BMP2 gene transfer induces pericardial effusion and inflammatory response in the ischemic porcine myocardium

Pro-angiogenic gene therapy is being developed to treat coronary artery disease (CAD). We recently showed that bone morphogenetic protein 2 (BMP2) and vascular endothelial growth factor-A synergistically regulate endothelial cell sprouting in vitro. BMP2 was also shown to induce endocardial angiogenesis in neonatal mice post-myocardial infarction. In this study, we investigated the potential of BMP2 gene transfer to improve cardiomyocyte function and neovessel formation in a pig chronic myocardial infarction model. Ischemia was induced in domestic pigs by placing a bottleneck stent in the proximal part of the left anterior descending artery 14 days before gene transfer. Intramyocardial gene transfers with adenovirus vectors (1 × 1012 viral particles/pig) containing either human BMP2 (AdBMP2) or beta-galactosidase (AdLacZ) control gene were performed using a needle injection catheter. BMP2 transgene expression in the myocardium was detected with immunofluorescence staining in the gene transfer area 6 days after AdBMP2 administration. BMP2 gene transfer did not induce angiogenesis or cardiomyocyte proliferation in the ischemic pig myocardium as determined by the quantitations of CD31 or Ki-67 stainings, respectively. Accordingly, no changes in heart contractility were detected in left ventricular ejection fraction and strain measurements. However, BMP2 gene transfer induced pericardial effusion (AdBMP2: 9.41 ± 3.17 mm; AdLacZ: 3.07 ± 1.33 mm) that was measured by echocardiography. Furthermore, an increase in the number of immune cells and CD3+ T cells was found in the BMP2 gene transfer area. No changes were detected in the clinical chemistry analysis of pig serum or histology of the major organs, implicating that the gene transfer did not induce general toxicity, myocardial injury, or off-target effects. Finally, the levels of fibrosis and cardiomyocyte apoptosis detected by Sirius red or caspase 3 stainings, respectively, remained unaltered between the groups. Our results demonstrate that BMP2 gene transfer causes inflammatory changes and pericardial effusion in the adult ischemic myocardium, which thus does not support its therapeutic use in chronic CAD.

SproutAngio: an open-source bioimage informatics tool for quantitative analysis of sprouting angiogenesis and lumen space

Three-dimensional image analyses are required to improve the understanding of the regulation of blood vessel formation and heterogeneity. Currently, quantitation of 3D endothelial structures or vessel branches is often based on 2D projections of the images losing their volumetric information. Here, we developed SproutAngio, a Python-based open-source tool, for fully automated 3D segmentation and analysis of endothelial lumen space and sprout morphology. To test the SproutAngio, we produced a publicly available in vitro fibrin bead assay dataset with a gradually increasing VEGF-A concentration ( https://doi.org/10.5281/zenodo.7240927 ). We demonstrate that our automated segmentation and sprout morphology analysis, including sprout number, length, and nuclei number, outperform the widely used ImageJ plugin. We also show that SproutAngio allows a more detailed and automated analysis of the mouse retinal vasculature in comparison to the commonly used radial expansion measurement. In addition, we provide two novel methods for automated analysis of endothelial lumen space: (1) width measurement from tip, stalk and root segments of the sprouts and (2) paired nuclei distance analysis. We show that these automated methods provided important additional information on the endothelial cell organization in the sprouts. The pipelines and source code of SproutAngio are publicly available ( https://doi.org/10.5281/zenodo.7381732 ).

Decreased Gray-White Matter Contrast of [11C]-PiB Uptake in Cognitively Unimpaired Subjects with Severe Obstructive Sleep Apnea

BACKGROUND

Very recently, cognitively normal, middle-aged adults with severe obstructive sleep apnea (OSA) were shown to have regional cortical amyloid-β deposits. In the normal brain, amyloid tracer (e.g., [11C]-PiB) uptake is observed in white matter (WM) but not in cortical gray matter (GM), resulting in clear GM-WM contrast. There are no reports on possible changes in this contrast in severe OSA.

OBJECTIVES

Evaluate changes in the global [11C]-PiB GM-WM contrast and study if factors reflecting clinical and imaging characteristics are associated with them.

DESIGN AND SETTING

Cross-sectional imaging study.

PARTICIPANTS

19 cognitively intact middle-aged (mean 44 years) patients with severe OSA (Apnea-Hypopnea Index >30/h), carefully selected to exclude any other possible factors that could alter brain health.

