Endothelial dysfunction in cardiovascular and endocrine-metabolic diseases: an update

The endothelium plays a vital role in maintaining circulatory homeostasis by the release of relaxing and contracting factors. Any change in this balance may result in a process known as endothelial dysfunction that leads to impaired control of vascular tone and contributes to the pathogenesis of some cardiovascular and endocrine/metabolic diseases. Reduced endothelium-derived nitric oxide (NO) bioavailability and increased production of thromboxane A2, prostaglandin H2 and superoxide anion in conductance and resistance arteries are commonly associated with endothelial dysfunction in hypertensive, diabetic and obese animals, resulting in reduced endothelium-dependent vasodilatation and in increased vasoconstrictor responses. In addition, recent studies have demonstrated the role of enhanced overactivation ofβ-adrenergic receptors inducing vascular cytokine production and endothelial NO synthase (eNOS) uncoupling that seem to be the mechanisms underlying endothelial dysfunction in hypertension, heart failure and in endocrine-metabolic disorders. However, some adaptive mechanisms can occur in the initial stages of hypertension, such as increased NO production by eNOS. The present review focuses on the role of NO bioavailability, eNOS uncoupling, cyclooxygenase-derived products and pro-inflammatory factors on the endothelial dysfunction that occurs in hypertension, sympathetic hyperactivity, diabetes mellitus, and obesity. These are cardiovascular and endocrine-metabolic diseases of high incidence and mortality around the world, especially in developing countries and endothelial dysfunction contributes to triggering, maintenance and worsening of these pathological situations.

Mechanisms of endothelial dysfunction in obesity-associated hypertension

Obesity is strongly associated with high blood pressure, dyslipidemia, and type 2 diabetes. These conditions synergistically increase the risk of cardiovascular events. A number of central and peripheral abnormalities can explain the development or maintenance of high blood pressure in obesity. Of great interest is endothelial dysfunction, considered to be a primary risk factor in the development of hypertension. Additional mechanisms also related to endothelial dysfunction have been proposed to mediate the development of hypertension in obese individuals. These include: increase in both peripheral vasoconstriction and renal tubular sodium reabsorption, increased sympathetic activity and overactivation of both the renin-angiotensin system and the endocannabinoid system and insulin resistance. The discovery of new mechanisms regulating metabolic and vascular function and a better understanding of how vascular function can be influenced by these systems would facilitate the development of new therapies for treatment of obesity-associated hypertension.

Vascular dysfunction by myofibroblast activation in patients with idiopathic pulmonary fibrosis and prognostic significance

In this study, we demonstrated the importance of telomerase protein expression and determined the relationships among telomerase, endothelin-1 (ET-1) and myofibroblasts during early and late remodeling of parenchymal and vascular areas in usual interstitial pneumonia (UIP) using 27 surgical lung biopsies from patients with idiopathic pulmonary fibrosis (IPF). Telomerase+, myofibroblasts α-SMA+, smooth muscle cells caldesmon+, endothelium ET-1+ cellularity, and fibrosis severity were evaluated in 30 fields covering normal lung parenchyma, minimal fibrosis (fibroblastic foci), severe (mural) fibrosis, and vascular areas of UIP by the point-counting technique and a semiquantitative score. The impact of these markers was determined in pulmonary functional tests and follow-up until death from IPF. Telomerase and ET-1 expression was significantly increased in normal and vascular areas compared to areas of fibroblast foci. Telomerase and ET-1 expression was inversely correlated with minimal fibrosis in areas of fibroblast foci and directly associated with severe fibrosis in vascular areas. Telomerase activity in minimal fibrosis areas was directly associated with diffusing capacity of the lung for oxygen/alveolar volume and ET-1 expression and indirectly associated with diffusing capacity of the lungs for carbon monoxide and severe fibrosis in vascular areas. Cox proportional hazards regression revealed a low risk of death for females with minimal fibrosis displaying high telomerase and ET-1 expression in normal areas. Vascular dysfunction by telomerase/ET-1 expression was found earlier than vascular remodeling by myofibroblast activation in UIP with impact on IPF evolution, suggesting that strategies aimed at preventing the effect of these mediators may have a greater impact on patient outcome.

