Compression of the optic chiasm is associated with permanent shorter sleep duration in patients with pituitary insufficiency

Sleep quality in patients with non-functioning pituitary adenoma: impact of replacement therapies with an emphasis on the time of hydrocortisone

PURPOSE

Sleep disturbances are widespread and associated with pituitary diseases, even those under long-term therapeutic management. The aim of this study was to investigate sleep quality in patients with non-functioning pituitary adenoma (NFPA) and determine the factors that might influence sleep quality, including the detailed features of replacement therapy.

METHODS

Eighty-two patients with NFPA and 82 age- and gender-matched control subjects were included. Pittsburgh Sleep Quality Index (PSQI), Hospital Anxiety and Depression Scale (HADS) and International Physical Activity Questionnaire (IPAQ) were used.

RESULTS

In the NFPA group, 57.3% of patients had decreased sleep quality, compared to 35.4% in the control group (p=0.005). Although there was no relationship between the presence of hydrocortisone replacement and sleep quality (p>0.05), a strong positive correlation was observed between PSQI and morning hydrocortisone replacement time in patients with secondary adrenal insufficiency (r=0.834, p<0.001). Diabetes insipidus was found to be significantly higher in the group with decreased sleep quality (p=0.01). Moreover, there was a negative correlation between PSQI and IGF-1 in patients with NFPA (r=-0.259, p=0.01). A multivariate logistic regression model revealed that depression score and free T4 level in the upper half of the normal limit influence the sleep quality of patients with NFPA.

CONCLUSION

Our study indicated the presence of depression, and a free T4 level in the upper half of the normal range have an impact on the sleep quality of patients with NFPA. The time of hydrocortisone replacement might be important factor for improved sleep quality in patients with secondary adrenal insufficiency.

Compression of the optic chiasm is associated with reduced photoentrainment of the central biological clock

OBJECTIVE

Pituitary tumours that compress the optic chiasm are associated with long-term alterations in sleep-wake rhythm. This may result from damage to intrinsically photosensitive retinal ganglion cells (ipRGCs) projecting from the retina to the hypothalamic suprachiasmatic nucleus via the optic chiasm to ensure photoentrainment (i.e. synchronisation to the 24-h solar cycle through light). To test this hypothesis, we compared the post-illumination pupil response (PIPR), a direct indicator of ipRGC function, between hypopituitarism patients with and without a history of optic chiasm compression.

DESIGN

Observational study, comparing two predefined groups.

METHODS

We studied 49 patients with adequately substituted hypopituitarism: 25 patients with previous optic chiasm compression causing visual disturbances (CC+ group) and 24 patients without (CC- group). The PIPR was assessed by chromatic pupillometry and expressed as the relative change between baseline and post-blue-light stimulus pupil diameter. Objective and subjective sleep parameters were obtained using polysomnography, actigraphy, and questionnaires.

RESULTS

Post-blue-light stimulus pupillary constriction was less sustained in CC+ patients compared with CC- patients, resulting in a significantly smaller extended PIPR (mean difference: 8.1%, 95% CI: 2.2-13.9%, P = 0.008, Cohen's d = 0.78). Sleep-wake timing was consistently later in CC+ patients, without differences in sleep duration, efficiency, or other rest-activity rhythm features. Subjective sleep did not differ between groups.

CONCLUSION

Previous optic chiasm compression due to a pituitary tumour in patients with hypopituitarism is associated with an attenuated PIPR and delayed sleep timing. Together, these data suggest that ipRGC function and consequently photoentrainment of the central biological clock is impaired in patients with a history of optic chiasm compression.

