The role of bone in energy metabolism: A focus on osteocalcin.

Understanding the mechanisms involved in whole body glucose regulation is key for the discovery of new treatments for type 2 diabetes (T2D). Historically, glucose regulation was largely focused on responses to insulin and glucagon. Impacts of incretin-based therapies, and importance of muscle mass, are also highly relevant. Recently, bone was recognized as an endocrine organ, with several bone proteins, known as osteokines, implicated in glucose metabolism through their effects on the liver, skeletal muscle, and adipose tissue. Research efforts mostly focused on osteocalcin (OC) as a leading example. This review will provide an overview on this role of bone by discussing bone turnover markers (BTMs), the receptor activator of nuclear factor kB ligand (RANKL), osteoprotegerin (OPG), sclerostin (SCL) and lipocalin 2 (LCN2), with a focus on OC. Since 2007, some, but not all, research using mostly OC genetically modified animal models suggested undercarboxylated (uc) OC acts as a hormone involved in energy metabolism. Most data generated from in vivo, ex vivo and in vitro models, indicate that exogenous ucOC administration improves whole-body and skeletal muscle glucose metabolism. Although data in humans are generally supportive, findings are often discordant likely due to methodological differences and observational nature of that research. Overall, evidence supports the concept that bone-derived factors are involved in energy metabolism, some having beneficial effects (ucOC, OPG) others negative (RANKL, SCL), with the role of some (LCN2, other BTMs) remaining unclear. Whether the effect of osteokines on glucose regulation is clinically significant and of therapeutic value for people with insulin resistance and T2D remains to be confirmed.

Distribution of Serum Testosterone Concentrations in IBD Males and Associations With Inflammatory Bowel Disease Activity.

BACKGROUND: An inverse relationship exists between inflammation and testosterone concentrations in non-inflammatory bowel disease (IBD) immune conditions but has not been objectively explored in the IBD male population. We aimed to characterize the distribution of testosterone concentrations in a cohort of males with IBD and identify any relationship between testosterone levels and disease activity. METHODS: We conducted a prospective cross-sectional study of male IBD patients. Demographics, disease characteristics, sex-hormone concentration, gonadotropins, C-reactive protein, fecal calprotectin, and patient-reported outcomes on quality of life and erectile function were collected. Relationships between disease activity, biomarkers, patient-reported outcome scores, and testosterone levels were analyzed using univariate and multivariate linear regression analyses. RESULTS: A total of 85 male IBD patients were included with a mean age 44 ± 14.1 years, of which 49.4% had Crohn's disease. Mean testosterone concentration was 15.4 ± 5.2 nmol/L and 17.6% had a serum testosterone <10.4 nmol/L. Active disease was associated with lower testosterone concentrations in univariate analysis (ß ± SE = -0.25 ± -1.99, P = .02) but not in multivariate analysis (ß -0.18 ± 1.75, P = .06). Testosterone concentrations were independently associated with sex hormone-binding globulin levels (ß ± SE = 0.45 ± 0.04, P < .0001) and a younger age (ß ± SE = -0.32 ± 0.04, P <.0001). Erectile function scores (5-item International Index of Erectile Function) were lower in IBD patients with a longer duration of disease (ß ± SE = -0.24 ± 0.006, P = .04). CONCLUSIONS: Lower testosterone concentrations in men with IBD may reflect confounding from other factors and are not independently associated with disease activity. Greater awareness and screening for sexual dysfunction should occur in males with IBD, particularly in those with a longer disease duration.

Sexual dysfunction in men with inflammatory bowel disease (IBD) is multifactorial. We explored the underlying hormonal profile of men with IBD and characterized the distribution of testosterone levels. Almost 1 in 5 males with IBD have a level that is considered low by international definitions (<10.4 nmol/L).

Testosterone therapy in older men: clinical implications of recent landmark trials.

Testosterone therapy for men with hypogonadism due to identifiable hypothalamic-pituitary-testicular (HPT) pathology is uncontroversial. However, the risks and benefits of testosterone for men with clinical features of hypogonadism in the absence of identifiable HPT axis pathology have been uncertain. Recent landmark placebo-controlled trials assessed the benefits and risks of testosterone therapy (≤3 years) for middle-aged and older men with symptoms and possible signs of hypogonadism or end-organ androgen deficiency, low or low-normal serum testosterone concentrations, but no HPT pathology: Testosterone therapy (1) had modest-but clinically significant-benefits on average self-reported energy and mood, sexual function, and satisfaction; (2) in conjunction with a lifestyle programme, reversed or reduced incident type 2 diabetes mellitus (T2D) in men at high risk of or newly diagnosed with T2D; (3) modestly improved objectively assessed muscle strength and timed walking distance; (4) increased bone density and strength, but did not reduce falls or typical osteoporotic fractures and surprisingly increased the risk of fractures typically attributable to trauma; and (5) did not significantly increase the risk of myocardial infarction, stroke, or prostate cancer. These landmark trials help to inform clinical decision-making about testosterone therapy for men.

