Publications by authors named "David Hood"

Mitochondria are metabolic hubs that govern skeletal muscle health. While exercise has been established as a powerful inducer of quality control processes that ultimately enhance mitochondrial function, there are currently limited pharmaceutical interventions available that emulate exercise-induced mitochondrial adaptations. To investigate a novel candidate for this role, we examined Sulforaphane (SFN), a naturally occurring compound found in cruciferous vegetables.

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Efficient signal transduction that mediates mitochondrial turnover is a strong determinant of metabolic health in skeletal muscle. Of these pathways, our focus was aimed towards the enhancement of antioxidant capacity, mitophagy, and mitochondrial biogenesis. While physical activity is an excellent inducer of mitochondrial turnover, its ability to ubiquitously activate and enhance mitochondrial turnover prevents definitive differentiation of the contribution made by each pathway.

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Aims: Most type 2 diabetes (T2D) studies have predominantly enrolled White people aged <65 years. This retrospective study evaluated outcomes for iGlarLixi (fixed-ratio combination [FRC] of insulin glargine 100 U/mL and lixisenatide) versus basal-bolus or premixed insulin in African American, Asian and Hispanic adults with T2D aged ≥65 years.

Methods: Medicare claims data were assessed from beneficiaries receiving basal insulin who newly initiated iGlarLixi, basal-bolus insulin, or premixed insulin between 7/1/2019 and 12/30/2021.

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Article Synopsis
  • Skeletal muscle relies on mitochondria for energy and metabolic flexibility, with mitochondrial quality control processes, including the integrated stress response (ISR), playing a crucial role in managing cellular stress.
  • In a study using mice, researchers stimulated muscle contractions and found that ISR was activated after exercise, shown by increased levels of specific proteins and genes associated with stress response, like ATF4 and CHOP.
  • The increase in ATF4 mRNA stability after exercise was linked to the RNA binding protein HuR, suggesting that acute exercise can induce mitochondrial stress and potentially lead to adaptations in muscle over time.
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Dissolved helium atoms evaporate from liquids in super-Maxwellian speed distributions because their interactions are too weak to enforce full thermal equilibration at the surface as they are "squeezed" out of solution. The excess speeds of these He atoms reflect their final interactions with solvent and solute molecules at the surfaces of water and other liquids. We extend this observation by monitoring He atom evaporation from salty water solutions coated with surfactants.

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Background: Muscle atrophy is a common consequence of the loss of innervation and is accompanied by mitochondrial dysfunction. Mitophagy is the adaptive process through which damaged mitochondria are removed via the lysosomes, which are regulated in part by the transcription factor TFE3. The role of lysosomes and TFE3 are poorly understood in muscle atrophy, and the effect of biological sex is widely underreported.

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Atrial fibrillation (AF) is a supraventricular tachyarrhythmia that is strongly associated with cardiovascular (CV) disease and sedentary lifestyles. Despite the benefits of exercise on overall health, AF incidence in high-level endurance athletes rivals that of CV disease patients, suggesting a J-shaped relationship with AF. To investigate the dependence of AF vulnerability on exercise, we varied daily swim durations (120, 180 or 240 min day ) in 7-week-old male CD1 mice.

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Article Synopsis
  • Transcription factor E3 (TFE3) plays a key role in activating genes for mitophagy, helping clear out damaged mitochondria, especially during exercise.
  • A study on wild-type (WT) and TFE3 knockout (KO) mice showed that exercise enhanced muscle endurance and mitochondrial function in WT mice but not in TFE3 KO mice, indicating TFE3 is crucial for these adaptations.
  • Interestingly, the absence of TFE3 did not affect the overall lysosomal content or mitophagy induction during exercise, suggesting TFE3's role extends beyond just mitophagy to overall mitochondrial enhancement.
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Objectives: To investigate the journey to oral anticoagulant (OAC) access following formulary-related rejection of apixaban (Eliquis) and evaluate characteristics associated with failure to achieve OAC access among patients with atrial fibrillation (AF).

Study Design: Retrospective study using the Optum Market Clarity Data from January 2016 through February 2020.

Methods: Patients had at least 1 claim rejection for apixaban due to prior authorization (PA), formulary exclusion (FE), or quantity limit (QL) and at least 1 AF diagnosis on or before the rejected claim.

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Mitochondria control cellular functions through their metabolic role. Recent research that has gained considerable attention is their ability to transfer between cells. This has the potential of improving cellular functions in pathological or energy-deficit conditions, but little is known about the role of mitochondrial transfer in sustaining cellular homeostasis.

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In the broad field of inflammation, skeletal muscle is a tissue that is understudied. Yet it represents about 40% of body mass in non-obese individuals and is therefore of fundamental importance for whole body metabolism and health. This article provides an overview of the unique features of skeletal muscle tissue, as well as its adaptability to exercise.

