Bioavailability of Melatonin after Administration of an Oral Prolonged-Release Tablet and an Immediate-Release Sublingual Spray in Healthy Male Volunteers.

BACKGROUND: The benefit of exogenous melatonin is based on its bioavailability, which depends on the galenic form, the route of administration, the dosage, and the individual absorption and rate of hepatic metabolism. OBJECTIVE: The objective of this study is to investigate the bioavailability of melatonin after administration of an oral prolonged-release tablet (PR form) and an immediate-release sublingual spray (IR form). The main metabolite of melatonin, 6-sulfatoxymelatonin (6-SMT), was also measured, which has not been done in previous studies. Its determination is important as an index of the hepatic transformation of melatonin. METHODS: In this single-center, open-label, randomized, crossover study, 14 healthy male volunteers received one tablet of the PR form (1.9 mg melatonin) or two sprays of the IR form (1 mg melatonin) during two visits separated by a washout period. Blood samples were collected over 7 and 9 h for the IR and PR form, respectively, to determine the main pharmacokinetic parameters. RESULTS: The observed kinetics were consistent with those expected for immediate and prolonged-release forms. Pulverization of the spray resulted in an early, high plasma melatonin peak (Cmax: 2332 ± 950 pg/mL; Tmax: 23.3 ± 6.5 min), whereas tablet intake produced a lower peak (Cmax: 1151 ± 565 pg/mL; Tmax: 64.2 ± 44.2 min; p < 0.001 for comparison of Cmax and Tmax) followed by a plasma melatonin plateau and a more prolonged decay over time. Plasma melatonin/6-SMT AUC0-540/420 ratio was 0.09 for the PR form and 0.16 for the IR form. Both galenic forms were well tolerated. CONCLUSIONS: The results suggest that the galenic forms containing melatonin assessed in this study are suitable for the treatment of certain sleep disorders such as sleep onset delay and transient nocturnal awakenings for the IR form and insomnia for the PR form. TRIAL REGISTRY: Registration number: NCT04574141.

Melatonin: From Pharmacokinetics to Clinical Use in Autism Spectrum Disorder.

The role of melatonin has been extensively investigated in pathophysiological conditions, including autism spectrum disorder (ASD). Reduced melatonin secretion has been reported in ASD and led to many clinical trials using immediate-release and prolonged-release oral formulations of melatonin. However, melatonin's effects in ASD and the choice of formulation type require further study. Therapeutic benefits of melatonin on sleep disorders in ASD were observed, notably on sleep latency and sleep quality. Importantly, melatonin may also have a role in improving autistic behavioral impairments. The objective of this article is to review factors influencing treatment response and possible side effects following melatonin administration. It appears that the effects of exposure to exogenous melatonin are dependent on age, sex, route and time of administration, formulation type, dose, and association with several substances (such as tobacco or contraceptive pills). In addition, no major melatonin-related adverse effect was described in typical development and ASD. In conclusion, melatonin represents currently a well-validated and tolerated treatment for sleep disorders in children and adolescents with ASD. A more thorough consideration of factors influencing melatonin pharmacokinetics could illuminate the best use of melatonin in this population. Future studies are required in ASD to explore further dose-effect relationships of melatonin on sleep problems and autistic behavioral impairments.

Melatonin Levels in Preterm and Term Infants and Their Mothers.

The prevention of perinatal brain damage following preterm birth remains a public health priority. Melatonin has been shown to be a promising neuroprotectant in neonatal preclinical models of brain damage, but few studies have investigated melatonin secretion in newborns. We hypothesized that melatonin circulating levels would be lower in preterm compared to term infants. We conducted a prospective, longitudinal, multicenter study to assess melatonin, and 6-sulfatoxy-melatonin (aMT6s) concentrations, measured by radioimmunoassay. Among 209 neonates recruited, 110 were born before 34 gestational weeks (GW) and 99 born after 34 GW. Plasma melatonin concentrations, measured at birth and on Day 3 were below detectable levels (≤7 pg/mL) in 78% and 81%, respectively, of infants born before 34 GW compared to 57% and 34%, respectively, of infants born after 34 GW. The distribution of plasma melatonin concentrations was found to be correlated with gestational age at both time-points (p < 0.001). Median urine aMT6s concentrations were significantly lower in infants born before 34 GW, both on Day 1 (230 ng/L vs. 533 ng/L, p < 0.0001) and on Day 3 (197 ng/L vs. 359 ng/L, p < 0.0001). In conclusion, melatonin secretion appears very low in preterm infants, providing the rationale for testing supplemental melatonin as a neuroprotectant in clinical trials.