MEASUREMENTS

Detailed neuroimaging (amyloid PET, MRI). Signs of possible alterations in amyloid tracer GM-WM contrast and kinetics were studied with static and dynamic [11C]-PiB PET and WM structures with detailed 3.0T MRI.

RESULTS

Static [11C]-PiB PET uptake showed significantly decreased GM-WM contrast in 5 out of 19 patients. This was already clearly seen in visual evaluation and also detected quantitatively using retention indexes. Dynamic imaging revealed decreased contrast due to alterations in trace accumulation in the late phase of [11C]-PiB kinetics. Decreased GM-WM contrast in the late phase was global in nature. MRI revealed no corresponding alterations in WM structures. Importantly, decreased GM-WM contrast was associated with smoking (p = 0.007) and higher Apnea-Hypopnea Index (p = 0.001).

CONCLUSIONS

Severe OSA was associated with decreased GM-WM contrast in amyloid tracer uptake, with significant correlation with clinical parameters of smoking and AHI. The results support and further extend the current understanding of the deleterious effect of severe OSA on proper amyloid clearance, possibly reflecting dysfunction of the brain glymphatic system.

Gene therapy for ischaemic heart disease and heart failure

Gene therapy has been expected to become a novel treatment method since the structure of DNA was discovered in 1953. The morbidity from cardiovascular diseases remains remarkable despite the improvement of percutaneous interventions and pharmacological treatment, underlining the need for novel therapeutics. Gene therapy-mediated therapeutic angiogenesis could help those who have not gained sufficient symptom relief with traditional treatment methods. Especially patients with severe coronary artery disease and heart failure could benefit from gene therapy. Some clinical trials have reported improved myocardial perfusion and symptom relief in CAD patients, but few trials have come up with disappointing negative results. Translating preclinical success into clinical applications has encountered difficulties in successful transduction, study design, endpoint selection, and patient selection and recruitment. However, promising new methods for transducing the cells, such as retrograde delivery and cardiac-specific AAV vectors, hold great promise for myocardial gene therapy. This review introduces gene therapy for ischaemic heart disease and heart failure and discusses the current status and future developments in this field.

BMP6/TAZ-Hippo signaling modulates angiogenesis and endothelial cell response to VEGF

The BMP/TGFβ-Smad, Notch and VEGF signaling guides formation of endothelial tip and stalk cells. However, the crosstalk of bone morphogenetic proteins (BMPs) and vascular endothelial growth factor receptor 2 (VEGFR2) signaling has remained largely unknown. We demonstrate that BMP family members regulate VEGFR2 and Notch signaling, and act via TAZ-Hippo signaling pathway. BMPs were found to be regulated after VEGF gene transfer in C57/Bl6 mice and in a porcine myocardial ischemia model. BMPs 2/4/6 were identified as endothelium-specific targets of VEGF. BMP2 modulated VEGF-mediated endothelial sprouting via Delta like Canonical Notch Ligand 4 (DLL4). BMP6 modulated VEGF signaling by regulating VEGFR2 expression and acted via Hippo signaling effector TAZ, known to regulate cell survival/proliferation, and to be dysregulated in cancer. In a matrigel plug assay in nude mice BMP6 was further demonstrated to induce angiogenesis. BMP6 is the first member of BMP family found to directly regulate both Hippo signaling and neovessel formation. It may thus serve as a target in pro/anti-angiogenic therapies.

Comparative transcriptome analysis of matched primary and distant metastatic ovarian carcinoma

BACKGROUND

High grade serous ovarian carcinoma (HGSOC) is the most common subtype of epithelial ovarian cancers (EOC) with poor prognosis. In most cases EOC is widely disseminated at the time of diagnosis. Despite the optimal cytoreductive surgery and chemotherapy most patients develop chemoresistance, and the 5-year overall survival being only 25-35%.

METHODS

Here we analyzed the gene expression profiles of 10 primary HGSOC tumors and 10 related omental metastases using RNA sequencing and identified 100 differentially expressed genes.

RESULTS

The differentially expressed genes were associated with decreased embryogenesis and vasculogenesis and increased cellular proliferation and organismal death. Top upstream regulators responsible for this gene signature were NR5A1, GATA4, FOXL2, TP53 and BMP7. A subset of these genes were highly expressed in the ovarian cancer among the cancer transcriptomes of The Cancer Genome Atlas. Importantly, the metastatic gene signature was suggestive of poor survival in TCGA data based on gene enrichment analysis.

