minocycline and Stroke

Various randomized-controlled clinical trials (RCTs) have investigated the neuroprotective role of minocycline in acute ischemic stroke (AIS) or acute intracerebral hemorrhage (ICH) patients. We sought to consolidate and investigate the efficacy and safety of minocycline in patients with acute stroke.. Literature search spanned through November 30, 2017 across major databases to identify all RCTs that reported following efficacy outcomes among acute stroke patients treated with minocycline vs. placebo: National Institute of Health Stroke Scale (NIHSS), Barthel Index (BI), and modified Rankin Scale (mRS) scores. Additional safety, neuroimaging and biochemical endpoints were extracted. We pooled mean differences (MD) and risk ratios (RR) from RCTs using random-effects models.. We identified 7 RCTs comprising a total of 426 patients. Of these, additional unpublished data was obtained on contacting corresponding authors of 5 RCTs. In pooled analysis, minocycline demonstrated a favorable trend towards 3-month functional independence (mRS-scores of 0-2) (RR = 1.31; 95% CI 0.98-1.74, p = 0.06) and 3-month BI (MD = 6.92; 95% CI - 0.92, 14.75; p = 0.08). In AIS subgroup, minocycline was associated with higher rates of 3-month mRS-scores of 0-2 (RR = 1.59; 95% CI 1.19-2.12, p = 0.002; I. Although data is limited, minocycline demonstrated efficacy and seems a promising neuroprotective agent in acute stroke patients, especially in AIS subgroup. Further RCTs are needed to evaluate the efficacy and safety of minocycline among ICH patients.

Topics: Brain Ischemia; Cerebral Hemorrhage; Humans; Minocycline; Neuroprotective Agents; Randomized Controlled Trials as Topic; Stroke

Accumulating research substantiates the statement that inflammation plays an important role in the development of stroke. Both proinflammatory and anti-inflammatory mediators are involved in the pathogenesis of stroke, an imbalance of which leads to inflammation. Anti-inflammation is a kind of hopeful strategy for the prevention and treatment of stroke. Substantial studies have demonstrated that minocycline, a second-generation semisynthetic antibiotic belonging to the tetracycline family, can inhibit neuroinflammation, inflammatory mediators and microglia activation, and improve neurological outcome. Experimental and clinical data have found the preclinical and clinical potential of minocycline in the treatment of stroke due to its anti-inflammation properties and anti-inflammation-induced pathogeneses, including antioxidative stress, antiapoptosis, inhibiting leukocyte migration and microglial activation, and decreasing matrix metalloproteinases activity. Hence, it suggests a great future for minocycline in the therapeutics of stroke that diminish the inflammatory progress of stroke.

Topics: Animals; Anti-Bacterial Agents; Humans; Inflammation; Minocycline; Stroke

Minocycline, in animal models and 2 small randomized controlled human trials, is a promising neuroprotective agent in acute stroke. We analyzed the efficacy and safety of intravenous minocycline in acute ischemic and hemorrhagic stroke.. A multicenter prospective randomized open-label blinded end point evaluation pilot study of minocycline 100 mg administered intravenously, commenced within 24 hours of onset of stroke, and continued 12 hourly for a total of 5 doses, versus no minocycline. All participants received routine stroke care. Primary end point was survival free of handicap (modified Rankin Scale, ≤2) at day 90.. Ninety-five participants were randomized; 47 to minocycline and 48 to no minocycline. In the intention-to-treat population, 29 of 47 (65.9%) allocated minocycline survived free of handicap compared with 33 of 48 (70.2%) allocated no minocycline (rate ratio, 0.94; 95% confidence interval, 0.71-1.25 and odds ratio, 0.73; 95% CI, 0.31-1.71). A meta-analysis of the 3 human trials suggests minocycline may increase the odds of handicap-free survival by 3-fold (odds ratio, 2.99; 95% CI, 1.74-5.16) but there was substantial heterogeneity among the trials.. In this pilot study of a small sample of acute stroke patients, intravenous minocycline was safe but not efficacious. The study was not powered to identify reliably or exclude a modest but clinically important treatment effect of minocycline. Larger trials would improve the precision of the estimates of any treatment effect of minocycline.. http://www.anzctr.org.au. Unique identifier: ACTRN12612000237886.

Topics: Administration, Intravenous; Aged; Aged, 80 and over; Anti-Bacterial Agents; Brain Ischemia; Cerebral Hemorrhage; Female; Humans; Male; Middle Aged; Minocycline; Pilot Projects; Severity of Illness Index; Stroke; Treatment Outcome

Stroke is a devastating disease associated with high morbidity and mortality. Despite the approved indication of systemic thrombolytic therapy in the United States for the acute management of ischemic stroke, its use is limited given a strict eligibility criteria and a risk for hemorrhagic transformation as a feared adverse effect. Many agents have been studied without success for neuroprotection in patients with stroke to reduce vascular injury and improve long-term functional outcomes. Minocycline is a tetracycline antibiotic that shows promise for its neuroprotective effects in multiple animal models and three human trials. It affects multiple pathways to reduce apoptosis, neuroinflammation, infarct size, and vascular injury. The aim of this review is to discuss current evidence for minocycline from pre-clinical and early clinical trials and its potential role in neuroprotection in patients with acute ischemic stroke.

Topics: Animals; Anti-Bacterial Agents; Drug Repositioning; Humans; Minocycline; Neuroprotective Agents; Stroke

Neuroprotection seeks to restrict injury to the brain parenchyma following an ischaemic insult by preventing salvageable neurons from dying. The concept of neuroprotection has shown promise in experimental studies, but has failed to translate into clinical success. Many reasons exist for this including the heterogeneity of human stroke and the lack of methodological agreement between preclinical and clinical studies. Even with the proposed Stroke Therapy Academic Industry Roundtable criteria for preclinical development of neuroprotective agents for stroke, we have still seen limited success in the clinic, an example being NXY-059, which fulfilled nearly all the Stroke Therapy Academic Industry Roundtable criteria. There are currently a number of ongoing trials for neuroprotective strategies including hypothermia and albumin, but the outcome of these approaches remains to be seen. Combination therapies with thrombolysis also need to be fully investigated, as restoration of oxygen and glucose will always be the best therapy to protect against cell death from stroke. There are also a number of promising neuroprotectants in preclinical development including haematopoietic growth factors, and inhibitors of the nicotinamide adenine dinucleotide phosphate oxidases, a source of free radical production which is a key step in the pathophysiology of acute ischaemic stroke. For these neuroprotectants to succeed, essential quality standards need to be adhered to; however, these must remain realistic as the evidence that standardization of procedures improves translational success remains absent for stroke.

