Autophagy in Osteoarthritis: A Double-Edged Sword in Cartilage Aging and Mechanical Stress Response: A Systematic Review.

Background: Although osteoarthritis (OA) development is epidemiologically multifactorial, a primary underlying mechanism is still under debate. Understanding the pathophysiology of OA remains challenging. Recently, experts have focused on autophagy as a contributor to OA development. Method: To better understand the pathogenesis of OA, we survey the literature on the role of autophagy and the molecular mechanisms of OA development. To identify relevant studies, we used controlled vocabulary and free text keywords to search the MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, Web of Science, and SCOPUS database. Thirty-one studies were included for data extraction and systematic review. Among these studies, twenty-five studies investigated the effects of autophagy in aging and OA chondrocytes, six studies examined the effects of autophagy in normal human chondrocytes, and only one study investigated the effects of mechanical stress-induced autophagy on the development of OA in normal chondrocytes. Results: The studies suggest that autophagy activation prevents OA by exerting cell-protective effects in normal human chondrocytes. However, in aging and osteoarthritis (OA) chondrocytes, the role of autophagy is intricate, as certain studies indicate that stimulating autophagy in these cells can have a cytotoxic effect, while others propose that it may have a protective (cytoprotective) effect against damage or degeneration. Conclusions: Mechanical stress-induced autophagy is also thought to be involved in the development of OA, but further research is required to identify the precise mechanism. Thus, autophagy contributions should be interpreted with caution in aging and the types of OA cartilage.

Management of Patients with Ischemic Heart Disease in Spine Surgery.

In ischemic heart disease (IHD), the myocardium does not receive enough blood and oxygen. Although the IHD-related mortality rate is decreasing, the risk remains and is a major predictor of cardiac complications following noncardiac surgery. Given the increase in the older population, the number of patients with spinal diseases requiring surgery is increasing. Among these patients, those with underlying IHD or a high risk of cardiac complications before and after surgery are also increasing. Given that cardiac complications following spinal surgery are associated with delayed patient recovery and even death, spinal surgeons should be knowledgeable about overall patient management, including medication therapy in those at high risk of developing perioperative cardiac complications for successful patient care. Before surgery, the underlying medical conditions of patients should be evaluated. Patients with a history of myocardial infarction should be checked for a history of surgical treatments, and the anticoagulant dose should be controlled depending on the surgery type. In addition, the functional status of patients must be examined before surgery. Functional status can be assessed according to the metabolic equivalent of task (MET). More preoperative cardiac examinations are needed for patients who are unable to perform four METs in daily because of the high risk of postoperative cardiac complications. Patients with a history of IHD require appropriate preoperative management and further postoperative evaluation. When considering surgery, spinal surgeons should be knowledgeable about patient care before and after surgery.

AI-Driven Segmentation and Automated Analysis of the Whole Sagittal Spine from X-ray Images for Spinopelvic Parameter Evaluation.

Spinal-pelvic parameters are utilized in orthopedics for assessing patients' curvature and body alignment in diagnosing, treating, and planning surgeries for spinal and pelvic disorders. Segmenting and autodetecting the whole spine from lateral radiographs is challenging. Recent efforts have employed deep learning techniques to automate the segmentation and analysis of whole-spine lateral radiographs. This study aims to develop an artificial intelligence (AI)-based deep learning approach for the automated segmentation, alignment, and measurement of spinal-pelvic parameters through whole-spine lateral radiographs. We conducted the study on 932 annotated images from various spinal pathologies. Using a deep learning (DL) model, anatomical landmarks of the cervical, thoracic, lumbar vertebrae, sacrum, and femoral head were automatically distinguished. The algorithm was designed to measure 13 radiographic alignment and spinal-pelvic parameters from the whole-spine lateral radiographs. Training data comprised 748 digital radiographic (DR) X-ray images, while 90 X-ray images were used for validation. Another set of 90 X-ray images served as the test set. Inter-rater reliability between orthopedic spine specialists, orthopedic residents, and the DL model was evaluated using the intraclass correlation coefficient (ICC). The segmentation accuracy for anatomical landmarks was within an acceptable range (median error: 1.7-4.1 mm). The inter-rater reliability between the proposed DL model and individual experts was fair to good for measurements of spinal curvature characteristics (all ICC values > 0.62). The developed DL model in this study demonstrated good levels of inter-rater reliability for predicting anatomical landmark positions and measuring radiographic alignment and spinal-pelvic parameters. Automated segmentation and analysis of whole-spine lateral radiographs using deep learning offers a promising tool to enhance accuracy and efficiency in orthopedic diagnostics and treatments.

