Correlation between serum leptin and bone mineral density in hemodialysis patients

Abstract

Introduction: For diagnosing of specific types of bone lesions in hemodialysis (HD) patients, it is necessary to conduct a bone biopsy as the gold standard method. However, it is an invasive procedure. While different markers have been suggested as alternative methods, none of them has been selected. The frequency of hip fractures is 80 fold in HD patients who have two-fold mortality as compared with general population. Objectives: Recently, serum leptin has been suggested as a bone density marker. This study tries to confirm this proposal. Patients and Methods: In this study about 104 HD patients (53.8% male and 46.2% female) were enrolled. The average age was 38.28±7.89 years. Serum leptin, bone alkaline phosphatase, intact parathyroid hormone (iPTH), 25(OH)D, calcium, phosphorus and bone mineral density (BMD) (at the femoral neck and lumbar spine, as measured by dual-energy x-ray absorptiometry [DXA]) were assessed. Results: Analysis by polynomial regression revealed no correlation between BMD Z-score at two points and serum leptin level. According to the thresholds of 25 ng/mL and 18-24 ng/mL in some studies, we detected 25 ng/mL as the threshold in our patients. Under this threshold, the leptin effect on bone mass was negative, and above the threshold of 25 ng/mL, we found leptin had positive effect on bone mass. Conclusion: In this investigation, we found, leptin has a bimodal effect on bone mass. Cortical bones assessment may be a better option for assessment.

Association Between Secondary Hyperparathyroidism and Body Composition in Pediatric Patients With Moderate and Advanced Chronic Kidney Disease

“…Further large-scale studies are needed to confirm these results. The association between serum leptin and SHPT has been explored in adult CKD population but the results are inconsistent among different studies (43), where an inverse (44), positive (45) or absence of correlation (46) between the two laboratory parameters was evocated. Moreover, according to an in-vitro study on differentiated adipocytes from humans with severe SHPT, high PTH levels suppressed adipocyte leptin production via inhibition of Akt signaling, indicating a negative effect of PTH on adipocyte leptin secretion (25).…”

Update on the Crosstalk Between Adipose Tissue and Mineral Balance in General Population and Chronic Kidney Disease

“…In detail, serum leptin was negatively correlated to PTH in three clinical studies including 46, 73, and 161 hemodialysis patients, respectively (25,170,171), confirming the negative impact of secondary hyperparathyroidism on leptin secretion remarked in experimental studies (44,86). However, leptin was positively correlated to circulating PTH levels in a cohort of 978 kidney transplant recipients (78) and 142 patients with CKD stage 2-5 (172), while no correlation was observed in three crosssectional studies of 37, 72, and 107 hemodialysis patients (173)(174)(175). Interestingly, serum adiponectin levels were positively correlated to circulating PTH levels in a large scale crosssectional study, including 716 patients with various CKD stages (176).…”