Integration-deficient lentiviral vectors expressing codon-optimized R338L human FIX restore normal hemostasis in Hemophilia B mice.

Integration-deficient lentiviral vectors (IDLVs) have been shown to transduce a wide spectrum of target cells and organs in vitro and in vivo and to maintain long-term transgene expression in nondividing cells. However, epigenetic silencing of episomal vector genomes reduces IDLV transgene expression levels and renders these safe vectors less efficient. In this article, we describe for the first time a complete correction of factor IX (FIX) deficiency in hemophilia B mice by IDLVs carrying a novel, highly potent human FIX cDNA. A 50-fold increase in human FIX cDNA potency was achieved by combining two mechanistically independent yet synergistic strategies: (i) optimization of the human FIX cDNA codon usage to increase human FIX protein production per vector genome and (ii) generation of a highly catalytic mutant human FIX protein in which the arginine residue at position 338 was substituted with leucine. The enhanced human FIX activity was not associated with liver damage or with the formation of human FIX-directed inhibitory antibodies and rendered IDLV-treated FIX-knockout mice resistant to a challenging tail-clipping assay. A novel S1 nuclease-based B1-quantitative polymerase chain reaction assay showed low levels of IDLV integration in mouse liver. Overall, this study demonstrates that IDLVs carrying an improved human FIX cDNA safely and efficiently cure hemophilia B in a mouse model.

Gene therapy for hemophilia: advancing beyond the first clinical success.

PURPOSE OF REVIEW: Consistently measurable and persistent expression of circulating clotting factor activity, associated with decreased clinical bleeding, has been achieved for the first time in a hemophilia gene therapy trial. This review examines the successes and limitations of this clinical trial for hemophilia B and approaches to advance beyond this milestone. RECENT FINDINGS: Although a self-complementary serotype 8 adeno-associated virus (scAAV8) vector approach directed factor IX expression of up to 6% in a human trial, the apparent need to suppress vector dose-dependent immune-mediated liver inflammation in some patients at the highest dose highlighted the next steps to optimize the risk-benefit of hemophilia gene therapy. The approaches being pursued include manufacturing modifications to eliminate contaminating empty vector capsids, the utilization of factor IX and factor VIII modified transgenes to improve secretion or function of the transgene product, and adjunctive pharmacologic and molecular approaches to overcome limitations imposed by naturally occurring antibodies against vectors and by the large size of the factor VIII gene. SUMMARY: Preclinical data suggest strategies in development may build upon the first gene therapy success and achieve factor IX correction sufficient to prevent bleeding without toxicity and translate success to hemophilia A gene therapy.

Inadvertent Transfer of Murine VL30 Retrotransposons to CAR-T Cells.

For more than a decade, genetically engineered autologous T-cells have been successfully employed as immunotherapy drugs for patients with incurable blood cancers. The active components in some of these game-changing medicines are autologous T-cells that express viral vector-delivered chimeric antigen receptors (CARs), which specifically target proteins that are preferentially expressed on cancer cells. Some of these therapeutic CAR expressing T-cells (CAR-Ts) are engineered via transduction with γ-retroviral vectors (γ-RVVs) produced in a stable producer cell line that was derived from murine PG13 packaging cells (ATCC CRL-10686). Earlier studies reported on the copackaging of murine virus-like 30S RNA (VL30) genomes with γ-retroviral vectors generated in murine stable packaging cells. In an earlier study, VL30 mRNA was found to enhance the metastatic potential of human melanoma cells. These findings raise biosafety concerns regarding the possibility that therapeutic CAR-Ts have been inadvertently contaminated with potentially oncogenic VL30 retrotransposons. In this study, we demonstrated the presence of infectious VL30 particles in PG13 cell-conditioned media and observed the ability of these particles to deliver transcriptionally active VL30 genomes to human cells. Notably, VL30 genomes packaged by HIV-1-based vector particles transduced naïve human cells in culture. Furthermore, we detected the transfer and expression of VL30 genomes in clinical-grade CAR-T cells generated by transduction with PG13 cell-derived γ-retroviral vectors. Our findings raise biosafety concerns regarding the use of murine packaging cell lines in ongoing clinical applications.

