Suppression of MMP-9 by doxycycline in brain arteriovenous malformations

Cerebral cavernous malformations - An overview on genetics, clinical aspects and therapeutic strategies

Cerebral cavernous malformations (CCMs) are abnormally packed blood vessels lined with endothelial cells, that do not exhibit intervening tight junctions, lack muscular and elastic layers and are usually surrounded by hemosiderin and gliosis. CCMs may be sporadic or familial autosomal dominant (FCCMs) caused by loss of function mutations in CCM1 (KRIT1), CCM2 (MGC4607), and CCM3 (PDCD10) genes. In the FCCMs, patients have multiple CCMs, different family members are affected, and developmental venous anomalies are absent. CCMs may be asymptomatic or may manifest with focal neurological deficits with or without associated hemorrhage andseizures. Recent studies identify a digenic "triple-hit" mechanism involving the aquisition of three distinct genetic mutations that culminate in phosphatidylinositol-3-kinase (PIK3CA) gain of function, as the basis for rapidly growing and clinically symptomatic CCMs. The pathophysiology of CCMs involves signaling aberrations in the neurovascular unit, including proliferative dysangiogenesis, blood-brain barrier hyperpermeability, inflammation and immune mediated processes, anticoagulant vascular domain, and gut microbiome-driven mechanisms. Clinical trials are investigating potential therapies, magnetic resonance imaging and plasma biomarkers for hemorrhage and CCMs-related epilepsy, as well as different techniques of neuronavigation and neurosonology to guide surgery in order to minimize post-operatory morbidity and mortality. This review addresses the recent data about the natural history, genetics, neuroimaging and therapeutic approaches for CCMs.

Defining the Role of Oral Pathway Inhibitors as Targeted Therapeutics in Arteriovenous Malformation Care

Arteriovenous malformations (AVMs) are vascular malformations that are prone to rupturing and can cause significant morbidity and mortality in relatively young patients. Conventional treatment options such as surgery and endovascular therapy often are insufficient for cure. There is a growing body of knowledge on the genetic and molecular underpinnings of AVM development and maintenance, making the future of precision medicine a real possibility for AVM management. Here, we review the pathophysiology of AVM development across various cell types, with a focus on current and potential druggable targets and their therapeutic potentials in both sporadic and familial AVM populations.

Hematologic and Inflammatory Predictors of Outcome in Patients with Brain Arteriovenous Malformations

OBJECTIVE

This study investigated the prognostic value of admission blood counts for arteriovenous malformation (AVM) outcomes and compared admission blood counts for patients with ruptured and unruptured AVMs.

METHODS

A retrospective analysis of patients who underwent surgical treatment for a ruptured cerebral AVM between February 1, 2014, and March 31, 2020, was conducted. The primary outcome was poor neurologic outcome, defined as a modified Rankin Scale score ≥2 in patients with unruptured AVMs or >2 in patients with ruptured AVMs.

RESULTS

Of 235 included patients, 80 (34%) had ruptured AVMs. At admission, patients with ruptured AVMs had a significantly lower mean (SD) hemoglobin level (12.78 [2.07] g/dL vs. 13.71 [1.60] g/dL, P < 0.001), hematocrit (38.1% [5.9%] vs. 40.7% [4.6%], P < 0.001), lymphocyte count (16% [11%] vs. 26% [10%], P < 0.001), and absolute lymphocyte count (1.41 [0.72] × 103/μL vs. 1.79 [0.68] × 103/μL, P < 0.001), and they had a significantly higher mean (SD) white blood cell count (10.4 [3.8] × 103/μL vs. 7.6 [2.3] × 103/μL, P < 0.001), absolute neutrophil count (7.8 [3.8] × 103/μL vs. 5.0 [2.5] × 103/μL, P < 0.001), and neutrophil count (74% [14%] vs. 64% [13%], P < 0.001). Among patients with unruptured AVMs, white blood cell count ≥6.4 × 103/μL and absolute neutrophil count ≥3.4 × 103/μL were associated with a favorable neurologic outcome, whereas hemoglobin level ≥13.4 g/dL was associated with an unfavorable outcome. Among patients with ruptured AVMs, hypertension was associated with a 3-fold increase in odds of a poor neurologic outcome.

CONCLUSIONS

Patients with ruptured and unruptured AVMs present with characteristic profiles of hematologic and inflammatory parameters evident in their admission blood work.

Current perspectives and trends in the treatment of brain arteriovenous malformations: a review and bibliometric analysis

Background

Currently, there is a lack of intuitive analysis regarding the development trend, main authors, and research hotspots in the field of cerebral arteriovenous malformation treatment, as well as a detailed elaboration of possible research hotspots.

Methods

A bibliometric analysis was conducted on data retrieved from the Web of Science core collection database between 2000 and 2022. The analysis was performed using R, VOSviewer, CiteSpace software, and an online bibliometric platform.

Results

A total of 1,356 articles were collected, and the number of publications has increased over time. The United States and the University of Pittsburgh are the most prolific countries and institutions in the field. The top three cited authors are Kondziolka D, Sheehan JP, and Lunsford LD. The Journal of Neurosurgery and Neurosurgery are two of the most influential journals in the field of brain arteriovenous malformation treatment research, with higher H-index, total citations, and number of publications. Furthermore, the analysis of keywords indicates that "aruba trial," "randomised trial," "microsurgery," "onyx embolization," and "Spetzler-Martin grade" may become research focal points. Additionally, this paper discusses the current research status, existing issues, and potential future research directions for the treatment of brain arteriovenous malformations.

Conclusion

This bibliometric study comprehensively analyses the publication trend of cerebral arteriovenous malformation treatment in the past 20 years. It covers the trend of international cooperation, publications, and research hotspots. This information provides an important reference for scholars to further study cerebral arteriovenous malformation.

The Role and Therapeutic Implications of Inflammation in the Pathogenesis of Brain Arteriovenous Malformations

Brain arteriovenous malformations (bAVMs) are focal vascular lesions composed of abnormal vascular channels without an intervening capillary network. As a result, high-pressure arterial blood shunts directly into the venous outflow system. These high-flow, low-resistance shunts are composed of dilated, tortuous, and fragile vessels, which are prone to rupture. BAVMs are a leading cause of hemorrhagic stroke in children and young adults. Current treatments for bAVMs are limited to surgery, embolization, and radiosurgery, although even these options are not viable for ~20% of AVM patients due to excessive risk. Critically, inflammation has been suggested to contribute to lesion progression. Here we summarize the current literature discussing the role of the immune system in bAVM pathogenesis and lesion progression, as well as the potential for targeting inflammation to prevent bAVM rupture and intracranial hemorrhage. We conclude by proposing that a dysfunctional endothelium, which harbors the somatic mutations that have been shown to give rise to sporadic bAVMs, may drive disease development and progression by altering the immune status of the brain.

