Hypothalamic pituitary dysfunction after nasopharyngeal carcinoma irradiation.

PURPOSE: Radiotherapy (RT) is the corner stone of nasopharyngeal carcinoma (NPC) treatment but it exposes to late effects especially hypothalamic pituitary deficiency (HPD). In this article,we aimed to assess the impact of RT on pituitary function in NPC survivors. METHODS: We included 55 patients treated in the radiation oncology department, of Farhat Hached Hospital in Sousse, Tunisia. RESULTS: All patients received facio-cervical RT with a mean dose of 73.3 Gy to the nasopharynx. After a mean follow up of 9.56 years, 34 patients (61.8%) presented HPD. Associated peripheral involvement was seen in 18.2%. The most prevalent deficiency was of the GH axis in 50.9% followed by secondary adrenal insufficiency in 20%. Panhypopituitarism was noted in 8.8%. The development of HPD wasn't related to RT dose (OR: 0.41(0.05-2.92), p = 0.36) but was significantly associated with male gender (OR: 1.67 (1.21-2.37), p = 0.01). CONCLUSION: HPD post RT is a common phenomenon. Therefore, we recommend regular assessment of pituitary function amongst patients treated with RT for NPC because identification of deficits is crucial to allow early and appropriate hormone replacement therapy in order to improve patients quality of life.

Effect of Constant Illumination on the Function of the Hypothalamic-Pituitary-Adrenal Axis in Nonhuman Primates.

We studied the effect of constant illumination on the effects of administration of arginine vasopressin (AVP), one of the most important regulators of the key adaptive hypothalamic-pituitary-adrenal (HPA) axis under basal conditions and during stress, as well as on the circadian rhythm of activity of HPA axis and the pineal gland in laboratory primates. In young adult female rhesus monkeys exposed to constant illumination for 7 weeks, the rise in the concentration of ACTH and cortisol in response to administration of AVP was markedly reduced in comparison with both the basal period and with the control group of animals. In addition, a destructive effect of constant lighting on circadian rhythm of cortisol secretion was observed in the absence of significant circadian changes in melatonin secretion. The inhibitory effect of constant illumination on the function of the HPA axis under basal conditions and under conditions of its activation can reduce the body's adaptive abilities.

Under-recognized toxicities of cranial irradiation.

Cranial irradiation of primary or metastatic lesions is frequent, historically with 3D-conformal radiation therapy and now with stereotactic radiosurgery and intensity modulation. Evolution of radiotherapy technique is concomitant to systemic treatment evolution permitting long time survival. Thus, physicians have to face underestimated toxicities on long-survivor patients and unknown toxicities from combination of cranial radiotherapy to new therapeutics as targeted therapies and immunotherapies. This article proposes to develop these toxicities, without being exhaustive, to allow a better apprehension of cranial irradiation in current context.

Hypothalamic-Pituitary Axis Dysfunction after Whole Brain Radiotherapy - A Cohort Study.

BACKGROUND/AIM: Hypothalamic-pituitary (HT-P) dysfunction is one of the most common endocrine late effects following cranial radiotherapy. However, there are currently no specific data describing this complication in adult-onset cancer patients after whole brain radiotherapy (WBRT). The present cohort study aims to establish the prevalence of HT-P axis dysfunction in this group of patients. PATIENTS AND METHODS: Twenty-six cancer patients previously treated with WBRT (median follow-up=20.5 months) received standardized endocrine check-up focusing on HT-P function. RESULTS: In 50% of the patients, impaired hypothalamic-pituitary function was detected during follow-up. While functional loss of a single hormonal axis was evident in 34.6% of patients, 7.7% showed an impairment of multiple endocrine axes, and one patient developed adrenocorticotropic hormone deficiency. Hypothalamic-pituitary dysfunction did not directly correlate with the applied WBRT total doses. CONCLUSION: In our cohort, hypothalamic-pituitary dysfunction appeared to be common after WBRT and was diagnosed as early as 6 months following radiation. This finding highlights the need for routine endocrine follow-up even in patients with limited life expectancy.

Undernutrition and Pubertal Timing in Female Survivors of Medulloblastoma and Other Embryonal Tumors.

