1,2,3-Triazole Derivatives as Novel Antifibrinolytic Drugs.

Fibrinolysis is a natural process that ensures blood fluidity through the removal of fibrin deposits. However, excessive fibrinolytic activity can lead to complications in different circumstances, such as general surgery or severe trauma. The current antifibrinolytic drugs in the market, aminocaproic acid (EACA) and tranexamic acid (TXA), require high doses repetitively to maintain their therapeutic effect. These high doses are related to a number of side effects such as headaches, nasal symptoms, or gastrointestinal discomfort and severely limit their use in patients with renal impairment. Therefore, the discovery of novel antifibrinolytics with a higher specificity and lower dosage could vastly improve the applicability of these drugs. Herein, we synthesized a total of ten compounds consisting of a combination of three key moieties: an oxadiazolone, a triazole, and a terminal amine. The IC50 of each compound was calculated in our clot lysis assays, and the best candidate (1) provided approximately a 2.5-fold improvement over the current gold standard, TXA. Molecular docking and molecular dynamics were used to perform a structure-activity relationship (SAR) analysis with the lysine binding site in the Kringle 1 domain of plasminogen. This analysis revealed that 1,2,3-triazole was crucial for the activity, enhancing the binding affinity through pi-pi stacking and polar interactions with Tyr72. The results presented in this work open the door to further investigate this new family as potential antifibrinolytic drugs.

Radio-Protective effect of aminocaproic acid in human spermatozoa.

BACKGROUND: The negative effects of ionizing radiation on organs and the reproductive system are well known and documented. Exposure to gamma radiation can lead to oligospermia, azoospermia and DNA damage. Up to date, there is no effective pharmaceutical compound for protecting the male reproductive system and sperm. OBJECTIVE: This study aimed at investigating the ability of Ɛ-aminocaproic acid (EACA) to prevent the damage of human spermatozoa and DNA induced by ionizing radiation. MATERIALS AND METHODS: Sperm samples were obtained from healthy volunteers (35 men; 31.50 ± 7.34 years old). There were four experimental groups: (1) control group (CG), (2) group exposed to maximal radiation dose 67.88 mGy (RMAX), (3) low-dose radiation (minimal) 22.62 mGy (RMIN), and (4) group treated with radiation (67.88 mGy) and EACA (dose 50 ng/mL). Sperm motility, viability, and DNA damage were assessed. RESULTS: We observed a significant decrease in total sperm motility of the RMAX group compared to CG (p < .05). Sperm viability in the RMAX group was also reduced in comparison to the control (p < .05). A significant increase in DNA fragmentation was detected in the RMAX group. The results demonstrated that the treatment of sperm with EACA led to a decrease in the fragmentation of the sperm DNA (compared to the RMAX group) (p < .05). CONCLUSION: The results indicate that EACA effectively protects human spermatozoa from DNA damage induced by ionizing radiation. Treatment of spermatozoa with EACA led to the preservation of cell motility, viability, and DNA integrity upon radiation exposure.

Enhanced Anti-Tumor Effect of Folate-Targeted FA-AMA-hyd-DOX Conjugate in a Xenograft Model of Human Breast Cancer.

Folate-aminocaproic acid-doxorubicin (FA-AMA-hyd-DOX) was firstly synthesized by our group. It was indicated that FA-AMA-hyd-DOX was pH-responsive, and had strong cytotoxicity on a folate receptor overexpressing cell line (KB cells) in vitro. The aim of our study was to further explore the potential use of FA-AMA-hyd-DOX as a new therapeutic drug for breast cancer. The cellular uptake and the antiproliferative activity of the FA-AMA-hyd-DOX in MDA-MB-231 cells were measured. Compared with DOX, FA-AMA-hyd-DOX exhibited higher targeting ability and cytotoxicity to FR-positive tumor cells. Subsequently, the tissue distribution of FA-AMA-hyd-DOX was studied, and the result confirmed that DOX modified by FA can effectively increase the selectivity of drugs in vivo. After determining the maximum tolerated dose (MTD) of FA-AMA-hyd-DOX in MDA-MB-231 tumor-bearing nude mice, the antitumor effects and the in vivo safety of FA-AMA-hyd-DOX were systematically evaluated. The data showed that FA-AMA-hyd-DOX could effectively increase the dose of DOX tolerated by tumor-bearing nude mice and significantly inhibit MDA-MB-231 tumor growth in vivo. Furthermore, FA-AMA-hyd-DOX treatment resulted in almost no obvious damage to the mice. All the positive data suggest that FA-targeted FA-AMA-hyd-DOX is a promising tumor-targeted compound for breast cancer therapy.

