Study On The Relationship Between The Levels Of Serum TLR-4 And The Fracture Risk In Patients With Type 2 Diabetes

Objective: Diabetes is a metabolic disease characterized by an increase of chronic blood glucose levels, which is caused by the insulin secretion and(or) the defect of its role. Long-term metabolic disorder of carbohydrate, fat and protein can cause multiple-system damage, leading to chronic progressive lesions and affecting the life quality of the patients. Although it can affect bone metabolism through a variety of mechanisms, the exact mechanism of how diabetes, especially type 2 diabetes, affects osteoporosis is still unclear. But reliable evidence suggests that type 2 diabetes can increase the risk of fractures.Toll-like receptor(Toll like receptor, TLR) is a kind of natural immune receptor, the genes of which were originally found to be associated with the development of the dorsal and ventral parts of drosophila embryo. With the deepening of the research, similar homologous receptors were also found in mammals, together classified into the TLR family.TLR is widely distributed, and mainly expressed on the surface of monocytes, macrophages, dendritic cells and polymorphonuclear cells, lymphocytes, natural killer cells, etc. Now it has been found that TLR family includes at least 13 members, and the ligands of different TLRs also vary, with TLR-4 getting particular concern at present.Studies have shown that, in patients with newly diagnosed type 2 diabetes, the expression of TLR-4 and its ligand, signaling pathway and function all increased, indicating the involvement in the formation of the state of inflammation. The continuous rise of blood glucose levels in type 2 diabetes patients affected TLR-4, activating the inflammatory signaling pathway, increasing the production of cytokines, and resulting in the chronic inflammation in patients with type 2 diabetes. The levels of fatty acid in patients with metabolic diseases, such as lipid metabolism disorder, obesity and diabetes increased. Evidence demonstrates that there exists a link among saturated fatty acid, inflammation and insulin resistance. The infusion of saturated fatty acid for healthy people can cause the formation of ROS, the enhancing of the activity of NF-κB and the increase of the levels of cytokines in plasma.TLR-4 can activate NF-κB through My D88 dependant pathway and My D88 non-dependant pathway, activate the gene expression of osteoclasts, participate in the activation of osteoclasts, and affect the bone metabolism. In addition, studies have shown that TLR-4 might affect the bone metabolism by inhibiting the classic Wnt signaling and promoting the activity of osteoclasts.This study was to explore the relationship between the level of serum TLR-4 in patients with type 2 diabetes and bone transformation, further assess the relationship between serum TLR-4 and fracture risk, and provide theoretical basis for the prevention and treatment of osteoporosis in patients with type 2 diabetes.Methods: 88 hospitalized patients with type 2 diabetes, from the department of endocrinology, the third hospital of Hebei Medical University, between January 2014 and October 2014, were chosen as the subjects, all of whom accepted the test of bone density of 3 parts through dual-energy X-ray absorptiometry, including the lumbar spine(lumbar 2-4) and bilateral hip(femoral neck, greater trochanter, intertrochanteric). According to the WHO osteoporosis diagnostic criteria(DEXA), the above subjects were divided into 3 groups: normal bone mass group of type 2 diabetes, osteopenia group of type 2 diabetes and osteoporosis(OP) group of type 2 diabetes. Respectively recorded were the relevant data, such as the patients’ gender, age, height, weight, abdominal girth, diabetes duration, etc, with the body mass index calculated, the biochemical indicators tested, such as FBG, Hb Alc, TG, TC, HDL-C and LDL-C, and the levels of serum TLR-4 determined through the enzyme-linked immunosorbent method(enzyme-linked immunosorbent assay, ELISA). The data were expressed by mean + /- standard deviation(+ /- SD), and analyzed through SPSS13.0.Results:1 After making comparisons among the levels of serum TLR-4, age, diabetes duration, BMI and Hb A1 C of the three groups through the single factor analysis of variance, results showed that the levels of serum TLR-4 were statistically different among the three groups(F=113.190, P<0.05). The results of further paired-comparisons using the LSD method showed the levels of serum TLR-4 of the osteoporosis group were higher than that of the normal bone mass group and the osteopenia group, and the levels of serum