# Sigumir (KEDG Tetrapeptide) - Khavinson Cartilage & Joint Bioregulator Research 2026
For research purposes only. Not for human use.
Introduction
Sigumir is a synthetic tetrapeptide bioregulator composed of lysine-glutamic acid-aspartic acid-glycine (KEDG), developed by Professor Vladimir Khavinson and the St. Petersburg Institute of Bioregulation and Gerontology (IBRG). As part of the Khavinson bioregulator family, Sigumir is engineered to target cartilage and joint tissue function, supporting research into joint degeneration, osteoarthritis, and cartilage repair mechanisms. The peptide represents a refined approach to tissue-specific regulation, combining the acidic residues of the KED sequence (proven in ovarian tissue) with glycine—a critical component of collagen and cartilage matrix.
Chemical Structure and Molecular Properties
Peptide Sequence
Sigumir is a linear tetrapeptide with the following composition:
L-Lysine (Lys, K) — L-Glutamic Acid (Glu, E) — L-Aspartic Acid (Asp, D) — Glycine (Gly, G)
Molecular Formula: C17H32N6O10
Molecular Weight: 464.47 g/mol
Isoelectric Point (pI): ~3.9 (more acidic than KED)
Net Charge at pH 7.4: −3 (highly negatively charged)Biochemical Properties
- •Solubility: Highly soluble in water and physiological saline (>250 mg/mL at 25°C)
- •pH Stability: Optimal stability in pH 6.0-7.5 range; more acid-stable than KED tripeptide
- •Thermal Stability: Degradation increases significantly above 35°C; optimal at 2-8°C
- •Form: White to off-white lyophilized (freeze-dried) powder
- •Purity: ≥95% HPLC verified (typical commercial grade)
- •Shelf-life: 24-36 months when stored at 2-8°C in darkness
- •Hygroscopicity: Powder absorbs moisture; store in desiccated conditions with desiccant packets
Role of Glycine in Cartilage
Glycine, the fourth amino acid in Sigumir, is specifically included because:
1. Collagen Triple-Helix Requirement: Glycine comprises ~33% of all collagen molecules; every third residue in collagen is glycine. Its small size permits the tight packing of the collagen triple helix.
2. Cartilage Matrix Structure: Cartilage is >90% type II collagen by dry weight. Enhanced glycine availability or signaling may support collagen biosynthesis and cross-linking.
3. Glycine Receptor Signaling: Glycine acts as an inhibitory neurotransmitter and also binds glycine receptors on chondrocytes, potentially modulating anabolic and catabolic gene expression.
4. Anti-inflammatory Role: Glycine signaling through GlyR1 receptors can suppress pro-inflammatory cytokine production in immune cells and chondrocytes.
Comparison to Cartalax and Other Cartilage Bioregulators
Sigumir vs. Cartalax (EDR tripeptide)
| Aspect | Sigumir (KEDG) | Cartalax (EDR) | Notes |
|---|---|---|---|
| Amino Acids | 4 (KEDG) | 3 (EDR) | Sigumir adds glycine for collagen specificity |
| Molecular Weight | 464.47 g/mol | ~381.41 g/mol | Sigumir slightly larger |
| Target Tissue | Cartilage + joint matrix | Cartilage (broader) | KEDG more tissue-specific |
| Glycine Role | Collagen synthesis support | Absent | KEDG includes collagen-promoting glycine |
| Published Studies | 15+ in Russian literature | 10+ in Russian literature | Sigumir has slightly more clinical data |
| Clinical Approval | Russia (investigational) | Russia (approved) | Cartalax more established clinically |
| Cost (research) | $25-50/2mg | $20-40/2mg | Similar pricing |
Sigumir vs. BPC-157
BPC-157 (pentadecapeptide, Body Protection Compound-157) is widely studied for joint repair but differs significantly from Sigumir:
| Feature | Sigumir (KEDG) | BPC-157 |
|---|---|---|
| Size | Tetrapeptide (4 AA) | Pentadecapeptide (15 AA) |
| Origin | Synthetic bioregulator | Gastric cytoprotective peptide |
| Specificity | Cartilage-targeted | Broad tissue repair |
| Mechanism | Epigenetic/transcriptional | Growth factor enhancement (VEGF, FGF) |
| Joint Application | Cartilage matrix support | Tendon, ligament, bone healing |
| BBB Penetration | Minimal | Excellent (oral, intranasal) |
| Clinical Data | Russian research | Eastern European + Western studies |
| Cost | $25-50/2mg | $30-60/5mg |
Complementary Applications: Some research suggests combining Sigumir (for cartilage matrix) with BPC-157 (for systemic repair signaling) may have synergistic effects on joint healing.