Ceria Nanoparticles Synthesized With Aminocaproic Acid for the Treatment of Subarachnoid Hemorrhage.

Background and Purpose- Despite early aneurysm repair and aggressive management for complications, subarachnoid hemorrhage (SAH) results in at least 25% mortality rate and 50% persistent neurological deficit. We investigated whether ceria nanoparticles which have potent antioxidative activities can protect against subarachnoid hemorrhage via attenuating fatal brain injuries. Methods- Uniform, 3 nm, water-dispersed ceria nanoparticles were prepared from short sol-gel reaction of cerium (III) ions with aminocaproic acid in aqueous phase. SAH was induced by endovascular perforation of middle cerebral artery of rats. A single dose of ceria nanoparticles (0.5 mg Ce/kg) or saline control was randomly administered intravenously at an hour post-SAH. Neuronal death, macrophage infiltration, SAH grade, and brain edema were evaluated at 72 hours. Mortality and neurological function were assessed for 14 days. Results- The obtained ceria nanoparticles with high Ce3+ to Ce4+ ratio demonstrated potent antioxidative, cytoprotective, and anti-inflammatory activities in vitro. In rodent SAH models, the severity of hemorrhage was comparable between the ceria nanoparticles- and saline-treated groups. However, ceria nanoparticles significantly reduced neuronal death, macrophage infiltration, and brain edema after SAH. Ceria nanoparticles successfully improved survival rates (88.2% in the ceria nanoparticles group versus 21.1% in the control group; P<0.001) and neurological outcomes (modified Garcia score: 12.1±0.5 in the ceria nanoparticles group versus 4.4±0.5 in the control group; P<0.001) of the animals with SAH. Conclusions- Ceria nanoparticles, totally synthesized in aqueous phase using aminocaproic acid, demonstrated promising results against SAH via potent antioxidative, neuroprotective and anti-inflammatory activities. Given the obvious limitations of current therapies for SAH, ceria nanoparticles can be a potential therapeutic agent which might result in a paradigm shift in SAH treatment.

Epsilon-aminocaproic acid prevents high glucose and insulin induced-invasiveness in MDA-MB-231 breast cancer cells, modulating the plasminogen activator system.

Obesity and type II diabetes mellitus have contributed to the increase of breast cancer incidence worldwide. High glucose concentration promotes the proliferation of metastatic cells, favoring the activation of the plasminogen/plasmin system, thus contributing to tumor progression. The efficient formation of plasmin is dependent on the binding of plasminogen to the cell surface. We studied the effect of ε-aminocaproic acid (EACA), an inhibitor of the binding of plasminogen to cell surface, on proliferation, migration, invasion, epithelial-mesenchymal transition (EMT), and plasminogen activation system, in metastatic MDA-MB-231 breast cancer cells grown in a high glucose microenvironment and treated with insulin. MDA-MB-231 cells were treated with EACA 12.5 mmol/L under high glucose 30 mmol/L (HG) and high glucose and insulin 80 nmol/L (HG-I) conditions, evaluating: cell population growth, % of viability, migratory, and invasive abilities, as well as the expression of uPA, its receptor (uPAR), and its inhibitor (PAI-1), by real-time reverse transcription-polymerase chain reaction (RT-PCR) and Western blot, MMP-2 and MMP-9 mRNAs were evaluated by RT-PCR. Markers of EMT were evaluated by Western blot. Additionally, the presence of active uPA was studied by gel zymography, using casein-plasminogen as substrates. EACA prevented the increase in cell population, migration and invasion induced by HG and insulin, which was associated with the inhibition of EMT and the attenuation of HG- and insulin-dependent expression of uPA, uPAR, PAI-1, MMP-2, MMP-9, α-enolase (ENO A), and HCAM. The interaction of plasminogen to the cell surface and plasmin formation are mediators of the prometastasic action of hyperglycemia and insulin, potentially, EACA can be employed in the prevention and as adjuvant treatment of breast tumorigenesis promoted by hyperglycemia and insulin.

