Hydrogen Sulfide Delivery to Enhance Bone Tissue Engineering Cell Survival

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Cell Biology

Background:

• High local calcium (Ca2+) and phosphate (Pi) concentrations are vital for bone healing but can become cytotoxic.
• This cytotoxicity leads to mitochondrial dysfunction, oxidative stress, and cell death in mesenchymal stem cells (MSCs).
• Hydrogen sulfide (H2S) shows potential as a cytoprotective agent to improve MSC tolerance in bone tissue engineering.

Purpose of the Study:

• To evaluate the cytoprotective effects of H2S on MSCs exposed to cytotoxic Ca2+/Pi concentrations.
• To determine the optimal concentration of a fast-releasing H2S donor (NaSH) for MSC proliferation.
• To synthesize and assess a novel sustained-release H2S donor (thioglutamic acid-GluSH) for bone regenerative applications.

Main Methods:

• Assessed MSC proliferation and differentiation under varying NaSH concentrations.
• Determined the cytotoxic limit of NaSH for MSCs.
• Synthesized GluSH and characterized its H2S release profile over 7 days.
• Evaluated MSC viability and osteogenic differentiation in the presence of cytotoxic Ca2+/Pi and GluSH.

Main Results:

• A NaSH concentration of 1 mM enhanced MSC proliferation and differentiation, with a toxicity limit observed at 4 mM.
• The novel donor molecule, GluSH, successfully released H2S at cytoprotective levels for 7 days.
• MSCs cultured with cytotoxic Ca2+/Pi and GluSH demonstrated enhanced survival and osteogenic differentiation.

Conclusions:

• H2S, particularly from sustained donors like GluSH, can protect MSCs from cytotoxic ion concentrations.
• GluSH shows promise for incorporation into calcium phosphate (CaP)-based bone graft substitutes.
• This approach offers a viable strategy for enhancing bone regeneration in complex applications.