Characterisation of cells in regenerating cartilage from autotransplanted perichondrium. immunohistochemical expression of smooth-muscle actin, desmin, vimentin, and Ki-67

Proliferation ability of particulated juvenile allograft cartilage

Background

Particulated juvenile allograft cartilage (PJAC) has a good short-term clinical efficacy in repairing articular cartilage defects, but the proliferation ability of PJAC and the biological characteristics of transplanted cells after transplantation are still unclear.

Purpose

To study the cartilage proliferation ability of PJAC in repairing full-thickness cartilage defects and the reasons for proliferation to provide experimental evidence for its clinical application.

Study design

Controlled laboratory study.

Methods

Twenty Guizhou minipigs were randomly divided into the experimental group and control group. In all minipigs, an 8-mm cylindrical full-thickness cartilage defect was created in the femoral trochlea of one knee. The experimental group received PJAC transplantation from five juvenile donors of Guizhou minipigs (PJAC group; n = 10) and the control group received transplantation of autologous cartilage chips (ACC group; n = 10). Both groups were followed at 1 and 3 months after surgery, immunohistochemical evaluation of the tissue sections Ki-67 and Lin28 was conducted, the positive rate was calculated according to the staining, and the proliferation ability of PJAC was analyzed.

Results

All 20 Guizhou minipigs were followed, and there was no infection or incision healing disorder after surgery. By Ki-67 and Lin28 immunohistochemical tests, the positive rate of Ki-67 was 88.9 ± 0.2% in the PJAC group and 28.3 ± 3.6% in the ACC group at 1 month, and the difference was statistically significant (P < 0.05); the positive rate of Lin28 was 34.6 ± 3.3% in the PJAC group and 7.6 ± 1.4% in the ACC group at 1 month, and the difference was statistically significant (P < 0.05). At 3 months, the positive rates of Ki-67 in the PJAC group and ACC group were 53.6 ± 6.9% and 1.97 ± 0.3%, respectively (P < 0.05); the positive rates of Lin28 were 86.6 ± 3.3% and 1.4 ± 0.3%, respectively (P < 0.01).

Conclusion

A large animal model was established with Guizhou minipigs, and the expressions of Ki-67 protein and Lin28 protein detected by immunohistochemistry in the repaired transplanted tissue of the PJAC group were stronger than those of adult cartilage. The proliferation of PJAC within 3 months of transplantation was stronger than that of adult cartilage. The enhanced expression of Lin28 may be one of the mechanisms by which PJAC achieved stronger proliferation ability than adult cartilage. PJAC technology has shown good application prospects for repairing cartilage defects.

Autologous tragal perichondrium transplantation: a novel approach for the management of painful bullous keratopathy

PURPOSE

To introduce autologous tragal perichondrium transplantation as a novel surgical modality for the management of intractable symptomatic bullous keratopathy.

METHODS

In three eyes of three patients with painful bullous keratopathy, autologous tragal perichondria were transplanted on the corneal surface with the human amniotic membrane transplanted above. We included an additional three eyes of three patients with painful bullous keratopathy who received amniotic membrane transplantation only to serve as controls. Clinical symptom outcomes were assessed using a visual analogue scale at postsurgical months 1, 3, 5, 7, and 9. In addition, transplanted tragal perichondrium and amniotic membrane complex tissue button obtained from one patient who underwent penetrating keratoplasty was evaluated by immunohistochemical analysis of CD34, vimentin, and alcian blue staining.

RESULTS

All three patients who underwent autologous tragal perichondrium and human amniotic membrane co-transplantation showed improvements in pain and tearing. However, all three patients in the control group experienced aggravation of tearing and no further improvement of pain 3 months after surgery. In addition, one patient in the control group developed premature degradation of the amniotic membrane. Histopathologic and immunohistochemical analysis showed intact surface epithelization and positive CD34, vimentin and alcian blue staining of transplanted tragal perichondria.

CONCLUSIONS

The tragal perichondrium has a high mechanical structural force and high potency due to well-organized epithelization and the presence of mesenchymal stem cells. Autologous tragal perichondrium transplantation may be an effective modality for the management of painful bullous keratopathy.

