Intervenções cirúrgicas para o tratamento do pectus excavatum: revisão sistemática

Pós-graduação em Bases Gerais da Cirurgia - FMB

Exercise training prevents oxidative stress and ubiquitin-proteasome system overactivity and reverse skeletal muscle atrophy in heart failure

Background: Heart failure (HF) is known to lead to skeletal muscle atrophy and dysfunction. However, intracellular mechanisms underlying HF-induced myopathy are not fully understood. We hypothesized that HF would increase oxidative stress and ubiquitin-proteasome system (UPS) activation in skeletal muscle of sympathetic hyperactivity mouse model. We also tested the hypothesis that aerobic exercise training (AET) would reestablish UPS activation in mice and human HF. Methods/Principal Findings: Time-course evaluation of plantaris muscle cross-sectional area, lipid hydroperoxidation, protein carbonylation and chymotrypsin-like proteasome activity was performed in a mouse model of sympathetic hyperactivity-induced HF. At the 7th month of age, HF mice displayed skeletal muscle atrophy, increased oxidative stress and UPS overactivation. Moderate-intensity AET restored lipid hydroperoxides and carbonylated protein levels paralleled by reduced E3 ligases mRNA levels, and reestablished chymotrypsin-like proteasome activity and plantaris trophicity. In human HF (patients randomized to sedentary or moderate-intensity AET protocol), skeletal muscle chymotrypsin-like proteasome activity was also increased and AET restored it to healthy control subjects' levels. Conclusions: Collectively, our data provide evidence that AET effectively counteracts redox imbalance and UPS overactivation, preventing skeletal myopathy and exercise intolerance in sympathetic hyperactivity-induced HF in mice. Of particular interest, AET attenuates skeletal muscle proteasome activity paralleled by improved aerobic capacity in HF patients, which is not achieved by drug treatment itself. Altogether these findings strengthen the clinical relevance of AET in the treatment of HF.

Local Injections of Adipose-Derived Mesenchymal Stem Cells Modulate Inflammation and Increase Angiogenesis Ameliorating the Dystrophic Phenotype in Dystrophin-Deficient Skeletal Muscle

The effects of adipose-derived mesenchymal stem cells (ADMSC) transplantation on degeneration, regeneration and skeletal muscle function were investigated in dystrophin-deficient mice (24-week-old). ADMSC transplantation improved muscle strength and, resistance to fatigue. An increase in fiber cross-sectional area and in the number of fibers with centralized nuclei and augment of myogenin content were observed. In ADMSC-treated muscles a decrease in muscle content of TNF-alpha, IL-6 and oxidative stress measured by Amplex(A (R)) reagent were observed. The level of TGF-beta 1 was lowered whereas that of VEGF, IL-10 and IL-4 were increased by ADMSC treatment. An increase in markers of macrophage M1 (CD11 and F4-80) and a decrease in T lymphocyte marker (CD3) and arginase-1 were also observed in ADMSCs-treated dystrophic muscle. No change was observed in iNOS expression. Increased phosphorylation of Akt, p70S6k and 4E-BP1 was found in dystrophic muscles treated with ADMSC. These results suggest that ADMSC transplantation modulates inflammation and improves muscle tissue regeneration, ameliorating the dystrophic phenotype in dystrophin-deficient mice.

Transient Lymphadenopathy Secondary to Nephrotic Syndrome

Mediastinal lymphadenomegaly secondary to hypervolemia is an underdiagnosed tomographic finding. Herein we describe, in a patient with normal cardiac function, findings of pulmonary congestion associated to lymph node enlargement. The nephrotic syndrome causing hypoalbuminemia, low plasma colloid osmotic pressure and augmented transcapillary fluid leakage was the probable cause of the radiological findings.

