Pituitary dysfunction following traumatic brain injury: clinical perspectives

Increased Adrenocorticotropic Hormone Levels Predict Recovery of Consciousness in Patients With Disorders of Consciousness

The potential influence of pituitary-related hormones (including both pituitary gland and target gland hormones) on functional recovery after traumatic brain injury has been observed. However, the relationship between these hormones and the recovery of consciousness in patients with disorders of consciousness (DOC) remains unclear. In this retrospective and observational study, 208 patients with DOC were recruited. According to the Glasgow Outcome Scale (GOS) scores after 6 months, patients with DOC were categorized into two subgroups: a favorable prognosis subgroup (n = 38) comprising those who regained consciousness (GOS score ≥3), and a poor prognosis subgroup (n = 156) comprising those who remained in DOC (GOS score <3). Comparative analyses of pituitary-related hormone levels between the two subgroups were conducted. Further, a binary logistic regression analysis was conducted to assess the predictive value of pituitary-related hormones for the patients' prognosis. The favorable prognosis subgroup showed a significant increase in adrenocorticotropic hormone (ACTH) levels (p = 0.036). Moreover, higher ACTH levels and shorter days since injury were significantly associated with a better prognosis, with odds ratios (ORs) of 0.928 (95% confidence interval [CI] = 0.873-0.985, p = 0.014) and 1.015 (95% CI = 1.005-1.026, p = 0.005), respectively. A subsequent receiver operating characteristic (ROC) analysis demonstrated the potential to predict patients' prognosis with an area under the curve value of 0.78, an overall accuracy of 75.5%, a sensitivity of 77.5%, and a specificity of 66.7%. Our findings indicate that ACTH levels could serve as a clinically valuable and convenient predictor for patients' prognosis.

Alterations in Serum miR-126-3p Levels over Time: A Marker of Pituitary Insufficiency following Head Trauma

INTRODUCTION

Traumatic brain injuries (TBIs) pose a high risk of pituitary insufficiency development in patients. We have previously reported alterations in miR-126-3p levels in sera from patients with TBI-induced pituitary deficiency.

METHODS

To investigate why TBI-induced pituitary deficiency develops only in some patients and to reveal the relationship between miR-126-3p with hormone axes, we used mice that were epigenetically modified with miR-126-3p at the embryonic stage. These modified mice were subjected to mild TBI (mTBI) according to the Marmarou's weight-drop model at 2 months of age. The levels of miR-126-3p were assessed at 1 and 30 days in serum after mTBI. Changes in miR-126-3p levels after mTBI of wild-type and miR-126-3p* modified mouse lines validated our human results. Additionally, hypothalamus, pituitary, and adrenal tissues were analyzed for transcripts and associated serum hormone levels.

RESULTS

We report that miR-126-3p directly affects hypothalamus-pituitary-adrenal (HPA) axis upregulation and ACTH secretion in the acute phase after mTBI. We also demonstrated that miR-126-3p suppresses Gnrh transcripts in the hypothalamus and pituitary, but this is not reflected in serum FSH/LH levels. The increase in ACTH levels in the acute phase may indicate that upregulation of miR-126-3p at the embryonic stage has a protective effect on the HPA axis after TBI. Notably, the most prominent transcriptional response is found in the adrenals, highlighting their role in the pathophysiology of TBI.

CONCLUSION

Our study revealed the role of miR-126-3p in TBI and pituitary deficiency developing after TBI, and the obtained data will significantly contribute to elucidating the mechanism of pituitary deficiency development after TBI and development of new diagnostic and treatment strategies.

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.

Optimal vitamin D level ameliorates neurological outcome and quality of life after traumatic brain injury: a clinical perspective

BACKGROUND

Deficiency of vitamin D along with traumatic brain injury (TBI) augments the risk of injury severity. This possibly affects the therapeutic regimen prescribed for TBI which may pessimistically affects its outcome.

METHODS

Studies literature search was conducted in Google Scholar and PubMed. The inclusions were studies performed clinically on both male and female. All included studies' references were also reviewed to find any additional relevance related to this review. Studies published in English were considered for this review. This review focuses upon the incidence of vitamin D deficiency in TBI and how it affects the Quality of life of the sufferer.

RESULTS

A total of 176 studies were reviewed and 58 were thoroughly focussed for review as they met inclusion criteria. These studies demonstrate that levels of vitamin D influence the recovery outcome after TBI. Vitamin D deficiency has been found to cause more deterioration in severe TBI than in patients with mild TBI.

CONCLUSION

Paucity of vitamin D significantly affects the outcome after brain injury. This clearly validates the necessity for screening of vitamin D levels in neurological deficit in order to reduce the risk of morbidity in terms of neurocognitive disorder.

