45,099 research outputs found
Surface nanostructuring of bioresorbable implants to induce osteogenic differentiation of human mesenchymal stromal cells
No full textSurface nanostructuring of bioresorbable polymers is a promising solution for tissue regeneration therapies, as such nanostructured implants non-toxically degrade after producing localized and prolonged stimuli. In this work, a process chain for the fabrication of bioresorbable polymer implants was developed and validated. The implants present surface arrays of nanopillars whose main design parameters were optimized to induce the osteogenic differentiation of human stem cells. In vitro and in vivo cell experiments provided evidence for the potential application in tissue regeneration and revealed that nanopillars' diameter, height, and spacing need to be independently optimized to effectively promote osteogenic differentiation
Electroporation of 3D-Cultured Breast Cancer Cells Elicits T Lymphocyte-Mediated Killing
No full textBackground: Electrochemotherapy (ECT) is emerging as a powerful strategy to induce immunogenic cell death and profoundly reshape the tumor microenvironment. However, the specific immunomodulatory role of electric pulses, independently of chemotherapeutic agents, remains to be fully elucidated. This study investigates the potential of high-voltage electroporation, as used in ECT protocols, to stimulate immune responses in breast cancer. Materials and Methods: A 3D hydrogel-based culture system was used to generate uniform spheroids from HCC1954 breast cancer cells. Electroporation was applied with increasing electric field strengths (0–1000 V/cm) to modulate membrane permeability. Spheroids were then co-cultured with phytohemagglutinin-stimulated Jurkat cells or primary human CD4+/CD8+ T lymphocytes. Electroporation efficiency was assessed using propidium iodide (PI) staining. T cell-mediated cancer cell mortality was assessed through cancer cell viability assay via flow cytometry. Expression of Interleukin-2 (IL-2), Tumour Necrosis Factor alpha (TNF-α), and Interferon gamma (IFN-γ) was evaluated to assess T cell immune activation. Results: Electroporation at 600 and 1000 V/cm caused marked structural changes in the spheroids. At 1000 V/cm, a necrotic core was observed, surrounded by a layer of viable but stressed cells, whereas 600 V/cm resulted in a favorable proportion of successfully electroporated cells while preserving overall cell viability. These heterogeneous responses promoted differential immune recognition and cytotoxic targeting of cancer cells in co-culture experiments with immune cells. In co-culture, spheroids treated at 600 V/cm increased T cell activation and promoted targeted tumor cell killing. These effects were confirmed using both Jurkat cells and primary human lymphocytes. Gene expression analysis revealed upregulation of pro-inflammatory cytokines, indicating enhanced immunogenicity following high-voltage electroporation. Conclusions: High-voltage electroporation alone can increase the immunogenic potential of breast cancer cells and promote T cell-mediated anti-tumor activity. These findings support its application as a standalone immunomodulatory strategy and lay the groundwork for its integration into combined immunotherapeutic approaches
Nonclassic endogenous regulators of angiogenesis
No full textAngiogenesis, the process through which new blood vessels arise from preexisting ones, is regulated by several "classic" factors, among which the most studied are vascular endothelial growth factor (VEGF) and fibroblast growth factor-2 (FGF-2). In recent years, investigations showed that, in addition to the classic factors, numerous endogenous peptides play a relevant regulatory role in angiogenesis. Such regulatory peptides, each of which exerts well-known specific biological activities, are present, along with their receptors, in the blood vessels and may take part in the control of the "angiogenic switch." An in vivo and in vitro proangiogenic effect has been demonstrated for erythropoietin, angiotensin II (ANG-II), endothelins (ETs), adrenomedullin (AM), proadrenomedullin N-terminal 20 peptide (PAMP), urotensin-II, leptin, adiponectin, resistin, neuropeptide-Y, vasoactive intestinal peptide (VIP), pituitary adenylate cyclase-activating polypeptide (PACAP), and substance P. There is evidence that the angiogenic action of some of these peptides is at least partly mediated by their stimulating effect on VEGF (ANG-II, ETs, PAMP, resistin, VIP and PACAP) and/or FGF-2 systems (PAMP and leptin). AM raises the expression of VEGF in endothelial cells, but VEGF blockade does not affect the proangiogenic action of AM. Other endogenous peptides have been reported to exert an in vivo and in vitro antiangiogenic action. These include somatostatin and natriuretic peptides, which suppress the VEGF system, and ghrelin, that antagonizes FGF-2 effects. Investigations on "nonclassic" regulators of angiogenesis could open new perspectives in the therapy of diseases coupled to dysregulation of angiogenesis
