Overexpression of copper and zinc superoxide dismutase in transgenic mice prevents the induction and activation of matrix metalloproteinases after cold injury-induced brain trauma

The role of reactive oxygen species in the regulation of the blood-brain barrier

The blood-brain barrier (BBB) regulates the exchange of metabolites and cells between the blood and brain, and maintains central nervous system homeostasis. Various factors affect BBB barrier functions, including reactive oxygen species (ROS). ROS can act as stressors, damaging biological molecules, but they also serve as secondary messengers in intracellular signaling cascades during redox signaling. The impact of ROS on the BBB has been observed in multiple sclerosis, stroke, trauma, and other neurological disorders, making blocking ROS generation a promising therapeutic strategy for BBB dysfunction. However, it is important to consider ROS generation during normal BBB functioning for signaling purposes. This review summarizes data on proteins expressed by BBB cells that can be targets of redox signaling or oxidative stress. It also provides examples of signaling molecules whose impact may cause ROS generation in the BBB, as well as discusses the most common diseases associated with BBB dysfunction and excessive ROS generation, open questions that arise in the study of this problem, and possible ways to overcome them.

Zinc's Association with the CmPn/CmP Signaling Network in Breast Cancer Tumorigenesis

It is well-known that serum and cellular concentrations of zinc are altered in breast cancer patients. Specifically, there are notable zinc hyper-aggregates in breast tumor cells when compared to normal mammary epithelial cells. However, the mechanisms responsible for zinc accumulation and the consequences of zinc dysregulation are poorly understood. In this review, we detailed cellular zinc regulation/dysregulation under the influence of varying levels of sex steroids and breast cancer tumorigenesis to try to better understand the intricate relationship between these factors based on our current understanding of the CmPn/CmP signaling network. We also made some efforts to propose a relationship between zinc signaling and the CmPn/CmP signaling network.

Early Transcriptional Changes of Adipose-Derived Stem Cells (ADSCs) in Cell Culture

Background and Objectives: While autologous fat grafting has been carried out in the clinical field for many years, the utilization of isolated and cultured adipose-derived stem cells (ADSCs) is highly restricted in many countries. However, ADSCs are under investigation currently and heavily researched in many cell-based therapy approaches in the field of regenerative medicine. Objective: For the utilization of future cell-based therapies with ADSCs, in vitro cell expansion might be necessary in many cases. Thus, the cellular characteristics of ADSCs may be altered though the process of being cultured. The aim of this study was to assess changes in the gene expression profile of ADSCs after cell expansion for 48 h. Materials and Methods: Isolated ADSCs from five different donors were used for in vitro expansion. For the evaluation of the gene expression profile, mRNA deep Next-Generation Sequencing was performed to evaluate the differences between cultured and freshly isolated cells. Results: Our study gives insight into transcriptional changes in ADSCs after a short cell cultivation period. This includes the most prominent upregulated genes such as PPL, PRR15, CCL11 and ABCA9, as well the most downregulated genes, which are FOSB, FOS, EGR1 and DUSP6. Furthermore, we showed different biological processes that changed during short-term cell expansion, which led to downregulation of fat-associated metabolism hormone processes and to an upregulation of extracellular matrix-associated genes. Conclusion: In conclusion, our study reveals a detailed insight into early changes in the gene expression profile of cultured ADSCs. Our results can be utilized in future experiments.

Secondary Brain Injury by Oxidative Stress After Cerebral Hemorrhage: Recent Advances

Intracerebral hemorrhage (ICH) is a clinical syndrome in which blood accumulates in the brain parenchyma because of a nontraumatic rupture of a blood vessel. Because of its high morbidity and mortality rate and the lack of effective therapy, the treatment of ICH has become a hot research topic. Meanwhile, Oxidative stress is one of the main causes of secondary brain injury(SBI) after ICH. Therefore, there is a need for an in-depth study of oxidative stress after ICH. This review will discuss the pathway and effects of oxidative stress after ICH and its relationship with inflammation and autophagy, as well as the current antioxidant therapy for ICH with a view to deriving better therapeutic tools or targets for ICH.

Modulation of Reactive Oxygen Species Homeostasis as a Pleiotropic Effect of Commonly Used Drugs

Age-associated diseases represent a growing burden for global health systems in our aging society. Consequently, we urgently need innovative strategies to counteract these pathological disturbances. Overwhelming generation of reactive oxygen species (ROS) is associated with age-related damage, leading to cellular dysfunction and, ultimately, diseases. However, low-dose ROS act as crucial signaling molecules and inducers of a vaccination-like response to boost antioxidant defense mechanisms, known as mitohormesis. Consequently, modulation of ROS homeostasis by nutrition, exercise, or pharmacological interventions is critical in aging. Numerous nutrients and approved drugs exhibit pleiotropic effects on ROS homeostasis. In the current review, we provide an overview of drugs affecting ROS generation and ROS detoxification and evaluate the potential of these effects to counteract the development and progression of age-related diseases. In case of inflammation-related dysfunctions, cardiovascular- and neurodegenerative diseases, it might be essential to strengthen antioxidant defense mechanisms in advance by low ROS level rises to boost the individual ROS defense mechanisms. In contrast, induction of overwhelming ROS production might be helpful to fight pathogens and kill cancer cells. While we outline the potential of ROS manipulation to counteract age-related dysfunction and diseases, we also raise the question about the proper intervention time and dosage.

Changes in global gene expression indicate disordered autophagy, apoptosis and inflammatory processes and downregulation of cytoskeletal signalling and neuronal development in patients with Niemann-Pick C disease

Changes in gene expression profiles were investigated in 23 patients with Niemann-Pick C1 disease (NPC). cDNA expression microarrays with subsequent validation by qRT-PCR were used. Comparison of NPC to control samples revealed upregulation of genes involved in inflammation (MMP3, THBS4), cytokine signalling (MMP3), extracellular matrix degradation (MMP3, CTSK), autophagy and apoptosis (CTSK, GPNMB, PTGIS), immune response (AKR1C3, RCAN2, PTGIS) and processes of neuronal development (RCAN2). Downregulated genes were associated with cytoskeletal signalling (ACTG2, CNN1); inflammation and oxidative stress (CNN1); inhibition of cell proliferation, migration and differentiation; ERK-MAPK pathway (COL4A1, COL4A2, CPA4); cell adhesion (IGFBP7); autophagy and apoptosis (CDH2, IGFBP7, COL4A2); neuronal function and development (CSRP1); and extracellular matrix stability (PLOD2). When comparing NPC and Gaucher patients together versus controls, upregulation of SERPINB2 and IL13RA2 and downregulation of CSRP1 and CNN1 were characteristic. Notably, in NPC patients, the expression of PTGIS is upregulated while the expression of PLOD2 is downregulated when compared to Gaucher patients or controls and potentially could serve to differentiate these patients. Interestingly, in NPC patients with (i) jaundice, splenomegaly and cognitive impairment/psychomotor delay-the expression of ACTG2 was especially downregulated; (ii) ataxia-the expression of ACTG2 and IGFBP5 was especially downregulated; and (iii) VSGP, dysarthria, dysphagia and epilepsy-the expression of AKR1C3 was especially upregulated while the expression of ACTG2 was downregulated. These results indicate disordered apoptosis, autophagy and cytoskeleton remodelling as well as upregulation of immune response and inflammation to play an important role in the pathogenesis of NPC in humans.

Differential mRNA expression combined with network pharmacology reveals network effects of Liangxue Tongyu Prescription for acute intracerebral hemorrhagic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Liangxue Tongyu Prescription (LTP) is a traditional Chinese medicine formula composed of 8 crude drugs that is widely used to treat acute intracerebral hemorrhage (AICH).

AIM OF THE STUDY

To verify the efficacy of LTP on the survival time in the treatment of acute intracerebral hemorrhagic rats (AICHs), and to elucidate its network pharmacodynamic mechanism of multi-component, multi-target, and multi-signaling pathways.