Relationship Between Sex Steroids and Deterioration of Bone Microarchitecture in Older Men: The Prospective STRAMBO Study.

In older men, low estrogen levels are associated with poor bone microarchitecture. Data on androgens are discordant. We studied the link between baseline sex steroid levels (total 17ß -estradiol [17ßE2], total testosterone [tT], calculated bioavailable 17ßE2 [bio-17ßE2], and apparent free testosterone concentration [AFTC]) and bone microarchitecture deterioration assessed prospectively in a 820 older men followed for 8 years. Bone microarchitecture was assessed by HR-pQCT at baseline, then after 4 and 8 years. At both the skeletal sites, the bone microarchitecture deterioration rate did not correlate with serum levels of tT and 17ßE2. At the distal radius, cortical area (Ct.Ar) decreased more rapidly in the lowest versus the highest AFTC quartile. At the distal tibia, cortical thickness (Ct.Th) decreased and trabecular area (Tb.Ar) increased more rapidly in the highest versus the lowest AFTC quartile. At the tibia, bone mineral content (BMC), total volumetric bone mineral density (Tt.vBMD), Ct.Th, and Ct.Ar decreased, whereas Tb.Ar increased faster in the lowest versus the highest bio-17ßE2 quartile. In men who had both AFTC and bio-17ßE2 in the lowest quartile (high-risk group), distal radius cortical vBMD (Ct.vBMD) decreased more rapidly compared with men who had both hormones in the three upper quartiles (reference group). At the distal tibia, Tt.vBMD, Ct.Th, Ct.Ar, and Ct.vBMD decreased, whereas Tb.Ar increased more rapidly in the high-risk group versus the reference group. In men receiving androgen deprivation therapy (ADT) for prostate cancer, BMC, Tt.vBMD, Ct.Th, Ct.Ar, and Ct.vBMD decreased, whereas Tb.Ar increased more rapidly than in men not receiving ADT at both the skeletal sites. Thus, in older men followed up prospectively, low levels of bio-17ßE2, and to a smaller extent AFTC, are associated with accelerated cortical bone deterioration. Cortical bone deterioration was strongly accelerated in men receiving ADT who had very low levels of all sex steroids. © 2019 American Society for Bone and Mineral Research.

Is circadian rhythmicity a prerequisite to coma recovery? Circadian recovery concomitant to cognitive improvement in two comatose patients.

Circadian rhythmicity (CR) is involved in the regulation of all integrated functions, from sleep-wake cycle regulation to metabolic function, mood and cognition. However, the interdependence of CR, cognition and consciousness has been poorly addressed. To clarify the state of CR in coma and to determine the chronological relationship between its recovery and consciousness after brain lesions, we conducted a longitudinal observational study investigating how the state of CR was chronologically related with the recovery of behavioural wakefulness, cognition and/or awareness. Among 16 acute comatose patients, we recruited two 37-year-old patients with a persistent disorder of consciousness, presenting diencephalic lesions caused by severe traumatic brain injuries. Two biological urinary markers of CR were explored every 2 hours during 24 hours (6-sulfatoxymelatonin, free cortisol) with a dedicated methodology to extract the endogenous component of rhythmicity (environmental light recording, near-constant-routine protocol, control of beta-blockers). They presented an initial absence of rhythmic secretions and a recovered CR 7-8 months later. This recovery was not associated with the restoration of behavioural wakefulness, but with an improvement of cognition and awareness (up to the minimally conscious state). MRI showed a lesion pattern compatible with the interruption of either the main hypothalamic-sympathetic pathway or the accessory habenular pathway. These results suggest that CR may be a prerequisite for coma recovery with a potential but still unproven favourable effect on brain function of the resorted circadian melatonin secretion and/or the functional recovery of the suprachiasmatic nucleus (SCN). Assessing circadian functions by urinary melatonin should be further explored as a biomarker of cognition reappearance and investigated to prognosticate functional recovery.

High bicarbonate levels in narcoleptic children.