Saliva Cortisol as a Biomarker of Injury in Youth Sport-Related Concussion

Increasing rates of sport-related concussion (SRC) in youth impose a significant burden on public health systems and the lives of young athletes. Accurate prediction for those likely to develop persistent post-concussion symptomology (PPCS) using a fluid biomarker, reflecting both acute injury and recovery processes, would provide the opportunity for early intervention. Cortisol, a stress hormone released through the hypothalamic-pituitary-adrenal (HPA) axis following injury, may provide a missing physiological link to clinical recovery. This cohort study investigated the change in saliva cortisol following SRC and the association between cortisol and symptom burden in pediatric ice hockey players. Further, the association between cortisol levels and medical clearance to return to play was explored. In total, cortisol samples from 233 players were included; 165 athletes (23.6% female) provided pre-injury saliva and 68 athletes (19.1% female) provided post-SRC saliva samples for cortisol analysis. Quantile (median) regressions were used to compare cortisol between pre-injury and post-SRC groups, and the association between total symptoms (/22) and symptom severity scores (/132) reported on the Sport Concussion Assessment Tool (SCAT)3/SCAT5 and post-SRC cortisol (adjusting for age, sex, history of concussion, and time from injury to sample collection). Results demonstrated significantly lower saliva cortisol in post-SRC athletes compared with the pre-injury group (β = -0.62, 95% confidence interval [CI; -1.08, -0.16], p = 0.009). Post-SRC cortisol was not significantly associated with the SCAT3/SCAT5 symptom totals or symptom severity scores; however, females were found to report more symptoms (β = 6.95, 95% CI [0.35, 13.55], p = 0.040) and greater symptom severity (β = 23.87, 95% CI [9.58, 38.15], p = 0.002) compared with males. Exploratory time-to-event analysis revealed a point estimate suggesting a potential association between low cortisol levels and days to medical clearance to return to play. Although preliminary, these findings suggest that the HPA axis may be dysregulated post-SRC. Further, our exploratory analysis and case presentation of post-injury outliers highlight the need to further research cortisol as a prognostic biomarker to inform individualized sex-specific care after SRC.

Chronic Anterior Pituitary Dysfunction Following Traumatic Head Injury: Prospective Study in Hospital Sultanah Aminah Johor Bahru, Malaysia

Background

Hypopituitarism following traumatic brain injury (TBI) is not rare however most patients were left undiagnosed and untreated. Association of post TBI hypopituitarism causing neurobehavioural and quality of life impairment. The aim of the study is to determine the incidence of the chronic anterior pituitary deficiency in patients with traumatic brain injury. Subsequently determine the risk factor and the outcome of the patient with chronic anterior pituitary dysfunction.

Methods

This is single centre cross-sectional study involved 105 traumatic head injury patients under the Neurosurgical Department Hospital Sultanah Aminah, Johor Bahru, Malaysia. The primary investigator will do an interview and the patients will be asked question to complete a questioner from SF-36 (36 questions). Subsequently, consent for participation will be taken and blood sampling will be done.

Results

Thirty-three patients were noted to have anterior pituitary dysfunction. The mean age was 36.97 ± 12.96 years old. Twenty-seven patients (32.5%) were male and six patients were female (27.3%). Chronic anterior pituitary dysfunction in patients with a severe traumatic head injury around 47.1% (23 patients), as compared to a moderate head injury (8 patients, 38.1%) and 2 sustained mild head injury (5.6%). The mean duration after the onset of trauma was 10.3 ± 1.79 months. All patient with anterior pituitary dysfunction had positive CT brain findings with 22 had subarachnoid haemorrhage (SAH) at the basal cistern and 27 patients had a base of skull fracture, where 52.1% of the patient underwent surgical intervention, 84.8% involved one axis and another 5 patients had two axes involved. Severity of the head injury (P < 0.001), prolonged duration of hospital stay (P = 0.014), radiological findings of a base of skull fracture (P < 0.001) and presence of SAH at basal cistern (P < 0.001) was significantly associated with pituitary dysfunction. The patient with anterior pituitary dysfunction has the lower 36-item Short Form Survey (SF-36) marks 56.3 ± 10.3.

Conclusion

The prevalence of hypopituitarism was 31%. Indicators are increased TBI severity, prolonged hospitalisation and positive finding in radiological assessment. Post-traumatic chronic anterior pituitary dysfunction also related with poor quality of life as showed by low SF-36 marks.

Correlation between vitamin D and cognitive function in patients with traumatic brain injury in China

OBJECTIVE

This study investigated changes in vitamin D levels in traumatic brain injury (TBI) patients and the relationship between vitamin D levels and cognitive function.

METHODS

Thirty-five TBI patients in our hospital were randomly selected, and baseline data were collected. 25-Hydroxyvitamin D (25(OH)D) plasma levels were determined within a month of hospitalization, and awareness and cognitive function were assessed using the Glasgow Coma Scale (GCS) and the Mini Mental State Examination (MMSE), respectively, on the day of blood collection. The data were statistically analyzed.

RESULTS

The MMSE and GCS scores were positively correlated (p < 0.05); higher MMSE scores were associated with higher GCS scores. Moreover, the total score was positively correlated with directional ability, memory, and attention, suggesting high internal consistency of the MMSE score, but no significant correlation with other indicators was observed. 25(OH)D was positively correlated with the injury site (p < 0.05), suggesting that frontal damage has a significant impact on the plasma level of 25(OH)D.

CONCLUSION

The plasma vitamin D level in TBI patients may indicate frontal lobe damage. The overall plasma level of 25(OH)D in TBI patients was not significantly correlated with cognitive function, but the incidence of cognitive impairment was higher with 25(OH)D level between 10 and 30 ng/ml.

Hypogonadism induced by surgical stress and brain trauma is reversed by human chorionic gonadotropin in male rats: A potential therapy for surgical and TBI-induced hypogonadism?

INTRODUCTION

Hypogonadotropic hypogonadism (HH) is an almost universal, yet underappreciated, endocrinological complication of traumatic brain injury (TBI). The goal of this study was to determine whether the developmental hormone human chorionic gonadotropin (hCG) treatment could reverse HH induced by a TBI.

METHODS

Plasma samples were collected at post-surgery/post-injury (PSD/PID) days -10, 1, 11, 19 and 29 from male Sprague-Dawley rats (5- to 6-month-old) that had undergone a Sham surgery (craniectomy alone) or CCI injury (craniectomy + bilateral moderate-to-severe CCI injury) and treatment with saline or hCG (400 IU/kg; i.m.) every other day.