Topics: Acute Disease; Animals; Benzenesulfonates; Brain Ischemia; Chelating Agents; Clinical Trials as Topic; Combined Modality Therapy; Diffusion of Innovation; Disease Models, Animal; Drug Evaluation, Preclinical; Egtazic Acid; Hematopoietic Cell Growth Factors; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Hypothermia, Induced; Magnesium; Minocycline; NADPH Oxidases; Neuroprotective Agents; Pregnatrienes; Serum Albumin; Stroke; Thrombolytic Therapy; Translational Research, Biomedical

Tissue plasminogen activator (tPA) administered within 4.5h of symptom onset restores cerebral blood flow (CBF) and promotes neurological recovery of stroke patients. However, the narrow therapeutic time window and the risk of intracerebral hemorrhage after tPA treatment pose major hurdles to its clinical usage. In light of the failures of neuroprotective therapies in clinical trials, emerging concepts suggest that neuroprotection alone without restoration of tissue perfusion and vascular integrity may not be adequate for treatment of acute stroke. Here we review evidence of the use of adjuvant pharmacological agents to extend the therapeutic window for tPA via targeting the neurovascular unit and the underlying mechanisms of the combination therapy in experimental stroke.

Topics: Anti-Bacterial Agents; Antineoplastic Agents; Boronic Acids; Bortezomib; Cerebral Hemorrhage; Drug Therapy, Combination; Erythropoietin; Fibrinolytic Agents; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Minocycline; Pyrazines; Stroke; Tissue Plasminogen Activator

There is some evidence that in animal models of acute ischaemic stroke, combinations of neuroprotective agents might be more efficacious than the same agents administered alone. Hence, we developed pragmatic, empirical criteria based on therapeutic target, cost, availability, efficacy, administration, and safety to select drugs for testing in combination in animal models of acute stroke. Magnesium sulphate, melatonin, and minocycline were chosen from a library of neuroprotective agents, and were tested in a more 'realistic' model favoured by the STAIR (Stroke Therapy Academic Industry Roundtable). Outcome was assessed with infarct volume, neurologic score, and two newly developed scales measuring general health and physiologic homeostasis. Owing to the failure to achieve neuroprotection in aged, hypertensive animals with drug delivery at 3 hours, the bar was lowered in successive experiments to determine whether neuroprotection could be achieved under conditions more conducive to recovery. Testing in younger animals showed more favourable homeostasis and general health scores than did testing in older animals, but infarct volume and neurologic scores did not differ with age, and treatment efficacy was again not shown. Testing with shorter occlusions resulted in smaller infarct volumes; nevertheless, treatment efficacy was still not observed. It was concluded that this combination, in these stroke models, was not effective.

Topics: Age Factors; Animals; Drug Evaluation, Preclinical; Drug Interactions; Drug Therapy, Combination; Magnesium Sulfate; Melatonin; Minocycline; Neuroprotective Agents; Rats; Severity of Illness Index; Stroke; Treatment Outcome

There is only 1 US Food and Drug Administration-approved drug for acute ischemic stroke: tissue plasminogen activator (tPA). Due to a short time window and fear of intracerebral hemorrhage (ICH), tPA remains underutilized. There is great interest in developing combination drugs to use with tPA to improve the odds of a favorable recovery and to reduce the risk of ICH. Minocycline is a broad-spectrum antibiotic that has been found to be a neuroprotective agent in preclinical ischemic stroke models. Minocycline inhibits matrix metalloproteinase-9, a biomarker for ICH associated with tPA use. Minocycline is also an anti-inflammatory agent and inhibits poly (ADP-ribose) polymerase-1. Minocycline has been safe and well tolerated in the clinical trials conducted to date.

Topics: Animals; Brain; Clinical Trials as Topic; Drug Discovery; Gene Expression Regulation, Enzymologic; Humans; Matrix Metalloproteinase 9; Minocycline; Plasminogen Activators; Stroke

Tissue plasminogen activator (tPA) is the only drug approved by the United States Food and Drug Administration for treatment of acute ischemic stroke. Because the drug must be used soon after symptom onset and is associated with intracerebral hemorrhage, tPA remains underutilized. Research has therefore focused on identifying other drugs that can be used concomitantly with tPA to improve the odds of a favorable recovery and to reduce the risk of intracerebral hemorrhage. Minocycline is a broad-spectrum antibiotic that has been found to be a neuroprotective agent in preclinical ischemic stroke models. Minocycline inhibits matrix metalloproteinase-9, a biomarker for intracerebral hemorrhage associated with tPA use. Minocycline is also an antiinflammatory agent and inhibits poly(ADP-ribose) polymerase-1. Minocycline has been safe and well tolerated in clinical trials. Additional safety and efficacy data are needed, and a phase III trial of minocycline with tPA in patients experiencing acute ischemic stroke is planned.

Topics: Animals; Brain Ischemia; Drug Repositioning; Female; Fibrinolytic Agents; Humans; Male; Matrix Metalloproteinase 9; Mice; Minocycline; Neuroprotective Agents; Rats; Stroke; Time Factors; Tissue Plasminogen Activator

Minocycline is a widely used tetracycline antibiotic. For decades, it has been used to treat various gram-positive and gram-negative infections. Minocycline was recently shown to have neuroprotective properties in animal models of acute neurologic injury. As a neuroprotective agent, the drug appears more effective than other treatment options. In addition to its high penetration of the blood-brain barrier, minocycline is a safe compound commonly used to treat chronic infections. Its several mechanisms of action in neuroprotection -- antiinflammatory and antiapoptotic effects, and protease inhibition -- make it a desirable candidate as therapy for acute neurologic injury, such as ischemic stroke. Minocycline is ready for clinical trials of acute neurologic injury.

Topics: Animals; Anti-Bacterial Agents; Anti-Inflammatory Agents; Apoptosis; Brain Injuries; Humans; Hypoxia-Ischemia, Brain; Matrix Metalloproteinases; Minocycline; Neuroprotective Agents; Stroke

The vascular events that happen during ischemic stroke worsen outcomes in patients by causing edema, hemorrhagic transformation, and general neurologic tissue compromise. In the past 2 decades, clinical trials in patients after ischemic stroke focused on neuroprotection, but these strategies have failed in providing actual benefit. Vascular protection represents a new field to be explored in acute ischemic stroke in order to develop new approaches to therapeutic intervention.. We identified tactics likely to provide vascular protection in patients with ischemic stroke. These tactics are based on knowledge of the molecular processes involved.. The pathologic processes due to vascular injury after an occlusion of a cerebral artery can be separated into acute (those occurring within hrs), subacute (hrs to days), and chronic (days to mo). Targets for intervention can be identified for all three stages. In the acute phase, superoxide is the predominant mediator, followed by inflammatory mediators and proteases in the subacute phase. In the chronic phase, proapoptotic gene products have been implicated. Many already-marketed therapeutic agents (statins, angiotensin modulators, erythropoietin, minocycline, and thiazolidinediones), with proven safety in patients, have been shown to have activity against some of the key targets of vascular protection.. Currently available pharmacologic agents are poised for clinical trials of vascular protection after acute ischemic stroke.

