Attachment and growth of fibroblast cells on polypeptide derivatives

In Vivo and In Vitro Fibroblasts' Behavior and Capsular Formation in Correlation with Smooth and Textured Silicone Surfaces

BACKGROUND

As the most principal complication following breast augmentation with silicone breast implants, capsular contracture is greatly influenced by surface texture. However, there have long been widespread debates on the function of smooth or textured surface implants in reducing capsular contracture.

MATERIALS AND METHODS

Three commercially available silicone breast implants with smooth and textured surfaces were subjected to surface characterization, and in vitro and in vivo assessments were then implemented to investigate the effect of these different surfaces on the biological behaviors of fibroblasts and capsular formation in rat models.

RESULTS

Surface characterization demonstrated that all three samples were hydrophobic with distinct roughness values. Comparing the interactions of fibroblasts or tissues with different surfaces, we observed that as surface roughness increased, the adhesion and cell spreading of fibroblasts, the level of echogenicity, the density of collagen and α-SMA-positive immunoreactivity decreased, while the proliferation of fibroblasts and capsule thickness increased.

CONCLUSIONS

Our findings elucidated that the effect of silicone implant surface texture on fibroblasts' behaviors and capsular formation was associated with variations in surface roughness, and the number of myofibroblasts may have a more significant influence on the process of contracture than capsule thickness in the early stage of capsular formation. These results highlight that targeting myofibroblasts may be wielded in the prevention and treatment strategies of capsular contracture clinically.

LEVEL OF EVIDENCE V

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Cell Growth on Immobilized Cell-Growth Factor. Interactions of Fibroblast Cells with Insulin Immobilized on 2-Hydroxyethyl Methacrylate /Ethyl Methacrylate Copolymer Membranes

The adhesion and growth of mouse fibroblast cells STO were in vestigated in the presence of 2-hydroxyethyl methacrylate/ethyl methacrylate copolymer membranes with immobilized insulin. For the copolymer membrane without immobilized insulin, cell adhesion and growth were moderately sup pressed, on those copolymer membranes containing very high or very low 2-hydroxyethyl methacrylate content. A similar effect by the copolymer compo sition was observed on the membranes immobilized with small amounts of in sulin. Large amounts of immobilized insulin remarkably enhanced cell growth and masked the copolymer composition effects. The immobilized insulin en hanced the cell growth more than free insulin.

Co-culture of hepatocytes and fibroblasts by micropatterned immobilization of beta-galactose derivatives

Photosensitive poly(allylamine) containing beta-galactose moieties in the side chain (LPAN(3)) was prepared by the reaction of poly(allylamine) with lactobionic acid and azidobenzoic acid. To create micropatterned surfaces, a LPAN(3)-coated poly(methyl methacrylate) (PMMA) substrate was irradiated with an ultraviolet lamp under a photomask. The presence of a LPAN(3) layer on the substrate was confirmed using an electron spectroscopy for chemical analysis. Micropatterned cell culture was carried out by seeding hepatocytes and/or fibroblasts on the substrate. As a result, hepatocytes and fibroblasts adhered only to the LPAN(3) and PMMA lane, respectively. Co-culture on the stripe patterned substrate was carried out by the first cell seeding of hepatocytes and subsequently by the second cell seeding of fibroblasts. The co-cultured cells produced extracellular matrix such as fibronectin, suggesting a biological function.

Structure-property correlations in a combinatorial library of degradable biomaterials

A combinatorial library of degradable polyarylates was prepared. These polymers are A-B-type copolymers consisting of an alternating sequence of a diphenol and a diacid. The library was prepared by copolymerizing, in all possible combinations, 14 different tyrosine-derived diphenols and eight different aliphatic diacids, resulting in 8 x 14 = 112 distinct polymers. This approach (a) increases the number of available polymeric candidate materials for medical applications, and (b) facilitates the identification of correlations between polymer structure and glass transition temperature, air-water contact angle, mechanical properties, and fibroblast proliferation. The pendent chain and backbone structures were systematically varied by (a) simple homologative variations in the number of methylene groups, (b) substitution of oxygen for methylene groups, and (c) introduction of branched and aromatic structures. The polymers contained within the library exhibited incremental variations in Tg (from 2 degrees C to 91 degrees C) and air-water contact angle (from 64 degrees to 101 degrees ). Fibroblast proliferation (in vitro, serum-containing media) ranged from approximating that measured on tissue culture polystyrene to complete absence of proliferation. Generally, decreased proliferation correlated linearly with increased surface hydrophobicity, except in those polymers derived from oxygen-containing diacids in their backbone which were uniformly good growth substrates even if their surfaces were very hydrophobic. In a selected subgroup of polymers, tensile strength of thin solvent cast films ranged from about 6 to 45 MPa, while Young's modulus (stiffness) ranged from about 0.3 to 1.7 GPa. Combinatorial biomaterial libraries such as these tyrosine-derived polyarylates permit the systematic study of material-dependent biological responses and provide the medical device designer with the option to choose a suitable material from a library of related polymers that encompasses a broad range of properties.

