Matrix metalloproteinase-9 may be a potential therapeutic target in epilepsy

Epileptogenesis is defined as the process of developing epilepsy - a disorder characterized by recurrent seizures - following an initial insult. Neuronal death, aberrant synaptic plasticity and neuroinflammation play essential roles in epileptogenesis. An effective neuroprotective therapeutic agent should counteract one or, ideally, all the above-mentioned mechanisms. However, antiepileptic drugs obtainable nowadays can only suppress seizures, without antiepileptogenic effects. Matrix metalloproteinase-9 (MMP-9) is a member of matrix metalloproteinase (MMP) family that remodels the extracellular matrix. Recently, cumulative evidence indicates that MMP-9, a key participant in neuronal death, aberrant synaptic plasticity and neuroinflammation, is upregulated in experimental epilepsy models. Increased MMP-9 is also implicated in clinical epilepsy studies. Thus, we hypothesize that MMP-9 may be a novel therapeutic target for epilepsy and some agents, such as S24994, atorvastatin and minocycline, may be potential antiepileptogenic drugs.     

The potential of monoclonal antibodies to reduce reperfusion injury in myocardial infarction

Reperfusion injury is mediated, in part, by the accumulation of platelets and leucocytes in the microvasculature after reflow. These components of the blood pool form aggregates that can obstruct flow in small vessels. In addition, mediators released from leucocytes and platelets further damage the reperfused myocardium. A strategy to limit reperfusion injury exploits the important role of membrane-bound adhesion molecules that attach platelets and leucocytes to themselves and to the vascular endothelium. Monoclonal antibodies against specific adhesion receptors effectively eliminate the function of the receptor. The most widely investigated receptors are P-selectin, present on platelets and the endothelium, CD11/CD18, present on leucocytes, and the fibrinogen receptor on platelets. Numerous animal studies have strongly supported the use of these monoclonal antibodies to block adhesion receptors as adjunctive reperfusion therapy. However, recent human trials have yielded disappointing results.     

Cholinergic agonists may produce preservation of myocardial ischaemia/reperfusion injury

The best treatment for myocardial infarction is to restore blood flow in the ischaemic region, though it will bring new myocardial damage known as myocardial ischaemia/reperfusion (I/R) injury. Both the ischaemia preconditioning and the ischaemia postcondioning have been shown to reduce the myocardial I/R injury, but their deficits restrict wide clinical availability. It has been demonstrated that inflammation plays a critical role in the I/R injury process. Also plasma levels of cytokines and inflammation response can be regulated by specifically augmenting cholinergic signaling via the efferent vagus nerve and α7 subunit-containing nicotinic acetylcholine receptor (α7nAChR). Because cholinergic modalities, acting through vagus nerve- and/or α7nAChR-mediated mechanism, have been confirmed to suppress excessive inflammation during the I/R injury in kidney, liver, lung and intestine, therefore, we hypothesize that cholinergic agonists may also provide a protection for the myocardial I/R injury.     

Infusion of routinely stored blood may limit reperfusion injury to acutely ischemic myocardial cells

Emergency thrombolysis and restoration of blood supply to acutely ischemic myocardium kills many reversibly injured muscle cells by free radicals generation and calcium influx. Such reversibly injured cells form the major bulk during the initial 10-20 min of ischaemia and in an era where emergency recanalization of arteries is possible, reperfusion injury becomes significant. Therefore, researchers have been trying to find out ways to limit the reperfusion injury by using antioxidants, complement inhibitors or by reperfusion of leucodepleted autologous blood. Red cell concentrates routinely available in blood banks are already depleted of plasma and hence calcium (chelated to the anticoagulant), leukocytes and most viable plasma proteins including complement. They have reduced oxygen content by virtue of storage; hence there might be less free radical generation. So infusion of such a blood through an intracoronary catheter might limit reperfusion injury. Addition of antioxidants or controlling the oxygen content while infusing this blood might give additional benefits. This hypothesis might be tested in animals by inducing controlled ischaemia with reperfusion of homologous cross-matched and group tested blood followed by cardiac radioactive scans. If the experimental results permit, clinical trials might be carried out eventually.     

