Preventive Vitamin A Supplementation Improves Striatal Function in 6-Hydroxydopamine Hemiparkinsonian Rats.

BACKGROUND: The mechanisms leading to a loss of dopaminergic (DA) neurons from the substantia nigra pars compacta (SNc) in Parkinson's disease (PD) have multifactorial origins. In this context, nutrition is currently investigated as a modifiable environmental factor for the prevention of PD. In particular, initial studies revealed the deleterious consequences of vitamin A signaling failure on dopamine-related motor behaviors. However, the potential of vitamin A supplementation itself to prevent neurodegeneration has not been established yet. OBJECTIVE: The hypothesis tested in this study is that preventive vitamin A supplementation can protect DA neurons in a rat model of PD. METHODS: The impact of a 5-week preventive supplementation with vitamin A (20 IU/g of diet) was measured on motor and neurobiological alterations induced by 6-hydroxydopamine (6-OHDA) unilateral injections in the striatum of rats. Rotarod, step test and cylinder tests were performed up to 3 weeks after the lesion. Post-mortem analyses (retinol and monoamines dosages, western blots, immunofluorescence) were performed to investigate neurobiological processes. RESULTS: Vitamin A supplementation improved voluntary movements in the cylinder test. In 6-OHDA lesioned rats, a marked decrease of dopamine levels in striatum homogenates was measured. Tyrosine hydroxylase labeling in the SNc and in the striatum was significantly decreased by 6-OHDA injection, without effect of vitamin A. By contrast, vitamin A supplementation increased striatal expression of D2 and RXR receptors in the striatum of 6-OHDA lesioned rats. CONCLUSIONS: Vitamin A supplementation partially alleviates motor alterations and improved striatal function, revealing a possible beneficial preventive approach for PD.

Outcomes in patients treated with chimeric antigen receptor T-cell therapy who were admitted to intensive care (CARTTAS): an international, multicentre, observational cohort study.

BACKGROUND: Chimeric antigen receptor (CAR) T-cell therapy can induce side-effects such as cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome (ICANS), which often require intensive care unit admission. The aim of this study was to describe management of critically ill CAR T-cell recipients in intensive care. METHODS: This international, multicentre, observational cohort study was done in 21 intensive care units in France, Spain, the USA, the UK, Russia, Canada, Germany, and Austria. Eligible patients were aged 18 years or older; had received CAR T-cell therapy in the past 30 days; and had been admitted to intensive care for any reason. Investigators retrospectively included patients admitted between Feb 1, 2018, and Feb 1, 2019, and prospectively included patients admitted between March 1, 2019, and Feb 1, 2020. Demographic, clinical, laboratory, treatment, and outcome data were extracted from medical records. The primary endpoint was 90-day mortality. Factors associated with mortality were identified using a Cox proportional hazard model. FINDINGS: 942 patients received CAR T-cell therapy, of whom 258 (27%) required admission to intensive care and 241 (26%) were included in the analysis. Admission to intensive care was needed within median 4·5 days (IQR 2·0-7·0) of CAR T-cell infusion. 90-day mortality was 22·4% (95% CI 17·1-27·7; 54 deaths). At initial evaluation on admission, isolated cytokine release syndrome was identified in 101 patients (42%), cytokine release syndrome and ICANS in 93 (39%), and isolated ICANS in seven (3%) patients. Grade 3-4 cytokine release syndrome within 1 day of admission to intensive care was found in 50 (25%) of 200 patients and grade 3-4 ICANS in 38 (35%) of 108 patients. Bacterial infection developed in 30 (12%) patients. Life-saving treatments were used in 75 (31%) patients within 24 h of admission to intensive care, primarily vasoactive drugs in 65 (27%) patients. Factors independently associated with 90-day mortality by multivariable analysis were frailty (hazard ratio 2·51 [95% CI 1·37-4·57]), bacterial infection (2·12 [1·11-4·08]), and lifesaving therapy within 24 h of admission (1·80 [1·05-3·10]). INTERPRETATION: Critical care management is an integral part of CAR T-cell therapy and should be standardised. Studies to improve infection prevention and treatment in these high-risk patients are warranted. FUNDING: Groupe de Recherche Respiratoire en Réanimation Onco-Hématologique.

Controlled association in suspensions of charged nanoparticles with a weak polyelectrolyte.

The properties of high-pH suspensions of mixtures of silica with low-molecular-weight samples of the water-soluble polymer polyethylenimine (PEI) have been studied. At pH > 10 and low ionic strength, silica nanoparticles are stabilized by a negative surface charge, and PEI has only a very low positive charge. The adsorption of PEI induces a localized positive charge on the segments of polymer closest to the silica surface. The parts of the molecule furthest away from the surface have little charge because of the high pH of the medium. The polymer-covered particle remains negatively charged, imparting some electrostatic stabilization. Suspensions of silica and low-molecular-weight PEI are low-viscosity fluids immediately after mixing, but aggregation occurs leading to the eventual gelation (or sedimentation at lower concentrations) of these mixtures, indicating colloidal instability. The gelation time passes through a minimum with increasing surface coverage. The rate of gelation increases exponentially with molecular weight: for molecular weight > or = 10,000 Da PEI, the instability is so severe that uniform suspensions cannot be produced using simple mixing techniques. The gelation rates increase rapidly with temperature, ionic strength, and reduction in pH. The rate of gelation increases with increasing particle concentration at low surface coverage but decreases at high coverage as a consequence of a small increase in pH. Gels are broken by application of high shear into aggregates that re-gel more rapidly than the original discrete coated particles.