Analysis of blood clotting with the total thrombus analysis system in healthy dogs.

To date, coagulation tests are unable to reflect in vivo coagulation status in the same system, including platelet function, fibrin clot formation, and whole blood flow. The Total Thrombus Analysis System (T-TAS), which is a microfluidic assay that simulates conditions in vivo, measures whole blood flow at defined shear rates under conditions designed to assess platelet function (PL-chip) or coagulation and fibrin clot formation (AR-chip). The T-TAS records occlusion start time, occlusion time, and area under the curve. We evaluated this test in healthy control dogs. We also investigated the effect in vivo of acetylsalicylic acid (ASA), and the effect in vitro of an anticoagulation drug (dalteparin; low-molecular-weight heparin; LMWH). The CV of the AUC of both chips was good (CVs of 6.45% [PL] and 1.57% [AR]). The inhibition of platelet function by ASA was evident in the right-shift in the PL test pressure curve. The right-shift in the AR test pressure curves showed that the administration of LMWH inhibited both platelets and the coagulation cascade. The T-TAS may be useful in the evaluation of canine blood coagulation.

The antithrombin binding regions of heparin mediate fetal growth and reduced placental damage in the RUPP model of preeclampsia†.

Preeclampsia is a serious hypertensive disorder of pregnancy, which is only cured with delivery of the placenta, thereby commonly necessitating preterm birth of the fetus. Low-molecular-weight heparin (LMWH) has demonstrated potential to reduce the incidence of preeclampsia in high-risk pregnant women, although the underlying mechanism by which LMWH protects against preeclampsia is unknown. Given the complex structure and biologic actions of heparin, we tested the hypothesis that heparin can mediate preeclampsia prevention via nonanticoagulant pathways. We compared the effects of a nonanticoagulant, glycol-split LMWH (gsHep)-rendered nonanticoagulant through disruption of the antithrombin binding regions-with the LMWH dalteparin in the rat reduced uterine perfusion pressure (RUPP) surgical model of preeclampsia. Although RUPP animals exhibit significantly elevated blood pressure and reduced plasma levels of placental growth factor (PGF) compared to sham, neither dalteparin nor gsHep treatment significantly impacted these parameters. However, the observed positive correlation between PGF levels and number of viable fetuses in RUPP-induced animals suggests that reduced PGF levels were predominately due to placental loss. Daily subcutaneous injections of low-dose dalteparin but not gsHep significantly restored fetal growth that was impaired by RUPP surgery. Placentas from RUPP animals exhibited an abnormal labyrinth structure, characterized by expanded sinusoidal blood spaces, relative to sham-operated animals. Morphometric analysis demonstrated that dalteparin but not gsHep treatment normalized development of the labyrinth in RUPP-exposed conceptuses. These data suggest that the antithrombin-binding regions of LMWH are required to confer its protective effects on fetal growth and placental development.

Role of dalteparin sodium on the growth of cancer cells and tumor-associated angiogenesis in A549 human lung cancer cell line and grafted mouse model.

PURPOSE: To investigate the effects of dalteparin sodium on the expression of vascular endothelial growth factor (VEGF), VEGF receptor (VEGFR), and hypoxia-inducible factor 1α (HIF-1α) in A549 human lung cancer (LC) cell line and a human A549-grafted nude mouse model. MATERIALS AND METHODS: A549 human lung adenocarcinoma cell line was divided into control group, treated using normal saline (NS); and dalteparin sodium groups, receiving 5, 15, 50, and 150 IU/ml of dalteparin sodium, respectively. Human A549-grafted nude mouse was induced through subcutaneous (SC) injection of A549 (5 × 106/0.2 ml) into the right armpit, and randomly assigned into control group (n = 6) receiving intraperitoneal (i.p.) injection of NS, cisplatin (DDP) group (n = 6, 3 mg/kg DDP alone, i.p., for 3 days), low molecular weight heparin (LMWH) group (n = 6) receiving SC injection of 1500 IU/kg dalteparin sodium for 35 days, and DDP plus LMWH group (n = 6, 3 mg/kg DDP, i.p., for 3 days, followed by SC injection of 1500 IU/kg dalteparin sodium for 35 days). RESULTS: Significant difference was noted in the messenger RNA expression of VEGF, VEGFR, and HIF-1α after treating with heparin with a concentration of 15, 50, or 150 IU/ml in the A549 cell line at 24 and 48 h, respectively. In the human A549-grafted nude mouse model, a significant reduction was noted in the expression of VEGF, VEGFR, and HIF-1α in the tumor mass harvested from the mice receiving administration of dalteparin sodium plus DDP. CONCLUSION: Dalteparin sodium had the inhibitory effects on the growth of human LC A549 cells in vitro and A549 LC xenograft model, which could be enhanced when administrated together with DDP.