Correction: Testosterone treatment combined with exercise to improve muscle strength, physical function and quality of life in men affected by inclusion body myositis: A randomised, double-blind, placebo-controlled, crossover trial.

[This corrects the article DOI: 10.1371/journal.pone.0283394.].

Testosterone and the risk of incident atrial fibrillation in older men: further analysis of the ASPREE study.

Background: A cardiovascular safety trial of testosterone in men with cardiovascular risk factors or disease found no difference in rates of major adverse cardiovascular events (MACE) or death but noted more atrial fibrillation (AF) events in testosterone-treated men. We investigated the relationship between endogenous testosterone concentrations with risk of developing AF in healthy older men. Methods: Post-hoc analysis of 4570 male participants in the ASPirin in Reducing Events in the Elderly (ASPREE) study. Men were aged ≥ 70 years, had no history of cardiovascular disease (including AF), thyroid disease, prostate cancer, dementia, or life-threatening illnesses. Risk of AF was modelled using Cox proportional hazards regression. Findings: Median (IQR) age was 73.7 (71.6-77.1) years and median (IQR) follow-up 4.4 (3.3-5.5) years, during which 286 men developed AF (15.3 per 1000 participant-years). Baseline testosterone was higher in men who developed incident AF compared men who did not [17.0 (12.4-21.2) vs 15.7 (12.2-20.0) nmol/L]. There was a non-linear association of baseline testosterone with incident AF. The risk for AF was higher in men with testosterone in quintiles (Q) 4&5 (Q4:Q3, HR = 1.91; 95%CI = 1.29-2.83 and Q5:Q3HR = 1.98; 95%CI = 1.33-2.94). Results were similar after excluding men who experienced MACE or heart failure during follow-up. Interpretation: Circulating testosterone concentrations within the high-normal range are independently associated with an increased risk of incident AF amongst healthy older men. This suggests that AF may be an adverse consequence of high-normal total testosterone concentrations. Funding: National Institute on Aging and National Cancer Institute at the National Institutes of Health; Australian Government (NHMRC, CSIRO); Monash University; and AlfredHealth.

Associations of Diabetes and Hyperglycaemia with Extent and Outcomes of Acute Burn Injuries.

BACKGROUND: Severe burns may induce hyperglycaemia in the absence of diabetes, but how glucose trajectories relate to burns outcomes is unclear. AIM: To assess incidence of hyperglycaemia following acute burn injury, and associations with diabetes history and length of stay (LOS). METHODS: Retrospective cohort study of adults admitted with acute burns to tertiary centres. Blood glucose level (BGL), hyperglycaemic episodes (BGL ≥ 11.1 mmol/L) and hyperglycaemic days were recorded. Stress hyperglycaemia was defined as BGL ≥ 11.1 mmol/L without a diabetes history. RESULTS: A total of 30 participants had a diabetes history and 260 did not. Participants with known diabetes had higher mean BGLs (9.7 vs. 9.0 mmol/L, p < 0.001), more hyperglycaemic episodes (28.0 vs. 17.2%, p < 0.001) and hyperglycaemic days (51 vs. 21%, p < 0.001), compared to those without diabetes, despite smaller burns (total body surface area 1.0 vs. 14.8%, p < 0.001). Fourteen participants with stress hyperglycaemia had similar BGLs (at admission 10.3 vs. 11.5 mmol/L; during inpatient stay 9.9 vs. 9.8 mmol/L), more severe burns (15.6% vs. 1.0% TBSA) and longer LOS (18 vs. 7 days, p < 0.001) compared to participants with known diabetes. Extent of burns, having NGT nutrition, age, having inpatient BGL monitoring in the setting of diabetes, or having inpatient BGL monitoring in the absence of diabetes were associated with longer LOS. CONCLUSIONS: In participants with known diabetes, small burn injuries were associated with hyperglycaemia. Stress hyperglycaemia can be triggered by major burn injuries, with early and sustained elevation of BGLs. Further research is warranted to improve inpatient management of BGL in patients with acute burn injury.

