Abnormal melatonin secretion in hypogonadal men: the effect of testosterone treatment

Melatonin secretion across puberty: A systematic review and meta-analysis

BACKGROUND

Melatonin levels decrease with aging and substantially during puberty. Studies have presented distinct melatonin levels in patients with disorders related to their pubertal development compared to healthy controls. The discrepancy suggests that a decrease in melatonin concentrations seen during adolescence might be related to the physical, hormonal, and/or neuronal alterations that occur during the pubertal period. The aim of this review was to analyze the literature reporting melatonin levels in healthy children and adolescents during puberty, and to look for a potential relationship.

METHODS

The Medline and Embase databases were searched on November 28th 2024, including all articles published from 1974 to 2024. Moreover, in the studies eligible for full-text review, a "snowball" search based by backwards referencing was carried out to identify additional studies. This means going through the references of the eligible studies, to find potential other articles relevant for our review and met our inclusion criteria. Lastly, a meta-analysis on serum melatonin concentrations with increasing age and Tanner status was performed.

RESULTS

21 studies were included. 12 studies found a decrease, 5 found no difference and 3 reported an increase in melatonin levels during pubertal advancement. One study could not report secretory alterations but was eligible for inclusion in the meta-analysis. This analysis revealed that Tanner stages were significantly associated with decreasing average as well as peak concentrations of melatonin.

CONCLUSION

The simultaneous occurrence of pubertal progression and chronological aging complicates potential reasons to the decrease observed. However, possible explanations could be related to sex hormones, physical properties of puberty or light exposure. To justify these explanations research in controlled conditions along with biochemical and clinical assessment of pubertal status is needed.

Relative hyperestrogenism in Klinefelter Syndrome: results from a meta-analysis

OBJECTIVE

Klinefelter Syndrome (KS) is classically described as characterized by hyperestrogenism, although solid evidence is lacking. This study aims to test the hypothesis that men with KS have higher serum estradiol than normal controls.

DESIGN

Meta-analysis of all studies extracted by MEDLINE from 1942 to 31 January 2018. All studies reporting serum estradiol measurement were considered, among them only case-control studies were included in the meta-analysis.

METHODS

Meta-analysis was conducted according to the PRISMA statement using RevMan.

RESULTS

Out of 4120 articles, 23 case-control studies, 14 case series, and 19 case reports reported data on serum estradiol. A total of 707 KS and 1019 controls were included in the meta-analysis. Serum estradiol was slightly, but significantly higher in KS than controls (mean difference 4.25 pg/mL; CI: 0.41, 8.10 pg/mL; p = 0.030). This difference was lost considering only studies using estradiol assays with good accuracy (5.48 pg/mL, CI: -2.11, 13.07 pg/mL; p = 0.160). Serum testosterone and estradiol/testosterone ratio were significantly lower and higher in KS than controls, respectively. Data from KS case series and case reports confirmed that serum estradiol is within the normal ranges.

CONCLUSIONS

Serum estradiol is not increased in KS although slightly higher than controls. However, the meta-analysis that included only studies using a serum estradiol assay with good accuracy showed no difference in serum estradiol between KS and controls. The traditional belief that KS is associated with elevated serum estradiol should be reconsidered. This meta-analysis shows that men with KS have relative hyperestrogenism (increased estradiol/testosterone ratio) compared to controls.

Complementary and Integrative Approaches for Pediatric Headache

In this article, the use of complementary and integrative medicine for the management of pediatric headache is reviewed. Despite limited numbers of studies for pediatric headaches, children and families seek these services. Integrative medicine focuses on treating the whole person, integrating conventional medicine with mind-body-spirit methods. Nutriceuticals include dietary supplements in the form of vitamins (vitamin D), minerals (magnesium), coenzyme Q, butterbur, and melatonin. Acupuncture, stimulation, physical therapy and Transcutaneous Electrical Nerve Stimulations (TENS) or Transcranial Magnetic Stimulation (TMS) may also be useful in selected patients. The efficacy of all these therapeutic alternatives in pediatric headache is presented here. Primary care providers, neurologists, and headache specialists alike need to be informed of such interventions and integrate these approaches, when appropriate, in the management of children with headaches.

