How organs react under fasting or glucose-insulin status: a self-controlled study using ¹⁸F-FDG total-body PET/CT

Area of Science:

• Nuclear medicine and metabolic imaging
• Cardiovascular disease research
• Systemic metabolism

Background:

• Ischemic cardiomyopathy (ICM) affects cardiac function and systemic metabolism.
• Understanding organ-specific glucose metabolism is crucial for managing ICM.
• Diabetes mellitus (DM) further complicates metabolic alterations in ICM.

Purpose of the Study:

• To investigate organ-specific glucose metabolism in ICM patients.
• To analyze inter-organ metabolic network alterations under fasting and glucose/insulin loading.
• To compare metabolic responses between diabetic and non-diabetic ICM patients.

Main Methods:

• Prospective, self-controlled study using total-body ¹⁸F-FDG PET/CT scans.
• Measurement of SUV_mean in 24 predefined regions of interest (ROIs) under fasting (FAST) and glucose/insulin (G/I) conditions.
• Assessment of metabolic network connectivity using mutual information analysis, stratified by DM status.

Main Results:

• Non-DM patients showed significant decreases in peripheral and brain glucose uptake and enhanced metabolic network connectivity from FAST to G/I.
• DM patients exhibited blunted glucose uptake changes and disrupted metabolic network connectivity, with impaired brain-peripheral interactions.
• Smoking and older age correlated with stronger inter-organ connectivity in both DM and non-DM groups.

Conclusions:

• Organ-specific metabolic profiles and inter-organ networks differ between fasting and glucose/insulin loading states in ICM.
• Diabetic ICM patients display attenuated metabolic responses and network changes compared to non-diabetic patients.
• Metabolic network alterations in ICM are influenced by diabetes status, age, and smoking.