Physiological and immunological changes in the brain associated with lethal eastern equine encephalitis virus in macaques

Aerosol exposure to eastern equine encephalitis virus (EEEV) can trigger a lethal viral encephalitis in cynomolgus macaques which resembles severe human disease. Biomarkers indicative of central nervous system (CNS) infection by the virus and lethal outcome of disease would be useful in evaluating potential medical countermeasures, especially for therapeutic compounds. To meet requirements of the Animal Rule, a better understanding of the pathophysiology of EEEV-mediated disease in cynomolgus macaques is needed. In this study, macaques given a lethal dose of clone-derived EEEV strain V105 developed a fever between 2–3 days post infection (dpi) and succumbed to the disease by 6 dpi. At the peak of the febrile phase, there was a significant increase in the delta electroencephalography (EEG) power band associated with deep sleep as well as a sharp rise in intracranial pressure (ICP). Viremia peaked early after infection and was largely absent by the onset of fever. Granulocytosis and elevated plasma levels of IP-10 were found early after infection. At necropsy, there was a one hundred- to one thousand-fold increase in expression of traumatic brain injury genes (LIF, MMP-9) as well as inflammatory cytokines and chemokines (IFN-γ, IP-10, MCP-1, IL-8, IL-6) in the brain tissues. Phenotypic analysis of leukocytes entering the brain identified cells as primarily lymphoid (T, B, NK cells) with lower levels of infiltrating macrophages and activated microglia. Massive amounts of infectious virus were found in the brains of lethally-infected macaques. While no infectious virus was found in surviving macaques, quantitative PCR did find evidence of viral genomes in the brains of several survivors. These data are consistent with an overwhelming viral infection in the CNS coupled with a tremendous inflammatory response to the infection that may contribute to the disease outcome. Physiological monitoring of EEG and ICP represent novel methods for assessing efficacy of vaccines or therapeutics in the cynomolgus macaque model of EEEV encephalitis.     

Severe depletion of mucosal CD4+ T cells in AIDS-free simian immunodeficiency virus-infected sooty mangabeys

HIV-infected humans and SIV-infected rhesus macaques experience a rapid and dramatic loss of mucosal CD4+ T cells that is considered to be a key determinant of AIDS pathogenesis. In this study, we show that nonpathogenic SIV infection of sooty mangabeys (SMs), a natural host species for SIV, is also associated with an early, severe, and persistent depletion of memory CD4+ T cells from the intestinal and respiratory mucosa. Importantly, the kinetics of the loss of mucosal CD4+ T cells in SMs is similar to that of SIVmac239-infected rhesus macaques. Although the nonpathogenic SIV infection of SMs induces the same pattern of mucosal target cell depletion observed during pathogenic HIV/SIV infections, the depletion in SMs occurs in the context of limited local and systemic immune activation and can be reverted if virus replication is suppressed by antiretroviral treatment. These results indicate that a profound depletion of mucosal CD4+ T cells is not sufficient per se to induce loss of mucosal immunity and disease progression during a primate lentiviral infection. We propose that, in the disease-resistant SIV-infected SMs, evolutionary adaptation to both preserve immune function with fewer mucosal CD4+ T cells and attenuate the immune activation that follows acute viral infection protect these animals from progressing to AIDS.     

T regulatory cells: aid or hindrance in the clearance of disease?

CD4+ CD25+ T regulatory cells (Tregs) are classified as a subset of T cells whose role is the suppression and regulation of immune responses to self and non-self. Since their discovery in the early 1970s, the role of CD4+ CD25+ Tregs in both autoimmune and infectious disease has continued to expand. This review examines the recent advances on the role CD4+ CD25+ Tregs may be playing in various diseases regarding progression or protection. In addition, advances made in the purification and manipulation of CD4+ CD25+ Tregs using new cell markers, techniques and antibodies are discussed. Ultimately, an overall understanding of the exact mechanism which CD4+ CD25+ Tregs implement during disease progression will enhance our ability to manipulate CD4+ CD25+ Tregs in a clinically beneficial manner.     

