Exaggerated production of nitric oxide (NO) and increases in inducible NO-synthase mRNA levels induced by the pro-inflammatory cytokine interleukin-1beta in vascular smooth muscle cells of elderly rats

Antipyretic Potential of 80% Methanol Extract and Solvent Fractions of Bersama abyssinica Fresen. (Melianthaceae) Leaves Against Yeast-Induced Pyrexia in Mice

Introduction

Since fever is a complicated physiological reaction to an infection or aseptic stimulus, finding safer solutions that are more potent and derived from plants is essential to resolving this issue. Bersama abyssinica (Melianthaceae) is traditionally used to treat fever, though this has yet to be proven scientifically.

Objective

The present study aimed to assess the antipyretic potential of leaf extract and solvent fractions of B. abyssinica.

Methods

The antipyretic activities of crude extract and solvent fractions of B. abyssinica leaves were evaluated using a yeast-induced pyrexia model at three different dose ranges (100mg/kg, 200mg/kg, and 400mg/kg) methanol extract as well as chloroform, ethyl acetate, and aqueous fractions to mice showing an increase in temperature of ≥0.5 °C. The rectal temperature of each mouse was recorded using a digital thermometer. To analyze the data, SPSS version 20 and one-way ANOVA followed by Tukey's HSD post hoc test to compare results between groups were utilized.

Results

The crude extract demonstrated significant antipyretic potential (P<0.05 by 100 mg/kg and 200 mg/kg as well as P<0.01 by 400 mg/kg), with a maximum of 95.06% reduction in rectal temperature at 400 mg/kg, comparable to 98.37% at 2.5 hours by the standard drug. Similarly, all doses of the aqueous fraction, as well as 200 mg/kg and 400 mg/kg doses of the ethyl acetate fractions, resulted in a significant (P<0.05) reduction in rectal temperature when compared to the corresponding value of the negative control group.

Conclusion

Extracts of B. abyssinica leaves were found to have a significant antipyretic effect. Thus, the use of the plant for pyrexia in traditional settings has scientific ground.

The role of p53 in the alternation of vascular functions

Ageing is a risk factor for many degenerative diseases. Cardiovascular diseases (CVDs) are usually big burdens for elderly, caregivers and the health system. During the aging process, normal functions of vascular cells and tissue progressively lost and eventually develop vascular diseases. Endothelial dysfunction, reduced bioavailability of endothelium-derived nitric oxide are usual phenomena observed in patients with cardiovascular diseases. Myriad of studies have been done to investigate to delay the vascular dysfunction or improve the vascular function to prolong the aging process. Tumor suppressor gene p53, also a transcription factor, act as a gatekeeper to regulate a number of genes to maintain normal cell function including but not limited to cell proliferation, cell apoptosis. p53 also crosstalk with other key transcription factors like hypoxia-inducible factor 1 alpha that contribute to the progression of cardiovascular diseases. Therefore, in recent three decades, p53 has drawn scientists’ attention on its effects in vascular function. Though the role of tumor suppressor gene p53 is still not clear in vascular function, it is found to play regulatory roles and may involve in vascular remodeling, atherosclerosis or pulmonary hypertension. p53 may have a divergent role in endothelial and vascular muscle cells in those conditions. In this review, we describe the different effects of p53 in cardiovascular physiology. Further studies on the effects of endothelial cell-specific p53 deficiency on atherosclerotic plaque formation in common animal models are required before the therapeutic potential can be realized.

Analgesic, anti-inflammatory and antipyretic activities of ethanolic extract of stem bark of Anogeissus latifolia Roxb

Background

Stem bark of Anogeissus latifolia Roxb (family: Combretaceae) is used traditionally and ethnomedicinally to alleviate pain, inflammation and fever conditions. The current study investigates the analgesic, anti-inflammatory and antipyretic activities of ethanolic extract of stem bark of Anogeissus latifolia Roxb.

Method

The HPLC studies were carried out to standardize the stem bark ethanolic extract of Anogeissus latifolia (ALEE) using ellagic acid as a marker. ALEE was screened for analgesic (formalin-induced pain and acetic acid induced writhing) and anti-inflammatory (formalin and carrageenan-induced paw oedema) activities in Wistar rats. Before 1 h of acetic acid or formalin or carrageenan injection, rats were orally fed with ALEE (100, 200 and 400 mg/kg), Aspirin (100 mg/kg) or Indomethacin (10 mg/kg). Antipyretic effect was studied in brewer’s yeast-induced pyrexia model in rats using Paracetamol (100 mg/kg) as a standard drug.

Results

HPLC analysis of ALEE revealed the presence of ellagic acid. ALEE treatment (200 and 400 mg/kg) significantly inhibited pain response in both models. ALEE treatments prevented the raise of paw volume in both in-vivo models with percent inhibition of 44.40 and 46.21, respectively at 5 h. ALEE also showed a significant reduction of yeast-induced pyrexia till 4 h of treatment.