Comparative effectiveness of epsilon-aminocaproic acid and tranexamic acid on postoperative bleeding following cardiac surgery during a national medication shortage.

STUDY OBJECTIVE: The aim of this study was to compare the effectiveness of epsilon-aminocaproic acid (εACA) and tranexamic acid (TXA) in contemporary clinical practice during a national medication shortage. DESIGN: A retrospective cohort study. SETTING: The study was performed in all consecutive cardiac surgery patients (n=128) admitted to the cardiac-surgical intensive care unit after surgery at a single academic center immediately before and during a national medication shortage. MEASUREMENTS: Demographic, clinical, and outcomes data were compared by descriptive statistics using χ2 and t test. Surgical drainage and transfusions were compared by multivariate linear regression for patients receiving εACA before the shortage and TXA during the shortage. MAIN RESULTS: In multivariate analysis, no statistical difference was found for surgical drain output (OR 1.10, CI 0.97-1.26, P=.460) or red blood cell transfusion requirement (OR 1.79, CI 0.79-2.73, P=.176). Patients receiving εACA were more likely to receive rescue hemostatic medications (OR 1.62, CI 1.02-2.55, P=.041). CONCLUSIONS: Substitution of εACA with TXA during a national medication shortage produced equivalent postoperative bleeding and red cell transfusions, although patients receiving εACA were more likely to require supplemental hemostatic agents.

Role of PDGF-D and PDGFR-ß in neuroinflammation in experimental ICH mice model.

OBJECTIVE: Inflammation plays a key role in the pathophysiological processes after intracerebral hemorrhage (ICH). Post-ICH macrophages infiltrate the brain and release pro-inflammatory factors (tumor necrosis factor-α), amplifying microglial activation and neutrophil infiltration. Platelet-derived growth factor receptor-ß (PDGFR-ß) is expressed on macrophages and it's activation induces the recruitment of macrophages. Platelet-derived growth factor-D (PDGF-D) is an agonist with a significantly higher affinity to the PDGFR-ß compared to another isoform of the receptor. In this study, we investigated the role of PDGF-D in the pro-inflammatory response after ICH in mice. METHODS: A blood injection model of ICH was used in eight-week old male CD1 mice (weight 30g). Some mice received an injection of plasmin or PDGF-D. Gleevec, a PDGFR inhibitor, was administered at 1, 3 or 6h post-ICH. Plasmin was administered with or without PDGF-D siRNAs mixture or scramble siRNA. A plasmin-antagonist, ε-Aminocaproic acid (EACA), was co-administrated with the blood. The effects of ICH and treatment on the brain injury and post-ICH inflammation were investigated. RESULTS: ICH resulted in the overexpression of PDGF-D, associated with the infiltration of macrophages. PDGFR-inhibition decreased ICH-induced brain injury, attenuating macrophage and neutrophil infiltration, reducing microglial activation and TNF-α production. Administration of recombinant PDGF-D induced TNF-α production, and PDGFR-inhibition attenuated it. A plasmin-antagonist suppressed PDGFR-ß activation and microglial activation. Plasmin increased PDGF-D expression, and PDGF-D inhibition reduced neutrophil infiltration. CONCLUSION: ICH-induced PDGF-D accumulation contributed to post-ICH inflammation via PDGFR activation and enhanced macrophage infiltration. The inhibition of PDGFR had an anti-inflammatory effect. Plasmin is a possible upstream effector of PDGF-D. The targeting of PDGF-D may provide a novel way to decrease brain injury after ICH.