Increased Matrix Metalloproteinase-1 Activation Enhances Disruption and Regression of k-RasV12-Expressing Arteriovenous Malformation-Like Vessels

This study sought to identify potential mechanisms by which k-RasV12-expressing endothelial cell (EC) tubes demonstrate an increased propensity to regress compared with controls. Activated k-Ras mutations play a role in a variety of pathological conditions, including arteriovenous malformations, which are prone to bleed, causing serious hemorrhagic complications. ECs expressing active k-RasV12 demonstrate markedly excessive lumen formation with widened and shortened tubes accompanied by reduced pericyte recruitment and basement membrane deposition, leading to deficient capillary network assembly. The current study showed that active k-Ras-expressing ECs secreted greater amounts of MMP-1 proenzyme compared with control ECs, and readily converted it to increased active MMP-1 levels through the action of plasmin or plasma kallikrein (generated from their added zymogens). Active MMP-1 degraded three-dimensional collagen matrices, leading to more rapid and extensive regression of the active k-Ras-expressing EC tubes, in conjunction with matrix contraction, compared with control ECs. Under conditions where pericytes protect control EC tubes from plasminogen- and MMP-1-dependent tube regression, this failed to occur with k-RasV12 ECs, due to reduced pericyte interactions. In summary, k-RasV12-expressing EC vessels showed an increased propensity to regress in response to serine proteinases through accentuated levels of active MMP-1, a novel pathogenic mechanism that may underlie hemorrhagic events associated with arteriovenous malformation lesions.

Green ecofriendly electrochemical sensing platform for the sensitive determination of doxycycline

The detection of pharmaceutical compounds in extremely low concentrations remains a challenge despite recent advancements in electrochemical sensing. In this study, a green hydrothermally synthesized nickel hydroxide-graphene hybrid material was used for the point-of-care determination of the antibiotic doxycycline (DOXY), which is a promising treatment for COVID-19 and other infections. The electrochemical sensor, based on a screen-printed electrode modified with the hybrid material, was able to detect DOXY in the range of 5.1 × 10^-8 to 1.0 × 10^-4 M, with a low detection limit of 9.6 × 10^-9 M. This approach paves the way for eco-friendly and sustainable methods of nanomaterial synthesis for electrochemical analyses, particularly in point-of-care drug monitoring, and has the potential to improve access to testing platforms.

Arteriovenous Malformations: An Update on Models and Therapeutic Targets

Arteriovenous malformations (AVMs) are an anomaly of the vascular system where feeding arteries are directly connected to the venous drainage network. While AVMs can arise anywhere in the body and have been described in most tissues, brain AVMs are of significant concern because of the risk of hemorrhage which carries significant morbidity and mortality. The prevalence of AVM's and the mechanisms underlying their formation are not well understood. For this reason, patients who undergo treatment for symptomatic AVM's remain at increased risk of subsequent bleeds and adverse outcomes. The cerebrovascular network is delicate and novel animal models continue to provide insight into its dynamics in the context of AVM's. As the molecular players in the formation of familial and sporadic AVM's are better understood, novel therapeutic approaches have been developed to mitigate their associated risks. Here we discuss the current literature surrounding AVM's including the development of models and therapeutic targets which are currently being investigated.

Target ischemic stroke model creation method using photoacoustic microscopy with simultaneous vessel monitoring and dynamic photothrombosis induction

The ischemic stroke animal model evaluates the efficacy of reperfusion and neuroprotective strategies for ischemic injuries. Various conventional methods have been reported to induce the ischemic models; however, controlling specific neurological deficits, mortality rates, and the extent of the infarction is difficult as the size of the affected region is not precisely controlled. In this paper, we report a single laser-based localized target ischemic stroke model development method by simultaneous vessel monitoring and photothrombosis induction using photoacoustic microscopy (PAM), which has minimized the infarct size at precise location with high reproducibility. The proposed method has significantly reduced the infarcted region by illuminating the precise localization. The reproducibility and validity of suggested method have been demonstrated through repeated experiments and histological analyses. These results demonstrate that our method can provide the ischemic stroke model closest to the clinical pathology for brain ischemia research from inducement, occurrence mechanisms to the recovery process.

Endovascular treatment in the multimodality management of brain arteriovenous malformations: report of the Society of NeuroInterventional Surgery Standards and Guidelines Committee

BACKGROUND

The purpose of this review is to summarize the data available for the role of angiography and embolization in the comprehensive multidisciplinary management of brain arteriovenous malformations (AVMs METHODS: We performed a structured literature review for studies examining the indications, efficacy, and outcomes for patients undergoing endovascular therapy in the context of brain AVM management. We graded the quality of the evidence. Recommendations were arrived at through a consensus conference of the authors, then with additional input from the full Society of NeuroInterventional Surgery (SNIS) Standards and Guidelines Committee and the SNIS Board of Directors.

RESULTS

The multidisciplinary evaluation and treatment of brain AVMs continues to evolve. Recommendations include: (1) Digital subtraction catheter cerebral angiography (DSA)-including 2D, 3D, and reformatted cross-sectional views when appropriate-is recommended in the pre-treatment assessment of cerebral AVMs. (I, B-NR) . (2) It is recommended that endovascular embolization of cerebral arteriovenous malformations be performed in the context of a complete multidisciplinary treatment plan aiming for obliteration of the AVM and cure. (I, B-NR) . (3) Embolization of brain AVMs before surgical resection can be useful to reduce intraoperative blood loss, morbidity, and surgical complexity. (IIa, B-NR) . (4) The role of primary curative embolization of cerebral arteriovenous malformations is uncertain, particularly as compared with microsurgery and radiosurgery with or without adjunctive embolization. Further research is needed, particularly with regard to risk for AVM recurrence. (III equivocal, C-LD) . (5) Targeted embolization of high-risk features of ruptured brain AVMs may be considered to reduce the risk for recurrent hemorrhage. (IIb, C-LD) . (6) Palliative embolization may be useful to treat symptomatic AVMs in which curative therapy is otherwise not possible. (IIb, B-NR) . (7) The role of AVM embolization as an adjunct to radiosurgery is not well-established. Further research is needed. (III equivocal, C-LD) . (8) Imaging follow-up after apparent cure of brain AVMs is recommended to assess for recurrence. Although non-invasive imaging may be used for longitudinal follow-up, DSA remains the gold standard for residual or recurrent AVM detection in patients with concerning imaging and/or clinical findings. (I, C-LD) . (9) Improved national and international reporting of patients of all ages with brain AVMs, their treatments, side effects from treatment, and their long-term outcomes would enhance the ability to perform clinical trials and improve the rigor of research into this rare condition. (I, C-EO) .

CONCLUSIONS

Although the quality of evidence is lower than for more common conditions subjected to multiple randomized controlled trials, endovascular therapy has an important role in the management of brain AVMs. Prospective studies are needed to strengthen the data supporting these recommendations.

State of the Art and Future Direction in Diagnosis, Molecular Biology, Genetics, and Treatment of Brain Arteriovenous Malformations

Brain arteriovenous malformations (bAVMs) are uncommon and represent a heterogeneous group of lesions. Although these 2 facts have delayed research on this topic, knowledge about the pathophysiology, diagnosis, and treatment of bAVMs has evolved in recent years. We conducted a review of the literature to update the knowledge about diagnosis, molecular biology, genetic, pathology, and treatment by searching for the following terms: "Epidemiology AND Natural History," "risk of hemorrhage," "intracranial hemorrhage," "diagnosis," "angiogenesis," "molecular genetics," "VEGF," "KRAS," "radiosurgery," "endovascular," "microsurgery," or "surgical resection." Our understanding of bAVMs has significantly evolved in recent years. The latest investigations have helped in defining some molecular pathways involved in the pathology of bAVM. Although there is still more to learn and discover, describing these pathways will allow the creation of targeted treatments that could improve the prognosis of patients with bAVMs.

