Subchronic toxicity and anti-HSV-1 activity in experimental animal of dolabelladienetriol from the seaweed, Dictyota pfaffii.

This study examined in rats the subchronic toxicity and anti- HSV-1activity after oral administration of dolabelladienetriol (D1), a diterpene isolated from the seaweed Dictyota pfaffii. In subchronic toxicity (SCT) tests, female rats received D1 by gavage 15 mg/kg/day (n = 5) for 50 days, and general behavior, death, hematological, biochemical and histological changes in the liver, kidney, stomach, and duodenum were determined. For the anti-HSV-1 activity, female mice were infected and treated orally with a dose of 20 mg/kg (n = 5) twice a day with D1 and any lesions in the skin were then recorded for 18 days. Dolabelladienetriol in SCT did not significantly change behavior, body weight, hematological or biochemical profiles. The liver and kidneys, however, showed some alterations in rats treated with D1, similar to those in rats treated with ACV, while the other tissues had no significant changes. The anti-HSV-1 activity of D1 had a similar efficacy to the ACV drug control in mice. Our results showed that D1 has potential commercial development as a new HSV-1drug.

Sarcoplasmic reticulum and calcium signaling in muscle cells: Homeostasis and disease.

The sarco/endoplasmic reticulum is an extensive, dynamic and heterogeneous membranous network that fulfills multiple homeostatic functions. Among them, it compartmentalizes, stores and releases calcium within the intracellular space. In the case of muscle cells, calcium released from the sarco/endoplasmic reticulum in the vicinity of the contractile machinery induces cell contraction. Furthermore, sarco/endoplasmic reticulum-derived calcium also regulates gene transcription in the nucleus, energy metabolism in mitochondria and cytosolic signaling pathways. These diverse and overlapping processes require a highly complex fine-tuning that the sarco/endoplasmic reticulum provides by means of its numerous tubules and cisternae, specialized domains and contacts with other organelles. The sarco/endoplasmic reticulum also possesses a rich calcium-handling machinery, functionally coupled to both contraction-inducing stimuli and the contractile apparatus. Such is the importance of the sarco/endoplasmic reticulum for muscle cell physiology, that alterations in its structure, function or its calcium-handling machinery are intimately associated with the development of cardiometabolic diseases. Cardiac hypertrophy, insulin resistance and arterial hypertension are age-related pathologies with a common mechanism at the muscle cell level: the accumulation of damaged proteins at the sarco/endoplasmic reticulum induces a stress response condition termed endoplasmic reticulum stress, which impairs proper organelle function, ultimately leading to pathogenesis.

The serum D-xylose test as a useful tool to identify malabsorption in rats with antigen specific gut inflammatory reaction.

The inappropriate immune response to foods, such as peanut, wheat and milk may be the basis in the pathogenesis of enteropathies like coeliac and Crohn disease, which present small intestinal malabsorption. A number of recent studies have utilized d-xylose absorption as an investigative tool to study small intestinal function in a variety of clinical settings. Thus, the aim of this experimental study was to evaluate the intestinal absorption of D-xylose in an antigen-specific gut inflammatory reaction rat model. Animals of the experimental group were inoculated with peanut protein extract before their exposure to a challenge diet containing exclusively peanut seeds to induce the gut inflammatory reaction caused by peanut allergy. Our results show that systemic inoculation with peanut protein extract renders significantly higher antibody titres (5.085 +/- 0.126 units) (P < 0.0001) than control rats (0.905 +/- 0.053 units) and that the antibody titres correlate positively to an inflammatory alteration of the gut morphology (P < 0.0001). Animals pertaining to the experimental group showed an intestinal absorption of D-xylose lower than control rats (P < 0.0001). We also observed that D-xylose absorption correlates negatively with IgG titres and positively with morphometric parameters (Pearson correlation). In conclusion, the use of serum D-xylose test was useful to identify the presence of small intestinal malabsorption in our antigen specific gut inflammatory reaction rat model.

Synthesis, antiviral activity and molecular modeling of oxoquinoline derivatives.

