Long-term male fertility after treatment with radioactive iodine for differentiated thyroid carcinoma

Context: Whilst radioactive iodine (RAI) is often administered in the treatment for differentiated thyroid carcinoma (DTC), long-term data on male fertility after RAI are scarce. Objective: To evaluate long-term male fertility after RAI for DTC, and to compare semen quality before and after RAI. Design, setting, and patients: Multicenter study including males with DTC ≥2 years after their final RAI treatment with a cumulative activity of ≥3.7 GBq. Main outcome measure(s): Semen analysis, hormonal evaluation, and a fertility-focused questionnaire. Cut-off scores for 'low semen quality' were based on reference values of the general population as defined by the World Health Organization (WHO). Results: Fifty-one participants had a median age of 40.5 (interquartile range (IQR): 34.0-49.6) years upon evaluation and a median follow-up of 5.8 (IQR: 3.0-9.5) years after their last RAI administration. The median cumulative administered activity of RAI was 7.4 (range: 3.7-23.3) GBq. The proportion of males with a low semen volume, concentration, progressive motility, or total motile sperm count did not differ from the 10th percentile cut-off of a general population (P = 0.500, P = 0.131, P = 0.094, and P = 0.500, respectively). Cryopreserved semen was used by 1 participant of the 20 who had preserved semen. Conclusions: Participants had a normal long-term semen quality. The proportion of participants with low semen quality parameters scoring below the 10th percentile did not differ from the general population. Cryopreservation of semen of males with DTC is not crucial for conceiving a child after RAI administration but may be considered in individual cases

Bone Mineral Density in Adult Survivors of Pediatric Differentiated Thyroid Carcinoma:A Longitudinal Follow-Up Study

Background: Survivors of pediatric differentiated thyroid carcinoma (DTC) receive thyrotropin-suppressive therapy to minimize disease recurrence. However, knowledge about long-term effects of subclinical hyperthyroidism on bone mineral density (BMD) in pediatric DTC survivors is scarce, as is the information regarding long-term consequences of permanent hypoparathyroidism on BMD. We evaluated BMD in pediatric DTC survivors and investigated if BMD was affected by subclinical hyperthyroidism and/or permanent hypoparathyroidism during long-term follow-up. Methods: In this nationwide longitudinal study, we determined BMD in the lumbar spine and femur by dual energy X-ray absorptiometry in 65 pediatric DTC survivors. Measurements were repeated after minimal 5 years of follow-up in 46 pediatric DTC survivors. BMD results were evaluated according to the recommendations of the International Society for Clinical Densitometry (ISCD) and WHO. At both visits, we determined biochemical parameters and markers of bone resorption (C-terminal telopeptide of type I collagen [β-CTX]) and formation (N-propeptide of type I collagen [PINP] and osteocalcin). Results: First and second BMD measurements were done after a median follow-up of 17.0 (interquartile range [IQR] 8.0-25.0) and 23.5 (IQR 14.0-30.0) years after diagnosis, respectively. Median age at diagnosis was 15 years (IQR 13.0-17.0). Twenty-nine percent of the survivors had subclinical hyperthyroidism. In most survivors, BMD T-and Z-scores were within the reference range during both BMD evaluations. However, after 23.5 years of follow-up, a low BMD was found in 13.0%. In the 13 survivors with permanent hypoparathyroidism, BMD values did not differ after 5 years of follow-up compared with baseline values or in comparison with the 33 survivors without permanent hypoparathyroidism. During follow-up, turnover markers β-CTX and PINP remained stable. Conclusions: This longitudinal study of pediatric DTC survivors demonstrated normal and stable median lumbar spine and femur BMD values after a median time of 17 and 23.5 years after diagnosis. However, compared with controls, a lower BMD was still found in 13.0% after prolonged follow-up despite intensive follow-up. Based on the studied follow-up period, these data do not provide convincing evidence in support of standard monitoring of bone mass among DTC survivors, but may be restricted to individual cases at low frequency. Trial Registration: This follow-up study was registered in The Netherlands Trial Register under no. NL3280 (www.trialregister.nl/trial/3280)

