Musculoskeletal Effects of Altered GH Action

Comprehensive assessment of tris(2-ethylhexyl) trimellitate acute toxicity and ecological risks: Species-specific sensitivity and environmental monitoring

Tris(2-ethylhexyl) trimellitate (TOTM), a non-phthalate plasticizer, has gained popularity as a safer alternative to phthalates; however, its ecotoxicological impact and environmental behavior remain unclear. In this study, we investigated the species-specific sensitivity of Oryzias latipes (Japanese medaka) and Danio rerio (zebrafish) to TOTM exposure, and determined the residual concentrations in aquatic environments and ecological risk. Embryonic and larval toxicity tests revealed significant species differences: zebrafish showed higher sensitivity, with a lowest observed effect concentration (LOEC) of 43.7 μg/L, exhibiting increased mortality, swim bladder inflation failure, and growth inhibition. In contrast, the Japanese medaka showed no significant adverse effects under similar exposure conditions. TOTM residues were detected in a single sample (348.2 ng/L) after environmental monitoring of the Sumiyoshi River over 3 months, highlighting potential environmental persistence despite limited detection. Risk assessment using the ratio of the measured environmental concentration (MEC) to the predicted no effect concentration (PNEC) revealed a value > 13, indicating a significant ecological risk posed by the TOTM. These findings underscore the importance of evaluating species-specific responses, conducting comprehensive environmental monitoring, and addressing ecological risks associated with TOTM contamination in aquatic environments.

Sarcopenic obesity and physical function in acromegaly: impact of disease control and evaluation using dual X-ray absorptiometry and multifrequency bioelectrical impedance analysis

PURPOSE

To assess sarcopenia, sarcopenic obesity, physical performance in patients with acromegaly and compare the diagnostic performance of dual-energy X-ray absorptiometry (DXA) and multifrequency bioelectrical impedance analysis (BIA).

METHODS

This cross-sectional study included 27 patients with acromegaly and 27 age-, sex-, and BMI-matched patients without acromegaly. Body composition was assessed using BIA and DXA. Lean mass indices included fat-free mass index (FFMI) and skeletal muscle index (SMI) via BIA, and the Baumgartner (BMG) and Foundation for the National Institutes of Health indices via DXA. Obesity parameters included fat mass index (FMI) and body fat percentage via BIA. Physical performance was evaluated using handgrip strength (HGS), Timed Up and Go (TUG), 4-m gait speed (4MGS), and the Short Physical Performance Battery (SPPB) tests. The strength, assistance in walking, rising from a chair, climbing stair and falls (SARC-F) questionnaire was also performed.

RESULTS

Strong correlations were observed between BIA and DXA body composition measures (r = 0.83, p < 0.01 for %BIA fat mass vs. %DXA fat mass; r = 0.80, p < 0.01 for SMI vs. BMG and r = 0.80, p < 0.01 for FFMI vs. BMG). Patients with acromegaly had significantly higher FFMI than patients without the disease (p = 0.03), but no difference in sarcopenic obesity prevalence (p = 0.50). Patients with acromegaly performed worse in the TUG and 4MGS tests, even after adjustment for confounders (p < 0.01 for both). No significant associations were found between SARC-F scores and lean mass or physical performance.

CONCLUSION

Patients with acromegaly showed impaired physical performance despite higher FFMI, with no differences in sarcopenic obesity. The SARC-F questionnaire showed limited diagnostic value in this population.

The bone-muscle unit: from mechanical coupling to soluble factors-mediated signaling

Skeletal muscles (SKM) and bones form a morpho-functional unit, interconnected throughout life primarily through biomechanical coupling. This relationship serves as a key reciprocal stimulus, but they also interact via various hormones, such as sex steroids, growth hormone-insulin-like growth factor 1 (GH-IGF1) axis hormones, and adipokines like leptin and adiponectin. Additionally, myokines (released by muscles) and osteokines (released by bones) facilitate dense crosstalk, influencing each other's activity. Key myokines include interleukin (IL)-6, IL-7, IL-15, and myostatin, while osteocalcin (OC) and sclerostin are crucial bone-derived mediators affecting SKM cells. Moreover, miRNAs act as endocrine-like regulators, contributing to a complex network. This review covers the current understanding of bone-muscle crosstalk, which is essential for grasping the musculoskeletal apparatus's role in disease pathogenesis and may inform therapeutic development.