Engineered cartilage with internal porous high-density polyethylene support from bone marrow stromal cells: A preliminary study in nude mice

Tissue-engineered cartilage may have potential for the construction of clinical implants for the treatment of congenital deformities or post-traumatic defects. However, the lack of seed cells is a challenge, as is the maintenance of ideal shape and size. We have used bone marrow stromal cells (BMSCs) and a pre-shaped polyglycolic acid (PGA)-porous high-density polyethylene composite scaffold to solve these problems. High-density polyethylene was carved into cylindrical rods and encircled with PGA fibres to form scaffolds. Porcine BMSC were seeded into the scaffold and cultured in chondrogenic medium (high-glucose Dulbecco's modified Eagle's medium with 10% (v/v) fetal bovine serum, dexamethasone 40 ng/ml, transforming growth factor-beta1 10 ng/ml, and insulin-like growth factor 50 ng/ml) for 3 weeks in vitro before the cell-scaffold constructs were implanted subcutaneously into nude mice. After 8 weeks of implantation, all specimens in the experimental group had formed mature cartilage around the polyethylene, and the prefabricated shapes and sizes were well maintained. The neoformed cartilage also grew into the pores of the scaffold with a fine interface between them; this gave the whole regenerated composite tissue characteristics similar to those of native cartilage. These results show that it is feasible to construct cartilage using BMSC and PGA-high-density polypropylene scaffolds. This may remove some of the obstacles that have prevented the clinical use of cartilage engineering such as limited volume, deformation, and a limited number of seed cells.

Vascular localization and proliferation in the growing tip of the deer antler

The process of angiogenesis is of interest because of the significant clinical benefits associated with controlling vascular growth. Within the antler, chondrogenesis and antler elongation are occurring at the rate of 1-2 cm per day and thus blood vessels are growing at this same rapid pace. We demonstrate that the process of angiogenesis in the antler is controlled at various tissue locations. The findings clearly differentiate the spatial location of the stem cells that drive chondrogenesis from the proliferation process driving the angiogenesis. Vessels within the lateral dermis contained BrdU-positive cells, suggesting that these vessels were elongating. Within the precartilage region, proliferating vessels were detected in bundles of complex structure evenly distributed throughout this tissue layer. The support cells within these bundles of vessels were detected by staining with alpha-smooth muscle actin, while the endothelial cells were negative. Additionally, the alpha-smooth muscle actin staining was found in association with the cartilage cells of the antler. The marked proliferation of the vascular associated cells in the precartilage region identified this area as a major region of vascular growth in the antler. We propose that within the precartilage region, the most likely mechanisms to explain the observed vascular morphology are that of vascular extension of the existing vessels and intussusceptive angiogenesis or sprouting to generate the small bundles of vessels. Wiley-Liss, Inc.

Alpha-smooth muscle actin expression and structure integrity in chondrogenesis of human mesenchymal stem cells

The expression of alpha-smooth muscle actin (SMA) by human mesenchymal stem cells (hMSCs) during chondrogenesis was investigated by the use of pellet culture. Undifferentiated hMSCs expressed low but detectable amounts of SMA and the addition of transforming growth factor beta1 (TGF-beta1) to the culture medium increased SMA expression in a dose-dependent manner. Differentiation in pellet culture was rapidly induced in the presence of TGF-beta1 and was accompanied by the development of annular layers at the surface of the pellet. These peripheral layers lacked expression of glycosaminoglycan and type II collagen during early differentiation. Progress in differentiation increased the synthesis of glycosaminoglycan and type II collagen and the expression of SMA in these layers. Double-staining for type II collagen and SMA by immunofluorescence demonstrated the differentiation of hMSCs into cells positive for these two proteins. The addition of cytochalasin D, a potent inhibitor of the polymerization of actin microfilaments, caused damage to the structural integrity and surface smoothness of the chondrogenic pellets. The SMA-positive cells in the peripheral layers of the chondrogenic pellets mimic those within the superficial layer of articular cartilage and are speculated to play a major role in cartilage development and maintenance.