Background and Objectives: Iron is an essential element that plays a vital role in a wide variety of cellular processes. But when present in excess concentration in organs, it may increase the risk for liver disease, heart failure, and diabetes. Recently, siderophores, which are iron-chelating agents produced by microorganisms, have attracted tremendous attention because of their strong binding and high selectivity to the ferric form of iron. Thus, the use of siderophore in sequestering excess iron in the body as a form of therapy is very attractive. This study determined the effects of commercially available siderophore in sequestering excess iron in organs such as liver, heart, and pancreas under excess iron conditions. Methodology: First, iron-overload was induced by injecting iron dextran (20 mg) into male ICR mice for three consecutive days. The effects of iron to the liver, heart, and pancreas and the possible sequestration by siderophore were determined by scoring histological sections. The liver iron concentration was also assessed by atomic absorption spectroscopy (AAS). Results and Conclusion The study showed that iron-overloaded mice exhibited skin hyperpigmentation and hemosiderosis in liver, heart, and pancreas. Significant changes in the liver include hepatomegaly and development of tumor. Iron-overloaded mice had 2,935% increase in liver iron content compared to the salinetreated mice. However, when iron-overloaded mice were treated with either 100 µg or 200 µg siderophore, there was a 77% and 84% decrease in liver iron content, respectively. Moreover, the treatment of ironoverloaded mice with siderophore prevented the development of hemosiderosis, tumor, and structural changes in the tissues studied. The results showed that siderophore can effectively reduce excess iron and organ damage in iron-overloaded mice and can be potentially employed in chelation therapy of iron-overload diseases. Further studies on the possible mechanisms of siderophore aside from decreasing iron excess and lowering organ dysfunction are recommended.
Siderophores ; Iron Overload ; Iron Chelating Agents ; Hemosiderosis ; Hepatomegaly

The rapid increase in the prevalence of metabolic syndrome, which is associated with a state of elevated systemic oxidative stress and inflammation, is expected to cause future increases in the prevalence of diabetes and cardiovascular diseases. Oxidation of polyunsaturated fatty acids and sugars produces reactive carbonyl species, which, due to their electrophilic nature, react with the nucleophilic sites of certain amino acids. This leads to formation of protein adducts such as advanced glycoxidation/lipoxidation end products (AGEs/ALEs), resulting in cellular dysfunction. Therefore, an effective reactive carbonyl species and AGEs/ALEs sequestering agent may be able to prevent such cellular dysfunction. There is accumulating evidence that histidine containing dipeptides such as carnosine (beta-alanyl-L-histidine) and anserine (beta-alanyl-methyl-L-histidine) detoxify cytotoxic reactive carbonyls by forming unreactive adducts and are able to reverse glycated protein. In this review, 1) reaction mechanism of oxidative stress and certain chronic diseases, 2) interrelation between oxidative stress and inflammation, 3) effective reactive carbonyl species and AGEs/ALEs sequestering actions of histidine-dipeptides and their metabolism, 4) effects of carnosinase encoding gene on the effectiveness of histidine-dipeptides, and 5) protective effects of histidine-dipeptides against progression of metabolic syndrome are discussed. Overall, this review highlights the potential beneficial effects of histidine-dipeptides against metabolic syndrome. Randomized controlled human studies may provide essential information regarding whether histidine-dipeptides attenuate metabolic syndrome in humans.
Amino Acids ; Anserine ; Carbohydrates ; Cardiovascular Diseases ; Carnosine ; Chronic Disease ; Dipeptides ; Fatty Acids, Unsaturated ; Histidine ; Humans ; Inflammation ; Metabolism ; Oxidative Stress ; Prevalence ; Sequestering Agents