Experimental gestational hypothyroidism evokes hypertension in adult offspring rats

Gestational hypothyroidism is a prevalent disorder in pregnant women. We aimed to investigate the impact of experimental gestational hypothyroidism (EGH) on cardiovascular and autonomic nervous systems (ANS) in the offspring of rats. EGH was induced with methimazole (MMI) 0.02% in drinking water from day 9 of gestation until birth. Sixty day old offspring from MMI-treated dams (OMTD, n = 13) or water-treated dams (OWTD, n = 13) had femoral arteries surgically assessed for the measurements of heart rate (HR), mean (MAP), systolic (SAP) and diastolic arterial pressure (DAP), and spontaneous baroreflex sensitivity (BRS). To investigate the balance of ANS, we established the high (HF) and low frequency (LF) bands of pulse interval (PI) and LF band of SAP spectrum. OMTD had increased MAP (130.2 +/- 2.0 vs 108.8 +/- 3.0 mm Hg, p<0.001), SAP (157.3 +/- 2.9 vs 135.7 +/- 4.5 mm Hg, p<0.001) and DAP (109.7 +/- 1.9 vs 88.4 +/- 2.6 mm Hg, p<0.001) when compared to OWED, and had lower HR (355.1 +/- 8.9 vs 386.8 +/- 9.2 bpm, p<0.05). After spectral analysis of PI and SAP, only LF band of SAP spectrum was higher (7.2 +/- 0.8 vs 4.0 +/- 0.6 mm Hg-2, p<0.01) in OMTD under spontaneous condition. Despite bradycardia, EGH promotes spontaneous hypertension in 60 day old offspring, probably due to increased sympathetic modulation of vessels, which is suggested by the higher LF of SAP. These findings suggest a critical role of maternal THs in the development of fetal cardiovascular and autonomic nervous systems. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.

Insulin alone or with captopril: effects on signaling pathways (AKT and AMPK) and oxidative balance after ischemia-reperfusion in isolated hearts

Insulin and the inhibition of the reninangiotensin system have independent benefits for ischemiareperfusion injury, but their combination has not been tested. Our aim was to evaluate the effects of insulin+captopril on insulin/angiotensin signaling pathways and cardiac function in the isolated heart subjected to ischemiareperfusion. Isolated hearts were perfused (Langendorff technique) with KrebsHenseleit (KH) buffer for 25 min. Global ischemia was induced (20 min), followed by reperfusion (30 min) with KH (group KH), KH+angiotensin-I (group A), KH+angiotensin-I+captopril (group AC), KH+insulin (group I), KH+insulin+angiotensin-I (group IA), or KH+insulin+angiotensin-I+captopril (group IAC). Group A had a 24% reduction in developed pressure and an increase in end-diastolic pressure vs. baseline, effects that were reverted in groups AC, IA, and IAC. The phosphorylation of protein kinase B (AKT) was higher in groups I and IA vs. groups KH and A. The phosphorylation of AMP-activated protein kinase (AMPK) was similar to 31% higher in groups I, IA, and IAC vs. groups KH, A, and AC. The tert-butyl hydroperoxide (tBOOH)-induced chemiluminescence was lower (similar to 2.2 times) in all groups vs. group KH and was similar to 35% lower in group IA vs. group A. Superoxide dismutase content was lower in groups A, AC, and IAC vs. group KH. Catalase activity was similar to 28% lower in all groups (except group IA) vs. group KH. During reperfusion of the ischemic heart, insulin activates the AKT and AMPK pathways and inhibits the deleterious effects of angiotensin-I perfusion on SOD expression and cardiac function. The addition of captopril does not potentiate these effects.

Time course of hydrogen peroxide-thioredoxin balance and its influence on the intracellular signalling in myocardial infarction

We investigated the myocardial thioredoxin-1 and hydrogen peroxide concentrations and their association with some prosurvival and pro-apoptotic proteins, during the transition from myocardial infarction (MI) to heart failure in rats. Male Wistar rats were divided into the following six groups: three sham-operated groups and three MI groups, each at at 2, 7 and 28 days postsurgery. Cardiac function was analysed by echocardiography; the concentration of H2O2 and the ratio of reduced to oxidized glutathione were measured spectrophotometrically, while the myocardial immunocontent of thioredoxin-1, angiotensin II, angiotensin II type 1 and type 2 receptors, p-JNK/JNK, p-ERK/ERK, p-Akt/Akt, p-mTOR/mTOR and p-GSK3 beta/GSK3 beta was evaluated by Western blot. Our results show that thioredoxin-1 appears to make an important contribution to the reduced H2O2 concentration. It was associated with lower JNK expression in the early period post-MI (2 days). However, thioredoxin-1 decreased, while reninangiotensin system markers and levels of H2O2 increased, over 28 days post-MI, in parallel with some signalling proteins involved in maladaptative cardiac remodelling and ventricular dysfunction. These findings provide insight into the time course profile of endogenous antioxidant adaptation to ischaemic injury, which may be useful for the design of therapeutical strategies targeting oxidative stress post-MI.

