Abstract
Articular cartilage regeneration is insufficient to restore sports injuries or defects that can occur from trauma. Treatment options for cartilage repair include autologous chondrocyte implantation (ACI) by isolation, expansion, and reimplantation of healthy donor chondrocytes. Chondrocyte expansion onto 2D substrates leads to dedifferentiation and loss of the cellular phenotype. We aimed to overcome the state of dedifferentiation by biochemical stimuli with platelet derivatives such as platelet-rich plasma (PRP) and hyperacute serum (HAS) to achieve sufficient cell numbers in combination with variable oxygen tension. Human articular chondrocytes from osteoarthritic (OA) cartilage chondrocytes were switched from 10% FCS supplementation to either 10% PRP or 10% HAS after initial passaging for further experiments under normoxic (20% O2) or hypoxic (1% O2) conditions. An XTT assay measured the effect of PRP or HAS on the cell proliferation at 3, 6, and 9 days. The chondrogenic redifferentiation potential of dedifferentiated chondrocytes was determined with reverse transcriptase quantitative real-time PCR for markers of expression for type II collagen (COL2A1), type I collagen (COL1A1), and matrix metalloproteinases MMP3, matrix metalloproteinase 13 (MMP13) at 24 and 72 h. Measured protein levels of 100% PRP or HAS by multiplex quantification revealed basic fibroblast growth factor, G-CSF, and PDGF were significantly higher in PRP than in HAS (p < 0.05) but LEPTIN levels did not differ. The quantified protein levels did not differ when isolated from same donors at a different time. Chondrocyte proliferation indicated that supplementation of 10% HAS enhanced the proliferation rate compared to 10% PRP or 10% FCS at 6 and 9 days significantly (p < 0.05). mRNA levels for expression of COL1A1 were significantly downregulated (p < 0.05) when cultured with 10% PRP than 10% HAS or 10% FCS under normoxic/hypoxic conditions. COL2A1 was significantly upregulated (p < 0.05) in PRP than 10% HAS or 10% FCS. MMP3 expression was downregulated after 72 h under all conditions. MMP13 was upregulated with 10% PRP at both 24 and 72 h but significantly downregulated under hypoxia (1% O2) for all circumstances. While HAS has its effect on chondrocyte proliferation, PRP enhances both proliferation and redifferentiation of dedifferentiated chondrocytes. PRP can replace standard usage of FCS for chondrogenic priming and expansion as implications for clinical use such as ACI procedures.
Highlights
Articular cartilage is an avascular, alymphatic, aneural tissue that functions as a lubricating and load-bearing surface of the joint limited by the regenerative potential of its individual cell type, the chondrocyte
hyperacute serum (HAS) and platelet-rich plasma (PRP) isolated at 0 and 6 weeks from six individual donors revealed that isolation time dissimilarities in the release kinetics of platelet-derived growth factor BB (PDGF-BB), G-CSF, leptin, and basic fibroblast growth factor (bFGF) (Figures 1E–H) were not significantly different among the individual donors (p = 0.1797, p = 0.4848, p = 0.5043, and p = 0.5887, respectively)
PDGF-BB has been able to enhance chondrocyte proliferation through the extracellular signal-regulated kinase 1/2 pathway (Xiao et al, 2014) and is active inhibitors of the IL-1βmediated activation of NF-kB and apoptosis in chondrocytes (Montaseri et al, 2011). bFGF is believed to be a key regulator of maintaining the chondrocyte phenotype during expansion. bFGF has a catabolic effect on dedifferentiation by upregulating the matrix metalloproteinases MMP1, matrix metalloproteinase 13 (MMP13) and downregulating aggrecan, collagen II in human OA chondrocytes (OAC) (Nummenmaa et al, 2015)
Summary
Articular cartilage is an avascular, alymphatic, aneural tissue that functions as a lubricating and load-bearing surface of the joint limited by the regenerative potential of its individual cell type, the chondrocyte. Autologous chondrocyte implantation (ACI) predominantly treats focal chondral defects ≥3–4 cm covered by periosteum layer (ACI-P) (Minas, 2001), collagen type I/III membrane (ACI-C) (Niemeyer et al, 2008), or the use of fibrin or hyaluronan matrix-assisted chondrocyte implantation (ACI-M/MACI) (Nehrer et al, 2008). ACI is a technique that involves isolation of autologous articular chondrocytes from a non-load-bearing site of the joint by enzymatic digestion, expanded, and implanted into the defect site (Peterson et al, 2000). Isolation of chondrocytes from the tissue biopsy involves enzymatic digestion which further dissociates the chondrocytes from their pericellular microenvironment (chondrons) that dedifferentiates the cells by losing their native chondrogenic phenotype (Vonk et al, 2014). Despite tremendous clinical success with ACI, there still exist areas for continued development of efficient protocols toward priming hyaline cartilage formation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
