骨钙素减轻糖尿病大鼠血-视网膜屏障的损伤

目的：研究骨钙素（Osteocalcin）对链脲佐菌素诱导的糖尿病大鼠血-视网膜屏障的影响。方法：取健康SD大鼠24只,随机分为正常对照组、糖尿病1月（DM1）组、糖尿病骨钙素干预（DM1＋OCGY）组。尾静脉注射STZ建立DM模型,成模后DM1＋OCGY组腹腔注射骨钙素（2．57mg·kg·1·d^-1）,DMl组腹腔注射等量生理盐水,1个月后处死动物。用伊文思蓝方法检测大鼠血-视网膜屏障的改变。结果：造模1月后大鼠视网膜血管渗透性显著增加,共聚焦显微镜显示红色荧光斑点主要分布在视网膜血管周围,给予骨钙素后,红色荧光斑点明显减少,进一步定量显示1M糖尿病大鼠视网膜伊文思蓝含量为57．4±8．7μg·g^-1,骨钙素能够改变这种变化,DM1＋OCGY组伊文思蓝含量为26．1±3．8μg·g^-1。结论：骨钙素能抑制糖尿病视网膜病的血管渗漏,对糖尿病引起的血一视网膜屏障破坏有保护作用。     

骨钙素减轻糖尿病大鼠血- 视网膜屏障的损伤

目的:研究骨钙素(Osteocalcin)对链脲佐菌素诱导的糖尿病大鼠血-视网膜屏障的影响。方法:取健康SD大鼠24只,随机分为正常对照组、糖尿病1月(DM1)组、糖尿病骨钙素干预(DM1+OCGY)组。尾静脉注射STZ建立DM模型,成模后DM1+OCGY组腹腔注射骨钙素(2.57 mg.kg-.1d-1),DM1组腹腔注射等量生理盐水,1个月后处死动物。用伊文思蓝方法检测大鼠血-视网膜屏障的改变。结果:造模1月后大鼠视网膜血管渗透性显著增加,共聚焦显微镜显示红色荧光斑点主要分布在视网膜血管周围,给予骨钙素后,红色荧光斑点明显减少,进一步定量显示1M糖尿病大鼠视网膜伊文思蓝含量为57.4±8.7μg.g-1,骨钙素能够改变这种变化,DM1+OCGY组伊文思蓝含量为26.1±3.8μg.g-1。结论:骨钙素能抑制糖尿病视网膜病的血管渗漏,对糖尿病引起的血-视网膜屏障破坏有保护作用。     

The Role of Apelin in the Retina of Diabetic Rats

Purpose

Apelin is a novel adipocytokine participating in diabetes, but its role in diabetic retinopathy (DR) is unknown. Our study aimed to investigate the effect of apelin on the proliferative potential in DR along with its antagonist inhibitory effects.

Principal Findings

Strong staining of apelin, co-localized with glial fibrillary acidic protein (GFAP) and vascular endothelial growth factor (VEGF) was observed in the retina of diabetic rats. Apelin, GFAP, and VEGF mRNA and protein levels were significantly increased in the sample’s retinas. Moreover, exogenous apelin promoted retinal Müller cell proliferation in vivo. Simultaneously, apelin induced GFAP and VEGF expression. F13A markedly reduced retinal gliosis caused by diabetes. Furthermore, F13A suppressed both GFAP and VEGF expression in vivo.

Significance

Our results strongly suggest that apelin is associated with the development of DR and contributes to changes in the retinas of diabetic rats. Apelin induced promotion of cell proliferation lends support to the possibility that apelin may play a role in the progression of DR to a proliferative phase. This possible role deserves further investigation, which may offer new perspectives in the early prevention and treatment of DR.     