Theophylline is able to partially revert cachexia in tumour-bearing rats

Abstract Background and aims The aim of the present investigation was to examine the anti-wasting effects of theophylline (a methylxantine present in tea leaves) on a rat model of cancer cachexia. Methods The in vitro effects of the nutraceuticals on proteolysis were examined on muscle cell cultures submitted to hyperthermia. Individual muscle weights, muscle gene expression, body composition and cardiac function were measured in rats bearing the Yoshida AH-130 ascites hepatoma, following theophylline treatment. Results Theophylline treatment inhibited proteolysis in C2C12 cell line and resulted in an anti-proteolytic effect on muscle tissue (soleus and heart), which was associated with a decrease in circulating TNF-alpha levels and with a decreased proteolytic systems gene expression. Treatment with the nutraceutical also resulted in an improvement in body composition and cardiac function. Conclusion Theophylline - alone or in combination with drugs - may be a candidate molecule for the treatment of cancer cachexia.

Angiotensin II type 2 receptor (AT2R) is associated with increased tolerance of the hyperthyroid heart to ischemia-reperfusion

Background Thyroid hormone induces cardiac hypertrophy and preconditions the myocardium against Ischemia/Reperfusion (I/R) injury. Type 2 Angiotensin II receptors (AT2R) are shown to be upregulated in cardiac hypertrophy observed in hyperthyroidism and this receptor has been reported to mediate cardioprotection against ischemic injury. Methods The aim of the present study was to evaluate the role of AT2R in the recovery of myocardium after I/R in isolated hearts from T3 treated rats. MaleWistar rats were treated with triiodothyronine (T3; 7 μg/100 gBW/day, i.p.) in the presence or not of a specific AT2R blocker (PD123,319; 10 mg/Kg) for 14 days, while normal rats served as control. After treatment, isolated hearts were perfused in Langendorff mode; after 30 min of stabilization, hearts were subjected to 20 min of zero-flow global ischemia followed by 25 min, 35 min and 45 min of reperfusion. Results T3 treatment induced cardiac hypertrophy, which was not changed by PD treatment. Post-ischemic recovery of cardiac function was increased in T3-treated hearts after 35 min and 45 min of reperfusion as compared to control and the ischemic contracture was accelerated and intensified. AT2R blockade was able to return the evaluated functional parameters of cardiac performance (LVDP, +dP/dtmáx and −dP/dtmin) to the control condition. Furthermore, AT2R blockade prevented the increase in AMPK expression levels induced by T3, suggesting its possible involvement in this process. Conclusion AT2R plays a significant role in T3-induced cardioprotection.

Cell therapy prevents structural, functional and molecular remodeling of remote non-infarcted myocardium

Background/objectives: Therapy using bone marrow (BM) cells has been tested experimentally and clinically due to the potential ability to restore cardiac function by regenerating lost myocytes or increasing the survival of tissues at risk after myocardial infarction (MI). In this study we aimed to evaluate whether BM-derived mononuclear cell (MNC) implantation can positively influence the post-MI structural remodeling, contractility and Ca(2 +)-handling proteins of the remote non-infarcted tissue in rats. Methods and results: After 48 h of MI induction, saline or BM-MNC were injected. Six weeks later, MI scars were slightly smaller and thicker, and cardiac dilatation was just partially prevented by cell therapy. However, the cardiac performance under hemodynamic stress was totally preserved in the BM-MNC treated group if compared to the untreated group, associated with normal contractility of remote myocardium as analyzed in vitro. The impaired post-rest potentiation of contractile force, associated with decreased protein expression of the sarcoplasmic reticulum Ca2 +-ATPase and phosphorylated-phospholamban and overexpression of Na(+)/Ca(2 +) exchanger, were prevented by BM-MNC, indicating preservation of the Ca(2 +) handling. Finally, pathological changes on remodeled remote tissue such as myocyte hypertrophy, interstitial fibrosis and capillary rarefaction were also mitigated by cell therapy. Conclusions: BM-MNC therapy was able to prevent cardiac structural and molecular remodeling after MI, avoiding pathological changes on Ca(2 +)-handling proteins and preserving contractile behavior of the viable myocardium, which could be the major contributor to the improvements of global cardiac performance after cell transplantation despite that scar tissue still exists.

