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1.
J Clin Oncol ; : JCO2302309, 2024 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-38954783

RESUMEN

PURPOSE: Suppression of ovarian function and aromatase inhibition (AI) increases disease-free survival in premenopausal women with estrogen receptor (ER)-positive early-stage breast cancer but accelerates bone loss. We therefore hypothesized that suppressing bone remodeling using denosumab (DMAB) would prevent bone loss in these women. METHODS: In a 12-month double-blind randomized trial, 68 women with ER-positive early-stage breast cancer commencing ovarian function suppression and AI were randomly assigned to 60 mg DMAB (n = 34) or placebo (PBO; n = 34) once every 6 months (at 0 and 6 months). Volumetric bone mineral density (BMD), microarchitecture, and estimated bone strength of the distal tibia and distal radius were measured using high-resolution peripheral quantitative computed tomography, and spine and hip BMD were measured using dual-energy X-ray absorptiometry at 0, 6, and 12 months. The primary end point and treatment effect was the mean adjusted between group difference (MAD; [95% CI]) in distal tibial total volumetric BMD over 12 months, with a single P value tested over all time points. The study is registered with the Australian New Zealand Clinical Trials Registry (anzctr.org.au; identifier: ACTRN12616001051437). RESULTS: Intention-to-treat analysis included all 68 randomly assigned women. Over 12 months, compared with PBO, DMAB prevented the decrease in distal tibial total BMD (MAD, 20.8 mg HA/cm3 [95% CI, 17.3 to 24.2]), cortical BMD (42.9 mg HA/cm3 [95% CI, 32.1 to 53.9]), trabecular BMD (3.32 mg HA/cm3 [95% CI, 1.45 to 5.20], P = .004), estimated stiffness (11.6 kN/m [95% CI, 7.6 to 15.6]), and failure load (563 N [95% CI, 388 to 736]). Findings were similar at the distal radius. Decreases in BMD at the lumbar spine (MAD, 0.13 g/cm2 [95% CI, 0.11 to 0.15]), total hip (0.08 g/cm2 [95% CI, 0.07 to 0.09], and femoral neck (0.06 g/cm2 [95% CI, 0.05 to 0.07]) were also prevented. All P < .001 unless otherwise noted. CONCLUSION: Treatment with DMAB at commencement of estradiol suppression therapy preserves BMD, bone microarchitecture, and estimated strength, and is likely to increase fracture-free survival.

2.
J Endocrinol ; 262(1)2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38727510

RESUMEN

The fundamental models underlying hormonal physiological regulation and homeostasis remain poorly understood. We aimed to derive quantitative evidence regarding these models from the study of population data of balance points of different parameters and their respective controlling hormones. We studied the slopes of correlations between concentrations of circulating free thyroxine and thyrotropin, calcium and parathyroid hormone, hemoglobin and erythropoietin, and glucose and insulin in such population data, as well as the slopes of the limbs of various feedback loops estimated empirically and by reverse engineering of the population data. We used computer simulations to model the factors that influence the slopes derived from the population data, and then matched these simulations with the empirically derived slopes. Our simulations showed that changes to the population distribution of feedback loop limbs may alter the slopes of correlations within population data in specific ways. Non-random (interdependent) associations of the limbs of feedback loops may also have this effect, as well as producing discrepancies between the slopes of feedback limb loops determined experimentally and the same slopes determined by derivation from population data. Our corresponding empirical findings were consistent with the presence of such interdependence in the free thyroxine/thyrotropin, hemoglobin/erythropoietin, and glucose/insulin systems. The glucose/insulin data provided evidence consistent with increasing interdependence with age in childhood. Our findings therefore provide strong evidence that the interdependence of the limbs of feedback loops is a general feature of endocrine homeostatic regulation. This interdependence potentially bestows evolutionary homeostatic and regulatory advantages.


Asunto(s)
Glucemia , Retroalimentación Fisiológica , Insulina , Tirotropina , Tiroxina , Humanos , Tiroxina/sangre , Retroalimentación Fisiológica/fisiología , Tirotropina/sangre , Insulina/sangre , Adulto , Masculino , Femenino , Glucemia/metabolismo , Glucemia/análisis , Simulación por Computador , Hormona Paratiroidea/sangre , Persona de Mediana Edad , Niño , Calcio/sangre , Calcio/metabolismo , Adolescente , Eritropoyetina/sangre , Modelos Biológicos , Hemoglobinas/metabolismo , Hemoglobinas/análisis , Anciano , Hormonas/sangre , Homeostasis/fisiología , Adulto Joven
3.
Hepatology ; 2024 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-38442012