RESULTS

Both Sham and CCI injury significantly decreased circulating testosterone (T), 11-deoxycorticosterone (11-DOC) and corticosterone concentrations to a similar extent (79.1% vs. 80.0%; 46.6% vs. 48.4%; 56.2% vs. 32.5%; respectively) by PSD/PID 1. hCG treatment  returned circulating T to baseline concentrations by PSD/PID 1 (8.9 ± 1.5 ng/ml and 8.3 ± 1.9 ng/ml; respectively) and was maintained through PSD/PID 29. hCG treatment significantly, but transiently, increased circulating progesterone (P4) ~3-fold (30.2 ± 10.5 ng/ml and 24.2 ± 5.8 ng/ml) above that of baseline concentrations on PSD 1 and PID 1, respectively. hCG treatment did not reverse hypoadrenalism following either procedure.

CONCLUSIONS

Together, these data indicate that (1) craniectomy is sufficient to induce persistent hypogonadism and hypoadrenalism, (2) hCG can reverse hypogonadism induced by a craniectomy or craniectomy +CCI injury, suggesting that (3) craniectomy and CCI injury induce a persistent hypogonadism by decreasing hypothalamic and/or pituitary function rather than testicular function in male rats. The potential role of hCG as a cheap, safe and readily available treatment for reversing surgery or TBI-induced hypogonadism is discussed.

Acute Neuroendocrine Profile in Predicting Outcomes in Severe Traumatic Brain Injury: A Study from a Tertiary Care Center in South India

BACKGROUND

Pituitary dysfunction following severe traumatic brain injury (sTBI) is significant and may be correlated with the outcomes.

AIMS AND OBJECTIVES

This study aimed to evaluate the early changes in pituitary hormone levels after sTBI and to correlate with outcomes in terms of severity and mortality.

METHODS

This was a prospective, observational study, involving consecutive patients of 16-60 years, with sTBI (Glasgow Coma Scale GCS < 9) presenting to the hospital within 24 h of trauma. Demographic and clinical data were collected. Serum samples were collected in the morning (08-10 am) on day 1 and day 4 for cortisol, thyroid-stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), and prolactin (Chemiluminescence immunoassay). Outcome was assessed in terms of mortality (which included both immediate and at 3 months) and Glasgow outcome scale at 3 months.

RESULTS

54 patients were studied. Mean cortisol on day 4 was 28.5 μg/dL in alive patients and 13.7 μg/dL in patients deceased at 3 months (P < 0.001). Patients who were deceased at 3 months had significantly lower T3 on day 4 (0.973 vs 1.4 ng/dL) and lower T4 (8.1 μg/L vs 6.1 μg/dL) as compared to patients who survived (P = 0.049 and 0.005, respectively). Acute phase TSH on day 4 levels were significantly lower in patients deceased at 3 months. There was no significant difference in the prolactin levels.

CONCLUSION

Day 4 cortisol, T3, T4, and TSH correlated with the outcomes at 3 months and hence have predictive value post-sTBI.

A Promising Subject-Level Classification Model for Acute Concussion Based on Cerebrovascular Reactivity Metrics

Concussion imaging research has primarily focused on neuronal disruption with lesser emphasis directed toward vascular dysfunction. However, blood flow metrics may be more sensitive than measures of neuronal integrity. Vascular dysfunction can be assessed by measuring cerebrovascular reactivity (CVR)-the change in cerebral blood flow per unit change in vasodilatory stimulus. CVR metrics, including speed and magnitude of flow responses to a standardized well-controlled vasoactive stimulus, are potentially useful for assessing individual subjects following concussion given that blood flow dysregulation is known to occur with traumatic brain injury. We assessed changes in CVR metrics to a standardized vasodilatory stimulus during the acute phase of concussion. Using a case control design, 20 concussed participants and 20 healthy controls (HCs) underwent CVR assessment measuring blood oxygen-level dependent (BOLD) magnetic resonance imaging using precise changes in end-tidal partial pressure of CO₂ (PETCO₂). Metrics were calculated for the whole brain, gray matter (GM), and white matter (WM) using sex-stratification. A leave-one-out receiver operating characteristic (ROC) analysis classified concussed from HCs based on CVR metrics. CVR magnitude was greater and speed of response faster in concussed participants relative to HCs, with WM showing higher classification accuracy compared with GM. ROC analysis for WM-CVR metrics revealed an area under the curve of 0.94 in males and 0.90 in females for speed and magnitude of response respectively. These greater than normal responses to a vasodilatory stimulus warrant further investigation to compare the predictive ability of CVR metrics against structural injury metrics for diagnosis and prognosis in acute concussion.

Evidence Limitations in Determining Sexually Dimorphic Outcomes in Pediatric Post-Traumatic Hypopituitarism and the Path Forward

Neuroendocrine dysfunction can occur as a consequence of traumatic brain injury (TBI), and disruptions to the hypothalamic-pituitary axis can be especially consequential to children. The purpose of our review is to summarize current literature relevant to studying sex differences in pediatric post-traumatic hypopituitarism (PTHP). Our understanding of incidence, time course, and impact is constrained by studies which are primarily small, are disadvantaged by significant methodological challenges, and have investigated limited temporal windows. Because hormonal changes underpin the basis of growth and development, the timing of injury and PTHP testing with respect to pubertal stage gains particular importance. Reciprocal relationships among neuroendocrine function, TBI, adverse childhood events, and physiological, psychological and cognitive sequelae are underconsidered influencers of sexually dimorphic outcomes. In light of the tremendous heterogeneity in this body of literature, we conclude with the common path upon which we must collectively arrive in order to make progress in understanding PTHP.

The protective effects of prolactin on brain injury

AIMS

Brain injuries based on their causes are divided into two categories, TBI and NTBI. TBI is caused by damages such as head injury, but non-physical injury causes NTBI. Prolactin is one of the blood factors that increase during brain injury. It has been assumed to play a regenerative role in post-injury recovery.

