Induction of Angiogenesis by Matrigel Coating of VEGF-Loaded PEG/PCL-Based Hydrogel Scaffolds for hBMSC Transplantation

hBMSCs are multipotent cells that are useful for tissue regeneration to treat degenerative diseases and others for their differentiation ability into chondrocytes, osteoblasts, adipocytes, hepatocytes and neuronal cells. In this study, biodegradable elastic hydrogels consisting of hydrophilic poly(ethylene glycol) (PEG) and hydrophobic poly(ε-caprolactone) (PCL) scaffolds were evaluated for tissue engineering because of its biocompatibility and the ability to control the release of bioactive peptides. The primary cultured cells from human bone marrow are confirmed as hBMSC by immunohistochemical analysis. Mesenchymal stem cell markers (collagen type I, fibronectin, CD54, integrin1β, and Hu protein) were shown to be positive, while hematopoietic stem cell markers (CD14 and CD45) were shown to be negative. Three different hydrogel scaffolds with different block compositions (PEG:PCL=6:14 and 14:6 by weight) were fabricated using the salt leaching method. The hBMSCs were expanded, seeded on the scaffolds, and cultured up to 8 days under static conditions in Iscove's Modified Dulbecco's Media (IMDM). The growth of MSCs cultured on the hydrogel with PEG/PCL= 6/14 was faster than that of the others. In addition, the morphology of MSCs seemed to be normal and no cytotoxicity was found. The coating of the vascular endothelial growth factor (VEGF) containing scaffold with Matrigel slowed down the release of VEGF in vitro and promoted the angiogenesis when transplanted into BALB/c nude mice. These results suggest that hBMSCs can be supported by a biode gradable hydrogel scaffold for effective cell growth, and enhance the angiogenesis by Matrigel coating.

Exacerbation of retinal degeneration and choroidal neovascularization induced by subretinal injection of Matrigel in CCL2/MCP-1-deficient mice

This study presents a mouse model for human age-related macular degeneration (AMD) as characterized by subretinal deposit and choroidal neovascularization. Matrigel, a basement membrane extract, solidifies after implantation in tissue and can stimulate local angiogenesis. This study demonstrates the induction of neovascularization and focal retinal degeneration following subretinal Matrigel injection in mice. In senescent mice, the normal functioning of CC chemokine CCL2/MCP-1 and its receptor CCR2 confers protection against age-related retinal degeneration, a disease that shares many similar features with human AMD. Our data shows that CCL2-deficient mice develop more severe disease as compared to the wild-type controls. These findings suggest that Matrigel subretinal injection could be used to generate AMD-like pathological changes. The data support the previously proposed role of CCL2 in AMD pathogenesis.

Angiocidal effect of Cyclosporin A: a new therapeutic approach for pathogenic angiogenesis

AIM

Angiogenesis is essential in the development of several disorders such as cancer, arthritis, and autoimmune diseases. Several agents prevent angiogenesis but only a few destroy established angiogenesis. In this study we tested whether local or systemic administration of Cyclosporin A (CyA) would inhibit as well as destroy established angiogenesis in an in vivo assay of angiogenesis.

METHODS

We utilized an in vivo assay of angiogenesis in which an angiogenic mixture of Matrigel, FGF, VEGF, and heparin was injected subcutaneously into mice. Angiogenesis in the subcutaneous plugs was quantified by ANOVA. CyA or the vehicle for CyA was administered to the experimental or the control groups by three routes: by addition to the angiogenic mixture, by local injection into the angiogenic plug at various time points or by systemic administration at high doses. Angiogenesis was quantified by pointing method and expressed as an angiogenic index (AI).

RESULTS

In control animals the subcutaneous plug of Matrigel with the angiogenic mixture revealed exuberant angiogenesis at day 4 and day 7. This angiogenesis was completely inhibited when CyA was included in the angiogenic mixture; the vehicle for CyA had no such effect. Angiogenesis that had progressed was found to regress after local subcutaneous injection of CyA at day 4 and 7. Similar regression of angiogenesis was noted when CyA was administered systemically after allowing angiogenesis to proceed for 4 days.

