Ionizing Radiation Dose Differentially Affects the Host-Microbe Relationship over Time.

Microorganisms that colonize in or on a host play significant roles in regulating the host's immunological fitness and bioenergy production, thus controlling the host's stress responses. Radiation elicits a pro-inflammatory and bioenergy-expensive state, which could influence the gut microbial compositions and, therefore, the host-microbe bidirectional relationship. To test this hypothesis, young adult mice were exposed to total body irradiation (TBI) at doses of 9.5 Gy and 11 Gy, respectively. The irradiated mice were euthanized on days 1, 3, and 9 post TBI, and their descending colon contents (DCCs) were collected. The 16S ribosomal RNAs from the DCCs were screened to find the differentially enriched bacterial taxa due to TBI. Subsequently, these data were analyzed to identify the metagenome-specific biofunctions. The bacterial community of the DCCs showed increased levels of diversity as time progressed following TBI. The abundance profile was the most divergent at day 9 post 11 Gy TBI. For instance, an anti-inflammatory and energy-harvesting bacterium, namely, Firmicutes, became highly abundant and co-expressed in the DCC with pro-inflammatory Deferribacteres at day 9 post 11 Gy TBI. A systems evaluation found a diverging trend in the regulation profiles of the functional networks that were linked to the bacteria and metabolites of the DCCs, respectively. Additionally, the network clusters associated with lipid metabolism and bioenergy synthesis were found to be activated in the DCC bacteria but inhibited in the metabolite space at day 9 post 11 Gy. Taking these results together, the present analysis indicated a disrupted mouse-bacteria symbiotic relationship as time progressed after lethal irradiation. This information can help develop precise interventions to ameliorate the symptoms triggered by TBI.

Impact of dietary changes on retinal neuronal plasticity in rodent models of physical and psychological trauma.

Introduction: Blast injury has been implicated as the major cause of traumatic brain injury (TBI) and ocular system injury, in military operations in Iraq and Afghanistan. Soldiers exposed to traumatic stress also have undiagnosed, chronic vision problems. Here we hypothesize that excessive intake of ω-6 fatty acid linoleic acid (LA) and insufficiency of dietary long chain ω-3 polyunsaturated fatty acids (PUFAs, e.g., docosahexaenoic acid; DHA) would dysregulate endocannabinoid-mediated neuronal plasticity and immune response. The study objective was to determine the effect of blast-TBI and traumatic stress on retinal gene expression and assess the role of dietary deficiency of long chain ω-3 PUFAs on the vulnerability to these injury models. Methods: Linoleic acid was used as an independent variable to reflect the dietary increase in LA from 1 percent of energy (en%) to 8 en% present in the current western diets, and these custom LA diets were also devoid of long chain ω-3 PUFAs. Animals were exposed to a simulated blast overpressure wave followed by a weight drop head-concussion to induce TBI. A Separate group of rats were subjected to traumatic stress by a forced immersion underwater. Results: Our findings showed that blast-TBI exposure, post 14 days, produced significant neuropathological changes such as axonal degeneration in the brain optic tracts from all the three diet groups, especially in rats fed the DHA-deprived 1 en% LA diet. Transcriptomic analysis showed that presence of DHA in the house chow diet prevented blast-induced disruption of neuronal plasticity by activating molecular networks like SNARE signaling, endocannabinoid pathway, and synaptic long-term depression when compared to DHA-deprived 8 en% LA diet group. Under traumatic stress, retinal synaptic function, neurovascular coupling, and opioid signaling mechanisms were dysregulated in rodents fed DHA-deficient diets (i.e., 8 en% LA and 1 en% LA), where reducing the levels of ω-6 linoleic acid from 8 en% to 1 en% was associated with increased neuronal plasticity and suppressed immune signaling. Conclusion: The findings of our study suggest that deprivation of long chain ω-3 PUFAs in the diet affects endocannabinoid-mediated neuronal plasticity, vascular function and inflammatory response that could influence the resistance of veterans to TBI and psychological trauma.

Fentanyl Overdose Causes Prolonged Cardiopulmonary Dysregulation in Male SKH1 Mice.