MATERIALS AND METHODS

Survival analysis was used to evaluate the survival time of AICH rats induced by different doses of collagenase and the efficacy of three doses of LTP in the treatment of AICH rats. The Kaplan-Meier curves for survival time were produced and compared with the Log-rank test and Wilcoxon (Gehan) χ². Differential mRNA-seq combined with network pharmacology was used to disclose the network effect mechanism of LTP on AICH, and the obtained differential genes were mapped into the predictive empirical compound-target network model (ECT network model) and the empirical compound-target-pathogenesis (disease) network model (ECTP network model).

RESULTS

The median survival time of four different doses of LTP-treated groups (0.00 g/kg, 5.78 g/kg, 11.55 g/kg, 23.10 g/kg) for adult AICH rats by 0.18 U collagenase was 14 h, 37 h, 150 h, and 51 h respectively, and the 7-day survival rates were 33.3%, 41.7%, 50.0%, and 38.5%, of which the medium-dose group (MD) had a longer survival time and higher survival rate. Through further validation experiments, the MD group had a better efficacy trend with a median survival time of 168 h vs 23 h in the model control group (MC) (Wilcoxon Gehan Test, χ² = 3.478, P = 0.062). The transcriptomic analysis of mRNA showed that 583 significant differential genes were found between the MC and MD group and 7 key therapeutic targets regulated by 29 compounds in LTP on AICH were screened out by VCT and VCTP network model. These targets were involved in 5 regulatory models or pathways.

CONCLUSION

Our study confirmed the exact efficacy of the LTP in the treatment of AICH and revealed the potential pharmacodynamic components and mode of action of the LTP on AICH. Using differential transcriptome of mRNA combined with network pharmacology, we screened out 29 chemical compounds as the potential effective ingredients of LTP which acted on 7 targets of AICH involving 5 pathological pathways, mainly including repairing the brain function defect, improving neural function, protecting blood-brain barrier from damage, reducing inflammatory factors, and inhibiting apoptosis. The present study not only provides a new explanation for the 'multi-component, multi-target, multi-pathway' effects of the LTP on AICH but also screened out some major compounds of LTP and their potential targets which will facilitate the development of new drugs for AICH.

Neuroinflammation, oxidative stress, and blood-brain barrier (BBB) disruption in acute Utah electrode array implants and the effect of deferoxamine as an iron chelator on acute foreign body response

The use of intracortical microelectrode arrays has gained significant attention in being able to help restore function in paralysis patients and study the brain in various neurological disorders. Electrode implantation in the cortex causes vasculature or blood-brain barrier (BBB) disruption and thus elicits a foreign body response (FBR) that results in chronic inflammation and may lead to poor electrode performance. In this study, a comprehensive insight into the acute molecular mechanisms occurring at the Utah electrode array-tissue interface is provided to understand the oxidative stress, neuroinflammation, and neurovascular unit (astrocytes, pericytes, and endothelial cells) disruption that occurs following microelectrode implantation. Quantitative real time polymerase chain reaction (qRT-PCR) was used to quantify the gene expression at acute time-points of 48-hr, 72-hr, and 7-days for factors mediating oxidative stress, inflammation, and BBB disruption in rats implanted with a non-functional 4 × 4 Utah array in the somatosensory cortex. During vascular disruption, free iron released into the brain parenchyma can exacerbate the FBR, leading to oxidative stress and thus further contributing to BBB degradation. To reduce the free iron released into the brain tissue, the effects of an iron chelator, deferoxamine mesylate (DFX), was also evaluated.

Blood brain barrier (BBB)-disruption in intracortical silicon microelectrode implants

Chronically implanted microelectrodes in the neural tissue elicit inflammatory responses that are time varying and have been shown to depend on multiple factors. Among these factors, blood brain barrier (BBB)-disruption has been hypothesized as one of the dominant factors resulting in electrode failure. A series of events that includes BBB and cell-membrane disruption occurs during electrode implantation that triggers multiple biochemical cascades responsible for microglial and astroglial activation, hemorrhage, edema, and release of pro-inflammatory neurotoxic cytokines that causes neuronal degeneration and dysfunction. Typically, microwire arrays and silicon probes are inserted slowly into the neural tissue whereas the silicon Utah MEAs (UMEA) are inserted at a high speed using a pneumatic inserter. In this work, we report the sequelae of electrode-implant induced cortical injury at various acute time points in UMEAs implanted in the brain tissue by quantifying the expression profile for key genes mediating the inflammatory response and tight junction (TJ) and adherens junction (AJ) proteins that form the BBB and are critical to the functioning of the BBB. Our results indicated upregulation of most pro-inflammatory genes relative to naïve controls for all time points. Expression levels for the genes that form the TJ and AJ were downregulated suggestive of BBB-dysfunction. Moreover, there was no significant difference between stab and implant groups suggesting the effects of UMEA insertion-related trauma in the brain tissue. Our results provide an insight into the physiological events related to neuroinflammation and BBB-disruption occurring at acute time-points following insertion of UMEAs.

The influence of oral copper-methionine on matrix metalloproteinase-2 gene expression and activation in right-sided heart failure induced by cold temperature: A broiler chicken perspective

This study was designed to investigate the expression, activation and activity of matrix metalloproteinase-2 (MMP-2) in the heart of broiler chickens reared in cold conditions and fed with copper-methionine supplement at different levels. The chickens (n=480) were randomly allotted to six treatments and four replicates. Treatments included two rearing temperatures (i.e. normal and cold temperatures) each combined with three levels of supplemental copper-methionine (i.e. 0, 100 and 200mg/kg). On d 38 and 45 of age, four broilers from each treatment were sacrificed and their hearts were stored at -80°C. Right-sided heart failure, as evident from abdominal and pericardial fluid accumulation, was observed in broilers under cold stress and not receiving supplemental copper. This clinical observation was confirmed at molecular level through increased MMP-2 expression, activation and activity in this group. Birds reared under normal temperature, however, were not involved in right-sided heart failure nor benefitted from copper-methionine supplementation. In contrast, gelatin zymography and real-time PCR demonstrated that dietary supplementation with copper-methionine decreased pro-MMP-2 and MMP-2 in the heart of chickens reared in cold conditions. However, gelatin reverse zymography did not show any difference between treatments in tissue inhibitor of metalloproteinase-2. Level of supplementation showed similar effects on parameters determined. It is concluded that dietary supplementation with copper-methionine reduced right-sided heart failure at clinical and molecular levels in cold-stressed chickens.

Effects of Dietary Copper-Methionine on Matrix Metalloproteinase-2 in the Lungs of Cold-Stressed Broilers as an Animal Model for Pulmonary Hypertension

The objective of the present study was to investigate the effects of different levels of copper (as supplemental copper-methionine) on ascites incidence and matrix metalloproteinase-2 (MMP-2) changes in the lungs of cold-stressed broilers. For this purpose, 480 1-day-old Ross 308 broiler chickens were randomly assigned to six treatments. Treatments consisted of two ambient temperatures (thermoneutral and cold stress) each combined with 0, 100, and 200 mg supplemental copper/kg as copper-methionine in a 2 × 3 factorial arrangement in a completely randomized design with four replicates. Ascites was diagnosed based on abdominal and pericardial fluid accumulation at 45 days of age. Fourty-eight broilers were killed at 38 and 45 days of age, and their lungs were collected for biological analysis. Results showed that MMP-2 increased in the lungs of ascitic broilers and that copper-methionine supplementation significantly reduced MMP-2 in cold-stressed broiler chickens. Treatments did not affect tissue inhibitor of metalloproteinase-2 (TIMP-2) at 38 and 45 days of age, and no difference was observed between 100 and 200 mg/kg copper-methionine treatments. In conclusion, copper-methionine at higher than conventional levels of supplementation decreased ascites incidence in low temperature through reduced MMP-2 concentration. Further research is warranted to investigate the effect of copper on MMP-2 concentrations in other tissues with high oxygen demand.