CONCLUSIONS

Our experiments strongly suggest that CyA is both angiocidal and angiostatic in vivo. These results provide a basis for future therapy directed against established angiogenesis in malignancies and autoimmune diseases.

Laminin-induced autoimmune myositis in rats

The present study aimed to examine if immunization with laminin causes myositis in rats and whether the pathologic findings mirror human polymyositis and dermatomyositis. Rats were immunized with an emulsion of laminin and complete Freund's adjuvant. As a result, muscle fiber necrosis with infiltrating macrophages was frequently observed and mononuclear cells were observed in the endomysium. These mononuclear cells were composed of CD4+ cells, CD8+ T cells, and macrophages. CD4+ cells and CD8+ T cells were mainly located in the endomysium, whereas a large number of macrophages were located in the endomysium and infiltrating muscle fibers. A small number of B cells, detected by immunohistochemical staining, were mainly located in the perimysium. The nonnecrotic muscle fiber to which CD4+ T cells, CD8+ T cells, and perforin+ cells adhered was negative for antimerosin and antidystrophin antibodies. Muscle fiber necrosis in rats immunized with laminin may occur after denaturation of basement membrane proteins. In conclusion, the immunization with laminin induces moderate to severe myositis. We suggest that laminin may be an important antigen for connective tissue diseases such as polymyositis and dermatomyositis.

New human oral squamous carcinoma cell line and its tumorigenic subline producing granulocyte colony-stimulating factor

A new human carcinoma cell line, MISK81-5, was established from a metastatic lymph node of oral squamous cell carcinoma. Immunocytochemical and ultrastructural observations revealed an obvious epithelial origin of the cell line. Chromosome analysis revealed a hypertriploid karyotype with numerical and structural anomalies. MISK81-5 cells could form a tumor mass in the subcutaneous tissue of recipient BALB/c athymic mice only when coinjected with Matrigel. A stem cell assay revealed that conditioned medium (CM) of MISK81-5 contained granulocyte colony-stimulating factor (G-CSF) or interleukin-6 activity. Quantitation by ELISA disclosed a higher concentration of G-CSF in the CM of MISK81-5 than in the CM of other squamous and gastric carcinoma cell lines. The sMISK, that was derived from MISK81-5 as a subpopulation of the cell line having higher tumorigenicity, also showed a similar hematopoietic stimulating activity to that of MISK81-5. These characteristics of the MISK81-5 cell line and its subpopulation, sMISK will be useful for studying the biological behavior of oral squamous cell carcinomas and its relation to hematopoietic stimulating factors.

Stimulation of angiogenesis as an explanation of Matrigel-enhanced tumorigenicity

Matrigel, a reconstituted extract of basement membrane, enhances the growth of different human cancer cell lines when transplanted into nude mice. Here that stimulation was confirmed in the BALB/c murine mammary-tumor cell line M3MC, as well as in human colon (SW948) and mammary (MDA-MB-468) carcinoma cell lines transplanted in nude and SCID mice, respectively. Subcutaneous and intra-mammary fat-pad inoculations of Matrigel alone generated an angiogenic response which was macroscopically evident by day 9. Histological analysis of the local host reaction occurring at the site of injection revealed an early peripheral fibroblast response, followed by mononuclear cell infiltration, solid and hollow fibroblast cords projections from the edge to the center of the Matrigel plug, and finally capillary ingrowths. Conditioned media obtained from the gels generated in vivo, acted as very strong chemoattractants for mouse lung capillary endothelial cells, stimulating their motility between 38 and 82 times with respect to the control. Our results suggest an important role of host cells recruited by Matrigel, which could favor angiogenesis of the area and thus facilitate the growth of tumor cells co-inoculated with the basement membrane extract.