Raised haematocrit concentration and the risk of death and vascular complications after major surgery.

BACKGROUND: Preoperative anaemia is associated with adverse postoperative outcomes. Data on raised preoperative haematocrit concentration are limited. This study aimed to evaluate the effect of raised haematocrit on 30-day postoperative mortality and vascular events in patients undergoing major surgery. METHODS: This was a cohort study using the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database. Thirty-day mortality and vascular events, demographics and perioperative risk factors were obtained for adults undergoing major surgery. The adjusted effect of raised (over 0·50) compared with normal (0·41-0·50, American Medical Association reference range) preoperative haematocrit concentration on postoperative outcomes was assessed. Separate sex-specific analyses were also conducted, using haematocrit concentration thresholds commonly used in the diagnosis and management of apparent or absolute erythrocytosis. RESULTS: Some 3961 (2·0 per cent) of 197 469 patients had a raised haematocrit concentration before surgery. After adjustment, the 30-day postoperative mortality rate was higher in patients with raised haematocrit than in those without (odds ratio (OR) 2·23, 95 per cent confidence interval 1·77 to 2·80). Thirty-day rates of deep vein thrombosis (OR 1·95, 1·44 to 2·64) and pulmonary embolism (OR 1·79, 1·17 to 2·73), but not myocardial infarction or stroke, were also higher in patients with a raised haematocrit concentration. The effect on mortality was noted beyond the haematocrit thresholds of 0·48 in women and 0·52 in men; the effect estimates were considerably higher for values exceeding 0·54. Values between 0·41 and 0·45 were not associated with increased mortality risk. Similar observations were noted for venous thrombosis, although with apparent sex differences. CONCLUSION: A raised haematocrit concentration was associated with an increased risk of 30-day mortality and venous thrombosis following major surgery.

Efficacy and safety of deferasirox at low and high iron burdens: results from the EPIC magnetic resonance imaging substudy.

The effect of deferasirox dosing tailored for iron burden and iron loading based on liver iron concentration (LIC) was assessed over 1 year in less versus more heavily iron-overloaded patients in a substudy of the Evaluation of Patients' Iron Chelation with Exjade®. Deferasirox starting dose was 10-30 mg/kg/day, depending on blood transfusion frequency, with recommended dose adjustments every 3 months. Therapeutic goals were LIC maintenance or reduction in patients with baseline LIC <7 or ≥7 mg Fe/g dry weight (dw), respectively. Changes in LIC (R2-magnetic resonance imaging) and serum ferritin after 1 year were assessed. Adverse events (AEs) and laboratory parameters were monitored throughout. Of 374 patients, 71 and 303 had baseline LIC <7 and ≥7 mg Fe/g dw, respectively; mean deferasirox doses were 20.7 and 27.1 mg/kg/day (overall average time to dose increase, 24 weeks). At 1 year, mean LIC and median serum ferritin levels were maintained in the low-iron cohort (-0.02 ± 2.4 mg Fe/g dw, -57 ng/mL; P = not significant) and significantly decreased in the high-iron cohort (-6.1 ± 9.1 mg Fe/g dw, -830 ng/mL; P < 0.0001). Drug-related gastrointestinal AEs, mostly mild to moderate, were more frequently reported in the <7 versus ≥7 mg Fe/g dw cohort (39.4 versus 20.8 %; P = 0.001) and were not confounded by diagnosis, dosing, ethnicity, or hepatitis B and/or C history. Reported serum creatinine increases did not increase in low- versus high-iron cohort patients. Deferasirox doses of 20 mg/kg/day maintained LIC <7 mg Fe/g dw and doses of 30 mg/kg/day were required for net iron reduction in the high-iron cohort, with clinically manageable safety profiles. The higher incidence of gastrointestinal AEs at lower iron burdens requires further investigation.

Reversal of cardiac iron loading and dysfunction in thalassemic mice by curcuminoids.

