Antipituitary antibodies after traumatic brain injury: is head trauma-induced pituitary dysfunction associated with autoimmunity?

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY DISEASE STATE CLINICAL REVIEW: A NEUROENDOCRINE APPROACH TO PATIENTS WITH TRAUMATIC BRAIN INJURY

OBJECTIVE

Traumatic brain injury (TBI) is now recognized as a major public health concern in the United States and is associated with substantial morbidity and mortality in both children and adults. Several lines of evidence indicate that TBI-induced hypopituitarism is not infrequent in TBI survivors and may contribute to the burden of illness in this population. The goal of this article is to review the published data and propose an approach for the neuroendocrine evaluation and management of these patients.

METHODS

To identify pertinent articles, electronic literature searches were conducted using the following keywords: "traumatic brain injury," "pituitary," "hypopituitarism," "growth hormone deficiency," "hypogonadism," "hypoadrenalism," and "hypothyroidism." Relevant articles were identified and considered for inclusion in the present article.

RESULTS

TBI-induced hypopituitarism appears to be more common in patients with severe TBI. However, patients with mild TBI or those with repeated, sports-, or blast-related TBI are also at risk for hypopituitarism. Deficiencies of growth hormone and gonadotropins appear to be most common and have been associated with increased morbidity in this population. A systematic approach is advised in order to establish the presence of pituitary hormone deficiencies and implement appropriate replacement therapies.

CONCLUSION

The presence of traumatic hypopituitarism should be considered during the acute phase as well as during the rehabilitation phase of patients with TBI. All patients with moderate to severe TBI require evaluation of pituitary function. In addition, symptomatic patients with mild TBI and impaired quality of life are at risk for hypopituitarism and should be offered neuroendocrine testing.

Clinical and diagnostic approach to patients with hypopituitarism due to traumatic brain injury (TBI), subarachnoid hemorrhage (SAH), and ischemic stroke (IS)

The hypothalamic-pituitary dysfunction attributable to traumatic brain injury (TBI), aneurysmal subarachnoid hemorrhage (SAH), and ischemic stroke (IS) has been lately highlighted. The diagnosis of TBI-induced-hypopituitarism, defined as a deficient secretion of one or more pituitary hormones, is made similarly to the diagnosis of classical hypopituitarism because of hypothalamic/pituitary diseases. Hypopituitarism is believed to contribute to TBI-associated morbidity and to functional and cognitive final outcome, and quality-of-life impairment. Each pituitary hormone must be tested separately, since there is a variable pattern of hormone deficiency among patients with TBI-induced-hypopituitarism. Similarly, the SAH and IS may lead to pituitary dysfunction although the literature in this field is limited. The drive to diagnose hypopituitarism is the suspect that the secretion of one/more pituitary hormone may be subnormal. This suspicion can be based upon the knowledge that the patient has an appropriate clinical context in which hypopituitarism can be present, or a symptom known as caused by hypopituitarism. Hypopituitarism should be diagnosed as a combination of low peripheral and inappropriately normal/low pituitary hormones although their basal evaluation may be not distinctive due to pulsatile, circadian, or situational secretion of some hormones. Evaluation of the somatotroph and corticotroph axes require dynamic stimulation test (ITT for both axes, GHRH + arginine test for somatotroph axis) in order to clearly separate normal from deficient responses.

Isolated Adrenocorticotropic Hormone or Thyrotropin Deficiency Following Mild Traumatic Brain Injury: Three Cases with Long-Term Follow-Up

Few studies have examined the clinical features and long-term outcomes of isolated pituitary hormone deficiencies after traumatic brain injury (TBI). Such deficiencies typically present at time intervals after TBI, especially after mild injuries such as concussions, which makes their diagnosis difficult without careful history taking. It is necessary to improve diagnosis and prevent life threatening or morbid conditions such as those that may occur in deficiencies of adrenocorticotropic hormone (ACTH) or thyroid-stimulating hormone (as known as thyrotropin, TSH), the two most important pituitary hormones in hypopituitarism treatment. Here, we report two cases of isolated ACTH deficiency and one case of isolated TSH deficiency. These patients presented at different time points after concussion and underwent long-term follow-ups.

Pituitary macroadenoma with persisting dense lymphocytic infiltration in a young male patient

Context: Lymphocytic anterior hypophysitis in association with a pituitary adenoma was reported previously. In rare instance, inflammatory infiltration was confined to adenoma tissue itself, excluding anterior pituitary. Case: The patient – a 27-year-old male – presented with visual field defect. Further examination revealed a pituitary mass with suprasellar extension. Hormonal evaluation indicated mild hyperprolactinemia (42 ng/ml, normal < 19). After transsphenoidal resection, a pituitary adenoma showing cytoplasmic immunoreactivity to prolactin was identified. Dense and diffuse lymphocytic infiltration was seen within the tumor. At 15th month, a second transsphenoidal operation was necessary because of rapid development of visual compromise and headache. Excised surgical specimen consistent with previously resected adenoma showed diffuse lymphocytic infiltration composed of B and T cells within the adenoma tissue again. Conclusion: Presence of dense, hypophysitis-like lymphocytic infiltration within pituitary adenoma tissue obtained by two consecutive operations may reflect an host-mediated immune reaction to tumor. This rare finding could be challenging in terms of differential diagnosis and follow-up course.

Circulating MicroRNAs as Potential Biomarkers for Traumatic Brain Injury-Induced Hypopituitarism

Traumatic brain injury (TBI), a worldwide public health problem, has recently been recognized as a common cause of pituitary dysfunction. Circulating microRNAs (miRNAs) present in the sera are characteristically altered in many pathological conditions and have been used as diagnostic markers for specific diseases. It is with this goal that we planned to study miRNA expression in patients with TBI-induced hypopituitarism. Thirty-eight patients (27 male, 11 female; mean age, 43 ± 18 years) who had been admitted to the neurosurgery intensive care unit due to TBI were included in the acute phase of the study. In the chronic phase, miRNA expression profile blood samples were drawn from 25 patients who had suffered TBI 5 years ago. In the acute phase (on Days 1, 7, and 28), a substantial amount of patients (26%, 40%, and 53%; respectively) had hypopituitarism (acute adrenocorticotropic hormone deficiency). In the chronic phase eight of 25 patients (32%) had TBI-induced-hypopituitarism. Forty-seven age-gender-similar healthy controls (25 male, 22 female, mean age: 41 ± 14 years) were included in the study. In order to identify potential candidate miRNA/miRNAs whose levels had been altered in response to TBI-induced hypopituitarism, 740 miRNA expression analyses were performed in the sera of TBI patients by high throughput real-time polymerase chain reaction. Statistical analyses showed that miRNA-126-3p (miR-126-3p) and miRNA-3610 (miR-3610) were detected in the sera of patients who developed hypopituitarism on the 1st, 7th, and 28th days, and in the 5th year following TBI. In addition, miRNA-3907 showed statistically significant and constant dynamic changes on the 1st, 7th, and 28th days, and in the 5th year in the patients with TBI. Our results indicated that altered expression of miR-126-3p and miR-3610 may play an important role in the development of TBI-induced hypopituitarism.

