A novel rat model of chronic subdural hematoma: Induction of inflammation and angiogenesis in the subdural space mimicking human-like features of progressively expanding hematoma

Vitamin D accelerates the subdural hematoma clearance through improving the meningeal lymphatic vessel function

Subdural hematoma (SDH) drains into the extracranial lymphatic system through the meningeal lymphatic vessels (mLVs) but the formation of SDH impairs mLVs. Because vitamin D (Vit D) can protect the endothelial cells, we hypothesized that Vit D may enhance the SDH clearance. SDH was induced in Sprague-Dawley rats and treated with Vit D or vehicle. Hematoma volume in each group was measured by H&E staining and hemoglobin quantification. Evans blue (EB) quantification and red blood cells injection were used to evaluated the drainage of mLVs. Western blot analysis and immunofluorescence were conducted to assess the expression of lymphatic protein markers. We also examined the inflammatory factors levels in subdural space by ELISA. Vit D treatment significantly reduced SDH volume and improved the drainage of SDH to cervical lymph nodes. The structure of mLVs in SDH rats were protected by Vit D, and the expressions of LYVE1, PROX1, FOXC2, and VE-cadherin were increased after Vit D treatment. The TNF-α, IL-6, and IL-8 levels were reduced in Vit D group. In vitro, Vit D also increased the VE-cadherin expression levels under inflammation. Vit D protects the structure of mLVs and enhances the absorption of SDH, partly by the anti-inflammatory effect of Vit D.

Chronic subdural hematoma: What precisely are we treating?

Subdural hematoma (SDH) refers to the collection of blood between the dura matter and the arachnoid membrane. Advancements in imaging technology have enabled the categorization of SDH based on specific imaging characteristics, causative factors, and the onset of symptoms. Given that the prognosis of SDHs varies significantly and is contingent upon the size and chronicity of the hemorrhage, a comprehensive understanding of its subtypes may carry crucial treatment implications. For example, an acute SDH classically results from severe traumatic brain injury and appears as a homogenous, crescent-shaped hyperdense extra-axial collection. If not treated, over the course of 1-3 weeks, this hematoma will evolve into a sub-acute phenotype as a consequence of subdural effusion and demonstrate mixed-density hemorrhage on imaging. Chronic SDH (cSDH) becomes the end result of an untreated SDH, with neo-membranization and neo-angiogenesis from branches of the middle meningeal artery driving a mass-like growth pattern. This review article aims to elucidate the complex anatomical features of the end-stage cSDH, with a particular focus on reconceptualization of this entity based on its mass-like growth patterns, and how this is driving a shift towards endovascular treatment.

A nomogram for predicting the possibility of effusion deterioration in patients with traumatic subdural effusion

BACKGROUND

Traumatic subdural effusion (TSDE) may increase progressively or evolve into chronic subdural hematoma. These events, defined as deterioration of the effusion, often require close observation or even surgical treatment. The aim of our study was to develop and validate a nomogram for predicting the possibility of an effusion deteriorating in patients with TSDE based on the available clinical characteristics.

METHODS

Clinical data from 78 patients with TSDE were retrospectively analyzed. All patients were admitted from January 2019 to May 2022. Logistic regression was applied to the data to screen for independent predictors of effusion deterioration within six months; then, a predictive nomogram model was established in R language. The consistency, predictive accuracy and clinical utility of the model were evaluated with the C-index, calibration plots, ROC curves and decision curve analysis (DCA). Furthermore, we performed internal validation using a bootstrap approach to assess the effectiveness of the model.

RESULTS

Time of effusion after trauma, maximum thickness of the effusion, CT value of the effusion as well as the use of atorvastatin were identified as predictors in the nomogram. The predictive model was well calibrated and demonstrated good discrimination (C-index: 0.893). The AUC of the model was 0.893 (95% CI: 0.824-0.962), and the modified C-index (0.865) indicated excellent performance in the internal validation. In addition, DCA revealed that the nomogram had clinical value.

CONCLUSIONS

This predictive model can effectively assess the risk of effusion deterioration in TSDE patients within six months and identify high-risk patients early.

