Background

An intragastric satiety-inducing device (ISD) is a minimally invasive approach to induce satiety by continuously pressing the stomach and stimulating ghrelin-producing cells. Photodynamic therapy (PDT) can be combined by generating singlet oxygen under laser irradiation to enhance the effects of ISD. This study aimed to investigate the efficacy and safety of PDT plus ISD to suppress weight gain in a mini pig. Characteristics of chlorin e6 (Ce6), photosensitizer for PDT, samples were evaluated including photo-responsive cell death. Ce6 was conjugated with polymer to homogeneously coat on the disk portion of the ISD. Twelve mini pigs were randomized into control, single PDT, ISD, and ISD plus PDT groups with three in each. The therapeutic effectiveness was assessed by comparing weight changes, hormone levels, and histological examination. Cell death increased 3.2-fold at concentration of 5 µg/mL compared to the absence of laser irradiation. All ISD migrated into the stomach at 2-3 weeks. The results of study, ISD plus PDT proved to be the most effective for wight loss. Their changes of body weight (control: 28% vs ISD plus PDT: 4%, p < 0.001), ghrelin (control: 4% vs ISD plus PDT: -35%, p < 0.001) and leptin levels (control: 8% vs ISD plus PDT: 35%, p < 0.001) were significantly affected. Histological examination results were similar. Photoreactive ISD can be easily accessed via minimally invasive approach and effectively stimulated ghrelin producing cells. Combination therapy was safe and effective to suppress weight gain by reducing ghrelin hormone secretion in a mini pig model.