CONCLUSION

By comparing the gene expression profiles of primary HGSOC tumors and their matched metastasis, we provide evidence that a signature of 100 genes is able to separate these two sample types and potentially predict patient survival. Our study identifies functional categories of genes and transcription factors that could play important roles in promoting metastases and serve as markers for cancer prognosis.

Magnetically Coated Bioabsorbable Stents for Renormalization of Arterial Vessel Walls after Stent Implantation

The insertion of a stent in diseased arteries is a common endovascular procedure that can be compromised by the development of short- and long-term inflammatory responses leading to restenosis and thrombosis, respectively. While treatment with drugs, either systemic or localized, has decreased the incidence of restenosis and thrombosis these complications persist and are associated with a high mortality in those that present with stent thrombosis. We reasoned that if stents could be made to undergo accelerated endothelialization in the deployed region, then such an approach would further decrease the occurrence of stent thrombosis and restenosis thereby improving clinical outcomes. Toward that objective, the first step necessitated efficient capture of progenitor stem cells, which eventually would become the new endothelium. To achieve this objective, we engineered intrinsic ferromagnetism within nonmagnetizable, biodegradable magnesium (Mg) bare metal stents. Mg stents were coated with biodegradable polylactide (PLA) polymer embedding magnetizable iron-platinum (FePt) alloy nanoparticles, nanomagnetic particles, ⁿMags, which increased the surface area and hence magnetization of the stent. ⁿMags uniformly distributed on stents enabled capture, under flow, up to 50 mL/min, of systemically injected iron-oxide-labeled (IO-labeled) progenitor stem cells. Critical parameters enhancing capture efficiency were optimized, and we demonstrated the generality of the approach by showing that ⁿMag-coated stents can capture different cell types. Our work is a potential paradigm shift in engineering stents because implants are rendered as tissue in the body, and this "natural stealthiness" reduces or eliminates issues associated with pro-inflammatory immune responses postimplantation.

Relevance of an academic GMP Pan-European vector infra-structure (PEVI)

In the past 5 years, European investigators have played a major role in the development of clinical gene therapy. The provision of substantial funds by some individual member states to construct GMP facilities makes it an opportune time to network available gene therapy GMP facilities at an EU level. The integrated coordination of GMP production facilities and human skills for advanced gene and genetically-modified (GM) cell therapy, can dramatically enhance academic-led "First-in-man" gene therapy trials. Once proof of efficacy is gathered, technology can be transferred to the private sector which will take over further development taking advantage of knowledge and know-how. Complex technical challenges require existing production facilities to adapt to emerging technologies in a coordinated manner. These include a mandatory requirement for the highest quality of production translating gene-transfer technologies with pharmaceutical-grade GMP processes to the clinic. A consensus has emerged on the directions and priorities to adopt, applying to advanced technologies with improved efficacy and safety profiles, in particular AAV, lentivirus-based and oncolytic vectors. Translating cutting-edge research into "First-in-man" trials require that pre-normative research is conducted which aims to develop standard assays, processes and candidate reference materials. This research will help harmonise practices and quality in the production of GMP vector lots and GM-cells. In gathering critical expertise in Europe and establish conditions for interoperability, the PEVI infrastructure will contribute to the demands of the advanced therapy medicinal products* regulation and to both health and quality of life of EU-citizens.

Gene therapy: the first approved gene-based medicines, molecular mechanisms and clinical indications

As gene therapy has matured from clinical trials to the first commercial products, understanding of the mechanisms of gene delivery has increased tremendously. This has also been reflected in viral vector development, creating a number of new approaches to tackle issues in transduction efficiency, biodistribution and viral safety. This review will highlight the most important issues and advancements in vector development, administration, surface modification, integration to host genome and safety. The gene therapy products currently available or near market approval, based on p53 expression (Gendicine and Advexin), conditionally replicative adenoviruses (Oncorine) and thymidine kinase + ganciclovir therapy (Cerepro), are introduced with emphasis on the molecular mechanisms of action.

Antegrade flow and peripheral resistance determine the level of endogenous arteriogenesis in patients with superficial femoral artery occlusion

OBJECTIVES

Occlusion in a limb artery leads to impaired blood supply and ischaemia. Collateral artery growth (arteriogenesis) is one of the most effective natural response mechanisms to compensate this pathologic situation. However, it is unknown if clinically important features, like poor run-off, have an impact on compensatory vessel growth.

