American Journal of Physiology-Heart and Circulatory Physiology, 2000
Basic fibroblast growth factor (FGF-2) may protect the heart from ischemia-reperfusion injury (st... more Basic fibroblast growth factor (FGF-2) may protect the heart from ischemia-reperfusion injury (stunning) by stimulating nitric oxide (NO) production. To test this hypothesis, we pretreated coronary-perfused mouse hearts with 1 μg/ml FGF-2 or vehicle control before the onset of ischemia. Intracellular calcium (Cai2+) was estimated by aequorin, and NO release was measured with an NO-selective electrode. Hearts perfused with FGF-2 maintained significantly better left ventricular (LV) function during ischemia than hearts perfused with vehicle. FGF-2 significantly delayed the onset of ischemic contracture and improved LV recovery during reperfusion. Cai2+was similar in both groups at baseline during ischemia and reperfusion.l- N6-(1-iminoethyl)lysine, a selective inhibitor of inducible NO synthase (NOS2), obliterated the protective effects of FGF-2. In transgenic hearts deficient in the expression of NOS2 (NOS2−/−), FGF-2 did not attenuate ischemia-induced LV dysfunction. Measurements of...
Hepatocyte transplantation partially corrects genetic disorders and has been associated anecdotal... more Hepatocyte transplantation partially corrects genetic disorders and has been associated anecdotally with reversal of acute liver failure. Monitoring for graft function and rejection has been difficult, and has contributed to limited graft survival. Preparative hepatic irradiation was examined in non-human primates as a strategy to improve engraftment of donor hepatocytes, and was then applied in human subjects. T-cell immune monitoring was also examined in human subjects to assess adequacy of immunosuppression. Porcine hepatocyte transplants engrafted and expanded to comprise up to 15% of irradiated segments in immunosuppressed monkeys preconditioned with 10Gy liver-directed irradiation. Two patients with urea cycle deficiencies had early graft loss following hepatocyte transplantation; retrospective immune monitoring suggested the need for additional immunosuppression. Preparative radiation, anti-lymphocyte induction, and frequent immune monitoring were instituted for hepatocyte tr...
La presente invention concerne une methode de traitement d'un patient presentant un trouble i... more La presente invention concerne une methode de traitement d'un patient presentant un trouble inflammatoire, par administration audit patient (i) d'un antidepresseur tricyclique (par exemple, d'amoxapine); et (ii) d'un corticosteroide (par exemple, de prednisolone) simultanement ou a 14 jours d'intervalle en quantites suffisantes pour diminuer ou empecher l'inflammation.
Injuries to the inner regions of the knee meniscus do not heal and can result in degenerative cha... more Injuries to the inner regions of the knee meniscus do not heal and can result in degenerative changes to the articular surface, ultimately leading to osteoarthritis. A possible stimulus to enhance meniscus healing is to use electric fields that induce galvanotaxis. In this study, a novel characterization of the effects of direct current electric fields on migration characteristics of meniscus cells was performed. Primary and passaged inner and outer meniscus cells were exposed to varying electric field strengths from 0 to 6 V/cm. Cell migration was tracked using time lapse digital photography, and cell displacement and cathodal direct velocity were quantified. Cytoskeletal staining was performed to examine actin distribution and nuclear content. Cell adhesion strength was quantified as a function of wall shear stress. Meniscus cells exhibited cathodal migration and cell elongation perpendicular to the applied electric field accompanied by actin reorganization. Outer meniscus cells migrated quicker and exhibited lower adhesion strengths when compared to inner meniscus cells. Passaged cells exhibited higher migration characteristics when compared to primary cells. Overall, this study demonstrated that electric fields can significantly enhance and direct meniscus cell migration and suggests the potential for their incorporation in strategies of meniscus repair and tissue engineering.
Creation of functional skin substitutes within a clinically acceptable time window is essential f... more Creation of functional skin substitutes within a clinically acceptable time window is essential for timely repair and management of large wounds such as extensive burns. The aim of this study was to investigate the possibility of fabricating skin substitutes via a bottom-up nanofiber-enabled cell assembly approach and using such substitutes for full-thickness wound repair in nude mice. Following a layer-by-layer (L-b-L) manner, human primary skin cells (fibroblasts and keratinocytes) were rapidly assembled together with electrospun polycaprolactone (PCL)/collagen (3:1, w/w; 8%, w/v) nanofibers into 3D constructs, in which fibroblasts and keratinocytes were located in the bottom and upper portion respectively. Following culture, the constructs developed into a skin-like structure with expression of basal keratinocyte markers and deposition of new matrix while exhibiting good mechanical strength (as high as 4.0MPa by 14 days). Treatment of the full-thickness wounds created on the back of nude mice with various grafts (acellular nanofiber meshes, dermal substitutes, skin substitutes and autografts) revealed that 14-day-cultured skin substitutes facilitated a rapid wound closure with complete epithelialization comparable to autografts. Taken together, skin-like substitutes can be formed by L-b-L assembling human skin cells and biomimetic nanofibers and they are effective to heal acute full-thickness wounds in nude mice.
