Phase-separating peptides for direct cytosolic delivery and redox-activated release of macromolecular therapeutics.

Biomacromolecules are highly promising therapeutic modalities to treat various diseases. However, they suffer from poor cellular membrane permeability, limiting their access to intracellular targets. Strategies to overcome this challenge often employ nanoscale carriers that can get trapped in endosomal compartments. Here we report conjugated peptides that form pH- and redox-responsive coacervate microdroplets by liquid-liquid phase separation that readily cross the cell membrane. A wide range of macromolecules can be quickly recruited within the microdroplets, including small peptides, enzymes as large as 430 kDa and messenger RNAs (mRNAs). The therapeutic-loaded coacervates bypass classical endocytic pathways to enter the cytosol, where they undergo glutathione-mediated release of payload, the bioactivity of which is retained in the cell, while mRNAs exhibit a high transfection efficiency. These peptide coacervates represent a promising platform for the intracellular delivery of a large palette of macromolecular therapeutics that have potential for treating various pathologies (for example, cancers and metabolic diseases) or as carriers for mRNA-based vaccines.

Decreased postoperative C-reactive protein production in dogs with pyometra through the use of low-dose ketamine.

OBJECTIVE: To determine the effects of subanesthetic ketamine in dogs with pyometra on C-reactive protein (CRP) concentrations following surgery. DESIGN: Prospective, nonconcealed, alternating allocation controlled trial. SETTING: Veterinary teaching hospital. ANIMALS: Sixteen dogs diagnosed with pyometra. INTERVENTIONS: The tentative diagnosis of canine pyometra was based on compatible history, physical examination findings, ultrasonographic findings, and hematological evaluation. Two different anesthesia and analgesic protocols with and without low-dose ketamine were used during and following ovariohysterectomy in 16 female dogs (n = 8 per group) that were diagnosed with naturally occurring pyometra. Dogs were sequentially allocated to treatment groups in an alternating fashion without concealment. Serum was collected before, 24, and 48 hours after surgery for CRP measurement. MEASUREMENTS AND MAIN RESULTS: Perioperative physical parameters in the 2 groups of dogs were similar. The serum concentrations of CRP in both groups were essentially the same before surgery, but significantly increased in the control group and decreased in ketamine group at 48 hours after surgery. CONCLUSIONS: Low-dose ketamine attenuated the postoperative concentration of serum CRP in dogs with pyometra compared with dogs that did not receive ketamine in the perioperative period. Further studies are warranted to determine the clinical implications of these findings.