Journal of Endocrinology最新文献

Next-generation sequencing (NGS) is increasingly used for diagnosing monogenic forms of diabetes, including Maturity-Onset Diabetes of the Young (MODY). We aimed to evaluate the utility of NGS in patients with clinical suspicion of MODY, analyzing genotype-phenotype correlations. A total of 150 unrelated patients from the Region of Murcia (Spain) with suspected MODY were included. Whole-exome sequencing was performed and validated with Sanger and multiplex ligation-dependent probe amplification (MLPA). Variants were classified according to the American College of Medical Genetics and Genomics (ACMG) criteria. Relevant clinical data were collected per the American Diabetes Association (ADA) and European Association for the Study of Diabetes (EASD) criteria and analyzed using SPSS v.27.0.2.0. The diagnostic yield was 16.67% (25/150). Pathogenic or likely pathogenic variants were mainly identified in GCK (38.89%) and HNF1A (33.33%). Significant differences were found between patients with and without genetic diagnosis in family history, age of onset, and body mass index (BMI) (p<0.05). Variants of uncertain significance (VUS) were identified in 22 families (14.66%). One VUS was reclassified as likely pathogenic, and three were prioritized for further evaluation. NGS is a valuable tool for the genetic diagnosis of MODY. Integration of clinical data and systematic re-evaluation and prioritization of VUS can enhance diagnostic accuracy and inform clinical decision-making.

Sirtuin 1 (Sirt1) plays a pivotal role in maintaining energy homeostasis, however the crosstalk of Sirt1 in bone remodeling and energy expenditure has not been well understood. In this study, tamoxifen (TAM)-induced osteoblast-specific Sirt1 conditional knockout (cKO) mice were generated by crossing Col1a1-CreERT2 mice with Sirt1 floxed mice, and these mice exhibited a lower-bone-mass phenotype associated with declined bone formation and accelerated bone resorption. Despite no significant change in glucose tolerance, Sirt1 cKO mice displayed modest insulin resistance as determined by impaired insulin tolerance tests and reduced hepatic insulin sensitivity, and lipid disturbance characterized by adipocyte expansion/hypertrophy, enhanced lipid synthesis and a potential defect in fatty acid oxidation (FAO) in inguinal white adipose tissue (iWAT). These metabolic disorders might be associated with decreased serum osteocalcin (OC) and its undercarboxylated form (ucOC), and impaired FAO and WNT/β-catenin pathway in osteoblasts. Further analysis showed that silencing Sirt1 in osteoblasts contributed to downregulation of enzymatic mediators of FAO and reduced cellular levels of ATP and FFA, which may be associated with the impaired WNT/β-catenin pathway in vivo and in vitro. Furthermore, treatment with the β-catenin agonist rescued the impairment of osteoblastic differentiation and FAO caused by Sirt1 knockout, which can be effectively blunted by etomoxir, a clinically approved FAO inhibitor. In conclusion, these data indicate that manipulation of osteoblast Sirt1 involves in fatty acid utilization and systemic glucolipid metabolism through β-catenin signaling.

Triac (3,3',5-triiodothyroacetic acid), is a thyroid hormone metabolite with thyromimetic properties. We investigated the effect of Triac on skeletal formation in larval zebrafish. Compared to other iodothyronines (T4, T3, 3,5-T2), Triac at nanomolar concentrations stimulated larval zebrafish osteoblast activity in vivo, measured in an sp7:luciferase transgenic line and by the expression of osteoblast-specific genes. The mineralisation of bone elements and whole-body calcium content were enhanced, and the expression of osteoblast- and bone matrix marker genes was stimulated. Triac increased the density of integumental ionocytes in the skin epithelium and expression of genes involved in calcium uptake increased significantly. No direct effect of Triac on osteoblasts of isolated zebrafish scales was found. The expression of stc1l, encoding the hypocalcaemic hormone stanniocalcin, was suppressed. We propose that Triac affects bone mineralisation by regulating both the uptake of calcium from the ambient water, and the exchange of calcium between its major body compartments: bone, blood, and soft tissue. We discuss possible direct and indirect pathways via which Triac affects bone mineralisation. Triac is present in effluents from sewage treatment plants, and has biological effects in sub-nanomolar concentrations. We postulate that Triac is an environmental endocrine disruptor.