Mutations of TP53 and genes related to homologous recombination repair in breast cancer with germline BRCA1/2 mutations.

BACKGROUND: Germline mutations of breast cancer susceptibility gene BRCA1 and BRCA2 (gBRCA1/2) are associated with elevated risk of breast cancer in young women in Asia. BRCA1 and BRCA2 proteins contribute to genomic stability through homologous recombination (HR)-mediated double-strand DNA break repair in cooperation with other HR-related proteins. In this study, we analyzed the targeted sequencing data of Korean breast cancer patients with gBRCA1/2 mutations to investigate the alterations in HR-related genes and their clinical implications. MATERIALS AND METHODS: Data of the breast cancer patients with pathogenic gBRCA1/2 mutations and qualified targeted next-generation sequencing, SNUH FiRST cancer panel, were analyzed. Single nucleotide polymorphisms, small insertions, and deletions were analyzed with functional annotations using ANNOVAR. HR-related genes were defined as ABL1, ATM, ATR, BARD1, BRCA1, BRCA2, CDKN1A, CDKN2A, CHEK1, CHEK2, FANCA, FANCD2, FANCG, FANCI, FANCL, KDR, MUTYH, PALB2, POLE, POLQ, RAD50, RAD51, RAD51D, RAD54L, and TP53. Mismatch-repair genes were MLH1, MSH2, and MSH6. Clinical data were analyzed with cox proportional hazard models and survival analyses. RESULTS: Fifty-five Korean breast cancer patients with known gBRCA1/2 mutations and qualified targeted NGS data were analyzed. Ethnically distinct mutations in gBRCA1/2 genes were noted, with higher frequencies of Val1833Ser (14.8%), Glu1210Arg (11.1%), and Tyr130Ter (11.1%) in gBRCA1 and Arg2494Ter (25.0%) and Lys467Ter (14.3%) in gBRCA2. Considering subtypes, gBRCA1 mutations were associated with triple-negative breast cancers (TNBC), while gBRCA2 mutations were more likely hormone receptor-positive breast cancers. At least one missense mutation of HR-related genes was observed in 44 cases (80.0%). The most frequently co-mutated gene was TP53 (38.1%). In patients with gBRCA1/2 mutations, however, genetic variations of TP53 occurred in locations different from the known hotspots of those with sporadic breast cancers. The patients with both gBRCA1/2 and TP53 mutations were more likely to have TNBC, high Ki-67 values, and increased genetic mutations, especially of HR-related genes. Survival benefit was observed in the TP53 mutants of patients with gBRCA2 mutations, compared to those with TP53 wild types. CONCLUSION: Our study showed genetic heterogeneity of breast cancer patients with gBRCA1 and gBRCA2 mutations in the Korean populations. Further studies on precision medicine are needed for tailored treatments of patients with genetic diversity among different ethnic groups.

Imaging of Indocyanine Green-Human Serum Albumin (ICG-HSA) Complex in Secreted Protein Acidic and Rich in Cysteine (SPARC)-Expressing Glioblastoma.

