Optimization of Three Dimensional Culturing of the HepG2 Cell Line in Fibrin Scaffold

Improvements in Maturity and Stability of 3D iPSC-Derived Hepatocyte-like Cell Cultures

Induced pluripotent stem cell (iPSC) technology enables differentiation of human hepatocytes or hepatocyte-like cells (iPSC-HLCs). Advances in 3D culturing platforms enable the development of more in vivo-like liver models that recapitulate the complex liver architecture and functionality better than traditional 2D monocultures. Moreover, within the liver, non-parenchymal cells (NPCs) are critically involved in the regulation and maintenance of hepatocyte metabolic function. Thus, models combining 3D culture and co-culturing of various cell types potentially create more functional in vitro liver models than 2D monocultures. Here, we report the establishment of 3D cultures of iPSC-HLCs alone and in co-culture with human umbilical vein endothelial cells (HUVECs) and adipose tissue-derived mesenchymal stem/stromal cells (hASCs). The 3D cultures were performed as spheroids or on microfluidic chips utilizing various biomaterials. Our results show that both 3D spheroid and on-chip culture enhance the expression of mature liver marker genes and proteins compared to 2D. Among the spheroid models, we saw the best functionality in iPSC-HLC monoculture spheroids. On the contrary, in the chip system, the multilineage model outperformed the monoculture chip model. Additionally, the optical projection tomography (OPT) and electrical impedance tomography (EIT) system revealed changes in spheroid size and electrical conductivity during spheroid culture, suggesting changes in cell-cell connections. Altogether, the present study demonstrates that iPSC-HLCs can successfully be cultured in 3D as spheroids and on microfluidic chips, and co-culturing iPSC-HLCs with NPCs enhances their functionality. These 3D in vitro liver systems are promising human-derived platforms usable in various liver-related studies, specifically when using patient-specific iPSCs.

Effects of polystyrene micro/nanoplastics on liver cells based on particle size, surface functionalization, concentration and exposure period

Micro/nanoplastics (MP/NP) contaminate our food and drinking water but their impact on human health has not been well-documented. The liver is one of the first organs that ingested MP/NP encounter and it has a major role in the clearance of xenobiotics. Therefore, the effects of polystyrene MP/NP on liver HepG2 cells were studied. Cellular responses to particles of various sizes (50-5000 nm) and surface functionalization (aminated, carboxylated or non-functionalized) were determined at different concentrations (0.1-100 μg/mL) and exposure periods (1-24 h). Smaller sized particles were internalized by HepG2 cells more avidly than larger particles regardless of functionalization; the highest uptake being for 50 and 100 nm aminated particles at lower concentrations. Confocal microscopy images of cells corroborated quantitative uptake results. Aminated particles were more toxic to the cells than carboxylated or non-functionalized particles. Among aminated particles smaller particles (50 and 100 nm) were more detrimental to cell viability compared to larger particles (1000 or 5000 nm) with toxicity increasing with concentration. Treatment with the particles for 4 h increased intracellular concentrations of Caspase-3 by 1.5-2.8 fold, but 24 h exposure to the particles attenuated this increase in Caspase-3 concentrations. A slight trend of higher Caspase-3 concentration in cells treated with larger particles (500-5000 nm) compared to smaller particles (50-200 nm) was observed, indicating that larger particles are more likely to direct cells toward apoptotic cell death upon 4 h exposure. Exposure of cells to large PS particles (500-5000 nm) upregulated interleukin-8 and the effect was enhanced at 24 h. Overall, the study demonstrated that smaller aminated particles were most toxic to hepatocytes, but larger particles induced apoptotic cell death or an inflammatory response depending on the length of exposure.

Bone Tissue Engineering in the Treatment of Bone Defects

Bones play an important role in maintaining exercise and protecting organs. Bone defect, as a common orthopedic disease in clinics, can cause tremendous damage with long treatment cycles. Therefore, the treatment of bone defect remains as one of the main challenges in clinical practice. Today, with increased incidence of bone disease in the aging population, demand for bone repair material is high. At present, the method of clinical treatment for bone defects including non-invasive therapy and invasive therapy. Surgical treatment is the most effective way to treat bone defects, such as using bone grafts, Masquelet technique, Ilizarov technique etc. In recent years, the rapid development of tissue engineering technology provides a new treatment strategy for bone repair. This review paper introduces the current situation and challenges of clinical treatment of bone defect repair in detail. The advantages and disadvantages of bone tissue engineering scaffolds are comprehensively discussed from the aspect of material, preparation technology, and function of bone tissue engineering scaffolds. This paper also summarizes the 3D printing technology based on computer technology, aiming at designing personalized artificial scaffolds that can accurately fit bone defects.

