Jenneke Klein-Nulend - Academia.edu (original) (raw)
Papers by Jenneke Klein-Nulend
Calcified Tissue International, 2007
Physiological Reports
This is an open access article under the terms of the Creative Commons Attribution License, which... more This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Cell Journal (Yakhteh), 2020
Objective This study investigated whether short stimulation (30 minutes) of human adipose stem ce... more Objective This study investigated whether short stimulation (30 minutes) of human adipose stem cells (hASCs) with 1,25-dihydroxyvitamin D3(calcitriol or 1,25-(OH)2VitD3), fitting within the surgical procedure time frame, suffices to induce osteogenic differentiation, and compared this with continuous treatment with 1,25-(OH)2VitD3. Materials and Methods In this experimental study, hASCs were pretreated with/without 10 nM calcitriol for 30 minutes, seeded on biphasic calcium phosphate (BCP), and cultured for 3 weeks with/without 1,25-(OH)2VitD3. Cell attachment was determined 30 minutes after cell seeding. AlamarBlue assay, alkaline phosphatase (ALP) assay, ALP staining, real-time polymerase chain reaction (PCR), and protein assay were used to evaluate the effect of short calcitriol pretreatment on proliferation and osteogenic differentiation of hASCs up to 3 weeks. Results Pretreatment with 1,25-(OH)2VitD3enhanced the attachment of hASCs to BCP by 1.5-fold compared to non- treated c...
Molecules, 2021
Current cell-based bone tissue regeneration strategies cannot cover large bone defects. K-carrage... more Current cell-based bone tissue regeneration strategies cannot cover large bone defects. K-carrageenan is a highly hydrophilic and biocompatible seaweed-derived sulfated polysaccharide, that has been proposed as a promising candidate for tissue engineering applications. Whether κ-carrageenan can be used to enhance bone regeneration is still unclear. In this study, we aimed to investigate whether κ-carrageenan has osteogenic potential by testing its effect on pre-osteoblast proliferation and osteogenic differentiation in vitro. Treatment with κ-carrageenan (0.5 and 2 mg/mL) increased both MC3T3-E1 pre-osteoblast adhesion and spreading at 1 h. K-carrageenan (0.125–2 mg/mL) dose-dependently increased pre-osteoblast proliferation and metabolic activity, with a maximum effect at 2 mg/mL at day three. K-carrageenan (0.5 and 2 mg/mL) increased osteogenic differentiation, as shown by enhanced alkaline phosphatase activity (1.8-fold increase at 2 mg/mL) at day four, and matrix mineralization ...
Journal of Orthopaedic Research, 2017
ABSTRACTWe aimed to develop an in vitro model for bone implant loosening, allowing analysis of bi... more ABSTRACTWe aimed to develop an in vitro model for bone implant loosening, allowing analysis of biophysical and biological parameters contributing to mechanical instability‐induced osteoclast differentiation and peri‐implant bone loss. MLO‐Y4‐osteocytes were mechanically stimulated for 1 h by fluid shear stress using regimes simulating: (i) supraphysiological loading in the peri‐prosthetic interface (2.9 ± 2.9 Pa, 1 Hz, square wave); (ii) physiologic loading in the cortical bone (0.7 ± 0.7 Pa, 5 Hz, sinusoidal wave); and (iii) stress shielding. Cellular morphological parameters, membrane‐bound RANKL expression, gene expression influencing osteoclast differentiation, nitric oxide release and caspase 3/7‐activity were determined. Either Mouse bone marrow cells were cultured on top of loaded osteocytes or osteocyte‐conditioned medium was added to bone marrow cells. Osteoclast differentiation was assessed after 6 days. We found that osteocytes subjected to supraphysiological loading show...
