Folate in smokers.

Blood folate concentration is decreased by tobacco smoking and presumably secondhand smoke. Because low folate concentration is associated with hyperhomocysteinemia, both are emerging as important and independent risk factors for atherosclerosis as well as prediction of early coronary artery disease. The primary cause of low folate concentration in smokers might be related to lifestyle and dietary habits. Smokers tend to consume fewer folate-rich fruits and vegetables vs non-smokers. Adverse cardiovascular health is generally attributed to toxic gases, particulates, and tars generated from tobacco smoking. Although low folate concentration and hyperhomocysteinemia are typically found in smokers, their role in this pathophysiologic process remains controversial. In fact, several studies failed to demonstrate a beneficial effect of daily folic acid supplementation as a homocysteine-lowering therapy on cardiovascular outcome even in smokers. In this review, we investigate the relationship between folate status and smoking.

Inhibition of mineralocorticoid receptor is a renoprotective effect of the 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor pitavastatin.

OBJECTIVE: The mineralocorticoid receptor has been implicated in the pathogenesis of chronic cardiorenal disease. Statins improve renal remodeling and dysfunction in patients with proteinuric kidney diseases. We aimed to clarify the beneficial effects and mechanisms of action of statins in renal insufficiency. METHODS AND RESULTS: Dahl salt-sensitive rats fed a high-salt diet were treated from 12 to 20 weeks of age with vehicle, the reduced nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase inhibitor apocynin, the synthetic cathepsin inhibitor E64d, or a low or high dosage of pitavastatin (1 or 3 mg/kg daily). Rats fed a low-salt diet served as controls. Rats on the high-salt diet developed massive proteinuria and glomerulosclerosis; these changes were attenuated by both doses of pitavastatin. The amounts of mRNAs or proteins for mineralocorticoid receptor, angiotensin-converting enzyme, angiotensin II type 1 receptor (AT1R), monocyte chemoattractant protein-1, osteopontin, macrophage infiltration, and NADPH subunits (gp91phox, p22phox, and Rac1) were significantly higher in the failing kidneys of vehicle-treated rats than in the kidneys of control rats. Either dose of pitavastatin significantly attenuated these changes. These effects of pitavastatin were mimicked by those of apocynin and E64d. Pretreatment with pitavastatin and apocynin inhibited mRNA and protein of mineralocorticoid receptor induced by angiotensin II in cultured podocytes. CONCLUSION: The beneficial effects of pitavastatin are likely attributable, at least in part, to attenuation of the mineralocorticoid receptor-dependent inflammatory mediator, matrix protein, and cathepsin expressions induced by AT1R-mediated NADPH oxidase activation in the kidneys of a salt-induced hypertensive Dahl salt-sensitive rat model.

Low folate levels may be an atherogenic factor regardless of homocysteine levels in young healthy nonsmokers.

Low folate and high homocysteine levels are emerging as important risk factors for atherosclerosis and predictors of early coronary heart disease. We evaluated folate and homocysteine levels, compared them with endothelial function, and analyzed their association with the methylenetetrahydrofolate reductase (MTHFR) and endothelial nitric oxide synthase genotypes. We recruited 71 young healthy male nonsmokers without overt cardiovascular or renal disease. Plasma homocysteine levels were enhanced 2-fold in the subjects with the MTHFR 677T/T compared with the others (P = .0001) and also enhanced in the subjects with the endothelial nitric oxide synthase -786C allele (P = .031). Homocysteine levels were independently predicted only by the MTHFR genotype. A relationship between folate and homocysteine levels was not significant. Plasma folate levels were associated independently either with high-density lipoprotein cholesterol levels or with endothelial function in the brachial artery. These results suggest that low folate levels may be a risk factor for cardiovascular diseases regardless of homocysteine levels and that the subjects with lower folate levels should be recommended for dietary folic acid supplementation to elevate endothelial function and probably increase high-density lipoprotein cholesterol levels.

Prognostic impact of bim, puma, and noxa expression in human colon carcinomas.