ASME 2010 Summer Bioengineering Conference, Parts A and B, 2010
ABSTRACT The clinical potential of stem cells has driven forward efforts toward their optimizatio... more ABSTRACT The clinical potential of stem cells has driven forward efforts toward their optimization for tissue engineering applications. The intimal layer of the synovium is composed of two cell types, macrophages and fibroblast-like cells. The fibroblast-like cells, often referred to as synovial-derived mesenchymal stem cells (sMSCs), have the capability to differentiate down a chondrogenic lineage1. In addition, in vivo tests have shown that synovial cells may be recruited from the synovial membrane to aid in the repair of articular cartilage defects2.
The concept of cartilage functional tissue engineering (FTE) has promoted the use of physiologic ... more The concept of cartilage functional tissue engineering (FTE) has promoted the use of physiologic loading bioreactor systems to cultivate engineered tissues with load-bearing properties. Prior studies have demonstrated that culturing agarose constructs seeded with primary bovine chondrocytes from immature joints, and subjected to dynamic deformation, produced equilibrium compressive properties and proteoglycan content matching the native tissue. In the process of translating these results to an adult canine animal model, it was found that protocols previously successful with immature bovine primary chondrocytes did not produce the same successful outcome when using adult canine primary chondrocytes. The objective of this study was to assess the efficacy of a modified FTE protocol using adult canine chondrocytes seeded in agarose hydrogel and subjected to dynamic loading. Two modes of dynamic loading were applied to constructs using custom bioreactors: unconfined axial compressive deformational loading (DL; 1 Hz, 10% deformation) or sliding contact loading (Slide; 0.5 Hz, 10% deformation). Loading for 3 h daily was initiated on day 0, 14, or 28 (DL0, DL14, DL28, and Slide14). Constructs with applied loading (both DL and Slide) exhibited significant increases in Young's modulus compared with free-swelling control as early as day 28 in culture (p < 0.05). However, glycosaminoglycan, collagen, and DNA content were not statistically different among the various groups. The modulus values attained for engineered constructs compare favorably with (and exceed in some cases) those of native canine knee (patella groove and condyle) cartilage. Our findings successfully demonstrate an FTE strategy incorporating clinically relevant, adult chondrocytes and gel scaffold for engineering cartilage replacement tissue. These results, using continuous growth factor supplementation, are in contrast to our previously reported studies with immature chondrocytes where the sequential application of dynamic loading after transient transforming growth factor-beta3 application was found to be a superior culture protocol. Sliding, which simulates aspects of joint articulation, has shown promise in promoting engineered tissue development and provides an alternative option for FTE of cartilage constructs to be further explored.
American Journal of Physiology-Heart and Circulatory Physiology, 2000
Basic fibroblast growth factor (FGF-2) may protect the heart from ischemia-reperfusion injury (st... more Basic fibroblast growth factor (FGF-2) may protect the heart from ischemia-reperfusion injury (stunning) by stimulating nitric oxide (NO) production. To test this hypothesis, we pretreated coronary-perfused mouse hearts with 1 μg/ml FGF-2 or vehicle control before the onset of ischemia. Intracellular calcium (Cai2+) was estimated by aequorin, and NO release was measured with an NO-selective electrode. Hearts perfused with FGF-2 maintained significantly better left ventricular (LV) function during ischemia than hearts perfused with vehicle. FGF-2 significantly delayed the onset of ischemic contracture and improved LV recovery during reperfusion. Cai2+was similar in both groups at baseline during ischemia and reperfusion.l- N6-(1-iminoethyl)lysine, a selective inhibitor of inducible NO synthase (NOS2), obliterated the protective effects of FGF-2. In transgenic hearts deficient in the expression of NOS2 (NOS2−/−), FGF-2 did not attenuate ischemia-induced LV dysfunction. Measurements of...
Hepatocyte transplantation partially corrects genetic disorders and has been associated anecdotal... more Hepatocyte transplantation partially corrects genetic disorders and has been associated anecdotally with reversal of acute liver failure. Monitoring for graft function and rejection has been difficult, and has contributed to limited graft survival. Preparative hepatic irradiation was examined in non-human primates as a strategy to improve engraftment of donor hepatocytes, and was then applied in human subjects. T-cell immune monitoring was also examined in human subjects to assess adequacy of immunosuppression. Porcine hepatocyte transplants engrafted and expanded to comprise up to 15% of irradiated segments in immunosuppressed monkeys preconditioned with 10Gy liver-directed irradiation. Two patients with urea cycle deficiencies had early graft loss following hepatocyte transplantation; retrospective immune monitoring suggested the need for additional immunosuppression. Preparative radiation, anti-lymphocyte induction, and frequent immune monitoring were instituted for hepatocyte tr...
La presente invention concerne une methode de traitement d'un patient presentant un trouble i... more La presente invention concerne une methode de traitement d'un patient presentant un trouble inflammatoire, par administration audit patient (i) d'un antidepresseur tricyclique (par exemple, d'amoxapine); et (ii) d'un corticosteroide (par exemple, de prednisolone) simultanement ou a 14 jours d'intervalle en quantites suffisantes pour diminuer ou empecher l'inflammation.
