Effect of Repetitive Transcranial Magnetic Stimulation on Post-stroke Dysphagia in Acute Stage.

Repetitive transcranial magnetic stimulation (rTMS) play a important role for rehabilitation in stroke. But therapeutic schedule of rTMS in dysphagia after acute stroke is still controversial. The purpose of this study was to investigate the therapeutic effect of rTMS with different frequencies on dysphagia after acute stroke. From August 2019 to December 2020, 45 patients with post-stroke dysphagia were selected as research subjects, and randomly divided into 3 groups: the high frequency stimulation on bilateral hemisphere group (High group), bilateral high frequency stimulation on the affected hemisphere and low frequency stimulation on the unaffected hemisphere group (High-low group), and sham stimulation group (Sham group). On the basis of routine swallowing training (30 min) for all patients, the high group received 5 Hz rTMS in both hemispheres, the high- low group received 5 Hz rTMS in the unaffected hemisphere, 1 Hz rTMS in the affected hemisphere, and the sham stimulation group received sham stimulation in bilateral hemisphere. All participants were assessed with dysphagia handicap index (DHI), functional oral intake scale (FOIS) and videofluoroscopic swallowing study (VFSS) before the intervention (T1), immediately after intervention (T2) and 1 month after the intervention (T3). Meanwhile, according to the results of VFSS, Rosenbek penetration aspiration scale (PAS), the moving distance of hyoid bone towards the superior side (H), and pharyngeal response time (T) were analyzed and evaluated. After intervention, all three groups showed significant improvement in post-treatment scores from baseline (P = 0.000). The results of DHI, PAS and H showed that the improvement in high group and high-low group was significantly greater than sham group (P = 0.000). The results of FOIS and T showed that the improvement of bilateral high-frequency group was significantly greater than that of high-low group and sham group (P = 0.000), and the difference lasted until 1 month after the end of treatment. Therefore, bilateral pharyngeal cortex high frequency rTMS and affected side high frequency/unaffected side low frequency rTMS can effectively improve swallowing disorder after acute stroke. However, the effect of bilateral high frequency rTMS is significantly higher than high-low in improving oral feeding function and pharyngeal response time.

Potential mechanisms of cerebrovascular diseases in COVID-19 patients.

Since the outbreak of coronavirus disease 2019 (COVID-19) in 2019, it is gaining worldwide attention at the moment. Apart from respiratory manifestations, neurological dysfunction in COVID-19 patients, especially the occurrence of cerebrovascular diseases (CVD), has been intensively investigated. In this review, the effects of COVID-19 infection on CVD were summarized as follows: (I) angiotensin-converting enzyme 2 (ACE2) may be involved in the attack on vascular endothelial cells by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), leading to endothelial damage and increased subintimal inflammation, which are followed by hemorrhage or thrombosis; (II) SARS-CoV-2 could alter the expression/activity of ACE2, consequently resulting in the disruption of renin-angiotensin system which is associated with the occurrence and progression of atherosclerosis; (III) upregulation of neutrophil extracellular traps has been detected in COVID-19 patients, which is closely associated with immunothrombosis; (IV) the inflammatory cascade induced by SARS-CoV-2 often leads to hypercoagulability and promotes the formation and progress of atherosclerosis; (V) antiphospholipid antibodies are also detected in plasma of some severe cases, which aggravate the thrombosis through the formation of immune complexes; (VI) hyperglycemia in COVID-19 patients may trigger CVD by increasing oxidative stress and blood viscosity; (VII) the COVID-19 outbreak is a global emergency and causes psychological stress, which could be a potential risk factor of CVD as coagulation, and fibrinolysis may be affected. In this review, we aimed to further our understanding of CVD-associated COVID-19 infection, which could improve the therapeutic outcomes of patients. Personalized treatments should be offered to COVID-19 patients at greater risk for stroke in future clinical practice.

NDRG4 prevents cerebral ischemia/reperfusion injury by inhibiting neuronal apoptosis.

Cerebral ischemia is a major cause of mortality and long-term morbidity worldwide. NDRG4 has been shown to protect against cerebral ischemia, although the underlying mechanisms remain largely unclear. Here we found that NDRG4 expression was decreased in the brain tissues of ischemia/reperfusion (IR) rats, indicating increased apoptosis rates among cerebral cells. NDRG4 restoration via an adenovirus significantly attenuated cerebral infarct sizes and impairments in IR rats. Furthermore, adenovirus-mediated NDRG4 inhibited cell apoptosis in the brains of IR rats and regulated the expression of Bcl-2, Bax, caspase-3, and c-Fos. Moreover, we found that NDRG4 increased expression of BDNF, which is strongly related to cerebral ischemia and cellular apoptosis. Altogether, our findings demonstrate that NDRG4 protects cerebral IR injury by inhibiting cell apoptosis and regulates cerebral cell apoptosis by increasing BDNF expression. These results suggest that NDRG4 may be a therapeutic target for IR treatment.

NDRG4 protects against cerebral ischemia injury by inhibiting p53-mediated apoptosis.

