328 research outputs found
MRI biomarkers of disease evolution and efficacy of stem cell therapy in the SOD1(G93A) experimental model of Amyotrophic Lateral Sclerosis
No full textLa Sclerosi Laterale Amiotrofica (SLA) è una malattia neurodegenerativa mortale che colpisce i motoneuroni superiori nella corteccia motoria e i motoneuroni inferiori nel tronco cerebrale e del midollo spinale.La diagnosi di SLA rimane ancora oggi una diagnosi ad esclusione di altre patologie perché non vi sono segni clinici patognomonici, soprattutto all’ esordio, nè test diagnostici specifici. La diagnosi viene quindi formulata dopo un’ accurato esame neurologico alla ricerca di segni di lesione, ma sarà poi solo la progressione della malattia e la comparsa di nuovi segni che confermerà la diagnosi nel tempo. Nella SLA, l'assenza di marcatori specifici per la malattia comporta un ritardo tra la comparsa della malattia e la diagnosi che può variare tra i 13 ei 18 mesi, precludendo un inizio precoce dei trattamenti neuroprotettivi.La scoperta delle mutazioni SOD1 legate alla SLA di origine eraditaria ha permesso di sviluppare modelli eziologici per la malattia. Grazie al modello animale SOD1(G93A), modalità di neuroimaging, tra cui la Risonanza Manetica (RM), possono essere utilizzate per identificare potenziali biomarcatori della patologia.Questo progetto di dottorato è diviso in due sezioni sperimentali.La prima parte del progetto ha l'obiettivo di identificare e validare biomarcatori RM in un modello sperimentale di SLA (topi SOD1(G93A)) durante la progressione della malattia e, sucessivamente, di monitorare l'efficacia di una terapia basata sulle cellule staminali.Studi recenti hanno suggerito che la malattia potrebbe iniziare nel muscolo scheletrico, piuttosto che nei motoneuroni. Per questo motivo, il nostro protocollo RM si focalizza sia sul cervello, che sugli arti posteriori degli animali; le immagini RM sono state acquisite a punti temporali corrispondenti al decorso della malattia (fase preclinica, insorgenza e la fase terminale). Immagini T2-pesate, mappe del T2 e le successive analisi con la tecnica Voxel Based Morphometry, hanno mostrato lesioni del tronco cerebrale nei topi a partire dalla comparsa della malattia. L’analisi RM degli arti posteriori ha riportato: riduzione del volume muscolare, alterazione dei parametri DTI (FA, MD e RD) e variazione nel rapporto tra intensità del segnale del muscolo e intensità del segnale del grasso.Testando l'efficacia di una terapia innovativa, attraverso l'evoluzione dei biomarker precedentemente definiti, abbiamo confermato l'efficacia della terapia cellulare nel rallentare il decorso clinico nel modello animale SOD1(G93A).Tuttavia, studi recenti hanno riportato che la maggior parte degli effetti terapeutici delle cellule staminali sono probabilmente duvuti a fattori solubili rilasciati in nanovescicole (esosomi). Per capire meglio come e dove gli esosomi esplicano il loro effetto terapeutico, si ha bisogno comprendere il loro meccanismo d’ azione e i loro bersagli molecolari/cellulari. La RM può essere utilizzata come metodo non invasivo per la visualizzazione degli esosomi e può fornire informzioni su dove gli esosomi esercitano la loro azione neuroportettiva.Nella seconda parte del progetto, noi proponiamo un nuovo approccio per marcare gli esosomi con nanoparticelle di ossido di ferro (USPIO), permettendo la loro individuazione attraverso immagini RM. Inoltre, questo nuovo metodo di labeling preserva le caratteristiche morfologiche e fisiologiche degli esosomi. In particolare, abbiamo dimostrato che marcando le cellule staminali con le USPIO prima dell’ estrazione degli esosomi, questi, una volta isolati, trattengono le nanoparticelle e possono essere visualizzati tramite RM, sia in vitro che in vivo.Amyotrophic lateral sclerosis (ALS) is fatal neurodegenerative disorder affecting upper motor neurons in the motor cortex as well as lower motor neurons in the brain stem and spinal cord. In ALS, the absence of a disease marker has a negative consequence: the delay from onset of the disease to diagnosis can vary between 13 and 18 months precluding early initiation of neuroprotective treatments. The capability of Magnetic Resonance Imaging (MRI) in diagnosis of ALS has been recently addressed. The accessible, non-invasive and radiation-free characteristics of MRI make this technique highly practical as a biomarker tool. MRI has been used in ALS patients, but not during the pre-clinical phase, a stage currently inaccessible for human study in what is largely a sporadic disease. The discovery of SOD1 mutations linked with familial ALS has made it possible to develop aetiological models for ALS. Thanks to the SOD1(G93A) animal model, neuroimaging modalities can be used to identify potential biomarkers. This PhD project is divided in two experimental sections.The first section aimed to identify and validate MRI biomarkers in SOD1(G93A) animal model along the disease progression and to monitor the efficacy of stem cells-based therapy. Recent studies have suggested that the disease could initiate in skeletal