Results of open thoracoabdominal aortic aneurysm repair

Nrf2 Signaling Pathway: Focus on Oxidative Stress in Spinal Cord Injury

Spinal cord injury (SCI) is a serious, disabling injury to the central nervous system that can lead to motor, sensory, and autonomic dysfunction below the injury plane. SCI can be divided into primary injury and secondary injury according to its pathophysiological process. Primary injury is irreversible in most cases, while secondary injury is a dynamic regulatory process. Secondary injury involves a series of pathological events, such as ischemia, oxidative stress, inflammatory events, apoptotic pathways, and motor dysfunction. Among them, oxidative stress is an important pathological event of secondary injury. Oxidative stress causes a series of destructive events such as lipid peroxidation, DNA damage, inflammation, and cell death, which further worsens the microenvironment of the injured site and leads to neurological dysfunction. The nuclear factor erythrocyte 2-associated factor 2 (Nrf2) is considered to be a key pathway of antioxidative stress and is closely related to the pathological process of SCI. Activation of this pathway can effectively inhibit the oxidative stress process and promote the recovery of nerve function after SCI. Therefore, the Nrf2 pathway may be a potential therapeutic target for SCI. This review deeply analyzed the generation of oxidative stress in SCI, the role and mechanism of Nrf2 as the main regulator of antioxidant stress in SCI, and the influence of cross-talk between Nrf2 and related pathways that may be involved in the pathological regulation of SCI on oxidative stress, and summarized the drugs and other treatment methods based on Nrf2 pathway regulation. The objective of this paper is to provide evidence for the role of Nrf2 activation in SCI and to highlight the important role of Nrf2 in alleviating SCI by elucidating the mechanism, so as to provide a theoretical basis for targeting Nrf2 pathway as a therapy for SCI.

Three-Staged Surgical Hybrid Treatment for an Extended Thoracoabdominal Aneurysm in a High-Risk Patient: A Case Report

Thoracoabdominal aortic aneurysm (TAAA) repair remains one of the most challenging procedures and is associated with high mortality and complication rates. Careful consideration of the surgical strategy is essential, particularly in cases involving extensive replacement and high-risk patients. A 61-year-old man with a 55-mm TAAA was referred for surgical treatment. Seven years earlier, he had undergone artificial vascular replacement for an infrarenal abdominal aortic aneurysm. His medical history included a myocardial infarction with a left ventricular ejection fraction (LVEF) of 20% and an apical thrombus. Additionally, he had chronic kidney disease, cerebral infarction, angina pectoris, hypertension, dyslipidemia, diabetes mellitus, and hyperuricemia. The preoperative plan involved a staged approach, beginning with total arch replacement (TAR) using the frozen elephant trunk (FET) technique and coronary artery bypass grafting (CABG), followed by thoracic endovascular aortic repair (TEVAR) and hybrid repair with abdominal debranching. The patient was discharged without complications. Although thoracoabdominal aortic surgery carries a high risk of mortality, it can be performed safely with careful preoperative assessment and the development of an individualized surgical strategy.

Differential impacts of clinical, anatomical, and procedural factors on early and late mortality following open thoracoabdominal aortic repair: a retrospective observational study

BACKGROUND

The operative outcomes of thoracoabdominal aortic aneurysms (TAAAs) are challenged by high operative mortality and disabling complications. This study aimed to explore the baseline clinical, anatomical, and procedural risk factors that impact early and late outcomes following open repair of TAAAs.

METHODS

We reviewed the medical records of 290 patients who underwent open repair of TAAAs between 1992 and 2020 at a tertiary referral center. Determinants of early mortality (within 30 days or in hospital) were analyzed using multivariable logistic regression models, while those of overall follow-up mortality were explored using multivariable Cox proportional hazards models and landmark analyses.

RESULTS

The rates of early mortality and spinal cord deficits were 13.1% and 11.0%, respectively, with Crawford extent II showing the highest rates. In the logistic regression models, older age (P < 0.001), high cardiopulmonary bypass (CPB) time (P < 0.001), and low surgical volume of the surgeon (P < 0.001) emerged as independent factors significantly associated with early mortality. During follow-up (median, 5.0 years; interquartile range, 1.1-7.6 years), 82 late deaths occurred (5.7%/patient-year). Cox proportional hazards models demonstrated that older age (P < 0.001) and low hemoglobin level (P = 0.032) were significant risk factors of overall mortality, while the landmark analyses revealed that the significant impacts of low surgical volume (P = 0.017), high CPB time (P = 0.002), and Crawford extent II (P = 0.017) on mortality only remained in the early postoperative period, without significant late impacts (all P > 0.05).

CONCLUSION

There were differential temporal impacts of perioperative risk variables on mortality in open repair of TAAAs, with older age and low hemoglobin level having significant impacts throughout the postoperative period, and low surgical volume, high CPB time, and Crawford extent II having impacts in the early postoperative phase.

Risk factors of 30-day and long-term mortality and outcomes in open repair of thoracoabdominal aortic aneurysm

BACKGROUND

Open repair of thoracoabdominal aortic aneurysm (TAAA) was characterized by significant risk of postoperative mortality and morbidity. The aim of this study was to determine the perioperative predictors of early and long-term mortality in patients undergoing open repair of TAAA. Besides, the postoperative outcomes in patients with open repair of TAAA were described.

METHODS

This is a single-center retrospective study, and 146 patients with open repair of TAAA from January 4, 2011, to November 22, 2018 was involved. Categorical variables were analyzed by the Chi-square test or Fisher's exact test, and continuous variables were analyzed by the independent sample t-test and the WilCoxon rank-sum test. Multivariate Logistic regression and Cox regression were applied to identify the predictors of 30-day and long-term mortality, respectively. The Kaplan Meier curves were used to illustrate survival with the Log-rank test.

RESULTS

The 30-day mortality was 9.59% (n = 14). Older than 50 years, the intraoperative volume of red blood cell (RBC) and epinephrine use were independently associated with postoperative 30-day mortality in open repair of TAAA. Long-term mortality was 17.12% (n = 25) (median of 3.5 years (IQR = 2-5 years) of follow-up). Prior open thoracoabdominal aortic aneurysm (TAAA) repair, aortic cross-clamping (ACC) time, intraoperative volume of RBC and use of epinephrine were independently correlated with long-term mortality.

CONCLUSIONS

Identifying perioperative risk factors of early and long-term mortaliy is crucial for surgeons. Intraoperative volume of RBC and use of epinephrine were predictors of both early and long-term mortality. In addition, patients of advanced age, prior open repair of TAAA and prolonged ACC time should be paid more attention.

