Hearing status in adult individuals with lifetime, untreated isolated growth hormone deficiency

The state of Sergipe contribution to GH research: from Souza Leite to Itabaianinha syndrome

In the late 19^th century, José Dantas de Souza Leite, a physician born in Sergipe, published the first detailed clinical description of acromegaly under the guidance of the French neurologist Pierre Marie. In 2014, the Brazilian Society of Endocrinology and Metabolism created the "José Dantas de Souza Leite Award", which is granted every two years to a Brazilian researcher who has contributed to the development of endocrinology. In 2022, the award was given to another physician from Sergipe, Manuel Hermínio de Aguiar Oliveira, from the Federal University of Sergipe for the description of "Itabaianinha syndrome" in a cohort of individuals with isolated GH deficiency due to a homozygous inactivating mutation in the GH-releasing hormone receptor gene. This research, which was carried out over almost 30 years, was performed in partnership with Roberto Salvatori from Johns Hopkins University and in collaboration with other researchers around the world. This review article tells the story of Souza Leite, some milestones in the history of GH, and summarizes the description of Itabaianinha syndrome.

Insulin-like Growth Factor 1 Signaling in Mammalian Hearing

Insulin-like growth factor 1 (IGF-1) is a peptide hormone belonging to the insulin family of proteins. Almost all of the biological effects of IGF-1 are mediated through binding to its high-affinity tyrosine kinase receptor (IGF1R), a transmembrane receptor belonging to the insulin receptor family. Factors, receptors and IGF-binding proteins form the IGF system, which has multiple roles in mammalian development, adult tissue homeostasis, and aging. Consequently, mutations in genes of the IGF system, including downstream intracellular targets, underlie multiple common pathologies and are associated with multiple rare human diseases. Here we review the contribution of the IGF system to our understanding of the molecular and genetic basis of human hearing loss by describing, (i) the expression patterns of the IGF system in the mammalian inner ear; (ii) downstream signaling of IGF-1 in the hearing organ; (iii) mouse mutations in the IGF system, including upstream regulators and downstream targets of IGF-1 that inform cochlear pathophysiology; and (iv) human mutations in these genes causing hearing loss.

Growth Hormone and the Auditory Pathway: Neuromodulation and Neuroregeneration

Growth hormone (GH) plays an important role in auditory development during the embryonic stage. Exogenous agents such as sound, noise, drugs or trauma, can induce the release of this hormone to perform a protective function and stimulate other mediators that protect the auditory pathway. In addition, GH deficiency conditions hearing loss or central auditory processing disorders. There are promising animal studies that reflect a possible regenerative role when exogenous GH is used in hearing impairments, demonstrated in in vivo and in vitro studies, and also, even a few studies show beneficial effects in humans presented and substantiated in the main text, although they should not exaggerate the main conclusions.

Disruption of the GHRH receptor and its impact on children and adults: The Itabaianinha syndrome

Since 1994, we have been studying an extended kindred with 105 subjects (over 8 generations) residing in Itabaianinha County, in the Brazilian state of Sergipe, who have severe isolated GH deficiency (IGHD) due to a homozygous inactivating mutation (c.57 + 1G > A) in the GH releasing hormone (GHRH) receptor (GHRHR) gene. Most of these individuals have never received GH replacement therapy. They have low GH, and very low and often undetectable levels of serum IGF-I. Their principal physical findings are proportionate short stature, doll facies, high-pitched-voice, central obesity, wrinkled skin, and youthful hair with delayed pigmentation, and virtual absence of graying. The newborns from this cohort are of normal size, indicating that GH is not needed for intra-uterine growth. However, these IGHD individuals exhibit a myriad of phenotypic changes throughout the body, with a greater number of beneficial than harmful consequences. This GHRH signal disruption syndrome has been a valuable model to study the GH roles in body size and function. This reviews summarized the findings we have reported on this cohort.

An Investigation of Hearing (250-20,000 Hz) in Children with Endocrine Diseases and Evaluation of Tinnitus and Vertigo Symptoms

Introduction  Despite much advancement in medicine, endocrine and metabolic diseases remain an important cause of morbidity and even mortality in children.

