Hyaluronic Acid Alleviates Oxidative Stress and Apoptosis in Human Tenocytes via Caspase 3 and 7

Rotator cuff tendinopathy (RCT) is the primary reason for shoulder surgery and its clinical management is still challenging. Hyaluronic acid (HA) has been shown to have anti-inflammatory effects in vitro and in vivo under RCT conditions, characterized by an exaggerated oxidative stress (OS). However, molecular mechanisms underlying HA-related effects are still partially disclosed. With these aims, a cell model of RCT was established by exposing primary human tenocytes to H₂O₂ for up to 72 h. Four different HAs by molecular weight were administered to measure nitric oxide (NO) and OS, apoptosis, and collagen 1 expression. In parallel, the well-known antioxidant ascorbic acid was administered for comparison. The present study highlights that HAs characterized by a low molecular weight are able to counteract the H₂O₂-induced OS by decreasing the percentage of apoptotic cells and reversing the activation of caspase 3 and 7. Likewise, NO intracellular levels are comparable to the ones of controls. In parallel, collagen 1 expression was ameliorated by HAs characterized by higher molecular weights compared to AA. These findings confirm that HA plays an antioxidant role comparable to AA depending on the molecular weight, and highlight the molecular mechanisms underlying the HA anti-apoptotic effects.     

透明质酸氧化降解的研究进展

低分子量透明质酸(LMWHA)和透明质酸寡聚糖(o-HA)具有抗氧化、免疫调节、促进伤口愈合、促血管生成和抗肿瘤等生物活性,透明质酸(HA)可以氧化降解为LMWHA和o-HA.对HA的氧化降解进行了综述.     

Hyaluronic Acid Derivative Molecular Weight-Dependent Synthesis and Antimicrobial Effect of Hybrid Silver Nanoparticles

Silver nanoparticles (Ag NPs) appeared as promising antimicrobial candidates to face the development of antibiotic resistance. Although reported as toxic towards mammalian cells, their combination with biomolecules have shown reduced toxicity, while maintaining the antimicrobial function. Herein, hyaluronic acid (HA) with low (40 kDa), medium (200 and 600 kDa) and high (2 MDa) molecular weight (Mw) was modified with adipic acid dihydrazide (ADH) and used as reducing and capping agents to synthesise antimicrobial hybrid Ag NPs. The Mw of the polymer played a crucial role in the morphology, size and antibacterial activity of the Ag NPs. The 600 and 200 kDa HA-ADH-Ag NPs were able to reduce the Escherichia coli and Staphylococcus aureus concentration by more than 3 logs, while the 40 kDa NPs reached ~2 logs reduction. The 2 MDa HA-ADH failed to form homogenous NPs with strong bactericidal activity. A mechanistic study of the interaction with a model bacterial membrane using Langmuir isotherms confirmed the greater interaction between bacteria and higher Mw polymers and the effect of the NP’s morphology. The nanocomposites low toxicity to human skin cells was demonstrated in vitro, showing more than 90% cell viability after incubation with the NPs.     

Change in molecular weight of hyaluronic acid during measurement with a cone-plate rotational viscometer

It was shown using a cone-plate rotational viscometer that the apparent viscosity of a dilute aqueous solution of sodium hyaluronate decreased gradually during the measurement. Hyaluronic acid (HA) forms a characteristic network by entanglements coupling, so two hypotheses could be postulated from the reduction of viscosity due to shearing stress. One was that disentanglement of the temporary network occurred, and the other was that scission of HA chains was responsible. In this study, the reason for the reduction in viscosity was clarified using high-performance gel permeation chromatography with low-angle laser light scattering. It was thus demonstrated that chain scission occurred during the viscometric measurement. On the assumption that the HA degradation was caused by shearing stress, the effects of shearing rate, the initial molecular weight, salt, and polymer concentrations of samples were investigated. High molecular weight HA chains were preferably severed. From the change in polydispersity of the samples it was inferred that due to the viscoelasticity of HA solution scission behavior would differ, depending on the shearing rate. Also, the salt and polymer concentrations were found to exert large influences on the degradation. Thus, it was concluded that the scission rate was related to the expansion of HA molecules in solution. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:2199–2206, 1998     

New Hyaluronic Acid from Plant Origin to Improve Joint Protection—An In Vitro Study

