The role of anemia in congestive heart failure and chronic kidney insufficiency: the cardio renal anemia syndrome

Anemia is a major problem in patients with chronic kidney insufficiency. The development of recombinant human erythropoietin has enabled physicians to correct this anemia. Although anemia has not been considered to be a common or important contributor to congestive heart failure, anemia of any cause can lead to cardiac damage and eventually congestive heart failure. Our joint renal-cardiac heart failure team found that anemia was indeed very common in congestive heart failure and was associated with severe, medication-resistant cardiac failure. Correction of the anemia with erythropoietin and intravenous iron led to a marked improvement in patients' functional status and their cardiac function, and to a marked fall in the need for hospitalization and for high-dose diuretics; renal function usually improved or at least stabilized. Subsequent investigations by others have confirmed many of our observations. We call this interrelationship between congestive heart failure, chronic kidney insufficiency, and anemia the Cardio-Renal Anemia syndrome. Treatment of the anemia in congestive heart failure may prove vital in preventing progression of both the heart failure and the associated renal disease.     

Calcium-dependent association of glutathione S-transferase with the human erythrocyte membrane

Elevations in intracellular calcium increase the adsorption of a cytoplasmic protein to human red blood cell membrane. This protein migrates on SDS polyacrylamide gels at 23,000 daltons and has been called band 8. The association of this protein with the membrane is increased in sickle cell anemia. This protein is extracted from the membrane with EGTA, a calcium chelator. Enzymatic and immunological studies identify band 8 as a glutathione S-transferase.     

Role of iron metabolism in heart failure: From iron deficiency to iron overload

Iron metabolism is a balancing act, and biological systems have evolved exquisite regulatory mechanisms to maintain iron homeostasis. Iron metabolism disorders are widespread health problems on a global scale and range from iron deficiency to iron-overload. Both types of iron disorders are linked to heart failure. Iron play a fundamental role in mitochondrial function and various enzyme functions and iron deficiency has a particular negative impact on mitochondria function. Given the high-energy demand of the heart, iron deficiency has a particularly negative impact on heart function and exacerbates heart failure. Iron-overload can result from excessive gut absorption of iron or frequent use of blood transfusions and is typically seen in patients with congenital anemias, sickle cell anemia and beta-thalassemia major, or in patients with primary hemochromatosis. This review provides an overview of normal iron metabolism, mechanisms underlying development of iron disorders in relation to heart failure, including iron-overload cardiomyopathy, and clinical perspective on the treatment options for iron metabolism disorders.     

Biochemical and immunological markers of insufficiency of blood circulation in children with cardiomyopathies

Complex clinical-laboratory investigation of children with congestive heart failure developed on the basis of dilated cardiomyopathy and hypertrophic cardiomyopathy has been carried out. The development of congestive heart failure in children with cardiomyopathy was accompanied by changes in activity of creatine phosphokinase, MB isoform of creatine phosphokinase, and also blood serum lactate, neopterin, TNF-α, interleukin-2 (IL-2), interleukin-6 (IL-6), and the soluble receptors for IL-2 and IL-6 (sIL-2R, sIL-6R). The energy deficit in patients with congestive heart failure is associated with pronounced impairments of expression of neopterin, TNF-α, IL-2, IL-6 and their receptors. The role of cytokines in formation of dysregulation processes is analyzed at the level of intercellular and organ local interactions. A cascade of multiple biochemical and molecular processes including impairments of membrane integrity and ion transport, apoptosis, proteolysis followed by fibrosis of myocardium finally cause myocardial remodeling, the development, chronization and progression of congestive heart failure in children with cardiomyopathy.     

Variations in the relative activities of erythrocyte membrane ATPase with changes in severity of sickle cell anemia

Red blood cells from 31 patients with sickle cell anemia whose hemoglobins were ascertained as SS were assayed for Mg-, Ca-, Na-, and total ATPase activities. The ATPase activities were correlated with the various stages of severity in each patient as determined by clinical parameters. The results demonstrate that increases in ATPase activities were associated with increases in the percentage severity of sickle cell anemia. Severity correlated inversely with fetal hemoglobin levels in the sickle cell patients. ATPase activities were generally higher in SS genotypes than in AS and AA normal individuals.     

