Contrast-induced acute kidney injury (CI-AKI) is one of the most common causes of AKI in clinical practice. CI-AKI has been found to be strongly associated with morbidity and mortality of the patients. Furthermore, CI-AKI may not be always reversible and it may be associated with the development of chronic kidney disease. Pathophysiology of CI-AKI is not exactly understood and there is no consensus on the preventive strategies. CI-AKI is an active research area thus clinicians should be updated periodically about this topic. In this review, we aimed to discuss the indications of contrast-enhanced imaging, types of contrast media and their impact on nephrotoxicity, major pathophysiological mechanisms, risk factors and preventive strategies of CI-AKI and alternative non-contrast-enhanced imaging methods.

Cholesterol-embolization syndrome (CES) is a multisystemic disease with various clinical manifestations. CES is caused by embolization of cholesterol crystals (CCs) from atherosclerotic plaques located in the major arteries, and is induced mostly iatrogenically by interventional and surgical procedures; however, it may also occur spontaneously. Embolized CCs lead to both ischemic and inflammatory damage to the target organ. Therefore, anti-inflammatory agents, such as corticosteroids and cyclophosphamide, have been investigated as treatment for CES in several studies, with conflicting results. Recent research has revealed that CES is actually a kind of autoinflammatory disease in which inflammasome pathways, such as NLRP3 and IL1, are induced by CCs. These recent findings may have clinical implications such that colchicine and IL1 inhibitors, namely canakinumab, may be beneficial in the early stages of CES.

Endothelial progenitor cells (EPC) are bone marrow derived or tissue-resident cells that play major roles in the maintenance of vascular integrity and repair of endothelial damage. Although EPCs may be capable of directly engrafting and regenerating the endothelium, the most important effects of EPCs seem to be depended on paracrine effects. In recent studies, specific microvesicles and mRNAs have been found to mediate the pro-angiogenic and regenerative effects of EPCs on endothelium. EPC counts have important prognostic implications in cardiovascular diseases (CVD). Uremia and inflammation are associated with lower EPC counts which probably contribute to increased CVD risks in patients with chronic kidney disease. Beneficial effects of the EPC therapies have been shown in studies performed on different models of CVD and kidney diseases such as acute and chronic kidney diseases and glomerulonephritis. However, lack of a clear definition and specific marker of EPCs is the most important problem causing difficulties in interpretation of the results of the studies investigating EPCs.

Background: Disordered mineral metabolism is implicated in the pathogenesis of vascular calcification in hemodialysis (HD) patients. Fibroblast growth factor 23 (FGF-23) is the main regulator of phosphate metabolism. In this prospective study, we aimed to investigate the association of serum FGF-23 with progression of coronary artery calcification in HD patients. Methods: Seventy-four HD patients (36 male/38 female, mean age: 52 ± 14 years) were included. Serum FGF-23 levels were measured by ELISA. Coronary artery calcification score (CACS) was measured twice with one year interval. Patients were grouped as progressive (PG) (36 patients-48%) and non-progressive (NPG). Results: Age, serum phosphorus, baseline and first year CACS were found to be significantly higher in the PG compared to NPG group. Serum FGF-23 levels were significantly higher in PG [155 (80–468) vs 147 (82–234), p = 0.04]. Patients were divided into two groups according to baseline CACS (low group, CACS ≤ 30; high group, CACS > 30). Serum FGF-23 levels were significantly correlated with the progression of CACS (ΔCACS) in the low baseline CACS group (r = 0.51, p = 0.006), but this association was not found in high baseline CACS group (r = 0.11, p = 0.44). In logistic regression analysis for predicting the PG patients; serum FGF-23, phosphorus levels and baseline CACS were retained as significant factors in the model. Conclusions: Serum FGF-23 was found to be related to progression of CACS independent of serum phosphorus levels. FGF-23 may play a major role in the progression of vascular calcification especially at the early stages of calcification process in HD patients.

Alveolar echinococcosis, which is caused by Echinococcus multilocularis, is a very aggressive and potentially fatal infestation which always affects the liver primarily and metastasizes to any part of the body. Imaging studies are usually highly suspicious of carcinoma or sarcoma, and biopsy may provide the first indication of infection. We report a case of disseminated alveolar echinococcosis with liver, lung, and bone involvement mimicking a metastatic malignancy.

Background: Patients with chronic HCV infection have increased liver iron. Recently identified protein hepcidin synthesized in the liver, is thought to be a key regulator for iron homeostasis and is induced by infection and inflammation. Lower erythropoietin and iron supplementation requirements were previously reported in HD patients with HCV infection. We investigated the association of prohepcidin with inflammation and iron parameters in HD patients with and without chronic HCV infection.Methods: Sixty patients (27 male, 33 female, mean age 50 ±15 years) on chronic HD were included. Parameters related to iron metabolism (ferritin, serum iron and total iron binding capacity (TIBC)), inflammation (hs-CRP, TNF-α and IL-6) and prohepcidin levels were measured. The response to treatment (erythropoiesis-stimulating agent (ESA) resistance index) was assessed from the ratio of the weekly erythropoietin (rhuEPO) dose to hemoglobin (Hb) per unit weight.Results: Serum prohepcidin levels of HCV positive patients (135 ± 25 ng/mL) were significantly lower than HCV negative patients [148 ± 18 ng/mL, (p = 0.025)]. Serum IL-6 levels of HCV positive patients were also significantly lower than HCV negative patients (p = 0.016). Serum prohepcidin levels were positively correlated with ferritin (r = 0.405, p = 0.001) and IL-6 (r = 0.271, p = 0.050) levels in HD patients. In the HCV positive group, serum prohepcidin levels significantly correlated with ferritin levels (r = 0.514 p = 0.004). In the HCV negative group, serum prohepcidin levels significantly correlated with serum IL-6 levels (r = 0.418, p = 0.027). In multiple regression analysis performed to predict prohepcidin in HCV positive patients, serum ferritin was found to be an independent variable (r = 0.28, p = 0.008).Conclusions: HCV positive HD patients have low levels of serum prohepcidin and IL-6 which might account for iron accumulation together with lower iron and rhuEPO requirements in these patients.