In vitro and in vivo studies of pirarubicin-loaded SWNT for the treatment of bladder cancer

Intravesical chemotherapy is an important part of the treatment for superficial bladder cancer. However, the response to it is limited and its side effects are extensive. Functional single-walled carbon nanotubes (SWNT) have shown promise for tumor-targeted accumulation and low toxicity. In the present study, we performed in vivo and in vitro investigations to determine whether SWNT-based drug delivery could induce high tumor depression in rat bladder cancer and could decrease the side effects of pirarubicin (tetrahydropyranyl-adriamycin, THP). We modified SWNT with phospholipid-branched polyethylene glycol and constructed an SWNT-THP conjugate via a cleavable ester bond. The cytotoxicity of SWNT-THP against the human bladder cancer cell line BIU-87 was evaluated in vitro. Rat bladder cancer in situ models constructed by N-methyl-N-nitrosourea intravesical installation (1 g/L, 2 mg/rat once every 2 weeks for 8 weeks) were used for in vivo evaluation of the cytotoxicity of SWNT and SWNT-THP. Specific side effects in the THP group including urinary frequency (N = 12), macroscopic hematuria (N = 1), and vomiting (N = 7) were identified; however, no side effects were observed with SWNT-THP treatment. Flow cytometry was used to assess the cytotoxicity in vitro and in vivo. Results showed that SWNT alone did not yield significant tumor depression compared to saline (1.74 ± 0.56 and 1.23 ± 0.42%) in vitro. SWNT-THP exhibited higher tumor depression than THP-saline in vitro (74.35 ± 2.56 and 51.24 ± 1.45%) and in vivo (52.46 ± 2.41 and 96.85 ± 0.85%). The present findings indicate that SWNT delivery of THP for the treatment of bladder cancer leads to minimal side effects without loss of therapeutic efficacy. Therefore, this nanotechnology may play a crucial role in the improvement of intravesical treatment of bladder cancer.

Effect of different durations of overdistention on rat bladder function and morphology

We investigated the contribution of the duration of overdistention (DOD) to rat bladder function and morphology and explored its possible molecular mechanisms. Bladder overdistention was induced in male Sprague-Dawley rats (200-250 g) by an infusion of saline. Forty rats were divided into 5 groups submitted to different DOD, i.e., 1, 2, 4, and 8 h, and control. Bladder function was evaluated by cystometry. Morphological changes were observed by light and transmission electron microscopy. Compared to control (44.567 ± 3.472 cmH2O), the maximum detrusor pressure of groups with 2-, 4- and 8-h DOD decreased significantly (means ± SEM): 32.774 ± 3.726, 31.321 ± 2.847, and 29.238 ± 3.724 cmH2O. With the increase of DOD, inflammatory infiltration and impairment of ultrastructure were more obvious in bladder tissue. Compared to control (1.90 ± 0.77), the apoptotic indexes of groups with 1-, 2-, 4-, and 8-h DOD increased significantly (6.47 ± 2.10, 10.66 ± 1.97, 13.91 ± 2.69, and 18.33 ± 3.28%). Compared to control (0.147 ± 0.031/0.234 ± 0.038 caspase 3/β-actin and Bax/Bcl-2 ratios), both caspase 3/β-actin and Bax/Bcl-2 ratios of 1-, 2-, 4-, and 8-h DOD increased significantly (0.292 ± 0.037/0.508 ± 0.174, 0.723 ± 0.173/1.745 ± 0.471, 1.104 ± 0.245/4.000 ± 1.048, and 1.345 ± 0.409/8.398 ± 3.332). DOD plays an important role in impairment of vesical function and structure. With DOD, pro-apoptotic factors increase and anti-apoptotic factors decrease, possibly contributing to the functional deterioration and morphological changes of the bladder.

Partial baroreceptor dysfunction and low plasma nitric oxide bioavailability as determinants of salt-sensitive hypertension: a reverse translational rat study

