Prolonged functional life span of artificial red cells in blood circulation by repeated methylene blue injections

Abstract

Hemoglobin-vesicles (HbVs) are artificial oxygen carriers encapsulating purified and concentrated hemoglobin solution in phospholipid vesicles (liposomes) and their safety and efficacy as a transfusion alternative have been evaluated. Because of the absence of enzymatic methemoglobin reduction system in HbV, the level of ferric methemoglobin (metHb) increases gradually after intravenous administration. Our previous studies clarified that the glycolytic electron energies, charged as NAD(P)H in red blood cells (RBC), are donated to reduce metHb compartmentalized in HbV via a water-soluble electron mediator such as methylene blue [MB; 3,7-bis(dimethylamino)phenothiazinium chloride], which freely shuttle across both RBC biomembrane and HbV lipid membrane. Herein, we tried to test repeated injections of MB after the massive HbV administration (28 mL/kg) to hemorrhagic shocked Wistar rats (n ¼ 3). MB was injected (3.1 mg/kg) at 7, 24 and 48 h after HbV administration. Every MB injection showed rapid reduction of metHb and gradual reversal increase. As a result, the functional life span of HbV was significantly extended over 60 h. It is expected that further optimization of injection scheduling will decrease the total amount of MB and prolong the functional life span of HbV. ARTICLE HISTORY

Hemoglobin–albumin clusters as an artificial O2 carrier: Physicochemical properties and resuscitation from hemorrhagic shock in rats

“…The metHb ratio of HbBv–HSA 3 in the bloodstream was only 14% at 3 h after administration. It was much lower than the value of Hb‐vesicle 38 . We reported earlier that HbBv–HSA 3 showed a similar autoxidation rate constant ( k ox ) to that of native HbBv 39 .…”

“…It was much lower than the value of Hb-vesicle. 38 We reported earlier that HbBv-HSA 3 showed a similar autoxidation rate constant (k ox ) to that of native HbBv. 39 In general, HBOCs exhibit larger k ox values relative to naked Hb.…”

Assessment of synthetic red cell therapy for extremely preterm ovine fetuses maintained on an artificial placenta life‐support platform

“…Methemoglobinemia was determined as MetHb > 10%. When MetHb values increase above 10%, methylene blue Injection (MB; 2 mg/kg/h, Akorn, Inc, Lake Forest, Illinois, U.S) was administered as reported previously 29,30 …”

“…The circuit volume was modified respectively according to the length of tubes and primed with 45-80 ml of different types of HbV compounds (Tables 1 and 2). 1 and 2) HbVs were prepared as described previously, and the half-life of HbV in animals was estimated to be approximately 48 to 72 h. [28][29][30] Compounds A-C for priming solutions of APT were constituted using HbV and sheep albumin suspended in phosphate-buffered saline (25% concentration, Sigma-Aldrich, Burlington, United States), potassium chloride (1 mmol/ml, Otsuka Pharmaceutical CO, Ltd., Tokyo, Japan), sodium phosphate (0.5 mmol/ml, Otsuka Pharmaceutical CO, Ltd., Tokyo, Japan), calcium gluconate hydrate (0.39 mmol/L, Nichi-Iko Pharmaceutical, Tokyo, Japan), vitamin compounds suspended by 5 ml of 5% glucose solution (Daimedin multi injection; Nichi-Iko Pharmaceutical, Tokyo, Japan), micronutrients (Cizanarine N Injection; Nissin Pharmaceutical, Yamagata, Japan), sodium bicarbonate (1 mmol/ml, Otsuka Pharmaceutical CO, Ltd., Tokyo, Japan), trometamol (THAM inj set; 0.3 mmol/ml, Otsuka Pharmaceutical CO, Ltd., Tokyo, Japan) and lipo-prostaglandin E1 (PGE1) (Alprostadil; 5 µg/ml, Sawai Pharmaceutical CO, Ltd. Osaka, Japan) as shown in Table 2.…”

“…Although the half‐life of HbV is estimated as 48–72 h, approximately 40% of HbVs change into MetHb in first 6 h after transfusion. Given this, we used RBC transfusions to stabilize functional Hb values above 10 g/dl (Figure 1 f ) 28–30,40 …”