FGF-2-containing dalteparin/protamine nanoparticles (FGF-2&D/P NPs) ameliorate UV-induced skin photoaging in hairless mice.

UVB exposure penetrates deeply into the dermis to alter skin barrier function, which is a primary factor in skin photoaging. We previously reported that dalteparin and protamine nanoparticles (D/P NPs) are effective carriers of FGF-2. This study aimed to examine the ability of FGF-2-containing D/P NPs (FGF-2&D/P NPs) to ameliorate UVB-induced skin photoaging in hairless mice. Dorsal skin of HR-1 hairless mice were exposed to UVB irradiation 5 days/week for 8 weeks (UV (+): final total, 2700 mJ/cm2). Mice were divided into four groups: Non-UVB (UV (-)) + saline, UV (+) + saline, UV (+) + FGF-2&D/P NPs, UV (+) + FGF-2, and UV (+) + D/P NPs, and following UVB irradiation, FGF-2&D/P NPs, FGF-2, and D/P NPs were applied to the groups of mice just after each UVB irradiation. Each group was subjected to evaluation of skin changes (elasticity), and histological examination using hematoxylin & eosin and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining. UVB irradiation of mice significantly induced a decline in elasticity and acanthosis, which was alleviated by application of FGF-2&D/P NPs. Furthermore, TUNEL-staining showed the proportions of apoptotic dermal fibroblast cells (DFCs) and epidermal keratinocyte cells (EKCs) in the UV (+) + FGF-2&D/P NPs group were significantly lower than those in the UV (+) + saline, UV (+) + FGF-2, and UV (+) + D/P NPs groups. Thus, FGF-2&D/P NPs may be effective in preventing skin photoaging accelerated by UVB irradiation such as declining elasticity, acanthosis, and apoptosis of DFCs and EKCs.

Effects of glycol-split low molecular weight heparin on placental, endothelial, and anti-inflammatory pathways relevant to preeclampsia.

Low molecular weight heparin (LMWH) is being investigated as a potential preventative therapy against preeclampsia. There is evidence suggesting that LMWH may prevent preeclampsia through anticoagulation-independent mechanisms. In this study, we compared the in vitro placental, endothelial, and anti-inflammatory effects of an LMWH (dalteparin) with a nonanticoagulant, glycol-split heparin derivative (gsHep). In contrast with dalteparin, gsHep did not interact with antithrombin III, possess significant anti-Factor Xa activity, or significantly prolong in vitro plasma clotting time. However, dalteparin and gsHep were otherwise mechanistically similar, both interacting with soluble fms-like tyrosine kinase-1 (sFlt1) and promoting release of the pro-angiogenic protein placental growth factor, but not the antiangiogenic sFlt1, from healthy placental villous explants. Placental explant media pretreated with dalteparin or gsHep significantly stimulated endothelial cell tube formation compared to untreated explants. Lastly, dalteparin and gsHep both significantly suppressed inflammation by inhibiting complement activation and leukocyte adhesion to endothelial cells that were activated using serum from preeclamptic women. Our data suggest that nonanticoagulant heparin derivatives may be utilized as a tool to distinguish the anticoagulation-independent mechanisms of LMWH, and provide insight into the role of anticoagulation in the prevention of preeclampsia.

Stability of Dalteparin 1,000 Unit/mL in 0.9% Sodium Chloride for Injection in Polypropylene Syringes.

