Cell Therapy and Tissue Engineering Approaches for Cartilage Repair and/or Regeneration

Articular cartilage injuries caused by traumatic, mechanical and/or by progressive degeneration result in pain, swelling, subsequent loss of joint function and finally osteoarthritis. Due to the peculiar structure of the tissue (no blood supply), chondrocytes, the unique cellular phenotype in cartilage, receive their nutrition through diffusion from the synovial fluid and this limits their intrinsic capacity for healing. The first cellular avenue explored for cartilage repair involved the in situ transplantation of isolated chondrocytes. Latterly, an improved alternative for the above reparative strategy involved the infusion of mesenchymal stem cells (MSC), which in addition to a self-renewal capacity exhibit a differentiation potential to chondrocytes, as well as a capability to produce a vast array of growth factors, cytokines and extracellular matrix compounds involved in cartilage development. In addition to the above and foremost reparative options up till now in use, other therapeutic options have been developed, comprising the design of biomaterial substrates (scaffolds) capable of sustaining MSC attachment, proliferation and differentiation. The implantation of these engineered platforms, closely to the site of cartilage damage, may well facilitate the initiation of an \'in situ' cartilage reparation process. In this mini-review, we examined the timely and conceptual development of several cell-based methods, designed to repair/regenerate a damaged cartilage. In addition to the above described cartilage reparative options, other therapeutic alternatives still in progress are portrayed.

Implante de células progenitores en cardiología: su eficacia es aún incierta / Stem cell implantation in cardiology: its efficacy remains uncertain

Para superar la capacidad endógena limitada de regeneración de miocardiocitos post infarto del miocardio, se formuló la hipótesis de que al repoblar la zona infartada con células progenitoras autólogas se podría restablecer la función cardíaca, iniciándose una intensa investigación preclínica y luego clínica. La mejoría inicial, pequeña, en la función cardíaca no se correlaciona con la diferenciación de células progenitores a miocitos. Se han propuesto efectos auto y paracrinos como alternativas para explicar efectos beneficiosos del implante de células progenitoras. Se han usado diferentes protocolos y técnicas para investigar mecanismos de acción y eficacia de los implantes mencionados pero sus resultados no son claros. Se requiere de estudios más extensos y específicos para resolver la pregunta planteada al inicio de este editorial.

In order to overcome the limited regenerative capacity of cardiac myocytes following a myocardial infarction, the implant of stem cells was proposed as a means of restablishing cardiac function. Thus, an extensive line of preclinical and clinical investigation was developed. Initial improvements, admittedly small, in cardiac function do not correlate with differentiation of stem cells to myocytes. Autocrine and paracrine effects have been proposed as an alternative way to explain beneficial effects of BMC implantation. There have been many approaches, protocols and techniques used to investigate the mechanisms of action and efficacy of BMC implant but their result continue to be controversial. Therefore, larger and more specific studies are needed to solve the question posed at the beginning of this editorial.

Masa cardíaca derecha: a propósito de un caso / Clinical case: right ventricular intracardiac mass

El presente caso clínico trata de una paciente mujer de 42 años, en quien se encuentra una masa intracardíaca del corazón derecho, que estudiada con imágenes derivadas de ecocardiografía de superficie y transesofágica lleva a la sospecha de trombo, que es confirmado tras excéresis quirúrgica. Se analizan las etiopatogenias posibles y diagnóstico diferencial de masas intracardíacas.

A 42 year old woman is found to have right ventricular of intracardiac mass through surface and transesophageal echocardiography. Characteristics of the mass suggest a thrombus which is confirmed at the time of surgical removal. Different etiologies and differential diagnosis of intracardiac masses is discussed.

Stem cell implantation for osteonecrosis of the femoral head

What is the most effective treatment for the early stages of osteonecrosis of the femoral head? We assessed multiple drilling and stem cell implantation to treat the early stages of osteonecrosis of the femoral head. We report the clinical and radiological results of stem cell implantation and core decompression. In total, 128 patients (190 hips) who had undergone surgery were divided into two groups based on which treatment they had received: (1) multiple drilling and stem cell implantation or (2) core decompression, curettage and a bone graft. The clinical and radiographic results of the two groups were compared. At 5-year follow-up, in the stem cell implantation group, 64.3% (27/42) of the patients with Stage IIa disease, 56.7% (21/37) of the patients with Stage IIb disease and 42.9% (21/49) of the patients with Stage III disease had undergone no additional surgery. In the conventional core decompression group, 64.3% (9/14) of the patients with Stage IIa disease, 55.6% (5/9) of the patients with Stage IIb disease and 37.5% (3/8) of the patients with Stage III disease had undergone no additional surgery. Success rates were higher in patients with Ficat Stage I or II lesions than in those with Stage III lesions. There were no statistically significant differences between the groups in terms of success rate or in the clinical and radiographic results of the two methods. Essentially the same results were found with stem cell implantation as with the conventional method of core decompression.

Comparison of kidney tubular epithelial cells and endothelial cells grown on titania nanotubes / 中华肾脏病杂志

Objective To observe the adhesion and growth of LLC-PK1 cells and ECV304 cells on titania nanotube arrays, and provide evidence for construction of miniaturation bioartificial kidney. Methods Four different diameters nanotube materials were prepared by anodic oxidation, each material was processed by unannealed and with UV irradiation, annealed and without UV irradiation, annealed and with UV irradiation, respectively, which had 12 groups totally,then two kinds of cells were separately grown on the 12 materials. The adhesion and growth of the two kinds of cells were studied under a fluorescence microscope. MTT assay was used to test the activity of two kinds of cells on different diameters and the proliferation of two kinds of cells on 70 nm diameters. Results The adhesion and proliferation of two kinds of cells on TiO2 nanotube arrays were basically consistent, both on anatase TiO2 nanotubes with 70 nm diameter but without UV irradiation showed the optimal adhesion and activity. The activities of LLC-PK1 cells and ECV304 cells were both increased with time extended, while the absorbance of ECV304 cells was higher on pure Ti film than on titania nanotube. Conclusion TiO2 nanotube is beneficial to LLC-PK1 cells, but is unfavorable for ECV304 cells when they grow alone.

Current situation on tissue engineering heart valve research and its future / 第二军医大学学报

Valvular disease is a commonly seen heart disorder,valve replacement is an effective approach to treat valve disorders.Both the mechanic valves and bioprosthesis used now have their own defects,making it important for the cardio surgery field to develop some kind of ideal valves.With the development of tissue engineering techniques,the tissue engineering valves are thought to have great potential and bright clinical future,and now it has become a hot point in cardiac surgery.This article is to evaluate the frame materials,resource of tissue cells and implantation, in vitro pre adaptation testing and in vivo animal experiment results,and the existing problems are pointed out in the present study.