CLEC5A expression can be triggered by spike glycoprotein and may be a potential target for COVID-19 therapy

The immune response is crucial for coronavirus disease 19 (COVID-19) progression, with the participation of proinflammatory cells and cytokines, inducing lung injury and loss of respiratory function. CLEC5A expression on monocytes can be triggered by viral and bacterial infections, leading to poor outcomes. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is able to induce neutrophil activation by CLEC5A and Toll-like receptor 2, leading to an aggressive inflammatory cascade, but little is known about the molecular interactions between CLEC5A and SARS-CoV-2 proteins. Here, we aimed to explore how CLEC5A expression could be affected by SARS-CoV-2 infection using immunological tools with in vitro, in vivo, and in silico assays. The findings revealed that high levels of CLEC5A expression were found in monocytes from severe COVID-19 patients in comparison with mild COVID-19 and unexposed subjects, but not in vaccinated subjects who developed mild COVID-19. In hamsters, we detected CLEC5A gene expression during 3–15 days of Omicron strain viral challenge. Our results also showed that CLEC5A can interact with SARS-CoV-2, promoting inflammatory cytokine production, probably through an interaction with the receptor-binding domain in the N-acetylglucosamine binding site (NAG-601). The high expression of CLEC5A and high levels of proinflammatory cytokine production were reduced in vitro by a human CLEC5A monoclonal antibody. Finally, CLEC5A was triggered by spike glycoprotein, suggesting its involvement in COVID-19 progression; therapy with a monoclonal antibody could be a good strategy for COVID-19 treatment, but vaccines are still the best option to avoid hospitalization/deaths.     

地高辛抗血清拮抗内洋地黄素介导的离体大鼠心肌缺氧复氧损伤的实验研究

目的：研究内洋地黄素在离体大鼠心脏缺氧复氧损伤中的变化，观察内洋地黄素特异性拮抗剂地高辛抗血清对大鼠心脏缺氧复氧损伤（A-RI）的拮抗作用。 方法： 制备离体大鼠心脏A-RI模型，60只SD 大鼠随机分为6组，每组10只。正常对照组：给予富氧K-H液灌流，流量10 mL·min-1，持续灌流90 min；A-RI组：富氧K-H液灌流30 min后，予以乏氧K-H液低流量（1-2 mL·min-1）灌流30 min，再给予富氧K-H液复灌30 min；维拉帕米组、小剂量、中剂量、大剂量地高辛抗血清组：于复氧前分别向灌流液中加入维拉帕米5 μg·kg-1、地高辛抗血清3.3 mg·kg-1、10 mg·kg-1、30 mg·kg-1，复氧灌流前灌注完，其余同A-RI组。各组于复氧灌流结束时，制备心肌匀浆，测定心肌匀浆中内洋地黄素含量、细胞膜Na+-K+-ATP酶活性以及线粒体总Ca2+水平，并观察心肌超微结构的变化。 结果： A-RI组心肌组织内洋地黄素水平明显高于正常对照组［（1.04±0.42）ng·g-1与（0.63±0.09）ng·g-1，P<0.01］，细胞膜Na+-K+-ATP酶活性明显低于正常对照组［（2.85±1.00) mmol·g-1Pr·h-1与（4.24±1.19)mmol·g-1Pr·h-1，P<0.01］，线粒体总Ca2+水平显著高于正常对照组［（0.368±0.113) μmol·g-1Pr·h-1与（0.130±0.004) μmol·g-1Pr·h-1，P<0.01］，心肌组织结构发生明显破坏。中、大剂量地高辛抗血清组心肌组织内洋地黄素水平显著低于A-RI组［（0.55±0.24)ng·g-1，(0.68±0.26) ng·g-1］，心肌组织Na+-K+-ATP酶活性显著高于A-RI组［（4.88±1.51)mmol·g-1Pr·h-1，（3.85±1.15)mmol·g-1Pr·h-1），心肌线粒体内总Ca2+含量显著低于A-RI组［（0.127±0.026)nmol·g-1Pr·h-1，（0.156±0.050)μmol·g-1Pr·h-1］，显著减轻A-RI导致的心肌组织结构的损伤。 结论： 地高辛抗血清对A-RI心肌有明显的保护作用，其作用机制可能通过拮抗内洋地黄素，恢复心肌细胞膜Na+-K+-ATP酶活性，减轻细胞内钙超载。     

Proteasome inhibitors protect the steatotic and non-steatotic liver graft against cold ischemia reperfusion injury

Background

The dramatic shortage of organs leads to consider the steatotic livers for transplantation although their poor tolerance against ischemia reperfusion injury (IRI). Ubiquitin proteasome system (UPS) inhibition during hypothermia prolongs myocardial graft preservation. The role of UPS in the liver IRI is not fully understood. Bortezomib (BRZ) treatment at non-toxic doses of rats fed alcohol chronically has shown protective effects by increasing liver antioxidant enzymes. We evaluated and compared both proteasome inhibitors BRZ and MG132 in addition to University of Wisconsin preservation solution (UW) at low and non-toxic dose for fatty liver graft protection against cold IRI.

