Abstract P2005: Antioxidant Resveratrol Attenuates Cardiac Fibrosis and Reduces Matrix Metalloproteinase-2 Activity in Heart Failure Rats

Increased reactive oxygen species activate matrix metalloproteinases (MMP) playing a critical role in cardiovascular remodeling after myocardial infarction (MI). We evaluated the antioxidant effect of resveratrol (RESV) on cardiac remodeling and MMP-2 activity in heart failure (HF) rats. Wistar rats were divided into the following groups: Control; Control+RESV; HF; HF+RESV (10mg/kg/day, p.o., 4 wk). The MI was elicited by ligation of the coronary artery. After four weeks, the animals were anesthetized to evaluate the cardiac function and to collect the hearts and blood samples. Heart weight/body weight (HW/BW, mg/g) ratio and the infarct size were calculated. Histological assessment of the left ventricle was carried out with hematoxylin/eosin, and fibrosis was quantified with Masson trichrome-staining. Cardiac and plasma MMP-2 activities were determined by gel zymography. The oxidative stress was assessed measuring the thiobarbituric acid reactive substances (TBARS) from plasma. HF and HF+RESV showed similar infarct size. The HW/BW ratio increased (3.7±0.2 vs 3.8±0.2 vs 3.0±0.05). RESV improved the maximal slope of the systolic increment of left ventricular pressure in HF animals (9004±1120 vs 5849±595 vs 7181±533 mmHg/s) and reduced the end diastolic pressure (4±1 vs 18±4 vs 7±1 mmHg). HF increased TBARS, whereas RESV produced an antioxidant effect in HF+RESV group (11.2±0.9 vs 21.7±3 vs 8.2±1.4 μmol/L). HF augmented cardiac fibrosis (30,8±1,3 vs 8,8±0,5%) and myocyte hypertrophy (12,2±0,7 vs 8,8±0,3μm). RESV reduced collagen deposition in HF hearts (22,7±1,9%), but did not reduce the myocyte hypertrophy (11,7±0,6 μm). Cardiac and plasma MMP-2 activity were higher in HF animals (plasma: 1344±39 vs. 1164±47; heart: 536±54 vs. 262±18). RESV decreased plasma MMP-2 activity in control (992±27) and HF animals (1200±49) and reduced cardiac MMP-2 activity only in HF+RESV group (426±42). In conclusion, the antioxidant effect of RESV improved cardiac function and fibrosis and reduced MMP-2 levels in the heart and plasma from HF rats.

Factors associated with spontaneous HBsAg clearance in chronic hepatitis B patients followed at a university hospital

INTRODUCTION

Few studies have evaluated the factors involved in the spontaneous HBsAg seroclearance in patients with chronic hepatitis B (HBV) followed up on a long-term basis from areas with a low prevalence of HBV infection. We aimed to determine the rate of spontaneous HBsAg seroclearance and the factors related to it in patients with chronic HBV infection followed up at the Hepatitis Outpatient Clinic of HCFMRP from 1992-2008.

MATERIALS AND METHODS

A total of 548 patients with chronic HBV infection (366 with chronic hepatitis B and 182 inactive carriers) were followed for 15 years and 9 months with an annual measurement of HBV-DNA, ALT, AST and GGT (average of 4 annual determinations) and serology (HBsAg, HBeAg, Anti-HBeAg and Anti-HBsAg).

RESULTS

Spontaneous HBsAg seroclearance occurred in 40 patients (7.3%) with a mean age of 46.0 ± 14.4 years, corresponding to an annual rate of 0.7%.The factors related to spontaneous HBsAg seroclearance were inactive carrier status (67.5 vs. 32.5%, p = 0.000191) and age of more than 40 years (p = 0.0007). There was no difference in the rate of spontaneous HBsAg seroclearance when comparing males and females (p = 0.383). Patients with spontaneous HBsAg seroclearance did not progress to more severe forms of the disease during follow-up.

