Effects of hydrostatic pressure, osmotic pressure, and confinement on extracellular matrix associated responses in the nucleus pulposus cells ex vivo.

Spinal movement in both upright and recumbent positions generates changes in physicochemical stresses including hydrostatic pressure (HP), deviatoric stress, and confinement within the intradiscal compartment. The nucleus pulposus (NP) of the intervertebral disc is composed of highly negatively charged extracellular matrix (ECM), which increases osmotic pressure (OP) and generates tissue swelling. In pursuing regenerative therapies for intervertebral disc degeneration, the effects of HP on the cellular responses of NP cells and the ECM environment remain incompletely understood.

Bidirectionally validated and formation of specific depth zone-derived chondrocyte spheroids and clusters.

3D multicellular self-organized cluster models, e.g., organoids are promising tools for developing new therapeutic modalities including gene and cell therapies, pharmacological mechanistic and screening assays.

Cellular behavior and extracellular matrix turnover in bovine annulus fibrosus cells under hydrostatic pressure and deviatoric strain.

Intervertebral disc herniation is a common spinal disorder that is often treated with discectomy when conservative measures fail. To devise therapeutic strategies for tears in the annulus fibrosus (AF), the regenerative capability of AF cells under spinal loading needs to be addressed. We hypothesized that the compressive loading associated with deformation in AF cells reduces synthetic and degradative activities in extracellular matrix and cell proliferation.

Biological Therapeutic Modalities for Intervertebral Disc Diseases: An Orthoregeneration Network (ON) Foundation Review.

Orthoregeneration is defined as a solution for orthopaedic conditions that harnesses the benefits of biology to improve healing, reduce pain, improve function, and, optimally, provide an environment for tissue regeneration. Options include drugs, surgical intervention, scaffolds, biologics as a product of cells, and physical and electromagnetic stimuli. The goal of regenerative medicine is to enhance the healing of tissue after musculoskeletal injuries as both isolated treatment and adjunct to surgical management, using novel therapies to improve recovery and outcomes.

Regenerative Capability of Human Nucleus Pulposus Cells in Degenerated Disc Under Hydrostatic Pressure Mimicking Physiologically Relevant Intradiscal Pressure In Vitro.

Study Design: Isolated human nucleus pulposus (hNP) cells from the degenerated intervertebral disc (IVD) were incubated under hydrostatic pressure (HP) and evaluated for regenerative potential.

Objectives: To characterize metabolic turnover in hNP cells isolated from degenerated IVDs classified by Pfirrmann grade under physiologically relevant HP at high osmolality in vitro.

Summary Of Background Data: We demonstrated that bovine caudal nucleus pulposus cells isolated from healthy cows produced more extracellular matrix under cyclic HP followed by constant pressure (mimicking physiological intradiscal pressure in humans) than under no pressure in vitro.

Repairing Cartilage with Processed Chondrocyte Constructs: A 6-Month Study Using a Porcine Model.

Objective: Autologous chondrocyte implantation was the first cell-based therapy that used a tissue engineering process to repair cartilage defects. Recently improved approaches and tissue-engineered cell constructs have been developed for growing patient populations. We developed a chondrocyte construct using a collagen gel and sponge scaffold and physicochemical stimuli, implanted with a surgical adhesive.

Augmented Chondroitin Sulfate Proteoglycan Has Therapeutic Potential for Intervertebral Disc Degeneration by Stimulating Anabolic Turnover in Bovine Nucleus Pulposus Cells under Changes in Hydrostatic Pressure.

Nucleus pulposus (NP) cells are exposed to changes in hydrostatic pressure (HP) and osmotic pressure within the intervertebral disc. We focused on main disc matrix components, chondroitin sulfate proteoglycan (CSPG) and hyaluronan (HA) to elucidate the capability of augmented CSPG to enhance the anabolism of bovine NP (bNP) cells under repetitive changes in HP at high osmolality. expression with CSPG in the absence of HP was significantly upregulated compared to the no-material control (phosphate buffer saline) under no HP at 3 days, and expression with CSPG under HP was significantly higher than the control with HA under HP at 12 days.

