The dietary polyphenolic compound resveratrol, by activating the protein deacetylase enzyme silent information regulator 2/sirtuin 1 (SIRT1), prolongs life span in evolutionarily distant organisms and may mimic the cytoprotective effects of dietary restriction. The present study was designed to elucidate the effects of resveratrol on cigarette smoke-induced vascular oxidative stress and inflammation, which is a clinically highly relevant model of accelerated vascular aging. Cigarette smoke exposure of rats impaired the acetylcholine-induced relaxation of carotid arteries, which could be prevented by resveratrol treatment. Smoking and in vitro treatment with cigarette smoke extract (CSE) increased reactive oxygen species production in rat arteries and cultured coronary arterial endothelial cells (CAECs), respectively, which was attenuated by resveratrol treatment. The smoking-induced upregulation of inflammatory markers (ICAM-1, inducible nitric oxide synthase, IL-6, and TNF-alpha) in rat arteries was also abrogated by resveratrol treatment. Resveratrol also inhibited CSE-induced NF-kappaB activation and inflammatory gene expression in CAECs. In CAECs, the aforementioned protective effects of resveratrol were abolished by knockdown of SIRT1, whereas the overexpression of SIRT1 mimicked the effects of resveratrol. Resveratrol treatment of rats protected aortic endothelial cells against cigarette smoking-induced apoptotic cell death. Resveratrol also exerted antiapoptotic effects in CSE-treated CAECs, which could be abrogated by knockdown of SIRT1. Resveratrol treatment also attenuated CSE-induced DNA damage in CAECs (comet assay). Thus resveratrol and SIRT1 exert antioxidant, anti-inflammatory, and antiapoptotic effects, which protect the endothelial cells against the adverse effects of cigarette smoking-induced oxidative stress. The vasoprotective effects of resveratrol will likely contribute to its antiaging action in mammals and may be especially beneficial in pathophysiological conditions associated with accelerated vascular aging.

The germinal matrix of premature infants is selectively vulnerable to hemorrhage within the first 48 h of life. To assess the role of vascular immaturity in germinal matrix hemorrhage (GMH), we evaluated germinal matrix angiogenesis in human fetuses and premature infants, as well as in premature rabbit pups, and noted active vessel remodeling in all three. Vascular endothelial growth factor (VEGF), angiopoietin-2 and endothelial cell proliferation were present at consistently higher levels in the germinal matrix relative to the white matter anlagen and cortical mantle. On that basis, we asked whether prenatal treatment with either of two angiogenic inhibitors, the COX-2 inhibitor celecoxib, or the VEGFR2 inhibitor ZD6474, could suppress the incidence of GMH in premature rabbit pups. Celecoxib treatment decreased angiopoietin-2 and VEGF levels as well as germinal matrix endothelial proliferation. Furthermore, treatment with celecoxib or ZD6474 substantially decreased the incidence of GMH. Thus, by suppressing germinal matrix angiogenesis, prenatal celecoxib or ZD6474 treatment may be able to reduce both the incidence and severity of GMH in susceptible premature infants.

Neural stem and progenitor cells typically exhibit a density-dependent survival and expansion, such that critical densities are required below which clonogenic progenitors are lost. This suggests that short-range autocrine factors may be critical for progenitor cell maintenance. We report here that purines drive the expansion of ventricular zone neural stem and progenitor cells, and that purine receptor activation is required for progenitor cells to be maintained as such. Neural progenitors expressed P2Y purinergic receptors and mobilized intracellular calcium in response to agonist. Receptor antagonists suppressed proliferation and permitted differentiation into neurons and glia in vitro, while subsequent removal of purinergic inhibition restored progenitor cell expansion. Real-time bioluminescence imaging of extracellular ATP revealed that the source of extracellular nucleotides are the progenitor cells themselves, which appear to release ATP in episodic burst events. Enzyme histochemistry of the adult rat brain for ectonucleotidase activity revealed that NTDPase, which acts to degrade active ATP and thereby clears it from areas of active purinergic transmission, was selectively localized to the subventricular zone and the dentate gyrus, regions in which neuronal differentiation proceeds from the progenitor cell pool. These data suggest that purine nucleotides act as proliferation signals for neural progenitor cells, and thereby serve as negative regulators of terminal neuronal differentiation. As a result, progenitor cell-derived neurogenesis is thus associated with regions of both active purinergic signaling and modulation thereof.

