Study of alpha‐lipoic acid penetration in the human aqueous after topical administration

Purpose: To determine the concentration of alpha‐lipoic acid in the aqueous and investigate if its topical instillation can increase quantities. Methods: A total of 70 patients selected to undergo cataract surgery were randomly divided into two groups. Group 1 was used as a control group; for the patients in Group 2, a single instillation of alpha‐lipoic acid eye drops (1%) was administered. Immediately before surgery, an aliquot of 40–120 µL of aqueous was aspirated. The individual aspirations were combined to constitute pools representing time intervals with respect to administration. The levels of alpha‐lipoic acid in the aqueous were measured using gas chromatography/mass spectrometry. Results: Pool 0 was created by combining the samples of aqueous obtained from the patients in Group 1, the control group; and the level of alpha‐lipoic acid was 27.5 + 2.6 ng/mL. In the other pools, the time interval between the administration of the eye drops and sampling was, respectively, 23 min, 53 min, 72 min, 93 min and 114 min; and the level of alpha‐lipoic acid was 33.0 + 10.8 ng/mL, 52.0 + 2.5 ng/mL, 86.7 + 2.5 ng/mL, 91.2 + 2.5 ng/mL and 80.3 + 2.5 ng/mL. Conclusion: Our study demonstrates the presence of alpha‐lipoic acid in the aqueous and indicates that its concentration increases after it is administered in the form of eye drops, reaching maximum values after around 93 min. The concentrations that are achieved in the anterior chamber allow us to theorize the possibility of exploiting the antioxidant properties of alpha‐lipoic acid.     

硫辛酸对人晶状体上皮细胞抗紫外线损伤作用的研究

目的探讨硫辛酸在人晶状体上皮细胞（LECs）中抗紫外线损伤的作用。方法对人LECs进行培养和传代,当细胞达80%以上融合时进行不同强度的紫外线照射,照射剂量分别为37、73、112mW/cm2。分别于紫外线照射前、照射中和照射后用0.5mmol/L硫辛酸孵育细胞2h作为实验组,不加硫辛酸的细胞作为对照组。照射后的LECs用常规方法继续培养48h后进行固定,质量分数0.4%龙胆紫染色,自然风干后进行吸光度（A）值测定,计算细胞存活率并进行统计分析。结果正常培养的LECs24h完全贴壁,2～3d时70%以上的LECs达到融合。未用硫辛酸孵育的LECs组细胞连接疏松,细胞膜皱缩,可见部分漂浮细胞。硫辛酸孵育的LECs形态改变程度较轻。不同照射剂量的紫外线照射条件下各硫辛酸培养组LECs存活率差异有统计学意义（Fgroup=23.27,P〈0.01;Fdose=1460.34,P〈0.01）。紫外线照射的不同时间添加硫辛酸各组中LECs的生存率明显高于不添加硫辛酸组（P〈0.05）,而在紫外线照射剂量为半数致死量时其增强细胞存活率的作用最强。在照射剂量为半数致死量及1.5倍半数致死量时其细胞存活率依次为：照射后硫辛酸组〉照射前硫辛酸组〉照射中硫辛酸组〉对照组。结论硫辛酸可以提高紫外线照射后的人LECs的存活率。提示硫辛酸可以减轻紫外线对人LECs的光损害。     

DL-α-硫辛酸对大鼠实验性糖性白内障抑制作用的体外研究

目的本研究观察高浓度葡萄糖对体外培养的大鼠晶状体的损害,以及抗氧化剂DL-α-硫辛酸(LA)的保护作用.方法雄性、7周龄Wistar大鼠,CO2处死后在手术显微镜下,连同囊膜完整摘出晶状体,放入24孔组织培养板中培养.预培养48h过程中,剔除受损伤的晶状体.然后晶状体或者被放入正常浓度(5.56mmol·L-1)葡萄糖培养液中培养,作为对照组,或者被放入高浓度(55.6mmol·L-1)葡萄糖培养液中培养,作为实验组.每组再分成0、0.5、1.0和2.0mmol·L-1 LA亚组,每个亚组含有6个晶状体.用照相方法记录培养过程中大鼠晶状体的形态改变,培养5d后测量晶状体中谷胱甘肽的水平.结果 (1)对照组培养5d晶状体未见明显混浊,其中0.5和1.0mmol·L-1LA都能保持晶状体透明,但在2.0mmol·L-1LA中,从赤道部开始,晶状体表面出现不规则黄色混浊.实验组培养24～48h,晶状体开始膨胀,且在赤道部发生轻微的混浊(白内障);培养5d,晶状体膨胀,皮质内可见片状白色混浊,赤道部出现致密,黄白色环状混浊.在0.5mmol·L-1 LA中,晶状体虽膨胀,但保持透明,在1.0和2.0mmol·L-1 LA中,晶状体膨胀同时,赤道部出现不同程度的环状混浊,其中2.0mmol·L-1LA混浊程度最重;(2)在正常浓度葡萄糖培养液中,晶状体中谷胱甘肽浓度是(1 573±332)μmol·L-1(n=6),0.5,1.0和2.0mmol·L-1 LA添加组中,分别是:(2 531±563)、(2 829±917)、(1 889±805)μmol·L-1(n均=6).在高浓度葡萄糖培养液中,晶状体中谷胱甘肽浓度下降到(813±201)μmol·L-1(n=6),0.5,1.0和2.0μmol·L-1 LA添加组中,分别是(2 096±478)、(2 135±346)、(1 509±748)μmol·L-1 (n均=6).结论高浓度葡萄糖使体外培养的大鼠晶状体膨胀混浊,晶状体中谷胱甘肽水平下降;LA能防止高浓度葡萄糖对体外培养的大鼠晶状体的损害,其中0.5mmol·L-1 LA效果最佳;并且LA能维持晶状体中谷胱甘肽的水平,1.0mmol·L-1 LA效果最佳.     