Administration with curcumin alleviates spinal cord ischemia-reperfusion injury by regulating anti-oxidative stress and microglia activation-mediated neuroinflammation via Nrf2/NF-κB axis

Spinal cord ischemia-reperfusion injury (SCII) ranks as the common complication after aortic surgery, usually leading to devastating post-operative paraplegia. Microglia over-activation and neuronal cell loss are key pathological features of SCII. Curcumin is involved in several I/R injuries. However, its underlying mechanism in SCII remains elusive. Here, curcumin attenuated oxygen and glucose deprivation/reoxygenation (OGD/R)-induced oxidative injury in PC12 neuronal cells by increasing cell viability, inhibiting cell apoptosis, lactate dehydrogenase, malondialdehyde levels, but elevating anti-oxidative superoxide dismutase and glutathione peroxidase levels. Furthermore, curcumin restrained OGD/R-evoked microglia M1 activation by decreasing microglia M1 polarization marker IBA-1 and iNOS transcripts. Moreover, the increased inflammatory cytokine levels of TNF-α and IL-6 in microglia under OGD/R conditions were suppressed after curcumin treatment. Importantly, neuronal cells incubated with a conditioned medium from OGD/R-treated microglia exhibited lower cell viability and higher apoptotic ratio, which were overturned when microglia were treated with curcumin. Intriguingly, curcumin could inhibit the activation of the NF-κB pathway by Nrf2 enhancement in OGD/R-treated PC12 cells and microglia. Notably, targeting Nrf2 signaling reversed the protective efficacy of curcumin against OGD/R-evoked oxidative insult in neuronal, microglia M1 activation, inflammatory response, and microglial activation-evoked neuronal death. In vivo, curcumin improved histopathologic injury and neurologic motor function in SCII rats and attenuated oxidative stress, microglia activation and neuroinflammation in spinal cord tissues, and activation of the Nrf2/NF-κB pathway. Thus, curcumin may alleviate SCII by mitigating I/R-evoked oxidative injury in neuron and microglia activation-induced neuroinflammation and neuron death through Nrf2/NF-κB signaling, supporting a promising therapeutic agent for SCII.

Haemodynamic changes in visceral hybrid repairs of type III and type V thoracoabdominal aortic aneurysms

The visceral hybrid procedure combining retrograde visceral bypass grafting and completion endovascular stent grafting is a feasible alternative to conventional open surgical or wholly endovascular repairs of thoracoabdominal aneurysms (TAAA). However, the wide variability in visceral hybrid configurations means that a priori prediction of surgical outcome based on haemodynamic flow profiles such as velocity pattern and wall shear stress post repair remain challenging. We sought to appraise the clinical relevance of computational fluid dynamics (CFD) analyses in the setting of visceral hybrid TAAA repairs. Two patients, one with a type III and the other with a type V TAAA, underwent successful elective and emergency visceral hybrid repairs, respectively. Flow patterns and haemodynamic parameters were analysed using reconstructed pre- and post-operative CT scans. Both type III and type V TAAAs showed highly disturbed flow patterns with varying helicity values preoperatively within their respective aneurysms. Low time-averaged wall shear stress (TAWSS) and high endothelial cell action potential (ECAP) and relative residence time (RRT) associated with thrombogenic susceptibility was observed in the posterior aspect of both TAAAs preoperatively. Despite differing bypass configurations in the elective and emergency repairs, both treatment options appear to improve haemodynamic performance compared to preoperative study. However, we observed reduced TAWSS in the right iliac artery (portending a theoretical risk of future graft and possibly limb thrombosis), after the elective type III visceral hybrid repair, but not the emergency type V repair. We surmise that this difference may be attributed to the higher neo-bifurcation of the aortic stent graft in the type III as compared to the type V repair. Our results demonstrate that CFD can be used in complicated visceral hybrid repair to yield potentially actionable predictive insights with implications on surveillance and enhanced post-operative management, even in patients with complicated geometrical bypass configurations.

Debranching abdominal aortic hybrid surgery for aortic diseases involving the visceral arteries

Objective

Aortic diseases involving branches of the visceral arteries mainly include thoracoabdominal aortic aneurysm (TAAA), aortic dissection (AD) and abdominal aortic aneurysm (AAA). The focus of treatment is to reconstruct the splanchnic arteries and restore blood supply to the organs. Commonly used methods include thoracoabdominal aortic replacement, thoracic endovascular aortic repair and hybrid approaches. Hybrid surgery for aortic disease involving the visceral arteries, consisting of visceral aortic debranching with retrograde revascularization of the celiac trunk and renal arteries and using stent grafts, has been previously described and may be considered particularly appealing in high-risk patients. This study retrospectively analyzed recorded data of patients and contrasted the outcomes with those of a similar group of patients who underwent conventional open repair surgery.

Methods

Between 2019 and 2022, 72 patients (52 men) with an average age of 61.57 ± 8.66 years (range, 36-79 years) underwent one-stage debranching abdominal aortic hybrid surgery. These patients, the hybrid group, underwent preoperative Computed Tomographic Angiography (CTA) and had been diagnosed with aortic disease (aneurysm or dissection) involving the visceral arteries and were at high risk for open repair. The criteria used to define these patients as high-risk group who are in the need of hybrid treatment were American Society of Anesthesiologists (ASA) class 3 or 4. In all cases, we accomplished total visceral aortic debranching through a previous visceral artery retrograde revascularization with synthetic grafts (customized Y or four-bifurcated grafts), and aortic endovascular repair with one of two different commercially produced stent grafts (Medtronic® and Lifetech®). In some cases, we chose to connect the renal artery to the artificial vessel with a stent graft (Viabahn) and partly or totally anastomosed. We analyzed the results and compared the outcomes of the hybrid group with those of a similar group of 46 patients (36 men) with an average age 54.15 ± 12.12 years (range, 32-76). These 46 patients, the conventional open group, were selected for having had thoracoabdominal aortic replacement between 2019 and 2022.

Results

In the hybrid group, 72 visceral bypasses were completed, and endovascular repair was successful in all cases. No intraoperative deaths occurred. Perioperative mortality was 2.78%, and perioperative morbidity was 9.72% (renal insufficiency in 1, unilateral renal infarction in 5, Intestinal ischemia in 1). At 1-month postoperative CTA showed 2 endoleaks, one of which was intervened. At follow-up, there were unplanned reoperation rate of 4.29% and 5 (7.14%) deaths. The remaining patients' grafts were patent at postoperative CTA and no endoleak or stent graft migration had occurred. In the conventional open group, 1 died intraoperatively, 4 died perioperatively, perioperative mortality was 10.87% and complications were respiratory failure in 5, intestinal paralysis/necrosis in 4, renal insufficiency in 17, and paraplegia in 2. At follow-up, 5 (12.20%) patients presented with synthetic grafts hematoma 4 (9.76%) patient died, and 6 (14.63%) patients required unplanned reoperation intervention.

