Inhibitory effect of a new synthetic protease inhibitor (FUT-175) on the coagulation system

Elucidation of the mechanism of precipitate formation on mixing nafamostat mesylate solution with dialysate

This study clarifies the reagent preparation and administration conditions that lead to precipitation when nafamostat mesylate salt (NM) solution is mixed with dialysate. The objective is to elucidate the mechanism of precipitation. It was observed that the Carbostar® dialysate forms a precipitate immediately after mixing with the NM solution, whereas Kindaly® and Subpac® dialysates form a precipitate after approximately 30 min. This variance is attributed to the pH adjusters used: citric acid for Carbostar®, acetic acid for Kindaly®, and hydrochloric acid for Subpac®. As trivalent negative ions, citrate ions promote faster precipitation compared to acetic acid and hydrochloric acid, which are monovalent ions. Nafamostat acetate and nafamostat chloride salts are soluble, while nafamostat citrate is poorly soluble, leading to differences in precipitation timing. The bicarbonate ion's pKa value is 6.1, meaning precipitation does not occur if the pH is lowered below 6.1 using acetic acid or hydrogen chloride as pH adjusters. The solubility product of nafamostat bicarbonate is 8.1 × 10-7 (mol/L)3, making precipitation inevitable under dialysis conditions ([nafamostat2+] = 5 mg/mL (9.2 mM), [HCO3-] = 35 mM). The primary precipitate component is nafamostat bicarbonate salt. Although NM is initially water-soluble, it undergoes chemical transformation into a poorly soluble salt through ion exchange from mesylate ions to bicarbonate ions within the dialysate, resulting in precipitation. Based on these findings, we propose conditions to avoid precipitation.

Nafamostat Mesylate Regulates Glycosylation to Alleviate Aristolochic Acid Induced Kidney Injury

Acute kidney injury (AKI) is a condition with a poor prognosis, exacerbated by the lack of effective therapeutic options and inadequately understood underlying mechanisms. Glycosylation, a post-translational modification of proteins, is essential for maintaining protein stability and function, and its dysregulation leads to protein misfolding and amyloid aggregation. Glycosylation dynamics are implicated in several pathologies, including inflammation, cancer, and AKI, highlighting the therapeutic potential of regulating glycosylation and preventing aggregation in AKI treatment. This study investigates the effect of nafamostat mesylate (NM) on protein glycosylation and amyloid aggregation in vivo. Using optical spectroscopy and other analytical techniques, we demonstrate that NM restores glycosylation levels and inhibits protein aggregation in aristolochic-acid-induced acute kidney injury. The mechanism likely involves enzymatic modulation that corrects hypoglycosylation and prevents amyloid aggregation, promoting proper protein folding and enhancing its stability. These findings suggest that NM may provide a novel therapeutic strategy for AKI and other glycosylation-related diseases, underscoring the potential for early intervention and treatment of these conditions.

The role of nafamostat mesylate anticoagulation in continuous kidney replacement therapy for critically ill patients with bleeding tendencies: a retrospective study on patient outcomes and safety

BACKGROUND

Continuous kidney replacement therapy (CKRT) is crucial in the management of acute kidney injury in intensive care units (ICUs). Nonetheless, the optimal anticoagulation strategy for patients with bleeding tendencies remains debated. This study aimed to evaluate patient outcomes and safety of nafamostat mesylate (NM) compared with no anticoagulation (NA) in critically ill patients with bleeding tendencies who were undergoing CKRT.

METHODS

This retrospective study enrolled 2,313 patients who underwent CKRT between March 2013 and December 2022 at the third affiliated hospital in South Korea. After applying the exclusion criteria, 490 patients were included in the final analysis, with 245 patients in the NM and NA groups each, following 1:1 propensity score matching. Subsequently, in-hospital mortality, incidence of bleeding complications, agranulocytosis, hyperkalemia, and length of hospital stay were assessed.

RESULTS

No significant differences were observed between the groups regarding the lengths of hospital and ICU stays or the incidence of agranulocytosis and hyperkalemia. The NM group showed a smaller decrease in hemoglobin levels during CKRT (-1.90 g/dL vs. -2.39 g/dL) and less need for blood product transfusions than the NA group. Furthermore, the NM group exhibited a survival benefit in patients who required transfusion of all three blood products.

