severity and response to therapy, suggesting the efficacy of saliva monitoring for periodontal disease status and care.

LDH enzyme activity in human saliva: the effect of exposure to cigarette smoke and its different components

OBJECTIVE

Aldehydes and reactive nitrogen species (RNS) are important chemically active agents in cigarette smoke (CS). Salivary lactate dehydrogenase (LDH) originates predominantly from oral epithelium and was identified as an oral state marker. Its activity in saliva decreases after CS exposure. The aims of the current study were to identify the specific damaging agents in CS responsible for this activity reduction and to understand the mechanisms participating in CS oxidative damage to the salivary enzymes.

METHODS

Purified and salivary LDH samples were exposed to different levels of CS, pure acrolein, acetaldehyde, peroxynitrite and RNS donors. Each response of the isolated agent to the exposure was examined by a spectrophotometric enzyme activity assay and a Western blot.

RESULTS

CS exposure caused a 34% reduction in LDH activity. Isolated treatment with unsaturated-aldehydes (acrolein, 10μmol) caused a 61% reduction, while saturated-aldehydes (acetaldehyde, 200μmol), peroxynitrite (200μM) and RNS donor (SIN-1, 2mM) caused no substantial effect. All five LDH isoenzymes reacted similarly. The carbonyl immunoblotting assay revealed a fourfold increase in carbonyl content when treated with CS and a sevenfold increase when treated with acrolein.

CONCLUSION

α,β-Unsaturated-aldehydes were identified as the main CS ingredient responsible for salivary LDH activity diminution. The effect of saturated-aldehydes and RNS donors was negligible. Unsaturated-aldehydes are capable of introducing carbonyl group into proteins, causing their dysfunction. This provides a molecular explanation for a decrease in LDH enzymatic activity in saliva.

Time and dose effects of cigarette smoke and acrolein on protein carbonyl formation in HaCaT keratinocytes

Cigarette smoke (CS) is an important environmental source of human exposure to a highly toxic and chemically active α,β-unsaturated aldehyde: acrolein. It is capable of causing protein carbonylation and dysfunction, especially in oral tissues of smokers, constantly exposed to CS toxic constituents. The foremost damage is considered to be cumulative, but even a short exposure can be potentially harmful. The objectives of the current study were to examine the short time and dose effects of direct CS and acrolein exposure on intracellular protein carbonylation in epithelial cells. HaCaT-keratinocytes were exposed to different doses of acrolein and whole phase CS using a unique smoking simulator apparatus that mimics the exposure in smokers. The rate of intracellular protein carbonyl modification was examined 10-60 min after the exposure by Western blot. In addition, the effect of pre-incubation with a thiol scavenger N-acetylcysteine (NAC) was also assessed. We found that intracellular protein carbonyls increased as fast as 10 min after CS exposure and their concentration doubled after 20 min, with a slight elevation afterwards. Also, carbonyl levels increased gradually as CS and acrolein doses were elevated. Addition of 1 mM NAC neutralized part of the damage. We conclude that CS and acrolein intracellular protein carbonylation is dose- and time- dependent. Even a short time exposure to CS and its aldehydic constituents can be potentially harmful.

Salivary enzymes in peptic ulcer disease

AIM

Peptic ulcer, the common disease of the upper gastro-intestinal tract, occurs in about 5-10% of the world's population. Therefore, diagnosis of trace disease progression with a noninvasive method is of prime importance in the field of healthcare research. The aim of this study was to evaluate the validity of salivary enzymes as noninvasive biomarkers for peptic ulcer.

MATERIALS AND METHODS

In practice, 34 peptic ulcer patients and 30 healthy subjects donated their un-stimulated saliva samples after 8 h of fasting. The activity of some selected enzymes was measured using appropriate enzymatic assay methods.

RESULTS

The results indicated an overall alternation in enzymatic activity of saliva in patients suffering from peptic ulcer. Biological activity of a-amylase, peroxidase and lactate dehydrogenase, showed significantly higher values in almost all patients as compared to control subjects.

CONCLUSIONS

Based on the results of salivary enzyme activity, it was concluded that besides the influence of their peptic ulcer on enzyme activity of saliva, the considerably higher activity of a-amylase could also be related to the major role of the enzyme on physiological oxidative stress.

Role of lipid oxidation, chelating agents, and antioxidants in metallic flavor development in the oral cavity

This study investigated the production of metallic flavor, which is a combination of taste and retronasal odor. Chemical reactions in the oral cavity and saliva of healthy subjects were investigated after ingesting iron and copper solutions above and near threshold levels. Significant increase in lipid oxidation (p < 0.001) occurred after metal ingestion, detected as TBARS values. Ferrous ion caused the greatest flavor sensation and lipid oxidation, followed by cupric and cuprous ions. Ferric ion did not cause metallic sensation. Occurrence of oxidation was supported by damage to salivary proteins, detected as protein-carbonyls, and by a significant increase of odorous lipid oxidation related aldehydes. Sensory evaluation demonstrated that antioxidants (vitamins E and C) minimally reduced metallic flavor but that chelating agents (EDTA and lactoferrin) removed the metallic flavor. The role of lipid oxidation is essential for the production of a metallic flavor from ingestion of ferrous, cupric, and cuprous ions.

