Comparison of ex vivo and in vitro human fibroblast ageing models

Several studies have analyzed modulation of gene expression during physiological ageing with interesting, but often contradictory results, depending on the model used. In the present report we compare age-related metabolic and synthetic parameters in human dermal fibroblasts (HDF) isolated from young and old subjects (ex vivo ageing model) and cultured from early up to late cumulative population doublings (CPD) (in vitro ageing model) in order to distinguish changes induced in vivo by the aged environment and maintained in vitro, from those associated with cell senescence and progressive CPD. Results demonstrate that fibroblasts from aged donors, already at early CPD, exhibit an impaired redox balance, highlighting the importance of this parameter during ageing, even in the presence of standard environmental conditions, which are considered optimal for cell growth. By contrast, several proteins, as those related to heat shock response, or involved in endoplasmic reticulum and membrane trafficking, appeared differentially expressed only during in vitro ageing, suggesting that, at high CPD, the whole cell machinery becomes permanently altered. Finally, given the importance of the elastic component for a long-lasting connective tissue structural and functional compliance, this study focuses also on elastin and fibulin-5 synthesis and deposition, demonstrating a close relationship between fibulin-5 and ageing

Cytotoxic Evaluation of Elastomeric Dental Impression Materials on a Permanent Mouse Cell Line and on a Primary Human Gingival Fibroblast Culture

The need for clinically relevant in vitro tests of dental materials is widely recognized. Nearly all dental impression materials are introduced into the mouth just after mixing and allowed to set in contact with the oral tissues. Under these conditions, the materials may be toxic to cells or may sensitize the tissues. The aim of the present study is to evaluate the potential cytotoxicity of new preparations of elastomeric dental impression materials: A) four vinylpolysiloxanes: Elite H-D Putty and Elite H-D Light Body (Zhermack, Badia Polesine, Rovigo, Italy); Express Putty and Express Light Body (3M ESPE AG Seefeld, Germany) and B) two polyethers: Impregum Penta and Permadyne Penta L (3M ESPE AG Seefeld, Germany). The cytotoxicity of these impression materials were examined using two different cell lines: Balb/c 3T3 (permanent cell line) and human gingival fibroblasts (primary cell line) and their effects were studied by indirect and direct tests. The direct tests are performed by placing one sample of the impression materials in the centre of the Petri dishes at the time of the seeding of cells. The cell growth was evaluated at the 12th and 24th hours by cell number. The indirect tests were performed by incubating a square of 1 cm diameter impression material in 5 mL of medium at 37 °C for 24 hours (“eluates”). Subconfluent cultures are incubated with “eluates” for 24 hours. The MTT-formazan production is the method used for measuring the cell viability. The results indicate that: a) polyether materials are cytotoxic under both experimental conditions; b) among vinylpolysiloxanes, only Express Light Body (3M ESPE AG Seefeld, Germany) induces clear inhibition of cellular viability of Balb/c 3T3 evaluated by direct and indirect tests and c) the primary cell line is less sensitive to the toxic effect than the permanent cell line

The effect of serum withdrawal on the protein profile of quiescent human dermal fibroblasts in primary cell culture

The effect of serum deprivation on proliferating cells is well known, in contrast its role on primary cell cultures, at confluence, has not been deeply investigated. Therefore, in order to explore the response of quiescent cells to serum deprivation, ubiquitous mesenchymal cells, as normal human dermal fibroblasts, were grown, for 48 h after confluence, in the presence or absence of 10% FBS. Fibroblast behaviour (i.e. cell morphology, cell viability, ROS production and elastin synthesis) was evaluated morphologically and biochemically. Moreover, the protein profile was investigated by 2-DE and differentially expressed proteins were identified by MS. Serum withdrawal caused cell shrinkage but did not significantly modify the total cell number. ROS production, as evaluated by the dihydroethidium (DH2) probe, was increased after serum deprivation, whereas elastin synthesis, measured by a colorimetric method, was markedly reduced in the absence of serum. By proteome analysis, 41 proteins appeared to significantly change their expression, the great majority of protein changes were related to the cytoskeleton, the stress response and the glycolytic pathway. Data indicate that human dermal fibroblasts in primary cell culture can adapt themselves to environmental changes, without significantly altering cell viability, at least after a few days of treatment, even though serum withdrawal represents a stress condition capable to increase ROS production, to influence cell metabolism and to interfere with cell behaviour, favouring the expression of several age-related features

BIOCOMPATIBILITY OF COLLAGEN MEMBRANES ASSESSED BY CULTURING HUMAN J111 MACROPHAGES CELLS.