Background: In recent decades, hyaluronic acid (HA) has attracted great attention as a new treatment option for osteoarthritis. Classical therapies are not able to stop the cartilage degeneration process nor do they favor tissue repair. Nowadays, it is accepted that high molecular weight HA can reduce inflammation by promoting tissue regeneration; therefore, the aim of this study was to verify the efficacy of a new high molecular weight HA of plant origin (called GreenIuronic^®) in maintaining joint homeostasis and preventing the harmful processes of osteoarthritis. Methods: The bioavailability of GreenIuronic^® was investigated in a 3D intestinal barrier model that mimics human oral intake while excluding damage to the intestinal barrier. Furthermore, the chemical significance and biological properties of GreenIuronic^® were investigated in conditions that simulate osteoarthritis. Results: Our data demonstrated that GreenIuronic^® crosses the intestinal barrier without side effects as it has a chemical–biological profile, which could be responsible for many specific chondrocyte functions. Furthermore, in the osteoarthritis model, GreenIuronic^® can modulate the molecular mechanism responsible for preventing and restoring the degradation of cartilage. Conclusion: According to our results, this new form of HA appears to be well absorbed and distributed to chondrocytes, preserving their biological activities. Therefore, the oral administration of GreenIuronic^® in humans can be considered a valid strategy to obtain beneficial therapeutic effects during osteoarthritis.     

Use of the MLPA Assay in the Molecular Diagnosis of Gene Copy Number Alterations in Human Genetic Diseases

Multiplex Ligation-dependent Probe Amplification (MLPA) assay is a recently developed technique able to evidence variations in the copy number of several human genes. Due to this ability, MLPA can be used in the molecular diagnosis of several genetic diseases whose pathogenesis is related to the presence of deletions or duplications of specific genes. Moreover, MLPA assay can also be used in the molecular diagnosis of genetic diseases characterized by the presence of abnormal DNA methylation. Due to the large number of genes that can be analyzed by a single technique, MLPA assay represents the gold standard for molecular analysis of all pathologies derived from the presence of gene copy number variation. In this review, the main applications of the MLPA technique for the molecular diagnosis of human diseases are described.     

天然氨基酸作用下丙交酯的开环聚合反应

研究了天然氨基酸作用下丙交酯的开环聚合反应,探讨了氨基酸的酸碱性、浓度、反应条件等对聚合物相对分子质量的影响。结果表明,碱性氨基酸作用下丙交酯的开环聚合可以进行;在D, L-丙交酯的开环聚合反应中,随着氨基酸碱性的增强,聚合物的相对分子质量增大;在反应时间为48 h、反应温度为150 ℃、D,L-丙交酯/L-赖氨酸=50/1（物质的量比,下同）的条件下,可得到重均相对分子质量为12800 g/mol、相对分子质量分布为2.11的聚丙交酯;在D,D-丙交酯和L,L-丙交酯的开环聚合反应中,氨基酸的碱性越强,得到的聚合物的消旋作用越明显。     

Kinetic study of a radical scavenging effect of hyaluronic acid

The rate of the scavenging reaction of hyaluronic acid with hydroxyl radicals was investigated by means of competitive reaction with 4-nitrosodimethylaniline. It was found that the reactivity of hyaluronic acid with hydroxyl radicals depends on both the molecular weight and the concentration of hyaluronic acid. These features were accounted for by the characteristic molecular properties of hyaluronic acid in solution.     

Effects of a Catechol-Functionalized Hyaluronic Acid Patch Combined with Human Adipose-Derived Stem Cells in Diabetic Wound Healing

