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Protective mechanisms of resveratrol against ischemia-reperfusion-induced damage in hearts obtained from Zucker obese rats: the role of GLUT-4 and endothelin. Am J Physiol Heart Circ Physiol 294: H859-H866, 2008. First published December 7, 2007 doi:10.1152/ajpheart.01048.2007.-The resveratrol-induced cardiac protection was studied in Zucker obese rats. Rats were divided into five groups: group 1, lean control; group 2, obese control (OC); group 3, obese rats treated orally with 5 mg ⅐ kg Ϫ1 ⅐ day Ϫ1 of resveratrol (OR) for 2 wk; group 4, obese rats received 10% glucose solution ad libitum for 3 wk (OG); and group 5, obese rats received 10% glucose for 3 wk and resveratrol (OGR) during the 2nd and 3rd wk. Body weight, serum glucose, and insulin were measured, and then hearts were isolated and subjected to 30 min of ischemia followed by 120 min of reperfusion. Heart rate, coronary flow, aortic flow, developed pressure, the incidence of reperfusioninduced ventricular fibrillation, and infarct size were measured. Resveratrol reduced body weight and serum glucose in the OR compared with the OC values (414 Ϯ 10 g and 7.08 Ϯ 0.41 mmol/l, respectively, to 378 Ϯ 12 g and 6.11 Ϯ 0.44 mmol/l), but insulin levels were unchanged. The same results were obtained for the OG vs. OGR group. Resveratrol improved postischemic cardiac function in the presence or absence of glucose intake compared with the resveratrolfree group. The incidence of ventricular fibrillation and infarct size was reduced by 83 and 20% in the OR group, and 67 and 16% in the OGR group, compared with the OC and OG groups, respectively. Resveratrol increased GLUT-4 expression and reduced endothelin expression and cardiac apoptosis in ischemic-reperfused hearts in the presence or absence of glucose intake. Thus the protective effect of resveratrol could be related to its direct effects on the heart. heart; ischemia-reperfusion; diabetes; rat IN THE PAST THREE DECADES, an explosive increase in the number of people diagnosed with diabetes was seen worldwide (7, 48).

Cardioprotective mechanisms of Prunus cerasus (sour cherry) seed extract against ischemia-reperfusion-induced damage in isolated rat hearts. Am J Physiol Heart Circ Physiol 291: H1329 -H1336, 2006. First published April 14, 2006 doi:10.1152/ajpheart.01243.2005The effects of kernel extract obtained from sour cherry (Prunus cerasus) seed on the postischemic cardiac recovery were studied in isolated working rat hearts. Rats were treated with various daily doses of the extract for 14 days, and hearts were then isolated and subjected to 30 min of global ischemia followed by 120 min of reperfusion. The incidence of ventricular fibrillation (VF) and tachycardia (VT) fell from their control values of 92% and 100% to 50% (not significant) and 58% (not significant), 17% (P Ͻ 0.05), and 25% (P Ͻ 0.05) with the doses of 10 mg/kg and 30 mg/kg of the extract, respectively. Lower concentrations of the extract (1 and 5 mg/kg) failed to significantly reduce the incidence of VF and VT during reperfusion. Sour cherry seed kernel extract (10 and 30 mg/kg) significantly improved the postischemic recovery of cardiac function (coronary flow, aortic flow, and left ventricular developed pressure) during reperfusion. We have also demonstrated that the extract-induced protection in cardiac function significantly reflected in a reduction of infarct size. Immunohistochemistry indicates that a reduction in caspase-3 activity and apoptotic cells by the extract, beside other potential action mechanisms of proanthocyanidin, trans-resveratrol, and flavonoid components of the extract, could be responsible for the cardioprotection in ischemic-reperfused myocardium.

A recent study from our laboratory indicated the cardioprotective ability of the tocotrienolrich fraction (TRF) from red palm oil. The present study compared cardioprotective abilities of different isomers of tocotrienol against TRF as recently tocotrienol has been found to function as a potent neuroprotective agent against stroke. Rats were randomly assigned to one of the following groups: animals were given, by gavage, either 0.35%, 1%, or 3.5% TRF for two different periods of time (2 or 4 wk) or 0.03, 0.3, and 3 mg/kg body wt of one of the isomers of tocotrienol (␣, ␥, or ␦) for 4 wk; control animals were given, by gavage, vehicle only. After 2 or 4 wk, rats were killed, and their hearts were then subjected to 30 min of global ischemia followed by 2 h of reperfusion. Dose-response and time-response experiments revealed that the optimal concentration for TRF was 3.5% TRF and 0.3 mg/kg body wt of tocotrienol given for 4 wk. TRF as well as all the isomers of tocotrienol used in our study provided cardioprotection, as evidenced by their ability to improve postischemic ventricular function and reduce myocardial infarct size. The ␥-isoform of tocotrienol was the most cardioprotective of all the isomers followed by the ␣-and ␦-isoforms. The molecular mechanisms of cardioprotection afforded by tocotrienol isoforms were probed by evaluating their respective abilities to stabilize the proteasome, allowing it to maintain a balance between prodeath and prosurvival signals. Our results demonstrated that tocotrienol isoforms reduced c-Src but increased the phosphorylation of Akt, thus generating a survival signal.

