Maria José Figueiredo

The antipyretic effect of dipyrone is unrelated to inhibition of PGE2 synthesis in the hypothalamus

BACKGROUND AND PURPOSE Bacterial lipopolysaccharide (LPS) induces fever through two parallel pathways; one, prostaglandin (PG)‐dependent and the other, PG‐independent and involving endothelin‐1 (ET‐1). For a better understanding of the mechanisms by which dipyrone exerts antipyresis, we have investigated its effects on fever and changes in PGE2 content in plasma, CSF and hypothalamus induced by either LPS or ET‐1.

Inflammatory mediators involved in the nociceptive and oedematogenic responses induced by Tityus serrulatus scorpion venom injected into rat paws.

The present study investigated the role of kinins, prostaglandins (PGs) and nitric oxide (NO) in mechanical hypernociception, spontaneous nociception and paw oedema after intraplantar (ipl) injection of Tityus serrulatus venom (Tsv) in male Wistar rats. Tsv was ipl-injected in doses of 0.01-10microg/paw. Pre-treatment (30min prior) with DALBK (100nmol/paw) and icatibant (10nmol/paw), B1 and B2 selective kinin receptor antagonists, L-NAME (50mg/kg, i.p., a non-selective nitric oxide synthase inhibitor) or celecoxib, selective COX-2 inhibitor, was given 1h prior per os (5mg/kg, p.o.), significantly reduced the hypernociceptive response (Von Frey method), the spontaneous nociception (determined by counting the number of flinches) and paw oedema (plethysmometer method) induced by Tsv at doses of 1.0 and 10microg/paw for both nociceptive and oedematogenic responses, respectively. Nevertheless, indomethacin (5mg/kg, i.p., 30min prior) was ineffective in altering all of these events. The results of the present study show that Tsv, injected ipl into the rat paw, causes a dose-dependent paw oedema, mechanical hypernociception and flinches (a characteristic biphasic response) in which kinins and NO are substantially involved. Although celecoxib was effective against the oedema and pain caused by Tsv, COX-2 does not seem to be involved in the inflammatory response caused by Tsv.

Disruption of Calcium Homeostasis in Cardiomyocytes Underlies Cardiac Structural and Functional Changes in Severe Sepsis

Sepsis, a major cause of morbidity/mortality in intensive care units worldwide, is commonly associated with cardiac dysfunction, which worsens the prognosis dramatically for patients. Although in recent years the concept of septic cardiomyopathy has evolved, the importance of myocardial structural alterations in sepsis has not been fully explored. This study offers novel and mechanistic data to clarify subcellular events that occur in the pathogenesis of septic cardiomyopathy and myocardial dysfunction in severe sepsis. Cultured neonatal mice cardiomyocytes subjected to serum obtained from mice with severe sepsis presented striking increment of [Ca2+]i and calpain-1 levels associated with decreased expression of dystrophin and disruption and derangement of F-actin filaments and cytoplasmic bleb formation. Severe sepsis induced in mice led to an increased expression of calpain-1 in cardiomyocytes. Moreover, decreased myocardial amounts of dystrophin, sarcomeric actin, and myosin heavy chain were observed in septic hearts associated with depressed cardiac contractile dysfunction and a very low survival rate. Actin and myosin from the sarcomere are first disassembled by calpain and then ubiquitinated and degraded by proteasome or sequestered inside specialized vacuoles called autophagosomes, delivered to the lysosome for degradation forming autophagolysosomes. Verapamil and dantrolene prevented the increase of calpain-1 levels and preserved dystrophin, actin, and myosin loss/reduction as well cardiac contractile dysfunction associated with strikingly improved survival rate. These abnormal parameters emerge as therapeutic targets, which modulation may provide beneficial effects on future vascular outcomes and mortality in sepsis. Further studies are needed to shed light on this mechanism, mainly regarding specific calpain inhibitors.