CONCLUSION

Spontaneous HBsAg seroclearance has a favorable long-term prognosis in patients with chronic HBV infection. HBsAg seroclearance occurred at rates compatible with low prevalence areas and was associated with low serum HBV-DNA levels and an age older than 40 years.

Rosmarinic Acid Suppresses Subconjunctival Neovascularization in Experimental Glaucoma Surgery

PURPOSE

Excessive subconjunctival scarring is associated with increased angiogenesis and leads to filtration failure in glaucoma surgery. In this study, we describe that rosmarinic acid (RA) has anti-angiogenic activity during wound healing in a rabbit model of glaucoma surgery.

METHODS

Forty New Zealand rabbits underwent an experimental trabeculectomy and were randomly allocated into two treatment groups: RA group - treated with subconjunctival injections of 0.1 ml RA (15 mg/ml; n = 20) - and control group - treated with subconjunctival injections of 0.1 ml balanced salt solution (n = 20). The in vivo effect of RA was investigated after 5 and 15 d by measuring the intraocular pressure (IOP; with Tonopen) and bleb area and vascularity (using the Moorfields Bleb Grading System). Vascularization was also studied by counting histological blood vessels and by immunohistochemistry of vascular endothelial growth factor (VEGF) at the surgical site and by quantification of vessels in chicken's chorioallantoic membrane (CAM), treated with AR 500 μg/ml for 48 h.

RESULTS

On the fifth day, eyes of RA group displayed higher bleb area (3.6 ± 0.2 versus 1.8 ± 0.2; p = 0.004) and lower vascularity (3.0 ± 0.5 versus 4.0 ± 0.4; p = 0.009) than controls; however, difference in IOP reduction was not significant (-1.4 ± 0.3 versus -0.8 ± 0.3 mmHg; p = 0.226). Proportion of vessels/field (4.6 ± 0.5 versus 10.4 ± 0.9; p = 0.008) and VEGF immunostaining (15,347 ± 3788 versus 31,043 ± 3230; p = 0.019) also declined with RA treatment. However, at the 15th day, none of the parameters were different between the groups, except for vessels/field proportion (5.4 ± 1.0 versus 10.6 ± 1.6; p = 0.035). CAM exposed to AR inhibited vascularization (-45.67 ± 4.74%; p < 0.001).

CONCLUSION

These data indicate RA has a short-term anti-angiogenic effect and could be a potential modulator of neovascularization during subconjunctival healing at glaucoma filtration surgical sites.

Altered expression of noncanonical Wnt pathway genes in paediatric and adult adrenocortical tumours

CONTEXT

The role of planar cell polarity (Wnt/PCP) and calcium-dependent (Wnt/Ca) noncanonical Wnt pathways in adrenocortical tumours (ACTs) is unknown.

OBJECTIVES

To investigate the gene expression of Wnt/PCP and Wnt/Ca pathways and its association with TP53 p.R337H and CTNNB1 mutations in paediatric and adult ACTs and to correlate these findings with clinical outcome.

PATIENTS

Expression of noncanonical Wnt-related genes was evaluated in 91 ACTs (66 children and 25 adults) by qPCR and the expression of beta-catenin, P53 and protein effectors of Wnt/Ca (NFAT) and Wnt/PCP (JNK) by immunohistochemistry. TP53 and CTNNB1 genes were sequenced.

RESULTS

TP53 p.R337H mutation frequency was higher in children (86% vs 28%), while CTNNB1 mutation was higher in adults (32% vs 6%). Mortality was higher in adults harbouring TP53 p.R337H and in children with CTNNB1 mutations. Overexpression of WNT5A, Wnt/Ca ligand, was observed in children and adults. Overexpression of MAPK8 and underexpression of PRICKLE, Wnt/PCP mediators, were observed in paediatric but not in adult cases. Cytoplasmic/nuclear beta-catenin and P53 accumulation was observed in the majority of paediatric and adult ACTs as well as NFAT and JNK. Overexpression of MAPK8 and underexpression of PRICKLE were associated with mortality in children, while overexpression of WNT5A and underexpression of PRICKLE were associated with mortality in adults.