Fentanyl overdose is a survivable condition that commonly resolves without chronic overt changes in phenotype. While the acute physiological effects of fentanyl overdose, such as opioid-induced respiratory depression (OIRD) and Wooden Chest Syndrome, represent immediate risks of lethality, little is known about longer-term systemic or organ-level impacts for survivors. In this study, we investigated the effects of a single, bolus fentanyl overdose on components of the cardiopulmonary system up to one week post. SKH1 mice were administered subcutaneous fentanyl at the highest non-lethal dose (62 mg/kg), LD10 (110 mg/kg), or LD50 (135 mg/kg), before euthanasia at 40 min, 6 h, 24 h, or 7 d post-exposure. The cerebral cortex, heart, lungs, and plasma were assayed using an immune monitoring 48-plex panel. The results showed significantly dysregulated cytokine, chemokine, and growth factor concentrations compared to time-matched controls, principally in hearts, then lungs and plasma to a lesser extent, for the length of the study, with the cortex largely unaffected. Major significant analytes contributing to variance included eotaxin-1, IL-33, and betacellulin, which were generally downregulated across time. The results of this study suggest that cardiopulmonary toxicity may persist from a single fentanyl overdose and have wide implications for the endurance of the expanding population of survivors.

Metabolites: a converging node of host and microbe to explain meta-organism.

Meta-organisms encompassing the host and resident microbiota play a significant role in combatting diseases and responding to stress. Hence, there is growing traction to build a knowledge base about this ecosystem, particularly to characterize the bidirectional relationship between the host and microbiota. In this context, metabolomics has emerged as the major converging node of this entire ecosystem. Systematic comprehension of this resourceful omics component can elucidate the organism-specific response trajectory and the communication grid across the ecosystem embodying meta-organisms. Translating this knowledge into designing nutraceuticals and next-generation therapy are ongoing. Its major hindrance is a significant knowledge gap about the underlying mechanisms maintaining a delicate balance within this ecosystem. To bridge this knowledge gap, a holistic picture of the available information has been presented with a primary focus on the microbiota-metabolite relationship dynamics. The central theme of this article is the gut-brain axis and the participating microbial metabolites that impact cerebral functions.

Biomarker discovery process at binomial decision point (2BDP): Analytical pipeline to construct biomarker panel.

A clinical incident is typically manifested by several molecular events; therefore, it seems logical that a successful diagnosis, prognosis, or stratification of a clinical landmark require multiple biomarkers. In this report, we presented a machine learning pipeline, namely "Biomarker discovery process at binomial decision point" (2BDP) that took an integrative approach in systematically curating independent variables (e.g., multiple molecular markers) to explain an output variable (e.g., clinical landmark) of binary in nature. In a logical sequence, 2BDP includes feature selection, unsupervised model development and cross validation. In the present work, the efficiency of 2BDP was demonstrated by finding three biomarker panels that independently explained three stages of Alzheimer's disease (AD) marked as Braak stages I, II and III, respectively. We designed three assortments from the entire cohort based on these Braak stages; subsequently, each assortment was split into two populations at Braak score I, II or III. 2BDP systematically integrated random forest and logistic regression fitting model to find biomarker panels with minimum features that explained these three assortments, e.g., significantly differentiated two populations segregated by Braak stage I, II or III, respectively. Thereafter, the efficacies of these panels were measured by the area under the curve (AUC) values of the receiver operating characteristic (ROC) plot. The AUC-ROC was calculated by two cross-validation methods. Final set of gene markers was a mix of novel and a priori established AD signatures. These markers were weighted by unique coefficients and linearly connected in a group of 2-10 to explain Braak stage I, II or III by AUC ≥ 0.8. Small sample size and a lack of distinctly recruited Training and Test sets were the limitations of the present undertaking; yet 2BDP demonstrated its capability to curate a panel of optimum numbers of biomarkers to describe the outcome variable with high efficacy.

Early to sustained impacts of lethal radiation on circulating miRNAs in a minipig model.

