Hydrogel-exosome system in tissue engineering: A promising therapeutic strategy.

Characterized by their pivotal roles in cell-to-cell communication, cell proliferation, and immune regulation during tissue repair, exosomes have emerged as a promising avenue for "cell-free therapy" in clinical applications. Hydrogels, possessing commendable biocompatibility, degradability, adjustability, and physical properties akin to biological tissues, have also found extensive utility in tissue engineering and regenerative repair. The synergistic combination of exosomes and hydrogels holds the potential not only to enhance the efficiency of exosomes but also to collaboratively advance the tissue repair process. This review has summarized the advancements made over the past decade in the research of hydrogel-exosome systems for regenerating various tissues including skin, bone, cartilage, nerves and tendons, with a focus on the methods for encapsulating and releasing exosomes within the hydrogels. It has also critically examined the gaps and limitations in current research, whilst proposed future directions and potential applications of this innovative approach.

UPK3A+ umbrella cell damage mediated by TLR3-NR2F6 triggers programmed destruction of urothelium in Hunner-type interstitial cystitis/painful bladder syndrome.

Urothelial damage and barrier dysfunction emerge as the foremost mechanisms in Hunner-type interstitial cystitis/bladder pain syndrome (HIC). Although treatments aimed at urothelial regeneration and repair have been employed, their therapeutic effectiveness remains limited due to the inadequate understanding of specific cell types involved in damage and the lack of specific molecular targets within these mechanisms. Therefore, we harnessed single-cell RNA sequencing to elucidate the heterogeneity and developmental trajectory of urothelial cells within HIC bladders. Through reclustering, we identified eight distinct clusters of urothelial cells. There was a significant reduction in UPK3A+ umbrella cells and a simultaneous increase in progenitor-like pluripotent cells (PPCs) within the HIC bladder. Pseudotime analysis of the urothelial cells in the HIC bladder revealed that cells faced challenges in differentiating into UPK3A+ umbrella cells, while PPCs exhibited substantial proliferation to compensate for the loss of UPK3A+ umbrella cells. The urothelium in HIC remains unrepaired, despite the substantial proliferation of PPCs. Thus, we propose that inhibiting the pivotal signaling pathways responsible for the injury to UPK3A+ umbrella cells is paramount for restoring the urothelial barrier and alleviating lower urinary tract symptoms in HIC patients. Subsequently, we identified key molecular pathways (TLR3 and NR2F6) associated with the injury of UPK3A+ umbrella cells in HIC urothelium. Finally, we conducted in vitro and in vivo experiments to confirm the potential of the TLR3-NR2F6 axis as a promising therapeutic target for HIC. These findings hold the potential to inhibit urothelial injury, providing promising clues for early diagnosis and functional bladder self-repair strategies for HIC patients. © 2024 The Pathological Society of Great Britain and Ireland.

Characteristics of bone metabolism in the male patients with diabetic neuropathy.

BACKGROUND: This study aimed to evaluate the characteristics of bone metabolism and fracture risk in the type 2 diabetes mellitus (T2DM) patients with distal symmetric polyneuropathy (DSPN). METHODS: A total of 198 T2DM individuals were recruited from January 2017 to December 2020. Patients with DSPN were evaluated by strict clinical and sensory thresholds. Biochemical parameters and bone mineral density (BMD) were measured. The BMD, bone turnover markers, and probability of fracture were compared between two groups, and the factors related to BMD and probability of hip fracture in 10 years were further explored. RESULTS: Compared with type 2 diabetes mellitus without distal symmetric polyneuropathy (T2DN-) patients, type 2 diabetes mellitus with distal symmetric polyneuropathy (T2DN+) patients had lower level of cross-linked C-telopeptide (CTX) (0.32 ± 0.19 vs 0.38 ± 0.21 ng/mL, p = 0.038) and higher level of bone-specific alkaline phosphatase (BALP) (15.28 ± 5.56 vs 12.58 ± 4.41 µg/mL, p = 0.003). T2DN+ patients had higher BMD of lumbar L1-L4 (1.05 ± 0.19 vs 0.95 ± 0.37, p = 0.027) and higher probability of hip fracture (0.98 ± 0.88 vs 0.68 ± 0.63, p = 0.009) as compared to T2DN- individuals. Univariate correlation analysis showed that BALP level (coefficient (coef) = -0.054, p = 0.038), CTX level (coef = -2.28, p = 0.001), and hip fracture risk (coef = -1.02, p < 0.001) were negatively related to the BMD of L1-L4. As for the risk of hip fracture evaluated by WHO Fracture Risk Assessment Tool (FRAX), age (coef = 0.035, p < 0.001), use of insulin (coef = 0.31, p =0.015), and levels of BALP (coef = 0.031, p = 0.017) and CTX (coef = 0.7, p = 0.047) were positively related to the risk of hip fracture. Multivariate regression analysis showed that CTX level (coef = -1.41, p = 0.043) was still negatively related to BMD at the lumbar spine. CONCLUSION: This study indicates that T2DM patients with DSPN have special bone metabolism represented by higher BALP level and lower CTX level which may increase BMD at the lumbar spine.