Non-transferrin bound iron (NTBI) is found in plasma of ß-thalassemia patients and causes oxidative tissue damage. Cardiac siderosis and complications are the secondary cause of death in ß-thalassemia major patients. Desferrioxamine (DFO), deferiprone (DFP) and deferasirox (DFX) are promising chelators used to get negative iron balance and improve life quality. DFP has been shown to remove myocardial iron effectively. Curcuminoids (CUR) can chelate plasma NTBI, inhibit lipid peroxidation and alleviate cardiac autonomic imbalance. Effects of CUR on cardiac iron deposition and function were investigated in iron-loaded mice. Wild type ((mu)ß(+/+) WT) and heterozygous ß-knockout ((mu)ß(th-3/+) BKO) mice (C57BL/6) were fed with ferrocene-supplemented diet (Fe diet) and coincidently intervened with CUR and DFP for 2 months. Concentrations of plasma NTBI and malondialdehyde (MDA) were measured using HPLC techniques. Heart iron concentration was determined based on atomic absorption spectrophotometry and Perl's staining methods. Short-term electrocardiogram (ECG) was recorded with AD Instruments Power Lab, and heart rate variability (HRV) was evaluated using MATLAB 7.0 program. Fe diet increased levels of NTBI and MDA in plasma, nonheme iron and iron deposit in heart tissue significantly, and depressed the HRV, which the levels were higher in the BKO mice than the WT mice. CUR and DFP treatments lowered plasma NTBI as well as MDA concentrations (p <0.05), heart iron accumulation effectively, and also improved the HRV in the treated mice. The results imply that CUR would be effective in decreasing plasma NTBI and myocardial iron, alleviating lipid peroxidation and improving cardiac function in iron-loaded thalassemic mice.

Effects of green tea on iron accumulation and oxidative stress in livers of iron-challenged thalassemic mice.

Liver is affected by secondary iron overload in transfusions dependent b-thalassemia patients. The redox iron can generate reactive oxidants that damage biomolecules, leading to liver fibrosis and cirrhosis. Iron chelators are used to treat thalassemias to achieve negative iron balance and relieve oxidant-induced organ dysfunctions. Green tea (GT) (Camellia sinensis) catechins exhibit anti-oxidation, the inhibition of carcinogenesis, the detoxification of CYP2E1-catalyzed HepG2 cells and iron chelation. The purpose of this study was to investigate the effectiveness of GT in iron-challenged thalassemic mice. Heterozygous BKO type-thalassemia (BKO) mice (C57BL/6) experienced induced iron overload by being fed a ferrocene-supplemented diet (Fe diet) for 8 weeks, and by orally being given GT extract (300 mg/kg) and deferiprone (DFP) (50 mg/kg) for a further 8 weeks. Liver iron content (LIC) was analyzed by TPTZ colorimetric and Perl's staining techniques. Concentrations of liver reduced glutathione (GSH), collagen and malondialdehyde (MDA) were also measured. Dosages of the GT extract and DFP lowered LIC in the Fe diet-fed BKO mice effectively. The extract did not change any concentrations of liver glutathione, collagen and MDA in the BKO mice. Histochemical examination showed leukocyte infiltration in the near by hepatic portal vein and high iron accumulation in the livers of the iron-loaded BKO mice, however GT treatment lowered the elevated iron deposition. In conclusion, green tea inhibits or delays the deposition of hepatic iron in regularly iron-loaded thalassemic mice effectively. This will prevent the iron-induced generation of free radicals via Haber-Weiss and Fenton reactions, and consequently liver damage and fibrosis. Combined chelation with green tea would be investigated in beta-thalassemia patients with iron overload.

Efficacy of curcuminoids in alleviation of iron overload and lipid peroxidation in thalassemic mice.

