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Controlled Delivery Models of Bioactive Factors for the Maturation of Engineered Tissues
Published in Emmanuel Opara, Controlled Drug Delivery Systems, 2020
Ashkan Shafiee, Elham Ghadiri, Jareer Kassis, Anthony Atala
Tissue regeneration and organ engineering involve several different steps, starting from performing a cell biopsy on the patient (in the case of autologous tissue engineering), followed by cell culture to obtain a sufficient number of cells,4 tissue fabrication using various biofabrication methods (including but not limited to bioprinting,21,22 and electrospinning23,24), tissue/organ maturation in a designated bioreactor, and ultimately transplantation (Figure 8.1). While some processes that occur during this procedure are naturally innate, it is the responsibility of tissue engineers to investigate and understand the natural external stimuli in orders to both facilitate and accelerate the tissue engineering procedure. For example, it has been shown that, during embryonic development, growth factors drive cells towards a particular behavior by providing essential signals that could also be used for tissue regeneration in an adult.25 Such signaling molecules include mitogens that are responsible for cell division, growth factors that have multiple functions (the most important of which are proliferation), and morphogens that control tissue regeneration.17
Tissue engineering and regenerative medicine
Published in Ronald L. Fournier, Basic Transport Phenomena in Biomedical Engineering, 2017
A variety of cells also secrete soluble proteins known as cytokines. Cytokines serve as intercellular chemical messengers. Many of these proteins are required for the normal development, growth, and proliferation of cells. They are also involved in processes such as inflammation and wound healing and the varied responses of the immune system. Many are mitogens, i.e., they stimulate the proliferation of specific types of cells. They are then referred to as growth factors.
A review on the treatment of intimal hyperplasia with perivascular medical devices: role of mechanical factors and drug release kinetics
Published in Expert Review of Medical Devices, 2023
Ankur J. Raval, Jigisha K. Parikh, Meghal A. Desai
Vascular smooth muscle cells (VSMCs) possess a high degree of plasticity and undergo intense phenotypic alterations when subjected to localized injury [25]. These triggers can switch VSMC’s latent ‘contractile’ phenotype behavior to a proliferative ‘synthetic’ phenotype. These activated VSMCs express a pro-inflammatory phenotype that generates tumor necrosis factors alpha (TNF-α) and monocyte chemoattractant protein-1 (MCP-1/CCL2). Moreover, growth factors like platelet-derived growth factor (PDGF) can mediate inflammation and proliferation via the mitogen-activated protein kinase (MAPK), mammalian target of rapamycin (mTOR), and Hippo signaling pathways that lead to restenosis [26–28]. Such mediators, directly or indirectly, are the targets to control the restenosis cascade. One such example is the drug Sirolimus which directly binds with mammalian target of rapamycin complex 1 (mTORC1), shutting down the cellular sensor of amino acid abundance and growth factor signaling. The mTORC1 manages the core function of nucleotide synthesis, cellular growth, metabolic activities, and, most importantly, proliferation and migration [29]. When Sirolimus binds with mTORC1, the cell cycle arrests the cell replication process at the G1-S phase, thereby preventing VSMC proliferation and migration [30]. Hence, Sirolimus is a preferred drug in drug-eluting stents for coronary artery revascularization [31].
Possible ameliorating effect of isoquercetin on diethylnitrosamine-induced hepatocellular carcinoma in albino mice
Published in Egyptian Journal of Basic and Applied Sciences, 2022
Kholoud A. Omran, Yomna I. Mahmoud, Asmaa A. Mahmoud, Nagui H. Fares
In our result IQ induce apoptosis and inhibit tumor growth, this is in agreement with previous studies of Li et al. (2018) [14] and Shui et al. (2020) [15]. Molecular mechanism of IQ might be closely associated with the mitogen-activated protein kinase and protein kinase C signaling pathways [14,52]. Antioxidants could induce apoptosis in HCC animals [9,55,56], indicating that the anticarcinogenic effect of IQ is possibly linked to apoptosis induction. This finds support in the increased immunohistochemical expression of P53 and PCNA in IQ- treated mice. There was downregulation of immunohistochemical expression of VEGF in IQ -treated mice that support the anti-angiogenesis activity of IQ. The anticarcinogenic effect of IQ could also be attributed to its antiangiogenic effect, manifested by suppressing the overexpressed angiogenic marker VEGF that starves the tumors of their blood supply to avoid the refueling of oxygen and nutrients [9,57], which are crucial to this highly vascular solid tumor with a rapid growth pattern.
Microbiology in Water-Miscible Metalworking Fluids
Published in Tribology Transactions, 2020
Frederick J. Passman, Peter Küenzi
HP has been linked to microbial exposures (158), including fungi (Thermoactinomyces vulgaris, Aspergillus niger, Aspergillus fumigatus, and others) and bacteria (Mycobacterium abscessus, Mycobacterium immunogenum, and others). Occurrence of M. abscessus(159), M. immunogenum(160), and Mycobacterium avium(161) has been reported in MWFs, but M. immunogenum was identified as causative agent at several metalworking facilities where HP clusters occurred. Additionally, it was shown that M. immunogenum activates JNK and p38 mitogen-activated protein kinase in alveolar macrophages. This comes as no surprise due to the fact that mitogen-activated protein kinases are primary agents activated during various stimulations (162). It was reported that M. immunogenum causes HP in mice (163, 164), and M. immunogenum was recovered from MWFs at some facilities where HP clusters had occurred. However, it was not detected at others (165–169). Although it was initially speculated (H. W. Rossmoore, Wayne State University, unpublished) that biocides used to suppress rapidly growing MWF microbes selected for M. immunogenum, Passman et al. (167) subsequently demonstrated that there was no relationship between the abundance of M. immunogenum and that of other MWF microbes. Moreover, Aspergillus spp., Fusarium spp., and yeasts (170) are common MWF fungal contaminants known to cause HP.