Internal standard-based analysis of microarray data2--analysis of functional associations between HVE-genes

In this work we apply the Internal Standard-based analytical approach that we described in an earlier communication and here we demonstrate experimental results on functional associations among the hypervariably-expressed genes (HVE-genes). Our working assumption was that those genetic components, which initiate the disease, involve HVE-genes for which the level of expression is undistinguishable among healthy individuals and individuals with pathology. We show that analysis of the functional associations of the HVE-genes is indeed suitable to revealing disease-specific differences. We show also that another possible exploit of HVE-genes for characterization of pathological alterations is by using multivariate classification methods. This in turn offers important clues on naturally occurring dynamic processes in the organism and is further used for dynamic discrimination of groups of compared samples. We conclude that our approach can uncover principally new collective differences that cannot be discerned by individual gene analysis.     

Dual Effects of Hydrogen Sulfide Donor on Meiosis and Cumulus Expansion of Porcine Cumulus-Oocyte Complexes

Hydrogen sulfide (H₂S) has been revealed to be a signal molecule with second messenger action in the somatic cells of many tissues, including the reproductive tract. The aim of this study was to address how exogenous H₂S acts on the meiotic maturation of porcine oocytes, including key maturation factors such as MPF and MAPK, and cumulus expansion intensity of cumulus-oocyte complexes. We observed that the H₂S donor, Na₂S, accelerated oocyte in vitro maturation in a dose-dependent manner, following an increase of MPF activity around germinal vesicle breakdown. Concurrently, the H₂S donor affected cumulus expansion, monitored by hyaluronic acid production. Our results suggest that the H₂S donor influences oocyte maturation and thus also participates in the regulation of cumulus expansion. The exogenous H₂S donor apparently affects key signal pathways of oocyte maturation and cumulus expansion, resulting in faster oocyte maturation with little need of cumulus expansion.     

Parasite communities of Adriatic cage-reared fish

From June 2001 to March 2002, 7 semi-offshore facilities in the Adriatic Sea rearing sea bass Dicentrarchus labrax, sea bream Sparus aurata, sharpsnout bream Diplodus puntazzo and red sea bream Pagellus bogaraveo aged 1+, were monitored for the presence of protozoan and metazoan parasites. Obtained data sets of abundance and prevalence were used to evaluate the structure and dynamic of infra- and component parasite communities. In all hosts, except the red sea bream, dominant parasites were monogenean specialists, showing clear seasonality. Average infracommunity richness was very low, ranging from 1 to 3 parasites per fish, while at component community level, values ranged from 3 to 8, depending on host species. Based on low diversity indices and a moderate to high similarity coefficient between different facilities, it can be concluded that the parasitofauna of Adriatic cage-reared fish is a stable and impoverished stochastic assemblage, with monogeneans as the predominant parasitic group.     

Myocardial content of selected elements in experimental anthracycline-induced cardiomyopathy in rabbits

Cardiotoxicity represents the main drawback of clinical usefulness of anthracycline antineoplastic drugs. In this study, a content of selected elements (Ca, Mg, K, Se, Fe) in the post-mortem removed samples of the myocardial tissue was studied in three groups of rabbits: 1) control group (i.v. saline; n = 10); 2) daunorubicin-receiving animals (DAU; 3 mg/kg, i.v; n=11); 3) animals receiving cardioprotective iron-chelating agent dexrazoxane (DEX; 60 mg/kg, i.p.; n=5) prior to DAU. Drugs were administered once weekly for 10 weeks. 5–7 days after the last administration, cardiac left ventricular contractility (dP/dt_max) was significantly decreased in DAU-treated animals (745 ± 69 versus 1245 ± 86 kPa/s in the control group; P < 0.05), while in the DEX+DAU group it was insignificantly increased (1411 ± 77 kPa/s). Of the myocardial elements content studied, a significant increase in total Ca against control (16.2 ± 2.4 versus 10.6 ± 0.9 g/g of dry tissue; P < 0.05) was determined in the DAU-group, which was accompanied with significant decreases in Mg and K. In the heart tissue of DEX-pretreated animals, no significant changes of elements content were found as compared to controls, while the Ca content was in these animals significantly lower than in the DAU group (9.1 ± 0.4 versus 16.2 ± 2.4 g/g; P < 0.05). Hence, in this study we show that systolic heart failure induced by chronic DAU administration is primarily accompanied by persistent calcium overload of cardiac tissue and the protective action of DEX is associated with the restoration of normal myocardial Ca content.Published online: March 2005