Trehalose protects against ocular surface disorders in experimental murine dry eye through suppression of apoptosis

The disaccharide trehalose is a key element involved in anhydrobiosis (the capability of surviving almost complete dehydration) in many organisms. Its presence also confers resistance to desiccation and high osmolarity in bacterial and human cells by protecting proteins and membranes from denaturation. The present study used a novel murine dry eye model induced by controlled low-humidity air velocity to determine whether topically applied trehalose could heal ocular surface epithelial disorders caused by ocular surface desiccation. In addition, the efficacy of 87.6 mM trehalose eyedrops was compared with that of 20% serum, the efficacy of which has been well documented. Mice ocular surface epithelial disorders were induced by exposure of murine eyes to continuous controlled low-humidity air velocity in an intelligently controlled environmental system (ICES) for 21 days, which accelerated the tear evaporation. The mice were then randomized into three groups: the control group received PBS (0.01M) treatment; a second group received 87.6 mM trehalose eyedrops treatment; and the third group received mice serum eyedrops treatment. Each treatment was administered as a 10 μl dose every 6 h for 14 days. The resultant changes in corneal barrier function and histopathologic examination of cornea and conjunctiva were analyzed and the level of apoptosis on the ocular surface was assessed using active caspase-3. After 14 days of treatment, the corneal fluorescein staining area, the ruffling and desquamating cells on the apical corneal epithelium, as well as the apoptotic cells on ocular surface epithelium had significantly reduced in eyes treated with trehalose compared with those treated with serum and PBS. In contrast, after 14 days of treatment, improvements in the thickness of the corneal epithelium, the squamous metaplasia in conjunctival epithelium and the number of goblet cells of the conjunctiva were less marked in eyes treated with trehalose compared with serum. These results demonstrated that trehalose could improve the appearance of ocular surface epithelial disorders due to desiccation through suppression of apoptosis. Trehalose produces some of the same responses as serum upon topical application and can maintain corneal health.     

The Relationship Between Protein Aggregation and Molecular Mobility Below the Glass Transition Temperature of Lyophilized Formulations Containing a Monoclonal Antibody

Purpose. To find out if the physical instability of a lyophilized dosage form is related to molecular mobility below the glass transition temperature. Further, to explore if the stability data generated at temperatures below the glass transition temperature can be used to predict the stability of a lyophilized solid under recommended storage conditions. Methods. The temperature dependence of relaxation time constant, , was obtained for sucrose and trehalose formulations of the monoclonal antibody (5 mg protein/vial) from enthalpy relaxation studies using differential scanning calorimetry. The non-exponentiality parameter, , in the relaxation behavior was also obtained using dielectric relaxation spectroscopy. Results. For both sucrose and trehalose formulations, the variation in with temperature could be fitted Vogel-Tammann-Fulcher (VTF) equation. The two formulations exhibited difference sensitivities to temperature. Sucrose formulation was more fragile and exhibited a stronger non-Arrhenius behavior compared to trehalose formulation below glass transition. Both formulations exhibited <2% aggregation at t values <10, where t is the time of storage. Conclusions. Since the relaxation times for sucrose and trehalose formulations at 5°C are on the order of 10⁸ and 10⁶ hrs, it is likely that both formulations would undergo very little (<2%) aggregation in a practical time scale under refrigerated conditions.     

Evaluation of a new solution containg trehalose for twenty-hour canine lung preservation

We examined the efficacy of two new preservation solutions containing trehalose-an extracellular type (ET-K) of solution and an intracellular type (IT-K) of solution — in relation to that of Euro-Collins (EC) solution in 20-h canine lung preservation. Canine lungs were flushed with one of the three solutions (n=5 for each solution) after pretreatment with PGE₁ (20 g/kg) and were stored for 20 h at 4°C. The left lungs were transplanted and evaluated to 6 h post transplant. In the ET-K group, the arterial oxygen tension after reperfusion was significantly higher than in the IT-K and EC groups. The pulmonary vascular resistance, wet/dry weight ratio, and histological evaluation of each transplanted lung in the ET-K group were also better than in the IT-K and EC groups. This indicates that ET-K solution is useful for 20-h preservation of canine lung grafts.     

海藻糖对低温储存皮肤β-actin的mRNA转录水平及其蛋白表达的影响

目的:观察新型低温保护剂(cryoprotectant,CPA)海藻糖(trehalose)对皮肤骨架蛋白β-肌动蛋白(β-actin)表达及mRNA转录水平的调节作用,以了解在传统低温保护剂中添加海藻糖后是否优于单纯传统低温保护剂的作用。方法:实验将新鲜成人皮肤分为4组,分别经海藻糖-二甲基亚砜(T-D)、二甲基亚砜-丙二醇(D-P)、二甲基亚砜-去血清角质细胞培养液(D-K)、DMEM作为低温保护剂保存,-196℃液氮冻存7 d、14 d复温,设新鲜皮肤为对照组。采用免疫组织化学染色及W estern b lot方法观察β-actin蛋白表达、采用RT-PCR方法对不同低温保护剂保存后皮肤的β-actin基因水平进行深入的研究。结果:T-D组β-actin蛋白表达及基因转录与新鲜组相似(P>0.05),D-P作用其次,其余两组与新鲜组对比均降低明显(P<0.05)。结论:传统低温保护剂中添加海藻糖后对低温储存皮肤β-actin表达的保护作用优于单纯传统低温保护剂。     

The role of trehalose in the global spread of epidemic Clostridium difficile

In a recent study, we reported on two distantly related, epidemic lineages of Clostridium difficile that have acquired independent mechanisms to metabolize low concentrations of trehalose. Here we provide further comment and evidence that a third epidemic lineage common in Asia and Europe, ribotype 017, has evolved this ability.     

