Topical Review: MACI as an Emerging Technology for the Treatment of Talar Osteochondral Lesions

Cartilage Injuries: Basic Science Update

The last several decades have brought about substantial development in our understanding of the biomolecular pathways associated with chondral disease and progression to arthritis. Within domains relevant to foot and ankle, genetic modification of stem cells, augmentation of bone marrow stimulation techniques, and improvement on existing scaffolds for delivery of orthobiologic agents hold promise in improving treatment of chondral injuries. This review summarizes novel developments in the understanding of the molecular pathways underlying chondral damage and some of the recent advancements within related therapeutics.

Effect study of exosomes derived from platelet-rich plasma in the treatment of knee cartilage defects in rats

BACKGROUND

The repair of articular cartilage defects has always been a difficult problem. We aimed to investigate the therapeutic effect of intra-articular injection of platelet-rich plasma (RPR) and PRP-derived exosomes (PRP-Exos) on cartilage defects in rat knee joints and then provide experience for the use of PRP-exos in cartilage defect repair.

METHODS

Rat abdominal aortic blood was collected, and PRP was extracted by two-step centrifugation. PRP-exos were obtained by kit extraction, and PRP-exos were identified by various methods. After the rats were anesthetized, a cartilage defect subchondral bone was created at the proximal end of the origin of the femoral cruciate ligament with a drill. SD rats were divided into 4 groups, including PRP group, 50 μg/ml PRP-exos group, 5 μg/ml PRP-exos group, and control group. One week after the operation, 50 μg/ml PRP, 50 μg/ml PRP-exos, 5 μg/ml PRP-exos and normal saline were injected into the knee joint cavity of rats in each group, once a week. A total of two injections were given. On the 5th and 10th week after drug injection, the serum levels of matrix metalloproteinase 3 (MMP-3) and tissue inhibitor of matrix metalloproteinase 1 (TIMP-1) were detected by each treatment method, respectively. The rats were killed at the 5th and 10th weeks, respectively, and the cartilage defect repair was observed and scored. The defect repair tissue sections were used for HE staining and type II collagen immunohistochemical staining.

RESULTS

The histological results showed that both PRP-exos and PRP could promote cartilage defect repair and type II collagen formation, and the promoting effect of PRP-exos was significantly better than that of PRP. In addition, enzyme-linked immunosorbent assay (ELISA) results showed that compared with PRP, PRP-exos could significantly increase serum TIMP-1 and decrease serum MMP-3 in rats. And the promoting effect of PRP-exos was concentration dependent.

CONCLUSION

Intra-articular injection of PRP-exos and PRP can promote the repair of articular cartilage defects, and the therapeutic effect of PRP-exos is better than the same concentration of PRP. PRP-exos are expected to be an effective treatment for cartilage repair and regeneration.

High-Density Autologous Chondrocyte Implantation as Treatment for Ankle Osteochondral Defects

PURPOSE

Two-year follow-up to assess efficacy and safety of high-density autologous chondrocyte implantation (HD-ACI) in patients with cartilage lesions in the ankle.

DESIGN

Twenty-four consecutive patients with International Cartilage repair Society (ICRS) grade 3-4 cartilage lesions of the ankle were included. Five million chondrocytes per cm² of lesion were implanted using a type I/III collagen membrane as a carrier and treatment effectiveness was assessed by evaluating pain with the visual analogue scale (VAS) and American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score at baseline, 12-month, and 24-month follow-up, together with dorsal and plantar flexion. Magnetic resonance observation for cartilage repair tissue (MOCART) score was used to evaluate cartilage healing. Histological study was possible in 5 cases.

