Tomoyasu Suzuki

Inappropriate expression of hepcidin by liver congestion contributes to anemia and relative iron deficiency.

BACKGROUND Anemia and relative iron deficiency (RID) are prevalent in patients with heart failure (HF). The etiology of anemia and RID in HF patients is unclear. Hepcidin expression may be closely related to anemia and RID in HF patients. Although hepcidin is produced mainly by the liver, and the most frequent histologic appearance of liver in HF patients is congestion, the influence of liver congestion (LC) on hepcidin production has not yet been investigated. We investigated whether hepcidin contributed to anemia and RID in rats with LC. METHODS AND RESULTS LC was induced in rats by ligating the inferior vena cava and compared with bleeding anemia (BA) model induced by phlebotomy and hemolytic anemia (HA) model induced by injection of phenylhydrazine. BA and HA strongly suppressed expression of hepcidin in liver and so did not cause decrease in serum iron and transferrin saturation. However, hepcidin expression did not decrease in LC rats, which resulted in anemia and lower transferrin saturation. In addition, many cells with hemosiderin deposits were observed in the liver and spleen and not in the bone marrow, and this appeared to be related to suppression of hepcidin expression. Iron accumulated in hepatocytes, and bone morphogenetic protein 6, which induces hepcidin, increased. Inflammation was observed in the congestive liver, and there was an increase in interleukin-6, which also induced hepcidin and was induced by free heme and hemoglobin via Toll-like receptor 4. CONCLUSIONS We conclude that LC contributes to RID and anemia, and it does so via inappropriate expression of hepcidin.

Erythropoietin, but not asialoerythropoietin or carbamyl-erythropoietin, attenuates monocrotaline-induced pulmonary hypertension in rats.

Erythropoietin (EPO) has long been utilized for the treatment of renal anemia. The erythropoietin receptor (EPOR) is also expressed in the cardiovascular and central nervous systems in addition to an erythroid lineage, to provide an organoprotective role against several types of cellular stress. Pulmonary hypertension (PH) is a poor prognostic disease caused by primary and secondary pulmonary vascular injury. We observed the effects of EPO derivatives on monocrotaline-induced PH in rats on the supposition that EPO may protect small arteries from injury. Asialoerythropoietin (AEPO) lacks sialic acids in the termini of carbohydrate chains that results in rapid clearance from blood. Carbamyl-erythropoietin (CEPO) interacts with EPOR/βc heterodimers, but not with EPOR homodimers expressed in erythroid cells. Monocrotaline-injected rats were treated with continuous intravenous injection of 2500 ng/kg/day of EPO, AEPO, or CEPO for 21 days, and lung histology, cardiac function, and mRNA expression in the lungs were examined. Wall thickening of small arteries in the lungs and PH were improved by administration of EPO, but not by its non-hematopoietic derivatives, AEPO, or CEPO. Erythropoietin administration increased mRNA expression of the anti-apoptotic molecule, Bcl-xL, and maintained expression of the CD31 antigen. We conclude that lungs may express EPOR homoreceptors, but not heteroreceptors. Adequate serum erythropoietin levels may be essential for pulmonary protective effects.

Establishment of culturing system for ex-vivo expansion of angiogenic immature erythroid cells, and its application for treatment of patients with chronic severe lower limb ischemia

Angiogenesis therapy by bone marrow-mononuclear cell implantation (BMI) has been utilized. We found that erythroid cells played an essential role in angiogenesis by BMI. We then tried to establish a novel cell therapy by implantation of ex vivo expanded immature erythroblasts cultured from hematopoietic stem/precursor cells. Immature to mature erythroblasts were purified from human bone marrow, and mRNA expression were analyzed. Strongly expressed VEGF and PLGF in immature erythroid cells decreased according to erythroid maturation. To expand very immature erythroid cells, we established a two-step culturing system, i.e., bone marrow cells were cultured in the presence of Flt-3L, SCF and TPO for 7 days, and the cells were further cultured in the presence of SCF, IGF-I and EPO for an additional 7 days. The in vivo angiogenic effects of implantation of the ex vivo expanded cells were stronger than that of BMI in mouse limb ischemia model. Three patients with severe chronic lower limb ischemia accompanied by Burgers disease or collagen arteritis were enrolled in a pilot clinical trial of the novel cell therapy by transplantation of ex-vivo expanded immature erythroid cells. In the clinical trial, most clinical symptoms such as rest pain and skin ulcers improved in 4 weeks, and did not recur in the one-year follow-up. No adverse events were observed in any of the patients. Moreover this novel cell therapy required only a small amount of bone marrow collection. Further enrollment of patients with chronic severe lower limb ischemia is necessary to confirm the efficacy and safety of this novel cell therapy, and to estimate the necessary amount of bone marrow aspirate.