Topics: Acute Disease; Angiotensin-Converting Enzyme Inhibitors; Brain; Brain Edema; Brain Ischemia; Cerebral Hemorrhage; Chronic Disease; Erythropoietin; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Minocycline; Stroke; Thiazolidinediones; Thrombolytic Therapy

Topics: Animals; Anti-Inflammatory Agents; Brain Ischemia; Enzyme Inhibitors; Humans; Minocycline; Mitogen-Activated Protein Kinases; Neuroprotective Agents; p38 Mitogen-Activated Protein Kinases; Stroke; Tetracyclines

Minocycline as an antibiotic has been found to have neuroprotective effect on neurodegenerative diseases. This study was aimed at determining the efficacy of minocycline adjunct to aspirin in improving neurological outcomes of ischemic stroke during 3-month follow-up.. In an open-label evaluator-blinded trial, 60 patients with ischemic stroke were allocated into two groups to receive either 200 mg of oral minocycline daily for 5 days during 6-24 h following onset of signs and symptoms, or not receiving any, as control; all patients also received 100 mg of aspirin daily. Clinical assessment at baseline and on days 30, 60, and 90 was performed using National Institutes of Health Stroke Scale (NIHSS) score.. Fifty-three patients (88.3%) completed the study. Females in the treatment and control groups were 53.8% and 51.9%, respectively (P = 0.884). Among all patients, NIHSS score was significantly lower in the minocycline-treated compared with control on day 90 (minocycline median 4, interquartile range 4-7, control median 7, interquartile range 5-8, P = 0.031). Among males, NIHSS was lower in minocycline-treated compared with controls on days 30, 60, and 90 (P < 0.05); however, females showed no significant differences at the same times compared with controls. No adverse outcomes including myocardial infarction, recurrent stroke, and mortality were observed in the both groups.. Patients with ischemic stroke who received oral minocycline daily for 5 days had significantly better neurological outcomes on day 90 than controls. However, females showed no significant clinical improvement compared to males.

Topics: Aged; Aspirin; Female; Humans; Male; Middle Aged; Minocycline; Neuroprotective Agents; Platelet Aggregation Inhibitors; Sex Factors; Single-Blind Method; Stroke; United States

Minocycline, in animal models and 2 small randomized controlled human trials, is a promising neuroprotective agent in acute stroke. We analyzed the efficacy and safety of intravenous minocycline in acute ischemic and hemorrhagic stroke.. A multicenter prospective randomized open-label blinded end point evaluation pilot study of minocycline 100 mg administered intravenously, commenced within 24 hours of onset of stroke, and continued 12 hourly for a total of 5 doses, versus no minocycline. All participants received routine stroke care. Primary end point was survival free of handicap (modified Rankin Scale, ≤2) at day 90.. Ninety-five participants were randomized; 47 to minocycline and 48 to no minocycline. In the intention-to-treat population, 29 of 47 (65.9%) allocated minocycline survived free of handicap compared with 33 of 48 (70.2%) allocated no minocycline (rate ratio, 0.94; 95% confidence interval, 0.71-1.25 and odds ratio, 0.73; 95% CI, 0.31-1.71). A meta-analysis of the 3 human trials suggests minocycline may increase the odds of handicap-free survival by 3-fold (odds ratio, 2.99; 95% CI, 1.74-5.16) but there was substantial heterogeneity among the trials.. In this pilot study of a small sample of acute stroke patients, intravenous minocycline was safe but not efficacious. The study was not powered to identify reliably or exclude a modest but clinically important treatment effect of minocycline. Larger trials would improve the precision of the estimates of any treatment effect of minocycline.. http://www.anzctr.org.au. Unique identifier: ACTRN12612000237886.

Topics: Administration, Intravenous; Aged; Aged, 80 and over; Anti-Bacterial Agents; Brain Ischemia; Cerebral Hemorrhage; Female; Humans; Male; Middle Aged; Minocycline; Pilot Projects; Severity of Illness Index; Stroke; Treatment Outcome

Plasma matrix metalloproteinase-9 levels predict posttissue plasminogen activator (tPA) hemorrhage.. The authors investigated the effect of minocycline on plasma matrix metalloproteinase-9 in acute ischemic stroke in the Minocycline to Improve Neurological Outcome in Stroke (MINOS) trial and a comparison group.. Matrix metalloproteinase-9 level decreased at 72 hours compared with baseline in MINOS (tPA, P=0.0022; non-tPA, P=0.0066) and was lower than in the non-MINOS comparison group at 24 hours (tPA, P<0.0001; non-tPA, P=0.0019).. Lower plasma matrix metalloproteinase-9 was seen among tPA-treated subjects in the MINOS trial. Combining minocycline with tPA may prevent the adverse consequences of thrombolytic therapy through suppression of matrix metalloproteinase-9 activity.

Topics: Aged; Anti-Bacterial Agents; Brain Ischemia; Female; Fibrinolytic Agents; Humans; Infusions, Intravenous; Male; Matrix Metalloproteinase 9; Matrix Metalloproteinase Inhibitors; Middle Aged; Minocycline; Stroke; Thrombolytic Therapy; Tissue Plasminogen Activator

Ischemic animal model studies have shown a neuroprotective effect of minocycline.. To analyze the effect of minocycline treatment in human acute ischemic stroke.. We performed an open-label, evaluator-blinded study. Minocycline at a dosage of 200 mg was administered orally for 5 days. The therapeutic window of time was 6 to 24 hours after onset of stroke. Data from NIH Stroke Scale (NIHSS), modified Rankin Scale (mRS), and Barthel Index (BI) were evaluated. The primary objective was to compare changes from baseline to day 90 in NIHSS in the minocycline group vs placebo.. One hundred fifty-two patients were included in the study. Seventy-four patients received minocycline treatment, and 77 received placebo. NIHSS and mRS were significantly lower and BI scores were significantly higher in minocycline-treated patients. This pattern was already apparent on day 7 and day 30 of follow-up. Deaths, myocardial infarctions, recurrent strokes, and hemorrhagic transformations during follow-up did not differ by treatment group.. Patients with acute stroke had significantly better outcome with minocycline treatment compared with placebo. The findings suggest a potential benefit of minocycline in acute ischemic stroke.

Topics: Acute Disease; Aged; Anti-Bacterial Agents; Anti-Inflammatory Agents; Apoptosis; Cerebral Hemorrhage; Female; Gliosis; Humans; Hypoxia-Ischemia, Brain; Male; Microglia; Middle Aged; Minocycline; Mortality; Myocardial Infarction; Neuroprotective Agents; Placebos; Secondary Prevention; Signal Transduction; Single-Blind Method; Stroke; Treatment Outcome

Animal models of cerebral ischemia have improved our understanding of the pathophysiology and mechanisms involved in stroke, as well as the investigation of potential therapies. The potential of zebrafish to model human diseases has become increasingly evident. The availability of these models allows for an increased understanding of the role of chemical exposure in human conditions and provides essential tools for mechanistic studies of disease. To evaluate the potential neuroprotective properties of minocycline against ischemia and reperfusion injury in zebrafish and compare them with other standardized models. In vitro studies with BV-2 cells were performed, and mammalian transient middle cerebral artery occlusion (tMCAO) was used as a comparative standard with the zebrafish stroke model. Animals were subjected to ischemia and reperfusion injury protocols and treated with minocycline. Infarction size, cytokine levels, oxidative stress, glutamate toxicity, and immunofluorescence for microglial activation, and behavioral test results were determined and compared. Administration of minocycline provided significant protection in the three stroke models in different parameters analyzed. Both experimental models complement each other in their particularities. The proposal also strengthens the findings in the literature in rodent models and allows the validation of alternative models so that they can be used in further research involving diseases with ischemia and reperfusion injury.