muscle, rather than in the motor neurons. For this reason, our MRI protocol focused on brain and hind limb and SOD1(G93A) mice were scanned at time point corresponding to disease evolution (preclinical stage, onset and terminal stage). T2-weighted images, T2 map and the subsequent analysis with Voxel Based Morphometry technique, showed brainstem lesions in mice starting from the onset of the disease. In hind limb of SOD1(G93A) we found reduced muscular volume, alteration in Diffusion Tensor Imaging parameters (FA, MD and RD) and in muscle/fat signal intensity ratio. Testing the efficacy of innovative therapy, through the evolution of the previously defined biomarkers, we confirmed the efficacy of stem cells therapy in slowing down the clinical course in the SOD1(G93A) animal model.However, recent studies reported that most biological effects of stem cells are probably mediated by soluble factors released in nanovescicles (exosomes) which influence the surrounding cells. To better understand the action mechanisms and the molecular/cellular target of exosomes, we need elucidation of where exosomes explicate their therapeutic effect. In particular, MRI can be used as a noninvasive method for tracking exosomes in vivo and it can provide information about where exosomes exert their neuroprotective action. In the second section we propose a new approach to label exosomes with iron oxide nanoparticles that allows their detection by MRI preserving their morphology and physiological characteristic. In particular, we showed that by labeling stem cells with ultra-small superparamagnetic iron oxide nanoparticles before nanovesicles extraction, the isolated exosomes retain nanoparticles and can be visualized by MRI both in in vitro and in vivo condition
On the coordination chemistry of the lanthanum(III) nitrate salt in EAN/MeOH mixtures
No full textA thorough structural characterization of the La(NO3)3 salt dissolved into several mixtures of ethyl ammonium nitrate (EAN) and methanol (MeOH) with EAN molar fraction χEAN ranging from 0 to 1 has been carried out by combining molecular dynamics (MD) and X-ray absorption spectroscopy (XAS). The XAS and MD results show that changes take place in the La3+ first solvation shell when moving from pure MeOH to pure EAN. With increasing the ionic liquid content of the mixture, the La3+ first-shell complex progressively loses MeOH molecules to accommodate more and more nitrate anions. Except in pure EAN, the La3+ ion is always able to coordinate both MeOH and nitrate anions, with a ratio between the two ligands that changes continuously in the entire concentration range. When moving from pure MeOH to pure EAN, the La3+ first solvation shell passes from a 10-fold bicapped square antiprism geometry where all the nitrate anions act only as monodentate ligands to a 12-coordinated icosahedral structure in pure EAN where the nitrate anions bind the La3+ cation both in mono- and bidentate modes. The La3+ solvation structure formed in the MeOH/EAN mixtures shows a great adaptability to changes in the composition, allowing the system to reach the ideal compromise among all of the different interactions that take place into it
Direct Observation of Contact Ion-Pair Formation in La(3+) Methanol Solution
No full text[Image: see text] An approach combining molecular dynamics (MD) simulations and X-ray absorption spectroscopy (XAS) has been used to carry out a comparative study about the solvation properties of dilute La(NO(3))(3) solutions in water and methanol, with the aim of elucidating the still elusive coordination of the La(3+) ion in the latter medium. The comparison between these two systems enlightened a different behavior of the nitrate counterions in the two environments: while in water the La(NO(3))(3) salt is fully dissociated and the La(3+) ion is coordinated by water molecules only, the nitrate anions are able to enter the metal first solvation shell to form inner-sphere complexes in methanol solution. The speciation of the formed complexes showed that the 10-fold coordination is preferential in methanol solution, where the nitrate anions coordinate the La(3+) cations in a monodentate fashion and the methanol molecules complete the solvation shell to form an overall bicapped square antiprism geometry. This is at variance with the aqueous solution where a more balanced situation is observed between the 9- and 10-fold coordination. An experimental confirmation of the MD results was obtained by La K-edge XAS measurements carried out on 0.1 M La(NO(3))(3) solutions in the two solvents, showing the distinct presence of the nitrate counterions in the La(3+) ion first solvation sphere of the methanol solution. The analysis of the extended X-ray absorption fine structure (EXAFS) part of the absorption spectrum collected on the methanol solution was carried out starting from the MD results and confirmed the structural arrangement observed by the simulations
MITOMYCIN C MODULATION OF CORNEAL WOUND HEALING AFTER PHOTOREFRACTIVE KERATECTOMY IN HIGHLY MYOPIC EYES
No full textOphthalmology. 2005 Feb;112(2):208-18; discussion 219.
Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes.
Gambato C, Ghirlando A, Moretto E, Busato F, Midena E.
SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy.
Abstract
PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes.
DESIGN: Prospective, double-masked, randomized clinical trial.
PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia.
METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months).
MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH.
RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively).
CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK.
Comment in
Ophthalmology. 2006 Feb;113(2):357; author reply 357-8.
PMID: 15691552 [PubMed - indexed for MEDLINE
Comparative technical analysis of lipoaspirate mechanical processing devices
No full textFat grafting is a well-established procedure in reconstructive, aesthetic, and regenerative medicine, in particular due to the presence in the adipose tissue of a high concentration of mesenchymal stem cells. The need to reduce fat processing times, for an immediate clinical use and regulatory restrictions on the degree of manipulation of human tissues have led to the development of numerous devices for the mechanical, non-enzymatic processing of adipose tissue. The aim of this study is to describe the state of the art of mechanical devices used for fat processing, performing a technical analysis of the currently commercially available devices. This should facilitate the development of new devices that improve therapeutic results
Imaging the pH evolution of an acute kidney injury model by means of iopamidol, a MRI-CEST pH-responsive contrast agent.
No full textPurpose To investigate in vivo possible pH level alterations following an acute renal failure disease using a MRI-CEST pH responsive contrast agent. The impact of functional evolution in different renal compartments over time was also investigated. Methods a mouse model of acute kidney injury was obtained by glycerol-induced rhabdomyolysis. pH maps were obtained using Iopamidol (0.75 g iodine/kg b.w. corresponding to 2.0 mmol/kg) in a control group (n = 3) and in the acute kidney injury group (n = 6) at 1, 3, 7, 14, and 21 days after the damage induction at 7T. Histology assessment of renal damage and blood urea nitrogen levels were compared with pH maps. Results during the acute kidney injury, there was a robust increase of pH values, which peaked after 3 days, compared with the predamage situation. In addition, it was possible to detect changes in contrast detection between the different functional regions of the damaged kidneys. Moreover, a slow restoration of normal pH values was observed three weeks after the glycerol injection. Conclusions pH appears to be a good parameter to assess the early detection of kidney injury as well as it acts as a reporter of the recovery toward the physiologic functionality
Heterogeneous enhancement pattern in DCE-MRI reveals the morphology of normal lymph nodes: an experimental study
No full textPurpose: To investigate the heterogeneous enhancement pattern in normal lymph nodes of healthy mice by different albumin-binding contrast agents. Methods: The enhancement of normal lymph nodes was assessed in mice by dynamic contrast-enhanced MRI (DCE-MRI) after the administration of two contrast agents characterized by different albumin-binding properties: gadopentetate dimeglumine (Gd-DTPA) and gadobenate dimeglumine (Gd-BOPTA). To take into account potential heterogeneities of the contrast uptake in the lymph nodes, k-means cluster analysis was performed on DCE-MRI data. Cluster spatial distribution was visually assessed. Statistical comparison among clusters and contrast agents was performed on semiquantitative parameters (AUC, wash-in rate, and wash-out rate) and on the relative size of the segmented clusters. Results: Cluster analysis of DCE-MRI data revealed at least two main clusters, localized in the outer portion and in the inner portion of each lymph node. With both contrast agents, AUC (p < 0.01) and wash-in (p < 0.05) rates were greater in the inner cluster, which also showed a steeper wash-out rate than the outer cluster (Gd-BOPTA, p < 0.01; Gd-DTPA, p=0.056). The size of the outer cluster was greater than that of the inner cluster by Gd-DTPA (p < 0.05) and Gd-BOPTA (p < 0.01). The enhancement pattern of Gd-DTPA was not significantly different from the enhancement pattern of Gd-BOPTA. Conclusion: DCE-MRI in normal lymph nodes shows a characteristic heterogeneous pattern, discriminating the periphery and the central portion of the lymph nodes. Such a pattern deserves to be investigated as a diagnostic marker for lymph node staging