METHODS

Study population of this retrospective study consisted of 70 patients who suffered from lower limb ischaemia and underwent bypass surgery because of an occlusion of the superficial femoral artery. Clinical data were collected and pre- and postoperative angiograms were reviewed. Number of collateral vessels bypassing the occluded segment was counted. Features of inflow and outflow vessels were recorded.

RESULTS

The mean number of collaterals was 13 + or - 0.5 per patient. In univariate analysis, short daily walking distance, chronic critical leg ischaemia, low ankle brachial index, low number of patent calf arteries and stenosed inflow arteries predicted low number of collateral arteries. In the multivariate analysis, only the quality of inflow and the number of patent calf vessels demonstrated an independent association (P < 0.05) with the number of collaterals.

CONCLUSIONS

Ankle-brachial index, grade of symptoms and daily walking capacity could be used to predict collateral density. Importantly, a good antegrade flow and peripheral runoff seem to have a significant effect on collateral density, implying an impact on the activation of arteriogenesis.

Development of atherosclerotic plaques

Atherosclerosis is a multifactorial disease. A unified model for the lesion development reveals many connections between the response-to-injury hypothesis and the lipid hypothesis. Various cellular uptake mechanisms for native and modified lipoproteins are discussed with respect to foam cell formation and lesion development. The role of arterial smooth muscle cells in atherogenesis is emphasized. Preliminary results of biochemical analyses from the coronary arteries of accidentally died Finnish children and adults reveal that the accumulation of plasma-derived cholesteryl esters in young children began early in childhood, long before the vessels became macroscopically affected and changes in arterial glycosaminoglycans correlated significantly with the accumulation of cholesteryl esters.

PDGF-C and -D and their receptors PDGFR-alpha and PDGFR-beta in atherosclerotic human arteries

BACKGROUND

Platelet derived growth factors (PDGFs) are mitogens for fibroblasts and smooth muscle cells. This growth factor family contains four members PDGF-A, PDGF-B, PDGF-C and PDGF-D. Biology of recently discovered PDGF-C and PDGF-D is not well-established. Here we studied the expression of PDGF-C and PDGF-D and their receptors PDGFR-alpha and PDGFR-beta in normal and atherosclerotic human arteries.

MATERIALS AND METHODS

Human arterial samples from amputations and autopsies were classified according to the atherosclerotic stage and the expression of PDGF-C and PDGF-D proteins and their receptors was studied by immunohistochemistry. In situ hybridization and reverse transcriptase-PCR were used to study mRNA expression.

RESULTS

Both growth factors were expressed in medial smooth muscle cells (SMCs) in normal arteries and atherosclerotic lesions. However, clear differences were found in the expression profiles in endothelium: PDGF-C was strongly expressed in endothelial cells in both normal arteries and lesions whereas PDGF-D was only weakly expressed in endothelium. PDGF-C expression was very prominent in lesion macrophages. PDGF-D was expressed throughout the artery wall in lesions. PDGFR-alpha expression was strong in endothelium and in lesion macrophage-rich areas, whereas PDGFR-beta was mostly expressed in SMCs.

CONCLUSIONS

Our results suggest that PDGF-C may play an important role in endothelium in normal and atherosclerotic arteries and in macrophages in lesions. PDGF-D was expressed in all types of lesions with the same intensity and thus differs from the expression of PDGF-C.

Differences in retinal neovascular tissue and vitreous humour in patients with type 1 and type 2 diabetes

AIMS

The aim of the study was to evaluate the histopathology of neovascular tufts and vitreous samples collected from patients with diabetes.

METHODS

Vitreous samples and neovascular tufts were collected from patients with type 1 (n = 13) and (n = 17) type 2 diabetes with proliferative retinopathy, and from controls with a macular hole (n = 5). Neovessels were analysed using immunohistochemistry and vitreous samples with an enzyme-linked immunosorbent assay (ELISA). The main outcome measure was to examine differences in the levels of growth factors in patients with type 1 and type 2 diabetes with proliferative retinopathy.

RESULTS

Vascular endothelial growth factor (VEGF)-A was most strongly present in the samples from patients with type 1 diabetes. In type 2 diabetes, VEGF-D was more abundantly present than in type 1 diabetes. Angiopoietin (ANG)-2 was also abundantly present. Macrophages and nuclear factor kappa B (NFkappaB) were found, indicating the presence of an inflammatory process in the neovascular tissues.

