Cryopreservation Effect on Proliferative and Chondrogenic Potential of Human Chondrocytes Isolated from Superficial and Deep Cartilage

[Abstract] Objectives: To compare the proliferative and chondrogenic potential of fresh and frozen chondrocytes isolated from superficial and deep articular cartilage biopsies. Materials and Methodology: The study included 12 samples of fresh and frozen healthy human knee articular cartilage. Cell proliferation was tested at 3, 6 and 9 days. Studies of mRNA quantification, protein expression and immunofluorescence for proliferation and chondrogenic markers were performed. Results: Stimulation of fresh and frozen chondrocytes from both superficial and deep cartilage with fetal bovine serum produced an increase in the proliferative capacity compared to the non-stimulated control group. In the stimulated fresh cells group, the proliferative capacity of cells from the deep biopsy was greater than that from cells from the superficial biopsy (0.046 vs 0.028, respectively, p<0.05). There was also a significant difference between the proliferative capacity of superficial zone fresh (0.028) and frozen (0.051) chondrocytes (p<0.05). CCND1 mRNA and protein expression levels, and immunopositivity for Ki67 revealed a higher proliferative capacity for fresh articular chondrocytes from deep cartilage. Regarding the chondrogenic potential, stimulated fresh cells showed higher SOX9 and Col II expression in chondrocytes from deep than from superficial zone (p<0.05, T student test). Conclusions: The highest rate of cell proliferation and chondrogenic potential of fresh chondrocytes was found in cells obtained from deep cartilage biopsies, whereas there were no statistically significant differences in proliferative and chondrogenic capacity between biopsy origins with frozen chondrocytes. These results indicate that both origin and cryopreservation affect the proliferative and chondrogenic potential of chondrocytes.Servizo Galego de Saúde; PS07/84Instituto de Salud Carlos III; CIBER BBN CB06-01-0040Ministerio Ciencia e Innovacion; PLE2009-0144Ministerio Ciencia e Innovación; PI 08/202

Seaweed polysaccharide-based hydrogels used for the regeneration of articular cartilage

This manuscript provides an overview of the in vitro and in vivo studies reported in the literature focusing on seaweed polysaccharides based hydrogels that have been proposed for applications in regenerative medicine, particularly, in the field of cartilage tissue engineering. For a better understanding of the main requisites for these specific applications, the main aspects of the native cartilage structure, as well as recognized diseases that affect this tissue are briefly described. Current available treatments are also presented to emphasize the need for alternative techniques. The following part of this review is centered on the description of the general characteristics of algae polysaccharides, as well as relevant properties required for designing hydrogels for cartilage tissue engineering purposes. An in-depth overview of the most well known seaweed polysaccharide, namely agarose, alginate, carrageenan and ulvan biopolymeric gels, that have been proposed for engineering cartilage is also provided. Finally, this review describes and summarizes the translational aspect for the clinical application of alternative systems emphasizing the importance of cryopreservation and the commercial products currently available for cartilage treatment.Authors report no declarations of interest. Authors thank the Portuguese Foundation for Science and Technology (FCT) for the PhD fellowship of Elena G. Popa (SFRH/BD/64070/2009) and research project (MIT/ECE/0047/2009). The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no REGPOT-CT2012-316331-POLARIS

Painful prosthesis: approaching the patient with persistent pain following total hip and knee arthroplasty.

BACKGROUND: Symptomatic severe osteoarthritis and hip osteoporotic fractures are the main conditions requiring total hip arthroplasty (THA), whereas total knee arthroplasty (TKA) is mainly performed for pain, disability or deformity due to osteoarthritis. After surgery, some patients suffer from "painful prosthesis", which currently represents a clinical problem. METHODS: A systematic review of scientific literature has been performed. A panel of experts has examined the issue of persistent pain following total hip or knee arthroplasty, in order to characterize etiopathological mechanisms and define how to cope with this condition. RESULTS: Four major categories (non infective, septic, other and idiopathic causes) have been identified as possible origin of persistent pain after total joint arthroplasty (TJA). Time to surgery, pain level and function impairment before surgical intervention, mechanical stress following prosthesis implant, osseointegration deficiency, and post-traumatic or allergic inflammatory response are all factors playing an important role in causing persistent pain after joint arthroplasty. Diagnosis of persistent pain should be made in case of post-operative pain (self-reported as VAS ≥3) persisting for at least 4 months after surgery, or new onset of pain (VAS ≥3) after the first 4 months, lasting ≥2 months. Acute pain reported as VAS score ≥7 in patients who underwent TJA should be always immediately investigated. CONCLUSIONS: The cause of pain needs always to be indentified and removed whenever possible. Implant revision is indicated only when septic or aseptic loosening is diagnosed. Current evidence has shown that peri-and/or post-operative administration of bisphosphonates may have a role in pain management and periprosthetic bone loss prevention

In vitro differentiation of human mesenchymal stem cells on Ti6Al4V surfaces

Long-term stability of arthroplasty prosthesis depends on the integration between the bone tissue and the implanted biomaterials, which requires the contribution of osteoblastic precursors and their continuous differentiation into the osteoblastic phenotype. Classically, these interactions are tested in vitro using mesenchymal stem cells (MSCs) isolated and ex vivo expanded from bone marrow aspirates. Human adipose tissue-derived stromal cells (AMSCs) may be a more convenient source of MSCs, according to their abundance and accessibility, but no data are available on their in vitro interactions with hard biomaterials. The aim of this work is to compare the osteogenic potential of human AMSCs and bone marrow-derived MSCs (BMMSCs) and to evaluate their response to Ti6Al4V alloy in terms of adhesion, proliferation and differentiation features, using the human osteosarcoma cell line SaOS-2 for comparison. The overall results showed that AMSCs have the same ability to produce bone matrix as BMMSCs and that Ti6Al4V surfaces exhibit an osteoinductive action on AMSCs, promoting their differentiation into functional osteoblasts and increasing bone formation. In conclusion, adipose tissue is a promising autologous source of osteoblastic cells with important clinical implications for bone tissue engineeri