We have carried out an in vitro study on the interactions of human macrophages (J111) with two different membranes made of collagen type I and II, isolated from horse tendon and from horse articular and trachea cartilagene in order to obtain data on their biocompatibility. We have described the morphology of cell seeded on collagen films, and we have evaluated their proliferation as well as cytokine production as indicator of macrophage activation. The inflammatory response may in fact induce the destruction of collagen membranes and may interfere with cell and tissue behaviour. Results might be relevant for in vivo application such ad “tissue engeneering” and /or specialized cells implantation

Heparan sulfate affects elastin deposition in fibroblasts cultured from donors of different ages

Abstract Heparan sulfate (HS), due to its presence on the cell surface and in the extracellular milieu and its ability to modulate cell signaling, has a fundamental role in both physiological and pathological conditions. For decades we have demonstrated the occurrence of interactions between glycosaminoglycans (GAGs) and elastic fibers. In particular, we have recently shown that HS is present inside elastic fibers and plays a role in the assembly and stability of elastin coacervates. Elastin represents, within the extracellular matrix, the component most severely affected during aging, and changes in the synthesis and posttranslational modifications of HS have been described, possibly influencing cellular behavior and protein interactions. Thus, the present study has investigated, in two different in vitro experimental models, the role of HS on elastin deposition and assembly. Results demonstrate that: (1) Biological effects of HS are partly dependent on the physicochemical characteristics of the GAGs; (2) HS does not affect attachment, viability, and growth of human dermal fibroblasts; (3) HS does not modify elastin gene expression nor elastin synthesis, but favors α-elastin aggregation and, independently from the age of donors, elastin assembly; (4) HS significantly increases the expression of fibulin 5, and these effects are especially evident in fibroblasts isolated from aging donors. These data provide a better understanding of the biological role of HS and offer new perspectives regarding the possibility of restoring and/or preserving the elastic component with agin

Neonatal intensive care parent satisfaction: a multicenter study translating and validating the Italian EMPATHIC-N questionnaire

Background: In Neonatal Intensive Care Units (NICUs), parent satisfaction and their experiences are fundamental to assess clinical practice and improve the quality of care delivered to infants and parents. Recently, a specific instrument, the EMpowerment of PArents in THe Intensive Care-Neonatology (EMPATHIC-N), has been developed in the Netherlands. This instrument investigated different domains of care in NICUs from a family-centered care perspective. In Italy, no rigorous instruments are available to evaluate parent satisfaction and experiences in NICU with family-centered care. The aim of this study was to translate and validate the EMPATHIC-N instrument into Italian language measuring parent satisfaction. Methods: A psychometric study was conducted in nine Italian NICUs. The hospitals were allocated across Italy: four in the North, four in Central region, one in the South. Parents whose infants were discharged from the Units were enrolled. Parents whose infants died were excluded. Results: Back-forward translation was conducted. Twelve parents reviewed the instrument to assess the cultural adaptation; none of the items fell below the cut-off of 80% agreement. A total of 186 parents of infants who were discharged from nine NICUs were invited to participate and 162 parents responded and returned the questionnaire (87%). The mean scores of the individual items varied between 4.3 and 5.9. Confirmatory factor analysis was performed and all factor loadings were statistically significant with the exception of item ‘Our cultural background was taken into account’. The items related to overall satisfaction showed a higher trend with mean values of 5.8 and 5.9. The Cronbach’s alpha’s (at domain level 0.73-0.92) and corrected item-total scale correlations revealed high reliability estimates. Conclusions: The Italian EMPATHIC-N showed to be a valid and reliable instrument measuring parent satisfaction in NICUs from a family-centered care perspective. Indeed, it had good psychometric properties, validity, and reliability. Furthermore, this instrument is fundamental for further research and internationally benchmarking