PURPOSE: Proapoptotic BH3-only proteins (Bim, Bad, Bid, Puma, and Noxa) initiate apoptosis by binding to regulatory sites on antiapoptotic Bcl-2 proteins, directly neutralizing their cytoprotective function. Expression of these proteins in colon cancer patients may account for differences in recurrence and survival rates. EXPERIMENTAL DESIGN: Archival tumor-node-metastasis stage II and III primary colon carcinomas from patients treated in 5-fluorouracil-based adjuvant therapy trials were studied. Immunohistochemical analysis of Bim, Puma, and Noxa proteins was done using tissue microarrays (n = 431). Immunoscores were determined and correlated with clinicopathologic variables and disease-free survival (DFS) and overall survival (OS) rates. RESULTS: Elevated expression of proapoptotic Bim (hazard ratio, 0.65; 95% confidence interval, 0.44-0.97; P = 0.033) and Puma (hazard ratio, 0.59; 95% confidence interval, 0.37-0.93; P = 0.022), but not Noxa, proteins in the tumor cytoplasm was significantly associated with more favorable OS in a univariate analysis, and elevated Bim expression was also associated with better DFS (P = 0.023). Patient age, tumor stage, and histologic grade were also prognostic. Multivariate Cox analysis showed that Bim (DFS, P = 0.030; OS, P = 0.045) and Puma (OS, P = 0.037) expression were independent predictors of OS after adjustment for histologic grade, tumor stage, age, and treatment. Furthermore, the combined variable of Bim and Puma was highly discriminant for both DFS (P = 0.0034) and OS (P = 0.0011). CONCLUSIONS: The proapoptotic BH3-only proteins Bim and Puma can provide prognostic information for stage II and III colon cancer patients receiving 5-fluorouracil-based adjuvant chemotherapy. Furthermore, our results support BH3-only proteins as molecular targets of novel anticancer drugs.

Expression level of thymidylate synthase mRNA reflects 5-fluorouracil sensitivity with low dose and long duration in primary colorectal cancer.

OBJECTIVES: To investigate the prognostic marker for the adjuvant chemotherapy of primary colorectal carcinoma. METHODS: Primary colorectal cancer tissue from 24 patients was investigated to evaluate the relationship between the mRNA expression level of several 5-fluorouracil (5-FU)-related metabolic enzymes (thymidylate synthase, TS; dihydropyrimidine dehydrogenase, DPD; and thymidine phosphorylase, TP) and chemosensitivity to two different 5-FU doses and duration (1: 5-FU concentration 1.0 microg/mL (7.68 microM), 24 h exposure and 2: 5-FU concentration 0.3 microg/mL (2.30 microM), 144 h exposure). Chemosensitivity and mRNA expression levels were measured using collagen gel droplet embedded culture drug sensitivity tests and real-time quantitative reverse transcription-polymerase chain reaction. Clinicopathological features and chemosensitivity were also compared. RESULTS: The TS mRNA expression level was significantly higher in the 5-FU resistant group (T/C > 60%) compared with the 5-FU sensitive group (T/C < 60%) in both 5-FU regimens (1: 5.03 +/- 0.92 vs. 1.58 +/- 0.76, p < 0.01, 2: 4.88 +/- 0.91 vs. 0.96 +/- 0.20, p < 0.001). The group with the higher TS mRNA expression level (>3.83, the average) were more resistant to both 5-FU regimens than those with lower TS mRNA (<3.83) (1: T/C = 80 vs. 66%, p = 0.11, 2: T/C = 89 vs. 64%, p < 0.005). The TS mRNA expression level inversely correlated with the sensitivity to the latter 5-FU regimen (R = 0.577, p < 0.01). There were no relationships between chemosensitivity to 5-FU and the mRNA expression level of DPD and TP and clinicopathological factors. CONCLUSIONS: The TS mRNA expression level might be a good marker of chemosensitivity to 5-FU in primary colorectal cancer, especially the sensitivity to low dose 5-FU with a long duration.