Metalloproteinases and their inhibitors in neurological disease

Matrix metalloproteinases (MMPs) are a group of endopeptidases that degrade the extracellular matrix and are responsible for many physiological and pathological processes. We aim to review the MMP inhibition from a clinical perspective and its possible therapeutic use in the future. MMPs play a role in various neurodegenerative and cerebrovascular diseases such as large artery atherosclerosis and ischemic stroke; for example, MMPs increase blood-brain barrier permeability favoring neuroinflammation. Synthetic MMPs inhibitors have been tested mostly in oncological trials and failed to demonstrate efficacy; some of them were discontinued because of the severe adverse reactions. Tetracyclines, in submicrobial doses, act as an MMP inhibitor, although tetracyclines have not yet been proven effective in several neurological conditions in which they were tested against placebo; it is uncertain whether there may be a use for tetracyclines in cerebrovascular disease, as a neuroprotective agent or in dolichoectasia.

Review of treatment and therapeutic targets in brain arteriovenous malformation

Brain arteriovenous malformations (bAVM) are an important cause of intracranial hemorrhage (ICH), especially in younger patients. The pathogenesis of bAVM are largely unknown. Current understanding of bAVM etiology is based on studying genetic syndromes, animal models, and surgically resected specimens from patients. The identification of activating somatic mutations in the Kirsten rat sarcoma viral oncogene homologue (KRAS) gene and other mitogen-activated protein kinase (MAPK) pathway genes has opened up new avenues for bAVM study, leading to a paradigm shift to search for somatic, de novo mutations in sporadic bAVMs instead of focusing on inherited genetic mutations. Through the development of new models and understanding of pathways involved in maintaining normal vascular structure and functions, promising therapeutic targets have been identified and safety and efficacy studies are underway in animal models and in patients. The goal of this paper is to provide a thorough review or current diagnostic and treatment tools, known genes and key pathways involved in bAVM pathogenesis to summarize current treatment options and potential therapeutic targets uncovered by recent discoveries.

Molecular Biomarkers and Drug Targets in Brain Arteriovenous and Cavernous Malformations: Where Are We?

Vascular malformations of the brain (VMB) comprise abnormal development of blood vessels. A small fraction of VMBs causes hemorrhages with neurological morbidity and risk of mortality in patients. Most often, they are symptomatically silent and are detected at advanced stages of disease progression. The most common forms of VMBs are arteriovenous and cavernous malformations in the brain. Radiopathological features of these diseases are complex with high phenotypic variability. Early detection of these malformations followed by preclusion of severe neurological deficits such as hemorrhage and stroke is crucial in the clinical management of patients with VMBs. The technological advances in high-throughput omics platforms have currently infused a zest in translational research in VMBs. Besides finding novel biomarkers and therapeutic targets, these studies have withal contributed significantly to the understanding of the etiopathogenesis of VMBs. Here we discuss the recent advances in predictive and prognostic biomarker research in sporadic and familial arteriovenous malformations as well as cerebral cavernous malformations. Furthermore, we analyze the clinical applicability of protein and noncoding RNA-based molecular-targeted therapies which may have a potentially key role in disease management.

Pathogenesis and therapy of arteriovenous malformations: A case report and narrative review

Arteriovenous malformations (AVMs) are abnormal communications between arteries and veins that lack intervening capillary beds. They have been described in almost every organ in the body, emerging sporadically or as part of well-described syndromes. Hereditary hemorrhagic telangiectasia (HHT) is a rare, progressive, and lifelong disease characterized by AVMs and recurrent hemorrhaging. In the last 2 decades, significant advances have been made in understanding the pathogenesis of this condition. The accumulation of knowledge has led to a natural evolution of therapy, from open surgery to endovascular procedures, and now to a role for medications in certain AVMs. Here, we review a case of HHT and describe the most up-to-date clinical practice, including diagnosis of HHT, subtypes of HHT, and medical therapy.

Proof-of-concept single-arm trial of bevacizumab therapy for brain arteriovenous malformation

Brain arteriovenous malformations (bAVMs) are relatively rare, although their potential for secondary intracranial haemorrhage (ICH) makes their diagnosis and management essential to the community. Currently, invasive therapies (surgical resection, stereotactic radiosurgery and endovascular embolisation) are the only interventions that offer a reduction in ICH risk. There is no designated medical therapy for bAVM, although there is growing animal and human evidence supporting a role for bevacizumab to reduce the size of AVMs. In this single-arm pilot study, two patients with large bAVMs (deemed unresectable by an interdisciplinary team) received bevacizumab 5 mg/kg every 2 weeks for 12 weeks. Due to limitations of external funding, the intended sample size of 10 participants was not reached. Primary outcome measure was change in bAVM volume from baseline at 26 and 52 weeks. No change in bAVM volume was observed 26 or 52 weeks after bevacizumab treatment. No clinically important adverse events were observed during the 52-week study period. There were no observed instances of ICH. Sera vascular endothelial growth factor levels were reduced at 26 weeks and returned to baseline at 52 weeks. This pilot study is the first to test bevacizumab for patients with bAVMs. Bevacizumab therapy was well tolerated in both subjects. No radiographic changes were observed over the 52-week study period. Subsequent larger clinical trials are in order to assess for dose-dependent efficacy and rarer adverse drug effects. Trial registration number: NCT02314377.

An Update on Medications for Brain Arteriovenous Malformations

Despite a variety of treatment options for brain arteriovenous malformations (bAVMs), many lesions remain challenging to treat and present significant ongoing risk for hemorrhage. In Vitro investigations have recently led to a greater understanding of the formation, growth, and rupture of bAVMs. This has, in turn, led to the development of therapeutic targets for medications for bAVMs, some of which have begun testing in clinical trials in humans. These include bevacizumab, targeting the vascular endothelial growth factor driven angiogenic pathway; thalidomide or lenalidomide, targeting blood-brain barrier impairment; and doxycycline, targeting matrix metalloproteinase overexpression. A variety of other medications appear promising but either requires adaptation from other disease states or development from early bench studies into the clinical realm. This review aims to provide an overview of the current state of development of medications targeting bAVMs and to highlight their likely applications in the future.

Neurovascular inflammation in the pathogenesis of brain arteriovenous malformations

Brain arteriovenous malformations (bAVM) arise as congenital or sporadic focal lesions with a significant risk for intracerebral hemorrhage (ICH). A wide range of interindividual differences is present in the onset, progression, and severity of bAVM. A growing body of gene expression and polymorphism-based research studies support the involvement of localized inflammation in bAVM disease progression and rupture. In this review article, we analyze the altered responses of neural, vascular, and immune cell types that contribute to the inflammatory process, which exacerbates the pathophysiological progression of vascular dysmorphogenesis in bAVM lesions. The cumulative effect of inflammation in bAVM development is orchestrated by various genetic moderators and inflammatory mediators. We also discuss the potential therapies for the treatment of brain AVM by targeting the inflammatory processes and mediators. Elucidating the precise role of inflammation in the bAVM growth and hemorrhage would open novel avenues for noninvasive and effectual causal therapy that may complement the current therapeutic strategies.

