Anterior cruciate ligament (ACL) is difficult to heal after injury due to the dynamic fluid environment of joint. Previously, we have achieved satisfactory regeneration of subcutaneous tendon/ligament with knitted silk-collagen sponge scaffold due to its specific "internal-space-preservation" property. This study aims to investigate the long-term effects of knitted silk-collagen sponge scaffold on ACL regeneration and osteoarthritis prevention. The knitted silk-collagen sponge scaffold was fabricated and implanted into a rabbit ACL injury model. The knitted silk-collagen sponge scaffold was found to enhance migration and adhesion of spindle-shaped cells into the scaffold at 2 months post-surgery. After 6 months, ACL treated with the knitted silk-collagen sponge scaffold exhibited increased expression of ligament genes and better microstructural morphology. After 18 months, the knitted silk-collagen sponge scaffold-treated group had more mature ligament structure and direct ligament-to-bone healing. Implanted knitted silk-collagen sponge scaffolds degraded much more slowly compared to subcutaneous implantation. Furthermore, the knitted silk-collagen sponge scaffold effectively protected joint surface cartilage and preserved joint space for up to 18 months post-surgery. These findings thus demonstrated that the knitted silk-collagen sponge scaffold can regenerate functional ACL and prevent osteoarthritis in the long-term, suggesting its clinical use as a functional bioscaffold for ACL reconstruction.
Meniscus injury is frequently encountered in clinical practice. Current surgical therapy involving partial or complete meniscectomy relieves pain in the short-term but often leads to osteoarthritis (OA) in the long-term. In this study, we report a new strategy of articular cartilage protection by intra-articular injection of novel human meniscus stem/progenitor cells (hMeSPCs). We found that hMeSPCs displayed both mesenchymal stem cell characteristics and high expression levels of collagen II. In the rat meniscus injury model, hMeSPC transplantation not only led to more neo-tissue formation and better-defined shape but also resulted in more rounded cells and matured extracellular matrix. Stromal cell-derived factor-1 (SDF-1) enhanced the migration of hMeSPCs, whereas AMD3100 abolished the chemotactic effects of SDF-1 on hMeSPCs, both in vitro and in vivo. In an experimental OA model, transplantation of hMeSPCs effectively protected articular cartilage, as evidenced by reduced expression of OA markers such as collagen I, collagen X, and hypoxia-inducible factor 2? but increased expression of collagen II. Our study demonstrated for the first time that intra-articular injection of hMeSPCs enhanced meniscus regeneration through the SDF-1/CXCR4 axis. Our study highlights a new strategy of intra-articular injection of hMeSPCs for meniscus regeneration.
The hearing and echolocation clicks of a stranded Indo-Pacific humpback dolphin (Sousa chinensis) in Zhuhai, China, were studied. This animal had been repeatedly observed in the wild before it was stranded and its age was estimated to be ~40 years. The animals hearing was measured using a non-invasive auditory evoked potential (AEP) method. Echolocation clicks produced by the dolphin were recorded when the animal was freely swimming in a 7.5 m (width)×22 m (length)×4.8 m (structural depth) pool with a water depth of ~2.5 m. The hearing and echolocation clicks of the studied dolphin were compared with those of a conspecific younger individual, ~13 years of age. The results suggested that the cut-off frequency of the high-frequency hearing of the studied dolphin was ~30-40 kHz lower than that of the younger individual. The peak and centre frequencies of the clicks produced by the older dolphin were ~16 kHz lower than those of the clicks produced by the younger animal. Considering that the older dolphin was ~40 years old, its lower high-frequency hearing range with lower click peak and centre frequencies could probably be explained by age-related hearing loss (presbycusis).