Pressure overload-induced cardiomyopathy in heterozygous carrier mice of carnitine transporter gene mutation.

Primary systemic carnitine deficiency is an autosomal recessive disorder caused by a decreased renal reabsorption of carnitine because of mutations of the carnitine transporter OCTN2 gene, and hypertrophic cardiomyopathy is a common clinical feature of homozygotes. Although heterozygotes for OCTN2 mutations are generally healthy with normal cardiac performance, heterozygotes may be at risk for cardiomyopathy in the presence of additional risk factors, such as hypertension. To test this hypothesis, we investigated the effects of surgically induced pressure overload on the hearts of heterozygous mutants of a murine model of OCTN2 mutation, juvenile visceral steatosis mouse (jvs/+). Eleven-week-old jvs/+ mice and age-matched wild-type mice were used. At baseline, there were no differences in physical characteristics between wild-type and jvs/+ mice. However, plasma and myocardial total carnitine levels in jvs/+ mice were lower than in wild-type mice. Both wild-type and jvs/+ mice were subjected to ascending aortic constriction with or without 1% l-carnitine supplementation for 4 weeks. At 4 weeks after ascending aortic constriction, jvs/+ mice showed an exaggeration of cardiac hypertrophy and pulmonary congestion, further increased gene expression of atrial natriuretic peptide in the left ventricles, further deterioration of left ventricular fractional shortening, reduced myocardial phosphocreatine:adenosine triphosphate ratio, and increased mortality compared with wild-type mice; l-carnitine supplementation prevented these changes in jvs/+ mice subjected to ascending aortic constriction. In conclusion, cardiomyopathy and heart failure with energy depletion may be induced by pressure overload in heterozygotes for OCTN2 mutations and could be prevented by l-carnitine supplementation.

Combined therapy with PPARalpha agonist and L-carnitine rescues lipotoxic cardiomyopathy due to systemic carnitine deficiency.

OBJECTIVE: Peroxisome proliferator-activated receptors (PPAR) are ligand-activated transcription factors that belong to the nuclear hormone receptor superfamily and are key regulators of fatty acid oxidation (FAO) in the heart. Systemic carnitine deficiency (SCD) causes disorders of FAO and induces hypertrophic cardiomyopathy with lipid accumulation. We hypothesized that activation of PPARalpha by fenofibrate, a PPARalpha agonist, in addition to conventional L-carnitine supplementation may exert beneficial effects on the lipotoxic cardiomyopathy in juvenile visceral steatosis (JVS) mouse, a murine model of SCD. METHODS: Both wild-type (WT) and JVS mice were fed a normal chow, 0.2% fenofibrate containing chow (FE), a 0.1% L-carnitine containing chow (CA) or a 0.1% L-carnitine + 0.2% fenofibrate containing chow (CA + FE) from 4 weeks of age. Four to 8 animals per group were used for each experiment and 9 to 11 animals per group were used for survival analysis. RESULTS: At 8 weeks of age, JVS mice exhibited marked ventricular hypertrophy, which was more attenuated by CA + FE than by CA or FE alone. CA + FE markedly reduced the high plasma and myocardial triglyceride levels and increased the low myocardial ATP content to control levels in JVS mice. In JVS mice, myocardial 1,2-diacylglycerol (DAG) was significantly increased and showed a distinct fatty acid composition with elevation of 18:1(n-7,9) and 18:2(n-6) fatty acids compared with that in WT mice. CA + FE significantly altered the fatty acid composition of DAG and inhibited the membrane translocation of cardiac protein kinase C beta2 in JVS mice. Furthermore, CA + FE prevented the progressive left ventricular dysfunction and dramatically improved the survival rate in JVS mice (survival rate at 400 days after birth: 89 vs. 0%, P < 0.0001). CONCLUSIONS: PPARalpha activation, in addition to l-carnitine supplementation, may rescue the detrimental lipotoxic cardiomyopathy in SCD by improving cardiac energy and lipid metabolism as well as systemic lipid metabolism.