The objective of this study was to evaluate the levels of plasma bicarbonate levels in narcoleptic children. Clinical, electrophysiological data and bicarbonate levels were evaluated retrospectively in children seen in our paediatric national reference centre for hypersomnia. The cohort included 23 control subjects (11.5 ± 4 years, 43% boys) and 51 patients presenting de-novo narcolepsy (N) (12.7 ± 3.7 years, 47% boys). In narcoleptic children, cataplexy was present in 78% and DQB1*0602 was positive in 96%. The control children were less obese (2 versus 47%, P = 0.001). Compared with control subjects, narcoleptic children had higher bicarbonate levels (P = 0.02) as well as higher PCO2 (P < 0.01) and lower venous pH gas (P < 0.01). Bicarbonate levels higher than 27 mmol L(-1) were found in 41.2% of the narcoleptic children and 4.2% of the controls (P = 0.001). Bicarbonate levels were correlated with the Adapted Epworth Sleepiness Scale (P = 0.01). Narcoleptic patients without obesity often had bicarbonate levels higher than 27 mmol L (-1) (55 versus 25%, P = 0.025). No differences were found between children with and without cataplexy. In conclusion, narcoleptic patients had higher bicarbonate plasma levels compared to control children. This result could be a marker of hypoventilation in this pathology, provoking an increase in PCO2 and therefore a respiratory acidosis, compensated by an increase in plasma bicarbonates. This simple screening tool could be useful for prioritizing children for sleep laboratory evaluation in practice.

The supramammillary nucleus and the claustrum activate the cortex during REM sleep.

Evidence in humans suggests that limbic cortices are more active during rapid eye movement (REM or paradoxical) sleep than during waking, a phenomenon fitting with the presence of vivid dreaming during this state. In that context, it seemed essential to determine which populations of cortical neurons are activated during REM sleep. Our aim in the present study is to fill this gap by combining gene expression analysis, functional neuroanatomy, and neurochemical lesions in rats. We find in rats that, during REM sleep hypersomnia compared to control and REM sleep deprivation, the dentate gyrus, claustrum, cortical amygdaloid nucleus, and medial entorhinal and retrosplenial cortices are the only cortical structures containing neurons with an increased expression of Bdnf, FOS, and ARC, known markers of activation and/or synaptic plasticity. Further, the dentate gyrus is the only cortical structure containing more FOS-labeled neurons during REM sleep hypersomnia than during waking. Combining FOS staining, retrograde labeling, and neurochemical lesion, we then provide evidence that FOS overexpression occurring in the cortex during REM sleep hypersomnia is due to projections from the supramammillary nucleus and the claustrum. Our results strongly suggest that only a subset of cortical and hippocampal neurons are activated and display plasticity during REM sleep by means of ascending projections from the claustrum and the supramammillary nucleus. Our results pave the way for future studies to identify the function of REM sleep with regard to dreaming and emotional memory processing.

Phase advance of circadian rhythms in Smith-Magenis syndrome: a case study in an adult man.

Melatonin secretion is usually increased during the daytime and decreased at night in Smith-Magenis syndrome (SMS) and consequently is not a pertinent marker of the circadian phase of the clock in these cases. No data on temperature rhythm is available in SMS, another reliable marker of circadian clock activity. For this reason, we assessed the 24h profiles of core temperature, sleep-wake cycle, hormones (plasma cortisol and melatonin) and plasma and urine 6sulfatoxy-melatonin, the main hepatic melatonin metabolism in a 31-year-old man diagnosed with a SMS. All circadian rhythms, especially temperature rhythm showed a phase-advance, associated with reverse melatonin secretion. Plasma and urine 6sulfatoxy-melatonin profiles showed normal melatonin catabolism and confirmed the reversed melatonin secretion. Taking in consideration the reverse melatonin secretion and the phase-advanced temperature rhythm, which is driven by the suprachiasmatic nucleus, we hypothesize that the central clock is more sensitive to afternoon than to morning melatonin. This different responsiveness to melatonin according to the time of the day (i.e. chronaesthesia) corroborates the phase response curve of melatonin secretion to exogenous melatonin.

Association between sex steroid levels and bone microarchitecture in men: the STRAMBO study.