Introduction: Chronic inflammation and impaired neovascularization play critical roles in delayed wound healing in diabetic patients. To overcome the limitations of current diabetic wound (DBW) management interventions, we investigated the effects of a catechol-functionalized hyaluronic acid (HA-CA) patch combined with adipose-derived mesenchymal stem cells (ADSCs) in DBW mouse models. Methods: Diabetes in mice (C57BL/6, male) was induced by streptozotocin (50 mg/kg, >250 mg/dL). Mice were divided into four groups: control (DBW) group, ADSCs group, HA-CA group, and HA-CA + ADSCs group (n = 10 per group). Fluorescently labeled ADSCs (5 × 10⁵ cells/100 µL) were transplanted into healthy tissues at the wound boundary or deposited at the HA-CA patch at the wound site. The wound area was visually examined. Collagen content, granulation tissue thickness and vascularity, cell apoptosis, and re-epithelialization were assessed. Angiogenesis was evaluated by immunohistochemistry, quantitative real-time polymerase chain reaction, and Western blot. Results: DBW size was significantly smaller in the HA-CA + ADSCs group (8% ± 2%) compared with the control (16% ± 5%, p < 0.01) and ADSCs (24% ± 17%, p < 0.05) groups. In mice treated with HA-CA + ADSCs, the epidermis was regenerated, and skin thickness was restored. CD31 and von Willebrand factor-positive vessels were detected in mice treated with HA-CA + ADSCs. The mRNA and protein levels of VEGF, IGF-1, FGF-2, ANG-1, PIK, and AKT in the HA-CA + ADSCs group were the highest among all groups, although the Spred1 and ERK expression levels remained unchanged. Conclusions: The combination of HA-CA and ADSCs provided synergistic wound healing effects by maximizing paracrine signaling and angiogenesis via the PI3K/AKT pathway. Therefore, ADSC-loaded HA-CA might represent a novel strategy for the treatment of DBW.     

Asp-Glu共聚物分子量的控制及其对阻垢性能的影响

为了增强水处理剂聚天冬氨酸的阻垢性能,对其进行了改性研究.利用微波溶剂法合成了天冬氨酸(Asp)-谷氨酸(Glu)的共聚物(即改性聚天冬氨酸),GPC法测定了共聚物的分子量,考察了反应体系中溶剂种类、反应物原料比、溶剂用量、催化剂的种类与用量、微波功率和辐射时间对共聚物重均分子量的影响,研究了重均分子量对共聚物的阻垢性能的影响.结果表明:该反应体系中,适合溶剂为二甲基甲酰胺,催化剂为磷酸或硫酸,谷氨酸与反应物(Asp与Glu之和)的化学计量数为0 3、催化剂与反应物的化学计量数为0.05、溶剂用量为16 mL、微波功率为720 W、辐射时间为3 min时,所得产物对CaCO3阻垢效果良好;对CaSO4阻垢效果最佳的共聚物分子量范围为800～2000,对CaCO3阻垢效果最佳的分子量为2500～5000;这说明适当控制共聚物分子量能使其满足阻垢要求.     

沉淀聚合法合成聚丙烯酸的研究

聚丙烯酸用作锌锰电池凝胶剂可改善CMC胶凝剂易水解的弊病,使电池性能得到根本性提高。丙烯酸的聚合活性大,是一个强放热反应,特别是纯聚丙烯酸,难以用普通方法得到。以偶氮二异丁腈为引发剂、正己烷为溶剂,用沉淀聚合法制备聚丙烯酸。研究了引发剂用量、相对分子质量调节剂用量、单体浓度等因素对聚合物黏均相对分子质量的影响,合成出黏均相对分子质量在9000~270000之间的聚丙烯酸,且单体转化率在96%以上。扫描电镜显示产物为细腻蓬松的粉末。沉淀聚合法可直接得到粉末状产品,后处理简单,溶剂可回收利用,是一种高效、低成本的聚合方法。     

Transcriptomic Analysis in Human 3D Skin Model Injected with Resorbable Hyaluronic Acid Fillers Reveals Foreign Body Response

Usage of injectable dermal fillers applied for aesthetic purposes has extensively increased over the years. As such, the number of related adverse reactions has increased, including patients showing severe complications such as product migration, topical swelling and inflammatory reactions of the skin. In order to understand the underlying molecular events of these adverse reactions we performed a genome-wide gene expression study on the multi-cell type human Phenion^® Full-Thickness Skin Model exposed to five experimental hyaluronic acid (HA) preparations with increasing cross-linking degree, four commercial fillers from Perfectha^®, and non-resorbable filler Bio-Alcamid^®. In addition, we evaluated whether cross-linking degree or particle size of the HA-based fillers could be associated with the occurrence of adverse effects. In all cases, exposure to different HA fillers resulted in a clearly elevated gene expression of cytokines and chemokines related to acute inflammation as part of the foreign body response. Furthermore, for one experimental filler genes of OXPHOS complexes I-V were significantly down-regulated (adjusted p-value < 0.05), resulting in mitochondrial dysfunction which can be linked to over-expression of pro-inflammatory cytokines TNFα and IL-1β and chemokine CCL2. Our hypothesis that cross-linking degree or particle size of the HA-based fillers is related to the biological responses induced by these fillers could only partially be confirmed for particle size. In conclusion, our innovative approach resulted in gene expression changes from a human 3D skin model exposed to dermal fillers that mechanistically substantiate aforementioned adverse reactions, and thereby adds to the weight of evidence that these fillers may induce inflammatory and fibrotic responses.     