RESULTS

Patients' median age was 31 years (range 18-55 years). Median VAS score was 8 (range 5-10) at baseline, 1.5 (range 0-8) at 12-month follow-up, and 2 (rang e0-5) at 24-month follow-up (P < 0.001). Median AOFAS score was 39.5 (range 29-48) at baseline, 90 (range 38-100) at 12-month follow-up, and 90 (range 40-100) at 24-month follow-up (P < 0.001). Complete dorsal flexion significantly increased at 12 months (16/24, 66.7%) and 24 months (17/24, 70.8%) with regard to baseline (13/24, 54.2%) (P = 0.002). MOCART at 12- and 24-month follow-ups were 73.71 ± 15.99 and 72.33 ± 16.21. Histological study confirmed that neosynthetized tissue was cartilage with hyaline extracellular matrix and numerous viable chondrocytes.

CONCLUSION

HD-ACI is a safe and effective technique to treat osteochondral lesions in the talus, providing good clinical and histological results at short- and mid-term follow-ups.

Operative treatments for osteochondral lesions of the talus in adults: A systematic review and meta-analysis

PURPOSE

This systematic review aimed to identify the available evidence regarding the comparative effectiveness and safety of various operative treatments in adult patients with osteochondral lesions of the talus (OLT).

MATERIALS AND METHODS

The PubMed, Embase, ISI Web of Knowledge, and the Cochrane Controlled Trial Register of Controlled Trials were searched from their inception date to September 2019. Two reviewers selected the randomized controlled trials (RCTs) and non-RCTs assessing the comparative effectiveness and safety of various operative treatments for OLT. The meta-analysis was performed using Revman 5.3.

RESULTS

Eight studies (1 RCT and 7 non-RCTs) with 375 patients were included in this review. The difference in the American Orthopaedic Foot and Ankle Society (AOFAS) score between the cartilage repair and replacement was not significant. The cartilage regeneration with or without cartilage repair had significant superiority in improving the AOFAS score compared with the cartilage repair. The difference in the magnetic resonance observation of cartilage repair tissue score between the cartilage repair and replacement and between cartilage repair and cartilage repair plus regeneration was significant.

CONCLUSIONS

Cartilage regeneration and cartilage repair plus regeneration had significant superiority in improving the ankle function and radiological evaluation of OLT, although the trials included did not have high-level evidence. Moreover, which treatment between the 2 was safer could not be addressed in this review as most of the trials did not report the safety outcome. Further studies are needed to define the best surgical option for treating OLT.

Biological Products: Cellular Therapy and FDA Approved Products

The pace of advances in the world of science have created new opportunities and insights that give us new and more understanding of our nature and environment. Among the different fields of science, new medical sciences have drawn a great deal of attention among medical science researchers and the society. The hope for finding treatments for incurable diseases and further improvement of man's health is growing thanks to new medical technologies. Among the novel medical fields that have been extensively covered by medical and academic societies are cell therapy and gene therapy that are categorized under regenerative medicine. The present paper is an attempt to introduce the prospect of a curative cell-based therapy and new cellular and gene therapy drugs that have been recently approved by FDA (food and drug administration). Cellular and gene therapy are two very close fields of regenerative medicine and sciences which their targets and applications can be discussed together. What adds to the importance of this new field of science is the possibility to translate the hope for treatment of incurable diseases into actual treatments. What follows delves deeper into this new field of science and the drugs.

[Research progress in surgical procedures for osteochondral lesions of talus]

Objective

To summarize the research progress of surgical procedures in osteochondral lesions of the talus (OLT).

Methods

By consulting the related literature of OLT in recent years, the advantages and disadvantages of various surgical treatment schemes were analyzed and summarized.

Results

There are many surgical treatments for OLT, including bone marrow stimulation, osteochondral transplantation, autologous chondrocyte transplantation, and biologically assisted therapy. Various schemes have different indications and limitations. With the continuous development of various technologies, the effectiveness of OLT treatment will gradually improve.

Conclusion

There are still many difficulties and controversies in the treatment of OLT, and there is no unified treatment plan. It is suggested that individualized operation plan should be formulated according to the specific conditions of patients.