RESUMEN

BACKGROUND AND AIMS: Observational studies suggest a beneficial effect of continuous terlipressin infusion (CTI) on ascites and sarcopenia in decompensated cirrhosis with portal hypertension. APPROACH AND RESULTS: This single-center, prospective, cross-over study randomized 30 patients with cirrhosis, ascites, and sarcopenia to commence on 12 weeks of home CTI or 12 weeks of observation prior to cross-over. The co-primary outcomes were change in handgrip strength and paracentesis volume. Secondary outcomes included quality of life, sarcopenia measures, renal function, safety, and hospitalization. The median age of participants was 62 years (IQR: 57-64), the median Model for End-Stage Liver Disease-Sodium was 16 (12.3-20.8), and 22 (73%) were male. Handgrip strength increased by a mean adjusted difference (MAD) of 3.09 kg (95% CI: 1.11-5.08 kg) between CTI and observation ( p =0.006); an 11.8% increase from baseline. The total volume of ascites drained decreased by a MAD of 11.39L (2.99-19.85, p =0.01), with 1.75 fewer episodes of paracentesis (0.925-2.59, p <0.001) on CTI. Serum creatinine decreased, urinary sodium excretion increased, and quality of life was significantly higher on CTI (all p <0.001), with an increase in Chronic Liver Disease Questionnaire score of 0.41 points (0.23-0.59). There were 7 minor line-related complications but no cardiac events or pulmonary edema. CONCLUSIONS: This novel study demonstrates a significant increase in handgrip strength, reduction in paracentesis volume, and improved quality of life in patients with decompensated cirrhosis treated with continuous terlipressin infusion. These findings provide a strong rationale for the use of ambulatory CTI in appropriately selected patients with cirrhosis.

4.
Aliment Pharmacol Ther ; 59(8): 941-952, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38404263

RESUMEN

BACKGROUND: Sarcopenia is associated with adverse outcomes in cirrhosis. Branched-chain amino acids (BCAA) target several pathways that lead to muscle loss in this population. AIMS: We aimed to evaluate the impact of BCAA supplementation on sarcopenia measures in patients with cirrhosis. METHODS: We conducted a 12-month double-blinded, randomised, controlled trial of BCAA supplementation (30 g daily) compared to an equicaloric, equi-nitrogenous whey protein in volunteers with cirrhosis and reduced muscle strength. The primary endpoint was an increase in grip strength and upper limb lean mass measured on DEXA. Mean-adjusted differences (MAD, 95% CI) between groups at 6 and 12 months are reported as treatment effect using a linear mixed model for repeated measures. RESULTS: A total of 150 volunteers entered the trial (74 BCAA, 76 control), with a median age of 58 years [IQR 48; 63] and MELD of 14 [12; 17]. At 12 months, 57% in the BCAA arm and 61% in the control arm met the primary endpoint (p = 0.80). No significant between-group difference was found in grip strength (MAD -0.15 kg [-0.37; 0.06], p = 0.29) or upper limb lean mass (1.7 kg [-0.2; 3.6], p = 0.22) at 12 months. No significant differences in other body composition parameters, physical performance, frailty, rates of hospitalisation or mortality were found between the BCAA and the control group. Fatigue improved across the entire cohort, without significant between-group differences. 15% of volunteers reported side effects, with distaste higher in the BCAA arm (p = 0.045). CONCLUSION: BCAA supplementation did not improve measures of muscle strength, mass or performance or physical frailty compared to a whey protein supplement in a randomised controlled setting. ACTRN12618000802202.


Asunto(s)
Fragilidad , Sarcopenia , Humanos , Persona de Mediana Edad , Sarcopenia/tratamiento farmacológico , Proteína de Suero de Leche/uso terapéutico , Aminoácidos de Cadena Ramificada/uso terapéutico , Cirrosis Hepática/complicaciones , Cirrosis Hepática/tratamiento farmacológico , Suplementos Dietéticos
5.
Nuklearmedizin ; 63(3): 176-187, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38262472

