Osteoarthritis severely decreases the elasticity and hardness of knee joint cartilage: A nanoindentation study

The nanoindentation method was applied to determine the elastic modulus and hardness of knee articular cartilage. Cartilage samples from both high weight bearing (HWB) and low weight bearing (LWB) femoral condyles were collected from patients diagnosed with osteoarthritis (OA). The mean elastic modulus of HWB cartilage was 4.46 ± 4.44 MPa in comparison to that of the LWB region (9.81 ± 8.88 MPa, p < 0.001). Similarly, the hardness was significantly lower in HWB tissue (0.317 ± 0.397 MPa) than in LWB cartilage (0.455 ± 0.434 MPa, p < 0.001). When adjusted to patients’ ages, the mean elastic modulus and hardness were both significantly lower in the age group over 70 years (p < 0.001). A statistically significant difference in mechanical parameters was also found in grade 3 and 4 OA. This study provides an insight into the nanomechanical properties of the knee articular cartilage and provides a starting point for personalized cartilage grafts that are compatible with the mechanical properties of the native tissue

Regulation of CYP17 gene expression in adrenocortical cells by transforming growth factor-&#946;

W korze nadnerczy geny CYP, kodujące składniki kompleksów enzymatycznych hydroksylaz steroido-wych, są regulowane przez hormony i czynniki wzrostu. Cytochrom P450c17, składnik kompleksu 17&#945;&#8211;hydroksylazy/17,20&#8211;liazy, konieczny do produkcji androgenów nadnerczowych, jest kodowany przez CYP17 i ekspresja tego genu, zarówno podstawowa, jak i stymulowana, wymagają steroidogennego czynnika 1 (SF-1). Nasze badania, prowadzone na komórkach kory nadnerczy ludzkich NCI-H295R, wskazują, że TGF-&#946;, działając za pośrednictwem ścieżki sygnałowej białek Smad, hamuje zarówno podstawową, jak i stymulowaną przez cAMP transkrypcję CYP17 i wymaga fragmentu -485/-433 promotora CYP17, zawierającego potencjalny element odpowiedzi na SP-1. Aby wyjaśnić mechanizm zahamowania transkrypcji CYP17 przez TGF-&#946;, badano także ekspresję SF-1. Wykazano, że aktywator cyklazy adenilanowej, for-skolina, która imituje działanie ACTH - wzmaga, podczas gdy TGF-&#946; - obniża poziom transkryptu SF-1. Maksymalne obniżenie poziomu podstawowego mRNA dla SF-1 obserwowano po 48 godz. inkubacji komórek z TGF-&#946; (60% zahamowania), podczas gdy w komórkach inkubowanych z forskoliną i TGF-&#946; obserwowano 50% zahamowanie ekspresji już po 6 godz. inkubacji. W obu przypadkach efekt dotyczył transkrypcji genu i towarzyszyły mu równoległe zmiany stężenia produktu białkowego genu. Wnioskuje się, że ekspresja CYP17 jest regulowana negatywnie przez TGF-&#946; na poziomie transkrypcji poprzez ścieżkę sygnałową białek Smad i ten efekt wymaga fragmentu -483/-433 promotora, zawierającego potencjalny element odpowiedzi na SP-1. Efekt TGF-&#946; na ekspresję CYP17 jest specyficzny, ponieważ w tych samych warunkach ekspresja CYP11A1 pozostała niezmieniona i może przynajmniej w części być spowodowany zahamowaniem transkrypcji SF-1In the adrenal cortex, CYP genes encoding cytochromes P450 components of steroid hydroxylases are regulated by hormones and growth factors. Cytochrome P450c17, constituent of 17&#945;-hydroxylase/17,20-lyase enzyme complex, essential for production of adrenal androgens, is encoded by CYP17 and the expression of this gene, both basal and ACTH-induced, requires steroidogenic factor-1 (SF-1).Our studies conducted in human adrenocortical NCI-H295R cells indicated that TGF-&#946; acting through the Smad protein pathway, inhibited both basal and cAMP-stimulated transcription of CYP17, and that the &#8211;483/-433 fragment of CYP17 promoter, which contains a putative Sp1 response element, is the target for the inhibitory action of TGF-&#946;. To elucidate the mechanism of inhibition of CYP17 transcription by TGF-&#946;, the expression of SF-1 was also investigated. It was demonstrated that adenylyl cyclase activator, forskolin which mimicks the effect of ACTH, increased, while TGF-&#946; decreased the level of SF-1 transcript. The maximal decrease of basal SF-1 mRNA level was observed after 48 h of incubation of the cells with TGF-&#946; (60% inhibition), while in forskolin-treated cells TGF-&#946; caused 50% decrease in Sf-1 transcript level, already after 6 h of treatment. In both cases the effect was transcriptional and was accompanied by parallel changes in the level of the protein product of the gene. It is concluded that CYP17 expression is negatively regulated by TGF-&#946; at the transcriptional level via Smad protein pathway, and that this effect requires the &#8211;483/-433 fragment of CYP17 promoter containing a putative Sp1 response element. The effect of TGF-&#946; on the expression of CYP17 is specific, since under the same conditions the expression of CYP11A1 is unaffected, and could be, at least in part, due to the inhibition of SF-1 transcription