Objective  The present study was planned to investigate the evaluation of hearing that also includes high frequencies, and the presence and degree of vertigo and tinnitus symptoms in pediatric patients diagnosed with endocrine diseases such as type 1 diabetes mellitus (DM), growth hormone deficiency (GHD), obesity, idiopathic short stature, and precocious puberty

Methods  The present study included a patient group of 207 children patients diagnosed with endocrine disease (95 males, 112 females; mean age 9.71 years old [range 6–16 years old]) and a control group including 55 healthy children who do not have any kind of chronic disease (26 males, 29 females; mean age 9.33 years old [range 6–16 years old]). The subjects underwent a hearing test with frequencies between 250 and 20,000 Hz. The vestibular and tinnitus symptoms were evaluated with the Pediatric Vestibular Symptom Questionnaire.

Results  Out of 207 patients in the patient group, 5 (2.4%) had hearing loss in pure tones, 10 (4.8%) had it in high frequencies, 40 (19.3%) had tinnitus symptoms, and 18 (8.7%) had vertigo symptoms. A total of 4 out of 207 patients in the study group (1.9%), 2 out of 59 with type 1 DM patients (3.4%), 1 out of 46 with GHD (2.2%), and 1 out of 43 obesity patients (2.3%) had hearing loss, vertigo, and tinnitus symptoms.

Conclusions  Our results suggest that some childhood endocrine diseases can cause some changes in the inner ear, although the exact cause is unknown. Perhaps, a detailed hearing and balance examination should be a routine in a child diagnosed with an endocrine disease. We think it is necessary to work on more comprehensive patient groups and tests in the future.

Vestibular function in severe GH deficiency due to an inactivating mutation in the GH-releasing hormone receptor gene

PURPOSE

Body balance involves the vestibular, visual, and proprioceptive systems. IGF-I is a GH-dependent key factor in the development and postnatal differentiation of the inner ear in mice and men, but its role in the vestibular function in adult humans is unknown. We have previously described a cohort of individuals with severe isolated GH deficiency (IGHD) caused by a mutation in the GHRH receptor (GHRHR) gene. These individuals complain of dizziness, exhibit mild sensorineural loss, but have normal postural balance, without increase in falls risk. The aim of this study was to evaluate their vestibular function.

METHODS

We performed physical examination (clinical head impulse and Fukuda dynamic stepping test), oculomotor (saccadic eye movements, spontaneous, semi-spontaneous and opotokinetic nystagmus, and pendular tracking) and caloric stimulation (postcaloric reflex and ocular fixation index) tests, in 15 GH-naïve IGHD (seven males) and 15 controls (five males).

RESULTS

IGHD subjects showed lower height and weight, with similar BMI to controls, and higher number of individuals with abnormal clinical head impulse test and abnormal oculomotor tests, namely the saccadic movements and the spontaneous nystagmus. There was a nonsignificant trend in abnormalities in the Fukuda stepping test and postcaloric reflex test.

CONCLUSIONS

Adult untreated IGHD individuals have higher prevalence of moderate peripheral vestibular impairment, and of abnormal vestibular-ocular reflex.

Understanding hormone and hormone therapies' impact on the auditory system

Hormones such as estrogen, progesterone, and aldosterone all demonstrate vital roles in sustaining auditory function through either the maintenance of cochlear neurons, up/down regulation of critical molecules (i.e., IGF-1, BDNF, etc.), or generation of the endocochlear potential. With disease and/or age, hormone expression begins to decline drastically, which ultimately affects cochlear structures and the integrity of cochlear cells. The following review explores the latest findings as well as realistic outcomes for hormone therapy treatment in the auditory system. This information could serve as a potential guide for patients considering hormone therapy as a medicinal choice to alleviate the signs of onset of presbycusis-age-related hearing loss. Additional scientific investigations could also be carried out to further enhance recent findings.

Advances in understanding of presbycusis

The pathophysiology of age-related hearing loss (ARHL), or presbycusis, involves a complex interplay between environmental and genetic factors. The fundamental biomolecular mechanisms of ARHL have been well described, including the roles of membrane transport, reactive oxygen species, cochlear synaptopathy, vascular insults, hormones, and microRNA, to name a few. The genetic basis underlying these mechanisms remains under-investigated and poorly understood. The emergence of genome-wide association studies has allowed for the identification of specific groups of genes involved in ARHL. This review highlights recent advances in understanding of the pathogenesis of ARHL, the genetic basis underlying these processes and suggests future directions for research and potential therapeutic avenues.

