Temperature-sensitive elastin-mimetic dendrimers: Effect of peptide length and dendrimer generation to temperature sensitivity.

Dendrimers are synthetic macromolecules with unique structure, which are a potential scaffold for peptides. Elastin is one of the main components of extracellular matrix and a temperature-sensitive biomacromolecule. Previously, Val-Pro-Gly-Val-Gly peptides have been conjugated to a dendrimer for designing an elastin-mimetic dendrimer. In this study, various elastin-mimetic dendrimers using different length peptides and different dendrimer generations were synthesized to control the temperature dependency. The elastin-mimetic dendrimers formed ß-turn structure by heating, which was similar to the elastin-like peptides. The elastin-mimetic dendrimers exhibited an inverse phase transition, largely depending on the peptide length and slightly depending on the dendrimer generation. The elastin-mimetic dendrimers formed aggregates after the phase transition. The endothermal peak was observed in elastin-mimetic dendrimers with long peptides, but not with short ones. The peptide length and the dendrimer generation are important factors to tune the temperature dependency on the elastin-mimetic dendrimer.

Misalignment of center of foveal avascular zone and center of photoreceptors in eyes with history of retinopathy of prematurity.

To determine the relationship between the center of the foveal avascular zone (FAZ) and the center of the foveal photoreceptors in eyes with a history of retinopathy of prematurity (ROP). To accomplish this, we reviewed the medical records of patients with ROP who were examined at the ROP Clinic of the Tokyo Women's Medical University Hospital. We studied 43 eyes of 23 children with ROP and 67 eyes of 36 control children without any fundus abnormalities. The optical coherence tomography angiographic (OCTA) en face images were used to measure the size and location of the foveal avascular zone (FAZ), and cross-sectional OCT images to measure the central retinal thickness (CRT). Our results showed that the size of the FAZ was significantly smaller in the ROP group (0.200 ± 0.142 mm2) than in the control group (0.319 ± 0.085 mm2; P < 0.01). The CRT was significantly thicker in the ROP group (228 ± 30 µm) than in the control group (189 ± 13 µm; P < 0.01). The mean length of the foveal bulge was not significantly different between the two groups. The actual distance of the misalignment between the center of the FAZ and the center of the photoreceptors was significantly greater in the ROP group (50.4 ± 29.5 µm) than in the control group (39.6 ± 21.9 µm; P = 0.001). The correlations between the actual distance of misalignment and the size of the FAZ, CRT, and length of the foveal bulge in both groups were not significant. Despite the significant misalignment in eyes with a history of ROP, the center of the foveal photoreceptors was consistently located within the narrow FAZ which indicates that the development of the FAZ and photoreceptor formation are interrelated.

Synthesis of temperature-dependent elastin-like peptide-modified dendrimer for drug delivery.

Dendrimers are synthetic macromolecules with a unique structure that are potential unimolecular drug carriers and potential scaffolds for peptides. Elastin is one of the main components of the extracellular matrix, as well as a temperature-sensitive biomacromolecule. Val-Pro-Gly-Val-Gly repeats, an elastin-like peptide, have been used for designing artificial elastin molecules. In this study, we have synthesized a novel type of temperature-dependent drug carrier by conjugating Ac-Val-Pro-Gly-Val-Gly to a dendrimer, named elastin-mimetic dendrimer. The elastin-mimetic dendrimer formed ß-turn structure by heating. The elastin-mimetic dendrimer exhibited the inverse phase transition, depending on pH and NaCl concentration in addition to temperature. The elastin-mimetic dendrimer could encapsulate a model drug, rose bengal, even though the complex stability was similar to the dendrimer without elastin-like peptide. Therefore, the elastin-mimetic dendrimer is a potential drug carrier with temperature- and pH-dependent properties.