Patient assessment
Michael Parker, Charlie James in Fundamentals for Cosmetic Practice, 2022
Despite being blocked, sebaceous glands continue to produce sebum, despite it having no clear route of drainage. This may be an occult process, with the pilosebaceous unit slowly increasing in size within the dermis, unbeknownst to the patient. This process is further compounded by the effects of bacteria, such as Propionibacterium acnes, which feed off the oily sebum and as a by-product of this produces the pro-inflammatory protein complex NF-ΚB and the production of leukotrienes through the activation of the enzyme 5-lipoxygenase. The inflamma-tory response to P. acnes results in the formation of pustules as immune cells are drawn to the infected pilosebaceous units to try and destroy the bacterial infection. These pustules appear as small white pockets of fluid which commonly have a surrounding erythematous reaction, forming the characteristic lesions seen in acne. Should the pressure within an infected pilosebaceous gland become too great, then these lesions may spontaneously erupt with the infection draining spontaneously. Sadly, for the patient, the localised pockets of inflammation caused by P. acnes can be quite severe when infections track deeper into the dermis. These deeper infections are not only more difficult to treat but are also likely to result in permanent scarring.
Nanomedicines for Ocular NSAIDs: State-of-the-Art Update of the Safety on Drug Delivery
Lajos P. Balogh in Nano-Enabled Medical Applications, 2020
The main products of the cyclo-oxygenase (COX) pathway are prostaglandins (PGs), probably derived from the iris ciliary body [28]. PGs cause miosis, increase in vascular permeability of the blood–ocular barriers and changes in intraocular pressure. Furthermore, they possess chemokinetic activity and can serve as mediators in both humoral and cellular phases of the inflammatory response [24, 25]. The main products of lipoxygenase (LO) pathway are leukotrienes (LT) such as LT B4 and peptidoleukotrienes. LT B4 causes aggregation of polymorphonuclear cells, exudation of plasma, translocation of calcium and stimulation of phospholipase A2 [24, 29]. Peptidoleukotrienes result in bronchoconstriction, secretion of mucus, plasma leakage from post capillary venules, vasoconstriction of arterioles and miosis.
Epithelial Cells
Bruce S. Bochner in Adhesion Molecules in Allergic Disease, 2020
Mammalian respiratory epithelia are characterized by the 5-, 12-, and 15-lipoxygenase pathways (198), the last of which predominates in the human host (201). The 15-lipoxygenase enzyme converts arachidonic acid to the metabolically important 15-hydroxyeicosatetraenoic acid (15-HETE) and a broad range of hydroperoxy-, epoxyhydroxy-, keto-, and dihydroxy-acids (199,201). Murray et al. (202) were the first to report significant levels of 15-HETE in the BAL fluids of chronic stable asthmatics subjected to antigen provocation. It was not clear, however, that airway epithelial cells were the source of this metabolite because eosinophils also contain high levels of 15-lipoxygenase (203). Activity of 15-lipoxygenase has since been shown to be increased in asthmatic bronchial epithelium by both metabolic assay (204) and direct immunohistochemical staining (205).
Inflammation resolution and specialized pro-resolving lipid mediators in chronic rhinosinusitis
Published in Expert Review of Clinical Immunology, 2023
Peyton Z. Robinson, Daniel N. Frank, Vijay R. Ramakrishnan
Mechanisms by which arachidonic acid-derived lipoxins promote resolution of inflammation include: reduction of neutrophil chemotaxis in response to leukotriene B4 and prostaglandins, increasing monocyte infiltration and vascular permeability, inhibiting production of reactive oxygen species, and stimulating clearance of apoptotic neutrophils by macrophages (Table 1) [50,54]. Lipoxin A4 (LXA4) and Lipoxin B4 (LXB4) are synthesized through two established pathways: 1) by 15-Lipoxygenase (15-LOX) and 5-Lipoxygenase (5-LOX), with 15-hydroxyeicosatetraenoic acid (15-HETE) as the intermediate or 2) using 5-LOX and 12-Lipoxygenase (12-LOX) with 5-hydroxyeicosatetraenoic acid (5-HETE) as the intermediate [52]. 15-HETE is also a stable intermediate that can be reliably assayed, and has pro-resolving capabilities similar to lipoxins [53].
Evening primrose oil attenuates oxidative stress, inflammation, fibrosis, apoptosis, and ultrastructural alterations induced by metanil yellow in the liver of rat: a histological, immunohistochemical, and biochemical study
Published in Ultrastructural Pathology, 2023
Amany Mohamed Shalaby, Rania H. Shalaby, Mohamed Ali Alabiad, Doaa I. Abdelrahman, Mohammed Alorini, Fatima A. Jaber, Shaimaa Mohamed Abdelfattah Hassan
Herbs were formerly utilized as traditional remedies to manage various ailments, but they are today utilized in pharmacies, fragrances, nutritional supplements, and drinks.7 Evening primrose oil (EPO) is a popular traditional medicine that contains a variety of phytocompounds, such as flavonoids, tannins, esters, triterpenoids, phenolic acids, fatty acids, lactones, sterols, and chalcones.8 The radical-scavenging and anti-oxidant properties of EPOhave been proven in several investigations.9 It was also reported to have a potent lipoxygenase inhibitory action, supporting its anti-inflammatory properties.10 Previous studies emphasized its hypocholesterolemic, hypoglycemic, anti-bacterial, and anti-fungal effects.11 Vast clinical studies were conducted to evaluate the efficacy of EPO in the treatment of many disorders, including diabetic neuropathy, multiple sclerosis, rheumatoid arthritis, atopic eczema, heart disease, nephropathy, gastrointestinal problems, psychosis, alcohol dependence, and memory loss.12
Anti-Angiogenic Effect of Cantharellus cibarius Extracts, its Correlation with Lipoxygenase Inhibition, and Role of the Bioactives Therein
Published in Nutrition and Cancer, 2022
Sandesh J. Marathe, Wahiba Hamzi, Abdulla M. Bashein, Jan Deska, Tuulikki Seppänen-Laakso, Rekha S. Singhal, Salem Shamekh
Progression of cancer is a complex phenomenon which also involves various enzymes. Lipoxygenase (LOX) is one such enzyme which plays a role in cancer progression. LOX plays a role in synthesis of leukotrienes (LT) which are inflammatory mediators (13). LOX also plays a crucial role in enhancing the expression of vascular endothelial growth factor (VEGF) (14), thus ultimately affecting angiogenesis and cancer progression. Furthermore, a rise in the expression of LOX has been correlated with upregulation of matrix metalloprotease (MMP)-2 and VEGF, which are the key factors involved in angiogenesis (15). Inhibiting LOX has been shown to lower the activity of MMP and VEGF (15, 16). LOX has been reported to affect oral carcinogenesis and has been targeted for cancer prevention (17). Thus, the inhibition of LOX has gained the interest of researchers as a means of studying not only the anti-inflammatory effect, but also the anti-angiogenic potential.
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