BackgroundDespite no international consensus on the diagnostic criteria for sarcopenia, low lean mass, muscle strength, and physical function are important risk factors for disability, frailty, and mortality in older individuals, as well as in a wide range of patients with muscle loss. Here, we provide a population‐based reference material of total and regional lean body mass, muscle strength/power parameters, and physical function in a healthy cohort of Danish men and women across the lifespan.MethodsVolunteers aged 20–93 years from the Copenhagen City Heart Study were invited to establish a Danish reference material (Copenhagen Sarcopenia Study) on lean mass characteristics [appendicular lean mass (ALM), iDXA, GE Lunar], muscle function [handgrip strength (HGS), Jamar dynamometer and leg extension power (LEP), Nottingham Power Rig], and physical function [30 s sit‐to‐stand test (STS), 10‐m maximal and habitual gait speed (GS)].ResultsA total of 1305 participants [729 women (age: 56.4 ± 18.9 years, height: 1.66 ± 0.01 m, body mass index: 24.6 ± 4.3 kg/m2 and 576 men, age: 57.0 ± 17.5 years, height: 1.80 ± 0.07 m, body mass index: 26.0 ± 3.9 kg/m2] completed all measurements and were included in the present analysis. Lean mass characteristics (TLM, ALM, and ALM/h2) decreased with increasing age in both men and women (P < 0.001). Men demonstrated larger absolute and relative total ALM and higher HGS and LEP compared with women at all age intervals (P < 0.001). HGS and LEP decreased progressively with age in both men and women (P < 0.01); 30 s STS performance, habitual GS, and maximal GS decreased at an accellerated rate of decline with increasing age in both men and women (P < 0.001). Habitual GS was reduced in men and women aged ≥70 years, while maximal GS was reduced from the age of ≥60 years compared with young adults (P < 0.001). Regardless of sex, 30 s STS was reduced from the age of ≥50 years compared with the young reference group (P < 0.001)ConclusionsWhile the power‐based measurements (LEP and 30 s STS) started to decline already at age +50 years, less power‐based parameters (GS and HGS) and lean mass characteristics (TLM, ALM, and ALM/h2) remained unaltered until after the age of +70 years. Notably, the cut‐off thresholds derived in the present study differed from earlier reference data, which underlines the importance of obtaining updated and local reference materials.

The NSP-PCL scaffold demonstrated higher in vitro expression of chondrogenic markers and had higher in vivo histological scores compared to the Chondro-Gide scaffold. The improved chondrocytic differentiation can potentially produce more hyaline cartilage during clinical cartilage repair. It appears to be a suitable cell-free implant for hyaline cartilage repair and could provide a less costly and more effective treatment option than the Chondro-Gide scaffold with cells.

Purpose This study investigates the effect of cell seeding density on cartilage repair in matrix-assisted chondrocyte implantation in vitro and in vivo. Methods In vitro: Four different cell seeding densities of human chondrocytes were seeded onto a porous methoxypolyethylene glycol-polylactic-co-glycolic acid scaffold (MPEG-PLGA) polymer scaffold ASEED TM (1.2 9 10 6 , 4.0 9 10 6 , 1.2 9 10 7 and 2.0 9 10 7 cells/cm 3 ). The cartilage repair response was evaluated by relative gene expression of the chondrogenic markers sox9, collagen types I, II and X, and aggrecan, total DNA content and sulphated glycosaminoglycan synthesis. In vivo: Using a New Zealand white rabbit intercondylar osteochondral defect model, three different cell seeding densities (1.2 9 10 6 , 4.0 9 10 6 and 1.2 9 10 7 cells/cm 3 ) were tested with an empty scaffold as control. The cartilage repair response was evaluated using O'Driscoll score. Results In vitro: A significant difference (p \ 0.05) in total DNA content was found at day 2 but not at day 7. The low cell seeding densities yielded the highest GAG content (p \ 0.001) at day 7. Collagen type I was highest (p \ 0.01) at the lowest density at day 7. In vivo: No significant difference was found between the 4 groups. Conclusions No positive effect on cartilage repair was found using increased cell seeding density. Level of evidence Controlled experimental study, Level II.

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