Abstract. The purpose of this study was to investigate the expression of different CD44 and hyaluronan synthase isoforms in cartilage, their alterations during the chondrocyte dedifferentiation process in monolayer culture and during the redifferentiation process on 3D scaffolds. Chondrocytes isolated from human articular cartilage were cultured as a monolayer for up to 36 days and were seeded on two different 3D scaffolds (HYAFF ® 11 and Bio-Gide ® ). Expression levels of CD44s, CD44-lt, CD44-st, HAS1, HAS2, HAS3 and UDPGD were determined by real-time RT-PCR at different time points. At the protein level CD44 and CD90 were analyzed by flow cytometry. HAS2 was found to be the predominantly expressed hyaluronan synthase in chondrocytes and was not subjected to any regulation during the dedifferentiation process. CD44s, CD44-lt, CD44-st and UDPGD, however, were upregulated immediately after cell isolation. In addition, a high cell density was found to significantly increase CD44-st and CD44-lt expression. Redifferentiation on 3D scaffolds reversed the increase of the CD44 expression. Our data point out that CD44 expression does not correlate with matrix assembly in chondrocytes and that CD44 has a regulatory function in chondrocytes, not necessarily on differentiation, but probably on proliferation.

Adaptive response mechanisms within a state-vector model provide a coherent explanation of the dose-response characteristics for in-vitro transformations and chromosomal aberrations. These results suggest the need for new experimental studies described in the paper.

Elevated levels of serum ferritin (SF) are observed in several types of cancer; however, little is known on the association between ferritin and glioma, the most frequent type of human primary brain tumour. Here we report that GBM patients show significantly increased pre-surgical SF levels (i.e. ferritinaemia) within the SF reference range and a marked ferritin immunoreactivity of resected tumour tissue. Our findings account for an indirect association between ferritin synthesis in glioma-tissue and altered SF levels, which limits the clinical value of SF as a tumour marker in glioma. Importantly, we show for the first time that GBM-derived glioma cells release ferritin in vitro, which exerts an apoptosis-stimulating activity. Albeit the pathophysiologic context of apoptosis induction by a tumour-derived ferritin remains to be defined, our findings account for a distinct growth-regulatory role of these ferritin species in tumour biology.

Infrared (IR)-A irradiation can be useful in back and musculoskeletal pain therapy. In this study joint and vertebral column pain and mobility were measured during two weeks of IR-A irradiation treatment of patients suffering from degenerative osteoarthritis of hip and knee, low back pain, or rheumatoid arthritis. Additionally, before and after IR-A treatment MDA serum levels were measured to check if MDA variations accompany changes in pain intensity and mobility. Two-hundred and seven patients were divided into verum groups getting IR-irradiation, placebo groups getting visible, but not IR irradiation, and groups getting no irradiation. In osteoarthritis significant pain reduction according to Visual Analogue Scale and mobility improvements occurred in the verum group. Even though beneficial mean value changes occurred in the placebo group, the improvements in the placebo and No Irradiation groups were without statistical significance. In low back pain, pain and mobility improvements (by 35-40%) in the verum group were found, too. A delayed (2nd week) mobility improvement in rheumatoid arthritis was seen. However, pain relief was seen immediately. In patients suffering from low back pain or rheumatoid arthritis, the pain and mobility improvements were accompanied by significant changes of MDA serum levels. However, MDA appears not a sensitive biofactor for changes of the pain intensity in degenerative osteoarthritis. Nevertheless, unaffected or lowered MDA levels during intensive IR-A therapy argue against previous reports on free radical formation upon infrared. In conclusion, rapid beneficial effects of IR-A towards musculoskeletal pain and joint mobility loss were demonstrated.

Evidence suggests that the increased production of free radicals and reactive oxygen species lead to cellular aging. One of the consequences is lipid peroxidation generating reactive aldehydic products, such as 4-hydroxynonenal (HNE) that modify proteins and form adducts with DNA bases. To prevent damage by HNE, it is metabolized. The primary metabolic products are the glutathione conjugate (GSH-HNE), the corresponding 4-hydroxynonenoic acid (HNA), and the alcohol 1,4-dihydroxynonene (DHN). Since HNE metabolism can potentially change during in vitro aging, cell cultures of primary human dermal fibroblasts from several donors were cultured until senescence. After different time points up to 30 min of incubation with 5 µM HNE, the extracellular medium was analyzed for metabolites via liquid chromatography coupled with electrospray ionization mass spectrometry (LC/ESI-MS). The metabolites appeared in the extracellular medium 5 min after incubation followed by a time-dependent increase. But, the formation of GSH-HNL and GSH-DHN decreased with increasing in vitro age. As a consequence, the HNE levels in the cells increase and there is more protein modification observed. Furthermore, after 3 h of incubation with 5 µM HNE, younger cells showed less proliferative capacity, while in older cells slight increase in the mitotic index was noticed.Antioxidants 2020, 9, 150 2 of 15 aging are cross-linked through neuropeptides and cytokines that maintain communication between the neuroendocrine and the immune system [5]. The free radical theory explains aging as a consequence of cumulative oxidative damage caused by endogenous free radicals [6]. This theory has been criticized in the past because there was no experimental support that free radicals exist in the living organism. However, after work on electron paramagnetic resonance and the identification of the hydroxyl radical, and particularly after the enzyme superoxide dismutase (SOD) was discovered, this theory had scientific proof that free radicals can be generated endogenously [7,8].Increased production of reactive oxygen species (ROS) in aging is associated with increased damage to biomolecules [9]. The accumulation of oxidative damage leads to the emergence of various pathophysiological conditions, including age-related neurodegenerative diseases [10,11]. ROS cause damage to lipids, leading to their oxidative deterioration and production of α,β-unsaturated aldehydes [12,13]. 4-Hydroxynonenal (HNE) is a major breakdown product of ω-6-polyunsaturated fatty acids (e.g., linoleic, 18:2 and arachidonic acid, 20:4), and it has been reported to be a cytotoxic and genotoxic molecule [14][15][16]. Unlike free radicals which react only with biomolecules in their vicinity due to their short half-life, byproducts of lipid peroxidation are more stable and react with target molecules that are far from the place of their origin. As with the other reactive species, proteins react with HNE and form adducts eventually impairing protein function. Amino and sulphydryl groups of cysteine, ...