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Mast cells in inflammatory arthritis.

Nigrovic PA, Lee DM - Arthritis Res. Ther. (2004)

Bottom Line: This finding highlights the results of more than 20 years of research indicating that mast cells are frequent participants in non-allergic immune responses as well as in allergy.Accumulating within inflamed tissues, mast cells produce cytokines and other mediators that may contribute vitally to ongoing inflammation.Here we review some of the non-allergic functions of mast cells and focus on the potential role of these cells in murine and human inflammatory arthritis.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, Massachusetts, USA.

ABSTRACT
Mast cells are present in limited numbers in normal human synovium, but in rheumatoid arthritis and other inflammatory joint diseases this population can expand to constitute 5% or more of all synovial cells. Recent investigations in a murine model have demonstrated that mast cells can have a critical role in the generation of inflammation within the joint. This finding highlights the results of more than 20 years of research indicating that mast cells are frequent participants in non-allergic immune responses as well as in allergy. Equipped with a diversity of surface receptors and effector capabilities, mast cells are sentinels of the immune system, detecting and delivering a first response to invading bacteria and other insults. Accumulating within inflamed tissues, mast cells produce cytokines and other mediators that may contribute vitally to ongoing inflammation. Here we review some of the non-allergic functions of mast cells and focus on the potential role of these cells in murine and human inflammatory arthritis.

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Related in: MedlinePlus

Mast cells within the rheumatoid synovium. Shown is fixed, paraffin-embedded synovial tissue obtained during arthroplasty from a patient with chronic rheumatoid arthritis. This tissue was stained with safranin-O, which labels mast cell granule proteoglycans red, and counterstained with hematoxylin. Note the frequent safranin-O-positive mast cells present within the synovial sublining (several indicated with arrows). A fold of thickened synovial lining is seen at the bottom left of the image (outlined with a dotted line) and a blood vessel (BV) is visible in the middle of the field, with erythrocytes staining blue. (Section 5 μm thick; original magnification ×400.)
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Figure 1: Mast cells within the rheumatoid synovium. Shown is fixed, paraffin-embedded synovial tissue obtained during arthroplasty from a patient with chronic rheumatoid arthritis. This tissue was stained with safranin-O, which labels mast cell granule proteoglycans red, and counterstained with hematoxylin. Note the frequent safranin-O-positive mast cells present within the synovial sublining (several indicated with arrows). A fold of thickened synovial lining is seen at the bottom left of the image (outlined with a dotted line) and a blood vessel (BV) is visible in the middle of the field, with erythrocytes staining blue. (Section 5 μm thick; original magnification ×400.)

Mentions: The synovium of patients with RA is an archetypal example of a chronically inflamed tissue characterized by an expanded population of mast cells (Fig. 1). In the normal joint, the synovium consists of a thin lining layer of macrophages (macrophage-like synoviocytes, 'Type A' cells) and fibroblasts (fibroblast-like synoviocytes, 'Type B' cells) embedded in a connective tissue matrix and resting on a sublining of highly vascular loose connective tissue and adipose tissue. In the absence of inflammation, scattered mast cells are seen in the sublining, clustered around vessels and nerves and forming up to 3% of all cells within the synovium [47]. The role of mast cells in the normal synovium remains to be defined, although the importance of mouse peritoneal mast cells for defense against bacterial peritonitis suggests that one important function of synovial mast cells might be to monitor the vulnerable acellular joint cavity for early evidence of infection.


Mast cells in inflammatory arthritis.

Nigrovic PA, Lee DM - Arthritis Res. Ther. (2004)

Mast cells within the rheumatoid synovium. Shown is fixed, paraffin-embedded synovial tissue obtained during arthroplasty from a patient with chronic rheumatoid arthritis. This tissue was stained with safranin-O, which labels mast cell granule proteoglycans red, and counterstained with hematoxylin. Note the frequent safranin-O-positive mast cells present within the synovial sublining (several indicated with arrows). A fold of thickened synovial lining is seen at the bottom left of the image (outlined with a dotted line) and a blood vessel (BV) is visible in the middle of the field, with erythrocytes staining blue. (Section 5 μm thick; original magnification ×400.)
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC1064877&req=5

Figure 1: Mast cells within the rheumatoid synovium. Shown is fixed, paraffin-embedded synovial tissue obtained during arthroplasty from a patient with chronic rheumatoid arthritis. This tissue was stained with safranin-O, which labels mast cell granule proteoglycans red, and counterstained with hematoxylin. Note the frequent safranin-O-positive mast cells present within the synovial sublining (several indicated with arrows). A fold of thickened synovial lining is seen at the bottom left of the image (outlined with a dotted line) and a blood vessel (BV) is visible in the middle of the field, with erythrocytes staining blue. (Section 5 μm thick; original magnification ×400.)
Mentions: The synovium of patients with RA is an archetypal example of a chronically inflamed tissue characterized by an expanded population of mast cells (Fig. 1). In the normal joint, the synovium consists of a thin lining layer of macrophages (macrophage-like synoviocytes, 'Type A' cells) and fibroblasts (fibroblast-like synoviocytes, 'Type B' cells) embedded in a connective tissue matrix and resting on a sublining of highly vascular loose connective tissue and adipose tissue. In the absence of inflammation, scattered mast cells are seen in the sublining, clustered around vessels and nerves and forming up to 3% of all cells within the synovium [47]. The role of mast cells in the normal synovium remains to be defined, although the importance of mouse peritoneal mast cells for defense against bacterial peritonitis suggests that one important function of synovial mast cells might be to monitor the vulnerable acellular joint cavity for early evidence of infection.

Bottom Line: This finding highlights the results of more than 20 years of research indicating that mast cells are frequent participants in non-allergic immune responses as well as in allergy.Accumulating within inflamed tissues, mast cells produce cytokines and other mediators that may contribute vitally to ongoing inflammation.Here we review some of the non-allergic functions of mast cells and focus on the potential role of these cells in murine and human inflammatory arthritis.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, Massachusetts, USA.

ABSTRACT
Mast cells are present in limited numbers in normal human synovium, but in rheumatoid arthritis and other inflammatory joint diseases this population can expand to constitute 5% or more of all synovial cells. Recent investigations in a murine model have demonstrated that mast cells can have a critical role in the generation of inflammation within the joint. This finding highlights the results of more than 20 years of research indicating that mast cells are frequent participants in non-allergic immune responses as well as in allergy. Equipped with a diversity of surface receptors and effector capabilities, mast cells are sentinels of the immune system, detecting and delivering a first response to invading bacteria and other insults. Accumulating within inflamed tissues, mast cells produce cytokines and other mediators that may contribute vitally to ongoing inflammation. Here we review some of the non-allergic functions of mast cells and focus on the potential role of these cells in murine and human inflammatory arthritis.

Show MeSH
Related in: MedlinePlus