Topics: Animals; Brain Ischemia; Disease Models, Animal; Humans; Infarction, Middle Cerebral Artery; Mammals; Minocycline; Neuroprotective Agents; Reperfusion Injury; Stroke; Zebrafish

Ischemic stroke is the most common cause of adult disability and one of the leading causes of death worldwide, with a serious socio-economic impact. In the present work, we used a new thromboembolic model, recently developed in our lab, to induce focal cerebral ischemic (FCI) stroke in rats without reperfusion. We analyzed selected proteins implicated in the inflammatory response (such as the RNA-binding protein HuR, TNFα, and HSP70) via immunohistochemistry and western blotting techniques. The main goal of the study was to evaluate the beneficial effects of a single administration of minocycline at a low dose (1 mg/kg intravenously administered 10 min after FCI) on the neurons localized in the penumbra area after an ischemic stroke. Furthermore, given the importance of understanding the crosstalk between molecular parameters and motor functions following FCI, motor tests were also performed, such as the Horizontal Runway Elevated test, CatWalk™ XT, and Grip Strength test. Our results indicate that a single administration of a low dose of minocycline increased the viability of neurons and reduced the neurodegeneration caused by ischemia, resulting in a significant reduction in the infarct volume. At the molecular level, minocycline resulted in a reduction in TNFα content coupled with an increase in the levels of both HSP70 and HuR proteins in the penumbra area. Considering that both HSP70 and TNF-α transcripts are targeted by HuR, the obtained results suggest that, following FCI, this RNA-binding protein promotes a protective response by shifting its binding towards HSP70 instead of TNF-α. Most importantly, motor tests showed that reduced inflammation in the brain damaged area after minocycline treatment directly translated into a better motor performance, which is a fundamental outcome when searching for new therapeutic options for clinical practice.

Topics: Animals; Brain Ischemia; Disease Models, Animal; Ischemic Stroke; Minocycline; Neurons; Rats; Rats, Sprague-Dawley; Stroke; Tumor Necrosis Factor-alpha

Astrocytes, together with microglia, play important roles in the non-infectious inflammation and scar formation at the brain infarct during ischemic stroke. After ischemia occurs, these become highly reactive, accumulate at the infarction, and release various inflammatory signaling molecules. The regulation of astrocyte reactivity and function surrounding the infarction largely depends on intercellular communication with microglia. However, the mechanisms involved remain unclear. Furthermore, recent molecular biological studies have revealed that astrocytes are highly divergent under both resting and reactive states, whereas it has not been well reported how the communication between microglia and astrocytes affects astrocyte divergency during ischemic stroke. Minocycline, an antibiotic that reduces microglial activity, has been used to examine the functional roles of microglia in mice. In this study, we used a mouse photothrombotic ischemic stroke model to examine the characteristics of astrocytes after the administration of minocycline during ischemic stroke. Minocycline increased astrocyte reactivity and affected the localization of astrocytes in the penumbra region. Molecular characterization revealed that the induced expression of mRNA encoding the fatty acid binding protein 7 (FABP7) by photothrombosis was enhanced by the minocycline administration. Meanwhile, minocycline did not significantly affect the phenotype or class of astrocytes. The expression of Fabp7 mRNA was well correlated with that of tumor-necrosis factor α (TNFα)-encoding Tnf mRNA, indicating that a correlated expression of FABP7 from astrocytes and TNFα is suppressed by microglial activity.

Topics: Animals; Astrocytes; Brain Infarction; Disease Models, Animal; Ischemic Stroke; Mice; Microglia; Minocycline; RNA, Messenger; Stroke; Tumor Necrosis Factor-alpha

Hypoxia caused by ischemia induces acidosis and neuroexcitotoxicity, resulting in neuronal death in the central nervous system (CNS). Monoacylglycerol lipase (MAGL) is a modulator of 2-arachidonoylglycerol (2-AG), which is involved in retrograde inhibition of glutamate release in the endocannabinoid system. In the present study, we used positron emission tomography (PET) to monitor MAGL-positive neurons and neuroinflammation in the brains of ischemic rats. Additionally, we performed PET imaging to evaluate the neuroprotective effects of an MAGL inhibitor in an ischemic injury model.

Topics: Animals; Arachidonic Acids; Benzodioxoles; Brain; Brain Ischemia; Carbon Radioisotopes; Cell Hypoxia; Disease Models, Animal; Endocannabinoids; Glycerides; Infarction, Middle Cerebral Artery; Ischemic Stroke; Male; Minocycline; Monoacylglycerol Lipases; Neuroprotective Agents; Piperidines; Positron-Emission Tomography; Rats; Rats, Sprague-Dawley; Stroke; Tomography, X-Ray Computed

Altered neuronal connectivity in peri-infarct tissue is an important contributor to both the spontaneous recovery of neurological function that commonly develops after stroke and improvements in recovery that have been induced by experimental treatments in animal models. Microglia and astrocytes are primary determinants of the environment in peri-infarct tissue and hence strongly influence the potential for neuronal plasticity. However, the specific roles of these cells and the timing of critical changes in their function are not well understood. Minocycline can protect against ischemic damage and promote recovery. These effects are usually attributed, at least partially, to the ability of this drug to suppress microglial activation. This study tested the ability of minocycline treatment early after stroke to modify reactive responses in microglia and astrocytes and improve recovery.. Stroke was induced by photothrombosis in the forelimb sensorimotor cortex of Sprague-Dawley rats. Minocycline was administered for 2 days after stroke induction and the effects on forelimb function assessed up to 28 days. The responses of peri-infarct Iba1-positive cells and astrocytes were evaluated using immunohistochemistry and Western blots.. Initial characterization showed that the numbers of Iba1-positive microglia and macrophages decreased in peri-infarct tissue at 24 h then increased markedly over the next few days. Morphological changes characteristic of activation were readily apparent by 3 h and increased by 24 h. Minocycline treatment improved the rate of recovery of motor function as measured by a forelimb placing test but did not alter infarct volume. At 3 days, there were only minor effects on core features of peri-infarct microglial reactivity including the morphological changes and increased density of Iba1-positive cells. The treatment caused a decrease of 57% in the small subpopulation of cells that expressed CD68, a marker of phagocytosis. At 7 days, the expression of glial fibrillary acidic protein and vimentin was markedly increased by minocycline treatment, indicating enhanced reactive astrogliosis.. Early post-stroke treatment with minocycline improved recovery but had little effect on key features of microglial activation. Both the decrease in CD68-positive cells and the increased activation of astrogliosis could influence neuronal plasticity and contribute to the improved recovery.