OBJECTIVES: Chitosan has been widely investigated and used. However, the literature does not refer to the shelf life of this solution. This study evaluated, through the colorimetric titration technique and an analysis of dentin micro-hardness, the shelf life of 0.2% chitosan solution. MATERIALS AND METHODS: Thirty human canines were sectioned, and specimens were obtained from the second and third slices, from cemento-enamel junction to the apex. A 0.2% chitosan solution was prepared and distributed in 3 identical glass bottles (v1, v2, and v3) and 3 plastic bottles (p1, p2, and p3). At 0, 7, 15, 30, 45, 60, 90, 120, 150, and 180 days, the specimens were immersed in each solution for 5 minutes (n = 3 each). The chelating effect of the solution was assessed by micro-hardness and colorimetric analysis of the dentin specimens. 17% EDTA and distilled water were used as controls. Data were analyzed statistically by two-way and Tukey-Kramer multiple comparison (α = 0.05). RESULTS: There was no statistically significant difference among the solutions with respect to the study time (p = 0.113) and micro-hardness/time interaction (p = 0.329). Chitosan solutions and EDTA reduced the micro-hardness in a similar manner and differed significantly from the control group (p < 0.001). Chitosan solutions chelated calcium ions throughout the entire experiment. CONCLUSIONS: Regardless of the storage form, chitosan demonstrates a chelating property for a minimum period of 6 months.
Calcium ; Chelating Agents ; Chitosan* ; Colorimetry* ; Dentin* ; Edetic Acid ; Glass ; Humans ; Ions ; Plastics ; Product Packaging* ; Water

PURPOSE: Transient hypoxia is an initial event that accentuates ischemia/reperfusion (I/R) injury in the liver. Hepatic ischemia/reperfusion (I/R) injury is largely related to innate immunity via Toll-like receptor 4 (TLR4) signaling. However, the mechanism by which hypoxia could lead to activate TLR4 signaling remains unclear. Therefore, the aim of this experimental study investigates how TLR4 signalling is activated by hypoxia. METHODS: Hepatocytes were isolated from male wild-type (C57BL/6) mice (8~12 weeks old) by an in situ collagenase (Type IV, Sigma-Aldrich) perfusion technique. In this study, using primary mouse hepatocytes in culture to 1% oxygen, detection of TLR4 translocation to the lipid rafts on the cell membrane by immunofluorescence staining and immunoblotting was saught. RESULTS: Hypoxia caused TLR4/MD2 and beta2-Integrin (CD11b/CD18) translocation to lipid rafts associated with CD14 in hepatocytes. The cholesterol sequestering agent, Nystatin and Filipin prevented hypoxia-induced TLR4/MD2 translocation to lipid rafts. Consistent with a role for oxidative stress in this effect, in vitro H2O2 treatment of hepatocytes similarly caused TLR4/MD2 translocation to lipid rafts. In addition, translocation of hypoxia-induced TLR4 complex was inhibited by N-acetylcysteine (NAC) demonstrating that the activation of TLR4 signaling is dependent on ROS. Further, the cholesterol sequestering agent, nystatin, prevented hypoxia-induced high mobility group box 1 (HMGB1) release in hepatocytes. CONCLUSION: These results suggest that ROS dependent TLR4 signaling is achieved following receptor translocation to the lipid raft in hepatocytes. We hypothesized that this mechanism is required for the release of HMGB1, an early mediator of injury and inflammation in hepatic I/R injury.
Acetylcysteine ; Animals ; Anoxia* ; Cell Membrane ; Cholesterol ; Cluster Analysis* ; Collagenases ; Filipin ; Fluorescent Antibody Technique ; Hepatocytes* ; HMGB1 Protein ; Humans ; Immunity, Innate ; Immunoblotting ; Inflammation ; Liver ; Male ; Mice* ; Nystatin ; Oxidative Stress ; Oxygen ; Perfusion ; Sequestering Agents ; Toll-Like Receptor 4*