Improvement of anemia with decreasing hepcidin levels following valve replacement for severe tricuspid regurgitation

To the Editor: Severe right heart failure is occasionally accompanied by anemia (1, 2), but the underlying mechanisms for this association remain unknown. Hepcidin, a circulating hormone that is synthesized mainly by the liver, has emerged as a key regulator of systemic iron homeostasis (3). Hepcidin suppresses the expression of the iron transporter, ferroportin-1, thereby inhibiting the absorption of iron from the duodenum and the release of iron from the reticuloendothelial system. Therefore, the excessive production of hepcidin decreases serum iron levels, consequently causing and consequently causes anemia (3). Here, we report on a sixty-two-year-old woman of severe tricuspid regurgitation with refractory anemia in a patient with a very high serum hepcidin level who recovered from anemia after valve replacement, which was accompanied by a decrease in the hepcidin level. She had undergone mitral valve replacement for mitral stenosis 24 yrs before this episode. An echocardiogram revealed severe tricuspid regurgitation and dilatation of the right atrium. Right heart catheterization was performed after admission. Her right atrial pressure (RAP) was high (mean RAP, 15 mmHg; prominent V wave, 21 mmHg). Abdominal CT revealed hepatic vein dilatation and massive ascites. She received drug therapy for right heart failure, but this failed to reduce the massive ascites. She also had normocytic, normochromic anemia, but fecal occult blood tests were negative, and no bleeding source was found. She received oral iron preparation and red blood cell transfusions; however, her anemia did not resolve. As the massive ascites and progressive abdominal distension were believed to be life threatening, we decided to perform valve replacement surgery. The patient’s preoperative hemoglobin (Hb) level was 7.9 g ⁄dL, red blood cell (RBC) count was 271 million ⁄L, hematocrit (Ht) was 25.0%, serum iron level was low (26 lg ⁄dL), and serum ferritin level was high (724 ng ⁄mL; Table 1). Moreover, using a hepcidin EIA kit (Bachem Americans Inc., San Carlos, CA, USA), we found that her serum hepcidin levels (828 ng ⁄mL) were very high compared with the normal range (normal range, 1.8– 48.7 ng ⁄mL). Her preoperative serum C-reactive protein (CRP) level (15.91 mg ⁄dL) and interleukin-6 (IL-6) level (695 pg ⁄mL) were very high, but infectious disease was not found in any region of her body. Tricuspid valve replacement for severe tricuspid valve regurgitation and mitral valve replacement for the old ball valve were performed on July 1, 2010. Three months after the operation, the massive ascites completely disappeared. Postoperative right heart catheterization showed a decrease in RAP (mean RAP, 7 mmHg; V wave, 9 mmHg). Serum

Serum ferritin levels adversely affect cardiac function in patients with ST-elevation myocardial infarction who underwent successful percutaneous coronary intervention

Serum ferritin levels adversely affect cardiac function in patients with ST-elevation myocardial infarction who underwent successful percutaneous coronary intervention Tomoyasu Suzuki , Ken Toba ⁎, Kiminori Kato , Takuya Ozawa , Masutaka Higasimura , Toshiki Kitajima , Hirotaka Oda , Keiichi Tsuchida , Naohisa Tomosugi , Hideki Saitoh , Yoshifusa Aizawa a a First Department of Internal Medicine, Niigata University Medical and Dental Hospital, Niigata, Japan b Niigata City General Hospital, Niigata, Japan c Proteomics Research Unit, Kanazawa Medical University, Kanazawa, Japan d Chugai Pharmaceutical Co., Ltd, Tokyo, Japan

