Cerebral Expression of Glial Fibrillary Acidic Protein, Ubiquitin Carboxy-Terminal Hydrolase-L1, and Matrix Metalloproteinase 9 After Traumatic Brain Injury and Secondary Brain Insults in Rats

Early vs Late Fixation of Extremity Fractures Among Adults With Traumatic Brain Injury

Importance

The optimal timing for fixation of extremity fractures after traumatic brain injury (TBI) remains controversial.

Objective

To investigate whether patients who underwent extremity fixation within 24 hours of TBI experienced worse outcomes than those who had the procedure 24 hours or more after TBI.

Design, Setting, and Participants

This cohort study used data from the Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) study. Patients 16 years or older with TBI who underwent internal extremity fixation met inclusion criteria. To compare outcomes, patients who underwent the procedure within 24 hours were propensity score matched with those who underwent it 24 hours or later. Patients were treated from December 9, 2014, to December 17, 2017. Data analysis was conducted between August 1, 2022, and December 25, 2023.

Main Outcomes and Measures

The primary outcome was an unfavorable functional status at 6 months (Glasgow Outcome Scale-Extended [GOSE] score ≤4).

Results

A total of 253 patients were included in this study. The median age was 41 (IQR, 27-57) years, and 184 patients (72.7%) were male. The median Injury Severity Score (ISS) was 41 (IQR, 27-49). Approximately half of the patients (122 [48.2%]) had a mild TBI while 120 (47.4%) had moderate to severe TBI. Seventy-four patients (29.2%) underwent an internal extremity fixation within 24 hours, while 179 (70.8%) had the procedure 24 hours or later. At 6 months, 86 patients (34.0%) had an unfavorable functional outcome. After propensity score matching, there were no statistically significant differences in unfavorable functional outcomes at 6 months (odds ratio [OR], 1.12 [95% CI, 0.51-1.99]; P = .77) in patients with TBI of any severity. Similar results were observed in patients with mild TBI (OR, 0.71 [95% CI, 0.22-2.29]; P = .56) and moderate to severe TBI (OR, 1.08 [95% CI, 0.32-3.70]; P = .90).

Conclusions and Relevance

The outcomes of extremity fracture fixation performed within 24 hours after TBI appear not to be worse than those of procedures performed 24 hours or later. This finding suggests that early fixation after TBI could be considered in patients with mild head injuries.

Matrix Metalloproteinase-9 inhibitors as therapeutic drugs for traumatic brain injury

Traumatic brain injury (TBI) is one of the leading causes of morbidity and mortality among young adults and the elderly. In the United States, TBI is responsible for around 30 percent of all injuries brought on by injuries in general. Vasogenic cerebral edema due to blood-brain barrier (BBB) dysfunction and the associated elevation of intracranial pressure (ICP) are some of the major causes of secondary injuries following traumatic brain injury. Matrix metalloproteinase-9 (MMP-9) is a therapeutic target for being an enzyme that degrades the proteins that make up a part of the microvascular basal lamina as well as inter-endothelial tight junctions of the blood-brain barrier. MMP-9-mediated BBB dysfunctions and the compromise of the BBB is a major pathway that leads the development of vasogenic cerebral edema, elevation of ICP, poor cerebral perfusion and brain herniation following traumatic brain injury. That makes MMP-9 an effective therapeutic target and endogenous or exogenous MMP-9 inhibitors as therapeutic drugs for preventing secondary brain damage after traumatic brain injury. Although our understanding of the mechanisms that underlie the primary and secondary stages of damage following a TBI has significantly improved in recent years, such information has not yet resulted in the successful development of novel pharmacological treatment options for traumatic brain injury. Recent pre-clinical and/or clinical studies have demonstrated that there are several compounds with specific or non-specific MMP-9 inhibitory properties either directly binding and inhibiting MMP-9 or by indirectly inhibiting MMP-9, with potential as therapeutic agents for traumatic brain injury. This article reviews the efficacy of several such medications and potential agents that include endogenous and exogeneous compounds that are at various levels of research and development. MMP-9-based therapeutic drug development has enormous potential in the pharmacological treatment of cerebral edema and/or neuronal injury resulting from traumatic brain injury.

Deep Learning-Based Segmentation of Morphologically Distinct Rat Hippocampal Reactive Astrocytes After Trimethyltin Exposure

As regulators of homeostasis, astrocytes undergo morphological changes after injury to limit the insult in central nervous system (CNS). Trimethyltin (TMT) is a known neurotoxicant that induces reactive astrogliosis in rat CNS. To evaluate the degree of reactive astrogliosis, the assessment relies on manual counting or semiquantitative scoring. We hypothesized that deep learning algorithm could be used to identify the grade of reactive astrogliosis in immunoperoxidase-stained sections in a quantitative manner. The astrocyte algorithm was created using a commercial supervised deep learning platform and the used training set consisted of 940 astrocytes manually annotated from hippocampus and cortex. Glial fibrillary acidic protein-labeled brain sections of rat TMT model were analyzed for astrocytes with the trained algorithm. Algorithm was able to count the number of individual cells, cell areas, and circumferences. The astrocyte algorithm identified astrocytes with varying sizes from immunostained sections with high confidence. Algorithm analysis data revealed a novel morphometric marker based on cell area and circumference. This marker correlated with the time-dependent progression of the neurotoxic profile of TMT. This study highlights the potential of using novel deep learning-based image analysis tools in neurotoxicity and pharmacology studies.