Associations of Testosterone and Related Hormones With All-Cause and Cardiovascular Mortality and Incident Cardiovascular Disease in Men : Individual Participant Data Meta-analyses.

BACKGROUND: Whether circulating sex hormones modulate mortality and cardiovascular disease (CVD) risk in aging men is controversial. PURPOSE: To clarify associations of sex hormones with these outcomes. DATA SOURCES: Systematic literature review to July 2019, with bridge searches to March 2024. STUDY SELECTION: Prospective cohort studies of community-dwelling men with sex steroids measured using mass spectrometry and at least 5 years of follow-up. DATA EXTRACTION: Independent variables were testosterone, sex hormone-binding globulin (SHBG), luteinizing hormone (LH), dihydrotestosterone (DHT), and estradiol concentrations. Primary outcomes were all-cause mortality, CVD death, and incident CVD events. Covariates included age, body mass index, marital status, alcohol consumption, smoking, physical activity, hypertension, diabetes, creatinine concentration, ratio of total to high-density lipoprotein cholesterol, and lipid medication use. DATA SYNTHESIS: Nine studies provided individual participant data (IPD) (255 830 participant-years). Eleven studies provided summary estimates (n = 24 109). Two-stage random-effects IPD meta-analyses found that men with baseline testosterone concentrations below 7.4 nmol/L (<213 ng/dL), LH concentrations above 10 IU/L, or estradiol concentrations below 5.1 pmol/L had higher all-cause mortality, and those with testosterone concentrations below 5.3 nmol/L (<153 ng/dL) had higher CVD mortality risk. Lower SHBG concentration was associated with lower all-cause mortality (median for quintile 1 [Q1] vs. Q5, 20.6 vs. 68.3 nmol/L; adjusted hazard ratio [HR], 0.85 [95% CI, 0.77 to 0.95]) and lower CVD mortality (adjusted HR, 0.81 [CI, 0.65 to 1.00]). Men with lower baseline DHT concentrations had higher risk for all-cause mortality (median for Q1 vs. Q5, 0.69 vs. 2.45 nmol/L; adjusted HR, 1.19 [CI, 1.08 to 1.30]) and CVD mortality (adjusted HR, 1.29 [CI, 1.03 to 1.61]), and risk also increased with DHT concentrations above 2.45 nmol/L. Men with DHT concentrations below 0.59 nmol/L had increased risk for incident CVD events. LIMITATIONS: Observational study design, heterogeneity among studies, and imputation of missing data. CONCLUSION: Men with low testosterone, high LH, or very low estradiol concentrations had increased all-cause mortality. SHBG concentration was positively associated and DHT concentration was nonlinearly associated with all-cause and CVD mortality. PRIMARY FUNDING SOURCE: Medical Research Future Fund, Government of Western Australia, and Lawley Pharmaceuticals. (PROSPERO: CRD42019139668).

Comparing the Impacts of Testosterone and Exercise on Lean Body Mass, Strength and Aerobic Fitness in Aging Men.

BACKGROUND: Based on the largely untested premise that it is a restorative hormone that may reverse the detrimental impacts of aging, prescription of testosterone (T) has increased in recent decades despite no new clinical indications. It is apparent that middle-aged and older men with low-normal serum T levels are considering T supplementation as an anti-aging strategy. At the same time, there is evidence that physical activity (PA) is at historical lows in the Western world. In this review, we compare the impacts of T treatment aimed at achieving physiological T concentrations in middle-aged and older men, alongside the impacts of ecologically relevant forms of exercise training. The independent, and possible combined, effects of T and exercise therapy on physiological outcomes such as aerobic fitness, body composition and muscular strength are addressed. MAIN BODY: Our findings suggest that both T treatment and exercise improve lean body mass in healthy older men. If improvement in lean body mass is the primary aim, then T treatment could be considered, and the combination of T and exercise may be more beneficial than either in isolation. In terms of muscle strength in older age, an exercise program is likely to be more beneficial than T treatment (where the dose is aimed at achieving physiological concentrations), and the addition of such T treatment does not provide further benefit beyond that of exercise alone. For aerobic fitness, T at doses aimed at achieving physiological concentrations has relatively modest impacts, particularly in comparison to exercise training, and there is limited evidence as to additive effects. Whilst higher doses of T, particularly by intramuscular injection, may have larger impacts on lean body mass and strength, this must be balanced against potential risks. CONCLUSION: Knowing the impacts of T treatment and exercise on variables such as body composition, strength and aerobic fitness extends our understanding of the relative benefits of physiological and pharmacological interventions in aging men. Our review suggests that T has impacts on strength, body composition and aerobic fitness outcomes that are dependent upon dose, route of administration, and formulation. T treatment aimed at achieving physiological T concentrations in middle-aged and older men can improve lean body mass, whilst exercise training enhances lean body mass, aerobic fitness and strength. Men who are physically able to exercise safely should be encouraged to do so, not only in terms of building lean body mass, strength and aerobic fitness, but for the myriad health benefits that exercise training confers.

