Acquired Hemophilia A with a Rare Presentation of Acute Subdural Hematoma.

An 80-year-old man was admitted for acute subdural hematoma caused by a mild brain injury. His coagulation test showed an isolated prolongation of activated partial thromboplastin time (aPTT). Though the subdural hematoma did not progress, oozing bleed from the wound of tracheostomy continued. Failure of correction on aPTT mixing test supported the presence of an inhibitor to a coagulation factor. Once the diagnosis of acquired hemophilia A (AHA) was made, steroid therapy was performed, which leads him to complete remission of AHA. Isolated prolongation of aPTT can be the key to diagnose a rare coagulopathy, such as AHA.

Post-marketing surveillance data of thrombomodulin alfa: sub-analysis in patients with sepsis-induced disseminated intravascular coagulation.

BACKGROUND: Thrombomodulin alfa (TM-α, recombinant thrombomodulin) significantly improved disseminated intravascular coagulation (DIC) when compared with heparin therapy in a phase III study. Post-marketing surveillance of TM-α was performed to evaluate the effects and safety in patients with sepsis-induced DIC. METHODS: From May 2008 to April 2010, a total of 1,787 patients with sepsis-induced DIC treated with TM-α were registered. DIC was diagnosed based on the Japanese Association for Acute Medicine (JAAM) criteria. The DIC resolution and survival rates on day 28 after the last TM-α administration, and changes in DIC, systemic inflammatory response syndrome (SIRS), and sequential organ failure assessment (SOFA) scores and coagulation and inflammation markers were evaluated. RESULTS: The most frequent underlying disease was infectious focus-unknown sepsis (29.8%). The mean ± SD values of age, dose, and the duration of TM-α administration were 64.7 ± 20.3 years, 297.3 ± 111.4 U/kg/day, and 5.6 ± 3.4 days, respectively. A total of 1,320 subjects (73.9%) received combined administration with other anticoagulants. Both coagulation and inflammation markers, such as fibrin/fibrinogen degradation products, prothrombin time ratio, thrombin-antithrombin complex, and C-reactive protein, as well as JAAM DIC, SIRS, and SOFA scores, significantly and simultaneously decreased after TM-α administration (p < 0.001). DIC resolution and 28-day survival rates were 44.4% and 66.0%, respectively. The 28-day survival rate decreased significantly according to the duration of DIC before TM-α administration (p < 0.001). Total adverse drug reactions (ADRs), bleeding ADRs, and serious bleeding adverse events occurred in 126 (7.1%), 98 (5.5%), and 121 (6.8%) subjects, respectively. On day 28, after the last TM-α administration available for an antibody test, only one patient was positive for anti-TM-α antibodies (0.11%). CONCLUSION: Our results suggest that TM-α is most effective for treating patients with sepsis-induced DIC when administered within the first 3 days after diagnosis.

Living donor liver transplantation from an asymptomatic donor with mild coagulation factor IX deficiency: report of a case.

The use of donors with coagulation FIX deficiency is controversial, and there are no current protocols for peri-transplant management. We herein describe the first reported case of a pediatric LDLT from an asymptomatic donor with mild coagulation FIX deficiency. A 32-yr-old female was evaluated as a donor for her 12-month-old daughter with biliary atresia. The donor's pretransplant coagulation tests revealed asymptomatic mild coagulation FIX deficiency (FIX activity 60.8%). Freeze-dried human blood coagulation FIX concentrate was administered before the dissection of the liver and 12 h afterwards by bolus infusion (40 U/kg) and was continued on POD 1. The bleeding volume at LDLT was 590 mL. On POD 1, 3, 5, and 13, the coagulation FIX activity of the donor was 121.3%, 130.6%, 114.6%, and 50.2%, respectively. The donor's post-transplant course was uneventful, and the recipient is currently doing well at 18 months after LDLT. The FIX activity of the donor and recipient at nine months after LDLT was 39.2% and 58.0%, respectively. LDLT from donors with mild coagulation FIX deficiency could be performed effectively and safely using peri-transplant short-term coagulation FIX replacement and long-term monitoring of the plasma FIX level in the donor.

Thrombomodulin alfa treatment in patients with acute promyelocytic leukemia and disseminated intravascular coagulation: a retrospective analysis of an open-label, multicenter, post-marketing surveillance study cohort.