Effects of electromagnetic pulse exposure on gelatinase of blood-brain barrier in vitro

The biological effects of electromagnetic pulse (EMP) on the brain have been focused on for years. It was reported that gelatinase played an important role in maintaining brain function through regulating permeability in the blood-brain barrier (BBB). To investigate the effects of EMP on gelatinase of BBB, an in vitro BBB model was established using primary cultured rat brain microvascular endothelial cells (BMVEC), astrocytes and half-contact culture of these cells in a transwell chamber. Cultured supernatant and cells were collected at different time points after exposure to EMP (peak intensity 400 kV/m, rise time 10 ns, pulse width 350 ns, 0.5 pps and 200 pulses). Protein levels of cellular gelatinase MMP-2 and MMP-9, and endogenous inhibitor TIMP-1 and TIMP-2 were detected by Western blot. The activity of gelatinase in culture supernatant was detected by gelatin zymography. It was found that compared with the sham-exposed group, the protein level of MMP-2 was significantly increased at 6 h (p < 0.05), and the protein level of its endogenous inhibitor TIMP-2 did not change after EMP exposure. In addition, the protein levels of MMP-9 and its endogenous inhibitor TIMP-1 did not change after EMP exposure. Gelatin zymography results showed that the activity of MMP-2 in the inner pool and the outer pool of the transwell chamber was significantly increased at 6 h after EMP exposure compared with that of the sham group. These results suggested that EMP exposure could affect the expression and activity of MMP-2 in the BBB model.

Altered cerebrospinal fluid proteins in Smith-Lemli-Opitz syndrome patients

Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive, multiple malformation syndrome with neurocognitive impairment. SLOS arises from mutations in the 7-dehydrocholesterol reductase gene which results in impaired enzymatic conversion of 7-dehydrocholesterol to cholesterol. In the current work, we sought to measure proteins that were altered in the cerebrospinal fluid from SLOS patients compared to pediatric controls. Using a multi-analyte antibody-based assay, we found that 12 proteins are altered in SLOS patients. Validation studies were carried out and the findings from this study suggest alterations in extracellular matrix remodeling and further evidence of oxidative stress within the disease pathophysiology. The results of this study will be used to explore biological pathways altered in SLOS and identifies a set of CSF proteins that can be evaluated as biomarkers in future therapeutic trials. © 2016 Wiley Periodicals, Inc.

Paradoxical Roles of Antioxidant Enzymes: Basic Mechanisms and Health Implications

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are generated from aerobic metabolism, as a result of accidental electron leakage as well as regulated enzymatic processes. Because ROS/RNS can induce oxidative injury and act in redox signaling, enzymes metabolizing them will inherently promote either health or disease, depending on the physiological context. It is thus misleading to consider conventionally called antioxidant enzymes to be largely, if not exclusively, health protective. Because such a notion is nonetheless common, we herein attempt to rationalize why this simplistic view should be avoided. First we give an updated summary of physiological phenotypes triggered in mouse models of overexpression or knockout of major antioxidant enzymes. Subsequently, we focus on a series of striking cases that demonstrate "paradoxical" outcomes, i.e., increased fitness upon deletion of antioxidant enzymes or disease triggered by their overexpression. We elaborate mechanisms by which these phenotypes are mediated via chemical, biological, and metabolic interactions of the antioxidant enzymes with their substrates, downstream events, and cellular context. Furthermore, we propose that novel treatments of antioxidant enzyme-related human diseases may be enabled by deliberate targeting of dual roles of the pertaining enzymes. We also discuss the potential of "antioxidant" nutrients and phytochemicals, via regulating the expression or function of antioxidant enzymes, in preventing, treating, or aggravating chronic diseases. We conclude that "paradoxical" roles of antioxidant enzymes in physiology, health, and disease derive from sophisticated molecular mechanisms of redox biology and metabolic homeostasis. Simply viewing antioxidant enzymes as always being beneficial is not only conceptually misleading but also clinically hazardous if such notions underpin medical treatment protocols based on modulation of redox pathways.

Pathogenesis of brain edema and investigation into anti-edema drugs

Brain edema is a potentially fatal pathological state that occurs after brain injuries such as stroke and head trauma. In the edematous brain, excess accumulation of extracellular fluid results in elevation of intracranial pressure, leading to impaired nerve function. Despite the seriousness of brain edema, only symptomatic treatments to remove edema fluid are currently available. Thus, the development of novel anti-edema drugs is required. The pathogenesis of brain edema is classified as vasogenic or cytotoxic edema. Vasogenic edema is defined as extracellular accumulation of fluid resulting from disruption of the blood-brain barrier (BBB) and extravasations of serum proteins, while cytotoxic edema is characterized by cell swelling caused by intracellular accumulation of fluid. Various experimental animal models are often used to investigate mechanisms underlying brain edema. Many soluble factors and functional molecules have been confirmed to induce BBB disruption or cell swelling and drugs targeted to these factors are expected to have anti-edema effects. In this review, we discuss the mechanisms and involvement of factors that induce brain edema formation, and the possibility of anti-edema drugs targeting them.

Inhibition of acetylcholinesterase modulates NMDA receptor antagonist mediated alterations in the developing brain

Exposure to N-methyl-d-aspartate (NMDA) receptor antagonists has been demonstrated to induce neurodegeneration in newborn rats. However, in clinical practice the use of NMDA receptor antagonists as anesthetics and sedatives cannot always be avoided. The present study investigated the effect of the indirect cholinergic agonist physostigmine on neurotrophin expression and the extracellular matrix during NMDA receptor antagonist induced injury to the immature rat brain. The aim was to investigate matrix metalloproteinase (MMP)-2 activity, as well as expression of tissue inhibitor of metalloproteinase (TIMP)-2 and brain-derived neurotrophic factor (BDNF) after co-administration of the non-competitive NMDA receptor antagonist MK801 (dizocilpine) and the acetylcholinesterase (AChE) inhibitor physostigmine. The AChE inhibitor physostigmine ameliorated the MK801-induced reduction of BDNF mRNA and protein levels, reduced MK801-triggered MMP-2 activity and prevented decreased TIMP-2 mRNA expression. Our results indicate that AChE inhibition may prevent newborn rats from MK801-mediated brain damage by enhancing neurotrophin-associated signaling pathways and by modulating the extracellular matrix.

Hemostasis and alterations of the central nervous system

Modulation of coagulation has been successfully applied to ischemic disorders of the central nervous system (CNS). Some components of the coagulation system have been identified in the CNS, yet with limited exception their functions have not been clearly defined. Little is known about how events within the cerebral tissues affect hemostasis. Nonetheless, the interaction between cerebral cells and vascular hemostasis and the possibility that endogenous coagulation factors can participate in functions within the neurovascular unit provide intriguing possibilities for deeper insight into CNS functions and the potential for treatment of CNS injuries. Here, we consider the expression of coagulation factors in the CNS, the coagulopathy associated with focal cerebral ischemia (and its relationship to hemorrhagic transformation), the use of recombinant tissue plasminogen activator (rt-PA) in ischemic stroke and its study in animal models, the impact of rt-PA on neuron and CNS structure and function, and matrix protease generation and matrix degradation and hemostasis. Interwoven among these topics is evidence for interactions of coagulation factors with and within the CNS. How activation of hemostasis occurs in the cerebral tissues and how the brain responds are difficult questions that offer many research possibilities.