Plasma Anti-Glial Fibrillary Acidic Protein Autoantibody Levels during the Acute and Chronic Phases of Traumatic Brain Injury: A Transforming Research and Clinical Knowledge in Traumatic Brain Injury Pilot Study

We described recently a subacute serum autoantibody response toward glial fibrillary acidic protein (GFAP) and its breakdown products 5-10 days after severe traumatic brain injury (TBI). Here, we expanded our anti-GFAP autoantibody (AutoAb[GFAP]) investigation to the multicenter observational study Transforming Research and Clinical Knowledge in TBI Pilot (TRACK-TBI Pilot) to cover the full spectrum of TBI (Glasgow Coma Scale 3-15) by using acute (<24 h) plasma samples from 196 patients with acute TBI admitted to three Level I trauma centers, and a second cohort of 21 participants with chronic TBI admitted to inpatient TBI rehabilitation. We find that acute patients self-reporting previous TBI with loss of consciousness (LOC) (n = 43) had higher day 1 AutoAb[GFAP] (mean ± standard error: 9.11 ± 1.42; n = 43) than healthy controls (2.90 ± 0.92; n = 16; p = 0.032) and acute patients reporting no previous TBI (2.97 ± 0.37; n = 106; p < 0.001), but not acute patients reporting previous TBI without LOC (8.01 ± 1.80; n = 47; p = 0.906). These data suggest that while exposure to TBI may trigger the AutoAb[GFAP] response, circulating antibodies are elevated specifically in acute TBI patients with a history of TBI. AutoAb[GFAP] levels for participants with chronic TBI (average post-TBI time 176 days or 6.21 months) were also significantly higher (15.08 ± 2.82; n = 21) than healthy controls (p < 0.001). These data suggest a persistent upregulation of the autoimmune response to specific brain antigen(s) in the subacute to chronic phase after TBI, as well as after repeated TBI insults. Hence, AutoAb[GFAP] may be a sensitive assay to study the dynamic interactions between post-injury brain and patient-specific autoimmune responses across acute and chronic settings after TBI.

The Development of Neuroendocrine Disturbances over Time: Longitudinal Findings in Patients after Traumatic Brain Injury and Subarachnoid Hemorrhage

Previous reports suggest that neuroendocrine disturbances in patients with traumatic brain injury (TBI) or aneurysmal subarachnoid hemorrhage (SAH) may still develop or resolve months or even years after the trauma. We investigated a cohort of n = 168 patients (81 patients after TBI and 87 patients after SAH) in whom hormone levels had been determined at various time points to assess the course and pattern of hormonal insufficiencies. Data were analyzed using three different criteria: (1) patients with lowered basal laboratory values; (2) patients with lowered basal laboratory values or the need for hormone replacement therapy; (3) diagnosis of the treating physician. The first hormonal assessment after a median time of three months after the injury showed lowered hormone laboratory test results in 35% of cases. Lowered testosterone (23.1% of male patients), lowered estradiol (14.3% of female patients) and lowered insulin-like growth factor I (IGF-I) values (12.1%) were most common. Using Criterion 2, a higher prevalence rate of 55.6% of cases was determined, which correlated well with the prevalence rate of 54% of cases using the physicians’ diagnosis as the criterion. Intraindividual changes (new onset insufficiency or recovery) were predominantly observed for the somatotropic axis (12.5%), the gonadotropic axis in women (11.1%) and the corticotropic axis (10.6%). Patients after TBI showed more often lowered IGF-I values at first testing, but normal values at follow-up (p < 0.0004). In general, most patients remained stable. Stable hormone results at follow-up were obtained in 78% (free thyroxine (fT4) values) to 94.6% (prolactin values).

GH and Pituitary Hormone Alterations After Traumatic Brain Injury

Traumatic brain injury (TBI) is a crucially important public health problem around the world, which gives rise to increased mortality and is the leading cause of physical and psychological disability in young adults, in particular. Pituitary dysfunction due to TBI was first described 95 years ago. However, until recently, only a few papers have been published in the literature and for this reason, TBI-induced hypopituitarism has been neglected for a long time. Recent studies have revealed that TBI is one of the leading causes of hypopituitarism. TBI which causes hypopituitarism may be characterized by a single head injury such as from a traffic accident or by chronic repetitive head trauma as seen in combative sports including boxing, kickboxing, and football. Vascular damage, hypoxic insult, direct trauma, genetic predisposition, autoimmunity, and neuroinflammatory changes may have a role in the development of hypopituitarism after TBI. Because of the exceptional structure of the hypothalamo-pituitary vasculature and the special anatomic location of anterior pituitary cells, GH is the most commonly lost hormone after TBI, and the frequency of isolated GHD is considerably high. TBI-induced pituitary dysfunction remains undiagnosed and therefore untreated in most patients because of the nonspecific and subtle clinical manifestations of hypopituitarism. Treatment of TBI-induced hypopituitarism depends on the deficient anterior pituitary hormones. GH replacement therapy has some beneficial effects on metabolic parameters and neurocognitive dysfunction. Patients with TBI without neuroendocrine changes and those with TBI-induced hypopituitarism share the same clinical manifestations, such as attention deficits, impulsion impairment, depression, sleep abnormalities, and cognitive disorders. For this reason, TBI-induced hypopituitarism may be neglected in TBI victims and it would be expected that underlying hypopituitarism would aggravate the clinical picture of TBI itself. Therefore, the diagnosis and treatment of unrecognized hypopituitarism due to TBI are very important not only to decrease morbidity and mortality due to hypopituitarism but also to alleviate the chronic sequelae caused by TBI.

Pituitary and/or hypothalamic dysfunction following moderate to severe traumatic brain injury: Current perspectives

There is an increasing deliberation regarding hypopituitarism following traumatic brain injury (TBI) and recent data have suggested that pituitary dysfunction is very common among survivors of patients having moderate-severe TBI which may evolve or resolve over time. Due to high prevalence of pituitary dysfunction after moderate-severe TBI and its association with increased morbidity and poor recovery and the fact that it can be easily treated with hormone replacement, it has been suggested that early detection and treatment is necessary to prevent long-term neurological consequences. The cause of pituitary dysfunction after TBI is still not well understood, but evidence suggests few possible primary and secondary causes. Results of recent studies focusing on the incidence of hypopituitarism in the acute and chronic phases after TBI are varied in terms of severity and time of occurrence. Although the literature available does not show consistent values and there is difference in study parameters and diagnostic tests used, it is clear that pituitary dysfunction is very common after moderate to severe TBI and patients should be carefully monitored. The exact timing of development cannot be predicted but has suggested regular assessment of pituitary function up to 1 year after TBI. In this narrative review, we aim to explore the current evidence available regarding the incidence of pituitary dysfunction in acute and chronic phase post-TBI and recommendations for screening and follow-up in these patients. We will also focus light over areas in this field worthy of further investigation.