Topics: Animals; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Astrocytes; Brain Infarction; Calcium-Binding Proteins; Disease Models, Animal; Dose-Response Relationship, Drug; Forelimb; Intracranial Thrombosis; Male; Microfilament Proteins; Microglia; Minocycline; Nerve Tissue Proteins; Psychomotor Performance; Rats; Rats, Sprague-Dawley; Recovery of Function; Stroke; Time Factors

Stroke induced white matter injury can induce marked neurological deficits even after relatively small infarcts, due to the tightly packed nature of white matter tracts especially in certain areas in the brain. Many drugs which were successful in the pre-clinical trials failed in clinical trials, which was attributed in part to the focus on grey matter injury completely and ignoring their effect on white matter. In this work we selected two known neuroprotective drugs (minocycline and progesterone) and examined their effect on white matter injury after focal cerebral ischemia/reperfusion injury in rats. Focal cerebral ischemia was induced in male Wistar rats (one-hour ischemia followed by reperfusion). Progesterone and minocycline were administered immediately after reperfusion onset. Infarct size, microglial activation and white matter injury were assessed and compared between the treatment and no-treatment groups and Sham operated animals. Our data showed that both progesterone and minocycline reduced infarct size, microglial activation and white matter injury. This work shows a new neuroprotective mechanism of both drugs, via white matter injury reduction, that can be exploited for stroke management. While the utility of either drugs as a sole agent in the management of stroke is questionable, there is a value of using either drugs as an adjuvant therapy to traditional stroke therapy, making use of the white matter protective effect that would improve outcome and facilitate healing after stroke.

Topics: Animals; Brain Ischemia; Female; Male; Minocycline; Neuroprotective Agents; Progesterone; Rats; Rats, Wistar; Reperfusion Injury; Stroke; White Matter

We report an original case of reversible antiphospholipid syndrome (APS) due to minocycline in a young male patient who experienced recurrent strokes while taking minocycline. He started minocycline therapy (50 mg twice daily) at 15 years old for acne. After three years of treatment, the patient experienced a lateral medullary syndrome. He was treated with aspirin while minocycline was continued. Eighteen months later, the patient complained about horizontal binocular diplopia. MRI revealed an infarct of the oculomotor nerve nucleus. Laboratory investigations revealed high titers of anti-beta 2 glycoprotein 1 (antiβ2GP1) antibodies of 470 U/ml (normal range <15 U/ml) and antiphosphatidylethanolamine antibodies of 137.4 U/ml (normal range <18 U/ml). Other laboratory tests were normal. Six weeks after discontinuation of minocycline, anti-β2GP1 antibodies decreased to 335 U/ml and to 36 U/ml at six months and then remained negative for six years. Many drugs have been considered as possibly causing APS but only in a limited number of patients. To our knowledge this is the first case of drug-induced APS with complete disappearance of high titers of anti-β2GP1 antibodies after minocycline withdrawal. This case also illustrates the need to monitor the levels of antiphospholipid antibodies, even though initial values are high and confirmed after 12 weeks.

Topics: Anti-Bacterial Agents; Antibodies, Antiphospholipid; Antiphospholipid Syndrome; beta 2-Glycoprotein I; Humans; Lateral Medullary Syndrome; Magnetic Resonance Imaging; Male; Minocycline; Stroke; Treatment Outcome; Vasculitis; Young Adult

Minocycline, a tetracycline antibiotic, has shown anti-inflammatory effects in cerebral ischemia and neurodegenerative disease; however, the molecular mechanisms underlying this effect have not been clearly identified. Since NLRP3 inflammasome activation controls the maturation and release of proinflammatory cytokines, especially interleukin-1β (IL-1β) and IL-18 in ischemia stroke, we suppose that minocycline may be involved in the regulation of NLRP3 inflammasome activation.. We investigated the effects of minocycline on NLRP3 inflammasome activation using the transient middle cerebral artery occlusion (tMCAO) mouse model and an in vitro oxygen-glucose deprivation/reoxygenation injury model in BV2 microglial cells.. We found that minocycline administrated 1 h after reperfusion can improve neurological disorder, reduce infarct volume, and alleviate cerebral edema. Meanwhile, we showed that minocycline prevented the activation of microglias and attenuated NLRP3 inflammasome signaling after tMCAO injury. Furthermore, we found that the pretreatment of minocycline significantly inhibited signal 1 and signal 2 of NLRP3 inflammasome activation in BV2 cells.. We demonstrated that minocycline can ameliorate ischemia-induced brain damage via inhibiting NLRP3 inflammasome activation.

Topics: Animals; Anti-Bacterial Agents; Brain Ischemia; Cell Line; Dose-Response Relationship, Drug; Inflammasomes; Male; Mice; Mice, Inbred C57BL; Microglia; Minocycline; NLR Family, Pyrin Domain-Containing 3 Protein; Stroke

We investigated the neuroprotective properties of single doses of minocycline and ozagrel when administered prior to stroke. Male Sprague-Dawley rats were assigned randomly to one of the following groups: (1) control (Con) group (n=10), (2) minocycline (Mino) group (n=10), (3) sodium ozagrel (SO) group (n=10). Rats were treated with a single dose of minocycline or ozagrel at 30min before stroke. A middle cerebral artery occlusion (MCAO) was made at 30min after drug administration and reperfusion was done. The rats were subjected to a neurobehavioral test at days 1, 3 and 7 after MCAO. The cerebral ischemic volume was quantified by MetaMorph imaging software after TTC staining. The neuronal cell survival and astrocytes expansion were assessed by the NeuN and GFAP immunohistofluorescence staining. Apoptosis was detected by the TUNEL assay. We statistically analyzed and compared the results with each other. Mino and SO groups had neuroprotective effect and showed a better behavioral performance of adhesive removal and treadmill test at 7 days after stroke. Mino and SO groups also showed a smaller infarct volume than control group at 7 days after stroke. Immunohistofluorescence staining showed a higher number of NeuN positive cells, lower activated astrocytes in GFAP and a lower apoptosis in TUNEL staining. This study showed that single doses of minocycline and ozagrel prior to stroke had neuroprotective effects. These agents will be useful not only in post-stroke therapy but also in stroke prevention in several cerebrovascular procedures like carotid endarterectomy, bypass procedure, endovascular angioplasty, thromboembolectomy or thrombolysis.

Topics: Animals; Apoptosis; Astrocytes; Brain; Cell Survival; Disease Models, Animal; Fibrinolytic Agents; Infarction, Middle Cerebral Artery; Ischemic Attack, Transient; Male; Methacrylates; Minocycline; Neurons; Neuroprotective Agents; Neuropsychological Tests; Random Allocation; Rats, Sprague-Dawley; Stroke; Treatment Outcome

Central post-stroke pain (CPSP) including thalamic pain is one of the most troublesome sequelae that can occur after a cerebrovascular accident. Although the prevalence of CPSP among stroke patients is relatively low, the persistent, often treatment-refractory, painful sensations can be a major problem and decrease the affected patient's quality of life. To better understand of the pathophysiological basis of CPSP, we developed and characterized a new mouse model of thalamic CPSP. This model is based on a hemorrhagic stroke lesion with collagenase in the ventral posterolateral nucleus of the thalamus. Histopathological analysis indicated that the thalamic hemorrhage produced a relatively confined lesion that destroys the tissue within the initial bleed, and also showed the presence of activated microglia adjacent to the core of hemorrhagic lesions. Behavioral analysis demonstrated that the animals displayed diclofenac-, morphine- or pregabalin-resistant mechanical allodynia and thermal hyperalgesia of the hind paw contralateral to the lesion for over 112 days. However, we found that minocycline, a microglial inhibitor, significantly ameliorated mechanical allodynia and thermal hyperalgesia. These results suggest that this model might be proved as a useful animal model for studying the neuropathology of thalamic syndrome, and developing improved therapeutics for CPSP.

