Fibroblast

Fibroblast

1. is one of the most abundant cell types present in the stroma.

2. composes the basic framework

   • for tissues
   • for organs.

3. has a variety of functions

   • Under homeostasis
     • this cell is responsible for maintaining the extracellular matrix (ECM)
   • During stress
     • adapt to their environment
     • have the ability to respond and send local signals
   • In times of injury
     • can transform phenotypes
     • synthesize the building blocks necessary to replace wounded tissue

4. from a mesenchymal origin

   • it have an elongated spindle
     • or stellate shape with a multitude of cytoplasmic projections

5. Structure

   • Within the cytoplasm is
     • a large Golgi apparatus.
     • an abundance of rough endoplasmic reticulum (rER)

6. are the most common cell type represented in connective tissue

7. These cells produce a diverse group of products including

   • collagen type
     • I
     • III
     • IV
   • proteoglycans
   • fibronectin
   • laminins
   • glycosaminoglycans
   • metalloproteinases,
   • prostaglandins

8. In the adult body

   • fibroblasts remain in a quiescent form until
     • stimuli activate protein synthesis
     • contractile mechanisms

9. These cells synthesize reorganize the ECM found in

   • the skin
   • lung
   • heart
   • Kidney
   • Liver
   • eye

10. can secrete and respond to

    • autocrine signals
    • paracrine signals

11. are known for

    • their plasticity
    • endothelial cells
    • adipocytes
    • epithelial cells
    • pericytes

12. The ability of fibroblasts to transform

    • partly due to the variety of cell-surface adhesion receptors
      • integrins
      • syndecans
      • cadherins
      • that facilitate the communication of fibroblasts with their surroundings

13. are present in both healthy and pathologic tissues

14. contain features of fibroblasts and smooth muscle cells

15. Proper specimens must be obtained to analyze fibroblasts microscopically.

    • The specific type of tissue is obtained by methods dependent
      • on the organ
      • depth required for an accurate tissue sample
        • Example
          • Excisional surgical specimens
          • punch biopsies
          • shave biopsies
      • Tissue Preparation
        • preserving the tissue in formalin
        • sectioned
        • embedded in paraffin
        • stained
          • Immunohistochemical staining has had poor success in distinguishing fibroblasts
            • as there are no fibroblast specific markers.
          • The result is the staining of multiple cells that overlap in specificity
            • Immunofluorescence (IF) techniques can be deployed to compare
              • fibroblasts
              • myofibroblasts

16. microscopy

    • Microscopy light
      • fibroblasts are elongated, disc-like structures that are not readily visible upon standard light microscopy evaluation.
    • Microscopy Electron
      • Transmission electron microscopy reveals abundant rER and Golgi apparatuses in the cell cytoplasm.

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