RESUMEN

Radioiodine treatment (RIT) has a high success rate in both the treatment of hyperthyroidism and improving the quality of life (QoL) of symptomatic patients. In asymptomatic patients with subclinical hyperthyroidism thyroid related QoL outcomes are less well known. METHODS: Study aim was to evaluate thyroid-related QoL in patients with subclinical hyperthyroidism mostly due to toxic nodular goitre undergoing RIT, compared to a control group of euthyroid subjects. Study design was monocentric, prospective, controlled. Fifty control subjects were enrolled and 51 RIT patients. Most subjects were examined at least twice at an interval of 6 months, with visits immediately before and 6 months after treatment in the RIT group. QoL was estimated with the ThyPRO questionnaire, using its composite scale as primary outcome. Treatment effect was the mean adjusted difference (MAD) between groups over time, using repeated? measures mixed? effects models. RESULTS: TSH concentrations were lower in the RIT group prior to treatment and recovered thereafter slightly above the level of the control group. Correspondingly, QoL improved significantly after 6 months from a worse level in the RIT group, compared to controls (MAD -10.3 [95% CI -14.9, -5.7], p<0.001). QoL improvements were strong for general items, but less pronounced for the hyperthyroid domain. Compared to controls, thyroid volume, thyroid functional capacity (SPINA-GT) and deiodinase activity (SPINA-GD) were significantly reduced in the RIT group. CONCLUSION: Patients with subclinical hyperthyroidism improve both biochemically and in their QoL after RIT, compared to controls. QoL assessment should have a wider role in clinical practice to complement biochemical tests and help with treatment decisions.


Asunto(s)
Hipertiroidismo , Radioisótopos de Yodo , Calidad de Vida , Humanos , Hipertiroidismo/radioterapia , Radioisótopos de Yodo/uso terapéutico , Femenino , Masculino , Estudios Prospectivos , Persona de Mediana Edad , Resultado del Tratamiento , Adulto , Radiofármacos/uso terapéutico
6.
Artículo en Inglés | MEDLINE | ID: mdl-38181438

RESUMEN

CONTEXT: Menopause is associated with changes in musculoskeletal, body composition, and metabolic parameters that may be amplified in premenopausal women receiving estradiol suppression for breast cancer. Denosumab offsets deleterious skeletal effects of estradiol suppression and has been reported to have effects on body composition and metabolic parameters in pre-clinical and observational studies, though evidence from double-blind randomized controlled trials is limited. OBJECTIVE: To assess the effect of denosumab on body composition and metabolic parameters. METHODS: In a pre-specified secondary analysis of a 12-month randomized, double-blind, placebo-controlled trial, 68 premenopausal women with breast cancer initiating ovarian function suppression and aromatase inhibition were randomized to denosumab 60-mg or placebo administered at baseline and 6 months. Outcome measures were total and regional fat and lean mass (DXA), body mass index (BMI), waist and hip circumference, fasting glucose, HOMA-IR, and lipid profile. Using a mixed model, between-group mean adjusted differences, MAD, [95% confidence interval], over time are reported. RESULTS: Over 12 months, relative to placebo, android and gynoid fat mass decreased in the denosumab group (-266 g [95%CI -453 to -79], P = 0.02, and -452 g [95%CI -783 to -122], P = 0.03, respectively). Total fat mass and waist circumference were lower in the denosumab group but not significantly so (-1792g [95% CI -3346 to -240], P = 0.08 and (- 3.77 cm [95% CI -6.76 to -0.79], P = 0.06, respectively). No significant treatment effects were detected in lean mass, BMI, hip circumference, fasting glucose, HOMA-IR, or lipid profile. CONCLUSIONS: In premenopausal women receiving estradiol suppression, denosumab decreases some measures of fat mass with no detectable effects on other measures of body composition or metabolic parameters.

8.
Endocr Connect ; 12(10)2023 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-37522858

RESUMEN

Purpose: We previously demonstrated that 12 months of aromatase inhibitor (AI) treatment was not associated with a difference in body composition or other markers of cardiometabolic health when compared to controls. Here we report on the pre-planned extension of the study. The pre-specified primary hypothesis was that AI therapy for 24 months would lead to increased visceral adipose tissue (VAT) area when compared to controls. Methods: We completed a 12-month extension to our prospective 12-month cohort study of 52 women commencing AI treatment (median age 64.5 years) and 52 women with breast pathology not requiring endocrine therapy (63.5 years). Our primary outcome of interest was VAT area. Secondary and exploratory outcomes included other measures of body composition, hepatic steatosis, measures of atherosclerosis and vascular reactivity. Using mixed models and the addition of a fourth time point, we increased the number of study observations by 79 and were able to rigorously determine the treatment effect. Results: Among study completers (AI = 39, controls = 40), VAT area was comparable between groups over 24 months, the mean-adjusted difference was -1.54 cm2 (95% CI: -14.9; 11.9, P = 0.79). Both groups demonstrated parallel and continuous increases in VAT area over the observation period that did not diverge or change between groups. No statistically significant difference in our secondary and exploratory outcomes was observed between groups. Conclusions: While these findings provide reassurance that short-to-medium-term exposure to AI therapy is not associated with metabolically adverse changes when compared to controls, risk evolution should be less focussed on the AI-associated effect and more on the general development of cardiovascular risk over time.