Preliminary Clinical Evaluation of Acupuncture Therapy in Patients With Postpartum Sciatica.

INTRODUCTION: This study evaluated clinical outcomes following acupuncture treatment of postpartum sciatica. METHODS: One hundred eleven women with postpartum sciatica were enrolled in an acupuncture group (n = 86) or a control group (n = 25), according to their preference. Participants in the acupuncture group attended acupuncture therapy sessions 3 times a week for 4 weeks, while participants in the control group were assigned to bed rest. Outcome measures included the Roland Disability Questionnaire for sciatica, a visual analog scale for leg pain, and patient-reported perceived recovery. In addition, participants were surveyed after treatment to assess the acceptability of acupuncture therapy. RESULTS: The outcome scores for disability and leg pain were significantly lower in the acupuncture group compared with the control group (P < .05). All 86 women in the treatment group stated that acupuncture improved their well-being after treatment. At one month after treatment, 98% of participants in the treatment group reported recovery compared with 24% of the control group participants (P < .001). After treatment, 95% of lactating women in the acupuncture group believed that acupuncture had no significant interference with breast milk production. No adverse effects of acupuncture were reported. All participants in the acupuncture group stated they would choose acupuncture in case of relapse. However, the recurrence rate of sciatica in the acupuncture group (32%) was comparable to that of the control group (35%) at the one-year follow-up interview. DISCUSSION: Compared with bed rest, acupuncture might be an effective and acceptable strategy to relieve symptoms of postpartum sciatica.

In vivo response to vascular injury in the absence of factor IX: examination in factor IX knockout mice.

INTRODUCTION: Recently, in vitro models of coagulation have called into question the traditional conception of Factor IX as an intrinsic pathway protein, essential to propagation of coagulation but not central to the initiation of hemostatic plug, which has been thought instead to involve TF/FVIIa interactions with factor X and platelets. We hypothesized that the activation of factor IX, and its role in a factor IXa/FVIIa "tenase" complex leading to thrombin generation, plays a more important role than that of TF/FVIIa complex activation of factor X in the early hemostatic response to vascular injury. In vivo modeling is possible because of the generation of factor IX(-/-) mice. MATERIALS AND METHODS: We used two models of arterial vascular injury, histological examination following mechanical carotid artery disruption and intravital microscopy of a mesenteric arteriole subsequent to ferric chloride arteriolar injury to examine mice having complete deficiency of factor IX (FIX(-/-)). RESULTS: Both injury models demonstrate that platelet rich thrombi /hemostatic plug in FIX(-/-) mice is dramatically reduced as compared to wild type mice under conditions of high shear; in fact, no platelet thrombi (>20 mum) were observed in the intravital experiments. Interestingly, the platelet defect is more striking than that described in mice lacking fibrinogen and/or von Willebrand factor. CONCLUSIONS: The results suggest TF/FVIIa-->FX pathway is insufficient for effective platelet aggregation in the presence of high flow, requiring factor IX at the convergence of both intrinsic and extrinsic pathways. Following platelet adhesion, factor IX is required for normal platelet aggregation in vivo, as well as thrombin generation and propagation of occlusive thrombus at the site of vascular injury.

Toward Personalized Gene Therapy: Characterizing the Host Genetic Control of Lentiviral-Vector-Mediated Hepatic Gene Delivery.

The success of lentiviral vectors in curing fatal genetic and acquired diseases has opened a new era in human gene therapy. However, variability in the efficacy and safety of this therapeutic approach has been reported in human patients. Consequently, lentiviral-vector-based gene therapy is limited to incurable human diseases, with little understanding of the underlying causes of adverse effects and poor efficacy. To assess the role that host genetic variation has on efficacy of gene therapy, we characterized lentiviral-vector gene therapy within a set of 12 collaborative cross mouse strains. Lentiviral vectors carrying the firefly luciferase cDNA under the control of a liver-specific promoter were administered to female mice, with total-body and hepatic luciferase expression periodically monitored through 41 weeks post-vector administration. Vector copy number per diploid genome in mouse liver and spleen was determined at the end of this study. We identified major strain-specific contributions to overall success of transduction, vector biodistribution, maximum luciferase expression, and the kinetics of luciferase expression throughout the study. Our results highlight the importance of genetic variation on gene-therapeutic efficacy; provide new models with which to more rigorously assess gene therapy approaches; and suggest that redesigning preclinical studies of gene-therapy methodologies might be appropriate.

