Effect of MMP Inhibitors on the Bond Strength of Fibre Posts After Ageing.

AIM: This in vitro study aimed to evaluate the effect of matrix metalloproteinase (MMP) inhibitors on the bond strength of resin-cemented fibre posts to radicular dentin under an aged-loaded condition. MATERIALS AND METHODS: Radicular dentin was prepared and irrigated by MMP inhibitor solution after root canal obturation in 60 extracted single-rooted teeth based on 6 groups: (1) 2% chlorhexidine (CHX) + loaded; (2) CHX + unloaded; (3) 0.5% benzalkonium chloride (BAC) + loaded; (4) BAC + unloaded; (5) 17% ethylenediaminetetraacetic acid (EDTA) + loaded; and (6) EDTA + unloaded. After final rinsing, all specimens were sliced cross-sectionally and kept in a water bath for 12 months of ageing. Groups 1, 3, and 5 were subjected to cyclic loading. Push-out tests were conducted using a universal testing machine, and failure mode was examined. The data were analysed using 3-way analysis of variance and post hoc tests at α = 0.05. RESULTS: BAC + unloaded demonstrated the highest mean bond strength (3.12 ± 0.18 MPa; P < .001), while the BAC + loaded and CHX + loaded groups showed a significantly lower push-out bond strength than their unloaded counterparts. Mixed adhesive-cohesive failure was the most common failure mode observed. CONCLUSIONS: Without cycling loading, BAC was superior to CHX and EDTA in preserving the bond strength of resin-cemented fibre posts after 12 months of ageing. Loading significantly weakened the effectiveness of BAC and CHX in preserving the bond strength.

Fracture Resistance of Endodontically Treated Maxillary Premolars with Non-carious Cervical Lesions Restored with Different Post Systems.

OBJECTIVE: To test the hypothesis that the (i) presence of non-carious cervical lesions (NCCLs) and (ii) type of post system have no effect on the fracture resistance and pattern in endodontically treated maxillary premolars. METHODS: Human maxillary first premolars (n=60) with two root canals were randomly allocated into four groups (n=15). Buccal wedge-shaped NCCLs were prepared in 45 teeth specimens. Following root canal treatment, the specimens were randomly divided into (i) composite resin core (CRC); (ii) NCCLs + composite resin core (NCCL+CRC); (iii) NCCLs+prefabricated fibre-reinforced composite post + composite resin core (NCCL+PFRC+CRC); (iv) NCCLs+custom fibre posts + composite resin core (NCCL+CFP+CRC). All specimens were subjected to thermocycling (5°C to 55°C/5000 cycles). The compressive load was applied non-axially to the palatal cusp with a universal testing machine at a crosshead speed of 0.5 mm/min at a 30° angle until fracture. Fracture patterns were examined using a loupe magnification (2.5×) under transillumination. Statistical analyses were performed using non-parametric tests and pairwise comparisons of the load-to-fracture among the groups. Chi-square test was used to analyse the fracture patterns (P=0.05). RESULTS: Fracture resistance of NCCL+PFRC+CRC was significantly higher than NCCL+CRC (P=0.011), while NCCL+CFP+CRC did not show any significant difference when compared to NCCL+CRC (P=0.089). No statistical difference was found between CRC, NCCL+PFRC+CRC and NCCL+CFP+CRC (P=1.000). The frequencies of favourable fracture patterns in descending orders were as follows: CRC (80%), NCCL+CFP+CRC (73%), NCCL+PFRC+CRC (60%), and NCCL+CRC (40%). Chi-square test did not show significant differences in fracture patterns among all groups (P=0.110). CONCLUSION: Restoration of the endodontically treated maxillary premolars with NCCLs, with or without post, resulted in similar fracture resistance as their counterparts without NCCLs. Placement of a prefabricated fibre-reinforced composite post exhibited greater fracture resistance to the maxillary premolars with restored NCCLs than those without a post. (EEJ-2022-06-077).