Sigumir vs. TB-500 (Thymosin Beta-4)
TB-500 is a 43-amino acid polypeptide used for tissue repair, with a different mechanism than Sigumir:
| Feature | Sigumir (KEDG) | TB-500 |
|---|---|---|
| Size | Tetrapeptide (4 AA) | Polypeptide (43 AA) |
| Mechanism | Epigenetic/transcriptional | Actin sequestration; growth factor signaling |
| Tissue Specificity | Cartilage-targeted | Broad (muscle, bone, connective tissue) |
| Inflammation | Suppresses pro-inflammatory | Suppresses pro-inflammatory; promotes remodeling |
| Collagen Effect | Direct (KEDG) | Indirect (through growth factors) |
| Joint Applications | Cartilage preservation | Tendon/ligament injury, broad joint repair |
| Stability | Stable; easy synthesis | Relatively stable; larger molecule |
| Cost | $25-50/2mg | $50-100/5mg |
Differentiation: Sigumir targets cartilage-specific matrix preservation, while TB-500 is better suited for tendon/ligament injury and broad connective tissue repair.
Mechanism of Action: Cartilage-Specific Regulation
1. Chondrocyte Chromatin Remodeling
Sigumir operates through several interrelated mechanisms targeting cartilage cell populations:
Histone Acetylation in Cartilage:
- •Increases histone acetyl-transferase (HAT) activity specifically in chondrocytes
- •Promotes local histone acetylation at promoters of cartilage-specific genes (COL2A1, aggrecan, COMP, SOX9)
- •Results in "open" chromatin architecture in cartilage extracellular matrix (ECM) genes
- •Enhanced transcriptional accessibility for chondrocyte-specific transcription factors (SOX9, RUNX2)
Transcription Factor Recruitment:
- •Enhances binding of SOX9 (SRY-box transcription factor 9) to cartilage-specific enhancers
- •Stabilizes RUNX2 binding at osteochondrocyte differentiation genes (preventing terminal differentiation)
- •Increases C/EBPβ (CCAAT/enhancer-binding protein beta) recruitment at MMP-suppressing promoters
- •Upregulates chondrocyte master regulators while suppressing hypertrophic differentiation
2. Collagen Synthesis and Matrix Deposition
Sigumir promotes cartilage extracellular matrix production through multiple pathways:
COL2A1 Gene Activation:
- •Upregulates type II collagen (COL2A1) mRNA expression in chondrocytes
- •Enhances type II collagen protein synthesis 1.5-2 fold in culture models
- •Promotes proper collagen chain folding and hydroxylation through prolyl hydroxylase upregulation
- •Supports collagen cross-linking enzyme expression (lysyl oxidase, transglutaminases)
Aggrecan and COMP Upregulation:
- •Increases aggrecan (cartilage proteoglycan core protein) synthesis
- •Enhances cartilage oligomeric matrix protein (COMP) expression, which stabilizes collagen
- •Improves cartilage matrix hydration and mechanical properties through enhanced GAG content
Glycine's Specific Role:
- •Glycine incorporation into collagen triple helix is enhanced when glycine signaling is active
- •Glycine receptor (GlyR) activation on chondrocytes may upregulate collagen synthesis genes
- •Improved collagen cross-linking and matrix stability through enhanced glycine availability
3. Inflammatory Cytokine Modulation
Pro-Inflammatory Suppression:
- •Decreases IL-6, TNF-α, and IL-1β production in inflamed cartilage
- •Reduces NF-κB p65 phosphorylation (downstream inflammatory signaling)
- •Suppresses COX-2 and iNOS expression (prostaglandin and nitric oxide production)
Anti-Inflammatory Promotion:
- •Enhances IL-10 and TGF-β expression (immunoregulatory cytokines)
- •Increases cartilage-protective IL-4 and IL-13 production
- •Shifts microenvironment from catabolic to anabolic
Matrix Metalloproteinase (MMP) Suppression:
- •Reduces MMP-9 and MMP-13 expression (MMPs drive cartilage degradation)
- •Increases tissue inhibitors of metalloproteinases (TIMPs), which block MMP activity
- •Restores balance between matrix synthesis and catabolism
4. Senescence Reduction in Chondrocytes
Senescence Marker Suppression:
- •Decreases p16INK4a and p21Cip1 expression in aging chondrocytes
- •Reduces senescence-associated secretory phenotype (SASP) factor production
- •Improves chondrocyte proliferative capacity in aged cartilage
Stress Resistance:
- •Enhances antioxidant enzyme expression (SOD2, catalase, GPx)
- •Reduces ROS-induced chondrocyte death under inflammatory stress
- •Improves cellular energy (ATP) production through mitochondrial optimization
Published Research and Clinical Evidence
Key Peer-Reviewed Studies
- Summary: KEDG peptide administration to aged rats with induced osteoarthritis resulted in reduced cartilage degradation and improved cartilage thickness compared to controls.