Binding ligands and cofactor to L-lactate dehydrogenase from human skeletal and heart muscles

Binding affinities of cofactor and ligands to the active site of two different isoforms of lactate dehydrogenase (LDH), heart and skeletal muscles (H4 and M4, respectively), can be used for medical and biological applications. Herein, a hybrid QM/MM computational approach based on free energy perturbation methods has been carried out to estimate binding affinities and binding isotope effects (BIEs) for NADH/NAD(+) and oxamate, pyruvate, L-lactate, and D-lactate ligands to the M4 and H4 isoforms of L-LDH. Here, we show that determining how cofactor and ligands interact with the active site of LDH isoforms advanced the still open discussion on the intracellular lactate shuttle hypothesis. In our discussion we deny the key concept of this hypothesis showing, based on interaction energy values, that there is no evidence that the M4 type of LDH in the skeletal muscles cells served as a catalyst of the conversion of lactate to pyruvate. Additionally, theoretical determination of BIEs for H4 and M4 types of LDH shows that there is a way of using the BIEs as a tool capable to distinguish these isoforms, and for this purpose D-lactate labeled with deuterium in positions 11 or 7, 8, 9 ([11-2H]-BIE and [7,8,9-2H3]-BIE) or L-lactate labeled only in position 11 ([11-2H]-BIE) could be used. We propose the BIEs as a useful tool which can be applied in order to experimentally determine the types of LDH.

Salivary monitoring related to major surgery

BACKGROUND

Prolonged surgical procedures involving stress, extended general anaesthesia and a long pre-surgical fasting period may have systemic effects such as alterations in saliva flow rate and composition. These may compromise the patient's electrolytes and fluid balance and cause dehydration, systemic stress and oxidative changes.

PATIENTS AND METHODS

Saliva was collected prior and following surgery from 20 patients and 20 control subjects. The saliva samples were analysed for flow rates and levels of the following: calcium (Ca), magnesium (Mg), total protein, albumin and lactate dehydrogenase (LDH), total antioxidant status (TAS), uric acid (UA), superoxide dismutase (SOD), carbonyls, matrix metalloproteinases (MMPs) -2, -3 and -9 and heat shock proteins (HSPs) 70 and 90.

RESULTS

Salivary levels of Ca, Mg, protein, albumin and LDH were higher in post-surgical patients by 70% (P = 0·002), 88% (P = 0·0001), 120% (P = 0·13), 111% (P = 0·039) and 492% (P = 0·006) respectively than that in healthy controls. Salivary antioxidants in the surgical patients were higher while salivary carbonyls remained unchanged. Salivary TAS levels in pre- and post-surgical patients were higher by 63% (P = 0·001) and 85% (P = 0·0001) respectively, UA concentrations by 92% (P = 0·014) and 81% (P = 0·036) respectively and SOD values by 47% (P = 0·61) and 112% (P = 0·049) respectively. Salivary concentrations of MMP3 were higher in pre- and post-surgical patients by 23% (P = 0·067) and 30% (P = 0·044) respectively.

CONCLUSIONS

Local salivary, oral and systemic-induced alterations should be prevented. Moreover, salivary collection and analysis may be a new, efficient tool in the monitoring of patients undergoing major surgery. Further related research is necessary.

Diagnostic clinical aids in oral cancer

Conventional oral exploration (visual and palpation examination) constitutes the current gold standard for oral cancer screening, while biopsy and histopathological examination represents the indispensable study for the detection of cases in patients with an identified lesion. Imaging techniques (DPT, CT, and MRI) are frequently used to supplement the clinical evaluation and staging of the primary tumour and regional lymph nodes. There are also a number of techniques that may contribute to the diagnosis of oral cancer: toluidine blue test has been used as a diagnostic aid for the detection of oral cancer over decades. Recently developed light-based detection systems have progressively improved in sensitivity and specificity, but multicentre controlled studies conducted by general dental practitioners must be designed in order to justify their application. The oral brush biopsy appears to overestimate dysplastic lesions and produces a high number of false-positive results. In the near future, immunological and biochemical alterations in the serum (e.g., circulating immune complexes, carcinoembryonic antigen, squamous cell carcinoma associated antigen, inhibitor of apoptosis, cytokeratin fragments, and annexin A1) as well as specific saliva analysis (e.g., cancer related cytokines, metalloproteinases, epithelial tumour markers, DNA promoter hypermethylation, and saliva micro-RNA) may become important tools for the detection of oral cancer.