CONTEXT: Children with brain tumors may have pubertal onset at an inappropriately young chronologic age. Hypothalamic-pituitary irradiation ≥18Gy has been found to be a risk factor; age at irradiation is associated with pubertal timing. However, the underlying mechanisms are unknown. OBJECTIVE: To determine the impact of body mass index (BMI) and catch-up growth on pubertal timing in females treated for medulloblastoma and other embryonal tumors. DESIGN, SETTING, AND PATIENTS: Retrospective cohort analysis of 90 female patients treated for medulloblastoma and other embryonal tumors at Dana-Farber Cancer Institute/Boston Children's Hospital from 1996 to 2016. Eighteen individuals met inclusion criteria, with a mean ± SD follow-up period of 11.9 ± 3.4 years. MAIN OUTCOME MEASURES: Multiple linear regression models for age at pubertal onset and bone age discrepancy from chronologic age at pubertal onset assessed the joint influences of age at irradiation, hypothalamic irradiation dose, undernutrition duration, BMI standard deviation score (SDS) at pubertal onset, and catch-up BMI SDS. RESULTS: The mean ± SD age of pubertal onset was 9.2 ± 1.3 years and hypothalamic radiation dose was 31.9 ± 9.9 Gy. There was a direct relationship between age at irradiation and age at pubertal onset (ß = 0.323 ± 0.144 [standard error] year per year; P = 0.04) that was significantly attenuated after adjusting for BMI SDS at pubertal onset (P = 0.5) and catch-up BMI SDS (P = 0.08), suggesting that BMI is a mediator. CONCLUSIONS: Both absolute and catch-up BMI SDS at pubertal onset are significant mediators of pubertal timing and bone age discrepancy in pediatric medulloblastoma and other embryonal tumors, and thus, are targetable risk factors to optimize pubertal timing.

Microgravity versus Microgravity and Irradiation: Investigating the Change of Neuroendocrine-Immune System and the Antagonistic Effect of Traditional Chinese Medicine Formula.

During spaceflight, the homeostasis of the living body is threatened with cosmic environment including microgravity and irradiation. Traditional Chinese medicine could ameliorate the internal imbalance during spaceflight, but its mechanism is still unclear. In this article, we compared the difference of neuroendocrine-immune balance between simulated microgravity (S) and simulated microgravity and irradiation (SAI) environment. We also observed the antagonistic effect of SAI using a traditional Chinese medicine formula (TCMF). Wistar rats were, respectively, exposed under S using tail suspending and SAI using tail suspending and 60Co-gama irradiation exposure. The SAI rats were intervened with TCMF. The changes of hypothalamic-pituitary-adrenal (HPA) axis, splenic T-cell, celiac macrophages, and related cytokines were observed after 21 days. Compared with the normal group, the hyperfunction of HPA axis and celiac macrophages, as well as the hypofunction of splenic T-cells, was observed in both the S and SAI group. Compared with the S group, the levels of plasmatic corticotropin-releasing hormone (CRH), macrophage activity, and serous interleukin-6 (IL-6) in the SAI group were significantly reduced. The dysfunctional targets were mostly reversed in the TCMF group. Both S and SAI could lead to NEI imbalance. Irradiation could aggravate the negative feedback inhibition of HPA axis and macrophages caused by S. TCMF could ameliorate the NEI dysfunction caused by SAI.

The effect of HF-rTMS over the left DLPFC on stress regulation as measured by cortisol and heart rate variability.

The prefrontal cortex, and especially the Dorsolateral Prefrontal Cortex (DLPFC), plays an inhibitory role in the regulation of the Hypothalamic-Pituitary-Adrenal (HPA) axis under stressful situations. Moreover, recent evidence suggests that a sustained DLPFC activation is associated with adaptive stress regulation in anticipation of a stressful event, leading to a reduced stress-induced amygdala response, and facilitating the confrontation with the stressor. However, studies using experimental manipulation of the activity of the DLPFC before a stressor are scarce, and more research is needed to understand the specific role of this brain area in the stress-induced physiological response. This pre-registered study investigated the effect on stress regulation of a single excitatory high frequency (versus sham) repetitive transcranial magnetic stimulation (HF-rTMS) session over the left DLPFC applied before the Trier Social Stress Test in 75 healthy young women (M = 21.05, SD = 2.60). Heart rate variability (HRV) and salivary cortisol were assessed throughout the experimental protocol. The active HF-rTMS and the sham group showed a similar cognitive appraisal of the stress task. No differences in HRV were observed during both the anticipation and the actual confrontation with the stress task and therefore, our results did not reflect DLPFC-related adaptive anticipatory adjustments. Importantly, participants in the active HF-rTMS group showed a lower cortisol response to stress. The effect of left prefrontal HF-rTMS on the stress system provides further critical experimental evidence for the inhibitory role played by the DLPFC in the regulation of the HPA axis.