MATERIALS AND METHODS

In this review, various valid papers from electronic sources (including Web of Science, Scopus, PubMed, SID, Google Scholar, and ISI databases) used, which in them the protective effect of prolactin on brain injury investigated.

KEY FINDINGS

Inflammation following brain injury with the production of pro-inflammatory cytokines in the affected area can even lead to excitotoxicity and cell death in the damaged area. Medical brain damage treatments are long-term, and can have several side effects. Therefore, it is better to consider medication treatments that have fewer side effects and greater efficacy. Research suggests that prolactin has numerous regenerative effects on brain injury, and prevents cell death. Prolactin is one of the hormones produced in the body; therefore it has fewer side effects and may be more effective because it increases during brain injury.

SIGNIFICANCE

Prolactin can be used peripherally and centrally, and exerts its neuro regenerative effects against further damage post-TBI and NTBI.

Epidemiology of Pediatric Traumatic Brain Injury and Hypothalamic-Pituitary Disorders in Arizona

Traumatic brain injury (TBI) in children can result in long-lasting social, cognitive, and neurological impairments. In adults, TBI can lead to endocrinopathies (endocrine system disorders), but this is infrequently reported in children. Untreated endocrinopathies can elevate risks of subsequent health issues, such that early detection in pediatric TBI survivors can initiate clinical interventions. To understand the risk of endocrinopathies following pediatric TBI, we identified patients who had experienced a TBI and subsequently developed a new-onset hypothalamic regulated endocrinopathy (n = 498). We hypothesized that pediatric patients who were diagnosed with a TBI were at higher risk of being diagnosed with a central endocrinopathy than those without a prior diagnosis of TBI. In our epidemiological assessment, we identified pediatric patients enrolled in the Arizona Health Care Cost Containment System (AHCCCS) from 2008 to 2014 who were diagnosed with one of 330 TBI International Classification of Diseases (ICD)-9 codes and subsequently diagnosed with one of 14 central endocrinopathy ICD-9 codes. Additionally, the ICD-9 code data from over 600,000 Arizona pediatric patients afforded an estimate of the incidence, prevalence, relative risk, odds ratio, and number needed to harm, regarding the development of a central endocrinopathy after sustaining a TBI in Arizona Medicaid pediatric patients. Children with a TBI diagnosis had 3.22 times the risk of a subsequent central endocrine diagnosis compared with the general population (±0.28). Pediatric AHCCCS patients with a central endocrine diagnosis had 3.2-fold higher odds of a history of a TBI diagnosis than those without an endocrine diagnosis (±0.29). Furthermore, the number of patients with a TBI diagnosis for one patient to receive a diagnosis of a central endocrine diagnosis was 151.2 (±6.12). Female subjects were more likely to present with a central endocrine diagnosis after a TBI diagnosis compared to male subjects (64.1 vs. 35.9%). These results are the first state-wide epidemiological study conducted to determine the risk of developing a hypothalamic-pituitary disorder after a TBI in the pediatric population. Our results contribute to a body of knowledge demonstrating a TBI etiology for idiopathic endocrine disorders, and thus advise physicians with regard to TBI follow-up care that includes preventive screening for endocrine disorders.

Growth Hormone Deficiency Following Traumatic Brain Injury

Traumatic brain injury (TBI) is fairly common and annually affects millions of people worldwide. Post traumatic hypopituitarism (PTHP) has been increasingly recognized as an important and prevalent clinical entity. Growth hormone deficiency (GHD) is the most common pituitary hormone deficit in long-term survivors of TBI. The pathophysiology of GHD post TBI is thought to be multifactorial including primary and secondary mechanisms. An interplay of ischemia, cytotoxicity, and inflammation post TBI have been suggested, resulting in pituitary hormone deficits. Signs and symptoms of GHD can overlap with those of TBI and may delay rehabilitation/recovery if not recognized and treated. Screening for GHD is recommended in the chronic phase, at least six months to a year after TBI as GH may recover in those with GHD in the acute phase; conversely, it may manifest in those with a previously intact GH axis. Dynamic testing is the standard method to diagnose GHD in this population. GHD is associated with long-term poor medical outcomes. Treatment with recombinant human growth hormone (rhGH) seems to ameliorate some of these features. This review will discuss the frequency and pathophysiology of GHD post TBI, its clinical consequences, and the outcomes of treatment with GH replacement.

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.

The role of autoimmunity in pituitary dysfunction due to traumatic brain injury

PURPOSE

Traumatic brain injury (TBI) is one of the most common causes of mortality and long-term disability and it is associated with an increased prevalence of neuroendocrine dysfunctions. Post-traumatic hypopituitarism (PTHP) results in major physical, psychological and social consequences leading to impaired quality of life. PTHP can occur at any time after traumatic event, evolving through various ways and degrees of deficit, requiring appropriate screening for early detection and treatment. Although the PTHP pathophysiology remains to be elucitated, on the basis of proposed hypotheses it seems to be the result of combined pathological processes, with a possible role played by hypothalamic-pituitary autoimmunity (HPA). This review is aimed at focusing on this possible role in the development of PTHP and its potential clinical consequences, on the basis of the data so far appeared in the literature and of some results of personal studies on this issue.

METHODS

Scrutinizing the data so far appeared in literature on this topic, we have found only few studies evaluating the autoimmune pattern in affected patients, searching in particular for antipituitary and antihypothalamus autoantibodies (APA and AHA, respectively) by simple indirect immunofluorescence.

RESULTS

The presence of APA and/or AHA at high titers was associated with an increased risk of onset/persistence of PTHP.

CONCLUSIONS

HPA seems to contribute to TBI-induced pituitary damage and related PTHP. However, further prospective studies in a larger cohort of patients are needed to define etiopathogenic and diagnostic role of APA/AHA in development of post-traumatic hypothalamic/pituitary dysfunctions after a TBI.