Pulmonary TCR γδ T cells induce the early inflammation of granuloma formation by a glycolipid trehalose 6,6′-dimycolate (TDM) isolated from Mycobacterium tuberculosis

We previously showed that formation of pulmonary granulomas in mice in response to a mycobacterial glycolipid, trehalose 6,6′-dimycolate (TDM) is due to the action of TNF-α and not of IFN-γ. However, the mechanisms of formation and maintenance of pulmonary granulomas are not yet clear. The purpose of the present study is to evaluate the mechanisms of granuloma formation by TDM at the early phase. Histological analysis showed that inflammatory cells infiltrated the murine pulmonary interstitium on day 2 after an intravenous injection with TDM as a w/o/w emulsion. Clear granuloma formation was observed on day 7 after the injection. The mRNA expression of IL-17, IFN-γ and macrophage inflammatory protein 2 was found in lung mononuclear cells at the day after TDM injection. The major IL-17-producing cells were T-cell receptor (TCR) γδ T cells expressing Vγ6. In mice depleted of γδ T cells by treatment with anti-TCR γδ monoclonal antibody, the number of TDM-induced granuloma was decreased, but the size of granuloma was not affected. Our results suggest that the mycobacterial glycolipid TDM causes activation of IL-17-producing TCR γδ T cells and stimulates chemotaxis of inflammatory cells including neutrophils in to lung.     

Protective effects of trehalose against Mn‐induced α‐synuclein oligomerization in mice: Involvement of oxidative stress and autophagy

Overexposure to manganese (Mn) is widely known to induce alpha‐synuclein (α‐Syn) oligomerization, which has been attributed to the oxidative damage of α‐Syn protein. Trehalose has been shown to induce autophagy and serve as a chemical chaperone, but little information has been reported about its effect on Mn‐induced α‐Syn oligomerization. In this study, we investigate whether trehalose can effectively interfere with Mn‐induced α‐Syn oligomerization, using different concentrations of trehalose (2% and 4% (g/vol [mL])) in a mouse model of manganism. After 6 weeks of exposure to Mn, both oxidative stress and autophagy were activated and resulted in α‐Syn oligomerization and neuronal cell damage in the mouse brain tissue. Our results also revealed that pretreatment with trehalose significantly reduced the oxidative damage to α‐Syn protein and increased autophagy activation. These findings clearly demonstrated that trehalose can relieve Mn‐induced α‐Syn oligomerization and neuronal cell damage through its anti‐oxidative and autophagy‐inducing effects.     

Synthesis and Evaluation of Trehalose‐Based Compounds as Novel Inhibitors of Cancer Cell Migration and Invasion

As a continuous research for the discovery of trehalose‐based anti‐invasive agents, we developed a convenient synthetic approach for the preparation of 6,6′‐dideoxy‐6,6′‐bis(acylamino)‐α,α‐D‐trehaloses. A series of trehalose‐based amides were prepared through the trityl protection of the two primary hydroxyls of α,α‐D‐trehalose, benzoylation, the removal of the trityl protective group, mesylation, azidation, catalytic hydrogenation in the presence of hydrochloride, coupling reaction with a variety of acids, and subsequent debenzoylation and deacetylation in some cases. Compound 8b , 6,6′‐dideoxy‐6,6′‐bis(2‐hydroxybenzamide)‐ α , α ‐D‐trehalose, was just as potent as the natural brartemicin against the invasion of murine colon 26‐L5 cells. It exhibited no cytotoxicity on human breast adenocarcinoma MDA‐MB‐231 and murine colon 26‐L5 cells. It can significantly inhibit the migration and invasion of the MDA‐MB‐231 cells. The anti‐invasive effect of 8b was possibly related to its inhibitory activity on MMP‐9, its suppression on the expression of MMP‐9 and VEGF, and its deactivation of Akt.     

深冷冻保存对离体牙牙周膜细胞活性影响的研究

目的：探讨应用不同降温方法和不同冷冻保护液的深冷冻保存技术,对人离体牙牙周膜细胞活性的影响。方法：收集新鲜拔除的人第一或第二前磨牙25颗随机分为5组;其中4组使用含海藻糖或不含海藻糖的冷冻保护液,分别应用程序降温或快速降温至－196℃,冷冻保存一周;一组新鲜拔除牙齿为对照组。分别刮取牙根面中1／3的牙周膜组织,消化法收集细胞,台盼蓝染色,高倍镜下计数活细胞数,并计算细胞存活率。结果：不同降温方法不同冷冻保护液深冷冻保存与对照组相比,牙周膜细胞存活率无明显差异。其中,使用含海藻糖的冷冻保护液程序降温的方法牙周膜细胞存活率最高。结论：应用深冷冻技术保存牙齿,牙周膜细胞的活性无明显变化,其中使用含海藻糖的冷冻保护液程序降温的方法对牙周膜细胞的活性影响最小。     

酵母抽提物超滤制备海藻糖工艺条件的优化

利用响应面分析法对影响酵母抽提液中总氮截留率和海藻糖透过率的主要因素进行分析,优化超滤工艺,得到最佳超滤条件:料液质量浓度10 g／dL,料液温度42℃,操作压力0.31MPa,在最佳超滤条件下得到酵母抽提物蛋白质截留率96.5%,海藻糖透过率94.8%,所得RSA图可直观地反映各因素与蛋白氮截留率和海藻糖透过率的关系.