The Relationship between Serum Sclerostin Levels and Bone Mineral Disorders and Vascular Calcification in Hemodialysis Patients

Background and aim of the study: Sclerostin is produced by osteocytes and has been shown to down-regulate the synthesis of many markers of bone formation by osteogenic cells. The aim of this study to investigate the relationship between serum sclerostin levels and bone mineral disorders and vascular calcification in hemodialysis patients (HD). Methods:This is a cross-sectional study of 70 patients with ESRD on regular HD for at least six months, Theodor Bilharz Research Institute, Giza, Egypt.Twenty-five subjects who matched the ages, genders, and demographics of the study patients were included as a control group.All patients and control groups included in the study underwent a full through history and clinical examination. Serum calcium, phosphorus, alkaline phosphatase and intact PTH (iPTH) levels were measured. Serum sclerostin was measured by an ELISA. Bone Mineral Densitometry Measurements BMD (g/cm2) was determined by dual-energy X-ray absorptiometry (DXA). CT scan was done to detect the presence or absence of vascular calcification and transthoracic echocardiogram to detect the presence or absence of valvular calcification. Results:The mean seumscleostin levels was a statistically significant high in the HD patients when compared with the control group (156.8 ±121.4 Vs.29.38±0.84, p =0.0001 ) and statistically significant high mean ALP in the HD patients when compared with the control group (147.2 ± 94.3 Vs. 38.8 ±23.4, p = 0.0001). The mean BMD was statistically significant low in the HD patients when compared with the controls (0.839±0.086 g/ m2 Vs.1.306 ±0.153 g/ m2, p = 0.0001).The mean seumscleostin levels was statistically significant high in the HD patients with vascular and valvular calcification when compared with HD patients without calcification.Using spearman correlation coefficient analysis, there was statistically significant negative correlations between serum sclerostin levels and iPTH(r=-0.362, p =0.0021), ALP (r=-0.301, p =0.0114), and BMD (r=-0.469, p =0.0278 ), and there was a statistically significant positive correlation between serum sclerostin levels and phosphate(r=0.5829, p =0.0001 ).Independent predictors of BMD in HD patients were determined using multi-variate regression analysis. Sclerostin levels, iPTH, ALP, and age were found to be independent predictors of BMD. Conclusion: High sclerostin levels in patients with ESRD on HD were associated with high risk of vascular and valvularcalcification and were independent predictors of low BMD in such population.

The probability of indicating Osteoprotegrin as a biomarker for osteoporosis in patient with thalassemia major

Background: Osteoporosis is one of the main causes of morbidity in patients with thalassemia major. Osteoprotegerin (OPG) is secreted by osteoblasts and osteogenic stromal stem cells and protects the skeleton from excessive bone reabsorption. In this study, the authors aimed to assess the relationship between OPG with osteoporosis and osteopenia in patients with thalassemia major. Materials and Methods: In this analytic cross-sectional study, 37 patients aged 8-18 years, with thalassemia major were enrolled. Biochemical markers including hemoglobin, ferritin, calcium, phosphorus levels, and MRI T2* heart and liver were assessed. A bone mineral densitometry (BMD) was performed as well. Statistical analysis was performed by the independent T-test and Chi-Square test using the SPSS 20. The Multiple linear regression analysis was used to investigate the association between the BMD Z-score and OPG by the effect modification. Results: The mean age of patients was 14.86±3.72 years. Normal bone density, osteopenia, and osteoporosis were noted in 2 (5.4%), 21 (56.8%), and 14 (37.08%) patients, respectively. The number of girls (P=0.042), mean age (P=0.045), and MRI T2* heart (P=0.033) in patients with osteopenia was significantly higher than patients with osteoporosis. The BMD Z-score was not significantly associated with OPG regarding the total number of participants, whereas in patients with osteoporosis, this association was significant (P=0.001). In all effect modified models, BMD remained statistically non-significant except for body mass index modification (P=0.046). Conclusion: Based on the results, it seems that further complicated studies are needed to be performed on this issue.

Risk factors for residual dizziness in patients successfully treated for unilateral benign posterior semicircular canal paroxysmal positional vertigo

Objective The risk factors for residual dizziness (RD) after successful treatment of benign paroxysmal positional vertigo (BPPV) are poorly characterized. We determined the risk factors for RD in patients with benign unilateral posterior semicircular canal paroxysmal positional vertigo (pc-BPPV) after successful treatment. Methods We conducted a prospective study of patients diagnosed with unilateral pc-BPPV between March 2015 and January 2017. Bone mineral density (BMD) was measured by dual-energy X-ray bone mineral densitometry. Participants underwent bithermal caloric testing (C-test) using videonystagmography and a canalith repositioning procedure (CRP). The occurrence of RD was the primary outcome. The participants underwent follow-up 1 week, 1 month, and 1 year after successful CRP, consisting of outpatient visits, questionnaires, and telephone interviews. Results We assessed 115 participants with unilateral pc-BPPV (31 men and 84 women) who were 53.2 ± 8.8 years old. RD occurred in 60 (52.2%) participants. The participants who experienced RD were older, had vertigo for longer before treatment, and were more likely to show a positive C-test and significant BMD loss. Conclusions We found that a significant reduction in BMD (T-score < −1 standard deviation), a positive C-test, and older age are independently associated with RD in patients with pc-BPPV after successful CRP.

Test–Retest Reproducibility Analysis of Bone Mineral Densitometry Radiomics Features

Background Radiomics features reproducibility assessment is a critical issue in imaging biomarker development era. In the present study, we aimed to assess test–retest reproducibility analysis of bone mineral densitometry (BMD) image radiomics features. Methods In this prospective research work, eighteen patients were included and were subjected to DXA BMD scans acquired within 10 min of each other under an approved protocol. Seven regions of interest (ROIs) including four lumbar spine regions (L1-L4) and three hip regions (trochanteric, inter trochanteric and neck) in both test and re-test images were segmented and 107 radiomics features from seven different feature sets were extracted. Intra-class correlation coefficient (ICC) were initially used to estimate radiomics features reproducibility. Results We showed that there is no radiomics feature with 90% < ICC < 100% in all ROIs, but there are three feature including Strength (from NGTDM feature set), SALGLE (Small Area Low Gray Level Emphasis) (from GLSZM feature set) and Busyness (from NGTDM feature set) with ICC < 70% in all eight ROIs. Shape features has features with ICC < 70%. Conclusion Our study on test–retest reproducibility analysis of bone mineral densitometry radiomics features shows radiomics features have several variations against changes of time of image acquisition. The reproducible features may be used as imaging biomarkers in the field of clinical densitometry. The results of this study may be repeated by more radiomics features and more BMD scanners as first line for bone mineral biomarker discovery.

Bone Mineral Densitometry Reporting: Pearls and Pitfalls

Dual-energy X-ray absorptiometry (DXA) is the method of choice for assessing bone mineral density (BMD). Unfortunately, the performance and interpretation of DXA can be challenging and errors are common. In fact, it has been reported that up to 90% of BMD reports contain at least 1 error. Errors can be the result of technique or interpretative in nature or both and can result in inappropriate diagnosis and management. In this article, we review the various types of pitfalls frequently encountered by physicians interpreting DXA studies. Being aware of these pitfalls will help readers recognize and avoid them when encountered in clinical practice.