Marimastat inhibits neointimal thickening in a model of human arterial intimal hyperplasia

Neutralizing Effects of Small Molecule Inhibitors and Metal Chelators on Coagulopathic Viperinae Snake Venom Toxins

Animal-derived antivenoms are the only specific therapies currently available for the treatment of snake envenoming, but these products have a number of limitations associated with their efficacy, safety and affordability for use in tropical snakebite victims. Small molecule drugs and drug candidates are regarded as promising alternatives for filling the critical therapeutic gap between snake envenoming and effective treatment. In this study, by using an advanced analytical technique that combines chromatography, mass spectrometry and bioassaying, we investigated the effect of several small molecule inhibitors that target phospholipase A2 (varespladib) and snake venom metalloproteinase (marimastat, dimercaprol and DMPS) toxin families on inhibiting the activities of coagulopathic toxins found in Viperinae snake venoms. The venoms of Echis carinatus, Echis ocellatus, Daboia russelii and Bitis arietans, which are known for their potent haemotoxicities, were fractionated in high resolution onto 384-well plates using liquid chromatography followed by coagulopathic bioassaying of the obtained fractions. Bioassay activities were correlated to parallel recorded mass spectrometric and proteomics data to assign the venom toxins responsible for coagulopathic activity and assess which of these toxins could be neutralized by the inhibitors under investigation. Our results showed that the phospholipase A2-inhibitor varespladib neutralized the vast majority of anticoagulation activities found across all of the tested snake venoms. Of the snake venom metalloproteinase inhibitors, marimastat demonstrated impressive neutralization of the procoagulation activities detected in all of the tested venoms, whereas dimercaprol and DMPS could only partially neutralize these activities at the doses tested. Our results provide additional support for the concept that combinations of small molecules, particularly the combination of varespladib with marimastat, serve as a drug-repurposing opportunity to develop new broad-spectrum inhibitor-based therapies for snakebite envenoming.

P2X7 receptor antagonism modulates IL-1β and MMP9 in human atherosclerotic vessels

In atherosclerosis, matrix metallopeptidases (MMPs) contribute to plaque rupture through weakening of the fibrous cap. Pleiotropic P2X purinoceptor 7 (P2X7), expressed in the carotid plaque (PL), is involved in interleukin 1 beta (IL-1β) release that may influence MMP9 generation, thus their possible modulation through acting on P2X7 was investigated. P2X7-related machinery was characterized and the effects of P2X7 antagonists (A740003, KN62) and MMPs inhibitors (Batimastat, Ro28-2653) were studied in ex-vivo tissue cultures of human PL’s vs. non-atherosclerotic internal mammary artery (IMA) by using molecular biology, immune-biochemical and microscopy methodologies. We highlighted atherosclerosis-related differences between PLs and IMAs molecular patterns, and their responsivity to P2X7 antagonism. High IL-1β tissue content was associated with PLs morphology and instability/vulnerability. We demonstrated that A740003, but not KN62, decreased IL-1β and MMP9 independently from NLR family pyrin domain containing 3, but in relationship with patient’s smoking status. Acting downstream P2X7 by MMPs inhibitors, diminished IL-1β mRNA without transcriptional effect at MMP9, possibly because the assumption of statin by patients. These data firstly demonstrated A740003 suitability as a specific tool to decrease inflammatory status in human vessels and might support the design of studies applying P2X7 antagonists for the local targeting and tailored therapy of atherosclerosis.

Identify potential drugs for cardiovascular diseases caused by stress-induced genes in vascular smooth muscle cells

BACKGROUND

Abnormal proliferation of vascular smooth muscle cells (VSMC) is a major cause of cardiovascular diseases (CVDs). Many studies suggest that vascular injury triggers VSMC dedifferentiation, which results in VSMC changes from a contractile to a synthetic phenotype; however, the underlying molecular mechanisms are still unclear.

METHODS

In this study, we examined how VSMC responds under mechanical stress by using time-course microarray data. A three-phase study was proposed to investigate the stress-induced differentially expressed genes (DEGs) in VSMC. First, DEGs were identified by using the moderated t-statistics test. Second, more DEGs were inferred by using the Gaussian Graphical Model (GGM). Finally, the topological parameters-based method and cluster analysis approach were employed to predict the last batch of DEGs. To identify the potential drugs for vascular diseases involve VSMC proliferation, the drug-gene interaction database, Connectivity Map (cMap) was employed. Success of the predictions were determined using in-vitro data, i.e. MTT and clonogenic assay.

RESULTS

Based on the differential expression calculation, at least 23 DEGs were found, and the findings were qualified by previous studies on VSMC. The results of gene set enrichment analysis indicated that the most often found enriched biological processes are cell-cycle-related processes. Furthermore, more stress-induced genes, well supported by literature, were found by applying graph theory to the gene association network (GAN). Finally, we showed that by processing the cMap input queries with a cluster algorithm, we achieved a substantial increase in the number of potential drugs with experimental IC50 measurements. With this novel approach, we have not only successfully identified the DEGs, but also improved the DEGs prediction by performing the topological and cluster analysis. Moreover, the findings are remarkably validated and in line with the literature. Furthermore, the cMap and DrugBank resources were used to identify potential drugs and targeted genes for vascular diseases involve VSMC proliferation. Our findings are supported by in-vitro experimental IC50, binding activity data and clinical trials.

CONCLUSION

This study provides a systematic strategy to discover potential drugs and target genes, by which we hope to shed light on the treatments of VSMC proliferation associated diseases.