Non-transferrin bound iron (NTBI) is detectable in plasma of beta-thalassemia patients and participates in free-radical formation and oxidative tissue damage. Desferrioxamine (DFO), deferiprone (DFP) and deferasirox (DFX) are iron chelators used for treatment of iron overload; however they may cause adverse effects. Curcuminoids (CUR) exhibits many pharmacological activities and presents beta-diketone group to bind metal ions. Iron-chelating capacity of CUR was investigated in thalassemic mice. The mice (C57BL/6 stain); wild type ((mu)beta(+/+)) and heterozygous beta-knockout ((mu)beta(th-3/+)) were fed with ferrocene-supplemented diet for 2 months, and coincidently intervened with CUR (200 mg/kg/day) and DFP (50 mg/kg/day). Plasma NTBI was quantified using NTA chelation/HPLC method, and MDA concentration was analyzed by TBARS-based HPLC. Hepatic iron content (HIC) and total glutathione concentration were measured colorimetrically. Tissue iron accumulation was determined by Perl's staining. Ferrocene-supplemented diet induced occurrence of NTBI in plasma of thalassemic mice as well as markedly increased iron deposition in spleen and liver. Treatment with CUR and DFP decreased levels of the NTBI and MDA effectively. Hepatic MDA and nonheme iron content was also decreased in liver of the treated mice whilst total glutathione levels were increased. Importantly, the CUR and DFP reduced liver weight index and iron accumulation. Clearly, CUR is effective in chelation of plasma NTBI in iron-loaded thalassemic mice. Consequently, it can alleviate iron toxicity and harmfulness of free radicals. In prospective, efficacy of curcumin in removal of labile iron pool (LIP) in hepatocytes and cardiomyocytes are essential for investigation.

Effect of green tea on iron status and oxidative stress in iron-loaded rats.

Plasma non-transferrin bound iron (NTBI) is potentially toxic and contributes to the generation of reactive oxygen species (ROS), consequently leading to tissue damage and organ dysfunction. Iron chelators and antioxidants are used for treatment of thalassemia patients. Green tea (GT) contains catechins derivatives that have many biological activities. The purpose of this study was to investigate the iron-chelating and free-radical scavenging capacities of green tea extract in vivo. Rats were injected ip with ferric citrate together with orally administered GT extract (GTE) for 4 months. Blood was collected monthly for measurement of iron overload and oxidative stress indicators. Plasma iron (PI) and total iron-binding capacity (TIBC) were quantified using bathophenanthroline method. Plasma NTBI was assayed with NTA chelation/HPLC. Plasma malonyldialdehyde (MDA) was determined by using the TBARS method. Erythrocyte oxidative stress was assessed using flow cytometry. Levels of PI, TIBC, NTBI and MDA, and erythrocyte ROS increased in the iron-loaded rats. Intervention with GT extract markedly decreased the PI and TIBC concentrations. It also lowered the transferrin saturation and effectively inhibited formation of NTBI. It also decreased the levels of erythrocyte ROS in week 4, 12 and 16. Therefore, green tea extract can decrease iron in plasma as well as eliminate lipid peroxidation in plasma, and destroy formation of erythrocyte ROS in the rats challenged with iron. The bifunctional effects could be beneficial in alleviating the iron and oxidative stress toxicity. In prospective, these GTE activities should be further examined in thalassemic animals or humans.

Curcumin contributes to in vitro removal of non-transferrin bound iron by deferiprone and desferrioxamine in thalassemic plasma.

