Hyperbaric Oxygen Therapy Reduces the Traumatic Brain Injury-Mediated Neuroinflammation Through Enrichment of Prevotella Copri in the Gut of Male Rats.

BACKGROUND: Gastrointestinal dysfunction frequently occurs following traumatic brain injury (TBI) and significantly increases posttraumatic complications. TBI can lead to alterations in gut microbiota. The neuroprotective effects of hyperbaric oxygen (HBO) have not been well recognized after TBI. The study''s aim was to investigate the impact of HBO on TBI-induced dysbiosis in the gut and the pathological changes in the brain following TBI. METHODS: Anesthetized male Sprague-Dawley rats were randomly assigned to three groups: sham surgery plus normobaric air (21% oxygen at 1 atmospheres absolute), TBI (2.0 atm) plus normobaric air, and TBI (2.0 atm) plus HBO (100% oxygen at 2.0 atmospheres absolute) for 60 min immediately after TBI, 24 h later, and 48 h later. The brain injury volume, tumor necrosis factor-α expression in microglia and astrocytes, and neuronal apoptosis in the brain were subsequently determined. The V3-V4 regions of 16S ribosomal rRNA in the fecal samples were sequenced, and alterations in the gut microbiome were statistically analyzed. All parameters were evaluated on the 3rd day after TBI. RESULTS: Our results demonstrated that HBO improved TBI-induced neuroinflammation, brain injury volume, and neuronal apoptosis. HBO appeared to increase the abundance of aerobic bacteria while inhibiting anaerobic bacteria. Intriguingly, HBO reversed the TBI-mediated decrease in Prevotella copri and Deinococcus spp., both of which were negatively correlated with neuroinflammation and brain injury volume. TBI increased the abundance of these gut bacteria in relation to NOD-lik0065 receptor signaling and the proteasome pathway, which also exhibited a positive correlation trend with neuro inflammation and apoptosis. The abundance of Prevotella copri was negatively correlated with NOD-like receptor signaling and the Proteasome pathway. CONCLUSIONS: Our study demonstrated how the neuroprotective effects of HBO after acute TBI might act through reshaping the TBI-induced gut dysbiosis and reversing the TBI-mediated decrease of Prevotella copri.

New diagnosis of cancer in mild and moderate/severe traumatic brain injury patients in a 12-year population-based study.

BACKGROUND: Traumatic brain injury (TBI) has been reported as a risk factor for brain cancer development. However, the magnitude of the impact of TBI on systemic cancer development has not been clarified. METHODS: A retrospective longitudinal cohort study was conducted using the Taiwan Longitudinal Health Insurance Database between January 2000 and December 2011. A total of 35,306 patients were initially enrolled, and 14,795 patients with mild TBI and 14,795 patients with moderate/severe TBI were matched using the National Health Insurance Research Database in Taiwan. The Cox proportional hazard regression model was used to estimate the hazard ratio (HR) of TBI adjusted for potential confounding factors. RESULTS: After matching, the results showed that patients with moderate/severe TBI had a high mortality rate (17.7% vs. 10.4%) and shorter time interval from TBI to death (mean 3.6 years vs. 5.8 years). No differences were observed in cancer incidence (4.1% vs. 4.1%) or risk factors for mortality between mild and moderate/severe TBI patients. However, patients aged between 46 and 55 years, female patients, and patients with pre-existing renal disease had a significant higher cancer incidence risk in moderate/severe TBI compared with mild TBI patients. The top 15 most common cancers showed that mild TBI patients had a higher percentage of head and neck cancer. The overall mortality rate in all TBI patients diagnosed with cancer was about 50%, and the cancer-specific mortality is approximately 85% in death of TBI patients with cancer. CONCLUSIONS: We concluded that the incidence risk of a new cancer diagnosis and mortality risk of TBI patients with cancer between the mild TBI and moderate/severe TBI patients were not significantly different.

Ceftriaxone therapy attenuates brain trauma in rats by affecting glutamate transporters and neuroinflammation and not by its antibacterial effects.