- Summary: Lifespan extension study showing KEDG peptide and related bioregulators extended median lifespan by 18-24% in mouse models; also reduced joint degeneration markers.
- Summary: Comprehensive review of tissue-specific peptides in aging; discusses cartilage peptides in context of joint aging and osteoarthritis.
- Summary: Mechanistic study showing KEDG peptide increases COL2A1 and aggrecan expression in primary chondrocytes through epigenetic mechanisms.
- Summary: Review discussing Sigumir's role in osteoarthritis research and cartilage regeneration mechanisms.
- Summary: Study of KEDG peptide in human cartilage explants showing dose-dependent protection against IL-1β-induced degradation.
Research Protocols and Dosing
In Vitro Protocol (Chondrocyte Culture)
Materials:
- •Primary bovine chondrocytes or mouse ATDC5 cells
- •DMEM/F12 medium with 10% fetal bovine serum (FBS)
- •Sigumir (dissolved in PBS, final concentration range 10 nM—10 μM)
- •IL-1β (recombinant, 10 ng/mL) — to induce inflammatory response
- •Serum-free medium for gene expression studies
Protocol:
1. Plate chondrocytes at 1×10^5 cells/well in 24-well plates
2. Pre-treat with Sigumir concentrations (10 nM, 100 nM, 1 μM, 10 μM) for 2 hours
3. Stimulate with IL-1β (10 ng/mL) for 48-72 hours
4. Assess endpoints:
- Gene expression: qRT-PCR for COL2A1, aggrecan, COMP, SOX9, MMP-9, MMP-13, IL-6, TNF-α
- Protein levels: ELISA for pro-inflammatory cytokines
- Matrix production: GAG measurement (DMMB assay), hydroxyproline assay for collagen
- Cell viability: MTT assay or live-dead staining
- ROS measurement: DCFDA fluorescence assay
Cartilage Explant Model (Ex Vivo)
Materials:
- •Bovine or human articular cartilage explants (3-4mm diameter, 2mm thick)
- •Serum-free DMEM/F12 medium
- •Sigumir (1-10 μM range)
- •IL-1β or TNF-α (inflammatory stimulus)
Protocol:
1. Incubate cartilage explants in medium containing Sigumir
2. Stimulate with IL-1β to induce cartilage degradation
3. Culture for 7-14 days
4. Measure:
- GAG loss: DMMB assay (sulfated glycosaminoglycans in media)
- Collagen leaching: hydroxyproline assay
- Histology: Safranin-O staining (proteoglycan content), collagen immunostaining
- Gene expression: qRT-PCR on cartilage tissue
In Vivo Protocol (Animal Model)
Model System: Aged female C57BL/6 mice (18-20 months old) or Dunkin Hartley guinea pigs (osteoarthritis-prone)
OA Induction: Destabilization of medial meniscus (DMM) or monosodium iodoacetate (MIA) injection
Treatment:
- •Intra-articular injection of Sigumir (10 μg/joint in 10 μL PBS) or systemic IP injection (0.5-1 mg/kg)
- •Dosing schedule: 2x per week for 8 weeks
- •Positive control: Indomethacin (NSAID) or hyaluronic acid injection
Assessment (at week 8 post-treatment):
- •Cartilage histology: Safranin-O/Fast Green staining; OARSI (Osteoarthritis Research Society International) scoring
- •Joint imaging: Micro-CT for osteophyte formation and bone changes
- •Biochemical markers: Serum CTX-II (type II collagen breakdown product), COMP, hyaluronic acid
- •Gene expression: qRT-PCR from cartilage tissue for COL2A1, aggrecan, MMP-9, IL-6
Recommended Dosing Ranges for Research
| Route | Dose Range | Frequency | Duration | Notes |
|---|---|---|---|---|
| Intraperitoneal (IP) | 0.5-1 mg/kg | 2-3x/week | 4-8 weeks | Systemic availability |
| Subcutaneous (SC) | 0.5-1 mg/kg | 2-3x/week | 4-8 weeks | Slower absorption |
| Intra-articular (IA) | 10-100 μg/joint | 1-2x/week | 4-8 weeks | Direct joint delivery; preferred for OA |
| In vitro | 10 nM—10 μM | Single/repeated dose | 24-72 hours | 100 nM—1 μM typical effective range |
Safety Profile and Toxicology
Preclinical Safety Data
- •Acute toxicity (LD50): Not established; no lethality at ≤100 mg/kg (mice, rats)
- •Chronic toxicity: 12-24 month studies in rodents showed no organ toxicity or histopathological changes at doses ≤5 mg/kg
- •Genotoxicity: No mutagenic potential in Ames test; no aberrant chromosomes in micronucleus assay
- •Immunogenicity: No antibody formation or immune activation in repeated-dose studies
- •Biocompatibility: Intra-articular administration showed excellent local tolerance with no synovitis or inflammatory response
Clinical Experience (Russian Research)
Over 20+ years of Russian research:
- •Adverse events: Minimal; no systemic toxicity reported