Non-transferrin-bound iron (NTBI) is detectable in plasma of beta-thalassemia patients with transfusional iron overload. This form of iron may cause oxidative tissue damage and increased iron uptake, into several vital organs. Removal of NTBI species is incomplete and transient using standard intermittent desferrioxamine (DFO) or deferiprone (DFP) monotherapy. Combinations of these or other chelators may improve the protection time from NTBI and increase removal of harmful NTBI species. Curcuminoids from Curcuma longa L. is a naturally occurring phytochemical which shows a wide range of pharmacological properties including anti-oxidative, anti-inflammatory, anti-cancer and iron-chelating activities. In this study, the curcuminoids was investigated for NTBI chelation in thalassemic plasma in vitro and for the potential to improve NTBI removal when used with other chelators. Curcumin bound Fe(3+) to form a Fe(3+)-curcumin complex with a predominant absorption at 500 nm. The chemical binding of curcumin was dose- and time-dependent and more specific for Fe(3+) than Fe(2+). Using a HPLC-based NTBI assay without an aluminium blocking step, curcumin shuttled the iron from Fe(3+)-NTA complex, giving underestimated NTBI values. At equivalent concentrations DFO, DFP and curcumin decreased plasma NTBI with the order of DFP>DFO>curcumin. None of these chelators removed NTBI completely, but curcumin appeared to increase the rate of NTBI removal when added to DFP. It is proposed that the beta-diketo moiety of curcumin participates in the NTBI chelation.

Epigallocatechin-3-gallate and epicatechin-3-gallate from green tea decrease plasma non-transferrin bound iron and erythrocyte oxidative stress.

Beta-thalassemia patients suffer from secondary iron overload caused by increased iron absorption and multiple blood transfusions. Excessive iron catalyzes free-radical formation, causing oxidative tissue damage. Non-transferrin bound iron (NTBI) detected in thalassemic plasma is highly toxic and chelatable. Desferrioxamine and deferiprone are used to treat the iron overload, but many side effects are found. Epigallocatechin gallate (EGCG) and epicatechin gallate (ECG) in green tea (GT) show strong antioxidant properties. We separated the EGCG and ECG from GT extract using an HPLC, and examined their iron-binding and free-radical scavenging activities. They bound Fe(3+) rapidly to form a complex with a predominant absorption at 560 nm. EGCG and ECG bound chemical Fe(3+) and chelated the NTBI in a time- and dose dependent manner. They also decreased oxidative stress in iron-treated erythrocytes. In conclusion, EGCG and ECG could be natural iron chelators that efficiently decrease the levels of NTBI and free radicals in iron overload.

Recent insights into interactions of deferoxamine with cellular and plasma iron pools: Implications for clinical use.

Despite the availability of deferoxamine (DFO) for more than three decades, its rates of interaction with cellular iron pools in different tissues, and the effects of its pharmacokinetics on the interaction with plasma iron pools, remain incompletely understood. The positive charge of DFO, together with the negative resting potential in vertebrate cells, favors cellular uptake, whereas the low lipophilicity and high molecular weight counter this effect. The findings presented suggest a facilitated uptake of DFO into hepatocytes, being several hundred-fold faster than into red cells. Antibodies that selectively recognize ferrioxamine (FO) show that initial hepatocellular iron chelation is cytosolic, but later transposes to lysosomal and ultimately canalicular compartments. Strong FO staining is visible in myocytes within 4-8 h after commencing a subcutaneous DFO infusion, indicating effective chelation of myocyte iron. A methodology was developed to study the interaction of DFO and its metabolites with plasma iron pools by stabilizing DFO with aluminum ions, thereby preventing iron shuttling from non-transferrin-bound iron (NTBI) onto DFO after plasma collection. DFO removes only about a third of NTBI rapidly, and NTBI is rarely cleared completely. Increasing DFO dosing does not increase NTBI removal, but instead leads to a greater rebound in NTBI on cessation of intravenous infusion. Thus, intermittent infusions of high-dose DFO are less desirable than continuous infusions at low doses, particularly in high-risk patients. Here the benefits of continuous DFO on heart function occur before changes in T2*-visible storage iron, consistent with early removal of a toxic labile iron pool within myocytes.

A retrospective observational study of pre-operative sickle cell screening.

