Use of a pH-responsive imatinib mesylate sustained-release hydrogel for the treatment of tendon adhesion by inhibiting PDGFRß/CLDN1 pathway.

Adhesion after tendon injury, which can result in limb movement disorders, is a common clinical complication; however, effective treatment methods are lacking. Hyaluronic acid hydrogels are a new biomedical material used to prevent tendon adhesion owing to their good biocompatibility. In addition, potential drugs that inhibit adhesion formation have gradually been discovered. The anti-adhesion effects of a combination of loaded drugs into hydrogels have become an emerging trend. However, current drug delivery systems usually lack specific regulation of drug release, and the effectiveness of drugs for treating tendon adhesions is mostly flawed. In this study, we identified a new drug, imatinib mesylate (IM), that prevents tendon adhesion and explored its related molecular pathways. In addition, we designed a pH-responsive sustained-release hydrogel for delivery. Using the metal-organic framework ZIF-8 as a drug carrier, we achieved controlled drug release to increase the effective drug dose at the peak of adhesion formation to achieve better therapeutic effects. The results showed that IM blocked the formation of peritendon adhesions by inhibiting the PDGFRß/ERK/STAT3/CLDN1 pathway. Furthermore, the hydrogel with ZIF-8 exhibited better physical properties and drug release curves than the hydrogel loaded only with drugs, showing better prevention and treatment effects on tendon adhesion.

Lymph node metastasis prediction and biological pathway associations underlying DCE-MRI deep learning radiomics in invasive breast cancer.

BACKGROUND: The relationship between the biological pathways related to deep learning radiomics (DLR) and lymph node metastasis (LNM) of breast cancer is still poorly understood. This study explored the value of DLR based on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in LNM of invasive breast cancer. It also analyzed the biological significance of DLR phenotype based on genomics. METHODS: Two cohorts from the Cancer Imaging Archive project were used, one as the training cohort (TCGA-Breast, n = 88) and one as the validation cohort (Breast-MRI-NACT Pilot, n = 57). Radiomics and deep learning features were extracted from preoperative DCE-MRI. After dual selection by principal components analysis (PCA) and relief methods, radiomics and deep learning models for predicting LNM were constructed by the random forest (RF) method. A post-fusion strategy was used to construct the DLR nomograms (DLRNs) for predicting LNM. The performance of the models was evaluated using the receiver operating characteristic (ROC) curve and Delong test. In the training cohort, transcriptome data were downloaded from the UCSC Xena online database, and biological pathways related to the DLR phenotypes were identified. Finally, hub genes were identified to obtain DLR gene expression (RadDeepGene) scores. RESULTS: DLRNs were based on area under curve (AUC) evaluation (training cohort, AUC = 0.98; validation cohort, AUC = 0.87), which were higher than single radiomics models or GoogLeNet models. The Delong test (radiomics model, P = 0.04; GoogLeNet model, P = 0.01) also validated the above results in the training cohorts, but they were not statistically significant in the validation cohort. The GoogLeNet phenotypes were related to multiple classical tumor signaling pathways, characterizing the biological significance of immune response, signal transduction, and cell death. In all, 20 genes related to GoogLeNet phenotypes were identified, and the RadDeepGene score represented a high risk of LNM (odd ratio = 164.00, P < 0.001). CONCLUSIONS: DLRNs combining radiomics and deep learning features of DCE-MRI images improved the preoperative prediction of LNM in breast cancer, and the potential biological characteristics of DLRN were identified through genomics.

Interoceptive regulation of skeletal tissue homeostasis and repair.

Recent studies have determined that the nervous system can sense and respond to signals from skeletal tissue, a process known as skeletal interoception, which is crucial for maintaining bone homeostasis. The hypothalamus, located in the central nervous system (CNS), plays a key role in processing interoceptive signals and regulating bone homeostasis through the autonomic nervous system, neuropeptide release, and neuroendocrine mechanisms. These mechanisms control the differentiation of mesenchymal stem cells into osteoblasts (OBs), the activation of osteoclasts (OCs), and the functional activities of bone cells. Sensory nerves extensively innervate skeletal tissues, facilitating the transmission of interoceptive signals to the CNS. This review provides a comprehensive overview of current research on the generation and coordination of skeletal interoceptive signals by the CNS to maintain bone homeostasis and their potential role in pathological conditions. The findings expand our understanding of intersystem communication in bone biology and may have implications for developing novel therapeutic strategies for bone diseases.

Sustained Release of Dicumarol via Novel Grafted Polymer in Electrospun Nanofiber Membrane for Treatment of Peritendinous Adhesion.

