More Like this

1. Mediation of Cartilage Matrix Degeneration and Fibrillation by Decorin in Post‐traumatic Osteoarthritis

   https://doi.org/10.1002/art.41254  

   Li, Qing ; Han, Biao ; Wang, Chao ; Tong, Wei ; Wei, Yulong ; Tseng, Wei‐Ju ; Han, Li‐Hsin ; Liu, X. Sherry ; Enomoto‐Iwamoto, Motomi ; Mauck, Robert L. ; et al ( July 2020 , Arthritis & Rheumatology)

   To elucidate the role of decorin, a small leucine‐rich proteoglycan, in the degradation of cartilage matrix during the progression of post‐traumatic osteoarthritis (OA).

   Three‐month–old decorin‐null (Dcn^−/−) and inducible decorin‐knockout (Dcn^iKO) mice were subjected to surgical destabilization of the medial meniscus (DMM) to induce post‐traumaticOA. TheOAphenotype that resulted was evaluated by assessing joint morphology and sulfated glycosaminoglycan (sGAG) staining via histological analysis (n = 6 mice per group), surface collagen fibril nanostructure via scanning electron microscopy (n = 4 mice per group), tissue modulus via atomic force microscopy–nanoindentation (n = 5 or more mice per group) and subchondral bone structure via micro–computed tomography (n = 5 mice per group). Femoral head cartilage explants from wild‐type and Dcn^−/−mice were stimulated with the inflammatory cytokine interleukin‐1β (IL‐1β) in vitro (n = 6 mice per group). The resulting chondrocyte response toIL‐1β and release ofsGAGs were quantified.

   In both Dcn^−/−and Dcn^iKOmice, the absence of decorin resulted in acceleratedsGAGloss and formation of highly aligned collagen fibrils on the cartilage surface relative to the control (P< 0.05). Also, Dcn^−/−mice developed more salient osteophytes, illustrating more severeOA. In cartilage explants treated withIL‐1β, loss of decorin did not alter the expression of either anabolic or catabolic genes. However, a greater proportion ofsGAGs was released to the media from Dcn^−/−mouse explants, in both live and devitalized conditions (P< 0.05).

   In post‐traumaticOA, decorin delays the loss of fragmented aggrecan and fibrillation of cartilage surface, and thus, plays a protective role in ameliorating cartilage degeneration.

    

   more » « less
2. Dynamic Loading and Tendon Healing Affect Multiscale Tendon Properties and ECM Stress Transmission

   https://doi.org/10.1038/s41598-018-29060-y  

   Freedman, Benjamin R. ; Rodriguez, Ashley B. ; Leiphart, Ryan J. ; Newton, Joseph B. ; Ban, Ehsan ; Sarver, Joseph J. ; Mauck, Robert L. ; Shenoy, Vivek B. ; Soslowsky, Louis J. ( July 2018 , Scientific Reports)

   The extracellular matrix (ECM) is the primary biomechanical environment that interacts with tendon cells (tenocytes). Stresses applied via muscle contraction during skeletal movement transfer across structural hierarchies to the tenocyte nucleus in native uninjured tendons. Alterations to ECM structural and mechanical properties due to mechanical loading and tissue healing may affect this multiscale strain transfer and stress transmission through the ECM. This study explores the interface between dynamic loading and tendon healing across multiple length scales using living tendon explants. Results show that macroscale mechanical and structural properties are inferior following high magnitude dynamic loading (fatigue) in uninjured living tendon and that these effects propagate to the microscale. Although similar macroscale mechanical effects of dynamic loading are present in healing tendon compared to uninjured tendon, the microscale properties differed greatly during early healing. Regression analysis identified several variables (collagen and nuclear disorganization, cellularity, and F-actin) that directly predict nuclear deformation under loading. Finite element modeling predicted deficits in ECM stress transmission following fatigue loading and during healing. Together, this work identifies the multiscale response of tendon to dynamic loading and healing, and provides new insight into microenvironmental features that tenocytes may experience following injury and after cell delivery therapies.

    

   more » « less
3. Investigation of multiphasic 3D‐bioplotted scaffolds for site‐specific chondrogenic and osteogenic differentiation of human adipose‐derived stem cells for osteochondral tissue engineering applications

   https://doi.org/10.1002/jbm.b.34542  

   Mellor, Liliana F. ; Nordberg, Rachel C. ; Huebner, Pedro ; Mohiti‐Asli, Mahsa ; Taylor, Michael A. ; Efird, William ; Oxford, Julia T. ; Spang, Jeffrey T. ; Shirwaiker, Rohan A. ; Loboa, Elizabeth G. ( December 2019 , Journal of Biomedical Materials Research Part B: Applied Biomaterials)

   Osteoarthritis is a degenerative joint disease that limits mobility of the affected joint due to the degradation of articular cartilage and subchondral bone. The limited regenerative capacity of cartilage presents significant challenges when attempting to repair or reverse the effects of cartilage degradation. Tissue engineered medical products are a promising alternative to treat osteochondral degeneration due to their potential to integrate into the patient's existing tissue. The goal of this study was to create a scaffold that would induce site‐specific osteogenic and chondrogenic differentiation of human adipose‐derived stem cells (hASC) to generate a full osteochondral implant. Scaffolds were fabricated using 3D‐bioplotting of biodegradable polycraprolactone (PCL) with either β‐tricalcium phosphate (TCP) or decellularized bovine cartilage extracellular matrix (dECM) to drive site‐specific hASC osteogenesis and chondrogenesis, respectively. PCL‐dECM scaffolds demonstrated elevated matrix deposition and organization in scaffolds seeded with hASC as well as a reduction in collagen I gene expression. 3D‐bioplotted PCL scaffolds with 20% TCP demonstrated elevated calcium deposition, endogenous alkaline phosphatase activity, and osteopontin gene expression. Osteochondral scaffolds comprised of hASC‐seeded 3D‐bioplotted PCL‐TCP, electrospun PCL, and 3D‐bioplotted PCL‐dECM phases were evaluated and demonstrated site‐specific osteochondral tissue characteristics. This technique holds great promise as cartilage morbidity is minimized since autologous cartilage harvest is not required, tissue rejection is minimized via use of an abundant and accessible source of autologous stem cells, and biofabrication techniques allow for a precise, customizable methodology to rapidly produce the scaffold.