Experimental

Steatotic and non-steatotic livers have been stored in UW enriched with BRZ (100 nM) or MG132 (25 μM), for 24 h at 4 °C and then subjected to 2-h normothermic reperfusion (37 °C). Liver injury (AST/ALT), hepatic function (bile output; vascular resistance), mitochondrial damage (GLDH), oxidative stress (MDA), nitric oxide (NO) (e-NOS activity; nitrates/nitrites), proteasome chymotrypsin-like activity (ChT), and UPS (19S and 20S5 beta) protein levels have been measured.

Results

ChT was inhibited when BRZ and MG132 were added to UW. Both inhibitors prevented liver injury (AST/ALT), when compared to UW alone. BRZ increased bile production more efficiently than MG132. Only BRZ decreased vascular resistance in fatty livers, which correlated with an increase in NO generation (through e-NOS activation) and AMPK phosphorylation. GLDH and MDA were also prevented by BRZ. In addition, BRZ inhibited adiponectin, IL-1, and TNF alpha, only in steatotic livers.

Conclusion

MG132 and BRZ, administrated at low and non toxic doses, are very efficient to protect fatty liver grafts against cold IRI. The benefits of BRZ are more effective than those of MG132. This evidenced for the first time the potential use of UPS inhibitors for the preservation of marginal liver grafts and for future applications in the prevention of IRI.     

骨髓间充质干细胞治疗肾缺血再灌注损伤的旁分泌机制

背景：骨髓间充质干细胞已用于肾缺血再灌注损伤修复的实验动物研究。 目的：探讨骨髓间充质干细胞治疗肾缺血再灌注损伤的旁分泌机制。 方法：体外培养、纯化并体外DAPI标记大鼠骨髓间充质干细胞,经下腔静脉移植入肾缺血再灌注损伤模型大鼠体内,观察骨髓间充质干细胞对肾缺血再灌注损伤肾功能的保护作用以及在受体鼠体内的迁移情况,并应用免疫组织化学法检测骨髓间充质干细胞治疗后第2天缺血肾脏组织中血管内皮生长因子、肿瘤坏死因子α细胞因子的表达。 结果与结论：与注射生理盐水的对照组比较,细胞移植组大鼠血清肌酐和尿素氮水平在移植后第1、2天明显降低(P < 0.05),但细胞移植组移植后第1、2天肾组织中均未见DAPI阳性细胞;第3、4天则逐渐可见DAPI阳性细胞。免疫组织化学染色结果显示,与对照组相比,移植后第2天肾组织中可见较多血管内皮生长因子阳性细胞,而肾组织中肿瘤坏死因子α阳性细胞明显减少。结果显示旁分泌机制参与了骨髓间充质干细胞治疗肾缺血再灌注损伤。     

Lipoxin receptor agonist, may be a potential treatment for hemorrhagic shock-induced acute lung injury

The main pathogenesis of acute lung injury induced by hemorrhagic shock is increasingly recognized as an inflammatory process. BML-111, a lipoxin receptor agonist, has been demonstrated to promote acute inflammatory resolution by reduction of pro-inflammatory cytokines, attenuation of neutrophilic infiltration, and increasing macrophage phagocytosis of apoptotic neutrophils. Meanwhile, lipoxins and lipoxin analogues have been reported to play pro-resolving and anti-inflammatory effects in many disease models including cerebral ischemia, dorsal air pouch, peritonitis, and so on. Therefore, we hypothesize that BML-111 may be implicated in pathogenesis of hemorrhagic shock-induced acute lung injury.     

Silent myocardial ischemia may be related to inflammatory response

Silent myocardial ischemia (SMI) is a common phenomenon in patients with coronary artery diseases, which frequently occurs at rest, during daily life activities or after physical or emotional exertion. Although individual differences in pain threshold may partially explain the variability in pain perception, the mechanisms responsible for SMI are not well understood. A defective warning mechanism was proposed by some investigators as the reason for the absence of pain, stressing that sensibility to pain differs from patient to patient. A central nervous system as well as peripheral nerve endings alteration was also posited. There is increasing evidence that the development of atherosclerosis is associated with inflammation, and increased levels of inflammatory markers have been documented in various settings of coronary artery disease. Patients with chronic and stable coronary artery disease have clear evidence of a low-grade inflammation, which is independent of traditional cardiovascular risk factors. A systemic inflammatory response to coronary angioplasty has also been reported after balloon angioplasty and after stent implantation. More recently, intriguing observations have shown that there is a particular biochemical pattern of inflammatory system activation (an increased production of inflammatory cytokines) that explains the lack of anginal symptoms in patients with silent myocardial ischemia. That is, pain perception may result from microenviromental balance between proinflammatory and anti-inflammatory cytokines.     