The stability of dalteparin 1,000 units/mL in 0.9% sodium chloride for injection stored in polypropylene syringes under refrigeration was examined. Dalteparin 1,000-units/mL syringes were prepared by adding 9 mL of 0.9% sodium chloride for injection to 1 mL of dalteparin sodium 10,000 unit/mL from commercial single-use syringes. Compounded solutions in 0.5-mL aliquots were transferred to 1-mL polypropylene syringes and sealed with a Luer lock tip cap and stored at refrigerated temperatures (2°C to 8°C) with ambient fluorescent light exposure. Syringes from three batches of dalteparin 1,000 units/mL were potency tested in duplicate by a stability-indicating high-performance liquid chromatography assay using a 0.5-mL sample at specified intervals. Visual and pH testing were performed on each batch. Samples were visually inspected for container integrity, color, and clarity. Samples for pH testing were prepared using a 1:1 dilution of dalteparin 1,000 units/mL in sterile water for injection and underwent duplicate analysis at each time point. High-performance liquid chromatography analyses showed a remaining percent of the initial dalteparin content at day 30 of 94.88% ± 2.11%. Samples remained colorless and clear with no signs of container compromise and no visual particulate matter at each time point. Throughout the 30-day study period, pH values remained within 0.3-pH units from the initial value of 5.84. Dalteparin 1,000 unit/mL in 0.9% sodium chloride for injection, packaged in 1-mL polypropylene syringes was stable for at least 30 days while stored at refrigerated conditions with ambient fluorescent light exposure.

In vitro effects of dalteparin on thrombin generation in canine plasma.

BACKGROUND: The calibrated automated thrombogram (CAT) is a functional thrombin generation (TG) assay that may provide a new approach for monitoring anticoagulant therapy in dogs. The effects of dalteparin on TG variables in dogs are unknown. OBJECTIVES: Objectives were to establish normal TG variable ranges in dogs and measure the in vitro TG variables in canine pooled platelet-poor plasma (PPP) spiked with different dalteparin concentrations. METHODS: In the first experiment, plasma samples from 25 adult healthy Beagle dogs and 11 client-owned healthy dogs of multiple breeds was measured individually for obtaining normal TG values. In the second experiment, separate pools of the remaining PPP from 24 of the 25 previous adult Beagles and from 45 different client-owned dogs were spiked with dalteparin at 9 concentrations with increasing anti-factor Xa (anti-FXa) activity. Activated partial thromboplastin time, tissue factor-induced TG, and anti-FXa activity were measured for each concentration. Concentration-response relationships were determined with ADAPT v.5, using various nonlinear regression models for stimulatory or inhibitory effects. RESULTS: Thrombin generation ranges of client-owned dogs and Beagles were equivalent only for time-to-peak (P < .05). In vitro dalteparin resulted in a concentration-dependent decrease in endogenous thrombin potential (ETP) in pooled PPP. The estimated dalteparin concentration that produced half the maximal inhibition of baseline ETP (IC50 ) was 0.289 U/mL. Thrombin generation and anti-FXa activity were more sensitive than APTT to detect the effects of dalteparin. CONCLUSIONS: The CAT assay can measure the effects of dalteparin in canine plasma, resulting in significant dose-dependent decreases in ETP, prompting further in vivo investigation.

Effect of dalteparin administration on thrombin generation kinetics in healthy dogs.

BACKGROUND: Dalteparin is used to prevent thrombotic complications in dogs. Measurement of anti-factor Xa (anti-FXa) activity is currently used for monitoring therapy, but remains a nonfunctional test. The calibrated automated thrombogram (CAT) could be a suitable approach for functional monitoring. OBJECTIVES: We hypothesized that the CAT will detect decreased endogenous thrombin potential (ETP) in healthy dogs receiving dalteparin. METHODS: Twenty-four healthy adult Beagles were randomly allocated to 4 equal groups. A single subcutaneous (SC) dose of 50 U/kg, 100 U/kg, or 150 U/kg of dalteparin was given. Platelet-poor plasma (PPP) was collected over a 24-hour period and evaluated by thrombin generation (TG) via CAT, anti-FXa activity, and APTT. Analysis was performed with a repeated-measures general linear mixed model, and the treated groups were compared to a placebo group. RESULTS: Time, dose, and time-dose interaction significantly affected ETP (P < .0001 for all effects), peak (P < .0001 for all effects), rate index (P < .0006 for all effects), and anti-FXa activity (P < .0001 for all effects). No significant time trend was detected in the control group. Dogs receiving the 100 U/kg dalteparin SC injection showed the most homogeneous response of ETP inhibition among treated groups. The % inhibition of ETP from baseline increased nonlinearly as a function of anti-FXa activity (r2 = .8186). CONCLUSIONS: The CAT assay can be employed to measure the effects of dalteparin at different doses in healthy dogs, showing sensitivity to time- and dose-dependent changes in ETP and other TG variables. Further investigation of the CAT as a tool for monitoring low molecular weight heparin therapy in dogs is warranted.

