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The metabolic demands of neuronal activity are both temporally and spatially dynamic, and neurons are particularly sensitive to disruptions in fuel and oxygen supply. Glucose is considered an obligate fuel for supporting brain metabolism. Although alternative fuels are often available, the extent of their contribution to central carbon metabolism remains debated. Differential fuel metabolism likely depends on cell type, location, and activity state, complicating its study. While biosensors provide excellent spatial and temporal information, they are limited to observations of only a few metabolites. On the other hand, mass spectrometry is rich in chemical information, but traditionally relies on cell culture or homogenized tissue samples. Here, we use mass spectrometry imaging (MALDI-MSI) to focus on the fuel metabolism of the dentate granule cell (DGC) layer in murine hippocampal slices. Using stable isotopes, we explore labeling dynamics at baseline, as well as in response to brief stimulation or fuel competition. We find that at rest, glucose is the predominant fuel metabolized through glycolysis, with little to no measurable contribution from glycerol or fructose. However, lactate/pyruvate, β-hydroxybutyrate (βHB), octanoate, and glutamine can contribute to TCA metabolism to varying degrees. In response to brief depolarization with 50 mM KCl, glucose metabolism was preferentially increased relative to the metabolism of alternative fuels. With an increased supply of alternative fuels, both lactate/pyruvate and βHB can outcompete glucose for TCA cycle entry. While lactate/pyruvate modestly reduced glucose contribution to glycolysis, βHB caused little change in glycolysis. This approach achieves broad metabolite coverage from a spatially defined region of physiological tissue, in which metabolic states are rapidly preserved following experimental manipulation. Using this powerful methodology, we investigated metabolism within the dentate gyrus not only at rest, but also in response to the energetic demand of activation, and in states of fuel competition. [ABSTRACT FROM AUTHOR]

Surgical procedures are often impeded by bleeding and/or leakage of body fluids. These complications cannot always be resolved by conventional surgical techniques. Hemopatch® is a hemostatic patch that also functions as a sealant. Here we document the effectiveness and safety of Hemopatch® for routine procedures of multiple surgical disciplines. To this end, we performed a prospective, multicenter, single-arm, observational registry study. Patients were eligible if they had received Hemopatch® during an open or minimally invasive procedure in one of these specialties: hepatobiliary, cardiovascular, urological, neurological/spinal, general, or lung surgery. Patients were excluded if they had a known hypersensitivity to bovine proteins or brilliant blue, intraoperative pulsatile or severe bleeding and/or infection at the target application site (TAS). The primary endpoint for intraoperative effectiveness was hemostasis assessed as the percentage of patients achieving hemostasis within 2 min and the percentage of patients achieving hemostasis without re-bleeding at the time of surgical closure. The registry enrolled 621 patients at 23 study sites in six European countries. Six hundred twenty patients had completed follow-up information. Hemostasis within 2 min was achieved at 463 (74.5%) of all 621 TASs. Hemostasis without re-bleeding was observed at 620 (99.8%) TASs. Adverse events were reported in 64 patients (10.3%). This Hemopatch® registry shows that Hemopatch® efficiently establishes hemostasis and sealing in a variety of surgical specialties, including minimally invasive procedures. Furthermore, we provide evidence for the safety of Hemopatch® across all the specialties included in the registry. This study is registered at clinicaltrials.gov: NCT03392662. [ABSTRACT FROM AUTHOR]

Secreted protein acidic rich in cysteine (SPARC) is a matricellular protein that modulates the activity of growth factors, cytokines, and extracellular matrix to play multiple roles in tissue development and repair, such as cellular adhesion, migration, and proliferation. Throughout the CNS, SPARC is highly localized in mature ramified microglia, but its role in microglia--in development or during response to disease or injury--is not understood. In the postnatal brain, immature amoeboid myeloid precursors only induce SPARC expression after they cease proliferation and migration, and transform into mature, ramified resting microglia. SPARC null/CX3CR1-GFP reporter mice reveal that SPARC regulates the distribution and branching of mature microglia, with significant differences between cortical gray and white matter in both controls and SPARC nulls. Following ischemic and excitotoxic lesion, reactive, hypertrophic microglia rapidly downregulate and release SPARC at the lesion, concomitant with reactive, hypertrophic perilesion astrocytes upregu-lating SPARC. After photothrombotic stroke in the forelimb sensorimotor cortex, SPARC nulls demonstrate enhanced microgliosis in and around the lesion site, which accompanies significantly enhanced functional recovery by 32 d after lesion. Microglia from SPARC nulls also intrinsically proliferate at a greater rate in vitro--an enhanced effect that can be rescued by the addition of exogenous SPARC. SPARC is thus a novel regulator of microglial proliferation and structure, and, in addition to regulating glioma progression, may play an important role in differently regulating the gray and white matter microglial responses to CNS lesion--and modulating behavioral recovery--after injury. [ABSTRACT FROM AUTHOR]

Neurodevelopmental disorders (NDDs) affect 15% of children and are usually associated with intellectual disability, seizures, and autistic behaviors, among other neurological presentations. Mutations in a wide spectrum of gene families alter key stages of human brain development, leading to defects in neural circuits or brain architecture. Studies in animal systems have provided important insights into the pathobiology of several NDDs. Human stem cell technologies provide a complementary system that allows functional manipulation of human brain cells during developmental stages that would otherwise be inaccessible during human fetal brain development. Therefore, stem cell-based models advance our understanding of human brain development by revealing human-specific mechanisms contributing to the broad pathogenesis of NDDs. We provide a comprehensive overview of the latest research on two and three-dimensional human stem cell-based models. First, we discuss convergent cellular and molecular phenotypes across different NDDs that have been revealed by human iPSC systems. Next, we examine the contribution of in vitro human neural systems to the development of promising therapeutic strategies. Finally, we explore the potential of stem cell systems to draw mechanistic insight for the study of sex dimorphism within NDDs., Competing Interests: Declaration of competing interest The authors declare no financial interests or other interests related to the submitted work., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)