Early diagnosis of lethal radiation is imperative since its intervention time windows are considerably short. Hence, ideal diagnostic candidates of radiation should be easily accessible, enable to inform about the stress history and objectively triage subjects in a time-efficient manner. Therefore, the small molecules such as metabolites and microRNAs (miRNAs) from plasma are legitimate biomarker candidate for lethal radiation. Our objectives were to comprehend the radiation-driven molecular pathogenesis and thereby determine biomarkers of translational potential. We investigated an established minipig model of LD70/45 total body irradiation (TBI). In this pilot study, plasma was collected pre-TBI and at multiple time points post-TBI. The majority of differentially expressed miRNAs and metabolites were perturbed immediately after TBI that potentially underlined the severity of its acute impact. The integrative network analysis of miRNA and metabolites showed a cohesive response; the early and consistent perturbations of networks were linked to cancer and the shift in musculoskeletal atrophy synchronized with the comorbidity-networks associated with inflammation and bioenergy synthesis. Subsequent comparative pipeline delivered 92 miRNAs, which demonstrated sequential homology between human and minipig, and potentially similar responses to lethal radiation across these two species. This panel promised to retrospectively inform the time since the radiation occurred; thereby could facilitate knowledge-driven interventions.

Pathological Spectrum and ß-APP Immunoreactivity as a Diagnostic Tool of Diffuse Axonal Injury following Traumatic Brain Injury: A Novel Classification.

Aim Different deposition patterns and grading systems used to define and identify DAI remain discordant and to date these are a challenge in clinical practice. Our main objective was to study the post-mortem axonal changes and develop a grading system to identify DAI on the basis of histopathological and immunoreactive ß-amyloid precursor protein (ß-APP) observations in severe TBI cases. Methods Prospective study with 35 decedents with sTBI (GCS score ≤ 8) was conducted and samples were collected from three different sites-corpus callosum, thalamus and brain stem. Serial sections from each site were stained with hematoxylin and eosin (H&E), and immunohistochemistry (IHC) of ß-APP. Results We developed a grading system based on histopathological characteristics to assess the overall damage of axonal injury. We found maximum histopathological changes in cases with prolonged stay. Corpus callosum showed maximum changes in both gradings. Curiously, we also detected axonal swellings with H&E staining. Usually neglected, the thalamus also showed significant histopathological and immunoreactive changes for sTBI. Conclusion Our study based on histopathological and ß-APP scoring system to define and identify DAI thus facilitates accurate diagnosis of DAI post mortem, which has forensic implications, and may further contribute toward survival and improvement of quality of life of sTBI patients.

Potential roles of polyunsaturated fatty acid-enriched diets in modulating social stress-like features.

Fish oil or its major constituents, namely omega-3 poly-unsaturated fatty acid (n3-PUFA), are popular supplements to improve neurogenesis, neuroprotection, and overall brain functions. Our objective was to probe the implications of fat enriched diet with variable PUFAs supplements in ameliorating social stress (SS). We fed mice on either of the three diet types, namely the n-3 PUFA-enriched diet (ERD, n3:n6= 7:1), a balanced diet (BLD, n3:n6= 1:1) or a standard lab diet (STD, n3:n6= 1:6). With respect to the gross fat contents, the customized special diets, namely ERD and BLD were extreme diet, not reflecting the typical human dietary composition. Aggressor-exposed SS (Agg-E SS) model triggered behavioral deficiencies that lingered for 6 weeks (6w) post-stress in mice on STD. ERD and BLD elevated bodyweights but potentially helped in building the behavioral resilience to SS. STD adversely affected the gene networks of brain transcriptomics associated with the cell mortality, energy homeostasis and neurodevelopment disorder. Diverging from the ERD's influences on these networks, BLD showed potential long-term benefits in combatting Agg-E SS. The gene networks linked to cell mortality and energy homeostasis, and their subfamilies, such as cerebral disorder and obesity remained at the baseline level of Agg-E SS mice on BLD 6w post-stress. Moreover, neurodevelopment disorder network and its subfamilies like behavioral deficits remained inhibited in the cohort fed on BLD 6w post Agg-E SS.

Severe, short-term sleep restriction reduces gut microbiota community richness but does not alter intestinal permeability in healthy young men.

