Joint Cartilage in Long-Duration Spaceflight

Treatment with a superoxide dismutase mimetic for joint preservation during 35 and 75 days in orbit aboard the international space station, and after 120 days recovery on Earth

Reduced weight-bearing during spaceflight has been associated with musculoskeletal degradation that risks astronaut health and performance in transit and upon reaching deep space destinations. Previous rodent experiments aboard the international space station (ISS) have identified that the spaceflight-induced molecular arthritic phenotype was characterized with an increase in oxidative stress. This study evaluated if treatment with a superoxide dismutase (SOD) mimetic on orbit could prevent spaceflight-induced damage to the knee and hip articular cartilage, and the menisci in rodents. Cartilage and meniscal degradation in mice were measured via microCT, histology, and transcriptomics after: (1) ∼ 35 days on the ISS, (2) ∼ 35 days on the ISS followed by 120 days weight-bearing readaptation on Earth or (3) ∼ 75 days on the ISS. The study had a limited sample size, so both significant effects and generalized patterns are reported. After 35 days aboard the ISS, cartilage volume at the tibial-femoral cartilage-cartilage contact point decreased, meniscal volume decreased concurrent with an increase in pro-osteoarthritic signaling in the joint soft tissue. Similarly, a decrease in cortical and trabecular bone volume of the tibia was observed. Treatment with the SOD mimetic preserved the trabecular bone, articular cartilage and the menisci after 35 days aboard the ISS, but had limited efficacy retaining that recovery after 120 days of weight bearing, and after 75 days on orbit. Antioxidants including BuOE may serve as a potential countermeasure option to protect musculoskeletal health during spaceflight missions, and continued use may be necessary upon reaching a destination.

Articular cartilage loss is an unmitigated risk of human spaceflight

Microgravity and space radiation are hazards of spaceflight that have deleterious effects on articular cartilage. Since it is not widely monitored or protected through dedicated countermeasures, articular cartilage loss is an unmitigated risk of human spaceflight. Spaceflight-induced cartilage loss will affect an astronaut's performance during a mission and long-term health after a mission. Addressing concerns for cartilage health will be critical to the continued safe and successful exploration of space.

Growth and mineralization of fetal mouse long bones under microgravity and daily 1 g gravity exposure

In a previous Space Shuttle/Spacelab experiment (STS-42), we observed direct responses of isolated fetal mouse long bones to near weightlessness. This paper aimed to verify those results and study the effects of daily 1×g exposure during microgravity on the growth and mineralization of these bones. Two experiments were conducted: one on an American Space Shuttle mission (IML-2 on STS-65) and another on a Russian Bio-Cosmos flight (Bion-10 on Cosmos-2229). Despite differences in hardware, both used 17-day-old fetal mouse metatarsals cultured for 4 days. Results showed reduced proteoglycan content under microgravity compared to 1×g conditions, with no main differences in other cellular structures. While the overall metatarsal length was unaffected, the length increase of the mineralized diaphysis was significantly reduced under microgravity. Daily 1×g exposure for at least 6 h abolished the microgravity-induced reduction in cartilage mineralization, indicating the need for long-duration exposure to 1×g as an in-flight countermeasure using artificial gravity.

Organs in orbit: how tissue chip technology benefits from microgravity, a perspective

Tissue chips have become one of the most potent research tools in the biomedical field. In contrast to conventional research methods, such as 2D cell culture and animal models, tissue chips more directly represent human physiological systems. This allows researchers to study therapeutic outcomes to a high degree of similarity to actual human subjects. Additionally, as rocket technology has advanced and become more accessible, researchers are using the unique properties offered by microgravity to meet specific challenges of modeling tissues on Earth; these include large organoids with sophisticated structures and models to better study aging and disease. This perspective explores the manufacturing and research applications of microgravity tissue chip technology, specifically investigating the musculoskeletal, cardiovascular, and nervous systems.

Long-term space missions' effects on the human organism: what we do know and what requires further research

Space has always fascinated people. Many years have passed since the first spaceflight, and in addition to the enormous technological progress, the level of understanding of human physiology in space is also increasing. The presented paper aims to summarize the recent research findings on the influence of the space environment (microgravity, pressure differences, cosmic radiation, etc.) on the human body systems during short-term and long-term space missions. The review also presents the biggest challenges and problems that must be solved in order to extend safely the time of human stay in space. In the era of increasing engineering capabilities, plans to colonize other planets, and the growing interest in commercial space flights, the most topical issues of modern medicine seems to be understanding the effects of long-term stay in space, and finding solutions to minimize the harmful effects of the space environment on the human body.