Reduced Levels of Brain Derived Neurotrophic Factor (BDNF) in the Serum of Diabetic Retinopathy Patients and in the Retina of Diabetic Rats

Diabetic retinopathy (DR) is widely recognized as a neurovascular disease. Retina, being a neuronal tissue of the eye, produces neurotrophic factors for its maintenance. However, diabetes dysregulates their levels and thereby may damage the retina. Among neurotrophins, brain derived neurotrophic factor (BDNF) is the most abundant in the retina. In this study, we investigated the level of BDNF in the serum of patients with DR and also in the serum and retina of streptozotocin-induced diabetic rats. The level of BDNF was significantly decreased in the serum of proliferative diabetic retinopathy patients as compared to that of non-diabetic healthy controls (25.5 ± 8.5–10.0 ± 8.1 ng/ml, p < 0.001) as well as compared to that of diabetic patients with no retinopathy (21.8 ± 4.7–10.0 ± 8.1 ng/ml, p < 0.001), as measured by ELISA techniques. The levels of BDNF in the serum and retina of diabetic rats were also significantly reduced compared to that of non-diabetic controls (p < 0.05). In addition, the expression level of tropomyosin-related kinase B (TrkB) was significantly decreased in diabetic rat retina compared to that of non-diabetic controls as determined by Western blotting technique. Caspase-3 activity was increased in diabetic rat retina after 3 weeks of diabetes and remained elevated until 10 weeks, which negatively correlated with the level of BDNF (r = ?0.544, p = 0.013). Our results indicate that reduced levels of BDNF in diabetes may cause apoptosis and neurodegeneration early in diabetic retina, which may lead to neuro-vascular damage later in DR.     

Potential Role of Endoplasmic Reticulum Stress in Pathogenesis of Diabetic Retinopathy

Diabetes mellitus is a metabolic disease that leads to several complications which include retinopathy. Multiple biochemical abnormalities have been proposed to explain the development of retinopathy, including oxidative stress. Although the existence of oxidative stress has been established in the retina from long standing diabetic animals, pathogenesis and progression of retinopathy remain unclear. In order to gain insight into the pathogenesis of diabetic retinopathy, we analyzed the levels of different oxidative stress biomarkers in the retina at early stages during the progress of streptozotocin-induced diabetes. No significant changes in glutathione content, expression of NADPH-oxidase, levels of lipid peroxidation, nor production of free radicals were observed in the retina up to 45 days of diabetes induction. Likewise, a transient decrease in aconitase activity, parallel to an increase in the superoxide dismutase activity was observed at 20 days of hyperglycemia, suggesting a high capacity of retina to maintain its redox homeostasis, at least at early stages of diabetes. Nonetheless, we found an early and time-dependent increase in the levels of oxidized proteins, which was not affected by the administration of the antioxidant quercetin. Also, positive immunoreactivity to the reticulum stress protein CHOP was found in glial Müller cells of diabetic rat retinas. These findings suggest the occurrence of endoplasmic reticulum stress as a primary event in retina pathogenesis in diabetes.     

细菌脂多糖(LPS)在糖尿病视网膜微血管病变中的作用

本研究旨在通过Akita小鼠糖尿病模型及糖尿病人群血浆样本,探讨病原体相关性分子细菌脂多糖(lipopolysaccharide,LPS)在糖尿病视网膜病变中的重要作用。本研究选择6个月糖尿病病程的Akita小鼠(Ins2+/Akita)及其同年龄组野生型(wild type,WT)小鼠(C57BL/6J)尾静脉内注射脂多糖(LPS)或生理盐水对照共7 d,从影像学、电生理及病理学水平评估糖尿病视网膜眼病进展。最后收集糖尿病视网膜眼病患者及对照人群血标本,通过ELISA测定血浆LPS表达水平。通过光学相干断层扫描技术分析,发现Akita小鼠的视网膜层间厚度较WT小鼠组相比明显变薄(p=0.000 2),LPS处理进一步加重糖尿病小鼠视网膜结构损害(p=0.000 7)。视网膜电图检测发现LPS处理Akita小鼠组的视网膜细胞幅值较生理盐水处理Akita小鼠显著减慢,有统计学意义(p<0.05)。胰酶消化法分离及PAS染色小鼠眼球视网膜微血管网后,计数测得LPS处理显著增加了Akita小鼠视网膜中无细胞毛细血管数量(p=0.002 6),提示LPS在糖尿病微血管损伤中的重要作用。为保证该研究的临床转化性,我们进一步检测了糖尿病视网膜病变患者(n=19)、糖尿病患者(无微血管并发症)(n=23)及健康对照组(n=20)的血浆LPS水平,发现糖尿病患者血浆LPS水平较健康对照组显著升高(p=0.002 3),其中糖尿病视网膜病变患者LPS升高最为显著(p<0.000 1)。本研究表明,循环中细菌脂多糖增加在糖尿病视网膜病变进展中起到重要作用。     