INTRODUCTION: Patients with acute promyelocytic leukemia (APL) can develop disseminated intravascular coagulation (DIC) that results in life-threatening hemorrhagic complications. Studies regarding the safety and efficacy of thrombomodulin alfa (TM-α; recombinant human soluble thrombomodulin) in patients with APL and DIC are limited. MATERIALS AND METHODS: A retrospective evaluation was performed on a cohort of 172 patients with APL from an open-label, multicenter, post-marketing surveillance study of TM-α. RESULTS: Of the 172 patients, 31 were relapse/refractory APL patients, and 141 were newly diagnosed APL patients. Within the first 30 days, 24 patients (14.0%) died, and six of those deaths (3.5%) were due to hemorrhage. In total, 12 patients (7.0%) had severe hemorrhagic complications. Both the early death rate due to hemorrhage as well as the severe hemorrhage rate did not exceed those in some recent population-based studies of patients with APL. Forty-nine patients received TM-α prior to the initiation of antileukemic treatment, and one patient experienced hemorrhagic early death (ED), suggesting that early TM-α treatment appeared to result in a reduction in the hemorrhagic ED rate. Moreover, TM-α improved coagulopathy regardless of concomitant all-trans retinoic acid treatment. CONCLUSIONS: This study confirmed the safety and efficacy of TM-α in daily clinical practice for patients with APL and DIC. TM-α appeared to reduce hemorrhagic early deaths due to DIC in patients with APL who were receiving antileukemic treatment.

Postmarketing Surveillance of Recombinant Human Soluble Thrombomodulin (Thrombomodulin α) in Pediatric Patients With Disseminated Intravascular Coagulation.

Recombinant human soluble thrombomodulin (thrombomodulin α [TM-α]) has been marketed as a novel anticoagulant for disseminated intravascular coagulation (DIC) in Japan since 2008. Postmarketing surveillance (PMS) has been conducted since its approval. As effectiveness and safety were not previously determined in pediatric patients, this study evaluated PMS data and examined the usefulness of TM-α in treating pediatric DIC. After excluding newborn infants, data for 210 pediatric patients were analyzed and compared to 3786 adult patients. The day after the last TM-α administration, DIC had resolved in 58.5% of the patients. At 28 days after the last TM-α administration, the survival rate was 71.6%. Nineteen episodes of adverse drug reactions were observed in 11 patients but no significant differences were noted for effectiveness and safety. Although this study was limited by its retrospective design, including selection biases and no limitation on concomitant use of other anticoagulants, TM-α appears to be useful for the treatment of DIC in both pediatric and adult patients.

Combination of thrombin-antithrombin complex, plasminogen activator inhibitor-1, and protein C activity for early identification of severe coagulopathy in initial phase of sepsis: a prospective observational study.

INTRODUCTION: Current criteria for early diagnosis of coagulopathy in sepsis are limited. We postulated that coagulopathy is already complicated with sepsis in the initial phase, and severe coagulopathy or disseminated intravascular coagulation (DIC) becomes overt after progressive consumption of platelet and coagulation factors. To determine early diagnostic markers for severe coagulopathy, we evaluated plasma biomarkers for association with subsequent development of overt DIC in patients with sepsis. METHODS: A single-center, prospective observational study was conducted in an adult ICU at a university hospital. Plasma samples were obtained from patients with sepsis at ICU admission. Fourteen biomarkers including global markers (platelet count, prothrombin time, activated partial thromboplastin time, fibrinogen and fibrin degradation product (FDP)); markers of thrombin generation (thrombin-antithrombin complex (TAT) and soluble fibrin); markers of anticoagulants (protein C (PC) and antithrombin); markers of fibrinolysis (plasminogen, α2-plasmin inhibitor (PI), plasmin-α2-PI complex, and plasminogen activator inhibitor (PAI)-1); and a marker of endothelial activation (soluble E-selectin) were assayed. Patients who had overt DIC at baseline were excluded, and the remaining patients were followed for development of overt DIC in 5 days, and for mortality in 28 days. RESULTS: A total of 77 patients were enrolled, and 37 developed overt DIC within the following 5 days. Most patients demonstrated hemostatic abnormalities at baseline with 98.7% TAT, 97.4% FDP and 88.3% PC. Most hemostatic biomarkers at baseline were significantly associated with subsequent development of overt DIC. Notably, TAT, PAI-1 and PC discriminated well between patients with and without developing overt DIC (area under the receiver operating characteristic curve (AUROC), 0.77 (95% confidence interval, 0.64 to 0.86); 0.87 (0.78 to 0.92); 0.85 (0.76 to 0.91), respectively), and using the three together, significantly improved the AUROC up to 0.95 (vs. TAT, PAI-1, and PC). Among the significant diagnostic markers for overt DIC, TAT and PAI-1 were also good predictors of 28-day mortality (AUROC, 0.77 and 0.81, respectively). CONCLUSIONS: Severe coagulation and fibrinolytic abnormalities on ICU admission were associated with subsequent development of overt DIC. A single measurement of TAT, PAI-1, and PC activity could identify patients with ongoing severe coagulopathy, early in the course of sepsis.

