Effects of 12-week combined exercise on RANKL/RANK/OPG signaling and bone-resorption cytokines in healthy college females

Review of osteokines in spinal cord injury: potential biomarkers during rehabilitation

After spinal cord injury (SCI), mechanical unloading, denervation, as well as negative changes in blood supply, inflammation state, and hormone levels produce significant negative effects on bone density, leading to a high prevalence of osteoporosis after SCI. It has been recently discovered that skeletal bone also has endocrine functions. Osteokines, secreted from bone tissue, could play multiple roles in regulating bone density, muscle mass, glucose metabolism, and functions of the central nervous system-changes in the osteokine levels after SCI have been detected. Therefore, bone density and osteokine levels should be stressed in clinical settings. Clinical treatment measures for bone loss after SCI include exercise training, physical agent therapy, acupuncture, and so on. According to previous studies, these treatments could affect the expression levels of osteokines. In conclusion, bone loss and changes in osteokines after SCI are worthy of great attention during the rehabilitation of SCI. Osteokines could become biomarkers during SCI rehabilitation, reflecting both bone density and systemic functions. This review summarized recent findings regarding bone loss after SCI, changes in osteokines, and the effect of rehabilitation therapies, with a particular emphasis on the local and systemic regulatory roles of osteokines, as well as their potential as biomarkers during SCI rehabilitation.

Influence of sex hormones status and type of training on regional bone mineral density in exercising females

The primary objective of this study was to examine the influence of hormonal ovarian profile and training characteristics on spine, pelvis, and total body bone mineral density (BMD) in a group of well-trained females. Forty-two eumenorrheic females, twenty-eight monophasic oral contraceptive (OC) users and thirteen postmenopausal females participated in this study. Body composition was measured by total body dual-energy X-ray absorptiometry (DXA) to determine BMD of the areas of interest. Endurance-trained premenopausal females showed lower spine BMD compared to resistance-trained premenopausal females (1.03 ± 0.1 vs. 1.09 ± 0.09 g/cm2; p = 0.025). Postmenopausal females reported lower BMD level in comparison to eumenorrheic females in pelvis (1.079 ± 0.082 vs 1.19 ± 0.115 g/cm2; p = 0.005), spine (0.969 ± 0.097 vs 1.069 ± 0.109 g/cm2; p = 0.012) and total (1.122 ± 0.08 vs 1.193 ± 0.077 g/cm2; p = 0.018) and OC users whose duration of OC use was less than 5 years (OC < 5) in pelvis (1.235 ± 0.068 g/cm2; p < 0.001) and spine (1.062 ± 0.069 g/cm2; p = 0.018). In addition, lower BMD values were found in OC users who had been using OC for more than 5 years (OC ≥ 5) than eumenorrheic females in pelvis (1.078 ± 0.086 g/cm2; p = 0.029) and spine (0.966 ± 0.08 g/cm2; p = 0.05). Likewise, OC ≥ 5 showed lower values than and OC < 5 in pelvis (p = 0.004) and spine (p = 0.047). We observed a lower spine BMD value in premenopausal endurance-trained females compared to premenopausal resistance-trained females. Moreover, this research observed that prolonged use of OCs may reduce bone mass acquisition in the spine and pelvis, even in well-trained females. Finally, postmenopausal showed lower BMD despite being exercising women.Trial registration: ClinicalTrials.gov identifier: NCT04458662.Highlights Ovarian hormonal profile should be considered when assessing BMD in female athletes.The duration of oral contraceptive use influences spine and pelvis regional BMD in exercising females.Postmenopausal women show lower BMD when compared to premenopausal females despite being exercising females.

The Role of Oxidative Stress in Multiple Exercise-Regulated Bone Homeostasis

Bone is a tissue that is active throughout the lifespan, and its physiological activities, such as growth, development, absorption, and formation, are always ongoing. All types of stimulation that occur in sports play an important role in regulating the physiological activities of bone. Here, we track the latest research progress locally and abroad, summarize the recent, relevant research results, and systematically summarize the effects of different types of exercise on bone mass, bone strength and bone metabolism. We found that different types of exercise have different effects on bone health due to their unique technical characteristics. Oxidative stress is an important mechanism mediating the exercise regulation of bone homeostasis. Excessive high-intensity exercise does not benefit bone health but induces a high level of oxidative stress in the body, which has a negative impact on bone tissue. Regular moderate exercise can improve the body's antioxidant defense ability, inhibit an excessive oxidative stress response, promote the positive balance of bone metabolism, delay age-related bone loss and deterioration of bone microstructures and have a prevention and treatment effect on osteoporosis caused by many factors. Based on the above findings, we provide evidence for the role of exercise in the prevention and treatment of bone diseases. This study provides a systematic basis for clinicians and professionals to reasonably formulate exercise prescriptions and provides exercise guidance for patients and the general public. This study also provides a reference for follow-up research.

Effect of Aerobic/Strength Training on RANKL Gene DNA Methylation Levels

BACKGROUND

The osteoclastogenesis RANKL gene plays a key role in bone remodeling. The hypomethylation of its promoter region may cause osteoporosis. The present study aimed to elucidate the influence of physical activity on DNA methylation changes of RANKL promoter cytosine-phosphate-guanine (CpG)-rich region in active and sedentary adults and to assess the effect of aerobic and strength training on RANKL DNA methylation changes among Tunisian-North African adults.

METHODS

A total of 104 participants including 52 adults (58% males and 42% females) and 52 adults (31% males and 69% females) were recruited for the observational and interventional part of the study, respectively. The intervention consisted of 12 weeks of aerobic training (30 min/session) followed by 10 minutes of strengthening exercises. All participants completed the International Physical Activity Questionnaire and provided blood samples for quantitative methylation-specific polymerase chain reaction (PCR) analysis.