Quality of Life and Sleep in Patients with Pituitary Adenoma in Relation to Tumor Type and Compression of the Optic Chiasm

Objective: To determine the effect of transsphenoidal surgery on quality of life and sleep in patients with pituitary adenomas depending on tumor type and compression of the optic chiasm. Methods: In this prospective study, patients with pituitary adenomas who were scheduled for transsphenoidal surgery completed the Short Form 36 Questionnaire, Pittsburgh Sleep Quality Index, and Epworth Sleepiness Scale preoperatively and 7.5 (±1.5) months after surgery. Patients were analyzed based on tumor type and compression of the optic chiasm. Results: Significant improvements with large effect sizes were seen for patients with Cushing’s disease in general health (Z = −2.37; p = 0.018), vitality (Z = −2.05; p = 0.041), and mental health (Z = −2.06; p = 0.040). A significant deterioration with large effect size occurred in physical functioning (Z = −2.02; p = 0.043) in patients with acromegaly. A significant improvement with medium effect size was seen in subjective sleep quality, (Z = −2.24; p = 0.025), sleep duration (Z = −2.11; p = 0.035), and habitual sleep efficiency (Z = −2.26; p = 0.024) after decompression of the optic chiasm. Multiple significant correlations were observed between sleep parameters and Short Form 36 subscales before and after treatment. Conclusions: Changes in quality of life during the follow-up period depend on tumor type. Circadian rhythm disturbances may resolve promptly after decompression of the optic chiasm. Quality of life in pituitary adenoma patients is associated with quality of sleep in many dimensions, thus implying that developing strategies to improve sleep quality could increase overall well-being and everyday functioning in pituitary adenoma patients.

The Mammalian Circadian Timing System and the Suprachiasmatic Nucleus as Its Pacemaker

The past twenty years have witnessed the most remarkable breakthroughs in our understanding of the molecular and cellular mechanisms that underpin circadian (approximately one day) time-keeping. Across model organisms in diverse taxa: cyanobacteria (Synechococcus), fungi (Neurospora), higher plants (Arabidopsis), insects (Drosophila) and mammals (mouse and humans), a common mechanistic motif of delayed negative feedback has emerged as the Deus ex machina for the cellular definition of ca. 24 h cycles. This review will consider, briefly, comparative circadian clock biology and will then focus on the mammalian circadian system, considering its molecular genetic basis, the properties of the suprachiasmatic nucleus (SCN) as the principal circadian clock in mammals and its role in synchronising a distributed peripheral circadian clock network. Finally, it will consider new directions in analysing the cell-autonomous and circuit-level SCN clockwork and will highlight the surprising discovery of a central role for SCN astrocytes as well as SCN neurons in controlling circadian behaviour.

Altered sleep patterns in patients with non-functional GHRH receptor

OBJECTIVES

GH-releasing hormone (GHRH) exerts hypnotic actions increasing the non-rapid eye movement (NREM) sleep. Conversely, GH stimulates the REM sleep. GH deficiency (GHD) often leads to sleep problems, daytime fatigue and reduced quality of life (QoL). GHD may be due to lack of hypothalamic GHRH or destruction of somatotroph cells. We have described a cohort with isolated GHD (IGHD) due to GHRH resistance caused by a homozygous null mutation (c.57 + 1G > A) in the GHRH receptor gene. They have normal QoL and no obvious complaints of chronic tiredness. The aim of this study was to determine the sleep quality in these subjects.

METHODS

A cross-sectional study was carried out in 21 adult IGHD subjects, and 21 age- and gender-matched controls. Objective sleep assessment included polygraphic records of the awake, stages NREM [N1 (drowsiness), N2 and N3 (already sleeping)] and REM (R). Subjective evaluation included the Pittsburgh Sleep Quality Index, the Insomnia Severity Index and the Epworth Sleepiness Scale.

RESULTS

IGHD subjects showed a reduction in sleep efficiency (P = 0.007), total sleep time (P = 0.028), duration of N2 and R in minutes (P = 0.026 and P = 0.046 respectively), but had increased duration and percentage of N1 stage (P = 0.029 and P = 0.022 respectively), wake (P = 0.007) and wake-time after sleep onset (P = 0.017). There was no difference in N3 or in sleep quality questionnaire scores.

CONCLUSION

Patients with IGHD due to GHRH resistance exhibit objective reduction in the sleep quality, with changes in NREM and REM sleep, with no detectable subjective consequences. GHRH resistance seems to have a preponderant role over GHD in the sleep quality of these subjects.

Pituitary diseases and sleep disorders

PURPOSE OF REVIEW

Patients with pituitary diseases have decreased quality of life. Sleep disorders are prevalent among patients with pituitary diseases and contribute to decreased quality of life.

