Evaluation of angiogenic inhibitors with an in vivo quantitative angiogenesis method using agarose microencapsulation and mouse hemoglobin enzyme-linked immunosorbent assay

An understanding of potential and limitations of alginate/PLL microcapsules as a cell retention system for perfusion cultures

Microcapsules for high cell density culture of mammalian cells have found an increasing interest, however, the poor stability of the microcapsules and the lack of characterisation methods led to few quantitative results. Alginate-poly-L-lysine (PLL) microcapsules have been studied in detail in order to form a basis for comparison of capsules made from different polymers. Since the microcapsules can be easily retained in the bioreactor without the need for a cell separation device, high cell densities were achieved with a maximum of 4 × 10(7) cell/ml(microcapsules), corresponding to a colonisation of 5% of the internal capsule volume. Measurement of microcapsule integrity and mechanical resistance showed that alginate-PLL microcapsules are not suitable for perfusion cultures since they are very sensitive to media composition, mainly the presence of non-gelling ions that have a higher affinity for alginate than PLL and Ca(2+), leading to the leakage of PLL and Ca(2+), and to microcapsule rupture.

Protection of mammalian cell used in biosensors by coating with a polyelectrolyte shell

In order to detect xenoestrogens which induce perturbations of mammalian cells, design of biosensor using a mammalian cell line enable to detect these compounds is necessary. MELN cell line is suitable to detect estrogen activity, since they are stably transfect with an estrogen regulated luciferase gene. To realize this biosensor, it appeared necessary to add a protection to the mamalian cell, which is devoided, of the wall protecting yeasts or plant cells. With this aim in view, MELN cells have been isolated with a polyelectrolyte shell using the layer-by-layer technique. Among several polyelectrolyte-couples, the best cell survival (>80%) was obtained by alternating the polycation poly-diallyldimethyl ammonium chloride layer and the negatively charged poly-styrene sulfonate. We observed that the composition of the buffer used for layer-deposition was crucial to preserving cell viability, e.g. potassium ions were preferred to sodium ions during the coating. Furthermore, viability was increased when cells were allowed to recover for 2 h between each bilayer deposition. The use of engineered mammalian cells that synthesize luciferase as a response to exposure to estradiol, demonstrated that coating not only permits cell survival, but also allows essential metabolic functions, such as RNA and protein synthesis to take place. Capsule formation allows free diffusion of small molecules, while it prevents internalization in the cells of proteins larger than 60 kDa.

Intravitreal triamcinolone with transpupillary therapy for subfoveal choroidal neovascularization in age related macular degeneration. A randomized controlled pilot study [ISRCTN74123635]

BACKGROUND

To assess the effect of intravitreal triamcinolone acetonide (iTA) as an adjunctive treatment to transpupillary therapy (TTT) for new subfoveal choroidal neovascular membranes (CNV) in age-related macular degeneration (AMD).

METHODS

This prospective randomized controlled pilot study comprised 26 patients scheduled to receive TTT, due to either absent indications for photodynamic therapy or financial issues. Patients were assigned into; Group A (n = 14) received TTT alone and Group B (n = 12) received iTA (4 mg) followed by TTT within one week. Follow ups were at 2 weeks, and 1, 3 and 6 months for; best-corrected visual acuity (BCVA) by ETDRS chart at 4 meters, intraocular pressures (IOP), fluorescein angiography (FAG), and central foveal thickness by optical coherence tomography (OCT).

RESULTS

All 26 patients completed 6 months of follow ups. The average age for both groups was 74 years. Occult CNV formed 64% and 41%; classis/predominately classic 21% and 16.6%; and minimally classic 15% and 42.4% of group A and B respectively. At baseline; the mean BCVA was 0.045 for group A and 0.04 for group B; mean CNV size was 6.15 disc diameter (DD) and 2.44 DD; mean OCT foveal thickness was 513 um and 411 um for group A and B respectively with no statistical differences (P = 0.8, 0.07, and 0.19). At six months the proportion of patients gained > or = 1 lines was 14% and 25% (P = 0.136) and stabilization was 86% and 66% (P = 0.336); the mean size of the CNV was 5.63 DD and 2.67 DD (P = 0.162); rate of CNV closure was 64% and 83% (P = 0.275); and the mean OCT central foveal thickness was 516.36 um and 453.67 um (P = 0.341), for group A and B respectively.

