URINARY TRACT INFLAMMATION

R.A.S HEMAT, MB;BCh, FRCSI, DUL.

The inflammatory processes are modulated by a number of different cellular and plasma including serine proteases, metalloproteinase, cationic proteins, acid hydrolyases, myeloperoxidase, and lactoferrin. Proteinases, in addition to their role in cellular cytotoxicity, can influence monocytes motility and chemotaxis, modulate cytokines responses, contribute to mononuclear cell proliferation, or induce target cell apoptosis.

Inflammation is mediated by a variety of soluble factors, including a group of secreted polypeptides known as cytokines. Invading microbes are constantly subject to host immune surveillance. During early stages of invasion, white cells and plasma proteins take part in an inflammatory response, non-specific counter-attack, phagocytic white cells ingest invaders. The inflammatory response begins with changes in blood flow to the besieged tissue.
Superoxide is a moderately reactive compound capable of acting as an oxidant or reductant in biologic systems, diffuse for considerable distances before it exerts its toxic effects. Many biochemical reactions vital to normal aerobic metabolism of human and microbial cells require the transfer of 4 electrons to molecular oxygen to form H2O. Chemotaxis is achieved by regulating the direction of bacterial flagellar rotation. E. coli swim by rotating their flagella. Each flagellum is driven by a motor. Bacterial pathogens must adapt to a wide variety of changing environment conditions during the infection cycle. Many pathogenic microorganisms specifically target host-cell receptors that normally mediate intercellular interactions, attachment to substrata..etc.

Epithelial cells that line mucosal surfaces are important mechanical barriers that separate the host’s internal milieu from the external environment. The recruitment of circulating neutrophils/monocytes from blood into sites of tissue injury is a crucial component of the inflammatory response, which involves a highly regulated series of cellular responses and the local production of inflammatory mediators

Binding of appropriate stimuli to cell surface receptors of phagocyte leads to increased consumption of oxygen concomitant with the formation and secretion of superoxide anion by a plasma membrane associated NADPH-oxidase. C5a is capable of amplifying the inflammatory responses via its chemoattractant properties, its induction of granule release in phagocytic cells, and its ability to induce phagocyte generation of oxygen metabolites.
Cytokines play a key role in the pathogenesis of inflammatory tissue injury associated with the rejection of transplanted organs, pulmonary fibrosis, septic shock, and inflammatory skin conditions, Ischaemia-reperfusion injury, glomerulonephritis, endotoxin, immune-complex-induced diseases. The acute phase response is an orchestrated response to tissue injury, infection or inflammation.

Inflammation is a complex tissue response to injury in which a network of chemical signals initiates and maintains the host response by stimulating endothelial cells, inducing leukocytes recruitment and activating phagocytic leukocyte functions. The recruitment of circulating leukocytes into tissue is initiated by adherence of circulating leukocytes to activated vascular endothelial cells in inflamed tissues, and subsequent transmigration through the endothelial cells. In adults most inflammation responses resolve with development of scar tissue.
Sympathetic efferents are involved in the pain of inflammation. The release of peptides from primary afferents and norepinephrine (NE) and prostaglandins from sympathetic efferents are significant contributors to the pain, swelling and plasma extravasation that occurs in inflammation. Inflammation leads to a considerable increase in the proportions of sympathetic axons that express ionotropic glutamate receptors.
Tropism is the phenomenon by which commensal and pathologic bacteria are restricted to certain host's tissues and cell types. Tropism helps to explain the diversity of bacteria known to cause certain diseases. The architecture of the outer surface of bacteria modulates the interaction with environment, including the ability of the bacteria to interact with only certain cells and tissues.

Ascending infection is assumed to be the means by which cystitis and pyelonephritis occur. E. coli is normally present in the gut first colonises the perineum in female patients or the prepuce of uncircumcised male patients before causing an ascending infection. Nonobstructive acute pyelonephritis is caused most often by P-fimbriated E. coli, as reported in more than 95% of children and 50-90% of adults. P-fimbriae are heteropolymeric structures composed of a rigid stalk containing the major protein linked end to..etc.

Some activated complement proteins promote inflammation. The invader ends up with a complement coat, which adheres to the phagocytes. Once established, a chronic inflammatory process appears to take on a momentum of its own...etc.

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Dr. R.A.S HEMAT declares no conflicts of interest or financial interests in any product or service mentioned in this article, including grants, employment, stock holdings, gifts, or honoraria.