Stem Cells as a therapy for myocardial infarction in animal models

Advances in stem cell biology have challenged the notion that infarcted myocardium is irreparable. The pluripotent ability of stem cells to differentiate into specialized cell lines began to garner intense interest within cardiology when it was shown in animal models that intramyocardial injection of bone marrow stem cells (MSCs), or the mobilization of bone marrow stem cells with spontaneous homing to myocardium, could improve cardiac function and survival after induced myocardial infarction (MI) [1, 2]. Furthermore, the existence of stem cells in myocardium has been identified in animal heart [3, 4], and intense research is under way in an attempt to clarify their potential clinical application for patients with myocardial infarction. To date, in order to identify the best one, different kinds of stem cells have been studied; these have been derived from embryo or adult tissues (i.e. bone marrow, heart, peripheral blood etc.). Currently, three different biologic therapies for cardiovascular diseases are under investigation: cell therapy, gene therapy and the more recent “tissue-engineering” therapy . During my Ph.D. course, first I focalised my study on the isolation and characterization of Cardiac Stem Cells (CSCs) in wild-type and transgenic mice and for this purpose I attended, for more than one year, the Cardiovascular Research Institute of the New York Medical College, in Valhalla (NY, USA) under the direction of Doctor Piero Anversa. During this period I learnt different Immunohistochemical and Biomolecular techniques, useful for investigating the regenerative potential of stem cells. Then, during the next two years, I studied the new approach of cardiac regenerative medicine based on “tissue-engineering” in order to investigate a new strategy to regenerate the infracted myocardium. Tissue-engineering is a promising approach that makes possible the creation of new functional tissue to replace lost or failing tissue. This new discipline combines isolated functioning cells and biodegradable 3-dimensional (3D) polymeric scaffolds. The scaffold temporarily provides the biomechanical support for the cells until they produce their own extracellular matrix. Because tissue-engineering constructs contain living cells, they may have the potential for growth and cellular self-repair and remodeling. In the present study, I examined whether the tissue-engineering strategy within hyaluron-based scaffolds would result in the formation of alternative cardiac tissue that could replace the scar and improve cardiac function after MI in syngeneic heterotopic rat hearts. Rat hearts were explanted, subjected to left coronary descending artery occlusion, and then grafted into the abdomen (aorta-aorta anastomosis) of receiving syngeneic rat. After 2 weeks, a pouch of 3 mm2 was made in the thickness of the ventricular wall at the level of the post-infarction scar. The hyaluronic scaffold, previously engineered for 3 weeks with rat MSCs, was introduced into the pouch and the myocardial edges sutured with few stitches. Two weeks later we evaluated the cardiac function by M-Mode echocardiography and the myocardial morphology by microscope analysis. We chose bone marrow-derived mensenchymal stem cells (MSCs) because they have shown great signaling and regenerative properties when delivered to heart tissue following a myocardial infarction (MI). However, while the object of cell transplantation is to improve ventricular function, cardiac cell transplantation has had limited success because of poor graft viability and low cell retention, that’s why we decided to combine MSCs with a biopolimeric scaffold. At the end of the experiments we observed that the hyaluronan fibres had not been substantially degraded 2 weeks after heart-transplantation. Most MSCs had migrated to the surrounding infarcted area where they were especially found close to small-sized vessels. Scar tissue was moderated in the engrafted region and the thickness of the corresponding ventricular wall was comparable to that of the non-infarcted remote area. Also, the left ventricular shortening fraction, evaluated by M-Mode echocardiography, was found a little bit increased when compared to that measured just before construct transplantation. Therefore, this study suggests that post-infarction myocardial remodelling can be favourably affected by the grafting of MSCs delivered through a hyaluron-based scaffold