Walking and postural balance in adults with severe short stature due to isolated GH deficiency

OBJECTIVES

Walking and postural balance are extremely important to obtain food and to work. Both are critical for quality of life and ability to survive. While walking reflects musculoskeletal and cardiopulmonary systems, postural balance depends on body size, muscle tone, visual, vestibular and nervous systems. Since GH and IGF-I act on all these systems, we decided to study those parameters in a cohort of individuals with severe short stature due to untreated isolated GH deficiency (IGHD) caused by a mutation in the GHRH receptor gene. These IGHD subjects, despite reduction in muscle mass, are very active and have normal longevity.

METHODS

In a cross-sectional study, we assessed walking (by a 6-min walk test), postural balance (by force platform) and fall risk (by the 'Timed Up and Go' test) in 31 IGHD and 40 matched health controls.

RESULTS

The percentage of the walked distance measured in relation to the predicted one was similar in groups, but higher in IGHD, when corrected by the leg length. Absolute postural balance data showed similar velocity of unipodal support in the two groups, and better values, with open and closed eyes and unipodal support, in IGHD, but these differences became non-significant when corrected for height and lower-limb length. The time in 'Timed Up and Go' test was higher in IGHD cohort, but still below the cut-off value for fall risk.

CONCLUSION

IGHD subjects exhibit satisfactory walking and postural balance, without increase in fall risk.

Growth Hormone Deficiency: Health and Longevity

The important role of GH in the control of mammalian longevity was first deduced from extended longevity of mice with genetic GH deficiency (GHD) or GH resistance. Mice with isolated GHD (IGHD) due to GHRH or GHRH receptor mutations, combined deficiency of GH, prolactin, and TSH, or global deletion of GH receptors live longer than do their normal siblings. They also exhibit multiple features of delayed and/or slower aging, accompanied by extension of healthspan. The unexpected, remarkable longevity benefit of severe endocrine defects in these animals presumably represents evolutionarily conserved trade-offs among aging, growth, maturation, fecundity, and the underlying anabolic processes. Importantly, the negative association of GH signaling with longevity extends to other mammalian species, apparently including humans. Data obtained in humans with IGHD type 1B, owing to a mutation of the GHRH receptor gene, in the Itabaianinha County, Brazil, provide a unique opportunity to study the impact of severe reduction in GH signaling on age-related characteristics, health, and functionality. Individuals with IGHD are characterized by proportional short stature, doll facies, high-pitched voices, and central obesity. They have delayed puberty but are fertile and generally healthy. Moreover, these IGHD individuals are partially protected from cancer and some of the common effects of aging and can attain extreme longevity, 103 years of age in one case. We think that low, but detectable, residual GH secretion combined with life-long reduction of circulating IGF-1 and with some tissue levels of IGF-1 and/or IGF-2 preserved may account for the normal longevity and apparent extension of healthspan in these individuals.

Early Treatment with Growth Hormone (GH) and Rehabilitation Recovers Hearing in a Child with Cerebral Palsy

Neonatal hearing loss is one of the most common anomalies and is frequently associated with delivery problems. The effects of growth hormone (GH) on brain regeneration after an injury are well known. This paper looks at a male child diagnosed with cerebral palsy, psychomotor affectation, left spastic hemiparesis, and bilateral sensorineural hearing loss after fetal distress due to ruptured membranes before the delivery of more than 30 hours of evolution and several episodes of severe hypoglycemia. From 3.5 months of age, we treated him with GH (0.04 mg/kg/day), Melatonin (5 mg/day and 6 months later 10 mg/day) and rehabilitation, for a period of 14 months; at discharge, the child fully recovered all the disabilities produced by his cerebral palsy, including normal hearing; GMFM-88 increased from 7.84% to 48.23%; Battelle scores increased from 2 to 9 after 7 months of treatment, and to 30, 1 year after discharge. Most likely hearing loss was recovered due to the effect of GH on the production of hair cells from stem cells (only present in very young children) in the cochlear sensory epithelium. This is the first case of recovery of hearing loss in humans after GH administration. Moreover, GH administration is useful and safe for early treatment of cerebral palsy.