Stem Cells International, 2016
During the initial stages of bone repair, proinflammatory cytokines are released within the injur... more During the initial stages of bone repair, proinflammatory cytokines are released within the injury site, quickly followed by a shift to anti-inflammatory cytokines. The effect of pro- and anti-inflammatory cytokines on osteogenic differentiation of mesenchymal stem cells is controversial. Here, we investigated the effect of the proinflammatory cytokines TNF-α, IL-6, IL-8, and IL-17F and the anti-inflammatory cytokine IL-4 on proliferation and osteogenic differentiation of human adipose stem cells (hASCs). hASCs were treated with TNF-α, IL-6, IL-8, IL-17F, or IL-4 (10 ng/mL) for 72 h mimicking bone repair. TNF-αreduced collagen type I gene expression but increased hASC proliferation and ALP activity. IL-6 also strongly enhanced ALP activity (18-fold), as well as bone nodule formation by hASCs. IL-8 did not affect proliferation or osteogenic gene expression but reduced bone nodule formation. IL-17F decreased hASC proliferation but enhanced ALP activity. IL-4 enhanced osteocalcin gene ...
PLOS ONE, 2015
Polypyrrole (PPy) is a conducting polymer that enables controlled drug release upon electrical st... more Polypyrrole (PPy) is a conducting polymer that enables controlled drug release upon electrical stimulation. We characterized the biocompatibility of PPy with human primary osteoblasts, and the effect of dopants. We investigated the biocompatibility of PPy comprising various dopants, i.e. p-toluene sulfonate (PPy-pTS), chondroitin sulfate (PPy-CS), or dodecylbenzenesulfonate (PPy-DBS), with human primary osteoblasts. PPy-DBS showed the roughest appearance of all surfaces tested, and its wettability was similar to the gold-coated control. The average number of attached cells was 45% higher on PPy-DBS than on PPy-CS or PPy-pTS, although gene expression of the proliferation marker Ki-67 was similar in osteoblasts on all surfaces tested. Osteoblasts seeded on PPy-DBS or gold showed similar vinculin attachment points, vinculin area per cell area, actin filament structure, and Feret's diameter, while cells seeded on PPY-CS or PPY-pTS showed disturbed focal adhesions and were enlarged with disorganized actin filaments. Osteoblasts grown on PPy-DBS or gold showed enhanced alkaline phosphatase activity and osteocalcin gene expression, but reduced osteopontin gene expression compared to cells grown on PPy-pTS and PPy-CS. In conclusion, PPy doped with DBS showed excellent biocompatibility, which resulted in maintaining focal adhesions, cell morphology, cell number, alkaline phosphatase activity, and osteocalcin gene expression. Taken together, conducting polymers doped with DBS are well tolerated by osteoblasts. Our results could provide a basis for the development of novel orthopedic or dental implants with controlled release of antibiotics and pharmaceutics that fight infections or focally enhance bone formation in a tightly controlled manner.
Journal of biomedical materials research. Part B, Applied biomaterials, Oct 26, 2015
Biomimetic coatings to increase endothelialization of blood-contacting materials in biomedical de... more Biomimetic coatings to increase endothelialization of blood-contacting materials in biomedical devices are promising to improve the biocompatibility of these devices. Although a stable extracellular matrix protein coating on a biomaterial's surface is a prerequisite for endothelial cell attachment, it also stimulates platelet adhesion. Therefore, antithrombotic additives, such as nitric oxide donors, to a stable protein coating might lead to successful endothelialization of a material's surface. We aimed to test whether immobilized bioactive nitrite and acidified nitrite-generating sodium nitrite-collagen conjugate on silicone tubes enhances endothelialization by increasing the number of endothelial cells as well as growth hormone production and by decreasing platelet adhesion. Stable collagen immobilization on acrylic acid-grafted silicone tubes decreased the water contact angle from 102° to 56°. Initial 25 µM sodium nitrite in conjugate resulted in maximal growth hormone p...