A previous report by this laboratory demonstrated that bacterial iron chelator (siderophore) triggers inflammatory signals, including the production of CXC chemokine IL-8, in human intestinal epithelial cells (IECs). Microarray-based gene expression profiling revealed that iron chelator also induces macrophage inflammatory protein 3 alpha (MIP-3alpha)/ CC chemokine-ligand 20 (CCL20). As CCL20 is chemotactic for the cells involved in host adaptive immunity, this suggests that iron chelator may stimulate IECs to have the capacity to link mucosal innate and adaptive immunity. The basal medium from iron chelator deferoxamine (DFO)-treated HT-29 monolayers was as chemotactic as recombinant human CCL20 at equivalent concentrations to attract CCR6+ cells. The increase of CCL20 protein secretion appeared to correspond to that of CCL20 mRNA levels, as determined by real-time quantitative RT-PCR. The efficacy of DFO at inducing CCL20 mRNA was also observed in human PBMCs and in THP-1 cells, but not in human umbilical vein endothelial cells. Interestingly, unlike other proinflammatory cytokines, such as TNF-alpha and IL-1beta, a time-dependent experiment revealed that DFO slowly induces CCL20, suggesting a novel mechanism of action. A pharmacologic study also revealed that multiple signaling pathways are differentially involved in CCL20 production by DFO, while some of those pathways are not involved in TNF-alpha-induced CCL20 production. Collectively, these results demonstrate that, in addition to some bacterial products known to induce host adaptive immune responses, direct chelation of host iron by infected bacteria may also contribute to the initiation of host adaptive immunity in the intestinal mucosa.
Calcium/metabolism ; Cell Movement/drug effects ; Chemokines, CC/genetics/*metabolism ; Deferoxamine/*pharmacology ; Egtazic Acid/analogs & derivatives/pharmacology ; HT29 Cells ; Humans ; Immunity, Mucosal/*drug effects ; Intestinal Mucosa/*drug effects/immunology/metabolism ; Iron Chelating Agents/*pharmacology ; Macrophage Inflammatory Proteins/genetics/*metabolism ; NF-kappa B/metabolism ; Phosphoprotein Phosphatase/physiology ; Protein Transport/drug effects ; Protein-Serine-Threonine Kinases/physiology ; RNA, Messenger/genetics/metabolism ; Receptors, Chemokine/metabolism ; Research Support, Non-U.S. Gov't

Melittin, a major component of bee venom, produces a sustained decrease in mechanical threshold, and an increase in spontaneous flinchings and paw thickness, which are characteristics similar to those induced by whole bee venom. Melittin-induced nociception has been known to be modulated by the changes in the activity of excitatory amino acid receptors, voltage-dependent calcium channels, cyclooxygenase and serotonin receptors. The present study was undertaken to investigate the role of calcium chelators (TMB-8 & Quin 2) in melittin-induced nociceptive responses. Changes of mechanical threshold and spontaneous flinching behaviors were measured at a given time point following intraplantar injection of melittin (30microgram/paw). Intrathecal or intraplantar pre-administration and intrathecal post-treatment of TMB-8 and Quin 2 significantly prevented the melittin-induced reduction of mechanical threshold, and intraplantar or intrathecal pre-treatment of TMB-8 and Quin 2 suppressed melittin-induced flinching behaviors. These results indicate that calcium ion in the spinal dorsal horn neurons and peripheral nerves plays an important role in the production and maintenance of mechanical allodynia and spontaneous pain by melittin.
Animals ; Bee Venoms ; Calcium Channels ; Calcium* ; Chelating Agents ; Hyperalgesia ; Ions* ; Melitten ; Nociception* ; Peripheral Nerves ; Posterior Horn Cells ; Prostaglandin-Endoperoxide Synthases ; Rats* ; Receptors, Glutamate ; Receptors, Serotonin

Deferasirox is a new oral iron chelator. It is the first oral iron chelator approved in USA by FDA for transfusion-dependent patients above 2 years suffering from severe chronic iron overload. It is also recommended as the initial therapy for patients over the age of 6 years who are suffering from beta-thalassaemia. The clinical study is developing in China. This review focuses the related studies and the latest progression about deferasirox. The phase II and III clinical trials and pharmacokinetics indicated that deferasirox is a safety and effective oral iron chelator, can significantly decrease the myocardial and hepatic iron load, also is easy to accept for patients. The common adverse reactions are gastrointestinal symptom and rash. But it was recently reported that deferasirox has some rare adverse events to which we must attach importance, especially for the special people. Besides the patients with chronic iron overload resulting from blood transfusions (transfusional hemosiderosis), the drug is also used for the patients who has accepted auto-SCT or suffered from reversible renal inadequacy caused by Fanconi syndrome. The standard dosage is not useful to every patient. The clinician should adjust dosage based on the patient's condition and related indexes. The serum ferritin is not one and reliable index to monitoring the effect and adjust the dosage. Otherwise, this review recommends some new characters of deferasirox, e.g. anti-fungus, anti-cell proliferation and so on.
Benzoates ; administration & dosage ; Clinical Trials as Topic ; Humans ; Iron Chelating Agents ; administration & dosage ; Triazoles ; administration & dosage

