Vitreous humor and albumin augment the proliferation of cultured retinal precursor cells

Abstract

Intravitreal injection is an important delivery route for studies involving the transplantation of various types of precursor cells to the retina; however, the effect on these cells of exposure to the vitreous microenvironment has not been specifically investigated. Here vitreous humor was evaluated for the potential to influence the proliferation of rat retinal precursor cells in vitro. Cells were isolated at embryonic day 19 and plated in standard proliferation medium in the presence or absence of fluid expressed from porcine vitreous humor. Cellular proliferation at different concentrations of vitreous fluid supplementation was quantified by using a (3)H-thymidine incorporation assay. Active components of vitreous fluid were partially characterized by gel filtration chromatography (GFC) and UV spectral analysis. The effect of each vitreous fraction on proliferation was determined as well. Results showed that addition of 20% vitreous fluid to primary rat retinal cultures significantly increased (3)H-thymidine incorporation compared with growth medium without vitreous supplementation. A vitreous fraction showing growth-promoting activity was localized to a molecular mass range <1000 Da, consistent with ascorbic acid. Ascorbic acid was confirmed in vitreous fluid by UV spectral analysis. Growth-augmenting activity was present in higher molecular mass vitreous fractions, consistent with protein components. Albumin, the major protein in vitreous fluid, was found to augment proliferation. Because vitreous-associated augmentation of retinal precursor proliferation remains an epidermal growth factor-dependent phenomenon, the proliferative status of transplanted cells in the vitreous cavity is likely determined by a combination of factors.

Rejuvenation of three germ layers tissues by exchanging old blood plasma with saline-albumin

“…Interestingly, in contrast to the lack of effects on myogenic cells, ectopic albumin enhanced NPC proliferation by itself -in the absence of serum and improved NPC proliferation when old serum was present in the cultures (Supplementary Figure 3B). These results agree with previously published enhancement of proliferation of retinal precursor cells by albumin [29] and with efficient proliferation of human iPSC-derived NPCs on electrospun serum albumin fibrous scaffolds [30].…”

Therapeutic Potential of Anti-Angiogenic Multitarget N,O-Sulfated E. Coli K5 Polysaccharide in Diabetic Retinopathy

“…The assessment of the angiogenic potential of the PDR vitreous humor may provide a useful tool for a preclinical evaluation of therapeutic angiostatic molecules (6,(45)(46)(47). Here, PDR vitreous fluid elicits a potent angiogenic response in vitro and in vivo.…”

“…The evaluation of the angiogenic effects exerted by the vitreous humor obtained after pars plana vitrectomy may provide a useful tool for a preclinical screening of angiostatic molecules with potential implications for the therapy of PDR (6,(45)(46)(47). To this aim, preliminary experiments were performed to define the amount of PDR vitreous fluid that exerts an optimal angiogenic response in the HUVEC sprouting and chick embryo CAM assays.…”

Albumin and mammalian cell culture: implications for biotechnology applications

“…There are beneficial effects of albumin in cell culture resulting from its interactions with other biological factors such as insulin, epidermal growth factor (EGF) or as a carrier of the intracellular signalling molecule, nitric oxide (Ishima et al 2008). In retinal precursor cells albumin augmented their proliferation in association with EGF and this suggests the commercial cell line Per.C6™, derived from human embryonic retinal cells, may benefit from media containing a combination of these factors (Yang et al 2009). In the case of stem cells, cell-based tissue engineering, and mammalian cell produced protein therapeutics, the requirement for a recombinant form of human serum albumin may offer culture performance benefits, and certainly would address many of the regulatory concerns arising from the use of animal sourced medium components (Carpenter et al 2009).…”