The Role of Matrix Metalloproteinase-3 in the Doxycycline Attenuation of Intracranial Venous Hypertension-Induced Angiogenesis

BACKGROUND

The molecular mechanism of brain arteriovenous malformation (BAVM) is largely unknown. Intracranial venous hypertension (VH) may enhance focal angiogenesis and promote BAVM development and progression. A rat VH model effectively simulates the hemodynamic microenvironment of this disease.

OBJECTIVE

To explore the effect of doxycycline in VH-related angiogenesis, as well as the role of matrix metalloproteinase-3 (MMP-3) and other molecular factors.

METHODS

A rat VH model was generated by common carotid artery and distal external jugular vein anastomosis. Microvessel density (MVD) in the perisinus area and expression of MMP-3/2/9, VEGF, TIMP-1, TGF-β, and HIF-1α were examined, with and without daily doxycycline treatment for 4 wk. The effects of doxycycline were verified in Vitro using human brain microvascular endothelial cells (HBMECs). MMP-3 overexpression or knockdown in HBMECs was used to confirm the role of MMP-3 in cell functions.

RESULTS

MVD in the perisinus cortex was greatly increased after VH. Doxycycline decreased MVD, suppressed MMP-3 overexpression, and reduced VEGF, TGF-β, and TIMP-1 levels compared with the controls (P < .05). In Vitro, doxycycline decreased HBMEC migration, tube formation, and the mRNA, protein, and enzymatic activity levels of MMP-3. MMP-3 overexpression in HBMECs promoted migration, while knockdown of MMP-3 significantly attenuated proliferation, migration, and tube formation (P < .05).

CONCLUSION

Our findings indicate that MMP-3 plays an important role in VH-related angiogenesis and the promotion of vascular remodeling. Suppression of MMP-3 overexpression by doxycycline may provide a potential strategy for inhibiting BAVM development.

The Efficacy of Systemic Doxycycline Administration as an Inhibitor of Intimal Hyperplasia after Balloon Angioplasty Arterial Injury

BACKGROUND

Intimal hyperplasia (IH) is the most common indicator for secondary intervention in peripheral vascular disease. Matrix metalloproteinases (MMPs) play a role in IH development due to their degradation of the extracellular matrix. Doxycycline (Doxy), a member of the tetracycline family of antibiotics, is a potent MMP inhibitor. We have previously shown that Doxy inhibits MMP activity and vascular smooth muscle cell migration in vitro. We hypothesized that Doxy would decrease MMP activity in vivo and inhibit the development of IH in a rodent model of vascular injury.

METHODS AND RESULTS

Doxy (400 mg/pellet) was delivered by a slow-release pellet implanted 3 days prior to or at the time of balloon angioplasty (BA) of the common carotid artery in female rats. At 14 days post-BA, intima-to-media (I:M) ratios were 0.77 ± 0.21 and 1.04 ± 0.32 in the Doxy treated groups, respectively, compared to 1.25 ± 0.26 in the control group (P = not significant; n = 3). Additionally, the tested dose of Doxy in either group had no inhibitory effect on membrane type 1-MMP or MMP-2 tissue levels, as measured by immunohistochemistry, or on systemic levels of MMP, as measured by total MMP serum levels using enzyme-linked immunosorbent assay. At 14 days post-BA, VSMC proliferation in the injured artery was increased to Doxy treatment prior to and at the time of surgery (23.5 ± 3.4 and 27.2 ± 3.9%, respectively), compared to control (11.4 ± 0.4%; n = 3), as measured by proliferating cellular nuclear antigen immunostaining.

CONCLUSIONS

In our in vivo model of vascular injury, systemic Doxy administration prior to or at the time of vascular injury does not significantly hinder the progression of IH development. Additional doses and routes of administration could be examined in order to correlate therapeutic serum levels of Doxy with effective MMP inhibition in serum and arterial tissue. However, alternative drug delivery systems are needed in order to optimize therapeutic administration of targeted MMP inhibitors for the prevention of IH development.

Oral doxycycline for the prevention of postoperative trachomatous trichiasis in Ethiopia: a randomised, double-blind, placebo-controlled trial

BACKGROUND

Trachomatous trichiasis is treated surgically to prevent sight loss. Unfavourable surgical outcomes remain a major challenge. We investigated the hypothesis that doxycycline might reduce the risk of postoperative trichiasis following surgery in patients with trachomatous trichiasis through anti-matrix metalloproteinase and anti-inflammatory activity.

METHODS

In this randomised, double-blind, placebo-controlled trial, adults (aged >18 years) with upper lid trachomatous trichiasis in association with tarsal conjunctive scarring were recruited through community-based screening and surgical outreach campaigns in Ethiopia. Individuals who had previously had eyelid surgery were excluded. Participants were randomly assigned (1:1), with random block sizes of four or six, to receive oral doxycycline (100 mg once a day) or placebo for 28 days immediately after trichiasis surgery. Randomisation was stratified by surgeon. Patients, investigators, surgeons, and all other study team members were masked to study group allocation and treatment. Participants were examined at 10 days, and 1, 6, and 12 months after surgery. The primary outcome was the cumulative proportion of individuals who developed postoperative trichiasis by 12 months. Primary analyses were done in all participants who attended at least one of the four follow-up assessments. Safety analyses were done in all participants who attended either the 10 day or 1 month follow-up assessments. This trial is registered with the Pan African Clinical Trials Registry, number PACTR201512001370307.

FINDINGS

Between Dec 21, 2015, and April 6, 2016, 1000 patients with trichiasis were enrolled and randomly assigned to treatment (499 patients to doxycycline, 501 patients to placebo). All but one participant attended at least one follow-up assessment. Thus, 999 participants were assessed for the primary outcome: 498 in the doxycycline group and 501 in the placebo group. By month 12, 58 (12%) of 498 patients in the doxycycline group and 62 (12%) of 501 patients in the placebo group had developed postoperative trichiasis (adjusted odds ratio 0·91, 95% CI 0·61 to 1·34, p=0·63), with a risk difference of -0·5% (-4·5% to 3·5%). Significantly more patients in the doxycycline group had an adverse event than in the placebo group (18 [4%] of 498 vs six [1%] of 501; odds ratio 3·09, 95% CI 1·21-7·84; p=0·02). The most frequent adverse events in the doxycycline group were gastritis symptoms (n=9), constipation (n=4), and diarrhoea (n=4).

INTERPRETATION

Doxycycline did not reduce the risk of postoperative trichiasis and is therefore not indicated for the improvement of outcomes following trachomatous trichiasis surgery. Surgical programmes should continue to make efforts to strengthen surgical training and supervision to improve outcomes.

FUNDING

The Wellcome Trust.

Effect of pomegranate extracts on brain antioxidant markers and cholinesterase activity in high fat-high fructose diet induced obesity in rat model

Background

To investigate beneficial effects of Pomegranate seeds oil (PSO), leaves (PL), juice (PJ) and (PP) on brain cholinesterase activity, brain oxidative stress and lipid profile in high-fat-high fructose diet (HFD) induced-obese rat.