Ultrastructure of Intervertebral Disc and Vertebra-Disc Junctions Zones as a Link in Etiopathogenesis of Idiopathic Scoliosis

Background Context. There is no general accepted theory on the etiology of idiopathic scoliosis (IS). An important role of the vertebrae endplate physes (VEPh) and intervertebral discs (IVD) in spinal curve progression is acknowledged, but ultrastructural mechanisms are not well understood. Purpose. To analyze the current literature on ultrastructural characteristics of VEPh and IVD in the context of IS etiology. Study Design/Setting. A literature review. Results. There is strong evidence for multifactorial etiology of IS. Early wedging of vertebra bodies is likely due to laterally directed appositional bone growth at the concave side, caused by a combination of increased cell proliferation at the vertebrae endplate and altered mechanical properties of the outer annulus fibrosus of the adjacent IVD. Genetic defects in bending proteins necessary for IVD lamellar organization underlie altered mechanical properties. Asymmetrical ligaments, muscular stretch, and spine instability may also play roles in curve formation. Conclusions. Development of a reliable, cost effective method for identifying patients at high risk for curve progression is needed and could lead to a paradigm shift in treatment options. Unnecessary anxiety, bracing, and radiation could potentially be minimized and high risk patient could receive surgery earlier, rendering better outcomes with fewer fused segments needed to mitigate curve progression.

Melatonin and the skeleton

Melatonin may affect bone metabolism through bone anabolic as well as antiresorptive effects. An age-related decrease in peak melatonin levels at nighttime is well documented, which may increase bone resorption and bone loss in the elderly. In vitro, melatonin reduces oxidative stress on bone cells by acting as an antioxidant. Furthermore, melatonin improves bone formation by promoting differentiation of human mesenchymal stem cell (hMSC) into the osteoblastic cell linage. Bone resorption is reduced by increased synthesis of osteoprogeterin (OPG), a decoy receptor that prevents receptor activator of NK-κB ligand (RANKL) in binding to its receptor. Moreover, melatonin is believed to reduce the synthesis of RANKL preventing further bone resorption. In ovariectomized as well as nonovariectomized rodents, melatonin has shown beneficial effects on bone as assessed by biochemical bone turnover markers, DXA, and μCT scans. Furthermore, in pinealectomized animals, bone mineral density (BMD) is significantly decreased compared to controls, supporting the importance of sufficient melatonin levels. In humans, dysfunction of the melatonin signaling pathway may be involved in idiopathic scoliosis, and the increased fracture risk in nighttime workers may be related to changes in the circadian rhythm of melatonin. In the so-far only randomized study on melatonin treatment, no effects were, however, found on bone turnover markers. In conclusion, melatonin may have beneficial effects on the skeleton, but more studies on humans are warranted in order to find out whether supplementation with melatonin at bedtime may preserve bone mass and improve bone biomechanical competence.

Theoretical aspects of autism: biomarkers--a review

Autism is dramatically increasing in incidence and is now considered an epidemic. There are no objective means to diagnose the disorder. Diagnosis is made subjectively, based on the perceived behavior of the subject. This review presents an approach toward development of an objective measure of autism. Covering the literature from 1943 to the present in the PubMed and Ovid Medline databases, this review summarizes evidence of hormones, metabolites, amino acids, and other biomarkers present in significantly different quantities in autistic subjects compared to age- and sex-matched controls. These differences can be measured in the gastrointestinal, immunologic, neurologic, and toxicologic systems of the body, with some biomarkers showing ubiquitous application. In addition, there are unifying concepts, i.e., increased vulnerability to oxidative stress, immune glutamatergic dysfunction, and pineal gland malfunction. The variances of the biomarkers from the norm present the opportunity to create biomarker arrays that when properly developed and analyzed could result in an objective diagnosis with a ranking of the severity of autism for each subject. The contribution of each biomarker to the overall diagnosis could be calculated, thus providing a profile pattern unique to the individual. This profile could consequently provide information for therapeutic interventions on an individual basis.

