Differentiating the extent of cartilage repair in rabbit ears using nonlinear optical microscopy

Nonlinear optical microscopy (NLOM) was used as a noninvasive and label‐free tool to detect and quantify the extent of the cartilage recovery. Two cartilage injury models were established in the outer ears of rabbits that created a different extent of cartilage recovery based on the presence or absence of the perichondrium. High‐resolution NLOM images were used to measure cartilage repair, specifically through spectral analysis and image texture. In contrast to a wound lacking a perichondrium, wounds with intact perichondria demonstrated significantly larger TPEF signals from cells and matrix, coarser texture indicating the more deposition of type I collagen. Spectral analysis of cells and matrix can reveal the matrix properties and cell growth. In addition, texture analysis of NLOM images showed significant differences in the distribution of cells and matrix of repaired tissues with or without perichondrium. Specifically, the decay length of autocorrelation coefficient based on TPEF images is 11.2 ± 1.1 in Wound 2 (with perichondrium) and 7.5 ± 2.0 in Wound 1 (without perichondrium), indicating coarser image texture and faster growth of cells in repaired tissues with perichondrium (p < 0.05). Moreover, the decay length of autocorrelation coefficient based on collagen SHG images also showed significant difference between Wound 2 and 1 (16.2 ± 1.2 vs. 12.2 ± 2.1, p < 0.05), indicating coarser image texture and faster deposition of collagen in repaired tissues with perichondrium (Wound 2). These findings suggest that NLOM is an ideal tool for studying cartilage repair, with potential applications in clinical medicine. NLOM can capture macromolecular details and distinguish between different extents of cartilage repair without the need for labelling agents.     

Evaluation of a superior lubrication mechanism with biphasic hydrogels for artificial cartilage

To extend the durability of artificial joints, biomimetic artificial hydrogel cartilage is proposed as a way of improving the lubrication mechanism in artificial joints. The application of hydrogels with properties similar to those of articular cartilage can be expected to duplicate the superior load-carrying capacity and lubricating ability of natural synovial joints. Frictional behaviors with three kinds of poly(vinyl alcohol) (PVA) hydrogels with high water content were examined in reciprocating tests. Interstitial fluid pressure, von Mises stress and fluid flow were compared in biphasic finite element analysis, and frictional behavior was evaluated in terms of biphasic lubrication and surface lubricity. Hybrid gel prepared by a combination of cast-drying and freeze-thawing methods showed superior low friction.     

Nutraceutical therapies for degenerative joint diseases: a critical review

There is growing recognition of the importance of nutritional factors in the maintenance of bone and joint health, and that nutritional imbalance combined with endocrine abnormalities may be involved in the pathogenesis of osteoarthritis (OA) and osteochondritis dissecans (OCD). Despite this, dietary programs have played a secondary role in the management of these connective tissue disorders. Articular cartilage is critically dependent upon the regular provision of nutrients (glucose and amino acids), vitamins (particularly vitamin C), and essential trace elements (zinc, magnesium, and copper). Therefore, dietary supplementation programs and nutraceuticals used in conjunction with non-steroidal, anti-inflammatory drugs (NSAIDs) may offer significant benefits to patients with joint disorders, such as OA and OCD. This article examines the available clinical evidence for the efficacy of nutraceuticals, antioxidant vitamin C, polyphenols, essential fatty acids, and mineral cofactors in the treatment of OA and related joint disorders in humans and veterinary species. This article also attempts to clarify the current state of knowledge. It also highlights the need for additional targeted research to elucidate the changes in nutritional status and potential alterations to the expression of plasma membrane transport systems in synovial structures in pathophysiological states, so that current therapy and future treatments may be better focused.     

鲟鱼软骨成分分析及营养评价

对养殖西伯利亚鲟鱼头骨与脊骨软骨中营养成分组成情况进行比较分析。结果表明:鲟鱼头骨中糖分及蛋白质的含量略高于脊骨,脂肪含量则低于脊骨。头骨和脊骨蛋白质的氨基酸组成基本一致的,均有18种氨基酸,其中甘氨酸、谷氨酸和脯氨酸的含量较高,色氨酸为第一限制性氨基酸,必需氨基酸含量均接近或超过WHO推荐的成人氨基酸需要量模式。鲟鱼软骨中还含有丰富的对人体有益微量元素。     

Stepwise Proliferation and Chondrogenic Differentiation of Mesenchymal Stem Cells in Collagen Sponges under Different Microenvironments