The prevention and treatment of post-traumatic peritendinous adhesion (PA) have always been a great difficulty for orthopedic surgeons. Current treatments include resecting surgery, non-steroidal anti-inflammatory drugs (NSAIDs) usage and implantable membranes, often target single disease pathogenic processes, resulting in unfavorable therapeutic outcomes. Here a polylactic acid (PLA)-dicumarol conjugates-electrospun nanofiber membrane (ENM) (PCD) is generated, which can achieve spatial accuracy and temporal sustainability in drug release. It is further demonstrated that PCD possesses a significantly higher and more sustainable drug release profile than traditional drug-loading ENM. By providing a physical barrier and continuous releasing of dicumarol, PCD implantation significantly reduces tissue adhesion by 25%, decreases fibroblasts activity and inhibits key fibrogenic cytokine transforming growth factor beta (TGFß) production by 30%, and improves the biomechanical tendon property by 14.69%. Mechanistically, PCD potently inhibits the connexin43 (Cx43) and thereby tunes down the fibroblastic TGFß/Smad3 signaling pathway. Thus, this approach leverages the anti-adhesion effect of dicumarol and drug release properties of grafted copolymer ENM by esters to provide a promising therapeutic strategy for patients who suffer from PA.

Feasibility evaluation of intravoxel incoherent motion diffusion-weighted imaging in the diagnosis of skull-base invasion in nasopharyngeal carcinoma.

Objective: This study aimed to evaluate the feasibility of intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) in the diagnosis of skull-base invasion (SBI) in nasopharyngeal carcinoma (NPC). Materials and methods: A total of 50 patients pathologically diagnosed with NPC and a group of 40 controls comprised of those with either normal nasopharynx or patients with nasopharyngitis underwent conventional MRI and IVIM-DWI scans with 3 different groups of b values. Among the 50 patients, 36 patients diagnosed with SBI in NPC were included in the case group according to SBI criteria. All subjects (including those in the control group and case group) were divided into the b1, b2, and b3 groups based on their b values. The pure diffusion coefficient (D), perfusion-related incoherent microcirculation (D*), and microvascular volume fraction (f) values obtained in each measurement area of each group were tested for variance. Next,2 groups of b-value parameters with statistically significant data in the 3 groups were randomly selected for use in both the control group and the case group. A t-test was performed on the D, D*, and f values obtained by measuring each area of the skull base, and the area under the curve (AUC) of the receiver operating characteristic (ROC) was used to evaluate the diagnostic efficacy of the D, D*, and f values. Results: There was no statistical significance among the D, D*, and f values of the b1 and b3 groups (P>0.05), and the differences in parameters between the b1 and b2 groups were statistically significant(P < 0.05),and the differences in parameters between the b3 and b2 groups were also statistically significant(P < 0.05).The f value of the case group, which was obtained using the b1 and b2 parameters in each area of the skull base, was lower than that of the control group (P <0.05).The D, D*, and f values of the case group obtained by the b1 and b2 parameters in the pars petrosa of the temporal bone (including the foramen lacerum) were lower than those of the control group (P<0.05).When the parameters of the b1 group were used in the corpus of sphenoid bone (including the foramen ovale), the D, D*, and f values of the control group and the case group were compared, yielding a statistically significant difference (P<0.05).When the parameters of the b1 group were used, the diagnostic efficacy of the f value in each area of the skull base was the highest (AUC=0.908-0.991), followed by the D* value (AUC=0.624-0.692). Conclusion: When the number of b values <200 s/mm2 in IVIM-DWI accounts for more than half of the selected b values, IVIM-DWI is highly stable for the diagnosis of SBI in NPC. The D, D*, and f values of the bone and muscle areas of the skull base in patients with SBI of NPC showed a downward trend, and the f value had the best diagnostic performance, followed by the D* value, while the D value had the worst. Thus, IVIM-DWI can be used as a noninvasive method in the diagnosis of SBI in NPC.

PDGF-loaded microneedles promote tendon healing through p38/cyclin D1 pathway mediated angiogenesis.

