Journal of Neuroendocrinology最新文献

In aging women, cognitive decline and increased risk of dementia have been associated with the cessation of ovarian hormones production at menopause. In the brain, presence of the key enzyme aromatase required for the synthesis of 17-β-estradiol (E2) allows for local production of E2 in absence of functional ovaries. Understanding how aromatase activity is regulated could help alleviate the cognitive symptoms. In female rodents, genetic or pharmacological reduction of aromatase activity over extended periods of time impair memory formation, decreases spine density, and hinders long-term potentiation (LTP) in the hippocampus. Conversely, increased excitatory neurotransmission resulting in rapid N-methyl-d-aspartic acid (NMDA) receptor activation rapidly promotes neuroestrogen synthesis. This rapid modulation of aromatase activity led us to address the hypothesis that acute neuroestrogens synthesis is necessary for LTP at the Schaffer collateral-cornu ammonis 1 (CA1) synapse in absence of circulating ovarian estrogens. To test this hypothesis, we did electrophysiological recordings of field excitatory postsynaptic potential (fEPSPs) in hippocampal slices obtained from ovariectomized mice. To assess the impact of neuroestrogens synthesis on LTP, we applied the specific aromatase inhibitor, letrozole, before the induction of LTP with a theta burst stimulation protocol. We found that blocking aromatase activity prevented LTP. Interestingly, exogenous E2 application, while blocking aromatase activity, was not sufficient to recover LTP in our model. Our results indicate the critical importance of rapid, activity-dependent local neuroestrogens synthesis, independent of circulating hormones for hippocampal synaptic plasticity in female rodents.

The naked mole-rat (Heterocephalus glaber) is a unique model mammal in which to study socially induced inhibition of the hypothalamic–pituitary–gonadal (HPG) axis. Naked mole-rat groups exhibit a high degree of reproductive bias in which breeding is restricted to one female (the queen) and one male, with subordinate non-breeding colony members rarely, if ever, having the opportunity to reproduce due to a dysfunctional HPG axis. It is posited that aggression directed at subordinates by the queen suppresses reproduction in these subordinates, yet the underlying physiological mechanisms causing this dysfunction are unknown. This study aimed to investigate the possible factors contributing to the dysfunction of the HPG axis in subordinate female naked mole-rats with a specific focus on the role of ovarian feedback and stress-related factors such as circulating glucocorticoid and endogenous opioid peptides. The results showed that stress-related factors appear to not mediate the suppression of reproductive function in subordinate female naked mole rats. Indeed, in some cases, the activation of the stress axis may lead to reproductive activation instead of deactivation. At the same time, the role of ovarian sex steroid feedback in reproductive suppression is likely limited and not clearly delineated. This study highlights the need for detailed studies to elucidate the mechanism of reproductive suppression in this unique model mammalian species which may shed light on, and reveal novel mechanisms, in the social regulation of reproduction.

Pubertal timing is a highly heritable trait in the general population. Recently, a large-scale exome-wide association study has implicated rare variants in six genes (KDM4C, MC3R, MKRN3, PDE10A, TACR3, and ZNF483) as genetic determinants of pubertal timing within the general population. Two of the genes (TACR3, MKRN3) are already implicated in extreme disorders of pubertal timing. This observation suggests that there may be a pervasive “genetic risk continuum” wherein genes that govern pubertal timing in the general population, by extension, may also be causal for rare Mendelian disorders of pubertal timing. Hence, we hypothesized that the four novel genes linked to pubertal timing in the population will also contribute to idiopathic hypogonadotropic hypogonadism (IHH), a genetic disorder characterized by absent puberty. Exome sequencing data from 1322 unrelated IHH probands were reviewed for rare sequence variants (RSVs) (minor allele frequency bins: <1%; <0.1%; <0.01%) in the six genes linked to puberty in the general population. A gene-based rare variant association testing (RVAT) was performed between the IHH cohort and a reference public genomic sequences repository—the Genome Aggregation Database (gnomAD). As expected, RVAT analysis showed that RSVs in TACR3, a known IHH gene, were significantly enriched in the IHH cohort compared to gnomAD cohort across all three MAF bins. However, RVAT analysis of the remaining five genes failed to show any RSV enrichment in the IHH cohort across all MAF bins. Our findings argue strongly against a pervasive genetic risk continuum between pubertal timing in the general population and extreme pubertal phenotypes. The biologic basis of such distinct genetic architectures' merits further evaluation.