Glioblastoma is the most common and fatal primary glioma and has a severe prognosis. It is a challenge for neurosurgeons to remove brain tumor tissues completely by resection. Meanwhile, fluorescence-guided surgery (FGS) is a technique used in glioma surgery to enhance the visualization of tumor edges to clarify the extent of tumor resection. Indocyanine green (ICG) is the only FDA-approved NIR fluorescent agent. It non-covalently binds to human serum albumin (HSA). Secreted protein acidic and rich in cysteine (SPARC) is an extracellular glycoprotein expressed in gliomas and binds to albumin, suggesting that it plays an important role in tumor uptake of the ICG-HSA complex. Here we demonstrate the binding properties of HSA or SPARC to ICG using surface plasmon resonance and saturation binding assay. According to in vitro and in vivo studies, the results showed that the uptake of ICG-HSA complex was higher in SPARC-expressing glioblastoma cell line and tumor region compared with the uptake of free ICG. Here, we visualized the SPARC-dependent uptake of ICG and ICG-HSA complex in U87MG. Our results demonstrated that the ICG-HSA complex is likely to be used as an efficient imaging agent targeting SPARC-expressing tumors, especially glioblastoma.

Radiation Response Prediction Model Based on Integrated Clinical and Genomic Data Analysis.

PURPOSE: The value of the genomic profiling by targeted gene-sequencing on radiation therapy response prediction was evaluated through integrated analysis including clinical information. Radiation response prediction model was constructed based on the analyzed findings. MATERIALS AND METHODS: Patients who had the tumor sequenced using institutional cancer panel after informed consent and received radiotherapy for the measurable disease served as the target cohort. Patients with irradiated tumor locally controlled for more than 6 months after radiotherapy were defined as the durable local control (DLC) group, otherwise, non-durable local control (NDLC) group. Significant genomic factors and domain knowledge were used to develop the Bayesian Network model to predict radiotherapy response. RESULTS: Altogether, 88 patients were collected for analysis. Of those, 41 (43.6%) and 47 (54.4%) patients were classified as the NDLC and DLC group, respectively. Somatic mutations of NOTCH2 and BCL were enriched in the NDLC group, whereas, mutations of CHEK2, MSH2, and NOTCH1 were more frequently found in the DLC group. Altered DNA repair pathway was associated with better local failure-free survival (hazard ratio, 0.40; 95% confidence interval, 0.19 to 0.86; p=0.014). Smoking somatic signature was found more frequently in the DLC group. Area under the receiver operating characteristic curve of the Bayesian network model predicting probability of 6-month local control was 0.83. CONCLUSION: Durable radiation response was associated with alterations of DNA repair pathway and smoking somatic signature. Bayesian network model could provide helpful insights for high precision radiotherapy. However, these findings should be verified in prospective cohort for further individualization.

Cortical Trajectory Screw Fixation in Lumbar Spine Surgery: A Review of the Existing Literature.

Posterior lumbar fusion is a safe and effective surgical method for diseases, such as lumbar stenosis, spondylolisthesis, lumbar instability, spinal deformity, and tumor. Pedicle screw (PS) fixation was first introduced by Bouche and has been adopted as the gold standard for posterior lumbar fusion. Santoni and colleagues introduced a new methodological screw insertion technique that uses a cortical bone trajectory (CBT), described as that from a medial to lateral path in the transverse axial plane and caudal to the cephalad path in the sagittal plane through the pedicle for maximum contact of the screw with the cortical bone. Owing to the lower invasiveness, superior cortical bone contact, and reduced neurovascular injury incidence, the CBT technique has been widely used in posterior lumbar fusion; however, these advantages have not been proven in clinical/radiological and biomechanical studies. We designed the present study to review the existing evidence and evaluate the merit of CBT screw fixation. Six electronic databases were searched for relevant articles published in August 2020 using the search terms "cortical bone trajectory," "CBT spine," "CBT fixation," "cortical pedicle screws," and "cortical screws." Studies were analyzed and divided into the following groups: "biomechanics investigation," "surgical technique," and "clinical/radiological studies." Most studies compared CBT and PS fixation, and the CBT screw fixation method showed better or similar outcomes.

Can the cortical bone trajectory screw technique be an alternative method to the pedicle screw in posterior lumbar fusion? A systematic review and metaanalysis.