Host-Derived Smooth Muscle Cells Accumulate in Cardiac Allografts: Role of Inflammation and Monocyte Chemoattractant Protein 1

Transplant arteriosclerosis is characterized by inflammation and intimal thickening caused by accumulation of smooth muscle cells (SMCs) both from donor and recipient. We assessed the relationship between clinical factors and the presence of host-derived SMCs in 124 myocardial biopsies from 26 consecutive patients who received hearts from opposite-sex donors. Clinical and demographic information was obtained from the patients'' medical records. Host-derived SMCs accounted for 3.35±2.3% of cells in arterioles (range, 0.08–12.51%). As shown by linear regression analysis, an increased number of SMCs was associated with rejection grade (mean, 1.41±1.03, p = 0.034) and the number of leukocytes (19.1±12.7 per 20 high-power fields, p = 0.01). The accumulation of host-derived SMCs was associated with an increased number of leukocytes in the allografts. In vitro, monocyte chemoattractant protein 1 (MCP-1) released from leukocytes was crucial for SMC migration. After heart allotransplantion, mice treated with MCP-1-specific antibodies had significantly fewer host-derived SMCs in the grafts than mice treated with isotypic antibody controls. We conclude that the number of host-derived SMCs in human cardiac allografts is associated with the rejection grade and that MCP-1 may play pivotal role in recruiting host-derived SMCs into cardiac allografts.     

Role of ACE and PAI-1 Polymorphisms in the Development and Progression of Diabetic Retinopathy

In the present study we determined the association of angiotensin converting enzyme (ACE) and plasminogen activator inhibitor-1 (PAI-1) gene polymorphisms with diabetic retinopathy (DR) and its sub-clinical classes in Pakistani type 2 diabetic patients. A total of 353 diabetic subjects including 160 DR and 193 diabetic non retinopathy (DNR) as well as 198 healthy controls were genotyped by allele specific polymerase chain reaction (PCR) for ACE Insertion/Deletion (ID) polymorphism, rs4646994 in intron 16 and PAI-1 4G/5G (deletion/insertion) polymorphism, rs1799768 in promoter region of the gene. To statistically assess the genotype-phenotype association, multivariate logistic regression analysis was applied to the genotype data of DR, DNR and control individuals as well as the subtypes of DR. The ACE genotype ID was found to be significantly associated with DR (p = 0.009, odds ratio (OR) 1.870 [95% confidence interval (CI) = 1.04–3.36]) and its sub-clinical class non-proliferative DR (NPDR) (p = 0.006, OR 2.250 [95% CI = 1.098–4.620]), while PAI polymorphism did not show any association with DR in the current cohort. In conclusion in Pakistani population the ACE ID polymorphism was observed to be significantly associated with DR and NPDR, but not with the severe form of the disease i.e. proliferative DR (PDR).     