Update of Endocrine Dysfunction following Pediatric Traumatic Brain Injury

Traumatic brain injuries (TBI) are common occurrences in childhood, often resulting in long term, life altering consequences. Research into endocrine sequelae following injury has gained attention; however, there are few studies in children. This paper reviews the pathophysiology and current literature documenting risk for endocrine dysfunction in children suffering from TBI. Primary injury following TBI often results in disruption of the hypothalamic-pituitary-adrenal axis and antidiuretic hormone production and release, with implications for both acute management and survival. Secondary injuries, occurring hours to weeks after TBI, result in both temporary and permanent alterations in pituitary function. At five years after moderate to severe TBI, nearly 30% of children suffer from hypopituitarism. Growth hormone deficiency and disturbances in puberty are the most common; however, any part of the hypothalamic-pituitary axis can be affected. In addition, endocrine abnormalities can improve or worsen with time, having a significant impact on children’s quality of life both acutely and chronically. Since primary and secondary injuries from TBI commonly result in transient or permanent hypopituitarism, we conclude that survivors should undergo serial screening for possible endocrine disturbances. High indices of suspicion for life threatening endocrine deficiencies should be maintained during acute care. Additionally, survivors of TBI should undergo endocrine surveillance by 6–12 months after injury, and then yearly, to ensure early detection of deficiencies in hormonal production that can substantially influence growth, puberty and quality of life.

Hypopituitarism in Traumatic Brain Injury-A Critical Note

While hypopituitarism after traumatic brain injury (TBI) was previously considered rare, it is now thought to be a major cause of treatable morbidity among TBI survivors. Consequently, recommendations for assessment of pituitary function and replacement in TBI were recently introduced. Given the high incidence of TBI with more than 100 pr. 100,000 inhabitants, TBI would be by far the most common cause of hypopituitarism if the recently reported prevalence rates hold true. The disproportion between this proposed incidence and the occasional cases of post-TBI hypopituitarism in clinical practice justifies reflection as to whether hypopituitarism has been unrecognized in TBI patients or whether diagnostic testing designed for high risk populations such as patients with obvious pituitary pathology has overestimated the true risk and thereby the disease burden of hypopituitarism in TBI. The findings on mainly isolated deficiencies in TBI patients, and particularly isolated growth hormone (GH) deficiency, raise the question of the potential impact of methodological confounding, determined by variable test-retest reproducibility, appropriateness of cut-off values, importance of BMI stratified cut-offs, assay heterogeneity, pre-test probability of hypopituitarism and lack of proper individual laboratory controls as reference population. In this review, current recommendations are discussed in light of recent available evidence.

Impaired Pituitary Axes Following Traumatic Brain Injury

Pituitary dysfunction following traumatic brain injury (TBI) is significant and rarely considered by clinicians. This topic has received much more attention in the last decade. The incidence of post TBI anterior pituitary dysfunction is around 30% acutely, and declines to around 20% by one year. Growth hormone and gonadotrophic hormones are the most common deficiencies seen after traumatic brain injury, but also the most likely to spontaneously recover. The majority of deficiencies present within the first year, but extreme delayed presentation has been reported. Information on posterior pituitary dysfunction is less reliable ranging from 3%-40% incidence but prospective data suggests a rate around 5%. The mechanism, risk factors, natural history, and long-term effect of treatment are poorly defined in the literature and limited by a lack of standardization. Post TBI pituitary dysfunction is an entity to recognize with significant clinical relevance. Secondary hypoadrenalism, hypothyroidism and central diabetes insipidus should be treated acutely while deficiencies in growth and gonadotrophic hormones should be initially observed.

Pituitary dysfunction after traumatic brain injury: a clinical and pathophysiological approach

Traumatic brain injury (TBI) is a growing public health problem worldwide and is a leading cause of death and disability. The causes of TBI include motor vehicle accidents, which are the most common cause, falls, acts of violence, sports-related head traumas, and war accidents including blast-related brain injuries. Recently, pituitary dysfunction has also been described in boxers and kickboxers. Neuroendocrine dysfunction due to TBI was described for the first time in 1918. Only case reports and small case series were reported until 2000, but since then pituitary function in TBI victims has been investigated in more detail. The frequency of hypopituitarism after TBI varies widely among different studies (15-50% of the patients with TBI in most studies). The estimates of persistent hypopituitarism decrease to 12% if repeated testing is applied. GH is the most common hormone lost after TBI, followed by ACTH, gonadotropins (FSH and LH), and TSH. The underlying mechanisms responsible for pituitary dysfunction after TBI are not entirely clear; however, recent studies have shown that genetic predisposition and autoimmunity may have a role. Hypopituitarism after TBI may have a negative impact on the pace or degree of functional recovery and cognition. What is not clear is whether treatment of hypopituitarism has a beneficial effect on specific function. In this review, the current data related to anterior pituitary dysfunction after TBI in adult patients are updated, and guidelines for the diagnosis, follow-up strategies, and therapeutic approaches are reported.

Hypothalamic-Pituitary Autoimmunity and Traumatic Brain Injury

Background: Traumatic brain injury (TBI) is a leading cause of secondary hypopituitarism in children and adults, and is responsible for impaired quality of life, disabilities and compromised development. Alterations of pituitary function can occur at any time after the traumatic event, presenting in various ways and evolving during time, so they require appropriate screening for early detection and treatment. Although the exact pathophysiology is unknown, several mechanisms have been hypothesized, including hypothalamic-pituitary autoimmunity (HP-A). The aim of this study was to systematically review literature on the association between HP-A and TBI-induced hypopituitarism. Major pitfalls related to the HP-A investigation were also discussed. Methods: The PubMed database was searched with a string developed for this purpose, without temporal or language limits, for original articles assessing the association of HP-A and TBI-induced hypopituitarism. Results: Three articles from the same group met the inclusion criteria. Anti-pituitary and anti-hypothalamic antibodies were detected using indirect immunofluorescence in a significant number of patients with acute and chronic TBI. Elevated antibody titer was associated with an increased risk of persistent hypopituitarism, especially somatotroph and gonadotroph deficiency, while no correlations were found with clinical parameters. Conclusion: HPA seems to contribute to TBI-induced pituitary damage, although major methodological issues need to be overcome and larger studies are warranted to confirm these preliminary data.

