Patterns of anti-vascular endothelial growth factor treatment for chorioretinal vascular diseases: Analysis of a nationwide claims database in Japan.

BACKGROUND: Although intravitreal anti-vascular endothelial growth factor therapy is currently considered the first-line treatment for chorioretinal vascular diseases in Japan, information regarding its treatment pattern is scarce. This study investigated the patterns of anti-vascular endothelial growth factor treatment for chorioretinal vascular diseases. METHODS: A health insurance claims database from acute care hospitals was used to estimate treatment intervals and continuation and drop-out rates regarding the anti-vascular endothelial growth factor. Patients aged ≥50 years diagnosed with neovascular age-related macular degeneration or aged ≥18 years diagnosed with diabetic macular edema or retinal vein occlusion were analyzed. RESULTS: Data were included for 76,535, 49,704, and 37,681 patients with neovascular age-related macular degeneration, diabetic macular edema, and retinal vein occlusion, respectively; exactly 8,111, 2,283, and 6,896 received the treatment, respectively. The mean and median interval ranges during the maintenance phase by treatment initiation year were 94-100 and 73-80, 111-120 and 98-102, and 97-103 and 87-93 days for neovascular age-related macular degeneration, diabetic macular edema, and retinal vein occlusion, respectively, without any trend over time. A tendency to increase the treatment continuation rate was indicated in later years by Kaplan-Meier curves. The drop-out rate in the treatment initiation year (2016) was 32% from 63% (2009), 53% from 69% (2014), and 36% from 47% (2013) for neovascular age-related macular degeneration, diabetic macular edema, and retinal vein occlusion, respectively. CONCLUSIONS: For all these diseases, the treatment intervals did not change remarkably, and a tendency toward improved treatment continuation was suggested.

Insights into the mode of action of 1,2,6,7-tetraoxaspiro [7.11] nonadecane (N-89) against adult Schistosoma mansoni worms.

Control of morbidity associated with schistosomiasis via chemotherapy largely relies on the drug praziquantel. Repeated therapy with praziquantel has created concerns about the possible selection of resistant worms and necessitated the search for novel drugs to treat schistosomiasis. Here, a murine model was infected with Schistosoma mansoni and treated with oral 1,2,6,7-tetraoxaspiro [7.11] nonadecane (N-89), which caused a significant reduction in fecundity and egg burden and reduced morbidity when administered at 5-weeks post-infection. The analysis showed that the mode of action occurred through the ingestion of activated N-89 by the worms, and that there was no direct external effect on the S. mansoni worms. Ultrastructural analysis of the treated worms showed disruptions in the gut lumen and the presence of large volumes of material, suggestive of undigested blood meals or red blood cells. In addition, there were reduced vitelline cells in female worms and damage to sub-tegmental musculature in male worms. Eggs recovered from the treated mice showed both damage to the eggs and the production of immature eggs. Expression of mRNA responsible for gut and digestive function and egg production was also significantly affected by N-89 treatment, whereas control genes for musculature showed no significant changes. Thus, N-89 drastically affected the total digestive function and egg production of S. mansoni worms. Physiological processes requiring heme uptake such as egg production and eggshell formation were subsequently affected, suggesting that the compound could be a possible therapeutic drug candidate for schistosomiasis control.

Novel synthetic compounds with endoperoxide structure damage juvenile stage of Schistosoma mansoni by targeting lysosome-like organelles.

The new synthetic compound 1,2,6,7-tetraoxaspiro[7.11]nonadecan (N-89), a novel anti-malaria drug candidate, is also a promising drug candidate against schistosomiasis with killing effects against juvenile stage of S. mansoni. In order to investigate how N-89 kills schistosomes, we used a derivative of N-89, 6-(1,2,6,7-tetraoxaspiro[7.11] nonadec-4-yl)hexan-1-ol (N-251), which enables us to conjugate with fluorescent reagents. Firstly, N-251 showed strong killing effects to larvae of S. mansoni in vitro. Ultrastructural analysis showed the disruptions of the lysosome-like organelles or the acetabular glands, followed by cytoplasmic lysis inside the worm body in N-251-treated group under electron microscopy. For rhodamine-conjugated N-251 and organelle markers, we observed that N-251 accumulated in acidic organelle. In addition, LysoTracker signals in these acidic organelles disappeared in N-251-treated group over time. Finally, we observed that the activity of cathepsin B, a lysosome-specific enzyme, was also decreased together with alternation of acidic organelle marker signal by N-251-treated group. These results suggested that our synthesized compounds induced the dysfunction or the disruption of acidic lysosome-like organelles and finally led to worm death.