Intra-articular Injection of Bevacizumab Enhances Bone Marrow Stimulation-Mediated Cartilage Repair in a Rabbit Osteochondral Defect Model

TIPE2 gene transfer ameliorates aging-associated osteoarthritis in a progeria mouse model by reducing inflammation and cellular senescence

Osteoarthritis (OA) pain is often associated with the expression of tumor necrosis factor alpha (TNF-α), suggesting that TNF-α is one of the main contributing factors that cause inflammation, pain, and OA pathology. Thus, inhibition of TNF-α could potentially improve OA symptoms and slow disease progression. Anti-TNF-α treatments with antibodies, however, require multiple treatments and cannot entirely block TNF-α. TNF-α-induced protein 8-like 2 (TIPE2) was found to regulate the immune system's homeostasis and inflammation through different mechanisms from anti-TNF-α therapies. With a single treatment of adeno-associated virus (AAV)-TIPE2 gene delivery in the accelerated aging Zmpste24-/- (Z24-/-) mouse model, we found differences in Safranin O staining intensity within the articular cartilage (AC) region of the knee between TIPE2-treated mice and control mice. The glycosaminoglycan content (orange-red) was degraded in the Z24-/- cartilage while shown to be restored in the TIPE2-treated Z24-/- cartilage. We also observed that chondrocytes in Z24-/- mice exhibited a variety of senescent-associated phenotypes. Treatment with TIPE2 decreased TNF-α-positive cells, β-galactosidase (β-gal) activity, and p16 expression seen in Z24-/- mice. Our study demonstrated that AAV-TIPE2 gene delivery effectively blocked TNF-α-induced inflammation and senescence, resulting in the prevention or delay of knee OA in our accelerated aging Z24-/- mouse model.

Composite Hydrogel Containing Collagen-Modified Polylactic Acid-Hydroxylactic Acid Copolymer Microspheres Loaded with Tetramethylpyrazine Promotes Articular Cartilage Repair

Articular cartilage defects pose a significant challenge due to the limited self-healing ability of cartilage. However, traditional techniques face limitations including autologous chondrocyte expansion issues. This study aims to investigate the effects of the polylactic acid-glycolic acid (PLGA) and collagen-surface modified polylactic acid-glycolic acid (CPLGA) microspheres loaded with tetramethylpyrazine (TMP) on two cell types and the regeneration potential of articular cartilage. CPLGA microspheres are prepared by Steglich reaction and characterized. They evaluated the effect of TMP-loaded microspheres on HUVECs (Human Umbilical Vein Endothelial Cells) and examined the compatibility of blank microspheres with BMSCs (Bone marrow mesenchymal stromal cells) and their potential to promote cartilage differentiation. Subcutaneous implant immune tests and cartilage defect treatment are conducted to assess biocompatibility and cartilage repair potential. The results highlight the efficacy of CPLGA microspheres in promoting tissue regeneration, attributed to improved hydrophilicity and collagen-induced mitigation of degradation. Under hypoxic conditions, both CPLGA and PLGA TMP-loaded microspheres exhibit inhibitory effects on HUVEC proliferation, migration, and angiogenesis. Notably, CPLGA microspheres show enhanced compatibility with BMSCs, facilitating chondrogenic differentiation. Moreover, the CPLGA microsphere-composite hydrogel exhibits potential for cartilage repair by modulating angiogenesis and promoting BMSC differentiation.

Investigating the Potential of Multilineage Differentiating Stress-Enduring Cells for Osteochondral Healing

OBJECTIVE

Multilineage differentiating stress-enduring (Muse) cells, a pluripotent stem cell subset of mesenchymal stem cells (MSCs), have shown promise for various tissue repairs due to their stress tolerance and multipotent capabilities. We aimed to investigate the differentiation potential in vitro, the dynamics in vivo, and the reparative contribution of Muse cells to osteochondral lesions.

DESIGN

Labeled MSCs were cultured and sorted into Muse and non-Muse (MSCs without Muse cells) groups. These cells were then formed into spheroids, and chondrogenic differentiation was assessed in vitro. Twenty-one immunocompromised mice were used as the in vivo models of osteochondral lesions. Live imaging, macroscopic evaluation, and histological and immunohistochemical analyses were conducted at the 4- and 8-week time points.

RESULTS

Muse cell spheroids were formed, which were larger and stained more intensely with toluidine blue than non-Muse spheroids, indicating better chondrogenic differentiation. Live imaging confirmed luminescence in all 4-week model knees, but only in a few knees at 8 weeks, suggesting cell persistence. Macroscopically and histologically, no significant differences were observed between the Muse and non-Muse groups at 4 and 8 weeks; however, both groups showed better cartilage repair than that of the vehicle group at 8 weeks. No collagen type II generation was observed in the repaired tissues.

