Stem cell therapy affords optimism for incurable bladder diseases including interstitial cystitis/bladder pain syndrome (IC/BPS). IC/BPS is a chronic disease caused by various etiological factors and pelvic pain is one of its serious symptoms. Although several treatment options are available, they are not reliable, and many patients experience treatment-associated mortality, or persistent or recurrent symptoms. Therefore, the application of stem cells in IC/BPS therapy has garnered the scientific attention recently. Here, we investigate the therapeutic potential of Wharton’s jelly stem cells (WJ-MSC-EVs) and the derived extracellular vesicles (EVs) (WJ-MSC-EVs) that prepared using advanced three-dimensional dynamic culture method (a3D-EVs) and using exogenous TGF-β3 treatment (T-a3D-EVs) in IC/BPS mouse model.

Here, we produced EVs from Wharton’s jelly MSCs (WJ-MSCs) using advanced three-dimensional (3D) culture (a3D-EVs) and the addition of exogenous transforming growth factor-β3 (TGF-β3) (T-a3D-EVs). Treatment with T-a3D-EVs led to significantly enhanced wound healing capacity in human urothelial cells and anti-inflammatory activity in lipopolysaccharide (LPS)-activated macrophages. We then verified the therapeutic effect of T-a3D-EVs in vivo using the protamine sulfate (PS)/LPS-induced murine model of IC/BPS.

Importantly, intramural injection of T-a3D-EVs in vivo resulted in restoration of bladder function, superior anti-inflammatory activity, and recovery of damaged urothelium compared to treatment with a3D-EVs or MSCs. Interestingly, we detected increased TGF-β1 in T-a3D-EVs, which might be involved in the anti-inflammatory activity of these EVs.

In our study, we administered local injections of EVs directly into the bladder wall and observed the therapeutic capacity of these EVs against IC/BPS-associated lesions in a murine model. Regarding the role of signaling pathways, T-a3D-EVs showed a marked increase in the phosphorylation of AKT. In this regard, a previous report showed the anti-inflammatory activity of the PI3K/AKT signaling pathway in LPS-mediated inflammatory effects. Moreover, the crosstalk between the TGF-β signaling pathway and PI3K/AKT signaling has been reported previously . However, further study is essential for in-depth understanding of the interplay between TGF-β and PI3K/AKT signaling and its impact on the in vitro and in vivo anti-inflammatory activities. The close relationship between TGF-β and bladder pathophysiology has been reviewed elsewhere, and in-depth investigation on the connection between TGF-β1 and T-a3D-EV-associated therapeutic capacities is required in future studies.

Taken together, we demonstrate the excellent immune-modulatory and regenerative abilities of T-a3D-EVs as observed by recovery from inflammation and urothelial damage, which could be a promising therapeutic strategy for IC/BPS. In summary, our study demonstrates a novel approach for qualitative as well as quantitative EV production for IC/BPS therapy, which could be a robust tool for clinical application in bladder disease therapy in humans in the future.