CONTEXT: Data on the association between bone microarchitecture assessed by high-resolution peripheral quantitative computed tomography (HR-pQCT) and sex steroids in men are scarce. OBJECTIVE: Our aim was to determine the association between serum sex steroids and bone microarchitecture assessed by HR-pQCT in men. DESIGN: This is a cross-sectional analysis in the Structure of the Aging Men's Bones cohort. SETTING: The cohort was recruited from the general population. PARTICIPANTS: We examined 1169 male volunteers aged 20-87 years. No specific exclusion criteria were used. INTERVENTIONS: We collected blood samples and performed HR-pQCT at the distal radius and distal tibia. MAIN OUTCOME MEASURES: We tested the hypothesis that low sex steroid levels are associated with poor bone microarchitecture in men. RESULTS: Men aged younger than 65 years with bioavailable 17ß-estradiol (bio-17ß-E2) levels of14.4 pmol/L or less had higher cross-sectional and trabecular areas vs men with bio-17ß-E2 greater than 14.4 pmol/L. In men aged 65 years or older, the higher the apparent free T concentration (AFTC), the higher was the distal tibia cortical density (P < .05). Cortical density and thickness as well as total and trabecular density increased with higher bio-17ß-E2 levels. Similar results were found after adjustment for limb length and body height. Men with low AFTC and low bio-17ß-E2 levels had lower cortical density and thickness at both skeletal sites compared with the reference group. In men with AFTC less than 272 pmol/L, those with low bio-17ß-E2 less than 25 pmol/L had lower cortical density and thickness at both skeletal sites vs men having higher bio-17ß-E2 levels. CONCLUSION: In men aged 65 years and older, low bio-17ß-E2 levels were associated with poor cortical bone status and, to smaller extent, lower trabecular density.

Aging of non-visual spectral sensitivity to light in humans: compensatory mechanisms?

The deterioration of sleep in the older population is a prevalent feature that contributes to a decrease in quality of life. Inappropriate entrainment of the circadian clock by light is considered to contribute to the alteration of sleep structure and circadian rhythms in the elderly. The present study investigates the effects of aging on non-visual spectral sensitivity to light and tests the hypothesis that circadian disturbances are related to a decreased light transmittance. In a within-subject design, eight aged and five young subjects were exposed at night to 60 minute monochromatic light stimulations at 9 different wavelengths (420-620 nm). Individual sensitivity spectra were derived from measures of melatonin suppression. Lens density was assessed using a validated psychophysical technique. Although lens transmittance was decreased for short wavelength light in the older participants, melatonin suppression was not reduced. Peak of non-visual sensitivity was, however, shifted to longer wavelengths in the aged participants (494 nm) compared to young (484 nm). Our results indicate that increased lens filtering does not necessarily lead to a decreased non-visual sensitivity to light. The lack of age-related decrease in non-visual sensitivity to light may involve as yet undefined adaptive mechanisms.

Alteration of daily and circadian rhythms following dopamine depletion in MPTP treated non-human primates.

Disturbances of the daily sleep/wake cycle are common non-motor symptoms of Parkinson's disease (PD). However, the impact of dopamine (DA) depletion on circadian rhythms in PD patients or non-human primate (NHP) models of the disorder have not been investigated. We evaluated alterations of circadian rhythms in NHP following MPTP lesion of the dopaminergic nigro-striatal system. DA degeneration was assessed by in vivo PET ([(11)C]-PE2I) and post-mortem TH and DAT quantification. In a light∶dark cycle, control and MPTP-treated NHP both exhibit rest-wake locomotor rhythms, although DA-depleted NHP show reduced amplitude, decreased stability and increased fragmentation. In all animals, 6-sulphatoxymelatonin peaks at night and cortisol in early morning. When the circadian system is challenged by exposure to constant light, controls retain locomotor rest-wake and hormonal rhythms that free-run with stable phase relationships whereas in the DA-depleted NHP, locomotor rhythms are severely disturbed or completely abolished. The amplitude and phase relations of hormonal rhythms nevertheless remain unaltered. Use of a light-dark masking paradigm shows that expression of daily rest-wake activity in MPTP monkeys requires the stimulatory and inhibitory effects of light and darkness. These results suggest that following DA lesion, the central clock in the SCN remains intact but, in the absence of environmental timing cues, is unable to drive downstream rhythmic processes of striatal clock gene and dopaminergic functions that control locomotor output. These findings suggest that the circadian component of the sleep-wake disturbances in PD is more profoundly affected than previously assumed.

Dynamics of oxidative stress and urinary excretion of melatonin and its metabolites during acute ischemic stroke.