Two mixed-NH3/amine platinum (II) complexes of 3-dichoroacetoxylcyclobutane-1, 1-dicarboxylate have been prepared in the present study and characterized by elemental analysis and IR, HPLC-MS and (1)H, (13)C-NMR. The complexes exist in equilibrium between two position isomeric forms and undergo hydrolysis reaction in aqueous solution, releasing the platinum pharmacophores and dichloroacetate which is a small-molecular cell apoptosis inducer. Both complexes were evaluated for in vitro cytotoxic profile in A549, SGC-7901 and SK-OV-3 cancer cells as well as in BEAS-2B normal cells. They exhibit markedly cytotoxicity toward cancer cells by selectively inducing the apoptosis of cancer cells, whereas leaving normal cells less affected. They have also the ability to overcome the resistance of SK-OV-3 cancer cells to cisplatin. Our findings offer an alternative novel way to develop platinum drugs which can both overcome the drug resistance and selectively target tumor cells.
The repair of osteochondral defects can be enhanced with scaffolds but is often accompanied with undesirable terminal differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). Parathyroid hormone-related protein (PTHrP) has been shown to inhibit aberrant differentiation, but administration at inappropriate time points would have adverse effects on chondrogenesis. This study aims to develop an effective tissue engineering strategy by combining PTHrP and collagen-silk scaffold for osteochondral defect repair. The underlying mechanisms of the synergistic effect of combining PTHrP administration with collagen-silk scaffold implantation for rabbit knee joint osteochondral defect repair were investigated. In vitro studies showed that PTHrP treatment significantly reduced Alizarin Red staining and expression of terminal differentiation-related markers. This is achieved in part through blocking activation of the canonical Wnt/?-catenin signaling pathway. For the in vivo repair study, intra-articular injection of PTHrP was carried out at three different time windows (4-6, 7-9 and 10-12 weeks) together with implantation of a bi-layer collagen-silk scaffold. Defects treated with PTHrP at the 4-6 weeks time window exhibited better regeneration (reconstitution of cartilage and subchondral bone) with minimal terminal differentiation (hypertrophy, ossification and matrix degradation), as well as enhanced chondrogenesis (cell shape, Col2 and GAG accumulation) compared with treatment at other time windows. Furthermore, the timing of PTHrP administration also influenced PTHrP receptor expression, thus affecting the treatment outcome. Our results demonstrated that intra-articular injection of PTHrP at 4-6 weeks post-injury together with collagen-silk scaffold implantation is an effective strategy for inhibiting terminal differentiation and enhancing chondrogenesis, thus improving cartilage repair and regeneration in a rabbit model.
Meniscus injury is frequently encountered in clinical practice. Current surgical therapy involving partial or complete meniscectomy relieves pain in the short-term but often leads to osteoarthritis (OA) in the long-term. Here, this study aimed to identify and characterize a novel population of meniscus-derived stem cells (MeSCs) and develop a new strategy of articular cartilage protection by intra-articular injection of these cells. The "stemness" and immune properties of MeSCs were investigated in vitro, while the efficacy of intra-articular injection of MeSCs for meniscus regeneration and OA prevention were investigated in vivo at 4, 8, and 12 weeks postsurgery. MeSCs displayed typical stem cell characteristics such as low immunogenicity and even possessed immunosuppressive function. In a rabbit meniscus injury model, transplantation of allogenous MeSCs did not elicit immunological rejection, but promoted neo-tissue formation with better-defined shape and more matured extracellular matrix. In a rabbit experimental OA model, transplantation of MeSCs further protected joint surface cartilage and maintained joint space at 12 weeks postsurgery, whereas extensive joint surface irregularities and joint space stenosis were observed in the control group. This study thus evoked a new strategy for articular cartilage protection and meniscus regeneration by intra-articular injection of MeSCs for patients undergoing meniscectomy.