Protective reactivity and alteration of the brain tissue in alcoholics evidenced by SOD1, MMP9 immunohistochemistry, and electron microscopy

Alcohol and its associated oxidative stress is one of the widespread contributors to the brain damage. Matrix metalloproteinases, which are extensively analyzed in brain pathology studies, are not sufficiently investigated in chronic alcohol consumption. This study evaluated regional brain damage caused by oxidative stress. Contribution of metalloproteinase-9 to this affection was evidenced in alcoholic subjects and correlated with ultrastructural changes. The authors found correlation between neuronal expression patterns of superoxide dismutase-1 and metalloproteinase-9 in nigral (r = 0.532, p < 0.001), striatal (r = 0.327, p < 0.001), and cortical (r = 0.306, p < 0.001) regions, and a significant decrease of nigral superoxide dismutase-1 median values accompanied by severe myelin damage.

Bupivacaine induces short-term alterations and impairment in rat tendons

BACKGROUND

Toxicity of the local anesthetic bupivacaine (BV) has been a matter of debate across medical fields. Numerous in vitro studies demonstrate considerable toxicity of BV on various cell types.

PURPOSE

This study addresses the question of how tendon tissue responds to BV in vivo and in vitro.

STUDY DESIGN

Controlled laboratory study.

METHODS

In vitro studies on cultured rat Achilles tendon-derived cells were performed with cell viability assays and cleaved caspase 3 immunocytochemistry. Quantitative reverse transcription-polymerase chain reaction, Western blotting, gelatin zymography, and a biomechanical testing routine were applied on rat Achilles tendons at 1 and 4 weeks after a single unilateral peritendinous injection of 0.5% BV. The BV-mediated cell death in tendons was estimated with terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining and immunohistochemical detection of cleaved caspase 3.

RESULTS

Treatment of rat tendon-derived cells with 0.5% bupivacaine for 10 minutes had detrimental effects on cell viability, which can be reduced by N-acetyl-L-cysteine or reduction of extracellular calcium. In vivo, single peritendinous injections of BV caused apoptosis in endotenon cells and an increase of pro-matrix metalloproteinase-9 after 6 hours. The collagen ratio shifted toward collagen type III after 6 hours and 2 days; scleraxis messenger RNA (mRNA) expression was reduced by 87%. Maximum tensile load was reduced by 17.6% after 1 week.

CONCLUSION

Bupivacaine exerts a severe, reactive oxygen species-mediated effect on tendon cell viability in vitro in a time- and dose-dependent manner, depending on extracellular calcium concentration. Culture conditions need to be taken into account when in vitro data are translated into the in vivo situation. In vivo, administration of BV elicits a marked but temporary functional damage.

CLINICAL RELEVANCE

Local anesthetics cause short-term alterations in rat tendons, which, if occurring in humans to a similar extent, may be relevant regarding decreased biomechanical properties and increased vulnerability to tendon overload or injury.

Moderate systemic hypothermia decreases burn depth progression

BACKGROUND

Therapeutic hypothermia has been proposed to be beneficial in an array of human pathologies including cardiac arrest, stroke, traumatic brain and spinal cord injury, and hemorrhagic shock. Burn depth progression is multifactorial but inflammation plays a large role. Because hypothermia is known to reduce inflammation, we hypothesized that moderate hypothermia will decrease burn depth progression.

METHODS

We used a second-degree 15% total body surface area thermal injury model in rats. Burn depth was assessed by histology of biopsy sections. Moderate hypothermia in the range of 31-33°C was applied for 4h immediately after burn and in a delayed fashion, starting 2h after burn. In order to gain insight into the beneficial effects of hypothermia, we analyzed global gene expression in the burned skin.

RESULTS

Immediate hypothermia decreased burn depth progression at 6h post injury, and this protective effect was sustained for at least 24h. Burn depth was 18% lower in rats subjected to immediate hypothermia compared to control rats at both 6 and 24h post injury. Rats in the delayed hypothermia group did not show any significant decrease in burn depth at 6h, but had 23% lower burn depth than controls at 24h. Increased expression of several skin-protective genes such as CCL4, CCL6 and CXCL13 and decreased expression of tissue remodeling genes such as matrix metalloprotease-9 were discovered in the skin biopsy samples of rats subjected to immediate hypothermia.

CONCLUSIONS

Systemic hypothermia decreases burn depth progression in a rodent model and up-regulation of skin-protective genes and down-regulation of detrimental tissue remodeling genes by hypothermia may contribute to its beneficial effects.

The role of free radicals in traumatic brain injury

Traumatic brain injury (TBI) is a significant cause of death and disability in both the civilian and the military populations. The primary impact causes initial tissue damage, which initiates biochemical cascades, known as secondary injury, that expand the damage. Free radicals are implicated as major contributors to the secondary injury. Our review of recent rodent and human research reveals the prominent role of the free radicals superoxide anion, nitric oxide, and peroxynitrite in secondary brain injury. Much of our current knowledge is based on rodent studies, and the authors identified a gap in the translation of findings from rodent to human TBI. Rodent models are an effective method for elucidating specific mechanisms of free radical-induced injury at the cellular level in a well-controlled environment. However, human TBI does not occur in a vacuum, and variables controlled in the laboratory may affect the injury progression. Additionally, multiple experimental TBI models are accepted in rodent research, and no one model fully reproduces the heterogeneous injury seen in humans. Free radical levels are measured indirectly in human studies based on assumptions from the findings from rodent studies that use direct free radical measurements. Further study in humans should be directed toward large samples to validate the findings in rodent studies. Data obtained from these studies may lead to more targeted treatment to interrupt the secondary injury cascades.

Anti-neuroinflammatory effects of the extract of Achillea fragrantissima

BACKGROUND

The neuroinflammatory process plays a central role in the initiation and progression of neurodegenerative diseases such as Parkinson's and Alzheimer's diseases, and involves the activation of brain microglial cells. During the neuroinflammatory process, microglial cells release proinflammatory mediators such as cytokines, matrix metalloproteinases (MMP), Reactive oxygen species (ROS) and nitric oxide (NO). In the present study, extracts from 66 different desert plants were tested for their effect on lipopolysaccharide (LPS) - induced production of NO by primary microglial cells. The extract of Achillea fragrantissima (Af), which is a desert plant that has been used for many years in traditional medicine for the treatment of various diseases, was the most efficient extract, and was further studied for additional anti-neuroinflammatory effects in these cells.

METHODS

In the present study, the ethanolic extract prepared from Af was tested for its anti-inflammatory effects on lipopolysaccharide (LPS)-activated primary cultures of brain microglial cells. The levels of the proinflammatory cytokines interleukin1β (IL-1β) and tumor necrosis factor-α (TNFα) secreted by the cells were determined by reverse transcriptase-PCR and Enzyme-linked immunosorbent assay (ELISA), respectively. NO levels secreted by the activate cells were measured using Griess reagent, ROS levels were measured by 2'7'-dichlorofluorescein diacetate (DCF-DA), MMP-9 activity was measured using gel zymography, and the protein levels of the proinflammatory enzymes cyclooxygenase-2 (COX-2) and induced nitric oxide synthase (iNOS) were measured by Western blot analysis. Cell viability was assessed using Lactate dehydrogenase (LDH) activity in the media conditioned by the cells or by the crystal violet cell staining.

RESULTS

We have found that out of the 66 desert plants tested, the extract of Af was the most efficient extract and inhibited ~70% of the NO produced by the LPS-activated microglial cells, without affecting cell viability. In addition, this extract inhibited the LPS - elicited expression of the proinflammatory mediators IL-1β, TNFα, MMP-9, COX-2 and iNOS in these cells.

CONCLUSIONS

Thus, phytochemicals present in the Af extract could be beneficial in preventing/treating neurodegenerative diseases in which neuroinflammation is part of the pathophysiology.