9.
Ther Adv Endocrinol Metab ; 14: 20420188231158163, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36936128

RESUMEN

Background: Thyroid hormones are controlled by the hypothalamic-pituitary-thyroid (HPT) axis through a complex network of regulatory loops, involving the hormones TRH, TSH, FT4, and FT3. The relationship between TSH and FT4 is widely used for diagnosing thyroid diseases. However, mechanisms of FT3 homeostasis are not well understood. Objective: We used mathematical modelling to further examine mechanisms that exist in the HPT axis regulation for protecting circulating FT3 levels. Methods: A mathematical model consisting of a system of four coupled first-order parameterized non-linear ordinary differential equations (ODEs) was developed, accounting for the interdependencies between the hormones in the HPT axis regulation. While TRH and TSH feed forward to the pituitary and thyroid, respectively, FT4 and FT3 feed backward to both the pituitary and hypothalamus. Stable equilibrium solutions of the ODE system express homeostasis for a particular variable, such as FT3, if this variable stays in a narrow range while certain other parameter(s) and system variable(s) may vary substantially. Results: The model predicts that (1) TSH-feedforward protects FT3 levels if the FT4 production rate declines and (2) combined negative feedback by FT4 and FT3 on both TSH and TRH production rates keeps FT3 levels insensitive to moderate changes in FT4 production rates and FT4 levels. The optimum FT4 and FT3 feedback and TRH and TSH-feedforward ranges that preserve FT3 homeostasis were found by numerical continuation analysis. Model predictions were in close agreement with clinical studies and individual patient examples of hypothyroidism and hyperthyroidism. Conclusions: These findings further extend the concept of HPT axis regulation beyond TSH and FT4 to integrate the more active sister hormone FT3 and mechanisms of FT3 homeostasis. Disruption of homeostatic mechanisms leads to disease. This provides a perspective for novel testable concepts in clinical studies to therapeutically target the disruptive mechanisms.

10.
Endocrine ; 79(1): 143-151, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36115005

RESUMEN

OBJECTIVES: The sensitivities of the pituitary to thyroxine feedback, and the thyroid to thyrotropin stimulation determine the free thyroxine /thyrotropin feedback loop and can be described mathematically by two curves. It is not well understood how the two curves combine in a healthy population with normal thyroid function to express the individual balance points that are observed. This study was directed at this issue testing the possibilities of random combination and directed linkage between the two curves. METHODS: We reverse-engineered two sets of population data, on the assumption of independent combinations of thyroid and pituitary sensitivities, to obtain estimates of the curve describing thyroid sensitivity. Sensitivity studies were performed. RESULTS: No analysis resulted in a physiologically feasible estimate of the curve describing thyroid sensitivity. There was evidence of linkage of the two curves in terms of their combination throughout the normal range. Thyroid response curves reflecting a low free thyroxine response to thyrotropin tended to be combined in individuals with thyrotropin curves reflecting a high thyrotropin response to free thyroxine, and vice versa. CONCLUSIONS: Thyroid and pituitary sensitivities are linked, being combined in individuals in a non-random directed pattern. Direct mutual interaction may contribute to this linkage. This linkage precludes the derivation of the curves describing these sensitivities from population data of the free thyroxine and thyrotropin relationship and complicates their derivation by physiological experimentation. This linkage and probable interaction may also bestow evolutionary advantage by minimising inter-individual variation in free thyroxine levels and by augmenting homeostasis.


Asunto(s)
Glándula Tiroides , Tiroxina , Humanos , Glándula Tiroides/fisiología , Hormonas Tiroideas , Tirotropina , Hipófisis , Triyodotironina
11.
Clin Endocrinol (Oxf) ; 98(2): 190-201, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36271726

RESUMEN

OBJECTIVE: Aromatase inhibitor (AI) therapy provides oncological benefits in postmenopausal women with oestrogen receptor-positive breast cancer. However, AI treatment has been associated with increased cardiovascular risk. In nonbreast cancer populations, experimentally induced low oestrogen states and natural transition to menopause have been associated with increases in visceral adipose tissue (VAT), a known surrogate marker for cardiometabolic risk. Given that AI treatment blocks oestradiol production, we hypothesized that AI treatment would increase VAT. METHODS: We conducted a prospective 12-month cohort study of 52 postmenopausal women newly initiating AI treatment (median age: 64.5 years) and 52 women with breast pathology not requiring endocrine therapy (median age: 63.5 years). VAT area and other body composition parameters were measured at baseline, 6 months and 12 months using dual X-ray absorptiometry. Other risk markers of cardiometabolic health were also assessed. RESULTS: In women initiating AI treatment, there was no statistically significant difference in VAT area after 12 months when compared to controls, with a mean adjusted difference of -5.00 cm2 (-16.9, 6.91), p = .55. Moreover, changes in total fat mass, lean mass, subcutaneous adipose tissue area, hepatic steatosis and measures in endothelial function were also not statistically different between groups after 12 months. Findings were similar after adjustments for activity levels and coronavirus disease 2019 lockdown duration. CONCLUSIONS: These data provide reassurance that over the initial 12 months of AI therapy, AI treatment is not associated with metabolically adverse changes in body composition, hepatic steatosis or vascular reactivity. The impact of extended AI therapy on cardiometabolic health requires further study.