CCL3/MIP-1α is not involved in the LPS-induced fever and its pyrogenic activity depends on CRF

The fever induced by lipopolysaccharide (LPS) depends on both prostaglandin-dependent and -independent pathways. One of the prostaglandin-independent pathways is sequentially orchestrated by pre-formed pyrogenic factor derived from LPS-stimulated macrophages (PFPF), corticotrophin releasing factor (CRF), endothelin-1 (ET-1) and interleukin-1 (IL-1). As macrophage-inflammatory-protein (MIP)-1 alpha (synonym CCL3) also induces a prostaglandin independent fever, the aim of the present study was to investigate a possible participation of CCL3/MIP-1 alpha within the prostaglandin-independent pathway of LPS-induced fever which depends on PFPF, CRF and ET-1. Therefore, rats received intracerebroventricular (i.c.v.) pre-treatment with anti-CCL3 monoclonal antibody (1 and 5 ng) at 1 h and 15 min before injection of LPS (lipopolysaccharide from E. coli; 5, 50 or 100 microg kg(-1), i.v.) or CCL3/MIP-1 alpha (500 pg, i.c.v.). Both doses of anti-CCL3 did not change the basal temperature but abolished the fever induced by CCL3/MIP-1 alpha. When given at the higher dose, anti-CCL3 did not influence the fever induced by i.v. injection of different doses of LPS, or i.c.v. administration of PFPF (200 ng), CRF (3 microg) or ET-1 (1 pmol). Bosentan, a non-selective ET(A/B) receptors antagonist (10 microg kg(-1), i.v.), reduced the fever induced by LPS but not that induced by CCL3/MIP-1 alpha. In contrast, alpha-helical CRF(9-41) (a non-selective CRF R1/R2 receptor antagonist; 25 microg injected i.c.v.) reduced CCL3/MIP-1 alpha-induced fever. In conclusion, the present results indicate that: i) CCL3/MIP-1 alpha is not an endogenous mediator of LPS-induced fever; ii) it is even not involved in the prostaglandin-independent pathway of the LPS-fever cascade and iii) its pyrogenic activity depends on synthesis/release of CRF.

Inflammatory mediators involved in the paw edema and hyperalgesia induced by Batroxase, a metalloproteinase isolated from Bothrops atrox snake venom

Snake venom metalloproteinases have been described as responsible for several inflammatory effects. In this study, we investigated the edema and hyperalgesia induced in rats by Batroxase, a P-I metalloproteinase from Bothrops atrox venom, along with possible inflammatory mediators involved in these responses. Batroxase or sterile saline was injected into rat paws and the edema and hyperalgesic effects were evaluated for 6h by using a plethysmometer and a Von Frey system, respectively. Batroxase induced significant edematogenic and hyperalgesic peak responses in the first hours after administration. The inflammatory mediators involved in these responses were assayed by pretreatment of animals with synthesis inhibitors or receptor antagonists. Peak responses were significantly reduced by administration of the glucocorticoid dexamethasone, the H1 receptor antagonist diphenhydramine and the FLAP inhibitor MK-886. Rat paws injected with compound 48/80, a mast cell degranulating agent, followed by Batroxase injection resulted in significant reduction of the edema and hyperalgesia. However, Batroxase itself induced minor degranulation of RBL-2H3 mast cells in vitro. Additionally, the inflammatory responses did not seem to be related to prostaglandins, bradykinin or nitric oxide. Our results indicate a major involvement of histamine and leukotrienes in the edema and hyperalgesia induced by Batroxase, which could be related, at least in part, to mast cell degranulation.

Increase of core temperature induced by corticotropin-releasing factor and urocortin: A comparative study