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Background: Nonadherence to oral anticoagulants (OACs) is a challenge to stroke risk reduction in patients with nonvalvular atrial fibrillation (NVAF). Data on primary medication nonadherence (PMN) in NVAF are lacking.

Objectives: Our aim was to assess the rates and predictors of PMN among NVAF patients who were newly prescribed an OAC.

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Mitochondrial function is widely recognized as a major determinant of health, emphasizing the importance of understanding the mechanisms promoting mitochondrial quality in various tissues. Recently, the mitochondrial unfolded protein response (UPR) has come into focus as a modulator of mitochondrial homeostasis, particularly in stress conditions. In muscle, the necessity for activating transcription factor 4 (ATF4) and its role in regulating mitochondrial quality control (MQC) have yet to be determined.

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Solvated electrons (e) are among nature's most powerful reactants, with over 2600 reactions investigated in bulk water. These electrons can also be created at and near the surface of water by exposing an aqueous microjet in vacuum to gas-phase sodium atoms, which ionize into e and Na within the top few layers. When a reactive surfactant is added to the jet, the surfactant and e become coreactants localized in the interfacial region.

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Altered mitochondrial quality and function in muscle may be involved in age-related physical function decline. The role played by the autophagy-lysosome system, a major component of mitochondrial quality control (MQC), is incompletely understood. This study was undertaken to obtain initial indications on the relationship between autophagy, mitophagy, and lysosomal markers in muscle and measures of physical performance and lower extremity tissue composition in young and older adults.

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Exercise is one of the only nonpharmacological remedies known to counteract genetic and chronic diseases by enhancing health and improving life span. Although the many benefits of regular physical activity have been recognized for some time, the intricate and complex signaling systems triggered at the onset of exercise have only recently begun to be uncovered. Exercising muscles initiate a coordinated, multisystemic, metabolic rewiring, which is communicated to distant organs by various molecular mediators.

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With age, skeletal muscle undergoes a progressive decline in size and quality. Imbalanced mitochondrial turnover and the resultant dysfunction contribute to these phenotypic alterations. Motor neuron denervation (Den) is a contributor to the etiology of muscle atrophy associated with age.

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Objectives: The Mitochondrial Unfolded Protein Response (UPR) is a compartment-specific mitochondrial quality control (MQC) mechanism that uses the transcription factor ATF5 to induce the expression of protective enzymes to restore mitochondrial function. Acute exercise is a stressor that has the potential to temporarily disrupt organellar protein homeostasis, however, the roles of ATF5 and the UPR in maintaining basal mitochondrial content, function and exercise-induced MQC mechanisms in skeletal muscle are not known.

Methods: ATF5 KO and WT mice were examined at rest or after a bout of acute endurance exercise.

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Nitrogen heterocycles are known to be important light-absorbing chromophores in a newly discovered class of aerosols, commonly referred to as "brown carbon" (BrC) aerosols. Due to their significant absorption and spectral overlap with the solar actinic flux, these BrC chromophores steer the physical and optical properties of aerosols. To model the local aqueous solvation environment surrounding BrC chromophores, we generated cold molecular complexes with water and a prototypical BrC chromophore, 1-phenylpyrrole (1PhPy), using supersonic jet-cooling and explored their intermolecular interactions using single-conformation spectroscopy.

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Background: Aging decreases skeletal muscle mass and quality. Maintenance of healthy muscle is regulated by a balance between protein and organellar synthesis and their degradation. The autophagy-lysosome system is responsible for the selective degradation of protein aggregates and organelles, such as mitochondria (i.

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The adaptive plasticity of mitochondria within a skeletal muscle is regulated by signals converging on a myriad of regulatory networks that operate during conditions of increased (i.e., exercise) and decreased (inactivity, disuse) energy requirements.

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Mitochondria are key metabolic and regulatory organelles that determine the energy supply as well as the overall health of the cell. In skeletal muscle, mitochondria exist in a series of complex morphologies, ranging from small oval organelles to a broad, reticulum-like network. Understanding how the mitochondrial reticulum expands and develops in response to diverse stimuli such as alterations in energy demand has long been a topic of research.

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Deficits in skeletal muscle mitochondrial content and quality are observed following denervation-atrophy. This is due to alterations in the biogenesis of new mitochondria as well as their degradation via mitophagy. The regulation of autophagy and mitophagy over the course of denervation (Den) remains unknown.

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The biogenesis of mitochondria requires the coordinated expression of the nuclear and the mitochondrial genomes. However, the vast majority of gene products within the organelle are encoded in the nucleus, synthesized in the cytosol, and imported into mitochondria via the protein import machinery, which permit the entry of proteins to expand the mitochondrial network. Once inside, proteins undergo a maturation and folding process brought about by enzymes comprising the unfolded protein response (UPR).

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