Age‐related modulation of angiogenesis‐regulating factors in the swine meniscus

Abstract

An in‐depth knowledge of the native meniscus morphology and biomechanics in its different areas is essential to develop an engineered tissue. Meniscus is characterized by a great regional variation in extracellular matrix components and in vascularization. Then, the aim of this work was to characterize the expression of factors involved in angiogenesis in different areas during meniscus maturation in pigs. The menisci were removed from the knee joints of neonatal, young and adult pigs, and they were divided into the inner, intermediate and outer areas. Vascular characterization and meniscal maturation were evaluated by immunohistochemistry and Western blot analysis. In particular, expression of the angiogenic factor Vascular Endothelial Growth Factor (VEGF) and the anti‐angiogenic marker Endostatin (ENDO) was analysed, as well as the vascular endothelial cadherin (Ve‐CAD). In addition, expression of Collagen II (COLL II) and SOX9 was examined, as markers of the fibro‐cartilaginous differentiation. Expression of VEGF and Ve‐CAD had a similar pattern in all animals, with a significant increase from the inner to the outer part of the meniscus. Pooling the zones, expression of both proteins was significantly higher in the neonatal meniscus than in young and adult menisci. Conversely, the young meniscus revealed a significantly higher expression of ENDO compared to the neonatal and adult ones. Analysis of tissue maturation markers showed an increase in COLL II and a decrease in SOX9 expression with age. These preliminary data highlight some of the changes that occur in the swine meniscus during growth, in particular the ensemble of regulatory factors involved in angiogenesis.

Evidence of vasculature and chondrocyte to osteoblast transdifferentiation in craniofacial synovial joints: Implications for osteoarthritis diagnosis and therapy

“…28,31 As a control, we compared all vascular transcripts in TMJ tissues relative to donor-matched vascularized knee meniscus tissue. [45][46][47][48] Similar to our in vivo data, the expression of endothelial cell markers (CD31, VE-cadherin) 44,49 was significantly upregulated in the TMJ fibrocartilage, condylar cartilage and disk in comparison to the knee meniscus tissue ( Figure 2L), while the mural cell marker (Pdgfrβ) 50,51 was upregulated in the TMJ condylar cartilage in comparison to knee meniscus ( Figure 2M). The expression of arterial vessel markers (Ephrinb2, α-SMA) 43,52,53 (Figure 2N) and the venous marker (Ephb4) 42,43,53 (Figure 2O) were all significantly upregulated in the TMJ fibrocartilage (SZ) and the condylar cartilage (PZ, MZ, HZ), suggesting that both arteries and veins span throughout all of the cellular zones in the TMJ mandibular condyle and also in the TMJ disc.…”

“…We isolated RNA from miniature pig TMJ fibrocartilage (FC) containing the SZ, condylar cartilage (CC) harboring the PZ, MZ and HZ, subchondral bone (SB) harboring the EZ, and the TMJ disk . As a control, we compared all vascular transcripts in TMJ tissues relative to donor‐matched vascularized knee meniscus tissue . Similar to our in vivo data, the expression of endothelial cell markers ( CD31, VE‐cadherin ) was significantly upregulated in the TMJ fibrocartilage, condylar cartilage and disk in comparison to the knee meniscus tissue (Figure L), while the mural cell marker ( Pdgfrβ ) was upregulated in the TMJ condylar cartilage in comparison to knee meniscus (Figure M).…”

“…To confirm the presence of vasculature within the TMJ mandibular condylar cartilage in miniature pigs, we characterized two cell types found in functional blood vessels, including endothelial cells (ECs) and vascular mural cells, which comprise pericytes and vascular smooth muscle cells (vSMCs) 42,43 (Figure 2). To determine the distribution of endothelial cells, which form the inner vessel wall, and mural cells, which surround the endothelial cell tube for structural support and regulation of diameter and blood flow, we examined the presence of CD31 + ECs 44 and alpha-smooth muscle actin (α-SMA) + vSMCs by immunohistochemistry (Figure 2A meniscus has been reported to contain a vascular supply [45][46][47][48] and was used as positive control tissue for confirming CD31 + ECs and α-SMA + vSMCs immunostainings ( Figure 2I-K). Disc α-SMA + cells were associated with low expression CD31 + ECs (Figure 2A-C).…”

Impacts of maturation on the micromechanics of the meniscus extracellular matrix

“…In addition to the reduction in cell density (Ionescu et al, 2011), decrease in vascularity (King, 1990) and alteration in cell metabolism (Bland and Ashhurst, 1996), one salient change is the alteration of the ECM modulus and collagen fiber alignment (Qu et al, 2015). Maturation-associated ECM structural changes can increase the impedance of blood vessel infiltration and cell migration that is critical for self-healing (Di Giancamillo et al, 2017). Therefore, understanding the impact of maturation on the local structure and mechanical properties of the meniscus ECM will provide new insights into the biomechanical cues and self-repair mechanisms of native meniscus, and will assist the design of novel tissue engineering strategies (Qu et al, 2018).…”

Cortical Granule Distribution and Expression Pattern of Genes Regulating Cellular Component Size, Morphogenesis, and Potential to Differentiation are Related to Oocyte Developmental Competence and Maturational Capacity In Vivo and In Vitro

“…However, the SOX9 gene (SRY-box transcription factor 9) is associated with the processes related to sex differentiation-its activation of transcription and gonadal development [61,62]. It also has a role in skeletal development and chondrogenesis [63][64][65]. The increase in the expression of this gene may indicate the maturation of gametes from the female gonads.…”