Neuroendocrine Whiplash: Slamming the Breaks on Anabolic-Androgenic Steroids Following Repetitive Mild Traumatic Brain Injury in Rats May Worsen Outcomes

Sport-related concussion is an increasingly common injury among adolescents, with repetitive mild traumatic brain injuries (RmTBI) being a significant risk factor for long-term neurobiological and psychological consequences. It is not uncommon for younger professional athletes to consume anabolic-androgenic steroids (AAS) in an attempt to enhance their performance, subjecting their hormonally sensitive brains to potential impairment during neurodevelopment. Furthermore, RmTBI produces acute neuroendocrine dysfunction, specifically in the anterior pituitary, disrupting the hypothalamic-pituitary adrenal axis, lowering cortisol secretion that is needed to appropriately respond to injury. Some AAS users exhibit worse symptoms post-RmTBI if they quit their steroid regime. We sought to examine the pathophysiological outcomes associated with the abrupt cessation of the commonly abused AAS, Metandienone (Met) on RmTBI outcomes in rats. Prior to injury, adolescent male rats received either Met or placebo, and exercise. Rats were then administered RmTBIs or sham injuries, followed by steroid and exercise cessation (SEC) or continued treatment. A behavioral battery was conducted to measure outcomes consistent with clinical representations of post-concussion syndrome and chronic AAS exposure, followed by analysis of serum hormone levels, and qRT-PCR for mRNA expression and telomere length. RmTBI increased loss of consciousness and anxiety-like behavior, while also impairing balance and short-term working memory. SEC induced hyperactivity while Met treatment alone increased depressive-like behavior. There were cumulative effects whereby RmTBI and SEC exacerbated anxiety and short-term memory outcomes. mRNA expression in the prefrontal cortex, amygdala, hippocampus, and pituitary were modified in response to Met and SEC. Analysis of telomere length revealed the negative impact of SEC while Met and SEC produced changes in serum levels of testosterone and corticosterone. We identified robust changes in mRNA to serotonergic circuitry, neuroinflammation, and an enhanced stress response. Interestingly, Met treatment promoted glucocorticoid secretion after injury, suggesting that maintained AAS may be more beneficial than abstaining after mTBI.

Hypopituitarism post traumatic brain injury (TBI): review

Post-traumatic hypopituitarism (PTHP) is an important and relatively common complication of TBI (traumatic brain injury). A number of studies have shown that this clinical phenomenon can occur soon after TBI (acute) or later in the chronic phase. Patients with moderate to severe TBI are at a particular risk of developing PTHP. In the acute setting, it is important to monitor patients for hypoadrenalism as this confers a high risk for morbidity and even mortality. The gonadotrophin, growth hormone and TSH deficiencies are better defined in the chronic phase. Untreated PTHP can lead to delayed recovery, impaired rehabilitation and persistent neuropsychiatric symptoms. This review will discuss the frequency and natural history of PTHP and its clinical implications and propose a pathway for investigation and management of this still under-recognised entity.

The autoimmune basis of hypopituitarism in traumatic brain injury: fiction or reality?

Post-traumatic hypopituitarism has remained as an obscured cause of worsening morbidity and mortality in head injury patients. Researchers have for decades been puzzled by the mechanism of pituitary dysfunction in these cases. Amongst other causes like direct injury, vascular injury etc, an immunological basis of hypopituitarism has been suggested in some animal studies as well as human research. In this article, we have reviewed the latest articles and compiled the evidence which suggests for or against the role of autoimmunity in post-traumatic hypopituitarism or which defines the strength to which autoimmunity has been established as a cause of head-injury induced pituitary dysfunction.

Factors promoting vulnerability to dysregulated stress reactivity and stress-related disease

Effective coordination of the biological stress response is integral for the behavioural well-being of an organism. Stress reactivity is coordinated by an interplay of the neuroendocrine system and the sympathetic nervous system. The hypothalamic-pituitary-adrenal (HPA) axis plays a key role in orchestrating the bodily responses to stress, and the activity of the axis can be modified by a wide range of experiential events. This review focuses on several factors that influence subsequent HPA axis reactivity. Some of these factors include early-life adversity, exposure to chronic stress, immune activation and traumatic brain injury. The central premise is that each of these experiences serves as a general vulnerability factor that accelerates future HPA axis reactivity in ways that make individuals more sensitive to stress challenges, therefore feeding forward into the exacerbation of ongoing (or greater susceptibility toward) future stress-related disease states, especially as they pertain to negative affect and overall brain health.

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

BACKGROUND

Growth hormone deficiency (GHD) is a potential consequence of traumatic brain injury (TBI), including sport-related concussion (SRC). GH stimulation testing is required for definitive diagnosis; however, this is resource intensive and can be associated with adverse symptoms or risks. Measurement of serum IGF-1 is more practical and accessible, and pituitary tumour patients with hypopituitarism and low serum IGF-1 have been shown to have a high probability of GHD. We aimed to evaluate IGF-1 measurement for diagnosing GHD in our local TBI population.

METHODS

We conducted a retrospective chart review of patients evaluated for GHD at the TBI clinic and referred for GH stimulation testing with insulin tolerance test (ITT) or glucagon stimulation test (GST) since December 2013. We obtained demographics, TBI severity, IGF-1, data pertaining to pituitary function, and GH stimulation results. IGF-1 values were used to calculate z-scores per age and gender specific reference ranges. Receiver operator curve analysis was performed to evaluate diagnostic threshold of IGF-1 z-score for determining GHD by GST or ITT.

