Considerations in hiPSC-derived cartilage for articular cartilage repair

Background: A lack of cell or tissue sources hampers regenerative medicine for articular cartilage damage. Main text: We review and discuss the possible use of pluripotent stem cells as a new source for future clinical use. Human induced pluripotent stem cells (hiPSCs) have several advantages over human embryonic stem cells (hESCs). Methods for the generation of chondrocytes and cartilage from hiPSCs have been developed. To reduce the cost of this regenerative medicine, allogeneic transplantation is preferable. hiPSC-derived cartilage shows low immunogenicity like native cartilage, because the cartilage is avascular and chondrocytes are segregated by the extracellular matrix. In addition, we consider our experience with the aberrant deposition of lipofuscin or melanin on cartilage during the chondrogenic differentiation of hiPSCs. Short conclusion: Cartilage generated from allogeneic hiPSC-derived cartilage can be used to repair articular cartilage damage

Potential for Tumorigenesis and Repair of Osteochondral Defects by iPS Cell Transplantation in Rat

Abstract Articular cartilage repair remains a challenge in the field of orthopedic medicine. Cell-based therapy for cartilage repair, such as autologous chondrocyte implantation, was established in the 1990s. However, the issue of the source from which the lesion-targeting cells are harvested remains a limitation of this approach as larger lesions require more cells for repair, and thus, more healthy tissue must be damaged to harvest the needed cells. Reprogramming of induced pluripotent stem (iPS) cells is a promising tool for cell-based regenerative therapy because of their proliferative capacity and pluripotency; however, these characteristics also create a risk of tumorigenesis. This study aimed to determine the probability of iPS cell-derived tumor occurrence as a function of injection or transplantation site, and to assess whether transplanted iPS cells can promote cartilage defect repair. Pluripotent mouse iPS cells (5x10 6 cells/ml) were subcutaneously injected or transplanted into experimentally induced lesions in the knee cartilage of immunodeficient rats. Subcutaneous teratoma formation was observed in 30% of animals (3 of 10) at 4weeks, and 41% of animals (7 of 17) at 12 weeks after iPS cell injection. Cartilage repair as indicated by modified Wakitani's score was similar in the cell-free group and in the iPS cell implantation group at 4 weeks [11.8 ± 1.8 (n = 8) vs. 10.3 ± 2.8 (n = 18)]. iPS cell implantation yielded a score of 7.8 ± 2.0 (n = 10) at 12 weeks, significantly better than the cell-free group [10.5 ± 0.6 (n = 4)]. There was no macro-or microscopic evidence of tumor formation at the cartilage repair site after iPS cell implantation. Although we could not use the iPS cells directly for cartilage repair, the results of our study indicate the potential for a new therapy for cartilage repair by developing iPS reprogramming technology

The Wnt Antagonist Frzb-1 Regulates Chondrocyte Maturation and Long Bone Development during Limb Skeletogenesis

AbstractThe Wnt antagonist Frzb-1 is expressed during limb skeletogenesis, but its roles in this complex multistep process are not fully understood. To address this issue, we determined Frzb-1 gene expression patterns during chick long bone development and carried out gain- and loss-of-function studies by misexpression of Frzb-1, Wnt-8 (a known Frzb-1 target), or different forms of the intracellular Wnt mediator LEF-1 in developing limbs and cultured chondrocytes. Frzb-1 expression was quite strong in mesenchymal prechondrogenic condensations and then characterized epiphyseal articular chondrocytes and prehypertrophic chondrocytes in growth plates. Virally driven Frzb-1 misexpression caused shortening of skeletal elements, joint fusion, and delayed chondrocyte maturation, with consequent inhibition of matrix mineralization, metalloprotease expression, and marrow/bone formation. In good agreement, misexpression of Frzb-1 or a dominant-negative form of LEF-1 in cultured chondrocytes maintained the cells at an immature stage. Instead, misexpression of Wnt-8 or a constitutively active LEF-1 strongly promoted chondrocyte maturation, hypertrophy, and calcification. Immunostaining revealed that the distribution of endogenous Wnt mediator β-catenin changes dramatically in vivo and in vitro, from largely cytoplasmic in immature proliferating and prehypertrophic chondrocytes to nuclear in hypertrophic mineralizing chondrocytes. Misexpression of Frzb-1 prevented β-catenin nuclear relocalization in chondrocytes in vivo or in vitro. The data demonstrate that Frzb-1 exerts a strong influence on limb skeletogenesis and is a powerful and direct modulator of chondrocyte maturation, phenotype, and function. Phases of skeletogenesis, such as terminal chondrocyte maturation and joint formation, appear to be particularly dependent on Wnt signaling and thus very sensitive to Frzb-1 antagonistic action