Inhibition of COX-2 prevents hypertension and proteinuria associated with a decrease of 8-iso-PGF2alpha formation in L-NAME-treated rats.

BACKGROUND: The inhibition of nitric oxide (NO) exerts injurious effects on the cardiovascular system by several mechanisms, such as the activation of the renin-angiotensin system, oxidative stress, and inflammatory cytokines. We examined whether COX-2, an inducible isoform of cyclooxygenase, is associated with the pathogenesis observed in N(omega)-nitro-L-arginine methyl ester (L-NAME)-induced hypertensive rats. METHODS: Three groups of 8-week-old male Sprague-Dawley rats were studied (n = 6 in each group): group 1, untreated controls; group 2, treated with L-NAME (1 g/l for 3 weeks, p.o.); and group 3, L-NAME co-treated with COX-2 inhibitor NS-398 (5 mg/kg per day, i.p.). The L-NAME-induced expression of COX-2 mRNA and protein was semi-quantified in the kidneys and the thoracic aorta. Urinary excretion of the prostaglandin 6-keto PGF(1alpha), thromboxane B2 (TXB2), and prostaglandin E2 (PGE2) was measured in the three groups. Moreover, urinary excretion of 8-iso-PGF(2alpha), a potent vasoconstricting arachidonic acid metabolite acting through thromboxane A (TXA) receptor activation, proposed recently as a marker of oxidative stress, was also measured. RESULTS: L-NAME induced significant increases in systolic blood pressure (P< 0.01), urinary protein (P< 0.05), and renal excretion of 8-iso-PGF(2alpha)(P< 0.01), compared with the control. In L-NAME-treated rats, the levels of COX-2 mRNA and protein were more than 50% higher in the kidneys (P< 0.05), and six-fold higher in the thoracic aorta (P< 0.01) than in control rats. NS-398 significantly ameliorated an increase in systolic blood pressure (P< 0.01) and urinary protein (P< 0.05) induced by L-NAME. CONCLUSIONS: These data indicate that an increase in COX-2 expression might have a hypertensive effect, partly associated with 8-iso-PGF(2alpha) formation in l-NAME-treated rats.

Dietary fish oil does not prevent doxorubicin-induced cardiomyopathy in rats.

BACKGROUND: Dietary fish oil potentiates the susceptibility of cellular membranes to lipid peroxidation, although it is also known to have beneficial effects on the development of cardiovascular diseases. OBJECTIVE: The effects of dietary fish oil against doxorubicin-induced cardiomyopathy, in which free radicals and lipid peroxidation are involved, were investigated in rats. ANIMALS AND METHODS: Sprague-Dawley rats (100 g) were fed a standard diet or a high fish oil diet (containing 10% fish oil) throughout the experimental period. Four weeks after starting each diet, experimental rats were treated with doxorubicin (cumulative dose 15 mg/kg) or vehicle (0.28 M dextrose solution). After three weeks of doxorubicin treatment, the cardiac performance, myocardial lipid peroxidation and myocardial vitamin E level were assessed. RESULTS: Compared with control rats, doxorubicin-treated rats showed a significantly increased mortality rate (P<0.05), and significantly decreased systolic blood pressure and left ventricular fractional shortening (P<0.01). The myocardial thiobarbituric acid-reactive substance level was significantly higher in doxorubicin-treated rats than in control rats (P<0.01), while the myocardial vitamin E level was significantly lower (P<0.05). Dietary fish oil enhanced the myocardial lipid peroxidation caused by doxorubicin, which was associated with a further decrease in myocardial vitamin E level. As a result, the rats treated with both doxorubicin and the high fish oil diet showed the highest mortality rate and the lowest cardiac performance of all the experimental groups. CONCLUSIONS: Dietary fish oil may reduce antioxidant defences and accelerate susceptibility of the myocardium to lipid peroxidation in rats under doxorubicin treatment. This may partly explain why dietary fish oil does not prevent doxorubicin-induced cardiomyopathy.