OBJECTIVE: The aim of this study was to verify the practicability of the cortical bone trajectory (CBT) method by comparing the clinical outcomes including the complications between the CBT method and pedicle screws (PSs). METHODS: MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), web of Science, and SCOPUS electronic databases were searched for relevant articles published through March 2021 that compared the outcomes of the CBT and PSs. The data search, extraction, analysis, and quality assessment were performed according to the Cochrane Collaboration guidelines. The clinical and radiological outcomes of both techniques were evaluated using various outcome measures. RESULTS: Sixteen studies with a total of 1173 patients were included in the study. The outcomes in the meta-analysis indicated that the use of CBT fixation showed better results for overall complications (P < 0.0001), symptomatic adjacent segment disease (sASD) (P = 0.007), superior facet joint violation (SFJV) rate (P = 0.007), operating time (P = 0.007), intraoperative blood loss (P < 0.00001), incision length (P = 0.002), length of hospital stay (P = 0.0006), and revision rates (P = 0.02). However, there were no statistically significant differences in fusion rates or detailed complications including hardware complications, wound infections (all P > 0.05) between the CBT method and PS fixation groups. CONCLUSIONS: The present study revealed that the CBT method was associated with higher functional recovery, lower surgical morbidity rates, lower revision rates, and lower overall complication rates including sASD and SFJV rates. However, both the CBT method and PSs had similar fusion rates, complications including hardware complications (screw malposition, screw loosening, and screw pullout) and wound infections. Thus, the CBT method did not outperform the PSs in all aspects. Therefore, it is recommended to select a surgical method in consideration of the patient's bone mineral density, the condition of the pars interarticularis, or the skill level of the surgeon. Prognostic evaluation through long-term follow-up is required, and more high-quality randomized controlled trials are required to verify and strengthen our results. LEVEL OF EVIDENCE: Level III, Therapeutic Study.

Comparative analysis of the association between various serum vitamin D biomarkers and sarcopenia.

BACKGROUND: Vitamin D status is associated with muscle strength and maintenance of muscle fibers. However, which serum vitamin D biomarker better reflects sarcopenia remains unclear. The aim of this study was to investigate associations between various serum vitamin D biomarkers (total 25-hydroxy vitamin D [25(OH)D], bioavailable 25(OH)D, 24,25-dihydroxyvitamin D [24,25(OH)2 D], and vitamin D metabolite ratio [VMR]) and sarcopenia. METHODS: The data for 83 hip fracture patients were finally included in the analysis. Sarcopenia was defined according to the Asia Working Group for Sarcopenia (AWGS) criteria. Measurements of 24,25(OH)2 D and 25(OH)D were made using solid-phase extraction (SPE) and subsequent liquid chromatography-tandem mass spectrometry (LC-MS/MS). Vitamin D binding protein (VDBP) concentration was measured using an enzyme-linked immunosorbent assay. The VMR was calculated by dividing serum 24,25(OH)2 D by serum 25(OH)D and then multiplying by 100. Based on total 25(OH)D, VDBP, and albumin concentrations, bioavailable 25(OH)D concentrations were calculated using the equations from the other previous studies. RESULTS: Bioavailable 25(OH)D levels were significantly (p = 0.030) decreased in the sarcopenia group compared with the non-sarcopenia group. Results of ROC analysis for the diagnosis of sarcopenia using serum level of bioavailable of 25(OH)D revealed that the cutoff point for bioavailable 25(OH)D was 1.70 ng/ml (AUC = 0.649, p < 0.001). In the group with a bioavailable 25(OH)D less than 1.70 ng/ml, the incidence of sarcopenia increased by 3.3 times (odds ratio: 3.33, p = 0.013). CONCLUSION: We demonstrated that bioavailable 25(OH)D was associated with sarcopenia among the various serum vitamin D biomarkers. Bioavailable vitamin D might be helpful for assessing the risk of sarcopenia.

Femoral neck stress fractures after trampoline exercise: A case report.