Intensity dependent disruptive effects of light at night on activation of the HPG axis of tree sparrows (Passer montanus).

Artificial light at night (ALAN) has become increasingly recognized as a disruptor of the reproductive endocrine process and behavior of wild birds. However, there is no evidence that ALAN directly disrupt the hypothalamus-pituitary-gonadal (HPG) axis, and no information on the effects of different ALAN intensities on birds. We experimentally tested whether ALAN affects reproductive endocrine activation in the HPG axis of birds, and whether this effect is related to the intensity of ALAN, in wild tree sparrows (Passer montanus). Forty-eight adult female birds were randomly assigned to four groups. They were first exposed to a short light photoperiod (8 h light and 16 h dark per day) for 20 days, then exposed to a long light photoperiod (16 h light and 8 h dark per day) to initiate the reproductive endocrine process. During these two kinds of photoperiod treatments, the four groups of birds were exposed to 0, 85, 150, and 300 lux light in the dark phase (night) respectively. The expression of the reproductive endocrine activation related TSH-ß, Dio2 and GnRH-I gene was significantly higher in birds exposed to 85 lux light at night, and significantly lower in birds exposed to 150 and 300 lux, relative to the 0 lux control. The birds exposed to 85 lux had higher peak values of plasma LH and estradiol concentration and reached the peak earlier than birds exposed to 0, 150, or 300 lux did. The lower gene expression of birds exposed to 150 and 300 lux reduced their peak LH and estradiol values, but did not delay the timing of these peaks compared to the control group. These results reveal that low intensity ALAN accelerates the activation of the reproductive endocrine process in the HPG axis, whereas high intensity ALAN retards it.

Hypothalamic-pituitary axis irradiation dose thresholds for the development of hypopituitarism in adult-onset gliomas.

BACKGROUND: Childhood brain tumour survivors who receive cranial radiotherapy undergo regular surveillance for the development ofhypothalamic-pituitary (HP) axis dysfunction. Much less attention has been given to radiation-induced hypopituitarism in patients with malignant brain tumours of adult onset. DESIGN: Retrospective cohort study. PATIENTS/MEASUREMENTS: We assessed the effects of cranial radiotherapy (cXRT) on pituitary function in 58 adults (32 male) with gliomas distant to the HP axis. The XRT dose exposure at the HP axis was correlated with individual axis dysfunction to establish dose thresholds. RESULTS: Mean age at cXRT was 41.2 ± 10.9 years and duration of endocrine follow-up 8.2 ± 5.2 years. Mean XRT dose to the HP axis was 35.9 ± 15.5 Gy. Overall prevalence of radiation-induced hypopituitarism was 84.5%. GH, LH/FSH, ACTH and TSH deficiency were present in 82.8%, 20.7%, 19% and 6.9% of patients, respectively. Hyperprolactinaemia was noted in 10.3% (n = 6) and was persistent in one case. GH deficiency and "any degree of hypopituitarism" positively correlated with the radiotherapy dose to the hypothalamic-pituitary axis. HP axis XRT dose thresholds for the development of GHD, LH/FSH, ACTH and TSH deficiency were established at 10, 30, 32 and 40.8 Gy, respectively. A gradual increase in the prevalence of all anterior pituitary hormone deficits was observed throughout the follow-up period. CONCLUSIONS: Hypopituitarism post-cXRT in adults with gliomas is a frequent, progressive and dose-dependent phenomenon. Dose thresholds suggest long-term endocrine surveillance is important where the HP axis XRT dose is higher than 30 Gy. Identification of deficits to allow early and appropriate hormone replacement therapy is important to improve well-being in these individuals with limited prognosis.

Hypothyroidism after Radiation Therapy for Childhood Cancer: A Report from the Childhood Cancer Survivor Study.