The effect of hemin in vitro and in vivo on human erythroid progenitor cells

Hemin stimulates erythropoiesis and hemoglobin synthesis in vitro. We cultured erythroid progenitor cells from normal individuals, patients with sickle cell anemia, and a patient with acute variegate porphyria who received intravenous hemin treatment, with 0-800 microM hemin added in vitro. Fifty to 200 microM hemin consistently stimulated colony growth from normal donors 2- to 8-fold, while concentrations of up to 400 microM were stimulatory in cultures from donors with sickle cell anemia. In vivo hemin decreased the number of blood BFU-e in the patient with porphyria, but did not abrogate the in vitro stimulatory effect of hemin. Hemin concentrations which increased colony numbers increased gamma globin synthesis in some studies and decreased it in others. Hemin thus has clearcut erythroid growth-potentiating activity, although a consistent effect on globin chain regulation is not apparent.     

Measurement of fluxes through the pentose phosphate pathway in erythrocytes from individuals with sickle cell anemia by carbon-13 nuclear magnetic resonance spectroscopy

Erythrocytes from individuals with sickle cell anemia have previously been shown to have increased levels of intracellular oxidants and increased oxidative damage. Oxidative damage has been implicated in the events leading to the painful crises and hemolytic anemia found in sickle cell anemia. Since the pentose phosphate pathway (PPP) is an important source of reducing capacity in erythrocytes, we have investigated the fluxes through the PPP in normal and sickle cell erythrocytes using [2-¹³C]D-glucose and carbon-13 nuclear magnetic resonance (NMR) spectroscopy. Our results indicate that sickle cell erythrocytes have a flux through the PPP of 0.13±0.02 μmol/h per ml erythrocytes that is comparable to that in normal erythrocytes, 0.21±0.02 μmol/h per ml erythrocytes. However, when stimulated with methylene blue, sickle cell erythrocytes show a decreased response, 0.59±0.10 μmol/h per ml erythrocytes, compared to normal erythrocytes, 1.64±0.10 μmol/h per ml erythrocytes. When homogeneous populations of sickle cell erythrocytes are isolated by density gradient centrifugation, the rate of flux through the PPP in methylene blue-stimulated sickle cell erythrocytes, 1.16±0.16 μmol/h per ml erythrocytes, approaches that in methylene blue-stimulated normal erythrocytes. In addition, by analyzing the dose response to methylene blue, we have found that the decreased stimulation of the PPP by methylene blue in heterogeneous populations of sickle cell erythrocytes is a failure of methylene blue to simulate the PPP rather than a deficiency in the PPP in sickle cell erythrocytes.     

Prevalence of diabetes mellitus in individuals heterozygous and homozygous for sickle cell anemia

Colorimetric determinations of glycosylated Hb were carried out in a sample (n = 97) of sickle cell anemia patients, and in an age- and sex-matched group of individuals (n = 45) heterozygous for sickle cell anemia, from the Eastern Province of Saudi Arabia. A statistically significant increase in the value of glycosylated Hb was found in sickle cell trait (HbAS) group, when compared with those of sickle cell anemia (HbSS) and normal (HbAA) groups. Since glycosylated Hb is considered a valid indicator of long-term blood glucose, and assuming normal red blood cell survival in HbAS carriers, the increased value of glycosylated Hb may suggest that there exists a higher incidence of undiagnosed diabetes mellitus in individuals with heterozygous inheritance for sickle cell hemoglobin than homozygous sickle cell patients and normal individuals. The mechanism underlying this observation remains to be defined.     

Elution of interferon beta from blue sepharose by poly(vinylpyrrolidone)

Pre-equilibration of erythrocytes with the membrane-impermeable aldehyde, pyridoxal 5'-phosphate, for 30 min at 22 degrees C, prior to the addition of methyl acetimidate to the incubation mixture has been shown to prevent agglutination of acetamidinated cells which were resuspended in immune serum (Chao, T.L. and Berenfeld, M.R. (1981) J. Biol. Chem. 256, 5324-5326). This observation led to the possibility that the immune reaction, observed in some sickle cell anemia patients to reinfused cells which had been reacted with methyl acetimidate, could be prevented. The present communication further evaluates that reaction sequence and shows that while the pre-equilibration of cells with pyridoxal 5'-phosphate does protect membrane amines from reaction with methyl acetimidate, the protection is not extensive enough to prevent an immune response in a sickle cell anemia patient who had already been sensitized against acetamidinated cells. It is apparent that the design of antisickling agents which covalently modify hemoglobin must take into account protection of functional groups in the erythrocyte membrane, modification of which could produce an immunogenic response.     