Sleep restriction alters gut microbiota composition and intestinal barrier function in rodents, but whether similar effects occur in humans is unclear. This study aimed to determine the effects of severe, short-term sleep restriction on gut microbiota composition and intestinal permeability in healthy adults. Fecal microbiota composition, measured by 16S rRNA sequencing, and intestinal permeability were measured in 19 healthy men (mean ± SD; BMI 24.4 ± 2.3 kg/m2, 20 ± 2 years) undergoing three consecutive nights of adequate sleep (AS; 7-9 h sleep/night) and restricted sleep (SR; 2 h sleep/night) in random order with controlled diet and physical activity. α-diversity measured by amplicon sequencing variant (ASV) richness was 21% lower during SR compared to AS (P = 0.03), but α-diversity measured by Shannon and Simpson indexes did not differ between conditions. Relative abundance of a single ASV within the family Ruminococcaceae was the only differentially abundant taxon (q = 0.20). No between-condition differences in intestinal permeability or ß-diversity were observed. Findings indicated that severe, short-term sleep restriction reduced richness of the gut microbiota but otherwise minimally impacted community composition and did not affect intestinal permeability in healthy young men.

Outpatient Pharmacogenomic Screenings to Prevent Addiction, Overdose, and Suicide.

Point-of-care genetic testing for single nucleotide polymorphisms (SNPs) to improve psychiatric treatment in outpatient settings remains a challenge. The presence or absence of certain genomic alleles determines the activity of the encoded enzymes, which ultimately defines the individual's drug metabolism rate. Classification of poor metabolizers (PMs) and rapid/ultrarapid metabolizers (RMs/UMs) would facilitate personalization and precision of treatment. However, current pharmacogenomic (PGx) testing of multiple genes is comprehensive and requires quantitative analyses for interpretations. We recommend qualitative, fast-track, point-of-care screenings, which are one- or-two gene-based analyses, as a quick initial screening tool to potentially eliminate the need for an expensive quantitative send-out test, which is a costly and lengthy process. We speculate that these tests will be relevant in two major scenarios: 1) clinical psychiatry for treating disease states such as major depressive disorder (MDD) and posttraumatic stress disorder (PTSD), where trial and error is still the mainstay of drug selection and symptom management, a process that is associated with significant delay in optimizing individualized treatment and dose, and thus response; and 2) pain management, where quickly determining an effective level of analgesia while avoiding a toxic level can cause a drastic improvement in mental health.

Rate of shed of SARS COV-2 viral RNA from COVID-19 cadavers.

BACKGROUND: At what rate does the RNA of SARS CoV-2 shed from cadavers? Although, there have been numerous studies which have demonstrated the persistence of the virus on dead bodies, there is a lack of conclusive evidence regarding the variation of viral RNA content in cadavers. This has led to a knowledge gap regarding the safe handling/management of COVID-19 decedents, posing a barrier in forensic investigations. METHODS: In this study, we report the presence of RNA of SARS CoV-2 by real time RT-PCR, in nasopharyngeal swabs collected after death from two groups of bodies - one who died due to COVID-19 and the other who died due to other diagnoses. A prospective study on 199 corpses, who had tested positive for COVID-19 ante-mortem, was conducted at a tertiary care center. RNA testing was conducted at different time intervals (T1-T5). RESULTS: 112(56.3%) died primarily due to COVID-19 and 87(43.7%) died due to other diagnoses. 144(72.4%) were male and 55(27.6%) were female. A total of 115 (57.8%) tested positive for COVID-19 after death at different time points. The mean age was 50.7 ± 18.9 years and the length of hospitalization ranged from 1 to 50 days with a mean of 9.2 ± 7.6 days. Realtime RT-PCR positivity of SARS CoV-2 RNA decreases with time. CONCLUSION: We observed that real time RT-PCR positivity, indicating viral RNA detection, decreases with time. Therefore, it is advisable to follow appropriate COVID-19 precautions to carry out scientific studies, medico-legal investigations and mortuary services on suspected/confirmed COVID-19 corpses.

Systemic effects of BMP2 treatment of fractures on non-injured skeletal sites during spaceflight.