Associations among hypogonadism, C-reactive protein, symptom burden, and survival in male cancer patients with cachexia: a preliminary report

CONTEXT

Cachexia is characterized by muscle wasting, anorexia, and elevated inflammatory markers. In patients without cancer, hypogonadism is associated with lower lean body mass, increased symptom burden, and decreased survival. Hypogonadism in cancer cachexia could exacerbate symptoms, facilitate a proinflammatory state, and decrease survival.

OBJECTIVES

To explore the relationships among these factors, a retrospective study of male cancer patients was conducted.

METHODS

The charts of 98 consecutive male patients referred to a cachexia clinic at a comprehensive cancer center were reviewed. All patients reported weight loss of >5% within the preceding six months; the median age was 60 years. Fifty-seven (58%) had serum C-reactive protein (CRP), and 68 (69%) had total testosterone evaluated. Symptoms were evaluated by the Edmonton Symptom Assessment Scale.

RESULTS

Median CRP was 20mg/L, and median testosterone level was 185 ng/dL (6.42 nmol/L) (normal > or = 240 ng/dL or 8.36 nmol/L). There was an inverse correlation between testosterone and CRP levels (P<0.01). Lower testosterone was associated with increased dyspnea and insomnia (P<0.05). Poor appetite and insomnia (P<0.05) correlated with elevated CRP. Survival of patients with testosterone levels < or = 185 ng/dL (6.42 nmol/L) was decreased compared with that of those with levels >185 ng/dL (13 vs. 62 weeks, P=0.004). Patients with CRP levels >10mg/L had decreased survival compared with those with levels < or = 10mg/L (15 vs. 46 weeks, P=0.01). The combination of hypogonadism and elevated CRP was associated with poorer prognosis. Elevated CRP levels were associated with increased symptom burden and decreased survival. Low testosterone was associated with decreased survival and correlated inversely with CRP levels, dyspnea, and insomnia.

CONCLUSION

Our preliminary results suggest that testosterone and CRP may be additive or synergistic as markers for survival in male patients and could be useful in future prognostic models.

Longitudinal study of the simultaneous secretion of melatonin and leptin during normal puberty

BACKGROUND/AIMS

Pubertal changes are a consequence of the activation of the hypothalamic-pituitary-gonadal axis due to an increase in the frequency and magnitude of pulses of gonadotropin-releasing hormone (GnRH), which may depend on the intrinsic properties of the neurons of the hypothalamic arcuatus nucleus, or on the influence of neurotransmitters and/or neuromodulators. We evaluated the serum concentrations of melatonin and leptin in healthy prepubertal and adolescent subjects of both sexes, to define their participation at the initial stages and during the progression of pubertal development.

METHODS

80 pediatric subjects (47 females and 33 males), aged 6-18 years, were divided into 2 groups, prepubertal (n = 25) and adolescent (n = 55), according to the absence or presence, respectively, of physical signs of pubertal development. The subjects were assessed on two occasions: at the time of their inclusion in the study, and 12-18 months later when the subject had advanced one pubertal stage according to the Tanner classification. Blood was obtained in fasting for clinical purposes and for the hormonal study. Melatonin and leptin were measured by radioimmunoanalysis.

RESULTS

As described previously, melatonin decreases at the onset of puberty and during pubertal development. Both the absolute melatonin value and the decrease between evaluations tended to be greater in females; the variations were correlated with neither an increase in body weight nor with the degree of pubertal development. The concentration of leptin increased in both sexes with the progression of puberty, this value being 40% greater in women, and correlated with the indicators of an increase in body volume and fat accumulation. Although its concentration remained stable between evaluations for both sexes, among the males the association between leptin and pubertal development took place at the start of the process, while for the females we observed a significant overall association between pubertal stage and leptin concentration, this association being stronger at more advanced Tanner stages. Neither at the onset of puberty nor during its course did we observe any significant relation between melatonin concentration and any of the Tanner stages, whether for males or for females. Neither was there any correlation between the absolute values or rates of modification of melatonin and leptin.