CONCLUSION

NM is an effective and safe anticoagulant for CKRT in critically ill patients, especially those requiring transfusion of all three blood products. Although these findings are promising, further multicenter studies are needed to validate them and explore the mechanisms underlying the observed benefits.

Comparison of the cytokine adsorption ability in continuous renal replacement therapy using polyethyleneimine-coated polyacrylonitrile (AN69ST) or polymethylmethacrylate (PMMA) hemofilters: a pilot single-center open-label randomized control trial

BACKGROUND

Sepsis occurs as a result of dysregulated host response to infection. However, cytokine adsorption therapy may restore the balance of proinflammatory and anti-inflammatory mediator responses in patients with sepsis. This study aimed to determine the cytokine adsorption ability of two different types of continuous renal replacement therapy (CRRT) hemofilters for polyethyleneimine-coated polyacrylonitrile (AN69ST) (surface-treated) and polymethylmethacrylate (PMMA) CRRT.

METHODS

We performed a randomized controlled trial among sepsis patients undergoing CRRT, who were randomly assigned (1:1) to receive either AN69ST or PMMA-CRRT. The primary outcome was cytokine clearance of hemofilter adsorption (CHA). The secondary endpoints were the intensive care unit (ICU) and 28-day mortalities.

RESULTS

We randomly selected 52 patients. Primary outcome data were available for 26 patients each in the AN69ST-CRRT and PMMA-CRRT arms. The CHA of high-mobility group box 1, tumor necrosis factor, interleukin (IL)-8, monokine induced by interferon-γ, and macrophage inflammatory protein were significantly higher in the AN69ST-CRRT group than in the PMMA-CRRT group (P < 0.001, P < 0.01, P < 0.001, P < 0.001 and P < 0.001, respectively). In contrast, the CHA of IL-6 was significantly higher in the PMMA-CRRT group than in the AN69ST-CRRT group (P < 0.001). In addition, the 28-day mortality was not significantly different between the two groups (50% in AN69ST-CRRT vs. 30.8% in PMMA-CRRT, P = 0.26).

CONCLUSION

AN69ST and PMMA membranes have different cytokine CHA in patients with sepsis. Therefore, these two hemofilters may have to be used depending on the target cytokine.

TRIAL REGISTRATION NUMBER

This study was registered in the University Hospital Medical Information Network on November 1, 2017 (Trial No: UMIN000029450, https://center6.umin.ac.jp ).

Multicenter, single-blind, randomized controlled study of the efficacy and safety of favipiravir and nafamostat mesilate in patients with COVID-19 pneumonia

OBJECTIVES

To evaluate the efficacy and safety of nafamostat combined with favipiravir for the treatment of COVID-19.

METHODS

We conducted a multicenter, randomized, single-blind, placebo-controlled, parallel assignment study in hospitalized patients with mild-to-moderate COVID-19 pneumonia. Patients were randomly assigned to receive favipiravir alone (n = 24) or nafamostat with favipiravir (n = 21). The outcomes included changes in the World Health Organization clinical progression scale score, time to improvement in body temperature, and improvement in oxygen saturation (SpO₂).

RESULTS

There was no significant difference in the changes in the clinical progression scale between nafamostat with favipiravir and favipiravir alone groups (median, -0.444 vs -0.150, respectively; least-squares mean difference, -0.294; P = 0.364). The time to improvement in body temperature was significantly shorter in the combination group (5.0 days; 95% confidence interval, 4.0-7.0) than in the favipiravir group (9.0 days; 95% confidence interval, 7.0-18.0; P =0.009). The changes in SpO₂ were greater in the combination group than in the favipiravir group (0.526% vs -1.304%, respectively; least-squares mean difference, 1.831; P = 0.022). No serious adverse events or deaths were reported, but phlebitis occurred in 57.1% of the patients in the combination group.

CONCLUSION

Although our study showed no differences in clinical progression, earlier defervescence, and recovery of SpO₂ were observed in the combination group.