Conclusion

Hybrid surgery is technically feasible in selected cases. For aortic diseases involving the visceral arteries, the application of hybrid abdominal aorta debranching can simplify the operation process, decrease the risks of mortality and morbidity in high-risk and high-age populations and decrease the incidence of various complications while achieving ideal early clinical efficacy. However, a larger series is required for valid statistical comparisons, and longer follow-ups are necessary to evaluate the long-term efficacy of hybrid surgery.

Risk factors for target vessel endoleaks after physician-modified fenestrated or branched endovascular aortic arch repair: A retrospective study

Objective

Fenestrated or branched endovascular aortic arch repair (fb-arch repair) is an effective option for treating complex aortic arch lesions, including thoracic aortic aneurysms and aortic dissections. However, the relatively high rate of re-intervention due to target vessel (TV)-related endoleaks have raised concerns. This study aimed to determine risk factors for TV-related endoleaks after fb-arch repair.

Methods

This was a retrospective analysis of all patients undergoing fb-arch repair between 2017 and 2021in nanjing drum tower hospital of China. All the patients underwent computed tomography angiography (CTA) before surgery; at discharge; and at 3 months, 6 months, and yearly post-discharge. All procedures are performed with physician modified grafts. Two experienced vascular surgeons used CTA and vascular angiography data to assess endoleaks. The study endpoints were mortality, aneurysm rupture, and emergence of and re-intervention for TV-related endoleaks.

Results

During the follow-up period, 218 patients underwent fb-arch repair. There were seven perioperative deaths and four deaths during follow-up (two myocardial infarctions and two malignancies). There were nine additional patients who were excluded from the study (two strokes, three with abnormal aortic arch anatomy, and four with insufficient clinical data). Among the 198 patients considered (mean age, 59 ± 13.3 years; 85% male), 309 branch arteries were revascularized. A total of 35 TV-related endoleaks were identified in 28 patients during a mean follow-up of 23 ± 14 months (median 23, IQR 26.3): six type Ic, 4 type IIIb, and 20 type IIIc endoleaks. Patients in the endoleak group had greater aortic arch segment diameters (43.1 ± 5.1 vs. 40.3 ± 4.7; P = 0.004) and a greater number of TVs revascularized (2.0 ± 0.8 vs. 1.5 ± 0.8; P = 0.004) than those in the non-endoleak group. However, the morphological classification of the aortic arch did not seem to affect the occurrence of TV endoleaks (13%, 14%, and 15% for type І, II, and III aortic arches, respectively; P = 0.957). Pre-sewing branch stents in the fenestration position reduced the risk of TV endoleaks (5% vs. 14%; P = 0.037). Additionally, in TVs affected by aortic aneurysm or dissection, the risk of endoleaks increased after reconstruction (17% vs. 8%; P = 0.018). The incidence of secondary TV-related endoleaks after fb-arch repair was 14.1%.

Conclusion

The data from this study showed that the incidence of secondary target vessel related endoleaks after fb-arch repair is approximately 14.1%. Additionally, patients with a larger aortic arch diameter or more revascularized arteries during surgery were at increased risk TV-related endoleaks. The target vessels originating from the false lumen or aneurysm sac are more prone to endoleaks after reconstruction. Finally, prefabricated branch stents reduced risk of TV-related endoleaks.

TSG-6 released from adipose stem cells-derived small extracellular vesicle protects against spinal cord ischemia reperfusion injury by inhibiting endoplasmic reticulum stress

Background

Spinal cord ischemia reperfusion injury (SCIRI) is a complication of aortic aneurysm repair or spinal cord surgery that is associated with permanent neurological deficits. Mesenchymal stem cell (MSC)-derived small extracellular vesicles (sEVs) have been shown to be potential therapeutic options for improving motor functions after SCIRI. Due to their easy access and multi-directional differentiation potential, adipose‐derived stem cells (ADSCs) are preferable for this application. However, the effects of ADSC-derived sEVs (ADSC-sEVs) on SCIRI have not been reported.

Results

We found that ADSC-sEVs inhibited SCIRI-induced neuronal apoptosis, degradation of tight junction proteins and suppressed endoplasmic reticulum (ER) stress. However, in the presence of the ER stress inducer, tunicamycin, its anti-apoptotic and blood–spinal cord barrier (BSCB) protective effects were significantly reversed. We found that ADSC-sEVs contain tumor necrosis factor (TNF)-stimulated gene-6 (TSG-6) whose overexpression inhibited ER stress in vivo by modulating the PI3K/AKT pathway.

Conclusions

ADSC-sEVs inhibit neuronal apoptosis and BSCB disruption in SCIRI by transmitting TSG-6, which suppresses ER stress by modulating the PI3K/AKT pathway.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02963-4.

Fenestrated and Branched Stent-Grafts for the Treatment of Thoracoabdominal Aortic Aneurysms: A Systematic Review and Meta-Analysis

Purpose

To investigate the safety and efficacy of total endovascular repair for thoracoabdominal aortic aneurysms (TAAAs) with fenestrated and branched stent-grafts.

Methods

The MEDLINE, EMBASE, and Cochrane databases were searched between January 2001 and December 2021 to identify literature relevant to the use of fenestrated and branched endografts for the treatment of TAAAs. Studies with <4 cases and those on juxtarenal or pararenal aortic aneurysms were excluded. Meta-analyses were conducted to evaluate spinal cord ischemia (SCI), irreversible SCI, renal insufficiency, dialysis, endoleak, reintervention, target vessel patency, 30-day mortality and overall mortality. Fourteen studies comprising 1,114 patients (mean age 72.42 years, 847 men) were selected. The mean TAAA diameter was 67 mm. The Crawford TAAA classification was type I-III in 759 cases, type IV in 344 cases, and type V in 10 cases. Outcomes of the meta-analysis are reported as proportions and 95% confidence intervals (CIs).