Pharmacokinetics of ε-Aminocaproic Acid in Neonates Undergoing Cardiac Surgery with Cardiopulmonary Bypass.

BACKGROUND: Antifibrinolytic medications such as ε-aminocaproic acid (EACA) are used in pediatric heart surgery to decrease surgical bleeding and transfusion. Dosing schemes for neonates are often based on adult regimens, or are simply empiric, in part due to the lack of neonatal pharmacokinetic information. The authors sought to determine the pharmacokinetics of EACA in neonates undergoing cardiac surgery and to devise a dosing regimen for this population. METHODS: Ten neonates undergoing cardiac surgery with cardiopulmonary bypass were given EACA according to standard practice, and blood was drawn at 10 time points to determine drug concentrations. Time-concentration profiles were analyzed using nonlinear mixed effects models. Parameter estimates (standardized to a 70-kg person) were used to develop a dosing regimen intended to maintain a target concentration shown to inhibit fibrinolysis in neonatal plasma (50 mg/l). RESULTS: Pharmacokinetics were described using a two-compartment model plus an additional compartment for the cardiopulmonary bypass pump. First-order elimination was described with a clearance of 5.07 l/h × (WT/70). Simulation showed a dosing regimen with a loading dose of 40 mg/kg and an infusion of 30 mg · kg · h, with a pump prime concentration of 100 mg/l maintained plasma concentrations above 50 mg/l in 90% of neonates during cardiopulmonary bypass surgery. CONCLUSIONS: EACA clearance, expressed using allometry, is reduced in neonates compared with older children and adults. Loading dose and infusion dose are approximately half those required in children and adults.

The effects of Amicar and TXA on lumbar spine fusion in an animal model.

STUDY DESIGN: Animal model. OBJECTIVE: To determine whether aminocaproic acid (Amicar) and tranexamic acid (TXA) inhibit spine fusion volume. SUMMARY OF BACKGROUND DATA: Amicar and TXA are antifibrinolytics used to reduce perioperative bleeding. Prior in vitro data showed that antifibrinolytics reduce osteoblast bone mineralization. This study tested whether antifibrinolytics Amicar and TXA inhibit spine fusion. METHODS: Posterolateral L4-L6 fusion was performed in 50 mice, randomized into groups of 10, which received the following treatment before and after surgery: (1) saline; (2) TXA 100 mg/kg; (3) TXA 1000 mg/kg; (4) Amicar 100 mg/kg; and (5) Amicar 1000 mg/kg. High-resolution plane radiography was performed after 5 weeks and micro-CT (computed tomography) was performed at the end of the 12-week study. Radiographs were graded using the Lenke scale. Micro-CT was used to quantify fusion mass bone volume. One-way analysis of variance by ranks with Kruskal-Wallis testing was used to compare the radiographical scores. One-way analysis of variance with least significant difference post hoc testing was used to compare the micro-CT bone volume. RESULTS: The average±standard deviation bone volume/total volume (%) measured in the saline, TXA 100 mg/kg, TXA 1000 mg/kg, Amicar 100 mg/kg, and Amicar 1000 mg/kg groups were 10.8±2.3%, 9.7±2.2%, 13.4±3.2%, 15.5±5.2%, and 17.9±3.5%, respectively. There was a significant difference in the Amicar 100 mg/kg (P<0.05) and Amicar 1000 mg/kg (P<0.001) groups compared with the saline group. There was greater bone volume in the Amicar groups compared with the TXA group (P<0.001). There was more bone volume in the TXA 1000 mg/kg group compared with TXA 100 mg/kg (P<0.05) but the bone volume in neither of the TXA groups was different to saline (P=0.49). There were no between-group differences observed using plane radiographical scoring. CONCLUSION: Amicar significantly "enhanced" the fusion bone mass in a dose-dependent manner, whereas TXA did not have a significant effect on fusion compared with saline control.These data are in contrast to prior in vitro data that antifibrinolytics inhibit osteoblast bone mineralization. LEVEL OF EVIDENCE: N/A.