In the present article, we describe the synthesis, anti-HIV1 profile and molecular modeling evaluation of 11 oxoquinoline derivatives. The structure-activity relationship analysis revealed some stereoelectronic properties such as LUMO energy, dipole moment, number of rotatable bonds, and of hydrogen bond donors and acceptors correlated with the potency of compounds. We also describe the importance of substituents R(2) and R(3) for their biological activity. Compound 2j was identified as a lead compound for future investigation due to its: (i) high activity against HIV-1, (ii) low cytotoxicity in PBMC, (iii) low toxic risks based on in silico evaluation, (iv) a good theoretical oral bioavailability according to Lipinski 'rule of five', (v) higher druglikeness and drug-score values than current antivirals AZT and efavirenz.

Herpud1 negatively regulates pathological cardiac hypertrophy by inducing IP3 receptor degradation.

Cardiac hypertrophy is an adaptive response triggered by pathological stimuli. Regulation of the synthesis and the degradation of the Ca2+ channel inositol 1,4,5-trisphosphate receptor (IP3R) affects progression to cardiac hypertrophy. Herpud1, a component of the endoplasmic reticulum-associated degradation (ERAD) complex, participates in IP3R1 degradation and Ca2+ signaling, but the cardiac function of Herpud1 remains unknown. We hypothesize that Herpud1 acts as a negative regulator of cardiac hypertrophy by regulating IP3R protein levels. Our results show that Herpud1-knockout mice exhibit cardiac hypertrophy and dysfunction and that decreased Herpud1 protein levels lead to elevated levels of hypertrophic markers in cultured rat cardiomyocytes. In addition, IP3R levels were elevated both in Herpud1-knockout mice and Herpud1 siRNA-treated rat cardiomyocytes. The latter treatment also led to elevated cytosolic and nuclear Ca2+ levels. In summary, the absence of Herpud1 generates a pathological hypertrophic phenotype by regulating IP3R protein levels. Herpud1 is a novel negative regulator of pathological cardiac hypertrophy.

Novel Therapies Targeting Cardioprotection and Regeneration.

Cardiovascular disease is the leading cause of death worldwide. The heart is susceptible to pathologies that impact the myocardium directly, such as myocardial infarction and consequent heart failure, as well as conditions with indirect cardiac effects, such as cancer treatment-related cardiotoxicity. As the contractile cells of the heart, cardiomyocytes are essential for normal cardiac function. Various stress stimuli may result in transient damage or cell death in cardiomyocytes through apoptosis, necrosis or maladaptive autophagy. Moreover, cardiomyocytes are unable to regenerate; thus, lost cells are replaced with fibrotic tissue, with a potentially severe impact on myocardial function. Several therapeutic agents and strategies to reduce cardiomyocyte damage are currently available. This manuscript reviews the state of the art regarding novel cardioprotective endogenous peptides, such as neuregulin-1, angiotensin-(1-9), growth/differentiation factor-11, growth/differentiation factor- 15 and insulin-like growth factor-1. We discuss their protective effects and therapeutic potential in cardiovascular diseases and the current challenges to harnessing their full cardioprotective power. We also explore targeting of exosomes as a cardioprotective approach along with the therapeutic potential of cardiac regeneration strategies. Further advances associated with these molecules and cardioprotective approaches may provide more effective therapies to attenuate or prevent cardiomyocyte death, thereby preserving the myocardium.

New Molecular Insights of Insulin in Diabetic Cardiomyopathy.

Type 2 diabetes mellitus (T2DM) is a highly prevalent disease worldwide. Cardiovascular disorders generated as a consequence of T2DM are a major cause of death related to this disease. Diabetic cardiomyopathy (DCM) is characterized by the morphological, functional and metabolic changes in the heart produced as a complication of T2DM. This cardiac disorder is characterized by constant high blood glucose and lipids levels which eventually generate oxidative stress, defective calcium handling, altered mitochondrial function, inflammation and fibrosis. In this context, insulin is of paramount importance for cardiac contractility, growth and metabolism and therefore, an impaired insulin signaling plays a critical role in the DCM development. However, the exact pathophysiological mechanisms leading to DCM are still a matter of study. Despite the numerous questions raised in the study of DCM, there have also been important findings, such as the role of micro-RNAs (miRNAs), which can not only have the potential of being important biomarkers, but also therapeutic targets. Furthermore, exosomes also arise as an interesting variable to consider, since they represent an important inter-cellular communication mechanism and therefore, they may explain many aspects of the pathophysiology of DCM and their study may lead to the development of therapeutic agents capable of improving insulin signaling. In addition, adenosine and adenosine receptors (ARs) may also play an important role in DCM. Moreover, the possible cross-talk between insulin and ARs may provide new strategies to reverse its defective signaling in the diabetic heart. This review focuses on DCM, the role of insulin in this pathology and the discussion of new molecular insights which may help to understand its underlying mechanisms and generate possible new therapeutic strategies.

Food allergy/hypersensitivity: antigenicity or timing?

Mechanisms involved in the induction of oral tolerance (OT) or systemic immunization through the oral rout are still poorly understood. In our previous studies, we have shown that when normal mice eat peanuts they become tolerant, with no gut alterations. Conversely, if immunized with peanut proteins prior to a challenge diet (CD) containing peanuts they develop chronic inflammation of the gut. Our aim is to evaluate the consequences of the introduction of a novel protein in the diet of animals presenting antigen-specific gut inflammation. Adult, female C57BL/6J mice were divided in control (C) and experimental (E) groups. C1-C3 received peanut protein immunization, animals of the control groups C4 were sham immunized, and control group C5 received ovalbumin (OVA) immunization. The experimental group was immunized with peanut protein extract. Before initial exposure to a 30-day peanut containing CD, the experimental group was divided into 5 groups (E1-E5). OVA feeding began 7 days prior CD (E1) on day 0 (E2), 7 (E3), 14 (E4) and 21 (E5) during CD. Our results show that oral exposure to a novel protein (OVA) in the absence of gut inflammation (E1) leads to low levels of systemic antibody (Ab) titers, comparable to tolerant animals. Conversely, as off initial induction of inflammation, groups submitted to OVA (OT) protocol develop increasingly higher systemic Ab titers similar to animals of the immune control group. In conclusion, our protocol indicates that timing is more important than the antigenicity when a novel protein is offered, in the diet.

Therapeutic dose of Ginkgo biloba extract 761 may alter the urine excretion of Wistar rats

Wistar rats (n=20) were divided in two groups: G1 received 2 mg/kg of GBE (Ginkgo biloba extract 761), whereas G2 received the same volume of a sodium chloride solution (0.9%), both for 10 days. After a 7-day interval, the treatment was repeated for 8 days. Urine volume and food and water intake were measured daily during this protocol. Histological assessments were performed. No significant difference (p>0.05) was observed in food and water intake of animals during treatment with GBE. Animals who received GBE had a smaller urine volume and increase of weight with a significance difference (p<0.05) during the first and second exposure period. No histological alteration was observed in tissues, except for the kidney of the experimental group, which revealed a higher concentration of red cells in the glomerulus with a strong staining for Vascular Endothelial Growth Factor (VEGF). The introduction of GBE (therapeutic dose) in health rats may promote alterations in the physiology of the kidney, but no sufficient to modify the glomerulus architecture, including at ultra structural level (electron microscopy).

Evaluation of the acute toxicity of dolabelladienotriol, a potential antiviral from the brown alga Dictyota pfaffii, in BALB/c mice

Dolabelladienotriol is a product extracted from the brown marine alga Dictyota pfaffii from Brazil that has been shown to have antiviral activity and low cytotoxicity. Our studies have evaluated the acute toxicity of dolabelladienotriol in BALB/c mice for ten days after administration of a single dose. Among the parameters considered were behavior, weight, biochemical and histological analyses of blood samples taken at three different times (Bs.0, Bs.1 and Bs.2) and optical microscopic examination of organs like liver, kidney, stomach and small intestine. Mice deaths were not observed at any dose during the ten day period. There were some changes in the biochemical analysis results for urea nitrogen (BUN) and alanine aminotransferase (ALT), but the changes were not significantly different from the reference levels of the animals before administration of the substance. Histological analyses of tissues were very similar for all animals. The alterations in liver and kidney tissues did not affect the animals´ behavior at any concentration, not even at 50 mg/kg, where the most significant changes in tissues were seen. This study indicates that dolabelladienotriol has low toxicity in administered dose range.