Lipid nanoparticles and siRNA targeting plasminogen provide lasting inhibition of fibrinolysis in mouse and dog models of hemophilia A

Antifibrinolytic drugs are used extensively for on-demand treatment of severe acute bleeding. Controlling fibrinolysis may also be an effective strategy to prevent or lessen chronic recurring bleeding in bleeding disorders such as hemophilia A (HA), but current antifibrinolytics have unfavorable pharmacokinetic profiles. Here, we developed a long-lasting antifibrinolytic using small interfering RNA (siRNA) targeting plasminogen packaged in clinically used lipid nanoparticles (LNPs) and tested it to determine whether reducing plasmin activity in animal models of HA could decrease bleeding frequency and severity. Treatment with the siRNA-carrying LNPs reduced circulating plasminogen and suppressed fibrinolysis in wild-type and HA mice and dogs. In HA mice, hemostatic efficacy depended on the injury model; plasminogen knockdown improved hemostasis after a saphenous vein injury but not tail vein transection injury, suggesting that saphenous vein injury is a murine bleeding model sensitive to the contribution of fibrinolysis. In dogs with HA, LNPs carrying siRNA targeting plasminogen were as effective at stabilizing clots as tranexamic acid, a clinical antifibrinolytic, and in a pilot study of two dogs with HA, the incidence of spontaneous or excess bleeding was reduced during 4 months of prolonged knockdown. Collectively, these data demonstrate that long-acting antifibrinolytic therapy can be achieved and that it provides hemostatic benefit in animal models of HA.

Platelet-targeted gene therapy induces immune tolerance in hemophilia and beyond

Blood platelets have unique storage and delivery capabilities. Platelets play fundamental roles in hemostasis, inflammatory reactions, and immune responses. Beyond their functions, platelets have been used as a target for gene therapy. Platelet-targeted gene therapy aims to deliver a sustained expression of neo-protein in vivo by genetically modifying the target cells, resulting in a cure for the disease. Even though there has been substantial progress in the field of gene therapy, the potential development of immune responses to transgene products or vectors remains a significant concern. Of note, multiple preclinical studies using platelet-specific lentiviral gene delivery to hematopoietic stem cells in hemophilia have demonstrated promising results with therapeutic levels of neo-protein that rescue the hemorrhagic bleeding phenotype and induce antigen-specific immune tolerance. Further studies using ovalbumin as a surrogate protein for platelet gene therapy have shown robust antigen-specific immune tolerance induced via peripheral clonal deletions of antigen-specific CD4- and CD8-T effector cells and induction of antigen-specific regulatory T (Treg) cells. This review discusses platelet-targeted gene therapy, focusing on immune tolerance induction.

Pre-existing anti-factor VIII immunity alters therapeutic platelet-targeted factor VIII engraftment following busulfan conditioning through cytotoxic CD8 T cells

BACKGROUND

We previously demonstrated that busulfan preconditioning enabled sustained therapeutic platelet-derived factor VIII (FVIII) expression in naïve FVIII^null mice transplanted with 2bF8-transduced Sca-1⁺ cells. However, in mice with pre-existing inhibitors, platelet-FVIII expression was lost.

OBJECTIVE

In this study, we aimed to describe the mechanism of this platelet-FVIII loss.

METHODS

We monitored platelet-FVIII expression in FVIII^null mice that were immunized with rhFVIII to induce inhibitors and subsequently conditioned with busulfan before whole bone marrow transplantation or Sca-1⁺ hematopoietic stem cell transplantation (HSCT) from 2bF8 transgenic (2bF8^Tg) mice. Busulfan with or without antithymocyte globulin or anti-CD8 antibody was employed before 2bF8^Tg HSCT. Interferon gamma-ELISpot assay was used to assess which subset of cells was the target in platelet-FVIII loss. B-cell-deficient homozygous mutant mice were used to determine whether platelet-FVIII loss in FVIII-primed mice was mediated by antibody-dependent cellular cytotoxicity.

RESULTS

Platelet-FVIII expression was sustained in 2bF8^Tg bone marrow transplantation but not in 2bF8^Tg HSCT recipients. CD8 T-cell depletion in addition to busulfan preconditioning restored platelet-FVIII expression in 2bF8^Tg-HSCT recipients. ELISpot analyses showed that FVIII-primed CD8 T cells were efficiently restimulated by 2bF8^Tg-Sca-1⁺ cells and secreted interferon gamma, but were not stimulated by 2bF8^Tg platelets/megakaryocytes, suggesting that 2bF8^Tg-Sca-1⁺ cells are targets for FVIII-primed CD8 T cells. When 2bF8^Tg-Sca-1⁺ cells were transplanted into FVIII-primed homozygous mutant mice preconditioned with busulfan, no FVIII expression was detected, suggesting that antibody-dependent cellular cytotoxicity was not the mechanism of platelet-FVIII loss in FVIII-primed mice.

CONCLUSION

Pre-existng immunity can alter the engraftment of 2bF8^Tg-Sca-1⁺ cells through the cytotoxic CD8 T-cell-mediated pathway. Sufficient eradication of FVIII-primed CD8 T cells is critical for the success of platelet gene therapy in hemophilia A with inhibitors.

Targeting transmembrane-domain-less MOG expression to platelets prevents disease development in experimental autoimmune encephalomyelitis

Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease of the central nervous system with no cure yet. Here, we report genetic engineering of hematopoietic stem cells (HSCs) to express myelin oligodendrocyte glycoprotein (MOG), specifically in platelets, as a means of intervention to induce immune tolerance in experimental autoimmune encephalomyelitis (EAE), the mouse model of MS. The platelet-specific αIIb promoter was used to drive either a full-length or truncated MOG expression cassette. Platelet-MOG expression was introduced by lentivirus transduction of HSCs followed by transplantation. MOG protein was detected on the cell surface of platelets only in full-length MOG-transduced recipients, but MOG was detected in transmembrane-domain-less MOG_1-157-transduced platelets intracellularly. We found that targeting MOG expression to platelets could prevent EAE development and attenuate disease severity, including the loss of bladder control in transduced recipients. Elimination of the transmembrane domains of MOG significantly enhanced the clinical efficacy in preventing the onset and development of the disease and induced CD4⁺Foxp3⁺ Treg cells in the EAE model. Together, our data demonstrated that targeting transmembrane domain-deleted MOG expression to platelets is an effective strategy to induce immune tolerance in EAE, which could be a promising approach for the treatment of patients with MS autoimmune disease.

Thromboelastometry assessment of hemostatic properties in various murine models with coagulopathy and the effect of factor VIII therapeutics

BACKGROUND

Rotational thromboelastometry (ROTEM) has been commonly used to assess the viscoelastic properties of the blood clotting process in the clinic for patients with a hemostatic or prothrombotic disorder.

OBJECTIVE

To evaluate the capability of ROTEM in assessing hemostatic properties in whole blood from various mouse models with genetic bleeding or clotting disease and the effect of factor VIII (FVIII) therapeutics in FVIIInull mice.

METHODS

Mice with a genetic deficiency in either a coagulation factor or a platelet glycoprotein were used in this study. The properties of platelet- or plasma-FVIII were also assessed. Citrated blood from mice was recalcified and used for ROTEM analysis.

RESULTS

We found that blood collected from the vena cava could generate reliable results from ROTEM analysis, but not blood collected from the tail vein, retro-orbital plexus, or submandibular vein. Age and sex did not significantly affect the hemostatic properties determined by ROTEM analysis. Clotting time (CT) and clot formation time (CFT) were significantly prolonged in FVIIInull (5- and 9-fold, respectively) and FIXnull (4- and 5.7-fold, respectively) mice compared to wild-type (WT)-C57BL/6J mice. Platelet glycoprotein (GP)IIIanull mice had significantly prolonged CFT (8.4-fold) compared to WT-C57BL/6J mice. CT and CFT in factor V (FV) Leiden mice were significantly shortened with an increased α-angle compared to WT-C57BL/6J mice. Using ROTEM analysis, we showed that FVIII expressed in platelets or infused into whole blood restored hemostasis of FVIIInull mice in a dose-dependent manner.

CONCLUSION

ROTEM is a reliable and sensitive assay for assessing therapeutics on hemostatic properties in mouse models with a bleeding or clotting disorder.