Peptide receptor radionuclide therapy (PRRT) has been primarily studied in low and intermediate-grade digestive neuroendocrine tumors (NET G1-G2). The documentation of a similar benefit for high-grade digestive neuroendocrine neoplasms (NEN) has been limited. This review evaluates the use of PRRT for high-grade digestive NEN (well-differentiated NET G3 and poorly differentiated neuroendocrine carcinomas [NEC]). We identified one phase III trial and seven retrospective studies reporting specifically on PRRT outcome of >10 digestive high-grade NEN patients. The retrospective single-arm studies indicate a benefit for PRRT in NET G3. The randomized phase III NETTER-2 trial demonstrates major PFS superiority of PRRT versus somatostatin analog therapy as the first-line treatment for the NET G3 subgroup. PRRT can now be considered a potential first-line treatment for somatostatin receptor-positive NET G3 patients, but whether it should be the first-line standard of care for all NET G3 patients is still not clarified. For NEC, scarce data are available, and pathologic distinction between NEC and NET G3 can be difficult when Ki-67 is below 55%. PRRT could be considered as a treatment for refractory NEC in very selected cases when there is a high uptake on somatostatin receptor imaging, Ki-67 is below 55%, and there is no rapid tumor progression.

Few studies have been published on the long-term outcomes of patients with gastric neuroendocrine tumors (gNETs). We analyzed their management over a two-decade period, focusing on endoscopic and clinical outcomes. Clinical, laboratory, endoscopic, surgical, and histopathological data from Types 1 and 3 gNETs histologically diagnosed between March 2000 and December 2021 at the European Institute of Oncology (IEO, Milan) were retrospectively collected. Sixty-nine patients were included (60 Type 1, 9 Type 3): 53 (77%) were treated endoscopically, 6 (9%) surgically, and 10 (14%) did not receive any treatment. Overall, 293 lesions were removed endoscopically: 74% by forceps, 20% by endoscopic mucosal resection (EMR), and 5% by endoscopic submucosal dissection (ESD). No differences were observed between EMR and ESD in terms of complete resection rate (p value = .50) and complications rate (p value = .084). The median follow-up period was 5.8 years (range: 0.3-20.5), during which no gNET-related deaths were observed. Metachronous gNETs developed in 60% of patients with Type 1 gNET. Six patients with lymph node metastases (LNM) were younger (p value = .006) and had larger lesions (p value <.001) than patients without LNM. Most Type 1 gNETs were successfully excised using forceps, with EMR and ESD being equally effective. The presence of incomplete resection was not associated with a worse prognosis, which remains excellent in this highly recurrent disease. Younger age and a size ≥10 mm were associated with an increased risk of LNM. CLINICAL TRIAL REGISTRATION: Project code UID 2854.

Hypothalamic obesity (HO) is defined as abnormal weight gain resulting in severe persistent obesity due to physical, tumor- and/or treatment-related damage to the hypothalamus. HO epidemiology is poorly understood. We developed a database algorithm supporting the standardized identification of tumor/treatment-related HO (TTR-HO) patients. The algorithm is used to estimate incidence rates of TTR-HO patients in the German healthcare context from a representative claims database (n = 5.42 million) covering 2010-2020. Patients were identified based on surgery/radiotherapy procedures and HO-associated tumor diagnoses (n = 3976). HO was defined by incident obesity and validated based on incident diabetes insipidus diagnoses and desmopressin prescription within a 12-month period after surgery/radiotherapy. Uncertainty due to algorithm definitions is explored in sensitivity analyses. Estimated annual incidence of TTR-HO in Germany is between 0.7 and 1.7 cases per 1,000,000 persons (2019 prevalence: n = 1262 patients). With observed cases in all age groups, two HO-incidence peaks are identified: children/young adults aged 10-24 years and adults aged 40-44 years. Most frequent HO-validated tumor diagnoses are benign sellar/suprasellar tumors (6.1/1,000,000 persons over 9 years), including tumors of the craniopharyngeal duct (1.3/1,000,000), neoplasms of the pituitary gland (4.1/1,000,000), and nonspecific brain tumors of endocrine glands (2.4/1,000,000). This is the first real-world database analysis of TTR-HO epidemiology, refining current estimates of HO epidemiology and early patient identification. A more comprehensive characterization of patients with HO as well as a better understanding of clinical implications will be crucial in developing optimal treatment strategies to improve patient outcomes.