Studio della funzione cardiaca e della massa ventricolare sinistra mediante ecocardiografia convenzionale e tissue doppler imaging in una popolazione pediatrica con malattia renale cronica in terapia conservativa e sostitutiva

Background: Cardiovascular disease (CVD) is a common cause of morbidity and mortality in childhood chronic kidney disease (CKD). Left ventricular hypertrophy (LVH) is known to be one of the earliest events in CVD development. Left ventricular diastolic function (DF) is thought to be also impaired in children with CKD. Tissue Doppler imaging (TDI) provide an accurate measure of DF and is less load dependent than conventional ECHO. Aim: To evaluate the LV mass and the DF in a population of children with CKD. Methods: 37 patients, median age: 10.4 (3.3-19.8); underlying renal disease: hypo/dysplasia (N=28), nephronophthisis (N=4), Alport (N=2), ARPKD (N=3), were analyzed. Thirty-eight percent of the patients were on stage 1-2 of CKD, 38% on stage 3, 16% on stage 4. Three patients were on dialysis. The most frequent factors related to CVD in CKD have been studied. LVH has been defined as a left ventricular mass index (LVMI) more than 35.7 g/h2,7. Results: Twenty-five patients (81%) had a LVH. LVMI and diastolic function index (E’/A’) were significantly related to the glomerular filtration rate (p<0.003 and p<0.004). Moreover the LVMI was correlated with the phosphorus and the hemoglobin level (p<0.0001 and p<0.004). LVH was present since the first stages of CKD (58% of patients were on stages 1-2). Early-diastolic myocardial velocity was reduced in 73% of our patients. We didn’t find any correlation between LVH and systemic hypertension. Conclusion: ECHO evaluation with TDI is suggested also in children prior to dialysis and with a normal blood pressure. If LVH is diagnosed, a periodic follow-up is necessary with the treatment of the modifiable risk factors (hypertension, disturbances of calcium, phosphorus and PTH, anemia ).

Studio longitudinale della funzione cardiaca materna nelle gravidanze gemellari

Obiettivo: studio longitudinale di una coorte di gravidanze gemellari e valutazione di eventuali correlazioni tra specifici parametri cardiaci materni ed esito sfavorevole della gravidanza. Metodi: Sono state arruolate in modo prospettico donne con gravidanze gemellari, sottoposte a controlli seriati della funzione cardiaca materna ( 20-23 settimane; 26-29 settimane e 30-33 settimane). Le pazienti in cui il parto si è verificato prima della 34°settimana compiuta di gestazione sono state escluse a priori dallo studio. Specifici parametri cardiaci campionati sono stati confrontati tra il gruppo di gravidanze con esito positivo ed il gruppo di pazienti che hanno sviluppato complicanze nel corso della gravidanza quali: preeclampsia o ipertensione gestazionale, basso peso alla nascita ( SGA: peso neonatale di uno o entrambi i feti < 5° centile per l’epoca di gestazione). Risultati: sono state incluse nello studio 28 gravidanze gemellari,di cui 8 complicate. Durante ogni visita abbiamo osservato un aumento significativo della gittata cardiaca ( CO ) e sistolica ( SV ) ed una caduta delle resistenze vascolari totali ( TVR ) nelle gravidanze gemellari normali vs complicate. Inoltre, CO, pressione arteriosa (BP), frequenza cardiaca ( HR ) e TVR son rimaste invariate nel corso dei controlli ambulatoriali per le gravidanze con esiti sfavorevole, mentre mostravano modificazioni significative ( CO, HR e BDP in aumento; TVR in diminuzione ) nel gruppo di pazienti con esito favorevole della gravidanza. Conclusioni: La valutazione longitudinale della funzione cardiaca materna sembra dimostrare una significativa differenza tra i valori dei parametri cardiaci materni delle gravidanze multiple non complicate, rispetto a quelle complicate da preeclampsia o neonati SGA.