Einfluss des Ausdauertrainings auf die Ergebnisse des Conconi Test
No full textCilj istraživanja bilo je proučavanje promjena frekvencije srca (FS) u Conconijevom testu, kao posljedica treninga izdržljivosti kod skijaša trkača. Poznato je, da trening izdržljivosti snižava FS kod istog opterećenja ali povećava brzinu trčanja kod praga defleksije v d. Kako se mijenja FS kod ovog testa u pripremi skijaša trkača, koji u svom treningu promjene tri vrste opterećenja: atletsko trčanje, trčanje na rolkama i skijaško trčanje, do sada nije poznato, a potrebno je znati, da li je moguće radi procjene trenutne kvalitete skijaša trkača upotrebiti i Conconijev test. Sedam treniranih skijaša trkača: 4 juniora t 3 seniora sudjelovalo je u eksperiment od lipnja do siječnja. Svaki od njih jednom mjesečno testiran je Conconijevim testom. Trening u tom razdoblju znatno je promijenio brzinu trčanja v d kod seniora od 46 +- 0.1 m/s u lipnju, do 4.9 +- 0.1 m/s u rujnu, da bi kasnije fluktuirala na istoj razini do siječnja, kad se v d opet povećala na 5.2 +- 0.1 m/s. Kod juniora kinetika v d je drugačija u početku. Povećanje od početne brzine 43 +- 0.1 m/s na 4.9 +- 01 m/s u rujnu izraženo je kasnije nego kod seniora, iako je trening bio sličan, ali za 15% manji po svom opsegu. Brzina je kasnije fluktuirala na toj razini do siječnja, kada je postigla najveće vrijednosti 5.0 +- 0.2 m/s. FS koju određuje kriterij defleksije, praktički se nije mijenjala kroz cijelo eksperimentalno razdoblje i fluktuirala na razini od 175 l/min, Brzina trčanja v d dovoljno je osjetljiva na promjene izdržljivosti, što je u saglasnosti s originalnim Conconijevim rezultatima. Slično je s brzinom trčanja kod 170 l/min i sa FS kod 4 m/s. Ostaje otvoreno pitanje značenja samog fenomena defleksije i FS d koja se ne mijenja iako dolazi do promjena izdržljivosti.The goal of this research has been to analyse the heart-rate changes (FS) in Conconi test, these changes being the consequence of endurance training in cross-country skiers. As we know, the endurance training reduces the heart-rate in conditions of the same load, but increases the running speed at the deflection threshold vd. So far, it has not been established how the heart-rate in this test changes during preparation stage of cross-country skiers, who apply three different types of load in their training: athletic running, roller and cross-country skiing, and it would be useful to know whether it is possible to use the Conconi test in order to assess the current fitness status of cross-country skiers. Seven trained cross-country skiers: 4 juniors and 3 seniors participated in the experiment in the period between June and January. Each of them has been tested by means of Conconi test once a month. The training in this period has significantly influenced and vd in seniors from 4.6 + 0.1 m/s in June to 4.9 + O01 m/s in September, and fluctuated at the same level till January, when vd increased to 5.2 + 0.1 m/s. In juniors the vd kinetics was initially different. The increase of the initial speed from 4.3 + 0.1 m/s up to 49 + 0.1 m/s in September is expressed later than in seniors, although their training sessions were very similar, the volume of the training of juniors being 15% smaller; vd fluctuated at this level till January when it reached its highest values of 5.0 + 0.2 m/s. The heart-rate, at the vd has practically not changed during the whole experimental period and fluctuated at the level of 175 l/min. Running speed vd is sensitive enough to changes of endurance, which is compatible with the original Conconi results. Predictors are the running speed at 170 l/min and the heart-rate at 4m/s. Still there is the question of the possible mechanisms of this very phenomenon and of the heart rate (FSd) which does not change, although there are changes in endurance.Das Ziel dieser Forschung war, die Herzfrequenzveränderungen (FS) beim Conconi Test zu analysieren, als Folge