While thyroid cancer risks from exposure to ionizing radiation early in life are well characterized quantitatively, the association of radiation with nonmalignant, functional thyroid disorders has been less studied. Here, we report on a risk analysis study of hypothyroidism with radiation dose to the thyroid gland and the hypothalamic-pituitary axis among survivors of childhood cancer. Utilizing data from the Childhood Cancer Survivor Study, a cohort of 14,364 five-year survivors of childhood cancer diagnosed at 26 hospitals in the U.S. and Canada between 1970 and 1986 and followed through 2009, the occurrence of hypothyroidism was ascertained among 12,015 survivors through serial questionnaires. Radiation doses to the thyroid gland and pituitary gland were estimated from radiotherapy records. Binary outcome regression was used to estimate prevalence odds ratios for hypothyroidism at five years from diagnosis of childhood cancer and Poisson regression to model incidence rate ratios (RR) after the first five years. A total of 1,193 cases of hypothyroidism were observed, 777 (65%) of which occurred five or more years after cancer diagnosis. The cumulative proportion affected with hypothyroidism (prevalence at five years after cancer diagnosis plus incidence through 30 years after cancer diagnosis) was highest among five-year survivors of Hodgkin lymphoma (32.3%; 95% CI: 29.5-34.9) and cancers of the central nervous system (17.7%; 95% CI: 15.2-20.4). The incidence rate was significantly associated with radiation dose to the thyroid and pituitary. The joint association of hypothyroidism with thyroid and pituitary dose was sub-additive for pituitary doses greater than 16 Gy. In particular, a very strong thyroid radiation dose dependence at low-to-moderate pituitary/hypothalamic doses was diminished at high pituitary doses. Radiation-related risks were higher in males than females and inversely associated with age at exposure and time since exposure but remained elevated more than 25 years after exposure. Our findings indicated that hypothyroidism was significantly associated with treatment with bleomycin (RR = 3.4; 95% CI: 1.6-7.3) and the alkylating agents cyclohexyl-chloroethyl-nitrosourea (CCNU) (RR = 3.0; 95% CI: 1.5-5.3) and cyclophosphamide (RR = 1.3; 95% CI: 1.0-1.8), with a significant dose response for CCNU ( P < 0.01). The risk of hypothyroidism among childhood cancer survivors treated with radiation depends both on direct, dose-dependent radiation-induced damage to the thyroid gland and on dose-dependent indirect effects secondary to irradiation of the hypothalamic-pituitary axis. The dose-response relationship for each site depends on dose to the other. Radiation-related risk persists for more than 25 years after treatment. Treatment with certain chemotherapy agents may increase the risk of hypothyroidism.

Skin Exposure to Ultraviolet B Rapidly Activates Systemic Neuroendocrine and Immunosuppressive Responses.

The back skin of C57BL/6 mice was exposed to a single 400 mJ cm-2 dose of ultraviolet B (UVB), and parameters of hypothalamic-pituitary-adrenal (HPA) axis in relation to immune activity were tested after 30-90 min following irradiation. Levels of brain and/or plasma corticotropin-releasing hormone (CRH), ß-endorphin, ACTH and corticosterone (CORT) were enhanced by UVB. Hypophysectomy had no effect on UVB-induced increases of CORT. Mitogen-induced IFNγ production by splenocytes from UVB-treated mice was inhibited at 30, 90 min and after 24 h. UVB also led to inhibition of IL-10 production indicating an immunosuppressive effect on both Th1 and Th2 cytokines. Conditioned media from splenocytes isolated from UVB-treated animals had no effect on IFNγ production in cultured normal splenocytes; however, IFNγ increased with conditioned media from sham-irradiated animals. Sera from UVB-treated mice suppressed T-cell mitogen-induced IFNγ production as compared to sera from sham-treated mice. IFNγ production was inhibited in splenocytes isolated from UVB-treated animals with intact pituitary, while stimulated in splenocytes from UVB-treated hypophysectomized mice. Thus, cutaneous exposure to UVB rapidly stimulates systemic CRH, ACTH, ß-endorphin and CORT production accompanied by rapid immunosuppressive effects in splenocytes that appear to be independent of the HPA axis.

Time Dependence of Radiation-induced Hypothalamic-Pituitary Axis Dysfunction in Adults Treated for Non-pituitary, Intracranial Neoplasms.