Cervical osteophyte complex causing compressive myelopathy leading to a diagnosis of acromegaly

A young male patient presented with acute onset spastic quadriparesis. Clinically, he exhibited features of acromegaly alongside spastic quadriparesis. Neuroimaging revealed an osteophyte complex causing cord compression and canal stenosis. Biochemical and radiological assessments confirmed a growth hormone-secreting pituitary macroadenoma. He underwent anterior cervical discectomy with vertebral fusion of the cervical cord to relieve his neurological symptoms. His acromegaly was subsequently managed with surgery, followed by radiotherapy and medical therapy. While acromegaly may rarely present as a metabolic emergency, neurological emergencies are exceptionally rare. This is the first case report of acromegaly, which was recognised on presentation with an osteophyte complex causing quadriparesis.

Update on regulation of GHRH and its actions on GH secretion in health and disease

This review focuses on our current understanding of how growth hormone releasing hormone (GHRH): 1) stimulates GH release and synthesis from pituitary growth hormone (GH)-producing cells (somatotropes), 2) drives somatotrope proliferation, 3) is negatively regulated by somatostatin (SST), GH and IGF1, 4) is altered throughout lifespan and in response to metabolic challenges, and 5) analogues can be used clinically to treat conditions of GH excess or deficiency. Although a large body of early work provides an underpinning for our current understanding of GHRH, this review specifically highlights more recent work that was made possible by state-of-the-art analytical tools, receptor-specific agonists and antagonists, high-resolution in vivo and ex vivo imaging and the development of tissue (cell) -specific ablation mouse models, to paint a more detailed picture of the regulation and actions of GHRH.

Effectiveness of Early Versus Late Time-Restricted Eating Combined with Physical Activity in Overweight or Obese Women

AIMS

To evaluate the effectiveness of a dual approach involving time-restricted eating (TRE) at different times of the day combined with physical activity (PA) on functional capacity and metabolic health in overweight or obese women.

METHODS

Random allocation of sixty-one participants into four groups: early time-restricted eating plus physical activity (ETRE-PA, n = 15, 31.8 ± 10.76 years, 89.68 ± 13.40 kg, 33.5 ± 5.53 kg/m2), late time-restricted eating with physical activity (LTRE-PA, n = 15, 30.60 ± 7.94 years, 94.45 ± 15.36 kg, 34.37 ± 7.09 kg/m2), late time-restricted eating only (LTRE, n = 15, 27.93 ± 9.79 years, 88.32 ± 10.36 kg, 32.71 ± 5.15 kg/m2) and a control group (CG, n = 15, 36.25 ± 11.52 years, 89.01 ± 11.68 kg, 33.66 ± 6.18 kg/m2). The intervention lasted for 12 weeks in all groups. Both the ETRE-PA and LTRE-PA groups engaged in a rigorous combined aerobic and resistance-training program.

RESULTS

Significant reductions in body weight and body mass index were observed in the ETRE-PA and LTRE-PA groups compared to the CG and LTRE groups post-intervention (p < 0.0005). Only the ETRE-PA group exhibited a significant decrease in fat mass (p = 0.02), low-density lipoprotein cholesterol (p = 0.01), and aspartate aminotransferase (p = 0.002). Significant reductions in alanine aminotransferase levels were observed in the ETRE-PA (p = 0.004) and LTRE-PA (p = 0.02) groups. These two latter groups achieved higher performances in the 6-min walking test, bench press, 30-s squat, crunch test, vertical jump (p < 0.0005 for both), and leg extension (p < 0.02 for both) when compared to the LTRE and CG groups.