Oxidative stress is a leading cause of neuronal damage in ischemic stroke. Melatonin may play a role in the antioxidant response. Melatonin and its metabolites may be involved in the modulation of oxidative stress in human acute stroke. No data are available in humans to establish this relationship. In this context, on the first and the fifth days post-stroke, we assessed serum total antioxidant capacity (TAC) and urine levels of melatonin, 6-sulfatoxymelatonin (aMT6S), and N1-acetyl-N2-formyl-5-methoxykynuramine (AFMK), the last compound being produced in the brain after reaction of melatonin with reactive oxygen species. Compared to controls' values, TAC and levels of melatonin and aMT6S were reduced, without difference between the first and the fifth days post-stroke, whereas AFMK levels remained in the normal range at both time points. Melatonin catabolism might be speeded up in acute ischemic stroke in order to increase the antioxidant response.

In obese postmenopausal women, bone microarchitecture and strength are not commensurate to greater body weight: the Os des Femmes de Lyon (OFELY) study.

Obesity is associated with higher areal bone density (aBMD) but its protective effect on the risk of fracture is controversial. We aimed to analyze bone microarchitecture and biomechanical properties in obese (OB) postmenopausal French women compared with normal weight (NW) women. A matched case-control study from the Os des Femmes de Lyon (OFELY) cohort was conducted in 63 OB women (body mass index [BMI] > 30, mean age 69 ± 8 years) age-matched with 126 NW women (19 ≤ BMI ≤ 25). Bone architecture was measured with high-resolution pQCT at the distal radius and tibia and bone strength was assessed by micro-finite element analysis (µFEA). aBMD, total body fat mass (FM) and lean mass (LM) were measured by dual-energy X-ray absorptiometry (DXA). aBMD was 15% higher at the total hip in OB compared with NW women. At the radius, OB had 13% and 14% higher volumetric total and trabecular bone densities, 11% higher cortical thickness, 13% greater trabecular number, and 22% lower distribution of trabecular separation compared with NW (p adjusted for height, physical activity, and medication use, <0.01 for all). Differences of a similar magnitude were found at the distal tibia. At both sites, µFEA showed significant higher values of bone strength in OB compared to controls. After normalizing values for individual body weight, we observed that all the parameters were relatively lower in OB compared to NW women. The increase of FM was fourfold greater than the increase of LM in OB. The effect of FM on bone parameters was more pronounced at the tibia compared to the non-weight-bearing site. Nevertheless, the coefficients of correlation were about one-half of those of LM for the biomechanical parameters. We conclude that higher absolute values of bone densities, cortical and trabecular architecture, and strength indices were not in proportion to the excess of BMI and particularly of FM in obese postmenopausal French women.

Aging-like circadian disturbances in folate-deficient mice.

The elderly population shows various circadian disturbances, including dampened amplitude of rhythmicity and decreased responsiveness to light. The common poor folate status in the elderly might account for these aging-related circadian disturbances. To test this hypothesis, we investigated whether folate deficiency in mice affects circadian oscillations of the master clock in the suprachiasmatic nuclei, and the shifting responses to light. Mice fed a diet without folate for 6 weeks displayed markedly reduced (4.5-fold) erythrocyte folate concentration and increased (2.3-fold) homocysteinemia compared with control mice. Folate deficiency decreased the circadian amplitude of vasopressin and the clock protein PERIOD 2 (PER2) in the master clock, slowed the rate of re-entrainment of behavioral rhythms after delayed light-dark cycle and reduced light-induced phase-delays, without detectable morphologic changes in the retina, such as the number of melanopsinergic ganglion cells, that might have impaired photodetection. In conclusion, folate deficiency and consecutive hyperhomocysteinemia led to dampened PER2 and vasopressin oscillations in the master clock and reduced responsiveness to photic resetting, which constitute hallmarks of aging effects on circadian rhythmicity.

Persistence of fertility despite semen alterations in a pinealectomised patient treated with melatonin.

