Is dry eye an environmental disease?

Diversos estudos têm demostrado que o contato ocular com poluentes ambientais afeta a composição do filme lacrimal e de estruturas da superfície ocular. Tais efeitos são mediados pela ligação de agentes ambientais com receptores na superfície ocular, levando a ativação de mediadores pró inflamatórios. Esta revisão propõe uma avaliação das evidências publicadas, que associam fatores ambientais as doenças de superfície ocular e ao olho seco. O leitor compreenderá que é possível inferir olho seco ambiental como uma entidade singular dentro do contexto da doença olho seco, diretamente causado pela exposição a poluentes e/ou condições climáticas adversas. Serão descritos os indicadores e achados clínicos, assim como o diagnóstico diferencial das fases aguda e crônica. A avaliação de relatos clínicos e observações epidemiológicas demonstra uma forte associação entre olho seco e fatores ambientais. O conhecimento sobre parâmetros internacionais e ferramentas de monitorização das condições ambientais no mundo, permite identificar localidades e populações mais suceptívies ao olho seco ambiental e pode auxiliar na identificação de indivíduos acometidos e grupos predispostos. E desta forma, melhorar o entendimento e tratamento dessa condição, diminuir os fatores associados, sua frequência e progressão

Ascorbate-induced oxidative stress mediates TRP channel activation and cytotoxicity in human etoposide-sensitive and -resistant retinoblastoma cells

There are indications that pharmacological doses of ascorbate (Asc) used as an adjuvant improve the chemotherapeutic management of cancer. This favorable outcome stems from its cytotoxic effects due to prooxidative mechanisms. Since regulation of intracellular Ca2+ levels contributes to the maintenance of cell viability, we hypothesized that one of the effects of Asc includes disrupting regulation of intracellular Ca2+ homeostasis. Accordingly, we determined if Asc induced intracellular Ca2+ influx through activation of pertussis sensitive Gi/o-coupled GPCR which in turn activated transient receptor potential (TRP) channels in both etoposide-resistant and -sensitive retinoblastoma (WERI-Rb1) tumor cells. Ca2+ imaging, whole-cell patch-clamping, and quantitative real-time PCR (qRT-PCR) were performed in parallel with measurements of RB cell survival using Trypan Blue cell dye exclusion. TRPM7 gene expression levels were similar in both cell lines whereas TRPV1, TRPM2, TRPA1, TRPC5, TRPV4, and TRPM8 gene expression levels were downregulated in the etoposide-resistant WERI-Rb1 cells. In the presence of extracellular Ca2+, 1 mM Asc induced larger intracellular Ca2+ transients in the etoposide-resistant WERI-Rb1 than in their etoposide-sensitive counterpart. With either 100 µM CPZ, 500 µM La3+, 10 mM NAC, or 100 µM 2-APB, these Ca2+ transients were markedly diminished. These inhibitors also had corresponding inhibitory effects on Asc-induced rises in whole-cell currents. Pertussis toxin (PTX) preincubation blocked rises in Ca2+ influx. Microscopic analyses showed that after 4 days of exposure to 1 mM Asc cell viability fell by nearly 100% in both RB cell lines. Taken together, one of the effects underlying oxidative mediated Asc-induced WERI-Rb1 cytotoxicity stems from its promotion of Gi/o coupled GPCR mediated increases in intracellular Ca2+ influx through TRP channels. Therefore, designing drugs targeting TRP channel modulation may be a viable approach to increase the efficacy of chemotherapeutic treatment of RB. Furthermore, Asc may be indicated as a possible supportive agent in anti-cancer therapies

Tissue engineered corneal epithelium derived from clinical-grade human embryonic stem cells

角膜上皮位于角膜最表层，对维持角膜的透明性发挥非常重要的作用。角膜上皮细胞处于不断更新之中，它们更新的源泉在于角膜缘处的上皮干细胞，即角膜缘干细胞。眼表面化学伤、热烧伤以及部分先天性遗传疾病可以引起角膜缘干细胞缺乏，或者使干细胞丧失向正常角膜上皮细胞分化的能力，导致经久不愈的角膜上皮缺损、角膜新生血管、角膜上皮结膜化、角膜溃疡等病理改变，严重影响患者视力，甚至导致失明。由于眼表面的严重破坏，这类患者的治疗具有很大的挑战性，目前比较理想的治疗方法是进行组织工程角膜上皮移植。 厦门大学眼科研究所和中国科学院动物研究所干细胞与生殖生物学国家重点实验室合作研究采用中科院动物研究所研发的我国第一个临床级胚胎干细胞系Q-CTS-hESC-1，体外诱导分化为角膜上皮祖细胞，在此基础上构建组织工程角膜上皮，移植于兔角膜缘干细胞缺乏动物模型，成功重建眼表面。 厦门大学眼科研究所博士研究生贺佳和欧尚坤为该论文的共同第一作者，厦门大学眼科研究所李炜教授、刘祖国教授以及中科院动物所郝捷副研究员为共同通讯作者。【Abstract】Purpose: To construct tissue engineered corneal epithelium from a clinical-grade human embryonic stem cells (hESCs) and investigate the dynamic gene profile and phenotypic transition in the process of differentiation.Methods: A stepwise protocol was applied to induce differentiation of clinical-grade hESCs Q-CTS-hESC-1 and construct tissue engineered corneal epithelium. Single cell RNA sequencing (scRNA-seq) analysis was performed to monitor gene expression and phenotypic changes at different differentiation stages. Immunostaining, realtime quantitative PCR and Western blot analysis were conducted to detect gene and protein expressions. After subcutaneous transplantation into nude mice to test the biosafety, the epithelial construct was transplanted in a rabbit corneal limbal stem cell deficiency (LSCD) model and followed up for eight weeks. Results: The hESCs were successfully induced into epithelial cells. scRNA-seq analysis revealed upregulation of ocular surface epithelial cell lineage related genes such as TP63, Pax6, KRT14, and activation of Wnt, Notch,Hippo, and Hedgehog signaling pathways during the differentiation process. Tissue engineered epithelial cell sheet derived from hESCs showed stratified structure and normal corneal epithelial phenotype with presence of clonogenic progenitor cells. Eight weeks after grafting the cell sheet onto the ocular surface of LSCD rabbit model, a full-thickness continuous corneal epithelium developed to fully cover the damaged areas with normal limbal and corneal epithelial phenotype. Conclusion: The tissue engineered corneal epithelium generated from a clinical-grade hESCs may be feasible in the treatment of limbal stem cell deficiency.This study was supported in part by the National Key R&D Program of China (2018YFA0107301 [to WL], 2018YFA0107304 [to ZL], 2013CB967003 [to WL]), the National Natural Science Foundation of China (NSFC, No.81770894, No.81470602 [to WL], and No.81330022 [to ZL]). 该论文获得了国家重点研发计划项目和国家自然科学基金项目的资助

