The impact of glucosamine on age-related macular degeneration in patients: A nationwide, population-based cohort study.

PURPOSE: To analyze the association between glucosamine (GlcN) use and the risk of age-related macular degeneration (AMD) using claims data from the National Health Insurance Research Database (NHIRD). METHODS: A retrospective, population-based study was conducted with NHIRD data from a 14-year period (2000-2013). Chi-squared and Student's t-tests were used to evaluate differences between the study and comparison cohorts for categorical and continuous variables, respectively. Risk factors for disease development were examined by the adjusted hazard ratio (aHR) with 95% confidence interval. Kaplan-Meier analysis was performed to compare the cumulative risk of AMD between the two cohorts. RESULTS: In total, 1,344 patients with GlcN treatment were enrolled in the study cohort and 5,376 patients without GlcN use were enrolled in the comparison cohort. The incidence rate of AMD was lower with GlcN use (3.65%) than without GlcN use (5.26%) (P = 0.014). GlcN use was associated with a lower risk of developing AMD among patients with hyperlipidemia, coronary artery disease, chronic obstructive pulmonary disease, stroke, other neurological disorders, or degenerative arthritis. Although the incidence of wet type AMD did not significantly differ (P = 0.91), the incidence of dry type AMD was lower in patients with GlcN use (2.9%) than those without GlcN use (4.84%) (P = 0.003). Kaplan-Meier analysis similarly revealed a lower rate of dry type AMD in patients with GlcN use compared to those without GlcN use (log-rank P = 0.004). CONCLUSIONS: GlcN treatment can decrease the risk of developing dry type AMD. Further prospective controlled studies are needed to determine the effectiveness of GlcN treatment in patients with AMD and the associated mechanism.

Evaluation of the relationship between central serous chorioretinopathy and liver cirrhosis: A nationwide, population-based study.

BACKGROUND: Central serous chorioretinopathy (CSCR) and liver cirrhosis share numerous risk factors and may have possible connections. We aimed to investigate whether patients with liver cirrhosis and the severity of cirrhosis have an increased incidence of CSCR. METHODS: This population-based retrospective cohort study was conducted by collecting data from the Taiwan National Health Insurance Research Database from January 1, 2000, to December 31, 2015. We included patients who were newly diagnosed with cirrhosis and selected an equal number of sex- and age-matched control subjects. The effect of cirrhosis on the risk of CSCR was examined via a Cox proportional hazard regression analysis. The cumulative incidence of CSCR was assessed with the Kaplan-Meier method and the log-rank test. RESULTS: Both groups in this study comprised a total of 25 925 individuals. The cirrhotic patients had a significantly higher cumulative risk of developing CSCR in following years than patients without cirrhosis (log-rank test < 0.001). Furthermore, compared with noncirrhotic patients, the risk of CSCR was increased 3.59-fold (95% confidence interval [CI], 2.31-5.28) in cirrhotic patients with complications, and 2.34-fold (95% CI, 1.27-3.24) in cirrhotic patients without complications. Additionally, male sex, springtime, diabetes mellitus, hepatitis B virus, and hepatitis C virus statistical significantly increased the incidence of CSCR. CONCLUSION: Cirrhosis is an independent indicator of CSCR. Among the cirrhotic population, patients with ascites and other complications have a higher incidence of CSCR than those with uncomplicated cirrhosis. Physicians should be observant when managing cirrhotic patients with visual disturbances.

Glucosamine-Induced Autophagy through AMPK⁻mTOR Pathway Attenuates Lipofuscin-Like Autofluorescence in Human Retinal Pigment Epithelial Cells In Vitro.

Age-related macular degeneration (AMD) is a vision-threatening age-associated disease. The retinal pigment epithelial (RPE) cells phagocytose and digest photoreceptor outer segment (POS). Incomplete digestion of POS leads to lipofuscin accumulation, which contributes to the pathology of the AMD. Autophagy could help reduce the amount of lipofuscin accumulation. In the present study, we evaluated the effects of glucosamine (GlcN), a natural supplement, on the induction of autophagy and POS-derived lipofuscin-like autofluorescence (LLAF) in ARPE-19 cells in vitro, and investigated the potential molecular pathway involved. Our results revealed that GlcN had no effect on phagocytosis of POS at the lower doses. GlcN treatment induced autophagy in cells. GlcN decreased the LLAF in native POS-treated cells, whereas malondialdehyde or 4-hydroxynonenal-modified POS attenuated this effect. 3-Methyladenine inhibited GlcN-induced autophagy and attenuated the effect of GlcN on the decrease of the native POS-derived LLAF. Furthermore, GlcN induced the phosphorylation of AMP-activated protein kinase (AMPK) and inhibited the phosphorylation of mammalian target of rapamycin (mTOR), whereas Compound C inhibited these effects of GlcN. Altogether, these results suggest that GlcN decreased the native POS-derived LLAF through induction of autophagy, at least in part, by the AMPK⁻mTOR pathway. This mechanism has potential for the preventive treatment of lipofuscin-related retinal degeneration such as AMD.