Topics: Analgesics, Non-Narcotic; Animals; Cerebral Hemorrhage; Collagenases; Disease Models, Animal; Hyperalgesia; Male; Mice; Mice, Inbred C57BL; Minocycline; Nociceptive Pain; Pain Threshold; Stroke; Thalamic Diseases; Ventral Thalamic Nuclei

Using [(18) F]PBR06 positron emission tomography (PET) to characterize the time course of stroke-associated neuroinflammation (SAN) in mice, to evaluate whether brain microglia influences motor function after stroke, and to demonstrate the use of [(18) F]PBR06 PET as a therapeutic assessment tool.. Stroke was induced by transient middle cerebral artery occlusion (MCAO) in Balb/c mice (control, stroke, and stroke with poststroke minocycline treatment). [18 F]PBR06 PET/CT imaging, rotarod tests, and immunohistochemistry (IHC) were performed 3, 11, and 22 days poststroke induction (PSI).. The stroke group exhibited significantly increased microglial activation, and impaired motor function. Peak microglial activation was 11 days PSI. There was a strong association between microglial activation, motor function, and microglial protein expression on IHC. Minocycline significantly reduced microglial activation and improved motor function by day 22 PSI.. [18 F]PBR06 PET imaging noninvasively characterizes the time course of SAN, and shows increased microglial activation is associated with decreased motor function.

Topics: Acetanilides; Animals; Contrast Media; Female; Fluorine Radioisotopes; Mice; Mice, Inbred BALB C; Microglia; Minocycline; Motor Activity; Positron-Emission Tomography; Radiopharmaceuticals; Stroke

Poststroke hyperglycemia is associated with resistance to tissue plasminogen activator (tPA) reperfusion, higher risk of intracerebral hemorrhage, and worse neurological outcomes. In this study, we asked whether minocycline combined with intravenous tPA may ameliorate inflammation and brain injury after focal embolic stroke in type 1 diabetic rats.. Type 1 diabetic rats were subjected to a focal embolic stroke. Three treatment groups were used: (1) saline at 1.5 hours after stroke; (2) tPA alone at 1.5 hours after stroke; (3) combined minocycline (intravenously) at 1 hour plus tPA at 1.5 hours, and second treatment of minocycline (intraperitoneally) at 12 hours after stroke. Acute brain tissue damages were assessed at 24 hours after stroke. Inflammatory biomarkers interleukin-1β and matrix metalloproteinases 2 and 9 were examined in plasma. Neutrophil infiltration, microglia activation, matrix metalloproteinase activation, and degradation of the tight junction protein claudin-5 were examined in the brain.. Compared with saline or tPA alone treatments, minocycline plus tPA combination therapy significantly reduced brain infarction, intracerebral hemorrhage, and hemispheric swelling at 24 hours after stroke. The combination also significantly suppressed the elevated plasma levels of matrix metalloproteinase-9 and interleukin-1β up to 24 hours after stroke. At 16 hours after stroke, neutrophil infiltration, microglia activation, matrix metalloproteinase-9, and tight junction protein claudin-5 degradation in the peri-infarct brain tissues were also significantly attenuated by the combination therapy.. Combination therapy with minocycline plus tPA may be beneficial in ameliorating inflammation and reducing infarction, brain swelling, and hemorrhage after ischemic stroke with diabetes mellitus/hyperglycemia.

Topics: Animals; Anti-Bacterial Agents; Cerebral Hemorrhage; Claudin-5; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Disease Models, Animal; Drug Therapy, Combination; Fibrinolytic Agents; Interleukin-1beta; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Minocycline; Rats; Rats, Wistar; Risk Factors; Streptozocin; Stroke; Tissue Plasminogen Activator

We used a modified pial vessel disruption (PVD) protocol with adult male Wistar rats to mimic small-vessel stroke in the cerebral cortex. Within 3 weeks, this lesion develops into a single lacuna-like cavity, which is fluid-filled and encapsulated by reactive astrocytes. Minocycline treatment that commences 1 hr after lesion and continues for 6 days prevents the cavitation and causes a filling of the lesion with reactive astrocytes and no barrier. Here, we determined whether inhibition of matrix metalloproteinases-2 and -9 (MMPs) mediates this minocycline action. Confocal microscopy revealed increased punctate staining of MMPs inside the lesion sites after 2 days of PVD. Astrocytes lined the lesion border but showed sparse localization inside the lesion. In contrast, increased MMP levels inside the lesion coincided with increased ED1 or OX-42 immunostaining, suggesting that MMP elevation reflected increased secretions from microglia/macrophages. Imaging analyses also revealed that minocycline administered for 2 days before animal euthanasia, significantly decreased MMP levels within the lesion. Moreover, Western blot analysis of cortical tissue extracts showed a significant 30-40% upregulation of MMPs 2 days after lesion. Minocycline administered 2 hr before the lesion significantly inhibited both MMP-9 and MMP-2 levels by ∼40%. In contrast, minocycline administered 1 hr after the lesion only decreased MMP-9 levels by ∼30%. Because MMP inhibition with batimastat injection also prevented cavity formation at 21 days, we conclude that minocycline prevented the creation of a lacuna-like cyst in the cerebral cortex by inhibiting the MMP secretion from microglia in the affected tissue.

Topics: Analysis of Variance; Animals; CD11b Antigen; Disease Models, Animal; Ectodysplasins; Gene Expression Regulation, Enzymologic; Glial Fibrillary Acidic Protein; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Microglia; Minocycline; Phenylalanine; Protease Inhibitors; Rats; Rats, Wistar; Stroke; Stroke, Lacunar; Thiophenes; Time Factors

This study sought to evaluate whether the therapeutic effects of an anti-inflammatory drug such as minocycline could be monitored by serial ultrasmall superparamagnetic particles of iron oxide (USPIO)-enhanced MRI in experimental stroke.. Mice received a three-dose minocycline treatment (n = 12) or vehicle (n = 12) after permanent middle cerebral artery occlusion. USPIOs were administered 5 h post-surgery. MRI was performed before, 24 h and 48 h post-USPIO administration. MRI endpoints were the extent of signal abnormalities on R2 maps (=1/T2) and quantitative R2 changes over time (∆R2). Post-mortem brains were prepared either for immunohistology (n = 16) or for iron dosage (n = 8).. As expected, treatment with minocycline significantly reduced infarct size, blood-brain barrier permeability and F4/80 immunostaining for microglia/macrophages. Areas of R2 maps > 35 ms(-1) also appeared significantly decreased in minocycline-treated mice (ANOVA for repeated measures, P = 0.017). There was a fair correlation between these areas and the amount of iron in the brain (R(2) = 0.69, P = 0.010), but no significant difference in ∆R2 was found between the two groups.. This study showed that the extent of signal abnormalities on R2 maps can be used as a surrogate marker to detect minocycline effects in a murine experimental model of stroke.