RESULTS

Sixty four patient charts were reviewed. 48 patients had mild, six had moderate, eight had severe TBI, and two had non-traumatic brain injuries. 47 patients underwent ITT or GST. 27 were confirmed to have GHD (peak hGH < 5 μg/L). IGF-1 level was within the age and gender specific reference range for all patients with confirmed GHD following GH stimulation testing. Only one patient had a baseline IGF-1 level below the age and gender specific reference range; this patient had a normal response to GH stimulation testing. ROC analysis showed IGF-1 z-score AUC f, confirming lack of diagnostic utility.

CONCLUSION

Baseline IGF-1 is not a useful predictor of GHD in our local TBI population, and therefore has no value as a screening tool. TBI patients undergoing pituitary evaluation will require a dynamic test of GH reserve.

Traumatic Brain Injury: At the Crossroads of Neuropathology and Common Metabolic Endocrinopathies

Building on the seminal work by Geoffrey Harris in the 1970s, the neuroendocrinology field, having undergone spectacular growth, has endeavored to understand the mechanisms of hormonal connectivity between the brain and the rest of the body. Given the fundamental role of the brain in the orchestration of endocrine processes through interactions among neurohormones, it is thus not surprising that the structural and/or functional alterations following traumatic brain injury (TBI) can lead to endocrine changes affecting the whole organism. Taking into account that systemic hormones also act on the brain, modifying its structure and biochemistry, and can acutely and chronically affect several neurophysiological endpoints, the question is to what extent preexisting endocrine dysfunction may set the stage for an adverse outcome after TBI. In this review, we provide an overview of some aspects of three common metabolic endocrinopathies, e.g., diabetes mellitus, obesity, and thyroid dysfunction, and how these could be triggered by TBI. In addition, we discuss how the complex endocrine networks are woven into the responses to sudden changes after TBI, as well as some of the potential mechanisms that, separately or synergistically, can influence outcomes after TBI.

Chronic Hypopituitarism Associated with Increased Postconcussive Symptoms Is Prevalent after Blast-Induced Mild Traumatic Brain Injury

The most frequent injury sustained by US service members deployed to Iraq or Afghanistan is mild traumatic brain injuries (mTBI), or concussion, by far most often caused by blast waves from improvised explosive devices or other explosive ordnance. TBI from all causes gives rise to chronic neuroendocrine disorders with an estimated prevalence of 25-50%. The current study expands upon our earlier finding that chronic pituitary gland dysfunction occurs with a similarly high frequency after blast-related concussions. We measured circulating hormone levels and accessed demographic and testing data from two groups of male veterans with hazardous duty experience in Iraq or Afghanistan. Veterans in the mTBI group had experienced one or more blast-related concussion. Members of the deployment control (DC) group encountered similar deployment conditions but had no history of blast-related mTBI. 12 of 39 (31%) of the mTBI participants and 3 of 20 (15%) veterans in the DC group screened positive for one or more neuroendocrine disorders. Positive screens for growth hormone deficiency occurred most often. Analysis of responses on self-report questionnaires revealed main effects of both mTBI and hypopituitarism on postconcussive and posttraumatic stress disorder (PTSD) symptoms. Symptoms associated with pituitary dysfunction overlap considerably with those of PTSD. They include cognitive deficiencies, mood and anxiety disorders, sleep problems, diminished quality of life, deleterious changes in metabolism and body composition, and increased cardiovascular mortality. When such symptoms are due to hypopituitarism, they may be alleviated by hormone replacement. These findings suggest consideration of routine post-deployment neuroendocrine screening of service members and veterans who have experienced blast-related mTBI and are reporting postconcussive symptoms.

Sport Concussion and the Female Athlete

Sport concussion (SC) has emerged as a major health concern in the medical community and general public owing to increased research and media attention, which has primarily focused on male athletes. Female athletes have an equal, if not increased, susceptibility to SC. An ever-growing body of research continues to compare male and female athletes in terms of SC before and after an injury. Clinicians must be cognizant of this literature to make evidence-based clinical decision when providing care to female athletes and discern between dated and/or unsupported claims in terms of SC.

Post-Traumatic Hypopituitarism-Who Should Be Screened, When, and How?

Traumatic brain injury (TBI) remains a major, global public health concern. Over the last 15 years, a significant body of evidence has emerged demonstrating that post-traumatic hypopituitarism (PTHP) is a common and clinically significant consequence of TBI. Non-specific symptomology and the lack of an agreed approach to screening for PTHP has led to significant under-diagnosis of this debilitating disease. In this review, we will discuss the frequency and clinical significance of acute and chronic PTHP as described in the current literature highlighting the evidence base for screening and hormone replacement in these patients. We will also offer a pragmatic approach to identifying relevant anterior pituitary dysfunction after TBI and a follow-up strategy for those patients. Specific controversies and remaining unanswered questions will be addressed.

Experimental repetitive mild traumatic brain injury induces deficits in trabecular bone microarchitecture and strength in mice

To evaluate the long-term consequence of repetitive mild traumatic brain injury (mTBI) on bone, mTBI was induced in 10-week-old female C57BL/6J mice using a weight drop model, once per day for 4 consecutive days at different drop heights (0.5, 1 and 1.5 m) and the skeletal phenotype was evaluated at different time points after the impact. In vivo micro-CT (μ-CT) analysis of the tibial metaphysis at 2, 8 and 12 weeks after the impact revealed a 5%-32% reduction in trabecular bone mass. Histomorphometric analyses showed a reduced bone formation rate in the secondary spongiosa of 1.5 m impacted mice at 12 weeks post impact. Apparent modulus (bone strength), was reduced by 30% (P<0.05) at the proximal tibial metaphysis in the 1.5 m drop height group at 2 and 8 weeks post impact. Ex vivo μ-CT analysis of the fifth lumbar vertebra revealed a significant reduction in trabecular bone mass at 12 weeks of age in all three drop height groups. Serum levels of osteocalcin were decreased by 22%, 15%, and 19% in the 0.5, 1.0 and 1.5 m drop height groups, respectively, at 2 weeks post impact. Serum IGF-I levels were reduced by 18%-32% in mTBI mice compared to contro1 mice at 2 weeks post impact. Serum osteocalcin and IGF-I levels correlated with trabecular BV/TV (r² =0.14 and 0.16, P<0.05). In conclusion, repetitive mTBI exerts significant negative effects on the trabecular bone microarchitecture and bone mechanical properties by influencing osteoblast function via reduced endocrine IGF-I actions.