尿素增效剂聚天门冬氨酸的分子量及其分布测定

聚天门冬氨酸是一种用途广泛的新型化工试剂,逐渐被应用于尿素增效剂,它的分子量及其分布对其使用性能有较大影响.通过高温凝胶在线黏度色谱仪(GPCV),可以简化特性黏度的计算,快速得到聚天门冬氨酸的分子量及其分布,分子量的最大偏差在1.02%～4.2%之间,同时给出35℃时,0.1mol/L硝酸钠溶液中聚天门冬氨酸溶液的K值为1.09×10-3dL/g,α为0.40.     

The Beneficial Effect of Rosmarinic Acid on Benzophenone-3-Induced Alterations in Human Skin Fibroblasts

Benzophenone-3 (BP-3) is one of the most widely used chemical sunscreens. The results of many in vitro and in vivo tests confirm its high percutaneous penetration and systemic absorption, which question the safety of its wide use. The aim of our research was to assess the effect of this compound on components of the skin extracellular matrix, and to investigate whether rosmarinic acid (RA) could reduce BP-3-induced changes in human skin fibroblasts. BP-3 used at concentrations of 0.1–100 µM caused a number of unfavorable changes in the level of type I collagen, decorin, sulfated glycosaminoglycans, hyaluronic acid, elastin, and expression or activity of matrix metalloproteinases (MMP-1, MMP-2), elastase and hyaluronidase. Moreover, the intracellular retention of collagen was accompanied by changes in the expression of proteins modifying and controlling the synthesis and secretion of this protein. Most importantly, RA at a concentration of 100 µM significantly reduced or completely abolished the adverse effects of BP-3. Based on these findings, it can be concluded that this polyphenol may provide effective protection against BP-3-induced disturbances in skin cells, which may have important clinical implications.     

低分子量的聚丙烯酸钠的合成研究

以H2O2-NaHSO3为引发剂,在超声波辅助下引发丙烯酸单体聚合,研究了单体浓度、引发剂用量、反应温度等对单体转化率和聚丙烯酸钠分子量的影响。结果表明:控制单体浓度30%、引发剂用量4.0%、反应温度60℃,可制得聚丙烯酸钠的相对分子量在2000～3000之间。     

一步法合成聚乳酸的研究

D,L-乳酸在催化剂作用下,以二苯醚为溶剂,直接聚合得到一定分子量的聚乳酸。讨论了催化剂、反应温度、聚合时间等对聚合反应的影响．通过粘均分子量、红外光谱和核磁共振光谱对聚乳酸进行了表征。     

Zebrafish and Medaka: Important Animal Models for Human Neurodegenerative Diseases

Animal models of human neurodegenerative disease have been investigated for several decades. In recent years, zebrafish (Danio rerio) and medaka (Oryzias latipes) have become popular in pathogenic and therapeutic studies about human neurodegenerative diseases due to their small size, the optical clarity of embryos, their fast development, and their suitability to large-scale therapeutic screening. Following the emergence of a new generation of molecular biological technologies such as reverse and forward genetics, morpholino, transgenesis, and gene knockout, many human neurodegenerative disease models, such as Parkinson’s, Huntington’s, and Alzheimer’s, were constructed in zebrafish and medaka. These studies proved that zebrafish and medaka genes are functionally conserved in relation to their human homologues, so they exhibit similar neurodegenerative phenotypes to human beings. Therefore, fish are a suitable model for the investigation of pathologic mechanisms of neurodegenerative diseases and for the large-scale screening of drugs for potential therapy. In this review, we summarize the studies in modelling human neurodegenerative diseases in zebrafish and medaka in recent years.