Hypothalamic abnormalities: Growth failure due to defects of the GHRH receptor

Several acquired or congenital hypothalamic abnormalities may cause growth failure (GF). We described two of these congenital abnormalities. First, a case of CHARGE syndrome, an epigenetic disorder mostly caused by heterozygous mutations in the gene encoding CHD7, a chromatin remodeling protein, causing several malformations, some life-threatening, with additional secondary hypothalamus-hypophyseal dysfunction, including GF. Second, a cohort of individuals with genetic isolated severe GH deficiency (IGHD), due to a homozygous mutation in the GH-releasing hormone (GHRH) receptor gene described in Itabaianinha County, in northeast Brazil. In this IGHD, with marked reduction of serum concentrations of IGF-I, and an up regulation of IGF-II, GF is the principal finding in otherwise normal subjects, with normal quality of life and longevity. This IGHD may unveil the effects of GHRH, pituitary GH and IGF-I, IGF-II and local GH and growth factor on the size and function of body and several systems. For instance, anterior pituitary hypoplasia, and impairment of the non-REM sleep may be due to GHRH resistance. Proportionate short stature, doll facies, high-pitched pre-pubertal voice, and reduced muscle mass reflect the lack of the synergistic effect of pituitary GH and IGF-I in bones and muscles. Central adiposity may be due to a direct effect of the lack of GH. Brain, eyes and immune system may also involve IGF-II and local GH or growth factors. A concept of physiological hierarchy controlling body size and function by each component of the GH system may be drawn from this model.

The Role of Insulin-Like Growth Factor 1 in the Progression of Age-Related Hearing Loss

Aging is associated with impairment of sensorial functions and with the onset of neurodegenerative diseases. As pari passu circulating insulin-like growth factor 1 (IGF-1) bioavailability progressively decreases, we see a direct correlation with sensory impairment and cognitive performance in older humans. Age-related sensory loss is typically caused by the irreversible death of highly differentiated neurons and sensory receptor cells. Among sensory deficits, age-related hearing loss (ARHL), also named presbycusis, affects one third of the population over 65 years of age and is a major factor in the progression of cognitive problems in the elderly. The genetic and molecular bases of ARHL are largely unknown and only a few genes related to susceptibility to oxidative stress, excitotoxicity, and cell death have been identified. IGF-1 is known to be a neuroprotective agent that maintains cellular metabolism, activates growth, proliferation and differentiation, and limits cell death. Inborn IGF-1 deficiency leads to profound sensorineural hearing loss both in humans and mice. IGF-1 haploinsufficiency has also been shown to correlate with ARHL. There is not much information available on the effect of IGF-1 deficiency on other human sensory systems, but experimental models show a long-term impact on the retina. A secondary action of IGF-1 is the control of oxidative stress and inflammation, thus helping to resolve damage situations, acute or made chronic by aging. Here we will review the primary actions of IGF-1 in the auditory system and the underlying molecular mechanisms.

Hearing loss in children with growth hormone deficiency

OBJECTIVE

Although insulin-like growth factor 1 (IGF-1) has been shown to be important for inner-ear development in animal models, little is known about the otologic and audiologic findings of children with growth hormone deficiency (GHD). The goal of this study is to evaluate the prevalence, type, and severity of hearing impairment in children with GHD.

METHODS

Audiologic, otologic, and demographic data were recorded for children with a diagnosis of GHD in the AudGen database. Data for each patient were selected based on the first encounter with available complete audiometric data or the first encounter with a type of hearing loss documented. The patients were then stratified by type and severity of hearing loss, and otologic issues were documented. A separate cohort comprised of children with GHD without hearing loss was compared as a control.

RESULTS

209 children with GHD met inclusion criteria. 173 (83%) of these patients had hearing loss. 79% of losses were bilateral and 21% were unilateral (309 total ears with hearing loss). 293 of the 309 ears with hearing loss had audiograms with ear-specific thresholds; 47 had conductive, 24 had sensorineural, 65 had mixed and 157 had undefined hearing loss with incomplete audiograms. Pure-tone averages (PTA) were higher among patients with mixed hearing loss compared to patients with all other loss types.

