Effects of midazolam on T-cell immunosuppressive response to surgical stress in mice

Alprazolam Prompts HIV-1 Transcriptional Reactivation and Enhances CTL Response Through RUNX1 Inhibition and STAT5 Activation

The HIV-1 pandemic is a significant challenge to the field of medicine. Despite advancements in antiretroviral (ART) development, 38 million people worldwide still live with this disease without a cure. A significant barrier to the eradication of HIV-1 lies in the persistently latent pool that establishes early in the infection. The “shock and kill” strategy relies on the discovery of a latency-reversing agent (LRA) that can robustly reactivate the latent pool and not limit immune clearance. We have found that a benzodiazepine (BDZ), that is commonly prescribed for panic and anxiety disorder, to be an ideal candidate for latency reversal. The BDZ Alprazolam functions as an inhibitor of the transcription factor RUNX1, which negatively regulates HIV-1 transcription. In addition to the displacement of RUNX1 from the HIV-1 5′LTR, Alprazolam potentiates the activation of STAT5 and its recruitment to the viral promoter. The activation of STAT5 in cytotoxic T cells may enable immune activation which is independent of the IL-2 receptor. These findings have significance for the potential use of Alprazolam in a curative strategy and to addressing the neuroinflammation associated with neuroHIV-1.

Clinical tolerance of dexamethasone in New Zealand white rabbits

Rabbits have been a popular pet and research species world-wide. In many clinical and research situations, controlling inflammation is necessary for the health of these animals. One of the first drugs commonly employed in veterinary medicine to suppress inflammatory responses is corticosteroids. Unfortunately, steroid use in rabbits is not universally accepted as they are perceived, based on their potent immunosuppressant activity, to negatively impact quality of life. This is may be due, in part, to the lack of well-developed dosing protocols in these animals. This study evaluated the impact of a 5-day IM dexamethasone (Dex, 0.5 mg/kg) protocol on the immunity and clinical health of the New Zealand rabbit. Through two experiments separated by a 10-day washout period, experiment 1 comprised 5-days of dosing with bleedings on day 0, 3, 5 and 7, where experiment 2 consisted of 5-days of dosing with bleedings on day 0, 3 and 5. Animals were monitored twice daily for changes in clinical health. Hematology, T cell subset phenotype, leukocyte cell cycle, histopathology, phagocytosis and oxidative formation were evaluated. Consistent with other species, 5-day dosing with Dex suppressed leukocytes, in particular the T cells (p ≤ 0.003). Interestingly, rabbits failed to show any adverse clinical signs throughout the entire study. This would imply that a 5-day IM Dex (0.5 mg/kg) dosing protocol is well tolerated by New Zealand white rabbits and could be used in rabbits suffering from inflammatory conditions or disease as long as the animal's immune status is closely monitored.

Cyclosporine-A Increases Spontaneous and Dopamine Agonist-Induced Locomotor Behavior in Normal Rats

Cyclosporine-A (CsA) has been increasingly used as an immunosuppressant concomitant with neural transplantation treatment for different degenerative disorders. However, the possible role that CsA itself may have in the recovery of transplant patients is not known. Some investigators have argued that clinical improvement following transplantation (e.g., myoblast) may be confounded by CsA administration. The present study was conducted to delineate CsA-induced behavioral alterations. Four groups of normal 5-wk old Sprague-Dawley rats (n = 8 per group) were utilized in two separate experiments. In both experiments, two groups of animals were used; each group either received daily injections of 15 mg/kg of CsA or olive oil for 32 days (experiment 1) and 21 days (experiment 2). Animals in both experiments were subsequently tested for nocturnal locomotor behavior. Animals in experiment 2 were further tested in passive avoidance task, motor coordination, and amphetamine-induced locomotor activity. Results demonstrated that CsA-treated animals were significantly hyperactive compared to controls across the 12-h nocturnal activity periods and in amphetamine-induced locomotor activity. No significant differences between the CsA- and vehicle-treated animals were observed in passive avoidance or in motor coordination. Postmortem analyses of dopamine and its metabolites in the striatum and olfactory tubercle did not show any significant differences between the CsA- and the vehicle-treated groups. In summary, CsA significantly increased nocturnal spontaneous and amphetamine-induced locomotor behavior, but the neurochemical correlates for these effects need to be investigated. In addition, while the present study demonstrated that CsA induced motor alterations, any possible effects CsA may have on neurological or dystrophic patients with motor dysfunctions remain to be determined.

Antiviral therapy for human rabies

Human rabies is virtually always fatal despite numerous attempts at aggressive therapy. Most survivors received one or more doses of rabies vaccine prior to the onset of the disease. The Milwaukee Protocol has proved to be ineffective for rabies and should no longer be used. New approaches are needed and an improved understanding of basic mechanisms responsible for the clinical disease in rabies may prove to be useful for the development of novel therapeutic approaches. Antiviral therapy is thought to be an important component of combination therapy for the management of human rabies, and immunotherapy and neuroprotective therapy should also be strongly considered. There are many important issues for consideration regarding drug delivery to the central nervous system in rabies, which are in part related to the presence of the blood-brain barrier and also the blood-spinal cord barrier. Ribavirin and interferon-α have proved to be disappointing agents for the therapy of rabies. There is insufficient evidence to support the continued use of ketamine or amantadine for the therapy of rabies. Minocycline or corticosteroids should not be used because of concerns about aggravating the disease. A variety of new antiviral agents are under development and evaluation, including favipiravir, RNA interference (for example, small interfering [si]RNAs) and novel targeted approaches, including interference with viral capsid assembly and viral egress.