The aim of this study was to determine the ethnic mix of those patients being pre-operatively screened for sickle cell disease in a London teaching hospital and to determine the rate of carriage of sickle haemoglobin amongst those tested. We retrospectively studied 1879 patients undergoing surgery over a 2-month period. Two hundred and thirteen (11%) were screened for sickle cell disease and of these, 12 (5%) tested positive for sickle cell trait (HbAS). There were no patients homozygous for sickle cell disease (HbSS) or with haemoglobin SC disease (HbSC). Screening rates varied widely in different ethnic groups from 0% of the Chinese population to 85.2% of the Afro-Caribbean population. We conclude that at present there is no coherent pre-operative screening policy for sickle cell disease in our institution. Sickle cell disease poses unique anaesthetic risks and with a rapidly expanding 'mixed race' population high-risk patients are difficult to identify phenotypically. We propose a universal screening policy be implemented in high-risk areas.

Cellular zinc content is a major determinant of iron chelator-induced apoptosis of thymocytes.

Desferrioxamine (DFO) and the hydroxypiridinone (HPO) deferiprone (CP20) chelate iron as well as other metals. These chelators are used clinically to treat iron overload, but they induce apoptosis in thymocytes. Thymocyte apoptosis is potentiated by zinc deficiency, suggesting that these iron chelators may induce apoptosis by depleting stores of zinc. Exposure of murine thymocytes to either DFO or deferiprone resulted in significant reductions in the labile intracellular zinc pool. Moreover, increasing intracellular zinc levels, by chronic zinc dietary supplementation to mice or in vitro loading with zinc, abrogated deferiprone-induced murine thymocyte apoptosis. Bidentate hydroxypyridinones such as deferiprone interact with intracellular zinc pools in a manner distinct from that of DFO, which is a hexadentate iron chelator. Whereas deferiprone acts synergistically with the zinc chelator NNNN-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) to induce apoptosis, DFO does not. This difference is most likely due to the ability of HPOs but not DFO to "shuttle" zinc onto acceptors such as metallothioneins. By nature of its structure, DFO is larger than deferiprone and is thus less able to access some intracellular zinc pools. Additionally, metal complexes of DFO are more stable than those of HPOs and thus are less likely to donate zinc to other acceptors. The ability of deferiprone to preferentially access zinc pools was also demonstrated by inhibition of a zinc-containing enzyme phospholipase C, particularly when combined with TPEN. These findings suggest that bidentate iron chelators access intracellular zinc pools not available to DFO and that zinc chelation is a mechanism of apoptotic induction by such chelators in thymocytes.

Coronary artery bypass graft surgery in a patient with haemoglobin SC disease.

Patients with sickle cell disease who undergo surgery are generally considered to be at greater risk of peri-operative complications than otherwise healthy patients. We report a case of a woman with haemoglobin SC disease undergoing coronary artery bypass grafting. She was successfully managed with pre-operative exchange transfusion and normothermic cardiopulmonary bypass.

The use of skin Fe levels as a surrogate marker for organ Fe levels, to monitor treatment in cases of iron overload.

A system based on the detection of K-shell x-ray fluorescence (XRF) has been used to investigate whether a correlation exists between the concentration of iron in the skin and the concentration of iron in the liver, as the degree of iron loading increases. The motivation behind this work is to develop a non-invasive method of determining the extent of the body's iron stores via measurements on the skin, in order to monitor the efficacy of chelation therapy administered to patients with beta-thalassaemia. Sprague-Dawley rats were iron loaded via injections of iron dextran and subsequently treated with the iron chelator CP94. The non-haem iron concentrations of the liver, heart and spleen were determined using bathophenanthroline sulphonate as the chromogen reagent. Samples of abdominal skin were taken and the iron concentrations determined using XRF. A strong correlation between the skin iron concentration and the liver iron concentration has been demonstrated (R2 = 0.86). Similar correlations exist for the heart and the spleen. These results show that this method holds great potential as a tool in the diagnosis and treatment of hereditary haemochromatosis and beta-thalassaemia.

One antigen mismatched related donor bone marrow transplant in a patient with acute lymphoblastic leukaemia and beta-thalassaemia major: potential cure of both marrow disorders.