The marine mammalian Indo-Pacific humpback dolphin, once widely lived in waters of the Indian to western Pacific oceans, has become an endangered species. The individual number of this dolphin has significantly declined in recent decades, which raises the concern of extinction. Direct concentration on laboratorial conservation of the genetic and cell resources should be paid to this marine species. Here, we report the successful derivation of cell lines form the skin of Indo-Pacific humpback dolphin. The cell cultures displayed the characteristics of fibroblast in morphology and grew rapidly at early passages, but showed obvious growth arrest at higher passages. The karyotype of the cells consisted of 42 autosomes and sex chromosomes X and Y. The immortalized cell lines obtained by forced expression of the SV40 large T-antigen were capable of proliferation at high rate in long-term culture. Immortalization and long-term culture did not cause cytogenetically observable abnormality in the karyotype. The cell type of the primary cultures and immortalized cell lines were further characterized as fibroblasts by the specific expression of vimentin. Gene transfer experiments showed that exogenetic genes could be efficiently delivered into the cells by both plasmid transfection and lentivirus infection. The cells derived from the skin of the Indo-Pacific humpback dolphin may serve as a useful in vitro system for studies on the effects of environmental pollutants and pathogens in habitats on the dolphin animals. More importantly, because of their high proliferation rate and susceptibility to lentivirus, these cells are potential ideal materials for generation of induced pluripotent stem cells.
The Indo-Pacific humpback dolphin (Sousa chinensis), a marine mammal species inhabited in the waters of Southeast Asia, South Africa and Australia, has attracted much attention because of the dramatic decline in population size in the past decades, which raises the concern of extinction. So far, this species is poorly characterized at molecular level due to little sequence information available in public databases. Recent advances in large-scale RNA sequencing provide an efficient approach to generate abundant sequences for functional genomic analyses in the species with un-sequenced genomes.
A novel influenza A virus strain (H1N1-2009) spread first in Mexico and the United Stated in late April 2009, leading to the first influenza pandemic of the 21(st) century. The objective of this study was to determine the epidemiological and virological characteristics of the pandemic influenza A (H1N1-2009) in Zhanjiang, China.
Taxonomy within genus Sousa is confused largely due to inconsistencies among external morphology, skull morphology, pigmentation patterns and molecular studies. Here we provide our understanding of the evolution of Sousa chinensis by proposing a phylogeographic history based on mtDNA study. It is proposed that the species originated in eastern Australian waters and the current distribution has taken shape over the last 8.02-1.24 million years. Populations in Southeast Asia and Australian region experienced recent expansion about 0.54-1.5 million years ago. It is also proposed that populations in Southeast Asia experienced separation, re-unification and further dispersal during the last glacial age with multiple north-south migration across the Sahul Shelf area of northern Australia.
This study developed a bioactive knitted silk-collagen sponge scaffold by incorporation of exogenous SDF-1 alpha, to enable selective migration and homing of cells for in situ tendon regeneration. With in vitro studies, it was observed that CXCR4 gene expression and migration of bone mesenchymal stromal cells and hypo-dermal fibroblasts were more sensitive to exogenous SDF-1 alpha, while expression of tendon repair gene markers by hypo-dermal fibroblasts and Achilles tendon fibroblasts were more sensitive to exogenous SDF-1 alpha. With a rat Achilles tendon injury model, exogenous SDF-1 alpha was shown to reduce infiltration of inflammatory cells and enhance migration of fibroblast-like cells into the scaffold at 4 days and 1 week post-surgery. After 4 weeks, SDF-1 alpha treated tendon had increased expression of tendon repair gene markers and endogenous SDF-1 alpha, exhibited more physiological microstructures with larger diameter collagen fibrils, and had better biomechanical properties than the control group. Hence, our bioactive scaffold improved efficacy of tendon regeneration by increasing the recruitment of fibroblast-like cells, enhancing local endogenous SDF-1 alpha and tendon extracellular matrix production, and decreasing accumulation of inflammatory cells. Incorporation of SDF-1 alpha within a knitted silk-collagen sponge scaffold can therefore be a practical application for tendon tissue engineering.