CONCLUSION

The implantation of the spheroids of Muse and non-Muse cells resulted in better healing of osteochondral lesions than that of the controls, and Muse cells had a higher chondrogenic differentiation potential in vitro than non-Muse cells.

HWJMSC-EVs promote cartilage regeneration and repair via the ITGB1/TGF-β/Smad2/3 axis mediated by microfractures

The current first-line treatment for repairing cartilage defects in clinical practice is the creation of microfractures (MF) to stimulate the release of mesenchymal stem cells (MSCs); however, this method has many limitations. Recent studies have found that MSC-derived extracellular vesicles (MSC-EVs) play an important role in tissue regeneration. This study aimed to verify whether MSC-EVs promote cartilage damage repair mediated by MFs and to explore the repair mechanisms. In vitro experiments showed that human umbilical cord Wharton's jelly MSC-EVs (hWJMSC-EVs) promoted the vitality of chondrocytes and the proliferation and differentiation ability of bone marrow-derived MSCs. This was mainly because hWJMSC-EVs carry integrin beta-1 (ITGB1), and cartilage and bone marrow-derived MSCs overexpress ITGB1 after absorbing EVs, thereby activating the transforming growth factor-β/Smad2/3 axis. In a rabbit knee joint model of osteochondral defect repair, the injection of different concentrations of hWJMSC-EVs into the joint cavity showed that a concentration of 50 µg/ml significantly improved the formation of transparent cartilage after MF surgery. Extraction of regenerated cartilage revealed that the changes in ITGB1, transforming growth factor-β, and Smad2/3 were directly proportional to the repair of regenerated cartilage. In summary, this study showed that hWJMSC-EVs promoted cartilage repair after MF surgery.

Intra-articular injection of ascorbic acid enhances microfracture-mediated cartilage repair

Previous studies have confirmed that ascorbic acid (AA) can promote cartilage repair and improve cartilage differentiation in bone marrow mesenchymal stem cells. However, the use of microfracture (MFX) combined with AA to repair cartilage damage has not been studied. This study established a rabbit animal model and treated cartilage injury with different concentrations of AA combined with MFX. Macroscopic observations, histological analysis, immunohistochemical analysis and reverse transcription quantitative polymerase chain reaction analysis of TGF-β, AKT/Nrf2, and VEGF mRNA expression were performed. The results showed that intra-articular injection of AA had a positive effect on cartilage repair mediated by microfractures. Moreover, 10 mg/ml AA was the most effective at promoting cartilage repair mediated by microfractures. Intra-articular injection of AA promoted the synthesis of type II collagen and the formation of glycosaminoglycans by downregulating the mRNA expression of TGF-β and VEGF. In summary, this study confirmed that AA could promote cartilage repair after MFX surgery.

What is the Effect of Bevacizumab on Cartilage and Synovium in a Rabbit Model of Hemophilic Arthropathy?

BACKGROUND

Hemophilic arthropathy can cause recurrent hemarthroses and severe damage to the synovium and articular cartilage. Previous studies have shown that vascular endothelial growth factor (VEGF) plays an essential role in neoangiogenesis. Bevacizumab, a monoclonal VEGF inhibitor, is used clinically to prevent angiogenesis. However, its effects on hemophilic arthropathy are unknown.

QUESTIONS/PURPOSES

Using a hemophilic arthropathy rabbit model, we asked: Does an intra-articular injection of bevacizumab (1) inhibit VEGF, (2) decrease signal intensity in dynamic contrast-enhanced MRI (DCE-MRI) as an assessment of capillary permeability and neoangiogenesis, (3) reduce cartilage damage, (4) reduce synovial changes, and (5) affect macroscopic changes during the development of hemophilic arthropathy?

METHODS

Twenty-five male New Zealand rabbits were divided into four groups. Eight knees from four rabbits were used as the control group. We used an established animal model for hemophilic arthropathy in the remaining 21 rabbits. Animals were assigned randomly to three groups with seven rabbits in each group. One group was used to establish mild arthropathy, and the other two were used to establish severe arthropathy. Autologous blood from the rabbits' ears was injected into the right and left knees twice per week for 8 weeks to represent mild arthropathy and for 16 weeks to represent severe arthropathy. In the mild arthropathy group, bevacizumab was injected into the right knee once every 2 weeks. Bevacizumab was injected into the right knee of rabbits in one of the severe arthropathy groups once every 2 weeks for 16 weeks, and intra-articular bevacizumab injections were administered to the right knees of rabbits in the other severe arthropathy group once every 2 weeks after the eighth week. An equal volume of 0.9% saline was injected into the left knee of rabbits in all arthropathy groups. To explore the efficacy of bevacizumab, joint diameters were quantitatively measured, and cartilage and synovial changes were examined. Degeneration of articular cartilage was evaluated with the semiquantitative Osteoarthritis Research Society International grading system. Synovial damage was analyzed with a semiquantitative microscopic scoring system. In addition, we evaluated perfusion and angiogenesis using DCE-MRI (quantitative signal intensity changes). Immunohistochemical testing was used to measure VEGF levels (analyzed by Western blotting).

