Recombinant Human IGF-I sR

Recombinant Human IGF-I sR is used in research applications primarily to study and modulate cellular growth, differentiation, and tissue regeneration, especially in contexts where endogenous IGF-I signaling is deficient or requires precise control.

Key scientific reasons to use recombinant human IGF-I sR include:

• Bone Formation and Regeneration: IGF-I plays a critical role in osteoblastogenesis and bone formation. Recombinant human IGF-I has been shown to significantly enhance new bone formation in aged animal models, both when delivered locally and systemically. Local delivery is particularly advantageous as it improves bone regeneration without increasing circulating IGF-I levels, thereby minimizing systemic side effects such as increased cancer risk.

• Tissue Repair and Regeneration: IGF-I is a potent anabolic factor for various tissues, including muscle and tendon. It promotes cellular proliferation, differentiation, and matrix synthesis, making it valuable for studies on tissue engineering and regenerative medicine.

• Growth and Metabolic Regulation: Recombinant IGF-I can restore normal growth and metabolic function in models of IGF-I deficiency. It has been shown to improve linear growth, insulin sensitivity, and normalize circulating growth hormone (GH), IGF-binding proteins (IGFBPs), and insulin levels.

• Disease Modeling and Therapeutic Testing: Recombinant IGF-I is used to model diseases such as osteoporosis, growth retardation, and insulin resistance, and to evaluate potential therapeutic interventions targeting the IGF axis.

• Cell Signaling Studies: IGF-I binds to IGF-I receptor, IGF-II receptor, and the insulin receptor, activating downstream signaling pathways involved in cell survival, proliferation, and differentiation. Recombinant IGF-I is essential for dissecting these pathways in vitro and in vivo.

• Controlled Experimental Conditions: Using recombinant IGF-I allows for precise dosing, timing, and localization in experimental systems, which is critical for reproducibility and mechanistic studies.

Best practices for using recombinant human IGF-I sR in research:

• Select appropriate delivery methods (local vs. systemic) based on experimental goals and risk of off-target effects.
• Use validated bioassays to quantify biological activity and downstream effects.
• Consider species-specific responses and receptor interactions when designing experiments.

In summary, recombinant human IGF-I sR is a versatile tool for investigating and manipulating IGF-I–mediated biological processes, with applications spanning bone biology, tissue regeneration, metabolic regulation, and disease modeling.

You can use recombinant human IGF-I sR as a standard for quantification or calibration in your ELISA assays, but only under specific conditions: the ELISA must be validated to recognize the recombinant form, and the standard must be comparable to the analyte in your samples in terms of structure and immunoreactivity.

Key considerations:

• ELISA specificity: Many commercial ELISA kits are designed to detect native (endogenous) IGF-I sR, not necessarily the recombinant form. If your ELISA is validated for recombinant IGF-I sR, or if the antibodies used in the assay recognize both native and recombinant forms equivalently, then recombinant IGF-I sR can be used as a standard.
• International standards: The World Health Organization (WHO) and NIBSC provide recombinant human IGF-I standards (e.g., NIBSC 02/254) specifically intended for calibration of immunoassays, including ELISA. Using such a standard ensures traceability and comparability across assays.
• Validation: If you use a recombinant standard, you must validate that the standard curve generated with recombinant IGF-I sR is parallel to the curve generated with native IGF-I sR in your samples, confirming equivalent immunoreactivity. This is essential for accurate quantification.
• Documentation: Some ELISA kits explicitly state that their standards are recombinant proteins and reference international standards for calibration. Always check your kit documentation to confirm compatibility.

Best practices:

• Use a recombinant standard that matches the isoform and post-translational modifications of the analyte in your samples as closely as possible.
• Validate the assay’s performance (linearity, recovery, precision) using the recombinant standard in your specific sample matrix.
• If available, use a recombinant standard that is traceable to an international reference preparation (e.g., WHO/NIBSC 02/254).

Summary:
You can use recombinant human IGF-I sR as a standard for ELISA quantification if your assay is validated for this purpose and the recombinant standard is comparable to the analyte in your samples. For highest accuracy and comparability, use a recombinant standard traceable to an international reference and confirm assay performance through validation experiments.

Based on the provided search results, there is no specific information about the validated applications for Recombinant Human IGF-I sR (soluble receptor) in published research. The results mention the IGF-1 receptor's role in regulating lifespan and cell survival, but they do not detail experimental or clinical applications for which the IGF-I sR itself has been validated in peer-reviewed studies. For precise validation data, consulting the product datasheet or relevant scientific literature directly referencing Recombinant Human IGF-I sR would be necessary.

To reconstitute and prepare Recombinant Human IGF-I sR protein for cell culture experiments, follow these best-practice steps:

1. Centrifuge the vial: Briefly spin the lyophilized protein vial in a microcentrifuge to ensure all material is at the bottom before opening.

2. Choose an appropriate solvent:

   • Most protocols recommend sterile water or sterile PBS for reconstitution.
   • For enhanced stability and to minimize adsorption, add 0.1% carrier protein such as endotoxin-free recombinant human serum albumin (HSA) or bovine serum albumin (BSA).
   • Some protocols suggest using 10 mM acetic acid with 0.1% HSA for improved solubility, especially if the protein is difficult to dissolve.

3. Reconstitution concentration:

   • Typical concentrations range from 0.1 mg/mL to 1.0 mg/mL.
   • For example, dissolve 100 μg of protein in 1 mL for 0.1 mg/mL, or in 100 μL for 1 mg/mL.

4. Mix gently:

   • Do not vortex. Gently swirl or tap the vial to dissolve the protein.
   • Allow the solution to sit at room temperature for 15–30 minutes with gentle agitation to ensure complete dissolution.

5. Aliquot and storage:

   • After reconstitution, aliquot the solution to avoid repeated freeze-thaw cycles.
   • Store aliquots at –20°C or –80°C for long-term storage (up to 6–12 months), or at 4°C for short-term use (up to 1 week).
   • Avoid storing in frost-free freezers and do not store diluted working solutions for extended periods.

6. Preparation for cell culture:

   • Before use, dilute the reconstituted stock to the desired working concentration in your cell culture medium.
   • Ensure all solutions are sterile and endotoxin-free to prevent adverse effects on cells.

Summary Table: Key Steps and Conditions

Additional notes:

• Always consult the specific product datasheet or Certificate of Analysis for any unique requirements for your IGF-I sR preparation.
• If solubility issues occur, allow the solution to incubate at 4°C overnight.
• Confirm protein integrity by SDS-PAGE if needed.

These steps will ensure optimal activity and reproducibility in your cell culture experiments.