A Simplified Framework for Describing the Phases of Inflammation

The inflammatory response is a complex and highly regulated process. A simplified framework for discussing inflammatory response is outlined below. Each of the three phases involve a series of coordinated events and interactions between various immune cells, signaling molecules, and tissue components.

1. Initiation:
   • Recognition of Pathogens or Damage:
     • Immune cells detect PAMPs or DAMPs through PRRs (e.g., TLRs, NLRs).
     • Activation of PRRs triggers the release of inflammatory mediators.
2. Effector Mechanisms:
   • Vasodilation and Increased Permeability:
     • Cytokines, chemokines, lipid mediators, and histamine release leads to vasodilation and increased permeability of blood vessels.
   • Recruitment of Immune Cells:
     • Chemokines attract neutrophils and monocytes to the site of inflammation.
   • Phagocytosis and Inflammatory Mediator Production:
     • Neutrophils, monocytes, DCs, and macrophages phagocytose pathogens, releasing cytokines and chemokines.
3. Resolution:
   • Anti-inflammatory Signals and Termination of Inflammation:
     • Production of anti-inflammatory cytokines (e.g., IL-10) counters pro-inflammatory signals.
     • Negative feedback loops inhibit inflammatory pathways.
   • Tissue Repair and Return to Homeostasis:
     • Activation of fibroblasts contributes to tissue repair.
     • Clearance of apoptotic immune cells and debris by macrophages.
     • Restoration of tissue function and return to homeostasis.

Next Topic: Details Related to the Effector Phase of Inflammation

Source: ChatGPT response prompted and edited by Joel Graff.

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