Autologous Mesenchymal Stromal Cells Immobilized in Plasma-Based Hydrogel for the Repair of Articular Cartilage Defects in a Large Animal Model

The treatment of cartilage defects in trauma injuries and degenerative diseases represents a challenge for orthopedists. Advanced mesenchymal stromal cell (MSC)-based therapies are currently of interest for the repair of damaged cartilage. However, an approved system for MSC delivery and maintenance in the defect is still missing. This study aimed to evaluate the effect of autologous porcine bone marrow MSCs anchored in a commercially available polyglycolic acid-hyaluronan scaffold (Chondrotissue®) using autologous blood plasma-based hydrogel in the repair of osteochondral defects in a large animal model. The osteochondral defects were induced in twenty-four minipigs with terminated skeletal growth. Eight animals were left untreated, eight were treated with Chondrotissue® and eight received Chondrotissue® loaded with MSCs. The animals were terminated 90 days after surgery. Macroscopically, the untreated defects were filled with newly formed tissue to a greater extent than in the other groups. The histological evaluations showed that the defects treated with Chondrotissue® and Chondrotissue® loaded with pBMSCs contained a higher amount of hyaline cartilage and a lower amount of connective tissue, while untreated defects contained a higher amount of connective tissue and a lower amount of hyaline cartilage. In addition, undifferentiated connective tissue was observed at the edges of defects receiving Chondrotissue® loaded with MSCs, which may indicate the extracellular matrix production by transplanted MSCs. The immunological analysis of the blood samples revealed no immune response activation by MSCs application. This study demonstrated the successful and safe immobilization of MSCs in commercially available scaffolds and defect sites for cartilage defect repair.

Cryopreservation of organoids

Organoids represent indispensable opportunities for biomedicine, including drug discovery, cancer biology, regenerative and personalised medicine or tissue and organ transplantation. However, the lack of optimized preservation strategies limits the wide use of organoids in research or clinical fields. In this review, we present a short outline of the recent developments in organoid research and current cryopreservation strategies for organoid systems. While both vitrification and slow controlled freezing have been utilized for the cryopreservation of organoid structures or their precursor components, the controlled-rate slow freezing under protection of Me2SO remains the most common approach. The application of appropriate pre- or post-treatment strategies, like the addition of Rho-kinase or myosin inhibitors into cell culture or cryopreservation medium, can increase the recovery of complex organoid constructs post-thaw. However, the high complexity of the organoid structure and heterogeneity of cellular composition bring challenges associated with cryoprotectant distribution, distinct response of cells to the solution and freezing-induced injuries. The deficit of adequate quality control methods, which may ensure the assessment of organoid recovery in due term without prolonged re-cultivation process, represents another challenge limiting the reproducibility of current cryobanking technology. In this review, we attempt to assess the current demands and achievements in organoid cryopreservation and highlight the key questions to focus on during the development of organoid preservation technologies. Doi: 10.54680/fr23210110112.

Alginate Encapsulation to Enhance Biopreservation Scope and Success: A Multidisciplinary Review of Current Ideas and Applications in Cryopreservation and Non-Freezing Storage

BACKGROUND

The development of encapsulation technologies has played an important role in improving cryopreservation outcomes for many cell and tissue types over the past 20 years. Alginate encapsulation cryopreservation (AECryo) has been incorporated into a range of applications in biotechnology, species conservation and clinical therapies, using cells from many different phyla, including higher plants, animal and human cells. This review describes the background to the origins of AECryo, the development of AECryo in higher plant tissues, broadening to current applications in algal conservation, the roles for AECryo in preserving phytodiversity, fungal species and in animal and human cells.

OBJECTIVE

The main aims are to provide information resources on AECryo in different areas of biology and to stimulate new ideas for wider applications and future improvement. The translation of this useful biopreservation strategy into new opportunities for cell cryopreservation and storage at non-freezing temperatures are also discussed.