CONCLUSION

The use of iTA as an adjunctive to TTT for new subfoveal CNV in AMD showed a tendency towards better functional results. However due to the small sample size of the study a statistically significant results could not be reached.

[DDS and Me]

With the success of the human genome project, the focus of life science research has shifted to the functional and structural analyses of proteins, such as proteomics and structural genomics. These analyses of proteins including newly identified proteins are expected to contribute to the identification of therapeutically applicable proteins for various diseases. Thus, pharmaco-proteomic-based drug discovery and development for protein therapies, including gene therapy, cell therapy, and vaccine therapy, is attracting current attention. However, there is clinical difficulty in using almost all bioactive proteins, because of their very low stability and pleiotropic actions in vivo. To promote pharmaco-proteomic-based drug discovery and development, we have attempted to develop drug delivery systems (DDSs), such as the protein-drug innovation system and the optimal cell therapeutic system. In this review, we introduce our original DDSs.

Combined photodynamic therapy with verteporfin and intravitreal triamcinolone acetonide for choroidal neovascularization

PURPOSE

To examine combined photodynamic therapy (PDT) with verteporfin and intravitreal triamcinolone acetonide for choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD).

DESIGN

Noncomparative case series.

PARTICIPANTS

Twenty-six eyes of 26 patients with CNV secondary to AMD. Thirteen with CNV, without restriction to type, were not treated with prior PDT and were called the Newly Treated group. Thirteen patients with prior PDT therapy who experienced visual loss during treatment with PDT alone comprised the remainder and were termed the Prior PDT group.

METHODS

Patients with CNV were treated with PDT immediately followed by an intravitreal injection of 4 mg of triamcinolone acetonide. Visual acuity was measured by Early Treatment Diabetic Retinopathy Study protocol refraction. Need for retreatment was based on fluorescein angiographic evidence of leakage at 3-month follow-up intervals.

MAIN OUTCOME MEASURES

Visual acuity and retreatment rate.

RESULTS

Of the 13 patients in the Newly Treated group the mean visual acuity change at 3 months was an improvement of 1.9 lines, and 4 (30.8%) had an improvement of at least 3 lines. Two patients (15.4%) required retreatment at 3 months. At the 6-month follow-up, available for 12 patients in the Newly Treated group, the mean visual acuity change from baseline was an improvement of 2.4 lines, 4 patients (33%) had an improvement of at least 3 lines and 1 patient required retreatment. At both time points the visual acuity was significantly greater than at baseline (P = 0.023 and P = 0.007, at the 3-month and 6-month time points, Wilcoxon signed ranks test) for patients in the Newly Treated group. Among the 13 patients in the Prior PDT group, the mean change in visual acuity from baseline at the 3-month follow-up was 0.31 lines and 1 patient (7.7%) had an improvement of at least 3 lines. Six-month follow-up was available for 11 patients in the Prior PDT group and the mean change from baseline visual acuity was 0.1 lines and 1 patient (9.1%) experienced an improvement of 3 or more lines. No patient in the Prior PDT group required retreatment at 3 or 6 months. At the 3-month and 6-month time points the visual acuity was not significantly different than the baseline acuity in the Prior PDT group. No patient in either group at any time point experienced a loss of visual acuity of 3 or more lines. Five patients (19.2%), 3 in the Newly Treated group and 2 in the Prior PDT group, required monodrop therapy to control their intraocular pressure. No patient developed endophthalmitis.

CONCLUSION

Although the number of patients in this pilot study was limited, the improvement of acuity and the lack of fluorescein leakage in these patients suggest combination therapy with PDT and intravitreal triamcinolone acetonide, particularly when used as first-line therapy, merits further investigation.

Vascularization pattern of C6 glioma is modified with medroxyprogesterone acetate and ibuprofen in Wistar rat brain

Beneficial effects of medroxyprogesterone acetate (MPA) in cancer therapy is partly mediated via its antiangiogenic activity. The same is true for the antitumoral action of non-steroidal antiinflammatory drugs. We have studied two liposoluble drugs, MPA and the analgesic ibuprofen, on glioma vascularization in vivo. In this study we have shown that, until the sacrifice at 27. day after tumor inoculation in the right hemisphere, MPA had a slight though insignificant activity to reduce the fatality of C6 glioma, growing in right cerebral hemisphere of male Wistar rats. But ibuprofen both alone or with MPA had no effect on survival with gavage application of a 30 mg/kg/day dosing regime. On histological analysis, intra- and peritumoral vessels were counted. Progesterone seemed to lower intratumoral, but to increase peritumoral vessels, especially glomeruloids, around the tumor mass. Coadministration of ibuprofen acted to suppress the peritumoral vessel increase, and to enhance lymphomonocytic infiltration around tumor vessels.