Tendon injury is one of the most serious orthopedic diseases often leading to disability of patients. Major shortages of tendon healing are due to its multiple comorbidities, uncertainty of therapeutic efficacy and insufficient of angiogenesis. With a deeper understanding of angiogenic mechanism of tendon healing, we investigated an innovative microneedle patch loaded with platelet derived growth factor (PDGF) to achieve a constant systemic administration of PDGF to enhance topical tendon healing. Rat achilles tendon injury model was performed as in vivo animal models. Histological staining showed an enhancement of tendon healing quality, especially angiogenesis. Biomechanical studies demonstrated an increase of tendon stiffness, maximum load and maximum stress with treatment of PDGF-loaded microneedles. Furthermore, MAPK/p38/Cyclin D1 pathway and angiogenesis were found to play an important role in tendon healing process by using a biological high throughput RNA-sequence method and bioinformatic analysis. The high throughput RNA-seq tendon healing results were confirmed by histochemical staining and western blot. These results suggest the novel therapeutic potential of PDGF-loaded microneedle patch in tendon surgery.

Self-Healing Hydrogel Embodied with Macrophage-Regulation and Responsive-Gene-Silencing Properties for Synergistic Prevention of Peritendinous Adhesion.

Antiadhesion barriers such as films and hydrogels used to wrap repaired tendons are important for preventing the formation of adhesion tissue after tendon surgery. However, sliding of the tendon can compress the adjacent hydrogel barrier and cause it to rupture, which may then lead to unexpected inflammation. Here, a self-healing and deformable hyaluronic acid (HA) hydrogel is constructed as a peritendinous antiadhesion barrier. Matrix metalloproteinase-2 (MMP-2)-degradable gelatin-methacryloyl (GelMA) microspheres (MSs) encapsulated with Smad3-siRNA nanoparticles are entrapped within the HA hydrogel to inhibit fibroblast proliferation and prevent peritendinous adhesion. GelMA MSs are responsively degraded by upregulation of MMP-2, achieving on-demand release of siRNA nanoparticles. Silencing effect of Smad3-siRNA nanoparticles is around 75% toward targeted gene. Furthermore, the self-healing hydrogel shows relatively attenuated inflammation compared to non-healing hydrogel. The mean adhesion scores of composite barrier group are 1.67 ± 0.51 and 2.17 ± 0.75 by macroscopic and histological evaluation, respectively. The proposed self-healing hydrogel antiadhesion barrier with MMP-2-responsive drug release behavior is highly effective for decreasing inflammation and inhibiting tendon adhesion. Therefore, this research provides a new strategy for the development of safe and effective antiadhesion barriers.

Macrophage Polarization Modulated by NF-κB in Polylactide Membranes-Treated Peritendinous Adhesion.

Foreign body reactions (FBR) to implants seriously impair tissue-implant integration and postoperative adhesion. The macrophage, owing to its phenotypic plasticity, is a major regulator in the formation of the inflammatory microenvironment; NF-κB signaling also plays a vital role in the process. It is hypothesized that NF-κB phosphorylation exerts a proinflammatory regulator in FBR to polylactide membranes (PLA-M) and adhesion. First, in vitro and in vivo experiments show that PLA-M induces NF-κB phosphorylation in macrophages, leading to M1 polarization and release of inflammatory factors. The inflammatory microenvironment formed due to PLA-M accelerates myofibroblast differentiation and release of collagen III and MMP2, jointly resulting in peritendinous adhesion. Therefore, JSH-23 (a selective NF-κB inhibitor)-loaded PLA membrane (JSH-23/PLA-M) is fabricated by blend electrospinning to regulate the associated M1 polarization for peritendinous anti-adhesion. JSH-23/PLA-M specifically inhibits NF-κB phosphorylation in macrophages and exhibits anti-inflammatory and anti-adhesion properties. The findings demonstrate that NF-κB phosphorylation has a critical role in PLA-induced M1 polarization and aggravating FBR to PLA-M. Additionally, JSH-23/PLA-M precisely targets modulation of NF-κB phosphorylation in FBR to break the vicious cycle in peritendinous adhesion therapy.

Identification and Distinction of Tenocytes and Tendon-Derived Stem Cells.

Restoring the normal structure and function of injured tendons is one of the biggest challenges in orthopedics and sports medicine department. The discovery of tendon-derived stem cells (TDSCs) provides a novel perspective to treat tendon injuries, which is expected to be an ideal seed cell to promote tendon repair and regeneration. Because of the lack of specific markers, the identification of tenocytes and TDSCs has not been conclusive in the in vitro study of tendons. In addition, the morphology of tendon derived cells is similar, and the comparison and identification of tenocytes and TDSCs are insufficient, which causes some obstacles to the in vitro study of tendon. In this review, the characteristics of tenocytes and TDSCs are summarized and compared based on some existing research results (mainly in terms of biomarkers), and a potential marker selection for identification is suggested. It is of profound significance to further explore the mechanism of biomarkers in vivo and to find more specific markers.