Analysis of contributing factors influencing thromboembolic events after total knee arthroplasty.

BACKGROUND: Venous thromboembolic events (VTE) are a known and well-described complication following total knee arthroplasty (TKA). We sought to validate the American College of Chest Physicians thromboprophylaxis recommendations after elective TKA, paying special attention to our dose adjustments for weight, and their impact on VTE in our population. METHODS: We retrospectively investigated risk factors in patients undergoing TKA, focusing mainly on symptomatic VTE occurrence rates from deep vein thrombosis (DVT) or pulmonary embolism (PE). The anticoagulation protocol consisted of starting low molecular-weight heparin (LMWH) therapy, with dalteparin administered 12 h after surgery in patients who received general anesthesia or 24 h later in patients who received single-dose regional anesthesia. RESULTS: Data from 346 patients (mean age 66.8 [range 24-91] yr) who underwent primary or revision TKA depicted an overall symptomatic VTE rate of 15%. The proximal DVT rate was 1.7%, and the nonfatal PE rate was 0.9%. The mean time to VTE diagnosis was 5.6 days. The first dalteparin dose was administered 19.5 (range 10-48) h after surgery in patients without VTE and 22.6 (range 11.5-52) h after surgery in patients with VTE (p = 0.003). With a first dose of dalteparin administered 12 h postoperatively, patients presented significantly lower DVT and PE rates than if it was administered 24 h postoperatively (8.5% v. 16.3%, p = 0.048). CONCLUSION: Delayed administration of LMWH has deleteriously impacted the VTE rate after TKA at our institution. Prompt initiation of LMWH (≤ 12 h after surgery) is appropriate, without increasing the risk of major bleeding.

CONTEXTE: Les événements thromboemboliques veineux (ETV) sont une complication connue et bien décrite de la chirurgie pour prothèse totale du genou (PTG). Nous avons voulu valider les recommandations de l'American College of Chest Physicians en matière de thromboprophylaxie après la PTG non urgente en portant une attention particulière à l'ajustement des doses selon le poids et à leur impact sur les ETV dans notre population. MÉTHODES: Nous avons analysé de manière rétrospective les facteurs de risque chez des patients soumis à une PTG en nous attardant principalement aux taux d'ETV symptomatiques sous forme de thrombose veineuse profonde (TVP) ou d'embolie pulmonaire (EP). Le protocole d'anticoagulothérapie prévoyait l'administration d'une héparine de bas poids moléculaire (HBPM), la daltéparine, 12 h après la chirurgie chez les patients ayant reçu une anesthésie générale, ou 24 h après chez les patients ayant reçu une anesthésie locorégionale à dose unique. RÉSULTATS: Les données provenant de 346 patients (âgés en moyenne de 66,8 and [éventail 24-91 and]) ayant subi une PTG primaire ou une révision de PTG ont révélé un taux d'ETV symptomatique global de 15 %. Le taux de TVP proximal a été de 1,7 % et le taux d'EP non fatale a été de 0,9 %. Le temps moyen avant le diagnostic d'ETV a été 5,6 jours. La première dose de daltéparine avait été administrée 19,5 h (éventail 10-48 h) après la chirurgie chez les patients n'ayant pas présenté d'ETV et 22,6 h (éventail 11,5-52 h) après la chirurgie chez les patients ayant manifesté un ETV (p = 0,003). Avec une première dose de daltéparine administrée 12 h après l'intervention, les patients ont présenté des taux de TVP et d'EP significativement moindres que si elle leur avait été administrée 24 h après l'intervention (8,5 % c. 16,3 %, p = 0,048). CONCLUSION: L'administration retardée de l'HBPM a produit des effets défavorables pour ce qui est des taux d'ETV après la PTG dans notre établissement. L'instauration rapide de l'HBPM (≤ 12 h après la chirurgie) est appropriée et n'accroît pas le risque d'hémorragie majeure.

