Abstract: 【Abstract】Objective To investigate the relationship between serum level of dentin matrix protein 1(DMP1) and the status of mineral metabolism and bone density in maintenance hemodialysis (MHD) patients. Methods A total of 95 MHD patients treated at the Blood Purification Center of Qingdao Municipal Hospital from July 2019 to July 2020 were recruited as the research objects. Their clinical data and laboratory test results were collected, serum DMP1 was determined by ELISA, and femoral neck bone mineral density was assayed by dual-energy X-ray absorptiometry. The influencing factors for serum DMP1 level were evaluated by Spearman correlation analysis and multivariate linear regression, and the influencing factors for low bone mineral density were assessed by binary logistic regression. Results ①Serum DMP1 level was lower in the MHD patients than in the healthy controls (Z=-3.218, P=0.001). ②Spearman correlation analysis showed that DMP1 level was negatively correlated with age and dialysis duration, and positively correlated with eGFR, PTH, and T-score of femoral neck bone mineral density (r=-0.226, -0.223, 0.210, 0.294 and 0.370, respectively; P=0.028, 0.030, 0.041, 0.004 and <0.001, respectively). Multivariate linear regression demonstrated that PTH and T-score of femoral neck bone mineral density were the independent influencing factors for serum
DMP1 level (β=0.211 and 0.399, respectively; P=0.032 and 0.001, respectively). ③Binary logistic regression found that higher serum DMP1 level was an independent protective factor for the lower bone mineral density in MHD patients (OR=0.913, 95% CI 0.845~0.986, P=0.020) after adjusting the confounding factors including age, dialysis age, albumin, alkaline phosphatase and serum calcium. Conclusions Serum DMP1 level in MHD patients is lower than that in healthy controls, and the lower serum level is related to the changes of mineral metabolism and bone density.

Key words: Dentin matrix protein 1, Hemodialysis, Mineral metabolism, Bone mineral density