STUDI SPERIMENTALI SUL MECCANISMO DELLA DISTROFIA DA MUTAZIONE A CARICO DEI GENI CODIFICANTI PER IL COLLAGENE VI

Mutations of genes coding for collagen VI are responsible, in humans, of congenital muscular dystrophies, giving rise to three syndromes Bethlem Myopathy (BM), Ullrich Congenital Muscular Dystrophy (UCMD) and Congenital Myosclerosis (CM). Based on the high degree of heterogeneity and the overlap between them, it has been proposed that these disorders may represent a clinical continuum rather than strictly separated entities, and that there may be a wider spectrum of collagen VI related disorders. Despite these major advances in understanding their genetic bases, the molecular pathogenesis remained partially obscure. As it is the case for many genetic diseases, creation of animal models may be the key to understand the physiopathology, and to devise and test potential therapies. Several years ago (Bonaldo at al, 1998) a mutant mouse with targeted inactivation of COL6A1 gene, coding for the 1(VI) chain, was created. In the absence of a 1(VI) chain, collagen VI does not assemble and is not secreted in the extracellular matrix, and therefore homozygous null mice (Col6a1-/-) completely lack collagen VI in their tissues. These mice are affected by early onset myopathic disease with weakness and histological alterations of skeletal muscles. Col6a1-/- muscle have loss of contractile strength with ultrastructural alterations of sarcoplasmic reticulum (SR) and mitochondria and spontaneous apoptosis. There is a latent mitochondrial dysfunction in myofibers which can be revealed upon incubation with the selective F1F0-ATPase inhibitor oligomycin, which causes mitochondrial depolarization, Ca2+ deregulation and increased apoptosis. These defects were reversible, as they can be normalized by plating Col6a1-/- myofibers on collagen VI or by addition of cyclosporin A (CsA), the inhibitor of mitochondrial permeability transition pore (PTP). Collagen VI myopathies, in mice and humans, can be effectively treated with drugs acting downstream on pathogenic lesion. These observations lead to the hypothesis that the lack of collagen VI causes an increased probability of opening of the PTP, but we don’t know through which signalling pathway the lack of collagen VI in the extracellular matrix can have effects on mitochondria. One important partner of collagen VI is the proteoglycan NG2. In particular, there is evidence that NG2 binds to collagen VI via a protein-protein interaction (Tillet et al, 1997). NG2 may be considered an important receptor mediating collagen VI-sarcolemma interactions and this relationship may be disrupted in the pathogenesis of Bethlem and Ullrich dystrophies. We also know that the perturbation of NG2 distribution on the cell surface results in parallel change in collagen VI distribution (Nishiyama et al,1997). The NG2-collagen VI interaction may be important for organization of the extracellular matrix, for binding of cells to the matrix, for determination of cell morphology in relation to the matrix, and for a transduction of transmembrane signalling. To clarify the relevance of NG2 for muscle function and structure, muscles of mice carrying a null mutation of NG2 were studied. The aim of this study was a comparative characterization (in vivo, ex vivo and in vitro) of the phenotype of muscles from ColVI-/- and NG2-/- mice and the evaluation of the differences between the two models to understand in what way the absence of these proteins might lead to mitochondrial damage. The experimental program was aimed to the characterization of muscles from C57BL/6, Col6a1-/- and NG2-/- mice in vivo, ex vivo ed in vitro. The integrity of the membrane was tested with the blue Evans dye which allows to detect, pointed out with blue color, muscle fibers in which the sarcolemma has been damaged. At first the analysis of functional parameters of muscle contraction was carried out in vivo, with the following tests: - mouse force (Grip test) - force developed by the muscle gastrocnemius during isometric contraction. Then the analysis of functional parameters was developed ex vivo: - intact muscle diaphragm, EDL, soleus dissected and analysed in myograph - electrophoresis of proteins from diaphragm, EDL, soleus - histological and histochemical analysis of gastrocnemius and tibial. Finally, single muscle fibres were kept in culture and studied, in vitro: - recording Ca2+ transient in single fibres of FDB - electrophoresis of single fibres - immunocytochemistry analyses. The results of all the above listed tests have shown that the two phenotypes have only a partial overlap and, thus, NG2 does not represent the only structural/functional connection between Collagen VI in the ECM and the