The role of nafamostat mesilate as a regional anticoagulant during extracorporeal membrane oxygenation

BACKGROUND

Anticoagulation during extracorporeal membrane oxygenation (ECMO) usually is required to prevent thrombosis. The aim of this study was to investigate the usefulness of nafamostat mesilate (NM) as a regional anticoagulant during veno-arterial ECMO (VA-ECMO) treatment.

METHODS

We retrospectively reviewed the medical records of 16 patients receiving VA-ECMO and NM from January 2017 to June 2020 at Haeundae Paik Hospital. We compared clinical and laboratory data, including activated partial thromboplastin time (aPTT), which was measured simultaneously in patients and the ECMO site, to estimate the efficacy of regional anticoagulation.

RESULTS

The median patient age was 68.5 years, and 56.3% of patients were men. Cardiovascular disease was the most common primary disease (75.0%) requiring ECMO treatment, followed by respiratory disease (12.5%). The median duration of ECMO treatment was 7.5 days. Among 16 patients, seven were switched to NM after first using heparin as an anticoagulation agent, and nine received only NM. When comparing aPTT values in the NM group between patients and the ECMO site, that in patients was significantly lower than that at the ECMO site (73.57 vs. 79.25 seconds; P=0.010); in contrast, no difference was observed in the heparin group.

CONCLUSIONS

NM showed efficacy as a regional anticoagulation method by sustaining a lower aPTT value compared to that measured at the ECMO site. NM should be considered as a safer regional anticoagulation method in VA-ECMO for patients at high risk of bleeding.

Reliable measurement of plasma kinin peptides: Importance of preanalytical variables

BACKGROUND

The kallikrein-kinin system is involved in many (patho)physiological processes and kinin peptides are considered potential clinical biomarkers. Variance in blood specimen collection and processing, artificial ex vivo bradykinin formation, and rapid degradation of kinins have contributed to divergence in published plasma levels, therefore limiting their significance. Thus, reliable preanalytical settings are highly required.

OBJECTIVES

This study aimed to develop and evaluate a standardized preanalytical procedure for reliable kinin quantification. The procedure was based on identification of the most impactful variables on ex vivo plasma level alterations.

METHODS

Suitable protease inhibitors and blood specimen collection and handling conditions were systematically investigated. Their influence on plasma levels of seven kinins was monitored using an established in-house liquid chromatography-tandem mass spectrometry platform.

RESULTS

In nonstandardized settings, ex vivo rise of bradykinin was found to already occur 30 seconds after blood sampling with high interindividual variation. The screening of 17 protease inhibitors resulted in a customized seven-component protease inhibitor, which efficiently stabilized ex vivo kinin levels. The reliability of kinin levels was substantially jeopardized by prolonged rest time until centrifugation, phlebotomy methodology (eg, straight needles, catheters), vacuum sampling technique, or any time delays during venipuncture. The subsequently developed standardized procedure was applied to healthy volunteers and proved it significantly limited interday and interindividual kinin level variability.

CONCLUSION

The developed procedure for blood specimen collection and handling is feasible in clinical settings and allows for determination of reliable kinin levels. It may contribute to further elucidating the role of the kallikrein-kinin system in diseases like angioedema, sepsis, or coronavirus disease 2019.

Measuring the Concentration of Serum Syndecan-1 to Assess Vascular Endothelial Glycocalyx Injury During Hemodialysis

Glycocalyx is present on the surface of healthy endothelium, and the concentration of serum syndecan-1 can serve as an injury marker. This study aimed to assess endothelial injury using serum syndecan-1 as a marker of endothelial glycocalyx injury in patients who underwent hemodialysis. In this single-center, retrospective, observational study, 145 patients who underwent hemodialysis at the Gifu University Hospital between March 2017 and December 2019 were enrolled. The median dialysis period and time were 63 months and 3.7 h, respectively. The serum syndecan-1 concentration significantly increased from 124.6 ± 107.8 ng/ml before hemodialysis to 229.0 ± 138.1 ng/ml after hemodialysis (P &lt; 0.001). Treatment with anticoagulant nafamostat mesylate inhibited hemodialysis-induced increase in the levels of serum syndecan-1 in comparison to unfractionated heparin. Dialysis time and the change in the syndecan-1 concentration were positively correlated. Conversely, the amount of body fluid removed and the changes in the syndecan-1 concentration were not significantly correlated. The reduction in the amount of body fluid removed and dialysis time inhibited the change in the syndecan-1 levels before and after hemodialysis. In conclusion, quantitative assessment of the endothelial glycocalyx injury during hemodialysis can be performed by measuring the serum syndecan-1 concentration, which may aid in the selection of appropriate anticoagulants, reduction of hemodialysis time, and the amount of body fluid removed.

