Mechanistic investigation of thermosensitive liposome immunogenicity and understanding the drivers for circulation half-life: A polyethylene glycol versus 1,2-dipalmitoyl-sn-glycero-3-phosphodiglycerol study.

Various thermosensitive liposome (TSL) formulations have been described to date and it is currently unclear which are optimal for solid tumor treatment. Sufficient circulation half-life is important and most liposomes obtain this by polyethylene glycol (PEG) surface modification. 1,2-dipalmitoyl-sn-glycero-3-phosphodiglycerol (DPPG2) has been described as a promising alternative which increases TSL circulation half-life and facilitates rapid drug release under mild hyperthermia at 20-30 mol%. The present work describes an investigation of the DPPG2-TSL protein corona, blood cell interactions, complement activation in human plasma/blood and hypersensitivity reactions in rats. Furthermore, accelerated blood clearance (ABC) was investigated to obtain a complete assessment of DPPG2-TSL interactions with components of the blood and identify drivers for circulation half-life. A higher mol% DPPG2 increased Apolipoprotein E (ApoE) adsorption and decreased complement activation and granulocyte interaction in vitro. In contrast to PEG-TSL, DPPG2-TSL showed no ABC effect. In vivo hypersensitivity assessment by eicosanoid measurements, platelet and lymphocyte counting resembled the results of in vitro complement activation assays although here all DPPG2-TSL formulations induced hypersensitive responses upon i.v. administration. Prolonged circulation half-life of DPPG2-TSL may be ApoE-induced and the absent ABC effect demonstrates an advantage over PEG-TSL. Low complement activation in human plasma and blood for 20-30 mol% DPPG2-TSL presents a unique formulation attribute with the potential to strengthen clinical evaluation.

Short-Chain Fatty Acids Improve Poststroke Recovery via Immunological Mechanisms.

Recovery after stroke is a multicellular process encompassing neurons, resident immune cells, and brain-invading cells. Stroke alters the gut microbiome, which in turn has considerable impact on stroke outcome. However, the mechanisms underlying gut-brain interaction and implications for long-term recovery are largely elusive. Here, we tested the hypothesis that short-chain fatty acids (SCFAs), key bioactive microbial metabolites, are the missing link along the gut-brain axis and might be able to modulate recovery after experimental stroke. SCFA supplementation in the drinking water of male mice significantly improved recovery of affected limb motor function. Using in vivo wide-field calcium imaging, we observed that SCFAs induced altered contralesional cortex connectivity. This was associated with SCFA-dependent changes in spine and synapse densities. RNA sequencing of the forebrain cortex indicated a potential involvement of microglial cells in contributing to the structural and functional remodeling. Further analyses confirmed a substantial impact of SCFAs on microglial activation, which depended on the recruitment of T cells to the infarcted brain. Our findings identified that microbiota-derived SCFAs modulate poststroke recovery via effects on systemic and brain resident immune cells.SIGNIFICANCE STATEMENT Previous studies have shown a bidirectional communication along the gut-brain axis after stroke. Stroke alters the gut microbiota composition, and in turn, microbiota dysbiosis has a substantial impact on stroke outcome by modulating the immune response. However, until now, the mediators derived from the gut microbiome affecting the gut-immune-brain axis and the molecular mechanisms involved in this process were unknown. Here, we demonstrate that short-chain fatty acids, fermentation products of the gut microbiome, are potent and proregenerative modulators of poststroke neuronal plasticity at various structural levels. We identified that this effect was mediated via circulating lymphocytes on microglial activation. These results identify short-chain fatty acids as a missing link along the gut-brain axis and as a potential therapeutic to improve recovery after stroke.

A modified low-protein infant formula supports adequate growth in healthy, term infants: a randomized, double-blind, equivalence trial.

BACKGROUND: A high protein intake in early life is associated with a risk of obesity later in life. The essential amino acid requirements of formula-fed infants have been reassessed recently, enabling a reduction in total protein content and thus in protein intake. OBJECTIVES: We aimed to assess the safety of an infant formula with a modified amino acid profile and a modified low-protein (mLP) content in healthy term-born infants. Outcomes were compared with a specifically designed control (CTRL) infant formula. METHODS: In this double-blind, randomized controlled equivalence trial, infants received either mLP (1.7 g protein/100 kcal; n = 90) or CTRL formula (2.1 g protein/100 kcal; n = 88) from enrollment (age ≤ 45 d) to 6 mo of age. A breastfed group served as a reference (n = 67). Anthropometry and body composition were determined at baseline, 17 wk (including safety blood parameters), and 6 mo of age. The primary outcome was daily weight gain from enrollment up until the age of 17 wk (at an equivalence margin of ±3.0 g/d). RESULTS: Weight gain from baseline (mean ± SD age: 31 ± 9 d) up to the age of 17 wk was equivalent between the mLP and CTRL formula groups (27.9 and 28.8 g/d, respectively; difference: -0.86 g/d; 90% CI: -2.36, 0.63 g/d). No differences in other growth parameters, body composition, or in adverse events were observed. Urea was significantly lower in the mLP formula group than in the CTRL formula group (-0.74 mmol/L; 95% CI: -0.97, -0.51 mmol/L; P < 0.001). Growth rates, fat mass, fat-free mass, and several essential amino acids were significantly higher in both formula groups than in the breastfed reference group. CONCLUSIONS: Feeding an infant formula with a modified amino acid profile and a lower protein content from an average age of 1 mo until the age of 6 mo is safe and supports an adequate growth, similar to that of infants consuming CTRL formula. This trial was registered at www.trialregister.nl as Trial NL4677.

Serum concentrations of TNF-α and its soluble receptors during psychotherapy in German soldiers suffering from combat-related PTSD.

BACKGROUND: Changes in serum concentrations of tumor necrosis factor-α (TNF-α) and its soluble receptors (sTNF-R) p55 and p75 have been shown to be associated with various psychiatric treatments. SUBJECTS AND METHODS: Before and after treatment, serum levels of TNF-α, sTNF-R p55 and sTNF-R p75 were measured in 38 German soldiers who had been deployed abroad and suffered from combat-related post-traumatic stress disorder (PTSD). Patients were randomized either to inpatient psychotherapy (N=21) including eye movement desensitization and reprocessing (EMDR) or to outpatient clinical management (N=17). Symptoms of PTSD were measured using the Post-traumatic Stress Diagnostic Scale (PDS). RESULTS: The PDS score significantly decreased across time in both groups. Serum concentrations of TNF-α increased, while sTNF-R p55 and sTNF-R p75 levels decreased significantly. After the treatment period, we could not detect any significant difference regarding TNF-α, sTNF-R p55 or sTNF-R p75 levels between the inpatient psychotherapy group and the outpatient clinical management control group. CONCLUSIONS: This relatively small clinical study suggests that specific inpatient psychotherapy but also non-specific supportive outpatient treatment for PTSD are associated with changes in the TNF-α system. This may represent an immunological effects or side effects of psychotherapy.