Results

The pooled rates for 30-day mortality and overall mortality were 6% and 18%, respectively. The pooled rate for technical success was 94% (95% CI, 93–96%), for SCI was 8% (95% CI, 7–10%), for irreversible SCI was 6% (95% CI, 4–7%), for reversible SCI was 5% (95% CI, 4–6%), for reversible SCI was 2% (95% CI, 2–3%), for renal insufficiency was 7% (95% CI, 5–10%), for dialysis was 3% (95% CI, 2–4%), for target vessel patency was 98% (95% CI, 97–99%), and for reintervention was 15% (95% CI, 9–24%).

Conclusion

Fenestrated and branched endografts for the treatment of TAAAs are safe and effective with acceptable early results. Lifelong regular follow-up and additional prospective studies are necessary to substantiate whether this technique is valid.

Neuronal Pre- and Postconditioning via Toll-like Receptor 3 Agonist or Extracorporeal Shock Wave Therapy as New Treatment Strategies for Spinal Cord Ischemia: An In Vitro Study

Spinal cord ischemia (SCI) is a devastating and unpredictable complication of thoracoabdominal aortic repair. Postischemic Toll-like receptor 3 (TLR3) activation through either direct agonists or shock wave therapy (SWT) has been previously shown to ameliorate damage in SCI models. Whether the same applies for pre- or postconditioning remains unclear. In a model of cultured SHSY-5Y cells, preconditioning with either poly(I:C), a TLR3 agonist, or SWT was performed before induction of hypoxia, whereas postconditioning treatment was performed after termination of hypoxia. We measured cytokine expression via RT-PCR and utilized Western blot analysis for the analysis of signaling and apoptosis. TLR3 activation via poly(I:C) significantly reduced apoptotic markers in both pre- and postconditioning, the former yielding more favorable results through an additional suppression of TLR4 and its downstream signaling. On the contrary, SWT showed slightly more favorable effects in the setting of postconditioning with significantly reduced markers of apoptosis. Pre- and post-ischemic direct TLR3 activation as well as post-ischemic SWT can decrease apoptosis and proinflammatory cytokine expression significantly in vitro and might therefore pose possible new treatment strategies for ischemic spinal cord injury.

Endovascular repair for thoracoabdominal aortic aneurysms: current status and future challenges

Open surgical repair has been the gold standard for treatment of thoracoabdominal aortic aneurysms (TAAA). Currently, open surgical repair has been reserved mostly for young and fit patients with connective tissue disorders, using separate branch vessel reconstructions instead of 'island' patches, and distal perfusion instead of a 'clamp and go' technique. Endovascular repair has gained widespread acceptance because of its potential to significantly decrease morbidity and mortality. Several large aortic centers have developed dedicated clinical programs to advance techniques of fenestrated-branched endovascular aortic repair (FB-EVAR) using patient-specific and off-the-shelf devices, which offers a less-invasive alternative to open repair. Although FB-EVAR was initially considered an option for older and frail patients, many centers have expanded its indications to any patient with suitable anatomy and no evidence of connective tissue disorders, independent of their clinical risk. In this article, we review current techniques and outcomes of endovascular TAAA repair.

MiR-128-3p Alleviates Spinal Cord Ischemia/Reperfusion Injury Associated Neuroinflammation and Cellular Apoptosis via SP1 Suppression in Rat

BACKGROUND

Neuroinflammation and cellular apoptosis caused by spinal cord ischemia/reperfusion (I/R) injury result in neurological dysfunction. MicroRNAs (miRs) have crucial functions in spinal cord I/R injury pathogenesis according to previous evidences. Herein, whether miR-128-3p contributes to spinal cord I/R injury by regulating specificity protein 1 (SP1) was assessed.

METHODS

A rat model of spinal cord I/R injury was established by occluding the aortic arch for 14 min. Then, miR-128-3p's interaction with SP1 was detected by dual-luciferase reporter assays. Next, miR-128-3p mimic and inhibitor, as well as adenovirus-delivered shRNA specific for SP1 were injected intrathecally for assessing the effects of miR-128-3p and SP1 on rats with spinal cord I/R injury. SP1, Bax and Bcl-2 expression levels in I/R injured spinal cord tissues were evaluated by Western blotting, while IL-1β, TNF-α, and IL-6 were quantitated by ELISA. Tarlov scores were obtained to detect hind-limb motor function. Evans blue (EB) dye extravasation was utilized to examine blood-spinal cord barrier (BSCB) permeability. Terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) staining was performed for neuronal apoptosis assessment.

RESULTS

MiR-128-3p expression was decreased, while SP1 amounts were increased in rat spinal cord tissue specimens following I/R. SP1 was identified as a miR-128-3p target and downregulated by miR-128-3p. MiR-128-3p overexpression or SP1 silencing alleviated I/R-induced neuroinflammation and cell apoptosis, and improved Tarlov scores, whereas pretreatment with miR-128-3p inhibitor aggravated the above injuries.

CONCLUSION

Overexpression of miR-128-3p protects neurons from neuroinflammation and apoptosis during spinal cord I/R injury partially by downregulating SP1.

Effect of heated humidified ventilation on intraoperative core temperature and prognosis in normothermic thoraco-abdominal aortic aneurysm repair

Background

To evaluate whether the heated humidified ventilation can effectively maintain core temperature and improve prognosis in normothermic thoraco-abdominal aortic aneurysm repair surgery.

Methods

Patients who were scheduled for normothermic thoraco-abdominal aortic aneurysm repair surgery were randomized into the group using heated humidified ventilation combined with water blanket and the group using water blanket only. During the operation, the core temperature will be measured every 30 minutes. We analyzed intraoperative core-temperature, coagulation function and in-hospital mortality.

Results

HHV&WB group showed lesser decrease in core temperature than WB groups in the first two hours, while WB group had a higher body temperature at the third to fifth hour (2-hour: 35.45±0.47 vs. 35.24±0.59 °C, P=0.284; 5-hour: 35.38±0.70 vs. 35.51±0.88 °C, P=0.664). There was less blood loss, dosage of coagulation drugs and in-hospital mortality (13.33% vs. 20.00%, P=1) in the HHV&WB group.

Conclusions

Heated humidified ventilation can improve the prognosis of normothermic thoraco-abdominal aortic aneurysm repair surgery to some extent, but it can only maintain the core temperature during the first 2 hours.