OBJECTIVES: Little is known about the effect of chronic melatonin treatment on human reproductive function. We report here on the effect of 10 months treatment with a controlled-release melatonin preparation (Circadin®, 2 mg) on spermatogenesis and gonadotropic hormone status in a pinealectomised patient whose melatonin secretion was abolished. METHODS: Semen analysis, hormone (Follicle Stimulating Hormone (FSH), Luteinizing Hormone (LH), inhibin B, prolactin, testosterone and estradiol) and Sex Hormone-Binding Globulin (SHB G) concentrations were determined before and at the end of 4 and 10 months of, treatment. RESULTS: At the end of treatment, testosterone, sex hormone-binding globulin, prolactin and inhibin B levels did not display significant variation with time, whereas FSH and LH levels showed a tendency to a decrease, but remained in the normal range. Sperm concentration and total spermatozoa count dropped below the lower limit of the reference range during melatonin treatment, whereas motility and normal form percentages remained in the normal range. Fertility was preserved, since the patient's wife became pregnant during month 10 of melatonin treatment and gave birth to a healthy female baby. CONCLUSIONS: this isolated clinical observation shows that more investigations in large patient series are needed to document possible side-effects of melatonin administration on male reproductive function. One should therefore be cautious about melatonin prescription for circadian rhythm sleep disorders in young males.

Pregnant French women living in the Lyon area are iodine deficient and have elevated serum thyroglobulin concentrations.

BACKGROUND: Iodine deficiency (ID) remains common in Europe, and may be especially detrimental during pregnancy. The aim of our study was to assess iodine status and thyroid function in healthy pregnant women in the Lyon metropolitan area. METHODS: In a cross-sectional study, healthy pregnant women (n=228) with no history of thyroid disease were consecutively recruited from an obstetric clinic during all trimesters. Thyrotropin (TSH), free thyroxine (FT4), anti-thyroid peroxidase (anti-TPO) antibodies, thyroglobulin (Tg), and urinary iodine concentration (UIC) (n=100) were measured. Thyroid functions were compared with those in a control group of nonpregnant adults. RESULTS: The median (range) UIC was 81 (8-832) µg/L, and 77% of pregnant women had a UIC <150 µg/L, indicating inadequate iodine intake. Overall, 11% of women had abnormal TSH or anti-TPO. The median FT4 (pmol/L) was 14.9, 12.6, and 11.5 in the first, second, and third trimesters, respectively. The median Tg in pregnant women was 16.2 µg/L, did not differ across trimesters, and was significantly higher than in the control group of nonpregnant adults (11.7 µg/L) (p=0.02). Controlling for maternal age and week of gestation, UIC was not a significant predictor of any of the thyroid function tests. CONCLUSIONS: Pregnant women in the Lyon area are iodine deficient and have increased serum Tg concentrations compared with nonpregnant controls, likely due to physiological thyroid hyperstimulation during gestation exacerbated by ID.

Clinical characteristics and outcome of acromegaly induced by ectopic secretion of growth hormone-releasing hormone (GHRH): a French nationwide series of 21 cases.

CONTEXT: Ectopic GHRH secretion is a rare cause of acromegaly, and case reports are mainly isolated. SETTING: From the registry of the sole laboratory performing plasma GHRH assays in France, we identified cases of ectopic GHRH secretion presenting with acromegaly between 1983 and 2008. PATIENTS: Twenty-one patients aged 14-77 yr were identified from 12 French hospitals. Median GHRH was 548 (270-9779) ng/liter. MAIN OUTCOME MEASURES: Outcome measures included description of tumor features and outcome and the relation between plasma GHRH values and tumor site, size, and spread. RESULTS: The primary neuroendocrine tumor was identified for 20 of 21 patients (12 pancreatic, seven bronchial, one appendicular). Tumors were large (10-80 mm), identified on computed tomography scan in 18 cases and by endoscopic ultrasound and somatostatin receptor scintigraphy in two. Somatostatin receptor scintigraphy had a similar sensitivity to computed tomography scan (81 vs. 86%). Tumors were all well differentiated; 47.6% had metastasized at the time of diagnosis of acromegaly. After a median follow-up of 5 yr, 85% of patients were alive. Ninety-one percent of patients whose tumor was completely removed were considered in remission, and most had normalized plasma GHRH. The remaining patients were treated with somatostatin analogs: IGF-I normalized except for one patient who required pegvisomant, but GHRH levels remained elevated. No correlations were found between GHRH levels and tumor site or size or the existence of metastases. Identification of increased plasma GHRH during follow-up was an accurate indicator of recurrence. CONCLUSIONS: The prognosis of endocrine tumors responsible for GHRH secretion appears relatively good. Plasma GHRH assay is an accurate tool for diagnosis and follow-up.

Folate depletion changes gene expression of fatty acid metabolism, DNA synthesis, and circadian cycle in male mice.

