Utility of serum IGF-1 for diagnosis of growth hormone deficiency following traumatic brain injury and sport-related concussion

The vasoprotective role of IGF-1 signaling in the cerebral microcirculation: prevention of cerebral microhemorrhages in aging

Aging is closely associated with various cerebrovascular pathologies that significantly impact brain function, with cerebral small vessel disease (CSVD) being a major contributor to cognitive decline in the elderly. Consequences of CSVD include cerebral microhemorrhages (CMH), which are small intracerebral bleeds resulting from the rupture of microvessels. CMHs are prevalent in aging populations, affecting approximately 50% of individuals over 80, and are linked to increased risks of vascular cognitive impairment and dementia (VCID). Hypertension is a primary risk factor for CMHs. Vascular smooth muscle cells (VSMCs) adapt to hypertension by undergoing hypertrophy and producing extracellular matrix (ECM) components, which reinforce vessel walls. Myogenic autoregulation, which involves pressure-induced constriction, helps prevent excessive pressure from damaging the vulnerable microvasculature. However, aging impairs these adaptive mechanisms, weakening vessel walls and increasing susceptibility to damage. Insulin-like Growth Factor 1 (IGF-1) is crucial for vascular health, promoting VSMC hypertrophy, ECM production, and maintaining normal myogenic protection. IGF-1 also prevents microvascular senescence, reduces reactive oxygen species (ROS) production, and regulates matrix metalloproteinase (MMP) activity, which is vital for ECM remodeling and stabilization. IGF-1 deficiency, common in aging, compromises these protective mechanisms, increasing the risk of CMHs. This review explores the vasoprotective role of IGF-1 signaling in the cerebral microcirculation and its implications for preventing hypertension-induced CMHs in aging. Understanding and addressing the decline in IGF-1 signaling with age are crucial for maintaining cerebrovascular health and preventing hypertension-related vascular injuries in the aging population.

A 2024 Update on Growth Hormone Deficiency Syndrome in Adults: From Guidelines to Real Life

Background: Adult growth hormone deficiency (GHD) has been recognized since the late 1980s. The clinical manifestations of adult GHD are often nonspecific, and diagnosis relies on GH stimulation tests, which are intricate, costly, time-consuming, and may carry the risk of adverse effects. Diagnosis is further complicated by factors like age, sex, and BMI, which affect GH response during testing. Therefore, GH replacement therapy remains challenging, requiring careful individualized evaluation of risks and benefits. The aim of this review is to provide an update on diagnosing and treating adult GHD, addressing current limitations and challenges based on recent studies. Methods: We conducted a comprehensive review of the literature regarding the diagnosis and management of adult GHD by searching PubMed and EMBASE. Only articles in English were included, and searches were conducted up to August 2024. Results: A review of guidelines and literature up to 2024 highlights the significant heterogeneity in the data and reveals various protocols for managing GHD, covering both diagnostic and therapeutic approaches. Conclusions: Despite diagnostic and treatment advances, managing adult GHD remains challenging due to variable presentation and the need for personalized GH therapy. Future efforts should aim to improve and standardize diagnostic and treatment protocols.

Pituitary dysfunction following mild traumatic brain injury in female athletes

Objective

Pituitary dysfunction following mild traumatic brain injury can have serious physical and psychological consequences, making correct diagnosis and treatment essential. To the best of our knowledge, this study is the first to study the prevalence of pituitary dysfunction following mild traumatic brain injury in an all-female population following detailed endocrinological work-up after screening for pituitary dysfunction in female athletes.

Design

This is a retrospective cohort study.

Methods

Hormone screening blood tests, including serum blood values for thyroid-stimulating hormone, free thyroxin, insulin-like growth factor 1, prolactin, cortisol, follicle-stimulating hormone, luteinizing hormone, estrogen and progesterone, were taken in 133 female athletes. Results were repeatedly outside the reference value in 88 women necessitating further endocrinological evaluation. Two of those were lost to follow-up, and further endocrinological evaluation was performed in 86 participants.