Activation of SK/KCa Channel Attenuates Spinal Cord Ischemia-Reperfusion Injury via Anti-oxidative Activity and Inhibition of Mitochondrial Dysfunction in Rabbits

Spinal cord ischemia-reperfusion injury (SCI/R) is a rare but devastating disorder with a poor prognosis. Small conductance calcium-activated K⁺ (SK/K_Ca) channels are a family of voltage-independent potassium channels that are shown to participate in the pathological process of several neurological disorders. The aim of this study was to investigate the role of SK/K_Ca channels in experimental SCI/R in rabbits. The expression of SK/K_Ca1 protein significantly decreased in both cytoplasm and mitochondria in spinal cord tissues after SCI/R. Treatment with 2 mg/kg NS309, a pharmacological activator for SK/K_Ca channel, attenuated SCI/R-induced neuronal loss, spinal cord edema and neurological dysfunction. These effects were still observed when the administration was delayed by 6 h after SCI/R initiation. NS309 decreased the levels of oxidative products and promoted activities of antioxidant enzymes in both serum and spinal cord tissues. The results of ELISA assay showed that NS309 markedly decreased levels of pro-inflammatory cytokines while increased anti-inflammatory cytokines levels after SCI/R. In addition, treatment with NS309 was shown to preserve mitochondrial respiratory complexes activities and enhance mitochondrial biogenesis. The results of western blot analysis showed that NS309 differentially regulated the expression of mitochondrial dynamic proteins. In summary, our results demonstrated that the SK/K_Ca channel activator NS309 protects against SCI/R via anti-oxidative activity and inhibition of mitochondrial dysfunction, indicating a therapeutic potential of NS309 for SCI/R.

Endovascular Treatment of Various Aortic Pathologies: Review of the Latest Data and Technologies

The technologies and innovations applicable to endovascular treatment for complex aortic pathologies have progressed rapidly over the last two decades. Although the initial outcomes of an endovascular aortic repair have been excellent, as long-term data became available, complications including endoleaks, endograft migration, and endograft infection have become apparent and are of concern. Previously, the indication for endovascular therapy was restricted to descending thoracic aortic aneurysms and abdominal aortic aneurysms. However, its indication has expanded along with the improvement of techniques and devices, and currently, it has become possible to treat pararenal aortic aneurysms and Crawford type 4 thoracoabdominal aortic aneurysm (TAAA) using the off-the-shelf devices. Additionally, custom-made devices allow for the treatment of arch or more extensive TAAAs. Endovascular treatment is applied not only to aneurysms but also to acute/chronic dissections. However, long-term outcomes are still unclear. This article provides an overview of available devices and the results of endovascular treatment for various aortic pathologies.

Thoracoabdominal aortic replacement in patients aged 50 and younger

OBJECTIVE

Open repair of a thoracoabdominal aortic aneurysm (TAAA) has been regarded as one of the most invasive procedures in cardiovascular surgery. Conversely, endovascular technology currently enables the repair of the thoracoabdominal aorta, and this approach is less invasive. However, the long-term durability of this method of endovascular repair remains unknown. This investigation retrospectively analyzed the long-term durability of thoracoabdominal aorta repair in patients aged 50 and younger.

PATIENTS AND METHODS

Since 1995, 100 patients aged 50 and younger underwent thoracoabdominal aortic replacement at our institution. There were 63 males, and the average age was 38 ± 7. Ninety-six had aortic dissection as an aortic pathology. Marfan syndrome was found in 61 patients, Loeys-Dietz in 10, Acta 2 mutations in 4, aortitis in 2, and Ehlers-Danlos syndrome in 1. There were 2 patients with a type I TAAA, 56 with a type II, 33 with a type III, and 9 with a type IV.

RESULTS

There were 3 hospital deaths (3%), of which 2 were emergent cases. Spinal cord injury occurred in 1 patient (1%). Two patients (2%) had wound complications. Three patients suffered cerebral hemorrhage and 1 had an intramedullary infection, of which all were associated with cerebrospinal fluid drainage. The 3-year survival rate after the operation was 94%, that of 5 years was 94%, and that of 10 years was 91%.

CONCLUSIONS

Results of thoracoabdominal aortic replacement in patients aged 50 and younger were favorable. While spinal cord complications were rare, cerebrospinal drainage revealed several complications in this series. Evolving endovascular repair needs to be compared with these results, especially in patients aged 50 and younger.

Methane Medicine: A Rising Star Gas with Powerful Anti-Inflammation, Antioxidant, and Antiapoptosis Properties

Methane, the simplest organic compound, was deemed to have little physiological action for decades. However, recently, many basic studies have discovered that methane has several important biological effects that can protect cells and organs from inflammation, oxidant, and apoptosis. Heretofore, there are two delivery methods that have been applied to researches and have been proved to be feasible, including the inhalation of methane gas and injection with the methane-rich saline. This review studies on the clinical development of methane and discusses about the mechanism behind these protective effects. As a new field in gas medicine, this study also comes up with some problems and prospects on methane and further studies.

State-of the-art review on the renal and visceral protection during open thoracoabdominal aortic aneurysm repair

During open thoracoabdominal aortic aneurysm repair (OTAAAR), there is an inevitable organ ischemic period that occurs when the abdominal arteries are being reattached to the aortic graft. Despite various protective techniques, the incidence of renal and visceral complications remains substantial. This state-of-the-art review gives an overview of the current and most evidence-based organ protection methods during OTAAAR, based on the most recent publications and personal experience. An electronic search was performed in four medical databases, using the following MeSH terms: thoracoabdominal aneurysm, TAAAR, visceral protection, renal protection, kidney, perfusion, and intestines. Every publication type was considered. The literature search was ended on August 31st, 2017. The left heart bypass (LHB) is currently the most frequent adjunct to provide distal aortic perfusion (DAP) during aortic clamping. Together with systemic hypothermia, it forms the cornerstone in organ protection during aortic clamping. Further renal protection can be obtained by selective renal perfusion (SRP) with cold blood or cold crystalloid solution, the latter enriched with mannitol. The perfusion should be administered in a volume- and pressure-controlled way and, if possible, by use of a pulsatile pump. Selective visceral perfusion (SVP) is not routinely used, as it does not provide adequate blood flow for visceral protection. The best way to protect the intestines is by minimizing the ischemic time. The preservation of renal and visceral function after OTAAAR can only be obtained with specific strategies before, during, and after the operation. This involves a series of measures, including selective digestive decontamination (SDD), avoidance of nephrotoxic drugs, minimizing the renal and intestinal ischemic time, systemic cooling, avoidance of hemodynamic instability, and regional protective perfusion of the kidneys. Future innovations in catheters, cardiac bypass flow types, mechanical components, hybrid vascular grafts, and pharmaceutical protection measures will hopefully further reduce organ complications.

Thoracoabdominal aortic aneurysm repair: open, endovascular, or hybrid?