CONCLUSIONS

In our study, TP53 p.R337H and CTNNB1 mutations correlated with poor prognosis in adults and children, respectively. We demonstrate, for the first time, the activation of Wnt/PCP and Wnt/Ca noncanonical pathway genes, and their association with poor outcome in children and adults, suggesting their putative involvement in ACTs aggressiveness.

Sonic hedgehog signaling is active in human adrenal cortex development and deregulated in adrenocortical tumors

BACKGROUND

The sonic hedgehog (SHH) pathway plays a key role in rodent adrenal cortex development and is involved in tumorigenesis in several human tissues, but data in human adrenal glands are limited.

OBJECTIVES

The objectives of the study were to analyze the involvement of the SHH pathway in human adrenal development and tumorigenesis and the effects of SHH inhibition on an adrenocortical tumor (ACT) cell line.

PATIENTS AND METHODS

Expression of SHH pathway components was evaluated by immunohistochemistry in 51 normal adrenals (33 fetal) and 34 ACTs (23 pediatric) and by quantitative PCR in 81 ACTs (61 pediatric) and 19 controls (10 pediatric). The effects of SHH pathway inhibition on gene expression and cell viability in the NCI-H295A adrenocortical tumor cell line after cyclopamine treatment were analyzed.

RESULTS

SHH pathway proteins were present in fetal and postnatal normal adrenals and showed distinct patterns of spatiotemporal expression throughout development. Adult adrenocortical carcinomas presented with higher expression of PTCH1, SMO, GLI3, and SUFU compared with normal adult adrenal cortices. Conversely, pediatric ACTs showed lower mRNA expression of SHH, PTCH1, SMO, GLI1, and GLI3 compared with normal pediatric adrenal cortices. In vitro treatment with cyclopamine resulted in decreased GLI3, SFRP1, and CTNNB1 mRNA expression and β-catenin staining as well as decreased cell viability.

CONCLUSIONS

The SHH pathway is active in human fetal and postnatal adrenals, up-regulated in adult adrenocortical carcinomas, and down-regulated in pediatric ACTs. SHH pathway antagonism impaired cell viability. The SHH pathway is deregulated in ACTs and might provide a new target therapy to be explored.

Cigarette smoking exacerbates nonalcoholic fatty liver disease in obese rats

The prevalence of cigarette smoking (CS) is increased among obese subjects, who are susceptible to develop nonalcoholic fatty liver disease (NAFLD). We investigated the hepatic effects of CS in control and obese rats. Control and obese Zucker rats were divided into smokers and nonsmokers (n = 12 per group). Smoker rats were exposed to 2 cigarettes/day, 5 days/week for 4 weeks. The effects of CS were assessed by biochemical analysis, hepatic histological examination, immunohistochemistry, and gene expression analysis. Phosphorylation of AKT and extracellular signal-regulated kinase (ERK) and quantification of carbonylated proteins were assessed by western blotting. As expected, obese rats showed hypercholesterolemia, insulin resistance, and histological features of NAFLD. Smoking did not modify the lipidic or glucidic serum profiles. Smoking increased alanine aminotransferase serum levels and the degree of liver injury in obese rats, whereas it only induced minor changes in control rats. Importantly, CS increased the histological severity of NAFLD in obese rats. We also explored the potential mechanisms involved in the deleterious effects of CS. Smoking increased the degree of oxidative stress and hepatocellular apoptosis in obese rats, but not in controls. Similarly, smoking increased the hepatic expression of tissue inhibitor of metalloproteinase-1 and procollagen-alpha2(I) in obese rats, but not in controls. Finally, smoking regulated ERK and AKT phosphorylation. The deleterious effects of CS were not observed after a short exposure (5 days).