RESULTS

Intra-articular bevacizumab treatment inhibited VEGF in our rabbit model of hemophilic arthropathy. VEGF protein expression levels were lower in the mild arthropathy group that received intra-articular bevacizumab (0.89 ± 0.45) than the mild arthropathy control group (1.41 ± 0.61) (mean difference -0.52 [95% CI -0.898 to -0.143]; p = 0.02). VEGF levels were lower in the severe arthropathy group that received treatment for 16 weeks (0.94 ± 0.27) than in the control knees (1.49 ± 0.36) (mean difference -0.55 [95% CI -0.935 to -0.161]; p = 0.01). In the severe arthropathy group, the Osteoarthritis Research Society International score indicating cartilage damage was lower in the group that received intra-articular bevacizumab treatment from the beginning than in the control group (median 17 [range 13 to 18] versus 18 [range 17 to 20]; difference of medians 1; p = 0.02). Additionally, the scores indicated synovial damage was lower in the group that received intra-articular bevacizumab treatment from the beginning than the control group (median 5 [range 4 to 9] versus 9 [range 8 to 12]; difference of medians 4; p = 0.02). The mean of mean values for signal intensity changes was higher in the nontreated severe groups than in the group of healthy knees. The signal intensity changes were higher in the severe arthropathy control groups (Groups BC and CC) (median 311.6 [range 301.4 to 361.2] and 315.1 [range 269.7 to 460.4]) than in the mild arthropathy control group (Group AC) (median 234.1 [range 212.5 to 304.2]; difference of medians 77.5 and 81, respectively; p = 0.02 and p = 0.04, respectively). In the severe arthropathy group, discoloration caused by hemosiderin deposition in the cartilage and synovium was more pronounced than in the mild arthropathy group. In the severe arthropathy group treated with intra-articular bevacizumab, joint diameters were smaller than in the control group (Group BT median 12.7 mm [range 12.3 to 14.0] versus Group BC median 14.0 mm [range 13.1 to 14.5]; difference of medians 1.3 mm; p = 0.02).

CONCLUSION

Hemarthrosis damages the synovial tissues and cartilage in the knees of rabbits, regardless of whether they are treated with intra-articular bevacizumab. However, intra-articular injection of bevacizumab may reduce cartilage and synovial damage in rabbits when treatment is initiated early during the development of hemophilic arthropathy.

CLINICAL RELEVANCE

If the findings in this study are replicated in larger-animal models that consider the limitations of our work, then a trial in humans might be appropriate to ascertain whether intra-articular injection of bevacizumab could reduce cartilage damage and synovial changes in patients with hemophilia whose hemarthroses cannot otherwise be controlled.

Recent development in multizonal scaffolds for osteochondral regeneration

Osteochondral (OC) repair is an extremely challenging topic due to the complex biphasic structure and poor intrinsic regenerative capability of natural osteochondral tissue. In contrast to the current surgical approaches which yield only short-term relief of symptoms, tissue engineering strategy has been shown more promising outcomes in treating OC defects since its emergence in the 1990s. In particular, the use of multizonal scaffolds (MZSs) that mimic the gradient transitions, from cartilage surface to the subchondral bone with either continuous or discontinuous compositions, structures, and properties of natural OC tissue, has been gaining momentum in recent years. Scrutinizing the latest developments in the field, this review offers a comprehensive summary of recent advances, current hurdles, and future perspectives of OC repair, particularly the use of MZSs including bilayered, trilayered, multilayered, and gradient scaffolds, by bringing together onerous demands of architecture designs, material selections, manufacturing techniques as well as the choices of growth factors and cells, each of which possesses its unique challenges and opportunities.

Subchondral Drilling Independent of Drill Hole Number Improves Articular Cartilage Repair and Reduces Subchondral Bone Alterations Compared With Debridement in Adult Sheep

BACKGROUND

Subchondral drilling is an established marrow stimulation technique for small cartilage defects, but whether drilling is required at all and if the drill hole density affects repair remains unclear.

HYPOTHESES

Osteochondral repair is improved when the subchondral bone is perforated by a higher number of drill holes per unit area, and drilling is superior to defect debridement alone.