The effect of clopidogrel and aspirin on the severity of traumatic brain injury in a rat model

Traumatic Brain Injury (TBI) is one of the leading causes of death and disability worldwide. Aspirin (ASA) and clopidogrel (CLOP) are antiplatelet agents that inhibit platelet aggregation. They are implicated in worsening the intracerebral haemorrhage (ICH) risk post-TBI. However, antiplatelet drugs may also exert a neuroprotective effect post-injury. We determined the impact of aspirin and clopidogrel treatment, alone or in combination, on ICH and brain damage in an experimental rat TBI model. We assessed changes in platelet aggregation and measured serum thromboxane by enzyme immune assay. We also explored a panel of brain damage and apoptosis biomarkers by immunoblotting. Rats were treated with aspirin and/or clopidogrel for 48 h prior to TBI and sacrificed 48 h post-injury. In rats treated with antiplatelet agents prior to TBI, platelet aggregation was completely inhibited, and serum thromboxane was significantly decreased, compared to the TBI group without treatment. TBI increases UCHL-1 and GFAP, but decreases hexokinase expression compared to the non-injured controls. All groups treated with antiplatelet drugs prior to TBI had decreased UCH-L1 and GFAP serum levels compared to the TBI untreated group. Furthermore, the ASA and CLOP single treatments increased the hexokinase serum levels. We confirmed that αII-spectrin cleavage increased post-TBI, with the highest cleavage detected in CLOP-treated rats. Aspirin and/or clopidogrel treatment prior to TBI is a double-edged sword that exerts a dual effect post-injury. On one hand, ASA and CLOP single treatments increase the post-TBI ICH risk, with a further detrimental effect from the ASA + CLOP treatment. On the other hand, ASA and/or CLOP treatments are neuroprotective and result in a favourable profile of TBI injury markers. The ICH risk and the neuroprotection benefits from antiplatelet therapy should be weighed against each other to ameliorate the management of TBI patients.

Co-Expression Network Analysis of MicroRNAs and Proteins in Severe Traumatic Brain Injury: A Systematic Review

Traumatic brain injury (TBI) represents one of the leading causes of mortality and morbidity worldwide, placing an enormous socioeconomic burden on healthcare services and communities around the world. Survivors of TBI can experience complications ranging from temporary neurological and psychosocial problems to long-term, severe disability and neurodegenerative disease. The current lack of therapeutic agents able to mitigate the effects of secondary brain injury highlights the urgent need for novel target discovery. This study comprises two independent systematic reviews, investigating both microRNA (miRNA) and proteomic expression in rat models of severe TBI (sTBI). The results were combined to perform integrated miRNA-protein co-expression analyses with the aim of uncovering the potential roles of miRNAs in sTBI and to ultimately identify new targets for therapy. Thirty-four studies were included in total. Bioinformatic analysis was performed to identify any miRNA–protein associations. Endocytosis and TNF signalling pathways were highlighted as common pathways involving both miRNAs and proteins found to be differentially expressed in rat brain tissue following sTBI, suggesting efforts to find novel therapeutic targets that should be focused here. Further high-quality investigations are required to ascertain the involvement of these pathways and their miRNAs in the pathogenesis of TBI and other CNS diseases and to therefore uncover those targets with the greatest therapeutic potential.

The expression and clinical value of ubiquitin carboxyl-terminal hydrolase L1 in the blood of neonates with hypoxic ischemic encephalopathy

BACKGROUND

Neonatal hypoxic ischemic encephalopathy (HIE) can result in mental retardation due to the associated brain damage. Early identification of brain injury is vital for the prevention and treatment of brain damage in neonates. This study investigated the expression levels of serum ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) in neonates with HIE and its correlation with brain damage.

METHODS

From January 2019 to December 2020, 56 cases of neonatal patients with HIE were selected as the observation group, and 60 cases of healthy newborns delivered in our hospital during the same period were selected as the control group. Blood samples were obtained from neonates and the serum expression of UCH-L1 was detected by enzyme-linked immunosorbent assays (ELISAs). The relationship between UCH-L1 and neonatal prognosis and clinical features was analyzed.

RESULTS

Compared with the healthy control group, the serum levels of UCH-L1 in the observation group was significantly higher (2.28±1.21 vs. 0.81±0.39 ng/mL, P=0.000). Furthermore, at 6 hours after birth, the serum levels of UCH-L1 were significantly higher in neonates with moderate to severe HIE compared to patients with mild HIE (2.92±0.80 and 1.76±0.72 ng/mL, respectively, P=0.000). Pearson correlation analysis showed that the expression levels of UCH-L1 were negatively correlated with the development quotient (DQ), intelligence index (MI), and the Neonatal Behavioral Neurological Assessment (NBNA) score of HIE newborns (P<0.05).

CONCLUSIONS

The level of UCH-L1 protein expression is elevated in the serum of newborns with HIE, and this may have a certain clinical value in predicting the intelligence of children.