This study compared the ability of CRF and UCN1 to induce a thermoregulatory response when centrally injected into rats. The effects of antipyretic drugs and CRF receptor antagonists (CRF₁ and CRF₂) on the temperature (T) changes induced by these peptides were also investigated. Rectal (rT) and tail skin (T(sk)) temperatures were measured with a thermistor probe while body (bT) temperature was measured with a battery-operated biotelemetry transmitter in male Wistar rats (200 g) every 30 min over a period of 6h, after intracerebroventricular (i.c.v.) injection of 1 nmol of either CRF or UCN1. Rats were pre-treated with indomethacin (2 mg kg⁻¹, i.p.) or celecoxib (5 mg kg⁻¹, p.o.), dexamethasone (0.5 mg kg⁻¹, s.c.), astressin (a CRF₁/CRF₂ antagonist, 7 nmol, i.c.v.) or antalarmin (a CRF₁ antagonist, 20 mg kg⁻¹, i.p.). The increase in body temperature induced by CRF was accompanied by a reduction in T(sk) while the response induced by UCN1 was accompanied by an elevation in T(sk). Indomethacin or celecoxib did not change the increases in rT caused by either CRF or UCN1. Although dexamethasone attenuated the increase in rectal temperature in response to CRF, dexamethasone did not modify the response induced by UCN1. Astressin blocked the UCN1-induced hyperthermia and reduced CRF-induced fever. Antalarmin did not modify the hyperthermia in response to UCN1, but reduced the fever evoked by CRF. This study demonstrated that CRF by acting on the CRF₁ receptor induces a prostaglandin-independent fever which seems to depend, at least in part, on the synthesis of other mediators while UCN1 acts on the CRF₂ receptor, promoting a hyperthermic response which seems to be independent on synthesis/release of any mediator.

Cytokines, but not corticotropin-releasing factor and endothelin-1, participate centrally in the febrile response in zymosan-induced arthritis in rats.

Recent literature has revealed that centrally generated prostaglandins participate in the febrile response in zymosan-induced arthritis in rats. However, it is not clear whether other centrally acting pyrogenic mediators such as cytokines, endothelins (ETs), and the corticotropin-releasing factor (CRF) contribute to the febrile response in this model. In the present study, rats were pretreated with intracerebroventricular (i.c.v.) injections of soluble TNF receptor I (sTNFRI), recombinant IL-1 receptor antagonist (IL-1ra), anti-rat IL-6 monoclonal antibody (AbIL-6), α-helical CRF9-41 (a nonselective CRF1/CRF2 receptor antagonist), BQ-123 (an ETA receptor antagonist), BQ-788 (an ETB receptor antagonist), and artificial cerebrospinal fluid (aCSF, control) prior to an intra-articular zymosan (4 mg) injection. Rectal temperatures were measured with a telethermometer. The administration of IL-1ra (200 µg), sTNFRI (500 ng), and AbIL-6 (5 µg) attenuated body temperature elevations after a zymosan injection. The administration of BQ-788 (3 pmol), BQ-123 (3 pmol), and α-helical CRF9-41 (25 µg) did not affect the zymosan-induced febrile response. All the compounds used to pretreat the animals did not significantly alter their basal body temperatures. Together, the results here demonstrate that the febrile response in zymosan-induced arthritis in rats depends on the centrally acting pyrogenic cytokines TNF-α, IL-1β, and IL-6, but does not depend on either CRF or ET-1.

Involvement of PGE2 and RANTES in Staphylococcus aureus-induced fever in rats

This study investigated the involvement of prostaglandins and regulated on activation, normal T cell expressed and secreted (RANTES), in fever induced by live Staphylococcus aureus (no. 25923, American Type Culture Collection) injection in rats. S. aureus was injected intraperitoneally at 10(9), 10(10), and 2 × 10(10) colony-forming units (CFU)/cavity, and body temperature (T(b)) was measured by radiotelemetry. The lowest dose of S. aureus induced a modest transient increase in T(b), whereas the two higher doses promoted similar long-lasting and sustained T(b) increases. Thus, the 10(10) CFU/cavity dose was chosen for the remaining experiments. The T(b) increase induced by S. aureus was accompanied by significant decreases in tail skin temperature and increases in PGE(2) levels in the cerebrospinal fluid (CSF) and hypothalamus but not in the venous plasma. Celecoxib (selective cyclooxygenase-2 inhibitor, 2.5 mg/kg po) inhibited the fever and the increases in PGE(2) concentration in the CSF and hypothalamus induced by S. aureus. Dipyrone (120 mg/kg ip) reduced the fever from 2.5 to 4 h and the PGE(2) increase in the CSF but not in the hypothalamus. S. aureus increased RANTES in the peritoneal exudate but not in the CSF or hypothalamus. Met-RANTES (100 μg/kg iv), a chemokine (C-C motif) receptor (CCR)1/CCR5 antagonist, reduced the first 6 h of fever induced by S. aureus. This study suggests that peripheral (local) RANTES and central PGE(2) production are key events in the febrile response to live S. aureus injection. As dipyrone does not reduce PGE(2) synthesis in the hypothalamus, it is plausible that S. aureus induces fever, in part, via a dipyrone-sensitive PGE(2)-independent pathway.