RECENT FINDINGS

Patients previously treated for compression of the optic chiasm by surgery, and in some cases postoperative radiotherapy, suffer from sleep disorders. These are characterized by decreased sleep quality, delayed onset of sleep, and daytime sleepiness. Circumstantial evidence suggests that this may be caused by hypothalamic dysfunction. A challenging speculation is that previous compression of the optic chiasm compromised the function of the retinohypothalamic tract. Through this tract the eyes convey information on day-night cycles to the hypothalamic nuclei. Patients with acromegaly, even despite biochemical control, suffer frequently from obstructive sleep apnea. Patients with Cushing's disease suffer from fragmented sleep, sleep apnea, and snoring. Prolactinomas do not seem to affect sleep characteristics. The association between appropriately substituted pituitary insufficiency and sleep disorders is less clear. The effects of recombinant human growth hormone on sleep characteristics in adults are inconsistent.

SUMMARY

Pituitary disorders are associated with different sleep disorders. Different studies point to irreversible changes in sleep-wake rhythmicity in patients treated previously for pituitary tumors with chiasm compression. VIDEO ABSTRACT.

Alterations in diurnal rhythmicity in patients treated for nonfunctioning pituitary macroadenoma: a controlled study and literature review

OBJECTIVE

Patients treated for nonfunctioning pituitary macroadenomas (NFMAs) have fatigue and alterations in sleep characteristics and sleep-wake rhythmicity frequently. As NFMAs often compress the optic chiasm, these complaints might be related to dysfunction of the adjacent suprachiasmatic nucleus (SCN). We aimed to explore whether indirect indices of SCN functioning are altered in the long term after surgery for NFMAs.

METHODS

We studied 17 NFMA patients in long-term remission after transsphenoidal surgery, receiving adequate and stable hormone replacement for hypopituitarism, and 17 control subjects matched for age, gender, and BMI. Indirect indices of SCN function were assessed from 24-h ambulatory recordings of skin and core body temperatures, blood pressure, and salivary melatonin levels. Altered melatonin secretion was defined as an absence of evening rise, considerable irregularity, or daytime values >3 pg/ml. We additionally studied eight patients treated for craniopharyngioma.

RESULTS

Distal-proximal skin temperature gradient did not differ between NFMAs and control subjects, but proximal skin temperature was decreased during daytime (P=0.006). Core body temperature and non-dipping of blood pressure did not differ, whereas melatonin secretion was often altered in NFMAs (OR 5.3, 95% CI 0.9-30.6). One or more abnormal parameters (≥2.0 SDS of control subjects) were observed during nighttime in 12 NFMA patients and during daytime in seven NFMA patients. Similar patterns were observed in craniopharyngioma patients.

CONCLUSION

Heterogeneous patterns of altered diurnal rhythmicity in skin temperature and melatonin secretion parameters were observed in the majority of patients treated for NFMAs. On a group level, both NFMA and craniopharyngioma patients showed a lower daytime proximal skin temperature than control subjects, but other group averages were not significantly different. The observations suggest altered function of central (or peripheral) clock machinery, possibly by disturbed entrainment or damage of the hypothalamic SCN by the suprasellar macroadenoma or its treatment.

Arginine vasopressin immunoreactivity is decreased in the hypothalamic suprachiasmatic nucleus of subjects with suprasellar tumors

Suprasellar tumors with compression of the optic chiasm are associated with an impaired sleep-wake rhythm. We hypothesized that this reflects a disorder of the biological clock of the human brain, the suprachiasmatic nucleus (SCN), which is located just above the optic chiasm. In order to test this hypothesis, we investigated the expression of two key neuropeptides of the SCN, that is, arginine vasopressin (AVP) and vasoactive intestinal peptide (VIP), as assessed by quantitative immunocytochemistry in post-mortem hypothalamic tissue of patients with a suprasellar tumor inducing permanent visual field defects. Post-mortem hypothalamic tissue of 5 patients with a suprasellar tumor inducing permanent visual field defects (acromegaly n = 2, nonfunctioning macro-adenoma n = 1, macroprolactinoma n = 1, infundibular metastasis of a colorectal adenocarcinoma n = 1) and 15 age- and gender-matched controls was obtained from the Netherlands Brain Bank. Total AVP immunoreactivity in the SCN was lower in patients with a suprasellar tumor than in controls (P = 0.03). By contrast, total VIP immunoreactivity was not different between patients and controls (P = 0.44). Suprasellar tumors leading to permanent visual field defects are associated with reduced AVP, but not VIP immunoreactivity, in the SCN. These findings raise the possibility that selective impairment of the SCN contributes to sleep-wake disturbances in these patients.