This study determined whether clinical salt-sensitive hypertension (cSSHT) results from the interaction between partial arterial baroreceptor impairment and a high-sodium (HNa) diet. In three series (S-I, S-II, S-III), mean arterial pressure (MAP) of conscious male Wistar ChR003 rats was measured once before (pdMAP) and twice after either sham (SHM) or bilateral aortic denervation (AD), following 7 days on a low-sodium (LNa) diet (LNaMAP) and then 21 days on a HNa diet (HNaMAP). The roles of plasma nitric oxide bioavailability (pNOB), renal medullary superoxide anion production (RMSAP), and mRNA expression of NAD(P)H oxidase and superoxide dismutase were also assessed. In SHM (n=11) and AD (n=15) groups of S-I, LNaMAP-pdMAP was 10.5±2.1 vs 23±2.1 mmHg (P<0.001), and the salt-sensitivity index (SSi; HNaMAP−LNaMAP) was 6.0±1.9 vs 12.7±1.9 mmHg (P=0.03), respectively. In the SHM group, all rats were normotensive, and 36% were salt sensitive (SSi≥10 mmHg), whereas in the AD group ∼50% showed cSSHT. A 45% reduction in pNOB (P≤0.004) was observed in both groups in dietary transit. RMSAP increased in the AD group on both diets but more so on the HNa diet (S-II, P<0.03) than on the LNa diet (S-III, P<0.04). MAP modeling in rats without a renal hypertensive genotype indicated that the AD*HNa diet interaction (P=0.008) increases the likelihood of developing cSSHT. Translationally, these findings help to explain why subjects with clinical salt-sensitive normotension may transition to cSSHT.

Morphometric evaluation of nitric oxide synthase isoforms and their cytokine regulators predict pulmonary dysfunction and survival in systemic sclerosis

Because histopathological changes in the lungs of patients with systemic sclerosis (SSc) are consistent with alveolar and vessel cell damage, we presume that this interaction can be characterized by analyzing the expression of proteins regulating nitric oxide (NO) and plasminogen activator inhibitor-1 (PAI-1) synthesis. To validate the importance of alveolar-vascular interactions and to explore the quantitative relationship between these factors and other clinical data, we studied these markers in 23 cases of SSc nonspecific interstitial pneumonia (SSc-NSIP). We used immunohistochemistry and morphometry to evaluate the amount of cells in alveolar septa and vessels staining for NO synthase (NOS) and PAI-1, and the outcomes of our study were cellular and fibrotic NSIP, pulmonary function tests, and survival time until death. General linear model analysis demonstrated that staining for septal inducible NOS (iNOS) related significantly to staining of septal cells for interleukin (IL)-4 and to septal IL-13. In univariate analysis, higher levels of septal and vascular cells staining for iNOS were associated with a smaller percentage of septal and vascular cells expressing fibroblast growth factor and myofibroblast proliferation, respectively. Multivariate Cox model analysis demonstrated that, after controlling for SSc-NSIP histological patterns, just three variables were significantly associated with survival time: septal iNOS (P=0.04), septal IL-13 (P=0.03), and septal basic fibroblast growth factor (bFGF; P=0.02). Augmented NOS, IL-13, and bFGF in SSc-NSIP histological patterns suggest a possible functional role for iNOS in SSc. In addition, the extent of iNOS, PAI-1, and IL-4 staining in alveolar septa and vessels provides a possible independent diagnostic measure for the degree of pulmonary dysfunction and fibrosis with an impact on the survival of patients with SSc.

Targeting PPM1D by lentivirus-mediated RNA interference inhibits the tumorigenicity of bladder cancer cells

Protein phosphatase magnesium/manganese-dependent 1D (PPM1D) is a p53-induced phosphatase that functions as a negative regulator of stress response pathways and has oncogenic properties. However, the functional role ofPPM1D in bladder cancer (BC) remains largely unknown. In the present study, lentivirus vectors carrying small hairpin RNA (shRNA) targeting PPM1D were used to explore the effects ofPPM1D knockdown on BC cell proliferation and tumorigenesis. shRNA-mediated knockdown of PPM1D significantly inhibited cell growth and colony forming ability in the BC cell lines 5637 and T24. Flow cytometric analysis showed that PPM1D silencing increased the proportion of cells in the G0/G1 phase. Downregulation of PPM1Dalso inhibited 5637 cell tumorigenicity in nude mice. The results of the present study suggest that PPM1D plays a potentially important role in BC tumorigenicity, and lentivirus-mediated delivery of shRNA againstPPM1D might be a promising therapeutic strategy for the treatment of BC.

