Faculty Opinions recommendation of The cellular mechanisms of neuronal swelling underlying cytotoxic edema.

AbstractAn acute reduction in plasma osmolality causes rapid uptake of water by astrocytes but not by neurons, whereas both cell types swell as a consequence of lost blood flow (ischemia). Either hypoosmolality or ischemia can displace the brain downwards, potentially causing death. However, these disorders are fundamentally different at the cellular level. Astrocytes osmotically swell or shrink because they express functional water channels (aquaporins), whereas neurons lack functional aquaporins and thus maintain their volume. Yet both neurons and astrocytes immediately swell when blood flow to the brain is compromised (cytotoxic edema) as following stroke onset, sudden cardiac arrest, or traumatic brain injury. In each situation, neuronal swelling is the direct result of spreading depolarization (SD) generated when the ATP-dependent sodium/potassium ATPase (the Na+/K+ pump) is compromised. The simple, and incorrect, textbook explanation for neuronal swelling is that increased Na+ influx passively draws Cl− into the cell, with water following by osmosis via some unknown conduit. We first review the strong evidence that mammalian neurons resist volume change during acute osmotic stress. We then contrast this with their dramatic swelling during ischemia. Counter-intuitively, recent research argues that ischemic swelling of neurons is non-osmotic, involving ion/water cotransporters as well as at least one known amino acid water pump. While incompletely understood, these mechanisms argue against the dogma that neuronal swelling involves water uptake driven by an osmotic gradient with aquaporins as the conduit. Promoting clinical recovery from neuronal cytotoxic edema evoked by spreading depolarizations requires a far better understanding of molecular water pumps and ion/water cotransporters that act to rebalance water shifts during brain ischemia.

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Vascular adaptations to hypoxia: molecular and cellular mechanisms regulating vascular tone

Essays in Biochemistry ◽

10.1042/bse0430105 ◽

2007 ◽

Vol 43 ◽

pp. 105-120 ◽

Cited By ~ 8

Author(s):

Michael L. Paffett ◽

Benjimen R. Walker

Keyword(s):

Vascular Tone ◽

Cellular Proliferation ◽

Hypoxic Pulmonary Vasoconstriction ◽

Hypoxia Inducible Factor ◽

Systemic Circulation ◽

Cellular Mechanisms ◽

Hypoxia Inducible Factor 1 ◽

Pulmonary Vasoconstriction ◽

Adaptive Mechanisms ◽

Adaptive Processes

Several molecular and cellular adaptive mechanisms to hypoxia exist within the vasculature. Many of these processes involve oxygen sensing which is transduced into mediators of vasoconstriction in the pulmonary circulation and vasodilation in the systemic circulation. A variety of oxygen-responsive pathways, such as HIF (hypoxia-inducible factor)-1 and HOs (haem oxygenases), contribute to the overall adaptive process during hypoxia and are currently an area of intense research. Generation of ROS (reactive oxygen species) may also differentially regulate vascular tone in these circulations. Potential candidates underlying the divergent responses between the systemic and pulmonary circulations may include Nox (NADPH oxidase)-derived ROS and mitochondrial-derived ROS. In addition to alterations in ROS production governing vascular tone in the hypoxic setting, other vascular adaptations are likely to be involved. HPV (hypoxic pulmonary vasoconstriction) and CH (chronic hypoxia)-induced alterations in cellular proliferation, ionic conductances and changes in the contractile apparatus sensitivity to calcium, all occur as adaptive processes within the vasculature.

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Flavonoids in adipose tissue inflammation and atherosclerosis: one arrow, two targets

Clinical Science ◽

10.1042/cs20200356 ◽

2020 ◽

Vol 134 (12) ◽

pp. 1403-1432 ◽

Cited By ~ 2

Author(s):

Manal Muin Fardoun ◽

Dina Maaliki ◽

Nabil Halabi ◽

Rabah Iratni ◽

Alessandra Bitto ◽

...

Keyword(s):

Adipose Tissue ◽

Fruits And Vegetables ◽

Metabolic Diseases ◽

Therapeutic Agents ◽

Adipose Tissue Inflammation ◽

Cellular Mechanisms ◽

Tissue Inflammation ◽

Cholesterol Levels ◽

Naturally Occurring ◽

Pro Inflammatory Cytokines

Abstract Flavonoids are polyphenolic compounds naturally occurring in fruits and vegetables, in addition to beverages such as tea and coffee. Flavonoids are emerging as potent therapeutic agents for cardiovascular as well as metabolic diseases. Several studies corroborated an inverse relationship between flavonoid consumption and cardiovascular disease (CVD) or adipose tissue inflammation (ATI). Flavonoids exert their anti-atherogenic effects by increasing nitric oxide (NO), reducing reactive oxygen species (ROS), and decreasing pro-inflammatory cytokines. In addition, flavonoids alleviate ATI by decreasing triglyceride and cholesterol levels, as well as by attenuating inflammatory mediators. Furthermore, flavonoids inhibit synthesis of fatty acids and promote their oxidation. In this review, we discuss the effect of the main classes of flavonoids, namely flavones, flavonols, flavanols, flavanones, anthocyanins, and isoflavones, on atherosclerosis and ATI. In addition, we dissect the underlying molecular and cellular mechanisms of action for these flavonoids. We conclude by supporting the potential benefit for flavonoids in the management or treatment of CVD; yet, we call for more robust clinical studies for safety and pharmacokinetic values.

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