Abstract-Proliferation of pulmonary arterial smooth muscle cells, endothelial dysfunction, oxidative stress, and inflammation promotes the development of pulmonary hypertension. Resveratrol is a polyphenolic compound that exerts antioxidant and anti-inflammatory protective effects in the systemic circulation, but its effects on pulmonary arteries remain poorly defined. The present study was undertaken to investigate the efficacy of resveratrol to prevent pulmonary hypertension. Rats injected with monocrotaline progressively developed pulmonary hypertension. Resveratrol treatment (25 mg/kg per day, PO, from day 1 postmonocrotaline) attenuated right ventricular systolic pressure and pulmonary arterial remodeling, decreased expression of inflammatory cytokines (tumor necrosis factor-␣, interleukin 1␤, interleukin 6, and platelet-derived growth factor-␣/␤), and limited leukocyte infiltration in the lung. Resveratrol also inhibited proliferation of pulmonary arterial smooth muscle cells. Treatment of rats with resveratrol increased expression of endothelial NO synthase, decreased oxidative stress, and improved endothelial function in small pulmonary arteries. Pulmonary hypertension was associated with an upregulation of NAD(P)H oxidase in small pulmonary arteries, which was significantly attenuated by resveratrol treatment. Our studies show that resveratrol exerts anti-inflammatory, antioxidant, and antiproliferative effects in the pulmonary arteries, which may contribute to the prevention of pulmonary hypertension. Key Words: pulmonary hypertension Ⅲ resveratrol Ⅲ oxidative stress Ⅲ endothelial dysfunction Ⅲ inflammation P ulmonary hypertension is a syndrome that encompasses several diseases, all of which have in common increased pulmonary artery pressures. Idiopathic ("primary") pulmonary hypertension is a rare disease caused by genetic defects in the bone morphogenetic protein signaling pathways. Common causes of "secondary" forms of pulmonary hypertension include the following: (1) pulmonary hypertension associated with chronic obstructive pulmonary disease; (2) pulmonary embolism; and (3) pressure/volume overload-related pulmonary hypertension. In addition, pulmonary hypertension often develops in patients with autoimmune diseases or as a severe adverse effect of anorectic drug treatment. Despite the diverse etiologic differences, many similarities in the pathological alterations in pulmonary arteries occur among the various forms of pulmonary hypertension, ie, vascular remodeling, including cellular proliferation in both the intima and media; endothelial dysfunction/increased vasoconstriction; and activation of inflammatory processes (eg, inflammatory cytokine expression and monocyte infiltration).Current therapies for chronic pulmonary hypertension are designed to reduce pulmonary arterial resistance by inducing vasodilation (eg, NO inhalation, stimulation of cGMP production by phosphodiesterase inhibitors, endothelin receptor antagonists, and prostacyclin analogs). These therapeutic approaches mainly provide ...

SummaryVascular aging is characterized by increased oxidative stress, impaired nitric oxide (NO) bioavailability and enhanced apoptotic cell death. The oxidative stress hypothesis of aging predicts that vascular cells of longlived species exhibit lower production of reactive oxygen species (ROS) and/or superior resistance to oxidative stress. We tested this hypothesis using two taxonomically related rodents, the white-footed mouse ( Peromyscus leucopus ) and the house mouse ( Mus musculus ), that show a more than twofold difference in maximum lifespan potential (MLSP = 8 and 3.5 years, respectively). We compared interspecies differences in endothelial superoxide ( ) and hydrogen peroxide (H 2 O 2 ) production, NAD(P)H oxidase activity, mitochondrial ROS generation, expression of pro-and antioxidant enzymes, NO production, and resistance to oxidative stress-induced apoptosis. In aortas of P. leucopus , NAD(P)H oxidase expression and activity, endothelial and H 2 O 2 production, and ROS generation by mitochondria were less than in mouse vessels. In P. leucopus , there was a more abundant expression of catalase, glutathione peroxidase 1 and hemeoxygenase-1, whereas expression of Cu/Zn-SOD and Mn-SOD was similar in both species. NO production and endothelial nitric oxide synthase expression was greater in P. leucopus . In mouse aortas, treatment with oxidized low-density lipoprotein (oxLDL) elicited substantial oxidative stress, endothelial dysfunction and endothelial apoptosis (assessed by TUNEL assay, DNA fragmentation and caspase 3 activity assays). According to our prediction, vessels of P. leucopus were more resistant to the proapoptotic effects of oxidative stressors (oxLDL and H 2 O 2 ). Primary fibroblasts from P. leucopus also exhibited less H 2 O 2 -induced DNA damage (comet assay) than mouse cells. Thus, increased lifespan potential in P. leucopus is associated with a decreased cellular ROS generation and increased oxidative stress resistance, which accords with the prediction of the oxidative stress hypothesis of aging.