A Key Role for the Endothelium in NOD1 Mediated Vascular Inflammation: Comparison to TLR4 Responses

Understanding the mechanisms by which pathogens induce vascular inflammation and dysfunction may reveal novel therapeutic targets in sepsis and related conditions. The intracellular receptor NOD1 recognises peptidoglycan which features in the cell wall of Gram negative and some Gram positive bacteria. NOD1 engagement generates an inflammatory response via activation of NFκB and MAPK pathways. We have previously shown that stimulation of NOD1 directly activates blood vessels and causes experimental shock in vivo. In this study we have used an ex vivo vessel-organ culture model to characterise the relative contribution of the endothelium in the response of blood vessels to NOD1 agonists. In addition we present the novel finding that NOD1 directly activates human blood vessels. Using human cultured cells we confirm that endothelial cells respond more avidly to NOD1 agonists than vascular smooth muscle cells. Accordingly we have sought to pharmacologically differentiate NOD1 and TLR4 mediated signalling pathways in human endothelial cells, focussing on TAK1, NFκB and p38 MAPK. In addition we profile novel inhibitors of RIP2 and NOD1 itself, which specifically inhibit NOD1 ligand induced inflammatory signalling in the vasculature. This paper is the first to demonstrate activation of whole human artery by NOD1 stimulation and the relative importance of the endothelium in the sensing of NOD1 ligands by vessels. This data supports the potential utility of NOD1 and RIP2 as therapeutic targets in human disease where vascular inflammation is a clinical feature, such as in sepsis and septic shock.     

Prevalence of Diabetic Retinopathy in Mainland China: A Meta-Analysis

Background

Although diabetic retinopathy (DR) is considered to be a major cause of blindness, this is the first meta-analysis to investigate the pooled prevalence of DR in mainland China.

Methodology/Principal Findings

We conducted a search of all English reports on population-based studies for the prevalence of DR using Medline, EMbase, Web of Science, Google (scholar), and all Chinese reports were identified manually and on-line using CBMDisc, Chongqing VIP database, and CNKI database. A meta-analysis was carried out. The fixed effects model or random effects model was used as a statistical test for homogeneity. Nineteen studies were included. The prevalence of DR, non-proliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR) in the pooled general population was 1.3% (95%CI: 0.5%–3.2%), 1.1% (95%CI: 0.6%–2.1%), and 0.1% (95%CI: 0.1%–0.3%), respectively, but was 23% (95%CI: 17.8%–29.2%), 19.1% (95%CI: 13.6%–26.3%), and 2.8% (95%CI: 1.9%–4.2%) in the diabetic group. The prevalence rate of DR in the pooled rural population was higher than that in the urban population, 1.6% (95%CI: 1.3%–2%), and the diabetic population, 29.1% (95%CI: 20.9%–38.9%). The prevalence of DR was higher in the Northern region compared with the Southern region.

Conclusions/Significance

The prevalence of DR in mainland China appeared a little high, and varied according to area. NPDR was more common. This study highlights the necessity for DR screening in the rural areas of China.     

Oxidative Stress,Inflammation, and Diabetic Vasculopathies: The Role of Alpha Tocopherol Therapy

The diabetic state confers an increased propensity to accelerated atherogenesis. In addition to the established risk factors, there is evidence for increased oxidative stress and inflammation in diabetes. Increased oxidative stress is manifested by increased lipid peroxidation (e.g. increased F 2 -isoprostanes) and increased DNA damage. Evidence for increased inflammation includes increased monocyte superoxide and pro-inflammatory cytokine release (IL-1, IL-6, and TNF- &#102 ), increased monocyte adhesion to endothelium and increased levels of plasma C-reactive protein, the prototypic marker of inflammation. Most importantly, alpha tocopherol therapy, especially at high doses, clearly shows a benefit with regards to LDL oxidation, isoprostanes and a decrease in inflammatory markers such as C-reactive protein, pro-inflammatory cytokines and PAI-1 levels. Thus, it appears that, in diabetes, alpha tocopherol therapy could emerge as an additional therapeutic modality.     

