Lipoprotein apheresis reduces circulating galectin-3 in humans.

BACKGROUND: Plasma galectin-3 (Gal-3) is elevated in, and drives, diverse systemic inflammatory disorders, including cancer, cardiovascular diseases, and diabetes. Circulating Gal-3 promotes tumorigenesis and metastasis, as well as fibrotic remodeling, and is a promising therapeutic target. Apheresis has proven utility in reducing circulating disease-promoting substances, exemplified by the success of lipoprotein apheresis (LA) in abrogating cardiovascular disease progression in drug-refractory hypercholesterolemia patients. We compared the clinical utility of two FDA-approved LA systems in reducing plasma Gal-3 in humans. METHODS: Plasma Gal-3 levels were assessed by ELISA in blinded samples drawn pre- and post-apheresis from hypercholesterolemia patients (n = 10/group) undergoing therapeutic LA using either a heparin-induced extracorporeal LDL precipitation (HELP) or dextran sulfate-adsorption (DSA) system. RESULTS: Mean baseline plasma Gal-3 concentrations (±SD) were 14.3 ± 5.1 (range 6.6-22.8) and 14.5 ± 2.8 (range 10.6-19.8) ng/mL in the HELP and DSA groups, respectively. Post-apheresis Gal-3 levels were respectively reduced by 19.4% and 22.7% in the HELP (P = 0.0094) and DSA (P = 0.0027) systems (paired t-tests); the difference between devices was insignificant (P = 0.5288; Mann-Whitney). Post-treatment Gal-3 levels were 11.3 ± 3.7 (HELP; range 4.5-16.3) and 11.3 ± 3.8 (DSA; range 7.5-20.7) ng/mL. CONCLUSIONS: Circulating Gal-3 levels showed a statistically significant decrease in humans undergoing therapeutic LA. Although absolute Gal-3 reduction was ≈19-23%, this effect, combined with reducing atherogenic LDL and other inflammation mediators (e.g., CRP, fibrinogen, Lp-PLA2 ), may enhance apheresis clinical benefits. Applying new Gal-3-specific extraction technologies to apheresis may be advantageous in treating diverse pathologies that are promoted by elevated plasma Gal-3. J. Clin. Apheresis 31:388-392, 2016. © 2015 Wiley Periodicals, Inc.

Resveratrol and calcium signaling: molecular mechanisms and clinical relevance.

Resveratrol is a naturally occurring compound contributing to cellular defense mechanisms in plants. Its use as a nutritional component and/or supplement in a number of diseases, disorders, and syndromes such as chronic diseases of the central nervous system, cancer, inflammatory diseases, diabetes, and cardiovascular diseases has prompted great interest in the underlying molecular mechanisms of action. The present review focuses on resveratrol, specifically its isomer trans-resveratrol, and its effects on intracellular calcium signaling mechanisms. As resveratrol's mechanisms of action are likely pleiotropic, its effects and interactions with key signaling proteins controlling cellular calcium homeostasis are reviewed and discussed. The clinical relevance of resveratrol's actions on excitable cells, transformed or cancer cells, immune cells and retinal pigment epithelial cells are contrasted with a review of the molecular mechanisms affecting calcium signaling proteins on the plasma membrane, cytoplasm, endoplasmic reticulum, and mitochondria. The present review emphasizes the correlation between molecular mechanisms of action that have recently been identified for resveratrol and their clinical implications.

Presenilins regulate the cellular activity of ryanodine receptors differentially through isotype-specific N-terminal cysteines.

Presenilins (PS), endoplasmic reticulum (ER) transmembrane proteins, form the catalytic core of γ-secretase, an amyloid precursor protein processing enzyme. Mutations in PS lead to Alzheimer's disease (AD) by altering γ-secretase activity to generate pathologic amyloid beta and amyloid plaques in the brain. Here, we identified a novel mechanism where binding of a soluble, cytosolic N-terminal domain fragment (NTF) of PS to intracellular Ca(2+) release channels, ryanodine receptors (RyR), controls Ca(2+) release from the ER. While PS1NTF decreased total RyR-mediated Ca(2+) release, PS2NTF had no effect at physiological Ca(2+) concentrations. This differential function and isotype-specificity is due to four cysteines absent in PS1NTF, present, however, in PS2NTF. Site-directed mutagenesis targeting these cysteines converted PS1NTF to PS2NTF function and vice versa, indicating differential RyR binding. This novel mechanism of intracellular Ca(2+) regulation through the PS-RyR interaction represents a novel target for AD drug development and the treatment of other neurodegenerative disorders that critically depend on RyR and PS signaling.