CONCLUSION

Hearing loss is prevalent in children with GHD with a predisposition to be bilateral. These findings suggest the need for increased awareness and routine hearing screening for patients with GHD. Further studies may elucidate the etiology of the hearing impairment in children with GHD to better aid pediatricians, endocrinologists, otolaryngologists and audiologists when assessing and managing these children.

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.

Misophonia: A new mental disorder?

Misophonia, a phenomenon first described in the audiology literature, is characterized by intense emotional reactions (e.g., anger, rage, anxiety, disgust) in response to highly specific sounds, particularly sounds of human origin such as oral or nasal noises made by other people (e.g., chewing, sniffing, slurping, lip smacking). Misophonia is not listed in any of the contemporary psychiatric classification systems. Some investigators have argued that misophonia should be regarded as a new mental disorder, falling within the spectrum of obsessive-compulsive related disorders. Other researchers have disputed this claim. The purpose of this article is to critically examine the proposition that misophonia should be classified as a new mental disorder. The clinical and research literature on misophonia was examined and considered in the context of the broader literature on what constitutes a mental disorder. There have been growing concerns that diagnostic systems such as DSM-5 tend to over-pathologize ordinary quirks and eccentricities. Accordingly, solid evidence is required for proposing a new psychiatric disorder. The available evidence suggests that (a) misophonia meets many of the general criteria for a mental disorder and has some evidence of clinical utility as a diagnostic construct, but (b) the nature and boundaries of the syndrome are unclear; for example, in some cases misophonia might be simply one feature of a broader pattern of sensory intolerance, and (c) considerably more research is required, particularly work concerning diagnostic validity, before misophonia, defined as either as a disorder or as a key feature of some broader syndrome of sensory intolerance, should be considered as a diagnostic construct in the psychiatric nomenclature. A research roadmap is proposed for the systematic evaluation as to whether misophonia should be considered for future editions of DSM or ICD.

Endocrine Glands and Hearing: Auditory Manifestations of Various Endocrine and Metabolic Conditions

The aetiology of hearing loss in humans is multifactorial. Besides genetic, environmental and infectious causes, several endocrine and metabolic abnormalities are associated with varying degrees of hearing impairment. The pattern of hearing loss may be conductive, sensori-neural or mixed. The neurophysiology of hearing as well as the anatomical structure of the auditory system may be influenced by changes in the hormonal and metabolic milieu. Optimal management of these conditions requires the integrated efforts of the otolaryngologist and the endocrinologist. The presence of hearing loss especially in the young age group should prompt the clinician to explore the possibility of an associated endocrine or metabolic disorder for timely referral and early initiation of treatment.

Voice Formants in Individuals With Congenital, Isolated, Lifetime Growth Hormone Deficiency

OBJECTIVE

To analyze the voice formants (F1, F2, F3, and F4 in Hz) of seven oral vowels, in Brazilian Portuguese, [a, ε, e, i, ɔ, o, and u] in adult individuals with congenital lifetime untreated isolated growth hormone deficiency (IGHD).

STUDY DESIGN

This is a cross-sectional study.

METHODS

Acoustic analysis of isolated vowels was performed in 33 individuals with IGHD, age 44.5 (17.6) years (16 women), and 29 controls, age 51.1 (17.6) years (15 women).

RESULTS

Compared with controls, IGHD men showed higher values of F3 [i, e, and ε], P = 0.006, P = 0.022, and P = 0.006, respectively and F4 [i], P = 0.001 and lower values of F2 [u], P = 0.034; IGHD women presented higher values of F1 [i and e] P = 0.029 and P = 0.036; F2 [ɔ] P = 0.006; F4 [ɔ] P = 0.031 and lower values of F2 [i] P = 0.004. IGHD abolished most of the gender differences in formant frequencies present in controls.

CONCLUSIONS

Congenital, severe IGHD results in higher values of most formant frequencies, suggesting smaller oral and pharyngeal cavities. In addition, it causes a reduction in the effect of gender on the structure of the formants, maintaining a prepubertal acoustic prediction.