Endogenous gamma interferon production may protect against hepatic cirrhosis and adminstration of exogenous gamma interferon may protect individuals prone to cirrhosis

Hepatic cirrhosis is characterized by the replacement of normal liver parenchyma by collagenous fibrous tissue. Although hepatocytes in the adult retain the ability to divide, under certain circumstances hepatocyte death leads to replacement with fibroblasts and collagen. Whether a particular form of hepatocyte injury leads to cirrhosis is dependent upon the stimulus for the injury and is also highly variable between individuals. It has recently been shown that gamma interferon inhibits collagen synthesis in vitro and fibrosis in vivo. I suggest that individuals who are prone to hepatic cirrhosis from a given stimulus are low producers of gamma interferon while high gamma interferon producers are relatively protected from cirrhosis. I also hypothesize that exogenous gamma interferon administration may halt or slow the progression of cirrhosis in patients with early progressive cirrhosis. Alternatively, endogenous gamma interferon production could be stimulated in these patients with progressive cirrhosis. One agent which may be useful for inducing endogenous gamma interferon is GE-132, an organogermanium.     

Local and remote ischemic preconditioning protect against intestinal ischemic/reperfusion injury after supraceliac aortic clamping

OBJECTIVES:

This study tests the hypothesis that local or remote ischemic preconditioning may protect the intestinal mucosa against ischemia and reperfusion injuries resulting from temporary supraceliac aortic clamping.

METHODS:

Twenty-eight Wistar rats were divided into four groups: the sham surgery group, the supraceliac aortic occlusion group, the local ischemic preconditioning prior to supraceliac aortic occlusion group, and the remote ischemic preconditioning prior to supraceliac aortic occlusion group. Tissue samples from the small bowel were used for quantitative morphometric analysis of mucosal injury, and blood samples were collected for laboratory analyses.

RESULTS:

Supraceliac aortic occlusion decreased intestinal mucosal length by reducing villous height and elevated serum lactic dehydrogenase and lactate levels. Both local and remote ischemic preconditioning mitigated these histopathological and laboratory changes.

CONCLUSIONS:

Both local and remote ischemic preconditioning protect intestinal mucosa against ischemia and reperfusion injury following supraceliac aortic clamping.     

羟苯氨酮保护麻醉猫心对抗缺血与再灌注损伤

目的确定羟苯氨酮对在体心脏缺血-再灌注损伤的对抗作用。方法建立麻醉猫心冠脉前降支阻断30 min,再灌60 min的模型,从心脏血流动力学、心外膜心电图(Epi-ECG)、心肌能量代谢、血清丙二醛(MDA)含量、肌酸磷酸激酶(CPK)与谷草转氨酶(GOT)活性等方面评价羟苯氨酮的保护作用。结果静注羟苯氨酮2.0~8.4 mg/kg剂量依赖性地减慢心率(HR),降低血压(MAP)、心脏作功和外周血管阻力(SVR),减轻以Epi-ECG ST段升高为指标的心肌缺血反应,对抗再灌注引起的缺血区心肌三磷酸腺苷(ATP)与磷酸肌酸(PCr)含量及ATP/Pi、PCr/Pi比值减少和血清MDA含量、CPK与GOT活性升高,并使之保持在正常水平。结论羟苯氨酮明显保护在体心脏对抗心肌缺血-再灌注损伤。     

Mycobacterium tuberculosis infection may protect against allergy in a tuberculosis endemic area

BACKGROUND: Epidemiological studies have shown an inverse relation of mycobacterial infection and the frequency of allergic diseases and asthma. Recent evidence suggests that allergic inflammation may be inhibited in the presence of chronic and persistent infections, such as that by Mycobacterium tuberculosis (MTB). The relation of tuberculin skin test (TST) size, an accepted marker of MTB infection and the frequency of allergic disease symptoms has not been reported from an area where MTB infection is endemic. OBJECTIVE: To investigate the association of TST and allergic disease symptoms, in children living in a tuberculosis (TB) endemic area. METHODS: In this cross-sectional study, 841 children aged 6-14 years from randomly selected household addresses in two poor communities of Cape Town, South Africa, were investigated with TST and standardized International Study on Asthma and Allergies in Childhood-based questionnaire on allergic disease symptoms. RESULTS: Children with positive TST (> or =10 mm) were significantly less likely to have allergic disease symptoms, in particular allergic rhinitis (AR) (adjusted odds ratio 0.43; 95% confidence interval 0.24-0.79) than those with negative TST. This association remained significant after adjusting for possible confounders and correcting for the effect of clustering (>1 child per household address) in the sample. There was a significant inverse linear trend in the relation of TST size in millimetre and the frequency of allergic disease symptoms, in particular AR (P<0.001). CONCLUSIONS: These results of inverse association of strong TST reaction and allergic disease symptoms in children from a TB endemic area are in support of the hypotheses that allergic inflammation may be inhibited by chronic infections, such as MTB.