Paxillin is an intrinsic negative regulator of platelet activation in mice.

BACKGROUND: Paxillin is a LIM domain protein localized at integrin-mediated focal adhesions. Although paxillin is thought to modulate the functions of integrins, little is known about the contribution of paxillin to signaling pathways in platelets. Here, we studied the role of paxillin in platelet activation in vitro and in vivo. METHODS AND RESULTS: We generated paxillin knockdown (Pxn-KD) platelets in mice by transplanting bone marrow cells transduced with a lentiviral vector carrying a short hairpin RNA sequence, and confirmed that paxillin expression was significantly reduced in platelets derived from the transduced cells. Pxn-KD platelets showed a slight increased in size and augmented integrin αIIbß3 activation following stimulation of multiple receptors including glycoprotein VI and G protein-coupled receptors. Thromboxane A2 biosynthesis and the release of α-granules and dense granules in response to agonist stimulation were also enhanced in Pxn-KD platelets. However, Pxn-KD did not increase tyrosine phosphorylation or intracellular calcium mobilization. Intravital imaging confirmed that Pxn-KD enhanced thrombus formation in vivo. CONCLUSIONS: Our findings suggest that paxillin negatively regulates several common platelet signaling pathways, resulting in the activation of integrin αIIbß3 and release reactions.

Post-marketing surveillance of thrombomodulin alfa, a novel treatment of disseminated intravascular coagulation - safety and efficacy in 1,032 patients with hematologic malignancy.

INTRODUCTION: Post-marketing surveillance of thrombomodulin alfa (TM-α) was performed to evaluate safety and efficacy in patients with disseminated intravascular coagulation (DIC) with hematologic malignancy. MATERIALS AND METHODS: All patients treated with TM-α from May 2008 to April 2010 in Japan were included. Information about baseline characteristics, safety, and efficacy were collected. The DIC resolution rate, survival rate on Day 28 after the last TM-α administration, and changes in DIC score and coagulation tests were evaluated. RESULTS: The underlying diseases associated with DIC were acute myeloid leukemia (except for acute promyelocytic leukemia, n=350), lymphoma (n=199), acute promyelocytic leukemia (n=172), acute lymphoblastic leukemia (n=156), myelodysplastic syndromes (n=61), and other (n=94). The incidence rates of bleeding-related adverse events and adverse drug reactions were 17.8% and 4.6%, respectively. In subjects with bleeding symptoms at baseline, 55.0% were assessed as disappeared or improved based on symptoms after TM-α treatment. The DIC resolution and survival rates were 55.9% and 70.7%, respectively. The DIC score and coagulation tests including thrombin-antithrombin complex (TAT) were significantly improved. Coagulation tests were significantly improved after TM-α treatment even in subjects whose clinical course of underlying disease was assessed as unchanged or exacerbated. CONCLUSIONS: This surveillance confirmed the safety and efficacy of TM-α in clinical practice, thus TM-α may be an ideal treatment for patients with DIC based upon hematologic malignancy.

The prevalence of neutralizing antibodies against adeno-associated virus capsids is reduced in young Japanese individuals.