Asunto(s)
Neoplasias de la Mama , COVID-19 , Enfermedades Cardiovasculares , Femenino , Humanos , Persona de Mediana Edad , Neoplasias de la Mama/tratamiento farmacológico , Inhibidores de la Aromatasa/uso terapéutico , Posmenopausia , Estudios de Cohortes , Estudios Prospectivos , Grasa Intraabdominal , Control de Enfermedades Transmisibles , Enfermedades Cardiovasculares/inducido químicamente , Tejido Adiposo
12.
World J Transplant ; 12(6): 120-130, 2022 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-35979539

RESUMEN

BACKGROUND: Pre-transplant muscle wasting measured by computed tomography has been associated with adverse clinical outcomes after liver transplantation including increased rates of sepsis and hospitalisation days. Upper limb lean mass (LM) measured by dual-energy X-ray absorptiometry (DEXA) was recently identified as a novel predictor of sarcopenia-associated mortality in men waitlisted for transplantation. AIM: To investigate the use of DEXA LM in predicting gender-stratified early post-transplant outcomes. METHODS: Liver transplant recipients who underwent pre-transplant DEXA body composition imaging between 2002 and 2017 were included. Endpoints included post-transplant mortality and graft failure, bacterial infections, acute cellular rejection (ACR) and intensive care and total hospital length of stay. RESULTS: Four hundred and sixty-nine patients met inclusion criteria of which 338 were male (72%). Median age was 55.0 years (interquartile range 47.4, 59.7) and model for end-stage liver disease (MELD) score 16. Median time from assessment to transplantation was 7 mo (3.5, 12). Upper limb LM was inversely associated with bacterial infections at 180 d post-transplant (hazard ratio = 0.42; 95% confidence interval: 0.20-0.89; P = 0.024) in males only. There was a negative correlation between upper limb LM and intensive care (τb = -0.090, P = 0.015) and total hospital length of stay (τb = -0.10, P = 0.0078) in men. In women, neither MELD nor body composition parameters were associated with post-transplant adverse outcomes or increased length of stay. Body composition parameters, MELD and age were not associated with 90-d mortality or graft failure in either gender. There were no significant predictors of early ACR. CONCLUSION: Sarcopenia is an independent and potentially modifiable predictor of increased post-transplant bacterial infections and hospital length of stay in men with cirrhosis. DEXA upper limb LM provides a novel measure of muscle wasting that has prognostic value in this cohort. The lack of association in women requires further investigation.

13.
Eur J Endocrinol ; 187(2): 241-256, 2022 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-35666800

RESUMEN

Objective: In men, many effects of testosterone (T) on the skeleton are thought to be mediated by estradiol (E2), but trial evidence is largely lacking. This study aimed to determine the effects of E2 on bone health in men in the absence of endogenous T. Design: This study is a 6-month randomized, placebo-controlled trial with the hypothesis that E2 would slow the decline of volumetric bone mineral density (vBMD) and bone microstructure, maintain areal bone mineral density (aBMD), and reduce bone remodelling. Methods: 78 participants receiving androgen deprivation therapy for prostate cancer were randomized to 0.9 mg of 0.1% E2 gel daily or matched placebo. The outcome measures were vBMD and microarchitecture at the distal tibia and distal radius by high-resolution peripheral quantitative CT, aBMD at the spine and hip by dual-energy x-ray absorptiometry, and serum bone remodelling markers. Results: For the primary endpoint, total vBMD at the distal tibia, there was no significant difference between groups, mean adjusted difference (MAD) 2.0 mgHA/cm3 (95% CI: -0.8 to 4.8), P = 0.17. Cortical vBMD at the distal radius increased in the E2 group relative to placebo, MAD 14.8 mgHA/cm3 (95% CI: 4.5 to 25.0), P = 0.005. Relative to placebo, E2 increased estimated failure load at tibia, MAD 250 N (95% CI: 36 to 465), P = 0.02, and radius, MAD 193 N (95% CI: 65 to 320), P = 0.003. Relative to placebo, E2 increased aBMD at the lumbar spine, MAD 0.02 g/cm2 (95% CI: 0.01 to 0.03), P = 0.01, and ultra-distal radius, MAD 0.01 g/cm2 (95% CI: 0.00 to 0.02), P = 0.01, and reduced serum bone remodelling markers. Conclusion: Relative to placebo, E2 treatment increases some measures of bone density and bone strength in men and reduces bone remodelling, effects that occur in the absence of endogenous T.