Conclusion

ALEE exhibited analgesic, anti-inflammatory and antipyretic property in experimental models and validates traditional use of ALEE in pain, inflammation and fever.

MicroRNAs in cardiovascular health: from order to disorder

In the last decade, microRNAs (miRNAs) have revolutionized how we understand metabolism and disease. These small, 20- to 22-nucleotide RNA molecules fine-tune gene expression and can often coordinate multiple genes in a single pathway. Given the multifactorial nature of cardiovascular disease, it is perhaps not surprising that miRNAs have been shown to orchestrate many aspects of disease development, from modulating metabolic risk factors over a lifetime (eg, cholesterol and hormones) to controlling the response to an acute cardiovascular event (eg, inflammation and hypoxia). In this review, we discuss how miRNAs exert control over metabolic pathways that maintain vascular health and, when these pathways go awry, how miRNAs can be targeted for therapeutic modulation.

Estrogen and the cardiovascular system

Estrogen is a potent steroid with pleiotropic effects, which have yet to be fully elucidated. Estrogen has both nuclear and non-nuclear effects. The rapid response to estrogen, which involves a membrane associated estrogen receptor(ER) and is protective, involves signaling through PI3K, Akt, and ERK 1/2. The nuclear response is much slower, as the ER-estrogen complex moves to the nucleus, where it functions as a transcription factor, both activating and repressing gene expression. Several different ERs regulate the specificity of response to estrogen, and appear to have specific effects in cardiac remodeling and the response to injury. However, much remains to be understood about the selectivity of these receptors and their specific effects on gene expression. Basic studies have demonstrated that estrogen treatment prevents apoptosis and necrosis of cardiac and endothelial cells. Estrogen also attenuates pathologic cardiac hypertrophy. Estrogen may have great benefit in aging as an anti-inflammatory agent. However, clinical investigations of estrogen have had mixed results, and not shown the clear-cut benefit of more basic investigations. This can be explained in part by differences in study design: in basic studies estrogen treatment was used immediately or shortly after ovariectomy, while in some key clinical trials, estrogen was given years after menopause. Further basic research into the underlying molecular mechanisms of estrogen's actions is essential to provide a better comprehension of the many properties of this powerful hormone.

Antiinflammatory, antinociceptive and antipyretic effects of hydroethanolic extract from Macrosiphonia velame (A. St.-Hil.) M. Arg. in animal models

Macrosiphonia velame (Apocynaceae), popularly known as "velame-branco", is mainly used for treating inflammatory conditions. The antiinflammatory, antinociceptive and antipyretic effects of the hydroethanolic extract of the xylopodium from M. velame (HEMv) were evaluated using several animal models. HEMv showed low acute oral toxicity with LD50 of 4.176 ± 218.5 mg/kg in mice. In tests of carrageenan and dextran-induced paw edema and carrageenan-induced pleurisy in rats, and croton oil-induced cutaneous dermatitis in mice, HEMv presented systemic and topical antiinflammatory activities. In experiments of nociception induced by acetic acid, formalin and capsaicin in mice, the HEMv evidenced an antinociceptive effect, being active against both inflammatory and neurogenic pain. Additionally, the HEMv prevented brewer's yeast-induced pyrexia in rats. It is likely that the pharmacologic mechanism of HEMv may involve the inhibition of different mediators of the inflammatory response, such as histamine, serotonin, prostaglandins and leukotrienes. A preliminary phytochemical study was also undertaken on HEMv, which revealed the presence of flavonoids, phenolic compounds, pentacyclic triterpenoids, saponins, coumarins, catechins, tannins, and alkaloids. Taken together, these results suggest that M. velame extract has antiinflammatory, antinociceptive and antipyretic properties and further validate the traditional use of this plant in inflammatory conditions.

Age-related changes in redox signaling and VSMC function

Epidemiological studies have shown that advancing age is associated with an increased prevalence of cardiovascular disease (CVD). Vascular smooth muscle cells (VSMC) comprise the major arterial cell population, and changes in VSMC behavior, function, and redox status with age contribute to alterations in vascular remodeling and cell signaling. Over two decades of work on aged animal models provide support for age-related changes in VSMC and/or arterial tissues. Enhanced production of reactive oxygen species (ROS) and insufficient removal by scavenging systems are hallmarks of vascular aging. VSMC proliferation and migration are core processes in vascular remodeling and influenced by growth factors and signaling networks. The intrinsic link between gene regulation and aging often relates directly to transcription factors and their regulatory actions. Modulation of growth factor signaling leads to up- or downregulation of transcription factors that control expression of genes associated with VSMC proliferation, inflammation, and ROS production. Four major signaling pathways related to the transcription factors, AP-1, NF-kappaB, FoxO, and Nrf2, will be reviewed. Knowledge of age-related changes in signaling pathways in VSMC that lead to alterations in cell behavior and function consistent with disease progression may help in efforts to attenuate age-related CVD, such as atherosclerosis.

