Serum sclerostin in acute kidney injury patients.

BACKGROUND: Many of the mineral metabolite abnormalities encountered in chronic kidney disease (CKD) patients were found also associated with acute kidney injury (AKI). In the last decade, sclerostin was found to intimately affect bone mineral metabolism in CKD patients. Nothing is known about sclerostin in AKI. OBJECTIVE: We looked for serum level of sclerostin in AKI patients in comparison to normal control subjects and if there is an impact on metabolic derangement, endothelial function or clinical outcome. CASES AND METHODS: This is a cross sectional case control observational study of 219 AKI cases (group I) beside 219 age matched normal control subjects (group II). All cases of group I were in the intensive care because of sepsis; 86 had acute on CKD (group Ib), while 133 had de novo AKI (group Ia). All studied subjects underwent estimation of serum sclerostin, parathyroid hormone (PTH), 25 hydroxy vitamin D (25 OH vit D), fibroblast growth factor 23 (FGF23), C-reactive protein (CRP), interleukin 6 (IL6), Homeostatic Model Assessment for Insulin Resistance (Homa IR), beside the routine CBC, kidney and liver function tests, serum calcium, and phosphorus, and flow mediated vasodilation of brachial artery (FMD). Follow-up of group I cases was done till they recovered or passed away. RESULTS: Serum sclerostin, PTH, FGF23, phosphorus, CRP, IL6, HOMA IR, creatinine, urea, uric acid, ALT, AST and white blood cell count (WBC) were significantly higher while serum calcium, 25 OH vit D, hemoglobin, platelet count and FMD were significantly lower in group I compared to group II (P<0.001 in all). On the other hand, there was no significant difference in serum sclerostin, PTH, FGfF23, 25 OH vit D, CRP, IL6, Homa IR and FMD between group Ia and Ib. Survivors were younger in age (median 55.5 vs. 60 years, P<0.04), had lower AST (30.5 vs. 58 units, P<0.001), had higher platelet count (206 vs 162×109/L, P<0.001), otherwise, there was no significant difference in any of the other parameters between survivors and patients that were lost. Serum sclerostin had strong correlation with FGF23 in group I (r=0.99, P<0.001) and group II (r=1, P<0.001). Homa IR had positive correlation with serum sclerostin (r=0.148, P=0.014) and serum FGF23 (r=0.142, P=0.018) in group I. CONCLUSION: Sclerostin is intimately related to FGF23. Sclerostin level increases in AKI patients. Both sclerostin and FGF23 might increase insulin resistance but have no impact on FMD. Neither sclerostin nor FGF23 interfere with AKI outcome.

Impact of hepatitis virus infection on arterial calcification among incident hemodialysis patients.

BACKGROUND: The impact of hepatitis virus infection on arterial calcification (AC) was not studied. OBJECTIVE: To study the prevalence, severity and distribution of AC in incident hemodialysis patients with hepatitis B and C viral infection. CASES AND METHODS: 172 stage 5 CKD adults (98 male and 74 female) were included; 58 of them were seronegative for both hepatitis B and C (SN group), 48 were positive for hepatitis B virus infection (HBV group) and 66 were hepatitis C virus positive (HCV group). Beside histopathology of the obtained arterial samples, all these cases were examined for body mass index (BMI), serum calcium (Ca), phosphorus (P), alkaline phosphatase (AP), serum albumin, uric acid (UA), alanine transaminase (ALT), parathormone (PTH), fibroblast growth factor 23(FGF23), interleukin 6 (IL6), and 25 hydroxy vitamin D (25 (OH) vit D), hemoglobin concentration, and serum ferritin. RESULTS: 86 (50%) of the cases had AC; 11 of them were in SN group (19%), 9 in HBV group (18.8%) and all the 66 HCV group (100%). In SN group, 4 had intimal calcification, 5 had medial calcification, and 2 had both intimal and medial calcification. In HBV group, 9 had intimal calcification, while no cases were encountered with either medial or both site calcifications. In HCV group, 16 had intimal calcification, 31 had medial calcification, and 19 had both intimal and medial calcification. Calcification was in the form of spots in one case in SN group, and 6 cases in HBV group, a single plaque of calcification in 5 cases of SN group, 3 cases of HBV group, and 16 cases of HCV group, multiple plaques were detected in 4 cases in SN group, and 31 cases in HCV group, and diffuse calcification in one case in SN group, and 19 cases in HCV group. In HBV group, calcification was only detected in patients with high viremia, while all patients with low or moderate viremia were devoid of calcification. In HCV group, all patients with low viremia had intimal solitary plaque of calcification, all patients with moderate viremia had multiple plaques of medial calcification, while all patients with high viremia had diffuse intimal and medial calcification. Both groups of viral hepatitis were significantly different in comparison to SN group in either distribution or calcification score (P<0.001 in all). HBV group had significantly lower serum P, CaxP and PTH in comparison to SN group (4.6±0.66 vs. 5.45±0.77mg/dL, 36.4±7.2 vs. 44.1±8.69, and 348±65.4 vs. 405.9±83.2pg/mL, P<0.001, <0.001, and 0.035 respectively). On the other hand, HCV group did not show any significant difference in any of the studied parameters compared to SN group. CONCLUSION: HCV positive patients are more prone to develop AC that is more extensive. HBV positive patients were less likely to have arterial medial calcification, probably related to lower serum phosphorus, CaxP product and PTH. HCV infection should be added as risk factor for AC among CKD patients. Further studies are needed to confirm these findings.

Intraoperative Arterial Biopsy in Incident Hemodialysis Patients: Differences Observed.

INTRODUCTION: Arterial calcification (AC) is a common complication in chronic kidney disease (CKD) patients that starts to develop before these patients need renal replacement therapy. In these patients, calcification can involve tunica intima or tunica media. This study has looked for the prevalence, severity, and distribution of arterial wall calcification in incident hemodialysis patients through intraoperative arterial biopsy obtained during creation of arteriovenous vascular access for hemodialysis. METHODOLOGY: One hundred and seventy-two stage 5 CKD adults (98 male and 74 female) were included. Beside histopathology of the obtained arterial samples, all these cases were tested for serum calcium (Ca), phosphorus (P), alkaline phosphatase, uric acid, parathormone (PTH), fibroblast growth factor 23 (FGF23), and 25 hydroxy vitamin D. RESULTS: Eighty six (50%) of the cases had AC (group I); 29 (17%) as intimal (subgroup Ii), 36 (21%) as medial (subgroup Im), while 21 (12%) had both intimal and medial calcification (subgroup Iim). Eighty-six patients (50%) were devoid of calcification (group II). Apart from the significantly higher serum level of PTH in group I, statistical analysis failed to disclose significant difference in any of the other studied parameters between the 2 groups. On the other hand, there were significant differences in serum P, Ca × P product, serum PTH, and FGF23 between patients according to intensity of calcification. CONCLUSION: Half of incident hemodialysis CKD patients have developed AC mainly in tunica media. Discrepancy in serum P can have an impact on calcification intensity.