Aggressive early surgical strategy in patients with intracranial hemorrhage: a new cardiopulmonary bypass option

OBJECTIVE

We present a novel strategy in cardiac surgery with a cardiopulmonary bypass with low-dose heparin and Nafamostat mesylate as an anticoagulant (NM-CPB), which reduces postoperative neurological complications.

METHOD AND RESULTS

19 patients with a mean age of 63.6 ± 20.2 years (range 24-91) and an indication of early cardiac surgery with intracranial complication (ICC) underwent surgery with NM-CPB. The preoperative diagnoses included seven cases of infective endocarditis and six of left atrial appendage thrombosis. ICC were noticed in seven cases with hemorrhages (hemorrhagic infarction: n = 4, subarachnoid hemorrhage: n = 3) and 12 without hemorrhage (large infarction: n = 10, small-multiple infarction at the risk for hemorrhagic transformation: n = 2). The mean interval between a diagnosis and cardiac surgery was 1.1 ± 1.5 days in the ICH cases and 1.4 ± 1.4 days otherwise. In-hospital mortality was 5.3%. The mean CPB time was 146.7 ± 66.03 min, the mean dose of NM, heparin were 2.23 ± 1.59 mg/kg/hr and 56.8 ± 20.3 IU/kg, respectively. The mean activated clotting time (ACT) was 426.8 ± 112.4 s. No further intracranial bleeding and no new hemorrhages were observed after surgery.

CONCLUSIONS

In early cardiac surgery with ICC, especially with hemorrhage, NM-CPB reduced postoperative neurological complications. We plan to use NM-CPB to expand the indications and to establish an early aggressive treatment.

Use of argatroban in combination with nafamostat mesilate in open-heart surgery for a pediatric patient with heparin-induced thrombocytopenia type II: a case report

Background

Heparin-induced thrombocytopenia type II (HIT II) is a rare, immune-mediated complication of heparin therapy and can cause life-threatening thromboembolism. However, perioperative anticoagulation therapy for patients with a complication of HIT II has not been established.

Case presentation

A 6-year-old boy with tetralogy of Fallot underwent radical intracardiac repair with administration of argatroban at 1 year old due to positive HIT antibody. Reoperation was scheduled for pulmonary valve insufficiency, using argatroban and nafamostat mesilate as anticoagulants. Argatroban has a long onset time and the activated coagulation time (ACT) requires 7–26 h to return to the preadministration level, making hemorrhage control difficult, while half-life of nafamostat mesilate is shorter than that of argatroban. Celite ACT reflects the effects of both argatroban and nafamostat mesilate, but kaolin ACT reflects only the effect of argatroban. Due to the early termination of argatroban administration based on Celite and kaolin ACTs, ACT recovered to ≤ 200 s at 5 h after the end of argatroban administration.

Conclusion

Celite and kaolin ACTs can be used as markers to obtain close control of the required dose of argatroban in combination with nafamostat mesilate for the management of HIT II patients.

Challenges in Maintaining the Hemostatic Balance in Children Undergoing Extracorporeal Membrane Oxygenation: A Systematic Literature Review