[Effect of epsilon-aminocaproic acid, cyclophosphamide and their combination on the growth of autochthonous sarcomas of mice induced by benzo(a)pyrene].

Antifibrinolytic drug epsilon-aminocaproic acid as a therapeutic form (5% solution in saline) was tested for antitumor activity in the autochthonous subcutaneous tumors of mice, induced by benzo (a) pyrene, in monotherapy mode (instead animals received drinking water) and in combination with cyclophosphamide, which was administered once intraperitoneally in the dose of 200 mg/kg. In the control groups, treated with drinking water and saline solution instead of water, there was no stabilization and reduction in tumor volume, while in the groups receiving epsilon-aminocaproic acid, cyclophosphamide and their combination statistically significantly in comparison with the control groups there was increased the proportion of tumors with not changed or reduced volume; epsilon-aminocaproic acid enhanced the antitumor effect of cyclophosphamide. The data obtained are for further study of the antitumor effect of epsilon-aminocaproic acid.

[A case of allergic contact dermatitis due to unit dose type purified sodium hyaluronate ophthalmic solution].

BACKGROUND: We report a patient who developed allergic contact dermatitis after using a purified sodium hyaluronate ophthalmic solution (Hyalein Mini) recognized as being extremely safe. CASE REPORT: A 67-year-old woman presented to our hospital with a chief complaint of poor visual acuity. She had dry eye, cataract and ptosis in both eyes, and underwent crystalline lens reconstruction and ptosis surgery in both eyes. Postoperatively, her dry eye showed exacerbation and she developed Sjögren's syndrome. Keratoconjunctival epithelial disorders were controllable with lacrimal punctum plugs, Hyalein Mini and 0.1% fluorometholone ophthalmic suspension. The patient, however, repeatedly developed blepharitis, and allergic contact dermatitis was diagnosed with a positive patch test to epsilon-aminocaproic acid, an excipient in Hyalein Mini. Since switching to an ophthalmic solution without epsilon-aminocaproic acid, the allergic contact dermatitis has not recurred. CONCLUSION: When the same ophthalmic solution is used for chronic disease for a long time, it should be noted that allergic contact dermatitis may develop.

Aprotinin, but not ε-aminocaproic acid and tranexamic acid, exerts neuroprotection against excitotoxic injury in an in vitro neuronal cell culture model.

OBJECTIVE: Lack of availability of aprotinin has resulted in increased clinical use of the alternative antifibrinolytic agents, ε-aminocaproic acid (EACA) and tranexamic acid (TXA), which are known to be associated with an increased risk of seizures. In contrast, aprotinin has previously been demonstrated to be neuroprotective through suppression of excitotoxicity-mediated neuronal degeneration via the extracellular plasminogen/plasmin system. This study compares the effect of antifibrinolytic agents on neuronal and mixed glial/neuronal cell cultures. METHODS: Mixed cortical cultures containing neuronal and glial cells were prepared from fetal mice and plated on a layer of confluent astrocytes from postnatal pups. A primary neuronal culture was obtained from the same gestational stage and plated in multiwall vessels. Slowly triggered excitotoxicity was induced by 24-hour exposure to 12.5 mM N-methyl-D-aspartate (NMDA). Apoptotic neuronal cell death was induced by exposure of primary neural cultures to 24 hours of serum deprivation. RESULTS: Compared with NMDA alone, no significant changes in cell death were observed for any dose of TXA or EACA in mixed cultures. Conversely, a clinical dose of aprotinin significantly reduced cell death by -31% on average. Aprotinin reduced apoptotic neuronal cell death from 75% to 37.3%, and to 34.1% at concentrations of 100 and 200 kIU/mL, respectively, and significantly decreased neuronal nuclear damage. These concentrations of aprotinin significantly inhibited caspase 9 and 3/7 activations; 250 kIU/mL aprotinin exerted maximal protection on primary cortical neurons. CONCLUSIONS: In contrast to aprotinin, EACA and TXA exert no protective effect against excitotoxic neuronal injury that can occur during cardiac surgery.