Results

Six women (4.6%, n = 131) were diagnosed with hypopituitarism, four (3.1%) with central hypothyroidism and two with growth hormone deficiency (1.5%). Ten women (7.6%) had hyperprolactinemia, and four (3.1%) of them had prolactinoma. Medical treatment was initiated in 13 (9.9%) women. Significant prognostic factors were not found.

Conclusions

As 12.2% of female athletes with a history of mild traumatic brain injury had pituitary dysfunction (hypopituitarism 4.6%, hyperprolactinemia 7.6%), we conclude that pituitary dysfunction is an important consideration in post-concussion care. Hyperprolactinemia in the absence of prolactinoma may represent pituitary or hypothalamic injury following mild traumatic brain injury.

Significance statement

Mild traumatic brain injury (mTBI) has become a growing public health concern as 50 million people worldwide sustain a traumatic brain injury annually, with mTBI being the most common (70-90%). As studies on mTBI have focused on mostly male populations this study aims to explore pituitary dysfunction (PD) in female athletes following mTBI. To the best of our knowledge, it is the first all-female study on PD following mTBI. The study found that 12.2% of the participating women had PD after mTBI. Six (4.6%) had hypopituitarism and ten (7.6%) had hyperprolactinemia. These findings suggest that PD following mTBI is an important consideration that endocrinologists and other medical staff working with athletes need to be aware of.

Neuroendocrine Disruptions Following Head Injury

PURPOSE OF REVIEW

This article reviews hypopituitarism after TBI, the importance of pituitary hormones, and related controversies, concluding with a suggested patient approach.

RECENT FINDINGS

While earlier studies focused on increased pituitary deficiencies after moderate-severe TBI, recent studies have focused on deficiencies after mild TBI. There has been increasing focus on the role of growth hormone after injury; growth hormone is the most frequent reported deficiency at 1 year post-TBI, and an area with unresolved questions. While more research is needed to quantify the risk of deficiencies in special populations, and establish the natural history, increasing data indicate an increase in hypopituitarism after other acquired brain injuries; the potential role of pituitary hormone deficiencies after stroke and after COVID-19 infection is an area of active inquiry. Given the negative health effects of untreated hypopituitarism and the opportunity to intervene via hormone replacement, it is important to recognize the role of pituitary hormone deficiencies after TBI.

Growth Hormone Deficiency following Traumatic Brain Injury in Pediatric and Adolescent Patients: Presentation, Treatment, and Challenges of Transitioning from Pediatric to Adult Services

Traumatic brain injury (TBI) is increasingly recognized, with an incidence of approximately 110 per 100,000 in pediatric populations and 618 per 100,000 in adolescent and adult populations. TBI often leads to cognitive, behavioral, and physical consequences, including endocrinopathies. Deficiencies in anterior pituitary hormones (e.g., adrenocorticotropic hormone, thyroid-stimulating hormone, gonadotropins, and growth hormone [GH]) can negatively impact health outcomes and quality of life post-TBI. This review focuses on GH deficiency (GHD), the most common post-TBI pituitary hormone deficiency. GHD is associated with abnormal body composition, lipid metabolism, bone mineral density, executive brain functions, behavior, and height outcomes in pediatric, adolescent, and transition-age patients. Despite its relatively frequent occurrence, post-TBI GHD has not been well studied in these patients; hence, diagnostic and treatment recommendations are limited. Here, we examine the occurrence and diagnosis of TBI, retrospectively analyze post-TBI hypopituitarism and GHD prevalence rates in pediatric and adolescent patients, and discuss appropriate GHD testing strategies and GH dosage recommendations for these patients. We place particular emphasis on the ways in which testing and dosage recommendations may change during the transition phase. We conclude with a review of the challenges faced by transition-age patients and how these may be addressed to improve access to adequate healthcare. Little information is currently available to help guide patients with TBI and GHD through the transition phase and there is a risk of interrupted care; therefore, a strength of this review is its emphasis on this critical period in a patient's healthcare journey.