Unloading associated with spaceflight results in bone loss and increased fracture risk. Bone morphogenetic protein 2 (BMP2) is known to enhance bone formation, in part, through molecular pathways associated with mechanical loading; however, the effects of BMP2 during spaceflight remain unclear. Here, we investigated the systemic effects of BMP2 on mice sustaining a femoral fracture followed by housing in spaceflight (International Space Station or ISS) or on Earth. We hypothesized that in spaceflight, the systemic effects of BMP2 on weight-bearing bones would be blunted compared to that observed on Earth. Nine-week-old male mice were divided into four groups: 1) Saline+Earth; 2) BMP+Earth; 3) Saline+ISS; and 4) BMP+ISS (n = 10 mice/group, but only n = 5 mice/group were reserved for micro-computed tomography analyses). All mice underwent femoral defect surgery and were followed for approximately 4 weeks. We found a significant reduction in trabecular separation within the lumbar vertebrae after administering BMP2 at the fracture site of mice housed on Earth. In contrast, BMP2 treatment led to a significant increase in trabecular separation concomitant with a reduction in trabecular number within spaceflown tibiae. Although these and other lines of evidence support our hypothesis, the small sample size associated with rodent spaceflight studies limits interpretations. That said, it appears that a locally applied single dose of BMP2 at the femoral fracture site can have a systemic impact on distant bones, affecting bone quantity in several skeletal sites. Moreover, our results suggest that BMP2 treatment works through a pathway involving mechanical loading in which the best outcomes during its treatment on Earth occurred in the weight-bearing bones and in spaceflight occurred in bones subjected to higher muscle contraction.

Comparison of Transcriptional Signatures of Three Staphylococcal Superantigenic Toxins in Human Melanocytes.

Staphylococcus aureus, a gram-positive bacterium, causes toxic shock through the production of superantigenic toxins (sAgs) known as Staphylococcal enterotoxins (SE), serotypes A-J (SEA, SEB, etc.), and toxic shock syndrome toxin-1 (TSST-1). The chronology of host transcriptomic events that characterizes the response to the pathogenesis of superantigenic toxicity remains uncertain. The focus of this study was to elucidate time-resolved host responses to three toxins of the superantigenic family, namely SEA, SEB, and TSST-1. Due to the evolving critical role of melanocytes in the host's immune response against environmental harmful elements, we investigated herein the transcriptomic responses of melanocytes after treatment with 200 ng/mL of SEA, SEB, or TSST-1 for 0.5, 2, 6, 12, 24, or 48 h. Functional analysis indicated that each of these three toxins induced a specific transcriptional pattern. In particular, the time-resolved transcriptional modulations due to SEB exposure were very distinct from those induced by SEA and TSST-1. The three superantigens share some similarities in the mechanisms underlying apoptosis, innate immunity, and other biological processes. Superantigen-specific signatures were determined for the functional dynamics related to necrosis, cytokine production, and acute-phase response. These differentially regulated networks can be targeted for therapeutic intervention and marked as the distinguishing factors for the three sAgs.

Acute and Delayed Effects of Stress Eliciting Post-Traumatic Stress-Like Disorder Differentially Alters Fecal Microbiota Composition in a Male Mouse Model.

The association between the shift in fecal resident microbiome and social conflicts with long-term consequences on psychological plasticity, such as the development of post-traumatic stress disorder (PTSD), is yet to be comprehended. We developed an aggressor-exposed (Agg-E) social stress (SS) mouse model to mimic warzone-like conflicts, where random life-threatening interactions took place between naïve intruder mice and aggressive resident mice. Gradually these Agg-E mice developed distinct characteristics simulating PTSD-like aspects, whereas the control mice not exposed to Agg-E SS demonstrated distinct phenotypes. To further investigate the role of Agg-E SS on the resident microbiome, 16S rRNA gene sequencing was assayed using fecal samples collected at pre-, during, and post-SS time points. A time agonist shift in the fecal microbial composition of Agg-E mice in contrast to its controls suggested a persistent impact of Agg-E SS on resident microbiota. At the taxonomic level, Agg-E SS caused a significant shift in the time-resolved ratios of Firmicutes and Bacteroidetes abundance. Furthermore, Agg-E SS caused diverging shifts in the relative abundances of Verrucomicrobia and Actinobacteria. An in silico estimation of genomic potential identified a potentially perturbed cluster of bioenergetic networks, which became increasingly enriched with time since the termination of Agg-E SS. Supported by a growing number of studies, our results indicated the roles of the microbiome in a wide range of phenotypes that could mimic the comorbidities of PTSD, which would be directly influenced by energy deficiency. Together, the present work suggested the fecal microbiome as a potential tool to manage long-term effects of social conflicts, including the management of PTSD.

Glymphatics: A Transformative Development in Medical Neuroscience Relevant to Injuries in Military Central Nervous System.