CONCLUSION

The integration of TRE with PA leads to greater improvements in body composition, lipid profile, and physical performance, with no significant differences between the ETRE-PA and LTRE-PA approaches. This combined strategy offers a promising solution for overweight and obese women.

The Causal Effect of Adult Height on Late-Life Handgrip Strength: The Singapore Chinese Health Study

BACKGROUND

Adult height has been associated with handgrip strength, which is a surrogate marker of physical frailty. However, it is uncertain if this association is causative or due to confounding bias.

METHODS

We evaluated pairwise associations among handgrip strength, adult height, and genetically determined height (using a polygenic score [PGS] for height in a mediation framework and a 2-sample Mendelian randomization approach) by means of a multivariable regression model using a prospective cohort of Chinese living in Singapore. We additionally evaluated pathway enrichments of height-related genes in relation to increased handgrip strength to discover common biological mechanisms underlying associations of genetically determined height with handgrip strength.

RESULTS

Height PGS exhibited a positive association with handgrip strength at late life after adjusting for midlife body weight and other baseline exposures (cigarette smoking, education, and physical activity status, p = 1.2 × 10-9). Approximately 66.4% of the total effect of height PGS on handgrip strength was mediated through adult height (βindirect-effect = 0.034, pindirect-effect = 1.4 × 10-40). Two-sample Mendelian randomization evaluations showed a consistent causal relationship between increased height and increased handgrip strength in late life (p between 6.6 × 10-4 and 3.9 × 10-18), with insignificant horizontal pleiotropic effects (pMR-Egger intercept = 0.853). Pathway analyses of genes related to both increased adult height and handgrip strength revealed enrichment in ossification and adipogenesis pathways (padj between .034 and 6.8 × 10-4).

CONCLUSIONS

The study highlights a potentially causal effect between increased adult height and increased handgrip strength in late life, which may be explained by related biological processes underlying the preservation of muscle mass and strength in aging.

Deciphering Osteosarcopenia through the hallmarks of aging

Osteosarcopenia is a major driver of functional loss and a risk factor for falls, fractures, disability and mortality in older adults, urgently requiring the development of effective interventions to address it. The hallmarks of aging provide a theoretical and practical framework that allows for the structured organization of current knowledge and the planning of new development lines. This article comprehensively reviews the currently available literature on the role of the hallmarks of aging in the development of osteosarcopenia, thereby offering a panoramic view of the state of the art and knowledge gaps in this field.

Transition Period and Young Adulthood in Patients with Childhood Onset Growth Hormone Deficiency (COGHD): Impact of Growth Hormone Replacement on Bone Mass and Body Composition

The aim of this review article is to highlight the consequences of COGHD after the end of linear growth on bone mass and body composition and the opposing beneficial effects of continuing GH replacement in the transition period and young adults. The role of growth hormone in the period of late adolescence and young adulthood is well established, mainly in achieving peak bone mass and a favorable body composition, characterized by muscle mass increase and fat mass reduction. Patients with childhood onset growth hormone deficiency (COGHD), after reaching the adult height, have a reduced bone mineral density and muscle mass with increased fat mass compared to healthy controls. Inadequate body composition is a predictor for cardiovascular risk, while low bone mass in early youth hallmarks the risk of osteoporosis and bone fractures in later life. Cessation of growth hormone replacement (GHr) after completion of growth will lead to delayed peak bone mass and unbalanced body composition with increased abdominal fat deposits. According to numerous clinical studies monitoring the effects of GH treatment on the physical and psychological status of patients with persistent GHD after completion of growth, we suggest continuing this treatment between 16 and 25 years of age. It is advised that GHr in the transition period be administered in intermediate doses between those for the pediatric population and those for the adult population. Usual daily GHr doses are between 0.3 and 0.5 mg but need to be individually optimized, with the aim of maintaining IGF-I in the age-specific normal range.