Adeno-Associated Virus Mediated Delivery of a Non-Membrane Targeted Human Soluble CD59 Attenuates Some Aspects of Diabetic Retinopathy in Mice

Diabetic retinopathy is the leading cause of visual dysfunction in working adults and is attributed to retinal vascular and neural cell damage. Recent studies have described elevated levels of membrane attack complex (MAC) and reduced levels of membrane associated complement regulators including CD55 and CD59 in the retina of diabetic retinopathy patients as well as in animal models of this disease. We have previously described the development of a soluble membrane-independent form of CD59 (sCD59) that when delivered via a gene therapy approach using an adeno-associated virus vector (AAV2/8-sCD59) to the eyes of mice, can block MAC deposition and choroidal neovascularization. Here, we examine AAV2/8-sCD59 mediated attenuation of MAC deposition and ensuing complement mediated damage to the retina of mice following streptozotocin (STZ) induced diabetes. We observed a 60% reduction in leakage of retinal blood vessels in diabetic eyes pre-injected with AAV2/8-sCD59 relative to negative control virus injected diabetic eyes. AAV2/8-sCD59 injected eyes also exhibited protection from non-perfusion of retinal blood vessels. In addition, a 200% reduction in retinal ganglion cell apoptosis and a 40% reduction in MAC deposition were documented in diabetic eyes pre-injected with AAV2/8-sCD59 relative to diabetic eyes pre-injected with the control virus. This is the first study characterizing a viral gene therapy intervention that targets MAC in a model of diabetic retinopathy. Use of AAV2/8-sCD59 warrants further exploration as a potential therapy for advanced stages of diabetic retinopathy.     

Changes in the Daily Rhythm of Lipid Metabolism in the Diabetic Retina

Disruption of circadian regulation was recently shown to cause diabetes and metabolic disease. We have previously demonstrated that retinal lipid metabolism contributed to the development of diabetic retinopathy. The goal of this study was to determine the effect of diabetes on circadian regulation of clock genes and lipid metabolism genes in the retina and retinal endothelial cells (REC). Diabetes had a pronounced inhibitory effect on the negative clock arm with lower amplitude of the period (per) 1 in the retina; lower amplitude and a phase shift of per2 in the liver; and a loss of cryptochrome (cry) 2 rhythmic pattern in suprachiasmatic nucleus (SCN). The positive clock arm was increased by diabetes with higher amplitude of circadian locomotor output cycles kaput (CLOCK) and brain and muscle aryl-hydrocarbon receptor nuclear translocator-like 1 (bmal1) and phase shift in bmal1 rhythmic oscillations in the retina; and higher bmal1 amplitude in the SCN. Peroxisome proliferator-activated receptor (PPAR) α exhibited rhythmic oscillation in retina and liver; PPARγ had lower amplitude in diabetic liver; sterol regulatory element-binding protein (srebp) 1c had higher amplitude in the retina but lower in the liver in STZ- induced diabetic animals. Both of Elongase (Elovl) 2 and Elovl4 had a rhythmic oscillation pattern in the control retina. Diabetic retinas lost Elovl4 rhythmic oscillation and had lower amplitude of Elovl2 oscillations. In line with the in vivo data, circadian expression levels of CLOCK, bmal1 and srebp1c had higher amplitude in rat REC (rREC) isolated from diabetic rats compared with control rats, while PPARγ and Elovl2 had lower amplitude in diabetic rREC. In conclusion, diabetes causes dysregulation of circadian expression of clock genes and the genes controlling lipid metabolism in the retina with potential implications for the development of diabetic retinopathy.     