BACKGROUND: Femoral neck stress fractures (FNSFs) are commonly found in long-distance running athletes. For FNSFs, early diagnosis and proper treatment are important. The objective of this study was to report FNSFs that occurred after excessive exercise using trampoline in middle-aged women. CASE SUMMARY: The patient was a 43-year-old woman who exercised jumping on a trampoline for 6 wk for 1-3 h a day to diet. Exercise includes repeated flexion-extension of the hip joint. The patient was admitted to the hospital due to sudden bilateral groin pain that occurred suddenly during a trampoline exercise. Hip magnetic resonance imaging (MRI) revealed bilateral FNSFs. After 2 wk of follow-up with conservative treatment, the pain slightly decreased. However, it did not disappear completely. It was determined that it was difficult to control symptoms only by conservation treatment. Thus, closed reduction and internal fixation using a cannulated screw were performed for the more painful left hip joint. After operation, the pain was improved. Walking using crutches was possible. Follow-up MRI showed that the right femoral head signal was decreased compared to the left femoral head signal. Therefore, nonsteroidal anti-inflammatory drug and conservative treatment were provided. CONCLUSION: In middle-aged people, excessive trampoline exercise can repeat hip flexion and extension for a short period of time, leading to FNSFs.

Comparison of anterior-only versus combined anterior and posterior fusion for unstable subaxial cervical injuries: a meta-analysis of biomechanical and clinical studies.

OBJECTIVE: The purpose of the present study was to perform a meta-analysis comparing biomechanical and clinical outcomes between anterior-only and combined anterior and posterior fusions to determine which method of cervical fusion yielded better results for unstable cervical injuries. METHODS: The MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Web of Science and SCOPUS electronic databases were searched for relevant articles published through 2000-2019 that compared the biomechanical and clinical outcomes of anterior-only and combined anterior and posterior fusion for unstable cervical fracture. RESULTS: Eight biomechanical and four clinical studies were included in the analysis. There were significant biomechanical differences between the groups with respect to flexion-extension, axial rotation and lateral bending. Combined fusion provided better biomechanical stability for unstable cervical injuries than anterior-only fusion, regardless of the number of corpectomies or the presence of a posterior column injury. However, despite significant biomechanical differences, there were no significant differences in clinical outcomes, such as the degree of neurologic improvement and complications between the two groups. CONCLUSION: Anterior-only and combined anterior and posterior fusions for unstable subaxial cervical injuries can both restore cervical stability. Although combined fusion might have some advantages in terms of stability biomechanically, there were no significant differences in clinical outcomes, such as the degree of neurologic improvement and perioperative complications. Therefore, rather than the routine use of combined fusion for unstable cervical injuries, the selective use of anterior-only or combined fusion according to the type of injury is recommended.

Efficacy and Safety of Human Serum Albumin-Cisplatin Complex in U87MG Xenograft Mouse Models.

Cisplatin (cis-diamminedichloroplatinum (II), CDDP) is a chemotherapeutic drug widely used against many solid tumors. A pharmacokinetics study found that CDDP can bind to human serum albumin (HSA), which is the most abundant plasma protein in serum. HSA has the advantage of being a nanocarrier and can accumulate in tumors by passive targeting and active targeting mediated by the secreted protein acidic and rich in cysteine (SPARC). In this study, we investigated the possibility of using a CDDP-HSA complex (HSA-CDDP) as a SPARC-mediated therapeutic agent. To investigate the HSA-dependent therapeutic effect of HSA-CDDP, we used two types of U87MG glioma cells that express SPARC differently. HSA-CDDP was highly taken up in SPARC expressing cells and this uptake was enhanced with exogenous SPARC treatment in cells with low expression of SPARC. The cytotoxicity of HSA-CDDP was also higher in SPARC-expressing cells. In the tumor model, HSA-CDDP showed a similar tumor growth and survival rate to CDDP only in SPARC-expressing tumor models. The biosafety test indicated that HSA-CDDP was less nephrotoxic than CDDP, based on blood markers and histopathology examination. Our findings show that HSA-CDDP has the potential to be a novel therapeutic agent for SPARC-expressing tumors, enhancing the tumor targeting effect by HSA and reducing the nephrotoxicity of CDDP.

Langerhans cell histiocytosis in the adult clavicle: A case report.