Epsilon-aminocaproic acid improves postrecirculation hemodynamics by reducing intraliver activated protein C consumption in orthotopic liver transplantation.

BACKGROUND: Activated protein C (APC) is related to regulating the inflammatory response and hemodynamic stability upon reperfusion in cardiac operations and orthotopic liver transplantation (OLT). Epsilon-aminocaproic acid (EACA) is frequently used to treat fibrinolysis during OLT. It also has inhibitory effects related to the inflammatory response. However, it remains to be determined whether EACA can attenuate intraliver APC consumption and improve hemodynamic stability after reperfusion during OLT. METHODS: Fifty-nine recipients were randomized to receive either EACA (150 mg kg(-1) given intravenously prior to incision, followed by 15 mg kg(-1) h(-1) infusion until 2 h after the graft reperfusion) or the same volume of saline. Blood samples to assess plasma APC and protein C were obtained immediately before and after reperfusion from the inferior caval effluent or the portal veins for calculation of transliver differences (Δ). Hemodynamics and vasoactive medication use during the reperfusion period were observed in both groups. RESULTS: No transhepatic changes in protein C were found in either group. Immediately after reperfusion, a marked intraliver consumption of APC was noted in all recipients (P < 0.001), and intraliver consumption of APC in the control group was greater than that in the EACA-treated group (P < 0.05). Fewer requirements for vasoactive medication use after reperfusion and better initial graft function were noted in the EACA-treated group (P < 0.05). CONCLUSIONS: EACA can attenuate intraliver APC consumption and improve hemodynamic stability after reperfusion and initial graft function during OLT.

Effect of short peptides containing lysine and epsilon-aminocaproic acid on fibrinolytic activity of plasmin and topoisomerase II action on supercoiled DNA.

Effects of eight short peptides containing lysine and epsilon-aminocaproic acid (EACA) on prolongation of the clot lysis time, as well as hemolytic and antibacterial activities were investigated. Interaction with plasmids pBR322 and pUC19 with the use of ethidium bromide assay and determination of influence on the activity of topoisomerase I and II were also tested. Examined compounds inhibited fibrinolytic activity of plasmin and five of them were more active than EACA. Amides of dipeptides were most active antifibrinolytics (IC50 < 0.2 mM). According to the obtained data, the significant inhibition of fibrinolytic activity of plasmin was not associated with hemolytic effects. Examined compounds did not show antibacterial activity (MIC > 512 mg/L). DNA binding effects determined with the use of ethidium bromide were weak for all peptides and similar to those observed with EACA. Six compounds inhibited topoisomerase II action on supercoiled DNA.

Tranexamic acid concentrations associated with human seizures inhibit glycine receptors.

Antifibrinolytic drugs are widely used to reduce blood loss during surgery. One serious adverse effect of these drugs is convulsive seizures; however, the mechanisms underlying such seizures remain poorly understood. The antifibrinolytic drugs tranexamic acid (TXA) and ε-aminocaproic acid (EACA) are structurally similar to the inhibitory neurotransmitter glycine. Since reduced function of glycine receptors causes seizures, we hypothesized that TXA and EACA inhibit the activity of glycine receptors. Here we demonstrate that TXA and EACA are competitive antagonists of glycine receptors in mice. We also showed that the general anesthetic isoflurane, and to a lesser extent propofol, reverses TXA inhibition of glycine receptor-mediated current, suggesting that these drugs could potentially be used to treat TXA-induced seizures. Finally, we measured the concentration of TXA in the cerebrospinal fluid (CSF) of patients undergoing major cardiovascular surgery. Surprisingly, peak TXA concentration in the CSF occurred after termination of drug infusion and in one patient coincided with the onset of seizures. Collectively, these results show that concentrations of TXA equivalent to those measured in the CSF of patients inhibited glycine receptors. Furthermore, isoflurane or propofol may prevent or reverse TXA-induced seizures.