Gastro-protective effects of isobrucein B, a quassinoid isolated from Picrolemma sprucei

Infusions of Picrolemma sprucei roots, stems and leaves are used in traditional medicine throughout the Amazon region from the Guianas to Brazil and Peru in the treatment of gastritis, intestinal helminths and malaria. As there are no studies describing its mode of action in providing a gastroprotective effect, we determined herein that one of the main constituents found in P. sprucei infusions, the quassinoid isobrucein B (IsoB), reduces some of the pathophysiological effects in a mouse model of non-steroidal anti-inflammatory drug (NSAID)-induced gastritis and provides mechanisms of action. Then, IsoB (1.17 g) was isolated from the roots and stems (6.5 kg) of P. sprucei. Its structure was confirmed by 1D and 2D 1H and 13C NMR, ESI-tof-MS, IR and UV. C57BL/6 strain mice were subcutaneously injected with IsoB (0.5-5 mg kg- 1) or vehicle before oral administration of indomethacin and sacrificed later at different time points. Gastric damage was assessed by measuring lesion length. Leukocyte migration was evaluated based on leukocyte rolling and adhesion using intravital microscopy in the mesenteric microcirculation and tissue MPO activity. Stomach extract cytokine (TNFα, IL-1β and KC/CXCL1) and prostaglandin E2 (PGE2) levels were measured by ELISA and RIA, respectively. IsoB pre-treatment (0.5-5.0 mg kg- 1) significantly reduced the formation of indomethacin-induced stomach lesions in a dose-dependent manner. The decrease in stomach lesions was associated with less observed leukocyte rolling, decreased leukocyte adhesion and less neutrophil infiltration (MPO activity). IsoB (1 mg kg- 1) pre-treatment did not prevent indomethacin-induced decreases in stomach PGE2 levels. However, IL-1β and KC/CXCL1 levels were inhibited by this same IsoB dosage, whereas TNF-α was unchanged. IsoB may be a prototypic compound to provide protective effects against NSAID-induced gastritis and possibly other gastropathies. Moreover, IsoB gastroprotective action may be due to a reduction in IL-1β and KC/CXCL1 production/release and leukocyte rolling, adhesion and migration. © 2014 Elsevier B.V

High-fat diet-induced functional and pathologic changes in lacrimal gland

The lacrimal gland is critical for maintaining the homeostasis of the ocular surface microenvironment through secreting aqueous tears in mammals. Many systemic diseases such as Sjögren syndrome, rheumatoid arthritis, and diabetes can alter the lacrimal gland function, eventually resulting in aqueous tear–deficient dry eye. Here, a high-fat diet (HFD) experimental mouse model was used to clarify how hyperlipidemia affects lacrimal gland function. Aqueous tear secretion fell about 50% after 1 month on a HFD. Lipid droplets accumulated in the matrix and acinar cells of the lacrimal gland after this period, along with changes in the lipid metabolism, changes in gene expression levels, and disruption of fatty acid oxidative activity. Immune cell infiltration and rises in the gene expression levels of the inflammation-related cytokines Il1β, Tnfα, Tsg6, Il10, Mmp2, and Mmp9 were found. HFD also induced mitochondrial hypermegasoma, increased apoptosis, and decreased lacrimal gland acinar cell proliferation. Replacement of the HFD with the standard diet partially reversed pathologic changes in the lacrimal gland. Similarly, supplementing the HFD with fenofibrate also partially reversed the inhibited tear secretion and reduced lipid accumulation, inflammation, and oxidative stress levels. The authors conclude that a HFD induces pathophysiological changes and functional decompensation of the lacrimal gland. Therefore, ingestion of a HFD may be a causative factor of dry eye disease

Correlation coefficients of exams for DED in six, non-overlapping subgroups of patients.

<p>Spearman's correlation coefficient, *p<0.05.</p

Severity grades among study groups.

<p>Frequency (%) of severity scores distribution among the study groups.</p

Values of sensitivity, specificity, positive predictive value and accuracy for the tests of DED among the groups.

<p>Data expressed in % and confidence interval of 95%.</p