A team led by Prof. Tzu-Ming LIU at the University of Macau (UM) Faculty of Health Sciences (FHS) has developed a technology for prediabetes detection based on metabolic fluorescence imaging of adipose tissue. The study presents an innovative method for diagnosing prediabetes, shedding light on diabetes prevention strategies. The research has been published in the international journal Theranostics.

Prediabetes can be reversed through lifestyle intervention, but its main pathologic hallmark, insulin resistance (IR), cannot be detected as conveniently as blood glucose testing. In consequence, the diagnosis of prediabetes is often delayed until patients have hyperglycemia. Therefore, developing a less invasive diagnostic method for rapid IR evaluation will contribute to the screening and prevention of prediabetes. Since adipose tissue is an endocrine organ that plays a crucial role in the development and progression of prediabetes, metabolic imaging the prediabetic microenvironment of adipose tissues provides a less invasive alternative for the characterization of IR and inflammatory pathology.

The research team successfully identified the differentiable features of prediabetic adipose tissues by employing the metabolic imaging of three endogenous fluorophores NAD(P)H, FAD, and lipofuscin pigments. 1040-nm excited lipofuscin autofluorescence could mark the location of macrophages. This unique feature helps separate the metabolic fluorescence signals of macrophages from those of adipocytes. In prediabetes fat tissues with IR, we found only adipocytes exhibited a low redox ratio of metabolic fluorescence and high free NAD(P)H fraction a1. This differential signature disappears and recover from IR. When mice have diabetic hyperglycemia and inflamed fat tissues, both adipocytes and macrophages possess this kind of metabolic change. As confirmed with RNA-seq analysis and histopathology evidence, the change in adipocyte’s metabolic fluorescence could be an indicator or risk factor of prediabetic IR. This study provides an innovative approach to diagnose prediabetes, which sheds light on the strategy for diabetes prevention.

The project was supported by the Science and Technology Development Fund, Macao SAR (file number: 122/2016/A3, 018/2017/A1, 0011/2019/AKP, 0002/2021/AKP; 0007/2021/AKP, 0120/2020/A3, 0026/2021/A) and UM’s research fund (file number: MYRG2018-00070-FHS, MYRG-CRG2022-00009-FHS). The full version of the research article can be viewed at https://www.thno.org/v13p3550.htm

The metabolic fluorescence features of healthy, prediabetic, and diabetic adipose tissues. These features can be used for differential diagnosis of diabetes.