Folate is essential for purine and thymidylate biosynthesis and in methyl transfer for DNA methylation. Folate deficiency alters the secretion of melatonin, a hormone involved in circadian rhythm entrainment, and causes hyperhomocysteinemia because of disruption of homocysteine metabolism. Adverse effects of homocysteine include the generation of free radicals, activation of proliferation or apoptosis, and alteration of gene expression. The liver is an important organ for folate metabolism, and its genome analysis has revealed numerous clock-regulated genes. The variations at the level of their expression during folate deficiency are not known. The aim of our study was to investigate the effects of folate deficiency on gene expression in the mouse liver. A control group receiving a synthetic diet and a folate-depleted group were housed for 4 weeks on a 12-hour/12-hour light/dark cycle. Three mice from each group were euthanized under dim red light at the beginning of the light cycle, and 3, at the beginning of the dark period. Gene expression was studied in a microarray analysis. Of the 53 genes showing modified daily expression in the controls, 52 showed a less marked or no difference after folate depletion. Only 1, lpin1, showed a more marked difference. Ten genes coding for proteins involved in lipid metabolism did not show a morning/evening difference in controls but did after folate depletion. This study shows that, in the mouse liver, dietary folate depletion leads to major changes in expression of several genes involved in fatty acid metabolism, DNA synthesis, and expression of circadian genes.

Age determines longitudinal changes in body composition better than menopausal and bone status: the OFELY study.

Long-term body composition (BC) changes and their determinants have been rarely explored. We aimed to evaluate BC changes in French women from the Os des Femmes de Lyon (OFELY) cohort and to explore several determinants of those changes. At baseline, premenopausal (PreM) women (n = 145) had lower fat body mass (FM) and greater lean body mass (LM), relative skeletal muscle mass index (RASM), and total body bone mineral content (TBBMC) compared with untreated postmenopausal (PostM) women (n = 412). During a 6-year follow-up, LM and RASM did not change, whereas a significant increase of FM and a decrease of TBBMC were observed in PreM (n = 88) and PeriM women (n = 44; women who became PostM during the follow-up). In untreated PostM women, FM increased, whereas LM, RASM, and TBBMC decreased (p < 0.0001). Age was a significant determinant of the changes in BC. After controlling for age, menopausal status was still a significant determinant only for changes in TBBMC. FM, LM, RASM, and TBBMC were higher in women with normal bone mineral density (BMD) compared with women with osteopenia or osteoporosis (p < 0.0001), but after adjusting for age, changes of BC were not significantly different according to the bone status. After controlling for age and menopausal status, levels of P1NP in the highest quartile were associated with a greater decrease of LM and RASM compared with lower levels. In conclusion, BC changes in French women over a 6-year follow-up showed a high interindividual variability. Aging may be the most important determinant of changes in body composition, rather than menopausal and bone status.

The impact of sleep deprivation and nighttime light exposure on clock gene expression in humans.

AIM: To examine the effect of acute sleep deprivation under light conditions on the expression of two key clock genes, hPer2 and hBmal1, in peripheral blood mononuclear cells (PBMC) and on plasma melatonin and cortisol levels. METHODS: Blood samples were drawn from 6 healthy individuals at 4-hour intervals for three consecutive nights, including a night of total sleep deprivation (second night). The study was conducted in April-June 2006 at the University Medical Centre Ljubljana. RESULTS: We found a significant diurnal variation in hPer2 and hBmal1 expression levels under baseline (P<0.001, F=19.7, df=30 for hPer2 and P<0.001, F=17.6, df=30 for hBmal1) and sleep-deprived conditions (P<0.001, F=9.2, df=30 for hPer2 and P<0.001, F=13.2, df=30 for hBmal1). Statistical analysis with the single cosinor method revealed circadian variation of hPer2 under baseline and of hBmal1 under baseline and sleep-deprived conditions. The peak expression of hPer2 was at 13:55 ± 1:15 hours under baseline conditions and of hBmal1 at 16:08 ± 1:18 hours under baseline and at 17:13 ± 1:35 hours under sleep-deprived conditions. Individual cosinor analysis of hPer2 revealed a loss of circadian rhythm in 3 participants and a phase shift in 2 participants under sleep-deprived conditions. The plasma melatonin and cortisol rhythms confirmed a conventional alignment of the central circadian pacemaker to the habitual sleep/wake schedule. CONCLUSION: Our results suggest that 40-hour acute sleep deprivation under light conditions may affect the expression of hPer2 in PBMCs..