Injuries to the inner regions of the knee meniscus do not heal and can result in degenerative cha... more Injuries to the inner regions of the knee meniscus do not heal and can result in degenerative changes to the articular surface, ultimately leading to osteoarthritis. A possible stimulus to enhance meniscus healing is to use electric fields that induce galvanotaxis. In this study, a novel characterization of the effects of direct current electric fields on migration characteristics of meniscus cells was performed. Primary and passaged inner and outer meniscus cells were exposed to varying electric field strengths from 0 to 6 V/cm. Cell migration was tracked using time lapse digital photography, and cell displacement and cathodal direct velocity were quantified. Cytoskeletal staining was performed to examine actin distribution and nuclear content. Cell adhesion strength was quantified as a function of wall shear stress. Meniscus cells exhibited cathodal migration and cell elongation perpendicular to the applied electric field accompanied by actin reorganization. Outer meniscus cells migrated quicker and exhibited lower adhesion strengths when compared to inner meniscus cells. Passaged cells exhibited higher migration characteristics when compared to primary cells. Overall, this study demonstrated that electric fields can significantly enhance and direct meniscus cell migration and suggests the potential for their incorporation in strategies of meniscus repair and tissue engineering.
Creation of functional skin substitutes within a clinically acceptable time window is essential f... more Creation of functional skin substitutes within a clinically acceptable time window is essential for timely repair and management of large wounds such as extensive burns. The aim of this study was to investigate the possibility of fabricating skin substitutes via a bottom-up nanofiber-enabled cell assembly approach and using such substitutes for full-thickness wound repair in nude mice. Following a layer-by-layer (L-b-L) manner, human primary skin cells (fibroblasts and keratinocytes) were rapidly assembled together with electrospun polycaprolactone (PCL)/collagen (3:1, w/w; 8%, w/v) nanofibers into 3D constructs, in which fibroblasts and keratinocytes were located in the bottom and upper portion respectively. Following culture, the constructs developed into a skin-like structure with expression of basal keratinocyte markers and deposition of new matrix while exhibiting good mechanical strength (as high as 4.0MPa by 14 days). Treatment of the full-thickness wounds created on the back of nude mice with various grafts (acellular nanofiber meshes, dermal substitutes, skin substitutes and autografts) revealed that 14-day-cultured skin substitutes facilitated a rapid wound closure with complete epithelialization comparable to autografts. Taken together, skin-like substitutes can be formed by L-b-L assembling human skin cells and biomimetic nanofibers and they are effective to heal acute full-thickness wounds in nude mice.
ASME 2010 Summer Bioengineering Conference, Parts A and B, 2010
ABSTRACT The clinical potential of stem cells has driven forward efforts toward their optimizatio... more ABSTRACT The clinical potential of stem cells has driven forward efforts toward their optimization for tissue engineering applications. The intimal layer of the synovium is composed of two cell types, macrophages and fibroblast-like cells. The fibroblast-like cells, often referred to as synovial-derived mesenchymal stem cells (sMSCs), have the capability to differentiate down a chondrogenic lineage1. In addition, in vivo tests have shown that synovial cells may be recruited from the synovial membrane to aid in the repair of articular cartilage defects2.
The concept of cartilage functional tissue engineering (FTE) has promoted the use of physiologic ... more The concept of cartilage functional tissue engineering (FTE) has promoted the use of physiologic loading bioreactor systems to cultivate engineered tissues with load-bearing properties. Prior studies have demonstrated that culturing agarose constructs seeded with primary bovine chondrocytes from immature joints, and subjected to dynamic deformation, produced equilibrium compressive properties and proteoglycan content matching the native tissue. In the process of translating these results to an adult canine animal model, it was found that protocols previously successful with immature bovine primary chondrocytes did not produce the same successful outcome when using adult canine primary chondrocytes. The objective of this study was to assess the efficacy of a modified FTE protocol using adult canine chondrocytes seeded in agarose hydrogel and subjected to dynamic loading. Two modes of dynamic loading were applied to constructs using custom bioreactors: unconfined axial compressive deformational loading (DL; 1 Hz, 10% deformation) or sliding contact loading (Slide; 0.5 Hz, 10% deformation). Loading for 3 h daily was initiated on day 0, 14, or 28 (DL0, DL14, DL28, and Slide14). Constructs with applied loading (both DL and Slide) exhibited significant increases in Young's modulus compared with free-swelling control as early as day 28 in culture (p < 0.05). However, glycosaminoglycan, collagen, and DNA content were not statistically different among the various groups. The modulus values attained for engineered constructs compare favorably with (and exceed in some cases) those of native canine knee (patella groove and condyle) cartilage. Our findings successfully demonstrate an FTE strategy incorporating clinically relevant, adult chondrocytes and gel scaffold for engineering cartilage replacement tissue. These results, using continuous growth factor supplementation, are in contrast to our previously reported studies with immature chondrocytes where the sequential application of dynamic loading after transient transforming growth factor-beta3 application was found to be a superior culture protocol. Sliding, which simulates aspects of joint articulation, has shown promise in promoting engineered tissue development and provides an alternative option for FTE of cartilage constructs to be further explored.
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