Deficiency in α-Klotho is involved in the pathogenesis of vascular calcification. Since intermedin (IMD)1-53 (a calcitonin/calcitonin gene-related peptide) protects against vascular calcification, we studied whether IMD1-53 inhibits vascular calcification by upregulating α-Klotho. A rat model of chronic kidney disease (CKD) with vascular calcification induced by the 5/6 nephrectomy plus vitamin D3 was used for study. The aortas of rats with CKD showed reduced IMD content but an increase of its receptor, calcitonin receptor-like receptor, and its receptor modifier, receptor activity-modifying protein 3. IMD1-53 treatment reduced vascular calcification. The expression of α-Klotho was greatly decreased in the aortas of rats with CKD but increased in the aortas of IMD1-53-treated rats with CKD. In vitro, IMD1-53 increased α-Klotho protein level in calcified vascular smooth muscle cells. α-Klotho knockdown blocked the inhibitory effect of IMD1-53 on vascular smooth muscle cell calcification and their transformation into osteoblast-like cells. The effect of IMD1-53 to upregulate α-Klotho and inhibit vascular smooth muscle cell calcification was abolished by knockdown of its receptor or its modifier protein, or treatment with the protein kinase A inhibitor H89. Thus, IMD1-53 may attenuate vascular calcification by upregulating α-Klotho via the calcitonin receptor/modifying protein complex and protein kinase A signaling.

Objective: To investigate changes of adiponectin and its receptors (Adipo R) in rats following chronic renal failure. Methods: Male SD rats were randomly divided into two groups: control group and chronic renal failure (CRF) group. The CRF group were gavaged with adenine (300 mg/kg/d) for 4 weeks and the control group with drinking water. All rats were anesthetized at 2nd or 4th week and blood and urine samples were collected for detection of renal function, 24 h urine protein and adiponectin concentration. Renal tissues were also collected for HE staining, immunohistochemistry and RT-PCR screening. Results: Compared with control group, the serum concentrations of urea and creatinine, 24 h urine protein excretion in the CRF group were significantly higher at 2nd week and further increased at 4th week (p50.05). The adiponectin levels in serum and urine in the CRF group were significantly higher than those of control group (p50.01). The renal expressions of Adipo R1 and Adipo R2 in CRF group were also significantly increased compared to control group (p50.01). The increased expressions of Adipo R1 and Adipo R2 were positively related to the adiponectin levels in serum, urine, and 24 h urine protein. Conclusion: The significant changes in expression of adiponectin and its receptors in rat CRF model could be an adaptive response that may provide the basis to understand pathological changes in chronic kidney disease.

This research was to evaluate the effects of regular hemodialysis (HD) on the brain function of patients with end-stage renal disease (ESRD). Resting-state functional magnetic resonance imaging (rs-fMRI) based on improved k-means clustering algorithm (k-means) was proposed to scan the brains of 30 regular dialysis patients with end-stage renal disease (ESRD) (experimental group) and 30 normal volunteers (control group). The proposed algorithm was compared with the traditional k-means algorithm and mean shift algorithm and applied to the magnetic resonance scan of patients with ESRD on long-term regular HD. The results showed that the neuropsychological cognitive function (NSCF) evaluation result of the test group was much better than that of the control group, and the difference was statistically obvious ( P < 0.05 ). The results of blood biochemistry, Digit Symbol Substitution Test (DSST), and Montreal Cognitive Assessment Scale (MoCA) in the test group showed no statistical difference compared with those in the control group. The running time of the improved k-means algorithm was dramatically shorter than that of traditional k-means algorithm, showing statistical difference ( P < 0.05 ). Comparison among the improved and traditional k-means algorithm and mean shift algorithm suggested that the improved k-means algorithm showed a lower error rate for image segmentation, and the differences were statistically remarkable ( P < 0.05 ). In conclusion, the improved k-means algorithm showed better time efficiency and the lowest error rate in processing rs-fMRI images than the traditional k-means algorithm and mean shift algorithm, and the effects of regular HD on the brains of patients with ESRD were evaluated effectively.