Neuroendocrine Dysfunction in a Young Athlete With Concussion: A Case Report

An 18-year-old female ringette and basketball player presented to our sport concussion clinic 27 months after concussion with fatigue, headache, exercise intolerance, polyuria, nocturia, and difficulties concentrating. Her history was remarkable for 4 previous concussions. Her neurologic examination was normal. Neuroendocrine screen including thyroid function, morning cortisol, glucose, and insulin-like growth factor-1 (screening test for growth hormone deficiency) were normal. Further testing for growth hormone deficiency with an insulin hypoglycemia test revealed severe growth hormone deficiency. Urine and serum electrolytes were borderline normal, suggesting partial diabetes insipidus. Treatments with growth hormone replacement lead to complete recovery. This case highlights the importance of maintaining a high index of suspicion for neuroendocrine abnormalities in athletes with persistent symptoms after sport concussion. Symptoms can be nonspecific and go undiagnosed for years, but appropriate recognition and treatment can restore function.

Classical and non-classical causes of GH deficiency in adults

Growth hormone deficiency (GHD) can develop due to a variety of conditions, and may occur either as isolated or multiple pituitary hormone deficiencies. It has been previously demonstrated that GH is one of the most frequent hormonal deficiencies in adult patients with hypopituitarism. The most frequent classical causes of adult-onset GHD (AO-GHD) are pituitary adenomas and/or their treatment. However, during the last decade an increasing number of studies from different parts of the world have revealed that non-tumoural causes of hypopituitarism are more common than previously known. Therefore, in this review our aim is to briefly summarize the classical and non-classical acquired causes of GHD in adults.

Conjugated Linoleic Acid Administration Induces Amnesia in Male Sprague Dawley Rats and Exacerbates Recovery from Functional Deficits Induced by a Controlled Cortical Impact Injury

Long-chain polyunsaturated fatty acids like conjugated linoleic acids (CLA) are required for normal neural development and cognitive function and have been ascribed various beneficial functions. Recently, oral CLA also has been shown to increase testosterone (T) biosynthesis, which is known to diminish traumatic brain injury (TBI)-induced neuropathology and reduce deficits induced by stroke in adult rats. To test the impact of CLA on cognitive recovery following a TBI, 5-6 month old male Sprague Dawley rats received a focal injury (craniectomy + controlled cortical impact (CCI; n = 17)) or Sham injury (craniectomy alone; n = 12) and were injected with 25 mg/kg body weight of Clarinol® G-80 (80% CLA in safflower oil; n = 16) or saline (n = 13) every 48 h for 4 weeks. Sham surgery decreased baseline plasma progesterone (P4) by 64.2% (from 9.5 ± 3.4 ng/mL to 3.4 ± 0.5 ng/mL; p = 0.068), T by 74.6% (from 5.9 ± 1.2 ng/mL to 1.5 ± 0.3 ng/mL; p < 0.05), 11-deoxycorticosterone (11-DOC) by 37.5% (from 289.3 ± 42.0 ng/mL to 180.7 ± 3.3 ng/mL), and corticosterone by 50.8% (from 195.1 ± 22.4 ng/mL to 95.9 ± 2.2 ng/mL), by post-surgery day 1. CCI injury induced similar declines in P4, T, 11-DOC and corticosterone (58.9%, 74.6%, 39.4% and 24.6%, respectively) by post-surgery day 1. These results suggest that both Sham surgery and CCI injury induce hypogonadism and hypoadrenalism in adult male rats. CLA treatment did not reverse hypogonadism in Sham (P4: 2.5 ± 1.0 ng/mL; T: 0.9 ± 0.2 ng/mL) or CCI-injured (P4: 2.2 ± 0.9 ng/mL; T: 1.0 ± 0.2 ng/mL, p > 0.05) animals by post-injury day 29, but rapidly reversed by post-injury day 1 the hypoadrenalism in Sham (11-DOC: 372.6 ± 36.6 ng/mL; corticosterone: 202.6 ± 15.6 ng/mL) and CCI-injured (11-DOC: 384.2 ± 101.3 ng/mL; corticosterone: 234.6 ± 43.8 ng/mL) animals. In Sham surgery animals, CLA did not alter body weight, but did markedly increase latency to find the hidden Morris Water Maze platform (40.3 ± 13.0 s) compared to saline treated Sham animals (8.8 ± 1.7 s). In CCI injured animals, CLA did not alter CCI-induced body weight loss, CCI-induced cystic infarct size, or deficits in rotarod performance. However, like Sham animals, CLA injections exacerbated the latency of CCI-injured rats to find the hidden MWM platform (66.8 ± 10.6 s) compared to CCI-injured rats treated with saline (30.7 ± 5.5 s, p < 0.05). These results indicate that chronic treatment of CLA at a dose of 25 mg/kg body weight in adult male rats over 1-month 1) does not reverse craniectomy- and craniectomy + CCI-induced hypogonadism, but does reverse craniectomy- and craniectomy + CCI-induced hypoadrenalism, 2) is detrimental to medium- and long-term spatial learning and memory in craniectomized uninjured rats, 3) limits cognitive recovery following a moderate-severe CCI injury, and 4) does not alter body weight.