Journal of gravitational physiology : a journal of the International Society for Gravitational Physiology, 2002
We show the use of a dimensionless parameter alpha h, in properly downscaling a parallel-plate fl... more We show the use of a dimensionless parameter alpha h, in properly downscaling a parallel-plate flow chamber system for flow stimulation of bone cells under microgravity. The proper experimental regime for exposing cells to predictable levels of dynamic fluid shear stress requires: 1) alpha h < 2, based on the consequent quasi-parabolic form of the velocity profile in this regime, and 2) fo m<fc, where the critical frequency fc is the upper threshold for this flow regime, m is the highest harmonic mode of the flow, and fo is the fundamental frequency of fluid flow.
Nederlands tijdschrift voor tandheelkunde, 2002
Low-intensity ultrasound is frequently used for non-invasive diagnostic purposes. However, low in... more Low-intensity ultrasound is frequently used for non-invasive diagnostic purposes. However, low intensity ultrasound can also be used as a therapeutical agent. It has been concluded from animal experiments that it significantly stimulates the growth of bone. In clinical trials an accelerated healing of fracture has been found. Future research has to define the role in dentistry and the final therapeutical value of low intensity ultrasound.
Biomedical materials (Bristol, England), Jan 2, 2015
Surface modification by functional groups promotes endothelialization in biohybrid artificial lun... more Surface modification by functional groups promotes endothelialization in biohybrid artificial lungs, but whether it affects endothelial cell stability under fluid shear stress, and the release of anti-thrombotic factors, e.g. nitric oxide (NO), is unknown. We aimed to test whether surface-modified silicone tubes containing different functional groups, but similar wettability, improve collagen immobilization, endothelialization, cell stability and cell-mediated NO-release. Peroxide, carboxyl, and amine-groups increased collagen immobilization (41-76%). Only amine-groups increased ultimate tensile strength (2-fold). Peroxide and amine enhanced (1.5-2.5 fold), but carboxyl-groups decreased (2.9-fold) endothelial cell number after 6 d. After collagen immobilization, cell numbers were enhanced by all group-modifications (2.8-3.8 fold). Cells were stable under 1 h-fluid shear stress on amine, but not carboxyl or peroxide-group-modified silicone (>50% cell detachment), while cells were ...
Journal of Behavior Therapy and Experimental Psychiatry - J BEHAV THER EXP PSYCHIAT, 2004
Molecular Cancer Research, 2009
Tumor cells in the bone microenvironment are able to initiate a vicious cycle of bone degradation... more Tumor cells in the bone microenvironment are able to initiate a vicious cycle of bone degradation by mobilizing osteoclasts, multinucleated cells specialized in bone degradation. c-Src is highly expressed both in tumors and in osteoclasts. Therefore, drugs like AZD0530, designed to inhibit Src activity, could selectively interfere with both tumor and osteoclast activity. Here we explored the effects of AZD0530 on human osteoclast differentiation and activity. The effect on osteoclasts formed in vivo was assessed in mouse fetal calvarial explants and in isolated rabbit osteoclasts, where it dose-dependently inhibited osteoclast activity. Its effect on formation and activity of human osteoclasts in vitro was determined in cocultures of human osteoblasts and peripheral blood mononuclear cells. AZD0530 was most effective in inhibiting osteoclast-like cell formation when present at the onset of osteoclastogenesis, suggesting that Src activity is important during the initial phase of oste...
Medical & Biological Engineering & Computing, 2008
We investigated whether low-intensity pulsed ultrasound (LIPUS) stimulates chondrocyte proliferat... more We investigated whether low-intensity pulsed ultrasound (LIPUS) stimulates chondrocyte proliferation and matrix production in explants of human articular cartilage obtained from donors suffering from unicompartimental osteoarthritis of the knee, as well as in isolated human chondrocytes in vitro. Chondrocytes and explants were exposed to LIPUS (30 mW/cm 2 ; 20 min/day, 6 days). Stimulation of [ 35 S]-sulphate incorporation into proteoglycans by LIPUS was 1.3-fold higher in degenerative than in collateral monolayers as assessed biochemically and 1.9-fold higher in explants as assessed by autoradiography. LIPUS decreased the number of cell nests containing 1-3 chondrocytes by 1.5 fold in collateral and by 1.6 fold in degenerative explants. LIPUS increased the number of nests containing 4-6 chondrocytes by 4.8 fold in collateral and by 3.9 fold in degenerative explants. This suggests that LIPUS stimulates chondrocyte proliferation and matrix production in chondrocytes of human articular cartilage in vitro. LIPUS might provide a feasible tool for cartilage tissue repair in osteoarthritic patients, since it stimulates chondrocyte proliferation and matrix production. Keywords Low intensity pulsed ultrasound (LIPUS) Á Osteoarthritis Á Articular cartilage Á Chondrocyte proliferation Á Proteoglycans C. M. Korstjens and R. H. H. van der Rijt are first authors.
