IADR Abstract Archives
Evaluation of Serum and Renal Calcium and Phosphate Handling in the Prx1- Cre; Klfl/fl Mouse Model
Objectives: Klotho is expressed in variety of tissues including kidneys, bones, parathyroid glands, thymus, and brain. The role of Klotho in the regulation of mineral homeostasis has been extensively studied using kidney specific and global Klotho knock out mouse models. The aim of this study is to investigate renal calcium and phosphate handling of mice lacking Klotho in long bones.
Methods: Serum and Urine samples from 6-week-old male mice with (Klfl/fl) or without Klotho in bone (Prx1- Cre; Klfl/fl) were used to measure calcium, phosphate, and creatinine levels with a standard commercial assay. The urinary excretion of calcium and phosphate were then corrected for creatinine (UrCa/ Cre, UrPi/ Cre) and results were expressed as mean ± SEM. To measure renal gene expression, RNA was extracted from kidneys of control and mutant mice using the standard Trizol protocol. RNA purity was analyzed with the NanodropTM spectrophotometer and only samples with high quality RNA (OD 260/280 ratio of 1.8 or higher) were used for gene expression. Subsequent quantification of expression of target genes was done using the TaqMan® Gene Expression Assays Protocol and the StepOnePlusTM Real-Time PCR System. The expression of target genes was normalized to the expression of the housekeeping gene glyceraldehyde-3-phosphate-dehydrogenase (GAPDH).
Results: We found a statistically significant decrease (p=0.0344) in the urinary phosphate/creatinine level in the Prx1-cre; Kl fl/fl mice compared to KL fl/fl group. There is no statistically significant difference in urinary calcium/ creatinine levels between the experimental and control groups. There was no statistically significant difference in the renal gene expressions of Klotho, 1α-(OH)ase, and 24-(OH)ase between the experimental and the control groups.
Conclusions: Our finding showed that ablation of Klotho in bone results in significant reduction of renal phosphate level, but has no significant effect on renal calcium level. This may indicate that Klotho has an independent activity within the bone that influences the metabolism of phosphate. Given the importance of Klotho in phosphate metabolism, further studies may explore the role of Klotho in dento-alveolar diseases, such as periodontal diseases.
Methods: Serum and Urine samples from 6-week-old male mice with (Klfl/fl) or without Klotho in bone (Prx1- Cre; Klfl/fl) were used to measure calcium, phosphate, and creatinine levels with a standard commercial assay. The urinary excretion of calcium and phosphate were then corrected for creatinine (UrCa/ Cre, UrPi/ Cre) and results were expressed as mean ± SEM. To measure renal gene expression, RNA was extracted from kidneys of control and mutant mice using the standard Trizol protocol. RNA purity was analyzed with the NanodropTM spectrophotometer and only samples with high quality RNA (OD 260/280 ratio of 1.8 or higher) were used for gene expression. Subsequent quantification of expression of target genes was done using the TaqMan® Gene Expression Assays Protocol and the StepOnePlusTM Real-Time PCR System. The expression of target genes was normalized to the expression of the housekeeping gene glyceraldehyde-3-phosphate-dehydrogenase (GAPDH).
Results: We found a statistically significant decrease (p=0.0344) in the urinary phosphate/creatinine level in the Prx1-cre; Kl fl/fl mice compared to KL fl/fl group. There is no statistically significant difference in urinary calcium/ creatinine levels between the experimental and control groups. There was no statistically significant difference in the renal gene expressions of Klotho, 1α-(OH)ase, and 24-(OH)ase between the experimental and the control groups.
Conclusions: Our finding showed that ablation of Klotho in bone results in significant reduction of renal phosphate level, but has no significant effect on renal calcium level. This may indicate that Klotho has an independent activity within the bone that influences the metabolism of phosphate. Given the importance of Klotho in phosphate metabolism, further studies may explore the role of Klotho in dento-alveolar diseases, such as periodontal diseases.