In vitro nucleus pulposus tissue model with physicochemical stresses.

Intervertebral discs (IVDs) are exposed to changes in physicochemical stresses including hydrostatic and osmotic pressure via diurnal spinal motion. Homeostasis, degeneration, and regeneration in IVDs have been studied using in vitro, ex vivo, and animal models. However, incubation of nucleus pulposus (NP) cells in medium has limited capability to reproduce anabolic turnover and regeneration under physicochemical stresses.

Effects of hydrostatic pressure and deviatoric stress on human articular chondrocytes for designing neo-cartilage construct.

Autologous chondrocyte implantation is a promising therapy for the treatment of the articular cartilage defects. Recently, we have developed a three-dimensional chondrocyte construct manufactured with a collagen gel/sponge scaffold and cyclic hydrostatic pressure. However, the roles of various mechanical stresses, specifically hydrostatic pressure and deviatoric stress, as well as poststress loading, were unclear on metabolic function in chondrocytes.

Molecular and histological characteristics of bovine caudal nucleus pulposus by combined changes in hydrostatic and osmotic pressures in vitro.

Intervertebral disc degeneration is ubiquitous among aging patients, and altered matrix homeostasis is one of the key features of this condition. Physicochemical stresses have a significant impact on matrix homeostasis as they lead to progressive degeneration and may be associated with spinal pain and dysfunction. Thus, it is important to understand the cellular and matrix characteristics of nucleus pulposus in response to these stresses, which include hydrostatic and osmotic pressures during alternate loading conditions.

Reproduction of Characteristics of Extracellular Matrices in Specific Longitudinal Depth Zone Cartilage within Spherical Organoids in Response to Changes in Osmotic Pressure.

Articular cartilage is compressed with joint-loading and weight-bearing stresses, followed by a bulging of the tissue during times of off-loading. This loading and off-loading causes changes in water content, and thus alterations in osmotic pressure. Another unique characteristic of articular cartilage is that it has longitudinal depth: surface, middle, and deep zones.

Molecular Mechanisms of Intervertebral Disc Degeneration.

Intervertebral disc degeneration is a well-known cause of disability, the result of which includes neck and back pain with associated mobility limitations. The purpose of this article is to provide an overview of the known molecular mechanisms through which intervertebral disc degeneration occurs as a result of complex interactions of exogenous and endogenous stressors. This review will focus on some of the identified molecular changes leading to the deterioration of the extracellular matrix of both the annulus fibrosus and nucleus pulposus.

Optimization of Extracellular Matrix Synthesis and Accumulation by Human Articular Chondrocytes in 3-Dimensional Construct with Repetitive Hydrostatic Pressure.

Objective The effects of hydrostatic pressure (HP) on the matrix synthesis by human articular chondrocytes have been reported elsewhere. In order to optimize the production of extracellular matrix, we aimed to clarify the effects of repetitive HP on metabolic function by human articular chondrocytes. Design The human articular chondrocytes were expanded and embedded within a collagen gel/sponge scaffold.

Spheroidal Organoids Reproduce Characteristics of Longitudinal Depth Zones in Bovine Articular Cartilage.

Articular cartilage has multiple histologically distinct longitudinal depth zones. Development and pathogenesis occur throughout these zones. Cartilage explants, monolayer cell culture and reconstituted 3-dimensional cell constructs have been used for investigating mechanisms of pathophysiology in articular cartilage.

Methods of high integrity RNA extraction from cell/agarose construct.

Background: Agarose hydrogels are widely used for three-dimensional cell scaffolding in tissue engineering and cell biology. Recently, molecular profiles have been obtained with extraction of a minimal volume of RNA using fluorescent-tagged quantitative polymerase chain reaction (qPCR), which requires high integrity RNA. However, the agarose interferes considerably with the quantity and quality of the extracted RNA.