Employing a gain-of-function factor IX variant R338L to advance the efficacy and safety of hemophilia B human gene therapy: preclinical evaluation supporting an ongoing adeno-associated virus clinical trial.

Vector capsid dose-dependent inflammation of transduced liver has limited the ability of adeno-associated virus (AAV) factor IX (FIX) gene therapy vectors to reliably convert severe to mild hemophilia B in human clinical trials. These trials also identified the need to understand AAV neutralizing antibodies and empty AAV capsids regarding their impact on clinical success. To address these safety concerns, we have used a scalable manufacturing process to produce GMP-grade AAV8 expressing the FIXR338L gain-of-function variant with minimal (<10%) empty capsid and have performed comprehensive dose-response, biodistribution, and safety evaluations in clinically relevant hemophilia models. The scAAV8.FIXR338L vector produced greater than 6-fold increased FIX specific activity compared with wild-type FIX and demonstrated linear dose responses from doses that produced 2-500% FIX activity, associated with dose-dependent hemostasis in a tail transection bleeding challenge. More importantly, using a bleeding model that closely mimics the clinical morbidity of hemophilic arthropathy, mice that received the scAAV8.FIXR338L vector developed minimal histopathological findings of synovitis after hemarthrosis, when compared with mice that received identical doses of wild-type FIX vector. Hemostatically normal mice (n=20) and hemophilic mice (n=88) developed no FIX antibodies after peripheral intravenous vector delivery. No CD8(+) T cell liver infiltrates were observed, despite the marked tropism of scAAV8.FIXR338L for the liver in a comprehensive biodistribution evaluation (n=60 animals). With respect to the role of empty capsids, we demonstrated that in vivo FIXR338L expression was not influenced by the presence of empty AAV particles, either in the presence or absence of various titers of AAV8-neutralizing antibodies. Necropsy of FIX(-/-) mice 8-10 months after vector delivery revealed no microvascular or macrovascular thrombosis in mice expressing FIXR338L (plasma FIX activity, 100-500%). These preclinical studies demonstrate a safety:efficacy profile supporting an ongoing phase 1/2 human clinical trial of the scAAV8.FIXR338L vector (designated BAX335).

Concentrations and potential health hazards of organochlorine pesticides in (shallow) groundwater of Taihu Lake region, China.

A total of 27 shallow groundwater samples were collected from the Taihu Lake region (TLR), to determine the concentrations of 14 organochlorine pesticide (OCP) species, identify their possible sources, and estimate health risk of drinking the shallow groundwater. All OCP species occurred in the shallow groundwater of TLR with high detection frequency except p, p'-dichlorodiphenyldichlorothane (p, p'-DDD) and p, p'-dichlorodiphenyltrichloroethane (p, p'-DDT). DDTs and hexachlorocyclohexanes (HCHs) were the dominant OCP contaminants in the shallow groundwater of TLR, and they account for 44.2% total OCPs. The low α-HCH/γ-HCH ratio, high ß-HCH/(α+γ)-HCH ratio and ß-HCH being the dominant HCH isomers for the majority of samples suggest that the HCHs were mainly from the historical use of lindane after a period of degradation. p, p'-DDE being the dominant DDT metabolite for all the samples indicated that the DDTs were mainly from the historical residues. Compositional analysis also suggested that there were fresh input sources of heptachlors, aldrins and endrins in addition to the historical residues. Correlation analysis indicated the hexachlorobenzene (HCB) impurity in the shallow groundwater of TLR was likely from the historical application of lindane and technical HCH (a mixture of HCH isomers that is produced by photochlorination of benzene). Carcinogenic risk values for α-HCH, heptachlor, heptachlor epoxide, aldrins and dieldrin in the shallow groundwater in majority area of TLR were found to be >10(-6), posing a potentially serious cancer risk to those dependant on shallow groundwater for drinking water.

