Publications (2)4.99 Total impact
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Article: 1-Methylnicotinamide (MNA) prevents endothelial dysfunction in hypertriglyceridemic and diabetic rats.
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ABSTRACT: For many years, 1-methylnicotinamide (MNA), a primary metabolite of nicotinamide, has been considered inactive. Recently however, it has been discovered that MNA possesses anti-thrombotic and anti-inflammatory activity. In the present study we investigated whether chronic administration of MNA to hypertriglyceridemic or diabetic rats would reverse endothelial dysfunction characterized by the impairment of nitric oxide (NO)-dependent vasodilatation. Hypertriglyceridemia in rats was induced by fructose-rich (60%) diet, while diabetes was induced by streptozotocin injection (70 mg/kg). After eight weeks, in hypertriglyceridemic or diabetic rats treated or non-treated with MNA(100 mg/kg), we analyzed the magnitude of endothelium-dependent or endothelium-independent vasodilatation in aorta induced by acetylcholine or S-nitroso-N-acetyl-penicillamine (SNAP), respectively, as well as plasma concentration of: cholesterol, triglycerides, glucose, HbA(1c), fructosamine, peptide C, endogenous MNA and its metabolites (M2PY, M4PY). In diabetic rats plasma concentration of glucose, HbA(1c) and fructosamine was elevated (402.08 +/- 19.01 vs. 82.06 +/- 5.41 mg/dl, p < 0.001; 9.55 +/- 0.56 vs. 4.93 +/- 0.24%, p = 0.052 and 2.53 +/- 0.10 vs. 1.14 +/- 0.06 mmol DTF/mg protein, p < 0.001 in diabetic and control rats, respectively). In hypertriglyceridemic rats plasma concentration of triglycerides was elevated (4.25 +/- 0.27 vs. 1.55 +/- 0.12 mmol/l, p < 0.001 in hypertriglyceridemic and control rats, respectively). In both models the NO-dependent vasodilatation in aorta induced by acetylcholine was significantly impaired as compared to control rats, while the response to SNAP was largely preserved. In hypertriglyceridemic rats, 4 weeks of treatment with MNA(100 mg/kg, po) resulted in a three to six-fold increase in endogenous levels of MNA and its metabolites (M2PY and M4PY), the fall in triglycerides concentration in plasma (from 4.25 +/- 0.27 to 2.22 +/- 0.14 mmol/l, p < 0.001), and the preservation of the NO-dependent vasodilatation. In diabetic rats chronic treatment with MNA also prevented the impairment of NO-dependent vasodilatation, while it displayed only a mild effect on hyperglycemia and did not lower triglycerides concentration. In summary, MNA treatment decreased plasma triglycerides concentration in hypertriglyceridemic, but not in diabetic rats, while it prevented the development of endothelial dysfunction in aorta in both of these models. Accordingly, the ability of MNA to reverse endothelial dysfunction seems to be independent of its hypolipemic activity.Pharmacological reports: PR 60(1):127-38. · 2.44 Impact Factor -
Article: 1-Methylnicotinamide and nicotinamide: two related anti-inflammatory agents that differentially affect the functions of activated macrophages.
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ABSTRACT: 1-Methylnicotinamide (MNA), a major metabolite of nicotinamide (NA), is known to exert anti-inflammatory effects in vivo. Treatment of inflammatory skin diseases by topical application of MNA provides certain advantages over the use of NA. However, in contrast to NA, the molecular mechanisms of the anti-inflammatory properties of MNA are not well known. In this study the influence of exogenous MNA and NA in vivo on the generation of inflammatory mediators by macrophages (Mvarphi) was investigated. Peritoneal Mvarphi of CBA/J mice were activated in vitro with lipopolysaccharide and incubated with MNA or NA. The effect of these compounds on biological functions of Mvarphi was measured by evaluation of the production of reactive oxygen species (ROS) by luminol-dependent chemiluminescence, cytokines and prostaglandin E(2) (PGE(2)) by ELISA, and nitric oxide (NO) by the Griess method. Moreover, the expressions of inducible NO synthase and cyclooxygenase-2 were measured by Western blotting. It was shown that at non-cytotoxic concentrations, NA inhibits the production of a variety of pro-inflammatory agents, such as tumor necrosis factor alpha, interleukin 6, NO, PGE(2), and the generation of ROS. In contrast to NA, exogenous MNA inhibited only the generation of ROS, while its effect on the synthesis of other mediators was negligible. These results indicate that the anti-inflammatory properties of MNA demonstrated previously in vivo do not depend on its capacity to suppress the functions of immune cells, but more likely may be related to its action on vascular endothelium. The authors suggest that the limited permeability for exogenous MNA, in contrast to that for NA, may be responsible for its lack of suppressor activity against Mvarphi.Archivum Immunologiae et Therapiae Experimentalis 56(2):127-34. · 2.54 Impact Factor