Current and future approaches to the therapy of human rabies

Human rabies has traditionally been considered a uniformly fatal disease. However, recent decades have seen several instances in which individuals have developed clinical signs of rabies, but survived, usually with permanent neurologic sequelae. Most of these patients had received prophylactic rabies vaccine before the onset of illness. The best outcomes have been seen in patients infected with bat viruses, which appear to be less virulent for humans than strains associated with other rabies vectors. In 2003, an article by rabies experts suggested that survival might be improved through a combination of vaccine, anti-rabies immunoglobulin, antiviral drugs and the anesthetic ketamine, which had shown benefit in an animal model. One year later, a girl in Milwaukee who developed rabies after bat exposure was treated with some of these measures, plus a drug-induced (therapeutic) coma, and survived her illness with mild neurologic sequelae. Although the positive outcome in this case has been attributed to the treatment regimen, it more likely reflects the patient's own brisk immune response, as anti-rabies virus antibodies were detected at the time of hospital admission, even though she had not been vaccinated. This conclusion is supported by the failure of the "Milwaukee Protocol" to prevent death in numerous subsequent cases. Use of this protocol should therefore be discontinued. Future research should focus on the use of animal models to improve understanding of the pathogenesis of rabies and for the development of new therapeutic approaches.

Metagenomic and metabolomic characterization of rabies encephalitis: new insights into the treatment of an ancient disease

Rabies virus (RV) infection is a fatal nervous system disorder. We describe a patient who died of rabies despite a neuroprotective intervention. Neuropathology showed neuronal loss with abundant RV antigen, genome, and Negri bodies, accompanied by intense neuroinflammation, including by CD8(+) T lymphocyte infiltrates. Deep sequencing and real-time reverse-transcription polymerase chain reaction revealed RNA encoding a bat RV strain together with inflammatory gene induction. RV-infected brain demonstrated reduced neuronal metabolites with an anaerobic metabolic profile by nuclear magnetic resonance (NMR) spectroscopy. These multiplatform studies highlight the extent of ongoing viral replication coupled with inflammation in treated rabies, indicative of a neurological immune reconstitution inflammatory syndrome.

Effects of psychological stress and alprazolam on development of oral candidiasis in rats

Psychological stress has been found to suppress cell-mediated immune responses that are important in limiting the proliferation of Candida albicans. Since anxiolytic drugs can restore cellular immunity in rodents exposed to stress conditions, we designed experiments conducted to evaluate the effects of alprazolam (1 mg/kg of body weight/day), a central benzodiazepine anxiolytic agonist, on the development of oral candidiasis in Sprague-Dawley rats exposed to a chronic auditory stressor. Animals were submitted to surgical hyposalivation in order to facilitate the establishment and persistence of C. albicans infection. Application of stress and treatment with drugs (placebo or alprazolam) were initiated 7 days before C. albicans inoculation and lasted until the end of the experiments (day 15 postinoculation). Establishment of C. albicans infection was evaluated by swabbing the inoculated oral cavity with a sterile cotton applicator on days 2 and 15 after inoculation, followed by plating on YEPD (yeast extract-peptone-dextrose) agar. Tissue injury was determined by the quantification of the number and type (normal or abnormal) of papillae on the dorsal tongue per microscopic field. A semiquantitative scale was devised to assess the degree of colonization of the epithelium by fungal hyphae. Our results show that stress exacerbates C. albicans infection of the tongues of rats. Significant increases in Candida counts, the percentage of the tongue's surface covered with clinical lesions, the percentage of abnormal papillae, and the colonization of the epithelium by fungal hyphae were found in stressed rats compared to those found in the unstressed rats. Treatment with alprazolam significantly reversed these adverse effects of stress, showing that, besides the psychopharmacological properties of this anxiolytic drug against stress, it has consequences for Candida infection.

Effects of nefazodone on the immune system of mice

Mice exposed to a chronic auditory stressor and treated with nefazodone (10 mg/kg/day s.c.), showed a reduction in stress-induced suppression of thymus and spleen cellularity, and in peripheral T-Iymphocyte population. The in vitro blastogenic response of spleen lymphoid cells to mitogen concanavalin A, the in vitro and in vivo activity of phagocytosis, both measured using the zymosan and carbon clearance tests, respectively, were also assessed and nefazodone was found to partially reverse the inhibitory effect of stress on those parameters. Nefazodone did not significantly affect those parameters in unstressed mice. In conclusion, this report provides evidence on the immunoprotective effects of this novel antidepressant drug against the adverse effects of stress in mice.

