Células madre : ¿la panacea de la medicina del siglo XXI?

Hemos oído hablar mucho de ellas últimamente. Muchos han puesto en ella su esperanza. Las hay embrionarias, adultas, inducidas e incluso híbridas. Pero ¿qué son y para qué pueden servir este tipo de células

A single-point mutation in FGFR2 affects cell cycle and Tgfβ signalling in osteoblasts

AbstractFgf and Tgfβ are key regulators of bone development. It is not known, however, whether there is a relationship between defective Fgf signalling, resulting in a premature cranial suture fusion, and Tgfβ signalling. We used mouse calvaria osteoblasts carrying a mutation (hFGFR2-C278F) associated with Crouzon and Pfeiffer syndromes to investigate effects of this mutation on cell growth and possible mechanisms underlying it. Mutated osteoblasts displayed reduced S-phase, increased apoptosis and increased differentiation. As Tgfβ signalling appeared to be required in an autocrine/paracrine manner for osteoblast proliferation, we tested the hypothesis that reduced growth might be due, at least in part, to an altered balance between FGF and Tgfβ signalling. Tgfβ expression was indeed decreased in mutated osteoblasts, as compared to osteoblasts carrying the wild type hFGFR2. Treatment with Tgfβ, however, neither increased proliferation in mutated osteoblasts, unlike in controls, nor rescued proliferation in control osteoblasts treated with an Erk1/2 inhibitor. Significantly, Erk2, that is important for proliferation, was reduced relatively to Erk1 in mutated cells. Altogether this study suggests that the hFGFR2-C278F mutation affects the osteoblast ability to respond to Tgfβ stimulation via the Erk pathway and that the overall effect of the mutation is a loss of function

Bone marrow-derived mesenchymal stem cells characterization and transplantation in an animal model of congenital hydrocephalus

Congenital hydrocephalus is a disorder presenting a degeneration of the periventricular cerebral parenchyma and the white matter, which causes significant mortality and life-long neurological complications. There are currently no effective therapies for congenital hydrocephalus. Bone marrow-derived mesenchymal stem cells (BM-MSC) are considered as a potential therapeutic tool in neurodegenerative diseases, due to their ability to migrate to degenerated tissues and the production of growth factors. In the present study, using an animal model of congenital hydrocephalus, the hyh mouse, it has been studied the capacity of the BM-MSC to reach the degenerated regions exhibiting glial reactions and their probable neuroprotector effects. The BM-MSC were isolated from two different sources: a) transgenic mice expressing the monomeric red fluorescent protein (mRFP1); b) wild type mice. In the second case, the BM-MSC were labelled in vitro using bromodeoxyuridine, a fluorescent cell tracker and the lipophilic DiR. Before application, the cells were analysed using flow cytometry and immunofluorescence. The BM-MSC were injected into the retro-orbital sinus or into the lateral ventricle of hyh mice. After 24/96 hours of administration, the BM-MSC were detected under light, confocal and electron microscopes. The injected BM-MSC reached the degenerated periventricular regions and the disrupted neurogenic niches. They were detected in the periventricular parenchyma, around periventricular blood vessels and in the ventral meninges. Most of the applied BM-MSC expressed the glial cell-derived neurotrophic factor (GDNF), in the same way as the periventricular reactive astrocytes, suggesting a possible neuroprotector effect.FIS (Instituto de Salud Carlos III)-FEDER a AJJ. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Characterization and administration of bone marrow-derived mesenchymal stem cells in an animal model of congenital hydrocephalus

Bone marrow-derived mesenchymal stem cells (BM-MSC) are considered as a potential therapeutic tool in neurodegenerative diseases, due to their ability to migrate to degenerated tissues and the production of growth factors. Congenital hydrocephalus is a disorder characterized by a degeneration of the periventricular cerebral parenchyma and the white matter. In the present study, using an animal model of congenital hydrocephalus, the hyh mouse, it has been studied the capacity of the BM-MSC to reach the degenerated regions exhibiting glial reactions and their probable neuroprotector effects. The BM-MSC were isolated from two sources: a) transgenic mice expressing the monomeric red fluorescent protein (mRFP1); b) wild type mice. In the second case, the BM-MSC were labelled in vitro using bromodeoxyuridine, a fluorescent cell tracker and the lipophilic DiR. Before application, the cells were analysed using flow cytometry and immunofluorescence. The BM-MSC were injected into the retro-orbital sinus or into the lateral ventricle of hyh mice. After 24/96 hours of administration, they were detected under light, confocal and electron microscopes. The injected BM-MSC reached the degenerated periventricular regions and the disrupted neurogenic niches. They were detected in the periventricular parenchyma, around periventricular blood vessels and in the ventral meninges. Most of the applied BM-MSC expressed the glial cell-derived neurotrophic factor (GDNF), in the same way as the periventricular reactive astrocytes, suggesting a possible neuroprotector effect.Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tech. Instituto de Salud Carlos III, PI12/0631 con cofinanciación FEDER