Traumatic brain injuries

Traumatic brain injuries (TBIs) are clinically grouped by severity: mild, moderate and severe. Mild TBI (the least severe form) is synonymous with concussion and is typically caused by blunt non-penetrating head trauma. The trauma causes stretching and tearing of axons, which leads to diffuse axonal injury - the best-studied pathogenetic mechanism of this disorder. However, mild TBI is defined on clinical grounds and no well-validated imaging or fluid biomarkers to determine the presence of neuronal damage in patients with mild TBI is available. Most patients with mild TBI will recover quickly, but others report persistent symptoms, called post-concussive syndrome, the underlying pathophysiology of which is largely unknown. Repeated concussive and subconcussive head injuries have been linked to the neurodegenerative condition chronic traumatic encephalopathy (CTE), which has been reported post-mortem in contact sports athletes and soldiers exposed to blasts. Insights from severe injuries and CTE plausibly shed light on the underlying cellular and molecular processes involved in mild TBI. MRI techniques and blood tests for axonal proteins to identify and grade axonal injury, in addition to PET for tau pathology, show promise as tools to explore CTE pathophysiology in longitudinal clinical studies, and might be developed into diagnostic tools for CTE. Given that CTE is attributed to repeated head trauma, prevention might be possible through rule changes by sports organizations and legislators.

Prevalence and correlates of vitamin D deficiency in adults after traumatic brain injury

OBJECTIVES

Traumatic brain injury (TBI) is a major cause of long-term disability with variable recovery. Preclinical studies suggest that vitamin D status influences the recovery after TBI. However, there is no published clinical data on links between vitamin D status and TBI outcomes. The aim was to determine the (i) prevalence of vitamin D deficiency/insufficiency, and associations of vitamin D status with (ii) demographic factors and TBI severity, and with (iii) cognitive function, symptoms and quality of life, in adults after TBI.

DESIGN

Retrospective audit of patients seen between July 2009 and March 2015. Serum vitamin D (25-hydroxy-cholecalciferol) was categorized as deficient (<40 nmol/l), insufficient (40-70 nmol/l) or replete (>70 nmol/l).

PATIENTS

A total of 353 adults seen in tertiary hospital clinic (75·4% lighter skinned, 74·8% male, age median 35·1 year, range 26·6-48·3 year), 0·3-56·5 months after TBI (74·5% moderate-severe).

MEASUREMENTS

Serum vitamin D concentrations; Addenbrooke's Cognitive Examination (ACE-R), Beck Depression Inventory-II (BDI-II), SF-36 Quality of Life, Pittsburgh Sleep Quality Index.

RESULTS

In total, 46·5% of patients after TBI had vitamin D deficiency and 80·2% insufficiency/deficiency. Patients with vitamin D deficiency had lower ACE-R scores than those of vitamin D replete (mean effect size ± SEM 4·5 ± 2·1, P = 0·034), and higher BDI-II scores than those of vitamin D insufficient (4·5 ± 1·6, P = 0·003), correcting for age, gender, time since TBI and TBI severity. There was no association between vitamin D status and markers of TBI severity, sleep or quality of life.

CONCLUSION

Vitamin D deficiency is common in patients after TBI and associated with impaired cognitive function and more severe depressive symptoms.

Diffuse traumatic brain injury affects chronic corticosterone function in the rat

As many as 20-55% of patients with a history of traumatic brain injury (TBI) experience chronic endocrine dysfunction, leading to impaired quality of life, impaired rehabilitation efforts and lowered life expectancy. Endocrine dysfunction after TBI is thought to result from acceleration-deceleration forces to the brain within the skull, creating enduring hypothalamic and pituitary neuropathology, and subsequent hypothalamic-pituitary endocrine (HPE) dysfunction. These experiments were designed to test the hypothesis that a single diffuse TBI results in chronic dysfunction of corticosterone (CORT), a glucocorticoid released in response to stress and testosterone. We used a rodent model of diffuse TBI induced by midline fluid percussion injury (mFPI). At 2months postinjury compared with uninjured control animals, circulating levels of CORT were evaluated at rest, under restraint stress and in response to dexamethasone, a synthetic glucocorticoid commonly used to test HPE axis regulation. Testosterone was evaluated at rest. Further, we assessed changes in injury-induced neuron morphology (Golgi stain), neuropathology (silver stain) and activated astrocytes (GFAP) in the paraventricular nucleus (PVN) of the hypothalamus. Resting plasma CORT levels were decreased at 2months postinjury and there was a blunted CORT increase in response to restraint induced stress. No changes in testosterone were measured. These changes in CORT were observed concomitantly with altered complexity of neuron processes in the PVN over time, devoid of neuropathology or astrocytosis. Results provide evidence that a single moderate diffuse TBI leads to changes in CORT function, which can contribute to the persistence of symptoms related to endocrine dysfunction. Future experiments aim to evaluate additional HP-related hormones and endocrine circuit pathology following diffuse TBI.

The head that wears the crown: Henry VIII and traumatic brain injury

Henry VIII of England is one of the most controversial figures in European history. He was born on 28 June 1491 as the second son of Henry VII and Elizabeth of York and became the heir to the English throne after his elder brother died prematurely. A contradictory picture of Henry's character emerges from history: the young Henry was a vigorous, generous and intelligent king who saw early military and naval successes. In contrast, in his later years he became cruel, petty and tyrannical. His political paranoia and military misjudgements are in direct contrast to his earlier successes and promise. Several hypotheses have been put forward regarding his transformation from a renaissance king to a later medieval tyrant, including endocrinopathies, psychiatric illnesses and traumatic brain injury. In this paper we examine the historical evidence linking the change in Henry's personality and health problems to traumatic brain injury. To our knowledge this is the first systematic neurological study of traumatic brain injury in Henry VIII.