Sixteen hours of fasting differentially affects hepatic and muscle insulin sensitivity in mice

Fasting readily induces hepatic steatosis. Hepatic steatosis is associated with hepatic insulin resistance. The purpose of the present study was to document the effects of 16 h of fasting in wild-type mice on insulin sensitivity in liver and skeletal muscle in relation to 1) tissue accumulation of triglycerides (TGs) and 2) changes in mRNA expression of metabolically relevant genes. Sixteen hours of fasting did not show an effect on hepatic insulin sensitivity in terms of glucose production in the presence of increased hepatic TG content. In muscle, however, fasting resulted in increased insulin sensitivity, with increased muscle glucose uptake without changes in muscle TG content. In liver, fasting resulted in increased mRNA expression of genes promoting gluconeogenesis and TG synthesis but in decreased mRNA expression of genes involved in glycogenolysis and fatty acid synthesis. In muscle, increased mRNA expression of genes promoting glucose uptake, as well as lipogenesis and β-oxidation, was found. In conclusion, 16 h of fasting does not induce hepatic insulin resistance, although it causes liver steatosis, whereas muscle insulin sensitivity increases without changes in muscle TG content. Therefore, fasting induces differential changes in tissue-specific insulin sensitivity, and liver and muscle TG contents are unlikely to be involved in these changes

PYY3-36 reinforces insulin action on glucose disposal in mice fed a high-fat diet

Peptide YY3-36 (PYY3-36) is released by the gut in response to nutrient ingestion. It modulates the activities of orexigenic neuropeptide Y (NPY) neurons and anorexigenic proopiomelanocortin (POMC) neurons in the hypothalamus to inhibit food intake. Because both NPY and POMC have also been shown to impact insulin action, we wondered whether PYY3-36 could improve insulin sensitivity. To address this question, we examined the acute effect of intravenous PYY3-36 on glucose and free fatty acid (FFA) flux during a hyperinsulinemic-euglycemic clamp in mice maintained on a high-fat diet for 2 weeks before the experiment. We also evaluated the effects of PYY3-36 infusion on glucose uptake in muscle and adipose tissue in this experimental context. Under basal conditions, none of the metabolic parameters were affected by PYY3-36. Under hyperinsulinemic conditions, glucose disposal was significantly increased in PYY 3-36-infused compared with vehicle-infused mice (103.8 ± 10.9 vs. 76.1 ± 11.4 μmol · min-1 · kg -1, respectively; P = 0.001). Accordingly, glucose uptake in muscle and adipose tissue was greater in PYY3-36-treated animals, although the difference with controls did not reach statistical significance in adipose tissue (muscle: 2.1 ± 0.5 vs. 1.5 ± 0.5 μmol/g tissue, P = 0.049; adipose tissue: 0.8 ± 0.4 vs. 0.4 ± 0.3 μmol/g tissue, P = 0.08). In contrast, PYY3-36 did not impact insulin action on endogenous glucose production or FFA metabolism. These data indicate that PYY3-36 reinforces insulin action on glucose disposal in mice fed a high-fat diet, through a mechanism that is independent of food intake and body weight. In contrast, it leaves glucose production and lipid flux largely unaffected in this experimental context

Chronic PYY3-36 treatment promotes fat oxidation and ameliorates insulin resistance in C57BL6 mice