A synthetic collagen-binding arg-gly-asp (rgd) biomimetic peptide enhances bone cell differentiation

RGD (arginine-glycine-aspartic acid) peptides have shown some promising abilities to promote the attachment of cells to biomaterials and to direct their differentiation. However, anchoring these peptides to the biomaterial’s surface is mandatory and usually implies several chemical linking steps. The aim of this work was to design and characterize a synthetic RGD biomimetic peptide that includes a collagen-binding domain for easy one-step functionalization of absorbable collagen sponges (ACSs), which are of frequent use in orthopaedic surgery. The stable binding of biotinylated CBD-RGD peptide loaded onto ACSs was confirmed using chemiluminisence detection after washing of the sponges. Furthermore, the effect of the peptide on MC3T3-E1 mouse preosteoblasts and rat bone marrow-derived mesenchymal stem cells (MSCs) in vitro was characterized in terms of caspase activity, proliferation, alkaline phosphatase (ALP) activity, matrix mineralization and formation of focal adhesions. Finally, a rat ectopic osteogenesis model was used to determine if the co-administration of CBD-RGD could lower the dose of BMP-2 necessary to induce bone formation. The CBD-RGD peptide was demonstrated to bind stable to ACSs, even after extensive washing. In vitro, the peptide did not induce apoptosis of the cells, but positively affected both cell growth and differentiation. It also seemed to affect the cytoskeleton arrangement of MC3T3-E1 cells, favoring the establishment of focal adhesions. At last, the in vivo experiments showed that ACSs functionalized with this peptide and loaded with a subfunctional dose of BMP-2 gave rise to ectopic bone. In conclusion. the combination of CBD-RGD with the currently used collagen/BMP system might be a promising approach to improve osteogenesis and to reduce the doses of BMPs needed in clinical orthopaedics.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Squamous cell carcinoma related with dental implants. A clinical cases report.

One third of all cases of head and neck carcinoma (CA) concern the oral mucosa. The use of dental implants (DI) for dental rehabilitation is widely extended. However, a few studies have reported some cases with neoplasic alterations, among the tissue surrounding implants. Our aim was to analyze possible alterations at the bone-implant interface in patients with oral squamous cell carcinoma (SCC), providing new evidence that could relate or discard a possible link between these factors. We used, for the first time, different techniques, including electron microscopy and histology, to analyze the implants surface and the surrounding tissue from four clinical cases with neoplasic alterations surrounding DI. Histologically, ample inflammatory tissue was found in direct contact with the implant surface. Surface analysis of this tissue, revealed titanium percentages. According to our study, no oncological relation with deterioration of the implant surface was found, although DI were constantly related with peri-implantitis, a chronic trauma of the oral mucosa that could involve a neoplastic factor

RGD-dendritic structures on titanium alloy. Influence in the relationship between bone cells and the metal surface

Prosthetic implants are used in surgical procedures to replace a joint (hip or knee) allowing the functional recovery of the patient. Prostheses are usually made of titanium alloys. However, the lack of chemical and structural bond between the metal and the surrounding bone tissue causes a fail in the long term due to poor osseointegration. Titanium surface with RGD domains would positively influence the relationship between bone cells and the metal surface of the prostheses, thus promoting a better osseointegration [1]. Arginine-glycine-aspartic acid tripeptides (RGD) were conjugated to dendritic structures and used to pre-treat titanium disk. We demonstrate that dendrimer-presented tripeptides efficiently improves cell-material interaction.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