CONCLUSION

According to the evolutionary dynamics of their respective concentrations, both initially and during pubertal progress, melatonin and leptin do not interact in the initiation or progression of human pubertal development, and do not seem to play a key role in this process.

Testosterone replacement therapy in male hypogonadism is not associated with increase of endothelin-1 levels

Differences in endothelin-1 (ET-1) blood plasma levels were established between healthy men and women. Little is known about vascular effects of testosterone and the interactions between sex hormones and endothelin. In order to study the relationship between ET-1 and testosterone in more detail, we have investigated 33 male patients with various forms of hypogonadism (13 with hypergonadotropic hypogonadism and 20 with hypogonadotropic hypogonadism). Fourteen age-matched healthy males served as controls. The basal ET-1 levels in patients with hypogonadism (0.96 +/- 0.12 fmol/mL) (mean +/- SEM) were significantly higher in comparison with the controls (0.44 +/- 0.04 fmol/mL), p < 0.01. Fifteen individuals of these patients were studied during the therapy with testosterone depot 250 mg i.m. The ET-1 levels decreased in this group from 0.99 +/- 0.22 to 0.78 +/- 0.14 fmol/mL at the third and to 0.76 +/- 0.25 fmol/mL at the sixth month of the medication, respectively. The differences were not significant compared with the initial levels, but the concentrations at the sixth month of the treatment were not statistically different in comparison with the ET-1 levels of the controls. There was no significant difference in lipid data between patients before and during testosterone medication, except for the high-density lipoprotein cholesterol, which decreased at the third month of the treatment. Our results show that plasma ET-1 levels in males with hypogonadism are elevated with a tendency to decrease after testosterone administration. The optimum testosterone is not associated with enhanced cardiovascular risk as far as ET-1 plasma levels and lipids are concerned.

Testosterone Replacement Therapy for Treatment Refractory Cluster Headache

OBJECTIVES

To describe the clinical characteristics and laboratory findings of cluster headache patients whose headaches responded to testosterone replacement therapy.

BACKGROUND

Current evidence points to hypothalamic dysfunction, with increased metabolic hyperactivity in the region of the suprachiasmatic nucleus, as being important in the genesis of cluster headaches. This is clinically borne out in the circadian and diurnal behavior of these headaches. For years it has been recognized that male cluster headache patients appear overmasculinized. Recent neuroendocrine and sleep studies now point to an association between gonadotropin and corticotropin levels and hypothalamically entrained pineal secretion of melatonin.

RESULTS

Seven male and 2 female patients, seen between July 2004 and February 2005, and between the ages of 32 and 56, are reported with histories of treatment resistant cluster headaches accompanied by borderline low or low serum testosterone levels. The patients failed to respond to individually tailored medical regimens, including melatonin doses of 12 mg a day or higher, high flow oxygen, maximally tolerated verapamil, antiepileptic agents, and parenteral serotonin agonists. Seven of the 9 patients met 2004 International Classification for the Diagnosis of Headache criteria for chronic cluster headaches; the other 2 patients had episodic cluster headaches of several months duration. After neurological and physical examination all patients had laboratory investigations including fasting lipid panel, PSA (where indicated), LH, FSH, and testosterone levels (both free and total). All 9 patients demonstrated either abnormally low or low, normal testosterone levels. After supplementation with either pure testosterone in 5 of 7 male patients or combination testosterone/estrogen therapy in both female patients, the patients achieved cluster headache freedom for the first 24 hours. Four male chronic cluster patients, all with abnormally low testosterone levels, achieved remission.