Dalteparin or vitamin K antagonists to prevent recurrent venous thromboembolism in cancer patients: a patient-level economic analysis for France and Austria.

BACKGROUND: International guidelines recommend extended duration secondary prophylaxis in cancer patients who develop primary venous thromboembolism (VTE). Agent selection is guided in part by one large randomized trial (i.e., CLOT; Lee et al., N Engl J Med 349:146-53, 2003) which demonstrated that dalteparin reduced the relative risk of recurrence by 52% compared with oral vitamin K antagonists (VKA; HR = 0.48, 95% CI, 0.30 to 0.77). In a subgroup analysis from that same trial, patients with renal impairment also derived benefit with dalteparin (VTE rates = 3% vs. 17%; p = 0.011). To measure the economic value of secondary VTE prophylaxis with dalteparin, a patient-level pharmacoeconomic analysis was conducted from the Austrian and French healthcare system perspectives. METHODS: Chapter 1 Healthcare resource use collected during the CLOT trial was extracted and converted into direct cost estimates. Incremental cost differences between the dalteparin and VKA groups were then combined with health state utilities to measure the cost per quality-adjusted life year (QALY) gained. RESULTS: The dalteparin group had significantly higher costs than the VKA group in both countries (Austria: dalteparin = €2687 vs. VKA = €2012; France: dalteparin = €2053 vs. VKA = €1352: p < 0.001). However, when the incremental costs were combined with the utility gain, dalteparin had a cost of €6600 and €4900 per QALY gained in Austria and France, respectively. The analyses in patients with renal impairment suggested an even better economic profile, with the cost per QALY gained being less than €4000 in both countries. CONCLUSIONS: Secondary prophylaxis with dalteparin is a cost-effective alternative to VKA for the prevention of recurrent VTE in patients with cancer.

Evaluation of an oral direct factor Xa inhibitor anticoagulant in healthy adult horses.

OBJECTIVE: To assess whether an oral direct factor Xa inhibitor (DiXaI) anticoagulant drug used at the low end of the recommended dose in people achieves presumed prophylactic plasma concentrations and does not induce bleeding in horses. DESIGN: Experimental study. SETTING: Field study. ANIMALS: Ten healthy adult horses. INTERVENTIONS: A DiXaI was administered at a dose of 0.125 mg/kg every 24 h orally for 4 days. Following a wash-out period of 2 weeks, 8 of 10 horses received daily subcutaneous doses of a low molecular weight heparin (dalteparin) for 4 consecutive days at 50 IU/kg. In both trials, antifactor Xa activity was measured at baseline time and 3 hours after each dose administration. Activated partial thromboplastin time, prothrombin time, hematocrit, erythrocyte agglutination, and platelet aggregation were monitored throughout the study. In addition, an in vitro spiking experiment was performed to demonstrate anticoagulant activity of this DiXaI in horse plasma. MAIN RESULTS: When treated with the DiXaI, this group of horses did not achieve the suggested thromboprophylactic plasma range of antifactor Xa activity (0.1-0.2 IU/mL), except for 1 horse after the first administration of the drug. In contrast, median values of plasma antifactor Xa activity 3 hours after receiving dalteparin were within the prophylactic range (0.16 IU/mL). No hemorrhagic events or erythrocyte agglutination were observed. In vitro addition of this DiXaI caused a concentration-dependent effect in antifactor Xa activity. CONCLUSIONS: At the low end of the recommended dose in people this oral formulation of DiXaI did not reach prophylactic plasma antifactor Xa activity in this group of healthy adult horses. Further studies are warranted in order to establish the prophylactic dose for horses.