Methods

In vitro and in vivo cholinesterase activity, brain oxidative status, body and brain weight and plasma lipid profile were measured in control rats, HFD-fed rats and HFD-fed rats treated by PSO, PL, PJ and PP.

Results

In vitro study showed that PSO, PL, PP, PJ inhibited cholinesterase activity in dose dependant manner. PL extract displayed the highest inhibitory activity by IC50 of 151.85 mg/ml. For in vivo study, HFD regime induced a significant increase of cholinesterase activity in brain by 17.4% as compared to normal rats. However, the administration of PSO, PL, PJ and PP to HDF-rats decreased cholinesterase activity in brain respectively by 15.48%, 6.4%, 20% and 18.7% as compared to untreated HFD-rats. Moreover, HFD regime caused significant increase in brain stress, brain and body weight, and lipid profile disorders in blood. Furthermore, PSO, PL, PJ and PP modulated lipid profile in blood and prevented accumulation of lipid in brain and body evidenced by the decrease of their weights as compared to untreated HFD-rats. In addition administration of these extract protected brain from stress oxidant, evidenced by the decrease of malondialdehyde (MDA) and Protein carbonylation (PC) levels and the increase in superoxide dismutase (SOD) and glutathione peroxidase (GPx) levels.

Conclusion

These findings highlight the neuroprotective effects of pomegranate extracts and one of mechanisms is the inhibition of cholinesterase and the stimulation of antioxidant capacity.

Multimodality management and outcomes of brain arterio-venous malformations (AVMs) in children: personal experience and review of the literature, with specific emphasis on age at first AVM bleed

PURPOSE

The purpose of this paper is to study the presentation and analyse the results of multimodality treatment of brain arterio-venous malformations (AVMs) in children at our centre and review age at first AVM rupture in the literature.

METHODS

Of 52 patients aged <18 years, 47 with brain AVMs (27 males and 20 females) aged 4-17 years (mean 12.2) were retrospectively reviewed. PubMed search revealed five additional studies including 267 patients where the prevalence of age-related AVMs rupture was analysed.

RESULTS

In our study, 37 patients had bled, 9 were symptomatic without haemorrhage and 1 was incidental. Spetzler-Martin score distribution was 5 cases grade I, 18 grade II, 21 grade III and 3 grade IV. Appropriate imaging was performed, either CT/MRI angiogram only (in emergency cases) or catheter angiogram, prior to definitive treatment. There were 40 supratentorial and 7 infratentorial AVMs. Twenty-nine patients had microsurgery alone and 9 patients were treated by radiosurgery only. Three patients were embolised, all followed by radiosurgery, with one requiring surgery too, while 4 patients had combined surgery and radiosurgery. One patient is awaiting radiosurgery while another was not treated. Good outcomes, classified as modified Rankin score (mRS) 0-2 improved significantly after intervention to 89.4% from 38.3% pre-treatment (p value <0.0001). Angiography confirmed 96.6% obliteration after first planned operation. Repeat cerebral angiogram around age 18 was negative in all previously cured patients. Reviewing the literature, 82.0% (95% CI = [77-87]; N = 267) of children diagnosed with brain AVMs (mean age 11.4 ± 0.4) presented with a bleed in the last 22 years. Males significantly outnumbered females (136 vs 84) (p < 0.001). Ninety-five patients underwent surgical intervention alone when compared to other treatment modalities (p < 0.001).

CONCLUSIONS

Microsurgical excision of surgically accessible intracranial AVMs remains the primary treatment option with very good outcomes. A significant number of patients' AVMs ruptured around puberty; therefore, understanding the pathophysiology of AVM instability at this age may aid future therapy.

Effects of Neighborhood Characteristics on Length of Inpatient Stay: Findings from the U.S. National Data

Using a nationally representative U.S. sample, this study examined the extent to which neighborhood characteristics affected length of inpatient stay (LOS) in the United States. Data were obtained from the 2012 Area Health Resource Files. A total of 3,148 U.S. counties were included in the study. Generalized linear models and the geographically weighted regression model were used to examine the extent to which neighborhood characteristics affected LOS and its spatial variation. Exploratory spatial data analysis was also conducted to examine the geographic patterns in LOS. Hospital bed capacity was found to be the strongest predictor of LOS. Counties with a lower poverty rate, a lower uninsured rate, a higher proportion of female residents, a higher proportion of residents living in urban areas, and more diverse racial groups had a longer LOS. Significant spatial clustering pattern of LOS was also found. Findings suggest that social work professionals should be aware of spatial disparity in health care resources and develop ways of providing equitable health care for vulnerable populations in socioeconomically disadvantaged neighborhoods.

On cognitive ecology and the environmental factors that promote Alzheimer disease: lessons from Octodon degus (Rodentia: Octodontidae)

Cognitive ecologist posits that the more efficiently an animal uses information from the biotic and abiotic environment, the more adaptive are its cognitive abilities. Nevertheless, this approach does not test for natural neurodegenerative processes under field or experimental conditions, which may recover animals information processing and decision making and may explain, mechanistically, maladaptive behaviors. Here, we call for integrative approaches to explain the relationship between ultimate and proximate mechanisms behind social behavior. We highlight the importance of using the endemic caviomorph rodent Octodon degus as a valuable natural model for mechanistic studies of social behavior and to explain how physical environments can shape social experiences that might influence impaired cognitive abilities and the onset and progression of neurodegenerative disorders such as Alzheimer disease. We consequently suggest neuroecological approaches to examine how key elements of the environment may affect neural and cognitive mechanisms associated with learning, memory processes and brain structures involved in social behavior. We propose the following three core objectives of a program comprising interdisciplinary research in O. degus, namely: (1) to determine whether diet types provided after weaning can lead to cognitive impairment associated with spatial memory, learning and predisposing to develop Alzheimer disease in younger ages; (2) to examine if early life social experience has long term effects on behavior and cognitive responses and risk for development Alzheimer disease in later life and (3) To determine if an increase of social interactions in adult degu reared in different degree of social stressful conditions alter their behavior and cognitive responses.

Increased expression of angiogenic factors in cultured human brain arteriovenous malformation endothelial cells

To compare the mRNA level of angiogenic factor vascular endothelial growth factor (VEGF), matrix metalloproteinases (MMP)-2, and MMP-9 in cultured human brain arteriovenous malformation (AVM) endothelial cells (ECs) and normal brain endothelial cells (BECs). Tissue explants both from deformed vessels of AVM and normal microvessel were put into culture for endothelial cells. After the monolayer adherent ECs reached confluence, they were tested with endothelial specific marker CD34 and von Willebrand factor (vWF) by immunochemical assay. mRNA levels of VEGF-A, MMP-2, and MMP-9 in AVM endothelial cells (AVMECs) and BECs were measured by PCR. Immunostaining confirmed that more than 95 % of the cultured cells were CD34 (Fig. 1b) and/or vWF positive. Expression levels of VEGF-A and MMP-2 mRNAs were significantly higher in AVMECs than in BECs. The MMP-9 level was also increased in AVMECs, but the difference was not statistically significant. Vascular tissue explants adherent method is a better approach for isolation and culture of AVMECs. Cultured AVMECs expressed higher angiogenic factors (VEGF, MMP-2) than the controlled BECs, implicating angiogenesis plays an important role in the pathogenesis of AVM.