AIMS: Hypothalamic-pituitary axis (HPA) dysfunction is a sequela of cranial radiotherapy. The purpose of this study was to use endocrine data from existing publications to characterise the baseline endocrine status, the effects of radiotherapy on the HPA during the first follow-up year and the time dependence of radiation-induced HPA dysfunction in patients treated with radiotherapy for non-pituitary intracranial neoplasms. MATERIALS AND METHODS: A systematic search of databases was carried out for articles that reported the results of endocrine testing for patients aged 16 years and older who were treated with neurosurgery for non-pituitary intracranial neoplasms or radiotherapy for nasopharyngeal neoplasms. To analyse the radiotherapy-related changes in hormone levels over time, long-term prospective endocrine data from nasopharyngeal studies were normalised to baseline hormone data and fitted to an exponential decay model. This process was repeated with normalisation to year 1 hormone data. RESULTS: Eight unique articles met eligibility criteria. HPA dysfunction occurred in 21.6-64.7% of patients who were assessed for endocrinopathies following neurosurgery. Studies on the early effects of radiotherapy on nasopharyngeal patients showed statistically significant changes in growth hormone, luteinizing hormone and follicle stimulating hormone levels during the first year of follow-up. Time dependence modelling showed that normalisation to year 1 hormone levels yield exponential equations with stronger measures of goodness of fit. CONCLUSION: HPA dysfunction in patients treated for non-pituitary intracranial neoplasms is probably a result of both neurosurgery and radiotherapy treatments. Although statistically significant endocrine changes can occur during this first year of follow-up, those documented at year 1 may be more predictive of subsequent HPA dysfunction.

A short-term extremely low frequency electromagnetic field exposure increases circulating leukocyte numbers and affects HPA-axis signaling in mice.

There is still uncertainty whether extremely low frequency electromagnetic fields (ELF-EMF) can induce health effects like immunomodulation. Despite evidence obtained in vitro, an unambiguous association has not yet been established in vivo. Here, mice were exposed to ELF-EMF for 1, 4, and 24 h/day in a short-term (1 week) and long-term (15 weeks) set-up to investigate whole body effects on the level of stress regulation and immune response. ELF-EMF signal contained multiple frequencies (20-5000 Hz) and a magnetic flux density of 10 µT. After exposure, blood was analyzed for leukocyte numbers (short-term and long-term) and adrenocorticotropic hormone concentration (short-term only). Furthermore, in the short-term experiment, stress-related parameters, corticotropin-releasing hormone, proopiomelanocortin (POMC) and CYP11A1 gene-expression, respectively, were determined in the hypothalamic paraventricular nucleus, pituitary, and adrenal glands. In the short-term but not long-term experiment, leukocyte counts were significantly higher in the 24 h-exposed group compared with controls, mainly represented by increased neutrophils and CD4 ± lymphocytes. POMC expression and plasma adrenocorticotropic hormone were significantly lower compared with unexposed control mice. In conclusion, short-term ELF-EMF exposure may affect hypothalamic-pituitary-adrenal axis activation in mice. Changes in stress hormone release may explain changes in circulating leukocyte numbers and composition. Bioelectromagnetics. 37:433-443, 2016. © 2016 The Authors. Bioelectromagnetics Published by Wiley Periodicals, Inc.

[Effect of Qidan Granule on PMC Derived Peptide Content and Structure of Hippocampal CA1 Region in Microwave Radiated Rats].