CONCLUSIONS

VEGF-A and ANG-2 are equally important in the neovascular process in both type 1 and type 2 diabetes. VEGF-D is abundantly present in type 2 diabetes. In order to achieve better control of diabetic retinopathy, it might be beneficial to develop treatments that prevent the actions of ANG-2 and VEGF-D.

Water spin dynamics during apoptotic cell death in glioma gene therapy probed by T1rho and T2rho

Longitudinal and transverse relaxations in the rotating frame, with characteristic time constants T1rho and T2rho, respectively, have potential to provide unique MRI contrast in vivo. On-resonance spin-lock T1rho with different spin-lock field strengths and adiabatic T2rho with different radiofrequency-modulation functions were measured in BT4C gliomas treated with Herpes Simplex Virus thymidine kinase (HVS-tk) gene therapy causing apoptotic cell death. These NMR tools were able to discriminate different treatment responses in tumor tissue from day 4 onward. An equilibrium two-site exchange model was used to calculate intrinsic parameters describing changes in water dynamics. Observed changes included increased correlation time of water associated with macromolecules and a decreased fractional population of this pool. These results are consistent with destructive intracellular processes associated with cell death and the increase of extracellular space during the treatment. Furthermore, association between longer exchange correlation time and decreased pH during apoptosis is discussed. In this study, we demonstrated that T1rho and T2rho MR imaging are useful tools to quantify early changes in water dynamics reflecting treatment response during gene therapy.

Extended release of adenovirus from silica implants in vitro and in vivo

Despite promising preclinical results, the clinical benefits of cancer gene therapy have been modest heretofore. The main obstacle continues to be the level and persistence of gene delivery to sufficiently large areas of the tumor. One approach for overcoming this might entail extended local virus release. We studied the utility of silica gel monoliths for delivery of adenovirus to advanced orthotopic gastric and pancreatic cancer tumors. Initially, the biochemical properties of the silica-virus matrix were studied and nearly linear release as a function of time was detected. Virus stayed infective for weeks at +37 degrees C and months at +4 degrees C, which may facilitate storage and distribution. In vivo, extended release of functional replication deficient and also replication-competent, capsid-modified oncolytic viruses was seen. Treatment of mice with pancreatic cancer doubled their survival (P<0.001). Also, silica gel-based delivery slowed the development of antiadenovirus antibodies.

Respiratory infection recurrence and passive smoking in early atherosclerosis in children and adolescents with type 1 diabetes

BACKGROUND

Optimal glucose control in juvenile type 1 diabetes mellitus is necessary but not sufficient to reduce the burden of cardiovascular events in later life. This emphasizes the importance of searching for other possible risk factors associated with diabetes. We investigated whether recurrent episodes of acute respiratory infections and exposure to tobacco smoke could influence vascular phenotypes for early atherosclerosis in children and adolescents with type 1 diabetes.

MATERIALS AND METHODS

Common carotid artery elasticity and intima-media thickness along with circulating markers of lipid, inflammatory and glycaemic profiles were investigated in up to 98 children and adolescents with type 1 diabetes. The number of clinically manifest acute respiratory tract infections (RTI) during the past year, and the degree of exposure to environmental tobacco smoke (ETS), were assessed by separate questionnaires.

RESULTS

Carotid artery compliance (CAC) was decreased in patients with high (>or= 4/year; n = 22) recurrence of RTI compared to the remaining patients (n = 40; P < 0.05). In a multivariate analysis, the number of RTI during the past year and HbA(1C) were independently associated with decreased CAC (P < 0.05 for both). The inverse relationship between RTI recurrence and CAC was strengthened by frequent exposure to ETS.

CONCLUSIONS

High recurrence of respiratory infections in young type 1 diabetics is associated with increased stiffening of the carotid artery particularly in those often exposed to tobacco smoke.

Progress and prospects: gene therapy clinical trials (part 1)

Over the last two decades gene therapy has moved from preclinical to clinical studies for many diseases ranging from single gene disorders such as cystic fibrosis and Duchenne muscular dystrophy, to more complex diseases such as cancer and cardiovascular disorders. Gene therapy for severe combined immunodeficiency (SCID) is the most significant success story to date, but progress in many other areas has been significant. We asked 20 leaders in the field succinctly to summarize and comment on clinical gene therapy research in their respective areas of expertise and these are published in two parts in the Progress and Prospect series.