Neuroendocrine Disturbances after Brain Damage: An Important and Often Undiagnosed Disorder

Traumatic brain injury (TBI) is a common and significant public health problem all over the world. Until recently, TBI has been recognized as an uncommon cause of hypopituitarism. The studies conducted during the last 15 years revealed that TBI is a serious cause of hypopituitarism. Although the underlying pathophysiology has not yet been fully clarified, new data indicate that genetic predisposition, autoimmunity and neuroinflammatory changes may play a role in the development of hypopituitarism. Combative sports, including boxing and kickboxing, both of which are characterized by chronic repetitive head trauma, have been shown as new causes of neuroendocrine abnormalities, mainly hypopituitarism, for the first time during the last 10 years. Most patients with TBI-induced pituitary dysfunction remain undiagnosed and untreated because of the non-specific and subtle clinical manifestations of hypopituitarism. Replacement of the deficient hormones, of which GH is the commonest hormone lost, may not only reverse the clinical manifestations and neurocognitive dysfunction, but may also help posttraumatic disabled patients resistant to classical treatment who have undiagnosed hypopituitarism and GH deficiency in particular. Therefore, early diagnosis, which depends on the awareness of TBI as a cause of neuroendocrine abnormalities among the medical community, is crucially important.

Hypopituitarism after traumatic brain injury

The prevalence of hypopituitarism after traumatic brain (TBI) injury is widely variable in the literature; a meta-analysis determined a pooled prevalence of anterior hypopituitarism of 27.5%. Growth hormone deficiency is the most prevalent hormone insufficiency after TBI; however, the prevalence of each type of pituitary deficiency is influenced by the assays used for diagnosis, severity of head trauma, and time of evaluation. Recent studies have demonstrated improvement in cognitive function and cognitive quality of life with substitution therapy in GH-deficient patients after TBI.

Minor and repetitive head injury

Traumatic brain injury (TBI) is the leading cause of death and disability in the young, active population and expected to be the third leading cause of death in the whole world until 2020. The disease is frequently referred to as the silent epidemic, and many authors highlight the "unmet medical need" associated with TBI.The term traumatically evoked brain injury covers a heterogeneous group ranging from mild/minor/minimal to severe/non-salvageable damages. Severe TBI has long been recognized to be a major socioeconomical health-care issue as saving young lives and sometimes entirely restituting health with a timely intervention can indeed be extremely cost efficient.Recently it has been recognized that mild or minor TBI should be considered similarly important because of the magnitude of the patient population affected. Other reasons behind this recognition are the association of mild head injury with transient cognitive disturbances as well as long-term sequelae primarily linked to repeat (sport-related) injuries.The incidence of TBI in developed countries can be as high as 2-300/100,000 inhabitants; however, if we consider the injury pyramid, it turns out that severe and moderate TBI represents only 25-30 % of all cases, while the overwhelming majority of TBI cases consists of mild head injury. On top of that, or at the base of the pyramid, are the cases that never show up at the ER - the unreported injuries.Special attention is turned to mild TBI as in recent military conflicts it is recognized as "signature injury."This chapter aims to summarize the most important features of mild and repetitive traumatic brain injury providing definitions, stratifications, and triage options while also focusing on contemporary knowledge gathered by imaging and biomarker research.Mild traumatic brain injury is an enigmatic lesion; the classification, significance, and its consequences are all far less defined and explored than in more severe forms of brain injury.Understanding the pathobiology and pathomechanisms may aid a more targeted approach in triage as well as selection of cases with possible late complications while also identifying the target patient population where preventive measures and therapeutic tools should be applied in an attempt to avoid secondary brain injury and late complications.

Evaluation of long-term pituitary functions in patients with severe ventricular arrhythmia: a pilot study

INTRODUCTION

Traumatic brain injury (TBI), subarachnoid hemorrhage (SAH), stroke and cerebrovascular disease (CVD) are identified as risk factors for hypopituitarism. Pituitary dysfunction after TBI, SAH, and CVD may present in the acute phase or later in the course of the event. Chronic hypopituitarism, particularly growth hormone (GH) deficiency is related to the increased cardiovascular morbidity and mortality. In patients with serious ventricular arrhythmias, who need cardiopulmonary resuscitation, brain tissue is exposed to short-term severe ischemia and hypoxia. However, there are no data in the literature regarding pituitary dysfunction after ventricular arrhythmias.

PATIENTS AND METHODS

Forty-four patients with ventricular arrhythmias [ventricular tachycardia (VT), ventricular fibrillation (VF)] (mean age, 55.6 ± 1.8 years; 37 men, 7 women) were included in the study. The patients were evaluated after mean period of 21.2 ± 0.8 months from VT-VF. Basal hormone levels, including serum free triiodothyronine (fT3), free thyroxine (fT4), TSH, ACTH, prolactin, FSH, LH, total testosterone, estradiol, IGF-1, and cortisol levels were measured in all patients. To assess (GH)-insulin like growth factor-1 (IGF-1) axis, glucagon stimulation test was performed and 1 µg ACTH stimulation test was used for assessing hypothalamic-pituitary-adrenal (HPA) axis.

RESULTS

The frequencies of GH, gonadotropin and TSH deficiency were 27.2, 9.0, 2.2%, respectively. Mean IGF-1 levels were lower in GH deficiency group, but it was not statistically significant.

CONCLUSION

The present preliminary study showed that ventricular arrhythmias may result in hypopituitarism, particularly in growth hormone deficiency. Unrecognized hypopituitarism may be responsible for some of the cardiovascular problems at least in some patients.

Use of serum pituitary antibodies to improve the diagnosis of hypophysitis

Lymphocytic hypophysitis is characterized by an extensive infiltration of lymphocytic cells. Pituitary biopsy is the gold diagnostic standard for lymphocytic hypophysitis but the disease occurs with moderate or without pituitary enlargement. The role of antipituitary antibodies (APA) in autoimmune hypophysitis is still discussed due to various methodological difficulties. Indirect immunofluorescence, a widely employed method to detect APA at this time produces highly variable results due to the use of human or animal pituitary substrates. For many years the authors have conducted a re-evaluation of APA by immunofluorescence in patients with other autoimmune diseases and in patients with apparently idiopathic hypopituitarism, using pituitary from young baboons as substrate but considering a predetermined cut-off of the titer and immunofluorescence pattern. This procedure allowed us to find out those with autoimmune pituitary impairment and to foresee the kind of future hypopituitarism in those with pituitary function still normal. Moreover, in APA positive patients, the use of a second step of a double immunofluorescence method allowed identification of the pituitary cells targeted by APA, verifying the correspondence with the kind of hypopituitarism, also when present in subclinical stage. However, to carry out an international workshop comparing the detection of APA by immunofluorescence using different substrates could contribute to verify the best choice to improve the sensitivity and specificity of this method.