Prediction of complications in early-onset pre-eclampsia (PREP): development and external multinational validation of prognostic models.

BACKGROUND: Unexpected clinical deterioration before 34 weeks gestation is an undesired course in early-onset pre-eclampsia. To safely prolong preterm gestation, accurate and timely prediction of complications is required. METHOD: Women with confirmed early onset pre-eclampsia were recruited from 53 maternity units in the UK to a large prospective cohort study (PREP-946) for development of prognostic models for the overall risk of experiencing a complication using logistic regression (PREP-L), and for predicting the time to adverse maternal outcome using a survival model (PREP-S). External validation of the models were carried out in a multinational cohort (PIERS-634) and another cohort from the Netherlands (PETRA-216). Main outcome measures were C-statistics to summarise discrimination of the models and calibration plots and calibration slopes. RESULTS: A total of 169 mothers (18%) in the PREP dataset had adverse outcomes by 48 hours, and 633 (67%) by discharge. The C-statistics of the models for predicting complications by 48 hours and by discharge were 0.84 (95% CI, 0.81-0.87; PREP-S) and 0.82 (0.80-0.84; PREP-L), respectively. The PREP-S model included maternal age, gestation, medical history, systolic blood pressure, deep tendon reflexes, urine protein creatinine ratio, platelets, serum alanine amino transaminase, urea, creatinine, oxygen saturation and treatment with antihypertensives or magnesium sulfate. The PREP-L model included the above except deep tendon reflexes, serum alanine amino transaminase and creatinine. On validation in the external PIERS dataset, the reduced PREP-S model showed reasonable calibration (slope 0.80) and discrimination (C-statistic 0.75) for predicting adverse outcome by 48 hours. Reduced PREP-L model showed excellent calibration (slope: 0.93 PIERS, 0.90 PETRA) and discrimination (0.81 PIERS, 0.75 PETRA) for predicting risk by discharge in the two external datasets. CONCLUSIONS: PREP models can be used to obtain predictions of adverse maternal outcome risk, including early preterm delivery, by 48 hours (PREP-S) and by discharge (PREP-L), in women with early onset pre-eclampsia in the context of current care. They have a potential role in triaging high-risk mothers who may need transfer to tertiary units for intensive maternal and neonatal care. TRIAL REGISTRATION: ISRCTN40384046 , retrospectively registered.

Prospective risk of stillbirth and neonatal complications in twin pregnancies: systematic review and meta-analysis.

OBJECTIVE: To determine the risks of stillbirth and neonatal complications by gestational age in uncomplicated monochorionic and dichorionic twin pregnancies. DESIGN: Systematic review and meta-analysis. DATA SOURCES: Medline, Embase, and Cochrane databases (until December 2015). REVIEW METHODS: Databases were searched without language restrictions for studies of women with uncomplicated twin pregnancies that reported rates of stillbirth and neonatal outcomes at various gestational ages. Pregnancies with unclear chorionicity, monoamnionicity, and twin to twin transfusion syndrome were excluded. Meta-analyses of observational studies and cohorts nested within randomised studies were undertaken. Prospective risk of stillbirth was computed for each study at a given week of gestation and compared with the risk of neonatal death among deliveries in the same week. Gestational age specific differences in risk were estimated for stillbirths and neonatal deaths in monochorionic and dichorionic twin pregnancies after 34 weeks' gestation. RESULTS: 32 studies (29 685 dichorionic, 5486 monochorionic pregnancies) were included. In dichorionic twin pregnancies beyond 34 weeks (15 studies, 17 830 pregnancies), the prospective weekly risk of stillbirths from expectant management and the risk of neonatal death from delivery were balanced at 37 weeks' gestation (risk difference 1.2/1000, 95% confidence interval -1.3 to 3.6; I(2)=0%). Delay in delivery by a week (to 38 weeks) led to an additional 8.8 perinatal deaths per 1000 pregnancies (95% confidence interval 3.6 to 14.0/1000; I(2)=0%) compared with the previous week. In monochorionic pregnancies beyond 34 weeks (13 studies, 2149 pregnancies), there was a trend towards an increase in stillbirths compared with neonatal deaths after 36 weeks, with an additional 2.5 per 1000 perinatal deaths, which was not significant (-12.4 to 17.4/1000; I(2)=0%). The rates of neonatal morbidity showed a consistent reduction with increasing gestational age in monochorionic and dichorionic pregnancies, and admission to the neonatal intensive care unit was the commonest neonatal complication. The actual risk of stillbirth near term might be higher than reported estimates because of the policy of planned delivery in twin pregnancies. CONCLUSIONS: To minimise perinatal deaths, in uncomplicated dichorionic twin pregnancies delivery should be considered at 37 weeks' gestation; in monochorionic pregnancies delivery should be considered at 36 weeks. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42014007538.

