Entity

Time filter

Source Type


Altura B.M.,Center for Cardiovascular and Muscle Research | Altura B.M.,New York University | Altura B.M.,Defense Systems | Perez-Albela J.L.,Instituto Bien Of Salud | And 3 more authors.
American Journal of Physiology - Heart and Circulatory Physiology | Year: 2012

The present study tested the hypotheses that 1) short-term dietary deficiency (MgD) of magnesium (21 days) would result in the upregulation of ceramide synthase (CS) in left ventricular (LV), right ventricular, atrial, and aortic smooth muscle, as well as induce a synthesis/release of select cytokines and chemokines into the LV and aortic smooth muscle and serum; 2) exposure of primary cultured vascular smooth muscle cells (VSMCs) to low extracellular Mg concentration would lead to the synthesis/release of select cytokines/chemokines, activation of N-SMase, and the de novo synthesis of ceramide; and 3) inhibition of CS by fumonisin B1 (FB1) or inhibition of neutral sphingomyelinase (N-SMase) by scyphostatin (SCY) in VSMCs exposed to low Mg would result in reductions in the levels of the cytokines/chemokines and lowered levels of ceramide concomitant with inhibition of NF-kB activation. The data indicated that short-term MgD (10% normal dietary intake) resulted in the upregulation of CS in ventricular, atrial, and aortic smooth muscles coupled to the synthesis/release of 12 different cytokines/chemokines, as well as activation of NF-kB in the LV and aortic smooth muscle and sera; even very low levels of water-borne Mg (e.g., 15 mg·l -1·day -1) either prevented or ameliorated the upregulation and synthesis of the cytokines/chemokines. Our experiments also showed that VSMCs exposed to low extracellular Mg resulted in the synthesis of 5 different cytokines and chemokines concomitant with synthesis/release of ceramide. However, inhibition of the synthesis and release of ceramide by either FB1 or SCY attenuated, markedly, the generation of ceramide, release of the cytokines/chemokines, and activation of NF-kB (as measured by activated p65 and cRel). © 2012 the American Physiological Society. Source


Shah N.C.,New York University | Liu J.-P.,New York University | Iqbal J.,New York University | Hussain M.,New York University | And 10 more authors.
International Journal of Clinical and Experimental Medicine | Year: 2011

The present work tested the hypothesis that short-term (S-T) dietary deficiency of magnesium (Mg) (21 days) in rats would: 1) result in reduction in serum(s) sphingomyelin (SM) and changes in several blood lipids, HDLcholesterol (HDL-C) and phosphatidylcholine (PC) concomitant with elevations in s cholesterol (chol), s LDL+VLDL and trigycerides (TG), as well as reduction in the PC/cholesterol ratio; 2) lead to oxidative stress,characterized by reductions in glutathione (glut) content in the various chambers of the heart and activation of e-NOS and n-NOS in the atria, ventricles and aortic smooth muscle (ASM); 3) produce early cardiac damage characterized by leakage of creatine kinase (CK) and lactic dehydrogenase (LDH); and 4) demonstrate that these pathophysiological changes are a result of profound reductions in s ionized Mg (Mg2+) and activation of the SM-ceramide pathway. In addition, we hypothesized that: 1) exposure of primary cultured vascular smooth muscle cells (VSMCs) to low extracellular Mg2+ would lead to de novo synthesis of ceramide and activation of NO synthase with reduction in glut, both of which would be attenuated by inhibition of sphingomyelinase (SMase) and serine palmitoyl CoA transferase (SPT); and 2) low levels of Mg2+ added to the drinking water would either prevent or ameliorate these manifestations. Our data indicate that S-T Mg deficiency resulted in reductions in s Mg2+, SM, PC, HDL-C and the PC/chol ratio concomitant with decreases in tissue levels of glut, leakage of cardiac CK and LDH, as well as activation of e-NOS and n-NOS in all chambers of the heart and ASM. The greater the reduction in s Mg2+, the greater the effects on all parameters analyzed; very significant correlations to levels of s SM and Mg2+ were found with all of the serum and tissue biochemical -molecular analytes measured. Our experiments also showed that VSMCs exposed to low Mg2+resulted in activation of NO synthase, loss of glut and de novo synthesis of ceramide which were attenuated by inhibitors of SMase and SPT. Low levels of drinking water Mg2+ (e.g., 15 ppm) were cardio-and vascular protective. We believe these new findings support our concept of an important role for the SM-ceramide pathway in the manifestations of Mg deficiency and atherogenesis. Source


Altura B.M.,New York University | Altura B.M.,Defense Systems | Shah N.C.,New York University | Li Z.,New York University | And 4 more authors.
American Journal of Physiology - Heart and Circulatory Physiology | Year: 2010

The present work tested the hypothesis that a short-term dietary deficiency of magnesium (Mg) (21 days) in rats would result in the upregulation of the two major subunits of serine palmitoyl-CoA-transferase, serine palmitoyl transferase (SPT 1) and SPT 2 (the rate-limiting enzymes responsible for the de novo biosynthesis of ceramides) in left ventricular, right ventricular, and atrial heart muscle and abdominal aortic smooth muscle, as well as induce a reduction in serum sphingomyelin concomitant with the release of mitochondrial cytochrome c (Cyto c) in these tissues. Our data indicate that short-term Mg deficiency (MgD) resulted in an upregulation of SPT 1 and SPT 2, concomitant with a very significant release of Cyto c in left ventricular, right ventricular, atrial, and abdominal aortic smooth muscle. Short-term MgD also produced a lowering of serum sphingomyelin and ionized Mg. The greater the reduction in serum ionized Mg, the greater the upregulation of SPT 1 and 2 and the more the increase in free Cyto c. The data suggest that MgD, most likely, causes a biosynthesis of ceramides via two pathways in cardiovascular tissues, viz., via the activation of serine palmitoyl-CoA-transferase and sphingomyelinase, which lead to apoptotic events via intrinsic (present study) and extrinsic pathways (previous studies). Low levels of drinking water Mg were cardio- and vasculoprotective. Copyright © 2010 the American Physiological Society. Source