West Yorkshire Mentor Scheme: teaching and development.

BACKGROUND: The West Yorkshire Mentoring Scheme (WYMS) was created to provide a framework for clinical supervision, teaching and support by foundation year (FY) doctors for final-year medical students. Although established literature highlights the benefits of near-peer teaching, the accompanying mentoring role has little been explored. This study explored the impact of the WYMS for FY doctors and final-year medical students. METHOD: FY1 mentors were individually paired with fifth-year medical students from the University of Leeds. The scheme aims to provide support, teaching and skills development for both mentors and mentees, as students rotate through clinical placements and assistantships. At the end of each academic year, FY1s and medical students are invited to complete an online questionnaire to highlight their experiences. These data were used to explore the impact of the scheme, and thematic analysis was employed to determine the results. RESULTS: Forty-nine medical students and 122 FY1s responded: 98 per cent of mentors and 100 per cent of mentees would recommend the scheme to their peers. Thematic analysis demonstrated that the scheme proved useful in skills development, teaching supervision and increasing preparedness for work. DISCUSSION: WYMS is well received, beneficial and an excellent, local adjunct to clinical placements. It is of significant value to final-year students and their FY mentors, assisting in the development of student assistantships and clinical placement design. For FY doctors, it is a rewarding scheme that develops essential attributes of time management, communication and leadership for mentors and for the junior doctors who organise the scheme.

Skeletal tissue engineering using mesenchymal or embryonic stem cells: clinical and experimental data.

INTRODUCTION: Mesenchymal stem cells (MSCs) can be obtained from a wide variety of tissues for bone tissue engineering such as bone marrow, adipose, birth-associated, peripheral blood, periosteum, dental and muscle. MSCs from human fetal bone marrow and embryonic stem cells (ESCs) are also promising cell sources. AREAS COVERED: In vitro, in vivo and clinical evidence was collected using MEDLINE® (1950 to January 2014), EMBASE (1980 to January 2014) and Google Scholar (1980 to January 2014) databases. EXPERT OPINION: Enhanced results have been found when combining bone marrow-derived mesenchymal stem cells (BMMSCs) with recently developed scaffolds such as glass ceramics and starch-based polymeric scaffolds. Preclinical studies investigating adipose tissue-derived stem cells and umbilical cord tissue-derived stem cells suggest that they are likely to become promising alternatives. Stem cells derived from periosteum and dental tissues such as the periodontal ligament have an osteogenic potential similar to BMMSCs. Stem cells from human fetal bone marrow have demonstrated superior proliferation and osteogenic differentiation than perinatal and postnatal tissues. Despite ethical concerns and potential for teratoma formation, developments have also been made for the use of ESCs in terms of culture and ideal scaffold.

Stem cells combined with bone graft substitutes in skeletal tissue engineering.

INTRODUCTION: Bone grafting is used to repair large bone defects and autograft is recognised as producing the best clinical outcome, which is partly due to its cellular component. When autograft is unavailable, allograft and bone graft substitutes can be used; however, they rely on the host bed to provide cellular osteogenic activity. AREAS COVERED: Bone graft substitutes have the potential to benefit from the addition of stem cells aimed at enhancing the rate and quality of defect repair. Mesenchymal stem cells (MSCs) can be isolated from bone marrow or periosteum and culture expanded. Other sources of primary cells include muscle, adipose tissue, human umbilical cord and the pluripotent embryonic stem cells (ESCs). EXPERT OPINION: MSCs isolated from bone marrow have been the best characterised approach for osteogenic differentiation. Their use with synthetic scaffolds such as hydroxyapatite and tricalcium phosphate has produced promising clinical results. MSCs derived from adipose tissue, muscle or human umbilical cord cells combined with various scaffolds are an attractive option. Further in vivo and clinical investigation of their potential is required. Pluripotent ESCs have a theoretical advantage over MSCs; however, purification, cell-specific differentiation, effective delivery vehicles-scaffolds and teratogenesis control are still under in vitro and in vivo evaluation.