Relationship between Anterior Pituitary Volume and IGF-1 Serum Levels in Soldiers with Mild Traumatic Brain Injury History

PURPOSE

A high mild traumatic brain injury (mTBI) incidence rate exists in military and sport. Hypopituitarism is an mTBI sequela; however, few studies have examined this phenomenon in those with an mTBI history. This cross-sectional study of Special Operations Forces combat soldiers aimed 1) to relate anterior pituitary gland volumes (actual and normalized) to insulin-like growth factor 1 (IGF-1) concentrations, 2) to examine the effect of mTBI history on anterior pituitary gland volumes (actual and normalized) and IGF-1 concentrations, and 3) to measure the odds of demonstrating lower anterior pituitary gland volumes (actual and normalized) or IGF-1 concentrations if self-reporting mTBI history.

METHODS

Anterior pituitary gland volumes were manually segmented from T1-weighted 3D brain MRI sequences; IGF-1 serum concentrations were quantified using commercial enzyme-linked immunosorbent assays. Correlations and linear regression were used to determine the association between IGF-1 serum concentration and anterior pituitary gland volume (n = 74). Independent samples t-tests were used to compare outcomes between mTBI groups and logistic regression models were fit to test the odds of demonstrating IGF-1 concentration or anterior pituitary volume less than sample median based on mTBI group (n = 54).

RESULTS

A significant linear relationship between the subjects' anterior pituitary gland volumes and IGF-1 concentrations (r72 = 0.35, P = 0.002) was observed. Soldiers with mTBI history had lower IGF-1 concentrations (P < 0.001) and lower anterior pituitary gland volumes (P = 0.037) and were at greater odds for IGF-1 serum concentrations less than the sample median (odds ratio = 5.73; 95% confidence interval = 1.77-18.55).

CONCLUSIONS

Anterior pituitary gland volume was associated with IGF-1 serum concentrations. Mild TBI history may be adversely associated with anterior pituitary gland volumes and IGF-1 concentrations. Longitudinal IGF-1 and anterior pituitary gland monitoring may be indicated in those who report one or more mTBI.

Relation of Mild Traumatic Brain Injury history to abnormalities on a preliminary Neuroendocrine screen; A multicenter LIMBIC-CENC analysis

PRIMARY OBJECTIVES

Determine if an abnormal preliminary neuroendocrine disorder (NED) blood test screen is associated with mild TBI (mTBI) history or post-concussiveclinical features.

RESEARCH DESIGN

Observational.

METHODS

Among 1,520 participants with military combatexposure, we measured randomly timed serum levels of insulin-likegrowth factor-1, thyroid stimulating hormone (TSH), and total testosterone as a preliminary NED screen. Using multivariable models, we analyzed relation of screen results in mTBI group membership and post-concussiveclinical features (fatigue, depression, cognitive symptoms, executive function, processing speed).

RESULTS

None of the mTBI positive groups, including repetitive (≥3 mTBI) and blast-related,differed from the non-TBIcontrols on rates of abnormal lab screen or rates of growth hormone deficiency (GHD), hypothyroidism or male hypogonadism in treatment records. Lab screen findings were also not associated with any clinical feature.

CONCLUSIONS

This study shows no evidence that remote mTBI(s) or implicated post-concussiveclinical features are linked to GHD, hypothyroidism or male hypogonadism. Large case-controlstudies incorporating more definitive neuroendocrine disorder NED testing (TSH plus thyroxine, early morning testosterone, LH, FSH, prolactin and GH provocative testing) are needed to determine whether mTBI(s) alone elevate one's risk for chronic NED and how best to select patients for comprehensive testing.