INTRODUCTION: The glia-operated glymphatic system, analogous to but separate from the lymphatics in the periphery, is unique to brain and retina, where it is very closely aligned with the arteriolar system. This intimate relationship leads to a "blood vessel like" distribution pattern of glymphatic vessels in the brain. The spatial relationship of glymphatics, including their essential component aquaporin-4 with vascular pericytes of brain arterioles is critical to functionality and is termed "polarization". MATERIALS AND METHODS: We review the available literature on the factors affecting the resting state of glymphatics under normal conditions, including the important role of sleep in supporting normal glymphatic function (including waste removal) as well as the critical role of "polarization" under normal conditions. We then examine the effects of traumatic brain injury (TBI) or seizures on the glymphatic system and its state of "polarization". RESULTS: Injury, such as TBI, can disrupt polarization resulting in "depolarization" leading to brain edema. CONCLUSION: Damage to the glymphatic system might explain the brain edema so often seen following TBI or other insult. Moreover, similar damage should be expected in response to seizures, which can often be associated with chemical exposures as well as with TBI. Military operations, whether night operations or continuous operations, quite often impose limitations on sleep. As glymphatic function is sleep-dependent, sleep deprivation alone could compromise glymphatic function, as well, and might in addition, explain some of the well-known performance deficits associated with sleep deprivation. Possible effects of submarine and diving operations, chemical agents (including seizures), as well as high altitude exposure and other threats should be considered. In addition to the brain, the retina is also served and protected by the glymphatic system. Accordingly, the effect of military-related risks (e.g., exposure to laser or other threats) to retinal glymphatic function should also be considered. An intact glymphatic system is absolutely essential to support normal central nervous system functionality, including cognition. This effects a broad range of military threats on brain and retinal glymphatics should be explored. Possible preventive and therapeutic measures should be proposed and evaluated, as well.

Predicting fracture healing with blood biomarkers: the potential to assess patient risk of fracture nonunion.

Fracture non-union is a significant orthopaedic problem affecting a substantial number of patients yearly. Treatment of nonunions is devastating to patients and costly to the healthcare system. Unfortunately, the diagnosis of non-union is typically made in a reactionary fashion by an orthopaedic surgeon based on clinical assessment and radiographic features several months into treatment. For this reason, investigators have been trying to develop prediction algorithms; however, these have relied on population-based approaches and lack the predictive capability necessary to make individual treatment decisions. There is also a growing body of literature focussed on identifying blood biomarkers that are associated with non-union. This review describes the research that has been done in this area. Further studies of patient-centered, precision medicine approaches will likely improve fracture non-union diagnostic/prognostic capabilities.

Gene-metabolite networks associated with impediment of bone fracture repair in spaceflight.

Adverse effects of spaceflight on musculoskeletal health increase the risk of bone injury and impairment of fracture healing. Its yet elusive molecular comprehension warrants immediate attention, since space travel is becoming more frequent. Here we examined the effects of spaceflight on bone fracture healing using a 2 mm femoral segmental bone defect (SBD) model. Forty, 9-week-old, male C57BL/6J mice were randomized into 4 groups: 1) Sham surgery on Ground (G-Sham); 2) Sham surgery housed in Spaceflight (FLT-Sham); 3) SBD surgery on Ground (G-Surgery); and 4) SBD surgery housed in Spaceflight (FLT-Surgery). Surgery procedures occurred 4 days prior to launch; post-launch, the spaceflight mice were house in the rodent habitats on the International Space Station (ISS) for approximately 4 weeks before euthanasia. Mice remaining on the Earth were subjected to identical housing and experimental conditions. The right femur from half of the spaceflight and ground groups was investigated by micro-computed tomography (µCT). In the remaining mice, the callus regions from surgery groups and corresponding femoral segments in sham mice were probed by global transcriptomic and metabolomic assays. µCT confirmed escalated bone loss in FLT-Sham compared to G-Sham mice. Comparing to their respective on-ground counterparts, the morbidity gene-network signal was inhibited in sham spaceflight mice but activated in the spaceflight callus. µCT analyses of spaceflight callus revealed increased trabecular spacing and decreased trabecular connectivity. Activated apoptotic signals in spaceflight callus were synchronized with inhibited cell migration signals that potentially hindered the wound site to recruit growth factors. A major pro-apoptotic and anti-migration gene network, namely the RANK-NFκB axis, emerged as the central node in spaceflight callus. Concluding, spaceflight suppressed a unique biomolecular mechanism in callus tissue to facilitate a failed regeneration, which merits a customized intervention strategy.