SPECT/CT imaging of baculovirus biodistribution in rat

Non-invasive imaging provides essential information regarding the biodistribution of gene therapy vectors and it can also be used for the development of targeted vectors. In this study, we have utilized micro Single-photon emission computed tomography to visualize biodistribution of a (99m)Tc-polylys-ser-DTPA-biotin-labelled avidin-displaying baculovirus, Baavi, after intrafemoral (i.f.), intraperitoneal (i.p.), intramuscular (i.m.) and intracerebroventricular (i.c.v.) administration. The imaging results suggest that the virus can spread via the lymphatic network after different administration routes, also showing accumulation in the nasal area after systemic administration. Extensive expression in the kidneys and spleen was seen after i.p. administration, which was confirmed by reverse transcriptase-polymerase chain reaction and immunohistochemistry. Additionally, transduction of kidneys was seen with i.m. and i.f. administrations. We conclude that baculovirus may be beneficial for the treatment of kidney diseases after i.p. administration route.

Overexpression of VEGF-A induces neovascularization and increased vascular leakage in rabbit eye after intravitreal adenoviral gene transfer

AIM

The aim of this study was to determine dose-response effects of vascular endothelial growth factor A as delivered using an adenoviral vector on vascular growth and pathological changes in the rabbit eye. Moreover, we wanted to develop a large animal model for angioproliferative diseases in the eye.

METHODS

Seventeen New Zealand White rabbits were injected with adenoviral vascular endothelial growth factor-A (AdVEGF-A) intravitreally with different doses (10(9)-10(11) vp). Controls were injected with an empty virus (AdCMV). Some animals had a combination of AdVEGF-A and AdsKDR (a soluble form of the VEGF receptor-2). Animals were killed 6 days after the gene transfer. On the basis of these results, 14 rabbits were injected intravitreally with AdVEGF-A or adenoviral LacZ (AdLacZ) with 10(10) vp in a volume of 0.1 mL. Animals were killed 3, 6, 14 and 28 days after the gene transfer, eyes were removed and analysed histologically.

RESULTS

In enzyme-linked immunosorbent assay (ELISA) analysis, human VEGF-A was present in vitreous humour in all VEGF-A transduced eyes. The amount of VEGF-A showed a dose-dependent increase with the AdVEGF-A dose and was the highest 6 days after the gene transfer. Histologic analyses revealed an increased capillary area and density in the AdVEGF-A eyes when compared with the AdLacZ eyes (P < 0.05). In the AdVEGF-A/AdsKDR eyes the average capillary area was not increased compared with AdLacZ eyes.

CONCLUSION

This model could be useful for large animal studies regarding the pathogenesis of neoangiogenesis and for the development of new therapeutic strategies for angioproliferative diseases of the eye. Our results establish the key role of VEGF-A in the induction of neovascularization and pathological changes in the rabbit eye.

Magnetic resonance imaging of viral particle biodistribution in vivo

We describe here a technique for the visualization of viral vector delivery by magnetic resonance imaging (MRI) in vivo. By conjugating avidin-coated baculoviral vectors (Baavi) with biotinylated ultra-small superparamagnetic iron oxide particles (USPIO), we are able to produce vector-related MRI contrast in the choroid plexus cells of rat brain in vivo over a period of 14 days. Ten microlitres of 2.5 x 10(10) PFU/ml nuclear-targeted LacZ-encoding Baavi with bUSPIO coating was injected into rat brain ventricles and visualized by MRI at 4.7 T. As baculoviruses exhibit restricted cell-type specificity in the rat brain, altered MRI contrast was detected in the choroid plexus of the injected ventricles. No specific signal loss was detected when wild-type baculoviruses or intact biotinylated USPIO particles were injected into the lateral ventricles. Cryosectioned brains were stained for nuclear-targeted beta-galactosidase gene expression, which was found to colocalize with MRI contrast. This study provides the first proof of principle for robust and non-invasive viral vector MRI by using avidin-displaying viruses in vivo. Considering the widespread use of MRI in current medical imaging, the approach is likely to provide numerous future applications in imaging of therapeutic gene transfer.