Journal of Orthopaedic Research, 2004
Several investigations have established a stimulatory effect of low-intensity ultrasound treatmen... more Several investigations have established a stimulatory effect of low-intensity ultrasound treatment on osteogenesis and fracture healing. The objective of this study was to examine whether the stimulatory effect of low-intensity ultrasound results in increased bone cell activity and/or proliferation. Twenty-four paired triplets of metatarsal bone rudiments of twelve 17-days-old fetal mice were dissected and divided into two groups. One group of bone rudiments was treated with pulsating low-intensity ultrasound (30 mW/cm'; 1.5 MHz) for 20 midday for a period of 3 or 6 days. The other group served as controls. After culture, the metatarsal bone rudiments were prepared for computer aided light microscopy. The following histomorphometric parameters were determined: length, width and volume of the calcified cartilage and of the bone collar, and cell number. GLM analysis demonstrated that bone collar volume and calcified cartilage percentage were significantly higher in the ultrasound-stimulated rudiments compared to untreated controls. Further, the calcified cartilage volume bordering the hypertrophic zone was significantly higher than in the center of the bone rudiment. Ultrasound treatment did not change the number of the cells. These results suggest that the stimulatory effect of low-intensity ultrasound on endochondral ossification is likely due to stimulation of bone cell differentiation and calcified matrix production, but not to changed cell proliferation.
Journal of Cellular Physiology, 1996
ABSTRACT
Calcified Tissue International, 2007
Physiological Reports
This is an open access article under the terms of the Creative Commons Attribution License, which... more This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Cell Journal (Yakhteh), 2020
Objective This study investigated whether short stimulation (30 minutes) of human adipose stem ce... more Objective This study investigated whether short stimulation (30 minutes) of human adipose stem cells (hASCs) with 1,25-dihydroxyvitamin D3(calcitriol or 1,25-(OH)2VitD3), fitting within the surgical procedure time frame, suffices to induce osteogenic differentiation, and compared this with continuous treatment with 1,25-(OH)2VitD3. Materials and Methods In this experimental study, hASCs were pretreated with/without 10 nM calcitriol for 30 minutes, seeded on biphasic calcium phosphate (BCP), and cultured for 3 weeks with/without 1,25-(OH)2VitD3. Cell attachment was determined 30 minutes after cell seeding. AlamarBlue assay, alkaline phosphatase (ALP) assay, ALP staining, real-time polymerase chain reaction (PCR), and protein assay were used to evaluate the effect of short calcitriol pretreatment on proliferation and osteogenic differentiation of hASCs up to 3 weeks. Results Pretreatment with 1,25-(OH)2VitD3enhanced the attachment of hASCs to BCP by 1.5-fold compared to non- treated c...
Molecules, 2021
Current cell-based bone tissue regeneration strategies cannot cover large bone defects. K-carrage... more Current cell-based bone tissue regeneration strategies cannot cover large bone defects. K-carrageenan is a highly hydrophilic and biocompatible seaweed-derived sulfated polysaccharide, that has been proposed as a promising candidate for tissue engineering applications. Whether κ-carrageenan can be used to enhance bone regeneration is still unclear. In this study, we aimed to investigate whether κ-carrageenan has osteogenic potential by testing its effect on pre-osteoblast proliferation and osteogenic differentiation in vitro. Treatment with κ-carrageenan (0.5 and 2 mg/mL) increased both MC3T3-E1 pre-osteoblast adhesion and spreading at 1 h. K-carrageenan (0.125–2 mg/mL) dose-dependently increased pre-osteoblast proliferation and metabolic activity, with a maximum effect at 2 mg/mL at day three. K-carrageenan (0.5 and 2 mg/mL) increased osteogenic differentiation, as shown by enhanced alkaline phosphatase activity (1.8-fold increase at 2 mg/mL) at day four, and matrix mineralization ...