The effect of dalteparin on thromboelastography in pregnancy: an in vitro study.

BACKGROUND: Dalteparin is often used for prophylaxis or treatment of venous thromboembolism during pregnancy, yet there is no laboratory test to accurately reflect its clinical activity. Thromboelastography is a point-of-care monitor of whole blood coagulation. The aim of this study was to determine if serial doses of dalteparin added in vitro to whole blood samples from term, pregnant women are detectable as changes in thromboelastography parameters. METHODS: Thirty healthy parturients presenting for elective caesarean section were recruited. Dalteparin was added to whole blood samples to yield final concentrations of 0 (control), 0.05, 0.25, 0.5, 0.75 and 1.0U/mL anti-Xa activity. Thromboelastography tracings were obtained for all six samples using the standard kaolin protocol. RESULTS: Significant differences were noted in median thromboelastography r time, k time, alpha angle and maximal amplitude between non-anticoagulated (⩽0.05U/mL) and samples ⩾0.5U/mL (P<0.05). The r time and k time presented with the highest sensitivities of 97.5 and 84.0, respectively. CONCLUSION: This pilot study provides proof-of-concept that thromboelastography can discriminate differences in blood anticoagulated with varying doses of dalteparin in a dose-dependent manner. This suggests that thromboelastography may be a feasible monitor of anticoagulation in the presence of dalteparin in maternal whole blood and may potentially translate to a point-of-care test that can be used to determine real-time coagulation status in patients.

Assessment of the effects of dalteparin on coagulation variables and determination of a treatment schedule for use in cats.

OBJECTIVE To determine a treatment protocol for SC administration of dalteparin to cats on the basis of currently available detailed pharmacokinetic data and to assess the effect of SC administration of dalteparin to cats on coagulation variables such as activated partial thromboplastin time (aPTT), thrombin time, and results for thromboelastometry, compared with effects on anti-activated coagulation factor X (anti-Xa) activity. ANIMALS 6 healthy domestic shorthair cats. PROCEDURES Cats received 14 injections of dalteparin (75 anti-Xa U/kg, SC) at 6-hour intervals. Blood samples were collected before and 2 hours after the first and second injections on days 1, 2, and 4. Anti-Xa activity was measured by use of a chromogenic substrate assay, aPTT and thrombin time were measured by use of an automated coagulometer, and viscoelastic measurements were obtained with thromboelastrometry. RESULTS 2 hours after the second injection, the target peak anti-Xa activity range of 0.5 to 1.0 U/mL was achieved in all cats, whereas median trough values remained below this range. Peak anti-Xa activity had only minimal effects on coagulation variables; the maximum median ratio for aPTT (in relationship to the value before the first dalteparin injection) was 1.23. CONCLUSIONS AND CLINICAL RELEVANCE Results of this study indicated that this treatment protocol resulted in reproducible anti-Xa activity in cats that was mostly within the targeted peak range of anti-Xa activity recommended for humans. Treatment in accordance with this protocol may not require routine coagulation monitoring of cats, but this must be confirmed in feline patients.

Blocking inhibition of prothrombinase by tissue factor pathway inhibitor alpha: a procoagulant property of heparins.

Unfractionated heparin (UFH) has procoagulant activity in antithrombin/heparin cofactor II (HCII)-depleted plasma. UFH prevents tissue factor pathway inhibitor alpha (TFPIα) from inhibiting the procoagulant enzyme complex, prothrombinase, providing a possible mechanism for its procoagulant activity. The procoagulant potential of UFH and various low molecular weight heparins (LMWHs) were characterized for TFPIα dependence, using thrombin generation assays performed with antithrombin/HCII-depleted plasma. UFH, the LMWHs enoxaparin and dalteparin, and the low anticoagulant LMWH 2-O, 3-O desulphated heparin (ODSH) all promoted thrombin generation, but fondaparinux did not, and this activity was blocked by a TFPIα antibody. UFH, enoxaparin, and dalteparin were anticoagulant in reactions containing 1-2% normal plasma. In prothrombinase activity assays, UFH, enoxaparin, dalteparin and ODSH blocked prothrombinase inhibition by TFPIα, while again fondaparinux did not. In both the plasma and purified assays, LMWHs displayed greater procoagulant potential than UFH, even when normalized to saccharide concentration. These biochemical data reveal that UFH and LMWHs, but not fondaparinux, block prothrombinase inhibition by TFPIα, thereby producing their paradoxical procoagulant activity observed in the absence of antithrombin/HCII. The findings may help to understand the complex pathophysiology and treatment of patients that are simultaneously bleeding and clotting, such as those with disseminated intravascular coagulation.