Utilzzo dei parametri ecocardiografici tradizionali ed a Doppler tissutale nella valutazione della disfunzione atrio-ventricolare in cani affetti da malattia mitralica cronica

In questo lavoro ci siamo posti come obiettivo lo studio della disfunzione atrio-ventricolare mediante tecniche ecocardiografiche avanzate (come il Tissue Doppler Imaging - TDI) in cani affetti da malattia mitralica cronica (MVD). Una prima parte è volta alla valutazione della funzionalità diastolica del ventricolo destro. Ci siamo proposti di analizzare la funzione del ventricolo destro in cani affetti da malattia del cuore sinistro per comprendere se quest’ultima possa condizionare direttamente la performance del settore cardiaco controlaterale. I risultati più importanti che abbiamo riscontrato sono: l’assenza di differenze significative nella disfunzione sisto-diastolica del ventricolo destro in cani con MVD a diverso stadio; la diretta correlazione tra le variabili TDI di funzionalità del ventricolo destro con il grado di disfunzione del ventricolo sinistro, come indicatori di interdipendenza ventricolare; ed infine il riscontro di una maggior tendenza ad alterazioni diastoliche del ventricolo sinistro in cani con ipertensione polmonare. A quest’ultimo proposito, per quanto riguarda le variabili TDI, il rapporto E/e’ dell’anulus mitralico laterale e settale è risultato avere una differenza significativa tra i cani con ipertensione polmonare e quelli privi di ipertensione polmonare (P<0,01). Nel secondo studio abbiamo applicato il TDI per l’analisi della funzione sisto-diastolica dell’atrio sinistro. Il lavoro è stato articolato in una parte di validazione della metodica su cani normali ed una su animali affetti da MDV. I risultati ottenuti mostrano che la valutazione ecocardiografica delle proprietà di deformazione dell’atrio sinistro basata sul TDI è attuabile e riproducibile nel cane. Abbiamo fornito dei valori di normalità per questa specie e confrontato questi dati con quelli ricavati in cani portatori di MVD. Le differenza tra le varie classi di malattia, nei diversi gradi di dilatazione atriale, sono risultate limitate, ma abbiamo individuato delle correlazioni tra i parametri TDI ed alcune variabili di funzionalità atriale.

Wirkung und Interaktion der Wachstumsfaktoren Myostatin und IGF-1 im murinen Herzen

Myostatin, ein Mitglied der TGF-β Familie von Wachstumsfaktoren, ist ein negativer Regulator des Skelettmuskelwachstums. Obwohl Myostatin nach einer Vielzahl pathologischer Zustände im Herzen massiv hochreguliert wird, ist die physiologische und pathophysiologische Funktion von Myostatin im Herzen noch kaum erforscht. Deshalb wurde im Rahmen dieser Dissertation die Funktion von Myostatin im adulten Herzen untersucht. Dazu wurden Mausmodelle, in denen Myostatin in Kardiomyozyten deletiert und überexprimiert wird, verwendet. Ich konnte zeigen, dass die akute Deletion von Myostatin in Kardiomyozyten zu einer erhöhten Lethalität, Herzinsuffizienz und Hypertrophie führt. Dabei konnte ich eine Aktivierung der AMP-aktivierten Kinase (AMPK) als Ursache der Hypertrophie identifizieren und mit Hilfe eines AMPK Inhibitors die Entstehung der Hypertrophie in vivo verhindern. Des Weiteren konnte ich in vivo und in vitro zeigen, dass Myostatin AMPK über die TGF-β-aktivierte Kinase 1 (TAK1) und seinen kanonischen Rezeptor inhibiert. Die akute Deletion von Myostatin hemmte auch die Expression von Rgs2, einem Inhibitor der Gq Signalkaskade, und führte dadurch zu einer Aktivierung dieses für Herzinsuffizienz elementaren Signalweges. Außerdem verbesserte die akute adulte Überexpression von Myostatin die Herzkontraktilität leicht, während eine langfristige Überexpression eine interstitielle Fibrose, die über TAK1 und p38 vermittelt wird, induzierte. Hiermit konnte ich Myostatin als neuen Regulator der Hypertrophie und Herzinsuffizienz etablieren.rn