Clinical use of glucocorticoids in large quantities over a long period of time causes glucocorticoid-induced osteoporosis (GIOP). lncRNA OIP5-AS1 has elevated levels in delayed fracture healing, so the present study explored the role of OIP5-AS1 in a model of GIOP. The GIOP model was induced in mice by different doses of dexamethasone. The levels of OIP5-AS1, miR-335-5p, LC3-II, P62 mRNA, and four markers of osteogenic differentiation were assessed by RT-qPCR in the serum of GIOP mice and MC3T3-E1 cells. Cell proliferation was assessed by the CCK-8 kit. Lactic acid (LA) was assayed by a LA kit. The binding sites of OIP5-AS1 and miR-335-5p were predicted by the ENCORI database. DLR assay verified the binding relationship between OIP5-AS1 and miR-335-5p. GIOP mice had elevated levels of OIP5-AS1 expression, elevated lactate levels, increased oxidative stress, active autophagy, and reduced levels of osteogenic differentiation. After knocking down OIP5-AS1 in cellular models, miR-335-5p levels were elevated, lactate levels were decreased, oxidative stress levels were decreased, autophagy was inhibited, and osteogenic differentiation was increased. However, after transfection of miR-335-5p inhibitor, the cells had elevated lactate levels, decreased proliferative capacity, increased oxidative levels, active autophagic behavior, and decreased osteogenic differentiation. OIP5-AS1 levels were elevated in the GIOP model. Knockdown of OIP5-AS1 resulted in elevated miR-335-5p levels, enhanced proliferation and differentiation of osteoblasts, and suppression of autophagy and oxidative stress. Therefore, OIP5-AS1 may alleviate the development of GIOP through miR-335-5p.

The relationship between alcohol consumption-particularly at low-to-moderate levels-and liver steatosis or fibrosis remains controversial, and the potential pathways involved are incompletely understood. Given that iron homeostasis is frequently disturbed in individuals who consume alcohol and may contribute to liver injury, we aimed to investigate whether alterations in iron metabolism link alcohol intake to hepatic injury. We analyzed data from the National Health and Nutrition Examination Survey (NHANES) and UK Biobank to examine associations between alcohol consumption and liver steatosis/fibrosis. Associations were assessed using multivariate logistic, Cox proportional hazards, restricted cubic spline (RCS), and Mendelian Randomization (MR) analysis, where appropriate. Mediation analysis was conducted to evaluate the role of iron-related biomarkers. We observed a J-shaped association between daily pure alcohol intake and liver fat (proton density fat fraction, PDFF), where low intake inversely and moderate-to-heavy intake positively associated. Higher alcohol consumption increased the risks of incident steatosis (HR=1.16, 95%CI: 1.13-1.19) and fibrosis (HR=1.47, 95%CI: 1.42-1.52). Iron homeostasis biomarkers partially mediated these associations, with liver iron showing the strongest mediation effect (19.44%). MR analysis further supported a causal link between genetically predicted alcohol intake and elevated liver iron and PDFF. These findings indicate that alcohol consumption is associated with higher liver fat and a detrimental impact on fibrosis risk, in part through disruption of iron homeostasis. Monitoring iron metabolism in individuals with alcohol exposure may therefore offer clinically relevant insights for identifying individuals at higher risk and informing strategies to prevent alcohol-related liver disease progression.