Utilization of Carbon Nanotubes in Manufacturing of 3D Cartilage and Bone Scaffolds

Cartilage and bone injuries are prevalent ailments, affecting the quality of life of injured patients. Current methods of treatment are often imperfect and pose the risk of complications in the long term. Therefore, tissue engineering is a rapidly developing branch of science, which aims at discovering effective ways of replacing or repairing damaged tissues with the use of scaffolds. However, both cartilage and bone owe their exceptional mechanical properties to their complex ultrastructure, which is very difficult to reproduce artificially. To address this issue, nanotechnology was employed. One of the most promising nanomaterials in this respect is carbon nanotubes, due to their exceptional physico-chemical properties, which are similar to collagens—the main component of the extracellular matrix of these tissues. This review covers the important aspects of 3D scaffold development and sums up the existing research tackling the challenges of scaffold design. Moreover, carbon nanotubes-reinforced bone and cartilage scaffolds manufactured using the 3D bioprinting technique will be discussed as a novel tool that could facilitate the achievement of more biomimetic structures

Calorimetric and spectroscopic studies characterization of newborn rat’ blood serum after maternal administration of cyclophosphamide

Differential scanning microcalorimetry (DSC) and UV–VIS absorption spectroscopy were used to obtain the characteristics of blood serum from newborn rat’ after maternal treatment with cyclophosphamide in comparison with control. The obtained DSC curves reveal a complex endothermic peak due to the unfolding process of various serum proteins. Thermal profiles and absorption spectra of blood serum are sensitive to the age of newborns as well as to effect of maternal administration of cyclophosphamide. The most significant disturbances in serum proteome were observed for 14-day old newborns. The thermodynamic parameters: enthalpy change (DH), the normalized first moment (M1) of the thermal transition with respect to the temperature axis and the ratio of Cp ex at 70 and 60 C describing denaturation contributions of globulin forms in respect to unliganded albumin with haptoglobin was estimated. Moreover, the second derivative spectroscopy in the UV region was used to resolve the complex protein spectrum. The differences in blood serum detected by DSC and UV–VIS confirm a potential usefulness of these methods for diagnostic and monitoring changes with age as well as the pathological state of blood serum

Meniscus suture provides better clinical and biomechanical results at 1-year follow-up than meniscectomy

BACKGROUND: Surgery of meniscus tear results in limitation of function. The aim of study was functional assessment of knee 1 year after surgery with two techniques in cases of the medial meniscus tear followed by the same supervised rehabilitation. MATERIALS AND METHODS: A total of 30 patients with good KOSS scores constituted two equal groups after partial meniscectomy or meniscus suture. Measurements of knee extensors and flexors muscles peak torques were performed with angular velocities 60, 180, 240 and 300 s(−1) using Biodex IV system. One-leg-hop and one-leg-rising tests ascertained the function of operated knee. Results of examinations were compared with reference to healthy volunteers. Results of biomechanical and clinical studies were correlated to create complex and objective method evaluating treatment. RESULTS: Extensors peak torque values at 60 s(−1) angular velocity and H/Q coefficient were decreased after meniscectomy more than meniscus suture in comparison to healthy volunteers (P ≤ 0.001; P ≤ 0.05). Analysis of functional tests revealed that patients after meniscectomy showed difference between operated and non-operated knee (P ≤ 0.01) while patients with meniscus suture differed the least to controls (P ≤ 0.05). Extensors peak torque values at 60 s(−1) angular velocity correlated with results of one-leg-rising test. CONCLUSION: Results suggest worse functional effects when meniscectomy is applied which implies modification of the rehabilitative methods in a postoperative period

Impact of CoreValve size selection based on multi-slice computed tomography on paravalvular leak after transcatheter aortic valve implantation

Background: Paravalvular leak (PVL) has significant impact on long-term outcomes in patients after transcatheter aortic valve implantation (TAVI). This study sought to determine whether multi-slice computed tomography (MSCT)-guided valve selection reduces PVL after CoreValve implantation. Methods: The analysis encompassed 69 patients implanted with CoreValve and were divided into two groups. In Group I (30 patients), valve selection was based on standard procedures, in Group II (39 patients), on MSCT measurements. Paravalvular leak was assessed with angiography and echocardiography. Results: Multi-slice computed tomography results influenced a change of decision as to the size of the implanted valve in 12 (30.9%) patients in Group II and would have caused the decision to change in 9 (37.5%) patients in Group I. The degree of oversizing in Group I and II was 12.8% ± ± 7.6% vs. 18.6% ± 5.1% (p = 0.0006), respectively. The oversizing among the patients with leak degree of 0–1 and ≥ 2 was 18.1% ± 6.0% and 12.8% ± 7.4% (p = 0.0036). Angiographic assessment indicated post-procedural PVL ≥ 2 in 50% of patients in Group I and 20.5% in Group II (p = 0.01), while echocardiographic assessment indicated the same in 73.3% of patients in Group I and 45.6% in Group II (p = 0.0136). The composite endpoint occurred in 26.6% (8/30) patients in Group I vs. 5.1% (2/39) patients in Group II (p = 0.0118). Conclusions: Selecting the CoreValve device based on MSCT resulted in smaller rates of PVL and less frequent composite endpoint. In 1/3 of patients MSCT led to a change of the valve size. The degree of oversizing had a significant impact on PVL