Silibinin treatment prevents endotoxin-induced uveitis in rats in vivo and in vitro.

Uveitis, an intraocular inflammatory disease, occurs mostly in young people and can result in the loss of socioeconomic capabilities. Silibinin has been shown to exert anti-inflammatory effects in human retinal pigment epithelial (RPE) cells. The present study investigated the anti-inflammatory effect of silibinin pretreatment on endotoxin-induced uveitis (EIU) in rats and the mechanisms by which it exerts these effects. Uveitis was induced via injection of lipopolysaccharides (LPS) into Lewis rats. Twenty-four hours after the LPS injection, histological examination showed that silibinin decreased inflammatory cell infiltration in the anterior segment of the eyes of LPS-treated rats. Analyses of the aqueous humor showed that silibinin decreased cell infiltration, protein concentration, nitric oxide (NO), and prostaglandin (PG)-E2 production. Western blot analysis indicated that silibinin decreased the expression of inducible NO synthase (iNOS), cyclooxygenase (COX-2), and phosphorylated IkB in the iris-ciliary body (ICB). Immunohistochemistry showed that silibinin decreased intercellular adhesion molecule (ICAM-1) expression in the ICB. In addition, western blot analysis showed that silibinin attenuated the expression of iNOS, COX-2, ICAM-1, and nuclear p65 in LPS-treated RAW cells. In conclusion, silibinin pretreatment prevents EIU and the subsequent production of proinflammatory mediators and ICAM-1, at least in part, by blocking the NF-κB-dependent signaling pathway both in vivo and in vitro. These effects may contribute to the silibinin-mediated preventive effects on intraocular inflammatory diseases such as acute uveitis.

Inhibitory effects of glucosamine on endotoxin-induced uveitis in Lewis rats.

PURPOSE: Glucosamine sulfate (GS) is a naturally occurring sugar that exerts immunosuppressive effects in vitro and in vivo. The authors investigated whether GS modulates the inflammatory reaction in endotoxin-induced uveitis (EIU) of rats and the mechanisms by which it exerts its effects. METHODS: Two-hundred micrograms of lipopolysaccharide (LPS) was injected subcutaneously into Lewis rats to induce EIU. Doses of GS (10, 100, or 1000 mg/kg) were divided into three aliquots and administered intraperitoneally 30 minutes before LPS injection, concurrently with LPS injection, and 30 minutes after LPS injection. Twenty-four hours after LPS injection, aqueous humor was collected for cell counting and measurement of protein concentration. Immunohistochemical staining of the iris-ciliary body was performed to evaluate the effects of GS on intercellular adhesion molecule (ICAM)-1 and nuclear factor (NF)-kappaB activation and to demonstrate macrophage infiltration. The effects of various doses of GS pretreatment were also examined using a mouse macrophage cell line (RAW264.7 cells) and LPS stimulation. Levels of prostaglandin (PG)-E2 and nitric oxide (NO) were determined. Expression of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 were measured using Western blot analysis. The effect of GS on LPS-induced NF-kappaB activation in RAW cells was also examined. RESULTS: Cell counting and analysis of protein concentration in aqueous humor revealed that GS suppressed EIU in rats treated with a high dose of GS (1000 mg/kg). Immunohistochemistry showed that treatment with GS reduced ICAM-1 expression and suppressed activation of NF-kappaB in the iris-ciliary body. The main inflammatory cells in the iris-ciliary body during EIU were macrophages. In LPS-stimulated macrophage RAW cell culture, GS inhibited the production of NO and PG-E2, the expression of iNOS and COX-2, and the activation of NF-kappaB. CONCLUSIONS: GS suppresses EIU in rats by blockading the NF-kappaB-dependent signaling pathway and the subsequent production of ICAM-1 and proinflammatory mediators. This study has extended the authors' previous observation that GS is a potentially important compound for reducing ICAM-1-mediated inflammatory effects in the eye.