Structural determinants of beta-cell failure in type 2 diabetes: a multimodality imaging study

Area of Science:

• Endocrinology
• Metabolic Diseases
• Medical Imaging

Background:

• Type 2 diabetes (T2D) is associated with reduced pancreatic volume and beta-cell mass, but the causal relationship remains unclear.
• Intra-pancreatic fat deposition (IPFD) is increasingly recognized as a factor in metabolic dysfunction.

Purpose of the Study:

• To investigate the relationship between pancreatic volume, beta-cell mass, beta-cell function, and T2D risk.
• To determine if IPFD modifies these associations in individuals at risk for or with T2D.

Main Methods:

• Utilized PET/CT imaging to correlate beta-cell mass with pancreatic volume, IPFD, and beta-cell function (HOMA2-%B) in 52 individuals.
• Analyzed cross-sectional data from UK Biobank (N=25,212) to assess T2D prevalence based on pancreatic volume and IPFD categories derived from MRI.
• Conducted a 6-year longitudinal case-cohort study (N=2168) using CT imaging to evaluate pancreatic volume and IPFD as predictors of incident T2D.

Main Results:

• Smaller pancreatic volume and higher IPFD were associated with reduced beta-cell mass and lower insulin secretion in the PET/CT study.
• Individuals with a small pancreas and high IPFD exhibited the highest likelihood of T2D in the UK Biobank cohort (aOR=1.71).
• Longitudinal analysis confirmed that a small/high-fat pancreas significantly increased T2D risk (aHR=3.12) compared to a large/low-fat pancreas.

Conclusions:

• A combination of a small pancreas and high intra-pancreatic fat deposition represents a distinct structural phenotype.
• This phenotype is strongly associated with an increased risk of developing type 2 diabetes.
• The findings support the role of beta-cell failure in the pathogenesis of T2D, influenced by pancreatic structure and fat content.