Journal of Orthopaedic Research, 2017
ABSTRACTWe aimed to develop an in vitro model for bone implant loosening, allowing analysis of bi... more ABSTRACTWe aimed to develop an in vitro model for bone implant loosening, allowing analysis of biophysical and biological parameters contributing to mechanical instability‐induced osteoclast differentiation and peri‐implant bone loss. MLO‐Y4‐osteocytes were mechanically stimulated for 1 h by fluid shear stress using regimes simulating: (i) supraphysiological loading in the peri‐prosthetic interface (2.9 ± 2.9 Pa, 1 Hz, square wave); (ii) physiologic loading in the cortical bone (0.7 ± 0.7 Pa, 5 Hz, sinusoidal wave); and (iii) stress shielding. Cellular morphological parameters, membrane‐bound RANKL expression, gene expression influencing osteoclast differentiation, nitric oxide release and caspase 3/7‐activity were determined. Either Mouse bone marrow cells were cultured on top of loaded osteocytes or osteocyte‐conditioned medium was added to bone marrow cells. Osteoclast differentiation was assessed after 6 days. We found that osteocytes subjected to supraphysiological loading show...
Stem Cells International, 2016
During the initial stages of bone repair, proinflammatory cytokines are released within the injur... more During the initial stages of bone repair, proinflammatory cytokines are released within the injury site, quickly followed by a shift to anti-inflammatory cytokines. The effect of pro- and anti-inflammatory cytokines on osteogenic differentiation of mesenchymal stem cells is controversial. Here, we investigated the effect of the proinflammatory cytokines TNF-α, IL-6, IL-8, and IL-17F and the anti-inflammatory cytokine IL-4 on proliferation and osteogenic differentiation of human adipose stem cells (hASCs). hASCs were treated with TNF-α, IL-6, IL-8, IL-17F, or IL-4 (10 ng/mL) for 72 h mimicking bone repair. TNF-αreduced collagen type I gene expression but increased hASC proliferation and ALP activity. IL-6 also strongly enhanced ALP activity (18-fold), as well as bone nodule formation by hASCs. IL-8 did not affect proliferation or osteogenic gene expression but reduced bone nodule formation. IL-17F decreased hASC proliferation but enhanced ALP activity. IL-4 enhanced osteocalcin gene ...
PLOS ONE, 2015
Polypyrrole (PPy) is a conducting polymer that enables controlled drug release upon electrical st... more Polypyrrole (PPy) is a conducting polymer that enables controlled drug release upon electrical stimulation. We characterized the biocompatibility of PPy with human primary osteoblasts, and the effect of dopants. We investigated the biocompatibility of PPy comprising various dopants, i.e. p-toluene sulfonate (PPy-pTS), chondroitin sulfate (PPy-CS), or dodecylbenzenesulfonate (PPy-DBS), with human primary osteoblasts. PPy-DBS showed the roughest appearance of all surfaces tested, and its wettability was similar to the gold-coated control. The average number of attached cells was 45% higher on PPy-DBS than on PPy-CS or PPy-pTS, although gene expression of the proliferation marker Ki-67 was similar in osteoblasts on all surfaces tested. Osteoblasts seeded on PPy-DBS or gold showed similar vinculin attachment points, vinculin area per cell area, actin filament structure, and Feret's diameter, while cells seeded on PPY-CS or PPY-pTS showed disturbed focal adhesions and were enlarged with disorganized actin filaments. Osteoblasts grown on PPy-DBS or gold showed enhanced alkaline phosphatase activity and osteocalcin gene expression, but reduced osteopontin gene expression compared to cells grown on PPy-pTS and PPy-CS. In conclusion, PPy doped with DBS showed excellent biocompatibility, which resulted in maintaining focal adhesions, cell morphology, cell number, alkaline phosphatase activity, and osteocalcin gene expression. Taken together, conducting polymers doped with DBS are well tolerated by osteoblasts. Our results could provide a basis for the development of novel orthopedic or dental implants with controlled release of antibiotics and pharmaceutics that fight infections or focally enhance bone formation in a tightly controlled manner.
