Kuehtreiber, H. | Search bioRxiv

bioRxiv2026

Investigation of sterile hydrogels as topical vehicles for APOSEC™, a stressed peripheral blood mononuclear cell secretome for the treatment of poorly healing wounds

APOSECTM, a complex mixture of secreted proteins, lipids, and extracellular vesicles from stressed peripheral blood monocytes, is currently in clinical trials for the treatment of chronic, poorly healing wounds. When applied to open wounds, 1 mL reconstituted APOSECTM lyophilisate is syringe-mixed with 3 g sterile hydrogel prior to administration. This study investigates the pharmaceutical performance of this novel administration system. A gel formulation (APOgel) was developed for terminal sterilisation in pre-filled syringes with post-sterilisation viscosity ([~]325-350{square}Pa*s at 1{square}s-1) comparable to a commercial benchmark gel. Syringe mixing of APOgel with a liquid APOSECTM surrogate (3:1) reduced viscosity by [~]67% but was highly reproducible across different operators (CV < 6%). Administration of three sequential dose units of the mixture from the syringe revealed an [~]20% higher content of active ingredients in the first and final dispensed compared to the middle unit, indicating non-uniform mixing in the closed syringe system. In vitro release studies over 72{square}h showed a 32% and 48% higher release of a small molecule marker and total proteins from the sterile APOgel compared to the benchmark gel as well as more pronounced gel swelling. However, efficacy studies in a murine wound healing model showed no significant difference between APOgel and the benchmark. These findings indicate that terminal sterilisation of gels for topical applications may provide benefits for more rapid release of active agents but syringe mixing of gels and a liquid requires optimisation to ensure uniform drug distribution. HighlightsO_LIAn autoclavable hydrogel for APOSECTM delivery was developed C_LIO_LIA novel syringe-mixing system for combining a gel with a liquid with subsequent dispensing of different volume units showed non-homogenous active ingredient distribution C_LIO_LIFinal optimised APOSECTM-APOgel formulation maintains functional wound-healing efficacy C_LI

pharmacology and toxicology↗

bioRxiv2023

Single nucleus RNA sequencing reveals glial cell type-specific responses to ischemic stroke

Reactive neuroglia critically shape the brains response to ischemic stroke. However, their phenotypic heterogeneity impedes a holistic understanding of the cellular composition and microenvironment of the early ischemic lesion. Here we generated a single cell resolution transcriptomics dataset of the injured brain during the acute recovery from permanent middle cerebral artery occlusion. This approach unveiled infarction and subtype specific molecular signatures in oligodendrocyte lineage cells and astrocytes, which ranged among the most transcriptionally perturbed cell types in our dataset. Specifically, we characterized and compared infarction restricted proliferating oligodendrocyte precursor cells (OPCs), mature oligodendrocytes and heterogeneous reactive astrocyte populations. Our analyses unveiled unexpected commonalities in the transcriptional response of oligodendrocyte lineage cells and astrocytes to ischemic injury. Moreover, OPCs and reactive astrocytes were involved in a shared immuno-glial cross talk with stroke specific myeloid cells. In situ, osteopontin positive myeloid cells accumulated in close proximity to proliferating OPCs and reactive astrocytes, which expressed the osteopontin receptor CD44, within the perilesional zone specifically. In vitro, osteopontin increased the migratory capacity of OPCs. Collectively, our study highlights molecular cross talk events which might govern the cellular composition and microenvironment of infarcted brain tissue in the early stages of recovery.

neuroscience↗