Trichomoniasis and adverse birth outcomes: a systematic review and meta-analysis

BACKGROUND

Trichomoniasis commonly affects women of childbearing age and has been linked to several adverse birth outcomes.

OBJECTIVE

To elucidate the association between trichomoniasis in pregnant women and adverse birth outcomes, including preterm delivery, prelabour rupture of membranes and low birthweight.

SEARCH STRATEGY

MEDLINE, EMBASE and ClinicalTrials.gov were systematically searched in December 2020 without time or language restrictions.

SELECTION CRITERIA

Original research studies were included if they assessed at least one of the specified adverse birth outcomes in pregnant women with laboratory-diagnosed trichomoniasis.

DATA COLLECTION AND ANALYSIS

Estimates from included articles were either extracted or calculated and then pooled to produce a combined estimate of the association of trichomoniasis with each adverse birth outcome using the random effects model. Heterogeneity was assessed using the I² statistic and Cochran's Q test.

MAIN RESULTS

Literature search produced 1658 publications after removal of duplicates (n = 770), with five additional publications identified by hand search. After screening titles and abstracts for relevance, full text of 84 studies was reviewed and 19 met inclusion criteria for meta-analysis. Significant associations were found between trichomoniasis and preterm delivery (OR 1.27; 95% CI 1.08-1.50), prelabour rupture of membranes (OR 1.87; 95% CI 1.53-2.29) and low birthweight (OR 2.12; 95% CI 1.15-3.91).

CONCLUSIONS

Trichomoniasis in pregnant women is associated with preterm delivery, prelabour rupture of membranes and low birthweight. Rigorous studies are needed to determine the impact of universal trichomoniasis screening and treatment during pregnancy on reducing perinatal morbidity.

TWEETABLE ABSTRACT

This systematic review and meta-analysis found that in the setting of pregnancy, trichomoniasis is significantly associated with multiple adverse birth outcomes, including preterm delivery, low birthweight, and prelabour rupture of membranes.

Platelet gene therapy induces robust immune tolerance even in a primed model via peripheral clonal deletion of antigen-specific T cells

While platelet-specific gene therapy is effective in inducing immune tolerance to a targeted protein, how the reactivity of pre-existing immunity affects the efficacy, and whether CD8 T cells were involved in tolerization, is unclear. In this study, ovalbumin (OVA) was used as a surrogate protein. Platelet-OVA expression was introduced by 2bOVA lentivirus transduction of Sca-1⁺ cells from either wild-type (WT)/CD45.2 or OT-II/CD45.2 donors followed by transplantation into OVA-primed WT/CD45.1 recipients preconditioned with 6.6 Gy of irradiation. Sustained platelet-OVA expression was achieved in >85% of OVA-primed recipients but abolished in animals with high-reactive pre-existing immunity. As confirmed by OVA rechallenge and skin graft transplantation, immune tolerance was achieved in 2bOVA-transduced recipients. We found that there is a negative correlation between platelet-OVA expression and the percentage of OVA-specific CD4 T cells and a positive correlation with the OVA-specific regulatory T (Treg) cells. Using the OT-I/WT model, we showed that antigen-specific CD8 T cells were partially deleted in recipients after platelet-targeted gene transfer. Taken together, our studies demonstrate that robust antigen-specific immune tolerance can be achieved through platelet-specific gene therapy via peripheral clonal deletion of antigen-specific CD4 and CD8 T effector cells and induction of antigen-specific Treg cells. There is an antagonistic dynamic process between immune responses and immune tolerance after platelet-targeted gene therapy.

In vivo enrichment of genetically manipulated platelets for murine hemophilia B gene therapy

Our previous studies have demonstrated that platelet-targeted factor IX (FIX) gene therapy can introduce sustained platelet-FIX expression in hemophilia B (FIX^null ) mice. In this study, we aimed to enhance platelet-FIX expression in FIX^null mice with O⁶ -methylguanine-DNA-methyltransferase (MGMT)-mediated in vivo drug selection of transduced cells under nonmyeloablative preconditioning. We constructed a novel lentiviral vector (2bF9/MGMT lentivirus vector), which harbors dual genes, the FIX gene driven by the αIIb promoter (2bF9) and the MGMT P140K gene under the murine stem cell virus promoter. Platelet-FIX expression in FIX^null mice was introduced by 2bF9/MGMT-mediated hematopoietic stem cell transduction and transplantation. The 2bF9/MGMT-transduced cells were effectively enriched after drug selection by O⁶ -benzylguanine/1,3-bis-2-chloroethyl-1-nitrosourea. There were a 2.9-fold higher FIX antigen and a 3.7-fold higher FIX activity in platelets, respectively, posttreatment compared with pretreatment. When a 6-hr tail bleeding test was used to grade the bleeding phenotype, the clotting time in treated animals was 2.6 ± 0.5 hr. In contrast, none of the FIX^null control mice were able to clot within 6 hr. Notably, none of the recipients developed anti-FIX antibodies after gene therapy. One of four recipients developed a low titer of inhibitors when challenged with rhF9 together with adjuvant. In contrast, all FIX^null controls developed inhibitors after the same challenge. Anti-FIX immunoglobulin G were barely detectable in recipients (1.08 ± 0.54 µg/ml), an 875-fold lower level than in the FIX^null controls. Our data demonstrate that using the MGMT-mediated drug selection system in 2bF9 gene therapy can significantly enhance therapeutic platelet-FIX expression, resulting in sustained phenotypic correction and immune tolerance in FIX^null mice.

The impact of GPIbα on platelet-targeted FVIII gene therapy in hemophilia A mice with pre-existing anti-FVIII immunity

Essentials Platelet-specific FVIII gene therapy is effective in hemophilia A mice even with inhibitors. The impact of platelet adherence via VWF/GPIbα binding on platelet gene therapy was investigated. GPIbα does not significantly affect platelet gene therapy of hemophilia A with inhibitors. Platelet gene therapy induces immune tolerance in hemophilia A mice with pre-existing immunity. SUMMARY: Background We have previously demonstrated that von Willebrand factor (VWF) is essential in platelet-specific FVIII (2bF8) gene therapy of hemophilia A (HA) with inhibitory antibodies (inhibitors). At the site of injury, platelet adherence is initiated by VWF binding to the platelet GPIb complex. Objective To investigate the impact of GPIbα on platelet gene therapy of HA with inhibitors. Methods Platelet-FVIII expression was introduced by 2bF8 lentivirus (2bF8LV) transduction of hematopoietic stem cells (HSCs) from GPIbαnull (Ibnull ) mice or rhF8-primed FVIIInull (F8null ) mice followed by transplantation into lethally irradiated rhF8-primed F8null recipients. Animals were analyzed by flow cytometry, FVIII assays and the tail bleeding test. Results After transplantation, 99% of platelets were derived from donors. The macrothrombocytopenia phenotype was maintained in F8null mice that received 2bF8LV-transduced Ibnull HSCs (2bF8-Ibnull /F8null ). The platelet-FVIII expression level in 2bF8-Ibnull /F8null recipients was similar to that obtained from F8null mice that received 2bF8LV-transduced F8null HSCs (2bF8-F8null /F8null ). The tail bleeding test showed that the remaining hemoglobin level in the 2bF8-Ibnull /F8null group was significantly higher than in the F8null control group, but there was no significant difference between the 2bF8-Ibnull /F8null and 2bF8-F8null /F8null groups. The half-life of inhibitor disappearance time was comparable between the 2bF8-Ibnull /F8null and 2bF8-F8null /F8null groups. The rhF8 re-challenge did not elicit a memory immune response once inhibitor titers dropped to undetectable levels after 2bF8 gene therapy. Conclusion GPIbα does not significantly impact platelet gene therapy of HA with inhibitors. 2bF8 gene therapy restores hemostasis and promotes immune tolerance in HA mice with pre-existing immunity.