Biomaterial-based cell delivery strategies to promote liver regeneration

Chronic liver disease and cirrhosis is a widespread and untreatable condition that leads to lifelong impairment and eventual death. The scarcity of liver transplantation options requires the development of new strategies to attenuate disease progression and reestablish liver function by promoting regeneration. Biomaterials are becoming an increasingly promising option to both culture and deliver cells to support in vivo viability and long-term function. There is a wide variety of both natural and synthetic biomaterials that are becoming established as delivery vehicles with their own unique advantages and disadvantages for liver regeneration. We review the latest developments in cell transplantation strategies to promote liver regeneration, with a focus on the use of both natural and synthetic biomaterials for cell culture and delivery. We conclude that future work will need to refine the use of these biomaterials and combine them with novel strategies that recapitulate liver organization and function in order to translate this strategy to clinical use.

Lens-Free Imaging as a Sensor for Dynamic Cell Viability Detection Using the Neutral Red Uptake Assay

Neutral red is a low-cost supravital stain for determining cell viability. The standard protocol relies on a destructive extraction process to release the accumulated dye for endpoint spectrophotometric quantification. We report a non-destructive, live-cell quantification of neutral red uptake using a compact lens-free system. Two light sources indentify the cell perimeter and quantify neutral red uptake. The quantification occurs during staining, thus eliminating the destructive extraction process and reducing assay time. Our system enables live quantification for continuous high-throughput screening of cell viability within confined spaces such as incubators.

Characterization of biogenic Fe (III)-binding exopolysaccharide nanoparticles produced by Ralstonia sp. SK03

A new technological approach to nanoparticle synthesis is using microorganisms, such as bacteria, which have the ability to synthesize nontoxic nanoparticles with high biocompatibility. In addition, bacteria have strict control over size, structure, shape, and dimension of produced nanoparticles. In the present work, Fe (III)-binding exopolysaccharide (Fe-EPS) nanoparticles were biosynthesized by Ralstonia pickettii sp. SK03, a bacterium isolated from a mineral spring. 16S rRNA gene sequencing and biochemical tests were done for identification of the isolated bacterium. For the first time, critical biological and physicochemical properties of this iron oxide nanoparticle were characterized using Fourier Transform Infrared (FTIR) Spectroscopy, Transmission Electron Microscopy (TEM), Vibrating Sample Magnetometer (VSM), Dynamic Light Scattering (DLS), Thermogravimetric analysis (TGA), X-ray crystallography (XRD), Atomic absorption spectroscopy (AAS), and cell viability assays (MTT assay). The characterization results showed that Fe-EPS nanoparticles were composed of spherical ferrihydrite nanoparticles (with a size range of 1.2-2 nm), trapped in a polysaccharide matrix. The TGA analysis demonstrated that Fe-EPS nanoparticles contained ∼25.2% polysaccharide. Therefore, this polysaccharide matrix showed a very low magnetic saturation value (0.25 emu/g) and a large negative charge of -93.8 mV. In addition, treatment of hepatocarcinoma cell line (Hep-G2) with 1-500 µg/mL concentrations of Fe-EPS nanoparticles caused 40% increase in the cell viability, which indicated that the biosynthesized nanoparticles were nontoxic and biocompatible. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 2018 © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:1167-1176, 2018.

Effect of Fibrin Packing on Managing Hepatic Hemorrhage and Liver Wound Healing in a Model of Liver Stab Wound in Rat

OBJECTIVE

To evaluate the effect of fibrin perihepatic packing on controlling liver hemorrhage and liver wound healing.

METHODS

In this animal experimental study, 20 adult male Sprague Dawley rats, weighing 200-220 g, were included. Stab wound injury was created by number 15 scalpel, so that bilateral liver capsules and liver tissue were cut, and acute bleeding was accrued. The animals were divided into 2 study groups: control (with a primary gauze packing treatment) and test group (with fibrin packing treatment). Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total serum bilirubin (TSB) levels were measured as a liver function test during the treatment period. Blood loss was calculated for estimation of hepatic hemorrhage during surgery. After four weeks, the liver wound repair was evaluated by sampling and Hematoxylin and Eosin staining (H&E).

RESULTS

In the test group, all of animals were alive (mortality rate= 0%). Significantly, ALT and AST levels were raised after surgery, followed by a decrease ALT (p=0.783) and AST (p=0.947) to the normal level during 4 days. Estimated blood loss was 2.89 ± 0.73 mL (about 19.65% of estimated blood volume). Hematocrit levels returned to the normal level (p=0.109) after 48 hours. In the control group, the mortality rate was 50% during 12h after surgery. ALT (p=0.773) and AST (p=0.853) were decreased to normal level during 6 days, and estimated blood loss was 4.98 ± 0.77 mL (about 32.98% of estimated blood volume) in the remaining animals. Moreover, hematocrit levels returned to the normal level (p=0.432) after 72 hours. Estimated blood loss in the test group was significantly less than control group (p<0.001). Total serum bilirubin levels were not significantly different from the normal level, before and after surgery in both groups. Histopathology sections from the post-hepatectomy specimens showed that the site of the previous incision was completely repaired, and a dense fibrous septum was observed in both groups.

CONCLUSION

The fibrin dressing was effective in preventing blood loss and saving lives after a liver stab injury and major internal bleeding in the animal model of rat.