Altura B.M.,New York University | Altura B.M.,Defense Systems | Shah N.C.,New York University | Shah G.J.,New York University | And 6 more authors.
International Journal of Clinical and Experimental Medicine | Year: 2014

Numerous recent,epidemiological studies reveal that Western populations are growing more and more deficient in daily Mg intake which have been linked to etiology of cardiovascular (CV) diseases. A growing body of evidence suggests that a major missing link to this dilemma may reside within the sphingolipid-ceramide pathways. For the past 25 years, our labs have been focusing on these pathways in Mg-deficient mammals. The objective of this paper is two-fold: 1) to test various hypotheses and 2) to review the current status of the field and how protein kinase C isoforms may be pivotal to solving some of the CV attributes of Mg deficiency. Below, we test the hypotheses that: 1) short-term dietary deficiency of magnesium (MgD) would result in the upregulation of protein kinase C (PKC) isoforms in left ventricular (LV) and aortic smooth muscle (ASM) and serum; 2) MgD would result in a release of select cytokines and an upregulation of NF-kB in LV and ASM, and in primary cultured aortic smooth muscle cells (PCASMC); 3) MgD would result in an activation of the sphingolipid salvage pathway in LV and ASM, and in PCASMC; 4) MgD would result in a synthesis of sphingosine, but not sphinganine, in PCASMC which could be inhibited by fumonisin B1 (FB) an inhibitor of ceramide synthase (CS), but not scyphostatin an inhibitor of neutral sphingomyelinase (N-SMase); 5) incubation of PCASMC (in low Mg2+) with the PKC-mimic PMA would result in release and synthesis of NF-kB, cytokines, and ceramide but not sphingosine. The new data indicate that short-term MgD (10% normal dietary intake) result in an upregulation of all three classes of PKC isoforms in LV, aortic muscle and in serum coupled to the upregulation of ceramide, NF-kB activation, and cytokines. High degrees of linear correlation were found to exist between upregulation of PKC isoforms, p65 and cytokine release, suggesting cross-talk between these molecules and molecular pathways. Our experiments with PCASMCs demonstrated that MgD caused a pronounced synthesis of sphingosine (but not sphinganine), which could be inhibited with fumonisin B1, but not by scyphostatin; use of PMA stimulation released ceramide but not sphingosine suggesting a role for the "sphingolipid salvage pathway" in MgD vascular muscle. Use of different PKC pharmacological inhibitors suggested that although all three classes of PKC molecules, i.e., classical, novel, and atypical, play roles in MgD-induced synthesis/release of ceramide, sphingosine, and cytokines as well as activation of NF-kB, to varying degrees, PKC-zeta appears to play a greater role in these events than any of the other PKC isoforms; a specific PKC-zeta inhibitory peptide inhibited formation of sphingosine. Even low levels of water-borne Mg (e.g., 15 mg/l/day) either prevented or ameliorated the upregulation of all three classes of PKC isoforms. An attempt is made to integrate our new data with previous information in order to possibly explain many of the cardiovascular effects of MgD. Source


Altura B.M.,New York University | Altura B.M.,Defense Systems | Shah N.C.,New York University | Li Z.,New York University | And 7 more authors.
American Journal of Physiology - Heart and Circulatory Physiology | Year: 2010

The present study tested the hypotheses that 1) short-term dietary deficiency of magnesium (21 days) in rats would result in the upregulation of sphingomyelin synthase (SMS) and p53 in cardiac and vascular (aortic) smooth muscles, 2) low levels of Mg 2+ added to drinking water would either prevent or greatly reduce the upregulation of both SMS and p53, 3) exposure of primary cultured vascular smooth muscle cells (VSMCs) to low extracellular Mg 2+ concentration ([Mg 2] o) would lead to the de novo synthesis of ceramide, 4) inhibition of either SMS or p53 in primary culture VSMCs exposed to low [Mg 2+] o would lead to reductions in the levels of de novo ceramide synthesis, and 5) inhibition of sphingomyelin palmitoyl-CoA transferase (SPT) or ceramide synthase (CS) in primary cultured VSMCs exposed to low [Mg 2+] o would lead to a reduction in the levels of de novo ceramide synthesis. The data indicated that short-term magnesium deficiency (10% normal dietary intake) resulted in the upregulation of SMS and p53 in both ventricular and aortic smooth muscles; even very low levels of water-borne Mg 2+ (e.g., 15 mg·l -1·day -1) either prevented or ameliorated the upregulation in SMS and p53. Our experiments also showed that VSMCs exposed to low [Mg 2+] o resulted in the de novo synthesis of ceramide; the lower the [Mg 2+] o, the greater the synthesis of ceramide. In addition, the data indicated that inhibition of either SMS, p53, SPT, or CS in VSMCs exposed to low [Mg 2+] o resulted in marked reductions in the de novo synthesis of ceramide. Copyright © 2010 the American Physiological Society. Source

Discover hidden collaborations