STUDY DESIGN

Controlled laboratory study.

METHODS

Rectangular full-thickness chondral defects (4 × 8 mm) were created in the trochlea of adult sheep (N = 16), debrided down to the subchondral bone plate without further treatment as controls (no treatment; n = 7) or treated with either 2 or 6 (n = 7 each) subchondral drill holes (diameter, 1.0 mm; depth, 10.0 mm). Osteochondral repair was assessed at 6 months postoperatively by standardized (semi-)quantitative macroscopic, histological, immunohistochemical, biochemical, and micro-computed tomography analyses.

RESULTS

Compared with defect debridement alone, histological overall cartilaginous repair tissue quality (P = .025) and the macroscopic aspect of the adjacent cartilage (P≤ .032) were improved after both drilling densities. Only drilling with 6 holes increased type 2 collagen content in the repair tissue compared with controls (P = .038). After debridement, bone mineral density was significantly decreased in the subchondral bone plate (P≤ .015) and the subarticular spongiosa (P≤ .041) compared with both drilling groups. Debridement also significantly increased intralesional osteophyte sectional area compared with drilling (P≤ .034). No other differences in osteochondral repair existed between subchondral drilling with 6 or 2 drill holes.

CONCLUSION

Subchondral drilling independent of drill hole density significantly improves structural cartilage repair compared with sole defect debridement of full-thickness cartilage defects in sheep after 6 months. Subchondral drilling also leads to a better reconstitution of the subchondral bone compartment below the defects. Simultaneously, drilling reduced the formation of intralesional osteophytes caused by osseous overgrowth compared with debridement.

CLINICAL RELEVANCE

These results have important clinical implications, as they support subchondral drilling independent of drill hole number but discourage debridement alone for the treatment of small cartilage defects. Clinical studies are warranted to further quantify the effects of subchondral drilling in similar settings.

Microenvironmentally optimized 3D-printed TGFβ-functionalized scaffolds facilitate endogenous cartilage regeneration in sheep

Clinically, microfracture is the most commonly applied surgical technique for cartilage defects. However, an increasing number of studies have shown that the clinical improvement remains questionable, and the reason remains unclear. Notably, recent discoveries revealed that signals from regenerated niches play a critical role in determining mesenchymal stem cell fate specification and differentiation. We speculate that a microenvironmentally optimized scaffold that directs mesenchymal stem cell fate will be a good therapeutic strategy for cartilage repair. Therefore, we first explored the deficiency of microfractures in cartilage repair. The microfracture not only induced inflammatory cell aggregation in blood clots but also consisted of loose granulation tissue with increased levels of proteins related to fibrogenesis. We then fabricated a functional cartilage scaffold using two strong bioactive cues, transforming growth factor-β3 and decellularized cartilage extracellular matrix, to modulate the cell fate of mesenchymal stem cells. Additionally, poly(ε-caprolactone) was also coprinted with extracellular matrix-based bioinks to provide early mechanical support. The in vitro studies showed that microenvironmentally optimized scaffolds exert powerful effects on modulating the mesenchymal stem cell fate, such as promoting cell migration, proliferation and chondrogenesis. Importantly, this strategy achieved superior regeneration in sheep via scaffolds with biomechanics (restored well-organized collagen orientation) and antiapoptotic properties (cell death-related genes were also downregulated). In summary, this study provides evidence that microenvironmentally optimized scaffolds improve cartilage regeneration in situ by regulating the microenvironment and support further translation in human cartilage repair. STATEMENT OF SIGNIFICANCE: Although microfracture (MF)-based treatment for chondral defects has been commonly used, critical gaps exist in understanding the biochemistry of MF-induced repaired tissue. More importantly, the clinically unsatisfactory effects of MF treatment have prompted researchers to focus on tissue engineering scaffolds that may have sufficient therapeutic efficacy. In this manuscript, a 3D printing ink containing cartilage tissue-specific extracellular matrix (ECM), methacrylate gelatin (GelMA), and transforming growth factor-β3 (TGF-β3)-embedded polylactic-coglycolic acid (PLGA) microspheres was coprinted with poly(ε-caprolactone) (PCL) to fabricate tissue engineering scaffolds for chondral defect repair. The sustained release of TGF-β3 from scaffolds successfully directed endogenous stem/progenitor cell migration and differentiation. This microenvironmentally optimized scaffold produced improved tissue repair outcomes in the sheep animal model, explicitly guiding more organized neotissue formation and therefore recapitulating the anisotropic structure of native articular cartilage. We hypothesized that the cell-free scaffolds might improve the clinical applicability and become a new therapeutic option for chondral defect repair.