Background: Despite advances in technology and clinical experience, the incidence of hemostatic complications, including bleeding and thrombosis, remains high in children supported with extracorporeal membrane oxygenation (ECMO). These hemostatic complications are important to prevent, since they are associated with increased morbidity and mortality. This systematic literature review aims to outline the most important risk factors for hemostatic complications in children undergoing ECMO treatment, to summarize the reported alternative anticoagulant drugs used in pediatric ECMO and to describe studied associations between coagulation tests and hemostatic complications. Methods: A literature search was performed in Embase, Medline, Web of Science Core Collection, Cochrane Central Register of Controlled Trials, and Google Scholar in February 2020. Included studies were studies evaluating children (<18 years old) treated with ECMO, and studies evaluating risk factors for hemostatic complications, alternative anticoagulants, or the association between coagulation tests and hemostatic complications. Results: Out of 1,152 articles, 35 studies were included. Thirteen out of 49 risk factors were investigated in three or more studies. Most consistent results were found regarding ECMO duration and pH. However, evidence for risk factors was equivocal in the majority of studies, which is explained by the variability of populations studied, definitions of hemostatic complications, ECMO circuits, anticoagulation protocols, transfusion triggers and monitoring of anticoagulation. Five studies described alternative anticoagulants, including bivalirudin (n = 3), argatroban (n = 1) and FUT (n = 1). Higher anti-factor Xa levels were associated with less clotting events in one of nine studies, investigating the association between tests and hemostatic complications. Two studies revealed an association between anti-factor Xa assay-based protocols and a decreased number of transfusions, bleedings and need for circuit change. Conclusion: Studies regarding risk factors showed conflicting results and a few retrospective studies reported the use of new anticoagulants and data on coagulation tests in relation to hemostatic complications. To decrease hemostatic complications in ECMO children, prospective multicenter studies are needed with clear bleeding and thrombotic definitions, and the best possible standardization of ECMO circuits used, anticoagulation protocols, and transfusion triggers.

Comparison of gabexate mesilate and nafamostat mesilate for disseminated intravascular coagulation associated with hematological malignancies

We evaluated clinical outcomes of disseminated intravascular coagulation (DIC) in patients with hematological malignancies treated with synthetic protease inhibitors (SPIs) and compared the effects of gabexate mesilate (FOY) and nafamostat mesilate (FUT). We retrospectively examined 127 patients [acute myeloid leukemia (n = 48), acute lymphoblastic leukemia (n = 25), and non-Hodgkin lymphoma (n = 54)] with DIC, who were diagnosed according to Japanese Ministry of Health, Labour and Welfare criteria and treated with SPIs [FOY (n = 55) and FUT (n = 72)] at our hospital from 2006 to 2015. The DIC resolution rates on days 7 and 14 were 42.6% and 62.4%, respectively. No significant differences were observed in DIC resolution rates between the FUT and FOY groups [40.3% vs. 45.5% (day 7), P = 0.586; 56.3% vs. 69.8% (day 14), P = 0.179, respectively]. Multivariate analysis revealed that response to chemotherapy was the only independent predictor of DIC resolution on days 7 and 14 (ORR 2.81, 95% CI 1.32-5.98, P = 0.007; ORR 2.51, 95% CI 1.12-5.65, P = 0.026). Resolution of DIC was correlated with improvement of background hematological malignancies, and no significant differences were observed between the two SPIs.

A Synthetic Serine Protease Inhibitor, Nafamostat Mesilate, Is a Drug Potentially Applicable to the Treatment of Ebola Virus Disease

Ebola virus disease (EVD) has been a great concern worldwide because of its high mortality. EVD usually manifests with fever, diarrhea and vomiting, as well as disseminated intravascular coagulation (DIC). To date, there is neither a licensed Ebola vaccine nor a promising therapeutic agent, although clinical trials are ongoing. For replication inside the cell, Ebola virus (EBOV) must undergo the proteolytic processing of its surface glycoprotein in the endosome by proteases including cathepsin B (CatB), followed by the fusion of the viral membrane and host endosome. Thus, the proteases have been considered as potential targets for drugs against EVD. However, no protease inhibitor has been presented as effective clinical drug against it. A synthetic serine protease inhibitor, nafamostat mesilate (NM), reduced the release of CatB from the rat pancreas. Furthermore, it has anticoagulant activities, such as inhibition of the factor VIIa complex, and has been used for treating DIC in Japan. Thus, NM could be considered as a drug candidate for the treatment of DIC induced by EBOV infection, as well as for the possible CatB-related antiviral action. Moreover, the drug has a history of large-scale production and clinical use, and the issues of safety and logistics might have been cleared. We advocate in vitro and in vivo experiments using active EBOV to examine the activities of NM against the infection and the DIC induced by the infection. In addition, we suggest trials for comparison among anti-DIC drugs including the NM in EVD patients, in parallel with the experiments.