Topics: Analysis of Variance; Animals; Contrast Media; Dextrans; Disease Models, Animal; Magnetic Resonance Imaging; Magnetite Nanoparticles; Mice; Minocycline; Stroke

We explored whether the modulation of microglia activation with minocycline is beneficial to the therapeutic actions of bone marrow mononuclear cells (BMMCs) transplanted after experimental stroke. Male Wistar adult rats were divided in four experimental groups: ischemic control saline treated (G1, N = 6), ischemic minocycline treated (G2, N = 5), ischemic BMMC treated (G3, N = 5), and ischemic minocycline/BMMC treated (G4, N = 6). There was a significant reduction in the number of ED1+ cells in G3 animals (51.31 ± 2.41, P < 0.05), but this effect was more prominent following concomitant treatment with minocycline (G4 = 29.78 ± 1.56). There was conspicuous neuronal preservation in the brains of G4 animals (87.97 ± 4.27) compared with control group (G1 = 47.61 ± 2.25, P < 0.05). The behavioral tests showed better functional recovery in animals of G2, G3, and G4, compared with G1 and baseline (P < 0.05). The results suggest that a proper modulation of microglia activity may contribute to a more permissive ischemic environment contributing to increased neuroprotection and functional recovery following striatal ischemia.

Topics: Animals; Bone Marrow Cells; Bone Marrow Transplantation; Brain Ischemia; Cells, Cultured; Endothelin-1; Macrophage Activation; Macrophages; Male; Microglia; Minocycline; Neuroprotective Agents; Rats; Rats, Wistar; Recovery of Function; Stroke

Transplantation of neural stem cells (NSCs) offers a novel therapeutic strategy for stroke; however, massive grafted cell death following transplantation, possibly due to a hostile host brain environment, lessens the effectiveness of this approach. Here, we have investigated whether reprogramming NSCs with minocycline, a broadly used antibiotic also known to possess cytoprotective properties, enhances survival of grafted cells and promotes neuroprotection in ischemic stroke. NSCs harvested from the subventricular zone of fetal rats were preconditioned with minocycline in vitro and transplanted into rat brains 6 h after transient middle cerebral artery occlusion. Histological and behavioral tests were examined from days 0-28 after stroke. For in vitro experiments, NSCs were subjected to oxygen-glucose deprivation and reoxygenation. Cell viability and antioxidant gene expression were analyzed. Minocycline preconditioning protected the grafted NSCs from ischemic reperfusion injury via upregulation of Nrf2 and Nrf2-regulated antioxidant genes. Additionally, preconditioning with minocycline induced the NSCs to release paracrine factors, including brain-derived neurotrophic factor, nerve growth factor, glial cell-derived neurotrophic factor, and vascular endothelial growth factor. Moreover, transplantation of the minocycline-preconditioned NSCs significantly attenuated infarct size and improved neurological performance, compared with non-preconditioned NSCs. Minocycline-induced neuroprotection was abolished by transfecting the NSCs with Nrf2-small interfering RNA before transplantation. Thus, preconditioning with minocycline, which reprograms NSCs to tolerate oxidative stress after ischemic reperfusion injury and express higher levels of paracrine factors through Nrf2 up-regulation, is a simple and safe approach to enhance the effectiveness of transplantation therapy in ischemic stroke.

Topics: Animals; Brain Ischemia; Cell Death; Cells, Cultured; Ischemic Preconditioning; Male; Minocycline; Neural Stem Cells; Neuroprotective Agents; Rats; Rats, Sprague-Dawley; Rats, Transgenic; Stem Cell Transplantation; Stroke

In this report, we describe an 88-year-old male stroke patient with unilateral bullous pemphigoid limited to the hemiplegic side. Physical examinations revealed multiple tense bullae with clear and/or bloody contents without apparent erythema on the right thigh and lower leg, accompanied by erosions on the right chest. Histopathologically, no eosinophils were infiltrated into and around the subepidermal bullae. Immunofluorescence revealed deposited and circulating immunoglobulin (Ig)G anti-basement membrane zone antibodies. Immunoblot assays using various antigen sources and enzyme-linked immunosorbent assay revealed that IgG antibodies in this case reacted with unique epitopes between NC16a and C-terminal domains on the 120-kDa LAD-1, the extracellular truncated form of BP180. Three observations were unique in our case. First, the distribution of bullae in our patient was limited to the hemiplegic side. Second, there was no apparent erythema clinically and no eosinophilic infiltration histopathologically. Third, the patient achieved remission without the use of oral corticosteroids. The unusual epitopes in this case may contribute to these phenomena.

Topics: Adrenal Cortex Hormones; Aged; Aged, 80 and over; Autoantigens; Collagen Type XVII; Eosinophils; Hemiplegia; Humans; Male; Minocycline; Niacinamide; Non-Fibrillar Collagens; Pemphigoid, Bullous; Stroke

Topics: Anti-Bacterial Agents; Brain Ischemia; Female; Humans; Male; Matrix Metalloproteinase 9; Minocycline; Stroke

Minocycline is a promising anti-inflammatory and protease inhibitor that is effective in multiple preclinical stroke models. We conducted an early phase trial of intravenous minocycline in acute ischemic stroke.. Following an open-label, dose-escalation design, minocycline was administered intravenously within 6 hours of stroke symptom onset in preset dose tiers of 3, 4.5, 6, or 10 mg/kg daily over 72 hours. Minocycline concentrations for pharmacokinetic analysis were measured in a subset of patients. Subjects were followed for 90 days.. Sixty patients were enrolled, 41 at the highest dose tier of 10 mg/kg. Overall age (65±13.7 years), race (83% white), and sex (47% female) were consistent across the doses. The mean baseline National Institutes of Health Stroke Scale score was 8.5±5.8 and 60% received tissue plasminogen activator. Minocycline infusion was well tolerated with only 1 dose limiting toxicity at the 10-mg/kg dose. No severe hemorrhages occurred in tissue plasminogen activator-treated patients. Pharmacokinetic analysis (n=22) revealed a half-life of approximately 24 hours and linearity of parameters over doses.. Minocycline is safe and well tolerated up to doses of 10 mg/kg intravenously alone and in combination with tissue plasminogen activator. The half-life of minocycline is approximately 24 hours, allowing every 24-hour dosing. Minocycline may be an ideal agent to use with tissue plasminogen activator.