Platelet Gene Therapy Promotes Targeted Peripheral Tolerance by Clonal Deletion and Induction of Antigen-Specific Regulatory T Cells

Delivery of gene therapy as well as of biologic therapeutics is often hampered by the immune response of the subject receiving the therapy. We have reported that effective gene therapy for hemophilia utilizing platelets as a delivery vehicle engenders profound tolerance to the therapeutic product. In this study, we investigated whether this strategy can be applied to induce immune tolerance to a non-coagulant protein and explored the fundamental mechanism of immune tolerance induced by platelet-targeted gene delivery. We used ovalbumin (OVA) as a surrogate non-coagulant protein and constructed a lentiviral vector in which OVA is driven by the platelet-specific αIIb promoter. Platelet-specific OVA expression was introduced by bone marrow transduction and transplantation. Greater than 95% of OVA was stored in platelet α-granules. Control mice immunized with OVA generated OVA-specific IgG antibodies; however, mice expressing OVA in platelets did not. Furthermore, OVA expression in platelets was sufficient to prevent the rejection of skin grafts from CAG-OVA mice, demonstrating that immune tolerance developed in platelet-specific OVA-transduced recipients. To assess the mechanism(s) involved in this tolerance we used OTII mice that express CD4⁺ effector T cells specific for an OVA-derived peptide. After platelet-specific OVA gene transfer, these mice showed normal thymic maturation of the T cells ruling against central tolerance. In the periphery, tolerance involved elimination of OVA-specific CD4⁺ effector T cells by apoptosis and expansion of an OVA-specific regulatory T cell population. These experiments reveal the existence of natural peripheral tolerance processes to platelet granule contents which can be co-opted to deliver therapeutically important products.

Immune tolerance induced by platelet-targeted factor VIII gene therapy in hemophilia A mice is CD4 T cell mediated

Essentials The immune response is a significant concern in gene therapy. Platelet-targeted gene therapy can restore hemostasis and induce immune tolerance. CD4 T cell compartment is tolerized after platelet gene therapy. Preconditioning regimen affects immune tolerance induction in platelet gene therapy.

SUMMARY

Background Immune responses are a major concern in gene therapy. Our previous studies demonstrated that platelet-targeted factor VIII (FVIII) (2bF8) gene therapy together with in vivo drug selection of transduced cells can rescue the bleeding diathesis and induce immune tolerance in FVIIInull mice. Objective To investigate whether non-selectable 2bF8 lentiviral vector (LV) for the induction of platelet-FVIII expression is sufficient to induce immune tolerance and how immune tolerance is induced after 2bF8LV gene therapy. Methods Platelet-FVIII expression was introduced by 2bF8LV transduction and transplantation. FVIII assays and tail bleeding tests were used to confirm the success of platelet gene therapy. Animals were challenged with rhF8 to explore if immune tolerance was induced after gene therapy. Treg cell analysis, T-cell proliferation assay and memory B-cell-mediated ELISPOT assay were used to investigate the potential mechanisms of immune tolerance. Results We showed that platelet-FVIII expression was sustained and the bleeding diathesis was restored in FVIIInull mice after 2bF8LV gene therapy. None of the transduced recipients developed anti-FVIII inhibitory antibodies in the groups preconditioned with 660 cGy irradiation or busulfan plus ATG treatment even after rhF8 challenge. Treg cells significantly increased in 2bF8LV-transduced recipients and the immune tolerance developed was transferable. CD4+ T cells from treated animals failed to proliferate in response to rhF8 re-stimulation, but memory B cells could differentiate into antibody secreting cells in 2bF8LV-transduced recipients. Conclusion 2bF8LV gene transfer without in vivo selection of manipulated cells can introduce immune tolerance in hemophilia A mice and this immune tolerance is CD4+ T cell mediated.

Proteolysis of plasminogen activator inhibitor-1 by Yersinia pestis remodulates the host environment to promote virulence

Essentials Effect of plasminogen activator inhibitor (PAI)-1 on plague and its Y. pestis cleavage is unknown. An intranasal mouse model of infection was used to determine the role of PAI-1 in pneumonic plague. PAI-1 is cleaved and inactivated by the Pla protease of Y. pestis in the lung airspace. PAI-1 impacts both bacterial outgrowth and the immune response to respiratory Y. pestis infection. Click to hear Dr Bock discuss pathogen activators of plasminogen.

SUMMARY

Background The hemostatic regulator plasminogen activator inhibitor-1 (PAI-1) inactivates endogenous plasminogen activators and aids in the immune response to bacterial infection. Yersinia pestis, the causative agent of plague, produces the Pla protease, a virulence factor that is required during plague. However, the specific hemostatic proteins cleaved by Pla in vivo that contribute to pathogenesis have not yet been fully elucidated. Objectives To determine whether PAI-1 is cleaved by the Pla protease during pneumonic plague, and to define the impact of PAI-1 on Y. pestis respiratory infection in the presence or absence of Pla. Methods An intranasal mouse model of pneumonic plague was used to assess the levels of total and active PAI-1 in the lung airspace, and the impact of PAI-1 deficiency on bacterial pathogenesis, the host immune response and plasmin generation following infection with wild-type or ∆pla Y. pestis. Results We found that Y. pestis cleaves and inactivates PAI-1 in the lungs in a Pla-dependent manner. The loss of PAI-1 enhances Y. pestis outgrowth in the absence of Pla, and is associated with increased conversion of plasminogen to plasmin. Furthermore, we found that PAI-1 regulates immune cell recruitment, cytokine production and tissue permeability during pneumonic plague. Conclusions Our data demonstrate that PAI-1 is an in vivo target of the Pla protease in the lungs, and that PAI-1 is a key regulator of the pulmonary innate immune response. We conclude that the inactivation of PAI-1 by Y. pestis alters the host environment to promote virulence during pneumonic plague.

The important role of von Willebrand factor in platelet-derived FVIII gene therapy for murine hemophilia A in the presence of inhibitory antibodies

BACKGROUND

Our previous studies have demonstrated that targeting FVIII expression to platelets results in FVIII storage together with von Willebrand factor (VWF) in platelet α-granules and that platelet-derived FVIII (2bF8) corrects the murine hemophilia A phenotype even in the presence of high-titer anti-FVIII inhibitory antibodies (inhibitors).

OBJECTIVE

To explore how VWF has an impact on platelet gene therapy for hemophilia A with inhibitors.

METHODS

2bF8 transgenic mice in the FVIII(-/-) background (2bF8(tg+/-) F8(-/-) ) with varying VWF phenotypes were used in this study. Animals were analyzed by VWF ELISA, FVIII activity assay, Bethesda assay and tail clip survival test.

RESULTS

Only 18% of 2bF8(tg+/-) F8(-/-) VWF(-/-) animals, in which VWF was deficient, survived the tail clip challenge with inhibitor titers of 3-8000 BU mL(-1) . In contrast, 82% of 2bF8(tg+/-) F8(-/-) VWF(+/+) mice, which had normal VWF levels, survived tail clipping with inhibitor titers of 10-50,000 BU mL(-1) . All 2bF8(tg+/-) F8(-/-) VWF(-/-) mice without inhibitors survived tail clipping and no VWF(-/-) F8(-/-) mice survived this challenge. Because VWF is synthesized by endothelial cells and megakaryocytes and is distributed in both plasma and platelets in peripheral blood, we further investigated the effect of each compartment of VWF on platelet-FVIII gene therapy for hemophilia A with inhibitors. In the presence of inhibitors, 42% of animals survived tail clipping in the group with plasma-VWF and 50% survived in the platelet-VWF group.

CONCLUSION

VWF is essential for platelet gene therapy for hemophilia A with inhibitors. Both platelet-VWF and plasma-VWF are required for optimal platelet-derived FVIII gene therapy for hemophilia A in the presence of inhibitors.

In vivo enrichment of genetically manipulated platelets corrects the murine hemophilic phenotype and induces immune tolerance even using a low multiplicity of infection

BACKGROUND

Our previous studies have demonstrated that platelet-specific gene delivery to hematopoietic stem cells can induce sustained therapeutic levels of platelet factor VIII (FVIII) expression in mice with hemophilia A.

OBJECTIVE

In this study, we aimed to enhance platelet FVIII expression while minimizing potential toxicities.