A comparative study on hypoglycemic properties, lipid profile and bioactive components of hydro-alcoholic extracts of cooked and raw Brassica napus

Introduction: Many plants with anti-oxidant properties proved to be effective on diabetes treatment. Brassica napus (turnip) is an anti-oxidant plant consumed raw or cooked. In this study, we examined and compared hypoglycemic and hypolipidemic properties of raw and cooked Brassica napus in diabetic rats. Objectives: Due to measuring bioactive component of Brassica napus as a rich source of flavonoid we investigate the hypoglycemic properties in raw and cooked type. Material and Methods: For this experimental study, 50 male Wistar rats weighing 200-250 g were designated into five groups of 10 consist of control, diabetic control, diabetic cooked turnip, diabetic raw turnip, and diabetic glibenclamide. The alloxan-induced diabetic rats received extracts orally for 4 weeks. Then, the serum biochemical factors were measured and compared statisticaly by analysis of variance (ANOVA) test. Results: Serum glucose, triglyceride (TG), cholesterol, and low density lipoprotein cholesterol (LDL-C) were significantly decreased in cooked and raw turnip rats compared to control ones. Cooked and raw Brassica napus extracts both helped high density lipoprotein cholesterol (HDL-C) increase; cooked turnip competency was superior in view of cholesterol and LDL-C decrease as well as HDL-C increase (P < 0.05). The mean difference in glucose and TG decrease was not significant between diabetic cooked turnip and diabetic raw turnip rats. Conclusion: Improving the blood glucose and lipid levels diabetic rats, in this study, may indicate that both raw and cooked Brassica napus extracts (especially the cooked one) may be beneficial in diabetic patients.

Brain arteriovenous malformations

An arteriovenous malformation is a tangle of dysplastic vessels (nidus) fed by arteries and drained by veins without intervening capillaries, forming a high-flow, low-resistance shunt between the arterial and venous systems. Arteriovenous malformations in the brain have a low estimated prevalence but are an important cause of intracerebral haemorrhage in young adults. For previously unruptured malformations, bleeding rates are approximately 1% per year. Once ruptured, the subsequent risk increases fivefold, depending on associated aneurysms, deep locations, deep drainage and increasing age. Recent findings from novel animal models and genetic studies suggest that arteriovenous malformations, which were long considered congenital, arise from aberrant vasculogenesis, genetic mutations and/or angiogenesis after injury. The phenotypical characteristics of arteriovenous malformations differ among age groups, with fistulous lesions in children and nidal lesions in adults. Diagnosis mainly involves imaging techniques, including CT, MRI and angiography. Management includes observation, microsurgical resection, endovascular embolization and stereotactic radiosurgery, alone or in any combination. There is little consensus on how to manage patients with unruptured malformations; recent studies have shown that patients managed medically fared better than those with intervention at short-term follow-up. By contrast, interventional treatment is preferred following a ruptured malformation to prevent rehaemorrhage. Management continues to evolve as new mechanistic discoveries and reliable animal models raise the possibility of developing drugs that might prevent the formation of arteriovenous malformations, induce obliteration and/or stabilize vessels to reduce rupture risk. For an illustrated summary of this Primer, visit: http://go.nature.com/TMoAdn.

Molecular and cellular biology of cerebral arteriovenous malformations: a review of current concepts and future trends in treatment

OBJECT

Arteriovenous malformations (AVMs) are classically described as congenital static lesions. However, in addition to rupturing, AVMs can undergo growth, remodeling, and regression. These phenomena are directly related to cellular, molecular, and physiological processes. Understanding these relationships is essential to direct future diagnostic and therapeutic strategies. The authors performed a search of the contemporary literature to review current information regarding the molecular and cellular biology of AVMs and how this biology will impact their potential future management.

METHODS

A PubMed search was performed using the key words "genetic," "molecular," "brain," "cerebral," "arteriovenous," "malformation," "rupture," "management," "embolization," and "radiosurgery." Only English-language papers were considered. The reference lists of all papers selected for full-text assessment were reviewed.

RESULTS

Current concepts in genetic polymorphisms, growth factors, angiopoietins, apoptosis, endothelial cells, pathophysiology, clinical syndromes, medical treatment (including tetracycline and microRNA-18a), radiation therapy, endovascular embolization, and surgical treatment as they apply to AVMs are discussed.

CONCLUSIONS

Understanding the complex cellular biology, physiology, hemodynamics, and flow-related phenomena of AVMs is critical for defining and predicting their behavior, developing novel drug treatments, and improving endovascular and surgical therapies.

Modeling of in hospital mortality determinants in myocardial infarction patients, with and without type 2 diabetes, undergoing pharmaco-invasive strategy: the first national report using two approaches in Iran

This study was conducted to compare the characteristics of patients, with and without diabetes mellitus, presenting with myocardial infarction (MI) and treated with coronary artery bypass grafting (CABG), percutaneous coronary intervention (PCI), or thrombolytic therapy. Factors related to mortality due to MI in Iran were also determined. This study was a prospective analysis. To analyze the data, Stata software (chi square, t test, Cox and logistic regression) was used. Participants were patients hospitalized for MI for the first time in 540 hospitals from April, 2012 to March, 2013. Out of 20,750 patients with MI, 461 2 (22.3%) had type 2 diabetes. MI case fatality rate was 13.22% (95%CI: 12.24-14.19) and 11.78% (95%CI: 11.28-12.27) in patients with and without diabetes, respectively. The rates of CABG, PCI, and thrombolytic therapy use were 4.2%, 8%, and 58% in patients with diabetes, and 2.1%, 6.5%, and 55% in patients without diabetes. The odds ratio of mortality for ST segment elevation myocardial infarction (STEMI) and chest pain resistant to treatment was, respectively, 6.3 and 2.8 in those with diabetes, and 3.9 and 3.7 in patients without diabetes. The hazard ratio of mortality for gender, education, smoking, left bundle branch block, PCI, and type of MI was different between the two groups (P<0.05). Characteristics of patients dying post MI were different in those with or without diabetes mellitus. Although use of CABG, PCI, and thrombolytic therapy was more frequent in patients with diabetes than without, mortality was higher in diabetes patients.

Biology of cerebral arteriovenous malformations with a focus on inflammation

Cerebral arteriovenous malformations (AVMs) entail a significant risk of intracerebral hemorrhage owing to the direct shunting of arterial blood into the venous vasculature without the dissipation of the arterial blood pressure. The mechanisms involved in the growth, progression and rupture of AVMs are not clearly understood, but a number of studies point to inflammation as a major contributor to their pathogenesis. The upregulation of proinflammatory cytokines induces the overexpression of cell adhesion molecules in AVM endothelial cells, resulting in enhanced recruitment of leukocytes. The increased leukocyte-derived release of metalloproteinase-9 is known to damage AVM walls and lead to rupture. Inflammation is also involved in altering the AVM angioarchitecture via the upregulation of angiogenic factors that affect endothelial cell proliferation, migration and apoptosis. The effects of inflammation on AVM pathogenesis are potentiated by certain single-nucleotide polymorphisms in the genes of proinflammatory cytokines, increasing their protein levels in the AVM tissue. Furthermore, studies on metalloproteinase-9 inhibitors and on the involvement of Notch signaling in AVMs provide promising data for a potential basis for pharmacological treatment of AVMs. Potential therapeutic targets and areas requiring further investigation are highlighted.