Prognostic models in obstetrics: available, but far from applicable.

Health care provision is increasingly focused on the prediction of patients' individual risk for developing a particular health outcome in planning further tests and treatments. There has been a steady increase in the development and publication of prognostic models for various maternal and fetal outcomes in obstetrics. We undertook a systematic review to give an overview of the current status of available prognostic models in obstetrics in the context of their potential advantages and the process of developing and validating models. Important aspects to consider when assessing a prognostic model are discussed and recommendations on how to proceed on this within the obstetric domain are given. We searched MEDLINE (up to July 2012) for articles developing prognostic models in obstetrics. We identified 177 papers that reported the development of 263 prognostic models for 40 different outcomes. The most frequently predicted outcomes were preeclampsia (n = 69), preterm delivery (n = 63), mode of delivery (n = 22), gestational hypertension (n = 11), and small-for-gestational-age infants (n = 10). The performance of newer models was generally not better than that of older models predicting the same outcome. The most important measures of predictive accuracy (ie, a model's discrimination and calibration) were often (82.9%, 218/263) not both assessed. Very few developed models were validated in data other than the development data (8.7%, 23/263). Only two-thirds of the papers (62.4%, 164/263) presented the model such that validation in other populations was possible, and the clinical applicability was discussed in only 11.0% (29/263). The impact of developed models on clinical practice was unknown. We identified a large number of prognostic models in obstetrics, but there is relatively little evidence about their performance, impact, and usefulness in clinical practice so that at this point, clinical implementation cannot be recommended. New efforts should be directed toward evaluating the performance and impact of the existing models.

Epilepsy in pregnancy and reproductive outcomes: a systematic review and meta-analysis.

BACKGROUND: Antenatal care of women with epilepsy is varied. The association of epilepsy and antiepileptic drug exposure with pregnancy outcomes needs to be quantified to guide management. We did a systematic review and meta-analysis to investigate the association between epilepsy and reproductive outcomes, with or without exposure to antiepileptic drugs. METHODS: We searched MEDLINE, Embase, Cochrane, AMED, and CINAHL between Jan 1, 1990, and Jan 21, 2015, with no language or regional restrictions, for observational studies of pregnant women with epilepsy, which assessed the risk of obstetric complications in the antenatal, intrapartum, or postnatal period, and any neonatal complications. We used the Newcastle-Ottawa Scale to assess the methodological quality of the included studies, risk of bias in the selection and comparability of cohorts, and outcome. We assessed the odds of maternal and fetal complications (excluding congenital malformations) by comparing pregnant women with and without epilepsy and undertook subgroup analysis based on antiepileptic drug exposure in women with epilepsy. We summarised the association as odds ratio (OR; 95% CI) using random effects meta-analysis. The PROSPERO ID of this Systematic Review's protocol is CRD42014007547. FINDINGS: Of 7050 citations identified, 38 studies from low-income and high-income countries met our inclusion criteria (39 articles including 2,837,325 pregnancies). Women with epilepsy versus those without (2,809,984 pregnancies) had increased odds of spontaneous miscarriage (OR 1·54, 95% CI 1·02-2·32; I(2)=67%), antepartum haemorrhage (1·49, 1·01-2·20; I(2)=37%), post-partum haemorrhage (1·29, 1·13-1·49; I(2)=41%), hypertensive disorders (1·37, 1·21-1·55; I(2)=23%), induction of labour (1·67, 1·31-2·11; I(2)=64%), caesarean section (1·40, 1·23-1·58; I(2)=66%), any preterm birth (<37 weeks of gestation; 1·16, 1·01-1·34; I(2)=64%), and fetal growth restriction (1·26, 1·20-1·33; I(2)=1%). The odds of early preterm birth, gestational diabetes, fetal death or stillbirth, perinatal death, or admission to neonatal intensive care unit did not differ between women with epilepsy and those without the disorder. INTERPRETATION: A small but significant association of epilepsy, exposure to antiepileptic drugs, and adverse outcomes exists in pregnancy. This increased risk should be taken into account when counselling women with epilepsy. FUNDING: EBM CONNECT Collaboration.