Incretin-Based Weight Loss Pharmacotherapy: Can Resistance Exercise Optimize Changes in Body Composition?

This narrative review highlights the degree to which new antiobesity medications based on gut-derived nutrient-stimulated hormones (incretins) cause loss of lean mass, and the importance of resistance exercise to preserve muscle. Glucagon-like peptide 1 receptor agonists (GLP-1RA) induce substantial weight loss in randomized trials, effects that may be enhanced in combination with glucose-dependent insulinotropic polypeptide (GIP) receptor agonists. Liraglutide and semaglutide (GLP-1RA), tirzepatide (GLP-1 and GIP receptor dual agonist), and retatrutide (GLP-1, GIP, and glucagon receptor triple agonist) are peptides with incretin agonist activity that induce ∼15-24% weight loss in adults with overweight and obesity, alongside beneficial impacts on blood pressure, cholesterol, blood glucose, and insulin. However, these agents also cause rapid and significant loss of lean mass (∼10% or ∼6 kg), comparable to a decade or more of aging. Maintaining muscle mass and function as humans age is crucial to avoiding sarcopenia and frailty, which are strongly linked to morbidity and mortality. Studies indicate that supervised resistance exercise training interventions with a duration >10 weeks can elicit large increases in lean mass (∼3 kg) and strength (∼25%) in men and women. After a low-calorie diet, combining aerobic exercise with liraglutide improved weight loss maintenance compared with either alone. Retaining lean mass during incretin therapy could blunt body weight (and fat) regain on cessation of weight loss pharmacotherapy. We propose that tailored resistance exercise training be recommended as an adjunct to incretin therapy to optimize changes in body composition by preserving lean mass while achieving fat loss.

Association of serum phosphate, calcium and alkaline phosphatase with risk of incident fractures in healthy older adults.

BACKGROUND: Aging increases fracture risk through bone loss and microarchitecture deterioration due to an age-related imbalance in bone resorption and formation during bone remodelling. We examined the associations between levels of phosphate, calcium, and alkaline phosphatase, and fracture risk in initially-healthy older individuals. METHODS: A post-hoc analysis of the Aspirin in Reducing Events in the Elderly (ASPREE) trial recruited 16,703 Australian participants aged ≥70 years and 2,411 US participants aged ≥65 years. Analyses were conducted on ASPREE-Fracture substudy participants from Australia with serum calcium, phosphate, and alkaline phosphatase measurement. Fracture data were collected post-randomization. Cox regression was used to calculate hazard ratios (HR) and 95% confidence intervals (CIs). Phosphate, calcium, and alkaline phosphatase were analysed in deciles (D1-D10), with deciles 4-7 (31-70%) as the reference category. Restricted cubic spline curves were used to identify nonlinear associations. RESULTS: Of the 9915 participants, 907 (9·2%) persons had incident fractures recorded over 3·9 (SD 1·4) years. In the fully adjusted model, males in the top decile (D10) of phosphate had 78% higher risk of incident fracture (HR 1·78, 95% CI 1·25-2·54). No such association was observed for females (HR 1·09, 95% CI 0·83-1·44). The population attributable fraction in men within the D10 phosphate category is 6·9%. CONCLUSION: This result confirms that, high-normal serum phosphate levels are associated with increased fracture risk in older men.

Early SGLT2 inhibitor use is associated with improved left atrial strain following acute coronary syndrome.