eines Ausdauertrainings bei den Skilangläufen. Es bekannt, daß das Ausdauertraining die Herzfrequenz bei derselben Belastung senkt, aber da es die Laufgeschwindigkeit bei der Ablenkungsschwelle vd erhöht. Es wurde bisher noch nicht festgestellt, wie sich die Herzfrequenz bei diesem Test in der Vorbereitung der Skilangläufern ändert, die während ihres Trainings drei Arten der Belastung abwechselnd anwenden: athletisches Laufen, den Rollschuh- und Skilanglauf. Es ist notwendig zu wissen, ob es möglich ist, den Conconi Test für die Beurteilung des gegenwärtigen Fitness-Status der Skilangläufer zu verwenden. Sieben trainierte Skilangläufer: 4 Junioren und 3 Senioren, haben in diesem Experiment im Zeitraum vom Juni bis Januar teilgenommen. Jeder von ihnen wurde einmal im Monat mit Conconi Test getestet. Das Training hat in diesem Zeitraum bedeutend die Laufgeschwindigkeit vd bei Senioren vom 4.6 + 0.1 m/s im Juni auf 4.9 + 0.1 m/s im September geändert. Die Laufgeschwindigkeit fluktuierte auf demselben Niveau bis Januar, wann sich die vd wieder auf 5.2 + 0.1 m/s erhöht hat. Am Anfang ist die Kinetik vd bei Junioren verschieden von der der Senioren. Die Erhöhung der Anfangsgeschwindigkeit vom 4.3 + 0.1 m/s auf 49 + 01 m/s im September ist später als bei Senioren zum Ausdruck gekommen, obwohl ihr Training dem Training der Senioren ähnelte, war aber um 15% bezüglich des Umfangs kleiner. Die Vd fluktuierte später auf demselben Niveau bis Januar, wann sie die höchsten Werte im Betrag von 5.0 + 0.2 m/s erreichte. Die Herzfrequenz, beim Vd hat sich praktisch während der ganzen Experimentzeit nicht geändert und fluktuierte auf dem Niveau von 175 l/min. Die Laufgeschwindigkeit vd ist genug veränderungsempfindlich, was kompatibel mit originellen Conconi Ergebnisse ist. Das Ähnliche geschieht mit der Laufgeschwindigkeit bei 170 l/min und mit der Herzfrequenz bei 4 m/s. Es bleibt die Frage der möglichen Mechanismen des Ablenkungsphänomens und der Herzfrequenz, die sich nicht ändert, obwohl es zu den Ausdauerveränderungen kommt
Photochemical and photobiological properties of 4,8-dimethyl-5′-acetylpsoralen
No full textThe photochemical and photobiological properties of 4,8-dimethyl-5'-acetylpsoralen (AcPso), proposed for the photochemotherapy of some skin diseases, were investigated. The photoreaction of AcPso with DNA is weaker in the presence of air than in a nitrogen atmosphere, in terms of total photobinding and DNA cross-linking; when UVA irradiation is performed in air, AcPso behaves as a monofunctional reagent. The quenching effect of oxygen is related to the high capacity of AcPso to produce singlet oxygen. Furthermore, it is demonstrated that AcPso photoadducts are better producers of singlet oxygen than free AcPso in solution. Using DNA sequencing methodology, two modes of DNA photo-sensitization by AcPso are shown, these lead to the formation of photoadducts mainly at T residues (and at C to a lesser extent) and to photo-oxidized G residues probably via singlet oxygen. Chemical or enzymatic cleavage were used as probes in these experiments. A rapid assay for the detection of the photodynamic effect of a photosensitizer on DNA, involving oxygen, is also described. Finally, the cytotoxicity and genotoxicity of AcPso on E. coli WP2 cells appear to be related to its ability to form photoadducts, in particular cross-links, rather than to its capacity to produce singlet oxygen
Transient monoclonal expansion of CD8+/CD57+ T-cell large granular lymphocytes after primary cytomegalovirus infection
No full textLymphocytosis associated with viral infection is generally polyclonal or oligoclonal. In this article, we describe a case of transient monoclonal CD8+/CD57+ T-cell lymphocytosis with large granular lymphocyte (LGL) morphology occurring after primary CMV infection and review cases of virus-associated monoclonal CD8+ T-cell expansions reported in the literature. Several clinical features shared by virus-associated monoclonal CD8+ T-cell expansions suggest the reactive nature of the lymphocytosis. Based on this, our case report and those reported in the literature support the notion that T-cell receptor clonality per se is not necessarily indicative of malignancy. These observations further corroborate the need for a close follow-up before assigning the diagnosis of LGL leukemia to individuals developing monoclonal CD8+ T-cell expansions
A First Dynamic Culture Approach to Engineer Tracheal Cartilage on Tubular Acellular Matrices via a Novel Bioreactor.