Biomimetic microenvironments are important for controlling stem cell functions. In this study, different microenvironmental conditions were investigated for the stepwise control of proliferation and chondrogenic differentiation of human bone-marrow-derived mesenchymal stem cells (hMSCs). The hMSCs were first cultured in collagen porous sponges and then embedded with or without collagen hydrogels for continual culture under different culture conditions. The different influences of collagen sponges, collagen hydrogels, and induction factors were investigated. The collagen sponges were beneficial for cell proliferation. The collagen sponges also promoted chondrogenic differentiation during culture in chondrogenic medium, which was superior to the effect of collagen sponges embedded with hydrogels without loading of induction factors. However, collagen sponges embedded with collagen hydrogels and loaded with induction factors had the same level of promotive effect on chondrogenic differentiation as collagen sponges during in vitro culture in chondrogenic medium and showed the highest promotive effect during in vivo subcutaneous implantation. The combination of collagen sponges with collagen hydrogels and induction factors could provide a platform for cell proliferation at an early stage and subsequent chondrogenic differentiation at a late stage. The results provide useful information for the chondrogenic differentiation of stem cells and cartilage tissue engineering.     

A Simple Quality Evaluation Method for Proteoglycan after Addition to Beverages

Over the past 10 years, many products utilizing the functionality of salmon cartilage proteoglycan have come on the market, and consumer awareness of proteoglycan has increased. During this period, the biggest issue has been how to evaluate the amount and quality of proteoglycan in the cartilage extract blended in the products. In this study, we propose an immunological method that can easily evaluate the amount and quality of proteoglycan in the proteoglycan-containing compositions. By the present method, it is possible to evaluate not only the retention of the functional domains of the core protein of proteoglycan, but also that of chondroitin sulfate chains linked to the core protein. Furthermore, the binding activity of proteoglycan to hyaluronan can be evaluated if hyaluronan is used as a probe instead of an antibody. This method is expected to be useful for proteoglycan quality evaluation during the manufacturing process and product storage.     

Pannus-induced destruction of joint cartilage and subchondral bone. Visualization and staging by MRI

To investigate whether characterization and reliable staging of pannus-induced cartilage destructions in the knee could be achieved by magnetic resonance imaging (MRI), we examined 13 patients with arthritis, 2 patients with osteoarthritis (OA) and 5 healthy controls. A regional staging of bone and cartilage erosions was performed by two independent observers. In each of six regions, pannus-induced cartilage erosions were staged 0 (not present), 1 (present, but not penetrating), or 2 (penetrating).Pannus-induced cartilage erosions were demonstrated by MRI in 11 patients with arthritis and in no controls or OA patients. In the 11 patients, synovial masses overlying joint cartilage and a corresponding thinning of the cartilage, reflecting degradation, could be precisely delimited following gadolinium-DTPA I.V. Eight patients had bone erosions on MRI, either marginal caused by direct synovial invasion and/or in continuity with cartilage destructions caused by overlying pannus. By contrast, only two patients had radiographic erosions. The kappa values of interobserver variation with respect to regional presence or absence of bone and cartilage erosions were 0.94 and 0.92, respectively, indicating almost full concordance.     

基于MR图像的软骨特征自动分割方法

图像分割是关节软骨精确检测和评估的首要前提.针对股骨头软骨MR图像提出基于边缘的自动分割技术.利用Hough变换和髋关节的解剖学结构约束提取股骨头中心和图像的目标位置,确定出粗略分割图像的范围,并结合自适应阈值的Canny边缘检测算子确定被分割图像的边界,按照股骨头软骨边界的像素特点对检测结果进行逐一排查,以去除噪声获得精确的软骨内外边缘.提取内侧与外侧边缘之间的图像信息作为最后的分割结果.实验表明,分割方法可以实现对MR图像中髋关节股骨头软骨快速准确的自动分割.     

Fibroblast Growth Factors and Cellular Communication Network Factors: Intimate Interplay by the Founding Members in Cartilage

Fibroblast growth factors (FGFs) constitute a large family of signaling molecules that act in an autocrine/paracrine, endocrine, or intracrine manner, whereas the cellular communication network factors (CCN) family is composed of six members that manipulate extracellular signaling networks. FGFs and CCNs are structurally and functionally distinct, except for the common characteristics as matricellular proteins. Both play significant roles in the development of a variety of tissues and organs, including the skeletal system. In vertebrates, most of the skeletal parts are formed and grow through a process designated endochondral ossification, in which chondrocytes play the central role. The growth plate cartilage is the place where endochondral ossification occurs, and articular cartilage is left to support the locomotive function of joints. Several FGFs, including FGF-2, one of the founding members of this family, and all of the CCNs represented by CCN2, which is required for proper skeletal development, can be found therein. Research over a decade has revealed direct binding of CCN2 to FGFs and FGF receptors (FGFRs), which occasionally affect the biological outcome via FGF signaling. Moreover, a recent study uncovered an integrated regulation of FGF and CCN genes by FGF signaling. In this review, after a brief introduction of these two families, molecular and genetic interactions between CCN and FGF family members in cartilage, and their biological effects, are summarized. The molecular interplay represents the mutual involvement of the other in their molecular functions, leading to collaboration between CCN2 and FGFs during skeletal development.