Hematological and hemorheological Determinants of the Six-Minute Walk Test Performance in Children with Sickle Cell Anemia

The six-minute walk test is a well-established submaximal exercise reflecting the functional status and the clinical severity of sickle cell patients. The aim of the present cross-sectional study was to investigate the biological determinants of the six-minute walk test performance in children with sickle cell anemia. Hematological and hemorheological parameters, pulmonary function and the six-minute walk test performance were determined in 42 children with sickle cell anemia at steady state. The performance during the six-minute walk test was normalized for age, sex and height and expressed as percentage of the predicted six-minute walk distance. We showed that a high level of anemia, a low fetal hemoglobin expression and low red blood cell deformability were independent predictors of a low six-minute walk test performance. This study describes for the first time the impact of blood rheology in the six-minute walk test performance in children with sickle cell anemia.     

Reduced water exchange in sickle cell anemia red cells: a membrane abnormality

We have measured the diffusional water permeability of sickle cell anemia red blood cells under isotonic conditions using pulsed nuclear magnetic resonance (NMR) techniques. We have found that the equilibrium diffusional permeability for sickle cells is about 1.61.10(-3) cm/s, or about 60% of the value measured for normal cells. This abnormality is not related to the heterogeneity generally found in cell populations in sickle red cells with different mean corpuscular hemoglobin concentrations. We speculate that the abnormality of water exchange under isotonic conditions in sickle cells reflects an alteration of membrane proteins responsible for water exchange, possibly caused by oxidation of Band 3 proteins.     

Effect of erythropoietin in a patient with severe congestive heart failure--a case report

Erythropoietin (EPO), traditionally known as a hematopoietic hormone, has recently been shown to have effects beyond hematopoiesis such as prevention of neuronal and cardiac apoptosis secondary to ischemia and induction of neoangiogenesis. Patients with congestive heart failure (CHF) suffer considerable morbidity and mortality despite advances in therapy. Anemia, CHF, and chronic kidney insuficiency often coexist and interact to cause or worsen each other in the so-called cardio-renal anemia syndrome. Treatment with EPO has shown promise in such patients. The paper reviews a case of a successful recovery of cardiac function in a patient with a severe CHF during the treatment with EPO.     

The use of a free flap in homozygous sickle cell disease

This paper describes what is thought to be the first reported use of a free flap in a patient with homozygous sickle cell disease. The utilization of a free flap in homozygous sickle cell disease should be questioned because the obligate period of ischemia to which the flap must be subjected during the transfer from donor to recipient sites might lead to intravascular sickling in the flap and flap failure. Review of the literature suggests that by reducing the level of sickle hemoglobin to the range of 25 to 40 percent, the risk of failure of a free flap is not significantly increased in the homozygous sickle cell patient. Furthermore, there is good evidence to suggest that a well-vascularized muscle flap provides optimal coverage, reversing the pathophysiologic cycle of the sickle cell ulcer. Thus in cases of multiply recurrent sickle cell ulcers in areas devoid of a local well-vascularized muscle flap, a free muscle flap is indicated, may be the procedure of choice, and can be performed successfully. We report a patient with a 4-year history of multiple recurrent sickle cell ulcers of the left ankle treated with a gracilis free flap. This patient has been followed for 2 years and continues to be free of recurrent ulceration.     

Detection of different developmental stages of malaria parasites by non-radioactive DNAin situ hybridization

Summary A highly sensitive non-radioactive DNAin situ hybridization procedure is described that enables detection and unequivocal identification of various developmental stages of human and rodent malaria parasites. Using biotinylated species-specific DNA probes, erythrocytic parasites can be specifically stained in blood smears. Similarly exoerythrocytic stages can be visualized in cell culture and in sections of paraffin-embedded liver. In blood smears, the hybridization procedure provides a rapid detection of (low) parasitemia and species-determination for experienced microscopists at 100 to 400x magnification. Moreover, the procedure can be applied even after previous Giemsa staining of the preparation, enabling revision of patient smears which were difficult to read after routine Giemsa staining.     

Differences in erythrocyte membrane proteins and glycoproteins in sickle cell disease

Erythrocyte membrane proteins obtained from individuals with sickle cell anemia show an SDS polyacrylamide gel pattern that differs in five regions from the normal pattern. These membranes when compared with membranes from normal individuals also show a marked decrease in sialic acid content which correlates with a marked reduction of the periodic acid-Schiff staining of the three major glycoprotein components. The observed membrane protein and glycoprotein changes are a characteristic of all the red cells in sickle cell anemia and do not correlate with the proportion of irreversibly sickled cells.     