Cerebral ischemia is one of the leading causes of death and long-term disability worldwide. N-myc downstream-regulated gene 4 (NDRG4) is predominantly expressed in the brain as well as in the heart and has been reported to be involved in resistance to neuronal cell death caused by ischemic injury. However, the underlying mechanism of NDRG4 in cerebral ischemia/reperfusion (I/R) injury remains unknown. Middle cerebral artery occlusion (MCAO) surgery was performed to establish a model of ischemic brain injury. We found that NDRG4 expression was upregulated during the early stage and decreased 24 h after ischemia/reperfusion (I/R) injury, and NDRG4 overexpression decreased the infarct size and mitigated the neurological deficits induced by I/R injury by inhibiting apoptosis. Furthermore, NDRG4 could interact with p53, inhibiting its expression and blocking p53-mediated mitochondrial apoptosis signaling. Moreover, p53 in turn inhibited NDRG4 expression in response to I/R injury, and inhibition of p53 alleviated cerebral I/R injury. Thus, our work provides a new mechanism for the role of NDRG4 in cerebral I/R injury and provides potential targets for future clinical therapies for stroke.

Trehalose prevents sciatic nerve damage to and apoptosis of Schwann cells of streptozotocin-induced diabetic C57BL/6J mice.

Type 1 diabetes (T1DM) affects approximately 1 in 500 children. Diabetic peripheral neuropathy (DPN) is the most common form of peripheral neuropathy in diabetes and is a significant risk factor for serious pathological change. It is difficult and costly to treat DPN and although there have been several pivotal trials. The development of new drugs to treat DPN remains a high priority. Trehalose is a naturally occurring disaccharide, which is indicated to prevent maternal type 1 diabetes-induced neural tube defects. Thus, the primary aim of this study is to determine whether trehalose ameliorates DPN-induced sciatic nerve injury in TIDM. To establish a T1DM mouse model, wild-type (WT) male C57BL/6 J mice were injected with streptozotocin (STZ). WT mice, T1DM mice, and mice fed with trehalose were assayed for myelin-related gene expression and with behavioral tests. To mimic high glucose in vivo, Schwann cells were cultured under high glucose conditions with or without trehalose. In addition, oxidative damage, apoptosis, and mitochondrial translocation of the pro-apoptotic B-cell lymphoma-2 (Bcl-2) family members were assessed in Schwann cells. Results showed that treatment by trehalose prevented DPN and preserved diabetes-decreased expression of myelin-related genes in T1DM mice. Furthermore, trehalose abolished diabetes-suppressed regeneration of the sciatic nerve. More importantly, trehalose suppressed high glucose-induced oxidative damage and apoptosis in Schwann cells. In summary, trehalose ameliorates DPN-induced sciatic nerve injury in T1DM by preventing apoptosis, which makes it a promising candidate for the treatment of DPN.

Gadd45b prevents autophagy and apoptosis against rat cerebral neuron oxygen-glucose deprivation/reperfusion injury.

Autophagic (type II) cell death has been suggested to play pathogenetic roles in cerebral ischemia. Growth arrest and DNA damage response 45b (Gadd45b) has been shown to protect against rat brain ischemia injury through inhibiting apoptosis. However, the relationship between Gadd45b and autophagy in cerebral ischemia/reperfusion (I/R) injury remains uncertain. The aim of this study is to investigate the effect of Gadd45b on autophagy. We adopt the oxygen-glucose deprivation and reperfusion (OGD/R) model of rat primary cortex neurons, and lentivirus interference used to silence Gadd45b expression. Cell viability and injury assay were performed using CCK-8 and LDH kit. Autophagy activation was monitored by expression of ATG5, LC3, Beclin-1, ATG7 and ATG3. Neuron apoptosis was monitored by expression of Bcl-2, Bax, cleaved caspase3, p53 and TUNEL assay. Neuron neurites were assayed by double immunofluorescent labeling with Tuj1 and LC3B. Here, we demonstrated that the expression of Gadd45b was strongly up-regulated at 24 h after 3 h OGD treatment. ShRNA-Gadd45b increased the expression of autophagy related proteins, aggravated OGD/R-induced neuron cell apoptosis and neurites injury. ShRNA-Gadd45b co-treatment with autophagy inhibitor 3-methyladenine (3-MA) or Wortmannin partly inhibited the ratio of LC3II/LC3I, and slightly ameliorated neuron cell apoptosis under OGD/R. Furthermore, shRNA-Gadd45b inhibited the p-p38 level involved in autophagy, but increased the p-JNK level involved in apoptosis. ShRNA-Gadd45b co-treatment with p38 inhibitor obviously induced autophagy. ShRNA-Gadd45b co-treatment with JNK inhibitor alleviated neuron cell apoptosis. In conclusion, our data suggested that Gadd45b inhibited autophagy and apoptosis under OGD/R. Gadd45b may be a common regulatory protein to control autophagy and apoptosis.

Magnesium sulfate treatment improves outcome in patients with subarachnoid hemorrhage: a meta-analysis study.

OBJECTIVE: To elucidate the role of magnesium sulfate in patients with subarachnoid hemorrhagic (SAH) brain injury METHOD: Studies for the meta-analysis were identified from PubMed (1966 to 2009), Embase (1980 to 2009), and two Chinese journals (1989 to 2009). Paper selection was based on randomized controlled trials comparing magnesium sulfate to placebo treatment in patients with SAH. Two independent review authors extracted the data and assessed trial quality. Meta-analysis was performed using the Cochrane Review Manger software. RESULTS: Five trials involving 482 patients were included in the review. Magnesium sulfate reduced the risk of poor outcome and reduced the occurrence of delayed cerebral ischemia. In the treatment groups, relative risk for poor outcome was 0.73 (CI 0.57-0.93) and 0.66 (CI 0.47-0.92) for delayed cerebral ischemia. Case fatality assessment at three to six months did not show statistically significant data (RR 0.88; CI 0.61-1.29). CONCLUSION: Magnesium sulfate appears to be an effective treatment option in the management of SAH. Further clinical trials are needed before magnesium sulfate can become a routine treatment for SAH.