Myxopapillary ependymoma: correlation of clinical and imaging features with surgical resectability in a series with long-term follow-up

STUDY DESIGN

Retrospective case series.

OBJECTIVES

The objective of this study is to identify imaging and intraoperative characteristics that may predict surgical resection for myxopapillary ependymoma (MPE). The diffuse involvement in the conus-filum region makes complete resection challenging. The preoperative characteristics that may estimate the extent of resection has not been reported.

SETTING

Toronto, Canada.

METHODS

All MPE cases between 1972 and 2005 at a single institution were identified and reexamined by a neuropathologist. Neurological outcomes (Frankel scale), clinical features, operative findings, pre and postoperative imaging results were reviewed.

RESULTS

A total of 18 operations were performed on 15 MPE patients (8 females/7 males; age range: 18-71 years). Median postoperative follow-up was 56 months. Three patients (17%) developed tumor regrowth requiring reoperations. Preoperative magnetic resonance imaging (MRI; in 14/18 procedures) determined that tumors involved the conus in 70% of cases, which was significantly associated with intraoperative findings (P=0.02). Complete microsurgical resection was accomplished in 4 out of 7 cases where conus was not involved, but in only 1 out of 10 cases with conus involvement (P=0.056). The degree of conus involvement in one case was unclear. None of patients with total surgical resection developed recurrence. All patients survived at long-term follow-up.

CONCLUSION

Our series is the first to correlate MPE involvement to conus medullaris on preoperative MRI with intraoperative findings, and examine its significance on surgical resectability. This information could guide clinicians in preoperative planning and advising patients on treatment options and potential risks/benefits. MRI is very sensitive (100%) and moderately specific (67%) in detecting direct anatomical contact between conus and MPE tumors.

An assessment of P-glycoprotein expression and activity in peripheral blood lymphocytes of transplant candidates

BACKGROUND

P-glycoprotein (P-gp) is involved in the transport of the xenobiotic immunosuppressive agents and many cytokines, such as IL-2 and IFN-gamma. Hence, P-gp activity on peripheral blood lymphocytes (PBLs) could affect the pharmacologic response to xenobiotic immunosuppressants and immune responsiveness. The objectives of this study were to (1) determine the level of P-gp expression and activity on PBLs of kidney transplant candidates; and (2) determine whether P-gp expression correlates with P-gp activity.

METHODS

We measured P-gp expression and activity on CD3(+)/CD8(+), CD3(+)/CD4(+), B lymphocytes, and NK cells of 36 kidney transplant candidates using a flow cytometric assay. P-gp activity was determined for each subpopulation of cells by the ratio of the mean Rhodamine 123 fluorescence (MFI Rh123) in the presence of verapamil divided by the MFI Rh123 in the absence of verapamil. P-gp expression was noted as the percentage of P-gp(+) cells.

RESULTS

NK cells exhibited the greatest amount of P-gp activity (MFI Rh123 = 20.2 +/- 16.4) compared with other cell populations (P < .05). P-gp efflux activity was also significantly elevated in CD3(+)/CD8(+) cells (13.9 +/- 10.5) compared with B lymphocytes (4.9 +/- 2.7; P < .05) and CD4/CD3(+) cells (2.4 +/- 1.0; P < .05). P-gp expression was significantly higher in B lymphocytes (11.7 +/- 9.5) and NK cells (10.2 +/- 7.3) when compared with CD3(+)/CD8(+) cells (7.3 +/- 6.9) and CD3(+)/CD4(+) cells (6.4 +/- 3.8). P-gp expression was highly variable and did not correlate with P-gp activity (P > .05).

CONCLUSIONS

CD3(+)/CD8(+) cells and NK cells, exhibited significantly increased P-gp activity compared with the other cell populations. P-gp expression is not a good correlate of P-gp activity. These findings may have important implications for the use of immunosuppressive drugs posttransplant and immune responsiveness after transplantation.