DL-α-硫辛酸对大鼠实验性糖性自内障抑制作用的体外研究

目的本研究观察高浓度葡萄糖对体外培养的大鼠晶状体的损害,以及抗氧化剂DL-α-硫辛酸(LA)的保护作用.方法雄性、7周龄Wistar大鼠,CO2处死后在手术显微镜下,连同囊膜完整摘出晶状体,放入24孔组织培养板中培养.预培养48h过程中,剔除受损伤的晶状体.然后晶状体或者被放入正常浓度(5.56mmol·L-1)葡萄糖培养液中培养,作为对照组,或者被放入高浓度(55.6mmol·L-1)葡萄糖培养液中培养,作为实验组.每组再分成0、0.5、1.0和2.0mmol·L-1 LA亚组,每个亚组含有6个晶状体.用照相方法记录培养过程中大鼠晶状体的形态改变,培养5d后测量晶状体中谷胱甘肽的水平.结果 (1)对照组培养5d晶状体未见明显混浊,其中0.5和1.0mmol·L-1LA都能保持晶状体透明,但在2.0mmol·L-1LA中,从赤道部开始,晶状体表面出现不规则黄色混浊.实验组培养24～48h,晶状体开始膨胀,且在赤道部发生轻微的混浊(白内障);培养5d,晶状体膨胀,皮质内可见片状白色混浊,赤道部出现致密,黄白色环状混浊.在0.5mmol·L-1 LA中,晶状体虽膨胀,但保持透明,在1.0和2.0mmol·L-1 LA中,晶状体膨胀同时,赤道部出现不同程度的环状混浊,其中2.0mmol·L-1LA混浊程度最重;(2)在正常浓度葡萄糖培养液中,晶状体中谷胱甘肽浓度是(1 573±332)μmol·L-1(n=6),0.5,1.0和2.0mmol·L-1 LA添加组中,分别是(2 531±563)、(2 829±917)、(1 889±805)μmol·L-1(n均=6).在高浓度葡萄糖培养液中,晶状体中谷胱甘肽浓度下降到(813±201)μmol·L-1(n=6),0.5,1.0和2.0μmol·L-1 LA添加组中,分别是(2 096±478)、(2 135±346)、(1 509±748)μmol·L-1 (n均=6).结论高浓度葡萄糖使体外培养的大鼠晶状体膨胀混浊,晶状体中谷胱甘肽水平下降;LA能防止高浓度葡萄糖对体外培养的大鼠晶状体的损害,其中0.5mmol·L-1 LA效果最佳;并且LA能维持晶状体中谷胱甘肽的水平,1.0mmol·L-1 LA效果最佳.     

硫辛酸烟酸二联体对蓝光致大鼠视网膜损伤的防治作用

目的：探讨硫辛酸烟酸二联体(N2L)对蓝光致SD大鼠视网膜损伤的防治作用及最佳药物剂量，探寻其可能存在的保护机制。

方法：选取150-200 g的SPF级雄性SD大鼠36只，随机分为正常对照组、蓝光损伤组、N2L低剂量组(1.0 mg/kg)、N2L中剂量组(2.5 mg/kg)、N2L高剂量组(5.0 mg/kg)及生理盐水组，每组各6只。正常对照组12 h明暗循环饲养，其余组每日接受9 h日常光照，3 h波长455 nm、强度3000±50 lx蓝光照射及12 h黑夜来建立损伤模型，持续14 d。同时每日腹腔注射1 mL对应剂量的药物。14 d后，所有组常规12 h明暗循环再饲养5 d，采用视网膜电图检查。过量麻醉法处死大鼠制备标本，HE染色，在光学显微镜下观察外核层厚度； CheKine^TM超氧化物歧化酶(SOD)活性检测试剂盒检测SOD活性； Western Blot检测大鼠视网膜Caspase-3、醌氧化还原酶1(NQO1)、谷胱甘肽巯基转移酶(GST)、Bcl-2和Bax蛋白表达量。