[Experimental study on electric impedance of acupuncture based on the midnight-noon ebb-flow theory].

OBJECTIVE: Relationship among three point selection methods based on the midnight-noon ebb-flow theory, namely Najia fa (day- prescription of acupoints), Nazi fa (hour-prescription of acupoints) and Yangzi Shike Zhuxue fa (point-open method based on the mother and son relation as well as the hours and its divisions), were approved in the article, which provided the scientific validity of the correlation among three point selection methods of midnight-noon ebb-flow theory. METHODS: Electric impedance on relevant acupoints of 30 health subjects on the period of the day of Zishi (from 11:00 p.m. to 1:00 a.m.), Maoshi (from 5:00 a.m. to 7:00 a.m.), Wushi (from 11:00 a.m. to 1:00 p.m.) and Youshi (from 5:00 p.m. to 7:00 p.m.) were tested with NQ-1B conductivity meter. And statistical analysis was made on the testing results. RESULTS: The daily average value of the method of Najia fa in 1 circle of the midnight-noon ebb-flow theory was 0.459omega, the value of the method of Nazi fa was 0.553omega, and the Yangzi Shike Zhuxue fa was 0.533omega. At the same time, it presented a tendency of first raising and then declining from Zishi to Youshi with the peak appears at Maoshi and the valley at Youshi. The differences of comparison of the average electric impedance between Najia fa and Nazi fa, Najia fa and Yangzi Shike Zhuxue fa were considered statistical significant (both P < 0.001). When 2 values of different methods within the same hours were compared, the value difference between Najia fa and Nazi fa in the time period of Wushi and the difference between Najia fa and Yangzi Shike Zhuxue fa in the time period of Wushi were considered statistical significant (P < 0.001, P < 0.01). CONCLUSION: The changing tendency of electric impedance of different point selection methods based on midnight-noon ebb-flow theory is similar, however, with weak relevance. Moreover, obvious differences can still be found in point location and time selection.

[Effects of applying inorganic P and wheat straw on the microbial biomass P and microbial P concentration in a calcareous soil with low concentration available P].

In an incubation test, a calcareous soil with low concentration of available P was amended with KH2PO4 (0, 25, 50, and 100 mg P x kg(-1)) and ground wheat straw (5 g C x kg(-1)), and incubated at 25 degrees C for 90 days. The aim was to investigate the change patterns of soil microbial biomass P and microbial P concentration as well as their relationships with soil available P. The results showed that both soil microbial biomass P and microbial P concentration increased with increasing inorganic P addition, with the maximum being 71.37 and 105.34 mg x kg(-1), respectively. The combined application of inorganic P (except 100 mg P x kg(-1)) and wheat straw decreased the soil microbial biomass P and microbial P concentration, being most obvious at early incubation period. Soil microbial biomass P and microbial P concentration had significant positive correlations (P < 0.05) with soil available P (R2 = 0.26 and 0.40, n = 49, respectively). The applied P could rapidly transform into microbial biomass P. The maximum apparent contribution rate of applied P to microbial biomass P was 71%. The added wheat straw could further improve the apparent contribution rate.

Growth hormone: does it have a therapeutic role in fracture healing?

BACKGROUND: The role of growth hormone (GH) in augmenting fracture healing has been postulated for over half a century. GH has been shown to play a role in bone metabolism and this can be mediated directly or indirectly through IGF-I. OBJECTIVES: The use of GH was evaluated as a possible therapeutic agent in augmenting fracture healing. METHOD: A literature search was undertaken on GH and its effect on bone fracture healing primarily using MEDLINE/OVID (1950 to January 2009). Key words and phrases including 'growth hormone', 'insulin like growth factor', 'insulin like growth factor binding protein', 'insulin like growth factor receptor', 'fracture repair', 'bone healing', 'bone fracture', 'bone metabolism', 'osteoblast' and 'osteoclast' were used in different combinations. Manual searches of the bibliography of key papers were also undertaken. RESULTS: Current evidence suggests a positive role of GH on fracture healing as demonstrated by in vitro studies on osteoblasts, osteoclasts and the crosstalk between the two. Animal studies have demonstrated a number of factors influencing the effect of GH in vivo such as dose, timing and method of administration. Application of this knowledge in humans is limited but clearly demonstrates a positive effect on fracture healing. Concern has been raised in the past regarding the safety profile of the pharmacological use of GH when used in critically ill patients. CONCLUSION: The optimal dose and method of administration is still to be determined, and the safety profile of this novel use of GH needs to be investigated prior to establishing its widespread use as a fracture-healing agent.