Pre-existing antibodies against adeno-associated virus (AAV), caused by natural AAV infections, interfere with recombinant AAV vector-mediated gene transfer. We studied the prevalence of neutralizing antibodies against AAV serotypes 1, 2, 5, 8, and 9 in healthy subjects (n = 85) and hemophilia patients (n = 59) in a Japanese population. For healthy subjects, the prevalence of neutralizing antibodies against AAV serotypes 1, 2, 5, 8, and 9 was 36.5%, 35.3%, 37.6%, 32.9%, and 36.5%, respectively, while that in hemophilia patients was 39.7%, 28.8%, 35.6%, 32.9%, and 27.4%, respectively. There was no difference in the prevalence of neutralizing antibody against each AAV serotype between the healthy subjects and the hemophilia patients. The prevalence of neutralizing antibodies against all AAV serotypes increased with age in both healthy subjects and hemophilia patients. High titers of neutralizing antibodies against AAV2 (≥1:224) and AAV8 (≥1:224) were more evident in older individuals (≥42 years old). Approximately 50% of all screened individuals were seronegative for neutralizing antibodies against each AAV tested, while approximately 25% of individuals were seropositive for each AAV serotype tested. The prevalence of seronegativity for all AAV serotypes was 67.0% (healthy subjects, 68.6%; hemophilia patients, 65.0%) and 18.6% (healthy subjects, 20.5%; hemophilia patients, 15.7%) in young (<42 years old) and older subjects (≥42 years old), respectively. The findings from this study suggested that young subjects are more likely to be eligible for gene therapy based on AAV vectors delivered via an intravascular route because of the low prevalence of antibodies to AAV capsids.

Recombinant soluble human thrombomodulin (thrombomodulin alfa) in the treatment of neonatal disseminated intravascular coagulation.

UNLABELLED: Recombinant soluble human thrombomodulin (TM-α) has been shown to be useful in the treatment of disseminated intravascular coagulation (DIC) in a heparin-controlled study and has been available for clinical use in Japan since 2008. However, data on its use for neonatal DIC have not been reported from any clinical studies, so efficacy and safety were analyzed in 60 neonatal DIC patients identified in post-marketing surveillance. The DIC resolution rate as of the day after last administration of TM-α was 47.1 %, and the survival rate at 28 days after last administration was 76.7 %. Hemostatic test result profiles revealed decreased levels of fibrin/fibrinogen degradation products and increased platelet counts and antithrombin activity. Incidences of adverse drug reactions, bleeding-related adverse drug reactions, and bleeding-related adverse events were 6.7, 6.7, and 16.7 %, respectively, with no significant differences between neonatal, pediatric (excluding neonates), and adult DIC patients. CONCLUSION: This surveillance provided real-world data on the safety and effectiveness of TM-alpha in the treatment of neonatal DIC in general practice settings.

Distinct reactivity of the commercially available monoclonal antibodies of D-dimer and plasma FDP testing to the molecular variants of fibrin degradation products.

Fibrin degradation products (FDP) are an important marker of coagulopathy. We assessed the reactivity of the monoclonal antibodies used in clinical laboratory testing (6 D-dimer reagents, D-dimer-1-6; 4 plasma FDP reagents, plasma FDP-1-4) to quantify FDP using in vitro-generated FDP as well as FDP in clinical samples. The monoclonal antibodies used in D-dimer-1, -2, -5, and -6 reacted poorly to the low molecular weight forms of in vitro-generated FDP. The monoclonal antibodies used in D-dimer-3 and -4 had better reactivity to the low molecular weight forms of in vitro-generated FDP. The monoclonal antibodies used in plasma FDP-2, -3, and -4 reacted well to the high and low molecular weight FDP forms, while the monoclonal antibody in plasma FDP-1 reacted poorly to the low molecular weight FDP forms. Analysis of clinical samples revealed deviations in FDP molecular weight forms in DIC samples. The reactivity of the monoclonal antibodies of laboratory FDP testing to FDP variants in clinical samples was similar to that of in vitro-generated FDP. In conclusion, the monoclonal antibodies used in clinical laboratories to detect FDP have distinct reactivity to the molecular variants of FDP generated in vitro as well as those present in clinical samples. Our findings support the consensus for the standardization of D-dimer and plasma FDP testing.

Acquired factor V inhibitor associated with life-threatening bleeding and a mixing test result that indicated coagulation factor deficiency.