Immunoexpression of MMP-8 and MMP-9 in chronic subdural hematoma

To determine the possible role of matrix metallopeptidase (MMP)-8 and MMP-9 in the development of chronic subdural hematoma (CSDH), we investigated their expression in CSDH. In our previous study, we analyzed hematoma fluid and peripheral blood of 83 patients with CSDH, including 17 postoperative patients. Based on these results, we included 50 people in the normal group and analyzed 20 markers in the peripheral blood of each person. In order to identify representative markers, it was assessed by using overall differential gene expression. The concentration of MMP-8 was significantly higher in the normal group than that in the preoperative and postoperative groups. The concentration of MMP-9 was significantly lower in the normal group than in both preoperative and postoperative groups. Immunohistochemistry confirmed the expression of MMP-8 and MMP-9 in CSDH membranes. In conclusion, our results provide evidence of the expression of MMP-8 and MMP-9 in CSDH. In addition, the expression of MMP-8 and MMP-9 suggests angiogenesis in CSDH formation.

Serum Levels of MMP-8 and MMP-9 as Markers in Chronic Subdural Hematoma

Chronic subdural hematoma (CSDH) is a common neurological disease that involves the collection of blood products in the subdural space. The progression of CSDH is an angiogenic and inflammatory process, but the multifactorial mechanisms underlying CSDH are still not fully understood. We aimed to identify one or more factors that may play an important role in the development of CSDH. We enrolled 83 patients with CSDH, including 17 postoperative patients, and analyzed 20 markers in the hematoma fluid and peripheral blood of each patient. Overall differential gene expression was examined to identify the representative markers. The concentration of MMP-8 was significantly lower in the postoperative group than in the preoperative group. The concentration of MMP-9 was significantly higher in the postoperative group than in the preoperative group. These findings indicate that MMP-8 and MMP-9 may play important roles in the pathophysiology of CSDH. Understanding the pathways associated with CSDH may provide insights for improving disease outcomes.

Atorvastatin combined with dexamethasone promote hematoma absorption in an optimized rat model of chronic subdural hematoma

Previous studies found that atorvastatin and dexamethasone were effective in promoting the absorption of chronic subdural hematoma. In this study, we aimed to investigate the effect of pharmacotherapy in an optimized rat model of chronic subdural hematoma. Rat model of chronic subdural hematoma via a bEnd.3 cell and Matrigel mix was established and dynamic changes in different drug treatment groups were tested. The hematoma gradually increased, peaked on the fifth day (263.8±52.85 μl), and was completely absorbed in two weeks. Notably, Kruppelle-like factor 2 expression was significantly decreased with increasing hematoma volume, and then increased in the repair period. The expression of IL-10 was increased and peaked on 7 days, and then decreased at 14 days. The dynamic trends of IL-6, IL-8, MMP-9, and VEGF were also increased first and then decreased. Both monotherapy and the combined treatment by atorvastatin and dexamethasone could counteract the inflammatory activities, decrease hematoma permeability, and improve hematoma absorption, however, most prominent in combined group. The combined treatment could more effectively increase Kruppelle-like factor 2 and ZO-1 expression, attenuate the expression of NF-κb. Most importantly, the combined treatment enhanced the neural functional prognosis and reduced the mortality of chronic subdural hematoma rats. According to our results, the combined treatment could more effectively attenuate inflammatory. And it could also enhance angiogenic activities which could promote the stability of local function and structure of the hematoma cavity, reduce the hematoma volume and improve the outcomes of rats with chronic subdural hematoma than single treatments in the optimized chronic subdural hematoma model.

History and current progress of chronic subdural hematoma

Chronic subdural hematoma (CSDH) is characterized by an encapsulated collection of old blood. Although CSDH has become the most frequent pathologic entity in daily neurosurgical practice, there are some unresolved research questions. In particular, the causes and recurrent risk factors of CSDH remain as an object of debate. The split of the dural border layer forms a few tiers of dural border cells over the arachnoid layer. Tissue plasminogen activator plays an important role as a key factor of defective coagulation. Historically, CSDH has often been treated via burr hole craniostomy using a closed drainage system. Several different operative strategies and peri-operative strategies such as the addition of burr holes, addition of cavity irrigation, position of drain, or postural position, have been described previously. Although the direction of the drainage tube, residual air, low intensity of T1-weighted images on MRI, and niveau formation have been reported as risk factors for recurrence, antiplatelet or anticoagulant drug use has not yet been verified as a risk factor. Recently, pharmaceutical strategies, including atorvastatin, significantly improved the neurological function in CSDH patients. Many case series, without randomization, have been reported; and given its promising result, several randomized clinical trials using pharmaceutical as well as operative and perioperative strategies were initiated to obtain sufficient data. In contrast, relatively fewer basic studies have achieved clinical applications in CSDH, although it is one of the most common clinical entities. Further scientific basic research may be essential for achieving a novel treatment strategy for CSDH.