Hypothalamitis: a diagnostic and therapeutic challenge

To report an unusual case of biopsy-proven autoimmune hypophysitis with predominant hypothalamic involvement associated with empty sella, panhypopituitarism, visual disturbances and antipituitary antibodies positivity. We present the history, physical findings, hormonal assay results, imaging, surgical findings and pathology at presentation, together with a 2-year follow-up. A literature review on the hypothalamic involvement of autoimmune hypophysitis with empty sella was performed. A 48-year-old woman presented with polyuria, polydipsia, asthenia, diarrhea and vomiting. The magnetic resonance imaging (MRI) revealed a clear suprasellar (hypothalamic) mass, while the pituitary gland appeared atrophic. Hormonal testing showed panhypopituitarism and hyperprolactinemia; visual field examination was normal. Pituitary serum antibodies were positive. Two months later an MRI documented a mild increase of the lesion. The patient underwent biopsy of the lesion via a transsphenoidal approach. Histological diagnosis was lymphocytic "hypothalamitis". Despite 6 months of corticosteroid therapy, the patient developed bitemporal hemianopia and blurred vision, without radiological evidence of chiasm compression, suggesting autoimmune optic neuritis with uveitis. Immunosuppressive treatment with azathioprine was then instituted. Two months later, an MRI documented a striking reduction of the hypothalamic lesion and visual field examination showed a significant improvement. The lesion is stable at the 2-year follow-up. For the first time we demonstrated that "hypothalamitis" might be the possible evolution of an autoimmune hypophysitis, resulting in pituitary atrophy, secondary empty sella and panhypopituitarism. Although steroid treatment is advisable as a first line therapy, immunosuppressive therapy with azathioprine might be necessary to achieve disease control.

Prevalence of pituitary hormone dysfunction, metabolic syndrome, and impaired quality of life in retired professional football players: a prospective study

Hypopituitarism is common after moderate and severe traumatic brain injury (TBI). Herein, we address the association between mild TBI (mTBI) and pituitary and metabolic function in retired football players. Retirees 30-65 years of age, with one or more years of National Football League (NFL) play and poor quality of life (QoL) based on Short Form 36 (SF-36) Mental Component Score (MCS) were prospectively enrolled. Pituitary hormonal and metabolic syndrome (MetS) testing was performed. Using a glucagon stimulation test, growth hormone deficiency (GHD) was defined with a standard cut point of 3 ng/mL and with a more stringent body mass index (BMI)-adjusted cut point. Subjects with and without hormonal deficiency (HD) were compared in terms of QoL, International Index of Erectile Function (IIEF) scores, metabolic parameters, and football career data. Of 74 subjects, 6 were excluded because of significant non-football-related TBIs. Of the remaining 68 subjects (mean age, 47.3±10.2 years; median NFL years, 5; median NFL concussions, 3; mean BMI, 33.8±6.0), 28 (41.2%) were GHD using a peak GH cutoff of <3 ng/mL. However, with a BMI-adjusted definition of GHD, 13 of 68 (19.1%) were GHD. Using this BMI-adjusted definition, overall HD was found in 16 (23.5%) subjects: 10 (14.7%) with isolated GHD; 3 (4.4%) with isolated hypogonadism; and 3 (4.4%) with both GHD and hypogonadism. Subjects with HD had lower mean scores on the IIEF survey (p=0.016) and trended toward lower scores on the SF-36 MCS (p=0.113). MetS was present in 50% of subjects, including 5 of 6 (83%) with hypogonadism, and 29 of 62 (46.8%) without hypogonadism (p=0.087). Age, BMI, median years in NFL, games played, number of concussions, and acknowledged use of performance-enhancing steroids were similar between HD and non-HD groups. In summary, in this cohort of retired NFL players with poor QoL, 23.5% had HD, including 19% with GHD (using a BMI-adjusted definition), 9% with hypogonadism, and 50% had MetS. Although the cause of HD is unclear, these results suggest that GHD and hypogonadism may contribute to poor QoL, erectile dysfunction, and MetS in this population. Further study of pituitary function is warranted in athletes sustaining repetitive mTBI.

Human traumatic brain injury induces autoantibody response against glial fibrillary acidic protein and its breakdown products

The role of systemic autoimmunity in human traumatic brain injury (TBI) and other forms of brain injuries is recognized but not well understood. In this study, a systematic investigation was performed to identify serum autoantibody responses to brain-specific proteins after TBI in humans. TBI autoantibodies showed predominant immunoreactivity against a cluster of bands from 38-50 kDa on human brain immunoblots, which were identified as GFAP and GFAP breakdown products. GFAP autoantibody levels increased by 7 days after injury, and were of the IgG subtype predominantly. Results from in vitro tests and rat TBI experiments also indicated that calpain was responsible for removing the amino and carboxyl termini of GFAP to yield a 38 kDa fragment. Additionally, TBI autoantibody staining co-localized with GFAP in injured rat brain and in primary rat astrocytes. These results suggest that GFAP breakdown products persist within degenerating astrocytes in the brain. Anti-GFAP autoantibody also can enter living astroglia cells in culture and its presence appears to compromise glial cell health. TBI patients showed an average 3.77 fold increase in anti-GFAP autoantibody levels from early (0-1 days) to late (7-10 days) times post injury. Changes in autoantibody levels were negatively correlated with outcome as measured by GOS-E score at 6 months, suggesting that TBI patients with greater anti-GFAP immune-responses had worse outcomes. Due to the long lasting nature of IgG, a test to detect anti-GFAP autoantibodies is likely to prolong the temporal window for assessment of brain damage in human patients.

Neuropsychological and physiological correlates of fatigue following traumatic brain injury

BACKGROUND

Fatigue is a common and debilitating phenomenon experienced by individuals with traumatic brain injury (TBI) that can negatively influence rate and extent of functional recovery by reducing participation in brain injury rehabilitation services and increasing maladaptive lifestyle practices. The underlying mechanisms of TBI-related fatigue are not entirely understood and focused research on symptom reduction or prevention is limited.

REVIEW

The current review of the literature suggests that the aetiology of TBI-related fatigue can be viewed as a multifactorial and complex model impacting physiological systems (i.e. endocrine, skeletal muscle and cardiorespiratory) that can be directly or indirectly influenced by neuropsychological correlates including cognitive and psychological impairment. Distinguishing central from peripheral fatigue is helpful in this regard. Potential therapeutic strategies and pharmacological agents to help alleviate fatigue in this patient population are discussed.

Alternative causes of hypopituitarism: traumatic brain injury, cranial irradiation, and infections

Hypopituitarism often remains unrecognized due to subtle clinical manifestations. Anterior pituitary hormone deficiencies may present as isolated or multiple and may be transient or permanent. Traumatic brain injury (TBI) is recognized as a risk factor for hypopituitarism, most frequently presenting with isolated growth hormone deficiency (GHD). Data analysis shows that about 15% of patients with TBI have some degree of hypopituitarism which if not recognized may be mistakenly ascribed to persistent neurologic injury and cognitive impairment. Identification of predictors for hypopituitarism after TBI is important, one of them being the severity of TBI. The mechanisms involve lesions in the hypothalamic-pituitary axis and inflammatory changes in the central nervous system (CNS). With time, hypopituitarism after TBI may progress or reverse. Cranial irradiation is another important risk factor for hypopituitarism. Deficiencies in anterior pituitary hormone secretion (partial or complete) occur following radiation damage to the hypothalamic-pituitary region, the severity and frequency of which correlate with the total radiation dose delivered to the region and the length of follow-up. These radiation-induced hormone deficiencies are irreversible and progressive. Despite numerous case reports, the incidence of hypothalamic-pituitary dysfunction following infectious diseases of the CNS has been underestimated. Hypopituitarism usually relates to the severity of the disease, type of causative agent (bacterial, TBC, fungal, or viral) and primary localization of the infection. Unrecognized hypopituitarism may be misdiagnosed as postencephalitic syndrome, while the presence of a sellar mass with suprasellar extension may be misdiagnosed as pituitary macroadenoma in a patient with pituitary abscess which is potentially a life-threatening disease.