PYY3-36 is a gut-derived hormone acting on hypothalamic nuclei to inhibit food intake. We recently showed that PYY3-36 acutely reinforces insulin action on glucose disposal in mice. We aimed to evaluate effects of PYY3-36 on energy metabolism and the impact of chronic PYY3-36 treatment on insulin sensitivity. Mice received a single injection of PYY3-36 or were injected once daily for 7 days, and energy metabolism was subsequently measured in a metabolic cage. Furthermore, the effects of chronic PYY3-36 administration (continuous and intermittent) on glucose turnover were determined during a hyperinsulinemic- euglycemic clamp. PYY3-36 inhibited cumulative food intake for 30 min of refeeding after an overnight fast (0.29 ± 0.04 vs. 0.56 ± 0.12 g, P ± 0.036) in an acute setting, but not after 7 days of daily dosing. Body weight, total energy expenditure, and physical activity were not affected by PYY3-36. However, it significantly decreased the respiratory quotient. Both continuous and intermittent PYY3-36 treatment significantly enhanced insulin-mediated whole body glucose disposal compared with vehicle treatment (81.2 ± 6.2 vs. 77.1 ± 5.2 vs. 63.4 ± 5.5 μmol·min-1·kg-1, respectively). In particular, PYY3-36 treatment increased glucose uptake in adipose tissue, whereas its impact on glucose disposal in muscle did not attain statistical significance. PYY3-36 treatment shifts the balance of fuel use in favor of fatty acids and enhances insulin sensitivity in mice, where it particularly promotes insulin-mediated glucose disposal. Notably, these metabolic effects of PYY3-36 remain unabated after chronic administration, in contrast to its anorexic effects

Oxyntomodulin ameliorates glucose intolerance in mice fed a high-fat diet

We evaluated the acute effects of OXM on glucose metabolism in diet-induced insulin-resistant male C57Bl/6 mice. To determine the effects on glucose tolerance, mice were intraperitoneally injected with OXM (0.75, 2.5, or 7.5 nmol) or vehicle prior to an ip glucose tolerance test. OXM (0.75 nmol/h) or vehicle was infused during a hyperinsulinemic euglycemic clamp to quantify insulin action on glucose production and disposal. OXM dose-dependently improved glucose tolerance as estimated by AUC for glucose (OXM: 7.5 nmol, 1,564 ± 460, P < 0.01; 2.5 nmol, 1,828 ± 684, P < 0.01; 0.75 nmol, 2,322 ± 303, P < 0.05; control: 2,790 ± 222 mmol·l -1·120 min). Insulin levels in response to glucose administration were higher in 7.5 nmol OXM-treated animals compared with controls. In basal clamp conditions, OXM increased EGP (82.2 ± 14.7 vs. 39.9 ± 5.7 μmol·min-1·kg-1, P < 0.001). During insulin infusion, insulin levels were twice as high in OXM-treated mice compared with controls (10.6 ± 2.8 vs. 4.4 ± 2.2 ng/ml, P < 0.01). Consequently, glucose infusion rate (118.6 ± 30.8 vs. 38.8 ± 26.4 μl/h, P < 0.001) and glucose disposal (88.1 ± 13.0 vs. 45.2 ± 6.9 μmol·min -1·kg-1, P < 0.001) were enhanced in mice that received OXM. In addition, glucose production was more suppressed during OXM infusion (35.7 ± 15.5 vs. 15.8 ± 11.4% inhibition, P < 0.05). However, if these data were expressed per unit concentration of circulating insulin, OXM did not affect insulin action on glucose disposal and production. These results indicate that OXM beneficially affects glucose metabolism in diet-induced insulin-resistant C57Bl/6 mice. It ameliorates glucose intolerance, most likely because it elevates glucose-induced plasma insulin concentrations. OXM does not appear to impact on insulin action

Succinate dehydrogenase (SDH)-deficient pancreatic neuroendocrine tumor expands the SDH-related tumor spectrum

Molecular tumour pathology - and tumour genetic

Increased Mortality in SDHB but Not in SDHD Pathogenic Variant Carriers

Contains fulltext : 201148.pdf (publisher's version ) (Open Access

Clinical Aspects of SDHA-Related Pheochromocytoma and Paraganglioma: A Nationwide Study

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