CONCLUSION

CS causes oxidative stress and worsens the severity of NAFLD in obese rats. Further studies should assess whether this finding also occurs in patients with obesity and NAFLD.

Ghrelin attenuates hepatocellular injury and liver fibrogenesis in rodents and influences fibrosis progression in humans

There are no effective antifibrotic therapies for patients with liver diseases. We performed an experimental and translational study to investigate whether ghrelin, an orexigenic hormone with pleiotropic properties, modulates liver fibrogenesis. Recombinant ghrelin was administered to rats with chronic (bile duct ligation) and acute (carbon tetrachloride) liver injury. Hepatic gene expression was analyzed by way of microarray analysis and quantitative polymerase chain reaction. The hepatic response to chronic injury was also evaluated in wild-type and ghrelin-deficient mice. Primary human hepatic stellate cells were used to study the effects of ghrelin in vitro. Ghrelin hepatic gene expression and serum levels were assessed in patients with chronic liver diseases. Ghrelin gene polymorphisms were analyzed in patients with chronic hepatitis C. Recombinant ghrelin treatment reduced the fibrogenic response, decreased liver injury and myofibroblast accumulation, and attenuated the altered gene expression profile in bile duct-ligated rats. Moreover, ghrelin reduced the fibrogenic properties of hepatic stellate cells. Ghrelin also protected rats from acute liver injury and reduced the extent of oxidative stress and inflammation. Ghrelin-deficient mice developed exacerbated hepatic fibrosis and liver damage after chronic injury. In patients with chronic liver diseases, ghrelin serum levels decreased in those with advanced fibrosis, and ghrelin gene hepatic expression correlated with expression of fibrogenic genes. In patients with chronic hepatitis C, polymorphisms of the ghrelin gene (-994CT and -604GA) influenced the progression of liver fibrosis.

CONCLUSION

Ghrelin exerts antifibrotic effects in the liver and may represent a novel antifibrotic therapy.

Atorvastatin attenuates angiotensin II-induced inflammatory actions in the liver

Statins exert beneficial effects in chronically damaged tissues. Angiotensin II (ANG II) participates in liver fibrogenesis by inducing oxidative stress, inflammation, and transforming growth factor-beta1 (TGF-beta1) expression. We investigate whether atorvastatin modulates ANG II-induced pathogenic effects in the liver. Male Wistar rats were infused with saline or ANG II (100 ng kg(-1) min(-1)) for 4 wk through a subcutaneous osmotic pump. Rats received either vehicle or atorvastatin (5 mg kg(-1) day(-1)) by gavage. ANG II infusion resulted in infiltration of inflammatory cells (CD43 immunostaining), oxidative stress (4-hydroxynonenal), hepatic stellate cells (HSC) activation (smooth muscle alpha-actin), increased intercellular adhesion molecule (ICAM-1), and interleukin-6 hepatic gene expression (quantitative PCR). These effects were markedly blunted in rats receiving atorvastatin. The beneficial effects of atorvastatin were confirmed in an additional model of acute liver injury (carbon tetrachloride administration). We next explored whether the beneficial effects of atorvastatin on ANG II-induced actions are also reproduced at the cellular level. We studied HSC, a cell type with inflammatory and fibrogenic properties. ANG II (10(-8)M) stimulated cell proliferation, proinflammatory actions (NF-kappaB activation, ICAM-1 expression, interleukin-8 secretion) as well as expression of procollagen-alpha(1(I)) and TGF-beta1. All of these effects were reduced in the presence of atorvastatin (10(-7)M). These results indicate that atorvastatin attenuates the pathogenic events induced by ANG II in the liver both in vivo and in vitro. Therefore, statins could have beneficial effects in conditions characterized by hepatic inflammation.

Bradykinin attenuates hepatocellular damage and fibrosis in rats with chronic liver injury

BACKGROUND & AIMS

Recent studies have suggested that the kallikrein-kinin system regulates tissue fibrogenesis. We hypothesize that bradykinin (BK), the main effector peptide of this system, regulates hepatic fibrogenesis.