Oxidative stress and blood-brain barrier dysfunction under particular consideration of matrix metalloproteinases

A cell's "redox" (oxidation and reduction) state is determined by the sum of all redox processes yielding reactive oxygen species (ROS), reactive nitrogen species (RNS), and other reactive intermediates. Low amounts of ROS/RNS are generated by different mechanisms in every cell and are important regulatory mediators in many signaling processes (redox signaling). When the physiological balance between the generation and elimination of ROS/RNS is disrupted, oxidative/nitrosative stress with persistent oxidative damage of the organism occurs. Oxidative stress has been suggested to act as initiator and/or mediator of many human diseases. The cerebral vasculature is particularly susceptible to oxidative stress, which is critical since cerebral endothelial cells play a major role in the creation and maintenance of the blood-brain barrier (BBB). This article will only contain a focused introduction on the biochemical background of redox signaling, since this has been reported already in a series of excellent recent reviews. The goal of this work is to increase the understanding of basic mechanisms underlying ROS/RNS-induced BBB disruption, with a focus on the role of matrix metalloproteinases, which, after all, appear to be a key mediator in the initiation and progression of BBB damage elicited by oxidative stress.

Extracellular matrix proteases contribute to progression of pelvic organ prolapse in mice and humans

Pelvic organ prolapse (POP) is a common condition affecting almost half of women over the age of 50. The molecular and cellular mechanisms underlying this condition, however, remain poorly understood. Here we have reported that fibulin-5, an integrin-binding matricellular protein that is essential for elastic fiber assembly, regulated the activity of MMP-9 to maintain integrity of the vaginal wall and prevented development of POP. In murine vaginal stromal cells, fibulin-5 inhibited the β1 integrin-dependent, fibronectin-mediated upregulation of MMP-9. Mice in which the integrin-binding motif was mutated to an integrin-disrupting motif (Fbln5RGE/RGE) exhibited upregulation of MMP-9 in vaginal tissues. In contrast to fibulin-5 knockouts (Fbln5-/-), Fbln5RGE/RGE mice were able to form intact elastic fibers and did not exhibit POP. However, treatment of mice with β-aminopropionitrile (BAPN), an inhibitor of matrix cross-linking enzymes, induced subclinical POP. Conversely, deletion of Mmp9 in Fbln5-/- mice significantly attenuated POP by increasing elastic fiber density and improving collagen fibrils. Vaginal tissue samples from pre- and postmenopausal women with POP also displayed significantly increased levels of MMP-9. These results suggest that POP is an acquired disorder of extracellular matrix and that therapies targeting matrix proteases may be successful for preventing or ameliorating POP in women.

Multiple roles of metalloproteinases in neurological disorders

Once thought to mainly act in brain to remodel the extracellular matrix, the family of metalloproteinases is important in many normal and pathological processes in the nervous system. Matrix metalloproteinases (MMPs) and A disintegrin and metalloproteinases (ADAMs) are the two major families of metalloproteinases in the brain. MMPs are comprised of several related enzymes that act on extracellular molecules. Normally, they are important in angiogenesis and neurogenesis in development. In neuroinflammatory illnesses, they disrupt the basal lamina and tight junction proteins to open the blood-brain barrier (BBB). ADAMs are important in neuroinflammation through activation of tumor necrosis factor-α (TNF-α) and their action as secretases that modulate the action of receptors on the cell surface. Four tissue inhibitors of metalloproteinases (TIMPs) are the main inhibitors of the MMPs and ADAMs. Recently, MMPs were found to affect DNA repair processes by an unexpected intranuclear action. MMPs and ADAMs have been implicated in the pathophysiology of neurodegenerative diseases such as Alzheimer's disease and vascular cognitive impairment. Growing literature on the functions of MMPs and ADAMs in the central nervous system is opening up new and exciting areas of research that may lead to novel approaches to treatment of neurological diseases.

Matrix metalloproteinases and neurotrauma: evolving roles in injury and reparative processes

Matrix metalloproteinases (MMPs) are involved in a wide range of proteolytic events in fetal development and normal tissue remodeling as well as wound healing and inflammation. In the CNS, they have been implicated in a variety of neurodegenerative diseases ranging from multiple sclerosis to Alzheimer disease and are integral to stroke-related cell damage. Although studies implicate increased activity of MMPs in pathogenesis in the CNS, there is also a growing literature to support their participation in events that support recovery processes. Here the authors provide a brief overview of MMPs and their regulation, address their complex roles following traumatic injuries to the adult and developing CNS, and consider their time- and context-dependent signatures that influence both injury and reparative processes.

Hemoglobin-induced oxidative stress contributes to matrix metalloproteinase activation and blood-brain barrier dysfunction in vivo

Hemoglobin (Hb) released from extravasated erythrocytes is implicated in brain edema after intracerebral hemorrhage (ICH). Hemoglobin is a major component of blood and a potent mediator of oxidative stress after ICH. Oxidative stress and matrix metalloproteinases (MMPs) are associated with blood-brain barrier (BBB) dysfunction. This study was designed to elucidate whether Hb-induced oxidative stress contributes to MMP-9 activation and BBB dysfunction in vivo. An intracerebral injection of Hb into rat striata induced increased hydroethidine (HEt) signals in parallel with MMP-9 levels. In situ gelatinolytic activity colocalized with oxidized HEt signals in vessel walls, accompanied by immunoglobulin G leakage and a decrease in immunoactivity of endothelial barrier antigen, a marker of endothelial integrity. Administration of a nonselective MMP inhibitor prevented MMP-9 levels and albumin leakage in injured striata. Moreover, reduction in oxidative stress by copper/zinc-superoxide dismutase (SOD1) overexpression reduced oxidative stress, MMP-9 levels, albumin leakage, and subsequent apoptosis compared with wild-type littermates. We speculate that Hb-induced oxidative stress may contribute to early BBB dysfunction and subsequent apoptosis, partly through MMP activation, and that SOD1 overexpression may reduce Hb-induced oxidative stress, BBB dysfunction, and apoptotic cell death.

Metalloproteinase and stroke infarct size: role for anti-inflammatory treatment?

Deregulation of matrix metalloproteinases (MMPs), the largest class of human proteases, has been implicated in brain damage in both animal and human studies. Some MMPs are elevated after stroke (both in plasma and in brain tissue), and their expression is enhanced by t-PA during thrombolysis related to hemorrhagic transformation events. Although the exact cellular source of MMPs remains unknown, brain endothelium, astrocytes, neurons, and inflammatory-activated cells, such as neutrophils, may release MMP-2, MMP-3, MMP-8, MMP-9, MMP-10, and/or MMP-13. Neurovascular perturbations occurring after stroke lead to blood-brain barrier leakage, edema, hemorrhage, leukocyte infiltration, and progressive inflammatory reactions to brain injury over hours or even days after the initial stroke. Synthesized MMP inhibitors and several compounds used for stroke secondary prevention, such as anti-inflammatory drugs, might decrease MMPs and improve the acute treatment of human brain ischemia without compromising the beneficial effects of matrix plasticity during stroke recovery.

Type IV collagen induces expression of thrombospondin-1 that is mediated by integrin alpha1beta1 in astrocytes

Following brain injury, thrombospondin-1 (TSP-1) is involved in angiogenesis and synaptic recovery. In this study, we used a cold injury-model and found that TSP-1 mRNA was markedly upregulated after brain injury. Immunohistochemistry showed that TSP-1 was upregulated in both the core of the lesion and in the perilesional area of injured brain tissue. Numerous astrocytes immunopositive for glial fibrillary acidic protein (GFAP) were found in the perilesional area, and TSP-1 was also expressed in almost all astrocytes surrounding blood vessels at 4 days after injury. Next, we examined the influence of vascular basement membrane components on TSP-1 expression. When astrocytes were cultured on type IV collagen, TSP-1 was significantly upregulated compared with the expression when cells were grown on laminin, fibronectin, or poly-L-lysine. This increase occurred exclusively when astrocytes were grown on the native form of type IV collagen but not on the heat-denatured form or the non-collagenous 1 domain. Further, integrin alpha1 and beta1 mRNAs were upregulated concomitantly with GFAP mRNA, and integrin alpha1 protein was localized to the endfeet of astrocytes that surrounded blood vessels in the injured brain. Using function-blocking antibodies, we found that the effect of type IV collagen was attributed to integrin alpha1beta1 in primary astrocytes. Collectively, our results suggest that vascular basement membrane components substantially impact gene expression in astrocytes during brain tissue repair.