What's new and what's true of what's new in dermatology

Within the past few years it has been noted that abnormal types of hemoglobin found in certain persons are associated with definite clinical disorders. At least four different varieties of sickle cell anemia are now recognized, three of them being heterozygous and one homozygous. When the gene for sickling is represented once, the person is asymptomatic and is said to have "sickle cell trait." However, when the sickle cell trait is present in combination with certain other hemoglobin abnormalities such as hemoglobin C or D or with thalassemia trait, symptomatic clinical disease results. The homozygous condition, in which two genes for hemoglobin C are present in the same person, has been observed in a few instances. A similar condition as regards hemoglobin D has not as yet been recognized.     

Experimental and Imaging Techniques for Examining Fibrin Clot Structures in Normal and Diseased States

Fibrin is an extracellular matrix protein that is responsible for maintaining the structural integrity of blood clots. Much research has been done on fibrin in the past years to include the investigation of synthesis, structure-function, and lysis of clots. However, there is still much unknown about the morphological and structural features of clots that ensue from patients with disease. In this research study, experimental techniques are presented that allow for the examination of morphological differences of abnormal clot structures due to diseased states such as diabetes and sickle cell anemia. Our study focuses on the preparation and evaluation of fibrin clots in order to assess morphological differences using various experimental assays and confocal microscopy. In addition, a method is also described that allows for continuous, real-time calculation of lysis rates in fibrin clots. The techniques described herein are important for researchers and clinicians seeking to elucidate comorbid thrombotic pathologies such as myocardial infarctions, ischemic heart disease, and strokes in patients with diabetes or sickle cell disease.     

Abnormal membrane protein methylation and merocyanine 540 fluorescence in sickle erythrocyte membranes

Sickle cell erythrocytes exhibit reduced carboxyl methylation of membrane proteins compared to normal erythrocytes. This altered methylation in sickle membrane proteins is also observable when extracted membranes, both intact and alkali treated, were used as substrates for the homologous protein methylase II (S-adenosylmethionine:protein-carboxyl O-methyltransferase, EC. 2.1.1.24). However, when glycophorin A, one of the major methyl acceptors in both membranes, was extracted by lithium diiodosalicylate and used as the methyl acceptor, the proteins from both membranes were methylated equally, suggesting an involvement of membrane structure in membrane-bound protein methylation. Merocyanine 540 (MC-540), a fluorescent probe, was used to determine if the membranes differed in organization. Incubation of both normal and sickle erythrocytes membranes with MC-540 produced a marked increase in extrinsic fluorescence, reflecting a relatively nonpolar environment for the dye bound to the membranes. The fluorescence from sickle cell ghosts was only 87% as intense as that from normal ghosts, while the actual amount of MC-540 associated with sickle cell membranes was only 62% of normal. These data suggest that differences exist in the distribution of surface charges on these plasma membranes. These results are consistent with the hypothesis that abnormal levels of membrane protein methylation observed in sickle erythrocytes may be a result of abnormal membrane organization characteristic to sickle cell anemia.     

Massive sequestration of human sickle cells after transfusion to a baboon

A baboon was exchange-transfused with sickle cell anemia patients' blood. The animal died suddenly, and postmortem examination showed widespread red cell sequestration, particularly in the spleen and liver. The clinical and pathological findings were similar to those in children with sickle cell anemia who die of acute splenic sequestration syndrome. A control animal, exchange-transfused with normal human blood, tolerated the procedure without difficulties for a period of 4 days, when a delayed transfusion reaction occurred. Thus the baboon can be used as a model for the abnormal circulatory behavior of sickle cells and for the sickle cell sequestration syndrome.     

肾脏去神经化在心力衰竭治疗中的研究进展

生理情况下,心脏和肾脏在血流动力学和神经激素等调节中相互作用,对于循环系统的稳态维持起重要作用。但在充血性心力衰竭的病理情况下,心脏和肾脏之间存在明显的调节紊乱。首先,急性失代偿性心力衰竭的患者住院治疗的研究结果证明其有一定程度的肾脏失调。其次,慢性充血性心力衰竭时肾脏交感神经系统也起到重要作用:肾脏交感纤维活性增强可导致肾素的释放、钠水潴留、肾血流的降低、血管阻力增加、左心室重塑、左心功能失调等。众所周知,肾脏交感神经切除术可以减低血压和改善心脏功能,但是由于有创的手术方式限制了其应用。过去两年间,随着新的导管消融肾脏去神经化技术的日益完善,其有望成为治疗高血压病和心力衰竭的手段。在此,本文综述了心力衰竭时肾脏交感传入神经和传出神经的发病机理,对目前进行的经导管肾脏去神经化治疗慢性心力衰竭的基础及临床试验进行安全性及有效性评价。提示我们经导管肾脏去神经化有望成为心力衰竭治疗的新靶点。