Mollaret meningitis may be caused by reactivation of latent cerebral toxoplasmosis

Mollaret meningitis (MM) occurs mainly in females and is characterized by recurrent episodes of headache, transient neurological abnormalities, and the cerebrospinal fluid containing mononuclear cells. HSV-2 was usually identified as the causative agent. Recently, we found that recurrent headaches in non-HIV-infected subjects were due to acquired cerebral toxoplasmosis (CT). The aim of the study was therefore to focus on molecular pathomechanisms that may lead to reactivation of latent CT and manifest as MM. Literature data cited in this work were selected to illustrate that various factors may affect latent CNS Toxoplasma gondii infection/inflammation intensity and/or host defense mechanisms, i.e., the production of NO, cytokines, tryptophan degradation by indoleamine 2,3-dioxygenase, mechanisms mediated by an IFN-gamma responsive gene family, limiting the availability of intracellular iron to T. gondii, and production of reactive oxygen/nitrogen species, finally inducing choroid plexitis and/or vasculitis. Examples of triggers revealing MM and accompanying disturbances of IFN-gamma-mediated immune responses that control HSV-2 and T. gondii include: female predominance (female mice are more susceptible to T. gondii infection than males); HSV-2 infection (increased IFN-gamma, IL-12); metaraminol (increased plasma catecholamine levels, changes in cytokine expression favoring T(H)2 cells responses); probably cholesterol contained in debris from ruptured epidermoid cysts (decreased NO; increased TNF-alpha, IL-6, IL-8). These irregularities induced by the triggers may be responsible for reactivation of latent CT and development of MM. Thus, subjects with MM should have test(s) for T. gondii infection performed obligatorily.

Exercise training modulates the nitric oxide synthase profile in skeletal muscle from old rats

The effects of exercise training on the nitric oxide synthase (NOS) isoform profile in aging fast-twitch (white gastrocnemius [WG]) and slow-twitch (soleus [SOL]) muscle have not been investigated. Six-month and 27-month male Fischer-344 rats were divided into the following groups: young sedentary (YS), young treadmill exercise trained for 12 weeks, old sedentary (OS), and old exercise trained (OE). Inducible NOS (iNOS) protein expression and activity were significantly higher in OS compared with YS, whereas exercise training significantly reduced iNOS protein and activity levels in the WG. Neuronal NOS protein expression decreased with aging in WG but was upregulated significantly with exercise training in OE for both WG and SOL. Endothelial NOS (eNOS) protein levels were depressed in WG of old rats but were higher in OE than in OS. eNOS was unaffected by aging or exercise in the SOL. Our results indicate that endurance exercise training attenuates age-induced alterations of NOS isoforms with a greater response in fast-twitch compared with slow-twitch muscle.

Aging, smooth muscle cells and vascular pathobiology: Implications for atherosclerosis

Epidemiological and autopsy studies suggest a close link between aging and the clinical manifestation of atherosclerosis. Several experiments show increased arterial susceptibility to atherogenetic stimuli in aged subjects. All together, these findings support the concept that aging represents an independent atherogenetic risk factor, intimately associated to other parietal, microenvironmental and systemic noxae. Smooth muscle cells (SMCs) represent the major arterial cell population. As aging occurs, SMCs progressively migrate from the tunica media and accumulate into the tunica intima. Myointimal thickening may represent the site where low-grade atherogenic stimuli cause early development and more severe lesion progression. Intimal SMC accumulation is characterized from a switch, from a differentiated to a synthetic phenotype, with reduced myocytic cytoskeletal markers and the expression of new proteins. Aging also associates to changes of SMC proliferative and apoptotic behavior and response to growth factors, such as transforming growth factor-beta1. The alteration of SMC properties represents a crucial event in the pathobiology of arterial wall, since it contributes to the vascular remodeling and decline of function with aging and favors the progression of atherosclerosis. Increased knowledge of biomolecular mechanisms regulating these events helps to develop new strategies aimed at contrasting the adverse effect of vascular aging.

Involvement of nitric oxide-mediated intrinsic pathway signaling in age-related increase in germ cell apoptosis in male Brown-Norway rats

We examined, using young and old Brown-Norway rats, the involvement of the nitric oxide (NO)-mediated intrinsic pathway signaling in age-related activation of male germ-cell apoptosis. Increased apoptosis of germ cells was readily observed in the normal-looking testes of old rats. Testicular NO synthase (NOS) activity, assessed by measuring the synthesis of (3)H-L-citrulline from (3)H-L-arginine, and cytokine-inducible NO synthase (iNOS) levels, assessed by western blot assay, were increased significantly by 90% and 70%, respectively, in the old rats compared to that of young animals. Immunohistochemical analysis of age-related changes in the expression of iNOS in testes confirmed our findings based on western blot assay. Increased NO and germ-cell apoptosis during aging is further associated with cytosolic translocation of mitochondrial cytochrome c and poly (ADP) ribose polymerase (PARP) cleavage, thus, suggesting the involvement of NO-mediated intrinsic pathway signaling in age-related increase in germ-cell apoptosis in male Brown-Norway rats.