Extracellular matrix protein coatings for facilitation of urothelial cell attachment

Bisphenol A Alters the Energy Metabolism of Stromal Cells and Could Promote Bladder Cancer Progression

Simple Summary

Our research brings new insight on the potential impact of bisphenol A on bladder cancer progression. By evaluating the effects of bisphenol A on the stromal environment of bladder cancer, we aimed to demonstrate that this endocrine disruptor could promote bladder cancer invasion through alteration of the energy metabolism of stromal cells, specifically on bladder fibroblasts and cancer-associated fibroblasts. These findings could modify the understanding of bladder cancer since bladder tissue is not recognized as a hormone-sensitive tissue. Consequently, our study suggests that endocrine disruptors, such as bisphenol A, could impact bladder cancer progression.

Abstract

Bisphenol A (BPA) is an endocrine-disrupting molecule used in plastics. Through its release in food and the environment, BPA can be found in humans and is mostly excreted in urine. The bladder is therefore continuously exposed to this compound. BPA can bind to multiple cell receptors involved in proliferation, migration and invasion pathways, and exposure to BPA is associated with cancer progression. Considering the physiological concentrations of BPA in urine, we tested the effect of nanomolar concentrations of BPA on the metabolism of bladder fibroblasts and cancer-associated fibroblasts (CAFs). Our results show that BPA led to a decreased metabolism in fibroblasts, which could alter the extracellular matrix. Furthermore, CAF induction triggered a metabolic switch, similar to the Warburg effect described in cancer cells. Additionally, we demonstrated that nanomolar concentrations of BPA could exacerbate this metabolic switch observed in CAFs via an increased glycolytic metabolism, leading to greater acidification of the extracellular environment. These findings suggest that chronic exposure to BPA could promote cancer progression through an alteration of the metabolism of stromal cells.

Structural and bone marrow stem cell biocompatibility studies of hydrogel synthesized via chemo-enzymatic route

Natural biopolymers have many attractive medical applications; however, complications due to fibrosis caused a reduction in diffusion and dispersal of nutrients and waste products. Consequently, severe immunocompatibility problems and poor mechanical and degradation properties in synthetic polymers ensue. Hence, the present study investigates a novel hydrogel material synthesized from caprolactone, ethylene glycol, ethylenediamine, polyethylene glycol, ammonium persulfate, and tetramethylethylenediamine via chemo-enzymatic route. Spectroscopic analyses indicated the formation of polyurea and polyhydroxyurethane as the primary building block of the hydrogel starting material. Biocompatibility studies showed positive observation in biosafety test using direct contact cytotoxicity assay in addition to active cellular growth on the hydrogel scaffold based on fluorescence observation. The synthesized hydrogel also exhibited (self)fluorescence properties under specific wavelength excitation. Hence, synthesized hydrogel could be a potential candidate for medical imaging as well as tissue engineering applications as a tissue expander, coating material, biosensor, and drug delivery system.

Dynamic reciprocity in cell-scaffold interactions

Tissue engineering in urology has shown considerable promise. However, there is still much to understand, particularly regarding the interactions between scaffolds and their host environment, how these interactions regulate regeneration and how they may be enhanced for optimal tissue repair. In this review, we discuss the concept of dynamic reciprocity as applied to tissue engineering, i.e. how bi-directional signaling between implanted scaffolds and host tissues such as the bladder drives the process of constructive remodeling to ensure successful graft integration and tissue repair. The impact of scaffold content and configuration, the contribution of endogenous and exogenous bioactive factors, the influence of the host immune response and the functional interaction with mechanical stimulation are all considered. In addition, the temporal relationships of host tissue ingrowth, bioactive factor mobilization, scaffold degradation and immune cell infiltration, as well as the reciprocal signaling between discrete cell types and scaffolds are discussed. Improved understanding of these aspects of tissue repair will identify opportunities for optimization of repair that could be exploited to enhance regenerative medicine strategies for urology in future studies.

Tissue engineering for human urethral reconstruction: systematic review of recent literature

BACKGROUND

Techniques to treat urethral stricture and hypospadias are restricted, as substitution of the unhealthy urethra with tissue from other origins (skin, bladder or buccal mucosa) has some limitations. Therefore, alternative sources of tissue for use in urethral reconstructions are considered, such as ex vivo engineered constructs.

PURPOSE

To review recent literature on tissue engineering for human urethral reconstruction.

METHODS

A search was made in the PubMed and Embase databases restricted to the last 25 years and the English language.

RESULTS

A total of 45 articles were selected describing the use of tissue engineering in urethral reconstruction. The results are discussed in four groups: autologous cell cultures, matrices/scaffolds, cell-seeded scaffolds, and clinical results of urethral reconstructions using these materials. Different progenitor cells were used, isolated from either urine or adipose tissue, but slightly better results were obtained with in vitro expansion of urothelial cells from bladder washings, tissue biopsies from the bladder (urothelium) or the oral cavity (buccal mucosa). Compared with a synthetic scaffold, a biological scaffold has the advantage of bioactive extracellular matrix proteins on its surface. When applied clinically, a non-seeded matrix only seems suited for use as an onlay graft. When a tubularized substitution is the aim, a cell-seeded construct seems more beneficial.

CONCLUSIONS

Considerable experience is available with tissue engineering of urethral tissue in vitro, produced with cells of different origin. Clinical and in vivo experiments show promising results.

The development of fibronectin-functionalised hydroxyapatite coatings to improve dermal fibroblast attachment in vitro

The success of long-term transcutaneous implants depends on dermal attachment to prevent downgrowth of the epithelium and infection. Hydroxyapatite (HA) coatings and fibronectin (Fn) have independently been shown to regulate fibroblast activity and improve attachment. In an attempt to enhance this phenomenon we adsorbed Fn onto HA-coated substrates. Our study was designed to test the hypothesis that adsorption of Fn onto HA produces a surface that will increase the attachment of dermal fibroblasts better than HA alone or titanium alloy controls.

Iodinated Fn was used to investigate the durability of the protein coating and a bioassay using human dermal fibroblasts was performed to assess the effects of the coating on cell attachment. Cell attachment data were compared with those for HA alone and titanium alloy controls at one, four and 24 hours. Protein attachment peaked within one hour of incubation and the maximum binding efficiency was achieved with an initial droplet of 1000 ng. We showed that after 24 hours one-fifth of the initial Fn coating remained on the substrates, and this resulted in a significant, three-, four-, and sevenfold increase in dermal fibroblast attachment strength compared to uncoated controls at one, four and 24 hours, respectively.

Surface modification of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer films for promoting interaction with bladder urothelial cells

Often bladder dysfunction and diseases lead to therapeutic interventions that require partial or complete replacement of damaged tissue. For this reason, the development of biomaterials to repair the bladder by promoting the adhesion and growth of urothelial cells is of interest. With this aim, a modified copolyester of biocompatible and biodegradable poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(HB-co-HV)] was used as scaffold for porcine urothelial cell culture. In addition to good biocompatibility, the surface of P(HB-co-HV) substrates was modified to provide both, higher hydrophilicity and a better interaction with urothelial cells. Chemical treatments with ethylenediamine (ED) and sodium hydroxide (NaOH) led to substrate surfaces with decreasing hydrophobicity and provided functional groups that enable the grafting of bioactive molecules, such as a laminin derived YIGSR sequence. Physico-chemical properties of modified substrates were studied and compared with those of the pristine P(HB-co-HV). Urothelial cell morphology on treated substrates was studied. The results showed that focal attachment and cell-related properties were improved for peptide grafted polymer compared with both, the unmodified and functionalized copolyester.

Nanostructured bladder tissue replacements

The interaction between cells or tissues and natural or synthetic materials which mimic the natural biological environment has been a matter of great interest in tissue engineering. In particular, surface properties of biomaterials (regardless of whether they are natural or synthetic) have been optimized using nanotechnology to improve interactions with cells for regenerative medicine applications. Specifically, in vivo and in vitro studies have demonstrated greater bladder tissue growth on polymeric surfaces with nanoscale to submicron surface features. Improved bladder cell responses on nanostructured polymers have been correlated to unique nanomaterial surface features leading to greater surface energy which influences initial protein interactions. Moreover, coupled with the observed greater in vitro and in vivo bladder cell adhesion as well as proliferation on nanostructured compared to conventional synthetic polymers, decreased calcium stone formation has also been measured. In this article, the importance of nanostructured biomaterial surface features for bladder tissue replacements are reviewed with thoughts on future directions for this emerging field.