A five year prospective investigation of anterior pituitary function after traumatic brain injury: is hypopituitarism long-term after head trauma associated with autoimmunity?

Traumatic brain injury (TBI) has been recently recognized as a common cause of pituitary dysfunction. However, there are not sufficient numbers of prospective studies to understand the natural history of TBI induced hypopituitarism. The aim was to report the results of five years' prospective follow-up of anterior pituitary function in patients with mild, moderate and severe TBI. Moreover, we have prospectively investigated the associations between TBI induced hypopituitarism and presence of anti-hypothalamus antibodies (AHA) and anti-pituitary antibodies (APA). Twenty five patients (20 men, five women) were included who were prospectively evaluated 12 months and five years after TBI, and 17 of them also had a third-year evaluation. Growth hormone (GH) deficiency is the most common pituitary hormone deficit at one, three, and five years after TBI. Although most of the pituitary hormone deficiencies improve over time, there were substantial percentages of pituitary hormone deficiencies at the fifth year (28% GH, 4% adrenocorticotropic hormone [ACTH], and 4% gonadotropin deficiencies). Pituitary dysfunction was significantly higher in strongly AHA- and APA-positive (titers ≥1/16) patients at the fifth year. In patients with mild and moderate TBI, ACTH and GH deficiencies may improve over time in a considerable number of patients but, although rarely, may also worsen over the five-year period. However in severe TBI, ACTH and GH status of the patients at the first year evaluation persisted at the fifth year. Therefore, screening pituitary function after TBI for five years is important, especially in patients with mild TBI. Moreover, close strong associations between the presence of high titers of APA and/or AHA and hypopituitarism at the fifth year were shown for the first time.

Three years prospective investigation of pituitary functions following subarachnoid haemorrhage

Subarachnoid haemorrhage (SAH) is known to be related to pituitary dysfuntion in retrospective and short-term prospective studies. We aimed to investigate pituitary functions in patients with SAH in longer follow-up periods to demonstrate if pituitary hormone deficiencies recover, persist or new hormone deficiencies occur. Twenty patients with SAH, who were followed up for 3 years, were included in the present study. Patients were evaluated with basal hormone levels and glucagon stimulation test (GST).Serum basal cortisol and adrenocorticotropic hormone (ACTH) levels were found to be significantly elevated at 3rd year of SAH compared to 1st year. Other basal hormone levels at 3rd year did not show a significant change from the levels found at 1st year. One of the patients had ACTH deficiency at 1st year of SAH and recovered at 3rd year. Growth hormone (GH) deficiency, according to GST,was diagnosed in 4 patients. One patient with GH deficiency at first year was still deficient, 3 of them recovered and 3 patients were found to have new-onset GH deficiency 3 years after SAH. SAH is associated with anterior pituitary dysfunction and GH is the most frequently found deficient hormone in the patients. Although one year after SAH seems to be an appropriate time for the evaluation of pituitary functions, further follow-up may be required at least in some cases due to recovered and new-onset hormone deficiencies at 3rd year of SAH.

Pituitary autoimmunity in patients with diabetes mellitus and other endocrine disorders

OBJECTIVE

Pituitary autoimmunity is often found in association with other endocrine autoimmune or non-autoimmune diseases. Aim of the study was to assess the prevalence of serum pituitary antibodies (PitAb) in patients with Type 1 diabetes mellitus (T1DM) or Type 2 diabetes mellitus (T2DM).

RESEARCH DESIGN AND METHODS

In this casecontrol study 111 patients with T1DM, 110 patients with T2DM, and 214 healthy controls were enrolled in a tertiary referral center. Pituitary, thyroperoxidase, thyroglobulin, 21-hydroxylase, and parietal cell antibodies were assessed in all cases. Endocrine function was further assessed by basal hormone measurement and by dynamic tests, as well as a pituitary magnetic resonance imaging (MRI) was performed in those patients found positive for PitAb.

RESULTS

PitAb prevalence was higher in T1DM (4 out of 111, 3.6%) than in T2DM (0 out of 110, p=0.045) and in healthy subjects (1 out of 214, 0.5% p=0.029). Prevalence of other autoimmune diseases was significantly higher in patients with T1DM (45 out of 111, 40.5%) when compared with patients with T2DM (18 out of 110 T2DM, 16.3%, p<0.001). Patients with T1DM and PitAb positivity were found with a pituitary lesion at MRI in 2 cases and pituitary dysfunction in one case.

CONCLUSIONS

A significant association between pituitary autoimmunity and T1DM was found, in particular in subjects with one or more other endocrine autoimmune diseases.

Prospective investigation of pituitary functions in patients with acute infectious meningitis: is acute meningitis induced pituitary dysfunction associated with autoimmunity?

Previous case reports and retrospective studies suggest that pituitary dysfunction may occur after acute bacterial or viral meningitis. In this prospective study we assessed the pituitary functions, lipid profile and anthropometric measures in adults with acute bacterial or viral meningitis. Moreover, in order to investigate whether autoimmune mechanisms could play a role in the pathogenesis of acute meningitis-induced hypopituitarism we also investigated the anti-pituitary antibodies (APA) and anti-hypothalamus antibodies (AHA) prospectively. Sixteen patients (10 males, 6 females; mean ± SD age 40.9 ± 15.9) with acute infectious meningitis were included and the patients were evaluated in the acute phase, and at 6 and 12 months after the acute meningitis. In the acute phase 18.7% of the patients had GH deficiency, 12.5% had ACTH and FSH/LH deficiencies. At 12 months after acute meningitis 6 of 14 patients (42.8%) had GH deficiency, 1 of 14 patients (7.1%) had ACTH and FSH/LH deficiencies. Two of 14 patients (14.3%) had combined hormone deficiencies and four patients (28.6%) had isolated hormone deficiencies at 12 months. Four of 9 (44.4%) hormone deficiencies at 6 months were recovered at 12 months, and 3 of 8 (37.5%) hormone deficiencies at 12 months were new-onset hormone deficiencies. At 12 months there were significant negative correlations between IGF-I level vs. LDL-C, and IGF-I level vs. total cholesterol. The frequency of AHA and APA positivity was substantially high, ranging from 35 to 50% of the patients throughout the 12 months period. However there were no significant correlations between AHA or APA positivity and hypopituitarism. The risk of hypopituitarism, GH deficiency in particular, is substantially high in the acute phase, after 6 and 12 months of the acute infectious meningitis. Moreover we found that 6th month after meningitis is too early to make a decision for pituitary dysfunction and these patients should be screened for at least 12 months. In addition, the occurrence of AHA and APA positivity due to acute infectious meningitis was demonstrated for the first time. Further longer-term prospective investigations need to be carried out on a larger cohort of patients to understand the role of autoimmunity in the pathogenesis of late hypopituitarism after acute infectious meningitis.