Hydrostatic pressure-driven three-dimensional cartilage induction using human adipose-derived stem cells and collagen gels.

Background: The chondrogenic potential of adipose-derived stem cells (ASCs) has been previously demonstrated, although several reports have indicated that ASCs produce less cartilage-specific matrix than bone marrow-derived mesenchymal stem cells. In this study, we intended to improve chondrogenic phenotypes of ASCs using hydrostatic pressure (HP), without utilizing any growth factors other than the transforming growth factor-β1.

Methods: Human ASCs (CD13(+), 44(+), 90(+), 14(-), 31(-), 34(-)) were harvested and cultured.

Off-loading of cyclic hydrostatic pressure promotes production of extracellular matrix by chondrocytes.

The addition of cyclic hydrostatic pressure (cHP) to cell culture medium has been used to promote extracellular matrix (ECM) production by articular chondrocytes. Though a combination of cHP followed by atmospheric pressure (AP) has been examined previously, the rationale of such a combination was unclear. We compared the effects of loading once versus twice (combinations of cHP followed by AP) regarding both gene expression and biochemical and histological phenotypes of chondrocytes.

Effects of mouse genotype on bone wound healing and irradiation-induced delay of healing.

We tested the effects of mouse genotype (C57BL/6NHsd, NOD/SCID, SAMR1, and SAMP6) and ionizing irradiation on bone wound healing. Unicortical wounds were made in the proximal tibiae, and the time course of spontaneous healing and effects of irradiation were monitored radiographically and histologically. There was reproducible healing beginning with intramedullary osteogenesis, subsequent bone resorption by osteoclasts, gradual bridging of the cortical wound, and re-population of medullary hematopoietic cells.

Morphological study of the TK cholangiocarcinoma cell line with three-dimensional cell culture.

Cholangiocarcinoma is an intractable carcinoma originating from the bile duct epithelium. To gain an understanding of the cell biology of cholangiocarcinoma, in vitro cell culture is valuable. However, well‑characterized cell lines are limited.

Wnt pathway regulation by demineralized bone is approximated by both BMP-2 and TGF-β1 signaling.

Allogeneic demineralized bone is used extensively as a clinical graft material because it has osteo/chondroinductive and osteoconductive properties. Demineralized bone powder (DBP) induces chondrogenic differentiation of human dermal fibroblasts (hDFs) in three-dimensional collagen cultures, but the initiating mechanisms have not been fully characterized nor has it been shown that bone morphogenetic proteins (BMPs) recapitulate DBP's effects on target cells. Among the many signaling pathways regulated in hDFs by DBP prior to in vitro chondrogenesis, there are changes in Wnts and their receptors that may contribute to DBP actions.

Using changes in hydrostatic and osmotic pressure to manipulate metabolic function in chondrocytes.

Articular cartilage has distinct histological depth zones. In each zone, chondrocytes are subject to different hydrostatic (HP) and osmotic pressure (OP) due to weight-bearing and joint-loading. Previous in vitro studies of regeneration and pathophysiology in cartilage have failed to consider the characteristics of histological heterogeneity and the effects of combinations of changes in HP and OP.

Novel cell culture model using pure hydrostatic pressure and a semipermeable membrane pouch.

Cell constructs and culture methods are essential tools in tissue engineering. The cell construct should be equivalent to the native cartilage it is intended to replace. Thus, three-dimensional cell constructs are usually composed of a high density of cells and dense extracellular matrix.

Three-dimensional cell culture of glioma and morphological comparison of four different human cell lines.

Background: To explore the intracranial behaviors of glioma, a three-dimensional culture was devised and the morphology of four cell lines was examined.

Materials And Methods: Bioabsorbable and degradable gelatin was used as the scaffold and T98G, A172, KNS42, and U118MG representative standard malignant glioma cell lines were cultured three-dimensionally.

Results: When grown, the cells demonstrated characteristic conformations.