We report two cases of band keratopathy who were treated with thick amniotic membrane that contained a basement membrane structure as a graft, after ethylenediaminetetraacetic acid chelation with trephination and blunt superficial lamellar keratectomy in the anterior stroma. In each case, basement membrane was destroyed and calcium plaque invaded into anterior stroma beneath Bowman's membrane. The calcified lesions were removed surgically, resulting in a smooth ocular surface, and the fine structures of band keratopathy were confirmed by pathologic findings. After that, amniotic membrane transplantation was performed to replace the excised epithelium and stroma. Wound healing was completed within 10 days. Stable ocular surface was restored without pain or inflammation. During the mean follow-up period of 13.5 months, no recurrence of band keratopathy was observed. This combined treatment is a safe and effective method for the removal of deep-situated calcium plaque and allowing the recovery of a stable ocular surface.
Amnion/*anatomy & histology/*transplantation ; Calcium/metabolism ; Chelating Agents/*therapeutic use ; Cornea/pathology/surgery ; Corneal Diseases/*drug therapy/pathology/*surgery ; Edetic Acid/*therapeutic use ; Female ; Humans ; Male ; Middle Aged

BACKGROUNDCalcium and phosphorus metabolic disturbance are common in dialysis patients and associated with increased morbidity and mortality. Therefore, maintaining the balance of calcium and phosphate metabolism and suitable intact parathyroid hormone (iPTH) level has become the focus of attention. We investigated the effects of different peritoneal dialysate calcium concentrations on calcium phosphate metabolism and iPTH in continuous ambulatory peritoneal dialysis (CAPD) patients.

METHODSForty stable CAPD patients with normal serum calcium were followed for six months of treatment with 1.25 mmol/L calcium dialysate (DCa1.25, PD4, 22 patients) or a combination of 1.75 mmol/L calcium dialysate (DCa1.75, PD2) and PD4 (18 patients) twice a day respectively. Total serum calcium (after albumin correction), serum phosphorus, iPTH, alkaline phosphatase (ALP) and blood pressure were recorded before and 1, 3 and 6 months after treatment commenced.

RESULTSNo significant difference was found in baseline serum calcium, phosphorus between the two patient groups, but the levels of iPTH were significantly different. No significant changes were found in the dosage of calcium carbonate and active vitamin D during 6 months. In the PD4 group, serum calcium level at the 1st, 3rd, 6th months were significantly lower than the baseline (P < 0.05). There was no significant difference in serum phosphorus after 6 months treatment. iPTH was significantly higher (P < 0.001) at the 1st, 3rd, and 6th months compared with the baseline. No differences were seen in ALP and blood pressure. In the PD4+PD2 group, no significant changes in serum calcium, phosphorus, iPTH, ALP and BP during the 6-month follow-up period.

CONCLUSIONSTreatment with 1.25 mmol/L calcium dialysate for six months can decrease serum calcium, increase iPTH, without change in serum phosphorus, ALP, and BP. The combining of PD4 and PD2 can stabilize the serum calcium and avoid fluctuations in iPTH levels.

Aged ; Alkaline Phosphatase ; metabolism ; Blood Pressure ; physiology ; Calcium ; metabolism ; Chelating Agents ; Female ; Humans ; Male ; Middle Aged ; Peritoneal Dialysis ; methods ; Phosphorus ; metabolism ; Retrospective Studies

AIMTo study the effects of sodium magnesium fructose diphosphate (SMFD) on free calcium concentration and nitric oxide synthase activity of ischemic synaptosome, so as to explore the protective mechanisms of SMFD on cerebral ischemia.

METHODSThe synaptosomes from normal rat brain were prepared by phase partition and cultured with oxygen-glucose deprivation to establish ischemic synaptosome model. The intrasynaptosomal free calcium concentration and nitric oxide synthase activity were detected separately after the synaptosomes were co-incubated with SMFD (1.3 mmol.L-1) or fructose-1, 6-diphosphate (FDP, 4.0 mmol.L-1) for 60 min.

RESULTSSMFD decreased the free calcium concentration and reduced the activity of nitric oxide synthase (NOS) of ischemic synaptosomes. Its effects were more powerful than those of FDP.

CONCLUSIONSMFD may protect neurons from ischemic injury by preventing intracellular Ca2+ overload and inhibiting the activity of nitric oxide synthase.

Animals ; Brain Ischemia ; enzymology ; metabolism ; Calcium ; metabolism ; Chelating Agents ; pharmacology ; Fructosediphosphates ; pharmacology ; Magnesium ; chemistry ; Male ; Nitric Oxide Synthase ; drug effects ; metabolism ; Rats ; Rats, Wistar ; Sodium ; chemistry ; Synaptosomes ; metabolism