Critical role for copper/zinc-superoxide dismutase in preventing spontaneous intracerebral hemorrhage during acute and chronic hypertension in mice

BACKGROUNDS AND PURPOSE

Superoxide is associated with spontaneous intracerebral hemorrhage (ICH) during hypertension. The goal of this study was to test the hypothesis that changes in superoxide, in genetically altered mice with deletion and overexpression of copper/zinc-superoxide dismutase (SOD1), modulate susceptibility to ICH.

METHODS

Chronic hypertension was produced by infusion of angiotensin II and an inhibitor of nitric oxide synthase in drinking water in SOD1 transgenic (SOD1Tg) mice, SOD1-deficient (SOD1(-/-)) mice, and their respective wild-type littermates. Acute hypertension was produced by daily injections of angiotensin II in some mice with chronic hypertension to produce ICH. We evaluated susceptibility to ICH, oxidative stress (superoxide, NAD[P]H oxidase activity, SOD activity), gene expression, and activity of matrix metalloproteinases.

RESULTS

Incidence, size, and number of ICHs were reduced in SOD1Tg mice and were increased in SOD1(-/-) mice compared with their wild-type littermates. Levels of superoxide increased in the brain even before developing ICH in wild-type littermates, whereas levels of superoxide remained low in SOD1Tg mice. Changes in level of matrix metalloproteinase-9 paralleled oxidative stress in SOD1Tg mice and wild-type littermates. Moreover, levels of superoxide and matrix metalloproteinase-9 were greater in SOD1(-/-) mice than wild-type littermates after induction of ICH. Active matrix metalloproteinases colocalized on cerebral vessels that appeared to lead toward regions with ICH.

CONCLUSIONS

These results suggest that superoxide contributes to the pathogenesis of spontaneous ICH, possibly through activation of matrix metalloproteinase-9, and that SOD1 protects against spontaneous ICH during hypertension.

Elevation of matrix metalloproteinases 3 and 9 in cerebrospinal fluid and blood in patients with severe traumatic brain injury

OBJECTIVE

Traumatic brain injury (TBI) causes an increase in matrix metalloproteinases (MMPs), which are associated with neuroinflammation, blood-brain barrier disruption, hemorrhage, and cell death. We hypothesized that patients with TBI have an increase in MMPs in ventricular cerebrospinal fluid (CSF) and plasma.

METHODS

Patients with TBI and a ventricular catheter were entered into the study. Samples of CSF and plasma were collected at the time of catheter placement and at 24 and 72 hours after admission. Seven TBI patients were entered into the study, with 6 having complete data for analysis. Only patients who had a known time of insult that fell within a 6-hour window from initial insult to ventriculostomy were accepted into the study. Control CSF came from ventricular fluid in patients undergoing shunt placement for normal pressure hydrocephalus. Both MMP-2 and MMP-9 were measured with gelatin zymography and MMP-3 with Western immunoblot.

RESULTS

We found a significant elevation in the levels of the latent form of MMP-9 (92-kD) in the CSF obtained at the time of arrival (P < 0.05). Elevated levels of MMP-2 were detected in plasma at 72 hours, but not in the CSF. Using albumin from both CSF and blood, we calculated the MMP-9 index, which was significantly increased in the CSF, indicating endogenous MMP production. Western immunoblot showed elevated levels of MMP-3 in CSF at all times measured, whereas MMP-3 was not detected in the CSF of normal pressure hydrocephalus.

CONCLUSION

We show that MMPs are increased in the CSF of TBI patients. Although the number of patients was small, the results were robust and clearly demonstrated increases in MMP-3 and MMP-9 in ventricular CSF in TBI patients compared with controls. Although these preliminary results will need to be replicated, we propose that MMPs may be important in blood-brain barrier opening and hemorrhage secondary to brain injury in patients.

Cyclooxygenase-2 is upregulated in copper-deficient rats

Copper deficiency inactivates Cu/Zn-SOD and promotes accumulation of reactive oxygen species. This process likely impairs nitric oxide (NO)-mediated relaxation as well as triggers vascular inflammation. The current study was designed to determine whether COX-2, a proinflammatory protein, expression and activity are upregulated in the oxidative environment associated with inadequate Cu. Weanling male Sprague Dawley rats were fed purified diets which were either Cu-adequate (Cu-A); Cu-marginal (Cu-M), Cu-deficient (Cu-D), or the Cu-D diet combined with the SOD mimetic Tempol (Cu-D/T; 1 mM in drinking water) for 4 weeks. COX-2 protein, PGE(2) (COX-2 metabolite) and isoprostanes (index of oxidative stress) were all higher in the Cu-D group vs Cu-A group, but no significant differences occurred between the Cu-M and Cu-A groups. Tempol protected against an attenuation of NO-mediated vasodilation in the Cu-D rats but did not prevent the elevation of PGE(2) or isoprostanes. Our data suggest a role for copper as a modulator of oxidative stress and inflammation independent of SOD activity or NO-derived oxidants.

Induction of mmp-9 expression and endothelial injury by oxidative stress after spinal cord injury

Matrix metalloproteinase-9 (MMP-9) activation plays an important role in blood-brain barrier (BBB) dysfunction after central nervous system injury. Oxidative stress is also implicated in the pathogenesis after cerebral ischemia and spinal cord injury (SCI), but the relationship between MMP-9 activation and oxidative stress after SCI has not yet been clarified. We examined MMP-9 expression after SCI using copper/zinc-superoxide dismutase (SOD1) transgenic (Tg) rats. Our results show that MMP-9 activity significantly increased after SCI in both SOD1 Tg rats and their wild-type (Wt) littermates, although the increase was less in the SOD1 Tg rats. This pattern of MMP-9 expression was further confirmed by immunostaining and Western blot analysis. In situ zymography showed that gelatinolytic activity increased after SCI in the Wt rats, while the increase was less in the Tg rats. Evans blue extravasation increased in both the Wt and Tg rats, but was less in the SOD1 Tg rats. Inhibitor studies showed that, with an intrathecal injection of SB-3CT (a selective MMP-2/MMP-9 inhibitor), the MMP activity, Evans blue extravasation, and apoptotic cell death decreased after SCI. We conclude that increased oxidative stress after SCI leads to MMP-9 upregulation, BBB disruption, and apoptosis, and that overexpression of SOD1 in Tg rats decreases oxidative stress and further attenuates MMP-9 mediated BBB disruption.

Diverse roles of matrix metalloproteinases and tissue inhibitors of metalloproteinases in neuroinflammation and cerebral ischemia

Regulation of the extracellular matrix by proteases and protease inhibitors is a fundamental biological process for normal growth, development and repair in the CNS. Matrix metalloproteinases (MMPs) and the tissue inhibitors of metalloproteinases (TIMPs) are the major extracellular-degrading enzymes. Two other enzyme families, a disintegrin and metalloproteinase (ADAM), and the serine proteases, plasminogen/plasminogen activator (P/PA) system, are also involved in extracellular matrix degradation. Normally, the highly integrated action of these enzyme families remodels all of the components of the matrix and performs essential functions at the cell surface involved in signaling, cell survival, and cell death. During the inflammatory response induced in infection, autoimmune reactions and hypoxia/ischemia, abnormal expression and activation of these proteases lead to breakdown of the extracellular matrix, resulting in the opening of the blood-brain barrier (BBB), preventing normal cell signaling, and eventually leading to cell death. There are several key MMPs and ADAMs that have been implicated in neuroinflammation: gelatinases A and B (MMP-2 and -9), stromelysin-1 (MMP-3), membrane-type MMP (MT1-MMP or MMP-14), and tumor necrosis factor-alpha converting enzyme (TACE). In addition, TIMP-3, which is bound to the cell surface, promotes cell death and impedes angiogenesis. Inhibitors of metalloproteinases are available, but balancing the beneficial and detrimental effects of these agents remains a challenge.