A mixing test is useful for distinguishing between coagulation factor deficiency and the presence of inhibitor as the cause of coagulopathy. However, we experienced a patient with acquired factor V (FV) inhibitor whose mixing test showed a coagulation factor deficiency pattern. A 65-year-old man with a tendency for bleeding was referred to our center. The laboratory data showed remarkable prolongation of prothrombin time and activated partial thromboplastin time (APTT). FV activity was less than 3%. A mixing test showed a coagulation factor deficiency pattern. However, neither the tendency for bleeding nor the coagulation tests were corrected by transfusion of fresh frozen plasma. A few days later, a positive test for FV inhibitor of 3 Bethesda units was obtained. Therefore, we started prednisolone and plasma exchange, and the coagulation test results normalized after 6 weeks. Although an incubation period is generally not considered necessary in a mixing test for FV inhibitor, we repeated mixing tests with various incubation periods and confirmed an incubation period-dependent prolongation of the APTT. Therefore, a mixing test with an incubation period is recommended for the detection of FV inhibitor, since a mixing test without an incubation period may show a coagulation factor deficiency pattern when the titer of FV inhibitor is low.

Overexpression of factor VII ameliorates bleeding diathesis of factor VIII-deficient mice with inhibitors.

INTRODUCTION: Factor VIII (FVIII) treatment for hemophilia A has difficulties in correcting bleeding diathesis in the presence of inhibitors. MATERIALS AND METHODS: An adeno-associated virus type 8 (AAV8) vector containing the factor VII (FVII) gene or the activated factor VII (FVIIa) gene was used to investigate the therapeutic effect of FVII or FVIIa overexpression in FVIII-deficient mice with inhibitors. RESULTS: Following repeated human FVIII injection, FVIII-deficient mice developed anti-human FVIII antibodies that cross-reacted with mouse FVIII. High transgene expression of murine FVII or murine FVIIa was achieved using the AAV8 vector and resulted in increased blood FVII activity greater than 800% of normal murine FVII levels in vector-injected FVIII-deficient mice. Thromboelastography analysis showed significant improvements in clotting time, clot formation time, α angle, and mean clot firmness in AAV8 vector-injected FVIII-deficient mice with inhibitors. Overexpression of FVIIa ameliorated the bleeding phenotype of FVIII-deficient mice with inhibitors and significantly increased the survival rate after tail clipping. In addition, overexpression of FVII increased the survival rate of FVIII-deficient mice with inhibitors after tail clipping though it was not as efficient as FVIIa overexpression. CONCLUSIONS: These data suggest that FVII overexpression is an alternative strategy for the treatment of hemophilia A with inhibitors.

Impact of recombinant soluble thrombomodulin (thrombomodulin alfa) on disseminated intravascular coagulation.

INTRODUCTION: We assessed the safety and effectiveness of recombinant soluble thrombomodulin (thrombomodulin alfa, TM-α) in the treatment of disseminated intravascular coagulation (DIC) in a post-marketing surveillance. METHODS: The cases of 3548 patients with DIC caused by infection (n=2516, Infection-DIC) or hematological malignancy (n=1032, Hemat-DIC) were analyzed and compared to the results of a phase III (P-III) study. RESULTS: The DIC scores were significantly decreased in the Infection-DIC and Hemat-DIC groups with TM-α treatment (both P<0.001). The incidences of critical bleeding adverse drug reactions (ADRs) in the Infection-DIC and Hemat-DIC groups were 2.6% and 2.4%, and the survival rates were 64.1% and 70.7%, respectively. Patients with DIC were subcategorized into three groups (Infection-DIC-1 or Hemat-DIC-1, P-III criteria-matched patients; Infection-DIC-2 or Hemat-DIC-2, P-III criteria-non-matched patients treated solely with TM-α; and Infection-DIC-3 or Hemat-DIC-3, P-III criteria-non-matched patients treated with TM-α and other concomitant anticoagulants). Subcategory analysis revealed that the incidences of critical bleeding ADRs of Hemat-DIC-2 and Hemat-DIC-3 were significantly higher and their survival rates were significantly lower than those of Hemat-DIC-1. By multivariate analysis in Hemat-DIC, younger age (odds ratio: 2.629, P=0.0033) and pre-existing bleeding (odds ratio: 2.044, P=0.019) were found to affect bleeding ADRs and the severity of underlying disease was the most important factor for survival rate (odds ratio: 0.288, P<0.001). CONCLUSIONS: This surveillance provided real-world data for the safety and effectiveness of TM-α in the treatment of Infection-DIC and Hemat-DIC in general practice settings.