Impact of head trauma on pituitary function

There have been in the past decade a growing number of studies relating head trauma to hypopituitarism. This condition may affect the rehabilitation process, and identification of such patients is therefore required. However, the widely different methods used so far for this purpose have provided inconsistent results. The incidence rate of hypopituitarism has probably been overestimated. This review focuses on the impact of head trauma on pituitary function, the diagnostic method, risk factors, and treatment options.

Endocrine changes after pediatric traumatic brain injury

Traumatic brain injury (TBI) is a very common occurrence in childhood, and can lead to devastating long term consequences. Recent research has focused on the potential endocrine consequences of TBI in adults. The research in children is less robust. This paper reviews current literature regarding TBI and possible hypothalamic and pituitary deficiencies in childhood. Acute endocrine changes are commonly found after TBI in pediatric patients, which can include changes in hypothalamic-pituitary-adrenal axis and antidiuretic hormone production and release. In the long term, both temporary and permanent alterations in pituitary function have been found. About 30% of children have hypopituitarism up to 5 years after injury. Growth hormone deficiency and disturbances in puberty are the most common, but children can also experience ACTH deficiency, diabetes insipidus, central hypothyroidism, and elevated prolactin. Every hormonal axis can be affected after TBI in children, although growth hormone deficiency and alterations in puberty are the most common. Because transient and permanent hypopituitarism is common after TBI, survivors should be screened serially for possible endocrine disturbances. These children should undergo routine surveillance at least 1 year after injury to ensure early detection of deficiencies in hormonal production in order to permit normal growth and development.

Sports-related chronic repetitive head trauma as a cause of pituitary dysfunction

Traumatic brain injury (TBI) is recognized as a cause of hypopituitarism even after mild TBI. Although over the past decade, a growing body of research has detailed neuroendocrine changes induced by TBI, the mechanisms and risk factors responsible for this pituitary dysfunction are still unclear. Around the world, sports-especially combative sports-are very popular. However, sports are not generally considered as a cause of TBI in most epidemiological studies, and the link between sports-related head trauma and hypopituitarism has not been investigated until recently. Thus, there is a paucity of data regarding this important concern. Because of the large number of young sports participants with near-normal life expectancy, the implications of undiagnosed or untreated postconcussion pituitary dysfunction can be dramatic. Understanding the pathophysiological mechanisms and risk factors of hypopituitarism caused by sports injuries is thus an important issue that concerns both medical staff and sponsors of sports. The aim of this paper was to summarize the best evidence for understanding the pathophysiological mechanisms and to discuss the current data and recommendations on sports-related head trauma as a cause of hypopituitarism.

Pituitary autoimmune disease: nuances in clinical presentation

Pituitary autoimmune disease is considered an autoimmune organ-specific disorder, characterized by a pituitary infiltration of lymphocytes, macrophages, and plasma cells that could lead to loss of pituitary function. Hypophysitis may be secondary to systemic diseases or infections. Primary pituitary hypophysitis is classified into lymphocytic, granulomatous, xanthomatous, mixed forms (lymphogranulomatous, xanthogranulomatous), necrotizing and IgG4 plasmacytic, according to the histological findings. Concerning lymphocytic hypophysitis (LH), it is characterized by lymphocytic infiltration and can be subclassified according to the affected area on: lymphocytic adenohypophysitis, lymphocytic infundibulo-neurohypophysitis and lymphocytic panhypophysitis. LH had always been considered a rare disease. Nevertheless, with improved imaging techniques, especially magnetic resonance imaging (MRI), LH diagnosis has been increased. This disease usually affects young women during pregnancy or postpartum period with headache, visual impairment, ACTH deficiency and a homogenous sellar mass with thickening of pituitary stalk in MRI. Definitive diagnosis depends on histopathological evaluation; nevertheless, a presumptive diagnosis could be done in a typical case. As no specific autoantigen was identified in LH, there is no antipituitary antibody (APA) method available for helping diagnosis. However, APA used in some centers for research could support an autoimmune origin for some hypopituitarism previously named as idiopathic, confirming nuances in clinical presentation of pituitary autoimmune disease. Therapeutic approach should be based on the grade of suspicious and clinical manifestations of LH.

Hypothalamo-Pituitary Dysfunction in Patients With Chronic Subdural Hematoma

Relatively frequent pituitary hormone deficiencies are observed after traumatic brain injury (TBI) and subarachnoid hemorrhage (SAH) and according to the published studies the neuroendocrine consequenses of traumatic brain injury are underdiagnosed. In a cohort of 59 patients (49 males, mean age 68.3 years, 36-88 years) after evacuation of subdural hematoma (SDH) were evaluated hypothalamo-pituitary functions one week after surgery, after three months and after one year. Hypogonadism was present in 26 % of patients in an acute phase, but in the majority had a transient character. Less than half of patients was GH deficient (GHD) according to the GHRH+arginine test. We did not find any serious case of hypocortisolism, hypothyroidism, diabetes insipidus centralis nor syndrome of inappropriate secretion of ADH (SIADH). Transient partial hypocortisolism was present in two cases, but resolved. We did not find relation between extension of SDH or clinical severity and development of hypopituitarism. In conclusion, in some patients with SDH growth hormone deficiency or hypogonadism was present. No serious hypocortisolism, hypothyroidism, diabetes insipidus nor SIADH was observed. The possibility of neuroendocrine dysfunction should be considered in patients with SDH, although the deficits are less frequent than in patients after TBI or SAH.

Pituitary autoimmunity is associated with hypopituitarism in patients with primary empty sella

OBJECTIVE

Some evidence suggests that late stage autoimmune hypophysitis (AH) may result in empty sella (ES). Aim of the study was to assess the prevalence of serum pituitary antibodies (PitAb) and their correlation with pituitary function in patients with ES.

DESIGN

In this casecontrol study 85 patients with primary ES, 16 patients with ES secondary to head trauma, 214 healthy controls, and 16 AH were enrolled in a tertiary referral center.

METHODS

PitAb were assessed in all cases and controls. Endocrine function was assessed by basal hormone measurement and dynamic testing in all ES cases.

RESULTS

PitAb prevalence was higher in primary ES (6%) than in healthy subjects (0.5% p=0.003) and lower than in AH patients (50%, p<0.0001). PitAb were not found in patients with secondary ES. Hypopituitarism was found in 49% of primary ES and in 62% of secondary ES (p=0.34). A positive correlation between the presence of PitAb and hypopituitarism was found in primary ES (p=0.02).

