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Radiotracer Imaging of Unstable Plaque
Published in Robert J. Gropler, David K. Glover, Albert J. Sinusas, Heinrich Taegtmeyer, Cardiovascular Molecular Imaging, 2007
Macrophages have the capacity when activated by cytokines (TNF-a, IL-1) to secrete inactive metalloproteinases (MMP) (41). The macrophages actively undergoing apoptosis at plaque rupture sites are rich in MMPs. (42) These connective tissue-degrading enzymes include interstitial collagenases (MMP1), gelatinase B (MMP9), stromolysins 1-3 (MMP3, 10, 11), and a membrane type. When activated by plasmin or by inactivation of intrinsic inhibitors in tissue, the MMP can degrade the connective tissue matrix (43). Both MMP mRNA and protein have been found in large amounts in the cap and core area (38). These enzymes are implicated in development of plaque instability by degradation of the fibrous cap. MMP activity may be neutralized by tissue inhibitors of MMP (TIMP) an approach to both therapy and to imaging. A broad based metalloproteinase inhibitor (MPI) was developed and labeled with 123I and in vivo imaging demonstrated focal uptake in the carotids of in ApoE null mice. (44) Another broad based MPI developed by Bristol Meyer Squibb is under investigation in small and large animal models of atherosclerosis.
Polymeric Conjugates for Angiogenesis-Targeted Tumor Imaging and Therapy
Published in Mansoor M. Amiji, Nanotechnology for Cancer Therapy, 2006
Amitava Mitra, Anjan Nan, Bruce R. Line, Hamidreza Ghandehari
MMPs are a family of over 21 zinc-dependent neutral endopeptidases that play an important role in tumor angiogenesis, tissue remodeling, and cell migration.68–70 The two most important MMPs in cancer progression are MMP-2 (gelatinase A) and MMP-9 (gelatinase B).71,72 In cancer, levels of these MMPs are abnormally elevated, enabling cancer cells to degrade the extracellular matrix (ECM), invade the vascular basement membrane, and metastasize to distant sites.70
Immunomodulatory Activities of Silver Nanoparticles (AgNPs) in Human Neutrophils
Published in Huiliang Cao, Silver Nanoparticles for Antibacterial Devices, 2017
Because different biological activities and toxicities of NPs could be related to their initial size (Kim et al. 2015; Mendes et al. 2014; Yin et al. 2015), we performed another study aiming at comparing the effects of AgNP20 to an AgNP with a larger diameter of 70 nm, AgNP70, on the biology of PMNs (Poirier et al. 2015). We demonstrated that unlike AgNP20, AgNP70 did not alter the cell size of PMNs. Also, in contrast to the proapoptotic effect of AgNP20, we found that AgNP70 delay spontaneous neutrophil apoptosis. Interestingly, but intriguingly, AgNP70 were also found to inhibit de novo protein synthesis similarly to AgNP20. Of note, throughout this study, all experiments with AgNP70 and AgNP20 were performed in parallel in the same experimental conditions with PMNs isolated from the same blood donors. In this study, using the general oxidative stress indicator, CM-H2DCFDA, in flow cytometry experiments, we showed that both AgNP20 and AgNP70 did not induce intracellular ROS production. In contrast to AgNP70, AgNP20 were found to increase the production of the potent chemoattractant CXCL8 (IL-8) by PMNs, indicating a different mechanism of action between both AgNPs. Further, in the same order of ideas, we demonstrated that AgNP20, but not AgNP70, induce PMN degranulation, as evidenced by the release of albumin and metalloproteinase-9 (MMP-9/Gelatinase B) in the supernatants (Poirier et al. 2015). This was also confirmed by the detection of gelatinase activity induced by AgNP20 as assessed by zymography experiments. Therefore, collectively, the results of these two studies demonstrate that two AgNPs with different initial diameters, namely, 20 nm or 70 nm, can possess similar as well as different immunomodulatory activities on PMN functions, indicating different modes of action.
Thioredoxin-1 and MMP-9 as biomarkers in breast cancer metastasis in Egyptian female patients
Published in Egyptian Journal of Basic and Applied Sciences, 2018
Al Shaima G. Abd El Salam, Mohamed A. Ebrahim, Laila A. Eissa, Mamdouh M. El-Shishtawy
MMP-9, also known as gelatinase B, is a 92-kDa endopeptidase that is strongly associated with aggressiveness and metastatic spread in breast cancer [14]. During tumor angiogenesis, MMP-9 degrades type IV collagen, the main component of vascular basement membrane surrounding tumor cells which is an essential process in initiation of metastasis. Furthermore, stroma-derived MMP-9 can facilitate the liberation of extracellular matrix (ECM)-sequestered VEGF that leads to metastasis [15].
Age-specific response of skeletal muscle extracellular matrix to acute resistance exercise: A pilot study
Published in European Journal of Sport Science, 2019
Barbara Wessner, Michael Liebensteiner, Werner Nachbauer, Robert Csapo
It is well known that MMPs, particularly gelatinase A (MMP2) and gelatinase B (MMP9) play an important role in the adaptive modifications of skeletal muscle induced by physical exercise (Lo Presti, Hopps, & Caimi, 2017). One of the most interesting findings of our study was the age-specific response of MMP9 to the exercise stimulus: the MMP9 mRNA expression was increased in young but decreased in older subjects. These results are in line with a study in young recreationally active men, where MMP9 mRNA and protein levels were elevated 3 h post knee extension exercises (Patel et al., 2017). To our knowledge no other study so far has reported the exercise-associated MMP9 response in older healthy subjects, but in several models of muscular dystrophy the pharmacological inhibition of MMP9 has been suggested to improve skeletal muscle structure and function and to reduce muscle injury, inflammation and fibre necrosis (Li, Mittal, Makonchuk, Bhatnagar, & Kumar, 2009). However, at later stages of the disease the inhibition of MMP9 may lead to accumulation of fibroadipose tissue and reduced muscle strength (Shiba et al., 2015) showing the multifaceted role of MMP9. Studies performed to investigate the inflammatory processes triggered by resistance exercise may help to interpret the downregulation of MMP9 found in older subjects. One particularly interesting study has suggested that muscles of old adults could be “primed” for a stress response. Such priming is indicated by higher baseline levels of STAT3, NF-κB and HSP70 in muscles of old adults, which may increase the sensitivity to cellular stress and promote inflammatory reactions (Thalacker-Mercer, Dell’Italia, Cui, Cross, & Bamman, 2010). The close connection of the ECM to inflammatory pathways is also evident as the induction of ADAMTS1 gene expression observed in our study could be caused by the infiltration of immune cells to sites of exercise-induced muscle injury. ADAMTS1 functions as an extracellular signal that promotes satellite cell activation and muscle regeneration, at least in young mice (Du et al., 2017).