INTRODUCTION: Langerhans` Cell Histiocytosis (LCH) is a rare disease involving proliferation of Langerhans-type cells, which shares immunophenotypic and ultrastructural similarities. In this article, we report a case of Langerhans cell histiocytosis in solitary involvement of clavicle of adult male. PRESENTATION OF CASE: A 21-year-old male visited outpatient department on account of solitary palpable tumorous lesion in right clavicle. The lesion was found 2 weeks before the visit, and it triggered pain but no tenderness. Findings on X-ray, and CT were suggestive of homogeneous osteolytic lesion of the clavicle, and hot uptake was found in right clavicle on bone scan which is commensurate with site of the lesion. Based on findings on MRI, Ewing's sarcoma, osteomyelitis and malignant hematologic malignancies were initially suspected for differential diagnosis. For the purpose of excision and histologic analysis, excisional biopsy was performed. Biopsy concluded with diagnosis of LCH. DISCUSSION: LCH is widely renowned for its frequent occurrence in pediatric ages, and it occurs usually between ages of one and four. It occasionally occurs in adults. LCH in skeletal system usually involves cranium, vertebrae, rib and so forth. It is very rare for LCH to occur exclusively in clavicle when it involves skeletal system. For diagnosis of LCH, sole imaging studies are inadequate, and histologic, immunochemical analyses are confirmative modalities. Treatment of LCH is not currently standardized. CONCLUSIONS: Most of the solitary tumorous lesions in clavicle in adults call for various differential diagnoses. LCH should be considered in the diagnosis of a adult patient with a clavicle mass.

Conjugation of arginylglycylaspartic acid to human serum albumin decreases the tumor-targeting effect of albumin by hindering its secreted protein acidic and rich in cysteine-mediated accumulation in tumors.

Human serum albumin (HSA) accumulates in tumors by the enhanced permeability and retention (EPR) effect, which is a passive targeting effect in tumors. A recent study showed that secreted protein acidic and rich in cysteine (SPARC), an albumin-binding protein, mediates albumin accumulation in tumors. Arg-Gly-Asp (RGD) is a peptide targeting integrin αvß3, which is highly expressed during tumor angiogenesis. We investigated whether conjugation of RGD to HSA could synergistically enhance tumor targeting. Accumulation of cRGDyK-HSA in integrin αvß3-expressing SK-OV3 cells was observed by confocal microscopy. In SK-OV3 cells overexpressing the albumin binding protein SPARC, cellular uptake of HSA increased, but uptake of cRGDyK-HSA did not. cRGDyK-HSA showed decreased tumor accumulation compared with HSA by positron emission tomography (PET) scanning and biodistribution studies in an SK-OV3 xenograft mouse model. In SK-OV3 tumors, HSA accumulation colocalized with SPARC expression, while cRGDyK-HSA only accumulated in the outer region of the tumor, even though SPARC and integrin αvß3 were expressed within the tumor core. We speculate that cRGDyK conjugation to HSA changes the characteristics of HSA and hinders its tumor-targeting effect. Therefore, HSA should be modified to preserve its native characteristics and enhance the tumor-targeting effects of HSA conjugates.

Cytoprotective Effects of Delphinidin for Human Chondrocytes against Oxidative Stress through Activation of Autophagy.

Antioxidant enzymes are decreased in osteoarthritis (OA) patients, implying the role of oxidative stress in osteoarthritis pathogenesis. The aim of this study was to evaluate the cytoprotective effects of delphinidin, a potent antioxidant, in human chondrocytes and the underlying mechanisms. The cytoprotective mechanism induced by delphinidin against oxidative stress (H2O2) in human chondrocytes was investigated. Cell viability and death were evaluated using proapoptotic and antiapoptotic markers such as cleaved caspase-3 (c-caspase-3), cleaved poly(ADP-ribose) polymerase N-acetylcysteine (c-PARP), Bcl-XL, and transcription factors associated with redox and inflammation regulation, including nuclear factor kappa B (NF-κB) and nuclear factor (erythroid-derived 2)-like 2 (Nrf2). Induction of autophagy was assessed by formation of LC3-II and autophagosome-(LC3 punctate, monodansylcadaverine (MDC) and acridine orange staining) in the presence or absence of an autophagy inhibitor. Treatment with delphinidin itself at concentration below 50 µM for 24 h did not affect viability of chondrocytes. Delphinidin inhibited reactive oxygen species (ROS)-induced apoptosis by significantly decreasing apoptosis markers such as c-caspase-3 and c-PARP while increasing antiapoptotic marker Bcl-XL and antioxidant response NF-κB and Nrf2 pathways. Delphinidin also activated cytoprotective autophagy to protect chondrocytes during oxidative stresses. Activation of autophagy with autophagy inducer rapamycin also inhibited ROS-induced cell death and decreased proapoptotic proteins but increased antiapoptotic protein Bcl-XL, NF-κB, and Nrf2. Delphinidin can protect chondrocytes against H2O2-induced apoptosis via activation of Nrf2 and NF-κB and protective autophagy. Thus, it can inhibit OA with protection of chondrocytes. Delphinidin can protect chondrocytes against H2O2-induced ROS with maintenance of homeostasis and redox. These results suggest that delphinidin could be used to protect chondrocytes against age-related oxidative stress and other oxidative stresses in the treatment of OA. Thus, delphinidin may play a critical role in preventing the development and progression of OA.

