Beneficial effect of a symbiotic preparation with S. boulardii lysate in mild stress-induced gut hyper-permeability.

Increased intestinal permeability has been advocated as one of the likely causes of various pathologies, such as allergies and metabolic or even cardiovascular disturbances. Thus, the aim of the present study was to test a symbiotic preparation containing microbial lysates (KC-1317, Named, Italy) against stress-induced derangement of gut mucosa permeability. Sprague Dawley rats were allocated into control (n=20) and stress (n=20) group. Stress was implemented by 1h of water avoidance stress daily for 10 days. Body weight, food and water intake and passage of stool pellet during stress session were recorded throughout the experiment. On the 11th day, fluorescent iso-thiocyanate dextran solution was injected into small intestinal loops. One hour after the injection, rats were sacrificed. Jejunum and ileum were taken for histopathology. Blood was collected from the abdominal aorta to measure intestinal permeability. In stress group, stool pellets during stress session was significantly higher than control group (p < 0.01). Villus height (p < 0.01), crypt depth (p < 0.01), number of goblet cells in villus (p < 0.01) and crypt (p < 0.05) decreased significantly in jejunum as compared to control. These phenomena were significantly prevented by KC-1317 (p < 0.05). Ileum also showed atrophy but villus height and the number of goblet cells in the villi did not significantly differ. Plasma-concentration of brain-gut peptides (substance P, thyrotropin-releasing hormone, cholecystokinin and motilin) were affected by stress (p < 0.001) and this effect did not change during supplementation with KC-1317. Polymorphonuclear neutrophil counting was significantly higher in stress group as compared to control (p < 0.01) but this phenomenon was abolished in the ileum (p < 0.01) or partly but significantly reduced by KC-1317 supplementation (p < 0.05). Accordingly, intestinal permeability was significantly enhanced in stress group as compared to control (p < 0.01) and prevented by KC-1317 (p < 0.01) in both intestinal segments examined. While confirming that chronic mild stress in rats compromises small intestinal morphology and permeability, we showed that a symbiotic microbial lysate can partly counteract this phenomenon.

Natriuretic peptides enhance the production of adiponectin in human adipocytes and in patients with chronic heart failure.

OBJECTIVES: We investigated the functional relationship between natriuretic peptides and adiponectin by performing both experimental and clinical studies. BACKGROUND: Natriuretic peptides are promising candidates for the treatment of congestive heart failure (CHF) because of their wide range of beneficial effects on the cardiovascular system. Adiponectin is a cytokine derived from adipose tissue with various cardiovascular-protective effects that has been reported to show a positive association with plasma brain natriuretic peptide (BNP) levels in patients with heart failure. METHODS: The expression of adiponectin messenger ribonucleic acid (mRNA) and its secretion were examined after atrial natriuretic peptide (ANP) or BNP was added to primary cultures of human adipocytes in the presence or absence of HS142-1 (a functional type A guanylyl cyclase receptor antagonist). Changes of the plasma adiponectin level were determined in 30 patients with CHF who were randomized to receive intravenous ANP (0.025 microg/kg/min human ANP for 3 days, n = 15) or saline (n = 15). RESULTS: Both ANP and BNP dose-dependently enhanced the expression of adiponectin mRNA and its secretion, whereas such enhancement was inhibited by pre-treatment with HS142-1. The plasma adiponectin level was increased at 4 days after administration of human ANP compared with the baseline value (from 6.56 +/- 0.40 microg/ml to 7.34 +/- 0.47 microg/ml, p < 0.05), whereas there was no change of adiponectin in the saline group (from 6.53 +/- 0.57 microg/ml to 6.55 +/- 0.56 microg/ml). CONCLUSIONS: Natriuretic peptides enhance adiponectin production by human adipocytes in vitro and even in patients with CHF, which might have a beneficial effect on cardiomyocytes in patients receiving recombinant natriuretic peptide therapy for heart failure.

Ablation of MEK kinase 1 suppresses intimal hyperplasia by impairing smooth muscle cell migration and urokinase plasminogen activator expression in a mouse blood-flow cessation model.