Moderate and severe traumatic brain injury induce early overexpression of systemic and brain gelatinases

OBJECTIVE

Recent experimental evidence suggests that matrix metalloproteinases (MMPs) are implicated in the pathophysiology of traumatic brain injury (TBI) by increasing blood-brain barrier permeability and exacerbating posttraumatic edema. We examined the acute profile of MMP-2 and MMP-9 in the plasma of patients with moderate or severe TBI and in the brain extracellular fluid (ECF).

DESIGN

Prospective observational study.

SETTING

Neurotraumatology intensive care unit of a tertiary university hospital.

PATIENTS

Twenty patients with moderate or severe TBI were included and three groups were used as controls: 20 patients with a mild head injury and normal CT scan, 15 moderate polytrauma patients without TBI, and 20 healthy volunteers.

INTERVENTIONS

Plasma samples were collected within the first 12[Symbol: see text]h and at 24[Symbol: see text]h post-injury. Simultaneous brain microdialysate and plasma samples were obtained in four moderate-severe TBI patients at additional timepoints: 48, 72, and 96[Symbol: see text]h post-TBI.

MEASUREMENTS AND MAIN RESULTS

Gelatinases (MMP-2 and MMP-9) were measured by gelatin zymography. A significant increase in plasma gelatinases was observed at baseline when compared with healthy volunteers in the study group. This early increase was followed by a significant decrease at 24[Symbol: see text]h post-injury. Brain microdialysis samples presented a similar time profile as plasma samples for both gelatinases.

CONCLUSIONS

High levels of gelatinases were found in plasma and brain ECF in the early phase of TBI, indicating that both local and systemic trauma-induced upregulation of gelatinases in the acute phase might play an important role in the pathophysiology of TBI and could be a future therapeutic target.

Brain contusions induce a strong local overexpression of MMP-9. Results of a pilot study

BACKGROUND

Brain contusions are inflammatory evolutive lesions that induce intracranial pressure increase and edema, contributing to neurological outcome. Matrix metalloproteinases (MMPs) 2 and 9 can degrade the majority of the extracellular matrix components, and are implicated in blood-brain barrier disruption and edema formation. The aim of this study was to investigate MMP-2 and MMP-9 profiles in human brain contusions using zymography.

METHODS

A prospective study was conducted in 20 traumatic brain injury patients where contusion brain tissue was resected. Brain tissues from lobectomies were used as controls. Brain homogenates were analysed by gelatin zymography and in situ zimography was performed to confirm results, on one control and one brain contusion tissue sample.

FINDINGS

MMP-2 and MMP-9 levels were higher in brain contusions when compared to controls. MMP-9 was high during the first 24 hours and at 48 to 96 hours, whereas MMP-2 was slightly high at 24 to 96 hours. In situ zymography confirmed gelatin zymography results. A relation between outcome and MMP-9 levels was found; MMP-9 levels were higher in patients with worst outcome.

CONCLUSIONS

Our results indicate strong time-dependent gelatinase expression primarily from MMP-9, suggesting that the inflammatory response induced by focal lesions should be considered as a new therapeutic target.

Matrix metalloproteinase-9 inhibition attenuates vascular endothelial growth factor-induced intracerebral hemorrhage

BACKGROUND AND PURPOSE

Human brain arteriovenous malformation tissue displays increased levels of vascular endothelial growth factor (VEGF) as well as matrix metalloproteinase (MMP)-9, a tissue protease associated with various intracerebral hemorrhage (ICH). We hypothesized that increased MMP-9 was associated with ICH induced by vascular endothelial growth factor hyperstimulation and that this effect could be attenuated by nonspecific MMP inhibition.

METHODS

We used a mouse model with adenoviral vector-mediated vascular endothelial growth factor transduction in the brain. The association of MMP-9 expression and the brain tissue hemoglobin levels, an index of ICH, after stereotactic injection of adenoviral vector-mediated vascular endothelial growth factor into caudate putamen was assessed. A dose-response study with adenoviral vector-mediated vascular endothelial growth factor and a time course study at both 24 and 48 hours postinjection were performed. Effects of minocycline, a nonspecific MMP inhibitor, and pyrrolidine dithiocarbamate, an upstream regulator of MMPs, on MMP-9 activity and thereby the degree of ICH were also tested.

RESULTS

Adenoviral vector-mediated vascular endothelial growth factor at the higher dose and at 48 hours induced MMP-9 levels 6-fold (n=6, P=0.02) and increased brain tissue hemoglobin (43.4+/-11.5 versus 30.3+/-4.1 mug/mg, n=6, P=0.003) compared with the adenoviral vector control. Immnunostaining was positive for MMP-9 around the cerebral vessels and the hemorrhagic areas. Minocycline and pyrrolidine dithiocarbamate administration suppressed vascular endothelial growth factor-induced MMP-9 activity (n=6, P=0.003 and P=0.01, respectively) and the associated increases in hemoglobin levels (n=5-6, P=0.001 and P=0.02, respectively).

CONCLUSIONS

Vascular endothelial growth factor-induced ICH is associated with increased MMP-9 expression. Suppression of MMP-9 by minocycline or pyrrolidine dithiocarbamate attenuated ICH, suggesting the therapeutic potential of MMP inhibitors in cerebral vascular rupture.

Expression of matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinase (TIMP) in cerebral cavernous malformations: immunohistochemical analysis of MMP-2, -9 and TIMP-2

OBJECT

Hemorrhage from cerebral vascular malformations such as cerebral cavernous malformation (CCM) can result in significant mortality and morbidity, but its underlying mechanism is undetermined. Excessive degradation of the vascular matrix by matrix metalloproteinases (MMPs), proteolytic enzymes that degrade all the components of extracellular matrix, can lead to instability of the vascular structure and can thereby cause bleeding. Thus we examined the expression of MMPs and tissue inhibitors of metalloproteinase (TIMP) in CCM.

PATIENTS AND METHODS

We performed immunohistochemistry for MMP-2, -9, and TIMP-2 using Paraffin-embedded sections of the surgical specimens obtained from seven patients with CCM. All patients had a history of hemorrhage from CCM.

FINDINGS

In all patients (7/7, 100%), MMP-2 and -9 were strongly expressed in endothelial cells of CCMs. Endothelial expression of TIMP-2 was also evident in all seven patients. In contrast, MMP-2, -9 and TIMP-2 were not identified in adjacent normal brain tissue.

CONCLUSION

We found that CCM showed the increased endothelial expression of MMP-2, -9, and TIMP-2. Endothelial expression of MMPs and/or TIMP may affect the vascular matrix stability, and thus can contribute to hemorrhage from CCM.

