Photoacoustic molecular imaging for microvascular system in browning adipose tissues

At present, approximately one third of adults worldwide are obese or overweight. The phenomenon of adipose browning, that is, adipocyte trans-differentiation from an energy storage role to a heat production role, opens up a new way to reverse obesity. However, current methods for judging whether adipose browning occurs are usually based on invasive histological assessments. Adipose browning has been found to be accompanied by changes in adipose microvascular system. Therefore, our research focused on the above biological feature and used a non-invasive photoacoustic imaging technique that integrates the advantages of optical and acoustic imaging to visualize adipose microvascular system in obese mice treated with cold stimulation in a three-dimensional mode. The results showed that based on hemoglobin components, photoacoustic molecular imaging could not only accurately visually display a full view of increased arteriovenous blood network and enhanced blood oxygen consumption during adipose browning, but also quantitatively analyze it. Moreover, the data was consistent with the results of histological means including hematoxylin-eosin staining and immunofluorescence staining. In summary, we demonstrated the feasibility of photoacoustic molecular imaging for detecting adipose browning. This work will provide a new possibility for non-invasive assessment of adipose browning, which can help researchers and clinicians fight against obesity.