Osteochondral Tissue Chip Derived From iPSCs: Modeling OA Pathologies and Testing Drugs

A biphasic micro and nanostructured scaffold with hydroxyapatite and extracellular matrix components was created for the regeneration of osteochondral tissue. Material cues of the biphasic scaffold supported differentiation of bone marrow stromal cells in both osteogenic and chondrogenic lineages.

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Silk Fibroin/Nano-CaP Bilayered Scaffolds for Osteochondral Tissue Engineering

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.587.245 ◽

2013 ◽

Vol 587 ◽

pp. 245-248 ◽

Cited By ~ 19

Author(s):

Le Ping Yan ◽

Joaquim Miguel Oliveira ◽

Ana L. Oliveira ◽

Rui L. Reis

Keyword(s):

Tissue Engineering ◽

Simulated Body Fluid Solution ◽

Single Layer ◽

Bottom Layer ◽

Apatite Crystal ◽

Crystal Formation ◽

Micro Computed Tomography ◽

Computed Tomography Images ◽

Osteochondral Tissue ◽

Osteochondral Tissue Engineering

In this study, bilayered silk and silk/nanoCaP scaffolds were developed for osteochondral tissue engineering. Aqueous silk solution (16 wt.%) was used for preparation of the cartilage-like layer and, for generation of the silk/nanoCaP suspension and the bottom layer (CaP/Silk: 16 wt.%). The scaffolds were formed by using salt-leaching/lyophilization approach. The scanning electron microscopy revealed that the both layers presented porous structure and integrated well. Micro-computed tomography images confirmed that the CaP phase was only retained in the silk/nanoCaP layer. The hydration degree and mechanical properties of the bilayered scaffold were comparable to the ones of each single layer. The apatite crystal formation was limited to the silk/nanoCaP layer, when soaking the scaffold in a simulated body fluid solution, which is a must for the application of the developed scaffolds in OC tissue engineering.

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A randomized and prospective study on the value of antibiotic prophylaxis administration in transurethral resection of the prostate

Sao Paulo Medical Journal ◽

10.1590/s1516-31802004000100002 ◽

2004 ◽

Vol 122 (1) ◽

pp. 4-7 ◽

Cited By ~ 6

Author(s):

Paulo Rodrigues ◽

Flávio Hering ◽

Alex Meller ◽

João Carlos Campagnari ◽

Márcio D'Império

Keyword(s):

Antibiotic Prophylaxis ◽

Transurethral Resection ◽

Bacterial Resistance ◽

Statistical Significance ◽

Tertiary Care ◽

Prostatic Tissue ◽

Significant Difference ◽

Antibiotic Group ◽

Tissue Chip ◽

Bacterial Sensitivity

CONTEXT: Antibiotic prophylaxis in transurethral resection of the prostate is a regular practice in urology. However, its prophylactic effect can be questioned when the antiseptic surgical technique is used. Nonetheless, urine culture-oriented antibiotic therapy is the gold standard for avoiding improper medication usage and bacterial resistance. OBJECTIVE: To study the efficacy of antibiotic usage in patients with negative urine cultures, who were submitted to transurethral resection of the prostate. TYPE OF STUDY: Prospective open labeled study. SETTING: Tertiary care referral hospital PARTICIPANTS: 124 consecutive patients, who were randomly divided into two groups to receive antibiotic prophylaxis or not. MAIN MEASUREMENTS: Cultures from meatus, urine, irrigation and antiseptic fluid, and prostate tissue chips, were compared and analyzed for bacterial sensitivity to the antibiotic used, according to the surgeon's personal criteria. McLennan's test was used for statistical analysis. RESULTS: No statistically significant difference regarding clinical evolution was found between the groups that received or antibiotics or not. Statistical significance was found regarding the occurrence of positive urine cultures during the postoperative period for those not receiving antibiotics, but not in relation to fever, prostate chip culture or bacteremic episodes. Sixty-eight subjects (57.1%) presented positive prostatic tissue culture. There was no specific correlation between the recovered bacteria from the meatus, prostatic tissue chip and urine and the spectrum of the administered antibiotic. Six cases showed the same bacteria in the urine and prostatic tissue chip. Only fifteen cases (25%) in the antibiotic group showed the desired sensitivity directed to the collected bacteria. CONCLUSIONS: Antibiotic prophylaxis for patients whose urine is sterile is debatable in patients who are candidates for transurethral resection of the prostate. Most of the time, the antibiotic agent used is not specific for any of the bacteria recovered from the various sources analyzed.