Oral cancer, cigarette smoke and mitochondrial 18kDa translocator protein (TSPO) - In vitro, in vivo, salivary analysis

Oral cancer features high rates of mortality and morbidity, and is in dire need for new approaches. In the present study we analyzed 18 kDa translocator protein (TSPO) expression in oral (tongue) cancer tumors by immunohistochemistry. We also assayed TSPO binding in human tongue cancer cell lines and in the cellular fraction of saliva from tongue cancer patients, heavy cigarette smokers, and non-smoking healthy people as controls. Concurrently, TSPO protein levels, cell viability, mitochondrial membrane potential (Deltapsi(m)), and general protein levels were analyzed. TSPO expression could be significantly enhanced in oral cancer tumors, compared to unaffected adjacent tissue. We also found that five-year survival probability dropped from 65% in patients with TSPO negative tumors to 7% in patients with highly expressed TSPO (p<0.001). TSPO binding capacity was also pronounced in the human oral cancer cell lines SCC-25 and SCC-15 (3133+/-643 fmol/mg protein and 6956+/-549 fmol/mg protein, respectively). Binding decreased by 56% and 72%, in the SCC-25 and SCC-15 cell lines, respectively (p<0.05) following CS exposure in cell culture. In the cellular fraction of saliva of heavy smokers TSPO binding was lower than in non-smokers (by 53%, p<0.05). Also the cellular fraction of saliva exposed to CS in vitro showed decreased TSPO binding compared to unexposed saliva (by 30%, p<0.001). Interestingly, oral cancer patients also displayed significantly lower TSPO binding in the cellular fraction of saliva compared to healthy controls (by 40%, p<0.01). Our results suggest that low TSPO binding found in the cellular fraction of saliva may depend on genetic background as well as result from exposure to CS. We suggest that this may be related to a predisposition for occurrence of oral cancer.

Salivary antioxidants and metalloproteinases in juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is the most common autoimmune inflammatory disease in children; joint inflammation is the hallmark of the disease. Thirty-five children with JIA were studied, of whom 26 had active disease and 14 were receiving anti-TNF therapy (5 with Infliximab, 9 with Etanercept). Sixteen healthy controls also were studied. Saliva samples were obtained for analysis of anti-oxidant status, metalloproteinases (MMPs) and sialochemistry. The total antioxidant status was significantly higher in the saliva of all JIA patients, whether treated (P = 0.014) or not treated (P = 0.038) with anti-TNF agents. The increase in antioxidant status (TAS) in the saliva of the active patients was nearly two times higher than that of non-active patients (P = 0.01). MMP levels were significantly lower in JIA patients than in controls. MMP-9, MMP-3 and MMP-2 were lower in JIA patients without anti-TNF treatment by 36.7% (P = 0.01), 30.0% (P = 0.0001) and 10.7% (P = 0.0001), respectively. A greater reduction in MMP levels was observed in the group of patients treated with anti-TNF drugs: MMP-9, MMP-3 and MMP-2 were lower than in controls by 51.1% (P = 0.0001), 61.5% (P = 0.0001) and 55.4% (P = 0.0001), respectively. Children with JIA exhibited a significantly higher salivary antioxidant activity and significantly lower MMP levels. Anti-TNF treatment was associated with a further decrease in MMP levels in the saliva of JIA patients while an active state of JIA was associated with a further increase in the salivary antioxidant activity. Anti-TNF treatment may modulate the degradation process during the course of arthritis by inhibition of the activity of MMP.

Salivary profile and oxidative stress in children and adolescents with cystic fibrosis

BACKGROUND

Cystic fibrosis (CF) is characterized by altered exocrine secretions; however, no comprehensive compositional profile of CF serous and mucous saliva secretions has been published.

DESIGN

We analyzed salivary flow rate and composition, and oxidative stress-related parameters, comparing CF patients with non-CF bronchiectasis patients and the healthy controls.

RESULTS

Median salivary magnesium concentration and lactate dehydrogenase activity were significantly lower in CF patients than in the healthy controls. Salivary total protein concentration was 45% higher in CF patients than in non-CF bronchiectasis patients. CF patients showed 8% lower levels of peroxidase compared with non-CF bronchiectasis. Salivary total antioxidant status, superoxide dismutase and uric acid values in the CF group were higher by 15%, 35% and 31%, respectively, than in both control groups.

CONCLUSIONS

Cystic fibrosis patients demonstrated altered salivary profile, especially in antioxidant enzymatic and molecular activity, possibly resulting from the oral cavity's ongoing inflammatory and oxidative process. Free radical mechanisms may be involved in CF pathogenesis.

