Influence of software parameters on measurements in automatized image-based analysis of fat tissue histology

Dynamic synthesis and transport of fluorescent substances from moulting scorpions

Scorpion fluorescence under ultraviolet light is a well-known phenomenon, and its change is also a known biological feature during the scorpion moulting process. However, the synthesis and transport of fluorescent substances during the moulting stage remain unclear. In this study, in-depth investigations on the global fluorescence changes from the exoskeleton, fluorescence layer, coelomic fluid, and abdomen to the digestive glands indicated that the digestive glands, which occupy most of the space in the abdomen of the scorpion mesosoma segment, were responsible for synthesizing the fluorescent substances. More importantly, these fluorescent substances were produced in advance, before the moulting process, which contributed to the recovery of the fluorescent exoskeleton as early as possible. The synthesized fluorescent substances first entered the coelomic fluid, then successively passed through the inherent epithelial cell layer and two new formed endocuticle and exocuticle layers, and ultimately reached and became enriched in the new formed fluorescent layer, which was protected by the new epicuticle layer. These four new layers were the first to illustrate the structural features of the fluorescent exoskeleton. Due to the very soft body and the inability of the newly moulted scorpion to resist attacks from the predator, this special synthesis and transport strategy of the fluorescent substances could guarantee the rapid formation of the integrated fluorescent exoskeleton during the 24 h after ecdysis, which would be a novel biological feature during the scorpion evolution.

Evaluation of the Usability of a Low-Cost 3D Printer in a Tissue Engineering Approach for External Ear Reconstruction

The use of alloplastic materials instead of autologous cartilage grafts offers a new perspective in craniofacial reconstructive surgery. Particularly for regenerative approaches, customized implants enable the surgeon to restore the cartilaginous framework of the ear without donor site morbidity. However, high development and production costs of commercially available implants impede clinical translation. For this reason, the usability of a low-cost 3D printer (Ultimaker 2+) as an inhouse-production tool for cheap surgical implants was investigated. The open software architecture of the 3D printer was modified in order to enable printing of biocompatible and biologically degradable polycaprolactone (PCL). Firstly, the printing accuracy and limitations of a PCL implant were compared to reference materials acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA). Then the self-made PCL-scaffold was seeded with adipose-tissue derived stem cells (ASCs), and biocompatibility was compared to a commercially available PCL-scaffold using a cell viability staining (FDA/PI) and a dsDNA quantification assay (PicoGreen). Secondly, porous and solid patient-customized ear constructs were manufactured from mirrored CT-imagining data using a computer-assisted design (CAD) and computer-assisted manufacturing (CAM) approach to evaluate printing accuracy and reproducibility. The results show that printing of a porous PCL scaffolds was possible, with an accuracy equivalent to the reference materials at an edge length of 10 mm and a pore size of 0.67 mm. Cell viability, adhesion, and proliferation of the ASCs were equivalent on self-made and the commercially available PCL-scaffolds. Patient-customized ear constructs could be produced well in solid form and with limited accuracy in porous form from all three thermoplastic materials. Printing dimensions and quality of the modified low-cost 3D printer are sufficient for selected tissue engineering applications, and the manufacturing of personalized ear models for surgical simulation at manufacturing costs of EUR 0.04 per cell culture scaffold and EUR 0.90 (0.56) per solid (porous) ear construct made from PCL. Therefore, in-house production of PCL-based tissue engineering scaffolds and surgical implants should be further investigated to facilitate the use of new materials and 3D printing in daily clinical routine.

Zone-Dependent Architecture and Biochemical Composition of Decellularized Porcine Nasal Cartilage Modulate the Activity of Adipose Tissue-Derived Stem Cells in Cartilage Regeneration