Proactive influence of a surgical stressor on locomotor activity, exploration and anxiety-related behaviour following acute footshock in the mouse

The putative proactive influence of graded surgical stressors including intraventricular cannulation, sham surgery and no surgery on footshock-associated variations of locomotor activity, rearing and anxiogenic behaviour in the light-dark paradigm was evaluated among CD-1 mice. Neither sham surgery nor cannulation of the lateral ventricle altered baseline measures of locomotor activity or rearing relative to the performance of nonoperated control animals. Cannulation exacerbated the depressant influence of acute footshock on locomotor activity, while sham surgery mitigated the disruptive effect of the stressor on locomotor activity during the initial 15-min period of the test session. Footshock suppressed the vertical activity scores of mice regardless of surgical history. Only intraventricular cannulation reduced the baseline time in light scores of mice in the light-dark paradigm with repeated testing relative to animals in the sham surgery and no-surgery conditions. Baseline transition scores were not differentially affected by surgical history. Typically, transition scores were reduced on day 2 relative to day 1, but additional performance decrements were precluded on day 3. Footshock interacted with the surgical stressor of intraventricular cannulation in exaggerating reduced time in light relative to the performance of mice in the remaining surgical conditions. Transition frequency was not differentially influenced by the nature of the surgical stressor and subsequent exposure to footshock. The implications of these data for stressor-induced pathology are discussed.

Benzodiazepines, anxiety and immunity

Experimental and clinical studies suggest that the central and peripheral benzodiazepine (BDZ) receptors together with their ligands form the molecular basis of a novel regulatory network that contributes to the effects of anxiety on immune status. The peripheral-type receptors located on phagocytes and glial cells appear to play a key role in mediating the effects of endogenous and exogenous BDZs both on the defence mechanisms that protect the host against pathogens and on inflammatory reactions that take place within the periphery and the brain in response to injury. In addition, the central-type receptor, which forms part of the gamma-aminobutyric acidA receptor complex, may contribute to the regulation of T-cell function by modulating the activity of the hypothalamo-pituitary-adrenocortical axis or the sympathoadrenal system or both, which, in turn, exert a significant effect on immune function. Thus, anxiogenic BDZs in general suppress the immune response, whereas anxiolytic BDZs may protect the individual from stress-induced immunosuppression.

Effects of fluoxetine on the immunosuppressive response to stress in mice

Mice exposed to a chronic auditory stressor and treated with fluoxetine (5 mg/kg) showed a reduction in stress-induced suppression of thymus and spleen cellularity, and in peripheral T lymphocyte population. The blastogenic response of spleen lymphoid cells and the delayed type hypersensitivity response (DTH) to sheep red blood cells (SRBC) were also assessed and fluoxetine was found to partially reverse the inhibitory effect of stress on both parameters.

Cyclosporine-A increases locomotor activity in rats with 6-hydroxydopamine-induced hemiparkinsonism: relevance to neural transplantation

BACKGROUND

The immunosuppressant cyclosporine-A (CsA) is the primary drug for neural transplantation in Parkinson's disease. However, little is known of its direct effects on movement disorders. Our previous observation of increased locomotor activity in normal rats injected with CsA prompted us to investigate further the effects of CsA on hemiparkinsonian rats.

METHODS

We examined the effects of CsA with 6-hydroxydopamine-induced hemiparkinsonism. The animals were randomly assigned to either intraperitoneal injections of CsA (15 mg/kg) or olive oil (the vehicle used for CsA) for 32 days. All animals were tested using the elevated body swing test, and the spontaneous and the amphetamine-induced rotational tests prior to and following the 32-day drug regimen.

RESULTS

As revealed by the elevated body swing test, CsA-treated rats had significantly higher mean percent contralateral (to the lesion) swings compared to their pretreatment level (p < 0.01) or to vehicle-treated rats at posttreatment (p < 0.005). In the spontaneous rotational test, CsA-treated rats displayed ipsilateral (to the lesion) rotations which were significantly higher than their pretreatment rotational behavior (p < 0.005) or the posttreatment rotational behavior of olive oil-treated rats (p < 0.0001). Similarly, CsA-treated rats displayed significantly more amphetamine-induced ipsilateral rotations compared to their or the olive oil-treated rats pretreatment level (p < 0.05).

CONCLUSION

Our present observations extend our previous findings on motor alterations produced by CsA on normal rats to hemiparkinsonian rats. These results taken together would suggest that CsA may interact with the locomotor effects observed following neural transplantation with adjunctive CsA immunosuppression.

Effects of buspirone on the immune response to stress in mice

Several experiments were conducted to evaluate the effects of buspirone, a selective 5-hydroxytryptamine-1A (5-HT1A) anxiolytic, on the immune system of mice exposed to a chronic auditory stressor. Daily injection with 0.5 and 1 mg/kg (intraperitoneally) of buspirone resulted in a dose-dependent reduction in the stress-induced suppression of the natural killer (NK) cell activity and the in vitro and in vivo activity of phagocytosis. Higher doses of buspirone (2.0 mg/kg) showed less robust immunoenhancing effects in stressed mice, and caused a significant suppression of these immune parameters in unstressed mice.