Objective Lymphatic vessels collect extravasated fluid and proteins from tissues to blood circulation as well as play an essential role in lipid metabolism by taking up intestinal chylomicrons. Previous studies have shown that impairment of lymphatic vessel function causes lymphedema and fat accumulation, but clear connections between arterial pathologies and lymphatic vessels have not been described. Approach and Results Two transgenic mouse strains with lymphatic insufficiency (sVEGFR3 and Chy) were crossed with atherosclerotic mice (LDLR−/−/ApoB100/100) to study the effects of insufficient lymphatic vessel transport on lipoprotein metabolism and atherosclerosis. Both sVEGFR3 × LDLR−/−/ApoB100/100 mice and Chy × LDLR−/−/ApoB100/100 mice had higher plasma cholesterol levels compared to LDLR−/−/ApoB100/100 control mice during both normal chow diet (16.3 mmol/l and 13.7 mmol/l vs. 8.2 mmol/l, respectively) and Western-type high fat diet (e.g. after 2 weeks of fat diet 45.9 mmol/l and 42.6 mmol/l vs. 30.2 mmol/l, respectively). Cholesterol and triglyceride levels in very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) fractions were increased. Atherosclerotic lesions in young and intermediate cohorts of sVEGFR3 × LDLR−/−/ApoB100/100 mice progressed faster than in control mice (e.g. intermediate cohort mice at 6 weeks 18.3% vs. 7.7% of the whole aorta, respectively). In addition, lesions in sVEGFR3 × LDLR−/−/ApoB100/100 mice and Chy × LDLR−/−/ApoB100/100 mice had much less lymphatic vessels than lesions in control mice (0.33% and 1.07% vs. 7.45% of podoplanin positive vessels, respectively). Conclusions We show a novel finding linking impaired lymphatic vessels to lipoprotein metabolism, increased plasma cholesterol levels and enhanced atherogenesis.

Therapeutic monoclonal antibodies (mAbs) are the fastest growing class of new therapeutic molecules. They hold great promises for the treatment of a variety of diseases, including chronic inflammatory diseases and cancer. However, the current manufacturing and purification processes cause limitations in the production capacity of therapeutic antibodies, leading to an increase in cost. Genetic delivery of therapeutic monoclonal antibodies by in vivo production offers a new potential solution to these problems. Firstly, therapeutic efficacy can be improved by maintaining stable therapeutic, non-toxic levels within the blood circulation over a long period of time. Repeated high-dose bolus injections could be avoided, thereby reducing the possibility of side-effects. Secondly, the high cost of manufacturing and purification of the therapeutic antibodies could be reduced, making an in vivo/ex vivo mAb gene transfer an economically viable and attractive option. In general, three approaches can be used for the stable long-term expression and secretion of therapeutic antibodies in vivo: 1) direct in vivo administration of integrating vectors carrying a mAb gene, 2) grafting of ex vivo genetically modified autologous cells, and 3) implantation of an encapsulated antibody producing heterologous or autologous cells. This paper describes the key factors and problems associated with the current antibody-based immunotherapies and reviews prospects for genetic in vivo delivery of therapeutic antibodies.

The therapeutic efficacy of a lentiviral vector (LV) expressing the herpes simplex virus thymidine kinase (HSV-TK) was studied in an immunocompetent rat glioblastoma model. Intraperitoneal ganciclovir injections (50 mg/kg/day) were administered for 14 consecutive days, resulting in reduced tumor volumes as monitored by MRI. Survival analyses revealed a significant improvement among the LV-expressing HSV-TK (LV-TK)/ganciclovir-treated animals when compared to non-treated control rats. However, a limiting factor in the use of LV has been the suboptimal small-scale production in flasks. Our aim during the translation phase, prior to entering the final pre-clinical and early clinical phases, was to develop a scalable, robust, and disposable manufacturing process for LV-TKs. We also aimed to minimize future process changes and enable production upscaling to make the process suitable for larger patient populations. The upstream process relies on fixed-bed iCELLis technology and transient plasmid transfection. This is the first time iCELLis 500 commercial-scale bioreactor was used for LV production. A testing strategy to determine the pharmacological activity of LV-TK drug product by measuring cell viability was developed, and the specificity of the potency assay was also proven. In this paper we focus on upstream process development while showing analytical development and the proof-of-concept of LV-TK functionality.