Journal of biomedical materials research. Part B, Applied biomaterials, Oct 26, 2015
Biomimetic coatings to increase endothelialization of blood-contacting materials in biomedical de... more Biomimetic coatings to increase endothelialization of blood-contacting materials in biomedical devices are promising to improve the biocompatibility of these devices. Although a stable extracellular matrix protein coating on a biomaterial's surface is a prerequisite for endothelial cell attachment, it also stimulates platelet adhesion. Therefore, antithrombotic additives, such as nitric oxide donors, to a stable protein coating might lead to successful endothelialization of a material's surface. We aimed to test whether immobilized bioactive nitrite and acidified nitrite-generating sodium nitrite-collagen conjugate on silicone tubes enhances endothelialization by increasing the number of endothelial cells as well as growth hormone production and by decreasing platelet adhesion. Stable collagen immobilization on acrylic acid-grafted silicone tubes decreased the water contact angle from 102° to 56°. Initial 25 µM sodium nitrite in conjugate resulted in maximal growth hormone p...
Journal of gravitational physiology : a journal of the International Society for Gravitational Physiology, 2002
We show the use of a dimensionless parameter alpha h, in properly downscaling a parallel-plate fl... more We show the use of a dimensionless parameter alpha h, in properly downscaling a parallel-plate flow chamber system for flow stimulation of bone cells under microgravity. The proper experimental regime for exposing cells to predictable levels of dynamic fluid shear stress requires: 1) alpha h < 2, based on the consequent quasi-parabolic form of the velocity profile in this regime, and 2) fo m<fc, where the critical frequency fc is the upper threshold for this flow regime, m is the highest harmonic mode of the flow, and fo is the fundamental frequency of fluid flow.
Nederlands tijdschrift voor tandheelkunde, 2002
Low-intensity ultrasound is frequently used for non-invasive diagnostic purposes. However, low in... more Low-intensity ultrasound is frequently used for non-invasive diagnostic purposes. However, low intensity ultrasound can also be used as a therapeutical agent. It has been concluded from animal experiments that it significantly stimulates the growth of bone. In clinical trials an accelerated healing of fracture has been found. Future research has to define the role in dentistry and the final therapeutical value of low intensity ultrasound.
Biomedical materials (Bristol, England), Jan 2, 2015
Surface modification by functional groups promotes endothelialization in biohybrid artificial lun... more Surface modification by functional groups promotes endothelialization in biohybrid artificial lungs, but whether it affects endothelial cell stability under fluid shear stress, and the release of anti-thrombotic factors, e.g. nitric oxide (NO), is unknown. We aimed to test whether surface-modified silicone tubes containing different functional groups, but similar wettability, improve collagen immobilization, endothelialization, cell stability and cell-mediated NO-release. Peroxide, carboxyl, and amine-groups increased collagen immobilization (41-76%). Only amine-groups increased ultimate tensile strength (2-fold). Peroxide and amine enhanced (1.5-2.5 fold), but carboxyl-groups decreased (2.9-fold) endothelial cell number after 6 d. After collagen immobilization, cell numbers were enhanced by all group-modifications (2.8-3.8 fold). Cells were stable under 1 h-fluid shear stress on amine, but not carboxyl or peroxide-group-modified silicone (>50% cell detachment), while cells were ...