Secreted protein acidic and rich in cysteine mediates active targeting of human serum albumin in U87MG xenograft mouse models.

Human serum albumin (HSA) is the most abundant plasma protein. The main reason for using HSA as a versatile tool for drug delivery is based on its ability to accumulate in tumors. However, the mechanism of albumin accumulation in tumors is not yet clear. Many researchers using HSA as a drug-carrier have focused on the passive tumor targeting by enhanced permeability and retention (EPR) effect, while other investigators proposed that albumin binding proteins mediate albumin accumulation in tumors. We investigated whether HSA accumulation in tumors is mediated by the EPR effect or by secreted protein acidic and rich in cysteine (SPARC), which is known to be an albumin-binding protein. Methods: To investigate the role of SPARC on HSA accumulation in tumors, we compared HSA uptake in U87MG glioblastoma cells with different SPARC expression. U87MG cells generally express high levels of SPARC and were, therefore, used as SPARC-rich cells. SPARC-less U87MG (U87MG-shSPARC) cells were established by viral-shSPARC transduction. We detected cellular uptake of fluorescence-labeled HSA by confocal microscopy in U87MG and U87MG-shSPARC cells. To demonstrate the mechanism of HSA accumulation in tumors, we injected FNR648-labeled HSA and FITC-labeled dextran in U87MG and U87MG-shSPARC tumor-bearing mice and observed their micro-distribution in tumor tissues. Results: HSA was internalized in cells by binding with SPARC in vitro. HSA accumulation in U87MG glioma was associated with SPARC expression in vivo. FITC-dextran was distributed in U87MG tumors in the vicinity of blood vessels. The distribution of HSA, on the other hand, was observed in the regions remote from blood vessels of U87MG tumor tissues but not in U87MG-shSPARC tumor tissues. Conclusion: Our results demonstrate that the tumor-distribution of HSA is affected not only by the EPR-effect but also by SPARC expression. SPARC enhances HSA accumulation in U87MG glioma and mediates active targeting of HSA in tumors.

Versatile and Finely Tuned Albumin Nanoplatform based on Click Chemistry.