Obesity, officially recognised as a global epidemic by the World Health Organization, will soon overtake smoking as the largest preventable risk factor for cancer. By 2035, more than half the world's population is expected to be overweight or obese with a significant increase in obesity-related health expenditures. However, despite the increase in prevalence and the overall lower life expectancy associated with obesity, mechanisms underpinning obesity-driven diseases are not well understood. Adipocytes pose many challenges for in vitro culture due to their poor cell-to-surface attachment and low viability. Their large size and high lipid content can also present methodological challenges for downstream experiments. Several mouse and human-derived primary pre-adipocyte cell lines have been established over the years. However, they show limited renewal capacity and they cannot be cultured long term in vitro. Commercial cell lines available, which can be cultured long term, fail to represent organ-specific adipocyte heterogeneity. Adipose tissue from different organs and fat depots can show significant heterogeneity in terms of metabolism and overall secretome and extracellular matrix production. The prostate, for example, is surrounded by peri-prostatic adipose tissue (PPAT), the volume of which is associated with an increased risk of lethal prostate cancer and a reduced therapy response. Here, we outline a protocol for ex vivo culture of fresh PPAT and non-prostatic adipose tissue (NPAT), which reflects donor- and depot-specific characteristics. Ex vivo culture of PPAT/NPAT explants maintains cell-cell interactions and preserves local tissue architecture within adipose tissue. We have also described establishment of immortalised, patient PPAT-derived pre-adipocytes and patient-matched NPAT pre-adipocytes that can be in vitro differentiated into mature adipocytes. The protocols outlined here could be readily adapted to other organ-specific fat depots, such as mammary/bone marrow adipose tissue, and to tissues of non-human origin.

Polycystic ovary syndrome (PCOS) is characterized by reproductive and metabolic dysfunction that may also impact bone metabolism and its structural integrity. This study aims to assess the progressive impact of PCOS on bone health over time. It focuses on how the duration of the condition influences hormonal profiles, bone metabolism, and bone's microstructural and mechanical properties in the PCOS-induced mice model. Female BALB/c mice were separated into three groups, each further subdivided into PCOS-induced and age-matched control groups. PCOS was induced by letrozole (6 mg/kg b.w.) administered continuously for 21 days; among them, group II underwent a one-month observation period, while group III was observed for two months. Bone quality markers were assessed through hormonal profiling, serum bone turnover markers, micro-CT, three-point bending test, nanoindentation, and FTIR. Hormonal profiling revealed persistent hyperandrogenism, elevated luteinizing hormone/follicle-stimulating hormone ratio, reduced estrogen levels, and insulin resistance collectively affected bone health. Micro-CT analysis showed a decline in trabecular quality in the femur and tibia of the PCOS group. Three-point bending test pointed toward increased susceptibility to micro-damage and fracture. Nanoindentation indices, elasticity, and hardness were also decreased. FTIR analysis indicates alterations in bone material properties. These indices showed a slight improvement in the third month but deviated significantly from control. Our results suggest that PCOS has an adverse impact on bone's structural, mechanical, and compositional properties, and the negative impact of PCOS on skeletal integrity is not fully reversible in the short term. Overall, these findings highlight the importance of evaluating and monitoring bone health in PCOS individuals.

Diabetes is an increasingly prevalent global disease and is often accompanied by sarcopenia, particularly in older adults. While insulin resistance is a well-known contributor to muscle loss in diabetes, the role of glucose signaling in diabetic skeletal muscle atrophy, particularly under insulin-deficient conditions, remains poorly understood. This study aimed to elucidate the pathophysiological role of the carbohydrate-responsive element-binding protein (ChREBP), a glucose-sensing transcription factor encoded by the Chrebp gene in mice, in diabetic sarcopenia by generating Chrebp-deficient, insulin-deficient Ins2Akita/+ mice. We evaluated Chrebp +/+, Chrebp -/-, Ins2Akita/+ /Chrebp +/+, and Ins2Akita/+ /Chrebp -/- mice for muscle strength, endurance, survival, body composition, and muscle histology. Skeletal muscles were analyzed for gene expressions related to anabolic and catabolic pathways. We found that Ins2Akita/+ /Chrebp -/- mice exhibited significant reductions in body weight, grip strength, survival, and skeletal muscle mass - particularly in the tibialis anterior, soleus, gastrocnemius, and quadriceps - compared to Ins2Akita/+ controls, despite similar hyperglycemia. Histological analysis revealed a smaller mean muscle fiber size and reduced cross-sectional area of type 2A and 2B fibers, without changes in fiber-type composition. Furthermore, Igf-1 expression was suppressed, while the atrophy marker Fbxo32/Atrogin-1 was upregulated. These findings demonstrate that Chrebp deletion exacerbates muscle atrophy and frailty in insulin-deficient mice, underscoring a key role for ChREBP-mediated glucose signaling in maintaining muscle mass under diabetic conditions. The Ins2Akita/+ /Chrebp -/- model provides a valuable platform for exploring diabetic sarcopenia mechanisms and potential therapeutic targets.