Asunto(s)
Antagonistas de Andrógenos , Neoplasias de la Próstata , Absorciometría de Fotón , Antagonistas de Andrógenos/efectos adversos , Andrógenos/farmacología , Densidad Ósea , Estradiol/farmacología , Estradiol/uso terapéutico , Humanos , Masculino , Radio (Anatomía)/diagnóstico por imagen , Tibia
14.
Front Endocrinol (Lausanne) ; 13: 825107, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35757421

RESUMEN

Endocrine regulation in the hypothalamic-pituitary-thyroid (HPT) axis is orchestrated by physiological circuits which integrate multiple internal and external influences. Essentially, it provides either of the two responses to overt biological challenges: to defend the homeostatic range of a target hormone or adapt it to changing environmental conditions. Under certain conditions, such flexibility may exceed the capability of a simple feedback control loop, rather requiring more intricate networks of communication between the system's components. A new minimal mathematical model, in the form of a parametrized nonlinear dynamical system, is here formulated as a proof-of-concept to elucidate the principles of the HPT axis regulation. In particular, it allows uncovering mechanisms for the homeostasis of the key biologically active hormone free triiodothyronine (FT3). One mechanism supports the preservation of FT3 homeostasis, whilst the other is responsible for the adaptation of the homeostatic state to a new level. Together these allow optimum resilience in stressful situations. Preservation of FT3 homeostasis, despite changes in FT4 and TSH levels, is found to be an achievable system goal by joining elements of top-down and bottom-up regulation in a cascade of targeted feedforward and feedback loops. Simultaneously, the model accounts for the combination of properties regarded as essential to endocrine regulation, namely sensitivity, the anticipation of an adverse event, robustness, and adaptation. The model therefore offers fundamental theoretical insights into the effective system control of the HPT axis.


Asunto(s)
Tirotropina , Tiroxina , Sistema Hipotálamo-Hipofisario/fisiología , Glándula Tiroides/fisiología , Triyodotironina
15.
Trials ; 23(1): 335, 2022 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-35449020

RESUMEN

BACKGROUND: Current hyponatraemia guidelines are divided on the use of tolvaptan in hospitalised patients with moderate to severe hyponatraemia, due to an uncertain risk-benefit ratio. We will conduct a randomised trial to test the hypothesis that early use of tolvaptan improves the rate of serum sodium correction and clinical outcomes compared with current standard first-line therapy, restriction of fluid intake, without increasing the risk of serum sodium overcorrection. METHODS: We will enrol hospitalised patients with euvolaemic or hypervolaemic hyponatraemia and serum sodium of 115-130 mmol/L at Austin Health, a tertiary care centre in Melbourne, Australia. Participants will be randomised 1:1 to receive either tolvaptan (initial dose 7.5 mg) or fluid restriction (initial limit 1000 ml per 24 h), with titration of therapy based on serum sodium response according to a pre-determined protocol over a 72-h intervention period. The primary endpoint will be the between-group change in serum sodium over time, from study day 1 to day 4. Secondary endpoints include serum sodium increment in the first 24 and 48 h, proportion of participants with normalised serum sodium, length of hospital stay, requirement for serum sodium re-lowering with intravenous dextrose or desmopressin, cognitive and functional measures (Confusion Assessment Method Short form, Timed Up and Go test, hyponatraemia symptom questionnaire), 30-day readmission rate, treatment satisfaction score and serum sodium 30 days after discharge. The trial will be overseen by an independent Data Safety Monitoring Board. Serum sodium will be monitored every 6-12 h throughout the study period, with pre-specified thresholds for commencing intravenous 5% dextrose if serum sodium rise targets are exceeded. DISCUSSION: We seek to inform future international guidelines with high-quality data regarding the utility and safety of tolvaptan compared to standard therapy fluid restriction in patients with moderate-severe hyponatraemia in hospital. If tolvaptan use in this patient group is endorsed by our findings, we will have established an evidence-based framework for tolvaptan initiation and monitoring to guide its use. TRIAL REGISTRATION: Australia and New Zealand Clinical Trials Registry ACTRN12619001683123 . Registered on December 2 2019.