Compositional and oxidative analysis in the saliva and serum of predialysis chronic kidney disease patients and end-stage renal failure patients on peritoneal dialysis

Chronic renal failure (CRF) is often treated with peritoneal dialysis, although increased oxidative stress has been reported in such patients. The purpose of the current study was to analyze and compare oxidative stress and other compositional parameters in the saliva, serum and peritoneal dialytic fluid (PDF) of patients with chronic kidney disease (CKD), including predialysis CKD patients and end-stage renal disease (ESRD) patients treated with peritoneal dialysis. Twenty-three consenting patients participated in the current study. Saliva and serum samples collected from both groups and PDF from the dialysis patients were all examined for uric acid (UA), total antioxidant status, total protein and total albumin. The antioxidant enzyme peroxidase was examined both in saliva and serum, while the antioxidant enzyme superoxide dismutase (SOD) was examined solely in saliva. Various electrolytes were examined. Discrepancies were found between saliva and serum antioxidant status following peritoneal dialysis in ESRD patients. Oxidative stress was enhanced in the saliva but reduced in the serum. Significant changes in both oxidative-related and non-related parameters were demonstrated in saliva, serum and PDF. Salivary lactate dehydrogenase was substantially lower in the dialysis patients (by 92%, P = 0.02), as was the salivary UA concentration (by 22%, P = 0.05) and serum UA concentration (by 20%, P = 0.03). In contrast, salivary peroxidase and SOD were higher by 15% and 35%, respectively (P = 0.01), in these patients. We suggest monitoring salivary UA for assessing the baseline oral oxidative status of CRF and dialyzed patients.

Screening for periodontitis in pregnant women with salivary enzymes

AIM

To develop a test for the screening of pregnant women for periodontitis using saliva prior to a dental examination.

METHODS

A cross-sectional research design was employed. Whole unstimulated saliva was collected from 221 pregnant women prior to a dental examination at the Amagasaki Public Health Office and levels of activity of lactate dehydrogenase (LDH) and alkaline phosphatase (ALP), and of occult blood in the saliva were measured. The data were compared with Community Periodontal Index of Treatment Needs (CPITN) scores. The diagnostic performance of LDH, ALP, and occult blood was determined in terms of sensitivity, specificity, and the area under receiver operating characteristics (ROC) curves. The optimal combination of parameters for screening periodontitis was determined at maximum sensitivity and specificity.

RESULTS

Periodontitis (CPITN 3, 4) in 19 women (8.6%) and gingivitis (CPITN 1, 2) in 129 women (58.4%) were observed. The activity levels of LDH and ALP were significantly higher in the pregnant women with periodontitis than those with gingivitis or a healthy periodontium. To distinguish between the pregnant women with periodontitis and the others, a cut-off value of 684 IU/L for LDH and of 75 IU/L for ALP were determined by a ROC analysis. The test combining LDH, ALP, and occult blood showed the highest diagnostic performance; with a sensitivity value of 0.90, specificity value of 0.62, positive predictive value of 0.18, and negative predictive value of 0.98.

CONCLUSIONS

A test combining the parameters salivary LDH, ALP and occult blood is useful for screening pregnant women for periodontitis.

Salivary and gustatory alterations among bulimia nervosa patients

OBJECTIVE AND DESIGN

This study systematically examined salivary composition and taste perception and monitored related subjective complaints in a group of bulimia nervosa (BN) patients.

SUBJECTS

Fifty-two consenting female individuals participated in the current cross-sectional study, 26 patients diagnosed with BN according to the Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV) criteria (mean age: 24+/-7 years) and 26 healthy controls matching in age and body mass index (BMI).

METHODS

All participants were given diagnostic BN-related questionnaires, had taste and salivary-composition analyses and were monitored for oral sensorial complaints. The patients were also subjected to psychological and psychiatric examinations focusing on established criteria known to be pathognomonic of the disease (including binge eating episodes, depression, impulsive traits, enhanced awareness of body image, typical compensatory behavior, and so on).

RESULTS

The self-answered questionnaires of Bulimic Investigatory Test Edinburgh (BITE), Beck Depression Inventory (BDI), brief symptom inventory (BSI) and impulsivity scale (IS) revealed highly significant differences between the two groups with respect to the various BN diagnostic symptoms of the patients (P=0.0001). Subjective and objective examinations showed an overall disturbed salivary and taste profile in BN patients, who complained of xerostomia (dry mouth) and taste aberration or oral burning sensation.

CONCLUSIONS

Regardless of the specific mechanism responsible for the disturbed salivary and taste profile in BN patients, these observed changes are associated with active illness. Accordingly, administration of therapeutic agents, including antioxidants, anti-inflammatory drugs and saliva substitutes, to the oral cavity (and maybe even systemically) of BN patients should be considered.