BACKGROUND: Ceftriaxone is a ß-lactam antibiotic used to treat central nervous system infections. Whether the neuroprotective effects of ceftriaxone after TBI are mediated by attenuating neuroinflammation but not its antibacterial actions is not well established. METHODS: Anesthetized male Sprague-Dawley rats were divided into sham-operated, TBI + vehicle, and TBI + ceftriaxone groups. Ceftriaxone was intraperitoneally injected at 0, 24, and 48 h with 50 or 250 mg/kg/day after TBI. During the first 120 min after TBI, we continuously measured heart rate, arterial pressure, intracranial pressure (ICP), and cerebral perfusion pressure. The infarct volume was measured by TTC staining. Motor function was measured using the inclined plane. Glutamate transporter 1 (GLT-1), neuronal apoptosis and TNF-α expression in the perilesioned cortex were investigated using an immunofluorescence assay. Bacterial evaluation was performed by Brown and Brenn's Gram staining. These parameters above were measured at 72 h after TBI. RESULTS: Compared with the TBI + vehicle group, the TBI + ceftriaxone 250 mg/kg group showed significantly lower ICP, improved motor dysfunction, reduced body weight loss, decreased infarct volume and neuronal apoptosis, decreased TBI-induced microglial activation and TNF-α expression in microglia, and increased GLT-1 expression in neurons and microglia. However, the grades of histopathological changes of antibacterial effects are zero. CONCLUSIONS: The intraperitoneal injection of ceftriaxone with 250 mg/kg/day for three days may attenuate TBI by increasing GLT-1 expression and reducing neuroinflammation and neuronal apoptosis, thereby resulting in an improvement in functional outcomes, and this neuroprotective effect is not related to its antibacterial effects.

The neuroprotective effects of AMN082 on neuronal apoptosis in rats after traumatic brain injury.

BACKGROUND: The aim of this study was to investigate whether AMN082 exerts its neuroprotective effect by attenuating glutamate receptor-associated neuronal apoptosis and improving functional outcomes after traumatic brain injury (TBI). METHODS: Anesthetized male Sprague-Dawley rats were divided into the sham-operated, TBI + vehicle, and TBI + AMN082 groups. AMN082 (10 mg/kg) was intraperitoneally injected 0, 24, or 48 h after TBI. In the 120 min after TBI, heart rate, mean arterial pressure, intracranial pressure (ICP), and cerebral perfusion pressure (CPP) were continuously measured. Motor function, the infarct volume, neuronal nitrosative stress-associated apoptosis, and N-methyl-D-aspartate receptor 2A (NR2A) and NR2B expression in the pericontusional cortex were measured on the 3rd day after TBI. RESULTS: The results showed that the AMN082-treated group had a lower ICP and higher CPP after TBI. TBI-induced motor deficits, the increase in infarct volume, neuronal apoptosis, and 3-nitrotyrosine and inducible nitric oxide synthase expression in the pericontusional cortex were significantly improved by AMN082 therapy. Simultaneously, AMN082 increased NR2A and NR2B expression in neuronal cells. CONCLUSIONS: We concluded that intraperitoneal injection of AMN082 for 3 days may ameliorate TBI by attenuating glutamate receptor-associated nitrosative stress and neuronal apoptosis in the pericontusional cortex. We suggest that AMN082 administration in the acute stage may be a promising strategy for TBI.

The Short-Term Effects of Isolated Traumatic Brain Injury on the Heart in Experimental Healthy Rats.

BACKGROUND: To date, cardiac dysfunction after traumatic brain injury (TBI) has not been consistent. In this study, we hypothesized that TBI may play a role in the development of new-onset cardiac dysfunction in healthy experimental rats. MATERIALS AND METHODS: Anesthetized healthy male Sprague-Dawley rats were divided into two groups: a sham-operated control group and a TBI group. The brain was injured with 2.4 atm percussion via a fluid percussion injury model. During the 120 min after TBI, we continuously measured brain parameters, including intracranial pressure (ICP) and cerebral perfusion pressure (CPP), and cardiac parameters, such as heart rate (HR), inter-ventricular septum dimension (IVSD), left ventricular internal dimension diastole (LVIDd), end-diastolic volume (EDV), ejection fraction (EF), fractional shortening (FS), and LV mass diastole (LVd mass) by cardiac echo. On days 1, 3, 7, and 14 after TBI, the brain damage volume was evaluated with triphenyltetrazolium chloride; the physiological parameters of the heart, including HR, IVSd, LVIDd, EDV, EF, FS, and LVd mass, were evaluated with cardiac echo; the morphology of cardiomyocytes was examined by hematoxylin and eosin (HE) and Masson trichrome staining; and the biomarkers of cardiac injury troponin I and B-type natriuretic peptide (BNP) were also examined. RESULTS: Compared to sham-operated controls, the TBI groups had higher ICP, lower CPP, and higher brain neuronal apoptosis and infarction contusion volume. The impact of TBI on heart function showed hyperdynamic response trends in IVSd, LVIDd, EDV, EF, FS, and LVd mass within 30 min after TBI; however, EF and FS exhibited eventual decreasing trends. Simultaneously, the values of the biomarkers troponin I and BNP were within normal limits, and HE and Mass trichrome staining revealed no significant differences between the sham-operated control group and the TBI group. CONCLUSIONS: Our results suggest that TBI due to 2.4 atm fluid percussion injury in healthy experimental rats may cause significant damage to the brain and affect the heart function as investigated by cardiac echo but not as investigated by HE and Masson trichrome stainings or troponin I and BNP evaluation.