Gene technology based therapies in the brain

Gene therapy potentially represents one of the most important developments in modern medicine. Gene therapy, especially of cancer, has created exciting and elusive areas of therapeutic research in the past decade. In fact, the first gene therapy performed in a human was not against cancer but was performed to a 14 year old child suffering from adenosine deaminase (ADA) deficiency. In addition to cancer gene therapy there are many other diseases and disorders where gene therapy holds exciting and promising opportunities. These include amongst others gene therapy within the central nervous system and the cardiovascular system. Improvements of the efficiency and safety of gene therapy is the major goal of gene therapy development. After the death of Jesse Gelsinger, the first patient in whom death could be directly linked to the viral vector used for the treatment, ethical doubts were raised about the feasibility of gene therapy in humans. Therefore, the ability to direct gene transfer vectors to specific target cells is also a crucial task to be solved and will be important not only to achieve a therapeutic effect but also to limit potential adverse effects.

Truncated vesicular stomatitis virus G protein improves baculovirus transduction efficiency in vitro and in vivo

Pseudotyping of viral vectors has been widely used to enhance viral transduction efficiency. One of the most popular pseudotyping proteins has been the G-protein of the vesicular stomatitis virus, VSV-G. In the present study, we show that the 21-amino-acid ectodomain with transmembrane and cytoplasmic tail domains of VSV-G (VSV-GED) augments baculovirus-mediated gene delivery in vertebrate cells by aiding viral entry. The VSV-GED pseudotyped virus replicated efficiently in insect cells yielding high titers. Five out of six studied cell lines showed improved transduction, as measured by a number of transduced cells or transgene expression level. Nearly 15-fold increase in the transduction efficiency was detected in rat malignant glioma cells as compared to the control virus. In the rat brain, transgene expression could be detected in the walls of lateral ventricles and in subarachnoid membranes. Increased transduction efficiency was also observed in the rabbit muscle. Our results suggest that VSV-GED enhances baculoviral gene transfer by augmenting gp64-mediated endosomal release. Moreover, no cytotoxicity was associated with improved gene transfer efficiency. Thus, VSV-GED pseudotyping provides a simple means to enhance baculovirus-mediated gene transfer in vitro and in vivo.

VEGF-A, VEGF-D and VEGF-D(DeltaNDeltaC) induced intimal hyperplasia in carotid arteries

BACKGROUND

The role of vascular endothelial growth factors (VEGFs) in intimal hyperplasia and atherogenesis remains unknown. Several studies have suggested that some members of the VEGF family reduce intimal hyperplasia, but others have proposed that VEGFs accelerate restenosis and atherosclerosis. This investigation conducted a comparative study with adenoviruses encoding different VEGFs in a rabbit carotid artery collar model of intimal hyperplasia in order to analyze the role of VEGFs in the formation of intimal hyperplasia.

MATERIALS AND METHODS

Intimal hyperplasia was induced in the carotid arteries of cholesterol fed New Zealand White rabbits using a silastic collar. Adenoviral vectors encoding VEGF-A, VEGF-B, VEGF-C, VEGF-C(DeltaNDeltaC), VEGF-D and VEGF-D(DeltaNDeltaC) were delivered to the adventitia using the collar as a gene delivery device. Adeno-LacZ was used as a control.

RESULTS

A significant (P < 0.01) increase in the intima/media ratio was observed in the arteries transduced with VEGF-A, VEGF-D and VEGF-D(DeltaNDeltaC). There was a significant increase in the number of proliferating cells in the adventitia, media and intima of the VEGF-A, VEGF-D and the VEGF-D(DeltaNDeltaC) transduced arteries. The majority of medial smooth muscle cells in these arteries had a synthetic phenotype. The presence of matrix metalloproteinase-2 (MMP-2) and MMP-9 in the VEGF-A, VEGF-D and the VEGF-D(DeltaNDeltaC) transduced arteries was significantly increased. A significant positive correlation was observed between adventitial angiogenesis and intimal hyperplasia.

CONCLUSIONS

Adventitial delivery of adenoviruses encoding VEGF-A, VEGF-D and VEGF-D(DeltaNDeltaC) increased intimal hyperplasia in the rabbit collar model. Adventitial angiogenesis correlated positively with the intimal hyperplasia. These results indicated that efficient adventitial production of VEGF-A, VEGF-D and VEGF-D(DeltaNDeltaC) can cause thickening of the inner layer of the artery in rabbits.