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Jeong JK, Szabo G, Raso GM, Meli R, Diano S. Deletion of prolyl carboxypeptidase attenuates the metabolic effects of diet-induced obesity. Am J Physiol Endocrinol Metab 302: E1502-E1510, 2012. First published March 27, 2012 doi:10.1152/ajpendo.00544.2011.-␣-Melanocyte-stimulating hormone (␣-MSH) is a critical regulator of energy metabolism. Prolyl carboxypeptidase (PRCP) is an enzyme responsible for its degradation and inactivation. PRCP-null mice (PRCP gt/gt ) showed elevated levels of brain ␣-MSH, reduced food intake, and a leaner phenotype compared with wild-type controls. In addition, they were protected against diet-induced obesity. Here, we show that PRCP gt/gt animals have improved metabolic parameters compared with wild-type controls under a standard chow diet (SD) as well as on a high-fat diet (HFD). Similarly to when they are exposed to SD, PRCP gt/gt mice exposed to HFD for 13 wk showed a leaner phenotype due to decreased fat mass, increased energy expenditure, and locomotor activity. They also showed improved insulin sensitivity and glucose tolerance compared with WT controls and a significant reduction in fasting glucose levels. These improvements occured before changes in body weight and composition were evident, suggesting that the beneficial effect of PRCP ablation is independent of the adiposity levels. In support of a reduced gluconeogenesis, liver PEPCK and G-6-Pase mRNA levels were reduced significantly in PRCP gt/gt compared with WT mice. A significant decrease in liver weight and hepatic triglycerides were also observed in PRCP gt/gt compared with WT mice. Altogether, our data suggest that PRCP is an important regulator of energy and glucose homeostasis since its deletion significantly improves metabolic parameters in mice exposed to both SD and HFD.␣-melanocyte-stimulating hormone; energy metabolism; insulin sensitivity; glucose metabolism A PRECISE CONTROL OF CALORIC INTAKE and energy expenditure is fundamental for the balance of energy homeostasis. In the mammalian brain, a product of the proopiomelanocortin (POMC) gene, ␣-melanocyte-stimulating hormone (␣-MSH) plays a central role in detecting, integrating, and responding to a range of central and peripheral inputs relating to energy metabolism (1,4,13,14,20). The use of genetically altered mouse models has shown the importance of ␣-MSH in the regulation of a broad range of metabolic parameters (9, 17). Mice with ablation of the POMC gene are obese, whereas mice overexpressing ␣-MSH in the brain showed protection against diet-induced obesity with improved glucose homeostasis.We have reported recently a molecular mechanism that is responsible for the inactivation and degradation of ␣-MSH (21). Prolylcarboxypeptidase (PRCP) is a serine protease that cleaves the last amino acid at the COOH terminus of small peptides if proline is the penultimate amino acid. We have shown previously that PRCP is expressed in the lateral hypothalamus, where PRCP-expressing neurons target with their axons the paraventricular nucleus of the hypothalamus, a sit...

Hypothalamic α-melanocyte-stimulating hormone (α-MSH) plays a central role in regulating energy uptake and expenditure. Prolyl carboxypeptidase (PRCP), a protease expressed in the hypothalamus, is responsible for the degradation of α-MSH. PRCP null animals (PRCP(gt/gt) mice) display elevated α-MSH in the hypothalamus, lower body weight, and are protected from diet induced obesity. Here, we report that PRCP(gt/gt) mice have a significant decrease in fat mass, although an increase in lean mass was also observed. In agreement with low fat accumulation, reduced leptin levels were found. Consistent with the effect of α-MSH on energy metabolism, PRCP(gt/gt) mice had increased energy expenditure with elevated circulating thyroid hormone levels and brown adipose tissue uncoupling protein 1 mRNA levels compared with control mice when exposed to regular diet. TRH mRNA levels in the PVN were significantly higher in fed PRCP(gt/gt) animals compared with fed wild-type controls. Fasting significantly decreased TRH mRNA levels in both PRCP(gt/gt) and wild-type (WT) mice. However, TRH mRNA levels in fasted PRCP(gt/gt) animals were significantly higher than those of fasted WT mice. Refeeding analysis after fasting showed a reduced food intake in PRCP(gt/gt) compared with WT mice. Finally, TRH mRNA levels in T(3)-treated hypothyroid PRCP(gt/gt) mice showed a non significant reduction compared with those of hypothyroid PRCP(gt/gt) mice, supporting the impairment of the hypothalamo-pituitary-thyroid axis in PRCP(gt/gt) mice. All together, these data confirm that PRCP plays a role in the regulation of energy metabolism.

When human recombinant interferon-alpha 2 diluted in saline was injected s.c. into rabbits, the total amount recovered in thoracic lymph was less than 0.4%. Recoveries increased from 2- to 8-fold if interferon was injected in 4% albumin or with hyaluronidase, respectively. Albumin added to interferon acts as an interstitial fluid expander, thus favoring interferon absorption through lymphatics rather than blood capillaries. This strategy may increase the therapeutic index of interferon.