Asunto(s)
Hiponatremia , Antagonistas de los Receptores de Hormonas Antidiuréticas/efectos adversos , Glucosa/uso terapéutico , Humanos , Hiponatremia/diagnóstico , Hiponatremia/tratamiento farmacológico , Equilibrio Postural , Sodio , Estudios de Tiempo y Movimiento , Tolvaptán/efectos adversos
16.
Clin Endocrinol (Oxf) ; 97(5): 622-633, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-35150156

RESUMEN

OBJECTIVE: Roles for estradiol in modulating cognition in men remain uncertain. We assessed the isolated effects of estradiol on cognition in men in the absence of testosterone. DESIGN: Randomized trial of transdermal estradiol 0.9 mg daily, or matched placebo, for 6 months, hypothesizing that estradiol would improve verbal learning, verbal memory, and spatial problem solving over time. PATIENTS: Men receiving androgen deprivation therapy (ADT) for prostate cancer. MEASUREMENTS: Cognition was assessed by a tablet-based cognitive battery (Cogstate) at baseline, Month 1, Month 3, and Month 6. Anxiety and depression symptoms were assessed using the Hospital Anxiety and Depression Scale. RESULTS: Seventy-eight participants were randomized. Baseline mean scores were 21.0 (standard deviation [SD] 4.1) for the International Shopping List test (ISL), assessing verbal learning and memory (higher scores better), and 60.4 (SD 19.5) for the Groton Maze Learning test (GML), assessing spatial problem solving (lower scores better). There was no significant difference in performance over time for the estradiol group versus the placebo group for the ISL, mean adjusted difference (MAD) 0.7 (95% confidence interval [CI] -1.2 to 2.5), p = .36, or the GML, MAD -3.2 (95% CI -12.0 to 5.6), p = 0.53. There was no significant difference between groups over time in performance in any other cognitive domain, or on depression or anxiety scores. CONCLUSIONS: We found no major effects of estradiol on cognition in men with castrate testosterone concentrations. Although the cognitive effects of ADT are debated, this study suggests that any such effects are unlikely to be prevented by the administration of estradiol.


Asunto(s)
Estradiol , Neoplasias de la Próstata , Antagonistas de Andrógenos/uso terapéutico , Andrógenos/uso terapéutico , Cognición , Estradiol/uso terapéutico , Humanos , Masculino , Neoplasias de la Próstata/tratamiento farmacológico , Testosterona
17.
Eur J Endocrinol ; 187(5): 617-627, 2022 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-36806623

RESUMEN

OBJECTIVE: Most men undergoing androgen deprivation therapy (ADT) for prostate cancer experience hot flushes. Current treatments have low or limited evidence of efficacy. It is likely that oestradiol depletion is the mediator of these hot flushes, and transdermal oestradiol might be an effective treatment. DESIGN: This is a 6-month randomised, placebo-controlled trial with the hypothesis that oestradiol would reduce hot flush frequency and intensity and improve quality of life (QoL). METHODS: Seventy-eight participants receiving ADT were randomised to 0.9 mg of 0.1% oestradiol gel per day or matched placebo. Hot flush frequency and severity were assessed by 7-day diary at baseline, month 1, month 3, and month 6. QoL was assessed by validated questionnaire. RESULTS: Oestradiol reduced daily hot flush frequency, with a mean adjusted difference (MAD) of -1.6 hot flushes per day (95% CI: -2.7 to -0.5; P = 0.04). The effect on weekly hot flush score was non-significant, with a MAD -19.6 (95% CI: -35.5 to -3.8; P = 0.11). On per protocol analysis, E2 significantly reduced daily hot flush frequency, with a MAD of -2.2 hot flushes per day (95% CI: -3.2 to -1.1; P = 0.001), and weekly hot flush score, with a MAD of -27.0 (-44.7 to -9.3; P = 0.02). Oestradiol had no significant effect on QoL. CONCLUSION: We confirmed our hypothesis of a clinical effect of assignment to oestradiol to reduce hot flush frequency in men with castrate testosterone due to ADT. Transdermal oestradiol could be considered for men with burdensome hot flushes in whom other treatments have failed as long as the risk of breast effects and fat gain are considered.