TLR-4 of the osteopenia group were higher than that of the normal bone mass group. There were also statistical differences in terms of age among the three groups(F=12.902, P<0.05). The results of further paired-comparisons using the LSD method showed that the osteoporosis group was different from the osteopenia group and the normal bone mass group, and there were no statistical differences between the osteopenia group and the normal bone mass group. There were no statistical differences in terms of diabetes duration, BMI and glycosylated hemoglobin among the three groups, with F value 0.302, 1.961 and 0.302 respectively, and P value 0.740, 0.147 and 0.740 respectively. The results of statistical analysis of gender using chi-square test among the osteoporosis group, the osteopenia group and the normal bone mass group showed that there were statistical differences among the three groups(chi-square value=15.584, P<0.05).2 After making correlation analysis between bone density and the levels of serum TLR-4 in patients with diabetes using the method of linear correlation, the results showed that TTBMD and RTTBMD in people with diabetes had negative correlation with TLR-4( r=-0.251,P=0.018),(r=-0.278,P=0.009), and there was no correlation between LTTBMD and TLR-4. After analyzing the bone density and BMI in patients with diabetes using the method of linear correlation, the results showed that TTBMD and RTTBMD had positive correlation with BMI( r=0.226,P=0.034),(r=0.317,P=0.003), and there was no correlation between LTTBMD and BMI.3 After making correlation analysis between the levels of serum TLR-4 and the age in patients with diabetes using the method of linear correlation, the results showed that there existed positive and negative correlation between age and TLR-4(r=0.395,P=0.000). After making correlation analysis between the levels of serum TLR-4 and BMI in patients with diabetes, the results showed that there was negative correlation between BMI and TLR-4(r=-0.229,P=0.032). After making correlation analysis between the levels of serum TLR-4 in patients with diabetes and the diabetes duration, glycosylated hemoglobin and the levels of blood fat(TC, TG, LDL-C, VLDL), the results showed that there was no obvious correlation between the levels of serum TLR-4 and the diabetes duration, glycosylated hemoglobin and the levels of blood fat(TC,TG,LDL-C,VLDL), with R value 0.119, 0.036,-0.118,-0.097, 0.005 and-0.113 respectively, and P value 0.268,0.736,0.276,0.371,0.963 and 0.296 respectively.4 After making correlation analysis TLR- 4 level and duration in type 2 diabetes bone mass normal group, the bone loss, osteoporosis group Using the curve fitting(Linear, Quadratic and Compound, an Exponential), and the bone mass normal type 2 diabetes mellitus group P values were 0.409, 0.714, 0.474, 0.474;Type 2 diabetes, osteopenia group P values were 0.569, 0.348, 0.482, 0.482;Type 2 diabetic osteoporosis group P values were 0.135, 0.254, 0.189, 0.189. After making correlation analysis TLR- 4 level and duration in type 2 diabetes bone mass normal group, the bone loss, osteoporosis group Using the curve fitting(Linear, Quadratic and Compound, an Exponential), and the bone mass normal type 2 diabetes mellitus group P values were 0.116, 0.179, 0.132, 0.132;Type 2 diabetes, osteopenia group P values were 0.463, 0.686, 0.476, 0.476;Type 2 diabetic osteoporosis group P values were 0.906, 0.942, 0.577, 0.577.5 After multiple regression analysis between bone mineral density(TTBMD RTTBMD LTTBMD) and its influencing factors(age,BMI,age, BMI, course, glycosylated hemoglobin) and the levels of serum TLR-4 in patients with diabetes using stepwise regression method, the independent variables age and BMI into the model, the P values < 0.05, there is statistical significance, the regression equation is Y=4.544 + 0.114 age- 0.251 BMI.Conclusion:1 Type 2 diabetes patients with bone mineral density is affected by gender and age, age of people with type 2 diabetes group is higher than that of osteopenia and osteoporosis bone mass normal group, age of the patients with type 2 diabetes osteopenia group and normal bone have no statistical difference.With BMI, diabetes duration, no clear correlation glycosylated hemoglobin;2 The levels of serum TLR-4 of the osteoporosis group were higher than that of the normal bone mass group and the osteopenia group, and the levels of serum TLR-4 of the osteopenia group were higher than that of the normal bone mass group;3. The levels of serum TLR-4 were affected by age and BMI, having no obvious correlation with diabetes duration, gender, glycosylated hemoglobin and the levels of blood fat.