Growth hormone deficiency testing and treatment following mild traumatic brain injury

Pituitary dysfunction, specifically growth hormone (GH) deficiency, can occur following traumatic brain injury. Our objective was to characterize the prevalence of GH deficiency (GHD) testing and response to recombinant human GH (rhGH) treatment in adults with persistent symptoms following mild traumatic brain injury (mTBI) referred for assessment of pituitary dysfunction. A retrospective chart review was conducted of patients seen at an outpatient brain injury clinic with a diagnosis of mTBI and persistent post-concussive symptoms who were referred to endocrinology. Clinical assessments of symptoms were collected. Investigations and results of GHD were collected, including initiation of rhGH treatment and treatment response. Of the 253 patients seen in both brain injury and endocrinology clinics, 97 with mTBI were referred for investigation of pituitary dysfunction and 73 (75%) had dynamic testing for assessment of GHD. Of the 26 individuals diagnosed with GHD, 23 (88%) started rhGH. GH therapy was inconsistently offered based on interpretation of GH dynamic testing results. Of those who started rhGH, 18 (78%) had a useful treatment response. This study suggests that clinical management of these patients is varied, highlighting a need for clear guidelines for the diagnosis and management of GHD following mTBI.

Experience of a Pituitary Clinic for US Military Veterans With Traumatic Brain Injury

Context

Traumatic brain injury (TBI) is considered the "signature" injury of veterans returning from wartime conflicts in Iraq and Afghanistan. While moderate/severe TBI is associated with pituitary dysfunction, this association has not been well established in the military setting and in mild TBI (mTBI). Screening for pituitary dysfunction resulting from TBI in veteran populations is inconsistent across Veterans Affairs (VA) institutions, and such dysfunction often goes unrecognized and untreated.

Objective

This work aims to report the experience of a pituitary clinic in screening for and diagnosis of pituitary dysfunction.

Methods

A retrospective analysis was conducted in a US tertiary care center of veterans referred to the VA Puget Sound Healthcare System pituitary clinic with a history of TBI at least 12 months prior. Main outcome measures included demographics, medical history, symptom burden, baseline hormonal evaluation, brain imaging, and provocative testing for adrenal insufficiency (AI) and adult-onset growth hormone deficiency (AGHD).

Results

Fatigue, cognitive/memory problems, insomnia, and posttraumatic stress disorder were reported in at least two-thirds of the 58 patients evaluated. Twenty-two (37.9%) were diagnosed with at least one pituitary hormone deficiency, including 13 (22.4%) AI, 12 (20.7%) AGHD, 2 (3.4%) secondary hypogonadism, and 5 (8.6%) hyperprolactinemia diagnoses; there were no cases of thyrotropin deficiency.

Conclusion

A high prevalence of chronic AI and AGHD was observed among veterans with TBI. Prospective, larger studies are needed to confirm these results and determine the effects of hormone replacement on long-term outcomes in this setting.

Traumatic brain injury-induced cerebral microbleeds in the elderly

Traumatic brain injury (TBI) was shown to lead to the development of cerebral microbleeds (CMBs), which are associated with long term cognitive decline and gait disturbances in patients. The elderly is one of the most vulnerable parts of the population to suffer TBI. Importantly, ageing is known to exacerbate microvascular fragility and to promote the formation of CMBs. In this overview, the effect of ageing is discussed on the development and characteristics of TBI-related CMBs, with special emphasis on CMBs associated with mild TBI. Four cases of TBI-related CMBs are described to illustrate the concept that ageing exacerbates the deleterious microvascular effects of TBI and that similar brain trauma may induce more CMBs in old patients than in young ones. Recommendations are made for future prospective studies to establish the mechanistic effects of ageing on the formation of CMBs after TBI, and to determine long-term consequences of CMBs on clinically relevant outcome measures including cognitive performance, gait and balance function.

Pituitary dysfunction after traumatic brain injury: prevalence and screening strategies

INTRODUCTION

Pituitary gland is vulnerable to traumatic brain injury (TBI). As a result a series of neuroendocrine changes appear after head injury; in many occasions they reverse with time, while occasionally new late onset changes may develop.

AREAS COVERED

In this review, we focus on the prevalence of anterior and posterior pituitary hormonal changes in the acute and chronic post-TBI period in both children and adults. Moreover, we present evidence supporting the need for evaluating pituitary function along with the current suggestions for the most appropriate screening strategies. We attempted to identify all published literature and we conducted an online search of PubMed, from January 1970 to June 2020.