Asunto(s)
Estradiol , Neoplasias de la Próstata , Masculino , Humanos , Estradiol/uso terapéutico , Neoplasias de la Próstata/tratamiento farmacológico , Antagonistas de Andrógenos/uso terapéutico , Calidad de Vida , Andrógenos/uso terapéutico , Sofocos/tratamiento farmacológico , Encuestas y Cuestionarios
18.
Eur J Endocrinol ; 186(1): 9-23, 2021 Nov 30.
Artículo en Inglés | MEDLINE | ID: mdl-34678758

RESUMEN

OBJECTIVE: Indirect evidence suggests that the effects of testosterone on fat mass in men are dependent on aromatization to estradiol (E2). However, no controlled study has assessed the effects of E2 in the absence of testosterone. DESIGN: Six-month randomized, placebo-controlled trial with the hypothesis that men randomized to E2 would reduce their fat mass. METHODS: Seventy-eight participants receiving androgen deprivation therapy for prostate cancer were randomized to 0.9 mg of 0.1% E2 gel per day, or matched placebo. Dual x-ray absorptiometry body composition was measured at baseline, month 3, and month 6. The primary outcome was total fat mass. RESULTS: Serum E2 increased in the estradiol group over 6 months compared to placebo, and mean-adjusted difference (MAD) was 207 pmol/L (95% CI: 123-292), P < 0.001. E2 treatment changed total fat mass, MAD 1007 g (95% CI: 124-1891), but not significantly, so P = 0.09. There were other consistent non-significant trends toward increased proportional fat mass, MAD 0.8% (95% CI: 0.0-1.6), P= 0.15; gynoid fat, MAD 147 g (95% CI: 2-293), P = 0.08; visceral fat, 53 g (95% CI: 1-105) P = 0.13; and subcutaneous fat, MAD 65 g (95% CI: 5-125), P = 0.11. Android fat increased, MAD 164 g (95% CI: 41-286), P = 0.04. CONCLUSION: Contrary to our hypothesis, we provide suggestive evidence that E2 acting in the absence of testosterone, may increase total and regional fat mass in men. Given the premature closure of clinical trials due to the COVID pandemic, this potentially important observation should encourage additional studies to confirm or refute whether E2 promotes fat expansion in the absence of testosterone.


Asunto(s)
Tejido Adiposo/efectos de los fármacos , Antagonistas de Andrógenos/uso terapéutico , Estradiol/farmacología , Absorciometría de Fotón , Anciano , Antagonistas de Andrógenos/efectos adversos , Australia , Composición Corporal/efectos de los fármacos , Método Doble Ciego , Humanos , Masculino , Persona de Mediana Edad , Obesidad/complicaciones , Obesidad/tratamiento farmacológico , Neoplasias de la Próstata/complicaciones , Neoplasias de la Próstata/tratamiento farmacológico
20.
Ther Adv Endocrinol Metab ; 12: 20420188211012118, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34104395

RESUMEN

BACKGROUND: Animal studies suggest that undercarboxylated osteocalcin may improve insulin sensitivity via its effect on testicular testosterone production. Human studies have been conflicting. Men undergoing androgen deprivation therapy (ADT) for prostate cancer experience profound hypogonadism resulting in increased insulin resistance. In a randomised controlled trial (RCT) of zoledronic acid versus placebo in men commencing extended-duration ADT, we aimed to examine the effects on fat mass and glucose metabolism. We hypothesised that zoledronic acid, which reduces osteocalcin concentrations, would worsen ADT-induced insulin resistance. METHODS: This was a prespecified secondary analysis of an RCT designed to evaluate the effects of zoledronic acid on bone microarchitecture in 76 men with non-metastatic prostate cancer undergoing curative radiotherapy combined with adjuvant ADT (n = 39 randomised to a single dose of zoledronic acid 5 mg, n = 37 randomised to matching placebo). Oral glucose tolerance tests to determine Matsuda Index were performed at 0, 3, 12 and 24 months. Using a mixed model, mean adjusted differences [MAD (95% confidence interval)] between the groups over time are reported. RESULTS: Over 24 months of ADT, fat mass increased and lean mass decreased for both groups, with no significant between group difference [MAD 401 g (-1307; 2103), p = 0.23 and -184 g (-1325; 955), p = 0.36 respectively]. Bone remodelling markers C-telopeptide [MAD -176 ng/l (-275; -76), p < 0.001 and P1NP -18 mg/l (-32; -5), p < 0.001] as a surrogate for osteocalcin, remained significantly lower in the zoledronic acid group, compared with placebo. There was no mean adjusted between-group difference for homeostatic model assessment 2 insulin resistance (HOMA2-IR) [-0.2 (-0.6; 0.2), p = 0.45], HbA1c [-0.1% (-0.3; 0.1), p = 0.64] or Matsuda Index [0.8 (-1.1; 2.7), p = 0.38]. The Matsuda Index decreased in both groups consistent with worsening insulin resistance with ADT. CONCLUSION: A single dose of zoledronic acid does not appear to influence glucose metabolism in men newly commencing ADT. Further study to evaluate the endocrine relationship between bisphosphonates, bone and glucose metabolism is required. TRIAL REGISTRATION NUMBER: [ClinicalTrials.gov identifier: NCT01006395].

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