title: Mathematical Model of an Innate Immune Response to Cutaneous Wound in the Presence of Local Hypoxia.
abstract: We developed a 2D multi-agent stochastic model of interaction between cellular debris, bacteria and neutrophils in the surface cutaneous wound with local hypoxia. Bacteria, which grow logistically with a maximum carrying capacity, and debris are phagocytosed by neutrophils with probability determined by the partial pressure of oxygen in the tissue, pO 2  = 4-400 mmHg, according to the Michaelis-Menten equation with K m  = 40 mmHg. The influx of new neutrophils depends linearly (k = 0.05-0.2) on the amount of (a) platelets and (b) neutrophils, which are in contact with bacteria or debris. Each activated neutrophil can accomplish a certain amount of phagocytosis, n max  = 5-20, during its lifespan, T = 1-5 days. The universe of outcomes consists of (a) bacteria clearance (high k and n max ), (b) infection is not cleared by neutrophils (low k and nmax), and (c) intermittent (quasiperiodic) bursts of inflammation. In the absence of infection, phagocytosis stops within 48 h. We found that pO 2 alone did not change the type of outcome, but affects the number of recruited neutrophils and inflammation duration (in the absence of infection by up to 10 and 5 %, respectively).
authors.affiliation: Department of Physics, Ryerson University, Toronto, ON, Canada, M5B 2K3. gsaiko@ryerson.ca.
authors.forename: Guennadi
authors.initials: G
authors.lastname: Saiko
authors.affiliation: Division of Plastic Surg., St. Michael's Hospital, Toronto, ON, Canada, M5B 1W8.
authors.forename: Karen
authors.initials: K
authors.lastname: Cross
authors.affiliation: Department of Physics, Ryerson University, Toronto, ON, Canada, M5B 2K3.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Douplik
mesh_terms: D000818:Animals; D001419:Bacteria / Q000276:immunology; D015687:Cell Hypoxia; D006801:Humans; D007113:Immunity, Innate; D008954:Models, Biological; D018375:Neutrophil Activation; D009504:Neutrophils / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D010100:Oxygen / Q000276:immunology* / Q000378:metabolism; D010313:Partial Pressure; D010587:Phagocytosis; D012867:Skin / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D013269:Stochastic Processes; D013997:Time Factors; D014945:Wound Healing
chemical_list: D010100:Oxygen
keywords: Hypoxia; Inflammation; Neutrophils; Phagocytosis; Wound healing