Littérature scientifique sur le sujet « Patologia ginocchio »

The use of scaffolds for Tissue Engineering (TE) is increasing due to their efficacy in helping the body rebuild damaged or diseased tissue. Hydroxyapatite (HA) is the most suitable bioactive ceramic to be used in orthopaedic reconstruction since it replicates the mineral component of the hard tissues, and it has therefore excellent biocompatibility properties. The temporal and spatial control of the tissue regeneration process is the limit to be overcome in order to treat large bone and osteochondral defects. In this thesis we describe the realization of a magnetic scaffolds able to attract and take up growth factors or other bio-agents in vivo via a driving magnetic force. This concept involves the use of magnetic nanoparticles (MNP) functionalized with selected growth factors or stem cells. These functionalized MNP act as shuttles transporting the bio-agents towards and inside the scaffold under the effect of the magnetic field, enhancing the control of tissue regeneration processes. This scaffold can be imagined as a fixed “station” that provides a unique possibility to adjust the scaffold activity to the specific needs of the healing tissue. Synthetic bone graft substitutes, made of collagen or biomineralized collagen (i.e. biomimetic Hydroxyapatite/collagen composites) were used as starting materials for the fabrication of magnetic scaffolds. These materials are routinely used clinically to replace damaged or diseased cartilaginous or bone tissue. Our magnetization technique is based on a dip-coating process consisting in the infilling of biologically inspired porous scaffolds with aqueous biocompatible ferrofluids’ suspensions. In this technique, the specific interconnected porosity of the scaffolds allows the ferrofluids to be drawn inside the structure by capillarity. A subsequent freeze-drying process allows the solvent elimination while keeping very nearly the original shape and porosity of the scaffolds. The remaining magnetic nanoparticles, which are trapped in the structure, lead to the magnetization of the HA/Collagen scaffold. We demonstrate here the possibility to magnetize commercially available scaffolds up to magnetization values that are used in drug delivery processes. The preliminary biocompatibility test showed that the investigated scaffolds provide a suitable micro-environment for cells. The biocompatibility of scaffold facilitates the growth and proliferation of osteogenic cells.

The use of scaffolds for Tissue Engineering (TE) is increasing due to their efficacy in helping the body rebuild damaged or diseased tissue. Hydroxyapatite (HA) is the most suitable bioactive ceramic to be used in orthopaedic reconstruction since it replicates the mineral component of the hard tissues, and it has therefore excellent biocompatibility properties. The temporal and spatial control of the tissue regeneration process is the limit to be overcome in order to treat large bone and osteochondral defects. In this thesis we describe the realization of a magnetic scaffolds able to attract and take up growth factors or other bio-agents in vivo via a driving magnetic force. This concept involves the use of magnetic nanoparticles (MNP) functionalized with selected growth factors or stem cells. These functionalized MNP act as shuttles transporting the bio-agents towards and inside the scaffold under the effect of the magnetic field, enhancing the control of tissue regeneration processes. This scaffold can be imagined as a fixed “station” that provides a unique possibility to adjust the scaffold activity to the specific needs of the healing tissue. Synthetic bone graft substitutes, made of collagen or biomineralized collagen (i.e. biomimetic Hydroxyapatite/collagen composites) were used as starting materials for the fabrication of magnetic scaffolds. These materials are routinely used clinically to replace damaged or diseased cartilaginous or bone tissue. Our magnetization technique is based on a dip-coating process consisting in the infilling of biologically inspired porous scaffolds with aqueous biocompatible ferrofluids’ suspensions. In this technique, the specific interconnected porosity of the scaffolds allows the ferrofluids to be drawn inside the structure by capillarity. A subsequent freeze-drying process allows the solvent elimination while keeping very nearly the original shape and porosity of the scaffolds. The remaining magnetic nanoparticles, which are trapped in the structure, lead to the magnetization of the HA/Collagen scaffold. We demonstrate here the possibility to magnetize commercially available scaffolds up to magnetization values that are used in drug delivery processes. The preliminary biocompatibility test showed that the investigated scaffolds provide a suitable micro-environment for cells. The biocompatibility of scaffold facilitates the growth and proliferation of osteogenic cells.