Involvement of cross-linked ribosomal protein S19 oligomers and C5a receptor in definitive erythropoiesis

We performed a series of experiments under a working hypothesis that cross-linked oligomers of ribosomal protein S19 (RP S19) play an essential role in definitive erythropoiesis as a ligand of the C5a receptor of erythroblasts and macrophages. We found molecules functionally and immunologically indistinguishable from RP S19 oligomers in the extracellular fluid of porcine and guinea pig bone marrow. When an increased hematopoietic state was induced in guinea pigs by bloodletting, the bone marrow RP S19 oligomer concentration was concomitantly increased. However, when the RP S19 oligomers were immunologically neutralized or the C5a receptor was pharmacologically antagonized, hyper-erythropoiesis induced by bloodletting was prevented and the anemic state was retarded in guinea pigs. When the RP S19 oligomers were neutralized in mice after bloodletting, the reactive hyper proliferation of erythroblasts in the spleen was prevented. Proerythroblasts and erythroblasts prepared by bone marrow aspiration from healthy individuals were found to express significant levels of the C5a receptor and type 2 transglutaminase genes. Majority of erythroblasts in cord blood of healthy newborns bore the C5a receptor. Taken together, these results support our hypothesis.

Liver Congestion in Heart Failure Contributes to Inappropriately Increased Serum Hepcidin despite Anemia

Hepcidin is a key regulator of mammalian iron metabolism and mainly produced by the liver. Hepcidin excess causes iron deficiency and anemia by inhibiting iron absorption from the intestine and iron release from macrophage stores. Anemia is frequently complicated with heart failure. In heart failure patients, the most frequent histologic appearance of liver is congestion. However, it remains unclear whether liver congestion associated with heart failure influences hepcidin production, thereby contributing to anemia and functional iron deficiency. In this study, we investigated this relationship in clinical and basic studies. In clinical studies of consecutive heart failure patients (n = 320), anemia was a common comorbidity (41%). In heart failure patients without active infection and ongoing cancer (n = 30), log-serum hepcidin concentration of patients with liver congestion was higher than those without liver congestion (p = 0.0316). Moreover, in heart failure patients with liver congestion (n = 19), the anemia was associated with the higher serum hepcidin concentrations, which is a type of anemia characterized by induction of hepcidin. Subsequently, we produced a rat model of heart failure with liver congestion by injecting monocrotaline that causes pulmonary hypertension. The monocrotaline-treated rats displayed liver congestion with increase of hepcidin expression at 4 weeks after monocrotaline injection, followed by anemia and functional iron deficiency observed at 5 weeks. We conclude that liver congestion induces hepcidin production, which may result in anemia and functional iron deficiency in some patients with heart failure.

Effects of erythropoietin administration on iron status in patients with ST-elevation myocardial infarction who underwent successful percutaneous coronary intervention

myocardial infarctionwho underwent successful percutaneous coronary intervention Tomoyasu Suzuki , Ken Toba ⁎, Kiminori Kato , Takuya Ozawa , Hiroshi Suzuki , Naohisa Tomosugi , Hideki Saitoh , Yoshifusa Aizawa a a First Department of Internal Medicine, Niigata University Medical and Dental Hospital, Niigata, Japan b Division of Cardiology, Department of Internal Medicine, Showa University Fujigaoka Hospital, Yokohama, Japan c Proteomics Research Unit, Kanazawa Medical University, Kanazawa, Japan d Chugai Pharmaceutical Co., Ltd, Tokyo, Japan

Combination therapy involving stenting and coil embolization for atherosclerotic narrowing complicated by a coronary aneurysm

There is controversy as to how atherosclerotic coronary artery aneurysms should be treated and managed because their prognosis is still unknown. This report describes a case in which atherosclerotic coronary narrowing accompanied by a saccular coronary aneurysm was successfully treated by combination therapy involving coil embolization to treat the aneurysm and stent implantation across the narrowing and the ostium of the aneurysm.

Erythropoietin induces angiogenesis in a manner dependent on the intrinsic auto/paracrine production of interleukin-6 in vitro

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