A collagen-targeted biomimetic RGD peptide to promote osteogenesis

Osteogenesis is a complex, multifactorial process in which many different signals interact. The bone morphogenetic proteins (BMPs) are the most potent inducers of osteoblastic differentiation, although very high doses of BMPs in combination with collagen type I formulations have to be used for clinical applications. Although integrin-binding arginine-glycine-aspartic acid (RGD) biomimetic peptides have shown some promising abilities to promote the attachment of cells to biomaterials and to direct their differentiation, the linking of these peptides to collagen sponges usually implies chemical manipulation steps. In this study, we describe the design and characterization of a synthetic collagen-targeted RGD biomimetic (CBD-RGD) peptide formed from a collagen-binding domain derived from the von Willebrand factor and the integrin-binding RGD sequence. This peptide was demonstrated to bind to absorbable collagen type I sponges (ACSs) without performing any chemical linking, and to induce the differentiation of MC3T3-E1 mouse preosteoblasts and rat bone marrow-derived mesenchymal stem cells. Furthermore, in vivo experiments showed that ACSs functionalized with CBD-RGD and loaded with a subfunctional dose of BMP-2-formed ectopic bone in rats, while nonfunctionalized sponges loaded with the same amount of BMP-2 did not. These results indicate that the combination of this biomimetic peptide with the currently used collagen+BMP system might be a promising approach to improve osteogenesis and to reduce the doses of BMPs needed in clinical orthopedics.MICINN (BIO2009-13903-C01-01) MINECO (BIO2012-34960) Junta de Andalucía (P07-CVI-2781) ISCiii, RETICS, Red Española de Terapia Celular (TerCel) (RD12/0019/0032) ISCiii, CIBER-BBN (CB06/01/1015

Squamous cell carcinoma related with dental implants. A clinical cases report

One third of all cases of head and neck carcinoma (CA) concern the oral mucosa. The use of dental implants (DI) for dental rehabilitation is widely extended. However, a few studies have reported some cases with neoplasic alterations, among the tissue surrounding implants. Our aim was to analyze possible alterations at the bone-implant interface in patients with oral squamous cell carcinoma (SCC), providing new evidence that could relate or discard a possible link between these factors. We used, for the first time, different techniques, including electron microscopy and histology, to analyze the implant ´s surface and the surrounding tissue from four clinical cases with neoplasic alterations surrounding DI. Histologically, ample inflammatory tissue was found in direct contact with the implant surface. Surface analysis of this tissue, revealed titanium percentages. According to our study, no oncological relation with deterioration of the implant surface was found, although DI were constantly related with peri-implantitis, a chronic trauma of the oral mucosa that could involve a neoplastic factor

Desarrollo de implantes protesicos personalizados mediante impresión 3D de metales para el tratamiento quirúrgico de defectos maxilares

La osteonecrosis mandibular es una patología que suele presentarse como efecto secundario de la radioterapia con que se tratan los procesos oncológicos de cabeza y cuello, o después de tratamientos prolongados con bifosfonatos. Su única solución posible consiste en la resección quirúrgica del hueso dañado seguida de una reconstrucción anatómico-funcional con placas metálicas e implantes de diversos materiales. Debido a la dificultad técnica de la cirugía y la mala calidad que suele presentar el hueso del paciente, dicha reconstrucción rara vez es satisfactoria, ni desde el punto de vista funcional, ni desde el estético. El desarrollo de tecnologías de impresión 3D de metales ha abierto la posibilidad de fabricar prótesis personalizadas, hechas a partir de datos de TAC del paciente, para darles la forma exacta del segmento a sustituir. El proyecto que presentamos partió de dos premisas: i) las prótesis personalizadas, fabricadas por sinterizado metálico suponen una alternativa viable, y que mejora la situación actual; y ii) la adición de elementos de ingeniería tisular podría implementar estas prótesis personalizadas, promoviendo su osteointegración. Las dos hipótesis se pusieron a prueba mediante la creación de un modelo de resección maxilar en un animal de tamaño medio (conejo), y el diseño de prótesis personalizadas a dicho defecto, que se fabricaron en aleación Ti6Al4V mediante fabricación aditiva. En un desarrollo posterior, estas prótesis se combinaron con biomateriales, biomoléculas y células mesenquimales. Los resultados obtenidos prueban la utilidad de la impresión 3D de prótesis maxilares personalizadas, y la mejora de su osteointegración mediante adición de elementos de ingeniería tisular.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech