In vitro models最新文献

Peripheral nerve injuries represent a major clinical challenge, if nerve ends retract, there is no spontaneous regeneration, and grafts are required to proximate the nerve ends and give continuity to the nerve. The nerve guidance conduits (NGCs) presented in this work are silk fibroin (SF)-based, which is biocompatible and very versatile. The formation of conduits is obtained by forming a covalently cross-linked hydrogel in two concentric moulds, and the inner longitudinally aligned pattern of the SF NGCs is obtained through the use of a patterned inner mould. SF NGCs with two wall thicknesses of ~ 200 to ~ 400 μm are synthesized. Their physicochemical and mechanical characteristics have shown improved properties when the wall thickness is thicker such as resistance to kinking, which is of special importance as conduits might also be used to substitute nerves in flexible body parts. The Young modulus is higher for conduits with inner pattern, and none of the conduits has shown any salt deposition in presence of simulated body fluid, meaning they do not calcify; thus, the regeneration does not get impaired when conduits have contact with body fluids. In vitro studies demonstrated the biocompatibility of the SF NGCs; proliferation is enhanced when iSCs are cultured on top of conduits with longitudinally aligned pattern. BJ fibroblasts cannot infiltrate through the SF wall, avoiding scar tissue formation on the lumen of the graft when used in vivo. These conduits have been demonstrated to be very versatile and fulfil with the requirements for their use in PNR.

Supplementary information: The online version contains supplementary material available at 10.1007/s44164-023-00050-3.

Nanostructured inorganic biomaterial emerged as the most essential platform to address traumatic and non-traumatic conditions of hard tissues in the current scenario. Synthetic inorganic biomaterials serve as an efficient and pathogen-free choice that overcomes the obstructions associated with autografts and allografts to promote new tissue regeneration, since nano-hydroxyapatite (nHAp) is a biomaterial that mimics the natural mineral composition of bones and teeth of human hard tissues, which is widely employed in orthopedics and dentistry. The nHAp-based materials exhibit bioactive, biocompatible, and osteoconductive features under in vitro and in vivo conditions. The brittle nature of synthetic nHAp leads to weak mechanical properties, which eventually confines the utility of nHAp in load-bearing applications. Hence, this review focuses on the recent trends in the fabrication and investigation of nHAp-based polymer nanocomposite scaffolds for bone regeneration. Employing different polymers and fabrication strategies would efficiently tailor the physicochemical properties, and tailor-made mechanical properties in competence with biodegradation, thereby enhancing their potential in biomedical utility, and exploring their efficacy under in vitro and in vivo conditions to make "HAp-based smart-biomaterials" for bone tissue engineering.

Purpose: Ischemic brain injury occurs when there is reduced or complete disruption of blood flow to a brain region, such as in stroke or severe traumatic brain injury. Even short interruptions can lead to devastating effects including excitotoxicity and widespread cell death. Despite many decades of research, there are still very few therapeutic options for patients suffering from brain ischemia.

Methods: We developed an in vitro brain ischemia model using our previously established 3D spheroids derived from primary postnatal rat cortex. These spheroids provide an in vivo-relevant model containing a similar cellular composition to the native cortex and a cell-synthesized extracellular matrix. This model is cost-effective, highly reproducible, and can be produced in a high-throughput manner, making it an ideal candidate for screening potential therapeutics. To study the cellular and molecular mechanisms of stroke in this model, spheroids were deprived of glucose, oxygen, or both oxygen and glucose for 24 h.

Results: Both oxygen and oxygen-glucose deprived spheroids demonstrated many of the hallmarks of ischemic brain injury, including a decrease in metabolism, an increase in neural dysfunction, breakdown in the neurovascular unit, and an increase in reactive astrocytes. Pretreatment of spheroids with the antioxidant agent N-acetylcysteine (NAC) mitigated the decrease in ATP after oxygen-glucose deprivation, was partially neuroprotective, and enhanced the expression of laminin.

Conclusion: This 3D cortical spheroid model provides a platform for studying ischemic injury and has the potential for screening therapeutics.

Supplementary information: The online version contains supplementary material available at 10.1007/s44164-023-00046-z.