Ability of nafamostat mesilate to prolong filter patency during continuous renal replacement therapy in patients at high risk of bleeding: a randomized controlled study

Continuous renal replacement therapy (CRRT) is considered as an effective modality for renal replacement therapy in hemodynamically unstable patients within intensive care units (ICUs). However, the role of heparin anticoagulation, which is used to maintain circuit patency, is equivocal due to the risk of bleeding and morbidity. Among various alternative anticoagulants, nafamostat mesilate has been shown to be an effective anticoagulant in patients prone to bleeding. Hence, we conducted a prospective, randomized controlled study investigating the effect of nafamostat mesilate on mortality, CRRT filter life span and adverse events in patients with bleeding tendency. Seventy-three Patients were randomized into either the futhan or no-anticoagulation group. Thirty-six subjects in the futhan group received nafamostat mesilate, while thirty seven subjects in the no-anticoagulation group received no anticoagulants. Baseline characteristics and appropriate laboratory tests were taken from each group. The mortality between the two groups was not significantly different. Nevertheless, between the futhan group and the no-anticoagulation group, the overall number of filters used during CRRT (2.71 ± 2.12 vs. 4.50 ± 3.25; p = 0.042) and the number of filters changed due to clots per 24 hours (1.15 ± 0.81 vs. 1.74 ± 1.62; p = 0.040) were significantly different. When filter life span was subdivided into below and over 12 hours, the number of filters functioning over 12 hours was significantly higher in the futhan group than in the no-anticoagulation group (p = 0.037, odds ratio 1.84). There were no significant differences in transfusion, mortality, or survival between the two groups, and no adverse events related to nafamostat mesilate were noted. Hence, nafamostat mesilate may be used as an effective and safe anticoagulant, without increasing the risk of major bleeding complications, in patients prone to bleeding.

TRIAL REGISTRATION

Clinicaltrials.gov NCT01761994.

Nafamostat mesilate attenuates neuronal damage in a rat model of transient focal cerebral ischemia through thrombin inhibition

Evidence suggests that thrombin, a blood coagulation serine protease, mediates neuronal injury in experimental cerebral ischemia. Here, we test the hypothesis that nafamostat mesilate, a serine protease inhibitor, may ameliorate ischemia-induced neuronal damage through thrombin inhibition after ischemic stroke. Focal ischemia was induced in adult Sprague-Dawley rats by occlusion of the middle cerebral artery for 2 hours followed by 22 hours of reperfusion. The administration of nafamostat mesilate during ischemia and reperfusion reduced the brain infarct volume, edema volume and neurological deficit. Thrombin expression and activity in the ipsilateral striatum were increased after ischemia, whereas the administration of nafamostat mesilate significantly inhibited thrombin expression and activity. Immunostaining showed that the majority of thrombin was expressed in neurons. TUNEL staining showed that nafamostat mesilate reduced the number of dying cells during ischemia. A rat behavioral test showed that nafamostat mesilate treatment significantly improved the learning ability of ischemic rats. These results suggest that nafamostat mesilate may have a potential therapeutic role for neuroprotection against focal cerebral ischemia through thrombin inhibition.

Nafamostat mesilate: can it be used as a conduit preserving agent in coronary artery bypass surgery?

Background

Graft vessel preservation solution in coronary artery bypass surgery is used to maintain the graft conduit in optimal condition during the perioperative period. Nafamostat mesilate (NM) has anticoagulation and anti-inflammatory properties. Therefore, we investigated NM as a conduit preservative agent and compared it to papaverine.

Methods

Sprague-Dawley (SD) rat thoracic aortas were examined for their contraction-relaxation ability using phenylephrine (PE) and acetylcholine (ACh) following preincubation with papaverine and NM in standard classical organ baths. Human umbilical vein endothelial cells (HUVECs) were cultured to check for the endothelial cell viability. Histopathological examination and terminal deoxynucleotidyl transferase dUTP nick end labeling assay were performed on the thoracic aortas of SD rats.

