M. Maj

Adipose-Derived Stem Cells as a Tool in Cell-Based Therapies

Recent development in stem cell isolation methods and expansion under laboratory conditions create an opportunity to use those aforementioned cells in tissue engineering and regenerative medicine. Particular attention is drawn towards mesenchymal stem cells (MSCs) being multipotent progenitors exhibiting several unique characteristics, including high proliferation potential, self-renewal abilities and multilineage differentiation into cells of mesodermal and non-mesodermal origin. High abundance of MSCs found in adipose tissue makes it a very attractive source of adult stem cells for further use in regenerative medicine applications. Despite immunomodulating properties of adipose-derived stem cells (ASCs) and a secretion of a wide variety of paracrine factors that facilitate tissue regeneration, effectiveness of stem cell therapy was not supported by the results of clinical trials. Lack of a single, universal stem cell marker, patient-to-patient variability, heterogeneity of ASC population combined with multiple widely different protocols of cell isolation and expansion hinder the ability to precisely identify and analyze biological properties of stem cells. The above issues contribute to conflicting data reported in literature. We will review the comprehensive information concerning characteristic features of ASCs. We will also review the regenerative potential and clinical application based on various clinical trials.

Collagen/elastin hydrogels cross-linked by squaric acid.

Hydrogels based on collagen and elastin are very valuable materials for medicine and tissue engineering. They are biocompatible; however their mechanical properties and resistance for enzymatic degradation need to be improved by cross-linking. Up to this point many reagents have been tested but more secure reactants are still sought. Squaric acid (SqAc), 3,4-dihydroxy 3-cyclobutene 1,2-dione, is a strong, cyclic acid, which reacts easily with amine groups. The properties of hydrogels based on collagen/elastin mixtures (95/5, 90/10) containing 5%, 10% and 20% of SqAc and neutralized via dialysis against deionized water were tested. Cross-linked, 3-D, transparent hydrogels were created. The cross-linked materials are stiffer and more resistant to enzymatic degradation than those that are unmodified. The pore size, swelling ability and surface polarity are reduced due to 5% and 10% of SqAc addition. At the same time, the cellular response is not significantly affected by the cross-linking. Therefore, squaric acid would be regarded as a safe, effective cross-linking agent.

Does the Harvesting Technique Affect the Properties of Adipose-Derived Stem Cells? - The Comparative Biological Characterization.

The objective of this study was to evaluate complex biological properties of human stem cells isolated from adipose tissue (ASCs) harvested utilizing different methods: surgical resection (R), power‐assisted liposuction (PAL), and laser‐assisted liposuction (LAL). ASCs were isolated from healthy donors, due to surgical resection, power‐, and laser‐assisted liposuction. Isolated cells were characterized by their clonogenicity, proliferation rate, doubling time, multilineage differentiation, and senescence potential. The average number of ASCs from 1g/1 ml of solid adipose tissue/lipoaspirate was 2.9 × 105 ± 2.4 × 105, 1.1 × 105 ± 0.8 × 105, and 1.2 × 105 ± 0.7 × 105, respectively, for ASCsR, ASCsPAL, and ASCsLAL. However, number of colonies formed by ASCsR and ASCsPAL was significantly higher compared to the average number of colonies formed by ASCsLAL. Also, in comparison to other analyzed cell groups, ASCsPAL obtained the highest proliferative activity. All analyzed cells were characterized by stable expression of CD90 and CD44 markers during prolonged culture. Expression of CD34 and CD45 markers was decreasing in subsequent passages. Presented study shows that different ASCs collection method affects some basic characteristics of these cells, such as number of isolated cells, clonogeneity, or doubling time. J. Cell. Biochem. 118: 1097–1107, 2017.