Doxycycline prevents intimal hyperplasia in vitro and may improve patency of the internal thoracic artery

Objectives. The development of intimal hyperplasia and graft failure is an important problem in cardiac surgery. A fundamental process in intimal hyperplasia is the degradation of extracellular matrix by metalloproteases which induces the vascular smooth-muscle cells migration and sets the scene for graft atherosclerosis. This study investigated whether doxycycline, a metalloproteases inhibitor, can prevent the intimal hyperplasia occurrence in cultured human internal mammary artery, thus extending graft patency. Methods. Segments of internal mammary artery from 20 consecutive patients were prepared and cultured for 2 weeks in serum-supplemented medium (control) or in medium supplemented with 10⁻⁵ M and 10⁻⁶ M doxycycline concentrations. Tissues were fixed, sectioned, and stained, and neointimal thickness was measured by computer-aided image analysis. Further sections were cultured and prepared for gel enzymography to measure the matrix metalloproteinase-2 and -9 levels. Results. At the end of the culture period, neointimal thickness was significantly (P = 0.001) dose-dependently reduced in samples treated with doxycycline when compared with controls. Gelatin enzymography demonstrated a reduction in values for both latent and active forms of metalloproteases. Conclusions. Doxycycline, in a model of internal mammary artery intimal hyperplasia, has a specific role in inhibiting metalloproteases activity and may prevent graft stenosis.

Metalloproteinases in Development and Progression of Vascular Disease

Remodeling of the vascular wall plays a role in many physiological processes, but also in the pathogenesis of major cardiovascular diseases such as restenosis and atherosclerosis. Remodeling requires proteolytic activity to degrade components of the extracellular matrix; this can be generated by the matrix metalloproteinase(MMP) system alone or in concert with the fibrinolytic (plasminogen/plasmin) system. Several lines of evidence suggest that the MMP system plays a role in vascular smooth muscle cell migration and neointima formation after vascular injury. In atherosclerotic lesions, active MMPs may contribute to plaque destabilisation by degrading extracellular matrix components, but may also promote aneurysm formation by proteolytic degradation of the elastic lamina. The MMP system may therefore represent a potential therapeutic target for treatment of restenosis or atherosclerosis.

Metalloproteinase inhibition by batimastat does not reduce neointimal thickening in stented atherosclerotic porcine femoral arteries

BACKGROUND

Vascular injury results in specific temporal patterns of increased matrix metalloproteinase (MMP) activity. MMPs are known to play a role in remodeling and neointimal (NI) thickening. Although in vitro data on the role of metalloproteinases and their inhibitors on smooth muscle cell migration and proliferation are compelling, evidence for inhibition of NI thickening in vivo is inconsistent and is mostly generated in models of balloon angioplasty instead of the more prevalent stent placement. Data from atherosclerotic models are scarce. The objective of the study was to investigate whether the nonspecific MMP inhibitor batimastat, in concentrations known to influence remodeling, could also inhibit NI thickening following stent placement in an atherosclerotic model.

METHODS

Stents were placed in atherosclerotic femoral arteries in Yucatan micropigs on a high cholesterol diet and followed for 6 weeks. Batimastat or vehicle was administered intraperitoneally. NI thickening was assessed by morphometry.

RESULTS

The main finding was that batimastat did not result in a significant decrease in NI thickness. Only following correlation to the amount of preexisting plaque was the difference of 146 microm (19%) statistically significant. Batimastat did not impair wound healing following stenting.

CONCLUSION

Batimastat does not significantly influence the degree of NI thickening at 6 weeks following stenting of atherosclerotic porcine femoral arteries, except when correlated to plaque thickness. Batimastat does not affect vascular wound healing.

Elastinolytic matrix metalloproteinases and their inhibitors as therapeutic targets in atherosclerotic plaque instability

Atherosclerosis is a dynamic pathologic process involving interactions between many cell types and chemical mediators. There is increased evidence in the literature that matrix metalloproteinases, especially those with elastolytic activity, are associated with atherosclerotic plaque instability. Results of recent studies also suggest that the balance between matrix metalloproteinases and their inhibitors contributes to the extracellular matrix integrity, and an imbalance could be a predeterminate of both cerebral and cardiac ischemic events. Significant evidence demonstrates that the balance between elastolytic matrix metalloproteinases and their inhibitors are involved in the atherosclerotic process. Studies investigating pharmacologic therapies that inhibit matrix metalloproteinases or increase their natural inhibitor levels suggest an antiatherosclerotic and potential plaque-stabilizing benefit. Carefully designed clinical trials must be completed to better understand the functions and interactions of these enzymes with the goal of developing selective therapies to prevent the progression and complications of atherosclerosis.

Matrix metalloproteinase inhibitor, marimastat, decreases peritoneal spread of gastric carcinoma in nude mice

Marimastat, a matrix metalloproteinese inhibitor, was examined for the ability to prevent peritoneal dissemination of a human gastric cancer xenograft, TMK-1. Even with novel approaches such as molecular targeting of cancer chemotherapy, peritoneal dissemination of gastric cancer has little sensitivity to anticancer drugs, and it is impossible to inhibit its growth completely. Intraperitoneal injection of TMK-1 into nude mice at 5 x 10( 5) cells / body resulted in carcinomatous peritonitis that mimicked clinical cases. Continuous administration of marimastat (18 mg / kg / day) from 24 h after the tumor inoculation successfully inhibited the growth of peritoneal dissemination nodules. Combined administration of marimastat (18 mg / kg / day) and mitomycin C (MMC, 2 mg / kg) showed synergistic inhibition of growth of peritoneal dissemination, being superior to MMC alone (2 mg / kg). Although marimastat alone could not increase survival time with statistical significance, combined administration of marimastat and MMC had a survival benefit with statistical significance. The combination of marimastat and MMC increased the preventive effect on peritoneal dissemination. Marimastat seems to be a candidate for the prevention of peritoneal spread of gastric carcinoma.