METHODS

A novel lentiviral vector (LV), which harbors dual genes, the FVIII gene driven by the αIIb promoter (2bF8) and a drug-resistance gene, the MGMT(P140K) cassette, was constructed. Platelet FVIII expression in mice with hemophilia A was introduced by transduction of hematopoietic stem cells and transplantation. The recipients were treated with O(6)-benzylguanine followed by 1,3-bis-2 chloroethyl-1-nitrosourea monthly three or four times. Animals were analyzed by using polymerase chain reaction (PCR), quantitative PCR, FVIII:C assays, and inhibitor assays. Phenotypic correction was assessed by tail clipping tests and rotational thromboelastometry analysis.

RESULTS

Even using a low multiplicity of infection of 1 and a non-myeloablative conditioning regimen, after in vivo selection, the levels of platelet FVIII expression in recipients increased to 4.33 ± 5.48 mU per 10(8) platelets (n = 16), which were 19.7-fold higher than the levels obtained from the recipients before treatment. Quantitative PCR results confirmed that 2bF8/MGMT-LV-transduced cells were effectively enriched after drug-selective treatment. Fifteen of 16 treated animals survived tail clipping. Blood loss and whole blood clotting time were normalized in the treated recipients. Notably, no anti-FVIII antibodies were detected in the treated animals even after recombinant human B-domain deleted FVIII challenge.

CONCLUSION

we have established an effective in vivo selective system that allows us to enrich 2bF8LV-transduced cells, enhancing platelet FVIII expression while reducing the potential toxicities associated with platelet gene therapy.

Factor VIII inhibitors: von Willebrand factor makes a difference in vitro and in vivo

BACKGROUND

The important association between von Willebrand factor (VWF) and factor VIII (FVIII) has been investigated for decades, but the effect of VWF on the reactivity of FVIII inhibitory antibodies, referred to as inhibitors, is still controversial.

OBJECTIVE

To investigate the interaction among VWF, FVIII and FVIII inhibitory antibodies.

METHODS

Three sources of inhibitors were used for in vitro studies, including the plasma from immunized VWF(null) FVIII(null) mice, purified plasma IgG from human inhibitor patients, or human monoclonal antibody from inhibitor patients' B-cell clones. Inhibitors were incubated with recombinant human FVIII (rhFVIII) either with or without VWF. The remaining FVIII activity was determined by chromogenic assay and inhibitor titers were determined. For in vivo studies, inhibitors and rhFVIII were infused into FVIII(null) or VWF(null) FVIII(null) mice followed by a tail clip survival test.

RESULTS

VWF has a dose-dependent protective effect on FVIII, limiting inhibitor inactivation of FVIII in both mouse and human samples. A preformed complex of VWF with FVIII provides more effective protection from inhibitors than competitive binding of antibodies and VWF to FVIII. The protective effect of VWF against FVIII inactivation by inhibitors was further confirmed in vivo by infusing inhibitors and FVIII into FVIII(null) or VWF(null) FVIII(null) mice followed by a tail clip survival test.

CONCLUSION

Our results demonstrate that VWF exerts a protective effect, reducing inhibitor inactivation of FVIII, both in vitro and in vivo.

Lentivirus-mediated platelet gene therapy of murine hemophilia A with pre-existing anti-factor VIII immunity

BACKGROUND

The development of inhibitory antibodies, referred to as inhibitors, against exogenous factor VIII in a significant subset of patients with hemophilia A remains a persistent challenge to the efficacy of protein replacement therapy. Our previous studies using the transgenic approach provided proof-of-principle that platelet-specific expression could be successful in treating hemophilia A in the presence of inhibitory antibodies.

OBJECTIVE

To investigate a clinically translatable approach for platelet gene therapy of hemophilia A with pre-existing inhibitors.

METHODS

Platelet FVIII expression in preimmunized FVIII(null) mice was introduced by transplantation of lentivirus-transduced bone marrow or enriched hematopoietic stem cells. FVIII expression was determined with a chromogenic assay. The transgene copy number per cell was quantitated with real-time PCR. Inhibitor titer was measured with the Bethesda assay. Phenotypic correction was assessed by the tail clipping assay and an electrolytically induced venous injury model. Integration sites were analyzed with linear amplification-mediated PCR.

RESULTS

Therapeutic levels of platelet FVIII expression were sustained in the long term without evoking an anti-FVIII memory response in the transduced preimmunized recipients. The tail clip survival test and the electrolytic injury model confirmed that hemostasis was improved in the treated animals. Sequential bone marrow transplants showed sustained platelet FVIII expression resulting in phenotypic correction in preimmunized secondary and tertiary recipients.

CONCLUSIONS

Lentivirus-mediated platelet-specific gene transfer improves hemostasis in mice with hemophilia A with pre-existing inhibitors, indicating that this approach may be a promising strategy for gene therapy of hemophilia A even in the high-risk setting of pre-existing inhibitory antibodies.

Intravascular recovery of VWF and FVIII following intraperitoneal injection and differences from intravenous and subcutaneous injection in mice

Intravenous infusion studies in humans suggest that both von Willebrand factor (VWF) and factor VIII (FVIII) remain intravascular in contrast to other coagulation proteins. We explored whether infusion of VWF and FVIII by either intraperitoneal (i.p.) or subcutaneous (s.c.) injection would result in efficient absorption of these large proteins into the vascular circulation. FVIII(null) or VWF(null) mice were infused with plasma-derived or recombinant VWF and/or FVIII by i.p., s.c., or intravenous (i.v.) injection. Both VWF and FVIII were absorbed into the blood circulation after i.p. injection with a peak between 2 and 4 h at levels similar to those observed in mice infused intravenously. In contrast, neither VWF nor FVIII was detected in the plasma following s.c. injection. Although i.v. injection achieved peak plasma levels quickly, both human VWF and FVIII rapidly decreased during the first 2 h following i.v. injection. Following both i.v. and i.p. infusion of VWF, the multimeric structure of circulating VWF was similar to that observed in the infusate. These results demonstrate that both VWF and FVIII can be efficiently absorbed into the blood circulation following i.p., but not s.c. injection, indicating that i.p. administration could be an alternative route for VWF or FVIII infusion.

MUC1 is a novel regulator of ErbB1 receptor trafficking

ErbB receptors are key regulators of cell survival and growth in normal and transformed tissues. The oncogenic glycoprotein MUC1 is a binding partner and substrate for erbB1 and MUC1 expression can potentiate erbB-dependent signal transduction. After receptor activation, erbB1 is typically downregulated via an endocytic pathway that results in receptor degradation or recycling. We report here that MUC1 expression inhibits the degradation of ligand-activated erbB1. Through the use of both RNAi-mediated knock down and overexpression constructs of MUC1, we show that MUC1 expression inhibits erbB1 degradation after ligand treatment in breast epithelial cells. This MUC1-mediated protection against erbB1 degradation can increase total cellular pools of erbB1 over time. Biotinylation of surface proteins demonstrates that cell-surface associated erbB1 receptor is protected by MUC1 against ligand-induced degradation, although this is accompanied by an increase in erbB1 internalization. The MUC1-mediated protection against degradation occurs with a decrease in EGF-stimulated ubiquitination of erbB1, and an increase in erbB1 recycling. These data indicate that MUC1 expression is a potent regulator of erbB1 receptor stability upon activation and may promote transformation through the inhibition of erbB1 degradation.

GABA-opioid interactions in the globus pallidus: [D-Ala2]-Met-enkephalinamide attenuates potassium-evoked GABA release after nigrostriatal lesion

The motor signs of Parkinson's disease have been partly attributed to an overinhibition of the external globus pallidus (GP) that results from hyperactivity of striatopallidal GABA/enkephalinergic neurons. The goals of this study were to measure basal levels of extracellular fluid GABA in the GP of normal cats, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated parkinsonian cats and cats spontaneously recovered from MPTP-induced parkinsonism, and to examine the effects of opioid receptor activation on potassium (K+)-evoked GABA release in the GP in these animals. Basal GP GABA levels were increased 75% from normal in parkinsonian animals 1 week after MPTP administration and returned to control levels in recovered animals 6 weeks after MPTP administration. No significant differences were observed in K+-evoked GABA release across conditions. The opioid receptor agonist [D-Ala2]-Met-Enkephalinamide (DALA) significantly attenuated K+-evoked GABA release in the GP of MPTP-treated symptomatic and recovered cats, but had no significant effect on GABA release in normal animals. These data show that basal GP GABA levels are elevated coincident with expression of parkinsonian signs and return to normal in animals that have functionally compensated for a nigrostriatal lesion. DALA-induced inhibition of pallidal GABA release after a dopamine-depleting lesion, suggests that enkephalin may attenuate GABA release in the GP specifically after striatal dopamine loss.

