Avaliações macroscópica e histológica do reparo da cartilagem articular equina tratada com microperfurações do osso subcondral associadas ou não à injeção intra-articular de cartogenina / Macroscopic and histological evaluations of equine joint cartilage repair treated with microperforation of the subchondral bone associated or not with intra-articular kartogenin

O objetivo deste estudo foi avaliar o reparo da cartilagem hialina equina, por meio de análises macroscópica (através de videoartroscopia) e histológica (através de fragmentos de biopsia), em defeitos condrais induzidos na tróclea lateral do fêmur tratados pela técnica de microperfurações subcondral associada ou não com administração intra-articular de cartogenina. Foram utilizados seis equinos pesando em média (±DP) 342±1,58 kg, com a idade aproximada de 7,2±1,30 anos e escore corporal de 7,1±0,75, que foram submetidos a videoartroscopia para indução da lesão condral de 1 cm2 na tróclea lateral do fêmur e realização da técnica de microperfuração do osso subcondral de ambos os joelhos. Foram realizadas quatro aplicações semanais com 20 μM de cartogenina intra-articulares em um dos joelhos (grupo tratado) e solução de ringer com lactato na articulação contralateral (grupo controle). Após o período de 60 dias, foram feitas as avaliações macroscópicas, através de videoartroscopias, e histológicas, através de biopsia. Não foram observadas diferenças significativas nos escores macroscópicos e histológicos para reparação condral entre animais dos grupos tratados e não tratados (P>0,05). De modo geral, a porcentagem média de cartilagem hialina no tecido de reparo (17,5%) foi condizente com a literatura internacional usando outros tipos de perfuração condral. Entretanto, não se observaram diferenças estatísticas entre grupos (P>0,05). A terapia com cartogenina, segundo protocolo utilizado, não produziu melhora do processo cicatricial em lesões condrais induzidas e tratadas com microperfurações na tróclea lateral do fêmur em equinos.

The aim of this study was to evaluate the joint cartilage repair by macroscopic (via arthroscopy) and histological (biopsy fragments) analyses in chondral defects induced into equine femoral trochlea treated by microperforation associated with or without intra-articular administration of kartogenin. Six horses weighing 342±1.58 kg (mean ± SD), aged approximately 7.2±1.30 years and with a body condition score of 7.1±0.75, were used. The horses underwent arthroscopy for induction of 1-cm2 chondral lesions in lateral femoral trochlea immediately treated by microperforation of the subchondral bone of both knees. Four weekly intra-articular injections of kartogenin (20μM) in one knee (treated group) and Ringer lactate solution in the contralateral joint (control group) were performed during the postoperative period. After 60 days, macroscopic evaluations were performed by video-arthroscopy, and biopsy samples of the repair tissue were taken for histopathological healing evaluation. No significant change was observed in macroscopic and histological scores for chondral healing between treated and untreated groups (P>0.05). The overall mean percentage of hyaline cartilage in both groups (17.5%) was consistent with other international studies using other types of chondral microperforation; however, no statistical differences were observed between groups (P>0.05). In conclusion, the therapy with kartogenin, according to the used protocol, did not produce any macroscopic and histological healing improvement in induced chondral lesions treated with microperforations in equine femoral trochlea.

Functional disruption of human leukocyte antigen II in human embryonic stem cell

BACKGROUND: Theoretically human embryonic stem cells (hESCs) have the capacity to self-renew and differentiate into all human cell types. Therefore, the greatest promise of hESCs-based therapy is to replace the damaged tissues of patients suffering from traumatic or degenerative diseases by the exact same type of cells derived from hESCs. Allo-graft immune rejection is one of the obstacles for hESCs-based clinical applications. Human leukocyte antigen (HLA) II leads to CD4+ T cells-mediated allograft rejection. Hence, we focus on optimizing hESCs for clinic application through gene modification. RESULTS: Transcription activator-like effector nucleases (TALENs) were used to target MHC class II transactivator (CIITA) in hESCs efficiently. CIITA(-/-)hESCs did not show any difference in the differentiation potential and self-renewal capacity. Dendritic cells (DCs) derived from CIITA(-/-)hESCs expressed CD83 and CD86 but without the constitutive HLA II. Fibroblasts derived from CIITA(-/-)hESCs were powerless in IFN-γ inducible expression of HLA II. CONCLUSION: We generated HLA II defected hESCs via deleting CIITA, a master regulator of constitutive and IFN-γ inducible expression of HLA II genes. CIITA(-/-)hESCs can differentiate into tissue cells with non-HLA II expression. It's promising that CIITA(-/-)hESCs-derived cells could be used in cell therapy (e.g., T cells and DCs) and escape the attack of receptors' CD4+ T cells, which are the main effector cells of cellular immunity in allograft.

Cancer stem cells - the current status of an old concept: literature review and clinical approaches

As regards their morphology and biology, tumours consist of heterogeneous cell populations. The cancer stem cell (CSC) hypothesis assumes that a tumour is hierarchically organized and not all of the cells are equally capable of generating descendants, similarly to normal tissue. The only cells being able to self-renew and produce a heterogeneous tumour cell population are cancer stem cells. CSCs probably derive from normal stem cells, although progenitor cells may be taken into consideration as the source of cancer stem cells. CSCs reside in the niche defined as the microenvironment formed by stromal cells, vasculature and extracellular matrix. The CSC assays include FACS sorting, xenotransplantation to immunodeficient mice (SCID), incubation with Hoechst 33342 dye, cell culture in non-adherent conditions, cell culture with bromodeoxyuridine. CSCs have certain properties that make them resistant to anticancer therapy, which suggests they may be the target for potential therapeutic strategies.