Activation of both the calpain and ubiquitin-proteasome systems contributes to septic cardiomyopathy through dystrophin loss/disruption and mTOR inhibition

Cardiac dysfunction caused by the impairment of myocardial contractility has been recognized as an important factor contributing to the high mortality in sepsis. Calpain activation in the heart takes place in response to increased intracellular calcium influx resulting in proteolysis of structural and contractile proteins with subsequent myocardial dysfunction. The purpose of the present study was to test the hypothesis that increased levels of calpain in the septic heart leads to disruption of structural and contractile proteins and that administration of calpain inhibitor-1 (N-acetyl-leucinyl-leucinyl-norleucinal (ALLN)) after sepsis induced by cecal ligation and puncture prevents cardiac protein degradation. We also tested the hypothesis that calpain plays a role in the modulation of protein synthesis/degradation through the activation of proteasome-dependent proteolysis and inhibition of the mTOR pathway. Severe sepsis significantly increased heart calpain-1 levels and promoted ubiquitin and Pa28β over-expression with a reduction in the mTOR levels. In addition, sepsis reduced the expression of structural proteins dystrophin and β-dystroglycan as well as the contractile proteins actin and myosin. ALLN administration prevented sepsis-induced increases in calpain and ubiquitin levels in the heart, which resulted in decreased of structural and contractile proteins degradation and basal mTOR expression levels were re-established. Our results support the concept that increased calpain concentrations may be part of an important mechanism of sepsis-induced cardiac muscle proteolysis.

Calpain-1 inhibitor prevent loss of dystrophin in experimental septic cardiomyopathy induced by cecal ligation and puncture (CLP)

