Valeriu Atanasiu

Hepcidin – central regulator of iron metabolism

The knowledge about mammalian iron metabolism has advanced dramatically over the past decades. Studies of genetics, biochemistry and molecular biology allowed us the identification and characterization of many of the molecules involved in regulation of iron homeostasis. Important progresses were made after the discovery in 2000 of a small peptide – hepcidin – that has been proved to play a central role in orchestration on iron metabolism also providing a link between iron metabolism and inflammation and innate immunity. Hepcidin directly interacts with ferroportin (FPN), the only known mammalian iron exporter, which is expressed by enterocytes, macrophages and hepatocytes. The direct hepcidin–FPN interaction allows an adaptative response from the body in situations that alter normal iron homeostasis (hypoxia, anemia, iron deficiency, iron overload, and inflammation).

Chelidonium majus – an Integrative Review: Traditional Knowledge versus Modern Findings

Chelidonium majus L. (family Papaveraceae), or greater celandine, is an important plant in western phytotherapy and in traditional Chinese medicine. Crude extracts of C. majus as well as purified compounds derived from it exhibit a broad spectrum of biological activities (antiinflammatory, antimicrobial, antitumoral, analgesic, hepatoprotective) that support some of the traditional uses of C. majus. However, herbal medicine also claims that this plant has several important properties which have not yet been scientifically studied: C. majus is supposed to have diuretic, antitussive and eye-regenerative effects. On the other hand, C. majus also has scientifically proven effects, e.g. anti-osteoporotic activity and radioprotection, which are not mentioned in traditional sources. Moreover, recent controversy about the hepatoprotective versus hepatotoxic effects of Chelidonium majus has renewed the interest of the medical community in this plant. This review is intended to integrate traditional ethno-medical knowledge and modern scientific findings about C. majus in order to promote understanding of its therapeutic actions as well as its toxic potential.

Review article: The role of adipose tissue in uraemia‐related insulin resistance

SUMMARY:  Adipose tissue is no longer considered to be an inert tissue of which function is to store fat. It actively secretes a number of biologic active compounds that are involved in the regulation of many processes like food intake, energy expenditure, metabolism homeostasis, immunity and blood pressure homeostasis. General metabolism alteration in patients with chronic kidney disease has a profound impact on biology of adipocytes. Chronic renal failure is a pathological condition, of which two major hallmarks are chronic inflammation and insulin resistance. In uraemic patients, adipose tissue became an important source of molecules that are responsible, at least in part, for the metabolic disturbances seen in these patients. Some of these molecules act as pro‐inflammatory agents contributing to the maintenance and enhancement of the chronic inflammatory response. These pro‐inflammatory molecules, along with other molecules secreted by the adipose tissue, have a central position in the aetiology of uraemia‐associated insulin resistance. In this review, we intend to summarize some aspects of the biology of adipokines in uraemia, with emphasis on the link between these molecules and insulin resistance.

New alternatives for erythropoietin therapy in chronic renal failure

Erythropoietin (EPO) is one of the main cytokines involved in the regulation of erythropoiesis. The main site of EPO production are the kidneys. An altered EPO production leads to pathological conditions such as anemia and polycythaemia. Due to the progressive loss of renal peritubular cells, patients with chronic kidney disease (CKD) have low EPO plasma levels. This decreases erythron stimulation with the direct consequence of developing anemia. Before the introduction in the clinical practice of rHuEpo, in the late 1980s, the only solution for treating this type of anemia were blood transfusions and anabolic steroids. Even rHuEpo has proven to be safe and effective for treatment of anemias, there are some concerns about its cost, the need for frequent parenteral administration, and development of anti-EPO antibodies. These inconveniences prompted the search for novel erythropoiesis stimulating agents. Different strategies lead to isolation or chemical synthesis of such agents as darbepoetin alfa and EPO mimetics. In this review, we present some general aspects of EPO biology, with emphasis on chronic renal failure, and expose some of the alternatives to EPO used for anemia correction.

Microwave versus electrical oven heating influence on oxidative stress parameters, flavonoids and polyphenols content of five different commercial cooking oils

Consumers are increasingly concerned about the health aspects of food preparation. There is data to support that foods treated with microwaves (MW) develop harmful substances. Vegetable oils are susceptible to lipid peroxidation due to the chemical structure, but also contain antioxidant compounds. Peroxidation products can have harmful effects for human health. The aim of the study was to evaluate the variation of total antioxidant capacity and antioxidant degradation in relation to lipid peroxides formation during conventional and microwave oils heating. Sunflower, corn, soybean, palm and a mixed oil (sunflower, grape, flaxseed and rice oil) were purchased from the local market. To simulate home cooking, different exposure times were tested 5, 10 and 15 min. For all samples, and for each exposure time, Trolox Equivalent Antioxidant Capacity (TEAC), lipid peroxides as thiobarbituric reactive substances (TBARS), conjugated dienes, vitamin E as α-tocopherol, flavonoids and total polyphenols were determined. After 15 minutes heating the best retention for vitamin E was observed for the palm oil (MW 12 mM/l), and corn oil (convection 17 mM/l). The highest total antioxidant capacity after heating belonged to mixed & palm oil (MW 4.6 eq. TROLOX/l) and soybean oil (convection 7.5 mM eq. TROLOX/l). Highest levels of TBARS belonged to the mixed oil (convection 54 uM/l) and soybean oils (MW 83 uM/l). Highest conjugated dienes levels were observed for soybean oil (MW 17 mM/l) and sunflower oil (convection 22 mM/l). The best retention for polyphenols was found in the mixed and sunflower oils (MW and convection 0.80.9 mg/ml. The retention of flavonoid was very small in all oils and the highest amount was found in corn and soybean oil (0.04 mg/ml). During the heating of edible vegetable oils commonly used, total antioxidant capacity along with the amount of vitamin E, flavonoids and polyphenols decreases, while the amount of lipid peroxidation products increases and these processes are more intense when using microwave heating than when using convection heating.

Haemodialysis treatment influence on carbonyl stress parameters

Chronic renal failure is associated with increased oxidative and carbonyl stress. Even if haemodialysis eliminates toxic metabolic products, the procedure per se is associated with further increased oxidative and carbonyl stress in patients with renal disease. The aim of our work was to evaluate the influence of long term haemodialysis treatment on oxidative and carbonyl stress parameters in patients with chronic renal failure. Methods A total of 58 subjects participated in this study: 16 patients with chronic renal insufficiency (CRF) randomly selected from Carol Davila Hospital patients, 20 patients with end stage renal disease undergoing haemodialysis treatment 3 times weekly (HD) and 22 subjects apparently healthy (C) as controls. On blood samples collected after overnight fasting we have determined the concentrations of Amadori Products (AP), total dicarbonilic compounds (DC), malondialdehyde (MDA) and total thiols (SH). Results AP, MDA and DC were significantly increased in patients with chronic renal failure (CRF) while total thiols levels were significantly decreased compared with the controls. Interestingly, for patients undertaking haemodialysis treatment (HD) the AP levels were not significantly increased compared with controls while SH levels were increased. MDA and DC levels were also significantly increased in HD patients compared with the controls. We have not found any significant correlation between AP levels and DC levels in our subjects. Conclusion Haemodialysis treatment is lowering Amadori Products levels in end stage renal disease patients while having no beneficial effect on total dicarbonilic compounds levels. Increased total thiols levels found in HD patients may constitute an activated antioxidant answer to increased oxidative stress