The role of matrix metalloproteinases in infant traumatic brain injury

Matrix metalloproteinases (MMPs) play an essential role in tissue repair, cell death and morphogenesis and may constitute therapeutic targets for acute brain injuries. In this study, we investigated the expression of 72 kDa and 92 kDa collagenases MMP-2 and MMP-9 at transcriptional, functional and protein expression level following traumatic brain injury in infant rats. Seven-day-old Wistar rats were subjected to head trauma using a weight drop device. Pups were sacrificed at defined time points (2-72 h) after trauma and brains were processed for molecular studies (semiquantitative and real-time PCR, Western blot, gelatin zymography) and histology. Trauma triggered widespread cell death in the cortex, basal ganglia and white matter. mRNA levels for MMP-2 and -9 were increased in the brain at 12-72 h after trauma. Protein expression of the analyzed MMPs and activity of MMP-2 were increased at 12 h and peaked at 24 h after trauma. Intraperitoneal injection of GM6001 (Ilomastat), an MMP inhibitor, 2 h after trauma, substantially attenuated traumatic brain injury in a dose-dependent manner. These findings causally link the MMPs to trauma-induced neuronal cell death in the immature rodent brain. MMPs might serve as useful targets for therapeutic approaches aimed at preserving neuronal function in the immature brain in the context of mechanical injury.

Mouse brains deficient in neuronal PDGF receptor-beta develop normally but are vulnerable to injury

Platelet-derived growth factors (PDGFs) and PDGF receptors (PDGFRs) are widely expressed in the mammalian CNS, though their functional significance remains unclear. The corresponding null-knockout mutations are lethal. Here, we developed novel mutant mice in which the gene encoding the beta subunit of PDGFR (PDGFR-beta) was genetically deleted in CNS neurons to elucidate the role of PDGFR-beta, particularly in the post-natal stage. Our mutant mice reached adulthood without apparent anatomical defects. In the mutant brain, immunohistochemical analyses showed that PDGFR-beta detected in neurons and in the cells in the subventricular zone of the lateral ventricle in wild-type mice was depleted, but PDGFR-beta detected in blood vessels remained unaffected. The cerebral damage after cryogenic injury was severely exacerbated in the mutants compared with controls. Furthermore, TdT-mediated dUTP-biotin nick end labeling (TUNEL)-positive neuronal cell death and lesion formation in the cerebral hemisphere were extensively exacerbated in our mutant mice after direct injection of NMDA without altered NMDA receptor expression. Our results clearly demonstrate that PDGFR-beta expressed in neurons protects them from cryogenic injury and NMDA-induced excitotoxicity.

Elevation of hippocampal MMP-3 expression and activity during trauma-induced synaptogenesis

The matrix metalloproteinase (MMP) enzyme family contributes to the regulation of a variety of brain extracellular matrix molecules. In order to assess their role in synaptic plasticity following traumatic brain injury (TBI), we compared expression of stromelysin-1 (MMP-3) protein and mRNA in two rodent models of TBI exhibiting different levels of recovery: adaptive synaptic plasticity following central fluid percussion injury and maladaptive synaptic plasticity generated by combined TBI and bilateral entorhinal cortical lesion (TBI + BEC). We sampled the hippocampus at 7 days postinjury, targeting a selectively vulnerable brain region and a survival interval exhibiting rapid synaptogenesis. We report elevated expression of hippocampal MMP-3 mRNA and protein after TBI. MMP-3 immunohistochemical staining showed increased protein levels relative to sham-injured controls, primarily localized to cell bodies within the deafferented dendritic laminae. Injury-related differences in MMP-3 protein were also observed. TBI alone elevated MMP-3 immunobinding over the stratum lacunosum moleculare (SLM), inner molecular layer and hilus, while TBI + BEC generated more robust increases in MMP-3 reactivity within the deafferented SLM and dentate molecular layer (DML). Double labeling with GFAP confirmed the presence of MMP-3 within reactive astrocytes induced by each injury model. Semi-quantitative RT-PCR revealed that MMP-3 mRNA also increased after each injury, however, the combined insult induced a much greater elevation than fluid percussion alone: 1.9-fold vs. 79%, respectively. In the TBI + BEC model, MMP-3 up-regulation was spatio-temporally correlated with increased enzyme activity, an effect which was attenuated with the neuroprotective compound MK-801. These results show that distinct pathological conditions elicited by TBI can differentially affect MMP-3 expression during reactive synaptic plasticity. Notably, these effects are both transcriptional and translational and are correlated with functionally active enzyme.

Increased Matrix Metalloproteinase-9 in Blood in Association with Activation of Interleukin-6 after Traumatic Brain Injury: Influence of Hypothermic Therapy

Recent experimental data have shown that levels of matrix metalloproteinase-9 (MMP-9) increase after traumatic brain injury (TBI), degrading components of the basal lamina disrupting the blood-brain barrier. However, the post-traumatic secretion patterns of MMP-9 in humans are unknown. We measured the concentration of MMP-9 in plasma after TBI at the same time as the concentration of interleukin-6 (IL-6) in serum. Levels of MMP-9 and IL-6 in systemic arterial and jugular venous blood from seven patients with TBI were measured on days 0 and 1 post-injury. All patients underwent hypothermia at 32-35 degrees C as soon as possible after admission. Before induction of hypothermia, levels of MMP-9 in arterial and internal jugular venous blood exceeded the normal range. Higher MMP-9 levels were detected in internal jugular venous blood than in arterial blood. After hypothermia had been induced, MMP-9 levels in arterial blood and internal jugular venous blood decreased significantly, to within the normal range. In addition to these changes, a significant correlation was seen between levels of MMP-9 and IL-6 in internal jugular venous blood during the investigation period. These results indicate that MMP-9 is elevated in patients with acute TBI, and may play an important role in traumatic brain damage. The elevation of MMP-9 is associated with inflammatory events following TBI. Hypothermic intervention may suppress the elevation of MMP-9 with suppression of the inflammatory response, affording neuroprotection in TBI.

Elevated levels of matrix metalloproteinases-9 and -1 and of tissue inhibitors of MMPs, TIMP-1 and TIMP-2 in postmortem brain tissue of progressive supranuclear palsy

We determined the levels and tissue localization of matrix metalloproteinases (MMPs) as well as their endogenous tissue inhibitors (TIMPs) in postmortem brain tissue from 13 patients with progressive supranuclear palsy (PSP) and 8 age-matched controls. MMP-9 expression was significantly increased in both the frontal cortex (p = 0.002) and substantia nigra (p = 0.003) of PSP cases as compared to controls whereas MMP-1 levels were increased in the substantia nigra (p = 0.01) but unchanged in the frontal cortex (p = 0.41). Levels of the endogenous tissue inhibitors of MMPs, TIMP-1 and TIMP-2 were significantly elevated in the substantia nigra (TIMP-1: p = 0.004, TIMP-2: p = 0.01). Levels of TIMPs were unchanged in PSP frontal cortex as compared to control cases. Together, these data show alterations of MMPs and TIMPs in the substantia nigra as well as in the frontal cortex of PSP, consistent with the possibility that alterations in MMPs/TIMPs may contribute to disease pathogenesis.

Treatment of cold injury-induced brain edema with a nonspecific matrix metalloproteinase inhibitor MMI270 in rats

Blood-brain barrier (BBB) disruption is a critical event leading to vasogenic brain edema and secondary brain damage after cold injury-induced brain trauma. Matrix metalloproteinases (MMPs) are implicated in BBB disruption in this model. The purpose of this study was to examine the effects of MMI270, a synthetic nonspecific MMP inhibitor, on cold injury-induced brain edema in rats. Treatment with MMI270, a bolus injection at a dose of 30 mg/kg, was started immediately after the induction of cold injury and was continued at a dose of 40 mg/kg/day using an intraperitoneal osmotic minipump. At 24 hours after the cold injury, the brain water content and the BBB permeability to Evans Blue (EB) were determined. The secondary brain lesion was assessed using hematoxylin and eosin (H-E) staining at 7 days after the cold injury. Compared with the untreated control group, treatment with MMI270 significantly reduced the brain water content in the ipsilateral core and intermediate areas and protected the BBB integrity to EB in the ipsilateral core area. The secondary lesion was significantly smaller in the MMI270-treated animals compared with the untreated animals. Our results indicate that treatment with MMI270 in rats exhibits protection in acute brain edema formation and secondary brain lesion by attenuating the BBB permeability after cold injury.