Journal of Behavior Therapy and Experimental Psychiatry - J BEHAV THER EXP PSYCHIAT, 2004
Molecular Cancer Research, 2009
Tumor cells in the bone microenvironment are able to initiate a vicious cycle of bone degradation... more Tumor cells in the bone microenvironment are able to initiate a vicious cycle of bone degradation by mobilizing osteoclasts, multinucleated cells specialized in bone degradation. c-Src is highly expressed both in tumors and in osteoclasts. Therefore, drugs like AZD0530, designed to inhibit Src activity, could selectively interfere with both tumor and osteoclast activity. Here we explored the effects of AZD0530 on human osteoclast differentiation and activity. The effect on osteoclasts formed in vivo was assessed in mouse fetal calvarial explants and in isolated rabbit osteoclasts, where it dose-dependently inhibited osteoclast activity. Its effect on formation and activity of human osteoclasts in vitro was determined in cocultures of human osteoblasts and peripheral blood mononuclear cells. AZD0530 was most effective in inhibiting osteoclast-like cell formation when present at the onset of osteoclastogenesis, suggesting that Src activity is important during the initial phase of oste...
Medical & Biological Engineering & Computing, 2008
We investigated whether low-intensity pulsed ultrasound (LIPUS) stimulates chondrocyte proliferat... more We investigated whether low-intensity pulsed ultrasound (LIPUS) stimulates chondrocyte proliferation and matrix production in explants of human articular cartilage obtained from donors suffering from unicompartimental osteoarthritis of the knee, as well as in isolated human chondrocytes in vitro. Chondrocytes and explants were exposed to LIPUS (30 mW/cm 2 ; 20 min/day, 6 days). Stimulation of [ 35 S]-sulphate incorporation into proteoglycans by LIPUS was 1.3-fold higher in degenerative than in collateral monolayers as assessed biochemically and 1.9-fold higher in explants as assessed by autoradiography. LIPUS decreased the number of cell nests containing 1-3 chondrocytes by 1.5 fold in collateral and by 1.6 fold in degenerative explants. LIPUS increased the number of nests containing 4-6 chondrocytes by 4.8 fold in collateral and by 3.9 fold in degenerative explants. This suggests that LIPUS stimulates chondrocyte proliferation and matrix production in chondrocytes of human articular cartilage in vitro. LIPUS might provide a feasible tool for cartilage tissue repair in osteoarthritic patients, since it stimulates chondrocyte proliferation and matrix production. Keywords Low intensity pulsed ultrasound (LIPUS) Á Osteoarthritis Á Articular cartilage Á Chondrocyte proliferation Á Proteoglycans C. M. Korstjens and R. H. H. van der Rijt are first authors.
Journal of Orthopaedic Research, 2004
Several investigations have established a stimulatory effect of low-intensity ultrasound treatmen... more Several investigations have established a stimulatory effect of low-intensity ultrasound treatment on osteogenesis and fracture healing. The objective of this study was to examine whether the stimulatory effect of low-intensity ultrasound results in increased bone cell activity and/or proliferation. Twenty-four paired triplets of metatarsal bone rudiments of twelve 17-days-old fetal mice were dissected and divided into two groups. One group of bone rudiments was treated with pulsating low-intensity ultrasound (30 mW/cm'; 1.5 MHz) for 20 midday for a period of 3 or 6 days. The other group served as controls. After culture, the metatarsal bone rudiments were prepared for computer aided light microscopy. The following histomorphometric parameters were determined: length, width and volume of the calcified cartilage and of the bone collar, and cell number. GLM analysis demonstrated that bone collar volume and calcified cartilage percentage were significantly higher in the ultrasound-stimulated rudiments compared to untreated controls. Further, the calcified cartilage volume bordering the hypertrophic zone was significantly higher than in the center of the bone rudiment. Ultrasound treatment did not change the number of the cells. These results suggest that the stimulatory effect of low-intensity ultrasound on endochondral ossification is likely due to stimulation of bone cell differentiation and calcified matrix production, but not to changed cell proliferation.
Journal of Cellular Physiology, 1996
ABSTRACT