Isolation and characterization of embryonic stem cell-derived cardiac Purkinje cells.

The cardiac Purkinje fiber network is composed of highly specialized cardiomyocytes responsible for the synchronous excitation and contraction of the ventricles. Computational modeling, experimental animal studies, and intracardiac electrical recordings from patients with heritable and acquired forms of heart disease suggest that Purkinje cells (PCs) may also serve as critical triggers of life-threatening arrhythmias. Nonetheless, owing to the difficulty in isolating and studying this rare population of cells, the precise role of PC in arrhythmogenesis and the underlying molecular mechanisms responsible for their proarrhythmic behavior are not fully characterized. Conceptually, a stem cell-based model system might facilitate studies of PC-dependent arrhythmia mechanisms and serve as a platform to test novel therapeutics. Here, we describe the generation of murine embryonic stem cells (ESC) harboring pan-cardiomyocyte and PC-specific reporter genes. We demonstrate that the dual reporter gene strategy may be used to identify and isolate the rare ESC-derived PC (ESC-PC) from a mixed population of cardiogenic cells. ESC-PC display transcriptional signatures and functional properties, including action potentials, intracellular calcium cycling, and chronotropic behavior comparable to endogenous PC. Our results suggest that stem-cell derived PC are a feasible new platform for studies of developmental biology, disease pathogenesis, and screening for novel antiarrhythmic therapies.

Early and delayed tranilast treatment reduces pathological fibrosis following myocardial infarction.

BACKGROUND: Tranilast has been shown to inhibit TGFß1-related fibrosis and organ failure in various disease models. We sought to examine the effects of tranilast on left ventricular (LV) remodelling post-MI. METHODS: Following coronary artery ligation, Sprague Dawley rats were randomised to receive tranilast (300mg/kg/d, p.o.) or vehicle control over one of two treatment periods: (1) from 24h until seven days post-MI, (2) from seven days to 28 days post-MI. Cardiac tissue was harvested for molecular, immunohistochemical and cell culture analyses. RESULTS: Tranilast treatment of MI rats from 24h until seven days post-MI reduced myocardial collagen content, α1 (I) procollagen, TGFß1 and CTGF mRNA transcripts, monocyte/macrophage infiltration and exacerbated infarct expansion compared with vehicle-treatment. Delaying the commencement of tranilast treatment to seven days post-MI attenuated myocardial fibrosis, gene expression of α1(I) procollagen, α1(III) procollagen, fibronectin, TGFß1 and CTGF mRNA transcripts, and monocyte/macrophage infiltration at 28d compared to vehicle-treatment, without detriment to infarct healing. Extended post-MI also preserved LV infarct size. In cultures of rat cardiac fibroblasts, tranilast attenuated TGFß1-stimulated fibrogenesis. CONCLUSION: Tranilast inhibits myocardial TGFß1 expression, fibrosis in rat post-MI and collagen production in cardiac fibroblasts. While tranilast intervention from 24h post-MI exacerbated infarct expansion, delaying the commencement of treatment to seven days post-MI impeded LV remodelling.