Successful repair of complex thoracoabdominal aortic aneurysms requires careful surgical planning based on anatomic and patient considerations. Not only are surgical considerations key, but also post-operative care, regardless of surgical approach, can dramatically impact both short- and long-term outcomes. While open repair has been the gold standard for decades, the technical challenges associated with operative repair, a specialty approach requisite for good outcomes, and the unique challenges in the post-operative care of these patients have given providers pause when considering operative intervention. The relatively recent development of elegant endovascular and hybrid approaches to this problem has shown improved short-term morbidity and reasonable durability. Here, we discuss these three techniques for correction of complex thoracoabdominal aortic aneurysms to provide some guidance for optimization of outcomes based on individual patient anatomy and comorbid conditions.

The β-d-Endoglucuronidase Heparanase Is a Danger Molecule That Drives Systemic Inflammation and Correlates with Clinical Course after Open and Endovascular Thoracoabdominal Aortic Aneurysm Repair: Lessons Learnt from Mice and Men

Thoracoabdominal aortic aneurysm (TAAA) is a highly lethal disorder requiring open or endovascular TAAA repair, both of which are rare, but extensive and complex surgical procedures associated with a significant systemic inflammatory response and high post-operative morbidity and mortality. Heparanase is a β-d-endoglucuronidase that remodels the endothelial glycocalyx by degrading heparan sulfate in many diseases/conditions associated with systemic inflammation including sepsis, trauma, and major surgery. We hypothesized that (a) perioperative serum levels of heparanase and heparan sulfate are associated with the clinical course after open or endovascular TAAA repair and (b) induce a systemic inflammatory response and renal injury/dysfunction in mice. Using a reverse-translational approach, we assessed (a) the serum levels of heparanase, heparan sulfate, and the heparan sulfate proteoglycan syndecan-1 preoperatively as well as 6 and 72 h after intensive care unit (ICU) admission in patients undergoing open or endovascular TAAA repair and (b) laboratory and clinical parameters and 90-day survival, and (c) the systemic inflammatory response and renal injury/dysfunction induced by heparanase and heparan sulfate in mice. When compared to preoperative values, the serum levels of heparanase, heparan sulfate, and syndecan-1 significantly transiently increased within 6 h of ICU admission and returned to normal within 72 h after ICU admission. The kinetics of any observed changes in heparanase, heparan sulfate, or syndecan-1 levels, however, did not differ between open and endovascular TAAA-repair. Postoperative heparanase levels positively correlated with noradrenalin dose at 12 h after ICU admission and showed a high predictive value of vasopressor requirements within the first 24 h. Postoperative heparan sulfate showed a strong positive correlation with interleukin-6 levels day 0, 1, and 2 post-ICU admission and a strong negative correlation with lactate clearance during the first 6 h post-ICU admission. Moreover, systemic administration of heparanase and heparan sulfate induced an inflammatory response and a small degree of renal dysfunction in mice. In conclusion, these results suggest that heparanase and heparan sulfate exhibit a substantial role as clinically relevant danger molecules and may serve as both, promising biomarkers and therapeutic targets in patients undergoing open or endovascular TAAA repair and, indeed, other conditions associated with significant systemic inflammation.

Improved outcomes and value in staged hybrid extent II thoracoabdominal aortic aneurysm repair

OBJECTIVE

Complex Crawford extent II thoracoabdominal aortic aneurysms (TAAAs) can be treated in a hybrid manner with proximal thoracic endovascular aneurysm repair, followed by staged distal open thoracoabdominal repair. This study evaluated the outcomes and health care-associated value of this new method compared with traditional open repair over 10 years.

METHODS

A prospectively collected database was used to identify all patients with an extent II TAAA undergoing repair at a single institution between 2005 and 2015. Patient characteristics, postoperative outcomes, and incidence of major adverse events (MAEs; renal failure, spinal cord ischemia, death) were compared. After adjusting for time since surgery, value was analyzed looking at quality (1/MAE) divided by cost (total health system cost). This was multiplied by a constant to set the value of open TAAA repair to 100.

RESULTS

A total of 113 consecutive patients underwent extent II TAAA repairs, of whom 25 (22.1%) had a staged hybrid approach with a median of 129 days between procedures. No baseline differences in demographic or comorbidity variables existed between groups (P > .05). The hybrid group had shorter operative time (255 vs 306 minutes; P = .01), shorter postoperative length of stay (10.1 vs 13.3 days; P = .02), and reduced blood loss (1300 vs 2600 mL; P = .01) at the time of open operation. Despite higher rates of acute kidney injury in the hybrid group (76.0% vs 51.1%; P = .03), there was no difference in renal failure (8.0% vs 4.5%; P = .84). The incidence of MAEs was lower in the staged hybrid group (20.0% vs 48.9%; P = .01), without a difference in hospital mortality (4.0% vs 3.4%; P = .89). Median total cost was higher in the hybrid group ($112,920 vs $72,037; P = .003). Value was improved in the hybrid group by 56% using mean cost and 178% by median cost.

CONCLUSIONS

The 20% MAE rate associated with staged hybrid repair of extent II TAAA was significantly decreased compared with open repair, with a relative reduction of >50%. Despite higher total hospital costs, staged hybrid repair had 56% to 178% higher health care-related value compared with standard open repair. In an era of increasing focus on costs and quality, staged hybrid repair of extensive TAAAs is associated with fewer complications than open TAAA repair, resulting in a good value investment from a resource utilization perspective.

Perioperative cerebrospinal fluid drainage for the prevention of spinal ischemia after endovascular aortic repair

Endovascular treatment of thoracic and thoracoabdominal aortic diseases is accompanied by a risk of spinal ischemia in 1-19% of patients, depending on the entity and extent of the disease. The use of perioperative drainage of cerebrospinal fluid is one of the invasive measures to reduce the occurrence of this severe complication. This article reviews the incidence of spinal ischemia, its risk factors, the evidence for carrying out cerebrospinal fluid drainage and its modern use by means of an automated, pressure controlled system (LiquoGuard®7).

Thoracoabdominal aortic replacement for Crawford extent II aneurysm after thoracic endovascular aortic repair

BACKGROUND

The surgical treatment of Crawford extent II aneurysms after thoracic endovascular aortic repair (TEVAR) remains challenging, because of the need to remove the failed endograft and the complexity of the aortic reconstruction. We retrospectively reviewed our experience with surgical management of Crawford extent II aneurysms after TEVAR using thoracoabdominal aortic replacement (TAAR).