Formation of an Antral Follicle-Like Structure by Bovine Cumulus-Oocyte Complexes Embedded with Fragmin/Protamine Microparticles.

Fragmin/protamine microparticles (F/P MPs) approximately 0.5-1 µM in diameter were prepared by the simple mixing of fragmin with protamine. This study investigated the effects of F/P MP-containing collagen gels as a hormone carrier on the formation of antral follicle-like structures and on the development of growing bovine oocytes. The supplementation of F/P MPs in collagen gels contributed to the beneficial effects of follicle stimulating hormone (FSH) on the formation and size of antral follicle-like structures. The F/P MPs may serve as potential hormone carriers for the growth of cultured bovine oocytes from early antral follicles.

A retrospective analysis of outcomes of dalteparin use in pediatric patients: a single institution experience.

BACKGROUND: Dalteparin is a commonly used low molecular weight heparin (LMWH) with extensive safety data in adults. With distinct advantages of once daily dosing and relative safety in renal impairment, it has been used off-label in pediatric practice; however, age-based dosing guidelines, safety and efficacy data in children are evolving. OBJECTIVES: To report our institutional experience with the use of dalteparin in the treatment and prophylaxis of venous thromboembolism (VTE) in pediatric patients. PATIENTS/METHODS: Retrospective chart review of all children (0-18years) that received dalteparin from December 1, 2000 through December 31, 2011. Doses per unit body weight per day (units/kg/day) were calculated for age-based group comparisons. RESULTS: Of 166 patients identified, 116 (70%) received prophylactic doses while 50 (30%) received therapeutic doses of dalteparin. Infants (<1year) required significantly higher weight-based dosing to achieve therapeutic anti-Xa levels compared to children (1-10years) or adolescents (>10-18years) (mean dose units/kg/day; 396.6 versus 236.7 and 178.8 respectively, p<0.0001). Overall response rate, including complete and partial thrombus resolution, was 83%. Bleeding complications were minor and the rates were similar in therapeutic and prophylaxis patients. No significant differences in dosing or bleeding events were noted based on obesity or malignancy. CONCLUSIONS: In our experience, dalteparin is effective for prophylaxis and therapy of VTE in pediatric patients. Dosing should be customized in an age-based manner with close monitoring of anti-Xa activity in order to achieve optimal levels, prevent bleeding complications, and to allow full benefit of prevention or therapy of thrombotic complications.

The role of hepcidin in chronic mild stress-induced depression.

Depression is one of the most prevalent challenges of mental conditions. Yet its exact etiology has not been clear. Chronic stress increases the production of cytokines, which can lead to depression. Hepcidin, an iron modulator, is involved in the inflammation process as well as iron homeostasis. This study was designed to investigate the role of hepcidin, on stress-induced depression. 60 male wistar rats were entered the experiment. We used a chronic unpredictable mild stress (for 28 days) as a rat model of depression. In stressed group, three subgroups were treated with three different doses of dalteparin (a hepcidin inhibitor): 70IU/kg, 100IU/kg and 140IU/kg daily, for 4 weeks. The animals in the stressed group had more depressive-like behavior than the control group. Moreover, chronic mild stress produced an increased serum interleukin-6 levels. These effects were accompanied by an obvious increase in hepcidin mRNA level and iron content in the hippocampus. These changes were blocked by the injection of dalteparin. In conclusion, inhibition of hepcidin may reduce many pathological changes seen in stress-induced depressive disorders.

Platelet-rich plasma-containing fragmin-protamine micro-nanoparticles promote epithelialization and angiogenesis in split-thickness skin graft donor sites.

