Cultivation of Human Oral Mucosal Explants on Contact Lenses

Potency assays and biomarkers for cell-based advanced therapy medicinal products

Advanced Therapy Medicinal Products (ATMPs) based on somatic cells expanded in vitro, with or without genetic modification, is a rapidly growing area of drug development, even more so following the marketing approval of several such products. ATMPs are produced according to Good Manufacturing Practice (GMP) in authorized laboratories. Potency assays are a fundamental aspect of the quality control of the end cell products and ideally could become useful biomarkers of efficacy in vivo. Here we summarize the state of the art with regard to potency assays used for the assessment of the quality of the major ATMPs used clinic settings. We also review the data available on biomarkers that may substitute more complex functional potency tests and predict the efficacy in vivo of these cell-based drugs.

Taking molecular pathology to the next level: Whole slide multicolor confocal imaging with the Pannoramic Confocal digital pathology scanner

The emergence and fast advance of digital pathology allows the acquisition, digital storage, interactive recall and analysis of morphology at the tissue level. When applying immunohistochemistry, it also affords the correlation of morphology with the expression of one or two specific molecule of interest. The rise of fluorescence pathology scanners expands the number of detected molecules based on multiplex labeling. The Pannoramic Confocal (created by 3DHistech, Hungary) is a first-of-the-kind digital pathology scanner that affords not only multiplexed fluorescent detection on top of conventional transmission imaging, but also confocality. We have benchmarked this scanner in terms of stability, precision, light efficiency, linearity and sensitivity. X-Y stability and relocalisation precision were well below resolution limit (≤50 nm). Light throughput in confocal mode was 4-5 times higher than that of a point scanning confocal microscope, yielding similar calculated confocal intensities but with the potential for improving signal to noise ratio or scan speed. Response was linear with R²  ≥ 0.9996. Calibrated measurements showed that using indirect labeling ≥2000 molecules per cell could be well detected and imaged on the cell surface. Both standard-based and statistical post-acquisition flatfield corrections are implemented. We have also measured the point spread function (PSF) of the instrument. The dimensions of the PSF are somewhat larger and less symmetric than of the theoretical PSF of a conventional CLSM, however, the spatial homogeneity of these parameters allows for obtaining a specific system PSF for each optical path and using it for optional on-the-fly deconvolution. In conclusion, the Pannoramic Confocal provides sensitive, quantitative widefield and confocal detection of multiplexed fluorescence signals, with optical sectioning and 3D reconstruction, in addition to brightfield transmission imaging. High speed scanning of large samples, analysis of tissue heterogeneity, and detection of rare events open up new ways for quantitatively analyzing tissue sections, organoid cultures or large numbers of adherent cells.

Corneal Repair and Regeneration: Current Concepts and Future Directions

The cornea is a unique tissue and the most powerful focusing element of the eye, known as a window to the eye. Infectious or non-infectious diseases might cause severe visual impairments that need medical intervention to restore patients' vision. The most prominent characteristics of the cornea are its mechanical strength and transparency, which are indeed the most important criteria considerations when reconstructing the injured cornea. Corneal strength comes from about 200 collagen lamellae which criss-cross the cornea in different directions and comprise nearly 90% of the thickness of the cornea. Regarding corneal transparency, the specific characteristics of the cornea include its immune and angiogenic privilege besides its limbus zone. On the other hand, angiogenic privilege involves several active cascades in which anti-angiogenic factors are produced to compensate for the enhanced production of proangiogenic factors after wound healing. Limbus of the cornea forms a border between the corneal and conjunctival epithelium, and its limbal stem cells (LSCs) are essential in maintenance and repair of the adult cornea through its support of corneal epithelial tissue repair and regeneration. As a result, the main factors which threaten the corneal clarity are inflammatory reactions, neovascularization, and limbal deficiency. In fact, the influx of inflammatory cells causes scar formation and destruction of the limbus zone. Current studies about wound healing treatment focus on corneal characteristics such as the immune response, angiogenesis, and cell signaling. In this review, studied topics related to wound healing and new approaches in cornea regeneration, which are mostly related to the criteria mentioned above, will be discussed.