Brain AVMs: an endovascular, surgical, and radiosurgical update

Brain arteriovenous malformations (bAVMs) are complex vascular lesions. Despite multiple studies, several classifications, and a great interest of the scientific community, case selection in AVM patients remains challenging. During the last few years, tremendous advancements widened therapeutic options and improved outcomes spreading indications for patients harboring lesions deemed inoperable in the past. Anatomical and biological case specific features, and natural history with a focus on presenting symptoms should be evaluated case by case and always kept in mind while planning a therapeutic management for a bAVMs. A multidisciplinary approach is strongly recommended when dealing with bAVMs and should involve physicians expertise in this kind of challenging lesions. The goal of this paper is to provide a focused review of the most recent acquisitions and therapeutic strategies regarding surgical, endovascular, and radiosurgical treatment.

[Doxycycline or how to create new with the old?]

Tetracyclines are broad-spectrum antibiotics that interfere with protein synthesis. They were first widely prescribed by dermatologists in the early 1950s in the treatment of acne. More recently, their biological actions on inflammation, proteolysis, angiogenesis, apoptosis, metal chelation, ionophoresis, and bone metabolism were studied. Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes that degrade components of the extracellular matrix (ECM). MMPs have direct or indirect effects on the vascular endothelium and the vascular relaxation/contraction system. The therapeutic effects of tetracyclines and analogues were studied in rosacea, bullous dermatoses, neutrophilic diseases, pyoderma gangrenosum, sarcoidosis, aortic aneurysms, cancer metastasis, periodontitis and autoimmune diseases autoimmune diseases such as rheumatoid arthritis and scleroderma. In addition, downregulation of MMP using doxycycline could be beneficial in reducing vascular dysfunction mediated by MMPs and progressive damage of the vascular wall. We review the nonantibiotic properties of doxycycline and its potential clinical applications.

Brain arteriovenous malformation modeling, pathogenesis, and novel therapeutic targets

Patients harboring brain arteriovenous malformation (bAVM) are at life-threatening risk of rupture and intracranial hemorrhage (ICH). The pathogenesis of bAVM has not been completely understood. Current treatment options are invasive, and ≈ 20 % of patients are not offered interventional therapy because of excessive treatment risk. There are no specific medical therapies to treat bAVMs. The lack of validated animal models has been an obstacle for testing hypotheses of bAVM pathogenesis and testing new therapies. In this review, we summarize bAVM model development and bAVM pathogenesis and potential therapeutic targets that have been identified during model development.

Advances in Radiosurgery for Arteriovenous Malformations of the Brain

Arteriovenous malformations of the brain are a considerable source of morbidity and mortality for patients who harbor them. Although our understanding of this disease has improved, it remains in evolution. Advances in our ability to treat these malformations and the modes by which we address them have also improved substantially. However, the variety of patient clinical and disease scenarios often leads us into challenging and complex management algorithms as we balance the risks of treatment against the natural history of the disease. The goal of this article is to provide a focused review of the natural history of cerebral arteriovenous malformations, to examine the role of stereotactic radiosurgery, to discuss the role of endovascular therapy as it relates to stereotactic radiosurgery, and to look toward future advances.

Doxycycline prevents matrix remodeling and contraction by trichiasis-derived conjunctival fibroblasts

PURPOSE

Trachoma is a conjunctival scarring disease, which is the leading infectious cause of blindness worldwide. Elimination of blinding trachoma is being held back by the high rate of trichiasis recurrence following surgery. There is currently no treatment available to suppress the profibrotic state and reduce recurrence. Although the mechanisms underlying trichiasis development are unknown, the profibrotic phenotype has been linked to matrix metalloproteinase (MMP) expression. Doxycycline, a well-known tetracycline antibiotic, can act as a broad MMP inhibitor and has showed some success in preventing fibrosis in various clinical contexts. The purpose of this work was to assess the antiscarring properties of doxycycline in an in vitro model of trichiasis fibroblast-mediated tissue contraction.

METHODS

Primary cultures of fibroblasts were established from conjunctival samples obtained from normal donors or during surgery for trachomatous trichiasis. The effect of doxycycline on matrix contraction was investigated in our standard collagen gel contraction model. Cell morphology and matrix integrity were assessed using confocal reflection microscopy. Quantitative real time polymerase chain reaction and a FRET-based assay were used to measure MMP expression and activity, respectively.

RESULTS

Doxycycline treatment successfully suppressed the contractile phenotype of trichiasis fibroblasts, matrix degradation, and significantly altered the expression of MMP1, MMP9, and MMP12 associated with the profibrotic phenotype.

CONCLUSIONS

In view of the results presented here and the wider use of doxycycline in clinical settings, we propose that doxycycline might be useful as a treatment to prevent recurrence following trichiasis surgery.

Doxycycline inhibits matrix metalloproteinase-2 secretion from TSC2-null mouse embryonic fibroblasts and lymphangioleiomyomatosis cells

BACKGROUND AND PURPOSE

Lymphangioleiomyomatosis (LAM) is characterized by the abnormal growth of smooth muscle-like cells (LAM cells) and cystic destruction of the lung parenchyma. LAM cell-derived matrix metalloproteinases (MMPs) are thought to play a prominent role in the tissue destruction. The aim of this study was to determine whether doxycycline, a known MMP inhibitor, can inhibit LAM cell proliferation or mitochondrial function and/or modulate MMPs and their tissue inhibitors (TIMPs).

EXPERIMENTAL APPROACH

Wild-type and tuberous sclerosis complex-2 (TSC2)-null mouse embryonic fibroblasts (MEFs) were cultured in DMEM containing 10% fetal bovine serum (FBS). Human LAM cells were derived from the lungs of LAM patients and airway smooth muscle cells from control subjects. Cells were stimulated with FBS with or without doxycycline for up to 9 days. Proliferation was assessed by manual cell counts and MTT assay, MMP production by zymography and ELISA, and TIMP production using elisa.

KEY RESULTS

Doxycycline did not change FBS-induced proliferation in MEFs or human cells. However, doxycycline did reduce metabolic activity of both wild-type and TSC2-null MEFs and LAM cells, but had no effect on control cells. Furthermore, doxycycline reduced MMP-2 from MEFs and decreased active-MMP-2 from LAM cells but had no effect on TIMP-1 and TIMP-2 from human LAM cells.

CONCLUSIONS AND IMPLICATIONS

Doxycycline decreased MMP levels and cell metabolic activity, which raises the possibility of therapeutic efficacy in LAM.

Imaging the impact of chemically inducible proteins on cellular dynamics in vivo

The analysis of dynamic events in the tumor microenvironment during cancer progression is limited by the complexity of current in vivo imaging models. This is coupled with an inability to rapidly modulate and visualize protein activity in real time and to understand the consequence of these perturbations in vivo. We developed an intravital imaging approach that allows the rapid induction and subsequent depletion of target protein levels within human cancer xenografts while assessing the impact on cell behavior and morphology in real time. A conditionally stabilized fluorescent E-cadherin chimera was expressed in metastatic breast cancer cells, and the impact of E-cadherin induction and depletion was visualized using real-time confocal microscopy in a xenograft avian embryo model. We demonstrate the assessment of protein localization, cell morphology and migration in cells undergoing epithelial-mesenchymal and mesenchymal-epithelial transitions in breast tumors. This technique allows for precise control over protein activity in vivo while permitting the temporal analysis of dynamic biophysical parameters.

