Recombinant Human Milk Fat Globule-Epidermal Growth Factor 8 Attenuates Microthrombosis after Subarachnoid Hemorrhage in Rats

ERBB1 alleviates secondary brain injury induced by experimental intracerebral hemorrhage in rats by modulating neuronal death via PLC-γ/PKC pathway

AIMS

Intracerebral hemorrhage (ICH) is a disease with high rates of disability and mortality. The role of epidermal growth factor receptor 1 (ERBB1) in ICH was elucidated in this study.

METHODS

ICH model was constructed by injecting autologous arterial blood into the right basal ganglia. The protein level of ERBB1 was detected by western blot analysis. To up- and downregulation of ERBB1 in rats, intraventricular injection of a lentivirus overexpression vector of ERBB1 and AG1478 (a specific inhibitor of ERBB1) was used. The cell apoptosis, neuronal loss, and pro-inflammatory cytokines were assessed by TUNEL, Nissl staining, and ELISA. Meanwhile, behavioral cognitive impairment of ICH rats was evaluated after ERBB1-targeted interventions.

RESULTS

ERBB1 increased significantly in brain tissue of ICH rats. Overexpression of ERBB1 remarkably reduced cell apoptosis and neuronal loss induced by ICH, as well as pro-inflammatory cytokines and oxidative stress. Meanwhile, the behavioral and cognitive impairment of ICH rats were alleviated after upregulation of ERBB1; however, the secondary brain injury (SBI) was aggravated by AG1478 treatment. Furthermore, the upregulation of PLC-γ and PKC in ICH rats was reversed by AG1478 treatment.

CONCLUSIONS

ERBB1 can improve SBI and has a neuroprotective effect in experimental ICH rats via PLC-γ/PKC pathway.

The Role of Neutrophil Extracellular Traps in Early Microthrombosis and Brain Injury After Subarachnoid Hemorrhage in Mice

Microthrombosis plays an important role in secondary brain injury after experimental subarachnoid hemorrhage (SAH), but the specific mechanism of microthrombosis remains unclear. The purpose of this study was to investigate the role of neutrophil extracellular traps (NETs) in microthrombosis after SAH. SAH was induced in male C57BL/6 mice using an endovascular perforation technique. The marker protein of NETs, citrullinated histone H3 (CitH3), was significantly elevated in the cerebral cortex after SAH, and was co-labeled with microthrombi. Both depletion of neutrophils by anti-Ly6G antibody and DNase I treatment significantly reduced the formation of NETs and microthrombi, and ameliorated neurological deficits, brain edema, BBB disruption, and neuronal injury at 24 h after SAH induction. Cerebral hypoperfusion in the first hours after SAH is a major determinant of poor neurological outcome; in this study, we found that DNase I treatment significantly improved the restoration of early cortical perfusion after SAH. In addition, DNase I treatment also significantly attenuated cerebrospinal fluid (CSF) flow after SAH, which was associated with the diffusion barrier caused by microthrombi in the paravascular space after SAH. In conclusion, NETs are associated with early microthrombosis after SAH; they may be a novel therapeutic target for early brain injury (EBI) after SAH.

Effect of Recombinant Human Epidermal Growth Factor Associated with Conventional Drug Therapy on the Dry Eye Symptom Score in Patients with Dry Eyes after Cataract Surgery: A Systematic Review and Meta-Analysis

Objective

This study aimed to systematically assess the effect of recombinant human epidermal growth factor (rhEGF) associated with conventional drugs on the score of dry eye symptoms in patients with dry eyes after cataract surgery.

Methods

The online database was searched for the clinical controlled trials of rhEGF associated with conventional drugs in the therapy of dry eyes after cataract surgery. Until now, the retrieval timeframe is based on the establishment of the database. Separately, two researchers extracted the data. The bias risk of each included literature was assessed.

Results

Eight clinical controlled studies were finally included, with 878 samples. The success rate of the study group was greatly higher, and the difference was statistically significant (P < 0.05). The fluorescein staining (FL) score of the research group after treatment was lower, and the difference was statistically significant (P < 0.05). Compared with the control group, the tear break up time (BUT) of the study group after treatment was notably prolonged. The dry eye symptom score of the research group after treatment was notably lower, and the difference was statistically significant (P < 0.05).

Conclusion

Sodium hyaluronate associated with rhEGF eye drops is successful to treat xerophthalmia after cataract operation. It successfully promotes corneal healing, promotes tear film stability, and increases basic tear secretion. This treatment scheme is worth popularizing and applying in clinics.

DCI after Aneurysmal Subarachnoid Hemorrhage Is Related to the Expression of MFG-E8

Objective

To explore the predictive value of milk fat globule epidermal growth factor 8 (MFG-E8) in the occurrence of delayed cerebral ischemia (DCI) after an aneurysmal subarachnoid hemorrhage (aSAH).

Methods

We recruited 32 patients with aSAH as the case group and 24 patients with unruptured aneurysms as the control group. Serum MFG-E8 levels were measured by western blot and enzyme-linked immunosorbent assay. We analyzed the relationship between MFG-E8 levels and the risk of DCI.

Results

The levels of serum MFG-E8 in the case group (mean = 11160.9 pg/mL) were significantly higher than those in the control group (mean = 3081.0 pg/mL, p < 0.001). MFG-E8 levels highly correlated with the World Federation of Neurosurgical Societies (WFNS) and modified Fisher scores (r = -0.691 and - 0.767, respectively, p < 0.001). In addition, MFG-E8 levels in patients with DCI (5882.7 ± 3162.4 pg/mL) were notably higher than those in patients without DCI (15818.2 ± 3771.6 pg/mL, p < 0.001). A receiver operating characteristic curve showed that the occurrence of DCI could effectively be predicted by MFG-E8 (area under the curve = 0.976, 95%CI = 0.850-1.000). Kaplan-Meier survival analysis showed a remarkable decrease in the incidence of DCI in case group individuals with high levels of MFG-E8 (≥11160.9 pg/mL, p < 0.001).