A tissue sealant based on reactive multifunctional polyethylene glycol

A rapidly gelling synthetic tissue sealant was developed from tetra-succinimidyl and tetra-thiol-derivatized polyethylene glycol (PEG). The two reagents were dissolved in aqueous buffers at 20% (w/v) solids and sprayed on the tissue site, with the use of a sprayer/mixer device. Good adhesion to collagen membranes, PTFE grafts, and carotid artery was observed in vitro. In a burst test on collagen membranes with a 2-mm orifice defect, the gel sustained fluid pressures of 125 +/- 36 mm Hg (n = 18), fivefold greater than capillary blood pressure and one-half that observed in hypertension. On 0.4-mm-diameter puncture defects in PTFE grafts, pressures of 390-490 mm Hg were sustained, and on 0.6-0.9-mm puncture defects in carotid arteries, pressures of 490 to 840 mm Hg were sustained. In vitro data corresponded to results in vivo, where bleeding in rabbit arteries was stopped immediately in five out of six trials. A significant reduction in time to hemostasis and blood loss, compared to controls, was observed. Carotid artery and subcutaneous implant data in rabbits showed that the formula was compatible with biological tissue. Rapid gelling and effective sealing were dependent on the presence of active succinimidyl ester and thiol groups on PEG. HPLC and chemical substitution methods were useful in predicting whether batches of derivatized PEG would perform satisfactorily.

Tyrosine hydroxylase and dopamine transporter expression in residual dopaminergic neurons: potential contributors to spontaneous recovery from experimental Parkinsonism

1-Methyl-4-phenyl-1,2,3,6-tetrahyrdropyridine (MPTP)-exposed cats develop severe Parkinsonism that spontaneously resolves in 4-6 weeks. The present study examined the extent to which compensatory changes in tyrosine hydroxylase (TH) and dopamine transporter (DAT) gene and protein expression may underlie this behavioral recovery. In normal cats, TH and DAT protein levels were higher in the dorsal vs. ventral striatum. Expression of DAT and TH mRNA was higher in substantia nigra pars compacta (SNc) than in the ventral tegmental area (VTA). In symptomatic parkinsonian animals, DAT and TH protein levels were significantly decreased in all striatal areas studied. TH and DAT mRNA expression in residual SNc neurons were decreased a mean 32% and 38%, respectively. DAT gene expression in residual VTA neurons in symptomatic animals was decreased 30% whereas TH gene expression was unaffected. In spontaneously recovered cats, TH protein levels were significantly higher than the levels in symptomatic cats only in the ventral striatum, whereas no increase in DAT protein levels were observed in any striatal area. Residual neurons in most ventral mesencephalic regions of recovered cats had increased TH mRNA expression but not increased DAT gene expression, compared with symptomatic animals. Thus, increased TH protein and mRNA and suppression of DAT protein and mRNA expression in the striatum and ventral mesencephalon were associated with functional recovery from MPTP-induced parkinsonism.

Ultrastructural telepathology--remote EM-diagnostic via Internet

New collaboratory opportunities in ultrastructural research and diagnostics are now available on the Internet through the combination of digital image acquisition, remote operation of modern digitally controlled and automated electron microscopes, and the development of software specifically tailored for collaboratory needs. Remote experts can examine samples directly, and unique instruments can be utilized from anywhere. In the case of diagnostic dilemmas, the second-opinion expert is no longer constrained by problems inherent in the interpretation of preselected images. The remote examiner can independently choose the area of interest on the sample as well as select the appropriate magnification for an accurate diagnosis. With these capabilities and together with teleconferencing tools and securely accessible databases on-line, telepathology can provide increased effectiveness and support for diagnostics, research, and teaching in many areas. The authors report their experience with remote electron microscope diagnoses of pathological samples using two different dynamic imaging systems and discuss the main technical issues encountered. It appears that only minor technical issues need to be resolved before ultrastructural telepathology can be promoted for routine use in areas with high-speed Internet access.

Transgenic MUC1 interacts with epidermal growth factor receptor and correlates with mitogen-activated protein kinase activation in the mouse mammary gland

MUC1 is a large (>400 kDa), heavily glycosylated transmembrane protein that is aberrantly expressed on greater than 90% of human breast carcinomas and subsequent metastases. The precise function of MUC1 overexpression in tumorigenesis is unknown, although various domains of MUC1 have been implicated in cell adhesion, cell signaling, and immunoregulation. Stimulation of the MDA-MB-468 breast cancer line as well as mouse mammary glands with epidermal growth factor results in the co-immunoprecipitation of MUC1 with a tyrosine-phosphorylated protein of approximately 180 kDa. We have generated transgenic lines overexpressing full-length (MMF), cytoplasmic tail deleted (DeltaCT), or tandem repeat deleted (DeltaTR)-human MUC1 under the control of the mouse mammary tumor virus promoter to further examine the role of MUC1 in signaling and tumorigenesis. Immunoprecipitation experiments revealed that full-length transgenic MUC1 physically associates with all four erbB receptors, and co-localizes with erbB1 in the lactating gland. Furthermore, we detected a sharp increase in ERK1/2 activation in MUC1 transgenic mammary glands compared with Muc1 null and wild-type animals. These results point to a novel function of increased MUC1 expression, potentiation of erbB signaling through the activation of mitogenic MAP kinase pathways.

Alterations in expression of messenger RNAs encoding two isoforms of glutamic acid decarboxylase in the globus pallidus and entopeduncular nucleus in animals symptomatic for and recovered from experimental Parkinsonism

Glutamic acid decarboxylase (GAD65, GAD67) mRNA expression was measured in the globus pallidus (GP) and entopeduncular nucleus (ENTO) of normal, and MPTP-lesioned cats symptomatic for and recovered from MPTP-induced Parkinsonism. In the ENTO of symptomatic cats, GAD65 and GAD67 mRNA expression were both significantly increased, while only GAD67 gene expression was increased in the GP. Levels of gene expression for both isoforms were normal in the GP and ENTO of spontaneously recovered animals. Increased expression of GAD65/67 mRNA in the ENTO corresponded with expression of Parkinsonian signs, suggesting a contribution of both isoforms to ENTO functioning and perhaps a greater contribution of GAD67 expression to GP functioning.

Evaluation of a motion fidelity criterion with visual scene changes

An experiment examined how visual scene and platform motion variations affected a pilot's ability to perform altitude changes. Pilots controlled a helicopter model in the vertical axis and moved between two points 32-ft apart in a specified time. Four factors were varied: visual-scene spatial frequency, visual-scene background, motion-filter gain, and motion-filter natural frequency. Drawing alternating black and white stripes of varying widths between the two extreme altitude points varied visual-scene spatial frequency. The visual-scene background varied by either drawing the stripes to fill the entire field of view or by placing the stripes on a narrow pole with a natural sky and ground plane behind the pole. Both the motion-filter gain and natural frequency were varied in the motion platform command software. Five pilots evaluated all combinations of the visual and motion variations. The results showed that only the motion-filter natural frequency and visual-scene background affected pilot performance and their subjective ratings. No significant effects of spatial frequency or motion system gain were found for the values examined in this tracking task. A previous motion fidelity criterion was found to still be a reasonable predictor of motion fidelity.

Cooperative induction of mammary tumorigenesis by TGFalpha and Wnts

We previously reported that multiparous WAP-TGFalpha transgenic mice develop mammary gland carcinomas with complete incidence. TGFalpha-induced tumors appear stochastically and with relatively long latency, indicating an additional requirement for other genetic alterations. To identify genes that cooperate with TGFalpha in mammary tumorigenesis, we used a retroviral insertion approach featuring a cloned and infectious hybrid MMTV (C3H/Mtv-1; (Shackleford and Varmus, 1988)). Tumor latency was decreased approximately 30% in MMTV-infected WAP-TGFalpha transgenic animals compared to noninfected transgenic controls, and > 30% of the corresponding tumors displayed evidence of integrated C3H/Mtv-1 DNA. PCR-based analyses of DNAs from two virus-infected, transgenic tumors revealed integration of hybrid MMTV in 3' untranslated exons of the Wnt-1 or Wnt-3 oncogenes. Moreover, Northern blots confirmed dramatic induction of Wnt-1 or Wnt-3 transcripts in the respective tumors, indicating that MMTV integration resulted in activated expression of these genes. Semiquantitative RT-PCR analyses showed that overexpression of Wnt-1 or Wnt-3 was a common occurrence in MMTV-infected WAP-TGFalpha tumors, and some noninfected WAP-TGFalpha tumors also showed evidence of elevated Wnt-3 transcripts. Collectively, these results reveal cooperative induction of mammary gland tumorigenesis by simultaneous deregulation of EGF-like (TGFalpha) and Wnt growth factors.

