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.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Motor neurons and glia exhibit specific individualized responses to TDP-43 expression in a Drosophila model of amyotrophic lateral sclerosis

SUMMARY Amyotrophic lateral sclerosis (ALS) is a fatal disease characterized by complex neuronal and glial phenotypes. Recently, RNA-based mechanisms have been linked to ALS via RNA-binding proteins such as TDP-43, which has been studied in vivo using models ranging from yeast to rodents. We have developed a Drosophila model of ALS based on TDP-43 that recapitulates several aspects of pathology, including motor neuron loss, locomotor dysfunction and reduced survival. Here we report the phenotypic consequences of expressing wild-type and four different ALS-linked TDP-43 mutations in neurons and glia. We show that TDP-43-driven neurodegeneration phenotypes are dose- and age-dependent. In motor neurons, TDP-43 appears restricted to nuclei, which are significantly misshapen due to mutant but not wild-type protein expression. In glia and in the developing neuroepithelium, TDP-43 associates with cytoplasmic puncta. TDP-43-containing RNA granules are motile in cultured motor neurons, although wild-type and mutant variants exhibit different kinetic properties. At the neuromuscular junction, the expression of TDP-43 in motor neurons versus glia leads to seemingly opposite synaptic phenotypes that, surprisingly, translate into comparable locomotor defects. Finally, we explore sleep as a behavioral readout of TDP-43 expression and find evidence of sleep fragmentation consistent with hyperexcitability, a suggested mechanism in ALS. These findings support the notion that although motor neurons and glia are both involved in ALS pathology, at the cellular level they can exhibit different responses to TDP-43. In addition, our data suggest that individual TDP-43 alleles utilize distinct molecular mechanisms, which will be important for developing therapeutic strategies

Acute systemic DNA damage in youth does not impair immune defense with aging

Aging-related decline in immunity is believed to be the main driver behind decreased vaccine efficacy and reduced resistance to infections in older adults. Unrepaired DNA damage is known to precipitate cellular senescence, which was hypothesized to be the underlying cause of certain age-related phenotypes. Consistent with this, some hallmarks of immune aging were more prevalent in individuals exposed to whole-body irradiation (WBI), which leaves no anatomical repository of undamaged hematopoietic cells. To decisively test whether and to what extent WBI in youth will leave a mark on the immune system as it ages, we exposed young male C57BL/ 6 mice to sublethal WBI (0.5-4 Gy), mimicking human survivor exposure during nuclear catastrophe. We followed lymphocyte homeostasis thorough the lifespan, response to vaccination, and ability to resist lethal viral challenge in the old age. None of the irradiated groups showed significant differences compared with mock-irradiated (0 Gy) animals for the parameters measured. Even the mice that received the highest dose of sublethal WBI in youth (4 Gy) exhibited equilibrated lymphocyte homeostasis, robust T-and B-cell responses to live attenuated West Nile virus (WNV) vaccine and full survival following vaccination upon lethal WNV challenge. Therefore, a single dose of nonlethal WBI in youth, resulting in widespread DNA damage and repopulation stress in hematopoietic cells, leaves no significant trace of increased immune aging in a lethal vaccine challenge model.USPHS contract from the National Institute of Allergy and Infectious Diseases [HHSN272200900059C]This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Acute systemic DNA

Aging-related decline in immunity is believed to be the main driver behind decreased vaccine efficacy and reduced resistance to infections in older adults. Unrepaired DNA damage is known to precipitate cellular senescence, which was hypothesized to be the underlying cause of certain age-related phenotypes. Consistent with this, some hallmarks of immune aging were more prevalent in individuals exposed to whole-body irradiation (WBI), which leaves no anatomical repository of undamaged hematopoietic cells. To decisively test whether and to what extent WBI in youth will leave a mark on the immune system as it ages, we exposed young male C57BL/ 6 mice to sublethal WBI (0.5-4 Gy), mimicking human survivor exposure during nuclear catastrophe. We followed lymphocyte homeostasis thorough the lifespan, response to vaccination, and ability to resist lethal viral challenge in the old age. None of the irradiated groups showed significant differences compared with mock-irradiated (0 Gy) animals for the parameters measured. Even the mice that received the highest dose of sublethal WBI in youth (4 Gy) exhibited equilibrated lymphocyte homeostasis, robust T-and B-cell responses to live attenuated West Nile virus (WNV) vaccine and full survival following vaccination upon lethal WNV challenge. Therefore, a single dose of nonlethal WBI in youth, resulting in widespread DNA damage and repopulation stress in hematopoietic cells, leaves no significant trace of increased immune aging in a lethal vaccine challenge model.USPHS contract from the National Institute of Allergy and Infectious Diseases [HHSN272200900059C]This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]