METHODS

Kallikrein-kinin system components were studied by quantitative reverse-transcription polymerase chain reaction analysis, immunohistochemistry, and Western blotting. The effect of bradykinin on liver injury was studied by infusing saline or bradykinin (1 and 100 ng/kg/min) through a subcutaneous pump into carbon tetrachloride-treated rats and mice treated with Fas-stimulating antibody. Bradykinin effects were studied in cultured hepatic stellate cells (HSCs) and hepatocytes.

RESULTS

Bradykinin receptors and kallikrein-1 were detected in both normal and fibrotic human livers and HSCs. BK receptors were up-regulated in fibrotic livers and activated HSCs. Bradykinin infusion reduced liver damage, as indicated by decreased aminotransferase serum levels and reduced histologic necroinflammatory score without inducing changes in arterial pressure. Moreover, bradykinin attenuated hepatic fibrosis, as indicated by reduced collagen accumulation, smooth muscle alpha-actin content, as well as decreased pro-collagen-alpha1(I) and transforming growth factor-beta1 gene expression. Bradykinin infusion reduced hepatocellular apoptosis induced by anti-Fas-receptor antibody. HSCs responded to bradykinin with intracellular calcium mobilization. Bradykinin reduced procollagen-alpha1(I) and transforming growth factor-beta1 gene expression and induced matrix metalloproteinase-2 activation. Finally, BK induced prosurvival and proliferative intracellular signaling in primary hepatocytes.

CONCLUSIONS

Bradykinin attenuates liver damage and fibrosis development in a rat model of chronic liver injury. Therefore, activation of the kallikrein-kinin system may be a new therapeutic approach to the management of chronic liver disease.

Angiotensin-converting enzyme inhibition by lisinopril enhances liver regeneration in rats

Bradykinin has been reported to act as a growth factor for fibroblasts, mesangial cells and keratinocytes. Recently, we reported that bradykinin augments liver regeneration after partial hepatectomy in rats. Angiotensin-converting enzyme (ACE) is also a powerful bradykinin-degrading enzyme. We have investigated the effect of ACE inhibition by lisinopril on liver regeneration after partial hepatectomy. Adult male Wistar rats underwent 70% partial hepatectomy (PH). The animals received lisinopril at a dose of 1 mg kg body weight(-1) day(-1), or saline solution, intraperitoneally, for 5 days before hepatectomy, and daily after surgery. Four to six animals from the lisinopril and saline groups were sacrificed at 12, 24, 36, 48, 72, and 120 h after PH. Liver regeneration was evaluated by immunohistochemical staining for proliferating cell nuclear antigen using the PC-10 monoclonal antibody. The value for the lisinopril-treated group was three-fold above the corresponding control at 12 h after PH (P<0.001), remaining elevated at approximately two-fold above control values at 24, 36, 48 (P<0.001), and at 72 h (P<0.01) after PH, but values did not reach statistical difference at 120 h after PH. Plasma ACE activity measured by radioenzymatic assay was significantly higher in the saline group than in the lisinopril-treated group (P<0.001), with 81% ACE inhibition. The present study shows that plasma ACE inhibition enhances liver regeneration after PH in rats. Since it was reported that bradykinin also augments liver regeneration after PH, this may explain the liver growth stimulating effect of ACE inhibitors.

Porphyria cutanea tarda in Brazilian patients: association with hemochromatosis C282Y mutation and hepatitis C virus infection

OBJECTIVE

Porphyria cutanea tarda (PCT) is commonly associated with iron overload and hepatitis C virus (HCV) infection. Association between hemochromatosis C282Y or H63D mutations and PCT has been observed, although not uniformly, and iron overload is also commonly found in chronic HCV hepatitis. The aim of the present study was to investigate the frequency of C282Y and H63D mutations and HCV infection in Brazilian patients with PCT and their relationship with iron overload.