OBJECTIVE: To explore the protection of high intensity microwave radiation on hypothalamo-pituitary-adrenal axis (HPAA) activity and hippocampal CA1 structure in rats and the protectiveeffect of Qindan Granule (QG) on radiation injured rats. METHODS: Totally 48 Wistar rats were randomlydivided into 8 groups, i.e., the normal control group, post-radiation day 1, 7, and 10 groups, 7 and 10days prevention groups, day 7 and 10 treatment groups, 6 in each group. Rats in prevention groups wererespectively administered with QG liquid (1 mL/100 g, 4. 75 g crude drugs) for 7 days and 10 days bygastrogavage and then microwave radiation. Then preventive effect for radiation injury was statisticallycalculated with the normal control group and the post-radiation day 1 group. Rats in treatment groupswere firstly irradiated, and then administered with QG liquid (1 mL/100 g, 4.75 g crude drugs). Finally preventive effect for radiation injury was statistically calculated with the normal control group, post-radiation day 7 and 10 groups. Contents of corticotrophin releasing hormone (CRH), beta endorphin (beta-EP), adrenocorticotropic hormone (ACTH), and heat shock protein 70 (HSP70) were detected. Morphological changes and structure of hippocampal CA1 region were observed under light microscope. RESULTS: Compared with the normal control group, contents of CRH and beta-EP significantly decreased in each radiation group. Serum contents of ACTH and beta-EP significantly increased in post-radiation day 1 and 7 groups (P < 0.05). Compared with radiation groups, beta-EP content in serum and pituitary significantly increased, and serum ACTH content significantly decreased in prevention groups (P < 0.05). Pituitary contents of CRH and beta-EP significantly increased in prevention groups. Serum contents of ACTH, beta-EP, and HSP70 were significantly lower in day 7 treatment group than post-radiation day 7 group (P < 0.05). Morphological results showed that pyramidal neurons in the hippocampal CA1 region arranged in disorder, with swollen cells, shrunken and condensed nucleus, dark dyeing cytoplasm, unclear structure. Vessels in partial regions were dilated with static blood; tissues were swollen and sparse. In prevention and treatment groups pathological damage of hippocampal CA1 region was obviously attenuated; neurons were arranged more regularly; swollen, pycnotic, or deleted neuron number were decreased; vascular dilatation and congestion was lessened. CONCLUSION: QG could affect HPAA function and activity of high intensity microwave radiated rats, showing certain preventive and therapeutic effects of microwave radiated rats by adjusting synthesis and release of partial bioactive peptides and hormones in HPAA, improving pathological injury in hippocampal CA1 region.

[LED LIGHTING AS A FACTOR FOR THE STIMULATION OF THE HORMONE SYSTEM].

There are considered questions of non-visual effects of blue LED light sources on hormonal systems (cortisol, glucose, insulin) providing the high human performance. In modern conditions hygiene strategy for child and adolescent health strategy was shown to be replaced by a strategy of light stimulation of the hormonal profile. There was performed a systematic analysis of the axis "light stimulus-hypothalamus-pituitary-adrenals-cortisol-glucose-insulin". The elevation of the content of cortisol leads to the increase of the glucose level in the blood and the stimulation of the production of insulin, which can, like excessive consumption of food, give rise to irreversible decline in the number of insulin receptors on the cell surface, and thus--to a steady reduction in the ability of cells to utilize glucose, i.e. to type 2 diabetes or its aggravation.

Light therapy for better mood and insulin sensitivity in patients with major depression and type 2 diabetes: a randomised, double-blind, parallel-arm trial.

BACKGROUND: Major depression and type 2 diabetes often co-occur. Novel treatment strategies for depression in type 2 diabetes patients are warranted, as depression in type 2 diabetes patients is associated with poor prognosis and treatment results. Major depression and concurrent sleep disorders have been related to disturbances of the biological clock. The biological clock is also involved in regulation of glucose metabolism by modulating peripheral insulin sensitivity. Light therapy has been shown to be an effective antidepressant that 'resets' the biological clock. We here describe the protocol of a study that evaluates the hypothesis that light therapy improves mood as well as insulin sensitivity in patients with a major depressive episode and type 2 diabetes. METHODS/DESIGN: This study is a randomised, double-blind, parallel-arm trial in 98 participants with type 2 diabetes and a major depressive episode, according to DSM-IV criteria. We will assess whether light therapy improves depressive symptoms and insulin sensitivity, our primary outcome measures, and additionally investigate whether these effects are mediated by restoration of the circadian rhythmicity, as measured by sleep and hypothalamic-pituitary-adrenal axis activity. Participants will be randomly allocated to a bright white-yellowish light condition or dim green light condition. Participants will undergo light therapy for half an hour every morning for 4 weeks at home. At several time points, namely before the start of light therapy, during light therapy, after completion of 4 weeks of light therapy and after 4 weeks follow-up, several psychometrical, psychophysiological and glucometabolic measures will be performed. DISCUSSION: If light therapy effectively improves mood and insulin sensitivity in type 2 diabetes patients with a major depressive episode, light therapy may be a valuable patient friendly addition to the currently available treatment strategies. Additionally, if our data support the role of restoration of circadian rhythmicity, such an observation may guide further development of chronobiological treatment strategies in this patient population. TRIAL REGISTRATION: The Netherlands Trial Register (NTR) NTR4942 . Registered 13 January 2015.

Cellular signaling protective against noise-induced hearing loss ­ A role for novel intrinsic cochlear signaling involving corticotropin-releasing factor?

