Enzymatic markers of salivary cell injury in saliva of type 1 diabetic children

Human dental pulp stem cells attenuate streptozotocin-induced parotid gland injury in rats

OBJECTIVE

Diabetes mellitus causes deterioration in the body, including serious damage of the oral cavity related to salivary gland dysfunction, characterised by hyposalivation and xerostomia. Human dental pulp stem cells (hDPSCs) represent a promising therapy source, due to the easy, minimally invasive surgical access to these cells and their high proliferative capacity. It was previously reported that the trophic support mediated by these cells can rescue the functional and structural alterations of damaged salivary glands. However, potential differentiation and paracrine effects of hDPSCs in diabetic-induced parotid gland damage have not been investigated. Our study aimed to investigate the therapeutic effects of intravenous transplantation of hDPSCs on parotid gland injury in a rat model of streptozotocin (STZ)-induced type 1 diabetes.

METHODS

Thirty Sprague-Dawley male rats were randomly categorised into three groups: control, diabetic (STZ), and transplanted (STZ + hDPSCs). The hDPSCs or the vehicles were injected into the rats' tail veins, 7 days after STZ injection. Fasting blood glucose levels were monitored weekly. A glucose tolerance test was performed, and the parotid gland weight, salivary flow rate, oxidative stress indices, parotid gland histology, and caspase-3, vascular endothelial growth factor, proliferating cell nuclear antigen, neuronal nitric oxide synthase, endothelial nitric oxide synthase, and tetrahydrobiopterin biosynthetic enzyme expression levels in parotid tissues were assessed 28 days post-transplantation.

RESULTS

Transplantation of hDPSCs decreased blood glucose, improved parotid gland weight and salivary flow rate, and reduced oxidative stress. The cells migrated to the STZ-injured parotid gland and differentiated into acinar, ductal, and myoepithelial cells. Moreover, hDPSCs downregulated the expression of caspase-3 and upregulated the expression of vascular endothelial growth factor and proliferating cell nuclear antigen, likely exerting pro-angiogenic and anti-apoptotic effects and promoting endogenous regeneration. In addition, the transplanted cells enhanced the parotid nitric oxide-tetrahydrobiopterin pathway.

CONCLUSIONS

Our results showed that hDPSCs migrated to and survived within the STZ-injured parotid gland, where functional and morphological damage was prevented due to the restoration of normal glucose levels, differentiation into parotid cell populations, and stimulation of paracrine-mediated regeneration. Thus, hDPSCs may have potential in the treatment of diabetes-induced parotid gland injury.

Salivary and Serum Aspartate Aminotransferases and Alanine Aminotransferases in Insulin-Dependent Diabetes Mellitus and Normal Children: A Comparative Study

Aims and Objectives

The aim of the study was to estimate and compare aspartate aminotransferases (AST) and alanine aminotransferases (ALT) levels in saliva and serum of insulin-dependent diabetes mellitus (IDDM) and normal children, and the objective was to evaluate the significance of these enzymes in assessing the salivary gland injury in IDDM children.

Materials and Methods

The study group comprised of thirty children clinically and biochemically diagnosed for IDDM and thirty healthy children of similar age in the control group. Saliva and serum samples were collected and enzyme assay was performed by optimized ultraviolet test method (according to International Federation of Clinical Chemistry). The values obtained were subjected to statistical analysis using Mann-Whitney U-test for comparison of the variables and Karl-Pearson's coefficient test for correlation. The SPSS 16.0, (SPSS Inc., Chicago, USA) was used for statistical analysis.

Results

Higher values of AST (mean = saliva 91.60 IU/L) and ALT (mean = saliva 94.93 IU/L) were found in the saliva than in serum (AST serum = 15.83 IU/L) (ALT serum = 20.80 IU/L) among the patients and the differences were statistically highly significant (P = 0.001). A similar comparison in the control group did not show statistical significant difference (saliva - AST mean = 23.50 IU/L, ALT mean = 21.95 IU/L and serum - AST mean = 12.60 IU/L, ALT mean = 13.25 IU/L). On correlation between patient and normal group, greater values of AST and ALT were observed in saliva of patients and the difference was statistically highly significant ([AST-mean = patients 91.166 IU/L and controls = 23.500 IU/L] [ALT-mean = patients 94.933 IU/L and controls 21.950 IU/L]). The serum values of patients and controls did not show statistical difference. Although higher values of salivary ALT and AST were observed in patients with the disease for 0-5-year clinical duration (ALT mean = 100.21 IU/L and AST mean = 95.39 IU/L) than those with the disease for 6-10-year duration (ALT mean = 77.57 IU/L and AST mean = 77.28 IU/L), values were statistically nonsignificant.

Conclusion

Elevated salivary AST and ALT levels in IDDM patients suggest the injury to salivary glands and could aid as a salivary marker for the involvement of salivary glands in IDDM.

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.

Selected antibacterial factors in the saliva of diabetic patients

OBJECTIVE

Diabetes mellitus leads to many systemic complications, including changes in the morphology, function of the salivary glands, and the composition of saliva.

DESIGN

The study comprised a randomly selected 156 adults, of both genders, aged from 21 to 79, out of which patients with diabetes type 1 and 2, and healthy subjects forming two control age- and gender matched to the ill subjects. In unstimulated mixed saliva, total protein, peroxidase, myeloperoxidase and immunoglobulin A were measured as well as salivary flow rate. The periodontal condition was assessed with the use of GI, mSBI and PSR index. The obtained data were analysed with the use of U Mann-Whitney's test, Spearman's rang correlation and Chi-square test at a significant level of p < 0.05 with use of Statistica 9.0 software.

RESULTS

Type 1 diabetics in comparison to healthy age and gender matched control group had a lower salivary flow rate (p < 0.01), a higher content of total protein (p < 0.01), myeloperoxidase (p < 0.001) and immunoglobulin A (p < 0.001). Similarly, type 2 diabetics in comparison to control subjects had a higher level of total protein concentration (p < 0.01), myeloperoxidase (p < 0.05) and immunoglobulin A (p < 0.001). We also found worse periodontal condition.

CONCLUSION

Within the limitation of the study it may be stated that diabetes type 1 and 2 can cause abnormalities in salivary glands function resulting in the diminishing of salivary flow rate and the increase in total protein content. Higher levels of myeloperoxidase and IgA in the saliva can be linked to worse periodontal condition in the diabetic patients.

A comparative study of glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) levels in the saliva of diabetic and normal patients

Diabetes has been reported to affect salivary glands adversely in humans and experimental models. Glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT) and lactate dehydrogenase (LDH) are salivary enzymes that also are widely distributed in animal tissues. We determined GOT and GPT levels in saliva samples of 100 type 1 and 30 type 2 diabetic patients using reflectance spectrophotometry and compared them to 30 age and sex matched healthy controls. Statistically significant differences were observed in the mean values of GOT and GPT in type 1 diabetics compared to type 2 and control groups. Significantly higher GOT levels were found in the 1-20 year age group of type 1 diabetics. Our findings suggest that salivary gland damage is due to the same immunological attack that affects pancreatic β cells and results in type 1 diabetes.

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.