OBJECTIVE
Autologous chondrocyte implantation (ACI) has been successfully used for the treatment of osteochondral lesions of the talus. One of the main problems of this surgical strategy is related to the harvesting of the cartilage slice from a healthy knee. The aim of this study was to examine the capacity of chondrocytes harvested from a detached osteochondral fragment to proliferate and to serve as a source of viable cells for ACI in the repair of ankle cartilage defects.


METHODS
Detached osteochondral fragments harvested from the ankle joint of 20 patients with osteochondral lesions of the talus served as the source of human articular cartilage specimens. All of the osteochondral lesions were chronic and of traumatic origin. In all cases, the fragments were utilized to evaluate the viability and proliferation of the cells, the histological appearance of the cartilage tissue and the expression of specific cartilage markers by real-time polymerase chain reaction (PCR). In the 16 patients scheduled for ACI, the expanded chondrocytes were used for chondrocyte implantation. In the other 4 patients, with lesion size <1.5cm(2), microfractures were created during the initial arthroscopic step. As a control group, 7 patients with comparable osteochondral lesions underwent the same surgery, but received chondrocytes harvested from the ipsilateral knee.


RESULTS
According to the American Orthopaedic Foot and Ankle Scoring (AOFAS) system, patients in the experimental group had a preoperative score of 54.2+/-16 points and a postoperative one of 89+/-9.6 points after a minimum follow-up time of 12 months (P<0.0005). The control group of patients had a preoperative score of 54.6+/-11.7 points and a postoperative one of 90.2+/-9.7 points at a minimum follow-up time of 12 months (P<0.0005). The clinical results of the two groups did not differ significantly from each other. Chondrocytes isolated from the detached fragments were highly viable, phenotypically stable, proliferated in culture and redifferentiated when grown within the three-dimensional scaffold used for ACI. The morphological and molecular characteristics of the cartilage samples obtained from the detached osteochondral fragments were similar to those of healthy hyaline articular cartilage.


CONCLUSIONS
The good results achieved with this strategy indicate that cells derived from the lesioned area may be useful in the treatment of osteochondral defects of the talus.

The detached osteochondral fragment as a source of cells for autologous chondrocyte implantation (ACI).

Autologous chondrocyte implantation (ACI) is a therapy for articular cartilage and osteochondral lesions that relies on notch- or trochlea-derived primary chondrocytes. An alternative cell source for ACI could be osteochondritis dissecans (OCD) fragment-derived chondrocytes. Assessing the potential of these cells, we investigated their characteristics ex vivo and after monolayer expansion, as monolayer expansion is an integral step of ACI. However, as monolayer expansion can induce de-differentiation, we asked whether monolayer-induced de-differentiation can be reverted through successive alginate bead culture. Chondrocytes were isolated from the OCD fragments of 15 patient knees with ICRS grades 3–4 lesions for ex vivo analyses, primary alginate bead culture, monolayer expansion, and alginate bead culture following monolayer expansion for attempting re-differentiation. We determined yield, viability, and the mRNA expression of aggrecan and type I, II, and X collagen. OCD fragment-derived chondrocyte isolation yielded high numbers of viable cells with a low type I:II collagen expression ratio (  1. OCD fragment derived human chondrocytes may hold not yet utilized clinical potential for cartilage repair.

/pdf/human-osteochondritis-dissecans-fragment-derived-chondrocyte-50ullab1qe.pdf

Human osteochondritis dissecans fragment-derived chondrocyte characteristics ex vivo, after monolayer expansion-induced de-differentiation, and after re-differentiation in alginate bead culture

Several tissue engineering stem cell-based procedures improve hyaline cartilage repair. In this work, the chondrogenic potential of dental pulp stem cell (DPSC) organoids or microtissues was studied. After several weeks of culture in proliferation or chondrogenic differentiation media, synthesis of aggrecan and type II and I collagen was immunodetected, and SOX9, ACAN, COL2A1, and COL1A1 gene expression was analysed by real-time RT-PCR. Whereas microtissues cultured in proliferation medium showed the synthesis of aggrecan and type II and I collagen at the 6th week of culture, samples cultured in chondrogenic differentiation medium showed an earlier and important increase in the synthesis of these macromolecules after 4 weeks. Gene expression analysis showed a significant increase of COL2A1 after 3 days of culture in chondrogenic differentiation medium, while COL1A1 was highly expressed after 14 days. Cell-cell proximity promotes the chondrogenic differentiation of DPSCs and important synthesis of hyaline chondral macromolecules.

/pdf/chondrogenic-potential-of-human-dental-pulp-stem-cells-4ujwq2dq9s.pdf

Chondrogenic Potential of Human Dental Pulp Stem Cells Cultured as Microtissues.

