To investigate the relationship between tendinopathy and higher production of prostaglandins E2 (PGE2) and leukotriene B4(LTB4) induced by cyclic stretching of human patellar tendon fibroblasts.Methods We used a novel...To investigate the relationship between tendinopathy and higher production of prostaglandins E2 (PGE2) and leukotriene B4(LTB4) induced by cyclic stretching of human patellar tendon fibroblasts.Methods We used a novel in vitro model system to mimic in vivo conditions,where human patellar tendon fibroblasts (HPTFs) were uniaxially stretched with different magnitudes of stretching (4%,8% and 12%).Non-stretched fibroblasts were used as control.The productions of PGE2 and LTB4 as well as the expression of cycloxygenase (COX) and 5-lipoxygenase (5-LO) were then measured every four hours of cyclic stretching.In addition,we treated the cells with inhibitors of COX or 5-LO.Results It was found that cyclic stretching of fibroblasts at 8% and 12% of stretching increased PGE2 and LTB4 levels.Blocking the COX enzyme with indomethacin (25 mol/L) decreased PGE2 levels but increased LTB4 production and vice versa.Whereas decreasing LTB4 production with MK-886 (10 μmol/L) could increase PGE2 levels compared to cells tretched without inhibitors.Conclusion Cyclic stretching of HPTFs produces high levels of PGE2 and LTB4,where a balance exists:blocking PGE2 production increases the production of LTB4,and vice versa.Therefore,this study raises the possibility that the routine use of COX inhibitors in clinical treatment of tendinopathy may exacerbate the condition by causing neutrophil-mediated inflammatory and degenerative changes in the tendon due to increased levels of LTB4,which is a potent chemoattractant for neutrophils.17 refs,3 figs.展开更多
We analyze the crucial biochemical and biophysical properties of the basic constituents—connective tissues (CT), and interstitial fluid (IF) constituting the non-cellular part of the fascia. We provide ample evidence...We analyze the crucial biochemical and biophysical properties of the basic constituents—connective tissues (CT), and interstitial fluid (IF) constituting the non-cellular part of the fascia. We provide ample evidence that the resident cells and cells in transit in the fascia are continuously interacting with the non-cellular constituents to form an active organ with well-defined functions. We show evidence that pathological states of diseases of internal organs, as well as that of the constituents of the fascia itself, manifest in certain CTIF domains of the fascia. Numerous diseases originate from imbalance of the digestion and synthesis of the native collagen triple helices. Review on the scanning electron microscopy examination of cross-section of tendons indicates that micro-fibrils of collagen I form regular geometrical structures, supporting the hypothesis that the collagen fibrils assemble like liquid crystals. Information on the age of Achilles tendons has been reported, based on dating of the 14C atoms generated from the nuclear bomb tests in 1955-1963. The causes of spontaneous tendon rupture and tendinopathy are analyzed. Plausible clinical measures to treat tendinopathy are briefly discussed, including the application of synthetic mechano-growth factor, glyceryl trinitrate patch (to supply nitric oxide), platelet rich plasma, proteomic profile analysis and microRNA 29a therapy.展开更多
文摘To investigate the relationship between tendinopathy and higher production of prostaglandins E2 (PGE2) and leukotriene B4(LTB4) induced by cyclic stretching of human patellar tendon fibroblasts.Methods We used a novel in vitro model system to mimic in vivo conditions,where human patellar tendon fibroblasts (HPTFs) were uniaxially stretched with different magnitudes of stretching (4%,8% and 12%).Non-stretched fibroblasts were used as control.The productions of PGE2 and LTB4 as well as the expression of cycloxygenase (COX) and 5-lipoxygenase (5-LO) were then measured every four hours of cyclic stretching.In addition,we treated the cells with inhibitors of COX or 5-LO.Results It was found that cyclic stretching of fibroblasts at 8% and 12% of stretching increased PGE2 and LTB4 levels.Blocking the COX enzyme with indomethacin (25 mol/L) decreased PGE2 levels but increased LTB4 production and vice versa.Whereas decreasing LTB4 production with MK-886 (10 μmol/L) could increase PGE2 levels compared to cells tretched without inhibitors.Conclusion Cyclic stretching of HPTFs produces high levels of PGE2 and LTB4,where a balance exists:blocking PGE2 production increases the production of LTB4,and vice versa.Therefore,this study raises the possibility that the routine use of COX inhibitors in clinical treatment of tendinopathy may exacerbate the condition by causing neutrophil-mediated inflammatory and degenerative changes in the tendon due to increased levels of LTB4,which is a potent chemoattractant for neutrophils.17 refs,3 figs.
文摘We analyze the crucial biochemical and biophysical properties of the basic constituents—connective tissues (CT), and interstitial fluid (IF) constituting the non-cellular part of the fascia. We provide ample evidence that the resident cells and cells in transit in the fascia are continuously interacting with the non-cellular constituents to form an active organ with well-defined functions. We show evidence that pathological states of diseases of internal organs, as well as that of the constituents of the fascia itself, manifest in certain CTIF domains of the fascia. Numerous diseases originate from imbalance of the digestion and synthesis of the native collagen triple helices. Review on the scanning electron microscopy examination of cross-section of tendons indicates that micro-fibrils of collagen I form regular geometrical structures, supporting the hypothesis that the collagen fibrils assemble like liquid crystals. Information on the age of Achilles tendons has been reported, based on dating of the 14C atoms generated from the nuclear bomb tests in 1955-1963. The causes of spontaneous tendon rupture and tendinopathy are analyzed. Plausible clinical measures to treat tendinopathy are briefly discussed, including the application of synthetic mechano-growth factor, glyceryl trinitrate patch (to supply nitric oxide), platelet rich plasma, proteomic profile analysis and microRNA 29a therapy.