EXPERT OPINION

Adrenal insufficiency and water metabolism disorders are medical emergencies and should be promptly recognized. Awareness for long-term hormonal derangements is necessary, as they may lead to a series of chronic health issues and compromise quality of life. There is a need for well-designed prospective long-term studies that will estimate pituitary function during the acute and chronic phase after head injury.

Examining the Effects of Anabolic-Androgenic Steroids on Repetitive Mild Traumatic Brain Injury (RmTBI) Outcomes in Adolescent Rats

Background: Repetitive mild traumatic brain injury (RmTBI) is increasingly common in adolescents. Anabolic–androgenic steroid (AAS) consumption among younger professional athletes is a significant risk factor for impaired neurodevelopment. Given the increased rates and overlapping symptomology of RmTBI and AAS use, we sought to investigate the behavioural and neuropathological outcomes associated with the AAS Metandienone (Met) and RmTBI on rats. Methods: Rats received either Met or placebo and were then administered RmTBIs or sham injuries, followed by a behavioural test battery. Post-mortem MRI was conducted to examine markers of brain integrity and qRT-PCR assessed mRNA expression of markers for neurodevelopment, neuroinflammation, stress responses, and repair processes. Results: Although AAS and RmTBI did not produce cumulative deficits, AAS use was associated with detrimental outcomes including changes to depression, aggression, and memory; prefrontal cortex (PFC) atrophy and amygdala (AMYG) enlargement; damaged white matter integrity in the corpus callosum; and altered mRNA expression in the PFC and AMYG. RmTBI affected general activity and contributed to PFC atrophy. Conclusions: Findings corroborate previous results indicating that RmTBI negatively impacts neurodevelopment but also demonstrates that AAS results in significant neuropathological insult to the developing brain.

Adapting the Dynamic, Recursive Model of Sport Injury to Concussion: An Individualized Approach to Concussion Prevention, Detection, Assessment, and Treatment

The risk factors of concussion may be categorized as intrinsic (internal factors specific to the individual) or extrinsic (external factors related to the environment or sport). Identifying these factors is part of an individualized, patient-centered approach to prevention, assessment, and management of concussion. In most cases, the symptoms of concussion resolve in the initial few days following the injury, and a strategy involving a gradual return to sport and school is recommended. When symptoms persist for longer than 7 to 10 days, a multifaceted interdisciplinary assessment to guide treatment is recommended. This article applies the dynamic, recursive model of sport injury to sport-related concussion and summarizes the process of individualized assessment and management following concussion in athletes of all ages, with a focus on physical rehabilitation. J Orthop Sports Phys Ther 2019;49(11):799-810. doi:10.2519/jospt.2019.8926.

Pituitary dysfunction due to sports-related traumatic brain injury

PURPOSE

After traumatic brain injury was accepted as an important etiologic factor of pituitary dysfunction (PD), awareness of risk of developing PD following sports-related traumatic brain injury (SR-TBI) has also increased. However there are not many studies investigating PD following SR-TBIs yet. We aimed to summarize the data reported so far and to discuss screening algorithms and treatment strategies.

METHODS

Recent data on pituitary dysfunction after SR-TBIs is reviewed on basis of diagnosis, clinical perspectives, therapy, screening and possible prevention strategies.

RESULTS

Pituitary dysfunction is reported to occur in a range of 15-46.6% following SR-TBIs depending on the study design. Growth hormone is the most commonly reported pituitary hormone deficiency in athletes. Pituitary hormone deficiencies may occur during acute phase after head trauma, may improve with time or new deficiencies may develop during follow-up. Central adrenal insufficiency is the only and most critical impairment that requires urgent detection and replacement during acute phase. Decision on replacement of growth hormone and gonadal deficiencies should be individualized. Moreover these two hormones are abused by many athletes and a therapeutic use exemption from the league's drug policy may be required.

CONCLUSIONS

Even mild and forgotten SR-TBIs may cause PD that may have distressing consequences in some cases if remain undiagnosed. More studies are needed to elucidate epidemiology and pathophysiology of PD after SR-TBIs. Also studies to establish screening algorithms for PD as well as strategies for prevention of SR-TBIs are urgently required.