Hyaline cartilage’s inability to self-repair can lead to osteoarthritis and joint replacement. Various treatments, including cell therapy, have been developed for cartilage damage. Autologous chondrocyte implantation (ACI) is considered the best option for focal chondral lesions. In this article, we aimed to create a narrative review that highlights the evolution and enhancement of our chondrocyte implantation technique: High-Density-ACI (HD-ACI) Membrane-assisted Autologous Chondrocyte Implantation (MACI) improved ACI using a collagen membrane as a carrier. However, low cell density in MACI resulted in softer regenerated tissue. HD-ACI was developed to improve MACI, implanting 5 million chondrocytes per cm2, providing higher cell density. In animal models, HD-ACI formed hyaline-like cartilage, while other treatments led to fibrocartilage. HD-ACI was further evaluated in patients with knee or ankle defects and expanded to treat hip lesions and bilateral defects. HD-ACI offers a potential solution for cartilage defects, improving outcomes in regenerative medicine and cell therapy. HD-ACI, with its higher cell density, shows promise for treating chondral defects and advancing cartilage repair in regenerative medicine and cell therapy.

Cartilage Defect Treatment Using High-Density Autologous Chondrocyte Implantation (HD-ACI)

The aim of the study was to investigate biofilm formation in Gram negative bacteria and to quantify biofilm production applying a new developed technique that made possible to compare results about biofilm formation within the different Gram negative bacteria species. A total of 153 Gram negative strains corresponding to 12 different bacterium species were studied applying a variation of the optic density measurement technique reported by Stepanovic et al. Data obtained with optic density analysis allow to classify microorganisms in strong biofilm developers, moderate biofilm developers, weak biofilm developers and no biofilm developers. The results were expressed in two ways, using in both cases the same statistical method: without standardization, where controls were different depending on the day optic density measurements were performed, and standardized using a correction factor, using the same control for every strain of all our bacterium species in our study, which allows result homogenization. The obtained results in our study after data analysis and standardization show that over the 153 Gram negative strains in our study, 105 of them were no biofilm developers, representing 63.75% of all the studied bacterium genera. We consider that standardization and quantification of biofilm development in Gram negative bacteria can be useful in clinical practice, because biofilm development ability can lead or focus the gold treatment of pathologies produced by these microorganisms.

[Biofilm score: is it a differential element within gram negative bacilli?].

ObjectiveTo study if a culture of chondrocytes can be obtained from pathologic hyaline cartilage (PHC) fragments.DesignTwenty-five men and 9 women with osteochondritis dissecans (OCD) in 11 cases, arthrosis in 13 patients, and trauma in the remaining 10 cases were included. The PHC fragments and a small sample of the next healthy cartilage were extracted by arthroscopy. According to the appearance, the PHC samples were divided into fixed (3 cases), flapped (6 patients), or loose bodies (25 cases), depending on the attachment degree of the cartilage to the subchondral bone. Approximately half of each pathologic sample and the whole healthy one were digested to isolate the cells trying to establish the cell culture.ResultsWe were able to establish a cell culture in 7 out of 34 (20.6%) PHC samples (positive samples), whereas in the remaining 27 (79.4%) no cell growth was observed (negative samples). Most of the negative samples were loose bodies (P = 0.005) taken from patients with OCD or arthrosis (P = 0.00...

Viability of Pathologic Cartilage Fragments as a Source for Autologous Chondrocyte Cultures

The aim of the study was to explore the structure and growth dynamics of Staphylococcus aureus resistant to methicillin (MRSA) colonies using semithin sections visualized by light microscope. One S. aureus susceptible to methicillin (MSSA) and one MRSA clinical strains were studied. Colonies in agar plates were embedded in epoxy resin after each incubation period (24 h and 48 h) at 37 degrees . Semithin sections of 0.5 µm were stained with toluidine blue and visualized by light microscope. Microscopically, no structural differences were observed between SASM and SARM colonies but differences were observed in both strains between 24 and 48 h incubation periods. Colonies showed two layers clearly differentiated at 24 h independently of the resistance to methicillin: (A) one basal layer with high density of population in contact with culture media, and (B) one superficial layer with a lower density of population. Colonies showed four layers at 48 h: (A) one basal layer with high density of population; (B) one clear layer constituted by very degraded bacterial remains in which can be observed cocci dispersed with their dyeing properties; (C) one mixed layer constituted by viable bacteria and little degraded bacterial remains (D) one superficial layer with a lower density of population than basal layer. Colonial architecture is a complex and time-dependent process.

/pdf/colonial-architecture-and-growth-dynamics-of-staphylococcus-1hyk1ryx6g.pdf

Colonial architecture and growth dynamics of Staphylococcus aureus resistant to methicillin.

A prolonged, perplexing pyrexia.

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Viability of Pathologic Cartilage Fragments as a Source for Autologous Chondrocyte Cultures

Colonial architecture and growth dynamics of Staphylococcus aureus resistant to methicillin.

A prolonged, perplexing pyrexia.