Evaluation of hemostatic biomarker abnormalities that precede platelet count decline in critically ill patients with sepsis.

PURPOSE: The hemostatic biomarkers for early diagnosis of sepsis-associated coagulopathy have not been identified. The purpose of this study was to evaluate hemostatic biomarker abnormalities preceding a decrease in platelet count, which is a surrogate indicator of overt coagulopathy in sepsis. MATERIALS AND METHODS: Seventy-five septic patients with a platelet count more than 80×10(3)/µL were retrospectively analyzed. Hemostatic biomarkers at intensive care unit admission were compared between patients with and patients without a subsequent decrease in platelet count (≥30% within 5 days), and the ability of biomarkers to predict a decrease in platelet count was evaluated. RESULTS: Forty-two patients (56.0%) developed a subsequent decrease in platelet count. Severity of illness, incidence of organ dysfunction, and 28-day mortality rate were higher in patients with a subsequent decrease in platelet count. There were significant differences between patients with and patients without a subsequent decrease in platelet count in prothrombin time-international normalized ratio, fibrinogen, thrombin-antithrombin complex, antithrombin, protein C (PC), plasminogen, and α2-plasmin inhibitor (α2-PI). Receiver operating characteristic curve analysis showed that PC (area under the curve, 0.869; 95% confidence interval, 0.699-0.951) and α2-PI (area under the curve, 0.885; 95% confidence interval, 0.714-0.959) were strong predictors of a subsequent decrease in platelet count. CONCLUSIONS: Decreased PC and α2-PI activity preceded a decrease in platelet count in intensive care unit patients with sepsis.

Tissue plasminogen activator deficiency promotes early phase regeneration in the olfactory epithelium after bulbectomy.

BACKGROUND: Tissue type plasminogen activator (tPA) functions as a fibrinolytic factor in the blood and has unique roles in the nervous system. However, the role of tPA in the olfactory epithelium (OE) is still unclear. Generally, surgical ablation of the olfactory bulb (bulbectomy) triggers degeneration followed by regeneration of OE. In this experimental study, we investigated the role of tPA in OE regeneration. METHODS: Wild-type (WT) mice and tPA-knockout (tPA(-/-) ) mice were subjected to bulbectomy. Reverse-transcription polymerase chain reaction (RT-PCR), in situ hybridization, and immunohistochemical examination was done to detect tPA expression in the olfactory bulb and OE. Cellular proliferation and apoptosis was also monitored in the OE. RESULTS: Before bulbectomy, tPA was found to be expressed in the olfactory bulb and OE. OE degenerated to a similar extent in both strains between 0 and 3 days after bulbectomy. However, OE was thicker and contained more cells in tPA(-/-) mice than in WT mice at 7 days after bulbectomy. Moreover, the number of apoptotic bodies was reduced and the number of proliferating cells was increased in the OE of tPA(-/-) mice compared to WT mice, after bulbectomy. Transmission electron microscopy revealed continuous degeneration of the OE for up to 7 days after bulbectomy in WT mice. In contrast, we observed some intact olfactory vesicles and almost normal supporting cells in the OE of tPA(-/-) mice, at 7 days after bulbectomy. CONCLUSION: The current findings show that the tPA-plasmin system plays an inhibitory role in the regulation of regeneration in the OE.

Minimizing the inhibitory effect of neutralizing antibody for efficient gene expression in the liver with adeno-associated virus 8 vectors.

Neutralizing antibodies (NAbs) against adeno-associated viruses (AAVs) are known to interfere with AAV vector-mediated gene transfer by intravascular delivery. Evading the inhibitory effects of antibodies against AAV vectors is necessary for efficient transfer of therapeutic genes clinically. For this purpose, we tested the efficacy of saline flushing in order to avoid contact of vectors with NAbs present in blood. Direct injection of the AAV8 vector carrying the factor IX (FIX) gene into the portal vein of macaques using saline flushing achieved transgene-derived FIX expression (4.7 ± 2.10-10.1 ± 5.45% of normal human FIX concentration) in the presence of NAbs. Expression was as efficient as that (5.43 ± 2.59-12.68 ± 4.83%) in macaques lacking NAbs. We next tested the efficacy of saline flushing using less invasive balloon catheter-guided injection. This approach also resulted in efficient expression of transgene-derived FIX (2.5 ± 1.06-9.0 ± 2.37%) in the presence of NAbs (14-56× dilutions). NAbs at this range of titers reduced the efficiency of transduction in the macaque liver by 100-fold when the same vector was injected into mesenteric veins without balloon catheters. Our results suggest that portal vein-directed vector delivery strategies with flushing to remove blood are efficacious for minimizing the inhibitory effect of anti-AAV antibodies.