Results

The anti-contraction effects of papaverine were superior to those of NM at PE (p<0.05). The relaxation effect of NM on ACh-induced vasodilatation was not statistically different from that of papaverine. Viability assays using HUVECs showed endothelial cell survival rates of >90% in various concentrations of both NM and papaverine. A histopathological study showed a protective effect against necrosis and apoptosis (p<0.05) in the NM group.

Conclusion

NM exhibited good vascular relaxation and a reasonable anti-vasocontraction effect with a better cell protecting effect than papaverine; therefore, we concluded that NM is a good potential conduit preserving agent.

Effect of nafamostat on N-methyl-D-aspartate-induced retinal neuronal and capillary degeneration in rats

We examined the effects of the serine protease inhibitor nafamostat mesilate on neuronal and vascular injury in rat retinas treated with N-methyl-D-aspartate (NMDA). The degree of neuronal degeneration was assessed by measuring the number of cells in the ganglion cell layer and the thickness of the inner plexiform layer. The degree of capillary degeneration was assessed by measuring the number of empty basement membrane sleeves that were left as remnants of the vessels. Significant neuronal and capillary degeneration was observed 7 d after a single intravitreal injection of NMDA into the eye. Both forms of degeneration were significantly prevented by simultaneous injection of nafamostat mesilate with NMDA. These results indicate that nafamostat mesilate affords protection against the neuro/vascular injury seen in NMDA-treated retinas. Nafamostat mesilate may be considered as a candidate for neuro/vascular protective interventions in retinal diseases associated with glutamate-induced excitotoxicity, such as glaucoma and diabetic retinopathy.

Use of nafamostat mesilate as an anticoagulant during extracorporeal membrane oxygenation

Although the incidence of bleeding complications during extracorporeal membrane oxygenator (ECMO) support has decreased in various trials, bleeding is still the most fatal complication. We investigated the ideal dosage and efficacy of nafamostat mesilate for use with ECMO in patients with acute cardiac or respiratory failure. We assessed 73 consecutive patients who received ECMO due to acute cardiac or respiratory failure between January 2006 and December 2009. To evaluate the efficacy of nafamostat mesilate, we divided the patients into 2 groups according to the anticoagulants used during ECMO support. All patients of nafamostat mesilate group were male with a mean age of 49.2 yr. Six, 3, 5, and 3 patients were diagnosed with acute myocardial infarction, cardiac arrest, septic shock, and acute respiratory distress syndrome, respectively. The mean dosage of nafamostat mesilate was 0.64 mg/kg/hr, and the mean duration of ECMO was 270.7 hr. The daily volume of transfused packed red blood cells, fresh frozen plasma, and cryoprecipitate and the number of complications related to hemorrhage and thrombosis was lower in the nafamostat mesilate group than in the heparin group. Nafamostat mesilate should be considered as an alternative anticoagulant to heparin to reduce bleeding complications during ECMO.

Pretreatment with nafamostat mesilate, a kallikrein inhibitor, to decrease withdrawal response associated with rocuronium

PURPOSE

This randomized, double-blind, placebo-controlled study was conducted to examine the preventive effect of nafamostat mesilate, a kallikrein inhibitor, on the withdrawal response associated with rocuronium injection.

METHODS

Ninety American Society of Anesthesiology (ASA) physical status I or II patients, aged 18-65 years, were randomly divided into two groups that received either a 1.5-ml solution containing 1.5 mg nafamostat mesilate diluted in a 5% glucose solution or a 1.5-ml 5% glucose solution. Anesthesia was induced by 5 mg/kg 2.5% thiopental. After confirming loss of consciousness, a tourniquet was applied to the mid forearm and tightened to block venous flow. The test solution was then administered, 1 min after which the tourniquet was removed and 0.6 mg/kg rocuronium was administered. Each patient's response to rocuronium injection was graded on a four-point scale in a double-blind manner. Activated coagulation time and plasma potassium concentration were measured before and 5 and 10 min after nafamostat administration.