Introduzione. Col progredire dell’età, la capacità dell’organismo di modificare struttura e funzione di organi e apparati in risposta agli stimoli si modifica. Scopo di questo progetto è indagare l’effetto dell’età sul rimodellamento cardiovascolare in risposta all’allenamento aerobico e valutare gli effetti della corsa sulla patologia del ginocchio. Metodi. 237 volontari sani, sedentari, sono stati valutati al basale e dopo 6 mesi di allenamento non supervisionato e il completamento della loro prima maratona, con: 1) risonanza magnetica cardiaca a 1.5T; 2) misurazione non invasiva della pressione arteriosa (PA) centrale e brachiale; 3) risonanza magnetica (MRI) bilaterale del ginocchio a 3.0T. La “età aortica biologica” è stata calcolata al basale dalla relazione tra l’età anagrafica e la rigidità arteriosa. Modificazioni nella rigidità arteriosa sono state valutate a livello dell’aorta ascendente (Ao-A), discendente (Ao-D), della biforcazione polmonare (Ao-P) e del passaggio diaframmatico (Ao-D).Per l’analisi, i soggetti sono stati divisi in due gruppi in base all’età (≥35 anni: O35; 34 anni: U35). Risultati. Le percentuali di infortunio e completamento della corsa sono state simili nei due gruppi. 138 corridori (U35: n =71, femmine =49%; O35: n =67, femmine =51%) hanno completato la corsa. In media, gli U35 sono stati 37 minuti più veloci (12%). L’allenamento si è associato a un piccolo incremento nella massa del ventricolo sinistro (LV) in entrambi i gruppi (3g/m2, p <0.001), ma negli U35 si è osservato anche un aumento del volume biventricolare (volume telediastolico LV [EDV]i +3%; volume telesistolico LV [ESV]i +8%; EDVi del ventricolo destro [RV] +4%, RVESVi +5%; p<0.01 per tutti). La compliance sistemica aortica si è ridotta nell’intero campione del 7% (p=0.020) e, in particolare negli O35, anche le resistenze vascolari sistemiche (-4% nell’intero campione, p=0.04) e la PA (sistolica/diastolica, intero campione: brachiale -4/-3 mmHg, centrale -4/-2 mmHg, tutti p <0.001; O35: brachiale -6/-3 mmHg, centrale -6/-4 mmHg, tutti p<0.001). Al basale, una decade di età anagrafica corrispondeva a una riduzione della distensibilità Ao-A, Ao-P, e Ao-D di 2.3, 1.9, and 3.1 x 10-3 mm Hg-1 rispettivamente (p < 0.05 per tutti). La distensibilità di Ao-D è aumentata (Ao-P: 9%; p = 0.009; Ao-D: 16%; p = 0.002), mentre quella di Ao-A è rimasta invariata. Queste variazioni corrispondono a una riduzione nella “età aortica” di 3.9 anni (95% CI: da 1.1 a 7.6 anni) e 4.0 anni (95% CI: da 1.7 a 8.0 years) (Ao-P e Ao-D, rispettivamente). Il beneficio è stato maggiore in partecipanti di sesso maschile, più anziani e più lenti (p < 0.05 per tutti). La MRI basale ha mostrato segni di danno asintomatico in numerose strutture del ginocchio nella maggioranza degli 82 soggetti esaminati. Dopo la maratona, la MRI ha mostrato una riduzione del punteggio di danno nell’edema midollare subcondrale nei condili tibiali (p=0.011) e femorali (p=0.082). Conclusioni. In soggetti sani e sedentari, un allenamento fisico non supervisionato, di intensità lieve e di media durata induce variazioni misurabili nella struttura e funzione cardiovascolare. L’entità di queste variazioni è dipendente dall’età, con maggior rimodellamento cardiaco osservato nei più giovani e maggior rimodellamento vascolare osservato nei più anziani, fino a una riduzione della PA centrale e rigidità arteriosa equivalenti a una riduzione di ~ 4 anni nell’età vascolare. Inoltre, l’allenamento e corsa di una maratona non sono lesivi sull’articolazione del ginocchio.
Background. Healthy ageing is associated with changes in human’s body ability to modify organs and systems structure and function in response to stimuli. With this project we sought to understand whether remodelling in response to a stimulus, exercise training, altered with healthy ageing and to deepen the knowledge about running effects on the knee joint. Methods. 237 untrained healthy male and female subjects volunteering for their first-time marathon were recruited. At baseline and after 6 months of unsupervised training, race completers underwent tests including 1.5T cardiac magnetic resonance, brachial and non-invasive central blood pressure (BP) assessment and a 3.0T bilateral knee magnetic resonance. Biological “aortic age” was calculated from the baseline chronological age-stiffness relationship. Change in stiffness was assessed at the ascending (Ao-A) and descending aorta at the pulmonary artery bifurcation (Ao-P) and diaphragm (Ao-D). For analysis, runners were divided by age (O35: ≥35y.o.; U35:  34y.o.) Results. Injury and completion rates were similar among groups. 138 runners (under 35 [U35]: n=71, females=49%; over 35 [O35]: n=67, females=51%) completed the race. On average, U35 were faster by 37 minutes (12%). Training induced a small increase in left ventricle (LV) mass in both groups (3g/m2, p<0.001), but U35 also increased ventricular cavity sizes (LV end-diastolic volume [EDV]i +3%; LV end-systolic volume [ESV]i +8%; right ventricle [RV] EDVi +4%, RVESVi +5%; p<0.01 for all). Systemic aortic compliance fell in the whole sample by 7% (p=0.020) and, especially in O35, also systemic vascular resistance (-4% in the whole sample, p=0.04) and blood pressure (systolic/diastolic, whole sample: brachial -4/-3 mmHg, central -4/-2 mmHg, all p <0.001; O35: brachial -6/-3 mmHg, central -6/-4 mmHg, all p<0.001). At baseline, a decade of chronological ageing correlated with a decrease in Ao-A, Ao-P, and Ao-D distensibility by 2.3, 1.9, and 3.1 x 10-3 mm Hg-1, respectively (p < 0.05 for all). Descending aortic distensibility increased (Ao-P: 9%; p = 0.009; Ao-D: 16%; p = 0.002), while remaining unchanged in the Ao-A. These translated to a reduction in “aortic age” by 3.9 years (95% CI: 1.1 to 7.6 years) and 4.0 years (95% CI: 1.7 to 8.0 years) (Ao-P and Ao-D, respectively). The benefit was greater in older, male participants with slower running times (p < 0.05 for all). Pre marathon and pretraining MRI showed signs of damage, without symptoms, to several knee structures in the majority of the 82 middle-aged volunteers. However, after the marathon, MRI showed a reduction in the radiological score of damage in subchondral bone marrow oedema in the condyles of the tibia (p=0.011) and femur (p=0.082). Conclusion. Medium-term, unsupervised, mild intensity physical training in healthy sedentary individuals induces measurable remodelling of both heart and vasculature. This amount is age-dependent, with predominant cardiac remodelling when younger and predominant vascular when older, with a reduction in central blood pressure and aortic stiffness equivalent to a ~ 4-year reduction in vascular age. Training for and running a marathon is associated with improvement in the condition of bone marrow and articular cartilage.