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NIH Funds “Tissue Chip” Models for Drug Screening

JAMA ◽

10.1001/jama.2017.15522 ◽

2017 ◽

Vol 318 (16) ◽

pp. 1531

Author(s):

Jeff Lyon

Keyword(s):

Drug Screening ◽

Tissue Chip

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Core-shell bioprinting as a strategy to apply differentiation factors in a spatially defined manner inside osteochondral tissue substitutes

Biofabrication ◽

10.1088/1758-5090/ac457b ◽

2021 ◽

Author(s):

David Kilian ◽

Silvia Cometta ◽

Anne Bernhardt ◽

Rania Taymour ◽

Jonas Golde ◽

...

Keyword(s):

Binding Capacity ◽

Close Contact ◽

Release Kinetics ◽

Cell Types ◽

Core Shell ◽

The Core ◽

Differentiation Factors ◽

Local Supply ◽

Osteochondral Tissue ◽

Different Cell Types

Abstract One of the key challenges in osteochondral tissue engineering is to define specified zones with varying material properties, cell types and biochemical factors supporting locally adjusted differentiation into the osteogenic and chondrogenic lineage, respectively. Herein, extrusion-based core-shell bioprinting is introduced as a potent tool allowing a spatially defined delivery of cell types and differentiation factors TGF-β3 and BMP-2 in separated compartments of hydrogel strands, and, therefore, a local supply of matching factors for chondrocytes and osteoblasts. Ink development was based on blends of alginate and methylcellulose, in combination with varying concentrations of the nanoclay Laponite whose high affinity binding capacity for various molecules was exploited. Release kinetics of model molecules was successfully tuned by Laponite addition. Core-shell bioprinting was proven to generate well-oriented compartments within one strand as monitored by optical coherence tomography in a non-invasive manner. Chondrocytes and osteoblasts were applied each in the shell while the respective differentiation factors (TGF-β3, BMP-2) were provided by a Laponite-supported core serving as central factor depot within the strand, allowing directed differentiation of cells in close contact to the core. Experiments with bi-zonal constructs, comprising an osteogenic and a chondrogenic zone, revealed that the local delivery of the factors from the core reduces effects of these factors on the cells in the other scaffold zone. These observations prove the general suitability of the suggested system for co-differentiation of different cell types within a zonal construct.

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Development and analytical validation of a finite element model of fluid transport through osteochondral tissue

10.1101/2020.10.26.356188 ◽

2020 ◽

Author(s):

Brady D. Hislop ◽

Chelsea M. Heveran ◽

Ronald K. June

Keyword(s):

Finite Element ◽

Finite Element Model ◽

Fluid Transport ◽

Fluid Pressure ◽

Viscoelastic Model ◽

Element Model ◽

Pressure Gradients ◽

Superficial Zone ◽

Bone Interface ◽

Osteochondral Tissue

AbstractFluid transport between cartilage and bone is critical to joint health. The objective of this study was to develop and analytically validate a finite element model of osteochondral tissue capable of modeling cartilage-bone fluid transport. A biphasic viscoelastic model using an ellipsoidal fiber distribution was created with three distinct layers of cartilage (superficial zone, middle zone, and deep zone) along with a layer of subchondral bone. For stress-relaxation in unconfined compression, our results for compressive stress, radial stress, effective fluid pressure, and elastic recoil were compared with established biphasic analytical solutions. Our model also shows the development of fluid pressure gradients at the cartilage-bone interface during loading. Fluid pressure gradients developed at the cartilage-bone interface with consistently higher pressures in cartilage following initial loading to 10% strain, followed by convergence towards equal pressures in cartilage and bone during the 400s relaxation period. These results provide additional evidence that fluid is transported between cartilage and bone during loading and improves upon estimates of the magnitude of this effect through incorporating a realistic distribution and estimate of the collagen ultrastructure. Understanding fluid transport between cartilage and bone may be key to new insights about the mechanical and biological environment of both tissues in health and disease.

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