RESULTS

The study revealed a significant difference (P = 6 × 10-10) in the methylation level of the RANKL promoter region between active and sedentary adults, with a 6.68-fold increase observed in the active group. After the intervention, both the trained (P = 41 × 10-5) and untrained (P = .002) groups displayed high methylation levels in the RANKL promoter region. In addition, the trained group exhibited significant improvements in heart rate (P = 2.2 × 10-16), blood pressure (P = 39 × 10-3), maximal oxygen uptake (P = 1.5 × 10-7), and fat mass (P = 7 × 10-4).

CONCLUSION

Exploring epigenetic modifications in the RANKL promoter region may contribute to a more comprehensive understanding of the complexity of osteoporosis. This suggests that aerobic/strength training could potentially improve the bone system, reducing its vulnerability to osteoporosis by increasing RANKL DNA methylation.

The Potential Mechanism of Exercise Combined with Natural Extracts to Prevent and Treat Postmenopausal Osteoporosis

Postmenopausal osteoporosis (PMOP) is a systemic chronic bone metabolic disease caused by the imbalance between bone formation and bone resorption mediated by estrogen deficiency. Both exercise and natural extracts are safe and effective means to prevent and control PMOP. The additive effect of exercise synergy extract against PMOP may be no less than that of traditional medicine. However, the mechanism of action of this method has not been clarified in detail. A large number of studies have shown that the pathogenesis of PMOP mainly involves the OPG-RANKL-RANK system, inflammation, and oxidative stress. Based on the abovementioned approaches, the present study reviews the anti-PMOP effects and mechanisms of exercise and natural extracts. Finally, it aims to explore the possibility of the target of the two combined anti-PMOP through this approach, thereby providing a new perspective for joint intervention research and providing a new direction for the treatment strategy of PMOP.

Circulating Levels of Bone Markers after Short-Term Intense Training with Increased Dairy Consumption in Adolescent Female Athletes

Thirteen female adolescent soccer players (14.3 ± 1.3 years) participated in a cross-over, double-blind trial examining the effects of Greek yogurt (GY) consumption on bone biomarkers during 5 days of intense soccer training. The study took place over two intervention weeks, which consisted of a pre-training assessment day, 5 training days, and a post-training assessment day. Participants completed the GY condition and a carbohydrate isocaloric placebo control pudding condition (CHO) in random order, 4 weeks apart. Morning, fasted, resting blood samples were collected pre- and post-training in each condition. Total osteocalcin (tOC), undercarboxylated osteocalcin (unOC), C-terminal telopeptide of type 1 collagen (CTX), osteoprotegerin (OPG), and receptor activator nuclear factor kappa-β ligand (RANKL) were measured in serum. The results showed no effects for time (pre- to post-training) or condition, and no interaction for tOC, CTX, OPG, RANKL, and the OPG/RANKL ratio. A time-by-condition interaction (p = 0.011) was observed in unOC, reflecting a post-training decrease in the GY, but not the CHO condition (-26% vs. -3%, respectively). However, relative unOC (% of tOC) decreased post-training (-16%), with no differences between conditions. These findings suggest that short-term high-impact intense training had no direct catabolic impact on bone metabolism, with GY adding no benefit beyond that of the isocaloric CHO control pudding.

RANKL/RANK/OPG Pathway: A Mechanism Involved in Exercise-Induced Bone Remodeling

Bones as an alive organ consist of about 70% mineral and 30% organic component. About 200 million people are suffering from osteopenia and osteoporosis around the world. There are multiple ways of protecting bone from endogenous and exogenous risk factors. Planned physical activity is another useful way for protecting bone health. It has been investigated that arranged exercise would effectively regulate bone metabolism. Until now, a number of systems have discovered how exercise could help bone health. Previous studies reported different mechanisms of the effect of exercise on bone health by modulation of bone remodeling. However, the regulation of RANKL/RANK/OPG pathway in exercise and physical performance as one of the most important remodeling systems is not considered comprehensive in previous evidence. Therefore, the aim of this review is to clarify exercise influence on bone modeling and remodeling, with a concentration on its role in regulating RANKL/RANK/OPG pathway.

Obesity-Induced Changes in Bone Marrow Homeostasis

Obesity is characterized by low-grade inflammation, which is accompanied by increased accumulation of immune cells in peripheral tissues including adipose tissue (AT), skeletal muscle, liver and pancreas, thereby impairing their primary metabolic functions in the regulation of glucose homeostasis. Obesity has also shown to have a detrimental effect on bone homeostasis by altering bone marrow and hematopoietic stem cell differentiation and thus impairing bone integrity and immune cell properties. The origin of immune cells arises in the bone marrow, which has been shown to be affected with the obesogenic condition via increased cellularity and shifting differentiation and function of hematopoietic and bone marrow mesenchymal stem cells in favor of myeloid progenitors and increased bone marrow adiposity. These obesity-induced changes in the bone marrow microenvironment lead to dramatic bone marrow remodeling and compromising immune cell functions, which in turn affect systemic inflammatory conditions and regulation of whole-body metabolism. However, there is limited information on the inflammatory secretory factors creating the bone marrow microenvironment and how these factors changed during metabolic complications. This review summarizes recent findings on inflammatory and cellular changes in the bone marrow in relation to obesity and further discuss whether dietary intervention or physical activity may have beneficial effects on the bone marrow microenvironment and whole-body metabolism.