Anti-proliferative and cytotoxic activity of rosuvastatin against melanoma cells

Introduction Statins are considered potential candidate agents for melanoma chemoprevention. Statin-induced mevalonate pathway inhibition leads to reduction of cholesterol synthesis and also to decreased cellular levels of non-steroidal isoprenoids, geranylgeranyl pyrophosphate and farnesyl pyrophosphate. This results in the impairment of protein prenylation which affects carcinogenesis. Aim To analyze anti-proliferative and cytotoxic activity of rosuvastatin against melanoma cells. Material and methods Melanoma cell lines (A375 and WM1552C) and normal fibroblasts (BJ) were used as the primary research material. Cells were treated with rosuvastatin at concentrations ranging from 0.01 µM to 10 µM. Cell viability was analyzed with the use of an MTT assay. Expression of proliferation marker Ki67 was assessed on the basis of immunofluorescence staining. Results Rosuvastatin reduced A375 and BJ cell viability in a time- and dose-dependent manner. After 72 h incubation, the IC50, half maximal inhibitory concentration, was 2.3 µM for melanoma cells and 7.4 µM for normal fibroblasts. In turn, rosuvastatin exhibited relatively lower activity against WM1552C cells. A significant reduction of Ki67 expression was also noted for BJ fibroblasts after prolonged incubation with the tested drug. Conclusions The results indicate that the anti-melanoma properties of rosuvastatin are highly dependent on the tumor cell line assessed. However, the concentrations required to decrease melanoma cell viability in vitro exceed the plasma concentrations reached in patients treated with rosuvastatin at well-tolerated doses. What is more disturbing, reduction of proliferation and viability observed in BJ fibroblasts indicated that rosuvastatin at high doses may be toxic for normal cells.

Influence of Mesenchymal Stem Cells Conditioned Media on Proliferation of Urinary Tract Cancer Cell Lines and their Sensitivity to Ciprofloxacin

Mesenchymal stem cells (MSCs) are known to interact with cancer cells through direct cell‐to‐cell contact and secretion of paracrine factors, although their exact influence on tumor progression in vivo remains unclear. To better understand how fetal and adult stem cells affect tumors, we analyzed viability of human renal (786‐0) and bladder (T24) carcinoma cell lines cultured in conditioned media harvested from amniotic fluid‐derived stem cells (AFSCs) and adipose‐derived stem cells (ASCs). Both media reduced metabolic activity of 786‐0 cells, however, decreased viability of T24 cells was noted only after incubation with conditioned medium from ASCs. To test the hypothesis that MSCs‐secreted factors might be involved in chemoresistance acquisition, we further analyzed influence of mesenchymal stem cell conditioned media (MSC‐CM) on cancer cells sensitivity to ciprofloxacin, that is considered as potential candidate agent for urinary tract cancers treatment. Significantly increased resistance to tested drug indicates that MSCs may protect cancer cells from chemotherapy. J. Cell. Biochem. 118: 1361–1368, 2017.

Research on possible medical use of silk produced by caddisfly larvae of Hydropsyche angustipennis (Trichoptera, Insecta)

Silk products are used in medicine as biomaterials, and are particularly promising as scaffolds in tissue engineering. To date only silkworm and spider silk medical potential has been evaluated, whereas the possible application of the material spun by caddisflies in wet environment has not been examined. Biomedical application of every natural material requires biocompatibility testing and evaluation of unique microbiological and mechanical properties. This article focuses on silk fibers formed in caddisflies cocoons of Hydropsyche angustipennis (Insecta, Trichoptera) larvae. Preliminary biological evaluation shows that trichopteran silk is not cytotoxic to human cells. Caddisfly silk itself does not possess antiseptic properties and thus sterilization is indispensable for its application in medicine. Among tested methods of sterilization and disinfection only thermal methods (tyndallization and autoclaving) enabled complete eradication of bacteria and gave fully sterile material. Caddisfly silk appeared to be resistant to high temperature. Fully sterile fibers can be stored without a loss of breaking force and tensile strength. Our work shows that trichopteran silk has a significant potential to be used as a biomaterial.

The interplay between adipose-derived stem cells and bladder cancer cells

Tissue engineering approaches offer alternative strategies for urinary diversion after radical cystectomy. Possible triggering of cancer recurrence remains, however, a significant concern in the application of stem-cell based therapies for oncological patients. Soluble mediators secreted by stem cells induce tissue remodelling effects, but may also promote cancer cells growth and metastasis. We observed a substantial increase in the concentration of IL-6 and IL-8 in the secretome of adipose-derived stem cells (ASCs) co-cultured with bladder cancer cells. Concentrations of GM-CSF, MCP-1 and RANTES were also elevated. Bioactive molecules produced by ASCs increased the viability of 5637 and HT-1376 cells by respectively 15.4% and 10.4% (p < 0.0001). A trend in reduction of adhesion to ECM components was also noted, even though no differences in β-catenin expression were detected. When HT-1376 cells were co-cultured with ASCs their migration and invasion increased by 24.5% (p < 0.0002) and 18.2% (p < 0.002). Expression of p-ERK1/2 increased in 5637 cells (2.2-fold; p < 0.001) and p-AKT in HB-CLS-1 cells (2.0-fold; p < 0.001). Our results confirm that ASCs crosstalk with bladder cancer cells in vitro what influences their proliferation and invasive properties. Since ASCs tropism to tumour microenvironment is well documented their application towards post-oncologic reconstruction should be approached with caution.