Conclusion

MFG-E8 may be a useful predictive marker for DCI after an aSAH and could be a promising surrogate end point.

MFGE8 decreased neuronal apoptosis and neuroinflammation to ameliorate early brain injury induced by subarachnoid hemorrhage through the inhibition of HMGB1

AIM

Both MFGE8 and HMGB1 were vital players for aneurysmal subarachnoid hemorrhage. However, whether HMGB1 was served as the downstream target of MFGE8 was unknown. To test this new mechanism, we performed the SAH model in rats.

METHOD

All treatments were injected intraventricularly into the right lateral ventricles. SAH grade, brain water content, and neurological function scores were evaluated. HMGB1 expression was studied by double immunofluorescence staining. HE and Nissl's staining were performed to observe the pathological change. Inflammatory factors were measured by ELISA method.

RESULTS

High expression of MFGE8 could improve neurological function and reduce the brain edema and pro-inflammatory factors. Injection of rhMFGE8 inhibited HMGB1. To further verify the regulation of MFGE8 in HMGB1, we used rhHMGB1 and glycyrrhizin, and the results indicated MFGE8 produced excellent effect on SAH rats via inhibiting HMGB1.

CONCLUSION

In a word, MFGE8 improved EBI caused by SAH, depending on HMGB1 that was the potential mechanism.

PTEN and AKT/GSK-3β/CRMP-2 signaling pathway are involved in neuronal apoptosis and axonal injury in early brain injury after SAH in rats

In early brain injury (EBI) after subarachnoid hemorrhage (SAH), white matter (WM) axonal injury plays a key role in the prognosis of the disease. The purpose of this study was to investigate the effects of phosphatase and tensin homolog deleted on chromosome ten (PTEN) on axonal injury and neuronal apoptosis post-SAH in rats and to find its underlying mechanism. Adeno-associated virus was injected into the lateral ventricle to suppress or promote PTEN. Neural function post-SAH in animals was determined by the modified Garcia score, beam balance, and Rotarod test, and the blood–brain barrier disruption was assessed by the brain water content. Axonal injury post-SAH was observed by TEM and determined by IF, and neuron apoptosis was measured by TUNEL staining. The mechanism was analyzed by Western blot to detect p-PTEN/PTEN, p-AKT/AKT, p-GSK-3β/GSK-3β, p-CRMP-2/CRMP-2, axonal injury marker β-APP and pro- and anti-apoptosis proteins, including Bax and Bcl-2, expression. We found 1. After knocking down PTEN, neuronal apoptosis and axonal injury were alleviated, and nerve function and blood–brain barrier were protected; accordingly, after overexpression of PTEN, neuronal apoptosis and axon damage were aggravated, and nerve function damage and blood–brain barrier damage were increased. 2. PTEN and AKT/GSK-3β/CRMP-2 pathway were jointly involved in regulating neuronal apoptosis and WM axon injury after SAH. According to our research, PTEN was a negative factor of EBI, and together with the AKT/GSK-3β/CRMP-2 signaling pathway aggravates neuronal apoptosis and WM axon damage after SAH. Inhibition of PTEN expression may become a new target for SAH treatment.

An Update on Antioxidative Stress Therapy Research for Early Brain Injury After Subarachnoid Hemorrhage

The main reasons for disability and death in aneurysmal subarachnoid hemorrhage (aSAH) may be early brain injury (EBI) and delayed cerebral ischemia (DCI). Despite studies reporting and progressing when DCI is well-treated clinically, the prognosis is not well-improved. According to the present situation, we regard EBI as the main target of future studies, and one of the key phenotype-oxidative stresses may be called for attention in EBI after laboratory subarachnoid hemorrhage (SAH). We summarized the research progress and updated the literature that has been published about the relationship between experimental and clinical SAH-induced EBI and oxidative stress (OS) in PubMed from January 2016 to June 2021. Many signaling pathways are related to the mechanism of OS in EBI after SAH. Several antioxidative stress drugs were studied and showed a protective response against EBI after SAH. The systematical study of antioxidative stress in EBI after laboratory and clinical SAH may supply us with new therapies about SAH.

MFGE8 mitigates brain injury in a rat model of SAH by maintaining vascular endothelial integrity via TIGβ5/PI3K/CXCL12 signaling

Leaked blood components, injured endothelial cells, local inflammatory response and vasospasm may converge to promote microthrombosis following subarachnoid hemorrhage (SAH). Previously, we showed that the milk fat globule-epidermal growth factor 8 (MFGE8) can mitigate SAH-induced microthrombosis. This present study was aimed to explore the molecular pathway participated in MFGE8-dependent protection on vascular endothelium. Immunofluorescence, immunoblot and behavioral tests were used to determine the molecular partner and signaling pathway mediating the effect of MFGE8 in vascular endothelium in rats with experimental SAH and controls, together with the applications of RNA silencing and pharmacological intervention methods. Relative to control, recombinant human MFGE8 (rhMFGE8) treatment increased 5-bromo-2'-deoxyuridine (BrdU) labeled new endothelial cells, reduced TUNUL-positive endothelial cells and elevated the expression of phosphatidylinositol 3-kinase (PI3K) and chemokine (C-X-C motif) ligand 12 (CXCL12), in the brains of SAH rats. These effects were reversed by MFGE8 RNA silencing, as well as following cilengitide and wortmannin intervention. These results suggest that MFGE8 promotes endothelial regeneration and mitigates endothelial DNA damage through the activation of the TIGβ5/PI3K/CXCL12 signaling pathway.