Therapeutic effects of human STRO-3-selected mesenchymal precursor cells and their soluble factors in experimental myocardial ischemia.

Stromal precursor antigen (STRO)-3 has previously been shown to identify a subset of adult human bone marrow (BM)-derived mesenchymal lineage precursors, which may have cardioprotective potential. We sought to characterize STRO-3-immunoselected and culture-expanded mesenchymal precursor cells (MPCs) with respect to their biology and therapeutic potential in myocardial ischemia. Immunoselection of STRO-3(+) MPCs enriched for fibroblastic colony forming units from unfractionated BM mononuclear cells (MNCs). Compared to mesenchymal stem cells conventionally isolated by plastic adherence, MPCs demonstrated increased proliferative capacity during culture expansion, expressed higher levels of early 'stem cell' markers and various pro-angiogenic and cardioprotective cytokines, and exhibited greater trilineage developmental efficiency. Intramyocardial injection of MPCs into a rat model of myocardial infarction (MI) promoted left ventricular recovery and inhibited left ventricular dilatation. These beneficial effects were associated with cardioprotective and pro-angiogenic effects at the tissue level, despite poor engraftment of cells. Treatment of MI rats with MPC-conditioned medium (CM) preserved left ventricular function and dimensions, reduced myocyte apoptosis and fibrosis, and augmented neovascularization, involving both resident vascular cells and circulating endothelial progenitor cells (EPCs). Profiling of CM revealed various cardioprotective and pro-angiogenic factors, which had biological activity in cultures of myocytes, tissue-resident vascular cells and EPCs. Prospective immunoselection of STRO-3(+) MPCs from BM MNCs conferred advantage in maintaining a population of immature MPCs during ex vivo expansion. Transplantation of culture-expanded MPCs into the post-MI heart resulted in therapeutic benefit, attributable at least in part to paracrine mechanisms of action. Thus, MPCs represent a promising therapy for myocardial ischemia.

Alternatively spliced RAGEv1 inhibits tumorigenesis through suppression of JNK signaling.

Receptor for advanced glycation end products (RAGE) and its ligands are overexpressed in multiple cancers. RAGE has been implicated in tumorigenesis and metastasis, but little is known of the mechanisms involved. In this study, we define a specific functional role for an alternate splice variant termed RAGE splice variant 1 (RAGEv1), which encodes a soluble endogenous form of the receptor that inhibits tumorigenesis. RAGEv1 was downregulated in lung, prostate, and brain tumors relative to control matched tissues. Overexpressing RAGEv1 in tumor cells altered RAGE ligand stimulation of several novel classes of genes that are critical in tumorigenesis and metastasis. Additionally, RAGEv1 inhibited tumor formation, cell invasion, and angiogenesis induced by RAGE ligand signaling. Analysis of signal transduction pathways underlying these effects revealed marked suppression of c-jun-NH(2)-kinase (JNK) pathway signaling, and JNK inhibition suppressed signaling through the RAGE pathway. Tumors expressing RAGEv1 were significantly smaller than wild-type tumors and displayed prominently reduced activation of JNK. Our results identify RAGEv1 as a novel suppressor, the study of which may offer new cancer therapeutic directions.

Islet grafting and imaging in a bioengineered intramuscular space.