Striatal enkephalin gene expression does not reflect parkinsonian signs

Loss of striatal dopamine has been associated with an increase in striatal enkephalin expression. However, the relationship between increased striatal enkephalin expression and the manifestation of parkinsonian motor deficits is not clear. Administration of MPTP to cats produces a severe parkinsonian condition from which the animals spontaneously recover. Using in situ hybridization histochemistry, preproenkephalin (PPE) mRNA expression was examined in the striatum of cats when normal, symptomatic for or spontaneously recovered from MPTP-induced parkinsonism. In all areas of the striatum, PPE mRNA levels were significantly elevated in animals exhibiting severe parkinsonian motor deficits and remained elevated even after recovery of gross motor functioning. These results show that striatal PPE gene expression and parkinsonian motor deficits are not directly correlated.

Biocompatibility and degradation of collagen bone anchors in a rabbit model

Bone anchors are used to fasten tendons and ligaments to bone during reconstructive surgery. Although metal anchors are often used, an anchor that could resorb and permit normal bone regeneration would be advantageous. The objective of the study was to evaluate the biocompatibility and degradation of bone anchors that consist of collagen-based bodies, ceramic washers, and polyester sutures. Eighteen rabbits underwent bilateral implantations in the distal femoral condyles. Nine animals received glutaraldehyde-crosslinked fibrillar collagen bone anchors (FC) and nine received glutaraldehyde-crosslinked fibrillar collagen bone anchors containing tricalcium phosphate (FC-TCP). Three animals per group were sacrificed at postimplantation weeks 1, 6, and 12. One femur from each rabbit was evaluated histologically, and the contralateral side underwent biomechanical pull-out testing. Histological evaluation of the implant site indicated that the FC and FC-TCP bone anchors were both biocompatible. The FC-TCP formulation degraded earlier than the FC formulation, and FC-TCP showed significant degradation at 6 weeks; the FC and FC-TCP formulations both showed similar amounts of degradation at 12 weeks. The degrading anchor bodies appeared to be osteoconductive as evidenced by new bone ingrowth into the degrading collagen matrices without a fibrous interface. These results suggest that collagen-based bone anchors have potential as bioresorbable orthopedic implants.

Adenoviral-mediated gene transfer of interleukin-6 in rat lung enhances antiviral immunoglobulin A and G responses in distinct tissue compartments

The effect of IL-6 transgene expression following lung gene transfer on anti-adenovirus humoral responses of immunoglobulin (Ig) G and A both in the lung and peripheral blood was investigated. Lung infection by a control adenovirus caused an increased level of circulating anti-adenoviral IgG antibodies. However, the magnitude of this response was many times higher in the peripheral blood of rats receiving an adenovirus engineered to express IL-6 transgene. In comparison, much lower levels of anti-adenoviral IgG were detected in the bronchoalveolar fluids of rats receiving either virus. In contrast, there was no detectable level of anti-adenoviral IgA in the peripheral blood in any cases, yet significantly detectable levels of anti-adenoviral IgA were measured in the lung. The levels of this IgA were much higher in the lung of rats expressing IL-6 than in the lung of control animals (15 times higher by day 14). Our findings thus provide evidence that IL-6 plays a significant role in enhancing specific airways mucosal IgA and systemic IgG responses during local lung viral infection, and provide the rationale for using IL-6 locally at mucosa sites as an immune adjuvant for antiviral vaccination program.

Differential recovery of sensorimotor function in GM1 ganglioside-treated vs. spontaneously recovered MPTP-treated cats: partial striatal dopaminergic reinnervation vs. neurochemical compensation

Administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to cats results in a parkinsonian syndrome characterized by rigidity, akinesia, bradykinesia, decreased response to external sensory stimuli and depletion of nigrostriatal dopamine. Cats spontaneously recover gross sensorimotor functions despite little recovery of the dopaminergic innervation of the striatum. In contrast, GM1 ganglioside administration accelerates gross behavioral recovery and causes an increased dopaminergic innervation of the striatum. This study examined whether these two recovery conditions are characterized by different degrees of functional recovery. Cats were trained to perform a sensorimotor reaching task prior to MPTP exposure and were then re-tested on the task 6 weeks later after spontaneously recovering gross motor functioning or after 6 weeks of GM1 treatment. Gross motor recovery was similar in both groups. However, the spontaneously recovered cats had significant difficulty in performing the task while GM1-treated cats performed normally. GM1-treated cats also had significant increases in striatal [3H]mazindol binding compared to spontaneously recovered cats. These results suggest that while gross motor functions may improve to a similar extent with spontaneous and GM1-induced recovery from experimental parkinsonism, complex sensorimotor behavior recovers to different extents under the different recovery conditions. More complete behavioral recovery may depend upon at least a partial recovery of striatal dopaminergic terminals rather than neurochemical compensation.

Dynamic expression and activation of ERBB receptors in the developing mouse mammary gland

The complex system of ERBB receptors and ligands is implicated in growth and differentiation of the mammary gland. However, it has not been comprehensively examined in this dynamic tissue. Combined RNA and protein analyses of glands in different stages from virgin to involution revealed differential expression of the four ERBB receptors, as well as distinctive patterns of ERBB ligand expression that suggested specialized function. ERBB localization was linked to mammary gland function. Thus, in the virgin gland, ERBB1 and ERBB2 were colocalized to all major cell types during ductal morphogenesis but differentially localized in the mature gland. All four ERBB receptors were restricted to epithelia in the differentiated gland. Analyses of ERBB tyrosine phosphorylation provided strong evidence of interaction between the four receptors in this physiological context. Thus, exogenous EGF induced stage-dependent transphosphorylation of ERBB2-4 as well as ERBB1, whereas endogenous phosphorylation of all four receptors peaked in late pregnancy and lactation.

Improved local delivery of TGF-beta2 by binding to injectable fibrillar collagen via difunctional polyethylene glycol

To overcome rapid diffusion and clearance from the implant site and to increase stability, recombinant transforming growth factor beta2 (TGF-beta2) was covalently bound to injectable bovine dermal fibrillar collagen (FC) and its activity compared to admixed TGF-beta2. Covalent binding was achieved in a two-step procedure: First, TGF-beta2 was reacted with the difunctional polyethylene glycol (PEG) linker, and then the PEG-attached TGF-beta2 (PEG-TGF-beta2) was bound to the fibrillar collagen (FC-PEG-TGF-beta2). Initial binding of TGF-beta2 to difunctional succinimidyl glutarate (D-SG-PEG) or succinimidyl propionate polyethylene glycol (D-SE-PEG) linkers was completed after reacting for 8 or 10 min as monitored by reverse-phase high-performance liquid chromatography. After reaction with injectable fibrillar collagen, extraction of unbound PEG-TGF-beta2 and Western blot analysis, using a TGF-beta specific antibody, demonstrated that at least 85% of the TGF-beta2 was bound to the fibrillar collagen. The activity of PEG-TGF-beta2 was fully stable in phosphate-buffered saline at 4 degrees C and 37 degrees C for at least up to 4 weeks. Unmodified TGF-beta2 mixed with fibrillar collagen was completely inactivated after 1 week of incubation, as measured by the mink lung epithelial cell (Mv1Lu) growth inhibition assay. Formulations of FC-PEG-TGF-beta2 containing 40 microg/ mL TGF-beta2 were implanted subcutaneously into rats and analyzed after days 7, 21, and 42. All TGF-beta2-containing formulations showed the TGF-beta typical fibroblastic response at the day 7 time point. Covalent binding of TGF-beta2 to collagen with both difunctional PEG crosslinkers resulted in a significantly stronger and longer-lasting TGF-beta2 response than that observed with admixed formulations of collagen and TGF-beta. The TGF-beta response with FC-PEG-TGF-beta2 lasted up to day 42 but was not seen after day 7 for TGF-beta2 admixed to FC. These findings clearly demonstrate that TGF-beta2 remains fully active after being covalently bound to collagen via difunctional PEG. In addition, covalent binding potentiates and prolongs in vivo TGF-beta responses and stabilizes the TGF-beta in vitro. Results suggest that this method of formulation could be useful to stabilize and deliver similar peptide growth factors or biologically active agents.