Peptidylarginine deiminase modulates the physiological roles of enolase via citrullination: links between altered multifunction of enolase and neurodegenerative diseases.

The citrullination of enolase by PAD (peptidylarginine deiminase) has emerged as an important post-translational modification in human disorders; however, the physiological function of citrullination remains unknown. In the present study, we report that citrullination diversely regulates the biological functions of ENO1 (α-enolase) and NSE (neuron-specific enolase). We developed three mouse IgG1 monoclonal antibodies with specificity to the following: (i) citrullination of Arg9 of ENO1 [ENO1Cit9; anti-CE1 (citrullinated enolase 1) antibody]; (ii) citrullination of Arg9 in ENO1 and NSE (ENO1Cit9/NSECit9; anti-CE1/2 antibody); and (iii) citrullination of Arg429 of NSE (NSECit429; anti-CE2 antibody). Regardless of the total protein expression level, the levels of ENO1Cit9 and NSECit429 were elevated, and their immunoreactivities were also increased in cortical neuronal cells or around blood vessels in the frontal cortex of patients with sporadic Creutzfeldt-Jakob disease and Alzheimer's disease compared with controls. In a time- and dose-dependent manner, PAD negatively regulated enolase activity via citrullination, and enolase in diseased patients was more inactive than in controls. Interestingly, the citrullination of enolase effectively promoted its proteolytic degradation by Ca2+-dependent calpain-1, and leupeptin (calpain inhibitor I) abrogated this degradation. Surprisingly, using an affinity assay, the citrullination of enolase enhanced its plasminogen-binding affinity, which was blocked by the lysine analogue ϵ-aminocaproic acid. These findings suggest that PAD-mediated citrullination regulates the diverse physiological activities of enolase and that CE may be a candidate diagnostic/prognostic factor for degenerative diseases.

Investigation of substituted 6-aminohexanoates as skin penetration enhancers.

Skin penetration enhancers are compounds used to facilitate the transdermal delivery of drugs that are otherwise not sufficiently permeable. Through a synthetic route implementing two series of esters, we generated transdermal penetration enhancers by a multi-step reaction with substituted 6-aminohexanoic acid. We present the synthesis of all newly prepared compounds here with structural confirmation accomplished by (1)H NMR, (13)C NMR, IR and mass spectroscopy (MS). The lipophilicity (logk) of all compounds was determined via RP-HPLC and their hydrophobicity (logP/ClogP) was also calculated using two commercially available programs. Ab initio calculations of geometry and molecular dynamic simulations were employed to investigate the 3-dimensional structures of selected compounds. The transdermal penetration-enhancing activity of all the synthesized esters were examined in vitro and demonstrated higher enhancement ratios than oleic acid. Compounds 2e (C(10) ester chain) and 2f (C(11) ester chain) exhibited the highest enhancement ratios. It can be concluded that the series non-substituted at the C((2)) position by a ω-lactam ring showed significantly higher activity than those with azepan-2-one. None of the prepared compounds penetrated through the skin. All of the investigated agents demonstrated minimal anti-proliferative activity using the SK-N-MC neuroepithelioma cell line (IC(50)>6.25µM), suggesting these analogs would have a low cytotoxic profile when administered in vivo as chemical penetration enhancers. The correlation between the chemical structure of the studied compounds and their lipophilicity is discussed in regards to transdermal penetration-enhancing activity.

The effect of ε-aminocaproyl-S-benzyl-L-cysteine on the t-PA activity of human saliva.

