Calprotectin: A Critical Biomarker in Inflammation and Disease

Molecular Structure and Composition

Calprotectin is a calcium and zinc-binding protein complex composed of two subunits:

• S100A8 (MRP8 or Calgranulin A)
• S100A9 (MRP14 or Calgranulin B)

These proteins belong to the S100 family of proteins and form heterodimers or heterooligomers in a calcium-dependent manner. The complex has a molecular weight of approximately 24 kDa and demonstrates remarkable stability against temperature and proteolysis.

Biological Functions and Distribution

Cellular Sources

Calprotectin is primarily expressed in:

• Neutrophils (constituting about 60% of cytosolic proteins)
• Monocytes
• Early differentiation stages of macrophages
• Epithelial cells during inflammation

Key Functions

Antimicrobial Activity: Sequesters essential metal ions (zinc and manganese), Creates a nutrient-limited environment for microorganisms, Exhibits direct antimicrobial properties

Inflammatory Response: Acts as a damage-associated molecular pattern (DAMP), Activates toll-like receptor 4 (TLR4), Promotes inflammatory cytokine production, Facilitates leukocyte recruitment

Clinical Applications

Diagnostic Marker

Calprotectin serves as a valuable biomarker in various conditions:

Inflammatory Bowel Disease (IBD): Distinguishes between IBD and IBS, Monitors disease activity, Predicts relapse, Evaluates treatment response

Other Clinical Applications: Rheumatoid arthritis monitoring, Cancer progression assessment, Cardiovascular disease risk evaluation, Detection of neonatal sepsis

Laboratory Testing

Fecal calprotectin measurement:

• Non-invasive diagnostic tool
• High sensitivity and specificity
• Stable at room temperature for several days
• Cost-effective screening method

Pathological Implications

Calprotectin elevation is associated with various pathological conditions:

Gastrointestinal Disorders: Crohn’s Disease, Ulcerative Colitis, Colorectal Cancer, Celiac Disease

Systemic Conditions: Rheumatoid Arthritis, Systemic Lupus Erythematosus, Cardiovascular Diseases, Various Cancer Types

Current Research and Future Perspectives

Active research areas include:

• Development of more sensitive detection methods
• Investigation of novel therapeutic targets
• Understanding its role in cancer biology
• Exploration of its potential in personalized medicine
• Study of its involvement in microbiome regulation

Research continues to uncover new roles and applications for calprotectin in:

• Disease diagnosis
• Treatment monitoring
• Drug development
• Prognostic evaluation

The expanding knowledge of calprotectin’s functions and clinical applications demonstrates its significant potential in both diagnostic and therapeutic approaches to inflammatory diseases and beyond.

Suitable ELISA Kits

• Calprotectin ELISA Kit