BACKGROUND: Because the hepatic portal system may not be the optimal site for islet transplantation, several extrahepatic sites have been studied. Here, we examine an intramuscular transplantation site, bioengineered to better support islet neovascularization, engraftment, and survival, and we demonstrate that at this novel site, grafted beta cell mass may be quantitated in a real-time noninvasive manner by positron emission tomography (PET) imaging. METHODS: Streptozotocin-induced rats were pretreated intramuscularly with a biocompatible angiogenic scaffold received syngeneic islet transplants 2 weeks later. The recipients were monitored serially by blood glucose and glucose tolerance measurements and by PET imaging of the transplant site with [11C] dihydrotetrabenazine. Parallel histopathologic evaluation of the grafts was performed using insulin staining and evaluation of microvasularity. RESULTS: Reversal of hyperglycemia by islet transplantation was most successful in recipients pretreated with bioscaffolds containing angiogenic factors when compared with those who received no bioscaffolds or bioscaffolds not treated with angiogenic factors. PET imaging with [11C] dihydrotetrabenazine, insulin staining, and microvascular density patterns were consistent with islet survival, increased levels of angiogenesis, and with reversal of hyperglycemia. CONCLUSIONS: Induction of increased neovascularization at an intramuscular site significantly improves islet transplant engraftment and survival compared with controls. The use of a nonhepatic transplant site may avoid intrahepatic complications and permit the use of PET imaging to measure and follow transplanted beta cell mass in real time. These findings have important implications for effective islet implantation outside of the liver and offer promising possibilities for improving islet survival, monitoring, and even prevention of islet loss.

A DNA enzyme against plasminogen activator inhibitor- type 1 (PAI-1) limits neointima formation after angioplasty in an obese diabetic rodent model.

We investigated whether targeted cleavage of PAI-1 mRNA might prevent post-angioplasty neointima formation in diabetic JCR:LA-cp/cp rats with naturally elevated PAI-1 levels. Catalytic DNA enzymes targeting rat PAI-1 mRNA (PAI-1 DNA enzyme, n = 12) or a random sequence as control (scrambled DNA enzyme, n = 12) were infused at the site of arterial damage. Control animals demonstrated prominent PAI-1 protein expression in the arterial endothelium at 48 hours, and robust neointimal proliferation by two weeks, with 60 +/- 10% mean occlusion of the artery lumen. The neointimal lesion consisted of dense fibrin deposition and numerous proliferating smooth muscle cells, as determined by dual alpha-smooth muscle actin/Ki67 expression. Treatment with PAI-1 DNA enzyme resulted in marked early (48 hour) reduction of endothelial PAI-1 protein expression, which persisted for the next two weeks as well as a two fold reduction of expression of PAI-1 mRNA by RT-PCR at the same time point, (P < 0.05). By two weeks, PAI-1 DNA enzyme treated animals demonstrated significantly reduced levels of fibrin deposition and 5-fold lower levels of proliferating smooth muscle cells at the site of arterial injury compared to controls (P < 0.01), and a 2-fold lower neointima/media ratio (0.67 +/- 0.11 vs 1.39 +/- 0.12) (P < 0.05). Treatment with a catalytic PAI-1 DNA enzyme successfully prevents neointimal proliferation after balloon injury in diabetic animals.

Mesenchymal lineage precursor cells induce vascular network formation in ischemic myocardium.

Mesenchymal lineage precursors can be reproducibly isolated from adult mammalian bone marrow and grown in culture. Immunoselection with monoclonal antibodies against STRO-1 and vascular-cell-adhesion molecule 1 (VCAM1/CD106) prior to expansion results in a 1,000-fold enrichment of mesenchymal precursors compared to standard isolation techniques. Intramyocardial injection of human STRO-1-selected precursors in an athymic rat model of acute myocardial infarction results in induction of vascular network formation and arteriogenesis coupled with global functional cardiac recovery.

Catalytic degradation of vitamin D up-regulated protein 1 mRNA enhances cardiomyocyte survival and prevents left ventricular remodeling after myocardial ischemia.