PURPOSE: The aim of this work was to study the effect of the synthetic antifibrinolytics: ε-aminocaproic acid (EACA), tranexamic acid (AMCHA) and ε-aminocaproyl-S-benzyl-L-cysteine (H-EACA-S-Bzl-L-Cys-OH) on the fibrinolytic activity of saliva in order to obtain new data on the activity of saliva tissue plasminogen activator (t-PA). MATERIAL AND METHODS: Saliva samples were obtained from healthy volunteers. Saliva, precipitate and supernatant were tested 1hr, 4 hrs and 6hrs after collection. The effect of the synthetic antifibrinolytics was examined with the use of the clot lysis time determination. RESULTS: All examined compounds inhibited the fibrinolytic activity of saliva 1hr after collection. H-EACA-S-Bzl-L-Cys-OH was the most active inhibitor. After 6 hours in room temperature only this compound showed a certain possibility to prolong the clot lysis time. CONCLUSIONS: The obtained results may indicate the possibility of the difference in specificity between the activities of t-PA of saliva and recombinant tissue plasminogen activator activities. It may explain the unexpected high inhibitory activity of H-EACA-S-Bzl-L-Cys-OH in our study.

Induction of the fibrinolytic system by cartilage extract mediates its antiangiogenic effect in mouse glioma.

Both the antiangiogenic and antitumoral activity of shark cartilage extracts (SCE) have been demonstrated in animal models and clinical trials. Studies reported that SCE induces the expression of tissue plasminogen activator gene (PLAT) in endothelial cells and increases the activity of the protein (t-PA) in vitro. The aim of this study was to demonstrate the crucial role of t-PA induction in the antiangiogenic and antitumor activity of SCE in experimental glioma. This study showed antiangiogenic and antitumoral effects of SCE in three mice glioma models (C6, HGD and GL26). Histological examination suggested perivascular proteolysis and edema as well as important intratumoral necrosis, which artefactually increased the tumor volume at high doses. Thus, the antiangiogenic effect of SCE correlated with the presence of t-PA and angiostatin in degenerating vessels. Functional in vivo experiments were conducted to modulate the plasminogen pathway. No antiangiogenic effect was observed on tumors overexpressing the plasminogen activator inhibitor-1 (PAI-1). Moreover, therapeutical effects were neutralized in mice that were cotreated with ε-aminocaproic acid (EACA, 120 mg/kg p.o.), an inhibitor that blocks the high-affinity lysine binding sites of both plasminogen and plasmin. In contrast, cotreatment with N-acetylcysteine (NAC, 7,5mg/kg i.p.), a sulfhydril donor that reduces plasmin into angiostatin or other antiangiogenic fragments, increased the benefit of SCE on mice survival. In subcutaneous models, NAC prevented the increase in tumor volume caused by high doses of cartilage extract. In conclusion, this study indicates that induction of t-PA by shark cartilage extract plays an essential role in its antiangiogenic activity, but that control of excessive proteolysis by a plasmin reductor could prevent edema and uncover the full benefit of shark cartilage extract in the treatment of intracranial tumors.

Re-evaluation of the role of antifibrinolytic therapy with lysine analogs during cardiac surgery in the post aprotinin era.

PURPOSE OF REVIEW: Hemorrhage, transfusions and the need for re-exploration can have a detrimental effect on patient outcome in cardiac surgery. With the suspension of aprotinin from the market, only the antifibrinolytics tranexamic acid and epsilon-aminocaproic acid (EACA) are left as pharmacological options to reduce hemostatic activation and associated bleeding complications. In light of the aprotinin story, the need for large independent safety studies has become evident. The current review will focus on the question of how far the quality of available data allows for judging these agents with regard to safety and efficacy, as well as whether or not new trails are warranted. RECENT FINDINGS: Both, tranexamic acid and EACA are effective in reducing blood loss and transfusion requirements in cardiac surgery. Analysis of data is complicated as the dosing scheme, especially for tranexamic acid, varies extremely and the agents are highly overdosed in most relevant trials. Newer data indicates that in a dose-dependent fashion, tranexamic acid is associated with an increase of adverse events, particularly the observation of seizures. In these studies, however, tranexamic acid has also been highly overdosed. SUMMARY: The lysine analogs are unspecific enzyme inhibitors. Therefore, it is conceivable that an overdosing might reveal severe clinical side-effects beyond the inhibition of plasmin. Further studies re-evaluating the drug safety of tranexamic acid and EACA using the recommended and approved doses are necessary.