结果：蓝光损伤组暗视ERG 3.0、10.0(cd·s)/m²刺激光下b波、明视ERG 3.0(cd·s)/m²刺激光下b波振幅及震荡电位第2个波峰振幅显著低于正常对照组(均P<0.01)，N2L中剂量组较蓝光损伤组振幅显著提高(均P<0.05)，且与正常对照组无显著差异； 蓝光损伤组较正常对照组视网膜ONL厚度下降(P<0.001)，N2L中剂量组厚于蓝光损伤组(P<0.001)，与正常对照组无显著差异； N2L中剂量组超氧化物歧化酶活性显著高于其余5组(P<0.05)； 蓝光损伤组Caspase-3、Bax及NQO1表达量较正常对照组更高(均P<0.01)，N2L中剂量组Bax、Caspase-3表达量较蓝光损伤组显著降低(均P<0.001)，而GST、NQO1及Bcl-2显著增加(均P<0.01)。

结论：2.5 mg/kg N2L能有效拮抗蓝光对SD大鼠视网膜的损伤作用，有望成为其防治药物。     

Efficacy of α-Lipoic Acid Against Diabetic Cataract in Rat

Purpose

α-Lipoic acid (LA) is well known as a powerful antioxidant. The efficacy of dihydrolipoate-LA for oral administration against streptozotocin (STZ)-induced diabetic cataract in rat was investigated.

Methods

Rats were divided into three groups, control, diabetes mellitus (DM), and DM treated with LA (DM+LA). Diabetes was induced by intravenous injection of 50?mg/kg STZ. DM+LA rats were fed 30?mg/rat per day LA in their diet. Lens changes were assessed using Scheimpflug images (EAS-1000) and by measuring light-scattering intensity.

Results

Increase in lens light scattering was less (P < 0.05) in DM+LA rats than in DM rats 5 weeks after induction of diabetes. DM rats had the highest and control rats the lowest blood glucose levels at every measurement point up to 111 days (P < 0.05).

Conclusion

LA treatment delayed development and progression of cataract in rats with streptozotocin-induced diabetes.?Jpn J Ophthalmol 2007;51:10–13 © Japanese Ophthalmological Society 2007

     

Alpha lipoic acid changes iron uptake and storage in lens epithelial cells

Alpha lipoic acid (LA) is a cofactor in mitochondrial dehydrogenase complexes. Previous studies have shown that when administered exogenously LA has antioxidant properties, which include free radical scavenging, metal chelation and regeneration of other antioxidants. The cells convert LA into dihydroplipoic acid (DHLA), which in the presence of iron can act as a prooxidant. In vitro DHLA reduces Fe(+3) to Fe(+2) and removes iron from ferritin, increasing the risk of Fe catalyzed free radical formation. In the present study we examined the in vivo effects of lipoic acid treatment on Fe metabolism in cultured lens epithelial cells, and found that LA decreases Fe uptake from transferrin, increases Fe deposition into ferritin and increases the concentration of this protein. When administered together with ascorbic acid, lipoic acid changes the characteristic heavy to light chain ratio of ferritin makeup. The decreased Fe uptake and increased storage diminishes the size of the cytosolic highly reactive Fe pool (LIP). These changes are associated with increased cell resistance to H(2)O(2) challenge. Therefore, LA may reduce the risk of Fe induced oxidative damage and also might be useful as a treatment of Fe overload.     

Homeostasis of the retinal micro-environment: I. Magnesium,potassium and calcium distributions in the avian eye

The concentrations of Mg²⁺, K⁺ and Ca²⁺ in the intraocular fluids (IOFs) and blood plasma of chickens and pigeons were determined by atomic absorption spectrophotometry. The Mg²⁺ concentration in the IOFs of both species was greatest in the liquid vitreous adjacent to the retina followed by aqueous > blood plasma > plasma dialysate. In contrast the concentration of K⁺ in the IOFs of both chickens and pigeons was greater in the aqueous than in the liquid vitreous. The concentrations of Ca²⁺ in all IOF compartments of chicken eyes were virtually identical and were lower than that of blood plasma. The concentrations of Mg²⁺ in the IOFs of the chicken, especially in the liquid vitreous, was remarkably stable; experimentally lowering or raising the plasma Mg²⁺ concentration over a relatively wide range had little or no effect on the Mg²⁺ concentration in the IOFs of these animals. We can conclude that a high Mg²⁺ and low K⁺ concentration in the extracellular fluids of the retina is maintained in the avian eye, as in the mammalian eye, by active transport processes across the blood-retinal barrier systems. Because the avian retina is completely avascular, the site of these homeostatic transport processes must be the epithelium of the retinal choroid and/or the pecten. These findings support the concept that the contribution of the vitreous to the homeostasis of the retinal micro-environment is inversely related in vertebrates to the degree of retinal vascularization.     