- •Local reactions: Mild transient pain at IP/SC injection site (if applicable)
- •Long-term safety: No evidence of tolerance, tachyphylaxis, or cumulative toxicity
Storage and Stability
- •Optimal storage: 2-8°C in sealed vials, protected from light
- •Long-term storage: -20°C extends shelf-life to 36+ months
- •Reconstitution: Dissolve in sterile PBS or normal saline immediately before use
- •Post-reconstitution stability: Use within 24 hours if refrigerated; within 4 hours at room temperature
- •Avoid: Repeated freeze-thaw cycles; direct exposure to light
Applications in Joint Research
Osteoarthritis Models
Sigumir research addresses OA mechanisms through:
- •Studying cartilage matrix preservation in aging joints
- •Investigating inflammatory modulation in OA progression
- •Exploring epigenetic reversibility in chondrocyte senescence
Sports Medicine and Injury Recovery
Preliminary research suggests applications in:
- •Acute joint trauma and cartilage injury repair
- •Post-surgical cartilage recovery (e.g., ACL reconstruction)
- •Cartilage preservation in high-impact athletes
Age-Related Joint Degeneration
- •Application in pre-clinical models of aging-associated joint stiffness
- •Investigation of senescence markers in aged cartilage
- •Evaluation of longevity-span enhancement in joint tissue
Frequently Asked Questions
Q: How is Sigumir different from other Khavinson peptides?
A: Each Khavinson bioregulator targets specific tissues through tissue-specific amino acid sequences. Sigumir targets cartilage (KEDG); Semax targets the brain; Ovagen targets reproductive tissue. The KEDG sequence plus glycine was identified through analysis of cartilage tissue peptide profiles.
Q: Can Sigumir be combined with NSAIDs or other joint therapies?
A: In research settings, yes. Preliminary data suggest Sigumir may have complementary anti-inflammatory effects with NSAIDs. Animal model data supports co-treatment safety; clinical combination studies are limited.
Q: What is the half-life of Sigumir in circulation?
A: Estimated at 10-20 minutes in serum (typical for tetrapeptides). However, tissue accumulation in cartilage may extend effective half-life. This has not been formally studied; intra-articular delivery is preferred for local joint effects.
Q: Is Sigumir approved for use in humans with arthritis?
A: No. Sigumir is currently an investigational compound. Clinical trials have been small and limited to Russia. It is not approved by the FDA or EMA and should only be used in research contexts.
Q: How does Sigumir's cost compare to other joint repair peptides?
A: Sigumir typically costs $25-50 per 2mg vial in research settings. This is comparable to Cartalax (~$20-40) but significantly less than TB-500 ($50-100/5mg) or BPC-157 ($30-60/5mg).
Q: Can Sigumir penetrate cartilage tissue after systemic administration?
A: Research suggests limited systemic cartilage penetration; intra-articular injection achieves higher local concentrations. Glycosaminoglycans in cartilage matrix may impede peptide diffusion, making direct joint delivery preferable.
Conclusion
Sigumir represents a promising avenue for investigating cartilage-specific epigenetic regulation and joint degeneration mechanisms. As part of Professor Khavinson's broader body of work on bioregulatory peptides, Sigumir offers researchers a tool for studying chondrocyte senescence, matrix dynamics, and cartilage preservation. The published evidence, primarily from Russian sources, demonstrates mechanistic plausibility and preliminary efficacy in animal models and ex vivo cartilage studies.
The inclusion of glycine in the KEDG sequence makes Sigumir particularly suited for collagen-focused cartilage research, distinguishing it from broader-spectrum peptides like BPC-157 or TB-500. Future research priorities include large-scale Western clinical trials in osteoarthritis, mechanistic studies of the KEDG sequence's cartilage-specificity, and investigation of combination approaches with established joint therapies or other tissue-repair peptides.
The peptide's favorable safety profile, ease of synthesis, tissue-specific targeting, and potential for intra-articular delivery make it a valuable research tool in gerontology, rheumatology, and sports medicine.
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For research purposes only. Not for human use.