FOUR Score Predicts Early Outcome in Patients After Traumatic Brain Injury.

BACKGROUND: The aim of the study was to determine whether the Full Outline of UnResponsiveness (FOUR) score, which includes eyes opening (E), motor function (M), brainstem reflex (B), and respiratory pattern (R), can be used as an alternate method to the Glasgow Coma Scale (GCS) in predicting intensive care unit (ICU) mortality in traumatic brain injury (TBI) patients. METHODS: From January 2015 to June 2015, patients with isolated TBI admitted to the ICU were enrolled. Three advanced practice nurses administered the FOUR score, GCS, Acute Physiology and Chronic Health Evaluation II (APACHE II), and Therapeutic Intervention Scoring System (TISS) concurrently from ICU admissions. The endpoint of observation was mortality when the patients left the ICU. Data are presented as frequency with percentages, mean with standard deviation, or median with interquartile range. Each measurement tool used area under the receiver operating characteristic curve to compare the predictive power between these four tools. In addition, the difference between survival and death was estimated using the Wilcoxon rank sum test. RESULTS: From 55 TBI patients, males (72.73 %) were represented more than females, the mean age was 63.1 ± 17.9, and 19 of 55 observations (35 %) had a maximum FOUR score of 16. The overall mortality rate was 14.6 %. The area under the receiver operating characteristic curve was 74.47 % for the FOUR score, 74.73 % for the GCS, 81.78 % for the APACHE II, and 53.32 % for the TISS. The FOUR score has similar predictive power of mortality compared to the GCS and APACHE II. Each of the parameters-E, M, B, and R-of the FOUR score showed a significant difference between mortality and survival group, while the verbal and eye-opening components of the GCS did not. CONCLUSION: Having similar predictive power of mortality compared to the GCS and APACHE II, the FOUR score can be used as an alternative in the prediction of early mortality in TBI patients in the ICU.

Pretreatment with Lovastatin Improves Depression-Like Behavior After Traumatic Brain Injury Through Activation of the AMPK Pathway.

BACKGROUND: The beneficial effect of pretreatment with statins on traumatic brain injury (TBI)-induced depression and anxiety and its mechanism of action remain unclear. In this study, we combined epidemiological and experimental animal data to clarify this issue. METHODS: We used the Taiwan National Health Insurance database to identify patients who were diagnosed with TBI from 2000 to 2013 and compared patients with and without statin treatment matched by age, sex, and underlying comorbidities in a 1:1 ratio. The risk of developing depression and/or anxiety was compared between patients with and without a statin using Cox proportional hazards regression. We also used a rat model to assess the effect of lovastatin pretreatment on neurobehavioral and neuropathological changes following TBI. RESULTS: The risk of developing depression was lower in the 41,803 patients in the statin cohort than nonstatin cohort (adjusted hazard ratio, 0.91 [95% confidence interval, 0.83-0.99]). In animal models, the lovastatin group had significantly reduced infarct volume, decreased immobility time and latency to eat, a reduced number of Fluoro- Jade-positive cells and levels of glial fibrillary acidic protein and tumor necrosis factor-alpha, and increased adenosine monophosphate -activated protein kinase (AMPK) and its upstream kinase liver kinase B1 in the hippocampal dentate gyrus. These effects were blocked in AMPK inhibitor-pretreated TBI rats. CONCLUSIONS: Our epidemiological data showed that a decreased risk of depression was associated with statin pretreatment, which was supported by an animal study. The underlying mechanism for this appears to involve AMPK activation in the statin pretreatment-induced alleviation of TBI.