Porcine model of hemophilia A.

Hemophilia A is a common X chromosome-linked genetic bleeding disorder caused by abnormalities in the coagulation factor VIII gene (F8). Hemophilia A patients suffer from a bleeding diathesis, such as life-threatening bleeding in the brain and harmful bleeding in joints and muscles. Because it could potentially be cured by gene therapy, subhuman animal models have been sought. Current mouse hemophilia A models generated by gene targeting of the F8 have difficulties to extrapolate human disease due to differences in the coagulation and immune systems between mice and humans. Here, we generated a porcine model of hemophilia A by nuclear transfer cloning from F8-targeted fibroblasts. The hemophilia A pigs showed a severe bleeding tendency upon birth, similar to human severe hemophiliacs, but in contrast to hemophilia A mice which rarely bleed under standard breed conditions. Infusion of human factor VIII was effective in stopping bleeding and reducing the bleeding frequency of a hemophilia A piglet but was blocked by the inhibitor against human factor VIII. These data suggest that the hemophilia A pig is a severe hemophilia A animal model for studying not only hemophilia A gene therapy but also the next generation recombinant coagulation factors, such as recombinant factor VIII variants with a slower clearance rate.

Il2rg gene-targeted severe combined immunodeficiency pigs.

A porcine model of severe combined immunodeficiency (SCID) promises to facilitate human cancer studies, the humanization of tissue for xenotransplantation, and the evaluation of stem cells for clinical therapy, but SCID pigs have not been described. We report here the generation and preliminary evaluation of a porcine SCID model. Fibroblasts containing a targeted disruption of the X-linked interleukin-2 receptor gamma chain gene, Il2rg, were used as donors to generate cloned pigs by serial nuclear transfer. Germline transmission of the Il2rg deletion produced healthy Il2rg(+/-) females, while Il2rg(-/Y) males were athymic and exhibited markedly impaired immunoglobulin and T and NK cell production, robustly recapitulating human SCID. Following allogeneic bone marrow transplantation, donor cells stably integrated in Il2rg(-/Y) heterozygotes and reconstituted the Il2rg(-/Y) lymphoid lineage. The SCID pigs described here represent a step toward the comprehensive evaluation of preclinical cellular regenerative strategies.

FTY720 improves functional recovery after spinal cord injury by primarily nonimmunomodulatory mechanisms.

Spinal cord injury (SCI) is an incapacitating injury that can result in limited functional recovery. We have previously shown increases in the lysophospholipid mediator, sphingosine-1-phosphate (S1P), in the spinal cord after contusion injury. To apply S1P receptor modulation to the treatment of SCI, we examined the therapeutic effects of FTY720, an S1P receptor agonist, on locomotor recovery after SCI in mice. Oral administration of FTY720 shortly after contusion SCI significantly improved motor function recovery, as assessed by both Basso Mouse Scale scores and Rotarod Performance test results. FTY720 induced lymphopenia and reduced T-cell infiltration in the spinal cord after SCI but did not affect the early infiltration of neutrophils and the activation of microglia. In addition, plasma levels and mRNA expression of inflammatory cytokines in the spinal cord after SCI were not attenuated by FTY720. Vascular permeability and astrocyte accumulation were both decreased by FTY720 in the injured spinal cord. The therapeutic effects of FTY720 were not solely dependent on immune modulation, as confirmed by the demonstration that FTY720 also ameliorated motor function after SCI in mice with severe combined immunodeficiency. Finally, the S1P(1) receptor agonist, SEW2871, partly mimicked the therapeutic effect of FTY720. Our data highlight the importance of immune-independent functions of FTY720 in decreasing vascular permeability and astrogliosis in the injured spinal cord and promoting locomotor function recovery after SCI.