Body Composition, Sarcopenia, and Serum Myokines in Acromegaly: A Narrative Review

Patients with active acromegaly have a higher percentage of lean body mass, a lower percentage of fat body mass, and an increase in their extracellular water compartment compared to healthy individuals. However, muscle function appears to be compromised in patients with acromegaly, with some experiencing worsened physical performance and sarcopenia. Myokine alterations, insulin resistance, dysregulation of protein metabolism, muscle oxidative stress, neuromuscular junction impairment, and increased ectopic intramuscular fat deposits may play roles in muscle dysfunction in patients with acromegaly.

Research Progress on the Regulating Factors of Muscle Fiber Heterogeneity in Livestock: A Review

The type of muscle fiber plays a crucial role in the growth, development, and dynamic plasticity of animals' skeletal muscle. Additionally, it is a primary determinant of the quality of both fresh and processed meat. Therefore, understanding the regulatory factors that contribute to muscle fibers' heterogeneity is of paramount importance. Recent advances in sequencing and omics technologies have enabled comprehensive cross-verification of research on the factors affecting the types of muscle fiber across multiple levels, including the genome, transcriptome, proteome, and metabolome. These advancements have facilitated deeper exploration into the related biological questions. This review focused on the impact of individual characteristics, feeding patterns, and genetic regulation on the proportion and interconversion of different muscle fibers. The findings indicated that individual characteristics and feeding patterns significantly influence the type of muscle fiber, which can effectively enhance the type and distribution of muscle fibers in livestock. Furthermore, non-coding RNA, genes and signaling pathways between complicated regulatory mechanisms and interactions have a certain degree of impact on muscle fibers' heterogeneity. This, in turn, changes muscle fiber profile in living animals through genetic selection or environmental factors, and has the potential to modulate the quality of fresh meat. Collectively, we briefly reviewed the structure of skeletal muscle tissue and then attempted to review the inevitable connection between the quality of fresh meat and the type of muscle fiber, with particular attention to potential events involved in regulating muscle fibers' heterogeneity.

Effects of glycyrrhiza polysaccharides on growth performance, meat quality, serum parameters and growth/meat quality-related gene expression in broilers

With growing restrictions on the use of antibiotics in animal feed, plant extracts are increasingly favored as natural feed additive sources. Glycyrrhiza polysaccharide (GP), known for its multifaceted biological benefits including growth promotion, immune enhancement, and antioxidative properties, has been the focus of recent studies. Yet, the effects and mechanisms of GP on broiler growth and meat quality remain to be fully elucidated. This study aimed to investigate the effects of GP on growth, serum biochemistry, meat quality, and gene expression in broilers. The broilers were divided into five groups, each consisting of five replicates with six birds. These groups were supplemented with 0, 500, 1,000, 1,500, and 2,000 mg/kg of GP in their basal diets, respectively, for a period of 42 days. The results indicated that from day 22 to day 42, and throughout the entire experimental period from day 1 to day 42, the groups receiving 1,000 and 1,500 mg/kg of GP showed a significant reduction in the feed-to-gain ratio (F:G) compared to the control group. On day 42, an increase in serum growth hormone (GH) levels was shown in groups supplemented with 1,000 mg/kg GP or higher, along with a significant linear increase in insulin-like growth factor-1 (IGF-1) concentration. Additionally, significant upregulation of GH and IGF-1 mRNA expression levels was noted in the 1,000 and 1,500 mg/kg GP groups. Furthermore, GP significantly elevated serum concentrations of alkaline phosphatase (AKP) and globulin (GLB) while reducing blood urea nitrogen (BUN) levels. In terms of meat quality, the 1,500 and 2,000 mg/kg GP groups significantly increased fiber density in pectoral muscles and reduced thiobarbituric acid (TBA) content. GP also significantly decreased cooking loss rate in both pectoral and leg muscles and the drip loss rate in leg muscles. It increased levels of linoleic acid and oleic acid, while decreasing concentrations of stearic acid, myristic acid, and docosahexaenoic acid. Finally, the study demonstrated that the 1,500 mg/kg GP group significantly enhanced the expression of myogenin (MyoG) and myogenic differentiation (MyoD) mRNA in leg muscles. Overall, the study determined that the optimal dosage of GP in broiler feed is 1,500 mg/kg.