The intestinal barrier is a complex interface of the human body, possessing the largest contact surface to nutrients and antigens and containing a major part of the immune system. It has to deal with continuous exposure to a broad mixture of essential, harmful, or useless substances and particles. In the context of plastic pollution and the ubiquitous occurrence of micro- and nanoplastics, oral exposure to such particles is of particular interest. Standard intestinal in vitro models, however, are unable to mimic the role of the immune system in the particle-exposed intestine. To allow for a closer look on the effect of particles on the intestinal immune system, we here developed a co-culture model to enable investigation of the epithelial brush border monolayer in a healthy and inflamed state. The model is based on well-established Caco-2 intestinal epithelial cells cultured in a Transwell™ system. Intraepithelial immune cells were mimicked by THP-1-derived M0-macrophages and MUTZ-3-derived dendritic cells. To fulfill the requirements needed for the investigation of particles, the co-culture system was developed without an additional matrix layer. Cell-cell contacts were established between interstitial and immune cells, and the Caco-2 standard cell culture medium was used, which is well-characterized for its role in defining the identity of particle dispersions. The model was characterized using confocal microscopy, membrane integrity measurements, and cytokine release assays from inflamed and healthy cells. Finally, the new co-culture model was used for investigation on polylactic acid, melamine formaldehyde resin, and polymethylmethacrylate plastic micro- and nanoparticles.

Supplementary information: The online version contains supplementary material available at 10.1007/s44164-023-00047-y.

[This corrects the article DOI: 10.1007/s44164-022-00015-y.].

[This corrects the article DOI: 10.1007/s44164-022-00037-6.].

The translational potential of promising anticancer medications and treatments may be enhanced by the creation of 3D in vitro models that can accurately reproduce native tumor microenvironments. Tumor microenvironments for cancer treatment and research can be built in vitro using biomaterials. Three-dimensional in vitro cancer models have provided new insights into the biology of cancer. Cancer researchers are creating artificial three-dimensional tumor models based on functional biomaterials that mimic the microenvironment of the real tumor. Our understanding of tumor stroma activity over the course of cancer has improved because of the use of scaffold and matrix-based three-dimensional systems intended for regenerative medicine. Scientists have created synthetic tumor models thanks to recent developments in materials engineering. These models enable researchers to investigate the biology of cancer and assess the therapeutic effectiveness of available medications. The emergence of biomaterial engineering technologies with the potential to hasten treatment outcomes is highlighted in this review, which also discusses the influence of creating in vitro biomimetic 3D tumor microenvironments utilizing functional biomaterials. Future cancer treatments will rely much more heavily on biomaterials engineering.

[This corrects the article DOI: 10.1007/s44164-022-00030-z.].

Cancer therapeutics are often highly toxic to the patient, and they often elicit rapid resistance in the tumour. Recent advances have suggested a potential new way in which we may improve on this, through two important concepts: (1) that multitudinous pathway alterations converge on a limited number of cancer cellular phenotypes, and (2) that these cancer cellular phenotypes depend on reactivation of developmental processes that are only minimally active in adult tissues. This provides a rationale for pursuing an approach of 'drugging the phenotype' focussed on targeting reactivated cellular processes from embryonic development. In this concepts paper, we cover these recent developments and their implications for the development of new cancer therapeutics that can avoid patient toxicity and acquired resistance. We then propose that in vitro tumour and developmental models can provide an experimental approach to identify and target the specific developmental processes at play, with a focus on the reactivation of developmental processes in the cancer stem cells that drive tumour progression and spread. Ultimately, the aim is to identify cellular processes that are specific to developmental phenotypes, are reactivated in cancer stem cells, and are essential to tumour progression. Therapeutically targeting these cellular processes could represent a new approach of 'drugging the phenotype' that treats the tumour whilst avoiding patient toxicity or the acquisition of therapeutic resistance.

Purpose: This 3D in vitro cancer model for propagation of patient-derived cells, using a synthetic self-assembling peptide gel, allows the formation of a fully characterised, tailorable tumour microenvironment. Unlike many existing 3D cancer models, the peptide gel is inert, apart from molecules and motifs deliberately added or produced by cells within the model.

Methods: Breast cancer patient-derived xenografts (PDXs) were disaggregated and embedded in a peptide hydrogel. Growth was monitored by microscopic examination and at intervals, cells were extracted from the gels and passaged on into fresh gels. Passaged cells were assessed by qPCR and immunostaining techniques for the retention of characteristic markers.

Results: Breast cancer PDXs were shown to be capable of expansion over four or more passages in the peptide gel. Contaminating mouse cells were found to be rapidly removed by successive passages. The resulting human cells were shown to be compatible with a range of common assays useful for assessing survival, growth and maintenance of heterogeneity.

Conclusions: Based on these findings, the hydrogel has the potential to provide an effective and practical breast cancer model for the passage of PDXs which will have the added benefits of being relatively cheap, fully-defined and free from the use of animals or animal products. Encapsulated cells will require further validation to confirm the maintenance of cell heterogeneity, genotypes and phenotypes across passage, but with further development, including the addition of bespoke cell and matrix components of the tumour microenvironment, there is clear potential to model other cancer types.

Supplementary information: The online version contains supplementary material available at 10.1007/s44164-023-00048-x.