CONCLUSIONS

Abnormal testosterone levels in patients with episodic or chronic cluster headaches refractory to maximal medical management may predict a therapeutic response to testosterone replacement therapy. In the described cases, diurnal variation of attacks, a seasonal cluster pattern, and previous, transient responsiveness to melatonin therapy pointed to the hypothalamus as the site of neurological dysfunction. Prospective studies pairing hormone levels and polysomnographic data are needed.

Melatonin: characteristics, concerns, and prospects

Melatonin is of great importance to the investigation of human biological rhythms. Its rhythm in plasma or saliva provides the best available measure of the timing of the internal circadian clock. Its major metabolite 6-sulphatoxymelatonin is robust and easily measured in urine. It thus enables long-term monitoring of human rhythms in real-life situations where rhythms may be disturbed, and in clinical situations where invasive procedures are difficult. Melatonin is not only a "hand of the clock"; endogenous melatonin acts to reinforce the functioning of the human circadian system, probably in many ways. Most is known about its relationship to sleep and the decline in core body temperature and alertness at night. Current perspectives also include a possible influence on major disease risk, arising from circadian rhythm disruption. Melatonin clearly has the ability to induce sleepiness and lower core body temperature during "biological day" and to change the timing of human rhythms when treatment is appropriately timed. It can entrain free-running rhythms and maintain entrainment in most blind and some sighted people. Used therapeutically it has proved a successful treatment for circadian rhythm disorder, particularly the non-24-h sleep wake disorder of the blind. Numerous other clinical applications are under investigation. There are, however, areas of controversy, large gaps in knowledge, and insufficient standardization of experimental conditions and analysis for general conclusions to be drawn with regard to most situations. The future holds much promise for melatonin as a therapeutic treatment. Most interesting, however, will be the dissection of its effects on human genes.

Altered melatonin secretion in hypogonadal men: clinical evidence

The pineal gland, through the rhythmic production of melatonin, seems to play an important role in the control of the reproductive function of many vertebrate species. In contrast, the effects of the pineal gland in humans and the relationship between gonadotropins and melatonin secretion are not yet clarified. On the basis of these considerations, the aim of the present study was to clarify whether melatonin serum concentrations were altered in males with different hypothalamo-pituitary-gonadal disturbances, in comparison to normal individuals. We have studied 36 individuals divided into three groups according to their gonadotropin status: normals, hypogonadotropic hypogonadism and hypergonadotropic hypogonadism. They were submitted to blood sample withdrawal at 03.00, 11.00 and 19.00 h for melatonin determination according to a radioimmunological method, without extraction of the sample. The results obtained in the present study suggest the existence of an interaction between the pituitary and the pineal gland. In fact, in the case of hypersecretion of gonadotropins, nocturnal melatonin release is reduced, while night melatonin secretion is increased in the opposite situation (hypogonadotropic hypogonadism). Both these endocrine pathologies are characterized by a reduced sexual steroid secretion; for that reason, this reduction cannot be regarded as responsible for the two opposite dysfunctions of melatonin release. In conclusion, our study shows that darkness-dependent release of melatonin in males with hypogonadotropic hypogonadism is significantly higher in comparison with the healthy men, while it is significantly reduced in patients with hypergonadotropic hypogonadism. A strong significant negative correlation is also found between gonadotropins and melatonin release.

Melatonin and sex hormone interrelationships--a review

Melatonin, the main hormone secreted by the pineal gland at night, plays a major role in regulating reproductive physiology in seasonal breeders and influences the age of sexual maturation in laboratory rodents. In humans these relationships are less clear. Evidence supporting a melatonin-reproductive hormone relationship relies on findings of abnormal melatonin secretion in disorders of the reproductive system and on pathologies of the pineal gland which are associated with clinical abnormalities of the reproductive hormones. Normal melatonin rhythms are closely related to those of the reproductive hormones during infancy and reciprocally correlated during puberty. The demonstration of melatonin receptors in the brain and in reproductive organs, together with the localization of sex hormone receptors in the pineal gland, further strengthen these relationships. However, it is not yet clear that these correlations are functionally related, as data on the antigonadal effects of exogenous melatonin on the reproductive hormones are not conclusively established.