Hearing loss afflicts approximately 15% of the world's population, and crosses all socioeconomic boundaries. While great strides have been made in understanding the genetic components of syndromic and non-syndromic hearing loss, understanding of the mechanisms underlying noise-induced hearing loss (NIHL) have come much more slowly. NIHL is not simply a mechanism by which older individuals loose their hearing. Significantly, the incidence of NIHL is increasing, and is now involving ever younger populations. This may predict future increased occurrences of hearing loss. Current research has shown that even short-term exposures to loud sounds generating what was previously considered temporary hearing loss, actually produces an almost immediate and permanent loss of specific populations of auditory nerve fibers. Additionally, recurrent exposures to intense sound may hasten age-related hearing loss. While NIHL is a significant medical concern, to date, few compounds have delivered significant protection, arguing that new targets need to be identified. In this commentary, we will explore cellular signaling processes taking place in the cochlea believed to be involved in protection against hearing loss, and highlight new data suggestive of novel signaling not previously recognized as occurring in the cochlea, that is perhaps protective of hearing. This includes a recently described local hypothalamic-pituitary-adrenal axis (HPA)-like signaling system fully contained in the cochlea. This system may represent a local cellular stress-response system based on stress hormone release similar to the systemic HPA axis. Its discovery may hold hope for new drug therapies that can be delivered directly to the cochlea, circumventing systemic side effects.

Skin under the (Spot)-Light: Cross-Talk with the Central Hypothalamic-Pituitary-Adrenal (HPA) Axis.

UV radiation is among the most prevalent stressors in humans and diurnal rodents, exerting direct and indirect DNA damage, free-radical production, and interaction with specific chromophores that affects numerous biological processes. In addition to its panoply of effects, UVB (290-320 nm) radiation can specifically affect various local neuroendocrine activities by stimulating the expression of corticotropin-releasing hormone (CRH), urocortin, proopiomelanocortin (POMC), and POMC-derived peptides. Although very little is known about the interplay between the central hypothalamic-pituitary-adrenal (HPA) axis and the skin HPA axis analog, in the current issue Skobowiat and Slominski propose a novel mechanism by which exposure to UVB activates a local HPA axis in skin, which in turn activates the central HPA axis, with the requirement of a functional pituitary gland. This is the first evidence of the local HPA axis in skin contributing to the central neuroendocrine response. This raises intriguing possibilities regarding how local production of cortisol and other HPA axis molecules in skin influence overall systemic levels of cortisol and help regulate local and central HPA axes in the context of homeostasis, skin injury, and inflammatory skin disorders.

[Impact of radiotherapy on female fertility]. / Impact de la radiothérapie sur la fertilité féminine.

Radiation therapy may have deleterious effects on female fertility. It can cause ovarian dysfunction, uterine damages or disrupt the hypothalamic-pituitary axis. These effects occur at varying dose levels usually relatively low compared to the prescribed doses. Other co-factors influence the effects of radiation therapy on fertility, such as age or therapy with alkylating agents. This review aims to make an update on the current state of knowledge about the impact of radiotherapy on female fertility.

[Endocrine sequelae after treatment of pediatric cancer: From childhood to adulthood]. / Séquelles endocriniennes après traitement d'un cancer pédiatrique : de l'enfance à l'âge adulte.

Endocrine sequelae are among the most frequently reported complications in childhood cancer survivors, affecting 40 to 60% of these patients during adult life. Most of these complications are the result of cranial radiation therapy for brain or facial tumor, lymphoma or leukemia. The present review describes the main endocrine disturbances observed in this population, including disorders of hypothalamic-pituitary axis, especially the frequently observed growth hormone deficiency and disorders of puberty, thyroid and parathyroid dysfunction, obesity and metabolic syndrome, alterations in glucose metabolism and decreased bone mineral density. Gonadal dysfunction is not described, since it is detailed in another chapter. During childhood, prompt diagnosis and management of endocrine complications allow improvement of final height outcome and body composition (lean body mass and bone mass), reducing morbidity and impaired quality of life later in adulthood. Risk of developing a second neoplasm after growth hormone therapy in cancer survivors is also addressed. Life-long follow-up and management of endocrine deficiencies are essential to reduce late morbidity especially cardiovascular risk, and to diagnose late-onset deficiencies as well as radiation-induced thyroid nodules and cancer.