METHODS

Twenty-three patients (19 men) aged 39.6 +/- 11.1 yr were studied. All had dermatological lesions of PCT and high levels of urinary uroporphyrin. HCV infection and iron overload were investigated. DNA samples were analyzed for the presence of HFE mutations.

RESULTS

The frequency of C282Y was significantly higher in PCT patients than in 278 healthy individuals (17.4% vs 4%, odds ratio = 5.1, 95% confidence interval 1.5-17.6, p = 0.02), whereas no difference was observed regarding the H63D mutation (30.4% vs 31%, odds ratio = 1, 95% confidence interval 0.4-2.4, p = 1). Biochemical tests in PCT patients showed iron overload with transferrin saturation = 47.3 +/- 20.7% and ferritin = 566.8 +/- 425 ng/ml. Fifteen of 23 (65.2%) patients had HCV infection and alcohol ingestion was observed in 17 of 23 (73.9%).

CONCLUSIONS

PCT patients exhibited evidence of iron overload, a high frequency of HCV, and an association with C282Y mutation. These data further support the notion that both acquired and inherited factors contribute to the occurrence of PCT, and indicate that screening for C282Y may be justified in PCT patients.

Are haemochromatosis mutations related to the severity of liver disease in hepatitis C virus infection?

It has been proposed that iron overload may adversely affect liver disease outcome. The recent identification of 2 mutations in the HFE gene related to hereditary haemochromatosis (Cys282Tyr and His63Asp) provided an opportunity to test whether they are associated with hepatic iron accumulation and the activity and severity of liver disease in hepatitis C virus (HCV) infection. We investigated the prevalence of HFE mutations in 135 male patients with chronic HCV hepatitis, and correlated genotype distribution with different parameters of iron status and the activity and severity of liver disease. Of these 135 patients, 6 (4.4%) carried Cys282Tyr and 32 (23.7%) carried His63Asp, frequencies which were similar to those observed in healthy controls. Serum iron levels and transferrin saturation (but not ferritin levels or liver iron content) were significantly higher in carriers than in non-carriers of HFE mutations. No difference was observed in serum ALT, AST and GGT levels between carriers and non-carriers. Finally, scores for necroinflammatory activity and fibrosis in the liver were significantly higher in HFE carriers than in non-carriers. Patients with chronic HCV infection carrying HFE mutations tend to present more evident body iron accumulation and a higher degree of necroinflammatory activity and fibrosis in the liver. HFE gene mutations might be an additional factor to be considered among those implicated in the determination of a worse prognosis of the liver disease in chronic HCV infection.

[Jejunal myenteric denervation induced by benzalkonium chloride]

The effects of benzalkonium chloride (BAC) on the number of myenteric neurons, muscle thickness and external perimeter after acute (until 10 days after BAC application) and chronic (30 and 60 days after BAC application) denervation of the proximal jejunum were determined in rats. There was a significant reduction in the number of myenteric neurons of all segments treated with BAC. The extent of denervation varied along the time, and it was reduced in the denervated segments of the chronic group in comparison with the acute group. This may be due to the neuroplasticity phenomenon appearing during the chronic phase. Myenteric denervation increased the thickness of the propria muscle layer, especially in the longitudinal muscle layer, suggesting a higher sensitivity of this layer to myenteric denervation.

Myenteric neuron number after acute and chronic denervation of the proximal jejunum induced by benzalkonium chloride

The effects of benzalkonium chloride (BAC) on the number of myenteric neurons after acute (until 10 days after BAC application) and chronic (30 and 60 days after BAC application) denervation of the proximal jejunum were determined in rats. There was a significant reduction in the number of myenteric neurons of all segments treated with BAC. The extent of denervation varied with time, and it was reduced in the denervated segments of the chronic group in comparison with the acute group. This may be due to the neuroplasticity phenomenon appearing during the chronic phase.