CCN3 and bone marrow cells

CCN3 expression was observed in a broad variety of tissues from the early stage of development. However, a kind of loss of function in mice (CCN3 del VWC domain -/-) demonstrated mild abnormality, which indicates that CCN3 may not be critical for the normal embryogenesis as a single gene. The importance of CCN3 in bone marrow environment becomes to be recognized by the studies of hematopoietic stem cells and Chronic Myeloid Leukemia cells. CCN3 expression in bone marrow has been denied by several investigations, but we found CCN3 positive stromal and hematopoietic cells at bone extremities with a new antibody although they are a very few populations. We investigated the expression pattern of CCN3 in the cultured bone marrow derived mesenchymal stem cells and found its preference for osteogenic differentiation. From the analyses of in vitro experiment using an osteogenic mesenchymal stem cell line, Kusa-A1, we found that CCN3 downregulates osteogenesis by two different pathways; suppression of BMP and stimulation of Notch. Secreted CCN3 from Kusa cells inhibited the differentiation of osteoblasts in separate culture, which indicates the paracrine manner of CCN3 activity. CCN3 may also affect the extracellular environment of the niche for hematopoietic stem cells

シセイ ガ セキ ノ サイダイ リュウリョウ (Cough Peak Flow) ト コキキン カツドウ ニ アタエル エイキョウ

【目的】姿勢が咳の最大流量(CPF)や咳嗽時呼気筋活動, 呼吸筋力や肺活量にどのような影響を与えるのかを調査することを目的とした. 【方法】健常成人男性17名を対象に背臥位, ベッドアップ45度, 端座位の3姿勢でCPF, 呼吸筋力, 肺活量を計測し, CPF測定時のみ呼気筋(外腹斜筋, 腹直筋)の活動を記録した. 筋活動の評価は, 事前に最大随意収縮時の筋積分値(最大iEMG)を求め, 咳嗽時筋活動を最大iEMGに対する百分率(%iEMG)として評価した. 【結果】CPF, 肺活量, 外腹斜筋の%iEMGは端座位が最も高く, 次いで45度座位, 背臥位の順であり, 端座位と他の姿勢との間には全て有意差を認めた(P<0.05). 腹直筋の%iEMGは姿勢による変化を認めなかった. 【考察】CPFを始め, ほとんどの項目で端座位が最も高く, 背臥位で最低値となり, 姿勢の影響を受けることが明らかになった. 効果的な咳嗽を行なうには背臥位よりも, できるかぎり端座位に近い姿勢で行なうことが望ましいと考えられた.Purpose: The purpose of this study was to investigate the effect of posture on cough peak flow (CPF), electromyographic (EMG) activity of the abdominal muscles (external abdominal oblique muscles, EO; rectus abdominis muscles, RA), respiratory muscle strength (maximum expiratory and inspiratory pressure, PEmax and PImax), and vital capacity (VC). Methods: Seventeen normal adult men participated in this study. We measured the CPF, EMG activities of the EO and RA during coughing, PEmax, PEmax, and VC in the following 3 postures: supine, 45 degrees head-up, and sitting. The raw EMG data were rectified, and the integrated EMG data were normalized relative to the values obtained during maximum voluntary contractions (%iEMG). Results: CPF, %iEMG of the EO, PImax, PEmax, and VC were higher in the sitting position than in any of the other positions. The %iEMG of the RA did not change with posture. Conclusion: These results suggest that CPF, %iEMG of the EO, PImax, PEmax, and VC are affected by the posture, and that it is preferable to adopt a more head-up position for effective coughing

Considerations in hiPSC-derived cartilage for articular cartilage repair

Abstract Background A lack of cell or tissue sources hampers regenerative medicine for articular cartilage damage. Main text We review and discuss the possible use of pluripotent stem cells as a new source for future clinical use. Human induced pluripotent stem cells (hiPSCs) have several advantages over human embryonic stem cells (hESCs). Methods for the generation of chondrocytes and cartilage from hiPSCs have been developed. To reduce the cost of this regenerative medicine, allogeneic transplantation is preferable. hiPSC-derived cartilage shows low immunogenicity like native cartilage, because the cartilage is avascular and chondrocytes are segregated by the extracellular matrix. In addition, we consider our experience with the aberrant deposition of lipofuscin or melanin on cartilage during the chondrogenic differentiation of hiPSCs. Short conclusion Cartilage generated from allogeneic hiPSC-derived cartilage can be used to repair articular cartilage damage

Absolute evaluation of internal and external quantum efficiencies and light extraction efficiency in InGaN single quantum wells by simultaneous photoacoustic and photoluminescence measurements combined with integrating-sphere method

ABSTRACTSeparated evaluation of factors in the external quantum efficiency (EQE) is important in order to improve the characteristics of semiconductors optical devices. Especially, the internal quantum efficiency (IQE) is an important value which indicates crystal quality of the active layers, and an accurate method for estimating the IQE values is required. The IQE is usually estimated from temperature dependence of photoluminescence (PL) intensity by assuming that the IQE at cryogenic temperature is 100%. However, III-nitride semiconductor materials, used in many optical devices, usually have large defect density, and the assumption is not necessarily valid. In our previous report, we demonstrated the simultaneous photoacoustic (PA) and PL measurements to accurately estimate the IQE values in GaN films with various qualities and obtained reasonable results. In this work, we have successfully realized reproducible measurements with high accuracy for an InGaN-QW sample by suppressing the background noise significantly. Furthermore, we have also measured the values of EQE by using an integrating-sphere. Since the light extraction efficiency (LEE) can be obtained by the values of IQE and EQE, it has been shown that the overall picture of emission efficiency can be provided by our method