Combined aliskiren and L-arginine treatment has antihypertensive effects and prevents vascular endothelial dysfunction in a model of renovascular hypertension

Angiotensin II is a key player in the pathogenesis of renovascular hypertension, a condition associated with endothelial dysfunction. We investigated aliskiren (ALSK) and L-arginine treatment both alone and in combination on blood pressure (BP), and vascular reactivity in aortic rings. Hypertension was induced in 40 male Wistar rats by clipping the left renal artery. Animals were divided into Sham, 2-kidney, 1-clip (2K1C) hypertension, 2K1C+ALSK (ALSK), 2K1C+L-arginine (L-arg), and 2K1C+ALSK+L-arginine (ALSK+L-arg) treatment groups. For 4 weeks, BP was monitored and endothelium-dependent and independent vasoconstriction and relaxation were assessed in aortic rings. ALSK+L-arg reduced BP and the contractile response to phenylephrine and improved acetylcholine relaxation. Endothelium removal and incubation with N-nitro-L-arginine methyl ester (L-NAME) increased the response to phenylephrine in all groups, but the effect was greater in the ALSK+L-arg group. Losartan reduced the contractile response in all groups, apocynin reduced the contractile response in the 2K1C, ALSK and ALSK+L-arg groups, and incubation with superoxide dismutase reduced the phenylephrine response in the 2K1C and ALSK groups. eNOS expression increased in the 2K1C and L-arg groups, and iNOS was increased significantly only in the 2K1C group compared with other groups. AT1 expression increased in the 2K1C compared with the Sham, ALSK and ALSK+L-arg groups, AT2 expression increased in the ALSK+L-arg group compared with the Sham and L-arg groups, and gp91phox decreased in the ALSK+L-arg group compared with the 2K1C and ALSK groups. In conclusion, combined ALSK+L-arg was effective in reducing BP and preventing endothelial dysfunction in aortic rings of 2K1C hypertensive rats. The responsible mechanisms appear to be related to the modulation of the local renin-angiotensin system, which is associated with a reduction in endothelial oxidative stress.

Overexpression of myeloid differentiation protein 88 in mice induces mild cardiac dysfunction, but no deficit in heart morphology

Cardiac remodeling involves changes in heart shape, size, structure, and function after injury to the myocardium. The proinflammatory adaptor protein myeloid differentiation protein 88 (MyD88) contributes to cardiac remodeling. To investigate whether excessive MyD88 levels initiate spontaneous cardiac remodeling at the whole-organism level, we generated a transgenic MyD88 mouse model with a cardiac-specific promoter. MyD88 mice (male, 20-30 g, n=∼80) were born at the expected Mendelian ratio and demonstrated similar morphology of the heart and cardiomyocytes with that of wild-type controls. Although heart weight was unaffected, cardiac contractility of MyD88 hearts was mildly reduced, as shown by echocardiographic examination, compared with wild-type controls. Moreover, the cardiac dysfunction phenotype was associated with elevation of ANF and BNP expression. Collectively, our data provide novel evidence of the critical role of balanced MyD88 signaling in maintaining physiological function in the adult heart.

Restoration of sensory dysfunction following peripheral nerve injury by the polysaccharide from culinary and medicinal mushroom, Hericium erinaceus (Bull.: Fr.) Pers. through its neuroregenerative action

Abstract Peripheral nerves have the unique capability to regenerate after injury. Insights into regeneration of peripheral nerves after injury may have implications for neurodegenerative diseases of the nervous system. We investigated the ability of polysaccharide from Hericium erinaceus mushroom in the treatment of nerve injury following peroneal nerve crush in Sprague-Dawley rats by daily oral administration. In sensory functional recovery test, the time taken for the rats to withdraw its hind limb from contact with the hot plate was measured. The test revealed acceleration of sensory recovery in the polysaccharide group compared to negative controls. Further, peripheral nerve injury leads to changes at the remotely located DRG containing cell bodies of sensory neurons. Immunofluorescence studies showed that Akt and p38 MAPK were expressed in DRG and strongly upregulated in polysaccharide group after peripheral nerve injury. The intensity of endothelial cells antigen-1 that recognized endothelial cells in the blood vessels of distal segments in crushed nerves was significantly higher in the treated groups than in the negative control group. Our findings suggest that H. erinaceus is capable of accelerating sensory functional recovery after peripheral nerve injury and the effect involves the activation of protein kinase signaling pathways and restoration of blood-nerve barrier.