Statins: under investigation for increasing bone mineral density and augmenting fracture healing.

BACKGROUND: Statins are 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase inhibitors and have been shown to possess anti-lipidaemic properties effective in lowering cholesterol. Recent evidence has suggested beneficial pleiotropic effects, including that of fracture healing, alongside its widely accepted ability to reduce the incidence of cardiovascular disease. OBJECTIVES: A comprehensive review of the recent literature on the effect of statins on bone mineral density and fracture healing. METHODS: Medline/Ovid and EMBASE search and manual search of bibliography of key papers, on the effects of statins on bone metabolism including in vitro and in vivo studies, as well as clinical trials on the effects of statins on bone mineral density and fracture risk. RESULTS/CONCLUSIONS: There is robust in vitro and in vivo evidence to suggest the anabolic effects of statins on bone metabolism. Although evidence in patients with osteoporosis is conflicting, several studies have shown that the use of statins is associated with increases in bone mass density and reduction in fracture risk. Conflicting studies identified may be due to different routes of administration, types of statins employed and low doses used. Taken together, there is strong evidence to suggest that statins have beneficial effects on fracture healing that would support further clinical trials investigating such properties.

Correction of factor IX deficiency in mice by embryonic stem cells differentiated in vitro.

Murine embryonic stem (ES) cells are pluripotent, but significant functional engraftment does not occur when they are introduced into the liver. However, here we demonstrate that functional liver engraftment does occur if the ES cells (from strain 129 mice) are first differentiated in vitro for 7 days in the presence of FGF. Strikingly, when these differentiated cells, termed putative endodermal precursors (PEPs), were injected into their livers, two of six C57BL/6 and four of eight BALB/c factor IX (F-IX)-deficient mice survived for >7 days, even though the recipients were of a different strain and, in the case of the BALB/c recipients, had a complete MHC mismatch. F-IX was detected in all six of the PEP-injected survivors. Two mice subsequently died of causes unrelated to F-IX; the others survived until death at 38 or 115 days after the transplantation. No uninjected control F-IX-deficient mice survived for >7 days. Large confluent regions of sinusoidal PEP engraftment were demonstrated by immunofluorescence in the long-term BALB/c survivors. The PEP engraftment was not associated with detectable cell fusion, and the transplantation was accompanied with only a low incidence of teratoma formation.

Creation of a mouse expressing defective human factor IX.

The majority of cases of human hemophilia B are the result of missense mutations in the coagulation factor IX gene and defective circulating factor IX is detectable in most patients. The available mouse factor IX knockout models of hemophilia B (FIXKO mouse) reproduce the bleeding phenotype of human hemophilia B, but because the models produce no factor IX they fail to reproduce the dominant human phenotype. We have created a human factor IX mouse model of hemophilia B (R333Q-hFIX mouse) by homologous recombination in embryonic stem cells. The mouse expresses no mouse factor IX, but instead expresses a missense mutant human factor IX from the mouse FIX promoter. Mutant human factor IX mRNA transcript and circulating human factor IX are detectable throughout development, but factor IX activity is less than 1% and the mouse exhibits the hemophilic phenotype. When R333Q-hFIX mice were challenged by intramuscular injection of adeno-associated virus expressing human factor IX, factor IX expression without the development of antibodies was observed. In contrast, given the same treatment, FIXKO mice consistently develop antibodies. Our R333Q-hFIX mice strain will complement the FIXKO mice for studying factor IX circulating kinetics and gene therapy.