Molecular characterization of physis tissue and hormonal profiles of female rats neonatally exposed to low-dose bisphenol A

Physis is a complex cartilaginous structure that is critical for longitudinal bone growth. As one of the endocrine-disrupting chemicals, bisphenol A (BPA) can interfere with the physis by deranging the complex networks of nutritional, cellular, paracrine, and endocrine factors, and this affects longitudinal bone growth, leading to different growth outcomes. However, the exact mechanisms underlying these phenomena remain unclear. Therefore, understanding the molecular pathways involved in the physis after neonatal exposure to low-dose BPA may permit the identification of research targets for therapeutics, which may aid in modulating the process of growth plate closure. In the present study, female Sprague-Dawley rats were exposed to 0.05 mg·kg^-1·day^-1 of BPA and corn oil vehicle from postnatal day 1 (PND1) to 15 via subcutaneous injection. Next-generation RNA sequencing was performed for the mRNA isolated from the physis. The levels of osteocalcin (OC), growth hormone (GH), and insulin-like growth factor 1 (IGF-1) were measured on PND30 (BPA0.05mg vs. Vehicle; n = 5 for each group). We observed statistically significant enrichment of gene sets in the BPA0.05mg tissues compared with the Vehicle tissues. Further analysis of the differentially expressed genes (DEGs) identified BPA0.05mg-specific networks of secreted proteins (LEP, NPY, AGT, ACE2, C4B, and C4BPA) as well as those of local matrix and protease proteins (FBN2, LAMC2, ADAMTS16, and ADAMTS19). Furthermore, the levels of OC and GH were affected by BPA exposure. Our results revealed the specific molecular characteristics of physis contaminated with BPA and may provide new clues for physis maturation and supervision of industrial products and occupational exposure.

Effects of 18 Months of Growth Hormone Replacement Therapy on Bone Mineral Density in Patients with Adult Growth Hormone Deficiency: A Retrospective Study

OBJECTIVE

The effect of physiological dose growth hormone (GH) replacement therapy on bone mineral density (BMD) in adults with growth hormone deficiency (GHD) is not well defined. We aimed to investigate the effects of 18 months of treatment with recombinant human growth hormone (rhGH) at physiological doses on BMD, body composition (BC), and quality of life (QoL).

METHODS

Sixty-eight patients diagnosed with adult growth hormone deficiency (AGHD) in our hospital were included in this retrospective study. All patients received individualized rhGH replacement to maintain normal serum insulin-like growth factor-1 (IGF-1) levels. BMD and BC measurements were performed by dual energy X-ray absorptiometry (DXA). Excluding those with incomplete follow-up data, we analyzed BMD in 68 patients, as well as BC and QoL in 36 of them.

RESULTS

Compared with the baseline, lumbar spine BMD decreased by 0.008 g/cm² (P=0.006) and increased by 0.011 g/cm² (P=0.045) at month 18, and total hip BMD decreased by 0.005 g/cm² (P=0.008) and did not change significantly from the baseline at month 18. The changes in BMD did not differ by sex, and the increase in BMD was more pronounced in patients with low Z-scores at the baseline (lumbar spine: P=0.005 and total hip: P=0.018). The percentage change from the baseline in BMD was greater for the lumbar spine than for the total hip (P=0.003). Lean body mass (LBM) increased significantly (P=0.012), total body fat ratio (TBF%) decreased significantly (P=0.011), visceral adipose tissue (VAT) decreased significantly (P=0.016), and QoL improved significantly (P < 0.001).

CONCLUSIONS

Within 18 months of treatment, bone resorption manifested first, BMD decreased to a nadir at month 6, and then it increased. The increase in BMD was greater in the lumbar spine than in the hip, and the increase was more pronounced in patients with low BMD. Eighteen months of rhGH replacement therapy significantly improved lumbar spine BMD and improved BC and QoL.