Erectile dysfunction in cardiovascular risk population

The inability to achieve and to maintain erection, erectile dysfunction, is a bothersome symptom of elderly men. Moreover, there is a high comorbidity between cardiovascular diseases and erectile dysfunction. However, very little is known concerning the risk factors of ED in apparently healthy men without comorbidities affecting the arteries. A cross-sectional population survey was conducted from August 2005 to September 2007 in two rural towns of Harjavalta and Kokemäki in Finland. Excluding those with previously diagnosed cardiovascular diseases, diabetes or chronic kidney disease, every community-dwelling inhabitant was invited to take part in the survey. Of the 2939 45- to 70-year-old men invited, 2049 responded. Selecting those at risk for cardiovascular diseases, 1000 eligible men were examined. According to the International Index of Erectile Function short form 57% of the studied men reported erectile dysfunction. Increasing age, smoking, depressive symptoms, decreasing pulmonary function, sedentary lifestyle, non-marital status and low education level were associated with increasing risk of erectile dysfunction. However, hypertension, diabetes, obesity, hypercholesterolemia were not associated with erectile dysfunction, although these associations have been described in numerous previous studies. Moreover, erectile dysfunction was not associated with increasing risk of pre-diabetes. In apparently healthy men, increasing age, smoking, depressive symptoms, decreasing pulmonary function, sedentary lifestyle, non-marital status, low education level but not hypertension, obesity, hypercholesterolemia, diabetes or pre-diabetes were associated with increasing risk of erectile dysfunction.

The social consequences of mild head injury and executive dysfunction /

Mild head injury (MHI) is a serious cause of neurological impairment as is evident by the substantial percentage (15%) of individuals who remain symptomatic at least 1-year following "mild" head trauma. However, there is a paucity of research investigating the social consequences following a MHI. The first objective of this study was to examine whether measures of executive functioning were predictive of specific forms of antisocial behaviour, such as reactive aggression, impulsive antisocial behaviour, behavioural disinhibition, and deficits in social awareness after controlling for the variance accounted for by sex differences. The second objective was to investigate whether a history of MHI was predictive of these same social consequences after controlling for both sex differences and executive functioning. Ninety university students participated in neuropsychological testing and filled out self-report questionnaires. Fifty-two percent of the sample self-reported experiencing a MHI. As expected, men were more reactively aggressive and antisocial than women. Furthermore, executive dysfunction predicted reactive aggression and impulsive antisocial behaviour after controlling for sex differences. Finally, as expected, MHI status predicted reactive aggression, impulsive antisocial behaviour, and behavioural disinhibition after controlling for sex and executive fimctioning. MHI status and executive functioning did not predict social awareness or sensitivity to reward or punishment. These results suggest that incurring a MHI has serious social consequences that mirror the neurobehavioural profile following severe cases of brain injury. Therefore, the social sequelae after MHI imply a continuum of behavioural deficits between MHI and more severe forms of brain injury.

Intrahemispheric dysfunction in primary motor cortex without corpus callosum: a transcranial magnetic stimulation study

Affiliation: Département de Psychologie, Université de Montréal

Manganese deposition in basal ganglia structures results from both portal-systemic shunting and liver dysfunction.

BACKGROUND & AIMS: Manganese (Mn) deposition could be responsible for the T(1)-weighted magnetic resonance signal hyperintensities observed in cirrhotic patients. These experiments were designed to assess the regional specificity of the Mn increases as well as their relationship to portal-systemic shunting or hepatobiliary dysfunction. METHODS: Mn concentrations were measured in (1) brain samples from basal ganglia structures (pallidum, putamen, caudate nucleus) and cerebral cortical structures (frontal, occipital cortex) obtained at autopsy from 12 cirrhotic patients who died in hepatic coma and from 12 matched controls; and from (2) brain samples (caudate/putamen, globus pallidus, frontal cortex) from groups (n = 8) of rats either with end-to-side portacaval anastomosis, with biliary cirrhosis, or with fulminant hepatic failure as well as from sham-operated and normal rats. RESULTS: Mn content was significantly increased in frontal cortex (by 38\%), occipital cortex (by 55\%), pallidum (by 186\%), putamen (by 66\%), and caudate (by 54\%) of cirrhotic patients compared with controls. Brain Mn content did not correlate with patient age, etiology of cirrhosis, or history of chronic hepatic encephalopathy. In cirrhotic and portacaval-shunted rats, Mn content was increased in pallidum (by 27\% and 57\%, respectively) and in caudate/putamen (by 57\% and 67\%, respectively) compared with control groups. Mn concentration in pallidum was significantly higher in portacaval-shunted rats than in cirrhotic rats. No significant changes in brain Mn concentrations were observed in rats with acute liver failure. CONCLUSIONS: These findings suggest that brain Mn deposition results both from portal-systemic shunting and from liver dysfunction.