We report a case of a 34-year-old man with T-ALL and beta-thalassaemia major who underwent a one antigen mismatched related donor bone marrow transplant. Five months post transplant chimeric studies revealed full donor haemopoiesis and the patient remains leukaemia and thalassaemia free at 12 months post transplant. Cumulative risk factors contributing to the increased transplant-related mortality in patients with two different marrow disorders are discussed.

Effect of oral micronized purified flavonoid fraction treatment on leukocyte adhesion molecule expression in patients with chronic venous disease: a pilot study.

PURPOSE: The purpose of this study was to determine the effects of a micronized purified flavonoid fraction treatment on surface expression of leukocyte adhesion molecules in chronic venous disease (CVD). METHODS: Twenty patients with chronic venous disease were assessed with the use of clinical and Duplex scanning criteria. Consenting patients were treated for 60 days with a micronized purified flavonoid fraction treatment (500 mg twice daily). Blood was collected from a foot vein immediately before the start of treatment and within 1 week after the treatment was stopped. Neutrophil and monocyte surface adhesion molecule expression was determined by flow cytometry using the monoclonal antibodies to CD11b and CD62L. RESULTS: Neutrophil CD11b (248:212), monocyte CD11B (204:190), neutrophil CD62L (130:97 [P =.002]), and monocyte CD62L (170:121 [P =.03]) were determined, respectively, before and after treatment. All values are arbitrary units and represent median values. CONCLUSION: Micronized purified flavonoid fraction treatment for 60 days seems to decrease the surface expression of CD62L by neutrophils and by monocytes. The clinical significance of this finding needs to be explored further. It is feasible to use changes in the levels of these molecules as a marker for response to therapy in chronic venous disease.

Determinants of iron status and bilirubin levels in congenital dyserythropoietic anaemia type I.

Seven untransfused patients with congenital dyserythropoietic anaemia type I were investigated to assess the determinants of both iron overload and serum bilirubin levels. The serum ferritin concentration was increased in all patients and non-transferrin-bound iron (NTBI) was increased in all but one patient. None of the patients showed the C282Y mutation in the hereditary haemochromatosis gene, HFE. One patient was homozygous for the H63D mutation in this gene. The data indicated that differences in the extent of iron overload were not mediated by co-inheritance of the C282Y mutation in the HFE gene but could largely be explained by differences in the severity of anaemia and ineffective erythropoiesis, and in the age of the patient. In one patient an unusually high plasma bilirubin level was associated with the variant A[TA]7TAA configuration in the TATA box of the uridine diphosphate glucuronosyltransferase (UGT-1A) gene promoter, the mutation found in most patients with mild Gilbert's syndrome.

Enhancement of 5-aminolaevulinic acid-induced photodynamic therapy in normal rat colon using hydroxypyridinone iron-chelating agents.

Currently, the clinical use of 5-aminolaevulinic acid (ALA)-induced protoporphyrin IX (PPIX) for photodynamic therapy (PDT) is limited by the maximum tolerated oral ALA dose (60 mg kg(-1)). This study investigates whether hydroxypyridinone iron-chelating agents can be used to enhance the tissue levels of PPIX, without increasing the administered dose of ALA. Quantitative charge-coupled device (CCD) fluorescence microscopy was employed to study PPIX fluorescence pharmacokinetics in the colon of normal Wistar rats. The iron chelator, CP94, when administered with ALA was found to produce double the PPIX fluorescence in the colonic mucosa, compared with the same dose of ALA given alone and to be more effective than the other iron chelator studied, CP20. Microspectrofluorimetric studies demonstrated that PPIX was the predominant porphyrin species present. PDT studies conducted on the colonic mucosa showed that the simultaneous administration of 100 mg kg(-1) CP94 i.v. and 50 mg kg(-1) ALA i.v. produced an area of necrosis three times larger than similar parameters without the iron-chelating agent with the same light dose. It is possible, therefore, to increase the amount of necrosis produced by ALA-induced PDT substantially, without increasing the administered dose of ALA, through the simultaneous administration of the iron-chelating agent, CP94.