Previous anatomical studies have shown different functional zones in human nasal septal cartilage (NC). These zones differ in respect to histological architecture and biochemical composition. The aim of this study was to investigate the influence of these zones on the fate of stem cells from a regenerative perspective. Therefore, decellularized porcine septal cartilage was prepared and subjected to histological assessment to demonstrate its equivalence to human cartilage. Decellularized porcine NC (DPNC) exposed distinct surfaces depending on two different histological zones: the outer surface (OS), which is equivalent to the superficial zone, and the inner surface (IS), which is equivalent to the central zone. Human adipose tissue-derived stem cells (ASCs) were isolated from the abdominal fat tissue of five female patients and were seeded on the IS and OS of DPNC, respectively. Cell seeding efficiency (CSE), vitality, proliferation, migration, the production of sulfated glycosaminoglycans (sGAG) and chondrogenic differentiation capacity were evaluated by histological staining (DAPI, Phalloidin, Live-Dead), biochemical assays (alamarBlue^®, PicoGreen^®, DMMB) and the quantification of gene expression (qPCR). Results show that cell vitality and CSE were not influenced by DPNC zones. ASCs, however, showed a significantly higher proliferation and elevated expression of early chondrogenic differentiation, as well as fibrocartilage markers, on the OS. On the contrary, there was a significantly higher upregulation of hypertrophy marker MMP13 (p < 0.0001) and GAG production (p = 0.0105) on the IS, whereas cell invasion into the three-dimensional DPNC was higher in comparison to the OS. We conclude that the zonal-dependent distinct architecture and composition of NC modulates activities of ASCs seeded on DPNC. These findings might be used for engineering of cartilage substitutes needed in facial reconstructive surgery that yield an equivalent histological and functional structure, such as native NC.

Combination Usage of AdipoCount and Image-Pro Plus/ImageJ Software for Quantification of Adipocyte Sizes

In recent decades, the prevalence of obesity has been rising. One of the major characteristics of obesity is fat accumulation, including hyperplasia (increase in number) and hypertrophy (increase in size). After histological staining, it is critical to accurately measure the number and size of adipocytes for assessing the severity of obesity in a timely fashion. Manual measurement is accurate but time-consuming. Although commercially available adipocyte counting tools, including AdipoCount, Image-Pro Plus, and ImageJ were helpful, limitations still exist in accuracy and time consuming. In the present study, we introduced the protocol of combined usage of these tools and illustrated the process with histological staining slides from adipose tissues of lean and obese mice. We found that the adipocyte sizes quantified by the tool combination were comparable as manual measurement, whereas the combined methods were more efficient. Besides, the recognition effect of monochrome segmentation image is better than that of color segmentation image. Overall, we developed a combination method to measure adipocyte sizes accurately and efficiently, which may be helpful for experimental process in laboratory and also for clinic diagnosis.

Experimental approach to nasal septal cartilage regeneration with adipose tissue-derived stem cells and decellularized porcine septal cartilage

BACKGROUND

Cartilage shortage is a major problem in facial reconstructive surgery. Prior studies have shown that decellularized porcine nasal septal cartilage (DPNC) seeded with primary human nasal chondrocytes enabled cartilage regeneration and showed potential as a replacement material for nasal cartilage. Since adipose tissue-derived stem cells (ASCs) are easily accessible and almost abundantly available, they appear to be a promising alternative to limited chondrocytes making the combination of DPNC and ASCs a feasible approach towards clinical translation. Thus, this study was intended to investigate the interactions between ASCs and DPNC in an in vitro model.

METHODS

DPNCs were seeded and 3D-cultured with primary human ASCs that were priorly characterized with trilineage differentiation and flow cytometry. Cell vitality and proliferation were evaluated by Live-Dead, alamarBlue, and PicoGreen assays. Chondrogenic differentiation was examined by DMMB assay and cryosectioning-based histology. Cell invasion within DPNC was visualized and quantified by fluorescent histology (DAPI, Phalloidin).

RESULTS

ASCs showed good adherence to DPNC and Live-Dead assay proved their viability over 2 weeks. AlamarBlueassay showed an increase in metabolic activity compared to 2D cultures, and PicoGreen assay demonstrated an increase of cell number within DPNC over time. Biochemical assays and histology added evidence of chondrogenic differentiation of 3D-cultured ASCs under the influence of chondrogenic induction medium. Fluorescent image analysis showed a significant increase of cell-occupied areas of scaffolds over time (P < .05).

CONCLUSIONS

DPNC scaffolds provided a suitable environment for ASCs that allowed good cell vitality, high proliferation, and chondrogenic differentiation. Thus, the use of ASCs and DPNC yields a promising alternative to the use of primary human chondrocytes. For facial cartilage tissue engineering, we regard ASCs as an attractive alternative to human nasal chondrocytes due to their better accessibility and availability. Further research will be necessary to determine long-term effects and in vivo outcomes of ASCs and DPNC in cartilage regeneration of the face.