No full textBreast Cancer Cell Cultures on Electrospun Poly(ε-Caprolactone) as a Potential Tool for Preclinical Studies on Anticancer Treatments.
No full textDuring anticancer drug development, most compounds selected by in vitro screening are ineffective in in vivo studies and clinical trials due to the unreliability of two-dimensional (2D) in vitro cultures that are unable to mimic the cancer microenvironment. Herein, HCC1954 cell cultures on electrospun polycaprolactone (PCL) were characterized by morphological analysis, cell viability assays, histochemical staining, immunofluorescence, and RT-PCR. Our data showed that electrospun PCL allows the in vitro formation of cultures characterized by mucopolysaccharide production and increased cancer stem cell population. Moreover, PCL-based cultures were less sensitive to doxorubicin and electroporation/bleomycin than those grown on polystyrene plates. Collectively, our data indicate that PCL-based cultures may be promising tools for preclinical studies
Clinical Transplantation of a Tissue-Engineered Airway
No full texthttp://www.ventennalebioing.polimi.it/ Track 06_
Engineering the tumor environment in vitro using peptide-enriched, hyaluronic acid-based hydrogels
No full textElectrochemotherapy (ECT) is a clinically used and effective treatment in the care of melanoma, and recently it was suggested as a promising tool for the treatment of other deep-seated solid tumors (e.g., liver tumors). In general, ECT efficacy is evaluated in vitro on cell suspensions or in adhesion, and in vivo on animal models. Nevertheless, the first two mentioned approaches completely lack extracellular matrix (ECM) components, leading to unreliable results because they do not reflect the natural tissue architecture. To overcome this issue, several three-dimensional (3D) in vitro models, such as spheroids and hydrogel-based cultures, have been proposed to mimic the complex tumor microenvironment. In this frame, a new synthetic scaffold based on hyaluronic acid (HA) and self-assembling peptides (EAbuK) is proposed as an advantageous alternative. HA-EAbuK scaffolds promote spheroids formation where cells experiment cell-cell interactions, but also improve cell-ECM interactions. Liver cancer (HepG2) cell lines were cultured on HA and HA-EAbuK scaffolds and preliminary bioassays were carried out to assess cell viability and spheroids formation. Then, cells were electroporated at different electric field amplitudes. 3D cultures on HA scaffolds and cells in adhesion (2D cultures), electroporated using culture medium or phosphate-based EP buffer, were taken as controls. Our data showed that HepG2 cells cultured on HA-EAbuK scaffolds were already completely electroporated at 800 V/cm, whereas cells cultured on HA started to be electroporated at 1200 V/cm. In 2D cultures, HEPG2 cells were electroporated at 1000 V/cm and 1200 V/cm in EP buffer and in culture medium, respectively. Collectively, our preliminary results suggest that HepG2 cell cultures on HA-EAbuK hydrogels may represent a promising tool for in vitro evaluation of EP efficiency
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