CONCLUSIONS

The significant association between pituitary autoimmunity and hypopituitarism suggests that ES, in selected cases, could be the final result of AH.

Manifesto for the current understanding and management of traumatic brain injury-induced hypopituitarism

Traumatic brain injury (TBI)-induced hypopituitarism remains a relevant medical problem, because it may affect a significant proportion of the population. In the last decade important studies have been published investigating pituitary dysfunction after TBI. Recently, a group of experts gathered and revisited the topic of TBI-induced hypopituitarism. During the 2-day meeting, the main issues of this topic were presented and discussed, and current understanding and management of TBI-induced hypopituitarism are summarized here.

Hypopituitarism following traumatic brain injury: determining factors for diagnosis

Neuroendocrine dysfunction, long recognized as a consequence of traumatic brain injury (TBI), is a major cause of disability that includes physical and psychological involvement with long-term cognitive, behavioral, and social changes. There is no standard procedure regarding at what time after trauma the diagnosis should be made. Also there is uncertainty on defining the best methods for diagnosis and testing and what types of patients should be selected for screening. Common criteria for evaluating these patients are required on account of the high prevalence of TBI worldwide and the potential new cases of hypopituitarism. The aim of this review is to clarify, based on the evidence, when endocrine assessment should be performed after TBI and which patients should be evaluated. Additional studies are still needed to know the impact of post-traumatic hypopituitarism and to assess the impact of hormone replacement in the prognosis.

Pituitary function in subjects with mild traumatic brain injury: a review of literature and proposal of a screening strategy

Traumatic brain injury (TBI) is an important public health problem all over the world. The level of consciousness of the patients and the severity of the brain injury is commonly evaluated by the Glascow Coma Scale as mild, moderate and severe TBI. When we consider the high frequency of mild TBI (MTBI) among the all TBI patients the burden of the pituitary dysfunction problem in this group could not be ignored. However, one of the most important and still unresolved questions is which patients with MTBI should be screened for hypopituitarism? Another type of head trauma which could be considered as the subgroup of MTBI is sports related chronic repetitive head trauma. Therefore, in this review we will discuss the frequency, characteristics and current management of pituitary dysfunction in patients with MTBI including the subjects exposed to sports related chronic mild head trauma.

Investigation of antihypothalamus and antipituitary antibodies in amateur boxers: is chronic repetitive head trauma-induced pituitary dysfunction associated with autoimmunity?

OBJECTIVE

Current data clearly demonstrate that sports-related chronic repetitive head trauma due to boxing might result in hypopituitarism. However, the mechanism of sports-related traumatic brain injury-induced pituitary dysfunction is still unclear. In order to understand whether autoimmune mechanisms could play a role in the pituitary dysfunction due to sports-related head trauma, we investigated the presence of antipituitary antibodies (APAs) and antihypothalamus antibodies (AHAs) in amateur boxers.

PATIENTS AND DESIGN

Sixty-one actively competing (n=44) or retired (n=17) male boxers (mean age, 26 years; range, 17-53) who had been evaluated regarding pituitary functions previously were included in the study. In all boxers and in 60 age/sex-similar normal controls, AHAs and APAs were investigated by an indirect immunofluorescence method.

RESULTS

AHAs were detected in 13 of 61 boxers (21.3%), and APAs were detected in 14 of 61 boxers (22.9%), but in none of the normal controls. Pituitary dysfunction was significantly higher in AHA-positive boxers (46.2%) than in AHA-negative boxers (10.4%) (P=0.003). There was a significant association between AHA positivity and hypopituitarism due to boxing (odds ratio: 7.37, 95% confidence interval 1.8-30.8). There was no significant association between APA positivity and hypopituitarism.

CONCLUSIONS

This study demonstrates for the first time the presence of AHAs and APAs in boxers who were exposed to sports-related head trauma. Moreover, the present investigation provides preliminary evidence that AHAs are associated with the development of pituitary dysfunction in boxers, thus suggesting that autoimmunity may have a role in the pathogenesis.

Different degrees of somatotroph ablation compromise pituitary growth hormone cell network structure and other pituitary endocrine cell types

We have generated transgenic mice with somatotroph-specific expression of a modified influenza virus ion channel, (H37A)M2, leading to ablation of GH cells with three levels of severity, dependent on transgene copy number. GH-M2(low) mice grow normally and have normal-size pituitaries but 40-50% reduction in pituitary GH content in adult animals. GH-M2(med) mice have male-specific transient growth retardation and a reduction in pituitary GH content by 75% at 42 d and 97% by 100 d. GH-M2(high) mice are severely dwarfed with undetectable pituitary GH. The GH secretory response of GH-M2(low) and GH-M2(med) mice to GH-releasing peptide-6 and GHRH was markedly attenuated. The content of other pituitary hormones was affected depending on transgene copy number: no effect in GH-M2(low) mice, prolactin and TSH reduced in GH-M2(med) mice, and all hormones reduced in GH-M2(high) mice. The effect on non-GH hormone content was associated with increased macrophage invasion of the pituitary. Somatotroph ablation affected GH cell network organization with limited disruption in GH-M2(low) mice but more severe disruption in GH-M2(med) mice. The remaining somatotrophs formed tight clusters after puberty, which contrasts with GHRH-M2 mice with a secondary reduction in somatotrophs that do not form clusters. A reduction in pituitary beta-catenin staining was correlated with GH-M2 transgene copy number, suggesting M2 expression has an effect on cell-cell communication in somatotrophs and other pituitary cell types. GH-M2 transgenic mice demonstrate that differing degrees of somatotroph ablation lead to correlated secondary effects on cell populations and cellular network organization.

Progesterone decreases cortical and sub-cortical edema in young and aged ovariectomized rats with brain injury

PURPOSE

Traumatic brain injury (TBI) -induced brain edema can be reduced by acute progesterone (PROG) treatment in young adult males and females, and in aged males. To extend these findings we tested these hypotheses: 1. Acute PROG treatment post-TBI will reduce cortical edema in aged females as much as in young adults. 2. TBI will induce edema in sub-cortical structures (SCS): the thalamus (TH), hypothalamus (HT), brain stem (BS) and anterior pituitary (AP). 3. Acute, systemic PROG treatment post-TBI will reduce edema in SCS.

METHODS

Young adult (n = 42) and aged (n = 40), bilaterally ovariectomized rats were given medial frontal cortical (MFC) contusion injury, treated with PROG (16 mg/kg body weight) or vehicle at 1, 6 and 24 hours post-injury and killed at 6, 24 and 48 hours post-injury. Their brains were removed and the target areas isolated and measured for water content.

RESULTS

TBI induced cortical and delayed sub-cortical edema. Acute PROG treatment decreased this edema. At 6 hours post-TBI serum PROG levels were substantially elevated in both young and aged, PROG-treated, groups, but were higher in the latter.

CONCLUSION

Acute PROG treatment post-TBI could prove an effective intervention to prevent or attenuate systemic, post-injury cortical and sub-cortical edema in young and aged females.