BACKGROUND: Migration, proliferation, and matrix-degrading protease expression of smooth muscle cells (SMCs) are major features of intimal hyperplasia after vascular injury. Although MEK kinase 1 (MEKK1) has been shown to regulate cell migration and urokinase plasminogen activator (uPA) expression, the precise role of MEKK1 in this process remains unknown. METHODS AND RESULTS: We triggered a vascular remodeling model by complete ligation of the right common carotid artery in wild-type (WT) and MEKK1-null (MEKK1-/-) mice. The intimal areas 28 days after ligation were significantly decreased in the ligated MEKK1-/- arteries compared with WT arteries (28+/-8 versus 65+/-17 microm2, P<0.05). There were no differences in the ratios of proliferating cell nuclear antigen (PCNA)-positive cells to total cells within the arterial wall between WT and MEKK1-/- arteries. Proliferation capacity also did not differ between WT and MEKK1-/- cultured aortic smooth muscle cells (AoSMCs). In contrast, the number of intimal PCNA-positive cells 7 days after ligation was significantly smaller in MEKK1-/- arteries. Three different migration assays revealed that migration and invasion of MEKK1-/- AoSMCs were markedly impaired. Addition of full-length MEKK1 restored the migration capacity of MEKK1-/- AoSMCs. The number of MEKK1-/- AoSMCs showing lamellipodia formation by epithelial growth factor was significantly smaller compared with those of WT SMCs. Furthermore, uPA expression after ligation was markedly decreased in MEKK1-/- arteries. CONCLUSIONS: MEKK1 is implicated in vascular remodeling after blood-flow cessation by regulating the migration and uPA expression of SMCs. MEKK1 is a potential target for drug development to prevent vascular remodeling.

Opening of Ca2+-activated K+ channels is involved in ischemic preconditioning in canine hearts.

Brief periods of ischemia that precede sustained ischemia can markedly reduce infarct size (IS), a phenomenon that is known as ischemic preconditioning (IP). Several investigators have shown that elevation of the intracellular Ca(2+) level ([Ca(2+)](i)) during the antecedent brief periods of ischemia triggers the cardioprotective mechanism of IP. Since opening of Ca(2+) activated K(+) (K(Ca)) channels is reported to be cardioprotective, we hypothesized that these channels may be involved in the cardioprotective mechanism of IP. In anesthetized open-chest dogs, myocardial ischemia/reperfusion injury was created by occlusion of the left anterior descending coronary artery (LAD) for 90 min followed by 6 h of reperfusion. First, we showed that the treatment with NS1619, a K(Ca) channel opener, reduced IS (IS in NS1619 group and control group, 19.8 +/- 5.5% vs. 45.4 +/- 3.5% of the area at risk, P < 0.05). Next, four cycles coronary occlusion for 5 min and reperfusion (IP) were performed before the 90-min occlusion with or without the infusion of potent K(Ca) channel inhibitors, iberiotoxin (IbTX) and charybdotoxin (ChTX). IP markedly reduced IS (IS in the IP group was 8.2 +/- 1.8%, P < 0.01 vs. control group). Infusion of either of K(Ca) channel blockers during IP blunted the IS-limiting effect of IP (IS in the IP + IbTX and IP + ChTX groups was 30.7 +/- 7.0% and 35.5 +/- 3.7%, respectively, P < 0.05, vs. IP group). However, the cardioprotective effect of IP was not blunted by the treatment with ChTX when treated only during reperfusion (14.0 +/- 4.1%). Thus, we conclude that the opening of K(Ca) channel is involved in early trigger phase of the molecular mechanism of IP.

Prolonged endoplasmic reticulum stress in hypertrophic and failing heart after aortic constriction: possible contribution of endoplasmic reticulum stress to cardiac myocyte apoptosis.

BACKGROUND: The endoplasmic reticulum (ER) is recognized as an organelle that participates in folding secretory and membrane proteins. The ER responds to stress by upregulating ER chaperones, but prolonged and/or excess ER stress leads to apoptosis. However, the potential role of ER stress in pathophysiological hearts remains unclear. METHODS AND RESULTS: Mice were subjected to transverse aortic constriction (TAC) or sham operation. Echocardiographic analysis demonstrated that mice 1 and 4 weeks after TAC had cardiac hypertrophy and failure, respectively. Cardiac expression of ER chaperones was significantly increased 1 and 4 weeks after TAC, indicating that pressure overload by TAC induced prolonged ER stress. In addition, the number of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive cells increased, and caspase-3 was cleaved in failing hearts. The antagonism of angiotensin II type 1 receptor prevented upregulation of ER chaperones and apoptosis in failing hearts. On the other hand, angiotensin II upregulated ER chaperones and induced apoptosis in cultured adult rat cardiac myocytes. We also investigated possible signaling pathways for ER-initiated apoptosis. The CHOP- (a transcription factor induced by ER stress), but not JNK- or caspase-12-, dependent pathway was activated in failing hearts by TAC. Pharmacological ER stress inducers upregulated ER chaperones and induced apoptosis in cultured cardiac myocytes. Finally, mRNA levels of ER chaperones were markedly increased in failing hearts of patients with elevated brain natriuretic peptide levels. CONCLUSIONS: These findings suggest that pressure overload by TAC induces prolonged ER stress, which may contribute to cardiac myocyte apoptosis during progression from cardiac hypertrophy to failure.