Topics: Aged; Aged, 80 and over; Anti-Inflammatory Agents; Brain Ischemia; Chromatography, High Pressure Liquid; Drug Administration Schedule; Drug Therapy, Combination; Female; Fibrinolytic Agents; Half-Life; Humans; Male; Middle Aged; Minocycline; Severity of Illness Index; Stroke; Time Factors; Tissue Plasminogen Activator; Treatment Outcome

Minocycline is neuroprotective in clinical and experimental stroke studies, due in part to its ability to inhibit poly (ADP-ribose) polymerase. Previous preclinical data have shown that interference with poly (ADP-ribose) polymerase signaling leads to sex-specific neuroprotection, reducing stroke injury only in males. In this study, we show that minocycline is ineffective at reducing ischemic damage in females after middle cerebral artery occlusion, likely due to effects on poly (ADP-ribose) polymerase signaling. Clinical trials must consider possible sex differences in the response to neuroprotective agents, if we hope to translate promising therapies to stroke patients of both sexes.

Topics: Animals; Brain Ischemia; Drug Evaluation, Preclinical; Female; Infarction, Middle Cerebral Artery; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Minocycline; Neuroprotective Agents; Poly(ADP-ribose) Polymerase Inhibitors; Sex Factors; Stroke; Treatment Failure

Topics: Animals; California; Clinical Trials as Topic; Drug Design; Granulocyte Colony-Stimulating Factor; Humans; Minocycline; Neuroprotective Agents; Recombinant Proteins; Stroke; Treatment Outcome

New treatment strategies for acute ischemic stroke must be evaluated in the context of effective reperfusion. Minocycline is a neuroprotective agent that inhibits proteolytic enzymes and therefore could potentially both inactivate the clot lysis effect and decrease the damaging effects of tissue-type plasminogen activator (t-PA). This study aimed to determine the effect of minocycline on t-PA clot lysis and t-PA-induced hemorrhage formation after ischemia.. Fibrinolytic and amidolytic activities of t-PA were investigated in vitro over a range of clinically relevant minocycline concentrations. A suture occlusion model of 3-hour temporary cerebral ischemia in rats treated with t-PA and 2 different minocycline regimens was used. Blood-brain barrier basal lamina components, matrix metalloproteinases (MMPs), hemorrhage formation, infarct size, edema, and behavior outcome were assessed.. Minocycline did not affect t-PA fibrinolysis. However, minocycline treatment at 3 mg/kg IV decreased total protein expression of both MMP-2 (P=0.0034) and MMP-9 (P=0.001 for 92 kDa and P=0.0084 for 87 kDa). It also decreased the incidence of hemorrhage (P=0.019), improved neurologic outcome (P=0.0001 for Bederson score and P=0.0391 for paw grasp test), and appeared to decrease mortality. MMP inhibition was associated with decreased degradation in collagen IV and laminin-alpha1 (P=0.0001).. Combination treatment with minocycline is beneficial in t-PA-treated animals and does not compromise clot lysis. These results also suggest that neurovascular protection by minocycline after stroke may involve direct protection of the blood-brain barrier during thrombolysis with t-PA.

Topics: Animals; Anti-Bacterial Agents; Blood-Brain Barrier; Brain Ischemia; Cerebral Hemorrhage; Drug Evaluation, Preclinical; Fibrinolysis; Gene Expression Regulation; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Minocycline; Neuroprotective Agents; Rats; Rats, Wistar; Stroke; Tissue Plasminogen Activator

Topics: Anti-Bacterial Agents; Drug Evaluation; Humans; Minocycline; Stroke

Matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9) are increased in the brain after experimental ischemic stroke in rats. These two proteases are involved with the degradation of the basal lamina and loss of stability of the blood brain barrier that occurs after ischemia and that is associated with thrombolytic therapy in ischemic stroke. Minocycline is a lipophilic tetracycline and is neuroprotective in several models of brain injury. Minocycline inhibits inflammation, apoptosis and extracellular matrix degradation. In this study we investigated whether delayed minocycline inhibits brain MMPs activated by ischemia in a model of temporary occlusion in Wistar rats.. Both MMP-2 and MMP-9 were elevated in the ischemic tissue as compared to the contra-lateral hemisphere after 3 hours occlusion and 21 hours survival (p < 0.0001 for MMP-9). Intraperitoneal minocycline at 45 mg/kg concentration twice a day (first dose immediately after the onset of reperfusion) significantly reduced gelatinolytic activity of ischemia-elevated MMP-2 and MMP-9 (p < 0.0003). Treatment also reduced protein concentration of both enzymes (p < 0.038 for MMP-9 and p < 0.018 for MMP-2). In vitro incubation of minocycline in concentrations as low as 0.1 mug/ml with recombinant MMP-2 and MMP-9 impaired enzymatic activity and MMP-9 was more sensitive at lower minocycline concentrations (p < 0.05).. Minocycline inhibits enzymatic activity of gelatin proteases activated by ischemia after experimental stroke and is likely to be selective for MMP-9 at low doses. Minocycline is a potential new therapeutic agent to acute treatment of ischemic stroke.

Topics: Animals; Anti-Inflammatory Agents; Apoptosis; Blood-Brain Barrier; Brain; Brain Ischemia; Disease Models, Animal; Drug Administration Schedule; Encephalitis; Enzyme Activation; Enzyme Inhibitors; Extracellular Matrix; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Matrix Metalloproteinase Inhibitors; Matrix Metalloproteinases; Minocycline; Nerve Degeneration; Neuroprotective Agents; Rats; Rats, Wistar; Stroke; Time Factors; Treatment Outcome

Inflammatory reactions occurring in the brain after ischemia may contribute to secondary damage. In the present study effects of minocycline, an anti-inflammatory agent, alone or in combination with mild hypothermia, on focal embolic brain ischemia have been examined. Focal ischemic injury was induced by embolizing a preformed clot into the middle cerebral artery (MCA). Infarct volume was measured at 48 h after the injury. Administration of minocycline alone or minocycline plus mild hypothermia reduced infarct volume significantly. However, mild hypothermia in combination with minocycline did not show any additive effect. These results suggest that minocycline is beneficial in focal ischemic brain injury, and the lack of the enhanced neuroprotection may be due to the brief exposure to hypothermia.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Brain Ischemia; Combined Modality Therapy; Hypothermia, Induced; Infarction, Middle Cerebral Artery; Intracranial Embolism; Male; Minocycline; Rats; Rats, Wistar; Stroke; Survival Analysis

Inflammatory reactions occurring in the brain after ischemia may contribute to secondary damage. In the present study, effects of minocycline, an anti-inflammatory agent, alone or in combination with mild hypothermia on focal embolic cerebral ischemia have been examined.. Focal ischemic injury was induced by embolizing a preformed clot into the middle cerebral artery (MCA). Infarction volume was measured at 48 h after the injury. Mortality was also recorded.. Delayed administration of minocycline alone or delayed minocycline plus delayed mild hypothermia reduced the infarction volume significantly. However, delayed mild hypothermia alone was not protective and delayed mild hypothermia in combination with minocycline did not show any additive effect.. These results suggest that minocycline is beneficial in focal ischemic brain injury, and the lack of the enhanced neuroprotection may be due to the brief exposure to hypothermia.

Topics: Animals; Disease Models, Animal; Hypothermia, Induced; Infarction, Middle Cerebral Artery; Intracranial Embolism; Male; Minocycline; Neuroprotective Agents; Rats; Rats, Wistar; Stroke; Treatment Outcome