BACKGROUND: Platelet-rich plasma (PRP) contains multiple growth factors, and fragmin-protamine micro-nanoparticles (F-P M-NPs) significantly enhance and stabilize growth factors. The purpose of this study was to evaluate the effects of PRP-containing F-P M-NPs (PRP&F-P M-NPs) on wound repair in split-thickness skin graft (STSG-) donor sites (DS). MATERIALS AND METHODS: A total of 56 inbred male rats were anesthetized and split-thickness skin graft donor site (STSG-DS) were created with a Padgett dermatome. PRP&F-P M-NPs, F-P M-NPs, PRP, and saline (control) were then intradermally injected evenly into the STSG-DSs. On 3, 4, 5, 7, and 10 d after creation of STSG-DS, skin sample sections were stained with hematoxylin and eosin to evaluate reepithelialization and angiogenesis. RESULTS: Treatment of STSG-DS with PRP&F-P M-NPs effectively promoted epithelialization and new vessel formation compared with those treated with PRP, F-P M-NPs, and control (saline). CONCLUSIONS: The intradermal injection of PRP&F-P M-NPs promotes epithelialization and angiogenesis in STSG-DS wounds.

Effect of dalteparin on atherosclerotic lesion formation in apolipoprotein E-deficient mice.

We aimed to investigate whether prolonged treatment with dalteparin could inhibit plaque progression. With C57BL/6J mice as the control, genetically deficient apolipoprotein E (apo E) male mice of C57BL/6J strain (apo E(-/-)) were randomly divided into 3 groups. The model group received no dalteparin, while the other 2 groups received dalteparin at 100 and 200 U/kg d, respectively. The aorta was harvested for hematoxylin and eosin staining to observe plaque formation and for immunohistochemical staining to detect the expression of oxidized low-density lipoprotein receptor 1 (LOX-1). The expression of LOX-1 messenger RNA was detected by reverse transcription polymerase chain reaction, while the expression of LOX-1 protein was detected by Western blotting. Dalteparin decreased aortic plaque volume and inhibited aortic LOX-1 protein expression in apo E(-/-) mice. The effect persisted 4 weeks after dalteparin treatment was discontinued. Dalteparin may inhibit atherosclerotic lesions by downregulating the expression of LOX-1 protein.

Hypoxia and the anticoagulants dalteparin and acetylsalicylic acid affect human placental amino acid transport.

BACKGROUND: Anticoagulants, e.g. low-molecular weight heparins (LMWHs) and acetylsalicylic acid (ASA) are prescribed to women at risk for pregnancy complications that are associated with impaired placentation and placental hypoxia. Beyond their role as anticoagulants these compounds exhibit direct effects on trophoblast but their impact on placental function is unknown. The amino acid transport systems A and L, which preferably transfer essential amino acids, are well-described models to study placental nutrient transport. We aimed to examine the effect of hypoxia, LMWHs and ASA on the activity of the placental amino acid transport systems A and L and associated signalling mechanisms. METHODS: The uptake of C14-MeAIB (system A) or H3-leucin (system L) was investigated after incubation of primary villous fragments isolated from term placentas. Villous tissue was incubated at 2% O2 (hypoxia), 8% O2 and standard culture conditions (21% O2) or at 2% O2 and 21% O2 with dalteparin or ASA. Activation of the JAK/STAT or mTOR signalling pathways was determined by Western analysis of total and phosphorylated STAT3 or Raptor. RESULTS: Hypoxia decreased system A mediated MeAIB uptake and increased system L mediated leucine uptake compared to standard culture conditions (21% O2). This was accompanied by an impairment of STAT3 and a stimulation of Raptor signalling. System L activity increased at 8% O2. Dalteparin treatment reduced system A and system L activity under normoxic conditions and ASA (1 mM) decreased system A and L transporter activity under normoxic and hypoxic conditions. CONCLUSIONS: Our data underline the dependency of placental function on oxygen supply. LMWHs and ASA are not able to reverse the effects of hypoxia on placental amino acid transport. These findings and the uncovering of the signalling mechanisms in more detail will help to understand the impact of LMWHs and ASA on placental function and fetal growth.