In vivo imaging techniques: a new era for histochemical analysis
No full textIn vivo imaging techniques can be integrated with classical histochemistry to create an actual histochemistry of water. In particular, Magnetic Resonance Imaging (MRI), an imaging technique primarily used as diagnostic tool in clinical/preclinical research, has excellent anatomical resolution, unlimited penetration depth and intrinsic soft tissue contrast. Thanks to the technological development, MRI is not only capable to provide morphological information but also and more interestingly functional, biophysical and molecular. In this paper we describe the main features of several advanced imaging techniques, such as MRI microscopy, Magnetic Resonance Spectroscopy, functional MRI, Diffusion Tensor Imaging and MRI with contrast agent as a useful support to classical histochemistry.</p
MRI reveals therapeutical efficacy of stem cells: an experimental study on the SOD1(G93A) animal model
No full textPURPOSE: The first part of the experiment identifies and validates MRI biomarkers distinctive of the disease progression in the transgenic superoxide dismutase gene (SOD1(G93A)) animal model. The second part assesses the efficacy of a mesenchymal stem cell-based therapy through the MRI biomarkers previously defined. METHODS: The first part identifies MRI differences between SOD1(G93A) and healthy mice. The second part of the experiment follows the disease evolution of stem cell-treated and non-stem-cell treated SOD1(G93A) mice. The analysis focused on voxel-based morphometry and T2 mapping on the brain tissues, and T2-weighted imaging and diffusion tensor imaging (DTI) on the hind limbs. RESULTS: Comparing diseased mice to healthy control revealed gray matter alterations in the brainstem area, accompanied by increased T2 relaxation time. Differences in muscle volume, muscle signal intensity, fractional anisotropy, axial diffusivity, and radial diffusivity were measured in the hind limbs. In the comparison between stem cell-treated mice and nontreated ones, differences in muscle volume, muscle signal intensity, and DTI-derived maps were found. CONCLUSION: MRI-derived biomarkers can be used to identify differences between stem cell-treated and nontreated SOD1(G93A) mice. Magn Reson Med, 2017. © 2017 International Society for Magnetic Resonance in Medicine
EXPLORING ADIPOSE-DERIVED STEM CELLS IN REGENERATIVE MEDICINE: INNOVATIVE APPROACHES OF EXTRACTION, STIMULATION, AND IN VIVO APPLICATION WITH A FOCUS ON NEURONAL POTENTIAL
No full textThis doctoral thesis comprises seven chapters that explore the intricate world of adipose-derived stem cells (ADSCs) and their regenerative potential. Chapter 1 presents an in-depth analysis of the anatomical aspects of adipose tissue and the skin, along with various morphological techniques essential for studying this complex biological entity. We focused the research on the gluteal region, recognized for its abundant adipose tissue content, and the face, marked for its exceptional diversity and complexity. Chapter 2 is dedicated to conceptualizing the regenerative potential of ADSCs, describing comprehensive insights garnered from a book chapter and an extensive review. Chapter 3 explores novel enzymatic and mechanical methods for obtaining highly regenerative stromal vascular fractions enriched with stem cells, opening new frontiers in regenerative medicine. Chapter 4 focuses on diverse methods to stimulate ADSCs, highlighting research on the impact of acoustic wave therapy and hyaluronic acid on modulating the behavior and functionality of these specialized cells. The 5th chapter delves into in vivo regenerative applications of stem cell-rich stromal vascular fraction in a calvaria mouse model, to investigate their potential in bone regeneration. Chapter 6 elucidates the neuronal potential of mesenchymal stem cells, with special emphasis on enhancing neurogenesis through the application of hyaluronic acid and comparative assessments of the neuronal differentiation ability in different stem cell sources. Lastly, Chapter 7 serves as an extension, encompassing diverse research publications in the field of cancer research and reconstructive medicine, broadening the scope and impact of the thesis findings. Through these meticulously structured chapters, this thesis not only advances our understanding of ADSCs and their regenerative properties but also highlights their promising applications across various fields of medicine, laying a solid foundation for future applications
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