Albumin is one of the most attractive nanoplatforms for targeted imaging and drug delivery due to its biocompatibility and long circulation half-life. However, previously reported albumin-based nanoplatforms have shown inconsistent blood circulation half-life according to the modified methods, and the affecting factors were not well evaluated, which could hamper the clinical translation of albumin-based nanoplatforms. Herein, we developed a finely tuned click-chemistry based albumin nanoplatform (CAN) with a longer circulation half-life and an efficient tumor targeting ability. Methods: CAN was synthesized in two steps. First, albumin was conjugated with ADIBO-NHS (albumin-ADIBO) by reacting albumin with various molar ratios of ADIBO. The number of attached ADIBO moieties was determined using matrix-assisted laser desorption ionization time of flight (MALDI-TOF). Second, the desired modalities including azide-functionalized chelator, a fluorescence dye, and folate were incorporated into albumin-ADIBO using strain-promoted alkyne-azide cycloaddition reaction (SPAAC reaction). The biodistribution and targeting efficiency of functionalized CANs were demonstrated in mice. Results: The degree of functionalization (DOF) and resulting in vivo biodistribution was controlled precisely using the click chemistry approach. Specifically, the numbers of attached azadibenzocyclooctyne (ADIBO) moieties on albumin, the DOF, were optimized by reacting albumin with varying molar ratios of ADIBO with a high reproducibility. Furthermore, we developed a simple and efficient method to estimate the DOF using UV-visible spectrophotometry (UV-vis), which was further validated by matrix-assisted laser desorption ionization time of flight (MALDI-TOF). The biodistribution of CAN could be controlled by DOF, and CAN with an optimized DOF showed a long circulation half-life (> 18 h). CAN was further functionalized using a simple click chemistry reaction with an azide functionalized chelator, a fluorescence dye, and folate. 64Cu- and folate-labeled CAN (64Cu-CAN-FA) showed effective and specific folate receptor targeting in vivo, with an over two-fold higher uptake than the liver at 24 h post-injection. Conclusions: Our development from the precisely controlled DOF demonstrates that an optimized CAN can be used as a multifunctional nanoplatform to obtain a longer half-life with radioisotopes and ligands, and provides an effective method for the development of albumin-based tumor theranostic agents.

Expanding therapeutic utility of carfilzomib for breast cancer therapy by novel albumin-coated nanocrystal formulation.

Carfilzomib (CFZ) is the second-in-class proteasome inhibitor with much improved efficacy and safety profiles over bortezomib in multiple myeloma patients. In expanding the utility of CFZ to solid cancer therapy, the poor aqueous solubility and in vivo instability of CFZ are considered major drawbacks. We investigated whether a nanocrystal (NC) formulation can address these issues and enhance anticancer efficacy of CFZ against breast cancer. The surface of NC was coated with albumin in order to enhance the formulation stability and drug delivery to tumors via interactions with albumin-binding proteins located in and near cancer cells. The novel albumin-coated NC formulation of CFZ (CFZ-alb NC) displayed improved metabolic stability and enhanced cellular interactions, uptake and cytotoxic effects in breast cancer cells in vitro. Consistently, CFZ-alb NC showed greater anticancer efficacy in a murine 4T1 orthotopic breast cancer model than the currently used cyclodextrin-based formulation. Overall, our results demonstrate the potential of CFZ-alb NC as a viable formulation for breast cancer therapy.

Interference-like patterns of static magnetic fields imprinted into polymer/nanoparticle composites.

Interference of waves is important and used in many areas of science and technology but does not extend to static magnetic fields which lack the wave structure. On the other hand, magnetic fields can be spatially modulated using microstructured materials comprising magnetic and non-magnetic domains. Here, we show that when such spatial modulation is coupled to the dynamics of magnetic particles, it can give rise to interference-like patterns. These patterns are imprinted into thin polymer films by overlaying "stamps" presenting periodic arrays of magnetic and nonmagnetic regions. The structures that emerge from such a superposition are sensitive to any motions of the stamps, can depend on the history of these motions, can produce features significantly smaller than those in the stamps, and can be either planar or three-dimensional.

Simultaneous Detection of EGFR and VEGF in Colorectal Cancer using Fluorescence-Raman Endoscopy.

Fluorescence endomicroscopy provides quick access to molecular targets, while Raman spectroscopy allows the detection of multiple molecular targets. Using a simultaneous fluorescence-Raman endoscopic system (FRES), we herein demonstrate its potential in cancer diagnosis in an orthotopically induced colorectal cancer (CRC) xenograft model. In the model, epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF) were targeted with antibody-conjugated fluorescence and surface-enhanced Raman scattering (F-SERS) dots. FRES demonstrated fast signal detection and multiplex targeting ability using fluorescence and Raman signals to detect the F-SERS dots. In addition, FRES showed a multiplex targeting ability even on a subcentimeter-sized CRC after spraying with a dose of 50 µg F-SERS dots. In conclusion, molecular characteristics of tumor cells (EGFR in cancer cell membranes) and tumor microenvironments (VEGF in the extracellular matrix) could be simultaneously investigated when performing a colonoscopy.