RESULTS

The incidence of withdrawal response was 68.9% in the control group and 24.4% in the nafamostat group (P < 0.001). The number of patients showing generalized movement (response 4) with the rocuronium injection was significantly lower in nafamostat group [1 (2.2%)] than the control group [15 (33.3%)], P < 0.001. Five and 10 min after nafamostat administration, measured potassium and activated coagulation time were similar to baseline values.

CONCLUSION

Pretreatment with 1.5 mg nafamostat mesilate decreased withdrawal response associated with rocuronium injection.

Mechanisms of the hyperkalaemia caused by nafamostat mesilate: effects of its two metabolites on Na+ and K+ transport properties in the rabbit cortical collecting duct

1. The present experiments were undertaken to determine the mechanism(s) of hyperkalaemia caused by nafamostat mesilate (NM), a serine-protease inhibitor. 2. We investigated the effects of luminal addition of two metabolites of NM, p-guanidinobenzoic acid (PGBA) and 6-amidino-2-naphthol (AN), on Na+ and K+ transport properties of the collecting duct (CD) cell in the isolated perfused cortical collecting duct (CCD) from rabbit kidneys, because these metabolites, but not NM, were mainly excreted into the urine. 3. Addition of PGBA at 10(-5) and 10(-4) M in the lumen resulted in a hyperpolarization of VA in parallel with increases in transepithelial resistance (RT) and fractional apical membrane resistance (fRA). PGBA added to the luminal perfusate at 10(-5) and 10(-4) M changed VA, RT and fRA in a dose-dependent manner. These effects were completely inhibited by pretreatment with luminal amiloride (50 microM). PGBA at 10(-6) M in the lumen had no effect on the electrical parameters. 4. Luminal addition of AN at 10(-4) M also caused the apical membrane to hyperpolarize in parallel with increases in RT and fRA. These effects were also completely inhibited by pretreatment with luminal amiloride (50 microM). AN at 10(-5) M in the lumen had no effect on the electrical parameters. 5. We conclude that two metabolites of NM, PGBA and AN, act on the apical membrane of the CD cell and inhibit the amiloride-sensitive Na+ conductance, resulting in an inhibition of K+ secretion. This direct action of these metabolites, rather than NM, on the CCD might contribute to the NM-induced hyperkalaemia.

Effect of nafamostat mesilate on Na+ and K+ transport properties in the rabbit cortical collecting duct

1. To determine the mechanism(s) of hyperkalemia caused by nafamostat mesilate (NM), a serine-protease inhibitor, we investigated the effects of the drug on Na+ and K+ transport properties of the collecting duct (CD) cell in the isolated and perfused cortical collecting duct from rabbit kidneys. 2. NM at 10(-4) M in the lumen, hyperpolarized the apical membrane in parallel with increases in transepithelial resistance (RT) and fractional apical membrane resistance (fRA). 3. These effects were completely inhibited by pretreatment with 50 microM luminal amiloride, whereas they were not affected by luminal addition of 2 mM Ba2+. 4. NM at 10(-4) M in the bath slightly but significantly depolarized the basolateral membrane without any changes in RT or fRA, although NM at 10(-5) M in the bath had no effect on the electrical parameters. 5. It is concluded that NM mainly acts on the apical membrane of the CD cell and inhibits the amiloride-sensitive Na+ conductance in the apical membrane.

Immunoadsorbent plasmapheresis for a patient with antiphospholipid syndrome during pregnancy

The case of a 34 year old woman with systemic lupus erythematosus with a history of three previous recurrent abortions and lupus anticoagulant and anticardiolipin antibodies is reported. Immunoadsorbent plasmapheresis with a dextran sulphate column was used to remove lupus anticoagulant, anticardiolipin antibodies, and antibodies to DNA during her fourth pregnancy in combination with low doses of aspirin and prednisolone. Although during the course of treatment prednisolone was transiently increased to 30 mg/day owing to an asymptomatic increase of lupus anticoagulant and anticardiolipin antibodies, the levels of lupus anticoagulant, anticardiolipin antibodies, and antibodies to DNA were decreased by immunoadsorbent plasmapheresis and a baby girl was delivered successfully by caesarean section. Therefore, immunoadsorbent plasmapheresis with dextran sulphate seems to reduce the risk of recurrent abortion in patients with the antiphospholipid syndrome.