Transgenic mice reveal roles for TGFalpha and EGF receptor in mammary gland development and neoplasia

Transforming growth factor-alpha (TGFalpha)4 and/or the EGF receptor (EGFR) are frequently overexpressed by human and rodent breast tumors, as well as tumor-derived cell lines. Additionally, various observations suggest a role for TGFalpha and the EGFR signaling system in normal mouse mammary gland development. Recently, several laboratories have established TGFalpha transgenic mice with which to study the role of this growth factor in normal and neoplastic mammary biology. Examination of these mice revealed that overexpression of TGFalpha has profound consequences for this tissue. Most strikingly, transgenic mice expressing TGFalpha under the control of tissue-specific and nonspecific promoters stochastically developed focal mammary tumors with an incidence and latency that was markedly affected by pregnancy. Most TGFalpha-induced tumors were well-differentiated adenomas/adenocarcinomas, although some were undifferentiated and locally invasive. Distant metastases were only occasionally observed. Administration of the genotoxic carcinogen, 7,12-dimethylbenzanthracene (DMBA), dramatically accelerated mammary tumorigenesis induced by the TGFalpha transgene, raising the possibility that TGFalpha acts as a promoter in this tissue. Mice harboring dual transgenes encoding TGFalpha and either wild-type ERBB2 or c-myc displayed markedly accelerated tumorigenesis compared to mice carrying any of the single transgenes alone, indicative of potent cooperativity. Moreover, tumorigenesis in the bitransgenic mice was less dependent on pregnancy, and tumors were generally more malignant in appearance. Finally, TGFalpha also affected mammary gland dynamics. TGFalpha transgenic mice consistently displayed precocious alveolar development, were variably impaired with respect to lactation, and showed markedly reduced postlactional involution. As a result, the glands of multiparous females accumulated hyperplastic lesions that generally resembled milk-producing alveoli. Limited data support the hypothesis that these lesions were precursors to TGFalpha-induced tumors. In summary, these various findings underscore the potential importance of TGFalpha for cellular differentiation and transformation in the mammary gland. They also establish TGFalpha transgenic mice as a powerful model with which to study the role of EGFR signaling molecules in this dynamic tissue.

Characterization of the mouse transforming growth factor alpha gene: its expression during eyelid development and in waved 1 tissues

The spontaneous mouse waved 1 (wa1) mutation is allelic with the transforming growth factor alpha (TGF-alpha) gene and produces phenotypes similar to those of TGF-alpha knockout mice. Here, we show that TGF-alpha mRNA and protein levels are measurable in wa1 tissues but reduced 5- to 30-fold relative to wild type. Because the wa1-coding sequence is identical to that of the normal mRNA, wa1 is not a null mutation. Nuclear run-on analyses revealed decreased transcription of the TGF-alpha gene in wa1 tissues, but the sequence of a 3.2-kb 5' flanking fragment containing the promoter was unaltered. Moreover, pulsed field gel electrophoresis analysis did not reveal alterations within 750 kb upstream or 350 kb downstream of the gene, and chromosome 6 was karyotypically normal. Hence, we speculate that the wa1 mutation may be subtle and/or reside at a greater distance from the TGF-alpha gene. TGF-alpha deficiency elicits a spectrum of variably penetrant eye anomalies in wa1 and knockout mice that are associated with open eyes at birth. We found that late-gestation wa1 and TGF-alpha-null embryos display a significant delay in eyelid closure, although the eyes of most embryos fuse prior to birth. In situ hybridization localized TGF-alpha expression to the advancing margins of the eyelid epithelium and epidermal growth factor receptor expression throughout the eyelid and corneal epithelia. These results suggest that eye problems observed in TGF-alpha-deficient adult mice arise from premature exposure and trauma to open eyes during or following parturition.

Vector-derived expression of recombinant rat interleukin-6

Rat interleukin-6 (IL-6) cDNA, coding for an important inflammation- and immune-regulatory polypeptide cytokine, was cloned into the novel expression vector pH6EX3 which directs the synthesis of inserted genes as a fusion protein with histidine hexapeptide (HH). The resultant vector (pRIL6.992) was shown to produce significant amounts of recombinant rat IL-6 fusion protein with HH at its N-terminus in various strains of Escherichia coli. The expression of the HH-IL-6 fusion protein was demonstrated to be under the control of the tac promoter and could be induced by IPTG. This protein was isolated from bacterial inclusion bodies and purified to homogeneity in a one-step procedure by affinity chromatography using a nickel-chelating column. The HH-IL-6 fusion protein isolated in this manner was biologically active as determined by hepatocyte stimulation and B9 hybridoma growth assays. Further, this activity was neutralized with a polyclonal antiserum raised against rat IL-6 protein generated in a novel fashion from rabbits infected with a recombinant human type-5 adenovirus vector expressing rat IL-6 protein (Ad5E3rIL6). The recombinant HH-IL-6 protein was then used to boost Ad5E3rIL6-immunized rabbits. This resulting antiserum was shown to neutralize recombinant and natural rat and murine IL-6 bioactivity in vitro and was useful in Western blot analysis and immunohistochemistry of rat IL-6.

Inhibition of mammary gland involution is associated with transforming growth factor alpha but not c-myc-induced tumorigenesis in transgenic mice

Deregulated expression of transforming growth factor alpha (TGF-alpha) or c-myc has been implicated in the genesis of human breast cancer. To better characterize the role of these molecules in this disease, we generated transgenic mice that express TGF-alpha or c-myc under control of the mouse whey acidic protein (WAP) promoter. We then compared the resulting mammary gland neoplasia in these mice and in previously described mice expressing a metallothionein-driven TGF-alpha transgene. Nonvirgin female mice in all transgenic lineages developed mammary tumors with 100% incidence but variable latency. Among TGF-alpha lines, mean survival time correlated with the level of transgene expression, and the average life spans of high-expressing WAP-TGF-alpha and WAP-c-myc mice were similarly reduced. The majority of TGF-alpha-induced tumors were relatively well-differentiated adenomas and adenocarcinomas; in contrast, WAP-c-myc tumors were poorly differentiated, solid carcinomas with a minority of adenocarcinomas. Most TGF-alpha and all c-myc-induced tumors were transplantable, but lung metastases were infrequently observed in all transgenic lines. WAP-TGF-alpha-induced tumors, in marked contrast to those induced by WAP-c-myc, displayed frequent induction of cyclin D1 mRNA, suggesting that expression of this gene may complement that of TGF-alpha during mammary tumor development. Expression of TGF-alpha also induced precocious development of pregnant glands and delayed or inhibited mammary involution. As a result, multiparious MT-TGF-alpha and especially WAP-TGF-alpha females accumulated large numbers of hyperplastic alveolar nodules that resembled the more differentiated TGF-alpha-induced tumors. Finally, coexpression of WAP-c-myc and WAP-TGF-alpha transgenes markedly decreased tumor latency, increased tumor growth, and even induced mammary tumors in virgin female and male mice. These findings provide further evidence for the importance of deregulated TGF-alpha expression in multistage carcinogenesis, and they suggest that in the mammary gland the mechanism of TGF-alpha-induced transformation may depend on postlactational survival of differentiated epithelium. They also provide evidence of a potent tumorigenic collaboration between TGF-alpha and c-myc in mammary epithelium.