Impact of GH replacement therapy on sleep in adult patients with GH deficiency of pituitary origin

OBJECTIVES

We previously reported that adult patients with GH deficiency (GHD) due to a confirmed or likely pituitary defect, compared with healthy controls individually matched for age, gender, and BMI, have more slow-wave sleep (SWS) and higher delta activity (a marker of SWS intensity). Here, we examined the impact of recombinant human GH (rhGH) therapy, compared with placebo, on objective sleep quality in a subset of patients from the same cohort.

DESIGN

Single-blind, randomized, crossover design study.

METHODS

Fourteen patients with untreated GHD of confirmed or likely pituitary origin, aged 22-74 years, participated in the study. Patients with associated hormonal deficiencies were on appropriate replacement therapy. Polygraphic sleep recordings, with bedtimes individually tailored to habitual sleep times, were performed after 4 months on rhGH or placebo.

RESULTS

Valid data were obtained in 13 patients. At the end of the rhGH treatment period, patients had a shorter sleep period time than at the end of the placebo period (479±11 vs 431±19 min respectively; P=0.005), primarily due to an earlier wake-up time, and a decrease in the intensity of SWS (delta activity) (559±125 vs 794±219 μV(2) respectively; P=0.048).

CONCLUSIONS

Four months of rhGH replacement therapy partly reversed sleep disturbances previously observed in untreated patients. The decrease in delta activity associated with rhGH treatment adds further evidence to the hypothesis that the excess of high-intensity SWS observed in untreated pituitary GHD patients is likely to result from overactivity of the hypothalamic GHRH system due to the lack of negative feedback inhibition by GH.

Imaging of serotonin transporters with [123I]FP-CIT SPECT in the human hypothalamus

BACKGROUND

Serotonergic neurons in the rodent hypothalamus are implicated in key neuroendocrine and metabolic functions, including circadian rhythmicity. However, the assessment of the serotonergic system in the human hypothalamus in vivo is difficult as delineation of the hypothalamus is cumbersome with conventional region-of-interest analysis. In the present study, we aimed to develop a method to visualize serotonin transporters (SERT) in the hypothalamus. Additionally, we tested the hypothesis that hypothalamic SERT binding ratios are different between patients with hypothalamic impairment (HI), pituitary insufficiency (PI), and control subjects (C).

METHODS

SERT availability was determined in 17 subjects (6 HI, 5 PI, and 6 healthy controls), 2 h after injection of 123I-N-ω-fluoropropyl-2β-carboxymethoxy-3β-(4-iodophenyl) nortropane ([123I]FP-CIT), using single-photon emission computed tomography (performed on a brain-dedicated system) fused with individual magnetic resonance imaging (MRI) scans of the brain. The hypothalamus (representing specific SERT binding) and cerebellum (representing nonspecific binding) were manually delineated on each MRI to assess [123I]FP-CIT binding and specific-to-nonspecific binding ratios.

RESULTS

In each healthy subject, [123I]FP-CIT binding was higher in the hypothalamus than in the cerebellum, and the mean hypothalamic binding ratio of SERT was 0.29 ± 0.23. We found no difference in hypothalamic binding ratios between HI, PI, and control subjects (HI 0.16 ± 0.24, PI 0.45 ± 0.39, C 0.29 ± 0.23, p value 0.281).

CONCLUSIONS

We were able to demonstrate SERT binding in the human hypothalamus in vivo. However, we did not find altered hypothalamic SERT binding in patients with hypothalamic impairment.

TRIAL REGISTRATION

Netherlands Trial Register: NTR2520.