Cardiovascular and Respiratory Toxicity of Protamine Sulfate in Zebrafish and Rodent Models

A case of the effective inhalation of nitric oxide therapy for caused severe pulmonary hypertension with protamine neutralization of systemic heparinization during totally endoscopic minimally invasive cardiac surgery

Severe pulmonary vasoconstriction induced by protamine is a rare complication. We report a case of a 77-year-old male patient with a history of mitral valve plasty (MVP). He underwent redo MVP via right thoracotomy under the totally endoscopic procedure (MICS redo-MVP). Immediately after weaning cardiopulmonary bypass (CPB), protamine was administrated. 10 min later peak systolic pulmonary arterial pressure (sys PAP) rose to 62 mmHg, and 30 min later to 80 mmHg. Due to the negative impact of protamine administration, nitric oxide inhalation (iNO) therapy was started with a concentration of 20 ppm. 10 min after iNO therapy started, sys PAP decreased to 63 mmHg. After entering the intensive care unit (ICU), sys PAP decreased to 35 mmHg. Here, we present an effective iNO therapy case for pulmonary hypertension due to protamine and the patient had a good postoperative recovery. This study was approved by the Institutional Review Board at Kitaharima Medical Center (IRB-0602) with the waiver of informed consent.

Discovery of a highly selective fluorescent probe for hydrogen peroxide and its biocompatibility evaluation and bioimaging applications in cells and zebrafish

As one of the most widely distributed reactive oxygen species in vivo, hydrogen peroxide plays divergent and important roles in cell growth, differentiation and aging. When the level of hydrogen peroxide in the body is abnormal, it will lead to genome mutation and induce irreversible oxidative modification of proteins, lipids and polysaccharides, resulting in cell death or even disease. Therefore, it is significant to develop a sensitive and specific probe for real-time detection of hydrogen peroxide in vivo. In this study, the response mechanism between hydrogen peroxide and probe QH was investigated by means of HRMS and the probe showed good optical properties and high selectivity to hydrogen peroxide. Note that the evaluating of probe biocompatibility resulted from cytotoxicity test, behavioral test, hepatotoxicity test, cardiotoxicity test, blood vessel toxicity test, immunotoxicity test and neurotoxicity test using cell and transgenic zebrafish models with more than 20 toxic indices. Furthermore, the detection performance of the probe for hydrogen peroxide was evaluated by multiple biological models and the probe was proved to be much essential for the monitoring of hydrogen peroxide in vivo.

Hypoglycemic and hypolipidemic effect of pentaamino acid fullerene C60 derivative in rats with metabolic disorder

Pentaamino acid fullerene C₆₀ derivative is a promising nanomaterial, which exhibited antihyperglycemic activity in high-fat diet and streptozotocin-induced diabetic rats. This study investigates the effect of pentaaminoacid C₆₀ derivative (PFD) in rats with metabolic disorders. Rats were assigned to 3 groups (of 10 rats each) as follows: Group 1 (normal control), group 2 included the protamine-sulfate-treated rats (the untreated group of animals with the model metabolic disorder); group 3 (Protamine sulfate + PFD) included the protamine-sulfate-treated model rats that received an intraperitoneal injection of PFD. Metabolic disorder in rats was initiated by protamine sulfate (PS) administration. The PS + PFD group was injected intraperitoneally with PFD solution (3 mg/kg). Protamine sulfate induces biochemical changes (hyperglycemia, hypercholesterolemia, and hypertriglyceridemia) in the blood and morphological lesions in rat liver and pancreas. The potassium salt of fullerenylpenta-N-dihydroxytyrosine in protamine sulfate-induced rats normalized blood glucose level and the serum lipid profile and improved hepatic function markers. Treatment with PFD restored pancreas islets and liver structure of protamine sulfate-induced rats compared to the untreated group. PFD is a promising compound for further study as a drug against metabolic disorders.

Monitoring of Anticoagulant Activity of Dabigatran and Rivaroxaban in the Presence of Heparins

The routine monitoring of direct oral anticoagulants (DOACs) may be considered in patients with renal impairment, patients who are heavily obese, or patients requiring elective surgery. Using the heparin-binding copolymer (HBC) and polybrene, we aimed to develop a solution for monitoring the anticoagulant activity of DOACs in human plasma in the interfering presence of unfractionated heparin (UFH) and enoxaparin. The thrombin time (TT) and anti-factor Xa activity were monitored in pooled plasma from healthy volunteers. In these tests, plasma with dabigatran or rivaroxaban was mixed with UFH or enoxaparin and then incubated with HBC or polybrene, respectively. HBC and polybrene neutralized heparins and enabled monitoring of anticoagulant activity of dabigatran in the TT test. Both agents allowed for accurate measurement of anti-factor Xa activity in the plasma containing rivaroxaban and heparins in the concentration range reached in patients’ blood. Here, we present diagnostic tools that may improve the control of anticoagulation by eliminating the contamination of blood samples with heparins and enabling the monitoring of DOACs’ activity.

Reversal Activity and Toxicity of Heparin-Binding Copolymer after Subcutaneous Administration of Enoxaparin in Mice

Uncontrolled bleeding after enoxaparin (ENX) is rare but may be life-threatening. The only registered antidote for ENX, protamine sulfate (PS), has 60% efficacy and can cause severe adverse side effects. We developed a diblock copolymer, heparin-binding copolymer (HBC), that reverses intravenously administered heparins. Here, we focused on the HBC inhibitory activity against subcutaneously administered ENX in healthy mice. BALB/c mice were subcutaneously injected with ENX at the dose of 5 mg/kg. After 110 min, vehicle, HBC (6.25 and 12.5 mg/kg), or PS (5 and 10 mg/kg) were administered into the tail vein. The blood was collected after 3, 10, 60, 120, 360, and 600 min after vehicle, HBC, or PS administration. The activities of antifactors Xa and IIa and biochemical parameters were measured. The main organs were collected for histological analysis. HBC at the lower dose reversed the effect of ENX on antifactor Xa activity for 10 min after antidote administration, whereas at the higher dose, HBC reversed the effect on antifactor Xa activity throughout the course of the experiment. Both doses of HBC completely reversed the effect of ENX on antifactor IIa activity. PS did not reverse antifactor Xa activity and partially reversed antifactor IIa activity. HBC modulated biochemical parameters. Histopathological analysis showed changes in the liver, lungs, and spleen of mice treated with HBC and in the lungs and heart of mice treated with PS. HBC administered in an appropriate dose might be an efficient substitute for PS to reverse significantly increased anticoagulant activity that may be connected with major bleeding in patients receiving ENX subcutaneously.