Is arthroscopic videotape a reliable tool for describing early joint tissue pathology of the knee?

BACKGROUND: The aim of this study was to assess the reliability of the videotape scoring system collected during knee arthroscopy for meniscal tears, and to test the consistency with intra-operative findings. METHODS: Fifty-seven patients undergoing arthroscopic treatment of meniscal tears were included in the analysis. The cartilage damage was assessed intra-operatively, at six sites, using the Outerbridge scoring system. The meniscal tears were graded according to the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) classification. The presence of synovial inflammation was scored, at four different sites, according to the macro-score method. The total cartilage, meniscal and synovial scores were calculated for each knee by the sum of the maximum grade of the lesions at each anatomic site. In order to assess the reliability of the arthroscopic scoring system, the videotapes recorded during the arthroscopy were reviewed by two independent observers one year after the surgery and compared with the scores completed by the surgeon during the operation. RESULTS: The total cartilage score showed substantial inter-rater and intra-rater reliability, and moderate consistency with the intra-operative score provided by the surgeon. The total meniscal score showed substantial inter-rater and intra-rater reliability, and good consistency with the intra-operative findings. The total synovial score showed substantial inter-rater agreement, substantial intra-rater reliability, and moderate consistency with intra-operative findings. CONCLUSIONS: The videotape scoring system provided a reliable and reproducible system for recording the intra-operative state of the whole joint pathology in patients undergoing arthroscopic treatment of meniscal tears.

Increased Plin2 expression in human skeletal muscle is associated with sarcopenia and muscle weakness.

Human aging is associated with a progressive loss of muscle mass and strength and a concomitant fat accumulation in form of inter-muscular adipose tissue, causing skeletal muscle function decline and immobilization. Fat accumulation can also occur as intra-muscular triglycerides (IMTG) deposition in lipid droplets, which are associated with perilipin proteins, such as Perilipin2 (Plin2). It is not known whether Plin2 expression changes with age and if this has consequences on muscle mass and strength. We studied the expression of Plin2 in the vastus lateralis (VL) muscle of both healthy subjects and patients affected by lower limb mobility limitation of different age. We found that Plin2 expression increases with age, this phenomenon being particularly evident in patients. Moreover, Plin2 expression is inversely correlated with quadriceps strength and VL thickness. To investigate the molecular mechanisms underpinning this phenomenon, we focused on IGF-1/p53 network/signalling pathway, involved in muscle physiology. We found that Plin2 expression strongly correlates with increased p53 activation and reduced IGF-1 expression. To confirm these observations made on humans, we studied mice overexpressing muscle-specific IGF-1, which are protected from sarcopenia. These mice resulted almost negative for the expression of Plin2 and p53 at two years of age. We conclude that fat deposition within skeletal muscle in form of Plin2-coated lipid droplets increases with age and is associated with decreased muscle strength and thickness, likely through an IGF-1- and p53-dependent mechanism. The data also suggest that excessive intramuscular fat accumulation could be the initial trigger for p53 activation and consequent loss of muscle mass and strength.

Enhanced osteoblastogenesis of adipose-derived stem cells on spermine delivery via ß-catenin activation.

The molecular mechanisms underlying spermine osteo-inductive activity on human adipose-derived stem cells (ASCs) grown in 3-dimensional (3D) cultures were investigated. Spermine belongs to the polyamine family, naturally occurring, positively charged polycations that are able to control several cellular processes. Spermine was used at a concentration close to that found in platelet-rich plasma (PRP), an autologous blood product containing growth and differentiation factors, which has recently become popular in in vitro and in vivo bone healing and engineering. Adipose tissue was surgically obtained from the hypodermis of patients undergoing hip arthroplasty. Patient age negatively affected both ASC yield and ASC ability to form 3D constructs. ASC 3D cultures were seeded in either non differentiating or chondrogenic conditions, with or without the addition of 5 µM spermine to evaluate its osteogenic potential across 1, 2, and 3 weeks of maturation. Osteogenic medium was used as a reference. The effects of the addition of spermine on molecular markers of osteogenesis, at both gene and protein level, and mineralization were evaluated. The effects of spermine were temporally defined and responsible for the progression from the early to the mature osteoblast differentiation phases. Spermine initially promoted gene and protein expression of Runx-2, an early marker of the osteoblast lineage; then, it increased ß-catenin expression and activation, which led to the induction of Osterix gene expression, the mature osteoblast commitment factor. The finding that spermine induces ASC to differentiate toward mature osteoblasts supports the use of these easily accessible mesenchymal stem cells coupled with PRP for orthopedic applications.