Late Health Effects of Partial Body Irradiation Injury in a Minipig Model Are Associated with Changes in Systemic and Cardiac IGF-1 Signaling.

Clinical, epidemiological, and experimental evidence demonstrate non-cancer, cardiovascular, and endocrine effects of ionizing radiation exposure including growth hormone deficiency, obesity, metabolic syndrome, diabetes, and hyperinsulinemia. Insulin-like growth factor-1 (IGF-1) signaling perturbations are implicated in development of cardiovascular disease and metabolic syndrome. The minipig is an emerging model for studying radiation effects given its high analogy to human anatomy and physiology. Here we use a minipig model to study late health effects of radiation by exposing male Göttingen minipigs to 1.9-2.0 Gy X-rays (lower limb tibias spared). Animals were monitored for 120 days following irradiation and blood counts, body weight, heart rate, clinical chemistry parameters, and circulating biomarkers were assessed longitudinally. Collagen deposition, histolopathology, IGF-1 signaling, and mRNA sequencing were evaluated in tissues. Our findings indicate a single exposure induced histopathological changes, attenuated circulating IGF-1, and disrupted cardiac IGF-1 signaling. Electrolytes, lipid profiles, liver and kidney markers, and heart rate and rhythm were also affected. In the heart, collagen deposition was significantly increased and transforming growth factor beta-1 (TGF-beta-1) was induced following irradiation; collagen deposition and fibrosis were also observed in the kidney of irradiated animals. Our findings show Göttingen minipigs are a suitable large animal model to study long-term effects of radiation exposure and radiation-induced inhibition of IGF-1 signaling may play a role in development of late organ injuries.

Analysis of the effects of spaceflight and local administration of thrombopoietin to a femoral defect injury on distal skeletal sites.

With increased human presence in space, bone loss and fractures will occur. Thrombopoietin (TPO) is a recently patented bone healing agent. Here, we investigated the systemic effects of TPO on mice subjected to spaceflight and sustaining a bone fracture. Forty, 9-week-old, male, C57BL/6 J were divided into 4 groups: (1) Saline+Earth; (2) TPO + Earth; (3) Saline+Flight; and (4) TPO + Flight (n = 10/group). Saline- and TPO-treated mice underwent a femoral defect surgery, and 20 mice were housed in space ("Flight") and 20 mice on Earth for approximately 4 weeks. With the exception of the calvarium and incisor, positive changes were observed in TPO-treated, spaceflight bones, suggesting TPO may improve osteogenesis in the absence of mechanical loading. Thus, TPO, may serve as a new bone healing agent, and may also improve some skeletal properties of astronauts, which might be extrapolated for patients on Earth with restraint mobilization and/or are incapable of bearing weight on their bones.

Microdissection of Mouse Brain into Functionally and Anatomically Different Regions.

The brain is the command center for the mammalian nervous system and an organ with enormous structural complexity. Protected within the skull, the brain consists of an outer covering of grey matter over the hemispheres known as the cerebral cortex. Underneath this layer reside many other specialized structures that are essential for multiple phenomenon important for existence. Acquiring samples of specific gross brain regions requires quick and precise dissection steps. It is understood that at the microscopic level, many sub-regions exist and likely cross the arbitrary regional boundaries that we impose for the purpose of this dissection. Mouse models are routinely used to study human brain functions and diseases. Changes in gene expression patterns may be confined to specific brain areas targeting a particular phenotype depending on the diseased state. Thus, it is of great importance to study regulation of transcription with respect to its well-defined structural organization. A complete understanding of the brain requires studying distinct brain regions, defining connections, and identifying key differences in the activities of each of these brain regions. A more comprehensive understanding of each of these distinct regions may pave the way for new and improved treatments in the field of neuroscience. Herein, we discuss a step-by-step methodology for dissecting the mouse brain into sixteen distinct regions. In this procedure, we have focused on male mouse C57Bl/6J (6-8 week old) brain removal and dissection into multiple regions using neuroanatomical landmarks to identify and sample discrete functionally-relevant and behaviorally-relevant brain regions. This work will help lay a strong foundation in the field of neuroscience, leading to more focused approaches in the deeper understanding of brain function.