Cultivation of fibroblast cells on keratin-coated substrata

By means of a cell culture method, the attachment and growth of mouse L929 fibroblast cells were studied on matrices of the (-SDS)- and (+SDS)-keratins, which were extracted from wool in the absence and presence of sodium dodecyl sulfate, respectively. The (+SDS)-keratin showed some toxic effect on the cell growth, but upon washing with a pH 7/phosphate buffer, the protein behaved similarly to a substratum of the (-SDS)-keratin. The comparative culture assay on the keratins, collagen (type I), and glass revealed that the keratins were more adhesive to the cells and more supportive for cell proliferation than the collagen and glass. The results were explained by an enhanced initial adsorption of mediator proteins from fetal bovine serum onto the keratin substrata.

Study of blood compatible polymers. III. Copolymers of N-benzyl, N-(2-hydroxyethyl) acrylamide and 2-hydroxyethyl methacrylate

Copolymerization of 2-hydroxyethyl methacrylate (HEMA) and N-benzyl, N-(2-hydroxyethyl) acrylamide (BENAAm) was carried out at different mole ratios of the monomers to obtain copolymers of varying composition. BENAAm content of the copolymers varies between 13 and 70%. Investigation of the interaction of rabbit platelets with these polymer surfaces showed that copolymers with higher BENAAm content inhibit the platelet deformation. Human umbilical cord fibroblast cells proliferated very well on the copolymer surfaces. The cell growth rate on polyHEMA was relatively low. Maximum cell growth was observed on the copolymer having 87% HEMA.

Materials for enhancing cell adhesion by immobilization of cell-adhesive peptide

Materials to enhance cell adhesion were synthesized by surface integration of peptide, Arg-Gly-Asp-Ser(RGDS), which is an active-site sequence of cell-adhesive proteins. Polystyrene film was glow-discharged and graft-copolymerized with acrylic acid. Then the peptide was immobilized to the poly(acrylic acid) grafts by using water-soluble carbodiimide. The cell-adhesive activity of the RGDS-immobilized film increased with increasing amount of immobilized peptide, and approached the activity of fibronectin(FN)-immobilized film. The RGDS-immobilized film was more stable against heat treatment and pH variation than the FN-immobilized film. In addition, the RGDS-immobilized film enhanced cell growth more strongly than the FN-immobilized film.

In vitro bone formation on coral granules

We investigated the ability of fetal rat bone cells isolated after collagenase digestion to differentiate in vitro and to produce a mineralized matrix on coral granules. Scanning electron microscopy examination of the surface of the seeded coral granules revealed that cells attached, spread, and proliferated on the material surface. Bone nodule formation was studied in this in vitro system by direct examination under an inverted phase contrast microscope. The initial event observed was the appearance of cells with phosphatase alkaline activity arranged in several layers and forming a three-dimensional organization around the coral particles. By Day 7, nodule formation began and a refringent material appeared and extended to the background cells during the following days. By Day 15, some coral granules were embedded in a mineralized matrix. Histologic results demonstrated the formation of a mineralized tissue with the appearance of woven bone.

Platelet adhesion on to polyamide microcapsules coated with lipid bilayer membrane

Polyamide microcapsules with diameters of 3-4 microns were coated with lipid bilayer membrane and their interaction with canine platelets was investigated. Platelet adhesion on to the microcapsules was significantly suppressed by the lipid-coating. Coating with dimyristoylphosphatidylcholine (liquid-crystalline state) reduced platelet adhesion on to the microcapsules to a greater extent than that with dipalmitoylphosphatidylcholine (gel state) at 37 degrees C. The surface properties of the microcapsule in adsorption of plasma proteins were also changed by lipid coating. The amount of gamma-globulin and fibrinogen adsorbed on to the microcapsule was slightly decreased by lipid coating, while the amount of adsorbed albumin was increased. Platelet adhesion on to the lipid-coated microcapsules was suppressed most strongly in the presence of gamma-globulin. Apparently platelet adhesion on to the polyamide microcapsules is controlled by the nature of lipid membrane and gamma-globulin adsorbed on to the microcapsules.