Gene transfer using the mature form of VEGF-D reduces neointimal thickening through nitric oxide-dependent mechanism

Gene transfer to the vessel wall using vascular endothelial growth factors (VEGFs) has shown therapeutic potential for the treatment of restenosis. In this study, we evaluated the effect of catheter-mediated adenoviral (Ad) gene transfer of the mature form of VEGF-D (VEGF-D(DeltaNDeltaC)) in balloon-denuded cholesterol-fed rabbit aorta. AdLacZ was used as a control. Transduced VEGF-D(DeltaNDeltaC) mRNA was detectable in the arterial wall with RT-PCR at 6, 14 and 28 days. Gene transfer efficiency as detected with X-gal staining 6 days after the AdLacZ transduction was 1.91 +/- 1.32% in intima. AdVEGF-D(DeltaNDeltaC) gene transfer led to 52% reduction in intima/media ratio (I/M) as compared to the AdLacZ controls at 14 days time point. At 6 days there were no differences in I/M, but the number of macrophages in the vessel wall was 85% lower in the AdVEGF-D(DeltaNDeltaC) group as compared to the controls. The therapeutic effect was no longer detectable 28 days after the gene transfer. The therapeutic effect of VEGF-D(DeltaNDeltaC) was nitric oxide (NO)-dependent as the feeding of NO synthase inhibitor, L-NAME, blocked the reduction in intimal thickening. It is concluded that AdVEGF-D(DeltaNDeltaC) gene transfer reduces intimal thickening and macrophage influx into the vessel wall in balloon-denuded rabbit aortas.

Periadventitial angiopoietin-1 gene transfer induces angiogenesis in rabbit carotid arteries

This study was performed to evaluate angiogenic responses of angiopoietin-1 (Ang1) in vivo after adenovirus-mediated gene transfer in the periadventitial space of the rabbit carotid arteries using a collar technique. Adenoviruses encoding LacZ and vascular endothelial growth factor (VEGF) receptor-1-Ig fusion protein (VEGF-R1-Ig) adenoviruses were used as controls. Increased neovessel formation was seen in adventitia of the Ang1 transduced arteries 7 days after the gene transfer. Neovessels in the Ang1 transduced arteries were large in size and well perfused. Ang1 binds to Tie2 (tyrosine kinase with immunoglobulin and epidermal growth factor homology domain) receptors, which were expressed in the endothelium of the neovessels. When VEGF-R1-Ig was used with Ang1, it resulted in a decrease in the number of neovessels, which implies that VEGF-A or some other VEGF-R1 ligand(s) play a crucial role in angiogenesis occurring in response to Ang1. There were no significant differences in the total number of capillaries in the adventitia of the VEGF-R1-Ig transduced arteries as compared to LacZ controls. Neointima formation was not increased in the Ang1 transduced arteries as compared to the controls. We conclude that in the periadventitial space Ang1 shows angiogenic activity and is a potentially useful factor for the induction of therapeutic vascular growth in vivo.

Localization of m2 muscarinic receptor protein in parvalbumin and calretinin containing cells of the adult rat entorhinal cortex using two complementary methods

We investigated parvalbumin (PV) and calretinin (CR) containing interneurons in the rat entorhinal cortex. RNA amplification following single cell dissection of immunohistochemically labeled cells from layers II to VI revealed that PV cells, in contrast to CR cells, express the m2 muscarinic receptor (M2AchR) protein. Double immunostaining to confirm the results of RNA amplification indicated that the majority of PV cells contain M2AchR protein, whereas only a small proportion of CR cells do. In contrast, a large number of layer I CR cells, which are mostly Cajal-Retzius cells, were positive for M2AchR. RNA amplification following dissection of these cells also revealed that they contain the M2AchR protein. These findings emphasize that there are significant differences in the expression of different proteins, even among similar neuronal types in the same brain region. This highlights the importance of accurately collecting single cells, and knowledge of anatomical details in molecular biological studies.

Gene therapy of atherosclerosis

Atherosclerosis and related diseases are the leading cause of death in Western world. The disease process begins with the formation of fatty streaks already during the first decade of life but does not manifest clinically until several decades later. Gene therapy is a potential new way to target multiple factors playing a role in the development and progression of atherosclerosis. A great number of genes involved in the development of atherosclerosis have been identified and have been tested both in vitro and in vivo as potential new targets for therapy. Pre-clinical experiments have shown the feasibility and safety of several gene therapy applications for the treatment of atherosclerosis and clinical trials have also provided evidence for the applicability of gene therapy for the treatment of cardiovascular diseases. In this review we discuss vectors and potential gene therapy approaches for intervention and therapy of atherosclerosis.