AIM: Left atrial (LA) strain, a novel marker of LA function, reliably predicts diastolic dysfunction. SGLT2 inhibitors improve heart failure outcomes, but limited data exists regarding their use in the immediate aftermath of acute coronary syndrome (ACS). We studied the effect of empagliflozin on LA strain in patients with type 2 diabetes (T2D) and ACS. METHODS: Patients with ACS and T2D were identified and empagliflozin was initiated in eligible patients prior to discharge. Patients not initiated on empagliflozin were analysed as a comparator group. A blinded investigator assessed LA strain using baseline and 3-6 month follow-up echocardiograms. RESULTS: Forty-four participants (n = 22 each group) were included. Baseline characteristics and LA strain were similar in the two groups. LA reservoir, conduit and contractile strain increased in empagliflozin group (28.0 ± 8.4% to 34.6 ± 12.2% p < 0.001, 14.5 ± 5.4% to 16.7 ± 7.0% p = 0.034, 13.5 ± 5.2% to 17.9 ± 7.2% p = 0.005, respectively) but remained unchanged in comparison group (29.2 ± 6.7% to 28.8 ± 7.0%, 12.8 ± 4.2% to 13.3 ± 4.7%, 16.7 ± 5.3% to 15.5 ± 4.5%, respectively, p = NS). The difference in change between groups was significant for LA reservoir (p = 0.003) and contractile strain (p = 0.005). CONCLUSION: In patients with ACS and T2D, addition of empagliflozin to standard ACS therapy prior to discharge is associated with improved LA function.

Testosterone Treatment, Weight Loss, and Health-related Quality of Life and Psychosocial Function in Men: A 2-year Randomized Controlled Trial.

OBJECTIVE: To determine the effect of testosterone vs placebo treatment on health-related quality of life (HR-QOL) and psychosocial function in men without pathologic hypogonadism in the context of a lifestyle intervention. DESIGN, SETTING, PARTICIPANTS: Secondary analysis of a 2-year randomized controlled testosterone therapy trial for prevention or reversal of newly diagnosed type 2 diabetes, enrolling men ≥ 50 years at high risk for type 2 diabetes from 6 Australian centers. INTERVENTIONS: Injectable testosterone undecanoate or matching placebo on the background of a community-based lifestyle program. MAIN OUTCOMES: Self-reported measures of HR-QOL/psychosocial function. RESULTS: Of 1007 participants randomized into the Testosterone for Type 2 Diabetes Mellitus (T4DM) trial, 648 (64%) had complete data available for all HR-QOL/psychosocial function assessments at baseline and 2 years. Over 24 months, while most measures were not different between treatment arms, testosterone treatment, compared with placebo, improved subjective social status and sense of coherence. Baseline HR-QOL/psychosocial function measures did not predict the effect of testosterone treatment on glycemic outcomes, primary endpoints of T4DM. Irrespective of treatment allocation, larger decreases in body weight were associated with improved mental quality of life, mastery, and subjective social status. Men with better baseline physical function, greater sense of coherence, and fewer depressive symptoms experienced greater associated decreases in body weight, with similar effects on waist circumference. CONCLUSION: In this diabetes prevention trial, weight loss induced by a lifestyle intervention improved HR-QOL and psychosocial function in more domains than testosterone treatment. The magnitude of weight and waist circumference reduction were predicted by baseline physical function, depressive symptomology, and sense of coherence.

Group-based behaviour therapy improves self-care, glycaemic control and distress in adults with type 1 diabetes.

AIMS: Psychological interventions have had modest effects on HbA1c in adults with Type 1 diabetes (T1D). We evaluated a novel behaviour therapy (BT) group program aiming to improve diabetes self-care and reduce HbA1c and distress. Core features were the application of a functional-analytic model, behavioural self-management training, and personally selected T1D self-care behaviours as treatment targets. METHODS: Participants with T1D, 2-consecutive HbA1c ≥ 8.5 %(69 mmol/mol) and/or diabetes-related emotional/behavioural difficulties who had received specialist multidisciplinary input for ≥2 years completed 6-sessions of BT over 9-weeks. Outcomes were assessed at baseline, on completing 5-consecutive weekly sessions (post-) and at session 6, 1-month after (follow-up). RESULTS: Of 66 participants mean age 37.9 years, mean age at T1D diagnosis 22.0 years, and median T1D duration 14 years, 54 completed BT. HbA1c improved from baseline to follow-up (9.7 ± 1.9 %-8.8 ± 1.3 %, p < 0.001), as did diabetes distress (DD: total score 49.2 ± 7.8 baseline, 38.9 ± 14.7 post- and 32.8 ± 11.7 follow-up, p < 0.001). All DD subscales of emotional burden, and physician, regimen, and interpersonal distress, improved (p < 0.001). Consistent results were observed for patients on multiple daily injections and continuous subcutaneous insulin infusion therapy. CONCLUSIONS: BT based on a functional-analytic and behavioural self-management model holds promise as an effective means of improving HbA1c and reducing DD in adults with T1D.