Vitamin D3 up-regulated protein 1 (VDUP1) is a key mediator of oxidative stress on various cellular processes via downstream effects on apoptosis signaling kinase 1 (ASK1) and p38 mitogen-activated protein kinase (MAPK). Here, we report that VDUP1 expression is significantly increased in rat hearts following acute myocardial ischemia, suggesting it may have important regulatory effects on cardiac physiological processes during periods of oxidative stress. Transfection of H9C2 cardiomyoblasts with a sequence-specific VDUP1 DNA enzyme to down-regulate VDUP1 mRNA expression significantly reduced apoptosis and enhanced cell survival under conditions of H(2)O(2) stress, and these effects involved inhibition of ASK1 activity. Direct intracardiac injection of the DNA enzyme at the time of acute myocardial infarction reduced myocardial VDUP1 mRNA expression and resulted in prolonged reduction in cardiomyocyte apoptosis and ASK1 activity. Moreover, down-regulation of VDUP1 was accompanied by significant reduction in cardiac expression of pro-collagen type I alpha2 mRNA level, as well as marked reduction in myocardial scar formation. These features were accompanied by significant improvement in cardiac function. Together, these results suggest a direct role for VDUP1 in the adverse effects of ischemia and oxidative stress on cardiomyocyte survival, left ventricular collagen deposition, and cardiac function. Strategies to inhibit VDUP1 expression and/or function during acute ischemic events may be beneficial to cardiac functional recovery and prevention of left ventricular remodeling.

Fibrosis as a therapeutic target post-myocardial infarction.

The extracellular matrix (ECM) is a dynamic microenvironment and a major contributor to the adverse ventricular remodelling that follows myocardial infarction (MI), via activation of both direct pro-fibrotic pathways and matrix metalloproteinases (MMPs) that enhance collagenase activity. Reactive fibrosis, i.e. deposition of ECM materials remote from the region of the MI is clearly detrimental to ventricular function and contributory to adverse outcomes post-MI. Therefore, reversal of this process represents an important therapeutic target in post-MI management and treatment of established heart failure. A number of existing agents exert their beneficial effects in part via reductions in ECM deposition. Furthermore, specific anti-fibrotic drugs have been developed and are currently being explored for these and other cardiac conditions where pathological ECM deposition is felt to be contributory to disease progression.

Tranilast attenuates cardiac matrix deposition in experimental diabetes: role of transforming growth factor-beta.

OBJECTIVE: The pathological accumulation of extracellular matrix is a characteristic feature of diabetic cardiomyopathy that is directly related to a loss of function. Tranilast (n-[3,4-anthranilic acid), used for the treatment of fibrotic skin diseases, has also been shown to inhibit transforming growth factor-beta (TGF-beta)-induced matrix production in kidney epithelial cells. METHODS: To investigate the effects of tranilast in the diabetic heart, we examined its effects in cultured cardiac fibroblasts and then assessed its effects in (mRen-2)27 diabetic rats with established disease (8 weeks after streptozotocin). RESULTS: In vitro studies demonstrated a 58% reduction in TGF-beta1-induced 3[H]-hydroxyproline incorporation with tranilast 30 microM (p<0.01). At 16 weeks, diabetes in the Ren-2 rat was associated with increased cardiac fibrosis and evidence of TGF-beta1 activation, as measured by the abundance of phosphorylated Smad2. Despite persistent hyperglycaemia and hypertension, tranilast attenuated cardiac fibrosis by 37% (p<0.05) in association with reduction in phospho-Smad2 (p<0.01). CONCLUSION: These findings indicate that tranilast has antifibrotic actions in the Ren-2 model of experimental diabetic cardiac disease by mechanisms that might attributable to reduced TGF-beta activity.

Cardiovascular role of urotensin II: effect of chronic infusion in the rat.

Urotensin II (UII) is a potent vaso-active peptide thought to have multiple roles in the regulation of cardiovascular physiology and pathophysiology. The actions of UII are complex and difficult to interpret given its systemic hemodynamic effects and variable action on different vascular beds and isolated vessels. Direct effects of UII on the myocardium, include myocyte hypertrophy, extracellular matrix deposition and contractility. These observations, together with elevated plasma levels found in disease, are common traits reported in other pathophysiologically implicated neurohormonal systems. In this review, we include original data obtained from chronic infusion of UII in rats. We report a reduction in first derivative of left ventricular pressure (+dP/dt), as well as an increase in the ratio of left ventricular collagen I:III, that may contribute to the reduced myocardial contractility observed in these animals.

p38 mitogen-activated protein kinase inhibition improves cardiac function and attenuates left ventricular remodeling following myocardial infarction in the rat.

