Epigenetics of functional hypothalamic amenorrhea

Functional hypothalamic amenorrhea (FHA) is a temporary infertility characterized by the suppression of the hypothalamic-pituitary-gonadal (HPG) axis, induced by the inhibition of the hypothalamic pulsatile secretion of the gonadotropin-releasing hormone (GnRH), in the presence of stressors, including eating disorders, excessive exercise, and psychological distress. Although the stressful factors that may lead to FHA are well-established, little is known about the inter-individual variability in response to stress and the consequent inhibition of the HPG axis. Not all women, indeed, manifest FHA in presence of stressful conditions. Recent studies highlighted a genetic contribution to FHA. Rare or polymorphic variants in genes that control the development and/or function of GnRH neurons may contribute, indeed, to the adaptability of the reproductive axis to stress factors. Also epigenetic changes have been associated with different pathways involved in the HPG axis and therefore, take part in FHA and confer a personal predisposition to anovulation consequent to a stressful event, or represent biological markers of response to stress. This review summarizes recent advances in the identification of the contribution of (epi)genetics to FHA and to long-term complications of functional amenorrhea, and reports insights into the involvement of additional genetic loci in FHA development on the bases of the clinical and molecular overlap with other gynecological and/or psychological conditions. Finally, we describe the promising application of induced pluripotent stem cells (iPSCs) as a new approach to investigate the molecular pathways involved in FHA.

Determinants of outcome of transsphenoidal surgery for Cushing disease in a single-centre series

BACKGROUND

First-line therapy of Cushing disease (CD) is transsphenoidal surgery (TSS) aimed to obtain a complete removal of the pituitary adenoma and remission of disease.

PURPOSE

To analyse the surgical outcome of patients with CD who underwent TSS in our Centre.

METHODS

Retrospective analysis on patients with CD who underwent TSS between 1990 and 2016.

RESULTS

We analysed 102 TSS that included: 84 first TSS and 18 second and third TSS. The overall remission rate after surgery was 76.5%, with a significant higher percentage of remitted patients after the first TSS compared to the subsequent TSS (82% vs 50%, p = 0.014). The remission after the first TSS was significantly higher when performed by a dedicated surgical team (DST) (89.8% vs 71% p = 0.04) and when the immunohistochemical examination confirmed the adrenocorticotropic adenoma (87% vs 55%, p = 0.04). Neuroradiological findings influenced the surgical outcome in a non-significant manner. Post-TSS complications were reported in 32 patients, with no significant variation when TSS was performed by DST. In case of reintervention, remission of disease was obtained in 72.7% of microadenoma, while no remitted patients were observed in case of macroadenomas. The DST did not significantly improve the outcome.

CONCLUSION

Cushing disease is characterized by a broad spectrum of neuroradiological presentation. Despite the availability of a DST make the TSS a safe and effective first-line treatment among all these patients, a precise pre-treatment evaluation is needed in order to define the aim of neurosurgery and to schedule the management of recurrent disease.

Mechanical loading of intervertebral disc modulates microglia proliferation, activation, and chemotaxis

OBJECTIVE

The aim of the study is to assess the effects of the neuroinflammatory microenvironment of a mechanically-induced degenerating intervertebral disc (IVD) on neuroinflammatory like cells such as microglia, in order to comprehend the role of microglial cells in degenerative disc disease.

METHODS

Bovine caudal IVDs were kept in culture in an ex vivo bioreactor under high frequency loading and limited nutrition or in free swelling conditions as control samples. Conditioned media (CM) were collected, analysed for cytokine and neurotrophin content and applied to microglial cells for neuroinflammatory activation assessment.

RESULTS

Degenerative conditioned medium (D-CM) induced a higher production of interleukin (IL)-8, nerve growth factor (NGF), interferon (IFN)-γ, IL-17 from IVD cells than unloaded control conditioned medium (U-CM). Upon 48 h of co-incubation with microglia, D-CM stimulated microglia proliferation, activation, with increased expression of ionized calcium binding adaptor molecule 1 (IBA1) and CD68, and chemotaxis. Moreover, an increment of nitrite production was observed. Interestingly, D-CM caused an upregulation of IL-1β, IL-6, tumour necrosis factor α (TNFα), inducible NO synthase (iNOS), IBA1, and vascular endothelial growth factor (VEGF) genes in microglia. Similar results were obtained when microglia were treated with the combination of the measured cytokines.

CONCLUSIONS

Our findings show that in IVD degenerative microenvironment, IL-8, NGF, IFN-γ, IL-17 drive activation of microglia in the spinal cord and increase upregulation of neuroinflammatory markers. This, in turn, enhances the inflammatory milieu within IVD tissues and in the peridiscal space, aggravating the cascade of degenerative events. This study provides evidence for an important role of microglia in maintaining IVD neuroinflammatory microenvironment and probably inducing low back pain.

Acute spinal cord injury reduces brain derived neurotrohic factor expression in rat hippocampus

Spinal cord injury (SCI) is a devastating event which causes dramatic changes in the everyday life of the patient. We have found that acute SCI reduced BDNF expression selectively in the hippocampus of lesioned rats, a decrease which persists at least 1 week, thus identifying the modulation of the neurotrophin biosynthesis as an important mechanism underlying brain vulnerability to SCI. These data are the first to show that SCI alters hippocampal BDNF expression and identify the neurotrophin as a potential target through which SCI changes brain functions, a notion that might prove useful in understanding the mechanisms underlying brain vulnerability to SCI.