    

   more » « less
4. Laser micro‐ablation of fibrocartilage tissue: Effects of tissue processing on porosity modification and mechanics

   https://doi.org/10.1002/jbm.b.33997  

   Matuska, A. M. ; McFetridge, P. S. ( September 2017 , Journal of Biomedical Materials Research Part B: Applied Biomaterials)

   The temporomandibular joint disk (TMJd) is an extremely dense and avascular fibrocartilaginous extracellular matrix (ECM) resulting in a limited regenerative capacity. The use of decellularized TMJdas a biocompatible scaffold to guide tissue regeneration is restricted by innate subcellular porosity of the ECM that hinders cellular infiltration and regenerative events. Incorporation of an artificial microporosity through laser micro‐ablation (LMA) can alleviate these cell and diffusion based limitations. In this study, LMA was performed either before or after decellularization to assess to effect of surfactant treatment on porosity modification as well as the resultant mechanical and physical scaffold properties. Under convective flow or agitation schemes, pristine and laser ablated disks were decellularized using either low (0.1% w/v) or high (1% w/v) concentrations of sodium dodecyl sulfate (SDS). Results show that lower concentrations of SDS minimized collagen degradation and tissue swelling while retaining its capacity to solubilize cellular content. Regardless of processing scheme, laser ablated channels incorporated after SDS treatment were relatively smaller and more uniform than those incorporated before SDS treatment, indicating an altered laser interaction with surfactant treated tissues. Smaller channels correlated with less disruption of native biomechanical properties indicating surfactant pre‐treatment is an important consideration when using LMA to produce artificial porosity inex vivoderived tissues. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1858–1868, 2018.

    

   more » « less
5. Detection of early-stage lung cancer with an in vitro panel of activity-based biosensors to measure inflammatory protease enzymes.

   https://doi.org/10.1200/JCO.2022.40.16_suppl.e20551  

   Dempsey, Paul W. ; Aparicio, Cristina-Mihaela Sandu ; Hantula, Spencer ; Covarrubias, Jose ; Varghese, Sunita ; Neri, Raul ; Ehsan, Sumia ; Covarrubias-Zambrano, Obdulia ; Bossmann, Stefan H. ( June 2022 , Journal of Clinical Oncology)

   e20551 Background: Enzyme activity is at the center of all biological processes. When these activities are misregulated by changes in sequence, expression, or activity, pathologies emerge. Misregulation of protease enzymes such as Matrix Metalloproteinases and Cathepsins play a key role in the pathophysiology of cancer. We describe here a novel class of graphene-based, cost effective biosensors that can detect altered protease activation in a blood sample from early stage lung cancer patients. Methods: The Gene Expression Omnibus (GEO) tool was used to identify proteases differentially expressed in lung cancer and matched normal tissue. Biosensors were assembled on a graphene backbone annotated with one of a panel of fluorescently tagged peptides. The graphene quenches fluorescence until the peptide is either cleaved by active proteases or altered by post-translational modification. 19 protease biosensors were evaluated on 431 commercially collected serum samples from non-lung cancer controls (69%) and pathologically confirmed lung cancer cases (31%) tested over two independent cohorts. Serum was incubated with each of the 19 biosensors and enzyme activity was measured indirectly as a continuous variable by a fluorescence plate reader. Analysis was performed using Emerge, a proprietary predictive and classification modeling system based on massively parallel evolving “Turing machine” algorithms. Each analysis stratified allocation into training and testing sets, and reserved an out-of-sample validation set for reporting. Results: 256 clinical samples were initially evaluated including 35% cancer cases evenly distributed across stages I (29%), II (26%), III (24%) and IV (21%). The case controls included common co-morbidies in the at-risk population such as COPD, chronic bronchitis, and benign nodules (19%). Using the Emerge classification analysis, biosensor biomarkers alone (no clinical factors) demonstrated Sensitivity (Se.) = 92% (CI 82%-99%) and Specificity (Sp.) = 82% (CI 69%-91%) in the out-of-sample set. An independent cohort of 175 clinical cases (age 67±8, 52% male) focused on early detection (26% cancer, 70% Stage I, 30% Stage II/III) were similarly evaluated. Classification showed Se. = 100% (CI 79%-100%) and Sp. = 93% (CI 80%-99%) in the out-of-sample set. For the entire dataset of 175 samples, Se. = 100% (CI 92%-100%) and Sp. = 97% (CI 92%-99%) was observed. Conclusions: Lung cancer can be treated if it is diagnosed when still localized. Despite clear data showing screening for lung cancer by Low Dose Computed Tomography (LDCT) is effective, screening compliance remains very low. Protease biosensors provide a cost effective additional specialized tool with high sensitivity and specificity in detection of early stage lung cancer. A large prospective trial of at-risk smokers with follow up is being conducted to evaluate a commercial version of this assay. 

   more » « less