intracellular processes in muscle fibres. The role of integrin require to be explored.Le mutazioni dei geni che codificano per le subunità del collagene VI sono una delle cause delle patologie muscolari ereditarie umane che si manifestano come la Miopatia di Bethlem (BM), la Distrofia Muscolare Congenita di Ullrich (UCMD) e la Miosclerosi Congenita (CM). Basandosi sull’alto grado di eterogeneità e di parziale sovrapposizione tra di loro, è stato proposto che questi disordini possano rappresentare un “continuum” clinico piuttosto che entità strettamente separate, e che ci possa essere un più ampio spettro di disordini connessi al collagene VI. Nonostante i grandi progressi nella comprensione delle loro basi genetiche, la patogenesi molecolare rimane ancora in parte sconosciuta. Come nel caso di molti difetti genetici, la creazione di animali transgenici può essere la chiave per comprendere la fisiopatologia e per mettere a punto, e testare, potenziali terapie. Molti anni fa (Bonaldo et al, 1998) è stato creato un topo mutante con inattivazione mirata del gene COL6A1, che codifica per la catena 1(VI). In assenza della catena 1(VI), il collagene non è assemblato e non è secreto nella matrice extracellulare, e pertanto il topo omozigote mutante (Col6a1-/-) perde il collagene VI nei suoi tessuti. I topi sono affetti da un disordine miopatico ad esordio precoce con debolezza e cambiamenti istologici del muscolo scheletrico. I muscoli del Col6a1-/- perdono forza contrattile e mostrano alterazioni ultrastrutturali a livello del reticolo sarcoplasmatico (SR), dei mitocondri e apoptosi spontanea. E’ presente una disfunzione mitocondriale latente nelle miofibre che si può evidenziare con incubazione con oligomicina, inibitore della F1F0-ATPasi, che causa depolarizzazione mitocondriale, de-regolazione del Ca2+ e aumento dell’apoptosi. Questi difetti sono reversibili, e possono essere normalizzati piastrando le fibre muscolari di Col6a1-/- su collagene VI o somministrando cisclosporina A (CsA), un inibitore del poro di transizione di permeabilità mitocondriale (PTP). Le miopatie dovute al collagene VI, sia umane che negli animali, possono essere efficacemente trattate con tale farmaco che agisce a valle della lesione patogenetica (Irwin et al, 2003 e Merlini et al, 2008). Così queste osservazioni portano ad ipotizzare che la mancanza del collagene VI causa un aumento dell’apertura del PTP ma non è ancora noto per mezzo di quale via di segnale. Un importante partner del collagene VI è il proteoglicano NG2. In particolare, ci sono prove che NG2 si leghi al collagene VI attraverso un interazione proteina-proteina (Tillet et al, 1997). NG2 può essere considerato un importante mediatore dell’interazione collagene VI-sarcolemma e il venir meno di questa relazione potrebbe avere un ruolo nella patogenesi delle distrofie di Bethlem e Ullrich. Sappiamo inoltre che modificazioni nella distribuzione superficiale di NG2 porta ad un parallelo cambiamento nella distribuzione del collagene VI (Nishiyama et al,1997). L’interazione NG2-collagene VI può essere importante nell’organizzazione della matrice, per il legame delle cellule alla matrice, per determinare la morfologia cellulare in risposta alla matrice, e per la trasduzione del segnale transmembrana. Per chiarire l’importanza di NG2 per la funzione e la struttura muscolare, sono stati studiati muscoli di topi con mutazione di NG2. Lo scopo dello studio è la caratterizzazione fenotipica comparativa (in vivo, ex vivo and in vitro) di Col6a1-/- and NG2-/- e la valutazione delle differenze tra i due modelli per comprendere se la mancanza di queste proteine porti ad un simile danno nella fibra muscolare. Si è proceduto dapprima a saggiare l’integrità della membrana con il colorante vitale blue Evans che permette di rilevare, evidenziandole con colorazione blu, le fibre muscolari il cui sarcolemma ha subito un danno. Poi, si è passati quindi all’analisi dei parametri funzionali della contrazione muscolare in vivo quali: - sviluppo di forza (Grip test) - sviluppo della forza massimale del gastrocnemio stimolato per via nervosa. Successivamente è stata effettuata una valutazione ex vivo: - meccanica dei muscoli interi diaframma, EDL e soleo - elettroforesi delle proteine muscolari - analisi istochimiche di gastrocnemio e tibiale. Infine per avere un quadro completo si è continuata l’ indagine in vitro : - transienti di calcio su singole fibre di FDB - elettroforesi su singole fibre di FDB - analisi immunocitochimiche. I risultati di tali analisi hanno mostrato che i due fenotipi hanno solamente una parziale sovrapposizione e quindi NG2 non rappresenta l’unica via di mediazione della presenza del collagene VI. Il ruolo delle integrine richiede di essere esplorato