Repair, Regeneration, and Fibrosis

Coordinator: Jim Fishback, M.D.

The extracellular matrix

1. The collagens, Table 3-1 (the book lists 10 types, the first 4 are the most relevant)
2. Basement membranes - found in all organs containing epithelia. Liver is an exception. Also found beneath endothelium, except for the fenestrated endothelium of the reticuloendothelial system, and (again), in the liver.
3. Elastic fibers - uterus, blood vessels, skin, and lung.
4. Structural glycoproteins
   • Fibronectin - ubiquitous in the extracellular matrix.
5. Proteoglycans - bind to collagen, help to organize the extracellular matrix.

Cell proliferation

The cell cycle (Figure 3-5, page 77)

• Labile cells (e.g., intestinal epithelium, skin) These cells are continually shed, and, therefore, must continually regenerate.
• Stable cells (have potential regenerative capacity, when needed)
  • Acute tubular necrosis, oliguric phase
  • Acute tubular necrosis, regenerative phase
• Permanent cells (e.g., CNS neurons) These cells do not divide.

Cell-Matrix Interactions

Cell migration

• Margination and diapedesis

Cell-Cell Interactions

• MDGF
• PDGF
• EGF
• FGF
• TGF

Wound healing

• Duodenum, multiple peptic ulcers, gross
• Duodeneum, peptic ulcer, photomicrograph, overview
• Granulation tissue (see also Figure 3-10, pg. 84)
• Healing of wounds with apposed edges (Primary Intention, Figure 3-13, pg. 89)
• Healing of wounds with separated edges (Secondary Intention)
• Factors that influence wound healing
• Complications of wound healing
  • Excessive scar formation
    • keloid (see also Figure 3-14, pg. 91)
  • infection

Healing in specific tissues

• Bone (Figure 26-15, page 1290-1291)
• Liver (see also Figure 3-16, pg. 94)
  • Alcoholic liver disease
    • Portal hypertension, with ascites
    • Alcoholic cirrhosis, cut surface
    • Alcoholic cirrhosis, photomicrograph, trichrome stain
  • Congestive heart failure
    • Chronic passive congestion, liver, gross (Nutmeg liver)
    • Chronic passive congestion, liver, micro
    • Central fibrosis, liver (cardiac cirrhosis), gross
  • Chronic active hepatitis
    • Chronic active hepatitis, (macronodular cirrhosis), gross
    • Chronic active hepatitis, (macronodular cirrhosis), scanning power
    • Chronic active hepatitis, (macronodular cirrhosis), micro, medium power
    • Chronic active hepatitis, (macronodular cirrhosis), micro, high power
• Kidney
  • acute pyelonephritis, gross
  • acute pyelonephritis, micro
  • chronic pyelonephritis, gross
  • chronic pyelonephritis, pelvis, micro
  • chronic pyelonephritis, medulla, micro
• Heart (Fig. 3-17, pg. 94)
  • Myocardial infarcts, recent and remote
  • Acute myocardial infarct, with left ventricular rupture, hemopericardium, and cardiac tamponade
  • Acute myocardial infarct, with left ventricular rupture, gross, heart
• Nervous system (Fig. 28-11, pg. 1377)
  • Glial scar