Tsugumi Takayama

Expression of the peptide hormone hepcidin increases in cardiomyocytes under myocarditis and myocardial infarction

The micronutrient iron is an essential component that plays a role in many crucial metabolic reactions. The peptide hormone hepcidin is thought to play a central role in iron homeostasis and its expression is induced by iron overloading and inflammation. Recently, hepcidin has been reported to be expressed also in the heart; however, the kinetics of altered hepcidin expression in diseases of the heart remain unknown. In this study, we examined cardiac expression of hepcidin in rat experimental autoimmune myocarditis (EAM), human myocarditis and rat acute myocardial infarction (AMI). In rat EAM and AMI hearts, hepcidin was expressed in cardiomyocytes; ferroportin, which is a cellular iron exporter bound by hepcidin, was also expressed in various cells. Analysis of the time course of the hepcidin to cytochrome oxidase subunit 6a (Cox6a)2 expression ratio showed that it abruptly increased more than 100-fold in hearts in the very early phase of EAM and in infarcted areas 1 day after MI. The hepcidin/Cox6a2 expression ratio correlated significantly with that of interleukin-6/gamma-actin in both EAM and AMI hearts (r=0.781, P<.0001 and r=0.563, P=.0003). In human hearts with histological myocarditis, the ratio was significantly higher than in those without myocarditis (0.0400+/-0.0195 versus 0.0032+/-0.0017, P=.0045). Hepcidin is strongly induced in cardiomyocytes under myocarditis and MI, conditions in which inflammatory cytokine levels increase and may play an important role in iron homeostasis and free radical generation.

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.

Prognosis of Cancer Patients with Aortic Stenosis Under Optimal Cancer Therapies and Conservative Cardiac Treatments: A Single Cancer Center Study with 92 Consecutive Patients

Aortic stenosis (AS) is a life-threatening comorbidity of cancer patients. Aortic valve replacement (AVR) should be considered for some cancer patients, but neither the characteristics nor prognosis under conservative therapy is well known.We searched our echocardiography log (years 2005-2014) for cancer patients with AS, and 92 patients (54% female) were included in the study. To compare the survival curves, 470 control patients without AS were selected from our cancer registry.Mean age (± SD) was 77.6 ± 6.7 years for males and 81.6 ± 6.3 years for females. Mean aortic valve area (AVA) was 1.0 ± 0.3 cm2. Stomach, blood, and urinary bladder cancers were the major sites of current cancer. During the 5-year follow-up period, 44 patients with AS (48%) died; 26 (59%) due to cancer progression, 10 (23%) heart failure, and 4 (9%) stroke. Heart-failure death was significantly higher for patients with AS than for control patients (P < 0.001). Kaplan-Meier survival estimates were worse for stage I or II patients with AVA < 0.75 cm2 than for control patients (P = 0.016). Older age, advanced stages, absence of dyslipidemia, recent syncope, and chronic heart failure or AVA < 0.75 cm2 were significantly and independently associated with poor survival.Although the majority of cancer patients with AS died of cancer, a quarter died of heart failure. Careful follow-up is needed because cancer patients at earlier stages with symptomatic AS or AVA < 0.75 cm2 should be considered for AVR.

A novel synthetic derivative of human erythropoietin designed to bind to glycosaminoglycans

To synthesize long-acting and antiangiogenic erythropoietin to be clinically applied for treatment of patients with solid tumors, we synthesized a hybrid molecule of human erythropoietin added onto the C-terminus with a heparin-binding motif of human PLGF-2 to develop a novel derivative of long-acting and antiangiogenic erythropoietin: heparin-binding erythropoietin (HEPO), and studied the characteristics of this novel erythropoietin derivative. HEPO cDNA was synthesized, expressed in insect cells, and the protein was purified using a heparin-sepharose affinity column. The erythropoietic and angiogenic effects of the partially purified protein were analyzed in vitro and in vivo. The erythropoietic activity of the protein was equivalent to natural EPO in vitro. In vivo administration of the protein to mice revealed its long-acting erythropoietic activity as expected. Administration of the protein inhibited angiogenesis in a mouse limb ischemia model. In conclusion, the heparin-binding motif of PLGF-2 may act as, so to speak, a superendostatin. This novel long-acting erythropoietin derivative may have an advantage to inhibit tumor growth while preserving hematopoietic and tissue-protective effects.

A Case of Aortic Regurgitation Presenting with Recurrent Detachment of a Prosthetic Valve, as the First Presenting Symptom of Cardiovascular Behçet's Disease

A 33-year-old man with severe aortic regurgitation underwent initial aortic valve replacement (AVR). During the 2 years after AVR, 3 reoperations for prosthetic valve detachment were required. During hospitalization, he had no typical clinical findings, with the exception of a persistent inflammatory reaction; a pseudo-aneurysm around the Bentall graft developed 27 days after the 4th operation. This unique clinical course suggested the possibility of Behçets disease. In the 8 years of follow-up after the administration of prednisolone, the pseudo-aneurysm did not become enlarged and the detachment of the prosthetic valve was not observed. We herein present a case of cardiovascular Behçets disease, with a review of the literature.

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

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