Objective: The small incisions of minimally invasive surgery have the proposed benefits of less surgical trauma, less pain, and an improved cosmetic outcome; all of which correspond to a faster postoperative recovery. Opponents claim smaller incisions lead to poor exposure, making the operation longer, more difficult and dangerous. Here, we report our experience performing minimally invasive aortic valve replacements, via a minimally invasive anterior thoracotomy or mini-sternotomy approach, in comparison to conventional sternotomy.AIMS To evaluate the efficacy of a unique healthy and happy lifestyle (HLS) program in regression of coronary atherosclerosis and reduction in cardiac events in an open trial. METHODS One hundred and twenty three angiographically documented moderate to severe coronary artery disease (CAD) patients were administered HLS comprising of low-fat, high-fiber vegetarian diet, moderate aerobic exercise and stress-management through Rajyoga meditation. Its most salient feature was training in self-responsibility (heal+thy) and self-empowerment through inner-self consciousness (swasth; swa=innerself, sth=consciousness) approach using Rajyoga meditation. Following a seven day in-house sojourn, patients were invited for six month follow-up for reassessment and advanced training. At the end of two years, all patients were asked to undergo repeat angiography. RESULTS Three hundred and sixty coronary lesions were analysed by two independent angiographers. In CAD patients with most adherence, percent diameter stenosis regressed by 18.23 +/- 12.04 absolute percentage points. 91% patients showed a trend towards regression and 51.4% lesions regressed by more than 10 absolute percentage points. The cardiac events in coronary artery disease patients were: 11 in most adherence, and 38 in least adherence over a follow-up period of 6.48 yrs. (risk ratio; most vs least adherence: 4.32; 95% CI: 1.69-11.705; P < 0.002). CONCLUSION Overall healthy changes in cardiovascular, metabolic and psychological parameters, decline in absolute percent diameter coronary stenosis and cardiac events in patients of CAD were closely related to HLS adherence. However, more than 50% adherence is essential to achieve a significant change.Introduction: Despite major advancements in coronary revascularization therapy, including percutaneous coronary intervention and coronary artery bypass grafting, many patients are ineligible for interventional therapy or remain symptomatic despite optimal treatment. For this group of patients, pain often significantly limits physical activity and contributes to a poor quality of life. Spinal cord stimulation (SCS) has been described as a potential safe and effective treatment modality for this select group of patients.Segmental contractions were quantified from images of electrocardiographic-gated single-photon emission computed tomography. Counts were integrated in 64 angles about the centre on short-axis images and projected onto a cylindrical screen. Changes in the projected count were shown to obey the equation of continuity for two-dimensional fluids (the Poisson equation). Displacements of each pixel point were calculated from the velocity field to quantify the amount of dislocation. Changes in the configuration of the pixel points were projected back on the cardiac wall, and finally segmental contractions were evaluated as a percentage reduction of the area. Computer simulations were performed for numerical models of circumferential and long-axial contractions, uneven eccentric contractions and rotations. These models were blurred with a three-dimensional Gaussian function. The results obtained using this method (quantification of segmental function by solving the Poisson equation (QSFP)) were compared with the wall-thickening method (WTM) and the maximum-count method. Both QSFP and WTM yielded good agreement with predicted values for circumferential and long-axial contractions. Only QSFP gave satisfactory results for uneven eccentric contractions, and rotation models. QSFP should provide a useful tool for in vivo quantification of contraction tangential to the cardiac wall by eliminating errors due to displacements.I is difficult to study the effect of cigarette smoke on humans in a systematic way; therefore, we studied the effect of cigarette smoke exposure on cardiac transplant survival and the development of myocardial infarction in rat models. In this experimental study, we investigated early consequences of tobacco smoke exposure in cardiac transplant donors and recipients with an emphasis on alloinflammatory mediators of graft outcome using heterotopic rat cardiac transplantation; we tested the effects of donor or recipient tobacco smoke exposure. Our experiments reveal that pre-transplantation tobacco exposure in donors and/or recipients results in heightened systemic inflammation and increased oxidative stress reduces post-transplantation cardiac allograft survival. Our studies with cigarettes without nicotine demonstrated significantly lesser detrimental effects on cardiac transplant survival.N oxide (NO) is a multifunctional signaling molecule, intricately involved with maintaining a host of physiological processes including but not limited to host defense, neuronal communication and the regulation of vascular tone. The endothelium-derived NO plays a crucial role in regulating a wide spectrum of functionsin the cardiovascular system, including vasorelaxation, inhibition of leukocyte-endothelial adhesion, vascular smooth muscle cell (SMC) migration and proliferation, as well as platelet aggregation. In this regard, NO is a potent vasodilator as well as a powerful anti-platelet and anti-leukocyte factor. NO is one of the most important signaling molecules in our body. Loss of NO function is one of the earliest indicators or markers of disease. Experimental and clinical