The Therapeutic Role of Monocyte Chemoattractant Protein-1 in a Renal Tissue Engineering Strategy for Diabetic Patients

In this study we aim to boost the functional output of the intra-kidney islet transplantation for diabetic patients using a tissue engineered polymeric scaffold. This highly porous electrospun scaffold featured randomly distributed fibers composed of polycaprolactone (PCL) and poliglecaprone (PGC). It successfully sustained murine islets in vitro for up to 4 weeks without detected cytotoxicity. The in vivo study showed that the islet population proliferated by 89% within 12 weeks when they were delivered by the scaffold but only 18% if freely injected. Correspondingly, the islet population delivered by the scaffold unleashed a greater capability to produce insulin that in turn further drove down the blood glucose within 12 weeks after the surgery. Islets delivered by the scaffold most effectively prevented diabetic deterioration of kidney as evidenced by the lack of a kidney or glomerular enlargement and physiological levels of creatinine, urea nitrogen and albumin through week 12 after the surgery. Unlike traditional wisdom in diabetic research, the mechanistic study suggested that monocytes chemoattractant protein-1 (MCP-1) was responsible for the improved preservation of renal functions. This study revealed a therapeutic role of MCP-1 in rescuing kidneys in diabetic patients, which can be integrated into a tissue engineered scaffold to simultaneously preserved renal functions and islet transplantation efficacy. Also, this study affords a simple yet effective solution to improve the clinical output of islet transplantation.     

高压氧治疗糖尿病视网膜病变的研究进展

糖尿病视网膜病变是糖尿病最常见、最主要的微血管并发症之一,具有高发病率,高致盲率的特点,严重影响了人类的生存质量。控制高血糖和改善组织缺氧无疑是防治糖尿病微血管病变的有效方法。如果对糖尿病视网膜病变及时进行治疗,能延缓其发展并能提高病人的生活质量。近年来,随着对糖尿病发病机制的深入研究,很多方法用于防治糖尿病视网膜病人都取得了一定的疗效。而高压氧治疗是许多急慢性疾病的首选治疗方法。已有基础和临床研究证实,高压氧治疗对糖尿病视网膜病变安全有效。因此,作为一种新疗法,高压氧疗法可能会为糖尿病视网膜病变的治疗带来更广泛的应用前景。     

Role of the Liver in Inflammation

INFLAMMATION leads to the appearance in plasma and inflammatory exudates of a protein with anti-inflammatory properties^1–4. The greatest concentration of this anti-inflammatory protein (AIP) occurs relatively late after injury², which suggests that it plays a role in the later stages of the inflammatory reaction and during healing. The synthesis of the protein is shown here to be similar to that of most other plasma proteins in that it occurs in the liver, which raises the question of the extent to which inflammation is influenced or controlled by the rates of synthesis of plasma proteins.     

视网膜微血管内皮细胞在糖尿病视网膜病变中的研究现状

糖尿病视网膜疾病是导致成年人失明的主要因素,是糖尿病的一种令人恐惧的并发症,高血糖被认为是促进其发展的主要原因。高血糖不断地破坏视网膜的微血管系统最终导致视网膜的许多代谢,结构和功能的紊乱。视网膜微血管内皮细胞在微脉管系统中形成树枝状供应视网膜神经,这些内皮细胞的解剖和生理符合重要视觉保护的营养需求[1]。一方面,内皮组织务必确保氧的供应和代谢活跃的视网膜营养供应;另一方面,内皮细胞有助于血-视网膜屏障将循环产生的毒素分子,白细胞促炎性物质排出体外来保护视网膜,这种特性也可能会引起疾病,比如:视网膜血管的渗漏和新生血管,炎性物质转移,因此,视网膜内皮细胞在视网膜缺血性病变,血管炎中起到重要作用,包括糖尿病视网膜病变和视网膜炎症或感染尤其是后葡萄膜炎。使用基因表达和蛋白质组学分析等研究方法,有助于了解这些疾病的发病机制。为了进一步开展对糖尿病视网膜疾病的研究,有必要就目前有关糖尿病视网膜病变患者微血管内皮细胞的研究进展予以综述,旨在为糖尿病视网膜病变的深入研究提供参考依据。