RESPONSE OF KNEE CARTILAGE T2 RELAXATION TIMES TO 21-DAYS OF 6°HEAD-DOWN-TILT BED REST COMBINED WITH EXERCISE AND NUTRITION COUNTERMEASURES

Anna-Maria Liphardt, Elie-Tino Godonou, Annegret Mündermann, Maren Dreiner, Frank Zaucke, W. Wirth, A. Wisser, S. Maschek, Felix Eckstein, G Schett, Anja Niehoff

Publikation: Beitrag in Buch/Bericht/KonferenzbandKonferenzbeitrag - Abstract in KonferenzbandForschungBegutachtung

Abstract

Abstract:
Purpose: While mechanical stress is known to influence the regulation of musculoskeletal tissue
metabolism, the effects of immobilization on articular cartilage health in healthy individuals are not well
understood. Magnetic resonance imaging (MRI) T2 relaxation times (T2Me) of articular cartilage are
qualitative measures of cartilage quality where longer T2Me corresponds to poorer tissue quality. This
study aims to investigate the effects of serial 21-days of 6°head-down-tilt bed rest (HDT-BR) periods
combined with nutrition and exercise countermeasures on T2Me of the tibiofemoral articular cartilage
in healthy male individuals.
Methods: The ESA-funded “Medium duration nutrition and vibration exercise” (MNX) -study was
conducted in a cross-over design with three campaigns (C1 - C3, each 7 days of baseline data collection
(BDC), 21 days of HDT-BR, and 7 days of recovery (R+)) interspersed with 4-month wash out periods
(total duration: 12 months). HDT-BR was applied alone (control, CON) or in combination with resistive
vibration exercise (RVE) [4] or RVE + nutrition countermeasure (whey & bicarbonate supplementation,
NeX) in 12 healthy male subjects (age, 34.2 ± 8.3 years; body mass index, 22.4 ± 1.7 kg/m²). T2
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sequences of the femur and tibia were obtained at BDC-7, HDT21 and R+6 of each campaign. MRI data
were segmented by a blinded, independent service provider (Chondrometrics GmbH, Freilassing,
Germany) and T2Me computed for the deep (D) and superficial (S) zones of the following regions:
central medial and lateral femur (cMF, cLF), medial and lateral tibia (MT, LT). Changes in T2Me in
response to HDT-BR and countermeasures were evaluated using linear mixed-effects models.
Results: T2Me (in ms, mean±standard deviation (SD) for all time points are summarized in Table 1.
T2Me in the central medial femur superficial layer (cMFST2Me) changed over time (p=0.038), with a
decrease of 2.1% ((95% confidence interval of the difference (95%CI) CI: [-2.4%; -2.0%]) at R+6
compared to BDC-7 (p=0.014, Table 1). The cumulative effect of all campaigns (3*3 weeks of HDT-BR;
R+6 of C3 vs. BDC-7 of C1) within 12 months was a significant decrease in T2Me of the medial tibia
superficial layer (MTST2Me, -2.6% (95%CI: [-3.1%; -2.3%], p=0.037) and a significant increase in T2Me of
the central lateral femur deep layer (cLFDT2Me, +3.1% 95%CI: [2.8%; 3.5%], p=0.039; Figure 1). Neither
exercise nor nutrition countermeasures affected T2Me in any of the cartilage regions.
Conclusions: 21 days of bedrest immobilization decreased knee cartilage T2Me of the central medial
femur superficial layer (cMFST2Me) in healthy male individuals. The cumulative effect of three
campaigns of 21-days of bedrest immobilization within 12 months resulted in changes of T2 relaxation
times of medial tibia superficial layer and central lateral femur deep layer. Resistive vibration exercise
and whey protein supplementation did not appear to affect T2 relaxation times of femur and tibia.
These results are in agreement with previous bed rest studies showing pronounced effects of bed rest
without clear effects of different nutrition and / or exercise interventions on knee cartilage. Our data
suggest that even shorter periods of immobilization can result in systematic changes of articular
cartilage that are detectable by MRI T2 imaging techniques indicating that cartilage quality is affected
by immobilization. Although such effects are specific to cartilage layers and zones, the underlying
physiological processes necessitate further investigation.
OriginalspracheEnglisch
TitelRESPONSE OF KNEE CARTILAGE T2 RELAXATION TIMES TO 21-DAYS OF 6°HEAD-DOWN-TILT BED REST COMBINED WITH EXERCISE AND NUTRITION COUNTERMEASURES
Seitenumfang2
ErscheinungsortOsteoarthritis and Cartilage Journal
Erscheinungsdatum2023
Seiten318-319
DOIs
PublikationsstatusVeröffentlicht - 2023
VeranstaltungOARSI World Congress on Osteoarthritis Denver, Colorado - Sheraton Denver Downtown Hotel 1550 Court Pl. Denver, CO 80202 United States, Denver, USA/Vereinigte Staaten von Amerika
Dauer: 17.03.202320.03.2023
https://oarsi.org/node/907

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