METHODS

Eleven patients (10 males, 1 female) with Crawford extent II aneurysm after TEVAR were treated with TAAR between August 2012 and May 2015. The indications included: diameter >5.0 cm; persistent pain; size increase >0.5 cm/year; and no suitable landing zone for re-TEVAR. Five patients underwent surgery under deep hypothermic cardiac arrest, two under mild hypothermic cardiopulmonary bypass, and four under direct aortic cross-clamping under normothermia. Two patients had Marfan syndrome.

RESULTS

There were no in-hospital deaths. Continuous renal replacement therapy was required in three patients. One patient needed re-intubation, and two patients had prolonged intubation (>72 h). One patient sustained paraplegia after surgery but recovered during follow-up. Cerebrospinal fluid drainage were used in four patients (3 immediately in the operation room, and 1 in the intensive care unit when the patient suffered paraplegia). One patient died during follow-up.

CONCLUSIONS

TAAR represents a feasible option for the treatment of Crawford extent II aneurysms after TEVAR, with acceptable surgical risks and favorable results.

Propofol protects against blood-spinal cord barrier disruption induced by ischemia/reperfusion injury

Propofol has been shown to exert neuroprotective effects on the injured spinal cord. However, the effect of propofol on the blood-spinal cord barrier (BSCB) after ischemia/reperfusion injury (IRI) is poorly understood. Therefore, we investigated whether propofol could maintain the integrity of the BSCB. Spinal cord IRI (SCIRI) was induced in rabbits by infrarenal aortic occlusion for 30 minutes. Propofol, 30 mg/kg, was intravenously infused 10 minutes before aortic clamping as well as at the onset of reperfusion. Then, 48 hours later, we performed histological and mRNA/protein analyses of the spinal cord. Propofol decreased histological damage to the spinal cord, attenuated the reduction in BSCB permeability, downregulated the mRNA and protein expression levels of matrix metalloprotease-9 (MMP-9) and nuclear factor-κB (NF-κB), and upregulated the protein expression levels of occludin and claudin-5. Our findings suggest that propofol helps maintain BSCB integrity after SCIRI by reducing MMP-9 expression, by inhibiting the NF-κB signaling pathway, and by maintaining expression of tight junction proteins.

Thoracoabdominal aortic aneurysm (extent II) repair in a patient with systemic vasculitis

Conventional open repair is a gold standard for treating thoracoabdominal aortic aneurysm (TAAA) in patients with connective tissue disorders or systemic vasculitis. In a 42-year-old male patient with systemic vasculitis, TAAA extent II open repair was performed at our hospital. Here, we present the case with a video clip and technical tips.

[Endovascular versus conventional vascular surgery - old-fashioned thinking? Part 1: interventions on the aorta]

Endovascular therapy has widely replaced conventional open vascular surgical reconstruction. For this reason both techniques were widely considered to be competing approaches. Evidence-based data from randomized prospective trials, meta-analyses and clinical registries, however, demonstrated that both techniques should be used to complement each other. It became increasingly more evident that the use of either procedure depends on the underlying disease and the anatomical conditions, whereby a combination of both (hybrid approach) may be the preferred option in certain situations. This review focuses on the treatment of complicated acute type B aortic dissection, descending thoracic aortic aneurysms, thoracoabdominal aortic aneurysms as well as asymptomatic and ruptured abdominal aortic aneurysms.

Hybrid Thoracic Endovascular Aortic Repair for Intercostal Patch Aneurysm after Thoracoabdominal Aortic Replacement

We report a case of hybrid thoracic endovascular aortic repair for intercostal patch aneurysm after thoracoabdominal aortic replacement. Eighteen years ago, a 63-year-old woman with Marfan syndrome had undergone thoracoabdominal aortic replacement with reimplantation of the intercostal artery in an island fashion. Follow-up computed tomography (CT) revealed a remaining intercostal patch aneurysm of diameter 60 mm 17 years after the last operation. Hybrid thoracic endovascular aortic repair for exclusion of this intercostal patch aneurysm was successfully performed, with visceral artery bypasses. Postoperative CT showed no anastomotic stenosis or endoleak.

Expression of C5a and its receptor following spinal cord ischemia reperfusion injury in the rat

STUDY DESIGN

Experimental study.

OBJECTIVE

To investigate the expression of C5a and its receptor after spinal cord ischemia reperfusion injury (SIRI) in rat.

SETTING

Department of Neurosurgery, the Second Affiliated Hospital, Xi'an Jiaotong University, Shaanxi Province, Xi'an, China

METHODS

Sprague Dawley rats were subjected to 1 h of infrarenal aorta occlusion to induce spinal cord ischemia. Spinal cord was reperfused for 12, 24, 48 h or 3 days separately after ischemia, respectively. Enzyme-linked immunosorbent assay was used to detect C5a in rat serum. Immunofluorescent staining was performed to detect the expression and cellular localization of C5aR in spinal cord following SIRI.

RESULTS

Following SIRI, the motor behavior of the rats was significantly compromised. The serum concentration of C5a in the rat was elevated after SIRI and peaked at 24 h. C5aR was significantly upregulated in the lumbar spinal cord following SIRI and expressed on motor neurons and the microglia, but not astrocyte. There was no significant difference in the expression level of C5aR localized on motor neurons after SIRI. Remarkable upregulation of the C5aR may be associated with increased number of C5aR-positive microglia and elevated cellular expression level.

CONCLUSION

This study provides the first evidence of the expression of C5a and its receptors in SIRI and suggests their possible contribution to SIRI in a rat model.

Visceral Debranching for the Treatment of Thoracoabdominal Aortic Aneurysms: Based on a Presentation at the 2013 VEITH Symposium, November 19-23, 2013 (New York, NY, USA)

Surgical repair of thoracoabdominal aortic aneurysms (TAAA) is associated with significant morbidity and mortality. Hybrid approaches that involve visceral debranching and aortic endografting allow for an alternative approach in certain high-risk patients. In most circumstances the visceral vessels can be bypassed in a retrograde manner from the iliac arteries via a midline laparotomy, and the aortic aneurysm subsequently excluded with standard aortic endografts. These procedures avoid the extensive two-cavity exposure, aortic cross-clamping, and mechanical circulatory support that comprise open TAAA repair, and offer the theoretical advantage of being less invasive. Despite this, outcomes have been mixed with reported perioperative mortality rates of 0% and 34% and permanent paraplegia rates of 0% to 13% in most major series. The reported outcomes, as well as the variation between centers, highlight the importance of patient selection in undertaking hybrid repair. In practice, the best outcomes are achieved in patients who have high-risk anatomy, rather than high-risk comorbidities.