studies provide evidence that defects of endothelial NO production, referred to as endothelial dysfunction, is not only associated with all major cardiovascular risk factors such as hyperlipidemia, diabetes, hypertension, erectile dysfunction, smoking and severity of atherosclerosis, but also has a profound predictive value for future atherosclerotic disease progression. Emerging published literature reveals that NO insufficiency may manifest itself differently in different patients. Thirty plus years after its discovery and over 14 years since a Nobel Prize was awarded for its discovery, there have been no hallmark therapeutic breakthroughs. We will review the current state of the science surrounding nitric oxide in the etiology of a number of different disease states and reveal the latest technology to safely and effectively restore nitric oxide in patients. The audience will learn the challenges and opportunities that exist in understand NO homeostasis in their patients and how this may translate into better management of their patients.BACKGROUND It has been recently reported that inflammatory mechanisms play an important role in in-stent restenosis (ISR) processes. Inflammatory factors after percutaneous coronary intervention (PCI) for dynamic monitoring can probably predict ISR. Functional polymorphisms in the promoter region of genes coding for inflammatory factors might be important for determining the magnitude of the inflammatory response. Thus, in the present study, we aimed to investigate the serial changes in serum interleukin-6 (IL-6) levels before and after PCI and the relationship between the -572C/G polymorphism in the promoter region of the IL-6 gene and ISR. We also discussed genetic polymorphisms in the inflammatory response to PCI. METHODS A total of 437 patients who successfully underwent bare metal stent (BMS) implantation with a follow-up angiography were divided into an ISR group (n = 166) and a non-ISR (NISR) group (n = 271). The IL-6 gene promoter polymorphism at position -572 was determined by restricted fragment length polymorphism using the polymerase chain reaction (PCR-RFLP) method. The serum IL-6 levels before and one day, five days and 180 days after PCI were determined by the radioimmunoassay method. RESULTS ISR patients showed higher IL-6 serum levels than NISR patients before PCI ((324.42 ± 28.14) ng/L vs. (283.22 ± 47.30) ng/L, P < 0.001), and one day post-PCI IL-6 serum levels in the ISR group also showed a significantly higher level than in the NISR group (P < 0.001). Increased IL-6 after PCI persisted at a statistically significant level throughout the study in ISR patients, whereas IL-6 levels had normalized five days after the procedure in NISR patients. One day post-PCI serum IL-6 level was the most accurate marker for diagnosis of ISR, the area under the ROC curve being 0.927 (95%CI 0.878 - 0.977). The cut-off value for IL-6 to predict ISR was over 355.50 ng/L, with a sensitivity of 0.968 and a specificity of 0.865. There were no significant differences in frequencies of -572 genotype and allele between the two groups (P > 0.05). One day post-PCI IL-6 serum levels in patients with the G allele was significantly higher than in patients without the G allele ((366.99 ± 49.37) ng/L vs. (347.20 ± 55.30) ng/L, P < 0.05). In the ISR group, one day post-PCI serum levels of IL-6 in patients with the G allele was also significantly higher than that in patients without the G allele ((405.67 ± 26.56) ng/L vs. (375.69 ± 38.81) ng/L, P < 0.05). Multivariate Logistic regression analysis revealed positive correlations between male gender, one day post-PCI serum levels of IL-6, the pre-PCI degree of stenosis, the length of the target lesion stenosis, and restenosis; and there were negative correlations between the stent diameter, the diameter of the reference vessel before stent implantation and restenosis. CONCLUSIONS IL-6 is an early post-PCI inflammatory cytokine, and one day post-PCI serum IL-6 level is an independent risk factor for restenosis. The frequencies of IL-6 gene -572 genotype and allele are not different between patients with and without ISR in a Chinese Tianjin Han population, but carrying the IL-6 -572G allele is likely to increase an individuals susceptibility to ISR by promoting serum IL-6 levels.Background: Propofol is an anesthetic drug with a very attractive pharmacokinetic profile, which makes it the induction agent of choice, especially in day-case surgery. Data on its potential proarrhythmic effects in patients with Brugada syndrome (BS) patients are still lacking. The aim of our study was to investigate whether a single dose of propofol triggered any adverse events in consecutive high-risk patients with BS.Intact heart muscles are believed to contract synchronously to produce maximum effective work at a minimum energy cost. Temporal correlation coefficients between the left ventricular volume and muscle contraction were introduced to assess the synchronicity of left ventricular contraction (synchronous contraction index, SCI), and applied to eight normal volunteers. Area-contraction and length-shortening parallel to and perpendicular to the long axis were computed from electrocardiogram (ECG)-gated single-photon emission computed tomographies (SPECT) using a homemade computer programme. The cardiac wall was divided into nine segments, and the average values of accumulation of perfusion agents, amplitude of contraction and SCI were obtained in each segment. The area-SCI was 91.4% +/- 4.3% and relatively uniform over the whole cardiac wall (p = 0.014, analysis of variance (ANOVA)), whereas the accumulation and amplitude of contraction varied significantly in different segments (p < 0.0001, ANOVA). This study suggested that in normal subjects the myocardial contraction was synchronous, and that the amplitude of contraction was not spatially uniform.