Efficacy of doxycycline as add-on to interferon beta-1a in treatment of multiple sclerosis

BACKGROUND

Available evidence shows that tetracycline family has cellular and molecular mechanisms to protect neurons and oligodendrocytes by modulating matrix metalloproteinases. We tried to compare the effectiveness of intramuscular and subcutaneous interferon beta-1a (INF-β1a) in combination with oral doxycycline among patient with relapsing remitting multiple sclerosis (RRMS) and secondary progressive multiple sclerosis (SPMS).

METHODS

A double-blind clinical trial study was conducted at Hamedan University of Medical and Health Sciences in Iran. Sixty patients with definite diagnosis of RRMS or SPMS were treated with doxycycline and 44 µg subcutaneous IFN-β1a three times a week or 30 µg intramuscular IFN-β1a once a week for six months. Neurologic examinations were performed monthly until the end of the treatment. Changes in expanded disability status scale (EDSS) scores, brain magnetic resonance images (MRIs), and frequency of receiving corticosteroid pulse were evaluated before and after the treatment.

RESULTS

Women constituted 88.3% of the participants. The mean age of the patients was 32 years. The mean EDSS scores reduced from 4.5 to 3.0. Based on the frequency of receiving corticosteroid pulse, relapse rate decreased from 3.2 to 0.8. MRI showed that the number, volume, and activity of the lesions decreased among 13.3% of the participants, increased among 15%, and remained persistent among 71.7%.

CONCLUSION

Combination of doxycycline and IFN-β1a can decrease relapse rate and improve EDSS scores in patients with RRMS and SPMS. However, it does not affect MRI changes. Furthercontrolled clinical trials on greater number of patients with MS are needed to evaluate the efficacy of combination therapy.

Systemic Expression of Matrix Metalloproteinase-9 in Patients With Cerebral Arteriovenous Malformations

OBJECTIVE

Increased expression angiogenic factors, such as matrix metalloproteinases (MMPs), are associated with the formation of cerebral arteriovenous malformations (AVMs). The objective of this study was to determine plasma levels of MMP-9 of patients with AVMs.

METHODS

Blood samples were drawn from 15 patients with AVMs before treatment, 24 hours postembolization, 24 hours postresection, and 30 days postresection. Blood samples were also obtained from 30 healthy controls. Plasma MMP-9 concentrations were measured via enzyme-linked immunosorbent assay.

RESULTS

The mean plasma MMP-9 level in AVM patients at baseline was significantly higher than in control patients: 108.04 ± 16.11 versus 41.44 ± 2.44 ng/mL, respectively. The mean plasma MMP-9 level 1 day after embolization increased to 172.35 ± 53.76 ng/mL, which was not significantly elevated over pretreatment levels. One day after resection, plasma MMP-9 levels increased significantly over pretreatment levels to 230.97 ± 51.00 ng/mL. Mean plasma MMP-9 concentrations 30 days after resection decreased to 92.8 ± 18.7 ng/mL, which was not different from pretreatment levels but was still significantly elevated over control levels. MMP-9 levels did not correlate with patient sex, age, presentation, or AVM size.

CONCLUSION

Plasma MMP-9 levels are significantly elevated over controls at baseline, increase significantly immediately after surgery, and decrease to pretreatment levels during follow-up.

Soluble endoglin modulates aberrant cerebral vascular remodeling

OBJECTIVE

Brain arteriovenous malformations (AVMs) are an important cause of neurological morbidity in young adults. The pathophysiology of these lesions is poorly understood. A soluble form of endoglin (sEng) has been shown to cause endothelial dysfunction and induce preeclampsia. We tested if sEng would be elevated in brain AVM tissues relative to epilepsy brain tissues, and also investigated whether sEng overexpression via gene transfer in the mouse brain would induce vascular dysplasia and associated changes in downstream signaling pathways.

METHODS

Expression levels of sEng in surgical specimens were determined by Western blot assay and enzyme-linked immunosorbent assay. Vascular dysplasia, levels of matrix metalloproteinase (MMP), and oxidative stress were determined by immunohistochemistry and gelatin zymography.

RESULTS

Brain AVMs (n = 33) had higher mean sEng levels (245 +/- 175 vs 100 +/- 60, % of control, p = 0.04) compared with controls (n = 8), as determined by Western blot. In contrast, membrane-bound Eng was not significantly different (108 +/- 79 vs 100 +/- 63, % of control, p = 0.95). sEng gene transduction in the mouse brain induced abnormal vascular structures. It also increased MMP activity by 490 +/- 30% (MMP-9) and 220 +/- 30% (MMP-2), and oxidants by 260 +/- 20% (4-hydroxy-2-nonenal) at 2 weeks after injection, suggesting that MMPs and oxidative radicals may mediate sEng-induced pathological vascular remodeling.

INTERPRETATION

The results suggest that elevated sEng may play a role in the generation of sporadic brain AVMs. Our findings may provide new targets for therapeutic intervention for patients with brain AVMs. Ann Neurol 2009;66:19-27.

Doxycycline-mediated inhibition of choroidal neovascularization

PURPOSE

Doxycycline, a broad-spectrum antibiotic, has certain antiangiogenic properties and can inhibit matrix metalloproteinases (MMPs/gelatinases). The authors investigated the effects of doxycycline on choroidal neovascularization (CNV) and regulation of MMP-2 and -9 and pigment epithelium-derived factor (PEDF).

METHODS

Doxycycline was orally administered to rats at 500, 50, 5, and 0.5 mg/kg/d; nontreated animals were used as controls. Experimental CNV was induced with laser 7 days after doxycycline treatment started. At 7 days after induction, animals were euthanatized, and eyes were collected. RPE/choroid flatmounts were labeled with isolectin IB4 to determine CNV lesion volumes using confocal microscopy and high-performance 3D imaging software. MMP-2, MMP-9, and PEDF protein levels were determined by ELISA. MMP catalytic activity was determined in solution using fluorogenic gelatin and peptide substrates, by gelatin zymography in SDS-PAGE, and by in situ fluorogenic substrate zymography in RPE/choroid sections.

RESULTS

CNV complex lesion volumes decreased with doxycycline in a dose-response relationship. A dosage of 500 mg/kg/d caused a 70% inhibition of CNV complex volume compared with control animals. Doxycycline elevated PEDF levels in plasma and did not affect the active and pro-enzymes MMP-2 and MMP-9 levels. However, the in vitro enzymatic activities of purified MMP-2 and MMP-9 declined significantly with doxycycline. MMP-2, MMP-9, and gelatinolytic activities in situ increased early in CNV lesion development. Doxycycline treatments and exogenous additions inhibited gelatinolytic activities in CNV lesions.

CONCLUSIONS

Doxycycline effectively hampered the progression of experimental CNV. The results suggest that orally administrated doxycycline can reach the choroid to attenuate proteolytic enzymes that remodel Bruch's membrane and promote the antiangiogenic PEDF to inhibit neovascularization.