Contemporary outcomes of open repair of thoracoabdominal aortic aneurysm in young patients

Background

Endovascular technology now permits total endovascular thoracoabdominal aortic aneurysm (TAAA) repair with high volume centres reporting encouraging results. The long-term durability of such stent grafts is unknown, leading to concerns regarding their use in younger patients. This study reports contemporary outcomes of open repair in young patients.

Methods

Outcomes for patients age 60 or younger undergoing open TAAA repair between June 1999 and August 2013 with prospective collected data were analysed retrospectively.

Results

Thirty-seven patients (31 men, 84%) with a median age of 56 (range 22–60) were identified with a median TAAA diameter of 6.9 cm (range 5.6-11). Aneurysm aetiology included degenerative change (18), dilation of chronic dissection (10), connective tissue disease (7) and mycotic degeneration (2). Crawford Type IV TAAA were most commonly treated (17), followed by Type II (10), Type III (7) and Type I (3). Two (5%) patients died in hospital, one from multiple organ failure and one from respiratory failure. Three patients (8%) developed temporary paraplegia, all of whom made a complete recovery and 4 (11%) patients required temporary renal replacement therapy. Median critical care stay was 5 days (range 2–28) with an in-hospital stay of 14 days (range 7–83). During a median follow-up of 72 months (range 13–171), no patient subsequently required any further aneurysm related surgical or radiological intervention. The mean (SEM) survival time was 138.5 (11) months. The 5 year survival was 79.7% (8.3) including early deaths, with no aneurysm related complications.

Conclusions

The outcome of open TAAA repair in patients aged less than 60 years is favorable. It is against these results that evolving endovascular interventions must be compared.

Electronic supplementary material

The online version of this article (doi:10.1186/s13019-014-0195-4) contains supplementary material, which is available to authorized users.

Long-term outcomes in thoracoabdominal aortic aneurysm repair for chronic type B dissection

INTRODUCTION

Open repair for chronic aortic dissection remains a challenging surgical option. Different centers report diverse experiences and outcomes pertaining to thoracoabdominal aortic aneurysm repair (TAAAR) for chronic type B dissection. We highlight our center's experience and results on a background of published literature and current evidence.

METHODS

We reviewed 214 open TAAAR performed between October 1998 and February 2014. Of these, chronic type B dissection was present in 62 (29.0%) patients. We reviewed these patients in terms of demographics, operative characteristics and outcomes. Thirteen (21.0%) patients had surgery on the descending thoracic aorta [Category A =2 (3.2%), B =0 (0%), C =11 (17.7%)] and 49 (79.0%) in the thoracoabdominal thoracic aorta [Crawford extent I =5 (8.1%), extent II =39 (62.9%), extent III =4 (6.5%), extent IV =1 (1.6%)]. Left heart bypass was used in 12 (19.4%) patients.

RESULTS

The composite in-hospital endpoint, adverse outcome-defined as operative death, renal failure necessitating dialysis at discharge, stroke, or permanent paraplegia or paraparesis-occurred after 28 (45.2%) procedures. There were 14 (22.6%) operative deaths. In-hospital mortality was seven (16.3%) out of 43 elective patients, and increased to seven (36.8%) of the 19 non-elective ones. Permanent paraplegia or paraparesis occurred after two (3.2%) cases, stroke occurred after seven (11.3%) and renal failure requiring dialysis occurred after 16 (25.8%). Mean follow-up time was 3.2 years and actuarial 5-year mortality was 27.4% [nine (14.5%) elective and eight (12.9%) non-elective patients].

CONCLUSIONS

TAAAR in chronic type B dissection carries a substantial risk of early adverse outcomes. The results could be well alleviated with cases directed towards specialized regional and supra-regional centers. Although the endovascular approaches offer relatively low mortality and morbidity, there is a lack of long-term data and guidelines on their use. There is a need for a multidisciplinary international registry on the management of thoracoabdominal aortic aneurysms and dissection. This would provide a degree of guidance on relevant clinical and surgical judgments and outcomes.

Intrathecal antagonism of microglial TLR4 reduces inflammatory damage to blood-spinal cord barrier following ischemia/reperfusion injury in rats

BACKGROUND

Inflammatory reaction in blood-spinal cord barrier (BSCB) plays a crucial role in ischemia/reperfusion (I/R) injury. It has been shown that microglia could be activated through Toll-like receptors (TLRs). Therefore, we hypothesize that TLR4 is involved in the microglial activation and BSCB disruption after I/R.

RESULTS

To verify our hypothesis, we analyzed the behavioral data, changes of BSCB permeability, as well as expressions of microglial marker Iba-1 and TLR4 in spinal cord I/R model induced by 14 min aortic occlusion. Double immunostaining reveals that after I/R, Iba-1 immunoreactivity increased gradually 12 h after reperfusion and maintained at a such level throughout 36 h. Such increasing pattern of Iba-1 expression is consistent with the increases in Evan's Blue (EB) extravasation, spinal water content and mechanical allodynia demonstrated by lowed withdrawal threshold to Von Frey filaments. Moreover, double immunostaining suggested that TLR4 was highly expressed in microglia. Intrathecal infusion of minocycline and TAK-242 (TLR4 inhibitor) treatment attenuated I/R-induced allodynia and BSCB leakage. In contrast, LPS induced TLR4 expression aggregated above-mentioned injuries. Furthermore, the nuclear factor-kappa B (NF-κB) activity has a similar profile as TLR4 activity. It is consisted with the results of NF-κB mRNA and protein expression changes and activation of downstream cytokine, IL-1β. Expectedly, intrathecal infusion of pyrrolidine dithiocarbamate (PDTC), a NF-κB inhibitor, showed similar protective effects as minocycline and TAK-242. In addition, our data show that TLR4 closely involved in I/R-induced inflammatory damage induced neuronal apoptosis. Significantly, neutralizing TLR4 function largely reduced neuronal apoptosis determined by NeuN immunoreactivity in ventral gray matter and increased percentage of double-label cells with cleaved caspase3, whereas LPS reversed these effects. Similarly, inhibitions of microglia and NF-κB with minocycline or PDTC treatment accordingly perform the same protective effects on I/R injury.

CONCLUSION

The results indicate that compromised BSCB caused by I/R injury lead to spinal microglial activation and TLR4, its membrane-bound receptor, up-regulation, which then initiate neuro-inflammation and neuro-apoptosis via NF-κB/ IL-1β pathway. To inhibit the positive feedback loop of TLR4-microglia-NF-κB/ IL-1β pathway by minocycline, TAK-242 (TLR4 inhibitor) and pyrrolidine dithiocarbamate (PDTC, NF-κB inhibitor) may provide new targets for treating I/R injury in clinic.