Premature infants exhibit neurodevelopmental delay and reduced growth of the cerebral cortex. However, the underlying mechanisms have remained elusive. Therefore, we hypothesized that neurogenesis in the ventricular and subventricular zones of the cerebral cortex would continue in the third trimester of pregnancy, and that preterm birth would suppress neurogenesis. To test our hypotheses, we evaluated autopsy materials from human fetuses and preterm infants of 16–35 gestational weeks (gw). We noted that both cycling and non-cycling Sox2+ radial glial cells as well as Tbr2+ intermediate progenitors were abundant in human preterm infants until 28 gw. However, their densities consistently decreased from 16 through 28 gw. To determine the effect of premature birth on neurogenesis, we employed a rabbit model and compared preterm (E29, 3 days old) and term pups (E32, <2h age) at an equivalent post-conceptional age. Glutamatergic neurogenesis was suppressed in preterm rabbits, as indicated by reduced number of Tbr2+ intermediate progenitors and increased number of Sox2+ radial glia. Additionally, hypoxia inducible factor-1α, vascular endothelial growth factor, and erythropoietin were higher in term than preterm pups, reflecting the hypoxic intrauterine environment of just-born term pups. Proneural genes, including Pax6, Neurogenin-1 and -2, were higher in preterm rabbit pups compared to term pups. Importantly, neurogenesis and associated factors were restored in preterm pups by treatment with dimethyloxallyl glycine—a hypoxia mimetic agent. Hence, glutamatergic neurogenesis continues in the premature infants, preterm birth suppresses neurogenesis, and hypoxia-mimetic agents might restore neurogenesis, enhance cortical growth, and improve neurodevelopmental outcome of premature infants.

Preconditioning is an endogenous mechanism in which a nonlethal exposure increases cellular resistance to subsequent additional severe injury. Here we show that connexin 43 (Cx43) plays a key role in protection afforded by preconditioning. Cx43 null mice were insensitive to hypoxic preconditioning, whereas wild-type littermate mice exhibited a significant reduction in infarct volume after occlusion of the middle cerebral artery. In cultures, Cx43-deficient cells responded to preconditioning only after exogenous expression of Cx43, and protection was attenuated by small interference RNA or by channel blockers. Our observations indicate that preconditioning reduced degradation of Cx43, resulting in a marked increase in the number of plasma membrane Cx43 hemichannels. Consequently, efflux of ATP through hemichannels led to accumulation of its catabolic product adenosine, a potent neuroprotective agent. Thus, adaptive modulation of Cx43 can offset environmental stress by adenosine-mediated elevation of cellular resistance.

Germinal matrix (GM) is a richly vascularized collection of neuronal-glial precursor cells in the developing brain, which is selectively vulnerable to hemorrhage in premature infants. It has rapid angiogenesis associated with high levels of vascular endothelial growth factor (VEGF). Because pericytes provide structural stability to blood vessels, we asked whether pericytes were fewer in the GM than in the subjacent white matter and neocortex and, if so, whether angiogenic inhibition could increase the pericyte density in the GM. We found pericyte coverage and density less in the GM vasculature than in the cortex or white matter in human fetuses, premature infants, and premature rabbit pups. Notably, although VEGF suppression significantly enhanced pericyte coverage in the GM, it remained less than in other brain regions. Therefore, to further elucidate the basis of fewer pericytes in the GM vasculature, we examined expression of ligand-receptor systems responsible for pericyte recruitment. Transforming growth factor-␤1 (TGF-␤1) protein expression was lower, whereas sphingosine-1-phosphate1 (S1P1) and N-cadherin levels were higher in the GM than in the cortex or white matter. Low TGF-␤1 may be involved in promoting endothelial proliferation, whereas elevated S1P1 with N-cadherin may assist vascular maturation. Hence, a paucity of pericytes in the GM vasculature may contribute to its propensity to hemorrhage, and a lower expression of TGF-␤1 could be a basis of reduced pericyte density in its vasculature.