Imaging Hydrogen Sulfide in Hypoxic Tissue with [^99mTc]Tc-Gluconate

Area of Science:

• Biomedical Imaging
• Molecular Imaging
• Radiochemistry

Background:

• Hydrogen sulfide (H2S) is a crucial gasotransmitter implicated in various physiological and pathological processes, including hypoxia and cancer.
• Endogenous H2S production is elevated in hypoxic conditions, presenting a potential target for diagnostic imaging.
• Previous work established [99mTc]Tc-gluconate as a potential agent for imaging endogenous H2S.

Purpose of the Study:

• To evaluate the efficacy of [99mTc]Tc-gluconate for detecting endogenous H2S generated in hypoxic tissues.
• To assess the performance of [99mTc]Tc-gluconate in both in vitro and in vivo models of hypoxia.

Main Methods:

• In vitro experiments utilized the CT26 colon carcinoma cell line under hypoxic and normoxic conditions to measure [99mTc]Tc-gluconate uptake.
• An in vivo hindlimb ischemia-reperfusion model was established in BALB/c mice.
• SPECT/CT imaging was performed after intravenous injection of [99mTc]Tc-gluconate to analyze uptake in ischemic and normal limbs.

Main Results:

• In vitro, [99mTc]Tc-gluconate uptake was significantly higher in hypoxic CT26 cells compared to normoxic cells.
• In vivo SPECT/CT imaging revealed a fivefold increase in [99mTc]Tc-gluconate uptake in the ischemic limb versus the normal limb.
• The mean standard uptake value (SUVmean) was 0.39 ± 0.03 in the ischemic limb and 0.07 ± 0.01 in the normal limb.

Conclusions:

• [99mTc]Tc-gluconate is a novel and effective imaging agent for detecting endogenous H2S.
• The agent demonstrates utility for both in vitro and in vivo imaging of H2S in hypoxic tissues.
• This finding supports the potential clinical application of [99mTc]Tc-gluconate in diagnosing and monitoring conditions associated with tissue hypoxia.