Matrilysin stimulates DNA synthesis of cultured vascular endothelial cells and induces angiogenesis in vivo

Matrilysin produced by human colon cancer cells may be involved in the progression and metastasis of cancer. In the present study, we investigated the association of matrilysin with angiogenesis. One microgram of recombinant matrilysin is confirmed to have increased [3H]-thymidine uptake in human umbilical vein endothelial cells. Then we used micro encapsulation and a mouse hemoglobin enzyme-linked immunosorbent assay system for in vivo quantitation of angiogenesis with BALB/c nu/nu athymic mice. Hundred micrograms of recombinant matrilysin induced angiogenesis to the same degree as 10 microg of basic fibroblast growth factor (bFGF). Angiogenesis was observed at the site implanted with human colon cancer WiDr cells in agarose micro beads. This was inhibited by subcutaneous injection of matrilysin-specific antisense oligonucleotide significantly by 53%. In conclusion, matrilysin may be associated with angiogenesis of human colon cancer through the direct proliferative action on endothelial cells.

Treatment of murine angiosarcoma with etoposide, TNP-470 and prednisolone

To develop effective therapies for angiosarcoma, we investigated the anti-tumor effects of etoposide (ETO), TNP-470 and prednisolone (PSL) using an established murine angiosarcoma cell line (ISOS-1). We examined the direct anti-tumor and anti-angiogenic effects of these drugs on ISOS-1 cells and normal murine microvascular endothelial cells (mECs) in vitro. Cell growth of ISOS-1 was inhibited significantly by ETO, moderately by TNP-470, and not at all by PSL (IC(50): 0.25 microg/ml, 10 microg/ml, >8000 microg/ml, respectively). One the other hand, cell growth of mECs was inhibited significantly by TNP-470, slightly by PSL, and negligibly by ETO (IC(50): 0.85 ng/ml, 0.7 microg/ml, 10 microg/ml, respectively). In an in vivo assay, tumor growth of ISOS-1 was significantly inhibited by more than 2.5 mg/kg of ETO dose-dependently, and by more than 30 mg/kg of TNP-470, and 100 mg/kg of PSL individually. Combination treatments of ETO+TNP-470 and TNP-470+PSL showed synergistic enhancement of inhibition (% control inhibition: ETO vs. TNP-470 vs. ETO+TNP-470: 55 versus 55 vs. 16%) (% control inhibition: TNP-470 vs. PSL vs. TNP-470+PSL: 41 vs. 86 vs. 21%). ETO+PSL combination treatment, however, failed to show significant enhancement of anti-tumor effects. In conclusion, our results indicated that TNP-470 may be a very effective drug for angiosarcoma treatment, especially in combination with ETO or PSL. We eagerly anticipate the use of TNP-470 in clinical treatment of angiosarcoma.

Technology of mammalian cell encapsulation

Entrapment of mammalian cells in physical membranes has been practiced since the early 1950s when it was originally introduced as a basic research tool. The method has since been developed based on the promise of its therapeutic usefulness in tissue transplantation. Encapsulation physically isolates a cell mass from an outside environment and aims to maintain normal cellular physiology within a desired permeability barrier. Numerous encapsulation techniques have been developed over the years. These techniques are generally classified as microencapsulation (involving small spherical vehicles and conformally coated tissues) and macroencapsulation (involving larger flat-sheet and hollow-fiber membranes). This review is intended to summarize techniques of cell encapsulation as well as methods for evaluating the performance of encapsulated cells. The techniques reviewed include microencapsulation with polyelectrolyte complexation emphasizing alginate-polylysine capsules, thermoreversible gelation with agarose as a prototype system, interfacial precipitation and interfacial polymerization, as well as the technology of flat sheet and hollow fiber-based macroencapsulation. Four aspects of encapsulated cells that are critical for the success of the technology, namely the capsule permeability, mechanical properties, immune protection and biocompatibility, have been singled out and methods to evaluate these properties were summarized. Finally, speculations regarding future directions of cell encapsulation research and device development are included from the authors' perspective.