OBJECTIVES: The aim of this study was to examine the effect of the p38 mitogen-activated protein kinase (MAPK) inhibitor, RWJ-67657 (RWJ), on left ventricular (LV) dysfunction and remodeling post-myocardial infarction (MI) in rats. BACKGROUND: p38 MAPK signaling has been implicated in the progression of chronic heart failure. METHODS: From day 7 post-MI (coronary artery ligation), rats received either RWJ (50 mg/day, by gavage, n = 8, MI+RWJ) or vehicle (by gavage, n = 8, MI+V) for 21 days. Echocardiography was performed on day 6, before the commencement of treatment, and on day 27. In vivo hemodynamic measurements were made on day 28. Sham-operated rats served as controls. RESULTS: The LV end-diastolic pressure and lung/body weight ratio were reduced, whereas the maximum rate of rise of LV pressure was increased towards sham levels in MI+RWJ compared with MI+V. Baseline echocardiographic studies demonstrated uniform LV remodeling and dysfunction in MI rats. Fractional shortening (FS) further deteriorated in MI+V, whereas FS was preserved in MI+RWJ. Progressive LV dilation and infarct expansion observed in MI+V were inhibited in MI+RWJ. MI+RWJ also demonstrated increased myocyte hypertrophy in the peri-infarct and non-infarct zones, and reduced myocardial collagen and alpha-smooth muscle actin (SMA) immunoreactivity compared with MI+V. The antifibrotic effects of RWJ in vivo may reflect direct effects on cardiac fibroblasts, because RWJ attenuated transforming growth factor beta-1-stimulated collagen synthesis and alpha-SMA expression in isolated cardiac fibroblasts. RWJ also protected cultured myocytes from hydrogen peroxide-induced apoptosis. CONCLUSIONS: RWJ-67657 treatment post-MI had beneficial effects on LV remodeling and dysfunction, supporting a key role for p38 MAPK in pathologic cell signaling in these processes and its inhibition as a novel therapy.

Direct actions of urotensin II on the heart: implications for cardiac fibrosis and hypertrophy.

Urotensin II (UII) is a somatostatin-like peptide recently identified as a potent vasoconstrictor. In this study, we examined whether UII promotes cardiac remodeling through nonhemodynamic effects on the myocardium. In a rat model of heart failure after myocardial infarction (MI), increased UII peptide and UII receptor protein expression was observed in both infarct and noninfarct regions of the left ventricle compared with sham. Moreover, post-MI remodeling was associated with a significant 75% increase in UII receptor gene expression in the heart (P<0.05 versus sham controls), with this increase noted in both regions of the left ventricle. In vitro, UII (10-7 mol/L) stimulation of neonatal cardiac fibroblasts increased the level of mRNA transcripts for procollagens alpha1(I), alpha1(III), and fibronectin by 139+/-15% (P<0.01), 59+/-5% (P<0.05), and 141+/-14% (P<0.01), respectively, with a concomitant 23+/-2% increase in collagen peptide synthesis as determined by 3H-proline incorporation (P<0.01). UII had no effect on cellular hypertrophy, as determined by changes in total protein content in isolated neonatal cardiomyocytes. However, expression of recombinant rat UII receptor in neonatal cardiomyocytes resulted in significant UII-dependent activation of hypertrophic signaling as demonstrated by increased total protein content (unstimulated, 122.4+/-4.0 microg/well; rat UII, 147.6+/-7.0 microg/well; P<0.01) and activation of the hypertrophic phenotype through Galpha(q)- and Ras-dependent pathways. These results indicate that, in addition to potent hemodynamic effects, UII may be implicated in myocardial fibrogenesis through increased collagen synthesis by cardiac fibroblasts and may also be an important determinant of pathological cardiac hypertrophy in conditions characterized by UII receptor upregulation.