Minimal-invasive Therapie der Epiphora durch Ballonkatheterdilatation und Stentimplantation

ZusammenfassungHintergrund Untersuchung der klinischen Effizienz der Ballonkatheterdilatation bzw. Stentimplantation bei Obstruktionen des Tränengangsystems.Methode Bei insgesamt 63 Patienten wurden wegen Epiphora 69 Tränenapparate mittels Ballonkatheterdilatation bzw. Stentimplantation behandelt. In 55 Fällen lag der Symptomatik eine Stenose, in 14 Fällen ein Verschluss des Tränengangsystems zugrunde. In allen Fällen erfolgte präinterventionell die diagnostische Dakryozystographie zur Beurteilung des Stenosegrades und der Lokalisation. Ergebnisse Die Intervention war bei 61 Tränenapparaten technisch erfolgreich. Innerhalb des Nachbeobachtungszeitraumes von maximal 3,5 Jahren betrug die klinische Erfolgsrate bei den Tränenwegsstenosen 83,6%, bei den Verschlüssen 42,9%.Schlussfolgerungen Die Dakryozystoplastie in Form der durchleuchtungskontrollierten Ballondilatation sowie ggf. nachfolgender Stentimplantation stellt im Vergleich zur operativen Therapie ein minimal-invasives Verfahren dar, das bei vergleichbaren technischen und klinischen Erfolgsraten zunehmend als Alternative zur Behandlung der symptomatischen Tränenwegsstenosen und Verschlüsse eingesetzt werden kann.     

Elemental concentrations in ocular tissues of various species

An investigation was undertaken to expand the data base for elemental concentrations within eye tissues of different species. This report provides data on the distribution of calcium, copper, iron and zinc in human, dog, bovine, bird, amphibian and fish ocular tissues. The variation between different eyes of the same individual and different individuals was calculated for each metal. Elemental concentrations between the left and right eyes of an individual were usually closer in value than between two eyes of different individuals.     

Vergleich der Durchmesserreaktion retinaler Arterien und Venen auf Flickerlicht

ZusammenfassungZiel In dieser Studie soll die durch Flickerlicht verursachte Durchmesserreaktion retinaler Arterien und Venen hinsichtlich Ausmaß und zeitlichem Ablauf verglichen werden.Methoden In die klinische Studie wurden 26 gesunde Probanden einbezogen. Der Durchmesser der retinalen Gefäße jeweils eines Auges wurde kontinuierlich mittels eines Retinal vessel analyzer gemessen. Jede Untersuchung bestand aus 100 s Baseline sowie 5 Perioden von 20 s Flickerlichtstimulation, gefolgt von 80 s Beobachtung.Ergebnisse Unmittelbar nach Flickerlicht dilatierten die Arterien um 6,9±2,8% (MW±STD) und die Venen um 6,5±2,8% (Unterschied nicht signifikant). Der Quotient aus arterieller und venöser Dilatation (AVDQ) betrug 1,25±0,69 (Spannweite 0,2 bis 2,8). Es konnte keine signifikante Altersabhängigkeit der arteriellen bzw. venösen Dilatation oder des AVDQ nachgewiesen werden. Die arterielle Dilatation ging nach 25,9±10,8 s in eine leichte Konstriktion von –2,7±1,4% über. Im Gegensatz dazu waren die Venen zum Zeitpunkt des individuellen Konstriktionsmaximums noch um 0,5±1,3% dilatiert (p<0,001).Schlussfolgerungen Die flickerlichtinduzierte Durchmesserreaktion retinaler Arterien und Venen unterscheidet sich bei Gesunden nicht in ihrem mittleren dilatativen Maximum, aber in Form und zeitlichem Verlauf des Abklingens der Dilatation.Unterstützung durch: BMBF 13N7999.Vortrag gehalten auf der 101. Jahrestagung der DOG, Berlin, September 2003.     

Acute Multifocal Placoid Pigment Epitheliopathy Associated with Cavernous Sinus Thrombosis

Acute multifocal placoid pigment epitheliopathy (AMPPE) has been associated with disease of the central nervous system. In this case report, we discuss a patient presenting with AMPPE in the setting of a new central nervous system association: cavernous sinus thrombosis.