Intra-articular morphine after arthroscopic knee operation

Reports on pain relief with intra-articular morphine after arthroscopic knee operation are conflicting. To assess the long-term antinociceptive effect of intraarticular morphine, we studied pain at rest, pain on standing and ability to walk for 7 days after intraarticular injection of bupivacaine 100 mg (group 1, n = 11), bupivacaine 100 mg and morphine 1 mg (group 2, n = 10) and bupivacaine 100 mg and morphine 3 mg (group 3, n = 10) at the end of operation. Pain and walking were assessed by visual analogue and walking scales, respectively. Pain was treated with morphine i.v. in the recovery room and Tylenol No. 3 after discharge. Assessments were made before operation, and 1, 3, 6 and 12 h after injection and on days 1-7 after operation. There were significant differences between the groups in pain scores (pain at rest, P < 0.05; pain on standing, P < 0.01). The pain scores in group 3 were lower than those in group 1. The differences in pain scores at rest were significant at 12 h and on day 1 after operation and differences in pain scores on standing were significant at 12 h and on days 1 and 2 after operation. The scores in group 2 were intermediate between those in groups 1 and 3. The walking scores in group 3 were significantly better than those in group 1 at 12 h. The amount of analgesics received in groups 2 and 3 was significantly less than that in group 1 until day 3 after operation.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of intravenous ranitidine and metoclopramide on behavior, cognitive function, and affect

Both ranitidine and metoclopramide produce neuropsychiatric side effects. Concomitant use of these drugs preoperatively may produce adverse behavioral and emotional changes. Therefore, in 123 unpremedicated patients undergoing tubal occlusion, behavior, cognitive function, and affect were studied before and after a 2-min intravenous injection of placebo (n = 30), ranitidine 50 mg (n = 32), metoclopramide 10 mg (n = 30), or both ranitidine 50 mg and metoclopramide 10 mg (n = 31). Cognitive function was evaluated by the responses to 11 statements devised to assess attitude toward anesthesia and surgery. Affect was assessed by the word chosen out of 11 word-pairs as best describing the feelings at the time. After ranitidine injection, one patient seemed restless and five seemed drowsy. The changes were associated with subjective feelings of agitation (P < 0.05) and restlessness (P < 0.05). After metoclopramide injection, 6 (20%) developed akathisia, 13 (43.3%) seemed restless, and 8 (26.7%) seemed drowsy. The changes were associated with subjective sensation of jumpiness (P < 0.01) and discomfort (P < 0.05). When both ranitidine and metoclopramide were injected, 10 (32.3%) developed akathisia, 4 (12.4%) seemed restless, and 11 (35.5%) seemed drowsy. The changes were associated with subjective feelings of agitation (P < 0.05), jumpiness (P < 0.05), restlessness (P < 0.01), and upset (P < 0.05). Akathisia, a side effect of metoclopramide, seemed to be more prominent when ranitidine was added.

Quantitative EEG analysis during cardiac surgery in a case of spontaneous recall

A case of spontaneous postoperative recall of intraoperative events during tricuspid valvuloplasty is presented. In this case, EEG activity was continuously monitored and quantitatively processed to detect brain dysfunction during the procedure. Anesthetic maintenance was provided by fentanyl, isoflurane and midazolam. A retrospective analysis of the relative power distribution, median frequency and fast/slow ratio was conducted to characterize the recall and non-recall periods during the surgery. Analysis of the quantitative descriptors suggested that no specific EEG pattern was associated with the periods of recall. The use of several anesthetics with different effects on the EEG precludes the establishment of a single relationship between descriptors and changes in vigilance during episodes of recall.

Side effects during continuous epidural infusion of morphine and fentanyl

Respiratory effects, nausea, somnolence, and pruritus were compared during a 48-hr period of continuous epidural morphine (n = 34) and fentanyl (n = 32) infusion in 66 patients following elective total replacement of the hip or knee joint. Respiratory effects were assessed by PaCO2. Side effects were assessed by visual analogue scale and considered to be present when the score was above 30. Assessment was made at preoperative visits then 3, 6, 12, 24, 36, and 48 hr after the epidural injection. The bolus dose and subsequent infusion rate were 3,900 +/- 1,300 micrograms and 427 +/- 213 micrograms.hr-1 for morphine, and 85 +/- 46 micrograms and 56 +/- 27 micrograms.hr-1 for fentanyl. Pain relief was similar in both groups. In the morphine group, PaCO2 elevation and nausea occurred over a period of more than 12 hr (P less than 0.05). In the fentanyl group, there was no PaCO2 change, and nausea was confined to the first few hours. Nausea was more severe (P less than 0.01 at six hours and more frequent (24 hr cumulative incidence, 53 vs 28%, P less than 0.05) in the morphine group. Somnolence was prominent within several hours in two-thirds of patients in both groups. Somnolence continued to decline thereafter in the morphine group, but it was demonstrable in approximately half of the patients throughout the second day in the fentanyl group. The incidence was higher in the fentanyl group at the 48th hr (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Human activities as sources of volatile organic compounds in residential environments

The objectives of the present work were to investigate techniques for the continuous, qualitative monitoring of VOCs and to see how VOC levels were influenced by normal household activities. Three different methods were investigated to measure the VOC levels: infrared spectroscopy, photoionization detection, and gas chromatographic analysis of absorbent tube samples. Results were presented that related changes in levels of VOCs to various human activities commonly occurring in residences, and data were presented that indicated activities such as cooking, arts and crafts, cleaning floors, and painting contributed to short-term increases in VOC levels. VOC levels were diminished by turning on the air conditioner. Results on the effect of humidity on VOCs, both in homes and controlled chambers, were reported.

Evaluation of Drosophila melanogaster as an alternative animal for studying the neurotoxicity of heavy metals

Heavy metals cause irreversible neurobehavioral damage in many developing mammals, but the mechanisms of this damage are unknown. The influence of three heavy metal compounds, triethyllead chloride, lead acetate and cadmium chloride, on lethality, development, behavior and learning was studied using the fruit fly, Drosophila melanogaster. This animal was used because it allows hundreds of subjects to be assayed very easily in individual experiments and because it is a system in which toxicological questions might be answered by using the techniques of modern molecular genetics. When triethyllead chloride, lead acetate or cadmium chloride was placed in the medium, the larval LC50 (+/- standard error) was found to be 0.090 +/- 0.004, 6.60 +/- 0.64 and 0.42 +/- 0.04 mM, respectively. Each of the tested compounds produced a dose-related delay in development. In particular, they caused a delay in the development of larvae to pupae. When larvae were reared on medium containing triethyllead chloride (0.06 mM), lead acetate (3.07 mM) or cadmium chloride (0.11 mM), phototaxis, locomotion and learning were not inhibited. Since significant neurobehavioral effects were not observed under the experimental conditions used, Drosophila does not appear to be an appropriate animal for the genetic dissection of such effects of heavy metals during development.

Induction of luteal phase defect with clomiphene citrate

The effect of clomiphene citrate and progesterone on luteal function in infertile women was studied. Endometrial biopsies were performed in 103 women immediately prior to menstruation. Group 1 (n = 62) had secretory endometrium with a histologic lag time of greater than or equal to 48 hours with respect to the subsequent menses, that is, luteal phase defect. Group 2 (n = 10) had normal histologic characteristics of the secretory phase. Group 3 (n = 31) had anovulatory endometrium. The last group was subdivided into those with polycystic ovary syndrome (n = 9) and those without the characteristic gonadotropin pattern of polycystic ovary syndrome (n = 22). Clomiphene citrate at doses of 50 to 250 mg daily for 5 days was administered for induction of ovulation, timing of ovulation, or treatment of luteal phase defect. An endometrial biopsy was obtained after three ovulatory treatment cycles. Only one fourth of the women with prior luteal phase defect had normalization of the biopsy specimen with clomiphene citrate, while one half of those treated with progesterone had normal specimens. Half of the normally ovulating women had induction of a luteal phase defect with clomiphene citrate. Only women with polycystic ovary syndrome had consistently well-timed endometrial histologic features with clomiphene citrate therapy. Despite successful induction of ovulation, 16 of the other 22 previously anovulatory women had endometrial histologic findings compatible with luteal phase defect. Increasing the clomiphene citrate dosage was unsuccessful in improving endometrial maturation. These results suggest that the use of clomiphene citrate may be associated with a high rate of luteal phase defect induction, except among women with polycystic ovary syndrome. Clomiphene citrate, even at high doses, appears to be ineffective therapy for luteal phase defect.