Disruptions in iron homeostasis are common during obese states and are related to chronic inflammation and insulin resistance. Exercise exerts well-recognized anti-adiposity and anti-inflammatory effects, besides modulating iron control. The vagus nerve (VN) influences immune and metabolic responses, in a spleen-dependent manner with an unknown impact on iron. Here, we evaluated the effects of the absence of the VN and of the spleen on adiposity, metabolism, and iron homeostasis in non-obese and hypothalamic-obese rats submitted to swimming training. Hypothalamic obesity was induced by the administration of monosodium glutamate (MSG; 4 g/Kg) during the initial postnatal days (PNDs). Non-obese control (CTL) rats received equimolar saline. At PND 60, MSG and CTL were submitted to surgery consisting of bilateral subdiaphragmatic vagotomy (Sv), splenectomy (Spl), Sv + Spl, or sham surgery. At PND 80, the rats were subdivided into exercised (Ex) or sedentary (Sd). Exercised rats swam for 30 min/day for 40 days. At PND 120, the growth, adiposity, metabolism, and iron homeostasis of rats were evaluated. Major results indicate that the absence of the VN and spleen favors the anti-adiposity effects of exercise, particularly in MSG-obese rats. In CTL rats, exercise increased plasma iron, in association with changes in iron transport capacity and a reduction in circulating hepcidin levels, a response that is influenced by the VN and spleen. In contrast, in the MSG-obese animals, vagal and splenic absence resulted in increased hepcidin, including following exercise, via a response that is independent of systemic iron fluctuations, suggesting disturbed hepcidin-iron homeostasis during hypothalamic obesity.

Hyperglycemia is common in extremely preterm infants, and the treatment of neonatal hyperglycemia should be associated with a low risk of hypoglycemia. Incretin-based therapies are characterized by a low risk of hypoglycemia and are efficacious and safe in adults. We aimed to investigate the extent to which the glucose-lowering effect of incretin hormone-enhanced insulin secretion contributes to glucose regulation in healthy, developing rat pups and to evaluate the associated risk of hypoglycemia. We performed oral glucose tolerance (OGTT) and intraperitoneal glucose tolerance test (IPGTT) in 2-week-old Wistar rats and compared the serum concentrations of glucose, insulin, and incretin hormones. OGTT was associated with significantly higher serum incretin hormone concentrations than IPGTT in the pups, and the serum insulin concentrations were higher during OGTT than during IPGTT (the incretin effect was 63%). Thus, the incretin effects were present and substantial in the rat pups. We next administered two drugs (a dipeptidyl peptidase 4 (DPP-4) inhibitor or a glucagon-like peptide 1 (GLP-1) receptor agonist) with incretin effects and evaluated the risk of adverse hypoglycemic events in normal developing rats. Standard therapeutic doses of linagliptin and liraglutide did not influence the blood glucose concentrations of 2-week-old pups, and no hypoglycemia developed. In conclusion, we have shown that endogenous incretin hormones stimulate insulin secretion in normal 2-week-old rats, as in adults. Furthermore, neither a DPP-4 inhibitor nor a GLP-1 receptor agonist induced hypoglycemia as an adverse effect. Therefore, incretin hormones may be safe therapeutic targets for hyperglycemia in preterm infants.