Despite the presence of cartilage-derived mesenchymal stem cells (C-MSCs) and synovial membrane-derived mesenchymal stem cells (SM-MSCs) populations, partial-thickness cartilage defects, in contrast to the full-thickness defects, are devoid of spontaneous repair capacity. This study aims to create an in situ matrix environment conducive to C-MSCs and SM-MSCs to promote cartilage self-repair. Spontaneous repair with MSCs migration into the defect area was observed in full-thickness defects, but not in partial-thickness defects in rabbit model. Ex vivo and in vitro studies showed that subchondral bone or type 1 collagen (col1) scaffold was more permissive for MSCs adhesion than cartilage or type 2 collagen (col2) scaffold and induced robust stromal cell-derived factors-1 (SDF-1) dependent migration of MSCs. Furthermore, creating a matrix environment with col1 scaffold containing SDF-1 enhanced in situ self-repair of partial-thickness defects in rabbit 6 weeks post-injury. Hence, the inferior self-repair capacity in partial-thickness defects is partially owing to the non-permissive matrix environment. Creating an in situ matrix environment conducive to C-MSCs and SM-MSCs migration and adhesion with col1 scaffold containing SDF-1 can be exploited to improve self-repair capacity of cartilage.
ABSTRACT: Cartilage repair tissue is usually accompanied by chondrocyte hypertrophy and osseous overgrowths, and a role for parathyroid hormone-related protein (PTHrP) in inhibiting chondrocytes from hypertrophic differentiation during the process of endochondral ossification has been demonstrated. However, application of PTHrP in cartilage repair has not been extensively considered. This review systemically summarizes for the first time the inhibitory function of PTHrP on chondrocyte hypertrophy in articular cartilage and during the process of endochondral ossification, as well as the process of mesenchymal stem cell chondrogenic differentiation. Based on the literature review, the strategy of using PTHrP for articular cartilage repair is suggested, which is instructive for clinical treatment of cartilage injuries as well as osteoarthritis.
A 45-year-old HIV-negative man was treated with intravenous etimicin sulphate for an unintentionally found, non-tender neck mass at a local outpatient clinic. His symptoms seemed improved initially. However, the unilateral mass subsequently became enlarged quickly and painful. Spontaneous discharge occurred after admission to our department. The smear of the pus from surgical drainage was positive for acid-fast bacilli and the presence of Mycobacterium tuberculosis was confirmed by culture. He was diagnosed with an acute paradoxical reaction (PR) of cervical tuberculous lymphadenitis. Our case was unusual in that acute PR of tuberculosis was caused by receiving single aminoglycoside agent which has not been proven to have therapeutic effect on TB infection and it is also the first case of PR induced by etimicin. The patient recovered well from a 6-month antituberculosis chemotherapy.
Tendon stem/progenitor cells (TSPCs) were recently identified within tendon tissues. The aim of this study was to investigate TSPC-seeded knitted silk-collagen sponge scaffold for functional shoulder repair. The multidifferentiation potential, proliferation, and immune properties of TSPCs were investigated in vitro, while the efficacy of TSPC-seeded knitted silk-collagen sponge scaffolds in promoting rotator cuff regeneration was evaluated in vivo within a rabbit model. TSPCs, which exhibited universal stem cell characteristics (i.e., clonogenicity, high proliferative capacity, and multidifferentiation potential), nonimmunogenicity, and immunosuppression, proliferated well on our scaffold in vitro. Implantation of allogenous TSPC-seeded scaffolds within a rabbit rotator cuff injury model did not elicit an immunological reaction, but instead increased fibroblastic cell ingrowth and reduced infiltration of lymphocytes within the implantation sites at 4 and 8 weeks postsurgery. After 12 weeks, the allogenous TSPC-treated group exhibited increased collagen deposition and had better structural and biomechanical properties compared to the control group. This study thus demonstrated that the allogenous TSPC-seeded knitted silk-collagen sponge scaffold enhanced the efficacy of rotator cuff tendon regeneration by differentiating into tenocytes, and by secreting anti-inflammatory cytokines that prevent immunological rejection. Hence, allogenous TSPC-seeded knitted silk-collagen sponge scaffolds can be a clinically useful application for tendon tissue engineering.
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